JP2023022367A - Solvent-free adhesive, laminate and package - Google Patents

Abstract

To provide: a solvent-free adhesive which materializes superior adhesive strength and heat seal strength (heat resistance) of a metal deposition layer interface and is excellent in coating performance; and a laminate and a package which are excellent in adhesive strength and heat seal strength of the interface, and excellent in appearance.SOLUTION: A solvent-free adhesive is provided, including: polyol compound; and a polyisocyanate compound including polyisocyanate (b1) satisfying the following conditions (1) to (4): (1) polyisocyanate (b1) is a product of reaction between polyether polyol and isocyanate compound; (2) polyether polyol includes 95 mol% or more of the hydroxyl group derived from difunctional polyether polyol; (3) isocyanate compound includes 90 mol% or more of the isocyanate group derived from aromatic diisocyanate compound; and (4) the ICI viscosity at 90°C of polyisocyanate (b1) is 600 [mPa-s] or more.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a solventless adhesive and a laminate using the same, which are suitable for lamination of various plastic films and metal-deposited films. Furthermore, the present invention relates to a package using the laminate, which is used for foods, medicines, cosmetics, detergents, miscellaneous goods, and the like.

In recent years, due to the tightening of laws and regulations and consideration of environmental conservation and safety, there is an increasing demand for solvent-free lamination adhesives used in packaging materials. In particular, refill packaging materials such as detergents and softeners are often composed of three or more layers of laminated films including a metallized film and a thick sealant film. and a non-solvent type adhesive that is compatible with heat sealing strength.
However, solvent-free adhesives are generally designed so that the molecular weight of the resin contained in them is small from the viewpoint of handling, and as a result, there is a problem that lamination strength and heat-sealing strength are lowered. On the other hand, if the above problem is solved by increasing the molecular weight of the resin, the viscosity increases and the appearance deteriorates. Therefore, conventional solvent-free adhesives have a trade-off with the performance described above, making it difficult to replace them from solvent-based adhesives.

In response to the above problem, Patent Document 1 describes a hot type solventless adhesive using a high molecular weight resin assuming high temperature coating, and by incorporating a nurate type or biuret type isocyanate It is described that the crosslink density is improved and the initial adhesive strength and heat resistance are improved.

JP 2012-67319 A

However, the solvent-free adhesive described in Patent Document 1 is designed to have a high crosslink density in order to compensate for heat resistance. Therefore, when hard substrates including metal vapor deposition films are bonded together to form a laminated film, the metal vapor deposition layer interface (for example, between nylon and aluminum vapor deposition PET in the structure of nylon (NY) / adhesive layer / aluminum vapor deposition PET, There is a problem that the adhesive strength between PET and aluminum-deposited PET in the structure of PET/adhesive layer/aluminum-deposited PET) is lowered. Furthermore, thick sealants are required to have heat resistance because they are heat-sealed at high temperatures. However, when a rigid skeleton is introduced to improve heat resistance, there is a problem that it tends to be a trade-off with the above-mentioned adhesive strength.
Accordingly, an object of the present invention is to provide a solvent-free adhesive that has excellent adhesive strength at the interface of the vapor-deposited metal layer, excellent heat-sealing strength (heat resistance), and excellent coatability. Another object of the present invention is to provide a laminate and a package which are excellent in adhesive strength, heat seal strength (heat resistance), and appearance at the interface of the vapor deposited metal layer.

As a result of earnest studies to solve the above problems, the inventors have found that the above problems can be solved by the following embodiments, and have completed the present invention.

A solventless adhesive according to one aspect of the present invention comprises a polyol compound (A) and a polyisocyanate compound (B), wherein the polyisocyanate compound (B) has the following (1) to (4): It is characterized by containing a first polyisocyanate (b1) that satisfies the above conditions.
(1) The polyisocyanate (b1) is a reaction product of a polyether polyol and an isocyanate compound.
(2) The polyether polyol contains a bifunctional polyether polyol, and the ratio of the total number of moles of hydroxyl groups contained in the bifunctional polyether polyol is based on the total number of moles of hydroxyl groups contained in the polyether polyol. is 95 mol % or more.
(3) The isocyanate compound contains an aromatic diisocyanate compound, and the ratio of the total number of moles of isocyanate groups contained in the aromatic diisocyanate compound is 90 moles based on the total number of moles of isocyanate groups contained in the isocyanate compound. % or more.
(4) The ICI viscosity at 90° C. of the polyisocyanate (b1) is 600 [mPa·s] or more.

In the solventless adhesive according to another aspect of the present invention, the polyisocyanate compound (B) further contains a second polyisocyanate (b2), and the mass of the polyisocyanate compound (B) is based on As, the second polyisocyanate (b2) is characterized by containing 5% by mass or more and 15% by mass or less (however, the second polyisocyanate (b2) excludes the first polyisocyanate (b1)) .

A solvent-free adhesive according to another aspect of the present invention is characterized in that the second polyisocyanate (b2) contains 4,4'-diphenylmethane diisocyanate.

A solventless adhesive according to another aspect of the present invention is characterized by further comprising a resin obtained by copolymerizing a (meth)acrylic acid ester and maleic anhydride.

A solventless adhesive according to another aspect of the present invention is a resin obtained by copolymerizing the (meth)acrylic acid ester and maleic anhydride, based on the mass of the polyisocyanate compound (B), .1% by mass or more and 2.0% by mass or less.

A solvent-free adhesive according to another aspect of the present invention is characterized by further comprising a filler having a pH value exceeding 7.0 as measured according to JIS K 5101.

A solventless adhesive according to another aspect of the present invention contains the filler in a range of 0.1% by mass or more and 2.0% by mass or less based on the mass of the polyisocyanate compound (B). characterized by

A solventless adhesive according to another aspect of the present invention is characterized in that the polyol compound (A) contains a polyester polyol.

A solventless adhesive according to another aspect of the present invention is characterized in that the polyester polyol is a reaction product of a hydroxyl group component and a carboxy group component, and satisfies all of the following (5) to (7). and
(5) The hydroxyl group component contains a diol, the carboxy group component contains a dicarboxylic acid, and the ratio of the total number of moles of hydroxyl groups and carboxy groups contained in the diol and the dicarboxylic acid is the hydroxyl group component and the carboxy group component. is 85 mol% or more based on the total number of moles of hydroxyl groups and carboxy groups contained in.
(6) The molar equivalent ratio (OH/COOH) between the hydroxyl group of the hydroxyl group component and the carboxy group of the carboxy group component is 1.1 or more and 1.5 or less.
(7) The carboxy group component contains 25 mol % or more and 60 mol % or less of the aromatic carboxy group component based on the total number of moles of the carboxy group component.

A laminate according to another aspect of the present invention is characterized in that an adhesive layer formed using the solventless adhesive is laminated between at least two sheet-like substrates.

In the laminate according to another aspect of the present invention, at least one of the at least two sheet-like substrates is a metal-deposited film, and the metal-deposited layer of the metal-deposited film and the adhesive layer are in contact with each other. It is characterized by

A package according to another aspect of the present invention is characterized by using the laminate described above.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a solvent-free adhesive that has excellent adhesive strength at the interface of a vapor-deposited metal layer, excellent heat seal strength (heat resistance), and excellent coatability. Further, according to the present invention, it is possible to provide a laminate and a package which are excellent in adhesive strength, heat seal strength (heat resistance), and appearance at the interface of the metal deposition layer.

[Solvent-free adhesive composition]
The solvent-free adhesive of the present invention comprises a polyol compound (A) and a polyisocyanate compound (B), and the polyisocyanate compound (B) satisfies the following (1) to (4). It is characterized by containing a polyisocyanate (b1).
(1) The polyisocyanate (b1) is a reaction product of a polyether polyol and an isocyanate compound.
(2) The polyether polyol contains a bifunctional polyether polyol, and the ratio of the total number of moles of hydroxyl groups contained in the bifunctional polyether polyol is based on the total number of moles of hydroxyl groups contained in the polyether polyol. is 95 mol % or more.
(3) The isocyanate compound contains an aromatic diisocyanate compound, and the ratio of the total number of moles of isocyanate groups contained in the aromatic diisocyanate compound is 90 moles based on the total number of moles of isocyanate groups contained in the isocyanate compound. % or more.
(4) The ICI viscosity at 90° C. of the polyisocyanate (b1) is 600 [mPa·s] or more.

The polyisocyanate (b1) is a highly flexible and viscous polyether urethane polyisocyanate having a high proportion of bifunctional polyether polyol. Therefore, high lamination strength can be exhibited even between hard substrates such as NY/aluminum-deposited PET and PET/aluminum-deposited PET. In addition, the polyisocyanate (b1) has an ICI viscosity of 600 [mPa s] or more at 90° C. and a high ratio of a rigid aromatic diisocyanate compound, so that it has high heat resistance and excellent heat sealing. Express strength. Furthermore, since the solventless adhesive of the present invention has the flexibility and rigidity described above, it is excellent in coatability and exhibits a good coating appearance.

More specifically, the polyisocyanate compound (B) used in the solventless adhesive of the present invention has the optimum balance of the following items (i) to (iii), so that the above excellent effects are achieved. It is presumed that it works.
(i) The stress relaxation ability ( flexible).
(ii) Polymer elasticity due to entanglement of polymer chains.
(iii) Interfacial cohesiveness (rigidity) due to the use of a high ratio of aromatic diisocyanate compounds, which are rigid skeletons with a low degree of freedom.

As a result, the solvent-free adhesive of the present invention and the laminate and package using the adhesive can be used as packaging materials for various applications such as foods, pharmaceuticals, cosmetics, detergents, miscellaneous goods, etc. In particular, it can be suitably used as a refill packaging material.
The present invention will be described in detail below.

<Polyol compound (A)>
The polyol compound (A) used in the present invention may be any compound having two or more hydroxyl groups, and can be selected from known polyols. As the polyol compound (A), one polyol may be used alone, or two or more polyols may be used in combination.
Examples of the polyols include polyester polyols, polycarbonate polyols, polycaprolactone polyols, polyether polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, and fluorine-based polyols.

These polyols may be those obtained by reacting some of the hydroxyl groups with diisocyanate to introduce urethane bonds (for example, polyether urethane polyols and polyester urethane polyols), and reacting some of the hydroxyl groups with acid anhydrides. A carboxyl group may also be introduced by the method.
Examples of the diisocyanate 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. mentioned.
Examples of the acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic ester anhydride. Trimellitic ester anhydrides include, for example, ester compounds obtained by subjecting an alkylene glycol or alkanetriol having 2 to 30 carbon atoms to an esterification reaction with trimellitic anhydride. Melitate, propylene glycol bisannehydrotrimellitate, and the like can be used.

The polyol compound (A) preferably contains polyether polyol or polyester polyol from the viewpoint of leveling property and adhesion performance to the substrate, and more preferably polyester polyol from the viewpoint of improving heat resistance and metal adhesion. includes.

(polyether polyol)
The polyether polyol may be a compound having two or more hydroxyl groups and two or more ether bonds in the molecule, and these polyether polyols may be used singly or in combination of two or more. good too.
Polyether polyols include, for example, polyalkylene glycols such as polyethylene glycol, polytrimethylene glycol, polypropylene glycol, polytetramethylene glycol, and polybutylene glycol; polyethylene glycol/polypropylene glycol block copolymers; propylene oxide/ethylene oxide random Polyether;
In addition, water, ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, sucrose and other low-molecular-weight polyols, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran and other oxirane compounds are addition-polymerized polyols. You may use it as an ether polyol.
Examples of the addition polymer include propylene glycol propylene oxide adducts, glycerin propylene oxide adducts, sorbitol-based propylene oxide adducts, and sucrose-based propylene oxide adducts.
The number average molecular weight of the polyether polyol is preferably 400 or more and 4,000 or less, more preferably 400 or more and 2,000 or less.

(polyester polyol)
Polyester polyol is, for example, a polyester polyol obtained by reacting a carboxyl group component and a hydroxyl group component; obtained polyester polyol;
The carboxy group component is not particularly limited as long as it is known, and monofunctional carboxylic acid or polyvalent carboxylic acid can be used. Examples of such carboxyl group components include monofunctional carboxylic acids having an aromatic ring such as benzoic acid, phenylacetic acid and 3-phenylpropionic acid; succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid. , maleic anhydride, non-cyclic aliphatic dicarboxylic acids such as fumaric acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, phthalic acid , 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid anhydrides or ester-forming derivatives of these aliphatic or aromatic dicarboxylic acids; p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid and ester-forming properties of these dihydroxycarboxylic acids. derivatives, polybasic acids such as dimer acid; Preferably, it is at least one selected from the group consisting of benzoic acid, adipic acid, sebacic acid, isophthalic acid and terephthalic acid.

Among them, from the viewpoint of adhesion performance and heat resistance, the carboxy group component preferably contains an aromatic carboxy group component. The aromatic carboxy group component includes a monofunctional aromatic carboxylic acid, a bifunctional aromatic dicarboxylic acid, and a trifunctional or higher aromatic polycarboxylic acid.
The aromatic carboxy group component is preferably 25 mol % or more and 60 mol % or less based on the total number of moles of the carboxy group components used in the synthesis of the polyester polyol. Particularly preferably, it is 35 mol % or more and 45 mol % or less. When it is 25 mol % or more, the difference between flexibility and rigidity becomes remarkable, a sea-island structure is formed, and adhesiveness and heat resistance are improved, which is preferable. When it is 60 mol % or less, the viscosity is reduced, and the appearance and pot life are improved, which is preferable.

The hydroxyl group component is not particularly limited as long as it is known, and examples thereof include diols and tri- or higher functional polyols.
Examples of the diol include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl 1,5-pentanediol, neopentyl glycol, 1,6 -aliphatic diols such as hexanediol, 3,3'-dimethylolheptane, 1,4-bis(hydroxymethyl)cyclohexane; ether glycols such as polytetramethylene ether glycol, polyoxyethylene glycol; said aliphatic diols and modified polyether diols obtained by ring-opening polymerization with various cyclic ether bond-containing compounds such as ethylene oxide and tetrahydrofuran; polycondensation of the above aliphatic diols with various lactones such as lactanoids and ε-caprolactone lactone-based polyester polyols obtained by reaction; and alkylene oxide adducts of bisphenol obtained by adding ethylene oxide or the like to bisphenols such as bisphenol A and bisphenol F; Preferably, it is at least one selected from the group consisting of ethylene glycol, diethylene glycol and neopentyl glycol.

Examples of trifunctional or higher polyols include aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol, and pentaerythritol; Modified polyether polyols obtained by ring-opening polymerization with various cyclic ether bond-containing compounds such as propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether; Lactone-based polyester polyols obtained by polycondensation reaction with various lactones; Preferred is trimethylolpropane.

From the viewpoint of imparting flexibility, the polyester polyol is preferably a polyester polyol using a bifunctional carboxy group component and/or a bifunctional hydroxyl group component such as dicarboxylic acid or diol. That is, it is preferably a reaction product of a hydroxyl group component containing a diol and a carboxy group component containing a dicarboxylic acid.
In addition, the ratio of the total number of moles of hydroxyl groups and carboxy groups contained in the diol and dicarboxylic acid is 85 mol% or more based on the total number of moles of hydroxyl groups and carboxy groups contained in the hydroxyl group component and the carboxy group component. preferable. Particularly preferably, it is 90 mol % or more. When it is 85 mol % or more, it is preferable because an excessive increase in the crosslink density is suppressed, a decrease in the degree of freedom of the polymer chain is prevented, and excellent flexibility is exhibited.

The ratio of the total number of moles of hydroxyl groups and carboxy groups contained in the above bifunctional raw materials (bifunctional carboxy group component and bifunctional hydroxyl group component) is determined by obtaining the number of moles of carboxy groups or hydroxyl groups contained in each raw material, and then After determining the total number of moles of carboxy groups and hydroxyl groups contained in all raw materials, the ratio of the total number of moles of carboxy groups or hydroxyl groups contained in the bifunctional raw materials may be calculated.
The number of moles of carboxy groups or hydroxyl groups contained in each raw material can be derived from the following formula.
[Number of moles of each raw material]
= [amount of each raw material charged (g)] × [number of functional groups of each raw material] / [molecular weight of each raw material]

The reaction equivalent ratio (OH/COOH) between the hydroxyl group of the hydroxyl group component and the carboxy group of the carboxy group component used for synthesizing the polyester polyol is preferably 1.1 or more and 1.5 or less. Especially preferably, it is 1.2 or more and 1.4 or less. When it is 1.1 or more, the cohesive force of the polyester polyol is increased, and the adhesive strength is more excellent, which is preferable. When it is 1.5 or less, the increase in viscosity after mixing with the polyisocyanate compound (B) is moderate, and deterioration in coatability over time can be suppressed, which is preferable.

<Polyisocyanate compound (B)>
The polyisocyanate compound (B) used in the present invention contains the first polyisocyanate (b1), which is a polyether urethane polyol that satisfies the above (1) to (4). By using polyether urethane as the main skeleton, the degree of freedom of the polymer chain is improved, and the cured adhesive layer has excellent flexibility. As a result, a laminate laminated between hard substrates can exhibit high adhesive strength that cannot be achieved with conventional solventless adhesives.

[Polyisocyanate (b1)]
Polyisocyanate (b1) in the present invention, the ratio of the total number of moles of hydroxyl groups contained in the bifunctional polyether polyol, based on the total number of moles of hydroxyl groups contained in the polyether polyol poly A reaction product of an ether polyol and an isocyanate compound in which the ratio of the total number of moles of isocyanate groups contained in the aromatic diisocyanate compound is 90 mol% or more based on the total number of moles of isocyanate groups contained in the isocyanate compound. and the ICI viscosity at 90° C. is 600 [mPa·s] or more.

(polyether polyol)
The polyether polyol contains a bifunctional polyether polyol, and the ratio of the total number of moles of hydroxyl groups contained in the bifunctional polyether polyol to the total number of moles of hydroxyl groups contained in the polyether polyol is 95 mol%. It is important that By containing a high ratio of 95 mol% or more of hydroxyl groups derived from bifunctional polyether polyol, the degree of freedom of the polymer chain increases, the flexibility of the adhesive layer after curing increases, and the adhesion between hard substrates increases. Adhesion strength can be expressed.
The bifunctional polyether polyol is not particularly limited, but, for example, among the polyether polyols described in the section of the polyol compound (A), bifunctional polyether polyols can be appropriately used. The bifunctional polyether polyol is preferably (poly)alkylene glycol such as dipropylene glycol, tripropylene glycol or polypropylene glycol, and more preferably (poly)propylene glycol.
From the viewpoint of flexibility and resin compatibility, the bifunctional polyether polyol preferably has a molecular weight of 400 to 2,000. A molecular weight of 400 or more is preferable because excellent cohesive force can be obtained during adhesion. When the molecular weight is 2,000 or less, the compatibility with the isocyanate compound described later increases, and the reactivity between the polyether polyol and the isocyanate compound improves, which is preferable.

The ratio of the total number of moles of hydroxyl groups contained in the bifunctional polyether polyol is obtained after obtaining the number of moles of hydroxyl groups contained in each polyether polyol and then obtaining the total number of moles of hydroxyl groups contained in all polyether polyols. , from which the ratio of the total number of moles of hydroxyl groups contained in the bifunctional polyether polyol can be obtained.
The number of moles of hydroxyl groups contained in each polyether polyol can be derived from the following formula.
[Number of moles of hydroxyl groups contained in each polyether polyol]
= ([Amount (g) of each polyether polyol charged] x [Hydroxyl value of each polyether polyol (mgKOH/g)])/([Number of functional groups of each polyether polyol] x 56100

The polyether polyol may be used in combination with a polyether polyol other than the bifunctional polyether polyol as long as the effects of the present invention are not impaired.

(isocyanate compound)
The isocyanate compound contains an aromatic diisocyanate compound, and the ratio of the total number of moles of isocyanate groups contained in the aromatic diisocyanate compound is 90 mol% or more based on the total number of moles of isocyanate groups contained in the isocyanate compound. It is important to have By using the aromatic diisocyanate compound at a high ratio of 90 mol% or more, not only the heat resistance is improved, but also the rigidity due to the aromatic ring and the flexibility of the polyether urethane chain described above improve the adhesive strength. .

Examples of aromatic diisocyanate compounds include diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, phenylene diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate.
Diphenylmethane diisocyanate is preferred as the aromatic diisocyanate compound.

The ratio of the total number of moles of isocyanate groups contained in the aromatic diisocyanate compound is obtained by obtaining the number of moles of isocyanate groups contained in each isocyanate compound for all isocyanate compounds used as isocyanate compounds, and then isocyanate contained in all isocyanate compounds. After obtaining the total number of moles of the groups, the ratio of the total number of moles of the isocyanate groups contained in the aromatic diisocyanate compound may be obtained.
The number of moles of isocyanate groups contained in each isocyanate compound can be derived from the following formula.
[Number of moles of each isocyanate compound]
= ([Amount (g) of each isocyanate compound charged] x [NCO% of each isocyanate compound])/([Number of functional groups of each isocyanate compound] x 42 x 100)

The isocyanate compound may be used in combination with an isocyanate compound other than the aromatic diisocyanate compound as long as the effect of the present invention is not impaired. Examples of isocyanate compounds that may be used in combination include tri- or more functional aromatic polyisocyanates and modified aromatic polyisocyanates. Examples of isocyanate compounds that may be used in combination include araliphatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and modified products thereof.

Examples of tri- or higher functional aromatic polyisocyanates include polymethylene polyphenyl polyisocyanates.
Modified aromatic polyisocyanates include, for example, allophanate-type modified products, isocyanurate-type modified products, biuret-type modified products, and adduct-type modified products. and a reaction product having an isocyanate group and a urethane bond. The polyol that forms the modified polyisocyanate is not particularly limited and can be selected from known polyols, such as polyester polyol, polyester urethane polyol, polycarbonate polyol, polycaprolactone polyol, polyether polyol, polyether Urethane polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, fluorine-based polyols.

Examples of araliphatic polyisocyanates include 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,3- or 1,4-bis( araliphatic diisocyanates such as 1-isocyanato-1-methylethyl)benzene or mixtures thereof;
Examples of aliphatic polyisocyanates include 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-diisocyanatomethylcaproate, lysine diisocyanate, dimer acid diisocyanate.
Examples of alicyclic polyisocyanates include 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(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, norbornene diisocyanate and other cycloaliphatic diisocyanates;

As for the modified polyisocyanate, the above-described modified aromatic polyisocyanate can be cited.

Moreover, it is important that the polyisocyanate (b1) has an ICI viscosity at 90° C. of 600 [mPa·s] or more. ICI viscosity means viscosity measured using an ICI viscometer (cone plate type). When the ICI viscosity at 90°C is 600 [mPa·s] or more, the cohesive force of the adhesive is increased, and excellent adhesive strength and heat resistance are exhibited. Furthermore, appearance defects such as orange peel and tunneling can be improved.
The ICI viscosity is preferably 800 [mPa·s] or more, more preferably 900 [mPa·s] or more, from the viewpoint of improving the cohesive force. From the viewpoint of handling properties during coating, the viscosity is preferably 1200 [mPa·s] or less, more preferably 1100 [mPa·s] or less.

[Polyisocyanate (b2)]
The polyisocyanate compound (B) may further contain a polyisocyanate (b2) other than the polyisocyanate (b1) for the purpose of imparting cohesive strength and reducing viscosity. By blending such a second polyisocyanate (b2) to impart cohesive force, a sea-island structure is formed in contrast to the flexibility of the polyisocyanate (b1), thereby improving adhesive strength and heat resistance. be able to. Moreover, appearance performance can be improved by reducing the viscosity of the polyisocyanate compound (B).

The blending amount of the polyisocyanate (b2) is preferably 5% by mass or more and 15% by mass or less based on the mass of the polyisocyanate compound (B). When it is 5% by mass or more, sufficient heat resistance can be imparted, which is preferable. When it is 15% by mass or less, the balance between cohesion and flexibility is improved, and both adhesive strength and heat resistance can be achieved, which is preferable.

Polyisocyanate (b2) preferably contains 4,4'-diphenylmethane diisocyanate. By using 4,4'-diphenylmethane diisocyanate, the density of the aromatic ring and the urethane bond can be increased, and the cohesive force can be efficiently imparted, which is preferable.

<Resin obtained by copolymerizing (meth)acrylic acid ester and maleic anhydride>
From the viewpoint of improving compatibility and improving adhesive strength, the solvent-free adhesive of the present invention preferably contains a resin obtained by copolymerizing (meth)acrylic acid ester and maleic anhydride.
The resin is not particularly limited as long as it is a copolymer of a known (meth)acrylic acid ester and maleic anhydride, and can be selected from conventionally known resins. Two or more kinds may be used in combination.

(Meth)acrylic acid esters represent methacrylic acid esters and acrylic acid esters, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, i-propyl methacrylate, butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, pentyl methacrylate, decyl methacrylate, heptyl methacrylate, cyclohexyl octylate methacrylate, and phenyl methacrylate. Among them, methyl methacrylate is preferable from the viewpoint of copolymerizability with maleic anhydride.

A method for copolymerizing (meth)acrylic acid ester and maleic anhydride includes a radical copolymerization method, which can be appropriately selected from solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and the like. The resin preferably contains 5 to 50% by mass, more preferably 30 Contains up to 50% by mass. It is preferable that the structural unit derived from maleic anhydride is 5% by mass or more, since the decrease in adhesive strength is suppressed when the laminate after lamination is stored for a long period of time. When it is 50% by mass or less, it is preferable because the copolymer of (meth)acrylic acid ester and maleic anhydride can be easily synthesized.

The acid value of the resin obtained by copolymerizing (meth)acrylic acid ester and maleic anhydride is preferably 250 mgKOH/g or more, more preferably 300 mgKOH/g or more, still more preferably 350 mgKOH/g or more. An acid value of 250 mgKOH/g is preferable because the cohesive force at the metal interface increases. The acid value of the resin obtained by copolymerizing (meth)acrylic acid ester and maleic anhydride is preferably 1000 mgKOH/g or less.

The weight average molecular weight (Mw) of the resin obtained by copolymerizing (meth)acrylic acid ester and maleic anhydride is preferably 1,000 to 5,000, more preferably 1,500 to 3,000. A weight-average molecular weight of 1,000 or more is preferable because the decrease in adhesive strength is suppressed when the laminate after lamination is stored for a long period of time. When it is 5,000 or less, the compatibility of the solventless adhesive is excellent and the coating appearance is excellent, which is preferable.

The weight average molecular weight in the present specification is a value converted to standard polystyrene using GPC (gel permeation chromatography) "Shodex GPCS System-21" manufactured by Showa Denko KK and using tetrahydrofuran as a solvent.
When the copolymer of (meth) acrylic acid ester and maleic anhydride contains a plurality of copolymers, the weight average molecular weight thereof can be determined from the weight average molecular weight of each copolymer and the mass ratio thereof.

The solventless adhesive of the present invention contains a resin obtained by copolymerizing a (meth)acrylic acid ester and maleic anhydride in an amount of 0.1% by mass or more based on the total mass of the polyisocyanate compound (B), It is preferably contained in the range of 2.0% by mass or less. When it is 0.1% by mass or more, the cohesive force at the metal interface is increased, and the adhesive strength and heat seal strength are excellent, which is preferable. When the amount is 2.0% by mass or less, the increase in viscosity after blending with the adhesive is moderate, and the appearance performance is improved, which is preferable.

<Filler with a pH value exceeding 7.0>
The solvent-free adhesive of the present invention preferably contains a filler having a pH value exceeding 7.0 as measured according to JIS K 5101.
By blending such a filler, the cohesive force of the adhesive after lamination is improved, and the appearance performance is improved, which is preferable. In particular, by coexisting with an acid component such as a resin obtained by copolymerizing the above-mentioned (meth)acrylic acid ester and maleic anhydride, the filler and the acid component electrically interact to disperse the filler. improve sexuality. As a result, sedimentation of the filler is suppressed, and poor appearance can be further reduced.

Fillers with a pH value exceeding 7.0 include, for example, aluminosilicates (manufactured by Mizusawa Chemical Industry Co., Ltd.: Shilton JC-20, etc.), magnesium oxide, silica, and the like. Aluminosilicates are preferred from the viewpoint of improving dispersibility and imparting cohesive force through interaction with acid components.
The average particle size of fillers with pH values above 7.0 is usually in the range of 1×10 ⁻⁵ to 0.2 mm, preferably in the range of 1×10 ⁻⁴ to 0.1 mm. When the average particle size is 0.2 mm or less, the coating film appearance after coating is excellent. When it is 1×10 ⁻⁵ mm or more, the fluidity of the adhesive is excellent and the coating appearance is excellent in transparency, which is preferable. The average particle diameter in the present specification is the average volume diameter and is a value determined by a laser light scattering method.

The solvent-free adhesive of the present invention contains a filler having a pH value exceeding 7.0 in a range of 0.1% by mass or more and 2.0% by mass or less based on the total mass of the polyisocyanate compound (B). It is preferable to include in When it is 0.1% by mass or more, the cohesive force of the adhesive after lamination is improved, and appearance defects such as orange peel and tunneling can be improved, which is preferable. When it is 2.0% by mass or less, the adhesive strength and heat resistance are maintained, which is preferable.

<Other ingredients>
In order to satisfy various performance requirements, the solventless adhesive of the present invention is a resin obtained by copolymerizing a polyol compound (A), a polyisocyanate compound (B), a (meth)acrylic acid ester and maleic anhydride, A component other than a filler having a pH value exceeding 7.0 as measured according to JIS K 5101 may be contained. Such other components may be blended with either the polyol compound (A) or the polyisocyanate compound (B), or may be blended when mixing the polyol compound (A) and the polyisocyanate compound (B). good too. Other components may be used singly or in combination of two or more.

(Silane coupling agent)
The solvent-free adhesive of the present invention can contain a silane coupling agent from the viewpoint of improving the adhesive strength to metal-based materials such as metal foils and metal deposition layers. Silane coupling agents include, for example, vinyltriethoxysilane, trialkoxysilane having a vinyl group such as vinyltriethoxysilane; 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltri trialkoxysilanes having an amino group such as methoxysilane; glycidyls such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane; a trialkoxysilane having a group;
The content of the silane coupling agent is preferably 0.1-5% by mass, more preferably 0.2-3% by mass, based on the total polyol compound. By setting it as the said range, since the adhesive strength with respect to metal foil can be improved, it is preferable.

(Phosphoric acid or phosphoric acid derivative)
The solvent-free adhesive of the present invention can contain phosphoric acid or a phosphoric acid derivative from the viewpoint of improving the adhesive strength to metal-based materials such as metal foils and metal deposition layers.
The phosphoric acid may have at least one free oxyacid, for example, hypophosphorous acid, phosphorous acid, orthophosphoric acid, phosphoric acids such as hypophosphoric acid; metaphosphoric acid, condensed phosphoric acids such as pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, ultraphosphoric acid; Examples of the phosphoric acid derivative include those obtained by partially esterifying the above phosphoric acid with alcohols while leaving at least one free oxyacid. Examples of the alcohols include aliphatic alcohols such as methanol, ethanol, ethylene glycol and glycerin; aromatic alcohols such as phenol, xylenol, hydroquinone, catechol and phloroglycinol.
The content of phosphoric acid or a derivative thereof is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and particularly preferably 0.05% by mass, based on the mass of the solventless adhesive. ~1% by mass.

(Leveling agent or antifoaming agent)
The solventless adhesive of the present invention may contain a leveling agent and/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-containing polydimethylsiloxane, polyether ester-modified hydroxyl-containing polydimethylsiloxane, and acrylic copolymers. , methacrylic copolymers, polyether-modified polymethylalkylsiloxanes, acrylic acid alkyl ester copolymers, methacrylic acid alkyl ester copolymers, and lecithin.
Antifoaming agents include, for example, silicone resins, silicone solutions, and copolymers of alkyl vinyl ethers, alkyl acrylates, and alkyl methacrylates.

(reaction accelerator)
The solventless adhesive of the present invention can contain a reaction accelerator to accelerate the curing reaction. Examples of reaction accelerators include metallic catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimaleate; 1,8-diaza-bicyclo(5,4,0)undecene-7,1 tertiary amines such as ,5-diazabicyclo(4,3,0)nonene-5,6-dibutylamino-1,8-diazabicyclo(5,4,0)undecene-7; reactivity such as triethanolamine tertiary amine;

(Additive)
The solvent-free adhesive of the present invention may contain various additives as long as the effects of the present invention are not impaired. Examples of additives include inorganic fillers such as alumina, mica, talc, aluminum flakes and glass flakes, layered inorganic compounds, stabilizers (antioxidants, heat stabilizers, ultraviolet absorbers, hydrolysis inhibitors, etc.), Antirust agents, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, fillers, crystal nucleating agents, and catalysts for adjusting the curing reaction.

<Laminate>
The laminate of the present invention is obtained by laminating an adhesive layer composed of the solventless adhesive described above between at least two sheet-like substrates. As an example, a non-solvent adhesive is applied to a first sheet-like substrate to form an adhesive layer, a second sheet-like substrate is superimposed on the adhesive layer, and an adhesive is applied between both sheet-like substrates. One obtained by curing the above-mentioned adhesive layer located thereon can be mentioned.

[Sheet-like base material]
The sheet-like substrate is not particularly limited, and examples thereof include conventionally known plastic films, papers, metal foils, etc., and the two sheet-like substrates may be of the same type or of different types.
As the plastic film, a film of thermoplastic resin or thermosetting resin can be used, preferably a film of thermoplastic resin. Examples of thermoplastic resins include polyolefins, polyesters, polyamides, polystyrenes, vinyl chloride resins, vinyl acetate resins, ABS resins, acrylic resins, acetal resins, polycarbonate resins, and cellulose plastics.
The sheet-like substrate may be provided with a barrier layer composed of a vapor deposited layer of metal or metal oxide, etc. Examples of the barrier layer include vapor deposited layers of aluminum, silica, alumina and the like.

The first sheet-like substrate is preferably a plastic film. Plastic films include those commonly used for packaging materials, polyester resin films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polylactic acid (PLA); polyethylene (PE), polypropylene Polyolefin resin film such as (PP); polystyrene resin film; polyamide resin film such as nylon 6, poly-p-xylylene adipamide (MXD6 nylon); polycarbonate resin film; polyacrylonitrile resin film; polyimide resin film multi-layers thereof (eg, nylon 6/MXD6/nylon 6, nylon 6/ethylene-vinyl alcohol copolymer/nylon 6) and mixtures thereof. Among them, those having mechanical strength and dimensional stability are preferable.
The plastic film preferably has a thickness of 5 μm or more and 50 μm or less, more preferably 10 μm or more and 30 μm or less.

When the second sheet-like substrate is the outermost layer of the laminate, the second sheet-like substrate is preferably a sealant substrate.
Examples of sealant base materials include polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE), acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, and copolymerization. Examples include polypropylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-(meth)acrylic acid copolymer, and ionomer.
The thickness of the sealant base material is not particularly limited, and is preferably 10 to 150 μm, more preferably 20 to 70 μm, in consideration of workability into packaging materials, heat sealability, and the like. In addition, by providing the sealant base material with unevenness having a height difference of about several μm, slipperiness and tearability of the packaging material can be imparted.
When the second sheet-like base material serves as an intermediate layer of the laminate, as the second sheet-like base material, the aforementioned plastic film, paper, metal foil, or the like can be preferably used.

The sheet-like substrate may have a printed layer on the substrate.
The printed layer contains letters, numbers, patterns, figures, symbols, patterns, etc. It is a layer that forms any desired printed pattern, and includes a solid printed layer. The printed layer can be formed using conventionally known pigments and dyes, and the method for forming the printed layer is not particularly limited.
Generally, the printing layer is formed using printing ink containing a colorant such as pigment or dye. The method of applying the printing ink is not particularly limited, and the printing ink can be applied by methods such as gravure coating, flexo coating, roll coating, bar coating, die coating, curtain coating, spin coating, and inkjet. . A printed layer can be formed by leaving this as it is, or if necessary, blowing air, heating, drying under reduced pressure, irradiating with ultraviolet rays, or the like.
The print layer preferably has a thickness of 0.1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less, still more preferably 1 μm or more and 3 μm or less.

Examples of the method for producing the laminate include a conventionally known method. For example, a non-solvent adhesive is applied to one side of one sheet-like substrate using a laminator to form an uncured adhesive layer. After that, the coated surface and the other sheet-like substrate are laminated together, and then the adhesive layer is cured at normal temperature or under heat. The coating amount of the solventless adhesive is preferably 1.0-5.0 g/m ² , more preferably 1.5-4.5 g/m ² . The thickness of the laminate is preferably 10 μm or more.

Examples of the structure of the laminate of the present invention are shown below, but the present invention is not limited thereto. When the laminate has a plurality of adhesive layers, at least one of the adhesive layers may be an adhesive layer formed from the solventless adhesive of the present invention. Also, hereinafter, transparent vapor deposition means a vapor deposition layer of silica or alumina.
biaxially oriented polypropylene (OPP)/printing layer/adhesive layer/non-oriented polypropylene (CPP),
OPP/printing layer/adhesive layer/AL deposition CPP,
OPP/printing layer/adhesive layer/PE,
printing layer/OPP/adhesive layer/CPP,
NY/printing layer/adhesive layer/PE,
Print layer/NY/adhesive layer/CPP
NY/printing layer/adhesive layer/CPP,
PET/printing layer/adhesive layer/CPP,
printing layer/PET/adhesive layer/CPP,
PET/printing layer/adhesive layer/NY/adhesive layer/CPP,
PET/printing layer/adhesive layer/NY/adhesive layer/PE,
transparent deposition PET/printing layer/adhesive layer/NY/adhesive layer/CPP,
PET/printing layer/adhesive layer/AL deposition PET/adhesive layer/PE,
NY/printing layer/adhesive layer/AL deposition PET/adhesive layer/PE,
PET/printing layer/adhesive layer/AL deposition PET/adhesive layer/NY/adhesive layer/PE,
PET/printing layer/adhesive layer/AL/adhesive layer/CPP,
PET/printing layer/adhesive layer/AL/adhesive layer/PE,
PET/printing layer/adhesive layer/NY/adhesive layer/AL/adhesive layer/CPP,
PET/printing layer/adhesive layer/AL/adhesive layer/NY/adhesive layer/CPP

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. "Parts" and "%" in Examples and Comparative Examples mean "mass parts" and "mass%" unless otherwise specified.

[Measurement method of weight average molecular weight (Mw) and number average molecular weight (Mn)]
The weight average molecular weight and number average molecular weight were measured using GPC (gel permeation chromatography) "Shodex GPCS System-21" manufactured by Showa Denko. GPC is liquid chromatography for separating and quantifying a substance dissolved in a solvent based on the difference in molecular size. The solvent was tetrahydrofuran, and the molecular weight was determined in terms of polystyrene.

[Method for measuring hydroxyl value (OHV)]
About 1 g of a sample was accurately weighed into a common-stoppered Erlenmeyer flask, and dissolved by adding 100 mL of a toluene/ethanol (volume ratio: toluene/ethanol=2/1) mixed solution. Exactly 5 mL of an acetylating agent (a solution of 25 g of acetic anhydride dissolved in pyridine to a volume of 100 mL) was further added and stirred for about 1 hour. To this, phenolphthalein test solution is added as an indicator and maintained for 30 seconds. After that, the solution was titrated with a 0.1N alcoholic potassium hydroxide solution until it turned pink. The hydroxyl value was obtained by the following (formula 2). The hydroxyl value was taken as the numerical value of the dry state of the resin.
(Formula 2) hydroxyl value (mgKOH/g) = [{(ba) × F × 28.25} / S] / (non-volatile content / 100) + D
S: Sample collection amount (g)
a: consumption of 0.1N alcoholic potassium hydroxide solution (mL)
b: Consumption of 0.1N alcoholic potassium hydroxide solution in blank experiment (mL)
F: Potency of 0.1N alcoholic potassium hydroxide solution D: Acid value (mgKOH/g)

[Method for measuring NCO content (% by mass)]
About 1 g of a sample was weighed into a 200 mL Erlenmeyer flask, and 10 mL of a 0.5N di-n-butylamine toluene solution and 10 mL of toluene were added and dissolved. Next, 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 pale red. The NCO content (% by mass) was determined by the following (Equation 3).
(Formula 3): NCO (mass%) = {(ba) x 4.202 x F x 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

[Method for measuring ICI viscosity]
The viscosity at 90° C. was measured using a cone plate viscometer “CV-1S” manufactured by Toa Kogyo Co., Ltd. The displayed value when the numerical value stabilized was taken as the ICI viscosity.

<Production of polyol compound (A)>
(Synthesis of polyether polyol (A-1))
520.1 parts of polypropylene glycol having a number average molecular weight of 2,000, 218.4 parts of polypropylene glycol having a number average molecular weight of 400, and 16.6 parts of dipropylene glycol and 45.0 parts of tolylene diisocyanate were charged and heated at 80° C. to 90° C. for 3 hours while stirring under a stream of nitrogen gas to conduct a urethanization reaction, thereby introducing a polyether into which urethane bonds were introduced. A polyol (A-1) was obtained.

(Synthesis of polyether polyols (A-2 to A-5))
Polyether polyols (A-2 to A-5) in which urethane bonds were introduced by conducting a urethanization reaction in the same manner as in (A-1), except that the raw materials were changed to the formulations (parts by mass) shown in Table 1. got

Polyether polyols (A-1 to A-5) are shown in Table 1. The numerical values in Table 1 are parts by mass.

(Synthesis of polyester polyol (A-6))
322.7 parts of adipic acid, 226.7 parts of isophthalic acid, 74.7 parts of ethylene glycol, and 375 parts of neopentyl glycol were added to a reaction vessel equipped with a stirrer, temperature system, reflux condenser, dropping tank and nitrogen gas inlet tube. 9 parts were charged, and the temperature was raised to 240° C. while stirring under a nitrogen stream. After the reaction was continued until the acid value became 5 or less, the pressure was gradually reduced, the reaction was continued at 1 mmHg, excess alcohol was removed, and polyester polyol (A-6) was obtained.

(Synthesis of polyester polyol (A-8))
321.1 parts of adipic acid, 176.4 parts of isophthalic acid, 49.2 parts of benzoic acid and 74.3 parts of ethylene glycol were placed in a reaction vessel equipped with a stirrer, temperature system, reflux condenser, dropping tank and nitrogen gas inlet tube. and 374.0 parts of neopentyl glycol were charged, and the temperature was raised to 240° C. while stirring under a nitrogen stream. After the reaction was continued until the acid value became 5 or less, the pressure was gradually reduced to continue the reaction at 1 mmHg to remove excess alcohol. Thereafter, 5.0 parts of ethylene glycol bisanehydrotrimellitate was added to the resulting resin and reacted at 120° C. for 1 hour to react with an acid anhydride to introduce a carboxyl group polyester polyol (A-8 ).

(Synthesis of polyester polyols (A-7, A-9 to A-16))
Polyester polyols (A-7, A-9 to A-16) were obtained by conducting an esterification reaction in the same manner as in (A-6) except that the raw materials were changed to the formulation (parts by mass) shown in Table 1. rice field.

Polyester polyols (A-6 to A-16) are shown in Table 2. The numerical values in Table 2 are parts by mass.

<Production of polyisocyanate (b1)>
(Synthesis of polyisocyanate (b1-1))
103.9 parts of polypropylene glycol having a number average molecular weight of 400, 518.3 parts of polypropylene glycol having a number average molecular weight of 2,000, and 13.1 parts of dipropylene glycol, 18.7 parts of tripropylene glycol, and 346.0 parts of a mixture of 2,4-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate (mass ratio: 50:50) were charged, and a stream of nitrogen gas was introduced. By performing a urethanization reaction by heating at 80 ° C. to 90 ° C. for 3 hours while stirring at the bottom, a poly with an isocyanate group content of 5.4% by mass and an ICI viscosity at 90 ° C. An isocyanate (b1-1) was obtained.

(Synthesis of polyisocyanate (b1-2 to b1-10))
Polyisocyanates (b1-2 to b1-10) were obtained by conducting the urethanization reaction in the same manner as in (b1-1), except that the raw materials were changed to the formulations (parts by mass) shown in Table 1.

(Synthesis of polyisocyanate (b1-11))
599.4 parts of polyester polyol (A-7), 2,4-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate were placed in a reaction vessel equipped with a stirrer, temperature system, reflux condenser, dropping tank and nitrogen gas inlet tube. 400.6 parts of the mixture is charged and heated at 80 ° C. to 90 ° C. for 3 hours while stirring under a nitrogen gas stream to perform a urethanization reaction, so that the isocyanate group content is 10.1% by mass and 90 ° C. A polyisocyanate (b1-11) having an ICI viscosity of 1000 [mPa/s] was obtained.

Table 3 shows the polyisocyanates (b1-1 to b1-11). The numerical values in Table 3 are parts by mass.

Abbreviations in Table 3 are shown below.
4,4'-MDI: 4,4'-diphenylmethane diisocyanate 2,4'-MDI: 2,4'-diphenylmethane diisocyanate HDI Biuret: biuret-type polyisocyanate, trimer of 1,6-hexamethylene diisocyanate

<Production of Resin by Copolymerizing (Meth)Acrylic Acid Ester and Maleic Anhydride>
(Synthesis of Resin-1)
200 parts of toluene was introduced into a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction tube, and the temperature was raised to 110° C. while stirring while introducing nitrogen gas. Next, 90 parts of methyl methacrylate, 70 parts of butyl acrylate, 40 parts of maleic anhydride, and 50 parts of toluene are added to dropping tank 1, and a solution obtained by dissolving 9 parts of benzoyl peroxide in 50 parts of toluene is added to dropping tank 2, While maintaining the temperature in the reaction vessel at 110° C. over 2 hours, they were added dropwise with stirring. After completion of the reaction, the reaction is cooled to room temperature, the polymer is precipitated with a large amount of methanol, filtered and dried at 120°C for 6 hours. Resin-1 was obtained by copolymerizing with an acid.

(Synthesis of Resin-2)
200 parts of toluene was introduced into a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction tube, and the temperature was raised to 110° C. while stirring while introducing nitrogen gas. Next, 90 parts of methyl methacrylate, 50 parts of butyl acrylate, 80 parts of maleic anhydride, and 50 parts of toluene are added to dropping tank 1, and a solution obtained by dissolving 9 parts of benzoyl peroxide in 50 parts of toluene is added to dropping tank 2, While maintaining the temperature in the reaction vessel at 110° C. over 2 hours, they were added dropwise with stirring. After the reaction was completed, the reaction was cooled to room temperature, the polymer was precipitated with a large amount of methanol, filtered and dried at 120°C for 6 hours. Resin-2 was obtained by copolymerizing with an acid.

(Synthesis of Resin-3)
200 parts of toluene was introduced into a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction tube, and the temperature was raised to 110° C. while stirring while introducing nitrogen gas. Next, 80 parts of methyl methacrylate, 50 parts of butyl acrylate, 100 parts of maleic anhydride, and 50 parts of toluene are charged in dropping tank 1, and 9 parts of benzoyl peroxide dissolved in 50 parts of toluene are charged in dropping tank 2, While maintaining the temperature in the reaction vessel at 110° C. over 2 hours, they were added dropwise with stirring. After the reaction was completed, the reaction was cooled to room temperature, the polymer was precipitated with a large amount of methanol, filtered, and dried at 120°C for 6 hours. Resin-3 was obtained by copolymerizing with an acid.

<Production of non-solvent adhesive>
[Examples 1 to 37, Comparative Examples 1 to 4] Solventless adhesives 1 to 41
Polyol compound (A), polyisocyanate compound (B), and other components were mixed according to the formulations shown in Table 4 to obtain solventless adhesives 1-41.

<Evaluation of non-solvent adhesive>
The following evaluations were carried out on the obtained solvent-free adhesives. The results are shown in Tables 4 and 5.

[Production of laminate]
Printing ink (Rio Alpha R631 white, manufactured by Toyo Ink Co., Ltd.) was mixed with ethyl acetate/IPA mixed solvent (mass ratio 70/30) so that the viscosity was 16 seconds (25° C., Zahn cup No. 3). diluted to A gravure proofing machine equipped with a solid plate with a plate depth of 35 μm is used to print the diluted printing ink on a 15 μm-thick nylon film ("EMBLEM ON-RT" manufactured by Unitika, hereinafter referred to as NY) at a printing speed of 50 m/min. and dried at 50°C. The thickness of the printed layer was within the range of 0.5 to 1 μm.
Next, using a laminator in a room temperature environment, the ink surface of the printed matter obtained above and a 12 μm-thick aluminum-deposited polyethylene terephthalate film ("Dialuster H27" manufactured by Reiko Co., Ltd., hereinafter referred to as VM-PET) were separated. The aluminum-deposited surface was bonded using the obtained solvent-free adhesive. The lamination speed was 150 [m/min] and the coating amount was 2.0 [g/m ² ]. After bonding, the adhesive was hardened to some extent by keeping the temperature at 40° C. for 6 hours.
Then, using a laminator in a room temperature environment, a linear low-density polyethylene film (“TUX-FCD” manufactured by Mitsui Tohcello Co., Ltd., hereinafter referred to as LLDPE) with a thickness of 100 μm and a surface corona discharge treatment, and the obtained above The obtained solvent-free adhesive was applied to the PET surface of the laminated film having the structure of "NY/printing layer/adhesive layer/VM-PET" at a speed of 150 [m/min] and a coating amount of 2.0 [ g/m ² ], and then kept at 40° C. for 3 days to completely harden the adhesive. A certain laminate was obtained.

[Adhesion strength]
The obtained laminate was cut into a test piece having a width of 15 mm and a length of 300 mm. Based on JIS K6854, using an Instron type tensile tester, tensile at a peel speed of 300 mm / min in an environment of temperature 20 ° C. and relative humidity 65%, T-type peel strength between NY and VM-PET [N/15 mm] was measured. The measurement was performed 5 times, and the average value was used for evaluation according to the following criteria.
A: 4.5 [N / 15 mm] or more (very good)
B: 3.5 [N/15 mm] or more and less than 4.5 [N/15 mm] (good)
C: 2.5 [N/15 mm] or more and less than 3.5 [N/15 mm] (usable)
D: less than 2.5 [N / 15 mm] (cannot be used)

[Heat seal peeling test]
The obtained laminate was cut into a test piece having a width of 15 mm and a length of 300 mm. After that, based on JIS K6854, using an Instron type tensile tester, it was pulled at a peel speed of 300 mm / min in an environment of 20 ° C. and 65% relative humidity, and film breakage or breakage of the heat-sealed part occurred. The test was run until the tensile strength dropped. Next, the samples after the test were observed and evaluated according to the following criteria depending on the form. The measurement was performed 5 times, and the most common form was adopted.
A: The laminate film was broken, but the heat-sealed part was completely maintained (very good)
B: No breakage of the laminate film occurred, only the LLDPE film was broken (good)
C: Laminate film breakage did not occur, and VM-PET/LLDPE in the heat-sealed portion began to peel, and the LLDPE film alone broke (usable).
D: The film did not break at all, and only the VM-PET/LLDPE at the heat-sealed portion was peeled off (cannot be used).

[Coatability, appearance performance]
The obtained laminate was rewound, and the number of meters at which all appearance defects such as orange peel, tunneling, air bubbles, and adhesive blurring disappeared between NY-VMPET and between VM-PET/LLDPE was measured and evaluated according to the following criteria. did The smaller the meter number, the shorter the time from the start of lamination to the disappearance of the poor appearance, and the better the coatability.
A: Defective appearance disappeared at a meter number of 0 m or more and less than 3 m (very good)
B: Defective appearance disappeared at meters of 3 m or more and less than 10 m (good)
C: Defective appearance disappeared at meters of 10 m or more and less than 15 m (usable)
D: The appearance defect disappeared at a meter number of 15 m or more, or the appearance defect did not disappear (unusable)

Abbreviations and details in Tables 4 and 5 are shown below.
Lupranate M-20S: manufactured by BASF, a mixture of polymeric diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate (mass ratio 60:40)
Mixture of 2,4′-MDI and 4,4′-MDI: Mixture of 2,4-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate (mass ratio 50:50)
HDI biuret: Biuret-type polyisocyanate, trimer of 1,6-hexamethylene diisocyanate Siltone JC-20: Mizusawa Chemical Industry Co., Ltd., aluminosilicate (pH: 11.0), average particle size 2.0 × 10 ^-3mm
Kyowamag MF30: manufactured by Kyowa Chemical Industry Co., Ltd., magnesium oxide filler (pH: 10.3), average particle size 5.4 × 10 ^-4 mm
Mizukasil P-707: manufactured by Mizusawa Chemical Industry Co., Ltd., silica filler (pH: 9.5), average particle size 4.0 × 10 ^-3 mm

From the evaluation results, the solvent-free adhesive of the present invention was excellent in adhesive strength when using a hard substrate including a metal deposition interface such as NY-VMPET. In addition, it showed good heat seal peelability test results and was excellent in heat resistance. Furthermore, the poor appearance disappeared immediately after starting the lamination, and the coatability was excellent.
In particular, Example 3 containing 10% by mass of the polyisocyanate (b2) in the polyisocyanate compound (B), Example 35 containing 5% by mass of the polyisocyanate (b2), and an implementation not containing the polyisocyanate (b2) Compared to Example 36, which contains 20% by mass of the second polyisocyanate (b2), the balance between flexibility and rigidity was good, and the adhesive strength and heat seal peel test were good.
Example 3 containing 4,4′-diphenylmethane diisocyanate in polyisocyanate (b2) has higher rigidity than Example 15 containing aliphatic HDI biuret in polyisocyanate (b2), and the heat seal peel test is good. Met.
Example 3 containing 0.45% by mass of a resin obtained by copolymerizing a (meth)acrylic acid ester and maleic anhydride based on the total mass of the polyisocyanate compound (B) contains 2.5% by mass of the resin. It has better compatibility with the resin than Example 7 containing 2% by mass, and has excellent coatability and appearance performance, and has higher metal adhesion and excellent adhesive strength than Examples 12 and 13 that do not contain the resin. was
Example 3 containing 0.9% by mass of a filler having a pH value of more than 7.0 measured in accordance with JIS K 5101, based on the total mass of the polyisocyanate compound (B), contains 2 The adhesion to the substrate of the resin is higher than in Example 10 containing .2% by mass, the adhesive strength and the heat seal peel test are good, and the cohesive force after lamination is higher than in Examples 11 and 13 that do not contain the filler Due to the high viscosity, there were few air bubbles, and the coating properties and appearance performance were excellent.
Example 3 containing polyester polyol in polyol compound (A) has higher metal adhesion and rigidity than Examples 30, 31, 32, 33, and 34 containing polyether polyol in polyol compound (A). , excellent in adhesive strength and heat seal peel test.
Example 3 containing a polyester polyol synthesized so that the total number of moles of a bifunctional hydroxyl group component and a bifunctional carboxy group component is 100 mol% in the polyol compound (A) uses a trifunctional raw material. As compared with Examples 18 and 19, the degree of freedom of the polymer chain was higher and the stress relaxation property was higher, so that the adhesive strength was excellent.
Example 3 containing a polyester polyol synthesized at a molar equivalent ratio (OH/COOH) of 1.3 between a bifunctional hydroxyl group component and a bifunctional carboxy group component in the polyol compound (A) is Since the viscosity was lower than that of Example 22 containing the polyester polyol synthesized in 1.1, the base material leveling property was high, and the coatability and appearance performance were excellent. In addition, the adhesion to the substrate and the rigidity were higher than in Example 23 containing the polyester polyol synthesized at a ratio of 1.5, and the adhesive strength and the heat seal peel test were good.
The polyol compound (A) is synthesized from a bifunctional hydroxyl group component and a bifunctional carboxy group component, and the bifunctional carboxy group component is aromatic based on the total number of moles of the bifunctional carboxy group component Example 3, which contains 40 mol % or less of the aromatic carboxy group component, has higher rigidity than Example 20, which contains 31 mol % or less of the aromatic carboxy group component, and is good in the heat seal peel test. Moreover, since the viscosity was lower than that of Example 21 containing 51 mol % or less of the aromatic carboxyl group component, the base material leveling property was high, and the coatability and appearance performance were excellent.

Claims (12)

Containing a polyol compound (A) and a polyisocyanate compound (B),
A solvent-free adhesive in which the polyisocyanate compound (B) contains a first polyisocyanate (b1) that satisfies the following (1) to (4).
(1) The polyisocyanate (b1) is a reaction product of a polyether polyol and an isocyanate compound.
(2) The polyether polyol contains a bifunctional polyether polyol, and the ratio of the total number of moles of hydroxyl groups contained in the bifunctional polyether polyol is based on the total number of moles of hydroxyl groups contained in the polyether polyol. is 95 mol % or more.
(3) The isocyanate compound contains an aromatic diisocyanate compound, and the ratio of the total number of moles of isocyanate groups contained in the aromatic diisocyanate compound is 90 moles based on the total number of moles of isocyanate groups contained in the isocyanate compound. % or more.
(4) The ICI viscosity at 90° C. of the polyisocyanate (b1) is 600 [mPa·s] or more. The polyisocyanate compound (B) further contains a second polyisocyanate (b2), and the second polyisocyanate (b2) is 5% by mass or more based on the mass of the polyisocyanate compound (B), 2. The solventless adhesive according to claim 1, containing 15% by mass or less (however, the second polyisocyanate (b2) excludes the first polyisocyanate (b1)). 3. The solventless adhesive of claim 2, wherein said second polyisocyanate (b2) comprises 4,4'-diphenylmethane diisocyanate. 4. The solventless adhesive composition according to any one of claims 1 to 3, further comprising a resin obtained by copolymerizing a (meth)acrylic acid ester and maleic anhydride. The resin obtained by copolymerizing the (meth)acrylic acid ester and maleic anhydride is contained in the range of 0.1% by mass or more and 2.0% by mass or less based on the mass of the polyisocyanate compound (B). 5. The solventless adhesive composition of claim 4. The solvent-free adhesive according to any one of claims 1 to 5, further comprising a filler having a pH value exceeding 7.0 as measured according to JIS K 5101. The solventless adhesive according to claim 6, wherein the filler is contained in the range of 0.1% by mass or more and 2.0% by mass or less based on the mass of the polyisocyanate compound (B). The solventless adhesive according to any one of claims 1 to 7, wherein the polyol compound (A) comprises a polyester polyol. The solventless adhesive according to any one of claims 1 to 8, wherein the polyester polyol is a reaction product of a hydroxyl group component and a carboxy group component and satisfies all of the following (5) to (7).
(5) The hydroxyl group component contains a diol, the carboxy group component contains a dicarboxylic acid, and the ratio of the total number of moles of hydroxyl groups and carboxy groups contained in the diol and the dicarboxylic acid is the hydroxyl group component and the carboxy group component. is 85 mol% or more based on the total number of moles of hydroxyl groups and carboxy groups contained in.
(6) The molar equivalent ratio (OH/COOH) between the hydroxyl group of the hydroxyl group component and the carboxy group of the carboxy group component is 1.1 or more and 1.5 or less.
(7) The carboxy group component contains 25 mol % or more and 65 mol % or less of the aromatic carboxy group component based on the total number of moles of the carboxy group component. A laminate in which an adhesive layer formed using the solventless adhesive according to any one of claims 1 to 9 is laminated between at least two sheet-like substrates. 11. The laminate according to claim 10, wherein at least one of the at least two sheet-like substrates is a metal-deposited film, and the metal-deposited layer of the metal-deposited film is in contact with the adhesive layer. A package using the laminate according to claim 10 or 11.