Chloroprene rubber adhesive

Chloroprene rubber adhesive is the largest and most widely used variety among rubber adhesives. It can be sorted into a few groups, like resin modified, filler, grafted, and latex types. Grafted chloroprene rubber adhesive, which is made mostly of chloroprene rubber and a grafted modifier, is known as easy to their usage, strong bonds, high initial adhesion, and many uses. As early as the 1950s, the shoemaking industry began to use chloroprene rubber adhesive. As shoemaking materials and styles change, standard chloroprene rubber adhesive may not be strong enough. This can cause the upper and sole of shoes, or composite soles, to separate. This issue harms shoe quality and limits growth in the adhesive shoe business. To solve this problem, we used a variety of graftable chloroprene rubbers at home and abroad as graft bodies and used MMA to study their grafting modification.   1 Grafting mechanism     2 Experimental part   2.1 Raw materials and polymerization formula   2.2 Polymerization Procedure Add CR to the solvent. Heat the solution to 50 °C and stir until the CR is completely dissolved. Raise the temperature to 80°C, and slowly add the MMA solution that contains BPO while stirring. Maintain the temperature and continue stirring until the viscosity reaches a suitable level (about 40 minutes). Immediately add hydroquinone to stop the reaction. Keep warm for 4 to 6 hours. After the reaction is complete, cool down to 40°C; add thickening resin, vulcanizing agent, antioxidant and filler, and finally keep warm for 2 to 3 hours, cool down to room temperature, and obtain the product. A small amount of toluene can be added to adjust the viscosity. The obtained graft copolymer (CR-MMA) is a brown-yellow transparent viscous liquid. The viscosity measures between 1000 and 1500 mPa·s. Solid content ranges from 15% to 25%, and the strength registers at 34 N/cm².   2.3 Product analysis 2.3.1 Determination of adhesive viscosity The viscosity value (mPa·s) was tested in a 25℃ constant temperature water bath using a rotary viscometer (Shanghai Optical Factory, NDI-1 type). 2.3.2 Determination of adhesive solid content The film after vacuum drying and constant weight of the adhesive was wrapped with filter paper and placed in a fat extractor. It was extracted with acetone in a 65℃ constant temperature water bath for 48 hours (to remove PMMA homopolymer in copolymerization). The solid content (W%) was calculated according to the following formula: W %=W2 / W1×100% Wherein, W1 is the mass of the grafted adhesive, and W2 is the mass of the film after vacuum drying and constant weight. 2.3.3 Determination of peel strength of artificial leather/artificial leather (PVC/PVC) bonded by adhesive The soft PVC sheet was wiped with acetone or butanone to remove the oil stains on the surface. The entire process was in accordance with GB7126-86.   3 Results and discussion   3.1 Solvent selection The solvent used in chloroprene rubber adhesive is very important. It affects the solubility of chloroprene rubber, the initial viscosity of the adhesive, stability, permeability to the adherend, bonding strength, flammability and toxicity, etc. Therefore, the selection of solvents should take into account many factors. Commonly used solvents include toluene, ethyl acetate, butanone, acetone, n-hexane, cyclohexane, solvent gasoline, etc. The test confirmed that when the solvent cannot dissolve chloroprene rubber alone, two or three solvents can be mixed in appropriate proportions to have good solubility, viscosity and low toxicity.     3.2 Effect of CR type and concentration on the performance of grafted products Different types of chloroprene rubber (CR) show differences in how quickly they form crystals and how deep their colors are. These factors can change how well the grafted materials initially stick together and how they look. Tests show that using Denka A120 Chloroprene rubber and Chloroprene Rubber SN-244X to graft chloroprene rubber results in good initial adhesion and color. The amount of CR does not change peel strength much, but it does affect how well copolymerization works. When the CR concentration is too high, that is, the viscosity is high, MMA is difficult to diffuse and has a strong tendency to self-polymerize. Maintaining the appropriate CR concentration is necessary; if it's too low, the MMA volume will be too small, which slows down the grafting copolymerization. CR concentration works best between 11% and 12%.   3.3 Effect of reaction time on the performance of grafted products Generally speaking, the longer the reaction time, the higher the grafting rate and viscosity value. At the beginning, the initial and final adhesion strengths increase with the extension of reaction time and the increase of viscosity. Extended reaction times coupled with high viscosity can actually reduce both initial and final adhesion. Experiments suggest reaction times should ideally fall between 3.0 and 5.0 hours.   3.4 Effect of reaction temperature on grafting reaction When the reaction temperature is lower than 70℃, the reaction is slow, which is due to the slow decomposition of BPO. Because BPO decomposes quickly above 90℃, leading to a rapid increase in viscosity and poorer processing, we set the reaction temperature between 80°C and 90℃.   4 Conclusion Our initial tests included scaled-up experiments and pilot production runs, which successfully yielded acceptable products. They were supplied to many leather shoe factories and achieved satisfactory results. The quality met the various standards required for shoemaking. CR-MMA grafted adhesive shows better peel strength on PVC artificial leather compared to regular CR adhesive used for boots.The addition of a small quantity of isocyanate (5-10%) can serve as a temporary curing agent. The -NCO group in the isocyanate then reacts with active hydrogen in the rubber, creating an amide bond. This reaction strengthens the rubber's internal structure, improving the overall bond strength.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Chloroprene rubber (CR) is a synthetic rubber obtained by polymerization of chloroprene. It is widely used because of its excellent aging resistance, oil resistance, corrosion resistance and other properties. Polychloroprene Rubber CR2442 vulcanized rubber has good physical properties and can be used in many occasions (Such as chloroprene rubber adhesive). However, since the process of CR2442 in internal mixing, open mixing and vulcanization is not easy to master, the physical properties of the prepared vulcanized rubber are sometimes poor, which affects its production and application.   1. The influence of process parameters on the preparation of mixed rubber and vulcanized rubber 1.1 Internal mixer mixing process CR2442 has high requirements for the mixing process. When preparing CR2442 mixed rubber, the initial temperature, mixing time and rotor speed of the internal mixer have a great influence on the discharge temperature. The discharge temperature is an important parameter for measuring the mixing process. The optimal discharge temperature of CR2442 is 110℃. The order of adding various materials during the mixing process is also important. The correct way to add materials to CR2442 during the mixing process is: add CR2442 and small materials at the same time → add carbon black → add white carbon black and operating oil in sequence.   1.2 Mixing process of open mill After the mixed rubber prepared by the internal mixer is cooled, the vulcanization system is added on the open mill. The vulcanization system includes vulcanizing agent and accelerator. The correct way to add is to add accelerator first and then vulcanizing agent. When adding the vulcanization system to the mixed rubber on the open mill, it is generally required that there is accumulated rubber on the roller. With the shearing and extrusion of the open mill, the roller temperature will increase significantly. When the temperature of the rubber is too high, the rubber should be cut, pulled out and cooled, and then the rubber should be mixed after it is completely cooled.   1.3 Vulcanization process After adding the vulcanization system on the open mill, the rubber is cooled and placed for 16~24h before vulcanization. Since the CR2442 mixed rubber is easy to crystallize at low temperatures, it is generally necessary to perform indirect heating treatment in an oven. The vulcanization time of CR2442 was set to 30, 40, 50, 60, 70 and 80 minutes respectively. After many tests, it was found that the tensile strength and elongation at break of the vulcanized rubber were the largest when the vulcanization time was 60 minutes. Therefore, the optimal vulcanization time of CR2442 was determined to be 60 minutes.   1.4 Bonding operation In the process of bonding the mixed rubber and brass, the rubber is first cut into sheets with the same length and width as the mold. After the mold is preheated, the cut film is placed in the mold cavity. Since the mold is heated, placing it too slowly will cause early vulcanization of the rubber, reduce the fluidity of the rubber, make the bonding insufficient, and then reduce the bonding force. Therefore, the scorch time should be controlled to be much longer than the placement time of the film.   2. Influence of vulcanization system, reinforcement system and bonding system Vulcanization system: When CR2442 uses only zinc oxide and magnesium oxide for vulcanization, the resulting rubber's physical properties are worse compared to when zinc oxide, magnesium oxide, sulfur, and accelerator DM are used as a system. Reinforcement system: The reinforcement system of CR2442 is often based on carbon black and supplemented by white carbon black. Bonding system: Rubber as a single material can no longer meet the needs of society, and it is often necessary to bond rubber to metal to expand its scope of use. CR2442 is usually bonded to metal using a resorcinol-methylene-white carbon black-cobalt salt bonding system.   3. Conclusion When mixing, it's important to think about temperature, how long you mix, and how fast the rotor spins. Also, when you add the vulcanization system using the open mill, pay attention to the order you add things. The heat from the rollers can really change things.For vulcanization and bonding, if you make sure the scorch time is longer than it takes to place the sample, you can get better quality vulcanized rubber and better bonding with other types of materials. The CR2442 discharge temperature matters too. It's a good idea to add white carbon black as a reinforcement in CR2442. This helps control how fast vulcanization and bonding happen.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Chloroprene rubber (CR)  is one of the commonly used rubber varieties. The strength of vulcanized rubber without carbon black reinforcement can reach 28MPa, and the relative elongation is about 800%. It has the characteristics of oil resistance, flame resistance, oxidation resistance and ozone resistance. It is soluble in benzene and chloroform. It swells slightly but does not dissolve in mineral oil and vegetable oil. 1. Progress in CR Technology Abroad Monomer Production DuPont in the U.S. came up with a liquid method to make chloroprene from butadiene. This is safer than the gas method that was first used. It can produce higher yield products at a lower cost, improve safety, and reduce maintenance costs. In 1992, the company upgraded its monomer production line, moving from a single-loop control system to a computerized distributed control system.  Post-processing technology Recent progress in CR post-processing tech is apparent in the developments related to spiral extrusion dehydration and drying. Chloroprene latex and coagulant go into a screw extruder that has a specific design. The coagulated latex removes most of the water in the dehydration section of the extruder by the back pressure. The success of this process has created conditions for the industrial production of CR and asphalt and CR and short fibers, thereby increasing the operational flexibility and being able to handle CR varieties with poor freezing film-forming and tape-forming properties. In 1992, DuPont launched a series of elastomer masterbatches including CR with Kevlar (polyarylamide) short fibers as reinforcement materials, proving that this process has begun to be used in the production of blended products. Development of new varieties There are hundreds of foreign brands. Companies in the United States and Japan have developed many high-performance special CR based on a series of mature brands. In order to improve the thermal stability of CR, Bayer has developed copolymers of chloroprene (CD) with carboxylic acid amide, carboxylic acid anhydride and (or) carboxylic acid monomers. These new CR also have better spraying and brushing characteristics. Denka Corporation of Japan has also improved traditional products and launched a new generation of CR (Denka chloroprene rubber). For example, the DCR 20 series. Tosoh Corporation of Japan is also developing special shock-absorbing CR, and has produced CR latexes with high softening temperature, good normal temperature and high temperature adhesive properties, high water resistance and stability (SKYPRENE Chloroprene Rubber).     2. Progress in domestic CR technology In 1958, Changshou Chemical Plant in Sichuan, my country built a device for producing CR by acetylene. The main CR production in China does not control the conversion rate, and many places use manual operations, which is basically a workshop-style production status. Besides the earlier producers of CR glue like Chongqing Changshou Chemical Co., Ltd., Shanxi Synthetic Rubber Company, Jiangsu Lianshui Chemical General Plant, and Tianjin Donghai Adhesives Company, Shandong Laizhou Kangbaili Glue Industry Co., Ltd. developed in October 2003 a new CR glue. They carefully chose and mixed the composite solvent.    3. Suggestions for the development of domestic CR industry Strengthen technology development For domestic carbon black firms, boosting investment in science and tech, along with adopting and assimilating advanced foreign tech, is key. These actions should lower consumption and costs, and it should raise acetylene use from 57% to over 70% quickly. Strengthen the development of new varieties To maintain the Mooney viscosity in current products, we will create new types. The focus will be on making functional latex, like carboxyl and copolymer latex. Our goal is to bring high Mooney, non-sulfur regulated WHV to industrial production. Increase market share In the next few years, the market of CR in my country will be saturated, and relevant manufacturers can consider developing overseas markets. At present, the development trend of CR in the world is that the European and American markets are shrinking, while China, Eastern Europe, Russia and Southeast Asia are in the rising stage. CR can not only contend with imported goods locally, but can also progressively expand sales to North America, Eastern Europe, Russia, East Asia, and Southeast Asia.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

Chloroprene rubber (CR) is an important variety of synthetic rubber. It stands up well to light, aging, flexing, acids, bases, ozone, flames, heat, and oil. It also has good physical and electrical properties. Its comprehensive performance is unmatched by natural rubber and other synthetic rubbers. It is widely used in defense, transportation, construction, light industry and military industry. Chloroprene rubber has several uses. It's a key element in making auto parts, machinery, industrial items, and adhesives. You'll also find it in construction materials, coated fabrics, and wire and cable insulation. By itself, chloroprene rubber is used to create rubber harness clips and shock absorbers for cars and farm equipment. Initially, chloroprene rubber from Japan's DENKA and Japan's Toyo Soda was used. Later, due to the increase in raw material prices and the restrictions of the procurement cycle, a series of research and development work on the replacement of imported chloroprene rubber with domestic chloroprene rubber was carried out. Finally, the replacement goal was successfully achieved, and some process and formula problems of domestic chloroprene rubber in the use process were solved.   1. Neoprene rubber model Imported neoprene rubber model: Denka M120 Chloroprene Rubber, a product of Japan DENKA, light-colored blocks; B-10, a product of Japan Toyo Soda, light-colored blocks. Domestic neoprene rubber model: CR3221, a product of Chongqing Changshou Chemical Co., Ltd. Polychloroprene Rubber CR3221 is a chloroprene polymer with sulfur and diisopropyl xanthate disulfide as mixed regulators, with a low crystallization rate, a relative density of 1.23, beige or brown blocks, and a non-polluting type.   2. Production process performance comparison Imported neoprene handles better during production. For example, the raw rubber pieces do not stick together, even after baking, which makes them easy to measure. The process is smooth; it does not stick to the roller, so removing it is simple. The semi-finished film is stiff and holds its shape well. Domestic neoprene does not perform as well. The rubber pieces tend to stick, especially after baking. The rubber also sticks to the roller, which makes removal hard, and the semi-finished film sticks easily and loses its shape. Despite these things, domestic neoprene has some benefits. It mixes powder faster and with less effort in both internal and open mixers. Rubber from Japan is harder to mix. In the open mixer, M-120 can even fall off the roller at first. The internal mixer requires more effort and time, especially in the winter. Domestic mixed rubber still works well after being stored for a long time. Rubber from Japan, especially M-120, gets hard and loses its flexibility after two to four weeks. Tests show that production methods that work for imported neoprene do not work well for domestic neoprene. The original method needs some changes. If not, it will be hard to make it work for production, even when the physical and mechanical qualities meet the standards.   3.  Conclusion Compared with Japanese chloroprene rubber, domestic chloroprene rubber CR3221 has lower Mooney viscosity and greater viscosity, which is more favorable for mixing and powder consumption, and can significantly reduce the operation time, but the processability is poor and the operation is difficult. If the temperature is not well controlled, the operation is improper or the rubber is over-mixed, it may cause the roller to stick or even fail to unload normally. By selecting the correct process conditions and methods and adjusting the formula appropriately, it can fully meet the production needs.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Chloroprene rubber (CR), a synthetic material, is a common choice for making timing belts because of its good physical and chemical traits. Neoprene timing belts resist aging well and work best in regular transmission systems, but some situations might need different materials. 1. Aging resistance of chloroprene rubber timing belts Neoprene resists oxidation well, helping timing belts stay flexible and strong during regular use. This prevents the material from getting fragile or breaking down due to oxidation, making it good for machines exposed to air for extended periods, as it reduces the possibility of cracks or surface hardening. Heat resistance: The operating temperature range is generally between -20°C and 100°C, and it can operate for a long time in a medium-high temperature environment; under high temperature conditions, although its performance will decrease slightly, the aging process can be delayed by adding heat-resistant agents. Anti-ultraviolet performance: Neoprene has moderate anti-ultraviolet ability, but the surface may oxidize under long-term exposure to strong light, resulting in color changes and the formation of tiny cracks. Moisture resistance: Neoprene has good resistance to moisture and is suitable for high humidity environments. It is not easy to deteriorate due to moisture intrusion. Chemical corrosion resistance(Chloroprene Rubber SN-236T): It has good corrosion resistance to grease, weak acid, alkali and some chemical solvents, which slows down the aging rate, but is not suitable for contact with strong oxidizing chemicals.   2. Applicable scenarios of chloroprene rubber timing belts Industrial transmission equipment(Chloroprene Rubber SN-244X): Applicable to power transmission of conventional mechanical equipment, such as textile machinery, packaging equipment and general processing equipment. Medium temperature environment: It performs well in medium and high temperature (below 100°C) application scenarios, such as industrial drying equipment or HVAC systems. Indoor environment: Equipment with low requirements for UV resistance, such as indoor automation equipment or low maintenance systems. Medium humidity and chemical environment: It can be applied to equipment that contacts oils and weak acid and alkali environments, such as food processing machinery and light chemical equipment.   3. Limitations of aging resistance of chloroprene rubber timing belt Prolonged exposure to temperatures above 100°C can speed up the aging process, leading to reduced flexibility or hardening of the timing belt. When working in such conditions, fluororubber or silicone rubber belts are the preferred choice. Extended exposure to strong sunlight can cause surface oxidation and cracking, which reduces the lifespan of the belt. Polyurethane belts or those with anti-UV coatings are advisable for outdoor setups. Strong acids, bases, or concentrated chemical solvents can cause corrosion if the material isn't resistant enough.   4. Methods to extend the aging resistance of chloroprene rubber timing belts Reasonable storage: Store in a dry, ventilated, light-proof environment to avoid ultraviolet radiation and high temperature. Regular inspection: Regularly check whether there are cracks or hardening on the surface of the timing belt during use, and remove oil and chemical residues in time. Adding antioxidants: By adding antioxidants or anti-ultraviolet ingredients during the manufacturing process, the aging resistance of the timing belt can be significantly improved. Optimize working conditions: Avoid running the synchronous belt under excessive tension or extreme temperature to reduce the risk of aging.   Chloroprene rubber synchronous belts resist oxidation, heat, and moisture well, so they age slowly and work for many standard jobs. Still, they might not work as well when it's very hot, there's a lot of ultraviolet light, or things are very corrosive. You can make these belts last longer by storing and using them properly and keeping up with regular maintenance. Because of this, they're a solid, affordable choice.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

CR modified materials are really popular these days.  A company called Shanghai Shuangpu Rubber Anti-Corrosion Lining Co., Ltd. has rolled out a bunch of different rubber linings, like CR, CR/NR, and NBR/CR. These products are proving to be quite useful across various sectors, including chemicals, electricity, steel, mining, and water treatment. You can see more about this in Figure 1.   Interestingly, Shanghai Shuangpu Rubber Anti-Corrosion Lining Co., Ltd. has done some side-by-side tests and discovered that certain fluoroprene rubbers made locally are performing on par with similar CR products that come from Japan and Germany. This is great news for the local industry, as it shows that we’re capable of producing high-quality materials that can stand shoulder to shoulder with the best from around the world. So, whether it’s keeping things from rusting or just making tough parts for machines, these rubber linings are definitely pulling their weight in various industries.   However, there are still few varieties of domestically produced fluoroprene rubbers, and there is no low-hardness fluoroprene rubber material. The existing main varieties, such as Chloroprene Rubber CR121, Chloroprene Rubber CR232, etc., are made of fluoroprene lining rubber sheets that are relatively hard, and the pre-vulcanized rubber sheets produced are very hard, making the pasting construction difficult. Further tests show that adding a large amount of softener to the formula can reduce the hardness, but when it reaches a certain amount, it will significantly affect the bonding strength. The production test also shows that the bonding strength of the cold-adhesive adhesive produced by domestic Chloroprene Rubber CR244 is completely up to the level of foreign Denka A90 Chloroprene Rubber and Bayprene 213. However, after being applied to the steel plate and rubber plate, the bonding retention time of the adhesive coating is significantly lower than that of the adhesive made of Denka A90 Chloroprene Rubber and Bayprene 213, and it is more obviously affected by the ambient temperature and humidity, which increases the difficulty of rubber lining construction of large equipment and increases the quality risk. It can be seen that there is still a lot of room for research and improvement in the material variety and application characteristics of domestic fluoroprene.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com