JPH0959587A - Copolyester resin for adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copolyester resin excellent in processability, water resistance and adherability, and useful as a base resin for adhesives. SOLUTION: This copolyester resin with a number-average mol-ecular weight of 5000-50000 is made from (A) an acid component composed of (i) 80-100mol% of an aromatic dicarboxylic acid and (ii) 0-20mol% of a dicarboxylic acid except the component (i) and (B) an alcohol component composed of (i) 0.5-20mol.% of a diol of the formula HO-CH2 -R1 -CH2 -OH [R1 is a >=14C (cyclic) alkylene], (ii) 70-99.5mol% of another diol and (iii) 0-10mol% of a trihydric or polyhydric alcohol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyester resin for adhesives, and more particularly to a copolyester resin which is useful as a base resin for adhesives and has excellent processability, water resistance and adhesion.

[0002]

2. Description of the Related Art Copolyester resins soluble in organic solvents have been used in adhesives because they have a good balance of processability and hardness and excellent adhesion to various plastics and metals. Many are used.

For example, various plastic films such as polyvinyl chloride film and polyester film are used as steel plates,
As an adhesive resin for laminating and adhering to a stainless steel plate, an aluminum plate or the like to obtain a composite plate, an adhesive which is a combination of a copolyester resin and an isocyanate is used.

[0004]

However, since this adhesive has poor water resistance, there is a problem that when a composite plate manufactured using this adhesive is brought into contact with water for a long time, peeling occurs at the bonded portion. In addition, the composite board as described above is often used after being subjected to processing such as bending. However, in such a case, peeling may occur, and improvement in workability of the adhesive is also required. An object of the present invention is to provide a copolymerized polyester resin which is useful as a base resin for adhesives and the like and is excellent in processability, water resistance and adhesion.

[0005]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have used a specific amount of a specific component for an acid component and an alcohol component and have a molecular weight within a specific range. The inventors have found that a copolyester resin can achieve the object, and completed the present invention.

That is, the present invention relates to (A) 80 to 100 mol% of aromatic dicarboxylic acid (a-1) and 0 to 20 mol% of dicarboxylic acid (a-2) other than aromatic dicarboxylic acid.
An acid component consisting of (B) 0.5 to 20 mol% of a diol (b-1) represented by the following general formula (I), another diol (b-2) 70 to 99.5 mol% and a trivalent compound. The above polyhydric alcohol (b-3) is an alcohol component consisting of 0 to 10 mol% and has a number average molecular weight of 5,000 to 50,
It is in the copolyester resin characterized by being 000.

[0007]

Embedded image (In the formula, R ₁ is a linear, branched, or cyclic alkylene group having 14 or more carbon atoms.)

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The acid component (A) used for obtaining the copolyester resin of the present invention contains an aromatic dicarboxylic acid (a-1) as a main component, and if necessary, may be aromatic. Dicarboxylic acids other than aromatic dicarboxylic acids (a-2)
(Hereinafter, abbreviated as other dicarboxylic acid (a-2).) Can be used in combination.

The aromatic dicarboxylic acid (a-1) used as the acid component (A) includes terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid,
2,6-naphthalenedicarboxylic acid, and their acid anhydrides, acid halides, lower alkyl esters and the like. Examples of the lower alkyl ester of the aromatic dicarboxylic acid include esters such as methyl, ethyl, propyl and butyl, and the methyl ester is preferably used in terms of cost and handling. These aromatic dicarboxylic acids (a-1) can be used alone or in combination of two or more.

The other dicarboxylic acid (a-2) used as the acid component (A) is, for example, sebacic acid,
Aliphatic dicarboxylic acids such as succinic acid, maleic acid, fumaric acid, adipic acid and azelaic acid, alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroisophthalic acid and hexahydroterephthalic acid, and acid anhydrides thereof,
Examples thereof include acid halides and lower alkyl esters. These can be used alone or in combination of two or more.

The proportion of the aromatic dicarboxylic acid (a-1) and the other dicarboxylic acid (a-2) in the acid component (A) is 80 to 100 mol% of the aromatic dicarboxylic acid (a-1). Of the dicarboxylic acid (a-2) of 0 to 20 mol% and the amount of the aromatic dicarboxylic acid (a-1) is 80 mol%.
If it is less than 1, the water resistance of the adhesive will decrease.

Next, the alcohol component (B) used to obtain the copolyester resin of the present invention is a diol (b-1) represented by the above general formula (I) and another diol (b-2). And a polyhydric alcohol (b-3) having a valence of 3 or more can be used in combination, if necessary.

The diol (b-1) represented by the above general formula (I) used in the present invention is a component which imparts processability, water resistance and adhesion to the resin, and specific examples thereof include the following general ones. Mention may be made of mixtures of diols of the formulas (II) and (III).

[0014]

Embedded image

[0015]

Embedded image

The diol (b) represented by the above general formula (I)
-1) is 0.5 to 20 mol%, preferably 0.5 to 15 mol%, more preferably 1 in the alcohol component (B).
It is contained in the range of 10 to 10 mol%, and if the content is less than 0.5 mol%, the effect cannot be obtained, and the content is 20 mol%.
If it exceeds, the desired molecular weight cannot be obtained.

The other diol (b-2) used as the alcohol component (B) is, for example, ethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,4. -Butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-
Decanediol, diethylene glycol, triethylene glycol, 2-methyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propane Aliphatic diol such as diol, alicyclic diol such as 1,4-cyclohexanedimethanol, ethylene oxide or propylene oxide adduct of bisphenol A,
Aromatic diols such as ethylene oxide or propylene oxide adducts of bisphenol S, polyethylene glycol, polytetramethylene glycol, polycaprolactone diol having two hydroxyl groups at the ends, for example, Praxel 200 manufactured by Daicel Chemical Industries, Ltd.,
210, 240, 300 etc. are mentioned. These can be used alone or in combination of two or more.

The other diol (b-2) is 70 to 99.5 mol%, preferably 85 to 9 in the alcohol component (B).
It is contained in an amount of 9.5 mol%, more preferably 80 to 99 mol%. When the content exceeds 99.5 mol%, the processability, water resistance and adhesion of the resin become insufficient, and 7
If it is less than 0 mol%, the productivity of the resin will decrease.

The trihydric or higher polyhydric alcohol (b-3) used in the present invention is a component that imparts processability to the resin, and is used as necessary. Examples of the trihydric or higher polyhydric alcohol used include, for example, sorbitol, 1,2,3,6-hexanetetralol, 1,4-
Sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4
-Butanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, or a hydroxyl group at the terminal 3 Individual polycaprolactone triol, for example, Praxel 303, 305, 306, 308, 312, 320 manufactured by Daicel Chemical Industries, Ltd.
Etc., such as polytetramethylene glycol having three hydroxyl groups at the end, for example, PTG-30 manufactured by Hodogaya Chemical Co., Ltd.
00TF etc. are mentioned. These can be used alone or in combination of two or more.

The trihydric or higher polyhydric alcohol (b-3) is
0 to 10 mol%, preferably 0 to 0 mol% in the alcohol component (B)
-8 mol%, more preferably 0-6 mol% is contained, and when the content exceeds 10 mol%, the resin gels and becomes difficult to dissolve in the solvent.

In the copolyester resin for adhesives of the present invention having the above constitution, the number average molecular weight is 5,0.
00 to 50,000, preferably 6,000 to 40,0
It is important that the number average molecular weight is less than 5,000, and if the number average molecular weight is less than 5,000, the cohesive strength of the resin is weak and sufficient adhesive strength cannot be obtained. When used as a base resin for an adhesive when it exceeds 000, the viscosity becomes high and handling becomes difficult,
In addition, when it is used for a steel sheet, the wetting of the steel sheet becomes insufficient and the adhesive strength becomes insufficient.

The method for producing the copolyester resin of the present invention is not particularly limited, but known polymerization methods as described below can be applied. For example, first, the monomer is charged into a reaction kettle and heated to raise the temperature to carry out an esterification reaction or a transesterification reaction to remove water or alcohol produced in this reaction. At this time, if necessary, an esterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, magnesium acetate, manganese acetate, and zinc acetate, which is used in a normal esterification reaction or transesterification reaction, can be used.

Next, a polycondensation reaction is subsequently carried out. At this time, polymerization is carried out under a vacuum of 150 mmHg or less while distilling and removing the diol component. In the polymerization, known polymerization catalysts such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, and germanium dioxide can be used. Further, the polymerization temperature and the amount of the catalyst are not particularly limited, and may be arbitrarily set as needed.

The copolyester resin obtained by the present invention is particularly useful as a base resin for adhesives, and the copolyester resin of the present invention is usually used by dissolving it in an organic solvent. Organic solvents that can be used include benzene, toluene, xylene, mineral terpenes, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, methyl cellosolve,
Various solvents such as butyl cellosolve, cellosolve acetate, isophorone, methanol, ethanol, butanol, Solvesso 100, 150 can be used, but one or a mixture of two or more of them may be selected in consideration of solubility and evaporation rate. It can be selected and used.

Further, a crosslinking agent such as a melamine resin, an isocyanate compound or a block isocyanate compound, an epoxy resin, a phenol resin, a urethane resin, a vinyl chloride resin, a fibrin resin, etc. may be blended according to the purpose and the required performance. Can be used.

Also, inorganic and organic pigments such as titanium oxide, carbon black and phthalocyanine, rust preventive pigments such as strontium chromate and zinc chromate, surface smoothing agents, antifoaming agents, and coupling agents such as titanium and silicon based. Can also be blended.

[0027]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The performance evaluation in the following examples and comparative examples was performed using the following method.

(1) Resin Composition Analysis Composition analysis was carried out by NMR.

(2) Number average molecular weight The number average molecular weight in terms of GPC polystyrene was determined.

(3) Initial peeling strength: The adhered steel plate was cut into a width of 2 cm, and the 180-degree peeling strength was measured.

(4) Peeling strength after water resistance: The adhered steel plate was cut into a width of 2 cm and immersed in boiling water at 100 ° C. for 2 hours, and then the 180-degree peeling strength was measured.

(5) Adhesion workability: The polyvinyl chloride film surface of the adhered steel sheet was cut and bent with a bending tester of 2 mmφ, and the peeling state of the sheet surface was evaluated by the following 5 points. 5: No peeling 4: Slight peeling 3: Half peeling 2: Most peeling 1: Full peeling

The abbreviations in the table represent the following compounds. IPA: isophthalic acid TPA: terephthalic acid ADA: adipic acid EG: ethylene glycol NPG: neopentyl glycol CHDM: 1,4-cyclohexanedimethanol TMP: trimethylolpropane praxel 308: caprolactone triol, manufactured by Daicel Kagaku KK Plaxel 303: Caprolactone triol, manufactured by Daicel Chemical Industries, Ltd. Diol b-1: Mixture of diols represented by the above general formulas (II) and (III) (composition; general formula (II) / (III) =
75/25 (weight ratio)).

Example 1 2.21 mol parts of isophthalic acid, 2.21 mol parts of terephthalic acid, 2.47 mol parts of ethylene glycol, 2.88 mol parts of neopentyl glycol and 0.001 mol parts of zinc acetate were reacted. The mixture was charged into a container and the esterification reaction was carried out while distilling water at an internal temperature of 230 to 265 ° C. After confirming that the esterification reaction product became transparent, 0.11 mol part of diol b-1 and 0.0016 mol part of antimony trioxide were added, and the internal temperature was controlled at 260 to 265 ° C. 30 inside
The pressure was reduced to 1.0 mmHg over minutes, and the condensation reaction was carried out for 1.5 hours while distilling an excess glycol component. Table 1 shows the measurement results of the resin composition and the number average molecular weight of the obtained copolyester resin A-1.

Then, this copolymerized polyester resin A-
1 was dissolved in a solvent of xylene / cyclohexanone = 80/20 (weight ratio) so that the solid content was 40%, and the obtained resin solution was dissolved in Coronate L (Nippon Polyurethane Co., Ltd.).
Made of polyisocyanate / copolymerized polyester resin /
After compounding so that the ratio of polyisocyanate is 100/1 (solid content ratio), the chemical conversion treated steel plate (Bondelite # 3
900, manufactured by Nippon Test Panel Co., Ltd.) so as to have a film thickness of 4 μm, heat-dried at a plate temperature of 160 ° C., and then a vinyl chloride sheet was attached and then cooled to prepare an evaluation sample. Table 2 shows the evaluation results of the adhesive performance.

Examples 2 to 4 Copolymerization polyester resins A-2 to A-4 were obtained in the same manner as in Example 1 except that the composition for polymerization was changed as shown in Table 1. Table 1 shows the composition analysis results and the number average molecular weight measurement results of the copolymerized polyester resins A-2 to A-4.

Next, the above-mentioned copolymerized polyester resin A-
Samples for evaluation were prepared by using 2 to A-4 in the same manner as in Example 1 and evaluated. Table 2 shows the evaluation results.

[Comparative Examples 1 to 4] Copolymerized polyester resins A-5 to A-8 were obtained in the same manner as in Example 1 except that the composition for polymerization was as shown in Table 1. However, the copolyester resin A-7 was gelated during the production and could not be taken out from the reactor. Table 1 shows the composition analysis results and the number average molecular weight measurement results of the obtained copolyester resins A-5, A-6, and A-8.

Next, the above-mentioned copolymerized polyester resin A-
Samples for evaluation were prepared and evaluated in the same manner as in Example 1 using 5, A-6 and A-8. Table 2 shows the evaluation results.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

The copolyester resin for adhesives of the present invention is excellent in processability, water resistance and adhesion and is industrially very useful.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masamitsu Ito 4-60, Sunadabashi, Higashi-ku, Nagoya, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (1)

[Claims] (A) Aromatic dicarboxylic acid (a-1) 8
An acid component consisting of 0 to 100 mol% and 0 to 20 mol% of a dicarboxylic acid (a-2) other than the aromatic dicarboxylic acid;
(B) A diol (b-1) represented by the following general formula (I)
0.5-20 mol%, other diol (b-2) 70-9
9.5 mol% and a polyhydric alcohol having 3 or more valences (b-
3) A copolyester resin for adhesives, which comprises an alcohol component consisting of 0 to 10 mol% and has a number average molecular weight of 5,000 to 50,000. Embedded image (In the formula, R ₁ is a linear, branched, or cyclic alkylene group having 14 or more carbon atoms.)