Two-component curable polyurethane adhesive composition, polyurethane adhesive, and main agent for two-component curable polyurethane adhesive composition

Abstract

This two-component curable polyurethane adhesive composition comprises a main agent (A) and a curing agent (B). The main agent (A) contains a polyurethane polyol. The polyurethane polyol contains a reaction product of a raw-material polyisocyanate and a raw-material polyol. The raw-material polyol contains a hydrophobic polyol containing 30-95 mass% of a hydrocarbon portion having 12-80 carbon atoms per molecule. The hydrophobic polyol contains castor oil and / or a dimer acid polyol. The content ratio of the hydrophobic polyol is 25-93 mass% with respect to the total amount of the raw-material polyisocyanate and the raw-material polyol.

Description

Two-component curing polyurethane adhesive composition, polyurethane adhesive, and base agent for two-component curing polyurethane adhesive composition

[0001] The present invention relates to a two-component curing polyurethane pressure-sensitive adhesive composition, a polyurethane pressure-sensitive adhesive, and a base agent for a two-component curing polyurethane pressure-sensitive adhesive composition.

[0002] Polyurethane adhesives are known in the art. The polyurethane adhesive is an adhesive containing a polyurethane resin. The adhesive is, for example, a cured resin having a relatively low glass transition temperature and adhesive properties (pressure-sensitive adhesiveness, tackiness).

[0003] The polyurethane adhesive is, for example, a reaction product of a two-component curing polyurethane adhesive composition. More specifically, the two-component curing polyurethane adhesive composition includes, for example, a base agent containing polyurethane polyol and a curing agent containing polyisocyanate. The base agent and the curing agent are mixed and reacted to obtain the polyurethane adhesive.

[0004] For example, the following adhesive layer has been proposed as a polyurethane adhesive. That is, the adhesive layer is obtained by reacting a urethane polyol (A) with an isocyanate curing agent (B). The urethane polyol (A) is, for example, a reaction product of a hydroxyl-terminated liquid polybutadiene, a polyether polyol, and hexamethylene diisocyanate. For example, a trimethylolpropane adduct of hexamethylene diisocyanate is used as the isocyanate curing agent (B) (see, for example, Patent Document 1 (Synthesis Example 34 and Example 66)).

[0005] Japanese Patent Application Laid-Open No. 2020-059860

[0006] On the other hand, polyurethane adhesives are required to have excellent stain resistance, more specifically, to reduce adhesive residue when peeled off, and to have excellent water resistance.

[0007] The present invention provides a two-component curing polyurethane pressure-sensitive adhesive composition, a polyurethane pressure-sensitive adhesive, and a base agent for a two-component curing polyurethane pressure-sensitive adhesive composition that can relatively reduce adhesive residue and have relatively excellent water resistance.

[0008] The present invention [1] is a two-component curing polyurethane pressure-sensitive adhesive composition comprising a main component (A) and a curing agent (B), wherein the main component (A) contains a polyurethane polyol, the polyurethane polyol containing a reaction product of a raw polyisocyanate and a raw polyol, the raw polyol containing a hydrophobic polyol having a hydrocarbon moiety having from 12 to 80 carbon atoms in its molecule in a proportion of from 30 to 95 mass%, the hydrophobic polyol containing castor oil and / or a dimer acid polyol, and the proportion of the hydrophobic polyol is from 25 to 93 mass%, based on the total amount of the raw polyisocyanate and the raw polyol.

[0009] The present invention [2] comprises the two-component curing polyurethane pressure-sensitive adhesive composition according to the above [1], wherein the hydrophobic polyol contains a castor oil and a dimer acid polyol, and the castor oil content is 0.5 parts by mass or more per 1 part by mass of the dimer acid polyol.

[0010] The present invention [3] includes the two-component curing polyurethane pressure-sensitive adhesive composition according to the above [1] or [2], wherein the raw material polyol further contains a polyether polyol.

[0011] The present invention [4] comprises the two-component curing polyurethane pressure-sensitive adhesive composition according to any one of the above [1] to [3], wherein the raw material polyisocyanate contains a chain aliphatic polyisocyanate monomer.

[0012] The present invention [5] includes the two-component curing polyurethane pressure-sensitive adhesive composition according to any one of the above [1] to [4], wherein the curing agent (B) contains an alicyclic polyisocyanate derivative.

[0013] The present invention [6] includes the two-component curing polyurethane pressure-sensitive adhesive composition according to any one of the above [1] to [4], wherein the curing agent (B) contains a chain aliphatic polyisocyanate derivative.

[0014] The present invention [7] includes the two-component curing polyurethane pressure-sensitive adhesive composition according to any one of the above [1] to [6], wherein the curing agent (B) contains a derivative of pentamethylene diisocyanate.

[0015] The present invention [8] includes a polyurethane pressure-sensitive adhesive formed from the two-component curing polyurethane pressure-sensitive adhesive composition according to any one of the above [1] to [7], and containing a reaction-cured product of the main component (A) and the main component (B).

[0016] The present invention [9] is a base for a two-component curing polyurethane pressure-sensitive adhesive composition, the base comprising a polyurethane polyol, the polyurethane polyol comprising a reaction product of a raw material polyisocyanate and a raw material polyol, the raw material polyol comprising a hydrophobic polyol containing hydrocarbon moieties having from 12 to 80 carbon atoms in the molecule in a proportion of from 30 to 95 mass%, the hydrophobic polyol comprising castor oil and / or a dimer acid polyol, the proportion of the hydrophobic polyol being from 25 to 93 mass%, based on the total amount of the raw material polyisocyanate and the raw material polyol.

[0017] The present invention

[10] comprises the base for a two-component curing polyurethane pressure-sensitive adhesive composition according to the above [9], in which the castor oil content is 0.5 parts by mass or more per 1 part by mass of the dimer acid polyol.

[0018] The two-component curing polyurethane pressure-sensitive adhesive composition of the present invention contains a base agent (A) and a curing agent (B). The base agent (A) contains a polyurethane polyol. The polyurethane polyol contains a reaction product of a raw material polyisocyanate and a raw material polyol. The raw material polyol also contains a hydrophobic polyol, and the hydrophobic polyol contains castor oil and / or a dimer acid polyol. The hydrophobic polyol also contains hydrocarbon moieties having from 12 to 80 carbon atoms in its molecule in a proportion of from 30% by mass to 95% by mass. The content of the hydrophobic polyol is within a predetermined range.

[0019] The two-component curing polyurethane adhesive composition described above can relatively reduce adhesive residue upon peeling and can provide a polyurethane adhesive having relatively excellent water resistance.

[0020] The polyurethane pressure-sensitive adhesive of the present invention is obtained from the two-component curing polyurethane pressure-sensitive adhesive composition described above. Therefore, the polyurethane pressure-sensitive adhesive can relatively reduce adhesive residue upon peeling and has relatively excellent water resistance.

[0021] Furthermore, the base agent for the two-component curing polyurethane pressure-sensitive adhesive composition of the present invention can relatively reduce adhesive residue upon peeling, and can provide a polyurethane pressure-sensitive adhesive having relatively excellent water resistance.

[0022] 1. Two-component curing polyurethane adhesive composition A two-component curing polyurethane adhesive composition comprises a base component (A) and a curing agent (B). That is, a two-component curing polyurethane adhesive composition is a resin kit. The base component (A) and the curing agent (B) are, for example, prepared separately and mixed together at the time of use. Below, the base component (A) and the curing agent (B) are each described in detail.

[0023] [1] Main component (A) The main component (A) is a main component for a two-component curing polyurethane pressure-sensitive adhesive composition. The main component (A) contains a polyurethane polyol as an essential component. The main component (A) is preferably composed of a polyurethane polyol.

[0024] [1-1] Polyurethane polyol The polyurethane polyol contains a reaction product of a raw material polyisocyanate and a raw material polyol. Preferably, the polyurethane polyol is a reaction product of a raw material polyisocyanate and a raw material polyol. The raw material polyisocyanate and the raw material polyol are described in detail below.

[0025] (1) Raw Polyisocyanate Examples of the raw polyisocyanate include polyisocyanate compounds, such as linear aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and araliphatic polyisocyanates.

[0026] Examples of the chain aliphatic polyisocyanate include chain aliphatic polyisocyanate monomers and chain aliphatic polyisocyanate derivatives. Examples of the chain aliphatic polyisocyanate monomer include chain aliphatic diisocyanates. Examples of the chain aliphatic diisocyanates include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), and hexamethylene diisocyanate (HDI). These can be used alone or in combination of two or more. Examples of the chain aliphatic polyisocyanate derivative include modified chain aliphatic polyisocyanate monomers. Examples of the modified products include uretdione modified products, isocyanurate modified products, allophanate modified products, polyol modified products, biuret modified products, urea modified products, oxadiazinetrione modified products, and carbodiimide modified products. These can be used alone or in combination of two or more.

[0027] Examples of the alicyclic polyisocyanate include alicyclic polyisocyanate monomers and alicyclic polyisocyanate derivatives. Examples of the alicyclic polyisocyanate monomer include alicyclic diisocyanates. Examples of the alicyclic diisocyanates include cyclohexane diisocyanate, bis(isocyanatomethyl)cyclohexane (H ６XDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), and methylenebis(cyclohexyl isocyanate) (H １２ Examples of the alicyclic polyisocyanate derivative include the above-mentioned modified products of the alicyclic polyisocyanate monomer. These can be used alone or in combination of two or more kinds.

[0028] Examples of aromatic polyisocyanates include aromatic polyisocyanate monomers and aromatic polyisocyanate derivatives. Examples of aromatic polyisocyanate monomers include aromatic diisocyanates. Examples of aromatic diisocyanates include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), toluidine diisocyanate (TODI), paraphenylene diisocyanate, and naphthalene diisocyanate (NDI). Examples of aromatic polyisocyanate derivatives include the above-mentioned modified products of aromatic polyisocyanate monomers. These can be used alone or in combination of two or more types.

[0029] Examples of araliphatic polyisocyanates include araliphatic polyisocyanate monomers and araliphatic polyisocyanate derivatives. Examples of araliphatic polyisocyanate monomers include araliphatic diisocyanates. Examples of araliphatic diisocyanates include xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI). Examples of araliphatic polyisocyanate derivatives include the above-mentioned modified araliphatic polyisocyanate monomers. These can be used alone or in combination of two or more types.

[0030] The polyisocyanate compound can be used alone or in combination of two or more kinds. From the viewpoint of water resistance and stain resistance (suppression of adhesive residue (the same applies below)), the polyisocyanate compound is preferably a chain aliphatic polyisocyanate, more preferably a chain aliphatic polyisocyanate monomer, even more preferably a chain aliphatic diisocyanate, and even more preferably pentamethylene diisocyanate (PDI) and hexamethylene diisocyanate (HDI). From the viewpoint of easy availability, hexamethylene diisocyanate (HDI) is particularly preferred.

[0031] That is, from the viewpoint of water resistance and stain resistance, the raw material polyisocyanate preferably contains a chain aliphatic polyisocyanate, more preferably contains a chain aliphatic polyisocyanate monomer, even more preferably contains a chain aliphatic polyisocyanate monomer, even more preferably contains a chain aliphatic diisocyanate, and even more preferably contains pentamethylene diisocyanate (PDI) and / or hexamethylene diisocyanate (HDI). From the viewpoint of easy availability, the raw material polyisocyanate particularly preferably contains hexamethylene diisocyanate (HDI).

[0032] The raw material polyisocyanate preferably comprises a chain aliphatic polyisocyanate, more preferably a chain aliphatic polyisocyanate monomer, even more preferably a chain aliphatic polyisocyanate monomer, even more preferably a chain aliphatic diisocyanate, and even more preferably pentamethylene diisocyanate (PDI) and / or hexamethylene diisocyanate (HDI). From the viewpoint of availability, the raw material polyisocyanate is particularly preferably hexamethylene diisocyanate (HDI).

[0033] In the raw material polyisocyanate, the average number of isocyanate groups in the polyisocyanate compound is, for example, 2 or more and 6 or less, preferably 2 or more and 4 or less, more preferably 2 or more and 3 or less, and particularly preferably 2.

[0034] (2) Raw Material Polyol (2-1) Hydrophobic Polyol The raw material polyol contains a hydrophobic polyol as an essential component. The hydrophobic polyol is a polyol containing hydrocarbon moieties having from 12 to 80 carbon atoms in the molecule in a proportion of from 30% by mass to 95% by mass.

[0035] More specifically, the number of carbon atoms in the hydrocarbon portion of the hydrophobic polyol is from 12 to 80, preferably from 18 to 60, and more preferably from 22 to 40. The content of the hydrocarbon portion is from 30 to 95% by mass, preferably from 40 to 90% by mass, based on the total amount of the hydrophobic polyol.

[0036] The number average molecular weight of the hydrophobic polyol (molecular weight calculated as standard polystyrene by gel permeation chromatography) is not particularly limited, but is, for example, more than 400 and not more than 5000, preferably from 500 to 3000. The average number of hydroxyl groups of the hydrophobic polyol is not particularly limited, but is, for example, from 2 to 6, preferably from 2 to 4.

[0037] Examples of the hydrophobic polyol include a hydrophobic polyol derived from animals and plants and a hydrophobic polyol derived from petroleum. From the viewpoint of environmental friendliness, the hydrophobic polyol contains a hydrophobic polyol derived from animals and plants as an essential component, and preferably consists of a hydrophobic polyol derived from animals and plants.

[0038] (2-1-1) Animal- or Plant-Derived Hydrophobic Polyol The animal- or plant-derived hydrophobic polyol contains, as an essential component, a castor oil and / or a dimer acid polyol. That is, in the raw material polyol, the hydrophobic polyol contains, as an essential component, a castor oil and / or a dimer acid polyol.

[0039] Examples of castor oils include castor oil and hydrogenated castor oil.

[0040] Castor oil is a glyceride of fatty acids, primarily ricinoleic acid. More specifically, castor oil is a glyceride of unsaturated fatty acids, including, for example, ricinoleic acid, oleic acid, and linoleic acid, and saturated fatty acids, including palmitic acid and stearic acid.

[0041] In castor oil, the content of ricinoleic acid is, for example, 87% by mass or more and 90% by mass or less, the content of oleic acid is, for example, 2.5% by mass or more and 4% by mass or less, the content of linoleic acid is, for example, 4% by mass or more and 5% by mass or less, the content of palmitic acid is, for example, 0.5% by mass or more and 1.5% by mass or less, and the content of stearic acid is, for example, 0.5% by mass or more and 1.5% by mass or less.

[0042] Examples of castor oil include commercially available products. Examples of commercially available products include deodorized refined castor oil (manufactured by Toyokuni Oil Mills), refined castor oil (manufactured by Toyokuni Oil Mills), ELA-DR (manufactured by Toyokuni Oil Mills), industrial No. 1 castor oil (manufactured by Toyokuni Oil Mills), refined castor oil special A (Marutoku A) (manufactured by Ito Oil Mills), refined castor oil special A (Kakutoku A) (manufactured by Ito Oil Mills), refined castor oil special A (Dia) (manufactured by Ito Oil Mills), refined castor oil technical 1 (Kakukoichi) (manufactured by Ito Oil Mills), refined castor oil technical 1 (Koichi) (manufactured by Ito Oil Mills), FS CASTOR OIL (manufactured by ROYAL CASTOR PRODUCTS), and COLD PRESS CASTOR OIL (manufactured by ROYAL CASTOR PRODUCTS). These can be used alone or in combination of two or more.

[0043] Hydrogenated castor oil is a hydrogenated product of the above-mentioned castor oil in which the unsaturated groups are hydrogenated. Hydrogenated castor oil can be obtained by hydrogenating castor oil by a known method.

[0044] Examples of hydrogenated castor oil include commercially available products such as HYDROGENATED CASTOR OIL (manufactured by ROYAL CASTOR PRODUCTS), hydrogenated castor oil (manufactured by Toyokuni Oil Mills), hydrogenated castor oil A (manufactured by Ito Oil Mills), and hydrogenated castor oil (manufactured by Ito Oil Mills). These can be used alone or in combination of two or more types.

[0045] The castor oils preferably include castor oil (non-hydrogenated castor oil). That is, the castor oils preferably contain castor oil, and more preferably consist of castor oil.

[0046] The number average molecular weight (molecular weight calculated as standard polystyrene by gel permeation chromatography) of castor oils is not particularly limited, but is, for example, more than 400 and not more than 5000, preferably from 500 to 3000. The average number of hydroxyl groups of castor oils is not particularly limited, but is, for example, from 2.5 to 6, preferably from 2.5 to 3.5.

[0047] Examples of dimer acid polyols include dimer acid ester-containing polyester polyols.

[0048] The dimer acid ester-containing polyester polyol can be obtained, for example, by esterifying a polybasic acid including a dimer acid and / or its alkyl ester with a low-molecular-weight polyol.

[0049] Examples of dimer acids include dimer acid and hydrogenated dimer acid. Dimer acid contains a plant-derived fatty acid, more specifically, a dimer of a plant-derived unsaturated fatty acid having 18 carbon atoms. Dimer acid is preferably a dimer of a plant-derived unsaturated fatty acid having 18 carbon atoms. Hydrogenated dimer acid is a hydrogenation product obtained by hydrogenating the unsaturated group of dimer acid. Hydrogenated dimer acid can be obtained by hydrogenating dimer acid using a known method. Dimer acids can contain monomer acid and / or trimer acid as impurities. The content ratio of monomer acid and / or trimer acid can be appropriately set within a range that does not impair the excellent effects of the present invention.

[0050] As the dimer acid, preferably, a dimer acid (non-hydrogenated dimer acid) is used. Dimer acids are available, for example, as industrial raw materials.

[0051] Dimer acids are used in combination with other polybasic acids as needed. The other polybasic acids are polybasic acids other than dimer acids. Examples of other polybasic 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, sebacic acid, other aliphatic dicarboxylic acids (C11 to C13), maleic acid, fumaric acid, itaconic acid, orthophthalic acid, isophthalic acid, terephthalic acid, toluenedicarboxylic acid, HET acid, and acid anhydrides thereof. These can be used alone or in combination of two or more.

[0052] The alkyl ester is not particularly limited, and examples thereof include alkyl esters having an alkyl group having 1 to 20 carbon atoms.

[0053] The low-molecular-weight polyol is an organic compound having two or more hydroxyl groups in the molecule and a relatively low molecular weight. The number average molecular weight of the low-molecular-weight polyol is, for example, 40 or more and 400 or less.

[0054] Examples of low-molecular-weight polyols include known polyhydric alcohols. Examples of polyhydric alcohols 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, 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 alone or in combination of two or more.

[0055] The method for esterifying a polybasic acid containing a dimer acid and / or its alkyl ester with a low-molecular-weight polyol is not particularly limited. For example, a dimer acid ester-containing polyester polyol can be obtained by dehydration condensation of a polybasic acid containing a dimer acid with a low-molecular-weight polyol using a known method. Alternatively, a dimer acid ester-containing polyester polyol can be obtained by transesterification of an alkyl ester of a polybasic acid containing a dimer acid with a low-molecular-weight polyol using a known method.

[0056] Examples of dimer acid polyols include commercially available products, such as PRIPLAST3238-LQ-(GD) (manufactured by CRODA). These can be used alone or in combination of two or more types.

[0057] The number average molecular weight (molecular weight in terms of standard polystyrene measured by gel permeation chromatography) of the dimer acid polyol is not particularly limited, but is, for example, more than 400 and not more than 5,000, preferably from 500 to 2,000. The average number of hydroxyl groups of the dimer acid polyol is not particularly limited, but is, for example, from 2 to 6, preferably from 2 to 4.

[0058] In the hydrophobic polyol, the content ratio of the castor oil and the content ratio of the dimer acid polyol are appropriately set according to the purpose and use. For example, the castor oil may be used alone. Alternatively, the dimer acid polyol may be used alone. Alternatively, the castor oil and the dimer acid polyol may be used in combination.

[0059] From the viewpoint of water resistance and stain resistance, it is preferable to use a castor oil and a dimer acid polyol in combination. That is, from the viewpoint of water resistance and stain resistance, it is preferable that the hydrophobic polyol contains a castor oil and a dimer acid polyol.

[0060] When castor oils and dimer acid polyols are used in combination, from the viewpoint of contamination resistance, the content of the castor oils is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.55 parts by mass or more, relative to 1 part by mass of the dimer acid polyol. Also, the content of the castor oils is, for example, 10.0 parts by mass or less, preferably 7.0 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 3.0 parts by mass or less, relative to 1 part by mass of the dimer acid polyol.

[0061] That is, from the viewpoint of contamination resistance, the content of castor oils relative to 1 part by mass of dimer acid polyol is, for example, 0.01 parts by mass or more and 10.0 parts by mass or less, preferably 0.1 parts by mass or more and 7.0 parts by mass or less, more preferably 0.5 parts by mass or more and 5.0 parts by mass or less, and even more preferably 0.55 parts by mass or more and 3.0 parts by mass or less.

[0062] When castor oils and dimer acid polyols are used in combination, from the viewpoint of contamination resistance, the content of castor oils relative to the total amount of castor oils and dimer acid polyols is, for example, 1% by mass or more, preferably 10% by mass or more, more preferably 30% by mass or more. Furthermore, the content of castor oils relative to the total amount of castor oils and dimer acid polyols is, for example, 99% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less. That is, the content of castor oils relative to the total amount of castor oils and dimer acid polyols is, for example, 1% by mass or more and 99% by mass or less, preferably 10% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less.

[0063] In other words, the content of the dimer acid polyol relative to the total amount of the castor oils and the dimer acid polyol is, for example, 1% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more. Also, the content of the dimer acid polyol relative to the total amount of the castor oils and the dimer acid polyol is, for example, 99% by mass or less, preferably 90% by mass or less, more preferably 70% by mass or less. That is, the content of the dimer acid polyol relative to the total amount of the castor oils and the dimer acid polyol is, for example, 10% by mass or more and 99% by mass or less, preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 70% by mass or less.

[0064] (2-1-2) Petroleum-derived hydrophobic polyol The hydrophobic polyol may contain a petroleum-derived hydrophobic polyol as an optional component. That is, the raw material polyol may contain a petroleum-derived hydrophobic polyol as an optional component.

[0065] Examples of hydrophobic polyols derived from petroleum include polyolefin polyols. In other words, the raw material polyol can contain polyolefin polyol as an optional component.

[0066] Examples of polyolefin polyols include butadiene polyols (polybutadiene polyols) and partially saponified ethylene-vinyl acetate copolymers. These can be used alone or in combination of two or more.

[0067] The number average molecular weight (molecular weight calculated as standard polystyrene by gel permeation chromatography) of the polyolefin polyol is not particularly limited, but is, for example, 400 to 5000, preferably 500 to 2000. The average number of hydroxyl groups of the polyolefin polyol is not particularly limited, but is, for example, 2 to 6, preferably 2 to 4.

[0068] (2-1-3) Mass Proportion of Hydrophobic Polyol The content ratio of the hydrophobic polyol derived from animals and plants and the content ratio of the hydrophobic polyol derived from petroleum are appropriately set within a range that does not impair the excellent effects of the present invention.

[0069] From the viewpoint of water resistance and contamination resistance, the content of the animal- or plant-derived hydrophobic polyol is, for example, 70 mass % or more, preferably 80 mass % or more, more preferably 90 mass % or more, and particularly preferably 100 mass % relative to the total amount of hydrophobic polyols. In other words, the hydrophobic polyol preferably consists of an animal- or plant-derived hydrophobic polyol.

[0070] More specifically, from the viewpoint of water resistance and stain resistance, the content of castor oils and / or dimer acid polyols (total content when used in combination) is, for example, 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the total amount of hydrophobic polyols. In other words, the hydrophobic polyol is preferably composed of castor oils and / or dimer acid polyols, and more preferably composed of castor oils and dimer acid polyols.

[0071] In other words, from the viewpoint of water resistance and contamination resistance, the content of the petroleum-derived hydrophobic polyol is, for example, 30 mass% or less, preferably 20 mass% or less, more preferably 10 mass% or less, and particularly preferably 0 mass% relative to the total amount of hydrophobic polyols. In other words, from the viewpoint of water resistance and contamination resistance, the hydrophobic polyol preferably does not contain a petroleum-derived hydrophobic polyol.

[0072] (2-2) Other Polyols The raw material polyol can contain other polyols (i.e., polyols other than hydrophobic polyols) as optional components. That is, as the raw material polyol, a hydrophobic polyol may be used alone, or a hydrophobic polyol may be used in combination with another polyol.

[0073] From the viewpoint of water resistance and stain resistance, it is preferable to use a hydrophobic polyol and another polyol in combination. That is, from the viewpoint of water resistance and stain resistance, it is preferable that the raw material polyol contains a hydrophobic polyol and another polyol.

[0074] The other polyol is a polyol other than the above-mentioned hydrophobic polyol. The other polyol is, for example, a non-hydrophobic polyol. More specifically, the other polyol includes, for example, a low-molecular-weight polyol and a high-molecular-weight polyol (excluding the hydrophobic polyol).

[0075] (2-2-1) Low-Molecular-Weight Polyols Examples of low-molecular-weight polyols include the low-molecular-weight polyols described above as raw materials for dimer acid polyols. More specifically, examples include the dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. These can be used alone or in combination of two or more. In other polyols, the content of the low-molecular-weight polyol is appropriately set within a range that does not impair the excellent effects of the present invention.

[0076] (2-2-2) High Molecular Weight Polyol A high molecular weight polyol is an organic compound having two or more hydroxyl groups in the molecule and a relatively high molecular weight. The number average molecular weight of a high molecular weight polyol is, for example, more than 400 and not more than 20,000. The number average molecular weight can be calculated by a known method from the hydroxyl group equivalent weight and the average number of hydroxyl groups. The number average molecular weight can also be measured as a polystyrene-equivalent molecular weight by gel permeation chromatography (the same applies hereinafter).

[0077] More specifically, the number average molecular weight of the high molecular weight polyol is, for example, more than 400 and 20,000 or less, preferably 500 or more and 15,000 or less, more preferably 1,000 or more and 10,000 or less, even more preferably 1,500 or more and 7,000 or less, and particularly preferably 4,000 or more and 6,000 or less.

[0078] The average number of hydroxyl groups in the high molecular weight polyol is, for example, 2 or more and 6 or less, preferably 2.5 or more and 4 or less, and more preferably 2 or more and 3 or less.

[0079] More specifically, examples of high molecular weight polyols (excluding hydrophobic polyols) include polyether polyols, polyester polyols, and polycarbonate polyols. These may be used alone or in combination of two or more. Preferred examples of high molecular weight polyols include polyether polyols (excluding hydrophobic polyols) and polyester polyols (excluding hydrophobic polyols).

[0080] Examples of polyether polyols (excluding hydrophobic polyols) include polyoxyalkylene (C2-3) polyols and polytetramethylene ether polyols. Examples of polyoxyalkylene (C2-3) polyols include polyoxyethylene polyols, polyoxypropylene polyols, polyoxytriethylene polyols, and polyoxyethylene-polyoxypropylene polyols (random or block copolymers). Examples of polytetramethylene ether polyols include crystalline polytetramethylene ether glycol and amorphous polytetramethylene ether glycol. These can be used alone or in combination of two or more types.

[0081] From the viewpoint of water resistance and stain resistance, the number average molecular weight of the polyether polyol is, for example, more than 400 and 20,000 or less, preferably 500 or more and 15,000 or less, more preferably 1,000 or more and 10,000 or less, even more preferably 2,000 or more and 8,000 or less, and particularly preferably 3,000 or more and 5,000 or less.

[0082] In terms of water resistance and stain resistance, the average number of hydroxyl groups in the polyester polyol is, for example, 2 or more and 6 or less, preferably 3 or more and 5 or less, more preferably 3 or more and 4 or less, and particularly preferably 3.

[0083] Examples of polyester polyols (excluding hydrophobic polyols) include condensation polyester polyols and ring-opening polyester polyols. Examples of condensation polyester polyols include adipate-based condensation polyester polyols (e.g., polybutylene adipate) and phthalic acid-based condensation polyester polyols. Examples of ring-opening polyester polyols include lactone-based polyester polyols, more specifically, polycaprolactone polyols. These can be used alone or in combination of two or more types.

[0084] From the viewpoint of water resistance and stain resistance, the number average molecular weight of the polyester polyol is, for example, more than 400 and 20,000 or less, preferably 500 or more and 15,000 or less, more preferably 1,000 or more and 10,000 or less, even more preferably 1,200 or more and 5,000 or less, and particularly preferably 1,500 or more and 3,000 or less.

[0085] In terms of water resistance and stain resistance, the polyester polyol has an average number of hydroxyl groups of, for example, 2 or more and 6 or less, preferably 2 or more and 4 or less, more preferably 2 or more and 3 or less, and particularly preferably 2.

[0086] The other polyols can be used alone or in combination of two or more. As the other polyols, preferably, a high molecular weight polyol is used, more preferably, a polyether polyol is used, still more preferably, a polyoxyalkylene (C2-3) polyol is used, and particularly preferably, a polyoxypropylene polyol is used.

[0087] That is, the raw material polyol contains, for example, other polyols (polyols excluding hydrophobic polyols), preferably contains a high-molecular-weight polyol, more preferably contains a polyether polyol, even more preferably contains a polyoxyalkylene (C2-3) polyol, and particularly preferably contains a polyoxypropylene polyol.

[0088] (2-3) Ratio of Hydrophobic Polyol to Other Polyol When a hydrophobic polyol and another polyol are used in combination, the ratio of these contents is appropriately set depending on the purpose and application.

[0089] More specifically, when a hydrophobic polyol and another polyol are used in combination, from the viewpoint of contamination resistance, the content of the hydrophobic polyol relative to the total amount of the hydrophobic polyol and the other polyol (i.e., the total amount of raw material polyols (the same applies hereinafter)) is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 30% by mass or more. Furthermore, the content of the hydrophobic polyol relative to the total amount of the hydrophobic polyol and the other polyol is, for example, 90% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less. That is, the content of the hydrophobic polyol relative to the total amount of the hydrophobic polyol and the other polyol is, for example, 5% by mass or more and 90% by mass or less, preferably 10% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 75% by mass or less.

[0090] In other words, the content of the other polyol relative to the total amount of the hydrophobic polyol and the other polyol is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 25% by mass or more. Furthermore, the content of the other polyol relative to the total amount of the hydrophobic polyol and the other polyol is, for example, 95% by mass or less, preferably 90% by mass or less, more preferably 70% by mass or less. That is, the content of the other polyol relative to the total amount of the hydrophobic polyol and the other polyol is, for example, 10% by mass or more and 95% by mass or less, preferably 20% by mass or more and 90% by mass or less, more preferably 25% by mass or more and 70% by mass or less.

[0091] (3) Method for Producing Polyurethane Polyol The method for producing polyurethane polyol is not particularly limited. For example, raw material polyisocyanate and raw material polyol are mixed in a predetermined ratio and subjected to a urethane reaction.

[0092] (3-1) Equivalent Ratio In the production of polyurethane polyol, the blending ratio of the raw material polyisocyanate and the raw material polyol is adjusted, for example, based on the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the raw material polyisocyanate to the hydroxyl group in the raw material polyol.

[0093] More specifically, the equivalent ratio of the isocyanate groups in the raw polyisocyanate to the hydroxyl groups in the raw polyol (isocyanate groups / hydroxyl groups) is, for example, less than 1.0, preferably 0.5 or more and 0.9 or less, and more preferably 0.6 or more and 0.85 or less.

[0094] (3-2) Mass Ratio In the production of polyurethane polyol, the blending ratio of the raw material polyisocyanate to the raw material polyol is adjusted based on the mass ratio (mass proportion) of the hydrophobic polyol.

[0095] (3-2-1) Mass Proportion of Hydrophobic Polyol From the viewpoint of water resistance and contamination resistance, the content of the hydrophobic polyol is 25% by mass or more, preferably 28% by mass or more, more preferably 30% by mass or more, even more preferably 33% by mass or more, and particularly preferably 35% by mass or more, based on the total amount of the raw material polyisocyanate and raw material polyol.

[0096] Furthermore, from the viewpoint of water resistance and contamination resistance, the content of the hydrophobic polyol is 93% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, and particularly preferably 70% by mass or less, based on the total amount of the raw material polyisocyanate and raw material polyol.

[0097] That is, from the viewpoint of water resistance and contamination resistance, the content of the hydrophobic polyol is 25% by mass or more and 93% by mass or less, preferably 28% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less, even more preferably 33% by mass or more and 75% by mass or less, and particularly preferably 35% by mass or more and 70% by mass or less, based on the total amount of the raw material polyisocyanate and raw material polyol.

[0098] (3-2-2) Mass Proportion of Other Polyols The content of other polyols (i.e., polyols excluding hydrophobic polyols (the same applies hereinafter)) is, from the viewpoint of water resistance and contamination resistance, for example, 0 mass % or more, preferably 1 mass % or more, more preferably 10 mass % or more, even more preferably 20 mass % or more, and particularly preferably 25 mass % or more, based on the total amount of the raw material polyisocyanate and the raw material polyol.

[0099] Furthermore, from the viewpoint of water resistance and contamination resistance, the content of the other polyol is, for example, 74% by mass or less, preferably 70% by mass or less, more preferably 68% by mass or less, even more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less, based on the total amount of the raw material polyisocyanate and raw material polyol.

[0100] That is, from the viewpoint of water resistance and contamination resistance, the content of the other polyol relative to the total amount of the raw material polyisocyanate and raw material polyol is, for example, 0% by mass or more and 74% by mass or less, preferably 1% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 68% by mass or less, even more preferably 20% by mass or more and 65% by mass or less, and particularly preferably 25% by mass or more and 60% by mass or less.

[0101] (3-2-3) Mass Proportion of Raw Material Polyol The content of the raw material polyol (i.e., the sum of the content of the hydrophobic polyol and the content of the other polyol (the same applies hereinafter)) is, for example, 80 mass % or more, preferably 85 mass % or more, and more preferably 90 mass % or more, based on the total amount of the raw material polyisocyanate and the raw material polyol.

[0102] The content of the raw material polyol relative to the total amount of the raw material polyisocyanate and raw material polyol is, for example, 99 mass % or less, preferably 97 mass % or less, and more preferably 95 mass % or less.

[0103] That is, the content of the raw material polyol relative to the total amount of the raw material polyisocyanate and the raw material polyol is, for example, 80% by mass or more and 99% by mass or less, preferably 85% by mass or more and 97% by mass or less, and more preferably 90% by mass or more and 95% by mass or less.

[0104] (3-2-4) Mass Proportion of Raw Material Polyisocyanate The content of the raw material polyisocyanate relative to the total amount of the raw material polyisocyanate and the raw material polyol is, for example, 1 mass% or more, preferably 3 mass% or more, and more preferably 5 mass% or more.

[0105] The content of the raw polyisocyanate relative to the total amount of the raw polyisocyanate and the raw polyol is, for example, 20 mass % or less, preferably 15 mass % or less, and more preferably 10 mass % or less.

[0106] That is, the content of the raw material polyisocyanate relative to the total amount of the raw material polyisocyanate and the raw material polyol is, for example, 1% by mass or more and 20% by mass or less, preferably 3% by mass or more and 15% by mass or less, and more preferably 5% by mass or more and 10% by mass or less.

[0107] (3-3) Reaction Conditions The reaction conditions for the raw material polyisocyanate and raw material polyol are not particularly limited. The reaction temperature is, for example, 40°C or higher and 100°C or lower. The reaction time is, for example, 1 hour or higher and 24 hours or lower. The atmospheric conditions are, for example, an inert gas atmosphere, specifically, for example, a nitrogen atmosphere or an argon atmosphere.

[0108] In the reaction between the raw material polyisocyanate and the raw material polyol, a urethanization catalyst is blended as necessary. Examples of the urethanization catalyst include known amines, known organometallic compounds, and known potassium salts. These can be used alone or in combination of two or more. A preferred example of the urethanization catalyst is an organometallic compound. The blending ratio of the urethanization catalyst is not particularly limited and can be appropriately set depending on the purpose and application.

[0109] The reaction between the raw polyisocyanate and the raw polyol may be, for example, bulk polymerization or solution polymerization. In other words, an organic solvent may be added to the reaction between the raw polyisocyanate and the raw polyol, if necessary.

[0110] The organic solvent is not particularly limited, and known organic solvents can be used. More specifically, examples of the organic solvent include ketones, nitriles, alkyl esters (e.g., ethyl acetate), aliphatic hydrocarbons, aromatic hydrocarbons, glycol ether esters, ethers, halogenated aliphatic hydrocarbons, and polar aprotic solvents. These can be used alone or in combination of two or more. The blending ratio of the organic solvent is not particularly limited, and can be appropriately set depending on the purpose and application.

[0111] Then, a polyurethane polyol is produced by the reaction between the raw polyisocyanate and the raw polyol. When the raw polyisocyanate and the raw polyol are solution polymerized, a solution of polyurethane polyol is obtained by the above reaction.

[0112] (4) Physical Properties of Polyurethane Polyol Polyurethane polyol contains, as an essential structural unit, a structural unit derived from the hydrophobic polyol. The content ratio of the structural unit derived from the hydrophobic polyol in the polyurethane polyol is, for example, the same as the content ratio of the hydrophobic polyol relative to the total amount of the raw material polyisocyanate and the raw material polyol.

[0113] More specifically, from the viewpoint of water resistance and stain resistance, the content of structural units derived from hydrophobic polyol is, for example, 25 mass% or more, preferably 28 mass% or more, more preferably 30 mass% or more, even more preferably 33 mass% or more, and particularly preferably 35 mass% or more, relative to the total amount of polyurethane polyol.

[0114] From the viewpoint of water resistance and stain resistance, the content of structural units derived from hydrophobic polyol is, for example, 93 mass% or less, preferably 90 mass% or less, more preferably 80 mass% or less, even more preferably 75 mass% or less, and particularly preferably 70 mass% or less, relative to the total amount of polyurethane polyol.

[0115] That is, from the viewpoint of water resistance and stain resistance, the content of structural units derived from hydrophobic polyol is, for example, 25% by mass or more and 93% by mass or less, preferably 28% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less, even more preferably 33% by mass or more and 75% by mass or less, and particularly preferably 35% by mass or more and 70% by mass or less, relative to the total amount of polyurethane polyol.

[0116] Furthermore, the polyurethane polyol may contain structural units derived from the above-mentioned other polyols (i.e., polyols other than hydrophobic polyols (the same applies hereinafter)), if necessary. Preferably, the polyurethane polyol contains structural units derived from the other polyols.

[0117] The content of structural units derived from other polyols is, for example, 0 mass% or more, preferably 1 mass% or more, more preferably 10 mass% or more, even more preferably 20 mass% or more, and particularly preferably 25 mass% or more, relative to the total amount of polyurethane polyol.

[0118] Furthermore, the content of structural units derived from other polyols is, for example, 74% by mass or less, preferably 70% by mass or less, more preferably 68% by mass or less, even more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less, relative to the total amount of polyurethane polyol.

[0119] That is, the content of structural units derived from other polyols relative to the total amount of polyurethane polyol is, for example, 0% by mass or more and 74% by mass or less, preferably 1% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 68% by mass or less, even more preferably 20% by mass or more and 65% by mass or less, and particularly preferably 25% by mass or more and 60% by mass or less.

[0120] The polyurethane polyol also contains structural units derived from the raw material polyol.

[0121] The content of structural units derived from the raw material polyol relative to the total amount of polyurethane polyol is, for example, 80 mass % or more, preferably 85 mass % or more, or more preferably 90 mass % or more.

[0122] The content of structural units derived from the raw material polyol relative to the total amount of polyurethane polyol is, for example, 99 mass % or less, preferably 97 mass % or less, and more preferably 95 mass % or less.

[0123] That is, the content of structural units derived from the raw material polyol is, for example, 80% by mass or more and 99% by mass or less, preferably 85% by mass or more and 97% by mass or less, and more preferably 90% by mass or more and 95% by mass or less, relative to the total amount of polyurethane polyol.

[0124] The polyurethane polyol also contains structural units derived from the raw material polyisocyanate.

[0125] The content of structural units derived from the raw material polyisocyanate relative to the total amount of polyurethane polyol is, for example, 1 mass % or more, preferably 3 mass % or more, and more preferably 5 mass % or more.

[0126] The content of structural units derived from the raw material polyisocyanate relative to the total amount of polyurethane polyol is, for example, 20 mass % or less, preferably 15 mass % or less, and more preferably 10 mass % or less.

[0127] That is, the content of the structural unit derived from the content of the raw material polyisocyanate is, for example, 1 mass % or more and 20 mass % or less, preferably 3 mass % or more and 15 mass % or less, and more preferably 5 mass % or more and 10 mass % or less, relative to the total amount of polyurethane polyol.

[0128] When the base agent (A) contains the above polyurethane polyol, excellent water resistance and excellent stain resistance are obtained.

[0129] The number average molecular weight of the polyurethane polyol (molecular weight calculated as standard polystyrene by gel permeation chromatography) is, for example, 3,000 or more and 50,000 or less, preferably 5,000 or more and 30,000 or less.

[0130] The hydroxyl value of the polyurethane polyol is, for example, 7.0 mgKOH / g or more and 56 mgKOH / g or less, preferably 11 mgKOH / g or more and 28 mgKOH / g or less. The hydroxyl value is measured by the acetylation method or the phthalation method in accordance with Method A or Method B of JIS K-1557-1 (2007).

[0131] The average number of hydroxyl groups in the polyurethane polyol is, for example, 2 or more and 6 or less, preferably 2.5 or more and 4 or less, and more preferably 3 or more and 4 or less.

[0132] [1-2] Polyols other than polyurethane polyols The main component (A) can contain polyols other than polyurethane polyols as optional components. Examples of polyols other than polyurethane polyols include known high molecular weight polyols, more specifically known polyether polyols, known polyester polyols, and known polycarbonate polyols. These can be used alone or in combination of two or more types.

[0133] In the main component (A), the content of the polyol other than the polyurethane polyol is appropriately set within a range that does not impair the excellent effects of the present invention.

[0134] From the viewpoint of water resistance and stain resistance, the main component (A) preferably does not contain any polyol other than the polyurethane polyol, i.e., the main component (A) preferably contains only the polyurethane polyol as the polyol.

[0135] [1-3] Additives The main component (A) can contain known additives as needed. Examples of additives include urethane catalysts, antioxidants, ultraviolet absorbers, crosslinking agents, antistatic agents, silane coupling agents, coating property improvers, leveling agents, antifoaming agents, curing accelerators, curing retarders, plasticizers, surfactants, pigments, fillers, organic particles, inorganic particles, metal particles, antifungal agents, processing aids, and antioxidants. These can be used alone or in combination of two or more. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0136] [1-4] Solvent The main component (A) may contain the above-mentioned organic solvent as needed. The amount and timing of addition of the organic solvent are appropriately determined depending on the purpose and application.

[0137] [1-5] Production of Main Component (A) The method for obtaining the main component (A) is not particularly limited. For example, the above-mentioned polyurethane polyol or a solution thereof can be used as the main component (A) as is. Furthermore, the above-mentioned polyols other than the polyurethane polyol can be added to the above-mentioned polyurethane polyol or a solution thereof. Furthermore, the above-mentioned additives can be added to the above-mentioned polyurethane polyol or a solution thereof. Furthermore, the solids concentration can be adjusted by adding an organic solvent to the above-mentioned polyurethane polyol or a solution thereof and / or removing part or all of the organic solvent.

[0138] When the main component (A) contains an organic solvent, the solids concentration of the main component (A) is, for example, 10% by mass or more and 95% by mass or less, preferably 30% by mass or more and 70% by mass or less. The main component (A) does not necessarily need to contain an organic solvent. That is, the solids concentration of the main component (A) may be 100% by mass.

[0139] [2] Curing agent (B) [2-1] Polyisocyanate compound The curing agent (B) is a curing agent for a two-component curing polyurethane pressure-sensitive adhesive composition. The curing agent (B) contains, for example, the polyisocyanate compound.

[0140] More specifically, examples of the polyisocyanate compound include the above-mentioned chain aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and araliphatic polyisocyanates. These can be used alone or in combination of two or more.

[0141] From the viewpoint of water resistance and stain resistance, preferably, a chain aliphatic polyisocyanate is used. That is, from the viewpoint of water resistance and stain resistance, the curing agent (B) preferably contains a chain aliphatic polyisocyanate, and more preferably consists of a chain aliphatic polyisocyanate.

[0142] Examples of the chain aliphatic polyisocyanate include the chain aliphatic polyisocyanate monomer and the chain aliphatic polyisocyanate derivative. These can be used alone or in combination of two or more. From the viewpoint of water resistance and stain resistance, a chain aliphatic polyisocyanate derivative is preferably used. That is, from the viewpoint of water resistance and stain resistance, the curing agent (B) preferably contains a chain aliphatic polyisocyanate derivative, and more preferably consists of a chain aliphatic polyisocyanate derivative.

[0143] Examples of the chain aliphatic polyisocyanate derivative include modified products of the above-mentioned chain aliphatic polyisocyanate monomers. From the viewpoint of water resistance and contamination resistance, preferred examples of the chain aliphatic polyisocyanate monomer include pentamethylene diisocyanate (PDI) and hexamethylene diisocyanate (HDI), and more preferred examples include pentamethylene diisocyanate (PDI). That is, from the viewpoint of water resistance and contamination resistance, the curing agent (B) preferably contains a modified product (i.e., a derivative) of a pentamethylene diisocyanate (PDI) monomer and / or a modified product (i.e., a derivative) of a hexamethylene diisocyanate (HDI) monomer, more preferably contains a derivative of pentamethylene diisocyanate (PDI), and even more preferably consists of a derivative of pentamethylene diisocyanate (PDI).

[0144] Examples of the modified products include uretdione-modified products, isocyanurate-modified products, allophanate-modified products, polyol-modified products, biuret-modified products, urea-modified products, oxadiazinetrione-modified products, and carbodiimide-modified products, and preferably, polyol-modified products (adducts) are used.

[0145] Examples of the polyol modified product (adduct) include an adduct obtained by adding the above-mentioned low-molecular-weight polyol to a polyisocyanate monomer. Examples of the low-molecular-weight polyol include the above-mentioned polyhydric alcohols, preferably the above-mentioned dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols, more preferably the above-mentioned trihydric alcohols, and even more preferably trimethylolpropane. That is, examples of the polyol modified product (adduct) include preferably trihydric alcohol adducts, more preferably trimethylolpropane adducts.

[0146] Preferably, the curing agent (B) is also an alicyclic polyisocyanate. More specifically, from the viewpoint of compatibility between the base agent (A) and the curing agent (B), the curing agent (B) preferably contains an alicyclic polyisocyanate, and more preferably consists of an alicyclic polyisocyanate.

[0147] Examples of alicyclic polyisocyanates include the above-mentioned alicyclic polyisocyanate monomers and the above-mentioned alicyclic polyisocyanate derivatives. These can be used alone or in combination of two or more. From the viewpoint of compatibility, alicyclic polyisocyanate derivatives are preferred. That is, from the viewpoint of compatibility between the base component (A) and the curing agent (B), the curing agent (B) preferably contains an alicyclic polyisocyanate derivative, and more preferably consists of an alicyclic polyisocyanate derivative.

[0148] Examples of the alicyclic polyisocyanate derivative include modified products of the above-mentioned alicyclic polyisocyanate monomers. From the viewpoint of compatibility, preferred alicyclic polyisocyanate monomers are isophorone diisocyanate (IPDI) and bis(isocyanatomethyl)cyclohexane (H ６XDI), and more preferably bis(isocyanatomethyl)cyclohexane (H ６ That is, from the viewpoint of compatibility, the curing agent (B) is preferably a modified product (i.e., a derivative) of a monomer of isophorone diisocyanate (IPDI) and / or bis(isocyanatomethyl)cyclohexane (H ６ XDI), and more preferably bis(isocyanatomethyl)cyclohexane (H ６ XDI), and more preferably bis(isocyanatomethyl)cyclohexane (H ６ XDI). Examples of the modified product include the above-mentioned modified products, preferably the above-mentioned isocyanurate modified product and the above-mentioned polyol modified product (preferably a trimethylolpropane adduct), and more preferably the isocyanurate modified product.

[0149] In the curing agent (B), the average number of isocyanate groups in the polyisocyanate compound is, for example, 2 or more and 6 or less, preferably 2.5 or more and 4 or less, more preferably 3 or more and 4 or less, and particularly preferably 3.

[0150] [2-2] Additives The curing agent (B) can contain known additives as needed. Examples of additives include urethane catalysts, antioxidants, ultraviolet absorbers, crosslinking agents, antistatic agents, silane coupling agents, coating property improvers, leveling agents, antifoaming agents, curing accelerators, curing retarders, plasticizers, surfactants, pigments, fillers, organic particles, inorganic particles, metal particles, antifungal agents, processing aids, and antioxidants. These can be used alone or in combination of two or more. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0151] [2-3] Solvent The curing agent (B) may contain the above-mentioned organic solvent, if necessary. The amount and timing of addition of the organic solvent are appropriately determined depending on the purpose and application.

[0152] [2-4] Production of Curing Agent (B) The method for obtaining the curing agent (B) is not particularly limited. For example, the polyisocyanate compound described above can be used as the curing agent (B) as is. The additives described above can also be added to the polyisocyanate compound. The solids concentration can also be adjusted by adding an organic solvent to the polyisocyanate compound and / or removing part or all of the organic solvent.

[0153] When the curing agent (B) contains an organic solvent, the solid content concentration of the curing agent (B) is, for example, 10% by mass or more and 95% by mass or less, preferably 40% by mass or more and 80% by mass or less. Note that the curing agent (B) does not necessarily contain an organic solvent. That is, the solid content concentration of the curing agent (B) may be 100% by mass.

[0154] [3] Effects The two-component curing polyurethane pressure-sensitive adhesive composition contains a base agent (A) and a curing agent (B). The base agent (A) contains a polyurethane polyol. The polyurethane polyol contains a reaction product of a raw material polyisocyanate and a raw material polyol. The raw material polyol also contains a hydrophobic polyol, and the hydrophobic polyol contains castor oil and / or a dimer acid polyol. The hydrophobic polyol also contains a hydrocarbon moiety having 12 to 80 carbon atoms in its molecule in a proportion of 30 to 95% by mass. The content of the hydrophobic polyol is within a predetermined range.

[0155] Therefore, the two-component curing polyurethane pressure-sensitive adhesive composition can provide a polyurethane pressure-sensitive adhesive that can relatively reduce adhesive residue upon peeling and has relatively excellent water resistance.

[0156] The main component (A) is a main component for a two-component curing polyurethane pressure-sensitive adhesive composition. This main component for a two-component curing polyurethane pressure-sensitive adhesive composition can relatively reduce adhesive residue upon peeling and can provide a polyurethane pressure-sensitive adhesive having relatively excellent water resistance.

[0157] 2. Polyurethane Pressure-Sensitive Adhesive [1] Overall Structure of Polyurethane Pressure-Sensitive Adhesive The polyurethane pressure-sensitive adhesive is formed from the above-mentioned two-component curing polyurethane pressure-sensitive adhesive composition. More specifically, the polyurethane pressure-sensitive adhesive is obtained by curing (crosslinking) the above-mentioned two-component curing polyurethane pressure-sensitive adhesive composition.

[0158] That is, the polyurethane pressure-sensitive adhesive contains a reaction product (cured reaction product) obtained by the reaction (curing reaction) between the main component (A) and the curing agent (B), and is preferably a cured reaction product.

[0159] In other words, polyurethane pressure-sensitive adhesives are not compositions (adhesives) that adhere to adherends through a reaction between a main component (A) and a curing agent (B). Polyurethane pressure-sensitive adhesives are reaction products that have adhesive properties (pressure-sensitive adhesiveness, tackiness), and are cured products that adhere to adherends.

[0160] [2] Method for Producing Polyurethane Pressure-Sensitive Adhesive The method for producing a polyurethane pressure-sensitive adhesive from the two-component curing polyurethane pressure-sensitive adhesive composition is not particularly limited, and known molding methods can be used.

[0161] More specifically, in this method, for example, the main component (A) and the curing agent (B) of the two-component curing polyurethane pressure-sensitive adhesive composition are first mixed to obtain a mixture. The mixing conditions are not particularly limited and may be appropriately set depending on the purpose and application.

[0162] The mixing ratio of the base component (A) and the curing agent (B) is adjusted based on, for example, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the curing agent (B) to the hydroxyl group in the base component (A).

[0163] More specifically, the equivalent ratio of the isocyanate groups in the curing agent (B) to the hydroxyl groups in the main agent (A) (isocyanate groups / hydroxyl groups) is, for example, 0.1 or more and less than 3.0, preferably 0.2 or more and 2.8 or less, more preferably 0.6 or more and 2.5 or less, and even more preferably 0.8 or more and 2.0 or less.

[0164] The blending ratio of the main agent (A) and the curing agent (B) can also be adjusted based on, for example, the solid content mass ratio.

[0165] More specifically, the total amount (solid content basis) of the curing agent (B) relative to 1 part by mass of the total amount (solid content basis) of the main agent (A) is, for example, 0.001 parts by mass or more and 0.300 parts by mass or less, preferably 0.010 parts by mass or more and 0.200 parts by mass or less, and more preferably 0.050 parts by mass or more and 0.150 parts by mass or less.

[0166] Next, in this method, a mixture of the base material (A) and the curing agent (B) is applied to the surface of the substrate to obtain a coating film.

[0167] The substrate is not particularly limited, and examples thereof include paper, wood, cloth, leather, resin, metal (e.g., stainless steel), glass, foam, and ceramic. These may be used alone or in combination of two or more. 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 may be appropriately set depending on the purpose and application.

[0168] The coating method is not particularly limited, and examples thereof include dip coating, spray coating, roll coating, doctor blade coating, screen printing, bar coating, and casting. These methods can be used alone or in combination of two or more.

[0169] The amount of coating is not particularly limited. For example, the coating thickness (dry thickness) is, for example, from 5 μm to 100 μm, preferably from 10 μm to 50 μm.

[0170] In this method, the coating film is then heated to cure the mixture of the base agent (A) and the curing agent (B).

[0171] The heating temperature is, for example, 30° C. or more and 200° C. or less, preferably 50° C. or more and 150° C. or less, and more preferably 80° C. or more and 130° C. The heating time is, for example, 0.5 minutes or more and 120 minutes or less, preferably 1 minute or more and 60 minutes or less, and more preferably 3 minutes or more and 10 minutes or less.

[0172] By the above heating, the mixture of the base component (A) and the curing agent (B) is cured (crosslinked) to obtain a polyurethane adhesive.

[0173] If necessary, the polyurethane adhesive can be cured. The curing temperature is, for example, 20°C to 100°C, preferably 30°C to 80°C. The curing humidity (relative humidity) is, for example, 10% RH to 80% RH, preferably 20% RH to 60% RH. The curing time is, for example, 1 day to 14 days, preferably 3 days to 7 days.

[0174] [3] Physical Properties of Polyurethane Pressure-Sensitive Adhesive The glass transition temperature of the polyurethane pressure-sensitive adhesive is, for example, from −100° C. to 20° C., preferably from −50° C. to 0° C. The glass transition temperature of the polyurethane pressure-sensitive adhesive is calculated as the temperature at which the loss tangent (tan δ) peaks, for example, by dynamic viscoelasticity measurement (heating rate 5° C. / min, frequency 10 Hz, amplitude ±0.01 mm, temperature dispersion mode).

[0175] [4] Effects The polyurethane pressure-sensitive adhesive is obtained from the two-component curing polyurethane pressure-sensitive adhesive composition, and therefore the polyurethane pressure-sensitive adhesive can relatively reduce adhesive residue upon peeling and has relatively excellent water resistance.

[0176] For this reason, polyurethane pressure-sensitive adhesives are suitable for use in a variety of industrial fields, including, for example, information equipment components, housing, building materials, automobiles, railways, daily necessities, and healthcare.

[0177] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0178] [1] Main component (A) [1-1] Polyurethane polyol Preparation Example 1 (Raw polyisocyanate) The polyisocyanate compounds shown below were prepared as raw polyisocyanates.

[0179] HDI: Hexamethylene diisocyanate PDI: Pentamethylene diisocyanate

[0180] Preparation Example 2 (Hydrophobic Polyol) As hydrophobic polyols, castor oil, dimer acid polyol, and butadiene polyol shown below were prepared.

[0181] Castor oil: Product name "Deodorized refined castor oil", number average molecular weight 933, average number of hydroxyl groups 2.7, manufactured by Toyokuni Oil Mills

[0182] Dimer acid polyol: trade name "PRIPLAST3238-LQ-(GD)", number average molecular weight 2000, average number of hydroxyl groups 2, manufactured by CRODA

[0183] Butadiene polyol: trade name "Poly bd R-45HT", number average molecular weight 2800, hydroxyl value 46.6 mg KOH / g, manufactured by Idemitsu Kosan

[0184] The castor oil and dimer acid polyol both contained hydrocarbon moieties having 12 to 80 carbon atoms in the molecule in a proportion of 30 to 95% by mass.

[0185] Preparation Example 3 (Other Polyols) The following high molecular weight polyols were prepared as other polyols (polyols other than hydrophobic polyols).

[0186] Polyester polyol: Trade name "Takelac LNB800", adipate-based condensation polyester polyol, number average molecular weight 800, average number of hydroxyl groups 2, manufactured by Mitsui Chemicals. PPG (T-5000): Trade name "Actocol T-5000", polyoxypropylene polyol, number average molecular weight 5000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals. PPG (T-3000): Trade name "Actocol T-3000", polyoxypropylene polyol, number average molecular weight 3000, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals. PPG (T-1500): Trade name "Actocol T-1500", polyoxypropylene polyol, number average molecular weight 1500, average number of hydroxyl groups 3, manufactured by Mitsui Chemicals.

[0187] Examples A1 to A23 and Comparative Examples A1 to A9: Raw material polyisocyanate and raw material polyol were placed in a predetermined reaction vessel and mixed according to the formulations shown in Tables 1 to 5. Ethyl acetate was then added to the reaction vessel to adjust the solids concentration. A urethane catalyst (dibutyltin dilaurate) was then added to the reaction vessel.

[0188] In each Example and Comparative Example (except Comparative Example A8), the equivalent ratio of isocyanate groups in the raw polyisocyanate to hydroxyl groups in the raw polyol (isocyanate groups / hydroxyl groups) was 0.5 to 0.85. In Comparative Example A8, the amount of hydroxyl groups was relatively large, and the equivalent ratio of isocyanate groups in the raw polyisocyanate to hydroxyl groups in the raw polyol (isocyanate groups / hydroxyl groups) was 0.29. In each Example and Comparative Example, the amount of urethanization catalyst was 200 ppm relative to the total amount of the raw polyisocyanate, raw polyol, and urethanization catalyst.

[0189] Tables 1 to 5 show the mass ratios of the solid content of the raw polyol and the solid content of the raw polyisocyanate.

[0190] Next, in the reaction vessel, the raw material polyisocyanate and raw material polyol were subjected to a urethane reaction at 75° C. for 15 hours, and the disappearance of the isocyanate groups was confirmed.

[0191] As a result of the above, a polyurethane polyol and a solution thereof (solid content concentration: 50% by mass) were obtained as reaction products of the raw material polyisocyanate and raw material polyol.

[0192] The polyurethane polyol solution was used as a base component (base component (A)) for a two-component curing polyurethane pressure-sensitive adhesive composition.

[0193] [2] Curing Agent (B) Preparation Example 4 (Polyisocyanate Compound) The following polyisocyanate compounds were prepared.

[0194] HDI-TMP: Trade name "Takenate D-160N", a trimethylolpropane adduct of hexamethylene diisocyanate, ethyl acetate solution (solid content concentration 75% by mass), manufactured by Mitsui Chemicals

[0195] PDI-TMP: a trimethylolpropane adduct of pentamethylene diisocyanate (PDI) produced according to the description in Example 1 of

[0101] to

[0103] of JP-A-2010-265364.

[0196] The method for producing the above PDI-TMP is shown below.

[0197] More specifically, 500 parts by mass of pentamethylene diisocyanate (PDI) and 50.0 parts by mass of trimethylolpropane (TMP) were charged into a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, to obtain a mixture. The equivalent ratio of the isocyanate groups of PDI to the hydroxyl groups of TMP (isocyanate groups / hydroxyl groups) was 5.8. The mixture was then heated to 75°C to dissolve the trimethylolpropane. The mixture was then reacted at 83°C until the unreacted isocyanate group concentration reached 41.0% by mass.

[0198] Next, the temperature of the reaction solution was lowered to 55°C. Thereafter, 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, allowed to stand for 10 minutes, and the extraction solvent was removed. This extraction procedure was repeated four times.

[0199] The reaction mixture was then heated to 80°C under reduced pressure to remove the extraction solvent remaining in the reaction mixture. This resulted in the production of a trimethylolpropane adduct of PDI. A solvent (ethyl acetate) was added to the trimethylolpropane adduct of PDI to adjust the solids concentration to 75% by mass.

[0200] IPDI-trimer: A solution obtained by diluting an isocyanurate derivative of isophorone diisocyanate (trade name "VESTANAT T1890 / 100", manufactured by EVONIK) with ethyl acetate to adjust the solid content concentration to 75% by mass.

[0201] IPDI-TMP: Trade name "Takenate D-140N", a trimethylolpropane adduct of isophorone diisocyanate, ethyl acetate solution (solid content concentration 75% by mass), manufactured by Mitsui Chemicals

[0202] H ６ XDI-trimer: Trade name "Takenate D-127N", an isocyanurate derivative of 1,3-bis(isocyanatomethyl)cyclohexane, ethyl acetate solution (solid content concentration 75% by mass), manufactured by Mitsui Chemicals

[0203] [3] Two-component curing polyurethane adhesive compositions and polyurethane adhesives Examples B1 to B23 and Comparative Examples B1 to B9 Two-component curing polyurethane adhesive compositions and polyurethane adhesives were obtained using the main component (A) described in 1) above and the curing agent (B) described in 2) above.

[0204] More specifically, the main component (A) and the curing agent (B) were combined according to the descriptions in Tables 1 to 5 to obtain two-component curing polyurethane pressure-sensitive adhesive compositions (uncured resin compositions).

[0205] Next, the base component (A) and the curing agent (B) were mixed according to the descriptions in Tables 1 to 5. This gave a mixture of a two-component curing polyurethane pressure-sensitive adhesive composition.

[0206] In Examples B2, B5, B7 to B20, Comparative Examples B2, B5 and B7, the equivalent ratio of the isocyanate groups in the curing agent (B) to the hydroxyl groups in the main component (A) (isocyanate groups / hydroxyl groups) was approximately 1.0.

[0207] In addition, in Example B1, Example B4, Comparative Example B1, and Comparative Example B4, the amount of curing agent (B) was relatively small, and the equivalent ratio of the isocyanate groups in the curing agent (B) to the hydroxyl groups in the main component (A) (isocyanate groups / hydroxyl groups) was approximately 0.2.

[0208] In addition, in Examples B3, B6, Comparative Examples B3, and B6, the amount of curing agent (B) was relatively large, and the equivalent ratio of the isocyanate groups in the curing agent (B) to the hydroxyl groups in the main component (A) (isocyanate groups / hydroxyl groups) was approximately 1.9.

[0209] In Comparative Example B8, the amount of hydroxyl groups contained in the main component (B) was relatively large, and the equivalent ratio of the isocyanate groups in the curing agent (B) to the hydroxyl groups in the main component (A) (isocyanate groups / hydroxyl groups) was approximately 0.2.

[0210] Tables 1 to 5 show the blending ratio of the curing agent (B) having a solid content concentration of 75% by mass to the base agent (A) having a solid content concentration of 50% by mass.

[0211] The mixture of the two-component curing polyurethane pressure-sensitive adhesive composition was then applied to a polyethylene terephthalate (PET) film to obtain a coating film. The amount of coating was adjusted so that the dry thickness of the coating film was 50 μm.

[0212] The coating film was then heated at 110°C for 3 minutes to react and cure the main component (A) and the curing agent (B). This cured the two-component curing polyurethane adhesive composition, yielding a polyurethane adhesive. The polyurethane adhesive was then covered with a release film and aged in a dryer at 60°C for 3 days.

[0213] [4] Evaluation (1) Water Resistance A polyurethane adhesive was cut into a width of 25 mm. The release film was peeled off from the polyurethane adhesive. The polyurethane adhesive was pressed onto a stainless steel plate (hereinafter referred to as SUS plate), and a 2 kg roller was rolled back and forth twice on the polyurethane adhesive. This resulted in a pressure-bonding of the polyurethane adhesive to the SUS plate.

[0214] Then, immediately after pressure bonding, the polyurethane pressure-sensitive adhesive and the SUS plate were peeled off using a tensile tester (pulling speed: 300 mm / min, peel angle: 180°C), thereby measuring the adhesive strength of the polyurethane pressure-sensitive adhesive before the water resistance test.

[0215] The polyurethane adhesive was also subjected to a water resistance test, namely, the polyurethane adhesive and a stainless steel plate were pressure-bonded together, and then the two were left to stand in a thermo-hygrostat at 25°C and a relative humidity of 100% for 72 hours.

[0216] Then, the polyurethane pressure-sensitive adhesive and the SUS plate after the water resistance test were peeled off using a tensile tester (pulling speed: 300 mm / min, peel angle: 180°C), thereby measuring the adhesive strength of the polyurethane pressure-sensitive adhesive after the water resistance test.

[0217] Thereafter, the adhesive strength retention rate after the water resistance test was calculated using the following formula: Adhesive strength retention rate (%) = [adhesive strength after water resistance test (N / 25 mm) / adhesive strength before water resistance test (N / 25 mm)] x 100

[0218] The water resistance was evaluated according to the following criteria, and the results are shown in Tables 1 to 5.

[0219] A: The adhesive strength maintenance rate was more than 30%. B: The adhesive strength maintenance rate was more than 10% and 30% or less. C: The adhesive strength maintenance rate was 10% or less.

[0220] (2) Stain Resistance (Adhesive Residue) A polyurethane adhesive was cut into a width of 25 mm. The release film was peeled off from the polyurethane adhesive. The polyurethane adhesive was pressed onto a SUS plate, and a 2 kg roller was rolled back and forth twice on the polyurethane adhesive. This resulted in the polyurethane adhesive and the SUS plate being pressed together.

[0221] In addition, the area of ​​the portion where the SUS plate and the polyurethane adhesive were pressure-bonded (hereinafter referred to as the bonded area) was determined.

[0222] The polyurethane adhesive was then subjected to a stain resistance test. That is, the polyurethane adhesive and a SUS plate were pressure-bonded together, and then the two were left to stand in a thermo-hygrostat at 60°C and a relative humidity of 90% for 72 hours.

[0223] After the contamination resistance test, the polyurethane adhesive and the SUS plate were peeled off using a tensile tester (pulling speed: 300 mm / min, peel angle: 180°C), and the presence or absence of polyurethane adhesive remaining (adhering) to the SUS plate was confirmed visually.

[0224] In addition, the area of ​​the portion where the polyurethane adhesive remained on the SUS plate (hereinafter referred to as the remaining area) was determined.

[0225] Then, the ratio of the remaining area to the applied area was calculated.

[0226] The stain resistance was evaluated according to the following criteria, and the results are shown in Tables 1 to 5.

[0227] A: No polyurethane adhesive was found remaining (adhering) on ​​the SUS plate. B: Polyurethane adhesive was found remaining (adhering) on ​​the SUS plate. The ratio of the remaining area to the applied area was 30% or less. C: Polyurethane adhesive was found remaining (adhering) on ​​the SUS plate. The ratio of the remaining area to the applied area exceeded 30%.

[0228] (3) Compatibility In Examples B1 to B6 and B19 to B21, the degree of turbidity of the mixture of the main agent (A) and the curing agent (B) was visually confirmed. The increase in turbidity of the mixture relative to the turbidity of the main agent (A) before mixing with the curing agent (B) was confirmed according to the following criteria to evaluate compatibility. The results are shown in Tables 1 to 5.

[0229] A: The base component (A) and the curing agent (B) were blended, and no increase in turbidity was observed in the mixture even after 1 hour or more had passed. B: The base component (A) and the curing agent (B) were blended, and an increase in turbidity was observed in the mixture within 1 hour.

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[0234]

Claims

1. A two-component curing polyurethane adhesive composition comprising a main component (A) and a curing agent (B), wherein the main component (A) contains a polyurethane polyol, the polyurethane polyol containing a reaction product of a raw polyisocyanate and a raw polyol, the raw polyol containing a hydrophobic polyol having a hydrocarbon moiety having 12 to 80 carbon atoms in the molecule in a proportion of 30 to 95 mass%, the hydrophobic polyol containing castor oil and / or dimer acid polyol, and the proportion of the hydrophobic polyol is 25 to 93 mass%, based on the total amount of the raw polyisocyanate and the raw polyol.

2. The two-component curing polyurethane pressure-sensitive adhesive composition according to claim 1, wherein the hydrophobic polyol contains a castor oil and a dimer acid polyol, and the castor oil content is 0.5 parts by mass or more per 1 part by mass of the dimer acid polyol.

3. The two-component curing polyurethane pressure-sensitive adhesive composition according to claim 1, wherein the raw material polyol further contains a polyether polyol.

4. The two-component curing polyurethane adhesive composition according to claim 1, wherein the raw material polyisocyanate contains a chain aliphatic polyisocyanate monomer.

5. The two-component curing polyurethane pressure-sensitive adhesive composition according to claim 1, wherein the curing agent (B) contains an alicyclic polyisocyanate derivative.

6. The two-component curing polyurethane pressure-sensitive adhesive composition according to claim 1, wherein the curing agent (B) contains a chain aliphatic polyisocyanate derivative.

7. The two-component curing polyurethane adhesive composition according to claim 1, wherein the curing agent (B) contains a derivative of pentamethylene diisocyanate.

8. A polyurethane adhesive formed from the two-component curing polyurethane adhesive composition according to any one of claims 1 to 7, comprising a cured product of the main component (A) and the main component (B) reacted with each other.

9. A base for a two-component curing polyurethane adhesive composition, comprising a polyurethane polyol, the polyurethane polyol comprising a reaction product of a raw material polyisocyanate and a raw material polyol, the raw material polyol comprising a hydrophobic polyol containing hydrocarbon moieties having 12 to 80 carbon atoms in the molecule in a proportion of 30 to 95 mass%, the hydrophobic polyol comprising castor oil and / or dimer acid polyol, the proportion of the hydrophobic polyol being 25 to 93 mass%, based on the total amount of the raw material polyisocyanate and the raw material polyol.

10. The base agent for a two-component curing polyurethane adhesive composition according to claim 9, wherein the content of the castor oil is 0.5 parts by mass or more per 1 part by mass of the dimer acid polyol.

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