Patent Description:
Flexible packaging materials for packaging contents such as food, medical products, cosmetics, and the like utilize a laminate in which various plastic films are bonded together, or a plastic film and a metal-deposited film or a metal foil are bonded together with an adhesive layer interposed therebetween. Hydroxyl/isocyanate-based two-component curable urethane adhesives are widely used as adhesives for forming the adhesive layer. However, in recent years, from the viewpoint of cost reduction, films with a low degree of surface treatment are increasingly used, and the adhesive is required to further improve its adhesion force to plastic films, metal-deposited films, or metal foils.

Patent Literature <NUM> describes that the adhesive with two types of specific polyester polyols including <NUM> to <NUM>% by mass of polyester polyols having a number average molecular weight of <NUM> to as polyol components is excellent in adhesion force and tearability. <CIT> discloses <NUM> polyurethane adhesive compositions for making food packaging materials , wherein the adhesives are characterised by a high laminating strength, good coatability and beneficial oxygen barrier properties.

<CIT> and <CIT> disclose also <NUM> polyurethane laminating adhesive compositions.

The adhesive described in Patent Literature <NUM> includes, as a main resin, a polyester polyol having a high affinity with a diluent solvent and a low solvent removability, and problems such as poor appearance and a residual solvent may thus occur at high speed coating such as <NUM>/min.

Meanwhile, an adhesive obtained by combining <NUM> to <NUM>% by mass of a polyester polyol having a number average molecular weight of <NUM> to <NUM>,<NUM>, and a polyether urethane polyol is, despite the excellent coating properties of the polyether urethane polyol itself, problematic in that coating unevenness in high speed coating occurs due to reduced compatibility caused by the combination of resins with different skeletons.

Thus, there has been a demand for the development of an adhesive capable of achieving both excellent adhesion force and suppression of coating unevenness and a residual solvent during high speed coating.

Therefore, an object of the present invention is to provide a two-component curable adhesive that has excellent adhesion force, does not cause coating unevenness in high speed coating, and has a little residual solvent, and a laminate and a package that use the adhesive and have excellent adhesion force and a good appearance.

As a result of extensive study, the present inventors have found that the above problem can be solved by combining a specific polyester polyol in a predetermined amount with a polyether urethane polyol, and have completed the present invention.

One embodiment of the present invention is a two-component curable adhesive including a polyol component and a polyisocyanate component, in which the polyol component includes a polyether urethane polyol (A) and a polyester polyol (B) having a number average molecular weight of <NUM> to <NUM>,<NUM>, and the content of the polyester polyol (B) is <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the polyether urethane polyol (A).

One embodiment of the present invention relates to the two-component curable adhesive, in which the polyester polyol (B) has an acid value of <NUM> to <NUM> mgKOH/g.

One embodiment of the present invention relates to the two-component curable adhesive, in which the polyether urethane polyol (A) has a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM>.

One embodiment of the present invention relates to the two-component curable adhesive, in which the polyisocyanate component includes a polyether urethane polyisocyanate that is a reaction product of an aromatic diisocyanate and a polyether polyol.

One embodiment of the present invention relates to the two-component curable adhesive, further including a hydroxy acid having two carboxy groups.

One embodiment of the present invention relates to the two-component curable adhesive in which the content of the hydroxy acid having two carboxy groups is <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the polyether urethane polyol (A).

One embodiment of the present invention relates to the two-component curable adhesive, in which the hydroxy acid having two carboxy groups includes an aliphatic hydroxy acid having <NUM> to <NUM> carbon atoms.

One embodiment of the present invention relates to a laminate including a layer comprising the two-component curable adhesive between a first base material and a second base material.

One embodiment of the present invention relates to a package including the laminate.

The present invention can provide a two-component curable adhesive that has excellent adhesion force, does not cause coating unevenness in high speed coating, and has a little residual solvent, and a laminate and a package that use the adhesive and have excellent adhesion force and a good appearance.

The two-component curable adhesive according to the present invention is an adhesive that cures through a chemical reaction between an isocyanate group and a hydroxyl group, and includes a polyol component having a polyether urethane polyol (A) and a polyester polyol (B) having a number average molecular weight of <NUM> to <NUM>,<NUM>, and a polyisocyanate component, in which the content of the polyester polyol (B) is <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the polyether urethane polyol (A).

Including a predetermined range of the polyester polyol (B) having a number average molecular weight of <NUM> to <NUM>,<NUM> does not reduce compatibility with the polyether urethane polyol (A), thus, when high speed coating is performed, it can provide an adhesive that suppresses coating unevenness, has a little residual solvent, and has excellent adhesion force.

The polyol component in the present invention includes the polyether urethane polyol (A) and <NUM> to <NUM> parts by mass of the polyester polyol (B) having a number average molecular weight of <NUM> to <NUM>,<NUM> based on <NUM> parts by mass of the polyether urethane polyol (A). The content of the polyester polyol (B) is preferably <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the polyether urethane polyol (A). It is preferable that the content of the polyester polyol (B) is in the range of <NUM> to <NUM> parts by mass because the adhesive strength is more excellent.

The polyether urethane polyol is not particularly limited, and is preferably a compound having a hydroxyl group and a urethane bond, the compound being a reaction product obtained by reacting a polyether polyol and a polyisocyanate under the condition of excessive hydroxyl groups. These polyether urethane polyols may be used singly or in combination of two or more thereof.

The polyether polyol may be a compound having two or more hydroxyl groups and two or more ether bonds in the molecule.

Examples of the polyether polyol include: polyalkylene glycols such as polyethylene glycol, polytrimethylene glycol, polypropylene glycol, polytetramethylene glycol, and polybutylene glycol; polyethylene glycol/polypropylene glycol block copolymers; and propylene oxide/ethylene oxide random polyethers.

In addition, oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran are addition polymerized to low molecular weight polyol initiators such as water, ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, and sucrose to provide an addition polymer, and this addition polymer may be used as the polyether polyol.

Examples of the addition polymer include propylene glycol propylene oxide adducts, glycerin propylene oxide adducts, sorbitol-based propylene oxide adducts, and sucrose-based propylene oxide adducts.

The number average molecular weight of the polyether polyol is preferably <NUM> or more and <NUM>,<NUM> or less, more preferably <NUM> or more and <NUM>,<NUM> or less. These polyether polyols may be used singly or in combination of two or more thereof.

The polyisocyanate may be a compound having two or more isocyanate groups.

Examples of the polyisocyanate include an aromatic polyisocyanate, an araliphatic polyisocyanate, an aliphatic polyisocyanate, or an alicyclic polyisocyanate, and the polyisocyanate may be one obtained by modifying these polyisocyanates.

These polyisocyanates may be used singly or in combination of two or more thereof.

Examples of the aromatic polyisocyanate include: aromatic diisocyanates such as diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, phenylene diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate; and aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate.

Examples of the araliphatic polyisocyanate include: araliphatic diisocyanates such as <NUM>,<NUM>- or <NUM>,<NUM>-xylylene diisocyanate or a mixture thereof, and ω,ω'-diisocyanato-<NUM>,<NUM>-diethylbenzene, <NUM>,<NUM>- or <NUM>,<NUM>-bis(<NUM>-isocyanato-<NUM>-methylethyl)benzene or a mixture thereof.

Examples of the aliphatic polyisocyanate include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, <NUM>,<NUM>-propylene diisocyanate, <NUM>,<NUM>-butylene diisocyanate, <NUM>,<NUM>-butylene diisocyanate, <NUM>,<NUM>-butylene diisocyanate, <NUM>,<NUM>,<NUM>- or <NUM>,<NUM>,<NUM>-trimethylhexamethylene diisocyanate, <NUM>,<NUM>-diisocyanate methyl caproate, lysine diisocyanate, and a dimer acid diisocyanate.

Examples of the alicyclic polyisocyanate include alicyclic diisocyanates such as <NUM>,<NUM>-cyclohexane diisocyanate, <NUM>,<NUM>-cyclohexane diisocyanate, isophorone diisocyanate, <NUM>,<NUM>'-methylenebis(cyclohexyl isocyanate), methyl <NUM>,<NUM>-cyclohexane diisocyanate, methyl <NUM>,<NUM>-cyclohexane diisocyanate, <NUM>,<NUM>-bis(isocyanatomethyl)cyclohexane, <NUM>,<NUM>-bis(isocyanatomethyl)cyclohexane, and norbornene diisocyanate.

Examples of the modified polyisocyanate include an allophanate-type modified product, an isocyanurate-type modified product, a biuret-type modified product, and an adduct-type modified product.

The polyether urethane polyol (A) is preferably a reaction product of a bifunctional or trifunctional polyalkylene glycol having a number average molecular weight of <NUM> to <NUM>,<NUM> and an aromatic diisocyanate.

In addition, from the viewpoint of achieving both adhesive strength and coating suitability, the weight average molecular weight of the polyether urethane polyol (A) is preferably <NUM>,<NUM> or more, more preferably <NUM>,<NUM> or more, and preferably <NUM>,<NUM> or less, more preferably <NUM>,<NUM> or less.

The polyether urethane polyol (A) in the present invention may be modified, or may be a polyether urethane polyol reacted with an acid anhydride to introduce a carboxyl group.

Examples of the acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and a trimellitic acid ester anhydride. Examples of the trimellitic acid ester anhydride include ester compounds obtained by subjecting alkylene glycols or alkanetriols, having <NUM> to <NUM> carbon atoms to an esterification reaction with trimellitic anhydride. More specific examples of the trimellitic acid ester anhydride include ethylene glycol bis-anhydro trimellitate and propylene glycol bis-anhydro trimellitate.

The polyester polyol (B) can be selected from known polyester polyols having a number average molecular weight of <NUM> to <NUM>,<NUM>, and these may be used singly or in combination of two or more thereof.

Examples of the polyester polyol (B) include a polyester polyol obtained by reacting a carboxyl group component and a hydroxyl group component; and a polyester polyol obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone).

Examples of the carboxyl group component include: dibasic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, and itaconic anhydride; dialkyl esters thereof; or mixtures thereof. Examples of the hydroxyl group component include: diols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, dineopentyl glycol, trimethylolpropane, glycerin, <NUM>,<NUM>-hexanediol, <NUM>,<NUM>-butanediol, <NUM>,<NUM>-cyclohexanedimethanol, <NUM>-methyl-<NUM>,<NUM>-pentanediol, <NUM>,<NUM>'-dimethylolheptane, <NUM>,<NUM>-nonanediol, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, polyether polyol, polycarbonate polyol, polyolefin polyol, acrylic polyol, and polyurethane polyol; or mixtures thereof.

These carboxyl group components and hydroxyl group components may be used each singly, or in combination of two or more thereof.

The polyester polyol (B) may be a polyester urethane polyol reacted with a diisocyanate, or may be one reacted with an acid anhydride to introduce a carboxyl group.

Examples of the diisocyanate include <NUM>,<NUM>-tolylene diisocyanate, <NUM>,<NUM>-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, <NUM>,<NUM>-naphthalene diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate.

Examples of the acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and a trimellitic acid ester anhydride.

Examples of the trimellitic acid ester anhydride include ester compounds obtained by subjecting alkylene glycols or alkanetriols, having <NUM> to <NUM> carbon atoms to an esterification reaction with trimellitic anhydride. More specific examples of the trimellitic acid ester anhydride include ethylene glycol bis-anhydro trimellitate and propylene glycol bis-anhydro trimellitate.

It is important that the polyester polyol (B) has a number average molecular weight of <NUM> to <NUM>,<NUM>, preferably <NUM>,<NUM> to <NUM>,<NUM>. If the number average molecular weight is less than <NUM>, sufficient adhesion force cannot be obtained, and if it is more than <NUM>,<NUM>, the compatibility with polyether urethane polyol is lowered, causing coating unevenness.

The number average molecular weight and weight average molecular weight in the present description are values in terms of standard polystyrene by using GPC (gel permeation chromatography) manufactured by Showa Denko K. and using tetrahydrofuran as a solvent.

When the polyester polyol (B) includes a plurality of polyester polyols in order to satisfy various physical properties required for packaging materials, the number average molecular weight of the polyester polyol (B) can be obtained from the number average molecular weight and the mass ratio of each polyester polyol.

The acid value of the polyester polyol (B) is preferably <NUM> to <NUM> mgKOH/g, more preferably <NUM> to <NUM> mgKOH/g, still more preferably <NUM> to <NUM> mgKOH/g. The acid value is preferably <NUM> mgKOH/g or more, because the adhesion force is further improved, and it is preferably <NUM> mgKOH/g or less, because the pot life is excellent.

In addition, when the two-component curable adhesive according to the present invention includes a hydroxy acid having two carboxy groups, which will be described later, the acid value of the polyester polyol (B) is preferably <NUM> to <NUM> mgKOH/g. An acid value of <NUM> mgKOH/g or more exhibits excellent adhesion force to inks containing nitrocellulose resin as a binder component, and an acid value of <NUM> mgKOH/g or less exhibits excellent high speed coating suitability. In the above case, the acid value of the polyester polyol (B) is preferably <NUM> to <NUM> mgKOH/g, more preferably <NUM> to <NUM> mgKOH/g.

When the polyester polyol (B) includes a plurality of polyester polyols, the acid value of the polyester polyol (B) can be determined from the acid value and the mass ratio of each polyester polyol.

The polyester polyol (B) is preferably an acid anhydride modified product obtained by reacting a part of hydroxyl groups of a polyester polyol obtained by reacting a carboxyl group component and a hydroxyl group component with an acid anhydride. The hydroxyl group component preferably includes <NUM> to <NUM> % by mole of <NUM>,<NUM>-butanediol in <NUM> moles of the total hydroxyl group component. Using such a polyester polyol can provide an adhesive composition that is excellent in adhesion force, does not cause coating unevenness in high speed coating, and has a little residual solvent.

The polyol component in the present invention can contain polyols other than the polyether urethane polyol (A) and the polyester polyol (B) as long as the effect of the present invention is not impaired.

Examples of other includable polyols include a polyester polyol or polyester urethane polyol, having a number average molecular weight of less than <NUM>, a polyester polyol or polyester urethane polyol, having a number average molecular weight of more than <NUM>,<NUM>, a polycarbonate polyol, a polycaprolactone polyol, a polyether polyol, a polyolefin polyol, an acrylic polyol, a silicone polyol, a castor oil-based polyol, and a fluorine-based polyol, and the above other polyol may be an acid modified product in which a part of hydroxyl groups in the polyol are acid-modified.

These other polyols may be used singly or in combination of two or more thereof.

The polyisocyanate component in the present invention may be any compound having two or more isocyanate groups, and can be selected from known polyisocyanates. Examples of the polyisocyanate component include an aromatic polyisocyanate, an araliphatic polyisocyanate, an aliphatic polyisocyanate, an alicyclic polyisocyanate, or a modified product thereof. These polyisocyanates may be used singly or in combination of two or more thereof.

The aromatic polyisocyanate, the araliphatic polyisocyanate, the aliphatic polyisocyanate, the alicyclic polyisocyanate, and the modified product thereof can be referred to the description of the polyisocyanate in the polyether urethane polyol (A).

The polyisocyanate component in the present invention is preferably a polyisocyanate component including a reaction product having isocyanate groups and urethane bonds as a modified polyisocyanate, the polyisocyanate component being obtained by reacting the above polyisocyanate component and polyol under a condition of excessive isocyanate groups.

The polyol that forms the modified polyisocyanate is not particularly limited and can be selected from known polyols. Examples of the polyol include a polyester polyol, a polyester urethane polyol, a polycarbonate polyol, a polycaprolactone polyol, a polyether polyol, a polyether urethane polyol, a polyolefin polyol, an acrylic polyol, a silicone polyol, a castor oil-based polyol, and a fluorine-based polyol.

From the viewpoint of lamination strength, the polyisocyanate component is more preferably a reaction product of the above polyisocyanate component and polyether polyol, and more preferably a polyether urethane polyisocyanate that is a reaction product of an aromatic diisocyanate and a polyether polyol.

The above aromatic diisocyanate and polyether polyol can be referred to the description of the polyisocyanate and polyether polyol in the polyether urethane polyol (A).

The weight average molecular weight of the polyisocyanate component is preferably <NUM>,<NUM> to <NUM>,<NUM>.

The adhesive according to the present invention can be used as a solvent-type or non-solvent-type adhesive, and may contain a solvent if necessary. The term "solvent" as used in the present description refers to a highly soluble organic solvent capable of dissolving the polyol component and the polyisocyanate component.

Examples of the highly soluble organic solvent include toluene, xylene, methylene chloride, tetrahydrofuran, methanol, ethanol, isopropyl alcohol, methyl acetate, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone, cyclohexanone, toluol, xylol, n-hexane, and cyclohexane.

The organic solvent is preferably inert to the polyisocyanate component, and examples thereof include esters such as ethyl acetate; ketones such as methyl ethyl ketone; and aromatic hydrocarbons such as toluene and xylene.

The viscosity of the adhesive according to the present invention is preferably <NUM> to <NUM>,<NUM> mPa·s, more preferably <NUM> to <NUM>,<NUM> mPa·s at a room temperature (for example, <NUM>) to <NUM>. In addition, the viscosity of the adhesive according to the present invention is preferably <NUM> to <NUM>,<NUM> mPa·s, more preferably <NUM> to <NUM>,<NUM> mPa·s at a room temperature to <NUM>. When the adhesive according to the present invention has a viscosity of <NUM> to <NUM>,<NUM> mPa·s at a room temperature to <NUM>, it can be used as a non-solvent-type adhesive.

For example, when the viscosity of the adhesive is higher than the above range, it may be diluted with the above organic solvent. The content of the organic solvent depends on the required viscosity, and the organic solvent is typically desirable to be contained in the range of <NUM> to <NUM>% by mass based on the resin.

The adhesive according to the present invention is a two-component curable urethane adhesive obtained by blending a polyol component and a polyisocyanate component. The blending amount of the polyisocyanate component in the adhesive is preferably in the range of <NUM> to <NUM>% by mass, more preferably in the range of <NUM> to <NUM>% by mass, and still more preferably in the range of <NUM> to <NUM>% by mass, based on the polyol component.

In addition, regarding the blending ratio between the polyol component and the polyisocyanate component, the equivalent ratio of all isocyanate groups contained in the isocyanate component to all hydroxyl groups contained in the polyol component, i.e., [NCO/OH], is preferably in the range of <NUM> to <NUM>, more preferably in the range of <NUM> to <NUM>.

The adhesive according to the present invention preferably has an acid value of <NUM> mgKOH/g or less, more preferably <NUM> mgKOH/g or less, immediately after blending the polyol component and the polyisocyanate component.

The adhesive according to the present invention may contain components other than the polyol component and the polyisocyanate component in order to satisfy various physical properties required for adhesives or packaging materials. These other components may be blended with either the polyol component or the polyisocyanate component, or may be added when blending the polyol component and the polyisocyanate component. These other components may be used singly or in combination of two or more thereof.

The adhesive according to the present invention can further contain a hydroxy acid having two carboxyl groups in order to increase adhesion force.

By using the polyester polyol (B) in a predetermined amount and the hydroxy acid having two carboxy groups in combination with the polyether urethane polyol (A), the following effect can be obtained. That is, the length of the bond of the polyether urethane is controlled; the acid group such as the carboxy group catches an additive; and furthermore, the hydroxy acid having two carboxyl groups acts as a bridge between the adhesive layer and the base material without being affected by the ink components, thereby exhibiting excellent adhesion force. As a result, the obtained adhesive can easily suppress deterioration in adhesive strength over time. A silane coupling agent, which will be described below, may be used as the adhesive; however, such an effect can be easily obtained without using the silane coupling agent.

The above hydroxy acid may be a compound having two carboxy groups and one or more hydroxyl groups in the molecule, and can be selected from known hydroxy acids. By using such a hydroxy acid, one carboxy group binds to the surface of the base material and the other carboxy group binds to the adhesive, forming a bridge at the interface between the adhesive layer and the base material. Furthermore, the carboxyl group catches the migrating component in the ink. As a result, the adhesion force can be further improved without being affected by the components of the ink.

Examples of the hydroxy acid with two carboxy groups include an aliphatic hydroxy acid. The aliphatic hydroxy acid is not particularly limited, and examples thereof include malic acid, tartaric acid, citric acid, isocitric acid, and isomers thereof.

The hydroxy acid in the present invention is preferably an aliphatic hydroxy acid, more preferably with <NUM> to <NUM> carbon atoms, still more preferably with <NUM> to <NUM> carbon atoms.

These hydroxy acids may be used singly or in combination of two or more thereof.

The content of the hydroxy acid is preferably <NUM> to <NUM> parts by mass, more preferably <NUM> to <NUM> parts by mass, still more preferably <NUM> to <NUM> parts by mass, based on <NUM> parts by mass of the polyether urethane polyol (A). The content is preferably in the range of <NUM> to <NUM> parts by mass, because both pot life and adhesive strength can be easily achieved, and high speed coatability and adhesive strength are excellent.

The adhesive according to the present invention can further contain a silane coupling agent in order to improve hot water resistance. Examples of the silane coupling agent include: trialkoxysilanes having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane; trialkoxysilanes having an amino group such as <NUM>-aminopropyltriethoxysilane and N-(<NUM>-aminoethyl)<NUM>-aminopropyltrimethoxysilane; and trialkoxysilanes having a glycidyl group such as <NUM>-glycidoxypropyltrimethoxysilane, <NUM>-(<NUM>,<NUM>-epoxycyclohexyl)ethyltrimethoxysilane, and <NUM>-glycidoxypropyltriethoxysilane. The amount of the silane coupling agent added is preferably <NUM> to <NUM>% by mass, more preferably <NUM> to <NUM>% by mass, based on the solid content of the adhesive.

The adhesive according to the present invention can further contain an oxyacid of phosphorus or a derivative thereof in order to increase acid resistance. Among phosphorus oxyacids or derivatives thereof, the phosphorus oxyacid may be one having at least one free oxyacid. Examples of the phosphorus oxyacid include: phosphoric acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, and hypophosphoric acid; and condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid. In addition, examples of derivatives of phosphorus oxyacids include those obtained by partially esterifying the above phosphorus oxyacids leaving at least one free oxyacid with alcohols. Examples of these alcohols include: aliphatic alcohols such as methanol, ethanol, ethylene glycol, glycerin; and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol, and phloroglycinol. The amount of the phosphorus oxyacid or the derivative thereof added is preferably <NUM> to <NUM>% by mass, more preferably <NUM> to <NUM>% by mass, and still more preferably <NUM> to <NUM>% by mass, based on the solid content of the adhesive.

The adhesive according to the present invention may further contain a leveling agent or an antifoaming agent to improve the appearance of the laminate. Examples of the leveling agent include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, an acrylic-based copolymer, a methacrylic-based copolymer, polyether-modified polymethylalkylsiloxane, an acrylic acid alkyl ester copolymer, a methacrylic acid alkyl ester copolymer, and lecithin.

Examples of the antifoaming agent include: a silicone resin; a silicone solution; and a copolymer of alkyl vinyl ether, alkyl acrylate, and alkyl methacrylate.

The adhesive according to the present invention can further contain a reaction accelerator to promote the urethanization reaction. Examples of the reaction accelerator include: metal-based catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimaleate; tertiary amines such as <NUM>,<NUM>-diaza-bicyclo(<NUM>,<NUM>,<NUM>)undecene-<NUM>, <NUM>,<NUM>-diazabicyclo(<NUM>,<NUM>,<NUM>)nonene-<NUM>, and <NUM>-dibutylamino-<NUM>,<NUM>-diazabicyclo(<NUM>,<NUM>,<NUM>)undecene-<NUM>; and reactive tertiary amines such as triethanolamine.

The adhesive according to the present invention may contain various additives as long as the effect of the present invention is not impaired. Examples of the additive include inorganic fillers such as silica, alumina, mica, talc, aluminum flakes, and glass flakes, layered inorganic compounds, stabilizers (antioxidants, heat stabilizers, UV absorbers, hydrolysis inhibitors, and the like), rust inhibitors, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, coloring agents, fillers, crystal nucleating agents, and catalysts to adjust the curing reaction.

The adhesive according to the present invention is cured under a temperature condition of <NUM> to <NUM> after bonding the object to be bonded together, whereby the curing reaction of the adhesive progresses to provide a cured product. The application of the adhesive should not be specified; however, it is useful as an adhesive when laminating a plurality of base materials such as films to form a laminate.

The laminate according to the present invention is a laminate obtained by laminating a layer of the two-component curable adhesive according to the present invention between a first base material and a second base material. Specifically, when the two-component curable adhesive according to the present invention is a solvent type, a laminate can be obtained by applying the two-component curable adhesive to the first base material with a dry laminator, performing a drying step if necessary, attaching a second base material to the applied surface, and curing the adhesive layer by aging. When the two-component curable adhesive is a non-solvent type, a laminate can be obtained by using a non-sol laminator to heat a roll coater to typically <NUM> to <NUM> and using an adhesive with a blended viscosity of about <NUM> to <NUM>,<NUM> mPa·s at <NUM>.

The amount of the solid content in the adhesive applied is preferably <NUM> to <NUM>/m<NUM>, and more preferably <NUM> to <NUM>/m<NUM> for non-solvent type and <NUM> to <NUM>/m<NUM> for solvent type.

A film-like base material commonly used in a packaging material is preferable as the first base material. Examples of the first base material include a PET (polyethylene terephthalate) film, a NY (nylon) film, an OPP (biaxially oriented polypropylene) film, K-coated films including polyvinylidene chloride, base films such as various vapor-deposited films including silica vapor-deposited PET or alumina vapor-deposited PET, or an aluminum foil.

A film-like base material commonly used in a packaging material is preferable as the second base material. In addition to the base materials described in the first base material, examples of the second base material include: sealant films such as a CPP (unstretched polypropylene) film, a LLDPE (linear low density polyethylene), a LDPE (low density polyethylene), and a HDPE (high density polyethylene); and their aluminum vapor-deposited or silica vapor-deposited films.

Examples of the structure of the laminate according to the present invention include OPP/CPP, OPP/aluminum vapor-deposited CPP, Nylon/CPP, NY/LLDPE, PET/CPP, PET/aluminum vapor-deposited CPP, PET/aluminum vapor-deposited PET/CPP, PET/aluminum vapor-deposited PET/LLDPE, PET/NY/CPP, alumina vapor-deposited PET/NY/CPP, PET/aluminum/LLDPE, NY/aluminum/LLDPE, PET/aluminum/CPP, NY/aluminum/CPP, silica vapor-deposited PET/NY/LLDPE, alumina vapor-deposited PET/NY/CPP, and PET/NY/PET/NY/aluminum/CPP, and it can be appropriately selected depending on the application.

The laminate according to the present invention may further have a pattern layer. The pattern layer is a layer for forming optional desired printed patterns such as letters, numerals, patterns, graphics, symbols, and designs, and includes a solid printed layer, in order to add the beauty or displays such as decoration, display of contents, display of expiration date, display of manufacturer and seller, and other displays. The pattern layer can be formed by using conventionally known pigments and dyes, and the method for forming the pattern layer is not particularly limited.

The pattern layer is typically formed by using printing ink including a colorant such as pigment or dye.

A binder resin included in the ink is appropriately selected according to the application and base material, and examples thereof include a polyurethane resin, a polyurethane polyurea resin, a vinyl chloride-acrylate copolymer, a vinyl chloride-vinyl acetate copolymer, a chlorinated polypropylene resin, an ethylenevinyl acetate copolymer resin, a vinyl acetate resin, a polyamide resin, a nitrocellulose resin (nitrocellulose), an acrylic resin, a polyester resin, an alkyd resin, a polyvinyl chloride resin, a rosin resin, a rosin-modified maleic acid resin, a terpene resin, a phenol-modified terpene resin, a ketone resin, a cyclized rubber, a chlorinated rubber, a butyral, a petroleum resin, and a modified resin thereof.

A method for applying the printing ink is not particularly limited, and the printing ink can be applied by a gravure coating method, a flexo coating method, a roll coating method, a bar coating method, a die coating method, a curtain coating method, a spin coating method, an inkjet method, or the like. The printed layer can be formed by being allowed to stand, or if necessary, by air blowing, heating, drying under reduced pressure, irradiating with ultraviolet rays, or the like.

The pattern layer is a pattern layer having a thickness of preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, and still more preferably <NUM> or more and <NUM> or less.

The laminate according to the present invention can be mainly used as a packaging material (package) in the food, detergent, pharmaceutical, cosmetic, and toiletry industries. It can also be used as a secondary package for packaging a container consisting of the packaging material.

The present invention will be described in more detail below with reference to Examples and Comparative Examples. "Parts" and "%" in Examples and Comparative Examples mean "parts by mass" and "% by mass" unless otherwise specified.

An acid value was measured by the following procedure. First, about <NUM> of a sample (polyester polyol solution) was accurately weighed into a stoppered conical flask, and dissolved by adding <NUM> of a toluene/ethanol (volume ratio: toluene/ethanol = <NUM>/<NUM>) mixed solution. A phenolphthalein test solution was added thereto as an indicator and held for <NUM> seconds. Thereafter, the solution was titrated with a <NUM>. 1N alcoholic potassium hydroxide solution until it turned pink. The acid value was determined by the following formula: <MAT>.

A hydroxyl value was measured by the following procedure. First, about <NUM> of a sample (polyester polyol solution) was accurately weighed into a stoppered conical flask, and dissolved by adding <NUM> of a toluene/ethanol (volume ratio: toluene/ethanol = <NUM>/<NUM>) mixed solution. Exactly <NUM> of an acetylating agent (a solution of <NUM> of acetic anhydride dissolved in pyridine to a volume of <NUM>) was further added and stirred for about <NUM> hour. A phenolphthalein test solution was added thereto as an indicator and held for <NUM> seconds. Thereafter, the solution was titrated with a <NUM>. 1N alcoholic potassium hydroxide solution until it turned pink. The hydroxyl value was determined by the following formula (unit: mgKOH/g): <MAT>.

The number average molecular weight and weight average molecular weight were measured by using GPC (gel permeation chromatography) manufactured by Showa Denko K. with Shodex GPC LF-<NUM> (trade name, manufactured by Shodex Co. ) as a column and GPC with an RI detector (trade name GPC-<NUM> manufactured by Shodex Co. ), and using tetrohydrofuran as a solvent, and the values in terms of standard polystyrene were used.

A GC-8AFID type (hydrogen flame ionization detector) gas chromatography (column: 8G26-<NUM> (<NUM>) made of glass, filler: PEG-<NUM>) manufactured by Shimadzu Corporation was used to measure the amount of a residual solvent. First, a laminate cut to a size of <NUM><NUM> was finely cut, placed in a <NUM> flask, which was sealed with silicone rubber, and heated at <NUM> for <NUM> minutes, and the flask was removed from the oven and <NUM> of the sample was injected into the gas chromatography by using a gastight syringe. Using a previously obtained calibration curve, the amount of the residual solvent in the laminated sample was calculated, and the results were expressed in mg/m<NUM>.

<NUM> parts of a bifunctional polypropylene glycol of having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of tolylene diisocyanate, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were placed in a reaction vessel and heated at <NUM> to <NUM> for <NUM> to <NUM> hours while stirred under a nitrogen gas stream to perform an urethanization reaction. During the urethane reaction, <NUM>% of dibutyltin dilaurate (DBTDL) was added as a reaction catalyst to accelerate the reaction. After completion of the reaction, <NUM> phr of <NUM>-glycidoxypropyltrimethoxysilane was added and diluted with ethyl acetate to provide a solution of the polyether urethane polyol (A1) adjusted to have a non-volatile content of <NUM>%. The viscosity of the solution was <NUM>,<NUM> mPa·s at <NUM>. The weight average molecular weight was <NUM>,<NUM>.

<NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, and <NUM> parts of tolylene diisocyanate were placed in a reaction vessel and heated at <NUM> to <NUM> for <NUM> to <NUM> hours while stirred under a nitrogen gas stream to perform an urethanization reaction. During the urethane reaction, <NUM>% of dibutyltin dilaurate was added as a reaction catalyst to accelerate the reaction. After completion of the reaction, <NUM> phr of <NUM>-glycidoxypropyltrimethoxysilane was added and diluted with ethyl acetate to provide a solution of the polyether urethane polyol (A2) adjusted to have a non-volatile content of <NUM>%. The viscosity of the solution was <NUM>,<NUM> mPa·s at <NUM>. The weight average molecular weight was <NUM>,<NUM>.

<NUM> parts of a bifunctional polypropylene glycol of having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of tolylene diisocyanate, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were placed in a reaction vessel and heated at <NUM> to <NUM> for <NUM> to <NUM> hours while stirred under a nitrogen gas stream to perform an urethanization reaction. During the urethane reaction, <NUM>% of dibutyltin dilaurate was added as a reaction catalyst to accelerate the reaction, and after completion of the reaction, the resultant solution was diluted with ethyl acetate to provide a solution of the polyether urethane polyol (A3) adjusted to <NUM>% non-volatile content. The viscosity of the solution was <NUM>,<NUM> mPa·s at <NUM>. The weight average molecular weight was <NUM>,<NUM>.

<NUM> parts of isophthalic acid, <NUM> parts of sebacic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, <NUM> parts of neopentyl glycol, and <NUM> parts of <NUM>,<NUM>-hexanediol were charged to perform an esterification reaction at <NUM> to <NUM>. After distillation of the predetermined amount of water, gradual pressure reduction was performed and a deglycol reaction was performed for <NUM> hours at <NUM> to <NUM> under <NUM> hPA or less to provide a polyester polyol with a number average molecular weight of <NUM>,<NUM>, a mass-average molecular weight of <NUM>,<NUM>, a hydroxyl value of <NUM> mgKOH/g, and an acid value of <NUM> mgKOH/g. Furthermore, <NUM> parts of isophorone diisocyanate was gradually added to the total amount of this polyester polyol, and the reaction was performed at <NUM> for about <NUM> hours to provide a polyester urethane polyol having a number average molecular weight of <NUM>,<NUM>, a weight average molecular weight of <NUM>,<NUM>, a hydroxyl value of <NUM> mgKOH/g, and an acid value of <NUM> mgKOH/g. The obtained polyester urethane polyol was diluted with ethyl acetate to provide a solution of polyester urethane polyol (X1) having a non-volatile content of <NUM>%. The viscosity of the solution was <NUM> mPa·s at <NUM>.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (B1) having a number average molecular weight of <NUM> and an acid value of <NUM> mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (B2) having a number average molecular weight of <NUM>,<NUM> and an acid value of <NUM> mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (B3) having a number average molecular weight of <NUM>,<NUM> and an acid value of 20mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (B4) having a number average molecular weight of <NUM>,<NUM> and an acid value of 10mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (B5) having a number average molecular weight of <NUM>,<NUM> and an acid value of 35mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (B6) having a number average molecular weight of <NUM> and an acid value of <NUM> mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (B7) having a number average molecular weight of <NUM>,<NUM> and an acid value of 20mgKOH/g.

<NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of a trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were charged into a reaction vessel. An urethanization reaction was performed by heating at <NUM> to <NUM> for <NUM> to <NUM> hours while stirring under a nitrogen gas stream, and after completion of the reaction, the solution was diluted with ethyl acetate to <NUM>% non-volatile content to provide a solution of a polyether urethane polyisocyanate (C1). The isocyanate group content of (C1) was <NUM>% and the viscosity was <NUM>,<NUM> mPa·s at <NUM>.

<NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> part of a trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were charged into a reaction vessel. An urethanization reaction was performed by heating at <NUM> to <NUM> for <NUM> to <NUM> hours while stirring under a nitrogen gas stream, and after completion of the reaction, <NUM> parts of a trimethylolpropane adduct of tolylene diisocyanate was mixed and the solution was diluted with ethyl acetate to a non-volatile content of <NUM>% to provide a solution of a polyether urethane polyisocyanate (C2). The isocyanate group content of (C2) was <NUM>% and the viscosity was <NUM>,<NUM> mPa·s at <NUM>.

A trimethylolpropane adduct of <NUM>,<NUM>-xylylene diisocyanate (XDI) and a trimethylolpropane adduct of isophorone diisocyanate (IPDI) were blended at a solid content mass ratio of <NUM> : <NUM>, and the mixture was adjusted to a non-volatile content of <NUM>% with ethyl acetate to provide a solution of a polyisocyanate (C3). The isocyanate group content of (C3) was <NUM>% and the viscosity was <NUM> mPa·s at <NUM>.

The polyol component and the polyisocyanate component obtained in the above Synthesis Examples were blended in the amounts shown in Table <NUM> to adjust a two-component curable adhesive having a non-volatile content of <NUM>%.

Using the obtained adhesive, a laminate was produced and evaluated as follows. The results are shown in Table <NUM>.

Printing inks (Rio Alpha R39 Indigo, R631 White, manufactured by Toyo Ink Co. ) were each diluted with an ethyl acetate/IPA mixed solvent (mass ratio <NUM>/<NUM>) to a viscosity of <NUM> seconds (<NUM>, Zahn Cup No. <NUM>).

Each diluted printing ink was printed on a corona-treated OPP film (P-<NUM> (trade name) manufactured by Toyobo Co. , thickness <NUM>) in the order of indigo and white with a gravure proofreading two-color machine equipped with a solid plate having a plate depth of <NUM>. The printing speed was set to <NUM>/min, and drying was performed at <NUM> in each unit to provide a laminate of OPP/printed layer. The thickness of the printed layer was set to <NUM>.

On the printed layer of the obtained laminate, using a laminator, the adhesive obtained above was applied at a coating speed of <NUM>/min, and dried in a drying oven (<NUM>-<NUM>-<NUM> triple oven, furnace length <NUM>) to volatilize the solvent, and then the adhesive-applied surface was laminated with a <NUM>-thick VMCPP film (<NUM> (trade name) manufactured by Toray Advanced Film Co. , <NUM>-thick, aluminum vapor-deposited unstretched polypropylene) to provide a laminate (<NUM>-<NUM>). The solid content of the adhesive applied was set to <NUM>/m<NUM>.

A laminate (<NUM>-<NUM>) was obtained in the same manner as the laminate (<NUM>-<NUM>), except that the corona-treated OPP film was changed to a corona-treated PET film (E5102 (trade name) manufactured by Toyobo Co. , thickness <NUM>), the coating speed of the adhesive was changed from <NUM>/min to <NUM>/min, and the drying oven was changed to a <NUM>-<NUM>-<NUM> triple oven.

A laminate (<NUM>-<NUM>) was obtained in the same manner as the laminate (<NUM>-<NUM>), except that the VMCPP film was changed to a <NUM> thick VMPET film (Dialuster H27 (trade name) manufactured by REIKO Co. , <NUM> thick, aluminum vapor-deposited PET) and the coating speed of the adhesive was changed from <NUM>/min to <NUM>/min.

A laminate (<NUM>-<NUM>) was obtained in the same manner as the laminate (<NUM>-<NUM>), except that the coating speed of the adhesive was changed from <NUM>/min to <NUM>/min.

The amount of residual solvent in the laminate (<NUM>-<NUM>) was measured and evaluated according to the following criteria:.

The laminate (<NUM>-<NUM>) was stored at <NUM> for <NUM> hours to cure the adhesive. A test piece with a size of <NUM> × <NUM> was cut out from the cured laminate, and a tensile tester was used to perform T-type peeling at a temperature of <NUM> and a relative humidity of <NUM>% at a peel speed of <NUM>/min, and the lamination strength (N/<NUM>) between PET and VMCPP was measured. An average value of five test pieces was obtained and evaluated according to the following criteria:.

When visually observing the laminate appearance of three laminates (<NUM>-<NUM>) to (<NUM>-<NUM>) having coating speeds of <NUM>/min, <NUM>/min, and <NUM>/min, respectively, the case where no appearance defect such as a spotted pattern occurred was designated as A, the case where the appearance defect was very slightly observed was designated as B, and the case where the appearance defect was observed was designated as C (except for the evaluation B). The results of the three laminates were integrated and evaluated according to the following criteria:.

According to Table <NUM>, the adhesive according to the present invention including <NUM> to <NUM> parts of the polyester polyol (B) having a number average molecular weight of <NUM> to <NUM>,<NUM> based on <NUM> parts of polyether urethane polyol (A) is excellent in adhesion force and good in lamination appearance without coating unevenness at high speed coating of <NUM>/min, and had a reduced amount of residual solvent.

In particular, when the acid value of the polyester polyol (B) was in the range of <NUM> to <NUM> mgKOH/g, the adhesion strength to the aluminum vapor-deposited film and the high speed coatability were excellent.

Furthermore, the laminate using a polyether urethane polyisocyanate, which is a reaction product of an aromatic diisocyanate and a polyether polyol, was excellent in lamination strength.

A bifunctional polypropylene glycol of <NUM> parts having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of dipropylene glycol, and <NUM> parts of tolylene diisocyanate were placed in a reaction vessel and heated at <NUM> to <NUM> for <NUM> to <NUM> hours while stirred under a nitrogen gas stream to perform an urethanization reaction. During the urethane reaction, <NUM>% of dibutyltin dilaurate (DBTDL) was added as a reaction catalyst to accelerate the reaction, and after completion of the reaction, the resultant solution was diluted with ethyl acetate to provide a solution of the polyether urethane polyol (AY1) adjusted to <NUM>% non-volatile content. The solution had a viscosity of <NUM>,<NUM> mPa·s at <NUM> and a weight average molecular weight of <NUM>,<NUM>.

A bifunctional polypropylene glycol of <NUM> parts having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of tolylene diisocyanate, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were placed in a reaction vessel and heated at <NUM> to <NUM> for <NUM> to <NUM> hours while stirred under a nitrogen gas stream to perform an urethanization reaction. During the urethane reaction, <NUM>% of dibutyltin dilaurate was added as a reaction catalyst to accelerate the reaction, and after completion of the reaction, the resultant solution was diluted with ethyl acetate to provide a solution of the polyether urethane polyol (AY2) adjusted to <NUM>% non-volatile content. The solution had a viscosity of <NUM>,<NUM> mPa·s at <NUM> and a weight average molecular weight of <NUM>,<NUM>.

A bifunctional polypropylene glycol of <NUM> parts having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, and <NUM> parts of tolylene diisocyanate were placed in a reaction vessel and heated at <NUM> to <NUM> for <NUM> to <NUM> hours while stirred under a nitrogen gas stream to perform an urethanization reaction. During the urethane reaction, <NUM>% of dibutyltin dilaurate was added as a reaction catalyst to accelerate the reaction, and after completion of the reaction, the resultant solution was diluted with ethyl acetate to provide a solution of the polyether urethane polyol (AY3) adjusted to <NUM>% non-volatile content. The viscosity of the solution was <NUM>,<NUM> mPa·s at <NUM>. The weight average molecular weight was <NUM>,<NUM>.

In the same manner as in Synthesis Example <NUM>, a solution of a polyester urethane polyol (X1) having a non-volatile content of <NUM>% was obtained.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (BY1) having a number average molecular weight of <NUM>,<NUM> and an acid value of 25mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (BY2) having a number average molecular weight of <NUM>,<NUM> and an acid value of <NUM> mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (BY3) having a number average molecular weight of <NUM>,<NUM> and an acid value of <NUM> mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (BY4) having a number average molecular weight of <NUM>,<NUM> and an acid value of <NUM> mgKOH/g.

<NUM> parts of isophthalic acid, <NUM> parts of adipic acid, <NUM> parts of ethylene glycol, and <NUM> parts of <NUM>,<NUM>-butanediol were charged to perform an esterification reaction at <NUM> to <NUM> for <NUM> hours. After distillation of a predetermined amount of water, <NUM> parts of tetraisobutyl titanate was added, the pressure was gradually reduced, the mixed solution was heated at <NUM> to <NUM> hPa and <NUM> to <NUM> for <NUM> hours to distill off a part of the glycol component, and transesterification reaction was performed to obtain a polyester polyol. <NUM> parts of trimellitic anhydride was added to the total amount of this polyester polyol to provide an acid-modified polyester polyol (BY5) having a number average molecular weight of <NUM>,<NUM> and an acid value of <NUM> mgKOH/g.

<NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> part of trifunctional trimethylolpropane, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were charged into a reaction vessel. An urethanization reaction was performed by heating at <NUM> to <NUM> for <NUM> to <NUM> hours while stirring under a nitrogen gas stream, and after completion of the reaction, the solution was diluted with ethyl acetate to <NUM>% non-volatile content to provide a solution of a polyether urethane polyisocyanate (CY1). The isocyanate group content of (CY1) was <NUM>% and the viscosity was <NUM>,<NUM> mPa·s at <NUM>.

<NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of a trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were charged into a reaction vessel. An urethanization reaction was performed by heating at <NUM> to <NUM> for <NUM> to <NUM> hours while stirring under a nitrogen gas stream. After completion of the reaction, <NUM> parts of a trimethylolpropane adduct of tolylene diisocyanate were mixed and diluted with ethyl acetate to a non-volatile content of <NUM>% to provide a solution of polyether urethane polyisocyanate (CY2). The isocyanate group content of (CY2) was <NUM>% and the viscosity was <NUM>,<NUM> mPa·s at <NUM>.

<NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>,<NUM>, <NUM> parts of a bifunctional polypropylene glycol having a number average molecular weight of about <NUM>, <NUM> parts of a trifunctional polypropylene glycol having a number average molecular weight of about <NUM>, and <NUM> parts of <NUM>,<NUM>'-diphenylmethane diisocyanate were charged into a reaction vessel. An urethanization reaction was performed by heating at <NUM> to <NUM> for <NUM> to <NUM> hours while stirring under a nitrogen gas stream, and after completion of the reaction, the solution was diluted with ethyl acetate to <NUM>% non-volatile content to provide a solution of a polyether urethane polyisocyanate (CY3). The isocyanate group content of (CY3) was <NUM>% and the viscosity was <NUM>,<NUM> mPa·s at <NUM>.

A trimethylolpropane adduct of <NUM>,<NUM>-xylylene diisocyanate (XDI) and a trimethylolpropane adduct of isophorone diisocyanate (IPDI) were blended at a solid content ratio of <NUM> : <NUM>, and the mixture was adjusted to a non-volatile content of <NUM>% with ethyl acetate to provide a solution of a polyisocyanate (CY4). The isocyanate group content of (CY4) was <NUM>% and the viscosity was <NUM> mPa·s at <NUM>.

A polyol, a polyisocyanate, a hydroxy acid having two carboxyl groups, and a silane coupling agent were mixed and stirred according to the composition shown in Tables <NUM> and <NUM> to produce a two-component curable adhesive.

Using the obtained adhesive, the following laminates were produced and evaluated. The results are given in Table <NUM> and Table <NUM>.

Printing inks (manufactured by Toyo Ink Co. , RV-R <NUM> red/<NUM> white, nitrocellulose/urethane ink) were each diluted with a solvent to a viscosity of <NUM> seconds (<NUM>. , Zahn cup No. <NUM>).

Each diluted printing ink was printed in the red-white order of red and white on a corona-treated OPP film (P-<NUM> (trade name) manufactured by Toyobo Co. , thickness <NUM>) with a flexo proofing <NUM>-color machine equipped with a solid plate. The printing speed was set to <NUM>/min, and drying was performed at <NUM> in each unit to provide a laminate of OPP/printed layer. The thickness of the printed layer was set to <NUM>.

On the printed layer of the obtained laminate, using a laminator, the obtained adhesive was applied at a coating speed of <NUM>/min, and dried in a drying oven (<NUM>-<NUM>-<NUM> triple oven, furnace length <NUM>) to volatilize the solvent, and then the adhesive-applied surface was laminated with a VMCPP film (<NUM> (trade name) manufactured by Toray Advanced Film Co. , <NUM>-thick, aluminum vapor-deposited unstretched polypropylene) to provide a laminate (<NUM>-<NUM>). The solid content of the adhesive applied was set to <NUM>/m<NUM>.

Printing inks (Rio Alpha R39 indigo/R631 white, urethane ink, manufactured by Toyo Ink Co. ) were each diluted with a mixed solvent to a viscosity of <NUM> seconds (<NUM>, Zahn cup No. <NUM>). Each diluted printing ink was printed on a corona-treated OPP film (P-<NUM> (trade name) manufactured by Toyobo Co. , thickness <NUM>) in the indigo-white order of indigo and white with a gravure proofreading two-color machine equipped with a solid plate. The printing speed was set to <NUM>/min, and drying was performed at <NUM> in each unit to provide a laminate of OPP/printed layer. The thickness of the printed layer was set to <NUM>.

On the printed layer of the obtained laminate, using a laminator, the obtained adhesive was applied at a coating speed of <NUM>/min, and dried in a drying oven (<NUM>-<NUM>-<NUM> triple oven, furnace length <NUM>) to volatilize the solvent, and then the adhesive-applied surface was laminated with a VMCPP film (<NUM> manufactured by Toray Advanced Film Co. , <NUM>-thick, aluminum vapor-deposited unstretched polypropylene) to provide a laminate (<NUM>-<NUM>). The solid content of the adhesive applied was set to <NUM>/m<NUM>.

A laminate (<NUM>-<NUM>) was obtained in the same manner as the laminate (<NUM>-<NUM>), except that the corona-treated OPP film was changed to a corona-treated PET film (E5102 (trade name) manufactured by Toyobo Co. , thickness <NUM>), and aluminum foil (manufactured by Toyo Aluminium K. , thickness <NUM>) and LLDPE film (Tocello TUX-FCD manufactured by Mitsui Chemicals, Inc. , thickness <NUM>) were laminated on a printed layer using the obtained adhesive in a drying oven (<NUM>-<NUM>-<NUM> triple oven) at a coating speed of <NUM>/min.

The laminates (<NUM>-<NUM>) and (<NUM>-<NUM>) were stored at <NUM> for <NUM> hours to cure the adhesive. A test piece with a size of <NUM> × <NUM> was cut out from the cured laminate, and a tensile tester was used to perform T-type peeling at a temperature of <NUM> and a relative humidity of <NUM>% at a peel speed of <NUM>/min, and the adhesive strength (N/<NUM>) between OPP and VMCPP was measured. An average value of five test pieces was obtained and evaluated according to the following criteria:.

The laminates (<NUM>-<NUM>) and (<NUM>-<NUM>) were stored at <NUM> for <NUM> hours to cure the adhesive, and then they were further stored in an environment of <NUM> and humidity of <NUM>% for one month. Using the laminate after storage, the adhesive strength was measured in the same manner as [Adhesive strength between OPP and VMCPP (at initial stage)], the average value of five test pieces was obtained, and evaluated according to the following criteria:.

The laminates (<NUM>-<NUM>) and (<NUM>-<NUM>) were stored at <NUM> for <NUM> hours to cure the adhesive. A test piece with a size of <NUM> × <NUM> was cut out from the cured laminate, and a tensile tester was used to perform T-type peeling at a temperature of <NUM> and a relative humidity of <NUM>% at a peel speed of <NUM>/min, and the adhesive strength (N/<NUM>) between PET and VMCPP was measured. An average value of five test pieces was obtained and evaluated according to the following criteria:.

The laminates (<NUM>-<NUM>) and (<NUM>-<NUM>) were stored at <NUM> for <NUM> hours to cure the adhesive, and then they were further stored in an environment of <NUM> and humidity of <NUM>% for one month. Using the laminate after storage, the adhesive strength was measured in the same manner as [Adhesive strength between PET, AL, and LLDPE (at initial stage)], the average value of five test pieces was obtained, and evaluated according to the following criteria:.

The amount of residual solvent in the laminates (<NUM>-<NUM>) and (<NUM>-<NUM>) was measured and evaluated according to the following criteria:.

The three laminates (<NUM>-<NUM>), (<NUM>-<NUM>), and (<NUM>-<NUM>) with different coating speeds were visually observed for the appearance of each laminate, and the case where no appearance defect such as a spotted pattern occurred was designated as A, the case where the appearance defect was very slightly observed was designated as B, and the case where the appearance defect was observed was designated as C (except for the evaluation B). The results of the three laminates were integrated and evaluated according to the following criteria:.

Table <NUM> indicated that the adhesive according to the present invention including a hydroxy acid having two carboxyl groups was excellent in laminate appearance at a high speed coating of <NUM>/min or more, and the residual solvent was reduced. Furthermore, without using a silane coupling agent, excellent adhesive strength was exhibited when using ink containing a urethane resin or a nitrocellulose resin as a binder component.

Claim 1:
A two-component curable adhesive comprising:
a polyol component; and
a polyisocyanate component,
wherein the polyol component comprises a polyether urethane polyol (A) and a polyester polyol (B) having a number average molecular weight of <NUM> to <NUM>,<NUM>, and
a content of the polyester polyol (B) is <NUM> to <NUM> parts by mass based on <NUM> parts by mass of the polyether urethane polyol (A).