JPS581692B2 - adhesive resin composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to a resin composition having good adhesive strength.

More specifically, carboxylated ethylene-vinyl acetate copolymer and/or carboxylated ethylene-vinyl acetate copolymer saponified product (hereinafter referred to as carboxylated EVA and/or
The present invention relates to a resin composition comprising a carboxylated EVA saponified product) and polyethyleneimine.

The aim is to create a resin composition that has excellent adhesion to various materials such as organic polymer materials, metals, inorganic materials, and cellulose-based natural materials, as well as excellent melt flowability and moldability. It's about getting things.

Films, made from saturated polyester, among others
The object of the present invention is to obtain a resin composition that has excellent adhesion to sheets and various molded products, and also has excellent melt flowability and molding processability.

Carboxylated EVA and saponified carboxylated EVA exhibit excellent adhesion to metals, glass, resins, etc., and are widely used as hot melt adhesives, laminating resins, coating resins, etc. However, some materials For,
It could not be said that the performance was still satisfactory.

One of these is adhesion of saturated polyester.

Conventionally, polyester resin has excellent mechanical strength, water resistance, and gas barrier properties, and has been widely used as a laminate film for food packaging and retort pouches.

On the other hand, since polyester resin has poor adhesive properties, hot melt adhesives, film adhesives, etc. cannot be used for adhesion, and methods such as dry lamination of polyurethane have to be used.

However, this method has many problems, such as insufficient adhesive strength, air pollution and the risk of explosion due to the use of solvents, and the resulting film has a solvent odor. .

Furthermore, in order to improve adhesion, it is also known to hydrolyze the surface of polyester with alkali, but this method also requires large-scale equipment for hydrolysis, making it difficult to avoid a significant increase in price. There wasn't.

As described above, hot-melt adhesives and film adhesives for polyester are hardly known at present, and their appearance has been awaited.

The present inventors have further improved the adhesive performance of carboxylated EVA or saponified carboxylated EVA,
Moreover, in order to make it effective for more materials, as a result of intensive research, we found that by mixing carboxylated EVA and/or carboxylated EVA saponide with polyethyleneimine in a specific ratio, adhesive performance for many materials can be improved. They discovered that a more improved composition could be obtained and arrived at the present invention.

Moreover, the present inventors have discovered that the composition of the present invention has significantly high adhesive performance against saturated polyester, for which conventional carboxylated EVA or saponified carboxylated EVA has exhibited insufficient adhesive performance. It was reached.

Hereinafter, the present invention will be explained in detail.

Carboxylated EVA and/or carboxylated EV
A: The saponified product and polyethyleneimine are mixed and/or kneaded to form a uniform resin composition.

The mixing and blending methods include a method of melt-kneading with a single-screw or twin-screw extruder, a method of kneading with a roll, a Banbury mixer, etc.

The kneading temperature is determined in relation to the melting point, decomposition temperature, and decomposition temperature of polyethyleneimine of carboxylated EVA and/or saponified carboxylated EVA.

Specifically, the temperature is preferably 120°C or more and 200°C or less.

In addition, when polyethyleneimine is used as an aqueous solution,
It is necessary to prevent the kneading temperature from dropping rapidly due to moisture, and it is preferable to use equipment with a large heat capacity.

When kneading with an extruder or the like, steam is generated, so a device with a vent is preferable.

The kneading time may be selected so as to provide a uniformly mixed resin composition.

Furthermore, when polyethyleneimine is used as an aqueous solution, mixing involves removal of moisture, which requires kneading for a longer time.

Specifically, 5 minutes or more is suitable.

As another mixing method, a method using a solvent can also be applied.

For example, carboxylated EVA and/or saponified carboxylated EVA is dissolved in a good solvent such as xylene or toluene, and then dispersed in an aqueous polyethyleneimine solution.

At that time, it is advisable to add a dispersant.

Thereafter, the solvent and water are removed to obtain a uniform resin composition.

In addition, carboxylated EVA and/or carboxylated EVA saponified product is dissolved in a solvent that is a good solvent and has good compatibility with water, and the dissolved solvent and polyethyleneimine aqueous solution are mixed to form a uniform solution. .

There is also a method in which the solution portion is then removed to obtain a uniformly mixed resin composition.

In the methods using these solvents, it is desirable to conduct them in a heated state.

Dissolving carboxylated EVA and/or saponified carboxylated EVA in a solvent and mixing the resulting solution with polyethyleneimine (aqueous solution) are preferably carried out in an apparatus having a forced stirring mechanism.

The carboxylated EVA used in the present invention is one manufactured by either a high-pressure radical polymerization method or a solution or emulsion polymerization method, and has a vinyl acetate content of 1 to 60% by weight and a melt index of 0.1. ~
Preferably, 500 g/10 minutes of EVA is graft-polymerized with α/β-unsaturated carboxylic acid or its derivative by a known method in the presence or absence of a solvent.

In addition, as the carboxylated EVA saponified product, the above E
An α/β-unsaturated carboxylic acid or a derivative thereof was graft-polymerized by a known method in the presence or absence of a solvent to a saponified EVA obtained by saponifying 5 to 100 mol% of VA by a known method using an acid or alkali as a catalyst. Preferably, the EVA saponified product is nophesterified with the above acid or its derivative.

Specifically, α/β-unsaturated carboxylic acids and their derivatives used for carboxylation include acrylic acid, maleic acid, maleic anhydride, fumaric acid, methacrylic acid, crotonic acid, itaconic acid, α-chloroacrylic acid, etc. Can be mentioned.

The acid value of carboxylated EVA and carboxylated EVA saponide is preferably in the range of 0.1 to 20.0 mgKOH/P; below the lower limit, the effect of the present invention cannot be exhibited; If you exceed
As crosslinking progresses, the melt index drops significantly, making processing difficult.

Polyethyleneimine is usually obtained by acid-catalyzed ring-opening polymerization of ethyleneimine, and is produced with a wide range of molecular weights from several hundred to tens of thousands, but any of them is effective in the present invention and can be used for the intended purpose. You can make various selections depending on the situation.

Polyethyleneimine is also commercially available as an aqueous solution or as a starch syrup product, and when used in accordance with the present invention, it can be used as it is commercially available, or it can be concentrated or prepared in other media. It may be used diluted.

Carboxylated EVA and/or carboxylated EV
The quantitative ratio of saponified product A and polyethyleneimine is determined based on its melt viscosity, processability, and the specific use of the resin composition.
It is determined by comprehensively considering mechanical strength and other factors.

Specifically, polyethyleneimine is carboxylated E
VA and/or carboxylated EVA saponified product 100
It is preferably 1 to 50 parts by weight.

This is because within this range, a resin composition with improved adhesiveness can be obtained and has physical properties and properties that can be used in extrusion coating resins, films, and adhesives.

As described above, the composition of the present invention is particularly effective as an adhesive between polyester and other materials such as polyester or polyester.

The composition of the present invention can also be used in applications where carboxylated EVA or saponified carboxylated EVA has conventionally been used as an adhesive.

In other words, it can be applied to many applications, such as surface treatment of inorganic materials such as glass, coating and adhesives for cellulosic materials such as paper and fibers, metal coating agents, and adhesive materials for organic polymer materials. This has the effect of further increasing adhesive strength to many materials such as.

The composition of the present invention can be used effectively in any form such as film, pellet or powder.

Needless to say, it can also be used as a film or even a multilayer film (sheet) by coating other materials (especially polyester).

Depending on the form of use, known additives such as heat stabilizers, antioxidants, antiblock agents, slip agents, antistatic agents, colorants, etc. may be added.

As described above, the composition of the present invention is particularly useful as a material for adhesives for polyester, and its contribution to industries including packaging materials 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.

[Production of carboxylated EVA]

Example 1 Melt index (hereinafter abbreviated as MI) 20.0g/1
0mm, vinyl acetate content 20% by weight, Vicat softening point 57°C EVA 100 parts by weight, benzoyl peroxide 0.
05 parts by weight and 0.1 parts by weight of maleic anhydride in an inner diameter of 40 m.
Carboxylated EVA [A] was obtained by kneading at 180° C. using an extruder.

The MI of this resin was 6.7 g/10 min.

In addition, the acid value after acetone extraction of unreacted monomers using a Soxhlet extractor was 0.6 mgKOH/g.
Met.

Example 2 Carboxylated EVA [B] was obtained by changing the amount of maleic anhydride in Example 1.

MI is 4.5g/10min, acid value is 3.2mgKOH
/g.

[Production of saponified carboxylated EVA] Example 3 MI 18g/10min, vinyl acetate content 28% by weight
, Vicat EVA with a softening point of 43°C was diluted with sodium hydroxide to 80 mol% in a hexane-methanol mixed solvent.
Saponification was performed.

It was washed with methanol and vacuum dried at 60° C. for 1 day.

Using this saponified EVA, maleic anhydride was grafted under the same conditions as in Example 1 to obtain a carboxylated saponified EVA [
C] was obtained.

MI is 13.8g/10min, acid value is 0.8mgKO
It was H/g.

Example 4 By varying the amount of maleic anhydride in Example 3,
A saponified carboxylated EVA was obtained.

MI is 8.1g/10min, acid value is 3.5mgKOH
/g.

Examples 1 to 4, Comparative Examples I to ■ Carboxylation E at 130°C using a 3-inch roll
After melting VA (A) or [B], a predetermined amount of polyethyleneimine (hereinafter abbreviated as PEI) was added and kneaded for 10 minutes.

As PEI, Epomin P-10 manufactured by Nippon Shokubai Chemical Industry Co., Ltd.
00 (30% aqueous solution) was used.

This composition was made into a 100 μ film, sandwiched between a 0.1 mm polyethylene terephthalate (hereinafter abbreviated as PET) film and a 2 mm aluminum plate, and heated at 150°C.
1. Heat compression bonding was carried out under the conditions of 0.1 kg/cm for 25 minutes.
The 80 degree peel strength was measured.

The results are shown in Table-1.

Examples 5 to 8, Comparative Examples ■ to ■ Carboxylated EVA instead of carboxylated EVAO
A composition was similarly produced using a saponified product.

When the PET/Al 180 degree peel strength was measured, the results shown in Table 2 were obtained.

Claims (1)

[Scope of Claims] 1. An adhesive resin composition comprising a carboxylated ethylene-vinyl acetate copolymer and/or a saponified carboxylated ethylene-vinyl acetate copolymer and polyethyleneimine. 2. 1 part by weight of polyethyleneimine per 100 parts by weight of carboxylated ethylene-vinyl acetate copolymer and/or saponified carboxylated ethylene-vinyl acetate copolymer.
50 parts by weight of the composition according to claim 1. 3. Claim 1 or 2, wherein the carboxylated ethylene-vinyl acetate copolymer and/or the saponified carboxylated ethylene-vinyl acetate copolymer has an acid value in the range of 0.1 to 20.0 mgKOH/g. Compositions as described in Section.