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CN-115556280-B - Preparation method of directional conductive silicon rubber sealing gasket

CN115556280BCN 115556280 BCN115556280 BCN 115556280BCN-115556280-B

Abstract

The invention relates to the technical field of conductive rubber, in particular to a preparation method of a directional conductive silicon rubber sealing gasket. The method comprises the specific steps of fixing wavy metal wires on a frame at equal intervals, placing the metal wire frame into an oscillator containing an acid solution, taking out and cleaning the metal wire frame after vibration is finished, taking out and airing the metal wire frame after cleaning is finished, uniformly spraying an adhesive on the surface of the metal wire, placing the metal wire frame into an oven for drying after spraying is finished, tightly stacking the metal wire frame in a mold along the same direction, sealing a gap part by adopting a sealant after sealing treatment, injecting silicon rubber into the mold prepared in the step S4 by adopting a vacuum glue injection machine, vulcanizing after pouring is finished, taking out a pouring blank, and cutting according to requirements, wherein the cutting direction is perpendicular to the arrangement direction of the metal wires. The operation method is simple, the industrial mass production is easy to realize, and the prepared silicon rubber sealing gasket has good conductivity and stability.

Inventors

  • WANG YUEXIANG
  • DONG CHUNYU
  • YANG XIAOJIONG
  • HAN YANGYANG

Assignees

  • 中国电子科技集团公司第三十三研究所

Dates

Publication Date
20260512
Application Date
20221014

Claims (8)

  1. 1. A preparation method of an oriented conductive silicon rubber sealing gasket is characterized by comprising the following specific steps: s1, arranging wires, namely equidistantly fixing wavy metal wires on a frame; S2, etching treatment, namely placing the wire frames arranged in the S1 into an oscillator containing an acid solution, taking out and cleaning the wire frames after the oscillation is finished, and taking out and airing the wire frames after the cleaning is finished; s3, adhesive treatment, namely uniformly spraying the wire frame dried in the S2 on the surface of the wire by using an adhesive, and putting the wire frame into an oven for drying after the spraying is finished; S4, fixing the frames, namely tightly stacking the metal wire frames dried in the S3 in a mold along the same direction, and sealing the gap part by adopting a sealant after sealing treatment to prepare the mold; S5, casting molding, namely injecting the silicon rubber into the mold prepared in the S4 by using a vacuum glue injection machine, and vulcanizing after casting is completed to prepare a casting blank; S6, cutting, namely taking out the casting blank prepared in the step S5, and cutting the casting blank into a rubber gasket with a certain shape and size according to requirements, wherein the cutting direction is perpendicular to the arrangement direction of the metal wires; The metal wires in the S1 comprise austenitic stainless steel wires, aluminum wires, copper wires or alloy wires thereof, wherein the wire diameters of the metal wires are 0.1 mm-0.2 mm, the distance between the metal wires is 0.8 mm-1.2 mm, and the thickness of the fixed frame is 0.8 mm-1.2 mm; The acid solution in the step S2 is hydrofluoric acid solution, the solubility of the hydrofluoric acid solution is 5% -15%, the temperature of the solution is 30 ℃ -50 ℃, the oscillation time is 0.5-2 h, and the metal wire frame is cleaned in an ultrasonic cleaner by clean water for 5-10 min.
  2. 2. The preparation method of the directional conductive silicone rubber sealing gasket is characterized in that the adhesive in the S3 is a single-component or double-component silicone adhesive, the single-component silicone adhesive is a mixture of hydroxyl-terminated silicone rubber, methyltrimethoxysilane, organotin and toluene, the proportion of each component is 100:4-8:0.2-0.6:1-5, the proportion of each component A is a mixture of hydroxyl-terminated silicone rubber, hydrogen-containing silicone oil and toluene, the proportion of each component A is 100:4-7:3-9, the proportion of each component B is a mixture of hydroxyl-terminated silicone rubber, chloroplatinic acid compound and toluene, the proportion of each component is 100:0.2-0.5:1-5, the spraying pressure is 0.2 MPa-0.5 MPa, the spraying time is 30S 120S, the drying temperature is 100-130 ℃, and the drying time is 2-4 h.
  3. 3. The method for preparing the directional conductive silicone rubber sealing gasket of claim 1, wherein the silicone rubber in the step S5 is AB bi-component liquid silicone rubber, the mixing ratio of A, B components is 1:1, the AB bi-component liquid silicone rubber is solidified at room temperature after being evenly mixed in a rubber injection tube and then being injected into a mold prepared in the step S4.
  4. 4. The method for preparing the directional conductive silicone rubber sealing gasket of claim 3, wherein the AB bi-component liquid silicone rubber A component comprises a cross-linking agent, a catalyst, white carbon black and a reinforcing agent, and the B component comprises color paste, a flame retardant, a mildew preventive and a structure control agent.
  5. 5. The method for preparing the directional conductive silicone rubber sealing gasket of claim 3 wherein the AB two-component liquid silicone rubber A component comprises a foaming agent, a cross-linking agent, a catalyst, white carbon black and a reinforcing agent, and the B component comprises color paste, a flame retardant, a mildew preventive and a structure control agent.
  6. 6. The method of claim 4 wherein the AB two-component liquid silicone rubber casting product is a solid-core type oriented conductive silicone rubber gasket.
  7. 7. The method for preparing a directional conductive silicone rubber gasket as claimed in claim 5, wherein the AB two-component liquid silicone rubber casting product is a sponge directional conductive silicone rubber gasket.
  8. 8. The method for preparing the directional conductive silicon rubber sealing gasket according to claim 1, wherein the S5 is vulcanized for 24-48 hours at room temperature.

Description

Preparation method of directional conductive silicon rubber sealing gasket Technical Field The invention relates to the technical field of conductive rubber, in particular to a preparation method of a directional conductive silicon rubber sealing gasket. Background The conductive silicon rubber sealing gasket is a functional device with conductivity and environmental sealing property, is mainly prepared by taking silicon rubber as a matrix material, doping metal conductive filler and then molding or extruding and vulcanizing, is applied to a gap connecting part of electronic information equipment, and provides good electromagnetic protection and environmental sealing functions. The conductive sealing gasket prepared by filling silicon rubber with pure silver powder, graphite nickel-plated powder, silver-plated metal powder and the like serving as conductive fillers has been industrially applied, has volume resistivity of less than or equal to 0.01 ohm-cm, has the characteristics of high and low temperature resistance and corrosion resistance of the silicon rubber, and has been widely applied to the fields of aerospace, automobile industry, consumer electronics, military communication and the like requiring electromagnetic protection. The traditional conductive silicon rubber sealing gasket product adopts a single-phase structure, and the conductive rubber material filled with the metal filler is widely applied in high-end fields such as electronic communication, aerospace and the like due to excellent electrical performance (volume resistivity can reach 10 -2Ω·cm～10-3 ohm cm). However, in this type of gasket, the metallic filler therein is susceptible to oxidation reaction in air or a high temperature environment, so that the electrical properties of the gasket are lowered with the lapse of the service time. Meanwhile, the conductive network formed by mutually overlapping conductive particles has discontinuous points, so that the conductivity of the conductive network is difficult to reach the metal level. And the isotropic conductive performance is difficult to meet the application of occasions requiring unidirectional conduction. In addition, due to the addition of a large amount of conductive filler (the content of the conductive filler is generally 60-90 wt%), the filled conductive rubber has the defects of low strength, high density, high hardness, high cost and the like. The patent CN 103980711A and the patent CN 110894359A adopt a metal wire directional implantation process technology and a liquid silicone rubber casting molding process to prepare a rubber composite material with a directional conductive function, the anisotropic conductive function is realized, meanwhile, the corrosion resistance of the material is improved (compared with the traditional metal filling type conductive rubber, the content of metal wires in the directional conductive rubber is greatly reduced, each metal wire is mutually isolated, in a salt spray corrosion environment, electrolyte is difficult to permeate into a rubber matrix, so that the corrosion rate of the metal wires is greatly delayed, and according to experimental comparison, corrosion points exist on the surface of the metal filling type conductive rubber after a salt spray test, and the appearance of the directional metal wire conductive rubber is not obviously changed). In the two patents, the surface coupling treatment is carried out on the metal wire by adopting the silane coupling agent or the phthalate coupling agent to improve the bonding force between the metal wire and the silicon rubber, although the method can play a certain role in enhancing, the method still has the phenomena of breakage and fracture in the processes of high overload, strong impact and long-term use, the electromagnetic protection performance and the environmental sealing performance of the product are influenced, so that the application requirements are difficult to meet, and on the other hand, the poor bonding force between the metal wire and the silicon rubber leads to the phenomenon of easy wire stripping during cutting, the conductivity of the rubber sealing gasket is reduced, and the electromagnetic interference protection performance and the environmental sealing performance of equipment are adversely affected. Disclosure of Invention The invention aims at solving at least one of the technical problems existing in the prior art, and therefore, one aspect of the invention aims at providing a preparation method of an oriented conductive silicon rubber sealing gasket, which comprises the following specific steps: s1, arranging wires, namely equidistantly fixing wavy metal wires on a frame; S2, etching treatment, namely placing the wire frames arranged in the S1 into an oscillator containing an acid solution, taking out and cleaning the wire frames after the oscillation is finished, and taking out and airing the wire frames after the cleaning is finished; s3, adhesive treatment,