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CN-122011605-A - Preparation method of rubber for low-density closed-cell foaming automobile sealing strip

CN122011605ACN 122011605 ACN122011605 ACN 122011605ACN-122011605-A

Abstract

The invention discloses a preparation method of rubber for a low-density closed-cell foaming automobile sealing strip, which relates to the technical field of rubber preparation and comprises the following raw materials of ethylene propylene diene monomer, zinc oxide, an activating auxiliary agent, carbon black N550, nano hydrotalcite, maleic anhydride grafted ethylene propylene diene monomer, modified hydrogenated polybutadiene oil, azodicarbonamide, sulfur, N-cyclohexyl-2-benzothiazole sulfenamide, triallyl isocyanurate, an antioxidant, modified zinc stearate and modified zinc borate. According to the invention, the modified zinc stearate is added, so that the azodicarbonamide can be efficiently activated at a low temperature, the foaming is more fully and uniformly performed to reduce the density of rubber, the supporting force of the cell wall can be enhanced by the nano rigid shell to avoid collapse deformation, the dispersion uniformity of the alkyl phosphoric acid imide in the nonpolar ethylene propylene diene monomer is improved, meanwhile, the alkyl phosphoric acid imide is more strongly combined with a rubber matrix, the foaming fineness is optimized, the agglomeration and the frosting are reduced, and the booster rubber forms a stable and uniform closed-cell structure.

Inventors

  • WANG JIANKUI
  • Ye Siyan
  • WANG RUISEN

Assignees

  • 河北世翔密封件有限公司

Dates

Publication Date
20260512
Application Date
20260327

Claims (10)

  1. 1. The preparation method of the rubber for the low-density closed-cell foamed automobile sealing strip is characterized by comprising the following steps of: S1, adding ethylene propylene diene monomer into an internal mixer for plasticating, adding zinc oxide and an activating auxiliary agent for mixing, adding carbon black N550, nano hydrotalcite and maleic anhydride grafted ethylene propylene diene monomer for mixing, adding modified hydrogenated polybutadiene oil for mixing, adding an antioxidant, modified zinc stearate and modified zinc borate for mixing, discharging rubber to obtain rubber material, thinning the rubber material, and naturally cooling the pressed rubber material to obtain a rubber sheet; S2, putting the rubber sheet into a rubber mixing machine, wrapping the rubber sheet, then thinning the rubber sheet, adding azodicarbonamide, rubber tapping, adding sulfur, rubber tapping, adding N-cyclohexyl-2-benzothiazole sulfenamide, rubber tapping, adding triallyl isocyanurate, rubber tapping to obtain a mixture, thinning the mixture, discharging to obtain a mixture rubber sheet, cooling the mixture rubber sheet, and vulcanizing to obtain a vulcanized material; S3, conveying the vulcanized material into a three-stage water cooling tank for cooling and shaping, and drawing the cooled vulcanized material to cut the vulcanized material into sections to obtain the rubber for the low-density closed-cell foaming automobile sealing strip; The low-density closed-cell foaming rubber for the automobile sealing strip comprises, by weight, 95-105 parts of ethylene propylene diene monomer rubber, 2.5-3.5 parts of zinc oxide, 0.7-0.9 part of an activating auxiliary agent, 10-14 parts of carbon black N550, 5-7 parts of nano hydrotalcite, 0.8-1.2 parts of maleic anhydride grafted ethylene propylene diene monomer rubber, 14-16 parts of modified hydrogenated polybutadiene oil, 3.5-4.5 parts of azodicarbonamide, 0.6-0.7 part of sulfur, 0.6-0.8 part of N-cyclohexyl-2-benzothiazole sulfenamide, 0.25-0.35 part of triallyl isocyanurate, 0.7-0.9 part of an antioxidant, 1.8-2.2 parts of modified zinc stearate and 1.6-2 parts of modified zinc borate.
  2. 2. The method for producing a rubber for a low-density closed-cell foamed automobile weather strip according to claim 1, wherein the antioxidant consists of pentaerythritol tetrakis [ β - (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ] and tris (2, 4-di-t-butylphenyl) phosphite.
  3. 3. The method for producing a rubber for a low-density closed-cell foamed automobile weather strip according to claim 2, wherein the mass ratio of pentaerythritol tetrakis [ β - (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ] to tris (2, 4-di-t-butylphenyl) phosphite is 5:3.
  4. 4. The method for producing a rubber for a low-density closed-cell foamed automobile weather strip according to claim 2, wherein the activating aid is one of stearic acid and palmitic acid.
  5. 5. The method for preparing the rubber for the low-density closed-cell foamed automobile sealing strip, which is characterized by comprising the following steps of adding hydrogenated polybutadiene oil into a reaction kettle, introducing nitrogen for stirring, adding a boron nitrogen heterocyclic alkyl phosphine chelating agent for stirring, adding a perfluorinated cyclic ether end-capped cycloolefin monomer and benzoyl peroxide for stirring, and adding thiophosphate cage type POSS for stirring to obtain the modified hydrogenated polybutadiene oil.
  6. 6. The method for preparing the rubber for the low-density closed-cell foamed automobile sealing strip according to claim 5, wherein the mass ratio of the hydrogenated polybutadiene oil to the boron nitrogen heterocyclic alkyl phosphine chelating agent to the phosphorothioate cage type POSS to the perfluorinated cyclic ether end-capped cycloolefin monomer to the benzoyl peroxide is 100:2.5:1.5:2:0.1.
  7. 7. The method for producing a rubber for a low-density closed-cell foamed automobile weather strip according to claim 1, wherein the production of the modified zinc stearate comprises the steps of: A1. Putting zinc stearate into an air flow pulverizer for pulverization, and putting the pulverized zinc stearate into a vacuum drying oven for drying to obtain dry zinc stearate powder; A2. And (3) putting the dried zinc stearate powder into a mixer, adding alkenyl zirconium naphthenate chelate, stirring, adding methacrylate POSS and dicumyl peroxide, stirring, adding long-chain alkyl phosphate imide, and stirring to obtain the modified zinc stearate.
  8. 8. The method for producing a rubber for a low-density closed-cell foamed automobile weather strip according to claim 7, wherein the mass ratio of the dry zinc stearate powder, the alkenyl zirconium naphthenate chelate, the methacrylate-based POSS, the dicumyl peroxide and the long-chain alkyl phosphoric acid imide is 100:4:3:0.2:2.2.
  9. 9. The method for producing a rubber for a low-density closed-cell foamed automobile weather strip according to claim 1, wherein the production of the modified zinc borate comprises the steps of: B1. vacuum drying zinc borate, and putting the dried zinc borate into a pulverizer for pulverization to obtain zinc borate powder; B2. and (3) putting zinc borate powder into a mixer, adding fluorinated alkyl phosphine nitrogen heterocyclic chelate, stirring, adding cycloalkenyl caged thiophosphate and dicumyl peroxide, stirring, adding alkyl borazine micromolecule, and stirring to obtain modified zinc borate.
  10. 10. The method for preparing the rubber for the low-density closed-cell foamed automobile sealing strip according to claim 9, wherein the mass ratio of zinc borate powder to fluorinated alkyl phosphine nitrogen heterocyclic chelate to alkyl borane small molecules to cycloolefin cage thiophosphate to dicumyl peroxide is 100:2:3:2.5:0.2.

Description

Preparation method of rubber for low-density closed-cell foaming automobile sealing strip Technical Field The invention relates to the technical field of rubber preparation, in particular to a preparation method of rubber for a low-density closed-cell foaming automobile sealing strip. Background The rubber is a high-molecular polymer material with high elasticity, and is mainly divided into natural rubber obtained from natural plants (such as rubber trees) and artificial synthetic rubber obtained through chemical synthesis, and the unique molecular chain structure of the rubber can enable the rubber to be obviously deformed under the action of external force and recover the rubber after the external force is removed, so that the rubber is a key base material for manufacturing various elastic products such as tires, sealing elements, shock absorbing products and the like. The traditional rubber for the sealing strip has the problems of uneven foaming, higher density, poor closed pore effect and more communicating pores, so that the waterproof performance is poor, the water absorption is high, meanwhile, foam holes are easy to collapse and crack, filler is easy to agglomerate and disperse unevenly, the mixing extrusion processing fluidity of the sizing material is poor, the situations of migration and frosting of the auxiliary agent and whitening of the surface are easy to occur, and the defects of insufficient crosslinking density, poor compression rebound resilience performance, low mechanical strength and weak heat aging resistance are caused. Based on the above, the invention provides a preparation method of rubber for a low-density closed-cell foaming automobile sealing strip. Disclosure of Invention The invention mainly aims to provide a preparation method of rubber for a low-density closed-cell foamed automobile sealing strip, which has low apparent density and high closed-cell rate, and is applied to the preparation method of rubber for the low-density closed-cell foamed automobile sealing strip. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the invention provides a preparation method of rubber for a low-density closed-cell foaming automobile sealing strip, which comprises the following steps: S1, adding ethylene propylene diene monomer into an internal mixer for plasticating, setting the temperature to be 65-70 ℃, the rotating speed to be 60rpm, the pressurizing pressure to be 0.3-0.5MPa, plasticating for 2 minutes, adding zinc oxide and an activating auxiliary agent for mixing, mixing for 2 minutes, adding carbon black N550, nano hydrotalcite and maleic anhydride grafted ethylene propylene diene monomer for mixing, mixing for 4 minutes, adding modified hydrogenated polybutadiene oil for mixing, mixing for 3 minutes, adding an antioxidant, modified zinc stearate and modified zinc borate for mixing, mixing for 3 minutes, heating the internal mixer to be 105 ℃, discharging rubber, obtaining rubber material, pressing the rubber material to have the thickness of 8-10mm, and naturally cooling the pressed rubber material to 25 ℃ to obtain a rubber sheet. S2, placing the rubber sheet into a rubber mixing machine, setting the temperature to 55-65 ℃, the roll spacing to 0.5-1.0mm, the rotating speed to 25-30rpm, carrying out thin pass on the rubber sheet for 2 times after a roller is wrapped, adding azodicarbonamide, cutting rubber for 3 times, adding sulfur, cutting rubber for 3 times, adding N-cyclohexyl-2-benzothiazole sulfenamide, cutting rubber for 3 times, adding triallyl isocyanurate, cutting rubber for 3 times, obtaining a mixture, carrying out thin pass on the mixture for 6 times, adjusting the roll spacing to 4-5mm, discharging, obtaining the mixture rubber sheet, cooling the mixture rubber sheet to 25 ℃, then vulcanizing, firstly, delivering the mixture rubber sheet into a microwave vulcanizing tunnel, vulcanizing at the microwave frequency of 2450MHz, the temperature of 170-178 ℃, staying for 40-60 seconds, delivering the mixture rubber sheet into a hot air vulcanizing box, setting the temperature to 185-195 ℃ and staying for 3-4 minutes, thus obtaining the vulcanized material. S3, conveying the vulcanized material into a three-stage water cooling tank for cooling and shaping, setting the temperature of cooling water to be 70 ℃, 45 ℃ and 25 ℃ in sequence, gradually reducing the temperature for 5-8 minutes, and cutting the vulcanized material into sections at a traction speed of 1-2m/min after cooling to obtain the rubber for the low-density closed-cell foaming automobile sealing strip. The low-density closed-cell foaming rubber for the automobile sealing strip comprises, by weight, 95-105 parts of ethylene propylene diene monomer rubber, 2.5-3.5 parts of zinc oxide, 0.7-0.9 part of an activating auxiliary agent, 10-14 parts of carbon black N550, 5-7 parts of nano hydrotalcite, 0.8-1.2 parts of maleic anhydride grafted ethylene propylene diene m