JP2020050880A - Multi-layer adhesive sheet - Google Patents

Abstract

To provide an adhesive sheet having good solvent resistance, surface slipperiness, and surface followability.SOLUTION: An adhesive sheet contains a surface protective layer, a substrate layer, and an adhesive layer, in which the substrate layer has a multilayer structure positioned between the surface protective layer and the adhesive layer, used for protecting a surface of an adherend, in which thickness of the surface protective layer is 2 to 50 μm, thickness of the substrate layer is 50 to 600 μm, thickness of the adhesive layer is 20 to 100 μm, the surface protective layer contains at least one kind of urethane polymer selected from a group consisting of ester-based urethane polymer, ether-based urethane polymer, and ester/acrylic urethane polymer as a main component, and is a layer containing N,N-dimethylformamide (DMF) insoluble component, the substrate layer is a layer containing a polymer consisting of only a polyurethane component obtained by reacting one kind of polyol and one kind of polyisocyanate, and maximum stress value over 0% to 10% elongation state as the adhesive sheet is 0.5 MPa to 4.0 MPa.SELECTED DRAWING: None

Description

  The present invention relates to a multi-layered pressure-sensitive adhesive sheet, and more particularly to a multi-layered pressure-sensitive adhesive sheet having excellent solvent resistance, surface slippage and curved surface followability.

  For example, in the automobile and aircraft industries, a transparent pressure-sensitive adhesive sheet may be attached in order to prevent a painted surface of a body of an automobile or the like from being damaged. This adhesive sheet requires solvent resistance to be used outdoors, and this adhesive sheet is directly attached to the painted surface by hand using a squeegee or the like. There have been problems such as soiling of the hands, or inability to cleanly adhere to a part having a particularly severe three-dimensional curved surface. 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, in a protective pressure-sensitive adhesive sheet having a coating layer having a good surface slipperiness, followability is deteriorated in a severe part of a three-dimensional curved surface, and it is possible to follow and adhere to an adherend having a three-dimensional curved surface. A difficult problem occurred.

  Further, an adhesive sheet in which a fluorine coat layer is provided on a substrate made of IPN is known (for example, see Japanese Patent Application Laid-Open No. 2001-520127), but it has a curved surface followability for an adherend having a complicated curved surface. From the viewpoint of weather resistance and the like, and an adhesive sheet for protecting a coating film provided with a coating layer made of a fluororesin on a substrate (for example, see JP-A-2009-299053) is also known. However, its flexibility was insufficient, and it was difficult to apply it to complex parts.

JP 2001-520127 A JP-A-2003-96140 JP-A-59-41376 JP 2005-272558 A JP 2009-290553 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 slippage, and curved surface followability.

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

  Here, it is preferable that the surface protective layer contains at least 50% by weight of an N, N-dimethylformamide (DMF) insoluble matter.

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

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

  In the present invention, it is preferable that the surface protective layer contains 5 to 12 parts by weight of a crosslinking agent based on 100 parts by weight of the urethane polymer.

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

  Here, the base layer is preferably a urethane-based polymer or a composite film containing a (meth) acryl-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 multilayer pressure-sensitive adhesive sheet that has excellent solvent resistance, has a curved surface following property, can be stuck neatly even at a site where a three-dimensional curved surface is severe, and has a good surface slipperiness. Can be realized.

It is a schematic diagram for explaining the method of measuring a static friction coefficient. It is explanatory drawing for demonstrating the cross-sectional curve of a three-dimensional curved surface 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) insolubles. In addition, it is preferable that the surface protective layer is disposed on the outermost surface of the multilayer pressure-sensitive adhesive sheet.

  The surface protective layer preferably contains a urethane-based polymer as a main component. For example, the base resin of the surface protective layer is preferably a urethane-based polymer. The urethane polymer is preferably a water-based urethane polymer or a solvent-based urethane polymer. Urethane polymers need to be liquefied for processing or the like. Urethane liquefied using an organic solvent such as toluene is called a solvent-based urethane polymer, and most urethane polymers are organic solvent-based. On the other hand, an aqueous urethane polymer is urethane liquefied using water instead of an organic solvent, and an aqueous urethane polymer is an environmentally friendly material because it can be liquefied without using an organic solvent. It can be said.

  Examples of the water-based urethane polymer preferably used in the present invention include a carbonate-based polymer, a polycarbonate-based polymer, an ester-based polymer, an ether-based polymer, and an ester / acryl-based polymer.

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) 5N / 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. Examples of the ester-based water-based urethane polymer include ADEKA Corporation 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. Examples of the polycarbonate-based aqueous urethane polymer include “HUX-561” (100% modulus, 5 N / mm ² ) and “HUX” manufactured by ADEKA Corporation. -564 "and the like, and examples of the ether-based water-based urethane polymer include trade name" HUX-350 "(100% modulus 25 N / mm ² ) manufactured by ADEKA Corporation and 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 static friction coefficient of the surface protective layer within the range of the present invention can be appropriately selected from these commercially available products. Further, two or more water-based polyurethanes may be used in combination.

  The surface protective layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention preferably contains a crosslinking agent. The content of the crosslinking 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 based on 100 parts by weight of the base resin constituting the surface protective layer. And particularly preferably not less than 5 parts by weight and not more than 9 parts by weight. When the crosslinking agent is contained in an amount of 5 parts by weight or more and 12 parts by weight or less, an appropriate gel fraction can be easily realized.

Crosslinking agents preferably used for the surface protective layer include oxazoline-based crosslinking agents, carbodiimide-based crosslinking agents, epoxy-based crosslinking agents, and the like.
For example, as the oxazoline-based cross-linking agent, trade names "(R) Epocross WS-700" (oxazoline group-containing water-soluble polymer, manufactured by Nippon Shokubai Co., Ltd.), trade names "(R) Epocross WS-500" (Oxazoline And a carbodiimide-based cross-linking agent such as "(R) Carbodilite E-02" (a carbodiimide group-containing water-soluble polymer). Polymer, Nisshinbo Industries, Inc.), trade name “(Registered Trademark) Carbodilite E-01” (carbodiimide group-containing water-soluble polymer, Nisshinbo Industries, Ltd.), and the like. As the epoxy-based cross-linking agent, 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 can further contain additives such as a repellent, a thickener, a light stabilizer, and an ultraviolet absorber. Examples of the repellent (leveling agent) include polyether-modified siloxane, sodium perfluoroalkenyloxybenzenesulfonate, polyester-modified siloxane, and aralkyl-modified siloxane. Examples of the light stabilizer include, for example, aqueous dispersion. Hindered amine light stabilizers and the like, and examples of the ultraviolet absorber include water-dispersed benzotriazole-based ultraviolet absorbers.

  The surface protective layer preferably has a static friction coefficient on the surface of 0.05 to 1.50, more preferably 0.05 to 1.00, and particularly preferably 0.05 to 0.5. When 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), the maximum stress value of the surface protective layer from more than 0% to 100% elongation is preferably 5.0 MPa or more and 24.0 MPa or less, more preferably. Is not less than 10.0 MPa and not more than 20.0 MPa, particularly preferably not less than 12.5 MPa and not more than 17.5 MPa.

  Here, the maximum stress value means that the surface protective layer is subjected to a tensile test at a tensile speed of 200 mm / min, a distance between chucks of 30 mm, 20 ° C., and a thickness of 500 μm to obtain a stress-strain curve. % Means the maximum value of stress per unit area up to the state of elongation (maximum stress value).

  The base material layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention is not particularly limited as long as it has a maximum stress value of more than 0% of the multilayer pressure-sensitive adhesive sheet up to 10% elongation satisfying 0.5 to 4.0 MPa. Although it can be used without being performed, for example, it is preferable to include at least a urethane-based polymer, and it is preferable to use a film made of a urethane-based polymer or a composite film containing a (meth) acrylic-based polymer and a urethane polymer. Here, the urethane-based polymer includes a homopolymer of urethane, a copolymer of urethane and another 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, and more preferably 1.0 MPa or more, over 0% of the base material layer and up to 10% elongation. 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 a tensile test of the base material layer (width 10 mm, length 160 mm) at a pulling speed of 200 mm / min, a distance between chucks of 100 mm, and 23 ° C. to obtain a stress-strain curve. Means the maximum value of stress per unit area (maximum stress value) from 0% to 10% elongation.

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

  Further, the base 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 to the urethane polymer in the composite film is preferably in the range of (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 becomes high, and the workability may be deteriorated. If it exceeds 80/20, flexibility and strength as a film are obtained. May not be possible.

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

  In the present invention, the (meth) acrylic acid monomer is a (meth) acrylic monomer having a carboxyl group, for example, acrylic acid, methacrylic acid, maleic acid, crotonic acid and the like. Of these, acrylic acid is particularly preferred. The content of the (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 below. When the content of the (meth) acrylic acid-based monomer is less than 1% by weight, a long time is required for the reaction, it is very difficult to form a film, and there may be a problem that the strength of the film is not sufficient. . When the content of the (meth) acrylic acid-based monomer exceeds 15% by weight, the water absorption of the film is increased, and a problem may occur in water resistance. When a composite film is used as the substrate, the (meth) acrylic acid-based monomer greatly affects the compatibility with the urethane component and the acrylic component, and is an essential component having a very 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 “(meth) acryl” is displayed like a (meth) acrylic polymer and a (meth) acrylic acid monomer, it is a general term for methacryl and acrylic. Also, even when the word “acryl” is displayed, if there is no problem in general common sense, the concept includes methacryl.
In the present invention, "containing as a main component" means containing 50% by weight or more, preferably 90% by weight or more, and also includes 100% by weight.

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

  In the present invention, it is preferable to use at least one of the group consisting of acryloylmorpholine, isobornyl acrylate, and dicyclopentanyl acrylate as the monofunctional (meth) acrylic monomer having a Tg of 0 ° C. or higher, It is more preferable to use acryloyl morpholine and / or isobornyl acrylate, or acryloyl morpholine and / or dicyclopentanyl acrylate, and 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, more preferably 30% by weight or more and 98% by weight or less in the acrylic component. Is more preferred. If the content of the monofunctional (meth) acrylic monomer is less than 20% by weight, there may be a problem that the strength of the film is not sufficient, and if it exceeds 99% by weight, the rigidity of the film becomes too high and the film becomes brittle. There are cases.

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

  The monofunctional (meth) acrylic monomer having a Tg of less than 0 ° C. may not be contained (the content is 0% by weight), but if contained, the content is more than 0% by weight in the acrylic component. In many cases, it is preferably at most 50% by weight, more preferably more than 0% by weight and at most 45% by weight. When the content of the monofunctional (meth) acrylic monomer exceeds 50% by weight, there may be a problem that the strength of the film is not sufficient.

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

  In the present invention, together with the (meth) acrylic monomer, vinyl acetate, vinyl propionate, styrene, acrylamide, methacrylamide, maleic acid mono- or diesters and derivatives thereof, N-methylolacrylamide, glycidyl acrylate, glycidyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl methacrylamide, 2-hydroxypropyl acrylate, N, N-dimethylacrylamide, N, N-diethylacrylamide, imidoacrylate, 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 types and amounts of the monomers to be copolymerized are appropriately determined in consideration of the characteristics of the composite film and the like.

  Further, other polyfunctional monomers can be added as long as the properties are not impaired. 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, and pentaerythritol Examples thereof include tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, urethane acrylate, epoxy acrylate, and polyester acrylate, and particularly preferably trimethylolpropane tri (meth) acrylate.

  The polyfunctional monomer may be contained 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 the content is 20 parts by weight or less, the elastic modulus does not become too high, and unevenness on the surface of the adherend is reduced. 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 that causes an environmental load such as dibutyltin dilaurate and tin octoate. Can be done.

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

  Examples of high molecular weight diols include polyether polyols obtained by addition polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, and the like, or the above-mentioned dihydric alcohols, 1,4-butanediol, 1,6-hexanediol, and the like. And polyester polyols composed of polycondensates of dihydric base acids 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), polyalkylene carbonate diol (PCD) and the like 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. Epoxy polyols include amine-modified epoxy resins.

  In the present invention, the urethane polymer does not contain a crosslinked structure. The diol used for forming 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 does not form a crosslinked structure is satisfied. That is, the urethane polymer constituting the composite film of the present invention does not include a crosslinked structure, and is therefore 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 an acrylic monomer, reactivity with an isocyanate, and the like. When strength is required, it is effective to increase the amount of urethane hard segments with a low molecular weight diol. When emphasis is placed on 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 depending on the use and purpose, and the characteristics of the base material to be applied, reactivity with isocyanate, compatibility with acrylic, and the like are considered. From these, 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 the 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), 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), butanedi Cyanate, 2,4-hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and the like. Further, dimers and trimers of these and polyphenylmethane diisocyanate are used. Examples of the trimer include an isocyanurate type, a burette type, an allophanate type, and the like, which can be used as appropriate.

  Among these, methylcyclohexane diisocyanate (hydrogenated TDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexane diisocyanate (hydrogenated PPDI), bis (isocyanatomethyl) cyclohexane (hydrogenated XDI), norbornene diisocyanate (NBDI) ), Aliphatic and alicyclic diisocyanates such as isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), butane diisocyanate, 2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate 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 easily generated by a photoreaction, and in the present invention, a benzene ring-free, non-yellowing type, non-yellowing type Modified aliphatic and alicyclic diisocyanates are preferably used.

  These diisocyanates can be used alone or in combination. The type, combination, and the like of the diisocyanate may be appropriately selected from the viewpoint of the properties of the support to which the composite film is applied (applied or the like), the solubility in the acrylic monomer, the reactivity with the hydroxyl group, and the like.

  In the present invention, the urethane-based 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 preferred.

  In the present invention, the amounts of the diol component and the diisocyanate component used to form the urethane polymer are preferably such that the NCO / OH (equivalent ratio) is 1.1 or more and 2.0 or less, and 1.12 or more and 1 or more. .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, the viscosity of the composite film precursor (syrup solution) becomes large, and the work becomes difficult in the subsequent sheeting step. There is. On the other hand, when NCO / OH (equivalent ratio) exceeds 2.0, the molecular weight of the urethane polymer decreases, and the breaking strength tends to decrease.

  In the present invention, the ratio of the acrylic component to the urethane component forming the composite film is such that the weight ratio of the acrylic component / urethane component is from 0.25 to 4.00, preferably from 0.4 to 2, 0.4 or less, particularly preferably 0.5 or more and 1.9 or less. If the ratio of the acrylic component / urethane component is less than 0.25, the viscosity of the syrup solution increases, and the work may be difficult in the subsequent sheeting step. When the ratio of the acrylic component / urethane component exceeds 4.00, the amount of the urethane polymer in the composite film becomes less than 25%, the tensile strength at break decreases, and the composite film may not be practically usable.

  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 into the molecular end of the urethane prepolymer, and the copolymerizability with the (meth) acrylic monomer is imparted. And the SS characteristics such as breaking strength can be improved. As the hydroxyl group-containing acrylic monomer used here, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate and the like are used. The amount of the hydroxyl group-containing acrylic monomer to be 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, commonly used additives such as an ultraviolet absorber, an antioxidant, an antioxidant, a filler, a pigment, a colorant, a flame retardant, an antistatic agent, a light stabilizer, and the like. It can be added within a range that does not inhibit the effects of the present invention. These additives are used in usual amounts depending on the type. These additives may be added in advance before the polymerization reaction of the diisocyanate and the diol, or may be added before each of the urethane polymer and the acrylic monomer is polymerized.

As the ultraviolet absorber (UVA) used in the present invention, for example, 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (for example, Ciba Japan) as a benzotriazole-based ultraviolet absorber Made in "TINUVIN PS"), and benzenepropanoic acid 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy _(side chain and straight of C 7 -C ₉ Ester compound (for example, “TINUVIN 384-2” manufactured by Ciba Japan) with 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- 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 Co., Ltd., TINUVIN 1130 ”), 2- (2H-benzotriazol-2-yl) -p-cresol (for example,“ TINUVIN P ”, Ciba Japan Co., Ltd.), 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-tetrahydrophthalimide-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 hydroxyphenyltriazine-based ultraviolet absorber include 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hydroxyphenyl and [ Reaction product with (C10 to C16, mainly C12 to C13 alkyloxy) methyl] oxirane (for example, "TINUVIN 400" manufactured by Ciba Japan), 2- (2,4-dihydroxyphenyl) -4,6 Reaction product of -bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester (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 (eg, "TINUVIN 479" manufactured by Ciba Japan Co., Ltd.).

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

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

  The total amount of the ultraviolet absorber is preferably from 0.1% by weight to 4.0% by weight, and more preferably from 0.5% by weight to 2.0% by weight, based on 100% by weight of the film precursor. It is more preferred that: When the content of the ultraviolet absorber is 0.1% by weight or more, absorption of ultraviolet light causing deterioration and coloring is sufficient, and when the content is 4.0% by weight or less, 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 One-to-one reaction product with diamine (eg, “TINUVIN 119” manufactured by Ciba Japan), 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, Ciba Japan "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 a mixture of methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (for example, “TINUVIN manufactured by Ciba Japan Co., Ltd.) 65 "), bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (for example," TINUVIN 770 "manufactured by Ciba Japan), bis (2,2,6,6- Reaction product of tetramethyl-1- (octyloxy) -4-piperidinyl) ester (1,1-dimethylethyl hydroperoxide) with 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] butylmalonate (for example, manufactured by Ciba Japan) "TINUVIN 144"), cyclohexane and N-butyl peroxide-2,2,6,6-tetramethyl-4-piperidinamine-2,4,6-trichloro-1, Reaction product with 2,5-triazine and 2-aminoethanol (for example, “TINUVIN 152” manufactured by Ciba Japan), bis (1,2,2,6,6-pentamethyl-4-) Mixtures 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 a solvent may be added for adjusting the viscosity of coating. The solvent can be appropriately selected from commonly used solvents, and examples thereof include ethyl acetate, toluene, chloroform, dimethylformamide and the like.

  In the present invention, the composite film, for example, using an acrylic monomer as a diluent, reacts 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 coated on a support (which has been peeled off if necessary), etc., and depending on the type of photopolymerization initiator, etc., ionization of α rays, β rays, γ rays, neutron rays, electron beams, etc. A composite film can be formed by irradiating radiation such as sexual radiation or ultraviolet light, visible light, or the like, and curing, and then peeling and removing the support and the like. Alternatively, the composite film may be obtained by laminating a composite film on a support or the like without removing and removing the support or the like.

  Specifically, after dissolving the diol in the acrylic monomer, diisocyanate or the like is added and reacted with the diol to adjust the viscosity, and this is peeled off on a support or the like or, if necessary, on the support or the like. After coating on the treated surface, the composition is cured using a low-pressure mercury lamp or the like, whereby a composite film can be obtained. In this method, the acrylic monomer may be added at once during the urethane synthesis, or may be added in several portions. After dissolving the diisocyanate in the acrylic monomer, the diol may be reacted. According to this method, the molecular weight is not limited, and a polyurethane having a high molecular weight can be produced. Therefore, the molecular weight of urethane finally obtained can be designed to an arbitrary size.

  At this time, in order to avoid polymerization inhibition by 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 filled with an inert gas. The oxygen concentration may be lowered by placing a substrate in a container prepared.

  In the present invention, the type of radiation and the like and the type of lamp used for irradiation can be appropriately selected, and a low-pressure lamp such as a fluorescent chemical lamp, a black light, and a germicidal lamp; 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 film characteristics. 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 be caused.

  Further, the temperature at the time of irradiating ultraviolet rays or the like is not particularly limited and can be arbitrarily set.However, if the temperature is too high, a termination reaction due to heat of polymerization is likely to occur, which is likely to cause a deterioration in characteristics. The temperature is usually 70 ° C. or lower, preferably 50 ° C. or lower, and more preferably 30 ° C. or lower.

  The mixture containing a urethane polymer and an acrylic monomer as main components contains a photopolymerization initiator. The photopolymerization initiator can be used without any particular limitation. Examples thereof include a ketal-based photopolymerization initiator, an α-hydroxyketone-based photopolymerization initiator, an α-aminoketone-based photopolymerization initiator, and an acylphosphine oxide-based photopolymerization initiator. Polymerization initiator, bezophenone photopolymerization initiator, thioxanthone photopolymerization initiator, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photoactive oxime photopolymerization initiator Benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators and the like can be used.

  As the ketal-based photopolymerization initiator, for example, 2,2-dimethoxy-1,2-diphenylethan-1-one (a commercially available product is “Irgacure 651” manufactured by Ciba Specialty Chemicals, Inc.) Etc.).

  Examples of the α-hydroxyketone-based photopolymerization initiator include 1-hydroxycyclohexylphenylketone (commercially available ones such as “Irgacure 184” manufactured by Ciba Japan) and 2-hydroxy-2- Methyl-1-phenylpropan-1-one (commercially available, such as "Darocur 1173" manufactured by Ciba Japan) and 1- [4- (2-hydroxyethoxy) -phenyl] -2. -Hydroxy-2-methyl-1-propan-1-one (as commercially available products, such as "Irgacure 2959" manufactured by Ciba Japan) and the like.

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

  As the acylphosphine oxide-based photopolymerization initiator, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (a commercially available product such as "Lucillin TPO" manufactured by BASF) is exemplified.

  Examples of the benzoin ether-based photopolymerization initiator include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, anisole Methyl ether and the like can be mentioned.

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

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

  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, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenyl ketone, and the like.

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

  The thickness of the surface protective layer constituting the multilayer pressure-sensitive adhesive sheet of the present invention is preferably from 2 to 50 μm, more preferably from 5 to 40 μm, and still more preferably from 8 to 30 μm. If the thickness of the surface protective layer is less than 2 μm, a defect site where the surface protective layer is not formed, such as a pinhole, is likely to occur, and the characteristics of the surface protective layer may not be sufficiently exhibited. If it exceeds 50 μm, the physical properties of the surface protective layer may lower 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 according to the purpose and the like, for example, depending on the type and location of the object to be covered and protected, and is not particularly limited. Is more preferable, and it is more preferable that it is 140 micrometers or more. Further, the upper limit of the thickness is preferably about 1 mm. For example, the thickness of the base material layer is preferably about 50 to 800 μm, more preferably about 100 to 600 μm in the case of chipping applications used for protecting the body of an automobile. In the case of aircraft use, it is about 50 to 1,000 μm, more preferably about 200 to 800 μm. In the case of motorcycle use, it is preferably about 50 to 800 μm, more preferably about 100 to 600 μm.

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

  Alternatively, for example, a coating solution for a surface protective layer is applied on a PET film that has been subjected to a release treatment, and dried to form a surface protective layer. A layered product (multilayer sheet) can be obtained by applying a coating liquid for a composite film containing an acrylic monomer and a urethane polymer on this surface protective layer and irradiating it with ultraviolet rays or the like to cure it.

  In the present invention, in the multilayer sheet, other films can be laminated on the base material layer within a range that does not impair the effects of the present invention. Examples of a material for forming another film include a polyester resin such as polyethylene terephthalate (PET), a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a polyimide (PI), and a polyetheretherketone (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. And thermosetting resins.

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

  The pressure-sensitive adhesive forming this pressure-sensitive adhesive layer is not particularly limited, and acrylic, rubber, and silicone-based general adhesives can be used. Considering cost and the like, an acrylic pressure-sensitive adhesive is preferable.

  As the acrylic pressure-sensitive adhesive, an acrylic copolymer obtained by copolymerizing a monomer component mainly containing an acrylate ester with a monomer component having a functional group such as a carboxyl group or a hydroxyl group (two or more types may be used) An acrylic pressure-sensitive adhesive containing

  Examples of the acrylate 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, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, Sil (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl ( (Meth) acrylate, eicosyl (meth) acrylate, isobornyl (meth) acrylate, 1-adamantyl (meth) acrylate and the like. One or more of these alkyl (meth) acrylates can be used.

  The following monomer components can be copolymerized with the above alkyl (meth) acrylate. Examples of the copolymerizable monomer component include monomers having 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, and (4-hydroxymethylcyclohexyl) -methyl acrylate; glycidyl (meth) acrylate, methyl glycidyl (meth) Acri Glycidyl group-containing monomers such as acrylates; 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, NA 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 after being copolymerized 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 preferred to include. That is, the pressure-sensitive adhesive used in the present invention can use a copolymer obtained by copolymerizing a carboxyl group-containing monomer such as 2-ethylhexyl acrylate or isononyl acrylate as a main monomer and acrylic acid or methacrylic acid. .

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

  In the present invention, the pressure-sensitive adhesive layer is, for example, a method in which a solvent-based or emulsion-based pressure-sensitive adhesive is directly applied to a substrate layer and dried, and the pressure-sensitive adhesive is applied to release paper to form a pressure-sensitive adhesive layer in advance. In addition, a method of bonding this pressure-sensitive adhesive layer to a base material layer or the like can be applied. A method of applying a radiation-curable pressure-sensitive adhesive to a base material layer and irradiating the pressure-sensitive adhesive layer and the film with radiation to simultaneously cure and form the base material layer and the pressure-sensitive adhesive layer can also be applied. it can.

In the present invention, the static friction coefficient of the multilayer pressure-sensitive adhesive sheet is determined by measuring the static friction coefficient of the outermost 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 a normal force (uniform pressure distribution) to measure a maximum load. Then, the static friction coefficient is obtained using the following calculation formula.
μ = Fs / Fp
(Μ: static friction coefficient, Fs: static friction force (N), Fp: normal force)

  In the multilayer pressure-sensitive adhesive sheet of the present invention, the maximum stress value of the multilayer pressure-sensitive adhesive sheet from 0% to a 10% elongation state needs to be 0.5 to 4.0 MPa, preferably 1.0 MPa or more. 0.0 MPa or less, 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 from 0% to 10% elongation is 0.5 to 4.0 MPa, good curved surface followability can be achieved. On the other hand, if the maximum stress value is too low (for example, less than 0.5 MPa), the handleability (ease of handling the tape) when attaching to a large-area adherend is reduced.

  Here, the maximum stress value refers to a stress-strain curve obtained by conducting a tensile test on a multilayer adhesive sheet (width 10 mm, length 160 mm) at a tensile speed of 200 mm / min, a distance between chucks of 100 mm, and 23 ° C. It refers to the maximum value of stress per unit area (maximum stress value) from 1% to 10% elongation.

  The multi-layered pressure-sensitive adhesive sheet of the present invention is required to be transparent in order to reflect the color and the like of the coated surface of the adherend as it is to the appearance, but using a pigment or the like, the same color as the color of the coated surface is used. It may be colored or colored in another color and used as a paint-substituting adhesive sheet.

  In the multilayer pressure-sensitive adhesive sheet of the present invention, an application sheet can be used for improving the bonding operation of the pressure-sensitive adhesive sheet, for example, for positioning for bonding.

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

  Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. In the following examples, “parts” means “parts by weight” and “%” means “% by weight” unless otherwise specified. The measurement method and evaluation method used in the following examples are shown below.

(Measurement method and evaluation method)
(1) Measurement of maximum stress value The multilayer pressure-sensitive adhesive sheet was cut into a width of 10 mm x a length of 160 mm, a tensile test was performed at a tensile speed of 200 mm / min, a distance between chucks of 100 mm, and 23 ° C to determine a stress-strain curve. . The maximum value of the stress per unit area (maximum stress value) when the multilayer pressure-sensitive adhesive sheet was stretched from 0% to 10% was determined.

(2) Measurement of Static Friction Coefficient The multilayer pressure-sensitive adhesive sheet was cut into a size of 80 mm in width × 100 mm in length, and the multilayer pressure-sensitive adhesive sheet was stuck on a standard test plate (JISG3141: manufactured by Nippon Test Panel Co., Ltd.). A slide was placed on the adhesive sheet, and the static friction coefficient of the outermost layer (ex. Surface protective 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 stuck on the contact surface of the sliding piece with the adhesive sheet surface, and the sliding speed was 100 mm / min. The measurement was performed by pulling the slide under the conditions. The static friction coefficient was determined 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 the mass of the sliding piece (= 9.8 N / kg × 0.2 kg))

  FIGS. 1A and 1B are schematic diagrams for explaining a method of measuring a static friction coefficient. As shown in FIG. 1A, the sample 1 is fixed to the counterpart material 2 so that the measurement surface of the sample 1 (ex. The multilayer adhesive sheet) faces upward, that is, for example, the adhesive layer of the multilayer adhesive sheet. Is adhered and fixed on a mating material 2 (ex. Standard test plate), a sliding piece (contact area 63 mm × 63 mm) is arranged on the measurement surface of the sample 1, and the sliding 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) to apply a uniform pressure distribution. The sample 1 may be fixed directly to the mating member 2 or may be fixed 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 and provides friction, reaching a 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 (30 mm in width and 50 mm in length) was attached to a black panel (KINO-1210TW: manufactured by Kansai Paint Co., Ltd.), and the multilayer pressure-sensitive adhesive was impregnated with ethanol. The sheet surface was rubbed 20 times and then the multilayer pressure-sensitive adhesive sheet was evaluated in two steps. The evaluation was performed based on the following evaluation criteria.

(Evaluation criteria)
○ No turbidity (dissolution) of the multilayer adhesive sheet was observed.
C: Cloudiness (dissolution) of the multilayer pressure-sensitive 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. Thereafter, the SUS mesh covering 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 equation.
(Calculation formula)
Gel fraction (%) = {(weight of surface protective layer after immersion and drying) / (weight of surface protective layer before immersion and drying)} × 100

(5) Evaluation of sticking workability Three-dimensional curved surface portion (size: 300 mm in length x 210 mm in width, curvature: cross section curve composed of maximum convex curvature (R = 43.3), maximum concave curvature (R = 34.6)) (A site having a curved surface including (see FIG. 2)) a laminating operation of laminating a multilayer adhesive sheet was performed to evaluate laminating workability. That is, each of "surface slipperiness" and "curved surface following property" was evaluated by a score (1 to 4 points), and the total score of both was obtained. However, there were three stickers who participated in the test. The criteria for scoring "Surface slipperiness" and "Surface followability" were 4 points for a very good level, 3 points for a problem-free level, 2 points for a level requiring slight improvement, and a level for improvement. Is taken as one point, and is shown as an average value of three workers.

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

(Evaluation criteria):
"Excellent" A total of 5 points or more in sticking workability
"Good" The total score of the pasting workability is larger than 4.5 points and less than 5 points. "Poor" The total score of the pasting workability is 4.5 points or less.

  If “good” is indicated in the above evaluation criterion, if the curved surface following ability is poor, the work of pressing strongly with a squeegee or the work of rubbing with a squeegee many times increases, and the working efficiency is slightly reduced. Further, if the curved surface followability is poor, the work of pulling and repeating the work, that is, the work of peeling off the once pasted portion and pasting it again increases, and the working efficiency is slightly lowered. In addition, if the slipperiness is poor, the squeegee is likely to have streaks or scratches when pasting, and it is necessary to work carefully, so that the working efficiency is reduced.

  When the evaluation criteria are indicated as "poor", if the surface slippage is poor, the squeegee will not slide smoothly, and it will be difficult to remove remaining air bubbles and water bubbles. Further, if the surface slippage is poor, the squeegee will bite when pasting, so that streaks and scratches are apt to be made and defects are apt to occur. In addition, when the curved surface following property is poor, air bubbles and water bubbles are apt to remain, and problems are apt to occur. Further, if the curved surface following property is poor, the excess material (the portion that does not fit the curved surface) increases.

(Example 1)
<< Preparation of coating solution for surface protective layer >>
55.88 parts of an aqueous urethane polymer (carbonate-based polyurethane emulsion (main agent), trade name “F-2954D-5” manufactured by Daiichi Kogyo Chemical Co., Ltd.) as a coating solution for the surface protective layer, and an aqueous urethane polymer (first) 44.12 parts of a carbonate-based polyurethane emulsion (main agent) manufactured by Kogyo Chemical Co., Ltd. (trade name: “Superflex 460”), and 5 (Epocross WS-700) (manufactured by Nippon Shokubai Co., Ltd.) as an oxazoline cross-linking agent. 81 parts, 0.1 part of a polyether-modified siloxane (trade name "BYK-349", manufactured by BYK-Chemie-Japan Co., Ltd.) as a leveling agent and sodium perfluoroalkenyloxybenzenesulfonate (trade name "Fugent 100 (1% diluted solvent), 1.00 part by Neos Co., Ltd. 1.00 part of trade name "Leorate 216" (manufactured by Elementis Japan KK) as a viscosity agent, 0.80 part of trade name "UC-606" (manufactured by ADEKA Corporation) as an aqueous dispersion type light stabilizer, and As a water-dispersed benzotriazole-based ultraviolet absorber, trade name “UC-3140” (manufactured by ADEKA Corporation) was mixed at a ratio of 0.20 part. Next, the mixture was stirred at a rotation speed of 2000 rpm for 10 minutes using a disper, and then defoamed using a defoaming apparatus (2000 rpm, 10 min) to prepare a coating solution for a surface protective layer. In addition, the maximum stress value of the surface protective layer using this coating solution from 0% to 100% elongation was 6.45 MPa (calculated value), and is shown in Table 1.

《Formation of surface protective layer》
An adipate / ester thermoplastic polyurethane film (manufactured by Nippon Matai Co., Ltd., hardness: 86A) having a thickness of 140 μm was used as the base material layer. On this adipate-based thermoplastic polyurethane film (adipate-based TPU film), the prepared coating solution for a surface protective layer is applied so as to have a cured thickness of 10 μm, and dried and cured at a temperature of 140 ° C. for 3 minutes. Thus, 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, 0.07 part of a trade name “Irgacure 651” (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and After mixing 0.07 parts of the name "Irgacure 184" (manufactured by Ciba Specialty Chemicals), until the viscosity becomes about 15 Pa · s (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.). Irradiation with ultraviolet light produced an acrylic composition (UV syrup) that was partially polymerized.

  To 100 parts of the obtained UV syrup, 0.3 parts of hexanediol diacrylate was added to prepare an adhesive composition.

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

A PET film that had been subjected to a release treatment was applied thereon as a separator, and the PET film was cured by irradiating the surface of the PET film with ultraviolet rays (illuminance: 290 mW / cm ² , light amount: 4,600 mJ / cm ² ) using a metal halide lamp. Thus, an adhesive layer was formed on the release liner. Then, it dried at 140 degreeC for 3 minute (s), dried the unreacted residual acrylic monomer, and produced the adhesive layer.

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

《Measurement and evaluation》
With respect to the obtained multilayer pressure-sensitive adhesive sheet, the maximum stress value in the range from more than 0% to 10% elongation was determined according to the evaluation method described above, solvent resistance was evaluated, and the workability of application was evaluated. . Furthermore, the static friction coefficient and the gel fraction of the obtained surface protective layer were measured. Table 2 shows the results.

(Example 2)
As shown in Table 1, the amount of the coating solution for the surface protective layer was 45.78 parts for the product name "F-2954D-5", 54.22 parts for the product name "Superflex 460", and the product name "Epocross WS". -700 ”, 5.81 parts, trade name“ BKY-349 ”0.1 parts, trade name“ Fugent 100 (1% diluting solvent) ”1.00 parts, trade name“ Rheolate 216 ”1. 00 parts, the trade name "UC-606" was changed to 0.80 parts, and the trade name "UC-3140" was changed to a mixing ratio of 0.20 parts, in the same manner as in Example 1, except for one of the base material layers. 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. For the obtained multilayer pressure-sensitive adhesive sheet and surface protective layer, in the same manner as in Example 1, in accordance with the evaluation method described above, measurement of static friction coefficient, measurement of maximum stress value, measurement of gel fraction, evaluation of solvent resistance, The workability of sticking was evaluated. Table 2 shows the results.

(Comparative Example 1)
As shown in Table 1, the blending amount of the coating solution for the surface protective layer was 55.88 parts for the trade name "F-2954D-5", 44.12 parts for the trade name "Superflex 460", and the trade name "BKY- 349 ", 1.00 parts of trade name" Fugent 100 (1% diluting solvent) ", 1.00 parts of trade name" Leolate 216 ", and 0.80 trade name of" UC-606 " Part, the trade name “UC-3140” was changed to the mixing ratio of 0.20 part, and the same procedure as in Example 1 was carried out except that the base material layer had a surface protective layer on one surface and the other surface had an adhesive. A multilayer pressure-sensitive adhesive sheet having an agent layer was produced. For the obtained multilayer pressure-sensitive adhesive sheet and surface protective layer, in the same manner as in Example 1, in accordance with the evaluation method described above, measurement of static friction coefficient, measurement of maximum stress value, measurement of gel fraction, evaluation of solvent resistance, The workability of sticking was evaluated. Table 2 shows the results.

(Comparative Example 2)
As shown in Table 1, the amount of the coating solution for the surface protective layer was 45.78 parts for the product name “F-2954D-5”, 54.22 parts for the product name “Superflex 460”, and the product name “BKY- 349 ", 1.00 parts of trade name" Fugent 100 (1% diluting solvent) ", 1.00 parts of trade name" Leolate 216 ", and 0.80 trade name of" UC-606 " Part, the trade name “UC-3140” was changed to the mixing ratio of 0.20 part, and the same procedure as in Example 1 was carried out except that the base material layer had a surface protective layer on one surface and the other surface had an adhesive. A multilayer pressure-sensitive adhesive sheet having an agent layer was produced. For the obtained multilayer pressure-sensitive adhesive sheet and surface protective layer, in the same manner as in Example 1, in accordance with the evaluation method described above, measurement of static friction coefficient, measurement of maximum stress value, measurement of gel fraction, evaluation of solvent resistance, The workability of sticking was evaluated. Table 2 shows the results.

(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 coating solution for the surface protective layer was changed to a fluorine-based coating solution as shown in Table 2. That is, a 50% concentration solution of fluoroethylene vinyl ether in xylene and toluene (100.00 parts of "Lumiflon LF600" manufactured by Asahi Glass Co., Ltd.) and an isocyanate-based cross-linking agent ("Coronate" manufactured by Nippon Polyurethane Industry Co., Ltd.) HX "), 9.49 parts, and 0.35 parts of a xylene diluent (solid content: 0.1%) of dibutyltin lauric acid (trade name" OL1 "manufactured by Tokyo Fine Chemical Co., Ltd.) as a catalyst. A fluorine-based coating solution was prepared by mixing 76.41 parts of toluene as a diluting solvent, and using this fluorine-based coating solution, a fluorine-based surface was applied to one surface of the base material layer in the same manner as in Example 1. A protective layer was formed, and a pressure-sensitive adhesive layer was formed on the other surface to prepare a multilayer pressure-sensitive adhesive sheet. According to the evaluation method described above, the measurement of the coefficient of static friction, the measurement of the maximum stress value, the measurement of the gel fraction, the evaluation of the solvent resistance, and the evaluation of the sticking workability were performed in the same manner as in Example 1. It is shown in Table 2.

(Comparative Example 4)
A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one surface of a substrate layer was prepared in the same manner as in Example 1 except that the surface protective layer was not provided. In the same manner as in Example 1, the obtained multilayer pressure-sensitive adhesive sheet was subjected to the measurement of the static friction coefficient, the measurement of the maximum stress value, the evaluation of the solvent resistance, and the evaluation of the sticking workability in accordance with the evaluation methods described above. Table 2 shows the results.

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

(Notes for Tables 1 and 2)
F-2954D-5: carbonate-based polyurethane emulsion (base agent) (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
Superflex 460: carbonate-based polyurethane emulsion (base) (Daiichi Kogyo Seiyaku Co., Ltd.)
Epocros WS-700: Oxazoline-based cross-linking agent (Nippon Shokubai Co., Ltd.)
BYK-349: Leveling agent, polyether modified siloxane (manufactured by BYK Japan KK)
Phantagent 100: Leveling agent, sodium perfluoroalkenyloxybenzenesulfonate (manufactured by Neos Corporation)
Leorate 216: thickener (manufactured by Elementis Japan KK)
UC-606: Water-dispersed light stabilizer (made 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-based crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd.)

  As is clear from Tables 1 and 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 Examples 1 and 2 to which no crosslinking agent is added. It turned out to be excellent. This is considered to be due to the fact that the addition of the crosslinking agent improves the solvent resistance. In order to realize such effects of the present invention, it is necessary that the surface protective layer contains a crosslinking agent. For example, the crosslinking agent is not less than 5 parts by weight based on 100 parts by weight of the base resin of the surface protective 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, 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% than the multilayer pressure-sensitive adhesive sheet of Comparative Example 3 having a fluorine-based surface protective layer, and 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 static friction coefficient and were superior in slipperiness as compared with Comparative Example 4 in which no surface protective layer was provided.

That is, the multilayer pressure-sensitive adhesive sheets of Examples 1 and 2 maintain the same flexibility as Comparative Example 4 of the pressure-sensitive adhesive sheet comprising only the base material layer and the pressure-sensitive adhesive layer without providing the surface protective layer, and have the solvent resistance. And it turned out that it is excellent in slipperiness.
Therefore, according to the present invention, a multilayer pressure-sensitive adhesive sheet excellent in all of flexibility, slipperiness and solvent resistance was able to be realized.

  The multilayer pressure-sensitive adhesive sheet of the present invention can be suitably used as a multilayer pressure-sensitive adhesive sheet requiring flexibility to curved surfaces and the like, and is particularly suitably used for adherends having severe three-dimensional curved surfaces. Can be. 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 a marine environment or 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 or a multilayer sheet for a body protection film.

Claims (6)

Wherein the front surface protective layer and the substrate layer and the adhesive layer has a multilayered structure in which the base layer is located between the adhesive layer and the surface protective layer to protect the surface of the adherend Adhesive sheet used for
The thickness of the surface protective layer is 2 to 50 μm,
The thickness of the base material layer is 50 to 600 μm,
The thickness of the pressure-sensitive adhesive layer is 20 to 100 μm,
The surface protective layer contains, as a main component, at least one urethane polymer selected from the group consisting of an ester urethane polymer, an ether urethane polymer, and an ester / acrylic urethane polymer ; A layer containing N-dimethylformamide (DMF) insoluble matter ,
The base material layer is a layer containing a polymer consisting of only a polyurethane component obtained by reacting one kind of polyol and one kind of polyisocyanate,
Examples adhesive sheet, the maximum stress value at from 0% to 10% stretched state over, characterized in that 0.5MPa or more, within the following 4.0 MPa, viscosity adhesive sheet. The pressure-sensitive adhesive sheet according to claim 1, wherein the maximum stress value is in a range from 0.5 MPa to 3.0 MPa. 3. The pressure-sensitive adhesive layer according to claim 1, wherein the pressure-sensitive adhesive layer is a layer containing, as a main component, at least one type of pressure-sensitive adhesive selected from the group consisting of an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, and a silicon-based pressure-sensitive adhesive. 4. Adhesive sheet. Polyurethane constituting the polymer consisting only of the polyurethane component, adipate ester-based thermoplastic polyurethane, polycaprolactone-based thermoplastic polyurethane, polyether-based thermoplastic polyurethane, and at least selected from the group consisting of polycarbonate-based thermoplastic polyurethane The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, which is one type. The urethane polymer in the surface protective layer is a water-based urethane polymer or solvent-based urethane polymer, viscosity adhesive sheet according to 請 Motomeko 1-4. The pressure-sensitive adhesive sheet according to claim 1, wherein the surface protective layer contains at least 50% by weight of an N, N-dimethylformamide (DMF) -insoluble component.

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