Polyurethane adhesive composition and polyurethane adhesive

Abstract

To provide a polyurethane adhesive composition for creating a polyurethane adhesive that excels in all of contamination resistance, water resistance, and moist-heat resistance, and to provide a polyurethane adhesive that excels in all of contamination resistance, water resistance and moist-heat resistance.SOLUTION: A polyurethane adhesive composition contains a polyol component (A) and a polyisocyanate component (B). The polyol component (A) contains a polyurethane polyol (a). The polyurethane polyol (a) contains a reaction product from a raw material polyol (a1) and a raw material polyisocyanate (a2). The raw material polyol (a1) contains a polyether polyol (a1-1) with a number average molecular weight of 1000 or more and 3000 or less and a polyester polyol (a1-2) with a number average molecular weight of 500 or more and less than 1000.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyurethane adhesive composition and a polyurethane adhesive.

Background Art

[0002] A polyurethane adhesive is a resin cured product having adhesiveness. The polyurethane adhesive is used, for example, in the fields of information equipment, housing, building materials, automobiles, railways, daily life, and healthcare.

[0003] The polyurethane adhesive is formed by reacting and curing a polyurethane adhesive composition (uncured resin composition). The polyurethane adhesive composition contains, for example, a polyol component and a polyisocyanate component.

[0004] As the polyurethane adhesive composition, for example, the following adhesive composition (uncured resin composition) has been proposed. This adhesive composition is applied to a substrate and dried to form an adhesive layer (resin cured product). The adhesive composition contains a polyurethane polyol (A), an isocyanate curing agent (B), a plasticizer (C), an antioxidant, an antistatic agent, a polyfunctional polyol, and a solvent. The polyurethane polyol contains a reaction product of a polyol (a) and a polyisocyanate (b). The polyol (a) contains a polyester polyol having a number average molecular weight of 1000 and a polyether polyol having a number average molecular weight of 1000. The polyisocyanate (b) contains hexamethylene diisocyanate. The isocyanate curing agent contains a trimethylolpropane adduct of hexamethylene diisocyanate (see, for example, Patent Document 1 (Examples 21 and Synthesis Example 3)).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] On the other hand, polyol (a), the raw material for the polyurethane polyol described above, contains a polyester polyol having a relatively high number average molecular weight (1000 or more) and a polyether polyol having a relatively high number average molecular weight (1000 or more). Therefore, the adhesive obtained using the polyurethane polyol described above has the drawback of being easily contaminated. Thus, improvement in the contaminated properties of the adhesive is required. Furthermore, the adhesive is required to have excellent water resistance and heat and humidity resistance.

[0007] The present invention relates to a polyurethane adhesive composition for obtaining a polyurethane adhesive that combines excellent stain resistance, excellent water resistance, and excellent heat and humidity resistance, and to a polyurethane adhesive that combines excellent stain resistance, excellent water resistance, and excellent heat and humidity resistance. [Means for solving the problem]

[0008] The present invention [1] is a polyurethane adhesive composition containing a polyol component (A) and a polyisocyanate component (B), wherein the polyol component (A) contains a polyurethane polyol (a), the polyurethane polyol (a) contains a reaction product of a raw material polyol (a1) and a raw material polyisocyanate (a2), and the raw material polyol (a1) contains a polyether polyol (a1-1) with a number average molecular weight of 1000 or more and 3000 or less, and a polyester polyol (a1-2) with a number average molecular weight of 500 or more and less than 1000, and the present invention includes a polyurethane adhesive composition.

[0009] The present invention [2] includes the polyurethane adhesive composition described in [1] above, wherein the average number of hydroxyl groups of the polyether polyol (a1-1) is 3 and the average number of hydroxyl groups of the polyester polyol (a1-2) is 2.

[0010] The present invention [3] comprises a polyurethane adhesive composition according to [1] or [2] above, wherein the polyester polyol (a1-2) contains a condensate of a low molecular weight polyol and a polybasic acid, and the low molecular weight polyol contains neopentyl glycol.

[0011] The present invention [4] includes a polyurethane adhesive formed from a polyurethane adhesive composition described in any one of the above [1] to [3]. [Effects of the Invention]

[0012] The polyurethane adhesive composition of the present invention contains a polyurethane polyol (a) as polyol component (A). The raw material polyol (a1) of polyurethane polyol (a) contains a polyester polyol (a1-1) with a number average molecular weight of 500 or more and less than 1000, and a polyether polyol (a1-2) with a number average molecular weight of 1000 or more and 3000 or less. Therefore, according to the above polyurethane adhesive composition, a polyurethane adhesive can be obtained that combines excellent stain resistance, excellent water resistance, and excellent heat and humidity resistance.

[0013] The polyurethane adhesive of the present invention is formed from the above-described polyurethane adhesive composition. Therefore, the above-described polyurethane adhesive possesses excellent stain resistance, excellent water resistance, and excellent heat and humidity resistance. [Modes for carrying out the invention]

[0014] 1. Polyurethane adhesive composition The polyurethane adhesive composition of the present invention is an uncured resin composition. The polyurethane adhesive composition contains a polyol component (A) and a polyisocyanate component (B).

[0015] More specifically, the polyurethane adhesive composition is, for example, a two-component curable polyurethane adhesive composition. The two-component curable polyurethane adhesive composition comprises a polyol component (A) as the main component and a polyisocyanate component (B) as the curing agent, in separate packages. The main component (polyol component (A)) and the curing agent (polyisocyanate component (B)) are blended together when the two-component curable polyurethane adhesive composition is used, as will be described later.

[0016] (1) Polyol component (A) The polyol component (A) contains macropolyol (A1). Preferably, the polyol component (A) consists of macropolyol (A1).

[0017] Macropolyols (A1) are relatively high molecular weight organic compounds having two or more hydroxyl groups in their molecules. The number-average molecular weight of macropolyols (A1) is, for example, greater than 400 and less than or equal to 20,000. The number-average molecular weight can be calculated from the hydroxyl group equivalent and the average number of hydroxyl groups using known methods. The number-average molecular weight can also be measured as polystyrene-equivalent molecular weight by gel permeation chromatography (the same applies hereafter).

[0018] Macropolyol (A1) contains polyurethane polyol (a). In other words, polyol component (A) contains polyurethane polyol (a).

[0019] Polyurethane polyol (a) is a reaction product of raw material polyol (a1) and raw material polyisocyanate (a2), and has hydroxyl groups at the molecular ends.

[0020] The raw material polyol (a1) contains a polyether polyol (a1-1) with a number average molecular weight of 1000 to 3000 and a polyester polyol (a1-2) with a number average molecular weight of 500 to less than 1000.

[0021] Examples of the polyether polyol (a1-1) include polyoxyalkylene (2 to 3 carbon atoms) polyol and polyoxytetramethylene ether polyol.

[0022] Examples of the polyoxyalkylene (2 to 3 carbon atoms) polyol include polyoxyethylene polyol, polyoxypropylene polyol, polyoxytriethylene polyol, and polyoxyethylene·polyoxypropylene polyol (random or block copolymer).

[0023] Examples of the polytetramethylene ether polyol include a ring-opening polymer obtained by cationic polymerization of tetrahydrofuran (crystalline polytetramethylene ether glycol). Further, examples of the polytetramethylene ether polyol include amorphous polytetramethylene ether glycol. The amorphous polytetramethylene ether glycol is obtained by copolymerization of tetrahydrofuran with an alkyl-substituted tetrahydrofuran and / or a dihydric alcohol. Note that crystalline means the property of being solid at 25°C. Also, amorphous means the property of being liquid at 25°C.

[0024] The polyether polyol (a1-1) can be used alone or in combination of two or more. As the polyether polyol (a1-1), preferably, polyoxyalkylene (2 to 3 carbon atoms) polyol is mentioned, and more preferably, polyoxypropylene polyol is mentioned.

[0025] The number-average molecular weight of polyether polyol (a1-1) is higher than that of polyester polyol (a1-2), which will be described later. More specifically, from the viewpoint of water resistance, the number-average molecular weight of polyether polyol (a1-1) is 1000 or more, preferably 1200 or more, more preferably 1500 or more, even more preferably 1800 or more, even more preferably 2000 or more, and particularly preferably 2500 or more. Furthermore, from the viewpoint of stain resistance and heat and humidity resistance, the number-average molecular weight of polyether polyol (a1-1) is 3000 or less, preferably 2950 or less, more preferably 2900 or less, and even more preferably 2850 or less.

[0026] The average number of hydroxyl groups in polyether polyol (a1-1) is, for example, 2 or more, preferably 2.5 or more. Alternatively, the average number of hydroxyl groups in polyether polyol (a1-1) is, for example, 6 or less, preferably 4 or less.

[0027] The average number of hydroxyl groups of the polyether polyol (a1-1) is preferably higher than that of the polyester polyol (a1-2) described later. More specifically, the average number of hydroxyl groups of the polyether polyol (a1-1) is particularly preferably 3 from the viewpoint of stain resistance, water resistance and heat and humidity resistance.

[0028] Furthermore, when two or more types of polyether polyols (a1-1) are used in combination, the number-average molecular weight and average number of hydroxyl groups of the polyether polyol (a1-1) are the same as the number-average molecular weight and average number of hydroxyl groups of the mixture of the two or more types of polyether polyols (a1-1).

[0029] The content of polyether polyol (a1-1) is adjusted, for example, based on the number of hydroxyl groups. More specifically, the proportion of hydroxyl groups derived from polyether polyol (a1-1) relative to the total moles of hydroxyl groups derived from polyether polyol (a1-1) and polyester polyol (a1-2) is, for example, 30 mol% or more, preferably 40 mol% or more, and more preferably 50 mol% or more. Also, the proportion of hydroxyl groups derived from polyether polyol (a1-1) relative to the total moles of hydroxyl groups derived from polyether polyol (a1-1) and polyester polyol (a1-2) is, for example, 80 mol% or less, preferably 70 mol% or less, and more preferably 60 mol% or less.

[0030] Examples of polyester polyols (a1-2) include condensed polyester polyols and ring-opening polyester polyols. Examples of condensed polyester polyols include condensates of low molecular weight polyols and polybasic acids. Examples of ring-opening polyester polyols include ring-opening polymers of lactones and / or lactides. Preferably, polyester polyols (a1-2) are condensed polyester polyols.

[0031] In other words, the polyester polyol (a1-2) preferably contains a condensate of a low molecular weight polyol and a polybasic acid.

[0032] Low molecular weight polyols are organic compounds with two or more hydroxyl groups in their molecule and a relatively low molecular weight. The molecular weight of low molecular weight polyols is, for example, 40 or more and less than 400, preferably 300 or less. Examples of low molecular weight polyols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric or higher alcohols include pentaerythritol and diglycerin. These can be used individually or in combination of two or more types.

[0033] As low molecular weight polyols, dihydric alcohols are preferred. As dihydric alcohols, branched dihydric alcohols are preferred. Among the above dihydric alcohols, examples of branched dihydric alcohols include neopentyl glycol and 3-methyl-1,5-pentanediol. As low molecular weight polyols, neopentyl glycol is particularly preferred from the viewpoint of stain resistance, water resistance and heat and humidity resistance.

[0034] Examples of polybasic acids include saturated aliphatic dicarboxylic acids, unsaturated aliphatic dicarboxylic acids, aromatic dicarboxylic acids, alicyclic dicarboxylic acids, other carboxylic acids, acid anhydrides, and acid halides. Examples of saturated aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, 1,1-dimethyl-1,3-dicarboxypropane, 3-methyl-3-ethylglutaric acid, azelaic acid, and sebacic acid. Examples of unsaturated aliphatic dicarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Examples of aromatic dicarboxylic acids include orthophthalic acid, isophthalic acid, terephthalic acid, toluenedicarboxylic acid, and naphthalenedicarboxylic acid. Examples of alicyclic dicarboxylic acids include hexahydrophthalic acid. Examples of other carboxylic acids include dimer acids, hydrogenated dimer acids, and hetic acid. Examples of acid anhydrides include oxalic acid anhydride, succinic acid anhydride, maleic acid anhydride, phthalic acid anhydride, alkyl succinic acid anhydride, tetrahydrophthalic acid anhydride, and trimellitic acid anhydride. Examples of acid halides include oxalic acid dichloride, adipic acid dichloride, and sebacate acid dichloride. These can be used individually or in combination of two or more types.

[0035] The method for condensing a low molecular weight polyol with a polybasic acid is not particularly limited. For example, the low molecular weight polyol and the polybasic acid can be esterified in appropriate proportions. In the esterification, a known esterification catalyst can be used as needed. This produces a condensed polyester polyol. Alternatively, the condensed polyester polyol can also be produced, for example, by a transesterification reaction between the alkyl ester of the polybasic acid described above and the low molecular weight polyol described above.

[0036] Polyester polyols (a1-2) can be used alone or in combination of two or more types. Preferably, polyester polyols (a1-2) are condensed polyester polyols, and more preferably, condensates of a low molecular weight polyol containing neopentyl glycol and a polybasic acid.

[0037] The number-average molecular weight of polyester polyol (a1-2) is lower than that of the polyether polyol (a1-1) described above. More specifically, from the viewpoint of stain resistance, the number-average molecular weight of polyester polyol (a1-2) is less than 1000, preferably 950 or less, more preferably 900 or less, and even more preferably 850 or less. Furthermore, from the viewpoint of water resistance and heat and humidity resistance, the number-average molecular weight of polyester polyol (a1-2) is 500 or more, preferably 600 or more, and more preferably 700 or more.

[0038] The average number of hydroxyl groups in polyester polyol (a1-2) is, for example, 2 or more. Alternatively, the average number of hydroxyl groups in polyester polyol (a1-2) is, for example, 6 or less, preferably 4 or less, more preferably 3 or less, and even more preferably 2.5 or less.

[0039] The average number of hydroxyl groups in polyester polyol (a1-2) is preferably lower than the average number of hydroxyl groups in the polyether polyol (a1-1) described above. More specifically, the average number of hydroxyl groups in polyester polyol (a1-2) is particularly preferably 2 from the viewpoint of stain resistance, water resistance and heat and humidity resistance.

[0040] Furthermore, when two or more types of polyester polyols (a1-2) are used in combination, the number-average molecular weight and average number of hydroxyl groups of the polyester polyol (a1-2) are the same as the number-average molecular weight and average number of hydroxyl groups of the mixture of the two or more types of polyester polyols (a1-2).

[0041] The content of polyester polyol (a1-2) is adjusted, for example, based on the number of hydroxyl groups. More specifically, the proportion of hydroxyl groups derived from polyester polyol (a1-2) relative to the total moles of hydroxyl groups derived from polyether polyol (a1-1) and polyester polyol (a1-2) is, for example, 20 mol% or more, preferably 30 mol% or more, and more preferably 40 mol% or more. Also, the proportion of hydroxyl groups derived from polyester polyol (a1-2) relative to the total moles of hydroxyl groups derived from polyether polyol (a1-1) and polyester polyol (a1-2) is, for example, 70 mol% or less, preferably 60 mol% or less, and more preferably 50 mol% or less.

[0042] Furthermore, the content of hydroxyl groups derived from polyester polyol (a1-2) is, for example, 50 moles or more, preferably 60 moles or more, per 100 moles of hydroxyl groups derived from polyether polyol (a1-1). Also, the content of hydroxyl groups derived from polyester polyol (a1-2) is, for example, 100 moles or less, preferably 90 moles or less, per 100 moles of hydroxyl groups derived from polyether polyol (a1-1).

[0043] The raw material polyol (a1) may contain other raw material polyols. The other raw material polyols are polyols other than the polyether polyol (a1-1) and polyester polyol (a1-2) described above.

[0044] Other raw material polyols include, for example, the low molecular weight polyols mentioned above, and known macropolyols (excluding polyether polyols and polyester polyols).

[0045] From the viewpoint of stain resistance, water resistance, and heat and humidity resistance, the content of other raw material polyols is, for example, less than 50% by mass, preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 0% by mass, relative to the total amount of raw material polyol (a1).

[0046] In other words, the raw material polyol (a1) preferably does not contain any other raw material polyols and consists of the above-mentioned polyether polyol (a1-1) and the above-mentioned polyester polyol (a1-2).

[0047] Examples of the raw material polyisocyanate (a2) include polyisocyanate monomers and polyisocyanate derivatives.

[0048] Examples of polyisocyanate monomers include aliphatic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates. These polyisocyanate monomers can be used individually or in combination of two or more types.

[0049] Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 1,2-propane diisocyanate, 1,2-butane diisocyanate, 2,3-butane diisocyanate, 1,3-butane diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caproate. These can be used individually or in combination of two or more.

[0050] Furthermore, aliphatic polyisocyanates also include alicyclic polyisocyanates. Examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), and methylenebis(cyclohexyl isocyanate) (H 12 Examples include MDI and bis(isocyanatomethyl)cyclohexane (H6XDI). These can be used alone or in combination of two or more.

[0051] Examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), toluidine diisocyanate (TODI), paraphenylenedi diisocyanate, and naphthalene diisocyanate (NDI). These can be used individually or in combination of two or more types.

[0052] Examples of aromatic aliphatic polyisocyanates include xylylene diisocyanate (XDI) and tetramethyl xylylene diisocyanate (TMXDI). These can be used individually or in combination of two or more types.

[0053] Examples of polyisocyanate derivatives include modified products obtained by modifying the above-mentioned polyisocyanate monomers using known methods. Examples of polyisocyanate derivatives include polymers, isocyanurate modified products, allophanate modified products, polyol adducts, biuret modified products, urea modified products, oxadiazinetrione modified products, and carbodiimide modified products. Polymethylene polyphenylene polyisocyanate is also an example of a polyisocyanate derivative. These polyisocyanate derivatives can be used individually or in combination of two or more types.

[0054] Preferably, the raw material polyisocyanate (a2) is a polyisocyanate monomer, more preferably an aliphatic polyisocyanate monomer, and even more preferably hexamethylene diisocyanate and pentamethylene diisocyanate. From the viewpoint of stain resistance, water resistance and heat and humidity resistance, pentamethylene diisocyanate is particularly preferred. Furthermore, from the viewpoint of availability and low cost, hexamethylene diisocyanate is particularly preferred.

[0055] Polyurethane polyol (a) is obtained by reacting raw material polyol (a1) with raw material polyisocyanate (a2) in the following manner.

[0056] More specifically, to obtain polyurethane polyol (a), for example, a urethane reaction is carried out between raw material polyol (a1) and raw material polyisocyanate (a2) under an inert gas atmosphere.

[0057] In the urethane formation reaction, the equivalent ratio (NCO / OH) of the isocyanate groups of the raw material polyisocyanate (a2) to the hydroxyl groups of the raw material polyol (a1) is, for example, 0.5 or more, preferably 0.6 or more. Also, the equivalent ratio (NCO / OH) of the isocyanate groups of the raw material polyisocyanate (a2) to the hydroxyl groups of the raw material polyol (a1) is, for example, less than 1.0, preferably 0.9 or less.

[0058] In the urethane reaction, known urethane catalysts are added as needed. Examples of urethane catalysts include amines, organometallic compounds, and potassium salts. These are used individually or in combination of two or more. The proportion of urethane catalysts added is set appropriately according to the purpose and application.

[0059] The reaction conditions for the urethane formation reaction are not particularly limited. For example, the reaction temperature may be between 40°C and 100°C. The reaction time may be between 2 hours and 24 hours. As a result, polyurethane polyol (a) is obtained as the reaction product of raw material polyol (a1) and raw material polyisocyanate (a2).

[0060] The number-average molecular weight of polyurethane polyol (a) is, for example, greater than 400, preferably 500 or more, more preferably 1000 or more, and even more preferably 1500 or more. Alternatively, the number-average molecular weight of polyurethane polyol (a) is, for example, 20000 or less, preferably 15000 or less, more preferably 10000 or less, and even more preferably 5000 or less.

[0061] The average number of hydroxyl groups in polyurethane polyol (a) is, for example, 2 or more, preferably more than 2, and more preferably 2.1 or more. Alternatively, the average number of hydroxyl groups in polyurethane polyol (a) is, for example, 4 or less, preferably 3 or less, more preferably less than 3, and even more preferably 2.8 or less.

[0062] In polyol component (A), macropolyol (A1) may include other macropolyols. Other macropolyols are macropolyols other than polyurethane polyol (a) described above. Examples of other macropolyols include known polyether polyols, known polyester polyols, and known polycarbonate polyols. These can be used individually or in combination of two or more.

[0063] In the polyol component (A), the macropolyol (A1) preferably does not contain other macropolyols. That is, in the polyol component (A), the macropolyol (A1) preferably consists of the polyurethane polyol (a) described above.

[0064] The number-average molecular weight of macropolyol (A1) is, for example, greater than 400, preferably 500 or more, more preferably 1000 or more, and even more preferably 1500 or more. Alternatively, the number-average molecular weight of macropolyol (A1) may be 20000 or less, preferably 15000 or less, more preferably 10000 or less, and even more preferably 5000 or less.

[0065] The average number of hydroxyl groups in macropolyol (A1) is, for example, 2 or more, preferably more than 2, and more preferably 2.1 or more. Alternatively, the average number of hydroxyl groups in macropolyol (A1) is, for example, 4 or less, preferably 3 or less, more preferably less than 3, and even more preferably 2.8 or less.

[0066] The polyol component (A) may, if necessary, contain a low molecular weight polyol (A2) in addition to the macropolyol (A1) described above. Examples of low molecular weight polyols (A2) include the dihydric alcohol, trihydric alcohol, and tetrahydric alcohol described above. These can be used individually or in combination of two or more types.

[0067] Preferably, the polyol component (A) does not contain a low molecular weight polyol (A2). That is, the polyol component (A) preferably consists of a macropolyol (A1), and more preferably consists of the polyurethane polyol (a) described above.

[0068] The number-average molecular weight of polyol component (A) is, for example, greater than 400, preferably 500 or more, more preferably 1000 or more, and even more preferably 1500 or more. Alternatively, the number-average molecular weight of polyol component (A) may be 20000 or less, preferably 15000 or less, more preferably 10000 or less, and even more preferably 5000 or less.

[0069] The average number of hydroxyl groups of polyol component (A) is, for example, 2 or more, preferably more than 2, and more preferably 2.1 or more. Alternatively, the average number of hydroxyl groups of polyol component (A) is, for example, 4 or less, preferably 3 or less, more preferably less than 3, and even more preferably 2.8 or less.

[0070] The polyol component (A) may be dissolved and / or dispersed in an organic solvent. That is, the polyol component (A) may be prepared as a solution and / or dispersion. In other words, the main component of the two-component curable polyurethane adhesive composition may be a solution and / or dispersion of the polyol component (A) in an organic solvent.

[0071] Examples of organic solvents include ketones, nitriles, alkyl esters, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ethers, glycol ether esters, halogenated aliphatic hydrocarbons, and polar aprotons. These can be used individually or in combination of two or more. The mixing ratio of the organic solvents is set appropriately according to the purpose and application.

[0072] In the organic solvent solution and / or dispersion of polyol component (A), the solid content concentration of polyol component (A) is, for example, 30% by mass or more, preferably 40% by mass or more. Alternatively, in the organic solvent solution and / or dispersion of polyol component (A), the solid content concentration of polyol component (A) is, for example, less than 100% by mass, preferably 90% by mass or less.

[0073] (2) Polyisocyanate component (B) Examples of the polyisocyanate component (B) include polyisocyanate monomers and polyisocyanate derivatives.

[0074] Examples of polyisocyanate monomers include the aliphatic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates mentioned above. These polyisocyanate monomers can be used individually or in combination of two or more types.

[0075] Examples of polyisocyanate derivatives include modified products obtained by modifying the above-mentioned polyisocyanate monomers using known methods. Examples of polyisocyanate derivatives include polymers, isocyanurate modified products, allophanate modified products, polyol adducts, biuret modified products, urea modified products, oxadiazinetrione modified products, and carbodiimide modified products. Polymethylene polyphenylene polyisocyanate is also an example of a polyisocyanate derivative. These can be used individually or in combination of two or more types.

[0076] Preferably, polyisocyanate derivatives include isocyanurate modified forms, allophanate modified forms, polyol adducts, and biuret modified forms; more preferably, isocyanurate modified forms, allophanate modified forms, and polyol adducts; even more preferably, isocyanurate modified forms and polyol adducts; and particularly preferably, polyol adducts. In polyol adducts, for example, the low molecular weight polyols mentioned above can be used as polyols; preferably, trihydric alcohols; and more preferably, trimethylolpropane. These can be used alone or in combination of two or more.

[0077] Furthermore, from the viewpoint of stain resistance, water resistance, and heat and humidity resistance, the polyisocyanate component (B) is preferably a derivative of aliphatic polyisocyanate and a derivative of aromatic aliphatic polyisocyanate, and more preferably a derivative of hexamethylene diisocyanate, a derivative of pentamethylene diisocyanate, and a derivative of xylylene diisocyanate. From the viewpoint of stain resistance, even more preferably a derivative of pentamethylene diisocyanate and a derivative of xylylene diisocyanate. From the viewpoint of heat and humidity resistance, a derivative of xylylene diisocyanate is particularly preferred.

[0078] Specifically, the polyisocyanate component (B) preferably includes a polyol adduct of xylylene diisocyanate, an allophanate-modified xylylene diisocyanate, and an isocyanurate-modified xylylene diisocyanate; more preferably, a polyol adduct of xylylene diisocyanate and an isocyanurate-modified xylylene diisocyanate; and most preferably, a polyol adduct of xylylene diisocyanate.

[0079] The polyisocyanate component (B) may be dissolved and / or dispersed in the organic solvent described above. That is, the polyisocyanate component (B) may be prepared as a solution and / or dispersion. In other words, the curing agent of the two-component curable polyurethane adhesive composition may be a solution and / or dispersion of the polyisocyanate component (B) in an organic solvent.

[0080] In the organic solvent solution and / or dispersion of polyisocyanate component (B), the solid content concentration of polyisocyanate component (B) is, for example, 30% by mass or more, preferably 40% by mass or more. Alternatively, in the organic solvent solution and / or dispersion of polyisocyanate component (B), the solid content concentration of polyisocyanate component (B) is, for example, less than 100% by mass, preferably 90% by mass or less.

[0081] (3) Additives Polyurethane adhesive compositions may contain additives as needed. Examples of additives include urethane catalysts, antioxidants, UV absorbers, heat stabilizers, light stabilizers, crosslinking agents, antistatic agents, silane coupling agents, coating properties improvers, leveling agents, defoamers, curing accelerators, curing retarders, plasticizers, surfactants, pigments, fillers, organic particles, inorganic particles, metal particles, antifungal agents, processing aids, and anti-aging agents. These can be used individually or in combination of two or more types.

[0082] The additive may be contained in the polyol component (A), in the polyisocyanate component (B), or in both the polyol component (A) and the polyisocyanate component (B). The proportion of the additive is not particularly limited and can be set appropriately depending on the type of additive.

[0083] (4) Effects The polyurethane adhesive composition described above contains polyurethane polyol (a) as polyol component (A). The raw material polyol (a1) of polyurethane polyol (a) contains polyester polyol (a1-1) with a number average molecular weight of 500 or more and less than 1000, and polyether polyol (a1-2) with a number average molecular weight of 1000 or more and 3000 or less. Therefore, the polyurethane adhesive composition described above can be used to obtain a polyurethane adhesive that possesses excellent stain resistance, excellent water resistance, and excellent heat and humidity resistance.

[0084] 3. Polyurethane adhesive The polyurethane adhesive is formed from the polyurethane adhesive composition described above. More specifically, the polyurethane adhesive is obtained by curing (crosslinking) the polyurethane adhesive composition described above. That is, the polyurethane adhesive is a reaction product (cured resin) obtained by the reaction (curing reaction) between a polyol component (A) and a polyisocyanate component (B).

[0085] Furthermore, polyurethane adhesives possess tackiness (pressure-sensitive adhesion and tackiness). In other words, the reaction product (cured resin) of the polyol component (A) and the polyisocyanate component (B) is tacky. Polyurethane adhesives are distinguished from polyurethane adhesives (polyurethane resins that adhere to substrates due to a urethane reaction).

[0086] There are no particular limitations on the method for obtaining the polyurethane adhesive, but for example, the above polyurethane adhesive composition may be applied to the surface of a substrate and heat-cured.

[0087] More specifically, in this method, if the polyurethane adhesive composition is a two-component curing type polyurethane adhesive composition, first, a polyol component (A) as the main component and a polyisocyanate component (B) as the curing agent are blended together.

[0088] The mixing ratio of polyol component (A) and polyisocyanate component (B) is adjusted according to the equivalent ratio. For example, from the viewpoint of obtaining excellent adhesive strength, the equivalent ratio (NCO / OH) of isocyanate groups of polyisocyanate component (B) to hydroxyl groups of polyol component (A) is, for example, 0.03 or more, preferably 0.05 or more, and more preferably 0.1 or more. Also, from the viewpoint of obtaining excellent adhesive strength, the equivalent ratio (NCO / OH) of isocyanate groups of polyisocyanate component (B) to hydroxyl groups of polyol component (A) is, for example, 1.0 or less, preferably less than 1.0, more preferably 0.8 or less, and even more preferably 0.4 or less.

[0089] Furthermore, on a mass basis, the amount of polyisocyanate component (B) is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, per 100 parts by mass of polyol component (A). Also, the amount of polyisocyanate component (B) is, for example, 10 parts by mass or less, preferably 5 parts by mass or less, per 100 parts by mass of polyol component (A).

[0090] The mixing conditions for the polyol component (A) and the polyisocyanate component (B) are not particularly limited. The polyol component (A) and the polyisocyanate component (B) are mixed, for example, at room temperature. This yields a mixture of the polyol component (A) and the polyisocyanate component (B).

[0091] Furthermore, in this method, the above-mentioned additives (such as urethane catalysts) can be added to the mixture of polyol component (A) and polyisocyanate component (B) as needed. The additives may be added to polyol component (A) and / or polyisocyanate component (B) before mixing them. Alternatively, the additives may be added simultaneously with the mixing of polyol component (A) and polyisocyanate component (B). Alternatively, the additives may be added to the mixture after mixing polyol component (A) and polyisocyanate component (B). The mixing ratio of the additives is not particularly limited and can be set appropriately depending on the type of additive.

[0092] Furthermore, in this method, the viscosity of the mixture can be adjusted by adding the above-mentioned organic solvent to the mixture of polyol component (A) and polyisocyanate component (B) as needed. The amount of organic solvent added is not particularly limited and can be adjusted as appropriate.

[0093] This yields a mixture of polyurethane adhesive compositions (a mixture of polyol component (A) and polyisocyanate component (B)).

[0094] Next, in this method, a mixture of polyurethane adhesive compositions (a mixture of polyol component (A) and polyisocyanate component (B)) is applied to the substrate.

[0095] The substrate is not particularly limited, but examples include paper, cloth, leather, wood, resin sheets, rubber sheets, and metal sheets. Resin sheets are preferred as the substrate. The substrate may be surface-treated as needed. Examples of surface treatments include corona discharge treatment and primer treatment. The thickness of the substrate is not particularly limited and is set appropriately according to the purpose and application. The thickness of the substrate is, for example, 1 to 1000 μm.

[0096] The method of applying the polyurethane adhesive composition is not particularly limited. Examples of application methods include dip coating, spray coating, roll coating, doctor blade coating, screen printing, bar coating, and casting.

[0097] The above coating process forms a film of the polyurethane adhesive composition on the surface of the substrate. The dry thickness of the polyurethane adhesive composition film is, for example, 5 μm or more, preferably 8 μm or more. Alternatively, the dry thickness of the polyurethane adhesive composition film is, for example, 50 μm or less, preferably 20 μm or less.

[0098] Subsequently, in this method, the coating film of the polyurethane adhesive composition is heated. This causes the polyurethane adhesive composition to harden (crosslink).

[0099] The heating temperature is, for example, 23°C or higher, preferably 80°C or higher. The heating temperature is, for example, 180°C or lower, preferably 140°C or lower. The heating time is, for example, 30 seconds or more, preferably 1 minute or more. The heating time is, for example, 1 hour or less, preferably 0.5 hours or less.

[0100] The polyurethane adhesive composition hardens (crosslinks) on the substrate through the above coating and heating process. As a result, a polyurethane adhesive is obtained as a cured product (resin cured product) of the polyurethane adhesive composition (uncured resin composition).

[0101] The polyurethane adhesive is aged as needed. The aging temperature is, for example, 23°C or higher, preferably 40°C or higher. The aging temperature is, for example, 100°C or lower, preferably 80°C or lower. The aging time is, for example, 12 hours or more, preferably 1 day or more. The aging time is, for example, 14 days or less, preferably 7 days or less. The aging humidity (relative humidity) is, for example, 10% or higher, preferably 40% or higher. The aging humidity (relative humidity) is, for example, 80% or less, preferably 60% or less.

[0102] Furthermore, the polyurethane adhesive described above is formed from the polyurethane adhesive composition described above. Therefore, the polyurethane adhesive described above possesses excellent stain resistance, excellent water resistance, and excellent heat and humidity resistance.

[0103] Therefore, polyurethane adhesives are suitably used in various industrial fields where the above physical properties are required. For example, polyurethane adhesives are suitably used in the information equipment field, housing field, building materials field, automotive field, railway field, lifestyle field, and healthcare field. [Examples]

[0104] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass. Furthermore, specific numerical values ​​such as blending ratios (content), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the blending ratios (content), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0105] 1. Polyurethane polyol (a) (1) Raw material polyol (a1)

[0106] Preparation Example A-1: ​​Polyether Polyol A Actcol T-3000 (trade name, polyoxypropylene polyol, number average molecular weight 3000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals) and Actcol T-1500 (trade name, polyoxypropylene polyol, number average molecular weight 1500, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals) were prepared. 100 parts by mass of Actcol T-3000 and 11.1 parts by mass of Actcol T-1500 were mixed. A polyether polyol with a number average molecular weight of 2850 was obtained from this mixture. Hereinafter, this polyether polyol (number average molecular weight 2850, average number of hydroxyl groups 3) was referred to as polyether polyol A (polyether A, PPT2850).

[0107] Preparation Example A-2: Polyether Polyol B Actcol T-700 (trade name, polyoxypropylene polyol, number average molecular weight 700, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals) was prepared. This was referred to as polyether polyol B (polyether B, PPT700).

[0108] Preparation Example A-3 Polyether Polyol C Actcol T-1000 (trade name, polyoxypropylene polyol, number average molecular weight 1000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals) was prepared. This was referred to as polyether polyol C (polyether C, PPT1000).

[0109] Preparation Example A-4 Polyether Polyol D Actcol T-3000 (trade name, polyoxypropylene polyol, number average molecular weight 3000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals) was prepared. This was referred to as polyether polyol D (polyether D, PPT3000).

[0110] Preparation Example A-5 Polyether Polyol E Actcol T-4000 (trade name, polyoxypropylene polyol, number average molecular weight 4000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals) was prepared. This was referred to as polyether polyol E (polyether E, PPT4000).

[0111] Preparation Example A-6 Polyether Polyol F Actcol D-1000 (trade name, polyoxypropylene polyol, number average molecular weight 1000, average number of hydroxyl groups 2, manufactured by Mitsui Chemicals) was prepared. This was referred to as polyether polyol F (polyether F, PPG1000).

[0112] Preparation Example A-7 Polyether Polyol G Actcol D-3000 (trade name, polyoxypropylene polyol, number average molecular weight 3000, average number of hydroxyl groups 2, manufactured by Mitsui Chemicals) and Actcol D-1500 (trade name, polyoxypropylene polyol, number average molecular weight 1500, average number of hydroxyl groups 2, manufactured by Mitsui Chemicals) were prepared. 100 parts by mass of Actcol D-3000 and 11.1 parts by mass of Actcol D-1500 were mixed. A polyether polyol with a number average molecular weight of 2850 was obtained from this mixture. Hereinafter, this polyether polyol (number average molecular weight 2850, average number of hydroxyl groups 2) was referred to as polyether polyol G (polyether G, PPG2850).

[0113] Preparation Example A-8 Polyester Polyol A Takelac LNB800 (product name, abbreviation LNB800, polyester polyol, number average molecular weight 800, average number of hydroxyl groups 2, condensate of neopentyl glycol (NPG) and polybasic acid (adipic acid), manufactured by Mitsui Chemicals) was prepared. This was referred to as polyester polyol A (polyester A).

[0114] Preparation Example A-9 Polyester Polyol B Kuraray Polyol P510 (trade name, abbreviation P510, polyester polyol, number average molecular weight 500, average number of hydroxyl groups 2, condensate of 3-methyl-1-pentanediol (MPD) and nonanediol (ND) with a polybasic acid (adipic acid), manufactured by Kuraray) was prepared. This was referred to as Polyester Polyol B (Polyester B).

[0115] Preparation Example A-10 Polyester Polyol C Kuraray Polyol P1010 (trade name, abbreviation P1010, polyester polyol, number average molecular weight 1000, average number of hydroxyl groups 2, condensate of 3-methyl-1-pentanediol (MPD) and nonanediol (ND) with a polybasic acid (adipic acid), manufactured by Kuraray) was prepared. This was referred to as Polyester Polyol C (Polyester C).

[0116] Preparation Example A-11 Polyester Polyol D Takelac U21 (trade name, abbreviation U21, polyester polyol, number average molecular weight 450, average number of hydroxyl groups 3, condensate of trimethylolpropane (TMP) and a polybasic acid (fumaric acid), manufactured by Mitsui Chemicals) was prepared. This was referred to as polyester polyol D (polyester D).

[0117] Preparation Example A-12 Polyester Polyol E Takelac U253 (trade name, abbreviation U253, polyester polyol, number average molecular weight 650, average number of hydroxyl groups 3, condensate of trimethylolpropane (TMP) and a polybasic acid (fumaric acid), manufactured by Mitsui Chemicals) was prepared. This was referred to as polyester polyol E (polyester E).

[0118] Preparation Example A-13 HDI Hexamethylene diisocyanate (monomer) was prepared.

[0119] 2. Polyisocyanate component (B) Preparation example B-1 (XDI-TMP) Takenate D-110N (product name, trimethylolpropane adduct of 1,3-xylylene diisocyanate (XDI-TMP), manufactured by Mitsui Chemicals) was prepared.

[0120] Preparation Example B-2 (XDI Isocyanurate) Takenate D-131N (product name, isocyanurate modified form of 1,3-xylylene diisocyanate (XDI isocyanurate), manufactured by Mitsui Chemicals) was prepared.

[0121] Preparation example B-3 (HDI-TMP) Takenate D-160N (product name, trimethylolpropane adduct of hexamethylene diisocyanate (HDI-TMP), manufactured by Mitsui Chemicals) was prepared.

[0122] Preparation example B-4 (PDI-TMP) A trimethylolpropane adduct of pentamethylene diisocyanate (PDI) (PDI-TMP) was prepared according to the description of Example 1 in Sections

[0101] to

[0103] of Japanese Patent Publication No. 2010-265364.

[0123] More specifically, 500 parts by mass of pentamethylene diisocyanate (PDI) and 50.0 parts by mass of trimethylolpropane (TMP) were charged into a four-necked flask equipped with a stirrer, thermometer, reflux tubing, and nitrogen inlet tube to obtain a mixture. The equivalent ratio of isocyanate groups of PDI to hydroxyl groups of TMP (isocyanate groups / hydroxyl groups) was 5.8. Next, the mixture was heated to 75°C to dissolve the trimethylolpropane. Subsequently, the mixture was reacted at 83°C until the concentration of unreacted isocyanate groups reached 41.0% by mass.

[0124] Next, the reaction solution was cooled to 55°C. Then, 350 parts by mass of a mixed extraction solvent (n-hexane / ethyl acetate = 90 / 10 (mass ratio)) was added to the reaction solution, stirred for 10 minutes, and allowed to stand for 10 minutes to remove the extraction solvent. This extraction procedure was repeated four times.

[0125] Subsequently, the reaction mixture was heated to 80°C under reduced pressure to remove any remaining extraction solvent. This yielded the PDI trimethylolpropane adduct. Solvent (ethyl acetate) was added to the PDI trimethylolpropane adduct to adjust the solid content to 75% by mass.

[0126] Preparation Example B-5 (PDI Isocyanurate) We prepared Stabio D-370N (product name, isocyanurate modified form of pentamethylene diisocyanate (PDI isocyanurate), manufactured by Mitsui Chemicals).

[0127] 3. Adhesive composition and adhesive Examples 1-13 and Comparative Examples 1-6 (1) Polyurethane polyol The raw material polyisocyanate (a2) and raw material polyol (a1) were combined according to the formulations described in Tables 1 and 2. These were mixed in the proportions shown in Tables 1 and 2, and then a urethane catalyst (dibutyltin dilaurate) was added. The amount of urethane catalyst was 100 ppm relative to the total amount of raw material polyisocyanate (a2), raw material polyol (a1), and urethane catalyst.

[0128] Furthermore, the proportion of hydroxyl groups derived from polyether polyol (a1-1) was 56.7 mol% and the proportion of hydroxyl groups derived from polyester polyol (a1-2) was 43.3 mol% relative to the total moles of hydroxyl groups derived from both polyether polyol (a1-1) and polyester polyol (a1-2). In addition, the equivalent ratio of isocyanate groups of raw material polyisocyanate (a2) to hydroxyl groups of raw material polyol (a1) (a2 / a1)(NCO / OH) was 0.74.

[0129] These mixtures were heated to 75°C and allowed to undergo a urethane reaction for 15 hours, and the disappearance of the isocyanate group was confirmed. This yielded polyurethane polyol (a) as the reaction product. Polyurethane polyol (a) was dissolved in ethyl acetate. This yielded a solution of polyurethane polyol (a) (solid content concentration 51% by mass).

[0130] In Comparative Example 6, acrylic polyol 6HY-3030 (trade name, number average molecular weight 600,000, manufactured by Taisei Fine Chemicals) was prepared instead of polyurethane polyol.

[0131] (2) Polyurethane adhesive composition A polyurethane adhesive composition (uncured resin composition) was prepared by combining a polyol component (A) and a polyisocyanate component (B) according to the formulations described in Tables 1 and 2. Then, the polyol component (A) and the polyisocyanate component (B) were mixed. The mixing ratio was adjusted so that the equivalent ratio (B / A) (NCO / OH) of the isocyanate groups of the polyisocyanate component (B) to the hydroxyl groups of the polyol component (A) was as shown in Tables 1 and 2. This resulted in obtaining a mixture of polyurethane adhesive compositions.

[0132] (3) Polyurethane adhesive A mixture of polyurethane adhesive compositions was applied to a polyethylene terephthalate (PET) film. The amount of polyurethane adhesive composition applied was adjusted so that the dry thickness of the coating film was 20 μm.

[0133] The polyurethane adhesive composition was then heated at 110°C for 2 minutes to react and cure. This cured the polyurethane adhesive composition, yielding a polyurethane adhesive. The polyurethane adhesive was covered with a release film and aged for 2 days in a constant temperature and humidity chamber at 23°C and 60% relative humidity.

[0134] 4. Evaluation (1)Water resistance The polyurethane adhesive was cut to a width of 25 mm. The release film was peeled off the polyurethane adhesive. The polyurethane adhesive was pressed onto a glass plate, and a 2 kg roller was rolled over the polyurethane adhesive once back and forth. This pressed the polyurethane adhesive and the glass plate together.

[0135] The polyurethane adhesive and glass plate were subjected to a water resistance test. Specifically, the polyurethane adhesive and glass plate were immersed in distilled water at 25°C for 24 hours.

[0136] Then, before and after the above water resistance test, the polyurethane adhesive and glass plate were peeled off using a tensile testing machine (tensile speed 300 mm / min, peel angle 180°). This allowed us to measure the adhesive strength of the polyurethane adhesive before and after the water resistance test. Subsequently, the adhesion retention rate after the water resistance test was calculated using the following formula.

[0137] Adhesion retention rate (%) = [Adhesion after water resistance test (N / 25mm) / Adhesion before water resistance test (N / 25mm)] × 100

[0138] Water resistance was evaluated according to the following criteria. The results are shown in Tables 1 and 2. ◎; Adhesion retention rate is over 90% but less than 110%. ○; Adhesion retention rate is over 80% but 90% or less, or 110% or more but less than 120%. △; Adhesion retention rate is over 70% but 80% or less, or 120% or more but less than 130%. ×; Adhesion retention rate is 70% or less, or 130% or more.

[0139] (2) Moisture and heat resistance The polyurethane adhesive was cut to a width of 25 mm. The release film was peeled off the polyurethane adhesive. The polyurethane adhesive was pressed onto a glass plate, and a 2 kg roller was rolled over the polyurethane adhesive once back and forth. This pressed the polyurethane adhesive and the glass plate together.

[0140] Polyurethane adhesive and glass plates were subjected to a humid heat resistance test. Specifically, the polyurethane adhesive and glass plates were left standing for two days in a humid heat constant temperature chamber at 60°C and 90% relative humidity. Subsequently, the polyurethane adhesive and polarizing plate were left standing for one hour in a room at 23°C and 50% relative humidity.

[0141] Then, before and after the above-mentioned humidity and heat resistance test, the polyurethane adhesive and glass plate were peeled off using a tensile testing machine (tensile speed 300 mm / min, peel angle 180°C). This allowed us to measure the adhesive strength of the polyurethane adhesive before and after the humidity and heat resistance test. Subsequently, the adhesion retention rate after the humidity and heat resistance test was calculated using the following formula.

[0142] Adhesion retention rate (%) = [Adhesion after humidity and heat resistance test (N / 25mm) / Adhesion before humidity and heat resistance test (N / 25mm)] × 100

[0143] The moisture and heat resistance was evaluated according to the following criteria. The results are shown in Tables 1 and 2. ◎; Adhesion retention rate is over 90% but less than 110%. ○; Adhesion retention rate is over 80% but 90% or less, or 110% or more but less than 120%. △; Adhesion retention rate is over 70% but 80% or less, or 120% or more but less than 130%. ×; Adhesion retention rate is 70% or less, or 130% or more.

[0144] (3) Stain resistance After the above humidity and heat resistance test, the polyurethane adhesive was peeled off the glass plate. The presence or absence of residual (adhered) polyurethane adhesive on the glass plate was then visually confirmed. In addition, the ratio of the area where residual (adhered) polyurethane adhesive was found to the total laminated area (adhered area) of the glass plate and polyurethane adhesive was confirmed.

[0145] The stain resistance was evaluated according to the following criteria. The results are shown in Tables 1 and 2. ◎; No traces of polyurethane adhesive peeling were found. Furthermore, no residual (adhered) polyurethane adhesive was found. ○; Traces of polyurethane adhesive peeling were observed. On the other hand, no residual (adhered) polyurethane adhesive was found. △; Residual (adhered) polyurethane adhesive was detected. The area where residual (adhered) polyurethane adhesive was detected was 50% or less of the total adhesive area on the glass plate. ×; Residual (adhered) polyurethane adhesive was detected. The area where residual (adhered) polyurethane adhesive was detected exceeded 50% of the adhesive surface area on the glass plate.

[0146] [Table 1]

[0147] [Table 2]

Claims

1. This is a polyurethane adhesive composition containing a polyol component (A) and a polyisocyanate component (B). The aforementioned polyol component (A) contains polyurethane polyol (a), The polyurethane polyol (a) is composed of a reaction product of raw material polyol (a1) and raw material polyisocyanate (a2). The aforementioned raw material polyol (a1) is A polyether polyol (a1-1) with a number average molecular weight of 1000 to 3000, Polyester polyols (a1-2) with a number average molecular weight of 500 to 900 and It consists of, or The aforementioned polyether polyol (a1-1) and, The aforementioned polyester polyol (a1-2) and, Other raw material polyols in an amount of 10% by mass or less relative to the total amount of the raw material polyol (a1) It consists of, A polyurethane adhesive composition in which, with respect to the total moles of hydroxyl groups derived from the polyether polyol (a1-1) and the polyester polyol (a1-2), the proportion of hydroxyl groups derived from the polyether polyol (a1-1) is 50 mol% or more and 60 mol% or less, and the proportion of hydroxyl groups derived from the polyester polyol (a1-2) is 40 mol% or more and 50 mol% or less.

2. The average number of hydroxyl groups in the aforementioned polyether polyol (a1-1) is 3. The polyurethane adhesive composition according to claim 1, wherein the average number of hydroxyl groups of the polyester polyol (a1-2) is 2.

3. The aforementioned polyester polyol (a1-2) contains a condensate of a low molecular weight polyol and a polybasic acid, The polyurethane adhesive composition according to claim 1, wherein the low molecular weight polyol contains neopentyl glycol.

4. A polyurethane adhesive formed from the polyurethane adhesive composition described in claim 1.

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