Balancing Cost, Performance, and Compliance: Antimony-Free Alternatives to Flame-Retardant ABS

Scaglione：The primary impact is uncertainty. In the mold processing stage, teams often cannot obtain complete Critical to Quality (CTQ) characteristics from the Original Equipment Manufacturer (OEM), leading to a cycle in quoting—new Requests for Quotation (RFQs), constantly adjusted assumptions, and repeated quoting. It is difficult for the work to convert into actual orders because no one can determine whether the OEM will approve material changes, nor is it clear what compromises they will accept in terms of fluidity, shrinkage rate, or appearance. This uncertainty is precisely the main reason for resource consumption.

Goble：At the original equipment manufacturer (OEM) level, there are almost no completely "directly replaceable" materials. For example, in certain projects, flame-retardant ABS containing ATO can still achieve stricter ratings in thin-wall applications—such as the UL 94 5VA standard at specific thicknesses—while alternative materials find it difficult to achieve this. This forces companies to make a choice: either modify the design or select higher-performance materials. Whichever path is chosen will increase time costs, re-certification costs, and overall expenditures.

Source: Formerra

Goble：Firstly, the wire and cable industry is highlighted because many compounds in this sector not only require a high amount of flame retardants but also have a large scale of usage. Secondly, the electronics and electrical industry, which widely uses engineering-grade styrenic materials and blends, is actively evaluating halogen-free solutions. As manufacturers continue to expand their range of halogen-free products, polyamide (PA, nylon) and polybutylene terephthalate (PBT) are also being considered. Additionally, considerations related to perfluoroalkyl substances (PFAS) complicate some projects since certain PFAS additives are used for dispersion purposes.

Scaglione：The home appliance and consumer electronics industry is taking proactive actions because the components of these products must meet safety rating requirements as well as aesthetic standards. Coating properties, glossiness, and color consistency are fundamental requirements, and any alternative materials must ensure flame retardancy while meeting these aesthetic criteria.

Scaglione：In suitable applications, antimony-free polyamide (PA) and antimony-free polyvinyl chloride (PVC) have become mature alternative options. However, each of these materials has specific processing considerations: for example, polyamide (PA) requires drying and degassing treatment, while polyvinyl chloride (PVC) requires attention to corrosion control and temperature control; moreover, appearance requirements may further narrow the range of options.

Goble：Flame-retardant PBT and flame-retardant polyethylene terephthalate (PET) perform reliably in many electrical applications, especially for companies that wish to retain the base polymer and only replace the flame-retardant system. In the polyolefin field, magnesium hydroxide and phosphorus-based flame-retardant pathways are common choices for antimony-free solutions, but special attention must be paid to the amount of flame retardant added, material flowability, and component structural design.

Goble：In injection molded parts, only minor adjustments to the mold are required for flame-retardant PC/ABS to replace most flame-retardant ABS. However, attention must still be paid to weld lines, venting effectiveness, and thickness requirements. In a few cases, it can also replace flame-retardant polypropylene (PP) or flame-retardant high-impact polystyrene (HIPS), but this is only applicable in scenarios where the design requires stricter tolerances, thinner wall thickness, or higher flame retardance and heat resistance, and where compromises in cost and density are reasonable. Some companies even choose pure PC materials as long as they meet specification requirements. Currently, companies are more willing to switch materials, making flame-retardant PC/ABS a practical transitional solution to avoid reliance on ATO in mass applications.

Scaglione：For most flame-retardant ABS projects, flame-retardant PC/ABS is the easiest upgrade option—it not only retains the original appearance, paintability, and molding characteristics but also enhances heat resistance and impact margin. Formerra has multiple supply channels and can provide natural color, black, UV-stabilized, and pre-colored products. However, it is not a universal solution: due to the effect of ATO, some flame-retardant ABS compounds can achieve higher flame-retardant ratings under the same thin-wall conditions. If components must meet specific ratings (such as UL 94 5VA) at a fixed thickness, structural design adjustments or other material categories may be required.

Scaglione：Small home appliance and consumer product companies are taking the most active actions, with frequent testing activities. We have found that manufacturers have a strong demand for samples, and some product lines are even struggling to maintain inventory. This indicates that the companies' evaluation scope is broad, but it also means that if a project requires specific colors or UV-stable formulations, it is advisable to submit requests as early as possible.

Goble：We are assisting several clients in advancing the switch from flame-retardant ABS to flame-retardant PC/ABS. At the same time, material switches within the same base polymer category are also underway—such as transitioning from flame-retardant PET or flame-retardant PBT to antimony-free versions, and similar switches are being promoted for flame-retardant polyamide (PA). These switches are less difficult because the base resin remains unchanged. In addition, economic factors are also a driving force: as the cost gap between traditional materials and alternative materials continues to narrow, the commercial threshold has become lower than ever.

Goble：Flame-retardant PC/ABS generally exhibits better heat resistance and impact resistance, especially in low-temperature environments. Its fluidity may be similar to that of flame-retardant ABS, but for components with complex structures or long flow paths, special attention should be paid to weld line strength and exhaust effectiveness. Additionally, flame-retardant PC/ABS must undergo drying treatment and must strictly comply with drying specifications.

Scaglione：The flame-retardant PC/ABS exhibits excellent appearance, particularly in terms of gloss and color depth. However, for very light colors, stricter compound control and standardized color management are required. As long as the surface pretreatment remains consistent, coating, printing, and marking processes can usually be directly applied. If the gate design and holding pressure parameters are adjusted according to the resin characteristics, its dimensional stability can be comparable to that of flame-retardant ABS.

Source: Formerra

Scaglione：There are three key issues that determine the choice of alternative paths:

Goble：The main limitation is that some flame-retardant ABS grades containing ATO can still achieve higher flame-retardant ratings than flame-retardant PC/ABS under thin-wall conditions. If the wall thickness is fixed, companies can only choose the following options: adjust the structural design, accept a lower rating within permissible limits, or opt for higher-performance material categories.

Goble：These materials have significant advantages in applications involving micro devices, thin-walled components, and high-temperature areas. Traditional flame-retardant composites may not pass the glow wire test or UL 94 standards without increasing the wall thickness, which can lead to increased weight and affect cooling efficiency. In such scenarios, intrinsic flame-retardant resins can meet standard requirements while maintaining or even reducing wall thickness. However, in large-scale applications, flame-retardant PC/ABS is still almost the preferred choice.

Scaglione：Additionally, these materials can also meet regulatory compliance requirements in different regions. The trade-offs lie in color (usually amber or neutral), higher processing temperatures, and special demands on supply chain planning. The decision to use such materials is often related to "value density"—when the functionality of the component and compliance risks are sufficient to justify the cost of the resin, it can solve multiple problems at once.

Scaglione：These regulations have accelerated the evaluation process for alternative materials. Even if traditional flame retardant solutions remain compliant on a technical level, customers are choosing halogen-free or antimony-free materials as standard solutions for projects aimed at the European market to avoid the need for re-certification in the future.

At the same time, the documentation requirements have become more stringent. The project requires explicit disclosure of the composition of the flame retardant system and all intentionally added substances. At the initial stages of evaluation, we ensure that candidate materials comply with relevant European testing standards (such as the Glow Wire Test and the Comparative Tracking Index Test) to prevent unexpected issues later on.

Goble：In the North American market, cost fluctuations are the initial triggering factor. However, once companies understand the testing requirements and regulatory framework, many opt to uniformly adopt antimony-free materials within performance allowances to avoid subsequent re-validation. Compared to previous cycles, companies now have a stronger proactive response awareness — if it can be avoided, no one wants to undergo two rounds of certification.

Scaglione：Our material combinations offer both depth and breadth, providing multiple material solutions for the same objective. Whether it's PC/ABS, ABS modified materials, PBT, PET, polyamide (PA), polyvinyl chloride (PVC), or intrinsic flame-retardant materials, we can provide them all and match each solution with regional standards, thickness requirements, and appearance criteria. For example, if a candidate material fails the glow wire test or does not meet color requirements, we can directly switch to other material categories or flame-retardant systems without having to restart the entire screening process.

In addition, we will address practical issues such as drying requirements, exhaust guidance, coating and adhesion testing, color control, etc., to ensure that the test conditions are consistent with production conditions, thereby reducing unexpected situations and speeding up the Production Part Approval Process (PPAP) or similar certification processes.

Goble：In simple terms, our services go beyond recommending materials. We develop sampling plans, provide processing guidance, and identify alternative supply sources where possible. Additionally, we can match each candidate grade and component thickness with regional standards such as UL 94, International Electrotechnical Commission (IEC) 60695, Glow-Wire, Comparative Tracking Index (CTI), Relative Thermal Index (RTI), and Federal Motor Vehicle Safety Standard 302 (FMVSS 302), allowing customers to avoid guessing which antimony-free solution will retain their existing certifications. Ultimately, this model reduces process cycles and shortens the cycle from quotation to part validation.