2012年7月12日星期四

The function of EVA in thermoplastic road marking paint


EVA (ethylene-vinyl acetate copolymer) applied in road line construction as a component of road marking paint,especially thermoplastic road marking paint.
EVA resin is characteristic of good flexibility, the elasticity as rubber, under conditions below -50 ℃will still be able to have good flexiblity, transparency, and good surface gloss, good chemical stability, and strong aging resistance and ozone resistance, non-toxic. And easy to mixed with the packing, dye and mould informing process.
VAC (vinyl acetate copolymer) played a great role in the EVA resin's characteristics for its content, molecular weight and melt index. When the molt index (MI) is fixed, increase the content of VAC , its flexibility, softness, compatibility, transparency and so on also will be improved. When reducing the VAC content, the feature is similar to polyethylene, improved in rigidity, wear resistance and electric insulation. If in a definite VAC content , the melt index increased, the softening point will drop, moulding processing and surface gloss improve, but rigidity will decline. Otherwise, lower the MI with molecular weight increasing, impact resistance and environmental stress cracking performance is improved. The polarity of acetate moiety increased theflexibility and viscosity of EVA, crystallinity and electrical performance drop, making EVA soluble in hydrocarbon solvents and oil.
EVA, Vinyl acetate content of 20 to 28 percents, is mainly used for hot melt adhesives and paint products, as thermoplastic road marking paint.

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