JP3192899B2 - Adhesive resin composition for lamination, laminate thereof and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a polyester, polyamide, polyester resin, polyamide resin, polyamide resin, polyester resin, polyamide resin, polyester resin, polyamide resin, polyester resin, polyamide resin, and the like. metal foil, in particular a laminate having a layer comprising a strong laminating adhesive resin composition provided with the adhesive and the laminating adhesive resin composition to a substrate made of polyester. Such a laminate is used as various packaging materials such as food packaging.

[0002]

2. Description of the Related Art Polyolefins have excellent heat sealing properties and moisture-proof properties and are easy to extrude. Therefore, they are used not only as materials for single-layer films, sheets or molded containers, but also for various resin films or sheets, aluminum, and the like. It is also widely used as a laminate with metal foil such as foil, paper and the like. However, polyolefins are inherently non-polar and have the disadvantage that they are difficult to adhere to different materials, especially polar materials. Therefore, various methods have been proposed for forming a multilayer laminate using a polyolefin.

[0003] For example, in order to produce a laminate of polyethylene and polyamide, not only polyethylene alone but
The following method using a modified polyolefin has been performed. (1) a modified polyolefin obtained by graft-polymerizing an unsaturated carboxylic acid or a derivative thereof to a polyolefin;
An ethylene copolymer obtained by copolymerizing ethylene and an unsaturated carboxylic acid or a derivative thereof, or a composition comprising these polymers and a polyolefin and a polyamide resin are melted and extruded from a die to form a laminate. (2) a method of preparing a polyamide film in advance and extruding and laminating (coating) a blend of polyethylene and the above-mentioned polymer, and (3) a method of preparing a polyolefin and the above-mentioned polymer. Co-extrusion lamination on a polyamide film. In addition, in order to produce a laminate of polyethylene and polyester, glycidyl methacrylate or allyl glycidyl ether is grafted onto a polyolefin, or coextruded with polyester using a polymer obtained by copolymerization with ethylene. There has been proposed a method of extrusion lamination molding on a substrate such as polyester or a polyester film.

However, in these methods, even if the adhesive strength is obtained in the case of co-extrusion, sufficient adhesive strength is imparted in the case of a laminate molding method for laminating on a substrate such as a film, a sheet or paper. Can not. In particular, it is difficult to obtain a laminate having a strong adhesive strength to a polyester-based substrate.

There is a method of increasing the temperature at the time of molding to improve the adhesive strength. However, such a polymer has poor thermal stability and causes a decomposition reaction. There is a problem that the odor remains in the body product.

Another method for improving the adhesive strength is to apply a corona discharge to the substrate. However, in this case, a special device needs to be separately prepared, and the bonding strength with the substrate is not sufficient.

[0007] In order to improve the adhesion, an ozone treatment method of oxidizing the surface by spraying ozone on a resin discharged from a die or the like is performed. The ozone treatment has an advantage that it can oxidize only the surface requiring bonding at a low temperature (Japanese Patent Laid-Open No. 57-157724). However, ozone has problems such as odor and corrosiveness, its use is still limited, and the level of adhesive strength is still insufficient. Especially, the adhesive strength is greatly increased due to moisture absorption of the laminate. There is a problem such as lowering.

[0008] As a reliable method for ensuring sufficient adhesiveness to a substrate, there is a method in which an adhesive called an anchor coat material is used in combination. In this method, an adhesive layer is interposed between the base material and the laminate resin. As the adhesive, an imine-based adhesive such as polyethyleneimine or an urethane-based adhesive is used, and in general, high adhesive strength is exhibited. Urethane-based adhesives are widely used. However, in this method, although a high adhesive strength can be obtained, the coating step is complicated, and there is a problem in safety or working environment because an organic solvent is used. Further, there is a problem that the working efficiency is greatly reduced, for example, it is necessary to prepare an anchor coating solution and wipe off the anchor coating agent attached to the roll.

[0009]

The present invention does not have the above-mentioned disadvantages and has high-speed moldability, thin-wall moldability, low neck-in property, high drawdown property, good heat-sensitive adhesive property, and good calender moldability. and polyesters, polyamides, aluminum foil, etc., of the laminate, especially having a layer comprising a strong laminating adhesive resin composition provided with the adhesive and the laminating adhesive resin composition to a substrate made of a polyester Providing is an issue.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by blending a specific compound having an epoxy group with polyethylene, and have reached the present invention. Was. That is, the present invention provides (1) (A) a melt flow rate of 0.1 to 30 g / 1.
A polyolefin having 0 minutes and (B) an epoxy compound having two or more epoxy groups in the molecule and having a molecular weight of 3000 or less, wherein the content of the component (B) with respect to the component (A) + the component (B) is laminating contact <br/> adhesive resin composition from 0.01 to 5 wt%, and a (2) a layer made of the laminating adhesive resin composition, the substrate in direct contact with the said layer, (3) A method for producing the laminate by any one of an extrusion lamination method, a heat-sensitive adhesive method, and a calendering method. Hereinafter, the present invention will be described in detail.

The polyolefin used as the component (A) in the present invention is a homo- or copolymer of ethylene or an α-olefin having 3 to 16 carbon atoms, and may be a branched low-density polyethylene (hereinafter referred to as LDPE), Examples include linear low-density polyethylene (hereinafter, referred to as LLDPE), medium / high-density polyethylene (hereinafter, referred to as HDPE), copolymers of ethylene with vinyl acetate and / or (meth) acrylate, and propylene-based polymers. Especially LDP
E is preferred. These polyolefins alone or 2
More than one species can be used.

LDPE is generally obtained by polymerization under a high pressure of 1000 to 3500 atm in the presence of a free radical generator such as peroxide, and has one of the characteristics that it has many long-chain branches. It is known to retain excellent extrudability. The reactor used for the polymerization may be either an autoclave or a tubular type.

HDPE and LLDPE can be obtained by homopolymerizing ethylene using a catalyst generally called a Ziegler catalyst, a metallocene catalyst, a Phillips catalyst, or copolymerizing ethylene with an α-olefin having 3 to 16 carbon atoms. be able to. Generally, it is produced by a medium / low pressure method, but it can also be produced by a high pressure method, and can be produced by any method such as a gas phase method, a solution method and a slurry method.

[0014] Copolymers of ethylene with vinyl acetate and / or (meth) acrylic acid ester are generally prepared by LD.
Like PE, it is obtained by polymerization in the presence of a free radical generator such as peroxide.

Examples of the propylene-based polymer include a propylene homopolymer, and a random or block copolymer of propylene and ethylene, or an α-olefin having 4 to 16 carbon atoms.

The melt flow rate of the polyolefin (J
According to IS K6758. Polyethylene resin is 190
° C, and the polypropylene resin shows the measured value at 230 ° C, hereinafter referred to as MFR).
g / 10 minutes, preferably 1 to 15 g / 10 minutes. M
When the FR is less than 0.1 g / 10 min, the high-speed moldability and the thin-wall moldability are inferior, and when it exceeds 30 g / 10 min, the heat seal strength and the neck-in property are reduced.

The epoxy compound as the component (B) in the present invention is a polyepoxy compound having a molecular weight of 3000 or less and containing at least two epoxy groups (oxirane groups) in the molecule. Epoxy compounds have at least 2
It is necessary to contain at least two epoxy groups (oxirane groups), and one epoxy group in a molecule has no effect on the adhesion to the base material intended in the present invention. The molecular weight of the epoxy compound needs to be 3000 or less, preferably 1500 or less. If the molecular weight exceeds 3,000, a sufficiently high adhesive strength cannot be obtained when the composition is formed.

As the epoxy compound, diglycidyl phthalate, diglycidyl isophthalate,
Diglycidyl terephthalate, diglycidyl adipate, trimethylolpropane polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, butanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, phenol novolac polyglycidyl ether , Epoxidized vegetable oils and the like,
Of these, epoxidized vegetable oils are preferred for imparting adhesion to a polyester substrate. Here, the epoxidized vegetable oil is obtained by epoxidizing an unsaturated double bond of a natural vegetable oil using, for example, a peracid, epoxidized soybean oil, epoxidized olive oil, epoxidized safflower oil,
Epoxidized corn oil, epoxidized linseed oil and the like can be mentioned. Epoxidized vegetable oils include, for example, O-130P (epoxidized soybean oil) and O-18 manufactured by Asahi Denka Kogyo KK
It is commercially available as OA (epoxidized linseed oil) and the like. It should be noted that the presence of an unepoxidized or insufficiently epoxidized oil which is by-produced to some extent when epoxidizing vegetable oil does not hinder the spirit and essence of the present invention.

In the present invention, the amount of the component (B) added is
The content based on the component (A) + the component (B) is 0.01 to 5% by weight, and preferably 0.01 to 0.9% by weight.
If the added amount of the component (B) is less than 0.01% by weight, the adhesive strength to the substrate is not sufficiently improved, and if it exceeds 5% by weight, the adhesive strength is improved, but the molded article emits odor. Occurs, which is not preferable.

The epoxy compound used in the present invention can be used as a stabilizer or a plasticizer for polymers such as polyvinyl chloride or a polymer compound containing a carboxylic acid group or a carboxylic acid derivative group in the molecule. There is also disclosed a technique of adding a compound as a crosslinking agent (Japanese Patent Application Laid-Open No. 60-115815). However, it is expected that these epoxy compounds will have an extremely strong adhesion-improving effect on a substrate, especially a polyester substrate, when the resin composition is simply blended with non-polar polyethylene. It was not done.
The reason for this improved adhesion is not always clear,
When the polyolefin is extruded from the extruder or from a T-die or the like during melt molding, the polyolefin is air-oxidized and reacts with an epoxy compound in the course of this oxidation. It is presumed that unreacted epoxy groups remaining in the molecule of the grafted epoxy compound react with functional groups (amino group, carboxyl group, carbonyl group, etc.) of the substrate (adherend). Epoxidized vegetable oils are particularly effective for polyesters.

The multicomponent copolymer of the olefin and the compound having a functional group which reacts with the epoxy group, which is the component (C), is not an essential component, but by adding it, the adhesiveness can be further improved.

Examples of the functional group which reacts with the epoxy group include a carboxyl group or a derivative thereof, an amino group, a phenol group, a hydroxyl group, and a thiol group. Among them, it is preferable to have at least one group selected from the group consisting of an acid anhydride group, a carboxyl group and a metal salt of a carboxylic acid in the molecule, from the balance between reactivity and stability. Copolymerization method As the method for introducing the functional group reactive with an epoxy group
Is raised.

A multicomponent of an olefin and a compound having a functional group which reacts with an epoxy group, produced by a copolymerization method.
Examples of the copolymer include a multi-component copolymer of ethylene and a compound copolymerizable with ethylene.

Compounds copolymerizable with ethylene used in the copolymerization include α, β-unsaturated carboxylic acids such as (meth) acrylic acid and α, β-unsaturated carboxylic acids such as sodium (meth) acrylate.
β-unsaturated carboxylic acid metal salts, unsaturated carboxylic anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, hydroxyethyl (meth) acrylate, (meth)
Examples include hydroxyl group-containing compounds such as allyl alcohol, and unsaturated amino compounds such as allylamine, but are not limited thereto. Further, in addition to these unsaturated compounds, a vinyl alcohol ester such as (meth) acrylate, vinyl acetate, vinyl propionate and the like may be copolymerized and used. These compounds can be used as a mixture of two or more kinds in a copolymer with ethylene. Further, two or more copolymers of these compounds and ethylene can be used in combination.

[0025]

[0026]

[0027]

[0028]

The amount of the multicomponent copolymer of the compound (C) having a functional group which reacts with the epoxy group and the olefin is generally 30 parts per component (A) + component (B) + component (C). % By weight, preferably 2 to 25% by weight, particularly preferably 5 to 20% by weight. Addition of 30% by weight or more has an effect but is not economical.

The composition of the present invention may further contain, if desired, conventional additives such as plasticizers, lubricants, various stabilizers, antiblocking agents, antistatic agents, dyes, pigments and various fillers. Is also good.

In order to obtain the adhesive resin composition for lamination of the present invention, the above components are mixed by a Henschel mixer, a ribbon mixer, or the like, or the mixture is further mixed with an open roll, a Banbury mixer, a kneader, an extruder, or the like. The method of kneading using the above may be used as appropriate. The kneading temperature is usually 110 to 350 ° C, and 120 to 300 ° C.
Is preferred.

The laminating adhesive resins set composition as the present invention for adhesion to the substrate is good, it is used as a laminate. As the base material, polyamide 6, polyamide 66, polyamide 6
66, polyamide such as polyamide 12, polyester such as polyethylene terephthalate, polybutylene terephthalate, saponified ethylene vinyl acetate copolymer (hereinafter, referred to as
A film or sheet of a thermoplastic resin such as EVOH), a resin film on which silica or aluminum is deposited, a metal foil such as iron or aluminum, paper and the like generally used as a film or sheet can be used. It may be a cloth, a nonwoven fabric, or a plate. Among these substrates, a polyamide or polyester film or sheet and an aluminum foil are preferable, and a polyester film or sheet is particularly preferable. For these substrates, corona treatment, frame treatment,
Preheating treatment, plasma treatment, or the like may be performed.

The laminate of the present invention requires that the adhesive resin layer and the substrate be in contact with each other, but may further have another layer on the adhesive resin layer or the substrate. Needless to say.

To form a laminate from the adhesive resin composition for lamination of the present invention and a base material, extrusion lamination molding, coextrusion molding, heat-sensitive bonding, calender molding, and the like can be used. Extrusion lamination molding is preferable because remarkable improvement in adhesive strength is achieved as compared with the conventional method. When the laminate of the present invention is produced by a coextrusion method, examples of the resin for coextrusion include polyamide, polyester, and EVOH.
Etc. are exemplified, but not limited thereto.

In extrusion lamination molding and coextrusion molding, it is preferable to mold at a temperature at which the polyolefin is oxidized. The molding temperature cannot be limited to a certain value in relation to the molding speed.
0 ° C. or higher, preferably 200 to 400 ° C.
-340 ° C is particularly preferred. In the case of a polypropylene resin, the temperature is generally 170 ° C. or more, and
0 ° C is preferred, and 240-320 ° C is particularly preferred. Here, since the molding speed affects the residence time in the extruder or the time in contact with air in a molten state, it is related to the oxidation of polyolefin.

In the case of extrusion laminate molding, if ozone or oxygen treatment is performed, molding can be performed at a lower temperature. Here, the ozone or oxygen treatment refers to a method of oxidizing the surface of the resin by blowing oxygen gas or ozone gas onto the resin discharged from the die. Further, the laminate manufactured by extrusion lamination molding is heated at 20 to 160 ° C.
Preferably, the heat treatment is performed at a temperature of 30 to 80 ° C., whereby the adhesive strength can be further improved, and this heat treatment can be performed as needed.

[0037]

The present invention will be described below in more detail with reference to examples and comparative examples. In addition, each physical property value of an Example and a comparative example was measured according to the following method. (1) High-speed moldability Extruder: 90 mmφ (50 rpm), T die width 750 m
m, the air gap was set to 120 mm, the take-up speed was increased at a temperature of 300 ° C., and the evaluation was made based on the speed (m / min) at which film breakage occurred. (2) Neck-in By the above device, the film thickness was 20 μm, and the take-off speed was 200 m /
And the width of the coat on the substrate was measured and evaluated by the difference (mm) from the die width. (3) Adhesive strength Extruder: 90 mmφ ( 150 rpm), T die width 750
mm, using a polyamide 6 film biaxially stretched on a substrate, a polyethylene terephthalate film,
Lamination was performed at a predetermined temperature at a molding speed of 200 m / min to obtain a laminated film. A sample obtained by subjecting this laminated film to a moisture absorption treatment (immersion in water at 30 ° C. for 24 hours) was used as a sample. The laminate sample was peeled off at the interface between the polyamide 6 or polyethylene terephthalate film and the laminate film, the sample width was 15 mm, and the peeling speed was 300.
The peel strength at 180 ° peeling at mm / min was defined as the adhesive strength. (4) Odor Extruder: 90 mmφ (50 rpm), T die width 750 m
m and a film was formed at a predetermined temperature. The following LD4 was molded at 300 ° C. and used as a comparative standard for odor. That is, 100 g of the obtained film was packed in a glass bottle, sealed, heated at 60 ° C. for 4 hours, gradually cooled to room temperature, opened, and smelled. Based on the odor of LDPE as a reference, the case where the odor level is equivalent and there is no practical problem,
A case where there was a remarkably severe practical problem was evaluated as x, and evaluated in three steps. LDPE as a comparative standard for odor is the following LD.
4 was used.

As the polyolefin as the component (A), the following polyethylene was used. LD4: MFR 4.0 g / 10 min, density 0.921 g /
LDPE of cm ³ LD19: MFR18.7g / 10 min, density 0.919
g / cm ³ LDPE LD35: MFR 35 g / 10 min, density 0.918 g /
cm ³ of LDPE

The following epoxy group-containing compound (B) was used. B-1: Epoxidized soybean oil (O-1 manufactured by Asahi Denka Kogyo KK)
30P) B-2: Epoxidized linseed oil (O-Made by Asahi Denka Kogyo KK)
180A) B-3: Diglycidyl phthalate

The copolymers used as component (C) in the examples and in the comparative examples are as follows. C-1: the content of glycidyl methacrylate is 12%,
Ethylene-glycidyl methacrylate copolymer having a number average molecular weight of 10,000 (manufactured by a high pressure method) C-2: methacrylic acid content of 8% by weight, MFR of 8
g / 10 minutes ethylene-methacrylic acid copolymer (Nucleol 0908C, manufactured by DuPont-Mitsui Polychemicals Co., Ltd.) C-3: Maleic anhydride content 2.5%, MFR 12 g /
Ethylene-maleic anhydride high pressure copolymer for 10 minutes

(Example 1) 99.5% by weight of LD4, B
After mixing each component with a Henschel mixer at a composition of -10.5% by weight, the mixture was kneaded at 180 ° C using a 40 mm co-directional twin screw extruder to produce an adhesive resin composition. Using a polyethylene terephthalate film as the obtained adhesive resin composition and a substrate, a T-die width of 750 mm was obtained by a 90 mmφ extruder ( 150 rpm).
Lamination was performed at a predetermined temperature at a molding speed of 200 m / min to obtain a laminated film. As shown in Table 1, the high-speed moldability, neck-in, adhesive strength, and odor were all good.

Examples 2 to 11 With the compositions shown in Table 1,
An adhesive resin composition was produced in the same manner as in Example 1 to obtain a laminate film. The evaluation results are shown in Table 1,
All were good in high-speed moldability, neck-in, adhesive strength, and odor.

Comparative Example 1 A laminated laminated film was obtained in the same manner as in Example 1 using only LD4, but the adhesive strength was low.

(Comparative Examples 2 to 6) Adhesive resin compositions having the compositions shown in Table 1 were produced in the same manner as in Example 1 to obtain laminated laminate films. As shown in Table 1, the evaluation results indicate that molding was not possible or high-speed moldability, neck-in, and odor were poor.

Comparative Example 7 An adhesive resin composition having the composition shown in Table 1 was produced in the same manner as in Example 1 to obtain a laminate film. As shown in Table 1, the evaluation results were poor in adhesive strength.

[0046]

[Table 1]

[0047]

EFFECTS OF THE INVENTION A laminate made of an inexpensive polyethylene-based laminating resin composition having good adhesion to a base material made of polyamide or polyester by a method such as extrusion lamination molding, heat-sensitive bonding, or calender molding. Can be industrially useful.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-67344 (JP, A) JP-A-56-136833 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 23/00-23/36 C08K 5/00-5/59 B32B 27/32

Claims (9)

(57) [Claims] (A) a melt flow rate of 0.1 to 3
A polyolefin having 0 g / 10 min and (B) an epoxy compound having two or more epoxy groups in the molecule and having a molecular weight of 3000 or less, wherein component (B) is added to component (A) + component (B). An adhesive resin composition for lamination having a content of 0.01 to 5% by weight. (A) a melt flow rate of 0.1 to 3;
0 g / 10 min polyolefin, (B) an epoxy compound having two or more epoxy groups in the molecule and having a molecular weight of 3000 or less, and (C) a compound having a functional group reactive with the epoxy group and an olefin. It is composed of a multi- component copolymer, the content of the component (B) is 0.01 to 5% by weight based on the component (A) + the component (B), and the content of the component (C) is 3%.
An adhesive resin composition for lamination that is less than 0% by weight. 3. The adhesive resin composition for lamination according to claim 1, wherein (A) the polyolefin is a branched low-density polyethylene. 4. The method according to claim 1, wherein the epoxy compound (B) is an epoxidized vegetable oil.
12. The adhesive resin composition for lamination according to the above item. 5. The multicomponent copolymer of (C) a compound having a functional group which reacts with an epoxy group and an olefin is at least one selected from the group consisting of an acid anhydride group, a carboxyl group and a metal salt of a carboxylic acid. A polyolefin resin having a group represented by the following formula in the molecule:
The adhesive resin composition for lamination according to any one of the above. 6. The product according to claim 1, wherein
A laminate comprising a layer made of a layer-forming adhesive resin composition and at least two layers of a substrate. 7. The laminate according to claim 6 , wherein the base material directly contacts the layer made of the adhesive resin composition for lamination. 8. A substrate polyester, polyamide, laminate according to claim 6 or claim 7, wherein a film or sheet made of aluminum. 9. A method for producing the laminate according to any one of claims 6 to 8 by any one of an extrusion laminating method, a heat-sensitive bonding method, and a calendering method.