R915

R915 belongs to the halogen-free flame retardant category (official English category name Halogen-Free FR), with the official Chinese name "Transparent halogen-free flame retardant R915 dedicated to PET/PETG". The product brief reads verbatim: "1. Product name: transparent halogen-free organophosphorus flame retardant; 2. Model: R915; 3. Core component: polyol phosphate ester (additive-type organophosphorus system, no halogen, no heavy metals); 4. Product positioning: a high-efficiency halogen-free flame retardant developed specifically for highly transparent PET and PETG polyester materials, with no negative effect on the substrate's light transmittance or haze, no whitening, no yellowing and no migration during processing, perfectly suited to high-transparency articles such as transparent sheets, films, injection-molded optical parts and extruded profiles." (Data source: product handbook / official product data)

Halogen-free position (verbatim from source): the product name itself is "transparent halogen-free flame retardant"; the core component column states "no halogen, no heavy metals"; the core advantages state "pure organophosphorus system, free of chlorine, bromine and antimony, no halogenated toxic smoke on combustion, low smoke density"; there is also quantitative support: "halogen content: not detected (halogen-free)" and "meets the IEC 61249 halogen-free standard, Br+Cl<900ppm, total halogen<1500ppm". This product is a halogen-free model and is not within the scope of the low-halogen-content category. (Data source: product handbook / official product data)

Six core advantages (verbatim key points from the material): (1) ultra-high transparency retention — the molecular structure matches the polarity of polyester, and after addition the article shows no increase in haze and no loss of light transmittance; (2) high-temperature resistance suited to polyester processing — melting point 210℃, with a thermal stability range covering the normal processing temperatures of PET/PETG (240–280℃), and no decomposition, no smoke and no discoloration during extrusion, injection molding or casting; (3) halogen-free, environmentally friendly flame retardancy — pure organophosphorus system; (4) high-efficiency condensed-phase flame retardancy — phosphorus content 18%, and UL94 V-2/V-0 can be achieved at conventional dosage, with a significant increase in oxygen index (qualitative statement, no LOI figure); (5) no migration, no exudation — no blooming and no exudation under ambient conditions or double 85 damp-heat aging, and no oil mist on the article surface; (6) minimal effect on substrate properties — does not noticeably reduce the impact, tensile or flexural properties of PET/PETG, and does not impair printing, bonding or heat-sealing performance. (Data source: product handbook / official product data)

Mechanism (unified after correction on 2026-10-06 per the product specification): the handbook describes the system as a "pure organophosphorus system" and gives the mechanism entry as "high-efficiency condensed-phase flame retardancy", and in the processing entry states that "a small amount of phosphorus-nitrogen synergist can be added as needed to reduce the dosage, without affecting transparency throughout" (optional synergistic pathway, not the main system); the official mechanism field has been corrected accordingly to "pure organophosphorus system · high-efficiency condensed-phase flame retardancy + PET compatibility" (in the original "phosphorus-nitrogen synergy + PET compatibility", "phosphorus-nitrogen synergy" was a main-system statement and conflicted with the handbook's "pure organophosphorus system"; this has been corrected). Note: the page for this model contains no mention of "dripping", and this page does not carry over the dripping-property label of other models. (Data source: product handbook / official product data)

• High transparency retention — "no negative effect on the substrate's light transmittance or haze"; the optical comparison page contrasts "conventional flame-retardant PET · hazing · whitening · rainbow streaks" with "R915 flame-retardant PET · optical grade · ultimate clarity". The material describes transparency entirely qualitatively and gives no percentage figures.
• High-temperature processing — melting point 210℃, initial thermal decomposition temperature ≥260℃; the handbook gives a barrel temperature of 240–275℃ and the page gives a safe processing window of 240-280℃, and the two figures coexist (see the reading note in Section 3).
• Halogen-free and environmentally friendly — halogen content not detected; meets the IEC 61249 halogen-free standard (Br+Cl<900ppm, total halogen<1500ppm); statements on RoHS 2.0 and REACH SVHC compliance are given in the use, storage and transport section.
• No migration, no exudation — "a high-molecular-weight polyol phosphate ester structure; no blooming and no exudation under ambient conditions or double 85 damp-heat aging, and no oil mist on the article surface" (test duration and acceptance criteria not given).
• Minimal effect on the substrate — "does not noticeably reduce the impact, tensile or flexural properties of PET/PETG, and does not impair printing, bonding or heat-sealing performance" (qualitative statement).
• Additive type, does not participate in copolymerization — the remarks column reads verbatim: "This product is an additive-type flame retardant and does not participate in polyester copolymerization".

Composition and flame-retardant route: the core component is polyol phosphate ester (additive-type organophosphorus system, no halogen, no heavy metals); the phosphorus content is 18%, and the material labels it "high-efficiency condensed-phase flame retardancy" and states that UL94 V-2 / V-0 flame retardant ratings and a significant increase in oxygen index can be achieved at conventional dosage (no LOI figure). (Data source: product handbook / official product data)

Transparency mechanism: the material records this as "the molecular structure matches the polarity of polyester" — after addition the article shows no increase in haze and no loss of light transmittance, and the finished product is highly transparent with no whitening, hazing or rainbow streaks. All of this is qualitative; the material provides no comparison of transparency data against other similar models under the same test conditions, and this page makes no ranking. (Data source: product handbook / official product data)

Processing stability: melting point 210℃, initial thermal decomposition temperature ≥260℃, and the thermal stability range covers the normal processing temperatures of PET/PETG; the material states that there is no decomposition, no smoke and no discoloration during extrusion, injection molding or casting, and warns: "protracted hold at temperatures above 290℃ is prohibited, to avoid slight thermal degradation and yellowing of the flame retardant". The support for no migration and no exudation is the high-molecular-weight polyol phosphate ester structure. (Data source: product handbook / official product data)

1. Premixing — high-speed mixing of powder and pelletsMix R915 with PET/PETG pellets at high speed for 5–8min, then feed the uniformly mixed material to the machine; alternatively, first make a PET/PETG flame retardant masterbatch at 20%–30% concentration, which is easier to use and gives better dispersion.
2. Substrate preparation — drying to control moistureDry the PET/PETG substrate in advance at 120℃ for 4–6h to a moisture content of ≤0.03%, to prevent hydrolytic whitening during processing.
3. Shaping — low-shear, temperature-controlled processingUse a low-shear screw designed for polyester to avoid excessive shear causing reduced light transmittance; extrusion / injection barrel temperature 240–275℃, die / mold temperature 60–90℃; protracted hold at temperatures above 290℃ is prohibited.
4. Achieving flame retardancy — additive-type organophosphorus systemAdditive type, does not participate in polyester copolymerization; the dosage is set according to the target rating and thickness (V-2: 1.5mm 1%–2%; V-0: 1.0–1.5mm 2%–4%), and a small amount of phosphorus-nitrogen synergist can be added as needed to reduce the dosage.

The key physical and chemical specification table in the product handbook (including the test standard column) is reproduced verbatim below, cross-checking against the official product data and the values rendered on the page. The data are typical factory values; the page notes that a COA test report is supplied with each batch; a small-scale trial is recommended before bulk use.

Reading notes: (1) The test standard column (phosphorus elemental analysis, DSC, TGA, IEC 61249-2-21, etc.) is as listed in the original handbook table; (2) two processing-temperature figures coexist — the handbook's "barrel 240–275℃" and the page's "safe processing window 240-280℃"; the two are presented side by side and no choice is made on the customer's behalf, with the technical documents supplied with the goods prevailing; (3) "significant increase in oxygen index" is a qualitative statement; this model's page gives no LOI figure. (Data source: product handbook / official product data)

The recommended addition ratios are divided into two tiers by target rating and thickness (verbatim from the documents); the reduction path is to combine with a small amount of a phosphorus-nitrogen synergist as needed. The basis of the denominator is not stated in the documents (whether relative to resin mass or total system mass is not indicated); this page notes it as it stands.

Feeding and mixing key points: high-speed stirring pre-mix of powder and pellets for 5–8min; a masterbatch at 20%–30% concentration may be prepared first (better dispersion, more convenient to use). The dosage is slightly adjusted with the target rating, part thickness, equipment and process, and the synergist system — the documents explicitly recommend a small-scale trial in advance to determine the optimal formulation.

To be verified: (1) the basis of the denominator is not stated (relative to resin mass / total system mass); (2) the test bars, thickness, testing organization and report number, and LOI value for UL94 V-2 / V-0 — not provided in the documents; (3) all of the above are values recorded in the documents; for the actual formulation, please determine it according to the results of a small-scale trial.

The applicable substrates are PET (homopolymer PET, modified PET) and PETG copolyester, with no effect on transparency; four typical application categories (verbatim from the documents). Item by item below:

Transparent PET/PETG injection-molded parts

Lighting housings, transparent electronic enclosures, cosmetic packaging, instrument windows.

Extruded transparent sheet / board

Advertising light-transmitting panels, decorative transparent boards, equipment protective panels.

Cast PET film

High-transparency flame-retardant packaging film, optical protective film.

Transparent flame-retardant polyester pipes and profiles

Transparent flame-retardant polyester pipes, profiles, 3D printing PETG filament.

Process compatibility

Conventional extrusion, injection molding, casting; low-shear screw dedicated to polyester; drying / pre-mixing / optional masterbatch route; the page describes a four-step standard process that ensures the best balance between light transmittance and flame-retardant performance.

Masterbatch-side alignment (with an explicit source)

The official data state that "M915 internally uses R915, a transparent halogen-free flame retardant dedicated to PET/PETG"; the masterbatch brochure lists M915 as a transparent halogen-free flame-retardant masterbatch for PETG (its addition ratio of 6%-10%, processing temperature <280℃, UL94 V-0, etc. are the masterbatch's own specifications and are not interchangeable with the dosage of this model).

Field issues & application examples (as recorded in the source material)

Three selection boundaries on the flame retardant side for the transparency direction (divided by substrate, transparency level, and target data; all three are halogen-free grades):

Reading notes: (1) For the quantitative transparency comparison among the three, the data give no same-condition data — so no ranking of "which is more transparent" can be made; this page truthfully states that "the data do not clearly distinguish them"; (2) The naming relationship among the designations R912 / R912B / R915 is not explained in the data and is not interpreted; (3) Three sentences on the selection boundaries: for high-transparency / optical grade with a substrate within PET / PETG, take this grade; if TPU is involved or semi-transparency is acceptable, take R912; if only PET is used and V-0 and LOI figures are the direct target, take R912B. (4) The reference columns are the original text of their respective data; values are not transposed between them. (Data source: product handbook / official product data)

The three groups of points — processing technology and dosage, environmental compliance, and packaging/storage/transport — are taken item by item from the recorded data.

The data on this page come from two types of materials and can be traced item by item:

• Product handbook: the entire technical data page for this grade (product introduction / key physicochemical index table / six core advantages / applicable substrates and applications / processing technology and dosage / compounding operation points / environmental compliance / packaging, storage, and transport / safety notes / remarks); the contents line and the product overview section; the corresponding page in the flame retardant series booklet.
• Official product data: all fields for this grade (name, category, positioning, description, mechanism, applications, specifications, main components, recommended dosage); the flame retardant series entries (slogan, description, signature model); page-level copy (optical comparison table, thermal processing temperature zones, UL94 matrix, four-step process card, compliance and packaging section) and the site Q&A wording.

Not covered by the source material (not written on this page — to be added later)

• Mechanism field: corrected according to the product specification as of 2026-10-06 (formerly "phosphorus-nitrogen synergy + PET compatibility" → "pure organophosphorus system · high-efficiency condensed-phase flame retardancy + PET compatibility"; "phosphorus-nitrogen synergist" remains an optional sentence "can be added as needed") — this item is closed (decided, effective from 2026-10-06).
• Coexisting upper processing-window limits (240–275℃ vs 240-280℃) — for a unified specification, defer to the technical documents supplied with the goods.
• Quantified transparency (this grade has no light transmittance / haze percentage points; no same-condition comparison data with other grades in the same batch).
• Dosage denominator basis (relative to resin / total system mass) — not stated in the data.
• UL94 specimens, thickness, testing organization and report numbers, and LOI value; RoHS / REACH declarations of conformity and report numbers — not provided in the data.
• The test duration and criteria for "no blooming and no exudation after dual-85 damp-heat aging", and the quantified mechanical retention — not provided in the data.