JPS592453B2 - 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, ethylene-vinyl acetate copolymer (hereinafter referred to as E
VA) and/or its 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.

In particular, the object of the present invention is to obtain a resin composition that has excellent adhesion to films, sheets, and various molded products made from saturated polyester, and also has excellent melt flowability and moldability. Conventionally, an enormous number of techniques have been proposed for adhesives containing EVA or its saponified product as one component.

They can be roughly divided into the following three categories. -lEVA
Or use EVA or its saponified product as a coating agent for multilayer films, sheets, containers, paper, metals, glass, etc. EVA or its saponified product is used as an adhesive for fibers, etc. EVA or its saponified product is used in many of these materials and applications. Although some of these materials have shown sufficiently satisfactory performance, some materials still cannot be said to have satisfactory performance.

One of them is polyester adhesive.

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, and the like cannot be used for adhesion, and methods such as polyurethane dry lamination have had to be used.

However, this force method has many problems, such as insufficient adhesive strength and the use of solvents, such as air pollution and the risk of explosion, and the resulting film has a solvent odor. was. Furthermore, a method of hydrolyzing the polyester surface with an alkali to improve adhesion is also known, but this method also requires large-scale equipment for hydrolysis, and a significant increase in price is unavoidable. Ta.

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

In order to further improve the adhesive performance of EVA or its saponified product and to make it effective on more materials, the present inventors conducted extensive research and identified EVA or its saponified product and polyethyleneimine. It was discovered that a composition with improved adhesion performance to many materials can be obtained by mixing in a ratio of

Moreover, the present inventors have discovered that the composition of the present invention has extremely high adhesive performance against saturated polyester, for which conventional EVA or its saponified product has exhibited insufficient adhesive performance, and has thus arrived at the present invention. . The present invention will be explained in detail below.

EVA and/or its saponified product and polyethyleneimine are mixed and/or kneaded to form a uniform resin composition.

As the mixing and kneading method, the power method of melting and kneading with a single-screw or twin-screw extruder, and the power method of kneading with a roll, Banbury mixer, etc. are used.

The kneading temperature is determined in relation to the melting point, decomposition temperature, and decomposition temperature of polyethyleneimine of EVA or its saponified product. Specifically, the temperature is preferably 120°C or more and 200°C or less.
In addition, when polyethyleneimine is used as an aqueous solution,
In order to prevent the kneading temperature from dropping rapidly due to moisture, 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. A method using a solvent as another mixing force method can also be applied.

For example, EVA and/or its saponified product is dissolved in a good solvent such as xylene or toluene, and then dispersed in an aqueous polyenalenimine 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, EVA and/or its saponified product is dissolved in a solvent that is a good solvent for EVA 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 methods using these solvents, EVA and/or its saponified products become more easily dissolved when the method is carried out in a heated state.

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

The 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 40% by weight and a melt index (MI). 0.1~5009
/10 minutes is preferred.

Moreover, as the saponified EVA, it is preferable to saponify the above-mentioned EVA by 5 to 100%.

The saponification reaction may be carried out using an acid or an alkali as a catalyst according to a known saponification method. Polyethyleneimine, which is the object of the present invention, is a polymer of ethyleneimine obtained by polymerizing ethyleneimine with an acid catalyst.Today, it is produced with a wide range of molecular weights from several hundred to several tens of thousands. However, it is also effective for the present invention.

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 is used in its commercially available state. It can also be used after being concentrated or diluted with another medium. The quantitative proportion of EVA and/or its saponified product and polyethyleneimine is determined based on its melt viscosity, processability, mechanical strength,
It can be determined by comprehensively considering other factors.

Specifically, polyethyleneimine is preferably used in an amount of 1 to 50 parts by weight based on 100 parts by weight of EVA and/or its saponified product. This is because within this range, a resin composition with improved adhesiveness can be obtained and has physical properties that can be used in extrusion coating ink resins, films, and adhesives. As described above, the composition of the present invention is particularly effective as an adhesive between polyester and polyester or between polyester and other materials.

Furthermore, the composition of the present invention can also be used in applications where EVA or its saponified product has conventionally been used as an adhesive. In other words, surface treatment of inorganic materials such as crow, coating and adhesives of cellulose materials such as paper and fibers,
It can be applied to many uses such as metal coatings and adhesive materials for organic polymer materials, and has the effect of further increasing adhesive strength to many such materials.

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 (sheet) or a multilayer film (sheet) by coating other materials (especially polyester). Depending on the type of use, known additives such as heat stabilizers, antioxidants, anti-protective agents, slip agents, antistatic agents, colorants, etc. may be added.

An inorganic filler can also be added to the composition of the present invention within a range that does not impair its effectiveness. In this way, the composition of the present invention
It is particularly useful as an adhesive material for polyester.
Its contribution to industry, 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.

Examples 1 to 5, Comparative Examples 1 to 2 Polyethyleneimine (hereinafter referred to as PE) was prepared using a 3-inch roll.
Compositions containing different amounts of (abbreviated as I) were manufactured according to the following formulations.

After melting the saponified EVA, PEI was added and
The mixture was kneaded at C for 10 minutes.

This composition was made into a 100 μm film, which was sandwiched between a 0.1 mTfL film of polyethylene phthalate (abbreviated as PET) and a 2 mn aluminum plate, and heated at 150° C. for 0.5 μm.
1k9 was bonded under heat for 5 minutes, and its 180 degree peel strength was measured. The results are shown in Table 1. From Table 1, it can be seen that the compositions of the present invention containing a certain proportion of PEI are very effective as adhesives between polyester and aluminum.

Examples 6 to 10 Various compositions were produced in the same manner as in Examples 1 to 5, using the following various polymers instead of the saponified EVA of Example 1 and varying the PEI content.

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

Example 11, Comparative Example 3 Using the saponified EVA of Example 1, a composition containing 5 phr of PEI was prepared in the same manner as in Example 1.

Claims (1)

[Scope of Claims] 1. An adhesive resin composition prepared by blending 1 to 50 parts by weight of polyethyleneimine to 100 parts by weight of an ethylene-vinyl acetate copolymer and/or saponified product thereof containing 1 to 40% by weight of vinyl acetate. . 2 0.1 to 500 g of ethylene-vinyl acetate copolymer
A composition according to claim 1 having a melt index of /10 minutes. 3 Saponified ethylene-vinyl acetate copolymer has a melt index of 0.1 to 500 g/10 minutes and a vinyl acetate content of 1 to 40% by weight.
The composition according to claim 1 or 2, which is 100% saponified.