The material structure of high-toughness PVC baseball needs to be carried out from four aspects: base material selection, toughening system design, structural optimization and processing technology adaptation. The following is a specific analysis:
Selection of matrix materials
PVC itself is divided into two types: soft and hard. Soft PVC is prone to becoming brittle due to the presence of softeners and has poor preservation properties. Hard PVC does not contain softeners, has good flexibility, is easy to form, is not prone to brittleness, and is non-toxic, pollution-free, and has a long shelf life. Therefore, for high-toughness PVC baseball, hard PVC should be given priority as the base material to ensure that it has better initial toughness.
Design of toughening system
To achieve high toughness, toughening agents need to be introduced into the PVC matrix. For example, the addition of MBS resin (methyl methacrylate – butadiene-styrene copolymer) can significantly enhance the impact resistance of the material. MBS resin forms an island structure in PVC. When the material is subjected to external force impact, rubber phase particles can cause silver streaks and absorb energy, thereby preventing crack propagation. In addition, it is also advisable to consider adding toughening agents such as CPE (chlorinated polyethylene) and ACR (acrylate) to further enhance toughness through their synergistic effect.
Structural optimization
Multi-layer composite structure: A multi-layer composite design can be adopted, such as an outer layer of high-toughness PVC to provide impact resistance. The inner layer is a lightweight foaming layer, which reduces weight and enhances buffering performance. This structure not only ensures the durability of the baseball but also enhances the comfort of use.
Microcellular foaming technology: A uniformly distributed microcellular structure is formed in the PVC matrix through chemical foaming agents. Micropores can absorb part of the impact energy, reduce stress concentration, and thereby enhance the toughness of the material. Meanwhile, microcellular foaming can also reduce the weight of the baseball and improve its flight stability.
Processing technology adaptation
Injection molding temperature control: The injection molding temperature needs to be precisely controlled within the range of 170-190℃ to ensure that the PVC is fully plasticized and to avoid thermal decomposition. Excessively high temperatures can lead to the degradation of materials and reduce their toughness. If the temperature is too low, it may cause insufficient plasticization of the material, affecting the molding quality.
Mold design: The mold design needs to take into account the shape characteristics and force conditions of the baseball. For example, a streamlined design can be adopted to reduce stress concentration; Set up reasonable exhaust channels to avoid the formation of pore defects during the foaming process. In addition, the surface of the mold needs to be polished to reduce demolding resistance and improve the surface quality of the product.
Post-treatment process: Eliminate internal stress and enhance dimensional stability through heat setting treatment. For products with high surface hardness requirements, UV-cured coatings can be used to enhance wear resistance and protect the tough layer from damage.