MELAMINE PHOSPHATE
MELAMINE PHOSPHATE
Melamine Phosphate (MP) is one typical inorganic phosphorus flame retardant.
Melamine Phosphate
Melamine phosphate is mainly used in intumescent flame retardant systems for paints and polymers, combining both the melamine and catalyst functionality.
Other applications are in thermosets, both unsaturated polyester and epoxies, and in textile treatment.
In self-charring materials such as cellulose or epoxy, melamine phosphates can be used as such without addition of other flame retardants.
ATAMAN CHEMICALS has both Ammonium Polyphosphate and Melamine Phosphate in stocks.
Chemical name Melamine phosphate
CAS: 41583-09-9
Melamine Polyphosphate （MPP）
As a kind of intumescent flame retardant, it can be used separately, also can be used together with other flame retardants.
Mainly used in fire-proof coatings, powder coatings, PA66, PBT, PET, epoxy risen, etc;
Especially suitable for glass fiber-reinforced PA66.
It can meet the processing demands of most engineering plastics.
Categories: Flame Retardant, Halogen-free Flame Retardants
Properties
Halogen-free and low poison, meet European Environmental Protection requirements;
Good processability without special screws combination and special specification glass fiber;
Good heat stability, decomposition temperature is more than 350℃, suitable for glass fiber-reinforced nylon66;
FR-NP100 have good dispersivity to enhance the mechanical properties of the processed products.
Stable product quality to reduce the moisture absorption of the product and make it easy to preserve.
Application
As a kind of intumescent flame retardant, it can be used separately, also can be used together with other flame retardants.
Mainly used in fire-proof coatings, powder coatings, PA66, PBT, PET, epoxy risen, etc;
Especially suitable for glass fiber-reinforced PA66. It can meet the processing demands of most engineering plastics.
Packaging: 25Kg kraft bag with PE bag inner.
Storage: Handle with care, keep airtight and dry.
Name: 1,3,5-triazine-2,4,6-triamine phosphate
Synonyms: MPOP
Melamine-phosphate
Triazine triamine phosphate
CAS: 41583-09-9
56386-64-2
1,3,5-triazine-2,4,6-triamine phosphate
EC / List no.: 255-449-7
CAS no.: 41583-09-9
Mol. formula: C3H9N6O4P
1,3,5-triazine-2,4,6-triamine phosphate
1,3,5-triazine-2,4,6-triamine; phosphoric acid
melamine phosphate
Reaction product of 1,3,5-triazine-2,4,6-triamine and orthophosphoric acid
reaction product of 1,3,5-triazine-2,4,6-triamine phosphate and orthophosphoric acid
Solid Thermoplastics
Polyethylene (PE)
Polypropylene (PP)
Textiles/Paints/Adhesives
Paints
Intumescent coatings
Textile back coating
Thermosets
Unsaturated polyesters
Phenolic resins
Epoxy resins
Melamine phosphate uses and applications include: Flame retardant for plastics, polyolefins, polyester, rubbers, pigmented coatings, latex intumescent coating formulations, paper, textiles; catalyst in intumescent systems; intumescent paintmastic ingredient
Application: Melamine phosphate is an excellent in tumescent Flame Retardant;
it can be applied to polyolefin, linear polyester, polyamide, some thermosetting resins, rubber, paint, latex, paper and textiles and so on.
Flame-retardant effect and mechanism of melamine phosphate on silicone thermoplastic elastomer
Dawei Xu,a Hongchao Lu,a Qiang Huang,b Bofu Dengb and Li Li
Different from the traditional silicone materials, which are not easily ignited, silicone thermoplastic elastomer (Si-TPE) has poor flame retardant properties due to the existence of the hard segments in its molecular chains.
In this paper, melamine phosphate (MP), a kind of halogen free flame retardant, was adopted to improve the flame retardancy of Si-TPE.
The results showed that MP played the role of flame retardant in both gas and condensed phases due to its nitrogen–phosphorus-containing structure.
Inert gases, including nitrogen, steam and ammonia which were released by the degradation of melamine during burning, could take away the heat and dilute the oxygen in the gas phase, and further working with the phosphoric acid, which was generated in the condensed phase, to form a denser and firmer char layer.
In this way, Si-TPE/MP composite with good flame retardancy was obtained. Interestingly, MP had little influence on the thermal processability of Si-TPE, even at 28 wt% content, ascribing to its two opposite effects on Si-TPE, but enhanced the comprehensive mechanical properties of Si-TPE with suitable loadings,
e.g. when the MP content was 28 wt%, the composite reached UL94-V0 rating, and its tensile strength and Young’s modulus were 3.5 MPa and 37.7 MPa, respectively.
Melamine phosphate (MP), a typical halogen-free phosphorus flame retardant, is the reaction product of melamine and phosphoric acid, thus combining the flame retardancy of both melamine and phosphoric acid.
When burning, MP can release phosphorus acids to carbonize and construct a stable and dense charring barrier in the condensed phase to decrease the flammability of a material, and nitrogen, bonded to the triazine rings in MP, can also pass to the gaseous phase, further insulating the material from fire.
It has been reported that phosphorous and silicone have synergistic flame retardancy,21–24 so MP has been widely used in some silicone contained materials to improve their flame retardancy.
For example, Li et al. adopted MP to promote the ame retardancy of a,u-dihydroxy polydimethylsiloxane, and found that MP could accelerate the thermal decomposition of this silicone rubber to form oxygen and heat insulated barrier, thus effectively improving its limiting oxygen index
Melamine phosphates as ecologically friendly, halogen free flame retardants in polymer materials
Flame retardants
Flame retardants (FR) that reduce the rate of combustion are constituted by chemical compounds or the mixtures thereof that deter the time to ignition and decrease the rate of pyrolysis or the oxidation of polymers on contact with a flame.
The onset of thermal degradation of carbon polymers requires the supply of a relatively minor amount of energy that breaks the covalent bond C-C.
The level of energy required for most polymers ranges between 200-400 kJ/mol.
It is a prerequisite for the combustion process to be sustained that the amount of heat transferred by the flame to the sample ensures at least a constant stream of volatile products of pyrolysis that penetrate the flame.
In the event of fire, the flames consume an expanding area, the intensity of the heat stream is on the rise and the entire process is an autocatalytic reaction.
The mechanism involves volatile ammable combustion products which are essential here.
The flame retardant agent systems may either rely on physical (cooling, forming of a protective layer or fuel dilution) or chemical (condensed phase reaction or gas) phenomena, depending on their properties.
They may impact various stages of polymer combustion (heating, pyrolysis, ignition, thermal degradation propagation.
The global market demand for flame retardants applied for polymers in 2011 reached the level of 2,2 mln t/year.
The largest market of flame retardant agents features construction materials and products, electric devices, transportation means as well as furniture and interior fittings sectors.
The increasing stringency of safety and flammability regulations as well as the soaring figures of synthetic polymer products are conducive to an ever broader application of materials with a reduced flammability that may be obtained by the addition of ame retardants to polymers.
The global demand for fire retardant additives is expected to rise by 6.1% annually until 2014.
Halogen free flame retardants
Flame retardants may be divided in terms of either being additive, namely not showing reaction with base polymers, or reactive that are usually combined with the polymer in the course of synthesis (monomers or polymer precursors) or at a post-reaction stage.
Flame retardant additives are incorporated into the polymer chain.
The implementation of the REACH regulation has given rise to systematic study of the impact of chemical substances on the life standard and health of humans as well as on the environment.
Among the substances classified as hazardous and recalled from the market are some agents heretofore applied as re retardants.
Brominated bisphenols have been identified as PBT agents (persistent, bioaccumulative, toxic).
Under the UNEP Stockholm Convention of 2009 it has been prohibited to apply some halogen free retardants and this restraint was enforced in Poland as well as in Europe in 2011.
There have been safety-related objections as regards the application of some volatile organic phosphates but they have not been recalled from the market so far [4÷6].
Organic halogen free FR prove superior not only in terms of high performance but also with respect to the suitability for combining with polymer matrix – as a result of their chemical affinity.
The area of the interface between the dispersed phase and the type of interaction between the continuous and the dispersed phase are two important factors defining the properties of polymers.
Higher shape factor and reduced transverse dimension of the ller particles yield a larger effective area of the ller particle as well as an increase of total of interactions between the polymer matrix and the filler particles.
As a result, the composite usually demonstrates improved mechanical properties but at the expense of the deterioration of the rheological characteristics of the polymer.
The morphological structure of a FR additive, namely the dimensions and geometry of the particles thereof, affects the mechanical properties of the polymer as well as its “fitness for processing”.
The requirements of small size, low shape factor as well as a minimum effective area may be assumed for polypropylene and polyamide fillers.
The objective is to identify flame retardants and the systems thereof that remain efficient at low content in polymer.
Retardant additives prevail among marketable halogen free flame retardants.
The following may be specified, in the order of significance:non-organic hydroxides,
e.g. of aluminum or magnesium
• non-organic and organic phosphate compounds, including
• phosphates, phosphites, red phosphorusnitrogen compounds, including melamine and its salts
• retardants and intumescent retardant systems, characterised
• by various chemical structure, predominantly with a polyphosphate contentmineral and synthetic silicon compounds, including modified
• aluminum-silicon nanofillers.
Melamine phosphates as FR additivesPhosphorus and nitrogen compounds, including polyphosphates, are of significance on the market of halogen free flame retardants.
The most popular and best described among them is ammonium polyphosphate.
Melamine salts have gained less popularity but show a growing importance.
Melamine (2,4,6-triamine-1,3,5-triasine) is crystalline solid with melting point at 345oC, and nitrogen content as high as 67 %.
It sublimates already at 350oC because of high heat adsorption rates.
At a slightly higher temperature, it undergoes degradation, releasing ammonium and forming temperature resistant condensates.
Both melamine and its salts such as cyanurate, oxalate, phthalate, borate as well as the most popular phosphates are applied as flame retardants.
Of interest are the following: orthophosphate, diphosphate (or pyrophosphate) and melamine polyphosphate.
Melamine polyphosphate has a lower phosphate content than the popular ammonium polyphosphate (approx. 30% as opposed to approx. 60 % in ammonium polyphosphate) but contains signicantly more nitrogen.
The nitrogen bound within a stable melamine ring is released from melamine phosphates and transfers to gaseous phase at temperatures higher than 300oC, at the expense of ambient heat absorption.
The synthesis of melamine phosphate, pyrophosphate and polyphosphate involves the following reactions, specified here in a simplified form:
C3N6H6 + H3PO4 → C3N6H6· H3PO4 melamine phosphate MP2 C3N6H6· H3PO4
(C3N6H6HPO3)2 + H2Omelamine pyrophosphate MDP(C3N6H6HPO3)2 + (n-2)C3N6H6· H3PO4
(C3N6H6HPO3)n + (n-2)H2Omelamine polyphosphate MPP
Subsequent products of the condensation of phosphates differ mainly in terms of thermal resistance.
MPP is designed mainly for polymers processed at higher temperatures, e.g., polyamide.
The synthesis of melamine polyphosphate following the IChN methodology has been demonstrated in Figure 1 which shows a model of a technical process developed by means of a derivatograph manufactured by Metler-Toledo.
Initially, a sample (MP) was heated at the rate of 1.3oC/minute, with the material subjected to the temperature of 300oC for 75 minutes.
Figure 1 indicates the respective differential effects of mass loss (as established by means of differential thermal gravimetry – DTG) accompanying the transformation process: MP into MDP and, subsequently, into MPP.
Melamine polyphosphate, derived in an analogous way and pulverised to the particle size range of 5-10 µm, was deployed for the purpose of the preparation of multiple compositions of various polymers (PEHD, PA6, PP, EVA) that served to obtain granulates and samples for flammability tests.
Thus, the robustness of MPP as a flame retardant was tested and appropriate mechanical properties of the products and rheological compositions were provided
The properties of polymer materials, including flame and fire resistance as well as the their behaviour in case of fire, are determined by the parameters of all the components of the polymer product: polymer, fillers, flame retardants and other additives.
The efcacy of flame retardants may be estimated by various standards, for instance, basing on the heat release rate (HRR) as well as the amount and type of toxic products of polymer pyrolysis and combustion.
The heat release rate of polymer materials directly correlates with mass loss rate during heating and is a function of the amount of heat energy yielded by the ame and transferred to the non-burning surface of the material.
Apart from an increased flame resistance of the materials, the following are required: reduced smoke emission and the elimination of toxic combustion products from the process.
Laboratory tests of the flammability of polymer materials differ to a considerable extent.
The attempts of establishing conformity criteria between respective types of tests for either flame retardant polymer materials considered globally or for particular polymer group have failed.
The most significant tests in practical terms are: the oxygen index LOI established in accordance with ISO 4589 as well as the counterparts thereof: ASTM D 2863 and PN-EN ISO 4589-2:2006, UL-94 test as well as cone calorimeter.
LOI method proves the most universal as it may be applied for a spectrum of flammable and non-flammable materials.
The LOI oxygen index is defined as the lowest oxygen content (expressed as volumetric %) that is sufficient for sustaining the combustion of a polymer with a candle-like ame with the initial temperature equal to room temperature.
Hence, materials with LOI levels exceeding standard oxygen content in air should be self-extinguishing.
The UL 94 method has been set by the American Underwriters Laboratories as a standard for tests of flammability and fire safety of polymers used in equipment and devices.
The UL 94 HB (horizontal flame propagation) test investigates the course of the combustion of a horizontally oriented element from a polymer, while the more sophisticated UL 94 V (vertical flame propagation) test – the course of the combustion of a vertically oriented element.
The Polish statutory counterpart is the standard PN-EN ISO 9773:2003.
The Polish standard evaluates the glow duration and route; moreover, it requires that there are no fragments detached from any burning or glowing sample and falling onto cotton pieces underneath the samples.
This is the most straightforward test for the assessment of industrial materials that is of little use for the purpose of determination of material characteristics or the mechanism of combustion.
Conclusions
In view of higher consumer and industry expectations of polymer materials, and also demands for a reduced material flammability as well as the pressure to use environmentally-friendly and human-friendly flame retardants, melamine phosphates are an appealing option on the market.
Their practical signicance is on the rise. Most promising results in terms of the reduction of the flammability of polymer materials can be seen for polypropylene and polyamide.
There has been a growing body of literature on the application of melamine phosphates in complex retardant systems, also for polymers other than polyamides and polyolephines.
1,3,5-TRIAZINE-2,4,6-TRIAMINE PHOSPHATE
1,3,5-Triazine-2,4,6-triamine phosphate (1:1) [ACD/IUPAC Name]
1,3,5-Triazine-2,4,6-triamine, phosphate (1:1) [ACD/Index Name]
20208-95-1 [RN]
243-601-5 [EINECS]
255-449-7 [EINECS]
41583-09-9 [RN]
Acide phosphorique – 1,3,5-triazine-2,4,6-triamine (1:1) [French] [ACD/IUPAC Name]
melamine phosphate
Phosphorsäure –1,3,5-triazin-2,4,6-triamin (1:1) [German] [ACD/IUPAC Name]
[20208-95-1]
1,3,5-triazine-2,4,6-triamine monophosphate
1,3,5-Triazine-2,4,6-triamine, phosphate
163183-93-5 [RN]
56974-60-8 [RN]
INTUMESCENTCOMPOUNDKE8000
melamine [Wiki]
Melamine phosphate MP
Melamine polyphosphate
MELAMINE; PHOSPHORIC ACID
Melamine-phosphate
MELAMINE-PHOSPHONATE
MFCD00060248
Phosphoric acid [ACD/Index Name] [ACD/IUPAC Name] [Wiki]
Triazinetriaminephosphate
Halogen free flame retardants
The trend towards more stringent requirements for flame retardancy in aircraft interiors, with concerns about increased regulatory requirements for halogenated flame retardants, is forcing developments in the direction of non-halogenated alternatives.
Regulatory compatibility
Halogen, antimony and metal free flame retardants
Allows finished products to conform to eco-labels
Protection throughout product lifecycle
Lower smoke density
Less corrosive to processing equipment
Reduces ancillary damage to equipment and material in case of fire
Offers flexibility in use
Allows for broader coloration options
Can be incorporated into a variety of applications
Can be used alone or synergistically with other materials
All Melapur flame retardants are free of halogens, antimony or any other heavy metals. The Melapur flame retardant product range comprises Melapur MC (melamine cyanurate), Melapur MP (melamine phosphate) and Melapur 200 (melamine polyphosphate).
Melapur MP flame retardants
Melapur MP flame retardant is a salt of melamine and phosphoric acid.
Above 200 ºC, it reacts to release water, resulting in a heat sink and leaving the phosphorous component available to react synergistically with other flame retardant components.
Therefore, Melapur MP flame retardant is often used in blended flame retardant systems for applications, such as coatings and sealants.
Protection throughout product lifecycle
Lower smoke density
Less corrosive to processing equipment
Reduces ancillary damage to equipment and material in case of fire
Offers flexibility in use
Allows for broader coloration options
Can be incorporated into a variety of applications
Can be used alone or synergistically with other materials
All Melapur flame retardants are free of halogens, antimony or any other heavy metals.
The Melapur flame retardant product range comprises Melapur MC (melamine cyanurate), Melapur MP (melamine phosphate) and Melapur 200 (melamine polyphosphate).
Picture
Stand alone and synergiestic flame retardancy
The table below demonstrates the considerable advantages of Melapur flame retardants compared to other major flame retardant systems. While Melapur flame retardant is often used as a stand alone, it is also used regularly as an effective synergist with other flame retardants to improve the overall performance of the flame retardant system. Please talk to us for further information regarding these applications and the benefits of Melapur flame retardants in them.
MELAMINE PHOSPHATE
APPLICATION
Can be applied to polyolefins, linear polyester, polyamide, some thermosetting resins, rubber, paint, latex, paper, and textiles.
BENEFITS
Excellent intumescent flame retardant
PACKING
25 kg/paper bag (plastic liner/paper bag)
Melamine Cyanurate
Melamine Polyphosphate
Melamine Pyrophosphate
Melamine Phosphate
Melem
Piperazine Pyrophosphate (modified)
Ammonium Polyphosphate water-soluble
Ammonium Polyphosphate phase II
Ammonium Polyphosphate phase II with melamine treatment
Ammonium Polyphosphate phase II with silane treatment
Ammonium Polyphosphate phase II with epoxy treatment
Red Phosphorus Paste
Zinc Borate
Partial ATO replacement
Specialty FR for PE
DOPO
1,3,5-triazine-2,4,6-triamine polyphosphate; INTUMESCENT COMPOUND KE 8000; SLFR-7; 1,3,5-triazine-2,4,6-triamine monophosphate; 1,3,5-Triazine-2,4,6-triamine, phosphate (1:1); Non-halogen flame-retardant MP; 1,3,5-Triazine-2,4,6-triamine·phosphoric acid; Melamine phosphoric acid;Melamine polyphosphate;Melamine phosphate;Melamine orthophosphate
Synonyms
1,3,5-Triazine-2,4,6-triamine/phosphoric acid,(1:x)
1,3,5-triazine-2,4,6-triamine phosphate
1,3,5-Triazin-2,4,6-triaminphosphat
triazine triamine phosphate
1,3,5-Triazine-2,4,6-triamine,phosphate (1:)
trimelamine diphosphate
[1,3,5]triazine-2,4,6-triyltriamine,phosphate
INTUMESCENT COMPOUND KE 8000
Einecs 255-449-7
MELAMINE PHOSPHATE
[1,3,5]Triazin-2,4,6-triyltriamin,Phosphat
SLFR-7
Melamine phosphate is a salt of melamine and phosphoric acid, suitable for use as a component for formulating intumescent flame retardarding systems.
Product forms
White powder
Applications
Melamine phosphate, is mainly used in intumescent flame retardant systems for paints and polymers, combining both the melamine and catalyst functionality.
Other applications are in thermosets, both unsaturated polyester and epoxies, and in textile treatment.
In self-charring materials such as cellulose or epoxy ,melamine phosphates can be used as such without addition of other flame retardants.
Benefits
Melamine phosphate is a halogen-free flame retardant.
Above ∼ 200 °C melamine phosphate reacts to melamine pyrophosphate, releasing water, which will result in a heat sink effect.
Melamine phosphate is a halogen free FR and offers significant advantages in terms of fire safety, i. e. lower smoke density, lower smoke toxicity and less corrosive gases.
Melamine phosphate as a component of intumescent coatings
Michael Kay
Chemical Eng & Applied Chemistry
Student thesis: Doctoral Thesis › Doctor of Philosophy
Abstract
Melamine orthophosphate has been shown to exhibit variations in its chemical constitution, and crystal shape and size, dependent upon the method of production.
These crystal types have been incorporated with epoxy resin to produce intumescent coatings, which have been tested on a small scale fire testing device, designed and calibrated within this project.
The factors influencing performance in three fire test regimes are the percentage loading of melamine phosphate, its chemical constitution, crystal size and shape, thermal degradation, and state of agglomeration and dispersion in the coating, determined by the method of incorporation into the coating.
When melamine phosphate is heat treated at 210ºC, a process designed to reduce its solubility, the performance of coatings produced with such material is profoundly affected, depending mainly on crystal size and shape alone.
Consideration of heat transfer across the chars produced has allowed a quantitative evaluation of the thermal resistance of chars throughout a test.
An optimum production route for melamine phosphate has been suggested, taking into account the requirements for weatherability of coatings as well as performance in a fire.
Date of Award 1980
Original languageEnglish
Keywords
melamine phosphate
component intumescent coatings
fire testing
fire protection
intumescence
melamine polyphosphate (mp) | einecs 243-601-5 | melamine phosphate (mp) | melamine polyphosphate | intumescent compound ke 8000 | non-halogen flame-retardant mp | melamine phosphoric acid | melamine polyphosphate (mpp) | slfr-7 | phosphoric acid·melamine
Melamine phosphate
20208-95-1
Melamine polyphosphate
1,3,5-Triazine-2,4,6-triamine, phosphate
1,3,5-triazine-2,4,6-triamine phosphate
41583-09-9
INTUMESCENTCOMPOUNDKE8000
1,3,5-Triazine-2,4,6-triamine monophosphate
1,3,5-Triazine-2,4,6-triamine, phosphate (1:?)
phosphoric acid;1,3,5-triazine-2,4,6-triamine
EINECS 255-449-7
EINECS 243-601-5
1,3,5-Triazine-2,4,6-triamine, phosphate (1:1)
EC 255-449-7
SCHEMBL73239
C6H9N6O4P
phosphoric acid; 1,3,5-triazine-2,4,6-triamine
DTXSID80872787
EINECS 260-493-5
AKOS028108538
AS-15268
O688
FT-0628188
FT-0742330
Di(1,3,5-triazine-2,4,6-triamine) phosphate
583M099
A831966
1,3,5-Triazine-2,4,6-triamine, phosphate (2:1)
218768-84-4
1,3,5-TRIAZINE-2,4,6-TRIAMINE PHOSPHATE
1,3,5-Triazine-2,4,6-triamine phosphate (1:1) [ACD/IUPAC Name]
1,3,5-Triazine-2,4,6-triamine, phosphate (1:1) [ACD/Index Name]
20208-95-1 [RN]
243-601-5 [EINECS]
255-449-7 [EINECS]
41583-09-9 [RN]
Acide phosphorique – 1,3,5-triazine-2,4,6-triamine (1:1) [French] [ACD/IUPAC Name]
melamine phosphate
Phosphorsäure –1,3,5-triazin-2,4,6-triamin (1:1) [German] [ACD/IUPAC Name]
[20208-95-1]
1,3,5-triazine-2,4,6-triamine monophosphate
1,3,5-Triazine-2,4,6-triamine, phosphate
163183-93-5 [RN]
56974-60-8 [RN]
INTUMESCENTCOMPOUNDKE8000
melamine [Wiki]
Melamine phosphate ?MP?
Melamine polyphosphate
MELAMINE; PHOSPHORIC ACID
Melamine-phosphate
MELAMINE-PHOSPHONATE
MFCD00060248
Triazinetriaminephosphate
Intumescent systems are alternatives to inorganic materials in final applications with fire resistance time (FRT) requirements, such as R60′ or REI 30′.
Main applications are intumescent coatings (IC) for the protection of steel structures, but these special paints can also be applied to other substrates such as concrete, wood, cables etc. either to reduce their flammability (‘reaction-to-fire’) and/or to maintain their function in the event of fully developed fire (‘fire resistance’).
Other applications also include fire resistant sealants where the gap-filling material is also expected to restore the fire resistance properties of the treated area.
Textiles – Coating Textiles – Non Durable Textiles – Semi Durable Textiles – Durable Plastics – Films, Tapes and Thin walled applications Plastics – Thermoplastics Plastics – Thermosets Intumescent Systems Wood Leather Specialities
Intumescent flame retardant systems
Mode of action: formation of a voluminous, insulating protective layer through carbonization and simultaneous foaming
Intumescent systems puff up to produce foams.
They are used to protect combustible materials such as plastics or wood, and those like steel, which lose their strength when exposed to high temperatures, against the attack of heat and fire.
Basically, intumescent flame retardant systems consist of the following:
1. “Carbon” donors (e.g. polyalcohols such as starch, pentaerythritol)
2. Acid donors (e.g. ammonium polyphosphate)
3. Spumific compounds (e.g. melamine)
Process of intumescent mechanism
1. Softening of the binder/polymer (e.g. polypropylene)
2. Release of an inorganic acid (e.g. ammonium polyphosphate)
3. Carbonization (e.g. of polyalcohols)
4. Gas formation by the spumific compound (e.g. melamine)
5. Foaming of the mixture
6. Solidification through cross-linking reactions
This coating expanded from a 1 mm layer to a 100 mm foam.
Flame retardants in everyday life
Flame retarded products in everyday life
Flame retardants are used to improve the fire safety of combustible products and materials in all sectors of our everyday life.
These are:
Buildings (insulation material, water pipes, facade facings)
Electrical/Electronics (monitor housings, cables, plugs, fuse boxes, circuit boards)
Transportation (automotive, railway, ships, aircraft, with seats, floorings, linings, insulation)
Upholstered furniture
Flame retardants help to save lives by slowing down or stopping the spread of fire or reducing its intensity.
Also called fire retardants, they are used in anything from phones and curtains to car seats and buildings.
If a fire starts, they may be able to stop it completely – or slow it down and so provide precious extra time for escape.
ATAMAN’s flame retardants are produced to modern standards in Germany, Switzerland and China.
With our non-halogenated, phosphorus-based flame retardants, you add more than reliable fire resistance to materials, products and coatings
Melamine phosphates of various degree of polycondensation such as melamine phosphates (MP), melamine polyphosphates (MPP) and melamine pyrophosphates (MDP) are used increasingly as flame retardants (FR), particularly as additives to plastics.
Products made of plastics consist flame retardants.
Until this moment, the flame retardants were halogenated compounds which decompose in increased temperature releasing additional harmful substances.
According to REACH classification, many of chlorine derivative flame retardants are classified as PBT substances (persistent, bioaccumulative and toxic).
Due to this fact, their application is prohibited or amount is strictly limited.
Regarding to the above, it is very important to develop technologies to produce halogen-free flame retardants.
In one of the groups of these products are materials based on melamine phosphate in various degrees of polycondensation.
These agents, as compared to traditional flame retardants, are more environment friendly, as at elevated temperatures they do not release halogenated compounds, in particular toxic compounds of bromine.
Melamine phosphates contain less phosphorus than the popular ammonium polyphosphate.
However, the decomposition of the melamine ring at temperatures above 300 °C occurs with the absorption of heat from the surroundings due to release of the nitrogen.
This makes melamine phosphates useful as flame retardants for polymeric materials that require high-temperature processing or that are designed for use at elevated temperatures.
MP is widely used to improve fire resistance of many polymeric materials and coatings and is an important intermediate for obtaining melamine polyphosphate (MPP).
Melamine polyphosphate (MPP) exhibits excellent thermal resistance and no significant mass loss up to temperatures of over 300 °C.
The effects of MPP application in various polymeric materials, such as polyamides, polypropylene, epoxy compositions and polyurethane, have been described in many publications.
Melamine phosphates have to be stable in the molding process of plastics.
However, they have to decompose during the fire and limit the spread of flame.
Describing its thermal properties limits their range of applications.
Temperature of retardant decomposition has to be strictly connected with temperature of polymer degradation.
This is a reason why phosphates at different condensation degree are applied.
There are many methods of preparing melamine polyphosphate described in the literature; two of them were described back in the 1940s.
One consisted in producing melamine orthophosphate suspension from orthophosphoric acid and melamine followed by calcination at 250–270 °C.
The other consisted in reacting melamine with tetrasodium pyrophosphate in a solution with an addition of hydrochloric or nitric acid.
Modern methods involve reacting melamine with phosphoric or polyphosphoric acid at ambient temperature.
Preparing MPP as flame retardant component in plastics was described in many patents.
Solid particles of sparingly water soluble melamine suspended in water react quite rapidly with phosphoric acid to form a solid precipitate.
The reaction product requires post-curing at 250–350 °C.
The reaction may be carried out either in batch or continuous mode .
The synthesis of melamine phosphate, pyrophosphate and polyphosphate can be described by the following equations:
C3N6H6+H3PO4→C3N6H6⋅H3PO4−melaminephosphate(MP)(1)
2C3N6H6⋅H3PO4⟶250−300∘C(C3N6H6HPO3)2+H2O−melaminepyrophosphate(MDP)(2)
(C3N6H6HPO3)2+(n−2)C3N6H6⋅H3PO4⟶300−330∘C(C3N6H6HPO3)n+(n−2)H2O−malaminepolyphosphate(MPP)(3)
The processes, however, particularly those that proceed in solid state, are in fact more complex.
Upon heating, melamine phosphate undergoes condensation followed by thermal decomposition.
The theoretical mass loss in the first stage of condensation (Eq. 2) due to the water release equals 4.0 %.
This has been confirmed experimentally.
The second stage of condensation (Eq. 3) is less straightforward; apart from simple condensation of the pyro form to poly forms which proceeds with release of water, also thermal decomposition occurs simultaneously; moreover, products of various degree of condensation are obtained.
To establish exact composition of product, both thermal analysis (TG/DTG, DSC) and spectroscopy can be applied.
The aim of the work was to study the kinetics of melamine phosphate decomposition (dehydration) to pyrophosphate and then to polyphosphate. Earlier investigations of thermal decomposition of melamine phosphate focused mainly on melamine pyrophosphate preparation and involved TG/DTG techniques.
In previous work, we determined kinetic parameters of the first stage of condensation (formation of melamine pyrophosphate) with the use of TG/DTG method.
In this work, to determine kinetic relations of two subsequent stages of melamine polyphosphate synthesis, we applied differential scanning calorimetry (DSC).
We used the Kissinger method, Kissinger–Akahira–Sunose isoconversional method and reaction model fitting method to obtain kinetic parameters and establish a kinetic model of two last stages of melamine polyphosphate synthesis, as a part of work on developing of a method of production of melamine phosphate flame retardant.
Flame retardant products
Abstract
A composition of matter (host material) has embodied therein a flame retardant material which comprises a combination of a phosphorus containing material which decomposes to produce phosphoric acid when exposed to flame (e.g. ammonium polyphosphate and/or melamine phosphate) and an oxygenated heterocyclic thermoplastic resin (e.g. an aldehyde resin).
A blowing agent (e.g. melamine) also may be included in the flame retardant material.
The thermoplastic resin encapsulates the other ingredients thus making the flame retardant melt blendable with the host material (e.g. thermoplastic polymers, thermosetting polymers, solvented systems, paper and reconstituted wood products) in which it is incorporated.
A composition of matter (host material) has embodied therein a flame retardant material which comprises a combination of a phosphorus containing material which decomposes to produce phosphoric acid when exposed to flame (e.g. ammonium polyphosphate and/or melamine phosphate) and an oxygenated heterocyclic thermoplastic resin (e.g. an aldehyde resin).
A blowing agent (e.g. melamine) also may be included in the flame retardant material.
The thermoplastic resin encapsulates the other ingredients thus making the flame retardant melt blendable with the host material (e.g. thermoplastic polymers, thermosetting polymers, solvented systems, paper and reconstituted wood products) in which it is incorporated.
lame retardant products exhibiting intumescent properties are well known. Such flame retardant products are incorporated in many compositions of matter, (host materials), especially thermoplastic polymer compositions.
One such flame retardant product is a blend of a phosphoric acid producing catalyst, a charring agent and a blowing agent.
The catalyst is a compound, e.g. ammonium polyphosphate, which when exposed to flame yields phosphoric acid.
The charring agent can be a polyhydric alcohol, e.g. pentaerythritol, which decomposes and reacts with phosphoric acid to form a carbonaceous char.
The blowing agent, e.g. melamine, when exposed to flame produces a non-flammable gas (e.g. N2) which serves to foam and expand the carbonaceous char.
The above mentioned three component flame retardant products are powder additives which have processing limitations as they do not blend well with many compositions of matter (host materials), e.g. thermoplastics.
In order to overcome these processing problems there have been attempts to encapsulate the flame retardant additives in inert polymers.
However, there is a disadvantageous limit on the amount of such encapsulated flame retardant product that can be incorporated in the host materials and the encapsulants themselves are generally flammable materials.
Proprietary flame retardant products have appeared on the market which typically are reaction products of pentaerythritol and phosphate esters.
These flame retardant products are melt blendable with host materials such as thermoplastic polymers. However, such proprietary flame retardant products have to be used in combination with other flame retardants.
Furthermore, such proprietary materials do not contain blowing agents and so do not have the advantages of char foaming and expanding.
Phosphorus was discovered by its spectacular reaction with air – white phosphorus catches fire spontaneously.
Sadly phosphorus has been used in incendiary bombs and burning phosphorus is difficult to put out.
However, once oxidised to phosphates (O.S. +5), the most stable oxidation state for phosphorus, the compounds cannot be oxidised further and are thus fire-resistant.
Phosphates are important additives to confer fire-resistance to otherwise flammable materials such as wood, paper and textiles.
Ammonium dihydrogenphosphate (NH4H2PO4) is used to make paper and fabrics fire-resistant and is made by neutralising phosphoric acid with ammonia.
More ammonia will give ammonium hydrogenphosphate ((NH4)2HPO4) but this decomposes on heating losing ammonia and reverting to the dihydrogenphosphate.
Ammonium phosphate ((NH4)3PO4) is even more unstable to heat.
(Ammonium phosphates are also used in fertilisers and in dyeing textiles)
The use of ammonium phosphates as fire retardants was first proposed by Gay-Lussac in 1891.
Acids slow down the combustion of cellulose by producing carbonaceous char, rather than flammable gases, which prevents further combustion, although acids can also damage the fibres but the ammonium hydrogenphosphates decompose on heating, losing ammonia, and producing phosphoric acid which then slows down the combustion of cellulose.
To flameproof cloth or paper, they are sprayed with or dipped in ammonium phosphate solution and then dried, taking up 3-5% by mass of the retardant.
Timber and wallboards are also fireproofed in the same way but the fire-proofing is removed by water.
Wooden and paper matches are also treated with ammonium phosphate to prevent after-glow when the match is extinguished.
This type of fireproofing is limited to to internal use.
Another important fire-retardant is urea phosphate, a 1:1 adduct of urea (a base) with phosphoric acid.
Cotton is fire-proofed by soaking in a solution of urea phosphate, so that there is about a 15% increase of dry mass.
The dried fabric is then heated to 160oC, the urea partly decomposes and the phosphate is bound to the cellulose.
This treatment does not wash off easily, but fire-proofing is reduced by prolonged washing.
The treatment also reduces the strength of the fabrics and their wear resistance.
Melamine phosphate can be used to treat wood.
Another phosphorus compound, tetrakis(Hydroxylmethyl)phosphonium chloride, (HOCH2)4PCl or THPC, is used as a fire-retardant for nightwear.
The phosphorus compounds are bonded covalently to the cellulose chains, without any soluble ions involved, and so they are wash-resistant.
This process is expensive and almost doubles the cost of the garment.
This process was invented by John D. Guthrie and Wilson A. Reeves in 1953.
Ammonium polyphosphate is also used, the ammonium salt of polyphosphoric acid.
It decomposes on heating to give polyphosphoric acid and ammonia.
The organic surface layer is dehydrated to form carbon, giving a charred carbon foam surface layer which resists further burning.
The surface swells and foams protesting the underlying material, a process known as intumescence.
This process is used to protect structural steel using fire-retardant paint.
Amazingly red phosphorus is also used as a fire-retardant additive for plastics such as polyamides, polyesters and polyurethanes, which are loaded with 2-10% red phosphorus.
When burnt the phosphorus abstracts oxygen and water from the polymer to form phosphoric acid and leaving a fire-resistant char behind.
Flame retardant chemicals work in one or more of the following ways:
promotion of char formation
conversion of combustible gases to non-flammable gases
forming a glaze barrier at the surface
forming an intumescent barrier at the surface
free radical termination in the gaseous phase
The chapter on flame retardants in Toy and Walsh describes many other phosphorus-based fire
retardants. Borates are also used in fire-proofing.