JPH08183943A - Adhesive composition for dry laminate and dry laminate processing method using the same - Google Patents

Abstract

PURPOSE: To obtain an adhesive for dry laminate providing excellent adhesiveness and heat resistance in producing a composite film by laminating various plastic films, metal-deposited films or aluminum foils, etc. CONSTITUTION: This adhesive composition for dry laminate contains a polyol component, a monool component, as necessary, and a polyisocyanate component in an equivalent ratio of (hydroxyl group/isocyanate group) of (1.0/1.1)-(1.0/10.0). In the adhesive composition, a hydroxycarboxylic acid having a number-average molecular weight of 200-5000, an acid value of 20-350 and a hydroxyl value of 20-350 as a part of the polyol component and/or monool component, is contained in an amount of an acid value derived from the hydroxycarboxylic acid in the acid value of a solid part of the adhesive composition so as to be 1-20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry laminating adhesive for obtaining a composite laminate film and a dry laminating method using the same, and more specifically, laminating various plastic films, metal vapor deposition films, aluminum foils and the like. The present invention relates to an adhesive for dry lamination, which imparts an excellent adhesive property and resistance when producing a composite film, and a dry laminating method using the same.

[0002]

2. Description of the Related Art Composite films obtained by laminating various plastic films in multiple layers are widely used as soft packaging materials for foods and the like. There is a dry laminating method in which it is pasted with an agent.

The composite film obtained by this dry laminating method is used under harsh conditions such as packaging bags for heavy articles such as bottles and tubes, hot water boiling and retort treatment packaging bags for cooking and sterilization. Often used in fields requiring resistance underneath, adhesion between films (lamination strength), bag-making strength (seal strength)
It must have sufficient water resistance and oil resistance (suitability for boil and retort) at high temperatures.

Since the laminating strength, sealing strength and boil / retort suitability are greatly influenced by the performance of the dry laminating adhesive used, an adhesive having as strong adhesiveness and heat resistance as possible between the films. Is used.

Further, as a high-performance composite film, a composite film laminated with a metal vapor deposition film is used as a packaging material for applications where a gas barrier property for impermeable to moisture or the like is required. A composite film laminated with aluminum foil is used as a packaging material for high-retort treatment that is immersed in pressurized hot water, and the adhesive that bonds them has good adhesiveness to the metal surface as well. I have to

Therefore, generally, as an adhesive used in dry lamination, a polyester polyol obtained by reacting a diol compound with a dicarboxylic acid or by ring-opening polymerization of a lactone, an alkylene oxide addition of a diol compound, or the like is used. It is known that the obtained polyether polyol and the like and an isocyanate compound are combined, but these adhesives have sufficient adhesive strength and boiling in bonding of various plastic films and metal vapor deposition films or aluminum foils.・
Cannot get retort suitability.

In particular, even if there is no problem immediately after lamination, in the case of a metal vapor deposition film, if it is exposed to a humid atmosphere for a long time, the sealing strength and the laminating strength decrease,
Further, in the case of aluminum foil, there is a problem that the sealing strength and the laminating strength after the retort treatment are reduced.

Therefore, in order to solve these problems,
Several adhesive compositions have been proposed, for example: a polybasic acid having at least two acid anhydride groups in the molecule in the polyol component of the adhesive composition consisting of a polyol component and a polyisocyanate component. Adhesive composition for composite laminate film obtained by adding an anhydride (for example, Japanese Examined Patent Publication No. 3-46034),-Polyester and ethylenically unsaturated carboxylic acid or acid anhydride thereof in the presence of a radical generator. An adhesive for dry lamination (for example, Japanese Examined Patent Publication No. 5-80515) obtained by blending a polyisocyanate compound with a modified polyester composition obtained by reaction is known.

[0009]

However, the former of the above-mentioned adhesives cannot be added in a large amount because the polybasic acid anhydride has a poor solubility in the polyether polyol adhesive, so that the laminating strength and boil retort suitability are not improved. However, the latter method has a problem that the process for obtaining an adhesive for dry lamination is complicated and it is difficult to obtain a stable product.

[0010]

The present inventors have found the present invention as a result of intensive studies to solve the above problems.

That is, according to the present invention, the polyol component and, if necessary, the monool component and the polyisocyanate component have a hydroxyl group / isocyanate group equivalent ratio of 1.0 /
In the adhesive composition for dry lamination, which is contained in a ratio of 1.1 to 1.0 / 10.0, as a part of the polyol component and / or the monool component, a number average molecular weight of 200 to 5000 and an acid value of A hydroxycarboxylic acid having a hydroxy value of 20 to 350 and a hydroxy value of 20 to 350 is contained in an amount such that the acid value derived from the hydroxycarboxylic acid in the solid content of the adhesive composition is 1 to 20. And an adhesive composition for dry lamination.

In a preferred embodiment thereof, a dry laminate containing, as the polyol component other than the hydroxycarboxylic acid, at least one of a polyether polyol compound, a polyester polyol compound, a polyether ester polyol compound and a polyurethane polyol. The present invention relates to an adhesive composition.

The present invention also relates to a dry laminating method using these dry laminating adhesives.

[0014]

FUNCTION AND EXAMPLES The present invention will be described in more detail below.

1. Components Constituting Adhesive The adhesive for dry lamination of the present invention is cured by a reaction of a specific hydroxycarboxylic acid, other polyol component and optionally a monool component, and a polyisocyanate component to develop adhesiveness. The details of each component are as follows.

1) Hydroxycarboxylic Acid First, as the hydroxycarboxylic acid used in the present invention, a. Hydroxycarboxylic acid (A type hydroxycarboxylic acid) obtained by reacting a polyol monocarboxylic acid compound and / or a polyol polycarboxylic acid compound with a lactone compound or a polyisocyanate compound b. Hydroxycarboxylic acid (B type hydroxycarboxylic acid) obtained by reacting a polycarboxylic acid anhydride and a polyol compound in the presence of excess hydroxyl groups. C. Hydroxycarboxylic acids (C-type hydroxycarboxylic acids) obtained by reacting a polyol compound and a polycarboxylic acid compound in the presence of excess hydroxyl groups can be roughly classified into three types.

A type hydroxycarboxylic acid A dimethylolpropionic acid or the like is used as the polyol monocarboxylic acid, which is one of the reaction components of the A type hydroxycarboxylic acid, and a polyhydroxy polyvalent carboxylic acid compound such as tartaric acid is used as the polyol polycarboxylic acid. Is mentioned.

Further, dicarboxylic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, and phthalic anhydride, polycarboxylic acid monoanhydrides such as trimellitic anhydride, and glycerin, trimethylolpropane, pentaerythritol, etc. A polyol compound is reacted, or tetracarboxylic dianhydrides such as pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and 2,3,6,7-naphthalenetetracarboxylic dianhydride are added to ethylene glycol and propylene glycol. , Diethylene glycol, butylene glycol, neopentyl glycol,
A glycol compound such as 1,6-hexanediol, a compound obtained by reacting the polyol compound or a mixture thereof can also be used.

The other reaction component, the lactone compound, is preferably a 4-membered to 7-membered ring, and may be a derivative having a substituent such as an alkyl group or an alkoxyl group. Specifically, β-propiolactone, α, α-dimethyl-β-propiolactone,
δ-valerolactone, β-ethyl-δ-valerolactone, ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ-methyl-
ε-caprolactone, β, γ-dimethyl-ε-caprolactone, 3,3,5-trimethyl-ε-caprolactone and the like can be mentioned, and they can be used alone or in combination.

As the polyisocyanate compound, any of an aromatic diisocyanate compound, an alicyclic diisocyanate compound, an aliphatic diisocyanate compound and an araliphatic diisocyanate compound can be used, and dimers and trimers derived from these monomers can be used. ,
Burettes, allophanates, and adducts with trimethylolpropane, glycerin, polyetherester polyols, polyurethane polyols and other polyols can also be used.

Here, the aromatic diisocyanate compound is tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, the alicyclic diisocyanate compound is 1,4-cyclohexane diisocyanate, isophorone diisocyanate, and the aliphatic diisocyanate compound is hexahexadiene. Methylene diisocyanate, 2,2,4- or 2,4
Examples of 4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and araliphatic diisocyanate compounds include α, α, α ′, α′-tetramethylxylylene diisocyanate.

B-Type Hydroxycarboxylic Acid As the polycarboxylic acid anhydride which is one of the reaction components of the B-type hydroxycarboxylic acid, the above-mentioned polycarboxylic acid monoanhydride and polycarboxylic acid dianhydride can be mentioned.

As the other reaction component, the polyol compound, a polyether polyol compound, a polyester polyol compound, a polyether ester polyol compound, or the like can be used.

As the polyether polyol compound, one kind or two or more kinds of oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran are polymerized with water, the glycol compound, the polyol compound and the like as an initiator. The polyether polyol compound thus obtained can be mentioned.

As the polyester polyol compound, for example, the glycol compound, the polyol compound or a mixture thereof and a dicarboxylic acid compound such as adipic acid, azelaic acid, sebacic acid, terephthalic acid or isophthalic acid, or a dialkyl ester thereof or a compound thereof is used. Examples thereof include a polyester polyol obtained by reacting with a mixture, the glycol component, and a polyester polyol obtained by polymerizing the lactone compound as an initiator such as the polyol component.

Further, as the polyether ester polyol compound, there may be mentioned a polyether ester polyol obtained by polymerizing the lactone compound using a polyether polyol as an initiator.

The ring-opening reaction of the acid anhydride group with a hydroxyl group, the reaction of adding a lactone to the hydroxyl group, and the reaction of the hydroxyl group with an isocyanate group to obtain A and B type hydroxycarboxylic acids are carried out by known methods. You can

C-type hydroxycarboxylic acid A hydroxycarboxylic acid obtained by reacting the glycol compound, the polyol compound and the dicarboxylic acid compound can be mentioned.

Among the hydroxycarboxylic acids obtained by the above reaction components and reaction method, in the present invention, the number average molecular weight is 200 to 5,000, preferably 400 to 4,000,
An acid value in the range of 20 to 350, preferably 40 to 250, and a hydroxyl value in the range of 20 to 350, preferably 40 to 300 is used.

If the number average molecular weight of the hydroxycarboxylic acid is less than the above range or the acid value exceeds the above range, the compatibility with other polyol components and polyisocyanate components is lowered. On the other hand, when the number average molecular weight of the hydroxycarboxylic acid exceeds the above range, or the acid value is less than the above range, the metal vapor deposition film of the obtained adhesive composition, the adhesiveness to an aluminum foil and the boiling retort suitability are descend.

Further, when the hydroxyl value of the hydroxycarboxylic acid is less than the above range, the adhesiveness of the obtained adhesive composition to the metal vapor deposition film and aluminum foil is lowered, while when it exceeds the above range, the adhesive is The cured coating film of becomes hard and the adhesiveness to the plastic film decreases.

2) Other Polyol Components and Monool Components Next, other polyol components used in the present invention (hereinafter, referred to as other polyol components in order to distinguish from the above-mentioned hydroxycarboxylic acid) are usually used. Examples thereof include polyether polyol compounds, polyester polyol compounds, polyether ester polyol compounds and polyurethane polyol compounds that can be used in the adhesive for dry lamination.

Here, the polyether polyol compound is obtained by polymerizing the hydroxylane compound with a low molecular weight polyol component as an initiator, and the polyester polyol compound is the glycols or a mixture thereof and the dicarboxylic acid. Examples thereof include those obtained by reacting with a compound or a dialkyl ester thereof or a mixture thereof.

Examples of the polyether ester polyol compound include those obtained by reacting the above dicarboxylic acid compound or dialkyl ester thereof or a mixture thereof with the above polyether polyol compound.

Further, the polyurethane polyol compound is a polyol compound having a urethane bond in the molecule, and at least one polyol compound selected from the polyester polyol compound, the polyether polyol compound and the polyester ether polyol compound and the above-mentioned polyol compound. Examples thereof include those obtained by reacting an organic polyisocyanate compound at a hydroxyl group / isocyanate group equivalent ratio of 1.0 or more, preferably 1.2 or more.

The number of functional groups of the other polyol component used in the present invention is usually 2 to 6, preferably 2 to 4. The number average molecular weight is usually 500 to 100.
000, preferably 1,000 to 30,000.

As another monool component other than the optional component, a monoalcohol having about 1 to 18 carbon atoms can be used. For example, methanol, ethanol, propanol, butanol, hexanol, octanol, lauryl alcohol, stearyl alcohol and the like can be mentioned.

3) Polyisocyanate Component Next, the polyisocyanate component used in the present invention is
Any of the aromatic diisocyanate compounds, alicyclic diisocyanate compounds, aliphatic diisocyanate compounds, and araliphatic diisocyanate compounds can be used,
Furthermore, the dimer, trimer, burette, allophanate, trimethylolpropane, glycerin,
Adducts with polyols such as polyetherester polyol and polyurethane polyol can also be used.

2. Adhesive composition In the dry laminate adhesive composition comprising the above polyol component and optionally a monool component, and a polyisocyanate component, the content of the hydroxycarboxylic acid is the acid value of the solid content of the adhesive composition. The amount of the acid value derived from the hydroxycarboxylic acid is 1 to 20. If the content of hydroxycarboxylic acid is less than this range, the adhesiveness to the metal vapor deposition film or aluminum foil will be reduced, while if it is too large, the adhesive film will be too hard and the adhesiveness to the metal vapor deposition film or aluminum foil will be too. Occurs.

The content ratio of the polyol component and optionally the monool component (including hydroxycarboxylic acid) and the polyisocyanate component is such that the equivalent ratio of hydroxyl group / isocyanate group in the adhesive composition is 1.0 / 1. 1 ~
1.0 / 10.0, more preferably 1.0 / 1.5-
The range is 1.0 / 3.0. If the ratio of the number of functional groups is smaller than this range, the adhesiveness and laminating suitability are deteriorated due to poor curing, while if it is large, the appearance is deteriorated due to decarboxylation, and the coating film becomes too hard and the metal vapor deposition film or aluminum still remains. Adhesion to the foil is reduced.

Further, the adhesive composition of the present invention comprises, if necessary, known adhesion improvers (silane coupling agents, etc.) and various additives (antioxidants, ultraviolet absorbers, hydrolysis inhibitors, thickeners). , Plasticizers, pigments, fillers, etc.).

3. Method of Using Adhesive Next, a method of using the adhesive composition of the present invention will be described.

The adhesive composition of the present invention is used in either solvent type or solventless type.

As the solvent capable of dissolving the adhesive composition of the present invention, aromatic solvents such as benzene, toluene and xylene, which are well known as organic solvents, methanol, ethanol, isopropanol, n-butanol and the like are usually used. Alcohol solvents, acetone, methyl ethyl ketone, methyl isobutyl ketone and other ketone solvents, ethyl acetate, butyl acetate, propyl acetate and other ester solvents, tetrahydrofuran and other ethers, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc. Examples thereof include polyhydric alcohol derivatives, which can be used alone or in combination.

As the plastic film that can be used as the base film of the laminated processed product, various plastic films such as ordinary polyolefin, modified polyolefin, polyester, nylon, polystyrene, and the like, and metal vapor-deposited films thereof can be used. The adhesive of the invention exerts an excellent effect on a metal vapor deposition film.

As the sealant film, a film of polyethylene, polypropylene or the like, or a metal vapor deposition film of these can be used.

Examples of the laminated product include a laminate of the base film and the sealant film, a laminate of the base film and the sealant film with an aluminum foil interposed therebetween, or a composite laminate film of two or more layers. Can be given.

As a method of laminating using the adhesive composition of the present invention, an adhesive composition obtained by mixing each of the above-mentioned components immediately before use on the surface of a base film on which printing ink is printed if necessary. The thing is applied to the film surface with a laminator, the film is further stuck to the applied surface, and the composition is cured at room temperature or under heating.

The coating amount of the adhesive composition is usually 1 to 10 g / m ² (as solid content) for the solvent type and about 0.5 to 6 g / m ^{2 for the} solventless type.

The laminated product obtained by the above method is a dry laminated product having excellent adhesive, transparency and resistance.

Examples will be specifically described below, but the present invention is not limited thereto. Unless otherwise specified, parts and% in Examples and the like represent parts by weight and% by weight.

<Production of Polyol Component> Synthesis Example 1 (Polyol A1) In a flask equipped with a stirrer, a thermometer, and a nitrogen gas introducing tube,
Isophthalic acid 166 parts Neopentyl glycol 105
Parts, 60 parts of ethylene glycol, and 15 parts of trimethylolpropane, and while introducing N ² gas, 160 to 22
The esterification reaction was carried out at 0 ° C. After confirming that the predetermined amount of water was distilled, 188 parts of azelaic acid was added to 220 to 23.
Perform the esterification reaction at 0 ° C and gradually reduce the pressure to 22
After the condensation reaction at 0 ~ 230 ℃ for 90 minutes, 1-2mmH
The condensation reaction was carried out for 6 hours under the conditions of g and 220 to 230 ° C. Then, 534 parts of ethyl acetate was added and stirred for 30 minutes to obtain a polyol A1 having a number average molecular weight of 6000, a hydroxyl value of 15.3 and a solid content of 50%.

Synthesis Example 2 (Polyol A2) In the same apparatus as in Synthesis Example 1, 167 parts of isophthalic acid, 66 parts of neopentyl glycol, and 37 parts of ethylene glycol were added.
Parts, 40 parts of 1,6-hexamethylene glycol,
The esterification reaction was performed at 160 to 220 ° C. while introducing N ² gas. After confirming that a predetermined amount of water was distilled, 57 parts of adipic acid was added to carry out an esterification reaction at 220 to 230 ° C., and a condensation reaction was performed at 220 to 230 ° C. for 90 minutes while gradually reducing pressure, then 1 to 2 mmHg, 220-230 ° C
The condensation reaction was carried out for 6 hours under the conditions. Further, add 48 parts of isophorone diisocyanate and 427 parts of ethyl acetate,
After reacting at 70 ° C. for 10 hours, 12 parts of 1,6-hexamethylene glycol was added and the urethanization reaction was continued for 10 hours.
This was carried out for a time to obtain a polyol A2 having a number average molecular weight of 7,200, a hydroxyl value of 7.8 and a solid content of 50%.

Synthesis Example 3 (Polyol A3) 150 parts of polypropylene glycol having a number average molecular weight of 2000, 315 parts of polypropylene glycol having a number average molecular weight of 400, 155 parts of tolylene diisocyanate and 80 parts of ethyl acetate were placed in the same apparatus as in Synthesis Example 1. Put, 70 ℃
At room temperature for 3 hours, then trimethylolpropane 1
After adding 8.4 parts, the mixture was further reacted at 70 ° C. for 5 hours. Then, 133 parts of ethyl acetate was added and stirred for 30 minutes to obtain a polyol A3 having a number average molecular weight of 5900, a hydroxyl value of 23.4 and a solid content of 75%.

Synthesis Example 4 (Polyol A4) 750 parts of polypropylene triol having a number average molecular weight of 3000 and 1000 number average molecular weight were placed in the same apparatus as in Synthesis Example 1.
250 parts of polypropylene triol was added and stirred at room temperature for 30 minutes to obtain polyol A4 having a hydroxyl value of 84.2.

Synthesis Example 5 (Hydroxycarboxylic acid B
1) A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with dimethylolpropionic acid 134.
Parts and 100 parts of ε-caprolactone were added, and the mixture was heated to 180 ° C. while introducing N ² gas to uniformly dissolve dimethylolpropionic acid. Next, tetrabutyl titanate 0.
A dispersion of 04 parts in 200 parts of ε-caprolactone was added dropwise to the reaction solution with stirring and reacted at 180 ° C. for 2 hours to give a number average molecular weight of 430, a hydroxyl value of 259 and an acid value of 130.
Of hydroxycarboxylic acid B1 was obtained.

Synthesis Example 6 (Hydroxycarboxylic acid B
2) Dimethylolpropionic acid 1 was placed in the same device as in Synthesis Example 5.
18 parts and 100 parts of ε-caprolactone were added, and the mixture was heated to 180 ° C. while introducing N ² gas to dissolve dimethylolpropionic acid uniformly. Next, 0.32 parts of tetrabutyl titanate dispersed in 2522 parts of ε-caprolactone was added dropwise to the reaction solution with stirring and reacted at 180 ° C. for 2 hours to give a number average molecular weight of 2700, a hydroxyl value of 41, and an acid value of 20.
To obtain hydroxycarboxylic acid B2.

Synthesis Example 7 (Hydroxycarboxylic acid B
3) In a device similar to that used in Synthesis Example 5, neopentyl glycol /
A polyester diol having a number average molecular weight of 500, obtained from a 1,4-butanediol = 1/1 molar ratio and an isophthalic acid / adipic acid = 1/1 molar ratio, and 500 parts of trimellitic anhydride were added at 85 ° C. Was reacted for 3 hours to obtain a hydroxycarboxylic acid B3 having a number average molecular weight of about 700, a hydroxyl value of 81, and an acid value of 162.

Synthesis Example 8 (Hydroxycarboxylic acid B
4) In a device similar to that of Synthesis Example 5, neopentyl glycol /
1000 parts of polyester diol having a number average molecular weight of 1000 obtained from 1,4-butanediol = 1/1 molar ratio and isophthalic acid / adipic acid = 1/1 molar ratio and 148 parts of phthalic anhydride were added, and at 85 ° C. The reaction was carried out for 3 hours to obtain hydroxycarboxylic acid B4 having a number average molecular weight of 1150, a hydroxyl value of 49 and an acid value of 49.

Synthesis Example 9 (Hydroxycarboxylic acid B
5) Using a device similar to that used in Synthesis Example 5, neopentyl glycol /
1000 parts of polyester diol having a number average molecular weight of 500 and 218 parts of pyromellitic dianhydride, obtained from 1,4-butanediol = 1/1 molar ratio and isophthalic acid / adipic acid = 1/1 molar ratio, were added to 85 ° C. And reacted for 3 hours to obtain hydroxycarboxylic acid B5 having a number average molecular weight of about 1200, a hydroxyl value of 92 and an acid value of 92.

Synthesis Example 10 (Hydroxycarboxylic acid B
6) 800 parts of polypropylene glycol (number average molecular weight 400) and 218 parts of pyromellitic dianhydride were put in the same apparatus as in Synthesis Example 5, and reacted at 120 ° C. for 3 hours while introducing N ² gas, and the number average molecular weight was about 1,000, hydroxyl value 11
A hydroxycarboxylic acid B6 having an acid value of 0 and an acid value of 110 was obtained.

Synthesis Example 11 (Hydroxycarboxylic acid B
7) Using a device similar to that used in Synthesis Example 5, neopentyl glycol /
1000 parts of a polyester diol having a number average molecular weight of 2000 obtained from a 1,4-butanediol = 1/1 molar ratio and an isophthalic acid / adipic acid = 1/1 molar ratio, 200 parts of dimethylolpropionic acid and 180 parts of tolylene diisocyanate are added. The resulting mixture was reacted at 70 ° C. for 10 hours to obtain hydroxycarboxylic acid B7 having a number average molecular weight of about 1440, a hydroxyl value of 78 and an acid value of 61.

Synthesis Example 12 (Hydroxycarboxylic acid B
8) Trimethylolpropane 67 was added to the same device as in Synthesis Example 5.
Part, 156 parts of neopentyl glycol, 135 parts of 1,4-butanediol, 219 parts of adipic acid and 249 parts of isophthalic acid were heated to 180 ° C. and reacted until the acid value became 0.01 or less, then 80 The mixture was cooled to ° C, 96 parts of trimellitic anhydride was added, and the mixture was reacted at 80 ° C for 6 hours to obtain hydroxycarboxylic acid B8 having a number average molecular weight of 1800, a hydroxyl value of 61, and an acid value of 61.

Synthesis Example 13 (Hydroxycarboxylic acid B
9) Dimethylolpropionic acid 1 was placed in the same apparatus as in Synthesis Example 5.
Put 34 parts, 100 parts of ε-caprolactone, 180 ° C
The mixture was heated to dimethylolpropionic acid to uniformly dissolve it. Next, 0.03 parts of tetrabutyl titanate dispersed in 14 parts of ε-caprolactone was added dropwise to the stirred reaction solution and reacted at 180 ° C. for 2 hours to give a number average molecular weight of 25.
A hydroxycarboxylic acid B9 having 0, a hydroxyl value of 450 and an acid value of 225 was obtained.

Synthesis Example 14 (Hydroxycarboxylic acid B
10) Dimethylolpropionic acid 1 was placed in the same device as in Synthesis Example 5.
34 parts and 100 parts of ε-caprolactone were added and heated to 180 ° C. to uniformly dissolve dimethylolpropionic acid.
Next, 0.6 parts of tetrabutyl titanate dispersed in 5600 parts of ε-caprolactone was added dropwise to the stirred reaction solution, and the mixture was reacted at 180 ° C. for 2 hours to give a number average molecular weight of 580.
A hydroxycarboxylic acid B10 having a hydroxyl value of 0, a hydroxyl value of 19, and an acid value of 9.6 was obtained.

<Synthesis of Polyisocyanate Component> Synthesis Example 15 (Polyisocyanate C1) A trimethylolpropane adduct of isophorone diisocyanate (Takenate D140) was placed in the same apparatus as in Synthesis Example 1.
N, Takeda Pharmaceutical Co., Ltd. 500 parts, xylylene diisocyanate trimethylolpropane adduct (Takenate D110N, Takeda Pharmaceutical Co., Ltd.) 500 parts, and stirred at room temperature for 30 minutes to obtain polyisocyanate C1. Obtained.

Synthesis Example 16 (Polyisocyanate C
2) In a device similar to Synthesis Example 1, 55 parts of polypropylene glycol having a number average molecular weight of about 200, 21.5 parts of polypropylene glycol having a number average molecular weight of 400, 18.5 parts of trimethylolpropane, 175 parts of diphenylmethane diisocyanate and 90 parts of ethyl acetate. 1 part at 70 ℃
The reaction was carried out for 0 hours to obtain polyisocyanate C2.

Synthesis Example 17 (Polyisocyanate C
3) In the same device as in Synthesis Example 1, 100 parts of polyoxypropylenetriol having a number average molecular weight of 250 and 95 number average molecular weight were used.
228 parts of polyoxypropylene glycol of 0 and 336 parts of diphenylmethane diisocyanate were added and reacted at 70 ° C. for 8 hours to obtain polyisocyanate C3.

Adhesive Compositions and Evaluation Tests Examples 1 to 9 and Comparative Examples 1 to 7 The polyol component, hydroxycarboxylic acid component and polyisocyanate component obtained in Synthesis Examples 1 to 17 were mixed in the compounding amounts shown in Table 1. Then, the adhesive compositions of Examples 1 to 9 and Comparative Examples 1 to 7 were prepared. Further, a composite film was produced using each of these adhesive compositions, and their laminating strength and retort suitability were evaluated, and the evaluation results are shown in Table 2. The adhesive of Comparative Example 5 was observed as a white turbid matter, and thus was not evaluated.

Production of Composite Film Examples 1 to 9 and Comparative Examples 1 to 4, 6 and 7 were applied to an OPP film with a dry laminator, and then VM-CPP was used.
The films were laminated to produce a composite film of configuration 1.
In addition, Examples 1 to 5, 8, 9 and Comparative Examples 1 to 5 were applied to a PET film with a dry laminator, aluminum (AL) foil was laminated, and the same adhesive was applied, followed by CPP. The films were laminated to produce a composite film of configuration 2.

Structure 1: OPP / VM-CPP Structure 2: PET / AL foil / CPP Here, the OPP film is a stretched polypropylene film (Pyrene P2161, 30μ manufactured by Toyobo Co., Ltd.),
PET film is polyester film (Polyester E-5102, 12μ manufactured by Toyobo Co., Ltd.), VM-
CPP film is an aluminum-deposited unstretched polypropylene film (ML film CP-WA, 25μ manufactured by Toyo Cellophane Co., Ltd.), and CPP film is an unstretched polypropylene film (trefan NO ZK-93K, 60μ manufactured by Toray Gosei Co., Ltd.). Say.

Evaluation Method and Evaluation Criteria 1) Lamination Strength Each composite film was cut into a width of 15 mm, and was manufactured by Yasuda Seiki Co., Ltd.
The T-type peel strength was measured at a peeling speed of 300 mm / min using a peeling tester. The peel strength between the Al foil and the CPP of the composite film of constitution 2 was measured.

The peel strength is a measured value of g / 15 mm.

2) Retort Suitability The film of the composition 2 was aged at 40 ° C. for 3 days, then made into a bag of 10 cm × 14 cm, filled with vinegar inside and sealed, and heated under hot water at 135 ° C. A retort treatment was performed by immersing it in the inside for 20 minutes. The retort suitability was evaluated from the change in the appearance of the sample.

A: No change in appearance was observed. B: Some pinhole-shaped lamella float is observed. C: A large number of pinhole-shaped lamella floats are recognized. D: Streak-shaped lami is floated all over the surface.

The performance level aimed at by the present invention is B
That is all.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

As described above in the examples, by incorporating the polyhydroxycarboxylic acid specified in the present invention into the adhesive composition, the adhesive strength to VM-CPP, A
When the L foil is used, the retort suitability is remarkably improved, and the adhesive of the present invention is superior to the conventional adhesives, particularly in the composite film application using VM-CPP and AL foil. is there.

Claims (3)

[Claims] 1. A polyol component and, if necessary, a monool component and a polyisocyanate component in a hydroxyl group / isocyanate group equivalent ratio of 1.0 / 1.1 to 1.0 /.
In the adhesive composition for dry lamination, which is contained at a ratio of 10.0, the number average molecular weight of 200 to 100 is part of the polyol component and / or the monool component.
Containing a hydroxycarboxylic acid having an acid value of 5,000, an acid value of 20 to 350, and a hydroxyl value of 20 to 350 in an amount such that the acid value derived from the hydroxycarboxylic acid in the solid content of the adhesive composition is 1 to 20. An adhesive composition for dry laminating, comprising: 2. A polyether polyol compound as the polyol component other than the hydroxycarboxylic acid,
The adhesive composition for dry lamination according to claim 1, which contains at least one selected from the group consisting of a polyester polyol compound, a polyether ester polyol compound and a polyurethane polyol. 3. A dry laminating process comprising printing a printing ink on a plastic film if necessary, applying the adhesive composition for dry laminating according to claim 1 or 2, and then laminating the plastic film. Method.