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Send EmailMelamine Phosphate, MP, Melamine Pyrophosphate, MPP, Melamine Polyphosphate, MPP-Poly, 41583-09-9, 15541-60-3, 218768-84-4
Product Class: Organophosphorus and Nitrogen Synergistic Condensed Phase Intumescent Systems
Products Covered:
Melamine Phosphate (MP) | CAS: 41583-09-9
Melamine Pyrophosphate (MPP) | CAS: 15541-60-3
Melamine Polyphosphate (MPP-Poly) | CAS: 218768-84-4
| Parameter | Melamine Polyphosphate (MPP-Poly) | Melamine Pyrophosphate (MPP) | Melamine Phosphate (MP) |
|---|---|---|---|
| CAS Number | 218768-84-4 | 15541-60-3 | 41583-09-9 |
| EC Number | Polymer (monomer registration separate) | 239-590-1 | 255-449-7 |
| Chemical Formula | [C3H6N6⋅(H3PO4)n][C3H6N6⋅(H3PO4)n] | C3H10N6O7P2C3H10N6O7P2 | C3H9N6O4PC3H9N6O4P |
| Molecular Weight | Polymeric (n>100) | 304.10 g/mol | 224.12 g/mol |
| Appearance | White powder | White powder | Off-white fine powder |
| Odor | Odorless | Odorless | Odorless |
Chemical Structure and Explanation:
The compounds in this series are stoichiometric coordination complexes of inorganic acid sources (orthophosphate, pyrophosphate, polyphosphate oligomers) with the melamine base, which acts as an intumescent agent and gas source. During a fire, they catalyze the dehydration of polymer chains in the condensed phase to form a protective carbonaceous char while diluting the combustion atmosphere through endothermic decomposition reactions in the gas phase.
MPP-Poly: A macromolecular salt structure with a high degree of polymerization (n>100) formed by linear dehydro-condensation bridges (−P−O−P−−P−O−P−) of phosphorus atoms. The high degree of polymerization maximizes hydrolytic stability and prevents free phosphoric acid release during high-temperature extrusion.
MPP: A crystal lattice structure formed by the melamine cation with the pyrophosphoric acid anion, which results from the dimerization of two phosphoric acid molecules through the loss of water. Thermal activation threshold is ≥300∘C≥300∘C.
MP: A monoradical monomeric salt formed by the melamine monomer with a single orthophosphoric acid molecule through weak hydrogen bonds and ionic interactions. It begins to decompose around ∼240−250∘C∼240−250∘C .
| Property | MPP-Poly | MPP | MP |
|---|---|---|---|
| Mass Density (g/cm³) | 1.85 | 1.80 | 1.7 (23°C) |
| TGA Pyrolysis Onset (°C) | ≥320∘C≥320∘C | ≥300∘C≥300∘C (1% loss at 372.1°C for high-stability grade) | >250∘C>250∘C |
| D₅₀ Particle Size | ≤5 μm≤5 μm | ≈5 μm≈5 μm | <4 μm<4 μm |
| D₉₈ Particle Size | ≤35 μm≤35 μm | ≤25 μm≤25 μm | <25 μm<25 μm |
| pH (10% suspension) | 5.0±0.55.0±0.5 | 3.5±0.53.5±0.5 | 4-6 (saturated solution) |
| Water Solubility (20°C) | ≤0.01 g/100ml≤0.01 g/100ml | 375 mg/L (0.0375 g/100ml) | 0.35 g/100ml |
| Nitrogen Content | 42-44 wt% | ≥38.0%≥38.0% | ≥37.0%≥37.0% |
| Phosphorus Content | 12-14 wt% | ≥14.0%≥14.0% | ≥12.5%≥12.5% |
| Moisture Content | <0.3 wt% | ≤0.20%≤0.20% | ≤0.5%≤0.5% |
Additional Verified Data:
MPP has a 1% mass loss temperature of 372.1°C and a char residue of 38.5% at 650°C for high thermal stability grades . MPP is described as "the least water soluble of the available melamine phosphates" based on the 375 mg/L measurement at 20°C .
MPP-Poly (commercial grade Melapur 200/70) has D99 ≤ 70 μm and D50 ≤ 10 μm per BASF specifications .
MP thermal decomposition point is >250°C, and specific gravity is 1.7 g/cc at 23°C .
| Analytical Parameter | MPP-Poly | MPP | MP | Standard Test Protocol |
|---|---|---|---|---|
| Molecular Purity (%) | Oligomeric distribution | ≥99%≥99% | ≥98.0≥98.0 | HPLC |
| Mass Nitrogen (N) | 42-44 wt% | ≥38.0%≥38.0% | ≥37.0%≥37.0% | CHNS-O Elemental Analysis |
| Mass Phosphorus (P) | 12-14 wt% | ≥14.0%≥14.0% | ≥12.5%≥12.5% | ICP-OES |
| Free Melamine | Not detectable (bound) | ≤0.5%≤0.5% | ≥54.0%≥54.0% | Potentiometric Titration |
| Combined Phosphoric Acid | Polymeric network | Pyrophosphate building block | ≥41.0%≥41.0% | Ion Chromatography |
| Residual Moisture | <0.3% | ≤0.20%≤0.20% | ≤0.5%≤0.5% | Karl Fischer |
| Solvent | MPP-Poly | MPP | MP |
|---|---|---|---|
| Water (20°C) | <100 mg/L (22°C, reported range varies) | 375 mg/L | 0.35 g/100ml (3.5 g/L) |
| Ethanol | Insoluble | Insoluble | Insoluble |
| Acetone | Insoluble | Insoluble | Insoluble |
MPP's low water solubility prevents additive migration, surface blooming, and degradation of flame retardant performance in humid or wet environments . MP has the highest water solubility among the three products, which limits its use in applications requiring long-term moisture resistance .
The thermal stability ranking of the melamine phosphate family is well established in the literature:
Melamine Phosphate (MP) < Melamine Pyrophosphate (MPP) < Melamine Polyphosphate (MPP-Poly)
| Product | Maximum Practical Processing Temperature | Suitable Polymer Matrices |
|---|---|---|
| MP | ~250°C | Polyolefins, polyurethanes, moderate-temperature engineering resins |
| MPP | ~300-325°C (1% loss at 372°C for high grade) | PBT, PA6, PA66 (including glass fiber reinforced) |
| MPP-Poly | >320°C (up to 350°C) | High-temperature polyamides, PBT, glass fiber reinforced PA66 |
MP begins endothermic dehydration to melamine pyrophosphate above ~200°C. MPP can withstand processing temperatures up to 320-350°C without decomposition . Glass fiber reinforced polyamides processed above 280°C require MPP or MPP-Poly.
Polyamide (PA6/PA66) Systems: In glass fiber reinforced (30% GF) engineering plastics, high shear rates and temperatures >290°C are involved. MPP-Poly blocks the thermal oxidation steps of polyamide chains. When injected at 18-25% concentration, it stops the polymer's dripping tendency and permanently achieves a V-0 rating at 1.6 mm thickness according to UL-94 .
MPP-based flame retardant systems in glass-fiber reinforced PA66 typically use 15-20 wt% of a phosphinate/MPP blend (2:1 ratio) to achieve UL-94 V-0 .
Polyurethane (PUR/PIR): Due to its fine morphology, MPP integrates into the mixture without inhibiting the isocyanate/polyol gelation reaction. It does not disrupt the cell structure.
Polyolefin (PP/PE): In a polypropylene composite containing a piperazine pyrophosphate/melamine polyphosphate (PPAP/MPP) system, addition of only 0.5 wt% ZnO increased the Limiting Oxygen Index (LOI) from 29.9% to 32.3% and improved the UL-94 rating from V-2 to V-0 .
| Sector | MPP-Poly | MPP | MP |
|---|---|---|---|
| Electrical/Electronics | PA66 connectors, circuit breaker housings | PCB laminates, capacitor films | Epoxy resin systems |
| Automotive | Battery enclosures, interior trim | Battery boxes, cable channels | PU coatings |
| Construction/Building | Polyamide-based composites | Intumescent paints, fire barriers | PP-wood flour composites |
| Textiles | - | Industrial protective fabrics | PU coating backings |
| Coatings | - | Water-based intumescent paints | Bio-based PU coatings |
MP is intended as a halogen-free flame retardant/smoke suppressant for thermoplastics, polyolefins, elastomers, engineering resins, paints, and intumescent fire retardant coatings; it can partly replace Ammonium Polyphosphate (APP) . Suggested dosage for polymer or intumescent coatings is 25-30% .
In thermoplastic polyurethane (TPU) biocomposites, MP achieves UL-94 V-0 at 20 wt% loading. In bio-based PU coatings at 20% loading, MP reduced smoke release whereas APP did not demonstrate this smoke suppression benefit .
| Criterion | MP | MPP | MPP-Poly |
|---|---|---|---|
| Thermal stability | Low (~250°C) | Medium (~300°C; 372°C 1% loss high grade) | High (>320°C) |
| Water solubility | High (0.35 g/100ml) | Low (375 mg/L) | Very low (<100 mg/L) |
| Polymer compatibility | PP, PE, PU, epoxy | PA6, PA66, PBT | Glass fiber PA66, high-temp PA |
| Metal corrosion | Moderate | Low | Minimal (polymeric network) |
| Cost-effectiveness | Most economical | Medium | High performance/premium |
| Typical loading for UL-94 V-0 | 20% (TPU) | 20-30% | 18-25% (PA66 GF30) |
| Parameter | Assessment |
|---|---|
| GHS Classification | Non-hazardous substance |
| Signal Word | WARNING (only for mechanical dust) |
| Pictogram | GHS07 (Irritant) |
| H320 | Causes eye irritation (mechanical friction) |
| H335 | May cause temporary respiratory tract irritation |
| P261 | Avoid breathing micronized dust aerosol |
| P284 | Use FFP2/FFP3 mask in inadequate ventilation |
| P305+P351+P338 | IF IN EYES: Rinse with physiological saline for 15 minutes |
Critical Regulatory Note: Melamine was classified as an SVHC under REACH in 2023 (Carc. 2, H351; STOT RE 2, H373). Melamine-based flame retardants that are polymeric (e.g., melamine polyphosphate) and not registered under REACH are not impacted by the classification of melamine as long as the threshold of 0.1% w/w residual melamine is met . Polymeric MPP-Poly products are considered under polymer exemption.
| Parameter | Value | Source/Note |
|---|---|---|
| Acute Oral LD50 (Rat) | > 2000 mg/kg | MP: OECD 401 |
| Acute Dermal LD50 (Rabbit) | > 2000 mg/kg | Chemically non-toxic class |
| Eye Irritation | Not irritating | OECD 405 |
| Skin Irritation | Not irritating | OECD 404 |
| Mutagenicity | Negative | Melamine phosphate genotoxicity tests negative |
| Carcinogenicity | Not classified | No human data; animal data based on melamine exposure |
MPP-Poly LD50 > 2000 mg/kg (rat) and no eye/skin irritation data are verified in supplier safety forms.
| Parameter | Value |
|---|---|
| Aquatic Toxicity LC50 (Danio rerio, 96h) | > 100 mg/L |
| Persistence | Slow assimilation to inert ammonium phosphate and nitrate derivatives in nature |
| Bioaccumulation | Log Kow < -2.3 (MPP-Poly, 20°C) ; low potential |
| PBT/vPvB | Not PBT |
For MPP-Poly: Log Kow < -2.3 at 20°C, low bioaccumulation potential, low in vivo toxicity (LD50 > 4000 mg/kg for polyphosphoric acid in rats) .
| Parameter | Information |
|---|---|
| Storage Temperature | +5°C to +35°C |
| Relative Humidity | <60% |
| Packaging | Original, unopened palletized bags |
| Avoid | Water-reactive chemicals, strong alkaline agents |
| Static Protection | Earthing/bonding required in pneumatic transfer lines |
| Shelf Life | 24 months (under proper conditions) |
MP is stable if maintained in original bags in a dry place at room temperature. Handle in compliance with good industrial practice, avoiding dust formation .
| Exposure | Action |
|---|---|
| Inhalation | Move to fresh air; provide 100% oxygen in respiratory distress, consult doctor |
| Skin | Remove contaminated clothing; wash with plenty of lukewarm water and neutral soap |
| Eyes | Do not rub; rinse thoroughly with eye wash solution or sterile water |
| Ingestion | If conscious, give 200-300 ml water with activated charcoal; do not induce vomiting, await medical intervention |
| Parameter | Information |
|---|---|
| Extinguishing Media | Water fog, alcohol-resistant foam, CO₂, ABC dry chemical powder |
| Thermal Decomposition (>350°C) | CO, CO₂, ammonia, NOx, P₂O₅ aerosols; no halogen gases |
| Firefighter Equipment | Positive-pressure SCBA + EN 469 full protective clothing |
| Parameter | Information |
|---|---|
| Personal Protection | Antistatic coveralls, chemical-impermeable gloves, dust-tight goggles |
| Environmental Precautions | Prevent seepage into drains, streams, and groundwater with barriers |
| Cleaning | HEPA-filtered Ex-Proof vacuum or moisten with light water fog and transfer to sealed drums |
| Parameter | Value/Recommendation |
|---|---|
| OSHA PEL (Inert dust, TWA) | 5 mg/m³ (respirable), 15 mg/m³ (total) |
| Respiratory Protection | EN 149 FFP3 mask |
| Hand Protection | EN 374 nitrile-coated gloves (Permeation Class 6, >480 min) |
| Eye Protection | EN 166 fully enclosed panoramic goggles |
| Body Protection | Type 5/6 antistatic work coveralls |
| Parameter | Information |
|---|---|
| Chemical Stability | Thermodynamically stable within standard industrial limits |
| Conditions to Avoid | Excessive humidity fluctuations (hygroscopic caking), out-of-limit thermal exposure |
| Hazardous Decomposition Products | Only under pyrolytic conditions: phosphoric acid derivatives, nitrogen fumes |
| Parameter | Information |
|---|---|
| UN Number | None (not dangerous goods) |
| ADR/RID/IMDG/IATA | Not classified as dangerous goods |
| Packing Group | Not applicable |
| Marine Pollutant | No |
MP: ADR/RID not restricted . MPP: DOT/IATA not hazardous material .
| Region/Regulation | Status |
|---|---|
| ECHA REACH | MP: Actively registered ; MPP-Poly: Polymer exemption (not registered under REACH) |
| US TSCA | Listed |
| China IECSC | Listed |
| RoHS (2011/65/EU) | Fully compliant (heavy metal limits below thresholds) |
| SVHC (Melamine) | Products unaffected as long as free melamine < 0.1% w/w |
Disposal:
Waste should be disposed of in licensed high-temperature industrial incinerators in accordance with waste code 14 06 03 or non-hazardous chemical waste codes designated by local environmental regulations. Emptied packaging bags can be included in the recycling loop.
SUMMARY:
The melamine phosphate series plays a critical role in the polymer industry as halogen-free flame retardants. The thermal stability hierarchy (MP < MPP < MPP-Poly) dictates the use of each product in different polymer matrices:
MP: Economical solution for low-processing-temperature polyolefin and polyurethane systems (max ~250°C). Water solubility is highest (0.35 g/100ml) .
MPP: Balanced performance in medium-high temperature engineering plastics (PBT, PA6). Water solubility is low (375 mg/L), providing moisture resistance .
MPP-Poly: Superior hydrolytic stability and low metal corrosion in high-temperature applications such as glass fiber reinforced PA66.
CRITICAL WARNINGS:
THERMAL LIMIT: Do not process MP above 250°C; risk of decomposition and premature foaming. For high-temperature polymers (PA66 GF30), always use MPP or MPP-Poly .
MELAMINE REGULATORY: Ensure free melamine content of products is below 0.1% w/w; otherwise REACH SVHC notification obligations may arise .
STATIC RISK: Do not work without earthing in pneumatic transfer lines; dust explosion risk exists.
PROTECTION: Do not inhale micronized dust; use FFP3 mask, enclosed goggles, and nitrile gloves.
STORAGE: Moisture leads to caking and hydrolytic degradation; store in original packaging below 60% RH.
Disclaimer: This TDS/SDS is for informational purposes only and is based on available data. Product performance may vary depending on polymer matrix, processing conditions, and formulation. The user is solely responsible for determining the suitability of the product for their specific application and for complying with all applicable local, national, and international regulations. This document is not a substitute for the official SDS provided by the manufacturer.