Fluororubber adhesive composition

Abstract

To provide a fluororubber pressure-sensitive adhesive composition excellent in adhesion and tackiness without detriment to the heat resistance, chemical resistance, weatherability, flame retardancy, etc., inherent in fluororubber.SOLUTION: A fluororubber adhesive composition comprising a modified fluororubber containing unsaturated bonds or unsaturated bonds and functional groups and having a Mooney viscosity ML1 + 10 (121 °C) of 10 to 80, and an acrylic copolymer-containing acrylic adhesive having a glass-transition temperature Tg of 20 °C or lower. The acrylic adhesive is used at a ratio of 10 to 400 parts by weight with respect to 100 parts by weight of the modified fluororubber.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fluororubber pressure-sensitive adhesive composition. It has excellent adhesiveness and stickiness without compromising the inherent heat resistance, chemical resistance, weather resistance, and flame retardancy of fluororubber. The present invention relates to a fluororubber pressure-sensitive adhesive composition.

[0002] Conventionally, adhesives have generally been vinyl acetate resins, ethylene vinyl acetate, copolymerization Resin, vinyl chloride resin, epoxy resin, urethane resin, styrene Resin-based adhesives such as resin, acrylic resin, polyamide resin, cyanoacrylate, cellulose resin, silane-based, and silicone-based adhesives ,or Rubber adhesives such as nitrile rubber, styrene-butadiene rubber, and chloroprene rubber are used. It is used. Heat-resistant adhesives are generally teeth There are acrylic adhesives and silicone adhesives, but acrylic adhesives have lower heat resistance than silicone adhesives, and silicone adhesives have lower adhesive strength than acrylic adhesives. adhesive Although it is difficult to use for long-term heat resistance above 175°C, silicone-based adhesive cannot be used for electronic parts due to its contamination.

[0003] Fluorine resins or fluororubbers have excellent heat resistance, and are excellent in long-term durability at temperatures above 175°C, chemical resistance, weather resistance, friction and abrasion resistance, etc., but they generally cannot be used alone as pressure-sensitive adhesives or adhesives because they have poor tackiness and adhesiveness. Fluorine rubbers, when not crosslinked, exhibit slight tackiness but have poor adhesiveness. Such uncrosslinked fluororubbers can exhibit tackiness and adhesiveness by dehydrofluorinating them with alkali, but because they are not crosslinked, they lack strength, solvent resistance, chemical resistance, and other liquid resistance, pressure resistance, etc. under heating The adhesive strength is poor, so the range of use is limited.

[0004] In addition, general fluororubbers are cross-linked with polyols, polyamines, peroxides, etc., to provide strength, resistance to liquids such as solvents and chemicals, pressure resistance, under heating Although the glass transition temperature (Tg) is below room temperature, the adhesive strength after crosslinking is teeth Crosslinked fluororubber generally cannot be used as an adhesive because it would result in poor tackiness and adhesiveness.

[0005] In addition, fluorine rubber Bisphenol AF etc. In polyol crosslinking using ethylenediamine or amine crosslinking using bifunctional polyamine compounds, dehydrofluorination occurs without a divalent metal oxide such as magnesium oxide or calcium hydroxide, resulting in the formation of carbon-carbon unsaturated bonds. Therefore, while a divalent metal oxide such as magnesium oxide or calcium hydroxide is essential for crosslinking, the divalent metal oxides absorb moisture, resulting in a rapid curing rate and the inability to store them in sheet form for long periods of time. Furthermore, calcium hydroxide cures quickly, and when dissolved in an organic solvent to form an adhesive, it gels quickly and cannot be used. Furthermore, adding large amounts of inorganic substances such as calcium hydroxide or magnesium oxide results in a loss of adhesiveness, further reducing the adhesiveness after crosslinking.

[0006] Furthermore, peroxide crosslinking of fluororubber requires crosslinking in a manner that blocks oxygen, such as by pressing, and exposed areas and areas through which oxygen can pass do not crosslink, which creates the problem of poor adhesion and liquid resistance in the uncrosslinked areas. In production, Blocking out air (oxygen) Short time Since crosslinking is performed by the use of a rubber composition, the crosslinking must be carried out quickly. If the adhesive is prepared by dissolving the rubber composition in an organic solvent, the rapid gelation makes it difficult to use, and the peroxide compound is deactivated by exposure to air during the drying of the solvent, making it impossible to achieve sufficient crosslinking.

[0007] Although general fluororubber can be crosslinked with a crosslinking agent such as an acid acceptor, it cannot be crosslinked with epoxy resin, which has excellent heat resistance and water resistance and can increase adhesive strength. Even if epoxy resin and polyamine are added to general fluororubber, the crosslink density of the fluororubber does not increase, although the epoxy resin reacts with the polyamine, and improvement in adhesiveness and liquid resistance cannot be achieved.

[0008] Patent Document 1 discloses a pressure-sensitive adhesive composition containing a fluorine-based oligomer having a weight-average molecular weight Mw of 3500 or more, an ionic compound, and an acrylic polymer. In this document, the inclusion of the acrylic polymer improves adhesiveness, but the fluorine-based oligomer does not have the same properties as other compounds such as the acrylic polymer. of Because of poor compatibility with polymers, the fluorine-based oligomer migrates to the surface after coating or drying, resulting in problems such as reduced surface tackiness and adhesiveness. The state of migration of the fluorine-based oligomer to the surface varies depending on the standing time and environmental temperature, and the adhesiveness does not stabilize. Furthermore, if it is crosslinked, the adhesiveness will be further reduced.

[0009] Patent Document 2 proposes a pressure-sensitive adhesive whose main component is a fluorocopolymer obtained by copolymerizing a (meth)acrylic acid perfluoroalkyl ester monomer, a (meth)acrylic acid alkyl ester monomer, a hydroxyl group-containing acrylic monomer, and a carboxyl group-containing acrylic monomer. However, the adhesive is not particularly high in adhesiveness, and the adhesive strength is low, and the adhesive deteriorates after being exposed to high temperatures for a long period of time, resulting in problems of reduced adhesiveness. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 7,177,581 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-292529 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-108287 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-105268 [Patent Document 5] Patent No. 3,327,447 [Patent Document 6] Patent No. 3,975,249 [Patent Document 7] Japanese Patent Application Laid-Open No. 2002-030263 [Patent Document 8] Japanese Patent Publication No. 59-059764 [Patent Document 9] Japanese Patent Application Publication No. 2-245046 Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention is to utilize the inherent heat resistance, chemical resistance, weather resistance, and flame retardancy of fluororubber. etc. The present invention aims to provide a fluororubber pressure-sensitive adhesive composition having excellent adhesiveness and tackiness without impairing the properties. [Means for solving the problem]

[0012] The object of the present invention is to provide a polymer having an unsaturated bond or a combination of an unsaturated bond and a functional group such as a carboxyl group. and Mooney viscosity ML 1+10 This is achieved by a fluororubber adhesive composition obtained by blending a modified fluororubber having a modulus of elasticity (Tg) of 10 to 80 with an acrylic adhesive containing an acrylic copolymer having a glass transition temperature Tg of 20°C or lower. [Effects of the Invention]

[0013] In the fluororubber adhesive composition of the present invention, an acrylic adhesive is blended with a modified fluororubber having unsaturated bonds (and functional groups such as carboxyl groups), and the modified fluororubber has excellent adhesion after long-term heating (heat resistance), chemical resistance, weather resistance, and flame retardancy. etc.This has the excellent effect of enabling the development of tackiness that is not as great as that of commercially available acrylic adhesives or silicone adhesives when used alone with fluororubber, without impairing the adhesive properties of the fluororubber itself. compound Copolymerized with No The adhesive strength can be adjusted by adding acrylic adhesive. Acrylic adhesive This is because the compatibility makes it possible to obtain an adhesive that has better heat resistance and adhesiveness than an acrylic adhesive alone.

[0014] Generally, when fluororubber is blended with acrylic rubber or acrylic adhesive and dissolved in a solvent, the solution will separate into layers, and even if it is coated, it will not dry. rear The coating surface is uneven, causing uneven thickness, and the adhesive tape or adhesive sheet etc. as Effectively enough However, by modifying fluororubber with alkali and blending it with an acrylic adhesive, layer separation of the solution can be prevented, eliminating unevenness on the coated surface, making it suitable for use as an adhesive tape or adhesive sheet. Effectively enough It can be used.

[0015] In this way, by using a modified fluororubber that has adhesiveness and bonding properties and is obtained by decomposing, lowering the molecular weight, and adding functional groups to uncrosslinked fluororubber with an inorganic or organic alkali, excellent effects are achieved, such as improved compatibility with acrylic pressure-sensitive adhesives, preventing separation even when mixed, and maintaining a good coating surface.

[0016] Such modified fluororubber can be used without adding an acid acceptor, which is commonly used. 、 By using a crosslinking agent that is commonly used in acrylic adhesives, the modified fluoro rubber and acrylic adhesive andThe adhesive can be co-crosslinked with other adhesives, resulting in higher tackiness and adhesiveness. Therefore, inorganic fillers such as acid acceptors are not necessarily required, and the addition of fillers does not deteriorate the tackiness, while the addition of a crosslinking agent can improve the tackiness. Furthermore, if an acid acceptor is not added, there is no hardening degradation due to the acid acceptor, and the adhesiveness does not decrease significantly with heating. Furthermore, even if other adhesives are added, they are compatible, and there is no layer separation, and the adhesive remains uniform even after coating and drying.

[0017] Until now, there has not been a pressure-sensitive adhesive that has better heat resistance than acrylic pressure-sensitive adhesives, higher adhesive strength than silicone pressure-sensitive adhesives, is free of silicone contamination, and is highly heat-resistant, but the fluororubber pressure-sensitive adhesive composition of the present invention can provide a pressure-sensitive adhesive that satisfies these requirements. Specifically, for example, when a steel ball with a diameter of 4.8 mm is placed on an adhesive surface formed on an inclined surface at an angle of 30 degrees, the adhesive has such adhesiveness that the steel ball does not roll off.

[0018] Such a fluororubber pressure-sensitive adhesive composition has a tackiness at room temperature. sex This allows lamination and bonding to the mating substrate at room temperature, and oven heating can further increase the adhesiveness and tackiness. In addition, because the fluororubber is modified to a low molecular weight, it can be embedded without gaps into the unevenness of the mating substrate, such as the unevenness of patterns on electronic circuit boards, resulting in high adhesive strength.

[0019] Polyamine crosslinking and polyol crosslinking of binary fluororubber are performed using divalent metal oxides such as magnesium oxide, calcium hydroxide, hydrotalcite, etc. Acid acceptorCrosslinking will not occur without these particles, but because these particles are large in size, adhesives containing these particles may have particles larger than the coating thickness, resulting in reduced tackiness, adhesion, and heat resistance. Furthermore, the particles tend to fall off from the adhesive surface, which can cause contamination in semiconductor applications, such as the falloff of inorganic filler particles. The fluororubber adhesive composition of the present invention allows the direct crosslinking reaction between the modified fluororubber and a crosslinking agent such as an epoxy resin, without the addition of divalent metal oxides such as magnesium oxide, calcium hydroxide, or hydrotalcite, thereby preventing contamination from particles on the adhesive surface.

[0020] Furthermore, even without using bisphenol AF, an environmentally hazardous substance, the modified fluororubber is crosslinked by the epoxy resin, and when the laminate is heated, there is little reactive gas and the laminate does not foam. DETAILED DESCRIPTION OF THE INVENTION

[0021] As the fluororubber, a highly fluorinated elastic copolymer, for example, an elastic copolymer of two or more kinds of vinylidene fluoride, hexafluoropropylene, pentafluoropropylene, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), etc., is used, preferably a vinylidene fluoride-hexafluoropropylene copolymer, particularly preferably a vinylidene fluoride-hexafluoropropylene copolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, or a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene-perfluoro(alkyl vinyl ether) quaternary copolymer.

[0022] In addition, Patent Document 3 proposes an adhesive composition comprising a non-peroxide-crosslinkable fluororubber polymer, a peroxide-crosslinkable fluororubber polymer, and a peroxide, but such an adhesive composition has a heat resistance sexAlthough it has excellent solvent resistance, it has no adhesiveness at room temperature, and the peroxide is deactivated by oxygen in the air, preventing a sufficient crosslinking reaction. Therefore, such an adhesive composition without an acrylic adhesive will stick to surfaces such as glass, but if a 4.8 mm diameter steel ball is placed on a 30 degree inclined surface, the steel ball will roll away.

[0023] Fluorine rubber is aqueous By emulsion polymerization or aqueous suspension polymerization As latex In the aqueous emulsion polymerization method, either a water-soluble peroxide alone or a redox system in which the peroxide is combined with a water-soluble reducing substance can be used as the reaction initiator system. Examples of water-soluble peroxides include ammonium persulfate, potassium persulfate, and sodium persulfate, and examples of water-soluble reducing substances include sodium sulfite and sodium hydrogen sulfite. In this case, a pH adjuster (a buffer) can be used as a stabilizer for the aqueous emulsion. opposition agents), such as sodium monohydrogen phosphate, sodium dihydrogen phosphate, potassium monohydrogen phosphate, potassium dihydrogen phosphate, etc. but It is used.

[0024] As an emulsifier used in emulsion polymerization, a fluorinated carboxylate is generally used, preferably CF3CF2CF2O [CF(CF3)CF2O] n CF(CF3)COONH4 (n: 1 or 2) is used. These emulsifiers are used in an amount of about 1 to 30 wt. % , preferably about 5 to 20 wt. % If the amount of emulsifier is less than this, the monomers and the resulting copolymer cannot be uniformly dispersed in the aqueous medium, and if it is too much, it is economically disadvantageous.

[0025] The copolymerization reaction is carried out at a temperature of about 20 to 80°C, preferably teeth The polymerization is carried out at a temperature of about 25 to 60° C. If the polymerization temperature is too high, problems such as foaming may occur during molding. The polymerization pressure is generally about 5 MPa or less.

[0026] Vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene are represented by the general formula emulsifier The copolymerization reaction is carried out in an aqueous medium in the presence of the following: The copolymerization reaction in an aqueous medium can also be carried out as a suspension polymerization method, but emulsion polymerization is preferred to obtain the desired average emulsion particle size. The emulsion polymerization reaction is carried out using a water-soluble inorganic peroxide such as ammonium persulfate or a redox system of such peroxide and a reducing agent as a catalyst, in the presence of a surfactant as an emulsifier, which is commonly used in an amount of about 0.001 to 0.2% by weight based on the total weight of the charged water, generally under conditions of a pressure of about 0 to 10 MPa, preferably about 0.5 to 4 MPa, and a temperature of about 0 to 100°C, preferably about 20 to 80°C. In this case, it is preferable to feed the fluorinated olefin mixture in portions so that the reaction pressure is maintained within a constant range. Furthermore, in order to adjust the pH in the polymerization system, Sodium monohydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate An electrolyte substance having a buffering capacity such as sodium hydroxide or the like may be added. Furthermore, a chain transfer agent such as ethyl malonate, acetone, isopropanol, etc. may be used as needed.

[0027] Although the polymerization reaction depends on various polymerization conditions, it is generally completed in about 1 to 15 hours, which is not much different from the case where ammonium perfluorooctanoate emulsifier is used. After the reaction is completed, an aqueous potassium alum solution, an aqueous sodium chloride solution, an aqueous calcium chloride solution, etc. is added to the obtained aqueous emulsion to coagulate the produced polymer, which is then washed with water and dried to obtain a fluorine-containing copolymer.

[0028] Here, fluorosurfactants are widely used as surfactants in emulsion polymerization reactions of fluorine-containing monomers. Among them, perfluorooctanoic acid CF 15 COOH or its salts [PFOA] isPFOA is known to be a surfactant with excellent monomer emulsification and latex stability. However, perfluorinated chemical substances are difficult to decompose in the natural environment, and it has recently been discovered that perfluorinated compounds with eight carbon atoms, such as PFOA, have a significantly long-lasting effect on the human body. In addition, due to PFOA's excellent affinity with rubber, after the coagulation of rubber latex obtained by emulsion polymerization, there is a high amount of PFOA adhering to and remaining in the resulting fluoroelastomer, and there is a strong demand for reducing this.

[0029] To meet such demands, it is considered that a means of imparting environmental degradability to a fluorine-containing emulsifier is to provide a hydrogenated portion in the perfluorinated hydrophobic group of the surfactant compound. In fluorine-containing rubber latex, perfluoroalkyl alkyl phosphonate C n F 2n+1 C m H 2m P(O)(OM 1 )(OM 2 ) as an emulsifier, it is possible to take measures against PFOA without using fluorine-based surfactants.

[0030] When a perfluoroalkyl alkyl phosphonate is used, perfluoroalkyl alkyl phosphonic acid C n F 2n+1 C m H 2m It can be obtained by reacting an alkali metal hydroxide or aqueous ammonia with P(O)(OH)2 (n: an integer of 2 to 6, m: an integer of 1 to 3). When an alkali metal hydroxide or ammonia is used in an equimolar amount relative to the perfluoroalkylalkylphosphonic acid, it forms a monosalt, and when used in a double molar amount, it forms a di-salt. Generally, it is used in an amount equal to or greater than the theoretically required number of moles, and when used in an equimolar amount but less than double the molar amount, a mixture of the mono-salt and the di-salt is formed.

[0031] Because these perfluoroalkyl alkyl phosphonates have a linear fluoroalkyl group, they have better solubility in water than fluoropolyether-type emulsifier compounds with equivalent emulsifying performance, and at the same time, they adhere less to the resulting fluoroelastomer than PFOA, so they can significantly reduce the amount of emulsifier remaining in the fluoroelastomer obtained by coagulating the fluoroelastomer latex obtained by emulsion polymerization using various methods such as salting out, acid precipitation, mechanical stirring, etc. The emulsion polymerization reaction of fluorine-containing monomers using this emulsifier is carried out in the same manner as when using a PFOA emulsifier.

[0032] The emulsion polymerization reaction is carried out using a water-soluble inorganic peroxide such as ammonium persulfate or a redox system of such a peroxide with a reducing agent as a catalyst, and to adjust the pH in the polymerization system, electrolytes with buffering capacity such as phosphates (NaHPO, NaHPO, KHPO, etc.) or borates (NaBO, etc.), or NaOH, etc., may be added. The emulsion polymerization reaction is carried out under pressurized conditions at about 30 to 120°C for about 1 to 48 hours using about 0.001 to 10% by weight, preferably about 0.01 to 5% by weight, of an emulsifier relative to water.

[0033] Furthermore, for the purpose of further enhancing adhesiveness, a modified fluororubber having a weight average molecular weight Mw of 300,000 or less is preferably used. The glass transition temperature Tg is preferably 20° C. or less. When a fluororubber within this range is used, adhesiveness is exhibited by modification, as described below, and the fluororubber can be dissolved in a solvent and applied.

[0034] Patent Document 4 describes an easy-to-use adhesive composition containing an acrylic resin, a hydroxyl group-containing resin such as a fluororesin, a wax, and a polyisocyanate compound, and Patent Document 5 describes an adhesive for vinylidene fluoride resins, which is composed of a soft fluororesin, an acrylic resin, a vinylidene fluoride resin, a polyisocyanate, and an organic solvent. but However, these compositions are adhesive during the crosslinking reaction, but since they lose adhesiveness after the crosslinking reaction, they can be used as coatings or adhesives, but cannot be used as pressure-sensitive adhesives.

[0035] The molecular weight, molecular weight distribution, and Mooney viscosity of fluororubber depend on the degree of polymerization, amount of alkali, denaturation temperature, time, etc. To adjust The weight average molecular weight Mw is measured by gel permeation chromatography and converted using a calibration curve prepared using standard polystyrene.

[0036] The fluororubber is used after being modified by a known modification method. or This is carried out by introducing unsaturated bonds through a partial dehydrofluorination reaction by base modification, such as alkali modification using an organic alkali, preferably an organic alkali (Patent Documents 6 to 7). By such modification treatment, HF is removed from the fluoropolymer main chain, and carbon-carbon unsaturated bonds are formed. A bond is formed The chain scission reaction reduces the molecular weight of the fluoropolymer, allowing it to be decomposed, decomposed into smaller molecules, and functionalized in a short time, resulting in a modified fluororubber with adhesive properties. warm Or even when heated 、 Since the organic alkali has little penetration into the rubber, it is preferable to use an organic alkali that penetrates into the fluororubber latex at room temperature. The organic alkali uniformly modifies the fluororubber, resulting in a more adhesive modified fluororubber.

[0037] Modified fluororubber has unsaturated bonds and functional groups such as carboxyl groups at the ends. have Therefore, by adding a crosslinking agent, the crosslinking agent reacts with the substrate to be bonded, forming a crosslink, improving adhesion, durability, liquid resistance, solvent resistance, and under heating The adhesive strength is improved, and it can be used as an adhesive that takes advantage of the characteristics of fluororubber.

[0038] In addition, partial dehydrofluorination forms unsaturated bonds in the main chain, and after the chain scission reaction, functional groups such as carboxyl groups are formed at the molecular chain ends by oxidation, allowing the formation of epoxy resins, diamine compounds, and polyamine compounds without the need for an acid acceptor. etc.The number of functional groups to be modified is not particularly limited.

[0039] The higher the denaturation temperature, the higher the molecular weight. thing The lower the value, the lower the molecular weight. thing When denaturing with inorganic alkali, the fluororubber must be heated to 40°C or higher for denaturation to occur. 、 Denaturation temperature is 40°C or higher So Since it becomes difficult to control the molecular weight, the denaturation is carried out at about 5 to 35°C. In the case of organic alkali, if the denaturation temperature is lower than room temperature, it takes time for the denaturation to stabilize. Hanging At room temperature, between 20 and 30°C, denaturation can be achieved stably in a short time. If the denaturation time is short, the denatured state will vary widely, but if it is long, the denaturation will be less varied. If there is a lot of denaturant, the low molecular weight thing The amount of denaturant is increased depending on the required molecular weight. is adjusted Heat drying temperature after denaturing cleaning teeth The temperature is about 60 to 150°C, preferably about 80 to 120°C. If the temperature is lower than this, insufficient drying and residual solvent may cause foaming and low molecular weight compounds during lamination of the adhesive sheets. thing If the residual amount is higher than this, cross-linking increases, the resin becomes polymerized, and the adhesiveness decreases.

[0040] Organic alkalis include 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), tetramethylammonium hydroxide, tetramethylammonium hydroxide, and tetrabutylphosphonium hydroxide. etc. At least one selected from the following is used: The inorganic alkali includes potassium hydroxide, sodium hydroxide, lithium hydroxide, etc., which are dissolved in water and mixed with the fluororubber.

[0041] The modified fluoro rubber conforms to JIS K6300-1 (2013) Mooney viscosity ML 1+10 (121°C) is 10 to 80, preferably 10 to 50, and the weight average molecular weight Mw is 1.0 × 10 5 ~3.0×105 , and the number average molecular weight Mn is 0.3 × 10 5 ~7.0×10 5 A Mooney viscosity within this range is used. If the Mooney viscosity is higher than this range, there is no adhesiveness, and if it is lower than this range, liquid substances will be contained due to decomposition during modification, which will cause staining on the adherend and will actually reduce adhesiveness. Here, the Mooney viscosity is measured in accordance with JIS K6300-1 (2013) using a Mooney Viscometer SMV-201 (manufactured by Shimadzu Corporation) at a temperature condition of 121°C. 、 The preheating time is 1 minute and the rotor rotation time is 10 minutes.

[0042] Fluorine rubber Mooney viscosity ML 1+10 The temperature (121°C) is lowered by 15 to 70, preferably 20 to 70, compared to before modification due to the decomposition of the fluororubber caused by modification. This allows adhesiveness to be developed.

[0043] The modified fluororubber latex liquid or solution is salted out. or After coagulation, washing with water removes the fluorine. rubber Components other than those listed above can be easily removed at low cost, and are suitable for electronic and semiconductor components. etc. Non-staining adhesive that can be used for Form This is because the fluororubber is prepolymerized (partially cross-linked) by heating and drying the water, which gives it adhesiveness.

[0044] The acrylic adhesive contains, in addition to acrylic acid monomers and methacrylic acid monomers, acrylic acid ester monomers and methacrylic acid ester monomers having highly crosslinkable functional groups. For example, at least one of a monomer not containing a functional group, such as ethyl acrylate (EA), butyl acrylate (BA), or methyl methacrylate (MMA), and a monomer containing a highly crosslinkable functional group, such as methacrylic acid (MAA) or monobutyl fumarate (MBF), is used. and Copolymerization using

[0045] The monomer not containing a functional group is specifically a (meth)acrylate (excluding ethyl methacrylate and methyl methacrylate) having an alkyl group, which is a component for easily adjusting the Tg of the entire adhesive layer to an appropriate range, such as ethyl acrylate. 、 Methyl acrylate, butyl (meth)acrylate 、 2-Ethylhexyl (meth)acrylate 、 Propyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, vinyl acetate 、 Examples include vinyl propionate, styrene, and (meth)acrylonitrile, and preferred are ethyl acrylate, butyl (meth)acrylate, and acrylonitrile. 、 Examples of suitable adhesives include at least one selected from the group consisting of methyl acrylate, 2-ethylhexyl (meth)acrylate, and vinyl acetate. By using these, it becomes easier to adjust the peel strength from the adherend and also easier to adjust the Tg of the entire adhesive layer to an appropriate range.

[0046] Examples of the monomer containing a highly crosslinkable functional group include a monomer having a carboxyl group, a hydroxyl group, an amino group, an acetoacetoxyethyl group, an epoxy group, etc., and preferably a monomer containing at least one group selected from a carboxyl group and a hydroxyl group from the viewpoint of versatility, and more preferably a monomer containing a carboxyl group. but Examples include:

[0047] Examples of the monomer containing a carboxyl group include unsaturated carboxylic acids such as (meth)acrylic acid (methacrylic acid and / or acrylic acid), fumaric acid, maleic acid, itaconic acid, crotonic acid, trimellitic acid, and pyromellitic acid; unsaturated dicarboxylic acid monoesters such as monomethyl itaconate, monobutyl itaconate, monobutyl fumarate, and 2-acryloyloxyethyl phthalate; 2-Examples include unsaturated tricarboxylic acid monoesters such as (meth)acryloyloxyethyl trimellitic acid and 2-(meth)acryloyloxyethylpyromellitic acid; and carboxyalkyl (meth)acrylates such as carboxyethyl (meth)acrylate and carboxypentyl (meth)acrylate.

[0048] These monomers are used in a ratio of 30 to 95.5% by weight of monomers without highly crosslinkable functional groups and 0.5 to 70% by weight of monomers with highly crosslinkable functional groups, Ethyl acrylate, etc. The more low molecular weight monomers there are, the better the compatibility with modified fluororubber tends to be. By copolymerizing a monomer with a highly crosslinkable functional group, the degree of crosslinking can be adjusted. 、 Increasing the degree of crosslinking increases adhesive strength and improves liquid resistance, but decreases tackiness, so the copolymerization ratio is adjusted depending on the application.

[0049] The synthesis of the acrylic copolymer is carried out by polymerizing these monomers in the presence of a polymerization initiator. The polymerization method is not particularly limited, and a conventionally known method can be used, for example. Solution polymerization method , emulsion polymerization law , suspension polymerization law , bulk polymerization Law etc. Among them, solution polymerization is preferred because it is easy to carry out polymerization. law When solution polymerization is used as the polymerization method, the reaction solvent is preferably, for example, acetic acid Ethyl, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, diethyl ether, etc. Use These reaction solvents may be used alone or in combination of two or more.

[0050] The polymerization initiator is not particularly limited, and radical polymerization initiators, anionic polymerization initiators, cationic polymerization initiators, etc. can be used. Among them, thermal radical polymerization initiators are preferably used. Examples of thermal radical polymerization initiators include organic peroxides and azo compounds. Examples of organic peroxides include 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, tert-hexylperoxypivalate, tert-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyisobutyrate, tert-butylperoxy-3,3,5-trimethylhexanoate, and tert-butylperoxylaurate. Examples of azo compounds include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.

[0051] Among the resulting acrylic copolymers, those having a Tg of 20° C. or less, preferably 0° C. or less, are used as acrylic adhesives. By using those having such a Tg, the adhesiveness at room temperature is improved.

[0052] The weight average molecular weight Mw of the acrylic copolymer is preferably about 100,000 to 1,000,000, more preferably about 300,000 to 500,000. The weight average molecular weight Mw varies depending on the polymerization conditions, such as the type or amount of the polymerization initiator, the polymerization temperature, and the monomer concentration. etc. If the temperature is lower than this range, the adhesive strength will be low and foaming will occur after lamination. If the temperature is higher than this range, the compatibility with the modified fluororubber will deteriorate, the liquid will separate into layers, and the surface will lose its adhesiveness.

[0053] The lower the weight-average molecular weight Mw of the acrylic copolymer, the better the adhesiveness, and if it exceeds 1,000,000, the adhesiveness will be lost even if the Tg is below 20°C. If it is an acrylic adhesive instead of an acrylic rubber, commercially available products can be used as they are, such as Toagosei's Arontack S-1511X, S-3403, S-3452YKF, Saiden Chemical's Saibinol AT-193, AT-D40, AT-D50, AT-D45, AT-191, AT-260NT, ATR-1, ATR-373, ATR-347, and DIC product CT-5030, Nippon Carbide Do Industrial products such as Nissetsu KP-2500 are used.

[0054] In addition, Patent Document 8 proposes a heat-sensitive adhesive made of a fluorine-containing thermoplastic rubber containing an acrylic polymer, etc., but such a heat-sensitive adhesive is an adhesive used in commercially available adhesive tapes. teeth Since the acrylic polymer is rubbery, it has almost no tackiness and can be used as a heat-sensitive adhesive, but it cannot be used as a pressure-sensitive adhesive that is pressed at room temperature. If a crosslinking agent is added to this adhesive and crosslinked before lamination, the adhesive loses its tackiness and adhesiveness, so it must be laminated to the bonding surface before crosslinking. 、 The desired adhesiveness cannot be obtained. Furthermore, Patent Document 9 discloses a rubber composition obtained by compounding an organic peroxide or the like with a blend rubber of a specific fluororubber and acrylic rubber. As with the invention described in Patent Document 8, the molded product obtained from the disclosed rubber composition is rubbery and does not have the adhesive properties used in commercially available adhesive tapes. teeth It has almost no tack at room temperature and cannot be used as a pressure-sensitive adhesive.

[0055] In both of these inventions, fluororubber is combined with a rubber-like acrylic polymer, The present invention However, the desired adhesiveness could not be achieved, and although it would stick to surfaces such as glass, if a rubber surface were formed on a slope at an angle of 30 degrees and a steel ball with a diameter of 4.8 mm were placed on it, the steel ball would roll away.

[0056] The acrylic adhesive is blended in a ratio of 10 to 400 parts by weight, preferably 25 to 250 parts by weight, per 100 parts by weight of the modified fluororubber. If the blending amount is less than this, the adhesiveness will decrease, while if it is more than this, the heat resistance and solvent resistance will deteriorate. The adhesiveness can be adjusted depending on the amount of acrylic adhesive. By blending the acrylic adhesive with the modified fluororubber, it is possible to adjust the desired adhesiveness and adhesion that cannot be obtained with the modified fluororubber alone.

[0057] The blending method generally involves dissolving the modified fluororubber in a solvent and then blending the solution-polymerized acrylic adhesive solution with the solvent by stirring. rubber After modifying the latex with alkali, mix with emulsion acrylic adhesive. Also A method of kneading a solvent-free acrylic adhesive with a solid modified fluororubber using a roll or kneader can be used.

[0058] By further adding a crosslinking agent to the fluororubber composition, a reaction between the terminal functional groups of the prepolymerized fluororubber and the crosslinking agent can be achieved. moreover The crosslinking agent reacts with the substrate to form a crosslink, providing durability, liquid resistance, and chemical resistance. etc. This will improve.

[0059] As a crosslinking agent 、The material is not particularly limited as long as it hardens upon heat treatment, and one or more of thermosetting resins such as epoxy resins, phenolic resins, xylene resins, guanamine resins, diallyl phthalate resins, vinyl ester resins, unsaturated polyester resins, furan resins, polyimide resins, polyurethane resins, cyanate resins, maleimide resins, benzocyclobutene resins, and butadiene resins, aromatic diamine compounds, and aliphatic diamine compounds can be used. Epoxy resins are preferred in terms of reactivity, heat resistance, and adhesion to substrates, and aromatic diamine compounds are preferred in terms of pot life. Epoxy resins and aromatic diamine compounds not only enhance adhesion to substrates, but are also capable of crosslinking with both modified fluororubber and acrylic adhesives, and therefore, in the cured product of the adhesive composition, they improve adhesion with modified fluororubber and acrylic adhesives, compatibility in coating solutions, and solvent resistance, chemical resistance, water resistance, and water vapor resistance of the sheet after coating and drying. etc. If a crosslinking agent such as epoxy resin is used, the crosslinking reaction will occur even in the presence of oxygen and air, so even if the crosslinking reaction does not occur by blocking air and oxygen with a press, crosslinking will occur by coating and oven drying, and the adhesive reaction can be carried out with the mating material.

[0060] Examples of epoxy resins include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, and bisphenol A novolac-type epoxy resins; alicyclic epoxy resins; aliphatic chain epoxy resins; diglycidyl ethers of biphenols, diglycidyl ethers of naphthalenediol, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and alkyl-substituted and hydrogenated versions thereof; cresol novolac-type epoxy resins are preferred. One type of epoxy resin may be used alone, or two or more types may be mixed together.

[0061] Examples of polyamine compounds that can be used include 4,4'-methylbis(2-ethyl-6-methylaniline), diaminodiphenylsulfone, diaminodiphenylmethane, m-phenylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, etc. From the viewpoints of adhesive liquid life, adhesive sheet life, and heat resistance, aromatic diamine compounds are preferred over aliphatic ones.

[0062] Crosslinking agent is used for 100 parts by weight of modified fluororubber. hand The thermosetting resin is used in a proportion of 1 to 50 parts by weight, preferably 4 to 20 parts by weight. By adding the thermosetting resin, the adhesiveness, adhesion to the substrate, solvent resistance, durability, etc. are improved. Less than The adhesive strength is low, and the liquid resistance and durability are reduced. If there are many The compatibility becomes poor, the adhesiveness is lost, and the material becomes hard.

[0063] As a curing catalyst for crosslinking, an imidazole compound such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzylimidazole, 1-benzyl-2-methylimidazole, 2,4-diamino-6-[2-methylimidazoline-(1)]-ethyl, s-triazine, etc. is used. The curing catalyst is used in an amount of 100 parts by weight of modified fluororubber. 0.1 ~5 parts by weight, preferably 0.2 If the blending ratio of the curing catalyst is less than this, the curing of the fluoro rubber will be slow and crosslinking will be reduced. Conversely, if the blending ratio of the curing catalyst is more than this, the curing speed of the fluoro rubber will increase and the crosslinking will be reduced. Adhesive The adhesive organic solvent solution may become unstable over time, the storage stability of the coated sheet may decrease, and adhesion may decrease due to increased crosslink density or residual catalyst. Depending on the type of epoxy resin and the adjustment of the curing speed, it may be possible to avoid the use of a catalyst by heat treatment.

[0064] To adjust the tackiness and adhesiveness of the fluororubber adhesive composition, a tackifier resin, a plasticizer, a liquid rubber, a liquid resin, a filler, etc. may be added or used in combination as appropriate, within the scope of not impairing the object of the present invention. Here, depending on the heating temperature and heating time after lamination to the counterpart material, the adhesive strength may increase and the adhesive may be transferred to the counterpart material. 、 To prevent such transfer 、 In some cases, the amount of crosslinking agent may be reduced, and plasticizers, liquid rubbers, liquid resins, etc. may be added or used in combination as appropriate.

[0065] Examples of tackifying resins include rosin ester tackifying resins with a hydroxyl value of less than 40 mgKOH / g, terpene resins, terpene phenol resins, coumarone-indene resins, alicyclic saturated hydrocarbon resins, C5 petroleum resins, C9 petroleum resins, and C 5~9 Copolymerized petroleum resins and the like are included.

[0066] Examples of the plasticizer include phthalate ester-based plasticizers, fatty acid dibasic acid ester-based plasticizers, trimellitate ester-based plasticizers, epoxy-based plasticizers, phosphate ester-based plasticizers, ether-based plasticizers, polyester-based plasticizers, and chlorine-based plasticizers.

[0067] Examples of liquid rubber include isoprene, 1,4-polybutadiene, NBR, and HNBR, each having a viscosity of 10 to 100,000 mPa·s.

[0068] Examples of liquid resins include terpene resins, epoxy resins, polyamide resins, acrylic resins, 1,2-polybutadiene, polyether polycarbonates, and polyethylene glycols, all of which have a viscosity of 10 to 100,000 mPa·s.

[0069] As the filler, known materials can be used, for example, Ba Aluminum hydroxide, magnesium hydroxide etc. Metal hydroxides, aluminum oxide, antimony oxide, tin oxide, titanium oxide, manganese oxide etc.Examples of fillers include inorganic fillers such as metal oxides, silica, calcium silicate, aluminum silicate, calcium carbonate, silicon nitride, aluminum nitride, boron nitride, talc, mica, and kaolin, reinforcing materials, and various organic and inorganic flame retardants. If the maximum particle size of the filler is larger than the adhesive coating thickness, unevenness will occur in the coated sheet, so the adhesiveness can be adjusted by the particle size and filler content. To increase adhesiveness, it is preferable to add less than 3% or no filler at all.

[0070] The solvent used in the fluororubber pressure-sensitive adhesive composition is not particularly limited as long as the organic solvent dissolves the fluororubber. For example, methyl ethyl ketone 、 Methyl isobutyl ketone, di-n-propyl ketone, diisobutyl ketone, phoron, isophorone , cyclohexanone, etc. ketone solvents, aromatic hydrocarbon solvents such as toluene and xylene, ester solvents such as ethyl acetate and butyl acetate, alcohol solvents such as ethanol, 2-propanol, n-butanol, amyl alcohol, and heptanol but These may be used as a mixed solvent of two or more kinds.

[0071] Examples of substrates to which the fluororubber pressure-sensitive adhesive composition can be applied include reinforcing films such as polyimide films, polyether ether ketone films, polyphenylene sulfide films, aramid films, polyethylene naphthalate films, liquid crystal polymer films, polyethylene terephthalate films, polyethylene films, polypropylene films, TPX films, and fluororesin films; copper, silver, gold, tin, aluminum, indium, and alloys thereof. etc. In some cases, the coating is applied to a metal, a release film, a peeling film, a release paper, or the like, and then the coating is transferred by being attached to a reinforcing film or metal.

[0072] The resin material constituting the base film may contain, as required, an antioxidant, an ultraviolet absorber, a plasticizer, a colorant such as a pigment or a dye. 、Various additives may be added, for example, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of a primer, etc. etc. Such surface treatments may be, for example, Ba This treatment can be carried out to improve the adhesion between the base film and the pressure-sensitive adhesive layer (anchoring properties of the pressure-sensitive adhesive layer). Base material The thickness of the film is usually 5 to 200 μm, preferably about 10 to 100 μm. When the thickness of the substrate film is within this range, the workability of laminating the film to an adherend and the workability of peeling the film from the adherend are excellent, which is preferable.

[0073] The adhesive application method may be, for example, of The concentration is adjusted to 10 to 50% by weight, preferably 15 to 40% by weight, and then coating is carried out so that the thickness after drying is 5 to 200 μm. Coating methods include roll coating, die coating, knife coating, and screen printing. 、 Partial application by a dispenser or inkjet is also possible. The viscosity of the coating liquid is adjusted to suit each coating method. For example, in roll coating, the viscosity is preferably 500 to 5,000 mPa·s, and the solid content concentration is adjusted appropriately depending on the air temperature and liquid temperature. For example, an organic solvent solution of the above-mentioned pressure-sensitive adhesive composition is prepared, and polyimide is added. etc. Applying this to the resin film layer to form the adhesive layer did After that, it is dried at about 50 to 200°C for about 1 to 15 minutes to obtain an adhesive film. thing If the resin contains , foaming may occur when heated after lamination. In such cases, the drying temperature after coating can be increased to about 200°C.

[0074] Lamination conforms to JIS Z 0237 2009, Test Methods for Adhesive Tapes and Sheets, and can be performed using a roller or roll laminator at room temperature or with heating. Furthermore, when using a vacuum press or heated press to process the material with heated air at approximately 150-200°C for approximately 10 seconds to 3 hours (oven crosslinking), adhesive strength can be further improved by post-processing at approximately 150-200°C for approximately 1 minute to 15 hours. After lamination, adhesive strength can also be increased by heating the material in an oven at approximately 80-200°C for approximately 1 minute to 24 hours, even without pressing. [Example]

[0075] Next, the present invention will be described with reference to examples.

[0076] Reference example 1 [Preparation of Fluorine Rubber Latex Liquid] A 30 L stainless steel pressure vessel equipped with a stirrer was charged with 15 kg of water and 2.5 g of emulsifier (Neos product FS-1110), and the internal space was then thoroughly purged with nitrogen gas. Then, 1,285 g of vinylidene fluoride [VdF] and 1,831 g of hexafluoropropene [HFP] were introduced, and the temperature inside the reactor was raised to 70°C. The pressure inside the reactor when it reached 70°C was 3.09 MPa.

[0077] The VdF / HFP mixed gas with the same weight ratio as that used at the time of charging was used as the initial charging gas, and the internal pressure was 24 kgf / cm 2 The autoclave was pressurized until the internal pressure reached 2.94 MPa. Thereafter, 10 g of diethyl malonate was pressurized, and the internal temperature was raised to 80°C. An aqueous polymerization initiator solution prepared by dissolving 5 g of ammonium persulfate in 150 g of water was pressurized into the autoclave to initiate the polymerization reaction. When the internal pressure dropped to 2.842 MPa, the same VdF / HFP mixed gas was pressurized until the internal pressure reached 2.94 MPa. Every time the internal pressure dropped to 2.842 MPa, the VdF / HFP mixed gas was pressurized until the internal pressure reached 2.94 MPa. This operation was repeated. Three hours after the first addition of the mixed gas after the start of the polymerization reaction, 、After the addition of the VdF / HFP mixed gas of the same composition was completed, the unreacted gas in the autoclave was immediately purged to stop the reaction, yielding 23 kg of an aqueous emulsion (fluororubber latex liquid) (solids concentration 32%, solid fluororubber 7,310 g).

[0078] [Fluororubber Modification] While stirring 1 kg of fluororubber latex liquid at a liquid temperature of 25°C, 40 g of 10 wt % sodium laurate aqueous solution at a liquid temperature of 25°C was added dropwise. 、 119.2 g of an aqueous DBU solution containing 19.2 g of DBU was added, and the mixture was further stirred at room temperature at 100 rpm for 5 hours to modify the fluororubber.

[0079] [Salting out of fluororubber] The modified fluororubber latex liquid was added dropwise to 3 kg of 20 wt % NaCl aqueous solution stirred at 400 rpm and finely dispersed by stirring for 5 minutes. Five liters of water was added, and after stirring for 5 minutes, the mixture was left to stand for 3 minutes to allow the fluororubber to settle. The upper layer was removed, and the fluororubber-modified latex liquid was salted out.

[0080] [Washing Fluororubber with Water] Five liters of water was added, the mixture was stirred at 400 rpm for five minutes, and then allowed to stand for two minutes. The modified fluororubber was washed with water, allowed to settle, and the upper layer was removed; this process was repeated five times, after which five liters of water was added, the mixture was stirred at 400 rpm for 30 minutes, and similarly allowed to stand for two minutes. The modified fluororubber was washed with water, allowed to settle, and the upper layer was removed; this process was repeated five times.

[0081] [Drying Fluororubber] The resulting washed modified fluororubber was placed on a net at a height of 30 mm or less and dried in an oven at 80°C for 15 hours. The Mooney viscosity ML of the dried modified fluororubber was 1+10 (121℃) is 10, weight average molecular weight Mw teeth It was 200,000 yen.

[0082] Reference example 2 In Reference Example 1, the fluororubber was not modified. Mooney viscosity ML of unmodified fluororubber after drying 1+10 (121°C) was 50, and the weight average molecular weight Mw was 500,000.

[0083] Reference example 3 900 g of methyl isobutyl ketone was added to 100 g of the dried unmodified fluororubber obtained in Reference Example 2, and 100 g of a 20 wt % potassium hydroxide solution was added, followed by stirring at 60°C, 100 rpm, and 8 hours. did Then, 9% by weight of sulfuric acid was added dropwise until the pH reached 3, and the fluororubber was modified. The modified fluororubber solution was added dropwise to ethanol while stirring, and then the mixture was stirred. 1 The Mooney viscosity of the fluororubber after drying was ML 1+10 (121°C) was 30, and the weight average molecular weight Mw was 300,000.

[0084] Reference example 4 [Preparation of acrylic adhesive solution] In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 49 parts by weight of ethyl acrylate, 49 parts by weight of butyl acrylate, 1 part by weight of monobutyl fumarate, and 150 parts by weight of ethyl acetate were charged, and the mixture was stirred at 150 rpm while being purged with nitrogen gas for 30 minutes. did Then, 0.2 parts by weight of 2,2'-azobisisobutyronitrile was added as a polymerization initiator, and the liquid temperature was maintained at around 65°C to carry out a polymerization reaction for 6 hours. Solid concentration A 40% by weight acrylic adhesive solution was prepared. The weight average molecular weight Mw was 220,000 and the Tg was -43°C.

[0085] Reference example 5 In Reference Example 4, butyl acrylate instead of The amount of ethyl acrylate was changed to 99 parts by weight. Used, solids concentration A 40% by weight acrylic adhesive solution was prepared. The weight average molecular weight Mw was 110,000 and the Tg was -18°C.

[0086] Example 1 100 parts by weight of the modified fluororubber obtained in Reference Example 1 Acrylic adhesive solution obtained in Reference Example 4 250 (equivalent to 100 parts by weight in terms of solid content) o-Cresol novolac epoxy resin (DIC product N-695) 8 〃 Imidazole curing catalyst (Shikoku Kasei product Curesol 2E4MZ) 0.5 〃 Butyl acetate 684 〃 The above components were dissolved to obtain a fluororubber composition.

[0087] Example 2 In Example 1, the amount of the acrylic adhesive solution was changed to 125 parts by weight (equivalent to 50 parts by weight in terms of solid content), and the amount of butyl acetate was changed to 559 parts by weight.

[0088] Example 3 In Example 1, the amount of the acrylic adhesive solution was changed to 1000 parts by weight (equivalent to 400 parts by weight in terms of solid content), and the amount of butyl acetate was changed to 1430 parts by weight.

[0089] Example 4 In Example 1, the same amount (100 parts by weight) of the modified fluororubber obtained in Reference Example 3 was used as the fluororubber.

[0090] Example 5 In Example 1, the same amount (250 parts by weight, equivalent to 100 parts by weight of solid content) of the acrylic adhesive solution obtained in Reference Example 5 was used as the acrylic adhesive solution, and the amount of butyl acetate was 684 parts by weight. 、 Each was modified and used.

[0091] Example 6 In Example 1, 1.4 parts by weight of 4,4'-methylenebis(2-ethyl-6-methylaniline) (Curehard MED-J, a product of Kumiai Chemical Industry Co., Ltd.) was further used, and the amount of butyl acetate was changed to 690 parts by weight.

[0092] Example 7 In Example 2, the o-cresol novolac epoxy resin and the imidazole curing catalyst were not used, and the amount of butyl acetate was changed to 750 parts by weight.

[0093] Example 8 In Example 1, the amount of acrylic adhesive solution was changed to 500 parts by weight (equivalent to 200 parts by weight of solid content), the amount of o-cresol novolac epoxy resin was changed to 20 parts by weight, and the amount of butyl acetate was changed to 982 parts by weight.

[0094] Comparative Example 1 In Example 1, the modified fluororubber was not used, and the amount of butyl acetate was changed to 552 parts by weight.

[0095] Comparative Example 2 In Example 1, the same amount (250 parts by weight; 100 parts by weight in terms of solid content) of the unmodified fluororubber obtained in Reference Example 1 was used in place of the modified fluororubber.

[0096] Comparative Example 3 100 parts by weight of unmodified fluororubber obtained in Reference Example 2 Calcium hydroxide (Omi Chemical Industry Products Caldic♯1000) 3 〃 Magnesium oxide (Kyowa Chemical Industry Products MgO♯30) 6 〃 Vulcanizing agent (DuPont Curative #30) 6 Crosslinking accelerator (Hokko Chemical Industry Products BTPPC; 0.4 〃 benzyltriphenylphosphonium chloride) Butyl acetate 461 〃 The above components were dissolved to obtain a fluororubber composition.

[0097] Comparative Example 4 In Example 1, the same amount (100 parts by weight) of acrylic rubber (Unimatec product PA522HF) was used instead of the acrylic adhesive solution, and the amount of butyl acetate was changed to 834 parts by weight.

[0098] Comparative Example 5 In Example 1, the acrylic adhesive solution was not used, and the amount of butyl acetate was changed to 434 parts by weight.

[0099] The fluororubber compositions obtained in the above Examples and Comparative Examples were used as adhesives to conduct adhesive solution solubility tests, curing tests, solvent resistance tests, adhesion evaluations, initial adhesion evaluations, and adhesion tests after heat resistance tests. For the solvent resistance tests, adhesion evaluations, initial adhesion evaluations, and adhesion tests after heat resistance tests, the fluororubber compositions were coated onto a 25 μm thick polyimide film (Kapton EN, a product of Toray DuPont), and the solvent was dried at 140°C for 5 minutes to remove the solvent, resulting in an adhesive sheet with a coating thickness of 50 μm. Adhesive solution solubility test: After dissolving each component of the composition, the solution was left at room temperature for 3 hours and then the state of dissolution was observed. Visually check for layer separation. If no layer separation is observed, it is judged to be compatible and marked with a circle. If layer separation is observed, it is judged as incompatible and marked with ×. evaluation Curing test: Fluorine rubber composition is applied to a release film (Nitto Denko product Nitoflon No. 900UL) After drying the solvent at 140°C for 5 minutes, the thickness was 50 μ m, 1 at room temperature After vacuum drying for 1 hour, peel off the release film and stack 5 sheets to a thickness of 250 mm. μm sticky The adhesive sheet was placed on a curast meter manufactured by ENEOS Materials. Vulcanization was carried out at 170°C using a torsional vibration parallel die in accordance with JIS K 6300-2. Test and measure torque change The torque value increases as the crosslinking progresses. If an increase in the torque value is observed, it is judged to be cross-linked and marked with a circle. If no increase is observed, it is judged that no cross-linking has occurred and is evaluated as ×. Solvent resistance test: The adhesive sheet was immersed in methyl ethyl ketone at room temperature for 5 minutes. Visually check whether the adhesive has dissolved in methyl ethyl ketone. If it does not dissolve, it is judged that the fluororubber is crosslinked and marked with a circle. If it dissolves, it is determined that the fluororubber is not cross-linked and is marked as ×. evaluation Adhesion evaluation: Compliant with JIS Z0237 (inclined ball tack test) The film surface of the adhesive sheet is placed on a 30-degree slope. The No. 5 (diameter 4.8 mm) and No. 13 (diameter 10.3mm), No.19 (15.1mm diameter), No.25 (19.8mm diameter), No.32 (diameter Place steel balls (25.4 mm) on the test piece and check whether they roll. If it doesn't roll, it's evaluated as ○, and if it does roll, it's evaluated as ×. The larger the non-rolling steel ball, the greater the adhesiveness. Initial adhesion evaluation: JIS Z0237 compliant 25 μm thick polyimide film (Kapton EN), 0.2 mm thick SUS430 plate and 0.2 mm thick aluminum plate were After degreasing with ketone, the roll laminate was laminated at room temperature. 90° peel test (Test environment: 23°C ± 2°C, 50% RH ± 10% RH, test piece Shape: Width 10mm) and measure peel strength The higher the peel strength, the higher the adhesiveness, and 0.3 N / mm or more is preferable. Adhesion evaluation after heat resistance test: JIS Z0237 compliant 25 μm thick polyimide film (Kapton EN) and Laminate the Lurami at 100℃, then at 150℃ or 200℃. A 90° peel test was performed after 250 hours, 500 hours, and 1,000 hours. Measure the peel strength The higher the peel strength, the higher the heat resistance, and 0.3 N / mm or more is preferable.

[0100] The results obtained are shown in Tables 1 and 2 below. sticky As an evaluation test, the film surface of the adhesive sheet was attached to a sloped surface at an angle of 5 degrees using double-sided tape, and a No. 5 steel ball (diameter 4.8 mm) was placed on it to check whether it would roll. Table 1 Test and evaluation results Fruit 1 Fruit 2 Fruit 3 Fruit 4 Fruit 5 Fruit 6 Fruit 7 Fruit 8 Adhesive solution solubility test ○ ○ ○ ○ ○ ○ ○ ○ ○ Curing test 〇 〇 〇 〇 〇 〇 × 〇 Solvent resistance test 〇 〇 〇 〇 〇 〇 × 〇 [Adhesion Evaluation] No.5 Steel ball, angle 5 degrees 〇 〇 〇 〇 〇 〇 〇 〇 No.5 Steel ball, angle 30 degrees 〇 〇 〇 〇 〇 〇 〇 〇 No.13 steel ball, angle 30 degrees 〇 × 〇 〇 〇 〇 × × No.19 steel ball, angle 30 degrees 〇 × 〇 × × × × × No.25 steel ball, angle 30 degrees × × 〇 × × × × × No.32 steel ball, 30 degree angle × × × × × × × × [Initial adhesion] PI (N / mm) 0.55 0.38 0.84 0.31 0.46 0.31 0.30 0.35 Al (N / mm) 0.37 0.30 0.72 0.32 0.42 0.33 0.29 0.37 SUS (N / mm) 0.36 0.31 0.69 0.31 0.38 0.32 0.27 0.31 [Adhesion evaluation after heat resistance test] 150℃, 250 hours (N / mm) 0.82 0.76 0.69 0.62 0.66 0.72 0.40 1.73 150℃, 500 hours (N / mm) 1.27 0.82 0.75 0.98 1.10 1.07 0.45 1.51 150℃, 1000 hours (N / mm) 1.20 0.89 0.96 1.04 1.15 1.10 0.48 1.35 200℃, 250 hours (N / mm) 1.41 0.80 0.62 1.51 1.21 1.24 0.48 0.96 200℃, 500 hours (N / mm) 1.29 1.13 0.55 1.39 1.10 1.35 0.50 0.78 200℃, 1000 hours (N / mm) 1.00 0.74 0.45 1.20 0.90 1.23 0.55 0.54 Table 2 Test and evaluation results ratio 1 ratio 2 ratio 3 ratio 4 ratio 5 Adhesive solution solubility test 〇 × 〇 × 〇 Curing test 〇 × 〇 〇 〇 Solvent resistance test 〇 × 〇 〇 〇 [Adhesion Evaluation] No.5 Steel ball, angle 5 degrees 〇 〇 × × 〇 No.5 Steel ball, angle 30 degrees 〇 × × × × No.13 steel ball, angle 30 degrees 〇 × × × × No.19 steel ball, angle 30 degrees 〇 × × × × No.25 steel ball, angle 30 degrees 〇 × × × × No.32 steel ball, 30 degree angle × × × × × [Initial adhesion] PI (N / mm) 0.60 0.25 0.05 0.05 0.08 Al (N / mm) 0.55 0.15 0.02 0.03 0.05 SUS (N / mm) 0.53 0.12 0.03 0.02 0.04 [Adhesion evaluation after heat resistance test] 150℃, 250 hours (N / mm) 0.52 0.72 0.10 1.20 0.81 150℃, 500 hours (N / mm) 0.38 0.97 0.12 0.70 1.06 150℃, 1000 hours (N / mm) 0.28 1.10 0.14 1.20 1.25 200℃, 250 hours (N / mm) 0.13 1.21 0.15 1.30 1.25 200℃, 500 hours (N / mm) 0.05 1.10 0.17 0.50 1.15 200℃, 1000 hours (N / mm) 0.02 0.95 0.19 0.20 1.05

[0101] The above examples and comparative examples Results From this, the following can be said: (1) In each example in which modified fluororubber was used, the tackiness, adhesiveness, and heat resistance were high, and the tackiness and adhesiveness tended to increase as the amount of acrylic adhesive increased (Examples 1 to 3). (2) When a fluororubber modified with an organic alkali is used, higher tackiness and adhesiveness are obtained than when a fluororubber modified with an inorganic alkali is used (Examples 1 and 4). (3) The lower the glass transition temperature of the acrylic adhesive, the higher the adhesiveness tends to be (Examples 1 and 5). (4) When a diamine compound is further added, the adhesiveness is slightly reduced, but the heat resistance is improved (Examples 1 and 6). (5) When no crosslinking agent is used or when the amount is large, the adhesiveness tends to decrease (Example 1 ~2 , 7~8). (6) In the case of an acrylic adhesive that does not contain fluororubber, although adhesiveness is observed, the adhesive strength after the heat resistance test is low (Comparative Example 1). (7) When unmodified fluororubber is used, the initial adhesive strength and adhesiveness are low, and the solvent resistance is poor (Comparative Example 2). (8) When components having compositions generally used as fluororubber compositions are used, crosslinking occurs, but the initial adhesive strength is low and the adhesiveness is also low (Comparative Example 3). (9) When acrylic rubber was used instead of acrylic as the adhesive, the initial adhesive strength was low and no adhesiveness was observed (Comparative Example 4). (10) If an acrylic adhesive is not used, the initial adhesive strength is low and the adhesiveness is also low (Comparative Example 5).

[0102] As shown in the above results, in each comparative example, there are cases where the adhesiveness is low, the adhesive strength is small when attached at room temperature, and the heat resistance is poor, and it can be said that the adhesive cannot be used as an adhesive that exhibits heat resistance. [Industrial Applicability]

[0103] The fluororubber pressure-sensitive adhesive composition according to the present invention can be used for tapes, adhesives, electronic parts, automobile parts, industrial parts, etc. etc. Also used in chemical plants, vibration damping plates, vibration isolation plates, heat insulation materials, solar panels etc. It can be effectively used.

Claims

1. Mooney viscosity ML having unsaturated bonds or unsaturated bonds and functional groups 1+10 A fluoroelastomer adhesive composition in which a modified fluoroelastomer having a Tg (at 121°C) of 10 to 80 is blended with an acrylic adhesive containing an acrylic copolymer having a glass transition temperature Tg of 20°C or less.

2. 2. The fluororubber pressure-sensitive adhesive composition according to claim 1, wherein the functional group of the modified fluororubber is a carboxyl group.

3. The fluoroelastomer is an alkali-modified fluoroelastomer, and the Mooney viscosity after alkali modification is ML 1+10 The fluororubber pressure-sensitive adhesive composition according to claim 1, wherein the alkali-modified fluororubber has a hardness (121°C) that is 15 to 70°C lower than that before alkali modification.

4. 2. The fluororubber pressure-sensitive adhesive composition according to claim 1, wherein the weight average molecular weight Mw of the modified fluororubber is 300,000 or less.

5. 2. The fluororubber pressure-sensitive adhesive composition according to claim 1, wherein the weight average molecular weight Mw of the acrylic copolymer is 100,000 to 1,000,000.

6. The fluororubber adhesive composition according to any one of claims 1 to 5, wherein 100 parts by weight of the modified fluororubber is blended with 10 to 400 parts by weight of the acrylic adhesive.

7. The fluororubber pressure-sensitive adhesive composition according to claim 1, further comprising 1 to 50 parts by weight of a crosslinking agent per 100 parts by weight of the modified fluororubber.

8. 8. The fluororubber pressure-sensitive adhesive composition according to claim 7, wherein the crosslinking agent is a curable resin and / or an aromatic polyamine.

9. The fluororubber pressure-sensitive adhesive composition according to claim 7 or 8, further comprising imidazole as a crosslinking curing catalyst, in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the modified fluororubber.

10. The fluororubber pressure-sensitive adhesive composition according to claim 7, 8 or 9, wherein no acid acceptor is added.

11. An adhesive sheet in which the fluororubber composition according to claim 1 is laminated on one or both sides of a substrate.

12. 2. The fluororubber adhesive composition according to claim 1, which has such adhesiveness that when a steel ball having a diameter of 4.8 mm is placed on an adhesive surface formed on an inclined surface at an angle of 30 degrees, the steel ball does not roll off the adhesive surface.