What is the most suitable temperature for neoprene grafting process?

overview chloroprene rubber (originally called duprene) is the first synthetic rubber compound produced in large quantities. Neoprene rubber (commonly known as all-purpose rubber) is a traditional bulk adhesive in Chinese mainland. This adhesive has a wide range of applications, and has the characteristics of high initial adhesion and high bonding strength. It is mainly used in the decoration of homes and public facilities, wood industry, shoe industry and other industries. Neoprene is the first synthetic rubber invented by DuPont, which can be used in various environments, such as thermal diving suits, notebook computers, electrical insulation materials and automobiles, fans, conveyor belts and so on. Brief history chloroprene rubber was invented by DuPont scientist Elmer K. A lecture was given by Fr. at DuPont laboratory in Burlington. Julius Arthur Nieuwland teaches chemistry at Notre Dame University. Nieuwland's research focused on acetylene chemistry. During his work, he produced divinyl acetylene, which solidified into an elastic compound similar to rubber, when passing through jelly sulfur dichloride. After DuPont purchased the patent rights from the university, Wallace Carothers DuPont accepted Nieuwland's discovery of business development and cooperated with Nieuwland. Dupont focuses on the field of monovinyl acetylene, and studies reaction substances and hydrogen chloride gas to produce chloroprene. In 1937, the first synthetic rubber Neoprene was invented by DuPont. In 1957, Bayer Company introduced rapid crystallization chloroprene rubber. Types of chloroprene rubber are divided into anionic and nonionic types. There are many types of anionic chloroprene rubber for various adhesive purposes. The nonionic type is a * * polymer of chloroprene and methacrylic acid, which has good stability and carboxyl functional groups. Components such as antioxidant (antioxidant 264 or 2246, etc.), metal oxide (ZnO), resin (terpene phenolic resin, benzofuran-indene resin, terpene resin, rosin ester, etc.), filler, etc. can also be added according to requirements. Nature monomer: colorless, volatile, narcotic and toxic liquid; Slightly soluble in water, soluble in many organic solvents; The melting point is-13 2℃, the boiling point is 59.4℃, and the relative density is .958 3 at 2℃. It has the general characteristics of * * * yoke double bond, which is very active and prone to addition and polymerization. Its polymerization rate is 1 times higher than that of butadiene. Neoprene rubber has a regular structure and chlorine atoms with high polarity, so it has high crystallinity, which makes it have good adhesion and great cohesive strength at room temperature. The characteristics of neoprene adhesive are as follows: 1. The initial adhesion is large, and most neoprene adhesives are room temperature curing contact type. After being coated on the surface, they can crystallize instantly after being properly exposed and closed, and have great initial adhesion. 2. The bonding strength is high, and the strength is established quickly. 3. It has good adhesion to a variety of materials, so chloroprene rubber adhesive is also known as "all-purpose adhesive". 4. Good durability, excellent flame resistance, light resistance, ozone resistance and atmospheric aging resistance. 5. The adhesive layer is flexible, elastic and resistant to impact and vibration. 6. Good medium resistance, good oil resistance, water resistance, alkali resistance, acid resistance and solvent resistance. 7. It can be made into single component, which is convenient to use and low in price. 8. Poor heat resistance and cold resistance. 9. Solution chloroprene rubber adhesive is slightly toxic. 1. Poor storage stability, easy to delaminate, gel and precipitate. The production of chloroprene rubber is all produced by emulsion polymerization, and the production process is mostly single kettle batch polymerization. The polymerization temperature is mostly controlled at 4 ~ 6℃, and the conversion rate is about 9%. The polymerization temperature, the final conversion rate is too high or the air (oxygen) enters during the polymerization process will lead to the decline of product quality. In the production, the molecular weight is adjusted by sulfur-Qiu Lan system. The main disadvantage of sulfur-Qiu Lan system is that sulfur bond is not stable enough, which is one of the important reasons that affect storage. This property can be improved if the molecular weight is adjusted by mercaptan. Chloroprene rubber is different from general synthetic rubber. It is vulcanized with zinc oxide and magnesium oxide instead of sulfur. The application of chloroprene adhesive has high cohesive strength, heat resistance, oil resistance and aging resistance, and has good bonding effect on metals and nonmetals. Used in woodworking, furniture, shoemaking, construction, electronics, textiles, transportation, machinery and other departments. Can be made into contact adhesive. The chloroprene latex was modified by blending technology, and the adhesive made of acrylate latex and nonionic chloroprene latex was equivalent to solvent-based chloroprene adhesive in performance. Its chemical inertness makes it very suitable for industrial applications, such as gaskets, water pipes and corrosion-resistant coatings. It can be used as a base for adhesive noise isolation in power transformer facilities, and as a packing for protecting contents in external metal boxes when sliding fit is allowed. Neoprene, when in sheet form, is so soft and consistent that it is difficult to fold. Neoprene is a commonly used material, which provides excellent insulation materials. Neoprene diving suits are usually about 5 mm thick, and compared with cheaper materials such as nylon and rubber in the middle price range. However, neoprene is less expensive than fabrics suitable for inhalation. For diving and thermal insulation protection applications, the airspace in neoprene is filled with nitrogen for its insulating material value. This also makes the material quite light, and divers must make up for it by wearing weight. Thick diving suits are made at the extreme of their cold water protection, usually made of 7 mm thick neoprene. It is worth noting that, because neoprene contains airspace, the material is compressed under water pressure, and the diluent is obtained at a more remarkable depth. Such a 7 mm neoprene diving suit provides less exposure protection under 1 feet of water than on the surface. The recent advance in neoprene for diving suits is the "super buckling" combination of Spandex elastic fibers into neoprene for greater flexibility. Recently, neoprene adhesive materials include notebook computers, iPod, remote controllers, etc. The chloroprene rubber harmful to Chinese mainland production is basically triphenyl (benzene, toluene, xylene) solvent, which contains a lot of harmful organic substances. Because the solvent in chloroprene rubber is often released into the air during use, the excessive release of harmful gases seriously pollutes the environment, and at the same time, it will slowly release organic gases after decoration, which will also bring harm to people's health. At first, the solvent used in chloroprene rubber was benzene, which had excellent solubility and the properties of the adhesive were easy to control. However, benzene was quite toxic, so toluene was used as the solvent after many accidents of poisoning and death of operators. Although the toxicity of toluene is much less than that of benzene, it can still seriously poison operators and pollute the environment if improper measures are taken. In the 198s, there was a research on replacing most or all toluene with mixed solvents such as gasoline and ethyl ester. However, due to the increase in cost, unstable adhesive performance, and aggravated pungent smell, workers were reluctant to use it. In addition, the environmental protection and labor laws and regulations at that time did not specifically emphasize that toluene was not allowed to be used. Therefore, benzene-free solvent chloroprene rubber has not been popularized. In the mid-199s, there were many accidents in some shoe production bases in which workers were poisoned by "triphenyl", which led to leukemia and even death, and the voice of restricting the use of "triphenyl" glue became increasingly strong. With the increasingly stringent requirements of environmental protection, the application of solvent-based adhesives is also subject to increasingly stringent laws and regulations. Many advanced countries have stopped or restricted the use of neoprene containing triphenyl solvent, and turned to develop environmental-friendly adhesives. At present, more than 9% of the building materials in advanced countries such as the United States and Western Europe have reached the "green" standard, but Chinese mainland is still in its infancy, with less than 5%. Some European countries regulate that the indoor toxic gas content should not exceed .15mg/m3. At present, the national general administration of quality and technical supervision, inspection and quarantine of Chinese mainland is about to issue the compulsory standard of "limit of harmful substances in indoor building decoration materials", which has stipulated the limit of triphenyl content in solvent-based adhesives and will be enforced within a time limit. Therefore, it is imperative to develop, popularize and use pollution-free, healthy and environmentally friendly synthetic adhesives. On June 27th, 21, the Standardization Department of the General Administration of Quality and Technical Supervision, Inspection and Quarantine of Chinese mainland held a meeting on "Formulating the National Mandatory Standard for the Limit of Hazardous Substances in Indoor Building Decoration Materials (Adhesives)". On November 28th, 21, at the National Adhesives Standardization Technical Committee held in Kunming, the national standard "Limits of harmful substances in interior decoration materials (adhesives)" was first passed, and the limits of harmful substances in solvents were clearly stipulated, among which benzene was prohibited from being used alone in solvent-based chloroprene rubber, and its content should not be more than .5g/Kg. This standard will be implemented on July 1, 22. Chloroprene produced in Chinese mainland is basically triphenyl (benzene, toluene, xylene) solvent type, which contains a lot of harmful organic substances. According to the statistical data provided in the Proposal of the Tenth Five-Year Plan put forward by China Adhesives Industry Association to Chinese mainland State Petrochemical Bureau, the output of chloroprene rubber and graft rubber in Chinese mainland was 218,6 metric tons in 1998, 25, metric tons in 1999, and it has dropped to 178, metric tons in 2. Because the neoprene technology is simple, the technical level is low, the manufacturers are extremely scattered, and the management level is not high, most of the products produced by township enterprises and private enterprises in Chinese mainland do not meet the requirements of environmental protection, and it will be difficult to develop sustainably in the future. With the increasingly fierce market competition, stricter environmental protection requirements, rising people's awareness of environmental protection and the upcoming "limit of harmful substances in indoor building decoration materials (adhesives)" and other factors, some uncompetitive small enterprises are expected to be eliminated. According to statistics, there were nearly 1 adhesive manufacturers in Chinese mainland in 1998 and more than 12 adhesive manufacturers stopped production in 1999. On the other hand, foreign-funded enterprises have sprung up one after another, and internationally renowned enterprises have rushed to the Chinese mainland adhesive market. According to relevant data, six of the top 1 adhesive manufacturers in the world have invested in Chinese mainland to establish joint ventures or wholly-owned enterprises, which is expected to have a direct impact and impact on the adhesive-related industries in Chinese mainland in the future. When the use history of triphenyl solvent-based neoprene is coming to an end and no triphenyl solvent-based decorative adhesive will be introduced. We should develop green products, increase investment and development, realize the upgrading of adhesive products, and vigorously develop environmental-friendly synthetic adhesives. Focus on the development of research, development, promotion and use of solvent-free neoprene, and accelerate the elimination of solvent-based neoprene containing triphenyl.