How to improve high temperature silicone rubber processing fluidity and mold release

Processing rubber additives is a kind of chemical crystal that can improve the process performance of rubber material. It has energy savings, improve product quality and productivity without affecting the physical and mechanical properties of the rubber material characteristics. Although the processing rubber additives on the world, only 10%, but its varieties of complex, multi-functional is not to be ignored. Especially with the adoption of high-speed processing equipment in China's rubber industry and efficient processing technology requirements for additives, and vigorously develop the processing additives has been a top priority. Processing aids mainly include dispersants, homogenizers, release agents, plasticizers, tackifiers, coupling agents, reinforcing resins, spraying agents and anti-focusing agents. (1) Dispersant. Dispersants mainly to improve the dispersion of carbon black and other powders in the adhesive, mostly polymerized polymer fatty acid ester products or mixtures with metal soaps. Rubber with the dispersant, can accelerate the powder dispersion, prevent sticky rollers, reduce scorching and shorten the twisting time. This polymer fatty acid esters in addition to help the powder dispersion function, but also has a plasticizing effect, is conducive to improving the fluidity of the rubber. At present, the main foreign StrMktolwB212, Dlsper2atorrL and aAHux high-efficiency dispersant varieties. Domestic dispersants have also carried out in-depth research, now on the market the main grades are AT-C, AT-B, BF-287, Gum Yisu T-78 and FS-200 and so on. (2) Homogenizer. The main function of the homogenizer is to solve the different polarity and different viscosity polymer **** mixing, it is composed of different polarity of the low molecular resin mixture. In the premise of not affecting the mechanical properties of the rubber and vulcanization properties, in addition to improving the polymer *** mixing and stabilizing the phase structure, but also has a plasticizer, viscosity and lubrication functions, can improve *** mixing rubber processing, reduce energy consumption. The same elbow, can also effectively improve the airtightness of the tire liner rubber, is a very effective class of processing aids. The main foreign brands are Germany S. S company's 40MS, 60NS, HP55, THl0A and Germany DOG company's HS01B and other products. Although there are similar domestic products, but can not completely replace imports, and has not yet formed a large-scale production, is currently mainly dependent on imports. According to preliminary statistics, in 2006, only the tire industry on the demand for uniform agent reached about 4,000 tons, in accordance with no higher than foreign products in the domestic sales price, at least should be 1.4 billion yuan of market prospects. (3) mold release agent. Release agent is mainly used in the field of polymer molding process a class of processing aids. Its main function is to make the mold release operation is a breeze, to prevent forced removal of the product damage. Mold release agents are generally divided into two types: external and internal. The traditional release agent is generally external type, that is, coated on the surface of the mold cavity, customarily also known as isolation agent, the products are mainly talcum powder, mica powder, soap, paraffin, PTFE and silicone oil, etc., they have a certain degree of demolding effect, but with the easy to leave the mold scale and traces of the mold has a corrosive effect on the mold, the price of the more expensive and other shortcomings. Internal mold release agent is generally in the form of additives in the refining of rubber when added, the use of very convenient, and long-term maintenance of the mold is beneficial. In addition, the mold release agent also helps the flow of rubber, reduce the heat generated by the molecular friction, is a real multi-functional additives, therefore, in foreign countries called "lubricant". China has not yet been applied to a variety of rubber products characteristics, excellent performance of the mold release agent. (4) Plasticizer. Plasticizers are used to improve the processing properties of polymers, to improve their softness or tensile properties of processing aids. According to its mechanism of action can be divided into two categories of physical and chemical plasticizers. It is customary to call physical plasticizers as softeners and chemical plasticizers as plasticizers. Chemical plasticizers are added in the plasticizing of raw rubber, through chemical action, not only has the effect of improving the plasticizing, shorten the plasticizing time, save energy, and has the advantages of less dosage, strong plasticizing power, no effect on the performance of the products, and so on. For many years, China has been using PCP products with good effect. However, due to the toxicity of PCP, foreign countries have adopted non-toxic, non-polluting, non-spray frost and good plasticizing effect of new varieties to replace it. China's Beijing Rubber Co., Ltd., Shandong Yanggu Huatai Chemical Company and other companies to develop the chemical plasticizer is also non-toxic, efficient chemical plasticizer, there are good prospects for use. Physical plasticizer is a rubber processing process used to improve the rubber processing performance of the help, it can reduce the viscosity of the rubber mixing, increase the plasticity of the cavity material, but also to improve the dispersion of carbon black and other agents, improve the physical properties of vulcanized rubber. Unsaturated or saturated fatty acids, fatty acid esters or their zinc soap is currently the most widely used physical plasticizer. This kind of physical plasticizer mainly as an elastomer and filler network in the internal lubricant, therefore, in the mixing only small shear or at a lower temperature can make the rubber material to produce greater fluidity, in order to achieve high efficiency plasticizing effect, can reduce energy loss and avoid burning. Germany's ASOP and A60 series and China's plasticizer A, plasticizer B and plasticizer Z210 and Z300 are excellent performance of the physical plasticizer. (5) Tackifier. Tackifier is able to improve the raw rubber and unvulcanized rubber viscosity of a class of special additives, generally divided into two categories of cobalt salt and resin. Cobalt salt rubber adhesive, including cobalt naphthenate, cobalt stearate, cobalt borate and cobalt aragonate, etc., mainly used for rubber and brass-plated or zinc-plated metal bonding, is a steel wire radial tire and other rubber and metal composite products of important raw materials. Foreign companies producing drilling salts mainly include France's HONEPOUULENC Company and the U.S. Shepherd Company. Domestic Zhenjiang Jinwei Group Company production of RC series of tackifiers have been popularized, but for various reasons, the annual output remains at about 200 tons, far from meeting the domestic demand, the current product imports amounted to 60%. Tackifier resin mainly includes petroleum hydrocarbon resins, Gumarone indene tree wax, rosin tree wax, terpene resins and non-thermally reactive phenolic resins, whose main function is to improve the self-adhesive rubber and tire molding adhesion, in order to reduce the lack of adhesion due to the rubber must be manually coated with gasoline or slurry caused by the waste of the realization of the tire production linkage to improve production efficiency. The viscosity increased by non-thermal reactive alkyl phenolic resins is 2-3 times higher than that of petroleum resins, therefore, it is the most used in the tire industry. All of these tackifying resins have high initial viscosity, but after long-term storage or in the warm, hot and humid conditions of the rubber tackifying performance will soon decline, therefore, the development of heat-resistant, moisture-resistant, high viscosity and long-lasting products is the development trend of tackifying resins. At present, such products abroad are mainly Koretaek series, Durez series, SP series, Dyphenl, PA-50, R series and so on. Such products have caused domestic production and research units to pay attention to, at present, Taiyuan Organic Chemical Plant, Qingdao Auxiliary Plant and Shanghai Rubber Auxiliary Plant has some similar products. (6) coupling agent. Coupling agent can effectively inorganic groups and organic polymers closely linked to improve the processing properties and physical and mechanical properties of rubber. There are many kinds of coupling agent, at present, the most widely used are silane coupling agent and titanate coupling agent. Nanjing Shuguang Chemical Factory R & D and production of the main grades are KH845-4 and SG-S1996, has formed 6000 tons / year capacity, its production process, production scale, product quality up to the international advanced level, with a strong market competitiveness, in the world formed the German Degussa, China Nanjing Shuguang, the U.S. Compton organosilane coupling agent tripod situation. (7) Reinforcement resin. Reinforcement resin, also known as reinforcing hardening resin, used in the need for high hardness, high reinforcement and due to the increase of carbon black too much and more difficult to produce the rubber. At present, the application of more is phenolic resin, this resin and carbon black and elastomer not only exists between the strong pole interaction, so that the rubber products to obtain high mechanical properties, but also has the viscosity, plasticizing and softening function, is now widely used in the international community. The main foreign Durez series, SP series, Duphene series, PA-5 series, Koreforte series and R series of products. In recent years, China's Shanxi Chemical Industry Research Institute developed DQ205 and DQ206 reinforcing resin in the nap tire rubber has also been applied, the domestic market has basically formed. Beijing Rubber Industry Research and Design Institute launched the PFM series of reinforcing resin can not only improve the mechanical properties of the rubber, but also has the characteristics of low Mooney viscosity and burnt time is long, reaching the level of similar products abroad, has been put into production. (8) Spraying agent. Spraying agent according to its use in the outer tire on the different parts, usually within and outside the points. External spraying agent is divided into solvent-based and water-based. Due to the solvent-type external spraying agent on the human body has harmful, so now basically do not use. The water-based external spraying agent gives the tire a good ability to identify the color rubber, flame retardant, non-polluting, can increase the cleaning cycle of the mold and reduce the advantages of equipment investment, and therefore widely used. Internal spraying agent is used to spray the inner surface of the tire after molding but not vulcanized, its main role is to make the outer tire easy to demold, easy to pull out the curing capsule from the inner cavity of the outer tire and improve the quality of the tire and the appearance of the quality of the tire, to improve the product qualification rate. Foreign countries have used the third generation of products, but domestic attention is not enough, has not developed similar products. (9) Anti-coking agent. Anti-coking agent is in the storage and processing of early vulcanization, and can significantly improve the storage stability of vulcanized rubber and calendering at high temperatures under the safety of an additive. Anti-coking agents traditionally used in the rubber industry are salicylic acid, phthalic acid perylene, etc.. Their anti-coking efficiency is low, and other physical properties of the rubber material has an impact. Anti-coking agent CTP is a more ideal varieties of steel cord rubber in the addition of CTP can slow down the sulfur and rubber in the double bond reaction rate, so that there is enough sulfur and steel reaction to generate Cu-S-R bond, so that rubber and steel wire firmly bonded together. Foreign products are mainly Santogard, TPA and so on. Domestic has developed a CTP, MTP and anti-focusing agent and other varieties, these products have excellent anti-focusing effect, no pollution, no discoloration, without affecting the rate of vulcanization under the conditions of the rubber fluidity has been greatly improved. (10) other types of additives. Rubber industry, in addition to the function of the additives and technical content of the requirements, but also on the environment and health put forward higher requirements, which is a feature of modern rubber processing technology, but also the modern level of additives and the need to win the market. New additives such as granulation, surface treatment and pre-dispersion show the new level of modern additives. Will be easy to adhere to the liquid-type additives and easy to fly the powder additives with extrusion granulation technology, melt drop molding technology or compound granulation technology into granular products, in order to eliminate the toxic substances of dust flying or liquid pollution caused by the environment and health problems. Advanced countries of rubber chemicals granulation technology has developed to a fairly high level. In the past 10 years, China's granulation technology has also made great progress. Lanzhou Chemical Machinery Research Institute of extrusion granulator, Nanjing Powder Engineering Institute of molten drop molding technology and the Beijing Rubber Industry Research and Design Institute of polymer as the carrier of the composite granulation technology have been successful, so that a large number of domestic additives products to achieve granularity. Rubber nanocomposites are also one of the research hotspots due to the nano effect brought by nanoparticles and the strong interfacial interaction between nanoparticles and matrix. At present, there are rubber-clay nanocomposites, rubber-silica nanocomposites, hydrogenated nitrile butadiene rubber-acrylic acid metal salt nanocomposites and so on under research, which show attractive application prospects due to their special structure and excellent performance. Pre-dispersed rubber additives are rubber additives masterbatch with polymer as carrier. Using pre-dispersed additives masterbatch to replace ordinary powder additives can reduce dust, improve dispersion effect and processing performance, and improve product quality. Germany Rheinland company first developed successful pre-dispersion technology, has formed a global production capacity of 70,000 tons / year, specifications of thousands of varieties, doubly favored by the rubber processing enterprises