2023-10-17
1. Definition
EVA is a Copolymer of Ethylene and acetic acid, Chinese chemical name: ethylene-vinyl Acetate copolymer, English chemical name: Ethylene Vinyl Acetate Copolymer. General vinyl acetate (VA) content in 5%-40%, compared with polyethylene (PE), EVA due to the introduction of vinyl acetate monomer in the molecular chain, thereby reducing the high degree of crystallization, improve toughness, impact resistance, filler phase compatibility and thermal sealing performance, is widely used in foam footwear, functional shed film, packaging mold, hot melt adhesive, wire and cable and toys and other fields. It is also widely used in the field of new energy, such as photovoltaic materials, solar cell adhesives and so on.
2. Characteristics
(1) EVA material has good softness, rubber-like elasticity, and still has good flexibility at -50℃.
(2) Transparency and surface gloss, good chemical stability, good anti-aging and ozone resistance, and non-toxic.
(3) EVA material is designed for processing and molding. Its shock resistance is better than traditional foam materials such as polystyrene (foam), and it can be cut and molded compared to shock-proof packaging.
(4) EVA material meets environmental requirements and is the best choice for export products.
(5) Because the density varies greatly, it can also be used in a wider range of applications.
Second, the definition of EVA packaging lining
1. Definition
EVA packaging lining, the name of the magic is used for iron boxes, paper gift boxes, whiteboard boxes, plastic boxes inside the lining. Mainly play a role in protecting the product, such as: U disk, jewelry, cutting tools, measuring tools, cutting tools, precision instruments, instrument box anti-rust packaging materials.
2. Classification
(1) In terms of different polyurethane foams, there are environmental protection coarse hole EVA, general EVA, food grade stainless steel odorless environmental protection EVA, fire safety EVA and antistatic EVA.
(2) In terms of lining strength, there are 25 degrees, 38 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, industrial commonly used foot pads are 38 degrees, 45 degrees, electronic internal accessories are generally 25-38 degrees.
(3) In terms of characteristics, there are general environmental protection EVA liners, fire safety EVA liners and antistatic EVA liners.
(4) In terms of tone, EVA packaging lining has gray and black EVA lining, milky EVA lining, colored EVA lining, white and black are commonly used in industry, and color is less.
Third, the production process of EVA packaging lining
Two molding methods for EVA packaging lining:
1, stamping molding: The stamped EVA lining is made with a knife die and then a small punching machine. If the thickness of the product is more than 3CM, it may make the four sides feel convex and convex, and the position with holes on the surface will have this phenomenon. In addition, the thickness of the stamped product should not be too thick, too thick will lead to the feeling that the position with holes will be concave.
2, engraving molding: The use of CNC computer engraving machine, one engraved EVA lining edge is straight. For example, if the thickness of EVA lining is 9CM, four sides can be carved out and are straight, but if the machine is pressed, the thickness of 9CM should be glued with two to three layers.
Four, the advantages of EVA packaging lining
(1) Water resistance: closed bubble structure, no water absorption, moisture resistance, good water resistance.
(2) Corrosion resistance: resistance to seawater, grease, acid, alkali and other chemicals corrosion, antibacterial.
(3) Easy processing: no joint, good toughness is easier to shape, and easy to hot pressing, cutting, gluing, laminating and other processing. High hardness accuracy, powerful function, practicability.
(4) Shock resistance: high resilience and tension resistance, strong toughness, it can absorb and disperse the external impact force through bending to achieve the buffering effect, with good shock buffering performance; Add hard high-density material, shock-proof material light toughness is good, compressive resistance and collision without fear of violence consignment.
(5) Thermal insulation: Excellent thermal insulation, thermal insulation, cold and low temperature performance, can withstand cold and exposure.
(6) Environmental protection: EVA foam raw materials non-toxic and tasteless processing, does not contain any harmful substances to the human body, no additives, degradable, environmentally friendly combustion, is a recyclable environmental protection materials, in line with the European Union's mandatory environmental requirements for product packaging, can be used for export.
Five, the application of EVA packaging lining
EVA lining packaging is widely used in jewelry, porcelain, toolbox, electronic products, instruments, gift boxes, toys, craft gifts, jewelry, cosmetics, medicine, hardware, wine, furniture, lighting and other sponge packaging fields.