Views:2 Author:Site Editor Publish Time: 2021-06-18 Origin:Site
EVA composites have been widely used in our life, such as EVA schoolbag, EVA earphone bag, EVA kit, EVA computer bag, EVA emergency bag, and so on. So do you know Eva compounding? Today, this article will introduce some basic common senses about EVA compounding.
This paper will start from the following three aspects:
What are the characteristics of the EVA compound?
What is the use of EVA compound?
How to process EVA compound?
EVA resin is characterized by good flexibility, rubber-like elasticity and good flexibility at - 50 ℃. In addition, it has good transparency, surface gloss, chemical stability, and so on. It is closely related to the content, molecular weight and melt index of vinyl acetate. When the melt index (MI) is fixed and the content of vinyl acetate (VAC) is increased, the elasticity, softness, solubility and transparency of VAC are also improved. When the content of VAC decreases, the properties are close to polyethylene, the rigidity increases, the wear resistance and electrical insulation improve. If the content of VAC is constant and the melt index increases, the softening point decreases, the processability and surface gloss improve, but the strength decreases.
EVA resin is widely used. In general, the main products of EVA with vinyl acetate content less than 5% are film, wire and cable, LDPE modifier, adhesive, etc. EVA products with 5% ~ 10% vinyl acetate content are elastic films. EVA with vinyl acetate content of 20 ~ 28% is mainly used for hot-melt adhesives and coating products. Vinyl acetate content is 5% ~ 45%, the main products are film (including agricultural film) and sheet, injection molding, molding products, foam products, hot-melt adhesives, etc. For example:
(1) Film, sheet and laminated products.
(2) Industrial products: power wire insulation leather bag, household appliances accessories, window sealing materials, etc.
(3) Daily groceries: sporting goods, toys, cushion, strap, sealed container cover, EVA rubber football, etc.
(4) Auto parts: shock absorber, fender, interior and exterior decoration parts, etc.
(5) Foam products: pressure foam, foam plastic slippers, sandals, building materials, etc. Injection foam has a variety of industrial parts, women's soles, hot-melt adhesives.
1. Injection molding. It is OK to use Eva compounding injection equipment used in general PE or PP. The lower limit of molding temperature is to maintain a certain fluidity, while the upper limit is to prevent EVA thermal decomposition. The thermal decomposition temperature is about 229 ~ 230 ℃. In general, the material temperature should be controlled from 170 ℃ to 200 ℃.
2. Vacuum forming. Generally, it can be formed by cooling the mold at low temperatures.
3. Blow molding film. Because of the low melting point of EVA, the cooling of material must be considered. In addition, the addition of a lubricant should be considered.
4. Foaming forming. When foaming, attention should be paid to the adjustment of the amount of foaming agent. Its foamed products are characterized by elasticity, lightweight, toughness and low shrinkage.
The above is about the basic knowledge of EVA compound, Nanjing Haisi provides high-quality EVA extruder products, welcome to buy.