JP2002212530A - Adhesive composition for lamination and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for a lamination, excellent in resistance for the physical property of its content, heat resistance and retort resistance and less in transportation of the adhesive content to the content. SOLUTION: This adhesive composition for the lamination contains a polyester component treated with a thin membrane distillation for making un-reacted glycol, organic acid and oligomer which are not made as the high molecular weight in the synthesis of the polyester as a high molecular weight or removing them, or more preferably the molecule constituted by the above polyester component and containing a reactive silyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminating urethane-based adhesive composition for compounding plastic films, or between a plastic film and a metal foil such as aluminum, or a metal-deposited film. TECHNICAL FIELD The present invention relates to an adhesive composition suitable for a use having, for example, a content, and a production method thereof.

[0002]

2. Description of the Related Art In recent years, flexible packaging materials composed of lamination adhesives have been used for retort foods,
It is used for many products, including frozen foods, and enriches our diet. On the other hand, due to the components transferred from the soft packaging material, the taste and flavor inherent in foods are impaired, and problems are often regarded as problems from a sanitary viewpoint. Conventional adhesive composition for food lamination, particularly for the purpose of imparting retort resistance and content resistance, for example, the use of an epoxy resin as disclosed in JP-B-61-4864, The use of an acid anhydride compound disclosed in JP-A-61-47775 is known. These are components that improve retort resistance and content resistance, and are important components from the viewpoint of adhesive performance.
A low molecular weight epoxy resin not subjected to high molecular weight by the polyisocyanate compound, its raw material, and the point that the acid anhydride compound is eluted into the contents, which may adversely affect the taste and flavor of the food, There are still problems such as not being assured of sufficient hygienic safety. Further, for the purpose of improving the adhesive strength, the use of a silane coupling agent has been reported, for example,
JP-B-58-11912 can be mentioned. The silane coupling agents used here are also relatively low molecular weight compounds, and under conditions where sufficient cross-linking is not carried out, these silane coupling agents migrate to the contents, resulting in taste, flavor and even adhesion. The strength may be adversely affected.

[0003]

With respect to the dissolution of the adhesive component from the flexible packaging material, for example, the Food Sanitation Law (Ministry of Health and Welfare Notification Nos. 370, 84 and 20) and the US FDA (Foo)
d and DrugAdministration)
Regulations on raw materials used and management of eluting components. However, it is safer, taste,
It is also true that there is an increasing demand for lamination adhesives that do not adversely affect flavor. Based on this background, the present inventors have further improved basic physical properties required as an adhesive for lamination, for example, normal strength, heat resistance, retort strength, acid resistance, oil resistance, and the like. To conduct extensive research on lamination adhesives that can prevent the transfer of ingredients to the contents, provide more safe foods and pharmaceuticals to the public, and contribute widely to improving the health and well-being of the public. It is an object of the present invention to provide an adhesive composition for lamination and a method for producing the same.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on factors that have an adverse effect on the adhesive performance. As a result, after lamination with the adhesive composition, a relatively low-molecular compound is contained in the cured adhesive film. Was found to be a cause of lowering the adhesive strength originally expected.
In addition, an adhesive composition designed for a microscopically nonuniform cured film in which a site crosslinked by an isocyanate curing agent at a high order and a conversely low partial crosslinked or non-crosslinked site coexist. It has been found that due to changes in conditions, significant performance fluctuations may occur. Furthermore, due to these factors, not only the sufficient adhesive strength is not drawn out, but also the unique odor of the low-molecular compound still remaining in the adhesive cured film is transferred to the contents, impairing the original taste and flavor of the food. I discovered that it leads to such things. That is, the present invention solves these problems by a method of chemically increasing the molecular weight of the low-molecular compound that migrates to the contents and a method of physically removing the low-molecular compound that still remains. At the same time found a way to solve it. That is, the present invention relates to an adhesive composition composed of a polyester component in which unreacted glycols, organic acids, and oligomers that have not been polymerized during polyester synthesis have been polymerized and distilled off by thin film distillation. The adhesive composition containing a reactive silyl group in the molecule composed of a polyester component can be used for epoxy resin and low-molecular acid anhydride, which were conventionally required, without adding content resistance and retort resistance. The present invention has been found to be extremely excellent in properties and that the migration of the adhesive component is extremely reduced, and it is possible to improve the strength of the adhesive and to make it hard to adversely affect the taste and flavor of the food. Completed.

Accordingly, the present invention provides a polyester component comprising at least one of unreacted glycols, organic acids, and oligomers which have not been converted to a high molecular weight during the synthesis of the polyester, which has been converted to a high molecular weight and / or removed by a thin film distillation treatment. The above object is achieved by providing an adhesive composition for lamination characterized by the following. Further, the present invention provides a method for producing a lamination adhesive composition containing a polyester component as a main component,
A step of synthesizing the polyester polyol and a step of thinning and / or removing at least one of unreacted glycols, organic acids, and oligomers which have not been polymerized during the synthesis of the polyester polyol by thin film distillation. An object of the present invention is to provide a method for producing a lamination adhesive composition. The above-mentioned polyester component is not particularly limited as long as it can be used as an adhesive for lamination, but a part or all of the polyester component can be a polyester component containing a reactive silyl group in a molecule. It can be a polyester component having a reactive silyl group and a carboxyl group in it, and further, it can be a mixture of a polyester component having a reactive silyl group in the molecule and a polyester component having a carboxyl group in the molecule. it can. With these, it is possible to satisfy both the requirement of low elution and the requirement from the viewpoint of adhesive performance such as improvement of adhesive strength. This reactive silyl group is desirably introduced into the polyester component molecule by bonding the silane coupling agent and the polyester component by reaction with at least one isocyanato group. The lamination adhesive composition of the present invention can also be implemented by adding a polyisocyanate as a curing agent. In addition, in claims 1 and 7 of the present application, "the molecular weight is increased and / or removed by the thin film distillation treatment" is described, but both the action of increasing the molecular weight and the action of the removal are generally performed by the thin film distillation treatment. Therefore, in the following description, it is described as "high molecular weight and removal (distillation)".

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In order to obtain an adhesive composition according to the present invention, a step (1) of obtaining a polyester polyol by reacting with a glycol and a polybasic acid or a polybasic acid anhydride; The step (2) of increasing the molecular weight and / or distilling off the contained high molecular weight glycols, organic acids and oligomers by thin film distillation treatment is performed. More desirably, after the step (2) of increasing the molecular weight and / or distilling off by thin-film distillation, a step (3) of modifying the alkoxysilane compound containing an organic moiety into a polyester component is performed.

Synthesis step of polyester polyol (1)
In this case, the esterification method is not particularly limited, and can be synthesized by a method known in the art. Specifically, polyester synthesis is performed by dehydration and ring-opening reaction of glycol with an organic acid compound such as polybasic acid or acid anhydride, or polyester synthesis is performed by ring-opening reaction of cyclic ester. As the glycol component, known glycols can be used, and ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and
Examples include trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol having three or more hydroxyl groups in the molecule. As the polybasic acid component, well-known polybasic acids can be used, and adipic acid, 1,4- Cyclohexanedicarboxylic acid, fumaric acid, maleic acid, succinic acid, sebacic acid, terephthalic acid, isophthalic acid, trimellitic acid, and anhydrides thereof, and the like, and one or more selected from these groups Can be used. Examples of the cyclic ester include caprolactone and the like, which can be synthesized by ring-opening polymerization under an appropriate catalyst.

The polyester polyol used in the present invention is designed so as to contain at least two hydroxyl groups in one molecule of the obtained polyester, and preferably has a number average molecular weight of about 7,000 or less. Preferably it is about 5,000 to 1,000. This is excellent in workability in the subsequent thin film distillation treatment step (2), and has high removal efficiency of low molecular compounds. On the other hand, when the number average molecular weight exceeds 7000, it is necessary to raise the thin film distillation treatment temperature, which is economically disadvantageous, and a part of the polyester is decomposed due to the equilibrium reaction of the ester bond. Fear arises.

Further, a carboxyl group can be introduced into the polyester polyol of the present invention for the purpose of further improving strength and acid resistance. JP-A-3-281
As disclosed in Japanese Patent No. 589, the effect of improving the strength by introducing a carboxyl group is exhibited also in the present invention, and furthermore, the effect of improving the acid resistance is provided.

The carboxyl group can be introduced at the time of polyester synthesis, or at the time of urethane chain length described later. As a method for synthesizing a polyester polyol containing a carboxyl group, for example, a hydroxyl group obtained by reacting a polyol having three or more hydroxyl groups with an acid anhydride as disclosed in JP-A-3-281589 is disclosed. A polycarboxylic acid polyol such that at least two remain, or a polycarboxylic acid polyol such that at least two hydroxyl groups obtained by dehydration esterification of one molecule of polyester triol and one molecule of dicarboxylic acid remain, and A polycarboxylic acid polyol having at least two hydroxyl groups obtained by modifying by esterification or urethanization reaction using a diol monocarboxylic acid such as dimethylolpropionic acid or dimethylolbutanoic acid as a starting material may be used. As described above, the polyester used in the present invention is designed to have at least two hydroxyl groups in one molecule. The polyester diol is not derived from a terminal carboxyl group with an acid anhydride or the like. The terminal carboxyl group polyester containing only two or less, a chain length by urethanization described later,
Furthermore, it hinders the increase in the molecular weight after the curing agent is blended, and even if the normal strength is sufficient, it may cause a decrease in the adhesive performance especially in heat treatment and retort sterilization treatment, and it is easy to transfer the low molecular compound to the contents. It is desirable that one molecule contains at least two hydroxyl groups.

On the other hand, the content of the carboxyl group does not need to be one or more in one molecule of the polyester polyol, and the content of the carboxyl group is expressed by an acid value, and the acid value of the obtained resin is 0 to 40 mgKOH /. g is good, preferably 0 to 20 mgKOH / g. Acid value is 3mg
In the case of KOH / g or less, delamination may occur in storage of an acidic food as a content. As described above, when the amount of the carboxyl group in the polyester polyol molecule is insufficient or when the carboxyl group is not intentionally introduced, a method of introducing the carboxyl group depending on the urethane chain length can be adopted. In addition, the acid value is 20
In the case of mgKOH / g or more, a tendency that water resistance is poor is observed.

Since the above-mentioned carboxyl group-containing polyester polyol is a compound containing a hydroxyl group and a carboxyl group, it is important to accurately determine the reaction end point in the synthesis thereof, and it is necessary to control the dehydration amount and the acid value. it can.

The polyester polyol thus obtained still contains unreacted glycols, organic acids and oligomers. One of the methods for achieving both the strength improvement and the migration suppression of the adhesive component in the present invention is to increase the molecular weight and distill off these low molecular weight compounds by thin film distillation treatment as described below. Different from polyester synthesis. That is, in synthesizing a conventional polyester, for example, a method of reducing unreacted glycol or polybasic acid by polymerizing to a high molecular weight without leaving an acid value, etc. The oligomer still remains, but rather, in order to increase the molecular weight, by using severe conditions at high temperatures or using a large amount of esterification catalyst, the resulting resin emits a burning smell or dehydration reaction of hydroxyl group Conversion to vinyl bonds occurred and did not always give good results. The high molecular weight and removal of unreacted glycols, organic acids and oligomers by thin-film distillation of the present invention can be said to be a means for solving these problems. Hereinafter, the thin film distillation step (2) will be described.

The polyester polyol and the carboxyl group-containing polyester polyol are subjected to a step (2) of continuously increasing the molecular weight of unreacted glycols, organic acids and oligomers and distilling them off by a thin film distillation apparatus.
The oligomer described in the present application is a monool monocarboxylic acid monoesterified with one molecule of glycol and one molecule of dicarboxylic acid, an oligomer diesterified with one molecule of glycol and one molecule of dicarboxylic acid, and further, It is formed within two molecules of glycol and two molecules of dicarboxylic acid, and means a compound having a molecular weight of about 700 or less. The thin film distillation treatment conditions are 100 ° C to 300 ° C,
The treatment is performed under heating and reduced pressure conditions of 50 Torr to 0.01 Torr, and may be performed two or more times as necessary.

The compounds to be increased in molecular weight and distilled off by thin-film distillation are unreacted glycols and organic acids, and the above-mentioned oligomer components. The molecular weight of the polyester before and after the treatment varies depending on the thin-film distillation treatment conditions. The molecular weight is increased from about 1.1 to 1.3 times in average molecular weight, and the content of glycol, organic acid and oligomer in the polyester raw material is reduced from about 2/3 to 1/40.

These oligomers contain a component having no group that reacts with the isocyanate group, hinders the increase of the molecular weight in the subsequent chain length and crosslinking by the polyisocyanate compound, and is evaluated as an adhesive cured film. In particular, it adversely affects heat resistance, and the disadvantage that the unique odor of low-molecular-weight compounds migrates to the contents after the contents are packed as a container, which has a disadvantageous effect on adhesion performance and taste and flavor. Is what you are doing.

Therefore, as described above, the present invention provides a method for forming a polyester polyol or a carboxyl group-containing polyester polyol (1) by high molecular weight distillation and undistillation of unreacted glycols, organic acids and oligomers by thin-film distillation (2). It is an object of the present invention to provide an adhesive composition capable of improving force and suppressing migration of an adhesive component.

Next, a method for improving the adhesion performance by the step (3) of modifying the silane coupling agent to the polyester and suppressing the transfer of the adhesive component will be described below.

According to Japanese Patent Publication No. 58-11912,
Epoxy, an alkoxysilane compound containing an organic moiety containing an amino group or the like, a method of adding a so-called silane coupling agent or introducing the polymer into a polymer is disclosed, and the adhesive performance,
Especially, the retort resistance is improved. In the present invention, these silane coupling agents can be simply added and used as a mixture.However, from the viewpoint of low odor and low elution in the present invention, the modification of the silane coupling agent to the polymer is not effective. This is a desirable method for achieving the object of the present application.

That is, when these silane coupling agents are also evaluated from the viewpoint of transfer to the contents, they are one of the factors that cause a problem in taste and flavor. In addition, it was found that the transfer to contents can be suppressed while maintaining the adhesive performance while further improving the adhesiveness, and the following invention was completed.

The alkoxysilane compound containing an organic moiety is a silane coupling agent having an amino, epoxy, mercapto or isocyanato group, and specifically, γ-glycidoxypropyltrimethoxysilane, γ
-Glycidoxypropylmethyldimethoxysilane, γ-
Glycidoxypropylmethyldiethoxysilane, N-β
(Aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane , Γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane and the like, and one or more kinds selected from these groups can be used.

The method of the step (3) of modifying the silane coupling agent to the polyester is determined in consideration of the reactivity of the organic portion of the silane coupling agent. The amino group-containing silane coupling agent having a high content can introduce a reactive silyl group into the polyester polyurethane polyol component by urethanization with a polyisocyanate, and the epoxysilane reacts separately with a primary or secondary amine compound. After reacting with an active hydrogen-containing aminosilane or a hydroxyl group-containing silane and then reacting with an isocyanate group, a reactive silyl group can be introduced into the polyester polyurethane polyol in the same manner.For isocyanatosilane, a urethane bond is directly attached to the polyester polyol. Can be introduced and denatured Kill. The polyester to be modified may be either a polyester polyol or a carboxyl group-containing polyester polyol, but the modification of the reactive silyl group to the polyester having a high acid value is preferably performed under mild conditions, at a high temperature for a long time. Care must be taken under the conditions, because the reaction between silyl groups may induce partial gelation. The amount of modification of the reactive silyl group to the polyester is preferably 0.1 to 5% by weight, more preferably 0.3 to 2.0% by weight, based on the solid content of the final adhesive composition as a silane coupling agent. It is. 0.
When the content is less than 3% by weight, the water resistance and hot water resistance to metal foils and vapor-deposited films are reduced, and the modification of 2.0% by weight or more does not lead to a remarkable improvement in performance.
It is also disadvantageous economically.

In the adhesive composition of the present invention, the polyester polyol can be chain-lengthened with polyisocyanate. The urethane chain length by the isocyanate compound can be performed simultaneously with the modification of the above-described alkoxysilane compound containing an organic moiety, or can be performed before or after the modification of the alkoxysilane.

The isocyanate compound used for the urethane chain length is mainly a diisocyanate compound, and if necessary, a polyisocyanate compound can be used. The type of isocyanate includes aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate, and specifically, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, naphthalene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, m-xylylene diisocyanate, α, α, α ′, α′-tetramethyl-m -Xylylene diisocyanate, m-hydrogenated xylylene diisocyanate, 4,4'-hydrogenated diphenylmethane diisocyanate, norbornene diisocyanate, and the like, and further, those in which trimethylolpropane adduct, nurate, buret, and the like can be used. And one or more selected from these groups can be used, and desirably isophorone diisocyanate, m-xylylene diisocyanate or a derivative thereof.

In using the adhesive composition comprising the polyester component of the present invention, the adhesive composition is used as a main component, and the polyisocyanate component is used as a curing agent. As the curing agent, the polyisocyanate component described above can be used as appropriate, but it is preferable to use the polyisocyanate component in an amount of 1.0 to 8.0 times the hydroxyl equivalent of the polyester polyurethane polyol as the main component, More preferably, the compounding amount is 1.2 to 5.0 times the amount. When the amount is less than 1.2, it tends to exhibit adhesive performance with poor heat resistance or cause tack to remain. In some cases, the packaging material becomes brittle and easily breaks, which is not only a factor that lacks the strength of the container, but also is economically disadvantageous. Further, it is desirable to set these compounding ratios in consideration of the surface condition of the film substrate, the working environment humidity, and the like.

The specific method of using the lamination adhesive composition obtained according to the present invention is as follows: a non-solvent lamination method in which a heating agent is heated so as to have an appropriate viscosity and a curing agent is blended; Dry lamination method in which the agent is diluted and adjusted to a suitable coating viscosity with a solvent. In any case, apply the compounding adhesive to the film surface and paste it with another film adhesive surface,
In the case of the dry lamination method, it is necessary to evaporate the organic solvent by passing through a drying oven and then bond the film to another film. The laminated film composite needs to be cured under a heated atmosphere in order to complete the reaction with the curing agent. As the solvent used in the dry lamination method, a solvent that does not contain a hydroxyl group or an amino group that reacts with an isocyanato group is used, and specific examples include ethyl acetate and methyl ethyl ketone. The amount of the adhesive applied is preferably in the range of about 2.0 to 5.0 g / m ^{2 in} a dry state.
This is determined in consideration of the film type and the film surface condition. The adhesive composition of the present invention can remarkably exhibit its effect on the bonding of food and pharmaceutical packaging materials, but its use is not limited to these packaging materials, such as the bonding of industrial products, It can be used for various applications for lamination.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples of the present invention and comparative examples, but the present invention is not limited to these examples.

Synthesis of Polyester Polyol (P) Ethylene glycol (42.0 g), 1,6-hexanediol (200.0 g), neopentyl glycol (150.0 g), isophthalic acid (400.0 g), sebacic acid ( 160.0 g) and adipic acid (48.0).
g) was added thereto, and a dehydration esterification reaction was performed at an internal temperature of 180 to 220 ° C. while heating and stirring. Resin acid value is 2.0mgK
OH / g was confirmed, the reaction was terminated, and a polyester polyol (hereinafter, referred to as polyester (P)) was obtained.
I got

Example 1 Polyester (P) Thin Film Distillation Treatment 1 and Urethane Chain Length (PF-1)
The treatment was performed continuously at a temperature of 0.1 ° C. and a reduced pressure of 0.1 Torr. The acid value of the obtained polyester was 0.3 mgKOH / g. In addition, the distillate is 0.1% based on the treated polyester.
It was 42% by weight. The distillate was unreacted glycol, polybasic acid, and oligomers thereof from analysis.
Subsequently, the polyester (100
g), IPDI (6.0 g) is added, and the internal temperature is 120 ° C. to 1 ° C.
The urethanization reaction was performed at 50 ° C. It was confirmed by IR spectrum that the absorption of isocyanate had disappeared, and ethyl acetate (106.0 g) was added to obtain a polyester polyurethane polyol (PF-1) having a solid content of 50%.

Example 2 Polyester (P) Thin Film Distillation Treatment 2 and Urethane Chain Length (PF-2)
The treatment was continuously performed at a temperature of 0 ° C. and a reduced pressure of 0.05 Torr. The acid value of the obtained polyester was 0.1 mgKOH / g. The distillate was 0.55% by weight based on the treated polyester. The distillate was unreacted glycol, polybasic acid, and oligomers thereof from analysis. Subsequently, the polyester (1
00g), IPDI (5.8 g) was added, and the internal temperature was 120 ° C.
The urethanization reaction was performed at ~ 150 ° C. It was confirmed by IR spectrum that the absorption of isocyanate had disappeared, and ethyl acetate (105.8 g) was added, and the solid content was 50%.
(PF-2) was obtained.

Example 3 Reactive Silyl Group Modification of Polyester Treated with Thin Film Distillation 1 (PFS-1) Polyester Treated with Thin Film Distillation 1 (100.0 g)
Was added to isophorone diisocyanate (3.5 g),
By the same operation as in Comparative Example 3, the intended reactive silyl group-containing polyester polyurethane polyol (PFS-1) was obtained.

Example 4 Reactive Silyl Group Modification of Polyester Treated with Thin Film Distillation Process 2 (PFS-2) Polyester Treated with Thin Film Distillation Process 2 (100.0 g)
Then, isophorone diisocyanate (3.4 g) was added thereto, and the same operation as in Comparative Example 3 was carried out to obtain a desired reactive silyl group-containing polyester polyurethane polyol (PFS-2).

Example 5 Carboxyl group modification of polyester subjected to thin film distillation treatment 1 (PFA-1) Polyester subjected to thin film distillation treatment 1 (100.0 g)
A separately prepared trimellitic anhydride and trimethylolpropane reactant (acid value 344 mg KOH / g) (1.
6 g) to make the mixture uniform, then add isophorone diisocyanate (6.8 g), react at an internal temperature of 120 ° C. to 150 ° C., confirm that the absorption of the isocyanate has disappeared by IR spectrum, and confirm with ethyl acetate (108. 4 g) was added to obtain the desired carboxyl group-containing polyester polyurethane (PFA-1).

Example 6 Carboxyl group modification of polyester subjected to thin film distillation treatment 2 (PFA-2) Polyester subjected to thin film distillation treatment 2 (100.0 g)
A separately prepared trimellitic anhydride and trimethylolpropane reactant (acid value 344 mg KOH / g) (1.
6 g) to make the mixture uniform, then add isophorone diisocyanate (6.6 g), and carry out the same operation as in Example 5 to obtain the desired carboxyl group-containing polyester polyurethane (P).
FA-2) was obtained.

Example 7 Modification of Silyl and Carboxyl Groups of Polyester Treated with Thin Film Distillation 1 (PFA)
S-1) Polyester subjected to thin-film distillation treatment 1 (100.0 g)
A separately prepared trimellitic anhydride and trimethylolpropane reactant (acid value 344 mg KOH / g) (1.
After adding 6 g) to make the mixture uniform, isophorone diisocyanate (4.6 g) was added and reacted at an internal temperature of 120 ° C to 150 ° C, and it was confirmed by IR spectrum that the absorption of isocyanate had disappeared. Ethyl acetate (70.0
g) was added and dissolved. To this, trimethylolpropane (0.73 g) was added, isophorone diisocyanate (4.6 g) was added at room temperature, and γ-aminopropyltriethoxysilane (1.2 g) was added dropwise. Further, the reaction was carried out under reflux conditions until the absorption of isocyanate disappeared by the IR spectrum, and ethyl acetate (42.73 g) was added to obtain the desired polyester polyurethane polyol having a silyl group and a carboxyl group (PFAS-1).

Example 8 Modification of Polyester Treated with Thin Film Distillation 2 by Silyl Group and Carboxyl Group (PFA)
S-2) Polyester (100.0 g) subjected to thin film distillation treatment 2
A separately prepared trimellitic anhydride and trimethylolpropane reactant (acid value 344 mg KOH / g) (1.
After adding 6 g) to make the mixture uniform, isophorone diisocyanate (4.4 g) was added, and the same operation as in Example 7 was carried out to obtain a target silyl group- and carboxyl group-containing polyester polyurethane polyol (PFAS-2).

"Comparative Example 1" Urethane modification of polyester (P) and addition of silane coupling agent Isophorone diisocyanate (6.2 g) was added to polyester (P) (100.0 g).
A urethanization reaction was performed at 0 ° C., and after confirming that the absorption of isocyanate had disappeared by IR spectrum, ethyl acetate (107.2 g) was added and dissolved. To this, γ-glycidoxypropyltrimethoxysilane (1.2 g) was added to obtain Comparative Example 1.

"Comparative Example 2" Modification of carboxyl group of polyester (P) and addition of silane coupling agent Trimellitic anhydride and trimethylolpropane reactant (acid value) separately prepared for polyester (P) (100.0 g) After adding 344 mg KOH / g) (1.6 g) to make the mixture uniform, isophorone diisocyanate (7.2 g) was added and reacted at an internal temperature of 120 ° C. to 150 ° C., and it was confirmed by IR spectrum that the absorption of isocyanate had disappeared. Then, ethyl acetate (110.0 g) was added and dissolved. To this, γ-glycidoxypropyltrimethoxysilane (1.2 g) was added to obtain Comparative Example 2 of interest.

Comparative Example 3 Reactive Silyl Group-Modified Polyester (P) (PS-1) To 100 g of polyester (P), 4.0 g of isophorone diisocyanate was added, and the internal temperature was 120 ° C. to 150 ° C.
A urethanization reaction was performed at ℃. It was confirmed by IR spectrum that the absorption of isocyanate had disappeared, and ethyl acetate (70.0 g) was added and dissolved. To this, trimethylolpropane (0.73 g) was added, isophorone diisocyanate (4.6 g) was added at room temperature, and γ-aminopropyltriethoxysilane (1.2 g) was added dropwise. Further, the reaction was carried out under reflux conditions until the absorption of the isocyanate disappeared by the IR spectrum, whereby Comparative Example 3 was obtained.

The outlines of the above Examples and Comparative Examples are summarized in Table 1.

[0041]

[Table 1]

[Evaluation] Resins obtained by Examples and Comparative Examples The following (1) and (2) were used as laminate adhesives, and the following tests (3) to (6) were performed.

(1) Formulation A curing agent (H-
4) (Aqueous polyisocyanate curing agent, manufactured by Rock Paint Co., Ltd.) was blended so that the weight ratio of the main agent to the curing agent was 10: 1, and the solid content was adjusted to 25% with ethyl acetate.

(2) Lamination The amount of the blended adhesive applied by a dry laminator.
5 g / m ² of polyethylene terephthalate film (P
ET) (12 μm) and aluminum foil (AL) (9 μm), and then the aluminum foil and unstretched polypropylene film (CPP) (60 μm) were bonded together.
Aging was performed for 3 days at ℃.

(3) Measurement of Adhesive Strength The normal strength, the wet strength after high retort, and the heat resistance between PET / AL and AL / CPP were measured, and the results are shown in Table 2. A test piece having a width of 15 mm was prepared, and the strength was measured by T-peeling at a tensile speed of 300 mm / min using a tensile tester. The normal strength is the peel strength at room temperature, and the wet strength after high retort is 135.
After heat sterilization at 30 ° C. for 30 minutes, the peel strength is the peel strength when water is applied to the peel interface, and the heat-resistant strength is the peel strength in a 120 ° C. atmosphere.

(4) Content resistance test A laminated film was prepared into a flat bag with an inner size of 15 cm × 20 cm, and vinegar, ketchup and sesame oil were filled as contents with a total of 15 g at a weight ratio of 1: 1: 1. And 135
Heat sterilization was performed at 30 ° C. for 30 minutes. Furthermore, this is 40 ° C
After storing in an atmosphere for 10 days and opening the bag, the appearance of each laminate and the strength were measured. Table 3 shows the results.

(5) Dissolution test A bag of a laminate film having a size of 15 cm × 20 cm was prepared, and activated carbon treated ion-exchanged water (1
5 g) and sterilized by heating at 135 ° C. for 30 minutes. The contents were extracted three times with chloroform (10 g),
Use a rotary evaporator for the chloroform phase (2m
After concentrating to 1), evaluation was performed using a gas chromatograph mass spectrometer. Table 4 shows the results.

(6) Taste evaluation The extracted water (contents) obtained by the evaluation (5) was diluted 5-fold with activated carbon-treated ion-exchanged water, and the activated carbon-treated ion-exchanged water was used as a blank to give five panelists. The taste was evaluated in comparison with the blank. Table 5 shows the results.

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

[0052]

[Table 5]

As is clear from the above examples, the lamination adhesive obtained according to the present invention is excellent in the adhesive strength required as a packaging material, in particular, heat resistance, hot water resistance and content resistance. It was confirmed that the transfer of the adhesive component to the composition was extremely small, and that the original flavor and taste of the content were not adversely affected.

[0054]

The invention of claims 1 to 6 of the present invention is intended to provide an adhesive for lamination which is excellent in adhesive strength, especially heat resistance, hot water resistance, and content resistance, and has very little migration of the adhesive component to the content. If it is used as an adhesive for packaging materials such as food, it can provide consumers with extremely safe foods, which are extremely unlikely to adversely affect the original flavor and taste of the contents. It was something that could be provided. In particular, the inventions of claims 2 to 6 can provide an adhesive for lamination which can satisfy both the improvement of adhesive strength and the requirement of low elution. The invention of claim 7 of the present application has been able to provide a method for producing a lamination adhesive composition exhibiting the above effects.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eiichi Nezaki 2-37-2 Minamisuna, Koto-ku, Tokyo Inside Rock Paint Co., Ltd. Tokyo Branch (72) Inventor Yuji Ogino 2-37-2 Minamisuna, Koto-ku, Tokyo Rock Paint Co., Ltd. Tokyo Branch (72) Inventor Yoshinori Takanobashi 2-37-2 Minamisuna, Koto-ku, Tokyo Rock Paint Co., Ltd. Tokyo Branch F Term (Reference) 4J040 ED011 ED041 ED051 ED161 EF111 GA07 GA31 KA16 LA01 LA07 LA08 LA11 MA02 MA10 MB03 NA08 QA01 QA09

Claims (7)

[Claims] The present invention is characterized in that at least one of unreacted glycols, organic acids, and oligomers which have not been polymerized at the time of polyester synthesis has a polyester component as a main component which has been polymerized and / or removed by thin-film distillation. Lamination adhesive composition. 2. The lamination adhesive composition according to claim 1, wherein at least a part of the polyester component is a polyester component containing a reactive silyl group in a molecule. 3. The polyester component according to claim 1, wherein at least a part of the polyester component is a polyester component containing a reactive silyl group and a carboxyl group in a molecule.
The adhesive composition for lamination according to the above. 4. The lamination according to claim 1, wherein at least a part of the polyester component is a polyester component containing a reactive silyl group in the molecule and a polyester component containing a carboxyl group in the molecule. Adhesive composition. 5. The polyester component containing a reactive silyl group in the molecule, wherein the silane coupling agent and the polyester component are bonded by reaction with at least one isocyanato group. The adhesive composition for lamination according to any one of items 1 to 4, wherein 6. The lamination adhesive composition according to claim 1, wherein a polyisocyanate is added as a curing agent. 7. A method for producing an adhesive composition for lamination containing a polyester component as a main component, wherein a step of synthesizing a polyester polyol, the step of synthesizing unreacted glycols, organic acids and oligomers which have not been polymerized during the synthesis of the polyester polyol. A process of increasing the molecular weight and / or removing at least one of the above by thin-film distillation treatment.