JPH05311146A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide the two-pack curable composition consisting of a main agent composed mainly of a polyurethane polyol and a curing agent composed mainly of a specific polyurethane polyisocyanate and having extremely excellent viscosity stability and solution stability during storage. CONSTITUTION:The composition is composed of (A) a main agent composed mainly of a polyurethane polyol and (B) a curing agent composed mainly of a polyurethane isocyanate produced by extending the chain of a polyurethane diisocyanate with a polyol having >=3 hydroxyl functional groups (preferably polytetramethylene ether glycol, etc., having a molecular weight of 300-3,000). The polyurethane diisocyanate is produced from a polyurethane diisocyanate having >=2 NCO functional groups and derived from a diol having two hydroxyl functional groups (preferably polyethylene adipate, etc., having a molecular weight of 300-10,000) and a diisocyanate having two NCO functional groups (preferably tolylene diisocyanate, etc.). Preferably, the viscosity ratio of the component A to the component B (cps/25 deg.C) is adjusted to 1:1 and the mixing ratio of A:B is selected to be 1:1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for a composite laminate film, and more specifically, it has excellent adhesiveness when a composite film is produced by laminating various plastic films, metal vapor deposition films, papers and the like. The present invention relates to a polyurethane adhesive composition that imparts transparency and durability.

[0002]

2. Description of the Prior Art Plastic films such as polyethylene, polypropylene, polyethylene terephthalate and nylon, or composite films obtained by laminating these plastic films and metal vapor deposition films, papers, woven fabrics, etc. in multiple layers are used for foods, pharmaceuticals, cosmetics and household products. Widely used as a soft packaging material for products. Conventionally, a one-component moisture curing type or two-component curing type polyurethane adhesive has been used for bonding the above-mentioned composite film.

[0003]

The one-component moisture-curable polyurethane adhesive containing polyisocyanate or polyurethane polyisocyanate as a main component does not require the two-component compounding work required for the two-component curing type. Although it has excellent workability, moisture is indispensable for curing the adhesive, and the supply of moisture to the adhesive layer is greatly affected by the ambient environment conditions. was there. On the other hand, a two-component curing type polyurethane adhesive containing a polyol or a polyurethane polyol as a main component and a polyisocyanate or a polyurethane polyisocyanate as a curing agent is generally superior in adhesive strength as compared with a one-component moisture-curing type adhesive, and can bond a composite film. The curing of the layer is not easily affected by the surrounding environment, stable bonding processing is possible, and it is advantageous over the one-component curing type adhesive. Therefore, most of polyurethane adhesives are two-component curing type. However, among the above-mentioned two-component curing type polyurethane adhesives, those using polyisocyanate or a low molecular weight isocyanate adduct as a curing agent have a large isocyanate content, and therefore the compounding ratio with the main agent is 1:10 to 1 Since it is extremely different from: 20, there was a large variation in the compounding ratio, which resulted in a variation in the adhesive performance. In addition, the viscosity is generally several thousand [cp
s / 25 ° C] to several tens to several hundreds [cps / 25 ° C]
Since the viscosity difference is extremely low, there was a defect that the mixing and mixing properties during the mixing operation were poor. Furthermore, in order to overcome the above-mentioned drawbacks, the isocyanate content is lowered by increasing the molecular weight, and the compounding ratio with the main agent is brought close to 1: 1 and at the same time, the viscosity is also increased, and the compounding characteristics are excellent. A curing agent mainly composed of a polyurethane polyisocyanate obtained by reacting a polyisocyanate with a trifunctional or higher functional polyol so that a group remains, or a polyurethane polyisocyanate obtained by chain extension of the polyurethane polyisocyanate with a small amount of a diol is generally widely used. However, these polyurethane polyisocyanate-based curing agents gradually increase in viscosity during the storage period until they are mixed with the base resin, and the viscosity when actually using an adhesive is too high. Workability remarkably deteriorated, the stability of the solution was impaired, and turbidity occurred. There was a defect that is. As a result of intensive studies to eliminate the above-mentioned deficiencies of the prior art, the present inventors obtained a diol having 2 hydroxyl functional groups and a diisocyanate having 2 isocyanate functional groups as the main components of the curing agent. When a polyurethane diisocyanate having substantially 2 functional groups of isocyanate groups is chain-extended with a polyol having 3 or more hydroxyl group functional groups, viscosity stability and solution stability during storage are obtained. The inventors arrived at the present invention by finding that they have extremely excellent performance.

[0004]

That is, the present invention comprises a main agent containing polyurethane polyol as a main component and a curing agent containing polyurethane polyisocyanate as a main component.
In the liquid-curable polyurethane adhesive composition, a polyurethane diisocyanate having substantially 2 isocyanate functional groups obtained from a diol having 2 hydroxyl functional groups and a diisocyanate having 2 isocyanate functional groups as the polyurethane polyisocyanate To
It is intended to provide an adhesive composition characterized by using a polyurethane polyisocyanate obtained by chain extension with a polyol having a hydroxyl functional group of 3 or more. Hereinafter, the present invention will be described in more detail.

The polyurethane diisocyanate having substantially 2 functional groups in the isocyanate group, which is particularly used as a curing agent component in the two-component curable polyurethane adhesive composition of the present invention, has 2 hydroxyl functional groups. It is obtained by reacting a diol and a diisocyanate having an isocyanate group of 2 functional groups by a conventional method so that an isocyanate group remains at the terminal of the molecule.
At this time, it is desirable to avoid side reactions that cause branching in the molecular chain as much as possible. That is, it is essential to obtain a linear molecular structure as linear as possible from a diol having a hydroxyl functional group of 2 and a diisocyanate having an isocyanate functional group of 2. When a side reaction that causes branching in the molecular chain is severe, even if a diol having 2 hydroxyl functional groups and a diisocyanate having 2 isocyanate functional groups are used, the number of functional groups of isocyanate groups is substantially increased. No polyurethane diisocyanate having a value of 2 can be obtained, and a polyurethane polyisocyanate having a functional group of an isocyanate group larger than 2 is substantially obtained, which is one of the most important effects of the present invention. It is not preferable because the stability of excellent viscosity in (3) is impaired.

The above-mentioned diol having 2 hydroxyl functional groups, which is used to obtain a polyurethane diisocyanate having 2 isocyanate functional groups, is a conventionally known bifunctional polyol used in ordinary polyurethane production. is there. These bifunctional polyols are used alone or in combination of two or more. Preferred examples of such a conventionally known bifunctional polyol include, for example,
Polyethylene adipate having a molecular weight of 300 to 10,000, polyethylene propylene adipate, polyethylene butylene adipate, polydiethylene adipate, polybutylene adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, polytetramethylene ether glycol, poly ε-caprolactoneol, polyhexamethylene adipate, polycarbonateol, polyethylene glycol, polypropylene glycol and the like, and bifunctional polyols thereof, and a small amount of 2
There is a bifunctional polyurethane polyol which can be obtained by reacting with a diisocyanate having an isocyanate group having a functional number of 2 according to a conventional method in combination with a functional chain extender.
Further, here, the bifunctional chain extender that may be used to obtain the bifunctional polyurethane polyol is ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, water. Etc. However, the use of too many bifunctional chain extenders makes it difficult to obtain one of the most important effects of the present invention, that is, excellent solution stability during storage of the curing agent, and therefore is possible. It is preferable to keep the amount as small as possible.

In the present invention, the diisocyanate having an isocyanate group having a functional number of 2 used to obtain a polyurethane diisocyanate having an isocyanate group having a functional number of 2 is at least 2 in the aliphatic or aromatic compound. Is a compound having an isocyanate group, and is a bifunctional organic polyisocyanate that has been widely used as a raw material for synthesizing a polyurethane resin. Any of these known bifunctional organic polyisocyanates are useful in the present invention. Particularly preferred difunctional organic polyisocyanates include, for example, 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, methylene diisocyanate,
4,4'-methylenebis (phenyl diisocyanate),
Durylene diisocyanate, 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, 4,4-diisocyanate dibenzyl, 1,4-tetramethylene diisocyanate, 1,6-tetramethylene diisocyanate, 1,1
Examples thereof include 0-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylene diisocyanate, 4,4-methylene bis (cyclohexyl diisocyanate), 1,5-tetrahydronaphthalene diisocyanate, and isophorone diisocyanate.

Next, a polyol having 3 or more hydroxyl functional groups capable of chain elongation of a polyurethane diisocyanate having substantially 2 isocyanate functional groups, which is used in the present invention, is a conventionally known polyol used in ordinary polyurethane production. Is a trifunctional or higher polyfunctional polyol. These polyfunctional polyols are used alone or in combination of two or more. Preferred examples of conventionally known trifunctional or higher polyfunctional polyols include, for example, polytetramethylene ether glycol having a molecular weight of 300 to 3000, polyε-caprolactoneol, polycarbonateol, polyethylene glycol, polypropylene glycol and the like. , And trimethylolethane, trimethylolpropane, glycerin, triethanolamine,
Examples include quadrol and sorbitol.

The above-mentioned curing agent containing polyurethane polyisocyanate as a main component has a ratio of the viscosity [cps / 25 ° C.] of the main agent to the curing agent of 1 in order to improve the mixing and mixing property.
3 to 3 to 1 (0.333 ≦ base viscosity / hardening agent viscosity ≦
3.00) (particularly preferably 1 to 1), and a set compounding ratio of the main agent to the curing agent (the mixing ratio of the main agent to the curing agent is 1 to 1 in order to improve the mixing and metering property). In the range of 3 to 3 to 1, particularly preferably 1 to 1), the number of functional groups of the hydroxyl group is such that the equivalent ratio of the isocyanate group to the active hydrogen group falls within the range of 1 to 10, preferably 1.2 to 5. 2 types of diol, molecular weight, blending ratio, blending amount, type of diisocyanate having 2 functional groups of isocyanate group, blending ratio, blending amount, and substantially 2 functional groups of isocyanate group obtained from these It can be obtained by adjusting the type, the molecular weight, the blending ratio, the blending amount, and the non-volatile content of the polyol having 3 or more functional groups of the hydroxyl groups that cause the chain elongation of the polyurethane diisocyanate. In the adhesive composition of the present invention, the curing agent containing polyurethane polyisocyanate as the main component and the main component containing polyurethane polyol as the main component are blended at a predetermined blending ratio and used.

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 A flask equipped with a nitrogen inlet tube, a thermometer, a stirrer, and a distillation tube was charged with 700 parts by weight of polypropylene glycol (molecular weight: about 700, bifunctional) as a polyol component and 4,4′-methylenebis (phenyl diisocyanate) as an isocyanate component. ) 500 parts by weight were charged and the temperature was raised to 70 ° C for 5
The reaction was carried out for a time to obtain a polyurethane diisocyanate in which the number of functional groups of the isocyanate group is substantially 2. Furthermore, after that, 60 parts by weight of polypropylene glycol (molecular weight 300, trifunctional) is added as a chain extender, and the temperature is increased to 70 ° C.
The reaction was carried out at the temperature of 5 hours, and finally, 365 parts by weight of ethyl acetate was added as a solvent component to obtain a polyurethane polyisocyanate ethyl acetate solution. This is referred to as curing agent A.
To 100 parts by weight of this curing agent A, 100 parts by weight of a separately prepared polyurethane polyol (trade name; Seika Bond A150, product of Dainichi Seika Kogyo Co., Ltd., viscosity 2700 cps / 25 ° C., hydroxyl value 16) was mixed to obtain an adhesive composition. It was Tables 2 and 3 show the storage stability, the viscosity, the degree of turbidity of the solution, the change over time of each of the obtained curing agents A, and the adhesive strength of the resulting adhesive composition.

Examples 2-3, Comparative Examples 1-6 Curing of Examples 2-3 and Comparative Examples 1-6 in the same manner as in Example 1 except that the polyol component, isocyanate component and chain extender component shown in Table 1 were used. Agent B to curing agent I were obtained. Separately prepared polyurethane polyol (trade name; Seika Bond A150, product of Dainichiseika Chemicals Co., Ltd., viscosity 2700 cps / 25 ° C., hydroxyl value 16) in 100 parts by weight of each obtained curing agent 1
An adhesive composition was obtained by blending 100 parts by weight. Tables 2 and 3 show the storage stability, the viscosity, the degree of turbidity of the solutions, the respective temporal changes of the obtained curing agents B to I, and the adhesive strength of the adhesive compositions.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

Storage conditions of curing agent: left at room temperature in a metal can with a tightly sealed container Solution condition: good ○ ← △ → × poor (generation of turbidity, deterioration of fluidity, etc.)

[0016]

[Table 4]

Adhesion conditions Adherend biaxially oriented polypropylene film manufactured by Nimura Chemical Co., Ltd.
FOR # 20 unstretched polypropylene film manufactured by Nimura Chemical Co., Ltd.
FEK-2 # 40 Adhesives Adhesive Compositions of Examples and Comparative Examples Mixing a main agent and a curing agent in a ratio of 1 to 1 Coating Biaxially oriented polypropylene film side Drying 95 ° C 3 seconds Warm air pressure bonding 3kg / cm ² 1 second 25 ° C Aging 40 ° C. for 48 hours ・ Adhesive strength measurement conditions According to JIS K-6854, tensile speed 300 mm /
min, 15mm width

[0018]

The adhesive composition of the present invention has an extremely small increase in viscosity of the curing agent used during storage,
Further, even when stored for a long period of time, turbidity hardly occurs and the stability of the solution is excellent. Therefore, the workability of the adhesive is extremely good, and it is useful as an adhesive for composite laminating and the like.

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[Procedure amendment]

[Submission date] July 22, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 A flask equipped with a nitrogen inlet tube, a thermometer, a stirrer and a distillation tube was charged with 700 parts by weight of polypropylene glycol (molecular weight about 700, bifunctional) as a polyol component and 4,4′-methylenebis (phenyl diisocyanate) as an isocyanate component. ) 500 parts by weight were charged and reacted at a temperature of 70 ° C. for 5 hours to obtain a polyurethane diisocyanate substantially having 2 functional groups of isocyanate groups. Furthermore, after that, 60 parts by weight of polypropylene glycol (molecular weight 300, trifunctional) is added as a chain extender, and the temperature is increased to 70 ° C.
The reaction was carried out at the temperature of 5 hours, and finally, 315 parts by weight of ethyl acetate was added as a solvent component to obtain a polyurethane polyisocyanate ethyl acetate solution. This is referred to as curing agent A.
To 100 parts by weight of this curing agent A, 100 parts by weight of a separately prepared polyurethane polyol (trade name; Seika Bond A150, product of Dainichi Seika Kogyo Co., Ltd., viscosity 2700 cps / 25 ° C., hydroxyl value 16) was mixed to obtain an adhesive composition. It was Tables 2 and 3 show the storage stability, the viscosity, the degree of turbidity of the solution, the change over time of each of the obtained curing agents A, and the adhesive strength of the resulting adhesive composition.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

[Table 1]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

[0013]

[Table 2]

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016]

[Table 4]

Claims (4)

[Claims] 1. A two-component curable polyurethane adhesive composition comprising a main component containing polyurethane polyol as a main component and a curing agent containing polyurethane polyisocyanate as a main component, wherein the polyurethane polyisocyanate is a diol having a hydroxyl functional group of 2. And a polyurethane polyisocyanate obtained by chain extending a polyurethane diisocyanate having substantially 2 isocyanate functional groups obtained from a diisocyanate having 2 isocyanate functional groups with a polyol having 3 or more hydroxyl functional groups. An adhesive composition characterized by being used. 2. The adhesive composition according to claim 1, which contains an organic solvent. 3. A viscosity of a polyurethane polyol (main agent) to a polyurethane polyisocyanate (curing agent) [cps /
25 ° C.] ratio is 1: 3 to 3: 1. 4. The mixing ratio of polyurethane polyol (main agent) to polyurethane polyisocyanate (curing agent) is 1:
The adhesive composition according to claim 1, which is 3 to 3: 1.