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CN-122011637-A - Modified PVC valve suitable for strong acid environment and preparation method thereof

CN122011637ACN 122011637 ACN122011637 ACN 122011637ACN-122011637-A

Abstract

The invention discloses a modified PVC valve suitable for a strong acid environment and a preparation method thereof. The preparation method comprises the steps of firstly synthesizing a polymerization auxiliary agent through free radical copolymerization of butyl methacrylate, glycidyl methacrylate, 2-trifluoroethyl methacrylate and gamma-methacryloxypropyl trimethoxy silane, then carrying out melt mixing on the auxiliary agent, chlorinated polyvinyl chloride resin, montmorillonite filler, stabilizer, toughening agent and processing auxiliary agent to obtain a functional master batch, and finally blending the master batch with the resin and carrying out injection molding. According to the invention, through the interfacial bonding synergistic effect of the acid-repellent property of the fluorine-containing monomer and the silane coupling agent, a stable 'in-situ protective layer' is constructed in the material, and the acid-resistant permeability, the environmental stress cracking resistance and the long-term dynamic sealing property of the valve are obviously improved. The valve has excellent corrosion resistance durability and structural integrity in strong acid environment, and is suitable for harsh working conditions such as chemical industry, electroplating and the like.

Inventors

  • YANG XIAOYUN
  • REN HONGHAO

Assignees

  • 浙江东生环境科技有限公司

Dates

Publication Date
20260512
Application Date
20260227

Claims (8)

  1. 1. The preparation method of the modified PVC valve suitable for the strong acid environment is characterized by comprising the following steps of: Step 1, dissolving butyl methacrylate, glycidyl methacrylate, 2-trifluoroethyl methacrylate and gamma-methacryloxypropyl trimethoxy silane in toluene, and adding an initiator under the protection of nitrogen atmosphere to perform free radical copolymerization reaction to obtain a polymerization auxiliary agent; Step 2, adding a polymerization auxiliary agent, chlorinated polyvinyl chloride resin, montmorillonite filler, a stabilizer, a toughening agent and a processing auxiliary agent into a double-screw extruder for melt mixing to prepare functional master batch; And step 3, mixing the functional master batch with chlorinated polyvinyl chloride resin, drying at 80-120 ℃ for 2-6 hours, and then performing injection molding by using an injection molding machine to obtain the modified PVC valve.
  2. 2. The method for preparing the modified PVC valve suitable for the strong acid environment according to claim 1, wherein the mass ratio of butyl methacrylate, glycidyl methacrylate, 2-trifluoroethyl methacrylate and gamma-methacryloxypropyl trimethoxysilane in the step 1 is (40-60): 5-15): 5-20): 3-10.
  3. 3. The method for preparing a modified PVC valve according to claim 1, wherein the initiator in the step 1 is azobisisobutyronitrile or benzoyl peroxide.
  4. 4. The method for preparing a modified PVC valve according to claim 1, wherein the temperature of the radical copolymerization reaction in the step 1 is 60-80 ℃ and the reaction time is 6-12h.
  5. 5. The method for preparing the modified PVC valve suitable for the strong acid environment according to claim 1, wherein the addition amounts of the polymerization auxiliary agent, the montmorillonite, the stabilizer, the toughening agent and the processing auxiliary agent in the step 2 are respectively (0.5% -5.0%), the (1% -10%), the (0.8% -3.0%), the (5.0% -15.0%) and the (0.5% -2.5%) of the chlorinated polyvinyl chloride resin.
  6. 6. The method for preparing a modified PVC valve according to claim 1, wherein the temperature of the melt-kneading in the step 2 is 160-200 ℃.
  7. 7. The method for preparing a modified PVC valve according to claim 1, wherein the temperature of the injection molded cylinder in the step 3 is 180-220 ℃.
  8. 8. The method for preparing the modified PVC valve suitable for the strong acid environment according to claim 1, wherein the mass ratio of the functional master batch to the chlorinated polyvinyl chloride resin in the step 3 is (5-30) (70-95).

Description

Modified PVC valve suitable for strong acid environment and preparation method thereof Technical Field The invention relates to the technical field of polymer material processing, in particular to a modified PVC valve suitable for a strong acid environment and a preparation method thereof. Background In the industrial fields of chemical industry, metallurgy, electroplating, wet smelting, acid washing and the like, the valve is used as a key component in a fluid conveying and controlling system and is in a strong acid medium action environment for a long time, and high requirements are put on corrosion resistance, structural stability and service life of the valve. Polyvinyl chloride (PVC) and its modified materials are widely used in acidic medium conveying pipelines and valve systems because of their light weight, good processability and certain corrosion resistance. However, as the working conditions become more and more severe, the conventional PVC valves gradually suffer from insufficient durability, especially in strong acid environments such as high concentration hydrochloric acid and the like, and under conditions of mechanical load or assembly stress. In the prior art, the mechanical property and the processing property of the modified PVC valve are improved by introducing filler, a toughening agent or a stabilizer, but under the long-term action of strong acid, an acidic medium is still easy to permeate along micropores, filler interfaces or processing defects in the material, so that the material performance is degraded. Simultaneously, under the coupling effect of stress and chemical medium, the PVC valve body is easy to generate environmental stress cracking, so that the valve is in sealing failure or even in structural failure, and the operation safety of the system is seriously influenced. In addition, the auxiliary agent used in the partial modification system has the problems of migration or failure in a strong acid environment, and long-term stable protection is difficult to realize. Therefore, how to effectively inhibit penetration of strong acid media, improve interface stability and remarkably enhance environmental stress cracking resistance while maintaining good processing performance of PVC materials is still a technical problem to be solved in the field of modified PVC valves. Disclosure of Invention Aiming at the problems, the invention provides a modified PVC valve suitable for a strong acid environment and a preparation method thereof, and solves the technical problems that the modified PVC valve is easy to crack due to the permeation of an acid medium and the coupling effect of stress in a high-concentration hydrochloric acid environment and has insufficient durability. The invention can be realized by the following technical scheme: The preparation method of the modified PVC valve suitable for the strong acid environment comprises the following steps: Step 1, dissolving butyl methacrylate, glycidyl methacrylate, 2-trifluoroethyl methacrylate and gamma-methacryloxypropyl trimethoxy silane in toluene, and adding an initiator under the protection of nitrogen atmosphere to perform free radical copolymerization reaction to obtain a polymerization auxiliary agent; Step 2, adding a polymerization auxiliary agent, chlorinated polyvinyl chloride resin, montmorillonite filler, a stabilizer, a toughening agent and a processing auxiliary agent into a double-screw extruder for melt mixing to prepare functional master batch; And step 3, mixing the functional master batch with chlorinated polyvinyl chloride resin, drying at 80-120 ℃ for 2-6 hours, and then performing injection molding by using an injection molding machine to obtain the modified PVC valve. Preferably, in the step 1, the mass ratio of the butyl methacrylate to the glycidyl methacrylate to the 2, 2-trifluoroethyl methacrylate to the gamma-methacryloxypropyl trimethoxysilane is (40-60): 5-15): 5-20): 3-10. Preferably, the initiator in the step 1 is azobisisobutyronitrile or benzoyl peroxide. Preferably, the temperature of the free radical copolymerization reaction in the step 1 is 60-80 ℃ and the reaction time is 6-12h. Preferably, the addition amounts of the polymerization auxiliary agent, the montmorillonite, the stabilizer, the toughening agent and the processing auxiliary agent in the step 2 are respectively (0.5% -5.0%), the (1% -10%), the (0.8% -3.0%), the (5.0% -15.0%) and the (0.5% -2.5%) of the mass of the chlorinated polyvinyl chloride resin. Preferably, the temperature of the melt-kneading in the step 2 is 160-200 ℃. Preferably, the temperature of the injection molded material cylinder in the step 3 is 180-220 ℃. Preferably, the mass ratio of the functional master batch to the chlorinated polyvinyl chloride resin in the step 3 is (5-30) (70-95). The beneficial effects of the invention are as follows: The invention designs and prepares a polymerization auxiliary agent by carrying out free radical copolymerization on buty