SODIUM OMADINE

SODIUM OMADINE

SODIUM OMADINE

SODIUM OMADINE = SODIUM PYRITHIONE = Sodium-2-pyridinethiol-1-oxide = 2-Mercaptopyridine-N-oxide, sodium salt

EC Number: 223-296-5 ; 240-062-8
CAS Number: 3811-73-2; 15922-78-8

EC / List no.: 223-296-5
CAS no.: 3811-73-2
Mol. formula: C5H5NOS.Na

EC / List no.: 240-062-8
CAS no.: 15922-78-8
Mol. formula: C5H4NNaOS

Sodium-2-pyridinethiol-1-oxide (Sodium-Omadine) is a bactericide and preservative found in coolants, make-up removers, paints, lubricants, and latex.

Antimicrobial preservative (sodium pyrithione) used in a variety of water-based functional fluids and coatings to protect against micro-organisms.

Sodium omadine is a broad spectrum antimicrobial compound used as a preservative in certain manufacturing materials and as additive in process fluids which may otherwise be subject to deterioration through bacterial and/or fungal growth.
Sodium omadine may be used as a biocide in: aqueous metalworking, cutting, cooling and lubricating fluids; latex emulsions used in adhesives, caulks, patching compounds, sealants, pastes and grouts; latex emulsions; aqueous fiber lubricants and inks; laundry rinse additives and detergents; carpet cleaners and analytical and diagnostic reagents

SODIUM OMADINE 40 % Fungicide is an amber colored liquid broad spectrum anti-fungal agent.
SODIUM OMADINE 40 % is effective against most fungi, yeasts, and molds commonly found in contaminated metalworking fluid systems.
SODIUM OMADINE 40 % is one of the few effective water-soluble fungicides available for use by this industry, and an excellent choice as a post treatment additive.
SODIUM OMADINE 40 % Fungicide is for use in metalworking, cutting, cooling, and lubricating fluids.

Sodium pyrithione is currently the most effective water-soluble industrial mildew preservative, with high efficiency, broad spectrum, low toxicity and stability.
Sodium pyrithione can be used in metal cutting fluids, anti-rust liquids, latex paints, adhesives, leather products, textile Products, copper paper, etc.
Sodium pyrithione Antibacterial agent has the characteristics of high efficiency, broad spectrum, low toxicity and stable aqueous solution.
The main application areas of Sodium pyrithione include: daily chemical products, adhesives, paper, medicine, pesticides, leather products, disinfection products.

Sodium Pyrithione is an organosulfur compound with broad spectrum antimicrobial, provides excellent inhibition of the growth of bacteria and fungi in a many household and industrial products, such as shampoo, hair care products, laundry products and surface cleaning products, pesticides, textile&leather treatment, etc.

Sodium pyrithione acts as a biocide (antibacterial, antiviral and anti-fungal).
Sodium pyrithione belongs to a class of cyclic sulfur organo products containing sulfur atom (S) and often oxygen (O), nitrogen (N), hydrogen (H).

GRADES:

Sodium Pyrithione 40% solution
Appearance: light yellow or yellow-brown clear liquid
Solubility: soluble in water and organic solvents like ethanol.
Content: 40 % min.
pH value: 9 – 11

Sodium Pyrithione powder
Appearance: off-white powder
Content: 98 % min.
pH value: 8.5 – 10.5

Application

Sodium Pyrithione is currently the most effective water-soluble industrial mildew preservative.

Widely used in the fields of daily chemicals (shampoo and hair care products),  latex paint, adhesive, leather products, textile，architectural coatings, adhesives, sealants, pesticides,  metalworking fluids，anti-rust liquidetc etc.

Sodium Pyrithione can also formulate products such as disinfectants, astringents and medical broad-spectrum antifungal dermatology drugs.
At the same time, Sodium Pyrithione is an effective fungicide for fruit trees, peanuts, wheat, vegetables and other crops and an excellent disinfectant for silkworm.

Sodium Pyrithione and its similar products are widely used in related fields for their high efficiency, broad spectrum, and low toxicity.

Application:

1) Sodium Pyrithione is widely used in daily chemicals (Shampoo and hair conditioner products) building coating, sealing, sticking, pesticide, textile, leather, metalworking fluid and so on, it is effective antimicrobial to bacterial.

2) Sodium Pyrithione is also used to formulate disinfectant and medical spectrum antifungal skin.

3) Sodium Pyrithione is also used as a biocide and disinfectant for fruit trees, wheat, vegetables, and silkworm.

4) Sodium Pyrithione and the other similar product are widely used in the filed, with high effect, wide spectrum and low toxic advantage.

SODIUM OMADINE is one of the active components in paint, sealants, shampoo, adhesive and aerosol due to its anti-microbial activity.
In biochemistry studies, SODIUM OMADINE is utilized to transport zinc into cells. Further, it is used to form bidentate oxothiolane chelates with transition metals.
SODIUM OMADINE acts as a stabilizer and viscosity building provider in weak basic or neutral medium.

Solubility
Soluble in water, ethanol, propylene glycol, polyethylene glycol and dimethyl sulfoxide. Insoluble in liquid paraffin and olive oil.

Notes
Hygroscopic. Incompatible with strong oxidizing agents.

NaPT 40 is a formaldehyde free pH stable fungicide, effective against fungi and yeasts.

Sodium Omadine is a zero-VOC solution of the trusted antimicrobial sodium pyrithione, and can effectively inhibit the growth of bacteria and fungi in a wide variety of household products in areas such laundry care, surface cleaning and aircare.

Pyrithione Sodium is the sodium salt form of pyrithione, a fungistatic and antimicrobial derivative of aspergillic acid.
Although the exact mechanism of action remains to be fully elucidated, pyrithione sodium appears to interfere with membrane transport ultimately leading to a loss of metabolic control.

Sodium Omadine 40%
SODIUM OMADINE 40% AQUEOUS SOLUTION

Pyridine-2-thiol 1-oxide, sodium salt

Sodium omadine is a Broad-spectrum antimicrobial and it has excellent heat and pH stability.

Sodium omadine contains Zero VOCs and it is Extensively tested toxicology and environmental profile
Sodium Omadine 40% is a fungicide, 40% active content, formaldehyde free, pH stable aqueous solution designed for concentrates and tankside use.
Avoid use in cast iron grinding applications

Sodium-2-pyridinethiol-1-oxide (Sodium-Omadine) is a bactericide and preservative found in coolants, make-up removers, paints, lubricants, and latex.

Synonyms: 1-Hydroxy-2-pyridinethione sodium salt; 2-Mercaptopyridine-1-oxide sodium salt; 2-Pyridinethiol-1-oxide sodium salt; Pyrithione sodium salt; Natrium-Pyrion
CAS: 3811-73-2

(1-Hydroxy-2-pyridinethione), sodium salt, tech.
Omadine sodium
Sodium omadine (VAN)
Sodium pyrithione (VAN)
Sodium 2-mercaptopyridine 1-oxide
Sodium 2-pyridinethiol N-oxide
Sodium 2-pyridinethiol 1-oxide
Sodium 2-pyridinethiolate 1-oxide
Sodium, (2-pyridinylthio)-, N-oxide
Thione (reagent)
WLN: T6NJ AO BSH &-NA-
1-Oxo-2-pyridinethiol sodium salt
2-Mercaptopyridine oxide sodium salt
2-Mercaptopyridine 1-oxide sodium salt
2-Mercaptopyridine-N-oxide sodium salt
2-Pyridinethiol N-oxide sodium salt
2-Pyridinethiol-1-oxide sodium salt
2-Pyridinethiol, N-oxide, sodium salt
2-Pyridinethiol, 1-oxide-, sodium salt
2-Pyridinethiol, 1-oxide, sodium salt (8CI9CI)

APPLICATIONS

Sodium Pyrithione inhibits the growth of fungi, yeast, mold and bacteria.
Sodium Pyrithione is used in formulating anti-microbial property in paint, sealants, shampoo, adhesive and aerosol. Amine N-oxides are active components in body care products such as shampoo, bubble bath, and hand-soap formulations as they are cationic and can act as a mild conditioner in acidic media.
In neutral or weak basic media, they are featured as excellent stabilizer and viscosity building provider.

Pyrithione N-oxide molecules
Product

CAS RN

Pyrithione    1121-30-8
2-Mercaptopyridine N-oxide
1121-31-9
Pyrithione zinc    13463-41-7
Pyrithione copper

154592-20-8
Pyrithione sodium    15922-78-8; 3811-73-2
Dipyrithione    3696-28-4
Bispyrithione magsulfex    67182-81-4
SALES SPECIFICATION
APPEARANCE

clear liquid

ACTIVE MATTER
40.0%

Sodium Omadine 40% Fungicide is a sodium pyrithione.

Sodium Omadine possesses high water solubility, high activity, non-irritating and non-sensitizing properties.
Sodium Omadine 40% Fungicide provides good short-term protection against bacteria and fungus.

Sodium Omadine is used as a bactericide for use in cooling fluids, paints and some lubricants.
Sodium Omadine is also used as a preservative for cosmetic rinse‐off products.

Sodium Omadine can be identified by different names, including:
2‐Mercaptopyridine‐N‐oxide, sodium salt
2‐Pyridinethiol‐1‐oxide, sodium salt
Mercaptopyridine‐N‐oxide sodium salt
N‐Hydroxy‐2‐pyridinethione, sodium salt
Sodium‐2‐pyridinethiol‐1‐oxide
sodium pyrithione

Sodium pyrithione, also known as omadine sodium, is an organosulfur compound with the molecular formula C5H4NNaOS.
Sodium pyrithione is the sodium salt form of pyrithione, a fungistatic and antimicrobial derivative of aspergillic acid.
Pyrithione sodium appears to interfere with membrane transport, leading to loss of metabolic control.
Sodium pyrithione is a broad spectrum antimicrobial, which inhibits the growth of bacteria and fungi in household and industrial products such as shampoos, hair care, laundry, surface cleaning, pesticides, and textile & leather treatment.
Sodium pyrithione is used as a broad spectrum biocide especially against fungi and gram positive and gram negative bacteria in metal working fluids, rubber & paint, and cosmetics industries.
At room temperature in the dark, sodium pyrithione is stable in the pH range 4.5 to 9.5.
At 100°C Sodium pyrithione is stable for at least 120 hours, at 150°C 29 % of the substance has decomposed within 48 hours.

USES OF 2-Mercaptopyridine-N-oxide, sodium salt, 40 w/w % aqueous solution

Household Products
• Cooling fluids
• Paints
• Synthetic fiber lubricants
• Vinyl acetate latex

Liquids
• Cosmetic rinse-off products

SODIUM OMADINE 40% Fungicide is a highly active, broad-spectrum antimicrobial agent that, when used at recommended concentrations, can help to prevent and minimize problems associated with fungal contamination. It is the 40% aqueous sodium salt derivative of pyrithione.

USES :
Metalworking fluids
Using Disinfectants or Biocides
Working with Glues and Adhesives

Sodium Omadine 40 % functions as a wet-state preservative against bacteria and fungus in latex paints.
Sodium Omadine 40 % is a highly active, very effective water soluble sodium pyrithione.
Sodium Omadine 40 % offers pronounced growth-inhibiting activity against both yeasts and molds.
Sodium Omadine 40% possesses non-irritating and non-sensitizing properties.

Sodium omadine Usage

1. Sodium pyrithione, also known as sodium pyrithione, sodium omepridine, pyrithione, and sodium α-mercaptopyridine-N-oxide, are pyridine derivative fungicides.

2. Appearance is yellow full light transparent liquid, melting point 250 ° C, soluble in water and ethanol and other organic solvents.

3. Unstable to light, oxidant and strong reducing agent. Nonionic surfactants make it slightly inactive, and it can chelate with heavy metals.

4. Main application areas: daily chemical products, adhesives, paper, medicine, pesticides, leather products, disinfection supplies.

In terms of application, the global sodium pyrithione market can be segmented into personal care industry, rubber industry, metal working fluids industry, and paints industry.
The personal care industry segment dominated the market in 2020.
Sodium pyrithione is utilized in the personal care industry to manufacture shampoos and hair care products.
Metal working fluids industry was the next major segment.
Sodium pyrithione is antimicrobial active, for the use in the metalworking industry.
Sodium pyrithione has increased efficacy against various microorganisms found in metalworking fluid systems.
In addition to its anticipated antifungal performance, sodium pyrithione also exhibits antibacterial efficacy.
Sodium Pyrithione is used as an antimicrobial agent in adhesives and in components of adhesives in paper towels for use in contact with aqueous and fatty foods.

Sodium pyrithione can effectively inhibit the growth of bacteria and fungi in a wide variety of household products in areas such laundry care, surface cleaning and aircare. Sodium pyrithione is primarily used in personal care products as an antimicrobial agent. Therefore, increase in awareness about personal hygiene and consumer expenditure is expected to drive the global sodium pyrithione market. Sodium pyrithione is toxic, and hence personal protective equipment (PPE) and engineering control equipment (chemical resistant gloves) are required in its manufacture. Availability of various substitutes such as zinc pyrithione acts as a restraint of the global sodium pyrithione market.

For Use in Metalworking Fluids
All types of aqueous based coolants are susceptible to contamination from bacteria, yeast, and mold.
Regardless of the type of coolant, bacteria are the most frequently detected microbes in used coolant.
Fungi (yeast and mold), while usually present, are not as easily detected by conventional methods, because the filamentous mycelial forms of mold tend to accumulate in machine crevices, in piping, on sump walls, gear boxes and other solid surfaces.
Routine attempts to completely eliminate bacteria through continual use (and sometimes overuse) of bactericides alone usually result in conditions that encourage the growth of yeast and mold. Heavy fungal contamination can often require both mechanical and chemical treatment.
Dumping, cleaning and recharging fluids are costly procedures.
Moreover, in today’s regulatory climate, disposal of used fluid can be expensive.
Therefore, it is important that the routine treatment of a system includes a fungicide, as well as a bactericide, to ensure longer system life and savings on replacement, cleaning, and disposal costs.
Sodium Omadine 40% fungicide is a highly active, broad-spectrum antimicrobial agent that, when used at recommended concentrations, can help to prevent and minimize problems associated with fungal contamination.
Sodium Omadine 40% fungicide is registered with the United States Environmental Protection Agency (US EPA Reg. No. 1258-843) under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), for use in metalworking, cutting, cooling and lubricating concentrates and enduse fluids.

Sodium pyridine
Product Category:anti-dandruff,antibacterial

Product Description:Alias: Sodium Omadine；2-Mercaptopyridine-N-oxide sodium salt
CAS NO: 3811-73-2
Molecular formula： C5H4NOSNa
Molecular weight：149.16
Appearance：Yellow or light yellow brown transparent liquid; solid is almost white powder
Density：1.22g/cm³
Solubility：Soluble in water

Purpose：
1. Used for shampoo to remove dandruff.
2. Chemical antibacterial agents are mainly used in daily chemical products, adhesives, papermaking, medicine, pesticides, leather products, disinfection products, etc.

sodium 2-pyridinethiol-1-oxide
(C5H4NOSNa)
CAS No. 3811-73-2
Molecular Wt. 149.2
Sodium Omadine 40% fungicide is the 40% aqueous sodium salt derivative of pyrithione.

Pyrithione is also known by any of the following names:
2-mercaptopyridine-N-oxide
1-hydroxypyridine-2-thione
2-pyridinethiol-1-oxide (CAS No. 1121-31-9)
1-hydroxy-2(1H)-pyridinethione (CAS No. 1121-30-8)

Product Specifications
Sodium 2-pyridinethiol-1-oxide (%): 40–42
Color, max. (Gardner): 8
pH @ 25°C, 10% in Distilled Water (4% Active): 8.5–10.5

Typical Physical Properties
Color: Amber
Odor: Mild
Specific Gravity @ 25°C: 1.2
Density @ 25°C: 10.6
Solubility in water: Complete
Melting Point, (solid decomposes): 250°C
Viscosity @ 25°C, (cp): 10.98

Chemical Properties
Clear solution

Uses
For chemistry of 2-mercaptopyridine-N-oxide, see Aldrichimica Acta.1

Uses
sodium pyrithione is a preservative that is not commonly used because of some level of toxicity.

Uses
Sodium omadine is a bactericide for use in cooling fluids and short-term in-can preservation of vinyl acetate latex, paints, and synthetic-fiber lubricants; preservative for cosmetic rinse-off products.

Sodium pyrithione is used as a broad spectrum biocide especially against fungi and gram positive and gram negative bacteria in metal-working fluids (boring and cutting oils, up to 0.5 % in the concentrate), in the rubber industry
(Wallhäusser 1984) and paint industry (dispersion paints, 0.05 %–0.2 %) (Clayton and Clayton 1981), and in cosmetics which are rinsed off, such as shampoos and wash lotions for the skin, in concentrations of 0.5 % (Lüpke and Preusser).

Definition
Apparently exists in equilibrium with the -SH form. Forms chelates with iron, manganese, zinc, etc.

brand name
Sodium Omadine (Olin).

Directions for Use
To inhibit the growth of fungi in aqueous metalworking, cutting, cooling and lubricating fluids: Add up to 1250 ppm (0.125% v/v) of Sodium Omadine 40% fungicide to the diluted fluid (1.25 gal per 1000 gal of solution).
Typical recommended dose levels are between 200 and 500 ppm, product as sold.
Different use and contamination conditions may require different levels of Sodium Omadine 40% fungicide and while compatible with most metalworking fluids physical and chemical compatibility testing is recommended.
When adding fresh diluted fluid to compensate for dragout or other losses, add Sodium Omadine 40% fungicide to make-up fluid according to the above directions.
Frequent checks (at least once per week) of the bacterial and fungal population in the system should be made using standard microbiological plate count procedures or any of the commercial “dip-stick” type devices.
When the fungal count reaches 102 organisms per milliliter or greater, add additional Sodium Omadine 40% fungicide according to the above directions.
The fluid should be checked at least once per day with a refractometer (or other suitable means) to determine if water loss by evaporation has occurred.
Make-up water should be added daily to compensate for such losses.
The fluid should be monitored at least once per week (depending on the metalworking operation involved) for the following: tramp oil, pH, odor, oil droplet size, and anticorrosion properties.
If any of these parameters is outside the specifications established for the system in question, they should be brought up to specifications by the addition of suitable additives or the fluid should be discarded and replaced after cleaning the system.
Add Sodium Omadine 40% fungicide to the fresh fluid according to the above directions.
Contaminated fluid systems should be cleaned prior to the addition of Sodium Omadine 40% fungicide. Drain the system, clean with a cleaner designed for this purpose, rinse with water, and refill with fresh fluid.
Sodium Omadine 40% fungicide may be added to the fluid at the time it is prepared (diluted) or to the reservoir (sump) containing the fluid after it is put into use.
If it is added to the reservoir, the fluid should be circulated after addition to ensure mixing

To inhibit the growth of fungi in aqueous metalworking, cutting, cooling and lubricating concentrates: Add an amount that will give up to 1250 ppm in the diluted fluid.
The amount required in the concentrate will depend on the end use dilution.
For example: If the desired level of Sodium Omadine 40% fungicide in the diluted fluid is 200 ppm, and the end use dilution of the fluid is 5%, then a 0.4% concentration of Sodium Omadine 40% fungicide is required in the concentrate (200 ppm/0.05 = 4,000 ppm or 0.4%).
Chemical Reactivity Oxidizing agents such as peroxides and hypohalites will convert pyrithione first to dipyrithione (2,2’-dithiobis-pyridine-1,1’-dioxide; CAS No. 3696-28-4), and finally to pyrithione sulfinic or sulfonic acid. Both are inactive microbiologically.
Strong reducing agents will react with the N-oxide group of pyrithione to give 2-mercaptopyridine or its derivatives.
These, too, are less active microbiologically than the parent compounds.
At times the addition of Sodium Omadine 40 % fungicide to aqueous systems may result in a blue color.
This is caused by the reaction of ferric ions with sodium 2-pyridinethiol-1-oxide to form iron tris (2-pyridinethiol-1-oxide), a highly colored water insoluble compound.
If iron tris (2-pyridinethiol-1- oxide) is a problem, Lonza can offer formulation assistance in preventing its formation.
Heat Stability Sodium Omadine 40% fungicide is stable at 100°C for at least 120 hours.
At 150°C, the assay of Sodium Omadine 40% fungicide decreases 29% during a 48-hour period.
The heat of decomposition, as measured under nitrogen by differential scanning calorimetry, is 158 cal/g for Sodium Omadine 40% fungicide.
pH Stability Sodium Omadine 40% fungicide can be used over the pH range from 4.5 to 11.0.
Below pH 4.5, the sodium salt is in equilibrium with free pyrithione.
Pyrithione is active microbiologically, but is very unstable in the presence of light or oxygen.
Light Stability Sodium Omadine 40% fungicide will gradually degrade when exposed to light, depending on the nature of the formulation.
Formulations containing Sodium Omadine 40% fungicide should be packaged in brown or opaque containers unless tests have shown that photodegradation is not a problem.

•    SODIUM-2-PYRIDINETHIOL-1-OXIDE
•    SODIUM PYRIDINE-2-THIOLATE 1-OXIDE HYDRATE
•    SODIUM PYRITHIONE
•    SODIUM OMADINE
•    PYRITHIONE SODIUM
•    PYRITHIONE SODIUM SALT
•    N-Hydroxy-2-pyridinethione sodium salt
•    N-HYDROXYPYRIDINETHIONE SODIUM SALT
•    2-PYRIDINETHIOL-1-OXIDE SODIUM SALT
•    1-HYDROXY-2-PYRIDINETHIONE SODIUM SALT
•    1-HYDROXY-2(1H)-PYRIDINETHIONE SODIUM SALT
•    1-HYDROXYPYRIDINE-2-THIONE SODIUM SALT
•    2,2-MERCAPTOPYRIDINE-N-OXIDE, SODIUM SALT
•    2-MERCAPTOPYRIDINE-1-OXIDE SODIUM SALT
•    2-MERCAPTOPYRIDINE N-OXIDE SODIUM SALT
•    MERCAPTOPYRIDINE N-OXIDE SODIUM SALT
•    (1-hydroxy-2-pyridinethione),sodiumsalt,tech.
•    2-pyridinethiol sodium salt, 40%+ in water
•    pyridine-2-thiol 1-oxide, sodium salt
•    Sodium pyrithione(NaPT)
•    2,2-Mercaptopyridine-N-oxide, sodium salt (40% sol.in H2O)
•    2-Mercaptopyridine-N-oxide Sodium
•    1-HYDROXYPYRIDINE-2-THIONE SODIUM
•    2-MERCAPTOPYRIDIN-1-OXIDE SODIUM SALT
•    2-Mercaptopyridine-N-oxide, sodium salt ,98%
•    2-MERCAPTOPYRIDINE-N-OXIDE, SODIUM SALT, 40 W/W% AQUEOUS SOLUTION
•    2-(Sodiothio)pyridine 1-oxide
•    Sodium, (2-pyridylthio)-, N-oxide
•    2-Mercaptopyridine N-oxide sodium salt solution, 40 wt. % in water
•    2-MERCAPTOPYRIDINE-1-OXIDE SODIUM SALT S OL., ~40% IN H2O
•    1-HYDROXYPYRIDINE-2-THIONE SODIUM*SIGMAU LTRA
•    2-Mercaptopyridine-N-oxide, sodium salt, 40% aq. soln.
•    NaPT
•    Sodium pyrithion
•    2-mercaptopyridine-1-oxide sodium salt solution
•    SODIUM PYRITHIONE, SODIUM 2-PYRIDINETHIOL-1-OXIDE
•    2-MERCAPTOPYRIDINE-N-OXIDESODIUMSALT(SODIUMPYRITHIONE)
•    2-MERCAPTOPYRIDINE N-OXIDE SODIUM SALT: 40% AQUEOUS SOLUTION
•    2-Mercaptopyridine N-Oxide Sodium Salt (35% in Water, ca. 2.9mol/L)
•    1-Hydroxy-2-pyridinethione sodium salt, 2-Mercaptopyridine-1-oxide sodium salt, 2-Pyridinethiol-1-oxide sodium salt, Pyrithione sodium salt
•    1-Hydroxy-2-pyridinethione sodium salt 2-Mercaptopyridine-1-oxide sodium salt 2-Pyridinethiol-1-oxide sodium salt Pyrithione sodium salt 2-Mercaptopyridine N-Oxide Sodium Salt N-Hydroxypyridinethione Sodium Salt Sodi
•    SPT (Sodium Pyrithione) 40% Solution
•    sodium 1-oxido-2-pyridin-1-iumthiol
•    (2-pyridylthio)-sodiun-oxide
•    2-pyridinethiol,n-oxide,sodiumsalt
•    thione(reagent)
•    2-(Sodiothio)pyridine-1-oxide
•    2-Sodiothiopyridine 1-oxide
•    UT900000
•    2-Pyridinothiol-1-oxide sodiumsalt
•    2-Mercaptopyridine N-Oxide Sodium Salt (40% in Water, ca. 3.3mol/L)
•    2- Mercaptopyridine N-Oxide Spdium Salt
•    2-Mercaptopyridine N-oxide sodium salt,1-Hydroxy-2-pyridinethione sodium salt, 2-Mercaptopyridine-1-oxide sodium salt, 2-Pyridinethiol-1-oxide sodium salt, Pyrithione sodium salt
•    2-Mercaptopyridine N-oxide, sodium salt, Sodium omadine
•    Sodium pyridine-2-thiolate N-oxide
•    Sodium pyridine-2-thiolate N-oxide, 40% aqueous solution
•    SodiuM 2-pyridinethiol-1-oxide (NaPT)
•    2-Mercaptopyridie N-oxide sodiuM salt

3811-73-2
Sodium Omadine
Sodium pyrithione
Sodium (2-pyridylthio)-N-oxide
Pyrithione sodium salt
2-Pyridinethiol-1-oxide sodium salt
2-Mercaptopyridine N-oxide sodium salt
PYRITHIONE SODIUM
Omadine sodium
UNII-6L3991491R
2-Mercaptopyridinen-oxide sodiumsalt
2-Mercaptopyridine N-oxide (sodium)
MFCD01941547
1-Hydroxy-2-pyridinethione sodium salt
6L3991491R
2-Pyridinethiol, 1-oxide, sodium salt (1:1)
2-Mercaptopyridine N-oxide sodium salt anhydrous
2-Pyridinethiol 1-Oxide Sodium Salt
Sodium 2-sulfidopyridine 1-oxide
Sodium-2-pyridinethiol-1-oxide
Sodium omadine (VAN)
Sodium pyrithione (VAN)
Prestwick_78
NSC 4483
EINECS 223-296-5
Sodium, (2-pyridinylthio)-, N-oxide
2-Pyridinethiol, N-oxide, sodium salt
2-Mercaptopyridine-N-oxide, sodium salt
C5H4NNaOS
(1-Hydroxy-2-pyridinethione), sodium salt
AI3-22596
sodium (1-oxidopyridin-1-ium-2-yl)sulfanide
DSSTox_CID_22390
DSSTox_RID_80011
DSSTox_GSID_42390
SCHEMBL3101261
CHEMBL2364542
DTXSID3042390
AMY3577
2-Mercaptopyridine n-oxide sodium
N-Hydroxypyridinethione Sodium Salt
EBD41219
STR00395
Tox21_300128
AKOS000121187
sodium1-oxidopyridin-1-ium-2-thiolate
2-Mercaptopyridine-1-oxide sodium salt
AC-1079
HY-125785A
Pyridine-2-thiol 1-oxide, sodium salt
NCGC00254107-01
CAS-3811-73-2
CS-0129647
M0632
M2841
Sodium, (2-pyridylthio)-, N-oxide (7CI)
2-Mercaptopyridine N-oxide sodium salt, 95%
EC 223-296-5
2-Mercaptopyridine N-oxide sodium salt, >=96%
(1-Hydroxy-2-pyridinethione), sodium salt, tech.
2-Mercaptopyridine N-oxide sodium salt, anhydrous
W-106499
Q27265081
2-Mercaptopyridine N-oxide sodium salt, >=96.0% (NT)
Sodium pyridine-2-thiolate N-oxide, 40% aqueous solution
2-Mercaptopyridine N-oxide sodium salt solution, ~40% in H2O, very deep brown
Sodium-2-pyridinethiol-1-oxide; 2-Mercaptopyridine-N-oxide sodium salt; 2-Pyridinethiol-1-oxide sodium salt; N-Hydroxy-2-pyridinethione sodium salt

Metalworking fluids are fertile breeding grounds for microorganisms, particularly bacteria and fungi.
Their unchecked growth causes fluids to deteriorate and degrades the fluid performance; this in turn causes damage to the work piece, cutting tools and fluid handling systems.
Growth of microorganisms in fluids can also affect workers by causing foul odors, skin irritation and allergic reactions.
These problems can be reduced or eliminated through the proper use of an antimicrobial agent.

SODIUM OMADINE is a proprietary blend based on the antimicrobial active, sodiumpyrithione (CAS # 3811-73-2) a fungicidal product with a successful history of use by the metalworking industry.
SODIUM OMADINE exhibits increased efficacy against a wide variety of microorganisms found in metalworking fluid systems.
In addition to its anticipated antifungal performance, SODIUM OMADINE Antimicrobial also exhibits antibacterial efficacy

Sodium omadine
Agent Name
Sodium omadine

CAS Number
15922-78-8; 3811-73-2

Formula
C5-H5-N-O-S.Na

Synonyms
15922-78-8: Pyrithione sodium; 1-Hydroxy-2(1H)-pyridinethionato sodium; 1-Hydroxy-2(1H)-pyridinethione, sodium salt; AL02725; Omacide 24; Omadine-sodium; SQ 3277; Sel de sodium de 1-hydroxy-2 (1H)-pyridinethione [French]; Sodium 1-hydroxypyridine-2-thione; Sodium 2-pyridinethiol-1-oxide; Sodium Omadine; Sodium pyrithione; 2(1H)-Pyridinethione, 1-hydroxy-, sodium; [ChemIDplus] 3811-73-2: 2-Pyridinethiol, 1-oxide, sodium salt; Sodium (2-pyridylthio)-N-oxide; Sodium pyrithione; (1-Hydroxy-2-pyridinethione), sodium salt; (1-Hydroxy-2-pyridinethione), sodium salt, tech.; 1-Oxo-2-pyridinethiol sodium salt; 2-Mercaptopyridine 1-oxide sodium salt; 2-Mercaptopyridine oxide sodium salt; 2-Mercaptopyridine-N-oxide sodium salt; 2-Pyridinethiol N-oxide sodium salt; 2-Pyridinethiol-1-oxide sodium salt; Omadine sodium; Sodium (2-pyridylthio)-N-oxide; Sodium 2-mercaptopyridine 1-oxide; Sodium 2-pyridinethiol 1-oxide; Sodium 2-pyridinethiol N-oxide; Sodium 2-pyridinethiolate 1-oxide; Sodium omadine (VAN);
Sodium, (2-pyridinylthio)-, N-oxide; Thione (reagent); [ChemIDplus]

Category
Biocides/Disinfectants

Description
Technical product is off-white solid; Formulated as liquid soluble concentrates; [Reference #1] 3811-73-2: Hygroscopic crystalline powder with a stench; [Alfa Aesar MSDS]

Sources/Uses
Used as biocide (controls slime forming bacteria and fungi) in aqueous functional fluids (metalworking, cutting, cooling, and lubricating), latex emulsions (adhesives, caulks, patching compounds, sealants, pastes, and grouts), aqueous fiber lubricants and inks, jet-printer inks, laundry rinse additives and detergents, carpet cleaners, analytical and diagnostic reagents; Also used as in-can preservative for water based mixtures used in making concrete (not covered in this RED); [Reference #1]

Comments
A mixture of two tautomers: 1-hydroxy-2(1H)-pyridinethione, sodium salt (15922-78-8) and 2-pyridinethio-1-oxide, sodium salt (3811-73-2); Not a skin sensitizer in guinea pig or human studies; Minimum to marked hind-limb atrophy observed in 13-week gavage study of rats at highest tested dose of 8 mg/kg/day (LOEL of 2 mg/kg/day based on evidence of neurotoxicity); [Reference #1] 3811-73-2: A skin and strong eye irritant; Harmful by ingestion; [Alfa Aesar MSDS]

Melting point    70 to 73 °C (158 to 163 °F; 343 to 346 K)
Solubility in water    2.5 g L−1 at 20 °C
Solubility    Soluble: benzene, chloroform, dichloromethane, dimethylformamide, dimethylsulfoxide, ethyl acetate[1]
Slightly soluble: diethyl ether, ethanol, methyl tert-butyl ether, tetrahydrofuran[1]
Acidity (pKa)    −1.95, 4.6[2][3]

Hazards
R-phrases (outdated)    R20/21/22, R36/37/38, R63
S-phrases (outdated)    S22, S24/25, S26, S36/37
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
Pyrithione is the common name of an organosulfur compound with molecular formula C5H5NOS, chosen as an abbreviation of pyridinethione, and found in the Persian shallot.
It exists as a pair of tautomers, the major form being the thione 1-hydroxy-2(1H)-pyridinethione and the minor form being the thiol 2-mercaptopyridine N-oxide; it crystallises in the thione form.[5] It is usually prepared from either 2-bromopyridine,[1] 2-chloropyridine,[6][7] or 2-chloropyridine N-oxide,[8] and is commercially available as both the neutral compound and its sodium salt.[1] It is used to prepare zinc pyrithione,[9][10] which is used primarily to treat dandruff and seborrhoeic dermatitis in medicated shampoos,[11][12] though is also an anti-fouling agent in paints

Synonym: sodium omadine, sodium pyrithione, sodium 2-pyridylthio-n-oxide, pyrithione sodium salt, thione reagent, 2-pyridinethiol-1-oxide sodium salt, 2-mercaptopyridine n-oxide sodium salt, omadine sodium, sodium-2-pyridinethiol-1-oxide, sodium omadine van

2-Pyridinethiol, 1-oxide, sodium salt
Pyridine-2-thiol 1-oxide, sodium salt
EC Inventory
pyridine-2-thiol 1-oxide, sodium salt
Pyridine-2-thiol 1-oxide, sodium salt (Sodium pyrithione)

Pyrithione sodium
Cosmetic Products Regulation, Annex II – Prohibited Substances

Translated names
1-ossido di piridin-2-tiolo, sale di sodio (Piritione di sodio) (it)
1-oxyde de pyridine-2-thiol, sel de sodium (pyrithione de sodium) (fr)
1-Óxido de piridina-2-tiol, sal de sódio (piritiona-sódio) (pt)
2-pyridin-tiol-1-oxid, natriumsalt (Natriumpyrition) (sv)
Piridin-2-tijol 1-ossidu, melħ tas-sodju (Pirition tas-sodju) (mt)
Piridin-2-tiol 1-oksid, natrijeva sol (natrijev pirition) (hr)
Piridin-2-tiol 1-oksid, natrijeva sol (natrijev pirition) (sl)
Piridin-2-tiol 1-oxid, sare de sodiu (Piritionă de sodiu) (ro)
Piridin-2-tiol-1-oxid, nátriumsó (Nátrium-pirition) (hu)
Piridin-2-tiolio 1-oksidas, natrio druska (Natrio piritionas) (lt)
Piridina-2-tiol-1-óxido, sal de sodio (piritiona sódica) (es)
Piridīn-2-tiol-1-oksīda nātrija sāls (nātrija piritions) (lv)
Pyridiini-2-tioli-1-oksidi, natriumsuola (natriumpyritioni) (fi)
pyridin-2-thiol-1-oxid, natriumsalt (natriumpyrithion) (da)
Pyridin-2-thiol-1-oxid, Natriumsalz (Natrium-Pyrithion) (de)
pyridin-2-thiol-1-oxid, sodná sůl (pyrithion sodný) (cs)
Pyridine-2-thiol 1-oxide, sodium salt (Sodium pyrithione) (no)
Pyridine-2-thiol-1-oxide, natriumzout (natriumpyrithion) (nl)
Püridiin-2-tiool-1-oksiidi naatriumisool (naatriumpüritioon) (et)
sodná soľ pyridín-2-tiol-1-oxidu (pyritión-nátrium) (sk)
Sól sodowa 1-tlenku pirydyno-2-tiolu (pirytion sodu) (pl)
Άλας του πυριδινο-2-θειολ 1-οξειδίου με νάτριο (Sodium pyrithione) (el)
Натриева сол на пиридин-2-тиол-1-оксид (натриев пиритион) (bg)

CAS names
2-Pyridinethiol, 1-oxide, sodium salt (1:1)

IUPAC names
2-Mercaptopyridine N-oxide sodium salt
2-Mercaptopyridine N-Oxide Sodium Salt Anhydrous
2-Pyridinethiol, 1-oxide, sodium salt
2-Pyridinthiol-1-oxid, Na-Salz
bis(1-hydroxy-2(1H)-pyridinethionato-O,S)-(T-4) sodium
Pyridine-2-thiol 1-oxide, sodium salt
pyridine-2-thiol 1-oxide, sodium salt
Pyridine-2-thiol-1-oxide, sodium salt
sodium (1-oxo-1lambda5-pyridin-2-yl)sulfanide
Sodium (2-Sodium 2-pyridenethio-1-oxide)
Sodium 1-oxidopyridine-2-thione
Sodium pyrithione
sodium-1-oxidopyridine-2-thione
Sodium-2-pyridinethiol-1-oxide
sodium;1-oxidopyridine-2-thione
Triadine 10

DIRECTIONS FOR USE: It is a violation of federal law to use this product in a manner inconsistent with its labeling.
Do not apply SODIUM PYRITHIONE in a way that will contact workers or other persons.
Do not use for applications involving direct or indirect food/drinking water contact.

For contaminated Fluid Systems:
AQUEOUS BASED FLUIDS SUCH AS METALWORKING, CUTTING, COOLING AND LUBRICATING FLUIDS: To inhibit bacterial and fungal growth add an initial dose of 125 ppm up to 1250 ppm of this product, or 0.125 lbs. up to 1.25 lbs. of this product per 1,000 lbs. of solution, to the solution by pouring from the container and subsequent maintenance doses of 125 ppm up to 1250 ppm, or 0.125 lbs. up to 1.25 lbs. SODIUM PYRITHIONE per 1,000 lbs. of solution, every 7- 10 days or as needed.
This product can be used at fluid to water ratios of 1: 10 to 1: 100.
This product may be added to the fluid at the time it is prepared (diluted) or to the reservoir (sump) containing the fluid after it is put into use.

If SODIUM PYRITHIONE is added to the reservoir, the fluid should be circulated after addition to ensure mixing.
Contaminated fluid systems should be cleaned prior to the initial addition of this product.
Drain the system, clean with a cleaner designed for this purpose, rinse with water and refill with fresh fluid containing this product , 125 ppm up to 1250 ppm.
Frequent checks (at least once a week) of the bacterial and fungal population in the system should be made using standard microbiological plate count procedures or any of the commercial “dip- stick” type devices.
When the bacterial count reaches 107 and/ or the fungal count reaches 103 organisms per ml, add additional SODIUM PYRITHIONE according to the above directions.
If this does not reduce the bacterial and/ or fungal count below the above value in 12- 24 hours, the fluid should be discarded and replaced after cleaning the system.
Add SODIUM PYRITHIONE to the fresh fluid according to the above directions.
When adding fresh, diluted fluid to compensate for dragout or other losses, add this product to make- up fluid according to the above directions.

TO INHIBIT THE GROWTH OF AND FUNGI IN METALWORKING, CUTTING, COOLING AND LUBRICATING FLUID CONCENTRATES: Add an amount that will give from 188ppm up to a 1250 ppm solution, or 0.188 lbs. up to 1.25 lbs. of product per 1,000 lbs. of solution.
The amount required in the concentrate will depend on the end use dilution.

For example: If the desired level of SODIUM PYRITHIONE is 1250 ppm and the end use dilution of the fluid is 5%, then a 2.5% concentration of SODIUM PYRITHIONE is required in the concentrate (1250 ppm/ 0. 05= 25,000 ppm or 2.5%).

FOR THE IN-CAN PRESERVATION OF LATEX EMULSIONS USED IN ADHESIVES, CAULKS, PATCHING COMPOUNDS, SEALANTS, PASTES AND GROUTS: To inhibit bacterial growth in latex emulsions for a period of up to 1 year, a dosage of up to 1000 ppm of this product, or 1 lb. of this product per 1,000 lbs. of emulsion, is recommended.

Product may be added at any time during the formulation procedure by pouring from the container.

IN AQUEOUS SYNTHETIC FIBER LUBRICANTS (SPIN FINISHES): To inhibit the growth of bacteria and the formation of bacterial slime in synthetic fiber lubricants (spin finishes) for periods of 2- 4 weeks during use, add 1250 ppm, or 1.25 lbs. per 1,000 lbs. of lubricant, of this product to the diluted lubricant.
SODIUM PYRITHIONE may be used in lubricant solutions containing 5- 10% lubricant concentrate (water to lubricant ratios of 20- 1 to 10- 1).

This product should be added by pouring from the container to the diluted lubricant in the dilution tank.

IN AQUEOUS BASED INKS: To inhibit the growth of bacteria and fungi in inks such as aqueous based inks, printing solutions, pigment slurries or press cake, add up to 1250 ppm, or 1.25 lbs. of this product per 1,000 lbs. of solution, of this product. While the inks are in use, a concentration of 0.125% w/ w of this product is necessary.
The amount of SODIUM PYRITHIONE to be added at the time of manufacture of the ink to obtain the above concentrations, at the time of use, will vary with the shelf- life of the ink.

To inhibit the growth of bacteria in neutral or slightly acidic aqueous based jet- printer inks for periods of up to 4 weeks while the inks are in use, add 0.75% w/ w SODIUM PYRITHIONE to the ink at the time of manufacture.

To avoid decomposition of this product during shelf- life of the ink, airtight packaging must be used.
In all cases, SODIUM PYRITHIONE may be added to the ink at any point in the manufacturing process by pouring from the container.

FOR THE DRY FILM PRESERVATION OF NATURAL AND SYNTHETIC ADHESIVES, LATEXES, URETHANE FOAMS, CELLULOSICS, CAULKS, PATCHING COMPOUNDS, SEALANTS, ARCHITECTURAL PAINTS, INDUSTRIAL PAINTS AND COATINGS (Including wood coatings), PASTES AND GROUTS: Addition of 2100 to 12500 ppm, or 2.1 lbs. to 12.5 lbs. of this product per 1000 lbs. of formulation, of this product can inhibit microbial growth (bacteria and fungi) in the dry film of these products.

SODIUM PYRITHIONE can be added at any time during the formulation procedure.
For example, sheet vinyl adhesives used in the installation of vinyl flooring can be preserved by the addition of 5200 ppm of this product, or 5.2 lbs. per 1000 lbs. of adhesive.

FOR THE IN- CAN PRESERVATION OF LAUNDRY RINSE ADDITIVES, LAUNDRY DETERGENTS, CARPET CLEANERS, SURFACE CLEANERS, FLOOR CLEANERS: To inhibit the growth of bacteria and fungi in these products for periods of up to one year, add 0.16% w/ w, or 1600 ppm or 1.6 lbs. of this product per 1000 lbs. of formulation.
SODIUM PYRITHIONE can be added at any time during the formulation procedure.

FOR THE IN- CAN PRESERVATION OF WATER BASED CHEMICAL OR MINERAL ADDMIXTURES THAT ARE USED IN CONCRETE: Addition of up to 1000 ppm of SODIUM PYRITHIONE can inhibit microbial growth (bacteria and fungi) in add mixtures.

Add mixtures can be preserved by addition of 1000 ppm of this product, or 1.0 lb. of this product per 1000 lbs. of add mixture.

FOR THE PRESERVATION OF AQUEOUS ANALYTICAL AND DIAGNOSTIC REAGENTS USED IN CHEMICAL AND CLINICAL ANALYSIS: Addition of up to 1250 ppm of this product can inhibit the growth of bacteria and fungi in aqueous analytical and diagnostic reagents, or 1.25 lbs. of this product per 1000 lbs. of reagent.

TO INHIBIT THE GROWTH OF FUNGI IN GYPSUM WALLBOARD: Addition of 1000 to 9600 ppm of this product, or 1.0 lb to 9.6 lbs of product per 1000 lbs of the formulation (i.e., wet slurry), will inhibit the growth of fungi.
SODIUM PYRITHIONE can be added at any time during the formulation procedure.

For example, to control the growth of fungi in Gypsum & Dry Wall add a minimum of 1000 ppm of this product, or 1.0 lb. of SODIUM PYRITHIONE per 1000 lbs of formulation.

To Control The Growth Of Fungi In Carrageenan Based Gels Used To Produce Solid Air Fresheners.
Add 0.03 – 0.1% SODIUM PYRITHIONE (0.03 – 0.1 lb./100 lbs. of formulation).
Add SODIUM PYRITHIONE into the gel formulation prior to cooling.
To Inhibit the Growth of Bacteria and Fungi In Dry Wall and Gypsum, Pearlite, Plaster-Like, Mineral Based, or Cellulose Derived Building Materials Used In the Manufacture of Ceilings, Ceiling Tile, Walls and Partitions: Addition of up to 9600 ppm of SODIUM PYRITHIONE (9.6 lbs. of product per 1000 lbs. of the formulation, i.e., wet slurry) will inhibit the growth of bacterial and fungi.
SODIUM PYRITHIONE can be added at any time during the formulation procedure.

Alternatively SODIUM PYRITHIONE may be added to latex or other types of coating systems routinely applied to the surfaces of walls, ceiling tiles, partitions, etc. at the same dosage as above.

LEATHER: SODIUM PYRITHIONE is used at treatment rates of 0.02% to 1.0%, based on the weight of the leather stock, to prevent the bacterial or fungal degradation of hides and skins.

Application level is dependent on the type of hide or leather to be protected, the length of protection desired and the presence of other constituents in the processing formula.
The optimum addition should be determined by trial for each individual application.
For soaking raw hides SODIUM PYRITHIONE should be added to the water to be used for soaking.
For treating hides cured with dry salt, this product should be applied to the hides or should be mixed with the salt before it is applied to the hides.
SODIUM PYRITHIONE can be used for the protection of wet leather stock such as pickled, chrome, chrome alternative, metal free, and vegetable tanned leathers from mold and mildew during in-tannery wet processing and for the protection of wet-blue during long storage and transportation times.
Treatment rates should be calculated based on the wet white weight or wet blue weight, and compatibility with chrome solutions or other treatment chemicals should be confirmed prior to trial.

Mold-resistant gypsum panel and method of making same
Jun 28, 2002 – United States Gypsum Company
A mold-resistant gypsum panel includes a core of an interlocking matrix of calcium sulfate dihydrate crystals, a facing material on at least one side of the panel and a salt of pyrithione dispersed through both the core and the facing materials. A method of making a mold-resistant gypsum product is also provided. A slurry of calcined gypsum, water and a water-soluble pyrithione salt is formed, then deposited on a sheet of facing material. The slurry on the facing material is shaped into a panel and maintained under conditions sufficient for the calcined gypsum to react with the water to form a core comprising an interlocking matrix of set gypsum crystals. Heating of the panel causes evaporation of the water that did not react with the calcined gypsum.

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Skip to: Description  ·  Claims  ·  References Cited  · Patent History  ·  Patent History
Description
BACKGROUND OF THE INVENTION
The present invention relates to a product and process for making gypsum panels. More particularly, the present invention relates to a gypsum panel with improved resistance to mold (also referred to as mildew).

Gypsum panels are well known building products which have been used for years. They are used primarily as an interior wall and ceiling product, but also to a certain extent as an exterior product. A slurry including calcium sulfate hemihydrate and water is used to form the core, and continuously deposited on a paper cover sheet moving beneath a mixer. A second paper cover sheet is applied thereover and the resultant assembly is formed into the shape of a panel. Calcium sulfate hemihydrate reacts with sufficient water to convert the hemihydrate into a matrix of interlocking calcium sulfate dihydrate crystals, causing it to set and to become firm. The continuous strip thus formed is conveyed on a belt until the calcined gypsum is set, and the strip is thereafter cut to form boards of desired length, which boards are conveyed through a drying kiln to remove excess moisture.

Fungi, such as mold, may grow in environments where four key elements are present. There must be mold spores present, nutrients for the fungi to metabolize and water. Temperature is also a critical parameter for fungi growth, but numerous mold species thrive at the temperatures required for human habitation so this is often considered a given for mold growth in buildings. Although various environments provide different amounts of each of these elements, water vapor and spores are constantly in the air around us. The spores require sufficient nutrients to be able to grow if they settle on a substrate where moisture is present.

While various nutrients are generally present in dust particles in surrounding air, starches also provide sufficient nutrition for mold growth and are often present in both the cover materials and the gypsum core of gypsum panels. In gypsum panels, starch is frequently used for a number of purposes. It is used to promote adhesion between the core and the covering material. The pressed paper commonly used to cover the panels is a source of starch and the cellulosic fibers provide nutrition for mold growth. Sugar is used to coat particles of calcium sulfate dihydrate, often used as a set accelerator in the calcined gypsum slurry. Other starches are also used to modify properties of the set gypsum composition. Thus, where gypsum board panels become wet and do not dry out readily, the use of starches in covering and core materials provides a medium suitable for possible growth of mold spores. Gypsum board panels, even if not specially treated to make them mold-resistant, still will not usually experience mold growth problems in interior building applications or in other applications where they are likely to be kept dry or to dry out readily after becoming wet.

However, there are some applications where gypsum board is desirable for its fire resistance, but where it may become wet and not readily dry out. In high-rise buildings, for example, elevator shafts are built before the building is enclosed. Thick gypsum panels, such as Sheetrock® brand Gypsum Liner Panels by USG Corp., Chicago, Ill., are used to line the elevator shafts to provide fire resistance. The shaft wall may be exposed to rain during building construction, and may not have the opportunity to dry thoroughly before the building is closed in. Panels used in this environment, and other environments where mold growth is possible, are subject to improvement by increasing the resistance of the panels to the growth of molds.

Gypsum panels are known that have utilized pressed paper coverings treated with a fungicide. Treated paper is ineffective to control mold growth for a number of reasons. Many fungicides do not retain their efficacy through the process of drying the panels in a kiln due to the high temperatures. Water used in the manufacturing of gypsum panels may contain mold spores, providing a source of spores from both the air and the set gypsum. Per environmental regulations, there is a limit to the concentration of fungicide that can be present on the surface of the paper, and it appears that that concentration is not sufficient to protect both the paper and the set gypsum core.

Attempts have been made to add fungicides to the gypsum slurry, resulting in different problems. Water-soluble fungicides tend to migrate with the water during the drying process, depositing on the covering when the water evaporates. In addition to leaving the core unprotected, the paper covering may have a concentration of fungicide that is too high to meet environmental regulations. Fungicides that are insoluble are difficult to disperse in the aqueous slurry and provide no protection for the covering material. Chemicals added directly to the gypsum slurry can also have detrimental effects on the properties of the set gypsum product. When boric acid, a known fungicide, was added to a slurry in sufficient quantity to greatly inhibit mold growth, the panels were so brittle that they cracked and chipped as they moved along the rollers from the kiln.

Another technique of protecting a gypsum board is using a two-step process of covering a fungicide-containing core slurry with a treated face paper. In addition to many of the problems discussed above, use of a two-step process is more expensive than a single step process. Thus, although many fungicides are well known, this particular application poses unique problems in finding a fungicide that inhibits mold growth in both the covering and the core of gypsum board panels in a cost effective manner.

Pyrithione salts are well-known antimicrobial additives for coating applications. They are available commercially as sodium OMADINE® or zinc OMADINE, manufactured by Arch Chemicals, Inc. of Norwalk, Conn., or they can be made according to the process of U.S. Pat. No. 3,159,640, herein incorporated by reference. The prior art teaches only that these salts are useful in their wet state as preservatives or as short-term antimicrobial agents in dry, thin-film applications such as paints, adhesives, caulks and sealants. U.S. Pat. No. 5,939,203 discloses that joint compounds and patching compounds are suitable base media for use with pyrithione salts in coating compositions. Joint or patching compounds are thinly spread over joints between or imperfections in gypsum board panels, forming a thin film. The use of sodium pyrithione in these compounds would act as a wet state preservative for ready mixed products and would inhibit microbial growth on the dry film of the product.

SUMMARY OF THE INVENTION
In one aspect, the present invention features a gypsum panel having mold resistance in both the facing material and the gypsum core without separately treating them with antimicrobial agents.

More specifically, the present invention provides a mold-resistant gypsum panel that includes a core of at least ⅛ inch thickness of an interlocking matrix of calcium sulfate dihydrate crystals, a facing material on at least one side of the panel and having a salt of pyrithione dispersed through both the core and the facing material.

Another aspect of the present invention is a method of making a mold-resistant gypsum product. A slurry of calcined gypsum, water in excess of the amount needed to hydrate all of the calcined gypsum to form calcium sulfate dihydrate and a water soluble pyrithione salt is formed, then deposited on a sheet of facing material. The slurry on the facing material is shaped into a panel and maintained under conditions sufficient for the calcined gypsum to react with a portion of the water to form a core comprising an interlocking matrix of set gypsum crystals. Heating of the panel cause evaporation of the water that did not react with the calcined gypsum. The product of this process is another aspect of this invention.

The gypsum panel of this invention is advantageous for use in areas, such as elevator shaft walls, where there is potential for the gypsum panels to become wet. Use of pyrithione salts provides mold-resistance not only to the surface of the panels with which it is made, but also reduces mold growth throughout the thickness of the panel.

Addition of pyrithione salt to the gypsum slurry also serves to protect both the set core and the facing material in a single step. During setting and drying, a portion of the salt migrates from the core to the facing. Surprisingly, a portion of the fungicide is retained in the core even when water in excess of that required for hydration moves to the panel surface and evaporates during drying. Thus the step of adding pyrithione salts imparts an improved mold resistance throughout the thickness of the panel.

DETAILED DESCRIPTION OF THE INVENTION
It has now been surprisingly found that when soluble salts of pyrithione are added to a calcined gypsum slurry, a portion of the pyrithione compound remains in the core, while a portion migrates to the facing material, providing protection to both the facing material and the gypsum core.

Any water-soluble salt of pyrithione having antimicrobial properties is useful in the present gypsum panel. Pyrithione is known by several names, including 2 mercaptopyridine-N-oxide; 2-pyridinethiol-1-oxide (CAS Registry No. 1121-31-9); 1-hydroxypyridine-2-thione and 1 hydroxy-2(1H)-pyridinethione (CAS Registry No. 1121-30-8). The sodium derivative (C5H4NOSNa), known as sodium pyrithione (CAS Registry No. 3811-73-2), is one embodiment of this salt that is particularly useful. Pyrithione salts are commercially available from Arch Chemicals, Inc. of Norwalk, Conn., such as Sodium OMADINE or Zinc OMADINE.

Useful pyrithione salts are very soluble in water. Where solubility is measured on a weight percent basis in water at 77° F. (25° C.) and at pH of 7, the solubility of the pyrithione salt is sufficient to create a concentration of dissolved salt in the water of at least 0.1% of the resultant solution. Sodium OMADINE, a preferred pyrithione, has a solubility of about 53%. Zinc OMADINE, which shows no migration of the fungicide into the facing material, has a solubility of about 0.0015%. Preferably, the solubility of the pyrithione salt is from about 0.1% to about 75%, more preferably from about 5% to about 60% or even more preferably from about 30% to about 55%. Other pyrithione salts with a solubility above 0.1% are expected to be suitable for use with the present gypsum panel.

Solubility of a fungicide is not a guarantee that it will remain completely dispersed in the slurry or migrate into the facing material along with the water that seeps out of the core and through the facing material during vaporization, while, most surprisingly, an effective portion of the pyrithione salt does not migrate and appears to become anchored in the core by some unknown mechanism. Molecules that are very soluble and highly mobile are expected to move with the water as it evaporates and be left on the surface of the gypsum board panel. A species of the fungicide highly reactive with the calcium sulfate of the gypsum or any additives used has the potential to form an insoluble species that does not migrate or form a precipitate that settles out. The ability of the fungicide to migrate, its reactivity with components of the slurry and the solubility act together to determine whether a fungicide is suitable for use with this invention. Pyrithione salts having the requisite solubility are useful in this invention.

It is particularly surprising that the pyrithione salt protects both the gypsum core and the facing material. While not wishing to be bound by theory, it is believed that a portion of the pyrithione salt migrates into the facing paper, while a portion becomes anchored in the gypsum core. Perhaps the Ca++ ion slowly displaces the sodium ion to react with the pyrithione ion, forming a less mobile or less soluble species. It is also possible that as the matrix of calcium sulfate dihydrate molecules begins to form, the larger pyrithione ions become less mobile and become trapped in the interstices of the matrix due to their size. Either of these theories, both of them or even another theory entirely could be responsible for the observed distribution of the fungicide throughout the core and the facing material. Regardless of the actual mechanism, fungicides that display this behavior are useful in the gypsum board of this invention.

The pyrithione salt is added to the gypsum slurry in any effective amount. In one embodiment, at least 100 parts of salt per million parts of calcined gypsum on a weight basis are used. All concentrations of the pyrithione salt are calculated as the equivalent amount of the sodium derivative and based upon the weight of the calcined gypsum. Preferred sodium pyrithione concentrations include at least 100 ppm, more preferably from about 100 ppm to about 600 ppm, still more preferably from about 100 ppm to about 400 ppm, even more preferably from about 200 ppm to about 400 ppm and most preferably from about 200 ppm to about 300 ppm.

Whereas a gypsum board panel has a plurality of sides or faces, it is not necessary that all faces be covered with a facing material. In some circumstances, one or more sides are optionally left unfaced. Panels intended for use with this invention include at least one side with a facing material that is susceptible to supporting fungus growth. The facing material need not contain a nutrient, but will be more susceptible to supporting fungus growth if it already contains a nutrient.

A “nutrient-containing” facing material is one that includes any nutrients capable of feeding fungus growth to a detectable level. Facing materials containing paper, pulp or any starch are the most common. The nutrient is suitably present in the finished gypsum panel, and need not be an inherent component of the facing material alone. Starches, for example, are frequently added to the core slurry to promote adhesion between the core and facing paper. The water-soluble starch is carried into the paper as excess water is driven from the core and acts as an adhesive. Presence of the starch in the facing material after drying is sufficient to feed fungal growth, and thus would be a “nutrient-containing” facing for the purposes of this invention. Pressed paper is a preferred facing material due to its common availability and low cost. Facing paper is optionally bleached or unbleached. The paper comprises one or more layers or plies. It is contemplated that, where multiple plies are used, it is suitable for one or more plies to differ from each other in one or more respects. It is also contemplated that facing material other than paper be used in this invention.

The slurry used to make the gypsum core comprises water and calcined gypsum. Any calcined gypsum comprising calcium sulfate hemihydrate, calcium sulfate anhydrite or both is useful in this slurry. Calcium sulfate hemihydrate can produce at least two crystal forms, the alpha and beta forms. Beta calcium sulfate hemihydrate is commonly used in gypsum board panels, but is also contemplated that panels made of alpha calcium sulfate hemihydrate are also useful in this invention. The fungicide, as well as other additives discussed below, are added to the slurry.

Water is present in any amount useful to make gypsum board panels. Sufficient water is added to the dry components to make a flowable slurry. A suitable amount of water exceeds the amount needed to hydrate all of the calcined gypsum to form calcium sulfate dihydrate. The exact amount of water is determined, at least in part, by the application with which the product will be used, the amount and type of additives used and whether the alpha or beta form of the hemihydrate is used. A water-to-stucco ratio is calculated based on the weight of water compared to the weight of the dry calcined gypsum. Preferred ratios range from about 0.6:1 to about 1:1.

In some embodiments of the invention, additives are included in the gypsum slurry to modify one or more properties of the final product. Concentrations are reported in amounts per 1000 square feet of finished board panels (“MSF”). Starches or defoamers are used in amounts from about 6 to about 20 lbs./MSF to increase the density and strengthen the product. Set retarders (up to about 2 lb./MSF) or accelerators (Up to about 35 lb./MSF) are added to modify the rate at which the hydration reactions take place. “CSA” is a set accelerator comprising 95% calcium sulfate dihydrate co-ground with 5% sugar and heated to 250° F. (121° C.) to caramelize the sugar. CSA is available from USG Corporation, Southard, Okla. Plant, and is made according to U.S. Pat. No. 3,573,947, herein incorporated by reference. Glass fibers are optionally added to the slurry in amounts of at least 9 lb./MSF. Up to 15 lb./MSF of paper fibers are also added to the slurry. Dispersants or surfactants are common additives to modify the viscosity or surface properties of the slurry. Naphthalene sulfonates are preferred dispersants, such DILOFLOW® from Geo Specialty Chemicals, Cleveland, Ohio. Preferably, a dispersant is added to the core slurry in amounts up to 16 lb./MSF. Wax emulsions, discussed in more detail below, are added to the gypsum slurry in amounts up to 20 gal./MSF to improve the water-resistency of the finished gypsum board panel. Pyrithione salts are useful in addition to other preservatives. There are no known adverse effects when pyrithione salts are used together with any other additives. It is therefore contemplated that pyrithione salts are useful when combined with any additives added to the gypsum core slurry to modify other properties of the set gypsum core.

In embodiments of the invention that employ a foaming agent to yield voids in the set gypsum-containing product to provide lighter weight, any of the conventional foaming agents known to be useful in preparing foamed set gypsum products can be employed. Many such foaming agents are well known and readily available commercially, e.g. from GEO Specialty Chemicals, Ambler, Pa. Foams and a preferred method for preparing foamed gypsum products are disclosed in U.S. Pat. No. 5,683,635, herein incorporated by reference.

A trimetaphosphate compound is added to the gypsum slurry in some embodiments to enhance the strength of the product and to reduce sag of the set gypsum. Preferably the concentration of the trimetaphosphate compound is from about 0.1% to about 2.0% based on the weight of the calcined gypsum. Gypsum compositions including trimeraphosphate compounds are disclosed in U.S. Pat. No. 6,342,284, herein incorporated by reference. Exemplary trimetaphosphate salts include sodium, potassium or lithium salts of trimelaphosphate, such as those available from Astaris, LLC., St. Louis, Mo.

In addition, the gypsum composition optionally can include a starch, such as a pregelatinized starch or an acid-modified starch. The inclusion of the pregelatinized starch increases the strength of the set and dried gypsum cast and minimizes or avoids the risk of paper delamination under conditions of increased moisture (e.g., with regard to elevated ratios of water to calcined gypsum). One of ordinary skill in the art will appreciate methods of pregelatinizing raw starch, such as, for example, cooking raw starch in water at temperatures of at least about 185° F. (85° C.) or other methods. Suitable examples of pregelatinized starch include, but are not limited to, PCF 1000 starch, commercially available from Lauhoff Grain Company and AMERIKOR 818 and HQM PREGEL starches, both commercially available from Archer Daniels Midland Company. If included, the pregelatinized starch is present in any suitable amount. For example, if included, the pregelatinized starch can be added to the mixture used to form the set gypsum composition such that it is present in an amount of from about 0.5% to about 10% percent by weight of the set gypsum composition.

A preferred embodiment of this invention comprises a water resistant gypsum board panel with mold resistance. Manufacture of water-resistant gypsum board panels, known as “green board” is well known in the art. One embodiment of a water-resistant gypsum board is taught in Camp, U.S. Pat. No. 2,432,963, herein incorporated by reference, wherein from about 5% by weight to about 15% of a wax-asphalt emulsion is added to the gypsum slurry. Paraffin wax is the preferred wax, and preferably has a melting point less than 165° F. (74° C.). It is present in a ratio of wax to asphalt of about 1:1 to about 1:10. A preferred asphalt has a ring-and-ball softening point that is not above 185° F. (85° C.). The emulsion of wax and asphalt is formed by dispersing the wax and asphalt using a dispersing agent, then is added to the gypsum slurry in any convenient way.

Another embodiment of the water-resistant gypsum board panel is taught in U.S. Pat. No. 6,010,596 to Song, herein incorporated by reference, wherein a wax emulsion is added to the core slurry.

The present gypsum panel exceeds ⅛ inch in thickness to avoid excessive breakage during manufacture. Preferably the gypsum panels are from about ⅜ inch (9.5 mm) to about 2 inches (51 mm), from about ¾ inch (19 mm) to about 1¼ inch (32 mm) or from about ½ inch (13 mm) to about 1 inch (25 mm) in thickness. The exact thickness of the panel depends upon the end use to which it will be put. Thicker panels are frequently used where high ratings for fire resistance are desired. Relatively thin panels are contemplated for use in areas of high humidity, such as a bathroom in a home. SHEETROCK brand Gypsum Liner Panels 1 inch thick are used to line elevator shafts in commercial buildings.

While individual panels can be made in a batch process, more usually gypsum board is made in a continuous process formed into a long panel and cut into panels of desired lengths. The formed facing material is obtained and put into place to receive the gypsum slurry. Preferably, the facing material is of a width to form a continuous length of panel that requires only two cuts to make a panel with the desired finished dimensions. Facing material is continuously fed to the board line.

The slurry is formed by mixing the dry components and the wet components together. Dry components of the slurry, the calcined gypsum and any dry additives, are blended together prior to entering the mixer. Water is measured directly into the mixer. Liquid additives are added to the water, and the mixer is activated for a short time to blend them. If purchased from Arch Chemicals, sodium OMADINE is sold in the form of a 40% suspension of sodium pyrithione in water, and is mixed with the slurry water. The dry components are added to the liquid in the mixer, and blended until the dry components are moistened.

The slurry is then mixed to achieve a homogeneous slurry. Usually, an aqueous foam is mixed into the slurry to control the density of the resultant core material. Such an aqueous foam is usually generated by high shear mixing of an appropriate foaming agent, water and air to prior to the introduction of the resultant foam into the slurry. The foam can be inserted into the slurry in the mixer, or preferably, into the slurry as it exits the mixer in a discharge conduit. See, for example, U.S. Pat. No. 5,683,635, herein incorporated by reference. In a gypsum board plant, frequently solids and liquids are continuously added to a mixer, while the resultant slurry is continuously discharged from the mixer, and has an average residence time in the mixer of less than 30 seconds.

The slurry is continuously dispensed through one or more outlets from the mixer through a discharge conduit and deposited onto a moving conveyor carrying the facing material and formed into a panel. Another paper cover sheet is optionally placed on top of the slurry, so that the slurry is sandwiched between two moving cover sheets which become the facings of the resultant gypsum panel. The thickness of the resultant board is controlled by a forming roll, and the edges of the board are formed by appropriate mechanical devices which continuously score, fold and glue the overlapping edges of the paper. Additional guides maintain thickness and width as the setting slurry travels on a moving belt. While the shape is maintained, the calcined gypsum is maintained under conditions sufficient (i.e. temperature of less than about 120° F.) to react with a portion of the water to set and form an interlocking matrix of gypsum crystals. The board panels are then cut, trimmed and passed to dryers to dry the set but still somewhat wet boards.

Preferably, a two-stage drying process is employed. The panels are first subjected to a high temperature kiln to rapidly heat up the board and begin to drive off excess water. The temperature of the kiln and the residence time of the board vary with the thickness of the panel. By way of example, a ½-inch board (12.7 mm) is preferably dried at temperatures in excess of 300° F. (149° C.) for approximately 20 to 50 minutes. As water at the surface evaporates, it is drawn by capillary action from the interior of the panel to replace the surface water. The relatively rapid water movement assists migration of the starch and the pyrithione salt into the paper. A second-stage oven has temperatures less than 150° F. (65.5° C.) to limit calcination of the board.

There is no standard test for the measurement of mold growth on the surface of gypsum board panels. As a result, the industry has adopted ASTM Standard D3273, herein incorporated by reference, originally developed for testing mold growth on paints and other interior surface coatings. This procedure, described briefly below, was used to evaluate the relative resistance of gypsum board panels to surface mold fungi and mildew growth in a severe interior environment. Performance of a panel at a certain rating in accordance with the Test Method D3273 does not imply any specific period of time for a fungal free panel. However, a better-rated product nearly always performs better in actual end use.

Samples of ½ inch (12.7 mm) gypsum board panel (Example 1) or 1 inch (25.4 mm) panel were measured and cut to three inches by eleven inches. The samples were hung vertically in an environmental chamber three inches above soil that had been impregnated with spores from several specific varieties of mold as specified in the rest procedure. Conditions in the chamber were maintained at 90° F. (32.2° C.) and 90% relative humidity for a total of four weeks. At the end of each week, random portions of the sample were studied under a microscope to determine the extent of mold growth on the surface of the sample. A rating was assigned to each sample at that time whereby a sample given a rating of ten had no mold growth and a sample that earned a rating of zero had essentially 100% mold coverage. After the microscopic analysis, the sample was returned to the environmental chamber.

A slight modification was made to the D3273 procedure to accommodate study of both the face paper and the gypsum core in Example 1. Samples were prepared to insure that the gypsum core was exposed to the environmental conditions at the cut edge, and that none of the edges was covered by the facing paper. When the samples were rated at weekly intervals, coverage of the gypsum core was determined by microscopic analysis, as well as study of the surface of the facing paper. Ratings were independently assigned to the gypsum core and the facing.

In the following examples, concentrations are reported on a weight basis of the dry components unless otherwise indicated. Concentrations of commercial products are measured on the basis of 1000 ft2 (“MSF”) of finished gypsum panel, and therefore change depending on the thickness of the board being produced.

EXAMPLE 1
Gypsum board panels were made in the laboratory having the composition shown in Table I.

TABLE I Composition of Laboratory Samples Component Control T1 Beta Calcium Sulfate 2.2 lbs. (1000 g.) 2.2 lbs. (1000 g.) Hemihydrate Water 47.3 fl. oz. (1400 ml) 47.3 fl. oz. (1400 ml) CSA 0.017 oz. (0.5 g.) 0.017 oz. (0.5 g.) Pregelatinized Starch 0.175 oz. (5 g.) 0.175 oz. (5 g.) Sodium trimetaphosphate 0.035 oz. (1 g.) 0.035 oz. (1 g.) Sodium Pyrithione 0 0.035 oz. (1 g.) (40% aqueous solution)
The beta hemihydrate is available as stucco from the Southard, Okla. plant of USG Corporation. Sodium trimetaphosphate is available from Astaris, LLC. St. Louis, Mo. The pregelatinized starch is PCF 1000 starch, commercially available from Lauhoff Grain Company, St. Louis, Mo. The sodium pyrithione used was Sodium OMADINE from Arch Chemicals, Inc., Norwalk, Conn., at a concentration of 400 ppm based on the weight of the calcined gypsum.

For each sample, the above ingredients were mixed together and allowed to soak for approximately 15 seconds. The slurry was mixed in a Waring blender for 15 seconds at medium speed, then poured onto a piece of an untreated, water resistant paper to a thickness of ½ inch. When the boards were set, they were dried in a 350° F. kiln for approximately 30 minutes, then at 110° F. overnight.

Both samples were subjected to the temperature and humidity of the environmental chamber according to ASTM Test Method D3273 described above. Ratings of each of the samples at each of the four weekly intervals is shown in Table II.

TABLE II Mold-Resistance Testing of Laboratory Samples Control Ti Time in Chamber Paper Core Paper Core 1 week, 2 days 0 0 10 10 2 weeks 0 0 8-9  9 3 weeks 0 0  9  9 4 weeks 0 0 10 10
Table II shows the test results of the microbial bioassay of the control and test sample, T1. The control sample was virtually continuously disfigured over the entire sample surface within 9 days of the start of the procedure, while both the paper surface and the gypsum core of the present composition have very little mold growth.

It is interesting to note that in the inventive sample, T1, about 10% of the paper and core had mold growth in weeks 2 and 3. However, by week 4, the mold was gone. It appears as though molds started to grow, but were killed by the fungicide over the course of the test. Some variations in results are also expected due to randomness in selection of areas for microscopic study.

EXAMPLE 2
Three samples of SHEETROCK® brand Gypsum Liner Panels were manufactured at a board plant substantially using the commercial process described above. An unmodified control sample was labeled B133, the composition of which is provided in Table III.

TABLE III Composition of B133 Control Sample Component B133 Beta Calcium Sulfate Hemihydrate 3400 lbs. Water 2278 lbs. CSA   12 lbs./1000 ft2 Starch, USG 95   8 lbs./1000 ft2 Chopped glass fibers   11 lbs./1000 ft2 Dispersant 11.5 lbs./1000 ft2 Foaming Agent 0.35 lbs./1 000 ft2 Wax Emulsion   18 gal./1000 ft2 Retarder  0.2 lbs./1000 ft2 Fungicide 0
A second sample, B134, included 18 gal./MSF of a wax emulsion and 3 lb./MSF boric acid added to the gypsum core. This second sample also used a fungicide treated paper. Paper pre-treated with METASOL TK-100® fungicide was purchased from Caraustar Industries of Austell, Ga. Wax emulsion (AQUALITE 70 from Bakor, Quebec, Calif.) was added to the test sample to improve the water repellency of the product. The dispersant was DILOFLOW from (GEO Specialty Chemicals, Cleveland, Ohio). The foaming agent was ALPHA FOAMER from (Stepan Chemicals, Ontario Calif.). A VERSENEX 80 (Dow Chemical, Midland, Mich.) retarder was used.

Sodium OMADINE was used in a third sample, B135, in place of the boric acid. B135 uses the same treated paper and wax emulsion, in the same concentration, as used in B134. The sodium OMADINE was used in a concentration of 2 lb./MSF, which is equivalent to 200 ppm. A summary of the additives to the B133 composition of Table III is provided in Table IV below:

TABLE IV Composition of Test Samples Sample B-133 B-134 B-135 Paper Untreated Treated Treated Wax Emulsion 0 18 gal/.MSF 18 gal./MSF Core Fungicide None Boric Acid Sodium OMADINE Fungicide conc. 0 3 lb./MSF 2 lb./MSF
All samples were subjected to the temperature and humidity of the environmental chamber according to ASTM Test Method D 3273 described above. Test samples were evaluated weekly for four weeks. Ratings of each of the samples at each of the four weekly intervals is shown in Table V.

TABLE V Mold-Resistance Testing of Commercial Samples Time in Chamber B133 B134 B135 1 week + 2 days 0 10 10  2 weeks 0 0 9 3 weeks 0 0 6 4 weeks 0 0 5
Table V shows the test results of the microbial bioassay of the samples B133, B134 and B135. The control sample was virtually continuously disfigured over the entire sample surface within 9 days of the start of the procedure, while the treated samples show inhibited mold growth on the treated paperfacing. Sample B134 using another fungicide, boric acid, maintained its mold resistance for the first nine days, then rapidly succumbed to mold growth and was continuously disfigured by the 14th day. The sodium pyrithione sample, B135, demonstrated improved mold resistance over the entire life of the test.

A comparison of samples B134 and B135 demonstrates the importance of pyrithione in this invention. The use of other fungicides, such as boric acid, does not afford the same degree of mold resistance provided by sodium pyrithione. Although pyrithione salts are the only fungicides known to be useful in this invention, it is contemplated that other fungicides may be found that are suitable for use in the gypsum core yet migrate into the facing paper of the finished gypsum board panel.

EXAMPLE 3
An additional test was conducted using concentrations of sodium pyrithione lower than Example 1 with untreated face paper.

The commercial samples were made according to the procedures of Example 2, but without pre-treating the facing paper with fungicide. Control Sample 2 was made according to the composition of the B133 composition described in Table III. Test sample T2 was made according to the same base composition, but with 2 lb./MSF of sodium OMADINE added, for a concentration of 200 ppm. Untreated paper was used and neither sample included a wax emulsion. Testing was carried out according to D 3273 described above. Results for the first two weeks of the test are summarized below.

TABLE V Mold-Resistance Testing of Commercial Samples Time in Chamber Control 2 T2 1 week 4 9-10 2 weeks 1 9-10
Even at concentrations of 200 ppm of sodium OMADINE in the T2 panels showed improved mold resistance compared to untreated panels. Even though it is difficult to compare results from different examples, it is interesting to note that after two weeks, T2, using untreated paper, provided about the same mold resistance as B135, which used fungicide-treated paper.

While a particular embodiment of the present mold resistant gypsum panel and method for making it has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.

Claims
1. A method of making a mold-resistant gypsum product comprising:

forming a slurry of calcined gypsum, water in excess of the amount needed to hydrate all of the calcined gypsum to form calcium sulfate dihydrate, and at least 100 ppm of a water soluble pyrithione salt calculated as the equivalent sodium salt and based on the weight of the calcined gypsum;
depositing the slurry on a sheet of facing material;
shaping the slurry on the facing material into a panel;
maintaining the slurry under conditions sufficient for the calcined gypsum to react with a portion of the water to form a core comprising an interlocking matrix of set gypsum crystals.
2. The method according to claim 1 wherein the pyrithione salt comprises sodium pyrithione.

3. The method according to claim 1 wherein the slurry further comprises at least one of a set accelerator, a set retarder, an aqueous foam, a dispersant, a surfactant and a starch.

4. The method according to claim 1, wherein the facing material contains no fungicide prior to said depositing of the slurry.

5. The method according to claim 1, wherein the facing material comprises paper.

6. The method according to claim 5 wherein said paper comprises a multi-ply pressed paper.

7. The method of claim 1 wherein said slurry comprises at least 0.6 parts by weight water per part of calcined gypsum.

8. The method of claim 1 wherein said pyrithione salt is present in the slurry at a concentration of at least 200 ppm, calculated as the equivalent sodium salt and based upon the weight of the calcined gypsum.

9. The method of claim 1 further comprising placing a second sheet of facing material over the slurry prior to said shaping step.

10. The method of claim 1 wherein said calcined gypsum comprises beta calcium sulfate hemihydrate.

11. The method according to claim 1 further comprising moving a portion of the water-soluble pyrithione salt from the core to the facing material in water.

12. The method of claim 1 further comprising heating the panel to cause evaporation of the water that did not react with the calcined calcined gypsum.

13. The method of claim 12 wherein said heating step comprises heating the gypsum board in a kiln at temperatures above 300° F.

14. The method of claim 1 further comprising adding a water resistant additive to the slurry.

15. A method of making a mold-resistant gypsum product comprising:

forming a slurry of calcined gypsum, water in excess of the amount needed to hydrate all of the calcined gypsum to form calcium sulfate dihydrate, a water resistant additive and a water soluble pyrithione salt;
depositing the slurry on a sheet of facing material;
shaping the slurry on the facing material into a panel; and
maintaining the slurry under conditions sufficient for the calcined gypsum to react with a portion of the water to form a core comprising an interlocking matrix of set gypsum crystals.
16. The method of claim 15 wherein said water resistant additive is a wax emulsion or a wax-asphalt emulsion.

17. A mold-resistant gypsum panel having a plurality of sides, comprising a core of at least ⅛ inch thickness of an interlocking matrix of calcium sulfate dihydrate crystals, a facing material on at least one side of said panel and having at least 100 ppm of a salt of pyrithione calculated as the equivalent sodium salt and based on the weight of the calcium sulfate dihydrate and being dispersed through said core and said facing material.

18. The panel of claim 17 wherein said facing material is paper.

19. The panel of claim 17 wherein said core has facing material on at least two sides.

20. The panel of claim 17 wherein said panel further comprises at least one of a set accelerator, a set retarder, a foaming agent, a dispersant, a surfactant and a starch.

21. The panel of claim 17 wherein said pyrithione salt is present in the slurry at a concentration of at least 200 ppm, calculated as the equivalent sodium salt and based upon the weight of the calcined calcium sulfate dihydrate.

22. The panel of claim 17 further comprising a water resistant additive.

23. The panel of claim 22 wherein said water resistant additive is a wax emulsion or a wax-asphalt emulsion.

24. The panel of claim 17 further comprising a second fungicide applied to said facing material.

25. A mold-resistant gypsum panel made according to a process comprising:

forming a slurry of calcined gypsum, water in excess of the amount needed to hydrate all of the calcined gypsum to form calcium sulfate dihydrate and at least 100 ppm of a water soluble pyrithione salt calculated as the equivalent sodium salt and based on the weight of the calcium sulfate dihydrate;
depositing the slurry on a sheet of facing material;
shaping the slurry on the facing material into a panel;
maintaining the slurry under conditions sufficient for the calcined gypsum to react with a portion of the water to form a core comprising an interlocking matrix of set gypsum crystals.

OTHER PRODUCTS OF ATAMAN KIMYA THAT MIGHT BE OF INTEREST:
AGROCHEMICALS

Milori blue
Pirrolidones
DMSO, Di Methyl Sulfoxide
Urea
Sodium Molibdate
Amonium Molibdate
Amines
Isopropylamine 70% & 99%
Antifoams
Denatonium benzoate powder, granules or diluted in different solvents
Acetamide
Dicyanamide
TIBP, Tri Iso Butyl Phosphate, CAS 78-38-6

CHEMICAL SYNTESIS

PTSA, Para Toluen Sulfonic Acid
HPA 50, Hypophosphorous Acid 50%
Acetic Anhydride
TNBT,  Tetra n-butyl Titanate

CONSTRUCTION CHEMICALS

MDEA, Methyl Diethanolamine
TIBP, Tri Iso Butyl Phosphate, CAS 78-38-6
TIPA 85, Tri Isopropanolamine 85
TEA 85, Triethanolamine 85
Crude Glycol
Amines bottom
Crude Glicerine 60% min & 80% min
MPEG 500, Methoxy Polyethylene Glycol 500
MPEG 750, Methoxy Polyethylene Glycol 750
MPEG 1000, Methoxy Polyethylene Glycol 1000
.
DYES
LiOH, Lithium Hydroxide
Resorcinol, CAS 108-46-3

.
FLAVOURS & FRAGRANCES
EDG, ethyl diglicol
DMC, dimethyl carbonate
Denatonim benzoate diluted in Ethanol
.
FOUNDRY INDUSTRY
Propylene Carbonate
Ethylene Carbonate
Resorcinol, CAS 108-46-3
Methyl formate, CAS 107-31-3
Bisphenol A
Gamma Butyro Lactone

LEATHER
DMPA, Dimethyl Propionic Acid
Low Dicarboxylic Acids
Pirrolidones
Carbonates
DEO, diethyl oxalate

LUBRICANTS & AUTOMOTIVE PRODUCTS

Sodium pyrithione 40%
Phenoxyethanol
Adipic acid
Brake fluids
Formulated antifreeze
Concentrated antifreeze
Ethanolamines, PEG’s
Chlorinated paraffins
Glycerine
Denatonium Benzoate diluted in MEG
Pine Oil 50% & 80%
MPEG 500, Methoxy Polyethylene Glycol 500
MPEG 750, Methoxy Polyethylene Glycol 750
MPEG 1000, Methoxy Polyethylene Glycol 1000
Benzotriazole
Tolyltriazole
Tolyltriazole Sodium salt 50%

PAPER INDUSTRY
Phosphonates: ATMP, DTPMA, HEDP, PBTC
Glycols
PEG’s
Antifoams

PHARMA

PTSA, Paratoluene Sulphoric Acid
Methyl Cyclohexane
DMSO, Dimethyl Sulfoxide
Acetamide
Dicyanamide
Acetonitrile
Sulfolane
TPP, Triphenylphosphine
THF, tetrahydrofurane
2MeTHF, 2 methyl tetrahydrofurane
Acetic Anhydride
Pharma Glycerine USP & KOSHER certificate

PETROCHEMICAL
Ethanolamines
Sulfolane
MDEA, Methyl Diethanolamine

POLYURETHANES

Amine catalyst (BDMA, DMEA, DMCHA, TEDA)
Potassium catalyst (Octoate, acetate, dilutions)
Tin catalyst (DBTDL, DOTDL, MBTO, DBTO,…)
Bismuth & Zinc Catalyst. Valikat© by Umicore *
DMPA (Dimethylolpropionic acid)
PEG’s (200, 300, 400, 600)
DEEP, Diethyl Ethyl Phosphonate, CAS 78-38-6
TEP,Triethyl Phosphonate
Halogen free flame retardant
TCPP
MDI / TDI
Mannich polyether polyols
Polyether polyols for rigid PU
Polyether polyols for flexible PU foam
Polyether polyols for C.A.S.E.
Aromathic polyester polyols
Forane 365/227 blowing agents by ARKEMA
Chlorinated paraffins
Glycerine
TNBT,  Tetra n-butyl Titanate

RESINS, PAINTS & VARNISHES
Monomers, acrilates
Additives for powder paint
Peroxides
Bisphenol A
Polyester resins for powder coatings
Nonylphenol
TCE, Trichloroethylene
Ethanolamines
AAM, Acrylamide
MAAM, Methacrylamide
Ethylene urea
Bismuth & Zinc catalyst. Valikat© by Umicore
Maleic Anhydride
Dicyandiamide
PTSI, p-Toluenesulphonyl Isocyanate
Triphenil Antimonium
Styrene Monomer
Benzoguanamine
Bio MPG, vegetal propylene Glycol

RUBBER

Solid PEG’s
Plastizicers

TEXTILE INDUSTRY
Ethylene urea
Acrilates & Monomers
PEG’s
ADH, adipic acid dihydrazine
DAAM, diacetona acrilamide
Dicyanamide

WATER TREATMENT

Phosphonates
Benzotriazole
Tolyltriazole
Tolyltriazole Sodium salt 50%
Antifoams

TRADING

Solvents
– Oxos . 2-Ethylhexanol

. Isobutanol

. Butanol

– Mek, Methyl ethyl ketone

– Ipa, Isopropyl alcohol

Glycols
– MEG

– DEG

– TEG

Chlorinates
– Tricloroethylene

Acids
– Acetic Acid
– Formic Acid  85%
Others
– Nonylphenol ethoxilated: NPE-6, NPE-8, NPE-9, NPE-10