JP2002167557A - Composition for pressure-sensitive adhesive, pressure- sensitive adhesive and pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition for pressure-sensitive adhesives which excels in not only tackiness but also cohesive power and gives pressure-sensitive adhesives having excellent holding power after adhesion. SOLUTION: The composition for pressure-sensitive adhesives comprises 100 pts.wt. monomers having at least one alkyl (meth)acrylate having a 2-18C alkyl group as the major component and 0.1-100 pts.wt. phyllosilicate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure-sensitive adhesive composition capable of obtaining a pressure-sensitive adhesive exhibiting excellent cohesive strength, and to the pressure-sensitive adhesive and pressure-sensitive adhesive sheet.

[0002]

2. Description of the Related Art An adhesive is formed into a sheet having a predetermined thickness and is used for various applications as an adhesive tape. One of the basic properties required of an adhesive is to have strong adhesion to various adherends such as metal, plastic, wood or concrete. Another basic performance required is that it needs to be stably maintained after being attached to the adherend. After the pressure-sensitive adhesive tape is adhered to the adherend, any external force is applied to the pressure-sensitive adhesive tape.
The adhesive tape may be separated from the adherend and peeled off. In order to prevent such peeling, it is necessary to design the pressure-sensitive adhesive so as to increase the holding power of the pressure-sensitive adhesive tape.

[0003] Conventionally, as a method of increasing the holding power of an acrylic pressure-sensitive adhesive tape obtained by using an alkyl acrylate as a main component, when a pressure-sensitive adhesive composition is subjected to solution thermal polymerization to obtain a pressure-sensitive adhesive, the pressure-sensitive adhesive after the polymerization reaction is used. A method of adding and reacting an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent into the agent has been used.

[0004] When the pressure-sensitive adhesive composition is subjected to an ultraviolet polymerization reaction to obtain a pressure-sensitive adhesive, a polyfunctional acrylic monomer such as 1.6-hexanediol diacrylate is added to the pressure-sensitive adhesive composition, and the ultraviolet-ray polymerization is performed. It is known that a crosslinked structure can be obtained by the reaction, thereby increasing the holding power (for example, Adhesion Handbook, pages 144 to 14).
9 pages, published by Japan Adhesive Tape Industry Association).

[0005]

However, if a higher holding force is required in the above-mentioned pressure-sensitive adhesive tape, it is necessary to increase the amount of the crosslinking agent or polyfunctional acrylic monomer to increase the reaction ratio. is there. However, when the amount of the cross-linking agent or polyfunctional acrylic monomer added is increased to increase the reaction ratio, there is a disadvantage that the obtained adhesive becomes brittle.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide an acrylic adhesive which is excellent in cohesion and is not brittle in the finally obtained adhesive. The present invention relates to a composition for an adhesive, and an adhesive and an adhesive sheet obtained using the composition for an adhesive. In addition,
In the following description of the present specification, the term "pressure-sensitive adhesive sheet" includes the concepts of "pressure-sensitive adhesive tape" and "pressure-sensitive adhesive film".

[0007]

The composition for a pressure-sensitive adhesive according to the present invention comprises 100 parts by weight of a monomer comprising at least one alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms; Layered silicate 0.1-10
0 parts by weight, and by polymerizing the above-mentioned monomer, a pressure-sensitive adhesive excellent in cohesive strength and finally not brittle can be obtained.

In the present invention, the photopolymerization initiator is preferably used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the monomer.
Parts by weight, whereby by photopolymerization
An adhesive having excellent cohesion and not brittle can be obtained.

In the pressure-sensitive adhesive composition according to the present invention, preferably, the average interlayer distance of the (001) plane between the flaky crystals of the layered silicate measured by a wide-angle X-ray diffraction measurement method is 3 nm or more. is there.

As the layered silicate, montmorillonite and / or swellable mica is preferably used.
Since these have a large aspect ratio, the cohesive force is effectively increased.

[0011] Preferably, the layered silicate contains a metal ion as an exchangeable cation in the crystal structure, and the metal ion is ion-exchanged with another divalent metal ion or a cationic surfactant. Things are used.

As the cationic surfactant, a quaternary alkyl phosphonium salt having an alkyl group having 6 or more carbon atoms is preferably used, whereby the interlayer of the layered silicate can be sufficiently depolarized. The flaky crystals of the layered silicate can be easily peeled off, and the dispersibility of the flaky crystals of the layered silicate can be enhanced.

The pressure-sensitive adhesive according to the present invention comprises 100 parts by weight of a monomer containing at least one alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms, and a layered silicate 0 The composition is obtained by polymerizing a pressure-sensitive adhesive composition containing 0.1 to 100 parts by weight.

In the pressure-sensitive adhesive, preferably, the pressure-sensitive adhesive composition further contains 0.01 to 10 parts by weight of a photopolymerization initiator based on 100 parts by weight of the monomer, and the pressure-sensitive adhesive composition is light-sensitive. It is polymerized by polymerization.

The pressure-sensitive adhesive sheet according to the present invention is constituted by using the above-mentioned pressure-sensitive adhesive obtained according to the present invention. In this case, the above-mentioned pressure-sensitive adhesive composition is formed into a sheet, and then polymerized to form a pressure-sensitive adhesive. A sheet may be obtained, or a pressure-sensitive adhesive sheet may be obtained by molding the pressure-sensitive adhesive after obtaining the pressure-sensitive adhesive.

Hereinafter, the present invention will be described in detail. In the pressure-sensitive adhesive composition according to the present invention, the carbon number is 2 to 18;
Examples of the alkyl (meth) acrylate having an alkyl group include, for example, ethyl (meth) acrylate,
N-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, n- (meth) acrylate
-Octyl, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isomiristyl (meth) acrylate, ninol (meth) acrylate, isononyl (meth) acrylate, (meth) ) Isostearyl acrylate, stearyl (meth) acrylate and the like. These may be used alone or in combination of two or more.

In the pressure-sensitive adhesive composition according to the present invention, a polar monomer copolymerizable with the alkyl (meth) acrylate can be used in addition to the alkyl (meth) acrylate. Examples of usable polar monomers include carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid or anhydrides thereof, (meth) acrylonitrile, N
-Nitrogen-containing monomers such as vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropylacrylamide, 2-hydroxyethyl (meth) acrylate , 4-hydroxybutyl acrylate, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, caprolactone-modified (meth) acrylate and other hydroxyl-containing monomers, N-vinylformamide, N-vinylcarboxy such as N-vinylacetamide Acid amide and the like.

By using the above polar monomer in combination,
In the finally obtained pressure-sensitive adhesive or pressure-sensitive adhesive, a copolymer of the above alkyl (meth) acrylate and a polar monomer is constituted. The polar monomer may be used alone or in combination of two or more.

The content of the polar monomer is determined by the copolymer 10 with the alkyl (meth) acrylate.
It is desirable that the ratio be 2 to 30 parts by weight based on 0 parts by weight. When the content of the polar monomer is less than 2 parts by weight, the modulus of elasticity becomes too low, and a high shear strength may not be obtained. Conversely, if it exceeds 30 parts by weight, the modulus of elasticity becomes too high and the tackiness may be impaired.

In the composition for a pressure-sensitive adhesive according to the present invention, in addition to the alkyl (meth) acrylate and the polar monomer, another monomer copolymerizable therewith may be further added and copolymerized. Examples of such other monomers include vinyl acetate, vinyl propionate, styrene, isobornyl (meth) acrylate, and an olefin polymer having a polymerizable unsaturated double bond at a terminal. These other copolymerizable monomers may be appropriately added as needed.

Further, a crosslinked structure may be introduced into the polymer or copolymer obtained by polymerizing the above monomer component, if necessary, in order to increase heat resistance and creep property. As a cross-linking method, in solution polymerization in which polymerization is performed in a solvent or emulsion polymerization in which polymerization is performed in water,
There is a method in which a polymerizable monomer having a reactive polar group such as acrylic acid or hydroxyethyl (meth) acrylate is contained, and crosslinking is performed by adding a crosslinking agent capable of reacting with these polar groups.

Examples of the crosslinking agent include isocyanate-based crosslinking agents such as tolylene diisocyanate, naphthylene-1,5-diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, and trimethylolpropane-modified tolylene diisocyanate. Epoxy crosslinking agents such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether and 1,6-hexanediol diglycidyl ether; aziridine such as N, N-hexamethylene-1,6-bis (1-aziridinecarboxamide) And the like. These may be used alone or in combination of two or more.

When the above monomer components are subjected to bulk polymerization by photopolymerization, crosslinking can be carried out simultaneously with polymerization by adding a polyfunctional vinyl compound as a crosslinking agent.

Examples of the polyfunctional vinyl compound include 1,4-butanediol di (meth) acrylate,
1,6-hexanediol di (meth) acrylate,
1,9-nonanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate , Glycerin methacrylate acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy (meth)
Acrylates, polyester (meth) acrylates, urethane (meth) acrylates, and the like are listed, and these may be used alone or in combination of two or more.

When the amount of the crosslinking agent added is small, the cohesive force of the pressure-sensitive adhesive obtained by polymerizing the pressure-sensitive adhesive composition is reduced, and the heat resistance and creep properties may be reduced. If the amount of the agent is too large, the flexibility may be impaired and the adhesion to the adherend may be reduced. Therefore, the crosslinking agent is preferably added in the range of 0.01 to 5 parts by weight, more preferably 0.02 to 3 parts by weight, based on 100 parts by weight of the monomer component.

In the pressure-sensitive adhesive composition according to the present invention, the layered silicate is added in an amount of 0.1 to 100 parts by weight of the monomer component in order to increase the cohesive strength of the pressure-sensitive adhesive finally obtained.
It is blended at a ratio of 1 to 100 parts by weight. In the case where the above-mentioned polar monomer is used, 100 parts by weight of the monomer component refers to the total of the above-mentioned alkyl (meth) acrylate and the polar monomer.

The layered silicate is a silicate mineral having an exchangeable cation in a crystal structure (including an interlayer), and is not particularly limited. For example, montmorillonite, saponite, hectorite, beidellite , Stevensite, nontronite, and other smectite-based clay minerals, vermiculite, halloysite, and swellable mica. These layered silicates may be natural products or synthetic products.

[0028] Above all, montmorillonite and swellable mica having a large aspect ratio are preferably used, whereby the cohesive force of the finally obtained pressure-sensitive adhesive can be effectively increased.

The cation exchange capacity of the layered silicate having an exchangeable cation in the crystal structure is not particularly limited, but is preferably 50 to 200 meq / 100 g.
If the amount is less than 50 meq / 100 g, the amount of the cationic surfactant intercalated between the crystal layers by ion exchange becomes small, so that the interlayer may not be sufficiently depolarized. If it exceeds / 100 g, the bonding force between the layers of the layered silicate becomes strong, and the crystal flakes may be difficult to peel off.

Examples of the exchangeable cation include monovalent metal ions such as sodium and potassium, but other metal ions may be used. In the layered silicate used in the pressure-sensitive adhesive composition according to the present invention, preferably, the metal ion contained as the exchangeable cation is ion-exchanged with another divalent metal ion or a cationic surfactant.

As the other divalent metal ions in this case, it is desirable to use other appropriate divalent metal ions capable of increasing the acidity of the layered silicate before the ion exchange.
When the acidity of the layered silicate is increased, when the acrylic polymer or copolymer contains a polar monomer,
The dispersibility of the layered silicate is enhanced.

It is preferable that the ion exchange with the other divalent metal ions be performed. When the ion exchange is performed with a metal ion having more than two valences, the interlayer bonding force of the layered silicate becomes too strong, and the delamination (delamination) occurs. This is because lamination) does not easily proceed, and the dispersibility of the flaky crystal of the layered silicate decreases.

The other divalent metal ions are not particularly limited, but include, for example, metal ions such as nickel, magnesium and calcium, and the ion exchange improves the acidity of the layered silicate. The effect increases in the order of nickel, magnesium, and calcium.

It has been reported that the ion exchange with divalent metal ions such as nickel, magnesium and calcium improves the acidity of the hydroxyl groups of the crystalline flakes of the layered silicate. Among the above-mentioned divalent metal ions, nickel ions and magnesium ions are more preferable because the bonding force between crystal flakes during sintering is improved and a strong sintered film is easily formed.

In the present invention, the metal ion as the exchangeable cation may be ion-exchanged with a cationic surfactant as described above, and the cationic surfactant is not particularly limited. However, for example, quaternary ammonium salts and quaternary phosphonium salts are exemplified. These quaternary ammonium salts and quaternary phosphonium salts may be used alone or in combination.

The quaternary ammonium salt is not particularly restricted but includes, for example, lauryl trimethyl ammonium salt, stearyl trimethyl ammonium salt, trioctyl ammonium salt, distearyl dimethyl ammonium salt, distearyl dibenzyl ammonium salt and the like. And (co) polymers having a quaternary ammonium salt structure in the molecule. These quaternary ammonium salts may be used alone or in combination of two or more.

The (co) polymer having a quaternary ammonium salt structure in the molecule is not particularly limited. For example, a (co) polymer having an amino group, an alkylamino group, a dialkylamino group or the like in the molecule (meth) ) Acrylic monomer polymer or copolymer of the above (meth) acrylic monomer and styrene monomer such as styrene, α-methylstyrene, vinyltoluene, etc., is obtained by quaternary ammonium chloride with hydrochloric acid or the like. (Co) polymers. These (co) polymers having a quaternary ammonium salt structure in these molecules may be used alone or in combination of two or more.

The quaternary phosphonium salts include:
Although not particularly limited, for example, dodecyl triphenyl phosphonium salt, methyl triphenyl phosphonium salt, lauryl trimethyl phosphonium salt, stearyl trimethyl phosphonium salt, trioctyl phosphonium salt, distearyl dimethyl phosphonium salt, distearyl benzyl phosphonium salt and the like Is mentioned. These quaternary phosphonium salts may be used alone or in combination of two or more.

Of the above quaternary phosphonium salts, quaternary alkyl phosphonium salts having an alkyl group having 6 or more carbon atoms are preferably used. When the carbon number of the alkyl group is less than 6, the hydrophilicity of the alkylphosphonium ion becomes strong, and the interlayer of the layered silicate may not be sufficiently nonpolarized.

In the pressure-sensitive adhesive composition according to the present invention,
The layered silicate has an average interlayer distance of the (001) plane measured by a wide-angle X-ray diffraction measurement method of 3 nm or more;
In addition, it is preferable that the flaky crystals of the layered silicate exist in a state of being dispersed in five layers or less.

The average interlayer distance of the layered silicate is an average distance between flake crystals when fine flake crystals are formed into a layer, that is, an average interlayer distance. That is, it can be calculated by the wide-angle X-ray diffraction measurement method.

When the average interlayer distance of the layered silicate is 3 nm or more, the dispersibility of the flaky crystal can be enhanced, and the cohesive force in the finally obtained pressure-sensitive adhesive can be increased. The distance is 6 nm or more. That is, when the average interlayer distance of the layered silicate is 3 nm or more, the flaky crystals of the layered silicate are sufficiently separated, so-called frame separation stabilization is promoted, and the dispersibility is enhanced. Also, 6
Above nm, the interaction between the flaky crystals becomes so weak that it can be almost ignored. Therefore, the dispersibility of the flaky crystal in the flaky crystal acrylic polymer or copolymer constituting the layered silicate can be enhanced, and the cohesive force can be enhanced. In this case, when the flaky crystals are dispersed in five or less layers, the effect of improving the cohesive force by the layered silicate is enhanced. When dispersed in more than five layers, the flake-like crystal constituting the layered silicate may have a reduced stabilizing effect due to the layered state in the acrylic polymer or copolymer. .

The layered silicate used in the present invention is:
The layered silicate may be treated with a compound capable of chemically bonding to a hydroxyl group present on an end face of the layered silicate or containing a functional group having a chemical affinity with the hydroxyl group.

The functional group capable of forming a chemical bond with the above-mentioned hydroxyl group or having a chemical affinity is not particularly limited. Examples thereof include an alkoxy group, an epoxy group, a carboxyl group, a hydroxyl group, a maleic anhydride group and an isocyanate group. Functional groups having high chemical affinity with hydroxyl groups such as groups and aldehyde groups.

The compound capable of chemically bonding to a hydroxyl group or having a functional group having a chemical affinity is not particularly limited, and examples thereof include a silane compound, a titanate compound, and a glycidyl compound containing the above-mentioned various functional groups. Compounds, carboxylate salts, alcohols and the like can be mentioned, and among them, a silane compound is preferably used. These compounds may be used alone or in combination of two or more.

The silane compound is not particularly restricted but includes, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-aminopropyltrimethoxysilane, γ-amino Propylmethyldimethoxysilane, γ-aminopropyldimethylmethoxysilane, γ-
Aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyldimethylethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, N-β ( Aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyl Examples include trimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, and the like. These silane compounds may be used alone or in combination of two or more.

In the pressure-sensitive adhesive composition according to the present invention, the above-mentioned layered silicate is added in an amount of 0.1 to 100 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the above-mentioned monomer component. At a rate of If the amount of the layered silicate is less than 0.1 part by weight, the cohesive strength cannot be sufficiently increased, and if it exceeds 100 parts by weight, the adhesiveness is impaired.

In order to increase the adhesion of the acrylic polymer or copolymer component obtained by polymerization of the above monomer component to the adherend as an adhesive, a tackifier resin is added to the adhesive composition. It may be added.
Examples of the tackifying resin include, for example, rosin-based resins, modified rosin-based resins, terpene-based resins, terpene-phenol-based resins, C5 and C9-based petroleum resins, cumarone resins, and the like.
And hydrogenated products thereof. These may be used alone or in combination of two or more.

The addition amount of the tackifier resin is 5 to 70 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the acrylic copolymer component. If the addition amount is less than 5 parts by weight, the improvement in adhesion may be reduced, and
If the amount exceeds 0 parts by weight, the flexibility of the pressure-sensitive adhesive may decrease.

The composition for a pressure-sensitive adhesive according to the present invention may further comprise:
When the tackifier resin is added and the monomer component is polymerized by photopolymerization, a decrease in the polymerization rate or a decrease in the molecular weight may occur.In such a case, the amount of the chain transfer agent or the crosslinkable monomer may be reduced. Is preferably adjusted appropriately.
Examples of the tackifier resin having a low polymerization inhibiting property include a hydrogenated terpene resin, a hydrogenated rosin resin, a disproportionated rosin resin, a hydrogenated alicyclic hydrocarbon resin, and the like.

The pressure-sensitive adhesive composition according to the present invention and the pressure-sensitive adhesive obtained by polymerizing the pressure-sensitive adhesive composition may optionally contain various additives. Examples of the additives include a plasticizer, a softener, an inorganic filler (calcium carbonate, talc, aluminum, silica, fly ash, glass, etc.), an organic filler (polyolefin, urethane resin, acrylic resin, silicone resin, fluorine resin, etc.). Resin, etc.), pigments, dyes and the like. Further, as a filler, the volume of the pressure-sensitive adhesive may be increased by adding hollow fine particles having an average particle diameter of 5 to 200 μm, or by performing polymerization in a state where a gas is mixed with a copolymerization component before polymerization with stirring. .

The pressure-sensitive adhesive and the pressure-sensitive adhesive tape according to the present invention can be obtained by polymerizing the above monomer component of the pressure-sensitive adhesive composition according to the present invention. The polymerization method is not particularly limited, and a known appropriate polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, or pearl polymerization can be used. When performing solution polymerization, a thermal polymerization initiator such as azobisisobutyronitrile and benzoyl peroxide is used in the presence of a solvent such as ethyl acetate and toluene. In the case of bulk polymerization, photopolymerization using ultraviolet (UV) is preferred because a uniform polymer is easily obtained, and a photopolymerization initiator is used for photopolymerization.

Examples of the photopolymerization initiator include, for example, 4-
(2-Hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone [Darocur 2959: manufactured by Merck]; 2-hydroxy-2-methyl-1-phenyl-
Propan-1-one [Darocur 1173: manufactured by Merck]; methoxyacetophenone, 2,2-dimethoxy-
1,2-diphenylethan-1-one (Irgacure 6
51, manufactured by Ciba Specialty Chemicals); acetophenones such as 1-hydroxy-cyclohexyl phenyl ketone (Irgacure 184; manufactured by Ciba Specialty Chemicals); ketals such as benzyl dimethyl ketal; others; halogenated ketones and acyl phosphinoxides , Acylphosphonates and the like.

The amount of the photopolymerization initiator to be added is preferably in the range of 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the monomer component. If the amount of the photopolymerization initiator is less than 0.01 part by weight, the polymerization conversion rate is reduced, and only a polymer having a strong monomer odor may be obtained.If the amount exceeds 10 parts by weight, the amount of radical generation increases, In some cases, the molecular weight is reduced, and the necessary cohesive strength cannot be obtained.

As lamps used for light irradiation in photopolymerization, those having a light emission distribution at a wavelength of 420 nm or less are used. Examples thereof include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, and chemical lamps. , A black light lamp, a microwave excitation mercury lamp, a metal halide lamp, and the like. Among them, the chemical lamp efficiently emits light in the active wavelength region of the initiator, and because the composition other than the initiator absorbs less light, light is transmitted to the inside to produce a product having a high film thickness. It is preferable to do.

The intensity of light irradiation on the photopolymerizable composition by the lamp is a factor that affects the degree of polymerization of the obtained polymer, and is appropriately controlled for each performance of the target product.
When a conventional cleavage-type initiator having an acetophenone group is blended, the range is in a wavelength range effective for photodecomposition of the initiator (typically from 365 nm to 420 nm, depending on the initiator.
Of light is used. ) Is 0.1 to 100 mW /
cm ² is preferred.

The pressure-sensitive adhesive composition according to the present invention is directly used as a pressure-sensitive adhesive by polymerization. Alternatively, the pressure-sensitive adhesive sheet according to the present invention can be formed by forming a sheet shape before or after polymerization. In the case of the pressure-sensitive adhesive tape, a double-sided pressure-sensitive adhesive sheet having no base material may be used, or a base material obtained by forming a pressure-sensitive adhesive layer obtained by the pressure-sensitive adhesive composition according to the present invention on one or both surfaces of the base material. An adhesive sheet with a material may be used.

[0058]

(Example 1) Exchange of metal ions in layered silicate by transition metal complex 5 g of montmorillonite (trade name: Bengel A, manufactured by Toyshun Mining Co., Ltd.) and 495 g of distilled water are put into a beaker. Then, xylene was added to further expand the interlayer distance, and the mixture was stirred at room temperature for about 2 hours using a motor stirrer to prepare a swelling slurry of montmorillonite.

Next, 0.27 g of each of dicyclopentadienyltitanium dichloride and distearyldimethylammonium chloride was added to the swelling slurry, and the mixture was stirred at room temperature for 24 hours using a motor stirrer. To separate the solids. The operation of dispersing the solids in distilled water again and then separating the solids with a centrifugal separator was repeated twice more in order to remove unnecessary substances attached to the solids. The obtained solid was vacuum-dried at 50 ° C. for 48 hours using a vacuum dryer, and the obtained composition was used as a transition metal complex-containing organic layered silicate. The yield was 5.1 g. This organic phyllosilicate containing transition metal complex is hereinafter referred to as MMT-A.

Preparation of Adhesive Sheet 90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, and 0.1 part by weight of hexanediol diacrylate.
1 part by weight, 0.1 part by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name: Irgacure 651) and a tackifying resin (hydrogenated alicyclic hydrocarbon, manufactured by Arakawa Chemical Co., Ltd.)
(Trade name: KR1841A) 20 parts by weight of MMT-A prepared in above and 10 parts by weight of MMT-A are stirred in a separable flask until uniform, and then dissolved oxygen is removed by bubbling with nitrogen gas, and the present invention is concerned. A polymerizable monomer solution as a composition for an adhesive was prepared.

Next, a 0.5 m-thick polyethylene terephthalate (PET) film having a thickness of 50 μm was subjected to a release treatment.
After disposing a frame-shaped spacer having a thickness of m and spreading the polymerizable monomer solution in the frame, the PET film was bent and coated so that the release surface was in contact with the developed polymerizable monomer solution. In this state, the lamp intensity of the chemical lamp was adjusted so that the UV irradiation intensity on the PET film on the coating side was 10 mW / cm ^2, and irradiation with UV light was performed for 10 minutes. Thus, the pressure-sensitive adhesive sheet of Example 1 was obtained.

Example 2 Synthesis of Organic Layered Silicate Containing Transition Metal Complex / Alkyl Ammonium Salt 5 g of montmorillonite (manufactured by Toyshun Mining Co., Ltd., trade name: Wenger A) and 495 g of distilled water were charged into a beaker, and the interlayer distance was measured. Xylene was added to expand the mixture, and the mixture was stirred at room temperature for about 2 hours using a motor stirrer to prepare a swelling slurry of montmorillonite.

Next, 0.27 g of dicyclopentadienyl titanium dichloride was added to the swollen slurry,
The mixture was stirred at room temperature for 24 hours using a motor stirrer. Further, 2.88 g of distearyldimethylammonium chloride and 0.001 of concentrated hydrochloric acid were used as a cationic surfactant.
1 g was added to the swollen slurry, and the mixture was stirred at room temperature for 8 hours using a motor stirrer, and then the solid content was separated by a centrifugal separator. In order to remove unnecessary components attached to the solid components, the operation of dispersing the solid components in distilled water again and then separating the solid components with a centrifugal separator was repeated twice more. The obtained solid was vacuum-dried at 50 ° C. for 48 hours using a vacuum drier, and the obtained composition was used as a transition metal complex / alkyl ammonium salt-containing organic layered silicate. The yield was 8.01 g. The transition metal complex / alkyl ammonium salt-containing organic layered silicate is hereinafter referred to as MMT-B.

Preparation of pressure-sensitive adhesive sheet 75 parts by weight of 2-ethylhexyl acrylate and an olefin-based copolymer having a polymerizable unsaturated double bond at the end thereof (trade name: HPVM-L, manufactured by Clayton Polymer Japan Ltd.)
1253) 15 parts by weight, acrylic acid 10 parts by weight, hexanediol diacrylate 0.1 part by weight, and a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name:
Irgacure 651) 0.1 part by weight, and 20 parts by weight of a tackifier resin (hydrogenated alicyclic hydrocarbon, manufactured by Arakawa Chemical Co., Ltd., trade name: Alcon P-100) prepared by MMT-
After stirring with B10 parts by weight in a separable flask until it became uniform, dissolved oxygen was removed by bubbling with nitrogen gas to prepare a polymerizable monomer solution as a pressure-sensitive adhesive composition according to the present invention. Thereafter, in the same manner as in Example 1, an adhesive sheet was obtained by an ultraviolet polymerization method using the polymerizable monomer solution.

(Example 3) 75 parts by weight of 2-ethylhexyl acrylate and 15 parts by weight of an olefin copolymer having a polymerizable unsaturated double bond at the terminal (trade name: HPVM-L1253, manufactured by Clayton Polymer Japan) Parts, 10 parts by weight of acrylic acid, 0.1 part by weight of hexanediol diacrylate, and 0.1 part of a photopolymerization initiator (trade name: Irgacure 651 manufactured by Ciba Specialty Chemicals).
Parts by weight, 20 parts by weight of a tackifier resin (hydrogenated alicyclic hydrocarbon, manufactured by Arakawa Chemical Co., Ltd., trade name: Alcon P-100),
Distearyl dimethyl quaternary ammonium salt treated montmorillonite (manufactured by Toyshun Mining Co., trade name: New Esven D) 1
After stirring until the mixture became 0 parts by weight in a separable flask, the dissolved oxygen was removed by bubbling with nitrogen gas to prepare a polymerizable monomer solution as an adhesive composition. Hereinafter, in the same manner as in Example 1, an adhesive sheet was obtained by an ultraviolet polymerization method using the above polymerizable monomer solution.

Example 4 A 2% by weight aqueous solution of vinyltrimethoxysilane was stirred in a Henschel mixer with 500 g of montmorillonite treated with distearyl dimethyl quaternary ammonium salt (trade name: New Esven D, manufactured by Toyoshun Mining Co., Ltd.). 100 g was added dropwise over 3 minutes. After the addition, the mixture was further stirred for 10 minutes. The thus-obtained treated powder was stored in a vacuum dryer controlled at 70 ° C. and dried for 8 hours to obtain a dry powder. This powder is
-C.

90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.1 part by weight of hexanediol diacrylate and a photopolymerization initiator (trade name: Irgacure 651 manufactured by Ciba Specialty Chemicals)
0.1 parts by weight and a tackifier resin (hydrogenated alicyclic hydrocarbon,
Product name: Escolets 5300H, manufactured by Tonex
C) 20 parts by weight of the above-mentioned MMT-C and 10 parts by weight of the above MMT-C were stirred in a separable flask until uniform, and then dissolved oxygen was removed by bubbling with nitrogen gas to prepare a polymerizable monomer solution. Hereinafter, in the same manner as in Example 1,
The adhesive sheet of Example 4 was obtained by using an ultraviolet polymerization method.

(Example 5) 5 g of montmorillonite (manufactured by Toyshun Mining Co., Ltd., trade name: Wenger A) and 495 g of distilled water were put into a beaker, and about 2 g at room temperature using a motor stirrer.
After stirring for an hour, a swelled slurry of montmorillonite was prepared.

Next, 0.27 g of dodecyltriphenylphosphonium bromide was added to the swelled slurry, and the mixture was stirred at room temperature for 24 hours using a motor stirrer.
The solid was separated by a centrifuge. In order to remove unnecessary components attached to the solid components, the operation of dispersing the solid components in distilled water again and then separating the solid components with a centrifugal separator was repeated twice more. The obtained solid was vacuum-dried at 50 ° C. for 48 hours using a vacuum drier, and the obtained composition was used as a phosphonium salt-containing layered silicate. The yield was 5.1 g. This phosphonium salt-containing layered silicate is hereinafter referred to as MMT-D.

90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.1 part by weight of hexanediol diacrylate, and a photopolymerization initiator (trade name: Irgacure 651 manufactured by Ciba Specialty Chemicals)
0.1 parts by weight and a tackifier resin (hydrogenated alicyclic hydrocarbon,
Product name: Escolets 5300H, manufactured by Tonex
C) 20 parts by weight of the MMT-prepared as described above
After stirring with D10 parts by weight in a separable flask until the mixture became uniform, dissolved oxygen was removed by bubbling with nitrogen gas to prepare a polymerizable monomer solution. Thereafter, in the same manner as in Example 1, an adhesive sheet was obtained by an ultraviolet polymerization method using the above polymerizable monomer solution.

(Example 6) 5 g of montmorillonite (manufactured by Toyshun Mining Co., Ltd., trade name: Wenger A) and 495 g of distilled water were charged into a beaker, and about 2 mm at room temperature using a motor stirrer.
After stirring for an hour, a swelled slurry of montmorillonite was prepared.

Next, 0.7 g of nickel chloride was added to the above-mentioned swollen slurry, and the mixture was stirred at room temperature using a motor stirrer.
After stirring for an hour, the solid content was separated by a centrifugal separator. In order to remove unnecessary components attached to the solid components, the operation of dispersing the solid components in distilled water again and then separating the solid components with a centrifugal separator was repeated twice more.
The obtained solid was vacuum-dried at 50 ° C. for 48 hours using a vacuum dryer, and the obtained composition was used as a nickel ion-exchange layered silicate. The yield was 5.1 g. This nickel ion exchange layered silicate is hereinafter referred to as MMT-E.

90 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acrylic acid, 0.1 part by weight of hexanediol diacrylate, and a photopolymerization initiator (trade name: Irgacure 651 manufactured by Ciba Specialty Chemicals)
0.1 parts by weight and a tackifier resin (hydrogenated alicyclic hydrocarbon,
Product name: Escolets 5300H, manufactured by Tonex
C) 20 parts by weight of the MMT-prepared as described above
E10 parts by weight was stirred in a separable flask until it became uniform, followed by bubbling with nitrogen gas to remove dissolved oxygen, thereby preparing a polymerizable monomer solution. Thereafter, in the same manner as in Example 1, an adhesive sheet was obtained by an ultraviolet polymerization method using the above polymerizable monomer solution.

(Example 7) Purified montmorillonite (Kunimine Kogyo Co., trade name: Knipia F) as a layered silicate
An adhesive sheet was obtained in the same manner as in Example 1, except that 10 parts by weight was used.

(Comparative Example 1) An adhesive sheet was obtained in the same manner as in Example 1 except that no layered silicate was added.

(Comparative Example 2) An adhesive sheet was obtained in the same manner as in Example 2, except that no layered silicate was added.

(Evaluation of the performance of the pressure-sensitive adhesive sheets of Examples and Comparative Examples)
A 0 degree peel adhesion test, a shear adhesion test, and a JIS holding force test were performed. The results are shown in Table 1 below.

Average interlayer distance X-ray diffractometer (trade name: RINT11, manufactured by Rigaku Corporation)
00), the 2θ of the diffraction peak obtained by diffraction of the layered silicate layer in the evaluation sample was measured, and the (001) plane interval of the layered silicate was calculated by the following equation “Black diffraction equation”. did. D obtained from this equation was defined as the average interlayer distance. λ = 2 dsin θ (λ = 1.54, d: interplanar spacing of layered silicate, θ: diffraction angle)

90 ° Peel Adhesion Test The adhesive sheet sandwiched between PET films was cut into a width of 25 mm × length of 100 mm in an atmosphere of 23 ° C.
Under an atmosphere of 3 ° C., one of the PET films was peeled off to expose the adhesive surface, and the thickness was 2 mm, the width was 50 mm, and the length was 150.
mm polypropylene plate (manufactured by Nippon Test Panel)
The pressure-sensitive adhesive sheet was attached from the exposed pressure-sensitive adhesive surface side so as to have a bonding length of 100 mm. Next, the other PET film of the pressure-sensitive adhesive sheet was peeled off, a polyester film having a thickness of 25 μm was stuck on the exposed pressure-sensitive adhesive surface as a backing material, and weighing 2 kg from the back side of the backing material.
After being reciprocated two times with a roller, and left at 23 ° C. for 24 hours, a 90 ° peel adhesive force was measured at 23 ° C. using a tensile tester at a pulling speed of 300 mm / min.

Shear Adhesion Test The obtained pressure-sensitive adhesive sheet was cut into a width of 20 mm × 20 mm, and the thickness was 2 mm, the width was 50 mm, and the length was 1 at 23 ° C.
50mm polypropylene plate (manufactured by Japan Test Panel)
Were bonded together via a pressure-sensitive adhesive sheet from which PET films on both sides were peeled off, and pressed for 15 minutes under a load of 5 kg. After 24 hours, they were pulled in the shear direction at a pulling speed of 50 mm / min, and the shear adhesive force was measured. .

Holding Force Test The obtained pressure-sensitive adhesive sheet was cut into a width of 25 mm × 25 mm, and a thickness of 2 mm, a width of 50 mm, and a length of 1 were measured at 23 ° C.
50mm polypropylene plate (manufactured by Japan Test Panel)
Were bonded together via a pressure-sensitive adhesive sheet from which PET films on both sides were peeled off, and a test piece produced by press-fitting with a load of 5 kg for 15 minutes was left in a 23 ° C. atmosphere for 24 hours. After leaving the specimen in a constant temperature bath at 40 ° C. for 2 hours, a 1 kg weight was applied in the shearing direction, and the time until the weight dropped was measured.

[0082]

[Table 1]

[0083]

According to the composition for a pressure-sensitive adhesive according to the present invention, 100 parts by weight of a monomer containing at least one alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms is used. Layered silicate 0.1-100
Since the polymer contains the above parts by weight, by polymerizing the above monomer, it is possible to obtain a pressure-sensitive adhesive having excellent adhesiveness and exhibiting high cohesive strength. Therefore, it is possible to provide a pressure-sensitive adhesive having excellent holding power after being attached to an adherend.

Further, since the pressure-sensitive adhesive sheet according to the present invention is obtained by polymerizing the above-mentioned pressure-sensitive adhesive composition, the pressure-sensitive adhesive sheet not only has excellent adhesiveness to an adherend, but also exhibits a high cohesive force, and therefore has a high It is possible to provide an adhesive sheet having excellent holding power.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C09J 133/04 C09J 133/04 (72) Inventor Koji Taniguchi 2-1 Momoyama, Shimamotocho, Mishima-gun, Osaka Sekisui F-term (reference) in Chemical Industry Co., Ltd. FA141 HA316 HA356 JB08 JB09 KA42 LA06 PA23 PA32 QA01

Claims (7)

[Claims] 1. A composition comprising 100 parts by weight of a monomer comprising at least one alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms, and a layered silicate of 0.1 to 0.1 parts by weight.
100 parts by weight of the composition for an adhesive. 2. The pressure-sensitive adhesive composition according to claim 1, further comprising 0.01 to 10 parts by weight of a photopolymerization initiator based on 100 parts by weight of the monomer. 3. The pressure-sensitive adhesive composition according to claim 1, wherein an average interlayer distance of the (001) plane between the flaky crystals of the layered silicate measured by a wide-angle X-ray diffraction measurement method is 3 nm or more. object. 4. The pressure-sensitive adhesive composition according to claim 1, wherein the layered silicate is montmorillonite and / or swellable mica. 5. A layered silicate in which the layered silicate contains a metal ion as an exchangeable cation in a crystal structure, and the metal ion is ion-exchanged with another divalent metal ion or a cationic surfactant. The composition for an adhesive according to any one of claims 1 to 4, which is a salt. 6. An adhesive obtained by polymerizing the adhesive composition according to claim 1 or 2. 7. A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive according to claim 6.