JPH0468334B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polyester film whose charging properties are improved by a coating layer.

[Conventional technology]

Biaxially oriented polyester films, especially biaxially oriented polyethylene terephthalate films, have excellent transparency, dimensional stability, mechanical properties, electrical properties, gas barrier properties, heat resistance, chemical resistance, etc., and are used as packaging materials and electrical insulation materials. It is used as a base material for photosensitive materials, drafting materials, electrophotographic materials, magnetic recording materials, etc. that use silver salts, diazo compounds, photosensitive resins, etc. Recently, magnetic recording media have become more densely recorded,
As the capacitance of capacitors increases, polyester films used are increasingly required to be flat and have good sliding properties, that is, smoothness. The need for smooth films is for optical applications,
It is also increasing in many other applications such as electrophotographic applications.

Conventional methods for improving the slipperiness of polyester films include adding fine organic or inorganic particles (additive particle method), and precipitating transesterification catalyst residue during polyester polymerization (precipitated particle method). ), a method using a polymer blend, and a method using a polyester composition, such as a method using an organic lubricant. However, in the methods using these compositions, if one of the slipperiness and flatness is improved, the other is decreased, and the reality is that it is difficult to improve both of them. Furthermore, methods using compositions may have limitations in optical applications that require transparency. The method of blending organic lubricants can achieve a certain degree of smoothness by appropriately combining inorganic particles, but it is difficult to contaminate equipment or products due to lubricant transfer, and to achieve a high degree of vacuum during the vapor deposition process. and maintenance difficulties,
There are many problems such as a decrease in adhesion between layers when formed into a laminate. There is a method to achieve smoothness by laminating a layer containing the composition with a flat layer by co-extrusion, but in addition to the above-mentioned problems with the composition, there are also problems such as shape transfer of the containing composition to the flat layer. There is. There is also a method of forming protrusions on the surface by stretching a film that has been surface-treated by solvent treatment, corona discharge treatment, etc., but there are various restrictions on the shape of the protrusions, and the slipperiness is often insufficient. In contrast to these methods, a method of forming fine and dense protrusions on the coating layer is attracting attention as a method for smoothing the film. As a method for forming protrusions in the coating layer, the method of incorporating fine inorganic particles is widely used to improve slipperiness and adhesion (blocking properties). A method of using a compound with characteristics of phase separation in the coating layer and elongation characteristics during coating and stretching as a coating agent for the stretching method (hereinafter referred to as coating and stretching) is attracting attention as a new method for producing smooth films. ing. For example, in JP-A-54-43017, gelatin is blended with polyester as a coating agent, and a polyester film with good slip properties is obtained by coating and stretching. After that, JP-A-1986
-10455 Publication, JP-A-57-18254, JP-A-Sho
A smooth film produced by coating and stretching has been proposed in Japanese Patent No. 58-62826 and the like. These are made by applying a coating agent to a film that has been stretched uniaxially in the longitudinal direction, and then stretching it in the transverse direction.The protrusion shape of the coating layer is long in the vertical direction, so the protrusion shapes are called "worm-like protrusions" and "mountain-like protrusions". (hereinafter abbreviated as vertical protrusion). Furthermore, as a special type of vertically long protrusions, ``discontinuous film-like protrusions'' in which the surface of the base polyester film is exposed due to breakage of the coating layer have also been proposed.

The present inventors previously proposed a smooth film by a coating and stretching method using a coating agent consisting of acrylic resin, polyester, specific water-soluble resin, or these and silica sol.
(Japanese Patent Application No. 1982-170929, Special Application No. 1982-170930).

The specific water-soluble resin is a resin that forms longitudinal protrusions by coating and stretching, and specifically includes gelatin, cellulose derivatives, and the like. However, although a smooth film can be obtained by the coating/stretching method, when increasing the film winding length on an industrial scale or unwinding the film at high speed, the flattening of the film causes an increase in the contact area. Problems such as the generation of sparks from the film due to the peeling charge when the film is unwound, which is presumed to be the case, and breakage due to the film being charged in close contact with each other may occur.

[Purpose of the invention]

An object of the present invention is to improve the charging properties of polyester films, particularly the peeling charging properties that tend to occur when an ultra-flat film is smoothed by a coating layer.

[Structure of the invention]

The present inventors investigated the composition of the coating layer and focused on a phthalocyanine metal complex that has photoconductivity. The inventors have discovered the basic effect of improving chargeability, and have arrived at the present invention.

That is, the present invention provides a phthalocyanine metal complex having a sulfonic acid group and/or a sulfonic acid group on at least one side of a polyester film.
It is a biaxially oriented polyester film having a coating layer consisting of 1% to 1% by weight and a water-soluble and/or water-dispersible resin.

As the polyester film constituting the substrate in the present invention, a polyethylene terephthalate film in which 80 mol% or more of its constituent components is ethylene terephthalate, or a polyethylene naphthalate film in which 80 mol% or more of its constituent components are ethylene naphthalate is used. Examples of polyester copolymerization components other than ethylene terephthalate and ethylene naphthalate include diethylene glycol, propylene glycol, neopentyl glycol,
1,4-butylene glycol, 1,4-cyclohexanedimethanol, polyethylene glycol,
Diol components such as polytetramethylene glycol, dicarboxylic acid components such as isophthalic acid, 5-sodiosulfoisophthalic acid, adipic acid, sebacic acid and their ester-forming derivatives, and oxycarboxylic acids such as oxybenzoic acid and its ester-forming derivatives. Acids can be used, but are not limited to these.

The polyester constituting the substrate in the present invention includes additive particles that form protrusions on the surface of the film.
The precipitated particles may contain a polyester having different properties from the base polyester or other resin. It is preferable to minimize these amounts in applications such as high-density magnetic recording applications in which a magnetic layer is made of vapor-deposited metal, but depending on the application, they may be contained in amounts conventionally used by those skilled in the art. Components other than the protrusion-forming agent may include an antistatic agent, a stabilizer, a lubricant, a coloring agent, a light blocking agent, etc., if necessary.

The phthalocyanine metal complex of the phthalocyanine metal complex having a sulfonic acid and/or sulfonic acid group in the present invention refers to the phthalocyanine metal complex having a sulfonic acid and/or a sulfonic acid group, "Photochemistry", No. 7,
As described on page 30 (1983), Cu, Co, Fe,
Refers to complexes of Ni, Pb, trivalent metals such as Al, Ga, Cr, and tetravalent metals such as Si, Sn, Ge, etc. The phthalocyanine metal complex in the present invention has one complex in the aromatic nucleus of phthalocyanine. The above-mentioned sulfonic acid group or sulfonic acid group (the salt-forming cation is an alkali metal, an alkaline earth metal, or ammonium (including substituted ammonium)) is introduced. The sulfonic acid group or sulfonic acid group has the effect of making the phthalocyanine metal complex water-soluble or water-dispersible so that it can be used as a water-based coating agent, and also improving the charging property when moisture is absorbed. In addition, the aromatic nucleus of the phthalocyanine metal complex in the present invention may have a substituent such as a halogen, a nitro group, or an alkyl group in addition to the sulfonic acid group or the sulfonic acid group. The content of the phthalocyanine metal complex in the coating layer in the present invention is:
1% to 80% by weight, more preferably 3% by weight
~60% by weight. If the content of the phthalocyanine metal complex in the coating layer is less than 1% by weight, the effect of improving charging properties is insufficient, and if it is more than 80% by weight, the strength of the coating layer decreases. The phthalocyanine metal complex of the present invention has a low vapor pressure and exhibits conductivity upon activation by light even without moisture absorption, and is particularly suitable for processing films in a vacuum system.

The water-soluble or water-dispersible resin in the present invention functions as a so-called binder that mutually binds sulfonic acid groups and/or phthalocyanine metal complexes having sulfonic acid groups, and also binds the coating layer and the polyester of the base. Examples of water-soluble or water-dispersible resins include polyester, polyamide, polyurethane, acrylic resin, polyolefin, vinyl resin, butadiene resin,
Epoxy resin, silicone resin, fluorine resin,
At least one or more of cellulose resins, polyethers, gelatin, etc. can be used, but the material is not limited thereto. These resins may be used depending on the application; for example, polyurethane is preferred for applications requiring adhesiveness to various topcoats, and acrylic resins are preferred for applications where slipperiness is important. Furthermore, if the coating stretching method is performed using a coating agent containing gelatin, cellulose resin, polyacrylate, polystyrene, etc. among these resins, vertical protrusions will be formed in the coating layer, which will cause the film to deteriorate. The slipperiness of the material can be improved.

The method for applying coating agent to polyester film is to use a reverse roll coater as shown in ``Coating Method'' by Yuji Harasaki, published by Maki Shoten in 1979.
A gravure coater, a rod coater, an air doctor coater, or a coating device other than these can be used. The coating may be applied to the biaxially stretched polyester film before sequential biaxial stretching, before simultaneous biaxial stretching, after biaxial stretching and before restretching, or after commercialization. It is preferable to use a method (coating/stretching method) in which a coating agent is applied to a polyester film, followed by appropriate drying or stretching without drying. In addition, an aqueous dispersion or aqueous solution of a coating agent is applied to a uniaxially stretched polyester film by the roll stretching method, and the polyester uniaxially stretched film is immediately stretched in a direction perpendicular to the previous stretching direction, and then dried appropriately or without drying. Particularly preferred is stretching and heat treatment. According to this method, the coating layer can be dried simultaneously with stretching, and the thickness of the coating layer can be reduced in accordance with the stretching ratio. In addition, in the case of films containing inorganic particles in the coating layer for the purpose of improving slipperiness, the protrusions caused by the inorganic particles in the coating layer produced by the coating and stretching method become steeper, resulting in better slipperiness compared to films that are not coated and stretched. becomes. Furthermore, in order to form protrusions in a coating layer using an organic resin, a coating and stretching method is essential.

The thickness of the coating layer of the biaxially stretched polyester film of the present invention is preferably in the range of 0.01μ to 1μ, more preferably in the range of 0.01μ to 0.1μ. If the thickness of the coating layer is less than 0.01 μm, it will be difficult to apply it uniformly, resulting in uneven coating on the product, and if it is thicker than 1 μm, the slipperiness may actually decrease.

In the coating layer of the present invention, methylol- or alkylol-based urea, melamine, or guanamine-based crosslinking agents are used to improve the adhesion (blocking property), water resistance, solvent resistance, and mechanical strength of the coating layer. , acrylamide-based, polyamide-based compounds, epoxy compounds, aziridine compounds, blocked polyisocyanates, silane coupling agents,
It may contain a titanium coupling agent, a zirco-aluminate coupling agent, a vinyl compound or a photosensitive resin that is reactive with heat, peroxide, actinic radiation, etc. In addition, the coating layer of the present invention contains inorganic fine particles to improve adhesion and slipperiness.
Silica, silica sol, alumina, alumina sol,
It may contain zirconium sol, kaolin, talc, calcium carbonate, titanium oxide, barium salt, carbon black, molybdenum sulfide, antimony oxide sol, and the like. In addition, the coating layer of the present invention may optionally contain an antifoaming agent, a coating properties improver, a thickener, an antistatic agent, an organic lubricant, an organic polymer particle, an antioxidant, an ultraviolet absorber, a foaming agent, etc. agents, dyes,
It may also contain pigments and the like.

In order to improve the applicability and adhesion of the coating agent to the film, the film may be subjected to chemical treatment or electrical discharge treatment before coating.

In order to improve the adhesion, coating properties, etc. of the biaxially stretched polyester film of the present invention to the coating layer, the coating layer may be subjected to electrical discharge treatment after the coating layer is formed.

The biaxially stretched polyester film of the present invention is
It can be used as a 1μ to 500μ film.

Hereinafter, the present invention will be explained by giving examples. Note that the evaluation in the examples is based on the method described below.

(1) Workability Approximately 30 sheets of A4 size film are stacked, and the overall flexibility and
The peelability, pullability, and chargeability of each film were observed.

(2) Coefficient of Friction The coefficient of friction between films was measured according to ASTM-D-1894-63.

(3) Winding property When the film was wound into a roll, the presence or absence of so-called winding misalignment, step misalignment, wrinkles, bumps, dent marks, etc. was observed.

(4) Sticking property (blocking property) Heat press in a constant temperature and humidity chamber at 40℃, 80%RH,
ASTM-D of film layered at 10Kg/ ^cm2 for 20 hours
Peel strength was measured by the method of -1893.

(5) Surface roughness Measured with a thin film step meter ET-10 manufactured by Kosaka Laboratory with a stylus tip radius of 0.5 μ and a stylus load of 1 g, and the height from the base to the top of the protrusion was defined as the surface roughness. .

(6) Charging property The charging property when the film was wound into a roll was determined by observing whether the A4 size films adhered to each other due to static electricity as described in the workability section of the evaluation method.

Charge attenuation when forcibly charged is measured using Statistic Honest Meter S4104 manufactured by Shishido Shokai.
The film was charged with a discharge voltage of 10KV using a 10KV discharge voltage, and then measured at 23℃ and 50%RH. In addition, the film being measured under the above measurement conditions was heated at 35°C.
Charge attenuation was measured by blowing 100% RH air (forced humidification effect).

(7) Adhesion of the magnetic layer The adhesion of the magnetic layer was determined by coating the magnetic paint with a solid content of 5 μm on the coating layer of the biaxially stretched polyester film, drying it at 80℃ for 1 minute, and then drying it at 80℃ for 24 hours. Scotch tape with a width of 17.7 mm manufactured by Sumitomo 3M was applied to the surface of the aged magnetic layer, and a T-peel test was conducted using a tensile tester.

The composition of the magnetic paint is 50 parts of polyurethane, 20 parts of nitrocellulose, 3.0 parts of vinyl chloride-vinyl acetate resin, 7.5 parts of isocyanate compound, 12 parts of carbon black,
4 parts of lecithin and 460 parts of γ-Fe ₂ O ₃ were dispersed in 900 parts of a solvent containing equal amounts of methyl ethyl ketone, toluene, and methyl isobutyl ketone.

Comparative Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.62 and containing almost no surface protrusion forming agent based on polymerization catalyst residue etc. was melted at about 285°C and extruded onto a cooling drum at about 60°C while applying electrostatic charge. Further, the film was stretched 3.5 times in the machine direction at 83°C with rolls, then stretched in the transverse direction at 110°C, and heat treated at 220°C to obtain a biaxially stretched film with a thickness of 12.1μ and a surface roughness of 50Å. This film had extremely poor winding properties, making it difficult to obtain a long film roll, and the resulting film roll had a poor winding appearance, making it impossible to ship as a product. Just to be safe, I cut it out as an A4 size sheet and observed the workability, but the films stuck together and became one whole, making it difficult to handle the film. The coefficient of friction of this film could not be measured because the film did not slip. The chargeability was poor as no charge decay was observed even when the forcibly charged film was subjected to forced humidification. That is, this film had poor slip properties and charging properties, and could not be put to practical use.

Example 1 60 parts of Dyurimer AT-M918 (trade name), a water-soluble acrylic resin manufactured by Nippon Pure Chemical Industries, Ltd., and Polyester XWR-901 (trade name), a water-dispersible polyester manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd. name) 20 copies, Nissan Chemical Industries, Ltd.
Comparative Example 1 was prepared using a coating agent containing 5 parts of Snowtex 20L (trade name), a silica sol manufactured by Co., Ltd., and 15 parts of copper phthalocyanine, which has 1.8 sodium sulfonate groups per molecule, manufactured by Mitsubishi Chemical Industries, Ltd. It was coated on one side of the longitudinally stretched film, and then the same procedure as in Comparative Example 1 was carried out to obtain a biaxially stretched polyester film.
The amount of coating agent applied to this film is 0.04g/m ²
It was hot. This film had good winding properties and workability. The charging property was good, with charge attenuation due to forced humidification. The adhesion of this film is 12
g, static friction coefficient is 0.65, dynamic friction coefficient is 0.57,
The surface roughness was 150 Å.

In addition, Dyurimer AT-
A biaxially oriented polyester film obtained by similarly applying a coating agent containing 75 parts of M918, 20 parts of Polyester XWR901, and 5 parts of Snowtex 20L has relatively good winding and workability. The coefficient of static friction was 0.63, and the coefficient of dynamic friction was 0.58, indicating that the film was good in normal handling.However, depending on the winding conditions of the film or the handling conditions of the film user, the film may be detached and charged when unwinding. I found out that it is easy to occur. The surface roughness of this film was 120 Å, and there was no charge attenuation due to forced humidification after forced charging.

In other words, the biaxially oriented polyester film in this example, which has copper phthalocyanine having a sulfonic acid group in the coating layer, has good charging characteristics, so it is possible to have a wide range of winding conditions in the film manufacturing process, and it is easy for the user to use. Handling during film processing has also become easier.

Example 2 50 parts of Dyurimer AT-M918 (trade name), a water-soluble acrylic resin manufactured by Nippon Pure Chemical Industries, Ltd., and Polyester XWR-901 (trade name), a water-dispersible polyester manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd. name) 20 copies, Nissan Chemical Industries, Ltd.
5 parts of Snowtex 20L (trade name), a silica sol manufactured by Mitsubishi Chemical Industries, Ltd., 15 parts of a compound containing 1.8 sodium sulfonate groups per molecule of phthalocyanine copper manufactured by Mitsubishi Chemical Industries, Ltd., and A film coated with a coating agent containing 10 parts of Marporose M-25, which is methyl cellulose, was obtained in the same manner as in Example 1. The windability and workability of this film were good, the adhesion was 9 g, the coefficient of static friction was 0.60, the coefficient of dynamic friction was 0.56, the surface roughness was 200 Å, and the charge decay due to forced humidification after forced charging was good. . Note that the surface shape of the coating layer of this film formed vertically long protrusions due to the blending of methylcellulose.

Example 3 When a biaxially stretched polyethylene terephthalate film with a thickness of 15 μm was made using the same method as in the comparative example using particles on which a polyester production catalyst was precipitated and inorganic particles added externally during the polyester production process, the surface roughness was 500 Å. , using polyethylene terephthalate with an intrinsic viscosity of 0.65 and a coefficient of static friction of 0.37 and a coefficient of dynamic friction of 0.35, 70 parts of Jyurimer AT-M918 Improved 4 (trade name), a water-soluble acrylic resin from Nippon Pure Chemical Industries, Ltd., and Nippon Gosei Co., Ltd. Contains 20 parts of POLYESTER and Inplanil DLH, a water-dispersible polyurethane manufactured by Bayer AG.
70 parts of (trade name), Finetex ES, a water-dispersible polyester manufactured by Dainippon Ink and Chemicals Co., Ltd.
A coating agent containing 20 parts of -670 (trade name) and 10 parts of copper phthalocyanine containing 1.8 sodium sulfonate groups per molecule manufactured by Mitsubishi Chemical Industries, Ltd. was applied to one side in the same manner as in Example 1. A biaxially stretched polyethylene terephthalate film with a thickness of 15 μm was obtained. These films had no problems in winding and workability. These films were forcibly charged and the charge attenuation due to forced humidification was evaluated and found to be good. These films had extremely reduced adsorption of fine polyethylene terephthalate powder, polyethylene terephthalate oligomers, dust in the air, etc. that would be seen when electrostatically charged. The magnetic layer adhesion is
The weight of the film having a coating layer mainly composed of acrylic resin was 127g, and the weight of the film having a coating layer mainly composed of polyurethane was 144g.

That is, the biaxially stretched polyester film of this example was useful as a magnetic recording medium because it prevented the adhesion of fine powder and the like that would deteriorate the magnetic properties due to the improved charging property.

Example 4 Using the same polyethylene terephthalate raw material as in Example 1, 65% of Jyurimer AT-M918 Improved 4 (trade name), a water-soluble acrylic resin from Nippon Pure Chemical Industries, Ltd.
20 parts of water-dispersible polyester Polyester A coating agent containing 10 parts of a phthalocyanine copper compound containing 1.8 sodium sulfonate groups per molecule was applied to both sides of the film after longitudinal stretching, and the coating amount was 0.04 g/m ² in the same manner as in Example 1. A biaxially stretched polyester film having a film thickness of 75 μm was obtained. Compared to a film without a coating layer, this film had good winding properties, workability, charging properties, and magnetic layer adhesion.

That is, even a thick, stiff, and ultra-flat 75μ film can be easily handled by forming the coating layer of the present invention, and is useful for floppy disk applications.

〔Effect of the invention〕

As shown in the above examples, the biaxially stretched polyester film of the present invention has good charging properties and is useful as a base material for packaging materials, graphic materials, electrophotographic materials, magnetic recording materials, and the like.

Claims (1)

[Claims] 1. A biaxially oriented polyester film having a coating layer containing 80% by weight to 1% by weight of a phthalocyanine metal complex having a sulfonic acid group and/or a sulfonic acid group and a water-soluble and/or water-dispersible resin on at least one side of the polyester film. .