JPS5951577B2 - Adhesion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of bonding polyester resins to polyester resins or other substrates.

More specifically, when bonding polyester resin to various materials such as metals such as iron and aluminum, plastics such as polyethylene, polyvinyl chloride, and polyester, and natural cellulose materials such as wood, paper, and cotton cloth, ethylene-vinyl acetate is used. The present invention relates to an adhesion method characterized in that a resin composition in which a copolymer (hereinafter abbreviated as EVA) or a saponified product thereof is blended with a phenol resin in a specific ratio is used as an adhesive. Polyester resin has excellent mechanical strength,
It has water resistance and gas barrier properties, and is widely used as a laminate film for food packaging and retort pouches.

On the other hand, because polyester resin has poor adhesive properties, hot-melt adhesives, film adhesives, etc. cannot be used for adhesion, and methods such as dry lamination using isocyanate-based anchor coatings have to be used. . However, this method is complicated to operate, has limited laminating substrates, uses a solvent, which poses problems such as air pollution and the risk of explosion, and the resulting film has a solvent odor, among other problems. It had Furthermore, a method of hydrolyzing the polyester surface with alkali to improve adhesion is also known, but this method also requires large-scale equipment for hydrolysis, and a large increase in price is unavoidable. Ta.

As described above, hot-melt adhesives and film adhesives for polyester are hardly known, and a method for bonding polyester resins to various base materials is desired.

The present inventors have conducted intensive research on an adhesive method that further improves the adhesive performance between polyester resin and various base materials, and have discovered a resin obtained by mixing EVA or its saponified product and phenol resin in a specific ratio. The present invention was achieved by discovering that polyester resin and various base materials can be strongly bonded by a method of adhering the composition as an adhesive.

The present invention is characterized in that a resin composition in which 2 to 30 parts by weight of a phenol resin is blended with 1()O part by weight of EVA or its saponified product is used as an adhesive. Provides methods for adhering base materials. E used in the method of the invention
The VA may be manufactured by any conventionally known process such as a high pressure method or a solution method.

1-500g/10mi for melt index
Preferably, the range of n<, and the vinyl acetate content is 5
It is preferable that the amount is 50% by weight. The saponified product of EVA can be obtained by partially saponifying EVA by a conventionally known method.

That is, EVA is partially saponified in a solvent such as a hydrocarbon or alcohol using an acid or alkali catalyst, or partially saponified in a molten state in a kneading device such as a roll or an extruder. obtained by The degree of saponification is preferably 1 to 80 mol%. EV
A may be manufactured by any conventionally known process such as a high pressure method or a solution method, with a melt index of 1 to 500 g/10 min and a vinyl acetate content of 5.
It is preferably 50% by weight. The phenolic resin used in the present invention is a phenol-formaldehyde resin produced by a condensation or co-condensation reaction of formaldehyde with phenols such as phenol, resorcinol, cresol, xylenol, pt-butylphenol, and P-phenylphenol. Specific gravity 0.
95 to 1.30°C, and a ring and ball softening point of 25 to 180°C. In general, there are non-thermally reactive types with extremely low methylol group content and thermally reactive types with many methylol groups, both of which have an effect on adhesive properties, but especially non-thermally reactive types. It has the effect of improving melt flowability and is also excellent in terms of processability. In order to obtain sufficient adhesive strength in bonding the polyester resin and various base materials, it is necessary that the amount of the phenol resin be 2 to 30 parts by weight per part by weight of EVAIOO. If the amount is greater than or less than this range, the adhesive strength will be insufficient for bonding the polyester resin and various base materials. EV
A or its saponified product and the phenolic resin are mixed and/or kneaded to form a uniform resin composition. The mixing and kneading methods include melt-kneading using a single-screw or twin-screw extruder, kneading using rolls, a Banbury mixer, and the like. The kneading temperature may be within a range where the resin melts and does not cause decomposition, but the kneading is usually carried out at 120°C or higher and 250°C or lower. As the kneading time, the time required to obtain a uniformly mixed resin composition may be selected. As another mixing method, a method using a solvent can also be applied.

For example, it is also possible to use toluene, xylene, dithalolethane, etc., which are good solvents for EVA, its saponified product, and phenol resin, and mix them in a solution state. In the bonding method of the present invention, the base material to be bonded to the polyester resin includes polymeric materials such as polyethylene, polyvinyl chloride, polystyrene, polyester, and polyamide, metals such as iron and aluminum, wood, cellulose such as cotton, and hemp. A wide range of materials can be used, including natural materials.

In carrying out the present invention, a resin composition consisting of EVA or its saponified product and a phenolic resin is used in the form of a film. Needless to say, it can also be used as a film by coating polyester or other materials. The bonding of the present invention is carried out by thermocompression bonding, and the bonding temperature, pressure, and time are appropriately selected, but
Bonding is possible with pressure and short time.

Additionally, known additives, such as heat stabilizers, antioxidants, anti-blocking agents, slip agents, antistatic agents, colorants, etc., may be added to the resin composition consisting of EVA or its saponified product and phenolic resin, as necessary. May be added.

Inorganic fillers can also be added to the composition of the present invention within a range that does not impair its effectiveness. As described above, the adhesion method of the present invention is useful as a method for bonding polyester and various materials, and the products obtained by implementing the present invention are extremely useful in the field of packaging materials, etc., and contribute to the industry. is extremely large.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited in any way.

Examples 1 to 3 Comparative Examples Using a 1 to 33 inch roll, the amount of phenolic resin was varied for 10 minutes at 170°C, 28% by weight of vinyl acetate, 18 g of melt index.
/ 10 min (7) Kneaded with EVA.

As the phenolic resin, CKM- manufactured by Showa Union Gosei Co., Ltd.
2400 (ring and ball softening point 145℃, specific gravity 1.08g/C
c) was used. This resin composition was made into a 100 μm film, which was sandwiched between a 0.1 mm polyethylene terephthalate (PET) film and a 2 mm aluminum plate at 150° C.
1kg/Cm2 for 5 minutes, then 180
The peel strength was measured.

The results are shown in Table 1. From Table 1, it can be seen that the bonding method of the present invention using EVA mixed with a specific proportion of phenol resin as an adhesive is extremely effective for bonding PET and aluminum.

Examples 4 to 8 In the same manner as in Examples 1 to 3, using a resin composition consisting of 100 parts by weight of the following EVA and its saponified product and 10 parts by weight of phenol resin (CKM-2400 manufactured by Showa Union Gosei), The peel strength was measured.

The results are shown in Table 2. A: Vinyl acetate content 10%, melt index 3g/10min (7) EVAB: Vinyl acetate content 20%, melt index 20g/1
0min (7) EVAC: Vinyl acetate content 32%, melt index 30g/10min (7) EVAD:
Vinyl acetate content 28%, melt index 18g/
10min (7) 40% saponified EVA E: vinyl acetate content 32%, melt index 30g/10mi
n(7) 20% Saponified EVA Table 2 Which EVA. In the case of saponified EVA and no phenolic resin, the PET/All 8O degree peel strength was 0.5 kg/25 mm or less.

Example 9 In the same manner as in Examples 1 to 3, an EV with a vinyl acetate content of 20% by weight and a melt index of 20 g/10 min was prepared.
Weight parts of AIOO and phenol resin (CKM-2103 manufactured by Showa Union Gosei [ring and ball softening point 110'C, specific gravity 1.
PET and Al were bonded using a resin composition containing 10 parts by weight of 07g/Cc)).

Its 180 degree peel strength is 2.1 kg/25 mm,
0.5kg/25mm if phenolic resin is not used
It was below. Examples 10-13 Melt index 20g/10minEVA100 with vinyl acetate content 20% by weight in the same manner as in Examples 1-3
Weight parts and phenolic resin (CKM- manufactured by Showa Union Gosei Co., Ltd.)
2400) PE using a resin composition consisting of 10 parts by weight
The T and various base materials were attached.

Table 3 shows the results of 180 degree peel strength. Table 3

Claims (1)

[Claims] 1. In a method of bonding polyester resin and polyester resin or other base materials, 20 to 30 parts by weight of phenolic resin is blended with 100 parts by weight of ethylene-vinyl acetate copolymer or saponified product thereof. An adhesion method characterized in that a resin composition comprising: 2 1 to 500 g as ethylene-vinyl acetate copolymer
2. A process according to claim 1, using said copolymer having a melt index of /10 min and containing from 5 to 50% by weight of vinyl acetate. 3 As a saponified product of ethylene-vinyl acetate copolymer,
1 to 80 mol% of vinyl acetate groups in an ethylene-vinyl acetate copolymer having a melt index of 1 to 500 g/10 min and containing 5 to 50% by weight of vinyl acetate
The method according to claim 1, which uses a saponified product of the copolymer.