EVA有哪些用途？(What are EVAs used for?)
EVA樹脂是乙烯-醋酸乙烯共聚物，一般醋酸乙烯（VA）含量在5%～40%。與聚乙烯相比，EVA由于在分子鏈中引入了醋酸乙烯單體，從而降低了高結晶度，提高了柔韌性、抗沖擊性、填料相溶性和熱密封性能，被廣泛應用于發泡鞋料、功能性棚膜、包裝膜、熱熔膠、電線電纜及玩具等領域。一般來說，EVA樹脂的性能主要取決于分子鏈上醋酸乙烯的含量。
發泡鞋材
鞋材是我國EVA樹脂最主要的應用領域。在鞋材使用的EVA樹脂中，醋酸乙烯含量一般在15%～22%。由于EVA樹脂共混發泡制品具有柔軟、彈性好、耐化學腐蝕等性能，因此被廣泛應用于中高檔旅游鞋、登山鞋、拖鞋、涼鞋的鞋底和內飾材料中。另外，這種材料還用于隔音板、體操墊和密封材領域。
薄膜
EVA薄膜的主要用途是生產功能性棚膜。功能性棚膜具有較高的耐候、防霧滴和保溫性能，由于聚乙烯不具有極性，即使添加一定量的防霧滴劑，其防霧滴性能也只能維持2個月左右；而添加一定量EVA樹脂制成的棚膜，不僅具有較高的透光率，而且防霧滴性能也有較大提高，一般可超過4個月。另外，EVA還可用于生產包裝膜、醫用膜、層壓膜、鑄造膜等。
電線電纜
隨著計算機及網絡工程的不斷發展，出于對機房安全的考慮，人們越來越多地使用無鹵阻燃電纜和硅烷交聯電纜。由于EVA樹脂具有良好的填料包容性和可交聯性，因此在無鹵阻燃電纜、半導體屏蔽電纜和二步法硅烷交聯電纜中使用較多。另外，EVA樹脂還被應用于制作一些特殊電纜的護套。在電線電纜中使用的EVA 樹脂，醋酸乙烯含量一般在12%～24%。
EVA resin is ethylene-vinyl acetate copolymer, generally vinyl acetate (VA) content is 5%~40%.Compared with polyethylene, EVA is widely used in foamed shoe materials, functional shed films, packaging films, hot melt adhesives, wires and cables and toys due to the introduction of vinyl acetate monomer in the molecular chain, thereby reducing high crystallinity, improving flexibility, impact resistance, filler compatibility and heat sealing performance.In general, the performance of EVA resin mainly depends on the content of vinyl acetate on the molecular chain.
Foamed shoe material:
Shoe material is the most important application field of EVA resin in China.In the EVA resin used in shoe materials, the content of vinyl acetate is generally 15%~22%.Because EVA resin blended foam products have softness, good elasticity, chemical corrosion resistance and other properties, they are widely used in the sole and interior materials of medium and high-end tourist shoes, hiking shoes, slippers and sandals.The material is also used in acoustic panels, gymnastics mats and sealants.
Membrane:
The main use of EVA film is the production of functional shed film.Functional shed film has high weather resistance, anti-fog droplet and heat preservation performance, because polyethylene does not have polarity, even if a certain amount of anti-fog drop agent is added, its anti-fog drop performance can only be maintained for about 2 months; The shed film made by adding a certain amount of EVA resin not only has a high light transmittance, but also greatly improves the anti-fog droplet performance, generally more than 4 months.In addition, EVA can also be used to produce packaging film, medical film, laminated film, casting film, etc.
Wire and cable:
With the continuous development of computer and network engineering, halogen-free flame retardant cables and silane cross-linked cables are increasingly used for the safety of computer rooms.Because EVA resin has good filler inclusiveness and crosslinkability, it is widely used in halogen-free flame retardant cables, semiconductor shielded cables and two-step silane crosslinked cables.In addition, EVA resin is also used to make some special cable sheaths. EVA resin used in wire and cable, vinyl acetate content is generally 12%~24%.
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