Environmentally friendly synergistic flame retardantPhosphorus-silicon system · aluminium phosphosilicate · smoke suppression and charring · replaces antimony trioxide
A white crystalline powder, odourless and non-toxic; under the microscope it shows a fibrous/needle-like morphology. Together with halogenated flame retardants it acts synergistically, replacing 50–70% of antimony trioxide at a 1:1 ratio (up to 100% in PVC), lowering flame-retardant cost and saving antimony resources.
- 🌱 Environmentally friendly P-Si system · REACH / 2002/95/EC
- 🤝 Halogen synergy · smoke suppression and charring
- ⚖️ 1:1 replacement of 50–70% Sb₂O₃
- 🔬 Needle-like whiskers · fine and loose texture
- Main ingredient
- Aluminium phosphosilicate
- Chemical formula
- Al(SiO2)PO4·2H2O
- Density
- 0 – 0 g/cm³
- Melting point
- 0 – 0 ℃
Charring · oxygen barrier · smoke suppression cross-section
The burning surface chars rapidly; the char layer blocks oxygen from entering and suppresses smoke escaping — the physical picture of synergistic flame retardancy.
Aluminium phosphosilicate · needle-like whiskers
R218 is a white crystalline powder, odourless and non-toxic; under the microscope it appears fibrous or needle-like, with a fine and loose texture. It is an environmentally friendly phosphorus-silicon flame retardant and complies with EU 2002/95/EC, REACH and similar environmental regulations.
Partial replacement of antimony trioxide
In plastics halogenated flame-retardant systems it is mainly used for the partial replacement of antimony trioxide: in PP/PE systems it replaces 50–70% at a 1:1 ratio, with flame retardancy better than Sb₂O₃ used alone with brominated compounds; in PVC systems it can replace 100% — significantly lowering flame-retardant cost and saving antimony resources.
Used with phosphorus / intumescent systems
In halogen-free flame-retardant systems R218 is used together with phosphorus-based and intumescent flame retardants, delivering rapid charring, oxygen blocking and smoke suppression.
Antimony replacement console · 1:1 replacement ratio
Choose a system and drag the replacement ratio: green is the R218 share, grey is the retained Sb₂O₃ share.
Flame-retardant system
Physical and chemical properties
Typical properties of a mineral flame retardant; chemical reaction boundaries are listed separately.
⚠ Chemical reaction boundaries (do not contact)
It reacts with hydrofluoric acid and hot concentrated alkali: with hydrofluoric acid it forms silicon tetrafluoride and phosphorus compounds; with hot concentrated alkali it forms silicates, meta-aluminates and metaphosphoric acid. Keep storage and use away from these media.
Packing and storage · occupational safety · sample request
Submit the form opposite and a technical consultant will contact you within 24 hours to arrange a sample.
Packing and storage
⚠ Occupational safety and handling notes
- Wear protective gloves, a mask and goggles; avoid inhaling dust and direct contact with skin and eyes;
- In case of eye contact rinse immediately with plenty of water and seek medical attention; for skin contact wash thoroughly with soapy water;
- Aluminium phosphosilicate is non-toxic, but inhaling large amounts of dust irritates the respiratory system and long-term exposure may cause pneumoconiosis — keep the workplace well ventilated and, where necessary, install effective dust extraction.
01Product positioning
R218 belongs to the "flame retardant synergist" category (English: FR Synergist), official full name "Flame Retardant Synergist R218"; the page title is "Eco-friendly Synergistic Flame Retardant"; it belongs to the flame retardant series. Its role in the formulation is that of a synergistic component—partial replacement of antimony trioxide, not a halogen-free main flame retardant. (Data source: product handbook / official product data)
Catalog line verbatim: "R218: Flame Retardant Synergist (Partial Replacement of Antimony Trioxide)"; company profile list sentence verbatim: "Flame Retardant Synergist (Partial Replacement of Antimony Trioxide): R218"; page title verbatim: "Eco-friendly Synergistic Flame Retardant R218". (Data source: product handbook / official product data)
Detail page subtitle verbatim: "Phosphorus-silicon system · Phosphorus-substituted aluminum silicate · Smoke suppression and char formation · Replacement of antimony trioxide"; above-the-fold description: "White crystalline powder, odorless and non-toxic; under the microscope it appears in fibrous/needle-like form. Synergistic with halogenated flame retardants, can replace 50–70% of the antimony trioxide at a 1:1 ratio (PVC can be 100%), reducing flame-retardant costs and conserving antimony resources." (Data source: official product data)
Halogen status note: neither this product's name nor its documentation characterizes it as "halogen-free" or "low-halogen"; the word "halogen" appears only in descriptions of the formulation systems ("synergistic with halogenated flame retardants", "in plastic halogenated flame-retardant systems"), and is not self-verification of this product's halogen content. On this page the halogen status is treated as "not applicable", and no halogen content claim is made for this product. (Data source: product handbook / official product data)
- Antimony replacement synergy—partial replacement of antimony trioxide (Sb₂O₃) in halogenated formulations: in PP/PE systems, replacement of 50% to 70% at a 1:1 ratio; in PVC systems, 100% replacement possible.
- Char formation · oxygen barrier · smoke suppression—used in halogen-free flame-retardant systems together with phosphorus-based and intumescent flame retardants, it "performs the functions of rapid char formation, oxygen barrier and smoke suppression".
- Effect comparison (source sentence)—in PP/PE scenarios, "its flame-retardant effect is better than the combination of antimony trioxide and brominated flame retardants used alone".
- Environmental compliance—"the product meets the requirements of EU environmental regulations such as 2002/95/EC and REACH".
- Stable physical properties—relatively high melting point (usually in the range of 1300 – 1600℃); pH 6.5-7, with a certain resistance to most acids and alkalis at room temperature.
- Before-use note—white crystalline powder, slightly soluble in water and common organic solvents; storage and use must keep it away from hydrofluoric acid and hot concentrated alkalis.
02Formulation system & mechanism of action
Composition and system: main component phosphorus-substituted aluminum silicate (chemical formula Al(SiO₂ )PO₄ ·2H₂ O); form is white crystalline powder, odorless and non-toxic, appearing under the microscope in fibrous or needle-like form, with a fine and loose texture. System characterization verbatim: "This product is an eco-friendly phosphorus-silicon flame retardant, with a marked synergistic effect with halogenated flame retardants, while also exhibiting excellent smoke suppression and char-forming performance." (Data source: product handbook / official product data)
Mechanism layer 1 · antimony replacement synergy (the defining statement of this grade) verbatim: "In plastic halogenated flame-retardant systems, R218 is mainly used for partial replacement of antimony trioxide... it can replace 50% to 70% of the antimony trioxide at a 1:1 ratio, thereby significantly reducing flame-retardant costs and conserving antimony resources." The official mechanism field records "antimony replacement synergy". (Data source: product handbook / official product data)
Mechanism layer 2 · char formation, oxygen barrier and smoke suppression verbatim: "In halogen-free flame-retardant systems, R218 can be used together with phosphorus-based and intumescent flame retardants, performing the functions of rapid char formation, oxygen barrier and smoke suppression." The two pathways differ in their basis and their action: halogenated formulations perform "replacement" (reducing the Sb₂O₃ dosage), while halogen-free systems perform "pairing" (use together with phosphorus-based and intumescent flame retardants)—they cannot be cross-calculated or mutually converted. (Data source: product handbook / official product data)
- Replacement — 1:1 equal-weight replacement of antimony trioxidePP/PE systems: replacement of 50% to 70% of the antimony trioxide at a 1:1 ratio; PVC systems: 100% replacement possible. The basis is the number of parts of Sb₂O₃ being replaced.
- Synergy — synergistic effect with halogenated flame retardantsThe documentation records that this synergy "has a marked effect"; in PP/PE scenarios, "its flame-retardant effect is better than the combination of antimony trioxide and brominated flame retardants used alone".
- Char formation and oxygen barrier — synergy in halogen-free systemsUsed together with phosphorus-based and intumescent flame retardants: rapid char formation, oxygen barrier.
- Smoke suppression — a simultaneous char-forming behavior"while also exhibiting excellent smoke suppression and char-forming performance"; smoke suppression is one of its three functions in halogen-free systems.
03Key parameters
The physicochemical items recorded in the handbook and official product data are transcribed as follows (the official layer and handbook layer are verbatim identical for each item, differing only in spacing; chemical formula and melting point are transcribed per the existing main component / chemical formula / melting point fields). The values in the table are as recorded in the source materials.
| Item | Value / description |
|---|---|
| Main component | Phosphorus-substituted aluminum silicate |
| Main component | Phosphorus-substituted aluminum silicate |
| Chemical formula | Al(SiO₂ )PO₄ ·2H₂ O |
| Melting point | Relatively high, typically in the range of 1300 – 1600℃ |
| Density | approx. 2.6 – 3.2 g/cm³ |
| Chemical stability | Slightly soluble in water and general organic solvents; pH 6.5-7, with a certain tolerance to most acids and bases at room temperature |
| Incompatible media (safety boundary) | Can react chemically with hydrofluoric acid and hot concentrated alkali: reacts with hydrofluoric acid to form silicon tetrafluoride, phosphorus and other substances, and with hot concentrated alkali to form silicates, metaaluminates and metaphosphoric acid. Keep away from the above media during storage and use |
| Appearance / form | White crystalline powder, odorless, non-toxic; under the microscope it appears in fibrous or needle-like form, fine and loose in texture |
| Packaging and shelf life | Woven bag packaging with an inner polyethylene plastic liner, net weight 25 kg per bag (packaging specifications customizable); under normal storage conditions the product shelf life is generally 2 years |
Reading notes: ① Density and melting point are at the typical magnitude of the mineral system (phosphorus-substituted aluminum silicate), differing in magnitude from the organic phosphorus liquid / lithium salt powder branches of the same series, and cannot be compared with one another; ② The pH and "can react chemically with hydrofluoric acid and hot concentrated alkali" items together constitute the chemical stability boundary — the latter is a safety boundary (two clearly defined incompatible media), not a performance indicator; ③ The source does not give moisture, particle size / fineness, whiteness, loss on ignition, quantitative water solubility, or test method columns; ④ The values in the table are as recorded in the source materials. (Data source: product handbook / official product data)
04Recommended dosage window
This grade has a special basis: the source gives a "substitution ratio", not a "dosage" — this grade's page has no dosage field. The basis of the substitution ratio is the parts of antimony trioxide being replaced (1:1 equal-amount substitution of 50%–70% of it), not "R218 as a percentage of the total resin / article weight".
| Scenario | Dosage | Conditions & notes |
|---|---|---|
| PP / PE system (halogenated formulation) | 1:1 substitution of 50% – 70% | Source wording: "can substitute 50% to 70% of the antimony trioxide at a 1:1 ratio, and its flame retardant effect is superior to using a combination of antimony trioxide and brominated flame retardants alone" |
| PVC system (halogenated formulation) | 100% substitution | Source verbatim: "can 100% substitute antimony trioxide" |
| Halogen-free flame retardant system | used in combination (ratio not given in the source) | Source verbatim: "R218 is usually used in combination with phosphorus-based and intumescent flame retardants, mainly exerting its advantages of rapid char formation, oxygen barrier and smoke suppression" |
The two formulation paths act differently: the halogenated formulation performs "substitution" — reducing the Sb₂O₃ dosage; the halogen-free system performs "combination" — working together with phosphorus-based and intumescent flame retardants. The two systems cannot be converted into one another, nor compared or interchanged with the dosages of other grades (such as 10%-20%, 1.5%-5%); this grade also has no "thickness–dosage" directional clause (the source makes no record regarding "thinner" or "thickness").
To be verified: ① The correspondence between flame retardant rating / oxygen index / smoke density after substitution, and the adjustment basis for the substitution ratio at different article thicknesses — not given in the source; ② The specific combination ratio windows with brominated flame retardants and with phosphorus-based / intumescent flame retardants — the source only writes "used in combination / used together", without giving ratio figures; ③ Several dosage fields and verification records in the official data layer do not correspond to this grade's data page, and have been handled per the source layer and not adopted; ④ All the above are as recorded in the source materials; for actual formulations please conduct small-sample verification with your own system.
05Applications
Applicable polymers (source verbatim): PE, PP, PVC, ABS, PBT, PET and various other flame retardant polymers; the two formulation paths are transcribed as follows.
- Halogenated flame retardant formulation (antimony substitution scenario)
- PP/PE system: 1:1 substitution of 50%–70% antimony trioxide; PVC system: can 100% substitute antimony trioxide — "thereby significantly reducing flame retardant costs and conserving antimony resources".
- Halogen-free flame retardant system
- Used in combination with phosphorus-based and intumescent flame retardants: "exerting its effects of rapid char formation, oxygen barrier and smoke suppression".
- Applicable polymers
- PE, PP, PVC, ABS, PBT, PET and various other flame retardant polymers.
- Official application tags
- PP/PE flame retardant system / PVC flame retardant system / halogen-free flame retardant system (three items transcribed).
- Relationship with the primary agent (grade-selection reading)
- This product addresses the "antimony cost and antimony resource" issue — it is the synergistic / antimony-reducing action within the formulation; the halogen-free flame retardant primary agent addresses the "imparting a flame retardant rating to the substrate" issue. The two are in a combination relationship (the source text itself says "used in combination" and "used together"), not a substitution relationship.
- Masterbatch aspect
- The source does not record any correspondence between this product and any masterbatch product — this page does not infer one.
Field issues & application examples (as recorded in the source material)
| Field issue | What the source material states |
|---|---|
| Is R218 a halogen-free flame retardant? | No. Across five layers the source consistently characterizes this product as a "synergist": the category field "flame retardant synergist", the page title "eco-friendly synergistic flame retardant", the catalog line "flame retardant synergist (partial substitution of antimony trioxide)". It does not serve as a halogen-free flame retardant primary agent on its own, but is the antimony-replacing synergistic component in a formulation. |
| How does it substitute? How much? | PP/PE system: substitute 50% to 70% of the antimony trioxide at a 1:1 ratio; PVC system: can 100% substitute. The basis is the parts of antimony trioxide being replaced, not "a percentage of the total resin weight". |
| What is the effect after substitution? | Source wording: in the PP/PE scenario, "its flame retardant effect is superior to using a combination of antimony trioxide and brominated flame retardants alone". The quantified rating / oxygen index / smoke density comparison is not given in the source, and this page does not extrapolate. |
| What does it do in a halogen-free system? | It is used in combination with phosphorus-based and intumescent flame retardants, exerting rapid char formation, oxygen barrier and smoke suppression; the specific ratio window is not given in the source. |
06How it differs from related grades
Same-series comparison on the flame retardant side: the five halogen-free flame retardant main agents solve "imparting a flame retardant rating to the substrate", while this grade solves "the synergistic antimony-replacement action in the formulation" — different roles and different quantitative bases (main agent = addition level; this product = substitution ratio), and it is not merged into their column. The comparison is as follows:
| Grade | Role · Category | System | Dosage / substitution basis | Rating · Key points |
|---|---|---|---|---|
| R218 | Flame retardant synergist · partial replacement of antimony trioxide | Eco-friendly phosphorus-silicon system (phosphorus-substituted aluminum silicate) | Substitution ratio: PP/PE 1:1 replaces 50%–70%; PVC 100% replacement | Synergy with halogen systems; in halogen-free systems: char formation · oxygen barrier · smoke suppression |
| R911 | Halogen-free flame retardant (main agent) · PE thin products | Hindered amine compounds | Addition level 10%-20% | UL94 V-2 (films) / FV-2; the thinner the product, the more the addition level should be appropriately increased |
| R912 | Halogen-free flame retardant (main agent) · PET / PETG / TPU | Tris(xylene lithium carbonate) phosphate (organophosphorus lithium salt) | TPU 2%–7%; PETG / PET 1.5%–3% each (fine-tuned according to product thickness and rating) | UL94 V-2 / V-0 (with a reasonable formulation); light transmittance decreases by about 20% |
| R912B | Halogen-free flame retardant (main agent) · PET | Phosphorus-based + a small amount of nitrogen-based synergist | Reaches UL94 V-0 at an addition level of 1.5%-5% | LOI raised to above 38% |
| R915 | Halogen-free flame retardant (main agent) · transparent PET / PETG | Polyol phosphate (phosphorus content 18%) | UL94 V-2 (1.5mm): 1%–2%; UL94 V-0 (1.0–1.5mm): 2%–4% | High-transparency basis, halogen not detected; melting point 210℃ |
| R940 | Halogen-free flame retardant (main agent) · UV / PU reactive type | DOPO + phosphazene + HEMA | UV 15-30% (of total resin mass); PU 12-25% (of the polyol component) | Reactive type; total phosphorus content about 10.5% |
Reading notes: ① The five main agents are placed side by side in this table only for "role comparison" — the five are on an addition-level basis while this grade is on a substitution-ratio basis; the denominators differ, and no cross-level conversion is made; ② Being adjacent within the same booklet does not mean being the same category: this grade must not be read as a main agent on the basis of its number or position; ③ The five agents' respective directions, prohibitions and boundary clauses (such as thin-product restrictions and notes that they cannot be used in certain systems) belong to those agents' own terms and are not imported into this page; ④ Grade selection is always based on the official full name and the category field. (Data source: product handbook / official product data)
07Usage & storage
The following points are taken item by item from the source materials; items not listed in the materials are not drafted by us.
Substitution ratio (quoted as recorded)
- PP/PE system: substitute 50% to 70% of the antimony trioxide at a 1:1 ratio.
- PVC system: can replace 100% of the antimony trioxide.
- Halogen-free system: used in combination with phosphorus-based and intumescent flame retardants; the blending-ratio window is not given in the materials.
Packaging and storage
- Packaging: woven-bag packaging with an inner polyethylene plastic liner, net weight 25 kg per bag; packaging specifications can be customized according to customer requirements.
- Storage: store in a dry, well-ventilated warehouse; avoid moisture and rain; keep away from fire sources, heat sources and strong oxidizers.
- Shelf life: under normal storage conditions, the product's shelf life is generally 2 years.
Chemical stability boundaries (incompatible media)
- Slightly soluble in water and common organic solvents; pH 6.5-7; at room temperature it has a certain resistance to most acids and bases.
- It can react chemically with hydrofluoric acid and hot concentrated alkali (forming substances such as silicon tetrafluoride and phosphorus / silicates, meta-aluminates and metaphosphoric acid) — during storage and use, keep away from the above media.
Handling protection and occupational health
- Wear protective gloves, a mask and goggles; avoid inhaling dust and direct contact with skin and eyes.
- If the eyes are accidentally contacted, rinse immediately with plenty of clean water and seek medical attention promptly; if skin contact occurs, wash thoroughly with soapy water.
- Although phosphorus-substituted aluminum silicate is non-toxic, inhaling large amounts of its dust may irritate the respiratory system, and long-term exposure may also cause occupational diseases such as pneumoconiosis; the workplace should be kept well ventilated, and effective dust-removal equipment should be provided when necessary.
Safety & occupational health · 5
08FAQ
What role exactly does R218 play in a formulation?
Two paths: ① Halogen systems — partial replacement of antimony trioxide (PP/PE 1:1 replaces 50%–70%; PVC can be 100% replaced), reducing flame retardant cost and saving antimony resources; ② Halogen-free systems — used in combination with phosphorus-based and intumescent flame retardants, providing rapid char formation, oxygen barrier and smoke suppression.
How should the substitution ratio be read?
The basis is the parts of antimony trioxide being replaced: a 1:1 equal-amount replacement of 50%–70% of it (PP/PE system) or 100% (PVC system). It is not "the percentage of R218 in the total weight of resin / product" — the latter is not given in the materials, and this page does not draft it.
Is there data on the effect after substitution?
The materials describe this product qualitatively: for the PP/PE scenario they state "its flame retardant effect is superior to that of the combination of antimony trioxide and a brominated flame retardant used alone"; quantitative comparisons such as oxygen index / UL94 rating / smoke density / char yield are not given in the materials, and this page does not extrapolate.
Why can't it be used as a halogen-free flame retardant main agent?
Different roles: all five layers of the materials characterize it as a "synergist" (page title / catalog line / list sentence / body self-description / official category field). Its relationship with the main agent is one of combination — the main agent imparts a flame retardant rating to the substrate, while this product performs antimony-reducing synergy; the source text itself says "used in combination" and "used together".
What are the storage requirements?
A dry, well-ventilated warehouse; avoid moisture and rain; keep away from fire sources, heat sources and strong oxidizers; under normal storage conditions the shelf life is generally 2 years. During storage and use, keep away from the two incompatible media: hydrofluoric acid and hot concentrated alkali.
What about compliance?
The materials record that "the product complies with the requirements of EU environmental regulations such as 2002/95/EC and REACH"; document information such as the compliance report number is not given in the materials, and this page does not draft it.
AppendixData sources
The data on this page comes from two types of materials, traceable item by item:
- Product handbook: the full section of this grade's page (product introduction / five physical and chemical property items / main uses / packaging and storage / precautions); the catalog line and the list sentence in the company profile; the technical data pages of the individual grades in the same series (used for the comparison table).
- Official product data: all fields of this grade (name, category, positioning, description, mechanism, application, parameters, main components); the flame retardant series entry; the official detail-page copy.
Not covered by the source material (not written on this page — to be added later)
- Engineering support for the substitution ratio: the correspondence between the substitution and the flame retardant rating / oxygen index / smoke density, and the basis for adjusting the substitution ratio at different product thicknesses — not given in the materials.
- Blending-ratio window: the specific blending ratios with brominated flame retardants and with phosphorus-based / intumescent flame retardants — not given in the materials.
- Compliance document numbers: the compliance report numbers for 2002/95/EC and REACH, and the SVHC list version — the materials contain only a statement of compliance.
- Missing physical and chemical items: moisture / particle size (fineness) / whiteness / loss on ignition / quantitative water solubility / test method column — not listed.
- Cost and environmental benefits are stated qualitatively (reducing flame retardant cost, saving antimony resources); the reduction figures are not given — no extrapolation.
- Safety data (MSDS-type) entries, exposure limits, and packaging and transport compliance entries — not listed in the materials.