Seal material

Abstract

To provide a seal material bonded to an adherend and advantageous from the viewpoint of being peeled from the adherend after being exposed to high temperature environment for a long term.SOLUTION: A seal material 1a having a thickness t of 1-40 mm includes a surface part 10e including an end surface 11 in the thickness direction of the seal material 1a and having a thickness of 300 μm. The surface part 10e having a breaking strain of 500% satisfies the condition of a tensile force FA [N / 20 mm]>an adhesive power FB [N / 20 mm]; the tensile force FA is represented as F1 tA 20 / S1; and the adhesive power FB is a 90° peeling adhesive power [N / 20 mm] measured after peeling the specimen from the test plate based on JIS Z 0237:2022 after keeping the environmental temperature of a specimen prepared from the seal material 1a at 100°C for 7 days in the state of bonding the specimen to a test plate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sealing material. [Background technology]

[0002] 2. Description of the Related Art Conventionally, sealing materials capable of filling gaps and achieving watertightness have been known.

[0003] For example, Patent Document 1 describes a waterproof sealant having a layer of a specific adhesive composition on at least one surface of a foam structure having closed cells. The layer contains a polymer having a specific polycarbonate structure. This waterproof sealant does not adhere immediately because it has no tack. After the waterproof sealant is attached, the waterproof sealant gradually adheres to the adherend due to the repulsive force of the foam structure, and the sealability between the foam structure surface and the adherend interface is improved. A waterproof test is performed 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 without residue or destruction by substantially extensible stretching on 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 aromatics-polydiene-block copolymer and a predetermined tacky resin portion (a2). The pressure-sensitive adhesive A optionally comprises a softened resin portion (a3).

[0005] Patent Document 3 describes an adhesive attachment assembly that can be attached or adhered to a surface and can be peeled off from the surface without damaging the surface. The adhesive attachment assembly includes a backing, a first adhesive region, a second adhesive region, a non-adhesive region, and an attachment device. The first adhesive region and the second adhesive region are regions on a first major flat surface of the backing. The non-adhesive region is, for example, disposed between the first adhesive region and the second adhesive region. The attachment device is adjacent to the backing. The non-adhesive region is, for example, adjacent to the attachment device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-77463 [Patent Document 2] JP 2018-138649 A [Patent Document 3] Special Publication No. 2019-534059 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, it is not assumed that the waterproof sealant will be peeled off after the waterproof sealant is sufficiently adhered to the adherend and the sealability between the foam structure surface and the adherend interface is high. In addition, Patent Document 1 does not assume that the waterproof sealant attached to the adherend will be exposed to a high-temperature environment for a long period of time. Patent Documents 2 and 3 do not assume that the sealant will be exposed to a high-temperature environment for a long period of time after being attached to the adherend. These technologies have room for reexamination from the viewpoint of peeling off the sealant after being exposed to a high-temperature environment for a long period of time.

[0008] Therefore, the present invention provides a sealing material that is advantageous from the viewpoint of peeling from an adherend after being attached to the adherend and exposed to a high-temperature environment for a long period of time. [Means for solving the problem]

[0009] The present invention relates to A sealing material, The sealing material has a thickness of 1 to 40 mm, The sealing material includes an end surface in a thickness direction of the sealing material, and A surface portion having a thickness of 300 μm, The surface portion has a breaking strain of 500% or more, and Tensile force F A [N / 20mm]>Adhesive force F B Meets the condition of [N / 20mm], The tensile force F A is the maximum test force F in the tensile test performed on the test piece made from the surface portion 1 [N], the cross-sectional area S of the test piece 1 [mm 2 ], and the thickness t of the surface portion A F by [mm] 1 t A 20 / S 1 It is expressed as The test piece in the tensile test is rectangular in shape having a width of 10 mm and a length of 40 mm in a plan view, The chuck distance in the tensile test was 10 mm. The test speed in the tensile test was 1000 mm / min. The adhesive strength F B is a 90° peel adhesion strength [N / 20 mm] measured by attaching a test piece made of the sealing material to a test plate, maintaining the environmental temperature of the test piece at 100°C for 7 days, and then peeling the test piece from the test plate in accordance with Japanese Industrial Standards (JIS) Z 0237:2022. A sealant is provided. Effect of the Invention

[0010] The above-mentioned sealing material is advantageous from the viewpoint of peeling it off from the adherend after it has been attached to the adherend and exposed to a high-temperature environment for a long period of time. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view that illustrates an example of a sealing material according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view that illustrates a typical example of the use of the sealing material. [Figure 3A] FIG. 3A is a side view showing an example of a method for peeling off the sealing material. [Figure 3B] FIG. 3B is a plan view showing an example of a method for peeling off the sealing material. [Figure 4A] FIG. 4A is a graph showing the tensile force F [N / 20 mm] in the tensile test as a function of strain. [Figure 4B] FIG. 4B is a graph showing the tensile force F [N / 20 mm] in the tensile test as a function of strain. [Diagram 5] FIG. 5 is a cross-sectional view illustrating a schematic diagram of another example of the sealing material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following embodiments.

[0013] As shown in FIG. 1, the sealing material 1a has a thickness t of 1 to 40 mm. The sealing material 1a has a surface portion 10e. The surface portion 10e is a portion that includes an end face 11 in the thickness direction of the sealing material 1a and has a thickness of 300 μm. In other words, the range of 300 μm from the end face 11 in the thickness direction of the sealing material 1a is defined as the surface portion 10e. The surface portion 10e has a breaking strain of 500%. In addition, the surface portion 10e has a tensile force F A [N / 20mm]>Adhesive force F B [N / 20mm]. Tensile force F A is the maximum test force F in a tensile test performed on a test piece made from the surface portion 10e 1 [N], the cross-sectional area of ​​the specimen S 1 [mm 2 ], and the thickness t of the surface portion 10e AF by [mm] 1 t A 20 / S 1 The test piece in this tensile test is rectangular with a width of 10 mm and a length of 40 mm in plan view. The chuck distance in the tensile test is 10 mm. The test speed in the tensile test is 1000 mm / min. The tensile test is performed in accordance with, for example, Japanese Industrial Standards (JIS) K6251, except where otherwise specified. Adhesion strength F B is the 90° peel adhesion strength [N / 20 mm] measured by attaching a test piece made of the sealing material 1a to a test plate, maintaining the environmental temperature of the test piece at 100°C for 7 days, and then peeling the test piece from the test plate in accordance with JIS Z 0237:2022.

[0014] As shown in FIG. 2, a seal structure 2 can be provided using a seal material 1a. For example, the seal material 1a is pressed between an adherend 3a and an adherend 3b to obtain the seal structure 2. The seal structure 2 can exhibit, for example, waterproofness conforming to IPX7. The seal structure 2 can be exposed to a high-temperature (e.g., 100° C. or higher) environment for a long period of time (e.g., 168 hours or more). In addition, the seal material 1a can be peeled off from the adherends 3a and 3b and collected after use of the seal structure 2. This leads to promoting recycling of the adherends 3a and 3b, and is also desirable from the viewpoint of environmental protection.

[0015] For example, when the seal material 1a is peeled off from the adherend 3a, as shown in FIGS. 3A and 3B, the seal material 1a is peeled off in a direction D P In this case, the force is pulled in the direction D P The acute angle that the sealing material 1a extending along the line forms with the surface of the adherend 3a is, for example, 5 to 70°.

[0016] According to the study by the present inventors, when the gap between the adherends is large, it is complicated and difficult to say that it is practical to fill the gap using a double-sided adhesive tape. For this reason, for example, it is possible to fill the gap between the adherends using a sealing material having a thickness of 1 to 40 mm. In this case, for example, in order for the sealing material to exhibit water-stopping properties, it is necessary that the end face of the sealing material in the thickness direction and the adherend surface are in a watertight state. For this reason, it is considered that the adhesive force of the end face of the sealing material in the thickness direction to the adherend is large, which is advantageous for exhibiting water-stopping properties. On the other hand, as shown in Figures 3A and 3B, it is possible to peel the sealing material from the adherend in order to recycle the adherend. In this case, it is important that the sealing material does not break when peeled off, and that no part of the sealing material remains on the adherend. However, if the sealing material is exposed to a high-temperature environment for a long period of time while it is attached to the adherend, the sealing material is likely to break when peeled off from the adherend, and recovery by peeling off the sealing material may be complicated. In addition, a portion of the sealing material is likely to remain on the adherend, and there is a concern that the adhesive and other substances remaining on the adherend may hinder recycling of the adherend.

[0017] Since the sealing material 1a has a thickness of 1 to 40 mm, even if the gap between the adherends is large, the gap can be easily filled. As described above, the surface portion 10e of the sealing material 1a has a breaking strain of 500% or more and a tensile strength F A [N / 20mm]>Adhesive force F B [N / 20mm] is satisfied. As a result, even if the sealing material 1a is attached to an adherend and exposed to a high-temperature environment for a long period of time, and then peeled off from the adherend, the sealing material 1a is unlikely to break and a portion of the sealing material 1a is unlikely to remain on the adherend. This makes it easy to recover the sealing material 1a.

[0018] Since the breaking strain of the sealing material 1a is 500% or more, constriction is likely to occur when the sealing material 1a is peeled off, as shown in Fig. 3B. The occurrence of such constriction reduces the adhesive area between the adherend and the sealing material 1a, so that the sealing material 1a is peeled off in a state in which it is difficult for a portion of the sealing material 1a to remain on the adherend.

[0019] In the sealing material 1a, for example, both surface portions 10e in the thickness direction of the sealing material 1a have a breaking strain of 500% or more, and a tensile force F A [N / 20mm]>Adhesive force F B In the sealing material 1a, only one surface portion 10e in the thickness direction of the sealing material 1a has a breaking strain of 500% or more and satisfies the condition of [N / 20 mm]. A [N / 20mm]>Adhesive force F B The surface portion 10e may satisfy the condition of [N / 20mm]. A [N / 20mm]>Adhesive force F B Whether the condition [N / 20mm] is satisfied or not is determined by attaching the test piece so that the surface portion 10e is in contact with the test plate and measuring the adhesive force F B It is determined by measuring

[0020] The thickness t of the sealing material 1a may be 2 mm or more, 3 mm or more, or 5 mm or more. The thickness t may be 35 mm or less, 30 mm or less, 25 mm or less, or 20 mm or less.

[0021] The breaking strain of the surface portion 10e may be 600% or more, 700% or more, 800% or more, 900% or more, 1000% or more, 1100% or more, 1200% or more, 1300% or more, 1400% or more, 1500% or more, 1600% or more, 1800% or more, 1900% or more, or 2000% or more.

[0022] The breaking strain of the surface portion 10e is, for example, 5000% or less. This makes it easy to prevent the amount of strain of the sealant 1a from becoming too large when the sealant 1a is peeled off from the adherend after the sealant 1a is exposed to a high-temperature environment for a long period of time while attached to the adherend. The breaking strain of the surface portion 10e may be 4900% or less, 4800% or less, 4700% or less, 4600% or less, 4500% or less, 4400% or less, 4300% or less, 4200% or less, 4100% or less, or 4000% or less.

[0023] Tensile force F A [N / 20mm] is the tensile force F A [N / 20mm]>Adhesive force F B There is no specific limit as long as the condition [N / 20mm] is met. A [N / 20mm] may be, for example, 10N / 20mm or more, 20N / 20mm or more, 25N / 20mm or more, or 30N / 20mm or more. A [N / 20mm] is, for example, 100N / 20mm or less, and may be 90N / 20mm or less, or 80N / 20mm or less.

[0024] Adhesive force F B [N / 20mm] is the tensile force F A [N / 20mm]>Adhesive force F B There is no specific limit as long as the condition [N / 20mm] is met. Adhesive strength F B [N / 20mm] is, for example, 5N / 20mm or more, and may be 10N / 20mm or more, 12N / 20mm or more, or 15N / 20mm or more. B [N / 20mm] is, for example, 80N / 20mm or less, and may be 75N / 20mm or less, or 70N / 20mm or less.

[0025] Tensile force F A [N / 20mm] to adhesive strength F B The difference after subtracting [N / 20mm] is the tensile force F A [N / 20mm]>Adhesive force F BThere is no restriction on the value as long as the condition [N / 20mm] is satisfied. A -F B is, for example, 0.5 [N / 20 mm] or more, and may be 1.0 [N / 20 mm] or more, or 1.5 [N / 20 mm] or more.

[0026] Difference F A -F B may be, for example, 60 [N / 20 mm] or less, 55 [N / 20 mm] or less, 50 [N / 20 mm] or less, or 45 [N / 20 mm] or less.

[0027] 4A and 4B are graphs showing the tensile force F [N / 20 mm] as a function of strain in a tensile test performed on a test piece made from the surface portion 10e. The tensile force F is the test force F 2 [N], cross-sectional area of ​​the test piece S 1 [mm 2 ], and the thickness t of the surface portion 10e A F by [mm] 2 t A 20 / S 1 This is expressed as:

[0028] In a tensile test, the surface portion 10e has an average rate of change R of, for example, 1.5 [N / 20 mm] or more. AV This results in a tensile force F A [N / 20mm]>Adhesive force F B The condition of [N / 20 mm] is easily satisfied in a desired state. Therefore, even if the sealing material 1a is attached to an adherend and exposed to a high-temperature environment for a long period of time, and then the sealing material 1a is peeled off from the adherend, the sealing material 1a is less likely to break.

[0029] Average rate of change R AVis the ratio of the change in tensile force F [N / 20 mm] to the change in strain in the range of test force ratios from 40% to 60% in a tensile test on a test piece made from the surface portion 10e. In this case, the strain is not a value expressed as a percentage, but a value obtained by expressing the ratio of the deformation amount of the test piece to the original length, with the original length set to 1. In FIG. 4A, the tensile force F 40 is the tensile force F corresponding to a test force ratio of 40%, and the tensile force F 60 is the tensile force F corresponding to a test force ratio of 60%. In Fig. 4A, point P 40 and P 60 are the tensile force F [N / 20mm] as a function of strain, respectively. 40 and F 60 It corresponds to point P 40 and P 60 The strains corresponding to a [%] and ε b The average rate of change is expressed as [%]. AV is expressed by the following formula (1). R AV =(F 60 -F 40 ) / (ε b -ε a ) Formula (1)

[0030] Average rate of change R AV may be 1.6 [N / 20mm] or more, 1.7 [N / 20mm] or more, or 1.8 [N / 20mm] or more. AV is, for example, 15 [N / 20mm] or less, and may be 14 [N / 20mm] or less, 13 [N / 20mm] or less, 12 [N / 20mm] or less, 10 [N / 20mm] or less, or 5 [N / 20mm] or less. AV may be less than 1.5 [N / 20mm].

[0031] The surface portion 10e has a specific strain ε of, for example, 2500% or less in a tensile test. C As shown in FIG. 4B, the specific strain ε Cis the intersection point Q of the first line L1 and the second line L2 in a graph showing the tensile force F [N / 20 mm] as a function of strain. C The first straight line L1 corresponds to a pair of points Q on the graph above where the strain ratios are 20% and 30%. 20 and Q 30 The strain ratio is the straight line that passes through the breaking strain ε B In Figure 4B, ε 20 and ε 30 are the strains corresponding to strain ratios of 20% and 30%, respectively. The second line L2 is a pair of points Q 80 and Q 30 In FIG. 4B, ε 80 and ε 90 are the strains corresponding to strain ratios of 80% and 90%, respectively.

[0032] Specific strain ε C may be 2400% or less, 2300% or less, 2200% or less, 2100% or less, 2000% or less, 1900% or less, or 1800% or less. C is preferably 1800% or less. In this case, the tensile force F A [N / 20mm]>Adhesive force F B The condition of [N / 20 mm] is easily satisfied in a desired state. Therefore, even if the sealing material 1a is attached to an adherend and exposed to a high-temperature environment for a long period of time, and then the sealing material 1a is peeled off from the adherend, the sealing material 1a is less likely to break.

[0033] Specific strain ε C is, for example, 300% or more, and may be 400% or more, 500% or more, 600% or more, 700% or more, 800% or more, 900% or more, 1000% or more, 1100% or more, or 1200% or more.

[0034] 4B, for example, the inclination of the second straight line L2 is greater than the inclination of the first straight line L1. The inclination of the first straight line L1 is, for example, 0.1 to 1 [N / 20 mm]. The inclination of the second straight line L2 is, for example, 2 to 8 [N / 20 mm].

[0035] The tensile modulus of the material constituting the end surface 11 of the seal material 1a is not limited to a specific value. The tensile modulus is, for example, less than 6.5 MPa. In this case, in a seal structure using the seal material 1a, the space between the end surface 11 and the adherend surface is likely to be watertight. The tensile modulus of the material constituting the end surface 11 is preferably 6.0 MPa or less, and more preferably 5.5 MPa or less.

[0036] 1, the sealing material 1a has, for example, at least two layers, which makes it possible for the sealing material 1a to easily fill in the gap between the adherends even if the gap is large.

[0037] As shown in FIG. 1, the sealing material 1a includes, for example, a foam 20. This allows the sealing material 1a to easily fill the gap between the adherends even if the gap is large. In addition, even if the sealing material 1a is attached to the adherend and exposed to a high-temperature environment for a long period of time, and then peeled off from the adherend, the sealing material 1a is less likely to break. Furthermore, since the foam 20 can be compressed and deformed to fit the gap, it is easy to obtain a seal structure that exhibits water-stopping properties using the sealing material 1a.

[0038] The structure of the foam 20 is not limited to a specific structure. The foam 20 has, for example, a closed cell structure. In this case, even if the seal material 1a is attached to an adherend and exposed to a high temperature environment for a long period of time, and then peeled off from the adherend, the seal material 1a is less likely to break. In addition, the liquid-tightness of the inside of the foam 20 is high, and the seal structure 2 is likely to exhibit the desired water-stopping property.

[0039] The foam 20 may have, for example, a semi-closed or semi-open cell structure. In this case, the foam 20 contains open cells before compression deformation, and when the foam 20 is compression deformed so that a compression strain of, for example, 50% or more occurs, the open parts are closed and the structure changes to a structure similar to that of closed cells. The foam 20 may have, for example, an open cell structure.

[0040] The material forming the foam 20 is not limited to a specific material. The foam 20 may be, for example, a rubber foam or a resin foam. Examples of the resin foam include urethane foam, silicone foam, and acrylic foam.

[0041] The foam 20 is preferably a rubber foam. In this case, the seal structure 2 is likely to exhibit high water stopping properties even when the compressive strain of the foam 20 in the seal structure 2 is small. The rubber foam is obtained, for example, by foaming a rubber composition containing a rubber, a foaming agent, and a crosslinking agent.

[0042] The rubber may be, for example, an olefin-based elastomer, a styrene-based elastomer, a butyl-based elastomer, a vinyl chloride-based elastomer, or a natural rubber. Examples of the olefin-based elastomer are ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM). Examples of the styrene-based elastomer are 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 the butyl-based elastomer are butyl rubber, polyisobutylene rubber, polybutene, polyisoprene rubber, and nitrile butadiene rubber (NBR). Examples of the vinyl chloride-based elastomer are chloroprene rubber and chlorosulfonated polyethylene rubber.

[0043] The rubber is preferably an olefin-based elastomer, and more preferably EPDM. In this case, even if the compression strain of the foam 20 in the seal structure 2 is small, the seal structure 2 is more likely to exhibit high water stopping properties.

[0044] 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 with a crosslinking agent.

[0045] Examples of dienes are 5-ethylidene-2-norbornene, 1,4-hexadiene, and dicyclopentadiene. These dienes may be used alone or in combination of two or more dienes. When the diene contains dicyclopentadiene, the degree of crosslinking can be improved.

[0046] 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 may be used. If the EPDM has long chain branches, the rubber composition can be foamed well.

[0047] The amount of dienes in the EPDM (diene content) is, for example, 1 mass% or more, desirably 2 mass% or more, and more desirably 3 mass% or more. The diene content is, for example, 20 mass% or less, desirably 15 mass% or less. This makes the rubber foam less susceptible to surface shrinkage and cracking.

[0048] The foaming agent may be an organic foaming agent or an inorganic foaming agent.

[0049] 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 are 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 are p-toluylenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide). Examples of fluorinated alkane-based blowing agents are 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 fine particles in which a thermally expandable substance is encapsulated in a microcapsule. Examples of such thermally expandable fine particles include commercially available products such as Microsphere (product name, manufactured by Matsumoto Yushi Co., Ltd.).

[0050] Examples of inorganic foaming agents are hydrogen carbonates, carbonates, nitrites, borohydrides, inorganic azides, and other known inorganic foaming agents. Examples of hydrogen carbonates are sodium hydrogen carbonate and ammonium hydrogen carbonate. Examples of carbonates are sodium carbonate and ammonium carbonate. Examples of nitrites are sodium nitrite and ammonium nitrite. Examples of borohydrides are sodium borohydride. These foaming agents may be used alone or in combination of two or more.

[0051] 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, based on 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.

[0052] Examples of crosslinking agents are 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, poly-p-dinitrosobenzene, polyamines, nitroso compounds such as p-dinitrosobenzene, organic peroxides, resins, and ammonium salts such as ammonium benzoate. Examples of organic peroxides are dicumyl peroxide, dimethyldi(t-butylperoxy)hexane, 1,1-di(t-butylperoxy)cyclohexane, and α,α'-di(t-butylperoxy)diisopropylbenzene. Examples of resins are alkylphenol-formaldehyde resins and melamine-formaldehyde condensates. These crosslinking agents may be used alone or in combination of two or more.

[0053] The crosslinking agent is preferably sulfur (S8) and a sulfur compound, a quinoid compound, or an organic peroxide. Sulfur (S8) and a sulfur compound are advantageous from the viewpoints of excellent mechanical strength and foaming properties. Quinoid compounds are advantageous from the viewpoints of reducing the sulfur atom content ratio, reducing corrosiveness, and excellent foaming properties. Organic peroxides are advantageous from the viewpoints of improving adhesion to the target object and step-following properties, etc., in order to realize a seal structure.

[0054] 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, relative to 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, relative to 100 parts by mass of rubber.

[0055] A quinoid compound and an organic peroxide may be used in combination as a crosslinking agent. In this case, crosslinking on the surface of the foam 20 is likely to be sufficiently performed. 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, and more desirably 10 parts by mass or more, relative to 100 parts by mass of the quinoid compound. The blending ratio is, for example, 100 parts by mass or less, and desirably 50 parts by mass or less, relative to 100 parts by mass of the quinoid compound.

[0056] The rubber composition desirably contains a foaming assistant and a crosslinking assistant. Examples of the foaming assistant include a urea-based foaming assistant, a salicylic acid-based foaming assistant, a benzoic acid-based foaming assistant, and a metal oxide such as zinc oxide. Preferred are a urea-based foaming assistant and a metal oxide. These foaming assistants may be used alone or in combination of two or more kinds.

[0057] The mixing ratio of the foaming aid is, for example, 0.5 parts by mass or more, and preferably 1 part by mass or more, relative to 100 parts by mass of rubber. The mixing ratio is, for example, 20 parts by mass or less, and more preferably 10 parts by mass or less, relative to 100 parts by mass of rubber.

[0058] Examples of the crosslinking assistants are 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 the crosslinking assistants. Examples of the thiazoles are dibenzothiazyl disulfide and 2-mercaptobenzothiazole. Examples of the thioureas are diethylthiourea, trimethylthiourea, and dibutylthiourea. Examples of the dithiocarbamic acids are sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, and zinc dibenzyldithiocarbamate. Examples of the guanidines are 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 isopropylxanthate and zinc isopropylxanthate. Examples of aldehyde ammonia are acetaldehyde ammonia and hexamethylenetetramine. Examples of aldehyde amines are n-butyraldehyde aniline and butyraldehyde monobutylamine.

[0059] The crosslinking aid may be an alcohol. Examples of the alcohol 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.

[0060] These cross-linking assistants may be used alone, or two or more kinds of cross-linking assistants may be used in combination.

[0061] When sulfur or a sulfur compound is used as the crosslinking agent, from the viewpoint of ensuring a good foam shape and flexibility of the foam 20, it is desirable to use thiazoles, thioureas, dithiocarbamic acids, or thiurams as the crosslinking assistant.

[0062] When a quinoid compound is used as a crosslinking agent, from the viewpoint of reducing corrosiveness, it is preferable to use an alcohol, more preferably a polyol, as a crosslinking assistant. In particular, when a p-quinone dioxime derivative is used as a quinoid compound, it is advantageous to use polyethylene glycol. When polyethylene glycol is used as a polyol, the rubber composition can be crosslinked well, and excellent foaming properties can be easily ensured.

[0063] The mixing ratio of the crosslinking aid is, for example, 0.01 parts by mass or more, preferably 0.02 parts by mass or more, and more preferably 0.06 parts by mass or more, relative to 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, relative to 100 parts by mass of rubber.

[0064] The rubber composition may contain additives such as lubricants (processing aids), pigments, fillers, flame retardants, and softeners, as necessary.

[0065] Examples of the lubricant 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, relative to 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, relative to 100 parts by mass of rubber.

[0066] 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, relative to 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, relative to 100 parts by mass of rubber.

[0067] The filler may be an inorganic filler, an organic filler, or any other known filler. Examples of inorganic fillers are 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, relative to 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, relative to 100 parts by mass of rubber.

[0068] Examples of the flame retardant are hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide. These flame retardants may be used alone, or two or more kinds 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, relative to 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, relative to 100 parts by mass of rubber.

[0069] Examples of the softener are petroleum oils, asphalts, low molecular weight polymers, organic acid esters, and tackifiers. Examples of the petroleum oils are paraffinic process oils such as paraffin oil, naphthenic process oils, drying oils or animal and vegetable oils, and aromatic process oils. An example of the drying oils or animal and vegetable oils is linseed oil. Examples of the organic acid esters are phthalates such as di-2-ethylhexyl phthalate (DOP) and dibutyl phthalate (DBP), phosphoric esters, higher fatty acid esters, and alkylsulfonic acid esters. As the softener, petroleum oils or asphalts are preferably used, 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 compounding ratio of the softener is, for example, 5 parts by mass or more, and preferably 10 parts by mass or more, per 100 parts by mass of rubber. The compounding ratio thereof is, for example, 300 parts by mass or less, and more desirably 200 parts by mass or less, relative to 100 parts by mass of rubber.

[0070] 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 of the rubber composition.

[0071] In the sealing material 1a, the surface portion 10e may or may not contain a filler. When the surface portion 10e contains a filler, the tack of the sealing material 1a can be easily adjusted to a desired range. The material of the filler is not limited to a specific material. The filler contains, for example, an inorganic substance. Examples of the inorganic substance are calcium carbonate, magnesium carbonate, clay, talc, mica, bentonite, silica, alumina, aluminum silicate, and aluminum.

[0072] 1, the sealing material 1a further includes, for example, an adhesive layer 10. The adhesive layer 10 is, for example, a pressure-sensitive adhesive layer. The adhesive layer 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.

[0073] Examples of thermoplastic elastomers are olefin-based elastomers, styrene-based elastomers, butyl-based elastomers, and vinyl chloride-based elastomers. Examples of olefin-based elastomers are ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM). Examples of styrene-based elastomers are 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 are butyl rubber, polyisobutylene rubber, polybutene, polyisoprene rubber, and nitrile butadiene rubber (NBR). Examples of vinyl chloride-based elastomers are chloroprene rubber or chlorosulfonated polyethylene rubber.

[0074] Examples of the thermosetting elastomer are silicone rubber, fluororubber, acrylic rubber, and polyamide rubber.

[0075] The rubber-based polymer is preferably a thermoplastic elastomer, more preferably a styrene-based elastomer or a butyl-based elastomer.

[0076] 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 million or less, preferably 3 million or less, and more preferably 1 million or less. In this case, the surface formed by the adhesive layer 10 is likely to have the desired adhesive strength. The weight average molecular weight is measured in polystyrene equivalent terms using gel permeation chromatography.

[0077] When the surface portion 10e contains a filler, the content of the filler in the adhesive layer 10 is not limited to a specific value. For example, the content of the filler in the adhesive layer 10 is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and more preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber-based polymer. The content of the filler 10f is, for example, 300 parts by mass or less, preferably 250 parts by mass or less, and more preferably 200 parts by mass or less, relative to 100 parts by mass of the rubber-based polymer. The adhesive layer 10 does not need to contain a filler.

[0078] The adhesive layer 10 desirably further contains a tackifier, which makes it easier for the end surface 11 formed by the adhesive layer 10 to have a desired adhesive strength, for example.

[0079] The tackifier is not limited to a specific substance. The tackifier is, for example, a specific resin. Examples of the resin are 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 are unmodified rosin, modified rosin, rosin phenol-based resins, and rosin ester-based resins. Examples of terpene-based tackifier resins are 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 are 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 resins. Examples of aromatic hydrocarbon resins are styrene-based resins and xylene-based resins. Examples of phenolic tackifying resins are alkylphenolic resins, xylene formaldehyde resins, resoles, and novolacs.The tackifier is preferably an alicyclic cyclic hydrocarbon or aromatic hydrocarbon resin.

[0080] The content of the tackifier in the adhesive layer 10 is not limited to a specific value. For example, the content of the tackifier in the adhesive layer 10 is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and more preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber-based polymer. The content of the tackifier is, for example, 200 parts by mass or less, preferably 100 parts by mass or less, and more preferably 80 parts by mass or less, relative to 100 parts by mass of the rubber-based polymer.

[0081] The thickness of the adhesive layer 10 is not limited to a specific value. The thickness is, for example, 50 to 400 μm. The thickness of the adhesive layer 10 may be 70 μm or more, or 80 μm or more. The thickness of the adhesive layer 10 may be 300 μm or less, or 250 μm or less.

[0082] 1, the sealing material 1a includes, for example, a pair of adhesive layers 10, and a foam 20 is disposed between the adhesive layers 10. In the sealing material 1a, the surface portion 10e may be formed only by the adhesive layer 10, or may be formed by the adhesive layer 10 and a part of the foam 20.

[0083] The sealing material 1a can be modified from various viewpoints. For example, the sealing material 1a may be modified to a sealing material 1b shown in FIG. 5. The sealing material 1b is configured in the same manner as the sealing material 1a, except for the parts that are particularly described. The components of the sealing material 1b that are the same as or correspond to the components of the sealing material 1a are given the same reference numerals, and detailed description will be omitted. The description of the sealing material 1a also applies to the sealing material 1b, unless there is a technical contradiction.

[0084] As shown in FIG. 5, the sealant 1b includes one adhesive layer 10 and a foam 20. The adhesive layer 10 forms one end face 11 in the thickness direction of the sealant 1b. The foam 20 forms the other end face 11 in the thickness direction of the sealant 1b. In the sealant 1b, a surface portion 10e including the adhesive layer 10 has a breaking strain of 500% or more and a tensile force F A [N / 20mm]>Adhesive force F BMeets the condition of [N / 20mm].

[0085] In the sealing material 1b, the tensile modulus of the foam 20 is not limited to a specific value. The tensile modulus of the foam 20 is, for example, 3 MPa or less. With this configuration, the sealing material 1b is disposed between the adherends in a compressed and deformed state, so that the gap between the end surface 11 formed by the foam 20 and the adherend is likely to be watertight. The tensile modulus of the foam 20 is preferably 2.5 MPa or less, and more preferably 2 MPa or less. The tensile modulus of the foam 20 is, for example, 0.5 MPa or more. EXAMPLES

[0086] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0087] <Example 1> SBS resin TR-2003 manufactured by ENEOS Materials and tackifier Alcon M-115 manufactured by Arakawa Chemical Industries Co., Ltd. were kneaded at a compounding ratio of 100 parts by mass and 35 parts by mass, respectively, to obtain a mixture. This mixture was hot-pressed under conditions of 150°C and 4 MPa to obtain an adhesive sheet according to Example 1 having a thickness of 100 μm. A laminate was obtained by disposing foam No. 6800 manufactured by Nitto Denko Corporation between two adhesive sheets according to Example 1. This foam was an EPDM foam having a closed cell structure and had a thickness of 10 mm. This laminate was heated in an oven at 140°C while applying a pressure of 2 kPa to bond the two adhesive sheets according to Example 1 and the foam. In this manner, a sealing material according to Example 1 was obtained.

[0088] <Examples 2 to 5> Sealing materials according to Examples 2 to 5 were obtained in the same manner as in Example 1, except for the following points. As the SBS resin, SBS resin D1155 manufactured by Kraton was used instead of TR-2003. The orientation ratios of the SBS resin and tackifier were adjusted as shown in Table 1A to obtain pressure-sensitive adhesive sheets according to Examples 2 to 5. The pressure-sensitive adhesive sheets according to Examples 2 to 5 were used instead of the pressure-sensitive adhesive sheet according to Example 1 to produce sealing materials according to Examples 2 to 5, respectively.

[0089] <Example 6> A sealing material according to Example 6 was obtained in the same manner as in Example 1, except for the following points. SBS resin TR-2003, tackifier Alcon M-115, and a filler which is heavy calcium carbonate manufactured by Maruo Calcium Co., Ltd. were kneaded in a mixing ratio of 100 parts by mass, 35 parts by mass, and 35 parts by mass, respectively, to obtain a mixture. This mixture was hot-pressed under conditions of 150°C and 4 MPa to obtain a pressure-sensitive adhesive sheet according to Example 6 having a thickness of 100 μm. A sealing material according to Example 6 was produced by using the pressure-sensitive adhesive sheet according to Example 6 instead of the pressure-sensitive adhesive sheet according to Example 1.

[0090] <Example 7> A sealing material according to Example 7 was obtained in the same manner as in Example 1, except for the following points. As the SBS resin, SBS resin Tufprene A manufactured by Asahi Kasei Corporation was used instead of TR-2003. Tufprene is a registered trademark. The thickness of the adhesive sheet was adjusted to 300 μm. The adhesive sheet according to Example 7 was used instead of the adhesive sheet according to Example 1 to produce a sealing material according to Example 7.

[0091] <Example 8> A sealing material according to Example 8 was obtained in the same manner as in Example 7, except for the following points. SBS resin Tufprene A, tackifier Alcon M-115, and a filler which is heavy calcium carbonate manufactured by Maruo Calcium Co., Ltd. were kneaded in a mixing ratio of 100 parts by mass, 45 parts by mass, and 35 parts by mass, respectively, to obtain a mixture. This mixture was hot-pressed under conditions of 150°C and 4 MPa to obtain a pressure-sensitive adhesive sheet according to Example 8 having a thickness of 300 μm. A sealing material according to Example 8 was produced by using the pressure-sensitive adhesive sheet according to Example 8 instead of the pressure-sensitive adhesive sheet according to Example 7.

[0092] <Example 9> A sealing material according to Example 9 was obtained in the same manner as in Example 4, except that foam EE-1000 manufactured by Nitto Denko Corporation was used instead of No. 6800. The foam EE-1000 was an EPDM foam and had an open cell structure. The thickness of the foam EE-1000 was 10 mm.

[0093] <Example 10> A sealing material of Example 10 was obtained in the same manner as in Example 4, except that one pressure-sensitive adhesive sheet of Example 4 was adhered to one surface of a foam.

[0094] <Example 11> A sealing material according to Example 11 was obtained in the same manner as in Example 4, except that Supersheet H, a polyurethane foam manufactured by NHK Spring Co., Ltd., was used as the foam instead of No. 6800. The thickness of Supersheet H was 10 mm.

[0095] <Example 12> A pressure-sensitive adhesive sheet according to Example 12 was obtained in the same manner as in Example 2, except that the orientation ratios of the SBS resin and tackifier were adjusted as shown in Table 1B. A sealing material according to Example 12 was produced in the same manner as in Example 1, except that the pressure-sensitive adhesive sheet according to Example 12 was used instead of the pressure-sensitive adhesive sheet according to Example 1.

[0096] <Example 13> A sealing material of Example 13 was obtained in the same manner as in Example 9, except that one pressure-sensitive adhesive sheet of Example 4 was adhered to one surface of a foam.

[0097] <Example 14> A sealing material of Example 14 was obtained in the same manner as in Example 13, except that the adhesive sheet of Example 12 was used instead of the adhesive sheet of Example 4.

[0098] <Example 15> A sealing material according to Example 15 was obtained in the same manner as in Example 1, except for the following points. SEBS resin G1657 manufactured by Kraton was used instead of TR-2003. The orientation ratios of the SEBS resin and tackifier were adjusted as shown in Table 1C to obtain a pressure-sensitive adhesive sheet according to Example 15. The pressure-sensitive adhesive sheet according to Example 15 was used instead of the pressure-sensitive adhesive sheet according to Example 1 to produce a sealing material according to Example 15.

[0099] <Example 16> Except for changing the thickness of the adhesive sheet to 200 μm, an adhesive sheet according to Example 16 was obtained in the same manner as in Example 15. The adhesive sheet according to Example 16 was used instead of the adhesive sheet according to Example 1 to produce a sealing material according to Example 16.

[0100] <Examples 17 and 18> Except for adjusting the orientation ratios of the SEBS resin and tackifier as shown in Table 1C, pressure-sensitive adhesive sheets according to Examples 17 and 18 were obtained in the same manner as in Example 16. Using the pressure-sensitive adhesive sheets according to Examples 17 and 18 instead of the pressure-sensitive adhesive sheet according to Example 16, sealing materials according to Examples 17 and 18 were produced, respectively.

[0101] <Example 19> Except for adjusting the orientation ratios of the SEBS resin and tackifier as shown in Table 1C and changing the thickness of the adhesive sheet to 300 μm, an adhesive sheet according to Example 19 was obtained in the same manner as in Example 16. The adhesive sheet according to Example 19 was used instead of the adhesive sheet according to Example 16 to produce a sealing material according to Example 19.

[0102] <Example 20> A sealing material of Example 20 was produced in the same manner as in Example 10, except that the adhesive sheet of Example 17 was used instead of the adhesive sheet of Example 4.

[0103] <Example 21> A sealing material of Example 21 was obtained in the same manner as in Example 13, except that the adhesive sheet of Example 17 was used instead of the adhesive sheet of Example 4.

[0104] <Example 22> A sealing material of Example 22 was obtained in the same manner as in Example 13, except that the adhesive sheet of Example 18 was used instead of the adhesive sheet of Example 4.

[0105] <Comparative Example 1> An acrylic double-sided pressure-sensitive adhesive sheet having a nonwoven fabric base was attached to both end faces in the thickness direction of foam No. 6800 having a thickness of 10 mm to obtain a sealing material according to Comparative Example 1. The thickness of this acrylic double-sided pressure-sensitive adhesive sheet was 120 μm.

[0106] <Comparative Example 2> Except for using a substrate-less acrylic double-sided adhesive sheet instead of the acrylic double-sided adhesive sheet, a sealing material according to Comparative Example 2 was obtained in the same manner as in Comparative Example 1. The thickness of this acrylic double-sided adhesive sheet was 40 μm.

[0107] <Comparative Example 3> A sealing material according to Comparative Example 3 was obtained in the same manner as in Example 2, except for the following points. The blending ratios of the SBS resin and tackifier in the preparation of the adhesive sheet were adjusted as shown in Table 2 to obtain an adhesive sheet according to Comparative Example 3. The adhesive sheet according to Comparative Example 3 was used instead of the adhesive sheet according to Example 2 to prepare a sealing material according to Comparative Example 3.

[0108] <Comparative Example 4> A sealing material according to Comparative Example 4 was obtained in the same manner as in Example 1, except that the production conditions for the adhesive sheet were adjusted so that the thickness of the adhesive sheet was 30 μm.

[0109] <Comparative Examples 5 and 6> Sealing materials according to Comparative Examples 5 and 6 were obtained in the same manner as in Example 8, except that the production conditions of the adhesive sheet were adjusted so that the thickness of the adhesive sheet was 100 μm and 200 μm, respectively.

[0110] <Comparative Example 7> A sealing material according to Comparative Example 7 was obtained in the same manner as in Example 6, except that in producing the adhesive sheet, the amount of filler added was changed to 160 parts by mass.

[0111] (Tensile test) A test piece was prepared by slicing a portion (surface portion) having a thickness of 300 μm including the adhesive sheet from the sealing material of each Example and Comparative Example, and a tensile test was performed. The test piece was a rectangle having a width of 10 mm and a length of 40 mm in a plan view. The tensile test was performed at room temperature, at a test speed of 1000 mm / min, and with a chuck distance of 10 mm. Other conditions of the tensile test were determined in accordance with JIS K6251. Tensile strength [MPa], tensile force F A , and breaking strain ε B [%] was calculated based on the following formulas (2), (3), and (4). The results are shown in Tables 1A, 1B, 1C, and 2. Tensile strength [MPa] = Maximum test force [N] / Cross-sectional area of ​​test piece [mm 2 ] Formula (2) Tensile force F A [N / 20mm] = 20mm × thickness of test piece [mm] × maximum test force [N] / cross-sectional area of ​​test piece [mm 2 ] Formula (3) Breaking strain ε B [%] = 100 × distance between chucks when test piece breaks [mm] / distance between chucks just before tensile test [mm] Formula (4)

[0112] Based on the results of the above tensile tests, a graph was created showing the tensile force F, determined by the following formula (5), as a function of strain [%]. Based on this graph, the average rate of change R AV The average rate of change R AV In determining the strain, the value used was not a value expressed as a percentage, but rather a value obtained by expressing the ratio of the deformation amount of the test piece to the original length, with the original length set to 1. For reference, equation (1) is shown again. In addition, from this graph, the specific strain ε CThe results are shown in Tables 1A, 1B, 1C, and 2. Tensile force F = 20 mm × thickness of test piece [mm] × test force [N] / cross-sectional area of ​​test piece [mm 2 ]Formula (5) R AV =(F 60 -F 40 ) / (ε b -ε a ) Formula (1)

[0113] Test pieces were prepared from the pressure-sensitive adhesive sheet of Example 4 and the foam used in Example 10, and a tensile test was carried out in the same manner as the above tensile test. The slope of the curve in the 5% to 25% range in the stress-strain curve obtained by the tensile test was determined as the tensile modulus of the end face. The tensile modulus of the end face in Example 10 is the tensile modulus of the end face formed by the foam.

[0114] (90° peel adhesion measurement) Test pieces were prepared using the sealing materials of each Example and Comparative Example. The test pieces were rectangular in shape with a length of 100 mm and a width of 20 mm in plan view. The test pieces were placed on a test plate made of SUS304 and having a thickness of 1.5 mm, and a 2 kg roller was moved back and forth once on the test piece to attach it. After attaching the test piece to the test plate, the test piece was stored together with the test plate in an oven maintained at 100°C for 7 days without applying a load to the test piece. Thereafter, the test piece was removed from the oven and allowed to cool at room temperature for 1 hour, and then the 90° peel adhesion strength F was measured in accordance with JIS Z 0237:2022. B The peeling speed was adjusted to 300 mm / min. The results are shown in Tables 1A, 1B, 1C, and 2.

[0115] (Evaluation of recyclability of sealing material) The sealing material according to each Example and Comparative Example was placed on a 1.5 mm thick plate made of SUS304, and a 2 kg roller was moved back and forth once on the sealing material to attach the sealing material to the plate. The test piece was stored together with the test plate in an oven maintained at 100°C for 7 days. After that, the test piece was removed from the oven and allowed to cool at room temperature for 1 hour, and then the surface of the sealing material was grasped by hand and peeled off from the plate at a speed of about 300 mm / min. In this case, the recoverability of the sealing material was evaluated according to the following criteria. The results are shown in Tables 1A, 1B, 1C, and 2. Good: The sealant was not broken and there was no adhesive remaining on the plate due to the sealant. Not enough: The sealant is broken and / or adhesive originating from the sealant remains on the plate material.

[0116] (Water-stopping evaluation) The sealing materials according to each embodiment and each comparative example were punched out into a circular ring having an inner diameter of 50 mm and an outer diameter of 70 mm to prepare a test piece for the IPX7 test. The test piece was placed between two acrylic plates, and a spacer was placed around the test piece between the two acrylic plates, and the test piece was fixed in a state in which a predetermined compressive strain was generated in the thickness direction of the acrylic plate. The acrylic plate was Acrylite EX manufactured by Mitsubishi Chemical Corporation and had a thickness of 10 mm. In this way, a sample for the IPX7 test was prepared. Acrylite is a registered trademark. The sample was submerged in a water tank filled with water to a height of 1 m, and after 30 minutes, the sample was taken out and the presence or absence of water leakage into the inside of the circular test piece was confirmed to determine whether it complies with the IPX7 standard. If there is no water leakage, it can be evaluated as complying with the IPX7 standard. The IPX7 test was performed by changing the compressive strain to determine the minimum compression ratio required to comply with the IPX7 standard. The results are shown in Tables 1A, 1B, 1C, and 2.

[0117] As shown in Tables 1A to 1C, the recyclability of the sealing materials according to the Examples was good. On the other hand, as shown in Table 2, the recyclability of the sealing materials according to the Comparative Examples was not good. By comparing the Examples and the Comparative Examples, the breaking strain ε Bis 500% or more and the tensile force F A >Adhesive force F B It is understood that the condition above is satisfied, so that the sealing material can be easily peeled off from the adherend after being exposed to a high-temperature environment for a long period of time. In Comparative Example 1, the breaking strain ε B In the comparative examples 2 to 7, the tensile force F A >Adhesive force F B The condition (a) was not met, and when the sealant was evaluated for recoverability, a part of the sealant remained on the plate material.

[0118] The first aspect of the present invention is A sealing material, The sealing material has a thickness of 1 to 40 mm, the sealing material has a surface portion including an end face in a thickness direction of the sealing material and having a thickness of 300 μm; The surface portion has a breaking strain of 500% or more, and Tensile force F A [N / 20mm]>Adhesive force F B Meets the condition of [N / 20mm], The tensile force F A is the maximum test force F in the tensile test performed on the test piece made from the surface portion 1 [N], the cross-sectional area S of the test piece 1 [mm 2 ], and the thickness t of the surface portion A F by [mm] 1 t A 20 / S 1 It is expressed as The test piece in the tensile test is rectangular in shape having a width of 10 mm and a length of 40 mm in a plan view, The chuck distance in the tensile test was 10 mm. The test speed in the tensile test was 1000 mm / min. The adhesive strength F Bis a 90° peel adhesion strength [N / 20 mm] measured by attaching a test piece made of the sealing material to a test plate, maintaining the environmental temperature of the test piece at 100°C for 7 days, and then peeling the test piece from the test plate in accordance with Japanese Industrial Standards (JIS) Z 0237:2022. A sealant is provided.

[0119] A second aspect of the present invention is The surface portion has an average rate of change of 1.5 [N / 20 mm] or more in the tensile test, The average rate of change is the ratio of the change in tensile force F [N / 20 mm] to the change in strain in the range of the test force ratio from 40% to 60% in the tensile test, The test force ratio is the maximum test force F 1 Test force F against [N] 2 is the ratio of [N], The tensile force F is the test force F 2 [N], the cross-sectional area S of the test piece 1 [mm 2 ], and the thickness t of the surface portion A F by [mm] 2 t A 20 / S 1 It is expressed as: A sealant according to a first aspect is provided.

[0120] A third aspect of the present invention is The surface portion exhibits a specific strain of 1800% or less in the tensile test, The specific strain is a strain corresponding to an intersection point between a first line and a second line in a graph showing the tensile force F [N / 20 mm] as a function of strain, the first straight line is a straight line passing through a pair of points on the graph where the strain ratios are 20% and 30%, the second straight line is a straight line passing through a pair of points on the graph where the strain ratio is 80% and 90%, The strain ratio is a ratio of the strain of the test piece to the breaking strain in the tensile test, The tensile force F is the test force F in the tensile test. 2 [N], the cross-sectional area S of the test piece 1 [mm 2 ], and the thickness t of the surface portion A F by [mm] 2 t A 20 / S 1 It is expressed as: A sealant relating to the first side or the second side is provided.

[0121] A fourth aspect of the present invention is The sealant comprises at least two layers. A sealing material relating to any one of the first to third sides is provided.

[0122] A fifth aspect of the present invention is The sealant comprises a foam. A sealing material relating to any one of the first to fourth side faces is provided.

[0123] A sixth aspect of the present invention is The foam has a closed cell structure. A sealant according to a fifth aspect is provided.

[0124] A seventh aspect of the present invention is The surface portion contains a filler. A sealing material relating to any one of the first to sixth sides is provided.

[0125] [Table 1A]

[0126] [Table 1B]

[0127] [Table 1C]

[0128] [Table 2] [Explanation of symbols]

[0129] 1a, 1b Sealing material 10e Surface section 11 End face 20. Foam t Thickness

Claims

1. A sealing material, The sealing material has a thickness of 1 to 40 mm; the sealing material has a surface portion including an end face in a thickness direction of the sealing material and having a thickness of 300 μm; The surface portion has a breaking strain of 500% or more, and Tensile force F A [N / 20mm]>Adhesive force F B [N / 20mm] condition is met, The tensile force F A is the maximum test force F in a tensile test performed on a test piece made from the surface portion 1 [N], the cross-sectional area S of the test piece 1 [mm 2 ], and the thickness t of the surface portion A [mm] by F 1 ・t A ・20 / S 1 It is expressed as The test piece in the tensile test is rectangular in shape having a width of 10 mm and a length of 40 mm in a plan view, The chuck distance in the tensile test was 10 mm. The test speed in the tensile test was 1000 mm / min. The adhesive strength F B is a 90° peel adhesive strength [N / 20 mm] measured by attaching a test piece made of the sealing material to a test plate, maintaining the environmental temperature of the test piece at 100° C. for 7 days, and then peeling the test piece from the test plate in accordance with Japanese Industrial Standards (JIS) Z 0237:2022. Sealing material.

2. The surface portion has an average rate of change of 1.5 [N / 20 mm] or more in the tensile test, The average rate of change is a ratio of a change in tensile force F [N / 20 mm] to a change in strain in a range of test force ratios from 40% to 60% in the tensile test, The test force ratio is the maximum test force F 1 Test force F against [N] 2 is the ratio of [N], The tensile force F is the test force F 2 [N], the cross-sectional area S of the test piece 1 [mm 2 ], and the thickness t of the surface portion A [mm] by F 2 ・t A ・20 / S 1 It is expressed as: The sealing material according to claim 1 .

3. The surface portion exhibits a specific strain of 1800% or less in the tensile test, The specific strain is a strain corresponding to an intersection point between a first line and a second line in a graph showing the tensile force F [N / 20 mm] as a function of strain, The first straight line is a straight line passing through a pair of points on the graph where the strain ratios are 20% and 30%, the second straight line is a straight line passing through a pair of points on the graph where the strain ratio is 80% and 90%, The strain ratio is a ratio of the strain of the test piece to the breaking strain in the tensile test, The tensile force F is the test force F in the tensile test. 2 [N], the cross-sectional area S of the test piece 1 [mm 2 ], and the thickness t of the surface portion A [mm] by F 2 ・t A ・20 / S 1 It is expressed as: The sealing material according to claim 1 .

4. The sealant comprises at least two layers. The sealing material according to claim 1 .

5. The sealant comprises a foam. The sealing material according to claim 1 .

6. The foam has a closed cell structure. The sealing material according to claim 5 .

7. The surface portion contains a filler. The sealing material according to claim 1 .

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