JP2020131139A - Conveying device for base material film and method of manufacturing gas barrier film using the same base material film - Google Patents

Abstract

To provide a conveying device for a base material film and a method of manufacturing a gas barrier film using the base material film having an excellent gas barrier property, free from occurrence of blocking, and capable of reducing defects of gas barrier layers caused by an anti-blocking agent.SOLUTION: A conveying device for conveying a base material film including an anti-blocking agent comprises: an unwinding part having an unwinding roll for unwinding the base material film; a winding part having a winding roll for winding the base material film; and 20 or more guide rolls arranged between the unwinding part and the winding part. The base material film is conveyed at a speed of 200 m/min or more between the unwinding part and the winding part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a film used as a packaging material, and more particularly to a method for producing a gas barrier film having anti-blocking property and gas barrier property, and a transport device for transporting the gas barrier film.

In the packaging materials used for packaging foods and pharmaceuticals, water vapor, oxygen, and other gases that alter the contents enter in order to suppress deterioration and putrefaction of the contents and maintain their functions and properties. It is necessary to have the property of blocking water vapor (gas barrier property).

Conventionally, these packaging materials have been used as a gas barrier film by providing a gas barrier layer on a base material such as a film or paper by a film forming technology such as a sputtering method, a vapor deposition method, a wet coating method or a printing method.

In the process of manufacturing a gas barrier film, if the base material, which is a material, has low slipperiness, the handling property at the time of coating the barrier layer is not sufficient, which causes blocking to occur in the film in the film forming line. Since the packaging material in which blocking has occurred must be discarded, there are problems such as an increase in material cost due to an increase in material loss and a decrease in yield.

In order to improve the slipperiness of the packaging material, it is necessary to change the surface free energy of the packaging material. As a method of changing the surface free energy of the packaging material, for example, there is a method of imparting an uneven shape to the surface of the packaging material to reduce the contact area. In addition, as another method, a method of adding a slip agent capable of lowering the surface free energy, a method of using a highly rigid material in order to reduce energy loss when the substance is deformed or to not increase the surface area at the time of contact. Can be mentioned.

The configuration in which an anti-blocking agent is added to the film surface layer in order to impart slipperiness by utilizing the surface unevenness prevents blocking by defining the surface roughness and the number of surface protrusions, as in Patent Documents 1 and 2, for example. Documents have been reported that it can be done.

Japanese Unexamined Patent Publication No. 2001-9983 Japanese Unexamined Patent Publication No. 2001-48994

However, in the methods according to Patent Documents 1 and 2, a uniform coating film cannot be formed with a structure in which the thickness of the barrier layer is thin, the barrier property becomes insufficient, and a sufficient balance between blocking property and barrier property has been established. Absent.
Further, when the gas barrier layer is applied, coating defects due to the anti-blocking agent contained in the film may occur. It is considered that the particles of the anti-blocking agent on the film surface fall off when the gas barrier layer is applied, and the portion becomes a defect.

The present invention has been made in view of the above circumstances, and is an apparatus for transporting a base film, which has excellent gas barrier properties, does not cause blocking, and reduces defects in the gas barrier layer caused by an anti-blocking agent. An object of the present invention is to provide a method for producing a gas barrier film using a base film.

The invention according to claim 1 is
A transport device for transporting a base film containing an anti-blocking agent, the unwinding portion having a unwinding roll for unwinding the base film, and a winding portion having a winding roll for winding the base film. It is provided with 20 or more guide rolls arranged between the unwinding portion and the winding portion, and the base film has a speed of 200 m / min or more between the unwinding portion and the winding portion. It is a transport device characterized by transporting.

The invention according to claim 2 is
The transport device according to claim 1, further comprising a printing unit for forming a gas barrier layer on the base film and a mechanism for heating and drying the base film.

The invention according to claim 3 is
The transport device according to claim 2, wherein the printing unit has a wet coating mechanism.

The invention according to claim 4 is
A method for producing a gas barrier film, which is a step of bringing a base film made of a plastic material containing an anti-blocking agent into contact with 20 or more guide rolls at a transport speed of 200 m / min or more, and at least one of the base materials. It is a method of manufacturing a gas barrier film including a step of forming a gas barrier layer on a surface.

The invention according to claim 5 is
The method for producing a gas barrier film according to claim 4, wherein the antiblocking agent is any one of silica, talc, diatomaceous earth, and an acrylic polymer.

The invention according to claim 6 is
The method for producing a gas barrier film according to claim 4 or 5, wherein the gas barrier layer contains a water-soluble polymer and an inorganic layered mineral as main components.

INDUSTRIAL APPLICABILITY According to the present invention, a device for transporting a base film, which has excellent gas barrier properties, does not cause blocking, and reduces defects in the gas barrier layer due to an antiblocking agent, and a gas barrier film using the base film are provided. Can be done.

It is the schematic which showed the structure of the transfer apparatus of the base film which concerns on embodiment of this invention. It is the schematic which showed the structure of the printing apparatus used in the manufacturing method of the gas barrier film which concerns on embodiment of this invention. It is the schematic sectional drawing which showed the structure of the gas barrier film which concerns on embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. It should be noted that the present embodiment is specifically described in order to better understand the gist of the invention, and is not limited to the present invention unless otherwise specified.

FIG. 1 is a schematic view showing a basic configuration of a base film transport device 10 according to an embodiment of the present invention.

(Transport device)
As shown in FIG. 1, the transport device 10 has a configuration in which the web-shaped base film 1 is transported from the unwinding roll 2a to the winding roll 2c via the guide roll 3 by a roll-to-roll method. There is. The guide roll 3 guides the base film 1 so as to be conveyed by a predetermined route, and supports the base film 1 so as not to be displaced or bent. Further, the transfer device 10 includes a mechanism (not shown) for controlling the transfer speed.

At this time, it is preferable that 20 or more guide rolls 3 are installed between the unwinding roll 2a and the winding roll 2c, and it is more preferable that the transport speed of the base film is 200 m / min or more.

With such an apparatus mode, it is possible to intentionally remove the anti-blocking agent present on the surface of the base film. This makes it possible to suppress coating film defects caused by the anti-blocking agent when forming the gas barrier layer on the base film in a later step. This will be explained in detail later.

(Printing equipment)
As shown in FIG. 2, the printing apparatus 20 includes a printing unit that conveys a web-shaped base film by a roll-to-roll method and continuously coats a coating agent for forming a gas barrier layer. It has a configuration. Further, the unwinding portion and the winding portion have the same configurations as those of the above-mentioned transport device 10.

Specifically, the base film 1 is unwound from the unwinding roll 2a of the unwinding portion and conveyed to the printing portion, and the coating agent 4 is applied onto the base film 1 by the printing roll 2b of the printing portion to form a gas barrier layer. The film is wound by heating and drying while passing through an oven 5 having a heating mechanism, and then the film laminated on the winding roll 2c of the winding portion is wound.
Further, a plurality of guide rolls 3 that come into contact with the film and rotate are provided in the path during the transportation of the base film 1. The guide roll 3 is provided along the film transport path in the entire process from unwinding to winding of the base film 1, and in the process upstream from the printing portion (unwinding portion side), 20 or more guide rollers 3 are provided. 3 is installed.

FIG. 3 shows a layer structure as an embodiment of the gas barrier film. The gas barrier film 30 is formed by laminating the gas barrier layer 12 on one surface of the base film 11, for example, by using the above-mentioned printing apparatus. Hereinafter, the materials and the like of each layer will be described in detail.

(Base film)
The base film 11 is made of a plastic material, for example, a polyolefin resin such as poly C _{2 to 10} such as polyethylene, polypropylene, and a propylene-ethylene copolymer, a polyester resin such as polyethylene terephthalate and polybutylene terephthalate, and nylon 6. Polyamide-based polyamides such as nylon 66, polyamide-based resins such as aromatic polyamides such as polymethoxylylen adipamide, polystyrene, polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl alcohols, ethylene-vinyl alcohol copolymers Examples thereof include vinyl resins such as vinyl resins such as, polymethyl methacrylate, acrylic resins such as (meth) acrylic monomers such as polyacrylonitrile alone or copolymers, and films made of cellophane and the like. These resins are used alone or in combination of two or more.

Among these, a polyolefin-based resin film (particularly, a polypropylene film or the like), a polyester-based resin film (particularly, a polyethylene terephthalate-based resin film), a polyamide-based resin film (particularly, a nylon film), or the like is preferably used.

The base film 11 has at least an anti-blocking agent such as silica, talc, diatomaceous earth, and an acrylic polymer added to the surface. By selecting the type of anti-blocking agent and its particle size, it is possible to develop minute irregularities on the surface of the base film, prevent blocking, and improve processability.
Further, the base film 11 may be provided with additives such as fillers, surfactants, and antistatic agents such as metal oxides, depending on the purpose.

As the base film 11, a single-layer film composed of a single resin or a single-layer or multilayer film using a plurality of resins is used. Further, a laminated base material in which the above resin is laminated on another base material (metal, wood, paper, ceramics, etc.) may be used.

Further, the base film 11 may be an unstretched film, a uniaxially or biaxially stretched oriented film, or a film that has been surface-treated (corona discharge treatment, etc.) or anchor-coated or undercoated. Good. Further, the base film may be a laminated film in which a plurality of resins, metals and the like are laminated.

Further, the base film 11 has good wettability to the coating agent and adhesive strength to the film by subjecting the surface to be coated (the surface forming the film (gas barrier layer or the like)) to corona treatment, low temperature plasma treatment or the like. And may be improved.

The thickness of the base film 11 is not particularly limited, and is appropriately selected according to the price and application while considering the suitability as a packaging material and the suitability for laminating other films, but it is practically used. It is 3 μm to 200 μm, preferably 5 μm to 120 μm, and more preferably 10 μm to 100 μm.

(Film manufacturing method)
A gas barrier film is formed by applying the gas barrier layer to the base film using the apparatus having the configuration shown in FIG. 2. At this time, the anti-blocking agent is added to the surface of the base film. The applied gas barrier layer may have defects due to the particles of the antiblocking agent.

Therefore, in the method for producing the gas barrier film of the present invention, it was decided to transport the base film at a transport speed of 200 m / min or more. At this time, the base film comes into contact with at least 20 guide rolls upstream of the printing portion to which the gas barrier layer is applied. That is, it is preferable that 20 or more guide rolls are provided between the unwinding portion and the printing portion.

By doing so, each time the base film comes into contact with each guide roll, the protrusions due to the particles of the anti-blocking agent contained on the base film surface gradually fall off from the film surface due to friction or impact at the time of contact. Therefore, the protrusions of the anti-blocking agent that may cause coating defects are reduced at the stage immediately before the application of the gas barrier layer.
By applying a gas barrier layer in the printed portion to the base film having reduced protrusions in this way, a uniform barrier layer can be formed and good gas barrier properties can be obtained.

The device for transporting the base film may be any device that has a transport mechanism capable of transporting 20 or more guide rolls and a transport speed of 200 m / min or more and can wind the base film, and the application and the number of devices thereof. , Components, printing method, etc. are not particularly limited. Typical printing devices include roll coaters, gravure coaters, reverse coaters, die coaters, screen printing machines, spray coaters, and the like.

The gas barrier layer can be formed by applying a coating agent on one side (one side) or both sides of the base material to form a coating film, and drying the coating film (removing the aqueous medium).
As a coating agent coating method, it is preferable to use a wet coating method. Known wet coating methods include roll coating, gravure coating, reverse coating, die coating, screen printing, spray coating and the like.

As a method for drying the coating film made of the coating agent, known drying methods such as hot air drying, hot roll drying, and infrared irradiation can be used. The drying temperature of the coating film is preferably, for example, 50 to 200 ° C. The drying time varies depending on the thickness of the coating film, the drying temperature, and the like, but is preferably 1 second to 5 minutes, for example.

(Gas barrier layer)
The gas barrier layer is a layer formed from a specific coating agent. The coating agent preferably contains the water-soluble polymer (A) described below and the inorganic layered mineral (B) as main components.

The water-soluble polymer (A) is not particularly limited as long as it is a compound capable of penetrating between the unit crystal layers of the inorganic layered mineral (B) described later and coordinating (intercalating).
"Water-soluble polymer" refers to a polymer that is soluble in water. The term "dissolution" as used herein refers to a state in which a polymer as a solute is dispersed in water as a solvent at the molecular chain level to form a uniform system.
More specifically, it refers to a state in which the intermolecular force with water molecules is stronger than the intermolecular force between molecular chains of a polymer chain, the entanglement of the polymer chains is disentangled, and the polymer chains are uniformly dispersed in water.

Specific examples of the water-soluble polymer (A) include polyvinyl alcohol resins such as polyvinyl alcohol and derivatives thereof; polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid or esters thereof, salts and copolymers thereof, and polyhydroxy. Vinyl-based polymers such as ethyl methacrylate and its copolymers; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; copolymers containing oxidized starch, etherified starch, starches such as dextrin, and polar groups such as sulfoisophthalic acid. Examples thereof include urethane-based polymers and functional group-modified polymers in which the carboxyl groups and the like of these various polymers are modified.

The water-soluble polymer (A) preferably has a degree of polymerization of 200 or more in consideration of the film cohesive strength. Further, the water-soluble polymer (A) contained in the coating agent may be one kind or two or more kinds.

The water-soluble polymer (A) preferably contains at least one polyvinyl alcohol resin selected from the group consisting of a polyvinyl alcohol-based polymer and a derivative thereof, and has a saponification degree of 95% or more and a degree of polymerization of 300 or more. It is more preferable to contain the polyvinyl alcohol resin of. The degree of polymerization of the polyvinyl alcohol resin is preferably 300 to 2400, more preferably 450 to 2000.

The higher the degree of saponification and the degree of polymerization of the polyvinyl alcohol resin, the lower the hygroscopic swelling property. If the degree of saponification of the polyvinyl alcohol resin is less than 95% or the degree of polymerization of the polyvinyl alcohol resin is less than 300, sufficient gas barrier properties may not be obtained. If the degree of polymerization of the polyvinyl alcohol resin exceeds 2400, the viscosity of the coating agent increases, it is difficult to mix it uniformly with other components, and there is a risk of causing problems such as a decrease in gas barrier property and adhesion strength.

The "inorganic layered mineral" refers to an inorganic compound in which ultrathin (for example, 10 to 500 nm thick) unit crystal layers are overlapped to form one layered particle. The inorganic layered mineral (B) is used for the purpose of further enhancing the gas barrier property of the gas barrier layer.

As the inorganic layered mineral (B), a compound having both or one of the properties of swelling and cleavage in water is preferable, and among these compounds, a clay compound having swelling property to water is particularly preferable. More specifically, the inorganic layered mineral (B) is preferably a clay compound in which water is coordinated between ultrathin unit crystal layers and has both absorption and swelling properties, or one of the properties. Such clay compounds are generally, _Si ^{4 +} is _{O 2} ^- and the layer constituting the coordinated with tetrahedral structure with respect ^{_{to, Al 3 +, Mg 2 +}} , Fe 2 +, Fe 3 + and the like, O ₂ ^- and OH ^- is a layer constituting the coordinated to octahedral structure with respect to, attached at the 1-to-1 or 2-to-1 is a compound which forms a layered structure stacked. This clay compound may be a natural compound or a synthesized compound.

Typical examples of the inorganic layered mineral (B) include hydrous silicates such as phyllosilicate minerals, and for example, kaolinite clay minerals such as halloysite, kaolinite, enderite, dikite, and nacrite; anti Anti-Golite clay minerals such as golite and chrysotile; Smectite clay minerals such as montmorillonite, biderite, nontronite, saponite, hectolite, soconite and stebunsite; vermiculite clay minerals such as vermiculite; white mica, gold mica, Mica or mica clay minerals such as margarite, tetrasilic mica, teniolite; etc. may be mentioned. These inorganic layered minerals (B) are used alone or in combination of two or more.
Among these inorganic layered minerals (B), smectite clay minerals such as montmorillonite and mica clay minerals such as water-swellable mica are particularly preferable.

The size of the inorganic layered mineral (B) is preferably such that the average particle size is 10 μm or less and the thickness is 500 nm or less. When the average particle size and the thickness are each equal to or less than the above upper limit values, the inorganic layered mineral (B) is likely to be uniformly aligned in the gas barrier layer formed from the coating agent, and the gas barrier property and the film cohesive strength are high. It becomes.
If necessary, the coating agent of the present invention may further contain various additives as long as the gas barrier property and the strength as a packaging material are not impaired.

Additives include, for example, reactive curing agents such as polyisocyanates, carbodiimides, epoxy compounds, oxazolidone compounds, and aziridine compounds, antioxidants, weather resistant agents, heat stabilizers, lubricants, crystal nucleating agents, ultraviolet absorbers, and plastics. Examples thereof include agents, antistatic agents, colorants, fillers, surfactants, silane coupling agents and the like.

The content of the water-soluble polymer (A) contained in the gas barrier layer is preferably 25 to 80% by mass, more preferably 30 to 75% by mass, and further preferably 35 to 70% by mass with respect to the total mass of the gas barrier layer. preferable. When the content of the water-soluble polymer (A) is at least the above lower limit value, the inorganic layered mineral (B) is likely to be dispersed. When the content of the water-soluble polymer (A) is not more than the above upper limit value, it is easy to make the dispersion of the inorganic layered mineral (B) uniform.

The content of the inorganic layered mineral (B) contained in the gas barrier layer is preferably 3 to 20% by mass, more preferably 5 to 16% by mass, still more preferably 7 to 12% by mass, based on the total mass of the gas barrier layer. .. When the content of the inorganic layered mineral (B) is at least the above lower limit value, the gas barrier property of the gas barrier layer is likely to be improved. When the content of the inorganic layered mineral (B) is not more than the above upper limit value, the flexibility of the gas barrier layer is likely to be improved.

The coating thickness of the gas barrier layer is set according to the required gas barrier property, but is preferably 0.2 μm to 5 μm, more preferably 0.3 μm to 2 μm. When the coating film thickness is at least the above lower limit value, gas barrier properties can be easily obtained, but the drying load and the manufacturing cost increase. When the coating film thickness is not more than the above upper limit value, it becomes difficult to form a uniform coating film layer, and the influence of barrier deterioration due to protrusions on the surface of the gas barrier layer tends to increase.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

<Material used>
(Base film)
Substrate 1: Biaxially stretched polypropylene film (trade name: VPH2011, thickness 20 μm, manufactured by AJ Plast)
Base material 2: Biaxially stretched polypropylene film (trade name: TITIV, thickness 18 μm, Max
(Manufactured by Speciality Films Limited)
(Coating agent for gas barrier layer)
Water-soluble polymer (A): Polyvinyl alcohol having a saponification degree of 98 to 99% and a degree of polymerization of 1000 (trade name: Poval PVA-110, manufactured by Kuraray Co., Ltd.)
Inorganic layered mineral (B): Water-swellable synthetic mica (trade name: NTS-5, manufactured by Topy Industries, Ltd.)

<Evaluation method>
(Oxygen permeability)

For the gas barrier film of each example, using an oxygen permeability measuring device (OXTRAN-2 / 20 manufactured by MOCON), the oxygen permeability (cm ³ / (m ² · day ·) was used in an atmosphere of 30 ° C. and a relative humidity of 60%. MPa))) was measured.

(Blocking resistance)
The gas barrier film of each example was cut into a size of 50 × 50 mm, and 6 sheets were stacked and stored for 48 hours under a load of 200 kg and 50 ° C. using a permanent strain tester (CO-201 manufactured by Tester Sangyo). After that, the blocking resistance was judged as ◯ if blocking did not occur, and as x if the films were stuck to each other and blocked.

(Number of irregularities on the surface)
For the gas barrier film of each example, the height and dent of the protrusion were measured using a 3D measurement laser microscope (LENT OLS4000 manufactured by OLYMPUS) under the following conditions. Those having a height of 0.2 μm or more between the apex and the flat surface of the protrusion were determined to be protrusions, and those having a depth of 0.2 μm or more between the apex and the flat surface of the recess were determined to be dents.
-Lens: Objective lens, Magnification 50x (MPLAPONLEXT50)
-Measurement area: 514 μm x 1285 μm
・ Filter: Surface correction ・ Mode: Measure the height of the apex of the protrusion and the flat surface in the profile mode.

[Example 1]
The water-soluble polymer (A) and the inorganic layered mineral (B) are blended so that the solid content ratio (A): (B) is 90:10, heated at 80 ° C., mixed, and then at room temperature (30). The mixture was cooled to (° C.) and diluted with ion-exchanged water and isopropanol so that 10% by mass in the total water-soluble medium solvent was isopropanol and the final solid content concentration was 9% by mass to prepare a coating agent.

The base film 1 was used as the base film, and the corona-treated surface of the base film was passed through at a speed of 300 m / min using a gravure coater so that the film thickness after drying was 0.5 μm by the gravure coater. The prepared coating agent was applied and dried by passing through an oven at 90 ° C. for 10 seconds to form a gas barrier layer, and a gas barrier film of Example 1 was obtained. At this time, the number of contact guide rolls before printing was 90.

[Example 2]
A gas barrier film was produced in the same manner as in Example 1 except that the number of contact guide rolls before printing was changed to 30.

[Example 3]
A gas barrier film was produced in the same manner as in Example 2 except that the base material 1 was changed to the base material 2.

[Comparative Example 1]
A gas barrier film was produced in the same manner as in Example 1 except that the number of contact guide rolls before printing was changed to 10.

The above evaluation results are shown in Table 1.

From the evaluation results described in Table 1, the gas barrier films of Examples 1-3, 30 ° C., the value of the oxygen permeability at a relative humidity of 60% 8~18cm ³ / and ^(m 2 · day · MPa) , Good gas barrier property was obtained.
On the other hand, in Comparative Example 1, the value of the oxygen permeability ^{52cm 3 / (m 2 · day} · MPa) , and the good gas barrier property was not obtained.

In addition, the evaluation results of blocking resistance were good in all cases.
Further, regarding the evaluation of the number of irregularities on the film surface, it was confirmed that in all of Examples 1 to 3 as opposed to Comparative Example 1, many recesses presumed to be due to the desorption of the antiblocking agent were formed. As a result, it was confirmed that Examples 1 to 3 had better oxygen barrier properties as compared with Comparative Example 1.

1 ... Base film 2a ... Unwinding roll 2b ... Printing roll 2c ... Winding roll 3 ... Guide roll 4 ... Coating agent 5 ... Oven 10 ... Conveying device 11 ... Base film 12 ... Gas barrier layer 20 ... Printing device 30 ... Gas barrier film

Claims (6)

A transport device that transports a base film containing an anti-blocking agent.
An unwinding part having an unwinding roll for unwinding the base film,
A winding section having a winding roll for winding the base film, and
It is provided with 20 or more guide rolls arranged between the unwinding portion and the winding portion.
The base film is a transport device for transporting between the unwinding portion and the winding portion at a speed of 200 m / min or more. The transport device according to claim 1, further comprising a printing unit for forming a gas barrier layer on the base film and a mechanism for heating and drying the base film. The transport device according to claim 2, wherein the printing unit has a wet coating mechanism. It is a manufacturing method of gas barrier film.
A process of bringing a base film made of a plastic material containing an anti-blocking agent into contact with 20 or more guide rolls at a transport speed of 200 m / min or more.
A step of forming a gas barrier layer on at least one surface of the base material, and
A method for producing a gas barrier film. The method for producing a gas barrier film according to claim 4, wherein the antiblocking agent is any one of silica, talc, diatomaceous earth, and an acrylic polymer. The method for producing a gas barrier film according to claim 4 or 5, wherein the gas barrier layer contains a water-soluble polymer and an inorganic layered mineral as main components.

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