JP6904239B2 - Adhesive composition and laminate - Google Patents

Description

The present invention relates to a laminate having an ink layer and an adhesive layer, and more particularly to a laminate useful as a packaging material for foods, medical products, cosmetics, and the like.

The bonding between various plastic films and the bonding between a plastic film and a metal vapor-deposited film or a metal foil have conventionally been performed by a dry laminating method using a hydroxyl group / isocyanate-based solvent-based adhesive composition. However, since the dry laminating method uses an adhesive composition containing an organic solvent, special equipment for suppressing / preventing environmental pollution and fire is required.

In recent years, there has been an increasing demand for solvent-free adhesive compositions due to the demand for simple equipment, and research on solvent-free adhesives has been actively conducted.
For example, Patent Document 1 discloses a solvent-free type adhesive composition for laminating containing a polyol component (1) and a polyisocyanate component (2) composed of two types of polyisocyanate compounds.
Further, Patent Document 2 describes that the branch point concentration is in a specific range and contains a polyol component (1) and a polyisocyanate component (2) in which a trifunctional polyisocyanate compound is essential, and the number of molar hydroxyl groups: isocyanate group. A solvent-free laminate adhesive composition having a number of moles = 1: 1 to 1: 3 is disclosed.
Patent Document 3 discloses a solvent-free adhesive composition containing a polyol component (A) and an isocyanate component (B) that requires isophorone diisocyanate.
Patent Document 4 discloses a solvent-free adhesive composition containing a polyol component (A), a polyisocyanate compound (B), and a powder (C) having a specific particle size.
Further, Patent Document 5 contains a polyisocyanate component (A) and a polyol component (B), and the polyisocyanate component (A) is 2,4'-diphenylmethane diisocyanate (a1) and 4,4'-diphenylmethane diisocyanate ( It is a reactive product obtained by reacting a2) with a polyol requiring a polyether polyol (a3) under a condition of excess isocyanate group, and the polyol component (B) has a number average molecular weight of 500 or more and 3000 or less. A polyester diol (b1) is essential, and an adhesive composition containing at least one of a diol (b2) and a triol (b3) having a number average molecular weight of 50 or more and less than 500 is disclosed.
Further, claim 2 of Patent Document 6 includes an exterior polyethylene terephthalate film layer (F1), a dry film layer (P) for printing ink, a dry film layer (C) for a coating resin, and a solvent-free adhesive layer (A). ), The metal vapor-deposited layer or the metal foil (M), and the interior plastic film layer (F2) are described in this order.
Further, Patent Document 7 discloses a two-component curable solvent-free adhesive composition containing a specific amount of a crystalline polyol component in the total amount of the polyol component (A) and the polyisocyanate component (B). ..
Patent Document 8 describes an adhesion containing a specific polyisocyanate component (A) containing a urethane prepolymer made from a polyether polyol and crude MDI, and a specific polyol component (B) containing a polyester diol as an essential component. The agent composition is described.

Japanese Unexamined Patent Publication No. 8-60131 Japanese Unexamined Patent Publication No. 2003-96428 Japanese Unexamined Patent Publication No. 2006-57089 Japanese Unexamined Patent Publication No. 2011-162579 Japanese Unexamined Patent Publication No. 2014-159548 Japanese Unexamined Patent Publication No. 2010-280122 Japanese Unexamined Patent Publication No. 2002-249745 Patent No. 5812219

The laminate as a packaging material has a printing ink layer, an adhesive layer, and a base material on one surface (hereinafter, also referred to as a back surface and a back side) of a transparent base material. The printing ink layer is seen from the opposite side (hereinafter, also referred to as the front side and the front side) of the transparent base material. The printing ink layer may be provided so as to cover the entire surface, or may be partially provided. The printing ink layer may be a single layer or a plurality of layers may be stacked. The portion provided with the printing ink layer is also referred to as an ink portion, and the portion not provided with the printing ink layer is also referred to as a plain portion.

The solvent-free adhesive composition has no drying process and no solvent discharge, is energy-saving and has good running cost, and is a laminate after plastic films are bonded together, or a plastic film and a metal foil or metal vapor deposition. It has many merits such as no concern that the solvent remains in the laminate after the layers are bonded together. However, when a solvent-free adhesive composition and a base material having a high gas barrier property (hereinafter, also referred to as a barrier base material) having a metal vapor deposition layer provided on the film are used to form a laminate as a packaging material. There is a problem that the appearance of the ink portion is poorly formed like a yuzu skin.

Patent Documents 1 to 4 describe that a relatively mild reaction is used as the polyisocyanate component, specifically, an alicyclic polyisocyanate component or an aliphatic polyisocyanate component is used. However, the polyisocyanate component, which has a relatively mild reaction, has a problem that the aging step requires 2 to 5 days at 40 to 50 ° C. Further, Patent Documents 1 to 4 do not describe improvement of appearance defects in the ink portion. The aging step means "a step of advancing the curing of the adhesive layer".

Further, Patent Document 5 discloses an adhesive composition which controls the reactivity with water and has good adhesive performance and good pot life even at high humidity. However, Patent Document 5 also does not mention the improvement of the appearance defect in the ink portion.

In [0013] and [0014] of Patent Document 6, when a dry film layer (P) of printing ink is provided between the outer polyethylene terephthalate film layer (F1) and the dry film layer (C) of the coating resin. It is disclosed that the coating resin constituting the dry film layer (C) of the coating resin uses a binder for printing ink to improve the appearance of the ink portion. However, the processing speed specifically shown in the examples, that is, the coating speed of the adhesive is as low as only 10 m / min. Since the solvent-free adhesive composition is solvent-free, the coated surface becomes rough when the coating speed is increased, so that it has not been possible to improve the coating speed and the appearance at the same time. From the viewpoint of improving productivity, it is desirable that the solvent-free adhesive composition also has a laminate having a good appearance of the ink portion at the same level as the solvent-based adhesive composition, for example, at a coating speed of about 200 m / min. It has come to be.

On the other hand, Patent Document 7 discloses that by using a solvent-free adhesive composition containing a specific amount of crystalline polyester, the appearance of the ink portion is to be improved even at a coating speed of 200 m / min. ing. However, since crystalline polyester is used, poor appearance could not be improved by low temperature aging at 40 ° C. or lower.

Further, Patent Document 8 describes that a laminate having an excellent appearance can be obtained by coating at a speed of 200 m / min or more and aging at a low temperature in a short time, but improvement in the appearance of the printed portion is desired. It was rare.

An object of the present invention is to use a base material having excellent gas barrier properties, for example, a base material having an oxygen permeability of 100 CC (m ² , 24 hr, 1 atm, 25 ° C.) or less, at a high speed, for example, a coating speed of 200 m / min. An adhesive composition is applied to provide a laminate having a good appearance of a printed portion by aging at a low temperature of 40 ° C. or lower for a short time.

The present invention has been made in view of the above problems, and relates to an adhesive composition and a laminate.
That is, the adhesive composition of the present invention is an adhesive composition containing a polyisocyanate component (A) and a polyol component (B), and satisfies all of the following conditions (1) to (7).
(1) An ester (C) of a compound having a carboxyl group and a monohydric alcohol with respect to a total of 100 parts by mass of the polyisocyanate component (A) and the polyol component (B), which is liquid at 25 ° C. Is further contained in an amount of 0.1 to 20 parts by mass.
(2) The polyisocyanate component (A) contains a urethane prepolymer (a) having an isocyanate group and 4,4'-diphenylmethane diisocyanate.
(3) The polyisocyanate component (A) is a trimer of a bifunctional isocyanate monomer, a bullet body in which water is added to a bifunctional isocyanate monomer, and a bifunctional or higher polyhydric alcohol in the bifunctional isocyanate monomer. It further comprises a modified version of at least one bifunctional isocyanate monomer selected from the group consisting of added adducts.
(4) The polyisocyanate component (A) may further contain at least one isocyanate component selected from the group consisting of 2,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, and xylene diisocyanate. ..
(5) The urethane prepolymer (a) having an isocyanate group is a reaction product of 4,4'-diphenylmethane diisocyanate and a polyol requiring a polyether polyol.
(6) In 100% by mass of the polyol component (B), 70 to 100% by mass of a polyether polyurethane polyol having a number average molecular weight of 200 or more and 3000 or less is contained.
(7) The total amount of 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, and xylene diisocyanate contained in 100% by mass of the adhesive composition is It is 10 to 34% by mass.

In the adhesive composition of the present invention, the monohydric alcohol preferably has 1 to 20 carbon atoms.

Further, in the adhesive composition of the present invention, it is preferable that the ester (C) liquid at 25 ° C. is a diester of a compound having two carboxyl groups and a monohydric alcohol.

Further, the present invention is a laminate having a transparent base material 1, an ink layer, an adhesive layer, and ^{a base material 2 having an oxygen permeability of 100 CC (m 2} , 24 hr, 1 atm, 25 ° C.) or less in this order. The present invention relates to a laminate in which the adhesive layer is a cured product of the adhesive composition of the present invention.

According to the present invention, when a substrate having excellent gas barrier properties having an oxygen permeability of 100 CC (m ² , 24 hr, 1 atm, 25 ° C.) or less is used, the adhesive composition is applied at a high speed, for example, a coating speed of 200 m / min. Even when aged at a low temperature of 40 ° C. or lower for a short time, an adhesive performance of 0.6 N or more is exhibited in a width of 15 mm, and a laminated body having a good appearance of a printed portion can be provided.

The adhesive composition of the present invention contains a polyisocyanate component (A), a polyol component (B), and an ester (C) of a monohydric alcohol liquid at 25 ° C.
The polyisocyanate component (A) contained in the adhesive composition in the present invention will be described.
Hereinafter, 4,4'-diphenylmethane diisocyanate is used as 4,4'-MDI,
2,4'-Diphenylmethane diisocyanate with 2,4'-MDI,
TDI for tolylene diisocyanate, XDI for xylylene diisocyanate,
Hexamethylene diisocyanate is HDI, isophorone diisocyanate is IPDI
It may be abbreviated as.

The polyisocyanate component (A) contains a urethane prepolymer (a) having an isocyanate group and 4,4'-diphenylmethane diisocyanate.
Further, the polyisocyanate component (A) is a trimer of a bifunctional isocyanate monomer, a bullet body in which water is added to the bifunctional isocyanate monomer, and a bifunctional or higher polyhydric alcohol added to the bifunctional isocyanate monomer. It further contains a modified version of at least one bifunctional isocyanate monomer selected from the group consisting of the adducts.
The polyisocyanate component (A) may contain at least one isocyanate component selected from the group consisting of 2,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, and xylene diisocyanate.
The urethane prepolymer (a) can be obtained by reacting an isocyanate component and a polyol under conditions of excess isocyanate groups.
It is a reaction product of an isocyanate component that requires 4,4'-MDI and a polyol that requires a polyether polyol. As the isocyanate component, 2,4'-MDI, TDI and the like can be used in addition to 4,4'-MDI.

That is, examples of the polyisocyanate component (A) used in the present invention include (A1) to (A3).
(A1) Urethane prepolymer (a), which is a reaction product of 4,4'-MDI and a polyol requiring a polyether polyol, and
4,4'-MDI and
A mixture of modified difunctional isocyanate monomers.
(A2) Urethane prepolymer (a), which is a reaction product of 4,4'-MDI and a polyol requiring a polyether polyol, and
4,4'-MDI and
A mixture of a modified bifunctional isocyanate monomer and a bifunctional isocyanate monomer other than 4,4'-MDI.
(A3) Urethane prepolymer (a), which is a reaction product of an isocyanate component requiring 4,4'-MDI and a polyol requiring a polyether polyol, and
4,4'-MDI and
With bifunctional isocyanate monomers other than 4,4'-MDI,
A mixture of modified difunctional isocyanate monomers.

The polyol for forming the urethane prepolymer (a) will be described.
The polyol contains a polyether polyol as an essential component, and can also contain a polyester polyol. Since a polyether polyol generally has a lower viscosity in a molten state than a polyester polyol, it is a polyol when forming a urethane prepolymer in the polyisocyanate component (A) which is a constituent component of a solvent-free adhesive composition. It is important that the polyether polyol is essential. Further, by using the polyester polyol in combination, the compatibility with the polyol component (B) described later can be enhanced, and the cohesive force of the adhesive layer can be enhanced.
When a polyester polyol is used in combination, it is preferably 50% by mass or less in terms of the viscosity of the adhesive composition in 100% by mass of the polyol.

As the polyether polyol, for example, an oxylan compound such as ethylene oxide, propylene oxide, butylene oxide or tetrahydrofuran is polymerized using a low molecular weight polyol such as water, ethylene glycol, propylene glycol, trimethylolpropane or glycerin as an initiator. Examples thereof include the obtained polyether polyol.

As the polyether polyol, a material having three or more functions can be used in addition to the bifunctional one. Further, a plurality of those having different functional groups can be used in combination.
The polyether polyol preferably has a number average molecular weight of 100 or more and 5000 or less. Further, a plurality of products having different molecular weights can be used in combination.

Examples of the polyester polyol include a polyester polyol obtained by reacting a polyvalent carboxylic acid component with a glycol component.
Examples of the polyvalent carboxylic acid component include polyvalent carboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, azelaic acid, and sebatic acid, dialkyl esters thereof, or mixtures thereof. Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylol heptane, and poly. Examples thereof include glycols such as oxyethylene glycol, polyoxypropylene glycol, and polytetramethylene ether glycol, or mixtures thereof.

Examples of the low molecular weight diol include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and 3,3'-dimethylol heptane. Examples thereof include low molecular weight diols such as 2-methyl-1,3-propanediol and mixtures thereof.

As described above, the polyisocyanate component (A) in the present invention contains a urethane prepolymer (a) having an isocyanate group and 4,4'-MDI. The isocyanate monomer may be the unreacted isocyanate monomer remaining when the urethane prepolymer (a) is obtained, or may be added after the urethane prepolymer (a) is obtained.
The polyisocyanate component (A) preferably has a number average molecular weight of 200 to 1000, and more preferably has a number average molecular weight of 500 or more and 900 or less. Although the polyisocyanate component (A) contains the urethane prepolymer (a), it preferably exhibits the above molecular weight by containing 4,4'-MDI and the like.

As described above, the polyisocyanate component (A) in the present invention contains a modified product of a bifunctional isocyanate monomer.
The modified product of the bifunctional isocyanate monomer used in the present invention is a trimer of the bifunctional isocyanate monomer, a bullet body in which water is added to the bifunctional isocyanate monomer, and a polyfunctional or higher bifunctional isocyanate monomer. It is selected from the group consisting of adducts to which valent alcohol is added.
Examples of the bifunctional isocyanate monomer include, for example.
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, aliphatic diisocyanates such as 2,6-diisocyanate methylcaproate,
1,4-Cyclohexanediisocyanate, 1,3-Cyclohexanediisocyanate, 3-Isocyanatemethyl-3,5,5-trimethylcyclohexylisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), methyl2,4-cyclohexanediisocyanate, methyl2 , 6-Cyclohexanediisocyanate, 1,4-bis (isocyanatemethyl) cyclohexane, 1,3-bis (isocyanatemethyl) cyclohexane and other alicyclic diisocyanates,
m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate or a mixture thereof, 4 , 4'-Toluene diisocyanate, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate and other aromatic diisocyanates,
1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,3- or 1,4-bis (1-isocyanate-1-methylethyl) benzene Or an aromatic aliphatic diisocyanate such as a mixture thereof,
Triphenylmethane-4,4', 4'''-triisocyanate, 1,3,5-triisocyanate benzene, organic triisocyanate such as 2,4,6-triisocyanate toluene, 4,4'-diphenyldimethylmethane Examples thereof include polyisocyanate monomers such as organic tetraisocyanates such as -2,2'-5,5'-tetraisocyanate.

'
Examples of the bifunctional or higher functional alcohol for forming the adduct form include ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. 2,3-Butanediol, 1,2-Pentanediol, 1,5-Pentanediol, 1,2-Hexanediol, 1,6-Hexanediol, 1,2-Heptanediol, 1,5-Heptanediol, 1 , 7-Heptanediol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanediol, xylitol, sorbitol, pentaesritol and the like.

Further, the polyisocyanate component (A) used in the present invention preferably contains an isocyanate group in an amount of 10% by mass or more and less than 21% by mass.
When the isocyanate group content of the polyisocyanate component (A) is within the above range, a laminate having a better appearance can be formed when a film substrate having a high gas barrier property is used. The isocyanate group content (mass%) is determined by titration with hydrochloric acid as described later.

The proportions of 4,4'-MDI, 2,4'-MDI, TDI, XDI, and IPDI contained in the polyisocyanate component (A) are 4,4'-MDI and 2,4'-MDI, respectively. , TDI, XDI, IPDI total 100 mol%,
It is preferable that 4,4'-MDI is 25 mol% or more and 100 mol% or less.
When the composition ratio of 4,4'-MDI is in the above range, the coating appearance of the ink portion in the laminate can be improved and good adhesive performance can be exhibited without controlling the aging temperature to 31 ° C. or higher. .. If only 2,4'-MDI, TDI, XDI, and IPDI are used, sufficient adhesive performance cannot be exhibited by short-time aging.

Next, the polyol component (B) contained in the adhesive composition in the present invention will be described.
The polyol component (B) contains 70 to 100% by mass of a polyether polyurethane polyol having a number average molecular weight of 200 or more and 3000 or less in 100% by mass. The polyether polyurethane polyol is a reaction product obtained by reacting a polyether polyol with an isocyanate component such as 4,4'-MDI, 2,4'-MDI, or TDI under a condition of excess polyol.
By using the polyether polyurethane polyol as an essential material, the coating appearance of the ink portion can be improved and good adhesive performance can be exhibited. By using the polyol component (B) containing a polyether polyurethane polyol within the above range, a laminate having a good appearance can be obtained when a film substrate having a high gas barrier property is used and coated and bonded at high speed. Moreover, good adhesive performance can be exhibited.

The polyether polyol which is an essential raw material of the polyether polyurethane polyol will be described. Examples of the polyether polyol include a polyether diol and a polyether triol.
As the polyether diol, for example, a poly obtained by polymerizing an oxylan compound such as ethylene oxide, propylene oxide, butylene oxide or tetrahydrofuran, using a bifunctional low-volume polyol such as water, ethylene glycol or propylene glycol as an initiator. Examples include ether diol.
Examples of the polyether triol include a polyether triol obtained by polymerizing an oxylan compound such as ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran, using a low amount triol such as trimethylolpropane and glycerin as an initiator. ..

The polyol component (B) may contain other polyol components such as polyester polyol in addition to the polyether polyurethane polyol as long as the object of the present invention is not impaired.
Examples of the polyester polyol include polyvalent carboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, azelaic acid, and sebatic acid, dialkyl esters thereof, or mixtures thereof, and examples thereof include ethylene glycol, propylene glycol, diethylene glycol, and butylene glycol. , Neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylol heptane, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol and other glycols Examples thereof include polyester polyols obtained by reacting with or a mixture thereof, or polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly (β-methyl-γ-valerolactone). Be done.
In addition, vegetable oils such as castor oil and polyester compounds derived from vegetable oils can also be used.

Typical vegetable oils are asa seed oil, flaxseed oil, eno oil, oyster oil, olive oil, cacao oil, capoc oil, kaya oil, mustard oil, kyonin oil, drilling oil, kukui oil, walnut oil, poppy oil, sesame oil. , Saflower oil, Daikon seed oil, soybean oil, large wind child oil, camellia oil, corn oil, rapeseed oil, niger oil, nuka oil, palm oil, sunflower oil, sunflower oil, grape seed oil, gentle oil, pine seed oil , Cotton seed oil, palm oil, peanut oil, dehydrated castor oil and the like.

It is also possible to use a product obtained by further reacting a part of the hydroxyl groups in the polyol component (B) such as a polyether polyurethane polyol or a polyester diol with an acid anhydride such as trimellitic anhydride.
By using the polyol component (B) to which an acid anhydride is added, the adhesion can be improved when applied to a sheet-like substrate which is difficult to adhere. The amount of trimellitic anhydride or the like to be added is preferably 0.1 to 5% by mass based on 100% by mass of the polyol component (B).

Further, the polyol component (B) may further contain a diol having a number average molecular weight of 50 or more and less than 500.
For example, polyester diol, polyether diol, polyether ester diol, polyester amide diol, acrylic diol, polycarbonate diol, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl- Examples thereof include low molecular weight diols such as 1,5-pentanediol, 3,3'-dimethylol heptane, 2-methyl-1,3-propanediol, and mixtures thereof. Among these, low molecular weight diols are preferable from the viewpoint of reactivity.

Examples of the polyether ester polyol include a poly obtained by reacting a dibasic acid such as terephthalic acid, isophthalic acid, adipic acid, azelaic acid, and sebatic acid, a dialkyl ester thereof, or a mixture thereof with the above-mentioned polyether diol. Examples include ether ester diols.

The polyester amide diol can be obtained by using, for example, an aliphatic diamine having an amino group such as ethylenediamine, propylenediamine, and hexamethylenediamine as a raw material in the above esterification reaction.

Examples of acrylic diols include hydroxyethyl acrylate, hydroxyprople acrylate, acrylic hydroxybutyl, etc., which contain one or more hydroxyl groups in one molecule, or their corresponding methacrylic acid derivatives, such as acrylic acid, methacrylic acid, and the like. It is obtained by copolymerizing with an acid or an ester thereof.

Examples of the polycarbonate diol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and 1,9-nonane. Diol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, one or more glycols selected from dimethyl Examples thereof include those obtained by reaction with carbonate, diphenyl carbonate, ethylene carbonate, phosgen and the like.

Examples of low-molecular-weight triols include low-molecular-weight triols such as castor oil, trimethylolpropane, and glycerin, or mixtures thereof. Among these, low molecular weight triols and polyether triols are preferable from the viewpoint of reactivity.

In the adhesive composition of the present invention, when the number of moles of hydroxyl groups in the polyol component (B) is 100 mol, the number of moles of isocyanate groups in the polyisocyanate component (A) is 120 mol or more and 400 mol or less. Is preferable.
When the number of moles of hydroxyl groups in the polyol component (B) is 100 moles, the number of moles of isocyanate groups in the polyisocyanate component (A) is within the above range, so that it is good even if it is aged under high humidity. Can develop adhesive strength.

The adhesive composition in the present invention contains 4,4'-MDI, 2,4'-MDI, HDI, TDI, which is contained in a total of 100% by mass of the polyisocyanate component (A) and the polyol component (B). The total amount of IPDI and XDI is 10 to 34% by mass, preferably 12 to 30% by mass.
The total amount of 4,4'-MDI, 2,4'-MDI, HDI, TDI, IPDI, and XDI contained in the total 100% by mass of the polyisocyanate component (A) and the polyol component (B) is in the above range. By being inside, a laminate having a better appearance can be obtained when a film base material having a high gas barrier property is used.

The adhesive composition in the present invention can further contain particles having an average particle size of 1 × 10 ^-4 mm or more and 4 × 10 ^{-4 mm or less.} By containing particles having an average particle size within the above range, a film base material having a high gas barrier property can be used, and a laminated body having a better appearance can be obtained when coating and laminating at high speed. If the particles are too small, the flow characteristics do not change much even if they are added, so the appearance does not change much.
Here, the average particle size is an average volume diameter, which is a value obtained by a laser light scattering method.

As such particles, either an inorganic compound or an organic compound can be used, and they may be used alone or in combination of two or more.

Examples of the particles of the inorganic compound include aluminum oxide, aluminum silicate, aluminum hydroxide, alumina white, potassium sulfate, zinc oxide, zinc carbonate, magnesium aluminometasilicate, magnesium silicate, magnesium oxide, magnesium carbonate, and hydroxide. Magnesium, barium titanate, barium sulfate, barium carbonate, calcium carbonate, calcium hydroxide, calcium oxide, calcium silicate, calcium sulfite, calcium sulfate, titanium oxide, silica, zeolite, activated charcoal, kaolin, talc, brazing clay, silicate Examples include powders of stone, mica, graphite, cericite, montmorillonite, cericite, sepiolite, bentonite, pearlite, zeolite, wallastonite, fluorite, dolomite and the like. Among these, silica and talc are prized.

Examples of the particles of the organic compound include benzoguanamine resin, silicon resin, styrene resin, crosslinked polystyrene, epoxy resin, phenol resin, fluororesin, polyethylene resin, polyester resin, polyimide resin, polyamide resin, polyacetal resin, polyurethane resin, and acetic acid. Examples thereof include powders of vinyl copolymer resin, polyphenylene oxide resin, nylon 6, nylon 12, cellulose, acrylic resin, methacrylic resin and the like. Among these, benzoguanamine resin is used as an award.

^{The content of the particles is such that the average particle size is 1 × 10 -4} mm or more and 4 × 10 ^-4 mm or less with respect to 100 parts by mass of the total of the polyisocyanate component (A) and the polyol component (B). C) is preferably contained in an amount of 0.01 to 10 parts by mass. Within the above range, the appearance and the adhesive strength can be improved in a well-balanced manner.

The particles can be mixed at the same time as the polyisocyanate component (A) and the polyol component (B), or can be mixed with either one component and the other. The particles are preferably premixed with the polyol component (B) component.

The adhesive composition in the present invention preferably does not contain a solvent, and each component is preferably blended at a low temperature as much as possible within a range where fluidity can be ensured, specifically at 25 ° C. or higher and 80 ° C. or lower. It is preferable to mix. The viscosity at 60 ° C. immediately after mixing the polyisocyanate component (A) and the polyol component (B) is preferably 50 mPa · s or more and 5000 mPa · s or less, and more preferably 50 mPa · s or more and 3000 mPa · s or less. is there.
In the present invention, immediately after mixing means within 1 minute after uniform mixing, and the melt viscosity indicates a value obtained by a B-type viscometer. If the melt viscosity at 60 ° C is over 5,000 mPa · s, coating becomes difficult and it is difficult to secure good workability, and if the coating temperature is 60 ° C or less, a good coating appearance may not be obtained. There is.
On the other hand, if the melt viscosity at 60 ° C. is less than 50 mPa · s, sufficient adhesive performance cannot be obtained due to the weak initial cohesive force, or the thickness of the coating film becomes uniform when the adhesive composition is applied to the base material. It tends to cause poor appearance or warpage.

The adhesive composition in the present invention further requires additives such as antioxidants, UV absorbers, hydrolysis inhibitors, fungicides, thickeners, plasticizers, defoamers, pigments and fillers. Can be used accordingly.
Further, in order to further enhance the adhesive performance, an adhesive auxiliary such as a silane coupling agent, phosphoric acid, a phosphoric acid derivative, an acid anhydride, or an adhesive resin can be used. In addition, known catalysts, additives and the like can be used to control the curing reaction.

As the silane coupling agent, one having a functional group such as a vinyl group, an epoxy group, an amino group, an imino group and a mercapto group and a functional group such as a methoxy group and an ethoxy group can be used.
For example, chlorosilane such as vinyltrichlorosilane, aminosilane such as N- (dimethoxymethylsilylpropyl) ethylenediamine, N- (triethoxysilylpropyl) ethylenediamine, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxy. Examples thereof include epoxysilane such as silane and vinylsilane such as vinyltriethoxysilane.
The amount of the silane coupling agent added is preferably 0.1 to 5% by mass with respect to the total adhesive composition.

Among the phosphorus oxygen acids or derivatives thereof used in the present invention, the phosphorus oxygen acids may be any as long as they have at least one free oxygen acid, for example, hypophosphoric acid. Examples thereof include phosphoric acids such as phosphite, orthophosphoric acid and hypophosphoric acid, and condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid and ultraphosphoric acid. Examples of the derivative of the oxygen acid of phosphorus include those in which the oxygen acid of phosphorus is partially esterified with alcohols in a state where at least one free oxygen acid is left. Examples of these alcohols include fatty alcohols such as methanol, ethanol, ethylene glycol and glycerin, and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol and fluoroglycinol. As the oxygen acid of phosphorus or a derivative thereof, one kind or two or more kinds may be used. The amount of phosphorus oxygen acid or a derivative thereof added is 0.01 to 10% by mass, preferably 0.05 to 5% by mass, and more preferably 0.1 to 1% by mass with respect to the total composition.

An ester (C) of a monohydric alcohol and a carboxylic acid contained in the adhesive composition of the present invention, which is liquid at 25 ° C., will be described.
The monohydric alcohol preferably has 1 to 20 carbon atoms, and more preferably 3 to 10 carbon atoms.
For example, propyl alcohol, isopropur alcohol, butyl alcohol, isobutyl alcohol, pentyl alcohol, isopentyl alcohol, hexyl alcohol, isohexyl alcohol, heptyl alcohol, isoheptyl alcohol, octyl alcohol, isooctyl alcohol, nonyl alcohol, isononyl alcohol, Decyl alcohol, isodecyl alcohol,
Undecyl alcohol, Isoundecyl alcohol, Dodecyl alcohol, Isododecyl alcohol, Tridecyl alcohol, Isotridecyl alcohol, Tetradecyl alcohol, Isotetradecyl alcohol, Pentadecyl alcohol, Isopentadecyl alcohol, Hexadecyl alcohol, Isohexadecyl Examples thereof include alcohols, heptadecyl alcohols, isoheptadecyl alcohols, octadecyl alcohols, isooctadecil alcohols, nonadesyl alcohols, isononadecyl alcohols, icosyl alcohols, isoicosyl alcohols and the like.

Examples of the carboxylic acid include propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, pelargonic acid, caproic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, and benzoic acid. Examples thereof include carboxylic acids, dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid and phthalic acid. As the carboxylic acid, it is preferable to use the above-mentioned dicarboxylic acid or the like.

In the present invention, the liquid at 25 ° C. means a viscosity of 10,000 mPa · s or less when the viscosity is measured using a B-type viscometer while the ester (C) is held at 25 ° C.

The content of the ester (C) liquid at 25 ° C. is 0.1 to 20 parts by mass, preferably 0.5 parts by mass, based on 100 parts by mass of the total of the polyisocyanate component (A) and the polyol component (B). It is 10 parts by mass. Further, the liquid ester (C) may be used alone or in combination of two or more.
By containing 0.1 to 20 parts by mass of the ester (C), the adhesive layer can be smoothed and the adhesion to the ink layer can be ensured, so that the adhesive composition is applied at high speed. However, a laminate having a good appearance of the printed portion can be obtained by aging at a low temperature of 40 ° C. or lower and for a short time.

The laminated body of the present invention will be described. As described above, the laminate of the present invention has the transparent base material 1, the ink layer, the adhesive layer, and the base material 2 in this order.

The transparent base material 1 includes polyolefins such as polyethylene and polypropylene, polyethylene terephthalate (hereinafter, also referred to as PET), polyesters such as polycarbonate and polylactic acid, polystyrene resins such as polystyrene, AS resin and ABS resin, nylon, polyamide and poly. There are films or sheets made of vinyl chloride, polyvinyl chloride, cellophane, paper, aluminum, etc., or composite materials of these, which are applied using the above printing method and dried or cured by drying in an oven. By fixing, a printed matter can be obtained. The surface of the base material may be coated with a metal oxide or the like by vapor deposition coating and / or coated with polyvinyl alcohol or the like, and may be further subjected to a surface treatment such as corona treatment.

The ink layer is not particularly limited, and printing can be performed by a known printing method such as gravure printing or flexographic printing, but printing by a gravure printing method is particularly preferable. As the cylinder used for gravure printing, known cylinders such as engraving type and corrosion type are used.
The ink composition diluted with a diluting solvent to a viscosity and concentration suitable for gravure printing is supplied to each printing unit alone or mixed, and after printing, it is passed through an oven to be dried or cured to form an ink layer. It is formed. The oven temperature is usually 40-80 ° C. and the printing speed is usually 50-300 m / min. The ink layer is usually 0.5 to 5 g / m ² , preferably ¹ to 3.5 g / m 2.

The adhesive layer contains the polyisocyanate component (A), the polyol component (B), and the ester (C) liquid at 25 ° C., as described above, with the polyisocyanate component (A) and the polyol component (B). The ester (C) is contained in a total of 100% by mass of the polyisocyanate component (A) and the polyol component (B) so as to be 0.1 to 20 parts by mass with respect to a total of 100 parts by mass. , 4,4'-MDI, 2,4'-MDI and TDI are a cured product of an adhesive composition mixed so as to have a total amount of 10 to 34% by mass, and can be obtained by, for example, the following method. Can be done.
That is, the adhesive composition is applied on the ink layer or on ^{the base material 2 having an oxygen permeability of 100 CC (m 2} , 24 hr, 1 atm, 25 ° C.) or less to form a precursor of the adhesive layer. To do. The coating amount of the adhesive composition is appropriately selected depending on the type of the base material 2, the coating conditions, and the like, but is usually 1 to 5 ^{g / m 2} , preferably 1.5 to 4.5 g / m. It is ^2.
After that, the base material 2 having an oxygen permeability of 100 CC (m ² , 24 hr, 1 atm, 25 ° C.) or less is overlaid on the precursor of the adhesive layer, or the ink layer, that is, the transparent base material 1 is placed on the precursor of the adhesive layer. After overlapping the surfaces of the white ink layer provided in the above that are not in contact with the transparent base material 1, the precursor is cured by aging at room temperature or under heating to form an adhesive layer, and the laminate is formed. To manufacture. In the case of the adhesive composition of the present invention, the time required for aging is about one day. Further, in the case of the adhesive composition of the present invention, sufficient adhesive performance can be exhibited even if the environmental humidity during coating to aging is high.

The base material 2 used has an oxygen permeability of 100 CC (m ² , 24 hr, 1 atm, 25 ° C.) or less. Oxygen permeability is affected by thickness. In the present application, a substrate 2 having an oxygen permeability of 100 CC or less can be used as the base material 2 based on the oxygen permeability (hereinafter referred to as oxygen permeability coefficient) and the thickness per unit thickness (1 μm).
For example, an ethylene-vinyl alcohol copolymer having an ethylene content of 56% ^{can be used even at 1 μm because the oxygen permeability coefficient (m 2} , 24 hr, 1 atm, 25 ° C.) is 3 CC.
On the other hand, a plastic film having a large oxygen permeability coefficient as shown below can also be used depending on the film thickness. That is, since the acrylonitrile copolymer having an acrylonitrile content of 70% has an oxygen permeability coefficient of 300 CC, it can be used if the film thickness is 3 μm or more.
Similarly
A vinylidene chloride copolymer having an oxygen permeability coefficient of 400 CC has a film thickness of 4 μm or more.
Nylon 6 having an oxygen permeability coefficient of 1700 CC has a film thickness of 17 μm or more.
Nylon 66 having an oxygen permeability coefficient of 1925 CC has a film thickness of 19.25 μm or more.
Polyethylene terephthalate having an oxygen permeability coefficient of 768 CC has a film thickness of 7.68 μm or more.
The terephthalic acid-bisphenol copolymer polyarylate having an oxygen permeability coefficient of 2580 CC has a film thickness of 25.8 μm or more.
A polyacetal having an oxygen permeability coefficient of 4850 CC should have a film thickness of 48.5 μm or more.
Polychlorotrifluoroethylene having an oxygen permeability coefficient of 650 CC has a film thickness of 6.5 μm or more.
Polyvinylidene fluoride having an oxygen permeability coefficient of 1300 CC has a film thickness of 13 μm or more.
Each can be used as a base material 2.

Further, a vapor-deposited film obtained by depositing aluminum, silicon oxide, aluminum oxide or the like on various plastic films can also be used as the base material 2. In many cases, the thickness of the thin-film deposition layer is about 1 to 500 nm, and by providing such a thin-film deposition layer, the influence of the type and thickness of the plastic film on the oxygen permeability becomes extremely small.
For example, a non-stretched polypropylene film provided with an aluminum vapor deposition layer has an oxygen permeability of 20 to 10 CC (m ² , 24 hr, 1 atm, 25 ° C.).
A polyethylene terephthalate film provided with an aluminum vapor deposition layer has an oxygen permeability of ² to 0.3 CC (m 2, 24 hr, 1 atm, 25 ° C.).
A polyethylene terephthalate film provided with an aluminum oxide vapor deposition layer has an oxygen permeability of 4 to 0.5 CC (m ² , 24 hr, 1 atm, 25 ° C.).
A polyethylene terephthalate film provided with a silicon oxide vapor deposition layer has an oxygen permeability of 5 to 0.3 CC (m ² , 24 hr, 1 atm, 25 ° C.) and is used as the base material 2, respectively.
Further, as the metal foil, the metal foil such as stainless steel, iron, copper, and lead has an oxygen permeability of 0 CC (m ² , 24 hr, 1 atm, 25 ° C.) regardless of the thickness.
As the base material 2, a material in which a vapor-deposited layer is provided on various plastic films or a metal foil is preferable, and a material in which metal is vapor-deposited on various plastic films (hereinafter, also referred to as a vapor-deposited film) is preferable. The metal vapor deposition layer is preferably in contact with the adhesive layer.

The oxygen permeability can be determined according to the method of JISK7126 using an oxygen permeability measuring device. For example, the MOCON oxygen permeability measuring device (ОX-TRAN2 / 21) manufactured by Hitachi High-Technologies Corporation produces a current proportional to the amount of oxygen passing through the sample as a carrier gas (OX-TRAN2 / 21).
It is a device equipped with a coulometric sensor generated by nitrogen), measures the voltage change through a standard load resistor, and converts it into oxygen permeability.

Hereinafter, the present invention will be described in more detail with reference to Examples. All% and parts in Examples and Comparative Examples are based on mass unless otherwise specified.

<Measurement method of mass average molecular weight (Mw) and number average molecular weight (Mn)>
The mass average molecular weight (Mw) and the number average molecular weight (Mn) were measured by using GPC (gel permeation chromatography) "Shodex GPC System-21" manufactured by Showa Denko KK. GPC is a liquid chromatography in which a substance dissolved in a solvent is separated and quantified by the difference in its molecular size. The solvent is tetrohydrofuran, and the molecular weight is determined in terms of polystyrene.

<Measurement method of hydroxyl value>
Approximately 1 g of the sample was precisely weighed in an Erlenmeyer flask with a stopper, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution was added and dissolved. Further, exactly 5 ml of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 ml) was added, and the mixture was stirred for about 1 hour. Phenolphthalein TS is added as an indicator to this and lasts for 30 seconds. Then, it was titrated with 0.1N alcoholic potassium hydroxide solution until the solution became pink.
The hydroxyl value was determined by the following (Equation 1). The hydroxyl value was taken as the value of the dry state of the resin (unit: mgKOH / g).
(Equation 1) Hydroxy group value (mgKOH / g) = [{(ba) × F × 28.25} / S] / (nonvolatile content concentration / 100) + D
However, S: sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
b: Consumption (ml) of 0.1N alcoholic potassium hydroxide solution in the blank experiment
F: Titer of 0.1N alcoholic potassium hydroxide solution
D: Acid value (mgKOH / g)

<Measurement method of acid value>
Approximately 1 g of the sample was precisely weighed in an Erlenmeyer flask with a stopper, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution was added and dissolved. Phenolphthalein TS was added as an indicator, held for 30 seconds, and then titrated with a 0.1 N alcoholic potassium hydroxide solution until the solution turned pink.
The acid value was determined by the following (Equation 2). The acid value is the value of the dry state of the resin (unit: mgKOH / g).
(Formula 2) Acid value (mgKOH / g) = {(5.611 × a × F) / S} / (nonvolatile content concentration / 100)
However, S: sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Titer of 0.1N alcoholic potassium hydroxide solution

<Measuring method of NCO content (mass%)>
About 1 g of the sample was precisely weighed in a 200 mL Erlenmeyer flask, and 10 mL of 0.5N di-n-butylamine (toluene solution) and 10 mL of toluene were added thereto to dissolve the sample. A phenolphthalein test solution was added as an indicator, held for 30 seconds, and then titrated with a 0.25N hydrochloric acid solution until the solution turned pink.
NCO (mass%) was determined by the following (Equation 3).
(Equation 3) NCO (mass%) = {(ba) × 4.202 × F × 0.25} / S
However, S: sample collection amount (g)
a: Consumption of 0.25N hydrochloric acid solution (ml)
b: Consumption of 0.25N hydrochloric acid solution in blank experiment (ml)
F: Titer of 0.25N hydrochloric acid solution

Synthesis of polyisocyanate component (α) for adhesive composition (Synthesis Example 101)
129 parts of polypropylene glycol with a number average molecular weight of about 400 (hereinafter referred to as PPG-400), 1018 parts of polypropylene glycol with a number average molecular weight of about 2000 (hereinafter referred to as PPG-2000), and a number average molecular weight of about 400 with polypropylene glycol added to glycerin. 85 parts of triol (hereinafter referred to as PPG-400-3 functional) and 670 parts of 4,4'-MDI are charged in a reaction vessel and heated at 70 ° C. to 80 ° C. for 3 hours while stirring under a nitrogen gas stream to form urethane. The reaction was carried out to obtain a polyisocyanate composition α- (1) containing polyurethane polyisocyanate (a) and unreacted 4,4-diphenylmethane diisocyanate.
The composition α- (1) had an isocyanate group content of 6.9% and an MDI monomer content of 23%.

(Synthesis Example 102)
477 parts of adipic acid (hereinafter referred to as ADA) and 323 parts of propylene glycol were charged into a reaction vessel and heated to 150 ° C. to 240 ° C. while stirring under a nitrogen gas stream to carry out an esterification reaction. When the acid value reaches 1.3 (mgKOH / g), the reaction temperature is set to 200 ° C., the inside of the reaction vessel is gradually depressurized, and the reaction is carried out at 1.3 kPa or less for 30 minutes, and the acid value is 0.3 (mgKOH / g). ), A hydroxyl value of 56.1 (mgKOH / g), and a number average molecular weight of about 2000, polyesterdiol 1 having hydroxyl groups at both ends was obtained.
222 parts of the obtained polyester diol 1, 112 parts of PPG-400, 666 parts of PPG-2000, 72 parts of PPG-400-3 functional, 800 parts of 4,4'-MDI were charged into a reaction vessel, and nitrogen was charged. A polyisocyanate composition α-containing polyurethane polyisocyanate (a) and unreacted 4,4'-diphenylmethane diisocyanate by heating at 70 ° C. to 80 ° C. for 3 hours with stirring under a gas stream to carry out a urethanization reaction. (2) was obtained.
The composition α- (2) had an isocyanate group content of 10.3% and an MDI monomer content of 28%.

(Synthesis Example 103-104)
According to the composition shown in Table 1, polyisocyanate α- (3) and polyisocyanate α- (4), which are polyether polyurethane polyisocyanate resins, were obtained in the same manner as in Synthesis Example 101 and Synthesis Example 102.

(Formulation Example 201)
The polyisocyanate composition α- (1) obtained in Synthesis Example 101: 700 parts, 200 parts of the HDI burette body, and 100 parts of 2,4'-MDI were mixed to obtain a polyisocyanate component A- (1).

(Formulation Examples 201-209)
Polyisocyanate components A- (2) to A- (9) were obtained in the same manner as in Formulation 301 according to the composition shown in Table 2.

Synthesis of polyether polyurethane polyol component for adhesive composition (Synthesis Example 301)
400 parts of PPG-400, 200 parts of PPG-2000, 400 parts of PPG-400-3 functional, and 145 parts of 4,4'-MDI are charged in the reaction vessel, and the temperature is increased from 70 ° C. while stirring under a nitrogen gas stream. The urethanization reaction was carried out by heating at 80 ° C. for 3 hours to obtain a polyether polyurethane polyol having a number average molecular weight of 500 and a hydroxyl value of 220 (mgKOH / g). Hereinafter, this resin will be referred to as a polyether polyurethane polyol b1- (1).

(Synthesis Examples 302 and 303)
According to the composition shown in Table 3, a polyether polyurethane polyol b1- (2) and a polyether polyurethane polyol b1- (3) were obtained in the same manner as in Synthesis Example 301.

(Formulation Example 403)
90 parts of the polyether polyurethane polyle b1- (1) and 10 parts of diethylene glycol obtained in Synthesis Example 301 were mixed to obtain a polyol component B- (3).

(Formulation Example 404)
208 parts of adipic acid and 192 parts of diethylene glycol were charged in a reaction vessel, and the esterification reaction was carried out by heating to 150 ° C. to 240 ° C. with stirring under a nitrogen gas stream. When the acid value reaches 1.3 (mgKOH / g), the reaction temperature is set to 200 ° C., the inside of the reaction vessel is gradually depressurized, and the reaction is carried out at 1.3 kPa or less for 30 minutes, and the acid value is 0.5 (mgKOH / g). ), The hydroxyl value was 56.1 (mgKOH / g), and the polyester diol 2 having hydroxyl groups at both ends having a number average molecular weight of about 2000 was obtained.
70 parts of the polyether polyurethane polyle b1- (1) obtained in Synthesis Example 301 and 2:30 parts of the polyester diol were mixed to obtain a polyol component B- (4).

(Formulation Example 407)
60 parts of the polyether polyurethane polyle b1- (1) obtained in Synthesis Example 301 and 2:40 parts of the polyester diol were mixed to obtain a polyol component B- (7).

なお、合成例３０１、３０２で得たポリエーテルポリウレタンポリールｂ１−(１)、ｂ１−（２）をそのまま用いる場合を、配合例を示す表４では、便宜上ポリオール成分Ｂ−（１）、Ｂ−（２）と表現する。

In addition, in the case where the polyether polyurethane polyres b1- (1) and b1- (2) obtained in Synthesis Examples 301 and 302 are used as they are, in Table 4 showing the formulation example, the polyol components B- (1) and B are shown for convenience. -Expressed as (2).

(Example 1)
100 parts of the polyisocyanate component A- (1) obtained in Formulation Example 201, 50 parts of the polyol component B- (1) obtained in Formulation Example 401, and adipic acid which is liquid at 25 ° C. as the ester C- (1). 1.5 parts of diisopropyl was mixed at 60 ° C. to obtain a solvent-free adhesive composition AD1. A laminate was obtained for AD1 according to the method described later, and the appearance and strength of the laminate were evaluated.
The solvent-free adhesive composition AD1 contains 156 mol of isocyanate groups derived from the polyisocyanate component A- (1) with respect to 100 mol of hydroxyl groups in the polyol component.
The amount of isocyanate group with respect to 100 mol of hydroxyl group is determined as follows.
Amount of isocyanate group per 100 mol of hydroxyl group = [isocyanate group (eq.) / Hydroxyl group (eq.)] × 100
Isocyanate group (eq.) = NCO content (% by mass) / (42 x 100)
Hydroxy group (eq.) = Hydroxy group value / 56100

Further, 4,4'-MDI, 2,4'-MDI, 2,2'-MDI, TDI, HDI, IPDI (hereinafter referred to as isocyanate monomer) contained in 100% of the solvent-free adhesive composition. The total rate of was 17.3%.
The isocyanate monomer content is the sum of the peak area derived from MDI monomer and IPDI monomer around Mn = 200 to 300 and the peak area derived from TDI monomer and HDI monomer around Mn = 100 to 200 observed on the GPC chart. The area is divided by the total area of all peaks observed on the GPC chart.
Isocyanate monomer content (%) = (total peak area of isocyanate monomer / total area of all peaks) x 100

Further, the solvent-free adhesive composition AD1 is an esterified product of a compound having a carboxyl group and a monohydric alcohol with respect to a total of 100 parts by mass of a polyisocyanate component and a polyol component, and is liquid at 25 ° C. Contains 1 part by mass of ester.

(Examples 2 to 24) (Comparative Examples 1 to 13)
Adhesive compositions AD2-24 and AD25-37 were obtained in the same manner as in Example 1 according to the compositions shown in Tables 5-7.
For convenience of comparison, Examples 1 and 12 are also shown in Tables 6 and 7, respectively.

[Preparation of laminate]
Using a solvent-free test coater, the solvent-free adhesive compositions AD1 to AD37 obtained in each Example and Comparative Example were applied to the surface of the ink layer printed on the ОPP film at a temperature of 60 ° C. and a coating speed of 200 m /. It is coated in minutes (coating amount: 2 g / m ² ), and an aluminum-deposited unstretched polypropylene film (hereinafter referred to as VMCPP) having an oxygen permeability of 20 CC (m ^{2, 24 h, 1 atm, 25 ° C.) is applied to the coated surface.} (S: 25 μm.) Was laminated to obtain a laminated body (pre-laminated body) in the preparatory stage.
These pre-laminates were aged for 1 day in an environment of 25 ° C. and 80% RH to cure the adhesive layer, and a laminate was prepared. With respect to the obtained laminated body, the adhesive strength of the laminated body and the interface state of the laminated body were evaluated according to the following method. The results are shown in Tables 5-7.

[Interfacial state (appearance) of laminated body]
The vapor-deposited portion was visually observed through the ink layer and the adhesive layer from the transparent substrate 1 side, and evaluated according to the following criteria. From the outside of the rolled roll, it was unwound until no small speckled pattern was observed, and the length of the unwound was measured and evaluated according to the following criteria. The pressure of the roll-shaped pre-laminated body increases toward the inside and decreases toward the outside. Therefore, pressure is applied to the adhesive layer during curing toward the inner side, so that the adhesive layer tends to get wet and spread, but the leveling property decreases toward the outer side. The length from the end of the roll until the small speckled pattern is no longer observed is an index of leveling property, and the shorter the time, the better the leveling property.
Less than 5: 15m 4: 15m or more, less than 20m 3: 20m or more, less than 25m
2:25 m or more, less than 30 m 1:30 m or more

[Adhesive strength]
After rewinding until no small speckled pattern was observed, the laminate was cut into a length of 300 mm and a width of 15 mm to obtain a test piece. Using an Instron type tensile tester, the tension was applied at a peeling speed of 300 mm / min in an environment of 25 ° C., and the T-type peel strength (N) between OPP and VMCPP was measured with a width of 15 mm. This test was performed 5 times, and the average value was calculated and evaluated according to the following criteria.
5: Adhesive strength 1.2N or more 4: Adhesive strength 0.9N or more and less than 1.2N 3: Adhesive strength 0.6N or more and less than 0.9N 2: Adhesive strength 0.3N or more and less than 0.6N 1: Adhesive strength Force less than 0.3N

As shown in Table 5, it can be seen that Examples 1 to 10 in which the adhesive layer is formed by the adhesive composition of the present invention are excellent in appearance and adhesive strength after aging at 25 ° C. for 1 day.
On the other hand, in Comparative Example 1, the isocyanate component A- containing the urethane prepolymer (a) obtained by using only 4, 4'-MDI as the isocyanate component (A) and 4, 4'-MDI. Since (8) is used, the reaction rate is too fast and the leveling property of the adhesive layer during curing is lowered, so that the appearance is not sufficient.
In Comparative Example 2, since 4, 4'-MDI was not used when obtaining the urethane prepolymer and only 2, 4'-MDI was used, the reaction rate was too slow and the temperature was 25 ° C. for 1 day. Later adhesive strength is not sufficient.
Since the polyol component (B) used in Comparative Example 3 was the polyol component B- (5), that is, the polyether polyurethane polyol b1- (3) having a mass average molecular weight of 3200, the smoothness at the time of coating was lowered. The appearance is poor.
In Comparative Example 4, since tripropylene glycol having a mass average molecular weight of 191 was used as the polyol component (B) as the polyol B- (6), the reaction rate with the isocyanate component (A) was too fast, and the adhesive during curing was in the process of curing. The appearance is not sufficient due to the reduced leveling of the layers.
In Comparative Example 5, since 40% of polyester polyol is used as the polyol component (B), the compatibility between the polyol component (B) and the polyisocyanate component (A) is lowered, so that the appearance is deteriorated.
In Comparative Example 6, since 34.2% of the isocyanate monomer is contained in the adhesive after blending, the appearance of the laminate after coating is not sufficient due to the permeation of the isocyanate component into the ink.

As shown in Table 6, it can be seen that Examples 1 and 11 to 19 in which the adhesive layer is formed by the adhesive composition of the present invention are excellent in appearance and adhesive strength after aging at 25 ° C. for 1 day. On the other hand, in Comparative Examples 7 to 9, since a solid ester was used at 25 ° C. instead of the liquid ester (C), a smooth adhesive layer could not be formed, the appearance of the laminated body was inferior, and the laminate appearance was poor. Adhesion to the ink layer is reduced, and adhesive performance is inferior.

As shown in Table 7, Examples 14 and 20 to 24 in which an adhesive layer was formed with the adhesive composition of the present invention using C- (3) as the liquid ester (C) were at 25 ° C. 1. It can be seen that the appearance and adhesive strength after day aging are excellent. On the other hand, Comparative Example 10 does not contain the liquid ester C- (3), and in Comparative Example 11, the content of the liquid ester C- (3) is as small as less than 0.1%, so that each is sufficiently sufficient. A smooth adhesive layer cannot be formed, and the appearance of the laminate is inferior. In Comparative Examples 12 to 13, since the amount of the liquid ester C- (3) was too large, the adhesive layer was rough and a smooth adhesive layer could not be formed, the appearance of the laminated body was poor, and the adhesive layer adhered to the ink layer. Poor property and poor adhesive performance.

Claims (4)

An adhesive composition containing a polyisocyanate component (A) and a polyol component (B), which satisfies all of the following conditions (1) to (7).
(1) An esterified product of a compound having a carboxyl group and a monohydric alcohol with respect to a total of 100 parts by mass of the polyisocyanate component (A) and the polyol component (B), which is a liquid esterified product at 25 ° C. C) is further contained in an amount of 0.1 to 20 parts by mass.
(2) The polyisocyanate component (A) contains a urethane prepolymer (a) having an isocyanate group and 4,4'-diphenylmethane diisocyanate.
(3) The polyisocyanate component (A) is a trimer of a bifunctional isocyanate monomer, a bullet body in which water is added to a bifunctional isocyanate monomer, and a bifunctional or higher polyhydric alcohol in the bifunctional isocyanate monomer. It further comprises a modified version of at least one bifunctional isocyanate monomer selected from the group consisting of added adducts.
(4) The polyisocyanate component (A) may further contain at least one isocyanate component selected from the group consisting of 2,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, and xylene diisocyanate. ..
(5) The urethane prepolymer (a) having an isocyanate group is a reaction product of 4,4'-diphenylmethane diisocyanate and a polyol requiring a polyether polyol.
(6) In 100% by mass of the polyol component (B), 70 to 100% by mass of a polyether polyurethane polyol having a number average molecular weight of 200 or more and 3000 or less is contained.
(7) The total amount of 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, and xylene diisocyanate contained in 100% by mass of the adhesive composition is It is 10 to 34% by mass. The adhesive composition according to claim 1, wherein the monohydric alcohol has 1 to 20 carbon atoms. The adhesive composition according to claim 1 or 2, wherein the esterified product (C) liquid at 25 ° C. is a diester of a compound having two carboxyl groups and a monohydric alcohol. A laminate having a transparent base material 1, an ink layer, an adhesive layer, and ^{a base material 2 having an oxygen permeability of 100 CC (m 2} , 24 hr, 1 atm, 25 ° C.) or less in this order.
The adhesive layer is a cured product of the adhesive composition according to any one of claims 1 to 3.
Laminated body.