Polyurethane resin with good substrate adhesion and adhesive composition using same

Abstract

To provide a polyurethane resin that has excellent heat resistance and satisfactory adhesion to various substrates, and an adhesive composition including the resin.SOLUTION: Disclosed herein is a polyurethane resin containing, as copolymerization components, a polycarbonate polyol (A), an organic diisocyanate (B) and a chain extender (C), wherein the polycarbonate polyol (A) contains a specific structure in an amount of 60 mol% or more, the polyurethane resin has a glass transition temperature of 50°C or higher, and the chain extender (C) is neopentyl glycol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyurethane resin that uses a polycarbonate diol having a specific skeleton and an organic diisocyanate and that has good adhesion to various substrates, and to an adhesive composition that uses the resin. [Background technology]

[0002] Conventionally, polyurethane resins have been widely used as adhesives for substrates such as polyethylene terephthalate films and polycarbonate films because they can be designed to have a wide range of physical properties, shapes, and curing patterns, and also have excellent chemical properties such as chemical resistance (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-245312 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the above adhesives contain a large amount of linear aliphatic skeletons in their constituent components, which makes the coating film flexible and improves reactivity, this flexibility poses the problem of loss of adhesion due to flow or decomposition caused by heat load, hot water treatment, etc. Furthermore, the substrates on which they exhibit adhesion are limited, making substrate selectivity an issue.

[0005] The present invention has been made to solve the problems of the prior art. Specifically, the present invention relates to a polyurethane resin that has excellent heat resistance and good adhesion to various substrates, and an adhesive composition that uses the resin. [Means for solving the problem]

[0006] The present inventors have conducted extensive research into the above factors and have found that an adhesive composition using a polyurethane resin whose main raw material is a polycarbonate diol having a specific skeleton has excellent adhesion to various substrates and heat resistance, leading to the completion of the present invention.

[0007] A polyurethane resin containing, as copolymerization components, a polycarbonate polyol (A), an organic diisocyanate (B), and a chain extender (C), wherein the polycarbonate polyol (A) contains 60 mol % or more of a structure represented by the following general formula (1), and the polyurethane resin has a glass transition temperature of 50°C or higher. [ka] (In general formula (1), n ​​represents an integer of 1 to 20.)

[0008] The organic diisocyanate (B) is preferably isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate or hexamethylene diisocyanate, and the chain extender (C) is preferably a glycol compound having 7 or less carbon atoms.

[0009] An adhesive composition comprising the polyurethane resin and a crosslinking agent. [Effects of the Invention]

[0010] The polyurethane resin and adhesive composition of the present invention have excellent adhesion to various substrates and are also excellent in heat resistance and flowability, making them suitable as binders for screen inks and decorative molding. DETAILED DESCRIPTION OF THE INVENTION

[0011] The polyurethane resin of the present invention contains, as copolymerization components, a polycarbonate polyol (A), an organic diisocyanate (B), and a chain extender (C).

[0012] <Polycarbonate polyol (A)> The polycarbonate polyol (A) used in the present invention must contain a structure represented by the following general formula (1). When the entire polycarbonate polyol (A) is taken as 100 mol%, the content of the structure represented by general formula (1) must be 60 mol% or more, preferably 70 mol% or more, more preferably 75 mol% or more, even more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 95 mol% or more, and may even be 100 mol%. The inclusion of the structure represented by general formula (1) imparts flexibility to the polyurethane resin, enabling it to exhibit excellent adhesiveness and heat resistance. [ka]

[0013] In general formula (1), n ​​represents an integer of 1 to 20. Preferably, n is 2 or greater, more preferably 3 or greater, and even more preferably 5 or greater. Furthermore, n is preferably 18 or less, more preferably 15 or less, and even more preferably 10 or less. Within the above ranges, the cohesive strength of the resulting polyurethane resin is improved, and excellent adhesiveness and heat resistance can be achieved.

[0014] As the polycarbonate polyol (A) other than the polycarbonate polyol having the structure represented by general formula (1), an aliphatic polycarbonate polyol, an alicyclic polycarbonate, or an aromatic polycarbonate polyol can be used. When the entire polycarbonate polyol (A) is taken as 100 mol%, these polycarbonate polyols preferably account for 40 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, still more preferably 10 mol% or less, particularly preferably 5 mol% or less, and may even be 0 mol%.

[0015] The aliphatic polycarbonate polyol is not particularly limited, and polycarbonate diols obtained by reacting linear or branched aliphatic glycols such as butanediol, pentanediol, hexanediol, polycaprolactone, polytetramethylene glycol, propylene glycol, and neopentyl glycol with carbonate diesters can be used. The alicyclic polycarbonate polyol is not particularly limited, and polycarbonate diols obtained by reacting alicyclic glycols such as isosorbide with carbonate diesters can be used. The aromatic polycarbonate diol is not particularly limited, and polycarbonate diols obtained by reacting aromatic glycols such as benzenedimethanol and naphthalenedimethanol with carbonate diesters can be used. Polycarbonate diols made from one or a combination of two or more of the above glycols can be used as raw materials.

[0016] The number average molecular weight of the polycarbonate polyol (A) is preferably 300 to 2,500, more preferably 500 to 1,500. By making the number average molecular weight equal to or greater than the lower limit, the cohesive strength of the resulting polyurethane resin is improved, and excellent adhesive properties and heat resistance can be achieved. On the other hand, by making the number average molecular weight equal to or less than the upper limit, an appropriate number of urethane bonds can be ensured, and excellent adhesive properties and heat resistance can be achieved. The number average molecular weight of the polycarbonate diol (A) was calculated by the following formula. Number average molecular weight = (56.1 x 1000 x valence) / hydroxyl value [mgKOH / g] In the above formula, the valence is the number of hydroxyl groups in one molecule, and [mgKOH / g] is the unit of the hydroxyl value.

[0017] <Organic diisocyanate (B)> The organic diisocyanate (B) used in the present invention includes aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), 2-methyl-1,5-pentane diisocyanate, decamethylene diisocyanate, 3-methyl-1,5-pentane diisocyanate, and lysine diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate (IPDI), hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tetramethylxylylene diisocyanate, and cyclohexyl diisocyanate; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), and 2,4'-diphenylmethane diisocyanate. Examples of the aromatic diisocyanates include 2,2'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, o-phenylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethylxylylene diisocyanate, 4,4'-diphenylether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, and 3,3'-dimethoxydiphenyl-4,4'-diisocyanate. Other examples include mixtures containing two or more of the organic diisocyanates, and urethane-modified, allophanate-modified, urea-modified, biuret-modified, uretdione-modified, uretoimine-modified, isocyanurate-modified, and carbodiimide-modified versions of these organic diisocyanates. Preferred organic diisocyanates in the present invention are hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-diphenylmethane diisocyanate, with isophorone diisocyanate being particularly preferred because the resulting polyurethane resin has good solvent solubility, there is little risk of gelation during production, and the resin has excellent weather resistance and mechanical strength.

[0018] The copolymerization amount of the organic diisocyanate (B) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more, per 100 parts by mass of the polycarbonate polyol (A). It is also preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 45 parts by mass or less, and particularly preferably 40 parts by mass or less. By adjusting the amount within the above range, a polyurethane resin with excellent adhesiveness and heat resistance can be obtained.

[0019] <Chain extender (C)> The chain extender (C) used in the present invention is not particularly limited as long as it extends the molecular chain of the polyurethane resin, and preferably has a group reactive with the organic diisocyanate (B). The chain extender (C) is not particularly limited, but from the viewpoint of gelation during production and reactivity, a polyol compound is preferred, and a glycol compound is more preferred. The glycol compound may be any of an aliphatic glycol compound, an aromatic glycol compound, or an alicyclic glycol compound, but an aliphatic glycol compound is preferred. Among these, a linear or branched aliphatic glycol compound having 10 or less carbon atoms is preferred, and a linear or branched aliphatic glycol compound having 7 or less carbon atoms is more preferred. Although the lower limit is not particularly limited, a linear or branched aliphatic glycol compound having 2 or more carbon atoms is preferred, and a linear or branched aliphatic glycol compound having 3 or more carbon atoms is more preferred. Specific examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-ethyl-4-butyl-1,3-propanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, etc. In the present invention, neopentyl glycol or 1,6-hexanediol is preferred from the viewpoints of reactivity and heat resistance.

[0020] The copolymerization amount of the chain extender (C) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and particularly preferably 4 parts by mass or more, per 100 parts by mass of the polycarbonate polyol (A). It is also preferably 20 parts by mass or less, more preferably 15 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 8 parts by mass or less. By adjusting the amount within the above range, a polyurethane resin with excellent adhesiveness and heat resistance can be obtained.

[0021] <Polyurethane resin> The glass transition temperature of the polyurethane resin of the present invention must be 50°C or higher. It is preferably 55°C or higher, and more preferably 60°C or higher. By making the temperature equal to or higher than the lower limit, it is possible to suppress a decrease in adhesion to the substrate due to thermal load and to prevent the occurrence of outflow. It is also preferable that the temperature is 120°C or lower. It is more preferably 110°C or lower, even more preferably 100°C or lower, and particularly preferably 95°C or lower. By making the temperature equal to or lower than the upper limit, it is possible to suppress a decrease in adhesion to the substrate.

[0022] The number-average molecular weight of the polyurethane resin of the present invention is preferably 5,000 to 50,000, more preferably 8,000 to 30,000, and even more preferably 12,000 to 22,000. By setting the number-average molecular weight at or above the lower limit, it is possible to suppress a decrease in adhesiveness due to a decrease in the cohesive strength of the polyurethane resin and a decrease in adhesiveness to the substrate due to thermal load. Furthermore, by setting the number-average molecular weight at or below the upper limit, an increase in the viscosity of the polyurethane resin solution (varnish) is suppressed, making it easier to handle.

[0023] When the polyurethane resin is taken as 100% by mass, the total amount of the polycarbonate polyol (A), the organic diisocyanate (B), and the chain extender (C) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more, and may even be 100% by mass. By keeping it in the above range, excellent adhesiveness and heat resistance can be exhibited.

[0024] In a method for synthesizing the polyurethane resin used in the present invention, a polycarbonate diol (A) having a specific skeleton, an organic diisocyanate (B), and a chain extender (C) may be charged into a reaction vessel all at once or in portions. The reaction is preferably carried out so that the ratio of functional groups (isocyanate groups / hydroxyl groups) is 1 or less, where the total hydroxyl value of the polycarbonate diol (A) and the chain extender (C) in the system and the total isocyanate groups of the organic diisocyanate (B) is 0.99 or less, more preferably 0.98 or less. Furthermore, the ratio is preferably 0.90 or more, more preferably 0.94 or more, and even more preferably 0.96 or more. This reaction can be carried out in the presence or absence of a solvent inert to the isocyanate groups, allowing for stable production. The solvent is not particularly limited, but examples thereof include ester solvents (ethyl acetate, butyl acetate, ethyl butyrate, etc.), ether solvents (dioxane, tetrahydrofuran, diethyl ether, etc.), ketone solvents (cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, etc.), aromatic hydrocarbon solvents (benzene, toluene, xylene, etc.), and mixed solvents thereof. As the reaction apparatus, not only a reaction vessel (reaction can) equipped with a stirring device but also a mixing / kneading apparatus such as a kneader or a twin-screw extruder can be used.

[0025] To promote the urethanization reaction described above, a catalyst used in a typical urethanization reaction can be used. Examples of the catalyst include tin-based catalysts (trimethyltin laurate, dimethyltin dilaurate, trimethyltin hydroxide, dimethyltin dihydroxide, stannous octoate, etc.), bismuth-based catalysts, lead-based catalysts (red oleate, red-2-ethylhexanoate, etc.), and amine-based catalysts (triethylamine, tributylamine, morpholine, diazabicyclooctane, etc.). These catalysts may be used alone or in combination of two or more.

[0026] <Crosslinking agent> The crosslinking agent used in the present invention is not particularly limited as long as it reacts with the polyurethane resin to form a crosslink. It is preferably a compound having two or more functional groups per molecule, and examples of the functional groups include an isocyanate group, an epoxy group, an amino group, a methylol group, an alkoxymethyl group, an imino group, a metal chelate group, and an aziridinyl group. Specific examples of the compound include a polyfunctional isocyanate compound, a polyfunctional epoxy compound, a polyfunctional melamine compound, a metal crosslinking agent, and a polyfunctional aziridine compound.

[0027] A polyfunctional isocyanate compound is a compound having two or more isocyanate groups per molecule. Specific examples include diisocyanate compounds such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate, orthoxylylene diisocyanate, metaxylylene diisocyanate, paraxylylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 1,8-naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate, and polyisocyanate compounds formed from these, as well as urethane-modified, allophanate-modified, urea-modified, biuret-modified, uretdione-modified, uretoimine-modified, isocyanurate-modified, and carbodiimide-modified organic diisocyanates. These may be used alone or in combination of two or more.

[0028] A polyfunctional epoxy compound is a compound having two or more epoxy groups per molecule. Specific examples include diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, and polyalkylene glycols; polyglycidyl ethers of aliphatic polyols such as sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, and trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol; and diglycidyl esters or polyglycidyl esters of aliphatic or aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid. Other examples include diglycidyl ethers or polyglycidyl ethers of polyhydric phenols such as resorcinol, bis-(p-hydroxyphenyl)methane, 2,2-bis-(p-hydroxyphenyl)propane, tris-(p-hydroxyphenyl)methane, and 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane; N-glycidyl derivatives of amines such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, and N,N,N',N'-tetraglycidyl-bis-(p-aminophenyl)methane; triglycidyl derivatives of aminophenol; triglycidyl tris(2-hydroxyethyl)isocyanurate; triglycidyl isocyanurate; orthocresol epoxy; phenol novolac epoxy; and bisphenol-type polyfunctional epoxy compounds. These may be used alone or in combination of two or more.

[0029] Examples of metal crosslinking agents include metal chelate compounds in which acetylacetone, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, methyl salicylate, etc. are coordinated with metals such as aluminum, zinc, cadmium, nickel, cobalt, copper, calcium, barium, titanium, manganese, iron, lead, zirconium, chromium, and tin. These may be used alone or in combination of two or more.

[0030] A polyfunctional aziridine compound is a compound having two or more aziridine groups per molecule. Specific examples include N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, bisisophthaloyl-1-(2-methylaziridine), tri-1-aziridinylphosphone oxide, and N,N'-diphenylethane-4,4'-bis(1-aziridinecarboxamide). These compounds may be used alone or in combination.

[0031] The crosslinking agent is preferably a polyfunctional isocyanate compound, more preferably xylylene diisocyanate or a modified product thereof.

[0032] The content of the crosslinking agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of the polyurethane resin. The content is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less. By keeping the content within the above range, excellent adhesiveness and heat resistance can be achieved.

[0033] <Adhesive composition> The adhesive composition of the present invention is a composition containing the polyurethane resin and the crosslinking agent. The content of the polyurethane resin in the solid content of the adhesive composition is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. It is also preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less. By containing the polyurethane resin within the above range, excellent adhesive properties and heat resistance can be achieved.

[0034] The adhesive composition of the present invention can be diluted with an organic solvent to form a varnish. Examples of organic solvents include, but are not limited to, ester solvents (e.g., ethyl acetate, butyl acetate, ethyl butyrate), ether solvents (e.g., dioxane, tetrahydrofuran, diethyl ether), ketone solvents (e.g., cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone), aromatic hydrocarbon solvents (e.g., benzene, toluene, xylene), and mixtures thereof. The organic solvent is preferably used in an amount of 50 parts by mass or more, more preferably 100 parts by mass or more, and even more preferably 200 parts by mass or more, per 100 parts by mass of polyurethane resin. The amount is preferably 2000 parts by mass or less, more preferably 1000 parts by mass or less, and even more preferably 500 parts by mass or less. Within the above ranges, the adhesive composition exhibits good storage stability and improves its applicability to substrates. It is also advantageous in terms of cost.

[0035] The adhesive composition may contain known additives such as ultraviolet absorbers, antioxidants, flame retardants, and fillers, within limits that do not impair the effects of the present invention. [Example]

[0036] The present invention will be described below using examples, but the present invention is not limited to these examples. Unless otherwise specified, in the examples, "parts" simply means "parts by mass" and "%" means "% by mass." Furthermore, each measurement item was performed according to the following methods.

[0037] <Number average molecular weight (Mn)> 4 mg of sample (polycarbonate polyol (A) or polyurethane resin) was dissolved in 4 ml of tetrahydrofuran (with 5 mM tetrabutylammonium chloride added), and then filtered through a 0.2 μm membrane filter to obtain a sample solution. The sample solution was analyzed by gel permeation chromatography. A TOSOH HLC-8220 was used with a differential refractive index detector, and measurements were performed at a flow rate of 1 mL / min and a column temperature of 40°C. Monodisperse polystyrene was used as the molecular weight standard, and the number average molecular weight was calculated as a standard polystyrene equivalent value, excluding portions corresponding to molecular weights less than 1,000.

[0038] <Glass transition temperature (Tg)> The glass transition temperature was determined as the temperature at the inflection point of the storage modulus (E') based on the temperature dependence of dynamic viscoelasticity. The obtained polyurethane resin solution was applied to a polypropylene film (P2161 manufactured by Toyobo Co., Ltd., thickness 50 μm) to a wet film thickness (thickness before drying) of 200 μm, and heated at 120°C for 1 hour to volatilize (dry) the solvent. Next, the polyurethane resin solution was dried and the film was peeled off from the polypropylene film to obtain a polyurethane resin sample film. The glass transition temperature of the sample film was measured. A dynamic viscoelasticity measuring device DVA-220 manufactured by IT Measurement & Control Co., Ltd. was used to measure the temperature dependence from 0°C to 150°C (4°C / min, 10 Hz).

[0039] Polyurethane resin (U1) manufacturing example A reaction vessel equipped with a thermometer, stirrer, reflux condenser, and distillation tube was charged with 100 parts of UC-100 (polycarbonate diol manufactured by Ube Industries), 5 parts of neopentyl glycol, and 204 parts of methyl ethyl ketone (MEK). After dissolution, 31 parts of isophorone diisocyanate was added and stirred to obtain a homogeneous solution. 0.5 parts of BiCAT8210 (manufactured by The Shepherd Chemical Company) was then added as a catalyst and the mixture was allowed to react at 75°C for 5 hours. After the reaction was completed, 113 parts of methyl ethyl ketone (MEK) was added and stirred to obtain a solution of polyurethane resin (U1) with the desired solids concentration (NV) of 30% by mass. The properties of the polyurethane resin (U1) obtained in this manner are shown in Table 1.

[0040] Production examples of polyurethane resins (U2) to (U10) Polyurethane resins (U2) to (U-10) were obtained in the same manner as in the production example of polyurethane resin (U1), except that the types and blending ratios of raw materials were changed. Their properties are shown in Table 1.

[0041] [Table 1]

[0042] Examples 1 to 8, Comparative Examples 1 to 3 Laminates were prepared using the polyurethane resins (U1) to (U10), and the initial adhesive strength (adhesion) and heat resistance were evaluated. For Example 8, 4 parts by mass (3 parts by mass in terms of solid content) of D-110N (manufactured by Mitsui Chemicals, solid content concentration 75% by mass) was added as a crosslinking agent to 100 parts by mass of the polyurethane resin solution (30 parts by mass in terms of solid content) for evaluation.

[0043] Fabrication of laminate A solution of polyurethane resin (P1) was applied to a polycarbonate film (Sumitomo Bakelite, EC105, 0.5 mm) using a bar coater to a dry film thickness (film thickness after drying) of 5 μm, and the film was heated at 120°C for 3 minutes to volatilize (dry). Next, a polycarbonate film (Sumitomo Bakelite, EC105, 0.5 mm) was pressure-bonded (dry-laminated) to the polyurethane resin surface of the film using a dry laminator. Dry lamination was performed at a roll temperature of 120°C, a roll load of 3 kg / cm, and a pressure-bonded material speed of 1 m / min. Next, aging was performed at 80°C for 1 hour to obtain a laminate.

[0044] Initial adhesive strength (adhesion) test The laminate was cut into strips with a width of 15 mm, and peeled using a Tensilon (registered trademark) (UTM-IV, manufactured by Toyo Sokki Co., Ltd.) (T-type peel peeling, pulling speed 100 mm / min), and the peeling behavior was observed to evaluate the adhesiveness. The evaluation results are shown in Table 2. (evaluation) ○: Cohesive failure of adhesive or material failure occurred. △: Interfacial peeling occurred and the adhesive strength was 10 N / 15 mm. ×: The adhesive strength was less than 10 N / 15 mm.

[0045] Heat Resistance Test The laminate was treated (left to stand) at 105° C. for 300 hours, and the adhesiveness was evaluated in the same manner as in the initial adhesive strength test. (evaluation) ⊚: No lifting occurred, and adhesive cohesive failure or material failure occurred. ◯: No lifting occurred, mainly cohesive peeling, but some interfacial peeling occurred. △: No lifting occurred, and interfacial peeling occurred. ×: Floating occurred.

[0046] [Table 2]

[0047] The compounds used in Tables 1 and 2 are as follows: UC-100: Polycarbonate diol based on 1,4-cyclohexanedimethanol, manufactured by Ube Industries, Ltd., number average molecular weight = 1000, content of the structure represented by general formula (1) in polycarbonate polyol (A) 100 mol% UH-100: Polycarbonate diol based on 1,6-hexanediol, manufactured by Ube Industries, Ltd., number average molecular weight = 1000, content of the structure represented by general formula (1) in polycarbonate polyol (A) is 0 mol% PH-100: Polycarbonate diol manufactured by Ube Industries, based on 1,6-hexanediol and 1,5-pentanediol, number average molecular weight = 1000, content of the structure represented by general formula (1) in polycarbonate polyol (A) is 0 mol% UM-90 (3 / 1): Polycarbonate diol manufactured by Ube Industries, Ltd., based on 1,4-cyclohexanedimethanol and 1,6-hexanediol, number average molecular weight = 900, content of the structure represented by general formula (1) in polycarbonate polyol (A) 75 mol% UM-90 (1 / 1): Polycarbonate diol manufactured by Ube Industries, Ltd., based on 1,4-cyclohexanedimethanol and 1,6-hexanediol, number average molecular weight = 900, content of the structure represented by general formula (1) in polycarbonate polyol (A) 50 mol% D-110N: Mitsui Chemicals, metaxylylene diisocyanate trimethylolpropane adduct, solid content 75% by mass IPDI: Isophorone diisocyanate MDI: Diphenylmethane diisocyanate HDI: Hexamethylene diisocyanate NPG: Neopentyl glycol HD: 1,6-hexanediol

Claims

1. The polyurethane resin contains, as copolymerization components, polycarbonate polyol (A), organic diisocyanate (B), and chain extender (C), wherein the polycarbonate polyol (A) contains 60 mol % or more of a structure represented by the following general formula (1), the polyurethane resin has a glass transition temperature of 50°C or higher, the chain extender (C) is neopentyl glycol, and the copolymerization amount of the chain extender (C) is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the polycarbonate polyol (A): [C1] (In general formula (1), n ​​represents an integer of 1 to 20.)

2. 2. The polyurethane resin according to claim 1, wherein the organic diisocyanate (B) is isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, or hexamethylene diisocyanate.

3. An adhesive composition comprising the polyurethane resin according to claim 1 or 2 and a crosslinking agent.

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