Chlorosulfonated polyethylene (CSM) was first industrialized by Dupont in 1952.Chlorosulfonated polyethylene consists oflow density polyethyleneorHigh density polyethyleneAfter chlorination andChlorosulfonation reactionMade.It is white or yellow elastomer and can dissolve inAromatic hydrocarbonandChlorohydrocarbonInsoluble in fat and alcohol, onlyswellingInsoluble, excellent ozone resistance, atmospheric aging resistance, chemical corrosion resistance, good physical and mechanical properties, aging resistance, heat resistance and low temperature resistanceOil resistance, flame resistance, abrasion resistance, and resistanceElectrical insulation。It has a wide range of applications, only the United StatesJapanA few countries, such as Russia and China, have built installations with a global total annual production capacity of about 75000 tons, which is close to the production capacity.
It has the common properties of raw rubber and its own unique properties, excellent ozone resistance, atmospheric aging resistance, chemical corrosion resistance, good physical and mechanical properties, aging resistance, heat and low temperature resistance, oil resistance, fire resistance, wear resistance, and resistanceElectrical insulation。
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Chlorosulfonated polyethylene
Alias: Hailong Hailong hyperplon
Chlorosulfonated polyethylene is produced by chlorinationChlorosulfonation reactionBut the chlorine containing product with high saturated chemical structure is specialElastomer material, of high performance and qualitySpecial rubbervarieties.Its appearance is white or milky white elastic material, includingThermoplasticity。Because the molecular structure contains chlorosulfonyl active group, it shows high activity, especially outstanding resistance to chemical medium corrosion, ozone oxidation, oil corrosion, flame retardant and other properties, and also has resistance to weathering, heat, ion radiation, low temperatureabrasionandElectrical insulationAnd excellent mechanical properties.In the early days, CSM was mostly developed for military engineering purposes.However, due to its large permanent deformation, its application scope is also limited.
Production method
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There are two production methods of chlorosulfonated polyethylene:Solvent methodAnd gas-solid method.
Traditional solvent method:chlorine、sulfur dioxideEqual to chlorineSulfonationThe main disadvantage of the liquid phase manufacturing process of the agent is that the utilization rate of sulfur dioxide is low (20-30%), and the chlorine content of the product is only 25-45%.Sulfur content is 0.8-1.7%, and the fatal disadvantage is that it needs to be usedcarbon tetrachlorideMake solvent.In addition, the post-treatment process of the liquid phase process is complicated (exceptAcid gas, CSM coagulation and separation operations, etc.).
Gas phase method: The synthesis process was reported as early as the 1980s, but the earliest industrial unit was put into use in 2009. This process was developed by domestic companies, and the product trial production was successful in the same year. In May 2010, the gas-solid chlorosulfonated polyethylene production process passedChina Petroleum and Chemical Industry FederationAppraisal of scientific and technological achievements organized.The biggest breakthrough of gas-solid production process is that no organic solvent is used at all, and the materials of reaction gas are directly contacted, which shortens the process flow and achieves green and environmental protection.
CSM is widely used in the automobile industry abroad, but it is almost blank in China.With the acceleration of the localization of spare parts in China's automobile industry, the potential consumption of CSM in the automobile industry is huge.It is estimated that the potential demand of CSM in the automotive industry in 2005 should be at least 3000 tons.
CSM is used in industry to manufacture pipes with special propertiesTransport belt、Sealing elementAnd other products.For example, the laminated pipe made with CSM as the inner layer can be used to replace fluorohydrocarbonCryogenPermeabilityLow, suitable for refrigerant delivery pipe.When manufacturing CSM － fluororubber laminated pipe, such as addingperoxideThe peeling strength of laminated products can be greatly improved, and the laminated products are suitable for manufacturing, transportation and storagefuel oilPipes and containers.
CSM can be carried out with other rubbersBlendingModification.CSM vsFluororubberBlending can improve the processability of blended rubber.CSM vsEPDMBlending can improve the physical and mechanical properties and thermophysical characteristics of vulcanizates.Adding CSM and isoprene rubber into EVA polymer can produce the properties of skid resistance, abrasion resistance and oil resistance.CSM, PVC and PUExtruderModerate mixingPost vulcanizationCan be manufactured to improve oil resistance and resistanceozoneOfVulcanizate。
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Vulcanization system
Some people think that "MgO and ZnO are CSMvulcanizationThe statement "system" is unreasonable.About CSM andChlorinated polymerMost of the information about the coordination and vulcanization ofRubber Industry ManualIn Book Ichlorinated polyethylene And chlorosulfonated polyethylene part.However, some academic documents have plagiarized some original materials about this type (it can't be said that it is a reference, because it has not been given to my own experiment and thinking).
But it is strange to joinzinc oxide(ZnO), on the contrary, affected the curing efficiency.It indicates that zinc oxide can not only accelerate the removalHydrogen chloride（HCl）It can also cause instability of rubber.In the polymer without high activity chlorine, ZnO can only accelerate the HCL removal rate when heated (data introduction:HCLIt is not ZnO itself, but ZnCl2 produced by the reaction of Zn and Cl. See organic chemistry for the mechanism of this place<Halohydrocarbon>Chapter 1, Lewis acid on halogenated hydrocarbon).PentaerythritolWhen used alone, CSM cannot be crosslinked. Only in the presence of vulcanizing agent TRA can the vulcanization speed be greatly improved, which greatly promotesvulcanizationSpeed, butScorchSome performance
Reinforcement filling system
CSMThe difference between rubber and other rubbers is that even if no reinforcing filler is added, itsVulcanizateIt also has high staticvulcanizationstrength.This is because the vulcanization structure of CSM has unique characteristics.Side groups generated during vulcanization and crosslinkingBond polaritymutualassociationIt forms particles, which not only functions as a vulcanization network, but alsoPhysical crosslinkingPoint function.
However, fillers can still improve the processing properties of rubber compound, improve the heat resistance and wear resistance of vulcanizate, and reduce costs.The reinforcing fillers commonly used are carbon blackcalcium carbonate、kaolin，diatomite, white carbon blacktalcEtc.The role played by fillers depends on their particle size. The finer the particles, the better the performance of the vulcanizate obtained.Among inorganic fillers, white carbon black can guarantee the highestHeat resistance。Diatomite can improve thetear strength And improve its rigidity and hardness.
To improveVulcanizateOfWeatherabilityKaolin should be used, and it has the following characteristics: good dielectric property, no reduction after moisture absorption, and excellent dynamic performance.In light colored products, it can be filled effectivelybarium sulfateAndLithopone，Titanium dioxideIt can improve the brightness and weather resistance of vulcanizate color.
CSM vulcanizate with filler has highchemical stability。Hot cracking carbon blackBariteIt can make the vulcanizate obtain the best salt and acid resistance.For sulfuric acid resistance, the filler with the best effect is hot cracking carbon blackkaolinBarite, diatomite, etc.For nitric acid resistance, it is hot cracking carbon black.
Plasticizing system
stayChlorosulfonated polyethylene rubberPlasticizer is used in order to improve the processing performance of rubber compoundVulcanizateLow temperature performance, as well as improve its elasticity and reduce hardness.The most commonly used petroleum oil, ointment and ester plasticizer in CSM compound.The dosage can be slightly more than that in other rubbers.The dosage of plasticizer should be reduced to a minimum in the vulcanizate to be in contact with chemicals.
For rubber to be used at low temperature, it is better to use ester plasticizer.Such as DOP, DOA, DOS, etc.Chlorinated paraffinIn other rubbers asFlame retardantIn addition to being flame retardant in CSM, it can also improvetensile strength And after improving heat resistance and agingelongationRetention rate of,Low temperature performanceAlso good.When the degree of chlorination is about 40%, the flame resistance is improved, but the low temperature performance is worse.
Stable protection system
The function of stabilizer is to preventChlorosulfonated polyethylene rubberDegradation occurs during production, storage and use.Stearate, organic tinmagnesium oxideEtc.Magnesium oxide is a good and common stabilizer, which can be effectively absorbedHydrogen chlorideAnd other by-products.About magnesium oxideActivityAndVulcanizateSee Table 2-1 for performance relationship
Table 2-1 Effect of MgO activity on physical properties of CSM
CSM rubber vulcanizate usually does not need to be added except for high temperature exposureantioxidant。Over 120 degrees,Antioxidant NBCIt is the most effective stabilizer and has the function of activating accelerator, but it also damages the processing safety.
Processing aids
In order to improve the performance of CSM rubber in the openercalenderWaxes with good compatibility with CSM, such asMicrocrystalline wax。In addition, petroleum andparaffin waxThe amount of wax is limited due to its spouting property.Use below 77 degreespolyethylene glycol, used above 77 degreesPolyethylene waxIt is effective as a processing aid.AndNitrile rubber、butadiene styrene rubber、Cis-1,4-polybutadiene rubberIn addition to reducing cost and improving adhesion, it can also improve processing performance, especially cis-1,4-polybutadiene rubberQualityThe processing performance will be improved.
In order to improve the self-adhesiveness of rubber, low molecular weightGumalon-Printing resin.Add about 10 parts by weightpetroleum resin It can also improve the self-adhesiveness of rubber.
Due to its good color stability, chlorosulfonated polyethylene can be used to produce various color products with good performance.Because many organic colorants in CSMvulcanizationIn the process, it will react with polymers, so most colorants suitable for CSM are inorganic compounds.Colorants not onlyVulcanizateIt has coloring effect and can also protect CSM from ultraviolet light.
