JP2020063415A - Adhesive tape - Google Patents

Abstract

To provide an adhesive tape excellent in adhesion between a polyester-based adhesive layer and an urethane-based resin foam base material or an acrylic resin foam base material.SOLUTION: An adhesive tape has an adhesive layer composed of a polyester-based adhesive on at least one surface of a base material [I], in which the base material [I] is an urethane-based resin foam base material or an acrylic resin foam base material, and the polyester-based adhesive is an adhesive formed of a polyester-based adhesive composition [II] containing a polyester-based resin (A) that has a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from polyol, and has a content of an aromatic structure-containing compound in the polyvalent carboxylic acid of 80 mol% or less and a weight average molecular weight of 5,000 to 300,000.SELECTED DRAWING: None

Description

  The present invention relates to a pressure-sensitive adhesive tape, and more particularly to a pressure-sensitive adhesive tape having excellent adhesion between a substrate and a pressure-sensitive adhesive layer made of a polyester-based pressure-sensitive adhesive.

  Conventionally, polyester resins are excellent in heat resistance, chemical resistance, durability, and mechanical strength, so they are used in a wide range of applications such as films, PET bottles, fibers, toners, electrical parts, and adhesives and adhesives. It has been used, and its use as an adhesive has been particularly noticed.

  Further, in the adhesive tape, it is effective to use a foam (foam) substrate such as a urethane resin foam substrate or an acrylic resin foam substrate as a substrate from the viewpoint of impact resistance and sealing property ( See, for example, Patent Document 1).

JP, 2017-014333, A

  However, the pressure-sensitive adhesive tape described in Patent Document 1 has insufficient adhesion between the polyester-based pressure-sensitive adhesive and the urethane-based resin foam base material or the acrylic-based resin foam base material, and the polyolefin is used as an adherend. In that case, since the adhesiveness to the adherend is insufficient, it is necessary to add a tackifier to the polyester-based pressure-sensitive adhesive, and further improvement is required.

  Under the circumstances, the present invention provides an adhesive that has excellent adhesion between the polyester-based pressure-sensitive adhesive layer and the urethane-based resin foam base material or the acrylic-based resin foam base material, and also has excellent adhesiveness to the polyolefin adherend. Intended to provide tape.

However, the present inventors have conducted intensive studies in view of such circumstances, have a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, the aromatic structure-containing compound in the polyvalent carboxylic acids By selecting a polyester-based pressure-sensitive adhesive containing a polyester resin having a content of 80 mol% or less and a weight average molecular weight of 5,000 to 300,000, a urethane-based resin foam substrate and an acrylic resin foam group The present invention has been completed by finding that the pressure-sensitive adhesive tape has excellent adhesiveness to a material and also excellent adhesiveness to a polyolefin adherend.
As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive is generally used, and an acrylic pressure-sensitive adhesive is also applied to a pressure-sensitive adhesive tape using a foam base material. Adhesion to the adherend, particularly to the adherend of polyolefin, was not satisfactory. However, it has been found that the use of a polyester-based pressure-sensitive adhesive has excellent adhesiveness to a foam base material and adhesiveness to an adherend.

  That is, the present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of a polyester-based pressure-sensitive adhesive on at least one surface of a substrate [I], wherein the substrate [I] is a urethane resin foam substrate or an acrylic resin foam. It is a base material, the polyester-based pressure-sensitive adhesive has a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, and the content of the aromatic structure-containing compound in the polyvalent carboxylic acid is 80 mol% or less. And the summary is a pressure-sensitive adhesive tape which is a pressure-sensitive adhesive formed from a polyester-based pressure-sensitive adhesive composition [II] containing a polyester-based resin (A) having a weight average molecular weight of 5,000 to 300,000. It is a thing.

  The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of a polyester-based pressure-sensitive adhesive on at least one surface of a substrate [I], wherein the substrate [I] is a urethane resin foam substrate or an acrylic resin. It is a foam base material, and the polyester-based pressure-sensitive adhesive has a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, and the content of the aromatic structure-containing compound in the polyvalent carboxylic acid is 80 mol%. The following is a pressure-sensitive adhesive formed from a polyester-based pressure-sensitive adhesive composition [II] containing a polyester-based resin (A) having a weight average molecular weight of 5,000 to 300,000. Therefore, the pressure-sensitive adhesive tape of the present invention has excellent adhesion between the polyester-based pressure-sensitive adhesive layer and the urethane-based resin foam base material or the acrylic-based resin foam base material, and also excellent adhesion to the polyolefin adherend.

Hereinafter, the constitution of the present invention will be described in detail, but these show one example of desirable embodiments.
In the present invention, the "tape" is meant to include "film" and "sheet".
In the present invention, "(meth) acrylic" means acrylic or methacrylic, "(meth) acryloyl" means acryloyl or methacryloyl, and "(meth) acrylate" means acrylate or methacrylate. .

<Substrate [I]>
The present invention is characterized in that a urethane resin foam substrate or an acrylic resin foam substrate is used as the substrate [I] of the pressure-sensitive adhesive sheet.
The urethane resin foam base material or the acrylic resin foam base material is a foamed product obtained by foaming the urethane resin composition or the acrylic resin composition.

The apparent density of the urethane resin foam base material or the acrylic resin foam base material is preferably 100 to 1,000 kg / m ³ , and particularly preferably 200, from the viewpoint of excellent adhesion to the pressure-sensitive adhesive layer. ˜900 kg / m ³ , more preferably 250 to 800 kg / m ³ , and most preferably 300 to 700 kg / m ³ . If the apparent density is too low or too high, the adhesion with the pressure-sensitive adhesive layer tends to decrease.
The apparent density can be measured according to JIS K7222.

  The bubbles contained in the urethane resin foam base material or the acrylic resin foam base material may be closed cells or open cells. In addition, closed cells and open cells may be mixed.

  The shape of the bubbles is usually spherical, but is not limited to this. The average diameter of the bubbles (average bubble diameter) is usually 5 to 500 μm, preferably 50 to 400 μm. When the average cell diameter is within the above range, the resin foam base material tends to have excellent tensile strength, flexibility, workability, surface smoothness, and followability.

  The thickness of the urethane resin foam base material or the acrylic resin foam base material is preferably 0.1 to 2 mm, particularly preferably 0.2 to 1 from the viewpoint of excellent adhesion to the pressure-sensitive adhesive layer. It is 0.5 mm, more preferably 0.3 to 1 mm. If the thickness of the base material is too thin, the flexibility and impact resistance tend to decrease, and if the thickness of the urethane resin foam base material or acrylic resin foam base material is too large, the processability and surface smoothness decrease. Tend to do.

  The tensile strength of the urethane resin foam base material or the acrylic resin foam base material is usually 0.1 to 2.5 MPa, preferably 0.3 to 1.5 MPa. If the tensile strength is too low, tearing tends to occur due to insufficient strength, and if the tensile strength is too high, impact resistance tends to decrease.

  The elongation of the urethane resin foam base material or the acrylic resin foam base material is usually 50 to 300%, preferably 70 to 200%. If the elongation is too small, the impact resistance tends to decrease, and if the elongation is too large, the adhesive strength tends to decrease due to insufficient strength.

  The tensile strength and elongation of the urethane resin foam base material or acrylic resin foam base material are cut so that the distance between chucks is 25 mm when the base material is cut into 10 mm × 50 mm in an environment of 23 ° C. and 50% RH. To an autograph (“Autograph AG-X PLUS 500N” manufactured by Shimadzu Corp.) and measured at a tensile speed of 50 mm / min.

As described above, the substrate [I] used in the present invention is a urethane resin foam substrate or an acrylic resin foam substrate. Of these, urethane resin foam base materials are preferable.
Hereinafter, each foam substrate will be described.

[Urethane resin foam base material]
The urethane-based resin foam base material is formed by foaming a urethane-based resin composition containing a urethane-based resin obtained by reacting a polyol and a polyisocyanate.

  The polyol may be any of polyester polyol, polyether polyol, and polymer polyol. These may be used alone or in combination of two or more.

  Examples of the polyester polyol, for example, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, Dicarboxylic acids such as sebacic acid, 1,4-cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid, maleic acid and fumaric acid. , Or one of these dicarboxylic acid anhydrides, and ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butane Diol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octane All, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1, 4-dimethanol, dimer acid diol, ethylene oxide or propylene oxide adduct of bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol and other low molecular weight polyols having a molecular weight of 500 or less. Mention may be made of those obtained from polycondensation reactions with one or more of the classes. Also, a polyester-amide polyol obtained by replacing a part of the low molecular weight polyol with a low molecular weight polyamine such as hexamethylene diamine, isophorone diamine, monoethanol amine or a low molecular weight amino alcohol can be used.

  Examples of the above-mentioned polyether polyols include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, sucrose, and the like. A polyether polyol obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to a polyhydric alcohol can be mentioned. Specifically, for example, propylene oxide or ethylene oxide is added to polyglycerin having an average number of functional groups of 2 to 5, the ethylene oxide content is 50 to 75% by weight of the whole, and the number average molecular weight is 2,000 to 7. 1,000 polyether polyols can be used. Further, the polyether polyol may be one obtained by ring-opening polymerization of a cyclic ether containing alkylene oxide.

  Examples of the polymer polyol include those obtained by graft-polymerizing a vinyl compound such as acrylonitrile, styrene, and alkyl (meth) acrylate on the above polyether polyol.

  The polyisocyanate may be aromatic, alicyclic, or aliphatic, and is a divalent isocyanate having two isocyanate groups in one molecule, or three or more in one molecule. It may be a trivalent or higher valent isocyanate having the above isocyanate group. These polyisocyanates may be used alone or in combination of two or more.

  Examples of the divalent isocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate and 2,4 ′. -Diphenylmethane dianate, 2,2'-diphenylmethane diisocyanate, xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisonate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, etc. Alicyclic diisocyanates such as aromatic diisocyanates, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexane diisocyanate, butane 1,4-diisocyanate, hexamethylene diisocyanate, can be mentioned isopropylene diisocyanate, methylene diisocyanate, the aliphatic diisocyanates such as lysine diisocyanate.

  Further, as the trivalent or higher valent isocyanate, 1-methylbenzol-2,4,6-triisocyanate, 1,3,5-trimethylbenzol-2,4,6-triisocyanate, biphenyl-2,4,4 ' -Triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2 ', 5,5' tetraisocyanate, tri Examples thereof include phenylmethane-4,4 ′, 4 ″ -triisocyanate and aromatic polyisocyanates such as polymeric MDI. Other urethane prepolymers can also be used. The polyisocyanates may be used alone or in combination of two or more. For example, one type of aliphatic isocyanate and two types of aromatic isocyanate may be used in combination.

Examples of the reaction method for reacting the above-mentioned polyol and polyisocyanate to obtain a urethane resin include a one-shot method and a prepolymer method.
The one-shot method is a method of reacting a polyol and a polyisocyanate with all other raw materials such as a catalyst, a foaming agent, a surfactant and an additive described later in one step.
On the other hand, in the prepolymer method, a polyol and a polyisocyanate are reacted in advance to obtain a prepolymer having an isocyanate group at an end, and a catalyst, a foaming agent, a surfactant, an additive, and other raw materials are added to the prepolymer. It is a method of reacting a polyol in the presence.

  The compounding ratio in the reaction between the polyol and the polyisocyanate can be represented by the isocyanate index, and is usually 95 to 120, preferably 100 to 115. When the isocyanate index is low, reactivity and crosslinking are insufficient, and foaming stability and strain tend to be reduced. When the isocyanate index is high, the crosslinking becomes remarkable, the foam shrinks after foaming, the exothermic reaction is promoted, and scorch or burn tends to occur due to the high reaction temperature. The isocyanate index means the percentage of the equivalent ratio of the isocyanate group concentration in polyisocyanate to the total active hydrogen group concentration in the polyol.

  A catalyst is preferably used for the reaction between the polyol and the polyisocyanate. Examples of the catalyst include amine catalysts and metal catalysts. These catalysts may be used alone or in combination of two or more.

  Examples of the amine-based catalyst include 1,4-diazabicyclo (2,2,2) octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N ′, N ″, N ′. '-Pentamethyldiethylenetriamine, N, N-dimethylcyclohexylamine, N-methyldicyclohexylamine, N, N, N', N'-tetramethylpropylenediamine, N, N, N ', N'-tetramethylhexamethylenediamine , N-ethylmorpholine, N-methylmorpholine, N, N-dimethylethanolamine, N, N-diethylethanolamine, triethylamine, triethylenediamine, diethanolamine, dimethylaminomorpholine, tetramethylguanidine and the like.

  Examples of the metal catalyst include dibutyltin dilaurate, trimethyltin hydroxide, tetra-n-butyltin, zinc octenoate, tin octenoate, tin octylate, cobalt naphthenate, dibutylbismuth dilaurate, dioctylbismuth dilaurate, 2- Ethylhexanoic acid bismuth salt, naphthenic acid bismuth salt, isodecanic acid bismuth salt, neodecanoic acid bismuth salt, lauric acid bismuth salt, maleic acid bismuth salt, stearic acid bismuth salt, oleic acid bismuth salt, linoleic acid bismuth salt, bismuth acetate salt, Bismuth Ribis neodecanoate, bismuth disalicylate, bismuth digallate, organometallic compounds such as organozirconium, stannous chloride, stannic chloride, bismuth nitrate, bismuth bromide, bismuth iodide, bismuth sulfide, Inorganic Zirconi Arm, inorganic metal compounds such as zirconium alone are exemplified. Moreover, what used together two or more types of catalysts, such as zinc 2-ethylhexanoate / zirconium tetraacetylacetonate, is mentioned.

  Further, the urethane resin composition preferably contains a foaming agent. The foaming agent may be one that is normally used for urethane-based resin foam substrates, and examples thereof include water, pentane, cyclopentane, methylene chloride, carbon dioxide gas and the like. These foaming agents can be used alone or in combination of two or more.

Further, the urethane resin composition preferably contains a surfactant. The surfactant may be any one that is generally adopted for urethane resin foam substrates, and examples thereof include silicone compounds and nonionic surfactants.
The blending amount of the surfactant is usually 0.5 to 2 parts by weight with respect to 100 parts by weight of the polyol.

  Further, various additives may be added to the urethane resin composition as long as the effects of the present invention are not impaired. Examples of the additive include a curing accelerator, an antioxidant, an ultraviolet absorber, a light resistance stabilizer, a silane coupling agent, a tackifier, a wax, a plasticizer, a stabilizer, a filler, a thixotropic agent, and a pigment. , Fluorescent whitening agents, colorants, antioxidants, diluents and the like. Moreover, you may mix | blend thermoplastic resins other than urethane type resin.

  For example, slab molding or molding is used for producing a urethane resin foam substrate using the urethane resin composition, and any of these may be used.

  Then, by adjusting the above-mentioned raw materials so that the physical properties of the urethane resin foam base material are within the ranges described above, the urethane resin foam base material that can be used in the present invention is obtained.

[Acrylic resin foam base material]
The acrylic resin foam base material is a (meth) acrylic acid alkyl ester-based monomer, and if necessary, a functional group-containing monomer, a polyfunctional monomer (a compound having two or more ethylenically unsaturated groups), and other co-functional monomers. It is obtained by foaming an acrylic resin composition containing an acrylic resin obtained by polymerizing a polymerization component containing a polymerizable monomer.

  The (meth) acrylic acid alkyl ester-based monomer is a main component of the acrylic resin, and the number of carbon atoms of the alkyl group is usually 1 to 20, preferably 1 to 14, and particularly preferably 1 to 10. Is.

Specific examples of the (meth) acrylic acid alkyl ester-based monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth). Acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acryl , Undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, Aliphatic (meth) acrylic acid alkyl esters such as nonadecyl (meth) acrylate and eicosyl (meth) acrylate; alicyclic (meth) acrylic acid alkyl esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate Can be mentioned. These may be used alone or in combination of two or more.
Among the above-mentioned (meth) acrylic acid alkyl ester-based monomers, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable from the viewpoints of copolymerizability, easy handling, and easy availability of raw materials.

  The content of the (meth) acrylic acid alkyl ester-based monomer in the polymerization component is usually 60 to 99.5% by weight, preferably 70 to 99% by weight, and particularly preferably 80 to 95% by weight. .

  Examples of the functional group-containing monomer include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, an amide group-containing monomer, a glycidyl group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, and an oxazoline group-containing monomer. , Acetoacetyl group-containing monomer, isocyanate group-containing monomer, alkoxy group-containing monomer, alkoxysilyl group-containing monomer and the like. These functional group-containing monomers can be used alone or in combination of two or more kinds.

  Specific examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and the like. 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl ( (Meth) acrylate, hydroxyalkyl (meth) acrylates such as (4-hydroxymethylcyclohexyl) methyl (meth) acrylate, and caprolactone-modified 2-hydroxyethyl (meth) acrylate. Rolactone-modified monomers, oxyalkylene-modified monomers such as diethylene glycol (meth) acrylate and polyethylene glycol (meth) acrylate, primary hydroxyl group-containing monomers such as 2-acryloyloxyethyl-2-hydroxyethylphthalic acid; 2-hydroxypropyl (meth ) Secondary hydroxyl group-containing monomers such as acrylate, 2-hydroxybutyl (meth) acrylate and 3-chloro-2-hydroxypropyl (meth) acrylate; tertiary hydroxyl groups such as 2,2-dimethyl2-hydroxyethyl (meth) acrylate Examples thereof include contained monomers.

  Examples of the carboxy group-containing monomer include (meth) acrylic acid, (meth) acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide N-glycolic acid. , Cinnamic acid and the like.

  Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like.

  Examples of the amide group-containing monomer include ethoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide, (meth) acryloylmorpholine, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, dimethylaminopropylacrylamide, ( (Meth) acrylamide (meth) acrylamide-based monomers such as N-methylol (meth) acrylamide.

  Examples of the glycidyl group-containing monomer include glycidyl methacrylate and allyl glycidyl methacrylate.

  Examples of the sulfonic acid group-containing monomer include olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid, 2-acrylamido-2-methylolpropane sulfonic acid, styrene sulfonic acid and salts thereof. .

  Examples of the phosphoric acid group-containing monomer include 2-hydroxyethylacryloyl phosphate.

  Examples of the oxazoline group-containing monomer include 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline and the like.

  Examples of the acetoacetyl group-containing monomer include 2- (acetoacetoxy) ethyl (meth) acrylate and allyl acetoacetate.

  Examples of the isocyanate group-containing monomer include 2- (meth) acryloyloxyethyl isocyanate.

  Examples of the alkoxy group-containing monomer include methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and ethoxypropyl (meth) acrylate.

  Examples of the alkoxysilyl group-containing monomer include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, and 3- (meth ) Acryloxypropylmethyldiethoxysilane and the like can be mentioned.

  The content of the functional group-containing monomer in the polymerization component is usually 0.5% by weight or more, preferably 1 to 30% by weight, more preferably 3 to 25% by weight, particularly preferably It is 5 to 20% by weight.

  Examples of the polyfunctional monomer include 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polyethylene glycol di (meth). ) Acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, penta Erythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. It is below. These may be used alone or in combination of two or more.

  The content of the polyfunctional monomer in the polymerization component is usually 2% by weight or less, preferably 1% by weight or less.

  Examples of the other copolymerizable monomer include vinyl acetate, vinyl propionate, vinyl stearate, vinyl benzoate and other carboxylic acid vinyl ester monomers; phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth). ) Acrylate, phenyldiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, styrene, monomers containing an aromatic ring such as α-methylstyrene; Biphenyloxy structure such as biphenyloxyethyl (meth) acrylate Containing (meth) acrylic acid ester type monomer; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, ethoxydie Monomers containing alkoxy groups or oxyalkylene groups such as len glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, polypropylene glycol mono (meth) acrylate; acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, alkyl vinyl ether, Examples thereof include vinyltoluene, vinylpyridine, vinylpyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acrylic chloride, methyl vinyl ketone, allyl trimethyl ammonium chloride, and dimethyl allyl vinyl ketone. These may be used alone or in combination of two or more.

  When the other copolymerizable monomer is used, its content in the polymerization component is usually 40% by weight or less, preferably 30% by weight or less, more preferably 25% by weight or less.

  The acrylic resin is obtained by appropriately selecting and polymerizing the (meth) acrylic acid alkyl ester-based monomer and, if necessary, a functional group-containing monomer, a polyfunctional monomer, and another copolymerizable monomer. . As such a polymerization method, a conventionally known method such as solution radical polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, photopolymerization and radiation polymerization can be appropriately used.

  In the polymerization of the acrylic resin, it is preferable to use a known general polymerization initiator depending on the polymerization method, the polymerization mode and the like. The polymerization initiators may be used alone or in combination of two or more.

  The glass transition temperature (Tg) of the acrylic resin obtained by the above-mentioned polymerization method is usually −70 to −10 ° C., preferably −70 to −20 ° C., particularly preferably −70 to −30 ° C., and further preferably Is -70 to -40 ° C, particularly preferably -65 to -50 ° C.

  The glass transition temperature (Tg) of the acrylic resin is a value measured using a differential scanning calorimeter “DSC Q2000” manufactured by TA Instruments. The measurement temperature range is −80 to 40 ° C., and the temperature rising rate is 5 ° C./min.

  The acrylic resin composition may contain a crosslinking agent. As the cross-linking agent, it is possible to use a general cross-linking agent known in the field of acrylic pressure-sensitive adhesives, for example, epoxy-based cross-linking agent, isocyanate-based cross-linking agent, silicone-based cross-linking agent, oxazoline-based cross-linking agent, aziridine-based cross-linking agent. Agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents and the like. These cross-linking agents may be used alone or in combination of two or more.

  Further, the acrylic resin composition may contain a filler. By including a filler, the shear strength of the acrylic resin foam base material can be increased, and as a result, the peel strength for peeling the adhesive tape from the adherend tends to be improved. Further, there is a tendency that excessive deformation of the pressure-sensitive adhesive tape is suppressed and the balance between flexibility and cohesiveness of the pressure-sensitive adhesive tape as a whole is easily adjusted.

  As the filler, various particulate substances can be used, and as the constituent material of the particulate substances, for example, metals such as copper, nickel, aluminum, chromium, iron, stainless steel, metals such as alumina, zirconia, etc. Oxides, carbides such as silicon carbide, boron carbide and nitrogen carbide, nitrides such as aluminum nitride, silicon nitride and boron nitride, inorganic materials such as calcium carbide, calcium carbonate, aluminum hydroxide, glass and silica, polystyrene, acrylics Resin (for example, polymethylmethacrylate etc.), phenol resin, benzoguanamine resin, urea resin, silicone resin, polyester, polyurethane, polyethylene, polypropylene, polyamide (for example, nylon etc.), polyimide, polymer such as polyvinylidene chloride, volcanic shirasu, Natural raw material grains such as sand Etc. The. These may be used alone or in combination of two or more.

The outer shape and the particle shape of the above particulate matter include, for example, a spherical shape, a flake shape, and an irregular shape. The particle structure of the particulate matter is not particularly limited, and examples thereof include a dense structure, a porous structure, a hollow structure, and the like.
Among them, it is preferable that the above-mentioned filler contains a hollow-structured particulate substance (hereinafter also referred to as “hollow particle”), and it is more preferable that the filler contains hollow particles made of an inorganic material. Examples of such hollow particles include glass balloons such as hollow glass balloons; hollow balloons made of a metal compound such as hollow alumina balloons; porcelain hollow balloons such as hollow ceramic balloons.

  As the hollow glass balloon, for example, trade names “Glass Micro Balloon”, “Fuji Balloon H-40”, “Fuji Balloon H-35” manufactured by Fuji Silysia Chemical Ltd., and “CELSTAR Z-20” manufactured by Tokai Kogyo Co., Ltd. , "Cellstar Z-27", "Cellstar CZ-31T", "Cellstar Z-36", "Cellstar Z-39", "Cellstar T-36", "Cellstar PZ-6000", products of Fine Balloon Company Name "Silux Fine Balloon", trade names "Q-CEL (trademark) 5020", "Q-CEL (trademark) 7014", trade names "Sphererice (trademark) 110P8", "Sphererice" manufactured by Potters Barottini Co., Ltd. (Trademark) 25P45 "," Spherelic (trademark) 34P30 "," Spherelic (trademark) Commercially available products such as standard) 60P18 ”, trade names“ Super Balloon BA-15 ”and“ Super Balloon 732C ”manufactured by Showa Chemical Industry Co., Ltd. can be used.

The average particle size of the hollow particles used is not particularly limited. For example, it is usually 1 to 500 μm, preferably 5 to 400 μm, more preferably 10 to 300 μm, further preferably 10 to 200 μm, and particularly preferably 10 to 150 μm.
The average particle size of the hollow particles is usually 50% or less, preferably 30% or less, and more preferably 10% or less of the thickness of the foam sheet.

The specific gravity of the hollow particles is not particularly limited, but in consideration of uniform dispersibility and mechanical strength, for example, usually 0.1 to 1.8 g / cm ³ , preferably 0.1 to 1.5 g / cm ³ , more preferably 0.1 to 0.5 g / cm ^3, particularly preferably 0.2-0.5 g / cm ^3.
The amount of the hollow particles to be used is not particularly limited, and can be, for example, 1 to 70% by volume, preferably 5 to 50% by volume, and particularly preferably 10 to 10% by volume of the entire volume of the foam sheet. It is preferably set to -40% by volume.

  The average particle diameter of the filler is, for example, usually 1 to 500 μm, preferably 5 to 400 μm, more preferably 10 to 300 μm, and particularly preferably 10 to 150 μm. The average particle size of the filler is usually 50% or less, preferably 30% or less, and particularly preferably 10% or less of the thickness of the acrylic resin foam substrate.

  The blending amount of the above-mentioned filler is, for example, usually 1 to 70% by volume, preferably 5 to 50% by volume, and particularly preferably 10 to 40% by volume of the entire acrylic resin foam substrate. Further, from the viewpoint of improving the peeling force, the amount of the filler compounded is 15% by volume or more, preferably 20% by volume or more, and more preferably 30% by volume or more based on the entire acrylic resin foam substrate.

  The acrylic resin composition, to the extent that the effects of the present invention are not impaired, for example, tackifiers such as acrylic oligomers, thermoplastic resins other than acrylic resins, plasticizers, softeners, colorants (for example, (Pigments, dyes, etc.), antioxidants, leveling agents, stabilizers, preservatives and other additives may be added. These additives may be used alone or in combination of two or more.

  As described above, the acrylic resin foam base material is obtained by foaming the acrylic resin composition, and a known method can be adopted as a method for foaming.

  Examples of the method for foam-forming the acrylic resin composition include, for example, a method of curing an acrylic resin composition in which a bubble-forming gas is mixed in advance, an acrylic resin composition containing a foaming agent, and Examples thereof include a method of forming bubbles.

  In the method of curing the acrylic resin composition in which the bubble forming gas is mixed in advance, a known bubble mixing method can be used as a method of preparing the acrylic resin composition in which the bubble forming gas is mixed.

  As the foaming agent in the method of forming bubbles from the foaming agent using the acrylic resin composition containing the foaming agent, a known foaming agent for an acrylic resin foam substrate can be used. As the foaming agent, heat-expandable microspheres and the like are preferable.

  Further, in the acrylic resin composition containing the above-mentioned bubble-forming gas or the acrylic resin composition containing a foaming agent, a surfactant is blended from the viewpoint of the mixing property of the bubble-forming gas and the stability of bubbles. It may have been done. Examples of the above-mentioned surfactant include ionic surfactants, hydrocarbon-based surfactants, silicone-based surfactants, fluorine-based surfactants and the like. These surfactants may be used alone or in combination of two or more. Among them, a fluorine-based surfactant is preferable, and a fluorine-based surfactant having an oxyalkylene group (for example, an oxyalkylene group having 2 to 3 carbon atoms) and a fluorinated hydrocarbon group in the molecule is particularly preferable.

  The content of the surfactant is usually 0.01 to 3 parts by weight in terms of solid content based on 100 parts by weight of the acrylic resin.

  An acrylic resin foam base material is formed by applying an acrylic resin composition containing the above bubble-forming gas or an acrylic resin composition containing a foaming agent onto a predetermined surface and curing the same. be able to.

  Examples of the curing method include a heating method and a method of irradiating with active energy rays (for example, ultraviolet rays).

  Then, the acrylic resin foam base material that can be used in the present invention is obtained by adjusting the above raw materials so that the physical properties of the acrylic resin foam base material fall within the ranges described above.

<Polyester adhesive composition [II]>
The polyester-based pressure-sensitive adhesive composition [II] used in the present invention has a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, and the content of the aromatic structure-containing compound in the polyvalent carboxylic acid, and The polyester resin (A) having a weight average molecular weight within a specific range is contained.

The polyester-based pressure-sensitive adhesive composition [II] used in the present invention contains the above polyester-based resin (A) as an essential component, a hydrolysis inhibitor (B), a urethanization catalyst (C), and a crosslinking agent (D). It is preferable to contain at least one selected from the group consisting of, and it is more preferable to contain any of the components (B) to (D).
Each component constituting such a polyester-based pressure-sensitive adhesive composition [II] will be sequentially described below.

[Polyester resin (A)]
The polyester resin (A) is usually obtained by copolymerizing a copolymerization component containing a polyvalent carboxylic acid (a1) and a polyol (a2) as constituent raw materials, and the polyester resin (A) is The resin composition has a structural unit derived from the polycarboxylic acid (a1) and a structural unit derived from the polyol (a2).
In the present invention, the term "carboxylic acid" includes not only carboxylic acid but also carboxylic acid derivatives such as carboxylic acid salt, carboxylic acid anhydride, carboxylic acid halide and carboxylic acid ester.

  Further, the polyester resin (A) used in the present invention is a compound containing a hydrogenated polybutadiene structure from the viewpoint of adhesiveness to a urethane resin foam base material or an acrylic resin foam base material, and adhesiveness to a polyolefin adherend. It is preferable to copolymerize a copolymerization component containing (a3). By copolymerizing the hydrogenated polybutadiene structure-containing compound (a3), the polyester-based resin (A) becomes a hydrogenated polybutadiene structure-containing compound (a3). To have a structural unit of origin. The hydrogenated polybutadiene structure-containing compound (a3) is preferably contained as at least one of the polyvalent carboxylic acids (a1) and the polyol (a2), which are constituent raw materials of the polyester resin (A).

[Polyvalent carboxylic acids (a1)]
Examples of the polyvalent carboxylic acids (a1) used as a constituent raw material of the polyester resin (A) include divalent carboxylic acids and trivalent or higher polyvalent carboxylic acids, which stabilize the polyester resin (A). The divalent carboxylic acids are preferably used because they can be obtained easily.

Examples of the divalent carboxylic acid, for example,
Malonic acids, dimethylmalonic acids, succinic acids, glutaric acids, adipic acids, trimethyladipic acids, pimelic acids, 2,2-dimethylglutaric acids, azelaic acids, sebacic acids, fumaric acids, maleic acids, itaconic acids, thiodipropionic acids , Diglycolic acids, 1,9-nonanedicarboxylic acids, and the like aliphatic dicarboxylic acids;
Phthalic acids, terephthalic acids, isophthalic acids, benzylmalonic acids, diphenic acids, 4,4′-oxydibenzoic acids, 1,8-naphthalenedicarboxylic acids, 2,3-naphthalenedicarboxylic acids, 2,7-naphthalenedicarboxylic acids, etc. Aromatic dicarboxylic acids such as naphthalene dicarboxylic acids;
Alicyclic rings of 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, adamantanedicarboxylic acid, etc. Group dicarboxylic acids;
Etc.
Examples of the trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, adamantane tricarboxylic acid, trimesic acid, and the like.
These polyvalent carboxylic acids (a1) can be used alone or in combination of two or more kinds.

  Further, among the above polyvalent carboxylic acids (a1), aromatic polyvalent carboxylic acids, particularly asymmetric aromatic polyvalent carboxylic acids (a1-1) from the viewpoint of reducing the crystallinity of the polyester resin (A). And asymmetric aromatic polycarboxylic acids (a1-1) include, for example, phthalic acids, isophthalic acids, 1,8-naphthalenedicarboxylic acids, 2,3-naphthalenedicarboxylic acids, 2,7 -Naphthalenedicarboxylic acids and the like are mentioned, and among them, isophthalic acids are particularly preferably used from the viewpoint of reactivity.

  The content of the aromatic polyvalent carboxylic acids, particularly the asymmetric aromatic polyvalent carboxylic acids (a1-1) is 80 mol% or less, particularly 1 to 1 with respect to the total amount of the polyvalent carboxylic acids (a1). It is preferably 80 mol%, particularly preferably 2 to 70 mol%, further preferably 3 to 60 mol%, particularly preferably 5 to 40 mol%. If the content is too small, the resin tends to crystallize and sufficient adhesive performance cannot be obtained, and if it is too large, the compatibility and the initial adhesion (tack) tend to be lowered.

  Further, among the polyvalent carboxylic acids (a1), from the viewpoint of lowering the crystallinity of the polyester resin (A) from another viewpoint, an aliphatic polycarboxylic acid (a1-2) having an odd number of carbon atoms is contained. Preferably, the aliphatic polycarboxylic acid having an odd number of carbon atoms (a1-2) includes, for example, malonic acid, glutaric acid, pimelic acid, azelaic acid, 1,9-nonanedicarboxylic acid, and the like. However, azelaic acids are particularly preferably used.

  The content of the aliphatic polycarboxylic acid (a1-2) having an odd number of carbon atoms is preferably 5 to 100 mol% based on the whole polycarboxylic acid (a1). In particular, when importance is attached to the solution transparency, it is preferably 5 to 95 mol%, particularly preferably 10 to 90 mol%, and further preferably 20 to 85 mol based on the whole polycarboxylic acid (a1). %, Particularly preferably 30 to 80 mol%. If the content is too small, the resin tends to crystallize and sufficient adhesiveness may not be obtained.

  In the present invention, it is also preferable to use asymmetric aromatic polyvalent carboxylic acids (a1-1) and aliphatic polyvalent carboxylic acids in combination as the polyvalent carboxylic acids (a1) from the viewpoint of adhesiveness. As the content ratio (molar ratio) of the asymmetric aromatic polycarboxylic acid (a1-1) and the aliphatic polycarboxylic acid, the asymmetric aromatic polycarboxylic acid (a1-1) / aliphatic polycarboxylic acid = 1/99 to 70/30 is preferable, 5/95 to 50/50 is particularly preferable, and 10/90 to 30/70 is further preferable.

  In order to increase the number of branch points in the polyester resin (A), trivalent or higher polyvalent carboxylic acids can be used, and among them, trimellitic acids are used because gelation is relatively unlikely to occur. Is preferred.

  The content of the trivalent or higher polycarboxylic acid is preferably 10 mol% or less, particularly preferably, based on the total amount of the polycarboxylic acid (a1) from the viewpoint that the cohesive force of the pressure-sensitive adhesive can be increased. It is 0.1 to 5 mol%, and if the content is too large, gelation tends to occur during the production of the polyester resin (A).

[Polyol (a2)]
Examples of the polyol (a2) used as a constituent raw material of the polyester resin (A) include a dihydric alcohol and a trihydric or higher polyol.

Examples of the dihydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, and 2 -Methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl -1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,2 Aliphatic diols such as 4-trimethyl-1,6-hexanediol;
1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, spiroglycol, tricyclodecanedimethanol, adamantanediol, 2,2,4,4-tetramethyl-1,3 An alicyclic diol such as cyclobutanediol;
4,4'-thiodiphenol, 4,4'-methylenediphenol, bisphenol, bisphenolfluorene, 4,4'-dihydroxybiphenyl, o-, m- and p-dihydroxybenzene, 2,5-naphthalenediol, p An aromatic diol such as xylene diol;
And ethylene oxide and propylene oxide adducts thereof.
Further, fatty acid esters derived from castor oil, dimer diols derived from oleic acid, erucic acid and the like, glycerol monostearate and the like can be mentioned.
Examples of the trihydric or higher polyols include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, and adamantanetriol.
These polyols (a2) can be used alone or in combination of two or more.

Among the above polyols (a2), it is preferable to contain the branched structure-containing polyol (a2-1) from the viewpoint of increasing branch points and degrading crystallinity. Examples of the branched structure-containing polyol (a2-1) include neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2,2-diethyl- 1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2- Methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3,5-trimethyl-1,3-pentanediol, 2-methyl-1,6-hexanediol and the like can be mentioned. To be Of these, neopentyl glycol is particularly preferable.
The branched structure-containing polyol (a2-1) excludes hydrogenated polybutadiene polyol (a3-2) described later.

  The content of the branched structure-containing polyol (a2-1) is preferably 5 to 99 mol%, particularly 10 to 95 mol%, and further 30 to 90 mol% with respect to the entire polyol (a2). Preferably there is. If the content is too small, the resin tends to crystallize and sufficient adhesive performance is difficult to be obtained, and if it is too large, the reaction time in the production of the polyester resin (A) tends to be long.

  On the other hand, among the above-mentioned polyols (a2), it is preferable to contain the linear polyol (a2-2) from the viewpoint of reactivity, and the linear polyol having 2 to 40 carbon atoms is more preferable. Examples of the linear polyol (a2-2) include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol. And aliphatic glycols such as 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Among them, 1,4-butanediol is particularly preferable.

  The content of the straight-chain polyol (a2-2) is preferably 1 to 100 mol%, more preferably 3 to 95 mol%, especially 5 to 90 mol%, based on the whole polyol (a2). Is preferably 10 to 80 mol%, particularly preferably 15 to 60 mol%. If the content is too small, it tends to be difficult to obtain stable resin formation.

  Further, a polyol having a valence of 3 or more can be used for the purpose of increasing branch points in the polyester resin (A). Examples of the polyol having a valence of 3 or more include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, and the like. Examples include trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, and adamantanetriol.

  The content of the trihydric or higher polyol is preferably 20 mol% or less, more preferably 0.1 to 10 mol%, particularly preferably 0.1% or less, based on the whole polyol (a2). 5 to 5 mol% is preferable. When the content of the trivalent or higher polyol is too large, it tends to be difficult to produce the polyester resin (A).

  As the compounding ratio of the polyvalent carboxylic acid (a1) and the polyol (a2), the polyol (a2) is preferably 1 to 3 equivalents, and particularly preferably 1.1 per 1 equivalent of the polyvalent carboxylic acid (a1). ~ 2 equivalents. If the blending ratio of the polyol (a2) is too low, the acid value tends to be high, making it difficult to increase the molecular weight, and if it is too high, the yield tends to decrease.

[Compound containing hydrogenated polybutadiene structure (a3)]
As described above, the polyester resin (A) used in the present invention preferably has a structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3). A hydrogenated polybutadiene structure-containing compound (a3) can be appropriately blended as a constituent raw material of such a polyester resin (A), but from the viewpoint of achieving the object of the present invention, a polyvalent carboxylic acid (a1) At least one of the polyol (a2) and the hydrogenated polybutadiene structure-containing compound (a3) is preferably contained.
Hereinafter, the hydrogenated polybutadiene structure-containing compound (a3) contained in the polycarboxylic acid (a1) is referred to as a hydrogenated polybutadiene structure-containing polycarboxylic acid (a3-1), and the hydrogenated polybutadiene structure contained in the polyol (a2) is contained. The compound (a3) is referred to as hydrogenated polybutadiene polyol (a3-2).

  The content of the hydrogenated polybutadiene structure-containing compound (a3) is preferably 0.001 to 15 mol%, and more preferably 0.005 to 10 mol% with respect to the total copolymerization components of the polyester resin (A). It is preferably in the range of 0.01 to 5 mol%, in particular 0.02 to 1 mol%. If the content is too small, the adhesiveness to the polyolefin adherend tends to decrease, and if it is too large, the compatibility tends to decrease.

  Examples of the hydrogenated polybutadiene structure-containing polyvalent carboxylic acids (a3-1) contained in the polyvalent carboxylic acids (a1) include, for example, 1,2-polybutadiene dicarboxylic acids, 1,4-polybutadiene dicarboxylic acids and 1,4- Examples thereof include polybutadiene-based polyvalent carboxylic acids such as polyisoprene dicarboxylic acids and saturated hydrocarbon-based polycarboxylic acids obtained by saturating the double bond of these polybutadiene-based polyvalent carboxylic acids with hydrogen or halogen. Further, polyvalent carboxylic acids obtained by copolymerizing polybutadiene-based polycarboxylic acids with olefin compounds such as styrene, ethylene, vinyl acetate, and acrylic acid esters, hydrogenated polycarboxylic acids thereof, and the like can also be used. Of these, particularly preferred are high-saturation hydrocarbon polybutadiene polycarboxylic acids having a number average molecular weight of 300 to 30,000, particularly 500 to 10,000, and more preferably 800 to 5,000. Further, those having an average functionality of the carboxy group of 1.5 to 3 are preferable.

  As the hydrogenated polybutadiene structure-containing polycarboxylic acid (a3-1), one having a large proportion of 1,2 bond sites in 1,2 bond sites and 1,4 bond sites in the hydrogenated polybutadiene structure. Is preferable in terms of excellent adhesiveness to a polyolefin substrate. Further, the 1,2 bond sites in the hydrogenated polybutadiene structure are preferably 25 to 100%, particularly preferably 50 to 100%, and particularly preferably 75 to 100%.

  The content of the hydrogenated polybutadiene structure-containing polycarboxylic acid (a3-1) is preferably 0.001 to 15 mol% based on all the copolymerization components of the polyester resin (A), and further, It is preferably 0.005 to 10 mol%, particularly 0.01 to 5 mol%, and especially 0.02 to 1 mol%. If the content is too small, the adhesiveness to the polyolefin adherend tends to decrease, and if it is too large, the compatibility tends to decrease.

  Further, as a constituent raw material of the polyester-based resin (A), it is more preferable to contain the hydrogenated polybutadiene structure-containing compound (a3) as the polyol (a2), and among them, the hydrogenated polybutadiene structure-containing compound is particularly preferable. (A3) is the hydrogenated polybutadiene polyol (a3-2) in the polyol (a2).

  Examples of the hydrogenated polybutadiene polyol (a3-2) include polybutadiene-based polyols such as 1,2-polybutadiene polyol, 1,4-polybutadiene polyol, and 1,4-polyisoprene polyol, or dual polybutadiene-based polyols thereof. Examples thereof include saturated hydrocarbon polyols whose bonds are saturated with hydrogen or halogen. Furthermore, a polyol obtained by copolymerizing a polybutadiene-based polyol with an olefin compound such as styrene, ethylene, vinyl acetate, or an acrylic ester, or a hydrogenated polyol thereof can be used. Among them, particularly preferred is a hydrocarbon-based polybutadiene polyol having a high degree of saturation, and the number average molecular weight is preferably 300 to 30,000, more preferably 500 to 10,000, and further preferably 800 to 5,000. It is preferable that the average functionality of the hydroxyl groups is 1.5 to 3.

  Further, as the hydrogenated polybutadiene polyol (a3-2), the one having a larger proportion of 1,2 bond sites in the 1,2 bond sites and the 1,4 bond sites in the hydrogenated polybutadiene structure is a polyolefin base material. It is preferable in terms of excellent adhesiveness. The 1,2 bond sites in the hydrogenated polybutadiene structure are preferably 25 to 100%, particularly preferably 50 to 100%, and particularly preferably 75 to 100%.

  The content of the hydrogenated polybutadiene polyol (a3-2) is preferably 0.001 to 15 mol%, and more preferably 0.005 to 10 mol%, based on all the copolymerization components of the polyester resin (A). It is preferably in the range of 0.01 to 5 mol%, in particular 0.02 to 1 mol%. If the content is too small, the adhesiveness to the polyolefin adherend tends to decrease, and if it is too large, the compatibility tends to decrease.

  The polyester resin (A) used in the present invention is produced by appropriately selecting the polyvalent carboxylic acids (a1) and the polyol (a2) and subjecting them to a polycondensation reaction by a known method in the presence of a catalyst. .

  In the polycondensation reaction, an esterification reaction is first performed, and then a polycondensation reaction is performed.

  In the esterification reaction, a catalyst is used, and specifically, for example, titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, antimony-based catalysts such as antimony trioxide, germanium-based catalysts such as germanium dioxide and the like. Examples thereof include catalysts and catalysts such as zinc acetate, manganese acetate and dibutyltin oxide, and one or more of these can be used. Among these, antimony trioxide, tetrabutyl titanate, germanium dioxide, and zinc acetate are preferable from the viewpoint of high catalytic activity and balance of hue.

  The amount of the catalyst blended is preferably 1 to 10,000 ppm, particularly preferably 10 to 5,000 ppm, and further preferably 20 to 3,000 ppm, based on all copolymerization components. If the amount is too small, the polymerization reaction tends not to proceed sufficiently, and if it is too large, there is no advantage such as shortening of the reaction time and side reactions tend to occur.

  The reaction temperature during the esterification reaction is preferably 200 to 300 ° C, particularly preferably 210 to 280 ° C, and further preferably 220 to 260 ° C. If the reaction temperature is too low, the reaction tends not to proceed sufficiently, and if it is too high, side reactions such as decomposition tend to occur. The pressure during the reaction is usually under normal pressure.

After the esterification reaction is performed, a polycondensation reaction is performed.
As the reaction conditions of the polycondensation reaction, the same catalyst as that used in the above esterification reaction is further mixed in the same amount, and the reaction temperature is preferably 220 to 280 ° C., particularly preferably 230 to 270 ° C. It is preferable that the system is gradually depressurized and finally reacted at 5 hPa or less. If the reaction temperature is too low, the reaction tends not to proceed sufficiently, and if it is too high, side reactions such as decomposition tend to occur.

  Thus, the polyester resin (A) used in the present invention is obtained. The polyester resin (A) has a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, and the content of the aromatic structure-containing compound in the polyvalent carboxylic acid and the weight average molecular weight are specific. It is in the range.

  The polyester-based resin (A) has a content of the aromatic structure-containing compound in the polyvalent carboxylic acid of 80 mol% or less from the viewpoint of adhesiveness to the substrate [I] and adhesiveness to a polyolefin adherend. is there. It is preferably 2 to 70 mol%, particularly preferably 3 to 60 mol%, and further preferably 5 to 40 mol%. When the content of the aromatic structure-containing compound in the polyvalent carboxylic acid is out of the above range, the adhesion with the base material [I] decreases.

  It is preferable that the polyester resin (A) further contains a structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3). The content of the structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3) in the polyester resin (A) is preferably 0.01 to 50% by weight, more preferably 0.1 to 30% by weight. %, Particularly preferably 0.2 to 20% by weight, further preferably 0.3 to 10% by weight. When the content of the structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3) is within the above range, the adhesion with the substrate [I] tends to be more excellent.

  The structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3) in the polyester resin (A) is at least one of a structural unit derived from the polycarboxylic acid (a1) and a structural unit derived from the polyol (a2). Is preferable from the viewpoint of adhesiveness to a polyolefin adherend, and more preferably it is contained as a structural unit derived from the polyol (a2).

  Further, when the structural unit derived from the hydrogenated polybutadiene polyol (a3-2) is included as the structural unit derived from the polyol (a2), the structural unit derived from the hydrogenated polybutadiene polyol (a3-2) is converted into the polyol (a2 From the viewpoint of compatibility, it is preferable to contain 0.001 to 30 mol% in the structural unit derived from), more preferably 0.01 to 20 mol%, particularly preferably 0.03 to 10 mol%, particularly preferably Is 0.04 to 5 mol%, 0.05 to 2 mol%, and 0.1 to 1 mol%.

  Further, the polyester resin (A) usually has a structural unit derived from the polyvalent carboxylic acid (a1) and a structural unit derived from the polyol (a2), but the aromatic polyvalent carboxylic acid, particularly an asymmetric aromatic polycarboxylic acid. When the structural unit derived from the carboxylic acid (a1-1) is contained as the structural unit derived from the polycarboxylic acid (a1), the structural unit derived from the asymmetric aromatic polycarboxylic acid (a1-1) is It is preferably 80 mol% or less in the structural unit derived from the polyvalent carboxylic acid (a1), particularly preferably 2 to 70 mol%, further preferably 3 to 60 mol%, particularly preferably 5 to 40 mol%. Is.

  When the structural unit derived from the aliphatic polycarboxylic acid (a1-2) having an odd number of carbon atoms is included as the structural unit derived from the polycarboxylic acid (a1), the aliphatic polycarboxylic acid having an odd carbon number is included. The structural unit derived from the acid (a1-2) is preferably contained in the structural unit derived from the polycarboxylic acid (a1) in an amount of 5 to 100 mol%, particularly preferably 10 to 100 mol%, and further preferably 20 to It is 100 mol%, particularly preferably 30 to 100 mol%.

  On the other hand, when the structural unit derived from the branched structure-containing polyol (a2-1) is included as the structural unit derived from the polyol (a2), the structural unit derived from the branched structure-containing polyol (a2-1) is the polyol (a2). It is preferable to contain 5 to 99 mol% in the structural unit derived from (4) from the viewpoint of impairing crystallinity, and particularly preferably 10 to 95 mol%, and further preferably 30 to 90 mol%.

  When the structural unit derived from the linear polyol (a2-2) is included as the structural unit derived from the polyol (a2), the structural unit derived from the linear polyol (a2-2) is derived from the polyol (a2). From the viewpoint of stable resin formation, it is preferable to contain 3 to 95 mol% in the structural unit of, more preferably 5 to 90 mol%, particularly preferably 10 to 80 mol%, particularly preferably 15 to 60 mol%. Is.

  Here, the structural unit ratio (composition ratio) derived from each component of the polyester resin (A) can be determined by, for example, NMR.

  The weight average molecular weight of the polyester resin (A) is 5,000 to 300,000 from the viewpoint of the cohesive force of the pressure-sensitive adhesive. It is preferably 8,000 to 200,000, particularly preferably 10,000 to 150,000, and further preferably 20,000 to 100,000. If the weight average molecular weight is too small, sufficient cohesive force as a pressure-sensitive adhesive cannot be obtained, and heat resistance and mechanical strength are likely to decrease. Further, if the weight average molecular weight is too large, gelation is likely to occur during the production of the polyester resin (A), the resin is difficult to obtain, and the adhesion to the substrate is lowered.

In addition, the weight average molecular weight of the present invention is a weight average molecular weight in terms of standard polystyrene molecular weight, and in a high performance liquid chromatograph ("HLC-8320GPC" manufactured by Tosoh Corporation), column: TSKgel SuperMultipore HZ-M (exclusion limit molecular weight: 2 × 10 ⁶ , theoretical plate number: 16,000 plates / line, filler material: styrene-divinylbenzene copolymer, filler particle size: 4 μm) are used in series to measure. The same method can be used for the number average molecular weight.

The ester bond concentration in the polyester resin (A) is usually 1 to 15 mmol / g, preferably 1.5 to 14 mmol / g, particularly preferably 2 to 13 mmol / g, and more preferably 3 to 12 mmol / g. g, more preferably 4 to 11 mmol / g, particularly preferably 5 to 10.5 mmol / g, preferably 6 to 10 mmol / g, and most preferably 7 to 9.5 mmol / g. If the ester bond concentration is too low, the storage elastic modulus tends to be low and the cohesive force tends to be low, and if the ester bond concentration is too high, the storage elastic modulus tends to be high and the adhesion tends to be low.
The ester bond concentration of the polyester resin (A) is calculated as the number of moles (mmol) of the acid component with respect to the weight (g) of the finished resin.
Ester bond concentration (mmol / g) = number of moles of acid component / weight of finished resin

  The glass transition temperature (Tg) of the polyester resin (A) is preferably −80 to 20 ° C., particularly preferably −70 to 15 ° C., further preferably −60 to 10 ° C., from the viewpoint of adhesive properties. is there. If the glass transition temperature (Tg) is too high, the flexibility is lost, the initial tackiness is lowered, the tackiness is less likely to be exerted under a pressure of about finger pressure, and the workability tends to be lowered. The force decreases, and the adhesive tape is likely to be deformed, which tends to impair the appearance.

Here, the glass transition temperature (Tg) of the polyester resin (A) is a value measured using a differential scanning calorimeter DSC Q20 manufactured by TA Instruments.
The measurement temperature range is −90 ° C. to 100 ° C., and the temperature rising rate is 10 ° C./minute.

  It is preferable that the polyester resin (A) is not crystallized from the viewpoint of storage stability, but even in the case of crystallization, it is preferable that the crystallization energy of the polyester resin (A) is as low as possible, usually 35 J / g. It is preferably 20 J / g or less, more preferably 10 J / g or less, and most preferably 5 J / g or less.

  The acid value of the polyester resin (A) is preferably 10 mgKOH / g or less, particularly 3 mgKOH / g or less, and further preferably 1 mgKOH / g or less. If the acid value is too high, it tends to corrode when a layer of metal or the like is attached to one surface of the pressure-sensitive adhesive layer. For example, when a metal oxide thin film layer is formed, corrosion tends to occur and the conductivity of the metal oxide thin film tends to decrease.

  Here, the acid value of the polyester resin (A) is obtained by neutralization titration based on JIS K0070.

[Hydrolysis inhibitor (B)]
The polyester-based pressure-sensitive adhesive composition [II] used in the present invention preferably contains a hydrolysis inhibitor (B) together with the polyester-based resin (A). The hydrolysis inhibitor (B) is contained to ensure long-term durability.

  As the hydrolysis inhibitor (B), conventionally known ones can be used, and examples thereof include compounds that react with and bind to the carboxylic acid terminal groups of the polyester resin (A). Examples of the compound include compounds having a functional group such as a carbodiimide group, an epoxy group, and an oxazoline group. Among these, the carbodiimide group-containing compound is preferable because it has a high effect of eliminating the catalytic activity of protons derived from the carboxy group terminal group.

  As the carbodiimide group-containing compound, a known polycarbodiimide having at least one carbodiimide group (-N = C = N-) in the molecule may be used, but the durability under higher temperature and high humidity is increased. From the viewpoint, a compound containing two or more carbodiimide groups in the molecule, that is, a polyvalent carbodiimide compound is preferable, and a compound containing three or more, particularly five or more, and particularly seven or more is preferable. It is preferable. If 30 or more is contained, the molecular structure becomes too large, which is not preferable. Further, as the carbodiimide group-containing compound, it is also preferable to use a high molecular weight polycarbodiimide produced by a decarboxylation condensation reaction of diisocyanate in the presence of a carbodiimidization catalyst.

  Examples of such a high molecular weight polycarbodiimide include those obtained by subjecting the following diisocyanates to a decarboxylation condensation reaction.

  Examples of such diisocyanates include 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′- Diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4, 4'-dicyclohexyl methane diisocyanate, tetramethyl xylylene diisocyanate, etc. are mentioned, These can be used individually or in combination of 2 or more types. Such high molecular weight polycarbodiimide may be synthesized or a commercially available product may be used.

  Examples of commercially available carbodiimide group-containing compounds include carbodilite (registered trademark) series manufactured by Nisshinbo Chemical Co., Ltd. Among them, carbodilite (registered trademark) V-01, V-02B, V-03, and V. -04K, V-04PF, V-05, V-07, V-09, and V-09GB are preferable because of their excellent compatibility with organic solvents.

  The epoxy group-containing compound is preferably, for example, a glycidyl ester compound or a glycidyl ether compound.

  Specific examples of the glycidyl ester compound include, for example, benzoic acid glycidyl ester, t-Bu-benzoic acid glycidyl ester, p-toluic acid glycidyl ester, cyclohexanecarboxylic acid glycidyl ester, pelargonic acid glycidyl ester, stearic acid glycyl ester, and lauric acid. Glycidyl ester, palmitic acid glycidyl ester, behenic acid glycidyl ester, versatic acid glycidyl ester, oleic acid glycidyl ester, linoleic acid glycidyl ester, linoleic acid glycidyl ester, behenolic acid glycidyl ester, stearolic acid glycidyl ester, terephthalic acid diglycidyl ester, Isophthalic acid diglycidyl ester, phthalic acid diglycidyl ester, naphthalene dicarboxylic acid diglycy Ester, methyl terephthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, cyclohexanedicarboxylic acid diglycidyl ester, adipic acid diglycidyl ester, succinic acid diglycidyl ester, sebacic acid diglycidyl ester, dodecane Examples thereof include diacid diglycidyl ester, octadecane dicarboxylic acid diglycidyl ester, trimellitic acid triglycidyl ester, pyromellitic acid tetraglycidyl ester, and these may be used alone or in combination of two or more kinds.

  Specific examples of the glycidyl ether compound include, for example, phenylglycidyl ether, o-phenylglycidyl ether, 1,4-bis (β, γ-epoxypropoxy) butane, 1,6-bis (β, γ- Epoxypropoxy) hexane, 1,4-bis (β, γ-epoxypropoxy) benzene, 1- (β, γ-epoxypropoxy) -2-ethoxyethane, 1- (β, γ-epoxypropoxy) -2- Benzyloxyethane, 2,2-bis- [р- (β, γ-epoxypropoxy) phenyl] propane and 2,2-bis- (4-hydroxyphenyl) propane and 2,2-bis- (4-hydroxyphenyl) ) Bisglycidyl polyether obtained by the reaction of bisphenol such as methane with epichlorohydrin, and the like, and these may be used alone or in combination of two or more. It can be used in combination.

  The oxazoline group-containing compound is preferably a bisoxazoline compound or the like. Specifically, for example, 2,2′-bis (2-oxazoline), 2,2′-bis (4-methyl-2-oxazoline), 2,2′-bis (4,4-dimethyl-2-) Oxazoline), 2,2'-bis (4-ethyl-2-oxazoline), 2,2'-bis (4,4'-diethyl-2-oxazoline), 2,2'-bis (4-propyl-2) -Oxazoline), 2,2'-bis (4-butyl-2-oxazoline), 2,2'-bis (4-hexyl-2-oxazoline), 2,2'-bis (4-phenyl-2-oxazoline) ), 2,2′-bis (4-cyclohexyl-2-oxazoline), 2,2′-bis (4-benzyl-2-oxazoline), 2,2′-p-phenylenebis (2-oxazoline), 2 , 2'-m-phenylene bis (2-oxazoline), , 2'-o-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2'-p-phenylenebis (4,4-dimethyl-2) -Oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2,2'-m-phenylenebis (4,4-dimethyl-2-oxazoline), 2,2'-ethylene Bis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2'-hexamethylenebis (2-oxazoline), 2,2'-octamethylenebis (2-oxazoline), 2 , 2'-Decamethylenebis (2-oxazoline), 2,2'-ethylenebis (4-methyl-2-oxazoline), 2,2'-tetramethylenebis (4,4-dimethyl-2-oxa) Phosphorus), 2,2'-9,9'-diphenoxyethanebis (2-oxazoline), 2,2'-cyclohexylenebis (2-oxazoline), 2,2'-diphenylenebis (2-oxazoline) And the like, and of these, 2,2′-bis (2-oxazoline) is most preferable from the viewpoint of reactivity with the polyester resin (A). Further, these may be used alone or in combination of two or more kinds.

As these hydrolysis inhibitors (B), those having a low volatility are preferable, and therefore those having a high number average molecular weight are preferably used, and usually 300 to 10,000, preferably 1,000 to 5,000. Use the one.
As the hydrolysis inhibitor (B), it is preferable to use one having a high weight average molecular weight from the viewpoint of hydrolysis resistance. The weight average molecular weight of the hydrolysis inhibitor (B) is preferably 500 or more, more preferably 2,000 or more, and further preferably 3,000 or more. The upper limit of the weight average molecular weight is usually 50,000, preferably 10,000.
If the molecular weight of the hydrolysis inhibitor (B) is too small, the hydrolysis resistance tends to decrease. If the molecular weight is too large, the compatibility with the polyester resin (A) tends to decrease.

  Among the hydrolysis inhibitors (B), it is preferable to use a carbodiimide group-containing compound, and the carbodiimide equivalent at that time is preferably 50 to 10,000, particularly 100 to 1,000, and further 150. It is preferably about 500. The carbodiimide equivalent means the chemical formula weight per carbodiimide group.

  The content of the hydrolysis inhibitor (B) is preferably 0.01 to 10 parts by weight, and particularly preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polyester resin (A). , And more preferably 0.2 to 3 parts by weight. If the content is too large, turbidity tends to occur due to poor compatibility with the polyester resin (A), and if it is too small, sufficient durability tends to be difficult to obtain.

The content of the hydrolysis inhibitor (B) is preferably optimized in accordance with the acid value of the polyester resin (A), and the content of the polyester resin (A The molar ratio ((b) / (a)) of the total number (b) of the functional groups of the hydrolysis inhibitor (B) in the pressure-sensitive adhesive composition to the total number (m) of the acidic functional groups of , 0.5 ≦ (b) / (a), particularly preferably 1 ≦ (b) / (a) ≦ 1,000, further preferably 1.5 ≦ (b) / (a) ≦ 100.
If the molar ratio of (b) to (a) is too low, the moist heat resistance tends to decrease. If the molar ratio of (b) to (a) is too high, the compatibility with the polyester resin (A) tends to decrease, and the adhesive force, cohesive force, and durability performance tend to decrease.

[Urethane-forming catalyst (C)]
The polyester-based pressure-sensitive adhesive composition [II] used in the present invention contains the above polyester-based resin (A), and preferably contains the above hydrolysis inhibitor (B). It is more preferable to contain a chemical catalyst (C).

  Examples of the urethanization catalyst (C) include organometallic compounds and tertiary amine compounds. These can be used alone or in combination of two or more.

Examples of the organometallic compounds include zirconium compounds, iron compounds, tin compounds, titanium compounds, lead compounds, cobalt compounds, zinc compounds, and the like.
Examples of zirconium compounds include zirconium naphthenate and zirconium acetylacetonate.
Examples of the iron-based compound include iron acetylacetonate and iron 2-ethylhexanoate.
Examples of the tin-based compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dilaurate and the like.
Examples of titanium compounds include dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride, and the like.
Examples of the lead-based compound include lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, and the like.
Examples of the cobalt-based compound include cobalt 2-ethylhexanoate and cobalt benzoate.
Examples of zinc compounds include zinc naphthenate and zinc 2-ethylhexanoate.

  Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo- (5,4,0) -undecene-7 and the like.

  Among these urethanization catalysts (C), organometallic compounds are preferable, and zirconium compounds are particularly preferable, from the viewpoint of reaction rate and pot life of the pressure-sensitive adhesive layer. Further, the urethanization catalyst (C) is preferably used in combination with acetylacetone as a catalytic action inhibitor. The inclusion of acetylacetone is preferable in that the catalytic action at low temperature is suppressed and the pot life is extended.

[Crosslinking agent (D)]
The polyester-based pressure-sensitive adhesive composition [II] used in the present invention contains the above-mentioned polyester-based resin (A), preferably a hydrolysis inhibitor (B), but is usually a crosslinking agent (D). It is preferable that the polyester resin (A) is further cross-linked with the cross-linking agent (D) by adding the cross-linking agent (D), and the cohesive force is excellent and the performance as an adhesive is improved. be able to.

  Examples of the cross-linking agent (D) include compounds having a functional group that reacts with at least one of the hydroxyl group and the carboxy group contained in the polyester resin (A), such as polyisocyanate compounds and polyepoxy compounds. Among these, it is particularly preferable to use a polyisocyanate compound from the viewpoint that the initial tackiness, mechanical strength, and heat resistance can be well balanced.

  Examples of the polyisocyanate compound include, for example, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, 1 , 5-naphthalene diisocyanate, triphenylmethane triisocyanate, and the like. Further, an adduct of the above polyisocyanate and a polyol compound such as trimethylolpropane, a burette of these polyisocyanate-based compounds, and isocyanate are included. Examples include nurate and the like. The polyisocyanate-based compound may be used in which the isocyanate moiety is blocked with phenol, lactam or the like. These crosslinking agents (D) may be used alone or in combination of two or more.

The content of the cross-linking agent (D) can be appropriately selected depending on the molecular weight of the polyester resin (A) and the purpose of use, but usually 1 equivalent of at least one of the hydroxyl group and the carboxy group contained in the polyester resin (A). On the other hand, the reactive group contained in the cross-linking agent (D) preferably contains the cross-linking agent (D) in a ratio of 0.2 to 10 equivalents, particularly preferably 0.5 to 5 equivalents, It is preferably 0.5 to 3 equivalents.
If the number of equivalents of the reactive group contained in the crosslinking agent (D) is too small, the cohesive force tends to decrease, and if it is too large, the flexibility tends to decrease.

  In the reaction between the polyester resin (A) and the crosslinking agent (D), an organic solvent having no functional group that reacts with the components (A) and (D), for example, esters such as ethyl acetate and butyl acetate. Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene can be used. These can be used alone or in combination of two or more.

  The polyester-based pressure-sensitive adhesive composition [II] used in the present invention is, in addition to the above-mentioned polyester resin (A), hydrolysis inhibitor (B), urethanization catalyst (C), and crosslinking agent (D), Additives such as antioxidants (E) such as hindered phenols, softeners, ultraviolet absorbers, stabilizers, antistatic agents, tackifiers, etc., other than inorganic or organic, as long as the effects of the present invention are not impaired. The above-mentioned filler, powdered particles such as metal powders and pigments, and additives such as particles can be added. These can be used alone or in combination of two or more.

  The polyester-based pressure-sensitive adhesive used in the present invention is composed of the polyester-based pressure-sensitive adhesive composition [II], that is, the polyester-based pressure-sensitive adhesive composition [II] is cured.

<Adhesive tape>
The pressure-sensitive adhesive tape of the present invention can be produced using the above-mentioned substrate [I] and polyester-based pressure-sensitive adhesive composition [II], for example, as follows.
As a method for producing such an adhesive tape, it can be produced according to a publicly-known general method for producing an adhesive tape. For example, the above polyester-based adhesive composition [II] is applied onto a substrate [I] and dried. , A pressure-sensitive adhesive comprising a polyester-based pressure-sensitive adhesive on the substrate [I] by bonding a release sheet (or a release film) on the surface of the polyester-based pressure-sensitive adhesive composition [II] layer and curing as necessary. The adhesive tape of the present invention having layers is obtained.

  Further, the polyester-based pressure-sensitive adhesive composition [II] is applied onto a release sheet, dried, and the substrate [I] is attached to the surface of the polyester-based pressure-sensitive adhesive composition [II] layer, if necessary. The adhesive tape of the present invention can also be obtained by curing.

  Furthermore, the pressure-sensitive adhesive tape of the present invention may be a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of a polyester-based pressure-sensitive adhesive on both surfaces of the substrate [I].

  Examples of the release sheet include polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate and polyethylene terephthalate / isophthalate copolymers; polyolefin resins such as polyethylene, polypropylene and polymethylpentene; polyvinyl fluoride. , Polyvinylidene fluoride, polyfluorinated ethylene resins such as polyfluorinated ethylene; polyamides such as nylon 6, nylon 6,6; polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymers, ethylene-vinyl acetate copolymers, ethylene- Vinyl polymers such as vinyl alcohol copolymer, polyvinyl alcohol and vinylon; cellulose resins such as cellulose triacetate and cellophane; polymethylmethacrylate, polyethylmethacrylate, polyacrylic acid Acrylic resin such as chill and polybutyl acrylate; polystyrene; polycarbonate; polyarylate; polyimide; sheet made of synthetic resin such as cycloolefin polymer, metal foil of aluminum, copper, iron, high-quality paper, paper such as glassine paper, A woven fabric or non-woven fabric made of glass fiber, natural fiber, synthetic fiber or the like, which has been subjected to a release treatment, can be used. A silicone-based release sheet is preferably used as the release sheet.

  As a coating method of the above polyester-based pressure-sensitive adhesive composition [II], for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater or the like may be used. Good.

  As the conditions for the curing treatment, the temperature is usually room temperature (23 ° C.) to 70 ° C., and the time is usually 1 to 30 days. Specifically, for example, 23 ° C. for 1 to 20 days, preferably 23 ° C. for 3 days. It may be carried out under conditions such as ˜14 days, 40 ° C. and 1 to 10 days.

  As the drying conditions, the drying temperature is preferably 60 to 140 ° C., particularly preferably 80 to 120 ° C., and the drying time is preferably 0.5 to 30 minutes, particularly preferably 1 to 5 minutes.

  The pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape preferably has a thickness of 2 to 500 μm, particularly preferably 5 to 200 μm, and further preferably 10 to 100 μm. If the thickness of the pressure-sensitive adhesive layer is too thin, the adhesive strength tends to decrease, and if it is too thick, it becomes difficult to apply it uniformly, and there is a tendency that problems such as bubbles in the coating film easily occur. is there. When considering impact absorption, the thickness is preferably 50 μm or more.

  The thickness of the pressure-sensitive adhesive layer is obtained by subtracting the measured value of the thickness of the constituent members other than the pressure-sensitive adhesive layer from the measured value of the thickness of the entire pressure-sensitive adhesive tape using "ID-C112B" manufactured by Mitutoyo Corporation. .

  When the thickness of the substrate [I] is 100, the thickness of the pressure-sensitive adhesive layer is usually 5 to 100, preferably 10 to 50. If the above ratio is too low, the adhesive strength tends to decrease, and if the ratio is too high, it becomes difficult to apply the adhesive layer uniformly, and problems such as bubbles entering the coating film occur. Tends to be easy.

  The gel fraction of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is preferably 10% by weight or more, particularly preferably 15 to 95% by weight, further preferably 20 to 90% by weight, from the viewpoint of durability and adhesive strength. is there. If the gel fraction is too low, the cohesive force will decrease and the durability will tend to decrease. If the gel fraction is too high, the cohesive force will increase and the adhesive force will tend to decrease.

  The gel fraction is a measure of the degree of crosslinking, and is calculated by the following method, for example. That is, a pressure-sensitive adhesive tape (having no release sheet) formed by forming a pressure-sensitive adhesive layer on the base material [I] is wrapped with a 200-mesh SUS wire mesh, dipped in toluene at 23 ° C. for 24 hours, and dipped. The weight percentage of the insoluble adhesive component remaining in the wire mesh after the immersion with respect to the weight of the previous adhesive component is taken as the gel fraction. However, the weight of the base material [I] is subtracted.

  Furthermore, such an adhesive tape may be protected by providing a release sheet on the outside of the adhesive layer, if necessary. Further, in the pressure-sensitive adhesive tape in which the pressure-sensitive adhesive layer is formed on one surface of the substrate [I], the surface of the substrate [I] opposite to the pressure-sensitive adhesive layer is subjected to a peeling treatment to remove the peeled surface. It is also possible to utilize and protect the adhesive layer.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, “part” means weight basis.

  Prior to the production of the pressure-sensitive adhesive tape, the following urethane-based resin foam base material was prepared as the base material [I]. The apparent density and the thickness of the urethane resin foam base material were the catalog values of the manufacturer, and the tensile strength and the elongation rate were measured according to the methods described above.

<Urethane resin foam base material>
-I-1: urethane resin foam base material (apparent density 400 kg / m ³ , thickness 0.5 mm)
-I-2: urethane resin foam base material (apparent density 480 kg / m ³ , thickness 0.3 mm)
-I-3: urethane resin foam substrate (apparent density 600 kg / m ³ , tensile strength 0.84 MPa, elongation 97%, thickness 0.7 mm)
-I-4: urethane resin foam substrate (apparent density 600 kg / m ³ , tensile strength 0.6 MPa, elongation 127%, thickness 1 mm)
I-5: Urethane resin foam substrate (apparent density 700 kg / m ³ , tensile strength 1.1 MPa, elongation 100%, thickness 0.2 mm)
I-6: Urethane-based resin foam substrate (apparent density 150 kg / m ³ , tensile strength 0.5 MPa, elongation 335%, thickness 0.5 mm)

<Production of polyester resin (A)>
Next, a polyester resin was prepared.
The mol% described in the following production examples means a mol ratio when the total amount of the polyvalent carboxylic acids (a1) is 100 mol%. The glass transition temperature, weight average molecular weight, and ester bond concentration of the polyester resin were measured according to the methods described above.

[Production of Polyester Resin (A-1)]
In a reaction can equipped with a heating device, a thermometer, a stirrer, a rectification column, a nitrogen introduction tube and a vacuum device, 66.3 parts (20 mol%) of isophthalic acid (IPA) and sebacine as polycarboxylic acid (a1) were added. 322.9 parts (80 mol%) of acid (SebA), 207.9 parts (100 mol%) of neopentyl glycol (NPG) as polyol (a2), 89.9 parts of 1,4-butanediol (1,4BG). (50 mol%), trimethylolpropane (TMP) 4.0 parts (1.5 mol%), and hydrogenated polybutadiene polyol (manufactured by Nippon Soda Co., Ltd., “GI-1000”) as the hydrogenated polybutadiene structure-containing compound (a3). ) 9.0 parts (0.3 mol%) and 0.05 part of zinc acetate as a catalyst were charged, the temperature was gradually raised to an internal temperature of 250 ° C., and the esterification reaction was carried out for 4 hours.
Then, the internal temperature was raised to 260 ° C., 0.05 parts of tetrabutyl titanate was charged as a catalyst, the pressure was reduced to 1.33 hPa, and the polymerization reaction was carried out for 3 hours to produce a polyester resin (A-1).
The glass transition temperature of the obtained polyester resin (A-1) is −46.8 ° C., and the structural unit ratio derived from the finished component (hereinafter, may be abbreviated as “finished component ratio”) is a polyvalent carboxylic acid ( a1) isophthalic acid / sebacic acid = 20 mol% / 80 mol%, and polyol (a2) neopentyl glycol / 1,4-butanediol / trimethylolpropane / hydrogenated polybutadiene polyol = 64.5 mol% / 33. It was 7 mol% / 1.5 mol% / 0.3 mol%.
The content of the structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3) in the polyester resin (A-1) was 1.7% by weight, the weight average molecular weight was 73,000, and the ester bond concentration was 7. It was 6 mmol / g.

<Production of polyester-based pressure-sensitive adhesive composition [II]>
A polyester-based pressure-sensitive adhesive composition [II] was produced using the polyester-based resin (A-1) obtained above.

(Production of Polyester Adhesive Composition [II-1])
The polyester resin (A-1) obtained above is diluted with toluene to a solid content concentration of 50%, and hydrolysis is suppressed with respect to 200 parts of this polyester resin (A-1) solution (100 parts as solid content). Agent (manufactured by Nisshinbo Chemical Inc., "Carbodilite V-09GB") 1 part (solid content), and 2 parts (solid content) of trimethylolpropane / tolylene diisocyanate adduct (Tosoh Corp., "Coronate L55E") as a crosslinking agent. By mixing 0.01 parts (solid content) of a zirconium compound (“Organix ZC-150” manufactured by Matsumoto Fine Chemical Co., Ltd.) diluted with acetylacetone as a urethane-forming catalyst to a solid content concentration of 1%, stirring and mixing, A polyester-based pressure-sensitive adhesive composition [II-1] was obtained.

  In addition, as a pressure-sensitive adhesive that is generally used for pressure-sensitive adhesive tapes, an acrylic pressure-sensitive adhesive composition [II ′] was manufactured according to the following method.

<Manufacture of acrylic resin>
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer, 91.9 parts of butyl acrylate, 8 parts of acrylic acid, 0.1 part of hydroxyethyl methacrylate and 80 parts of ethyl acetate. Was charged, and after heating under reflux, 0.5 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and after reacting at ethyl acetate reflux temperature for 7 hours, it was diluted with ethyl acetate to give an acrylic resin solution. Manufactured.
The obtained acrylic resin had a glass transition temperature of −46 ° C. and a weight average molecular weight of 750,000. The glass transition temperature is calculated using the Fox equation, and the weight average molecular weight is measured by the same method as for the polyester resin.

(Production of acrylic pressure-sensitive adhesive composition [II '])
To 285 parts (100 parts as solid content) of the acrylic resin solution obtained above, 1 part (solid content) of trimethylolpropane / tolylene diisocyanate adduct ("Coronate L55E" manufactured by Tosoh Corporation) as a cross-linking agent Then, the mixture was stirred and mixed to obtain an acrylic pressure-sensitive adhesive composition [II ′].

<Preparation of adhesive tape>
Using the substrate [I], the polyester-based pressure-sensitive adhesive composition [II-1], and the acrylic-based pressure-sensitive adhesive composition [II '], pressure-sensitive adhesive tapes of Examples 1 to 6 and Comparative Examples 1 and 2 were obtained. It was made.

[Example 1]
The polyester pressure-sensitive adhesive composition [II-1] was applied onto a PET release film having a thickness of 38 μm (“SP-PET-03-BU” manufactured by Mitsui Chemicals Tohcello) using an applicator, and 100 ° C. After drying for 4 minutes, a pressure-sensitive adhesive sheet with a release film having a pressure-sensitive adhesive composition layer thickness of 50 μm was obtained.
Then, the surface of the pressure-sensitive adhesive composition layer of the obtained pressure-sensitive adhesive sheet with a release film was transfer-coated on a urethane resin foam substrate [I-1] (apparent density 400 kg / m ³ , thickness 0.5 mm), and 40 Aging treatment was performed at 4 ° C. for 4 days to obtain an adhesive tape with a one-sided release film.

[Example 2]
Same as Example 1 except that the urethane resin foam substrate [I-1] was changed to urethane resin foam substrate [I-2] (apparent density 480 kg / m ³ , thickness 0.3 mm). The adhesive tape of Example 2 was obtained.

[Example 3]
Same as Example 1 except that the urethane resin foam substrate [I-1] is changed to urethane resin foam substrate [I-3] (apparent density 600 kg / m ³ , thickness 0.7 mm). The adhesive tape of Example 3 was obtained.

[Example 4]
Example 1 was repeated except that the urethane resin foam substrate [I-1] was changed to the urethane resin foam substrate [I-4] (apparent density 600 kg / m ³ , thickness 1 mm). The adhesive tape of Example 4 was obtained.

[Example 5]
Same as Example 1 except that the urethane resin foam substrate [I-1] is changed to urethane resin foam substrate [I-5] (apparent density 700 kg / m ³ , thickness 0.2 mm). The adhesive tape of Example 5 was obtained.

[Example 6]
Same as Example 1 except that the urethane resin foam substrate [I-1] is changed to urethane resin foam substrate [I-6] (apparent density 150 kg / m ³ , thickness 0.5 mm). The adhesive tape of Example 6 was obtained.

[Comparative Example 1]
A pressure-sensitive adhesive tape of Comparative Example 1 was obtained in the same manner as in Example 1 except that the urethane resin foam substrate [I-1] was changed to a PET film (Lumirror T60 manufactured by Toray Industries, Inc., thickness 38 μm).

[Comparative Example 2]
In Example 1, the polyester-based pressure-sensitive adhesive composition [II-1] was replaced with the acrylic-based pressure-sensitive adhesive composition [II '], and the urethane-based resin foam substrate [I-1] was replaced with the urethane-based resin foam substrate [I-]. The adhesive tape of Comparative Example 2 was obtained in the same manner except that the adhesive tape was changed to [5].

  Using the pressure-sensitive adhesive tapes of Examples 1 to 6 and Comparative Examples 1 and 2 obtained above, the peel strength to the polypropylene adherend was measured.

<Peel strength against adherends of polypropylene>
In an environment of 23 ° C. and 50% RH, the adhesive tape was cut into a size of 25 mm × 200 mm, the release film was peeled off, and a pressure-sensitive adhesive layer was attached to the polypropylene plate by reciprocating a 2 kg roller. After leaving it in the atmosphere for 90 minutes, 180 degree peel strength (N / 25 mm) was measured at a peel speed of 300 mm / min using an autograph (“Autograph AGS-H 500N” manufactured by Shimadzu Corporation). The results are shown in Table 1 below.

From the results shown in Table 1 above, the adhesive tapes of Examples 1 to 6 were excellent in peel strength with respect to the polypropylene adherend. This means that the pressure-sensitive adhesive tapes of Examples 1 to 6 have excellent adhesiveness between the urethane-based resin foam base material and the polyester-based adhesive layer and adhesiveness between the polyester-based adhesive layer and the polypropylene adherend. To do.
In contrast, Comparative Example 1 using the PET base material and Comparative Example 2 using the acrylic pressure-sensitive adhesive were inferior in peel strength to the polypropylene adherend as compared with Examples 1 to 6. . From this, it can be seen that the adhesive property is more excellent by using the constitution of the adhesive tape using the polyurethane foam substrate and the polyester adhesive.

  Since the pressure-sensitive adhesive tape of the present invention has excellent adhesion between the polyester-based pressure-sensitive adhesive layer and the urethane-based resin foam base material or the acrylic-based resin foam base material, it can be suitably used for various bonding applications.

Claims (6)

  A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer made of a polyester-based pressure-sensitive adhesive on at least one surface of a substrate [I], wherein the substrate [I] is a urethane-based resin foam substrate or an acrylic-based resin foam substrate. The polyester pressure-sensitive adhesive has a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, the content of the aromatic structure-containing compound in the polyvalent carboxylic acid is 80 mol% or less, and the weight average molecular weight. Is a pressure-sensitive adhesive formed from a polyester-based pressure-sensitive adhesive composition [II] containing a polyester-based resin (A) having a viscosity of 5,000 to 300,000. The adhesive tape according to claim 1, wherein the urethane resin foam base material or the acrylic resin foam base material has an apparent density of 100 to 1,000 kg / m ³ .   The pressure-sensitive adhesive tape according to claim 1, wherein the polyester resin (A) has a structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3).   The pressure-sensitive adhesive tape according to claim 3, wherein the content of the structural unit derived from the hydrogenated polybutadiene structure-containing compound (a3) is 0.01 to 50% by weight of the polyester resin (A).   The pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein the polyester-based pressure-sensitive adhesive composition [II] further contains a hydrolysis inhibitor.   The pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein the substrate [I] has a thickness of 0.1 to 2 mm.