JPH0794654B2 - Adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to adhesiveness and transparency used for producing a composite laminate film by laminating various plastic films, metal foils, metal vapor deposition films, papers and the like. TECHNICAL FIELD The present invention relates to a two-component curable adhesive composition having excellent properties and durability.

[Prior Art] A multi-layer composite film obtained by laminating a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, and polyamide with a metal foil, a metal vapor deposition film, etc. in two or three layers is used for food, medicine, cosmetics and household products. Widely used as a flexible packaging material.

Conventionally, an organic solvent solution type adhesive of phthalate ester type polyester or phthalic acid type polyester polyurethane has been used for adhering the above-mentioned plastic film to the metal foil or the metal vapor deposition film.

Further, in recent years, a solventless laminator has been developed, and this solventless laminator is widely used for laminating multi-layer composite films.

[Problems to be Solved by the Invention] As a solventless laminator for use in laminating a multilayer composite film, machines of several companies have been developed and are already in practical use. These solventless laminators are basically a direct roll coating method with three scroll rolls, and the adhesive is made into a thin film with a thickness of 1 to 5 μm and applied to the film to be adhered. Laminating with other adherend film at high speed. Therefore, the viscosity range of the adhesive is remarkably limited, and a high-viscosity, high-molecular-weight polyester type adhesive is unsuitable for practical use.

Polyether-based polyurethane polyisocyanate adhesives have been used as general-purpose adhesives, but this type of adhesive has not been sufficiently satisfactory in adhesion to metal foils and metal deposition films. .

The present inventors have conducted extensive studies with the object of eliminating the above-mentioned drawbacks of the prior art, and as a result, have a polyol having a carboxyl group bonded to the main chain via an ester bond or a carboxyl bonded to the main chain via an ester bond. A two-component curable adhesive containing a polyurethane polyol obtained by copolymerizing a polyol having a group has low viscosity and good workability, and has excellent adhesiveness to a metal foil and a metal vapor deposition film, At the same time, the present invention was reached by finding that an adhesive layer having transparency and flexibility is formed.

[Means for Solving the Problems] That is, the present invention comprises a polyol or a polyurethane polyol and a polyurethane polyisocyanate.
In the liquid curable adhesive composition, as the polyol, a polyol having a carboxyl group obtained by reacting a polyol having a trifunctional or higher functional hydroxyl group with a polycarboxylic acid so that at least two hydroxyl groups remain, and the polyurethane polyol An adhesive composition comprising a polyurethane polyol obtained by copolymerizing a carboxyl group-containing polyol obtained by reacting a polycarboxylic acid having a trifunctional or higher hydroxyl group with at least two hydroxyl groups. And adhesive compositions in which the composition is essentially free of organic solvents.

Hereinafter, the present invention will be described in detail. The polyol used in the present invention and having a carboxyl group bonded to the main chain through an ester bond, which is one of the components characterizing the present invention, is a trifunctional or higher functional hydroxyl group. The polyol is obtained by reacting various polycarboxylic acids, preferably polycarboxylic acids having an acid anhydride group in the molecule, so that at least two hydroxyl groups of the polyol remain.

Preferable polyols include, for example, glycerin, diglycerin, polyglycerin, erythritol, pentaerythritol, arabite, sorbit, sorbitan, mannitol, mannitan, trimethylolpropane, and the like.
Or higher alcohol or ethylene oxide, propylene oxide using these alcohols as an initiator,
Polyether polyols obtained by polymerizing alkylene oxides such as butylene oxide, polyester polyols having trihydric or higher hydroxyl groups consisting of these polyhydric alcohols or polyether polyols and dicarboxylic acids, and the above alkylenes starting from organic polyamines. Examples thereof include oxide polymers and polyester polyols having a trivalent or higher hydroxyl group, which are obtained from the polymers and dicarboxylic acids.

Among these polyols used in the present invention, particularly preferable are polyether triol and polycaprolactone triol having a molecular weight of about 90 to 4000.

As the polycarboxylic acid to be reacted with the above-mentioned polyol, any polycarboxylic acid having two or more carboxyl groups can be used. Specifically, for example, oxalic acid, malonic acid, succinic acid, and glutaric acid. Acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, methylmaleic acid,
Methyl fumaric acid, itaconic acid, citraconic acid, mesaconic acid, acetylenic acid, malic acid, methyl malic acid, citric acid, isocitric acid, tartaric acid, phthalic acid, isophthalic acid,
Examples thereof include terephthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, and their alkyl esters, acid halides, acid anhydrides, and the like. Among the above-mentioned polycarboxylic acids used in the present invention, acid is most preferable. An acid anhydride having an anhydride group.

The above-mentioned reaction of the polyol and the polycarboxylic acid is preferably carried out in a ratio such that the obtained carboxylic acid-modified polyol becomes a diol, for example, in a ratio of 1 mol of dicarboxylic acid anhydride to 1 mol of triol. The reaction between the polyol and the polycarboxylic acid, particularly the acid anhydride of the polycarboxylic acid is extremely easy and may be performed according to a conventional method.

A polyurethane polyol obtained by copolymerizing a polyol having a carboxyl group bonded to the main chain through an ester bond used in the present invention is reacted with a polyol and an organic polyisocyanate compound according to a conventional method, and if necessary, a small amount of It can be easily obtained by using a chain extender in combination.

In the present invention, as the polyol used in combination with the above-mentioned polyol having a carboxyl group, conventionally known polyols that can be used in ordinary polyurethane production can be used alone or in combination of two or more kinds.

As such a conventionally known polyol, for example, the terminal group is a hydroxyl group, and the molecular weight is 300 to 4000.
Polyethylene adipate, polyethylene propylene adipate, polyethylene butylene adipate, polydiethylene adipate, polybutylene adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, polytetramethylene ether glycol, poly-ε- Examples thereof include caprolactone all, polyhexamethylene adipate, carbonate polyol, polyethylene glycol, polypropylene glycol and the like.

The polyurethane polyisocyanate used in the present invention is
The polyols may be premixed and reacted with the polyisocyanates, or the polyols may each be independently reacted with the organic polyisocyanates and then mixed. At the time of mixing, an isocyanate adduct, an isocyanate multimer and the like can be simultaneously mixed.

The organic polyisocyanate used in the present invention,
It is a compound having at least two isocyanate groups in an aliphatic or aromatic compound, and has been widely used conventionally as a raw material for synthesizing polyurethane resins.

Any of these known organic polyisocyanates are useful in the present invention. Particularly preferable organic polyisocyanates are as follows.

Tolylene diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2, 4-diisocyanate-diphenyl ether, mesitylene diisocyanate, 4,4'-
Methylenebis (phenylisocyanate), durylylene diisocyanate, 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, 4,4'-diisocyanate dibenzyl, 1,4-tetramethylene diisocyanate, 1,6-tetramethylene diisocyanate , 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylene diisocyanate, 4,4-methylene bis (cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate and the like.

The chain extender that may be used in the present invention includes ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, water and the like.

In the adhesive composition of the present invention, the polyurethane polyol solution and the polyurethane polyisocyanate or polyisocyanate curing agent are used in an equivalent ratio of NCO to active hydrogen groups of 1: 1.
It is used by blending so that it falls within the range of preferably from -10 to 1.2-5.

[Advantageous Effects of the Invention] The adhesive composition of the present invention can obtain an adhesive force with a metal surface by the carboxyl group bonded to the main chain through an ester bond and, at the same time, can be appropriately softened by preparing a polyurethane resin composition of its body. It is believed that the formation of an adhesive film with properties protects the fragile metal deposition / film gap.

Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 A flask equipped with a thermometer, a stirrer and a distillation tube was charged with 1000 parts by weight of an ethylene oxide adduct of trimethylolpropane (molecular weight: about 1000), 140 parts by weight of phthalic anhydride and 57 parts by weight of methyl ethyl ketone, and 1 hour and 30 minutes. At 150-1
The temperature was raised to 60 ° C, and the reaction was further performed at a temperature of 150 to 160 ° C for 1 hour and 30 minutes. Then, the inside of the container was depressurized to 5 to 10 mmHg to remove the solvent and unreacted materials to obtain a carboxyl group-modified polyethylene diol.

This product had a hydroxyl value of 92 and an acid value of 45.

57 parts by weight of the carboxyl group-modified polyethylene diol, 500 parts by weight of polyethylene glycol having a hydroxyl value of 112,
47 parts by weight of tolylene diisocyanate were reacted at 90 ° C. for 3 hours to obtain a polyurethane polyol having a hydroxyl value of 51.6.

Furthermore, to 60 parts by weight of this polyurethane polyol, polyurethane polyisocyanate (trade name: 2K-LF 302A,
100 parts by weight of Dainippon Ink and Chemicals, Inc.) was mixed by stirring to obtain an adhesive composition.

The physical properties of the obtained adhesive composition are shown in Table 1.

Comparative Example 1 500 parts by weight of polyethylene glycol having a hydroxyl value of 112 and 43 parts by weight of tolylene diisocyanate were reacted at 90 ° C. for 3 hours to obtain a polyurethane polyol having a hydroxyl value of 52.0.

Furthermore, to 60 parts by weight of this polyurethane polyol, polyurethane polyisocyanate (trade name: 2K-LF 302A,
100 parts by weight of Dainippon Ink and Chemicals, Inc.) was mixed by stirring to obtain an adhesive composition.

The physical properties of the obtained adhesive composition are shown in Table 1.

Example 2 Propylene oxide adduct of glycerin (molecular weight: about 1500) was added to a flask equipped with a thermometer, a stirrer and a distillation tube.
Charge 00 parts by weight, 67 parts by weight of succinic anhydride and 53 parts by weight of toluene, raise the temperature to 150 to 160 ° C. in 1 hour and 30 minutes, and
The reaction was carried out at a temperature of 150 to 160 ° C. for 1 hour and 30 minutes. Then, the inside of the container was depressurized to 5 to 10 mmHg to remove the solvent and unreacted materials to obtain a carboxyl group-modified polypropylene diol.

This product had a hydroxyl value of 69 and an acid value of 35.

The above-mentioned carboxyl group-modified polypropylene diol 114
By weight, 500 parts by weight of polypropylene glycol having a hydroxyl value of 160, 15 parts by weight of DEG and 116 parts by weight of MDI are reacted at 90 ° C. for 3 hours to obtain a polyurethane polyol having a hydroxyl value of 69.6.

Furthermore, 40 parts by weight of this polyurethane polyol is used with polyurethane polyisocyanate (trade name: Seika Bond XC
-2310 Dainichi Seika Kogyo Co., Ltd. product) 100 parts by weight was mixed by stirring to obtain an adhesive composition.

The physical properties of the obtained adhesive composition are shown in Table 1.

Comparative Example 2 500 parts by weight of polypropylene glycol having a hydroxyl value of 160, DE
15 parts by weight of G and 107 parts by weight of MDI are reacted at 90 ° C. for 3 hours to obtain a polyurethane polyol having a hydroxyl value of 77.3.

Furthermore, 40 parts by weight of this polyurethane polyol is used with polyurethane polyisocyanate (trade name: Seika Bond XC
-2310 Dainichi Seika Kogyo Co., Ltd. product) 100 parts by weight was mixed by stirring to obtain an adhesive composition.

The physical properties of the obtained adhesive composition are shown in Table 1.

Example 3 A flask equipped with a thermometer, a stirrer and a distillation tube was charged with a caprolactone adduct of trimethylolpropane (molecular weight: about 85).
0) 1000 parts by weight, 220 parts by weight of trimellitic anhydride and 61 parts by weight of toluene were charged, and the temperature was raised to 150 to 160 ° C. in 1 hour and 30 minutes, and further reacted at a temperature of 150 to 160 ° C. for 1 hour and 30 minutes. . Then, the inside of the container was depressurized to 5 to 10 mmHg to remove the solvent and unreacted materials to obtain a carboxyl group-modified polycaprolactone diol. This compound had a hydroxyl value of 106 and an acid value of 53.

The above-mentioned carboxyl group-modified polycaprolactone diol
200 parts by weight, polyether triol 800 with a hydroxyl value of 112
By mixing parts by weight with stirring, a polyol having a hydroxyl value of 111 is obtained.
Furthermore, to 40 parts by weight of this polyurethane polyol, polyurethane polyisocyanate (trade name: ADCOAT N-
312A Toyo Ink Chemical Co., Ltd. product) 100 parts by weight was mixed by stirring to obtain an adhesive composition.

The physical properties of the obtained adhesive composition are shown in Table 1.

Comparative Example 3 100 parts by weight of polyurethane polyisocyanate (trade name: Adcoat N-312A Toyo Ink Chemical Co., Ltd. product) was stirred and mixed with 40 parts by weight of polyether triol having a hydroxyl value of 112 to obtain an adhesive composition.

The physical properties of the adhesive compositions of Examples 1 to 3 and Comparative Examples 1 to 3 were measured as follows.

That is, VMCP (aluminum vapor-deposited unstretched polypropylene) film 25 μ thick and aluminum foil 15 μ thick with the adhesive composition 1.
Apply 5g / m ² and stick each with 25μ thickness of opp (stretched polypropylene film) 40 ° C After aging for 4 days, 25 ° C
After leaving it for 1 day, the adhesive strength was measured according to JIS K-6854.

[Advantages of the Invention] The adhesive composition of the present invention has extremely good workability with a solventless laminator, and also has excellent adhesiveness, transparency and durability between a plastic film and a metal vapor deposition film or metal foil. Therefore, it is extremely effective as an adhesive for a composite laminate film.

Claims (2)

[Claims] 1. A two-part curable adhesive composition comprising a polyol or a polyurethane polyol and a polyurethane polyisocyanate, wherein at least two polycarboxylic acid hydroxyl groups remain in the polyol having a trifunctional or higher functional hydroxyl group as the polyol. Copolymerizing a polyol having a carboxyl group obtained by the reaction and a polyol having a trifunctional or higher functional hydroxyl group as the polyurethane polyol with a carboxyl group-containing polyol obtained by reacting a polycarboxylic acid so that at least two hydroxyl groups remain An adhesive composition comprising a polyurethane polyol as described above. 2. The adhesive composition according to claim 1, wherein the two-part curable adhesive composition contains essentially no organic solvent.