JP2003103734A - Laminated film and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film which shows superb hygienic quantities, high water resistance, high alkalinity resistance, coating film adhesive and excellent heat sealing characteristics. SOLUTION: This laminated film has a layer composed of a polyolefin resin with a thickness of 0.01 to 10 μm formed on at least one of the sides of a thermoplastic resin film and is characterized in that an emulsifier or a chemical compound having a protecting colloidal action is not substantially included in a polyolefin resin layer. The polyolefin resin is a copolymer composed of an unsaturated carboxylic acid or its anhydride (A1), an ethylene hydrocarbon (A2) and at least one kind of chemical compounds (A3) selected from I-IV chemical compounds. In addition, the mass ratio of the constituent components (A1) to (A3) satisfies the formulae (1): 0.01<=(A1)/ (A1)+(A2)+(A3)}×100<5 (1) and (2): (A2)/(A3)=55/45 to 99/1 (2).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a laminated film in which a polyolefin resin having a specific composition is thinly laminated on a thermoplastic resin film. More specifically, it relates to a laminate film having hygiene, water resistance, alkali resistance, adhesiveness and heat sealability.

[0002]

2. Description of the Related Art Polyolefin resins such as ethylene-unsaturated carboxylic acid copolymers can form coatings having good thermal adhesiveness, and are therefore used as fiber treatment agents, coating agents, heat seal agents, part coat agents, etc. Widely used in.

When laminating such a polyolefin resin on a film, there are a method of melting and laminating a solid resin and a method of coating a film with a liquid prepared by dissolving or dispersing the resin in a solvent or an aqueous medium. It is difficult to laminate the polyolefin resin thinly and uniformly by the method of. Among the latter, the aqueous system is better than the solvent system in terms of environmental problems and safety.

Japanese Patent Laid-Open Nos. 2000-72879 and 2
JP-A-000-119398 describes an aqueous dispersion of an ethylene-unsaturated carboxylic acid copolymer resin having an unsaturated carboxylic acid content of 5 to 30% by mass, and a method for producing the same, to produce a laminate film. It's easy to do. However, resins with a high unsaturated carboxylic acid content have high polarities, such as polyethylene terephthalate, polypropylene,
Adhesion to films with low polarity such as polyethylene is very weak. Further, since the amount of unsaturated carboxylic acid is large, the resulting coating has almost no alkali resistance.

Polyolefin resins having a low unsaturated carboxylic acid content have relatively good adhesion to films of low polarity. A method for aqueous dispersion of a polyolefin resin having a low unsaturated carboxylic acid content is disclosed in JP-A-62-252.
As disclosed in JP-A-478, JP-A-5-163420, JP-A-7-82423 and JP-A-9-296081, various emulsifiers and protective colloids are used. However, if the system thus contains a highly hydrophilic emulsifier or a compound having a protective colloid action, these remain in the film even after drying, so that the water resistance of the film formed is significantly reduced. There is a problem of doing. Further, a coating film containing an emulsifier or a compound having a protective colloid action is not preferable in terms of environment and hygiene because they may bleed out.

As described above, no technique has been known for thinly laminating a polyolefin resin layer containing no emulsifier or protective colloid and having a low unsaturated carboxylic acid content on a thermoplastic resin film.

[0007]

In order to solve the above problems, the present inventors have found that a polyolefin resin layer having a low unsaturated carboxylic acid content, which does not substantially contain an emulsifier or a compound having a protective colloid action. An object of the present invention is to provide a laminated film in which the above is thinly laminated on a thermoplastic resin film, and which has good hygiene, water resistance, alkali resistance, coating adhesion, and heat sealability.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that by laminating a polyolefin resin having a specific composition on a thermoplastic resin film, excellent hygiene, water resistance, and Alkali resistance, film adhesion,
They have found that they have heat-sealing properties and have reached the present invention. That is, the gist of the present invention is as follows. (1) 0.01 to at least one side of the thermoplastic resin film
A laminate film comprising a layer of the following polyolefin resin having a thickness of 10 μm, wherein the polyolefin resin layer contains substantially no emulsifier component or a compound having a protective colloid action. Polyolefin resin: unsaturated carboxylic acid or its anhydride (A1), ethylene hydrocarbon (A2), the following (I) to (I
V) or at least one compound (A
3) a copolymer composed of and each component (A
A polyolefin resin in which the mass ratio of 1) to (A3) satisfies the following formulas (1) and (2). 0.01 ≦ (A1) / {(A1) + (A2) + (A3)} × 100 <5 (1) (A2) / (A3) = 55/45 to 99/1 (2)

[Chemical 2] (2) The method for producing a laminate film according to (1), which comprises a step of applying the aqueous polyolefin resin dispersion on at least one side of the thermoplastic resin film and then drying the layer when the polyolefin resin layer is provided. (3) When the polyolefin resin layer is provided, it comprises a step of applying the aqueous dispersion of the polyolefin resin to at least one side of the thermoplastic resin film, and then stretching the film in the longitudinal and / or transverse directions (1 The manufacturing method of the laminated body film of description.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The laminate film of the present invention comprises a layer of a polyolefin resin having a characteristic composition provided on at least one side of a thermoplastic resin film.

In the laminate film of the present invention, the above-mentioned polyolefin resin layer having a thickness of 0.01 to 10 μm is provided on at least one side of the thermoplastic resin film.
The method for forming the polyolefin resin layer is not particularly limited, but when considering the economical aspect such as making the thickness of the polyolefin resin layer thin, an aqueous dispersion of a polyolefin resin is applied to a thermoplastic resin film as described below, The method of drying is most preferred. At this time, a step of applying the aqueous dispersion to the thermoplastic resin film and then stretching the film in the machine direction and / or the transverse direction of the film may be performed.

The polyolefin resin layer of the laminate film of the present invention is characterized by containing substantially no emulsifier or compound having a protective colloid action. here,
The term “substantially free of an emulsifier or a compound having a protective colloid action” means, for example, in the process of manufacturing a laminate film (for example, at the time of preparing a coating solution, etc.), these non-volatile substances are used for the purpose of stabilizing the solution. By not positively adding a sexually active agent or compound to the system, it means that the resin layer of the resultant laminate film of the present invention does not contain them. It is particularly preferable that such a compound has a content of zero, but within a range that does not impair the effects of the present invention, the content is 0.1 with respect to the polyolefin resin component.
It does not matter if the content is less than about 10% by mass.

The composition of the polyolefin resin used in the present invention will be described below. The polyolefin resin used in the polyolefin resin layer of the laminate film of the present invention has an unsaturated carboxylic acid or its anhydride (A1) component of 0.01% with respect to the entire resin [(A1) + (A2) + (A3)].
Mass% or more, less than 5 mass%, more preferably 0.1 mass% or more, less than 5 mass%, more preferably 0.5 mass% or more, 5
It is necessary to contain less than 1% by mass, most preferably 1 to 4% by mass. When the content of the component (A1) is less than 0.01% by mass, the adhesiveness with a highly polar film may be reduced. On the other hand, when the content of the unsaturated carboxylic acid or the anhydride thereof is 5% by mass or more, the amount of carboxyl groups increases and the alkali resistance decreases. Furthermore, the polarity of the polyolefin resin becomes high, and the adhesiveness with a film having low polarity may be reduced.

The unsaturated carboxylic acid or its anhydride that can be used as the component (A1) of the polyolefin resin is a compound having at least one carboxyl group or acid anhydride group in the molecule (in the monomer unit), Specific examples thereof include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid and crotonic acid, as well as half esters and half amides of unsaturated dicarboxylic acids. Of these, acrylic acid, methacrylic acid, maleic acid and maleic anhydride are preferable, and acrylic acid and maleic anhydride are particularly preferable.
The unsaturated carboxylic acid may be copolymerized in the polyolefin resin, and the form thereof is not limited, and examples thereof include random copolymerization, block copolymerization, and graft copolymerization.

The polyolefin resin used in the present invention requires the component (A3) represented by any of the following formulas (I) to (IV) as a constituent component, and this component imparts hydrophilicity to the polyolefin resin. Therefore, the (A1) component is
Even if it is less than 5% by mass, it can be made aqueous without adding an emulsifier or a protective colloid. The mass ratio (A2) / (A3) of the ethylene hydrocarbon (A2) component and the (A3) component is
It is necessary to be in the range of 55/45 to 99/1, and 60 / in order to have adhesiveness with various thermoplastic resin films.
It is preferably 40 to 98/2, more preferably 65/35 to 97/3, further preferably 70/30 to 97/3, and more preferably 75/25 to 97/3. Particularly preferred. The ratio of the (A3) component to [(A2) + (A3)] is 1
If it is less than mass%, the adhesiveness to various films will be deteriorated. On the other hand, if the content ratio of the compound (A3) exceeds 45% by mass, the properties of the component (A2) as a polyolefin resin are lost, and the performance such as coating film water resistance and adhesiveness with various films is deteriorated.

[0015]

[Chemical 3]

The ethylene hydrocarbon (A2) component constituting the polyolefin resin used in the present invention is an alkene having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 1-butene, 1-pentene and 1-hexene. And mixtures of these can also be used. Among these, alkenes having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene are more preferable, and ethylene is particularly preferable.

Examples of the component (A3) represented by any of the above formulas (I) to (IV) constituting the polyolefin resin of the present invention include, for example, methyl (meth) acrylate represented by the formula (I), (Meth) acrylic acid esters such as ethyl (meth) acrylate and butyl (meth) acrylate, maleic acid esters such as dimethyl maleate represented by the formula (II), diethyl maleate and dibutyl maleate, and formulas (Meth) acrylic acid amides represented by (III), alkyl vinyl ethers represented by formula (IV) such as methyl vinyl ether and ethyl vinyl ether, vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, versatic Vinyl alcohols such as vinyl acetate and vinyl alcohol obtained by saponifying vinyl esters with a basic compound, And the like, and a mixture thereof can also be used. Among these, the (meth) acrylic acid ester represented by the formula (I) is more preferable, and methyl (meth) acrylate or ethyl (meth) acrylate is particularly preferable.

The polyolefin resin used in the present invention is most preferably a terpolymer composed of ethylene, methyl acrylate or ethyl acrylate, and maleic anhydride. Here, the acrylic acid ester unit may hydrolyze a small part of the ester bond to be converted to an acrylic acid unit when the resin is made water-based, which will be described later. It suffices that the ratio of each constituent component in consideration of the change is within the specified range. Incidentally, unsaturated carboxylic acid anhydride units such as maleic anhydride units constituting the polyolefin resin in the present invention form an acid anhydride structure in which adjacent carboxyl groups are dehydrated and cyclized in a dry state of the resin, In the aqueous medium containing the basic compound, a part or all of the ring is opened to facilitate the formation of the structure of the carboxylic acid or its salt. In the present invention,
When the amount is defined based on the carboxyl group amount of the resin, it is calculated assuming that all the acid anhydride groups in the resin are ring-opened to form a carboxyl group.

In the polyolefin resin used in the present invention, other monomers may be copolymerized in an amount of 20% by mass or less based on the whole resin. For example, methyl vinyl ether, ethyl vinyl ether, etc.
Alkyl vinyl ethers, dienes, (meth) acrylonitrile, vinyl halides, vinylidene halides, carbon monoxide, sulfur disulfide and the like.

The polyolefin resin used in the present invention has a melt flow rate of 0.01 to 500 g / 10 minutes, preferably 1 to 300, at 190 ° C. and a load of 2160 g, which is a measure of the molecular weight.
g / 10 min, more preferably 2-250 g / 10 min, most preferably 2-200 g / 10 min. When the melt flow rate of the polyolefin resin is less than 0.01 g / 10 minutes, it is difficult to obtain an aqueous resin dispersion. on the other hand,
The melt flow rate of polyolefin resin is 500g / 10
If the amount exceeds the limit, the coating film obtained from the aqueous dispersion becomes hard and brittle, and mechanical properties and processability deteriorate.

The method for synthesizing the polyolefin resin used in the present invention is not particularly limited, but it is preferable not to use an emulsifier or a protective colloid. Generally, it is obtained by high-pressure radical copolymerization of a monomer constituting a polyolefin resin in the presence of a radical generator. Further, the unsaturated carboxylic acid or its anhydride may be graft-copolymerized (graft-modified).

The method of using the polyolefin resin aqueous dispersion (hereinafter referred to as "aqueous dispersion"), which is the most preferable method for producing the laminate film of the present invention, will be described in detail below.

The aqueous dispersion preferably used in the present invention has the above-mentioned polyolefin resin having a specific composition dispersed or dissolved in an aqueous medium. Here, the aqueous medium is a medium composed of a liquid containing water as a main component, and may contain a water-soluble organic solvent or a basic compound described later.

The number average particle size of the polyolefin resin particles dispersed in the aqueous dispersion is 1 μm or less from the viewpoint that the storage stability of the aqueous dispersion is improved and the transparency of the laminate film is further improved. It is preferably 0.5 μm or less, more preferably 0.3 μm or less, particularly preferably less than 0.1 μm. The particle size distribution is not particularly limited. These particle sizes can be achieved by the method described below.

The resin content in the aqueous dispersion can be appropriately selected depending on the film forming conditions, the desired thickness and performance of the resin coating film, and is not particularly limited, but the viscosity of the coating composition can be appropriately maintained. From the viewpoint of exhibiting good film forming ability, 1 to 60 mass% is preferable, 3 to 55 mass% is more preferable, 5 to 50 mass% is further preferable, and 5 to 45 mass% is particularly preferable.

Since the resin layer of the laminate film does not substantially contain an emulsifier or a compound having a protective colloid action (hereinafter, collectively referred to as an emulsifier etc.), the aqueous dispersion contains substantially no such emulsifier. It is preferable not to contain it. By using the method disclosed below, a polyolefin resin can be stably dispersed in an aqueous medium without using these. Since emulsifiers and the like are generally non-volatile, if they are used to prepare an aqueous dispersion, they remain in the polyolefin resin layer of the laminate film, have the effect of plasticizing this resin layer, and are water resistant. And so on. On the other hand, since the aqueous dispersion described below does not substantially contain an emulsifier and the like, even when it is formed into a laminated film, it does not contain this, and the performance such as coating properties and water resistance originally possessed by the polyolefin resin is included. Can be maintained.

Examples of the emulsifiers used in the present invention include cationic emulsifiers, anionic emulsifiers, nonionic emulsifiers, and amphoteric emulsifiers. In addition to those generally used in emulsion polymerization, surfactants are also included. For example, as anionic emulsifiers, sulfuric acid ester salts of higher alcohols, higher alkyl sulfonates, higher carboxylates, alkylbenzene sulfonates, polyoxyethylene alkyl sulphates, polyoxyethylene alkyl phenyl ether sulphates, vinyl sulphosuccinates Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyethylene glycol fatty acid ester, ethylene oxide propylene oxide block copolymer, polyoxyethylene fatty acid amide, ethylene oxide-propylene oxide. Examples thereof include compounds having a polyoxyethylene structure such as copolymers, sorbitan derivatives, and the like. , Lauryl dimethylamine oxide, and the like.

As the compound having a protective colloid action, polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, modified starch, polyvinylpyrrolidone, polyacrylic acid and its salts, carboxyl group-containing polyethylene wax, Carboxyl group-containing polypropylene wax,
Number-average molecular weight of carboxyl group-containing polyethylene-propylene wax or the like is usually 5000 or less, acid-modified polyolefin waxes and salts thereof, acrylic acid-maleic anhydride copolymers and salts thereof, styrene- (meth) acrylic acid copolymers , Ethylene- (meth) acrylic acid copolymer,
Isobutylene-maleic anhydride alternating copolymer, (meth) acrylic acid-unsaturated carboxylic acid content such as (meth) acrylic acid ester copolymer 10 mass% or more carboxyl group-containing polymer and salts thereof, polyitaconic acid and Examples thereof include salts, water-soluble acrylic copolymers having an amino group, gelatin, gum arabic, casein and the like, which are generally used as dispersion stabilizers for fine particles.

In the aqueous dispersion used in the present invention, the carboxyl group of the polyolefin resin is preferably neutralized with a basic compound. The electric repulsive force between the carboxyl anions generated by the neutralization prevents aggregation among the fine particles and imparts stability to the aqueous dispersion.

The basic compound used in the aqueous solubilization may be one that can neutralize the carboxyl group. As the basic compound, a compound that volatilizes when forming a film is preferable from the viewpoint of water resistance of the film, and among them, an organic amine compound having a boiling point of 30 to 250 ° C, more preferably 30 to 200 ° C. Boiling point is 30
If the temperature is lower than 0 ° C, the ratio of volatilization at the time of water-solubilization of the resin described later increases, and it becomes difficult to obtain a good aqueous dispersion. When the boiling point exceeds 250 ° C, it becomes difficult to scatter the organic amine compound from the resin film by drying, and the water resistance of the film may deteriorate.

Specific examples of the organic amine compound include triethylamine, N, N-dimethylethanolamine and the like. From the viewpoint of the stability of the aqueous dispersion, the amount of the basic compound added is preferably 0.5 to 3.0 times equivalent, and more preferably 1.0 to 2.0 times equivalent to the carboxyl group in the polyolefin resin.

Further, in order to accelerate the hydration of the polyolefin resin and reduce the dispersed particle size, an organic solvent can be added during the hydration. The amount of organic solvent used is
It is preferably 40% by mass or less in the aqueous medium, more preferably 1 to 40% by mass, further preferably 2 to 35% by mass, particularly preferably 3 to 30% by mass. When the amount of organic solvent exceeds 40% by mass, it cannot be regarded as an aqueous medium substantially. Further, depending on the organic solvent used, the stability of the aqueous dispersion may decrease.

In general, a part of the organic solvent contained in the aqueous dispersion can be distilled out of the system by an operation called stripping, but this operation is also performed in the aqueous dispersion used in the present invention. The amount of the organic solvent in the aqueous dispersion may be appropriately reduced within the above range by 10% by mass or less, and 3% by mass or less is environmentally preferable.

Specific examples of the organic solvent used in the production of the aqueous dispersion include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl. Examples thereof include ethers and ethylene glycol monobutyl ether, and isopropanol is preferable from the viewpoint of low temperature drying property. The organic solvent preferably has a boiling point of 30 to 250 ° C, particularly preferably 50 to 200 ° C. You may use these organic solvents in mixture of 2 or more types. When the boiling point of the organic solvent is lower than 30 ° C., the rate of volatilization at the time of hydration of the resin increases, and the hydration efficiency may not be sufficiently increased. It is difficult for an organic solvent having a boiling point of more than 250 ° C to be scattered from the resin coating by drying,
The water resistance of the coating may deteriorate.

The method for obtaining the polyolefin resin aqueous dispersion from the various components described above is not particularly limited, but for example, the components described above, that is, the polyolefin resin having the specific composition, the basic compound, the organic solvent, and water are preferably used. A method of heating and stirring in an airtight container can be adopted, and this method is most preferable. According to this method
A polyolefin resin having a specific composition can be favorably made into an aqueous dispersion without substantially adding an emulsifier or the like. As the temperature in the container, 60 ~ 200 ℃, preferably 100 ~ 200
It is preferable to stir for 5 to 120 minutes while maintaining the temperature at ℃.

The above-mentioned aqueous dispersion of polyolefin resin is
A film forming property is excellent at room temperature, and a highly transparent film can be formed even at a temperature lower than the melting point of the dispersed resin. Here, the "haze (cloudiness value)" of the coated film coated with the aqueous polyolefin resin dispersion at room temperature is used as a measure of film-forming property and transparency. Haze 2.0 as base material
A PET film of 3.0 to 3.0 (%) is used, and this is dried with a polyolefin resin aqueous dispersion, coated with a coating film thickness of 2 μm, and dried at 25 ° C. The haze of the entire coated film thus obtained is 5.0 (%) or less.

In the polyolefin resin layer of the laminate film of the present invention, the above-mentioned emulsifier component and compound having a protective colloid action are excluded in the range not impairing the effects of the present invention.
It may contain various additives. For example, other polymers, metal salts, inorganic particles, crosslinking agents and the like can be mentioned. Also,
Pigments or dyes such as titanium oxide, zinc oxide and carbon black may be added.

A thermoplastic resin film is used as the base material of the laminate film of the present invention. As the thermoplastic resin film, nylon 6 (hereinafter, Ny6), nylon 6
6, polyamide resin such as nylon 46, polyethylene terephthalate (hereinafter PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, etc. polyester resin, polypropylene (hereinafter PP ), Polyethylene, modified polyethylene (for example, ethylene-vinyl acetate copolymer) and other polyolefin resins, polyimide resins, polyarylate resins, films made of mixtures thereof, or laminates of these films. Among them, PET, Ny6,
PP, polyethylene, polyimide, and polyarylate are preferably used, and particularly PET, Ny6, and PP are preferably used.
Although the three-dimensional structure of the PP resin is not particularly limited, for example,
PP homopolymer having isotactic or syndiotactic and various degrees of stereoregularity, propylene as a main component, and ethylene, 1-butene, 2-butene,
Examples thereof include copolymers with α-olefins such as 1-hexene, 1-heptene and 4-methyl-1-pentene. These copolymers may be multi- or more-dimensional copolymers, and may be random copolymers or block copolymers. Further, it may be a PP that has been acid-modified with maleic anhydride or the like, or a PP that has been subjected to an oxidation treatment at high temperature.
The thermoplastic resin film may be an unstretched film or a stretched film, and the manufacturing method is not particularly limited. Although the thickness of the thermoplastic resin film is not particularly limited, it is usually
It may be 1 to 500 μm.

Next, the method for producing the laminate film of the present invention will be described. The aqueous dispersion obtained by the method described above,
Known film forming method, for example, gravure roll coating,
Reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, brush coating, etc. are used to uniformly coat various base material film surfaces, and the temperature is set near room temperature as necessary. Thereafter, by subjecting it to a drying treatment, it is possible to form a uniform resin coating film by adhering it to the surface of various base material films. As a heating device at this time, an ordinary hot air circulation type oven, an infrared heater or the like may be used. The heating temperature and heating time are appropriately selected depending on the characteristics of the substrate film that is the object to be coated, but in consideration of economic efficiency, the heating temperature is from 30 to the melting point of the film resin. Preferably, 60 to the melting point of the film resin is more preferable, 80 to the film resin is particularly preferable, the heating time is preferably 1 second to 20 minutes, more preferably 5 seconds to 15 minutes, particularly 10 seconds to 10 minutes. preferable.

In the present invention, when the polyolefin resin layer is provided, it is preferable to include a step of applying the aqueous polyolefin resin dispersion on at least one side of the thermoplastic resin film and then stretching the film in the machine direction and / or the transverse direction. To perform coating prior to stretching, first coat an unstretched film, dry it, and then feed it to a tenter type stretching machine to simultaneously stretch the film in the running direction and width direction (simultaneous biaxial stretching), heat treatment, Alternatively, the film may be stretched in the running direction of the film using a multi-stage hot roll or the like, coated, dried, and then stretched in the width direction by a tenter type stretching machine (sequential biaxial stretching). It is also possible to combine stretching in the running direction and simultaneous biaxial stretching in a tenter.

Further, the polyolefin resin layer of the laminate film of the present invention needs to have a thickness of 0.01 to 10 μm.
˜9 μm is more preferable, and 0.03 to 9 μm is particularly preferable.
If the thickness of the resin coating is less than 0.01 μm, the heat sealability deteriorates. On the other hand, when it exceeds 10 μm, the haze of the laminate film becomes high, resulting in poor transparency.

In order to adjust the thickness of the polyolefin resin layer, in addition to appropriately selecting the apparatus used for coating and the conditions of use thereof, the aqueous dispersion having a concentration suitable for the intended thickness of the resin layer is obtained. Is preferably used. The concentration at this time can be adjusted by the composition charged at the time of preparation. Further, the once-prepared aqueous dispersion may be adjusted by appropriately diluting or concentrating it. Furthermore, as described above, the thickness of the layer can be adjusted by stretching the polyolefin resin laminate film.

[0043]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. Various properties were measured or evaluated by the following methods. (1) Constitution of polyolefin resin ¹ H-NMR analysis (manufactured by Varian, 300 MHz) was carried out in orthodichlorobenzene (d ₄ ) at 120 ° C. for determination. (2) Residual amount of ester group after hydration of polyolefin resin After drying an aqueous dispersion of polyolefin resin at 150 ° C, it was placed in ortho-dichlorobenzene (d ₄ ) at 120 ° C for ¹ H-N
MR analysis (manufactured by Varian Co., Ltd., 300 MHz) was performed, and the residual rate (%) of the ester group was determined by setting the amount of the ester group of the (meth) acrylic acid ester before hydration as 100%. (3) Solid Content Concentration of Polyolefin Resin Aqueous Dispersion An appropriate amount of polyolefin aqueous dispersion is weighed and the temperature is set to 150 ° C.
And heat until the mass of the residue (solid content) reaches a constant weight,
The polyolefin resin solid content concentration was determined. (4) Viscosity of polyolefin resin aqueous dispersion The rotational viscosity of the aqueous dispersion at a temperature of 20 ° C was measured using a DVL-BII type digital viscometer (B type viscometer) manufactured by Tokimec. (5) Average particle size of polyolefin resin particles, Microtrack particle size analyzer UPA150 (MODE, manufactured by Nikkiso Co., Ltd.
L No. 9340) was used to determine the number average particle size. (6) The appearance of the aqueous dispersion was visually evaluated. (7) Pot life When the polyolefin resin aqueous dispersion was left at room temperature for 90 days, the appearance of the aqueous dispersion was evaluated according to the following three grades. ○: No change in appearance. Δ: Viscosity increased. X: Solidification, aggregation and generation of precipitates are observed. (8) Content of organic solvent in polyolefin resin aqueous dispersion, Shimadzu Corporation gas chromatograph GC-8A [using FID detector, carrier gas: nitrogen, column packing material (GL Science): PEG-HT ( 5%)-UniportHP (60 /
80 mesh), column size: diameter 3 mm × 3 m, sample charging temperature (injection temperature): 150 ° C., column temperature: 60 ° C., internal standard substance: n-butanol], and the aqueous dispersion or the aqueous dispersion is water. The diluted product was put directly into the apparatus to determine the content rate of the organic solvent. The detection limit was 0.01% by mass. (9) Haze (haze value) According to JIS K7105, "Haze (%)" was measured using NDH2000 "turbidity, haze meter" manufactured by Nippon Denshoku Industries Co., Ltd. The coating film thickness after drying the polyolefin resin aqueous dispersion on the corona-treated surface of a biaxially stretched PET film with a haze of 2.8% (Emblet PET12 manufactured by Unitika Ltd., thickness 12 μm) is 2 μm.
After coating with a Meyer bar so that
It was left to stand in the atmosphere of 3 days and dried to prepare a coated film. The haze of the entire coated film thus produced was measured. (10) Water resistance evaluation method Biaxially stretched PET film (Emblet PET1 manufactured by Unitika Ltd.
2. The polyolefin resin aqueous dispersion was coated on a corona-treated surface having a thickness of 12 μm) with a Meyer bar so that the coating film thickness after drying was 2 μm, and then dried at 100 ° C. for 1 minute. The obtained coated film was left at room temperature for 1 day and then evaluated. The coating film was rubbed several times with a cloth moistened with water, and the state of the coating film was visually evaluated. ○: No change, △: The coating film becomes cloudy, ×: The coating film completely dissolves (11) Alkali resistance evaluation method Biaxially stretched PET film (Emblet PET1 manufactured by Unitika Ltd.)
2, thickness 12μm) and stretched PP film (manufactured by Tohcello Co., Ltd., thickness 20μm) are coated with a polyolefin resin aqueous dispersion on a corona-treated surface using a Meyer bar so that the coating film thickness after drying is 2μm, and then 100 It was dried at ℃ for 1 minute. The obtained coated film was left at room temperature for 1 day and then evaluated. Aqueous solution adjusted to pH 12.0 (20 ℃) with NaOH 65
The coated film was kept at 0 ° C., immersed in this aqueous solution for 3 minutes with stirring, washed with water, and the state of the film was visually evaluated. ○: No change, △: Film is cloudy, ×: Film is dissolved or peeled (12) Adhesion evaluation: Cross-cut / tape peeling Unstretched PET film (120 μm thickness) and Ny6 film (150 μm thickness) The polyolefin resin aqueous dispersion was coated with a Meyer bar so that the coating film thickness after drying was 2 μm, and then dried at 100 ° C. for 1 minute. After leaving the obtained coated film at room temperature for 1 day, JIS K5400 8.
Evaluation was performed according to 5.2. 1 mm x 1 with adhesive tape
mm * 100 cross-cut portions were peeled off and evaluated by the number remaining without peeling. “N / 100” indicates that after the test, n out of 100 grids remained without peeling. (13) Heat sealability evaluation method Corona-treated surfaces and non-corona-treated surfaces of various thermoplastic resin films were coated with a predetermined coating so that the polyolefin resin aqueous dispersion had a predetermined film thickness (described in Examples) after drying. The polyolefin resin coating layer of the polyolefin resin laminate film obtained by coating under the conditions (described in the examples) was brought into contact with the heat press machine (sealing pressure: 0.3 MPa).
For 2 seconds) at 100 ° C and 120 ° C. Cut this sample into a width of 15 mm, and after 1 day, measure the peeling strength of the coating at a pulling speed of 200 mm / min and a pulling angle of 180 degrees using a tensile tester (Intesco Precision Universal Testing Machine 2020) The heat seal strength was evaluated by. The thermoplastic resin film used was biaxially stretched PET.
Film (Unitika Emblet PET12, thickness 12μ
m) Biaxially stretched Ny6 film (Unitika emblem,
Thickness 15μm, Stretched PP film (Tohcello, thickness 20μ
m).

The composition of the polyolefin resin used is shown in Table 1.
Shown in. The melting points of the resins listed in Table 1 are DSC.
It is a value measured by (DSC-7 manufactured by Perkin Elmer),
The melt flow rate is the method described in JIS 6730 (190 ℃, 216
It is a value measured with 0 g load).

[0045]

[Table 1]

(Production of Polyolefin Resin Aqueous Dispersion E-1) 60.0 g of polyolefin resin [Bondayne HX-8290 (a), Sumitomo Chemical Industry Co., Ltd.], 60.0 g of isopropanol (hereinafter IPA), 4.5 g
(For the carboxyl group of maleic anhydride in the resin 1.
8 times equivalent) triethylamine (hereinafter TEA) and 175.
When 5 g of distilled water was charged into a glass container and stirred at a rotating speed of a stirring blade of 300 rpm, no precipitation of resin particles was observed at the bottom of the container, and it was confirmed that the resin particles were in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. And the system temperature is 140-145
The mixture was kept at 0 ° C. and stirred for another 20 minutes. After that, put it in a water bath and cool it to room temperature (about 25 ° C) while stirring it at a rotation speed of 300 rpm, and then pressurize it with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) (air pressure 0.2 MPa).
And milky white uniform polyolefin resin aqueous dispersion E-
Got 1. Various properties of the aqueous dispersion are shown in Table 2. The number average particle diameter was 0.072 μm, the distribution was one peak, and the polyolefin resin was dispersed in the aqueous medium in a good state. Furthermore, the pot life of this aqueous dispersion was 90 days or more. The analysis of the resin composition after hydration revealed that the residual rate of ethyl acrylate was 100%, and the ester group was not hydrolyzed. The ester group residual ratio was 100%, which did not change even after standing for 90 days at room temperature. The haze of the coated film coated with this aqueous dispersion by the method described above was 2.8%, and the transparency was good.

(Production of Polyolefin Resin Aqueous Dispersion E-2) Bondine HX-8210 as a polyolefin resin
(A) Using (Sumitomo Chemical Co., Ltd.), the polyolefin resin aqueous dispersion was prepared in the same manner as in the production of the coating composition E-1 except that the amount of amine with respect to the carboxyl group in the resin was changed as shown in Table 2. Body E-2 is obtained. Various properties of the aqueous dispersion are shown in Table 2. Analysis of the resin composition after hydration revealed that 1% of ethyl acrylate units were hydrolyzed and converted to acrylic acid. That is, the ester group residual ratio was 99%.

(Production of Aqueous Polyolefin Resin Dispersion E-3) Bondine TX-8030 as a polyolefin resin
(C) Using Sumitomo Chemical Co., Ltd., organic solvent (IPA)
Coating agent composition E-1 except that the amount was changed as shown in Table 2.
Aqueous Polyolefin Resin Dispersion E
-3 was obtained. Various properties of the aqueous dispersion are shown in Table 2.

(Production of Polyolefin Resin Aqueous Dispersion E-4) E-1 (250 g) and distilled water (40 g) were charged into a 0.5-liter two-neck round bottom flask, a mechanical stirrer and a Liebig type condenser were installed, and the flask was placed in an oil bath. The aqueous medium was distilled off. When about 95 g of the aqueous medium was distilled off, heating was stopped and the mixture was cooled to room temperature. After cooling, the liquid component in the flask was pressure filtered (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave), and the solid content concentration of the filtrate was measured.
It was 25.8% by mass. Distilled water was added to this filtrate with stirring to adjust the solid content concentration to 25.0% by mass. Various properties of the aqueous dispersion are shown in Table 2. The content of the water-soluble organic solvent in this aqueous dispersion was 0.5% by mass.

(Production of Polyolefin Resin Aqueous Dispersion E-5) As a polyolefin resin, an ethylene-acrylic acid copolymer resin [Primacol 5980I (D), acrylic acid 2
0 mass% copolymer, manufactured by Dow Chemical Co., Ltd.] was used. Using a stirrer equipped with a heater capable of sealing a pressure-resistant 1 liter glass container, 60.0 g of Primacol 5980I, 16.8
g (1.0 to the carboxyl group of acrylic acid in the resin
(Equivalent weight) TEA and 223.2 g of distilled water were charged into a glass container and stirred at a rotation speed of a stirring blade of 300 rpm. No precipitation of resin granules was observed at the bottom of the container, and it became a floating state. Was confirmed. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes.
Then, the temperature in the system was kept at 100 to 105 ° C., and the mixture was further stirred for 20 minutes. After that, put it in a water bath, cool it to room temperature (about 25 ° C) while stirring it at a rotation speed of 300 rpm, and then press-filter (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave), Slightly cloudy aqueous dispersion E-
Got 5. At this time, almost no resin remained on the filter. Various properties of the aqueous dispersion are shown in Table 2.

[0051]

[Table 2]

Example 1 Using the laminate film obtained by coating the obtained polyolefin resin aqueous dispersion E-1 on various thermoplastic resin films, evaluation was carried out according to the evaluation method described above. Incidentally, in the preparation of the sample for heat seal strength measurement, the coating conditions, corona-treated surface of the thermoplastic resin film, after coating with a Meyer bar so that the coating thickness after drying on the non-corona-treated surface is 2μm, 100 It was dried at ℃ for 1 minute.
The evaluation results are shown in Table 3.

Examples 2 to 5 The same evaluations as in Example 1 were carried out except that the polyolefin resin aqueous dispersion used was changed as shown in Table 3. The evaluation results are shown in Table 3.

Comparative Example 1 The same evaluation as in Example 1 was carried out except that the aqueous polyolefin resin dispersion used was changed to E-5. The evaluation results are shown in Table 3.

[0055]

[Table 3]

Example 5 Using an extruder equipped with a T die of PET resin (a slow compression type single screw having a diameter of 75 mm and an L / D of 45), a sheet shape was obtained at a cinder temperature of 260 ° C. and a T die temperature of 280 ° C. The film was extruded onto a chill roll, brought into close contact with a cooling roll whose surface temperature was adjusted to 10 ° C., and rapidly cooled to give an unstretched film having a thickness of 120 μm. Subsequently, the unstretched film was introduced into a gravure roll coater, and the polyolefin aqueous dispersion E-1 was coated so that the coating thickness after drying was 15 μm, and the coated film was dried in a hot air dryer at 80 ° C. for 45 minutes.
Dry for seconds. Next, the film was supplied to a tenter type simultaneous biaxial stretching machine, preheated at a temperature of 100 ° C. for 2 seconds, and then stretched at a temperature of 95 ° C. at a draw ratio of 3 times in the longitudinal direction and 3.5 times in the lateral direction. The transverse relaxation rate was 5%. The coat thickness of the obtained coat film was 1.4 μm. Heat press machine (sealing pressure 0.3M
Pressed at 120 ° C for 2 seconds with Pa). This sample 15
Cut out in mm width, and after 1 day, heat-seal by measuring the peel strength of the coating at a pulling speed of 200 mm / min and a pulling angle of 180 degrees using a tensile testing machine (Intesco Precision Universal Testing Machine 2020) Evaluated for strength. The heat seal strength was 2.3 N / 15 mm. The alkali resistance of the coated film was also good (evaluation: ◯).

Example 6 Using Ny6 resin extruder equipped with T-die (75 mm diameter, slow compression type single screw with L / D of 45), sheet-shaped at a cinder temperature of 260 ° C. and a T-die temperature of 270 ° C. The film was extruded into a sheet, was brought into close contact with a cooling roll whose surface temperature was adjusted to 10 ° C., and was rapidly cooled to obtain an unstretched film having a thickness of 150 μm. Subsequently, the unstretched film was introduced into a gravure roll coater, and the aqueous polyolefin dispersion E-4 was coated so that the coating thickness after drying was 15 μm, and the coated film was dried in a hot air dryer at 80 ° C. for 45 minutes.
Dry for seconds. Next, the film was fed to a tenter type simultaneous biaxial stretching machine, preheated at a temperature of 100 ° C for 2 seconds, and then stretched at 170 ° C at a ratio of 3 times in the longitudinal direction and 3.5 times in the lateral direction. The rate was 5%. The coat thickness of the obtained coat film was 1.4 μm. Heat press machine (sealing pressure 0.3M
Pressed at 120 ° C for 2 seconds with Pa). This sample 15
Cut out in mm width, and after 1 day, heat-seal by measuring the peel strength of the coating at a pulling speed of 200 mm / min and a pulling angle of 180 degrees using a tensile testing machine (Intesco Precision Universal Testing Machine 2020) Evaluated for strength. The heat seal strength was 3.4 N / 15 mm. The alkali resistance of the coated film was also good (evaluation: ◯).

Example 7, Comparative Example 2 The effect of the thickness of the coating layer on the heat seal strength was examined. Biaxially stretched PE of polyolefin resin aqueous dispersion E-1
T film (Emblet PET12 manufactured by Unitika Ltd., thickness 12μ
The m) corona-treated surface and the non-corona-treated surface were coated with a Meyer bar so that the film thickness after drying would be 0.8, 2, 4, 8, and 14 μm, respectively, and then dried at 100 ° C. for 2 minutes. It was pressed at 120 ° C. with a heat press machine (sealing pressure: 0.3 MPa for 2 seconds) so that the polyolefin resin coat layer was in contact with each other. This sample is cut into a width of 15 mm, and one day later, using a tensile tester (Intesco Precision Testing Machine 2020), pulling speed 200 mm / min, pulling angle 18
The heat seal strength was evaluated by measuring the peel strength of the coating at 0 degree. Moreover, the haze was measured. The evaluation results are shown in Table 4.

[0059]

[Table 4]

Examples 1 to 4 were excellent in alkali resistance, adhesiveness and heat sealability. In Examples 5 and 6, in the production of the laminate film of the present invention, an unstretched film was coated with a polyolefin aqueous dispersion and dried, and then this was simultaneously biaxially stretched in the longitudinal and transverse directions.
The properties of the coating were good. In Example 7, the heat seal strength was maintained at a high level even when the thickness of the polyolefin resin layer was changed. In Comparative Example 1, the composition of the polyolefin resin was out of the range of the present invention, so that the alkali resistance and the heat sealing strength were inferior. In Comparative Example 2, when the thickness of the polyolefin resin layer exceeded 10 μm, the heat seal strength was hardly improved and the haze was increased.

[0061]

EFFECT OF THE INVENTION Hygiene, water resistance, alkali resistance, and coating film obtained by thinly laminating a polyolefin resin layer having a low unsaturated carboxylic acid content, which does not substantially contain an emulsifier or a compound having a protective colloid action, on a thermoplastic resin film. It is possible to obtain a laminated film having excellent adhesiveness and heat sealability.

Continued front page    F-term (reference) 4F006 AA12 AA35 AA38 AB13 BA05                       BA11 BA13 BA16 CA07 DA04                       DA05 EA05 EA06                 4F100 AK01A AK03B AK03C AK04B                       AK04C AK04J AK07A AK21B                       AK21C AK21J AK24B AK24C                       AK24J AK25B AK25C AK25J                       AK26B AK26C AK26J AK42A                       AK48A AL01B AL01C BA02                       BA03 BA06 BA07 BA10B                       BA10C EH46 EJ37 EJ55                       GB15 JA06B JA06C JB01                       JB07 JB16A JL00 JL11                       JL12 YY00B YY00C

Claims (7)

[Claims] 1. A laminate film comprising a layer of the following polyolefin resin having a thickness of 0.01 to 10 μm provided on at least one side of a thermoplastic resin film, wherein the polyolefin resin layer is a compound having an emulsifier component or a protective colloid action. A laminate film which is substantially free of. Polyolefin resin: (A1) unsaturated carboxylic acid or anhydride thereof, (A2) ethylene hydrocarbon, (A3) at least one compound represented by any of the following formulas (I) to (IV) A polyolefin resin which is a copolymer having the following formulas (1) and (2) in which the mass ratio of each of the constituent components (A1) to (A3) is satisfied. 0.01 ≦ (A1) / {(A1) + (A2) + (A3)} × 100 <5 (1) (A2) / (A3) = 55/45 to 99/1 (2) [Chemical formula 1] 2. The laminate film according to claim 1, wherein the melt flow rate of the polyolefin resin at 190 ° C. under a load of 2160 g is 0.01 to 500 g / 10 minutes. 3. An unsaturated carboxylic acid or its anhydride (A
The laminated film according to claim 1 or 2, wherein the component 1) is at least one selected from maleic anhydride, acrylic acid and methacrylic acid. 4. The polyolefin resin according to claim 1, which is an ethylene-acrylic acid ester-maleic anhydride terpolymer or an ethylene-methacrylic acid ester-maleic anhydride terpolymer. Laminated film in any one. 5. The laminate film according to claim 1, wherein the thermoplastic resin film is any one of polyethylene terephthalate, nylon 6 and polypropylene. 6. A method for producing a laminate film according to claim 1, wherein the polyolefin resin aqueous dispersion is applied to at least one side of the thermoplastic resin film and then dried when the polyolefin resin layer is provided. A method for producing a laminate film, comprising the steps of: 7. A method for producing a laminate film according to claim 1, wherein the aqueous polyolefin resin dispersion is applied to at least one side of the thermoplastic resin film when the polyolefin resin layer is provided, and then the film is obtained. A method for producing a laminate film, comprising a step of stretching the film in the machine direction and / or the transverse direction.