KR930009216B1 - Adhesive compositions - Google Patents

Abstract

This is a new adhesive composition for textile, plastics, rubber, paper, wood, et al, especially for adhesion ones with different surface property. The adhesive composition is composed of adhesive resins of high melting pt. and of low melting pt. Pref. the adhesive resin of high melting pt. is polyethylene terephthalate copolymer and its crystal melting pt. is 130-200 deg.C ; and the low one is poly butylene terephthalate and its melting pt. 50-120 deg.C. Mixing ratio of high and low one lies on 95:5-20:80. Pref. the adhesive resin includes terephthalic acid, isophthalic acid or their low alkyl ester as acid component; C6-C12 fatty acid dicarboxylate or its low alkyl ester; above 50 wt.% 1,4-butanediol as glycol comp.; and selected one from ethylene glycol, 1,2- or 1,3-propylene glycol, 1,6-hexanediol, and n- pentyl glycol.

Description

Adhesive Resin Composition

The present invention relates to an adhesive resin composition, and more particularly to an adhesive resin composition suitable for use in bonding fibers, plastics, rubber, paper, wood, etc., in particular based on polyethylene terephthalate or polybutylene terephthalate Co-polyester-based hot-melt adhesive formed by mixing a high melting point resin resin and a low melting point adhesive resin based on polybutylene terephthalate, and exhibiting excellent adhesion to adherends having different surface properties. It relates to a resin composition.

Polyester-based adhesives can be classified into various fields depending on the method of use, but is usually inserted in the form of a fine powder, film, fibers, etc., between the adherents and activated as heat, not an organic solvent. It is classified into the hot-melt type to be bonded and the solvent type to be used by dissolving or dispersing in an organic solvent. However, in recent years, the demand for hot-melt type, which has no pollution by solvent, can simplify and speed up the process, and reduce energy consumption rate and cost, has been increased in recent years. It is widely applied to the adhesion of shoes products.

However, the polyester-based adhesives as described above are widely used in fabrics, films, etc. because of their excellent mechanical properties and resistance to chemicals, but are high in padding products due to their high melting point and high crystallinity due to their molecular structure. There is a drawback that requires temperature and pressure.

In order to solve this drawback, since the late 1960's, the method of using such a copolyester as a binder by copolymerizing by adding a component which can lower the melting point of the polymer into the polyester chain has been proposed.

For example, U.S. Patent No. 4,129,675 proposes a method for producing low melting polyester using terephthalic acid and isophthalic acid, but the adhesive by this method is economically disadvantageous because it is heat-sealed at a high temperature of 190 ° C or higher. In addition, the adhesive according to US Pat. No. 4,065,439, which manufactures low melting point polyesters using terephthalic acid, isophthalic acid, aliphatic dicarboxylic acid and ethylene glycol and neopentyl glycol, has a melting point of 45-60 ° C., which is too low. Not only impossible to use, even if the ambient temperature rises only slightly, there is a disadvantage that the adhesive surface easily falls.

On the other hand, U.S. Patent No. 3,232,813 discloses a technique for copolymerizing terephthalic acid, isophthalic acid, 1,4-butanediol and the like to prepare a powdery adhesive having a melting point of 80 ° C to 200 ° C to be used for bonding fibers, leather, plastics, and the like. It is proposed. However, in this patent technology, since polybutylene terephthalate is a technique in which isophthalic acid is copolymerized to introduce a refraction into the chain to reduce the crystal melting point, the adhesive itself is poor in heat stability and glass. Due to the high transition temperature, the resistance to shock and bending is poor. In the US Patent No. 3,421,974, the copolymer polyester adhesive resin which added ACYCLIC ACID, the aliphatic dicarboxylic acid in US Pat. No. 3,436,301, and terephthalic acid in the form of hydrogen was added in US Pat. It is proposed.

However, such adhesives can be classified into two types according to crystal melting point or glass transition temperature, and one of them has a crystal melting point of about 130 ° C. or higher and a glass transition temperature of room temperature or higher, and hardness at room temperature. The branch is a high melting point adhesive resin, and another is classified as a low melting point adhesive resin having a melting point of 120 ° C. or lower and a glass transition temperature of room temperature or lower and exhibiting rubbery behavior at room temperature. Adhesive resin of high melting point has a large surface roughness, specific surface area and irregular surface among various adherends, and it is useful for adhesion of wood, textile, leather products, paper, etc., which requires a lot of mechanical adhesion among the adhesion mechanisms. Low-melting adhesive resin with excellent adhesion shows good adhesion to metals, glass and plastic products with relatively smooth surfaces.

Based on the above characteristics, in the present invention, an adhesive resin composition obtained by mixing a high melting point adhesive resin and a low melting point adhesive resin in a predetermined ratio so as to exert excellent adhesion to adherends having different surface properties. I would like to propose.

That is, an object of the present invention is to provide an adhesive resin composition suitable for adhesion of adherends having different surface properties.

In order to achieve the above object, the present invention provides an adhesive resin composition containing a high melting point adhesive resin and a low melting point adhesive resin in a ratio of 95: 5 to 20:80 and more preferably 60:40 to 20:80.

At this time, when the content of the low-melting-point adhesive resin is less than 5% by weight, as shown in the present invention, the improvement in the adhesive strength expected for the adhesion of the adherends having different surface properties is not seen, and the content is 80% by weight. If it is more than%, the properties of the high melting point adhesive resin are lost, and the adhesion strength with the rough surface of the adherend is reduced, so that it is difficult to expect the improvement of the adhesive strength. The crystal melting point of the high melting point adhesive resin used in the present invention is about 130 ~ 200 ℃, more preferably 140 ℃ ~ 190 ℃, the defect melting point of the low melting adhesive resin is about 50 ~ 120 ℃, more preferably 60 to 110 degreeC is suitable. If the melting point of the high-melting-point adhesive resin is less than 130 ° C, the glass transition temperature of the final adhesive resin composition is lowered, thereby reducing the morphological holding force at room temperature. As a result, even if the ambient temperature rises only slightly, the adhesive is activated and the surface between the adhesive surface and the adherend is reduced. It is easy to break the mechanical bonds, and the adhesive force decreases. If the melting point is higher than 200 ° C, high temperature of 200 ° C or more is required at the time of bonding, which is economically disadvantageous and damage to the adherend due to high heat of adhesion. This may occur. On the other hand, when the crystal melting point of the low-melting-point adhesive resin is less than 50 ℃, it is too flexible even at room temperature and phase separation with the high-melting-point adhesive resin reduces the cohesive strength of the adhesive to the adhesive surface, which may reduce the adhesive strength. If the temperature is higher than 120 ° C, the property of the low melting point adhesive resin is lost, and there is no adhesive component that maintains the bond to the adherend having a smooth surface in the entire adhesive component, thereby providing excellent adhesion to the adherend having the smooth surface. You cannot expect it.

The present invention is described in more detail as follows.

The present invention provides a copolyester-based adhesive resin composition obtained by mixing a high melting point adhesive resin and a low melting point adhesive resin at a predetermined ratio in order to exhibit excellent adhesion to two or more adherends having different surface properties. .

The high-melting-point adhesive resin used in the present invention includes terephthalic acid, isophthalic acid or lower alkyl ester compounds thereof as acid components, and in addition, 6 to 12 carbon atoms which may be represented by HOOC- (CH ₂ ) n -COOH. Any one selected from individual aliphatic dicarboxylic acids or lower alkyl esters thereof or mixtures thereof may be used, and the glycol component may be ethylene glycol, 1,6-hexanediol, 1,4-butanediol, 1,2 Or 1,3-propylene glycol, neopentyl glycol, or a mixture thereof. A stabilizer, a catalyst, etc. can be added to these main raw materials as needed, and can be used.

On the other hand, low-melting-point adhesive resin and / or a high-melting-point adhesive resin used in the present invention, an acid represented by terephthalic acid, isophthalic acid, or n-COOH include a lower alkyl esterified, and in addition HOOC- (CH ₂₎ Any one selected from aliphatic dicarboxylic acids having 6 to 12 carbon atoms, alicyclic dicarboxylic acids or lower alkyl ester compounds thereof or mixtures thereof may be used, and as the glycol component, essentially 1 , 4-butanediol, and any one or mixture thereof selected from ethylene glycol, 1,6-hexanediol, 1,2 or 1,3-propylene glycol, neopentyl glycol, cyclohexanedimethanol Can be prepared. Moreover, a stabilizer, a catalyst, etc. can be added to these main raw materials as needed.

As described above, the high-melting point adhesive resin and the low-melting point adhesive resin constituting the copolyester-based adhesive resin composition usable in the present invention can be manufactured under conventional polyester reactor conditions and conditions, and the method used in the present invention As follows. First, in manufacturing a high melting point adhesive resin, a raw material component for preparing a high melting point adhesive resin, various stabilizers, a catalyst, and the like are added to a conventional polyester reaction tube, and the temperature of the reaction tube is heated from room temperature to 1.5 to 3.0. The oligomer is manufactured by stirring reaction, heating up at 160-260 degreeC only in time.

At this time, the reaction is carried out while flowing out low-molecular-weight condensation products such as water or methanol produced in the transesterification reaction, and if the condensation product continues to flow out, while maintaining the temperature at 160 ~ 260 ℃, completely remove the condensation product.

After condensation products such as water and methanol have completely flowed out, the temperature of the reaction tube is raised to 250 to 290 ° C while the pressure is gradually reduced to 0.5 mmHg or less for about 40 to 60 minutes. while it is proceeding with the removal of the polycondensation, the pressure tube to stop stirring after about 45 minutes not decreased to below 1mmHg, and use up to nitrogen after breaking the vacuum, applying a pressure of 1.0 ~ 2.0Kg / cm ² and a melting point adhesive resin (A low melting point adhesive resin can also be produced by the same method.)

On the other hand, the catalyst usable in the preparation of the adhesive resin of the present invention is generally Mg [produced from tetraalkyl titanate alone or magnesium or calcium acetate mixture, alkali metal, alkaline earth metal or derivatives thereof or ester compounds of titanate [ Complexes of titanates such as HTi (OR) ₆ ] ₂ or inorganic titanates such as titanium titanates, mixtures of calcium acetate and antimonitoxide, lithium or magnesium acetate, organotin compounds or organotin compounds And mixtures of titanium compounds. Among these catalysts, alkali metals, alkaline earth metals or derivatives thereof, tetraalkyl titanate, antimony trioxide, and the like are particularly preferred as catalysts for producing a high melting point adhesive resin, and tetrabutyl titanate, magnesium acetate, and the like are low melting point adhesive resins. It is preferable as a catalyst at the time of manufacture.

Mixed powder state of each of the high melting point adhesive resin and the low melting point adhesive resin chip produced by the above method using a dumbler or the like at a predetermined ratio and passing through liquid nitrogen and having a powder size distribution of about 80-200 μm. As such, the adhesive resin composition of the present invention can be obtained. The adhesive resin composition of this invention obtained in this way extracts the outstanding adhesive strength, when used for the adhesion | attachment of the adhesive agent from which a surface characteristic differs.

In the copolyester-based adhesive resin composition of the present invention, when used for adhesion between adherends having different surface properties, high-melting-point adhesive resin is mainly used for mechanical bonding on surfaces such as fibers, wood, leather, and paper having rough surfaces. For glass, metal, and plastic products with smooth surfaces, low-melting-point adhesive resins with large adhesion and surface activity mainly bond to each other and exhibit excellent adhesion.

Next, specific examples of the present invention are described.

However, these examples are only for illustrating the present invention in more detail, and the present invention is not limited only to these examples.

[Examples 1-7, Comparative Examples 1-12]

According to the composition shown in the following [Table 1], first, the raw material of the high-melting-point adhesive resin was introduced into a conventional polyester reaction tube, and stirred for 2.5 hours while the tube temperature was raised from room temperature to 250 ° C. under normal pressure to obtain an oligomer. made. As the transesterification reaction proceeded, methanol began to flow out of the tube. The methanol was completely discharged by maintaining the temperature at 250 ° C. for 30 minutes. After the condensation product was removed, the pressure in the reaction tube was gradually reduced from normal pressure to 0.5 mmHg for 45 minutes, and the temperature in the tube was gradually increased to 290 ° C. to proceed with condensation polymerization while removing excess glycol component. I was. After 45 minutes from when the pressure reached 1.0 mmHg, the stirring was stopped, nitrogen was added to break the vacuum, and a pressure of 1.5 kg / cm ² was applied to prepare a high melting point adhesive resin. In addition, a low melting point adhesive resin was also prepared by treating in the same manner. The high melting adhesive resin and the low melting adhesive resin obtained in this way were mixed in the mixing ratio as shown in [Table 2], and the adhesive resin composition of this invention was obtained. This composition was sandwiched between adherends as described in Table 2 and pressed for 20 seconds at 180 ° C. for adhesion.

The adhesive bonded to it in the above manner was taken with a specimen of 2.5 cm in width and 22.9 cm in length, and subjected to an adhesive strength test at a rate of 250 mm / min in a tensile steel and an elongation tester. The results are shown in [Table 2]. Appeared.

TABLE 1

TABLE 2

* Al: Aluminum

[Examples 8-9, Comparative Examples 13-16]

Except for using a polybutylene terephthalate-based high melting point and low melting point adhesive resin polymerized according to the composition shown in [Table 3], the test piece was prepared in the same manner as in Example 1 to prepare an adhesive strength test. The results are shown in [Table 4].

TABLE 3

TABLE 4

[Examples 10-15 and Comparative Examples 17-28]

Except for using the polybutylene terephthalate-based high melting point and low melting point adhesive resin polymerized according to the composition shown in [Table 5], the specimens were prepared in the same manner as in Example 1 to test the adhesive strength. The results are shown in [Table 6].

TABLE 5

* DMS: Dimethylsulfonate Additive: Iganox

Catalyst: tetrabutyl titanate

TABLE 6

Claims (4)

Co-polyester system characterized by mixing a high melting point adhesive resin having a crystal melting point of 130-200 ℃ and a low melting point adhesive resin having a crystal melting point of 50 ~ 120 ℃ in a weight ratio of 95: 5-20: 80 Adhesive resin composition. The copolyester-based adhesive resin according to claim 1, wherein the high melting point adhesive resin is a copolyethylene terephthalate resin, and the low melting point adhesive resin is a copolybutylene terephthalate resin. Composition. The high melting point copolymerized polyethylene terephthalate-based resin according to claim 2, wherein the acid component contains terephthalic acid, isophthalic acid and lower alkyl esters thereof, and is represented by HOOC- (CH ₂ ) n -COOH. Aliphatic dicarboxylic acids having 6 to 12 carbon atoms or lower alkyl ester compounds thereof which may be used are mixed, and glycol components are prepared using ethylene glycol, 1,6-hexanediol and the like; The low melting point polybutylene terephthalate resin includes terephthalic acid, isophthalic acid and lower alkyl esters thereof as an acid component, and in addition, 6 to 6 carbon atoms which may be represented by HOOC- (CH ₂ ) n-COOH. 12 aliphatic dicarboxylic acids or lower alkyl ester compounds thereof are mixed and essentially included 1,4-butanediol as the glycol component, and ethylene glycol, 1,6-hexanediol and neopentyl glycol Copolymerized polyester-based adhesive resin composition, characterized in that it is prepared using selectively. The high-melting-point adhesive resin and the low-melting-point adhesive resin according to claim 1, wherein the acid component essentially includes terephthalic acid, isophthalic acid or lower alkyl ester compounds thereof, and HOOC- (CH ₂ ). aliphatic dicarboxylic acids having 6 to 12 carbon atoms or lower alkyl ester compounds thereof, which may be represented by n-COOH, are used in a mixed manner, and the glycol component essentially contains 50% by weight or more of 1,4-butanediol, In addition to the ethylene glycol, 1,2 or 1,3-propylene glycol, 1,6-hexanediol, neopentyl glycol is an adhesive resin composition, characterized in that the copolyester is prepared using selectively.