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CN-121991422-A - Modification process of liquid chloroprene rubber

CN121991422ACN 121991422 ACN121991422 ACN 121991422ACN-121991422-A

Abstract

The invention discloses a modification process of liquid neoprene, and relates to the technical field of 111. The liquid chloroprene rubber modification process comprises, by mass, 500 parts of medium-crystalline mercaptan-regulated solid chloroprene rubber, 500 parts of renewable vegetable oil-based polyester, 20-30 parts of bio-based composite functional auxiliary agent and 5-8 parts of bio-based triacetate, wherein the bio-based composite functional auxiliary agent consists of tea polyphenol derivatives, polylactic acid oligomers and modified soy protein isolating agents, and the process comprises the following steps of low Wen Yusu refining-classification grinding pretreatment, bio-based composite auxiliary agent pre-dispersion, ultrasonic auxiliary-anchor frame type stirring collaborative blending, vacuum homogenization-low-temperature cooling post-treatment. The invention realizes the comprehensive improvement of low temperature resistance, aging resistance and viscosity stability of the product in the whole physical process through the innovative combination of the biological-based composite auxiliary agent and the low temperature synergistic process.

Inventors

  • CHEN XIANGKUN

Assignees

  • 珠海市宏元祥景合成材料有限公司

Dates

Publication Date
20260508
Application Date
20260323

Claims (10)

  1. 1. The modification process of the liquid chloroprene rubber is characterized by comprising, by mass, 500 parts of medium-crystalline mercaptan-regulated solid chloroprene rubber, 500 parts of renewable vegetable oil-based polyester, 20-30 parts of bio-based composite functional auxiliary agent and 5-8 parts of bio-based triacetate, wherein the bio-based composite functional auxiliary agent consists of 5-8 parts of tea polyphenol derivative, 10-15 parts of polylactic acid oligomer and 5-7 parts of modified soy protein isolating agent, and the process comprises the following steps: S1, preprocessing, namely putting solid chloroprene rubber into an internal mixer, controlling the rotating speed of a rotor to be 30-40r/min, the temperature to be 40-50 ℃, the filling coefficient to be 0.6-0.7 and the plasticating time to be 15-20min, and then carrying out primary coarse crushing and secondary fine crushing, spraying a modified soy protein isolating agent aqueous solution with the concentration of 5% in the crushing process, and controlling the water content of rubber particles to be less than or equal to 0.3%; S2, pre-dispersing, namely adding vegetable oil-based polyester and bio-based triacetin into a stainless steel auxiliary preparation tank, stirring at a rotating speed of 60-80r/min for 10-15min, heating to 50-55 ℃, adding tea polyphenol derivative and polylactic acid oligomer, heating to 60 ℃, and stirring for 20-25min to form a compound auxiliary system; s3, synergistic blending, namely sucking rubber particles into a 3m3 stainless steel stirring tank, enabling the vacuum degree in the tank to reach-0.70 to-0.75 MPa, sucking a composite auxiliary agent system, stirring at a rotating speed of 40-50r/min, simultaneously starting an ultrasonic device with the speed of 200-300W and 20-30kHz, and controlling the temperature in the tank to be 55-65 ℃ for synergistic effect for 8-12 hours; S4, cooling and post-treatment, namely, maintaining the stirring rotation speed at 30r/min, homogenizing at 0.3-0.5MPa for 30-40min, cooling the materials to be less than or equal to 45 ℃, quantitatively packaging after the materials are detected to be qualified, wherein the content of active ingredients in the final product is more than or equal to 99.5%, the viscosity of the final product is 15000-22000mPa, the viscosity of the final product is S (25 ℃) and the flash point of the final product (open cup) is more than or equal to 230 ℃.
  2. 2. The process for modifying liquid neoprene according to claim 1, wherein the solid neoprene has a mooney viscosity ML1+4 (100 ℃) of 45-60 and is dried at a high temperature of 120 ℃ x2 hours to remove VOC with a purity of 99% or more.
  3. 3. The process for modifying liquid neoprene according to claim 2, wherein the renewable vegetable oil-based polyester has a flash point of not less than 220 ℃ and a viscosity of 8000-12000 mPa-s, and meets RoHS, reach and food contact level related standards.
  4. 4. The process for modifying liquid neoprene according to claim 1, wherein the bio-based composite functional additive comprises, by mass, 22-28 parts of tea polyphenol derivative 6-7 parts, polylactic acid oligomer 12-14 parts, and modified soy protein isolating agent 6-7 parts.
  5. 5. The process for modifying liquid neoprene according to claim 1, wherein the purity of the bio-based triacetin is not less than 99.5%, the mass fraction is 6-7, the viscosity is not more than 50 mPa-s (25 ℃).
  6. 6. The process for modifying liquid neoprene according to claim 1, wherein the first coarse crushing in step S1 is carried out by using a sieve with a pore diameter of 50mm, the second fine crushing is carried out by using a sieve with a pore diameter of 5-10mm, the rotor speed of the internal mixer is 35r/min, the temperature is 45 ℃, the filling coefficient is 0.65, the plasticating time is 18min, and the pore diameter of the second fine crushing is 8mm.
  7. 7. The process for modifying liquid neoprene according to claim 1, wherein the stirring speed in S2 is 70r/min, the stirring is performed for 12min after the temperature is raised to 52 ℃, and the stirring is performed for 22min after the tea polyphenol derivative and the polylactic acid oligomer are added.
  8. 8. The process for modifying liquid neoprene according to claim 1, wherein the stirring speed in the step S3 is 45r/min, the ultrasonic power is 250W, the ultrasonic frequency is 25kHz, the temperature in the tank is 60 ℃, the synergistic action time is 10 hours, the ultrasonic device acts on the middle area of the material in the tank, and the contact surface of the ultrasonic probe and the material is made of S316L stainless steel.
  9. 9. The process for modifying liquid neoprene according to claim 1, wherein the homogenizing pressure in S4 is 0.4MPa, the homogenizing time is 35min, and the material is cooled to 40 ℃.
  10. 10. The process for modifying liquid neoprene according to claim 1, wherein the 3m3 stainless steel stirring tank is equipped with an anchor frame type stirring paddle, the ratio of the diameter of the stirring paddle to the inner diameter of the tank is 0.8-0.85, the acid value of the renewable vegetable oil-based polyester is less than or equal to 0.5mgKOH/g, and the hydroxyl value is less than or equal to 10mgKOH/g.

Description

Modification process of liquid chloroprene rubber Technical Field The invention belongs to the technical field of rubber modification, in particular relates to a modification process of liquid chloroprene rubber, is particularly suitable for producing rubber products with comprehensive requirements on low temperature resistance, ageing resistance and storage stability, and can be widely applied to the fields of sealing materials, soft plastic products, food contact rubber products and the like. Background The traditional liquid chloroprene rubber modification process has the technical bottlenecks that firstly, the performance is optimized and single, the traditional process is mainly used for enhancing low temperature resistance and lacks of cooperative improvement on ageing resistance and viscosity stability, the problems of cracking, viscosity drift and the like are easily caused after long-term use, secondly, the blending efficiency is low, the traditional physical blending is required to be continuously stirred for 20-34 hours, the material mixing uniformity is poor, the batch production mode is difficult to adapt to the large-scale industrial requirements, thirdly, the auxiliary agent suitability is insufficient, a part of the process adopts a chemical stabilizer, the VOC residual risk exists, the environment protection and food contact level standard is not met, the process without adding functional auxiliary agent cannot balance the multi-performance requirements, fourthly, the pretreatment process is rough, the rubber particle size is easily caused by simple cutting and crushing, the subsequent blending effect is influenced, and the traditional chemical isolating agent has poor environment protection. The method has the advantages that the silicon rubber is used as a base material in part of the prior art, a catalyst is required to be added and vulcanization is carried out, the method belongs to a chemical-physical composite process, the modification logic difference between the silicon rubber and the chloroprene rubber is obvious, the use of chemical additives cannot meet the environmental protection requirement of food contact level, the natural rubber is used as the base material in part of the prior art, molecular chain breakage is realized through high-temperature double screw shearing at 180-260 ℃, the continuous efficiency is improved, rubber degradation is easily caused at high temperature, and the molecular weight distribution is controlled only through an anti-aging agent, so that functional modification is not realized. Disclosure of Invention The invention aims to at least solve one of the technical problems in the prior art, and provides a liquid chloroprene rubber modification process which can solve the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: The liquid chloroprene rubber modification technology disclosed by the invention comprises the following raw materials in parts by mass: substrate medium crystalline mercaptan-adjusted solid neoprene 500 parts. The neoprene is selected because of moderate crystallinity, good mechanical property and processing suitability, wherein the Mooney viscosity ML1+4 (100 ℃) is set to 45-60, the range can ensure the subsequent plasticating processing efficiency, can avoid the defect of insufficient performance caused by difficult shearing or too low shearing due to the too high Mooney viscosity, and can thoroughly remove VOC after the substrate is subjected to high-temperature drying treatment for 120 ℃ multiplied by 2 hours, thereby ensuring the purity to be more than or equal to 99 percent and laying clean foundation for the subsequent modification. 500 Parts of main modifier, namely renewable vegetable oil-based polyester. The modifier selects specifications with flash point more than or equal to 220 ℃ and viscosity of 8000-12000mPa and standard s, the high flash point characteristic improves the production safety, the proper viscosity range can form good compatibility with chloroprene rubber, the modifier is synthesized by taking renewable natural vegetable oil as a raw material, the product meets the related standards of RoHS, reach and food contact level, the environmental protection property of the product is ensured from the source, and meanwhile, the low temperature resistance and the processing fluidity of the chloroprene rubber can be effectively improved. 20-30 Parts of bio-based composite functional auxiliary agent, which consists of 5-8 parts of tea polyphenol derivative, 10-15 parts of polylactic acid oligomer and 5-7 parts of modified soybean protein isolating agent. The modified soybean protein isolating agent is a biodegradable material, replaces the traditional chemical isolating agent, avoids residual pollution, ensures that a 5% aqueous solution can form a uniform protective film in the crushing process, prevents rubber particles from agglomerati