WO2022165621A1 - Adhesive, laminate, and packaging material - Google Patents

Adhesive, laminate, and packaging material Download PDF

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Publication number
WO2022165621A1
WO2022165621A1 PCT/CN2021/074794 CN2021074794W WO2022165621A1 WO 2022165621 A1 WO2022165621 A1 WO 2022165621A1 CN 2021074794 W CN2021074794 W CN 2021074794W WO 2022165621 A1 WO2022165621 A1 WO 2022165621A1
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WO
WIPO (PCT)
Prior art keywords
polyester polyol
acid
polyol
mass
adhesive
Prior art date
Application number
PCT/CN2021/074794
Other languages
French (fr)
Inventor
Tsukiko Hosono
Makoto Kamimura
Feng Zhao
Xuewei Li
Ruiyu Si
Zhiqiang Liu
Original Assignee
Dic Corporation
Feng Zhao
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dic Corporation, Feng Zhao filed Critical Dic Corporation
Priority to CN202180091439.8A priority Critical patent/CN116761867A/en
Priority to PCT/CN2021/074794 priority patent/WO2022165621A1/en
Priority to JP2022509661A priority patent/JP7380842B2/en
Publication of WO2022165621A1 publication Critical patent/WO2022165621A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
    • C08G18/751—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring
    • C08G18/752—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group
    • C08G18/753—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group
    • C08G18/755—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4202—Two or more polyesters of different physical or chemical nature
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4205—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups
    • C08G18/4208—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups
    • C08G18/4211—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols
    • C08G18/4216—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols from mixtures or combinations of aromatic dicarboxylic acids and aliphatic dicarboxylic acids and dialcohols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4205—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups
    • C08G18/4208—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups
    • C08G18/4211—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols
    • C08G18/4219—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols from aromatic dicarboxylic acids and dialcohols in combination with polycarboxylic acids and/or polyhydroxy compounds which are at least trifunctional
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4236—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups
    • C08G18/4238—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups derived from dicarboxylic acids and dialcohols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/721—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80
    • C08G18/725—Combination of polyisocyanates of C08G18/78 with other polyisocyanates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
    • C08G18/78—Nitrogen
    • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
    • C08G18/791—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups
    • C08G18/792—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes
    • C09J175/06—Polyurethanes from polyesters

Definitions

  • the present invention relates to an adhesive, to a laminate obtained using the adhesive, to a method for producing the laminate, and to a packaging material.
  • Laminated films used for various packaging materials, labels, etc. are produced by laminating various plastic films, metal foils, paper sheets, etc. to impart designs, functionality, shelf life, convenience, and transportability thereto.
  • packages produced by forming laminated films into a bag shape are used for food products, medical and pharmaceutical products, detergents, etc.
  • Conventional laminated films are mainly obtained by a dry lamination method including coating a film with a two-part curable adhesive prepared by dissolving a polyisocyanate compound and a polyol compound in a volatile organic solvent, causing the resulting film to pass through an oven to volatilize the organic solvent, and then laminating another film onto the resulting film.
  • a two-part curable solventless adhesive containing a polyisocyanate compound and a polyol compound that do not contain a volatile organic solvent (PTL 1 and PTL 2) .
  • the polyisocyanate compound and the polyol compound used in the solventless adhesive must have a viscosity low enough to allow the adhesive to be applied without dilution with an organic solvent, unlike those in solvent-type adhesives. Therefore, these polyisocyanate and polyol compounds inevitably have low molecular weights. When the molecular weights of the polyisocyanate and polyol compounds are low, the initial cohesion of the adhesive is low, and problems such as tunnel-like delamination starting from an edge of a laminated film (tunneling) and displacement of bonding surfaces of a rolled laminated film (Winding Deviation) may occur. It is contemplated to increase the molecular weights of the polyisocyanate and polyol compounds to some extent and apply them at high temperature. However, in this case, damage to the films is large.
  • the present invention has been made in view of the above circumstances, and it is an object to provide a solventless adhesive having high initial cohesion and suitable for non-solvent lamination.
  • the present invention relates to a two-part adhesive containing a polyisocyanate composition (A) and a polyol composition (B) , wherein the polyol composition (B) contains a crystalline polyester polyol (B1) having a melting point of from 50°C to 70°C inclusive and an amorphous polyester polyol (B2) having an average functionality of from 2.01 to 2.2 inclusive, wherein the amount of the polyester polyol (B1) relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2) is from 15%by mass to 85%by mass inclusive, and wherein the amount of the polyester polyol (B2) relative to the total amount is from 15%by mass to 85%by mass inclusive.
  • the present invention also relates to a laminate obtained using the two-part adhesive and to a packaging material obtained using the two-part adhesive.
  • the present invention can provide an adhesive which has high initial cohesion, in which tunneling and telescoping are prevented, and which is suitable for non-solvent lamination.
  • the adhesive of the present invention is a two-part adhesive containing a polyisocyanate composition (A) and a polyol composition (B) .
  • the adhesive of the present invention will be described in detail.
  • the polyisocyanate composition (A) used in the adhesive of the present invention contains a polyisocyanate compound (A1) .
  • a polyisocyanate compound (A1) No particular limitation is imposed on the polyisocyanate compound (A1) , and any well-known polyisocyanate compound can be used.
  • the polyisocyanate compound (A1) include: aromatic polyisocyanates; araliphatic polyisocyanates; aliphatic polyisocyanates; alicyclicpolyisocyanates; biurets, nurates, adducts, and allophanates of these polyisocyanates; carbodiimide-modified isocyanates; and urethane prepolymers obtained by reacting polyisocyanates with polyols. Any of these may be used alone or in combination of two or more.
  • aromatic polyisocyanates examples include, but not limited to, 2, 2′-diphenylmethane diisocyanate, 2, 4′-diphenylmethane diisocyanate, 4, 4′-diphenylmethane diisocyanate, 1, 3-phenylene diisocyanate, 4, 4′-diphenyl diisocyanate, 1, 4-phenylene diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4, 4′-toluidine diisocyanate, 2, 4, 6-triisocyanate toluene, 1, 3, 5-triisocyanate benzene, dianisidine diisocyanate, 4, 4′-diphenyl ether diisocyanate, and 4, 4′, 4"-triphenylmethane triisocyanate.
  • the araliphatic polyisocyanate means an aliphatic isocyanate having at least one aromatic ring in its molecule, and examples thereof include, but not limited to, m-and p-xylylene diisocyanates and ⁇ , ⁇ , ⁇ ′, ⁇ ′-tetramethylxylylene diisocyanate.
  • aliphatic polyisocyanate examples include, but not limited to, trimethylene diisocyanate, 1, 2-propylene diisocyanate, tetramethylene diisocyanate, 1, 3-butylene diisocyanate, 2, 3-butylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2, 4, 4-trimethylhexamethylene diisocyanate, and dodecamethylene diisocyanate.
  • alicyclic polyisocyanates examples include, but not limited to, isophorone diisocyanate, 1, 3-cyclopentane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, methyl-2, 4-cyclohexane diisocyanate, methyl-2, 6-cyclohexane diisocyanate, 4, 4′-methylenebis (cyclohexyl isocyanate) , and 1, 4-bis (isocyanatomethyl) cyclohexane.
  • Examples of the polyol used for the synthesis of the urethane prepolymer include: alkylene glycols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, 1, 4-cyclohexanediol, and 1, 4-cyclohexanedimethanol;
  • alkylene glycols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glyco
  • bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F;
  • polyalkylene glycols such as diethylene glycol, triethylene glycol, other polyethylene glycols, polypropylene glycols, and polybutylene glycols;
  • urethane bond-containing polyether polyols obtained by further increasing the molecular weights of the polyalkylene glycols with aromatic or aliphatic polyisocyanates;
  • polyester polyols obtained by reacting alkylene glycols or polyalkylene glycols with at least one of aliphatic dicarboxylic acids having 2 to 13 carbon atoms such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and tridecanedioic acid and aromatic polycarboxylic acids such as ortho-phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid; and polyester polyols that are reaction products of polyesters obtained by a ring-opening polymerization reaction of cyclic ester compounds such as propiolactone, butyrolactone, ⁇ -caprolactone, ⁇ -valerolactone, and ⁇ -methyl- ⁇ -valerolactone with polyhydric alcohol
  • the polyol composition (B) used in the adhesive of the present invention contains the crystalline polyesterpolyol (B1) having a melting point of from 50°C to 70°C inclusive and the amorphous polyester polyol (B2) having an average functionality of from 2.01 to 2.2 inclusive.
  • the polyester polyol (B1) is crystalline and has ameltingpoint of from 50°C to 70°C inclusive.
  • the phrase "the polyesterpolyol (B1) is crystalline" means that the polyester polyol (B1) has a melting point and its heat of fusion is 0.1 J/g or more. If the melting point is lower than 50°C, sufficient initial cohesion is difficult to obtain. If the melting point exceeds 70°C, Application property may deteriorate.
  • the melting point and the heat of fusion of the polyester polyol (B1) are measured as follows.
  • a differential scanning calorimeter (DSC-7000 manufactured by SII Nano Technology Inc. The calorimeter is hereinafter referred to as the DSC) is used. 5 mg of a sample is heated from 30°C to T 1 °C at 10°C/min in a nitrogen flow of 20 mL/min, held at T 1 °C for 10 minutes, and then cooled to T 2 °C at 10°C/min to erase the thermal history. The sample is held at T 2 °C for 5 minutes and heated again to T 3 °C at 10°C/min to measure a DSC curve. The maximum peak temperature in the endothermic curve observed in the second heating step is used as the melting point, and the heat of fusion is computed from the area surrounded by the maximum peak and the baseline.
  • T 2 is lower than T 3 , and T 3 is equal to or lower than T 1 .
  • T 2 is sufficiently lower than the glass transition temperature of the crystalline polyester polyol (B1) , and T 1 and T 3 are higher by at least 30°C than the melting point of the crystalline polyester polyol (B1) .
  • T 1 is 200°C
  • T 2 is -80°C
  • T 3 is 200°C.
  • T 1 , T 2 , and T 3 are appropriately adjusted depending on the measurement sample.
  • the polyester polyol (B1) is a reaction product of a monomer composition containing a polycarboxylic acid and a polyhydric alcohol.
  • the polycarboxylic acid used for the synthesis of the polyester polyol (B1) include: aliphatic polybasic acids such as oxalic acid, malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, and dimer acids; alkyl esters of aliphatic polybasic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate;
  • alicyclic polybasic acids such as 1, 1-cyclopentanedicarboxylic acid, 1, 2-cyclopentanedicarboxylic acid, 1, 3-cyclopentanedicarboxylic acid, 1, 2-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, cyclohexane-1, 2, 4-tricarboxylic acid-1, 2-anhydride, himic anhydride, and HET anhydride;
  • aromatic polybasic acids such as ortho-phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1, 4-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 2, 3-naphthalenedicarboxylic anhydride, naphthalic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyldicarboxylic acid, 1, 2-bis (phenoxy) ethane-p, p′-dicarboxylic acid, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic dianhydride, 5-sodium sulfoisophthalic acid, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride; and
  • methyl esters of aromatic polybasic acids such as dimethyl terephthalate and dimethyl 2, 6-naphthalenedicarboxylate. Any of these may be used alone or in combination of two or more.
  • At least one polybasic acid selected from the group consisting of adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, ortho-phthalic acid, and phthalic anhydride is used because the crystallinity of the polyester polyol (B1) cab be increased and its initial cohesion can be further improved.
  • the polyhydric alcohol may be a diol or a trihydric or higher hydric polyol.
  • the diol include: aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1, 3-propanediol, 1, 2, 2-trimethyl-l, 3-propanediol, 2, 2-dimethyl-3-isopropyl-1, 3-propanediol, 1, 4-butanediol, 1, 3-butanediol, 3-methyl-1, 3-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 1, 4-bis (hydroxymethyl) cyclohexane, 2, 2, 4-trimethyl-1, 3-pentanediol, and dimer diols;
  • ether glycols such as polyoxyethylene glycol and polyoxypropylene glycol
  • modified polyether diols obtained by ring-opening polymerization of aliphatic diols and various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether;
  • lactone-based polyester polyols obtained by a polycondensation reaction of aliphatic diols and various lactones such as lactide and ⁇ -caprolactone;
  • bisphenols such as bisphenol A and bisphenol F
  • alkylene oxide adducts of bisphenols obtained by adding ethylene oxide, propylene oxide, etc. to bisphenols such as bisphenol A and bisphenol F.
  • trihydric or higher hydric polyol examples include: aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol;
  • modified polyether polyols obtained by ring-opening polymerization of aliphatic polyols and various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether; and
  • lactone-based polyester polyols obtained by a polycondensation reaction of aliphatic polyols with various lactones such as ⁇ -caprolactone.
  • At least one compound selected from the group consisting of ethylene glycol, propanediol, butanediol, neopentyl glycol, hexanediol, octanediol, and decanediol is used because the crystallinity of the polyester polyol (B1) can be increased and its initial cohesion can be further improved.
  • the number average molecular weight of the polyester polyol (B1) is preferably from 500 to 3,000 inclusive.
  • the number average molecular weight (Mn) in the present invention is a value measured by gel permeation chromatography (GPC) under the following conditions.
  • Measurement device HLC-8320GPC manufactured by TOSOH Corporation
  • TSKgel 4000HXL TSKgel 3000HXL
  • TSKgel 2000HXL TSKgel 2000HXL
  • TSKgel 1000HXL manufactured by TOSOH Corporation
  • RI differential refractometer
  • Sample Obtained by filtering a tetrahydrofuran solution with a resin solid content of 0.2%by mass using a microfilter (100 ⁇ L)
  • the polyester polyol (B2) is an amorphous polyester polyol having an average functionality of from 2.01 to 2.2 inclusive.
  • the average functionality of the polyester polyol (B2) is a value obtained by weight-averaging the numbers of functional groups in monomers used to synthesize the polyesterpolyol (B2) . If the average functionality is less than 2.01, heat sealing strength is low. If the average functionality exceeds 2.2, gelation is likely to occur, and the degree of difficulty in production is high.
  • the polyester polyol (B2) is a reaction product of a monomer composition containing a polycarboxylic acid and a polyhydric alcohol, and the monomer composition further contains a trifunctional or higher functional compound reactable with at least one of the polycarboxylic acid and thepolyhydric alcohol.
  • trifunctional or higher functional compound examples include: polycarboxylic acids such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, and trimer acids; polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, polyglycerin, and sorbitol; and esters of trihydric and higher hydric alcohols and monocarboxylic acids such as glycerin fatty acid esters. Any of these may be used alone or in combination of two or more.
  • polycarboxylic acids such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, and trimer acids
  • polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, polyglycerin, and sorbitol
  • the trifunctional or higher functional compound used is preferably a compound having a large number of functional groups (for example, a compound having 5 or more functional groups) such as dipentaerythritol, polyglycerin, or sorbitol because the heat sealing strength is improved.
  • the polycarboxylic acid and the polyhydric alcohol used for the synthesis of the polyester polyol (B2) are the same as those for the polyester polyol (B1) .
  • No particular limitation is imposed on the number average molecular weight of the polyester polyol (B2) , and the number average molecular weight is, for example, from 500 to 5000 inclusive.
  • the amount of the polyester polyol (B1) relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2) is from 15%by mass to 85%by mass inclusive, and the amount of the polyester polyol (B2) relative to the total amount is from 15%by mass to 85%by mass inclusive.
  • the adhesive has a good balance between the initial cohesion and the heat sealing strength.
  • the amount of the polyester polyol (B1) relative to the total amount is preferably from 45%by mass to 85%by mass inclusive, and the amount of the polyester polyol (B2) relative to the total amount is preferably from 15%by mass to 55%by mass inclusive, because the initial cohesion can be further increased.
  • the polyol composition (B) may further contain a polyol (B3) other than the polyester polyol (B1) and the polyester polyol (B2) .
  • the polyol (B3) include: glycols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, and triethylene glycol;
  • trifunctional and tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, and pentaerythritol
  • bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F
  • dimer diols dimer diols
  • polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as any of the above-described glycols and the above-described trifunctional and tetrafunctional alcohols;
  • alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene
  • polyether urethane polyols obtained by increasing the molecular weights of the polyether polyols using the above-described aromatic and aliphatic polyisocyanates;
  • castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil that is a hydrogenated product of castor oil, and 5 to 50 mole alkylene oxide adducts of castor oil;
  • the amount of the polyol (B3) added is 40%by mass or less.
  • the polyisocyanate composition (A) and the polyol composition (B) are mixed and used such that the ratio of the moles [NCO] of the isocyanate groups contained in the polyisocyanate composition to the moles [OH] of the hydroxy groups contained in the polyol composition, [NCO] / [OH] , is in the range of 1.0 to 3.0.
  • the adhesive of the present invention may further contain additional components other than the polyisocyanate composition (A) and the polyol composition (B) .
  • the adhesive may contain a catalyst, an acid group-containing compound, an adhesion promoter, a pigment, a plasticizer, a leveling agent, inorganic particles such as colloidal silica and an alumina sol, polymethyl methacrylate-based fine organic particles, an antifoaming agent, an anti-sagging agent, a wetting and dispersing agent, a viscosity modifier, an ultraviolet absorber, a metal deactivator, a peroxide decomposer, a flame retardant, a reinforcing agent, a plasticizer, a lubricant, an anticorrosive, a fluorescent brightening agent, an inorganic heat ray absorber, a flame protecting agent, an antistatic agent, adehydrator, well-known commonly used thermoplastic elastomers, a tackifier, a phosphoric acid compound,
  • the additives may be prepared separately and mixed with the polyisocyanate composition (A) and the polyol composition (B) immediately before the application of the adhesive.
  • the catalyst may be optionally used in the adhesive of the present invention to facilitate the curing reaction. No particular limitation is imposed on the catalyst so long as it facilitates the urethanation reaction of the polyisocyanate composition (A) and the polyol composition (B) .
  • the catalyst include metal-based catalysts, amine-based catalysts, aliphatic cyclic amide compounds, and titanium chelate complexes.
  • metal-based catalysts examples include metal complex-based catalysts, inorganic metal-based catalysts, and organic metal-based catalysts.
  • metal complex-based catalysts include acetylacetonate salts of metals selected from the group consisting of Fe (iron) , Mn (manganese) , Cu (copper) , Zr (zirconium) , Th (thorium) , Ti (titanium) , A1 (aluminum) , and Co (cobalt) , such as iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, and zirconia acetylacetonate.
  • iron (III) acetylacetonate Fe(acac) 3
  • manganese (II) acetylacetonate Mn (acac) 2
  • the inorganic metal-based catalyst is selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, etc.
  • organic metal-based catalysts examples include: organozinc compounds such as zinc octylate, zinc neodecanoate, and zinc naphthenate; organic tin compounds such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organic nickel compounds such as nickel octylate and nickel naphthenate; organic cobalt compounds such as cobalt octylate and cobalt naphthenate; organic bismuth compounds such as bismuth octylate, bismuth neodecanoate, and bismuth naphthenate; and titanium-based compounds such as tetraisopropyloxytitanate, dibutyltitanium dich
  • amine-based catalysts examples include triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N, N, N′, N′-tetramethylethylenediamine, N, N, N′, N′-tetramethylpropylenediamine, N, N, N′, N", N"-pentamethyldiethylenetriamine, N, N, N′, N", N"-pentamethyl- (3-aminopropyl) ethylenediamine, N, N, N′, N", N"-pentamethyldipropylenetriamine, N, N, N′, N′-tetramethylhexamethylenediamine, bis (2-dimethylaminoethyl) ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethano1, N, N-dimethyl-N′- (2-hydroxyethyl) ethylenediamine, N, N-di
  • Examples of the aliphatic cyclic amide compounds include ⁇ -valerolactam, ⁇ -caprolactam, ⁇ -enantholactam, ⁇ -capryllactam, and ⁇ -propiolactam. Of these, ⁇ -caprolactam is more effective because curing is facilitated.
  • the titanium chelate compound is a compound whose catalytic activity is increased under irradiation with UV rays and is preferably a titanium chelate complex having an aliphatic or aromatic diketone ligand because of its excellent curing facilitating effect.
  • the titanium chelate complex has, in addition to the aliphatic or aromatic diketone ligand, an alcohol ligand having 2 to 10 carbon atoms because the effects of the invention become significant.
  • any of these catalysts may be used alone or in combination of two or more.
  • the amount of the catalyst added is preferably 0.001 to 3 parts by mass and more preferably 0.01 to 2 parts by mass based on 100 parts by mass of the total solids in the polyisocyanate composition (A) and the polyol composition (B) .
  • the acid group-containing compound examples include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, and unsaturated carboxylic acid anhydrides, and any of these may be used alone or in combination or two or more. More specific examples include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly (ethyloctadecanedioic) anhydride, poly (phenylhexadecanedioic) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl himic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohex
  • a compound obtained by modifying any of the above acid anhydrides with glycol may be used.
  • the glycol that can be used for the modification include: alkylene glycols such as ethylene glycol, propylene glycol, andneopentyl glycol; and polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol.
  • alkylene glycols such as ethylene glycol, propylene glycol, andneopentyl glycol
  • polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol.
  • a copolymerized polyether glycol obtained from two or more of the above glycols and/or polyether glycols may also be used.
  • the acid group-containing compound used may be a copolymer of a carboxylic acid having an unsaturated double bond and an aromatic vinyl compound.
  • the carboxylic acid having an unsaturated double bond is, for example, maleic anhydride.
  • the aromatic vinyl compound include styrene, ⁇ -methylstyrene, and divinylbenzene.
  • the amount of the acid group-containing compound added may be appropriately adjusted according to the intended purpose and is, for example, from 0.1%by mass to 10%by mass inclusive based on the mass of the solids in the polyol composition (B) .
  • adhesionpromoter examples include: coupling agents such as silane coupling agents, titanate-based coupling agents, and aluminum-based coupling agents; and epoxy resins.
  • silane coupling agents include: aminosilanes such as ⁇ -aminopropyltriethoxysilane, ⁇ -aminopropyltrimethoxysilane, N- ⁇ (aminoethyl) - ⁇ -aminopropyltrimethoxysilane, N- ⁇ (aminoethyl) - ⁇ -aminopropyltrimethyldimethoxysilane, and N-phenyl- ⁇ -aminopropyltrimethoxysilane; epoxysilanes such as ⁇ - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, ⁇ -glycidoxypropyltrimethoxysilane, and ⁇ -glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris ( ⁇ -methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, and ⁇ -me
  • titanate-based coupling agents examples include tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxytitanium.
  • aluminum-based coupling agents examples include acetoalcoxyaluminum diisopropylate.
  • epoxy resins examples include: various commercial epoxy resins such as Epi-Bis-type epoxy, novolac-type, ⁇ -methylepichloro-type, cyclic oxirane-type, glycidyl ether-type, glycidyl ester-type, polyglycol ether-type, glycol ether-type, epoxidized fatty acid ester-type, polycarboxylic acid ester-type, amino glycidyl-type, and resorcin-type epoxy resins; and compounds such as triglycidyl tris (2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, acrylic glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, phenol glycidyl ether, p-t-
  • pigment examples thereof include organic and inorganic pigments such as extenders, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminous pigments, and pearlescent pigments, and plastic pigments, which are described in Coating Raw Material Handbook, 1970 (ed. by Japan Paint Manufacturers Association) .
  • organic and inorganic pigments such as extenders, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminous pigments, and pearlescent pigments, and plastic pigments, which are described in Coating Raw Material Handbook, 1970 (ed. by Japan Paint Manufacturers Association) .
  • extenders examples include precipitated barium sulfate, gohun, precipitated calcium carbonate, calcium bicarbonate, white limestone, alumina white, silica, hydrous fine silica particles (white carbon) , anhydrous ultrafine silica particles (AEROSIL) , silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and ocher.
  • AEROSIL anhydrous ultrafine silica particles
  • organic pigments include: insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, and Lake Red 4R; soluble azo pigments such as Lake Red C, Carmine 6B, and Bordeaux 10; (copper) phthalocyanine-based pigments such as Phthalocyanine Blue and Phthalocyanine Green; basic dye lakes such as Rhodamine Lake and Methyl Violet Lake; mordant dye-based pigments such as Quinoline Lake and Fast Sky Blue; vat dye-based pigments such as anthraquinone-based pigments, thioindigo-based pigments, and perinone-based pigments; quinacridone-based pigments such as Cinquasia Red B; dioxazine-based pigments such as Dioxazine Violet; condensed azo pigments such as Cromophtal; and aniline black.
  • insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, and Lake Red 4R
  • soluble azo pigments such as Lake Red C, Carmine 6B, and
  • the inorganic pigments include: chromates such as Chrome Yellow, Zinc Chromate, and Molybdate Orange; ferrocyanide compounds such as Iron Blue; metal oxides such as titanium oxide, zinc white, Mapico Yellow, iron oxide, red iron oxide, Chrome Oxide Green, and zirconium oxide; sulfides and selenides such as Cadmium Yellow, Cadmium Red, and mercury sulfide; sulfates such as barium sulfate and lead sulfate; silicates such as calcium silicate and Ultramarine Blue; carbonates such as calcium carbonate and magnesium carbonate; phosphates such as Cobalt Violet and Manganese Violet; metallic powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, and brass powder; flake pigments; flake pigments and mica flake pigments of these metals; metallic pigments and pearlescent pigments such as mica flake pigments coated with metal oxide and micaceous iron oxide pigments; and graphite and carbon black.
  • plastic pigments examples include "GRANDOLL PP-1000" and “PP-2000S” manufactured by DIC Corporation.
  • the pigment used may be appropriately selected according to the intended purpose.
  • An inorganic pigment such as titanium oxide or zinc white is preferably used as a white pigment, and carbon black is preferably used as a black pigment, because of their excellent durability, weather resistance, and designability.
  • the amount of the pigment added is, for example, 1 to 400 parts by mass based on 100 parts by mass of the total solids in the polyisocyanate composition (A) and the polyol composition (B) .
  • the amount added is more preferably 10 to 300 parts by mass because better bondability and blocking resistance are obtained.
  • plasticizer examples include phthalic acid-based plasticizers, aliphatic acid-based plasticizers, aromatic polycarboxylic acid-basedplasticizers, phosphoric acid-based plasticizers, polyol-based plasticizers, epoxy-based plasticizers, polyester-based plasticizers, and carbonate-based plasticizers.
  • phthalic acid-based plasticizers examples include: phthalate-based plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di (2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, dilauryl phthalate, distearyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, octyl decyl phthalate, dimethyl isophthalate, di- (2-ethylhexyl) isophthalate,
  • aliphatic acid-based plasticizers examples include: adipic acid-based plasticizers such as di-n-butyl adipate, di- (2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di (C6-C10 alkyl) adipates, and dibutyl glycol adipate; azelaic acid-based plasticizers such as di-n-hexyl azelate, di- (2-ethylhexyl) azelate, and diisooctyl azelate; sebacic acid-based plasticizers such as di-n-butyl sebacate, di- (2-ethylhexyl) sebacate, and diisononyl sebacate; maleic acid-based plasticizers such as dimethyl maleate, diethyl maleate, di-n-butyl maleate, and di- (2-ethy
  • aromatic polycarboxylic acid-based plasticizers include: trimellitic acid-based plasticizers such as tri-n-hexyl trimellitate, tri- (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, triisononyl trimellitate, tridecyl trimellitate, and triisodecyl trimellitate; and pyromellitic acid-based plasticizers such as tetra (2-ethylhexyl) pyromellitate and tetra-n-octyl pyromellitate.
  • Examples of the phosphoric acid-based plasticizers include triethyl phosphate, tributyl phosphate, tri- (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, cresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris (chloroethyl) phosphate, tris (chloropropyl) phosphate, tris (dichloropropyl) phosphate, and tris (isopropylphenyl) phosphate.
  • polyol-based plasticizers examples include: glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di (2-ethylbutylate) , triethylene glycol di (2-ethylhexoate) , and dibutyl methylene bisthioglycolate; and glycerin-based plasticizers such as glycerol monoacetate, glycerol triacetate, and glycerol tributyrate.
  • glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di (2-ethylbutylate) , triethylene glycol di (2-ethylhexoate) , and dibutyl methylene bisthioglycolate
  • glycerin-based plasticizers such as glycerol monoa
  • epoxy-based plasticizer examples include epoxidized soybean oil, epoxybutyl stearate, epoxyhexahydrophthalic acid di-2-ethylhexyl ester, epoxyhexahydrophthalic acid diisodecyl ester, epoxytriglyceride, epoxidized octyl oleate, and epoxidized decyl oleate.
  • polyester-based plasticizers examples include adipic acid-based polyesters, sebacic acid-based polyesters, and phthalic acid-based polyesters.
  • carbonate-based plasticizers examples include propylene carbonate and ethylene carbonate.
  • plasticizer examples include partially hydrogenated terphenyl, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate and acrylic monomers and oligomers. Any of these plasticizers may be used alone or in combination of two or more.
  • the adhesive of the present invention is used in the form of a solventless adhesive.
  • the "solventless” adhesive is in the following form.
  • the polyisocyanate composition (A) and the polyol composition (B) substantially do not contain organic solvents whose ability to dissolve the above compositions is high.
  • Examples of such a solvent include: esters such as ethyl acetate, butyl acetate, and cellosolve acetate; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; dimethyl sulfoxide; and dimethylsulfoamide.
  • esters such as ethyl acetate, butyl acetate, and cellosolve acetate
  • ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone
  • ethers such as tetrahydrofuran and dioxane
  • aromatic hydrocarbons such as toluene and xy
  • the polyisocyanate composition (A) and the polyol composition (B) substantially do not contain ethyl acetate and methyl ethyl ketone.
  • the adhesive is used for a so-called nonsolvent lamination method including applying the adhesive to a substrate and laminating the resulting substrate onto another substrate without the step of heating the substrates in, for example, an oven to volatilize a solvent.
  • Organic solvents used as rection mediums for production of the components of the polyisocyanate composition (A) and the polyol composition (B) and their raw materials may not be fully removed.
  • the polyisocyanate composition (A) and the polyol composition (B) are regarded as containing substantially no organic solvents.
  • the polyol composition (B) contains a low-molecular weight alcohol
  • the low-molecular weight alcohol reacts with the polyol composition (B) and forms part of a coating, and therefore it is unnecessary to volatilize the low-molecular weight alcohol after application.
  • Such an adhesive is also treated as a solventless adhesive, and the low-molecular weight alcohol is not regarded as an organic solvent.
  • the solventless adhesive must have a viscosity low enough to allow the adhesive to be applied without dilution with an organic solvent. It is preferable that the viscosity is low at low temperature because good low-temperature workability is obtained.
  • the practical range of the viscosity of a mixture of the polyisocyanate composition (A) and the polyol composition (B) at 70°C immediately after mixing is less than 1100 mPa-s (in the present description, the viscosity is avaluemeasuredusing a rotational viscometer having a cone and a plate (1° ⁇ diameter 50 mm) at a shear rate of 100 sec -1 and 70°C ⁇ 1°C) .
  • the adhesive of the present invention has a viscosity in the practical range and is also excellent in initial cohesion.
  • the adhesive when the solventless adhesive is applied to a film, the adhesive is heated to about 40°C to about 100°C. Then the resulting film is laminated onto another film, and the temperature of the laminate is reduced during coiling. In this case, part of the polyester polyol (B1) is crystallized, and the cohesion of the adhesive coating increases. Therefore, while the viscosity of the adhesive is suitable for nonsolvent lamination, the adhesive is excellent in initial cohesion.
  • polyester polyol (B1) If only the polyester polyol (B1) is used as the polyol composition (B) , heat sealing properties deteriorate.
  • a combination of the polyester polyol (B1) and the polyester polyol (B2) at a specific ratio is used to solve the above problem. This may be because of the following reason. If only the polyester polyol (B1) is used, the adhesion of the adhesive to a film is low because the compatibility between the polyester polyol (B1) and the polyisocyanate compound (A1) is low, and the heat sealing strength decreases.
  • the amorphous polyester polyol (B2) is used in combination with the polyester polyol (B1) , the compatibility among the polyisocyanate compound (A1) , the polyester polyol (B1) , and the polyester polyol (B2) and the adhesion to a film are improved, and the crosslinking density of the cured coating of the adhesive increases.
  • the laminate of the present invention is obtained by laminating a first substrate and a second substrate together using the two-part curable adhesive of the present invention and then curing the adhesive.
  • the substrates used are preferably plastic films generally used for laminates.
  • the first substrate include polyethylene terephthalate (hereinafter abbreviated as PET) films, nylon (hereinafter abbreviated as Ny) films, biaxially stretched polypropylene (hereinafter abbreviated as OPP) films, vapor-deposited films obtained by vapor-depositing deposition layers of metals such as aluminum and inorganic oxides such as silica and alumina on the above films, and aluminum foils.
  • the second substrate examples include: sealant films such as cast polypropylene films (hereinafter abbreviated as CPP) and linear low-density polyethylene (hereinafter abbreviated as LLDPE) films; and vapor-deposited sealant films obtained by disposing metal vapor-deposition layers such as aluminum layers on the sealant films.
  • sealant films such as cast polypropylene films (hereinafter abbreviated as CPP) and linear low-density polyethylene (hereinafter abbreviated as LLDPE) films; and vapor-deposited sealant films obtained by disposing metal vapor-deposition layers such as aluminum layers on the sealant films.
  • the substrates used may be paper sheets. Examples of the paper sheets include natural paper sheets and synthetic paper sheets.
  • a printed layer may be optionally provided on the outer or inner side of each of the substrate and paper layers.
  • the printed layers can be formed by applying a printing ink such as a solvent-type ink, a water-soluble type ink, or an active energy ray curable ink using a well-known printing method such as gravure printing, flexography, offset printing, or inkjet printing.
  • a printing ink such as a solvent-type ink, a water-soluble type ink, or an active energy ray curable ink
  • a well-known printing method such as gravure printing, flexography, offset printing, or inkjet printing.
  • the laminate obtained as described above can be industrially used as packaging materials such as soft packaging films and soft packaging materials (packages whose shape changes depending on a product packaged therein) for packaging detergents and pharmaceutical drugs.
  • Specific examples of the application of the laminate include detergents and pharmaceutical drugs such as liquid laundry detergents, liquid kitchen cleaners, liquid bath cleaners, liquid bath soaps, liquid shampoos, and liquid conditioners.
  • the laminate of the present invention is obtained by applying the adhesive of the present invention heated to about 40°C to about 100°C in advance to a film material serving as a substrate using rolls such as gravure rolls and laminating another film onto the above film immediately after the application.
  • aging treatment is performed after the lamination.
  • the aging temperature is preferably from room temperature to 70°C, and the aging time is preferably from 6 to 240 hours.
  • the amount of the adhesive applied is appropriately adjusted and is, for example, from 1 g/m 2 to 5 g/m 2 inclusive and preferably from 1 g/m 2 to 3 g/m 2 inclusive.
  • the packaging material of the present invention is produced by forming the laminate into a bag shape. Specifically, by heat-sealing the laminate, the packaging material is formed.
  • an optional additional layer may be laminated.
  • a substrate layer, apaper layer, an optional sealant layer, a nonwoven fabric sheet, etc. are used together with the laminate. Any well-known method may be used to laminate an additional layer.
  • an adhesive layer is provided between the additional layer and the laminate to laminate the additional layer using a dry lamination method, a thermal lamination method, a heat sealing method, an extrusion lamination method, etc.
  • the structure of the laminate include: a structure including a first plastic film layer/an adhesive layer/a second plastic film layer anda structure which includes a substrate layer/an adhesive layer/a first plastic film layer/an adhesive layer/a second plastic film layer and in which the first plastic film layer serves as a barrier layer, all of which can be preferably used for general packaging materials, lids, and refill packages; a structure including a second plastic film layer/a paper layer/an adhesive layer/a first plastic film layer/an adhesive layer/a second plastic film layer, a structure including a second plastic filmlayer/a paper layer/a polyolefin resin layer/a substrate layer/a first plastic film layer/an adhesive layer/a second plastic film layer, and a structure including a paper layer/a first plastic film layer/an adhesive layer/a sealant layer, all of which can be preferably used for paper containers and paper cups; and a structure including a second plastic film layer/an adhesive layer/a first plastic film layer/an adhesive layer/a second plastic film layer which can be preferably used for tube containers.
  • polyester resin films such as polyethylene terephthalate (PET) , polyethylene naphthalate (PEN) , and polylactic acid (PLA) films; polyolefin resin films such as polypropylene films; polystyrene resin films; polyamide resin films such as nylon 6 and poly-p-xylylene adipamide (MXD6 nylon) films; polycarbonate resin films; polyacrylonitrile resin films; polyimide resin films; laminates thereof (such as nylon 6/MXD6/nylon 6 and nylon 6/ethylene-vinyl alcohol copolymer/nylon 6) and mixtures thereof.
  • films having high mechanical strength and dimensional stability are preferred. In particular, films stretched in two directions are preferably used.
  • first plastic film layer examples include: soft metal foils such as aluminum foils and vapor-deposited layers obtained by vapor deposition of aluminum, silica, or alumina or binary vapor deposition of silica and alumina, all of which are used to impart the barrier function; and organic barrier layers formed of vinylidene chloride-based resins, modified polyvinyl alcohols, ethylene-vinyl alcohol copolymers, MXD nylon, etc.
  • a conventionally known sealant resin can be used for the second plastic film layer.
  • the sealant resin include: polyethylenes such as low-density polyethylenes (LDPE) , linear low-density polyethylenes (LLDPE) , and high-density polyethylenes (HDPE) ; and polyolefin resins such as acid-modified polyethylenes, polypropylenes (PP) , acid-modified polypropylenes, copolymerized polypropylenes, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylate copolymers, ethylene- (meth) acrylic acid copolymers, and ionomers.
  • polyethylenes such as low-density polyethylenes (LDPE) , linear low-density polyethylenes (LLDPE) , and high-density polyethylenes (HDPE)
  • polyolefin resins such as acid-modified polyethylenes, polypropylenes (PP) , acid
  • the thickness of the sealant layer is preferably in the range of 10 to 60 ⁇ m and more preferably in the range of 15 to 40 ⁇ m.
  • Examples of the paper layer include natural paper layers and synthetic paper layers.
  • a printed layer may be optionally provided on the outer or inner side of each of the substrate and paper layers.
  • the “additional layer” may contain well-known additives and stabilizers such as an antistatic agent, an adhesion enhancing coating agent, a plasticizer, a lubricant, and an antioxidant.
  • the surface of the "additional layer” may be subjected to pre-treatment such as corona treatment, plasma treatment, ozone treatment, chemical treatment, or solvent treatment in order to improve adhesion to another material to be laminated to the additional layer.
  • Examples of the form of the packaging material of the present invention include three-sided seal bags, four-sided seal bags, gusset packaging bags, pillow packaging bags, gable top-type closed-end containers, Tetra Classic packages, brick-type packages, tube containers, paper cups, and lid materials.
  • the packaging material of the present invention may be appropriately subjected to treatment for imparting ease of unsealing and may be provided with resealing means.
  • the packaging material of the present invention can be industrially used mainly as packaging materials to be charged with foods, detergents, and pharmaceutical drugs.
  • Specific examples of the application of the packaging material include detergents and pharmaceutical drugs such as liquid laundry detergents, liquid kitchen cleaners, liquid bath cleaners, liquid bath soaps, liquid shampoos, liquid conditioners, and pharmaceutical tablets.
  • a 2 L four-neck glass flask equipped with a mixing impeller, a temperature sensor, a nitrogen gas introduction tube, and a rectifying column was charged with 47.5 parts by mass of 1, 6-hexanediol and 52.5 parts by mass of adipic acid.
  • the mixture was gradually heated to 220°C in a nitrogen gas flow at normal pressure while a dehydration reaction was performed, and the reaction was continued at 220°C.
  • the rectifying column was detached and replaced with a glass-made condenser, and the nitrogen gas introduction tube was connected toa vacuum pump through a line.
  • a condensation reaction was performed at a reduced pressure of 50 Torr until a predetermined acid value was reached, and a polyester polyol (B1-1) was thereby obtained.
  • the average functionality, acid value, hydroxyl value, and melting point of the polyesterpolyol (B1-1) are shown in Table 1.
  • Polyester polyols (B1-2) and (BH1-1) were obtained by the same procedure as in (Synthesis Example 1) except that raw materials shown in Table 1 were used.
  • the average functionality, acid value, hydroxyl value, and melting point of each of the polyester polyols (B1-2) and (BH1-1) are shown in Table 1.
  • a 2 L four-neck glass flask equipped with a mixing impeller, a temperature sensor, a nitrogen gas introduction tube, and a rectifying column was charged with 3.2 parts by mass of ethylene glycol, 9.3 parts by mass of diethylene glycol, 13.6 parts by mass of neopentyl glycol, 9.3 parts by mass of 1, 6-hexanediol, 9.1 parts by mass of trimethylolpropane, 25.2 parts by mass of adipic acid, 26.0 parts by mass of isophthalic acid, and 4.3 parts by mass of sebacic acid.
  • the mixture was gradually heated to 250°C in a nitrogen gas flow at normal pressure while a dehydration reaction was performed, and the reaction was continued at 250°C for 3 hours.
  • the mixture was cooled to 240°C.
  • the rectifying column was detached and replaced with a glass-made condenser, and the nitrogen gas introduction tube was connected to a vacuum pump through a line.
  • a condensation reaction was performed at a reduced pressure of 50 Torr until a predetermined acid value was reached, and a polyester polyol (B2-1) was thereby obtained.
  • the fraction of trifunctional and higher functional glycols in the polyester polyol (B2-1) and the average functionality, acid value, and hydroxyl value of the polyester polyol (B2-1) are shown in Table 2.
  • Polyester polyols (B2-2) to (B2-4) and (BH2-1) were obtained by the same procedure as in (Synthesis Example 3) except that raw materials shown in Table 2 were used.
  • the fraction of trifunctional and higher functional glycols in each of the polyester polyols (B2-2) to (B2-4) and (BH2-1) and the average functionality, acid value, and hydroxyl value of each of the polyester polyols (B2-2) to (B2-4) and (BH2-1) are shown in Table 2.
  • polyester polyol (B1-1) 1.1 Parts of the polyester polyol (B1-1) , 2.5 parts of the polyester polyol (B2-1) , and 2 parts of the polyisocyanate composition (A) were mixed to prepare an adhesive in Example 1.
  • Adhesives in Examples and Comparative Examples were prepared in the same manner except that the polyester polyols (B1) and (B2) used and their amounts added were changed as shown in Tables 3 to 6.
  • the symbols (B1) / (B2) in the tables mean the amount of the polyester polyol (B1) and the amount of the polyester polyol (B2) , respectively, relative to the total amount of the polyester polyols (B1) and (B2) (these are based on %by mass) .
  • the (B1) / (B2) field is left blank.
  • One of the adhesives was applied to a PET film with a thickness of 50 ⁇ m such that the amount applied was 2.0 g/m 2 , and then the surface coated with the adhesive was laminated onto another PET film with a thickness of 50 ⁇ m. Immediately after the lamination, a sample was cut out from the laminate such that the bonding surface had a size of 10 mm x 10 mm and used as an evaluation sample 1.
  • the adhesive was applied toa nylon film with a thickness of 15 ⁇ m such that the amount applied was 2.0 g/m 2 , and then the surface coated with the adhesive was laminated onto a linear low-density polyethylene (LLDPE) film having a thickness of 60 ⁇ m.
  • LLDPE linear low-density polyethylene
  • An Instron tensile tester was used to measure the shear strength of the evaluation sample 1 under the conditions of an atmosphere temperature of 25°C andapeel ratee of 5mm/minute. The results are summarized in Tables 3 to 6. A shear strength of 1 N/100 m 2 or higher is a practically allowable level.
  • Portions of the sealant film surface of the evaluation sample 2 were heat-sealed using a sealing bar with a width of 10 mm under the conditions of 180°C, 10 N/cm 2 , and 1 second.
  • the tensile strength (N/15 mm) between the portions of the sealant film was measured under the conditions of an atmosphere temperature of 25°C, a peel rate of 300 mm/minute, and T type, rated using the following four level rating scale, and summarized in Tables 3 to 6.
  • Example 1 Example 2 Example 3 Example 4 Example 5 Polyester polyol (B1-1) 1.1 0.7 1.1 Polyester polyol (B1-2) 1.1 1.1 Polyester polyol (B2-1) 2.5 Polyester polyol (B2-2) 2.5 Polyester polyol (B2-3) 2.5 Polyester polyol (B2-4) 2.7 2.5 Polyisocyanate composition (A) 2 2 2 2 2 (B1) / (B2) 31/69 31/69 31/69 21/79 31/69 Shear strength (N/100 m 2 ) 1.2 1.3 1.3 1.1 1.2 Heat sealing strength (N/15 mm) A A A A AA AA 70°C composition viscosity (mPa-s) A A A A A A A A A A A A A A A A A A AA AA 70°C composition viscosity (mPa-s) A A A A A A A A A A A A A A A A A A A A A A A AA AA 70°C composition viscosity (mPa-s) A A A A A A A A A
  • Example 6 Example 7
  • Example 8 Polyester polyol (B1-1) 2.1 2.1 4.4 Polyester polyol (B1-2) Polyester polyol (B2-1) Polyester polyol (B2-2) Polyester polyol (B2-3) Polyester polyol (B2-4) 2.1 1.1 1.1 Polyisocyanate composition (A) 2 2 2 (B1) / (B2) 50/50 66/34 80/20 Shear strength (N/100 m 2 ) 1.5 2.7 3.4 Heat sealing strength (N/15 mm) AA A A 70°C composition viscosity (mPa-s) A A A A A A A A 70°C composition viscosity (mPa-s) A A A A A A A A A A
  • the adhesive of the present invention is excellent in the balance between the initial cohesion and the heat sealing strength.
  • Comparative Example 1 in which the polyester polyol (B1) was not contained, in Comparative Examples 2 and 8 in which the amount of the polyester polyol (B1) was small, and in Comparative Examples 6 and 7 in which a crystalline polyester polyol whose melting point was excessively low was used, sufficient initial cohesion was not obtained.
  • Comparative Examples 3 4, and 5 in which a polyester polyol with an average functionality was 2 was also used and in Comparative Example 9 in which the amount of the polyester polyol (B2) was small, sufficient heat sealing strength was not obtained.

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  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Adhesives Or Adhesive Processes (AREA)
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  • Polyurethanes Or Polyureas (AREA)

Abstract

Provided is a solventless adhesive having a high initial cohesion and suitable for nonsolvent lamination. The solventless adhesive is a two-part adhesive containing a polyisocyanate composition (A) and a polyol composition (B). The polyol composition (B) contains a crystalline polyester polyol (Bi) having a melting point of from 50℃ to 70℃ inclusive and an amorphous polyester polyol (B2) having an average functionality of from 2.01 to 2.2 inclusive. The amount of the polyester polyol (Bi) relative to the total amount of the polyester polyol (Bi) and the polyester polyol (B2) is from 15%by mass to 85%by mass inclusive, and the amount of the polyester polyol (B2) relative to the total amount is from 15%by mass to 85%by mass inclusive. Also provided are a laminate and packaging material that are obtained using the two-part adhesive.

Description

ADHESIVE, LAMINATE, AND PACKAGING MATERIAL [Technical Field]
The present invention relates to an adhesive, to a laminate obtained using the adhesive, to a method for producing the laminate, and to a packaging material.
[Background Art]
Laminated films (referred to also as laminate films) used for various packaging materials, labels, etc. are produced by laminating various plastic films, metal foils, paper sheets, etc. to impart designs, functionality, shelf life, convenience, and transportability thereto. In particular, packages produced by forming laminated films into a bag shape are used for food products, medical and pharmaceutical products, detergents, etc.
Conventional laminated films are mainly obtained by a dry lamination method including coating a film with a two-part curable adhesive prepared by dissolving a polyisocyanate compound and a polyol compound in a volatile organic solvent, causing the resulting film to pass through an oven to volatilize the organic solvent, and then laminating another film onto the resulting film. However, in recent years, from the viewpoint of reducing the load on the environment and improving the work environment, attention is given to a two-part curable solventless adhesive containing a polyisocyanate compound and a polyol compound that do not contain a volatile organic solvent (PTL 1 and PTL 2) .
[Citation List]
[Patent Literature]
[PTL 1]
Japanese Unexamined Patent Application Publication No. 2014-159548
[PTL 2]
Japanese Unexamined Patent Application Publication No. 2001-172602
[Summary of Invention]
[Technical Problem]
The polyisocyanate compound and the polyol compound used in the solventless adhesive must have a viscosity low enough to allow the adhesive to be applied without dilution with an organic solvent, unlike those in solvent-type adhesives. Therefore, these polyisocyanate and polyol compounds inevitably have low molecular weights. When the molecular weights of the polyisocyanate and polyol compounds are low, the initial cohesion of the adhesive is low, and problems such as tunnel-like delamination starting from an edge of a laminated film (tunneling) and displacement of bonding surfaces of a rolled laminated film (Winding Deviation) may occur. It is contemplated to increase the molecular weights of the polyisocyanate and polyol compounds to some extent and apply them at high temperature. However, in this case, damage to the films is large.
The present invention has been made in view of the above circumstances, and it is an object to provide a solventless adhesive having high initial cohesion and suitable for non-solvent lamination.
[Solution to Problem]
The present invention relates to a two-part adhesive containing a polyisocyanate composition (A) and a polyol composition (B) , wherein the polyol composition (B) contains a crystalline polyester polyol (B1) having a melting point of from 50℃ to 70℃ inclusive and an amorphous polyester polyol (B2) having an average functionality of from 2.01 to 2.2 inclusive, wherein  the amount of the polyester polyol (B1) relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2) is from 15%by mass to 85%by mass inclusive, and wherein the amount of the polyester polyol (B2) relative to the total amount is from 15%by mass to 85%by mass inclusive. The present invention also relates to a laminate obtained using the two-part adhesive and to a packaging material obtained using the two-part adhesive.
[Advantageous Effects of Invention]
The present invention can provide an adhesive which has high initial cohesion, in which tunneling and telescoping are prevented, and which is suitable for non-solvent lamination.
[Description of Embodiments]
[Adhesive]
The adhesive of the present invention is a two-part adhesive containing a polyisocyanate composition (A) and a polyol composition (B) . The adhesive of the present invention will be described in detail.
[Polyisocyanate composition (A) ]
The polyisocyanate composition (A) used in the adhesive of the present invention contains a polyisocyanate compound (A1) . No particular limitation is imposed on the polyisocyanate compound (A1) , and any well-known polyisocyanate compound can be used. Examples of the polyisocyanate compound (A1) include: aromatic polyisocyanates; araliphatic polyisocyanates; aliphatic polyisocyanates; alicyclicpolyisocyanates; biurets, nurates, adducts, and allophanates of these polyisocyanates; carbodiimide-modified isocyanates; and urethane prepolymers obtained by reacting polyisocyanates with polyols. Any of these may be used alone or in combination of two or more.
Examples of the aromatic polyisocyanates include, but not  limited to, 2, 2′-diphenylmethane diisocyanate, 2, 4′-diphenylmethane diisocyanate, 4, 4′-diphenylmethane diisocyanate, 1, 3-phenylene diisocyanate, 4, 4′-diphenyl diisocyanate, 1, 4-phenylene diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4, 4′-toluidine diisocyanate, 2, 4, 6-triisocyanate toluene, 1, 3, 5-triisocyanate benzene, dianisidine diisocyanate, 4, 4′-diphenyl ether diisocyanate, and 4, 4′, 4"-triphenylmethane triisocyanate.
The araliphatic polyisocyanate means an aliphatic isocyanate having at least one aromatic ring in its molecule, and examples thereof include, but not limited to, m-and p-xylylene diisocyanates and α, α, α′, α′-tetramethylxylylene diisocyanate.
Examples of the aliphatic polyisocyanate include, but not limited to, trimethylene diisocyanate, 1, 2-propylene diisocyanate, tetramethylene diisocyanate, 1, 3-butylene diisocyanate, 2, 3-butylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2, 4, 4-trimethylhexamethylene diisocyanate, and dodecamethylene diisocyanate.
Examples of the alicyclic polyisocyanates include, but not limited to, isophorone diisocyanate, 1, 3-cyclopentane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, methyl-2, 4-cyclohexane diisocyanate, methyl-2, 6-cyclohexane diisocyanate, 4, 4′-methylenebis (cyclohexyl isocyanate) , and 1, 4-bis (isocyanatomethyl) cyclohexane.
Examples of the polyol used for the synthesis of the urethane prepolymer include: alkylene glycols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol,  neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, 1, 4-cyclohexanediol, and 1, 4-cyclohexanedimethanol;
bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F;
dimer diols;
bishydroxyethoxybenzene;
polyalkylene glycols such as diethylene glycol, triethylene glycol, other polyethylene glycols, polypropylene glycols, and polybutylene glycols;
urethane bond-containing polyether polyols obtained by further increasing the molecular weights of the polyalkylene glycols with aromatic or aliphatic polyisocyanates;
polyester polyols obtained by reacting alkylene glycols or polyalkylene glycols with at least one of aliphatic dicarboxylic acids having 2 to 13 carbon atoms such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and tridecanedioic acid and aromatic polycarboxylic acids such as ortho-phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid; and polyester polyols that are reaction products of polyesters obtained by a ring-opening polymerization reaction of cyclic ester compounds such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, and β-methyl-σ-valerolactone with polyhydric alcohol such as glycols, glycerin, trimethylolpropane, and pentaerythritol.
[Polyol composition (B) ]
The polyol composition (B) used in the adhesive of the present invention contains the crystalline polyesterpolyol (B1) having a melting point of from 50℃ to 70℃ inclusive and the amorphous polyester polyol (B2) having an average functionality of from  2.01 to 2.2 inclusive.
[Polyester polyol (B1) ]
The polyester polyol (B1) is crystalline and has ameltingpoint of from 50℃ to 70℃ inclusive. In the present description, the phrase "the polyesterpolyol (B1) is crystalline" means that the polyester polyol (B1) has a melting point and its heat of fusion is 0.1 J/g or more. If the melting point is lower than 50℃, sufficient initial cohesion is difficult to obtain. If the melting point exceeds 70℃, Application property may deteriorate.
The melting point and the heat of fusion of the polyester polyol (B1) are measured as follows.
A differential scanning calorimeter (DSC-7000 manufactured by SII Nano Technology Inc. The calorimeter is hereinafter referred to as the DSC) is used. 5 mg of a sample is heated from 30℃ to T 1℃ at 10℃/min in a nitrogen flow of 20 mL/min, held at T 1℃ for 10 minutes, and then cooled to T 2℃ at 10℃/min to erase the thermal history. The sample is held at T 2℃ for 5 minutes and heated again to T 3℃ at 10℃/min to measure a DSC curve. The maximum peak temperature in the endothermic curve observed in the second heating step is used as the melting point, and the heat of fusion is computed from the area surrounded by the maximum peak and the baseline.
T 2 is lower than T 3, and T 3 is equal to or lower than T 1. T 2 is sufficiently lower than the glass transition temperature of the crystalline polyester polyol (B1) , and T 1 and T 3 are higher by at least 30℃ than the melting point of the crystalline polyester polyol (B1) . For example, T 1 is 200℃, T 2 is -80℃, and T 3 is 200℃. However, T 1, T 2, and T 3 are appropriately adjusted depending on the measurement sample.
The polyester polyol (B1) is a reaction product of a monomer composition containing a polycarboxylic acid and a polyhydric  alcohol. Examples of the polycarboxylic acid used for the synthesis of the polyester polyol (B1) include: aliphatic polybasic acids such as oxalic acid, malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, and dimer acids; alkyl esters of aliphatic polybasic acids such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl pimelate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate;
alicyclic polybasic acids such as 1, 1-cyclopentanedicarboxylic acid, 1, 2-cyclopentanedicarboxylic acid, 1, 3-cyclopentanedicarboxylic acid, 1, 2-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, cyclohexane-1, 2, 4-tricarboxylic acid-1, 2-anhydride, himic anhydride, and HET anhydride;
aromatic polybasic acids such as ortho-phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1, 4-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 2, 3-naphthalenedicarboxylic anhydride, naphthalic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyldicarboxylic acid, 1, 2-bis (phenoxy) ethane-p, p′-dicarboxylic acid, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic dianhydride, 5-sodium sulfoisophthalic acid, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride; and
methyl esters of aromatic polybasic acids such as dimethyl terephthalate and dimethyl 2, 6-naphthalenedicarboxylate. Any of these may be used alone or in combination of two or more.
Preferably, at least one polybasic acid selected from the group consisting of adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, ortho-phthalic acid, and phthalic anhydride is used because the crystallinity of the polyester polyol (B1) cab be increased and its initial cohesion can be further improved.
The polyhydric alcohol may be a diol or a trihydric or higher hydric polyol. Examples of the diol include: aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1, 3-propanediol, 1, 2, 2-trimethyl-l, 3-propanediol, 2, 2-dimethyl-3-isopropyl-1, 3-propanediol, 1, 4-butanediol, 1, 3-butanediol, 3-methyl-1, 3-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 1, 4-bis (hydroxymethyl) cyclohexane, 2, 2, 4-trimethyl-1, 3-pentanediol, and dimer diols;
ether glycols such as polyoxyethylene glycol and polyoxypropylene glycol;
modified polyether diols obtained by ring-opening polymerization of aliphatic diols and various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether;
lactone-based polyester polyols obtained by a polycondensation reaction of aliphatic diols and various lactones such as lactide and ε-caprolactone;
bisphenols such as bisphenol A and bisphenol F; and alkylene oxide adducts of bisphenols obtained by adding ethylene oxide, propylene oxide, etc. to bisphenols such as  bisphenol A and bisphenol F.
Examples of the trihydric or higher hydric polyol include: aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol;
modified polyether polyols obtained by ring-opening polymerization of aliphatic polyols and various cyclic ether bond-containing compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether; and
lactone-based polyester polyols obtained by a polycondensation reaction of aliphatic polyols with various lactones such as ε-caprolactone.
Preferably, at least one compound selected from the group consisting of ethylene glycol, propanediol, butanediol, neopentyl glycol, hexanediol, octanediol, and decanediol is used because the crystallinity of the polyester polyol (B1) can be increased and its initial cohesion can be further improved.
No particular limitation is imposed on the number average molecular weight of the polyester polyol (B1) . For example, the number average molecular weight is preferably from 500 to 3,000 inclusive. The number average molecular weight (Mn) in the present invention is a value measured by gel permeation chromatography (GPC) under the following conditions.
Measurement device: HLC-8320GPC manufactured by TOSOH Corporation
Columns: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, and TSKgel 1000HXL manufactured by TOSOH Corporation
Detector: RI (differential refractometer)
Data processing: Multi station GPC-8020 model II manufactured by TOSOH Corporation
Measurement conditions
Column temperature: 40℃
Solvent: Tetrahydrofuran
Flow rate: 0.35 mL/minute
Standard: Monodispersed polystyrene
Sample: Obtained by filtering a tetrahydrofuran solution with a resin solid content of 0.2%by mass using a microfilter (100 μL)
[Polyester polyol (B2) ]
The polyester polyol (B2) is an amorphous polyester polyol having an average functionality of from 2.01 to 2.2 inclusive. The average functionality of the polyester polyol (B2) is a value obtained by weight-averaging the numbers of functional groups in monomers used to synthesize the polyesterpolyol (B2) . If the average functionality is less than 2.01, heat sealing strength is low. If the average functionality exceeds 2.2, gelation is likely to occur, and the degree of difficulty in production is high.
The polyester polyol (B2) is a reaction product of a monomer composition containing a polycarboxylic acid and a polyhydric alcohol, and the monomer composition further contains a trifunctional or higher functional compound reactable with at least one of the polycarboxylic acid and thepolyhydric alcohol. Examples of the trifunctional or higher functional compound include: polycarboxylic acids such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, and trimer acids; polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, polyglycerin, and sorbitol; and esters of trihydric and higher hydric alcohols and monocarboxylic acids such as glycerin fatty acid esters. Any of these may be used alone or in combination of two or more.
The trifunctional or higher functional compound used is  preferably a compound having a large number of functional groups (for example, a compound having 5 or more functional groups) such as dipentaerythritol, polyglycerin, or sorbitol because the heat sealing strength is improved.
The polycarboxylic acid and the polyhydric alcohol used for the synthesis of the polyester polyol (B2) are the same as those for the polyester polyol (B1) . No particular limitation is imposed on the number average molecular weight of the polyester polyol (B2) , and the number average molecular weight is, for example, from 500 to 5000 inclusive.
In the adhesive of the present invention, the amount of the polyester polyol (B1) relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2) is from 15%by mass to 85%by mass inclusive, and the amount of the polyester polyol (B2) relative to the total amount is from 15%by mass to 85%by mass inclusive. In this case, the adhesive has a good balance between the initial cohesion and the heat sealing strength. The amount of the polyester polyol (B1) relative to the total amount is preferably from 45%by mass to 85%by mass inclusive, and the amount of the polyester polyol (B2) relative to the total amount is preferably from 15%by mass to 55%by mass inclusive, because the initial cohesion can be further increased.
[Additional polyol (B3) ]
The polyol composition (B) may further contain a polyol (B3) other than the polyester polyol (B1) and the polyester polyol (B2) . Examples of the polyol (B3) include: glycols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene,  1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, and triethylene glycol;
trifunctional and tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, and pentaerythritol; bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F; dimer diols;
polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as any of the above-described glycols and the above-described trifunctional and tetrafunctional alcohols;
polyether urethane polyols obtained by increasing the molecular weights of the polyether polyols using the above-described aromatic and aliphatic polyisocyanates;
castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil that is a hydrogenated product of castor oil, and 5 to 50 mole alkylene oxide adducts of castor oil;
various vegetable oils; and
mixtures thereof.
No particular limitation is imposed on the amount of the polyol (B3) added. For example, the amount of the polyol (B3) relative to the total amount of the polyester polyol (B1) , the polyester polyol (B2) , and the polyol (B3) is 40%by mass or less.
Preferably, the polyisocyanate composition (A) and the polyol composition (B) are mixed and used such that the ratio of the moles [NCO] of the isocyanate groups contained in the polyisocyanate composition to the moles [OH] of the hydroxy groups contained in the polyol composition, [NCO] / [OH] , is in the range of 1.0 to 3.0.
[Additional components in adhesive]
The adhesive of the present invention may further contain additional components other than the polyisocyanate composition (A) and the polyol composition (B) . Specifically, the adhesive may contain a catalyst, an acid group-containing compound, an adhesion promoter, a pigment, a plasticizer, a leveling agent, inorganic particles such as colloidal silica and an alumina sol, polymethyl methacrylate-based fine organic particles, an antifoaming agent, an anti-sagging agent, a wetting and dispersing agent, a viscosity modifier, an ultraviolet absorber, a metal deactivator, a peroxide decomposer, a flame retardant, a reinforcing agent, a plasticizer, a lubricant, an anticorrosive, a fluorescent brightening agent, an inorganic heat ray absorber, a flame protecting agent, an antistatic agent, adehydrator, well-known commonly used thermoplastic elastomers, a tackifier, a phosphoric acid compound, a melamine resin, a reactive elastomer, etc. These may be contained in one of the polyisocyanate composition (A) and the polyol composition (B) or in both of them. Alternatively, the additives may be prepared separately and mixed with the polyisocyanate composition (A) and the polyol composition (B) immediately before the application of the adhesive. These components will next be described.
[Catalyst]
The catalyst may be optionally used in the adhesive of the present invention to facilitate the curing reaction. No particular limitation is imposed on the catalyst so long as it facilitates the urethanation reaction of the polyisocyanate composition (A) and the polyol composition (B) . Examples of the catalyst include metal-based catalysts, amine-based catalysts, aliphatic cyclic amide compounds, and titanium chelate complexes.
Examples of the metal-based catalysts include metal complex-based catalysts, inorganic metal-based catalysts, and organic metal-based catalysts. Examples of the metal complex-based catalysts include acetylacetonate salts of metals selected from the group consisting of Fe (iron) , Mn (manganese) , Cu (copper) , Zr (zirconium) , Th (thorium) , Ti (titanium) , A1 (aluminum) , and Co (cobalt) , such as iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, and zirconia acetylacetonate. In terms of toxicity and catalytic activity, iron (III) acetylacetonate (Fe(acac)  3) or manganese (II) acetylacetonate (Mn (acac)  2) is preferred.
The inorganic metal-based catalyst is selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, etc.
Examples of the organic metal-based catalysts include: organozinc compounds such as zinc octylate, zinc neodecanoate, and zinc naphthenate; organic tin compounds such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organic nickel compounds such as nickel octylate and nickel naphthenate; organic cobalt compounds such as cobalt octylate and cobalt naphthenate; organic bismuth compounds such as bismuth octylate, bismuth neodecanoate, and bismuth naphthenate; and titanium-based compounds such as tetraisopropyloxytitanate, dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride.
Examples of the amine-based catalysts include triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N, N, N′, N′-tetramethylethylenediamine, N, N, N′, N′-tetramethylpropylenediamine, N, N, N′, N", N"-pentamethyldiethylenetriamine, N, N, N′, N", N"-pentamethyl- (3-aminopropyl) ethylenediamine,  N, N, N′, N", N"-pentamethyldipropylenetriamine, N, N, N′, N′-tetramethylhexamethylenediamine, bis (2-dimethylaminoethyl) ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethano1, N, N-dimethyl-N′- (2-hydroxyethyl) ethylenediamine, N, N-dimethyl-N′- (2-hydroxyethyl) propanediamine, bis (dimethylaminopropyl) amine, bis (dimethylaminopropyl) isopropanolamine, 3-quinuclidinol, N, N, N′, N′-tetramethylguanidine, 1, 3, 5-tris (N, N-dimethylaminopropyl) hexahydro-S-triazine, 1, 8-diazabicyclo [5.4.0] undecene-7, N-methyl-N′- (2-dimethylaminoethyl) piperazine, N, N′-dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1, 2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N, N-dimethylhexanolamine, N-methyl-N′- (2-hydroxyethyl) piperazine, 1- (2-hydroxyethyl) imidazole, 1- (2-hydroxypropyl) imidazole, 1- (2-hydroxyethyl) -2-methylimidazole, and 1- (2-hydroxypropyl) -2-methylimidazole.
Examples of the aliphatic cyclic amide compounds include δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, and β-propiolactam. Of these, ε-caprolactam is more effective because curing is facilitated.
The titanium chelate compound is a compound whose catalytic activity is increased under irradiation with UV rays and is preferably a titanium chelate complex having an aliphatic or aromatic diketone ligand because of its excellent curing facilitating effect. In the present invention, it is preferable that the titanium chelate complex has, in addition to the aliphatic or aromatic diketone ligand, an alcohol ligand having 2 to 10 carbon atoms because the effects of the invention become significant.
Any of these catalysts may be used alone or in combination of two or more. The amount of the catalyst added is preferably 0.001 to 3 parts by mass and more preferably 0.01 to 2 parts by mass based on 100 parts by mass of the total solids in the polyisocyanate composition (A) and the polyol composition (B) .
[Acid group-containing compound]
Examples of the acid group-containing compound include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, and unsaturated carboxylic acid anhydrides, and any of these may be used alone or in combination or two or more. More specific examples include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly (ethyloctadecanedioic) anhydride, poly (phenylhexadecanedioic) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl himic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexenedicarboxylic anhydride, methylcyclohexenetetracarboxylic anhydride, ethylene glycol bistrimellitate dianhydride, HET anhydride, nadic anhydride, methylnadic anhydride, 5- (2, 5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexane-1, 2-dicarboxylic anhydride, 3, 4-dicarboxy-1, 2, 3, 4-tetrahydro-1-naphthalenesuccinic dianhydride, and 1-methyl-dicarboxy-1, 2, 3, 4-tetrahydro-1-naphthalenesuccinic dianhydride.
A compound obtained by modifying any of the above acid anhydrides with glycol may be used. Examples of the glycol that can be used for the modification include: alkylene glycols such as ethylene glycol, propylene glycol, andneopentyl glycol; and polyether glycols such as polyethylene glycol, polypropylene  glycol, and polytetramethylene ether glycol. A copolymerized polyether glycol obtained from two or more of the above glycols and/or polyether glycols may also be used.
The acid group-containing compound used may be a copolymer of a carboxylic acid having an unsaturated double bond and an aromatic vinyl compound. The carboxylic acid having an unsaturated double bond is, for example, maleic anhydride. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, and divinylbenzene.
The amount of the acid group-containing compound added may be appropriately adjusted according to the intended purpose and is, for example, from 0.1%by mass to 10%by mass inclusive based on the mass of the solids in the polyol composition (B) .
[Adhesion promoter]
Examples of the adhesionpromoter include: coupling agents such as silane coupling agents, titanate-based coupling agents, and aluminum-based coupling agents; and epoxy resins.
Examples of the silane coupling agents include: aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane; and γ-mercaptopropyltrimethoxysilane.
Examples of the titanate-based coupling agents include  tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxytitanium.
Examples of the aluminum-based coupling agents include acetoalcoxyaluminum diisopropylate.
Examples of the epoxy resins include: various commercial epoxy resins such as Epi-Bis-type epoxy, novolac-type, β-methylepichloro-type, cyclic oxirane-type, glycidyl ether-type, glycidyl ester-type, polyglycol ether-type, glycol ether-type, epoxidized fatty acid ester-type, polycarboxylic acid ester-type, amino glycidyl-type, and resorcin-type epoxy resins; and compounds such as triglycidyl tris (2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, acrylic glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, phenol glycidyl ether, p-t-butyl phenyl glycidyl ether, adipic aciddiglycidyl ester, o-phthalic aciddiglycidyl ester, glycidyl methacrylate, and butyl glycidyl ether.
[Pigment]
No particular limitation is imposed on the pigment, and examples thereof include organic and inorganic pigments such as extenders, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminous pigments, and pearlescent pigments, and plastic pigments, which are described in Coating Raw Material Handbook, 1970 (ed. by Japan Paint Manufacturers Association) .
Examples of the extenders include precipitated barium sulfate, gohun, precipitated calcium carbonate, calcium bicarbonate, white limestone, alumina white, silica, hydrous fine silica particles (white carbon) , anhydrous ultrafine silica particles  (AEROSIL) , silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and ocher.
Specific examples of the organic pigments include: insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, and Lake Red 4R; soluble azo pigments such as Lake Red C, Carmine 6B, and Bordeaux 10; (copper) phthalocyanine-based pigments such as Phthalocyanine Blue and Phthalocyanine Green; basic dye lakes such as Rhodamine Lake and Methyl Violet Lake; mordant dye-based pigments such as Quinoline Lake and Fast Sky Blue; vat dye-based pigments such as anthraquinone-based pigments, thioindigo-based pigments, and perinone-based pigments; quinacridone-based pigments such as Cinquasia Red B; dioxazine-based pigments such as Dioxazine Violet; condensed azo pigments such as Cromophtal; and aniline black.
Examples of the inorganic pigments include: chromates such as Chrome Yellow, Zinc Chromate, and Molybdate Orange; ferrocyanide compounds such as Iron Blue; metal oxides such as titanium oxide, zinc white, Mapico Yellow, iron oxide, red iron oxide, Chrome Oxide Green, and zirconium oxide; sulfides and selenides such as Cadmium Yellow, Cadmium Red, and mercury sulfide; sulfates such as barium sulfate and lead sulfate; silicates such as calcium silicate and Ultramarine Blue; carbonates such as calcium carbonate and magnesium carbonate; phosphates such as Cobalt Violet and Manganese Violet; metallic powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, and brass powder; flake pigments; flake pigments and mica flake pigments of these metals; metallic pigments and pearlescent pigments such as mica flake pigments coated with metal oxide and micaceous iron oxide pigments; and graphite and carbon black.
Examples of the plastic pigments include "GRANDOLL PP-1000" and "PP-2000S" manufactured by DIC Corporation.
The pigment used may be appropriately selected according to the intended purpose. An inorganic pigment such as titanium oxide or zinc white is preferably used as a white pigment, and carbon black is preferably used as a black pigment, because of their excellent durability, weather resistance, and designability.
The amount of the pigment added is, for example, 1 to 400 parts by mass based on 100 parts by mass of the total solids in the polyisocyanate composition (A) and the polyol composition (B) . The amount added is more preferably 10 to 300 parts by mass because better bondability and blocking resistance are obtained.
[Plasticizer]
Examples of the plasticizer include phthalic acid-based plasticizers, aliphatic acid-based plasticizers, aromatic polycarboxylic acid-basedplasticizers, phosphoric acid-based plasticizers, polyol-based plasticizers, epoxy-based plasticizers, polyester-based plasticizers, and carbonate-based plasticizers.
Examples of the phthalic acid-based plasticizers include: phthalate-based plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, diheptyl phthalate, di (2-ethylhexyl) phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, dilauryl phthalate, distearyl phthalate, diphenyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, octyl decyl phthalate, dimethyl isophthalate, di- (2-ethylhexyl) isophthalate, and diisooctyl isophthalate; and tetrahydrophthalate-based plasticizers such as di- (2-ethylhexyl) tetrahydrophthalate, di-n-octyl tetrahydrophthalate, and diisodecyl tetrahydrophthalate.
Examples of the aliphatic acid-based plasticizers include: adipic acid-based plasticizers such as di-n-butyl adipate, di- (2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di (C6-C10 alkyl) adipates, and dibutyl glycol adipate; azelaic acid-based plasticizers such as di-n-hexyl azelate, di- (2-ethylhexyl) azelate, and diisooctyl azelate; sebacic acid-based plasticizers such as di-n-butyl sebacate, di- (2-ethylhexyl) sebacate, and diisononyl sebacate; maleic acid-based plasticizers such as dimethyl maleate, diethyl maleate, di-n-butyl maleate, and di- (2-ethylhexyl) maleate; fumaric acid-based plasticizers such as di-n-butyl fumarate and di- (2-ethylhexyl) fumarate; itaconic acid-based plasticizers such as monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, and di- (2-ethylhexyl) itaconate; stearic acid-based plasticizers such as n-butyl stearate, glycerinmonostearate, anddiethylene glycol distearate; oleic acid-based plasticizers such as butyl oleate, glyceryl monooleate, anddiethylene glycol monooleate; citric acid-based plasticizers such as triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, and acetyl tri (2-ethylhexyl) citrate; ricinoleic acid-based plasticizers such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, glyceryl monoricinoleate, and diethylene glycol monoricinoleate; and other aliphatic acid-basedplasticizers such as diethylene glycol monolaurate, diethylene glycol dipelargonate, and pentaerythritol fatty acid esters.
Examples of the aromatic polycarboxylic acid-based plasticizers include: trimellitic acid-based plasticizers such as tri-n-hexyl trimellitate, tri- (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, triisononyl trimellitate, tridecyl trimellitate, and triisodecyl trimellitate; and pyromellitic acid-based plasticizers such as tetra (2-ethylhexyl) pyromellitate and tetra-n-octyl  pyromellitate.
Examples of the phosphoric acid-based plasticizers include triethyl phosphate, tributyl phosphate, tri- (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, cresyl phenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris (chloroethyl) phosphate, tris (chloropropyl) phosphate, tris (dichloropropyl) phosphate, and tris (isopropylphenyl) phosphate.
Examples of the polyol-based plasticizers include: glycol-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di (2-ethylbutylate) , triethylene glycol di (2-ethylhexoate) , and dibutyl methylene bisthioglycolate; and glycerin-based plasticizers such as glycerol monoacetate, glycerol triacetate, and glycerol tributyrate.
Examples of the epoxy-based plasticizer include epoxidized soybean oil, epoxybutyl stearate, epoxyhexahydrophthalic acid di-2-ethylhexyl ester, epoxyhexahydrophthalic acid diisodecyl ester, epoxytriglyceride, epoxidized octyl oleate, and epoxidized decyl oleate.
Examples of the polyester-based plasticizers include adipic acid-based polyesters, sebacic acid-based polyesters, and phthalic acid-based polyesters.
Examples of the carbonate-based plasticizers include propylene carbonate and ethylene carbonate.
Other examples of the plasticizer include partially hydrogenated terphenyl, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate and acrylic monomers and oligomers. Any of these plasticizers may  be used alone or in combination of two or more.
[Form of adhesive]
The adhesive of the present invention is used in the form of a solventless adhesive. In the present description, the "solventless" adhesive is in the following form. The polyisocyanate composition (A) and the polyol composition (B) substantially do not contain organic solvents whose ability to dissolve the above compositions is high. Examples of such a solvent include: esters such as ethyl acetate, butyl acetate, and cellosolve acetate; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; dimethyl sulfoxide; and dimethylsulfoamide. In particular, the polyisocyanate composition (A) and the polyol composition (B) substantially do not contain ethyl acetate and methyl ethyl ketone. The adhesive is used for a so-called nonsolvent lamination method including applying the adhesive to a substrate and laminating the resulting substrate onto another substrate without the step of heating the substrates in, for example, an oven to volatilize a solvent. Organic solvents used as rection mediums for production of the components of the polyisocyanate composition (A) and the polyol composition (B) and their raw materials may not be fully removed. Even when a small amount of such organic solvents remain present in the polyisocyanate composition (A) and the polyol composition (B) , the polyisocyanate composition (A) and the polyol composition (B) are regarded as containing substantially no organic solvents. When the polyol composition (B) contains a low-molecular weight alcohol, the low-molecular weight alcohol reacts with the polyol composition (B) and forms part of a coating, and therefore it is unnecessary to volatilize the low-molecular weight alcohol after application. Such an adhesive is also treated as a solventless adhesive, and the low-molecular weight alcohol is not regarded  as an organic solvent.
Unlike solvent-type adhesives, the solventless adhesive must have a viscosity low enough to allow the adhesive to be applied without dilution with an organic solvent. It is preferable that the viscosity is low at low temperature because good low-temperature workability is obtained. However, for example, the practical range of the viscosity of a mixture of the polyisocyanate composition (A) and the polyol composition (B) at 70℃ immediately after mixing is less than 1100 mPa-s (in the present description, the viscosity is avaluemeasuredusing a rotational viscometer having a cone and a plate (1° × diameter 50 mm) at a shear rate of 100 sec -1 and 70℃±1℃) . The adhesive of the present invention has a viscosity in the practical range and is also excellent in initial cohesion.
As described later, when the solventless adhesive is applied to a film, the adhesive is heated to about 40℃ to about 100℃. Then the resulting film is laminated onto another film, and the temperature of the laminate is reduced during coiling. In this case, part of the polyester polyol (B1) is crystallized, and the cohesion of the adhesive coating increases. Therefore, while the viscosity of the adhesive is suitable for nonsolvent lamination, the adhesive is excellent in initial cohesion.
If only the polyester polyol (B1) is used as the polyol composition (B) , heat sealing properties deteriorate. However, a combination of the polyester polyol (B1) and the polyester polyol (B2) at a specific ratio is used to solve the above problem. This may be because of the following reason. If only the polyester polyol (B1) is used, the adhesion of the adhesive to a film is low because the compatibility between the polyester polyol (B1) and the polyisocyanate compound (A1) is low, and the heat sealing strength decreases. However, when the amorphous polyester polyol (B2) is used in combination with the polyester polyol (B1) , the compatibility among the  polyisocyanate compound (A1) , the polyester polyol (B1) , and the polyester polyol (B2) and the adhesion to a film are improved, and the crosslinking density of the cured coating of the adhesive increases.
[Laminate]
The laminate of the present invention is obtained by laminating a first substrate and a second substrate together using the two-part curable adhesive of the present invention and then curing the adhesive. The substrates used are preferably plastic films generally used for laminates. Examples of the first substrate include polyethylene terephthalate (hereinafter abbreviated as PET) films, nylon (hereinafter abbreviated as Ny) films, biaxially stretched polypropylene (hereinafter abbreviated as OPP) films, vapor-deposited films obtained by vapor-depositing deposition layers of metals such as aluminum and inorganic oxides such as silica and alumina on the above films, and aluminum foils. Examples of the second substrate include: sealant films such as cast polypropylene films (hereinafter abbreviated as CPP) and linear low-density polyethylene (hereinafter abbreviated as LLDPE) films; and vapor-deposited sealant films obtained by disposing metal vapor-deposition layers such as aluminum layers on the sealant films. The substrates used may be paper sheets. Examples of the paper sheets include natural paper sheets and synthetic paper sheets. A printed layer may be optionally provided on the outer or inner side of each of the substrate and paper layers. The printed layers can be formed by applying a printing ink such as a solvent-type ink, a water-soluble type ink, or an active energy ray curable ink using a well-known printing method such as gravure printing, flexography, offset printing, or inkjet printing.
The laminate obtained as described above can be industrially used as packaging materials such as soft packaging films and soft packaging materials (packages whose shape changes  depending on a product packaged therein) for packaging detergents and pharmaceutical drugs. Specific examples of the application of the laminate include detergents and pharmaceutical drugs such as liquid laundry detergents, liquid kitchen cleaners, liquid bath cleaners, liquid bath soaps, liquid shampoos, and liquid conditioners.
The laminate of the present invention is obtained by applying the adhesive of the present invention heated to about 40℃ to about 100℃ in advance to a film material serving as a substrate using rolls such as gravure rolls and laminating another film onto the above film immediately after the application. Preferably, aging treatment is performed after the lamination. The aging temperature is preferably from room temperature to 70℃, and the aging time is preferably from 6 to 240 hours. The amount of the adhesive applied is appropriately adjusted and is, for example, from 1 g/m 2 to 5 g/m 2 inclusive and preferably from 1 g/m 2 to 3 g/m 2 inclusive.
[Packaging material]
The packaging material of the present invention is produced by forming the laminate into a bag shape. Specifically, by heat-sealing the laminate, the packaging material is formed. In consideration of the application of the packaging material, its required performance (easy tearability and hand cuttability) , the stiffness and durability required for the packaging material (such as shock resistance and pinhole resistance) , an optional additional layer may be laminated. Generally, a substrate layer, apaper layer, an optional sealant layer, a nonwoven fabric sheet, etc. are used together with the laminate. Any well-known method may be used to laminate an additional layer. For example, an adhesive layer is provided between the additional layer and the laminate to laminate the additional layer using a dry lamination method, a thermal lamination method, a heat sealing method, an extrusion lamination method, etc.
Specific examples of the structure of the laminate include: a structure including a first plastic film layer/an adhesive layer/a second plastic film layer anda structure which includes a substrate layer/an adhesive layer/a first plastic film layer/an adhesive layer/a second plastic film layer and in which the first plastic film layer serves as a barrier layer, all of which can be preferably used for general packaging materials, lids, and refill packages; a structure including a second plastic film layer/a paper layer/an adhesive layer/a first plastic film layer/an adhesive layer/a second plastic film layer, a structure including a second plastic filmlayer/a paper layer/a polyolefin resin layer/a substrate layer/a first plastic film layer/an adhesive layer/a second plastic film layer, and a structure including a paper layer/a first plastic film layer/an adhesive layer/a sealant layer, all of which can be preferably used for paper containers and paper cups; and a structure including a second plastic film layer/an adhesive layer/a first plastic film layer/an adhesive layer/a second plastic film layer which can be preferably used for tube containers. The laminate may optionally include a printed layer, a topcoat layer, etc.
Examples of the first plastic film layer used include: polyester resin films such as polyethylene terephthalate (PET) , polyethylene naphthalate (PEN) , and polylactic acid (PLA) films; polyolefin resin films such as polypropylene films; polystyrene resin films; polyamide resin films such as nylon 6 and poly-p-xylylene adipamide (MXD6 nylon) films; polycarbonate resin films; polyacrylonitrile resin films; polyimide resin films; laminates thereof (such as nylon 6/MXD6/nylon 6 and nylon 6/ethylene-vinyl alcohol copolymer/nylon 6) and mixtures thereof. Of these, films having high mechanical strength and dimensional stability are preferred. In particular, films stretched in two directions are preferably used.
Other examples of the first plastic film layer that can be used include: soft metal foils such as aluminum foils and vapor-deposited layers obtained by vapor deposition of aluminum, silica, or alumina or binary vapor deposition of silica and alumina, all of which are used to impart the barrier function; and organic barrier layers formed of vinylidene chloride-based resins, modified polyvinyl alcohols, ethylene-vinyl alcohol copolymers, MXD nylon, etc.
A conventionally known sealant resin can be used for the second plastic film layer. Examples of the sealant resin include: polyethylenes such as low-density polyethylenes (LDPE) , linear low-density polyethylenes (LLDPE) , and high-density polyethylenes (HDPE) ; and polyolefin resins such as acid-modified polyethylenes, polypropylenes (PP) , acid-modified polypropylenes, copolymerized polypropylenes, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylate copolymers, ethylene- (meth) acrylic acid copolymers, and ionomers. Of these, polyethylene-based resins are preferred in terms of their low-temperature sealing properties, and polyethylenes are particularly preferred because of their low cost. No particular limitation is imposed on the thickness of the sealant layer. In consideration of formability into a packaging material and its heat sealability, the thickness is preferably in the range of 10 to 60 μm and more preferably in the range of 15 to 40 μm. By providing projections and depressions with a height difference of 5 to 20 μm, slidability can be imparted to the sealing layer, and tearability can be imparted to the packaging material.
Examples of the paper layer include natural paper layers and synthetic paper layers. A printed layer may be optionally provided on the outer or inner side of each of the substrate and paper layers.
The "additional layer" may contain well-known additives and stabilizers such as an antistatic agent, an adhesion enhancing coating agent, a plasticizer, a lubricant, and an antioxidant. The surface of the "additional layer" may be subjected to pre-treatment such as corona treatment, plasma treatment, ozone treatment, chemical treatment, or solvent treatment in order to improve adhesion to another material to be laminated to the additional layer.
Examples of the form of the packaging material of the present invention include three-sided seal bags, four-sided seal bags, gusset packaging bags, pillow packaging bags, gable top-type closed-end containers, Tetra Classic packages, brick-type packages, tube containers, paper cups, and lid materials. The packaging material of the present invention may be appropriately subjected to treatment for imparting ease of unsealing and may be provided with resealing means.
The packaging material of the present invention can be industrially used mainly as packaging materials to be charged with foods, detergents, and pharmaceutical drugs. Specific examples of the application of the packaging material include detergents and pharmaceutical drugs such as liquid laundry detergents, liquid kitchen cleaners, liquid bath cleaners, liquid bath soaps, liquid shampoos, liquid conditioners, and pharmaceutical tablets.
[EXAMPLES]
The present invention will next be described in more detail by way of specific Synthesis Examples and Examples. However, the present invention is not limited to these Examples. In the following Examples, "parts" and "%" are "parts by mass" and "%by mass, " respectively, unless otherwise specified.
[Preparation of polyisocyanate composition (A) ]
A 1: 4 mixture of a nurate of isophorone diisocyanate and a nurate  of hexamethylene diisocyanate was used as the polyisocyanate composition (A) .
[Preparation of polyol composition (B) ]
[ (Synthesis Example 1) Synthesis of polyester polyol (B1-1) ]
A 2 L four-neck glass flask equipped with a mixing impeller, a temperature sensor, a nitrogen gas introduction tube, and a rectifying column was charged with 47.5 parts by mass of 1, 6-hexanediol and 52.5 parts by mass of adipic acid. The mixture was gradually heated to 220℃ in a nitrogen gas flow at normal pressure while a dehydration reaction was performed, and the reaction was continued at 220℃. After the temperature of the top of the rectifying column had reached 80℃ or lower, the rectifying column was detached and replaced with a glass-made condenser, and the nitrogen gas introduction tube was connected toa vacuum pump through a line. A condensation reaction was performed at a reduced pressure of 50 Torr until a predetermined acid value was reached, and a polyester polyol (B1-1) was thereby obtained. The average functionality, acid value, hydroxyl value, and melting point of the polyesterpolyol (B1-1) are shown in Table 1.
[ (Synthesis Example 2) and (Comparative Synthesis Example 1) ]
Polyester polyols (B1-2) and (BH1-1) were obtained by the same procedure as in (Synthesis Example 1) except that raw materials shown in Table 1 were used. The average functionality, acid value, hydroxyl value, and melting point of each of the polyester polyols (B1-2) and (BH1-1) are shown in Table 1.
[Table 1]
Figure PCTCN2021074794-appb-000001
[ (Synthesis Example 3) Synthesis of polyester polyol (B2-1) ]
A 2 L four-neck glass flask equipped with a mixing impeller, a temperature sensor, a nitrogen gas introduction tube, and a rectifying column was charged with 3.2 parts by mass of ethylene glycol, 9.3 parts by mass of diethylene glycol, 13.6 parts by mass of neopentyl glycol, 9.3 parts by mass of 1, 6-hexanediol, 9.1 parts by mass of trimethylolpropane, 25.2 parts by mass of adipic acid, 26.0 parts by mass of isophthalic acid, and 4.3 parts by mass of sebacic acid. The mixture was gradually heated to 250℃ in a nitrogen gas flow at normal pressure while a dehydration reaction was performed, and the reaction was continued at 250℃ for 3 hours. After the temperature of the top of the rectifying column had reached 80℃ or lower, the mixture was cooled to 240℃. The rectifying column was detached and replaced with a glass-made condenser, and the nitrogen gas introduction tube was connected to a vacuum pump through a line. A condensation reaction was performed at a reduced pressure of 50 Torr until a predetermined acid value was reached, and a polyester polyol (B2-1) was thereby obtained. The fraction of trifunctional and higher functional glycols in the polyester polyol (B2-1) and the average functionality, acid value, and hydroxyl value of the polyester polyol (B2-1) are shown in Table 2.
[ (Synthesis Example 4) to (Synthesis Example 6) and (Comparative Synthesis Example 2) ]
Polyester polyols (B2-2) to (B2-4) and (BH2-1) were obtained by the same procedure as in (Synthesis Example 3) except that raw materials shown in Table 2 were used. The fraction of trifunctional and higher functional glycols in each of the polyester polyols (B2-2) to (B2-4) and (BH2-1) and the average functionality, acid value, and hydroxyl value of each of the polyester polyols (B2-2) to (B2-4) and (BH2-1) are shown in Table 2.
[Table 2]
Figure PCTCN2021074794-appb-000002
[Preparation of adhesives]
1.1 Parts of the polyester polyol (B1-1) , 2.5 parts of the polyester polyol (B2-1) , and 2 parts of the polyisocyanate composition (A) were mixed to prepare an adhesive in Example 1. Adhesives in Examples and Comparative Examples were prepared in the same manner except that the polyester polyols (B1) and (B2) used and their amounts added were changed as shown in Tables 3 to 6.
The symbols (B1) / (B2) in the tables mean the amount of the polyester polyol (B1) and the amount of the polyester polyol (B2) , respectively, relative to the total amount of the  polyester polyols (B1) and (B2) (these are based on %by mass) . In each of Comparative Examples 1 to 7, at least one of or both the polyester polyols (B1) and (B2) are not contained, and the (B1) / (B2) field is left blank.
[Production of evaluation samples]
[Evaluation sample 1]
One of the adhesives was applied to a PET film with a thickness of 50 μm such that the amount applied was 2.0 g/m 2, and then the surface coated with the adhesive was laminated onto another PET film with a thickness of 50 μm. Immediately after the lamination, a sample was cut out from the laminate such that the bonding surface had a size of 10 mm x 10 mm and used as an evaluation sample 1.
[Evaluation sample 2)
The adhesive was applied toa nylon film with a thickness of 15 μm such that the amount applied was 2.0 g/m 2, and then the surface coated with the adhesive was laminated onto a linear low-density polyethylene (LLDPE) film having a thickness of 60 μm. The laminate was aged at 40℃ for 3 days and used as an evaluation sample 2.
[Evaluation]
[70℃ composition viscosity]
For each of the Examples and Comparative Examples in which respective adhesives were prepared using compositions shown in Tables 3 to 6, the viscosity of the adhesive immediately after preparation was measured at 70℃ using a rotational viscometer and rated using the following four level rating scale. A viscosity of less than 1100 mPa-s is a practically allowable level.
AA: less than 700 mPa-s
A: 700 mPa-s or more and less than 1100 mPa-s
B: 1100 mPa-s or more and less than 1500 mPa-s
C: 1500 mPa-s or more
[Initial cohesion]
An Instron tensile tester was used to measure the shear strength of the evaluation sample 1 under the conditions of an atmosphere temperature of 25℃ andapeel ratee of 5mm/minute. The results are summarized in Tables 3 to 6. A shear strength of 1 N/100 m 2 or higher is a practically allowable level.
[Heat sealing strength]
Portions of the sealant film surface of the evaluation sample 2 were heat-sealed using a sealing bar with a width of 10 mm under the conditions of 180℃, 10 N/cm 2, and 1 second. The tensile strength (N/15 mm) between the portions of the sealant film was measured under the conditions of an atmosphere temperature of 25℃, a peel rate of 300 mm/minute, and T type, rated using the following four level rating scale, and summarized in Tables 3 to 6.
AA: 55 N/15 mm or more
A: 50 N/15 mm or more and less than 55 N/15 mm
B: 40 N/15 mm or more and less than 50 N/15 mm
C: less than 40 N/15 mm
[Table 3]
  Example 1 Example 2 Example 3 Example 4 Example 5
Polyester polyol (B1-1) 1.1     0.7 1.1
Polyester polyol (B1-2)   1.1 1.1    
Polyester polyol (B2-1) 2.5        
Polyester polyol (B2-2)   2.5      
Polyester polyol (B2-3)     2.5    
Polyester polyol (B2-4)       2.7 2.5
Polyisocyanate composition (A) 2 2 2 2 2
(B1) / (B2) 31/69 31/69 31/69 21/79 31/69
Shear strength (N/100 m 2) 1.2 1.3 1.3 1.1 1.2
Heat sealing strength (N/15 mm) A A A AA AA
70℃ composition viscosity (mPa-s) A A A A A
[Table 4]
  Example 6 Example 7 Example 8
Polyester polyol (B1-1) 2.1 2.1 4.4
Polyester polyol (B1-2)      
Polyester polyol (B2-1)      
Polyester polyol (B2-2)      
Polyester polyol (B2-3)      
Polyester polyol (B2-4) 2.1 1.1 1.1
Polyisocyanate composition (A) 2 2 2
(B1) / (B2) 50/50 66/34 80/20
Shear strength (N/100 m 2) 1.5 2.7 3.4
Heat sealing strength (N/15 mm) AA A A
70℃ composition viscosity (mPa-s) A A A
[Table 5]
Figure PCTCN2021074794-appb-000003
[Table 6]
Figure PCTCN2021074794-appb-000004
As is clear from the Examples, the adhesive of the present invention is excellent in the balance between the initial cohesion and the heat sealing strength. However, in Comparative Example 1 in which the polyester polyol (B1) was not contained, in Comparative Examples 2 and 8 in which the amount of the polyester polyol (B1) was small, and in Comparative Examples 6 and 7 in which a crystalline polyester polyol whose melting point was excessively low was used, sufficient initial cohesion was not obtained. In Comparative Examples 3, 4, and 5 in which a polyester polyol with an average functionality was 2 was also used and in Comparative Example 9 in which the amount of the polyester polyol (B2) was small, sufficient heat sealing strength was not obtained.

Claims (6)

  1. A two-part adhesive comprising a polyisocyanate composition (A) and a polyol composition (B) ,
    wherein the polyol composition (B) contains a crystalline polyester polyol (B1) having a melting point of from 50℃ to 70℃ inclusive and an amorphous polyester polyol (B2) having an average functionality of from 2.01 to 2.2 inclusive,
    wherein the amount of the polyester polyol (B1) relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2) is from 15%by mass to 85%by mass inclusive, and wherein the amount of the polyester polyol (B2) relative to the total amount is from 15%by mass to 85%by mass inclusive.
  2. The two-part adhesive according to Claim 1, wherein the amount of the polyester polyol (B1) relative to the total amount is from 45%by mass to 85%by mass inclusive, and
    wherein the amount of the polyester polyol (B2) relative to the total amount is from 15%by mass to 55%by mass inclusive.
  3. The two-part adhesive according to Claim 1, wherein the polyester polyol (B2) is a reaction product of a monomer composition containing a polycarboxylic acid and a polyhydric alcohol, and
    wherein the monomer composition further contains a pentafunctional or higher functional compound reactable with at least one of the polycarboxylic acid and the polyhydric alcohol.
  4. The two-part adhesive according to Claim 1, wherein the ratio [NCO] / [OH] of the number of moles [NCO] of isocyanate groups contained in the polyisocyanate composition (A) to the number of moles [OH] of hydroxy groups contained in the polyol composition (B) is 1.0 to 3.0.
  5. A laminate comprising a first substrate, a second substrate, and an adhesive layer that bonds the first substrate and the second substrate together,
    wherein the adhesive layer is a cured coating of the two-part adhesive according to any one of Claims 1 to 4.
  6. A packaging material comprising the laminate according to Claim 5.
PCT/CN2021/074794 2021-02-02 2021-02-02 Adhesive, laminate, and packaging material WO2022165621A1 (en)

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