Japan, EU REACH, Southeast Asia TISI, New Energy Aging Tests—How To Choose The Right Flame Retardant for Polyurethane Exports?

Japan, EU REACH, Southeast Asia TISI, New Energy Aging Tests

—How to Choose the Right Flame Retardant for Polyurethane Exports?

Factories that export their products often encounter this situation: although they have put a great deal of effort into developing domestic formulations and their products have passed flame-retardant testing, the requirements for flame retardants vary greatly among customers in different countries, leading to slow development progress or even the loss of projects. The regulatory logic governing flame retardants differs significantly across the EU, Southeast Asia, and the new energy vehicle markets; it cannot be simply summarized as “the EU is strict, Southeast Asia is lenient” or “reactive flame retardants are used for high-end products, while additive flame retardants are used for low-end products.”

Building insulation materials in the EU must meet the B-s1,d0 classification specified in EN 13501-1. For rigid polyurethane foam, this means it must pass the SBI single-body combustion test (EN 13823), and both smoke density (EN ISO 5659-2) and burning droplets (EN ISO 11925-2) must meet the required standards. Regarding flame retardants, halogenated flame retardants (such as TCEP and TDCPP) are explicitly restricted by the REACH SVHC Candidate List or the Restrictions Annex (Annex XVII) and must not be used. Red phosphorus flame retardants are not listed on the SVHC list themselves; however, it is important to note that industrial-grade red phosphorus products often contain trace amounts of yellow phosphorus impurities (<0.005%), and yellow phosphorus is included on the SVHC Candidate List. Therefore, red phosphorus flame retardants exported to the EU must use high-purity red phosphorus (yellow phosphorus content <0.001%) and be accompanied by a third-party test report.

Key Procedures for Engineers in EU Projects: Before finalizing the formulation, SBI preliminary testing and REACH SVHC screening must be completed to confirm that the yellow phosphorus impurity content in the red phosphorus raw material is less than 0.001%, and third-party test reports must be retained for customer review.

Southeast Asia is not a “regulatory vacuum.” Thailand’s TISI (Thai Industrial Standards Institute) has clear fire resistance rating requirements for building insulation materials, which are generally equivalent to Class A under ASTM E84 or Class B1 under GB 8624; Vietnam’s QCVN 06:2022 also includes flame-retardant requirements for insulation materials used in high-rise buildings. A common characteristic of these markets is that certification and testing resources are limited, so manufacturers tend to use formulations that have “passed domestic Class B1 testing” for direct export, rather than redeveloping them to meet local standards.

The competitiveness of red phosphorus flame retardants in this market stems from the cost advantage derived from their lower loading levels. Taking rigid foam for building insulation as an example, achieving a flame retardancy equivalent to Class B1 requires the addition of approximately 40 parts of aluminum hydroxide (based on 100 parts of polyether). At current market prices, the cost of flame retardant raw materials accounts for approximately 18–22% of the total raw material cost of the rigid foam; whereas the red phosphorus system requires only 12–14 parts, keeping the flame retardant cost at 8–12%. For small and medium-sized foam manufacturers with an annual production capacity of less than 5,000 metric tons, this cost difference directly determines the competitiveness of their quotes.

Yinsu’s paste-form red phosphorus composite flame retardant is well-suited for the Southeast Asian market for the following reasons: The product is a premixed paste, eliminating the need for customers to make additional investments in powder metering and dust collection equipment; packaging options of 25 kg or 200 kg per drum are suitable for small- to medium-volume purchases; and the paste maintains storage stability for over six months at ambient temperatures of 30–40°C, making it well-suited for warehouse conditions in Southeast Asia.

Key Operational Points for Engineers on Projects in Southeast Asia: Fine-tune formulations based on domestic B1-grade formulations, but confirm in advance whether local customers will accept the equivalence statement in the GB test report; prioritize paste-form products to avoid delays in production caused by the factory’s lack of powder-handling equipment.

The advantage of the phosphorus-nitrogen synergistic system in this scenario lies in its chemical stability. APP (ammonium polyphosphate) has a molecular structure consisting of polyphosphate chains and contains no ester bonds, making its hydrolytic stability significantly superior to that of phosphate esters; melamine derivatives (such as MPP) have a decomposition temperature above 250°C and do not volatilize during long-term thermal aging. After 1,000 hours of aging at 85°C and 85% RH, YinSu’s phosphorus-nitrogen blended flame retardants typically maintain an LOI retention rate of >90%, and the UL-94 V-0 rating remains unchanged.

Key Considerations for Engineers in New Energy Vehicle Projects: During the DV (Design Verification) phase, it is essential to include testing of flame retardancy retention after aging at 85°C/85% RH, rather than relying solely on initial UL-94 data; it is recommended to prioritize the use of phosphorus-nitrogen synergistic systems that do not contain ester bonds to avoid hydrolysis failure of liquid phosphate esters in long-term humid and hot environments.

• EU Projects: Complete SBI pre-testing and REACH SVHC screening before finalizing the formulation to confirm that the yellow phosphorus impurity content is <0.001%

• Southeast Asia Projects: Fine-tune formulations based on domestic Class B1 standards and confirm in advance whether local authorities accept equivalence declarations for GB test reports

• New Energy Vehicle Projects: Include flame retardancy retention testing after aging at 85°C/85% RH during the Design Verification (DV) phase; do not rely solely on initial UL-94 data

• General Principle: Paste-form products are more suitable for export than powders, as they reduce customers’ equipment retrofitting costs and dust handling burdens

About YinSu Flame Retardants

• Coated red phosphorus micropowder: Suitable for Class B1 formulations in the EU market for rigid foam; provides REACH compliance dossiers

• Paste-form red phosphorus composite flame retardant: Pre-mixed paste formulated to accommodate the equipment and storage conditions of small- to medium-sized factories in the Southeast Asian market

• Phosphorus-nitrogen synergistic system: Ester-bond-free, designed to meet the 85°C/85% RH aging requirements for new energy vehicle battery packs and charging station components

All three products support third-party testing, and supporting compliance documentation can be provided according to the specific regulatory requirements of the target market. We welcome technical teams from export-oriented manufacturers and compounding plants to contact us for samples or to discuss technical solutions.