JP2003213239A - Polyurethane adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyurethane adhesive having transparency, exhibiting no shrinkage caused by crystallization, scarcely growing molds, useful for adhering and laminating a composite multilayered film, and having excellent adhesion. <P>SOLUTION: This polyurethane adhesive contains a polyurethane which is obtained by reacting a polyester polyol with an organic polyisocyanete as a resin component, wherein the polyester polyol is obtained by polycondensing 2-butyl-2-ethyl-1,3-propanediol (BEPD) with a multivalent carboxylic acid, or polycondensing the BEPD and a polyol other than the BEPD with the multivalent carboxylic acid. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to 2-butyl-2-
The present invention relates to a polyurethane adhesive containing a polyurethane obtained by reacting a polyester polyol of a diol containing ethyl-1,3-propanediol and a polyvalent carboxylic acid with an organic polyisocyanate as a resin component. The polyurethane adhesive of the present invention is particularly suitable for adhering composite multilayer films.

[0002]

2. Description of the Related Art Generally, polyester-based polyurethane adhesives are superior in adhesive strength to polyether-based polyurethane adhesives, but have a problem that they are inferior in hydrolysis resistance and mold resistance. Further, since the polyester-based polyurethane adhesive has crystallinity, there is a problem of whitening and shrinkage due to crystallization after laminating, so that its use is greatly limited.

[0003]

In recent years, for example, as packaging materials for foods, cellophane, polyethylene, polypropylene, nylon, polyester, vinyl chloride, EVAL (trade name of saponified ethylene-vinyl acetate copolymer), Surlyn ( A multi-layer composite film in which a plastic film such as a metal salt of ethylene- (meth) acrylic acid copolymer) or a metal foil such as an aluminum foil is laminated in several layers has been developed and widely used. Polyurethane-based adhesives are often used for bonding, but it has been pointed out that the adhesive strength is not always satisfactory.

In general, a polycondensation type polyester polyol, for example, a polyurethane adhesive obtained from an adipate type adhesive adheres to various adherends as compared with a polyurethane adhesive obtained from an addition polymerization type polycaprolactone type polyester polyol. Inferior in sex.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to solve the drawbacks of the prior art, and as a result, diol containing 2-butyl-2-ethyl-1,3-propanediol and polyvalent carboxylic acid. A polyurethane adhesive containing a polyurethane (A) obtained by reacting a polyester polyol with an organic polyisocyanate as a resin component has an extremely improved adhesive force, has no problems such as whitening and shrinkage due to crystallization, and is resistant to hydrolysis. The inventors have found that degradability and mold resistance are improved to the extent that they cannot be considered with conventional polyester-based polyurethanes, and that transparency is also very good, and the present invention has been completed.

That is, the first aspect of the present invention is 2-butyl-2.
-Ethyl-1,3-propanediol (BEPD) and polyester polyol (a) obtained from other polyol (f) optionally added and polyvalent carboxylic acid (e), and organic polyisocyanate (c) Provided is a polyurethane adhesive containing a reacted polyurethane (A) as a resin component. The second aspect of the present invention is to mix the polyester polyol (a) with at least one or more chain extenders (d) and / or other polyols (g), and to react them with the organic polyisocyanate (c). There is provided a polyurethane adhesive according to the first aspect of the present invention, which comprises the resulting polyurethane (A) as a resin component. The third aspect of the present invention is BE
The polyurethane adhesive according to the first or second aspect of the present invention is characterized in that PD accounts for at least 20% by weight of the total polyol used in the polyurethane (A). A fourth aspect of the present invention is that the polyurethane (A) has a ratio of NCO of the organic polyisocyanate (c) to total active hydrogen (total of OH and NH) used in the polyurethane (A) of 1.1 to 3. The polyurethane adhesive according to any one of the first to third aspects of the present invention, which is an active hydrogen-terminated polyurethane prepolymer obtained by reacting with 0, and is mixed with an isocyanate group-containing curing agent. The fifth aspect of the present invention is
Polyurethane (A) is an organic polyisocyanate (c)
NCO-terminated polyurethane obtained by reacting the NCO and the total active hydrogen (total of OH and NH) used in the polyurethane (A) (active hydrogen / NCO equivalent ratio) of 0.3 to 0.9 A polyurethane adhesive according to any one of the first to third aspects of the present invention, which is a prepolymer and is mixed with an active hydrogen-containing curing agent. A sixth aspect of the present invention is that the polyurethane (A) is an organic polyisocyanate (c) N
Total active hydrogen (O) used for CO and polyurethane (A)
Ratio of H and NH) (active hydrogen / NCO equivalent ratio)
Is a NCO-terminated polyurethane prepolymer obtained by reacting with 0.3 to 0.9, which reacts with moisture or active hydrogen groups of the material at the time of adhesion to cure.
The polyurethane adhesive according to any one of 1 to 3 is provided.
A seventh aspect of the present invention is that the polyurethane (A) has a ratio (active hydrogen / NCO equivalent ratio) of NCO of the organic polyisocyanate (c) and total active hydrogen (total of OH and NH) used for the polyurethane (A). Is a polyurethane obtained by reacting 1.0) to 1.1, and the polyurethane adhesive according to any one of the first to third aspects of the present invention is obtained by dissolving the polyurethane in a solvent. In the eighth aspect of the present invention, the ratio (active hydrogen / NCO equivalent ratio) of NCO of the organic polyisocyanate (c) and total active hydrogen (total of OH and NH) used in the polyurethane (A) at the time of adhesion is 0. The polyurethane adhesive according to any one of the first to third aspects of the present invention, which is made into polyurethane by mixing and reacting with each other in the range of 0.9 to 1.1. The ninth aspect of the present invention is
There is provided a polyurethane adhesive according to any one of the first to eighth aspects of the present invention, which is used for bonding or laminating a composite multilayer film.

[0007]

DETAILED DESCRIPTION OF THE INVENTION Polyester Polyol (a) Polyester polyol (a) comprises 2-butyl-2-ethyl-1,3-propanediol (BEPD) and optionally other polyol (f). It is obtained from the polycarboxylic acid (e).

2-Butyl-2-ethyl-1,3-propanediol (BEPD) 2-Butyl-2-ethyl-1,3-propanediol (BEPD) is a diol having an ethyl group and a butyl group at the 2-position. Therefore, the polyester polyol (a) using it is amorphous.

Polyvalent carboxylic acid (e) In the present invention, as the polycarboxylic acid used in the reaction with BEPD, adipic acid, succinic acid, malonic acid, suberic acid, glutaric acid, pimelic acid, sebacic acid, Saturated aliphatic polycarboxylic acids such as azelaic acid, aromatic polycarboxylic acids such as phthalic acid, terephthalic acid and isophthalic acid, unsaturated aliphatic polycarboxylic acids such as maleic acid, fumaric acid and itaconic acid, cyclohexanedicarboxylic acid Examples thereof include saturated alicyclic polyvalent carboxylic acids such as acids, and one or more of these polyvalent carboxylic acids can be used in combination. Among these polyvalent carboxylic acids, saturated aliphatic dicarboxylic acids of adipic acid, succinic acid and malonic acid are particularly preferable because a polyurethane adhesive having a high flexibility can be obtained. In the present invention, BEPD may be subjected to polycondensation reaction with dicarboxylic acid or dicarboxylic acid chloride, or BEPD or dicarboxylic acid may be esterified and subjected to transesterification reaction.

Other Polyols (f) In the present invention, the other polyols (f) which are optionally added to BEPD in the production of the polyester polyol (a) are those having two or more hydroxyl groups. Any material may be used, and typically, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-bis (β-hydroxyethoxy) benzene, 1 , 4-cyclohexanediol, bis (β-hydroxyethyl) terephthalate, xylene glycol and other diols; trimethylolpropane or glycerin and other triols; polycaprolactone polyol,
Polyester polyols such as polyethylene adipate and polybutylene adipate; and polyether polyols such as polypropylene glycol, polytetramethylene glycol, and polyethylene glycol. In the polyester polyol (a),
The weight ratio of BEPD in the total of BEPD and other polyol (f) is 20 to 100% by weight, preferably 25% by weight or more. If the ratio of BEPD in the polyester polyol (a) is less than the above range, the polyester polyol tends to have crystallinity, and the polyurethane adhesive obtained by using the polyester polyol (a) is unfavorable because of poor adhesiveness and flexibility.

In the present invention, the number average molecular weight of the polyester polyol (a) is preferably 300 to 100,000. Furthermore, 500-10,000 are preferable. When the number average molecular weight is less than 300, the obtained adhesive becomes hard, and in particular, when it is used for a multilayer composite film or a laminate, flexibility is lost and a problem occurs. Also,
If the number average molecular weight exceeds 100,000, the viscosity becomes high and handling becomes difficult.

The polyester polyol (a) used in the present invention is produced by polycondensing the above-mentioned dicarboxylic acid component and diol component by a conventionally known transesterification reaction, direct esterification reaction or the like. In that case, the polycondensation reaction can be carried out in the presence of a titanium-based or tin-based polycondensation catalyst. When a titanium-based polycondensation catalyst is used, the polyester polyol (a) is used after completion of the polycondensation reaction. It is preferable to deactivate the titanium-based polycondensation catalyst contained in.

When a titanium-based polycondensation catalyst is used in the production of the polyester polyol (a), any titanium-based polycondensation catalyst conventionally used in the production of polyester polyols can be used without any particular limitation. Examples of preferable titanium-based polycondensation catalysts include titanic acid, tetraalkoxytitanium compounds, titanium acylate compounds, and titanium chelate compounds. More specifically, tetraisopropyl titanate,
Tetraalkoxy titanium compounds such as tetra-n-butyl titanate, tetra-2-ethylhexyl titanate and tetrastearyl titanate, titanium acylate compounds such as polyhydroxy titanium stearate and polyisopropoxy titanium stearate, titanium acetyl acetate, triethanolamine Examples thereof include titanium chelate compounds such as titanate, titanium ammonium lactate, titanium ethyl lactate, and titanium octylene glycolate.

The amount of the titanium-based polycondensation catalyst used is not particularly limited, but is generally about 0.1 to 5 relative to the total weight of the reaction components for forming the polyester polyol (a).
It is preferably 0 ppm, more preferably about 1 to 30 ppm.

As a method for deactivating the titanium-based polycondensation catalyst contained in the polyester polyol (a), for example, the polyester polyol obtained by the completion of the esterification reaction is brought into contact with water under heating to deactivate it. Phosphoric acid, phosphoric acid ester, phosphorous acid,
Examples thereof include a method of treating with a phosphorus compound such as a phosphite. When the titanium-based polycondensation catalyst is contacted with water to deactivate it, 1% by weight or more of water is added to the polyester polyol obtained by the esterification reaction, and the temperature is 70 to 150 ° C, preferably 90 to 130 ° C. It is good to heat for 1-3 hours. The deactivation treatment of the titanium-based polycondensation catalyst may be performed under normal pressure or under pressure. It is desirable to depressurize the system after deactivating the titanium-based polycondensation catalyst because the water used for deactivation can be removed.

Organic polyisocyanate (c) Examples of the organic polyisocyanate (c) used in the polyurethane adhesive of the present invention include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, and 2,6. -Tolylene diisocyanate, tolylene diisocyanate (mixture of 2,6- and 2,4-isomers), p-phenylene diisocyanate, m-phenylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3'-dichloro-4 Aromatic diisocyanates such as 4'-diphenylmethane diisocyanate and xylylene diisocyanate; lysine diisocyanate; hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4
And aliphatic or alicyclic diisocyanates such as trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate and hydrogenated xylylene diisocyanate.

Chain extender (d) In the present invention, the chain extender (d) used in the present invention as a mixture with the polyester polyol (a) at the time of production of the polyurethane (A) has been conventionally used for production of ordinary polyurethanes. Any of the above compounds can be used and is not particularly limited, but it is preferable to use a low molecular weight compound having a molecular weight of 300 or less and having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule. For example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-
Hydroxyethoxy) benzene, 1,4-cyclohexanediol, bis (β-hydroxyethyl) terephthalate, xylylene glycol and other diols, hydrazine, ethylenediamine, propylenediamine, xylenediamine, isophoronediamine, piperazine, piperazine derivatives, phenylenediamine , Diamines such as tolylenediamine, xylylenediamine, adipic acid dihydrazide, and isophthalic acid dihydrazide, and amino alcohols such as aminoethyl alcohol and aminopropyl alcohol. One or more of these may be used. It Further, if necessary, a monohydric low molecular weight alcohol, a low molecular weight amine or the like can be used as a modifier.

Other Polyols (g) In the present invention, at least one or more other polyols (g) to be used in combination with the polyester polyol (a) during the production of the polyurethane (A) are other than those described above. Examples thereof include polyol (f).

BEPD, which is an essential component of the present invention, includes all polyols used in polyurethane (A) (that is, BEPD, other polyols (f), the polyol component in the chain extender (d), and other components). Account for at least 20% by weight, based on the total weight of polyol (g). When the amount of BEPD used is less than 20% by weight, excellent adhesiveness of the resulting polyurethane adhesive cannot be obtained, crystallinity appears, and shrinkage and whitening occur.

The method for producing the polyurethane (A) is not particularly limited, and a known urethanization reaction technique is used. Depending on the application, the polyurethane (A) may be a prepolymer having an isocyanate group, a prepolymer having an active hydrogen group, or a high molecular weight thermoplastic polyurethane.

The polyurethane adhesive of the present invention is classified as follows according to its use. (1) NCO-terminated prepolymer + active hydrogen-containing curing agent (polyol and / or polyamine) → reaction curing. (2) Active hydrogen-terminated prepolymer + isocyanate group-containing curing agent (polyisocyanate compound or NCO-terminated prepolymer) → reaction curing. (3) NCO-terminated prepolymer + water or active hydrogen of material → reaction curing (moisture curing type). (4) Isocyanate + polyol + chain extender → Synthesis in solvent or resin synthesis followed by dissolution in solvent → coating → drying → reaction curing, or adhesive layer formation by solvent removal. (5) Isocyanate + polyol and / or polyamine mixture → mixing → reaction curing (one-shot type). A solvent may be used for (1) to (4).

The optimum molecular weight can be selected depending on the device used for laminating the composite multilayer films. For example, a mixture of a polyester polyol containing BEPD and optionally a chain extender (d) and / or other polyol (g) is heated to about 40 ° C. to 100 ° C., and then all of these mixtures are mixed. The equivalent ratio of active hydrogen and NCO groups (active hydrogen (H) / NCO equivalent ratio) is 3.0 to 0.
Add a polyisocyanate compound in a ratio of 3 to 50
The reaction is carried out at a temperature of 150 to 150 ° C. H / NCO is 0.3-0.
In the case of 9, a prepolymer having a terminal isocyanate group is obtained. When H / NCO is 1.1 to 3.0, a hydroxyl group-terminated prepolymer is obtained. H / NCO is 0.9-1.
In the case of 1, since a high molecular weight polyurethane is obtained and the viscosity becomes high, the reaction is generally performed in a solvent to obtain a one-component solvent type polyurethane (A) adhesive. The equivalent ratio of active hydrogen and NCO group (active hydrogen / NCO equivalent ratio) is 3.
If it exceeds 0, the proportion of unreacted chain extender, polyol, etc. increases, and the cohesive force of the polyurethane (A) adhesive obtained by curing with a polyisocyanate curing agent decreases,
It is not preferable because tough adhesion cannot be obtained, and the equivalent ratio of active hydrogen and NCO group (active hydrogen / NCO equivalent ratio)
Is less than 0.3, the resulting prepolymer contains a large amount of unreacted isocyanate compound, which is problematic in terms of toxicity. Furthermore, when curing with a curing agent for water or a polyol mixture, a reaction occurs due to excess NCO groups and water, and bubbles are easily generated due to the generation of diacid carbon, which is not preferable.

A preferred method for producing a one-component solvent-type polyurethane (A) adhesive is, for example, a polyester polyol (a) in a suitable solvent and optionally a chain extender (d) and / or it. Other polyols (g)
And excess polyisocyanate compound with active hydrogen and NC
O group equivalent ratio (active hydrogen / NCO equivalent ratio) 1 / 1.5 to
A prepolymer having an isocyanate group at the terminal is reacted (preferably NCO content of 0.
5 to 2%), and then a chain extender dissolved in a solvent is added in 2 to 3 steps to finally add NC.
Adjust the O content to 0-0.1. If necessary, chain stopper (monohydric low molecular weight alcohol or amine compound, etc.)
React with. Furthermore, as a preferable method for producing a one-component solvent-based urethane adhesive, for example, without using a solvent, a polyester polyol (a) and, if necessary, a chain extender (d) and / or it using an extruder or the like can be used. Other than the polyol (g) and the polyisocyanate compound, the equivalent ratio of active hydrogen and NCO groups (active hydrogen / NCO equivalent ratio) is 1.1.
The resulting thermoplastic polyurethane resin is dissolved in a solvent by reacting so as to be / 1 to 1 / 1.1. In the production of these polyurethanes (A), various known catalysts such as tin-based catalysts such as dibutyltin dilaurate and stannous octylate are used, if necessary. Polyurethane (A) has a number average molecular weight (Mn) of 3,000 to 30.
It is preferably in the range of 10,000. When the number average molecular weight is less than 3,000, the polyurethane adhesive has too low a molecular weight to obtain sufficient adhesive strength.
When it exceeds 100,000, the viscosity of the polyurethane (A) solution becomes high, and the workability and coatability deteriorate.

The urethanization reaction can be carried out in various organic solvents or without solvent. For example, in the case of a multilayer film adhesive that requires a high molecular weight to some extent, it is preferable to use a solvent having low toxicity and a low boiling point, and examples thereof include ethyl acetate, methyl ethyl ketone, and acetone.
Toluene, methyl cellosolve, acetate, ethyl erosolve acetate, cyclohexane, methyl isobutyl, ketone, dioxane, cyclohexanone, tetrahydrofuran, dimethylformamide and the like can be mentioned. The amount of the solvent used is 0.5 to 1 with respect to the polyurethane solid content.
4 times by weight is preferable. Further, the solvent that can be used is limited depending on the type of adherend.

In the case of polyurethane adhesive active hydrogen terminated prepolymers, polyisocyanate compounds are used as the isocyanate group-containing curing agent. Examples thereof include polyisocyanates such as adducts of isocyanate with glycerin or trimethylolpropane (for example, Coronate L manufactured by Nippon Polyurethane Co., Ltd.). The polyisocyanates may be used alone or as a mixture. Furthermore, NCO-terminated prepolymers can also be used as curing agents. In the case of a terminal isocyanate group prepolymer, an active hydrogen-containing curing agent is used, and a polyol mixture containing a trifunctional or higher functional polyol or a polyamine-based curing agent is used. Three
As the functional or higher polyol, for example, a propylene oxide adduct of trimethylolpropane (Sanyox GP-600 manufactured by Sanyo Chemical Co., Ltd.), an ε-caprolactone adduct of trimethylolpropane (Placcel 305 manufactured by Daicel Chemical Co., Ltd.) and the like are used. be able to. As the polyamine-based curing agent, conventionally known ones can be used. Further, a catalyst may be added to the polyurethane adhesive in order to accelerate the curing reaction depending on the purpose.

The polyurethane adhesive of the present invention has an adhesive strength comparable to that of a polycaprolactone-based polyurethane adhesive, even though the polyurethane (A) is a polycondensed polyester adhesive. Further, polycaprolactone-based polyester has crystallinity and is solid at room temperature, whereas polyester polyol containing 2-butyl-2-ethyl-1,3-propanediol is liquid at room temperature, and thus is easy to handle. It's easy. The reason why the polyurethane adhesive of the present invention has good adhesiveness is considered to be that the carbon number of the diol constituting the polyester of the polyurethane (A) and that it has two branches of butyl and ethyl. . Polyurethane (A) is a liquid, though it depends on the polyvalent carboxylic acid used for the polyester polyol and the molecular weight, and therefore can be used as a solventless liquid adhesive. Since the polyurethane adhesive used in the present invention has the above-mentioned features, it is suitable for adhering packaging materials such as foods and pharmaceuticals.

[0027]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. Parts and% are parts by weight and% by weight unless otherwise specified.
Indicates. The polyols, polyisocyanates, and chain extenders that are the raw materials for polyurethane used in the examples are indicated by abbreviations, and the relationship between the abbreviations and compounds is as shown in Table 1.

[0028]

[Table 1]

[Example 1] (Synthesis of BEPDHA and polyurethane using the same) 2-Butyl-2-ethyl-1,3-propanediol (BEPD) 333.32 g, 1.6-hexanediol 242.79 g, 563.03 g of adipic acid was placed in a reaction vessel, 0.1 g of zinc acetate was added as a catalyst, and the temperature was adjusted to 1
The esterification reaction was carried out at 80 to 220 ° C. After reacting for about 7 hours until a predetermined amount of water is drained, OH value is 56.4 mg KO
About 1,000 g of adipic acid ester (BEPDHA, molecular weight about 2,000) having a molar ratio of H / g, BEPD and 1,6-hexanediol of 1: 1 was obtained. This BEPDH
A 200 g, MDI 50 g, 1,4-butanediol 9.45 g, and ethyl acetate 650 g were put in a reaction vessel, and 8
The reaction was carried out at 0 ° C. for 4 hours to obtain a hydroxyl-terminated polyretane solution. This polyurethane solution had a hydroxyl value of 2.46 mgKOH / g in terms of solid content and a solid content of about 40%.
Coronate L for 100 parts of this polyurethane solution
5 parts were mixed, diluted with ethyl acetate to a 20% solution, and a laminator was used to obtain a coating amount of 3.0 g / m2.
Polyester film (PET film, Toray, Tetron) and polypropylene film (OPP film,
Toyo Cellophane, surface corona treatment) pasted together 4
After curing and adhering at 0 ° C. for 3 days, the adhesive strength (T type peeling, pulling speed 300 mm / min) and other properties were measured. The results are shown in Table 3.

[Example 2] (Synthesis of BEPDA and polyurethane using it) 536.51 g of BEPD and 463.51 g of adipic acid were placed in a reaction vessel, and 0.1 g of zinc acetate was added as a catalyst.
The esterification reaction was performed at a temperature of 180 to 220 ° C. After reacting for about 7 hours until a certain amount of water is drained, OH value is 56.5 m
gKOH / g, BEPD adipate (BEP
About 1,000 g of DA and a molecular weight of about 2,000 were obtained. This BEPDA 200g, TDI 34.8g, 1,4-
9.45 g of butanediol and 611 g of ethyl acetate were placed in a reaction vessel and reacted at 80 ° C. for 4 hours to obtain a hydroxyl group-terminated polyurethane solution. This polyurethane solution had a hydroxyl value of 2.33 mgKOH / g in terms of solid content and a solid content of about 40%. This polyurethane solution was evaluated in the same manner as in Example 1 and the results are shown in Table 3.

[Example 3 and Comparative Examples 1 to 11] Using the raw materials shown in Table 1, polyurethane adhesives were produced. That is, the polyol, polyisocyanate and chain extender were added to the reactor at the ratio (molar ratio) shown in Table 2,
A polyurethane having terminal hydroxyl groups was obtained in the same manner as in Example 1 such that the solid content was 40% by weight in ethyl acetate. Except for Example 3 and Comparative Example 11, these polyurethanes were very flexible.

Evaluation Method Crystal Whitening: The laminated film after curing at 40 ° C. for 3 days was visually observed for whitening. Crystal shrinkage: It was observed whether or not the laminated film after curing at 40 ° C. for 3 days was wound due to shrinkage. Hydrolysis resistance: The laminated film after curing at 40 ° C. for 3 days was immersed in hot water at 100 ° C. for 30 days, and the presence or absence of peeling of the film was observed. Mold resistance: Aspergillus-sybowl, Aureobasidium, Cladosporiu after laminating film after curing at 40 ° C for 3 days
The sample pieces were allowed to stand for 24 days at 30 ° C. in a mixed medium in which four types of m and Alernaria fungi were mixed at a weight ratio of 25: 25: 25: 25, and the presence or absence of mold was observed. Adhesiveness: The laminated film after curing at 40 ° C. for 3 days was cut into a width of 25 mm, and a T-type peeling test was performed with Tensilon. When the peel strength is 2.0 kg / 25 mm or more, the evaluation is ◎, 1.5 kg / 25 mm or more and 2.0 kg /
○: less than 25 mm, △: 1.0 kg / 25 mm or more and less than 1.5 kg / 25 mm, 1.0 kg / 2
The case of less than 5 mm was evaluated as x. Comprehensive evaluation: A comprehensive evaluation of O was made when the T-type peel strength was 2.0 kg / 25 mm or more, the whitening, crystal shrinkage, and hydrolysis resistance were good even after 30 days, and the mold resistance test was also good. All items except the adhesion test are good, and the T-type peel test strength is 1.5 kg / 25 mm or more and 2.0 kg /
Those having a size of less than 25 mm were evaluated as Δ. If any of the items other than the adhesion test had a problem, the comprehensive evaluation was rated X regardless of the adhesion strength.

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

INDUSTRIAL APPLICABILITY The polyurethane adhesive of the present invention, in which polyurethane as a resin component is an amorphous polymer, has transparency, is free from whitening and shrinkage due to crystallization, and is extremely suitable for a wide range of adherends. Has excellent adhesive strength,
It is also excellent in hydrolysis resistance and mold resistance, and is particularly suitable for adhesion of composite multilayer films.

Claims (9)

[Claims] 1. A polyester polyol (a) obtained from 2-butyl-2-ethyl-1,3-propanediol (BEPD) and another polyol (f) optionally added and a polyvalent carboxylic acid (e). ) And a polyurethane adhesive obtained by reacting an organic polyisocyanate (c) with a polyurethane (A) as a resin component. 2. A polyester polyol (a) is mixed with at least one or more chain extenders (d) and / or other polyols (g) and reacted with an organic polyisocyanate (c). The polyurethane adhesive according to claim 1, wherein the polyurethane (A) is a resin component. 3. The polyurethane adhesive according to claim 1, wherein BEPD accounts for at least 20% by weight of the total polyols used in polyurethane (A). 4. The polyurethane (A) has a ratio of NCO of the organic polyisocyanate (c) to total active hydrogen (total of OH and NH) used in the polyurethane (A) of 1.1.
The polyurethane adhesive according to any one of claims 1 to 3, wherein the polyurethane adhesive is an active hydrogen-terminated polyurethane prepolymer obtained by reacting at 3.0 to 3.0, and an isocyanate group-containing curing agent is added thereto. 5. The polyurethane (A) has a ratio (active hydrogen / NCO equivalent ratio) of NCO of the organic polyisocyanate (c) to all active hydrogen (total of OH and NH) used in the polyurethane (A). The polyurethane adhesive according to any one of claims 1 to 3, which is an NCO-terminated polyurethane prepolymer obtained by reacting at 0.3 to 0.9, and is mixed with an active hydrogen-containing curing agent. 6. The polyurethane (A) has a ratio (active hydrogen / NCO equivalent ratio) of NCO of the organic polyisocyanate (c) and total active hydrogen (total of OH and NH) used in the polyurethane (A). The NCO-terminated polyurethane prepolymer obtained by reacting at 0.3 to 0.9, which reacts with moisture or active hydrogen groups of the material at the time of adhesion and is cured. Polyurethane adhesive. 7. The polyurethane (A) has a ratio (active hydrogen / NCO equivalent ratio) of NCO of the organic polyisocyanate (c) to all active hydrogen (total of OH and NH) used in the polyurethane (A). The polyurethane adhesive according to any one of claims 1 to 3, which is a polyurethane obtained by reacting at 1.0 to 1.1 and is dissolved in a solvent. 8. The ratio of NCO of organic polyisocyanate (c) to total active hydrogen (total of OH and NH) used in polyurethane (A) during bonding (active hydrogen / NC).
The polyurethane adhesive according to any one of claims 1 to 3, wherein the polyurethane adhesive is made into a polyurethane by mixing and reacting it in an O equivalent ratio of 0.9 to 1.1. 9. The polyurethane adhesive according to claim 1, which is used for bonding or laminating a composite multilayer film.