Polymeric film

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to polymeric films, especially coated polymeric films.

【0002】

[Problems to be solved by conventional techniques and inventions]

Polymer films containing layered minerals are known. Layered minerals have been used to impart various properties to polymer films, such as flame retardancy, antistatic properties and barrier properties of gases, especially oxygen. This is disclosed in, for example, Japanese Patent Application Laid-Open No. 62-181144, EP-A-235926 and US-A-3,499,820. Unfortunately, the films often had insufficient adhesion of layered minerals to the polymer substrate.

【0003】

Japanese Patent Application Laid-Open No. 63-233836 discloses a film having a barrier property against steam and gas, and this film contains a thin layered silicate and a vinylidene chloride resin. However, there is currently a commercial demand for materials that are more environmentally acceptable than vinylidene chloride resins.

【0004】

The present inventors have invented a coating film having a layered mineral capable of exhibiting oxygen barrier properties and an improved adhesiveness of the layered mineral film layer to a substrate.

【0005】

[Means for Solving Problems and Effects of Invention]

Therefore, the present invention is a polymer film having a base layer of a polymer material and a coating layer formed of a composition containing a layered mineral and a cross-linking agent on at least one surface of the base layer. It contains a layer of layered minerals of more than 10% by weight and less than 90% by weight and a resin layer obtained from a cross-linking agent of more than 10% by weight and less than 90% by weight, wherein the cross-linking agent is an epoxy resin, an alkyd resin, an amine derivative, and the like. And at least one selected from the group consisting of condensation products of amines and aldehydes, and said layered minerals include vermiculite platelets, more than 50% of which have a particle size in the range of 0.5-5.0 microns. Provided is a polymer film characterized by.

【0006】

The present invention is a method for producing a polymer film by a step of forming a base layer of a polymer material and a step of adhering a coating layer formed of a composition containing a layered mineral and a cross-linking agent to at least one surface thereof. The coating layer contains a layer of layered minerals of more than 10% by weight and less than 90% by weight and a resin layer obtained from a cross-linking agent of more than 10% by weight and less than 90% by weight, and the cross-linking agent is an epoxy resin. , Alkid resins, amine derivatives, and at least one selected from the group consisting of condensation products of amines and aldehydes, and said layered minerals, more than 50% of which have a particle size in the range of 0.5-5.0 microns. Also provided is a method of making a polymer film comprising a vermiculite crosslink having.

【0007】

The substrate used in the production of the coated polymer films of the present invention appropriately comprises any polymer material capable of forming a self-supporting, opaque or preferably transparent film or sheet.

【0008】

"Self-supporting film or sheet" means a film or sheet that can exist independently without a supporting substrate.

【0009】

The substrate for the coating film of the present invention can be formed from any film-forming polymer material. Suitable thermoplastics, synthetic materials are 1-olefins such as ethylene, propylene or butene-1, especially homopolymers or copolymers of propylene, polyamides, polycarbonates, and especially synthetic linear polyesters. The synthetic linear polyester is one or more dicarboxylic acids or their lower alkyl (6 or less carbon atoms) diesters such as terephthalic acid, isophthalic acid, phthalic acid, 2,5-, 2,6- or 2, 7-naphthalenedicarboxylic acid, succinic acid, sebacic acid, adipic acid, azelaic acid, 4,4'-diphenyldicarboxylic acid, hexahydro-terephthalic acid, or 1,2-bis-p-carboxyphenoxyetane (optionally mono) Carboxylic acid, eg pivalic acid), 1 or more glycols, especially aliphatic glycols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol and 1 , 4- Obtained by condensing with cyclohexanedimethanol.

【0010】

A polyethylene terephthalate film is particularly preferable, and in particular, as described in, for example, British Patent No. 838,708, it is preferably sequentially stretched in two directions perpendicular to each other at a temperature of 70 to 125 ° C and biaxially oriented. Is preferably a film heat-set at a temperature of 150 to 250 ° C.

【0011】

The substrate may consist of a polyaryl ether or a thio counterpart thereof, in particular a polyaryl ether ketone, a polyaryl sulfone, a polyaryl ether ether ketone, a polyaryl ether ether sulfone, or a copolymer thereof or a thio counterpart thereof. .. Examples of these polymers are disclosed in EP-A-1879, EP-A-184458 and US-A-4008203, and particularly suitable materials are those sold by IGIPLC under the registered trademark STABAR. .. The substrate may consist of poly (allylensulfide), in particular poly-p-phenylenesulfide or a copolymer thereof. Blends of the polymers may also be used.

【0012】

Suitable thermocurable resin substrate materials include addition polymerization resins such as acrylic resins, vinyl resins, bismaleimide resins and unsaturated polyesters, formaldehyde condensed resins such as condensates with urea, melamine or phenol, cyanate resins, functionalization. There are polyester polyamide or polyimide.

【0013】

The polymer film substrate for the production of the coating film of the present invention may be unstretched or uniaxially stretched, but is preferably perpendicular to each other in the film plane in order to obtain a satisfactory combination of mechanical and physical properties. It stretches in two directions and is biaxially oriented. Simultaneous biaxial orientation is performed by extruding a thermoplastic polymer tube, which is then quenched and reheated, then laterally oriented by internal gas pressure and pulled at a rate that causes vertical orientation. sell. Sequential stretching can be performed by a tenter method in which the thermoplastic substrate material is extruded flat, followed by first stretching in one direction and then in the other directions perpendicular to each other. In general, it is preferable to first stretch the film in the longitudinal direction, that is, in the traveling direction by a film stretching machine, and then stretch it in the lateral direction. The stretched substrate film may have better dimensional stability by constraining the dimensions and heat-setting at a temperature higher than the glass transition temperature, which is preferable.

【0014】

The thickness of the substrate is 6 to 300 μm, particularly 6 to 100 μm, and more preferably 6 to 25 μm.

【0015】

A "crosslinking agent" is a chemical reaction during the formation of a coating layer to form a polymeric resin, preferably forming a covalent bond with both itself and the underlying surface to form a crosslink. Means a material that improves adhesion to the surface. The cross-linking agent is an organic material, preferably a monomer and / or oligomer species, particularly preferably a monomer species, prior to the formation of the coating layer. The molecular weight of this cross-linking agent is preferably less than 5000, more preferably less than 2000, particularly preferably less than 1000, and particularly preferably 250-500. In addition, the crosslinker should preferably be internally crosslinkable to provide protection against solvent penetration.

【0016】

Suitable cross-linking agents include epoxy resins, alkyd resins, amine derivatives such as hexamethoxymethylmelamine, and / or amines such as melamine, diazine, urea, cyclic ethyleneurea, cyclic propylene urea, thiourea, cyclic ethylenethiourea, aziridine. , Alkyl melamines, aryl melamines, benzoguanamines, guanamines, alkyl guanamines and aryl guanamines, and aldehydes, for example, condensation products of formaldehyde. A preferred cross-linking agent is a condensation product of melamine and formaldehyde. The condensation product may optionally be alkoxylated. It is also preferable to use a catalyst to promote the cross-linking action of this cross-linking agent. Preferred catalysts for cross-linked melamine formaldehyde include paratoluenesulfonic acid, maleic acid stabilized by reaction with a base, and morpholine paratoluenesulfonic acid.

【0017】

Layered minerals preferably include platelets of film-forming 2: 1 phyllosilicate layer minerals. Clay Minerals: Their Structure, Behavior & Use, Proceedings of Royal Society Discussion Meeting, 9 & 10 November 1983, London, The Royal Society, 1984 (especially) Refer to pages 222 to 223 and 232 to 235).

【0018】

The term "platelet" is used herein to chemically separate layered minerals (which can form a film from this aqueous colloidal dispersion) to form an aqueous colloidal dispersion of high aspect ratio particles of this mineral. It is used to mean small particles of layered minerals obtained during the layering process.

【0019】

Preferably, the layered mineral is selected from the group consisting of smectites (preferably hectorite and montmorillonite) and in particular vermiculite.

【0020】

The term "vermiculite" is used herein to mean all materials known mineralogically and commercially as vermiculite. Vermiculite ore is a naturally occurring mineral, a mixture of phases (eg vermiculite, biotite, hydrobiotite, etc.) and interlayer cations (eg Mg).²⁺, Ca²⁺, K⁺) Is included. The formation of an aqueous suspension or slurry of vermiculite platelets relies on ion exchange (usually incomplete) to produce proper macroscopic swelling. The swollen, fully or partially ion-exchanged vermiculite gel can then be milled to produce a film-forming aqueous suspension of vermiculite platelets. It is well known that vermiculite particles are treated with one or more aqueous solutions of metal (particularly alkali metal) salts or alkylammonium salts, then swollen in water and then finely ground to delaminate vermiculite, eg GB. -A-1016385, GB-A-1119305, GB-A-1585104. It is described in GB-A-1593382 and US-A-4130687.

【0021】

Vermiculite is a particularly suitable layered mineral when a coating film exhibiting gas barrier properties, especially oxygen barrier properties, is required. The coating film of the present invention has an oxygen permeability of 50 cc / m.²Less than / day, preferably 20cc / m²Less than / day, more preferably 10cc / m²Less than / day, especially preferably 5cc / m²Less than / day, especially preferably 1cc / m²It is appropriate that it is less than / day.

【0022】

A preferred embodiment of the present invention is a particle size of more than 50%, preferably 55-99.9%, more preferably 60-99%, particularly preferably 70-95% of the number of vermiculites (maximum width dimension of vermiculite). Includes a coating layer of vermiculite platelets with a size of 0.5-5.0 μm. It is also preferred that 80-99.9%, more preferably 85-99.9%, particularly preferably 90-99.9% of the number of vermiculite platelets have a particle size of 0.1-5.0 μm. The average particle size of the vermiculite platelet (which means the average value of the maximum width of the platelet) is preferably 1.0 to 3.0 μm, more preferably 1.2 to 2.2 μm, and particularly preferably 1.3 to 1.6 μm.

【0023】

The thickness of the vermiculite platelet is preferably about 10-60 Å, especially about 25-40 Å. In addition, 60-100%, more preferably 70-99%, particularly preferably 90-95% of the number of vermiculite platelets is preferably 10-60 Å thick. The average thickness of the vermiculite platelet is preferably 25 to 50 Å, more preferably 25 to 40 Å, and particularly preferably 25 to 30 Å.

【0024】

The coating layer may have a substantially continuous platelet layer of any practical thickness, preferably up to 5 μm, preferably up to 2 μm, more preferably up to 0.2 μm, but with desirable properties such as, for example. The coating film, which exhibits a surprisingly improved barrier to atmospheric oxygen, is substantially continuous at very thin thicknesses, such as up to 0.01 μm, especially 0.02 to 0.2 μm, especially 0.025 to 0.1 μm. Platelet layer.

【0025】

The coating layer is preferably a layer of resin obtained by cross-linking with a cross-linking agent in an amount of more than 20% by weight and less than 80% by weight, more preferably more than 25% by weight and less than 70% by weight, and particularly preferably more than 30% by weight and less than 60% by weight. Particularly preferably, it contains more than 30% by weight and less than 50% by weight. The coating layer preferably comprises a layered mineral layer of more than 20% by weight and less than 80% by weight, more preferably more than 30% by weight and less than 75% by weight, particularly preferably more than 40% by weight and less than 70% by weight, particularly preferably 50%. Includes more than 70% by weight and less than 70% by weight.

【0026】

In a preferred embodiment of the invention, the coating layer additionally comprises a copolymer of 1-olefin and vinyl monomer. Suitable 1-olefins include ethylene, propylene and butene-1. Ethylene is particularly preferred. The vinyl monomer is preferably a vinyl ester such as vinyl chloroacetate, vinyl benzoate, and especially vinyl acetate. Ethylene / vinyl acetate copolymers are particularly preferred. The ratio of the amount of 1-olefin to vinyl monomer present in this copolymer is preferably 5: 1 to 1: 5, more preferably 4: 1 to 1: 2, and particularly preferably 3: 1 to 1: 1.

【0027】

The presence of a copolymer of 1-olefin and vinyl monomer in the coating layer, surprisingly, further improves the adhesion of the layered mineral coating layer to the polymer substrate. The amount of the copolymer of 1-olefin and vinyl monomer is preferably 1 to 30%, more preferably 2 to 20%, particularly preferably 2.5 to 15%, particularly preferably 2.5 to 4% of the weight of the coating layer. is there. The copolymer of 1-olefin and vinyl monomer is preferably mixed with the layered mineral before adding the crosslinker to the coating composition.

【0028】

A coating layer by applying a coating composition containing a layered mineral platelet, a cross-linking agent and preferably a copolymer of 1-olefin and vinyl monomer as a slurry or dispersion and removing the dispersion medium to form a cohesive layer. To form. Preferably, the dispersion medium consists of water and the slurry or dispersion comprises 0.5-20% by weight, more preferably 1-10% by weight of a platelet of layered minerals.

【0029】

The coating layer composition can be applied before, during or after the stretching operation in the production of the alignment film. The coating layer composition can be applied to the film substrate, for example, during two steps (longitudinal and lateral) of the thermoplastic film biaxial stretching operation. Such an order of stretching and coating would be suitable for the production of coated linear polyester film substrates. The film is preferably first stretched longitudinally through a series of rotating rollers, coated, then laterally stretched in a tenter oven, and preferably subsequently heat-set. The coating composition is preferably applied to a film substrate that has already been oriented, such as a biaxially oriented polyester, particularly polyethylene terephthalate, and is preferably heated.

【0030】

The temperature at which the coated film is heated depends, among other things, on the composition of the polymer substrate. The coated polyester (particularly polyethylene terephthalate) substrate is an aqueous medium, or in a solvent-coated composition, to dry the solvent, and to allow cross-linking of this layer to occur, and also. It is appropriate to heat to 100-240 ° C, preferably 160-220 ° C, to help the film fuse and form a continuous uniform layer. .. In contrast, coated polyolefins (particularly polypropylene) are suitable for heating to 85-95 ° C.

【0031】

The coating layer composition is preferably applied to the polymer film substrate by any suitable conventional method. This conventional method includes dip coating, bead coating, reverse roller coating or slot coating.

【0032】

The coating weight of the coating layer on the polymer substrate is preferably 0.25 to 100 mgdm.^-2, More preferably 0.5-40 mgdm^-2, Especially preferably 1.0 ~ 20.0 mgdm^-2Is. For films coated on both sides, the coating weight of such layers is in the preferred range.

【0033】

In a preferred embodiment of the invention, an additional primer layer is applied to the substrate layer prior to coating with the layered mineral coating layer. The present invention provides a surprising improvement in oxygen barrier properties in the presence of polymer film primers.

【0034】

At least one polymer that may be any polymer known in the art as capable of forming a continuous, preferably uniform coating, being adhesive to a supporting substrate, and preferably having optical transparency. The primer layer contains a polymer resin.

【0035】

Suitable polymeric resins include:

【0036】

(a) An "aminoplast" resin that can be prepared by the reaction of amines or amides, which are typically alkoxylation condensation products of melamine and formaldehyde, such as hexamethoxymethylmelamine formaldehyde, trimethoxytrimethylolmelamine formaldehyde; [0037]

(b) Homopolyester, eg polyethylene terephthalate; [0038]

(c) Copolyesters, especially those derived from sulfo derivatives of dicarboxylic acids, such as sulfotererephthalic acid and / or sulfoisophthalic acid; [0039]

(d) Copolymers of styrene with one or more ethylenically unsaturated comonomer, such as maleic anhydride or itaconic acid, especially the copolymers described in GB-A-1540067; [0040]

(e) Copolymers of acrylic acid and / or methacrylic acid and / or their lower alkyl (6 or less carbon atoms) esters, such as copolymers of ethyl acrylate and methyl methacrylate, copolymers of methyl methacrylate / butyl acrylate / acrylic acid, representatives. The molar ratio is 55/27/18% and 36/24/40%; [0041]

(f) Styrene / acrylamide copolymers, especially those of the type described in GB-A-1174328 and GB-A-1134876; [0042]

(g) Functionalized polyolefins, especially maleated polybutadiene; [0043]

(h) Cellulose materials such as nitrocellulose, ethyl cellulose and hydroxyethyl cellulose; [0044]

(i) Polyvinyl alcohol.

【0045】

Preferred resin components of the primer layer are acrylamide and / or derivatives thereof, such as lower alkyl, preferably n-butoxy derivatives, and / or methacrylamide and / or derivatives thereof, such as lower alkoxy, preferably n-butoxy derivatives, and them. Includes at least one other ethylenically unsaturated comonomer that is copolymerizable with. Examples include acrylic acids and their esters such as alkyl esters such as methyl acrylates, ethyl acrylates, butyl acrylates, 2-ethyl-hexyl acrylates, isobutyl acrylates, hexyl acrylates and octyl acrylates; methacrylic acid and its esters such as methyl. There are copolymers of methacrylates, ethyl methacrylates and butyl methacrylates. Other suitable monomers include acrylonitrile, styrene, monomethylstyrene, vinyltoluene, maleic anhydride and vinyl esters. Styrene and alkyl acrylates are particularly preferred monomers. Dienes, such as butadiene or chloroprene, may also be present in the primer layer copolymer.

【0046】

The primer layer preferably contains at least one free functional acid group (eg, a pendant carboxyl group or a sulfonate group). It is a group that does not participate in the polymerization reaction that forms the copolymer, such as acrylic acid, methacrylic acid, maleic acid and itaconic acid. Free functional acid group-containing comonomer up to 25% by weight, preferably up to 10% by weight, particularly preferably up to 5% by weight can be used.

【0047】

The polymer resin component of the primer layer is preferably derived from up to 90% by weight styrene, up to 80% by weight alkyl acrylate, up to 15% by weight methacrylic acid and 5-40% by weight of acrylamide and each amide group in the copolymer. Each contains a copolymer condensed with a butanol solution of styrene containing 0.2-3 g equivalent of styrene. Particularly preferred copolymers include styrene / 2-ethylhexyl acrylate / methacrylic acid / n-butoxymethylacrylamide, the ratio of which is 20-40 / 30-50 / 1-5 / 20-30 wt%. GB-A-1174328 and GB-A-1134876 describe suitable synthetic methods for the primer layer copolymers described above.

【0048】

The polymer resin of the primer layer is preferably compatible with and contains additional acidic components (eg, sulfuric acid, nitric acid, acetic acid or any mineral acid, such as hydrochloric acid) in the primer layer coating composition. The additional acidic component is preferably present in the primer layer coating composition at a concentration of 0.5 to 15, more preferably 1 to 10, particularly preferably 4 to 8% by weight, with respect to the polymeric resin. Sulfuric acid is the preferred acidic component.

【0049】

The molecular weight of the polymer resin in the primer layer can range over a wide range, but the weight average molecular weight is preferably 10,000 to 300,000, more preferably 15,000 to 100,000.

【0050】

The polymer of the primer layer coating composition is generally water insoluble. However, the primer layer composition containing the water-insoluble polymer can be applied to the polymer film substrate as an aqueous dispersion or an organic solvent solution.

【0051】

The primer layer coating material can be applied before, during or after the stretching operation. In particular, the coating material can be applied to the film substrate during the two stages (longitudinal and horizontal) of the biaxial stretching operation. Such a stretching and coating sequence is suitable for the production of coated linear polyester film substrates, such as coated polyethylene terephthalate films. This preferably involves first stretching the film through a series of rotating rollers, applying it, then stretching it laterally in a tenter oven, and preferably subsequently heat setting.

【0052】

The primer layer coating composition is applied to the polymer film as an aqueous dispersion or an organic solvent solution by either a suitable conventional coating method, for example, dip coating, bead coating, reverse roller coating or slot coating. Can be applied.

【0053】

The primer layer coating material is preferably applied to an already oriented film substrate, such as a biaxially oriented polyester, particularly a polyethylene terephthalate film.

【0054】

Prior to placing the primer layer or coating layer on the polymer substrate, if desired, the surface of the substrate is chemically or physically surface-modified, and the surface and the primer layer or coating layer attached thereafter are subjected to surface modification treatment. The adhesiveness between them may be improved. Due to its simplicity and effectiveness, a preferred treatment particularly suitable for treating polyolefin substrates is to apply high voltage electrical stress to the exposed surface of the substrate by corona discharge. Alternatively, the substrate may be pretreated with a treatment agent known in the art to exert a solvent or swelling effect on the substrate polymer. Examples of such treatments that are particularly suitable for the treatment of polyester substrates are halogenated phenols dissolved in ordinary organic solvents, such as p-chloro-m-cresol, 2,4-dichlorophenol, 2,4,5. -Or contains 2,4,6-trichlorophenol or 4-chlororesorcinol in acetone or methanol.

【0055】

The primer layer is preferably applied to a polymer substrate with a weight of 0.1 to 10 mgdm.^-2, Especially 1.0 ~ 6mgdm^-2Apply with. For films coated on both sides, each layer preferably has a coating weight within the preferred range described above.

【0056】

Degeneration of the surface of the primer layer, such as flame treatment, ion shock, electron beam treatment, UV treatment or preferably corona discharge treatment, will improve the adhesion of the coating layer containing the layered minerals subsequently applied, but is satisfactory. It may not be indispensable to obtain a good bond.

【0057】

The preferred treatment by corona discharge can be carried out in air under atmospheric pressure with a conventional device using a high frequency high voltage generator, preferably with a voltage of 1 to 100 KV and an output of 1 to 20 KW. Discharge is conveniently carried out by passing the film through an insulating support roller of the discharge station, preferably at a linear velocity of 1.0 to 500 m / min. The discharge electrode may be located 0.1 to 10.0 mm from the moving film surface.

【0058】

The thickness of the primer layer relative to the thickness of the substrate can vary over a wide range, but the thickness of the primer layer should preferably be 0.004% or more and 10% or less of that of the substrate. In fact, the thickness of the primer layer is preferably at least 0.005 μm and should not be much greater than 1.0 μm.

【0059】

An additional overcoat layer may be applied on top of the coating layer. The overcoat layer may be any suitable film-forming polymer resin, and for example, those described here as those used for the primer layer.

【0060】

The polymer films described herein are suitable as packaging films, especially when a polyethylene film is laminated as an overcoat layer. This polyethylene film is preferably adhered to the polymer film of the coating layer by an intermediate adhesive layer, particularly a polyurethane layer.

【0061】

One or more of the layers of the polymer film of the present invention, namely the substrate layer, the primer layer, the coating layer and / or the overcoat layer, may conveniently contain any of the additives conventionally used in the production of polymer films. Is. Therefore, dyes, pigments, pore-forming agents, lubricants, antioxidants, anti-blocking agents, surfactants, slip aids, gloss improvers, prodegradants, UV stabilizers, viscosity modifiers, and dispersion stabilizers. Additives such as agents may be added to the substrate and / or coating layer as appropriate. In particular, the substrate may contain a small particle size granular filler (eg silica). If used in the substrate layer, the filler should preferably be present in a small amount of 0.5% or less, preferably 0.2% or less of the weight of the substrate.

【0062】

The present invention will be described with reference to the accompanying drawings.

【0063】

FIG. 1 is a schematic cross-sectional view that is not proportional to the actual dimensions of the coating film having the substrate layer and the coating layer.

【0064】

FIG. 2 is a similar schematic cross-sectional view of a coating film having an additional primer layer between the substrate layer and the coating layer.

【0065】

FIG. 3 is a similar schematic cross-sectional view of the film shown in FIG. 2 having an additional overcoat on the distant surface of the coating layer.

【0066】

In FIG. 1, the film comprises a coating layer 2 in which a polymer substrate layer 1 is bonded to one of its surfaces 3.

【0067】

The film of FIG. 2 contains an additional primer layer 4 bonded to the surface 3 of the substrate layer 1 and the surface 5 of the coating layer 2.

【0068】

The film of FIG. 3 further comprises an additional overcoat layer 6 bonded to the distant surface 7 of the coating layer 2.

【0069】

[Example]

The present invention will be further described below with reference to examples.

【0070】

The following test method was used.

【0071】

Adhesion test The adhesiveness of the coating layer to the substrate, or that of the coating layer to the primer layer and that of the primer layer to the substrate was measured by the following method. Two strips of adhesive tape were placed on the coating layer of the film and the back of the tape was rubbed up and down three times to bond. The first strip of adhesive tape was slowly peeled back to the peel edge at 180 ° (= delayed). The second strip of adhesive tape was quickly peeled off directly from the film surface (= quick pull). Next, observe this film sample with a light box, and measure the amount of film removed as good (= no damage to the film with the naked eye), normal (= some damage to the film), and poor (= majority of the film). Is excluded), evaluated as.

【0072】

Oxygen barrier The oxygen permeability of the film was measured using a Mocon 1050 (Modern Controls Inc.) tester. A film sample was placed in the instrument and nitrogen carrier gas was run on both the top and bottom sides of the film for background reading. The nitrogen above the film was replaced with oxygen, and the amount of oxygen that could permeate the film was measured in carrier gas using a sensor.

【0073】

(Example 1) A vermiculite suspension was prepared by the following method: [0074]

100 g of vermiculite ore (ex-Carolina, US) was refluxed at 80 ° C. for 4 hours with 1 L of 1N lithium citrate solution and left at room temperature for 5 days. This resulted in the exchange of 45.3 mg equivalent of lithium cation in 100 g of ore. The ion-exchanged vermiculite ore was washed 5 times with deionized water to remove excess salt and left overnight to swell in a large volume (ie, 10 times the volume of vermiculite) deionized water. This swollen vermiculite was milled in a Greaves high shear mixer at 7200 rpm for 40 minutes to make a suspension of vermiculite platelets. The platelet suspension was then screened through a mechanically shaken filter with a pore size of 106 μm.

【0075】

The polyethylene terephthalate film was melt-extruded, cast on a cooled rotating drum, and stretched in the extrusion direction to about 3 times its original dimensions. The film was passed through a tenter oven, where it was stretched in the width direction to about 3 times its original dimensions. This biaxially stretched film was heat-set at about 220 ° C by a conventional method. The final film thickness was 23 μm.

【0076】

One side of this biaxially oriented polyethylene terephthalate film was coated with a coating layer composition consisting of the following components using a gravure coater: [0077]

[table 1] Vermiculite 16L (7.5% w / w water dispersion) Cymel 385 800mL (Melamine formaldehyde with a molecular weight of 348) Paratoluenesulfonic acid 100mL (10% w / w aqueous solution) Synperonic NP 10 150mL (10% w / w aqueous solution of nonylphenol ethoxylate (sold by ICI)) Make 20L of deionized water [0078]

This coating film is dried at 180 ° C, and the dry film weight of this coating layer is about 2 mgdm.^-2Met. The thickness of this coating layer was about 0.1 μm.

【0079】

The adhesiveness of the coating layer to the substrate was measured using the above-mentioned adhesion test and found to be "good" in both slow and fast pulling.

【0080】

When the oxygen barrier property of the coating film was measured by measuring the oxygen permeability, it was 9.5 cc / m.²/ It was a day. The oxygen permeability of the uncoated polyethylene terephthalate film was also measured and found to be 50.0 cc / m.²/ It was a day.

【0081】

(Example 2) The process of Example 1 was repeated except that one side of the biaxially oriented polyethylene terephthalate film was first coated with a primer layer material. This primer layer material stock solution is a solvent mixture of n-butanol / toluene / xylene in a weight% ratio of 19/78/3 and a styrene / ethylhexyl acrylate / methacrylic acid / n in a weight% ratio of 30.9 / 38.9 / 2.1 / 28.1. -Contains 50% by weight of polymer containing butoxymethylacrylamide. Prior to coating, the primer layer material stock solution was diluted to 4% by weight with isopropyl alcohol and 6% by weight of the polymer sulfuric acid was added. This primer layer material was coated with a gravure coater. After coating, the film is dried in a hot air oven kept at 90 ° C and the dry film weight is 1.0 mgdm.^-2And a film having a primer layer having a thickness of about 0.1 μm was obtained.

【0082】

Next, the coating layer composition described in Example 1 was coated on the primer layer of the polyethylene terephthalate film coated with this primer layer.

【0083】

When the adhesiveness of the coating layer to the primer layer and the adhesiveness of the primer layer to the substrate were measured by the above-mentioned adhesion test, both delayed and fast pulling were "good".

【0084】

When the oxygen barrier property of the film was measured by measuring the oxygen permeability, it was 0.5cc / m.²/ It was a day.

【0085】

(Example 3) This example is a comparative example that does not follow the present invention. The process of Example 2 was repeated except that the coating layer composition did not contain Cymel385 and p-toluenesulfonic acid.

【0086】

When the adhesiveness of the coating layer to the primer layer and the adhesiveness of the primer layer to the substrate were measured by the above-mentioned adhesion test, both delayed and fast pulling were "defective".

【0087】

(Example 4) The process of Example 1 was repeated except that the coating layer composition consisted of the following components.

【0088】

[Table 2] HTS-SE 8L (5% by weight relative to vermiculite) Contains ethylene / vinyl acetate copolymer Vermiculite 8.3% w / w water dispersion (According to inventor's analysis), WRGrace, (Obtained from Massachusetts) Cymel 385 450mL (Melamine formaldehyde with a molecular weight of 348) Paratoluenesulfonic acid 180mL (10% w / w aqueous solution) Synperonic NP 10 200mL (Nonylphenol ethoxylate (from ICI) Obtained) 10% w / w aqueous solution) Make 20L of deionized water [0089]

When the adhesiveness of the coating layer to the substrate was measured using the above-mentioned adhesion test, both delayed and fast pulling were "good".

【0090】

In addition, the adhesive strength of the coating layer to the substrate was measured in an additional test. In this test, polyurethane adhesives (polyurethane prepolymer (Product No. 10-2525 / 3) and polyhydric alcohols (Product No. 10-2526 / 3, both obtained from Holden Surface Coatings Ltd, England) were mixed. The coating layer was coated using a gravure system using () and dried at 80 ° C in a furnace, and the two films, the film and the polyethylene film, were passed through a nip heated to 120 ° C and polyethane. The films were laminated. Adhesion was measured by peeling the resulting laminate using an "Instron" test meter at a peel speed of 200 mm / min. Peel strength is 250g / 25mm (98Nm)^-1)Met. On the other hand, the laminate formed using the coating film made in Example 1 has a peel strength of 10 g / 25 mm (3.9 Nm).^-1)Met.

【0091】

The above example illustrates the improved properties of the coating film of the present invention.

【0092】

Preferred features [0093]

As mentioned herein, the polymeric films of the present invention exhibit the following preferred features-each independently or in any combination.

【0094】

1. The coating layer contains a layered mineral of more than 20% and less than 80% of the weight of this layer and a resin obtained from a cross-linking material of more than 20% and less than 80% of the weight of this layer.

【0095】

2. The coating layer additionally contains a copolymer of 1-olefin and vinyl monomer.

【0096】

3. The cross-linking agent has a molecular weight of less than 2000.

【0097】

4. Layered minerals include film-forming 2: 1 phyllosilicate plateslets.

【0098】

5.2: 1 Phyllosilicate contains vermiculite.

【0099】

6. There is a primer layer containing a polymer resin between the substrate and the coating layer.

【0100】

7. The primer layer is acidic.

【0101】

8. The primer layer contains a copolymer consisting of acrylamide and / or a derivative thereof and / or methacrylamide and / or a derivative thereof, and at least one other ethylenically unsaturated comonomer copolymerizable therewith.

[Simple explanation of drawings]

[Figure 1]

Schematic diagram of a cross section that is not proportional to the actual dimensions of a coating film having a substrate layer and a coating layer.

[Figure 2]

A similar schematic cross-sectional view of a coating film having an additional primer layer between the substrate layer and the coating layer.

[Fig. 3]

FIG. 2 is a similar schematic cross-sectional view of the film shown in FIG. 2 having an additional overcoat on the distant surface of the coating layer.

[Explanation of symbols]

1 ... Polymer substrate layer 2 ... Coating layer 3 ... one surface of polymer substrate layer 1 4 ... additional primer layer 5 ... Surface of coating layer 2 6 ... Overcoat layer