JPH07266441A - Manufacture of gas barrier film - Google Patents

Abstract

PURPOSE:To economically manufacture the film, which has favorable transparency, few wrinkle and oxygen gas barrier properties by a method wherein the film is manufactured by heat-treating laminated thermoplastic film having the layer made of the specified component applied on one side of the film through the contact with a heated roll. CONSTITUTION:On one side of the thermoplastic film having the crystalline melting point of 200-380 deg.C and the Vicat softening temperature of 200-380 deg.C, mixture made of organic compound, which is selected from the group consisting of polyvinyl alcohol and starch flour and contains at least one kind of hydroxyl group, poly(meth)acrylic acid and solvent is applied so as to obtain laminated film containing the resultant coated layer and the thermoplastic film layer after being heat-treated through the contact with the surface of a roll heated up to 180 deg.C or higher. The heat treatment is performed by bringing at first the surface of the heated roll into contact with the thermoplastic film layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention produces a film by applying a heat treatment to a laminated film in which a layer made of specific components is applied to one surface of a thermoplastic film and heat-treating the film. More particularly, it relates to a method for economically producing a film having good transparency, few wrinkles, and an excellent oxygen gas barrier property.

[0002]

2. Description of the Related Art It is one of the important requirements for a packaging film, especially a food packaging film, to prevent deterioration of the quality of a packaged article, and various improvement measures have been studied so far in order to meet this requirement. Is coming. The method of improving the oxygen gas barrier property of the packaging film is one of the effective methods of improvement, and as a typical example, vinylidene chloride copolymer [abbreviated as PVDC] film or ethylene / vinyl alcohol copolymer A method of using a combined [abbreviated as EVOH] film as a single layer or a multi-layered film with another thermoplastic film, a method of using a polyvinyl alcohol [abbreviated as PVA] film coated with PVDC latex, and the like are widely known. However, EVO
The H film and the PVA film have a large humidity dependency of the oxygen gas barrier property, and the prevention of deterioration of the oxygen gas barrier property due to moisture absorption is not yet sufficient. On the other hand, PVD
C film is preferable because it has a good oxygen gas barrier property and its humidity dependency is small, but it is feared that it will affect the environment during incineration.

The inventors of the present invention proceeded with research from this point of view, and from PVA or starch and poly (meth) acrylic acid, the oxygen gas barrier property was excellent and the humidity dependency was small. Film was proposed (Japanese Patent Application No. 5-31404, No. 5-262959, No. 5-285739, No. 6-23735, No. 6-2373).
No. 6). Moreover, this film has no fear of giving to the environment at the time of incineration. However, this film has performance problems such as insufficient transparency and many wrinkles, and economical problems such as lack of industrial manufacturability because it is manufactured by heat treatment in an oven. It was found that the present inventors have further studied to solve these problems and finally arrived at the present invention.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in terms of performance and economy of the film, which is excellent in transparency, has less wrinkles, and is an excellent oxygen gas barrier. The object of the present invention is to provide a method for economically producing a film having good properties with industrial productivity.

[0005]

That is, the gist of the present invention is to provide one side of a thermoplastic film having a crystal melting point of 200 to 380 ° C or a Vicat softening temperature of 200 to 380 ° C.
A coating layer obtained by coating a mixture of an organic compound having at least one hydroxyl group selected from PVA and starch, poly (meth) acrylic acid and a solvent, and removing the solvent, and a thermoplastic film layer Production of a gas barrier film in which a laminated film is heat-treated by contacting it with a heat roll surface of 180 ° C. or higher, and the heat roll surface is first contacted with the thermoplastic film layer of the laminate film and heat treatment is performed. On the way.

The present invention will be described in detail below. [Thermoplastic Film] The thermoplastic film used in the present invention has a crystal melting point of 200 to 380 ° C., preferably 210.
To 380 ° C, more preferably 220 to 380 ° C, or have a Vicat softening temperature of 200 to 380 ° C, preferably 210 to 380 ° C, more preferably 220 to 3 ° C.
It is a thermoplastic film in the range of 80 ° C. The present invention is not limited as long as it uses a thermoplastic film having such a temperature range,
Preferred is poly (ethylene terephthalate)
[Abbreviated as PET], poly (ε-caprolactam) [abbreviated as nylon 6], poly (hexamethylene adipamide)
[Nylon 66], poly (hexamethylene sebacamide) [nylon 610], poly (hexamethylene dodecamide) [nylon 612], ε-caprolactam / hexamethylene adipamide / hexamethylene sebaca Copolymerized polyamide containing a component selected from amide / hexamethylene dodecamide as a copolymerization component, poly (meta-xylylene adipamide), poly (4-methylpentene-1) [abbreviated as PMP], poly (phenylene sulfide) The film obtained from the above can be exemplified. These may be unstretched or stretched. If the crystal melting point is less than 200 ° C or the Vicat softening temperature is less than 200 ° C, the thermoplastic film may undergo deformation such as waviness, stick to a heat roll, or be thermally deteriorated during heat treatment. .
On the other hand, if the crystal melting point exceeds 380 ° C. or the Vicat softening temperature exceeds 380 ° C., the adhesion of the thermoplastic film to the heat roll becomes poor, and uniform heat treatment becomes difficult.

The crystal melting point of the thermoplastic film was measured at 25 ° C. using a differential scanning calorimeter [abbreviated as DSC].
To Tx ° C. at a temperature of 10 ° C./minute, then rapidly cooled to 25 ° C., and again the temperature of Tx ° C. at a temperature of 10 ° C./minute is used. Where T
x ° C. means the temperature obtained by adding 30 ° C. to the crystal melting peak temperature Tp ° C. when the temperature is raised from 25 ° C. to 400 ° C. at 10 ° C./min. In addition, the Vicat softening temperature is ASTM D
It is measured based on -1525.

[Organic Compound Having Hydroxyl Group] The organic compound having a hydroxyl group used in the present invention is at least one compound selected from PVA and starch. PV
A has a saponification degree of 95% or more, preferably 98% or more, and an average degree of polymerization of 300 to 2500, preferably 300.
-1500 is preferable. When the saponification degree is less than 95%, the oxygen gas barrier property of the obtained film is not sufficient. Further, if the average degree of polymerization is less than 300, mechanical strength may be a problem, while if it exceeds 1500, mixing with a solvent becomes difficult.

Examples of the starch used in the present invention include raw starch (unmodified starch) such as wheat starch, corn starch, waxy corn starch, potato starch, tapioca starch, rice starch, sweet potato starch and sago starch, as well as various starches. There is processed starch. Examples of the processed starch include pregelatinized starch,
Separation and Purification Physically modified starch such as amylose, enzymatically modified starch such as hydrolyzed dextrin, enzymatically decomposed dextrin, chemically treated modified starch such as acid-treated starch, hypochlorous acid oxidized starch, esterified starch, etherified starch, etc. Examples thereof include modified starch and grafted starch obtained by grafting a monomer on various starches.

[Poly (meth) acrylic acid] The poly (meth) acrylic acid used in the present invention is a compound containing two or more carboxyl groups. The average molecular weight is not particularly limited, but it is preferably in the range of 2000 to 250,000. Specific examples thereof include polyacrylic acid, polymethacrylic acid, copolymers of acrylic acid and methacrylic acid, and partially neutralized products thereof. The partially neutralized product can be obtained by partially neutralizing the carboxyl groups of these polymers with an alkali. Examples of the alkali include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide, ammonium hydroxide and the like. The degree of neutralization of the partially neutralized product is 20% or less, preferably 15% or less, and more preferably 5 to 15% from the viewpoint of the oxygen gas barrier property of the obtained film. The degree of neutralization can be calculated by the following formula. Degree of neutralization = (X / Y) × 100 X: Total number of moles of neutralized carboxyl groups in 1 g of partially neutralized poly (meth) acrylic acid Y: Poly (meth) acrylic before partial neutralization Total moles of carboxyl groups in 1 g of acid

Preparation of Mixture A mixture of at least one hydroxyl group-containing organic compound selected from PVA and starch, poly (meth) acrylic acid and a solvent is a hydroxyl group-containing organic compound and poly (meth) A method of dissolving acrylic acid in a solvent, a method of mixing a solution of a hydroxyl group-containing organic compound in a solvent and a solution of poly (meth) acrylic acid in a solvent, and a hydroxyl group-containing organic compound in a solvent. It can be appropriately adjusted by, for example, a method of polymerizing a (meth) acrylic acid monomer in a dissolved solution. The solvent can be used as long as it dissolves a hydroxyl group-containing organic compound or poly (meth) acrylic acid, and preferred examples include water, alcohol, or a mixed solvent of water and alcohol. You can Of these, water is preferable in terms of handleability.

The mixing ratio of the hydroxyl group-containing organic compound and the poly (meth) acrylic acid is 5 to 80% by mass of the hydroxyl group-containing organic compound and 9% of the poly (meth) acrylic acid.
5 to 20% by mass, preferably 9 to 10 to 60% by mass
It is in the range of 0 to 40 mass%, more preferably 15 to 50 mass%, and 85 to 50 mass%. When the mixing ratio of the organic compound having a hydroxyl group is less than 5% by mass or more than 80% by mass, a film having an excellent oxygen gas barrier property cannot be obtained. The amount of the solvent in the mixture is 100 to 10,000 parts by mass, preferably 150 to 5,000 parts by mass, and more preferably 100 to 10,000 parts by mass of the composition composed of the organic compound having a hydroxyl group and poly (meth) acrylic acid. A range of 200 to 2500 parts by mass is suitable. If the amount of solvent is less than 100 parts by mass, uniform mixing becomes difficult,
On the other hand, if the amount exceeds 10,000 parts by mass, it becomes difficult to form a uniform film after removing the solvent. The mass used in the present invention can be replaced with the weight. Further, the mixture may be mixed with conventionally known additives such as a heat stabilizer, an ultraviolet absorber, a plasticizer, a lubricant and a pigment.

[Production of Laminated Film] The laminated film of the present invention is obtained by applying the above mixture to one surface of a thermoplastic film and removing the solvent, and contains a coating layer and a thermoplastic film layer. To do. The application of the mixture to one surface of the thermoplastic film is not particularly limited, and can be performed by, for example, a method of casting the mixture on one surface of the thermoplastic film. This can be suitably carried out using a conventionally known device, for example, a kiss roll coater, a metering bar coater, a reverse roll coater or the like. Then, hot air blowing, infrared irradiation,
The solvent is removed from the mixture coated on the surface of the thermoplastic film by a known drying method such as reduced pressure to obtain a laminated film containing the coating layer and the thermoplastic film layer. The thickness of the coating layer and the thermoplastic film layer can be appropriately determined depending on the purpose of use and is not limited, but the coating layer is 0.1 to 500 μm, preferably 0.5 to 10 μm.
0 μm, more preferably about 0.5 to 50 μm, and the thermoplastic film layer has a thickness of 1 to 2000 μm, preferably 3 to 1000 μm, further preferably 5 to 500 μm.

[Heat Treatment] The heat treatment of the present invention is carried out by bringing the above-mentioned laminated film into contact with the surface of the heat roll, and at the beginning of the heat treatment, the surface of the heat roll is brought into contact with the thermoplastic film layer of the laminate film. It is a thing. The temperature and time for performing the heat treatment may be determined from the viewpoints of the economical efficiency for producing the film and the degree of the oxygen gas barrier property of the intended film, and the laminated film may be formed on the surface of a heat roll of 180 ° C. or higher. It can be appropriately selected within the conditions of contacting for 1800 seconds. Specifically, for 4 to 600 seconds, preferably 4 to 3 seconds on the surface of the heat roll at 190 ° C or higher and below the decomposition temperature of the thermoplastic film, preferably 200 ° C or above and below the decomposition temperature of the thermoplastic film.
It is suitable to carry out contact for 00 seconds, more preferably for 4 to 120 seconds. If the temperature of the hot roll is less than 180 ° C., it takes a long time to obtain a film having a low humidity dependency and an excellent oxygen gas barrier property, which is a problem in economical production. On the other hand, when the decomposition temperature is exceeded, the obtained film is difficult to be colored and decomposed products are generated. Further, if the heat treatment time is less than 4 seconds, the oxygen gas barrier property is not sufficient, and conversely, 180
If it exceeds 0 seconds, it takes a long time and there is a difficulty in economically manufacturing. In the present invention, the contact time between the laminated film and the surface of the heat roll represents the total contact time between the laminated film and the surface of each heat roll when a plurality of heat rolls are used. The decomposition temperature is
It is measured by a thermobalance method. When the thermoplastic film is heated from 25 ° C at a rate of 10 ° C / min in a nitrogen gas atmosphere, the mass of the thermoplastic film at 25 ° C is 1
It means the temperature when it is reduced by 0% by mass.

In the present invention, the heat treatment of the laminated film is always carried out at the beginning by bringing the surface of the heat roll into contact with the thermoplastic film layer of the laminated film. After this first contact heat treatment of the heat roll surface and the thermoplastic film layer, no matter what order the heat roll surface and the laminated film are contacted, there is no limitation and the coating layer of the laminated film and Alternatively, the heat treatment can be carried out by appropriately combining the contact between the thermoplastic film layer and the surface of the hot roll. As a preferable heat treatment, first, the thermoplastic film layer of the laminated film is brought into contact with the surface of the heat roll, and then the coating layer of the laminated film is brought into contact with the surface of the heat roll. First, the thermoplastic film of the laminated film is brought into contact with the surface of the heat roll. An example is one in which the layers are brought into contact with each other, and then both the thermoplastic film layer of the laminated film and the coating layer are brought into contact with the surface of the hot roll. In addition, first, a heat treatment carried out by bringing the surface of the heat roll into contact with the thermoplastic film layer of the laminated film, that is, a heat treatment in which all of the heat treatment is performed by bringing the surface of the heat roll into contact with the thermoplastic film layer of the laminated film is also preferable. It is a thing.

The heat treatment time by the first contact between the surface of the heat roll and the thermoplastic film layer of the laminated film in the heat treatment time is as follows when the heat treatment is performed by contacting only the surface of the heat roll and the thermoplastic film layer of the laminated film. Although it is not necessary to specify, in the case of other things, it is usually 30% or more and less than 100% of the heat treatment time, preferably 40%.
Time of 100% or more and less than 100%, particularly preferably 50% or more 1
The time range is less than 00%. When the heat treatment time by the first contact in the heat treatment time is less than 30%,
When the surface of the heat roll and the coating layer of the laminated film come into contact,
The laminated film may adhere to the surface of the hot roll. In addition, the heat treatment time by the first contact occupying in the heat treatment time means from the first contact of the thermoplastic film layer of the laminated film with the surface of the heat roll to the time before the first contact of the coating layer of the laminated film with the surface of the heat roll. , The total contact time of contact between the surface of the heat roll and the thermoplastic film layer of the laminated film.

The heat roll for heat-treating the laminated film is not particularly limited as long as it can be adjusted to the above temperature range, and a conventionally known one can be used. Usually, a heatable metal roll is used, and a hard chrome-plated mirror surface finish or a ceramic roll having a metal roll surface coated with ceramic is suitable. The number of heat rolls is not limited at all and may be appropriately selected according to the heat treatment. In addition, if necessary, a conventionally used roll, for example, a roll for pressing, a roll for molding, a roll for cooling, a roll for taking over, etc., are appropriately combined with the hot roll of the present invention. Can be used.

[Gas Barrier Film] The laminated film of the present invention becomes a film excellent in oxygen gas barrier property by heat treatment. This excellent oxygen gas barrier property is exhibited by heat treatment of the coating layer of the laminated film, and the degree of the oxygen gas barrier property is 30.
The oxygen permeability of the coating layer at a thickness of 3 μm after heat treatment is 100 ml under conditions of 80 ° C. and 80% relative humidity (80% RH).
(STP) / m ² · day · atm {Pa} or less, preferably 50 ml (STP) / m ² · day · atm {P
a} or less, more preferably 10 ml (STP) / m ²
-The preferred value is less than day-atm {Pa}. This oxygen permeability is converted into an oxygen permeability coefficient,
1.25 × 10 ^-3 ml (STP) ・ cm / m ²・ h ・ a
tm {Pa} or less, preferably 6.25 × 10 ^-4 ml
(STP) · cm / m ² · h · atm {Pa} or less, more preferably 1.25 × 10 ⁻⁴ ml (STP) · cm
/ M ² · h · atm {Pa} or less. The film obtained by the heat treatment of the present invention has excellent transparency, and is usually a film obtained from a laminated film having a coating layer thickness of about 1 to 5 μm and a thermoplastic film layer thickness of about 10 to 50 μm. In that case, haze of 20% or less, preferably 15% or less, and more preferably 10% or less is exhibited.

The gas barrier film of the present invention may further contain, if necessary, with or without an adhesive layer,
Other layers can be laminated by a lamination method or the like. For example, when a seal layer is arranged separately from the thermoplastic film layer. Examples of preferred laminated structures include coating layer / thermoplastic film layer / adhesive layer / seal layer, sealing layer / adhesive layer / coating layer / thermoplastic film layer, coating layer / thermoplastic film layer / adhesive layer / Coating layer / thermoplastic film layer, sealing layer / coating layer / thermoplastic film layer / adhesive layer /
Coating layer / thermoplastic film layer, etc., but not limited thereto.

As the seal layer, for example, low density polyethylene, linear low density polyethylene, ethylene
Propylene copolymer, ethylene / vinyl acetate copolymer,
Formed from polyolefins such as polypropylene, ethylene / ethyl acrylate copolymer, ethylene / acrylic acid salt copolymer, and copolyamides containing ε-caprolactam, hexamethylene adipamide, hexamethylene dodecamide, etc. Can be mentioned. Examples of the adhesive include urethane-based, acrylic-based, polyester-based adhesives used for lamination of various films.

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. [Examples 1 to 4 and Comparative Examples 1 to 3] As PVA, Poval 105 (saponification degree 98.5%, average degree of polymerization 500) manufactured by Kuraray Co., Ltd. was used, and polyacrylic acid [abbreviated as PAA] was added. PAA manufactured by Kojunkaku Co., Ltd. (8 at 30 ° C
000 to 12,000 centipoise, average molecular weight 1500
00) was used as a 25% by weight aqueous solution. Further, the partially neutralized product of PAA was prepared [abbreviated as PAANA] by partially neutralizing PAA with sodium hydroxide [abbreviated as NaOH] to a degree of neutralization of 10% (DN = 10%). First, PV
An aqueous solution (concentration: 10% by mass) of a mixture of A: PAANa = 30: 70 (mass ratio) was prepared, and this aqueous solution was stretched P using a reverse roll coater and a Mayer bar.
The ET film (melting point 264 ° C.) was coated on one side, and then the film coated with the aqueous solution of the mixture was applied to
The film was introduced into a drying chamber controlled at 0 ° C., and water was removed to obtain a laminated film having a stretched PET layer (thickness 25 μm) and a coating layer (thickness 3 μm). The laminated film thus obtained was heated to the temperature shown in Table 1 (the surface of the metal roll was coated with ceramic, and the surface roughness was 0.6 s or less). Heat treatment was performed so that the stretched PET layers were in contact with each other, and films having the above thickness were obtained (Examples 1 to 4 and Comparative Example 1). The heat treatment time indicates the total contact time during which the stretched PET layer of the laminated film contacts the surface of the ceramic roll. The physical properties of the obtained film are shown in Table 1.

On one side, an unstretched polypropylene [abbreviated as PP] film (melting point 165 ° C.) coated with an anchoring agent (polyester-based polyol and isocyanate-based curing agent) was applied to the coated surface of Examples 1 to 1. An aqueous solution of the mixture was applied in the same manner as in 4, and the unstretched PP layer (thickness 5
0 μm) and a coating layer (thickness 1 μm) were obtained. Then, it was tried to perform heat treatment so that the unstretched PP layer of the laminated film was brought into contact with the surface of the ceramic roll heated to 235 ° C. However, the laminated film adhered to the surface of the ceramic roll and was wound, so that the heat treatment could not be performed. (Comparative example 2). Furthermore, using the laminated film having the stretched PET layer and the coating layer prepared in Examples 1 to 4, the coating layer of the laminated film was brought into contact with the surface of the ceramic roll heated to 235 ° C. to perform heat treatment. However, the laminated film adhered to the surface of the ceramic roll and was wrapped around, and heat treatment could not be performed (Comparative Example 3).

<Physical Properties Measuring Method> (1) Oxygen Permeability Oxygen Permeation Tester O manufactured by Modern Control Co.
Using X-TRAN 2/20, the oxygen permeability of the thermoplastic film alone and the film obtained by heat-treating the laminated film containing the thermoplastic film layer and the coating layer was measured, and the coating layer after the heat treatment was calculated by the following formula. Oxygen permeability P <f
ilm> was calculated. The oxygen permeability of Tables 1 to 4 indicates the oxygen permeability of the coating layer after this heat treatment. 1 / P <total> = 1 / P <film> + 1 / P <thermo> P <total>: Oxygen permeability of a film obtained by heat treatment of a laminated film containing a thermoplastic film layer and a coating layer P <film>: heat treatment Oxygen permeability of subsequent coating layer P <thermo>: Oxygen permeability of thermoplastic film alone (2) Transparency According to ASTM D1003, manufactured by Nippon Denshoku Industries Co., Ltd. Σ
80 was used to measure the haze of the film obtained by heat-treating the laminated film. (3) Wrinkles From the film obtained by heat-treating the laminated film, 50
A cm × 50 cm sample film was cut out, and this sample film was placed on black paper, and the degree of wrinkles was visually observed and measured. A ... almost no wrinkles B ... many wrinkles C ... many wrinkles

[0024]

[Table 1] ─────────────────────────────────── Composition of film Heat treatment Oxygen permeability Transparency Wrinkle Plasticity Coating layer Temperature Time (haze) Film layer (℃) (sec) (ml / m ² · day ・ atm) (%) ───────────────────── ────────────── Example 1 PET PVA + PAANa 215 120 1 3 A Example 2 PET PVA + PAANa 235 57 0.2 4 A Example 3 PET PVA + PAANa 235 14 0.5 4 A Example 4 PET PVA + PAANa 235 6 43 4 A Comparative Example 1 PET PVA + PAANa 160 2100 10 10 A Comparative Example 2 PP PVA + PAANa 235 (* 1) (* 2) (* 2) (* 2) Comparative Example 3 PET PVA + PAANa 235 (* 1) (* 2) (* 2) (* 2) ───────────────────────────── ─────── (* 1) The laminated film adhered to the roll surface and was wrapped. (* 2) The physical properties could not be measured because the film could not be manufactured.

From this table, it can be seen that the method of the present invention makes it possible to economically produce a film having good transparency, few wrinkles, and excellent oxygen gas barrier property (Example 1).
~ 4). On the other hand, in Comparative Example 1, the heat treatment takes time,
The target film cannot be manufactured economically,
Further, in Comparative Examples 2 and 3, it can be seen that the laminated film adheres to the ceramic roll and the film cannot be manufactured.

[Examples 5 to 9 and Comparative Example 4] As the starch, soluble starch manufactured by Wako Pure Chemical Industries, Ltd. (potato starch hydrolyzed by acid to be water-soluble) was used.
A 0 mass% aqueous solution was prepared. PAANA is from Example 1
Starch: PAANa = 30: 7
An aqueous solution (concentration: 10% by mass) of a mixture of 0 (mass ratio) was prepared, and this aqueous solution was applied to one surface of a stretched nylon 6 [abbreviated as NY] film (melting point 220 ° C.), and Examples 1 to 1 Stretched NY layer (thickness 15 μm) in the same manner as 4
A laminated film having a coating layer (thickness 3 μm) was obtained.
The laminated film thus obtained was heated to the temperature shown in Table 2 so that the surface of the ceramic roll was first brought into contact with the stretched NY layer of the laminated film, and then with the coating layer of the laminated film. In this way, a total of two ceramic rolls were passed through to perform heat treatment (Examples 5 to 6). Further, instead of the stretched NY film of Examples 5 to 6, an unstretched PMP film (melting point 235 ° C.) was used, and an unstretched PMP layer (thickness 25 μm) and a coating layer (thickness 3) were used.
μm) and heated to the temperature shown in Table 2 so that the surface of the ceramic roll is first contacted by the unstretched PMP layer of the laminated film and then by the coated layer of the laminated film. Then, a total of two ceramic rolls were passed through for heat treatment (Example 7). Further, the stretched PET film used in Examples 1 to 4 was used in place of the stretched NY film of Examples 5 to 6, and a stretched PET layer (thickness 25 μm) and a coating layer (thickness 3 μm) were used.
m) was obtained and heated to the temperature shown in Table 2 so that the surface of the ceramic roll was first brought into contact with the stretched PET layer of the laminated film and then with the applied layer of the laminated film. Then, a total of two ceramic rolls were passed through for heat treatment (Example 8).
Further, the stretched PET layer prepared in Examples 1 to 4 (thickness 25
μm) and a coating film (thickness: 3 μm), and heated to the temperature shown in Table 2 so that the surface of the ceramic roll is first brought into contact with the stretched PET layer of the lamination film, and then the lamination film. So that the coating layers of are in contact with each other and pass through a total of two ceramic rolls,
Heat treatment was performed (Example 9). In each of the examples, a film having the same thickness as the laminated film was obtained.

Further, as comparative examples, the above-mentioned Examples 5-6 are used.
Using the laminated film having the stretched NY layer and the coating layer prepared in step 1, the surface of the ceramic roll heated to 230 ° C. is first contacted with the coating layer of the lamination film, and then with the stretching NY layer of the lamination film. In this way, an attempt was made to pass through a total of two ceramic rolls, but the heat treatment could not be performed because the laminated film adhered to the roll surface and was wound around the first ceramic roll (Comparative Example 4). The heat treatment time indicates the total contact time during which the stretched NY layer or unstretched PMP layer or stretched PET layer of the laminated film and the coating layer contact the surface of the two ceramic rolls. Half of
The ceramic roll and the stretched NY layer or unstretched PMP layer or stretched PET layer of the laminated film were in contact with each other, and the other half was the contact time of the ceramic roll with the coating layer.

[0028]

[Table 2] ─────────────────────────────────── Film composition Heat treatment Oxygen permeability Transparency Wrinkle Plasticity Coating layer Temperature Time (haze) Film layer (℃) (sec) (ml / m ² · day ・ atm) (%) ───────────────────── Example 5 NY Starch + PAANa 205 38 5 10 A Example 6 NY Starch + PAANa 205 60 2 15 A Example 7 PMP Starch + PAANa 200 120 10 10 A Example 8 PET Starch + PAANa 230 38 0.2 7 A Example 9 PET PVA + PAANa 230 8 34 5 A Comparative Example 4 NY Starch + PAANa 230 (* 3) (* 4) (* 4) (* 4) ── ───────────────────────────────── (* 3) The laminated film adhered to the roll surface and was wrapped. (* 4) The physical properties could not be measured because the film could not be manufactured.

From this table, it can be seen that according to the present invention, a film having good transparency, few wrinkles and an excellent oxygen gas barrier property can be produced economically (Examples 5 to 5).
9). On the other hand, in Comparative Example 4, it can be seen that the laminated film adhered to the ceramic roll and the film could not be manufactured.

[Examples 10 to 11] The stretched PET layer (thickness: 25 µm) prepared in Examples 1 to 4 and the coating layer (thickness: 3 µm)
m) was applied to the surface of the ceramic roll heated to the temperature shown in Table 3 so that the expanded PET layer of the laminated film was in contact first, and then the expanded PET layer of the laminated film was applied. Heat treatment was performed by passing a total of three ceramic rolls so that the roll surfaces were in contact with both layers of the layers (Example 10). Further, using the laminated film having the stretched NY layer (thickness 15 μm) and the coating layer (thickness 3 μm) prepared in Examples 5 to 6, the surface of the ceramic roll heated to the temperature shown in Table 3 was used. In the same manner as in No. 10, heat treatment was performed by first contacting the stretched NY layer of the laminated film and then contacting both the stretched NY layer of the laminated film and the coating layer with the roll surface (implementation). Example 11). In each of the examples, a film having the same thickness as the laminated film was obtained. Table 3 shows the physical properties of the obtained film. In addition,
The heat treatment time indicates the total contact time during which the stretched PET layer or stretched NY layer of the laminated film and the coating layer contacted the surfaces of the three ceramic rolls. The first half of this total contact time was The time when the stretched PET layer or the stretched NY layer of the laminated film was in contact, and the other half was the time when the stretched PET layer or stretched NY layer of the laminated film was in contact with both coating layers (the ceramic roll was Stretched PE for laminated film
The time when the T layer or the stretched NY layer is in contact is the same as the time when the coating layer of the laminated film is in contact with the ceramic roll)
Indicates.

[0031]

[Table 3] ─────────────────────────────────── Composition of film Heat treatment Oxygen permeability Transparency Wrinkle Plasticity Coating layer Temperature Time (haze) Film layer (℃) (sec) (ml / m ² · day ・ atm) (%) ───────────────────── ────────────── Example 10 PET PVA + PAANa 230 8 37 3 A Example 11 NY Starch + PAANa 205 60 2 15 A ───────────── ───────────────────────

[Comparative Examples 5 to 6] The stretched PET layer (thickness: 25 μm) and the coating layer (thickness: 3 μm) obtained in Examples 1 to 4
The laminated film having No. 2 was fixed on a cardboard and placed in a heating chamber at 160 ° C. for 2 hours to perform heat treatment (Comparative Example 5). The laminated film having the unstretched PP layer (thickness 50 μm) and the coating layer (thickness 1 μm) obtained in Comparative Example 2 was fixed on a cardboard and placed in a heating chamber at 130 ° C. for 110 hours for heat treatment. (Comparative example 6). Table 4 shows the physical properties of the obtained film.

[0032]

[Table 4] ─────────────────────────────────── Composition of film Heat treatment Oxygen permeability Transparency Wrinkle Plasticity Coating layer Temperature Time (haze) Film layer (℃) (hours) (ml / m ² · day ・ atm) (%) ───────────────────── ────────────── Comparative Example 5 PET PVA + PAANa 160 2 1 26 C Comparative Example 6 PP PVA + PAANa 130 110 3 25 C ───────────── ───────────────────────

From this table, it can be seen that the intended film cannot be obtained unless the laminated film and the surface of the heat roll are heat-treated.

[0034]

According to the present invention, there is provided a method for economically producing a film having good transparency, few wrinkles, and an excellent oxygen gas barrier property. This makes it possible to manufacture a film suitable for food packaging and having no concern about the environment at the time of incineration, with good handleability (obtained in a rolled shape) and on a production scale.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C08J 7/00 301 7/04 P // B29K 29:00 33:00 101: 12

Claims (7)

[Claims] 1. A thermoplastic film having a crystal melting point of 200 to 380 ° C. or a Vicat softening temperature of 200 to 380 ° C., on one surface thereof, an organic compound containing at least one hydroxyl group selected from polyvinyl alcohol and starch, poly ( A method for applying a mixture of (meth) acrylic acid and a solvent, removing the solvent, and subjecting a laminated film containing a coating film and a thermoplastic film layer to a heat roll surface of 180 ° C. or more to heat-treat A method for producing a gas barrier film in which the heat roll surface and the thermoplastic film layer of the laminated film are brought into contact with each other at the beginning of the heat treatment to perform the heat treatment. 2. The gas barrier according to claim 1, wherein the heat treatment is carried out by first contacting the surface of the heat roll with the thermoplastic film layer of the laminated film and then contacting the surface of the heat roll with the coating layer of the laminated film. Of producing a transparent film. 3. The heat treatment is carried out by first contacting the surface of the heat roll with the thermoplastic film layer of the laminated film, and then contacting both the thermoplastic film layer of the laminate film and the coating layer with the surface of the heat roll. A method for producing a gas barrier film according to claim 1. 4. The laminated film is heat-treated at a temperature of 190 ° C. or higher and a thermoplastic film decomposition temperature or lower to 4 to 4 times the laminated film.
The method for producing a gas barrier film according to claim 1, which is carried out for 600 seconds. 5. A mixture of 5 to 80% by mass of an organic compound containing at least one hydroxyl group selected from polyvinyl alcohol and starch, and poly (meth) acrylic acid 9
100 parts by mass of a composition consisting of 5 to 20% by mass, and 10 parts of water
The method for producing a gas barrier film according to claim 1, which comprises 0 to 10000 parts by mass. 6. A thermoplastic film having a crystal melting point of 200 to 380 ° C. or a Vicat softening temperature of 200 to 380 ° C.
Poly (ethylene terephthalate), poly (ε-caprolactam), poly (hexamethylene adipamide), poly (hexamethylene sebacamide), poly (hexamethylene dodecamide), the copolyamide, poly (metaxylylene azide) The method for producing a gas barrier film according to claim 1, which is selected from a film obtained from pamide), poly (4-methylpentene-1) and poly (phenylene sulfide). 7. A partially neutralized product of polyacrylic acid, polymethacrylic acid, polyacrylic acid (neutralization degree of 20% or less) and partially neutralized product of polymethacrylic acid (neutralization degree). 20% or less), The method for producing a gas barrier film according to any one of claims 1 to 6.