JP2016138207A - Coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antistatic film excellent in conductivity, water resistance, solvent resistance, transparency and atmosphere exposure resistance efficiently at low cost.SOLUTION: There is provided a coating film having an antistatic coated layer formed from a coating liquid containing following compounds (A), (B) and (C) on at least single side face of a polyester film. (A) a polymer doped by other anionic compounds to a compound consisting of thiophene or a thiophene derivative or a polymer self doped having an anionic group in the compound consisting of thiophene or a thiophene derivative. (B) one or more kind of compound selected from a group of glycerol (b1), polyglycerol (b2), an alkylene oxide addition article to glycerol or polyglycerol (b3) and polyalkylene oxide (b4). (C):a polyester resin.SELECTED DRAWING: None

Description

  The present invention relates to an antistatic film, and more particularly, to an antistatic film having excellent conductivity, water resistance, solvent resistance, transparency and high productivity under low humidity, and a flat The present invention relates to an antistatic film suitable for use in panel displays, touch panel peripheral members, release films, thermal ribbons, image receiving papers, printing plates, carrier tapes, trays, magazines, semiconductor element packaging and the like.

  Polyester films represented by polyethylene terephthalate or polyethylene naphthalate are superior in mechanical strength, dimensional stability, flatness, heat resistance, chemical resistance, optical properties, etc., and cost performance. Although it is used as a material, the polyester film is easily charged during friction, peeling of the adhesive layer, and the like, causing problems such as adhesion of foreign matter and dust, and electrostatic discharge failure.

  For this reason, various measures for preventing charging have been taken. Among them, a general method is to apply an antistatic resin to the surface.

  Examples of the antistatic agent applied to the polyester film include a cationic compound containing a cationic group represented by a quaternary ammonium group, an anionic group containing an anionic group represented by a sulfonate group and a phosphonate group. Compounds are mainly used. These are ionic conductive and antistatic ability is easily affected by surrounding moisture and moisture. In particular, there is a drawback in that the conductivity is lowered under low humidity and the desired antistatic ability cannot be obtained. This tendency is more pronounced in anionic antistatic agents.

  Also, in recent years, there is often a demand for non-halogenation in polyester films due to increased concern about environmental problems and concerns about the impact on other members incorporated together. In the case of a cationic system, a compound in which the counter anion of the quaternary ammonium group is a chloride ion is generally used, but in this case, it cannot be used. There are compounds in which the counter anion is a monoalkyl sulfate ion, an alkyl sulfonate ion or the like, but the ion mobility is low and the antistatic performance is poor.

  The electronically conductive compound can exhibit better antistatic properties than the above-described ionic conductive compound, and is hardly affected by humidity. As the electroconductive compounds, various conductive organic polymer compounds, among them, conductive polymer compounds such as polyacetylene, polyphenylene, polyaniline, polypyrrole, polyisothianaphthene, polythiophene have been proposed.

  Among these, the polythiophene compound has excellent electrical conductivity, and can exhibit high antistatic properties and transparency when applied to a film (Patent Documents 1 and 2).

  In the stretched polyester film, it is advantageous in terms of productivity and economy to provide a coating film by a so-called in-line coating method in which coating is performed during the film forming process (Patent Documents 3 and 4), but contains a polythiophene compound. If the coating layer is provided by this in-line coating method, it is difficult to develop sufficient antistatic performance.

  This is because when the electronic conductive layer is stretched along with the stretching of the film, the electronic conductive layer cannot follow the stretching of the film while maintaining the conductive mechanism, and as a result, the conductive mechanism is broken. Conceivable.

  Moreover, the coating layer in such a case is inferior in appearance, and application to an optical member becomes difficult. For this reason, there is a need for a method that exhibits excellent antistatic properties in the in-line coating method and has few appearance defects.

  Since the polythiophene compound is expensive and strongly colored, it is preferable to reduce the coating amount as much as possible. However, if the coating amount is decreased, the stability of the coating layer is impaired. Specifically, the conductivity deteriorates with time by exposing the coating layer to the atmosphere under the illuminance at the indoor light level (hereinafter referred to as atmospheric exposure). Another problem is that the stability (exposure resistance to air) is good while reducing the coating amount.

  Further, it is considered that the antistatic layer is often further coated with an adhesive, mold release, or other functional layer, and in this case, the solvent resistance of the antistatic layer becomes important. Patent Document 5 discloses a coating film having antistatic properties, transparency, solvent resistance, economy, and atmospheric exposure resistance. However, ketone-based and ester-based solvents often used for functional layer coating. It is not always sufficient in the solvent resistance against.

JP 2002-060736 A JP 2008-296380 A JP 2003-154594 A Japanese Patent Laid-Open No. 9-131843 JP 2014-173015 A

  The present invention has been made in view of the above-mentioned circumstances, and the problem to be solved has excellent antistatic properties and economical efficiency, and at the same time, transparency, resistance to atmospheric exposure, and solvent resistance to ketone-based and ester-based solvents. An object of the present invention is to provide a coated film having both properties.

  As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by providing a coating layer composed of a combination of specific types of compounds, and have completed the present invention. .

That is, the gist of the present invention is characterized by having an antistatic coating layer formed from a coating solution containing the following compounds (A), (B), and (C) on at least one surface of a polyester film. It exists in the coated film.
(A): A polymer obtained by doping a compound comprising thiophene or a thiophene derivative with another anionic compound, or a polymer having an anionic group in a compound comprising a thiophene or thiophene derivative and self-doped.
(B): One or more compounds (C) selected from the group of glycerin (b1), polyglycerin (b2), glycerin or alkylene oxide adduct (b3) to polyglycerin, and polyalkylene oxide (b4): Polyester resin

  According to the present invention, it is possible to provide a coated film having excellent antistatic properties and economy, and at the same time, having transparency, resistance to atmospheric exposure, and solvent resistance to ketone and ester solvents. The industrial value of the invention is high.

The base film of the coated film of the present invention is made of polyester. Such polyesters include dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, 4,4′-diphenyldicarboxylic acid, 1,4-cyclohexyldicarboxylic acid or esters thereof. It is a polyester produced by melt polycondensation with glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol. Polyesters composed of these acid components and glycol components can be produced by arbitrarily using a commonly used method.
For example, a transesterification reaction between a lower alkyl ester of an aromatic dicarboxylic acid and a glycol, or a direct esterification of an aromatic dicarboxylic acid and a glycol, to form a substantially bisglycol of an aromatic dicarboxylic acid A method is employed in which an ester or a low polymer thereof is formed and then polycondensed by heating under reduced pressure. Depending on the purpose, an aliphatic dicarboxylic acid may be copolymerized.

  Typical examples of the polyester of the present invention include polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and the like. It may be a polymerized polyester and may contain other components and additives as necessary.

  The polyester film in the present invention can contain particles for the purpose of ensuring the film runnability and preventing scratches.

  The particle size and content of the particles are selected according to the use and purpose of the film. The amount of particles in the case of inclusion is usually 0.0003 to 1.0% by weight with respect to the polyester, preferably 0.00. It is in the range of 0005 to 0.5% by weight. When the amount of contained particles exceeds 1.0% by weight, the transparency of the film may be insufficient. If the amount is small, the effect of the particles may not be sufficient.

  When there are no or few particles, the transparency of the film becomes high and a good film is obtained, but it may be difficult to handle such as insufficient slipping, so particles are put in knurling or coating layer etc. May need to be devised.

  The average particle size when particles are contained is usually in the range of 0.01 to 5 μm. If the average particle diameter exceeds 5 μm, the film surface roughness tends to be too rough, or the particles tend to fall off from the film surface. If the average particle size is less than 0.01 μm, the effect of the particles may not be sufficient.

  Examples of the particles to be included include inorganic substances such as silica, calcium carbonate, magnesium carbonate, calcium phosphate, kaolin, talc, aluminum oxide, titanium oxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, and molybdenum sulfide. It is possible to use particles, crosslinked polymer particles, organic particles such as calcium oxalate, and precipitated particles during the polyester production process.

  In addition, various stabilizers, lubricants, antistatic agents and the like can be appropriately added to the film.

  As a film forming method of the film of the present invention, a generally known film forming method can be adopted, and there is no particular limitation. For example, a sheet obtained by melt extrusion is first stretched 2 to 6 times at 70 to 145 ° C. by a roll stretching method to obtain a uniaxially stretched polyester film, and then perpendicular to the previous stretching direction in the tenter. A film is obtained by extending | stretching 2 to 6 times at 80-160 degreeC to the direction, and also heat-processing (heat setting) at 150-250 degreeC for 1 to 600 seconds. Further, at this time, a method of relaxing 0.1 to 20% in the longitudinal direction and / or the transverse direction in the heat treatment zone and / or the cooling zone at the heat treatment outlet is preferable.

  The polyester film in the present invention may have either a single layer or a multilayer structure. In the case of a multilayer structure, the surface layer and the inner layer, or both surface layers can be made of different polyesters depending on the purpose.

  The transparency of the polyester film in the present invention is not particularly limited, but when transparency is required, taking advantage of the fact that the coating layer of the present invention is transparent, the haze of the entire film is 3.0% or less, and further 1 It is preferable to make it 0.0% or less.

  The total light transmittance of the polyester film in the present invention is not particularly limited, but is preferably 80% or more, and more preferably 85% or more.

The antistatic coating layer in the present invention is specifically a coating layer having a mechanism in which the surface resistivity of the coating layer is low and charges are leaked. It can be said that the lower the surface resistivity of the coating layer, the better the antistatic property. If the surface resistivity is less than 1 × 10 ¹² Ω, it can be said to have antistatic properties, and if it is less than 1 × 10 ⁸ Ω, it can be said to have good antistatic properties, and if it is less than 1 × 10 ⁶ Ω. Very good antistatic performance is preferable.

The lower limit of the surface resistivity is not particularly limited, but is preferably 1 × 10 ⁴ Ω or more in consideration of the cost of the conductive agent.

  Next, the compounds (A), (B), and (C) used in the present invention will be described.

  The compound (A) is a polymer doped with a compound comprising thiophene or a thiophene derivative with another anionic compound, or a polymer doped with a ionic group in a compound comprising a thiophene or thiophene derivative. . These substances are preferable because of their excellent conductivity. Examples of the compound (A) include those obtained by polymerizing a compound of the following formula (1) or (2) in the presence of a polyanion.

In the above formula (1), R ¹ and R ² each independently represent hydrogen or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or the like.

  In said formula (2), n represents the integer of 1-4.

  Examples of the polyanion used at the time of polymerization include poly (meth) acrylic acid, polymaleic acid, polystyrene sulfonic acid, and polyvinyl sulfonic acid. As a method for producing such a polymer, for example, a method as disclosed in JP-A-7-90060 can be employed.

  In the present invention, a preferred embodiment includes a compound of the above formula (2) in which n is 2 and polystyrene sulfonic acid is used as a polyanion.

  Moreover, when these poly anions are acidic, some or all may be neutralized. As the base used for neutralization, ammonia, organic amines, and alkali metal hydroxides are preferable.

  The compound (B) is at least one compound selected from the group consisting of glycerin (b1), polyglycerin (b2), glycerin or an alkylene oxide adduct (b3) to polyglycerin, and a polyalkylene oxide (b4).

  Glycerin (b1) and polyglycerin (b2) are compounds represented by the following general formula (3).

  The compound in which n in the above formula is 1 is glycerin (b1), and the compound in which n is 2 or more is polyglycerin (b2). In this invention, n in a formula is 2-20 normally, Preferably it is 3-10, More preferably, it is the range of 4-6.

  The alkylene oxide adduct (b3) to glycerin or polyglycerin has a structure in which alkylene oxide is added and polymerized to the hydroxyl group of glycerin or polyglycerin represented by the general formula (3).

  Here, the structure of the alkylene oxide added may differ for every hydroxyl group of glycerol or polyglycerol skeleton. Moreover, it is sufficient that it is added to at least one hydroxyl group in the molecule, and it is not necessary that alkylene oxide or a derivative thereof is added to all hydroxyl groups.

  Preferable alkylene oxide added to glycerin or polyglycerin is ethylene oxide or propylene oxide. When the alkylene chain of the alkylene oxide becomes too long, the hydrophobicity becomes strong, the uniform dispersibility in the coating solution deteriorates, and the antistatic property and transparency of the antistatic coating layer tend to deteriorate. Particularly preferred is ethylene oxide. Further, the number of addition is preferably in the range of 200 to 2000 in terms of the number average molecular weight as the final compound (b3), more preferably in the range of 300 to 800.

  Preferable polyalkylene oxide (b4) is polyethylene oxide or polypropylene oxide. If the alkyl chain in the alkylene oxide structure becomes too long, the hydrophobicity becomes strong, the uniform dispersibility in the coating solution deteriorates, and the antistatic property and transparency of the antistatic coating layer tend to deteriorate. . Particularly preferred is polyethylene oxide. A number average molecular weight of 200 to 2000 is more preferred.

  In the present invention, particularly preferred embodiments of the compound (B) are polyglycerin (b2) and alkylene oxide adduct (b3) to glycerin or polyglycerin. Moreover, the mixed use of (b2) and (b3) is also preferable.

Compound (C) is a polyester resin.
The polyester resin (C) in the present invention includes, for example, those composed of the following polyvalent carboxylic acid and polyvalent hydroxy compound as main constituent components. That is, as the polyvalent carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6 -Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid monopotassium salt and ester-forming derivatives thereof can be used. As polyvalent hydroxy compounds, ethylene Recall, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol , Neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, Polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like can be used. One or more compounds may be appropriately selected from these compounds, and a polyester resin may be synthesized by a conventional polycondensation reaction.

  Of these, a product obtained by copolymerizing sulfoisophthalic acid as a part of the polyvalent carboxylic acid, introducing a sulfonic acid group into the polyester skeleton, neutralizing it, and making it hydrophilic as an ionomer is preferably used. The amount to be copolymerized is usually 1 to 10 mol%, preferably 1 to 5 mol%, more preferably 1 to 3 mol% based on the whole polyvalent carboxylic acid.

  In the present invention, the compounds (A), (B), and (C) do not have any particular obstacle in selecting compounds that do not contain a halogen atom. Therefore, in the present invention, it is easy and preferable that the antistatic layer contains no halogen.

The weight (nonvolatile content) of the compound (A) in the antistatic coating layer provided by the present invention is usually 0.3 to 15 mg / m ² , preferably 1 to 5 mg / m ² , more preferably 2 to ² mg / m ² . 3 mg / m ² . When the amount of the compound (A) is less than this, the antistatic property or the resistance to atmospheric exposure may be insufficient. On the other hand, if it is more than this, the cost increases, and the coloring tends to be strong. Moreover, when extending | stretching, problems, such as a transparency fall, may be caused.

  The ratio of the compound (A) (nonvolatile content) to the total nonvolatile content in the coating solution for forming the coating layer is usually 1 to 50%, preferably 2 to 30%, more preferably 3 to 15% by weight. Preferably it is 5 to 10%. If the ratio of the compound (A) is higher than this, the strength, transparency or antistatic performance of the coating film may be insufficient. When the ratio of the compound (A) is lower than this, the antistatic performance may be insufficient, or the coating film for imparting sufficient antistatic performance may be extremely thick. When the coating film is thick, it may be liable to deteriorate the appearance and transparency, block the film, and increase the cost.

  The ratio of the compound (B) (nonvolatile content) is usually 1 to 95% by weight, preferably 30 to 90%, more preferably 40 to 85%, and still more preferably 50 to 80%. Outside this range, the antistatic performance and the appearance of the coating film tend to deteriorate.

  The ratio of the compound (C) (nonvolatile content) is usually 1 to 90% by weight, preferably 3 to 50%, more preferably 5 to 40%, and still more preferably 10 to 30%. Outside this range, the antistatic performance and the strength and appearance of the coating film tend to deteriorate.

  The coating solution used in the present invention may contain a surfactant in order to improve the coating property to the film. As this surfactant, it is particularly preferable to use a nonionic compound containing (poly) alkylene oxide, (poly) glycerin, or a derivative thereof in the structure without impairing the conductivity of the resulting coating layer. Furthermore, the thing which has a fluoroalkyl group in a hydrophobic part is preferably used from a viewpoint of coating property.

  The coating solution used in the present invention may contain a crosslinking reactive compound as necessary. Crosslinking reactive compounds mainly improve the cohesiveness, surface hardness, scratch resistance, solvent resistance, and water resistance of the coating layer by crosslinking reactions with functional groups contained in other resins and compounds, or by self-crosslinking. be able to. As the crosslinking reactive compound that can be used, amino resins such as melamine, benzoguanamine, and urea, isocyanate, oxazoline, epoxy, and glyoxal are preferably used. Also included are polymer-type cross-linking reactive compounds having reactive groups in other polymer skeletons.

  Furthermore, you may use together 1 type, or 2 or more types of binder resins other than (C) as needed. Examples of such binder resins include polyether resins, polyurethane resins, acrylic resins, vinyl resins, epoxy resins, amide resins, and the like. In these, each skeleton structure may have a composite structure substantially by copolymerization or the like. Examples of the binder resin having a composite structure include acrylic resin graft polyester, acrylic resin graft polyurethane, vinyl resin graft polyester, and vinyl resin graft polyurethane. By containing these resins, there is a possibility that the strength of the resulting coating layer and the adhesion to the substrate film can be improved.

  The coating liquid used in the present invention includes an antifoaming agent, a coating property improver, a thickener, an organic lubricant, a release agent, organic particles, inorganic particles, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, You may contain additives, such as a pigment. These additives may be used alone or in combination of two or more as necessary. Further, as these additives, it is more preferable to use those containing (poly) alkylene oxide, (poly) glycerin, or derivatives thereof in the structure because the antistatic property of the resulting coating layer is difficult to inhibit.

  The coating liquid in the present invention is preferably an aqueous solution or a water dispersion from the viewpoint of handling, working environment, and stability of the coating liquid composition, but water is the main medium. An organic solvent may be contained as long as it does not exceed the range.

  Next, formation of the coating layer which comprises the laminated polyester film in this invention is demonstrated. Regarding the coating layer, it may be provided by in-line coating which treats the film surface during the process of forming a polyester film, or offline coating which is applied outside the system on a once produced film may be adopted. More preferably, it is formed by in-line coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film, and specifically, a method of coating at any stage from melt extrusion of a polyester to heat setting after stretching and winding up. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, and a film after heat setting and before winding. Although not limited to the following, for example, in sequential biaxial stretching, a method of stretching in the transverse direction after coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) is particularly excellent. According to such a method, film formation and coating layer formation can be performed at the same time, so there is an advantage in manufacturing cost. In addition, in order to perform stretching after coating, the thickness of the coating layer can be changed by the stretching ratio. Compared to offline coating, thin film coating can be performed more easily. Further, by providing the coating layer on the film before stretching, the coating layer can be stretched together with the base film, whereby the coating layer can be firmly adhered to the base film. Furthermore, in the production of a biaxially stretched polyester film, the film can be restrained in the longitudinal and lateral directions by stretching while gripping the film end with a clip, etc. High temperature can be applied while maintaining the properties. Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer can be improved, and the coating layer and the base film can be more firmly adhered to each other. Furthermore, the coating layer itself can be made strong, and the performance such as heat and moisture resistance can be improved.

  In the present invention, it is desirable to set the temperature to 150 ° C. or higher when the coated film is dried. If it is less than 150 degreeC, there exists a possibility that sufficient performance may not be obtained because the coating film is insufficiently cured.

  Examples of the method for forming the coating layer of the present invention include gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, and impregnation. Conventionally known coating methods such as coat, kiss coat, spray coat, calendar coat, and extrusion coat can be used.

  In addition, in order to improve the applicability | paintability to the film of a coating agent and adhesiveness, you may give a chemical process, a corona discharge process, a plasma process, etc. to a film before application | coating.

In the case of stretching, the coating amount of the antistatic coating layer is usually 0.005 to 1 g / m ² , preferably 0.01 to 0.3 g / m ² , more preferably 0 in terms of the non-volatile content after stretching. 0.02 to 0.1 g / m ² . If the coating weight is less than 0.005 g / m ² there is a possibility that sufficient performance is obtained, the coating layer in excess of 1 g / m ^2, the worsening of the appearance and transparency, blocking of the film, the cost There is a tendency to invite.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In addition, the evaluation method and the processing method of a sample in an Example and a comparative example are as follows.

(1) Nonvolatile content Approximately 1 g of a sample is taken into an aluminum cup having a diameter of 5 cm and accurately measured. This is heated in a hot air oven at 105 ° C. for 60 minutes. The nonvolatile content is calculated from the change in weight after heating.

(2) Transparency of coating layer (haze increase by coating layer)
According to JIS-K7136, the haze of the film was measured with an integrating sphere turbidimeter NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd. Moreover, the difference of the haze of the film which provided the coating layer and the film which provided the coating layer was calculated, the raise of the haze by providing a coating layer was calculated | required, and it evaluated as the transparency of a coating layer. It can be said that the smaller the haze rise, the better the transparency of the coating layer. In this method, if the haze difference is 0.5% or less, the transparency is excellent, and if it is 0.3% or less, it is particularly excellent. On the other hand, when it exceeds 0.5%, the transparency of the coating layer is slightly inferior, and when it exceeds 1.0%, it is particularly inferior.

(3) Surface resistivity (Ω)
Based on the following method (3-1), the surface resistivity of the film coating layer was measured. In the method (3-1), since a surface resistivity higher than 1 × 10 ⁸ Ω cannot be measured, the method (3-2) was used for a sample that could not be measured in (3-1).
(3-1) Low resistivity meter manufactured by Mitsubishi Chemical Corporation: Loresta GP MCP-T600 was used, and the surface resistivity was measured after conditioning the sample for 30 minutes in a measurement atmosphere of 23 ° C. and 50% RH.
(3-2) Using a high resistance measuring instrument made by Hewlett-Packard Japan: HP4339B and measuring electrode: HP16008B, the surface resistivity was measured after conditioning the sample for 30 minutes in a measurement atmosphere of 23 ° C. and 50% RH. .

(3) Solvent resistance The Taihei Rika Kogyo Co., Ltd. rubbing tester dedicated jig (5cm x 7cm, 500g) is wrapped with a sheet-like cotton (Bencot made by Asahi Kasei Co., Ltd.), and 2ml of solvent is infiltrated there, and an antistatic coating layer. A sample was prepared by wiping the surface of the sample 5 times (15 cm long range). After air drying, the surface resistivity of the rubbed part was measured and compared before and after the treatment.
○: Increase in surface resistivity after treatment is less than 2 times. Δ: Increase in surface resistivity after treatment is 2 times or more and less than 10 times. ×: Increase in surface resistivity after treatment is 10 times or more. Evaluated with ethyl and methyl ethyl ketone (MEK).

(4) Water resistance After the film was immersed in warm water of 40 ° C. for 24 hours, the surface resistivity was measured and compared before and after immersion.
○: Increase in surface resistivity after treatment is less than 2 times Δ: Increase in surface resistivity after treatment is 2 times or more and less than 10 times ×: Increase in surface resistivity after treatment is 10 times or more

(5) Atmospheric exposure test Affixed the test film to the wall of a constant temperature and humidity chamber adjusted to an air temperature of 23 ° C and a relative humidity of 50% so that the measurement surface is opposite to the wall (inside the room), and 14 days have passed. Later, the surface resistivity was measured and compared with that before application.
○: Increase in surface resistivity after treatment is less than 10 times. Δ: Increase in surface resistivity after treatment is 10 times or more and less than 50 times. X: Increase in surface resistivity after treatment is 50 times or more. Was exposed to about 500 lux of white fluorescent light for about 10 hours per day without outdoor light.

The polyester raw materials used in Examples and Comparative Examples are as follows.
(Polyester 1): Polyethylene terephthalate having an intrinsic viscosity of 0.64 substantially containing no particles

(Polyester 2): Polyethylene terephthalate having an intrinsic viscosity of 0.65 containing 0.2% by weight of amorphous silica having an average particle size of 2.4 μm

Moreover, the following was used as a coating composition.
(A1): Conductive agent mainly composed of polyethylene dioxythiophene and polystyrene sulfonic acid, AS-G1 manufactured by Shin-Etsu Polymer Co., Ltd., neutralized with concentrated ammonia water to pH = 9.
(A2): Conductive agent mainly composed of polyethylenedioxythiophene and polystyrenesulfonic acid, AS-G1 manufactured by Shin-Etsu Polymer Co., Ltd.

(B1): Polyglycerin having an average n = 4 in the formula (3) (B2): Compound having an average of 4 molecules of polyethylene oxide added to the polyglycerol skeleton having the formula (3) where n = 2.

(C1): Water-dispersible polyester resin (C2): terephthalic acid / isophthale having a molar ratio of terephthalic acid / isophthalic acid / sulfoisophthalic acid / ethylene glycol / neopentylene glycol in a molar ratio of 49/49/2/50/50 Water dispersible polyester resin in which acid / sulfoisophthalic acid / ethylene glycol / diethylene glycol / triethylene glycol are in a molar ratio of 61/32/7/44/43/13

(D): Nonionic surfactant having a structure having polyethylene oxide in the side chain, represented by the following formula

  In the above formula, m and n are integers indicating the number of moles of ethylene oxide added. Here, the average m + n was 10.

(H1): Polyester polyol composed of 282 parts by weight of terephthalic acid, 282 parts by weight of isophthalic acid, 62 parts by weight of ethylene glycol, and 250 parts by weight of neopentyl glycol, 244 parts by weight of tolylene diisocyanate, 81 of ethylene glycol A polyester polyurethane comprising, as a component, 67 parts by weight of dimethylolpropionic acid and neutralized with ammonia and dispersed in water (concentration 20%, viscosity at 25 ° C., 50 mPa · s).

(H2): Aqueous dispersion of acrylic resin polymerized with the following composition: Emulsification weight of ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (% by weight) Combined (emulsifier: anionic surfactant).

Comparative Example 1:
The mixed raw materials in which polyester 1 and polyester 2 were mixed in proportions of 92% and 8%, respectively, were used as the raw material for the outer layer, and only polyester 1 was used as the raw material for the intermediate layer. After melting, it is co-extruded on a cooling roll set at 40 ° C. in a layer configuration of two types and three layers (outer layer / intermediate layer / outer layer = 1: 10: 1 discharge amount) and cooled and solidified to obtain an unstretched film. It was. This film was stretched 3.7 times in the longitudinal direction while passing through a heating roll group at 85 ° C. to obtain a uniaxially oriented film. This uniaxially oriented film was guided to a tenter stretching machine, stretched 4.3 times in the width direction at 100 ° C., and further heat treated at 230 ° C. to obtain a biaxially oriented polyethylene terephthalate film having a film thickness of 50 μm. The film haze value was 0.6%, and the total light transmittance was 88%.

Example 1:
In the same process as Comparative Example 1, a coating composition as shown in Table 1 below was applied to one side of a uniaxially oriented film after stretching in the longitudinal direction. Next, this film was guided to a tenter stretching machine, and the coating composition was dried using the heat. Thereafter, the same procedure as in Comparative Example 1 was performed, and 0.03 g in a non-volatile content was formed on a base film having a film thickness of 50 μm. A coated film in which an antistatic coating layer in an amount of / m ² was laminated was obtained. The properties of this film are shown in Table 2. When evaluating the transparency of the coating layer, the film haze value of 0.6% of Comparative Example 1 was used as the haze value of the film without the coating layer (the same applies to the following Examples and Comparative Examples).

Examples 2-5:
In the same process as in Example 1, the coating liquid was changed as shown in Table 1, and the non-volatile antistatic coating layer shown in Table 1 was laminated on the base film having a film thickness of 50 μm. Got. The properties of this film are shown in Table 2.

Comparative Examples 2-6:
In the same process as in Example 1, the coating liquid was changed as shown in Table 1, and the non-volatile antistatic coating layer shown in Table 1 was laminated on the base film having a film thickness of 50 μm. Got. The properties of this film are shown in Table 2.

  The coating amount means the non-volatile content of the coating layer composition per area of the finally obtained coating film.

  The film obtained by the present invention can be produced efficiently with in-line coating, has excellent antistatic properties even with a very small amount of conductive agent (compound (A)), and is excellent in economic efficiency. At the same time, transparency, water resistance, and atmospheric exposure resistance are good. Furthermore, it has solvent resistance against ketone-based and ester-based solvents which are important when providing a functional layer.

  The film of the present invention can be suitably used in various applications that require antistatic performance.

Claims (2)

A coating film comprising an antistatic coating layer formed from a coating solution containing the following compounds (A), (B), and (C) on at least one surface of a polyester film.
(A): A polymer obtained by doping a compound comprising thiophene or a thiophene derivative with another anionic compound, or a polymer having an anionic group in a compound comprising a thiophene or thiophene derivative and self-doped.
(B): One or more compounds (C) selected from the group of glycerin (b1), polyglycerin (b2), glycerin or alkylene oxide adduct (b3) to polyglycerin, and polyalkylene oxide (b4): Polyester resin The polyester film according to claim 1, wherein the coating layer is stretched in at least one direction.