JP6681654B2 - Multilayer adhesive sheet - Google Patents

Description

  The present invention relates to a multilayer PSA sheet, and more particularly to a multilayer PSA sheet excellent in solvent resistance, surface slipperiness and curved surface conformability.

  For example, in the automobile and aircraft industries, a transparent adhesive sheet may be attached to prevent damage to the painted surface of the body of an automobile or the like. This pressure-sensitive adhesive sheet requires solvent resistance for use outdoors, and this pressure-sensitive adhesive sheet can be directly attached to the painted surface by hand using a squeegee, etc. There have been problems such as stains on hands, or inability to attach them neatly particularly on a site where a three-dimensional curved surface is severe. In addition, since the squeegee does not slide on the surface of the pressure-sensitive adhesive sheet, there are problems such as wrinkles and scratches on the pressure-sensitive adhesive sheet. Furthermore, with a protective pressure-sensitive adhesive sheet having a coating layer with good surface slipperiness, the followability deteriorates at the severe part of the three-dimensional curved surface, and it may be adhered to an adherend having a three-dimensional curved surface. There was a problem that made it difficult.

  Further, there is known a pressure-sensitive adhesive sheet in which a base material made of IPN is provided with a fluorine coating layer (see, for example, Japanese Patent Laid-Open No. 2001-520127), but it has curved surface followability with respect to an adherend having a complicated curved surface. Is also insufficient, and from the viewpoint of weather resistance and the like, a pressure-sensitive adhesive sheet for coating film protection in which a base material is provided with a coating layer made of a fluororesin (see, for example, JP-A-2009-299053) is also known. However, its flexibility was insufficient and it was difficult to apply it to complicated parts.

Japanese Patent Publication No. 2001-520127 JP, 2003-96140, A JP, 59-41376, A JP, 2005-272558, A JP, 2009-299053, A JP, 2011-100542, A

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a multilayer pressure-sensitive adhesive sheet having excellent solvent resistance, surface slipperiness, and curved surface followability.

  The multilayer pressure-sensitive adhesive sheet of the present invention is at least a multilayer pressure-sensitive adhesive sheet having a surface protective layer, a base material layer and a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer being provided on one surface of the base material layer, The surface protective layer is provided on the other surface of the base material layer, the surface protective layer contains an N, N-dimethylformamide (DMF) insoluble matter, and exceeds 0% of the multilayer pressure-sensitive adhesive sheet. The maximum stress value in a 10% stretched state is 0.5 MPa or more and 4.0 MPa or less.

  Here, the surface protective layer preferably contains 50% by weight or more of an N, N-dimethylformamide (DMF) insoluble matter.

  In the present invention, the surface protective layer preferably contains a urethane polymer as a main component.

  Here, the urethane polymer is preferably a water-based urethane polymer or a solvent-based urethane polymer.

  In the present invention, the surface protective layer preferably contains 5 parts by weight or more and 12 parts by weight or less of the crosslinking agent with respect to 100 parts by weight of the urethane polymer.

  In the present invention, the base material layer preferably contains at least a urethane polymer.

  Here, the base material layer is preferably a urethane-based polymer or a composite film containing a (meth) acrylic-based polymer and a urethane-based polymer.

  In the present invention, the multilayer pressure-sensitive adhesive sheet is preferably used as a protective sheet for protecting the surface of an adherend.

  According to the present invention, a multi-layer pressure-sensitive adhesive sheet having excellent solvent resistance, capable of being adhered cleanly even in a region where a three-dimensional curved surface has a curved surface following property, and has a good surface slip property. Can be realized.

It is a schematic diagram for explaining a method of measuring a coefficient of static friction. It is explanatory drawing for demonstrating the cross-section curve of a three-dimensional curved-surface site | part regarding evaluation of sticking workability.

Hereinafter, the present invention will be described in detail.
The multilayer pressure-sensitive adhesive sheet of the present invention is a laminated sheet having at least a pressure-sensitive adhesive layer, a base material layer, and a surface protective layer. However, the surface protective layer contains N, N-dimethylformamide (DMF) insoluble matter. The surface protective layer is preferably arranged on the outermost surface of the multilayer adhesive sheet.

  The surface protective layer preferably contains a urethane polymer as a main component, and for example, the base resin of the surface protective layer is preferably a urethane polymer. The urethane polymer is preferably a water-based urethane polymer or a solvent-based urethane polymer. The urethane polymer needs to be liquefied for processing and the like, but urethane liquefied using an organic solvent such as toluene is called a solvent-based urethane polymer, and most of the urethane polymers are organic solvent-based. On the other hand, the water-based urethane polymer is a urethane liquefied by using water instead of the organic solvent, and since the water-based urethane polymer can be liquefied without using the organic solvent, it is an environment-friendly material. Can be said.

  Examples of the water-based urethane polymer preferably used in the present invention include carbonate-based polymers, polycarbonate-based polymers, ester-based polymers, ether-based polymers, ester / acrylic-based polymers and the like.

For example, as the water-based urethane polymer of the carbonate-based, trade name of Dai-ichi Kogyo Seiyaku Co., Ltd. "F-8082D" (100% modulus 24N / ^mm 2), the trade name of "Super Flex 420" (100 modulus 17N / mm ² ), Trade name “F-2954D” (100% modulus 5 N / mm ² ), trade name “F-2954D-5” (100% modulus 12 N / mm ² ), trade name “Superflex 470” (100% modulus 2 0.5 N / mm ² ), trade name “Superflex 460” (100% modulus 0.9 N / mm ² ), trade name “F-2968D” (100% modulus 1.5 N / mm ² ), etc. are commercially available. As an example of the ester-based water-based urethane polymer, a product made by ADEKA Co., Ltd. Trade name "HUX 232" (100% modulus 25N / ^mm 2), the trade name of "HUX-380" (100 modulus 8.4N / ^mm 2), the trade name of "HUX-210" (100% modulus 2.1N / mm ² ) and the like are commercially available, and examples of the polycarbonate-based water-based urethane polymer include trade names “HUX-561” (100% modulus 5 N / mm ² ) manufactured by ADEKA Corporation and trade names “HUX. -564 "and the like are commercially available, and as the ether-based water-based urethane polymer, trade name" HUX-350 "(100% modulus 25 N / mm ² ) manufactured by ADEKA Co., Ltd., trade name" HUX-550 "(100% modulus ^{27N / mm 2 (10%)} ) such as those commercially available It mentioned and, as the water-based urethane polymer of an ester / acrylic, K.K. ADEKA "HUX 401" (100% modulus 19N / mm ^2), and the like as those commercially available. In the present invention, those having a coefficient of static friction of the surface protective layer within the range of the present invention can be appropriately selected and used from these commercially available products. Further, two or more kinds of water-based polyurethane may be used together.

  The surface protective layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention preferably contains a crosslinking agent. The content of the cross-linking agent is preferably 5 parts by weight or more and 12 parts by weight or less, more preferably 5 parts by weight or more and 11 parts by weight or less with respect to 100 parts by weight of the base resin constituting the surface protective layer. And particularly preferably 5 parts by weight or more and 9 parts by weight or less. When the cross-linking agent is contained in an amount of 5 parts by weight or more and 12 parts by weight or less, it is possible to easily realize an appropriate gel fraction.

Examples of the cross-linking agent preferably used in the surface protective layer include oxazoline-based cross-linking agents, carbodiimide-based cross-linking agents and epoxy-based cross-linking agents.
For example, as the oxazoline-based cross-linking agent, the trade name “(registered trademark) Epocros WS-700” (oxazoline group-containing water-soluble polymer, manufactured by Nippon Shokubai Co., Ltd.), the trade name “(registered trademark) Epocros WS-500” (oxazoline A group-containing water-soluble polymer, manufactured by Nippon Shokubai Co., Ltd., and the like are listed as commercially available, and as the carbodiimide-based cross-linking agent, a trade name “(registered trademark) Carbodilite E-02” (carbodiimide group-containing water-soluble) is used. Polymer, manufactured by Nisshinbo Co., Ltd., trade name “(registered trademark) Carbodilite E-01” (carbodiimide group-containing water-soluble polymer, manufactured by Nisshinbo Co., Ltd.), and the like are listed as commercially available products. As the epoxy-based cross-linking agent, a trade name “(registered trademark) GL-PEP” (epoxy group-containing water-soluble polymer, Made day-shi synthesis Co., Ltd.), trade name "(registered trademark) Denacol EX-313" (epoxy group-containing water-soluble polymer, manufactured by Nagase Chemtex Co., Ltd.) and the like as those commercially available.

  The surface protective layer may further contain additives such as an anti-repellent agent, a thickener, a light stabilizer and an ultraviolet absorber. Anti-repellent agents (leveling agents) include, for example, polyether-modified siloxane, sodium perfluoroalkenyloxybenzenesulfonate, polyester-modified siloxane, aralkyl-modified siloxane, and the like, and light stabilizers include, for example, water dispersion. Type hindered amine light stabilizers and the like, and examples of the ultraviolet absorbers include water-dispersed benzotriazole type ultraviolet absorbers.

  The surface protection layer has a coefficient of static friction of 0.05 to 1.50 on the surface, more preferably 0.05 to 1.00, and particularly preferably 0.05 to 0.5. If the coefficient of static friction of the surface protective layer is 0.05 or more and 1.50 or less, good surface slipperiness can be realized.

  From the viewpoint of the effect of flexibility (curved surface followability), it is preferable that the maximum stress value of the surface protective layer from 0% to a 100% stretched state is 5.0 MPa or more and 24.0 MPa or less, and further preferable. Is 10.0 MPa or more and 20.0 MPa or less, and particularly preferably 12.5 MPa or more and 17.5 MPa or less.

  Here, the maximum stress value means that the surface protection layer is subjected to a tensile test at a tensile speed of 200 mm / min, a chuck distance of 30 mm, a temperature of 20 ° C. and a thickness of 500 μm to obtain a stress-strain curve, and 0% to 100% of the surface protection layer. % The maximum value of the stress per unit area up to the stretched state (maximum stress value).

  The base material layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention is particularly limited as long as the maximum stress value exceeds 0% of the multilayer pressure-sensitive adhesive sheet and reaches a 10% stretched state of 0.5 to 4.0 MPa. Although it can be used without being treated, for example, it is preferable that it contains at least a urethane polymer, and it is preferable that it is a film made of a urethane polymer or a composite film containing a (meth) acrylic polymer and a urethane polymer. Here, examples of the urethane-based polymer include a homopolymer of urethane, a copolymer of urethane and a polymer other than urethane, and the like.

  The base material layer preferably has a maximum stress value of 0.5 MPa or more and less than 3.5 MPa in excess of 0% of the base material layer and up to a 10% elongation state, more preferably 1.0 MPa or more, It is 3.0 MPa or less, particularly preferably 1.5 MPa or more and 2.0 MPa or less.

  Here, the maximum stress value means that the base material layer (width 10 mm, length 160 mm) is subjected to a tensile test at a tensile speed of 200 mm / min, a chuck distance of 100 mm and a temperature of 23 ° C. to obtain a stress-strain curve. The maximum value of the stress per unit area (maximum stress value) up to 0% to 10% elongation state.

  In the present invention, as the urethane-based polymer used for the base material layer, a urethane homopolymer or copolymer satisfying the above stress value is preferably used, and the urethane homopolymer is obtained by reacting a polyol and a polyisocyanate, for example. Obtainable. Examples of the urethane-based polymer preferably used in the present invention include adipate / ester-based thermoplastic polyurethane, polyether-based thermoplastic polyurethane, polycarbonate-based thermoplastic polyurethane, and polycaprolactone-based thermoplastic polyurethane. For example, as an adipate ester thermoplastic polyurethane, a product manufactured by Nippon Matai Co., Ltd. can be commercially obtained.

  Further, the base material layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention is preferably a composite film containing a (meth) acrylic polymer and a urethane polymer.

  The weight ratio of the (meth) acrylic polymer and the urethane polymer in this composite film is preferably (meth) acrylic polymer / urethane polymer = 1/99 to 80/20. If the content ratio of the (meth) acrylic polymer is less than 1/99, the viscosity of the precursor mixture may be high and the workability may be deteriorated. If it exceeds 80/20, flexibility and strength as a film may be obtained. It may not be possible.

  In the present invention, the (meth) acrylic polymer preferably comprises at least a (meth) acrylic acid-based monomer and an acrylic component containing a monofunctional (meth) acrylic-based monomer, and particularly, the glass transition of the homopolymer. It is preferable to use a monofunctional (meth) acrylic monomer having a temperature (Tg) of 0 ° C. or higher. Furthermore, in the present invention, the (meth) acrylic polymer preferably comprises an acrylic component further containing a monofunctional (meth) acrylic monomer having a homopolymer glass transition temperature (Tg) of less than 0 ° C.

  In the present invention, the (meth) acrylic acid-based monomer is a (meth) acrylic-based monomer having a carboxyl group, and examples thereof include acrylic acid, methacrylic acid, maleic acid and crotonic acid. Of these, acrylic acid is particularly preferable. The content of this (meth) acrylic acid-based monomer is 1% by weight or more and 15% by weight or less, preferably 2% by weight or more and 10% by weight or less, in the composite film precursor described later. When the content of the (meth) acrylic acid-based monomer is less than 1% by weight, the reaction takes a long time and it is very difficult to form a film, and there is a problem that the strength of the film is insufficient. . When the content of the (meth) acrylic acid-based monomer exceeds 15% by weight, the water absorption rate of the film increases, which may cause a problem in water resistance. When a composite film is used as the base material, the (meth) acrylic acid-based monomer has a great influence on the compatibility with the urethane component and the acrylic component, and is an essential component having an extremely important function.

In the present invention, the term “film” includes a sheet, and the term “sheet” includes a film. Further, in the present invention, when the expression “(meth) acrylic” is used as in the case of (meth) acrylic polymer and (meth) acrylic acid type monomer, methacrylic and acrylic are collectively referred to as concepts. Further, even if the word "acrylic" is used, the concept includes methacrylic as long as there is no problem in common sense.
In the present invention, "containing as a main component" means that the content is 50% by weight or more, preferably 90% by weight or more, and 100% is also included.

  In the present invention, examples of the monofunctional (meth) acrylic monomer having Tg of 0 ° C. or higher include acryloylmorpholine, isobornyl acrylate, dicyclopentanyl acrylate, t-butyl acrylate, cyclohexyl acrylate, and lauryl acrylate. To be These may be used alone or in combination of two or more.

  In the present invention, it is preferable to use at least one selected from the group consisting of acryloylmorpholine, isobornyl acrylate, and dicyclopentanyl acrylate as the monofunctional (meth) acrylic monomer having Tg of 0 ° C. or higher, It is more preferable to use acryloylmorpholine and / or isobornyl acrylate, or acryloylmorpholine and / or dicyclopentanyl acrylate, and it is particularly preferable to use isobornyl acrylate.

  The content of the monofunctional (meth) acrylic monomer having a Tg of 0 ° C or higher is preferably 20% by weight or more and 99% by weight or less, and 30% by weight or more and 98% by weight or less in the acrylic component. Is more preferable. If the content of the monofunctional (meth) acrylic monomer is less than 20% by weight, the film may have insufficient strength, and if it exceeds 99% by weight, the film becomes too rigid and brittle. There are cases.

In the present invention, examples of the monofunctional (meth) acrylic monomer having Tg of less than 0 ° C. include n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isobutyl acrylate, 2-methoxyethyl acrylate, and tetrahydro. Examples thereof include fluorofuryl acrylate, phenoxyethyl acrylate, ethoxyethyl acrylate and 3-methoxybutyl acrylate. These may be used alone or in combination of two or more.
In the present invention, it is particularly preferable to use n-butyl acrylate as the monofunctional (meth) acrylic monomer having Tg of less than 0 ° C.

  A monofunctional (meth) acrylic monomer having a Tg of less than 0 ° C. may not be contained (content is 0% by weight), but when it is contained, the content is more than 0% by weight in the acrylic component. It is more preferably 50% by weight or less, and more preferably more than 0% by weight and 45% by weight or less. When the content of the monofunctional (meth) acrylic monomer exceeds 50% by weight, the film strength may be insufficient.

  The type, combination, usage amount, etc. of the (meth) acrylic monomer are appropriately determined in consideration of compatibility with urethane, polymerizability at the time of photocuring by radiation or the like, and characteristics of the high molecular weight product obtained.

  In the present invention, together with the (meth) acrylic monomer, vinyl acetate, vinyl propionate, styrene, acrylamide, methacrylamide, mono- or diester of maleic acid, and derivatives thereof, N-methylol acrylamide, glycidyl acrylate, glycidyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl methacrylamide, 2-hydroxypropyl acrylate, N, N-dimethylacrylamide, N, N-diethylacrylamide, imide acrylate, N-vinylpyrrolidone, oligoester acrylate , Ε-caprolactone acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, methoxylated cyclododecatriene Acrylate may be copolymerized monomer such as methoxyethyl acrylate. The type and amount of these copolymerized monomers are appropriately determined in consideration of the properties of the composite film.

  Further, other polyfunctional monomers may be added within the range that does not impair the characteristics. Examples of polyfunctional monomers include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol. Examples thereof include tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, urethane acrylate, epoxy acrylate, polyester acrylate and the like, and trimethylolpropane tri (meth) acrylate is particularly preferable.

  The polyfunctional monomer may be included in an amount of 1 part by weight or more and 20 parts by weight or less based on 100 parts by weight of the acrylic monomer. When the content of the polyfunctional monomer is 1 part by weight or more, the cohesive force of the composite film is sufficient, and when it is 20 parts by weight or less, the elastic modulus does not become too high and unevenness on the surface of the adherend occurs. You can follow.

  The urethane polymer is obtained by reacting a diol with a diisocyanate. A catalyst is generally used for the reaction between the hydroxyl group of the diol and the isocyanate, but according to the present invention, the reaction is promoted without using a catalyst having an environmental load such as dibutyltin dilaurate or tin octoate. Can be made.

  Examples of the low molecular weight diol include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol and hexamethylene glycol.

  As the high molecular weight diol, a polyether polyol obtained by addition polymerization of ethylene oxide, propylene oxide, tetrahydrofuran or the like, or the above divalent alcohol, 1,4-butanediol, 1,6-hexanediol, etc. Examples thereof include polyester polyols made of a polycondensation product of the above alcohol and a divalent basic acid such as adipic acid, azelaic acid and sebacic acid, acrylic polyols, carbonate polyols, epoxy polyols and caprolactone polyols. Among these, for example, polyoxytetramethylene glycol (PTMG) and polyalkylene carbonate diol (PCD) are preferably used.

  Examples of the acrylic polyol include a copolymer of a monomer having a hydroxyl group, a copolymer of a hydroxyl group-containing substance and an acrylic monomer, and the like. Examples of the epoxy polyol include amine-modified epoxy resin.

  In the present invention, the urethane polymer does not contain a crosslinked structure. The diol used to form the urethane polymer is preferably a linear diol. However, the diol may be a side chain diol or a diol having a branched structure as long as the condition that the urethane polymer is not formed with a crosslinked structure is satisfied. That is, the urethane polymer that constitutes the composite film of the present invention does not contain a crosslinked structure, and therefore is structurally completely different from the IPN structure.

  In the present invention, the above-mentioned diols can be used alone or in combination in consideration of solubility in acrylic monomers, reactivity with isocyanates, and the like. When strength is required, it is effective to increase the amount of urethane hard segment by the low molecular weight diol. When importance is attached to elongation, it is preferable to use a diol having a large molecular weight alone. Polyether polyols are generally inexpensive and have good water resistance, and polyester polyols have high strength. In the present invention, the type and amount of the polyol can be freely selected according to the use and purpose, and the characteristics of the substrate to be applied, the reactivity with isocyanate, the compatibility with acrylic, etc. Also, the type, molecular weight and amount of the polyol can be appropriately selected.

  Examples of the diisocyanate include aromatic, aliphatic, and alicyclic diisocyanates, and dimers and trimers of these diisocyanates. Examples of aromatic, aliphatic and alicyclic diisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), naphthylene diisocyanate (NDI), phenylene diisocyanate (PPDI), m. -Tetramethylxylylene diisocyanate (TMXDI), methylcyclohexanediisocyanate (hydrogenated TDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexanediisocyanate (hydrogenated PPDI), bis (isocyanatomethyl) cyclohexane (hydrogenated XDI), norbornene Diisocyanate (NBDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), butanedi Cyanate, 2,4-hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and the like. Moreover, these dimers, trimers, and polyphenylmethane diisocyanate are used. Examples of the trimer include isocyanurate type, buret type, and allophanate type, which can be appropriately used.

  Among these, especially, methylcyclohexane diisocyanate (hydrogenated TDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexane diisocyanate (hydrogenated PPDI), bis (isocyanatomethyl) cyclohexane (hydrogenated XDI), norbornene diisocyanate (NBDI). ), Isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), butane diisocyanate, 2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and other aliphatic or alicyclic diisocyanates are preferred. used. This is because the use of an aromatic diisocyanate containing a benzene ring is not preferable because a colored substance having a conjugated structure is likely to be produced by a photoreaction, and in the present invention, a benzene ring-free, yellowing-resistant and yellow-free type is used. Modified aliphatic and alicyclic diisocyanates are preferably used.

  These diisocyanates can be used alone or in combination. The type and combination of diisocyanates may be appropriately selected from the viewpoints of the characteristics of the support to which the composite film is applied (coated, etc.), the solubility in acrylic monomers, the reactivity with hydroxyl groups, and the like.

  In the present invention, the urethane polymer is hexamethylene diisocyanate (HDI), hydrogenated tolylene diisocyanate (HTDI), hydrogenated 4,4-diphenylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and hydrogenated xylene diisocyanate. It is preferably formed using at least one diisocyanate selected from the group consisting of (HXDI), and hydrogenated xylene diisocyanate is particularly preferable.

  In the present invention, the amount of the diol component and diisocyanate component used to form the urethane polymer is preferably NCO / OH (equivalent ratio) of 1.1 or more and 2.0 or less, and 1.12 or more, 1 or more. It is more preferably 0.60 or less, and particularly preferably 1.15 or more and 1.40 or less. If the NCO / OH (equivalent ratio) is less than 1.1, the molecular weight of the urethane polymer becomes too large, and the viscosity of the composite film precursor (syrup solution) becomes large, which makes it difficult to work in the subsequent sheet forming process. There is. Further, when the NCO / OH (equivalent ratio) exceeds 2.0, the molecular weight of the urethane polymer becomes small, and the breaking strength tends to decrease.

  In the present invention, the weight ratio of the acrylic component and the urethane component forming the composite film is such that the acrylic component / urethane component is 0.25 or more and 4.00 or less, preferably 0.4 or more and 2 or more. It is less than or equal to 0.4, particularly preferably greater than or equal to 0.5 and less than or equal to 1.9. If the acrylic component / urethane component is less than 0.25, the viscosity of the syrup solution becomes large, which may make the work difficult in the subsequent sheet forming process. Further, when the acrylic component / urethane component exceeds 4.00, the amount of urethane polymer in the composite film becomes less than 25%, the tensile breaking strength decreases, and it may not be practical.

  A hydroxyl group-containing acrylic monomer may be added to the urethane polymer. By adding a hydroxyl group-containing acrylic monomer, a (meth) acryloyl group can be introduced at the molecular end of the urethane prepolymer, and copolymerizability with the (meth) acrylic monomer is imparted to the urethane component and the acrylic component. It is possible to improve the compatibility of the above and improve the S-S characteristics such as breaking strength. Examples of the hydroxyl group-containing acrylic monomer used here include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and hydroxyhexyl (meth) acrylate. The amount of the hydroxyl group-containing acrylic monomer used is preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the urethane polymer.

  In the composite film, if necessary, a commonly used additive such as an ultraviolet absorber, an antioxidant, an antioxidant, a filler, a pigment, a colorant, a flame retardant, an antistatic agent, a light stabilizer, etc. It can be added within a range that does not impair the effects of the present invention. These additives are used in usual amounts depending on the kind. These additives may be added in advance before the polymerization reaction of diisocyanate and diol, or may be added before the urethane polymer and the acrylic monomer are polymerized.

Examples of the ultraviolet absorber (UVA) used in the present invention include 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (for example, Ciba Japan Co., Ltd.) as a benzotriazole type ultraviolet absorber. Manufactured by TINUVIN PS), benzenepropanoic acid and 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C ₇ -C ₉ side chain and straight chain). Ester compound with chain alkyl) (for example, "TINUVIN 384-2" manufactured by Ciba Japan), octyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazole). 2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- A mixture with 5-chloro-2H-benzotriazol-2-yl) phenyl] propionate (for example, "TINUVIN 109" manufactured by Ciba Japan), 2- (2H-benzotriazol-2-yl) -4,6. -Bis (1-methyl-1-phenylethyl) phenol (for example, "TINUVIN 900" manufactured by Ciba Japan), 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1- Phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (for example, "TINUVIN 928" manufactured by Ciba Japan), methyl-3- (3- (2H-benzotriazole-2-) Yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 reaction product (e.g. Ba Japan's TINUVIN 1130 "), 2- (2H-benzotriazol-2-yl) -p-cresol (for example, Ciba Japan's" TINUVIN P "), 2- [5-chloro (2H. ) -Benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol (for example, TINUVIN 326 "manufactured by Ciba Japan), 2- (2H-benzotriazol-2-yl) -4. , 6-di-tert-pentylphenol (for example, TINUVIN 328 "manufactured by Ciba Japan), 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) ) Phenol (for example, TINUVIN 329 "manufactured by Ciba Japan), 2-2'-methylenebis [6- (2H-benzotriazole 2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] (for example, TINUVIN 360 ″ manufactured by Ciba Japan), methyl-3- (3- (2H-benzotriazole-2). -Yl) -5-tert-butyl-4-hydroxyphenyl) propionate and a reaction product of polyethylene glycol 300 (for example, "TINUVIN 213" manufactured by Ciba Japan), 2- (2H-benzotriazole-2- Yl) -6-dodecyl-4-methylphenol (for example, "TINUVIN 571" manufactured by Ciba Japan), 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimido-methyl)- 5-methylphenyl] benzotriazole (for example, "Sumisorb 250" manufactured by Sumitomo Chemical Co., Ltd.), 2,2'-methylenebis [ - (benzotriazol-2-yl) -4-tert-octylphenol] (e.g., ADEKA made of "ADKSTAB LA31"), and the like.

  Examples of the hydroxyphenyl triazine-based ultraviolet absorber include 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hydroxyphenyl and [[ (C10-C16, mainly C12-C13 alkyloxy) methyl] oxirane reaction product (for example, "TINUVIN 400" manufactured by Ciba Japan), 2- (2,4-dihydroxyphenyl) -4,6 -Bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester as a reaction product (for example, "TINUVIN 405" manufactured by Ciba Japan), 2 , 4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine (for example, "TINUVIN 460" manufactured by Ciba Japan), 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol (for example, Ciba Japan) "TINUVIN 1577"), 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine (for example, , "TINUVIN 479" manufactured by Ciba Japan Co., Ltd.) and the like.

  Examples of the benzophenone-based ultraviolet absorber include "CHIMASSORB 81" manufactured by Ciba Japan. Examples of the benzoate-based ultraviolet absorber include 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (for example, "TINUVIN 120" manufactured by Ciba Japan Co., Ltd.). ) And the like.

  In the present invention, the above ultraviolet absorbers may be used alone or in combination of two or more.

  The total amount of the ultraviolet absorber used is preferably 0.1% by weight or more and 4.0% by weight or less, and 0.5% by weight or more and 2.0% by weight, based on 100% by weight of the film precursor. The following is more preferable. When the content of the ultraviolet absorber is 0.1% by weight or more, the absorption of ultraviolet light which causes deterioration and coloring is sufficient, and when it is 4.0% by weight or less, the coloring by the ultraviolet absorber itself is caused. There is no.

  The light stabilizer used in the present invention is preferably a hindered amine light stabilizer (HALS). As the hindered amine light stabilizer used in the present invention, for example, a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (for example, manufactured by Ciba Japan Co., Ltd. "TINUVIN 622"), a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and N, N ', N ", N"'-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino) -triazin-2-yl) -4,7-diazadecane-1,10 A one-to-one reaction product with a diamine (for example, "TINUVIN 119" manufactured by Ciba Japan Co., Ltd.), dibutylamine 1,3-triazine N, N'-bis (2,2,6, Polycondensate of 6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine (for example, manufactured by Ciba Japan Co., Ltd. "TINUVIN 2020"), poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {2,2,6,6-tetra Methyl-4-piperidyl} imino] hexamethylene {(2,6,6-tetramethyl-4-piperidyl) imino}) (for example, “TINUVIN 944” manufactured by Ciba Japan), bis (1,2,2) , 6,6-Pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (for example, "TINUVIN" manufactured by Ciba Japan). 65 "), bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (for example," TINUVIN 770 "manufactured by Ciba Japan), and bis (2,2,6,6- Reaction product of tetramethyl-1- (octyloxy) -4-piperidinyl) ester (1,1-dimethylethylhydroperoxide) and octane (for example, “TINUVIN 123” manufactured by Ciba Japan), bis (1 , 2,2,6,6-Pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate (for example, manufactured by Ciba Japan Co., Ltd. "TINUVIN 144"), cyclohexane and N-butyl peroxide-2,2,6,6-tetramethyl-4-piperidineamine-2,4,6-trichloro-1, , 5-triazine and 2-aminoethanol (for example, "TINUVIN 152" manufactured by Ciba Japan), bis (1,2,2,6,6-pentamethyl-4-) Examples include a mixture of piperidyl) sebacate and methyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate (for example, "TINUVIN 292" manufactured by Ciba Japan).

  In the present invention, a small amount of solvent may be added to adjust the viscosity of the coating. The solvent can be appropriately selected from commonly used solvents, and examples thereof include ethyl acetate, toluene, chloroform and dimethylformamide.

  In the present invention, the composite film contains, for example, an acrylic monomer as a diluent to react with a diol and a diisocyanate in the acrylic monomer to form a urethane polymer, and contains the acrylic monomer and the urethane polymer as main components. The mixture is applied on a support (which has been peeled off if necessary), etc., and depending on the type of photopolymerization initiator, ionization of α rays, β rays, γ rays, neutron rays, electron rays, etc. A composite film can be formed by irradiating with radiation such as sexual radiation and ultraviolet rays, visible light and the like to cure, and then peeling and removing the support and the like. Alternatively, the composite film may be obtained by laminating the composite film on the support or the like without peeling and removing the support or the like.

  Specifically, the diol is dissolved in an acrylic monomer, and then diisocyanate or the like is added to react with the diol to adjust the viscosity, and the viscosity is adjusted to a support or the like, or if necessary, the support or the like is peeled off. A composite film can be obtained by coating the treated surface and then curing it using a low pressure mercury lamp or the like. In this method, the acrylic monomer may be added at once during the urethane synthesis, or may be added in several divided portions. Further, the diisocyanate may be dissolved in the acrylic monomer and then reacted with the diol. According to this method, the molecular weight is not limited, and a high molecular weight polyurethane can be produced. Therefore, the molecular weight of the urethane finally obtained can be designed to be an arbitrary size.

  At this time, in order to avoid polymerization inhibition due to oxygen, a release-treated sheet (separator or the like) may be placed on the mixture applied on the substrate sheet or the like to block oxygen, or an inert gas may be filled. The oxygen concentration may be lowered by putting a base material in the container.

  In the present invention, the type of radiation or the type of lamp used for irradiation can be appropriately selected, and low-pressure lamps such as fluorescent chemical lamps, black lights, and sterilization lamps, high-pressure lamps such as metal halide lamps and high-pressure mercury lamps can be selected. A lamp or the like can be used.

The irradiation amount of ultraviolet rays or the like can be arbitrarily set according to the required characteristics of the film. Generally, the dose of ultraviolet rays, 100~5,000mJ / cm ^2, preferably not 1,000~4,000mJ / cm ^2, more preferably a 2,000~3,000mJ / cm ^2. If the irradiation amount of ultraviolet rays is less than 100 mJ / cm ² , a sufficient polymerization rate may not be obtained, and if it is more than 5,000 mJ / cm ² , deterioration may occur.

  Further, the temperature when irradiating with ultraviolet rays or the like is not particularly limited and can be arbitrarily set, but if the temperature is too high, the termination reaction due to the heat of polymerization is likely to occur, which is likely to cause deterioration of characteristics. Ordinarily, the temperature is 70 ° C or lower, preferably 50 ° C or lower, and more preferably 30 ° C or lower.

  The photopolymerization initiator is contained in the mixture containing the urethane polymer and the acrylic monomer as main components. The photopolymerization initiator may be used without particular limitation, and examples thereof include ketal photopolymerization initiators, α-hydroxyketone photopolymerization initiators, α-aminoketone photopolymerization initiators, and acylphosphine oxide photopolymerization initiators. Polymerization initiator, bezophenone photopolymerization initiator, thioxanthone photopolymerization initiator, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photoactive oxime photopolymerization initiator Agents, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators and the like can be used.

  Examples of the ketal-based photopolymerization initiator include, for example, 2,2-dimethoxy-1,2-diphenylethan-1-one (commercially available, "Irgacure 651" manufactured by Ciba Specialty Chemicals). Etc.) and the like.

  Examples of the α-hydroxyketone-based photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone (commercially available, "IRGACURE 184" manufactured by Ciba Japan Co., Ltd.), 2-hydroxy-2- Methyl-1-phenylpropan-1-one (as commercially available, "Darocur 1173" manufactured by Ciba Japan Co., Ltd.), 1- [4- (2-hydroxyethoxy) -phenyl] -2 -Hydroxy-2-methyl-1-propan-1-one (commercially available, "IRGACURE 2959" manufactured by Ciba Japan Co., Ltd.) and the like can be mentioned.

  Examples of the α-aminoketone-based photopolymerization initiator include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (commercially available, Ciba "Irgacure 907" manufactured by Japan Co., Ltd.), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (commercially available, manufactured by Ciba Japan Co., Ltd. “Irgacure 369” etc.) and the like.

  Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (commercially available, "Lucirin TPO" manufactured by BASF) and the like.

  Examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole. Examples include methyl ether.

  Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl). Examples include dichloroacetophenone.

  Examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalene sulfonyl chloride and the like, and examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (O-ethoxycarbonyl) -oxime and the like can be mentioned.

  Examples of the benzoin-based photopolymerization initiator include benzoin and the like, and examples of the benzyl-based photopolymerization initiator include benzyl and the like.

  Examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenylketone.

  Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone and dodecylthioxanthone.

  The thickness of the surface protective layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention is preferably 2 to 50 μm, more preferably 5 to 40 μm, and further preferably 8 to 30 μm. If the thickness of the surface protective layer is less than 2 μm, defects such as pinholes where the surface protective layer is not formed are likely to occur, and the characteristics of the surface protective layer may not be fully exhibited. When it exceeds 50 μm, the physical properties of the surface protective layer may deteriorate the physical properties of the base material layer.

  The thickness of the base material layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention can be appropriately selected depending on the purpose and the like, for example, the type and location of the object to be covered and protected, and is not particularly limited, but is 100 μm or more. Is preferable, and 140 μm or more is more preferable. The upper limit of the thickness is preferably about 1 mm. The thickness of the base material layer is preferably about 50 to 800 μm, and more preferably about 100 to 600 μm in the case of chipping used for protecting the body of an automobile. Further, in the case of aircraft use, the thickness is about 50 to 1,000 μm, more preferably about 200 to 800 μm. In the case of motorcycle application, the thickness is preferably about 50 to 800 μm, more preferably about 100 to 600 μm.

  In the present invention, the surface protective layer can be formed using, for example, a coating liquid for the surface protective layer, which is composed of a water-based urethane polymer or a solvent-based urethane polymer. For example, a laminate (multilayer sheet) can be obtained by applying a surface protective layer coating liquid on the base material layer, and drying and curing the coating liquid to form a surface protective layer.

  Alternatively, for example, the surface protective layer coating liquid is applied onto the PET film subjected to the release treatment and dried to form the surface protective layer. A laminate (multi-layer sheet) can be obtained by applying a composite film coating liquid containing an acrylic monomer and a urethane polymer onto the surface protective layer and irradiating it with ultraviolet rays to cure it.

  In the present invention, the multilayer sheet may have another film laminated on the base material layer within a range that does not impair the effects of the present invention. Examples of materials for forming other films include polyester resins such as polyethylene terephthalate (PET), polyolefin resins such as polyethylene (PE) and polypropylene (PP), polyimide (PI), polyether ether ketone (PEEK). In addition to thermoplastic resins such as polyvinyl chloride (PVC), polyvinylidene chloride resin, polyamide resin, polyurethane resin, polystyrene resin, acrylic resin, fluorine resin, cellulose resin, polycarbonate resin, etc. , Thermosetting resins and the like.

  The multilayer pressure-sensitive adhesive sheet of the present invention preferably has a surface protective layer as an outermost surface layer on one surface of the base material layer and a pressure-sensitive adhesive layer on the other surface.

  The pressure-sensitive adhesive forming this pressure-sensitive adhesive layer is not particularly limited, and general ones such as acrylic type, rubber type, and silicon type can be used, but adhesiveness at low temperature and retention at high temperature, An acrylic adhesive is preferable in consideration of cost and the like.

  As the acrylic pressure-sensitive adhesive, an acrylic copolymer (two or more kinds may be used) in which a monomer component having an acrylic ester as a main component is copolymerized with a monomer component having a functional group such as a carboxyl group or a hydroxyl group. An acrylic pressure-sensitive adhesive containing can be used.

  Examples of the acrylate ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-. Butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate. Acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, un Syl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl ( Examples thereof include (meth) acrylate, eicosyl (meth) acrylate, isobornyl (meth) acrylate, and 1-adamantyl (meth) acrylate. These alkyl (meth) acrylates may be used either individually or in combination of two or more.

  The following monomer components can be copolymerized with the above alkyl (meth) acrylate. Examples of the copolymerizable monomer component include monomers containing a carboxyl group such as (meth) acrylic acid, itaconic acid, maleic acid, crotonic acid, fumaric acid, carboxyethyl (meth) acrylate, and carboxypentyl (meth) acrylate. 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxy (meth) acrylate Hydroxyl group-containing monomers such as octyl, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) -methyl acrylate; glycidyl (meth) acrylate, methylglycidyl (meth) Acry Glycidyl group-containing monomers such as acrylate; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethyl ( (Meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, (meth) acryloylmorpholine, N-vinyl-2-piperidone, N-vinyl-3 -Morpholinone, N-vinyl-2-caprolactam, N-vinyl-2-pyrrolidone, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-cyclohexylmaleimide, N -Phenylmaleimide, N-a Leroy pyrrolidine, t- butyl aminoethyl (meth) nitrogen-containing monomers such as acrylates, styrene derivatives and styrene, monomers such as vinyl acetate and the like. If necessary, one or more of these monomers can be used by copolymerizing them with a (meth) acrylic acid ester.

  The pressure-sensitive adhesive used in the present invention comprises at least one kind selected from the group consisting of 2-ethylhexyl acrylate and isononyl acrylate, and at least one kind of carboxyl group-containing monomer selected from the group consisting of acrylic acid and methacrylic acid. It is preferable to include. That is, as the pressure-sensitive adhesive used in the present invention, a copolymer obtained by copolymerizing 2-ethylhexyl acrylate, isononyl acrylate or the like as a main monomer and a carboxyl group-containing monomer such as acrylic acid or methacrylic acid can be used. .

  The thickness of the pressure-sensitive adhesive layer is not particularly limited and can be set arbitrarily, but is usually preferably 20 μm or more, more preferably 30 μm or more, and particularly preferably 40 μm or more. However, it is preferable that the upper limit value is usually about 100 μm.

  In the present invention, the pressure-sensitive adhesive layer is formed, for example, by directly applying a solvent-based or emulsion-based pressure-sensitive adhesive to the base material layer and drying it, or by applying these pressure-sensitive adhesives to release paper to form the pressure-sensitive adhesive layer in advance. However, a method of laminating this pressure-sensitive adhesive layer to the base material layer or the like can be applied. A method of applying a radiation-curable pressure-sensitive adhesive to the base material layer and irradiating both the pressure-sensitive adhesive layer and the film with radiation to simultaneously cure the base material layer and the pressure-sensitive adhesive layer may also be applied. it can.

In the present invention, the coefficient of static friction of the multilayer adhesive sheet is determined by measuring the coefficient of static friction of the outermost surface layer according to JIS K7125. That is, a multilayer adhesive sheet of a predetermined size is fixed on a standard test plate, a sliding piece is placed on the multilayer adhesive sheet, and the sliding piece is pulled while applying normal force (uniform pressure distribution) and the maximum load is measured. Then, the static friction coefficient is calculated using the following calculation formula.
μ = Fs / Fp
(Μ: static friction coefficient, Fs: static friction force (N), Fp: normal force)

  The multilayer pressure-sensitive adhesive sheet of the present invention needs to have a maximum stress value of 0.5 to 4.0 MPa in a state where the multilayer pressure-sensitive adhesive sheet exceeds 0% and extends to 10%, and preferably 1.0 MPa or more and 3 MPa. 0.0 MPa or less, and particularly preferably 1.5 MPa or more and 2.0 MPa or less. If the maximum stress value of the multilayer pressure-sensitive adhesive sheet exceeds 0% and is 10% stretched to 0.5 to 4.0 MPa, good curved surface followability can be achieved. If this maximum stress value is too low (for example, less than 0.5 MPa), the handling property (easiness of handling of the tape) at the time of sticking to an adherend having a large area will deteriorate.

  Here, the maximum stress value means that a multilayer pressure-sensitive adhesive sheet (width 10 mm, length 160 mm) is subjected to a tensile test at a pulling speed of 200 mm / min, a chuck distance of 100 mm and a temperature of 23 ° C. to obtain a stress-strain curve. It means the maximum value of stress per unit area (maximum stress value) up to 1% to 10% elongation.

  The multilayer pressure-sensitive adhesive sheet of the present invention is required to be transparent in order to directly reflect the color etc. of the coated surface of the adherend on the appearance, but it is required to use a pigment or the like in the same color as the coated surface. It may be colored or may be colored with a different color to be used as a paint substitute adhesive sheet.

  The multilayer pressure-sensitive adhesive sheet of the present invention can use an application sheet for improving the operation of sticking the pressure-sensitive adhesive sheet, for example, for sticking positioning.

The multi-layer pressure-sensitive adhesive sheet of the present invention has excellent conformability to a curved surface and can be suitably used even for an adherend having a severe three-dimensional curved surface. Further, the multilayer adhesive sheet of the present invention is excellent in solvent resistance, for example, as a film for surface protection and decoration of the adherend exposed to harmful environments such as outdoor weather, solvent, dust, oils and fats and marine environment. Can be used. In addition, it is used for protection of transport machinery such as motorcycles, bicycles, railway vehicles, ships, snowmobiles, gondola, lifts, escalators, automobiles, aircraft, etc., especially for protecting body painting surfaces of automobiles, aircraft, motorcycles, etc. It is also suitable as a multilayer adhesive sheet, body protection film, etc.

  The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In addition, in the following Examples, unless otherwise indicated, parts mean parts by weight, and% means% by weight. The measuring methods and evaluation methods used in the following examples are shown below.

(Measurement method and evaluation method)
(1) Measurement of maximum stress value A multilayer pressure-sensitive adhesive sheet was cut into a width of 10 mm and a length of 160 mm, a tensile test was carried out at a tensile speed of 200 mm / min, a chuck distance of 100 mm and a temperature of 23 ° C. to obtain a stress-strain curve. . The maximum value of the stress per unit area (maximum stress value) at the time of 0% to 10% elongation of the multilayer adhesive sheet was determined.

(2) Measurement of static friction coefficient A multilayer pressure-sensitive adhesive sheet was cut into a size of width 80 mm x length 100 mm, and this multilayer pressure-sensitive adhesive sheet was stuck on a standard test plate (JISG3141: manufactured by Nippon Test Panel Co., Ltd.) A slide piece was placed on the pressure-sensitive adhesive sheet, and the static friction coefficient of the outermost surface layer (ex. Surface protection layer) was measured according to JIS K7125. The contact area of the sliding piece was 63 mm × 63 mm, the total mass of the sliding piece was 200 g (1.96 N), and a squeegee cloth was attached to the contact surface of the sliding piece with the surface of the adhesive sheet, and the sliding speed was 100 mm / min. The sliding piece was pulled under the conditions to perform the measurement. The static friction coefficient was obtained using the following calculation formula according to JIS K7125.

μ = Fs / Fp
(Μ: static friction coefficient, Fs: static friction force (N), Fp: normal force generated by mass of sliding piece (= 9.8 N / kg × 0.2 kg))

  1A and 1B are schematic diagrams for explaining a method of measuring a static friction coefficient. As shown in FIG. 1 (a), the sample 1 is fixed to the mating material 2 so that the measurement surface of the sample 1 (ex. Multilayer adhesive sheet) faces upward, that is, for example, the adhesive layer of the multilayer adhesive sheet. Is adhered and fixed on the mating material 2 (ex. Standard test plate), a slide piece (contact area 63 mm × 63 mm) is arranged on the measurement surface of the sample 1, and the slide piece is tested at a test speed of 100 mm / min. Pull with. Since the normal force is generated by the sliding piece, the bottom surface of the sliding piece is covered with an elastic material (felt or the like) in order to apply a uniform pressure distribution. The sample 1 may be directly fixed to the mating member 2, or may be fixed by being attached to an auxiliary plate such as a support. Further, the sliding piece may be connected to the load cell via a spring. As shown in FIG. 1 (b), the force increases linearly to give friction and reach the maximum load. This peak represents the static friction force (Fs). The static friction coefficient is obtained from the above calculation formula (μ = Fs / Fp).

(3) Evaluation of solvent resistance The obtained multilayer pressure-sensitive adhesive sheet (width 30 mm, length 50 mm) was attached to a black panel (KINO-1210TW: manufactured by Kansai Paint Co., Ltd.) and multilayered with a cloth impregnated with ethanol. The sheet surface was rubbed 20 times back and forth, and then the multilayer adhesive sheet was evaluated in two stages. The evaluation was performed based on the evaluation criteria shown below.

(Evaluation criteria)
○ White turbidity (dissolution) of the multilayer adhesive sheet is not confirmed.
× White turbidity (dissolution) of the multilayer adhesive sheet is confirmed.

(4) Measurement of gel fraction The obtained surface protective layer (width 100 mm, length 100 mm) was wrapped with # 100 SUS mesh and immersed in DMF for 3 days. Then, the SUS mesh enclosing the surface protective layer was dried at 130 ° C. for 1 hour, and the weight of the SUS mesh was measured. The gel fraction of the surface protective layer was calculated based on the following formula.
(Calculation formula)
Gel fraction (%) = {(weight of surface protective layer after immersion / drying) / (weight of surface protective layer before immersion / drying)} × 100

(5) Evaluation of sticking workability Three-dimensional curved surface portion (size: length 300 mm × width 210 mm, curvature: maximum convex curvature (R = 43.3), maximum concave curvature (R = 34.6) (A part having a curved surface including (see FIG. 2)) was subjected to a sticking work of sticking a multilayer adhesive sheet, and the sticking workability was evaluated. That is, each of the "surface slipperiness" and the "curved surface followability" was evaluated by a score (1 to 4 points), and a total score of both was obtained. However, there are three sticking workers who participated in the test. In addition, the criteria for scoring "surface slipperiness" and "curved surface followability" are: 4 points that are very good, 3 points that are not problematic, 2 points that need a little improvement, and 2 levels that need improvement. Was set as 1 point, and the average value of 3 workers was shown.

From the total score of the sticking workability, the sticking workability was evaluated based on the following evaluation criteria. The total score of the sticking workability as used herein means the score of the curved surface followability + the score of the surface slipperiness.

(Evaluation criteria):
"Excellent" Total workability is 5 or more
"Good" The total score of pasting workability is more than 4.5 points and less than 5 points "Inferior" The total score of pasting workability is 4.5 points or less

  In the case where the evaluation criteria indicates “good”, if the curved surface followability is poor, the work of pressing strongly with the squeegee and the work of rubbing with the squeegee many times increase, and the work efficiency decreases slightly. In addition, if the curved surface followability is poor, the number of pulling operations and repeated operations, that is, the operations of peeling a once-applied part and re-adhering increases, resulting in a slight decrease in work efficiency. Further, if the slipperiness is poor, the squeegee is likely to have streaks or scratches when it is attached, and the work needs to be done carefully, resulting in a decrease in work efficiency.

  When the above evaluation criterion is "poor", if the surface slipperiness is poor, the squeegee does not slide smoothly, and it becomes difficult to remove the remaining air bubbles or water bubbles. In addition, if the surface slipperiness is poor, the squeegee will bite when it is attached, and streaks and scratches are likely to occur, causing problems. Further, if the curved surface following property is poor, bubbles and water bubbles are likely to remain, and a problem is likely to occur. Further, when the curved surface followability is poor, there is a large amount of material surplus (a portion that does not conform to the curved surface).

(Example 1)
<< Preparation of coating liquid for surface protective layer >>
As a coating liquid for the surface protective layer, 55.88 parts of a water-based urethane polymer (carbonate-based polyurethane emulsion manufactured by Dai-ichi Kogyo Kagaku Co., Ltd. (main ingredient, trade name "F-2954D-5"), water-based urethane polymer (first 44.12 parts of carbonate-based polyurethane emulsion (main agent) manufactured by Industrial Chemicals Co., Ltd., trade name "Superflex 460"), and 5 "Epocros WS-700" (manufactured by Nippon Shokubai Co., Ltd.) as an oxazoline crosslinking agent. .81 parts, 0.1 part of a polyether-based modified siloxane (trade name "BYK-349", manufactured by BYK-Chemie Japan Co., Ltd.) as a leveling agent, and sodium perfluoroalkenyloxybenzenesulfonate (trade name "Futgent 100"). (1% diluted solvent), Neos Co., Ltd., 1.00 parts, 1.00 part of trade name "Reolate 216" (manufactured by Elementis Japan K.K.) as a sticking agent, 0.80 part of trade name "UC-606" (manufactured by ADEKA Co., Ltd.) as a water-dispersible light stabilizer, and A trade name "UC-3140" (manufactured by ADEKA Co., Ltd.) as a water-dispersible benzotriazole-based ultraviolet absorber was mixed at a ratio of 0.20 part. Then, the mixture was stirred for 10 minutes at a rotation speed of 2000 rpm using a disper, and then defoamed using a defoaming device (2000 rpm, 10 min) to prepare a surface protective layer coating liquid. The maximum stress value in the 0% to 100% stretched state of the surface protective layer using this coating solution was 6.45 MPa (calculated value), which is shown in Table 1.

<< Formation of surface protection layer >>
As the base material layer, an adipate / ester thermoplastic polyurethane film (manufactured by Nippon Matai Co., Ltd., hardness 86A) having a thickness of 140 μm was used. On the adipate-based thermoplastic polyurethane film (adipate-based TPU film), the prepared coating solution for surface protection layer was applied so that the thickness after curing would be 10 μm, and dried and cured at a temperature of 140 ° C. for 3 minutes. Then, a surface protective layer was formed on one surface of the base material layer.

<< Preparation of adhesive layer >>
A mixture of 94 parts of 2-ethylhexyl acrylate and 6 parts of acrylic acid as a monomer component, and 0.07 part of a trade name “IRGACURE 651” (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, After blending 0.07 part of the name "Irgacure 184" (manufactured by Ciba Specialty Chemicals) until the viscosity reaches about 15 Pa.s (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C). An acrylic composition (UV syrup) partially polymerized by irradiation with ultraviolet rays was produced.

  An adhesive composition was prepared by adding 0.3 part of hexanediol diacrylate to 100 parts of the obtained UV syrup.

  This pressure-sensitive adhesive composition was applied as a release liner to the release-treated surface of a polyethylene terephthalate film (PET film) having a thickness of 50 μm so that the final product had a thickness of 50 μm.

On top of this, a PET film which had been subjected to a release treatment as a separator was overlapped and covered, and then the PET film surface was irradiated with ultraviolet rays (illuminance 290 mW / cm ² , light intensity 4,600 mJ / cm ² ) using a metal halide lamp to cure the PET film. To form an adhesive layer on the release liner. Then, it was dried at 140 ° C. for 3 minutes to dry the unreacted residual acrylic monomer to prepare a pressure-sensitive adhesive layer.

<< Preparation of adhesive sheet >>
The separator was removed, and the surface of the obtained multi-layer sheet opposite to the surface on the side of the surface protective layer (that is, the surface of the base material layer) was laminated using a hand roller so that the pressure-sensitive adhesive layer was overlapped with a thickness of 200 μm. A multilayer adhesive sheet (surface protective layer / base material layer / adhesive layer) was prepared. In addition, in this multilayer pressure-sensitive adhesive sheet, a release liner is provided on the pressure-sensitive adhesive layer.

<< Measurement and evaluation >>
According to the evaluation method described above, the obtained multilayer pressure-sensitive adhesive sheet was evaluated for the maximum stress value in the stretched state of more than 0% to 10%, the solvent resistance was evaluated, and the sticking workability was evaluated. . Furthermore, the coefficient of static friction and the gel fraction of the obtained surface protective layer were measured. The results are shown in Table 2.

(Example 2)
As shown in Table 1, the compounding amount of the coating liquid for the surface protective layer is 45.78 parts of the product name "F-2954D-5", 54.22 parts of the product name "Superflex 460", and the product name "Epocros WS". -700 ", 5.81 parts, trade name" BKY-349 ", 0.1 parts, trade name" Fougent 100 (1% diluted solvent) ", 1.00 parts, trade name" Reolate 216 ", 1. One part of the base material layer was prepared in the same manner as in Example 1 except that the mixing ratio was changed to 00 parts, the trade name "UC-606" was 0.80 parts, and the trade name "UC-3140" was 0.20 parts. A multilayer pressure-sensitive adhesive sheet having a surface protective layer on one side and a pressure-sensitive adhesive layer on the other side was produced. Regarding the obtained multilayer adhesive sheet and surface protective layer, in the same manner as in Example 1, according to the evaluation method shown above, the static friction coefficient was measured, the maximum stress value was measured, the gel fraction was measured, and the solvent resistance was evaluated. The sticking workability was evaluated. The results are shown in Table 2.

(Comparative Example 1)
As shown in Table 1, the blending amount of the coating liquid for the surface protective layer is 55.88 parts under the trade name "F-2954D-5", 44.12 parts under the trade name "Superflex 460", and the trade name "BKY-". 349 "0.1 part, trade name" Fugent 100 (1% diluted solvent) "1.00 part, trade name" Reolate 216 "1.00 part, trade name" UC-606 "0.80 Parts, trade name "UC-3140" was changed to a mixing ratio of 0.20 parts, in the same manner as in Example 1 having a surface protective layer on one surface of the base material layer and sticking to the other surface. A multi-layer pressure-sensitive adhesive sheet having an agent layer was produced. Regarding the obtained multilayer adhesive sheet and surface protective layer, in the same manner as in Example 1, according to the evaluation method shown above, the static friction coefficient was measured, the maximum stress value was measured, the gel fraction was measured, and the solvent resistance was evaluated. The sticking workability was evaluated. The results are shown in Table 2.

(Comparative example 2)
As shown in Table 1, the blending amount of the coating liquid for the surface protective layer is 45.78 parts of the trade name "F-2954D-5", 54.22 parts of the trade name "Superflex 460", and the trade name "BKY-". 349 "0.1 part, trade name" Fugent 100 (1% diluted solvent) "1.00 part, trade name" Reolate 216 "1.00 part, trade name" UC-606 "0.80 Parts, trade name "UC-3140" was changed to a mixing ratio of 0.20 parts, in the same manner as in Example 1 having a surface protective layer on one surface of the base material layer and sticking to the other surface. A multi-layer pressure-sensitive adhesive sheet having an agent layer was produced. Regarding the obtained multilayer adhesive sheet and surface protective layer, in the same manner as in Example 1, according to the evaluation method shown above, the static friction coefficient was measured, the maximum stress value was measured, the gel fraction was measured, and the solvent resistance was evaluated. The sticking workability was evaluated. The results are shown in Table 2.

(Comparative Example 3)
A multilayer pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the type of the surface protective layer coating liquid was changed to the fluorine-based coating liquid as shown in Table 2. That is, a 50% concentration solution of fluoroethylene vinyl ether in xylene and toluene (100.00 parts of a product name "Lumiflon LF600" manufactured by Asahi Glass Co., Ltd. and an isocyanate crosslinking agent (a product name "Coronate manufactured by Nippon Polyurethane Industry Co., Ltd." HX ") is 9.49 parts, and a dibutyltin lauric acid (trade name" OL1 "manufactured by Tokyo Fine Chemical Co., Ltd.) xylene dilution liquid (solid content concentration is 0.1%) is 0.35 parts as a catalyst. A fluorine-containing coating liquid was prepared by mixing 76.41 parts of toluene as a diluting solvent, and using this fluorine-containing coating liquid, a fluorine-containing surface was formed on one surface of the substrate layer in the same manner as in Example 1. A protective layer was formed, and an adhesive layer was formed on the other surface to prepare a multilayer adhesive sheet. The static friction coefficient, the maximum stress value, the gel fraction, the solvent resistance, and the sticking workability were evaluated in the same manner as in Example 1 according to the evaluation methods described above. It shows in Table 2.

(Comparative example 4)
A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one surface of the base material layer was produced in the same manner as in Example 1 except that the surface protective layer was not provided. With respect to the obtained multilayer adhesive sheet, the static friction coefficient, the maximum stress value, the solvent resistance and the sticking workability were evaluated in the same manner as in Example 1 according to the evaluation methods described above. The results are shown in Table 2.

(Comparative example 5)
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the base material layer was changed to caprolactone-based polyurethane (manufactured by Nippon Matai Co., Ltd.) and no surface protective layer was provided, and the same measurement as in Example 1 was performed. And evaluated. The results are shown in Table 2.

(Notes to Table 1 and Table 2)
F-2954D-5: Carbonate polyurethane emulsion (main ingredient) (Daiichi Kogyo Seiyaku Co., Ltd.)
Superflex 460: Carbonate polyurethane emulsion (main ingredient) (Daiichi Kogyo Seiyaku Co., Ltd.)
Epocros WS-700: Oxazoline crosslinking agent (manufactured by Nippon Shokubai Co., Ltd.)
BYK-349: Leveling agent, polyether modified siloxane (manufactured by Big Chemie Japan Co., Ltd.)
Futegent 100: Leveling agent, sodium perfluoroalkenyloxybenzenesulfonate (manufactured by Neos Co., Ltd.)
Rheolate 216: Thickener (manufactured by Elementis Japan K.K.)
UC-606: Water dispersion type light stabilizer (manufactured by ADEKA Corporation)
UC-3140: Water dispersion type light stabilizer (manufactured by ADEKA Corporation)
LF600: Fluoroethylene vinyl ether alternating copolymer (manufactured by Asahi Glass Co., Ltd.)
"Coronate HX": Isocyanate cross-linking agent (Nippon Polyurethane Industry Co., Ltd.)

  As is clear from Table 1 and Table 2, the multilayer pressure-sensitive adhesive sheets of Examples 1 and 2 of the present invention have higher solvent resistance than the pressure-sensitive adhesive sheets of Comparative Example 1 and Comparative Example 2 in which no crosslinking agent is added. It turned out to be excellent. It is considered that this is because the addition of the crosslinking agent improves the solvent resistance. In order to achieve such effects of the present invention, it is necessary that the surface protective layer contains a cross-linking agent. For example, the cross-linking agent is added in an amount of 5 parts by weight or more based on 100 parts by weight of the base resin of the surface protection layer. The content is preferably 12 parts by weight or less, more preferably 5 parts by weight or more and 11 parts by weight or less, and particularly preferably 5 parts by weight or more and 9 parts by weight or less.

  In addition, the multilayer pressure-sensitive adhesive sheets of Examples 1 and 2 have a smaller maximum stress value in a stretched state of 0% to 10% as compared with the multilayer pressure-sensitive adhesive sheet of Comparative Example 3 having a fluorine-based surface protective layer, and thus have flexibility. It turned out to be excellent.

  Furthermore, it was found that the multilayer pressure-sensitive adhesive sheets of Examples 1 and 2 had a smaller coefficient of static friction and excellent slipperiness as compared with Comparative Example 4 in which the surface protective layer was not provided.

That is, the multilayer pressure-sensitive adhesive sheets of Examples 1 and 2 retain the same flexibility as in Comparative Example 4 of the pressure-sensitive adhesive sheet including only the base material layer and the pressure-sensitive adhesive layer without providing the surface protective layer, and have solvent resistance. It was also found to be excellent in slipperiness.
Therefore, according to the present invention, a multilayer pressure-sensitive adhesive sheet excellent in flexibility, slipperiness, and solvent resistance could be realized.

  INDUSTRIAL APPLICABILITY The multilayer pressure-sensitive adhesive sheet of the present invention can be suitably used as a multilayer pressure-sensitive adhesive sheet that requires flexibility to curved surfaces and the like, and is particularly preferably used also for an adherend having a severe three-dimensional curved surface. You can For example, it can be used as a pressure-sensitive adhesive sheet for protecting the surface of a coating film exposed to harmful environments including outdoor weather, solvents, dust, oils and fats and marine environments, or as a decorative pressure-sensitive adhesive sheet. Further, it is also suitable as a chipping tape for protecting a coating film of an automobile body or the like, an adhesive sheet for a body protection film or a multilayer sheet.

Claims (5)

At least a surface protective layer containing a urethane polymer as a main component, a base material layer containing a polymer composed of only a polyurethane component obtained by reacting one type of polyol and one type of polyisocyanate, and an adhesive layer. The multilayer pressure-sensitive adhesive sheet having, wherein the pressure-sensitive adhesive layer is provided on one surface of the base material layer, and the surface protective layer is provided on the other surface of the base material layer. Contains 50% by weight or more of N, N-dimethylformamide (DMF) insoluble matter, and has a maximum stress value of 0.5 MPa or more and 4.0 MPa or less in a 10% stretched state exceeding 0% of the multilayer adhesive sheet. It is within the range of.   The surface protective layer contains, as a main component, at least one urethane polymer selected from the group consisting of ester-based urethane polymers, ether-based urethane polymers, and ester / acrylic urethane polymers. Item 1. The multilayer adhesive sheet according to Item 1.   The multilayer adhesive sheet according to claim 1 or 2, wherein the urethane-based polymer forming the surface protective layer is a water-based urethane polymer or a solvent-based urethane polymer.   The multilayer adhesive according to any one of claims 1 to 3, wherein the surface protective layer contains a cross-linking agent in an amount of 5 parts by weight or more and 12 parts by weight or less with respect to 100 parts by weight of the urethane polymer. Sheet.   The multilayer pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the multilayer pressure-sensitive adhesive sheet is used as a protective sheet for protecting the surface of an adherend.

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