JP2000080188A - Production of laminated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminated film desirable as a gas barrier film having high adhesiveness by subjecting at least either surface of a film based on a thermoplastic resin to a surface treatment comprising corona discharge in nitrogen and/or carbon dioxide gas atmosphere and a flame plasma treatment and laminating a layer of a resin based on a water-soluble polymer on the treated surface. SOLUTION: The starting resin for the base film is an olefin resin, especially, polypropylene. It is the most desirable that during the corona discharge treatment, the oxygen concentration in nitrogen and/or carbon dioxide gas is at most 3 vol.%, and the corona discharge treatment density is 10-100 W.min/m2. The flame plasma treatment consists of blowing an ionized plasma in a flame of e.g. LPG onto the surface of the base film. Thus, a base film not undergoing blocking, etc., can be obtained. It is desirable that the water-soluble polymer is a polyvinyl alcohol polymer, and the thickness of the resin layer is 0.3-6 μm on account of gas barrier properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pouch film suitable as a packaging film. Specifically, it is a method for producing a laminated film having good gas barrier properties.

[0002]

2. Description of the Related Art Thermoplastic resin films, such as polypropylene films and PET films, have good workability for being thermoplastic and have excellent mechanical strength.
It is widely used as a packaging film because of its secondary workability such as transparency and bag making.

On the other hand, water-soluble polymers such as polyvinyl alcohol (hereinafter referred to as PVA) are laminated on the surface of these thermoplastic resin films for the purpose of imparting functions such as gas barrier properties. In particular, a film having a low surface polarity, such as a polypropylene film, has a problem in that the productivity is lowered and the product is inferior due to insufficient adhesion. Further, in order to improve such adhesiveness, an adhesive layer made of an anchor coat agent or the like is generally provided, although the cost is increased.

[0004] As means for solving the above problems, the surface of the polyolefin film is subjected to a surface treatment comprising both a flame treatment (flame plasma treatment) and a corona treatment (JP-A-55-133959, JP-A-55-146).
747). However, JP-A-55-1
The method disclosed in 33959 is that, after laminating an ionomer-based polyolefin copolymer on the surface-treated surface of the surface-treated polypropylene film, further laminating a layer having a gas barrier function such as polyvinylidene chloride latex, An adhesive layer is required, and there is still room for improvement in the adhesiveness to a water-soluble polymer when the adhesive layer is removed. In addition, there is no description in this document regarding the atmospheric conditions of corona treatment.

On the other hand, the method disclosed in JP-A-55-146747 is a method for producing a composite film in which a vinylpyrrolidone polymer is laminated on the surface-treated surface of a polyolefin film subjected to the above-mentioned surface treatment. Is only a corona treatment, and the corona treatment is carried out in the atmosphere. As described above, there is still room for improvement in the adhesiveness with the water-soluble polymer of the film that has been subjected to the corona treatment in the atmosphere and the flame plasma treatment at the time of the treatment.

[0006] Japanese Patent Application Laid-Open No. 9-1111017 discloses that
The surface of the thermoplastic resin substrate film is subjected to a corona discharge treatment substantially under a nitrogen gas atmosphere or a nitrogen / carbon dioxide gas atmosphere, and the surface-treated surface is mainly composed of a water-soluble polymer and an inorganic layered compound. A method for forming a coated film is disclosed. However, although the above-mentioned invention has a certain improvement effect with respect to the gas barrier property, there is still room for improvement with respect to the adhesive property when an adhesive layer such as an anchor coat layer is not used.

On the other hand, as a method of laminating a resin layer containing a water-soluble polymer as a main component on a laminated film, generally an off-line coating is frequently used. It is also required to have good characteristics such as low handling properties.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thermoplastic resin base film in which a resin layer containing a water-soluble polymer as a main component can be used to form a strong adhesive layer without using an adhesive layer such as an anchor coat. It is an object of the present invention to provide a method for producing a laminated film, which is low in blocking and the like in a thermoplastic resin base film having been subjected to surface treatment in a production process of the laminated body and has good productivity.

[0009]

Means for Solving the Problems In order to achieve the above object, the present inventors have attempted to obtain strong adhesion between a thermoplastic resin base film and a resin layer containing a water-soluble polymer as a main component. , And have been conducting diligent research.

As a result, a surface treatment combining a corona discharge treatment and a flame plasma treatment in a specific atmosphere is applied to the thermoplastic resin film, and a resin layer mainly containing a water-soluble polymer is laminated on the surface to be treated. As a result, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, in the present invention, at least one surface of a thermoplastic resin base film is subjected to a corona discharge treatment and a flame plasma treatment in a nitrogen and / or carbon dioxide gas atmosphere, and the surface to be treated is treated with a water-soluble polymer. A method for producing a laminated film, comprising laminating a resin layer containing as a main component.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides both a surface treatment comprising both a corona discharge treatment under a nitrogen and / or carbon dioxide gas atmosphere and a flame plasma treatment on at least one surface of a thermoplastic resin base film. By applying, even without providing an adhesive layer such as a special anchor coating agent, even if a resin layer containing a water-soluble polymer as a main component is directly laminated on the surface-treated surface, the resin layer firmly adheres, and is suitable. A laminated film having excellent gas barrier properties can be obtained, and its effectiveness is extremely high.

[0013] The thermoplastic resin base film (hereinafter also referred to as base film) used in the present invention is necessary mainly for imparting mechanical properties, secondary workability of the film, and the like. Various commercially available thermoplastic resin films are included. Examples of the thermoplastic resin as a raw material resin for such a base film include olefin resins such as polyethylene and polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,
Polyester resins such as 6-naphthalate, polyamide resins such as nylon 6 and nylon 12, polyvinyl chloride, ethylene-vinyl acetate copolymer or saponified product thereof,
Polystyrene, polycarbonate, polysulfone, polyphenylene oxide, polyphenylene sulfide,
Examples thereof include aromatic polyamide, polyimide, polyamideimide, cellulose, cellulose acetate, polyvinylidene chloride, polyacrylonitrile, polyvinyl alcohol, and the like, and copolymers thereof. Among these, transparency,
Taking into account secondary workability and the like, polyolefin resins such as polyethylene and polypropylene or polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene-2,6-naphthalate are preferred. Is more preferable, and polypropylene is particularly preferable.

The present invention exhibits a particularly remarkable effect when an olefin resin, particularly, polypropylene is used as a raw material resin for the base film.

Examples of the polypropylene used as the base film material include propylene homopolymer, α other than propylene and propylene, such as ethylene, 1-butene, 1-pentene, 1-hexene and 4-methyl-1-pentene. -Random or block copolymers with olefins,
Further, a mixture of these polymers may be mentioned, and among them,
Preferred are a propylene homopolymer, a propylene-ethylene random copolymer, and a propylene-ethylene-butene terpolymer.

Further, the method for producing the above polypropylene is as follows:
Known methods can be used without any limitation, for example, TiCl ₃
A method of polymerizing the above-mentioned monomer using a known polymerization catalyst for polypropylene, such as supported TiCl _{3 or} a metallocene catalyst, may be mentioned. Further, after polymerization using the above catalyst, a method of decomposing with a peroxide or the like may be performed.

The melting point of the above-mentioned polypropylene is such that the peak-top measured value in the differential scanning calorimetry (hereinafter referred to as DSC) is 130 to 16 in consideration of the heat resistance of the film.
The temperature is preferably 5 ° C, more preferably 135 to 165 ° C. In addition, the melt flow rate (hereinafter referred to as M
FR) is 0.1 to 10 in consideration of extrudability.
g / 10 minutes, preferably 0.5 to 5 g / 10 minutes.
More preferably, it is minutes.

Further, other resins can be mixed with the polypropylene to such an extent that the effects of the present invention are not impaired. The resin to be mixed is not particularly limited, but is generally one or more homopolymers and copolymers of polyolefin resins such as polypropylene, polyethylene, and polybutene, a polyolefin wax, a polyolefin elastomer, or Examples thereof include hydrocarbon resins such as petroleum resins and terpene resins, copolymers of ethylene with vinyl acetate, acrylates, and acrylate monomers, or mixtures of two or more of these polymers.

When polypropylene is used for the thermoplastic resin base film of the present invention, the base film may be a single-layer film or a laminated film. Specifically, a single-layer film mainly composed of propylene homopolymer, a layer mainly composed of propylene homopolymer, and a random copolymer of propylene and an α-olefin other than propylene are mainly composed. A laminated film with a layer is exemplified.

The thermoplastic resin base film of the present invention may be any of unstretched, uniaxially stretched and biaxially stretched. However, in consideration of mechanical properties, secondary workability, etc., it may be a biaxially stretched film. preferable. Although the thickness of the substrate film is not particularly limited, it is generally appropriately selected in the range of 1 to 500 μm.

The thermoplastic resin base film of the present invention comprises:
If necessary, a known addition of an antistatic agent, an antifogging agent, an antiblocking agent, an antioxidant, a light stabilizer, a crystal nucleating agent, a lubricant, a surfactant for the purpose of imparting a slipperiness and an antiblocking property, or the like. You may mix | blend an agent. The thermoplastic resin substrate film of the present invention is preferably transparent in consideration of being suitably used for packaging applications, particularly as a gas barrier film, and has a haze value of preferably 15% or less, more preferably 10% or less. More preferably, there is.

The surface treatment step of the present invention is performed by performing the following specific corona discharge treatment and flame plasma treatment. Although the order of the above treatment is not particularly limited, it is preferable to perform the flame plasma treatment after the specific corona discharge treatment in consideration of the adhesiveness with the water-soluble polymer.

In the present invention, the corona discharge treatment is carried out by applying nitrogen and / or
Alternatively, it is performed by performing a corona discharge treatment in a carbon dioxide gas atmosphere. The corona discharge treatment is performed, for example, by passing the thermoplastic resin base film through the generated corona atmosphere using a known corona discharge treatment machine.
The atmosphere at the time of the corona discharge treatment needs to be a nitrogen and / or carbon dioxide gas atmosphere, and is preferably a nitrogen atmosphere in consideration of economy.

The oxygen concentration in a substantial nitrogen and / or carbon dioxide gas atmosphere is preferably 5% by volume or less in consideration of the adhesion to a resin layer containing a water-soluble polymer as a main component. More preferably, it is not more than% by volume.

Further, the corona discharge treatment density calculated by voltage × current / (electrode width × film running speed) (W · min / m ² ) is preferably 1 to 200 W · min / m ² , more preferably ~150W · min / m ^2, further preferably 10~100W · min / m ^2. Processing density is 1W · min / m
If it is lower than ² , the adhesiveness to the resin layer containing a water-soluble polymer as a main component is lowered, which is not preferable.
When it is higher than min / m ² , blocking between thermoplastic resin base films occurs, which is not preferable.

In the present invention, the wetting index of the surface to be treated after the corona discharge treatment of the thermoplastic resin base film is as follows:
When the corona discharge treatment is performed first, 35 to 55 mN /
m, more preferably 38 to 50 mN / m, even more preferably 40 to 48 mN / m. When the wetting index is less than 35 mN / m, the adhesiveness to the resin layer containing a water-soluble polymer as a main component is unfavorably reduced, and when it is higher than 55 mN / m, blocking between thermoplastic resin base films is performed. And unevenness in processing with different processing degrees in the width direction of the film occurs. The processing unevenness is not preferable because it causes a coating unevenness and an adhesive strength unevenness during coating.

On the other hand, when the corona discharge treatment is performed later, the final wetting index of the surface to be treated after the corona discharge treatment is preferably 40 to 65 mN / m, and preferably 4 to 65 mN / m.
It is more preferably 3 to 60 mN / m, and more preferably 45 to 5 mN / m.
More preferably, it is 8 mN / m. Wetting index is 4
If it is lower than 0 mN / m, the adhesiveness to a resin layer containing a water-soluble polymer as a main component is lowered, which is not preferable.
If it is higher than 5 mN / m, it is not preferable because blocking between thermoplastic resin base films and unevenness in processing occur.

In the present invention, in the flame plasma treatment step, ionized plasma in a flame generated when natural gas, LPG, propane gas, butane gas or the like is burned by a burner or the like is blown onto the surface of the thermoplastic resin base film. It can be implemented by doing.

The flame plasma treatment intensity calculated by the burner output / (burner width × film running speed) (kcal / m ²⁾ is preferably 1~15kcal / m ^2, is 2~10kcal / m ² More preferably, it is 3 to 8 kcal / m ² .

When the treatment strength is lower than 1 kcal / m ² , the adhesion to the resin layer containing a water-soluble polymer as a main component is unfavorably reduced. When the treatment strength is higher than 15 kcal / m ^{2, the} thermoplastic resin is used. The base film is not preferable because it generates wrinkles due to heat shrinkage.

The distance between the burner device and the surface of the thermoplastic resin substrate film as an object to be processed varies depending on the size of the frame, but is usually appropriately selected in the range of 10 to 100 mm. The distance from the end of the inner flame of the frame to the surface of the thermoplastic resin base film as the object to be treated is preferably 1 to 5 mm, and more preferably 1 to 3 mm, in consideration of the stability of the treatment level. More preferred.

Regarding the temperature control of the film at the time of the frame plasma processing, a method is generally employed in which a cooling roll is brought into contact with one side of the film and a frame plasma is sprayed on the opposite side of the film while the film is running. It is. The temperature of the cooling roll is appropriately selected from the range of room temperature to 60 ° C, and is preferably 30 to 45 ° C.

In the present invention, the wetting index of the surface to be treated of the thermoplastic resin base film after the flame plasma treatment is 35 when the flame plasma treatment is performed first.
６０60 mN / m, preferably 38-58 mN
/ M, more preferably 40 to 55 mN / m. When the wetting index is less than 35 mN / m, the adhesiveness to the resin layer containing a water-soluble polymer as a main component is reduced, which is not preferable.
A higher value is not preferred because wrinkles due to thermal shrinkage of the thermoplastic resin base film and blocking between the thermoplastic resin base films occur.

On the other hand, when the flame plasma treatment is performed later, the final wetting index of the surface to be treated after the flame plasma treatment is preferably 40 to 68 mN / m, and more preferably 43 to 65 mN / m. More preferably, it is more preferably 45 to 63 mN / m.
When the wetting index is lower than 40 mN / m, it is not preferable because the adhesion to the resin layer containing a water-soluble polymer as a main component is reduced. When the wetting index is higher than 68 mN / m, blocking between thermoplastic resin base films is performed. Is not preferred because

The surface roughness (Ra value) of the surface to be treated of the thermoplastic resin base film is 0.5 to 1 in consideration of adhesiveness.
The thickness is preferably 00 nm, more preferably 1 to 80 nm, and still more preferably 3 to 50 nm.

In the present invention, a water-soluble polymer is a polymer which can be completely dissolved or finely dispersed in water at ordinary temperature without any particular limitation. Specific examples of the water-soluble polymer include polyvinyl alcohol and derivatives thereof, a polyalcohol obtained by reducing a polyketone composed of a carbon monoxide-ethylene-based copolymer, carboxymethyl cellulose,
Cellulose derivatives such as hydroxyethyl cellulose,
Oxidized starch, etherified starch, starches such as dextrin, polyvinylpyrrolidone, polyacrylic acid,
Examples include vinyl-based copolymers such as polymethacrylic acid, or esters and salts thereof, and copolymers thereof, and functional group-modified polymers of these various polymers with a carboxyl group or the like.

Of these, polyvinyl alcohol polymers and derivatives thereof are preferred.
5 mol% or more of polyvinyl alcohol, 40% of all hydroxyl groups
More preferred are polyvinyl alcohols in which mol% or less is acetalized, and copolymerized polyvinyl alcohols such as ethylene-vinyl alcohol copolymer (hereinafter referred to as EvOH) in which vinyl alcohol units are 60 mol% or more.

[0038] The degree of polymerization of polyvinyl alcohol and its derivatives is 100% in consideration of gas barrier properties and processability.
It is preferably from 5,000 to 5,000, more preferably from 500 to 3,000.

In the resin layer containing a water-soluble polymer as a main component used in the present invention, the mixing ratio of the water-soluble polymer is as follows:
Considering the gas barrier properties and the effects of the present invention, 40 wt%
It is preferably at least 50 wt%, more preferably at least 60 wt%. The component other than the water-soluble polymer is not particularly limited, and examples thereof include inorganic compounds such as inorganic fine particles and inorganic layered compounds. Specifically, kaolin, calcium carbonate, titanium oxide, silicon oxide, alumina, barium sulfate,
Inorganic fine particles such as calcium fluoride, lithium fluoride, zirconia, calcium phosphate, montmorillonite, kaolinite, halloysite, vermiculite, dickite, nacrite, antigolite, virophilite, hectorite, beidellite, margarite, talc, tetrasilyl Examples include inorganic layered compounds such as mica, muscovite, phlogopite and chlorite.

The inorganic compound and the water-soluble polymer may be dispersed and mixed with each other, or may be crosslinked with a crosslinking agent or the like. A siloxane bond is formed two-dimensionally or three-dimensionally by a sol-gel method or the like between molecular chains of the water-soluble polymer and / or on the surface of the water-soluble polymer opposite to the surface contacting the base film. May be used. The crosslinking agent is not particularly limited, but specific examples include a titanium coupling agent, a silane coupling agent, a melamine coupling agent, an epoxy coupling agent, an isocyanate coupling agent, a copper compound, and a zirconia compound. Is mentioned.

Examples of the resin containing a water-soluble polymer as a main component include known resin compositions, for example, JP-A-4-34584.
No. 1, JP-A-6-93133, JP-A-8-99390
No., JP-A-8-245816, JP-A-9-111017
JP-A-9-194667 and JP-A-9-27896
No. 8, JP-A-9-202843 and the like.

The thickness of the resin layer containing a water-soluble polymer as a main component in the present invention is not particularly limited, but is preferably 0.1 to 10 μm in consideration of gas barrier properties.
More preferably, it is 0.3 to 6 μm.

In the present invention, known methods can be used for forming the thermoplastic resin base film without any limitation. Specific examples include a T-die method and a tubular method in which a thermoplastic resin is melt-extruded and then cooled to obtain an unstretched film, and a method of further stretching to obtain a stretched film. Considering mechanical properties and the like, it is preferable that the film is a stretched film.

The above stretching methods include longitudinal or transverse uniaxial stretching, longitudinal and transverse sequential biaxial stretching, simultaneous biaxial stretching, rolling,
A method in which a sheet formed by calendering is continuously stretched in at least one direction is exemplified. Among these stretching methods, in consideration of thickness / thinness accuracy, mechanical properties, and the like, a longitudinal and transverse sequential biaxial stretching method and a tenter method simultaneous biaxial stretching method are preferable.

Examples of the laminating method for laminating a resin layer containing a water-soluble polymer as a main component on a thermoplastic resin base film include an extrusion laminating method and a method of laminating a molten resin on a vertically uniaxially stretched sheet. Are laminated and then subjected to lateral stretching, an in-line lamination method, a solution or solvent dispersion coating method, and the like.

In consideration of high-speed thin film coating, a coating solution obtained by dissolving or dispersing a resin containing a water-soluble polymer as a main component in various solvents is preferably used for gravure coating, reverse coating, spray coating, and kiss coating. coat,
It is preferable to perform gravure coating in combination with die coating, metaling bar coating, and chamber doctor. In the coating method, either in-line coating or off-line coating, in which the film is coated on a longitudinally uniaxially stretched sheet and then horizontally stretched, or subsequently coated after stretching, may be employed. Off-line coating is preferred in consideration of easy control of drying conditions and small turn.

The coating solution containing a resin containing a water-soluble polymer as a main component is preferably a coating solution in which the resin component is uniformly dissolved or dispersed in a solvent. As the solvent, water or a mixed solvent of water / lower alcohol is used, and in consideration of adhesiveness and productivity, it is preferable to use a mixed solvent of water / lower alcohol. The lower alcohol is an alcoholic compound having 1 to 3 carbon atoms, and specifically, methanol, ethanol, n- or iso-propanol is preferred. The mixing ratio of water / alcohol is 99% by weight.
/ 1 to 20/80.

In order to enhance the suitability for coating the thermoplastic resin substrate film, other water-soluble organic compounds may be added to the above-mentioned coating solution as long as the stability of the coating solution is not impaired. . Specifically, in addition to the lower alcohols used as the solvent, glycols such as ethylene glycol and propylene glycol, glycol derivatives such as methyl cellosolve, ethyl cellosolve, and n-butyl cellosolve, and polyhydric alcohols such as glycerin and waxes And ethers such as dioxane and trioxane; esters such as ethyl acetate; ketones such as methyl ethyl ketone; and aqueous anchor coating agents such as aqueous isocyanate, polyethyleneimine and epoxy resin.

The pH of the coating solution is preferably 2 to 11 in consideration of the stability of the coating solution.

The method of preparing the coating liquid is not particularly limited, but after a water-soluble polymer is uniformly dissolved or dispersed in a solvent, a liquid material in which components other than the water-soluble polymer are uniformly dissolved or dispersed is used. And the like.

Although the use of the laminated film of the present invention is not particularly limited, it is suitable as a food packaging film such as a gas barrier film.

[0052]

According to the method for producing a laminated film of the present invention, a specific surface treatment is applied to the surface of a thermoplastic resin substrate film to obtain a surface-treated substrate film excellent in handling suitability without blocking or the like. When laminated with a resin layer containing a water-soluble polymer as a main component, it has strong adhesiveness without providing an adhesive layer such as a special anchor coating agent. Therefore, the laminated film obtained by the method of the present invention is not only suitable as a gas barrier film but also widely useful as a food packaging film.

[0053]

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

The resin and film properties, surface treatment methods, and the like in the following Examples and Comparative Examples were performed by the following methods.

(1) Measurement of Main Peak by DSC About 5 to 6 mg of a sample was weighed, sealed in an aluminum pan, and heated from room temperature to 235 ° C. in a nitrogen flow of 20 ml / min with a differential calorimeter. Hold at this temperature for 10 minutes, then cool to room temperature at 10 ° C / min. Thereafter, a main peak was measured from a melting curve obtained at a heating rate of 10 ° C./min.

(2) Melt flow rate (MFR) Measured according to JIS K7210.

(3) Transparency (haze) Measured according to JIS K6714.

(4) Corona Discharge Treatment Surface treatment was performed using a corona discharge treatment tester manufactured by Kasuga Electric Co., Ltd. under the following conditions.

Introduced gas: Nitrogen Oxygen concentration: 5% by volume or less Film running speed: 10 m / min Electrode: Quartz electrode Electrode-film distance: 1.0 mm Generator: AGI-020 manufactured by Kasuga Electric Co. Processing temperature: 23 ° C. Effective processing Width: 300 mm (5) Flame plasma treatment A surface treatment was performed using a flame plasma tester manufactured by Flynn Burner (US) under the following conditions.

Fuel: Natural gas (air mixture) Burner output: 500 to 1300 kcal / inch / hr (burner burner 1 inch, calorie burned per hour) Flame in the flame-film surface distance: 2 mm Film running speed: 100 m / Min Cooling roll temperature: 38 ° C Effective treatment width: 600 mm (6) Blocking The two base films (12 × 12 cm) are superimposed on the surface opposite to the surface-treated surface, and a load of 10 kg is applied to the entire surface. It was left for 24 hours in an atmosphere of 90 ° C. and a humidity of 90% RH. A sample is cut out so that an overlapped portion having a width of 30 mm and a length of 40 mm and a margin for gripping the chuck (each film is gripped by the upper and lower chucks) remain, and a tensile tester (tensile speed: 100 mm / min, distance between chucks 40 m)
m), the shear peel strength was measured, and the blocking property was evaluated according to Table 1.

[0061]

[Table 1]

(7) Unevenness of treatment In the width direction of the surface-treated surface of the substrate film, a wetting reagent is applied so as to have a width of about 20 mm and a length of about 200 mm, and a ratio of a minimum wetting width to a maximum wetting width after about 2 seconds ( (Minimum wetting width / Maximum wetting width). The evaluation place was changed and the average value of five measurements was taken. When the above ratio was less than 0.6, it was evaluated that there was processing unevenness.

(8) Surface Roughness (Ra) Using a scanning probe microscope (NanoScope IIIa) manufactured by Digital Instruments, the surface roughness was measured under the following conditions, and the center line surface roughness was determined by averaging several times.

Mode: Tapping mode AFM Scanning range: 10 μm × 10 μm Probe radius: 5 to 10 nm Probe material: Single crystal silicon Scanning speed: 1.5 Hz cantilever free amplitude; 1.5 V cantilever set point; 1.1 Resonant frequency of ~ 1.3 V cantilever; 300 kHz (9) Oxygen barrier properties Measured using an oxygen permeability measuring device (manufactured by mocon; OX-TRAN100) according to JIS K7126 B method. The measurement was performed at 27 ° C.

(10) Adhesiveness a method) The base film surface was manually coated with a bar coater so as to have a coat thickness of 5 μm (when dried).
Let dry. After leaving at room temperature for one day or more, a cut having a width of about 30 mm was made in the center of the coated surface of the obtained laminated film in a direction perpendicular to the flow direction of the film. From the cut on the coated surface, a length of about 50
mm cellophane adhesive tape (manufactured by Nichiban Co., Ltd.) was applied and pressed with a finger, and a peeling test was performed in the upper 90 ° direction. The measurement was carried out 10 times, and the evaluation was performed according to Table 1.

[0066]

[Table 2]

Method b) The surface of the substrate film was manually coated with a bar coater to a coating thickness of 5 μm (when dried) and dried. After standing at room temperature for one day or more, a sample having a width of 15 mm was cut out in the flow direction of the obtained laminated film and subjected to a 180 ° peeling test using a tensile tester. The measurement site was changed three times or more under conditions of 20 mm between the chucks and the pulling speed of 100 m / min to obtain an average value of the peel strength.

Example 1 A resin containing the additives shown in Tables 3 and 4 was extruded into a sheet while being heated and melted at 280 ° C. using a T-die extruder, and cooled and solidified on a chill roll. By 5
The film was longitudinally stretched by a factor of 2 and subsequently transversely stretched by a factor of 8 with a tenter transverse stretching machine. Thereafter, a corona discharge treatment (treatment density: 90 W · min / m) was performed on one side of the film in a nitrogen gas atmosphere.
² ) and then flame plasma treatment (treatment intensity;
6.8 kcal / m ² ) to obtain a surface-treated base film of 20 μm. An EvOH coating agent (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; Soarnol 20L) heated to 40 ° C. was manually coated on the surface-treated surface of the obtained base film with a bar coater, dried at 100 ° C. for 5 minutes, and further cooled to room temperature For more than one day to obtain a laminated film. Tables 4 and 5 show various evaluation results.

Example 2 Using resins containing the additives shown in Tables 3 and 4, Table 4
A laminated film was obtained in exactly the same manner as in Example 1 except that the surface treatment shown in (1) was performed. Evaluation was performed in the same manner as in Example 1, and the results are shown in Tables 4 and 5.

Example 3 A laminated film was obtained in exactly the same manner as in Example 1 except that the surface treatment shown in Table 4 was performed. Evaluation was performed in the same manner as in Example 1, and the results are shown in Tables 4 and 5.

Example 4 Using a multilayer T-die extruder, extruded into a sheet under heating and melting at 270 ° C., solidified by cooling on a chill roll, and then longitudinally stretched 5 times by a heating roll stretching machine, followed by a tenter. The film is transversely stretched 8 times by a stretching machine and has a C / B / C configuration of 30 μm.
m (2/26/2 μm) was obtained. Then, the surface treatment shown in Table 4 was performed, and a laminated film was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.

Example 5 10 w of PVA (manufactured by Nippon Synthetic Chemical Industry; Gohsenol NL-05, saponification degree of 98.5% or more) was used as a coating agent.
A laminated film was obtained in exactly the same manner as in Example 1, except that a t% water / isopropanol solution (water: isopropanol volume ratio; 9: 1) was used and the surface treatment shown in Table 4 was performed. Evaluation was performed in the same manner as in Example 1, and the results were shown in Tables 4 and 5
It was shown to.

Comparative Example 1 A laminated film was obtained in exactly the same manner as in Example 5 except that the surface treatment shown in Table 4 was performed. Evaluation was performed in the same manner as in Example 5, and the results are shown in Tables 4 and 5.

Comparative Examples 2 and 3 A laminated film was obtained in exactly the same manner as in Example 1 except that the surface treatment shown in Table 4 was performed. Evaluation was performed in the same manner as in Example 1, and the results are shown in Tables 4 and 5.

[0075]

[Table 3]

[0076]

[Table 4]

[0077]

[Table 5]

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[Procedure amendment]

[Submission date] September 2, 1999 (1999.9.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

[0001] The present invention relates to a method for producing a laminated film suitable as a packaging film. Specifically, it is a method for producing a laminated film having good gas barrier properties.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

On the other hand, the method disclosed in JP-A-55-146747 is a method for producing a composite film in which a vinylpyrrolidone polymer is laminated on the surface-treated surface of a polyolefin film subjected to the above-mentioned surface treatment. Is only a corona treatment, and the corona treatment is carried out in the atmosphere. Thus, the corona treatment under the atmosphere, even
The film subjected to frame plasma treatment, there is still room for improvement with respect to adhesion to the water-soluble polymer.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention is applied to at least one surface of the thermoplastic resin base film, and corona discharge treatment in an atmosphere of nitrogen and / or carbon dioxide, the surface treatment consisting of both the frame plasma treatment Thereby, even if a resin layer mainly composed of a water-soluble polymer is directly laminated on the surface-treated surface without providing an adhesive layer such as a special anchor coat agent, the resin layer adheres firmly, and is preferable. A laminated film having gas barrier properties can be obtained, and its effectiveness is very high.

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[Correction target item name] 0014

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Further, the present invention exerts a particularly remarkable effect when an olefin resin , particularly, polypropylene is used as a raw material resin for the base film.

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[Correction target item name] 0063

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(8) Surface Roughness (Ra) Using a scanning probe microscope (NanoScope IIIa) manufactured by Digital Instruments, the surface roughness was measured under the following conditions, and the center line surface roughness was determined by averaging several times . What
The surface roughness (Ra value) of the surface to be treated of the film of the present invention
Indicates a range of 0.5 to 100 nm.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D075 BB49X CA42 DA04 DB31 DB36 DC36 EA06 EA07 EB19 4F006 AA02 AA12 AA13 AA15 AA16 AA17 AA19 AA35 AA36 AA38 AA39 AA40 AB03 AB20 AB24 BA01 BA05 BA03 BA03 A03 DA04 BB01 CA01 CA21 CA63 CA64 HA14 4F100 AK01A AK01B AK07 AK69 AT00A BA02 BA10A BA10B CC01 EJ37 EJ52 EJ55 EJ58 EJ64 GB15 JB09B JB16A JD02

Claims (1)

[Claims] At least one surface of a thermoplastic resin base film is subjected to a corona discharge treatment in a nitrogen and / or carbon dioxide gas atmosphere and a surface treatment comprising flame plasma treatment. A method for producing a laminated film, comprising laminating a resin layer mainly composed of a polymer.