Reactive adhesives, laminates and packaging

Abstract

To provide a reactive adhesive which is excellent in adhesive force to metal without using a silane coupling agent and adhesive force in the case of using nitrocellulose resin-based ink, prevents coating unevenness in high speed coating, and has a reduced residual solvent, and a laminate and a package which are excellent in adhesive force to metal and adhesive force in the case of using nitrocellulose resin-based ink, have good appearance and have a reduced residual solvent.SOLUTION: A reactive adhesive contains a polyisocyanate compound and a polyol compound, wherein the polyisocyanate compound contains polyurethane polyisocyanate (A) that is a reaction product of aromatic polyisocyanate (a1) and polyol (a2) having an ether bond, the polyol compound contains polyester polyol (B) having an acid value of 10-50 mgKOH / g, and a peak area ratio V in ATR-FTIR method of the cured product satisfies a relation of 0.90≤V≤1.10.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a reactive adhesive, and a laminate and a package using the adhesive, and more particularly to a reactive adhesive useful as a packaging material for foods, medicines, cosmetics, etc., and a laminate and a package using the adhesive. [Background technology]

[0002] Laminates formed by laminating various plastic films together or a plastic film with a metallized film or metal foil via an adhesive layer are used as flexible packaging materials for packaging contents such as food, medicines, and cosmetics. Two-component curing reactive adhesives that utilize a urethane reaction between the hydroxyl groups of a polyol and the isocyanate groups of a polyisocyanate are widely used as adhesives for forming the adhesive layer. However, in recent years, the use of plastic films with low surface treatment levels has increased in order to reduce costs, and further improvements in the adhesive strength of adhesives are required. For example, adhesives using polyester polyols are known as adhesives with excellent adhesive strength. However, because polyester polyols have high affinity with diluting solvents and poor solvent releasability, when polyester polyols are used as the main component resin, problems such as poor appearance and residual solvent are likely to occur when high-speed coating is performed, for example, at 200 m / min or more. To address the above problems, for example, Patent Documents 1 and 2 describe that adhesives using polyether urethane polyols suppress the degree of viscosity increase and are excellent in coatability and residual solvent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-306931 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-306932 Summary of the Invention [Problem to be solved by the invention]

[0004] However, adhesives using polyether urethane polyols have the problem that their adhesive strength with metal-deposited films or metal foils, as well as their adhesive strength when coated onto a printing ink layer containing nitrocellulose resin (nitrocellulose nitrate) as a binder component, is significantly reduced. Furthermore, in recent years, there has been growing interest in the hygiene aspects of food ingredients, particularly in Europe, and efforts are being made to reduce the use of additives such as silane coupling agents, which have been used to improve metal adhesion and heat resistance. However, at present, it is difficult to obtain an adhesive that has excellent coatability and residual solvent during high-speed coating, and that also has excellent adhesive strength and metal adhesion when coated onto a printing ink layer containing a nitrocellulose resin as a binder component, even without using a silane coupling agent. Therefore, an object of the present invention is to provide a reactive adhesive that has excellent adhesive strength with metal-deposited films or metal foils even without the use of a silane coupling agent, and that has excellent adhesive strength when used with printing inks containing nitrocellulose resin as a binder component, and that does not cause coating unevenness during high-speed coating and has little residual solvent. Another object of the present invention is to provide a laminate and a package that have excellent adhesive strength to a metal-deposited film or metal foil, and excellent adhesive strength when used with a printing ink containing a nitrocellulose resin as a binder component, and that have a good appearance and little residual solvent. [Means for solving the problem]

[0005] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by a reactive adhesive comprising a polyisocyanate compound containing a specified polyurethane polyisocyanate and a polyol compound containing a polyester polyol having a specified acid value, wherein the cured product has a peak area ratio V of 0.90≦V≦1.10 as measured by ATR-FTIR. This finding led to the present invention.

[0006] A reactive adhesive according to one embodiment of the present invention is a reactive adhesive comprising a polyisocyanate compound and a polyol compound, wherein the polyisocyanate compound comprises a polyurethane polyisocyanate (A) which is a reaction product of an aromatic polyisocyanate (a1) and a polyol (a2) having an ether bond, and the polyol compound comprises a polyester polyol (B) having an acid value in the range of 10 to 50 mgKOH / g, and the cured product of the reactive adhesive has a peak area ratio V of 0.90≦V≦1.10 as measured by an ATR-FTIR method. The peak area ratio V is calculated as follows: <1> ~ <3> This is obtained by the following procedure. <1> Solids application rate of 2.5 g / m on aluminum substrate 2 After the solvent is evaporated, the film is laminated to the untreated surface of a non-oriented polypropylene film and cured at 40°C and 60% RH for 3 days. <2> The unstretched polypropylene film was peeled off, and the exposed reactive adhesive cured product was measured at a location 1 to 2 μm from the surface toward the substrate using the ATR-FTIR method at a wave number of 1075 cm -1 ~1150cm -1 The absorbance peak area v1 at the wavenumber 1715 cm -1 ~1750cm -1 The absorbance peak area v2 at <3> The peak area ratio V is calculated from v1 and v2 using the following formula (1). Peak area ratio V = peak area v1 / peak area v2 (1)

[0007] A reactive adhesive according to one aspect of the present invention is characterized in that the aromatic polyisocyanate (a1) is diphenylmethane diisocyanate or a derivative thereof.

[0008] A reactive adhesive according to one aspect of the present invention is characterized in that the polyol (a2) contains a polyalkylene glycol.

[0009] A reactive adhesive according to one aspect of the present invention is characterized in that the polyurethane polyisocyanate (A) has a weight average molecular weight in the range of 5,000 to 20,000.

[0010] The reactive adhesive according to one aspect of the present invention is characterized in that the polyester polyol (B) has a weight average molecular weight in the range of 1,000 to 3,000.

[0011] A laminate according to one aspect of the present invention is characterized in that it comprises a cured product of the reactive adhesive between a first substrate and a second substrate.

[0012] A laminate according to one embodiment of the present invention is a laminate comprising an adhesive layer, which is a cured product of a reactive adhesive, between a first substrate and a second substrate, wherein the reactive adhesive comprises a polyisocyanate compound and a polyol compound, the polyisocyanate compound comprises a polyurethane polyisocyanate (A) which is a reaction product of an aromatic polyisocyanate (a1) and a polyol (a2) having an ether bond, the polyol compound comprises a polyester polyol (B) having an acid value in the range of 10 to 50 mgKOH / g, and the peak area ratio V of the adhesive layer measured by an ATR-FTIR method is 0.90≦V≦1.10. The peak area ratio V is calculated as follows: <4> ~ <5> This is obtained by the following procedure. <4> The first substrate and the second substrate are peeled off, and a portion of the exposed cured reactive adhesive 1 to 2 μm from the surface toward the substrate is analyzed by ATR-FTIR at a wave number of 1075 cm -1 ~1150cm -1 The absorbance peak area v1 at 1715 cm -1 ~1750cm -1 The absorbance peak area v2 at <5> The peak area ratio V is calculated from v1 and v2 using the following formula (1). Peak area ratio V = peak area v1 / peak area v2 (1)

[0013] A packaging body according to one aspect of the present invention is characterized by using the above-described laminate. [Effects of the Invention]

[0014] The present invention can provide a reactive adhesive that has excellent adhesive strength to metal-deposited films or metal foils and when used with printing inks containing nitrocellulose resins as binders, even without the use of a silane coupling agent, does not cause coating unevenness in high-speed coating, and has little residual solvent.The present invention can also provide laminates and packages that have excellent adhesive strength to metal-deposited films or metal foils and when used with printing inks containing nitrocellulose resins as binders, have good appearances, and have little residual solvent. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Reactive adhesive> The reactive adhesive of the present invention comprises a polyisocyanate compound and a polyol compound, the polyisocyanate compound comprising a polyurethane polyisocyanate (A) which is a reaction product of an aromatic polyisocyanate (a1) and a polyol (a2) having an ether bond, and the polyol compound comprising a polyester polyol (B) having an acid value in the range of 10 to 50 mgKOH / g. The reactive adhesive of the present invention also has a peak area ratio V of 0.90≦V≦1.10 when measured by an ATR-FTIR method for a cured product of the reactive adhesive. In laminates such as packaging materials, the nitrocellulose and additives contained in the ink layer can permeate (hereinafter referred to as migration) from the ink layer into the adhesive layer and remain at the interface between the adhesive layer and the substrate, resulting in a decrease in adhesive strength over time. Furthermore, polyether skeletons are prone to migration. However, by combining a polyester polyol (B) having an acid value in the range of 10 to 50 mgKOH / g with a polyurethane polyisocyanate (A) which is a reaction product of an aromatic polyisocyanate (a1) and a polyol (a2) having an ether bond, the adhesive contains both ester bonds and ether bonds, and the characteristics of both can be exhibited. Furthermore, the peak area v1 is derived from ether bonds, the peak area v2 is derived from ester bonds, and the peak area ratio V refers to the ratio of ester bonds to ether bonds. In other words, by controlling the peak area ratio V within a certain range, it is possible to control the voids in the three-dimensional network structure in the cured product of the reactive adhesive, and even without using a silane coupling agent, the adhesive has excellent adhesion to metal-deposited films or metal foils and nitrocellulose resin-based printing inks, and can suppress coating unevenness and residual solvent in high-speed coating. Specifically, the polyester bonds in the hard segments densify the three-dimensional network structure, thereby demonstrating high adhesive performance. Meanwhile, the polyether bonds in the soft segments allow for the introduction of appropriate gaps into the three-dimensional network structure, thereby achieving not only excellent high-speed coatability due to low viscosity but also excellent solvent desorption. Furthermore, by controlling the peak area ratio V within the range of 0.90≦V≦1.10, a three-dimensional network structure in which high-density and low-density network structures are distributed over a certain range can be formed. As a result, the polymer maintains high adhesive strength, excels in high-speed coatability, and reduces residual solvent.

[0016] To achieve excellent adhesive strength over time, laminate appearance during high-speed coating, and reduced residual solvent, it is important that V be 0.90≦V≦1.10. If V is less than 0.90, the amount of residual solvent in the laminate increases, resulting in poor appearance. If V exceeds 1.10, adhesive strength over time decreases. From the viewpoint of the balance between adhesive performance and coating performance, a more preferable range is 0.92≦V≦1.00.

[0017] The peak area ratio V is given by <1> ~ <3> It can be obtained by the following procedure. <1> Solids application rate of 2.5 g / m on aluminum substrate 2 After the solvent is evaporated, the film is laminated to the untreated surface of a non-oriented polypropylene film and cured at 40°C and 60% RH for 3 days. <2> The unstretched polypropylene film was peeled off, and the exposed reactive adhesive cured product was measured at a location 1 to 2 μm from the surface toward the substrate using the ATR-FTIR method at a wave number of 1075 cm -1 ~1150cm -1 The absorbance peak area v1 at the wavenumber 1715 cm -1 ~1750cm -1 The absorbance peak area v2 at <3> The peak area ratio V is calculated from v1 and v2 using the following formula (1). Peak area ratio V = peak area v1 / peak area v2 (1)

[0018] An aluminum substrate and an untreated surface of an unstretched polypropylene film are bonded together via a reactive adhesive, the reactive adhesive is cured, and then the unstretched polypropylene film is peeled off, resulting in peeling between the cured layer of the reactive adhesive and the unstretched polypropylene film, and a test piece comprising the cured reactive adhesive on the aluminum substrate can be obtained.

[0019] In addition, in the case of a laminate having an adhesive layer, which is a cured product of a reactive adhesive, between a first substrate and a second substrate, the peak area ratio V of the adhesive layer is <4> ~ <5> It can be obtained by the following procedure. <4> The first substrate and the second substrate are peeled off, and a portion of the exposed cured reactive adhesive 1 to 2 μm from the surface toward the substrate is analyzed by ATR-FTIR at a wave number of 1075 cm -1 ~1150cm -1 The absorbance peak area v1 at the wavenumber 1715 cm -1 ~1750cm -1 The absorbance peak area v2 at <5> The peak area ratio V is calculated from v1 and v2 using the following formula (1). Peak area ratio V = peak area v1 / peak area v2 (1)

[0020] In addition, the ATR-FTIR method can obtain an infrared absorption spectrum of the surface of a sample by placing the sample in contact with a prism with a high refractive index, such as diamond. From the absorbance of the obtained absorption spectrum, the peak areas v1 and v2 can be calculated. The method for measuring absorbance by the ATR-FTIR method is, for example, to measure absorbance in the wavenumber range of 400 to 4000 cm at a position 1 to 2 μm from the surface of the cured product toward the substrate using an ATR-FT-IR ALPHA device manufactured by BRUKER. -1 , resolution 4cm -1 Measurement can be performed under the condition of 16 scans. Then, from the obtained infrared absorption spectrum, the peak area tool was used to find the peak at wavenumber 1075 cm -1 ~1150cm -1 The peak area v1 of the absorbance due to the ether bond, which has an absorption maximum in the region of 1715 cm -1 ~1750cm -1 The peak area v2 of the absorbance derived from the ester bond having an absorption maximum in the region of

[0049] can be calculated. The baseline was set as a line connecting the bottoms of both ends of the absorption curve where a peak exists or the valley between other absorption curves. Next, the peak area ratio V was calculated by the above formula (1), where V was the average value of six arbitrary points calculated from the same sample.

[0021] <Polyisocyanate compounds> The polyisocyanate compound constituting the reactive adhesive of the present invention contains a polyurethane polyisocyanate (A) which is a reaction product of an aromatic polyisocyanate (a1) and a polyol (a2) having an ether bond. Because the polyurethane polyisocyanate (A) has an ether bond derived from the polyol (a2), it may be abbreviated as polyetherurethane polyisocyanate.

[0022] [Polyurethane polyisocyanate (A)] The polyurethane polyisocyanate (A) can be obtained by subjecting a polyisocyanate component containing an aromatic polyisocyanate (a1) and a polyol component containing a polyol (a2) having an ether bond to a urethanization reaction using a known method under conditions of excess isocyanate groups. These polyurethane polyisocyanates (A) can be used alone or in combination of two or more.

[0023] (Aromatic polyisocyanate (a1)) Examples of the aromatic polyisocyanate (a1) include aromatic diisocyanates such as diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, phenylene diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate; aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate; and modified products of these polyisocyanates. Examples of modified polyisocyanates include allophanate-type modified polyisocyanates, isocyanates, Examples of modified polyisocyanates include late-type modified polyisocyanates, biuret-type modified polyisocyanates, and adduct-type modified polyisocyanates.

[0024] These aromatic polyisocyanates (a1) may be used singly or in combination of two or more. From the viewpoint of adhesive strength and curing speed, the aromatic polyisocyanate (a1) is preferably diphenylmethane diisocyanate or a derivative thereof.

[0025] (Polyol (a2) having an ether bond) The polyol (a2) having an ether bond may be any compound having two or more hydroxyl groups and two or more ether bonds in the molecule. Examples of such polyols (a2) 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. Alternatively, an addition polymer obtained by addition polymerization of an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran to a low-molecular-weight polyol such as water, ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, or sucrose (for example, a propylene glycol propylene oxide adduct, a glycerin propylene oxide adduct, a sorbitol-based propylene oxide adduct, or a sucrose-based propylene oxide adduct) may be used as the polyol (a2) having an ether bond.

[0026] The polyol (a2) may also be a polyester polyol, which is a reaction product of a polyhydric alcohol and a polycarboxylic acid. In this case, at least one of the polyhydric alcohol and / or the polycarboxylic acid may have an ether bond. Preferably, the polyhydric alcohol has an ether bond. Examples of such polyhydric alcohols include ether glycols such as diethylene glycol, triethylene glycol, polytetramethylene ether glycol, and polyoxyethylene glycol; and modified polyether diols obtained by ring-opening polymerization of an aliphatic diol such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3,3'-dimethylolheptane, or 1,4-bis(hydroxymethyl)cyclohexane with a cyclic ether bond-containing compound such as ethylene oxide or tetrahydrofuran. Among these, from the viewpoint of adhesive strength, the polyhydric alcohol having an ether bond is preferably one containing diethylene glycol.

[0027] Such polyester polyol having an ether bond may be a polyester urethane polyol in which a urethane bond is introduced by reacting a polyisocyanate with a hydroxyl group in the polyol. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate.

[0028] These polyols (a2) having an ether bond may be used singly or in combination of two or more. From the viewpoint of adhesive strength, the polyol (a2) having an ether bond preferably contains a polyalkylene glycol, more preferably a polypropylene glycol, and the weight-average molecular weight of the polyalkylene glycol is preferably 100 or more and 10,000 or less, more preferably 300 or more and 5,000 or less. From the viewpoint of resin compatibility, the polyol (a2) having an ether bond may contain, in addition to the polyalkylene glycol, a polyester polyol having an ether bond. From the viewpoint of adhesive strength and curing speed, the polyester polyol may be a polyester urethane polyol into which a urethane bond has been introduced by reacting with a polyisocyanate.

[0029] That is, the polyurethane isocyanate (A) is preferably a reaction product of a polyol component containing a polyalkylene glycol having a weight average molecular weight of 100 to 5,000 and a polyisocyanate component containing diphenylmethane diisocyanate or a derivative thereof. In addition, the polyurethane isocyanate (A) may also suitably be a reaction product of a polyol component containing a polyalkylene glycol having a weight average molecular weight of 100 to 5,000 and a polyester polyol or polyester urethane polyol having an ether bond, and a polyisocyanate component containing diphenylmethane diisocyanate or a derivative thereof.

[0030] The weight average molecular weight of the polyurethane isocyanate (A) used in the present invention is preferably 5,000 to 20,000. A weight average molecular weight in the above range is preferred from the viewpoint of resin compatibility and coating performance. The number average molecular weight and weight average molecular weight in this specification are values ​​measured using GPC (gel permeation chromatography) manufactured by Showa Denko KK, using tetrahydrofuran as a solvent, and converted into standard polystyrene.

[0031] The NCO content of the polyurethane polyisocyanate (A) is preferably from 3 to 8 mass %, more preferably from 4 to 6 mass %, from the viewpoints of adhesive performance and curing speed.

[0032] The polyisocyanate component constituting the polyurethane polyisocyanate (A) may contain a polyisocyanate other than the aromatic polyisocyanate (a1) within the range not impairing the effects of the present invention. Also, the polyol component constituting the polyurethane polyisocyanate (A) may contain a polyol other than the polyol (a2) having an ether bond within the range not impairing the effects of the present invention.

[0033] [Other polyisocyanates] The polyisocyanate compound used in the present invention may contain other polyisocyanates besides the polyurethane isocyanate (A) to the extent that the curing effect of the present invention is not impaired. Examples of other polyisocyanates that may be contained include aromatic polyisocyanates, araliphatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and modified products of these polyisocyanates.

[0034] Examples of aromatic polyisocyanates 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.

[0035] Examples of the araliphatic polyisocyanate include araliphatic diisocyanates such as 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω,ω′-diisocyanato-1,4-diethylbenzene, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene or a mixture thereof.

[0036] Examples of the aliphatic polyisocyanate include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate, lysine diisocyanate, and dimer acid diisocyanate.

[0037] Examples of alicyclic polyisocyanates include alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), methyl 2,4-cyclohexane diisocyanate, methyl 2,6-cyclohexane diisocyanate, 1,4-bis(isocyanatemethyl)cyclohexane, 1,3-bis(isocyanatemethyl)cyclohexane, and norbornene diisocyanate.

[0038] Examples of modified polyisocyanates include allophanate-type modified polyisocyanates, isocyanurate-type modified polyisocyanates, biuret-type modified polyisocyanates, and adduct-type modified polyisocyanates.

[0039] <Polyol compounds> The polyol compound constituting the reactive adhesive of the present invention contains a polyester polyol (B) having an acid value in the range of 10 to 50 mgKOH / g.

[0040] [Polyester polyol (B) having an acid value of 10 to 50 mgKOH / g] The polyester polyol (B) may be selected from known polyester polyols as long as it has two or more hydroxyl groups and two or more ester bonds in the molecule and has an acid value in the range of 10 to 50 mgKOH / g. One type of polyester polyol (B) may be used alone, or two or more types may be used in combination.

[0041] Examples of the polyester polyol (B) include polyester polyols obtained by reacting a polycarboxylic acid with a polyhydric alcohol; and polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone). Examples of the polycarboxylic acid 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, or dialkyl esters thereof, or mixtures thereof. Examples of the polyhydric alcohol include diols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, dineopentyl glycol, trimethylolpropane, glycerin, 1,6-hexanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 3,3′-dimethylolheptane, 1,9-nonanediol, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, polyether polyol, polycarbonate polyol, polyolefin polyol, acrylic polyol, and polyurethane polyol, or mixtures thereof. These polycarboxylic acids and polyhydric alcohols may be used singly or in combination of two or more.

[0042] The polyester polyol (B) may be a polyester urethane polyol in which urethane bonds are introduced by reacting a polyisocyanate with a hydroxyl group in the polyol. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate.

[0043] It is also important that the polyester polyol (B) has an acid value in the range of 10 to 50 mgKOH / g. An acid value of 10 mgKOH / g or more provides excellent adhesion to inks containing nitrocellulose resin as a binder, and to metal vapor deposition layers and metal foils. An acid value of 50 mgKOH / g or less provides excellent suitability for high-speed coating. The acid value of the polyester polyol (B) is preferably 20 to 50 mgKOH / g, more preferably 20 to 30 mgKOH / g. When the polyester polyol (B) contains a plurality of polyester polyols, the acid value of the polyester polyol (B) can be determined from the acid value of each polyester polyol and the mass ratio thereof.

[0044] From the viewpoint of having an acid value, the polyester polyol (B) is preferably one in which carboxy groups have been introduced (also referred to as acid modification) by reacting some of the hydroxyl groups in the polyol with an acid anhydride. Examples of the acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic ester anhydride. Examples of the trimellitic ester anhydride include ester compounds obtained by esterifying alkylene glycol or alkanetriol having 2 to 30 carbon atoms with trimellitic anhydride, and specific examples include ethylene glycol bisanhydrotrimellitate and propylene glycol bisanhydrotrimellitate.

[0045] The polyester polyol (B) is more preferably an acid-modified polyester polyol obtained by reacting an acid anhydride with part of the hydroxyl groups of a polyester polyol, which is a reaction product of a polycarboxylic acid and a polyhydric alcohol. The polyhydric alcohol may contain 30 to 70 mol % of 1,4-butanediol based on 100 mol of the total polyhydric alcohol. By using a polyester polyol made from such a polyhydric alcohol, it is possible to obtain an adhesive composition that has excellent adhesive strength, does not cause coating unevenness even when applied at high speed, and has little residual solvent.

[0046] The weight-average molecular weight of the polyester polyol (B) is not particularly limited, but is preferably 1,000 to 5,000, and more preferably 1,000 to 3,000. When the polyester polyol (B) contains a plurality of polyester polyols in order to satisfy various physical properties required for the packaging material, the weight-average molecular weight of the polyester polyol (B) can be determined from the weight-average molecular weight of each polyester polyol and the mass ratio thereof.

[0047] [Other polyols] The polyol compound of the present invention may contain other polyols other than the polyester polyol (B) having an acid value of 10 to 50 mgKOH / g, as long as the effects of the present invention are not impaired. Examples of other polyols that may be contained include polyester polyols having an acid value of less than 10 mgKOH / g or more than 50 mgKOH / g, polycarbonate polyols, polycaprolactone polyols, polyether polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, and fluorine-based polyols. As described in the section on polyester polyol (B), some of the hydroxyl groups in the polyol may be reacted with diisocyanate to introduce urethane bonds, or with acid anhydride to introduce carboxyl groups. These other polyols may be used singly or in combination of two or more.

[0048] <Solvent> The reactive adhesive of the present invention can be used as either a solvent-based or solventless type, and can contain a solvent as needed. In this specification, the term "solvent" refers to an organic solvent that has high solubility and can dissolve the polyol compound and polyisocyanate compound of the present invention. 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, toluene, xylol, n-hexane, and cyclohexane. The organic solvent is more preferably one that is inactive to the polyisocyanate compound, and for example, esters such as ethyl acetate; ketones such as methyl ethyl ketone; and aromatic hydrocarbons such as toluene and xylene are preferably used.

[0049] The viscosity of the adhesive of the present invention is preferably 100 to 10,000 mPa·s, more preferably 100 to 5,000 mPa·s, at room temperature to 150° C., and even more preferably 100 to 10,000 mPa·s, more preferably 100 to 5,000 mPa·s, at room temperature to 100° C. When the viscosity is 100 to 5,000 mPa·s at room temperature to 100° C., the adhesive can be used as a solventless adhesive. If 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, but it is generally desirable to include it in the range of 15 to 60 mass % relative to the resin.

[0050] <Preparation of reactive adhesive> The reactive adhesive of the present invention can be obtained by blending at least the above-described polyisocyanate compound and polyol compound, and the blending amount of the polyol compound is preferably 10 to 30 mass %, more preferably 10 to 20 mass %, and even more preferably 10 to 15 mass %, based on the mass of the polyisocyanate compound. The polyol compound and the polyisocyanate compound are preferably mixed in such a ratio that the molar equivalent ratio [NCO / OH] of the total isocyanate groups contained in the polyisocyanate compound to the total hydroxyl groups contained in the polyol compound is 4.0 to 13.0, more preferably 5.0 to 12.0.

[0051] The reactive adhesive of the present invention preferably has an acid value immediately after mixing the polyisocyanate compound and the polyol compound in the range of 1 to 10 mgKOH / g, more preferably 2 to 5 mgKOH / g.

[0052] [Other ingredients] The reactive adhesive of the present invention may contain other components in addition to the polyisocyanate compound and polyol compound in order to satisfy various physical properties required for the adhesive or packaging material. These other components may be blended with the polyisocyanate compound and / or the polyol compound, or may be blended when the polyisocyanate compound and the polyol compound are blended. These other components may be used singly or in combination of two or more.

[0053] (phosphorus oxygen acid or its derivative) The reactive adhesive of the present invention may further contain a phosphorus oxyacid or a derivative thereof to enhance acid resistance. Among the phosphorus oxyacids or derivatives thereof, any phosphorus oxyacid may be used as long as it has at least one free oxyacid. Examples 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. Furthermore, examples of derivatives of phosphorus oxyacids include those partially esterified with alcohols, leaving at least one free oxyacid. Examples of such alcohols include aliphatic alcohols such as methanol, ethanol, ethylene glycol, and glycerin; and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol, and phloroglucinol. The amount of phosphorus oxyacid or a derivative thereof is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and even more preferably 0.1 to 1% by mass, based on the solids content of the reactive adhesive.

[0054] (Leveling agent or defoaming agent) The reactive adhesive of the present invention can further contain a leveling agent or an antifoaming agent to improve the appearance of the laminate. Examples of leveling agents include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, polyetherester-modified hydroxyl group-containing polydimethylsiloxane, acrylic copolymer, methacrylic copolymer, polyether-modified polymethylalkylsiloxane, acrylic acid alkyl ester copolymer, methacrylic acid alkyl ester copolymer, and lecithin. Examples of the antifoaming agent include silicone resin, silicone solution, and copolymers of alkyl vinyl ether, alkyl acrylate, and alkyl methacrylate.

[0055] (Reaction accelerator) The reactive adhesive of the present invention can further contain a reaction accelerator to promote the urethanization reaction. Examples of reaction accelerators include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimaleate; tertiary amines such as 1,8-diazabicyclo(5,4,0)undecene-7 and 1,5-diazabicyclo(4,3,0)nonene-5,6-dibutylamino-1,8-diazabicyclo(5,4,0)undecene-7; and reactive tertiary amines such as triethanolamine.

[0056] The reactive adhesive of the present invention may contain various additives to the extent that the effects of the present invention are not impaired. Examples of additives 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, etc.), rust inhibitors, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, fillers, nucleating agents, and catalysts for adjusting the curing reaction.

[0057] The reactive adhesive of the present invention forms a cured product by bonding two adherends together and then curing the adhesive at a temperature of 20° C. to 60° C. The use of the reactive adhesive is not limited to a specific one, but it is useful as an adhesive for laminating multiple substrates such as films to form a laminate.

[0058] <Laminates and packaging> The laminate of the present invention is formed by laminating a layer of the reactive adhesive of the present invention between a first substrate and a second substrate. Specifically, when the reactive adhesive of the present invention is solvent-based, it can be obtained by applying it to the first substrate using a dry laminator, optionally undergoing a drying process, laminating the second substrate to the coated surface, and curing the adhesive layer by aging. When the reactive adhesive is solventless, it can be obtained using a non-solvent laminator, typically by heating a roll coater to 30°C to 90°C and using an adhesive with a viscosity of about 300 to 3,000 mPa·s at the coating temperature (30°C to 90°C) after blending. The solid content of the reactive adhesive is preferably 0.5 to 6 g / m 2 and more preferably 1 to 3 g / m for the solventless type. 2 , 1 to 5 g / m for solvent-based 2 The range is.

[0059] [First substrate, second substrate] The first substrate is preferably a film substrate commonly used for packaging materials, such as a base film such as PET (polyethylene terephthalate) film, NY (nylon) film, OPP (biaxially oriented polypropylene) film, K-coated film such as polyvinylidene chloride, various vapor-deposited films such as silica-deposited PET and alumina-deposited PET, or aluminum foil. As the second substrate, a film-like substrate commonly used for packaging materials is preferred, and examples thereof include the substrates listed as the first substrate, as well as sealant films such as CPP (non-oriented polypropylene) film, LLDPE (linear low-density polyethylene), LDPE (low-density polyethylene), and HDPE (high-density polyethylene), and aluminum-vapor-deposited or silica-vapor-deposited films of these.

[0060] Examples of the structure of the laminate of the present invention include OPP / CPP, OPP / aluminum-vaporized CPP, nylon / CPP, NY / LLDPE, PET / CPP, PET / aluminum-vaporized CPP, PET / aluminum-vaporized PET / CPP, PET / aluminum-vaporized PET / LLDPE, PET / NY / CPP, alumina-vaporized PET / NY / CPP, PET / aluminum / LLDPE, NY / aluminum / LLDPE, PET / aluminum / CPP, NY / aluminum / CPP, silica-vaporized PET / NY / LLDPE, alumina-vaporized PET / NY / CPP, and PET / NY / PET / NY / aluminum / CPP, and an appropriate structure can be selected depending on the application.

[0061] [Print layer] The laminate of the present invention may further have a printed layer (hereinafter also referred to as an ink layer). The printed layer is a layer on which any desired printed pattern such as letters, numbers, pictures, figures, symbols, designs, etc. is formed for decoration, indication of contents, expiration date, manufacturer, seller, etc., or for the purpose of imparting aesthetic appeal, and includes a solid printed layer. The printed layer can be formed using conventionally known pigments or dyes, and the method for forming the printed layer is not particularly limited. Generally, the printed layer is formed using a printing ink containing a colorant such as a pigment or dye and a binder resin. The binder resin contained in the printing ink is appropriately selected depending on the application and the substrate, and examples thereof include polyurethane resin, polyurethane polyurea resin, vinyl chloride-acrylic acid ester copolymer, vinyl chloride-vinyl acetate copolymer, chlorinated polypropylene resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyamide resin, nitrocellulose resin, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride resin, rosin resin, rosin-modified maleic acid resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, and modified resins thereof. The reactive adhesive of the present invention has excellent adhesive strength, particularly when used with ink containing nitrocellulose resin as a binder component, and therefore exhibits even better adhesive strength in a configuration in which an adhesive layer is placed on a printing layer containing nitrocellulose resin.

[0062] The ink coating method is not particularly limited, and can be applied by methods such as gravure coating, flexo coating, roll coating, bar coating, die coating, curtain coating, spin coating, and inkjet coating. A printed layer can be formed by leaving the ink to stand, or by subjecting it to air blowing, heating, drying under reduced pressure, or ultraviolet irradiation, as necessary. The printed layer preferably has a thickness of 0.1 μm to 10 μm, more preferably 1 μm to 5 μm, and even more preferably 1 μm to 3 μm.

[0063] The laminate of the present invention can be used mainly as a packaging material in the food, detergent, pharmaceutical, cosmetic and toiletry industries, and can also be used as a secondary package for packaging containers made of the packaging material. [Example]

[0064] The present invention will be described in more detail below with reference to examples and comparative examples. In the examples and comparative examples, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0065] <Acid value (AV)> The acid value was measured using the following procedure. First, approximately 1 g of sample (polyester polyol solution) was precisely weighed and placed in a stoppered Erlenmeyer flask, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2 / 1) mixture was added and dissolved. Phenolphthalein test solution was added as an indicator, and the mixture was allowed to stand for 30 seconds. After that, the solution was titrated with 0.1 N alcoholic potassium hydroxide solution until it turned a pale pink color. The acid value was calculated using the following formula. Acid value (mgKOH / g)=(5.611×a×F) / S Where S: sample amount (g) a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml) F: Potency of 0.1N alcoholic potassium hydroxide solution

[0066] <Hydroxyl value (OHV)> The hydroxyl value was measured using the following procedure. First, approximately 1 g of sample (polyester polyol solution) was precisely weighed and placed in a stoppered Erlenmeyer flask, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2 / 1) mixture was added and dissolved. Exactly 5 ml of an acetylating agent (a solution prepared by dissolving 25 g of acetic anhydride in pyridine to a volume of 100 ml) was then added, and the mixture was stirred for approximately 1 hour. Phenolphthalein test solution was added as an indicator, and the mixture was stirred for 30 seconds. The solution was then titrated with 0.1 N alcoholic potassium hydroxide solution until it turned a pale pink color. The hydroxyl value was calculated using the following formula (unit: mgKOH / g). Hydroxyl value (mgKOH / g) =[{(ba)×F×28.05} / S]+D Where S: sample amount (g) a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml) b: Amount of 0.1N alcoholic potassium hydroxide solution consumed in the blank experiment (ml) F: Potency of 0.1N alcoholic potassium hydroxide solution D: Acid value (mgKOH / g)

[0067] <Number average molecular weight (Mn), weight average molecular weight (Mw)> The number average molecular weight and weight average molecular weight were measured using a GPC (gel permeation chromatography) manufactured by Showa Denko K.K., a Shodex GPC LF-604 (manufactured by Shodex) as the column, and a GPC (GPC-104 manufactured by Shodex) equipped with an RI detector, using tetrahydrofuran as the solvent, and the values ​​were converted into standard polystyrene.

[0068] <Residual solvent> The residual solvent amount was measured using a Shimadzu GC-8AFID (Flame Ionization Detector) gas chromatograph (column: 8G26-30 (3.0 m) made of glass, packing material: PEG-1500). First, a laminate cut to a size of 0.2 m2 was finely cut and placed in a 500 mL flask. After sealing with silicone rubber, it was heated to 80°C for 30 minutes. The flask was then removed from the oven, and 1 mL was injected into the gas chromatograph using a gas-tight syringe. The residual solvent amount of the laminated sample was calculated using a calibration curve obtained in advance, and the result was expressed as mg / m 2 It was displayed as.

[0069] <Viscosity measurement> The viscosity was measured by placing the sample in a 225 ml container, adjusting the solution temperature to 25°C, and using a Tokyo Keiki B-type viscometer BL at rotor No. 3 and 12 rpm. The results were expressed in mPa·s.

[0070] <Production of polyurethane polyisocyanate> (Synthesis Example 1) Polyurethane polyisocyanate (A1) 23 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 2,000, 18 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 400, 2 parts of a trifunctional polypropylene glycol, and 32 parts of 4,4'-diphenylmethane diisocyanate were charged into a reaction vessel, and the mixture was heated at 70 to 80°C for 4 to 7 hours while stirring under a nitrogen gas stream to carry out a urethane reaction.After the reaction was completed, the mixture was diluted with ethyl acetate to a non-volatile content of 80%, yielding a solution of polyurethane polyisocyanate (A1), which is a polyether urethane polyisocyanate. The viscosity of the (A1) solution at 25°C was 2,500 mPa·s. The isocyanate group content of (A1) was 4.8%, and the weight average molecular weight was 8,000.

[0071] (Synthesis Example 2) Polyurethane polyisocyanate (A2) 20 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 2,000, 21 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 400, 3 parts of a trifunctional polypropylene glycol, and 23 parts of 4,4'-diphenylmethane diisocyanate were charged into a reaction vessel, and the mixture was heated at 70 to 80°C for 4 to 7 hours while stirring under a nitrogen gas stream to carry out a urethane reaction.After the reaction was completed, the mixture was diluted with ethyl acetate to a non-volatile content of 80%, yielding a solution of polyurethane polyisocyanate (A2), which is a polyether urethane polyisocyanate. The viscosity of the (A2) solution at 25°C was 3,500 mPa·s. The isocyanate group content of (A2) was 4.2%, and the weight average molecular weight was 10,000.

[0072] (Synthesis Example 3) Polyurethane polyisocyanate (A3) A reaction vessel was charged with 30 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 2,000, 6 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 400, 1 part of trifunctional trimethylolpropane, and 20 parts of 4,4'-diphenylmethane diisocyanate, and the mixture was heated at 80-90°C for 3-5 hours with stirring under a nitrogen gas stream to carry out a urethane reaction. After completion of the reaction, the mixture was diluted with ethyl acetate to a non-volatile content of 75%, yielding a solution of polyurethane polyisocyanate (A3), which is a polyether urethane polyisocyanate. The viscosity of the (A3) solution at 25°C was 1,400 mPa·s. The isocyanate group content of (A3) was 5.4%, and the weight-average molecular weight was 9,000.

[0073] (Synthesis Example 4) Polyurethane polyisocyanate (A4) 30 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 2,000, 8 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 400, 5 parts of a trifunctional propylene glycol, and 20 parts of 4,4'-diphenylmethane diisocyanate were charged into a reaction vessel, and the mixture was heated at 80-90°C for 3-5 hours with stirring under a nitrogen gas stream to carry out a urethane reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a non-volatile content of 75%, yielding a solution of polyurethane polyisocyanate (A4), which is a polyether urethane polyisocyanate. The viscosity of the (A4) solution at 25°C was 3,000 mPa·s. The isocyanate group content of (A4) was 3.6%, and the weight average molecular weight was 10,000.

[0074] (Synthesis Example 5) Polyurethane polyisocyanate (A5) 70 parts of adipic acid and 80 parts of diethylene glycol were charged, and an esterification reaction was carried out for 5 hours at 220°C to 230°C. After a predetermined amount of water was distilled off, 0.01 parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixture was heated at 20 to 30 hPa and 220°C to 230°C for 6 hours to distill off a portion of the glycol component and carry out an ester exchange reaction, thereby obtaining a polyester polyol. Next, 510 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 400 and 340 parts of 4,4'-diphenylmethane diisocyanate were charged into a reaction vessel, and the mixture was heated at 80 to 90°C for 3 to 5 hours while stirring under a nitrogen gas flow to carry out a urethane reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a non-volatile content of 75% to obtain a solution of polyurethane polyisocyanate (A5), which is a polyether urethane polyisocyanate. The viscosity of the (A5) solution at 25°C was 2,900 mPa·s. The isocyanate group content of (A5) was 3.8%, and the weight average molecular weight was 10,000.

[0075] (Synthesis Example 6) Polyurethane polyisocyanate (A6) 100 parts of adipic acid and 110 parts of diethylene glycol were charged, and an esterification reaction was carried out for 6 hours at 220°C to 230°C. After a predetermined amount of water was distilled off, 0.01 parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixture was heated at 20 to 30 hPa and 220°C to 230°C for 7 hours to distill off a portion of the glycol component and carry out an ester exchange reaction, thereby obtaining a polyester polyol. Next, 480 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 400 and 360 parts of 4,4'-diphenylmethane diisocyanate were charged into a reaction vessel, and the mixture was heated at 80 to 90°C for 3 to 5 hours while stirring under a nitrogen gas flow to carry out a urethane reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a non-volatile content of 75% to obtain a solution of polyurethane polyisocyanate (A6), which is a polyether urethane polyisocyanate. The viscosity of the (A6) solution at 25°C was 3,400 mPa·s. The isocyanate group content of (A6) was 3.5%, and the weight average molecular weight was 15,000.

[0076] (Synthesis Example 7) Polyurethane polyisocyanate (A7) 30 parts of isophthalic acid, 30 parts of adipic acid, 15 parts of ethylene glycol, and 25 parts of 1,4-butanediol were charged and an esterification reaction was carried out for 6 hours at 200 to 230°C. After a predetermined amount of water was distilled off, 0.01 parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixture was heated at 20 to 30 hPa and 230 to 250°C for 7 hours to distill off a portion of the glycol component and carry out an ester exchange reaction, thereby obtaining a polyester polyol. Next, 400 parts of a bifunctional polypropylene glycol having a number average molecular weight of approximately 400 and 250 parts of 4,4'-diphenylmethane diisocyanate were charged into a reaction vessel, and the mixture was heated at 80 to 90°C for 3 to 5 hours while stirring under a nitrogen gas flow to carry out a urethane reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a non-volatile content of 75% to obtain a solution of polyurethane polyisocyanate (A7), which is a polyether urethane polyisocyanate. The viscosity of the (A7) solution at 25°C was 4,800 mPa·s. The isocyanate group content of (A7) was 3.2%, and the weight-average molecular weight was 20,000.

[0077] <Production of polyester polyol> (Synthesis Example 8) Polyester polyol (B1) 325.8 parts of isophthalic acid, 286.5 parts of adipic acid, 158.2 parts of ethylene glycol, and 229.6 parts of 1,4-butanediol were charged and subjected to an esterification reaction at 200-230°C for 6 hours. After distilling off a predetermined amount of water, 0.01 parts of tetraisobutyl titanate was added, and the pressure was gradually reduced. The mixture was heated at 20-30 hPa and 230-250°C for 6 hours to distill off a portion of the glycol component and induce a transesterification reaction, yielding a polyester polyol. 30 parts of trimellitic anhydride were added to the total amount of this polyester polyol, and the reaction was carried out at 150°C for 2 hours. After the reaction was completed, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of acid-modified polyester polyol (B1) with a weight average molecular weight of 2,000 and an acid value of 20 mgKOH / g.

[0078] (Synthesis Example 9) Polyester polyol (B2) 325.8 parts of isophthalic acid, 286.5 parts of adipic acid, 158.2 parts of ethylene glycol, and 229.6 parts of 1,4-butanediol were charged and subjected to an esterification reaction at 200-230°C for 6 hours. After distilling off a predetermined amount of water, 0.01 parts of tetraisobutyl titanate was added, and the pressure was gradually reduced. The mixture was heated at 20-30 hPa and 230-250°C for 6 hours to distill off a portion of the glycol component and carry out an ester exchange reaction, yielding a polyester polyol. 11 parts of trimellitic anhydride were added to the total amount of this polyester polyol, and the reaction was carried out at 150°C for 2 hours. After the reaction was completed, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of acid-modified polyester polyol (B2) with a weight average molecular weight of 2,100 and an acid value of 10 mgKOH / g.

[0079] (Synthesis Example 10) Polyester polyol (B3) 325.8 parts of isophthalic acid, 286.5 parts of adipic acid, 158.2 parts of ethylene glycol, and 229.6 parts of 1,4-butanediol were charged and subjected to an esterification reaction at 200-230°C for 6 hours. After distilling off a predetermined amount of water, 0.01 parts of tetraisobutyl titanate was added, and the pressure was gradually reduced. The mixture was heated at 20-30 hPa and 230-250°C for 7 hours to distill off a portion of the glycol component and induce a transesterification reaction, yielding a polyester polyol. 70 parts of trimellitic anhydride were added to the total amount of this polyester polyol, and the reaction was carried out at 150°C for 2 hours. After the reaction was completed, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of acid-modified polyester polyol (B3) with a weight average molecular weight of 3,500 and an acid value of 32 mgKOH / g.

[0080] (Synthesis Example 11) Polyester polyol (B4) 330.1 parts of isophthalic acid, 300.5 parts of adipic acid, 258.2 parts of propylene glycol, and 110.2 parts of trimethylolpropane were charged and an esterification reaction was carried out at 200-230°C for 3 hours. After a predetermined amount of water was distilled off, 0.01 parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixture was heated at 20-30 hPa and 220-230°C for 3 hours to distill off a portion of the glycol component and carry out an ester exchange reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of polyester polyol (B4) with a weight average molecular weight of 2,000 and an acid value of 20 mgKOH / g.

[0081] (Synthesis Example 12) Polyester polyol (B5) 330.1 parts of isophthalic acid, 300.5 parts of adipic acid, 258.2 parts of propylene glycol, and 110.2 parts of trimethylolpropane were charged and subjected to an esterification reaction at 200-230°C for 4 hours. After a predetermined amount of water was distilled off, 0.01 parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixture was heated at 20-30 hPa and 220-230°C for 4 hours to distill off a portion of the glycol component and perform an ester exchange reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of polyester polyol (B5) with a weight average molecular weight of 2,000 and an acid value of 18 mgKOH / g.

[0082] (Synthesis Example 13) Polyester polyol (B6) 325.8 parts of isophthalic acid, 286.5 parts of adipic acid, 158.2 parts of ethylene glycol, and 229.6 parts of 1,4-butanediol were charged and an esterification reaction was carried out at 200-230°C for 6 hours. After a predetermined amount of water was distilled off, 0.01 parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixture was heated at 20-30 hPa and 230-250°C for 6 hours to distill off a portion of the glycol component and carry out an ester exchange reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of polyester polyol (B6) with a weight average molecular weight of 2,000 and an acid value of 3 mgKOH / g.

[0083] (Synthesis Example 14) Polyester polyol (B7) 340.0 parts of isophthalic acid, 115.5 parts of sebacic acid, 41.2 parts of adipic acid, 130.2 parts of ethylene glycol, 165.5 parts of 1,6-hexanol, and 186.4 parts of neopentyl glycol were charged and subjected to an esterification reaction at 200-230°C for 6 hours. After a predetermined amount of water was distilled off, 0.01 parts of tetraisobutyl titanate was added, the pressure was gradually reduced, and the mixture was heated at 20-30 hPa and 230-250°C for 8 hours to distill off a portion of the glycol component and perform a transesterification reaction. After the reaction was completed, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of polyester polyol (B7) with a weight average molecular weight of 2,300 and an acid value of 2 mgKOH / g.

[0084] <Production of Resin Having Acid Value> (Synthesis Example 15) (Meth)acrylic acid ester-maleic anhydride copolymer (C-1) A reaction vessel equipped with a stirrer, temperature control system, reflux condenser, dropping tank, and nitrogen gas inlet tube was charged with 200 parts of toluene, and the temperature was raised to 110 ° C. while stirring and introducing nitrogen gas. Next, dropping tank 1 was charged with 80 parts of methyl methacrylate, 50 parts of butyl acrylate, 100 parts of maleic anhydride, and 50 parts of toluene, and dropping tank 2 was charged with a solution of 9 parts of benzoyl peroxide in 50 parts of toluene. Each was simultaneously added dropwise over 2 hours with stirring while maintaining the temperature inside the reaction vessel at 110 ° C. After the reaction was completed, the mixture was cooled to room temperature, and the polymer was precipitated with a large amount of methanol, filtered, and dried at 120 ° C. for 6 hours to obtain a (meth)acrylic acid ester-maleic anhydride copolymer (C-1) with a weight average molecular weight of 10,000 and an acid value of 460 mg KOH / g.

[0085] (Synthesis Example 16) Copolymer of aromatic vinyl and maleic anhydride (C-2) A reaction vessel equipped with a stirrer, a temperature control system, a reflux condenser, a dropping tank, and a nitrogen gas inlet tube was charged with 200 parts of toluene, and the temperature was raised to 110°C with stirring while introducing nitrogen gas. Next, 150 parts of styrene, 150 parts of maleic anhydride, and 50 parts of toluene were charged into dropping tank 1, and a solution of 9 parts of benzoyl peroxide in 50 parts of toluene was charged into dropping tank 2. Each was simultaneously added dropwise over 2 hours with stirring while maintaining the temperature inside the reaction vessel at 110°C. After the reaction was completed, the mixture was cooled to room temperature, and the polymer was precipitated with a large amount of methanol, filtered, and dried at 120°C for 6 hours to obtain a styrene-maleic anhydride copolymer (C-2) with a weight average molecular weight of 2,800 and an acid value of 400.

[0086] <Production of polyether urethane polyol> (Synthesis Example 17) Polyurethane polyol (D1) A reaction vessel was charged with 80 parts of a difunctional polypropylene glycol with a number-average molecular weight of approximately 2,000, 360 parts of a difunctional polypropylene glycol with a number-average molecular weight of approximately 400, 8 parts of trifunctional trimethylolpropane, and 20 parts of toluene diisocyanate. The urethane reaction was carried out by heating at 80-90°C for 3-5 hours while stirring under a nitrogen gas stream. After the reaction was complete, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of polyurethane polyol (D1), a polyether urethane polyol. The viscosity of the (D1) solution at 25°C was 5,400 mPa·s, and the weight-average molecular weight of (D1) was 10,000.

[0087] (Synthesis Example 16) Polyurethane polyol (D2) A reaction vessel was charged with 160 parts of a difunctional polypropylene glycol with a number-average molecular weight of approximately 2,000, 240 parts of a difunctional polypropylene glycol with a number-average molecular weight of approximately 400, 4 parts of trifunctional trimethylolpropane, and 23 parts of toluene diisocyanate. The urethane reaction was carried out by heating at 80-90°C for 3-5 hours while stirring under a nitrogen gas stream. After the reaction was complete, the mixture was diluted with ethyl acetate to a nonvolatile content of 75% to obtain a solution of polyurethane polyol (D2), a polyether urethane polyol. The viscosity of the (D2) solution at 25°C was 6,800 mPa·s, and the weight-average molecular weight of (D2) was 15,000.

[0088] <Production of reactive adhesives> The polyurethane polyisocyanate solution, polyester polyol solution, and other components were mixed and stirred in the formulations shown in Tables 1 and 2 to produce reactive adhesives.

[0089] <Evaluation of reactive adhesives> The resulting adhesive was used to determine the peak area ratio V of the cured film.

[0090] [Area ratio V of cured product measured by ATR-FTIR] The resulting reactive adhesive was applied to aluminum foil (Toyo Aluminum, thickness 7 μm) using a laminator at a coating speed of 50 m / min. The solvent was evaporated in a drying oven (70°C-80°C-80°C triple oven, furnace length 2.0 m), and then the film was laminated to the untreated side of a CPP film (Toray ZK207, thickness 70 μm). The solids application amount of the adhesive was 2.5 g / m. 2 It was decided. The CPP film was peeled off from the resulting laminate to obtain a test piece comprising a cured product of the reactive adhesive on an aluminum substrate. The absorbance of the resulting test piece was measured by the ATR-FTIR method using an ATR-FTIR ATR-FTIR instrument manufactured by BRUKER. The measurement was performed at a position 1 to 2 μm from the surface of the cured product toward the substrate, in the wavenumber range of 400 to 4000 cm. -1 , resolution 4cm -1 The scan was performed 16 times. From the obtained infrared absorption spectrum, the peak area tool was used to find the peak at wavenumber 1075 cm -1 ~1150cm -1 The peak area v1 of the absorbance due to the ether bond, which has an absorption maximum in the region of 1715 cm -1 ~1750cm -1 The peak area v2 of absorbance derived from ester bonds having an absorption maximum in the region was determined. The baseline was taken as the line connecting the bases at both ends of the absorption curve where a peak exists or the valley between two absorption curves. Next, the peak area ratio V was calculated using the above formula (1). V was the average value of six arbitrary points calculated from the same sample.

[0091] <Laminate production and evaluation> The adhesive was used to prepare the following laminates, which were then evaluated. The results are shown in Tables 1 and 2. However, Examples 9 to 12 and Example 14 in Table 1 are reference examples.

[0092] [OPP / printing layer / adhesive layer / VMCPP composition] (Laminate (1-1)) Nitrocellulose / urethane ink, coating speed 200m / min Printing inks (Toyo Ink Co., Ltd., RV-R 16 Red and 63 White, both nitrocellulose / urethane inks) were diluted with a mixed solvent (ethyl acetate / propyl acetate / isopropanol = 50 / 20 / 30 (mass ratio)) to a viscosity of 20 seconds (25°C, Zahn cup No. 3). Each diluted printing ink was printed on corona-treated OPP film (Toyobo P-2161, 20 μm thick) in the order of red, white, and red-and-white overlapping using a flexographic proofing 8-color press equipped with a solid plate. The printing speed was 50 m / min, and drying was performed at 50°C in each unit to obtain an OPP / printed layer laminate. The thickness of the printed layer was 1 μm for each color and 2 μm for the overlapping layers. The resulting reactive adhesive was applied to the printed layer of the laminate at a coating speed of 200 m / min using a laminator. The solvent was evaporated in a drying oven (70°C-80°C-80°C triple oven, furnace length 2.0 m). The adhesive-coated surface was then laminated with a VMCPP film (2703, manufactured by Toray Film Processing Co., Ltd., 25 μm thick, aluminum-vapor-deposited non-oriented polypropylene) to obtain laminate (1-1). The solids coating amount of the adhesive was 2.5 g / m. 2 It was decided.

[0093] (Laminate (1-2)) Urethane ink, coating speed 200 m / min Printing inks (Toyo Ink Co., Ltd., Rio Alpha R39 indigo and R631 white, both urethane inks) were diluted with a mixed solvent to a viscosity of 16 seconds (25°C, Zahn cup No. 3). Each diluted printing ink was printed onto a corona-treated OPP film (Toyobo P-2161, 20 μm thick) using a gravure proofing two-color press equipped with a solid printing plate, in the order of blue, white, and indigo-white overlapping. The printing speed was 50 m / min, and drying was performed at 50°C in each unit, resulting in an OPP / printed layer laminate. The thickness of the printed layer was 1 μm for each color and 2 μm for the overlapping layers. The resulting reactive adhesive was applied to the printed layer of the laminate at a coating speed of 200 m / min using a laminator. The solvent was evaporated in a drying oven (70°C-80°C-80°C triple oven, furnace length 2.0 m). The adhesive-coated surface was then laminated with a VMCPP (2703, manufactured by Toray Film Processing Co., Ltd., 25 μm thick, aluminum-vapor-deposited non-oriented polypropylene) film to obtain laminate (1-2). The solids coating amount of the adhesive was 2.5 g / m. 2 It was decided.

[0094] (Laminate (1-3)) Nitrocellulose / urethane ink, coating speed 230 m / min A laminate (1-3) was obtained in the same manner as for the laminate (1-1), except that the coating speed of the adhesive was changed from 200 m / min to 230 m / min.

[0095] [PET / printed layer / adhesive layer / aluminum / adhesive layer / LLDPE] (Laminate (2-1)) Nitrocellulose / urethane ink, coating speed 150m / min Printing inks (RV-R 16 Red and 63 White, manufactured by Toyo Ink Co., Ltd., both nitrocellulose / urethane inks) were diluted with a mixed solvent to a viscosity of 20 seconds (25°C, Zahn cup No. 3). Each diluted printing ink was printed on corona-treated PET film (Toyobo E5102, 12 μm thick) in the order of red, white, and red-and-white overlapping using a flexographic proofing 8-color press equipped with a solid plate. The printing speed was 50 m / min, and drying was carried out at 50°C in each unit, resulting in a PET / printed layer laminate. The thickness of the printed layer was 1 μm for each color and 2 μm for the overlapping layers. The resulting reactive adhesive was applied to the printed layer of the above laminate using a laminator at a coating speed of 150 m / min, and the solvent was evaporated using a drying oven (a triple oven at 70°C-80°C-80°C, furnace length 2.0 m).The adhesive-coated surface was then bonded to aluminum foil (manufactured by Toyo Aluminum, thickness 7 μm) to obtain a laminate of PET / printed layer / adhesive layer / aluminum. Next, a reactive adhesive was similarly applied to the aluminum foil of the laminate, and after the solvent was evaporated, the adhesive-coated surface was bonded to an LLDPE film (Mitsui Chemicals Tocello TUX-FCD, thickness 100 μm) to obtain a laminate (2-1). The solid content of the adhesive was 2.5 g / m 2 It was decided.

[0096] (Laminate (2-2)) Urethane ink, coating speed 150 m / min Printing inks (Toyo Ink Co., Ltd., Rio Alpha R39 indigo and R631 white, both urethane inks) were diluted with a mixed solvent to a viscosity of 16 seconds (25°C, Zahn cup No. 3). Each diluted printing ink was printed onto a corona-treated PET film (Toyobo E5102, 12 μm thick) in the order of blue, white, and indigo-white overlapping, using a gravure proofing two-color press equipped with a solid printing plate. The printing speed was 50 m / min, and drying was carried out at 50°C in each unit, yielding a PET / printed layer laminate. The thickness of the printed layer was 1 μm for each color and 2 μm for the overlapping layers. The resulting reactive adhesive was applied to the printed layer of the above laminate using a laminator at a coating speed of 150 m / min, and the solvent was evaporated using a drying oven (a triple oven at 70°C-80°C-80°C, furnace length 2.0 m).The adhesive-coated surface was then bonded to aluminum foil (manufactured by Toyo Aluminum, thickness 7 μm) to obtain a laminate of PET / printed layer / adhesive layer / aluminum. Next, a reactive adhesive was similarly applied to the aluminum foil of the laminate, and after the solvent was evaporated, the adhesive-coated surface was bonded to an LLDPE film (Mitsui Chemicals Tocello TUX-FCD, thickness 100 μm) to obtain a laminate (2-2). The solid content of the adhesive was 2.5 g / m 2 It was decided.

[0097] [Adhesion strength between OPP / VMCPP (initial)] The laminates (1-1) and (1-2) were stored at 40°C for 24 hours to cure the adhesive. Test pieces measuring 15 mm x 300 mm were cut from the cured laminates, and the adhesive strength (N / 15 mm) between the OPP and VMCPP was measured using a tensile tester at a temperature of 20°C and a relative humidity of 65% using a T-peel method at a peel rate of 30 cm / min. The average value of five test pieces was calculated and evaluated according to the following criteria. A: Adhesion strength is 1.5N / 15mm or more (good) B: Adhesive strength is 1.0N / 15mm or more and less than 1.5N / 15mm (usable) C: Adhesive strength is less than 1.0N / 15mm (unusable)

[0098] [Adhesion strength between OPP / VMCPP (over time)] The laminates (1-1) and (1-2) were stored at 40°C for 24 hours to cure the adhesive, and then further stored in an environment of 40°C and 70% humidity for one month. Using the laminates after storage, the adhesive strength was measured in the same manner as in [Adhesion strength between OPP / VMCPP (initial)], and the average value of five test pieces was calculated and evaluated according to the following criteria. A: Adhesion strength is 1.5N / 15mm or more (good) B: Adhesive strength is 1.0N / 15mm or more and less than 1.5N / 15mm (usable) C: Adhesive strength is less than 1.0N / 15mm (unusable)

[0099] [Adhesion strength between PET / AL / LLDPE (initial)] The laminates (2-1) and (2-2) were stored at 40°C for 48 hours to cure the adhesive. Test pieces measuring 15 mm x 300 mm were cut from the cured laminates, and the adhesive strength (N / 15 mm) between the PET and Al was measured using a tensile tester at a temperature of 20°C and a relative humidity of 65% using a T-peel method at a peel rate of 30 cm / min. The average value of five test pieces was calculated and evaluated according to the following criteria. A: Adhesion strength is 3.0N / 15mm or more (good) B: Adhesive strength is 1.5N / 15mm or more and less than 3.0N / 15mm (usable) C: Adhesive strength is less than 1.5N / 15mm (unusable)

[0100] [Adhesion strength between PET / AL / LLDPE (over time)] The laminates (2-1) and (2-2) were stored at 40°C for 24 hours to cure the adhesive, and then further stored in an environment of 40°C and 70% humidity for one month. After storage, the laminates were used to measure the adhesive strength in the same manner as in [Adhesion strength between PET / AL / LLDPE (initial)], and the average value of five test pieces was calculated and evaluated according to the following criteria. A: Adhesion strength is 3.0N / 15mm or more (good) B: Adhesive strength is 1.5N / 15mm or more and less than 3.0N / 15mm (usable) C: Adhesive strength is less than 1.5N / 15mm (unusable)

[0101] [Residual solvent] The amounts of residual solvent in the laminates (1-1) and (1-2) were measured and evaluated according to the following criteria. A: The amount of residual solvent is less than 2.0 mg / m² (good) B: Residual solvent amount is 2.0 mg / m² or more and less than 3.0 mg / m² (usable) C: Residual solvent amount is 3.0 mg / m2 or more (unusable)

[0102] [High-speed coating ability] The appearance of each laminate was visually inspected for two laminates (1-1) and (1-3) with different coating speeds, and those with no appearance defects such as spots were rated as A, those with only slight spots were rated as B, and those with spots were rated as C. The results for the three laminates were combined and evaluated according to the following criteria. A: A rating (good) at a coating speed of 230 m / min. B: Grade B or C at a coating speed of 230 m / min, but grade A (usable) at 200 m / min C: Grade B or C at a coating speed of 200 m / min (unusable)

[0103] [Table 1]

[0104] [Table 2]

[0105] According to Tables 1 and 2, the adhesives of the present invention shown in the examples exhibited excellent adhesive strength even without the use of a silane coupling agent, particularly when used with inks containing nitrocellulose resin (nitrocellulose) as a binder. Furthermore, high-speed coating at 200 m / min or higher resulted in excellent laminate appearance and reduced residual solvent. In particular, excellent adhesive performance was exhibited when the peak area ratio V was in the range of 0.92 to 1.0. Furthermore, excellent adhesive stability and reduced residual solvent were observed when the acid value after blending was in the range of 2 to 5. On the other hand, the adhesive of the comparative example did not satisfy all of the requirements for adhesive strength, residual solvent, and high-speed coating property when using ink containing nitrocellulose resin.

Claims

1. A reactive adhesive comprising a polyisocyanate compound and a polyol compound, the polyisocyanate compound contains a polyurethane polyisocyanate (A) which is a reaction product of an aromatic polyisocyanate (a1) and a polyol (a2) having an ether bond, The polyurethane polyisocyanate (A) has a weight average molecular weight in the range of 5,000 to 20,000, the polyol compound comprises a polyester polyol (B) having an acid value in the range of 10 to 50 mgKOH / g, a peak area ratio V of a cured product of the reactive adhesive as measured by an ATR-FTIR method is 0.90≦V≦1.10; the reactive adhesive contains only the polyurethane polyisocyanate (A) as a compound having an ether bond, A reactive adhesive in which the compound having an ester bond contained in the reactive adhesive is the polyester polyol (B) only. The peak area ratio V is determined by the following steps <1> to <3>. <1> On an aluminum substrate, a solid content coating amount of 2.5 g / m ２ After the solvent is evaporated, the film is laminated to the untreated surface of a non-oriented polypropylene film and cured at 40° C. and 60% RH for 3 days. <2> The unstretched polypropylene film is peeled off, and a portion of the exposed cured reactive adhesive 1 to 2 μm from the surface toward the substrate is measured by ATR-FTIR at a wave number of 1020 cm －１ ~1150cm －１ The absorbance peak area v1 at the wavenumber 1715 cm －１ ~1750cm －１ The absorbance peak area v2 at <3> The peak area ratio V is calculated from v1 and v2 using the following formula (1). Peak area ratio V = peak area v1 / peak area v2 (1)

2. The reactive adhesive according to claim 1 , wherein the aromatic polyisocyanate (a1) is diphenylmethane diisocyanate or a derivative thereof.

3. The reactive adhesive according to claim 1 or 2, wherein the polyol (a2) comprises a polyalkylene glycol.

4. The reactive adhesive according to any one of claims 1 to 3, wherein the polyester polyol (B) has a weight average molecular weight in the range of 1,000 to 3,000.

5. A laminate comprising an adhesive layer, which is a cured product of the reactive adhesive according to any one of claims 1 to 4, between a first substrate and a second substrate.

6. A laminate comprising an adhesive layer, which is a cured product of a reactive adhesive, between a first substrate and a second substrate, the reactive adhesive contains a polyisocyanate compound and a polyol compound; the polyisocyanate compound contains a polyurethane polyisocyanate (A) which is a reaction product of an aromatic polyisocyanate (a1) and a polyol (a2) having an ether bond, The polyurethane polyisocyanate (A) has a weight average molecular weight in the range of 5,000 to 20,000, the polyol compound comprises a polyester polyol (B) having an acid value in the range of 10 to 50 mgKOH / g, the peak area ratio V of the adhesive layer measured by ATR-FTIR method is 0.90≦V≦1.10; the reactive adhesive contains only the polyurethane polyisocyanate (A) as a compound having an ether bond, A laminate, wherein the reactive adhesive contains only the polyester polyol (B) as a compound having an ester bond. The peak area ratio V is determined by the following steps <4> and <5>. <4> The first substrate and the second substrate are peeled off, and a portion of the exposed cured reactive adhesive 1 to 2 μm from the surface toward the substrate is measured by ATR-FTIR at a wave number of 1020 cm －１ ~1150cm －１ The absorbance peak area v1 at the wavenumber 1715 cm －１ ~1750cm －１ The absorbance peak area v2 at <5> The peak area ratio V is calculated from v1 and v2 using the following formula (1). Peak area ratio V = peak area v1 / peak area v2 (1)

7. A package using the laminate according to claim 5 or 6.

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