JP2009061708A - Method for manufacturing gas barrier laminated film, and laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a gas barrier laminated film the laminate strength of which is hardly deteriorated and which has variance-narrow, stable and high gas barrier properties and to provide the laminated film. <P>SOLUTION: The method for manufacturing the gas barrier laminated film, in which gas barrier properties are added to a base material film by the printing work using a photogravure printing press, comprises steps of: printing an anchor coating agent on the whole surface of the base material film in the beginning or middle of the printing work; and printing a gas barrier coating agent on the whole surface of the base material film twice without a break in the middle or end of the printing work. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to the production of a gas barrier laminate film, and particularly relates to a method for producing a gas barrier laminate film that can easily add a high gas barrier property.

  In the case of packaging bags used for packaging foods, pharmaceuticals, etc., the gas barrier layer is used to block the oxygen and water gases that cause them to prevent the contents from being altered or deteriorated due to oxidation or moisture absorption. A composite film provided with is used. The composite film is mainly composed of a plastic film as a base material, a gas barrier layer, a printing layer, and a sealant layer, and various components and processing methods have been studied so that the functions of the respective layers are effectively exhibited. Patent Document 1 contains a printed layer, unmodified polyvinyl alcohol and acetoacetyl group-modified polyvinyl alcohol in a weight ratio (unmodified polyvinyl alcohol / acetoacetyl group-modified polyvinyl alcohol) 95/5 to 10/95 on a substrate. A laminate in which gas barrier layers are sequentially laminated has been proposed.

  In Patent Document 2, a printing ink layer and a gas barrier coating layer can be laminated simultaneously (in-line) on a printing machine, and at least a printing ink layer, a polymer resin, and an inorganic material are formed on a substrate film. There has been proposed a laminate material having a gas barrier property obtained by sequentially laminating a gas barrier coating layer formed by applying a gas barrier composition containing a layered compound as a main component and a sealant film layer having a heat sealing property.

  However, the laminates obtained by these methods have a problem that partial variations in gas barrier properties tend to occur, and it is difficult to stably produce a laminated film having high gas barrier properties.

JP 2004009658 A JP 2005-059329 A

  The present invention provides a method for producing a gas barrier laminate film, which is a gas barrier laminate film, in which a decrease in laminate strength is small and a stable and high gas barrier property without variation is obtained, and the laminate film.

  The main feature of the present invention is that an anchor agent and a coating agent can be printed on the entire surface of a multicolor gravure printing machine in-line to obtain a stable and high gas barrier property and laminate adhesive strength. In particular, it has been found that the gas barrier property does not vary and is greatly stabilized by printing the entire surface of the coating agent twice.

That is, the present invention is (1) a method for producing a gas barrier laminated film in which a coating layer is formed on a base film by gravure printing,
Forming an anchor layer by printing the entire surface of the anchor agent;
A step of forming a coating layer by continuously printing the entire surface of the coating agent twice so that the laminated film has an oxygen permeability of 10 ml / m ² · 24 hrs · MPa or less under conditions of a temperature of 23 ° C. and a humidity of 50% rh. It is related with the manufacturing method of the gas barrier property laminated film characterized by including.

  In the present invention, (2) the coat layer contains polyvinyl alcohol (A) and an inorganic layered compound (B) in a mass ratio (A / B) of 99/1 to 30/70. The present invention relates to a method for producing a gas barrier laminate film.

  The present invention also relates to (3) the method for producing a gas barrier laminate film according to (1) or (2), wherein the anchor agent is a urethane resin or a polyester resin.

  Moreover, this invention relates to the manufacturing method of the gas barrier laminated film in any one of (4) (1)-(3) whose said coating layer is 0.01-2 micrometers.

  Moreover, this invention relates to the manufacturing method of the gas barrier laminated film in any one of said (1)-(4) whose said anchor layer is 0.01-0.5 micrometer.

  The present invention also relates to (6) a gas barrier laminate film obtained by the method for producing a gas barrier laminate film according to any one of (1) to (5) above.

  The present invention also relates to (7) a packaging bag comprising the gas barrier laminate film described in (6) above.

  According to the present invention, an anchor agent and a gas barrier coating agent are printed by a gravure printing machine, and a laminated film having a high gas barrier property with little decrease in laminate strength and small variation in gas barrier property can be obtained.

  Hereinafter, the manufacturing method of the gas barrier laminate film of the present invention will be described in detail.

  The gravure printing machine used in the present invention will be described. The printing press used in the present invention may be a gravure printing press that performs multicolor printing that is usually used. It consists of a number of gravure printing units connected to each other. In the present invention, the anchor agent is printed on the entire surface at the beginning or the middle of the multicolor printing, and then the coating agent is further printed on the entire surface twice in the middle or at the end of the multicolor printing. The printing ink may be printed in any order of the multicolor printing. However, if the ink is printed inline on the coating layer, the coating layer is broken and the barrier property is deteriorated. Therefore, the coating layer is provided on the ink layer.

  Examples of the base film used in the present invention include various plastic films made of polyolefin, modified polyolefin, polyester resin, nylon, polystyrene, etc., which are conventionally used in flexible packaging, and composite films made of two or more of these. These films are preferably surface-treated to improve the adhesion of the ink or anchor agent. Moreover, a transparent vapor deposition film can be used as another base film. In this case, the gas barrier performance can be further enhanced by forming an anchor layer and a coat layer by gravure printing on the vapor deposition surface side. The transparent vapor deposition film is not particularly limited and can be used.

  The printing ink used in the present invention is a gravure ink used in a multicolor printing machine, and a general gravure printing ink can be used. The printing ink can be appropriately selected from general-purpose, anti-boil, anti-retort and the like according to the use of the film. Specifically, for example, natural resins such as shellacs, rosins, rosin-modified maleic acid and derivatives thereof; nitrified cotton and cellulose derivatives such as nitrified cotton and cellulose acetate; polyamide resins; chlorinated rubber, cyclized rubber, etc. Chlorinated rubber and rubber derivatives; vinyl chloride resins such as vinyl acetate vinyl chloride copolymer; polyolefins such as ethylene vinyl acetate copolymer and polypropylene chlorinated products; copolymers of acrylic acid and copolymers of acrylate esters Acrylic resin such as coalescence; Urethane resin; High acid value rosin modified maleic acid resin containing carboxyl group, styrene maleic acid resin, acrylic resin, shellac, casein, acrylic resin or urethane resin emulsion And gravure ink containing resin as a resin component.

  The anchor agent used in the present invention is a solvent-containing resin composition having printing characteristics that can be printed on the entire surface with a gravure printing machine. The anchor agent is used for the purpose of strongly adhering the coating layer to the base film, and the surface of the coating agent is wetted so that the coating agent can be easily wetted and a uniform coating layer can be formed. It can be processed. The anchor agent contains a solvent and a resin, and the resin is dissolved or dispersed in the solvent. As the solvent, an organic solvent type or an aqueous type usually used in gravure printing can be used. The resin is not particularly limited as long as good adhesiveness can be obtained, and examples thereof include a urethane resin and a polyester resin.

  In the gas barrier coating agent used in the present invention, the coating layer at the time of printing and drying contains polyvinyl alcohol (A) and inorganic layered compound (B) in a mass ratio (A / B) of 99/1 to 30/70. . When the mass ratio (A / B) is less than 30, it is difficult to obtain good printability as gravure printing. In addition, in the mass ratio (A / B), when (A) exceeds 99 and (B) is less than 1, the gas barrier effect of the inorganic layered compound is not sufficiently exhibited.

  The gas barrier coating agent, as other components, if necessary, various cross-linking agents such as titanium and isocyanate, silane coupling agents, modifiers such as titanium coupling agents, ultraviolet absorbers, One type or two or more types of antistatic agents, leveling agents, antifoaming agents, coloring agents, and the like can be added.

  A conventionally well-known thing can be used for the polyvinyl alcohol (A) used by this invention, Especially a thing with a polymerization degree of about 1000-2000 is used preferably. When polyvinyl alcohol having a degree of polymerization of 1000 to 2000 is used, a coating agent satisfying both the mechanical strength of the coating layer and the suitability of gravure ink can be obtained.

  The inorganic layered compound (B) used in the present invention refers to a crystalline inorganic compound having a layered structure, and examples thereof include clay minerals represented by kaolinite group, smectite group, mica group and the like. The inorganic layered compound can be selected according to the required quality intended for the type, and can be used alone or in combination of two or more. The smectite group is preferred from the viewpoint that a water-soluble polymer enters between layers of the layered structure and a film in which the layers are enlarged can be easily obtained. Examples of the smectite group include montmorillonite, beidellite, nontronite, hectorite, saponite, soconite, and stevensite. Montmorillonite is particularly preferred from the viewpoint of solution stability, gas barrier development, and printability.

  The inorganic layered compound is used in the form of fine particles. The particulate inorganic layered compound is flat and the planar shape is not limited. The average particle size (average particle size of the planar shape) of the fine particles of the inorganic layered compound is, for example, 0.01 to 2 μm, preferably 0.1 to 2 μm, and more preferably 0.1 to 1 μm. The fine inorganic inorganic layered compound is prepared by dispersing the inorganic layered compound in an aqueous solvent at a high pressure.

  The solvent for the coating agent may be an organic solvent, but is preferably composed of at least an aqueous medium. The aqueous medium may be water and / or a water-soluble organic solvent. That is, the aqueous medium may be water alone, water-soluble organic solvents (for example, alcohols such as methanol, ethanol, isopropanol, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, carbitols, ethers, Ketones such as acetone), or a mixed solvent of water and a water-soluble organic solvent. A water-soluble organic solvent can be used individually or in combination of 2 or more types. Since the aqueous medium to be selected is affected by the stability of the inorganic layered compound and the coating suitability during printing, particularly wettability and drying properties, the present invention may be a mixed solvent of water and a water-soluble organic solvent. preferable. The ratio of water to the water-soluble organic solvent is (water / water-soluble organic solvent) = (30/70) to (98/2), preferably (40/60) to (95/5) in mass ratio. .

  The amount of the solvent used for the coating agent can be selected so that the coating agent can be adapted for gravure printing, and the Zahn cup # 3 viscosity is used for about 10 to 60 seconds. The coating agent used in the present invention is prepared by mixing polyvinyl alcohol, an inorganic layered compound, a solvent, and other additives as required, and dispersing by a wet disperser. Examples of the wet disperser include a bead mill, a ball mill, an attritor, and a jet mill.

  The thickness of the coat layer of the present invention is 0.01-2 μm. When the thickness is less than 0.01 μm, sufficient gas barrier properties are difficult to develop. When the thickness is 2 μm, gas barrier properties are sufficiently developed. When the thickness exceeds 2 μm, odor generation may occur due to coloring due to thickness or residual solvent due to insufficient drying. On the other hand, if the coat layer is too thick, in the measurement of the laminate strength, the coat layer may cause cohesive failure and reduce the adhesive strength.

  The thickness of the anchor layer of the present invention is 0.01 to 0.5 μm. If it is less than 0.01 μm, sufficient adhesion cannot be obtained due to printing defects or the like. An anchor effect of 0.5 μm is sufficient, and if it exceeds 0.5 μm, the residual solvent increases, which is not preferable.

  The transparent vapor deposition film used in the present invention is obtained by vapor-depositing a metal oxide such as silicon oxide or aluminum oxide on a plastic film. If it is a transparent vapor deposition film, it will not specifically limit. Transparent vapor deposition film is prone to cracks and defects in the vapor deposition part due to excessive tension, and when gravure ink printing is performed directly on the vapor deposition layer, it rubs against the hard pigment contained in the ink and causes cracks and defects in the vapor deposition part, resulting in reduced gas barrier properties. It may be a cause. When using a transparent vapor deposition film as a substrate film in the present invention, it is preferable to print the entire surface of the anchor agent at the beginning of gravure printing in order to protect the vapor deposition layer.

  In a laminated film processed with a gravure printing machine and improved in gas barrier properties, a sealant layer is further laminated on the gas barrier coat layer surface. As the sealant layer, a heat-sealing seal material (for example, polyethylene, polypropylene, etc.) used for bag making is used. These films can be produced by a conventional method such as a method of laminating with an adhesive for dry lamination or a method of extrusion laminating with an extruder.

  Using these laminated gas barrier laminated films, bags can be prepared according to various uses such as foods and pharmaceuticals by various bag forming methods. Used as a packaging container that makes good use of gas barrier properties.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

(Oxygen permeability)
Using an oxygen permeability measuring device (manufactured by MOCON, OX-TRAN MODEL 2/21), the oxygen permeability of the laminate in an atmosphere of temperature 23 ° C. and humidity 50% rh is measured. Ten points are randomly measured from the laminated film obtained in the present invention, and the average and variation (standard deviation: σn-1) are calculated.

(Lamination strength)
About the laminated film of the present invention, the width is cut to 15 mm, and T-type peeling is performed at a tensile speed of 300 mm / min with a Tensilon universal type testing machine (RTE-1210 manufactured by A & D Co., Ltd.). Measure. In addition, as a reference sample, a comparative evaluation is made with a laminated film laminated without performing gravure printing (no printing layer or coating layer). The evaluation criteria are as follows.
○ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Deterioration within 10% △ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Deterioration of 10-30% .... Decreased by 30% or more and cannot be used

<Production example; Anchor agent>
As a polyester resin-based anchor agent, a trade name: LG-OX anchor agent A, manufactured by Tokyo Ink Co., Ltd., and a trade name: LG curing agent B, manufactured by Tokyo Ink Co., Ltd. were mixed at a mass ratio of 100/5 to obtain an anchor agent ( Adjust AC1). As urethane-based anchor agent, trade name: LG-OX anchor agent C, manufactured by Tokyo Ink Co., Ltd., and trade name: LG curing agent B, manufactured by Tokyo Ink Co., Ltd. were mixed at a mass ratio of 100/5 to obtain an anchor agent (AC2 ).

<Production example; coating agent>
Polyvinyl alcohol, trade name: PVA-110, manufactured by Kuraray Co., Ltd. (degree of polymerization 1000) is dissolved in a solvent of water / IPA = 80/20 (mass ratio) to 5 mass%, and further, polyvinyl alcohol and montmorillonite. Montmorillonite is mixed so that the mixing ratio (mass ratio) is 80/20 and dispersed by an attritor to obtain the coating agent (C1). The average particle diameter of montmorillonite in the obtained coating agent is 0.5 μm, and the Zahn cup # 3 viscosity is 18 seconds. A coating agent (C2) is obtained in the same manner as in the preparation of the coating agent C1 except that the product name: PVA-117, manufactured by Kuraray Co., Ltd. (polymerization degree 1700) is used as the polyvinyl alcohol. The average particle diameter of montmorillonite in the obtained coating agent is 0.5 μm, and the Zahn cup # 3 viscosity is 23 seconds. In addition, the average particle diameter of the inorganic stratiform compound in the coating agent was measured using a particle size distribution measuring device: Microtrac UPA-150, manufactured by Nikkiso Co., Ltd.

(Example 1)
Using a gravure printing machine on the base material of an OPP (stretched polypropylene) film having a thickness of 20 μm, the anchor agent AC1 is printed on the entire surface, the coating agent C1 is printed on the entire surface, and the coating agent C1 is printed on the entire surface. Formed. Thereafter, a CPP (unstretched polypropylene) film having a thickness of 30 μm was bonded to the coat layer by dry lamination using a polyurethane-based adhesive, and oxygen permeability and laminate strength were measured using the obtained laminated film. Table 1 shows the results of the thickness, oxygen permeability and laminate strength of the anchor layer and the coat layer. The thicknesses of the anchor layer and the coat layer were calculated by a weight method with the specific gravity of each layer being 1. The other examples and comparative examples are similarly shown in Table 1 or Table 2.

(Example 2)
In gravure printing, a laminated film was obtained in the same manner as in Example 1 except that urethane gravure ink was printed between the anchor agent and the coating agent.

(Examples 3 to 6)
In gravure printing, a laminated film was obtained in the same manner as in Example 1 except that the coating agent was printed so as to have the coating layer thickness shown in Table 1.

(Example 7)
A laminated film was obtained in the same manner as in Example 1 using AC2 instead of the anchor agent AC1.

(Comparative Examples 1-5)
A laminated film was obtained in the same manner as in Example 1 except that printing was performed so that the anchor layer thickness, coat layer thickness, and printing ink used in Table 2 were used.

  In Comparative Examples 1 and 4, the laminate strength is inferior because the anchor agent is not used or is small. Comparative Examples 2 and 3 are examples in which the coating agent is printed once, and the variation in oxygen permeability is large. Comparative Example 5 is an example in which the coat layer is too thick. In the measurement of the laminate strength, the coat layer is coherently broken, resulting in a decrease in strength.

  As shown in Tables 1 and 2, the variation in oxygen permeability of the laminated film obtained by printing the anchor agent and the coating agent twice is surely improved, and a decrease in the laminate strength is suppressed.

  The present invention can be used as a method for producing a laminated film having excellent gas barrier properties. In particular, the present invention can be used for a gas barrier laminated film applicable to packaging use for foods, pharmaceuticals, and the like and a method for producing the same.

Claims (7)

A method for producing a gas barrier laminate film in which a gas barrier coat layer is formed by gravure printing on a base film,
Forming an anchor layer by printing the entire surface of the anchor agent;
A step of forming a coating layer by continuously printing the entire surface of the coating agent twice so that the laminated film has an oxygen permeability of 10 ml / m ² · 24 hrs · MPa or less under conditions of a temperature of 23 ° C. and a humidity of 50% rh. A method for producing a gas barrier laminate film, comprising:   The said coating layer is a manufacturing method of the gas barrier laminated film of Claim 1 which contains polyvinyl alcohol (A) and an inorganic layered compound (B) by mass ratio (A / B) 99/1-30/70.   The method for producing a gas barrier laminate film according to claim 1 or 2, wherein the anchor agent is a urethane resin or a polyester resin.   The method for producing a gas barrier laminate film according to any one of claims 1 to 3, wherein the coat layer is 0.01 to 2 µm.   The method for producing a gas barrier laminate film according to any one of claims 1 to 4, wherein the anchor layer is 0.01 to 0.5 µm.     A gas barrier laminate film obtained by the method for producing a gas barrier laminate film according to any one of claims 1 to 5.   A packaging bag comprising the gas barrier laminate film according to claim 6.