Xin Han Rubber Technology (Shenzhen) Co.,Ltd

EVA, or ethylene-vinyl acetate copolymer, is currently a common material used in shoe soles and uppers in shoe processing companies. EVA foam sole has good moisture absorption, heat resistance, abrasion resistance, weather resistance, and oil resistance, but it is easy to slip when walking in wet ground, and the sole is hard under low temperature conditions. This is caused by its own material defects. With the continuous development and advancement of rubber and plastic combined technology, the use of natural rubber in EVA soles can significantly improve the easy slippage and hardening of EVA soles at low temperatures, and can also improve the puncture resistance of rubber soles. 1. Control the amount of natural rubber Reasonable use of natural rubber in EVA soles can significantly improve the overall performance of the soles, but in actual production, the amount of natural rubber is not the better. It is understood that the foaming efficiency of EVA foam soles is closely related to the amount of natural rubber. The foaming rate continues to decrease with the increase of the amount of natural rubber. When the amount of natural rubber increases, the melt viscosity of the blended material 2LLYY0313-SJ will increase, which in turn causes The problem of difficulty in degassing and uneven foaming of foamed materials, the shrinkage of the finished EVA foam bottom is significantly increased. Under normal circumstances, in the production of EVA-natural rubber foamed soles, the amount of natural rubber should not exceed 20 parts to ensure uniform foaming of EVA foamed soles and reduce the shrinkage of the finished product. 2. EVA-natural rubber foam sole compounding agent types Using a small amount of natural rubber in the EVA foam bottom can significantly improve the elasticity and elongation of the foam bottom, and the comfort of the foam bottom is significantly improved. When using EVA-natural rubber blending materials to prepare foam bottoms, when rubber products manufacturers choose peroxides such as DCP for vulcanization, the physical and mechanical properties of the blending materials are better; choosing the foaming agent AC foam can better coordinate the vulcanization speed and the hair The relationship between the foam speed, thereby further improving the foaming efficiency and foaming uniformity of the foamed rubber sole. The combination of rubber and plastic materials has better performance and lower cost, and is currently widely used. The use of a small amount of natural rubber in the EVA foam sole can significantly improve the overall performance of the sole. Butadiene rubber, styrene butadiene rubber, etc. can also be used in the foam sole formulation with EVA as the main material. In actual production, rubber product manufacturers not only need to control the amount of natural rubber and compounding agents in the EVA foam bottom formula, but also need to reasonably control the vulcanization process and foaming process of the sole according to the processing properties of the rubber and EVA materials. With regard to the production and processing of EVA-natural rubber foamed soles, the editor has the opportunity to continue discussing with you.

As a rubber processing aid, it can enhance the diffusion of the filler, increase the extrusion molding rate, increase the mold flow rate, facilitate demolding, and improve the surface brightness and smoothness of the product after the film is released. Rubber: protect the rubber from the erosion of electrostatic ozone, improve the dispersibility of carbon black in the rubber, the recommended amount of 2-5phr; The use of PE wax in rubber is a kind of chemical material. Among them, the color of polywax is small white beads/flakes. It is formed by polymerized rubber processing agent. It has high melting point, high hardness, high gloss, The color is white and other characteristics. The use of PE wax in rubber is a low molecular weight homopolymer or copolymer widely used in coatings. The so-called wax means that the polymer finally floats in the form of microcrystals on the surface of the paint to act as a waxy substance that looks like paraffin wax but has more different properties than paraffin wax. The main functions of PE wax in rubber in solvent-based coatings are: matting, scratch resistance, abrasion resistance, polishing resistance, imprint resistance, anti-blocking, anti-precipitation, and thixotropy. Good lubricity and processability. Metallic pigment properties. 1. Lubrication and dispersion Generally, rubber or silica gel will be mixed with some filling, some with carbon black, calcium carbonate, talc, etc., and some white carbon black will be added for those with high transparency requirements. Adding polyethylene wax can play a role in lubricating and dispersing. 2. Anti-sticking and demoulding Normal rubbers are relatively sticky and easy to stick to molds! Polyethylene wax can play a certain role in external lubrication. 3. Anti-ozone, a physical anti-aging agent for rubber products, which migrates to rubber products to form a protective film to play the role of anti-ozone. 4. Appropriate addition can reduce the Mooney viscosity of the rubber compound and play a plasticizing effect, but it should be noted that the excessive amount will affect the mechanical properties of the rubber compound. 5. Certain product extrusion, calendering, vulcanization molding fluidity. 6. Improve the uniformity of the rubber compound: the internal and external rubber materials are self-lubricating and have a certain degree of dispersibility for inorganic additions, which improves the uniformity of the rubber compound. However, general manufacturers will not choose polyethylene wax for the following reasons: 1. The melting point is relatively high The mixing temperature of some rubbers is 70-120℃, and the polyethylene wax has a high melting point, which is not easy to melt and does not play a role. (Generally, the softening point of polyethylene wax is about 70-100℃) 2. Easy to separate out Rubber is a high-molecular material, while polyethylene wax has a smaller molecule, and it is easy to precipitate if it is added, but generally it cannot achieve the effect if it is added. (2-4phr is appropriate) 3. Narrow range of use It is mainly limited by the melting point. 4. Affect product transparency 1. Anti-ozone aging: Polyethylene wax will precipitate out of the rubber surface to form a protective film; 2. Plasticizing and improving processing performance: The molecular weight of polyethylene wax is much lower than that of rubber, and its molecular chain is easy to enter the rubber molecular chain after being added, making the rubber molecular chain easier to slide; 3. Lubrication (internal lubrication + external lubrication) to improve extrusion performance and reduce shrinkage: the same as 2; 4. Make the rubber compound easier to mix evenly: the polyethylene wax enters between the rubber molecular chains to expand the distance between the rubber molecular chains, and at the same time, the low-molecular compounding agent is carried in the rubber molecular chain, so that other compounding agents are easier to disperse . Protective waxes are classified by purpose. PE wax, paraffin wax and microcrystalline wax can all be used as protective waxes. PE wax is polyethylene wax (PE-WAX), a kind of ultra-low molecular weight polyethylene. Polyethylene waxes are generally divided into oligomer waxes, cracked waxes, polymerized waxes and blended waxes. The domestically produced oligomer waxes are generally oligomer waxes. Other cracked waxes, polymerized waxes and blended waxes are mainly produced abroad. Polymerized waxes The theoretical analysis of the performance of the pyrolysis wax is better than that of the pyrolysis wax, and the specific use depends on the compatibility of the product. Generally, it is mainly used to improve the fluidity of polyolefin plastics, improve the dispersibility of fillers, additives, etc. It is also used as an internal lubricant for rubber and plastic materials.

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Xinhan (Taiwan) International Trade Co., Ltd. was founded in 2004
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Application skills of natural rubber in EVA foam bottom

What is the difference between rubber foam and EVA foam

Application of PE (polyethylene) wax in rubber

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