JP2003182002A - Laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a laminate improved in aqueous ink coating properties and excellent in gas barrier properties and transparency. <P>SOLUTION: The laminate is obtained by laminating an aqueous ink printing layer on at least the single surface of a substrate layer comprising a thermoplastic resin (A) and stretched at least uniaxially through a polyvinyl alcohol polymer layer (C) of which the reduction ratio is not more than 30% when the polymer layer (C) is treated with water at the temperature of 60°C for 15 min. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate containing a polyvinyl alcohol polymer layer having excellent adhesion to a water-based ink printing layer. More specifically, it relates to a laminate suitable for a packaging film for foods, pharmaceuticals, etc., which is excellent in transparency, gas barrier property and water resistance.

[0002]

2. Description of the Related Art Polyolefin films, typified by polypropylene films, are more easily charged than films made of polar polymers such as polyester films and polyamide films. If they are used as they are for packaging films, they may absorb dust in the air. Since almost all the films are likely to block, an antistatic agent is added almost without exception. However, it is known that when printing on a film surface to which an antistatic agent is added, particularly when printing with a water-based ink, the antistatic agent inhibits the adhesion of the water-based ink.

On the other hand, as a transparent gas barrier film, on the surface of a thermoplastic resin film such as biaxially oriented polyester or biaxially oriented polypropylene, a gas barrier property such as polyvinylidene chloride, polyvinyl alcohol or ethylene-vinyl alcohol copolymer is provided. A film coated or laminated with an excellent resin is known. However, when a water-based ink is used when printing a film laminated with such a gas-barrier resin, the polyvinyl alcohol-based polymer has excellent water-solubility, so that the surface thereof is swollen or dissolved by the water contained in the water-based ink. There is a risk that the printing surface will flow.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a laminate excellent in gas barrier property and transparency, which has improved water-based ink coatability, which is a problem of such polyvinyl alcohol polymer laminate. is there.

[0005]

[Means for Solving the Problems]

SUMMARY OF THE INVENTION The present invention has a reduction rate of 30 when treated with water at 60 ° C. for 15 minutes on at least one surface of a base material layer made of a thermoplastic resin (A) and stretched in at least one direction.
% Of the polyvinyl alcohol-based polymer layer (C), the aqueous ink printing layer is laminated on the laminated body.

[0006]

DETAILED DESCRIPTION OF THE INVENTION Thermoplastic Resin (A) The thermoplastic resin (A) used in the substrate layer according to the present invention is
A thermoplastic resin that can be formed into a sheet or a film, such as polyolefin (polyethylene, polypropylene, poly-4-methyl-1-pentene, polybutene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.) , Polyamide (nylon-6, nylon-66, polymethaxylene adipamide, etc.), polyvinyl chloride, polyimide, ethylene / vinyl acetate copolymer, polyacrylonitrile, polycarbonate, polystyrene, ionomer, or a mixture thereof. can do. Of these, polypropylene, polyethylene terephthalate, polyamide and the like are preferable because they have good stretchability and transparency, and particularly polypropylene is water resistant, rigid,
It is preferable because it is excellent in transparency and the like.

Substrate Layer The substrate layer according to the present invention is formed by molding the above-mentioned thermoplastic resin (A) by various known molding methods, for example, a melt molding method such as a T-die method or an inflation method, or a casting method using a solution. The film, sheet or the like is stretched in at least one direction, preferably biaxially. Further, when a material having a water vapor transmission rate of less than 5 g / m ² and further less than 4 g / m ² is used as the base material layer, when used as a packaging material, the outside air (high humidity) and the packaged object side (low humidity) are used. It is preferable that a laminated body having an excellent oxygen barrier property can be obtained even when a difference in humidity occurs. Examples of such a material having a low water vapor transmission rate include a biaxially oriented polypropylene film (OPP film) obtained by adding petroleum resin or the like as a moisture-proof agent, that is, a so-called highly moisture-proof OPP film. As a stretching method, a known stretching method, for example, tenter stretching, tubular stretching, roll stretching,
Rolling drawing, belt drawing, drawing combining these, etc. can be adopted.

Known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, and a colorant are appropriately added to the thermoplastic resin (A) used for the base layer, if necessary. be able to.

Further, at least one surface of the base material layer may be surface-treated or anchor-coated. The surface treatment includes corona discharge treatment, plasma discharge treatment, glow discharge treatment, reverse sputtering treatment, flame treatment, chromic acid treatment, solvent treatment, surface roughening treatment and the like. The anchor coating agent can be composed of various resins such as thermoplastic resin, thermosetting resin, light curable resin and coupling agent.

Polyvinyl alcohol-based polymer The polyvinyl alcohol-based polymer according to the present invention has a homopolymer of vinyl alcohol or an olefin content of 1 to 25 mol%, preferably 3 to 20 mol%, more preferably 5 to 16 mol%. Mol%, preferably 100-300 degree of polymerization
0, more preferably 200 to 2500, most preferably 300 to
It is a polymer containing vinyl alcohol in the range of 2000 as the main component. Within this range, it is easy to form an aqueous solution and coat the base material layer, and the stretchability and gas barrier property are also good. The saponification degree is 90% or more, preferably 95% or more, and the gas barrier property is good in this range. As the olefin, those having 4 or less carbon atoms are preferable, and ethylene, propylene, n-butene, isobutene and the like can be mentioned, but ethylene is most preferable from the viewpoint of water resistance.

In the aqueous solution of the polyvinyl alcohol polymer, a solvent other than water, for example, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, and other diethyl ether, tetrahydrofuran and the like may be added, if necessary. It is also possible to add one kind or a combination of two or more kinds. or,
It is possible to add a wettability improver, an antistatic agent, and various other additives to the polyvinyl alcohol-based polymer within a range that does not impair the characteristics of the present invention.

Polyvinyl alcohol-based polymer layer (C) Polyvinyl alcohol-based polymer layer (C) according to the present invention
Shows a reduction rate of 30 when treated with water at 60 ° C for 15 minutes.
% Or less, preferably 5% or less, more preferably 50% or less, particularly preferably 5% when treated with water at 70 ° C. for 15 minutes. Here, the reduction rate refers to the rate at which the polymer layer (C) is dissolved in warm water and reduced. The polymer layer (C) having such characteristics can be obtained by laminating the polyvinyl alcohol-based polymer on the base material layer and then stretching it in at least one direction, preferably by stretching it 5 times or more.
The stretching temperature is usually 50 to 250 ° C, preferably 100 to 250 ° C.
It is in the range of 200 ° C. Stretching treatment is required to bring the water resistance of the polymer layer (C) to such a range, and even if heat treatment without stretching is performed, the water resistance cannot be brought to such a range. Moreover, it can be confirmed that the melting point (DSC) of the polyvinyl alcohol polymer is increased by 3 to 4 ° C. or more by the stretching treatment. The thickness of the polymer layer (C) is usually 0.01 to 20.0 μm, preferably 0.03 to 15.
The thickness is 0 μm, more preferably 0.05 to 10.0 μm. Within this range, sufficient water resistance and gas barrier properties can be obtained.

The polyvinyl alcohol polymer layer (C) according to the present invention has excellent adhesion to the aqueous ink printing layer even if it is not treated, so that surface treatment is not always necessary, but it has been surface treated or undercoated. Good. The surface treatment includes corona discharge treatment, plasma discharge treatment, glow discharge treatment, reverse sputtering treatment, flame treatment, chromic acid treatment, solvent treatment, surface roughening treatment and the like.

Adhesive Resin (B) As the adhesive resin (B) according to the present invention, various known adhesive resins can be used, but in particular, an ionomer resin or a partially or wholly unsaturated carboxylic acid or the same. A modified polyolefin graft-modified with a derivative is preferred.

Ionomer Resin The ionomer resin according to the present invention is a copolymer of an olefin represented by ethylene and an α, β-ethylenically unsaturated carboxylic acid or a derivative thereof, or an unsaturated carboxylic acid of an olefin polymer or a derivative thereof. It is a graft copolymer of a derivative, and free carboxyl groups in the copolymer are completely or partially neutralized with an alkali metal such as sodium or potassium or an alkaline earth metal such as zinc. These are resins in which all or part of the carboxyl groups are neutralized with a metal such as sodium or zinc. Since the ionomer resin has an ionic group, it has the property of self-dispersing in water when the melt is stirred and mixed in hot water at high speed using a device such as a homomixer, and thus an aqueous dispersion is itself formed. Easy to form.

When such an ionomer resin is used as the adhesive resin layer, it may be a mixture of an ionomer resin and a polyvinyl alcohol polymer. In this case, the ratio of the ionomer resin to the polyvinyl alcohol-based polymer is 100: 0 to 20:80, preferably 100: 0 to 3
0:70, more preferably 100: 0 to 40:60
Is preferable, and in this range, the adhesiveness between the base material layer and the polymer layer (C) is more excellent.

The mixture of the ionomer resin and the polyvinyl alcohol polymer may be a mixture of an aqueous dispersion of the ionomer resin and an aqueous solution of the polyvinyl alcohol polymer.

In the ionomer resin aqueous dispersion or the mixed solution of the ionomer resin aqueous dispersion and the polyvinyl alcohol polymer aqueous solution of the present invention, a solvent other than water, for example, alcohols such as methanol, ethanol and isopropanol, acetone, It is also possible to add one kind or a combination of two or more kinds of ketones such as methyl ethyl ketone and the like, or other diethyl ether, tetrahydrofuran and the like, if necessary.

When an ionomer resin or a mixture of an ionomer resin and a polyvinyl alcohol polymer is used as the adhesive resin, the thickness of the adhesive resin (B) layer is usually 0.01 to 5.0 μm, preferably 0. 01-3.0
[mu] m, more preferably 0.01 to 2.0 [mu] m. Within this range, the adhesiveness is more excellent.

Modified Polyolefin The modified polyolefin of the present invention is obtained by graft-modifying a part or all of the polyolefin with an unsaturated carboxylic acid or its derivative (graft monomer). Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. The unsaturated carboxylic acid derivative is an acid anhydride, ester, amide, imide, metal salt, or the like,
For example, maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,
Butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester, itaconic acid monomethyl ester, itaconic acid diethyl ester, acrylamide, methacrylamide, maleic acid Monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N, N-diethylamide, maleic acid-N-
Monobutylamide, maleic acid-N, N-dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-N-monoethylamide, fumaric acid-N-monobutylamide, fumaric acid-N, N-dibutyrylamide , Maleimide, N-phenylmaleimide, sodium acrylate,
Examples thereof include sodium methacrylate, potassium acrylate, potassium methacrylate and the like. Of these, maleic acid and maleic anhydride are preferred.

As a method of grafting the graft monomer to the polyolefin, various known methods can be adopted. For example, it is carried out by heating the polyolefin and the graft monomer at high temperature in the presence or absence of a solvent, with or without the addition of a radical initiator. Other vinyl monomers such as styrene may be allowed to coexist during the reaction.

The polyolefin as the base of the modified polyolefin is, for example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-pentene, 4-
It is a homopolymer or copolymer of α-olefin such as methyl-1-pentene, and preferably polyethylene or polypropylene. When polypropylene is used as the base material layer, polypropylene is preferred. By using this modified polyolefin, the adhesiveness between the base material layer and the polyvinyl alcohol-based polymer layer (C) is significantly improved. The thickness of the adhesive resin (B) layer is usually 0.1 to 30 μm.
m, preferably 0.1 to 25 μm, more preferably 0.
It is 1 to 20 μm, and the adhesiveness is more excellent in this range.

It is possible to add a wettability improver, an antistatic agent and various other additives to the adhesive resin (B) within a range not impairing the features of the present invention. Also, adhesive resin (B)
The surface of the layer may be surface-treated or anchor-coated. The surface treatment includes corona discharge treatment, plasma discharge treatment, glow discharge treatment, reverse sputtering treatment, flame treatment, chromic acid treatment, solvent treatment, surface roughening treatment and the like. The anchor coating agent can be composed of various resins such as thermoplastic resin, thermosetting resin, light curable resin and coupling agent.

Heat-fusion layer The heat-fusion layer according to the present invention includes ethylene, propylene, butene-1, hexene-1, which are generally known as heat-fusion layers.
Homo- or copolymers of α-olefins such as 4-methyl pentene-1 and octene-1, high-pressure low-density polyethylene, linear low-density polyethylene (so-called LLDPE), high-density polyethylene, polypropylene, polypropylene random copolymer Polyolefin such as polybutene, poly-4-methylpentene-1, low crystalline or amorphous ethylene / propylene random copolymer, ethylene / butene-1 random copolymer, propylene / butene-1 random copolymer Can be used alone or in combination of two or more, ethylene / vinyl acetate copolymer (EVA) or a composition of EVA and polyolefin.

Laminate The laminate of the present invention comprises a polyvinyl alcohol polymer layer (C) having the above-mentioned properties and a water-based ink printing layer on at least one side of the substrate layer having the above-mentioned properties.
In addition, as another embodiment of the laminate of the present invention, a base material layer, an adhesive resin (B) layer, a polyvinyl alcohol polymer layer (C)
And a water-based ink printing layer, and as another aspect, a base material layer,
It is composed of an adhesive resin (B) layer, a polyvinyl alcohol polymer layer (C), a water-based ink printing layer, and a heat-sealing layer.

The thickness of each layer of the laminate of the present invention can be appropriately determined depending on the application, but usually the base material layer is 5 to 500 μm, preferably 5 to 250 μm, and the adhesive resin (B) layer is 0.1.
˜30 μm, preferably 0.1 to 25 μm, more preferably 0.1 to 20 μm, and the polyvinyl alcohol polymer layer (C) is 0.01 to 20 μm, preferably 0.03 to
10 μm, more preferably 0.05 to 10 μm, the heat fusion layer is 0.1 to 30 μm, preferably 0.1 to 25 μm,
More preferably, it is in the range of 0.1 to 20 μm.

When laminating a heat-sealing layer on the laminate of the present invention, the surface of the water-based ink printing layer is coated with various known anchoring agents,
For example, organotitanium-based, polyethyleneimine-based, urethane-based, polybutadiene-based anchoring agents, or laminating adhesives, for example, polyurethane composed of a combination of one- and two-component polyols and polyisocyanates, water-based urethane ionomers and curing agents, etc. Dry laminating adhesives represented by adhesives based on water, water-based dry laminating adhesives composed mainly of acrylic, vinyl acetate, urethane, polyester resins, etc., solventless laminating adhesives represented by polyurethane adhesives, etc. It may be processed in.

Method for Producing Laminate The laminate of the present invention is obtained by applying an aqueous solution of a polyvinyl alcohol polymer on at least one side of a thermoplastic resin (A) film and then stretching it in at least one direction or in two directions. Can be obtained by When stretching in two directions, it can be obtained by simultaneous biaxial stretching. Further, an aqueous solution of a polyvinyl alcohol polymer is applied to at least one surface of the longitudinally stretched thermoplastic resin (A) film, and then,
It can also be obtained by stretching in the transverse direction. As a method for laminating the aqueous ink printing on the polyvinyl alcohol polymer layer (C), various known printing methods can be adopted.

The aqueous solution of the polyvinyl alcohol polymer to be applied may be a solvent other than water, for example, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, or other diethyl ether, tetrahydrofuran and the like, if necessary. It is also possible to use as a solvent dispersion in which one kind or a combination of two or more kinds is added.

After applying the aqueous solution of the polyvinyl alcohol polymer to the thermoplastic resin (A) film, the aqueous solution may be dried at the same time as stretching the thermoplastic resin (A) film. Drying is preferable because it is easy to adjust the drying conditions and the stretching conditions. The drying condition is not particularly limited as long as it is a temperature at which water evaporates, but is usually 50 to 200 ° C, preferably 50 to 180 ° C.
Is the range.

After coating the aqueous solution of the polyvinyl alcohol polymer on the thermoplastic resin (A) film, or
The stretching after coating and drying may be uniaxial stretching or biaxial stretching. As a stretching method, a conventional stretching method, for example, tenter stretching, tubular stretching, roll stretching, rolling stretching, belt stretching, or a combination of these can be applied. Preferably, tenter stretching can be adopted. Various stretching ratios are possible,
In the case of stretching in one direction, it is usually 3 to 15 times, preferably 5 to 15 times. If the stretching ratio is less than 3 times, the effect of improving the water resistance of the polyvinyl alcohol-based polymer may not be sufficiently exhibited, while if it exceeds 15 times, the polyvinyl alcohol-based polymer cannot follow the stretching and causes film cracking. There is a risk. In the case of biaxial stretching, simultaneous biaxial stretching is preferable, and the stretching ratio is usually in the range of 3 to 30 times, preferably 3 to 20 times in terms of surface magnification. If the stretching ratio is less than 3 times, the effect of improving the water resistance of the polyvinyl alcohol-based polymer may not be sufficiently exhibited, while if it exceeds 30 times, the polyvinyl alcohol-based polymer cannot follow the stretching and causes film cracking. There is a risk. If polyvinyl alcohol-based polymer is laminated, and then sequentially biaxially stretched, the polyvinyl alcohol-based polymer can be easily stretched during uniaxial stretching, but the polyvinyl alcohol-based polymer may cause film cracking during biaxial stretching. . The stretching temperature is usually -50 ° C. of the melting point or softening point of the thermoplastic resin of the base material layer to + 50 ° C. of the melting point or softening point of the thermoplastic resin of the base material layer, preferably the thermoplastic resin of the base material layer. Melting point or softening point temperature of
It is in the range of 40 ° C. to the melting point or softening point temperature of the thermoplastic resin of the base material layer + 40 ° C.

As a method for laminating the adhesive resin (B) on the base material layer, various known methods can be adopted. For example, when an aqueous dispersion of an adhesive resin is used, it may be applied onto the base material layer by various known methods. In the case of a resin, the adhesive resin is melted and extrusion coated or extruded on the base material layer. A method of co-extruding the thermoplastic resin used as the base material layer and the adhesive resin may be used.

Various known water-based inks can be used as the water-based ink forming the water-based ink printing layer to be laminated on the polyvinyl alcohol polymer layer (C) of the laminate of the present invention. Such water-based ink is composed of a coloring material which is a pigment and dye consisting of an inorganic pigment, an organic pigment, a vehicle in which a resin is dispersed or dissolved, and a surfactant, an antistatic agent, an antifoaming agent, and an auxiliary agent such as a plasticizer. As a resin, a water-soluble acrylic copolymer resin, a polyester resin, an aqueous polyurethane resin,
A water-based polyamide resin etc. can be illustrated. The water-based ink may contain a small amount, for example, 40% or less of alcohol.

[0034]

INDUSTRIAL APPLICABILITY The laminate of the present invention has water resistance, in particular, an aqueous ink printing layer is laminated on a polyvinyl alcohol polymer layer (C) which is difficult to dissolve even in warm water, and the original characteristics of the polyvinyl alcohol polymer. It has gas barrier properties such as oxygen permeation resistance. Also, the water vapor permeability of the base material layer is 5
The layered product using less than g / m ² is further excellent in gas barrier property under high humidity. Therefore, the laminate of the present invention can be particularly suitably used as a food packaging material in a wide range of fields from foods having a low water activity value to foods having a high water activity value by utilizing such characteristics. Of course, it can be used not only for such food packaging materials but also for pharmaceuticals, industrial materials, electronic materials and the like.

Further, a laminate having an adhesive resin (B) layer made of a modified polyolefin between the base material layer and the polyvinyl alcohol polymer layer (C) has an excellent interlayer adhesive force, and therefore is used as the packaging material. Excellent durability when used.

[0036]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.

The physical properties were measured by the following methods. Measuring method [oxygen permeability] Modern Control Company MOCON O
Using XTRAN2 / 20, 20 ° C 50% RH and 2
It was measured under the conditions of 0 ° C. and 80% RH. [Moisture Permeability] Dry laminate 50 μm LLDPE on the laminated film and add calcium chloride as the content.
A bag is prepared by heat sealing so that the surface area becomes 0.01 m ² . This was left to stand at 40 ° C. and 90% RH for several days, and its moisture absorption amount was measured. [Tape peeling] Cellophane tape (Nichiban cellophane tape) was attached to the surface of the coating layer of the laminated film, and the state of peeling of the coating layer was evaluated by peeling the cellophane tape. ◯: Not peeled Δ: Peeled slightly X: Peeled [Solubility of film] The amount of decrease in the coated film was measured when the film coated with hot water at 60 ° C and 70 ° C was dipped and stirred for 15 minutes. [Melting Point Measurement] The melting point of the coating film was measured with a differential scanning calorimeter (Seiko Instruments DSC220). [Water contact angle] Fully automatic contact angle meter (Kyowa Interface Chemistry CA
-W type) was used to measure the contact angle on the surface of the film. [Printability] Inkability: The spread of each color of the ink transferred from the cell to the laminated film was visually observed, and evaluated in 5 levels. 5 (good) to 1 (poor) Ink adhesion: The adhesiveness between the ink and the film was evaluated by peeling the printing surface with a scotch tape. Those that did not peel between the ink and film were rated as ◯, and those that peeled were rated as x. Blocking: After printing, a roll sample stored at room temperature for 10 days was rewound at 300 m / min for evaluation. The case where no blocking (adhesion between the non-printed surface and the ink) was not observed was rated as ◯.

Example 1 Polypropylene having a melt flow rate of 2.0 g / 10 min was melted in an extruder and extruded in a sheet form from a T die.
An unstretched sheet was obtained. This unstretched sheet was stretched 5 times with a longitudinal stretching machine consisting of a group of heating rolls having different peripheral speeds, and then one side of this longitudinally stretched sheet was subjected to corona discharge treatment. Next, the degree of polymerization is 500 and the ethylene content is 8.5 mol.
%, An aqueous solution of a polyvinyl alcohol-based polymer having a saponification degree of 95% or more is applied to a thickness of 20 μm with a wet film, and then continuously introduced into a tenter transverse stretching machine having a stretching zone setting temperature of 165 ° C. and stretching. Horizontally stretched at a magnification of 10 and 2
A 5μ multilayer film was obtained. In addition, water / alcohol: 1
Using a water-soluble ink (# 3 Zahn cup viscosity 16 seconds) diluted with a 1/1 dilution solvent, 5-color gravure printing was performed to obtain a laminated film. The evaluation results are shown in Tables 1 and 2.

Example 2 A laminated film was obtained in the same manner as in Example 1 except that a polyvinyl alcohol polymer having a polymerization degree of 1000, an ethylene content of 8.6 mol% and a saponification degree of 95% or more was used. . The evaluation results are shown in Tables 1 and 2. The coated polyvinyl alcohol polymer should be peeled off to remove DSC.
The melting point was measured by the method (temperature rising rate 10 ° C./min), and the result was 218.
It was ℃.

Example 3 A laminated film was prepared in the same manner as in Example 1 except that a soluble polyvinyl alcohol polymer having a polymerization degree of 1700, an ethylene content of 6.0 mol% and a saponification degree of 95% or more was used. Got The evaluation results are shown in Tables 1 and 2.

Example 4 The same polypropylene resin as that used in Example 1 was melted in an extruder and extruded in a sheet form from a T die to obtain an unstretched sheet. This unstretched sheet was stretched 5 times with a longitudinal stretching machine consisting of a group of heating rolls having different peripheral speeds, and then one side of this longitudinally stretched sheet was subjected to corona discharge treatment. Next, an aqueous dispersion of an ionomer resin (Mitsui Chemicals Chemipearl S100) was applied as an adhesive resin layer with a wet film to a thickness of 5 μm, dried with warm air, and then the degree of polymerization was further increased to 1000.
With ethylene content of 8.6 mol% and saponification degree of 95%
The above aqueous solution of polyvinyl alcohol polymer was applied with a wet film to a thickness of 20 μm, and then continuously introduced into a tenter transverse stretching machine (set temperature 165 ° C.) and transversely stretched at a stretching ratio of 10 times to form a 25 μ laminated layer. I got a film. Furthermore, water /
Alcohol: A water-soluble ink (# 3 Zahn cup viscosity of 16 seconds) diluted with a 1/1 dilution solvent was used to carry out 5-color gravure printing to obtain a laminated film. The evaluation results are shown in Tables 1 and 2.

Example 5 As an adhesive resin layer, an aqueous dispersion of an ionomer resin (Mitsui Chemicals S100) and a polyvinyl alcohol polymer (polymerization degree of 1000, ethylene content of 8.6 mol%, saponification degree of 95% or more of polyvinyl). A laminated film was obtained in the same manner as in Example 4 except that a mixed solution obtained by mixing an aqueous solution of an alcoholic polymer) with a solid content of 50:50 was used. The evaluation results are shown in Tables 1 and 2.

Example 6 As a polypropylene resin and an adhesive resin layer similar to those used in Example 1, a modified polypropylene graft-modified with maleic anhydride (Mitsui Chemicals Admer QF551) was melted by separate extruders to obtain one unit. In the die, the layers were layered and extruded to obtain an unstretched two-layer sheet. The unstretched sheet was stretched 5 times by a longitudinal stretching machine consisting of a group of heating rolls having different peripheral speeds, and then the modified polyolefin surface of the longitudinally stretched sheet was subjected to corona discharge treatment. Next, the degree of polymerization is 10
00, ethylene content 8.6 mol%, saponification degree 95
% Or more of the polyvinyl alcohol polymer aqueous solution is applied to a thickness of 20 μm by a wet film, and then continuously introduced into a tenter transverse stretching machine (set temperature 165 ° C.) to obtain a stretching ratio of 10
The film was transversely stretched by a factor of 2 to obtain a 25 μ multilayer film. Further, using a water-soluble ink (# 3 Zahn cup viscosity of 16 seconds) diluted with a water / alcohol: 1/1 diluting solvent, 5-color gravure printing was performed to obtain a laminated film. The evaluation results are shown in Tables 1 and 2. Incidentally, when the laminated polyvinyl alcohol-based polymer was treated with water at 60 ° C. and 70 ° C. for 15 minutes, the reduction rate was 0%, that is, it did not dissolve in warm water at all under the above conditions and was 11% with water at 80 ° C. The rate of decrease was shown.

Example 7 A crystalline polypropylene resin (II value: 98.6%) B prepared by blending the same polypropylene resin A as used in Example 1 and petroleum resin (softening point 135 ° C.) and an adhesive resin layer were used. Modified polypropylene (Mitsui Chemicals Admer QF500) C graft-modified with maleic anhydride was melted in different extruders and layered (A / B /
C) and were extruded to obtain an unstretched three-layer sheet. This unstretched sheet was stretched 5 times by a longitudinal stretching machine consisting of a group of heating rolls having different peripheral speeds, and then the C surface of this longitudinally stretched sheet was subjected to corona discharge treatment. Next, polymerization degree 1000
Then, an aqueous solution of a polyvinyl alcohol polymer having an ethylene content of 8.6 mol% and a saponification degree of 95% or more is applied to a thickness of 20 μm with a wet film, and then continuously applied to a tenter transverse stretching machine (set temperature 165 ° C.). And was transversely stretched at a draw ratio of 10 times to obtain a multilayer film. Further, using a water-soluble ink (# 3 Zahn cup viscosity of 16 seconds) diluted with a water / alcohol: 1/1 diluting solvent, 5-color gravure printing was performed to obtain a laminated film. The evaluation results are shown in Tables 1 and 2.

Example 8 A laminated film having a heat-sealing layer was obtained by dry-laminating LLDPE having a density of 0.920 g / cm ³ on the aqueous ink printed layer of the laminated film obtained in Example 4. . The evaluation results are shown in Tables 1 and 2.

Comparative Example 1 A polyvinyl alcohol polymer (Kuraray PVA105) was applied to the corona-treated surface of a 25 μm OPP film having one surface subjected to corona treatment so as to have a thickness of 1.8 μm to obtain a multilayer film. Furthermore, water / alcohol: 1 /
A water-soluble ink (# 3 Zahn cup viscosity of 16 seconds) diluted with the dilution solvent of 1 was used to perform 5-color gravure printing to obtain a laminated film. The evaluation results are shown in Tables 1 and 2.

Comparative Example 2 For the corona treatment of a 25 μm OPP film having a corona treatment on one side, a degree of polymerization of 500, an ethylene content of 8.5 mol% and a degree of saponification of 95% or more are possible and stretchable in water. A soluble polyvinyl alcohol-based polymer was applied to a thickness of 1.8 μm to obtain a multilayer film. Further, using a water-soluble ink (# 3 Zahn cup viscosity of 16 seconds) diluted with a water / alcohol: 1/1 diluting solvent, 5-color gravure printing was performed to obtain a laminated film. The evaluation results are shown in Tables 1 and 2.

Comparative Example 3 The same polypropylene resin as that used in Example 1 was melted in an extruder and extruded in a sheet form from a T die to obtain an unstretched sheet. This unstretched sheet was stretched 5 times with a longitudinal stretching machine consisting of a group of heating rolls having different peripheral speeds, and then,
One side of this longitudinally stretched sheet was subjected to corona discharge treatment, and then polyvinyl alcohol polymer (Kuraray PVA105)
After applying the aqueous solution of the above with a wet film to a thickness of 20 μm,
The film was introduced into a tenter and stretched 10 times to obtain a multilayer film.
Furthermore, using a water-soluble ink (# 3 Zahn cup viscosity 16 seconds) diluted with water / alcohol: 1/1 dilution solvent,
Five-color gravure printing was applied to obtain a laminated film. The evaluation results are shown in Tables 1 and 2.

Comparative Example 4 On a corona-treated surface of a stretched PET film having a thickness of 12 μm, an aqueous isocyanate and a polyvinyl alcohol polymer having a degree of polymerization of 1000, an ethylene content of 8.6 mol% and a saponification degree of 95% or more were formed on a corona-treated surface. The mixed solution at 5:95 was applied so that the nonvolatile content was 1.5 g / m ² . The evaluation results are shown in Tables 1 and 2. In addition, the melting point of the polyvinyl alcohol-based polymer coating film by DSC is 210 ° C. and 60 ° C.
100% reduction after 15 minutes of water treatment,
It was found that under these conditions, the polyvinyl alcohol polymer coat film was completely soluble in warm water.

Comparative Example 5 On a corona-treated surface of a stretched PET film of 12 μm, an aqueous isocyanate in a non-volatile ratio and a polyvinyl alcohol polymer having a polymerization degree of 1000, an ethylene content of 8.6 mol% and a saponification degree of 95% or more were prepared. The mixture mixed at 5:95 is applied so that the nonvolatile content becomes 1.5 g / m ² , and further 1
Heat treatment was performed at 80 ° C. for 3 minutes. The evaluation results are shown in Table 1 and Table 2.
Shown in. The polyvinyl alcohol-based polymer coated film has a melting point by DSC of 210 ° C. and a reduction rate after treatment with water at 60 ° C. for 15 minutes is 90%, that is, the polyvinyl alcohol-based polymer coated film has 90% of the reduction rate under the conditions. Was found to dissolve in warm water.

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[Table 1]

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[Table 2]

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F100 AK01A AK01E AK03A AK03E                       AK07A AK21B AK21C AL04E                       AL07E BA03 BA05 BA06                       BA10B BA10C BA22 EH17                       EH46 EJ37 EJ37A GB15                       GB23 GB66 HB31D HB31E                       JA07B JA07C JB07 JB09D                       JB09E JB16A JD02 JD04A                       JL11E JN01 YY00A YY00B                       YY00C

Claims (9)

[Claims] 1. A polyvinyl alcohol-based material having a reduction rate of 30% or less when treated with water at 60 ° C. for 15 minutes on at least one surface of a base material layer made of a thermoplastic resin (A) and stretched in at least one direction. A laminate comprising a water-based ink printing layer laminated via a polymer layer (C). 2. A polyvinyl alcohol polymer having an olefin content of 1 to 25 mol% and a degree of polymerization of 100 to 300.
The laminate according to claim 1, which is a polyvinyl alcohol-based polymer having 0 and a saponification degree of 90% or more. 3. The method according to claim 1, wherein the base material layer is a biaxially stretched film having a water vapor transmission rate of less than 5 g / m ² , and the polyvinyl alcohol polymer layer (C) is stretched in at least one direction. Stack of. 4. The laminate according to claim 3, wherein the base material layer is a biaxially stretched film having a moisture permeability of less than 5 g / m ² . 5. The laminate according to claim 1, wherein an adhesive resin (B) layer is provided between the base material layer and the polyvinyl alcohol polymer layer (C). 6. The laminate according to claim 5, wherein the adhesive resin (B) layer is formed partially or entirely of a modified polyolefin graft-modified with an unsaturated carboxylic acid or a derivative thereof. 7. A laminate according to claim 1, further comprising a heat-sealing layer laminated on the water-based ink printing layer. 8. The laminate according to claim 1, wherein the thermoplastic resin (A) is a polyolefin. 9. The laminate according to claim 1, wherein the thermoplastic resin (A) is polypropylene.