Food-grade Plastic Injection Molding Requirements

Raw Material Management Requirements

Only brand-new virgin plastic materials dedicated for food contact are allowed in food-grade injection molding. Recycled materials, sprue and runner scraps or miscellaneous materials are prohibited throughout production, and industrial-grade plastic materials shall never be mixed in. All incoming raw materials are stored in exclusive designated areas, fully separated from ordinary plastic materials and various chemical additives. The storage areas are kept dry, clean and well ventilated to prevent dust accumulation, moisture absorption, oil contamination and odor adsorption. All raw materials must go through pre-drying treatment before use. The temperature and duration are set according to material characteristics to fully remove internal moisture. This avoids material hydrolysis and decomposition under high molding temperature, which would otherwise produce harmful low-molecular substances. A dedicated material usage rule is implemented. Food-grade materials of different types and colors are scheduled and produced separately. Complete cleaning of equipment is mandatory when switching materials or colors to eliminate cross-contamination, so as to secure product safety from the source.

Equipment and Mold Management Requirements

Specialized injection molding equipment must be adopted for food-contact plastic products. Sharing production lines with equipment for industrial plastics and non-food-grade products is forbidden. All parts that come into direct contact with molten plastic, including screws, barrels and nozzles, are made of food-grade stainless steel. These components feature smooth surfaces with excellent corrosion resistance, free from rust, carbon deposits and residual dead corners. A regular cleaning schedule is established. Comprehensive wiping and cleaning are conducted before startup and after shutdown every day. When changing production batches or raw materials, special food-grade purging compounds are used to thoroughly clean screws and barrels to remove residual old materials and carbonized impurities. All lubrication points are filled with food-grade lubricants and equipped with reliable sealing structures to prevent lubricant leakage from contaminating molten materials and finished products.

Molds are custom-made exclusively for food-grade production. Mold cavities and runners are highly polished to achieve smooth surfaces without burrs, pits or cleaning dead corners, which effectively prevents material and dust buildup as well as bacterial growth. Mold designs optimize the flow path of molten plastic and eliminate material retention zones to lower the risk of carbonization under high temperature. Molds are fully disassembled, cleaned and disinfected after each production batch. Water stains and residual impurities are removed completely before dust-proof storage. Regular polishing, repair and anti-corrosion maintenance are carried out to maintain stable and clean working conditions.

Production Environment and Operator Requirements

The production workshop maintains a closed and clean environment with stable temperature, humidity, clean air and no peculiar smell. Physical partition is applied to divide the workshop into raw material storage area, injection molding area and finished product packaging area. Pedestrian passages and logistics passages are separated to avoid cross interference. Regular cleaning and disinfection are performed throughout the workshop. Floors and operating platforms are wiped and dedusted daily, and air sterilization is conducted periodically to inhibit the breeding of dust, pests and microorganisms.

All on-site operators are required to wear full sets of dust-proof work clothes, masks, gloves, caps and shoes and keep the outfits neat at all times. Every operator receives professional training on hygiene operation specifications and must follow the rules strictly. Direct hand contact with molten plastic, semi-finished and finished products is prohibited. Personnel suffering from infectious diseases or skin diseases are not permitted to engage in the production of food-contact products. Regular physical examinations are arranged for all staff to ensure compliance with hygiene standards.

Injection Molding Process Requirements

Low-temperature and stable processing is adopted for food-grade plastic injection molding. The retention time of molten plastic under high temperature is strictly controlled to prevent thermal decomposition and harmful substance generation. Barrel and mold temperatures are set precisely based on material properties. Overheating is avoided to stop material aging, carbonization and contaminant precipitation. Key process parameters including material drying standards, injection pressure, holding time and cooling duration are standardized and kept unchanged during production. Random parameter adjustment is not allowed.

Injection speed is maintained stable and uniform to ensure complete product molding without bubbles, sink marks or cracks. Residual internal stress is minimized to prevent material precipitation and cracking during subsequent use. Secondary processing such as spraying, grinding and repairing is not allowed. All food-contact finished products are kept in their original molding state to rule out secondary pollution.

Finished Product Control and Traceability Requirements

Finished products must have clean and smooth surfaces, free from black spots, impurities, scorch marks, color deviation, burrs and peculiar odors. Sampling inspection is conducted regularly during production to check appearance and contamination. Non-conforming products are isolated and scrapped immediately to prevent mixing with qualified goods. Sorting and packaging of finished products are completed in a clean environment. Packaging materials are kept clean, sterile and odorless, and products are sealed promptly after packaging to avoid pollution from external dust and microorganisms.

A complete batch traceability system is established. Detailed records of raw material batches, production equipment, process parameters, operators and production time are kept for each batch of products. Records of equipment cleaning, process parameters and workshop disinfection are fully filed. Comprehensive standardized management guarantees the production safety and stable quality of every batch of food-contact plastic products.