JP2006002143A - Adhesive sheet and decorative adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative adhesive sheet which has little environmental load when burned or discarded, has a sufficient tear strength, is excellent in applicability to a curved surface etc. and is excellent in weather resistance. <P>SOLUTION: The adhesive sheet has an adhesive layer stacked on a substrate sheet, wherein the substrate sheet comprises an acrylic urethane copolymer obtained by reacting a vinyl compound containing at least one (meth)acrylate with a high-molecular linear polyurethane prepolymer having ethylenically unsaturated double bond groups at both ends. The high-molecular linear polyurethane prepolymer has a weight average molecular weight within the range of 10,000 to 1,000,000, and the weight ratio of the high-molecular linear polyurethane prepolymer to the vinyl compound is within the range of 60:40 to 30:70. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adhesive sheet used indoors and outdoors.

  Adhesive sheets are used for decoration as outdoor or indoor advertising stickers or display stickers. Conventional pressure-sensitive adhesive sheets are generally constituted by using a vinyl chloride resin film as a base material and forming a pressure-sensitive adhesive layer on one side of the base material. However, when a vinyl chloride film is used as a base material, chlorine gas and hydrogen chloride gas are generated during incineration and disposal, and thus an environmental burden cannot be avoided (see, for example, Patent Document 1).

  Therefore, in recent years, a method for reducing the burden on the environment by using an acrylic resin film as a base material has been proposed (see, for example, Patent Document 2).

  However, since the tear strength is weaker than that of a pressure-sensitive adhesive sheet using a conventional vinyl chloride resin film as a base material, handling in the case of curved surface construction was poor.

  In addition, when constructing a decorative adhesive sheet, the original sheet is cut into the required shape and unnecessary parts are removed on the release paper. There was a problem that it was necessary to redo the work of turning the sheet, or the necessary parts were torn together and the entire sheet could not be used. Also, as another construction, if the unnecessary part is peeled off after the sheet is first applied to the adherend, the adhesion between the adherend and the sheet is strong. There was a problem that it was easy to tear.

Furthermore, at the stage where the acrylic resin film is formed by the casting method, the film tends to have dust and the like in the production line environment, which may cause poor appearance. For this reason, it was necessary to produce the film on a film forming line with a high degree of cleanliness.
Japanese Patent Laid-Open No. 5-078626 Japanese Patent Laid-Open No. 5-043845

  The present invention has been made to solve the above-described problems relating to the conventional pressure-sensitive adhesive sheet, and the object thereof is to provide a pressure-sensitive adhesive sheet having excellent tear strength, and is environmentally friendly and has high weather resistance. Another object of the present invention is to provide a pressure-sensitive adhesive sheet that can be produced even in a production environment with a low degree of cleanness.

  The present invention will be described in detail below.

  The pressure-sensitive adhesive sheet of the present invention is obtained by reacting a polymer linear polyurethane prepolymer having an ethylenically unsaturated double bond group at both ends with a vinyl compound containing at least one (meth) acrylic ester. A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a base sheet made of an acrylic urethane copolymer, wherein the polymer linear polyurethane prepolymer has a weight average molecular weight in the range of 17,000 to 100,000, The weight ratio between the linear polyurethane prepolymer and the vinyl compound is in the range of 60/40 to 30/70.

  Further, in a specific aspect of the pressure-sensitive adhesive sheet according to the present invention, an unsaturated carboxylic acid ester is added at a ratio of 0.1 to 10.0% by weight with respect to 100% by weight of the base sheet, and is added to JIS K7128. The tear load by the prescribed trouser tear method is 170 mN or more, and the 2% tensile stress of the film is in the range of 4 to 20 N / 15 mm.

  Although the adhesive sheet which concerns on this invention is used for various uses, it is used suitably as an adhesive sheet for decoration.

  The present invention is described in further detail below.

  The acrylic urethane copolymer used for the base sheet of the present invention is a polymer linear polyurethane prepolymer having an ethylenically unsaturated group double bond group at both ends and a weight average molecular weight of 10,000 to 100,000. , A copolymer obtained by reacting a vinyl compound containing at least one (meth) acrylic acid ester, and basically obtained according to the method described in JP-A-10-1524 Can do. That is, such an acrylic urethane copolymer has a step of producing a polymer linear polyurethane prepolymer having both terminal ethylenically unsaturated double bond groups, and at least one (meta) in the presence of the prepolymer. ) It can be obtained by two steps such as a step of polymerizing a vinyl compound having an acrylate group. Moreover, it is preferable that the weight average molecular weight of the acrylic urethane copolymer used by this invention is the range of 15000-150000.

  First, a polymer linear polyurethane prepolymer having an ethylenically unsaturated double bond group is produced in the first step. (Meth) acrylic acid comprising a polymer linear urethane segment having NCO groups at both ends in the weight average molecular weight range of 10,000-100,000 and then containing one hydroxyl group capable of reacting with NCO at both ends It consists of adding a theoretical amount of ester. In order to synthesize this polymer linear polyurethane prepolymer, it is only necessary to follow a general method, that is, a long-chain diol, a short-chain glycol, and a chain extender depending on the case. What is necessary is just to add and react the theoretical amount of organic diisocyanate with respect to molecular weight. This reaction is performed in an inert organic solvent, and a metal catalyst or a tertiary amine catalyst can be used to accelerate the reaction.

  In the second step, a vinyl compound containing at least one (meth) acrylic acid ester is added to the polyurethane prepolymer having ethylenically unsaturated double bond groups at both ends synthesized in the first step, and radicals are added. In the presence of the generator, an acrylic urethane copolymer is synthesized by conducting a radical polymerization reaction of a vinyl compound starting from both terminal unsaturated double bonds of the polymer linear polyurethane prepolymer in an organic solvent. This reaction may be radical polymerization performed under the addition of a radical generator, which is a general technique for acrylic resin polymerization. At this time, the polymerization degree of acrylic can also be adjusted by appropriately adding a thiol group-containing compound as a chain transfer agent to the reaction solution.

  Specific examples of the organic diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, 4,4-diphenylmethane diisocyanate, 2 , 4-diphenylmethane diisocyanate, 4,4-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4-diisocyanate, 2,2-diphenylpropane-4,4-diisocyanate, 3,3-dimethyldiphenylmethane-4,4-diisocyanate, 4,4-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3- Aromatic diisocyanates such as methoxydiphenyl-4,4-diisocyanate, aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, aliphatics such as isophorone diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenation And alicyclic diisocyanates such as xylene diisocyanate and hydrogenated diphenylmethane diisocyanate. Among them, alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, and hydrogenated xylene diisocyanate having an asymmetric structure are preferable because they are excellent in weather resistance and prevent crystallization of urethane segments.

  As the long-chain diol, those known in the polyurethane industry are used, and examples thereof include polyester diol, polyester amide diol, polyether diol, polyester / polyether diol, and polycarbonate diol.

  Specifically, dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, dimer acid, terephthalic acid, isophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, their acid esters or acid anhydrides, and ethylene Glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentane glycol, 1,6-hexane glycol, 3-methyl-1,5-pentane glycol, neopentyl Glycol such as glycol, 1,8-octane glycol, 1,9-nonane glycol, diethylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, or ethylene oxide or propylene oxide adduct of bisphenol A Le or hexamethylene amine, xylylenediamine, isophoronediamine, diamines and mono- A ethanolamine or amino alcohol, either alone or polyester diols obtained by the dehydration condensation reaction of a mixture thereof, a polyester amide diols. Further examples include polyester diols such as lactone polyester diols obtained by ring-opening polymerization of cyclic ester (ie, lactone) monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerlactone. . Examples of the polyether diol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol and the like. Examples of the polyether / polyester diol include those produced from the polyether polyol and the dicarboxylic acid or acid anhydride. Examples of the polycarbonate diol include 1,4-butylene glycol, 1,5-pentane glycol, hexane glycol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, diethyl carbonate, diphenyl carbonate, and the like. Examples of the product obtained from the reaction with carbonates of Nippon Polyurethane Industry include Nipponran 980 and Nipponlane 981. Urea resin, melamine resin, epoxy resin, polyester resin, acrylic resin, polyvinyl alcohol, etc. are also generally known in the polyurethane industry and contain two or more active hydroxyl groups as long-chain polyols or parts thereof. Can be used. The molecular weight of these long chain polyols is preferably in the range of 350-8000. If the molecular weight is less than 350, the flexibility of the urethane component cannot be exhibited, and if the molecular weight exceeds 8000, the urethane group concentration of the copolymer is lowered. For example, the wear resistance and heat resistance which are one of the characteristics of polyurethane are reduced. Become scarce. These can be used alone or in combination of two or more. Among these, polycarbonate diols that are excellent in weather resistance, transparency, and mechanical strength are preferable.

  As the short-chain glycol, monomolecular diols mentioned as the raw material of the long-chain polyol. Specifically, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentane glycol, 1,6-hexane glycol, 3-methyl-1,5- Examples include pentane glycol, neopentyl glycol, 1,8-octane glycol, 1,9-nonanediol, diethylene glycol, cyclohexanone-1,4-diol, cyclohexane-1,4-dimethanol and the like. These can be used alone or in combination of two or more.

  As chain extenders, monomolecular diamines such as hydrazine, ethylenediamine and hexamethylenediamine, aromatic diamines such as toluenediamine and diaminodiphenylmethane, alicyclic diamines such as isophorone diamine, and polyether ends are amino groups. Examples thereof include polyether diamine. Examples of the amino alcohol include monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine and the like. These can be used alone or in combination of two or more.

  Here, the use ratio of the long-chain diol and the short-chain glycol is in the range of long-chain diol / short-chain glycol = 100/0 to 70/30, preferably 100/0 to 80/20, by weight.

  The molecular weight of the polymer linear polyurethane prepolymer having an ethylenically unsaturated double bond group at both ends is preferably 10,000 to 100,000. If it is less than 10,000, the distance between crosslinks of the acrylic and urethane prepolymers is short, there is a possibility of gelation during the copolymerization reaction, and sufficient tear strength cannot be obtained. On the other hand, if it exceeds 100000, the distance between crosslinks between the acrylic and urethane prepolymer becomes too large, and it becomes difficult to ensure compatibility. The molecular weight of the polymer linear polyurethane prepolymer is appropriately changed by changing the ratio of the total number of active hydrogens contained in the long-chain diol, short-chain glycol, and chain extender used and the number of moles of isocyanate groups to be reacted therewith. This can be adjusted.

  Next, in the second step of copolymerizing the vinyl compound, in addition to the vinyl compound containing at least one (meth) acrylic ester in the polymer linear urethane prepolymer produced in the first step, In addition, diazo compounds such as azobisisobutyronitrile, peroxides such as benzoyl peroxide, Kayaester-O (manufactured by Gunpaku Akzo Co., Ltd.), etc. are added as radical generators. Perform radical polymerization. At this time, the unsaturated double bonds at both ends of the polymer linear urethane prepolymer easily generate radicals, and the vinyl group compound undergoes a chain transfer reaction from this to produce an acrylic urethane copolymer. . The degree of polymerization is adjusted by adding a chain transfer agent to the reaction solution. The amount of radical generator is preferably in the range of 0.2% to 5.0% with respect to the total solid weight. The amount of the chain transfer agent is preferably 5% or less with respect to the total solid weight. If it exceeds 5%, the remaining chain transfer agent may adversely affect the weather resistance.

  Among the vinyl compounds used in the present invention, specific examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl methacrylate, iso-butyl methacrylate, and tert-butyl methacrylate. Acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, decanyl (meth) Examples include C1-C24 alkyl such as acrylate, undecanyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like. These can be used alone or in combination of two or more.

  In the present invention, a hydroxyl group-containing (meth) acrylic acid ester can also be used. Specific examples include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ε-caprolactone-modified hydroxy (meth) acrylate, and the like (meth) acrylic. A copolymer with an acid ester is preferred. In this case, an acrylic urethane copolymer having an alcoholic hydroxyl group capable of reacting with an isocyanate group is obtained. Moreover, these can be used individually or in combination of 2 or more types.

  Further, in the present invention, in addition to the compounds other than those described above, as vinyl compounds, aromatic hydrocarbon vinyl compounds such as cycloalkyl esters, styrene, α-methylstyrene and vinyl toluene, and vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. , Vinyl acetate, vinyl propionate, (meth) acrylonitrile, N-vinylpyrrolidone, or (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, and meta (acrylamide) -containing monomers. These can be used alone or in combination of two or more.

  Here, since the acrylic urethane copolymer used in the present invention has a large molecular weight of a polymer linear urethane prepolymer having saturated double bonds at both ends, the distance between crosslinks of the acrylic urethane copolymer obtained after polymerization And the molecular structure becomes a two-dimensional structure (network structure). Therefore, an acrylic urethane copolymer having good compatibility can be obtained by chemically bonding an acrylic component which is originally poorly compatible with a urethane component. Further, since the urethane prepolymer is a polymer and linear, it can exert a stretching effect when an external force is applied. Therefore, the base sheet of the acrylic urethane copolymer has the weather resistance and stain resistance which are acrylic characteristics, the flexibility and toughness which are the characteristics of urethane, and exhibits high tear strength due to the stretching effect.

  In the base sheet, the weight ratio of the polymer linear polyurethane prepolymer / vinyl compound is preferably in the range of 60/40 to 30/70. If the vinyl compound exceeds 70% by weight, the tear strength is deteriorated and it is difficult to stably cut.

  When the vinyl compound is less than 40% by weight, the tear strength is improved, but the weather resistance and stain resistance are impaired.

  The base sheet is molded by appropriately blending a crosslinking agent, a pigment, a light stabilizer, an ultraviolet absorber and the like.

  The acrylic urethane copolymer can form a dense three-dimensional structure by using a crosslinking agent. The crosslinking agent is not particularly limited as long as it is a crosslinking agent that has been conventionally used as a crosslinking agent for acrylic resins, and examples thereof include an isocyanate crosslinking agent, an epoxy crosslinking agent, and an aziridine crosslinking agent. Of these, an aliphatic isocyanate-based crosslinking agent having excellent weather resistance is preferable.

  The amount of the crosslinking agent is preferably 0.2 to 30 parts by weight with respect to 100 parts by weight of the acrylic urethane copolymer. If the amount is 0.2 parts by weight or less, the effect of addition is not recognized, and if it exceeds 30 parts by weight, the original tear strength of acrylic urethane copolymer cannot be exhibited.

  In addition, arbitrary methods may be employ | adopted for the crosslinking method, for example, a heat curing method, a radiation irradiation method, etc. are mentioned.

  By adding 0.1 to 10.0% by weight of unsaturated carboxylic acid ester to 100% by weight of the base sheet in the base sheet, the appearance is good even if the cleanliness of the film forming line is not particularly high. Film can be obtained. Although it does not specifically limit as unsaturated carboxylic acid ester, The alkanol ammonium salt of unsaturated carboxylic acid ester with a molecular weight of 1000 or less is used suitably.

  The addition ratio of the unsaturated carboxylic acid ester is preferably 0.5 to 2.0% by weight. In general, acrylic resin is easily charged with static electricity, so if the cleanliness of the production line is not high, dust in the line environment is adsorbed, and pigment aggregation occurs based on it, resulting in poor film appearance. As a countermeasure, it was common to produce in an environment with a high cleanliness of class 1000.

  However, a production line with a high degree of cleanliness has a huge equipment cost and a running cost for maintenance is a problem as a producer. Therefore, as a result of intensive studies on this point, the present inventors have solved the above problem by adding 0.1 to 10.0% by weight of an unsaturated carboxylic acid ester with respect to 100% by weight of the base sheet. Not only that, it has been found to further improve the tearability. If the added amount is less than 0.1% by weight, the intended performance is not exhibited. Therefore, when a film is formed on a production line with a low degree of cleanliness, dust in the environment or the like may be picked up and appearance defects may occur. If it exceeds 10.0% by weight, the performance beyond the addition is not manifested, resulting in an economical problem, and appearance defects such as color unevenness to the pigment system may occur.

  The thickness of the base sheet is preferably 20 to 120 μm. If the thickness is less than 20 μm, the film becomes too thin, and the workability during construction deteriorates, it becomes easy to pick up irregularities on the ground, and the weather resistance deteriorates. When the thickness exceeds 120 μm, the stiffness of the film comes out and the curved surface workability is deteriorated.

  As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer in the present invention, for example, an adhesive main component blended with an optional component such as a crosslinking agent as required is used. Examples of the main component for adhesion include acrylic, rubber, urethane, and silicone. Of these, acrylic materials are preferred in view of physical properties and economy.

  The (meth) acrylic acid ester monomer used as the main component of the acrylic pressure-sensitive adhesive layer of the present invention is a (meth) acrylic acid ester of an alcohol having an alkyl group having 1 to 12 carbon atoms, preferably 4 to 12 carbon atoms. (Meth) acrylic acid ester having an alkyl group is used, and specifically, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate , Isononyl (meth) acrylate, lauryl (meth) acrylate, and the like. These can be used alone or in combination. Due to the balance between adhesiveness and cohesiveness, etc., the main component is a (meth) acrylate ester whose homopolymer has a glass transition temperature (Tg) of −50 ° C. or less, and is composed of methyl (meth) acrylate and ethyl (meth) acrylate. (Meth) acrylic acid esters of lower alcohols such as can be used in combination.

  In addition to these vinyl monomers, monomers copolymerizable with these may be copolymerized. Monomers include carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, or anhydrides thereof, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl acrylate, polyoxyethylene (meta ), Hydroxyl-containing monomers such as polyoxypropylene (meth) acrylate, caprolactone modified (meth) acrylate, and the like. The said (meth) acrylic acid ester may be used independently and 2 or more types may be used together.

  The pressure-sensitive adhesive of the present invention may be a solvent-type acrylic pressure-sensitive adhesive polymerized in a solvent or an emulsion pressure-sensitive adhesive polymerized in water. Moreover, the block polymerization type adhesive which irradiated the ultraviolet-ray to the monomer mixture may be sufficient.

  As for the thickness of an adhesive layer, 10-50 micrometers is preferable. More preferably, it is 25-35 micrometers. When the thickness is 10 μm or less, sufficient adhesive strength cannot be obtained. On the other hand, if it exceeds 50 μm, the computer cut property is adversely affected, and the physical properties of the adhesive result in excessive quality, which is not necessary in terms of cost.

  The pressure-sensitive adhesive sheet of the present invention is characterized in that a tear load by a trouser tear method (specified in JIS K7128) is 170 mN or more. When the tear load is less than 170 mN, sufficient strength cannot be obtained, and it becomes difficult to obtain computer cutability and stable workability to a curved surface.

  The pressure-sensitive adhesive sheet of the present invention is also characterized by a 2% tensile stress of 4 to 20 N / 15 mm. If the stress at 2% tension is lower than 4 N / 15 mm, the sheet is too soft, so that it is very difficult to apply to the flat portion, and it cannot be put to practical use. On the other hand, if it is larger than 20 N / 15 mm, it is difficult to obtain a stable workability on a curved surface because the sheet is too hard.

  As described above, the pressure-sensitive adhesive sheet of the present invention is a vinyl-based polymer containing at least one (meth) acrylate ester in a polymer linear polyurethane prepolymer having ethylenically unsaturated double bond groups at both ends. Since the pressure-sensitive adhesive sheet is formed by laminating a pressure-sensitive adhesive layer on a base material sheet made of an acrylic urethane copolymer obtained by reacting a compound, it is possible to provide a sheet that is environmentally friendly and excellent in tear strength. Therefore, it has excellent workability. Further, by adding a suitable electrostatic auxiliary agent, a base sheet having a good appearance can be obtained on a production line with a low cleanness, and the tear strength is further improved.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to a following example. “Parts” means “parts by weight”. The detailed formulation and properties are summarized in Table 1.

<Example 1: Synthesis of acrylic urethane copolymer and preparation of pressure-sensitive adhesive sheet>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube has a molecular weight of 1000 polycarbonate diol (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 320.3 parts, isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 75.1 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 4.6 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 34,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction pipe, and a dropping device, 393.8 parts of a polymer linear urethane prepolymer solution, 184.4 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 331 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 84000. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. .

  On the other hand, 1 part of an isocyanate curing agent (trade name: L-55 manufactured by Nippon Polyurethane Co., Ltd.) is added to 100 parts of an acrylic adhesive (trade name: NM-1 manufactured by Sekisui Chemical Co., Ltd.), and a release paper (trade name) : SSM Lintec Co., Ltd.) and dried to a dry thickness of 30 μm. This pressure-sensitive adhesive was laminated on the substrate sheet obtained earlier to obtain a pressure-sensitive adhesive sheet.

<Example 2>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas introduction tube has a molecular weight of 1000 diol polycarbonate diol (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 324.7 parts, norbornane diisocyanate (Mitsui Takeda Chemical Co., Ltd.) ) Product name: Cosmonate NBDI) 70.6 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 4.7 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4700 mPa · s (25 ° C.), and a weight average molecular weight of 36000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction pipe, and a dropping device, 393.8 parts of a polymer linear urethane prepolymer solution, 184.4 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 331 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 4500 mPa · s (25 ° C.), and a weight average molecular weight of 86000. Furthermore, the hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and the ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of the acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. . Then, after laminating the same pressure-sensitive adhesive as in Example 1, a pressure-sensitive adhesive sheet was obtained.

<Example 3>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas introduction tube has a molecular weight of 1000 diol polycarbonate diol (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 328.1 parts, hydrogenated xylene diisocyanate (Mitsui Takeda) Chemical Co., Ltd. product name: Takenate 600) 67.2 parts and 500 parts of toluene were charged and reacted at 80 ° C. for 6 hours or more in a nitrogen atmosphere. When the isocyanate (NCO) concentration reached the theoretical amount, 4.7 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 5300 mPa · s (25 ° C.), and a weight average molecular weight of 35,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction pipe, and a dropping device, 393.8 parts of a polymer linear urethane prepolymer solution, 184.4 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 331 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 5100 mPa · s (25 ° C.), and a weight average molecular weight of 87,000. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. .

<Example 4>
In the stage which shape | molds a base material sheet, except adding 3.5 parts of unsaturated carboxylic acid ester (BIC Chemie Co., Ltd. brand name BYK-80E) with respect to 1000 parts of acrylic urethane copolymer resin solutions. A base sheet was obtained in the same manner as Example 3.

<Example 5>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube has a molecular weight of 1000 polycarbonate diol (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 320.3 parts, isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 75.1 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 4.6 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 34,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction tube, and a dropping device, 525.0 parts of a polymer linear urethane prepolymer solution, 131.9 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 252.3 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 6800 mPa · s (25 ° C.), and a weight average molecular weight of 102,000. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. .

  Then, after laminating the same pressure-sensitive adhesive as in Example 1, a pressure-sensitive adhesive sheet was obtained.

<Example 6>
In the stage which shape | molds a base material sheet, except adding 7.0 parts of unsaturated carboxylic acid ester (BIC Chemie Co., Ltd. brand name BYK-80E) with respect to 1000 parts of acrylic urethane copolymer resin solutions. A substrate sheet was obtained in the same manner as Example 5.

<Example 7>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube has a molecular weight of 1000 polycarbonate diol (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 320.3 parts, isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 75.1 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 4.6 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 34,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction tube, and a dropping device, 262.5 parts of a polymer linear urethane prepolymer solution, 236.9 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 409.8 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 2600 mPa · s (25 ° C.), and a weight average molecular weight of 67,000. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. . Then, after laminating the same pressure-sensitive adhesive as in Example 1, a pressure-sensitive adhesive sheet was obtained.

Comparative example

<Comparative Example 1: Synthesis of acrylic resin and creation of adhesive sheet>
To a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction tube, and a dropping device, 450 parts of toluene was charged and heated to 110 ° C. while stirring. There, 220.5 parts of methyl methacrylate, 77.0 parts of n-butyl methacrylate, 52.5 parts of 2-hydroxyethyl methacrylate, radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Industry Co., Ltd.) A mixture of 1.0 part and 100 parts of toluene was added dropwise over 4 hours. After completion of the dropwise addition, the reaction was carried out at the same temperature for 1 hour. Furthermore, the liquid mixture which consists of 100 parts of toluene and 0.5 part of ABN-E was dripped over 1 hour. After completion of the dropwise addition, the mixture was reacted at the same temperature for 3 hours to obtain an acrylic resin having a resin solid content of 35%, a viscosity of 110 mPa · s (25 ° C.) and a weight average molecular weight of 43,000. 1000 parts of this acrylic resin was mixed with 225 parts of Coronate HLS (manufactured by Nippon Polyurethane Industry Co., Ltd.) as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. Then, after laminating the same pressure-sensitive adhesive as in Example 1, a pressure-sensitive adhesive sheet was obtained.

<Comparative Example 2: Synthesis of acrylic / urethane blend resin and creation of adhesive sheet>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube has a molecular weight of 1000 diol polycarbonate diol (trade name: Nipponporan 981, manufactured by Nippon Polyurethane Industry Co., Ltd.) 330.4 parts, isophorone diisocyanate (Sumitomo Bayer Urethane ( Product name: Dismodule I) 69.6 parts and 600 parts of toluene were charged and reacted at 80 ° C. for 6 hours or more in a nitrogen atmosphere until NCO disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 34,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction pipe, and a dropping device, 393.8 parts of a polymer linear urethane prepolymer solution, 184.4 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 331 parts of toluene was added dropwise over 4 hours. After completion of the dropwise addition, the mixture was reacted at the same temperature for 6 hours to obtain an acrylic / urethane blend resin solution having a resin solid content concentration of 35%, a viscosity of 2500 mPa · s (25 ° C.), and a weight average molecular weight of 42,000. Further, 15 parts of Duranate D-101 (manufactured by Asahi Kasei Kogyo Co., Ltd.) as an isocyanate curing agent was mixed with 1000 parts of an acrylic / urethane blend resin solution, and this resin liquid was molded to obtain a base sheet having a thickness of 50 μm. Then, after laminating the same pressure-sensitive adhesive as in Example 1, a pressure-sensitive adhesive sheet was obtained.

<Comparative Example 3>
Other than adding 3.5 parts of electrostatic assistant (Kyoeisha Chemical Co., Ltd. trade name Floren AE-2) to 1000 parts of acrylic urethane copolymer resin solution at the stage of molding the base sheet. Obtained a base sheet in the same manner as in Comparative Example 2.

<Comparative example 4>
In a reaction vessel equipped with a stirrer, thermometer, cooler, and nitrogen gas inlet tube, polycarbonate diol having a molecular weight of 1000 (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 289.3 parts, isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 85.6 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 25.1 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 1800 mPa · s (25 ° C.), and a weight average molecular weight of 7800 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction pipe, and a dropping device, 393.8 parts of a polymer linear urethane prepolymer solution, 184.4 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution composed of 3.50 of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 331 parts of toluene was added dropwise over 4 hours. After completion of the dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 1600 mPa · s (25 ° C.), and a weight average molecular weight of 15300. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. . Then, after laminating the same pressure-sensitive adhesive as in Example 1, a pressure-sensitive adhesive sheet was obtained.

<Comparative Example 5>
In a reaction vessel equipped with a stirrer, thermometer, cooler, and nitrogen gas introduction tube, a polycarbonate diol having a molecular weight of 1000 (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 324.6 parts, isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 73.6 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 1.8 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 34500 mPa · s (25 ° C.), and a weight average molecular weight of 121,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction pipe, and a dropping device, 393.8 parts of a polymer linear urethane prepolymer solution, 184.4 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution composed of 3.50 of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 331 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 26000 mPa · s (25 ° C.), and a weight average molecular weight of 142,000. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts and 5 parts of each were added, and 15 parts of Duranate D-101 (manufactured by Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent to try to mold this resin solution. However, since the molecular weight of the polymer linear urethane prepolymer is large, the distance between crosslinks between the acrylic part and the urethane part is widened, and compatibility between the acrylic part and the urethane part cannot be ensured, so that a film cannot be formed.

<Comparative Example 6>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube has a molecular weight of 1000 polycarbonate diol (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 320.3 parts, isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 75.1 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 4.6 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 34,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler and a nitrogen gas introduction pipe, and a dropping device, 173.3 parts of a polymer linear urethane prepolymer solution, 269.2 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 466.7 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 2100 mPa · s (25 ° C.), and a weight average molecular weight of 58,000. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. .

  On the other hand, 1 part of an isocyanate curing agent (trade name: L-55 manufactured by Nippon Polyurethane Co., Ltd.) is added to 100 parts of an acrylic adhesive (trade name: NM-1 manufactured by Sekisui Chemical Co., Ltd.), and a release paper (trade name) : SSM Lintec Co., Ltd.) and dried to a dry thickness of 30 μm. This pressure-sensitive adhesive was laminated on the substrate sheet obtained earlier to obtain a pressure-sensitive adhesive sheet.

<Comparative Example 7>
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube has a molecular weight of 1000 polycarbonate diol (trade name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.) 320.3 parts, isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 75.1 parts and 500 parts of toluene were charged and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reached the theoretical amount, 4.6 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene were added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappeared. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 34,000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas inlet tube, and a dropping device, 693.2 parts of a polymer linear urethane prepolymer solution, 61.2 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. while stirring. A mixed solution composed of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Industry Co., Ltd.) and 154.8 parts of toluene was added dropwise over 4 hours. After completion of dropping, the reaction was carried out at the same temperature for 6 hours to obtain an acrylic urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 7500 mPa · s (25 ° C.), and a weight average molecular weight of 115000. Further, a hindered amine light stabilizer (HALS) “trade name: Tinuvin 622LD manufactured by Ciba Specialty Chemicals Co., Ltd.” and an ultraviolet absorber (UVA) “trade name: UV 5411 manufactured by Sun Chemical Co., Ltd.” were added to 1000 parts of an acrylic urethane copolymer resin solution. 10 parts each and 5 parts were added, 15 parts Duranate D-101 (Asahi Kasei Kogyo Co., Ltd.) was mixed as an isocyanate curing agent, and this resin solution was molded to obtain a base sheet having a thickness of 50 μm. .

On the other hand, 1 part of an isocyanate curing agent (trade name: L-55 manufactured by Nippon Polyurethane Co., Ltd.) is added to 100 parts of an acrylic adhesive (trade name: NM-1 manufactured by Sekisui Chemical Co., Ltd.), and a release paper (trade name) : SSM Lintec Co., Ltd.) and dried to a dry thickness of 30 μm. This pressure-sensitive adhesive was laminated on the substrate sheet obtained earlier to obtain a pressure-sensitive adhesive sheet.
[Evaluation]

The following evaluation was performed about the obtained adhesive sheet.
(Tear load): The tear load was measured by the trouser tear method (JIS K7128).
(Modulus): A strip sample having a width of 15 mm was mounted on a tensilon tensile tester having a chuck distance of 100 mm, a test was performed at a pulling speed of 50 mm / min, and the stress when the film was stretched by 2% was measured.
(△ E): Colorimetry (trade name: 3600CD, manufactured by Minolta Co., Ltd.) for the degree of fading after 2000 hours of accelerated exposure of the pressure-sensitive adhesive sheet prepared in accordance with the weather resistance evaluation of plastics resin (JIS A1415) Measured.
(Extracted character workability): After cutting 6 characters of "Sekisui Chemical Co., Ltd." with a cutting machine for marking film at 35mm x 35mm, the extracted character work was carried out. It was evaluated with.
○: Good △: Slightly difficult ×: Difficult (planar workability): Adhesive sheet was attached to a flat plate using a special jig (squeegee)
○: Can be pasted without problems
×: Difficult to stick because the film substrate is too soft (curved surface workability): Adhesive sheet was stuck to the corrugated plate of FIG. 1 using a special jig (squeegee)
○: Can be pasted without problems
×: Hard to stick because the film base is too hard (appearance): Confirmed the degree of dust adhesion to the base sheet
○: No dust attached
Δ: Some dust is observed
X: Dust adhesion is greatly observed. Table 1 shows the above evaluation results.

  As can be seen from Table 1, the pressure-sensitive adhesive sheet of the present invention has the same appearance and tear strength as the conventional marking film made of vinyl chloride resin, and it has been found that the lettering workability and the curved surface workability are excellent. . Further, it has been found that a good appearance can be obtained without molding on a production line having a high cleanliness. Furthermore, unlike conventional vinyl chloride resin marking films, it was also found that the environmental impact is very low because no harmful gas is generated even when incineration disposal is carried out.

  According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet that is environmentally friendly and excellent in tear strength in a general production line.

Front sectional drawing which shows the corrugate board used when evaluating the curved surface construction property of the adhesive sheet of an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Corrugated board 1a, 1b ... Convex part

Claims (3)

  A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a base material sheet, wherein the base material sheet is at least one kind of a polymer linear polyurethane prepolymer having an ethylenically unsaturated double bond group at both ends. And a vinyl urethane compound containing a (meth) acrylic acid ester is reacted with an acrylic urethane copolymer, wherein the polymer linear polyurethane prepolymer has a weight average molecular weight of 10,000 to 100,000. A pressure-sensitive adhesive sheet, wherein the weight ratio of the polymer linear polyurethane prepolymer and the vinyl compound is 60/40 to 30/70.   An unsaturated carboxylic acid ester is added at a ratio of 0.1 to 10.0% by weight with respect to 100% by weight of the base sheet, and the tear load by the trouser tear method defined in JIS K7128 is 170 mN or more. The pressure-sensitive adhesive sheet according to claim 1, wherein the 2% tensile stress of the film is 4 to 20 N / 15 mm. The decorative adhesive sheet which consists of an adhesive sheet of any one of Claims 1-2.

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