WO2019230680A1 - Adhesive agent composition, adhesive agent layer, and adhesive sheet - Google Patents

Abstract

The present invention relates to: an adhesive agent composition containing a base polymer and a water-absorbent material, and having a Young's modulus of 450 kPa or more when formed into an adhesive agent layer; an adhesive agent layer comprising the adhesive agent composition; and an adhesive sheet provided with the adhesive agent layer.

Description

Adhesive composition, adhesive layer and adhesive sheet

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition, and a pressure-sensitive adhesive sheet provided with the pressure-sensitive adhesive layer.

Conventionally, since it has both high initial adhesive strength and sufficient adhesive strength over time in adhesive bonding in various fields, moisture-curing pressure-sensitive adhesives and pressure-sensitive adhesive sheets using moisture-curing pressure-sensitive adhesives are known. Yes.

For example, Patent Document 1 discloses photopolymerization that can provide a moisture-curable adhesive having sufficient adhesive strength to an adherend having an uneven surface such as an inorganic material such as concrete or wood by photopolymerization. Composition and a moisture-curing adhesive sheet using the composition are described.

Japanese Unexamined Patent Publication No. 2000-273418

However, Patent Document 1 discusses the adhesive strength to an adherend having an uneven surface such as an inorganic material such as concrete or wood, but does not discuss the adhesive strength to a wet surface.
Further, when the conventional adhesive is bonded to the wet surface, there is a problem that the size changes due to swelling and the adhesive strength is lowered, and improvement of the adhesive force to the wet surface is required.

Accordingly, the present invention provides a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer that can be bonded to a wet surface while suppressing dimensional change due to swelling, a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition, and a pressure-sensitive adhesive comprising the pressure-sensitive adhesive layer. One issue is to provide a seat.

As a result of intensive investigations aimed at providing a pressure-sensitive adhesive layer and a pressure-sensitive adhesive sheet that can be bonded to a wet surface while suppressing dimensional change due to swelling, the present inventors have obtained a pressure-sensitive adhesive layer that absorbs moisture on the wet surface. It was conceived to use a pressure-sensitive adhesive composition containing a base polymer and a water-absorbing material. Furthermore, in order to suppress the dimensional change due to swelling and to obtain good adhesion to the wet surface, it was found that it is important to set the Young's modulus at the time of forming the pressure-sensitive adhesive layer in a specific range.

One embodiment of the present invention relates to a pressure-sensitive adhesive composition containing a base polymer and a water-absorbing material, and having a Young's modulus of 450 kPa or more when a pressure-sensitive adhesive layer is formed.

In one embodiment of the present invention, the water absorption when the pressure-sensitive adhesive layer is formed may be 2 to 10% by mass.

In one embodiment of the present invention, the base polymer preferably includes a rubber polymer or an acrylic polymer.

In one embodiment of the present invention, the water absorbing material is preferably a water absorbing polymer.

In one embodiment of the present invention, the content of the water-absorbing material with respect to 100 parts by mass of the base polymer is preferably 1 to 100 parts by mass.

One aspect of the present invention relates to an adhesive layer comprising the above-mentioned adhesive composition.

One aspect of the present invention relates to a pressure-sensitive adhesive sheet comprising the above pressure-sensitive adhesive layer.

In one embodiment of the present invention, the pressure-sensitive adhesive layer may be formed on a substrate.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can form the adhesive layer which can suppress the dimensional change by swelling and can adhere to a wet surface, the adhesive layer which consists of this adhesive composition, and an adhesive provided with this adhesive layer Sheets can be provided.

FIG. 1 is an example of a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention. FIG. 2 is an example of a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to the embodiment of the present invention. FIG. 3 is an example of a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

The pressure-sensitive adhesive composition according to the embodiment of the present invention is a pressure-sensitive adhesive composition containing a base polymer and a water-absorbing material, and has a Young's modulus of 450 kPa or more when a pressure-sensitive adhesive layer is formed.
Here, in the present specification, the term “adhesive sheet” may include those referred to as “adhesive tape”, “adhesive label”, “adhesive film” and the like.
In addition, the “adhesive surface” is a surface (applied surface) on the side that is attached to the adherend in the adhesive sheet. As for the adhesive sheet of this invention, only one side may be an adhesive surface and both surfaces may be an adhesive surface.

In the pressure-sensitive adhesive composition of this embodiment, the Young's modulus of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is formed is 450 kPa or more. The Young's modulus is preferably 500 kPa or more, and more preferably 600 kPa or more. If the Young's modulus is 450 kPa or more, good followability can be exhibited even for an adherend having an uneven surface. The upper limit of the Young's modulus is not particularly limited, but is preferably 10 MPa or less, more preferably 1000 kPa or less, further preferably 900 kPa or less, and particularly preferably 800 kPa or less. . When the Young's modulus is 10 MPa or less, the pressure-sensitive adhesive layer can be formed satisfactorily and the followability with the adherend is excellent. Moreover, even when it is affixed to the wet surface of the adherend, it can adhere to the wet surface while suppressing dimensional changes due to swelling.
The Young's modulus in this embodiment is a value at 25 ° C.
The Young's modulus of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is formed can be within the above range by adjusting the types and blending ratios of the base polymer and the water-absorbing material.

Here, the Young's modulus of the pressure-sensitive adhesive layer when forming the pressure-sensitive adhesive layer was determined by preparing a sample in which the pressure-sensitive adhesive layer was formed in a string shape, and using a tensile tester (AG-IS manufactured by Shimadzu Corporation). And can be calculated from a stress-strain curve measured when pulled at a speed of 50 mm / min.

Moreover, it is preferable that the water absorption rate when the adhesive composition in this embodiment forms an adhesive layer is 0.5 mass% or more. In addition, if it is 10% by mass or less, moisture hardly accumulates in the pressure-sensitive adhesive layer. As a result, swelling of the pressure-sensitive adhesive layer due to contact with moisture or moisture is suppressed, and the Young's modulus is easily set within a specific range, and dimensional change It becomes easy to obtain sufficient adhesive force on the wet surface. The water absorption rate is preferably 10% by mass or less, and more preferably 5% by mass or less. More preferably, it is 1 mass% or more, More preferably, it is 2 mass% or more, More preferably, it is 3 mass% or more. The pressure-sensitive adhesive composition in this embodiment particularly preferably has a water absorption rate of 2 to 10% by mass when the pressure-sensitive adhesive layer is formed. When the water absorption is 2% by mass or more, moisture on the surface of the adherend can be absorbed and removed, and good adhesive force can be easily obtained on the wet surface.
The water absorption rate can be calculated from the ratio of the mass of the pressure-sensitive adhesive layer after being immersed (stored) for 120 hours in pure water at 25 ° C. to the mass of the pressure-sensitive adhesive layer before being immersed. For example, the produced pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer) is cut into a sample having a width of 50 mm and a length of 50 mm. The prepared sample is stored in pure water at 25 ° C. for 120 hours, and the water absorption rate can be calculated from the mass change by the following formula.
Water absorption (mass%) = [(total mass of sample after 120 hours storage in water−total mass of sample before storage in water) / total mass of sample before storage in water)] × 100

The pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition in this embodiment preferably has a dimensional change rate of 3% or less after immersion (storage) of the pressure-sensitive adhesive layer in pure water at 25 ° C. for 24 hours. If the dimensional change rate is 3% or less, the adhesive layer swells due to contact with moisture or moisture, and the adhesive force decreases even when it is attached to the wet surface of the adherend. It becomes easy to prevent or suppress.

The dimensional change rate is more preferably 2% or less. In addition, the one where the said dimensional change rate is lower is preferable, and the lower limit is not specifically limited, For example, it is 1%.
The dimensional change rate can be calculated by the following formula from the thickness of the pressure-sensitive adhesive layer after being immersed and stored in pure water at 25 ° C. for 24 hours and the thickness of the pressure-sensitive adhesive layer before being immersed and stored. For example, a sample prepared by lining an adhesive layer with an aluminum foil is stored in pure water at 25 ° C. for 24 hours, the thickness of the adhesive layer before and after immersion is measured, and can be calculated by the following formula. Moreover, the thickness of an adhesive layer can be measured by the method as described in an Example.
Dimensional change rate (%) = [(thickness of pressure-sensitive adhesive layer after storage in water−thickness of pressure-sensitive adhesive layer before storage in water) / thickness of pressure-sensitive adhesive layer before storage in water] × 100

It does not specifically limit as a base polymer which comprises the adhesive composition in this embodiment, It is possible to use the well-known polymer used for an adhesive. Examples thereof include acrylic polymers, rubber polymers, vinyl alkyl ether polymers, silicone polymers, polyester polymers, polyamide polymers, urethane polymers, fluorine polymers, and epoxy polymers. Among the polymers exemplified above, acrylic polymers and rubber polymers are preferable from the viewpoint of adhesion, and rubber polymers are more preferable from the viewpoint of hydrophobicity.
Moisture on the wet surface that hinders adhesion between the pressure-sensitive adhesive sheet and the adherend when the pressure-sensitive adhesive layer is made hydrophobic by containing a hydrophobic polymer and the pressure-sensitive adhesive sheet is attached to the wet surface of the adherend. Is effective in removing water from the interface between the adherend and the pressure-sensitive adhesive layer. As a result, it becomes difficult for moisture to be taken into the pressure-sensitive adhesive layer, so that swelling of the pressure-sensitive adhesive layer is prevented, dimensional change is suppressed, and good adhesive force is easily obtained on the wet surface.

In the present embodiment, examples of the rubber-based polymer include polyisobutylene (PIB), a copolymer of isobutylene and normal butylene, a copolymer of isobutylene and isoprene (for example, regular butyl rubber, chlorinated butyl rubber, brominated butyl rubber). Butyl rubbers such as partially crosslinked butyl rubber), isobutylene polymers such as vulcanizates thereof; styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), isoprene Rubber (IR), Styrene-butadiene-styrene block copolymer (SBS), Styrene-ethylene-propylene-styrene block copolymer (SEPS, SIS hydrogenated product), Styrene-ethylene-propylene block copolymer (SEP) ,styrene Hydrogenated product of isoprene block copolymer), styrene thermoplastic elastomer such as styrene block copolymer such as styrene-isobutylene-styrene block copolymer (SIBS), styrene-butadiene rubber (SBR); synthetic butyl rubber (IIR) , Recycled butyl rubber, butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), EPR (binary ethylene-propylene rubber), EPT (ternary ethylene-propylene rubber), acrylic rubber, urethane rubber, silicone rubber, etc. Can be mentioned. Of these, recycled butyl rubber, PIB, IIR, IR, SIS, and SIBS are preferred because of their low water absorption, and recycled butyl rubber is more preferred. In addition, these may be used individually by 1 type and may be used in combination of 2 or more type.
Examples of the polymer for the rubber modifier include aliphatic hydrocarbon resins such as 1,3-pentadiene polymers and polybutenes, dicyclopentadiene alicyclic hydrocarbon resins, petroleum softeners ( Low polar polymers such as paraffinic oils, naphthenic oils, and aromatic oils) may be used.

In the present embodiment, the acrylic polymer is a polymer having (meth) acrylic acid ester as a main monomer component, and has a (meth) acrylic acid alkyl ester (having a linear or branched alkyl group ( What contains (meth) acrylic-acid alkylester) as a main monomer component can be used suitably. Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth ) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate , Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic acid Isodecyl, undecyl (meth) acrylate, dodecyl (meth) acrylate (Meth) acrylic acid tridecyl, (meth) acrylic acid tetradecyl, (meth) acrylic acid pentadecyl, (meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, (meth) acrylic acid octadecyl, (meth) acrylic acid nonadecyl, ( Examples include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 20 carbon atoms such as eicosyl acrylate. Among these, (meth) acrylic acid alkyl esters having an alkyl group having 1 to 14 carbon atoms are preferred, and (meth) acrylic acid alkyl esters having an alkyl group having 2 to 10 carbon atoms are more preferred. The above “(meth) acrylic acid ester” represents “acrylic acid ester” and / or “methacrylic acid ester”, and the same applies to others.

Examples of (meth) acrylic acid esters other than the above (meth) acrylic acid alkyl esters include cycloaliphatic hydrocarbon groups such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate. (Meth) acrylic acid ester having aromatic hydrocarbon groups such as (meth) acrylic acid ester and phenyl (meth) acrylate.

The above (meth) acrylic acid esters can be used alone or in combination of two or more. Further, monomers other than acrylic monomers may be copolymerized with (meth) acrylic acid esters.

In the present embodiment, 80% by mass or more of the monomer component constituting the acrylic polymer is preferably (meth) acrylic acid alkyl ester, more preferably 90% by mass or more, and still more preferably 100%. % By mass. *

Examples of the polar group-containing monomer include carboxyl group-containing monomers such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid or anhydrides thereof (such as maleic anhydride); Hydroxyl-containing monomers such as hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate; acrylamide, methacrylamide, N, N-dimethyl Amide group-containing monomers such as (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide; aminoethyl (meth) acrylate, (meth) Dimethylaminoethyl acrylate, (meth) acrylic amino group-containing monomers such as t-butylaminoethyl; glycidyl group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth) acryloylmorpholine, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, etc. Heterocycle-containing vinyl monomers; (meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; sulfonic acid group-containing monomers such as sodium vinylsulfonate 2-hydroxyethyl acryloylfo Phosphoric acid group-containing monomers such as Feto; cyclohexyl maleimide, imide group-containing monomers such as isopropyl maleimide; 2-methacryloyl isocyanate group-containing monomers such as methacryloyloxyethyl isocyanate, and the like.

Examples of the polyfunctional monomer include hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, and (poly) propylene glycol di (meth). Acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methanetri ( Examples include meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate.

The content of the base polymer in the pressure-sensitive adhesive composition according to this embodiment is not particularly limited, but from the viewpoint of the initial adhesive force, that is, the pressure-sensitive adhesive composition as a whole, excluding the solvent. The total amount of components excluding the solvent of the agent composition is 100% by mass, preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 20% by mass or more. Further, the content of the base polymer is preferably 90% by mass or less, more preferably 80% by mass or less, and more preferably 70% by mass or less, with respect to the entire component excluding the solvent of the pressure-sensitive adhesive composition. Is more preferable.

The pressure-sensitive adhesive composition in the present embodiment contains a water-absorbing material. Here, the water-absorbing material represents a material that can absorb and retain moisture. When the pressure-sensitive adhesive composition contains a water-absorbing material, when the pressure-sensitive adhesive sheet is affixed to the wet surface of the adherend, the water-absorbing material removes moisture on the wet surface that hinders adhesion between the pressure-sensitive adhesive sheet and the adherend. By absorbing and holding, the initial adhesive force of the adhesive sheet to the adherend is improved. In addition, since the moisture on the wet surface of the adherend is absorbed and removed by the water-absorbing material, the pressure-sensitive adhesive sheet can follow the adherend having an uneven surface well. As a result, the adhesion to the wet surface can be improved more easily.

As the water-absorbing material, an organic water-absorbing material such as a water-absorbing polymer or an inorganic water-absorbing material can be used. Among these, it is preferable to use a water-absorbing polymer. In addition, a water absorbing material may be used individually by 1 type, and may be used in combination of 2 or more type.
Examples of the water-absorbing polymer include polyacrylic acids, water-soluble celluloses, polyvinyl alcohols, polyethylene oxides, starches, alginic acids, chitins, polysulfonic acids, polyhydroxymethacrylates, polyvinylpyrrolidones, polyacrylamides, Examples thereof include polyethyleneimines, polyallylamines, polyvinylamines, maleic anhydride-modified polymers, and copolymers of monomers constituting these. In addition, a water absorbing polymer may be used individually by 1 type, and may be used in combination of 2 or more type.

Among them, a polyacrylic acid sodium salt, a maleic anhydride and isobutylene copolymer is preferable, and a maleic anhydride and isobutylene copolymer is more preferable.

A commercially available product may be used as the water-absorbing polymer. Commercially available water-absorbing polymers include, for example, KC Flock (cellulose powder, manufactured by Nippon Paper Chemicals Co., Ltd.), Sunrose (carboxymethylcellulose, manufactured by Nippon Paper Chemicals Co., Ltd.), Aquaric CA (acrylic acid polymer partial sodium salt) Cross-linked product, Nippon Shokubai Co., Ltd.), Acryhope (acrylic acid polymer partial sodium salt cross-linked product, Nippon Shokubai Co., Ltd.), Sunwet (Polyacrylate cross-linked product, Sundia Polymer Co., Ltd.), Aqua Pearl Acrylate cross-linked product, manufactured by Sundia Polymer Co., Ltd., Aqua Keep (acrylic acid polymer partial sodium salt cross-linked product, manufactured by Sumitomo Seika Co., Ltd.), Aqua Coke (modified polyalkylene oxide, manufactured by Sumitomo Seika Co., Ltd.), KI gel (cross-linked product of isobutylene-maleic anhydride copolymer, It can be suitably used a formula company manufactured by Kuraray Co., Ltd. Trading Co., Ltd.), and the like.

Examples of inorganic water-absorbing materials include silica gel and inorganic polymers such as smecton SA manufactured by Kunimine Kogyo Co., Ltd.

In the pressure-sensitive adhesive composition in the present embodiment, the content of the water-absorbing material is not particularly limited, but the pressure-sensitive adhesive composition has a higher Young's modulus and better adhesion to the wet surface. 1 mass part or more is preferable with respect to 100 mass parts of base polymers, 20 mass parts or more is more preferable, 30 mass parts or more is further more preferable, and 50 mass parts or more is especially preferable. Moreover, from a viewpoint of suppressing the dimensional change by swelling, 200 mass parts or less are more preferable, 150 mass parts or less are more preferable, and 100 mass parts or less are especially preferable.

The pressure-sensitive adhesive composition according to the present embodiment may contain a tackifier (tackifier) for the purpose of adjusting the Young's modulus and giving a tack during initial adhesion. Examples of tackifiers include polybutenes, rosin resins, terpene resins, petroleum resins (for example, petroleum aliphatic hydrocarbon resins, petroleum aromatic hydrocarbon resins, petroleum aliphatic / aromatic copolymerization carbonization). Hydrogen resin, petroleum-based alicyclic hydrocarbon resin (hydrogenated aromatic hydrocarbon resin), asphalt, etc.), coumarone-based resin, and the like. In terms of compatibility with the base polymer, petroleum resins and rosin resins are preferable. A tackifier may be used alone or in combination of two or more.

From the viewpoint of lowering the Young's modulus, the content in the case where the tackifier is contained in the pressure-sensitive adhesive composition is preferably 10 parts by mass or more, and 15 parts by mass or more with respect to 100 parts by mass of the base polymer. More preferably, it is more preferably 20 parts by mass or more. Further, the content of the tackifier is preferably 200 parts by mass or less and 100 parts by mass or less with respect to 100 parts by mass of the base polymer from the viewpoint of giving the adhesive a suitable cohesive force. More preferred is 50 parts by mass or less.

In addition, the pressure-sensitive adhesive composition of the present embodiment includes a viscosity modifier, a release modifier, a plasticizer, a softener, a filler, a colorant (pigment, dye, etc.), and aging, as long as the effects of the present invention are not impaired. You may add further the additives normally added to an adhesive composition, such as an inhibitor, surfactant, a leveling agent, an antifoamer, and a light stabilizer.
Examples of the filler include inorganic fillers such as talc, titanium oxide, calcium oxide, magnesium oxide, zinc oxide, titanium oxide, calcium carbonate, carbon, silica, clay, mica, barium sulfate, whisker, and magnesium hydroxide. It is done.
The content of the filler is not particularly limited as long as the Young's modulus can be within a specific range, but from the viewpoint of rough surface adhesion, it is 750 parts by mass or less with respect to 100 parts by mass of the base polymer. Is preferably 600 parts by mass or less, and more preferably 550 parts by mass or less. Moreover, from a viewpoint of the process stability of an adhesive sheet and suppression of the deformation | transformation at the time of an adhesive storage, it is preferable that it is 50 mass parts or more, and it is more preferable that it is 150 mass parts or more.

Moreover, various common solvents can be used as the solvent (solvent) used in the pressure-sensitive adhesive composition. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The said solvent may be used individually or in combination of 2 or more types.

The pressure-sensitive adhesive layer of this embodiment is formed using the above pressure-sensitive adhesive composition. The forming method is not particularly limited, and a known method can be adopted, but it can be performed according to the following method for producing a pressure-sensitive adhesive sheet. In addition, the preferable range of each component amount with respect to 100 mass parts of base polymers in an adhesive layer is the same as the preferable range of each component amount with respect to 100 mass parts of base polymers in an adhesive composition.

The pressure-sensitive adhesive layer in the present embodiment is formed using the above pressure-sensitive adhesive composition. The forming method is not particularly limited, and a known method can be adopted. For example, it can apply | coat to the base material mentioned later using a well-known coating method, and can make it dry and can obtain as an adhesive sheet form. Moreover, after forming a pressure-sensitive adhesive layer on the surface by applying a pressure-sensitive adhesive composition to a surface having peelability and drying or curing, the pressure-sensitive adhesive layer is bonded to a non-peelable substrate and transferred. You may let them. The method for applying the adhesive composition to the substrate is not particularly limited. For example, a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, fountain die coater, closed An edge die coater or the like can be used.

In addition, the pressure-sensitive adhesive layer may be formed by applying the pressure-sensitive adhesive composition to a release sheet (or a sheet-like substrate having a release surface).

The thickness of the pressure-sensitive adhesive layer after drying is not particularly limited, but is preferably 5 to 1000 μm, preferably 10 to 500 μm from the viewpoint of exhibiting good followability to an adherend having an uneven surface. Is more preferable. The drying temperature can be, for example, 50 to 150 ° C.

The pressure-sensitive adhesive layer may be formed using a solvent-free coating method such as rolling or extrusion. In this case, the pressure-sensitive adhesive composition can be obtained as a kneaded product by heating and kneading. For the kneading, for example, a batch kneader such as a kneader, a Banbury mixer, a mixing roll, or a continuous kneader such as a twin-screw kneader is used. The heating temperature in the kneading can be set to 80 to 180 ° C., for example.
The pressure-sensitive adhesive composition obtained as described above can be heated, for example, by a molding apparatus such as an extruder, a calender roll, or a press (heat press) to form the pressure-sensitive adhesive layer 12 in a sheet form.

The pressure-sensitive adhesive sheet of this embodiment has the pressure-sensitive adhesive layer described above.
The pressure-sensitive adhesive sheet of the present embodiment may be a pressure-sensitive adhesive sheet with a substrate having a pressure-sensitive adhesive layer on one or both sides of a sheet-like substrate (support), and the pressure-sensitive adhesive layer is held on a release sheet. It may be a baseless adhesive sheet such as. The concept of the pressure-sensitive adhesive sheet herein may include what are called pressure-sensitive adhesive tapes, pressure-sensitive adhesive labels, pressure-sensitive adhesive films and the like.

The pressure-sensitive adhesive layer is typically formed continuously, but is not limited to such a form. For example, the pressure-sensitive adhesive layer is formed in a regular or random pattern such as a dot shape or a stripe shape. It may be. In addition, the pressure-sensitive adhesive sheet of the present embodiment may be in a roll shape or a single wafer shape. Or the adhesive sheet of the form processed into various shapes may be sufficient.

Examples of the material for forming the base material include polyolefin films such as polyethylene, polypropylene, and ethylene / propylene copolymers; polyester films such as polyethylene terephthalate; plastic films such as polyvinyl chloride; paper such as kraft paper and Japanese paper Kinds: Cloths such as cotton cloth and soft cloth; woven cloths such as polyester non-woven cloth and vinylon cloth woven cloth; metal foil. Moreover, the thickness of a base material is not specifically limited.

The plastic films may be non-stretched films or stretched (uniaxially stretched or biaxially stretched) films. The surface of the substrate on which the pressure-sensitive adhesive layer is provided may be subjected to a surface treatment such as application of a primer and corona discharge treatment.

In this embodiment, the adhesive sheet may be perforated to provide a through hole. In this way, when the pressure-sensitive adhesive sheet is attached to the adherend, the moisture on the wet surface of the adherend can escape to the back side of the pressure-sensitive adhesive sheet (opposite to the sticking surface) through the through hole. More moisture on the wet surface of the adherend can be removed.

In the pressure-sensitive adhesive sheet of this embodiment, the pressure-sensitive adhesive layer may be protected by a release liner (separator, release film) until use.

As the release liner, a conventional release paper or the like can be used, and is not particularly limited. For example, a substrate having a release treatment layer, a low adhesive substrate made of a fluoropolymer, and a low adhesive substrate made of a nonpolar polymer. Etc. can be used.
Examples of the substrate having a release treatment layer include plastic films and papers surface-treated with a release treatment agent such as silicone, long chain alkyl, fluorine, and molybdenum sulfide.
Examples of the fluorine-based polymer of a low-adhesive substrate made of a fluorine-based polymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, chloro Examples include fluoroethylene / vinylidene fluoride copolymers.
Examples of the nonpolar polymer of the low-adhesive substrate made of a nonpolar polymer include olefin resins (for example, polyethylene and polypropylene). The release liner can be formed by a known or common method. Further, the thickness of the release liner is not particularly limited.

The pressure-sensitive adhesive composition, pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet (pressure-sensitive adhesive composition etc.) according to this embodiment preferably reduce or block the influence of surrounding water (moisture and humidity). For example, the pressure-sensitive adhesive sheet of this embodiment may be packaged with an appropriate package. Examples of the material of the package include aluminum moisture-proof bags, but are not limited thereto. The atmosphere inside the package may be air, but may be replaced with an inert gas such as nitrogen or argon. Moreover, you may bundle desiccants, such as a silica gel, in the inside of a package.

The adherend to which the pressure-sensitive adhesive sheet of the present invention is affixed is not particularly limited, and examples of the adherend include concrete, mortar, asphalt, metal, wood, tile, plastic material (for example, coating surface) Building exterior materials and interior materials such as interior walls of bathrooms, underwater and water surface structures such as ships and buoys, water tanks and bathtubs, sports equipment, etc.), fabrics such as woven fabrics and non-woven fabrics, paper, electrolyte membranes, separation membranes, filters And the like. Further, the adherend may be a living organism, and may be outside the living organism (for example, skin, outer shell, scales, etc.) or inside the living organism (for example, teeth or bones).

FIG. 1 is an example of a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention.
The pressure-sensitive adhesive sheet 10 of this embodiment includes a base material 11 and a pressure-sensitive adhesive layer 12, and the surface of the pressure-sensitive adhesive layer 12 opposite to the base material 11 is covered with a release liner 13 so as to be peeled off.
The pressure-sensitive adhesive sheet 10 of the present embodiment is used by peeling off the release liner 13 and being attached to an adherend via the pressure-sensitive adhesive layer 12. That is, in the pressure-sensitive adhesive layer 12 in the present embodiment, the surface on the release liner 13 side is a pressure-sensitive adhesive surface.

Hereinafter, the layer forming the pressure-sensitive adhesive sheet 10 of this embodiment will be described in detail.

The pressure-sensitive adhesive layer 12 in the present embodiment is made of a pressure-sensitive adhesive composition containing a base polymer and a water-absorbing material.

When the pressure-sensitive adhesive sheet 10 of the present embodiment is applied to the wet surface of the adherend, the adhesive layer removes the moisture existing on the wet surface of the adherend by removing moisture. Can be bonded.

The pressure-sensitive adhesive sheet according to the embodiment of the present invention may be provided with a pressure-sensitive adhesive layer on both surfaces of the substrate as shown in FIG. 2 and the pressure-sensitive adhesive layer may be protected with a release liner.
The pressure-sensitive adhesive sheet 30 of the present embodiment includes a first release liner 33A, a first pressure-sensitive adhesive layer 32A, a base material 31, a second pressure-sensitive adhesive layer 32B, and a second release liner 33B in this order.
The pressure-sensitive adhesive sheet 30 of the present embodiment peels and removes the first release liner 33A and the second release liner 33B, and makes the first pressure-sensitive adhesive layer 32A and the second pressure-sensitive adhesive layer 32B different from each other. Attached and used. That is, in this embodiment, both the first release liner 33A side surface of the first adhesive layer 32A and the second release liner 33B side surface of the second adhesive layer 32B are adhesive surfaces. is there.

The base material 31, the first and second pressure-sensitive adhesive layers 32A and 32B, and the first and second release liners 33A and 33B in the present embodiment are the same as the base material 11, the pressure-sensitive adhesive layer 12, and the release liner 13. is there.

Moreover, the pressure-sensitive adhesive sheet 30 in the present embodiment may be wound. That is, the pressure-sensitive adhesive sheet 30 of this embodiment does not include, for example, the second release liner 33B, and the pressure-sensitive adhesive surface of the second pressure-sensitive adhesive layer 32B is opposite to the first pressure-sensitive adhesive layer 32A of the first release liner 33A. It may be wound so as to be affixed to the side surface.

As shown in FIG. 3, the pressure-sensitive adhesive sheet according to the embodiment of the present invention may protect both surfaces of the pressure-sensitive adhesive layer with a release liner without providing a base material.
That is, the pressure-sensitive adhesive sheet 40 of the present embodiment may include the first release liner 43A, the pressure-sensitive adhesive layer 42, and the second release liner 43B in this order.
The pressure-sensitive adhesive sheet 40 of the present embodiment peels and removes the first release liner 43A and the second release liner 43B, and attaches one surface and the other surface of the pressure-sensitive adhesive layer 42 to different adherends. used. That is, in the present embodiment, the surface on the first release liner 43A side and the surface on the second release liner 43B side of the pressure-sensitive adhesive layer 42 are both adhesive surfaces.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

(Preparation of pressure-sensitive adhesive composition)
Example 1
100 parts by weight of recycled butyl rubber as a base polymer (product name S-Butyl Recycled Rubber, manufactured by Gogo Kogyo Co., Ltd.), 100 parts by weight of a petroleum-based resin (JXTG Energy Co., Ltd., T-Rez RB100) as a tackifier, 200 parts by mass of heavy calcium carbonate (made by Maruo Calcium Co., Ltd.) as a filler and 50 parts by mass of isobutylene / maleic anhydride copolymer (KI gel made by Kuraray Trading Co., Ltd.) as a water-absorbing material The pressure-sensitive adhesive composition of Example 1 was prepared.

(Example 2)
A pressure-sensitive adhesive composition of Example 2 was prepared in the same manner as in Example 1 except that the amount of heavy calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) used as a filler in Example 1 was changed to 300 parts by mass. .

(Example 3)
Example 3 is the same as Example 2 except that the amount of isobutylene / maleic anhydride copolymer (KI gel manufactured by Kuraray Trading Co., Ltd.) used as the water-absorbing material in Example 2 is changed to 20 parts by mass. A pressure-sensitive adhesive composition was prepared.

Example 4
In addition to 100 parts by mass of a petroleum-based resin (JXTG Energy Co., Ltd., T-Rez RB100) as a tackifier in Example 1, 10 parts by mass of modified asphalt (TRUMBLE BASE ASPHALT 4402 manufactured by OWENS CORNING Co., Ltd.) A pressure-sensitive adhesive composition of Example 4 was produced in the same manner as Example 1 except that the amount of heavy calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) used as the filler was changed to 500 parts by mass.

(Example 5)
A pressure-sensitive adhesive composition of Example 5 was produced in the same manner as in Example 4 except that the amount of modified asphalt used as a tackifier in Example 1 was changed to 30 parts by mass.

(Example 6)
A pressure-sensitive adhesive composition of Example 6 was produced in the same manner as in Example 1 except that the amount of heavy calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) used as a filler in Example 1 was changed to 500 parts by mass. .

(Example 7)
In the same manner as in Example 6 except that the amount of isobutylene / maleic anhydride copolymer (KI gel manufactured by Kuraray Trading Co., Ltd.) used as the water-absorbing material in Example 6 was changed to 100 parts by mass, The pressure-sensitive adhesive composition of Example 7 was produced.

(Comparative Example 1)
After dissolving 50 parts by mass of recycled butyl rubber (trade name: S-butyl recycled rubber, manufactured by Gogo Kogyo Co., Ltd.) and 50 parts by mass of liquid polybutene (HV-300, manufactured by JXTG Energy Co., Ltd.) in toluene as a base polymer. In this solution, 100 parts by mass of petroleum resin (JXTG Energy Co., Ltd., T-Rez RB100) as a tackifier and 100 parts by mass of heavy calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) as a filler are blended, A pressure-sensitive adhesive composition of Comparative Example 1 was produced.

(Comparative Example 2)
Further, a pressure-sensitive adhesive composition of Comparative Example 2 was prepared in the same manner as Comparative Example 1 except that 5 parts by mass of isobutylene / maleic anhydride copolymer (KI gel manufactured by Kuraray Trading Co., Ltd.) as a water-absorbing material was added. .

(Preparation of adhesive sheet)
Each material listed in Table 1 was put into a lab kneader mill (TD300-3 type manufactured by Toshin Co., Ltd.), heated to 140 ° C., and then kneaded for 30 minutes under the condition of a screw rotation speed of 40 rpm, and an adhesive mixture Was made.
A PET release liner (MRF38 (manufactured by Mitsubishi Chemical)) was used as a substrate, an adhesive mixture was placed on the release-treated surface, and a PET release liner (MRE38 (manufactured by Mitsubishi Chemical)) was coated thereon.
Then, the heat press was performed on conditions of 100 degreeC and 0.5 Mpa, and the adhesive sheet with an adhesive layer thickness of 1000 micrometers was produced.
Then, it bonded to the 55-micrometer-thick aluminum base material (product made from Toyo Aluminum), and produced the adhesive sheet which laminated | stacked the aluminum base material, the adhesive layer, and the PET peeling liner in this order.

(Measurement of water absorption)
A pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer) produced in the same manner as described above was cut to a width of 50 mm and a length of 50 mm to obtain a sample. The prepared sample was stored in pure water at 25 ° C. for 120 hours, and the water absorption was calculated from the mass change.
Water absorption (mass%) = [(total mass of sample after 120 hours storage in water−total mass of sample before storage in water) / total mass of sample before storage in water)] × 100
According to the obtained value, the water absorption rate of the pressure-sensitive adhesive layer was judged according to the following criteria.

(Evaluation criteria for water absorption)
Less than 2% by mass or more than 10% by mass: x (defect)
Over 5% by mass to 10% by mass: △ (somewhat poor)
2% to 5% by mass: ○ (good)

(Measurement of Young's modulus)
A sample (cross-sectional area 3 mm ² ) in which the pressure-sensitive adhesive layer was rolled into a string was prepared, and using a tensile tester (AG-IS manufactured by Shimadzu Corporation), temperature: 25 ° C., tensile speed: 50 mm / min, A tensile test was performed under the conditions of a distance between grippers: 10 mm and a load cell: 50N. From the stress-strain (SS) waveform (measurement chart), the tensile strength (N) and the average elongation (%) immediately before fracture were read, and the Young's modulus (kPa) was calculated from the SS waveform. Although the cross-sectional area changed in the swollen sample, it was evaluated as an apparent Young's modulus.

(Measurement of shear adhesive strength)
First, a slate standard plate manufactured by Nippon Test Panel Co., Ltd., having a product name “JIS A5430 (FB)” (hereinafter also referred to as a slate plate) having a thickness of 3 mm, a width of 30 mm, and a length of 125 mm was prepared. The glossy surface of this slate plate was used. This slate plate was dried at 130 ° C. for 1 hour, and the mass of the slate plate at this time was measured and defined as “the mass of the slate plate before being immersed in water”.
Subsequently, in a state where the prepared slate plate was immersed in water, it was deaerated with an ultrasonic deaerator (BRANSON 3510 manufactured by Yamato Scientific Co., Ltd.) for 1 hour, allowed to stand for 24 hours, and taken out from the water. The water of the slate plate was wiped off, and the mass of the slate plate at this time was measured and defined as “the mass of the slate plate after being immersed in water and deaerated”.
Based on the measured “mass of the slate plate before being immersed in water” and “mass of the slate plate after being immersed in water and degassed”, the water absorption rate of the slate plate was calculated from the following formula, 25% (mass% )Met.
Water absorption of slate plate (mass%) = [{(mass of slate plate after immersion in water, deaeration) − (mass of slate plate before immersion in water)} / (mass of slate plate before immersion in water) )] X 100

Next, the pressure-sensitive adhesive sheet produced in the same manner as above was cut to have a width of 20 mm and a length of 10 cm, and the release liner was peeled off.
Subsequently, on the surface (wet surface) of the slate plate from which water has been wiped off, the prepared adhesive sheet (test piece) was reciprocated once with a 2 kg roller and pasted, and in order to prevent the slate from drying, Each slate was covered with a wrap, and the entire surface was wrapped with aluminum foil and allowed to stand for 24 hours. Thereafter, the slate plate to which the pressure-sensitive adhesive sheet (test piece) is adhered is taken out, and using a tensile tester (digital force gauge AD4932A manufactured by A & D Co., Ltd.), the slate plate is peeled at 23 ° C. Shear adhesive strength (N / 20 mm) (adhesiveness vs. wet slate (2 kg roller press)) was measured.
According to the value of the obtained shear adhesive strength, the adhesiveness of the pressure-sensitive adhesive layer was judged according to the following criteria.

(Evaluation criteria for adhesiveness vs. wet slate (2kg roller press))
Less than 1N / 20mm: x (defect)
1N / 20mm or more: ○ (good)

Also, the state of the release surface of the pressure-sensitive adhesive layer was visually observed and evaluated. The adhesive layer can be peeled at the interface between the pressure-sensitive adhesive layer and the slate plate, and the surface where the peeled surface is not rough or the surface where the pressure-sensitive adhesive does not remain on the adherend is referred to as “interfacial peeling”. Those having irregularities on the surface or those in which the adhesive remained on the adherend were regarded as “cohesive failure”.

Next, the pressure-sensitive adhesive sheet produced in the same manner as above was cut to have a width of 20 mm and a length of 10 cm, and the release liner was peeled off.
Subsequently, the pressure-sensitive adhesive sheet (test piece) prepared in each example was pressure-bonded to the surface (wet surface) of the slate plate from which water had been wiped off at a load of 1 MPa for 5 minutes using a small vacuum heating press machine manufactured by Imoto Seisakusho Co., Ltd. In the same manner as above, the shear adhesive strength (N / 20 mm) (adhesiveness vs. wet slate (1 MPa pressure bonding)) at a peeling temperature of 23 ° C. with respect to the slate plate was measured, and the value of the obtained shear adhesive strength was obtained. Accordingly, the adhesiveness of the pressure-sensitive adhesive layer was judged according to the following criteria.
Further, the state of the release surface of the pressure-sensitive adhesive layer was visually observed in the same manner as described above.

(Evaluation criteria for adhesiveness vs. wet slate (1 MPa pressure bonding))
Less than 5N / 20mm: x (defect)
5N / 20mm or more: ○ (good)

(Measurement of dimensional change rate)
A sample prepared by cutting out the pressure-sensitive adhesive sheet obtained in the same manner as described above into 2 cm square was stored in pure water at 25 ° C. for 24 hours, and stored in water using Ozaki Seisakusho Co., Ltd. (Digital Gauge R1-205). The thickness of the pressure-sensitive adhesive layer was measured, and the dimensional change rate was calculated by the following formula.
Dimensional change rate (%) = [(thickness of pressure-sensitive adhesive layer after storage in water−thickness of pressure-sensitive adhesive layer before storage in water) / thickness of pressure-sensitive adhesive layer before storage in water] × 100

As shown in Table 1, the pressure-sensitive adhesive compositions and pressure-sensitive adhesive sheets of Examples 1 to 7 whose Young's modulus when forming the pressure-sensitive adhesive layer is within the prescribed range of the present invention suppresses dimensional change due to swelling and is moistened. It can be seen that it can adhere well to the surface.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications may be made to the above-described embodiments without departing from the scope of the present invention. And substitutions can be added.
This application is based on a Japanese patent application filed on May 29, 2018 (Japanese Patent Application No. 2018-102824) and a Japanese patent application filed on May 27, 2019 (Japanese Patent Application No. 2019-098482). The contents are incorporated by reference into this application.

10, 30, 40 Adhesive sheet 11, 31 Base material 12, 42 Adhesive layer 13 Release liner 32A First adhesive layer 32B Second adhesive layer 33A, 43A First release liner 33B, 43B Second release liner

Claims (8)

A pressure-sensitive adhesive composition containing a base polymer and a water-absorbing material,
The adhesive composition whose Young's modulus at the time of forming an adhesive layer is 450 kPa or more. The pressure-sensitive adhesive composition according to claim 1, which has a water absorption of 2 to 10% by mass when the pressure-sensitive adhesive layer is formed. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the base polymer includes a rubber polymer or an acrylic polymer. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the water-absorbing material is a water-absorbing polymer. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the content of the water-absorbing material with respect to 100 parts by mass of the base polymer is 1 to 100 parts by mass. A pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to any one of claims 1 to 5. A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer according to claim 6. The pressure-sensitive adhesive sheet according to claim 7, wherein the pressure-sensitive adhesive layer is formed on a substrate.

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