The process for enhancing the gloss of PVC baseballs

Raw material selection and blending
Raw material purity and type: High-purity PVC resin is selected. Raw materials with low impurity content can reduce surface defects caused by impurities during processing, making the surface of the baseball smoother and facilitating the improvement of gloss. At the same time, select the appropriate type of PVC based on the performance requirements of the baseball, such as suspension PVC resin, which has uniform particles and good processing performance, and is conducive to forming a smooth surface.
Additive optimization: Add an appropriate amount of lubricants, such as calcium stearate and zinc stearate, to the PVC formula. Lubricants can form a lubricating film between the PVC melt and the processing equipment, reducing friction and making the melt flow more smoothly. As a result, the surface of the baseball becomes flatter and smoother, and its gloss is enhanced. In addition, a small amount of brightener can be added. The brightener molecules can form a uniform film on the surface of the baseball, increasing light reflection and enhancing the gloss.
Forming process control
Injection molding temperature and pressure: Precisely control the temperature and pressure parameters of the injection molding machine. Excessively high injection molding temperatures can cause PVC materials to decompose, resulting in defects such as bubbles and black spots, which affect the surface gloss. If the temperature is too low, it will cause poor fluidity of the material, uneven filling, and problems such as flow marks and weld marks on the surface. Generally speaking, the injection molding temperature should be controlled within an appropriate range based on the characteristics of the PVC material and the size of the baseball. Meanwhile, an appropriate injection pressure can ensure that the PVC melt fully fills the mold cavity, avoiding problems such as material shortage due to insufficient pressure or flash caused by excessive pressure, making the surface of the baseball flatter and enhancing its gloss.
Mold design and maintenance: The design of molds has a significant impact on the gloss of baseball. The surface roughness of the mold cavity should be low, generally below Ra0.8μm, so that the PVC melt can form a smooth surface during the molding process. In addition, the exhaust system of the mold should be designed reasonably to ensure that the gas inside the mold can be discharged in time during the injection molding process, avoiding defects such as pores and bubbles on the surface of the baseball caused by gas residue. Regular cleaning and maintenance of the mold should be carried out to remove dirt, rust and other contaminants on its surface, keep the mold in good condition and also help improve the luster of the baseball.
Post-treatment process
Polishing and grinding: For PVC baseballs after injection molding, polishing and grinding treatment can be carried out. First, use coarse sandpaper to initially sand the surface of the baseball to remove burrs, flash and other defects. Then, gradually use fine sandpaper for fine grinding to make the surface smoother. Finally, use a polishing wheel and polishing paste to polish the surface of the baseball. The speed of the polishing wheel and the amount of polishing paste should be adjusted according to the material and surface condition of the baseball to achieve the best luster effect.
Coating treatment: Applying a transparent waterproof and wear-resistant coating on the surface of a baseball not only enhances its water resistance and wear resistance but also increases its gloss. The coating materials can be selected from polyurethane, acrylic, etc. These coatings have good adhesion and gloss. The coating methods can include spraying, dipping, etc. During the coating process, the thickness and uniformity of the coating should be controlled to avoid phenomena such as sagging and orange peel. After the coating is completed, place the baseball in an oven for drying and curing to ensure a tight bond between the coating and the baseball surface.