Introduction of specific content of eva in plastics

Plastics can be seen everywhere in our daily life, such as plastic film, plastic rubber shoes, plastic toys and so on. , a wide range of uses, the consumption of plastic products in the market is also very large. The use of some characteristics of plastics has brought great convenience to our lives. Today, Bian Xiao introduces a kind of plastic-plastic eva to you. It may not sound familiar, but it has a wide range of applications, especially in the footwear industry, which is used to produce travel shoes and sandals.

brief introduction

Ethylene-vinyl acetate polymer, EVA for short. Generally, the content of vinyl acetate (VA) is 5%-40%. Compared with polyethylene (PE), EVA is widely used in foam shoes, functional shed films, packaging molds, hot melt adhesives, wires and cables, toys and other fields because of the introduction of vinyl acetate monomer in the molecular chain, which reduces the high crystallinity and improves the toughness, impact resistance, filler compatibility and heat sealing performance.

characteristic

1, EVA with vinyl acetate content below 5%, the main products are film, wire and cable, LDPE modifier, adhesive and so on.

2. The content of vinyl acetate is 5%~ 10%? EVA products include elastic films.

3. EVA with vinyl acetate content of 20~28% is mainly used for hot melt adhesives and coated products; EVA is made of LLDPE (linear low density polyethylene) and acetic acid (VA).

Polymerization method of EVA:

1, high pressure bulk polymerization? (plastic products)

2. Solution polymerization? (PVC processing aid)

3. Emulsion polymerization? (Adhesive products)

4. Suspension polymerization

Main factors affecting EVA performance:

1, melting Index? Melting index (MI).

2、VA%？ The melting index (MI) of acetic acid is constant. The higher the content of vinyl acetate (VA), the higher its elasticity, flexibility, compatibility and transparency.

3. When the content of VA is reduced, its performance is close to that of polyethylene (PE), its rigidity is increased, and its wear resistance and electrical insulation are improved. When the content of VA is constant, with the increase of MI, the softening point decreases, the processability and surface gloss increase, but the strength decreases. Otherwise, with the decrease of MI, the molecular weight will increase, and the impact resistance and environmental stress cracking resistance will improve.

Characteristics of EVA

It has good flexibility, similar to rubber elasticity, good flexibility, transparency and surface gloss at -50℃, good chemical stability, good aging resistance and ozone resistance, and is non-toxic. Good miscibility with filler, coloring and molding processability. The polarity of acetate increases elasticity and viscosity, but decreases crystallinity and electrical properties. It is soluble in hydrocarbons and petroleum.

application area

1. Widely used in foam shoes, functional shed films, packaging molds, hot melt adhesives, wires and cables and toys.

2. The content of vinyl acetate is 5%~ 10%? EVA products include elastic films.

3. EVA with vinyl acetate content of 20~28% is mainly used for hot melt adhesives and coated products;

4. The content of vinyl acetate is 5%~45%, and the main products are films (including agricultural films) and sheets, injection molded products, foamed products and hot melt adhesives.

The characteristics of plastic eva are mainly reflected in the different vinyl acetate content. The synthetic plastic eva products will be different with different vinyl acetate content. They can be made into elastic films, coated products and some foamed products, such as toys. Plastic eva has good elasticity and flexibility, and its transparency is also quite good. There are transparent tubes on the market, which are corrosion-resistant and insulated. Through the introduction of this article, I believe everyone will have a deeper understanding of plastic eva. Bian Xiao hopes that everyone will have a deeper understanding of plastic eva.

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