The Usage of EVA material

 The Usage of EVA Material

EVA resin is an ethylene-vinyl acetate copolymer, and the vinyl acetate (VA) content is generally between 5% and 40%. Compared with polyethylene, EVA has a reduced high crystallinity and improved flexibility, impact resistance, filler compatibility, and heat-sealing performance due to the introduction of vinyl acetate monomers into the molecular chain. It is widely used in fields such as foamed shoe materials, functional greenhouse films, packaging films, hot-melt adhesives, wires and cables, and toys. Generally speaking, the performance of EVA resin mainly depends on the vinyl acetate content in the molecular chain. In 2001, the market consumption of EVA resin in China was approximately 290 kt. With the development of China's shoe-making industry and the increasing use of functional greenhouse films, the demand for EVA resin in China will continue to increase year by year.

(1) Foamed shoe materials Shoe materials are the most important application area for EVA resin in China. In the EVA resin used for shoe materials, the vinyl acetate content is generally between 15% and 22%. Since the EVA resin blended foamed products have properties such as softness, good elasticity, and chemical corrosion resistance, they are widely used in the soles and interior materials of mid - to high - end travel shoes, mountaineering shoes, slippers, and sandals. In addition, this material is also used in the fields of sound - insulation boards, gymnastic mats, and sealing materials. Shunde and Zhongshan in Guangdong, Jinjiang and Quanzhou in Fujian, and Wenzhou in Zhejiang are the main shoe - producing bases in China, consuming a large amount of EVA resin products every year. In 1999, the foamed shoe materials and shock - absorbing fields in China consumed approximately 150 kt of EVA resin in total.

(2) Films The main use of EVA films is to produce functional greenhouse films. Functional greenhouse films have high weather resistance, anti - fogging, and heat - preservation properties. Since polyethylene is non - polar, even if a certain amount of anti - fogging agent is added, its anti - fogging performance can only last for about two months. However, the greenhouse film made by adding a certain amount of EVA resin not only has high light transmittance but also has greatly improved anti - fogging performance, generally exceeding four months. In addition, EVA can also be used to produce packaging films, medical films, laminated films, casting films, etc. In 1999, there were more than 50 enterprises in China processing films using EVA resin. In 1999, China produced a total of 800 kt of greenhouse films, among which 220 kt were functional greenhouse films, consuming about 30 kt of EVA resin. Coupled with the fields of packaging films and medical films, China consumed a total of 37 kt of EVA resin in the film field.

(3) Wires and cables With the continuous development of computer and network engineering, considering the safety of computer rooms, people are increasingly using halogen - free flame - retardant cables and silane - crosslinked cables. Due to the good filler inclusiveness and cross - linkability of EVA resin, it is widely used in halogen - free flame - retardant cables, semiconductor shielding cables, and two - step silane - crosslinked cables. In addition, EVA resin is also used to make the sheaths of some special cables. In the EVA resin used for wires and cables, the vinyl acetate content is generally between 12% and 24%. In 1999, the wire and cable industry consumed approximately 6,000 t of EVA in total.

(4) Toys EVA resin is also widely used in toys, such as baby carriage wheels and seat cushions. China's toy processing industry has developed rapidly, with production concentrated in coastal areas such as Dongguan, Shenzhen, and Shantou, mainly for export and external processing. It is estimated that these manufacturers consume approximately 5,000 t of EVA resin every year, and the grades used are basically the same as those for shoe materials.