JP4095339B2 - Buffer material for relay switch - Google Patents

Description

【００３８】
【表２】

【００３９】
【発明の効果】
上記のとおり、この発明に係るリレースイッチ用緩衝材は、打抜き等で所望の形状に切断し、リレースイッチの可動接触子または固定部に緩衝材として取付けて絶縁や固着防止の目的で使用することができ、その際の打抜きや組込みの作業性が良好である。そして、耐熱性に優れているので、自動車のエンジンルームのような高温の雰囲気で使用された場合の耐久性や信頼性が高くなる。しかも、フッ素ゴムシートを未架橋の状態で基材フィルムに重ね、次いで上記のフッ素ゴムシートに架橋処理を施すことにより、容易に製造することができる。そして、請求項２に係る発明は、基材フィルムに対するフッ素ゴムシートの耐剥離性が特に優れており、請求項３に係る発明は、特に耐熱性に対する信頼性が向上する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a relay switch cushioning material, and provides a sheet-like relay switch cushioning material that has excellent durability and reliability when used at high temperatures, and has good punching workability and built-in workability. is there.
[0002]
[Prior art]
A buffer material is attached to the movable contact or the fixed portion for the purpose of insulating and preventing the fixed portion from the fulcrum portion and the fixed portion of the movable contact of the relay switch. As this cushioning material, a sheet of plastic or rubber is generally used. However, the plastic sheet is excellent in workability at the time of punching and assembling, but has a low buffering property and inferior anti-sticking property. On the other hand, the rubber sheet has excellent buffering properties and anti-adhesion properties, but has low heat resistance and insulating properties, and is inferior in workability during punching and assembling, and is not economical.
[0003]
[Problems to be solved by the invention]
This invention has good heat resistance, insulation and anti-sticking properties, particularly high durability and reliability when used at high temperatures, good workability during punching and assembly, and economically. An excellent sheet-like shock absorber for a relay switch is provided.
[0004]
[Means for Solving the Problems]
The buffer material for a relay switch according to the present invention is composed of a composite of a fluororubber sheet and a base film, and the base film is composed of a plastic film having a glass transition point of 70 ° C. or higher. The sheet is directly integrated without using an adhesive.
[0005]
The above relay switch cushioning material is composed of a composite of a rubber sheet and a base film (plastic film), so it is cut into a desired shape by punching or the like, and the cushioning material is placed on the movable contact or fixed part of the relay switch. And can be used for the purpose of insulation and prevention of sticking, and the workability of punching and assembly at that time is good. And since the rubber sheet is made of fluoro rubber, the base film is made of a plastic film having a glass transition point of 70 ° C. or more, and both are directly integrated without using an adhesive, it has excellent heat resistance. Durability and reliability when used in a high temperature atmosphere such as the engine room. However, heat resistance becomes inadequate that the glass transition point of a base film is less than 70 degreeC.
[0006]
The relay switch cushioning material is, for example, a method in which a fluororubber sheet is stacked on a base film in an uncrosslinked state, and then the fluororubber sheet is subjected to a crosslinking treatment. It can be manufactured by cross-linking and bonding the material sheet.
[0007]
The fluororubber used in the present invention is not particularly limited as long as it is a fluororubber, and examples thereof include vinylidene fluoride, tetrafluoroethylene / propylene, tetrafluoroethylene / perfluoromethyl vinyl ether, and the like. The rubbers described above include various heat resistance improvers, reinforcing fillers, pigments, anti-aging agents, antioxidants, mold release agents, flame retardants, thixotropy imparting agents, filler dispersants and adhesion improvers. A functional agent can be mix | blended suitably. Moreover, said fluororubber can also be used in mixture of 2 or more types, and another rubber can also be mix | blended in the range which can satisfy the below-mentioned characteristic.
[0008]
A crosslinking system is also optional, but a peroxide system is preferred. Moreover, the crosslinking method is also arbitrary, for example, thermal crosslinking may be used, and crosslinking using high-energy active rays such as electron beams and γ rays may be used. In particular, crosslinking by actinic radiation is preferable in that it is not necessary to add a peroxide crosslinking initiator, there is no deterioration in rubber properties due to these residues, and crosslinking can be performed efficiently and productivity is high. .
[0009]
The thickness of the fluororubber sheet is not particularly limited, but is preferably 0.01 to 2 mm, particularly preferably 0.05 to 1 mm. If the thickness is less than 0.01 mm, the buffering property is insufficient, and if it exceeds 2 mm, it is uneconomical.
[0010]
The plastic constituting the base film has a glass transition point of 70 ° C. or higher, and is polyphenylene sulfide, polycarbonate, polyimide, polyetherimide, polyesterimide, aramid, polyetheretherketone, polyethernitrile, polyether. Examples include engineering plastics such as sulfones and wholly aromatic polyesters.
[0011]
The thickness of the base film is not particularly limited. However, if the thickness is too thin, the composite becomes weak and easily broken, and the workability is deteriorated. Accordingly, the thickness is preferably 0.001 to 0.5 mm, particularly preferably 0.005 to 0.3 mm.
[0012]
In the relay switch cushioning material of the present invention, as described above, the fluororubber sheet and the base sheet are directly integrated without using an adhesive, but the interfacial adhesive force between the fluororubber sheet and the base sheet is high. When it is small, interfacial peeling is likely to occur during operation or use. Therefore, the above interfacial adhesive strength is preferably 10 N / 20 mm or more. The means for obtaining this interfacial adhesive force is arbitrary, but it is preferable that an adhesive property improver is blended in the composition constituting the fluororubber sheet and crosslinked as described above when the rubber is crosslinked.
[0013]
The above-mentioned adhesion improver is preferably a compound containing a reactive group active for radical reaction, and examples thereof include acrylic acid derivatives, methacrylic acid derivatives, and allyl derivatives, among which two or more unsaturated bonds, particularly A derivative having 3 or more is preferred. These compounds are widely used as rubber co-crosslinking agents, and examples thereof include acrylic acid esters and methacrylic acid esters of polyhydric alcohols, allyl esters of polycarboxylic acids, triallyl isocyanurate, triallyl cyanurate, and the like. .
[0014]
The polyhydric alcohol acrylic ester or methacrylic ester is an ester compound obtained by esterifying two or more alcoholic hydroxyl groups of a polyhydric alcohol having two or more alcoholic hydroxyl groups with acrylic acid or methacrylic acid. Glycol diacrylate, ethylene glycol dimethacrylate, 1,3 butanediol diacrylate, 1,3 butanediol dimethacrylate, 1,4 butanediol acrylate, 1,4 butanediol methacrylate, 1,6 hexanediol diacrylate, 1,6 Hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 2,2'bis (4-acryloxydiethoxyphenyl) propane, 2,2'bis (4-methacrylate) Roxydiethoxyphenyl) prone, glycerol dimethacrylate, glycerol triacrylate, glycerol trimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, Examples include pentaerythritol tetramethacrylate, tetramethylol methane diacrylate, tetramethylol methane dimethacrylate, tetramethylol methane triacrylate, tetramethylol methane trimethacrylate, tetramethylol tetraacrylate, tetramethylol tetramethacrylate, etc., especially 3 or more allyl acids Compounds containing ester or methacrylic acid ester.
[0015]
In addition, although said compound illustrated each single ester compound of acrylic acid and methacrylic acid, the form of mixed ester of acrylic acid and methacrylic acid may be sufficient. Examples of the allyl ester of polyvalent carboxylic acid include phthalic acid diarylate, trimellitic acid triarylate, and pyromellitic acid tetraarylate. And the adhesive improvement agent of the said rubber sheet may be used individually by 1 type, and may use 2 or more types together. Further, the adhesion improver used in the present invention is not limited to the above exemplary compounds.
[0016]
The compounding amount of the adhesion improver is 0.2 to 20 parts by weight, preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the total rubber component. On the contrary, when the amount exceeds 20 parts by weight, the effect of improving the adhesive strength reaches saturation and the physical properties of the rubber decrease.
[0017]
In order to improve the adhesion of the fluororubber sheet and the base film, the surface of the base film can be roughened by pretreatment with the active ray. Examples of the active ray treatment include radiation treatment such as electron beam and γ ray, ultraviolet treatment, corona discharge treatment, plasma treatment and flame treatment. Any one of these treatments may be performed alone, or a plurality of treatments may be used in combination. The treatment atmosphere is not particularly limited, but an inert gas or reducing gas atmosphere is preferred. A small amount of organic gas may coexist.
[0018]
In addition, by adhering an easy-adhesion layer made of a polyester polymer, polyurethane polymer, polyacrylic polymer or a mixture thereof on the surface of the base film in advance, the adhesion to the fluororubber sheet is further improved. be able to.
[0019]
As an adhesion improvement accelerator for promoting the adhesion improvement effect by the above adhesion improver, a peroxide can be blended with fluororubber, and by this blending, the delamination strength between the rubber sheet and the base sheet is increased. Is further improved. However, the compounding amount of the peroxide is preferably 0.05 to 10 parts by weight, particularly 0.1 to 5 parts by weight with respect to 100 parts by weight of the total rubber component, and if it is less than 0.05 parts by weight, the effect of improving adhesiveness is achieved. In the case where the expression of is not promoted and exceeds 10 parts by weight, the above-mentioned promoting effect is saturated and the physical properties of the rubber sheet are lowered.
[0020]
The peroxide may be either acyl-based or alkyl-based, such as benzoyl peroxide, monochlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl- 2,5 di (t-butylperoxy) hexane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-bis-t-butylperoxy-3,3 Examples include 5-trimethylcyclohexane, di-t-butyl peroxide, t-butylcumyl peroxide and the like. In addition, when the above-described peroxide is crosslinked by a heating method, it has an action of initiating a crosslinking reaction, and therefore it is necessary to blend it as a rubber component.
[0021]
The method of blending the above-mentioned compounding agent with rubber is arbitrary, and for example, when preparing a rubber compound, it may be carried out using a rubber kneader such as a two-roll, Banbury mixer, dough mixer (kneader), etc. In the case of dissolving in a rubber solvent and forming a film by a casting method, the rubber compound can be added and blended either when the rubber compound is dissolved in a solvent to make a solution or after the solution is made.
[0022]
The means for laminating the rubber sheet on the base film is also optional. For example, a rubber solution obtained by dissolving a rubber composition in a solvent is coated on the surface of the base film and dried to form a rubber thin film, rubber composition Examples thereof include a method of extruding an object on the surface of a base film under high pressure to form a rubber thin film, a calendar method, and the like. Moreover, when liquid fluororubber is used, it can coat without diluting with a solvent.
[0023]
Further, the surface roughness of the fluororubber sheet can be arbitrarily set as desired. As a method for controlling the surface roughness, a method of press-contacting a stamping roll on an uncrosslinked rubber sheet surface, or an uncrosslinked Examples thereof include a method of overlaying a cover sheet made of a film having different surface roughness on the rubber sheet surface.
[0024]
In this invention, since the above cover sheet is finally peeled off, the interfacial peeling force between the cover sheet and the fluororubber sheet needs to be weaker than the interfacial adhesive force between the fluororubber sheet and the substrate film. . That is, it is necessary to make a difference in the adhesiveness between both surfaces of the fluororubber sheet. Among the above-mentioned crosslinking methods, a method using active rays is a preferable crosslinking method in that the adhesiveness can be made different by optimizing the irradiation method and irradiation conditions.
[0025]
In the present invention, the heat resistance of the relay switch cushioning material is preferably 45% or more, particularly preferably 50% or more, when expressed in terms of tensile strength retention when heat-treated at 180 ° C. for 192 hours. By providing the above-described tensile strength retention rate, for example, when used as a buffer sheet for a relay switch used in a high-temperature atmosphere such as an automobile engine room, the reliability of the relay switch is improved.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
For 100 parts by weight (hereinafter simply referred to as “part”) of the fluororubber composition (peroxide crosslinking type), a compound containing a reactive group that is active against radical reaction as an adhesion improver, such as an acrylic acid derivative, Among methacrylic acid derivatives and allylic acid derivatives, preferably those having 2 or more unsaturated bonds, particularly preferably 3 or more, 0.2 to 20 parts, preferably 0.5 to 10 parts, ethyl acetate and the like A fluororubber solution is prepared by dissolving in a solvent. A substrate film having a glass transition point of 70 ° C. or more and a thickness of 0.001 to 0.5 mm, preferably 0.005 to 0.3 mm is prepared.
[0027]
The above fluororubber solution is dried on the above base film and coated so as to have a thickness of 0.01 to 2 mm, preferably 0.005 to 1 mm, and a cover film (for example, polyethylene) is applied to the surface of the obtained fluororubber layer. A mat-processed surface of a terephthalate film which is mat-processed on one side is overlaid, and this three-layer laminate is subjected to a crosslinking treatment by electron beam irradiation. In this case, the base film side of the fluororubber layer is strongly cross-linked by means such as electron beam irradiation from the base film side, and the base film is cross-linked to the fluororubber layer, while the opposite cover film side is It is lightly crosslinked to facilitate peeling of the cover film, and the surface shape of the cover film is transferred to the rubber layer surface.
[0028]
The obtained three-layer laminated sheet consisting of a base film, a fluororubber sheet and a cover film is cut into a desired shape by punching, etc., and then the cover sheet is peeled off and attached to a desired relay switch as a buffer material. ,used. In addition, the adhesiveness with respect to a fluororubber layer can be improved by previously processing one side (lamination surface of a fluororubber layer) of the said base film with the said active ray. Moreover, the said adhesiveness can be improved by laminating | stacking the easily bonding layer which consists of said polyester-type polymer etc. on the single side | surface of the said base film.
[0029]
Embodiment 2
0.05 to 10 parts, preferably 0.1 to 5 parts, of a peroxide is added to and mixed with 100 parts of the fluororubber composition of Embodiment 1 above, and this is molded into a sheet shape with a calendar, and the above-mentioned group is added. It laminates | stacks on a material film, The heat-crosslinking process is performed at the temperature of 120-190 degreeC to the laminated sheet of the obtained 2 layer structure, Crosslinking of a fluororubber layer and bridge | crosslinking adhesion with respect to a base film are performed simultaneously. Furthermore, an aging treatment is performed at 100 to 200 ° C. as necessary. In this case as well, active ray treatment for improving the adhesion of the base film and lamination of the easy-adhesion layer can be performed in the same manner as described above.
[0030]
【Example】
Various shock-absorbing materials for relay switches were prototyped and their performance was tested and compared. This performance test was conducted as follows.
Delamination strength:
A knife was put at the interface between the base film and the fluororubber sheet, and force was applied to the part, or immersion was performed in toluene to cause interface peeling, and measurement was performed by a T-type peeling method according to JIS-K6854.
Heat-resistant:
The sample was placed in an oven at 180 ° C., treated at the same temperature for 192 hours, the tensile strength before and after heating was measured according to JIS-K6301, and the strength retention by heat treatment was determined.
[0031]
Example 1
6 parts of pentaerythritol tetraacrylate are added to 100 parts by weight (hereinafter simply referred to as “parts”) of a commercially available binary fluororubber composition (peroxide crosslinking type, hardness 70 degrees) composed of tetrafluoroethylene and polypropylene. It mix | blended and melt | dissolved in ethyl acetate and prepared the fluororubber solution. In addition, a polyetherimide film (thickness 0.05 mm) having a glass transition point of 215 ° C. was prepared as a base film, and a polyethylene terephthalate film matte processed (thickness 0.025 mm) was prepared as a cover film. .
[0032]
The base film is guided to a roll coater, and the fluororubber solution is applied onto the base film so that the thickness is 0.25 mm after drying. The cover film is matted on the surface of the fluororubber layer. The surfaces were overlapped and pressed with a pressure roller, and the resulting laminate was introduced into an electron beam irradiation apparatus and subjected to crosslinking treatment by electron beam irradiation.
[0033]
In the laminate of the obtained base film, fluororubber sheet and cover film, the delamination strength between the base film and the fluororubber sheet is 20 N / 20 mm, and the delamination strength between the fluororubber sheet and the cover film is 0.8 N. The cover film was easy to peel off. The laminated sheet composed of the base film and the fluororubber sheet has a high heat resistance of 95%, and has high practicality as a buffer material for a relay switch used in a high-temperature part, for example, around an automobile engine. It was.
[0034]
Comparative Example 1
In Example 1 above, the substrate film was changed to a polyethylene terephthalate film (thickness 0.05 mm) having a glass transition point of 69 ° C., and compared with Example 1 except that easy adhesion treatment was performed on one side. The laminated sheet of Example 1 was obtained. In Comparative Example 1, the adhesion between the base film and the fluororubber sheet and the peelability between the fluororubber sheet and the cover film were the same as in Example 1, but the heat resistance was as low as 39%. As a buffer material for a relay switch used in a high temperature part, the practicality was inferior.
[0035]
Example 2
In Example 1 described above, the amount of pentaerythritol tetraacrylate was 2 parts, and 2 parts of 2,5-dimethyl-2,5di (t-butylperoxy) hexane was blended, and the resulting fluororubber composition The product was laminated on the substrate film of Example 1 by a calendering method so that the rubber thickness was 0.5 mm, and the obtained laminate was crosslinked at 170 ° C., followed by aging treatment at 150 ° C. In the obtained laminated sheet, the delamination strength between the base film and the fluororubber sheet was 18 N / 20 mm. Further, the heat resistance was 90%, which was suitable as a buffer material for a relay switch used at a high temperature as in Example 1.
[0036]
Examples 3-10
In Example 1, the laminated sheets of Examples 3 to 10 were obtained in the same manner as in Example 1 except that the film of Table 1 below was used instead of the polyetherimide film as the base film. The characteristics are as shown in Table 2 and are excellent in delamination strength and heat resistance as in Example 1, and were suitable as a buffer material for relay switches used at high temperatures.
[0037]
[Table 1]

[0038]
[Table 2]

[0039]
【The invention's effect】
As described above, the buffer material for a relay switch according to the present invention is cut into a desired shape by punching or the like, and is attached to the movable contact or fixed part of the relay switch as a buffer material and used for the purpose of insulation or prevention of sticking. The workability of punching and assembly at that time is good. And since it is excellent in heat resistance, durability and reliability when used in a high-temperature atmosphere such as an engine room of an automobile are increased. In addition, the fluororubber sheet can be easily produced by stacking the fluororubber sheet on the base film in an uncrosslinked state and then subjecting the fluororubber sheet to a crosslinking treatment. And the invention which concerns on Claim 2 is especially excellent in the peeling resistance of the fluoro rubber sheet with respect to a base film, and the invention which concerns on Claim 3 improves especially the reliability with respect to heat resistance.

Claims (6)

A buffer material for a relay switch having a tensile strength retention rate of 45% or more when heat-treated at 180 ° C. for 192 hours, comprising a composite of a fluororubber sheet and a base film, the base film having a glass transition point It consists of a plastic film of 70 ° C. or higher, and an unvulcanized fluororubber sheet is laminated on the plastic film, and the unvulcanized fluororubber sheet is cross-linked so that the fluororubber sheet is bonded to the base film. The fluororubber sheet is a fluororubber sheet containing tetrafluoroethylene and propylene units, and the plastic film is made of polyetherimide, polyimide, aromatic polyamide, wholly aromatic polyester, Polyether ether ketone, polysulfone, polyphenylene resin Fido, polyethersulfone, or cushioning material for relay switch, which is a polyethylene naphthalate. The buffer material for a relay switch according to claim 1, wherein the interfacial adhesive force of the fluororubber sheet and the base film measured by a T-type peeling method according to JIS-K6854 is 10 N / 20 mm or more. The relay switch cushioning material according to claim 1, wherein the crosslinking of the unvulcanized fluororubber sheet is performed by electron beam irradiation from the plastic film side. 2. The shock absorber for a relay switch according to claim 1, wherein the unvulcanized fluoro rubber sheet is crosslinked by thermal crosslinking. The relay switch cushioning material according to claim 1, wherein the fluororubber sheet has a thickness of 0.01 to 2 mm, and the plastic film has a thickness of 0.001 to 0.5 mm. 2. The buffer material for a relay switch according to claim 1, wherein the unvulcanized fluororubber sheet contains a co-crosslinking agent as an adhesion improver in fluororubber.