For the formulation design of PVC plastic pallets for packaging products, the following points should be noted:
1) The formulations for soft and hard PVC products are different. Generally speaking, the dosage of plasticizers below 10PHR (PerHundredResin, representing the mass of the required 100 resin materials in the formula) is for hard PVC products; the dosage between 10 and 40PHR is for semi-hard PVC products; and the dosage above 40PHR is for soft PVC products.
2) Due to the thermosensitivity of PVC, no stabilizers are added in the formulation. In general, the dosage of stabilizers in PVC formulations is 5-8 PHR. If the dosage of stabilizers is too low, it can only prevent PVC from decomposing at the heat-melting temperature. However, if stabilizers are added, it will cause the heat-melting temperature to rise, resulting in poor heat-melting fluidity.
3) To enhance the melt processing performance of PVC, soluble melt processing additives should be added to the formulation. Practice has proved that for hard PVC products, without processing additives, they cannot be melted or molded; while for high-quality soft PVC products, without or with insufficient processing additives, processing is difficult. The processing additives for PVC are mainly composed of materials that have good compatibility with PVC acrylate resin (ACR), as well as chlorinated polyethylene (CPE), chlorosulfonated polyethylene, styrene polymers, MBS, ABS, etc. Note: The addition amount of processing additives should not be excessive. If it exceeds 12PHR, it may cause the melt viscosity to be too low and the extrusion force to be too small, resulting in inability to extrude. Generally, the addition amount of processing additives is 5-8PHR.
4) Polyvinyl chloride itself has no components, but its singularity is very significant. The requirement of the Food and Drug Administration of the United States (internationally recognized) is that when the content of vinyl chloride monomer (VCM) in polyvinyl chloride resin is lower than one ten-thousandth, it can be used for food, medicine, packaging, direct contact with food and medicine.
5) Polyvinyl chloride plastic trays have excellent transparency. The high transparency of polyvinyl chloride products should also be reflected in the formulation and additives to ensure good transparency of polyvinyl chloride resin.
