As a rubber processing aid, it can enhance the diffusion of fillers, increase the extrusion rate, increase the mold flow, facilitate demolding, and improve the surface brightness and smoothness of the product after demolding.
Rubber: to protect rubber from the erosion of electrostatic ozone and improve the dispersibility of carbon black in rubber, it is recommended to add 2-5phr;
The use of PE wax in rubber is a chemical material, in which the color of polywax is small white beads/sheets, which are formed by polymerizing rubber processing agents, which have high melting point, high hardness, high gloss, The color is white and so on.
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 microcrystalline in the surface layer of the coating to play a wax-like substance similar in appearance to paraffin but with more different properties than paraffin.
The main functions of PE wax in the solvent-based coating film are: extinction, scratch resistance, abrasion resistance, polishing resistance, marking resistance, anti-blocking, anti-precipitation, and thixotropy. Good lubricity and machinability. Metallic pigment.
1. Lubrication and dispersion
Generally, some fillers are added for the mixing of rubber or silica gel, and some are added with carbon black, calcium carbonate, talc, etc., and some white carbon black is added for those with high transparency requirements. Adding polyethylene wax can play a certain role in lubricating and dispersing.
2. Anti-stick demoulding
General rubber is more sticky, easy to stick mold! Polyethylene wax can play a certain role in external lubrication.
3. Anti-ozone, physical antioxidant of rubber products, migrate to rubber products to form a protective film to play an anti-ozone effect.
4. Appropriate addition can reduce the Mooney viscosity of the mixed rubber and play a plasticizing role, but it should be noted that excessive amounts will affect the mechanical properties of the rubber compound.
5. A certain fluidity of product extrusion, calendering and vulcanization molding.
6. Improve the uniformity of the mixed rubber: the self-lubrication of the internal and external rubber materials and the dispersibility of inorganic additions can improve the mixing uniformity of the mixed rubber.
However, most manufacturers will choose polyethylene wax for the following reasons:
1. The melting point is relatively high
Some rubbers are mixed at a temperature of 70-120°C, while polyethylene wax has a high melting point, is not easy to melt, and has no effect. (Generally, the softening point of polyethylene wax is about 70-100℃)
2, easy to precipitate
Rubber is a polymer material, and polyethylene wax has a smaller molecule, and it is easy to precipitate if it is added too much. (2-4phr is suitable)
3. Narrow use range
Mainly limited by the melting point.
4. Affect the transparency of products
The advantages of PE wax on rubber
1. Anti-ozone aging: polyethylene wax will precipitate out of the rubber surface to form a protective film;
2. Plasticization to improve processing performance: The molecular weight of polyethylene wax is much lower than that of rubber, and its molecular chain can easily enter the rubber molecular chain after adding, making the rubber molecular chain easier to slide;
3. Lubrication (internal lubrication + external lubrication), improve extrusion performance and reduce shrinkage: the same as 2;
4. Make the rubber compound easier to mix evenly: polyethylene wax enters between the rubber molecular chains, expands the distance between the rubber molecular chains, and at the same time carries low-molecular compounding agents such as rubber molecular chains, so that other compounding agents are easier to disperse .
The protective wax is divided according to the purpose, PE wax, paraffin wax and microcrystalline wax can be used as protective wax.
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