Removable butyl rubber-based pressure-sensitive adhesive composition

Abstract

To provide a removable butyl rubber-based pressure-sensitive adhesive composition which has high tackiness and excellent resistance before crosslinking and has moderate tackiness and excellent removability after crosslinking.SOLUTION: According to the present invention, there is provided a removable butyl rubber-based pressure-sensitive adhesive composition containing 1 to 50 parts by mass of a dehydrating agent, 0.5 to 50 parts by mass of a crosslinking agent, and 40 to 300 parts by mass of an inorganic compound excluding the dehydrating agent and the crosslinking agent with respect to 100 parts by mass of a matrix polymer, in which the matrix polymer contains a butyl rubber and a halogenated butyl rubber, and a content ratio of the butyl rubber to the halogenated butyl rubber (butyl rubber: halogenated butyl rubber) is in a range of 10:90 to 90:10 in terms of a mass ratio.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a removable butyl rubber-based pressure-sensitive adhesive composition, more specifically to a removable butyl rubber-based pressure-sensitive adhesive composition used as a vacuum bag sealant material in autoclave molding, a typical molding method for aircraft structures. [Background technology]

[0002] Butyl rubber adhesives are used in a variety of bonding methods due to their high adhesiveness. Among these, techniques using resin crosslinking agents are known from the viewpoint of adhesiveness, which is a permanent adhesive type.

[0003] Patent Document 1 proposes a pressure-sensitive adhesive composition containing a polymer containing a predetermined amount of thermoplastic elastomer and halogenated rubber, and a resol-type phenolic resin crosslinking agent. Patent Document 2 also proposes a pressure-sensitive adhesive composition containing a rubber component containing 50 mass % or more of halogenated butyl rubber, an inorganic filler, a resin and a low-molecular-weight polymer, a vulcanization accelerator, and a crosslinking agent and a crosslinking aid.

[0004] Butyl rubber-based adhesives are also used as vacuum bag sealants in autoclave molding, a typical molding method for aircraft structures. Vacuum bag sealants are extruded rubber sealants with adhesive tape. These sealants are used to maintain airtightness inside the bag during autoclave molding, and are applied to metal or FRP molds to firmly hold (adhere) the vacuum bag film (Non-Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2012-012561 [Patent Document 2] Patent Publication No. 2006-169266 [Patent Document 3] Patent Publication No. 2007-238673 [Patent Document 4] Patent Publication No. 06-172590 [Non-patent literature]

[0006] [Non-Patent Document 1] Journal of the Japan Society for Composite Materials, 17, 1(1991), 15-23 Secondary materials - III. Molding auxiliary materials Summary of the Invention [Problem to be solved by the invention]

[0007] Sealing materials require strong adhesiveness and retention (creep resistance) to maintain airtightness, as well as moderate adhesiveness after the curing cycle is complete and removability that allows them to be easily removed from the mold without leaving any residue, which are contradictory properties. For these reasons, it has been difficult to apply conventional permanent adhesives.

[0008] For example, Patent Document 3 proposes a removable rubber composition that contains 1 to 30 parts by weight of an alkylphenol resin and 1 to 100 parts by weight of a molecular sieve per 100 parts by weight of rubber made of butyl rubber and / or EPDM, but has the problem of poor heat resistance.

[0009] Patent Document 4 proposes a rubber composition characterized by containing 100 parts by weight of a resin-crosslinkable raw rubber, 0.1 to 100 parts by weight of a resin crosslinking agent, and 0.1 to 200 parts by weight of a dehydrating agent. By blending the resin crosslinking agent and the dehydrating agent, heat resistance is improved, but there is a problem that the adhesiveness after crosslinking is too low, causing the rubber composition to peel off during processing.

[0010] An object of the present invention is to provide a removable butyl rubber-based pressure-sensitive adhesive composition that has high adhesion and excellent creep resistance before crosslinking, and that has moderate adhesion and excellent removability after crosslinking. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a removable butyl rubber-based pressure-sensitive adhesive composition that exhibits high adhesion and excellent creep resistance before crosslinking, and moderate adhesion and excellent removability after crosslinking. Because such a pressure-sensitive adhesive composition exhibits high adhesion and excellent creep resistance before crosslinking, it can firmly secure adherends such as molds and films to each other. Meanwhile, after crosslinking, it maintains moderate adhesion and exhibits excellent removability from adherends such as metal or FRP molds after use, thereby reducing residue.

[0012] The removable butyl rubber-based pressure-sensitive adhesive composition of the present invention can be used for various purposes as a removable pressure-sensitive adhesive, but more specifically, it can be suitably used as a vacuum bag sealant material in autoclave molding, a typical molding method for aircraft structures. [Means for solving the problem]

[0013] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by using a composition with a specific blend, which has led to the completion of the present invention.

[0014] That is, according to the present invention, the following inventions are provided. [1] A composition comprising, relative to 100 parts by mass of a matrix polymer, 1 to 50 parts by mass of a dehydrating agent, 0.5 to 50 parts by mass of a crosslinking agent, and 40 to 300 parts by mass of an inorganic compound other than the dehydrating agent and the crosslinking agent; A removable butyl rubber-based pressure-sensitive adhesive composition, wherein the matrix polymer contains butyl rubber and halogenated butyl rubber, and the content ratio of the butyl rubber to the halogenated butyl rubber (butyl rubber:halogenated butyl rubber) is in the range of 10:90 to 90:10 by mass. [2] The removable butyl rubber-based pressure-sensitive adhesive composition according to [1], wherein the halogenated butyl rubber comprises a chlorinated butyl rubber. [3] The removable butyl rubber pressure-sensitive adhesive composition according to [1] or [2], wherein the crosslinking agent contains an alkylphenol resin. [4] The removable butyl rubber pressure-sensitive adhesive composition according to any one of [1] to [3], wherein the dehydrating agent contains calcium oxide. [5] The removable butyl rubber pressure-sensitive adhesive composition according to any one of [1] to [4], which is used as a vacuum bag sealant material in autoclave molding. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B are diagrams illustrating a method for evaluating creep resistance, in which Fig. 1A shows the state at the start of the test, and Fig. 1B is a diagram illustrating the amount of displacement after being left standing. DETAILED DESCRIPTION OF THE INVENTION

[0016] Preferred embodiments for carrying out the present invention will be described below. Note that the embodiment described below is an example of a typical embodiment of the present invention, and the scope of the present invention should not be construed as being narrow.

[0017] [Removable butyl rubber adhesive composition] The removable butyl rubber pressure-sensitive adhesive composition of the present invention contains a matrix polymer, a dehydrating agent, a crosslinking agent, and inorganic compounds other than the dehydrating agent and the crosslinking agent. Each component will be described below.

[0018] <Matrix polymer> The removable butyl rubber pressure-sensitive adhesive composition of the present invention contains butyl rubber and halogenated butyl rubber. The mass ratio of the butyl rubber to the halogenated butyl rubber (butyl rubber:halogenated butyl rubber) is in the range of 10:90 to 90:10, preferably 30:70 to 70:30, and more preferably 40:60 to 60:40. By adjusting the mass ratio within this range, the adhesiveness after crosslinking is adequate, and the adhesive bond retention and removable properties are excellent, as well as creep resistance. The mass ratio may be 90:10, 85:15, 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, 50:50, 45:55, 40:60, 35:65, 30:70, 25:75, 20:80, 15:85, or 10:90. It may also be within a range between any two of the values ​​exemplified here.

[0019] In the present invention, butyl rubber refers to rubber containing a butyl polymer containing monomer units derived from isobutylene. That is, butyl rubber contains isobutylene monomer units. Furthermore, the butyl rubber according to one embodiment of the present invention may contain isobutylene monomer units and isoprene monomer units, i.e., it may include a copolymer obtained by copolymerizing raw material monomers containing isobutylene and isoprene. The butyl rubber may be, for example, partially crosslinked butyl rubber, reclaimed butyl rubber, or polyisobutylene. Note that, in the present invention, butyl rubber refers to non-halogenated butyl rubber that is (substantially) free of halogens such as chlorine and bromine and is not a halogenated butyl rubber. One or more types of butyl rubber may be used in combination.

[0020] Furthermore, halogenated butyl rubber is a rubber containing a butyl polymer containing a monomer unit derived from isobutylene, and contains a halogen such as chlorine or bromine. Halogenated butyl rubber can be obtained, for example, by halogenating the above-mentioned butyl rubber by a known method. Specifically, halogenation can be carried out by halogenating the moiety (monomer unit) derived from isoprene contained in the butyl rubber. Examples of halogenated butyl rubber include chlorinated butyl rubber and brominated butyl rubber. Halogenated butyl rubber can be used alone or in combination of two or more types.

[0021] The halogenated butyl rubber contains a halogen in an amount of preferably 0.1 to 5 mass %, more preferably 1 to 3 mass %.

[0022] In the weight ratio of butyl rubber to halogenated butyl rubber, if the weight ratio of butyl rubber is less than 10, the adhesive strength after vulcanization will be weak and the adhesiveness will be poor. Also, if the weight ratio of butyl rubber exceeds 90, the removability will be poor.

[0023] The removable butyl rubber-based pressure-sensitive adhesive composition according to the present invention may contain a rubber component other than butyl rubber or halogenated butyl rubber. Examples of rubber components other than butyl rubber or halogenated butyl rubber include liquid rubbers such as liquid polyisoprene, liquid polybutadiene, liquid polychloroprene, and liquid polybutene, natural rubber, isoprene rubber, butadiene rubber, 1,2-polybutadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, chlorinated polyethylene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber (EPDM), ethylene-vinyl acetate rubber, chloroprene rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, silicone rubber, fluororubber, urethane rubber, and styrene-based thermoplastic elastomers. These rubber components other than butyl rubber or halogenated butyl rubber may be used singly or in combination of two or more. Among rubber components other than butyl rubber and halogenated butyl rubber, liquid rubber is preferred, and is used in an amount of 5 to 100 parts by mass, preferably 10 to 80 parts by mass, and more preferably 20 to 60 parts by mass, per 100 parts by mass of the matrix polymer. By using a liquid rubber amount of 5 to 100 parts by mass, a good balance between the tackiness before crosslinking and the tackiness after crosslinking is achieved. The total content of the butyl rubber or halogenated butyl rubber in the matrix polymer is preferably 50% by mass or more, and more preferably 80% by mass or more, relative to 100% by mass of the matrix polymer. Specific examples of the total content of the butyl rubber or halogenated butyl rubber in the matrix polymer component include 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100% by mass, and may be within a range between any two of the values ​​exemplified here.

[0024] The removable butyl rubber pressure-sensitive adhesive composition preferably contains 20 to 60 mass %, more preferably 30 to 45 mass %, of a matrix polymer relative to 100 mass % of the removable butyl rubber pressure-sensitive adhesive composition. Specific examples of the matrix polymer content relative to 100 mass % of the removable butyl rubber pressure-sensitive adhesive composition include 20, 25, 30, 35, 40, 45, 50, 55, and 60 mass %, and may be within a range between any two of the values ​​exemplified here.

[0025] <Dehydrating agent> Heating in the crosslinking process turns the moisture contained in the material into water vapor, which generates bubbles in the crosslinked rubber, so in the present invention, a dehydrating agent is used to remove the moisture. The dehydrating agent is not particularly limited, but examples include calcium chloride, soda lime, silica gel, molecular sieves, deciclay, calcium oxide, etc. These dehydrating agents may be used alone or in combination of two or more.

[0026] The content of the dehydrating agent is 1 to 50 parts by mass, preferably 5 to 38 parts by mass, and more preferably 10 to 26 parts by mass, per 100 parts by mass of the matrix polymer. If the content is less than 1 part by mass, removability will be poor. If the content exceeds 50 parts by mass, adhesiveness after crosslinking will be poor. The content of the dehydrating agent is specifically, for example, 1, 5, 10, 15, 20, 25, 26, 30, 35, 38, 40, 45, or 50 parts by mass per 100 parts by mass of the matrix polymer, and may be within a range between any two of the values ​​exemplified here.

[0027] <Inorganic compounds excluding dehydrating agents and cross-linking agents> Examples of inorganic compounds other than the dehydrating agent and crosslinking agent used in the present invention include metal oxides such as alumina, aluminosilicate, zinc oxide, titanium oxide, magnesium oxide, iron oxide, tin oxide, antimony oxide, and ferrites; hydrated inorganic substances such as aluminum hydroxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and hydrotalcite; metal carbonates such as basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, strontium carbonate, and barium carbonate; calcium salts such as calcium sulfate and calcium silicate; glass beads, silica-based balloons, aluminum nitride, Examples of inorganic fibrous compounds include boron nitride, silicon nitride, carbon black, graphite, carbon balloons, various metal powders, potassium titanate, magnesium sulfate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, zinc borate, various magnetic powders, inorganic phosphorus compounds, glass fibers (E glass fiber, C glass fiber, S glass fiber, D glass fiber), rock wool, ceramic fibers (silica alumina fiber, alumina fiber, silica fiber), zirconia fiber, carbon fiber, bulk alkaline earth silicate fiber, gypsum fiber, carbon fiber, metal fiber, slag fiber, and basalt fiber. These inorganic compounds may be used alone or in combination of two or more.

[0028] The content of the inorganic compound excluding the dehydrating agent and the crosslinking agent is 40 to 300 parts by mass, preferably 70 to 250 parts by mass, and more preferably 110 to 250 parts by mass, per 100 parts by mass of the matrix polymer. If it is less than 40 parts by mass, creep resistance will be poor. If it exceeds 300 parts by mass, adhesion before crosslinking will be poor.

[0029] <Crosslinking agent> The crosslinking agent used in the present invention is not particularly limited as long as it is a crosslinking agent that can be used to crosslink butyl rubber, and examples thereof include organic peroxides, sulfur, zinc oxide, and alkylphenol resins. The crosslinking agent preferably includes an alkylphenol resin, more preferably an alkylphenol resin. The alkylphenol resin preferably includes at least one of a halogenated alkylphenol resin and a resole-type alkylphenol resin obtained by condensation of a phenol having an alkyl group containing 1 to 18 carbon atoms with formaldehyde, more preferably a halogenated alkylphenol resin or a resole-type alkylphenol resin obtained by condensation of a phenol having an alkyl group containing 1 to 18 carbon atoms with formaldehyde. The content of the alkylphenol resin relative to the total crosslinking agent may be 30% by mass or more, preferably 50% by mass or more, and more preferably 70% by mass or more. The content of the alkylphenol resin relative to the total crosslinking agent may be, for example, 30, 40, 50, 60, 70, 80, 90, or 100% by mass, and may be within a range between any two of the values ​​exemplified here. Examples of alkylphenol resins include alkylphenol-formaldehyde resins, brominated alkylphenol-formaldehyde resins, alkylphenol-sulfur chloride condensates, etc. The crosslinking agents may be used alone or in combination of two or more.

[0030] The content of the crosslinking agent is 0.5 to 50 parts by mass, preferably 1 to 35 parts by mass, and more preferably 3 to 20 parts by mass, per 100 parts by mass of the matrix polymer. If the content of the crosslinking agent is less than 0.5 parts by mass, crosslinking will be insufficient, resulting in poor adhesiveness after crosslinking. On the other hand, if the content of the crosslinking agent is more than 50 parts by mass, crosslinking will be excessive, resulting in poor adhesiveness after crosslinking. Specific examples include 0.5, 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 parts by mass, and may be within a range between any two of the values ​​exemplified here.

[0031] The removable butyl rubber pressure-sensitive adhesive composition of the present invention may contain additives such as softeners, tackifiers, antioxidants, crosslinking accelerators, lubricants, organic fibrous compounds, etc., which are used in ordinary rubber compositions, as long as the object of the present invention is not impaired.

[0032] <Softener> The softener refers to a substance that is liquid at room temperature, and examples thereof include paraffinic, naphthenic, aromatic process oil, rapeseed oil, phthalate esters, adipate esters, alkylsulfonate esters, sebacate esters, process oil, mineral oil, etc. These softeners may be used alone or in combination of two or more.

[0033] The content of the softener is preferably less than 200 parts by mass relative to 100 parts by mass of the matrix polymer. When the amount of the softener is less than 200 parts by mass, a good balance between pre-crosslinking tackiness and creep resistance is achieved.

[0034] [Characteristics of the composition] <Adhesive strength before crosslinking> The adhesive strength before crosslinking obtained based on the measurement method in the examples described later is preferably 5 N / 15 mm or more, more preferably 15 N / 15 mm or more, and even more preferably 25 N / 15 mm or more.

[0035] <Adhesive strength after crosslinking> The adhesive strength after crosslinking, measured by the method described later in the Examples, is preferably 0.5 N / 15 mm or more and less than 6 N / 15 mm, and more preferably 2.5 to 3.5 N / 15 mm.

[0036] [Adhesive tape] The removable butyl rubber-based pressure-sensitive adhesive composition according to the present invention can be suitably used as a vacuum back sealant material in autoclave molding, a typical molding method for aircraft structures. For example, the components contained in the butyl rubber-based pressure-sensitive adhesive composition can be kneaded using a kneading device or the like, and the kneaded mixture can be formed into a tape-like adhesive tape. In this case, the adhesive tape may have a substrate (prepared by applying the composition to both sides of the substrate), but it does not have to have a substrate.

[0037] The kneading device used when kneading the components is not particularly limited, and any known kneading device can be freely selected to perform the kneading. Examples of kneading devices include a Banbury mixer, a kneader mixer, and a two-roll mill. The method for forming the kneaded mixture into a tape is also not particularly limited, and any known forming method can be freely selected and used. Examples of such methods include molding methods such as roll molding and extrusion molding. [Example]

[0038] The present invention will be described in more detail below with reference to examples. Note that the examples described below are representative examples of the present invention and should not be construed as narrowing the scope of the present invention.

[0039] In the examples, "parts" are based on mass. Details of the materials used in the examples are shown below. <Matrix polymer> Butyl rubber: JSR Corporation "Butyl 268" Chlorinated butyl rubber: "Chlorobutyl 1066" manufactured by Japan Butyl Co., Ltd. Brominated butyl rubber: "Bromobutyl 2244" manufactured by Japan Butyl Co., Ltd. <Dehydrating agent> Calcium oxide: "VESTA-18" manufactured by Inoue Lime Industry Co., Ltd. Molecular sieve: Tomoe Engineering Co., Ltd. "Molecular sieve 3A" <Inorganic compounds excluding dehydrating agents> Calcium carbonate: "TA044" manufactured by Chichibu Lime Industry Co., Ltd. <Crosslinking agent> Alkylphenol-formaldehyde resin: "TACKIROLL201" manufactured by Taoka Chemical Co., Ltd. Brominated alkylphenol-formaldehyde resin: "TACKIROLL250-III" manufactured by Taoka Chemical Co., Ltd. Powdered sulfur (sulfur): manufactured by Hosoi Chemical Industry Co., Ltd.

[0040] [Preparation of removable butyl rubber pressure-sensitive adhesive composition] For each Example and Comparative Example, the components were mixed in the amounts shown in the table using a 3-liter kneader mixer at 110°C for 1 hour to obtain a kneaded product that was a butyl rubber pressure-sensitive adhesive composition. The resulting kneaded product was then processed into a tape shape with a width of 15 mm and a thickness of 2 mm using an extruder with a die temperature set to 70°C to produce an adhesive tape.

[0041] [Table 1]

[0042] [Table 2]

[0043] [Table 3]

[0044] [Table 4]

[0045] [evaluation] The adhesive properties were evaluated according to the following methods, and the results are shown in the tables. <Tackiness before crosslinking (adhesive strength before crosslinking)> A test piece was obtained by attaching a piece of adhesive tape (one side of which was lined with a 100 μm thick PET film) processed to a width of 15 mm, length of 100 mm, and thickness of 2 mm to a stainless steel plate (SUS304: 100 mm × 30 mm × 2.5 mm thick). This test piece was pressed back and forth with a 2 kg rubber roller. After leaving it for 20 minutes, the adhesive tape was peeled off in a 180° direction at a rate of 300 mm / min, and the adhesive strength was measured. The adhesiveness was evaluated according to the following criteria. Note that the higher the adhesive strength, the better the adhesiveness. ◎: Adhesive strength is 25N / 15mm or more ○: Adhesive strength is 15N / 15mm or more and less than 25N / 15mm △: Adhesive strength is 5N / 15mm or more and less than 15N / 15mm ×: Adhesive strength is less than 5N / 15mm

[0046] <Tackiness after crosslinking (adhesive strength after crosslinking)> A test piece was obtained by attaching a piece of adhesive tape (one side of which was lined with a 100 μm thick PET film) processed to a width of 15 mm, length of 100 mm, and thickness of 2 mm to a stainless steel plate (SUS304: 100 mm × 30 mm × 2.5 mm). This test piece was pressed back and forth with a 2 kg rubber roller and then left in an oven environment at 200 °C for 12 hours to crosslink. The test piece was removed from the oven and cooled at 21 °C for 24 hours. The adhesive strength was measured when the adhesive tape was peeled off in a 180° direction at a rate of 300 mm / min, and the adhesiveness was evaluated according to the following criteria. ◎: Adhesive strength is 2N / 15mm or more and less than 4N / 15mm ○: Adhesive strength is 1N / 15mm or more but less than 2N / 15mm, or 4N / 15mm or more but less than 5N / 15mm △: Adhesive strength is 0.5N / 15mm or more but less than 1N / 15mm, or 5N / 15mm or more but less than 6N / 15mm ×: Adhesive strength is less than 0.5N / 15mm or more than 6N / 15mm

[0047] <Removability (amount of adhesive residue)> After measuring the adhesive strength after crosslinking, the amount of adhesive residue on the stainless steel plate was visually determined according to the following criteria. The amount of adhesive residue is the area ratio of the adhesive tape and / or adhesive remaining on the stainless steel plate to the area of ​​the applied adhesive tape. The smaller the amount of adhesive residue, the better the removability. ◎: Adhesive residue is less than 10% ○: Adhesive residue is 10% or more and less than 20% △: Adhesive residue is 20% or more but less than 30% ×: Adhesive residue is 30% or more

[0048] <Creep resistance (shear force)> Two stainless steel plates (SUS304: 100mm x 30mm x 2.5mm thick) were bonded to a 15mm wide x 30mm long x 2mm thick adhesive tape (without a PET backing film). One of the plates was fixed in place, and a 200g weight was hung from the other plate (see Figure 1A). The plate was then left at 40°C for one hour. After one hour, the amount of slippage (the distance the plate slipped) relative to the other plate was measured (see Figure 1B), and creep resistance was evaluated according to the following criteria. Note that a smaller amount of slippage indicates better creep resistance. ◎: Misalignment is less than 2 mm ○: Misalignment is 2mm or more and less than 5mm △: Misalignment is 5mm or more and less than 8mm ×: Misalignment is 8mm or more

Claims

1. the composition contains, relative to 100 parts by mass of a matrix polymer, 1 to 50 parts by mass of a dehydrating agent, 0.5 to 50 parts by mass of a crosslinking agent, and 40 to 300 parts by mass of an inorganic compound other than the dehydrating agent and the crosslinking agent; a removable butyl rubber-based pressure-sensitive adhesive composition, wherein the matrix polymer contains butyl rubber and halogenated butyl rubber, and the content ratio of the butyl rubber to the halogenated butyl rubber (butyl rubber:halogenated butyl rubber) is in the range of 10:90 to 90:10 by mass ratio.

2. The removable butyl rubber-based pressure-sensitive adhesive composition according to claim 1 , wherein the halogenated butyl rubber comprises a chlorinated butyl rubber.

3. The removable butyl rubber pressure-sensitive adhesive composition according to claim 1 , wherein the crosslinking agent comprises an alkylphenol resin.

4. The removable butyl rubber pressure-sensitive adhesive composition according to claim 1 , wherein the dehydrating agent comprises calcium oxide.

5. The removable butyl rubber pressure-sensitive adhesive composition according to any one of claims 1 to 4, which is used as a vacuum bag sealant material in autoclave molding.

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