Compliance Requirements for Food-Contact Plastics in Injection Molding

Material compliance is the fundamental prerequisite for the injection molding of food-contact plastics, directly impacting the safety of food products and consumer health. With the increasing stringency of regulatory standards and technological advancements in the industry, compliance has evolved from mere indicator fulfillment to a comprehensive, full-chain management system. Based on current national standards and industry best practices, this document systematically outlines the core compliance requirements for materials used in the injection molding of food-contact plastics, providing precise technical guidance for manufacturers.

The core regulatory basis for evaluating the compliance of food-contact plastic materials in China is GB 4806.7-2023 National Food Safety Standard for Plastic Materials and Articles in Contact with Food, which was officially implemented on September 6, 2024. This standard integrates the previous separate standards for resins and products, significantly expanding the scope of application.

1.1 Key Applicable ProductsThe standard covers injection-molded articles primarily made from synthetic resins or bio-based polymers. Notably, it adds specific provisions for starch-based plastics (with a starch content ≥ 40%) and unvulcanized thermoplastic elastomers. This includes a wide range of products such as tableware, food containers, and packaging accessories commonly produced via injection molding.

1.2 Cross-Standard Synergy

Material compliance cannot be viewed in isolation; it must align with supporting standards. Additives used in the resins must adhere to GB 9685 and relevant announcements. Edible starch raw materials must comply with GB 31637, and modified starches must be among the varieties approved by GB 2760 and related announcements.

2.1 Basic Raw Material RequirementsResin raw materials must be listed in Appendix A of GB 4806.7-2023 or approved through relevant official announcements. Enterprises must verify compliance certificates and test reports during procurement. For starch-based plastics, there is a strict requirement that the starch used must be edible starch or modified starch, strictly prohibiting the incorporation of non-food-grade starch.

2.2 Critical Physicochemical LimitsPhysicochemical indicators are the cornerstone of material safety and must strictly adhere to the following industry-recognized limits:

2.3 Additive Usage SpecificationsAdditives must be selected from the list of permitted substances in GB 9685, and their usage amounts must be strictly controlled within the specified limits. A new regulatory requirement classifies plant fibers as additives, which now require specific authorization. For additives with potential health risks, such as Bisphenol A (BPA), the migration limit has been lowered to 0.05 mg/kg, and its use is prohibited in products intended for infants.

3.1 Procurement and Acceptance ControlEnterprises should establish a qualified supplier directory. During procurement, they must obtain quality inspection reports and compliance certificates, focusing on verifying resin names, CAS numbers, additive types, and dosages. The acceptance process requires batch sampling to inspect sensory indicators (normal color, no odor, no impurities) and key physicochemical indicators to ensure batch stability.

3.2 Process Compatibility and Material StabilityInjection molding parameters must be matched to the material's characteristics to prevent decomposition caused by improper processing. Specifically, strict control over melt temperature and residence time is necessary to avoid the release of hazardous substances due to resin degradation. Regarding the use of recycled materials, it must comply with specific standard requirements, with clear limits on the proportion of recycled content and applicable scenarios. Importantly, recycled materials are not permitted for use in food-contact products intended for infants.

3.3 Equipment and Environmental Sanitation

Surfaces of equipment that come into direct contact with the plastic melt, semi-finished products, or finished products must be made of compliant materials such as food-grade stainless steel (grade 06Cr19Ni10 or higher) or ceramics. The use of materials containing harmful substances like lead, cadmium, or phthalates is strictly prohibited. When changing raw material varieties or colors, a rigorous five-step cleaning process must be executed: purging, disassembly, scrubbing, rinsing, and drying. Cleaning validation must meet standards such as TOC ≤ 0.5 mg/L or a wipe test ≤ 0.1 g/m².

4.1 Expansion of Bio-Based MaterialsWith the trend toward green development, bio-based and biodegradable materials such as Polylactic Acid (PLA) are being increasingly adopted. Their compliance requires special attention to migration risks during the degradation process to ensure they meet core indicators like overall migration throughout their service life. For starch-based plastics, strict control of the starch content (≥ 40%) is mandatory. If the overall migration exceeds limits, it is necessary to determine the trichloromethane extractables according to GB 31604.8 to assess compliance.

4.2 Application of Low-Migration AdditivesThe industry is gradually adopting low-migration, high-performance additives. For example, new-generation clarifiers for polypropylene can reduce additive dosage while minimizing migration and blooming, thereby enhancing material compliance and processing compatibility. Such additives must undergo prior compliance verification to ensure they meet GB 9685 requirements.

4.3 Construction of Full-Chain Traceability SystemsCompliance requirements now extend to full-chain traceability. Enterprises must establish complete records tracking materials from procurement and production to delivery. These records should include raw material batches, test results, and process parameters to enable precise traceability in the event of a compliance issue.

The compliance requirements for food-contact plastic injection molding materials are centered on safety and grounded in national standards, spanning the entire lifecycle from raw material procurement to production processes and technological applications. Enterprises must accurately grasp core indicator limits, strengthen process controls, and proactively adapt to industry trends such as eco-friendly materials and low-migration technologies to achieve dual guarantees of compliant production and product safety. Looking ahead, as regulations and technology continue to advance, material compliance will become increasingly refined, driving the high-quality development of the industry.