Adhesives, laminates and packaging materials

Abstract

The present application provides a solventless adhesive having high initial cohesive force and suitable for solventless 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 (B1) having a melting point of 50°C or higher to 70°C or lower and an amorphous polyester polyol (B2) having an average functionality of 2.01 or higher to 2.2 or lower. The amount of the polyester polyol (B1) is 15 mass% or more to 85 mass% or less relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2), and the amount of the polyester polyol (B2) is 15 mass% or more to 85 mass% or less relative to the total amount. The present application also provides a laminate and a packaging material obtained using the two-part adhesive.

Description

[Technical Field]

[0001] This invention relates to adhesives, laminates obtained using the adhesive, methods for preparing the laminates, and packaging materials. [Background Technology]

[0002] Laminated films (also known as laminated membranes) used in various packaging materials, labels, etc., are produced by laminating various plastic films, metal foils, papers, etc., to give them design, function, shelf life, convenience, and transportability. In particular, packaging produced by shaping laminated films into bag shapes is used for food, pharmaceutical products, detergents, etc.

[0003] Conventional laminated films are mainly obtained through dry lamination, which involves coating a film with a two-part curable adhesive prepared by dissolving a polyisocyanate compound and a polyol compound in a volatile organic solvent, passing the resulting film through an oven to evaporate the organic solvent, and then laminating another film onto the resulting film. However, in recent years, from the viewpoint of reducing environmental impact and improving the working environment, two-part curable solvent-free adhesives containing polyisocyanate compounds and polyol compounds but free of volatile organic solvents have attracted attention (Patent Document 1 and Patent Document 2).

[0004] [List of Citations]

[0005] [Patent Literature]

[0006] [Patent Document 1]

[0007] Japanese Unexamined Patent Application Publication No. 2014-159548

[0008] [Patent Document 2]

[0009] Japanese Unexamined Patent Application Publication No. 2001-172602 [Summary of the Invention]

[0010] [Technical Issues]

[0011] Unlike the polyisocyanate and polyol compounds in solvent-based adhesives, the polyisocyanate and polyol compounds used in solvent-free adhesives must have sufficiently low viscosity to allow for adhesive application without dilution with organic solvents. Therefore, these polyisocyanate and polyol compounds must have low molecular weights. When the molecular weight of the polyisocyanate and polyol compounds is low, the initial cohesive force of the adhesive is low, and problems such as tunneling delamination starting from the edges of the laminate and winding deviation of the bonded surface of the rolled-up laminate may occur. Increasing the molecular weight of the polyisocyanate and polyol compounds to a certain level and applying them at high temperatures has been considered. However, in this case, the damage to the film is significant.

[0012] The present invention was made in view of the above, and one object is to provide a solvent-free adhesive having high initial cohesive strength and suitable for solvent-free lamination.

[0013] [Solution to the problem]

[0014] This invention relates to a two-part adhesive comprising a polyisocyanate composition (A) and a polyol composition (B), wherein the polyol composition (B) comprises a crystalline polyester polyol (B1) with a melting point of 50°C to 70°C (inclusive) and an amorphous polyester polyol (B2) with an average functionality of 2.01 to 2.2 (inclusive), wherein the amount of polyester polyol (B1) is 15% to 85% by mass (inclusive) relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2), and wherein the amount of polyester polyol (B2) is 15% to 85% by mass (inclusive) relative to the total amount. The invention also relates to a laminate obtained using the two-part adhesive and a packaging material obtained using the two-part adhesive.

[0015] [Beneficial effects of the invention]

[0016] The present invention can provide an adhesive with high initial cohesive strength, wherein tunneling and telescoping are prevented, and the adhesive is suitable for solvent-free lamination. [Detailed Implementation]

[0017] [Adhesive]

[0018] The adhesive of the present invention is a two-part adhesive comprising a polyisocyanate composition (A) and a polyol composition (B). The adhesive of the present invention will be described in detail.

[0019] [Polyisocyanate Composition (A)]

[0020] The polyisocyanate composition (A) used in the adhesive of the present invention contains a polyisocyanate compound (A1). There are no particular limitations on the polyisocyanate compound (A1), and any well-known polyisocyanate compound can be used. Examples of the polyisocyanate compound (A1) include: aromatic polyisocyanates; arylita-polyisocyanates; aliphatic polyisocyanates; alicyclic polyisocyanates; biuret, urate, adduct, and urethane of these polyisocyanates; carbodiimide-modified isocyanates; and urethane prepolymers obtained by reacting a polyisocyanate with a polyol. Any of these can be used alone or in combination of two or more.

[0021] Examples of aromatic polyisocyanates include, but are not limited to: 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,3-phenyl diisocyanate, 4,4'-biphenyl diisocyanate, 1,4-phenyl diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanatotoluene, 1,3,5-triisocyanatobenzene, bianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate.

[0022] Aromatic aliphatic polyisocyanates refer to aliphatic isocyanates having at least one aromatic ring in their molecule, and examples include, but are not limited to, m-xylene diisocyanate and p-xylene diisocyanate, as well as α,α,α',α'-tetramethylxylene diisocyanate.

[0023] Examples of aliphatic polyisocyanates include, but are not limited to: trimethylene diisocyanate, 1,2-propylidene diisocyanate, tetramethylene diisocyanate, 1,3-butylidene diisocyanate, 2,3-butylidene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and dodecamethylene diisocyanate.

[0024] Examples of alicyclic polyisocyanates include, but are 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.

[0025] Examples of polyols used in the synthesis of urethane prepolymers 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, neopentanediol, methylpentanediol, dimethylbutanediol, butyl ethyl propylene glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanediol.

[0026] Bisphenols, such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F;

[0027] Dimer diol;

[0028] Dihydroxyethoxybenzene;

[0029] Polyalkylene glycols, such as diethylene glycol, triethylene glycol, other polyethylene glycols, polypropylene glycol, and polybutanediol;

[0030] Polyether polyols containing urethane bonds are obtained by further increasing the molecular weight of polyalkylene glycols using aromatic or aliphatic polyisocyanates.

[0031] Polyester polyols are obtained by reacting alkylene glycols or polyalkylene glycols with at least one aliphatic dicarboxylic acid (such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, and tridecanoic acid) having 2 to 13 carbon atoms and an aromatic polycarboxylic acid (such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid); and

[0032] Polyester polyols are polyester reaction products obtained by ring-opening polymerization of cyclic ester compounds (such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone and β-methyl-σ-valerolactone) with polyols (such as glycols, glycerol, trimethylolpropane and pentaerythritol).

[0033] [Polyol Composition (B)]

[0034] The polyol composition (B) used in the adhesive of the present invention contains a crystalline polyester polyol (B1) with a melting point of 50°C to 70°C (inclusive) and an amorphous polyester polyol (B2) with an average functionality of 2.01 to 2.2 (inclusive).

[0035] [Polyester Polyol (B1)]

[0036] Polyester polyol (B1) is crystalline and has a melting point of 50°C to 70°C (inclusive). In this specification, the statement "polyester polyol (B1) is crystalline" means that polyester polyol (B1) has a melting point and a heat of fusion of 0.1 J / g or higher. If the melting point is below 50°C, it is difficult to obtain sufficient initial cohesion. If the melting point exceeds 70°C, coatability may deteriorate.

[0037] The melting point and heat of fusion of polyester polyol (B1) are measured as follows.

[0038] A differential scanning calorimeter (DSC-7000, manufactured by SII Nano Technology Inc. This calorimeter is referred to as DSC below) was used. A 5 mg sample was heated from 30 °C to T1 °C at 10 °C / min in a nitrogen flow of 20 mL / min, held at T1 °C for 10 min, and then cooled to T2 °C at 10 °C / min to remove thermal history. The sample was held at T2 °C for 5 min and then heated again to T3 °C at 10 °C / min to measure the DSC curve. The maximum peak temperature in the endothermic curve observed in the second heating step was used as the melting point, and the heat of fusion was calculated from the area enclosed by the maximum peak and the baseline.

[0039] T2 is lower than T3, and T3 is equal to or lower than T1. T2 is sufficiently lower than the glass transition temperature of the crystalline polyester polyol (B1), and T1 and T3 are at least 30°C higher than the melting point of the crystalline polyester polyol (B1). For example, T1 is 200°C, T2 is -80°C, and T3 is 200°C. However, T1, T2, and T3 are appropriately adjusted according to the sample being measured.

[0040] Polyester polyol (B1) is the reaction product of a monomer composition containing a polycarboxylic acid and a polyol. Examples of polycarboxylic acids used in the synthesis of polyester polyol (B1) include aliphatic polyacids such as oxalic acid, malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, and dimer acids.

[0041] Alkyl esters of aliphatic polyacids, such as dimethyl malonate, diethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl heptaate, diethyl sebacate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, and diethyl maleate.

[0042] Alicyclic polyacids, 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, bicycloheptenyl anhydride, and HET anhydride;

[0043] Aromatic polycarboxylic acids, such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic anhydride, naphthalenedicarboxylic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, benzophenone tetracarboxylic acid, benzophenone tetracarboxylic dianhydride, sodium 5-sulfotoluenedicarboxylate, tetrachlorophthalic anhydride, and tetrabromophthalic anhydride; and

[0044] Methyl esters of aromatic polybasic acids, such as dimethyl terephthalate and dimethyl 2,6-naphthalenedicarboxylate. Any of them can be used alone or in combination of two or more.

[0045] Preferably, at least one polyacid selected from the group consisting of adipic acid, sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, phthalic acid and phthalic anhydride is used, because it can increase the crystallinity of the polyester polyol (B1) and further improve its initial cohesion.

[0046] Polyols can be diols or polyols with three or more nucleotides. Examples of diols include: aliphatic diols, such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,2,2-trimethyl-1,3-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, neopentanediol, 1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, 2,2,4-trimethyl-1,3-pentanediol, and dimer diols;

[0047] Ether glycols, such as polyoxyethylene glycol and polyoxypropylene glycol;

[0048] Modified polyether diols are obtained by ring-opening polymerization of aliphatic diols and various compounds containing cyclic ether bonds (such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether and allyl glycidyl ether).

[0049] Lactone-based polyester polyols are obtained through the polycondensation reaction of aliphatic diols and various lactones (such as lactide and ε-caprolactone).

[0050] Bisphenols, such as bisphenol A and bisphenol F; and

[0051] Bisphenol alkyl oxide adducts are obtained by adding ethylene oxide, propylene oxide, etc. to bisphenol (such as bisphenol A and bisphenol F).

[0052] Examples of polyols with three or more components include aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerol, hexanetriol, and pentaerythritol.

[0053] Modified polyether polyols are obtained through ring-opening polymerization of aliphatic polyols and various compounds containing cyclic ether bonds (such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether); and

[0054] Lactone-based polyester polyols are obtained through the polycondensation reaction of aliphatic polyols with various lactones (such as ε-caprolactone).

[0055] Preferably, at least one compound selected from the group consisting of ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol, octyl glycol, and decanediol is used, because it can increase the crystallinity of the polyester polyol (B1) and further improve its initial cohesiveness.

[0056] There are no particular limitations on the number-average molecular weight of the polyester polyol (B1). For example, the number-average molecular weight is preferably 500 to 3,000 (inclusive of endpoints). The number-average molecular weight (Mn) in this invention is a value determined by gel permeation chromatography (GPC) under the following conditions.

[0057] Measuring device: HLC-8320GPC, manufactured by TOSOH Corporation

[0058] Pillars: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, and TSKgel 1000HXL, manufactured by TOSOH Corporation.

[0059] Detector: RI (Differential Refractometer)

[0060] Data processing: Multi-station GPC-8020model II, manufactured by TOSOH Corporation.

[0061] Measurement conditions

[0062] Column temperature: 40℃

[0063] Solvent: Tetrahydrofuran

[0064] Flow rate: 0.35 mL / min

[0065] Standard material: Monodisperse polystyrene

[0066] Sample: 100 μL was obtained by filtering a tetrahydrofuran solution with a resin solids content of 0.2% by mass through a microfilter.

[0067] [Polyester Polyol (B2)]

[0068] Polyester polyol (B2) is an amorphous polyester polyol with an average functionality of 2.01 to 2.2 (inclusive). The average functionality of polyester polyol (B2) is obtained by weight-averaging the number of functional groups in the monomers used to synthesize it. If the average functionality is less than 2.01, the heat-sealing strength is low. If the average functionality exceeds 2.2, gelation may occur, and production becomes more difficult.

[0069] Polyester polyol (B2) is a reaction product of a monomer composition containing a polycarboxylic acid and a polyol, wherein the monomer composition further contains a trifunctional or higher compound capable of reacting with at least one of the polycarboxylic acid and polyol. Examples of trifunctional or higher compounds include: polycarboxylic acids, such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, and trimeric acid; polyols, such as glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol, polyglycerol, and sorbitol; and esters of trifunctional or higher alcohols and monocarboxylic acids, such as glycerol fatty acid esters. Any of these can be used alone or in combination of two or more.

[0070] The compounds used are preferably trifunctional or higher compounds with a large number of functional groups (e.g., compounds with five or more functional groups), such as dipentaerythritol, polyglycerol, or sorbitol, because they improve the heat-sealing strength.

[0071] The polycarboxylic acids and polyols used to synthesize polyester polyol (B2) are the same as those used for polyester polyol (B1). There are no particular limitations on the number-average molecular weight of polyester polyol (B2), and the number-average molecular weight is, for example, 500 to 5000 (including endpoints).

[0072] In the adhesive of the present invention, the amount of polyester polyol (B1) is 15% to 85% by mass relative to the total amount of polyester polyol (B1) and polyester polyol (B2), and the amount of polyester polyol (B2) is 15% to 85% by mass relative to this total amount. In this case, the adhesive has a good balance between initial cohesive strength and heat-sealing strength. The amount of polyester polyol (B1) is preferably 45% to 85% by mass (including endpoints) relative to the total amount, and the amount of polyester polyol (B2) is preferably 15% to 55% by mass (including endpoints) relative to the total amount, because the initial cohesive strength can be further improved.

[0073] [Another polyol (B3)]

[0074] The polyol composition (B) may also contain a polyol (B3) other than polyester polyol (B1) and polyester polyol (B2). Examples of polyols (B3) include: diols, such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentanediol, methylpentanediol, dimethylbutanediol, butyl ethyl propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, dihydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanediol, and triethylene glycol;

[0075] Trifunctional and tetrafunctional aliphatic alcohols, such as glycerol, trimethylolpropane and pentaerythritol;

[0076] Bisphenols, such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F;

[0077] Dimer diol;

[0078] Polyether polyols are obtained by addition polymerization of epoxides (such as ethylene oxide, propylene oxide, butane oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexene) in the presence of a polymerization initiator (such as any one of the above diols and the above trifunctional and tetrafunctional alcohols).

[0079] Polyether urethane polyols are obtained by increasing the molecular weight of polyether polyols using the aforementioned aromatic and aliphatic polyisocyanates.

[0080] Castor oil is a polyol, such as castor oil, dehydrated castor oil, hydrogenated castor oil (which is a hydrogenation product of castor oil), and 5 to 50 moles of castor oil alkyl oxide adducts.

[0081] Various vegetable oils; and

[0082] A mixture of them.

[0083] There are no particular restrictions on the amount of polyol (B3) added. For example, the amount of polyol (B3) relative to the total amount of polyester polyol (B1), polyester polyol (B2) and polyol (B3) is less than 40% by mass.

[0084] Preferably, the polyisocyanate composition (A) and the polyol composition (B) are mixed and used such that the ratio of the number of moles of isocyanate groups [NCO] in the polyisocyanate composition to the number of moles of hydroxyl groups [OH] in the polyol composition [NCO] / [OH] is in the range of 1.0 to 3.0.

[0085] [Other components in the adhesive]

[0086] The adhesive of the present invention may also contain additional components besides the polyisocyanate composition (A) and the polyol composition (B). Specifically, the adhesive may contain catalysts, acid-containing compounds, tackifiers, pigments, plasticizers, leveling agents, inorganic particles such as colloidal silica and alumina sols, fine organic particles based on polymethyl methacrylate, defoamers, anti-sagging agents, wetting and dispersing agents, viscosity modifiers, ultraviolet absorbers, metal deactivators, peroxide decomposers, flame retardants, reinforcing agents, plasticizers, lubricants, corrosion inhibitors, fluorescent whitening agents, inorganic heat radiation absorbers, flame retardants, antistatic agents, dehydrating agents, well-known commonly used thermoplastic elastomers, tackifiers, phosphoric acid compounds, melamine resins, reactive elastomers, etc. These may be included in one of the polyisocyanate composition (A) and the polyol composition (B), or in both of them. Alternatively, the additives can be prepared separately and applied to the adhesive immediately after being mixed with the polyisocyanate composition (A) and the polyol composition (B). These components will be described below.

[0087] [catalyst]

[0088] In the adhesive of the present invention, a catalyst may optionally be used to promote the curing reaction. There are no particular limitations on the catalyst, as long as it promotes the urethanation reaction of the polyisocyanate composition (A) and the polyol composition (B). Examples of catalysts include metal-based catalysts, amine-based catalysts, aliphatic cyclic amide compounds, and titanium chelate complexes.

[0089] Examples of metal-based catalysts include metal complex catalysts, inorganic metal-based catalysts, and organometallic catalysts. Examples of metal complex catalysts include acetylacetone salts of metals selected from the group consisting of: Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), Th (thorium), Ti (titanium), Al (aluminum), and Co (cobalt), such as iron acetylacetone, manganese acetylacetone, copper acetylacetone, and zirconium acetylacetone. Considering toxicity and catalytic activity, iron(III) acetylacetone (Fe(acac)3) or manganese(II) acetylacetone (Mn(acac)2) are preferred.

[0090] Inorganic metal catalysts are selected from Sn, Fe, Mn, Cu, Zr, Th, Ti, Al, Co, etc.

[0091] Examples of organometallic catalysts include: organozinc compounds, such as zinc octanoate, zinc neodecanoate, and zinc naphthenate; organotin compounds, such as stannous diacetate, stannous dioctanoate, stannous dioleate, stannous dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride; organoninickel compounds, such as nickel octanoate and nickel naphthenate; organocobalt compounds, such as cobalt octanoate and cobalt naphthenate; organobismuth compounds, such as bismuth octanoate, bismuth neodecanoate, and bismuth naphthenate; and titanium compounds, such as tetraisopropyloxytitanate, dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride.

[0092] Examples of amine catalysts include: triethylenediamine, 2-methyltriethylenediamine, quinine ring, 2-methylquinine ring, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropanediamine, 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, dimethylaminoethoxyethanol, N,N-dimethyl-N'-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N'-(2-hydroxyethyl)propanediamine, bis(dimethylaminopropyl)amine, bis(di... (Methylaminopropyl)isopropanolamine, 3-quinanol, 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-methylimidazolium, 1,2-dimethylimidazolium, 1-isobutyl-2-methylimidazolium, 1-dimethylaminopropylimidazolium, N,N-dimethylhexanolamine, N-methyl-N'-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)imidazolium, 1-(2-hydroxypropyl)imidazolium, 1-(2-hydroxyethyl)imidazolium, 1-(2-hydroxypropyl)imidazolium, 1-(2-hydroxyethyl)-2-methylimidazolium and 1-(2-hydroxypropyl)-2-methylimidazolium.

[0093] Examples of aliphatic cyclic amide compounds include δ-valeramide, ε-caprolactam, ω-heptanolactam, η-octanolactam, and β-propiolactam. Among them, ε-caprolactam is more effective because it promotes curing.

[0094] Titanium chelate compounds are compounds whose catalytic activity is enhanced under ultraviolet irradiation, and preferably titanium chelate complexes having aliphatic or aromatic diketone ligands due to their excellent curing-promoting effect. In this invention, it is preferred that, in addition to aliphatic or aromatic diketone ligands, the titanium chelate complexes also have alcohol ligands containing 2 to 10 carbon atoms, as the effects of this invention become significant.

[0095] Any of these catalysts may be used alone or in combination of two or more. Based on 100 parts by weight of total solids in the polyisocyanate composition (A) and the polyol composition (B), the amount of catalyst added is preferably 0.001 to 3 parts by weight, and more preferably 0.01 to 2 parts by weight.

[0096] [Compounds containing acid groups]

[0097] Examples of compounds containing acid groups include cyclic aliphatic anhydrides, aromatic anhydrides, and unsaturated carboxylic anhydrides, and any one of them may be used alone or in combination of two or more. More specific examples include: phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, dodecenyl succinic anhydride, polyadipic anhydride, polyazelic anhydride, polysedimentic anhydride, poly(ethyl octadecanoic acid) anhydride, poly(phenyl hexadecanoic acid) anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, hexahydrophthalic anhydride, methyl dicycloheptenyl phthalic anhydride, trialkyl tetrahydrophthalic anhydride, methyl cyclohexene phthalic anhydride, methyl cyclohexene tetracarboxylic anhydride, ethylene glycol dipreptyl phthalate dianhydride, HET anhydride, bridged methylene tetrahydrophthalic anhydride (nadic anhydride), methyl bridged methylene tetrahydrophthalic 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-naphthous succinic anhydride and 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthous succinic anhydride.

[0098] Compounds obtained by modifying any of the above-mentioned acid anhydrides with a diol can be used. Examples of diols that can be used for modification include: alkylene glycols, such as ethylene glycol, propylene glycol, and neopentyl glycol; and polyether glycols, such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Copolyether glycols obtained from the above-mentioned diols and / or polyether glycols can also be used.

[0099] The acidic compound used can be a copolymer of a carboxylic acid with an unsaturated double bond and an aromatic vinyl compound. Examples of carboxylic acids with unsaturated double bonds are maleic anhydride. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, and divinylbenzene.

[0100] The amount of the acid-containing compound added can be adjusted appropriately according to the intended use, and for example, it can be from 0.1% by mass to 10% by mass (including endpoint values) based on the mass of the solids in the polyol composition (B).

[0101] [Adhesive]

[0102] Examples of adhesion promoters include coupling agents, such as silane coupling agents, titanate / ester coupling agents, and aluminum coupling agents; and epoxy resins.

[0103] Examples of 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-methacryloyloxypropyltrimethoxysilane; hexamethyldisilazane; and γ-mercaptopropyltrimethoxysilane.

[0104] Examples of titanate / ester coupling agents include: tetraisopropoxy titanium, tetra-n-butoxy titanium, tetrabutyl titanate dimer, tetrastearyl titanate, acetylacetone titanium, titanium lactate, tetraoctyl glycol titanate, titanium lactate, and tetrastearyloxy titanium.

[0105] Examples of aluminum-based coupling agents include aluminum acetoalcoxyaluminum diisopropylate.

[0106] Examples of epoxy resins include: various commercial epoxy resins, such as epi-bis-type epoxy, phenolic varnish type, β-methylepoxy type, cyclic ethylene oxide type, glycidyl ether type, glycidyl ester type, polyglycol ether type, glycol ether type, epoxidized fatty acid ester type, polycarboxylic acid ester type, aminoglycidyl type, and resorcinol type epoxy resins; and compounds such as: triglycidyl tris(2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, acrylate glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, phenol glycidyl ether, p-tert-butylphenyl glycidyl ether, diglycidyl adipic acid, diglycidyl phthalate, glycidyl methacrylate, and butyl glycidyl ether.

[0107] [pigment]

[0108] There are no particular restrictions on pigments, and examples include organic and inorganic pigments, such as extenders, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metallic powder pigments, luminescent pigments, and pearlescent pigments, as well as plastic pigments, which are described in the Coating Raw Material Handbook, 1970 (compiled by the Japan Paint Manufacturers Association).

[0109] Examples of extender pigments include: precipitated barium sulfate, chalk, precipitated calcium carbonate, calcium bicarbonate, white limestone, alumina, silica, hydrated fine silica particles (white carbon ink), anhydrous ultrafine silica particles (AEROSIL), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and ochre.

[0110] Specific examples of 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 pigments, such as Phthalocyanine Blue and Phthalocyanine Green; basic dye lakes, such as Rhodamine Lake and Methyl Violet Lake; and mordant dye lakes, such as Quinoline Lake and Fast Sky. Blue); vat dyes, such as anthraquinone, thioindigo and perinone pigments; quinacridone pigments, such as Cinquasia Red B; dioxazine pigments, such as Dioxazine Violet; condensed azo pigments, such as Cromophtal; and aniline black.

[0111] Examples of inorganic pigments include: chromates, such as Chrome Yellow, zinc chromate, and Molybdate Orange; ferrous cyanide compounds, such as Iron Blue; metal oxides, such as titanium dioxide, zinc white, Mapico Yellow, iron oxide, iron oxide red, chromium oxide green, and zirconium oxide; sulfides and selenides, such as cadmium yellow, cadmium red, and mercuric 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 of these metals and mica flake pigments; metallic pigments and pearlescent pigments, such as mica flake pigments and mica-like titanium dioxide pigments used for coating metal oxides; and graphite and carbon black.

[0112] Examples of plastic pigments include “GRANDOLL PP-1000” and “PP-2000S” manufactured by DIC Corporation.

[0113] The pigments used can be appropriately selected according to the intended application. Inorganic pigments such as titanium dioxide or zinc white are preferred as white pigments, and carbon black is preferred as black pigments because they have excellent durability, weather resistance and designability.

[0114] Based on 100 parts by weight of the total solids in the polyisocyanate composition (A) and the polyol composition (B), the amount of pigment added is, for example, 1 to 400 parts by weight. More preferably, this amount is 10 to 300 parts by weight, as better adhesion and anti-blocking properties are obtained.

[0115] [Plasticizer]

[0116] Examples of plasticizers include: phthalic acid plasticizers, fatty acid plasticizers, aromatic polycarboxylic acid plasticizers, phosphoric acid plasticizers, polyol plasticizers, epoxy plasticizers, polyester plasticizers, and carbonate plasticizers.

[0117] Examples of phthalic acid-based plasticizers include: phthalate ester plasticizers, 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, and diundecyl phthalate. Dilauryl phthalate, distearate phthalate, diphenyl phthalate, dibenzyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, octyl butyl phthalate, dimethyl isophthalate, di-(2-ethylhexyl) isophthalate and diisooctyl isophthalate; and tetrahydrophthalic acid ester plasticizers, such as di-(2-ethylhexyl) tetrahydrophthalate, di-n-octyl tetrahydrophthalate and diisodecyl tetrahydrophthalate.

[0118] Examples of fatty 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) adipate, and dibutyl glycol adipate; azelaic acid-based plasticizers, such as di-n-hexyl azelaate, di-(2-ethylhexyl) azelaate, and diisooctyl azelaate; 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... Itaconic acid monomethyl ester, itaconic acid monobutyl ester, itaconic acid dimethyl ester, itaconic acid diethyl ester, itaconic acid dibutyl ester, and itaconic acid di-(2-ethylhexyl) ester; stearic acid plasticizers, such as n-butyl stearate, glyceryl monostearate, and diethylene glycol distearate; oleic acid plasticizers, such as butyl oleate, glyceryl monooleate, and diethylene glycol monooleate; citric acid plasticizers, such as triethyl citrate, tri-n-butyl citrate, triethyl acetyl citrate, tributyl acetyl citrate, and tri(2-ethylhexyl) acetyl citrate; ricinoleic acid plasticizers, such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, glyceryl monoricinoleate, and diethylene glycol monoricinoleate; and other fatty acid plasticizers, such as diethylene glycol monolaurate, diethylene glycol dinonanoate, and pentaerythritol fatty acid esters.

[0119] Examples of aromatic polycarboxylic acid plasticizers include: trimellitic acid 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 plasticizers, such as tetra(2-ethylhexyl) pyromellitic acid and tetra-n-octyl pyromellitic acid.

[0120] Examples of phosphoric acid plasticizers include: triethyl phosphate, tributyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, diphenyl octyl phosphate, diphenyl methyl phosphate, phenyl methyl phosphate, tricresyl phosphate, tri(xyl) phosphate, tri(chloroethyl) phosphate, tri(chloropropyl) phosphate, tri(dichloropropyl) phosphate, and tri(isopropylphenyl) phosphate.

[0121] Examples of polyol plasticizers include: diol plasticizers, such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di(2-ethylbutyrate), triethylene glycol di(2-ethylhexanoate), and dibutyl methylene dimercaptoacetate; and glycerol plasticizers, such as glycerol monoacetate, glycerol triacetate, and glycerol tributyrate.

[0122] Examples of epoxy plasticizers include: epoxidized soybean oil, epoxy butyl stearate, 2-ethylhexyl phthalate hexahydrogenated, diisodecyl phthalate hexahydrogenated, triglyceride epoxidized, octyl oleate epoxidized, and decyl oleate epoxidized.

[0123] Examples of polyester plasticizers include adipic acid-based polyesters, sebacic acid-based polyesters, and phthalic acid-based polyesters.

[0124] Examples of carbonate-based plasticizers include propylene carbonate and ethylene carbonate.

[0125] Other examples of plasticizers include partially hydrogenated terphenyls, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate and acrylic monomers and oligomers. Any of these plasticizers can be used alone or in combination of two or more.

[0126] [Form of adhesive]

[0127] The adhesive of the present invention is used in the form of a solvent-free adhesive. In this specification, a "solvent-free" adhesive is defined as follows: The polyisocyanate composition (A) and the polyol composition (B) are substantially free of organic solvents with a high ability to dissolve the compositions described above. Examples of such solvents include: esters, such as ethyl acetate, butyl acetate, and acetic acid solvents; 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 dichloromethane and dichloroethane; dimethyl sulfoxide; and dimethyl sulfonamide. Specifically, the polyisocyanate composition (A) and the polyol composition (B) are substantially free of ethyl acetate and methyl ethyl ketone. The adhesive is used in a so-called solvent-free lamination process, which includes applying the adhesive to a substrate and laminating the resulting substrate onto another substrate without the step of heating the substrate, for example, in an oven to evaporate the solvent. The organic solvents used as reaction media for preparing the polyisocyanate composition (A) and the polyol composition (B) and their raw materials can be partially removed. Even when trace amounts of such organic solvents remain in the polyisocyanate composition (A) and the polyol composition (B), they are considered substantially free of organic solvents. When the polyol composition (B) contains low molecular weight alcohols, the low molecular weight alcohols react with the polyol composition (B) and form part of the coating; therefore, it is not necessary to volatilize the low molecular weight alcohols after coating. Such adhesives are also considered solvent-free adhesives, and the low molecular weight alcohols are not considered organic solvents.

[0128] Unlike solvent-based adhesives, solvent-free adhesives must have sufficiently low viscosity to allow for application without dilution with organic solvents. Preferably, the viscosity is low at low temperatures, as this results in good low-temperature processability. However, for example, a mixture of polyisocyanate composition (A) and polyol composition (B) has a practical viscosity range of less than 1100 mPa⁻² immediately after mixing at 70°C (in this specification, viscosity is measured using a rotational viscometer with a cone and plate (1° × 50 mm diameter) at 100 sec). -1 (The shear rate and the value measured at 70℃±1℃). The adhesive of the present invention has a viscosity within this practical range and also has excellent initial cohesion.

[0129] As described later, when the solvent-free adhesive is applied to the film, the adhesive is heated to approximately 40°C to approximately 100°C. The resulting film is then laminated onto another film, and the temperature of the laminate is reduced during winding. In this case, the polyester polyol (B1) partially crystallizes, and the cohesive strength of the adhesive coating increases. Therefore, the adhesive exhibits excellent initial cohesive strength while maintaining a viscosity suitable for solvent-free lamination.

[0130] If only polyester polyol (B1) is used as the polyol composition (B), the heat-sealing performance deteriorates. However, a combination of polyester polyol (B1) and polyester polyol (B2) in a specific ratio is used to address this problem. This is likely due to the following reasons: If only polyester polyol (B1) is used, the adhesive's adhesion to the film is low because of the low compatibility between polyester polyol (B1) and the polyisocyanate compound (A1), and the heat-sealing strength decreases. However, when amorphous polyester polyol (B2) is used in combination with polyester polyol (B1), the compatibility between the polyisocyanate compound (A1), polyester polyol (B1), and polyester polyol (B2), as well as the adhesion to the film, are improved, and the crosslinking density of the cured coating of the adhesive increases.

[0131] [Laminate]

[0132] 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 substrate used is preferably a plastic film commonly used in laminates. Examples of the first substrate include: polyethylene terephthalate (PET) film, nylon (Ny) film, biaxially oriented polypropylene (OPP) film, vapor-deposited films obtained by vapor-depositing metal (e.g., aluminum) and inorganic oxide (e.g., silica and alumina) layers onto the aforementioned films, and aluminum foil. Examples of the second substrate include: sealing films, such as cast polypropylene (CPP) film and linear low-density polyethylene (LLDPE) film; and vapor-deposited sealing films obtained by providing a metal vapor-deposited layer (e.g., an aluminum layer) on the sealing film. The substrate used can be paper. Examples of paper include natural paper and synthetic paper. A printing layer may optionally be provided on the outer or inner side of each of the substrate layer and the paper layer. The printed layer can be formed by applying printing ink (such as solvent-based ink, water-soluble ink, or active energy ray curable ink) using well-known printing methods (such as gravure printing, flexographic printing, offset printing, or inkjet printing).

[0133] The laminates obtained as described above can be used industrially as packaging materials for detergents and pharmaceuticals, such as flexible packaging films and flexible packaging materials (packaging whose shape changes according to the product packaged therein). Specific examples of applications for laminates include detergents and pharmaceuticals, such as liquid laundry detergents, liquid kitchen cleaners, liquid bathroom cleaners, liquid bath soaps, liquid shampoos, and liquid conditioners.

[0134] The laminate of the present invention is obtained by applying the adhesive of the present invention, preheated to about 40°C to about 100°C, to a film material serving as a substrate using a roller (e.g., a gravure roller), and immediately after application, laminating another film onto the aforementioned film. Preferably, an aging treatment is performed after 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 adhesive applied is appropriately adjusted, and for example, is 1 g / m³. 2 Up to 5g / m 2 (Including endpoint values), and preferably 1 g / m 2 Up to 3g / m 2 (Including endpoint values).

[0135] Packaging materials

[0136] The packaging material of this invention is produced by forming a laminate into a bag shape. Specifically, the packaging material is formed by heat-sealing a laminate. Optional additional layers can be laminated, taking into account the application of the packaging material, its required properties (tearability and manual cutting capability), and the required stiffness and durability of the packaging material (e.g., impact resistance and pinhole resistance). Typically, a base layer, a paper layer, an optional sealing layer, a nonwoven fabric layer, etc., are used in conjunction with the laminate. The additional layers can be laminated using any well-known method. For example, an adhesive layer can be provided between the additional layer and the laminate to laminate the additional layer using dry lamination, hot lamination, extrusion lamination, etc.

[0137] Specific examples of laminate structures include: structures comprising a first plastic film layer / adhesive layer / second plastic film layer; and structures comprising a base layer / adhesive layer / first plastic film layer / adhesive layer / second plastic film layer, wherein the first plastic film layer serves as a barrier layer. Laminates with these structures are all preferably used in general packaging materials, caps, and refill packaging. Structures comprising a second plastic film layer / paper layer / adhesive layer / first plastic film layer / adhesive layer / second plastic film layer; structures comprising a second plastic film layer / paper layer / polyolefin resin layer / base layer / first plastic film layer / adhesive layer / second plastic film layer; and structures comprising a paper layer / first plastic film layer / adhesive layer / sealing layer. Laminates with these structures are all preferably used in paper containers and paper cups. A structure comprising a second plastic film layer / adhesive layer / first plastic film layer / adhesive layer / second plastic film layer is preferably used in tubular containers. The laminate may optionally include a printed layer, a topcoat layer, etc.

[0138] 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-phenylene 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 with high mechanical strength and dimensional stability are preferred. In particular, films stretched in two directions are preferred.

[0139] Other examples of first plastic film layers that can be used include: soft metal foils such as aluminum foil, and vapor-deposited layers obtained by vapor deposition of aluminum, silica or alumina or by binary vapor deposition of silica and alumina, all of which are used to impart barrier function; and organic barrier layers formed from: vinylidene chloride resins, modified polyvinyl alcohol, ethylene-vinyl alcohol copolymers, MXD nylon, etc.

[0140] Commonly known sealant resins can be used for the second plastic film layer. Examples of sealant resins include: polyethylene, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); and polyolefin resins, such as acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, copolymerized polypropylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylate copolymer, ethylene-(meth)acrylate copolymer, and ionomers. Polyethylene-based resins are preferred from the viewpoint of their low-temperature sealing properties, and polyethylene is particularly preferred due to its low cost. There is no particular limitation on the thickness of the sealing layer. Considering the formability and heat-sealing properties of the packaging material, 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 protrusions and recesses with a height difference of 5 to 20 μm, the sealing layer can be imparted with sliding properties, and the packaging material can be imparted with tear resistance.

[0141] Examples of paper layers include natural paper layers and synthetic paper layers. Printing layers may optionally be disposed on the outer or inner sides of both the base layer and the paper layer.

[0142] The “extra layer” can contain well-known additives and stabilizers, such as antistatic agents, adhesion-enhancing coating agents, plasticizers, lubricants, and antioxidants. The surface of the “extra layer” can be pretreated, such as by corona treatment, plasma treatment, ozone treatment, chemical treatment, or solvent treatment, to improve the adhesion of other materials to be laminated to the extra layer.

[0143] Examples of the packaging materials of this invention include: three-side seal bags, four-side seal bags, gusset bags, pillow bags, gable top-type closed-end containers, Tetra Classic packages, brick-type packages, tubular containers, paper cups, and lid materials. The packaging materials of this invention can be suitably treated to impart easy-openability and can be provided with resealing devices.

[0144] The packaging material of this invention can be primarily used industrially as packaging material for food, detergents, and pharmaceuticals. Specific examples of its application include detergents and pharmaceuticals, such as liquid laundry detergents, liquid kitchen cleaners, liquid bathroom cleaners, liquid bath soaps, liquid shampoos, liquid conditioners, and tablets.

[0145] [Example]

[0146] The invention will now be described in more detail through specific synthetic examples and embodiments. However, the invention is not limited to these embodiments. In the following embodiments, unless otherwise specified, “parts” and “%” refer to “parts by mass” and “% by mass”, respectively.

[0147] [Preparation of polyisocyanate composition (A)]

[0148] A 1:4 mixture of isophorone diisocyanate urate and hexamethylene diisocyanate urate is used as the polyisocyanate composition (A).

[0149] [Preparation of polyol composition (B)]

[0150] [(Synthetic Example 1) Synthesis of Polyester Polyol (B1-1)]

[0151] A 2L four-necked glass flask equipped with a mixing impeller, temperature sensor, nitrogen inlet pipe, and distillation column was filled with 47.5 parts by mass of 1,6-hexanediol and 52.5 parts by mass of adipic acid. While the dehydration reaction was underway, the mixture was gradually heated to 220°C under atmospheric pressure in a nitrogen stream, and the reaction continued at 220°C. After the temperature at the top of the distillation column reached below 80°C, the column was removed and replaced with a glass condenser, and the nitrogen inlet pipe was connected to a vacuum pump. The condensation reaction was carried out under a reduced pressure of 50 Torr until a predetermined acid value was reached, thereby yielding polyester polyol (B1-1). The average functionality, acid value, hydroxyl value, and melting point of polyester polyol (B1-1) are shown in Table 1.

[0152] [(Synthetic Example 2) and (Comparative Synthetic Example 1)]

[0153] Except for the raw materials shown in Table 1, polyester polyols (B1-2) and (BH1-1) were obtained by the same procedure as in (Synthesis Example 1). The average functionality, acid value, hydroxyl value and melting point of polyester polyols (B1-2) and (BH1-1) are shown in Table 1.

[0154] [Table 1]

[0155]

[0156] [(Synthetic Example 3) Synthesis of Polyester Polyol (B2-1)]

[0157] A 2L four-necked glass flask equipped with a mixing impeller, temperature sensor, nitrogen inlet, and distillation column was filled 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. While the dehydration reaction was underway, the mixture was gradually heated to 250°C under atmospheric pressure in a nitrogen stream and the reaction was continued at 250°C for 3 hours. After the temperature at the top of the distillation column reached below 80°C, the mixture was cooled to 240°C. The distillation column was removed and replaced with a glass condenser, and the nitrogen inlet was connected to a vacuum pump via a pipeline. The condensation reaction was carried out under a reduced pressure of 50 Torr until the predetermined acid value was reached, thereby yielding polyester polyol (B2-1). The fraction of trifunctional or higher diols in polyester polyol (B2-1), as well as the average functionality, acid value, and hydroxyl value of polyester polyol (B2-1), are shown in Table 2.

[0158] [(Synthetic Examples 4) to (Synthetic Examples 6) and (Comparative Synthetic Example 2)]

[0159] In addition to using the raw materials shown in Table 2, polyester polyols (B2-2) to (B2-4) and (BH2-1) were obtained through the same procedure as in (Synthesis Example 3). The fractions of trifunctional or higher diols of each of the polyester polyols (B2-2) to (B2-4) and (BH2-1), as well as the average functionality, acid value, and hydroxyl value of the polyester polyols (B2-2) to (B2-4) and (BH2-1), are shown in Table 2.

[0160] [Table 2]

[0161]

[0162] [Preparation of Adhesives]

[0163] 1.1 parts of polyester polyol (B1-1), 2.5 parts of polyester polyol (B2-1), and 2 parts of polyisocyanate composition (A) were mixed to prepare the adhesive in Example 1. The adhesives in the Examples and Comparative Examples were prepared in the same manner, except that the polyester polyols (B1) and (B2) used and their amounts were varied as shown in Tables 3 to 6.

[0164] The symbols (B1) / (B2) in the table represent, respectively, the amount of polyester polyol (B1) and the amount of polyester polyol (B2) relative to the total amount of polyester polyol (B1) and (B2) (they are based on mass %). In each of Comparative Examples 1 to 7, at least one or both of polyester polyol (B1) and (B2) are not present, and the (B1) / (B2) area is left blank.

[0165] [Preparation of Evaluation Samples]

[0166] [Sample 1 for evaluation]

[0167] One of the adhesives is applied to a PET film with a thickness of 50 μm, resulting in a coating weight of 2.0 g / m. 2 The adhesive-coated surface was then laminated onto another 50 μm thick PET film. Immediately after lamination, a sample was cut from the laminate to make the bonded surface have a size of 10 mm × 10 mm, and this sample was used as evaluation sample 1.

[0168] [Evaluation Sample 2]

[0169] The adhesive was applied to a nylon film with a thickness of 15 μm, resulting in a coating weight of 2.0 g / m. 2 The adhesive-coated surface was then laminated onto a 60 μm thick linear low-density polyethylene (LLDPE) film. The laminate was aged at 40°C for 3 days and used as evaluation sample 2.

[0170] [evaluate]

[0171] [Viscosity of the composition at 70℃]

[0172] For each of the Examples and Comparative Examples in which the respective adhesives were prepared using the compositions shown in Tables 3 to 6, the viscosity of the adhesive immediately after preparation was measured at 70°C using a rotational viscometer and rated using the following four-level rating scale. Viscosities less than 1100 mPa-s are considered practically acceptable.

[0173] AA: less than 700 mPa-s

[0174] A: Above 700 mPa-s and below 1100 mPa-s

[0175] B: Above 1100 mPa-s and below 1500 mPa-s

[0176] C: Above 1500 mPa-s

[0177] [Initial cohesion]

[0178] The shear strength of sample 1 was measured using an Instron tensile testing machine under ambient temperature of 25°C and a peeling speed of 5 mm / min. The results are summarized in Tables 3 to 6. (1 N / 100 m) 2 The above shear strength represents a practically acceptable level.

[0179] [Heat seal strength]

[0180] At 180℃ and 10N / cm 2 Under conditions of 1 second, several portions of the sealing film surface of the evaluation sample 2 were heat-sealed using a 10 mm wide sealing strip. The tensile strength (N / 15 mm) between the portions of the sealing film was measured under atmospheric temperature of 25°C, peel speed of 300 mm / min, and T-conditions, and rated using the following four-level rating scale, summarized in Tables 3 to 6.

[0181] AA: 55N / 15mm and above

[0182] A: 50N / 15mm or higher but less than 55N / 15mm

[0183] B: 40N / 15mm or higher but less than 50N / 15mm

[0184] C: Less than 40N / 15mm

[0185] [Table 3]

[0186] 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 <![CDATA[Shearing strength (N / 100m 2 )]]> 1.2 1.3 1.3 1.1 1.2 Heat seal strength (N / 15mm) A A A AA AA Viscosity of the composition at 70℃ (mPa-s) A A A A A

[0187] [Table 4]

[0188] 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 <![CDATA[Shear strength (N / 100m 2 )]]> 1.5 2.7 3.4 Heat seal strength (N / 15mm) AA A A Viscosity of the composition at 70℃ (mPa-s) A A A

[0189] [Table 5]

[0190]

[0191] [Table 6]

[0192] Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Polyester polyol (B1-1) 0.3 5.6 Polyester polyol (B1-2) Polyester polyol (B2-4) 2.9 0.6 Polyester polyol (BH1-1) 0.7 1.4 Polyester polyol (BH2-1) 2.6 2.1 Polyisocyanate composition (A) 2 2 2 2 (B1) / (B2) 9 / 91 90 / 10 <![CDATA[Shearing strength (N / m 2 )]]> 0.1 0.2 0.4 >5 Heat seal strength (N / 15mm) AA AA AA C Viscosity of the composition at 70℃ (mPa-s) AA AA A A

[0193] As can be seen from the examples, the adhesive of the present invention exhibits excellent balance between initial cohesive strength and heat-sealing strength. However, in Comparative Example 1, which does not contain polyester polyol (B1), in Comparative Examples 2 and 8, which contain a small amount of polyester polyol (B1), and in Comparative Examples 6 and 7, which use crystalline polyester polyols with excessively low melting points, sufficient initial cohesive strength was not obtained. In Comparative Examples 3, 4, and 5, which also use polyester polyols with an average functionality of 2, and in Comparative Example 9, which contains a small amount of polyester polyol (B2), sufficient heat-sealing strength was not obtained.

Claims

1. A two-part adhesive comprising a polyisocyanate composition (A) and a polyol composition (B), The polyol composition (B) contains a crystalline polyester polyol (B1) with a melting point of 50°C to 70°C and an amorphous polyester polyol (B2) with an average functionality of 2.091 to 2.

2. The amount of the polyester polyol (B1) is between 15% by mass and 85% by mass relative to the total amount of the polyester polyol (B1) and the polyester polyol (B2), and The amount of the polyester polyol (B2) is between 15% by mass and 85% by mass relative to the total amount, and The mixture of the polyisocyanate composition (A) and the polyol composition (B) has a viscosity of less than 1100 mPa·s immediately after mixing at 70°C, wherein the viscosity is measured using a rotational viscometer with a cone and a plate at 100 sec. -1 The shear rate and the values ​​measured at 70°C ± 1°C.

2. The two-part adhesive according to claim 1, wherein the amount of said polyester polyol (B1) is 45% by mass or more and 85% by mass or less relative to the total amount, and The amount of the polyester polyol (B2) is between 15% by mass and less than 55% by mass relative to the total amount.

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 polyol, and The monomer composition further comprises a compound with five or more functions capable of reacting with at least one of the polycarboxylic acids and the polyols.

4. The two-part adhesive according to claim 1, wherein the ratio of the molar number of isocyanate groups [NCO] in the polyisocyanate composition (A) to the molar number of hydroxyl groups [OH] in the polyol composition (B) [NCO] / [OH] is 1.0 to 3.

0.

5. A laminate comprising a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate together. The adhesive layer thereon is a cured coating of a two-part adhesive according to any one of claims 1 to 4.

6. A packaging material comprising the laminate according to claim 5.

Images