Pressure-sensitive adhesive sheet, sealing material, and seal structure

Abstract

Provided is a pressure-sensitive adhesive sheet 10 made of a material having a first dynamic shear storage modulus G'0 higher than 1.0×106 Pa and a second dynamic shear storage modulus G'50 lower than 1.0×106 [Pa]. The first dynamic shear storage modulus G'0 is the dynamic shear storage modulus (G'), as measured at 1 Hz and 0°C, of the material of the pressure-sensitive adhesive sheet 10. The second dynamic shear storage modulus G'50 is the dynamic shear storage modulus (G'), as measured at 1 Hz and 0°C, of the material of the pressure-sensitive adhesive sheet 10.

Description

Adhesive sheets, sealing materials, and sealing structures

[0001] The present invention relates to a pressure-sensitive adhesive sheet, a sealing material, and a sealing structure.

[0002] 2. Description of the Related Art Conventionally, sealing materials provided with adhesive sheets have been known.

[0003] For example, Patent Document 1 describes a waterproof sealant having a layer of a predetermined pressure-sensitive adhesive composition on at least one surface of a foam structure having closed cells. The layer contains a polymer with a predetermined polycarbonate structure. This waterproof sealant has no tack, so it does not immediately adhere. After installation, the repulsive force of the foam structure causes the waterproof sealant to gradually adhere to the substrate, improving the sealability between the foam structure surface and the substrate interface. A waterproof test was conducted with a sample of the waterproof sealant sandwiched between two acrylic plates.

[0004] On the other hand, there are known pressure-sensitive adhesive sheets that are intended to be peeled off after being attached to an adherend. For example, Patent Document 2 describes a pressure-sensitive adhesive strip that can be reattached and detached without leaving any residue or breaking, essentially by stretching the adhesive surface. This pressure-sensitive adhesive strip comprises at least one adhesive layer foamed with microballoons and at least one carrier B. The pressure-sensitive adhesive A forming the adhesive layer comprises an elastomer portion (a1) based on at least one polyvinyl aromatic-polydiene block copolymer and a predetermined tackifying resin portion (a2). The pressure-sensitive adhesive A optionally comprises a softening resin portion (a3).

[0005] JP 10-77463 A JP 2018-138649 A

[0006] According to the descriptions in Patent Documents 1 and 2, it is not anticipated that the sealant will be used under conditions that require both the application of the sealant to a rough surface and the peeling off of the sealant at high speed.

[0007] Therefore, the present invention provides a pressure-sensitive adhesive sheet that is advantageous from the viewpoints of attaching a sealing material to a rough surface and peeling the sealing material at high speed.

[0008] The present invention provides a pressure-sensitive adhesive sheet, wherein a first dynamic shear storage modulus (G') of a material of the pressure-sensitive adhesive sheet at 1 Hz and 0°C is 1.0 x 10 6 Pa, and the second dynamic shear storage modulus (G') of the material at 1 Hz and 50°C is 1.0 x 10 6 The adhesive sheet has a compressive strength of less than 100 Pa.

[0009] The present invention also provides a sealing material comprising: the above-mentioned pressure-sensitive adhesive sheet; and a first layer covered with the pressure-sensitive adhesive sheet.

[0010] The present invention also provides a seal structure comprising: a first member; a second member; and the above-described seal material, wherein the seal material provides a seal between the first member and the second member.

[0011] The above-mentioned pressure-sensitive adhesive sheet is advantageous from the viewpoint of attaching a sealing material to a rough surface and peeling the sealing material off at high speed.

[0012] Fig. 1 is a cross-sectional view schematically showing an example of a pressure-sensitive adhesive sheet according to the present invention. Fig. 2 is a graph showing the relationship between the dynamic shear storage modulus (G') of a pressure-sensitive adhesive sheet material and temperature. Fig. 3 is a cross-sectional view schematically showing an example of a sealing material according to the present invention. Fig. 4 is a cross-sectional view schematically showing another example of a sealing material according to the present invention. Fig. 5 is a cross-sectional view schematically showing an example of a sealing structure according to the present invention.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0014] Fig. 1 is a cross-sectional view showing a schematic example of an adhesive sheet according to the present invention. The adhesive sheet 10 shown in Fig. 1 is made of a predetermined material. Fig. 2 shows the relationship between the dynamic shear storage modulus (G') and temperature of the material of the adhesive sheet 10. The material of the adhesive sheet 10 is a 1.0 x 10 6 Pa and a first dynamic shear storage modulus G'0 higher than 1.0 x 10 6 Second dynamic shear storage modulus G' lower than [Pa]50 The first dynamic shear storage modulus G'0 is the dynamic shear storage modulus (G') of the material of the PSA sheet 10 at 1 Hz and 0°C. The second dynamic shear storage modulus G' 50 is the dynamic shear storage modulus (G') of the material of the pressure-sensitive adhesive sheet 10 at 1 Hz and 0°C.

[0015] When sealing a component with a rough surface using a sealing material with an adhesive sheet, it is important that the sealing material adheres firmly to the rough surface. Furthermore, recycling of components with rough surfaces is considered important for environmentally conscious businesses. In this case, for example, it is assumed that the sealing material adhered to the component with a rough surface is peeled off and the component with a rough surface is recycled. To increase the efficiency of recycling components with rough surfaces, it is important to prevent the sealing material from breaking and part of the adhesive sheet from remaining on the rough surface even when the sealing material adhered to the component with a rough surface is peeled off at high speed.

[0016] For example, as shown in the graph of Fig. 2(b), if the adhesive sheet is made soft by increasing the tackiness in consideration of attaching a sealant to a rough surface, the adhesive sheet is easily broken and the sealant is difficult to peel off at high speed. On the other hand, as shown in Fig. 2(c), if the adhesive sheet is made hard by increasing the toughness in consideration of peeling off a sealant at high speed, the tackiness of the adhesive sheet is reduced, making it difficult to attach a sealant to a rough surface. Therefore, the present inventors have conducted extensive research to develop an adhesive sheet that is advantageous from the perspectives of both attaching a sealant to a rough surface and peeling off a sealant at high speed.

[0017] The application of a sealing material to a rough surface is highly related to the behavior of the adhesive sheet material at low speeds, and considering the temperature-time conversion law of viscoelastic behavior, it is thought to be highly related to the behavior of the material at high temperatures. On the other hand, the peeling of a sealing material at high speeds is highly related to the behavior of the adhesive sheet material at high speeds, and considering the temperature-time conversion law of viscoelastic behavior, it is thought to be highly related to the behavior of the material at low temperatures. Based on these considerations, the inventors have repeated extensive trial and error. As a result, the first dynamic shear storage modulus G'0 and the second dynamic shear storage modulus G' of the material contained in the adhesive sheet 10 are 50 It has been newly discovered that by satisfying the above conditions, the adhesive sheet 10 can exhibit advantageous properties from the viewpoints of both adhering a sealing material to a rough surface and peeling the sealing material off at high speed.

[0018] The dynamic shear storage modulus of the material of the pressure-sensitive adhesive sheet 10 can be measured, for example, according to the method described in the Examples. A sample for measuring the dynamic shear storage modulus of the material of the pressure-sensitive adhesive sheet 10 used in the sealing material described below can be prepared, for example, by cutting a part of the pressure-sensitive adhesive sheet 10 from the sealing material, or by dissolving the pressure-sensitive adhesive sheet 10 in a solvent, drying the resulting solution, and molding it into a predetermined shape.

[0019] The first dynamic shear storage modulus G' is 1.0 x 10 6 The first dynamic shear storage modulus G' is not limited to a specific value as long as it is higher than 1.0 x 10 Pa. 6 Pa, 5.0 × 10 7 The first dynamic shear storage modulus G' is 1.2 × 10 6 Pa or more, 1.5×10 6 Pa or more, 2.0×10 6 Pa or more, 2.5×10 6 Pa or more, 3.0×10 6 Pa or more, 5.0×10 6 Pa or more, or 1.0 x 10 7 The first dynamic shear storage modulus G' may be 4.5 x 10 Pa or more. 7 Pa or less, 4.0×10 7 Pa or less, 3.5×10 7 Pa or less, 3.0×107 Pa or less, 2.5×10 7 Pa or less, or 2.0 x 10 7 Pa or less.

[0020] Second dynamic shear storage modulus G' 50 is 1.0 x 10 6 The second dynamic shear storage modulus G' is not limited to a specific value as long as it is lower than 100 Pa. 50 is, for example, 1.0 × 10 5 Pa or more and 1.0 x 10 6 Lower than Pa. Second dynamic shear storage modulus G' 50 is 1.2 x 10 5 Pa or more, 1.5×10 5 Pa or more, 2.0×10 5 Pa or more, or 2.5 x 10 5 The second dynamic shear storage modulus G' may be equal to or greater than 100 Pa. 50 is 9.8 x 10 5 Pa or less, 9.5×10 5 Pa or less, 9.0×10 5 Pa or less, or 8.5 x 10 5 Pa or less.

[0021] In the pressure-sensitive adhesive sheet 10, the second dynamic shear storage modulus G' 50 The ratio of the first dynamic shear storage modulus G' to the first dynamic shear storage modulus G' / G' 50 The ratio G'0 / G' is not limited to a specific value. 50 is, for example, 4.0 or more. In this case, the pressure-sensitive adhesive sheet 10 is more likely to exhibit advantageous properties from the viewpoints of both attaching a sealing material to a rough surface and peeling the sealing material at high speed.

[0022] Ratio G'0 / G' 50 is preferably 4.5 or more, and more preferably 5 or more. 50 is, for example, 150 or less, and may be 140 or less, 120 or less, 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, or 55 or less.

[0023] The material of the adhesive sheet 10 is 1.0 × 10 6 Pa and a first dynamic shear storage modulus G'0 higher than 1.0 x 106 Second dynamic shear storage modulus G' lower than [Pa] 50 The pressure-sensitive adhesive sheet 10 is not limited to a specific material as long as it has the above properties. The pressure-sensitive adhesive sheet 10 includes, for example, a rubber-based polymer. The rubber-based polymer is, for example, a synthetic rubber such as a thermoplastic elastomer or a thermosetting elastomer.

[0024] Examples of thermoplastic elastomers include olefin-based elastomers, styrene-based elastomers, butyl-based elastomers, and vinyl chloride-based elastomers. Examples of olefin-based elastomers include ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM). Examples of styrene-based elastomers include styrene-butadiene rubber (SBR), styrene-butadiene-styrene rubber (SBS), styrene-isoprene-styrene rubber (SIS), styrene-ethylene-butadiene rubber, styrene-ethylene-butylene-styrene rubber (SEBS), styrene-isobutylene-styrene block rubber (SIBS), and styrene-isoprene-propylene-styrene rubber. Examples of butyl-based elastomers include butyl rubber, polyisobutylene rubber, polybutene, polyisoprene rubber, and nitrile butadiene rubber (NBR). Examples of vinyl chloride-based elastomers include chloroprene rubber or chlorosulfonated polyethylene rubber.

[0025] Examples of thermosetting elastomers are silicone rubber, fluororubber, acrylic rubber, and polyamide rubber.

[0026] The rubber-based polymer is preferably a thermoplastic elastomer, more preferably a styrene-based elastomer. When the rubber-based polymer is a styrene-based elastomer, the styrene-based elastomer preferably has 15 to 35% styrene units by mass. In this case, the PSA sheet 10 is more likely to exhibit advantageous properties from the perspectives of both attaching the sealant to a rough surface and peeling the sealant at high speed.

[0027] The weight-average molecular weight of the rubber-based polymer is, for example, 30,000 or more, preferably 50,000 or more, and more preferably 100,000 or more. The weight-average molecular weight of the rubber-based polymer is, for example, 5,000,000 or less, preferably 3,000,000 or less, and more preferably 1,000,000 or less. In this case, the surface formed by the pressure-sensitive adhesive sheet 10 is likely to have the desired adhesive strength. The weight-average molecular weight is measured in polystyrene equivalent terms using gel permeation chromatography.

[0028] The material of the pressure-sensitive adhesive sheet 10 contains, for example, an elastomer and a tackifier. The elastomer can be, for example, the rubber-based polymer described above.

[0029] The tackifier is not limited to a specific substance. The tackifier may be, for example, a specific resin. Examples of such resins include rosin-based tackifier resins, terpene-based tackifier resins, hydrocarbon-based tackifier resins, phenol-based tackifier resins, ketone-based tackifier resins, polyamide-based tackifier resins, epoxy-based tackifier resins, and elastomer-based tackifier resins. Examples of rosin-based tackifier resins include unmodified rosin, modified rosin, rosin phenol-based resins, and rosin ester-based resins. Examples of terpene-based tackifier resins include terpene-based resins, terpene-phenol-based resins, styrene-modified terpene-based resins, aromatic-modified terpene-based resins, and hydrogenated terpene-based resins. Examples of hydrocarbon-based tackifier resins include aliphatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic-aromatic petroleum resins, aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone-based resins, and coumarone-indene-based resins. Examples of aromatic hydrocarbon resins include styrene-based resins and xylene-based resins. Examples of phenolic tackifying resins are alkylphenolic resins, xylene formaldehyde resins, resols, and novolacs.The tackifier is preferably an alicyclic cyclic hydrocarbon or aromatic hydrocarbon resin.

[0030] The content of the tackifier in the pressure-sensitive adhesive sheet 10 is not limited to a specific value. For example, in the pressure-sensitive adhesive sheet, the ratio of the content of the tackifier to the content of the elastomer, such as a rubber-based polymer, on a mass basis is, for example, 0.5 to 1. This makes it easier for the pressure-sensitive adhesive sheet 10 to exhibit advantageous properties in terms of both attaching the sealant to a rough surface and peeling the sealant off at high speed.

[0031] The thickness of the pressure-sensitive adhesive sheet 10 is not limited to a specific value. The thickness is, for example, 50 to 400 μm. The thickness of the pressure-sensitive adhesive sheet 10 may be 70 μm or more, or 80 μm or more. The thickness of the pressure-sensitive adhesive sheet 10 may be 300 μm or less, or 250 μm or less.

[0032] It is possible to provide a sealing material including an adhesive sheet 10. As shown in Fig. 3, the sealing material 1a includes an adhesive sheet 10 and a first layer 20 covered with the adhesive sheet 10. The adhesive sheet 10 covers, for example, a part of the surface of the first layer 20. The material of the adhesive sheet 10 is, as described above, 1.0 x 10 6 Pa and a first dynamic shear storage modulus G'0 higher than 1.0 x 10 6 Second dynamic shear storage modulus G' lower than [Pa] 50 Therefore, the sealing material 1a is advantageous from the viewpoint of attaching the sealing material 1a to a rough surface and peeling the sealing material 1a at high speed.

[0033] 3, the sealing material 1a includes, for example, a pair of adhesive sheets 10, with a first layer 20 disposed between the pair of adhesive sheets 10. The pair of adhesive sheets 10 are disposed, for example, on both sides of the sealing material 1a in the thickness direction of the adhesive sheets 10. As a result, adhesive surfaces 11 made of the adhesive sheets 10 are formed on both surfaces of the sealing material 1a in the thickness direction of the adhesive sheets 10.

[0034] The material of the first layer 20 is not limited to a specific material. The first layer 20 is, for example, a foam. In this case, even if the gap to be sealed is large, the gap is easily filled with the sealing material 1a. In addition, since the first layer 20, which is a foam, can be compressed and deformed to fit the gap, it is easy to obtain a sealing structure that exhibits watertight properties using the sealing material 1a.

[0035] The structure of the foam is not limited to a specific structure. For example, the foam may have a closed-cell structure. In this case, the interior of the foam has high liquid-tightness, and the sealing material 1 a is likely to exhibit the desired water-stopping properties.

[0036] The foam may have, for example, a semi-closed cell structure. In this case, the foam contains open cells before compressive deformation, and when the foam is compressively deformed to a compressive strain of, for example, 50% or more, the open cells are closed, resulting in a change to a structure similar to a closed cell structure. The foam may have, for example, an open cell structure.

[0037] The material for the foam is not limited to a specific material. The foam may be, for example, a rubber foam or a resin foam. Examples of the resin foam include urethane foam, silicone foam, and acrylic foam.

[0038] The foam is preferably a rubber foam. In this case, even if the compression strain of the foam in the seal structure described below is small, the seal structure is likely to exhibit high water-stopping properties. The rubber foam can be obtained, for example, by foaming a rubber composition containing rubber, a foaming agent, and a crosslinking agent.

[0039] The rubber may be, for example, an olefin-based elastomer, a styrene-based elastomer, a butyl-based elastomer, a vinyl chloride-based elastomer, or natural rubber. Examples of olefin-based elastomers include ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM). Examples of styrene-based elastomers include styrene-butadiene rubber (SBR), styrene-butadiene-styrene rubber (SBS), styrene-isoprene-styrene rubber (SIS), styrene-ethylene-butadiene rubber, styrene-ethylene-butylene-styrene rubber (SEBS), styrene-isobutylene-styrene block rubber (SIBS), and styrene-isoprene-propylene-styrene rubber. Examples of butyl-based elastomers include butyl rubber, polyisobutylene rubber, polybutene, polyisoprene rubber, and nitrile butadiene rubber (NBR). Examples of vinyl chloride-based elastomers include chloroprene rubber and chlorosulfonated polyethylene rubber.

[0040] The rubber is preferably an olefin-based elastomer, more preferably EPDM, in which case the seal structure is more likely to exhibit high water-stopping properties even when the compressive strain of the foam in the seal structure is small.

[0041] EPDM is a rubber obtained by copolymerizing ethylene, propylene, and dienes. By copolymerizing dienes in addition to ethylene and propylene, unsaturated bonds are introduced, making it possible to crosslink the rubber with a crosslinking agent.

[0042] Examples of dienes include 5-ethylidene-2-norbornene, 1,4-hexadiene, and dicyclopentadiene. These dienes may be used alone or in combination of two or more. When the diene contains dicyclopentadiene, the degree of crosslinking can be improved.

[0043] The EPDM preferably has long chain branches. The method for introducing long branched chains into the EPDM is not limited to a specific method, and any known method can be used. If the EPDM has long chain branches, the rubber composition can be foamed well.

[0044] The diene content in the EPDM (diene content) is, for example, 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more. The diene content is, for example, 20% by mass or less, preferably 15% by mass or less. This makes the rubber foam less susceptible to surface shrinkage and cracking.

[0045] The foaming agent may be an organic foaming agent or an inorganic foaming agent.

[0046] Examples of organic blowing agents include azo blowing agents, N-nitroso blowing agents, hydrazide blowing agents, semicarbazide blowing agents, fluorinated alkane blowing agents, triazole blowing agents, and other known organic blowing agents. Examples of azo blowing agents include azodicarboxylic acid amide (ADCA), barium azodicarboxylate, azobisisobutyronitrile (AIBN), azocyclohexylnitrile, and azodiaminobenzene. Examples of N-nitroso blowing agents include N,N'-dinitrosopentamethylenetetramine (DTP), N,N'-dimethyl-N,N'-dinitrosoterephthalamide, and trinitrosotrimethyltriamine. Examples of hydrazide-based blowing agents include 4,4'-oxybis(benzenesulfonylhydrazide) (OBSH), paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 2,4-toluenedisulfonylhydrazide, p,p-bis(benzenesulfonylhydrazide) ether, and benzene-1,3-disulfonylhydrazide, allylbis(sulfonylhydrazide). Examples of semicarbazide-based blowing agents include p-toluenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide). Examples of fluorinated alkane-based blowing agents include trichloromonofluoromethane and dichloromonofluoromethane. An example of a triazole-based blowing agent is 5-morpholyl-1,2,3,4-thiatriazole. The organic blowing agent may be thermally expandable microparticles in which a thermally expandable substance is encapsulated in microcapsules. Examples of such thermally expandable fine particles include commercially available products such as Microsphere (trade name, manufactured by Matsumoto Yushi Co., Ltd.).

[0047] Examples of inorganic foaming agents include bicarbonates, carbonates, nitrites, borohydrides, inorganic azides, and other known inorganic foaming agents. Examples of bicarbonates include sodium bicarbonate and ammonium bicarbonate. Examples of carbonates include sodium carbonate and ammonium carbonate. Examples of nitrites include sodium nitrite and ammonium nitrite. Examples of borohydrides include sodium borohydride. These foaming agents may be used alone or in combination of two or more.

[0048] The amount of the foaming agent is, for example, 0.1 parts by mass or more, preferably 1 part by mass or more, and more preferably 10 parts by mass or more, relative to 100 parts by mass of rubber. The amount of the foaming agent is, for example, 50 parts by mass or less, and preferably 30 parts by mass or less.

[0049] Examples of crosslinking agents include sulfur compounds such as sulfur (S8) and 4,4'-dithiodimorpholine, selenium, magnesium oxide, lead monoxide, quinoid compounds such as p-quinone dioxime, p,p'-dibenzoylquinone dioxime, and poly-p-dinitrosobenzene, polyamines, nitroso compounds such as p-dinitrosobenzene, organic peroxides, resins, and ammonium salts such as ammonium benzoate. Examples of organic peroxides include dicumyl peroxide, dimethyldi(t-butylperoxy)hexane, 1,1-di(t-butylperoxy)cyclohexane, and α,α'-di(t-butylperoxy)diisopropylbenzene. Examples of resins include alkylphenol-formaldehyde resins and melamine-formaldehyde condensates. These crosslinking agents may be used alone or in combination.

[0050] The crosslinking agent is preferably sulfur (S8) and sulfur compounds, quinoid compounds, or organic peroxides. Sulfur (S8) and sulfur compounds are advantageous from the viewpoint of excellent mechanical strength and foaming properties. Quinoid compounds are advantageous from the viewpoint of reduced sulfur atom content, reduced corrosiveness, and excellent foaming properties. Organic peroxides are advantageous from the viewpoint of improved adhesion to the target object and step-conforming ability to realize a sealing structure.

[0051] The mixing ratio of the crosslinking agent is, for example, 0.05 parts by mass or more, preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, per 100 parts by mass of rubber. The mixing ratio of the crosslinking agent is, for example, 30 parts by mass or less, preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of rubber.

[0052] A quinoid compound and an organic peroxide may be used in combination as a crosslinking agent. In this case, sufficient crosslinking is likely to occur on the surface of the foam. When a quinoid compound and an organic peroxide are used in combination, the blending ratio of the organic peroxide is, for example, 1 part by mass or more, more preferably 10 parts by mass or more, per 100 parts by mass of the quinoid compound. The blending ratio is, for example, 100 parts by mass or less, more preferably 50 parts by mass or less, per 100 parts by mass of the quinoid compound.

[0053] The rubber composition desirably contains a foaming aid and a crosslinking aid. Examples of the foaming aid include urea-based foaming aids, salicylic acid-based foaming aids, benzoic acid-based foaming aids, and metal oxides such as zinc oxide. Preferred are urea-based foaming aids and metal oxides. These foaming aids may be used alone or in combination of two or more.

[0054] The blending ratio of the foaming aid is, for example, 0.5 parts by mass or more, and preferably 1 part by mass or more, per 100 parts by mass of rubber. The blending ratio is, for example, 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of rubber.

[0055] Examples of crosslinking coagents include thiazoles, thioureas, dithiocarbamic acids, guanidines, sulfenamides, thiurams, xanthic acids, aldehyde ammonia, and aldehyde amines. Among these, thiazoles, thioureas, dithiocarbamic acids, or thiurams are preferably used as crosslinking coagents. Examples of thiazoles include dibenzothiazyl disulfide and 2-mercaptobenzothiazole. Examples of thioureas include diethylthiourea, trimethylthiourea, and dibutylthiourea. Examples of dithiocarbamic acids include sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, and zinc dibenzyldithiocarbamate. Examples of guanidines include diphenylguanidine and di-o-tolylguanidine. Examples of sulfenamides are benzothiazyl-2-diethylsulfenamide and N-cyclohexyl-2-benzothiazylsulfenamide. Examples of thiurams are tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and tetrabenzylthiuram disulfide. Examples of xanthogenates are sodium isopropylxanthogenate and zinc isopropylxanthogenate. Examples of aldehyde ammonias are acetaldehyde ammonia and hexamethylenetetramine. Examples of aldehyde amines are n-butylaldehyde aniline and butyraldehyde monobutylamine.

[0056] The crosslinking aid may be an alcohol. Examples of alcohols include monohydric alcohols such as ethanol, dihydric alcohols such as ethylene glycol, trihydric alcohols such as glycerin, and polyols (polyoxyethylene glycols) such as polyethylene glycol and polypropylene glycol. As the alcohol, a polyol is preferably used. In this case, the number-average molecular weight of the polyol is, for example, 200 or more, preferably 300 or more. The number-average molecular weight of the polyol is, for example, 10,000 or less, preferably 5,000 or less.

[0057] These crosslinking aids may be used alone or in combination of two or more kinds.

[0058] When sulfur or a sulfur compound is used as the crosslinking agent, it is desirable to use a thiazole, a thiourea, a dithiocarbamic acid, or a thiuram as the crosslinking aid, from the viewpoint of ensuring a good foam shape and flexibility of the foam.

[0059] When a quinoid compound is used as the crosslinking agent, alcohols, more preferably polyols, are preferably used as the crosslinking aid from the viewpoint of reducing corrosiveness. In particular, when a p-quinonedioxime derivative is used as the quinoid compound, the use of polyethylene glycol is advantageous. When polyethylene glycol is used as the polyol, the rubber composition can be crosslinked well and excellent foamability can be easily ensured.

[0060] The mixing ratio of the cross-linking aid is, for example, 0.01 part by mass or more, preferably 0.02 part by mass or more, and more preferably 0.06 part by mass or more, per 100 parts by mass of rubber. The mixing amount is, for example, 20 parts by mass or less, preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of rubber.

[0061] The rubber composition may contain additives such as lubricants (processing aids), pigments, fillers, flame retardants, and softeners, as needed.

[0062] Examples of lubricants include stearic acid, its esters, stearin-based compounds such as zinc stearate, and paraffin. These lubricants may be used alone, or two or more types of lubricants may be used in combination. The blending ratio of the lubricant is, for example, 0.1 parts by mass or more, and preferably 1 part by mass or more, per 100 parts by mass of rubber. The blending ratio is, for example, 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of rubber.

[0063] An example of the pigment is carbon black. A single pigment may be used, or two or more pigments may be used in combination. The blending ratio of the pigment is, for example, 1 part by mass or more, and preferably 2 parts by mass or more, per 100 parts by mass of rubber. The blending ratio is, for example, 50 parts by mass or less, and preferably 30 parts by mass or less, per 100 parts by mass of rubber.

[0064] The filler may be an inorganic filler, an organic filler, or any other known filler. Examples of inorganic fillers include calcium carbonate, magnesium carbonate, silicic acid and its salts, clay, talc, mica powder, bentonite, silica, alumina, aluminum silicate, and aluminum powder. An example of an organic filler is cork. These fillers may be used alone, or two or more fillers may be used in combination. The compounding ratio of the filler is, for example, 10 parts by mass or more, preferably 30 parts by mass or more, and more preferably 50 parts by mass or more, per 100 parts by mass of rubber. The compounding ratio is, for example, 300 parts by mass or less, preferably 200 parts by mass or less, per 100 parts by mass of rubber.

[0065] Examples of flame retardants include hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide. These flame retardants may be used alone, or two or more types of flame retardants may be used in combination. The blending ratio of the flame retardant is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and more preferably 15 parts by mass or more, per 100 parts by mass of rubber. The blending ratio is, for example, 200 parts by mass or less, preferably 150 parts by mass or less, and more preferably 100 parts by mass or less, per 100 parts by mass of rubber.

[0066] Examples of softeners include petroleum oils, asphalts, low-molecular-weight polymers, organic acid esters, and thickeners. Examples of petroleum oils include paraffinic process oils such as paraffin oil, naphthenic process oils, drying oils or animal and vegetable oils, and aromatic process oils. An example of drying oils or animal and vegetable oils is linseed oil. Examples of organic acid esters include phthalate esters such as di-2-ethylhexyl phthalate (DOP) and dibutyl phthalate (DBP), phosphate esters, higher fatty acid esters, and alkyl sulfonates. Petroleum oils or asphalts are preferably used as softeners, and paraffinic process oils are more preferably used. These softeners may be used alone, or two or more types of softeners may be used in combination. The blending ratio of the softener is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, per 100 parts by mass of rubber. The compounding ratio is, for example, 300 parts by mass or less, and more desirably 200 parts by mass or less, per 100 parts by mass of rubber.

[0067] The rubber composition may contain known additives such as plasticizers, antioxidants, antioxidants, colorants, anti-fungal agents, and non-rubber polymers depending on the purpose and application.

[0068] The thickness of the sealing material 1a is not limited to a specific thickness. The sealing material 1a has a thickness of, for example, 1 to 40 mm. The thickness of the sealing material 1a may be 2 mm or more, 3 mm or more, or 5 mm or more. The thickness of the sealing material 1a may be 35 mm or less, 30 mm or less, 25 mm or less, or 20 mm or less.

[0069] A seal structure can be provided using the seal material 1a. As shown in FIG. 4, the seal structure 2 includes a first member 3a, a second member 3b, and a seal material 1a. In the seal structure 2, the seal material 1a seals between the first member 3a and the second member 3b. With this configuration, for example, even if the surfaces of the first member 3a and the second member 3b in contact with the seal material 1a are rough, the seal material 1a easily adheres to the rough surfaces. In addition, the seal material 1a can be easily peeled off at high speed from at least one of the first member 3a and the second member 3b.

[0070] 4, for example, at least one of the first member 3a and the second member 3b has a rough surface 32 in contact with the sealing material 1a. The arithmetic mean roughness R of the rough surface 32 determined in accordance with Japanese Industrial Standards (JIS) B0601:2013 is a is not limited to a specific value. The arithmetic mean roughness R of the rough surface 32 a is, for example, 0.3 μm or more. Even in such a case, the sealing material 1 a easily adheres to the rough surface 32. The arithmetic mean roughness R a is, for example, 1.0 μm or less.

[0071] The sealing material 1a may be stored or transported in various temperature environments before use. For example, it may be desirable for the adhesive strength of the sealing material 1a to be less susceptible to change even when stored or transported in a relatively high-temperature environment. From this perspective, the ratio F1 / F2 of the adhesive strength F1 [N / 15 mm] to the adhesive strength F2 [N / 15 mm] may be considered. The adhesive strength F1 [N / 15 mm] is the adhesive strength measured by attaching a sealing material 1a that has been left in a 60°C environment for 7 days alone to a polypropylene (PP) surface and then pulling the sealing material 1a in a direction that forms a 90° angle with respect to the PP surface to peel it off. The adhesive strength F2 is the adhesive strength measured by attaching an initial sample of the sealing material 1a that has not been left in a 60°C environment for 7 days to a PP surface and then pulling the sealing material 1a in a direction that forms a 90° angle with respect to the PP surface to peel it off. The adhesive strength F1 or F2 can be measured, for example, by the method described in the Examples.

[0072] As described above, the sealing material 1a may be placed in various temperature environments depending on the circumstances of storage or transportation before use, and is not necessarily stored or transported in a relatively high temperature environment. Therefore, the ratio F1 / F2 of the sealing material 1a is not limited to a specific value. The ratio F1 / F2 is, for example, 0.5 or more. In this case, even if the sealing material 1a is stored or transported in a relatively high temperature environment before use, the sealing material 1a will easily adhere to a rough surface. The ratio F1 / F2 may be less than 0.5.

[0073] The ratio F2 / F1 is preferably 0.55 or more, more preferably 0.6 or more, and even more preferably 0.65 or more. The ratio F2 / F1 is, for example, 1 or less.

[0074] The sealing material 1a can be modified from various viewpoints. For example, one of the pair of adhesive sheets 10 may be an adhesive sheet other than the adhesive sheet 10. In this case, the first dynamic shear storage modulus G'0 and the second dynamic shear storage modulus G' 50 is 1.0 x 10 6 [Pa] or more, and may be 1.0 × 10 6 [Pa] or less.

[0075] The sealing material 1a may be modified as shown in FIG. 5 as a sealing material 1b. The sealing material 1b is configured in the same manner as the sealing material 1a, except for portions that will be particularly described. The same reference numerals are used to designate components of the sealing material 1b that are the same as or correspond to components of the sealing material 1a, and detailed descriptions thereof will be omitted. The descriptions of the sealing material 1a also apply to the sealing material 1b, unless technically inconsistent.

[0076] 5, the sealing material 1b includes one adhesive sheet 10 and a foam first layer 20. The adhesive sheet 10 forms one end surface 11 of the sealing material 1b in the thickness direction. The first layer 20 forms the other end surface 12 of the sealing material 1b in the thickness direction.

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0078] Example 1 A mixture was obtained by kneading 100 parts by mass of SEBS resin Tuftec H1041 manufactured by Asahi Kasei Corporation and 80 parts by mass of tackifier T-REZ HA125 manufactured by ENEOS Corporation at 165°C. The styrene unit content in this SEBS resin was 30% by mass. This mixture was hot-pressed for 60 seconds under conditions of 170°C and 4 MPa and molded into a sheet having a thickness of 100 μm, thereby obtaining a pressure-sensitive adhesive sheet according to Example 1. A sheet having a thickness of 300 μm molded under the same conditions was also punched into a circle having a diameter of 8 mm to prepare an evaluation sample according to Example 1.

[0079] Three types of sealing materials 1A, 1B, and 1C were produced using the pressure-sensitive adhesive sheets according to Example 1. For sealing material 1A, Nitto Denko Corporation's Foam No. 6800 was placed between two pressure-sensitive adhesive sheets according to Example 1. For sealing material 1B, Nitto Denko Corporation's Foam EE-1000 was placed between two pressure-sensitive adhesive sheets according to Example 1. For sealing material 1C, one pressure-sensitive adhesive sheet according to Example 1 and one Nitto Denko Corporation's Foam EE-1000 were laminated together. Foam No. 6800 was an EPDM foam with a closed-cell structure and a thickness of 10 mm. Foam EE-1000 was an EPDM foam with an open-cell structure and a thickness of 10 mm. For each sealing material, a pressure of 2 kPa was applied to the laminate of the pressure-sensitive adhesive sheet and foam for 5 minutes in a 140°C oven to bond the pressure-sensitive adhesive sheet and foam together. In this way, three types of sealing materials according to Example 1 were obtained.

[0080] Example 2 A pressure-sensitive adhesive sheet according to Example 2 and an evaluation sample according to Example 2 were obtained in the same manner as Example 1, except for the following points. The blending ratios of the SEBS resin and tackifier were changed to 100 parts by mass and 60 parts by mass, respectively. A sealing material according to Example 2 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Example 2 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0081] Example 3 A pressure-sensitive adhesive sheet according to Example 3 and an evaluation sample according to Example 3 were obtained in the same manner as Example 1, except for the following points. As the tackifier, tackifier T-REZ HA105 was used instead of tackifier T-REZ HA125. A sealing material according to Example 3 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Example 3 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0082] Example 4 A pressure-sensitive adhesive sheet according to Example 4 and an evaluation sample according to Example 4 were obtained in the same manner as Example 1, except for the following points. As the tackifier, tackifier Alcon P-100 manufactured by Arakawa Chemical Industries, Ltd. was used instead of tackifier T-REZ HA125. Three types of sealing materials according to Example 4 were obtained in the same manner as sealing materials 1A, 1B, and 1C, except that the pressure-sensitive adhesive sheet according to Example 4 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0083] Example 5 A pressure-sensitive adhesive sheet according to Example 5 and an evaluation sample according to Example 5 were obtained in the same manner as Example 1, except for the following points. As the SEBS resin, Tuftec H1052 manufactured by Asahi Kasei Corporation was used instead of Tuftec H1041. The styrene unit content in this SEBS resin was 20% by mass. Three types of sealing materials according to Example 5 were obtained in the same manner as sealing materials 1A, 1B, and 1C, except that the pressure-sensitive adhesive sheet according to Example 5 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0084] Example 6 A pressure-sensitive adhesive sheet according to Example 6 and an evaluation sample according to Example 6 were obtained in the same manner as Example 1, except for the following points. As the SEBS resin, Tuftec H1062 manufactured by Asahi Kasei Corporation was used instead of Tuftec H1041. The styrene unit content in this SEBS resin was 18% by mass. A sealing material according to Example 6 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Example 6 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0085] Example 7 A pressure-sensitive adhesive sheet according to Example 7 and an evaluation sample according to Example 7 were obtained in the same manner as in Example 1, except for the following points. As the SEBS resin, a mixture of Tuftec H1062 and Tuftec H1517 was used instead of Tuftec H1041. In this mixture, the mass ratio of Tuftec H1062 to Tuftec H1517 was 80:20. The styrene unit content in this SEBS resin mixture was 23% by mass. A sealing material according to Example 7 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Example 7 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0086] Example 8 A pressure-sensitive adhesive sheet according to Example 8 and an evaluation sample according to Example 8 were obtained in the same manner as in Example 1, except for the following points. As the SEBS resin, a mixture of Tuftec H1062 and Tuftec H1517 was used instead of Tuftec H1041. In this mixture, the mass ratio of Tuftec H1062 to Tuftec H1517 was 75:25. The styrene unit content in this SEBS resin mixture was 24.3 mass%. Three types of sealing materials according to Example 8 were obtained in the same manner as sealing materials 1A, 1B, and 1C, except that the pressure-sensitive adhesive sheet according to Example 8 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0087] Example 9 A PSA sheet and an evaluation sample according to Example 9 were obtained in the same manner as in Example 1, except for the following points. As the SEBS resin, a mixture of Tuftec H1062 and Tuftec H1517 was used instead of Tuftec H1041. In this mixture, the ratio of the mass of Tuftec H1062 to the mass of Tuftec H1517 was 70:30. The styrene unit content in this SEBS resin mixture was 25.5 mass%. Three types of sealing materials according to Example 9 were obtained in the same manner as sealing materials 1A, 1B, and 1C, except that the PSA sheet according to Example 9 was used instead of the PSA sheet according to Example 1.

[0088] Example 10 A pressure-sensitive adhesive sheet according to Example 10 and an evaluation sample according to Example 10 were obtained in the same manner as in Example 1, except for the following points. As the SEBS resin, a mixture of Tuftec H1062 and Tuftec H1517 was used instead of Tuftec H1041. In this mixture, the ratio of the mass of Tuftec H1062 to the mass of Tuftec H1517 was 65:35. The styrene unit content in this SEBS resin mixture was 26.8 mass%. Three types of sealing materials according to Example 10 were obtained in the same manner as sealing materials 1A, 1B, and 1C, except that the pressure-sensitive adhesive sheet according to Example 10 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0089] <Comparative Example 1> A pressure-sensitive adhesive sheet according to Comparative Example 1 and an evaluation sample according to Comparative Example 1 were obtained in the same manner as in Example 1, except for the following points. Kraton D1155 SBS resin manufactured by Kraton Corporation was used instead of Tuftec H1041. Alcon M-115 manufactured by Arakawa Chemical Industries, Ltd. was used as the tackifier instead of T-REZ HA125. The blending ratios of the SBS resin and tackifier were adjusted to 100 parts by mass and 35 parts by mass. A sealing material according to Comparative Example 1 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Comparative Example 1 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0090] <Comparative Example 2> A pressure-sensitive adhesive sheet according to Comparative Example 2 and an evaluation sample according to Comparative Example 2 were obtained in the same manner as in Example 1, except for the following points. The blending ratios of the SEBS resin and tackifier were changed to 100 parts by mass and 120 parts by mass, respectively. A sealing material according to Comparative Example 2 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Comparative Example 2 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0091] <Comparative Example 3> A pressure-sensitive adhesive sheet according to Comparative Example 3 and an evaluation sample according to Comparative Example 3 were obtained in the same manner as in Example 1, except for the following points. The blending ratios of the SEBS resin and tackifier were changed to 100 parts by mass and 40 parts by mass, respectively. A sealing material according to Comparative Example 3 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Comparative Example 3 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0092] <Comparative Example 4> A pressure-sensitive adhesive sheet according to Comparative Example 4 and an evaluation sample according to Comparative Example 4 were obtained in the same manner as in Example 1, except for the following points. SEBS resin Kraton D1657 manufactured by Kraton Corporation was used instead of Tuftec H1041. As the tackifier, Alcon M-115 manufactured by Arakawa Chemical Industries, Ltd. was used instead of T-REZ HA125. The blending ratios of the SEBS resin and tackifier were adjusted to 100 parts by mass and 60 parts by mass. A sealing material according to Comparative Example 4 was obtained in the same manner as sealing material 1A, except that the pressure-sensitive adhesive sheet according to Comparative Example 4 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0093] (Dynamic Viscoelasticity Measurement) The evaluation samples of each Example and Comparative Example were clamped between stainless steel jigs with a diameter of 8 mm, and dynamic viscoelasticity measurements were performed under the following conditions using a rotational rheometer ARES-G2 manufactured by TA Instruments Co., Ltd. Based on the measurement results, the dynamic shear storage modulus G'0 at 0°C and 1 Hz and the dynamic shear storage modulus G' at 50°C and 1 Hz were calculated. 50 The results are shown in Tables 1A, 1B, 1C, 1D, and 2. Measurement mode: shear Frequency: 1 Hz Axial load: 0.02 N Temperature range: -50 to 180°C Heating rate: 5°C / min

[0094] (Rough Surface Adhesion Test) The sealing materials according to each Example and Comparative Example were cut into rectangular shapes having a width of 20 mm and a length of 150 mm in plan view to prepare test pieces for the rough surface attachment test. The surface of a SUS304 steel plate was polished for 30 seconds with a sander polisher equipped with #600 sandpaper to form a rough surface. The arithmetic mean roughness R of the rough surface determined in accordance with JIS B0601:2013 was aThe thickness of the steel plate was 0.4 mm, and the steel plate was rectangular in shape with a width of 40 mm and a length of 200 mm in a plan view. With the surface of the adhesive sheet of the test piece in contact with the rough surface of the steel plate, a 2 kg roller was moved back and forth once on the test piece to press the test piece against the rough surface. 10 seconds after the test piece was pressed against the rough surface, the steel plate with the sealing material attached was tilted sideways and the edge of the steel plate was struck 10 times on a desk, and the adhesion of the sealing material was evaluated according to the following criteria: Good: The sealing material was attached to the steel plate without any gaps. Not enough: The sealing material slipped off the steel plate, or a gap was observed between part of the sealing material and the rough surface of the steel plate.

[0095] (High-Speed ​​Peel Test) The sealing material according to each Example and Comparative Example was cut into a rectangular shape having a width of 20 mm and a length of 150 mm in plan view to prepare a test specimen for the high-speed peel test. With the surface of the adhesive sheet of this test specimen in contact with the surface of the steel plate, a 2 kg roller was moved back and forth over the test specimen once to press the test specimen onto the surface of the steel plate. The steel plate had a thickness of 0.4 mm and a rectangular shape having a width of 40 mm and a length of 200 mm in plan view. After pressing the test specimen onto the surface of the steel plate, the test specimen and steel plate were left to stand for 24 hours in an environment of 23°C and 50% relative humidity. The test specimen was then peeled from the surface of the steel plate at a speed of 30 m / min and an angle of 30°. The ease of high-speed peeling was evaluated according to the following criteria: Good: The sealing material did not break, and no adhesive sheet was observed to remain on the steel plate. Not enough: The sealing material broke, or adhesive sheet was observed to remain on the steel plate.

[0096] The sealing material according to each example was punched into a ring shape with an inner diameter of 50 mm and an outer diameter of 70 mm to prepare a test specimen for the IPX7 test. The test specimen was placed between two acrylic plates, and spacers were placed around the test specimen between the two acrylic plates to fix the test specimen in a state where a predetermined compressive strain was generated in the thickness direction of the acrylic plates. The acrylic plates were Acrylite EX manufactured by Mitsubishi Chemical Corporation and had a thickness of 10 mm. In this manner, a sample for the IPX7 test was prepared. Acrylite is a registered trademark. The sample was submerged in a water tank filled to a height of 1 m, and after 30 minutes, the sample was removed and the presence or absence of water leakage into the inside of the ring-shaped test specimen was confirmed to determine whether it met the IPX7 standard. If there was no water leakage, it was evaluated as meeting the IPX7 standard.

[0097] (Adhesion Strength After Storage) Each of the sealing materials according to Examples 6 to 10 was cut into a rectangular shape measuring 15 mm wide and 150 mm long in a plan view, and the cut pieces were then placed in a thermostatic chamber set at 60°C for 7 days to obtain a preserved sample. Furthermore, each of the sealing materials according to Examples 6 to 10 was cut into a rectangular shape measuring 15 mm wide and 150 mm long in a plan view, and an initial sample was obtained without being placed in a thermostatic chamber set at 60°C for 7 days. Each sample thus obtained was placed in contact with the surface of a polypropylene (PP) plate, and a 2 kg roller was moved back and forth over the sample once to press the sample onto the surface of the PP plate. The PP plate had a rectangular surface measuring 40 mm wide and 200 mm long in a plan view, and a thickness of 2 mm. Each sample pressed onto the PP plate was placed in an environment at 23°C and 50% relative humidity for 24 hours. The sample was then pulled at a speed of 300 mm / min in a direction forming an angle of 90° with respect to the surface of the PP plate using a Shimadzu Autograph universal testing machine, and the adhesive strengths F1 and F2 were measured. The results are shown in Tables 1C and 1D.

[0098] As shown in Tables 1A, 1B, 1C, 1D, and 2, the sealants according to each example were evaluated as Good in the rough surface application test and the high-speed peel test. The sealants according to Comparative Examples 1 and 3 were evaluated as Good in the high-speed peel test, but were evaluated as Not sufficient in the rough surface application test. Furthermore, the sealants according to Comparative Examples 2 and 4 were evaluated as Good in the rough surface application test, but were evaluated as Not sufficient in the high-speed peel test. Comparing the examples and comparative examples, it was found that the dynamic shear storage modulus G'0 at 0°C and 1 Hz of the material of the adhesive sheet of the sealant was 1.0 x 10 6 Dynamic shear storage modulus G' at 50°C and 1 Hz is higher than 50 is 1.0 x 10 6 It is understood that if the compressive strength is lower than 100 Pa, the sealing material is advantageous from the viewpoint of adhesion to a rough surface and peeling off at high speed.

[0099] According to Tables 1C and 1D, the ratio (F1 / F2) of the adhesive strength (F2) of the initial sample to the surface of the PP plate (F1) of the preserved sample was 0.5 or more for the sealing members of Examples 6 to 10. Therefore, it is believed that these sealing materials are likely to maintain high adhesive strength even when stored or transported at relatively high temperatures before use, making it easy to attach the sealing members to rough surfaces.

[0100] A first aspect of the present invention is a pressure-sensitive adhesive sheet, wherein a first dynamic shear storage modulus (G') of a material of the pressure-sensitive adhesive sheet at 1 Hz and 0°C is 1.0 x 10 6 Pa, and the second dynamic shear storage modulus (G') of the material at 1 Hz and 50°C is 1.0 x 10 6 The adhesive sheet has a compressive strength of less than 100 Pa.

[0101] A second aspect of the present invention provides the pressure-sensitive adhesive sheet according to the first aspect, wherein the ratio of the first dynamic shear storage modulus (G') to the second dynamic shear storage modulus (G') is 4.0 or greater.

[0102] A third aspect of the present invention provides a PSA sheet according to the first or second aspect, wherein the material includes a styrene-based elastomer having 15 to 35% by mass of styrene units.

[0103] A fourth aspect of the present invention provides the PSA sheet according to any one of the first to third aspects, wherein the material comprises an elastomer and a tackifier, and the ratio of the content of the tackifier to the content of the elastomer is 0.5 to 1 by mass.

[0104] A fifth aspect of the present invention provides a sealing material comprising: the pressure-sensitive adhesive sheet according to any one of the first to fourth aspects; and a first layer covered with the pressure-sensitive adhesive sheet.

[0105] A sixth aspect of the present invention provides the sealing material according to the fifth aspect, wherein the first layer is a foam.

[0106] A seventh aspect of the present invention provides the sealing material according to the fifth or sixth aspect, wherein the sealing material has a thickness of 1 to 40 mm.

[0107] An eighth aspect of the present invention provides a seal structure comprising: a first member; a second member; and a seal material relating to the fifth to seventh aspects, wherein the seal material seals between the first member and the second member.

[0108] In a ninth aspect of the present invention, at least one of the first member and the second member has a rough surface in contact with the sealing material, and an arithmetic mean roughness R of the rough surface determined in accordance with Japanese Industrial Standards (JIS) B0601:2013 is a is 0.3 μm or more.

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Claims

1. An adhesive sheet, wherein a first dynamic shear storage modulus (G') of a material of the adhesive sheet at 1 Hz and 0°C is 1.0 x 10 6 A second dynamic shear storage modulus (G') of the material at 1 Hz and 50°C is greater than 1.0 x 10 Pa. 6 Adhesive sheet with a viscosity lower than Pa.

2. The pressure-sensitive adhesive sheet according to claim 1, wherein the ratio of the first dynamic shear storage modulus (G') to the second dynamic shear storage modulus (G') is 4.0 or more.

3. The pressure-sensitive adhesive sheet according to claim 1, wherein the material contains a styrene-based elastomer having 15 to 35% styrene units by mass.

4. The adhesive sheet according to claim 1, wherein the material comprises an elastomer and a tackifier, and the ratio of the content of the tackifier to the content of the elastomer is 0.5 to 1 on a mass basis.

5. A sealing material comprising the adhesive sheet according to any one of claims 1 to 4 and a first layer covered with the adhesive sheet.

6. The sealing material according to claim 5, wherein the first layer is a foam.

7. The sealing material according to claim 5, wherein the sealing material has a thickness of 1 to 40 mm.

8. A seal structure comprising: a first member; a second member; and the seal material according to claim 5, wherein the seal material provides a seal between the first member and the second member. At least one of the first member and the second member has a rough surface in contact with the sealing material, and the arithmetic mean roughness R of the rough surface is determined in accordance with Japanese Industrial Standards (JIS) B0601:2013. a The seal structure according to claim 8 , wherein the thickness of the groove is 0.3 μm or more.

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