WO2006104126A1

WO2006104126A1 - Laminated thermoplastic resin film roll and process for production thereof

Info

Publication number: WO2006104126A1
Application number: PCT/JP2006/306230
Authority: WO
Inventors: Naoki Mizuno; Shigenori Iwade; Hiroshi Taki; Chikao Morishige; Yasuhiro Nishino; Katsuhiko Nose
Original assignee: Toyo Boseki Kabushiki Kaisha
Priority date: 2005-03-28
Filing date: 2006-03-28
Publication date: 2006-10-05
Also published as: JP2006272676A; JP4315118B2

Abstract

[PROBLEMS] To provide a laminated thermoplastic resin film roll having fewer optical defects and a process for the production of the roll. [MEANS FOR SOLVING PROBLEMS] A laminated thermoplastic resin film roll which is a roll-shaped product of a laminated film obtained by forming a coating layer comprising a resin component containing a copolyester resin or both a copolyester resin and a polyurethane resin and particles on at least one side of a thermoplastic resin film substrate, characterized in that the number of contained foreign particles which are 0.3 mm or above in length and are made mainly of both the above resin component and the above particles is 30/100m2 or below; and a process for the production of the roll, which comprises filtering the copolyester resin solution to be used in preparing a coating fluid for the formation of a coating layer with a filter having a precision (particle size) of 0.5μm to 10μm under the conditions of solution temperature of 15˚C or above but below 35˚C, heating the filtrate to a temperature of 50˚C or above but below 70˚C, and then filtering the resulting filtrate with a filter having a precision (particle size) of 0.5μm to 10μm under the conditions of 15˚C or above but below 35˚C.

Description

Specification

Laminated thermoplastic film roll and method for producing the same

Technical field

[0001] The present invention is mainly used for display-related applications, such as antireflection film, light diffusion sheet, prism sheet, infrared absorption film, electromagnetic wave shielding film, transparent conductive film, antiglare film, etc. Coating layer, light diffusing layer, prism layer, infrared ray absorbing layer, electromagnetic wave shielding layer, transparent conductive layer, anti-glare layer, etc.) The present invention relates to a laminated thermoplastic resin film roll having excellent transparency with few optical defects due to foreign matter.

Background art

[0002] In general, the base material of an optical functional film used for a display member such as a liquid crystal display (LCD) or a plasma display panel (PDP) includes polyethylene terephthalate (PET), acrylic polymer, polycarbonate (PC). A transparent film having triacetyl cellulose (TAC), polyolefin and the like is used. When these base films are used for various optical functional films, functional layers according to various uses are laminated on the base film. For example, a protective film (hard coat layer) that prevents scratches on the surface, an antireflection layer (AR layer) that prevents external light from being reflected, a prism layer used to collect and diffuse light, and to improve brightness Examples thereof include a functional layer such as a light diffusion layer. Among these base materials, in particular, the biaxially oriented polyester film is widely used as a base material for various optical functional films from the viewpoint of excellent transparency, dimensional stability, and chemical resistance.

[0003] Generally, in the case of a biaxially oriented thermoplastic film such as a biaxially oriented polyester film or a biaxially oriented polyamide film, the film surface is highly crystallized, so various coatings, adhesives, inks, etc. There is a drawback of poor adhesion. For this reason, various methods have been proposed for imparting easy adhesion to the surface of a biaxially oriented thermoplastic resin film.

[0004] In addition, a film having no polar group, such as a polyolefin film, has very poor adhesion to various paints, adhesives, inks, etc., so that corona discharge treatment and flame treatment should be performed in advance. After any physical treatment or chemical treatment, a method for imparting easy adhesion to the film surface by various methods has been proposed.

[0005] For example, on the surface of the thermoplastic resin film of the base material, various types of resin such as polyester, acrylic, polyurethane, and acrylic graft polyester are used as the main constituent components of the coating layer, and the above-mentioned base material film is coated with a coating method. A method of imparting easy adhesion to a base film by providing a coating layer is generally known. Among these coating methods, a dispersion in which a thermoplastic resin film before completion of crystal orientation is subjected to corona discharge treatment directly or as necessary, and then the resin solution or resin is dispersed in a dispersion medium. A method of coating a base film with an aqueous coating solution containing, drying, stretching at least uniaxially, and then applying heat treatment to complete the crystal orientation of the thermoplastic resin film (so-called in-line coating method) In addition, after manufacturing a thermoplastic resin film, a method of applying a water-based or solvent-based coating solution to the film and then drying (so-called off-line coating method) is widely used industrially.

[0006] In particular, the biaxially oriented polyester film has poor adhesion to a coating agent mainly composed of an acrylic resin used in prism lenses, hard coats, etc. In order to improve this, a polyester film is used. Various types in which a coating layer made of polyurethane-based resin or the like is formed on the surface have been proposed (see, for example, Patent Document 1). However, when the coating layer made of the polyurethane-based resin is formed, the adhesion with a functional layer such as a hard coat layer is improved, but the adhesion with the polyester film as a substrate is insufficient. In particular, there is a problem that the adhesion at the interface between the coating layer and the functional layer becomes insufficient. Furthermore, foreign matters such as dust and particle aggregates for the purpose of imparting easy slipping may be mixed or adhered in the coating layer or on the surface of the coating layer, often resulting in optical defects.

[0007] In addition, a resin composition layer mainly comprising polyester resin and polyurethane resin is provided on a base film made of biaxially oriented polyethylene terephthalate by an in-line coating method, and a base polyester film is provided. A method for improving the adhesion to a functional layer such as ink has been proposed (see, for example, Patent Document 2). Specifically, after applying a water-dispersible coating solution containing a copolymerized polyester resin and a polyurethane-based resin (= 20Z80; mass%) to a polyester film stretched uniaxially in the longitudinal direction, the polyester film is guided to a tenter and dried. Horizontal extension After stretching, it is heat-set at 220 ° C to obtain an easily adhesive biaxially oriented polyester film. However, in the method described in Patent Document 2, although the adhesion is improved, foreign matters such as dust and aggregates of particles for imparting slipperiness are mixed or attached to the coating layer or the coating layer surface. In many cases, it was worn, resulting in optical defects.

[0008] The optical defect becomes more conspicuous as the transparency of the laminated film is improved and the haze is reduced. Therefore, when the films described in Patent Document 1 and Patent Document 2 are used particularly as an optical substrate film, It is inferior in quality and cannot satisfy practical characteristics.

[0009] Further, in recent years, particularly for optical films, high value-added films having a composite function in which different functions are provided on both sides of a single sheet have been required for light weight and low cost. ing. For example, it is a composite function film having a plurality of functions such as a light diffusion function, a condensing function, a near-infrared absorption function, an electromagnetic wave blocking function, etc. on the opposite side in addition to a scratch prevention function and an antifouling function on one side. Since such a multi-functional film has a high degree of processing, even if it has a relatively large size of 0.3 mm or more and a small occurrence frequency, for example, several tens of defects per 100 m ² , Economic losses are extremely large, and there is a strong demand for improvement. In addition, with the increase in the size of displays and the like, even with the same frequency of defects, the product defect rate has greatly increased, and there is a strong demand for improvement.

[0010] The present applicant performs high-accuracy filtration on the coating solution for laminating the molten resin and the resin composition at the time of forming the base film, and is a base made of biaxially oriented polyethylene terephthalate. Transparency, which is a very important property as an optical substrate film, is provided with a resin composition layer on which a polyester resin, a polyurethane-based resin, and inorganic particles with an appropriate particle size are added. We have proposed a laminated polyester film that can satisfy the required level of adhesion from the market while maintaining it, and has few optical defects (see, for example, Patent Documents 3 and 4). Specifically, a polyester film stretched uniaxially in the machine direction obtained using polyethylene terephthalate resin filtered with a stainless steel sintered filter medium having a filtration particle size (initial filtration efficiency 95%) 15 m. copolyester榭脂, polyurethane榭脂(= 20/80; weight ^_0/0) and the water-dispersible coating solution containing two kinds of silica particles having different average particle sizes, filtration particle size (initial filtration efficiency 95 %) 25 μm felt An easy-adhesive biaxially oriented polyester film obtained by filtering with a type polypropylene filter material, coating, guiding to a tenter, drying, transverse stretching, and heat setting at 240 ° C. was disclosed. These easy-adhesive biaxially oriented polyester films obtained in Patent Documents 3 and 4 have excellent adhesion and transparency, and optical defects such as foreign matters and scratches are greatly improved. Satisfying the properties that were made. However, as mentioned above, with the recent reduction in cost and the increase in the display screen, the current demand for the factory is that a relatively large (0.3 mm or more) optical defect cannot be tolerated even if the frequency of occurrence is small. Quality has not been able to be fully addressed.

[0011] Further, in order to improve the uniformity of adhesion, the applicant of the present invention has proposed an invention relating to an easily adhesive film roll in which the variation in the coating amount of the coating layer is reduced (see, for example, Patent Document 5). . More specifically, the polyester film is uniaxially stretched in a longitudinal direction, polyester榭脂a polyurethane榭脂(= 50Z50; Mass ^_0/0), silica particles having an average particle size of 1. 4 m, and fluorine-based surfactants A water-dispersible coating solution containing an activator was dried in a drying oven at 120 ° C and stretched laterally after application, and then heat-set at 220 ° C.

An axially oriented polyester film has been disclosed. The obtained film roll had excellent adhesion uniformly throughout the film roll, and satisfied the required level from the factory. However, even with this method, the required quality of the current market for the optical defects of the above-mentioned size of 0.3 mm or larger and relatively small occurrence frequency has not been able to sufficiently meet the requirements.

[0012] In Patent Document 6, the coating liquid mainly composed of copolymerized polyester resin is filtered through a polypropylene filter having a filtration accuracy of 0.2 μm force and 3 μm to aggregate in the coating liquid. Except for items, the application stripes are reduced by using a gravure roll that rotates backward at a peripheral speed of about 1.2 times the film speed. However, even with this method, it has become impossible to sufficiently meet the required quality of the current factory for the optical defects with low occurrence frequency.

[0013] The cause of the occurrence of the optical defect is unknown, and no matter how highly accurate the filtration process is performed on the coating solution, the optical defect cannot be reduced only by the filtration process. Patent Document 1: JP-A-6-340049

Patent Document 2: Japanese Patent Publication No. 64-6025

Patent Document 3: Japanese Unexamined Patent Publication No. 2000-323271

Patent Document 4: Japanese Patent Laid-Open No. 2000-246855

Patent Document 5: Japanese Unexamined Patent Application Publication No. 2004-10669

Patent Document 6: Japanese Unexamined Patent Application Publication No. 2002-172362

Disclosure of the invention

Problems to be solved by the invention

[0014] In view of the above problems of the prior art, the problem to be solved by the present invention is to provide a laminated thermoplastic resin film roll with few optical defects and a method for producing the same.

Means for solving the problem

[0015] As a result of intensive research on the cause of optical defects that are relatively large and having a small occurrence frequency of 0.3 mm or more and the means for preventing the occurrence, the present inventors have achieved the present invention. It came.

[0016] Generally, as a coating method in which a coating layer is laminated on one or both sides of a base film, a reverse roll coating method, a gravure 'coating method, a kiss' coating method, a roll brush method, a spray coating method, an air knife coating Method, wire bar coating method, doctor blade method, impregnation. Coating method and curtain 'coating method, etc. Among them, a smooth coating surface with a uniform coating layer thickness is obtained, and a reverse roll suitable for functional coating immediately. 'Coating method, gravure coating method, kiss coating method and doctor method are widely used especially for applications that require high quality such as optical base film. In these coating methods, a doctor blade 6 is installed as shown in FIG. 1, for example, in order to remove excess coating solution on the roll or the substrate film. In such an apparatus, the cause of the occurrence of an optical defect having a major axis of 0.3 mm or more and a low occurrence frequency is estimated as follows.

[0017] When the solid matter mainly containing the resin component and particles contained in the coating liquid is deposited on the doctor blade 6, and when the solid matter reaches a certain accumulation amount or more, the solid matter falls off from the doctor blade. Attached to the base film through a coater roll or directly, Serious optical defects occur. In other words, no matter how high-precision filtration treatment is applied to the coating liquid within the practical range, only the filtration treatment can be applied to the doctor blade 6 of the coater with a solid component mainly composed of the resin component and particles of the coating liquid. It was impossible to reduce the precipitation of objects. In particular, it has been found that the frequency of occurrence increases when the low-molecular-weight component is contained in the rosin component contained in the coating solution.

[0018] The present invention reduces the precipitation of the coagulant component, which has heretofore been avoided by filtration alone, on the doctor blade by subjecting the copolyester resin to a high degree of refining treatment. We have achieved a reduction in optical defects that can be a serious but significant optical defect.

That is, the above-described problem can be achieved by the following solution means.

[0020] A first invention is a resin composition comprising a thermoplastic resin film as a base material, and a copolymer polyester resin or a copolymer polyester resin and a polyurethane resin on at least one surface of the base material, And a roll of a laminated film provided with a coating layer containing particles, and the content of foreign matter having a major axis of 0.3 mm or more whose major component is a coating layer resin component and particles is 30 Z 100 m ² or less It is the laminated thermoplastic resin film roll characterized by being.

[0021] A second invention is the film roll according to the first invention, wherein the winding length is 1500 m or more and the width is 0.5 m or more.

[0022] In the third invention, the laminated thermoplastic resin according to the first invention or the second invention, wherein the particles contained in the coating layer are particles made of silicon oxide. Is a film roll

[0023] The fourth invention is characterized in that the thermoplastic resin film substrate substantially does not contain particles, and the first invention power is the laminated thermoplastic resin according to any one of the third inventions. It is a sorghum film roll.

[0024] According to a fifth invention, in any one of the first to fourth inventions, the copolymerized polyester resin is a copolymerized polyester resin having a low content of low molecular weight components. It is the laminated thermoplastic resin film roll described.

[0025] According to a sixth aspect of the present invention, there is provided a copolymer polyester resin in which a solution of the copolymer polyester resin is filtered at a liquid particle size of 0. below Filter with a filter, heat to 50 ° C or higher and lower than 70 ° C, and further filter with a filter with a particle size of 0. to 10 m under conditions of 15 ° C or higher and less than 35 ° C. A laminated thermoplastic resin film roll according to the fifth invention, characterized in that it is obtained by refining.

[0026] The seventh invention relates to one side of a traveling thermoplastic resin film or a coating liquid containing a resin component containing copolyester resin resin or copolymer polyester resin and polyurethane resin, and particles. Lamination heat formed through a coating process for coating on both sides, a drying process for drying the coating layer, a stretching process for stretching in at least a uniaxial direction, and a thermosetting process for thermally fixing the stretched coating film. A method for producing a plastic resin film roll, wherein a copolymerized polyester resin is a solution of a copolymerized polyester resin, with a filtration particle size of not less than 0. After filtering with a filter of 10 m or less and heating to 50 ° C or more and less than 70 ° C, the filter particle size is 0. or more and 10 m or less under conditions of 15 ° C or more and less than 35 ° C. Obtained by filtering through a filter Characterized in that the those, a laminated thermoplastic 榭脂 film roll manufacturing method.

[0027] According to an eighth aspect of the present invention, there is provided one surface of a thermoplastic resin film that travels with a coating liquid containing a resin component and particles containing a copolyester resin resin or a copolyester resin resin and a polyurethane resin. It includes a coating process for coating on both sides, a drying process for drying the coating layer, a stretching process for stretching in at least a uniaxial direction, and a thermosetting process for thermally fixing the stretched coating film. However, the solution of copolymer polyester resin is filtered through a filter with a particle size of 0. to 10 m under conditions of liquid temperature of 15 ° C or more and less than 35 ° C, and 50 ° C or more and 70 ° C. And then filtered through a filter with a filter particle size of 0.5 μm or more and 10 μm or less under conditions of 15 ° C or more and less than 35 ° C. From the first invention to the fifth invention, characterized in that A method for producing a laminated thermoplastic 榭脂 film roll according to any one.

[0028] The ninth aspect of the invention is the production according to the eighth aspect of the invention, which is carried out by a coating force, reverse roll coating method, gravure 'coating method, kiss' coating method, offset coating method or a combination of these methods. Is the method. [0029] The tenth invention is characterized in that, in the coating step, an application roll having a surface roughness of 0.1 S or less and a roundness of ZlOOOOmm or less and a metering roll are used in the coating apparatus. The manufacturing method according to the eighth or ninth invention.

The invention's effect

[0030] The laminated thermoplastic resin film roll of the present invention has few optical defects, is excellent in adhesion and maintains a uniform surface quality, and is particularly suitable for use as an optical functional film or a substrate film of a sheet. Useful. Moreover, according to the manufacturing method of this invention, this laminated thermoplastic resin film roll can be manufactured effectively.

Brief Description of Drawings

FIG. 1 is a schematic view of a coating apparatus for forming a coating layer in the laminated thermoplastic resin film of the present invention.

FIG. 2 is a layout view of a preparation tank, a circulation tank, and a coater of a coating apparatus for forming a coating layer in the laminated thermoplastic resin film of the present invention.

Explanation of symbols

[0032] 1 Base film 2 Applicator roll 3 Metering roll 4 Fountain die 5 Coating liquid guide plate 6 Doctor blade 7 Coating liquid tray 8 Coater cover 9 Preparation tank 10 Defoaming branch pipe 11 Circulation tank 12 Filter 13 Pinch roll BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described.

[0034] The present invention comprises a resin component comprising a thermoplastic resin film as a base material, and containing a copolymer polyester resin or a copolymer polyester resin and a polyurethane resin on at least one side of the base material, and particles A roll of a laminated film provided with a coating layer containing a coating material, wherein the content of foreign matter having a major axis of 0.3 mm or more whose major component is a coating layer resin component and particles is 30 Z100 m ² or less This is a laminated thermoplastic resin film roll.

(Substrate) In the present invention, the thermoplastic resin film used as the substrate refers to an unoriented sheet obtained by melt-extrusion or solution-extrusion of a thermoplastic resin, as required, in the longitudinal direction or width. Stretched uniaxially, or sequentially biaxially or biaxially stretched biaxially A film subjected to heat setting treatment.

[0036] The thermoplastic resin film does not impair the object of the present invention! / Within the range, such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ozone treatment, etc. It may be activated.

[0037] The thickness of the thermoplastic resin film used as the substrate can be arbitrarily determined in the range of 30-300 μm according to the specifications of the application to be used. The upper limit of the thickness of the thermoplastic resin film is preferably 250 μm, particularly preferably 200 μm. On the other hand, the lower limit of the film thickness is preferably 50 μm, particularly preferably 75 μm. If the film thickness is less than 30 μm, rigidity and mechanical strength tend to be insufficient. On the other hand, if the film thickness exceeds 300 m, the absolute amount of foreign matter present in the film increases, and the frequency of optical defects increases. In addition, the slitting property when the film is cut to a predetermined width is deteriorated, and the manufacturing cost is increased. Furthermore, since the rigidity is increased, it is difficult to wind a long film into a roll.

[0038] Thermoplastic resin includes polyethylene (PE), polypropylene (PP), polymethylpentene

Polyolefins such as (TPX), Polyethylene terephthalate (PET), Polyethylene 2, 6 Naphthalate (PEN), Polypropylene terephthalate (PTT), Polybutylene terephthalate (PBT), etc. Polyester resin, Nylon 6, Nylon 4, Nylon Polyamide (PA) resin such as 66, nylon 12, polyimide (PI), polyamideimide (PAI), polyethersulfone (PES), polyetheretherketone (PEEK), polycarbonate (PC), polyarylate (PAR) , Cellulose propionate, polychlorinated butyl (PVC), poly (vinyl chloride), poly (butyl alcohol) (PVA), polyether imide (PEI), poly-phenylene sulfide (PPS), poly-phenylene oxide, polystyrene (PS) ), Syndiotactic polystyrene, and norbornene-based polymers. These thermoplastic rosins are copolymers containing a small amount of copolymer components.

Also good. In addition to using these thermoplastic resins alone, one or more other thermoplastic resins may be blended and used.

[0039] Among these thermoplastic resins, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyethylene 2, 6 naphthalate, syndiotactic Tick polystyrene, norbornene-based polymer, polycarbonate, polyarylate and the like are suitable. In addition, a resin having a polar functional group such as polyester or polyamide is also preferable from the viewpoint of adhesion to the covering layer. In particular, polyethylene terephthalate, polyethylene 2,6 naphthalate, polybutylene terephthalate, polypropylene terephthalate or a copolymer mainly composed of components of these resins is preferably used as the base material. The formed biaxially oriented film is most preferred.

[0040] When a polyester copolymer is used as a resin for forming a thermoplastic resin film, for example, as its carboxylic acid component, an aliphatic dicarboxylic acid such as adipic acid or sebacic acid, terephthalic acid, isophthalic acid, phthalic acid, etc. Acids, aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, and polyfunctional carboxylic acids such as trimellitic acid and pyromellitic acid are used. As glycol components, fatty acid glycols such as ethylene glycol, diethylene glycol, 1,4 butanediol, propylene glycol, and neopentyl glycol; p aromatic glycols such as xylene glycol; and alicyclics such as 1,4-cyclohexanedimethanol. Glycol: Polyethylene glycol having an average molecular weight of 150 to 20000 is used. An example of the copolymer composition ratio in the monomer components constituting the polyethylene terephthalate, the other comonomer component below 20 mole ^_0/0 (when the comonomer component is a carboxymethyl phosphate component is best carboxylic acid component. It is preferable to add the same as when the comonomer component is a glycol component). Above 20 mol%, film strength, transparency, and heat resistance may be inferior. A predetermined amount of the above-mentioned carboxylic acid component and glycol component is prepared and used as a catalyst, for example, alkaline earth metal compound, manganese compound, cobalt compound, aluminum compound, antimony compound, titanium compound. Polyester copolymers are produced using compounds, titanium Z-silicon complex oxides, germanium compounds, and the like.

[0041] Further, in the production of the base material, various additives other than the catalyst and other additives can be blended with the thermoplastic resin in a range not impeding the effects of the present invention. Examples of additives include inorganic particles, heat-resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, UV absorbers, light-resistant agents, flame retardants, heat stabilizers, and oxidation. Examples thereof include an inhibitor, an antigelling agent, and a surfactant.

[0042] The inorganic particles and the heat-resistant polymer particles are used in the production of thermoplastic resin films or in rolls. In order to give moderate surface irregularities to the film surface from the viewpoint of handling properties (sliding property, running property, blocking property, air escape of accompanying air at the time of removing), etc. Used.

[0043] Inorganic particles include calcium carbonate, calcium phosphate, amorphous silica, crystalline glass filler, kaolin, talc, titanium dioxide, alumina, silica-alumina composite oxide particles, barium sulfate, calcium fluoride, fluorine. Lithium fluoride, zeolite, molybdenum sulfate, My power, etc. The heat-resistant polymer particles include cross-linked polystyrene particles, cross-linked acrylic resin particles, cross-linked methyl methacrylate particles, benzoguanamine 'formaldehyde condensate particles, melamine' formaldehyde condensate particles, polytetrafluoroethylene particles. Etc.

[0044] When a polyester film is used as the base film, among the above particles, the silica particles are relatively close to the polyester resin and have a relatively high refractive index, so that it is easy to obtain high transparency. Most preferred. Further, the particles contained in the thermoplastic resin film may be used alone or in combination of two or more.

[0045] The type, average particle size, and addition amount of the above-mentioned particles should be determined according to the application, particularly the average particle size is 0.01-2 / ζ πι. The particle content in the film may be determined in the range of 0.01 to 5.0% by mass. In addition, when the laminated thermoplastic resin film of the present invention is used for applications in which transparency is highly required, particles that cause a decrease in transparency are included in the thermoplastic resin film of the substrate. It is preferable that the coating layer contains particles without substantially containing (that is, the particles are not blended with the base material). “Substantially no particles are contained in the thermoplastic resin film of the substrate” means, for example, in the case of inorganic particles, 50 ρρ m or less, preferably when inorganic elements are quantified by key X-ray analysis. Means a content of 10 ppm or less, most preferably below the detection limit. This is because contaminants derived from foreign substances may be mixed without positively adding particles to the base film.

[0046] The layer structure of the thermoplastic resin film used as the substrate in the present invention may be a single layer, or may be a laminated structure in order to provide a function that cannot be obtained with a single layer. In the case of a laminated structure, a coextrusion method is preferable. [0047] Examples of the method for producing the thermoplastic resin film of the substrate include the following methods. The pellets of thermoplastic resin containing particles or substantially free of particles are sufficiently dried in vacuum, then supplied to an extruder, melt-extruded into a sheet at a temperature equal to or higher than the melting temperature, cooled and solidified, and unoriented. A thermoplastic resin sheet is formed into a film. At this time, high-precision filtration is performed at any place where the molten resin is removed in order to remove foreign substances contained in the resin. The obtained unoriented sheet is stretched 2.5 to 5.0 times in the longitudinal direction with a roll heated to the glass transition point or higher to obtain a uniaxially oriented thermoplastic resin film.

[0048] Further, the production method for obtaining the base film will be described in detail below, using polyester as a raw material for the thermoplastic resin film as a representative example.

[0049] The intrinsic viscosity of the polyester pellets used as the base film raw material is preferably in the range of 0.45 to 0.7 dl / g. More preferably, from the viewpoint of mechanical strength and film-forming stability, the intrinsic viscosity is from 0.50 dl to 0.7 dlZg, more preferably from 0.55 to 0.7 dl / g, and most preferably from 0.60 to 0.7 dlZg. It is. If the intrinsic viscosity is less than 0.45 dlZg, the film tends to break during film production, resulting in decreased productivity and thermal shrinkage characteristics. On the other hand, if the intrinsic viscosity exceeds 0.7 dlZg, the filtration pressure will increase and it will be difficult to perform high-precision filtration, resulting in decreased productivity.

[0050] In addition, when used in an optical functional film or sheet, it is preferable to remove foreign substances contained in the raw material polyester that cause optical defects. In order to remove foreign substances in the polyester, high-precision filtration is performed at an arbitrary place where the molten resin is kept at about 280 ° C during melt extrusion. The filter medium used for high-precision filtration of molten resin is not particularly limited, but aggregates mainly composed of Si, Ti, Sb, Ge, and Cu and high-melting-point organic substances in the case of stainless steel sintered filter media are removed. Excellent performance and suitable.

[0051] The filtration particle size (initial filtration efficiency: 95%) of the filter medium used for high-precision filtration of the molten resin is preferably 15 μm or less. When the filter particle size of the filter medium exceeds 15 μm, the removal of foreign matters of 20 μm or more tends to be insufficient. Productivity may be reduced by high-precision filtration of molten resin using filter media with a filtration particle size (initial filtration efficiency: 95%) of 15 m or less. To obtain a film with few optical defects. is important.

[0052] In the process of extruding the molten resin, even a fine foreign material that passes through the filter medium is in the form of a sheet. Crystallization proceeds around the foreign material in the cooling process of the melt, and this causes non-uniformity of alignment in the alignment process, causing a small difference in thickness and resulting in a lens state. Here, the light is refracted or scattered as if it were a lens, and when viewed with the naked eye, it appears larger than the actual foreign object. This minute difference in thickness can be observed as the difference between the height of the convex part and the depth of the concave part. The height of the convex part is 1 m or more and the depth of the concave part adjacent to the convex part is 0. In this case, due to the lens effect, even an object having a size of 20 / zm is visually recognized as a size of 50 μm or more, and is further recognized as an optical defect of a size of 100 μm or more. In some cases.

[0053] In order to obtain a highly transparent film (especially a film having a haze of less than 1.5%), it is preferred not to include particles in the base film, but the particle content is low and transparency is high. The optical defects due to minute irregularities tend to become clearer.

[0054] In addition, since the surface of a thick film is more rapidly cooled than a thin film and tends to undergo crystallization, it is necessary to rapidly cool the entire film when manufacturing an unoriented sheet. As a method for cooling the non-oriented sheet, the molten resin is extruded into a sheet form from the slit portion of the foundation on the rotating cooling drum, and the sheet-like melt is brought into close contact with the rotating cooling drum and rapidly cooled to form a sheet. Is preferred. As a method of cooling the air surface (the surface opposite to the surface in contact with the cooling drum) of the unoriented sheet, a method of cooling by blowing a high-speed air current is effective.

[0055] The obtained unoriented sheet is stretched 2.5 to 5.0 times in the longitudinal direction with a roll heated to a glass transition point or higher to obtain a uniaxially oriented thermoplastic resin film (polyester film in this example). .

(Copolymerized polyester resin) The copolymerized polyester resin used for the coating layer of the present invention preferably comprises an aromatic dicarboxylic acid component and ethylene glycol and branched glycol as glycol components. Examples of the branched glycol component include 2,2 dimethyl-1,3 propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-methyl-2 butyl-1,3 propanediol, 2-methyl-2-propyl- 1, 3 Propanediol, 2-Methyl-2-isopropyl 1,3 Propanediol, 2-Methyl-2-n Xylou 1, 3 Propanediol, 2, 2 Jetyl 1,3 Propanediol, 2 Ethyl 2— n-Butyl 1,3 Propandiol, 2 Ethyl 2—n Xylou 1,3 Propanediol, 2, 2 Di n-Butyl 1,3 Propanediol, 2— n —Butyl-2-propyl 1,3 puffer diol and 2,2 xy xyru 1,3 propane diol.

[0057] The molar ratio of the branched glycol component is preferably 20 mol%, with the lower limit being preferably 10 mol% with respect to the total glycol component. On the other hand, the upper limit is preferably 80 mol%, more preferably 70 mol%, and particularly preferably 60 mol%. If necessary, diethylene glycol, propylene glycol, butanediol, hexanediol or 1,4 cyclohexanedimethanol may be used in combination!

[0058] As the aromatic dicarboxylic acid component, terephthalic acid and isophthalic acid are most preferable.

Other aromatic dicarboxylic acids, especially diphenyl carboxylic acid, 2, 6 naphthalene dicarboxylic acid and other aromatic dicarboxylic acids are copolymerized within a range of 10 mol% or less with respect to the total dicarboxylic acid component. Well ...

[0059] In producing the copolyester, a polymerization catalyst such as an antimony compound, an aluminum compound, a titanium compound, or a germanium compound can be used.

[0060] The copolyester resin used as the resin component of the coating layer in the present invention is preferably a water-soluble or water-dispersible resin. Therefore, in addition to the dicarboxylic acid component, 5-sulfoisophthalic acid or an alkali metal salt thereof is used in a range of 110 mol% with respect to the total dicarboxylic acid component in order to impart water dispersibility to the polyester. Preferred examples include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4

Examples include naphthaphthalene 2,7 dicarboxylic acid and 5- (4-sulfophenoxy) isophthalic acid or alkali metal salts thereof.

[0061] In general, copolymerized polyester resin has an aromatic dicarboxylic acid component (for example, terephthalic acid) and ethylene glycol trimer, pentamer, hexamer, aromatic dicarboxylic acid component (for example, , Terephthalic acid) and branched glycols (eg, neopentyldaricol), which contain many low molecular weight components such as tetramers. In some cases, metal oxides, metal hydroxides, and the like produced from the polymerization catalyst of the copolyester are mixed as an applicator roll, dried on a metalling roll, solidified, and deposited on the doctor blade surface. It is presumed that the above-mentioned serious optical defect occurs due to dropping from the doctor blade and adhering to the base film through a coater roll or directly. Therefore, low molecular weight component of copolymerized polyester resin in coating liquid

Reducing the content of (hexamer or lower component) and thereby reducing the precipitation of solid matter on the doctor blade is necessary for obtaining a thermoplastic resin film roll with less optical defects defined by the present invention. is important.

Therefore, in the present invention, a copolymer polyester resin having a reduced content of low molecular weight components is used. The method for reducing the content of the low molecular weight component of the copolyester resin is not particularly limited, but the copolyester resin is dissolved in a solvent to form a solution, and the solution temperature is 15 ° C or higher. Filter with a filter particle size of 0.5 / zm or more and 10 m or less under the condition of less than 35 ° C, then warm to 50 ° C or more and less than 70 ° C, then further 15 ° C or more, 35 A method of filtering with a filter having a filtration particle size of not less than 0 and not more than 10 μm under a condition of less than ° C is preferred.

[0063] The solvent for dissolving the copolymerized polyester resin in a solvent is not particularly limited as long as the copolymerized polyester resin is dissolved. For example, a water-soluble or water-dispersible polyester resin Alcohols such as water, ethanol, isopropyl alcohol, and benzyl alcohol can be preferably used, and water and isopropyl alcohol are most preferable.

[0064] For example, the solution koji is prepared by adding a solvent to the copolymerized polyester resin and stirring to obtain a copolymerized polyester resin solution having a solid content of 20 to 40% by mass, preferably 25 to 35% by mass. This solution is allowed to stand as it is to precipitate coarse oligomer aggregates. The standing time is preferably 5 to 20 days, and the standing temperature is preferably less than 35 ° C. Above 35 ° C, the low molecular weight oil component may not be sufficiently precipitated. About 9/10 of the supernatant is preferably taken from this set and left for filtration. The supernatant is water or a mixed solvent of water and an organic solvent (eg, ethanol, isopropyl alcohol, benzyl alcohol, etc.) before filtration until the solution viscosity is 5 cps or more and less than 15 cps. Diluted with If it is 15 cps or more, the load on the filter and pump in the filtration process described later is increased, and the processing efficiency is inferior. On the other hand, if it is less than 5 cps, the dilution rate becomes large, and the amount of filtration treatment becomes unnecessarily large. The solution viscosity here is the value at 25 ° C when using a B-type viscometer (BL type) No. 1 adapter manufactured by Tokyo Keiki Co., Ltd.

[0065] The diluted solution is subjected to microfiltration. Oligomer agglomerates generated during the standing period by microfiltration treatment, and metal components (metal oxide, metal hydroxide crystals, etc.) that are copolymerization catalysts for copolymer polyester when added. Is removed. The filter medium used for the microfiltration has a filtration particle size (initial filtration efficiency: 95%) of 10 μm or less and 0.5 m or more, preferably 5 μm or less and 1 μm or more. is there. It is more preferable to use a combination of two or more filters having different filtration performance within the range. When the filtered particle size exceeds 10 m, removal of coarse oligomer aggregates tends to be insufficient. When the filtration performance is less than 0.5 m, even necessary particle aggregates are removed, and the originally required slipperiness and blocking resistance may be lowered, which is not preferable. When filters with different filtration performance are used in combination, it is effective to use a filter with the size of the filter particle size and the filter power gradually reduced. There are no particular limitations on the type of filter medium for finely filtering the coating liquid as long as it has the above performance, and examples include a filament type, a felt type, and a mesh type. The material of the filter medium for finely filtering the coating solution is not particularly limited as long as it has the above-described performance and does not adversely affect the coating solution. Examples thereof include stainless steel, polyethylene, polypropylene, and nylon. The temperature of the copolyester solution during filtration is 15 ° C or higher and lower than 35 ° C, preferably 20 ° C or higher and lower than 35 ° C. Above 35 ° C, the oligomer dissolves and its removal is insufficient. When it is below 15 ° C, the liquid viscosity increases and the filtration efficiency decreases, which is not preferable. The number of times of filtration through the filter is 2 times or more, preferably 5 times or more, more preferably 20 times or more. There is no upper limit to the number of filtrations, but considering the efficiency, the maximum is about 50 times.

[0066] In this case, the copolyester solution filtrate is heated to 50 ° C or higher and lower than 70 ° C, preferably 55 ° C or higher and lower than 65 ° C, and it is difficult to remove by filtration. Molecular weight oil component And the catalytic metal compound is dissolved. Below 50 ° C, low molecular weight compounds and catalytic metal compounds cannot be sufficiently dissolved. Above 70 ° C, the copolymerized polyester component is likely to be altered, which is not preferable. At this time, it is preferable to stir as necessary in order to keep the temperature of the solution uniform. The heating time is preferably 1 hour or more and less than 3 hours. If it is less than 1 hour, you will not get a sufficient effect! In addition, it is not preferable that the copolymerized polyester resin is deteriorated for more than 3 hours.

[0067] Thereafter, the temperature is lowered and the mixture is allowed to stand to precipitate fine low molecular weight components, and then the microfiltration treatment is performed again. This refiltration treatment removes the low-molecular-weight component aggregates and catalyst metal compound crystals that have been regenerated. The standing time is preferably 2 to 10 hours, and the standing temperature is preferably less than 30 ° C. The upper limit of the filter particle size (initial filtration efficiency: 95%) of the filter used for the refiltration treatment is 10 m, preferably 3 m, and the lower limit is 0.5 μm, preferably 1 μm. The filtration temperature is a temperature close to a preferable liquid temperature at the time of coating, specifically, 15 ° C or higher and lower than 35 ° C, preferably 20 ° C or higher and lower than 35 ° C. Further, the number of times of filtration passing through the filter is 2 times or more, preferably 5 times or more, more preferably 20 times or more. There is no upper limit on the number of times of filtration, but considering the efficiency, the maximum is about 50 times.

[0068] Confirmation that the content of the low molecular weight component of the copolymerized polyester resin is reduced can be confirmed by measuring the haze of the above-mentioned heat-filtered copolymerized polyester resin solution. . Specifically, the haze of the copolymerized polyester resin solution was measured with a haze meter (Nippon Denshoku model TNDH2000) using a 10 mm (quartz cell optical path length) cell, and the haze was 5% or less. If so, it can be judged that the content of the low molecular weight component is reduced.

[0069] Other means for reducing the low molecular weight component of the copolyester resin resin include fractionation by liquid chromatography.

[0070] The optical defects defined by the present invention are effectively obtained by using a copolymerized polyester resin having a low content of low molecular weight components obtained by a purification treatment as exemplified above in the coating step. Can be obtained.

(Polyurethane resin) Polyurea used for the coating layer of the laminated thermoplastic resin film of the present invention Although the tan resin is not particularly limited, an example of the use of a water-soluble or water-dispersible resin is a resin containing a block type isocyanate group, preferably a terminal isocyanate group. These are heat-reactive water-soluble urethanes that are blocked with hydrophilic groups (hereinafter also referred to as blocks). Blocking agents for blocking the isocyanate groups with hydrophilic groups include bisulfites and sulfonic acid group-containing phenols, alcohols, ratatas, oximes, and active methylene compounds. Can be mentioned. The blocked isocyanate group hydrophilizes the urethane prepolymer, and makes it water soluble. When heat energy is applied to the polyurethane resin during the drying or heat setting process during film production, the polyurethane resin deviates from the blocking agent strength isocyanate group. While fixing the copolymerized polyester resin, it also reacts with the terminal groups of the copolymerized polyester resin. The resin used during preparation of the coating solution is poor in water resistance due to its hydrophilicity.However, when the thermal reaction is completed after coating, drying and heat setting, the hydrophilic group of the urethane resin, that is, the blocking agent, is released. A coating film with good properties can be obtained. Among the above blocking agents, bisulfites are most preferred from the viewpoint that the blocking agent is removed from the isocyanate group at the heat treatment temperature and heat treatment time in the film production process, and that it is industrially available.

[0072] The chemical composition of the urethane prepolymer used in the above-mentioned resin includes (1) an organic polyisocyanate having two or more active hydrogen atoms in the molecule, or at least two in the molecule. A compound having an active hydrogen atom and a molecular weight of 200 to 20,000, (2) an organic polyisocyanate having two or more isocyanate groups in the molecule, or (3) at least two active hydrogen atoms in the molecule A compound having a terminal isocyanate group obtained by reacting a chain extender having

[0073] The compounds of (1) above are generally known because they contain two or more hydroxyl groups, carboxyl groups, amino groups or mercapto groups at the terminal or in the molecule. Examples of the compound include polyether polyol, polyester polyol, and polyether ester polyol. Examples of polyether polyols include compounds obtained by polymerizing alkylene oxides such as ethylene oxide and propylene oxide, styrene oxide, epichlorohydrin, and the like, or random copolymerization or polymerization of two or more thereof. There are compounds obtained by lock copolymerization or compounds obtained by addition polymerization of these with polyhydric alcohols.

[0074] Examples of the polyester polyol and the polyether ester polyol include mainly linear or branched compounds. Polyvalent saturated or unsaturated carboxylic acids such as succinic acid, adipic acid, phthalic acid, and maleic anhydride, or anhydrides of these carboxylic acids, ethylene glycol, diethylene glycol, 1,4 butanediol, neopentyl glycol, Of polyvalent saturated or unsaturated alcohols such as 1,6 hexanediol and trimethylolpropane, relatively low molecular weight polyethylene glycols, polyalkylene ether glycols such as polypropylene glycol, or alcohols thereof. It can be obtained by condensing the mixture.

[0075] Further, as the polyester polyol, a polyester capable of obtaining ratatones and hydroxy acids can be used, and as the polyether ester polyol, ethylene oxide or propylene oxide or the like can be used for the polyester prepared by force. Added polyester esters can also be used.

[0076] The organic polyisocyanate of (2) above includes isomers of toluylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, and aromatics such as xylylene diisocyanate. Alicyclic diisocyanates such as aliphatic diisocyanates, isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and 2,2,4 trimethylhexamethylene diisocyanate Aliphatic diisocyanates such as sulfonates, or polyisocyanates obtained by adding these compounds together with trimethylolpropane or the like in a single or plural number

And the like.

[0077] The chain extender having at least two active hydrogens in (3) above includes glycols such as ethylene glycol, diethylene glycol, 1,4 butanediol, and 1,6 hexanediol; glycerin, trimethylolpropane And polyhydric alcohols such as pentaerythritol; diamines such as ethylenediamine, hexamethylenediamine and piperazine; amino alcohols such as monoethanolamine and diethanolamine; thiodiglycol such as thiojetylene dalcol Or water. [0078] In order to synthesize urethane prepolymers, usually, by a single-stage or multi-stage isocyanate polyaddition method using the above chain extender, at a temperature of 150 ° C or lower, preferably 70 to 120 ° C, 5 React for minutes to several hours. If the molar ratio of isocyanate groups to active hydrogen atoms is 1 or more, it is necessary that free isocyanate groups remain in the urethane prepolymer obtained. Furthermore, the content of the free isocyanate group may be 10% by mass or less, but considering the stability of the urethane polymer aqueous solution after being blocked, it is preferably 7% by mass or less.

[0079] The urethane prepolymer obtained is blocked using the blocking agent (preferably bisulfite). Mix with the aqueous blocking agent solution and allow the reaction to proceed for approximately 5 minutes to 1 hour without stirring well. The reaction temperature is preferably 60 ° C or lower. Thereafter, it is diluted with water to an appropriate concentration to obtain a heat-reactive water-soluble urethane composition. The composition is prepared to an appropriate concentration and viscosity when used, but when heated to about 80-200 ° C, the blocking agent is dissociated and the active isocyanate group is regenerated. Polyurethane polymers are formed by polyaddition reactions that take place internally or intermolecularly, and have the property of causing addition to other functional groups.

[0080] As an example of the heat-reactive water-soluble urethane described above, "Elastron (registered trademark)" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. is typically exemplified. Elastrone is a block of isocyanate group with sodium bisulfite, and there is a strong rubamoyl sulfonate group with strong hydrophilicity at the molecular end.

RU

[0081] The resin component used in the coating layer of the laminated thermoplastic resin film of the present invention is an acrylic resin used for forming a diffusion layer, prism lens, and hard coat layer, from the viewpoint of adhesion to various inks. It is preferable to use a copolymerized polyester resin and a polyurethane-based resin together. The copolyester resin alone has sufficient adhesion to the polyester base film. The prism lens may be inferior in adhesion to the acrylic resin used in the nanocoat, and the copolyester Since rosin is relatively brittle, it is prone to cohesive failure due to impact during cutting. On the other hand, polyurethane resin alone has relatively good adhesion to hard coat layer, diffusion layer, and acrylate resin, poor adhesion to polyester base film, and blocking resistance. Inferior. [0082] When the copolymerized polyester resin and the polyurethane-based resin are used in combination, the blending ratio can be selected as appropriate. For example, when a coating liquid is prepared by mixing the copolymerized polyester resin and the polyurethane resin used in the present invention, the copolymerized polyester resin (referred to as (A)) and the polyurethane resin (referred to as (B)). ) Is preferably (A) :( B) = 7: 3-3: 7, more preferably 6: 4-4: 6. If the mass ratio of the solid content of the copolyester resin is larger than the above range, the coating layer becomes brittle, and it can withstand high-speed cutting in the processing process after forming the acrylate hard coat layer or diffusion layer. In some cases, cannot be obtained. If the solid content mass ratio of the copolymerized polyester resin is smaller than the above range, the coating property, adhesion and blocking resistance to the thermoplastic resin film as the substrate may be lowered, which is not preferable. A preferred embodiment of the coating solution will be described in the manufacturing method.

(Particles) By incorporating particles into the coating layer and forming appropriate irregularities on the surface of the coating layer, slipping property, winding property, and scratch resistance are imparted. For this reason, it is possible to maintain high transparency that does not require the inclusion of particles in the substrate.

[0084] As particles, particles having high affinity with copolymerized polyester resin or polyurethane-based resin are preferred, and there is a difference that the affinity for both is unevenly distributed in either phase. preferable. By making the particles unevenly distributed on one of the phase-separated greaves, the particles can be gathered properly, and by adding relatively few particles, that is, without significantly increasing haze, excellent blocking resistance can be obtained. It can be done.

[0085] Particles to be included in the coating layer include calcium carbonate, calcium phosphate, amorphous silica, crystalline glass filler, kaolin, talc, titanium dioxide, alumina, silica-alumina composite oxide particles, barium sulfate, fluoride. Inorganic particles such as calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, My power; cross-linked polystyrene particles, cross-linked acrylic resin particles, cross-linked methyl methacrylate particles, benzoguanamine 'formaldehyde condensate particles, melamine' formaldehyde condensate And heat-resistant polymer particles such as polytetrafluoroethylene particles.

Among these particles, particles made of silicon oxide (particularly silica particles) are preferable from the following points. The first advantage is that the resin component of the coating layer is relatively close to the refractive index, so that a highly transparent film is used. It is easy to get an film. The second advantage is that the particles tend to be unevenly distributed in the phase-separated polyurethane-based resin phase, and the polyurethane-based resin phase existing on the surface of the coating layer is inferior in blocking resistance. It is a point that can complement the nature of. This is thought to be because the surface energy of the particles and polyurethane-based resin is closer to that of copolymer polyester resin, and the affinity is higher.

[0087] Further, the shape of the particles is not particularly limited, but from the viewpoint of imparting easy slipperiness, particles having a nearly spherical shape are preferable.

[0088] The content of the particles in the coating layer is preferably 20% by mass or less based on the coating layer, more preferably 15% by mass or less, and particularly preferably 10% by mass or less. When the content of the particles in the coating layer exceeds 20% by mass, the transparency is deteriorated and the adhesion of the film tends to be insufficient. On the other hand, the lower limit of the content of particles is preferably 0.1% by mass, more preferably 1% by mass, and particularly preferably 3% by mass with respect to the coating layer.

[0089] Further, two or more kinds of particles having different average particle diameters may be contained in the coating layer. Further, the same kind of particles having different average particle diameters may be contained. In any case, the average particle size and the total content of the particles may be within the above ranges.

[0090] The average particle size of the particles is usually preferably 20 to 150 nm force S, more preferably 40 to 60 nm. If the average particle size is less than 20 nm, it is difficult to obtain sufficient blocking resistance, and scratch resistance tends to deteriorate. On the other hand, if the average particle size of the particles exceeds 150 nm, the haze increases and the particles easily fall off.

[0091] However, in the present invention, sufficient blocking resistance and scratch resistance may not be obtained with only the particles P1 having an average particle diameter of 20 to 150 nm. Therefore, in order to further improve the blocking resistance and scratch resistance, it is preferable to use a small amount of particles P2 having a larger average particle size. The average particle size of particles P2 having a large average particle size is preferably 160 to 1000 nm, particularly preferably 200 to 800 nm. When the average particle size of the particle P2 is less than 160 nm, scratch resistance, slipping property and winding property may be deteriorated. On the other hand, when the average particle size of the particles P2 exceeds lOOOnm, the haze tends to increase. In addition, it is preferable that the particle P2 is an aggregate particle in which primary particles are aggregated. In this case, the average particle diameter is considered as the average particle diameter of the aggregate particles. Furthermore, in this case, the average particle size of the aggregate particles and the primary particles A ratio of average particle diameters of 4 or more is also preferable in terms of scratch resistance.

[0092] When two types of particles are used, for example, the content ratio (P1ZP2) of particles P1 (average particle size: 20 to 150 nm) and particles P2 (average particle size: 160 to 1000 nm) in the coating layer is 5 to 30 In addition, the content of the particles P2 is 0.1 to 1% by mass with respect to the solid content of the coating layer. Controlling the content of the two types of specific particle sizes within the above range optimizes the three-dimensional center plane average surface roughness of the coating layer surface, and achieves both transparency and handling resistance as well as blocking resistance. Suitable for above. When the content of the particles P2 exceeds 1% by mass with respect to the coating layer, the haze tends to increase remarkably.

[0093] The average particle diameter of the particles is measured by the following method. Take a picture of the particles with an electron microscope, measure the maximum diameter of 300-500 particles at a magnification such that the size of one of the smallest particles is 2-5 mm, and use the average value as the average particle size. . In addition, when determining the average particle size of the particles in the coating layer of the laminated film, a cross section of the laminated film is photographed at a magnification of 120,000 using a transmission electron microscope (TEM), and exists in the cross section of the coating layer. The maximum diameter of particles can be measured. When particle P2 is an aggregate particle, the average particle size is 300 to 500 images of the cross-section of the coating layer of the laminated film at a magnification of 200 using an optical microscope. taking measurement.

[0094] (Foreign matter) In conventional laminated thermoplastic resin films, optical defects due to foreign matters with a small occurrence frequency but a major axis of 0.3 mm or more, which cannot be excluded only by filtration treatment of the coating liquid for producing the film. The cause of this optical defect was unknown. And the foreign component was also unknown. However, the present inventors have found that the cause of this optical defect is that the resin component contained in the coating solution (particularly the low molecular weight of the copolyester resin resin) is contained in the doctor blade of the coating apparatus for producing the film. Component) and particles, and in some cases, solids containing metal components are deposited, and when these solids reach a certain amount or more, the doctor blade force also falls off, which passes through the coater roll. Or, they thought that they were directly attached to the base film, and at the same time, they came up with the components of foreign matter.

Therefore, it is essential that the foreign matter referred to in the present invention is mainly composed of a coating layer resin component and particles. As a result, impurities removed by filtration such as dust, Distinguishable from foreign matter that only agglomerates are powerful.

[0096] The coating layer resin component means a copolymerized polyester resin used in the above coating layer (when used alone) or a copolymerized polyester resin and a polyurethane-based resin (when used together). In particular, it refers to the low molecular weight component of copolymer polyester resin. The particle is a particle used for the coating layer.

[0097] Further, the foreign matter referred to in the present invention includes a coating layer resin component and a particle component, and in some cases, as other components, a metal oxide or metal water produced from a copolymerization polyester polymerization catalyst. Contains metal components such as oxides.

[0098] The major axis of the foreign material is 0.3 mm or more. Here, the major axis is the maximum when the cross section of the foreign material is taken and the distance between any two points on the outer periphery of the cross section of the foreign material is measured. The distance between the two points.

[0099] The laminated thermoplastic resin film roll of the present invention preferably contains 30 ZlOOm ² or less of a foreign substance mainly composed of a coating layer resin component and particles having a major axis of 0.3 mm or more. is the foreign object 20 or ZlOOm ² or less, more preferably those containing 10 ZlOOm ² below. Most preferably, no such foreign matter is present in the film roll.

[0100] Laminated thermoplastic resin film roll force of the present invention When used for an optical substrate film such as a lens film or a diffusion plate, it is usually used even for a relatively thick film having a film thickness of 100 / zm or more. At least 1000m or more, sometimes 2000m or more of film length is used for the prism layer and diffusion layer lamination process. Obedience

Therefore, in the present invention, in consideration of the fact that the film roll is long, when the roll length of the film roll exceeds 1500 m, “30 foreign substances mainly composed of the coating layer resin component and particles” ^{For `} ` Contain ² or less '', remove the film for 100 m in the longitudinal direction of the film roll from the part where the coating layer was formed last (the part where the coating solution for coating layer formation was applied last), and then When measuring 7 points for every 100 m ^2, the maximum number of foreign substances with a major axis of 0.3 mm or more whose major component is a resin component and particles of the coating layer out of 7 points should be 30 or less ZlOOm ² . In the coating process for forming the coating layer, as the time passes, the solid matter mainly containing the resin component and particles contained in the coating liquid accumulates on the doctor blade. Foreign matter is generated It is because it is easy to produce.

[0101] In the present invention, the coating layer has a catalyst (inorganic substance, salt, organic substance, alkaline substance, acidic substance, metal-containing organic compound, etc.), antistatic agent, ultraviolet ray, as long as the effects of the present invention are not hindered. Various additives such as absorbents, plasticizers, pigments, organic fillers and moist particles may be contained.

[0102] The haze of the laminated thermoplastic resin film roll of the present invention is 1.5% or less. When used as a base film of an optical functional film or a sheet that requires a high degree of transparency, is important. The haze is more preferably 1.0% or less. When the haze exceeds 1.5%, it is not preferable because the sharpness of the screen is lowered when the film is used for a lens film for LCD or a substrate film for backlight. In order to reduce the haze of the laminated thermoplastic resin film of the present invention to 1.5% or less, it is preferable that no particles are contained in the base film (not compounded).

[0103] When the laminated thermoplastic resin film roll of the present invention is used for a substrate for an optical functional film or sheet, the three-dimensional center plane average surface roughness (SRa) of the coating layer surface of the film is: It is preferably as smooth as 0.002 to 0.01 μm. The upper limit of SRa is more preferably 0.0008 / z m force of transparency, and more preferably 0.0006 / z m. On the other hand, the lower limit of SRa is more preferably 0.0025 / z m force S and particularly preferably 0.0030 / z m from the viewpoint of handling properties such as slipping and winding properties and scratch resistance. A smooth surface with a SRa force of less than 0.002 μm of the coating layer is not preferable because blocking resistance, handling properties such as slipping and winding properties, and scratch resistance are reduced. On the other hand, when SRa of the coating layer exceeds 0.01 m, haze increases and transparency deteriorates, so that it is preferable as an optical functional film or a base film for a sheet!

[0104] The film thickness of the laminated thermoplastic resin film roll of the present invention is preferably a force 30.2 to 30.2 / zm force, and more preferably 50.2 to 250. . A film thickness of less than 30 is not preferable because the rigidity is insufficient. On the other hand, if the film thickness exceeds 300., there is a high possibility that foreign matter which is an optical defect present in the film will increase and the cost will be increased, which is not preferable.

[0105] The thickness of the coating layer is 0.005 to 0.2111, more preferably 0.008 to 0.15. μm. The thickness of the coating layer can be measured by cutting the cross section of the coating layer with a microtome and observing with an electron microscope. However, if the coating layer is soft, it may be deformed during cutting. For simplicity, if the coating amount is known, the density force of the coating layer can also be converted into a thickness. For example, if the coating layer density is lgZcm ³ and the coating amount is lgZm ² , the thickness corresponds to 1 μm. The density of the coating layer is determined by calculating the density of each material from the types of the resin and particles that make up the coating layer, multiplying the density of each material by the mass ratio of the material, and calculating the sum of the density. Can be estimated.

[0106] The winding length and width of the laminated thermoplastic resin film roll of the present invention are appropriately determined depending on the use of the film roll. The roll length of the film roll is preferably 1500 m or more, more preferably 1800 m or more. Further, the upper limit of the winding length is preferably 5000 m. Further, the width of the film roll is preferably 0.5 m or more, more preferably 0.8 m. The upper limit of the film roll width is preferably 2. Om.

[0107] The laminated thermoplastic resin film roll of the present invention is usually wound around a winding core, but there are no particular restrictions on the diameter and material of the winding core. Inches, 8-inch paper cores, plastic and metal cores can be used.

(Manufacturing method) [0108] Coated polyester resin or coating liquid containing a resin component and particles containing copolymer polyester resin and polyurethane resin is applied to one or both sides of a traveling thermoplastic resin film. A coating step, a drying step for drying the coating layer, a stretching step for stretching in at least a uniaxial direction, and a heat fixing processing step for heat-fixing the stretched coating film. The copolyester resin used for preparation is a solution of copolyester resin resin with a filtration particle size of 0.5 μm or more and 10 μm or less under the conditions of a liquid temperature of 15 ° C or higher and lower than 35 ° C. After filtering with a filter and heating to 50 ° C or higher and lower than 70 ° C, the size of the filtered particles is further reduced to 15 μC or higher and lower than 35 ° C. Those obtained by filtering with a filter of The production method constitutes a part of the present invention (hereinafter, the production method is also referred to as the production method of the present invention).

[0109] The production of a laminated thermoplastic resin film having excellent adhesion and few optical defects as defined in the present invention is performed by simply filtering the coating solution prepared for forming a coating layer. It is not possible to achieve this by simply reducing aggregates and foreign substances in the coating solution.By preparing a highly accurate refining process for the copolymerized polyester resin as a raw material when preparing the coating solution, Achieved for the first time.

[0110] (Coating process) [0110] The coating process is preferably carried out by an in-line coating method applied during the production process of the film. Alternatively, a coating solution containing the above-mentioned copolymerized polyester resin and the above-described polyurethane-based resin and the above-mentioned particles is continuously applied. It is more preferable to apply to the base film before the crystal orientation is completed. Examples of the coating method include a reverse roll-coating method, a gravure-coating method, a kiss-coating method, and an offset coating method, and these methods can be performed alone or in combination. These coating methods have a mechanism for scraping off excess coating liquid on the roll with a doctor blade, and are suitable for obtaining a uniform coated surface with little coating unevenness. In the present invention, it is preferable to use the reverse kiss roll / coating method in terms of surface quality.

[0111] In the present invention, the coating solution for forming the coating layer is preferably an aqueous coating solution from the viewpoints of the environment and safety. Therefore, the copolymerized polyester resin and the polyurethane-based resin used in the present invention are preferably water-soluble or water-dispersible.

[0112] The coating solution is obtained by dispersing or dissolving the resin in a solvent with stirring, and then adding particles, surfactants and various additives as necessary, and diluting to a desired solid content concentration. To prepare.

[0113] In the present invention, the solvent used in the coating solution broadly includes a dispersion medium used to disperse the resin in the form of particles in addition to the liquid that dissolves the resin. Various solvents such as a solvent can be used, and an aqueous solvent is preferable for the above viewpoint.

[0114] The solvent used in the coating solution is preferably a solvent prepared by mixing water and alcohols such as ethanol, isopropyl alcohol, and benzyl alcohol in a range of 30 to 50% by mass in the total coating solution. In addition, when the mixing amount of the alcohol is less than 10% by mass, an organic solvent other than the alcohol may be mixed in a range in which it can be dissolved. However, the total amount of alcohols and other organic solvents in the coating solution should be less than 50% by mass. Alcohol mixing amount (If other organic solvents are used, alcohol and the organic solvent If the total amount of the agent is less than 50% by mass, the drying property is improved during coating and drying, and the appearance of the coating layer is improved as compared with the case of water alone. When the addition amount of the organic solvent is 50% by mass or more based on the total solvent, the solid matter tends to be deposited on the doctor blade. In addition, the evaporation rate of the solvent is increased, and the concentration of the coating solution is likely to change during coating. As a result, the viscosity of the coating solution increases and the coatability decreases, which may cause a poor appearance of the coating film. Furthermore, due to the volatilization of organic solvents, there is a high risk of fire. In addition, when the amount of the organic solvent added is less than 30% by mass with respect to the total solvent, bubbles tend to be mixed into the coating solution, and as a result, streaky defects tend to occur on the coated surface, which is preferable. . In the present invention, it is preferable that the lance of the mixed solvent concentration is not greatly changed during the coating process.

[0115] In preparing the coating solution, a copolymer polyester resin having a low content of low molecular weight components is used. In order to reduce the content of the low molecular weight components of the copolymer polyester resin, In the above-described method, that is, a copolymerized polyester resin is dissolved in a solvent to prepare a solution, and the solution is filtered at a liquid temperature of 15 ° C or higher and lower than 35 ° C. After filtering with a filter of μm or more and 10m or less, and then heating to 50 ° C or more and less than 70 ° C, the filter particle size is more than 0. The resulting filtrate may be used as it is for coating solution preparation, using a method of filtration through a filter of 10 m or less.

[0116] When adding the particles to the liquid being prepared, it is preferable to add the particles to water or an organic solvent in advance as a dispersion having a concentration of 2% by mass or more and less than 25% by mass. When particles are added directly to the liquid being prepared, uniform dispersion becomes difficult, and as a result, the particle aggregates become the core, and the precipitation of solid matter on the doctor blade increases. When preparing a dispersion of particles, it is preferable to sufficiently disperse using a stirrer. Examples of the stirrer include a powder dissolver (TK homojitter M type), and dispersion conditions are 5000 rpm or more, preferably lOOOO rpm or more, stirring time 30 minutes or more, preferably 60 minutes or more with respect to 10 kg of the dispersion. is there.

[0117] When the aqueous coating solution is applied to the substrate film surface, it is preferable to use a surfactant in order to improve wettability to the film and to apply the coating solution uniformly. Surface activity The type of the agent is not particularly limited as long as good coating properties can be obtained, and nonionic surfactants, cationic surfactants, and the like can be suitably used. A fluorosurfactant is particularly suitable for obtaining coating properties. The addition amount of the surfactant can be appropriately selected as long as it does not impair the adhesion of the hard coat layer and the diffusion layer and can provide good coating properties. It is preferable to add 18% by mass, more preferably 0.02-0.1% by mass. If the amount added is less than 0.01% by mass, good coating properties may not be obtained. If the amount added exceeds 0.1% by mass, the particles contained in the coating solution tend to agglomerate. The frequency of occurrence may increase. In the case of a fluorinated surfactant, it is preferably 30 times or less from the critical micelle concentration with respect to pure water. If the critical micelle concentration is 30 times or more, the particles contained in the coating solution tend to aggregate, leading to the occurrence of coating streaks and leading to an increase in the haze of the resulting laminated film, particularly as an optical substrate film. Is not preferred. In addition, the surfactant component may bleed out and adversely affect adhesion. Less than the critical micelle concentration is preferable because good coatability may not be obtained.

[0118] In order to adjust the pH of the coating solution, an alkaline substance or an acidic substance may be added as a pH adjuster. Adhesiveness and blocking resistance as pH adjuster

It is not particularly limited as long as it does not adversely affect the coating properties and coating properties, or the effect is negligible, but examples include sodium bicarbonate, sodium carbonate when raising the pH, and acetic acid when lowering. It is done. The preferred pH of the coating solution of the present invention is preferably in the range of 4 or more and less than 8. If the pH is less than 4, the copolyester component tends to segregate on the surface of the coating layer, and sufficient adhesion to the hard coat layer in the hard coat film, the diffusion layer in the diffusion plate, and the prism layer in the prism sheet cannot be obtained. There are cases. A pH of 8 or more is not preferable because aggregation tends to occur depending on the type of particles and haze increases.

[0119] A catalyst may be added to the coating solution to promote the thermal crosslinking reaction. For example, various chemical substances such as inorganic substances, salts, organic substances, alkaline substances, acidic substances and metal-containing organic compounds. Is used for the catalyst.

[0120] Further, the coating solution has an antistatic agent and UV absorption as long as it does not lose easy adhesion. Various additives such as additives, plasticizers, antibacterial agents, photooxidation catalysts, pigments, organic fillers and lubricants may be mixed.

[0121] The solid content concentration in the coating solution is preferably 30% by mass or less, and particularly preferably 10% by mass or less. The lower limit of the solid content concentration is preferably 1% by mass, more preferably 3% by mass, and particularly preferably 5% by mass.

[0122] The coating liquid is preferably subjected to microfiltration in order to uniformly disperse the resin component and particles of the coating liquid and to remove foreign matters such as coarse particle aggregates and dust in the process. The filter medium for microfiltration of the coating liquid is preferably a filter medium having a filtration particle size (initial filtration efficiency: 95%) of 25 μm or less, more preferably a filtration performance of 10 m or less. Most preferred is a method in which filters having different filtration performance are used in combination. When a filter medium with a filter particle size exceeding 25 m is used, removal of coarse aggregates tends to be insufficient. For this reason, coarse agglomerates that cannot be removed by filtration spread due to the stretching stress in the uniaxial or biaxial stretching process after coating and drying, and are recognized as agglomerates of 100 m or more, causing optical defects. Cheap. However, if the filtration performance is 0.5 μm or less, even the necessary particle agglomerates are removed and the originally required slipperiness and anti-blocking properties may be lowered, which is not preferable. Practically, the lower limit of the filter filtration particle size of the coating solution is 5 m, but it is not necessary for the coating solution as soon as it retains slipperiness and blocking resistance with less frequent filter clogging. It is also preferable not to apply a shearing force to. The type of filter medium for finely filtering the coating solution is not particularly limited as long as it has the above performance, and examples thereof include a filament type, a felt type, and a mesh type. The material of the filter medium for finely filtering the coating liquid is not particularly limited as long as it has the above-mentioned performance and does not adversely affect the coating liquid. Examples thereof include stainless steel, polyethylene, polypropylene, and nylon.

[0123] The method for coating the coating layer in the present invention is not particularly limited as long as it is the above-mentioned method, but the coating liquid is formed by bringing the substrate film into contact with the applicator roll in various arrangements such as horizontal or vertical. A method of transferring the coating solution on the applicator roll to the substrate film with a meniscus is preferable. Particularly in the production of laminated films for optical applications, a slight amount of liquid that occurs downstream of the tangent line between the traveling substrate film and the applicator roll. In order to quickly remove bubbles contained in the reservoir, the method of running the substrate film vertically as shown in Fig. 1 is preferred. Further, the method of running the base film in the vertical direction is preferable because it is easy to apply both surfaces simultaneously.

[0124] In order to describe the production method of the present invention in detail, a reverse kiss coating method will be described as an example. As shown in Fig. 1, the reverse kiss coating method uses an applicator roll 2 and a metering roll 3 that rotate in the reverse direction of the film travel direction, and the applicator roll 2 is brought into contact with the traveling film 1 to apply the coating liquid. It is a method of applying by transferring to the film 1

[0125] As shown in Fig. 2, the coating liquid tank for supplying the coating liquid to the coater is divided into a tank 9 for the preparation and a tank 11 for the circulation having a smaller capacity than the tank 9 for the preparation. It is preferable to circulate the coating solution only between the coater and the coater. If the circulation tank 11 is not provided, when the amount of liquid in the tank decreases due to consumption of the coating liquid, the number of times the coating liquid circulates between coaters increases and the balance of the solvent tends to fluctuate. This is not preferable because coarse aggregates of particles are likely to be generated. On the other hand, increasing the capacity of the circulation tank 11 relative to the capacity of the saucer 7 is effective in stabilizing the mixed solvent concentration balance. Specifically, the capacity of the saucer 7 for the coating liquid is set to 1. Sometimes, the ratio of the capacity of the circulation tank 11 is 1:10 or more, preferably 1:50 or more. If the capacity of the circulation tank 11 is smaller than 1:10, the fluctuation of the mixed solvent concentration balance becomes large, which is not preferable immediately. More preferably, the ratio of the capacity of the circulation tank 11 to the capacity of the blending tank 9 is 1:10 or more, preferably 1:20 or more. At this time, it is preferable to supply the coating liquid from the preparation tank 9 to the circulation tank 11 so that the capacity of the circulation tank 11 is always constant during operation.

[0126] Defoaming is preferably performed in order to prevent the generation of coating streaks due to bubbles in the coating solution.

Defoaming is performed, for example, by means for preventing air from being entrained in the coating liquid as much as possible and means for removing air in the coating liquid present in a minute amount.

[0127] The means to prevent air from being entrained in the coating liquid as much as possible is that the coating liquid force scraped by the doctor blade 6 from the Fountain die 4 and the metalling roll 3 directly falls onto the tray 7 and air is mixed by this impact. As shown in Fig. 1, the guide plate 5 is installed on the fanten die 4 and the doctor blade 6 and the coating liquid force is applied along the guide plate 5 as shown in Fig. 1. This is a means that smoothly flows into the tray 7. In addition, the means for removing a small amount of air in the coating solution is a cooling device that extends upward as shown in FIG. 2 in the middle of the pipe for supplying the coating solution from the circulation tank 11 to the foam die 4. A branch pipe 10 having a not-shown) is provided, and this pipe force is means for removing air contained in the coating solution. By controlling the temperature of the outlet of this branch pipe 10 to 20 ° C or less, preferably 10 ° C or less with a cooling device, volatilization of a highly volatile solvent can be suppressed, and the mixed solvent balance of the coating solution can be reduced. The change can be reduced. It is more preferable that the height of the outlet of the branch pipe 10 is at least 10 cm or more than the liquid surface of the veg application liquid circulation tank to prevent the outflow of the application liquid and to obtain a sufficient cooling effect. Is 20cm or more. As a liquid degassing method, air may be removed by degassing under reduced pressure. However, the present invention is not preferable because the balance of the mixed solvent tends to be lost.

[0128] In particular, when water and isopropyl alcohol are used as the mixed solvent, the balance of the mixed solvent in which isopropyl alcohol is higher in evaporation rate than water is likely to be lost. It is preferable to take measures to stabilize the mixed solvent concentration balance. As a specific example of measures to stabilize the mixed solvent concentration balance, a solvent volatilization prevention cover 8 is provided on the apparatus including the applicator roll 2, the metering roll 3, and the coating liquid tray 7 as shown in FIG. It is effective to take measures to bring the inside of the prevention cover 8 close to the saturated vapor pressure of isopropyl alcohol. When the solvent volatilization prevention cover 8 is not provided, foreign matter tends to increase when the roll length exceeds 1000 m. Although it is difficult to seal completely due to the structure, the stability of the solvent concentration balance of the coating solution on the applicator roll 3 is greatly improved by reducing the opening. The mixed solvent concentration balance measure is not limited to the above.

[0129] The temperature of the coating solution supplied to the fountain die 4 and the surface temperatures of the applicator roll 2 and the metering roll 3 are preferably 10 ° C or higher and lower than 30 ° C. When the temperature of the coating solution is 30 ° C or higher, it is preferable that the coating solution easily deteriorates! /. If it is less than 10 ° C, the viscosity of the coating solution becomes high and uneasiness tends to occur. In addition, it is preferable to obtain a uniform quality that the difference between the temperatures does not exceed 10 ° C. If the surface temperature of applicator roll 2 and metering roll 3 is 30 ° C or higher, especially The surface becomes easy to dry, and as a result, solid matter is often deposited on the doctor blade 6.

[0130] The force at which the applicator roll 2 is brought into contact with the traveling film 1 and the coating solution is transferred to the film 1. The film traveling speed is not particularly limited, but it is preferably 10mZ to 100mZ. 20mZ Minutes to 80mZ are more preferred. If it is less than 10 mZ, the productivity is lowered and the manufacturing cost is increased. If it exceeds lOOmZ, it becomes easy for air bubbles to be mixed into the coating solution, and the coating spots are easily generated.

[0131] In the reverse coating method, the applicator roll 2 rotates in the reverse direction with respect to the film traveling direction. The peripheral speed of the applicator roll is a ratio of the film traveling speed (F) to the peripheral speed (A) of the applicator roll ( (Hereinafter referred to as the AZF ratio) 1.00-1.30 is preferred 1.02: L20 is more preferred. If the AZF ratio is less than 1.00, transfer failure of the coating liquid tends to occur, and if it exceeds 1.30, coating spots are likely to occur.

[0132] In the reverse coating method, it is preferable that the roll diameter is 10 cm to 50 cm for both the applicator roll 2 and the metal ring 3. The diameter ratio of the 2Z metal ring 3 is in the range of 0.5 to 2. Preferably there is.

[0133] At the time of application, as described above, when the roll dries, solids are deposited on the doctor blade 6. Therefore, it is important to prevent the roll from drying. Further, the generation of the doctor blade force is suppressed. Therefore, the roll to be used is subjected to a hard chrome plating treatment, and

It is preferable to use a mirror-coated roll having a surface roughness of 0.3 S or less. This surface roughness is more preferably 0.2S or less, more preferably 0.1S or less. 0. If 3S is exceeded, doctor blade debris is likely to occur.

[0134] The lower limit of the contact pressure of the doctor blade 6 to the metering roll 3 is usually 20 gfZcm (0.

20 NZcm), preferably 30 gfZcm (0.29 NZcm), and the upper limit is usually 100 gfZcm (0.98 NZcm), preferably 80 gfZcm (0.78 NZcm). If it is less than 20 gfZcm (0.20 N / cm), the effect of removing the coating solution on the metering roll 3 is insufficient, and as a result, coating spots are likely to occur. On the other hand, if it exceeds 100 gfZcm (0.998 NZcm), solids are likely to precipitate on the doctor blade 6, which is not preferable.

[0135] The doctor blade 6 is made of polyethylene, polyester, polyacetal, etc. It may be made of metal such as stainless steel or Swedish steel, or ceramic. However, polishing is performed after the slit, and high straightness is preferred.

[0136] Further, by improving the accuracy (roundness and cylindricity) of the roll of the coating apparatus, the contact pressure between the doctor blade 6 and the roll 3 in contact with the doctor blade 6 can be stabilized. This is effective in reducing the precipitation of solids. In the present invention, by improving the roll accuracy (roundness and cylindricity) with currently available technology, it is possible to minimize variations in the coating thickness in the length direction. (Roundness and cylindricity) is preferably 5 ZlOOOmm or less. The roundness related to roll accuracy here is the difference between the radii of two concentric circles by the minimum area method determined using a recorded roundness measuring instrument as shown in J IS B 0621. Expressed in units of mm. In addition, the cylindricity is measured in various measurement planes over the entire length while moving the stand with a measuring instrument with the roll placed on the surface plate in the axial direction and placing the probe on the top surface of the cylinder. And the maximum difference in reading at that time is represented by 1Z2.

The unit is mm.

[0137] The coating amount when the coating solution is undried (hereinafter abbreviated as wet coating amount) is preferably ² gZm ² or more and less than lOgZm 2. If the wet coating amount is less than ² gZm ² and the final coating layer coating amount of the design (the solid content mass per unit area of the film after drying and before stretching) is obtained, the solid content concentration of the coating solution is increased. There is a need. When the solid content concentration of the coating solution is increased, the viscosity of the coating solution is increased, so that streaky coating spots are likely to occur. On the other hand, when the wet coating amount is lOgZm ² or more, coating spots are easily generated due to the influence of drying air in the drying furnace. Also, it is preferable to manage the final coating layer coating amount (solid mass per unit area of the film after drying and before stretching) at 0.005-0. 2 g / m ² , more preferably 0. . manage to 008~ 0. 15gZm ^2. If the coating amount is less than 0.005 gZm ^2, it is difficult to obtain sufficient adhesion. In order to prevent defects due to dust adhesion, it is preferable to apply the coating solution in a clean environment with a cleanness of class 5000 or less. The film coated with the coating solution of the coating amount is guided to a tenter for orientation and heat setting, and is heated there to form a stable film by a thermal crosslinking reaction, thereby forming a laminated thermoplastic resin film. .

[0138] Also, the film tension during coating should be 4,000 to 10,000 NZ original fabric width (original fabric width is 1 to 2m) If the film tension is within this range, the flatness of the film is maintained on an industrial scale (the tension varies depending on the thickness of the film and is relatively thin! The flatness is maintained at the same time), and the local contact between the applicator roll and the substrate film can be prevented, and the transfer amount of the coating solution can be made uniform in the length direction of the film. If the width exceeds 10000 NZ, the original film will be deformed, resulting in locally high contact pressure between the applicator roll and the base film, and scratches will be generated. Even when the width is less than 4000NZ, the flatness of the film during coating becomes insufficient, and scratches due to local contact between the applicator roll and the base film are likely to occur, and the film may meander. Furthermore, the transfer amount of the coating liquid becomes non-uniform along the length of the film. In addition, the variation in the wet coating amount of the film is not preferable because the variation in the thickness of the coating film is further increased.

[0139] As a means for improving the flatness of the film during coating, a method of sandwiching both surfaces with a pair of pinch rolls at both ends in the width direction of the film between the coater and the drying furnace is also effective.

(Drying process) [0140] In the drying process after coating, it is preferable to dry in the drying furnace for 0.1 to 5 seconds while maintaining the temperature at 120 ° C or higher and lower than 150 ° C. The drying time is more preferably 0.5 to 3 seconds. When the drying time is less than 0.1 second, the coating film is not sufficiently dried, and the roll is applied with insufficient drying when passing through the roll arranged before the transverse stretching process. There is a tendency to be contaminated on the surface. On the other hand, if the drying time exceeds 5 seconds, the base film tends to crystallize and the frequency of breakage during transverse stretching increases.

[0141] After drying the coating film at a temperature of 120 ° C or more and less than 150 ° C in the drying furnace, it is preferable to immediately cool the laminated film having the coating layer to near room temperature. When the laminated film leaves the drying oven with the surface temperature of 100 ° C. or higher and the laminated film comes into contact with a roll near room temperature, scratches are likely to occur due to film shrinkage.

[0142] It is preferable to use air purified with a HEPA filter in order to prevent dust from the dry wind power from entering the drying furnace. The HEPA filter used at this time should be a filter that has the ability to cut 95% or more of dust with a nominal filtration accuracy of 0.5 m or more. Is preferred.

[0143] The drying and cooling conditions in the drying process are the so-called drying zones of about 1 to 8 stages in which the temperature and time conditions of the furnace are sequentially changed (in practice, from the drying zone and the cooling zone). It is an embodiment of a proper drying method to employ multi-stage drying of preferably 3 to 6 stages. Each stage (zone) in the drying process is determined at the manufacturing site in consideration of conditions such as the concentration of the dispersion, the coating amount, the traveling speed of the coated traveling film, the temperature of the hot air, the wind speed, and the amount of air. Appropriate values can be determined as appropriate.

[0144] As an example, the following method is suitable when the coating solution is applied to one or both sides of a uniaxially oriented thermoplastic resin film and dried in a multi-stage drying furnace disposed immediately above the coater.

[0145] For example, when drying in four stages, drying is performed in a drying furnace divided into four drying zones. Specifically, in the first drying zone, the temperature is 125 to 140 ° C for 0.1 to 4 seconds, in the second drying zone, the temperature is 55 to 100 ° C for 0.1 to 4 seconds, in the third drying zone. A method of drying at a temperature of 35 to 55 ° C. for 0.1 to 4 seconds and in a fourth drying zone at a temperature of 25 to 35 ° C. for 0.1 to 4 seconds can be mentioned.

[0146] The numerical range of the drying conditions varies slightly depending on the solid content concentration of the coating solution, and is not limited to this setting example. However, the air flow for drying is also varied at each stage. It's important to. By way of example of air volume, in the first drying zone,. 20 to 50MZ sec air velocity of the drying air, the supply air volume of the drying air 100-150 ³ Z seconds, setting the exhaust air volume to 150 to 200 m ³ Z seconds. For the second drying zone, the supply air volume is set to 60 to 140 m ³ Z seconds and the exhaust air volume to 100 to 180 m ³ Z seconds until the fourth drying zone. In any drying zone, set so that drying air does not flow to the coater side.

[0147] (Drawing process) After drying, the end of the film is gripped with a clip, and usually heated to 80 to 180 ° C (preferably 100 to 140 ° C), and the wind speed is 10 to 20mZ seconds. Lead to hot air zone and stretch 2-6 times in width direction (preferably 2.5-5.0 times). Further, stretching may be performed in another direction.

[0148] (Heat setting process) Subsequently, heat of usually 220 to 240 ° C, preferably 225 ° C to 235 ° C Lead to the treatment zone and heat treatment is usually performed for 1 to 20 seconds to complete crystal orientation. If it is less than 220 ° C, the heat shrinkage rate of the obtained laminated film becomes large, which is not preferable. If it exceeds 240 ° C, the adhesion to the hard coat layer or the diffusion layer may decrease. During this process, apply a 1-12% relaxation treatment in the width or longitudinal direction as necessary.

[0149] In general, the transverse stretching process, the heat setting process, and the cooling process are divided into 10 to 30 zones for the purpose of uniforming the temperature, and the temperature is controlled in each zone! In particular, in the latter half of the transverse stretching zone and in the heat setting maximum temperature setting zone, it is preferable to raise the temperature stepwise and make the temperature uniform in order to obtain a film having a uniform heat shrinkage rate in the width direction.

[0150] Laminated film force obtained by squeezing is rolled by a conventional method with a winder or the like, whereby the laminated thermoplastic resin film roll of the present invention is produced. The film tool may be cut into an appropriate width by a slitter or the like.

[0151] The obtained laminated thermoplastic resin film roll-out film is also excellent in easy adhesion, has excellent optical properties, and has few coating streaks. It can be suitably used as a base film for film and a base film for AR (anti-reflection) film.

Example

[0152] Next, the method for producing a laminated thermoplastic resin film of the present invention will be described by taking a polyethylene terephthalate (hereinafter abbreviated as PET) base material as an example, but the present invention is of course not limited thereto. . In the examples, the evaluation of characteristics was performed by the following method.

(1) Defect detection method Product film roll force obtained in Examples and Comparative Examples [0153] A sample film roll having a width of lm and a length of 100 m was hung in the vertical direction in the tub chamber. At this time, 100 m of the surface layer of the product film roll was removed, and the subsequent 100 m was used as a sample. Next, place a non-glossy black cloth on the entire back surface of the film with V ヽ, and use a prom light (VIDEO LIGHT VLG301 100V 300W LPL) from the front surface (covering layer surface) to unwind the laminated film and roll the film surface. observed from the film front while changing the angles of the bromine lights in the range of approximately 10 ° of 45 ° relative to, the major axis 0. 3 mm or more evaluation area 100 m ² The above optical defects were detected and marked using a scaled magnifier (PEAK SCALE LUPE X 10) with a magnification of 10 times (Evaluation area was 100 m even if the width of the product film roll was less than lm) ² !)). Further, use a brush (KOKUYONE TZ-4021N) to lightly wipe the defective part and confirm that there is no dust adhesion, and then use a Kimwipe impregnated with methyl ethyl ketone (WIPRS S200: manufactured by Crecia). The defect part was rubbed and the number of defects that disappeared was determined to be the number of defects per 100 m ² (the solvent in this case is not particularly limited as long as it can dissolve the coating layer). Also, when measuring 7 points in length of 100m each in the length direction of the film, after unwinding from a film roll with a winding length of 1500m or more, remove the 100m portion, take a 100m sample, and continuously 7 film samples with a length of 100 m were taken, and the number of optical defects with a major axis of 0.3 mm or more was counted for each sample, and the maximum number of defects was counted as the maximum number of defects per 100 m ² in a film roll with a length of 1500 m. It was. (Even if the width of the product film roll is less than lm, the evaluation area of each sample may be 10 Om ² )

Example 1 (1) Preparation of Coating Solution A coating solution used in the present invention was prepared according to the following method. A reactor is charged with 95 parts by weight of dimethyl terephthalate, 95 parts by weight of dimethyl isophthalate, 35 parts by weight of ethylene glycol, 145 parts by weight of neopentyl glycol, 0.1 part by weight of zinc acetate and 0.1 part by weight of antimony trioxide. The transesterification was carried out at ° C for 3 hours. Next, 6.0 parts by mass of 5 sodium sulfoisophthalic acid was added, the esterification reaction was carried out at 240 ° C for 1 hour, and then at 250 ° C under reduced pressure (10 to 0.2 mmHg) for 2 hours. The polycondensation reaction was carried out to obtain a copolymerized polyester resin (A) having a number average molecular weight of 19,500 and a softening point of 60 ° C. The obtained 30% by mass aqueous dispersion of copolymerized polyester resin (A) was allowed to stand for 10 days, and about 9/10 of the supernatant was taken out and subjected to coating liquid preparation. This aqueous dispersion of copolymer polyester resin (A) is filtered through a felt type filter with a filtration particle size of 5 μm under the condition of a liquid temperature of 25 ° C until the number of circulation is 5 (filtration step 1 1 and Further, filtration was performed with a felt type filter having a filtration particle size of 1 μm until the number of circulation was 30 times (denoted as filtration step 1-2). Next, after heating to 60 ° C and holding for 2 hours, filter with a felt type filter with a filtration particle size of 1 μm at 25 ° C until the number of circulation reaches 5 (referred to as filtration step 2). )did. [0155] A self-crosslinked polyurethane-based resin containing 7.5 parts by mass of an aqueous dispersion of the copolymerized polyester resin (A) obtained by the above treatment and an isocyanate group blocked with sodium bisulfite ( B) 20 mass% aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Elastron (registered trademark) H-3) 11.3 parts by mass, elastotron catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat64) 0.3 mass parts, water 39.8 parts by mass and 37.4 parts by mass of isopropyl alcohol were mixed. Further, colloidal silica (manufactured by Nissan Kagaku Kogyo Co., Ltd.) as 0.6 parts by mass of a 10% by mass aqueous solution of a fluorine-based non-ionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFace (registered trademark) F142D) , SNOWTEX (registered trademark) OL; 20 mass% aqueous dispersion of average particle size 40 nm) 2.3 parts by weight, dry process silica as particles P2 (manufactured by Nippon Aerosil, Aerosil (registered trademark) OX50; average particle size 200 nm) Average primary particle size 40nm)

0.5 parts by mass of a 5% by mass aqueous dispersion was added. When preparing a 3.5% by mass aqueous dispersion of the particles P2, 10 kg of the dispersion was stirred with a powder dissolver (T. K. Homogeneter M type) at a rotation speed of lOOOOrpm for 60 minutes. Next, the pH of the coating solution was adjusted to 6.2 with 5% by weight aqueous sodium bicarbonate solution to prepare coating solution A.

(2) Production of laminated polyester film [0156] Polyethylene terephthalate resin pellets containing no particles and having an intrinsic viscosity of 0.62 dlZg as a raw polymer were dried under reduced pressure (135. 3 Pa) at 135 ° C for 6 hours. . Next, the polyethylene terephthalate resin pellets after drying are supplied to an extruder, melt-extruded into a sheet at about 285 ° C, and rapidly cooled and solidified on a metal roll maintained at a surface temperature of 20 ° C. Obtained. In addition, filtration is performed during melt extrusion, but for filtration, the filter particle size (initial filtration efficiency: 95%) is a stainless steel sintered material with a force of 15 m. A filter medium was used.

[0157] The obtained cast film was heated to 95 ° C with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a difference in peripheral speed, and a uniaxially oriented PET film. Got. Next, the coating solution A was filtered through a felt type filter having a filtration performance of 10 m (filtration step 3), and applied to one side of a uniaxially oriented PET film running at a speed of 40 mZ by the reverse roll method. After that, in a drying furnace divided into four zones located just above the coater, the first zone temperature 135 ° C, 1.0 second, the second zone temperature 65 ° C, 2.2 seconds, the third zone temperature 40 The coated surface was dried at ° C for 1.8 seconds and the fourth zone temperature at 30 ° C for 1.8 seconds. Ma The coating amount was set to 0.08 gZm ² as the final solid content.

[0158] The coating conditions at this time were as follows. (A) 22 ° C for both applicator roll and metering roll (b) Temperature of coating solution supplied to fountain die: 23 ° C (c) Contact pressure of doctor blade against metallizing roll: 30gfZcm (0.29N / cm )

[0159] Further, in this coating, a coating apparatus having the following characteristics was used. (A) Use an applicator roll with a solvent volatilization prevention cover in the applicator including the applicator roll, metering roll, and coating solution pan. (B) Applicator roll diameter φ250mm, Metalling roll diameter φ220mm (C) Applicator roll and Roundness of ring roll: 3 / 1000mm (D) Surface roughness of applicator roll and metering roll: 0. IS (E) Doctor blade: Material SUS402 Thickness 0.075mm, Width 50mm (Miller Graphics, (Product name Echo Blade) (F) Capacitance ratio of coating liquid and circulation tank = 1: 50 (G) Capacity ratio of circulation tank and preparation tank = 1:40

[0160] Subsequently, while holding the edge of the film with a clip, the film was guided to a hot air zone at a temperature of 120 ° C and stretched 4.3 times in the width direction. Next, the first heat fixing zone (temperature: 200 ° C), the second heat setting zone (temperature: 210 ° C), the third heat setting zone (temperature: 220 ° C), 4th heat setting zone (temperature: 230 ° C), 5th heat setting zone (temperature: 210 ° C) 6th heat setting zone (temperature: 170 ° C, 3% relaxation treatment in the width direction) ) After passing through the seventh heat setting zone (temperature: 120 ° C.) successively, the film was coated on both ends, trimmed, and wound up with a winder. This was further divided into four equal parts in the width direction and slitted to obtain a laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 m.

[0161] (Example 2) Compared to the formulation of Example 1, the standing period of the 30% by weight aqueous dispersion of copolymer polyester resin (A) was changed from 10 days to 5 days, and coating solution B It was. A laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating solution B was used.

[0162] (Example 3) In comparison with the formulation of Example 1, the 30% by weight aqueous dispersion of copolymerized polyester resin (A) was not subjected to the filtration treatment before the heating treatment (filtration step 1 2). The coating solution was C. Except for using coating solution C, the same method as in Example 1, with a width of lm, a film length of 1500 m, and a thickness of 125 A μm laminated polyester film roll was obtained.

[0163] (Example 4) Compared to the formulation of Example 1, the filtration accuracy of the filtration treatment (filtration step 2) after the 30% by weight aqueous dispersion of copolymerized polyester resin (A) was heated. The thickness was changed from 1 μm to 5 μm and used as coating solution D. A laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 m was obtained in the same manner as in Example 1 except that the coating solution D was used.

[0164] (Example 5) Compared to the formulation of Example 1, the heating temperature of the 30% by weight aqueous dispersion of copolymer polyester resin (A) was changed from 60 ° C to 55 ° C and coated. Liquid E was designated. A laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating solution E was used.

(Example 6) [0165] Compared to the formulation of Example 1, the heating time of the 30% by weight aqueous dispersion of copolymer polyester resin (A) was changed from 2 hours to 1 hour, and coating solution F It was. A laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating solution F was used.

(Example 7) In the preparation of the coating liquid of Example 1, 44.5 parts by mass of water and 32.8 parts by mass of isopropyl alcohol were used as coating liquid G. A laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating solution G was used.

(Example 8) [0167] In the preparation of the coating liquid of Example 1, 35.1 parts by mass of water and 42.1 parts by mass of isopropyl alcohol were used as coating liquid H. A laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating liquid H was used.

(Example 9) [0168] In Example 1, except that the mass ratio of the copolymerized polyester resin and the polyurethane resin in the coating solution was changed to the following coating solution I, which was changed to 60Z40. In the same manner as in 1, a laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained.

(Preparation of coating liquid I) In the preparation of the coating liquid of Example 1, it was allowed to stand in the same manner as in Example 1, filtration treatment 1 1, filtration treatment 1 2, heating treatment, and filtration treatment 2. Polyurethane used in Example 1, 9.0 parts by mass of a 30% by mass aqueous dispersion of the copolymer polyester resin (A). 9.0 parts by mass of a 20% by mass aqueous solution of the system resin (B), 0.3 parts by mass of an elastolone catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat64), 40.6 parts by mass of water, and 37 parts of isopropyl alcohol . 3 parts by weight of each were mixed. Furthermore, 0.6 part by mass of the surfactant aqueous solution used in Example 1 and a 20% by mass aqueous dispersion of colloidal silica (Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles P1 were 2.3. 0.5 parts by mass of a 3.5% by mass aqueous dispersion of dry silica (Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as part P2 is added as the particle P2, and 5 mass The pH was adjusted with an aqueous solution of sodium bicarbonate to make coating solution I.

[Example 10] [0170] In Example 1, the following application was carried out except that the mass ratio of the copolymerized polyester resin to the polyurethane resin in the coating solution was changed to 40Z60. In the same manner as in Example 1, a laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained.

[Coating! ¾ [Preparation] In the preparation of the coating liquid of Example 1, the sample was left standing in the same manner as in Example 1, filtration treatment 1 1, filtration treatment 1 2, heating treatment, and filtration treatment 2. 6.0 parts by mass of a 30% by mass aqueous dispersion of the copolymer polyester resin (A) and 13.5 parts by mass of a 20% by mass aqueous solution of the polyurethane-based resin (B) used in Example 1, The catalyst for use (Daiichi Kogyo Seiyaku Co., Ltd., Cat64) 0.3 parts by mass, water 38.9 parts by mass, and isopropyl alcohol 37.5 parts by mass were mixed. Furthermore, 0.6% by mass of a 10% by mass aqueous solution of the surfactant used in Example 1 and 20% by mass aqueous dispersion of colloidal silica (Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A Add 0.5 parts by weight of a 3.5% by weight aqueous dispersion of 2.3 parts by weight of the liquid and dry process as particles B (manufactured by Nippon Aerosil Co., Ltd., Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm). Adjust the pH to 6.2 with a 5% by weight aqueous sodium bicarbonate solution and apply! ¾ [Assessed.

(Example 11) [0172] The surface roughness of the applicator roll and metering roll was 0.3S. The same method as in Example 1 was used except that the coating apparatus was used. The width lm, the film length 1500m, and the thickness A 125 m laminated polyester film roll was obtained.

Example 12 A width lm and a film length of 1500 were obtained in the same manner as in Example 1 except that the applicator roll and the metering roll had a roundness of 6Zl000 mm. A laminated polyester film roll having a thickness of m and a thickness of 125 m was obtained.

Example 13 A width lm, a film length of 1500 m, and a thickness of 1 25 were obtained in the same manner as in Example 1 except that the contact pressure of the doctor blade to the metering roll was changed to 60 gfZcm (0.59 NZcm). A μm laminated polyester film roll was obtained.

[0175] (Example 14) The surface temperature of the applicator roll and the metering roll, and the temperature of the coating solution supplied to the foundation die were set to 17 ° C in the same manner as in Example 1 except that the width was 1 m. A laminated polyester film roll having a film length of 1500 m and a thickness of 125 μm was obtained.

(Example 15) [0176] In Example 1, a preparation tank was not used separately from the circulation tank, and the coating liquid was prepared in the circulation tank and re-prepared when the coating liquid ran out. In the same manner as in Example 1, a laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 μm was obtained.

[0177] (Comparative Example 1) In Example 1, the standing period of the 30% by mass aqueous dispersion of copolymer polyester resin (A) was set to 1 day, and filtration steps 1 and 2 and A laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 m was obtained in the same manner as in Example 1 except that the heating process was not performed and a different coating apparatus and method described below were used. . Coating equipment (Α ') No application of solvent volatilization prevention cover to application equipment including applicator roll, metering roll and coating liquid tray (i) Application without using a tank for preparation separately from the circulation tank The solution was prepared in a circulation tank and re-prepared when the coating solution was exhausted. (I) In the filtration step 3, a felt type filter having a filtration particle size of 3 m was used.

[0178] (Comparative Example 2) In Comparative Example 1, the same method as in Example 1 except that the filtration particle size of the felt type filter in the filtration step 3 was changed to 1 µm, the width lm and the film length 1500m. A laminated polyester film roll having a thickness of 125 m was obtained.

[0179] (Comparative Example 3) In the preparation of the coating solution, the standing period was 1 day, the filtration treatment 1 1, the filtration treatment 1

-2, Heat treatment, and Filtration treatment 2 榭 Copolymer polyester resin (A) 30 mass% aqueous dispersion of 7.5 parts by mass, polyurethane resin (B ) 20% aqueous solution, 11.3 parts by mass, elastron catalyst (Daiichi Kogyo Seiyaku: Cat 64) 0.3 parts by mass, water 40.5 parts by mass and isopropyl alcohol 39.5 parts by mass Each part was mixed with a 10% by weight aqueous solution of a fluorocarbon-based surfactant (Megafac F142D). A coating liquid L was prepared by adding 0.03 parts by mass of a 3.5 mass% aqueous dispersion of mass parts, particles C (manufactured by Fuji Silysia Chemical Co., Ltd .: Silicia 310, average particle size 1.4 m). The pH was not adjusted and the pH was 4.6. Next, the dried polyethylene terephthalate resin pellets were fed to an extruder in the same manner as in Example 1, and melt-extruded into a sheet at about 285 ° C.

A cast film was obtained by rapid cooling and solidification on a metal roll maintained at a surface temperature of 20 ° C. At this time, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency of 95%) of 15 m was used as a filter medium for removing foreign substances from the molten resin. Next, as in Example 1, this cast film was heated to 95 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a difference in peripheral speed. A uniaxially oriented PET film was obtained. Next, the coating solution is microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency 95%) (filtration step 3), and applied to one side of a uniaxially oriented PET film by the reverse roll method. It was led to a drying furnace and dried at 120 ° C for 3.2 seconds. The coating amount was set to 0.08 gZm ² as the solid content. At this time, the wind speed in the first zone of the drying furnace is 15mZs, the second zone force is the same as in Example 1, and the supply air volume of the drying air is 70m ^{3 in} both the first zone and the fourth zone. / s.

[0180] The coating conditions and the coating apparatus were the same as in Example 1 except for the following points. (A〃) The solvent volatilization prevention bar was not provided in the coating apparatus including the applicator roll, the metering roll, and the coating liquid tray. (D ') Surface roughness of applicator roll and metering roll: 0.3S (H') Do not use a tank for blending separately from the tank for circulation. Prepare the coating liquid in the tank for circulation. Re-prepared when there was no more. (1 ′) In the filtration step 3, a felt type filter having a filtration particle size of 25 μm was used.

[0181] Subsequently, a laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 m was obtained in the same manner as in Example 1 except that the transverse draw ratio was 4.0.

[0182] (Comparative Example 4) Example 1 except that the coating liquid M was used in Example 1 except that the 30% by weight aqueous dispersion of the copolymer polyester resin (A) was not heated. In the same manner as in Example 1, a laminated polyester film roll having a width of lm, a film length of 1500 m, and a thickness of 125 m was obtained.

[0183] The conditions for producing film rolls and evaluation results for each Example and each Comparative Example are summarized in Tables 1 to 3 below. [0184] [Table 1]

[0185] [Table 2]

s [] ^ 0186w

Industrial applicability

The laminated thermoplastic resin film roll of the present invention is mainly used for display-related applications, such as an antireflection film, a light diffusion sheet, a prism sheet, an infrared absorption film, an electromagnetic wave shielding film, a transparent conductive film, and an antiglare film. It is suitable as a substrate film for producing various optical functional films.

Claims

The scope of the claims

[1] A coating layer comprising a thermoplastic resin film as a base material, a resin component containing a copolymerized polyester resin or a copolymerized polyester resin and a polyurethane-based resin on at least one surface of the base material, and particles A roll-like product of a laminated film provided with a coating layer, wherein the content of foreign matter having a major axis of 0.3 mm or more whose major component is a coating resin component and particles is 30/100 m ² or less. Laminated thermoplastic resin film roll.

[2] The film roll according to [1], wherein the winding length is 1500 m or more and the width is 0.5 m or more.

[3] The particles contained in the coating layer are particles having an oxy-silicon power.

The laminated thermoplastic resin film roll according to 1 or 2.

[4] The laminated thermoplastic resin film roll according to any one of claims 1 to 3, wherein the thermoplastic resin film substrate substantially does not contain particles.

[5] The laminated thermoplastic resin final resin according to any one of claims 1 to 4, wherein the copolymer polyester resin is a copolymer polyester resin having a low content of low molecular weight components.

[6] Copolyester resin is filtered through a filter of copolymer polyester resin with a filter particle size of not less than 0 and not more than 10 m under conditions of liquid temperature of 15 ° C or more and less than 35 ° C. After heating to 50 ° C or more and less than 70 ° C, filter with a filter with a particle size of 0.5 μm or more and 10 μm or less under conditions of 15 ° C or more and less than 35 ° C. 6. The laminated thermoplastic resin film roll according to claim 5, wherein the laminated thermoplastic resin film roll is obtained by purification.

[7] A coating process in which a coating liquid containing a coagulated polyester resin or a copolyester resin and a polyurethane resin is applied to one or both sides of a traveling thermoplastic resin film, In a method for producing a laminated thermoplastic resin film roll formed by a drying process for drying a coating layer, a stretching process for stretching in at least a uniaxial direction, and a thermosetting process for thermosetting the stretched coating film. The copolymer polyester resin is filtered through a filter having a filter particle size of not less than 0 and not more than 10 m under the conditions of a liquid temperature of 15 ° C or more and less than 35 ° C. After heating to 50 ° C or more and less than 70 ° C, filter with a filter with a particle size of 0.5 μm or more and 10 μm or less under conditions of 15 ° C or more and less than 35 ° C. Obtained by processing What is claimed is: 1. A method for producing a laminated thermoplastic resin film roll, comprising:

[8] A coating process in which a coating liquid containing a coagulated polyester resin or a copolyester resin and a polyurethane resin is applied to one or both sides of a traveling thermoplastic resin film, A drying step for drying the coating layer, a stretching step for stretching in at least a uniaxial direction, and a heat setting treatment step for heat-setting the stretched coating film, wherein the copolymer polyester resin is a solution of the copolymer polyester resin Is filtered through a filter with a particle size of 0. or more and 10 m or less under the conditions of a liquid temperature of 15 ° C or more and less than 35 ° C, and further heated to 50 ° C or more and less than 70 ° C. It is obtained by filtering through a filter having a filtration particle size of 0.5 μm or more and 10 μm or less under conditions of 15 ° C or more and less than 35 ° C. Laminated thermoplastic according to any one of 1 to 5 Method of manufacturing a 榭脂 film roll.

[9] The process according to claim 8, which is carried out by a reverse roll coating method, a gravure coating method, a kiss coating method, an offset coating method, or a combination of these methods.

[10] The application process according to claim 8 or 9, wherein an application roll and a metalling roll having a surface roughness of 0.1 S or less and a roundness of 5 Zl000 mm or less are used in the coating process in the coating process. Production method.