1. Food-grade plastic masterbatches need to meet specific safety standards, such as those of the U.S. Food and Drug Administration (FDA) or the European Toy Safety Directive.
2. These standards usually include strict restrictions on the chemical composition of plastic raw materials, heavy metal content, use of plasticizers, etc.
3. Masterbatch manufacturers must ensure that their products do not release harmful substances in applications such as contact with food or toys.
4. Masterbatches that meet food-grade standards usually need to go through a series of testing and certification processes to prove their safety and reliability.
5. When selecting masterbatches, carefully check the material safety data sheet (MSDS) and related certificates provided by the supplier to confirm that they meet the required standards.
1. Three core types of food-grade masterbatches
Organic masterbatches: balance between high concentration and color expression
Features: With organic pigments as the core, bright colors and good dispersibility, suitable for resin substrates such as PP and PE.
Typical applications: PP lunch boxes, PET beverage bottles, yogurt cups, etc.
Technical advantages: High-concentration formula (pigment content up to 50%) can reduce the amount of addition and reduce the risk of migration; adding antioxidants can improve weather resistance and extend the service life of containers.
Inorganic masterbatch: representative of high temperature resistance and chemical stability
Features: Mainly based on inorganic pigments such as titanium dioxide and iron oxide, heat resistance > 280℃, suitable for high-temperature injection molding process.
Typical applications: microwave heating lunch boxes, high-temperature resistant bottle caps, etc. For example, PA inorganic masterbatch can maintain color stability in a 280℃ hot runner system and pass the SGS heavy metal migration test.
Technical advantages: Inorganic pigment particle size <1μm, avoiding surface defects of containers due to excessively large particles; adding silane coupling agent can improve compatibility with the substrate.
Functional masterbatch: dual upgrade of safety and function
Antistatic masterbatch: adding antistatic agent to PET bottle blank to avoid dust adsorption due to static electricity during packaging, which meets the standards of food contact materials.
Antibacterial masterbatch: through silver ion or zinc oxide composite technology, it inhibits bacterial growth and is suitable for fresh-keeping boxes, tableware, etc.
2. Food-grade masterbatch safety certification system
International standards:
FDA 21 CFR 178.3297: stipulates the migration limit of heavy metals (lead, cadmium, mercury, etc.) in masterbatch, for example, the migration of lead is <0.5ppm.
European Union (EU) No 10/2011: simulate food contact conditions (40℃, 10 days), and detect the total migration amount (OML) in masterbatch <10mg/dm².
Domestic standards:
GB 4806.7-2023: Clearly define the sensory and physical and chemical indicators of masterbatches, such as potassium permanganate consumption ≤10mg/kg, heavy metal migration ≤1mg/kg.
Detection method: Use gas chromatography-mass spectrometry (GC-MS) to detect plasticizer residues such as phthalates to ensure that no toxic substances are released.
III. Process adaptability: closed-loop control from raw materials to finished products
Substrate matching:
PE masterbatch: Suitable for blow molding bottles, films, etc., dispersants (such as EBS) need to be added to avoid melt fracture.
PS masterbatch: For transparent yogurt cups, transparent masterbatch (pigment particle size <0.3μm) must be used to ensure transmittance >85%.
Processing temperature control:
The decomposition temperature of the masterbatch must be higher than the processing temperature by more than 20°C. For example, the PP processing temperature is 200-230°C, and a masterbatch with a decomposition temperature >250°C needs to be selected.
Storage and transportation pollution prevention:
Masterbatch needs to be packaged in aluminum foil to avoid light-induced pigment degradation; the storage environment humidity is controlled below 40% RH to prevent moisture absorption and agglomeration.
