Because it has excellent
Good film forming, adhesion, corrosion resistance, flame retardancy and insulation, and can be widely used in adhesives, marine coatings and containers.
Box paint, chemical anticorrosive paint, traffic paint, fire retardant paint, architectural paint and ink are all chlorine-based fine chemical products with great development prospects.
Chinese name
Chlorinated rubber CAS
No.
9006-03-5 Chinese alias
Chlorinated rubber anticorrosive paint;
Homopolymer of -2- methyl-1, 3- chlorobutadiene.
green
Rubber English alias
rubber
Chlorination;
Polyisoprene,
Chlorination;
green
natural
Rubber molecular formula
ordinary
Upstream raw materials: carbon tetrachloride, carbon tetrachloride, and natural rubber; downstream products: antirust paint, perchloroethylene fire retardant paint, high-performance construction machinery paint, reflective traffic paint, container paint, heavy-duty anticorrosive paint, rubber paint, chlorinated rubber enamel, various chlorinated rubber topcoats (protoplasm type), J06- 1 aluminum chlorinated rubber primer, chlorinated rubber primer, J465433. Development of J42-3 1 chlorinated rubber deck paint, J44-26 aluminum chlorinated rubber ship primer and chlorinated rubber ship primer. The research on CR in the world first started at 1895, and Peachey obtained the industrial production patent for the first time at1915 and at 1965438+.
Alkali industry company (now a part of ICI company) has realized industrial production.
In 1930s and 1940s, the research and production of chloroprene rubber developed rapidly. In addition to NRCR, the technology of producing chloroprene rubber from polyisoprene rubber has also appeared, but the former is the main one.
By the early 1990s, it was said that the annual output of CNR in the world was about 40kt, and by 2000 it was about 70kt.
The countries that produce chlorinated rubber in the world are Britain, America, Germany and Italy.
At present, the annual output of chlorinated rubber in the world is 40,000 t (data is t( 1995)).
The largest output is ICI Company in the UK, which is 15000t/a, accounting for 30% of the world total output; Followed by American Hercules Company, German Bayer Company, German Xudian Company and Yangshan Guoce Pulp Company.
According to the provisions of the Montreal Protocol, developed countries have closed the equipment for producing chlorinated rubber with carbon tetrachloride at the end of 1995, and gradually adopted water-phase method or other new technologies.
Xuhua Chemical adopts the technology of aqueous suspension chlorinated rubber to build an 800t/a carbon tetrachloride-free production plant.
Sri Lanka Rubber Research Institute also produced CNRE83 with good stability and solubility.
Many companies in Qatar, Italy use it as chlorinating agent and solvent to replace the traditional carbon tetrachloride CNR.
Carbon tetrachloride solvent method is mostly used by domestic manufacturers.
This technology was developed and industrialized by Shanghai Electrochemical Factory in the early 1970s.
Subsequently, Guangzhou Chemical Plant and pesticide plant in Jiande, Zhejiang Province, Yixing Chemical Plant and Xiyuan Chemical Plant in Jiangyin, Jiangsu Province also built devices and put them into operation.
At present, there are some problems in the production technology of chlorinated rubber, such as complex technological process, low degree of automation, high energy consumption, high cost and serious pollution of three wastes. During the Eighth Five-Year Plan period, Shanghai Electrochemical Plant and Guangzhou Chemical Plant organized technicians to tackle a major technical problem that has long plagued the production of chlorinated rubber-the separation and recovery technology of carbon tetrachloride solvent, but the effect was not good.
China, Jiangsu Institute of Petrochemical Technology, Sun Tonghua, etc. It took four years from 1990 to study the viscosity grading control of chlorinated rubber and the recovery of carbon tetrachloride. Its technical characteristics are as follows: (1) The mathematical model of viscosity control is established, which makes the relative deviation of product viscosity control reach the international level; (2) The consumption quota of carbon tetrachloride is 700kg/ton. ..
This technology is in a leading position in China.
However, the consumption quota of carbon tetrachloride is still very high, which is 3 ~ 4 times of the international advanced level in the 1980s (the consumption quota of ICI Company in Britain is 180kg/t).
Although great progress has been made, and two sets of devices were built in Wuxi Anticorrosion Material Factory and Yangzhou Catalyst General Factory in Jiangsu Province on 1994, the operation effect is not ideal.
1995, the United Nations has implemented the requirements of the Montreal Protocol on the use of carbon tetrachloride, which makes it urgent to develop a substitute for carbon tetrachloride or a new process of chlorinated rubber.
In recent years, little progress has been made in the research of carbon tetrachloride substitutes in China.
Only An Wei Research Institute of Chemical Technology has developed a chlorinated rubber technology with a scale of 500t/a, which is called E and has not been industrialized.
According to relevant analysis, the annual demand of chlorinated rubber in China is above 1000t in recent years. At present, the total production capacity of chlorinated rubber in China is about 2500t/a, and the actual output is less than 1000t/a, so it is very necessary to develop this product vigorously.
The performance of water-phase chlorinated rubber of Zhejiang Fenghua Yulong Chemical Industry reached the level of chlorinated rubber of similar solvents, and the price was about 10%. It is a leading enterprise in this field in China.
Process comparison The traditional chlorinated rubber production process at home and abroad is mainly carbon tetrachloride solvent method.
The process is mature, but the environmental pollution is serious, especially the solvent carbon tetrachloride is discharged into the atmosphere, which has a destructive effect on the ozone layer.
Before 1995, most devices in the world were produced by this method.
After 1995, the developed countries shut down the equipment for producing chlorinated rubber by carbon tetrachloride solvent method on schedule, and turned to the water-phase process technology that did not damage the environment to produce the product.
However, carbon tetrachloride solvent method is still the main production method of chlorinated rubber in China.
The Montreal Protocol gives developing countries a grace period of 10, that is, to stop using carbon tetrachloride in 2005. Therefore, it is very urgent and important to research and develop a new process of water-phase chlorinated rubber without pollution.
In recent years, water-phase chlorinated rubber technology has become a hot spot in China.
After years of research and development, Anhui Research Institute of Chemical Industry has successfully developed the industrialization technology of chlorinated rubber by aqueous phase method in China, and built several sets of industrialization devices in Jiangsu, Shandong, Zhejiang and other provinces, but the maximum annual production capacity is only 500 tons.
At present, the engineering problem of this process is that if the production scale increases, the key equipment such as corrosion-resistant reaction kettle, agitator and centrifuge which are suitable for chlorination, separation and other process conditions can not be used in China, which seriously restricts the amplification process of water-phase process equipment in China.
At present, chlorinated rubber in China is mainly produced by solvent method. Due to backward production technology, unclear product viscosity classification, poor quality, few varieties, low whiteness, low chlorine content, poor thermal stability, low adhesion, high solvent consumption and serious pollution.
In recent years, relevant scientific research institutes have done a lot of research on this and made some progress.
Production principle of chlorinated rubber Chlorinated rubber is usually obtained by chlorination reaction with natural rubber, because the basic structural unit of natural rubber is isoprene, and its chemical formula is (C5H 12), and there are carbon-hydrogen bonds and two unsaturated double bonds in its molecular structure. Therefore, under the action of catalyst, the hydrogen atoms on carbon-hydrogen bonds are easily replaced by active chlorine atoms, and hydrogen chloride is released at the same time.
Its chlorination mechanism is very complicated.
The most basic reaction methods are radical substitution reaction and electrophilic addition reaction, in addition to hydrogen chloride addition reaction, elimination reaction and cyclization reaction.
The reaction can be divided into the following three stages: (c10h16) n.
+
2nCl2
→
(C 10H 14Cl2)n
+
2nHCl(C 10H 14Cl2)n
+
2nCl2
→
(C 10H 13Cl5)n
+
Ammonium chloride (C 10H 13Cl5)n
+
2nCl2
→
(C 10H 1 1Cl7)n
+
The total reaction of 2nHCl can be summarized as: (c10h16) n.
+
6nCl2
→
(C 10H 1 1Cl7)n
+
Natural rubber and sodium sulfate were ground and mixed into uniform powder by 5nHCl solid state method, and then chlorinated in pressure reactor.
The chlorinated reactants were washed with water to remove salt, and dried to obtain powdered chlorinated rubber with chlorine content of 60-62%.
Natural rubber and pressurized rubber were dispersed in sodium hypochlorite solution by liquid method to prepare 70% solution, which was cooled and 20% sodium hydroxide solution (containing 6% chlorine) was added after introducing chlorine for 4 hours to obtain suspension.
At this time, the mass fraction of solid chlorine is 54 ~ 56%.
Introducing chlorine for 2-3 hours, washing, filtering and drying to obtain chlorinated rubber with chlorine content of 62-65%.
Firstly, the natural rubber was plasticated intermittently with a two-roll mill, and its relative molecular weight was greatly reduced (from 654.38+0 million to about 60 ~ 70 thousand) through shear degradation.
The plasticized film was cut into pieces of about 40 mm and 60 mm, and put into a dissolving kettle filled with carbon tetrachloride. At the same time, about 1 (based on the amount of glue) was added as a catalyst, which was stirred and dissolved at about 70℃ to form a colloidal solution with a glue mass fraction of about 5.
Then, the corrosion-resistant enamel reactor with reflux condenser is introduced.
The chlorination temperature is 60℃ ~ 70℃ until chlorine and hydrogen are no longer produced, and the product mass fraction reaches above 63.
In the early and late stages of the reaction, a small amount of air is introduced. The former can promote the chain breaking of rubber molecules and prevent cross-linking, while the latter can disperse the residual hydrogen chloride in the solution. The chlorination reaction time is about 12h.
After chlorination, chlorinated rubber solution and steam are sprayed into a tower filled with hot water, and the temperature is controlled at about 90℃. The carbon tetrachloride in the tower is recovered by the condenser, and the continuously discharged suspended matter is discharged into a water washing tank through a three-phase separator, washed until the pH value is 5.6, then dehydrated by a centrifuge, and the chlorinated rubber wet material with a water content of about 70 is separated, and the finished product is obtained by air flow or boiling drying.
Among the above three methods, the solid-phase method can't solve the heat dissipation problem, which leads to the poor thermal stability and dark color of the product, so it is limited to the kettle below 500L, which has little industrial significance, and the liquid-phase method has a long reverse process flow, which is a heterogeneous system reaction, with uneven internal and external chlorine and unstable product quality, and is rarely used in industry.
There are no reports of large-scale liquid production plants abroad, only Jiangsu Wujin has built a 100t/a plant at 1992. Due to the mature technology, solvent method is the main method to produce chlorinated rubber at home and abroad.
However, this method has obvious problems such as complex production process, high raw material cost, serious pollution of three wastes, high energy consumption and harm to human health.
In addition, carbon tetrachloride is toxic, especially in recent years, carbon tetrachloride has been recognized as a consumer of the atmospheric ozone layer.
During the period of 1995, developed countries shut down the equipment for producing chlorinated rubber with carbon tetrachloride while implementing the Montreal Protocol, and environmental protection production methods came into being.
Developed countries have completely eliminated the production method of carbon tetrachloride.
Advanced technology used now: connecting artificial natural rubber for chlorination reaction. By controlling the reaction conditions, the shortcomings of traditional methods are overcome and the environmental protection problem is solved.
There are mainly water-phase chlorination technology represented by manufacturers abroad, solvent technology adopted by Bayer Company in Germany, and water-phase chlorinated rubber of Fenghua Yulong Chemical Company in China.
Aqueous chlorination technology acidifies natural rubber to a certain pH value with hydrochloric acid solution at room temperature, and then adds a certain proportion of surfactant to prepare a stable aqueous solution.
At the beginning of the reaction, the catalyst was added, and at the same time, it was chlorinated at 20℃ ~ 40℃ for a certain time under the irradiation of ultraviolet light, and then it was deeply chlorinated at 40℃ ~ 70℃.
After the reaction, post-treatments such as deacidification, neutralization, washing and drying were carried out to obtain chlorinated rubber with chlorine content greater than 65, which can be completely dissolved in organic solvents.
Xu Electrochemical Company, Guo Ce and Fenghua Yulong, which have independent intellectual property rights in China, all chlorinated rubber in this way, but the differences between them are different raw materials, different surfactants and different specific process conditions.
So all kinds of performances are different.
Bayer is called the most perfect technology in the world.
In the carbon tetrachloride solution of natural rubber, it is added after chlorination reaction, and carbon tetrachloride is separated by distillation to remove impurities.
The quality is returned to the chlorination system for reuse.
Carrying out water precipitation on chlorinated rubber solution, precipitating chlorinated rubber in water, washing, drying and crushing to obtain the product.
After dehydration and drying, the final product and aqueous solution are returned to the distillation system for reuse.
The production capacity of chlorinated rubber in Bayer company 1996 was 10000 t/a, and the consumption quota of carbon tetrachloride was 2.03kg/t after adopting this improved new process, which reflected the advanced technology.
The advantages of this new technology are: (1) the consumption quota of carbon tetrachloride is extremely low, which meets the international environmental protection requirements1995; (2) The content of carbon tetrachloride in the product is extremely low, only 10.4%.
The average molecular weight of chlorinated rubber is 5000 ~ 20000.
The tensile strength of unplasticized chlorinated rubber is very high, even when the deformation speed is low, it can reach 39.24MPa, but the relative elongation is extremely low.
The strength of plasticized chlorinated rubber is related to the type and degree of plasticization of plasticizer.
Like other chlorinated polymers, chlorinated polymers have high chemical stability.
In view of the fact that chlorinated rubber is basically not used without plasticizer, the chemical stability of its film, like its strength performance, largely depends on the types and dosage of plasticizer, colorant, filler and stabilizer (the film produced by chlorinated rubber alone is hard and brittle, and this unplasticized polymer is only used for printing ink because the film produced is very thin).
Like most highly chlorinated polymers, chlorinated rubber is easy to form gel without plasticizer. The formation mechanism of gel is complex and related to the type of complexing agent.
Among them, dehydrochlorination with autocatalytic properties leads to crosslinking and gel formation.
Most stabilizers act like acid absorbents, which can prevent autocatalytic reactions.
Chlorinated rubber can be used with a variety of natural resins and rubbers. The hardness and wear resistance of products can be improved in most cases after being used in combination with resin.
This is very important for coatings and adhesives.
Because it requires high creep resistance.
Chlorinated rubber is less used for extruding or molding products. Its main purpose is to classify different models according to relative molecular weight or viscosity, and it is suitable for inks, coatings and adhesives. Generally, products with low viscosity (0.0 1Pas) are mainly used as ink agents. Medium viscosity (0.0 1 ~ 0.0as) products are mainly used to prepare coatings.
High viscosity (0. 1t ~ 0. As) products are mainly used as adhesives. According to the actual application at home and abroad, they are mainly used as medium viscosity products for coatings.
The main application fields of coatings are traffic coatings, ship coatings, container coatings, architectural coatings, swimming pool coatings and flame retardant coatings.
Pavement marking paint, also known as traffic paint, is a special application field of chlorinated rubber.
The coating based on chlorinated rubber is wear-resistant, quick-drying and eye-catching on concrete and asphalt pavement.
They have excellent adhesive properties and can withstand the influence of chemicals and abrasives used in snowy days and when there is a thin ice layer on the ground.
In Britain, it has been stipulated that chlorinated rubber must be used to mark airports.
In addition, chlorinated rubber will not burn because of its high chlorine content.
Therefore, it is a valuable raw material for fireproof and anticorrosive coatings.
This coating has been widely used in refineries.
In terms of adhesives, chlorinated rubber is basically not used as an independent film former, but as a modifier.
Used to improve the properties of adhesives such as neoprene, rubber and polyurethane.
Modification with chlorinated rubber can make these adhesives more universal.
Chlorinated rubber in the United States is mainly used for paints, of which traffic paint accounts for 46%. Unlike other countries, 60% of chlorinated rubber in chlorinated rubber paint is used for marine paints.
Chlorinated rubber in China is mainly used in marine paint, traffic paint, container paint, ink agent, outdoor storage tank paint, building paint and adhesive.
The specific manufacturers are Shanghai Lin Kai Paint Factory, Tianjin COSCO Kansai Paint, Shanxi Dongfanghong, Wuhan Shuanghu, etc.
At present, the main companies producing chlorinated rubber in the world are ICI Company in Britain, Bayer Company in Germany, Caffaro Company in Italy, Hercules Company in the United States, Xudian Company, Sanyo National Policy Pulp Company, Paper Co., Ltd. and so on.
Domestic enterprises: Fenghua Yulong Chemical New Materials Co., Ltd., Puyang Chemical Co., Ltd., Yixing Changji Li Chemical Co., Ltd., Jiangsu Anbang Electrochemical Co., Ltd., Puyang Chemical Co., Ltd., Anhui Chemical Research Institute and other consumption quotas.
Rank (kg/t) natural rubber 375 carbon tetrachloride (more than 98%) 750 caustic soda (30%) ~ 7000 iodine15 (more than 95%) 1550 Chlorinated rubber is obtained by dissolving plasticized natural rubber in carbon tetrachloride or dichloroethane and introducing drying reaction under the action of catalyst.
Chlorinated rubber is not rubbery, but dendritic, and its relative density is 1.5~` 1.7. Softening and decomposing at 135~ 140℃, soluble in benzene, dichlorobenzene, tetrachlorobenzene, ethyl acetate, etc. To form a relatively stable solution with an appropriate viscosity.
Chlorinated rubber has the characteristics of aging resistance, acid resistance, alkali resistance, seawater resistance and incombustibility, and the adhesive prepared from it can be used to bond rubber with metal, leather, wood and fabric.
Chlorinated rubber can also be used as a modifier to modify chloroprene rubber, so as to improve the adhesive strength, high temperature creep and other properties.
With the obvious improvement of cohesion of chloroprene adhesive film, the bonding performance is enhanced.
The adhesion to hard PVC is nearly 10 times higher than that of unmodified chloroprene adhesive.