EVA plastic raw materials science and technology
EVA (ethylene-vinyl acetate copolymer) plastic raw materials, English abbreviation: EVA, refers to the ethylene-vinyl acetate copolymer. Technical Specification Code: 1314 CAS No.: 24937-78-8 Molecular Formula: (C2H4)x.(C4H6O2)y.
EVA material is a kind of daily life is more common in a class of midsole material, with it made of finished products with good softness, shockproof, anti-skid, strong pressure resistance, such as our common EVA slippers, cotton shoes, EVA cell phone protective cover, EVA ipad protective cover and so on.
Polymerization methods with high pressure body polymerization (for plastics), solution polymerization (PVC processing aids), emulsion polymerization (adhesives), suspension polymerization. Emulsion polymerization is used when the content of vinyl acetate (VA) is higher than 30%, and high-pressure body polymerization is used when the content of vinyl acetate is low.
EVA characteristics
Stability: good chemical stability, aging resistance, ozone resistance.
Water resistance: closed cell structure, non-absorbent, moisture-proof, good water resistance.
Corrosion resistance: resistant to seawater, grease, acid, alkali and other chemicals, anti-bacterial, non-toxic, odorless, non-polluting.
Processability: no joints, and easy to hot press, cutting, gluing, laminating and other processing.
Anti-vibration: high resilience and tensile strength, high toughness, good anti-vibration, cushioning performance.
Thermal insulation: heat insulation, cold insulation and low temperature performance is excellent, can be resistant to cold and exposure to the sun.
Sound insulation: closed cell, sound insulation effect is good.
EVA (ethylene vinyl acetate copolymer) application areas:
1, ethylene vinyl acetate content of 5% ~ 10% of EVA products for elastic films and so on;
2, ethylene vinyl acetate content of 20 ~ 28% of EVA, mainly used for hot melt adhesives and coating products;
3, ethylene vinyl acetate content of 5% ~ 45%, the main products are films (including agricultural films) and sheets, injection molding, molding products, foam products, hot melt adhesives, etc..
(1) Foamed shoe materials. Shoe material is the most important application area of EVA resin in China. In the EVA resin used in shoe materials, the vinyl acetate content is generally 15% to 22%. Due to the EVA resin co-blended foam products with soft, flexible, chemical resistance and other properties, it is widely used in medium and high-grade traveling shoes, hiking shoes, slippers, sandals, soles and interior materials. In addition, this material is also used in the field of sound insulation board, gymnastic mat and sealing material.
(2) Film: The main use of EVA film is to produce functional shed film. Functional shed film has a high degree of weather resistance, anti-dripping and thermal insulation properties, due to polyethylene does not have polarity, even if a certain amount of anti-dripping agent, its anti-dripping performance can only be maintained for about 2 months.
And add a certain amount of EVA resin made of shed film, not only has a high light transmission rate, and anti-fog droplet performance has been greatly improved, generally more than 4 months. In addition, EVA can also be used for the production of packaging film, medical film, laminating film, casting film and so on.
(3) wire and cable. With the continuous development of computer and network engineering, out of consideration for the safety of the computer room, people are increasingly using halogen-free flame retardant cables and silane cross-linked cables. As EVA resin has good filler inclusive and crosslinkable, it is used more in halogen-free flame retardant cables, semiconductor shielded cables and two-step silane cross-linked cables.
In addition, EVA resin is also used to make the sheath of some special cables. EVA resin used in wire and cable, vinyl acetate content is generally 12% to 24%.
(4) toys, EVA resin also has more applications in toys, such as children's wheels, seat cushions and so on.
(5) Hot melt adhesive. With EVA resin as the main component of the hot melt adhesive, due to the solvent-free, non-polluting and high safety, very suitable for automated assembly line production, so it is widely used in book wireless binding, furniture sealing, automobile and household appliances assembly, shoe making, carpet coating and metal anti-corrosion coating.