Sinopec EVA

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Sinopec EVA

  • EVA and Polyvinyl Alcohol: Chemical and Physical Properties Analysis
    Feb 19, 2025
    🔬 At a molar fraction of 5% vinyl acetate, the mechanical properties of EVA (ethylene vinyl acetate copolymers) become very similar to those of soft PVC.EVA is flexible in its own right, which gives it a number of advantages, such as the disadvantage of avoiding the migration of plasticizers, which is the main reason for the gradual replacement of PVC.     💪 These copolymers have a higher modulus and better processing properties than typical elastomers and do not require vulcanization considerations. Polyvinyl alcohol (PVA 088-50 & PVA 2488) can be obtained by hydrolysis of polyvinyl acetate. Poly(vinyl alcohol) is an atactic cubic polymer but does not disrupt the lattice structure due to the small hydroxyl groups. Therefore, ester bases that are not sufficiently hydrolyzed reduce crystallinity and the number of intermolecular hydrogen bonds.   💧 Highly hydrolyzed poly(vinyl acetate) (containing fewer unhydrolyzed ester groups) has a higher crystallinity. As the degree of hydrolysis increases, the molecules become easily crystallized. If these molecules are not sufficiently dispersed before dissolution, hydrogen bonding will cause them to associate with each other. In order to achieve hydrolysis levels above 98%, manufacturers need to operate at a low temperature of 96°C to ensure that the larger molecules have sufficient thermal energy to dissolve.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  
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  • Introduction to EVA hot melt adhesive
    Jun 07, 2022
    EVA hot melt adhesive is a solvent-free, water-free, 100% solid fusible polymer. It is solid at room temperature and becomes a liquid adhesive that can flow and has a certain viscosity when heated and melted to a certain degree. It is light brown translucent or white after melting.   EVA(EVA V6110S) hot melt adhesive is mainly made of the following four components: base resin, namely EVA resin, tackifying resin, wax, antioxidant, and a small amount of filler can be added in some occasions to increase the gap filling and reduce costs.   EVA hot melt adhesive has the following characteristics: (1). It has fast curing, low pollution, strong adhesion, and the adhesive layer has certain flexibility, hardness, and toughness; (2). After the adhesive liquid is applied to the adherend and cooled and solidified, the adhesive layer can be heated and melted again to become an adhesive body and then bonded to the adherend, with a certain degree of re-adhesion; (3). When using, just heat and melt the hot melt adhesive into the required liquid state and apply it to the adherend. After pressing, the bonding and curing can be completed within a few seconds, and the hardening, cooling and drying can be achieved within a few minutes.   The type of EVA determines the cohesive strength, flexibility, adhesion to the substrate and processability of the hot melt adhesive. For hot melt adhesive, the following properties of EVA should be paid attention to: molecular weight and its distribution, vinyl acetate (VA) content, crystallinity, softening point, melting point, melt index (MI) and melt viscosity, etc., because these properties directly affect the various properties of hot melt adhesive.   As the melt index of EVA increases, its strength, hardness, softening point and viscosity all decrease regularly; and the more VA content in EVA, the greater the elongation at break and the lower the hardness. In addition, when the VA content exceeds 30%, although the adhesion to polar and various non-porous non-polar substrates is improved, this EVA polymer is incompatible with wax, which is a point to be noted when designing hot melt adhesive formulas. In a formula, it is often necessary to use EVA with different MI or EVA with different VA content to obtain satisfactory comprehensive performance.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.
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  • The useage of EVA shoe material
    May 26, 2021
    Ethylene Vinyl Acetate (EVA) is a lightweight material. Compared with other shoe materials such as rubber and leather, it is lighter in texture and has excellent softness, which can better fit the shape of the foot and make the foot feel more comfortable. Very beneficial to children's foot development. Many children's shoes are made of EVA material to provide comfort and support.   EVA shoe materials have good shock-resistant properties, which can reduce the impact on the feet during walking and running. Effectively reduce foot fatigue and protect feet from injury. It also has excellent abrasion resistance and can withstand the wear and tear of daily use. Many well-known sports shoe brands use EVA to make midsoles and insoles. Its lightweight and shock-resistant properties make sneakers more suitable for sports and workouts. EVA material also has good breathability and is also very suitable for making summer sandals.   EVA material has good waterproof properties and has good adaptability to wet and beach environments. Therefore, many beach shoes are made of EVA material, which can provide comfort and anti-slip effect in wet and sandy environments.   Manufacturing EVA shoe materials usually includes the following steps: EVA particles are usually white or transparent, and colors can be added as needed; Heat it to a molten state, and then the melted EVA is injected into the mold through an injection molding machine; The injected EVA material is further pressed and molded to obtain the final shoe material shape; The pressed shoe material needs to go through a cooling process to solidify and maintain the desired shape; Then trim to remove excess material so that it achieves the final look.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.
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