KR960000743B1 - Laminated polyester film - Google Patents

Abstract

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Description

Laminated polyester film

The present invention relates to a laminated polyester film having a cured layer formed by ultraviolet or irradiation.

In more detail, this invention relates to the laminated polyester film which improved the adhesive strength between each layer.

The biaxially oriented polyester film is excellent in transparency, dimensional stability, mechanical properties, heat resistance, electrical properties, gas barrier properties, chemical resistance, etc., so that packaging materials, electrical insulation materials, metal deposition materials, metal deposition materials, and plate making It is used for applications such as materials, magnetic recording materials, display materials, red sand materials and window stickers.

Until now, in these uses, the laminated | multilayer film which formed the coating layer by apply | coating a coating agent to the surface of a polyester film, drying, and performing thermosetting as needed was used. Recently, however, there has been a demand for low temperature treatment due to improvement of solvent-free coating solution, acceleration of coating layer formation, dimensional stability, etc., and the use of a coating agent that is polymerized and crosslinked and cured by ultraviolet rays or electron beams is used. It has been inspired. The curable paints are commercially available mainly for printing inks, insulation coatings for wiring waves, and so-called hard coat paints. In addition, new uses of this paint type, such as magnetic layer formation, are being studied.

However, this new technology has a problem of poor adhesion between the polyester film and the ultraviolet or electron beam curable coating layer. In order to solve this problem, the conventional method of forming an ultraviolet-ray or electron beam hardened layer by undercoat the biaxially stretched polyester film is used. However, this method has not only poor adhesion between each insect but also problems in production cost.

The present inventors have found that biaxially stretched polyester films having a specific applicator obtained by a coating and stretching method capable of producing a film having an applicator at a relatively low cost have good interlaminar adhesion. The present invention has been completed based on this finding.

SUMMARY OF THE INVENTION The gist of the present invention is a laminated polyester comprising a biaxially cultivated polyester film, a coating layer composed mainly of chlorine-containing polymer formed on at least one side of the biaxially oriented polyester film, and an ultraviolet or electron beam cured layer formed on the coating layer. Present in the film.

The polyester used in the present invention is polyethylene terephthalate or polyethylene naphthalate wherein at least 80 mole% of its constituent repeat units are ethylene terephthalate units or ethylene naphthalate units.

Preferably such polyesters have an intrinsic viscosity in the range of 0.55 to 0.75.

The polyester film used in the present invention may contain, as necessary, inorganic particles, organic particles, organic lubricants, antistatic agents, stabilizers, dyes, pigments, organic polymers, and the like. In order to impart slipperiness to the film, fine particles are contained in the polyester film. The type, size and amount of the fine particles are appropriately selected according to the required characteristics such as slipperiness and transparency of the product to be used.

Desired properties such as orientation, crystallinity, mechanical properties, dimensional stability, and the like can be realized by selecting manufacturing conditions known to those skilled in the art according to the required properties of the product in which the laminated polyester film of the present invention is used.

The chlorine-containing polymer used in the present invention is a homopolymer or copolymer of a chlorine compound having an active double bond, a copolymer of the chlorine compound with an olefin compound, a vinyl compound or an acrylic compound, and the chlorine compound having an active double bond. Copolymers prepared by grafting on resins such as ethylene-vinyl acetate copolymers and chlorine are obtained by reacting chlorine with polyethylene, polypropylene or polyvinyl chloride and α-olefins.

Chlorine compounds include vinylidene chloride, vinyl chloride and chloroprene. Olefin compounds include ethylene, propylene, butadiene and the like. Vinyl compounds include vinyl acetate, styrene, styrenesulfonic acid and salts thereof, vinyl sulfonic acid and salts thereof, vinyl sulfonamide, maleic acid and the like. Acrylic compounds include acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-methylol acrylamide, N-methyl acrylamide, N-methylol methacrylamide and methyl (ethyl , n-propyl, isopropyl, n-butyl, isobutyl, 2-ethylhexyl or stearyl) acrylate or methacrylate.

Among the chlorine-containing polymers described above, vinyl chloride homopolymers and copolymers, vinylidene chloride homopolymers and copolymers, chloroprene homopolymers and copolymers, copolymers of vinyl chloride with at least one vinyl acetate, acrylic compound and olefin compound Examples are vinyl chloride-vinyl acetate copolymers, vinyl chloride-ethylene copolymers, vinyl chloride-acrylic compound copolymers and vinyl chloride-ethylene-vinyl acetate copolymers.

Since the above are cited by way of example, other similar polymers can be used as well. Preferably, the chlorine-containing polymer used in the present invention is dissolved or dispersed in water or an organic solvent, such as alcohols such as isopropyl alcohol, ketones such as methylethyl ketone, esters such as ethyl cellosolve and hexane and toluene and Same hydrocarbons.

In the present invention, the qualitative weight of the chlorine-containing polymer is preferably 5,000 to 500,000, more preferably 10,000 to 200,000. If the molecular weight is less than 5,000, the mechanical strength of the coating layer will be insufficient. If the molecular weight exceeds 500,000, the film forming property of the coating liquid is impaired.

The chlorine content in the chlorine-containing polymer is preferably 10 to 75% by weight, more preferably 20 to 70% by weight. If the content of chlorine atoms in the chlorine-containing polymer is less than 10% by weight, good adhesion between the ultraviolet or electron beam curing layer and the base polyester film is not obtained. In the present invention, the chlorine-containing polymer is dissolved or dispersed in water or an organic solvent to prepare a coating liquid, which is applied onto a polyester film.

The concentration of the chlorine-containing polymer in the coating liquid is determined by various factors such as the coating method, the desired thickness of the coating layer, the mixing ratio and the like, but is usually in the range of 1 to 50% by weight. The content (after drying) of the chlorine-containing polymer in the coating layer is preferably at least 30% by weight. If this content is less than 30% by weight, inferior adhesion is caused.

Methylolated or alkylolated urea, melamine, guanimine, acrylamide or polyamide, epoxy compounds, aziridine compounds, blocked polyisocyanates, to improve the adhesion (blocking), water resistance, solvent resistance and mechanical strength of the coating layer, Silane coupling agents, titanium coupling agents, zirco-aluminate coupling agents, heat-, peroxide- or photoreactive vinyl compounds, photosensitive resins and the like can be contained in the present coating liquid as crosslinking agents. The amount of crosslinking agent in this coating liquid is usually 30 Joule%. If this content exceeds 30% by weight, there may be a problem that the crosslinking reaction does not proceed or the adhesiveness is insufficient. In addition, silica, silica sol, alumina, alumina sol, zirconium sol, kaolin, talc, calcium carbonate, titanium oxide, barium salt, carbon black, molybdenum sulfide, antimony oxide sol, etc. The particles may be contained in the coating layer in an amount of up to 50% by weight. In addition, if necessary, the coating liquid may be a defoamer, an applicability improving agent, a thickener, an antistatic agent, an organic lubricant, an oil-fat polymer particle, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, a pigment, and the like within the range of not affecting the effect of the present invention. It may contain from. This coating liquid may also contain other polymers in addition to the chlorine-containing polymers described above in order to improve the mechanical strength of the coating layer, the adhesion to the base polyester film or the adhesion.

The content of the polymer in the coating liquid is 70% by weight or less. Preferred examples of such other polymers are polyesters, polyurethanes and reactants of polyesters or polyurethanes with polymeric compounds having carbon-carbon unsaturated bonds.

Various methods of applying the above-mentioned coating liquid to form a coating layer of polyester on the film are described below. Wye, Harasakizer, Makishten, published in 1979, applied to unstretched polyester film using a reverse roll applicator, gravure applicator, rod applicator, air doctor applicator or other applicator as indicated in “Coating Method” A method of applying a liquid and biaxially stretching the applied film sequentially or simultaneously; A method of applying a coating liquid to a uniaxially stretched polyester film and stretching the film in a direction perpendicular to the first uniaxial stretching direction; One of the above-mentioned methods is a method of re-stretching a film in the longitudinal direction and / or the transverse direction with the biaxially stretched polyester which has the application layer obtained according to one; And a method of applying the coating liquid onto a biaxially stretched polyester film and then redrawing in the longitudinal and / or transverse directions.

The above stretching process is preferably carried out at a temperature of 60 to 130 ℃. The draw ratio is 6 to 6 times each in the longitudinal direction and the transverse direction and at least 4 times or more, preferably 6 to 20 times the area magnification. The stretched film is heat treated at 150 to 250 ° C.

It is preferable to relax this treated film 0.2 to 20% in the longitudinal and transverse directions in the heat treatment peak temperature zone and / or heat treatment cooling zone.

A particularly preferred method of the present invention is to apply the coating liquid to a uniaxially stretched polyester film drawn 2 to 6 times by the roll stretching method at 60 to 130 ° C., and then to perform the initial stretching without proper drying or drying. It is preferable to stretch 2 to 6 times at 80 to 130 ° C. in the direction perpendicular to the direction, to stretch the film 4 to 30 times at an area magnification, and to perform heat treatment at 150 to 250 ° C. for 1 to 600 seconds.

Redrawing the film in the longitudinal and / or transverse directions is carried out at a temperature of 105 to 150 ° C. and the film is stretched 1.01 to 2.0 times in the longitudinal and / or transverse directions. The heat treatment of the redrawn film is preferably performed for 0.1 to 600 seconds at a temperature of 190 to 250 ° C.

According to the present invention, the coating layer can be dried at the same time as it is stretched, and the thickness of the coating layer can be made thinner according to the stretching ratio, so that the substrate polyester suitable for various applications can be produced at a relatively low cost.

In the present invention, the coating liquid may be applied to one side or both sides of the polyester film. When the coating liquid of this invention is apply | coated on the surface of a polyester film, the other side of a film forms a coating layer using the coating liquid different from this invention, and adds the laminated polyester of this invention to a film Can impart enemy characteristics. In order to improve the applicability of the coating liquid to the film and the adhesiveness of the coating layer, the film may be subjected to chemical treatment or discharge treatment. Moreover, in order to improve the adhesiveness to the application layer of a biaxially-stretched polyester film, you may discharge-process after application | coating.

In the polyester film having the coating layer of the present invention obtained in the manner described above, the thickness of the base polyester film is preferably in the range of 3 to 500 µm, and the thickness of the coating layer is preferably 0.01 to 5 µm, more preferably. Preferably in the range of 0.02 to 1 μm. If the thickness of the coating layer is less than 0.01 µm, it is difficult to obtain a uniform coating layer. When the thickness of the coating layer exceeds 5 µm, the slipperiness of the film decreases, and the film handling becomes difficult.

The layer cured by irradiating ultraviolet rays or electron beams according to the present invention is, for example, the layer described in "UV.EB Curing Technology" issued in October 1982 by the General Technology Center. The cured layer is formed as follows. A photopolymerizable compound, such as a photopolymerizable monomer and a photopolymerizable prepolymer, a photopolymerization initiator and a photosensitizer-based composition are blended with dyes, pigments, polymers, inorganic compounds, magnetic particles, and the like, depending on the use of the product. Printing and application are carried out by a coating body such as a screen printing machine, offset printing machine, gravure printing, or the like, using itself as a solvent or using water or a conventional organic solvent as necessary. Subsequently, the solvent is removed and UV or electron beam irradiation is used to initiate the photopolymerization reaction to form a photopolymerizable compound as a crosslinked polymer, if necessary. The thickness of the cured layer depends on the type of layer but is usually in the range of 0.1 to 10 mu m.

The layer cured with ultraviolet rays or electron beams gives the following properties;

(1) Print and display of letters and figures on labels and magnetic cards,

(2) formation of insulating layers in wiring boards, etc .;

(3) Surface hardening with window stickers, membrane switches, etc.

(4) formation of a magnetic layer in a magnetic recording medium,

(5) transferability in electronic blackboard,

(6) Heat resistance and slip resistance in the backside treatment of thermal transfer.

The invention is described in detail with reference to the following non-limiting examples. Composition of Coating Liquid

Coating liquid A

Graffiti a mixture of a water dispersion of copolymer (I) consisting of 90 mol% vinylladen chloride, 8.5 mol% methyl acrylate and 1.5 mol% acrylic acid, 46.5 mol% methacrylic acid, 50.5 mol% butyl acrylate and 3.0 mol% acrylic acid. Aqueous dispersion of vinylidene chloride copolymer obtained by weight ratio (weight ratio copolymer (I) / mixture = 90/10)

The coating solution A is a water-dispersible poly-vinyl chloride having 65 parts by weight of the vinylidene chloride copolymer thus obtained (unless otherwise specified, solid parts by weight, the same as below), and 7.5 mol% of the sodium sulfoisophthalate component in the dicarboxylic acid component. It is prepared by dispersing 20 parts of ester, 10 parts of alkylolmelamine and 5 parts of inorganic particles.

Coating liquid B

65 parts of the water dispersion of the vinylidene chloride copolymer used in the coating solution A, 25 parts of the reaction product of the water dispersible polyester having 8.5 mol% of the sodium sulfoisophthalate component in the dicarboxylic acid component and the acrylic compound having an epoxy group and alkylol Aqueous dispersion of 10 parts melamine.

Coating liquid C

65 parts of aqueous dispersion of vinylidene chloride copolymer used in coating solution A, 20 parts of reaction product of water dispersible polyester and acrylic compound used in coating solution B, DICKFINE EN-002L (trade name, Dai Nippon as high molecular weight epoxy) An aqueous dispersion of 10 parts of Ink Chemical Industries Co., Ltd. and 5 parts of inorganic particles.

Coating liquid D

80 parts of NEOPRENE 750 (trade name, water dispersible chlorostyrene resin, Showa Neoprene Co., Ltd.), water-dispersible polyester ester of 8 mole% of naturm sulfoisophthalate component of dicarboxylic acid component and methyl methacrylate An aqueous dispersion comprising 19.5 parts of a copolymer of (water dispersible polyester / methyl methacrylate = 85% by weight / 15% by weight) and 0.5 part of lithium perfluoroalkylbenzenesulfonate.

Example 1

Polyethylene terephthalate having an intrinsic viscosity of 0.65 was melt extruded at 280 to 300 ° C. and cast on a cooling drum using an electrostatic bonding method to obtain an amorphous sheet having a thickness of 1360 μm. After the sheet was stretched 3.2 times in the longitudinal direction by the roll stretching method at 90 ° C., the coating liquid A was applied to both surfaces of the film. The coated film was stretched 3.3 times in the transverse direction at 110 ° C. and heat-treated at 210 ° C. to obtain a biaxially stretched polyester film having a thickness of 0.12 μm of the coating layer and 125 μm of the base film.

The coated polyester film thus obtained was cut and superimposed and dimensionally stabilized in an oven at 130 ° C.

In the screen printing machine, after forming the wiring circuit with silver paste and conducting ink on one side of the coating layer, the coating agent of 50 parts of ML 25089 and 450 SS 50 parts (UV curing type insulating material manufactured by Nippon Arch Corporation) is screened thereon. Apply to the front with a printing press. The coating agent was cured under UV irradiation conditions at a line speed of 2 m / min and 120 w / cm 2 to prepare a laminated polyester film having an insulating layer thickness of 90 μm.

The laminated polyester film was loaded with a direct current voltage of 10 V for 500 hours at 60 ° C. and 90% RH, and the state of the film was examined. Peeling of the insulating layer did not occur from the base of the laminated film. In addition, no deterioration of the electrical resistance of the circuit or silver migration was found.

Comparative Example 1

A laminated polyester film was produced in the same manner as in Example 1 except that the coating solution A was not applied. When the film was subjected to the same test treatment as in Example 1 at 60 ° C. and 90% RH atmosphere, peeling between the insulating layer and the substrate partially occurred and silver migration was found for 200 hours.

Example 2

Polyethylene terephthalate containing 14% by weight of titanium oxide was melt extruded at 280 to 300 ° C. and cast on a cooling drum using an electrostatic bonding method to prepare a 2100 μm thick amorphous sheet. This sheet was stretched 2.9 times in the longitudinal direction at 90 ° C. and coating liquid B was applied to both sides of this film. The film was further stretched 2.9 times at 110 ° C. and then heat-treated at 215 ° C. to obtain a biaxially stretched polyester film having a thickness of 0.15 μm and a base film thickness of 250 μm. The thermosetting magnetic paint was applied to one surface of the obtained polyester film, and then the magnetic paint was oriented and aged. On the non-magnetic coating layer of the film, UV-curable offset ink FD O-INDIGO-G (trade name, manufactured by Toyo Ink Menu Company Limited) was subjected to solid printing with an offset press, followed by a line speed of 10 m / The hardening process was carried out by ultraviolet irradiation of 160 W / cm <2> minutes, and the red-collar polyester film whose printed layer thickness is 5 micrometers was obtained.

The adhesion between the ultraviolet curing ink layer and the base polyester film of this laminated film was excellent; In the peeling test with a cellophane tape and the Hayden scratch tester (product zero) nail nail scratch test, the ink layer peeling did not arise from the base film. Therefore, this laminated film was useful for magnetic cards.

Comparative Example 2

A laminated polyester film was produced in the same manner as in Example 2 except that the coating solution B was not applied. The adhesiveness between the ink layer of the laminated polyester film and the base film was poor because the ink layer peeled from the base film over the entire surface in a bar test with a cellophane tape.

Example 3

In the same manner as in Example 2, a biaxially stretched polyester film having a coating layer thickness of 0.1 μm and a base film thickness of 188 μm formed by applying the coating solution B was obtained.

On one side of the obtained biaxially stretched polyester film, a magnetic layer and a heat-sensitive layer were formed by a stripe applicator, and printing was carried out in the same manner as in Example 2 on the margin and the opposite side of the film to obtain a laminated polyester film.

The adhesiveness between the ultraviolet curing ink layer and the base polyester film of the obtained laminated film was excellent.

Therefore, this laminated polyester film was useful as a magnetic card.

Example 4

Polyethylene terephthalate having an intrinsic viscosity of 0.63 and containing titanium oxide as added particles was melt extruded at 280 to 300 ° C. and cast on a cooling drum using an electrostatic bonding method to obtain an 820 μm thick amorphous sheet. The sheet was stretched 3.3 times in the longitudinal direction at 95 ° C. and then coating liquid C was applied to both sides of the longitudinally stretched film. This coated film was stretched 3.3 times at 110 ° C. and heat-treated at 210 ° C. to obtain a biaxially stretched polyester film having a thickness of 0.05 μm of the coating layer and a thickness of 75 μm of the base film.

On both sides of the obtained biaxially stretched polyester film, 70.0 g of γ-Fe ₂ O ₃ , 8.4 g of urethane acrylate composed of this phophorone diisocyanate, carrolactone polyol and 2-hydroxyethyl acrylate, tetraethylene glycol di A gravure applicator is coated with a gravure applicator, which is composed of 2.8 g of acrylate, 5.6 g of polyurethane, 3.0 g of vinyl chloride vinyl acetate copolymer, 0.8 g of lecithin, 2.0 g of carbon, and 190 g of methyl ethyl ketone. magnetic field orientation while drying the solvent, methyl ethyl ketone, and irradiated with an electron beam of 10 Mrad with an energy curtain EC-1 (trade name) of Energy Science Indus Tris to form a magnetic layer having a thickness of 5 탆.

The adhesiveness between the magnetic layer of this lamination and the base polyester film was excellent. In the coin scratch test, the magnetic layer showed cohesive failure and no interfacial delamination.

This laminated film was evaluated with a magnetic disk. In the endurance test to observe the presence or absence of peeling of the magnetic layer of the magnetic disk set in the disk drive device in which the 100 g load was applied in addition to the load of the magnetic head, the magnetic disk exhibited durability of 100 minutes or more and the adhesion between the magnetic layer and the base film was excellent. It was.

Comparative Example 3

A laminated polyester film having a magnetic layer was produced in the same manner as in Example 4 except that the coating solution C was not applied. In the scratch test by a coin, there existed the interface peeling between the magnetic layer of a laminated | multilayer, and a base film. In the endurance test by the magnetic disk drive, the endurance was 10 minutes or less.

Example 5

On the one side of the biaxially stretched polyester film having the coating layer by the coating liquid A obtained in Example 1, the urethane acrylate cutlery UNIDIC 17-806 (trade name, scratch resistant paints manufactured by Dai Nippon Ink Chemical Industries, Ltd.) UV curable resin) was applied with a bar coating key. The resin coating layer was dried at 80C for 2 minutes and subjected to ultraviolet irradiation at a line speed of 5 M / min and 100 W / cm ² to obtain a laminated polyester film having a cured layer thickness of 5 µm.

The adhesiveness between the cured layer of the obtained laminate and the base film was excellent because it was not peeled off in the peel test by cellophane tape. This hardened layer had a pencil hardness of 7H and high resistance even when rubbed at # 0000 steel ratio.

That is, this laminated film was useful as a surface hardening film.

[Comparative Example 4]

A laminated polyester film was produced in the same manner as in Example 5 except that the coating liquid A was not applied. Peeling between the cured layer and the base film occurred in the peeling test with the cellophane tape of this laminated polyester film, which was poor as a surface cured film.

Example 6

Polyethylene terephthalate having an intrinsic degree of 0.65 was melt extruded at 280 to 300 ° C. and cast on a cooling drum using electrostatic bonding to yield a 610 μm thick amorphous sheet. This sheet was stretched 3.5 times in the longitudinal direction at 95 ° C. and then coating liquid D was applied to one side of the obtained film. The film was stretched 3.5 times in the transverse direction at 108 ° C. and heat treated at 210 ° C. to obtain a biaxially stretched polyester film having a coating layer thickness of 0.12 μm and a base film of 50 μm.

Ultraviolet curing silkscreen printing ink FD SS 21-611 white (trade name), FD SS 21-152 red (trade name), FD SS 21-391 (trade name) Les FD SS 21-911 black (trade name) on the coating layer of the obtained film. (Toyo Ink, Inc., manufactured by Toyo Kogyo Co., Ltd.) was completely printed on a silk printing machine, and the laminated polyester film having an ink layer having a thickness of 10 μm was subjected to ultraviolet irradiation treatment at a line speed of 5 m / min 120 W / cm ² . Obtained.

The adhesiveness between the ink layer and the anchor film of the obtained laminated polyester film was excellent because the magnetic layer did not peel off from the base film in the peeling test with the cellophane tape. Therefore, this laminated polyester film was useful for display purposes, such as a label.

[Comparative Example 5]

A printed layer was formed according to Example 6 on the uncoated side of the biaxially stretched polyester film obtained in Example 6. The adhesion between the ink layer of the biaxially stretched polyester film and the base film was poor in the ink layer entirely from the dripping film in the peel test by cellophane tape.

Claims (4)

A laminated polyester film comprising a coating layer mainly composed of a chlorine-containing polymer formed on at least one surface of a biaxially oriented polyester film and a biaxially oriented polyester film, and an ultraviolet ray or electron beam cured layer formed on the coating layer. The homopolymer or copolymer of a chlorine compound having an active double bond, the copolymer of the chlorine compound and an olefin compound, a vinyl compound or an acrylic compound, the chlorine compound having an active double bond according to claim 1 And a chlorine and a polymer obtained by reacting a copolymer prepared by grafting a resin with a ethylene-vinyl acetate copolymer and chlorine with polyethylene, polypropylene or polyvinyl chloride and α-olefin. The chlorine-containing polymer according to claim 2, wherein the chlorine-containing polymer is a vinyl chloride homopolymer and copolymer, a vinylidene chloride homopolymer and copolymer, a chloroprene homopolymer and copolymer, a vinyl chloride and at least one vinyl acetate, an acrylic compound and an olefin compound. Laminated polyester film that is a homopolymer. The laminated polyester film according to claim 1, wherein the chlorine content in the chlorine-containing polymer is 10 to 75% by weight.