JPH0618955B2 - Adhesive resin composition for heat sealing - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive composition for heat sealing. More specifically, it relates to a composition useful as an adhesive resin layer of an aluminum sheet for heat sealing a mouth of a glass container such as food.

Conventional technology In the food industry in recent years, instead of the conventional technology of filling a glass container with food and then sealing the mouth with a screw cap, the mouth is heat-sealed using a special aluminum sheet. The so-called capless seal packaging technology is drawing attention. This aluminum sheet is usually 2
It has a laminated structure in which various adhesives are coated or laminated directly on one surface of an aluminum foil having a thickness of about 0 μ to 70 μ or via a plastic layer such as a polyethylene film.

Such an adhesive is required to have a strong adhesiveness to a film such as aluminum or polyethylene as a base material and an appropriate adhesive force to a glass. That is, it is first necessary to have a sufficient adhesive force for completely sealing the glass container and a so-called easy peel property that can be easily peeled off when the glass container is opened. In addition, even if the sealed portion of the glass container is slightly contaminated by the contents such as food, it must exhibit sufficient adhesive strength.

On the other hand, it is required that the adhesive has a so-called clean peel property so that a part of the adhesive does not remain in the bottle mouth and stain the bottle mouth when opened. Furthermore, the product in which the glass container is filled with food may be stored for a long period of time, and the adhesive performance should not be deteriorated during this period. In particular, if the content of the glass container is a liquid such as juice or liquor, or if it is a food containing a high percentage of water such as jam or marmalade, it will adhere even if it is always in contact with water. It is an essential requirement that performance does not deteriorate over a long period of time.

Further, in view of workability up to sealing, it is required that the adhesive layer of the aluminum sheet does not show blocking property. Generally, in the food industry, a filling operation of food into a glass container and a sealing operation with an aluminum sheet are performed in a series of steps. The aluminum sheet is first punched into a specified shape and then molded, and then set one by one at the correct position above the container mouth via a collector, shooter, etc. If the aluminum sheet has blocking properties, punching molding The mold releasability at the time is deteriorated, and smooth transfer of the sheet to the container opening is hindered, which significantly reduces the food filling work efficiency.

Heretofore, it has been attempted to use various well-known hot melt adhesives as heat seal adhesives. The present inventors applied ethylene-acrylic acid copolymer to a modified resin obtained by introducing a carboxyl group into a saponified product obtained by saponifying an ethylene-vinyl acetate copolymer (hereinafter, sometimes abbreviated as HEVA-C). The resin composition obtained by melt-mixing (melt-blending) of a coalesced product, an ethylene-methacrylic acid copolymer or an ionomer thereof has various excellent properties required for an adhesive for a heat-sealing aluminum sheet. It has been found to be particularly useful as an adhesive for heat sealing.

Conventionally, as a heat-sealing adhesive, for example, a metal salt of a monoolefin-unsaturated carboxylic acid copolymer or a product obtained by blending the metal salt with a monoolefin-unsaturated carboxylic acid copolymer is known. However, they still have a problem in terms of water resistance, and therefore, it is difficult to use them for sealing a container filled with a food containing water. In addition, such a copolymer resin film originally has a blocking property, and therefore it was indispensable to use various additives.

Further, a modified resin in which a carboxyl group is introduced into a saponified product obtained by saponifying an ethylene-vinyl acetate copolymer has been proposed. However, an aluminum sheet produced by using this resin alone has blocking properties, and has a drawback that the working speed cannot be increased when actually performing the filling and sealing work using this. On the other hand, although the water resistance is improved by using this resin, when the sheet is heat-sealed in the bottle mouth, the temperature is usually 200 ° C. or higher, and in fact 250 to 270 ° C. Does not show adhesive strength. Heat-sealing at such a high temperature may deteriorate the food adhered near the bottle mouth at the time of heat-sealing, and at the time of sealing, for example, in the heat source part of the heat sealer for preventing damage to the bottle mouth, for example, It is customary to use a cushioning material such as heat-resistant rubber in combination, but problems such as deterioration and decomposition of this occur. Therefore, in the food industry, heat sealing can be performed at a low temperature of 200 ° C. or lower, preferably 150 to 180 ° C., and even when heat sealing is performed under such mild conditions, excellent adhesive strength and water resistance are exhibited. Although there is a strong demand for the development of a heat-adhesive resin composition, such a composition has not been proposed yet.

Means for Solving the Problems An object of the present invention is to provide a heat-adhesive resin composition having a low-temperature heat-sealing property and having excellent easy peel property, clean peel property and water resistance. Another object of the present invention is to provide a heat-adhesive resin composition having extremely little blocking property when formed into an aluminum sheet.

That is, the present invention provides (a) a vinyl acetate content of 10-55.
A modified resin having a carboxyl group obtained by reacting an unsaturated carboxylic acid or a dicarboxylic acid anhydride with a partially saponified ethylene-vinyl acetate copolymer in an amount of wt%;
(b) A monoolefin- (meth) acrylic acid copolymer resin having an (meth) acrylic acid content of 1 to 30% by weight or an ionomer thereof is used in a ratio of (a) to (b) of 30/70 to 97/3.
Is an adhesive resin composition for heat sealing, which is contained in a weight ratio of.

First, the resin component (a) of the heat-sealing adhesive resin composition used in the present invention will be described.

The ethylene-vinyl acetate copolymer (hereinafter, abbreviated as EVA) used as a raw material for producing this resin component has a vinyl acetate content of 10 to 55% by weight, and more preferably 25 to 45% by weight. Use one. EVA having such a content is produced by a known production method such as a high pressure method, and its melt index (g / 10 min: AS
According to TM1238-65T. The same applies hereinafter) is 0.1-5
00, preferably 1 to 300 can be used. The EVA raw material is then subjected to a saponification reaction to obtain a partially saponified product of EVA (abbreviated as HEVA). The saponification degree is usually 10% to 98%, preferably 2
It is 0 to 80%, more preferably 30 to 70%. The saponification reaction may be carried out by a conventionally known method, for example, a system comprising a low boiling point alcohol such as methanol and ethanol and an alkali such as sodium hydroxide, potassium hydroxide and sodium methylate.
Then, using such HEVA, the modified resin (a) having a carboxyl group can be produced. Methods for introducing a carboxyl group into HEVA include a method utilizing a graft reaction and a method utilizing an esterification reaction. To utilize the grafting reaction, an unsaturated carboxylic acid is reacted. Examples of such unsaturated carboxylic acids include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and itaconic acid, or unsaturated dicarboxylic acids such as maleic acid (or their anhydrides). ) Can be mentioned, but acrylic acid is usually used. The graft reaction may be carried out under normal reaction conditions using a radical initiator such as benzoyl peroxide, lauroyl peroxide, α, α′-azobisisobutyronitrile. The unsaturated carboxylic acid is 0.1 to 15% by weight, preferably 0.5 to 5% by weight based on HEVA.
Used at a weight percentage. The modified resin having a carboxyl group obtained by such a reaction generally has an acid value of 0.5 to 120, preferably 3 to 50. Also,
When the esterification reaction is used, the dicarboxylic acid anhydride is reacted under the esterification conditions usually used. Examples of such dicarboxylic acid anhydrides include maleic anhydride, succinic anhydride, phthalic anhydride, and hexahydrophthalic anhydride. The amount of the dicarboxylic acid anhydride used is the amount necessary to esterify 5 to 60 mol%, preferably 10 to 50 mol% of the hydroxyl groups in HEVA. The modified resin having a carboxyl group obtained by this esterification reaction generally has an acid value of 10 to 200, preferably 20 to 150.

Next, the resin component (b) of the heat-sealing adhesive resin composition used in the present invention will be described.

The monoolefin- (meth) acrylic acid copolymer resin [hereinafter, sometimes abbreviated as the resin component (b-1)] is a monoolefin-acrylic acid copolymer resin or a monoolefin-methacrylic acid copolymer resin. , Basically, for example ethylene, propylene, butene-1, isobutene,
4-methylpentene-1, hexane-1, heptene-1
It is a resin obtained by copolymerizing an α-monoolefin with acrylic acid or methacrylic acid, and usually an ethylene-acrylic acid copolymer resin or an ethylene-methacrylic acid copolymer resin is used. The molecular weight of such a copolymer resin component is 1000 to 200,000, and the content of (meth) acrylic acid in the copolymer is 1 to
It is 30% by weight, preferably 2 to 20% by weight. Such resin components and their manufacturing methods are known. In the present invention, commercially available products (for example, EAA435, EAA452, EA
A455, EAA459, EAA XO-2375.3
Ethylene-acrylic acid copolymer resins such as 3; sold by Dow Chemical Japan Co., Ltd. can be used as they are.

In addition, monoolefin- (meth) acrylic acid copolymer resin
As the ionomer of fat, the above-mentioned copolymer resin, particularly
Based on ethylene-methacrylic acid copolymer resin,
The carboxyl group of this resin is used, for example,
Alkali metal ions such as aluminum or zinc,
Medium in group II metal ions such as magnesium
Ion-crosslinked resin obtained by
The fat component (b-2) may be abbreviated).
it can. In the present invention, Zn⁺⁺Type ionomer resin
Preference is given to using. Such a resin component (b-
2) Known per se and its manufacturing method (eg British patent)
No. 1,011,981). In the present invention
Is a commercially available product (for example, HI-MILAN  1554,1
555, 1557, 1601, 1605, 1650, 1
652, 1702, 1706, 1707, 1855, 1
Ionomer resins such as 856; DuPont Mitsui Polychemi
Cal Co., Ltd. can be used as it is. this
The acid content of things (methacrylic acid, acrylic acid) is 5-18
%, The degree of ionization is several% to 90%. In the present invention,
The resin component (b-1) and its ionomer (b-2)
You may use the mixture of.

The adhesive resin composition for heat-sealing of the present invention comprises the above resin component
It can be produced by melt-mixing (a) and (b). The blending ratio of both components is 70 to 3% by weight of the resin component (b) with respect to 30 to 97% by weight of the resin component (a) (total 100
% By weight; the same applies hereinafter). When considering the low temperature heat-sealing property and water resistance, which are the characteristics of the composition of the present invention, or easy peeling property, and further blocking property,
Component (a) 30 to 90% by weight, component (b) 70 to 10% by weight, component (a) 50 to 90% by weight and component (b) 5
0 to 10% by weight is preferred. When the resin component (a) exceeds the above range, blocking properties will be strongly exhibited in the sheet adhesive layer, and when it is less than the above range, water resistance,
The physical properties such as clean peel property will be inferior.

The melt mixing of both components (a) and (b) is usually carried out using a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader or the like under a temperature condition of approximately 120 to 180 ° C. The heat-sealing adhesive resin composition thus uniformly melt-mixed generally has a melt index of about 1 to 150 and is excellent in melt fluidity. This can be processed into various shapes such as powder, pellets, fibers, sheets, and films, depending on the purpose of use.
In particular, since it has good melt fluidity, it can be easily formed into a film by, for example, an inflation molding method or a cast molding method.

Incidentally, the composition of the present invention, as long as it does not impair the effects such as low-temperature heat sealability and water resistance, appropriately antioxidant, light stabilizer, heat stabilizer, colorant, lubricant, plasticizer, processability Various commonly used additives such as improving agents may be added. The mixing ratio of these additives and fillers is not particularly limited, but is usually preferably about 10% by weight or less based on the resin composition.

The heat-sealing adhesive resin composition of the present invention comprises various substrates, for example, inorganic materials such as glass and quartz, metal materials such as iron and aluminum, synthetic resin materials such as polyethylene, polypropylene, and polyethylene terephthalate. It can be used as an adhesive. To bond a substrate using the composition of the present invention, 150-250
A method of heat bonding at a temperature of 60 ° C., preferably 160 to 220 ° C. is adopted. Generally, the adhesion pressure is from contact pressure to about 10 kg / cm ² , and the adhesion time is from 1 second to 30 minutes, and these conditions may be appropriately set according to the purpose.

INDUSTRIAL APPLICABILITY The heat-sealing adhesive composition of the present invention is useful as an adhesive layer of an aluminum foil heat-sealing sheet used, for example, in the food industry when hermetically sealing the mouth of a glass container.

Among the adhesive resin compositions for heat-sealing of the present invention, the aluminum sheet for heat-sealing prepared by using the composition obtained by melt-mixing the resin component (a) and the resin component (b-2) is a blocking sheet. It has extremely low properties and, therefore, has the feature that no addition of an antiblocking agent is required at all. Further, this aluminum sheet also has a high-temperature sealing property, and has an advantage that it can be used as an aluminum sheet for high-temperature packs.

Hereinafter, the case where the adhesive resin composition for heat sealing of the present invention is used for such a heat sealing sheet will be described.

Generally, as a heat-sealed aluminum sheet such as a glass container,
20 ~ 7 directly on one side of aluminum foil with a thickness of 20 ~ 70μ
Prevents corrosion of the sheet or aluminum foil provided with a heat-adhesive resin layer having a thickness of about 0 μm due to the contents,
A laminated sheet in which a thermoplastic resin film layer such as polyethylene, polypropylene or polyethylene terephthalate having a thickness of about 15 to 30 μm is previously provided between the aluminum foil and the adhesive resin layer to serve as a cushioning material at the time of heat sealing is there. The composition of the present invention can be used as the heat-adhesive resin layer of such a sheet. For example, in the case of a sheet consisting of aluminum foil and adhesive layer,
It can be produced by extrusion laminating the heat-sealing adhesive composition of the present invention onto an aluminum foil, or dry laminating the film-shaped composition of the present invention using an isocyanate-based adhesive. Also,
In the case of a laminated sheet via a film layer, first, an isocyanate-based anchor coating agent is applied on an aluminum foil, a polyethylene layer is formed thereon by, for example, extrusion lamination, and subsequently, a polyethylene layer of the present invention is formed on the polyethylene layer. It can be produced by extrusion lamination of the heat-sealing adhesive resin composition. Further, a polyethylene film is adhered to an aluminum foil using an isocyanate-based adhesive, and subsequently, a film-like adhesive resin composition for heat sealing of the present invention is dry-laminated using a similar adhesive on the polyethylene film. Can also be manufactured by.

In order to seal the mouth of the glass container using the heat-sealing sheet produced in this way, a conventional heating means such as an induction sealing method using high frequency or a method using a heating plate can be used. The heating temperature is 150 to 250 ° C., and normally, heat sealing may be performed under a pressure of 0.1 to 10 kg / cm ² for 1 to 5 seconds, and the preferable heat sealing condition is 160 to 220 although it depends on the composition. ℃, 2
~6kg / cm ^2, 1 to 2 seconds.

Effects of the Invention The glass container heat-sealed in this manner does not show any decrease in adhesive strength even after long-term storage even if the content is a liquid containing water, and is extremely sealed. It is excellent. Moreover, it has an easy peeling property when peeling off the seal portion at the time of use, and has an advantage that the adhesive does not remain in the bottle mouth as it is and does not stain the bottle mouth (clean peeling property). Further, the aluminum sheet prepared by using the resin composition of the present invention has a low blocking property, and therefore, the workability of filling and sealing foods can be greatly improved. Furthermore, the aluminum sheet prepared by using the resin composition of the present invention has good heat sealability even when the periphery of the mouth of the glass container is contaminated with food, and the sealing is incomplete. The occurrence rate of various products is extremely low.

Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 Ethylene-vinyl acetate copolymer (Evaflex 15
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 33 weight
%, Melt index 30)
1.0% by weight of acrylic acid to
HEVA-C (melt index manufactured by grafting
Box 15) and ethylene-acrylic acid copolymer (EAA
XO-2375.33; manufactured by Dow Chemical Japan Co., Ltd .:
Acrylic acid 20% by weight, melt index 300)
Are blended in the proportions shown in Table I, and each is uniaxially 30 mmφ
9 kinds of heat seal by melt mixing at 130 ℃ using an extruder
An adhesive resin composition was prepared.

The following experiment was conducted for each composition.

That is, the composition was placed on an aluminum foil having a thickness of 50 μm and press-formed at 150 ° C. using a pressure press machine to obtain 10
An adhesive resin layer having a thickness of 0 μ was provided on the aluminum foil. The aluminum foil sheet having the obtained resin layer was placed on a flat float glass plate (30 × 100 × 3 mm) so that the resin layer of the foil was in contact with the glass plate, and this was placed at 160 ° C. using a heat sealer. An adhesive test piece was prepared by heat-sealing for 1 second under the condition of ² kg / cm ² .

180 ° peeling adhesive strength test (JIS
K-6854). Further, the same test piece was immersed in water for 6 months, and the change with time of the adhesive force was examined. The results are shown in the table below.

Example 2 Ethylene-vinyl acetate copolymer (Evaflex 15
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 33 weight
%, Melt index 30)
Acrylic acid (3.0% by weight) to the compound (saponification rate 50%)
HEVA-C (melt index manufactured by grafting
Cus 8.5) 70 parts by weight of ethylene-acrylic acid copolymer
(EAA XO-2375.33; Dow Chemical Japan
Co., Ltd .; acrylic acid 20% by weight, melt index
300) 30 parts by weight using a 30 mmφ uniaxial extruder
Melt and mix at 130 ℃, heat of melt index 27
An adhesive resin composition for sealing was obtained.

Using this resin composition, a resin sheet having a thickness of 50 μm is formed on the polyethylene film side of a laminated sheet of aluminum foil (50 μm thick) and polyethylene film (15 μm thick) which is bonded using an isocyanate adhesive. Extrusion lamination was performed to prepare a heat-sealed sheet.

This sheet is a glass container (contents 300cc, caliber 77mm
φ, untreated, filled with water), and heat-pressed for 1 second under the condition of 160 ° C. × 2.0 kg / cm ² using a heat sealer to seal the bottle mouth.

This product has a sealing strength (180 ° peel adhesion strength) of 260
The value was 0 g / 15 mm (average value at 4 points). When the pressure resistance was measured using the same sealed bottle, it was 1.1 kg.
/ cm ² was shown. When the sealed portion was peeled off, it was easily peeled off, and no resin component was adhering to the glass surface at the mouth end of the container.

Create a sealed container after filling it with water as above,
The container was left upside down for 6 months at room temperature. The sealing strength of this product is 2500g / 15mm
Met.

Example 3 Ethylene-vinyl acetate copolymer (Evaflex Four
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 40 weight
%, Melt index 55)
2.5% by weight of acrylic acid to the halide (saponification rate 40%)
HEVA-C produced by graft reaction (melt-in
Dex 10) 80 parts by weight and ethylene-acrylic acid copolymer weight
Combined (EAA 459; Dow Chemical Japan Co., Ltd.);
Acrylic acid 8% by weight, melt index 9) 20% by weight
Melting and mixing the parts with 140 ° C, a uniform adhesive tree for heat sealing
A fat composition was produced.

This composition was press-molded at 150 ° C. to prepare a 100 μ thick adhesive sheet. This sheet is sandwiched between two aluminum plates (200 × 200 × 0.2 mm), and this is pressed under a condition of 150 ° C. × 100 kg / cm ² using a pressure press machine.
It was thermocompression bonded for 0 minutes to obtain an adhesive test piece. 18 of this thing
A 0 ° peel adhesion test showed a value of 14 kg / 25 mm. The same test piece was dipped in water for 6 months, and the adhesive strength of this test piece was measured to show a value of 12.8 kg / 25 mm.

Example 4 Ethylene-vinyl acetate copolymer (Evaflex 20
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 28 weight
%, Melt index 150) was obtained by saponification
Anhydrous hexahydrophthalate on saponified product (saponification rate 90%)
HEVA-C produced by esterification reaction of acid (S
Tellurization rate 25%, melt index 65) 60 parts by weight
And ethylene-acrylic acid copolymer (EAA 435;
U Chemical Japan Co., Ltd .; acrylic acid 3.5% by weight,
Melt index 11.0) 40 parts by weight and 130 ° C
Melt mixing to produce a uniform adhesive resin composition for heat sealing
did.

Using this composition, a heat-sealed sheet material was prepared in the same manner as in Example 2.

Using this sheet material, the bottle mouth of the glass container was sealed in the same manner as in Example 2. The 180 ° peel adhesion strength of this product was 2000 g / 15 mm. After peeling, no resin component was adhering to the glass surface of the container mouth.

Example 5 Ethylene-vinyl acetate copolymer (Evaflex 15
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 33 weight
%, Melt index 30)
1.0% by weight of acrylic acid to
HEVA-C (melt index manufactured by grafting
Cus 15) 75 parts by weight and zinc ion type ionomer
-Resin (zinc salt of ethylene-methacrylic acid copolymer;
Imiran 1702; Mitsui DuPont Polychemical
30 mmφ with 25 parts of Melt Index 14)
For heat sealing by melt mixing at 130 ° C using a single screw extruder
An adhesive resin composition was prepared.

This composition was placed on an aluminum foil having a thickness of 50 μm, and this was press-molded at 150 ° C. using a pressure press machine to provide an adhesive resin layer having a thickness of 100 μm on the aluminum foil. An aluminum foil having the obtained resin layer was applied to a flat float glass plate (30 × 10
0 × 3 mm) so that the resin layer of the foil is in contact with the glass plate, and this is placed at 180 ° C. using a heat sealer.
An adhesion test piece was prepared by heat sealing for 2 seconds under the condition of 1.1 kg / cm ² . The adhesive layer surfaces of the test pieces did not show blocking properties.

180 ° peeling adhesive strength test (JIS
K-6854) 2000g / 10mm
Showed the adhesive strength of. After the peeling test, the glass surface was clean and no resin layer was attached. Further, the same test piece was immersed in water for 6 months, and the change with time of the adhesive force was examined. As a result, the adhesive force was 1950 g / 10 mm.

Example 6 Ethylene-vinyl acetate copolymer (Evaflex 15
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 33 weight
%, Melt index 30)
Acrylic acid (3.0% by weight) to the compound (saponification rate 50%)
HEVA-C (melt index manufactured by grafting
Cus 8.5) 75 parts by weight and zinc ion type iono
Mer resin (zinc salt of ethylene-methacrylic acid copolymer;
High milan 1702; Mitsui DuPont Polychemical
Manufactured by KK, melt index 14) 25 parts and 30 mm
Melt and mix at 130 ° C using a φ single screw extruder,
To obtain an adhesive resin composition for heat-sealing of index 27
It was

Using this resin composition, a resin sheet having a thickness of 50 μm is formed on the polyethylene film side of a laminated sheet of aluminum foil (50 μm thick) and polyethylene film (15 μm thick) which is bonded using an isocyanate adhesive. Extrusion lamination was performed to prepare a heat-sealed sheet.

This sheet was punched into a specific shape corresponding to the mouth of the glass container using a punching press. When pressing
The adhesive layer of the sheet had no blocking property and could be smoothly molded.

Also, this sheet material is set in the bottle mouth of a glass container (contents 300cc, caliber 70mmφ, untreated, filled with water) and heat-pressed for 2 seconds under the condition of 180 ° C × 160kg / piece using a heat sealer. Then, the bottle mouth was sealed.

This product has a sealing strength (180 ° peel adhesion strength) of 250.
The value was 0 g / 15 mm (average value at 4 points). The pressure resistance measured using the same sealed bottle was 0.9 kg.
/ cm ² was shown. When the sealed portion was peeled off, it was easily peeled off, and no resin component was adhering to the glass surface at the mouth end of the container.

Create a sealed container after filling it with water as above,
The container was left upside down for 6 months at room temperature. The adhesive strength of the sealed part of this product is 2400g / 15mm
Met.

Example 7 Ethylene-vinyl acetate copolymer (Evaflex Four
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 40 weight
%, Melt index 55)
2.5% by weight of acrylic acid to the halide (saponification rate 40%)
HEVA-C (melt index manufactured by grafting
Cus 10) 80 parts by weight and zinc ion type ionomer
-Resin (zinc salt of ethylene-methacrylic acid copolymer;
Imiran 1652 Mitsui DuPont Polychemical Co., Ltd.
Manufactured, melt index 5) 20 parts by weight at 150 ° C
It is melt-mixed to produce a uniform adhesive resin composition for heat sealing.
It was

This composition was press-molded at 150 ° C. to prepare a 100 μ thick adhesive sheet. This sheet is sandwiched between two aluminum plates (200 × 200 × 0.2 mm), and this is pressed under a condition of 150 ° C. × 100 kg / cm ² using a pressure press machine.
It was thermocompression bonded for 0 minutes to obtain an adhesive test piece. 18 of this thing
A 0 ° peel adhesion test showed a value of 12 kg / 25 mm. The same test piece was dipped in water for 6 months, and the adhesive strength of this test piece was measured to find a value of 11.5 kg / 25 mm.

Example 8 Ethylene-vinyl acetate copolymer (Evaflex 22
0: Mitsui Polychemical Co., Ltd .: Vinyl acetate 28 weight
%, Melt index 150) was obtained by saponification
Anhydrous hexahydrophthalate on saponified product (saponification rate 90%)
HEVA-C produced by esterification reaction of acid (S
Tellurization rate 25%, melt index 65) 80 parts by weight
And sodium ion type ionomer resin (Ethile
Sodium salt of methacrylic acid copolymer; Himilan
1707 Mitsui DuPont Polychemical Co., Ltd., Mel
Melted at 140 ° C with 20 parts by weight of 0.9)
The mixture was mixed to produce a uniform adhesive resin composition for heat sealing.

Using this composition, a heat-sealed sheet was prepared in the same manner as in Example 6. No blocking property was observed in the resin layer of this sheet.

Using this sheet, the bottle mouth of the glass container was sealed in the same manner as in Example 6. This product has a 180 ° peel strength of 2
It was 050 g / 15 mm. After peeling, no resin component was adhering to the glass surface of the container mouth.

Example 9 The modified resin having a carboxyl group used in Example 1 (H
EVA-C) 70 parts by weight, ethylene used in Example 1
Acrylic acid copolymer (EAA XO-2375.33)
15 parts by weight and Zn used in Example 5⁺⁺Ionic type
Ionomer resin (High Milan 1702) 15 parts by weight
Adhesive resin for heat sealing, which is obtained by melting and mixing and at 140 ° C
A composition was produced.

Using this composition, a heat-sealed sheet was prepared in the same manner as in Example 6.

Using this sheet, the mouth of the glass container was sealed in the same manner as in Example 6. This product has a 180 ° peel strength of 2
It was 000 g / 15 mm. After opening, no adhesion of the adhesive to the container opening was observed.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area C08L 29/04

Claims (1)

[Claims] 1. A vinyl acetate content of (a) 10-55% by weight
A modified resin having a carboxyl group obtained by reacting a partially saponified ethylene-vinyl acetate copolymer with an unsaturated carboxylic acid or a dicarboxylic acid anhydride, and (b)
Containing a monoolefin- (meth) acrylic acid copolymer having a (meth) acrylic acid content of 1 to 30% by weight or an ionomer thereof in a weight ratio of (a) to (b) of 30/70 to 97/3. An adhesive resin composition for heat-sealing.