Polychloroprene Rubber CR244

In the research and development and production of high-performance industrial adhesives, chloroprene rubber has consistently held a core position due to its excellent adhesion, aging resistance, and flame retardancy. However, with the increasing demand for synthetic materials (such as PVC, PU, and EVA) in modern industry, traditional adhesives face challenges such as poor wettability and mismatched polarity. Among the many types of chloroprene rubber, Polychloroprene Rubber CR244 and Adhesive Type CR248 Chloroprene Rubber are two of the most representative products. Although they share many similarities in their basic physical properties, the differences in the critical dimension of "grafting performance" determine their ultimate performance in different industrial scenarios.   1. CR244: The Cornerstone of Rapid Crystallization and High Cohesive Strength CR244 type chloroprene rubber is polymerized using diisopropyl xanthate disulfide or dodecyl mercaptan as a regulator, possessing extremely significant physical characteristics.     ♣ Physical Characteristics and Performance Advantages CR244's most prominent technical feature is its rapid crystallization. This characteristic allows the adhesive to quickly establish initial strength after application, greatly shortening the waiting time for industrial assembly. Its regular molecular structure gives the adhesive layer extremely high cohesive strength. At room temperature, the adhesive strength exhibited by CR244 is sufficient to meet the needs of most porous materials. Its appearance is off-white or beige flakes, with a stable density of around 1.23. In terms of technical indicators, CR244 offers a very finely divided viscosity range. From the ultra-low viscosity CR2440 (13-24 mPa.s, 5% toluene solution) to the high-viscosity CR244B (above 140 mPa.s), this wide viscosity coverage allows adhesive manufacturers to precisely adjust the formulation solid content according to the needs of brushing, spraying, or scraping processes. ♣ Applications in Traditional Fields Due to its peel strength typically maintained above 90 N/cm, CR244 is widely used in the self-adhesion and mutual adhesion of traditional materials such as rubber, leather, fibers, wood, and cement products. It is comparable in performance to top-tier international models, such as Denka's A series (such as Denka Chloroprene A-100) and DuPont's AD series (such as Neoprene AD-20), and is the preferred base material for producing high-quality general-purpose neoprene adhesives.   2. CR248: A Breakthrough in Polarity Achieved Through Graft Modification If CR244 represents a general-purpose base material, then CR248 is an advanced version designed to address the challenges of bonding "difficult-to-bond materials." The fundamental difference between it and CR244 lies in the plasticity and grafting properties of its molecular chain.     ♣ Core Technology: Grafting and Copolymerization While CR248 retains the basic performance advantages of CR244, it has active sites reserved during the molecular design stage. This allows CR248 to undergo monomer grafting copolymerization with active monomers such as methyl methacrylate (MMA) and acrylic acid (BA) through chemical means. The significance of this graft modification is that by introducing polar monomer side chains onto the non-polar main chain of neoprene rubber, the surface energy and polarity of the adhesive are significantly improved. This not only improves the wettability of the adhesive on polar substrates but also enhances the bonding force at the interface through chemical bonding. ♣ Professional Performance for Synthetic Materials In modern footwear, automotive interiors, and luggage industries, synthetic materials such as PVC (polyvinyl chloride), PU (polyurethane), and EVA (ethylene-vinyl acetate copolymer) are widely used. Due to the high surface polarity or the presence of plasticizers in these materials, traditional CR244 adhesives often experience delamination. CR248 is optimized precisely for this purpose. The modified CR248 adhesive can establish a stable bridging relationship with these synthetic materials. Although its nominal peel strength (approximately 70 N/cm) is slightly lower than that of CR244, its actual bonding stability and plasticizer resistance on specific polar materials far exceed the latter.   3. In-depth Comparison of Technical Parameters of CR244 and CR248 Differences in viscosity control: CR244 tends to exhibit its viscosity gradient at lower concentrations (5% toluene solution), which is more conducive to producing highly permeable primers. CR248's technical specifications are typically based on a 15% toluene solution, and it is divided into Type I (1000-3000 mPa.s) and Type II (3001-6000 mPa.s). This means that under the same viscosity requirements, CR248 can support formulations with higher solid content, thereby reducing the environmental impact of solvent evaporation and increasing the dry film thickness per application.   Volatile content and purity: Both products exhibit excellent purity control, with volatile content strictly controlled to below 1.5% (CR248 is further optimized to 1.2%). This ensures that the adhesive does not produce excessive bubbles during the drying process, guaranteeing the density and aging resistance of the adhesive layer.   Storage stability: Both products perform similarly in terms of storage requirements. They can be stored for one year at temperatures below 20°C, while in summer environments at 30°C, it is recommended to use them within six months. For manufacturers, strict temperature control is crucial to maintaining the activity of chloroprene rubber and preventing premature self-polymerization.   4. How to choose the right product based on your needs? If the substrate is natural rubber, genuine leather, or wood products: CR244 is the preferred choice. It provides faster initial tack and higher ultimate cohesive strength, and the formulation cost is relatively more advantageous. For products requiring precise rheological control, its wide range of viscosity grades can be used for blending. If modern synthetic materials such as PVC, PU, ​​and EVA are involved: CR248 is the ideal choice. Especially when your adhesive needs to be modified with MMA to produce "universal grafting adhesive," the grafting active sites provided by CR248 ensure the efficient progress of the chemical reaction, resulting in finished adhesives with excellent migration resistance and cross-material bonding capabilities. Considering environmental protection and cost: CR248's high solid content characteristics help develop low-VOC adhesives that meet environmental standards. Although the unit price of the raw material may be slightly higher than CR244, its low rework rate and high-performance characteristics on difficult-to-bond materials often result in lower overall industrial costs.   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