Due to the price deviation of plastic boxes compared with traditional carton packaging, but with the country’s environmental protection and green requirements for the printing industry, the advantages of plastic boxes have become increasingly apparent. At present, the most widely used blister cylinders are infants and children. Industry, cosmetics, digital products, etc.
Material requirements for blister molding
1. Blister molding can only produce tea farmers with relatively uniform wall thickness (generally, the chamfer is slightly thinner), and cannot produce plastic products with very different wall thicknesses.
2. The wall thickness of blister molding is generally within the range of 1 to 2mm or thinner (the most commonly used thickness of blister packaging for small packages is 0.15 to 0.25mm)
3. The degree of stretch of blister molded products is subject to certain restrictions. The diameter and depth ratio of blister molded plastic containers is generally not more than 1, and in extreme cases not more than 1.5.
4. The dimensional accuracy of blister molding is poor, and the relative error is generally more than one percent.
Blister gloss refers to the degree of specular reflection on the surface of the plastic box, expressed as a percentage. The higher the gloss of the blister, the more the surface can reflect light like a mirror, and the brighter the appearance. In fact, in addition to specular reflection on the plastic surface, there is also diffuse reflection, which reduces the gloss of the plastic box. The high-gloss plastic box raw materials, the brighter the ink color of the printed product, and the better the visual effect of the ink color. It can be said that the smoother the raw material of the plastic box, the higher the gloss, and the higher the gloss of the printed color. The gloss and smoothness of blister materials are closely related, but gloss is not smoothness. The glossy surface of blister materials is not necessarily a smooth surface. From the perspective of the gloss characteristics of blister materials, it is of practical significance to select suitable blister materials for printing according to the characteristics of the printed parts. For books and periodicals whose layout is mainly written, it is advisable to choose paper with average glossiness to avoid reflections and make the eyes look at for a long time without fatigue. However, for the printing plate-based layout, it is advisable to choose high-gloss PVC, PET, PP materials to make the ink color of the printed product uniform, thick, bright and pleasing to the eye.
High-density polyethylene is a white powder granular product, non-toxic and tasteless, with a density in the range of 0.940～0.976 g/cm3; crystallinity is 80%～90%, softening point is 125～135℃, and the use temperature can reach 100 ℃; hardness, tensile strength and creep are better than low-density polyethylene; abrasion resistance, electrical insulation, toughness and cold resistance are all better, but slightly worse than low-density insulation; good chemical stability, At room temperature, it is insoluble in any organic solvents, resistant to corrosion by acids, alkalis and various salts; the film has low permeability to water vapor and air, and low water absorption; poor aging resistance, and environmental cracking resistance is not as good as low-density polymer Ethylene, especially thermal oxidation will reduce its performance, so the resin needs to be added with antioxidants and ultraviolet absorbers to improve this deficiency. The high-density polyethylene film has a lower heat distortion temperature under stress, which should be paid attention to when applying it.
[Basic characteristics] High-density polyethylene is an opaque white wax-like material with a specific gravity lighter than water and a specific gravity of 0.941~0.960. It is soft and tough, but slightly harder than LDPE, and slightly stretchable, non-toxic and tasteless. Most of the plastic materials are extracted from some oils. The most familiar PC material is extracted from petroleum. When the PC material is burned, it has a rotten odor of flowers and fruits, with carbon-head molecules. ABS is Extracted from coal, ABS will be soot-like when it is burned out, without foaming; POM is extracted from natural gas
The plastic material HDPE is a non-polar thermoplastic resin with high crystallinity. High-density polyethylene is non-toxic, tasteless, and odorless white particles with a melting point of about 130°C and a relative density of 0.941 to 0.960. It has good heat resistance and cold resistance, good chemical stability, high rigidity and toughness, and good mechanical strength. Dielectric properties and environmental stress cracking resistance are also good. The melting temperature is 220~260℃. For materials with larger molecules, it is recommended that the melting temperature range is between 200 and 250°C.