JP2007055222A - Laminated thermoplastic resin film and laminated thermoplastic resin film roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated thermoplastic resin film excellent in adhesion and blocking resistance. <P>SOLUTION: The laminated thermoplastic resin film has a coated layer containing a copolymerized polyester-based resin and a polyurethane-based resin on one or both of the sides of a polyester film. The coated layer has a structure in which PEs phases A mainly composed of a copolymerized PEs-based resin and PU phases B mainly composed of a PV-based resin are separated as micro phases or nano phases. Under scanning phase microscopic observation in phase measurement mode on a measured area of 5 μm×5 μm, the ratio of the surface (PEs surface ratio) of the PEs phase A (a dark phase 1 in a phase image) on the surface of the coated layer as defined by formula (1) is more than 35% and under 90%. Formula (1) is [PEs surface ratio (%)]=(area of PEs phase A/measured area)×100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  Various functional layers (hard coat layer, light diffusion layer, prism, etc.) such as an antireflection film, a light diffusion sheet, a prism sheet, an infrared absorption film, a transparent conductive film, and an antiglare film, which are mainly used in display-related applications. Layer, infrared absorption layer, transparent conductive layer, anti-glare layer, etc.), a unique phase that is a base material for optical functional films or optical functional sheets, and has excellent blocking resistance and transparency. The present invention relates to a laminated thermoplastic resin film in which a coating layer having a separation structure is formed, and a laminated thermoplastic resin film roll formed by winding the laminated thermoplastic resin film into a roll.

  In general, base materials for optical functional films used for display members such as liquid crystal displays (LCD) and plasma display panels (PDP) include polyethylene terephthalate (PET), acrylic, polycarbonate (PC), and triacetyl cellulose (TAC). ), A transparent film made of polyolefin or the like is used. When these base films are used for various optical functional films, functional layers corresponding to various uses are laminated on the base film. For example, in a liquid crystal display (LCD), a protective film (hard coat layer) that prevents scratches on the surface, an antireflection layer (AR layer) that prevents reflection of external light, and a prism layer that is used to collect and diffuse light And a functional layer such as a light diffusion layer for improving luminance. Among these substrates, in particular, biaxially oriented polyester films are widely used as substrates for various optical functional films from the viewpoints of excellent transparency, dimensional stability, and chemical resistance.

  In general, 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 that it can adhere to various paints, adhesives, inks, etc. There is a disadvantage of being scarce. For this reason, methods for imparting easy adhesion to the biaxially oriented thermoplastic resin film surface by various methods have been proposed.

  Films that do not have polar groups, such as polyolefin films, have very poor adhesion to various paints, adhesives, inks, etc., so physical and chemical treatments such as corona discharge treatment and flame treatment are performed beforehand. After being performed, methods for imparting easy adhesion to the film surface by various methods have been proposed.

  For example, on the surface of the thermoplastic resin film of the base material, various resins such as polyester, acrylic, polyurethane, and acrylic graft polyester are the main constituent components of the coating layer, and by providing the coating layer on the base film by a coating method, A method for imparting easy adhesion to a base film is generally known. Among these coating methods, a thermoplastic resin film before completion of crystal orientation is subjected to corona discharge treatment directly or as necessary, and then a dispersion in which the resin solution or resin is dispersed with a dispersion medium is contained. A water-based coating solution is applied to a base film, dried, stretched at least in a uniaxial direction, and then subjected to heat treatment to complete the crystal orientation of the thermoplastic resin film (so-called in-line coating method) After manufacturing a plastic resin film, a method (so-called off-line coating method) in which an aqueous or solvent-based coating solution is applied to the film and then dried (so-called off-line coating method) has been widely practiced industrially.

  LCDs, PDPs, and other displays have been increasing in size and cost year by year, and production speeds have been increased in the manufacturing process of optical functional films or optical functional sheets used as members thereof. As the manufacturing process is speeded up, stress due to curing shrinkage is more likely to occur at the interface between the functional layer such as the hard coat layer, the diffusion layer, and the prism layer and the base film. Therefore, when cutting an optical functional film or an optical functional sheet to a specific size for manufacturing a display, the problem is that the end portion is particularly easily peeled off when the adhesion at the interface is insufficient. Happened. The tendency of this tendency is that the larger the film wound up in rolls and the higher the production speed in the manufacturing process, the more the influence of the peeling of the interface due to the impact during cutting becomes more pronounced. Is becoming insufficient.

  Furthermore, the processing agent used for forming the functional layers such as the prism layer and the diffusion layer is applied directly to the base film without being diluted with an organic solvent from the viewpoint of reducing the environmental load. There are many cases. Therefore, since the wettability improvement effect of the coating layer by an organic solvent may not be obtained sufficiently, higher adhesion is required. On the other hand, in applications such as hard coat where importance is placed on smoothness, the processing agent is often diluted with an organic solvent in order to lower the viscosity of the processing agent and obtain a good leveling effect. In this case, the coating layer of the laminated thermoplastic resin film is required to have appropriate solvent resistance.

  In order to improve the adhesion between the functional layer and the substrate film, a method of using a resin having a low glass transition temperature as the resin constituting the coating layer is common. However, when a resin having a low glass transition temperature is used, the blocking resistance tends to decrease when the film is continuously wound into a roll and the film is unwound from the roll.

  In recent years, in order to reduce the cost, the size of a processing machine for laminating functional layers such as a hard coat layer and a diffusion layer on a base film has been increased, and a roll of an easily adhesive film used as a base film. The diameter is also increasing. Along with this, when winding with high tension in order to prevent roll misalignment, blocking is more likely to occur because the core of the roll is pressure-bonded with high pressure.

  In order to improve the blocking resistance, a method of providing irregularities on the film surface and reducing the contact area is generally employed. In order to give unevenness to the film surface, a method of increasing the content of inorganic particles or organic particles contained in the coating layer or the base film, or a method of using particles having a large particle size is common. However, the refractive index of commercially available particles is generally different from the refractive index of the resin used for the coating layer, and voids are formed around the particles as the film is stretched. This causes a decrease in the light transmittance of the film and an increase in haze. In particular, the transparency required for the optical functional film or the base film of the optical functional sheet is lowered. In other words, with conventional methods, it is extremely difficult to improve adhesion and blocking resistance with a functional layer while maintaining transparency due to new problems associated with higher process speeds and larger roll diameters of films. Met.

  On the other hand, opportunities for using information terminals outdoors, such as mobile phones, PDAs, and mobile computers, are increasing. In addition, materials used in cars that become hot in summer, such as touch panels used for car navigation, are increasing. Therefore, there is a demand for such applications for a film with little change in quality even under such a severe environment of high temperature and high humidity, that is, a film excellent in wet heat resistance.

In particular, it is known that a biaxially oriented polyester film has poor adhesion to a coating agent mainly composed of an acrylic resin used for prism lenses, hard coats, and the like. For this reason, various types in which a coating layer made of a polyurethane resin or the like is formed on the surface of a polyester film have been proposed (see, for example, Patent Document 1). However, when a coating layer made of polyurethane resin is formed, the adhesion with a functional layer such as a hard coat layer is improved, but the adhesion with a polyester film as a substrate is not sufficient, resulting in coating. There was a problem that the adhesion was insufficient at the interface between the layer and the functional layer. In addition, since the degree of cross-linking of the resin constituting the coating layer is low and the heat- and heat-resistant adhesion is poor, there is a case where the above market demand cannot be sufficiently satisfied in applications where moisture and heat-resistant adhesion is strongly desired.
JP-A-6-340049

In addition, a resin composition layer mainly comprising a polyester resin and a polyurethane resin is provided on a base film made of biaxially oriented polyethylene terephthalate by an inline coating method, and a functional layer such as a base polyester film and an ink There has been proposed a method for improving the adhesion (see, for example, Patent Document 2). Specifically, a water-dispersible coating solution containing a copolymerized polyester resin and a polyurethane resin (= 20/80; mass%) is applied to a polyester film that is uniaxially stretched in the longitudinal direction, and then guided to a tenter and dried. After transverse stretching, the film was heat-set at 220 ° C. to obtain an easily adhesive biaxially oriented polyester film.
Japanese Patent Publication No. 64-6025

  However, in the method described in Patent Document 2, although the adhesion is improved, in recent years, a base film, a hard coat layer, and a diffusion layer, which are required as a base film used for an optical functional film or an optical functional sheet, are used. Such as adhesion to functional layers, blocking resistance and transparency could not be satisfied at the same time. In addition, since the degree of cross-linking of the resin constituting the coating layer is low and the heat- and heat-resistant adhesion is poor, there is a case where the above market demand cannot be sufficiently satisfied in applications where moisture and heat-resistant adhesion is strongly desired.

  The present applicant provides a resin composition layer in which a polyester resin, a polyurethane resin, and inorganic particles having an appropriate particle diameter are added on a base film made of biaxially oriented polyethylene terephthalate. A laminated polyester film that can sufficiently satisfy the required level of adhesion from the market while maintaining transparency, which is an extremely important property as a film, has been proposed (for example, Patent Document 3). 4). Specifically, a polyester film stretched uniaxially in the longitudinal direction, a copolymer polyester resin, a polyurethane resin (= 20/80; mass%), two types of silica particles having different average particle sizes, an anionic surface activity An easy-adhesive biaxially oriented polyester film obtained by applying a water-dispersible coating solution containing an agent to a tenter, drying, transverse stretching, and heat setting at 240 ° C. was disclosed.

The easy-adhesive biaxially oriented polyester film obtained in Patent Documents 3 and 4 has excellent adhesion and blocking resistance, transparency, and optical defects such as foreign matter and scratches are greatly improved. It satisfied the conventionally required characteristics. However, as mentioned above, with the recent cost reduction and display enlargement, the base film, hard coat layer, and diffusion required as optical functional films or base films for optical functional sheets The required level of adhesion to functional layers such as layers and prism layers, and blocking resistance tends to be stricter year by year, and it is no longer sufficient to satisfy the required quality of the current market. In addition, since the degree of cross-linking of the resin constituting the coating layer is low and the heat- and heat-resistant adhesion is poor, there is a case where the above market demand cannot be sufficiently satisfied in applications where moisture and heat-resistant adhesion is strongly desired.
JP 2000-323271 A JP 2000-246855 A

In addition, the present applicant has proposed an invention relating to an easy-adhesive film roll in which the variation in coating amount is reduced in order to improve the uniformity of adhesion (see, for example, Patent Document 5). In the example of Patent Document 5, a polyester film uniaxially stretched in the longitudinal direction, a polyester resin and a polyurethane resin (= 50/50; mass%), silica particles having an average particle diameter of 1.4 μm, and fluorine An easy-adhesive biaxially oriented polyester film obtained by applying a water-dispersible coating solution containing a surfactant, drying at 120 ° C. in a drying furnace, transversely stretching, and then heat-setting at 220 ° C. is described. Has been. The obtained film roll had excellent adhesion uniformly throughout the film roll, and satisfied the required level from the market. However, as described above, the anti-blocking property recently required is no longer satisfactory. In addition, since the degree of cross-linking of the resin constituting the coating layer is low and the heat- and heat-resistant adhesion is poor, there is a case where the above market demand cannot be sufficiently satisfied in applications where moisture and heat-resistant adhesion is strongly desired.
JP 2004-10669 A

Further, 100 parts by mass of a polyester in which the acid component is terephthalic acid / isophthalic acid / trimellitic acid / sebacic acid, and the glycol component is composed of ethylene glycol / neopentyl glycol / 1,4-butanediol, methylol-type melamine-based crosslinking A coating solution containing 15 parts by weight of the agent and 0.7 parts by weight of the particles is applied to a polyethylene terephthalate film uniaxially stretched in the longitudinal direction, and further subjected to transverse stretching, heat setting, and relaxation treatment. It is disclosed (for example, see Patent Document 6). However, although this method has improved wet heat resistance, it is inferior in initial adhesion with a functional layer such as a hard coat layer, and has not fully satisfied the quality required for recent optical films. .
JP 2004-299101 A

  In other words, with the conventional technology, while maintaining high transparency, it has become sufficiently unsatisfactory with respect to adhesion that can withstand high-speed cutting required in recent years and blocking resistance that can cope with an increase in film roll diameter. is there. Further, even in a severe environment of high temperature and high humidity, the adhesiveness is not sufficiently lowered, and the moisture and heat resistance is not sufficient.

  A first object of the present invention is to solve the above-mentioned conventional problems, and is to provide a laminated thermoplastic resin film that is highly excellent in adhesion and blocking resistance. The second object of the present invention is to provide a laminated thermoplastic resin film that is highly excellent in moisture and heat resistance in addition to adhesion and blocking resistance. A third object of the present invention is to provide a laminated thermoplastic resin film that is highly excellent in transparency in addition to adhesion and blocking resistance. Furthermore, a fourth object of the present invention is to provide a laminated thermoplastic resin film roll that is highly excellent in adhesion, blocking resistance, and wet heat resistance and has little fluctuation in quality.

The above-described problem can be achieved by the following solution means.
That is, the first invention in the laminated thermoplastic resin film of the present invention is a laminated thermoplastic resin film having a coating layer containing a copolymerized polyester resin and a polyurethane resin on one side or both sides of the thermoplastic resin film. ,
The coating layer has a structure obtained by microphase separation or nanophase separation into a polyester phase A mainly composed of a copolyester resin and a polyurethane phase B mainly composed of a polyurethane resin, and a scanning probe microscope. Is observed in the phase measurement mode, the area ratio (PEs surface fraction) of the polyester phase A (indicating a dark hue in the phase image) on the surface of the coating layer defined by the following formula (1) is 5 μm × 5 μm. It is a laminated thermoplastic resin film characterized by having a measurement area of 35% or more and less than 90%.
PEs surface fraction (%) = (Area of polyester phase A / Measurement area) × 100
... (1)

  A second invention is characterized in that the copolyester resin is crosslinked with at least one crosslinking agent selected from an epoxy crosslinking agent, a melamine crosslinking agent, and an oxazoline crosslinking agent. It is a lamination | stacking thermoplastic resin film of description.

  A third invention is the laminated thermoplastic resin film according to the first invention, wherein particles are contained in the thermoplastic resin film, or both the thermoplastic resin film and the coating layer.

  The fourth aspect of the invention is the laminated thermoplastic resin film according to the first aspect of the invention, wherein the thermoplastic resin film contains substantially no particles and contains particles only in the coating layer. It is.

  A fifth invention is the laminated thermoplastic resin film according to the third or fourth aspect, wherein the particles are silica particles.

  A sixth invention is the laminated thermoplastic resin film according to the third or fourth invention, wherein the particles in the coating layer are unevenly distributed in the polyester phase A or the polyurethane phase B.

  A seventh invention is the laminated thermoplastic resin film according to the first invention, wherein the thermoplastic resin film is a biaxially oriented polyester film or a biaxially oriented polyamide film.

  In an eighth aspect of the present invention, the surface of the coating layer is observed in a phase measurement mode of a scanning probe microscope, and a phase image in which the outline of the interface between the bright hue and the dark hue is emphasized, using a box counting method. 2. The laminated thermoplastic resin film according to claim 1, wherein a fractal dimension obtained from a boundary line (a contour of an interface) between a dark hue and a dark hue is 1.60 to 1.95 in a measurement area of 5 μm × 5 μm. It is.

A ninth invention is the laminated thermoplastic resin film according to the first invention, wherein the hardness index of the coating layer defined below is 3.0 to 15.0 nm.
The coating layer hardness index is a needle with a sapphire with a radius of 75 μm at the tip, and the surface of the coating layer is scratched by applying a weight of 5 gf. Means the average value of each measured value when 50 height differences between adjacent convex portions and concave portions are measured.
It is.

  A tenth invention is the laminated thermoplastic resin film according to the third or fourth invention, wherein the haze of the laminated thermoplastic resin film is 1.5% or less.

  An eleventh aspect of the invention is a laminated thermoplastic resin film according to the tenth aspect of the invention, which is used as a base film for an optical functional film or an optical functional sheet.

  In the twelfth invention, the optical functional film or the optical functional sheet is any one of a hard coat film, an antireflection film, a light diffusion sheet, a prism sheet, a transparent conductive film, a near-infrared absorbing film, and an electromagnetic wave absorbing film. The laminated thermoplastic resin film according to the eleventh aspect, wherein

  A thirteenth invention is the laminated thermoplastic resin film according to the first invention, wherein a functional layer containing an acrylic resin as a main constituent component is laminated on at least one surface of the coating layer. .

The fourteenth invention is the thermoplastic resin film according to any one of the first to thirteenth inventions, which has a coating layer containing a copolymerized polyester resin and a polyurethane resin on one side or both sides of a thermoplastic resin film. An area of a laminated thermoplastic resin film roll having a length of 1000 m or more and a width of 50 mm or more and continuously wound into a roll, and having an area of polyester phase A (showing a dark hue in a phase image) on the surface of the coating layer When the ratio (PEs surface fraction) is measured at 100 m intervals in the longitudinal direction of the film, the difference between the maximum value and the minimum value of the PEs surface fraction on the surface of the coating layer in the longitudinal direction is 15% or less. A laminated thermoplastic resin film roll.
In addition, the measurement of the PEs surface fraction in the surface of the said coating layer unwinds the said laminated thermoplastic resin film roll, and the end of the steady area where the film physical property is stable about the longitudinal direction (MD) of this film. When the first end and the other end are the second end, the first measurement is performed 2 m or less inside the first end, the final measurement is performed 2 m or less inside the second end, and 1 Every 100m from the first measurement point.

  In a fifteenth aspect of the invention, the laminated thermoplastic resin film roll is unwound, the film is divided into four equal parts in the width direction, and the polyester phase A on the surface of the coating layer (showing a dark hue in the phase image) at each central portion. In the fourteenth invention, the difference between the maximum value and the minimum value of the PEs surface fraction on the surface of the coating layer in the width direction is 10% or less when the area ratio (PEs surface fraction) is measured It is a lamination | stacking thermoplastic resin film roll of description.

  The laminated thermoplastic resin film of the present invention comprises two types of resins constituting the coating layer, that is, a copolymerized polyester-based resin and a polyurethane-based resin comprising a polyester phase A and a polyurethane-based resin whose main component is a copolymerized polyester-based resin. The polyurethane phase B as the main component has a specific microphase separation structure or nanophase separation structure, and the area ratio (PEs surface fraction) of the polyester phase A on the surface of the coating layer is in a specific range. It is excellent in adhesion and blocking resistance with functional layers such as a hard coat layer, a diffusion layer, and a prism layer.

  Further, in the coating layer, at least one of the above-mentioned copolymer polyester resins is cross-linked with at least one cross-linking agent selected from an epoxy-based cross-linking agent, a melamine-based cross-linking agent, and an oxazoline-based cross-linking agent, thereby improving wet heat resistance adhesion. be able to.

  Further, transparency can be improved by containing a specific amount of particles having a specific particle size only in the coating layer, or by making the particles unevenly distributed in either the polyester phase A or the polyurethane phase B on the surface of the coating layer. It is useful as a base film for optical functional films or optical functional sheets where transparency is highly required because it can improve blocking resistance, handling properties, and scratch resistance while maintaining a high level. . In particular, when silica particles are contained in the coating layer, silica particles can be unevenly distributed in the polyurethane phase, so that the disadvantage of polyurethane having poor blocking resistance can be compensated.

  In the present invention, definitions of adhesion, blocking resistance, transparency, and wet heat resistance described in the subject will be described first.

The adhesion referred to in the present invention means that a hard coat layer obtained by curing a solvent-diluted photocurable acrylic resin with ultraviolet rays is formed on the coating layer surface of the film, and a cross-cut peel test (100 pieces) using an adhesive tape for each. This means the adhesiveness at the interface between the acrylic hard coat layer and the coating layer of the film after repeating 10 times. In the present invention, the adhesiveness defined by the following formula is 80% or more. Preferably it is 85% or more, particularly preferably 90% or more.
Adhesiveness (%) = (1-number of cells peeled off / 100) × 100

In addition, the blocking resistance as used in the present invention refers to a method in which the coating layer surfaces of two film samples are overlapped and adhered to each other at a pressure of 1 kgf / cm ² for 24 hours in an atmosphere of 50 ° C. and 60% RH. , Peeled off, and the peeled state is “passable without peeling of coating layer”.

  Furthermore, the film having high transparency in the present invention means a film having a haze of 1.5% or less. Preferably, the haze is 1.0% or less.

The moisture and heat resistant adhesion referred to in the present invention is a solvent-free photocuring property using a film sample after storing a laminated thermoplastic resin film in an environment of a temperature of 60 ° C. and a relative humidity of 90% for 1000 hours. The acrylic hard coat layer and film after a hard coat layer obtained by curing an acrylic resin with ultraviolet rays is formed on the coating layer surface of the film and a cross-cut peel test (100 squares) using an adhesive tape is performed. Means the adhesiveness of the interface with the coating layer. In the present invention, the adhesiveness defined by the following formula is 71% or more.
Adhesiveness (%) = (1-number of cells peeled off / 100) × 100

  In the present invention, in order to obtain a laminated thermoplastic resin film having such excellent adhesion and blocking resistance, a specific microphase separation structure or nanophase separation structure can be expressed on the surface of the coating layer. is important. Such a specific phase separation structure is selective for the resin composition of the coating solution used for forming the coating layer, the type and concentration of the surfactant, the coating amount, the drying conditions of the coating layer, and the heat setting conditions. It can be formed by adopting and controlling them.

  Further, in order to obtain a laminated thermoplastic resin film having heat and moisture resistance, it is important to form a crosslinked structure in the resin constituting the coating layer. In addition, in order to form a crosslinked structure in the resin constituting the coating layer, the type and amount of the crosslinking agent and heat treatment conditions (curing conditions) are appropriately selected.

  First, the outline of the method for producing a laminated thermoplastic resin film of the present invention will be described using polyethylene terephthalate (hereinafter abbreviated as PET) as a representative example, but it is not limited to this representative example.

  PET pellets that do not substantially contain particles for the purpose of imparting slipperiness are sufficiently vacuum-dried, then supplied to an extruder, melt-extruded into a sheet at 280 ° C., cooled and solidified, and unoriented A PET sheet is formed. At this time, high-precision filtration is performed at any place where the molten resin is maintained at about 280 ° C. 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 80 to 120 ° C. to obtain a uniaxially oriented PET film.

  Thereafter, an aqueous solution of the copolymer polyester and polyurethane resin is applied to one or both sides of the uniaxially oriented PET film. In order to apply the aqueous coating solution, for example, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, wire barber coating method, pipe doctor method, impregnation Examples thereof include a coating method and a curtain coating method, and these methods can be carried out alone or in combination.

  Subsequently, the edge part of a film is hold | gripped with a clip, it guide | induces to the hot air zone heated at 80-180 degreeC, and is extended | stretched 2.5 to 5.0 times in the width direction after drying. Subsequently, it is guided to a heat treatment zone of 220 to 240 ° C., and heat treatment is performed for 1 to 20 seconds to complete crystal orientation. In this heat treatment step, a relaxation treatment of 1 to 12% may be performed in the width direction or the longitudinal direction as necessary.

  Hereinafter, the phase separation structure of the coating layer obtained in the present invention will be described. Next, the raw materials and production conditions used for the laminated thermoplastic resin film of the present invention will be described in detail, including the condition factors for controlling the phase separation structure.

(1) Phase Separation Structure of Coating Layer In the present invention, the coating layer mainly comprises a polyester phase A (hereinafter sometimes abbreviated as PEs phase) mainly composed of a copolyester resin and a polyurethane resin. The polyurethane phase B as a component (hereinafter sometimes abbreviated as “PU phase”) has a structure in which microphase separation or nanophase separation is performed. When the scanning probe microscope is observed in the phase measurement mode, the area ratio (PEs surface area) of the polyester phase A (indicating a dark hue in the phase image) on the surface of the coating layer defined by the following equation (1): The ratio is 35% or more and less than 90% in a measurement area of 5 μm × 5 μm.
PEs surface fraction (%) = (area of PEs phase A / measurement area) × 100 (1)

The PEs surface fraction on the surface of the coating layer has the following technical significance.
When the PEs surface fraction is less than 35%, the surface fraction of the phase mainly composed of polyurethane-based resin on the surface of the coating layer becomes relatively large, and the frequency with which blocking resistance decreases is increased. On the other hand, when the PEs surface fraction is 90% or more, the frequency of decrease in adhesion increases, and in particular, the decrease in adhesion to a solventless hard coat agent becomes significant.

  The lower limit of the PEs surface fraction on the surface of the coating layer is preferably 40%, more preferably 45%, and particularly preferably 50% from the viewpoint of blocking resistance. On the other hand, the upper limit of the PEs surface fraction is preferably 85%, more preferably 80%, and particularly preferably 75% from the viewpoint of adhesion to the functional layer made of an acrylic resin.

  In the present invention, the phase separation structure on the surface of the coating layer was evaluated using a phase measurement mode (phase mode) using a scanning probe microscope (SPM). The phase mode is a phase lag measurement mode that is performed simultaneously with surface morphology observation in a normal dynamic force mode (DFM mode; when SII NanoTechnology SPM is used).

The measurement principle regarding the evaluation of the phase separation structure of the coating layer by the phase measurement mode (phase mode) of the scanning probe microscope (SPM) will be briefly described.
In the phase mode, the phase delay of the cantilever vibration when the DFM operation is performed is detected. In the DFM operation, the shape is measured by controlling the distance between the probe and the sample so that the vibration amplitude of the resonated cantilever is constant. Here, when the signal that vibrates the bimorph (piezoelectric element) for vibrating the cantilever is called an “input signal”, in the phase measurement mode, the phase delay of the effective cantilever vibration signal with respect to this “input signal” Is detected simultaneously with the vibration amplitude. The phase delay responds sensitively to the influence of surface properties, and the softer the sample surface, the greater the delay. By imaging the magnitude of this phase lag, it becomes possible to observe the distribution of surface physical properties (referred to as phase image or phase image). Therefore, when a plurality of resin phases having different physical properties exist on the surface, the phase separation structure can be evaluated by this measurement method.

  However, the evaluation of the phase separation structure of the coating layer may be performed in other modes such as the friction force measurement mode and the viscoelasticity measurement mode in addition to the phase measurement mode as long as it is a surface property distribution evaluation mode by a scanning probe microscope. It is important to select an observation mode that can evaluate the phase separation structure with high sensitivity. In the phase measurement mode, not only the phase lag due to the difference in viscoelasticity of the coating layer but also the phase lag due to the difference in surface physical properties such as the magnitude of the adsorption force can be detected.

  The phase separation structure of the coating layer in the present invention corresponds to a microphase separation structure or a nanophase separation structure in terms of size. When the PEs phase is regarded as a continuous structure having a major axis and a minor axis, the PEs phase is mainly a continuous structure having a width in the minor axis direction of at most 1 μm and a length in the major axis direction exceeding 1 μm. That is, the area of the portion having the continuous structure is 80% or more, preferably 85% or more, more preferably 90% or more with respect to the entire area of the PEs phase. Moreover, even if the PEs phase is dispersed in an island shape that does not correspond to the continuous structure described in the above definition, the end of the coating layer having a continuous structure appears on the surface. is there.

  The size of the continuous structure of the PEs phase is preferably 1 μm at the maximum in the minor axis direction, more preferably 0.8 μm, still more preferably 0.6 μm, and particularly preferably 0.4 μm. It is. The width in the minor axis direction is not particularly limited as to the lower limit, but in order to maintain a continuous structure, the narrowest portion is preferably 0.01 μm, and particularly preferably 0.05 μm. On the other hand, the size of the continuous structure of the PEs phase is preferably such that the length in the major axis direction exceeds 1 μm, more preferably 1.5 μm or more, further preferably 2.0 μm or more, and particularly preferably 2.5 μm or more. It is.

  As can be seen from the representative examples shown in FIGS. 1 and 8, the phase separation structure of the coating layer in the present invention shows a complicated structure that cannot be seen in nature, and uniquely defines the form of phase separation. Is difficult. The phase separation structure can also be expressed in many ways as follows.

  For example, when the form of the phase-separated structure is expressed as a pattern, it is described in the literature as “dendritic structure” (“Chemical Dictionary”, page 226, June 15, 1979, Sankyo Publishing) Issued by Co., Ltd.), “Rippled structure” (“Pattern”, pages 168-169, issued by Nobara Inc., 2002.0.1), and “Camouflage tone”.

  Further, the phase separation structure on the surface of the coating layer in the present invention is similar to what is expressed as a co-continuous structure in the field of morphology in the polymer blend system. Furthermore, it can also be expressed as a mutual network intrusion structure formed by entanglement of the copolyester resin and the self-crosslinking polyurethane resin.

  In terms of form, the self-similarity of the PEs phase can also be quantitatively expressed using the fractal dimension. For example, as shown in FIGS. 3 and 10, the surface of the coating layer is observed in the phase measurement mode of a scanning probe microscope, and the outline of the interface between the light hue (polyester phase A) and the dark hue (polyurethane phase B) is emphasized. In the obtained phase image, a box counting method is used as an index indicating the complexity of the boundary between the bright hue and the dark hue (interface outline), and is quantitatively expressed using the fractal dimension obtained from the interface outline. can do.

  When the fractal dimension in the unit area is 1, it means a straight line (one dimension), and 2 means a solid surface (two dimensions). That is, the closer the fractal dimension is to 2, the denser the structure. On the other hand, a fractal dimension closer to 1 means a sparse structure.

  Specifically, in the phase image in which the outline of the interface between the light hue (polyester phase A) and the dark hue (polyurethane phase B) is emphasized, the fractal dimension of the boundary line (interface outline) between the light hue and the dark hue is It is preferable that it is 1.60-1.95 in the measurement area of 5 micrometers x 5 micrometers. The upper limit of the fractal dimension is more preferably 1.93, and particularly preferably 1.90. On the other hand, the lower limit of the fractal dimension is more preferably 1.65, and particularly preferably 1.70.

  For example, on the surface of the coating layer shown in FIGS. 4 and 11, the fractal dimension of the boundary line (interface contour) between the light hue (polyester phase A) and the dark hue (polyurethane phase B) is 1.89 and 1. 90. 4 and 11 emphasize the outline of the interface between the light hue and the dark hue in the phase images of FIGS. 1 and 8 showing the typical phase separation structure on the surface of the coating layer in the present invention. It is the figure which showed the boundary line of a dark hue.

  In the present invention, it is important that the coating layer has a microphase separation structure or a nanophase separation structure in order to maximize the functions of the copolyester resin and polyurethane resin used as the raw material of the coating layer. It is. This is because when the two resins are completely compatible, the properties of the two resins cancel each other, and the excellent properties of the copolyester resin or polyurethane resin cannot be expected as a whole. In the coating layer of the present invention, other phase separation structures that can be taken by the PEs phase and the PU phase include those in which the PU phase is dispersed in the PEs phase, and so-called composite forms in which the PES phase is dispersed in the PU phase. It is also possible to adopt a typical sea-island structure. Of course, this sea-island structure is in an incompatible state of the resin, and if one resin phase is increased, the other is inevitably reduced to form a so-called island. Also in the present invention, if the production conditions are controlled, it is possible to form a coating layer composed of a separated phase having such a sea-island structure. When the effect of the present invention is expected by this sea-island structure, it is necessary to examine the structure further.

  However, considering the non-uniform size of the resin phase that forms the island structure and the non-uniform distribution state, the influence of the shape, number, and distribution state of the island phase cannot be ignored. There is also a concern that the properties of the resin constituting the material may be greatly affected. In this case, it is considered advantageous to maintain the uniformity of the material by adopting a phase separation structure in which the PEs phase and the PU phase of the present invention are intertwined with each other. A phase separation structure that adopts a sea-island structure of PEs phase and PU phase can be mentioned as one of the typical embodiments of the present invention.

  In addition, a core / shell structure can be adopted as still another phase separation structure of the coating layer in the present invention. For example, the PEs phase is surrounded by a PU phase, which is further surrounded by a PEs phase. However, in order to form such a core / shell structure, a very high degree of control is required. Also, because of its core / shell structure, it does not seem to be expected to show excellent material behavior. Furthermore, as a mode of the phase separation structure, a laminated structure in which PEs phases and PU phases are regularly arranged alternately can be adopted. However, it is ideal that the phases are arranged in parallel at substantially equal intervals. However, if the phase width is increased, it becomes difficult to uniformly distribute the PEs phase and the PU phase at the interface of the coating layer. This may affect the quality of the laminated thermoplastic resin film. Due to the subtle disposition of the manufacturing conditions, they may be a mixed type while taking the form of a sea-island structure, a core-shell structure, and a laminated structure. However, it is important for maintaining the quality that the PEs phase and the PU phase have a certain size in the coating layer and that they are uniformly and uniformly mixed.

  A polyester phase A mainly composed of a copolyester resin and a polyurethane phase B mainly composed of a polyurethane resin have irregular shapes. And those resin phases form a complicated arrangement | sequence structure arrange | positioned on the base material which consists of a thermoplastic resin film irregularly and densely and uniformly. Moreover, the structure which the other resin phase digged into the surface of one resin phase in the state of incompatibility may be sufficient. 3 and 10, the black portion indicates the polyester phase A and the white portion indicates the polyurethane phase B.

  In the case where two types of resin phases are uniformly arranged with respect to a unit area (for example, 5 × 5 μm), if the size of one resin phase is increased, the size of the other resin phase is restricted. Therefore, a large bias occurs in the presence of the resin phase. As a result, it becomes difficult to maintain a state in which both resin phases are separated and uniformly dispersed and unevenness occurs in the material of the coating layer, which is not preferable for quality control.

  In order to cause both resin phases to phase-separate and to be present in the coating layer in a uniformly mixed state, the PEs phase has a maximum width of 1 μm in the minor axis direction and a length in the major axis direction of 1 μm or more. It is preferable. Of course, when there is no high demand for quality, a structure having a relatively large width of about 6 μm at the maximum in the minor axis direction is also possible. The phase separation structure of this continuous phase (PEs phase) includes the resin composition of the coating liquid used for forming the coating layer, the type and concentration of the surfactant, the coating amount, the drying conditions of the coating layer, and the heat setting conditions. By selectively adopting and controlling them, it can be expressed as a microphase separation structure or a nanophase separation structure specific to the coating layer. In any case, the aspect of the phase separation structure of the polyester phase A and the polyurethane phase B on the surface of the coating layer shown in FIG. 1 and FIG. 8 is a representative for expressing the effect of the laminated thermoplastic resin film of the present invention. It is a model.

Further, the importance of the phase separation structure will be described in detail.
The coating layer in the laminated thermoplastic resin film of the present invention is composed of a copolymer polyester component and a polyurethane component as resin components, and a PE phase having a copolymer polyester resin as a main component and a PU phase having a polyurethane resin as a main component. It is important that the phases are separated and at least the PEs phase has a continuous structure. By phase-separating the above two types of resins without mixing them together, it has excellent adhesion to a base film made of a thermoplastic resin film and has a relatively good solvent resistance. Polymerized polyester resin and polyurethane resin with excellent adhesion to many resins such as hard coat layer, diffusion layer, acrylate resin, etc., which are inferior in solvent resistance. This is because the features of the resin can be fully utilized.

  The polyester phase A constituting the coating layer is preferably composed of a copolyester resin alone, but may contain 0.01 to 40% by mass of a polyurethane resin. Further, the polyester phase A may contain particles in an amount of 0.001 to 20% by mass. Further, in the polyester phase A, a surfactant may be attached to or contained in the resin. Similarly, the polyurethane phase B is preferably composed of a polyurethane resin alone, and can contain particles, a surfactant and the like in an amount as described in the copolymer polyester resin. In particular, in the case of particles having a high affinity with the polyurethane-based resin, it is possible to selectively disperse the polyurethane phase B more selectively than the polyester phase A in the process of forming the coating layer.

  In general, in a composition composed of a mixture of a copolyester resin and a polyurethane resin, the chemical supplementary function is usually such that both are chemically uniform materials and complement each other's properties or functions. Often manifests. On the other hand, the coating layer comprising the polyester phase and the polyurethane phase of the present invention, as described above, the polyester phase and the polyurethane phase are physically separated from each other, resulting in a large bias in the presence of the resin phase. The structure in which both resin phases are separated and uniformly dispersed is maintained. The properties of each resin can be achieved through the surface of each resin phase, for example, in a state in which each resin is phase-separated, such as copolyester resin is anti-blocking and polyurethane resin is adhesive. Sharing. In other words, it is the manifestation of a physical supplementary function, and this very function or principle is a new technical matter that is not recognized at all in the prior art.

  The detailed generation mechanism of the phase separation structure of the coating layer in the present invention is not clear. However, the composition ratio of the copolyester resin and polyurethane resin, the ratio of the water and alcohol dispersion medium, the type of surfactant, the impurities in the surfactant, the pH of the aqueous coating solution, the coating amount of the coating solution, etc. Depending on the balance of delicate conditions such as drying and heat setting time, temperature, and wind speed in the material composition and characteristics, the specific microphase separation structure or nanophase separation structure appears in the coating layer. It can be easily understood from the comparison between the example and the comparative example.

  Furthermore, it seems that the reaction start temperature of the isocyanate group of the polyurethane resin also has a subtle effect. The phase separation structure here does not mean that both the so-called PEs phase and PU phase are separated from each other by a physical boundary, but the boundary is in contact without taking a distance. A lot of copolyester is gathered and biased in the phase, and a lot of polyurethane resin is gathered and biased exclusively in the PU phase, and the boundary between the two layers seems to be separated as if it was clearly distinguishable. Should be seen. In the case of the present invention, there is a possibility that the isocyanate group of the polyurethane-based resin reacts at the boundary, indicating a complicated separation structure.

  The laminated thermoplastic film of the present invention has a coating layer composed of a PEs phase and a PU phase, for example, between a substrate composed of a thermoplastic film and a functional layer such as a hard coat layer or a diffusion layer. It plays the role of an interfacial function that acts on both the base material surface and the functional layer surface equally. Then, both the PEs phase and the PU phase have a structure in which both are separated, and the PEs phase has the excellent properties of the copolyester resin originally possessed by both sides of the coating layer (the interface between the base material and the coating layer, the coating layer). And the interface between the functional layer and the functional layer). That is, the PU phase is in a state in which the excellent properties of the inherent polyurethane-based resin are exerted to the maximum on both sides.

  This is because, in the laminated thermoplastic resin film having a coating layer, the surface of the coating layer has a microphase separation structure or a nanophase separation structure composed of a PEs phase and a PU phase. When the resin is exposed, the properties or functions of the copolyester resin are maximized. Similarly, the polyurethane resin of the PU phase is exposed to maximize the properties or functions inherent in the polyurethane resin. It is because it plays. Therefore, if each of the PEs phase and the PU phase on the surface of the coating layer is distributed in a specific range, the properties or functions of both resins can be exhibited to the maximum. This is because of the unique structure of the laminate, it acts rationally at the interface between the substrate and the coating layer and at the interface between the coating layer and the functional layer.

  Furthermore, in the present invention, when particles are contained in the resin composition constituting the PEs phase and the PU phase, for example, silica particles can be unevenly distributed in the PU phase. This is presumed that the surface energy is closer to the silica particles in the PU phase than in the PEs phase. By making the silica particles unevenly distributed in the PU phase, it is possible to improve the blocking resistance, which is a disadvantage of the polyurethane resin, and to reduce the particle content of the entire coating layer, so that transparency is maintained. It is a structure that is useful for performing functions.

  Similarly, it is suggested that if particles having a surface energy closer to that of the copolyester are selected, the particles can be selectively unevenly distributed in the PEs phase. In a method unpredictable from the prior art, in which particles are unevenly distributed in either a phase separation structure composed of a PEs phase or a PU phase, the slipperiness and blocking properties can be highly improved while maintaining transparency. Therefore, the present invention is also meaningful in that the application range of the material design of the micro phase separation structure or the nano phase separation structure can be expanded.

(2) Substrate film In the present invention, the thermoplastic resin film serving as a substrate is a non-oriented sheet obtained by melt-extrusion or solution extrusion of a thermoplastic resin, and if necessary, a uniaxial direction in the longitudinal direction or the width direction. Or a biaxially or sequentially biaxially stretched in the biaxial direction and heat-set.

  The thermoplastic resin film is a surface activation treatment such as a corona discharge treatment, a glow discharge treatment, a flame treatment, an ultraviolet irradiation treatment, an electron beam irradiation treatment, and an ozone treatment within a range that does not impair the object of the present invention. May be applied.

  The thickness of the thermoplastic resin film used as the base material of the laminated thermoplastic resin film of the present invention can be arbitrarily determined in the range of 30 to 300 μm according to the specification 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. When the film thickness is less than 50 μm, rigidity and mechanical strength tend to be insufficient. On the other hand, when the film thickness exceeds 300 μm, the absolute amount of foreign matter present in the film increases, and thus the frequency of optical defects increases. Moreover, the slit property at the time of cut | disconnecting a film to a predetermined width also deteriorates, and manufacturing cost becomes high. Furthermore, since rigidity becomes strong, it becomes difficult to wind a long film in a roll shape.

  As thermoplastic resins, polyolefins such as polyethylene (PE), polypropylene (PP), polymethylpentene (TPX), polyethylene terephthalate (PET), polyethylene-2,6-naphthalate (PEN), polytetramethylene terephthalate (PTT) , Polyester resins such as polybutylene terephthalate (PBT), polyamide (PA) resins such as nylon 6, nylon 4, nylon 66, nylon 12, polyimide (PI), polyamideimide (PAI), polyethersulfone (PES), Polyetheretherketone (PEEK), polycarbonate (PC), polyarylate (PAR), cellulose propionate, polyvinyl chloride (PVC), polyvinylidene chloride, polyvinyl alcohol (PVA), polyethylene (Ether imide) (PEI), polyphenylene sulfide (PPS), polyphenylene oxide, polystyrene (PS), syndiotactic polystyrene, and norbornene-based polymer. In addition to using these polymers alone, they may be a copolymer containing a small amount of a copolymer component, or one or more other thermoplastic resins may be blended.

  Among these thermoplastic resins, polyethylene terephthalate, polypropylene terephthalate, polyethylene-2,6-naphthalate, syndiotactic polystyrene, norbornene-based polymer, polycarbonate, polyarylate and the like are preferable. In addition, a resin having a polar functional group such as polyester or polyamide is preferable from the viewpoint of adhesion to the coating layer.

  Among them, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polypropylene terephthalate or a copolymer mainly composed of these resin components is more preferable, and in particular, biaxial orientation formed from polyethylene terephthalate. Films are particularly suitable.

  For example, when a polyester copolymer having polyethylene terephthalate as a basic skeleton is used as a resin for forming a thermoplastic resin film, the ratio of the copolymer component is preferably less than 20 mol%. If it is 20 mol% or more, the film strength, transparency, and heat resistance may be inferior. Examples of the dicarboxylic acid component that can be used as the copolymerization component include aliphatic dicarboxylic acids such as adipic acid and sebacic acid, aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid, and trimellilotic acid. And polyfunctional carboxylic acids such as pyromellilottic acid. Examples of the glycol component that can be used as a copolymer component include fatty acid glycols such as diethylene glycol, 1,4-butanediol, propylene glycol, and neopentyl glycol; aromatic glycols such as p-xylene glycol; 1,4-cyclohexane Examples include alicyclic glycols such as dimethanol; polyethylene glycol having an average molecular weight of 150 to 20,000.

  In addition, the thermoplastic resin can contain various additives in addition to the catalyst, as long as the effects of the present invention are not hindered. Examples of additives include inorganic particles, heat-resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, ultraviolet absorbers, light-resistant agents, flame retardants, heat stabilizers, antioxidants, Examples thereof include an antigelling agent and a surfactant.

  The above particles have a handling property (sliding property, running property, blocking property, air release property of the accompanying air at the time of winding, etc.) at the time of winding up or unwinding in the form of a thermoplastic resin film. From the point, it is used to impart moderate surface irregularities to the film surface.

  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, lithium fluoride, zeolite , Molybdenum sulfide, mica and the like. Examples of the heat resistant polymer particles include crosslinked polystyrene particles, crosslinked acrylic resin particles, crosslinked methyl methacrylate particles, benzoguanamine / formaldehyde condensate particles, melamine / formaldehyde condensate particles, and polytetrafluoroethylene particles. .

  When a polyester film is used as the base film, among the above particles, silica particles are relatively close to the polyester resin and easily obtain high transparency, and are therefore most suitable for applications where transparency is strongly required. . On the other hand, white pigments such as titanium oxide are suitable for applications that require concealment. Moreover, the particle | grains contained in a thermoplastic resin film may be used alone or in combination.

  From the viewpoint of the balance between transparency and handling properties, the type, average particle size, and addition amount of the above particles are 0.01 to 2 μm in average particle size, and 0.01 to 5.0 particle content in the film. What is necessary is just to determine according to the use of a film in the range of the mass%. In addition, when the laminated thermoplastic resin film of the present invention is used for applications in which transparency is highly required, the thermoplastic resin film of the substrate substantially contains particles that cause a decrease in transparency. It is preferable to make it the structure which makes a coating layer contain particle | grains without doing.

  The above-mentioned “substantially no particles are contained in the thermoplastic resin film of the substrate” means, for example, in the case of inorganic particles, when inorganic elements are quantified by fluorescent X-ray analysis, 50 ppm or less, preferably It means a content of 10 ppm or less, most preferably a detection limit or less. This means that even if particles are not actively added to the base film, contaminants derived from foreign substances and raw material resin or dirt adhering to the line or equipment in the film manufacturing process will be peeled off and mixed into the film. It is because there is a case to do.

  Moreover, the layer structure of the thermoplastic resin film used as the substrate in the present invention may be a single layer, or a laminated structure imparted with a function that cannot be obtained with a single layer. In the case of a laminated structure, a coextrusion method is preferable.

  The case where polyester is used as a raw material for the thermoplastic resin film will be described in detail below as a representative example of the method for producing the base film.

  The intrinsic viscosity of the polyester pellet used as the film raw material is preferably in the range of 0.45 to 0.70 dl / g. When the intrinsic viscosity is less than 0.45 dl / g, breakage tends to occur frequently during film production. On the other hand, if the intrinsic viscosity exceeds 0.70 dl / g, the filtration pressure rises greatly, high-precision filtration becomes difficult, and the productivity tends to decrease.

  Moreover, when using for an optical functional film or an optical functional sheet, it is preferable to remove the foreign material contained in the raw material polyester which causes an optical defect. In order to remove foreign substances in the polyester, high-precision filtration is performed at any place where the molten resin is kept at about 280 ° C. during the melt extrusion. The filter medium used for high-precision filtration of the molten resin is not particularly limited, but in the case of a stainless steel sintered filter medium, the removal performance of aggregates and high melting point organic substances mainly composed of Si, Ti, Sb, Ge, Cu Excellent and suitable.

  The filter 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, 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 a filter medium with a filtration particle size (initial filtration efficiency of 95%) of 15 μm or less, but it is extremely important to obtain a film with few optical defects. It is.

  In the molten resin extrusion process, even fine foreign matter that passes through the filter medium is crystallized around the foreign matter in the cooling process of the sheet-like melt. A difference in thickness is generated to cause 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 μm or more and the depth of the concave part adjacent to the convex part is 0.5 μm or more. In this case, due to the lens effect, an object having a size of 20 μm may be visually recognized as a size of 50 μm or more, and may be recognized as an optical defect of a size of 100 μm or more.

  In order to obtain a highly transparent film, it is preferable not to contain particles in the base film, but as the particle content is lower and the transparency is higher, optical defects due to minute irregularities tend to become clearer. In addition, since the surface of a thick film is less likely to be cooled rapidly than a thin film and crystallization tends to proceed, it is necessary to rapidly cool the entire film when manufacturing an unoriented sheet. As a method for cooling the non-oriented sheet, a method in which the molten resin is extruded in a sheet form from a slit portion of a die onto a rotating cooling drum, and the sheet-like melt is brought into close contact with the rotating cooling drum, and is rapidly cooled into a sheet is suitable. It is. 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 stream is effective.

(3) Coating layer The laminated thermoplastic resin film of the present invention comprises an aqueous coating liquid mainly comprising a resin containing a copolyester resin and a polyurethane resin, a dispersion medium containing water and alcohol, and a surfactant. A coating process that continuously applies to one or both sides of a traveling thermoplastic resin film, a drying process that dries the coating layer (coating layer), a stretching process that stretches at least uniaxially, and a stretched coating film that is heat-set A laminated thermoplastic resin film provided with a coating layer having a microphase-separated structure or a nanophase-separated structure, which is obtained by continuously forming through a heat setting treatment step to be processed, is produced. Moreover, at least one kind of crosslinking agent selected from an epoxy-based crosslinking agent, a melamine-based crosslinking agent, and an oxazoline-based crosslinking agent may be mixed in a coating solution and heat-treated to form a crosslinked structure in the copolymerized polyester-based resin. .

In the method for producing a laminated thermoplastic resin film provided with a coating layer having a microphase separation structure or a nanophase separation structure, the mass ratio (A / B) of the copolymerized polyester resin A and the polyurethane resin B is 30. / 70 to 70/30, and it is preferable to satisfy the following conditions (i) to (vi). The same applies when the coating solution contains a crosslinking agent.
(I) The passage time of the film from immediately after application of the coating solution to the entrance of the drying step is less than 2 seconds (ii) at a temperature of 120 to 150 ° C. for 0.1 to 5 seconds in the drying step (iii) The wind speed is 30 m / sec or more. (Iv) The heat setting process is divided into a plurality of heat setting zones continuously, and each zone is partitioned so that the temperature can be controlled independently, and the film passes. The temperature of the first heat setting zone is 190 to 200 ° C., the temperature of the heat setting zone set to the maximum temperature is 210 to 240 ° C., and is set to the maximum temperature from the outlet of the first heat setting zone. The passage time of the film to the heat setting zone (in the case where there are a plurality of heat setting zones on the most inlet side) is 10 seconds or less. (V) A nonionic surfactant or a cationic surfactant is added to the coating solution at 0. 01 to 0.18 final coating weight mass% formulation (vi) coating layer 0.005~0.20g / m ²

In the production of the laminated thermoplastic resin film, it is more preferable that the following conditions (vii) to (ix) are satisfied.
(Vii) The passage time of the film from immediately after application of the coating solution to the entrance of the drying step is less than 1.5 seconds (viii) In the drying step, the temperature is 130 to 150 ° C. for 0.5 to 3 seconds (ix) heat setting treatment In the process, the temperature of the heat setting zone set to the maximum temperature is 225 to 235 ° C., and the heat setting zone set to the maximum temperature from the outlet of the first heat setting zone (if there are a plurality, the most inlet The passage time of the film to the heat setting zone on the side) is 5 seconds or less

  In addition, the coating layer laminated by the in-line coating method contains fine particles having an appropriate particle size, and by forming appropriate irregularities on the surface of the coating layer, slipping property, winding property, and scratch resistance are improved. Can be granted. For this reason, it is not necessary to contain fine particles in the thermoplastic resin film, and high transparency can be maintained.

  When the laminated thermoplastic resin film of the present invention is used as a substrate for an optical functional film or an optical functional sheet, the three-dimensional center plane average surface roughness (SRa) of the coating layer surface is 0.002 to 0.010 μm. And smooth. The upper limit of SRa is more preferably 0.0080 μm and particularly preferably 0.0060 μm from the viewpoint of transparency. On the other hand, the lower limit of SRa is more preferably 0.0025 μm, particularly preferably 0.0030 μm, from the viewpoints of handling properties such as slipping and winding properties, and scratch resistance.

  A smooth surface having an SRa of less than 0.002 μm 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 0.010 μm, haze is increased and transparency is deteriorated, which is not preferable as a base film of an optical functional film or an optical functional sheet.

In a preferred embodiment of the present invention, the coating layer has the following four morphological and structural characteristics, and can be obtained by the following means.
(A) Microphase separation or nanophase separation into a polyester phase and a polyurethane phase, and the polyester phase has a specific area ratio (PEs surface fraction) (b) The composition ratio of the resin component of the coating layer is defined as the surface (C) The coating layer has a crosslinked structure (d) When the coating layer contains particles, the particles are unevenly distributed in the polyester phase or the polyurethane phase

  The polyester phase mainly composed of a copolyester resin preferably has a continuous structure having a maximum width of 1 μm and a length exceeding 1 μm, more preferably the copolyester phase and the polyurethane phase have a cocontinuous structure. Structure. Within the range of the PEs surface fraction defined in the present invention, the polyester phase mainly composed of the copolyester resin has a fine continuous structure with a width of 1 μm at the maximum and a length of more than 1 μm. Visually uniform adhesion can be obtained.

  In a polyester phase composed mainly of a copolyester resin, the phase separation structure where the width exceeds 1 μm at the maximum is locally applied to a functional layer such as a hard coat layer, a diffusion layer, or a prism layer. , A place with poor adhesion occurs. If a portion having poor adhesion exists on the surface of the coating layer, it may lead to macroscopic peeling starting from that portion. In order to achieve a fine continuous structure with a maximum width of 1 μm in the polyester phase, it is important to appropriately select the time and heat setting conditions required to reach the maximum temperature in the heat setting zone from the transverse stretching zone. is there. In particular, when the time required from the transverse stretching zone to the zone where the maximum temperature is reached in the heat setting zone is too long, the phase separation of the coating layer proceeds excessively, resulting in a polyester phase mainly composed of a copolyester resin. In other words, the locations where the width is less than 1 μm are scattered at the narrowest portion. Specific heat setting conditions for producing the laminated thermoplastic resin film of the present invention will be described later.

  In order to control the final phase separation structure on the surface of the coating layer, the solvent evaporation rate in the drying step described later and the subsequent heat treatment are extremely important. By controlling the solvent evaporation rate in the drying process, the composition ratio of the polyester component and the polyurethane component on the surface of the coating layer can be changed.

  For example, when a mixed solvent of water / isopropyl alcohol is used, the ratio of water increases in the solvent remaining on the surface in the late drying process under weak drying conditions. Therefore, the ratio in which the polyurethane-based resin having relatively high hydrophilicity is present on the surface of the coating layer is higher than when the coating layer is dried under strong conditions. Also, changing the coating amount has the same effect as controlling the solvent evaporation rate. That is, when the coating amount is increased, drying takes time, and the remaining solvent existing on the coating surface immediately before drying increases the ratio of water. That is, the ratio of the polyurethane component on the surface can be made higher than when the coating amount is small.

  In the stretching step and the heat setting treatment step, the phase separation of the polyester component and the polyurethane component proceeds, but when either one of the thermal crosslinking starts, the mobility of each phase is greatly reduced, and the progress of the phase separation is suppressed. . That is, the phase separation structure can be controlled by controlling the heating conditions in the stretching process and the heat setting process.

  As described above, the surface phase separation structure and the existence ratio of each phase are strictly controlled by controlling the surface ratio of polyester / polyurethane in the drying process and controlling the progress of phase separation in the stretching process and heat setting process. Is possible. Further, by controlling the surface energy of the particles to be contained in the coating layer, the particles are selectively dispersed in either the polyester phase mainly comprising a copolyester resin or the polyurethane phase mainly comprising a polyurethane resin. be able to.

  The coating layer of the laminated thermoplastic resin film of the present invention contains a copolymerized polyester resin and a polyurethane resin as main resin components. The copolyester resin alone has sufficient adhesion to the polyester substrate film, but is inferior to adhesion to the acrylic resin used for prism lenses and hard coats. Further, since it is a relatively brittle resin, it tends to cause cohesive failure with respect to impact during cutting. On the other hand, the polyurethane resin alone is relatively excellent in adhesion to the hard coat layer, the diffusion layer, and the acrylate resin, but is inferior in adhesion to the polyester base film and inferior in blocking resistance. Therefore, it is necessary to contain a large amount or a large particle size or to increase the content of the particle. As a result, since the haze of the film increases, it is not preferable as a substrate film for an optical functional film or an optical functional sheet having a particularly strong demand for transparency.

(3-1) Coating liquid preparation process In this invention, a coating layer is formed using the apply | coating method. Materials used for the coating liquid are a resin and a dispersion medium or a solvent. In the present invention, the coating solution used for forming the coating layer is preferably aqueous. Moreover, in this invention, it is preferable embodiment to use particle | grains and surfactant together with a resin component. Furthermore, additives such as antistatic agents, ultraviolet absorbers, organic lubricants, antibacterial agents, and photooxidation catalysts can be used as necessary. In addition, a catalyst may be added to the coating solution in order to promote the thermal crosslinking reaction of the resin. For example, various chemicals such as inorganic substances, salts, organic substances, alkaline substances, acidic substances and metal-containing organic compounds can be used. Substances can be used. Moreover, in order to adjust pH of aqueous solution, you may add an alkaline substance or an acidic substance. The coating solution is obtained by dispersing or dissolving the resin in a dispersion medium or solvent under stirring, and then using various additives as necessary in addition to the particles and surfactant to obtain a desired solid content concentration. Adjust until diluted.

  Further, in the laminated film of the present invention, the coating liquid can be microfiltered in order to uniformly disperse the resin components and particles of the coating liquid, and to remove foreign matters such as coarse particle aggregates and dust in the process. preferable.

  There is no particular limitation on the type of filter medium for finely filtering the coating solution as long as it has the above-mentioned 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 solution is not particularly limited as long as it has the above performance and does not adversely affect the coating solution, and examples thereof include stainless steel, polyethylene, polypropylene, and nylon.

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 filter medium having a filtration performance of 5 μm or less, particularly preferably a filter medium having a filtration performance of 1 μm or less. is there. Most preferred is a method in which filters having different filtration performance are used in combination. When a filter medium having a filtration particle size exceeding 25 μm is used, removal of coarse aggregates tends to be insufficient. Therefore, the coarse aggregate that could not be removed by filtration spreads due to the orientation stress in the uniaxial or biaxial orientation process after coating and drying, and is recognized as an aggregate of 100 μm or more, which is likely to cause optical defects.
The raw materials used for the coating solution will be described in detail below.

(A) Resin When the composition ratio of the resin component of the coating layer formed on the base material made of the thermoplastic resin film is to prepare a coating liquid containing the copolymer polyester resin (A) and the polyurethane resin (B), The mass ratio based on the solid content of the resin (A) and the resin (B) is preferably (A) / (B) = 70/30 to 30/70, particularly preferably in the range of 60/40 to 40/60. . In the present invention, as the resin constituting the coating layer, a third resin other than the copolyester resin and the polyurethane resin can be used in combination. Moreover, you may use a crosslinking agent together.

  In the present invention, the PEs surface fraction on the surface of the coating layer and the mass ratio of PEs in the resin component of the coating layer do not correspond as shown in FIGS. FIG. 6 clearly shows that even when the mass ratio of PEs in the resin component of the coating layer is 50%, the PEs surface fraction on the surface of the coating layer changes from 30 to 91%. FIG. 13 clearly shows that the PEs surface fraction on the surface of the coating layer varies from 26 to 86% even if the PEs mass ratio in the resin component of the coating layer is 45%. This suggests that the composition ratio of the copolyester resin and the polyurethane resin is different between the surface and the inside of the coating layer. That is, in the present invention, it means that the constituent ratio of the copolyester resin and the polyurethane resin can be arbitrarily controlled in the thickness direction of the coating layer.

  In addition, the hardness index of the coating layer surface is set to 3.0 to 15.0 nm by setting the ratio of the copolyester resin (A) and the polyurethane resin (B) in the coating layer within the above range. Can do. When the hardness index of the coating layer surface is less than 3.0 nm, the coating layer becomes brittle. Therefore, after forming a functional layer such as a hard coat layer, a diffusion layer, a prism layer, etc. containing acrylic resin as a constituent component, it is sufficient for the shearing force during high-speed cutting in the processing step of high-speed cutting to a predetermined size. Adhesion is difficult to obtain. Also. When the hardness index of the coating layer surface exceeds 15.0 nm, the blocking resistance tends to be lowered. Furthermore, there exists a tendency for the applicability | paintability to a base film, adhesiveness, and solvent resistance to become inadequate.

  The formation process of the phase separation structure of the water-dispersed copolyester component and the hydrophilic polyurethane component in the present invention is estimated as follows. Both resin components mixed with a common solvent are in a state of being uniformly dispersed or dissolved in the coating solution. After the coating on the PET film, the coated surface after the drying process is in a uniform state without a clear phase separation structure. Thereafter, the phase separation structure is developed by heat treatment in the stretching step and the heat setting treatment step. That is, it is separated into a phase mainly composed of copolymer polyester and a phase mainly composed of polyurethane. Further, as the phase separation progresses, the surface presence ratio of the copolyester component having a lower surface energy is considered to increase.

(Copolymerized polyester resin)
The copolymer polyester resin used for the coating layer of the present invention preferably comprises an aromatic dicarboxylic acid component and a glycol branched with ethylene glycol as the glycol component. Examples of the branched glycol component include 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, and 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-hexyl-1,3-propanediol 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl-1,3-propanediol, 2, Such as 2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, and 2,2-di-n-hexyl-1,3-propanediol. And the like.

  The molar ratio of the branched glycol component is preferably 10 mol%, particularly preferably 20 mol%, based on 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, 1,4-cyclohexanedimethanol or the like may be used in combination.

  As the aromatic dicarboxylic acid component, terephthalic acid and isophthalic acid are most preferred. Other aromatic dicarboxylic acids, in particular, aromatic dicarboxylic acids such as diphenylcarboxylic acid and 2,6-naltalenedicarboxylic acid may be added and copolymerized within a range of 10 mol% or less with respect to the total dicarboxylic acid component. Good.

  As the copolymer polyester resin used as the resin component of the coating layer in the present invention, it is preferable to use a water-soluble or water-dispersible resin. Therefore, in addition to the dicarboxylic acid component, in order to impart water dispersibility to the polyester, it is preferable to use 5-sulfoisophthalic acid or an alkali metal salt thereof in the range of 1 to 10 mol%. For example, sulfoterephthalic acid , 5-sulfoisophthalic acid, 4-sulfonaphthaleneisophthalic acid-2,7-dicarboxylic acid and 5- (4-sulfophenoxy) isophthalic acid or alkali metal salts thereof.

(Polyurethane resin)
The polyurethane resin used for the coating layer of the laminated thermoplastic resin film of the present invention is preferably a water-soluble or water-dispersible resin. For example, a heat-reactive water-soluble urethane, which is a resin containing a block-type isocyanate group, in which a terminal isocyanate group is blocked with a hydrophilic group (hereinafter, abbreviated as a block).

  Examples of the isocyanate group blocking agent include phenols, alcohols, lactam oximes, or active methylene compounds containing bisulfites and sulfonic acid groups. The blocked isocyanate group makes the urethane prepolymer hydrophilic or water-soluble. When heat energy is applied to the resin in the drying process or heat setting process during film production, the blocking agent is detached from the isocyanate group, so that the resin is a water-dispersible copolyester mixed with a self-crosslinked stitch. While immobilizing the resin, it also reacts with the end groups of the resin. The resin under preparation of the coating solution is hydrophilic and has poor water resistance, but when the thermal reaction is completed by coating, drying and heat setting, the hydrophilic group of the urethane resin, that is, the blocking agent is released, so the water resistance is good. A coating film is obtained.

  Among the 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. The chemical composition of the urethane prepolymer used in the resin includes (1) an organic polyisocyanate having two or more active hydrogen atoms in the molecule, or a molecular weight having at least two active hydrogen atoms in the molecule. Is a compound having a molecular weight of 200 to 20,000, (2) an organic polyisocyanate having two or more isocyanate groups in the molecule, or (3) a chain extender having at least two active hydrogen atoms in the molecule. And a compound having a terminal isocyanate group.

  The compound (1) generally known is a compound containing two or more hydroxyl groups, carboxyl groups, amino groups or mercapto groups at the terminal or in the molecule, and particularly preferable compounds include polyether polyols. And polyether ester polyols. Examples of polyether polyols include, for example, compounds obtained by polymerizing ethylene oxide and alkylene oxides such as propylene oxide, styrene oxide and epichlorohydrin, or random polymerization, block polymerization, or addition polymerization to polyhydric alcohols. The obtained compound is mentioned.

  Examples of the polyester polyol and the polyether ester polyol mainly include linear or branched compounds. Polyvalent saturated or unsaturated carboxylic acids such as succinic acid, adipic acid, phthalic acid and maleic anhydride, or the carboxylic acid anhydride, ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1 Condensation with polyvalent saturated and unsaturated alcohols such as 1,6-hexanediol and trimethylolpropane, polyalkylene ether glycols such as relatively low molecular weight polyethylene glycols and polypropylene glycols, or mixtures of these alcohols Can be obtained.

  Furthermore, polyester polyols include polyesters obtained from lactones and hydroxy acids. Further, as the polyether ester polyol, polyether esters obtained by adding ethylene oxide or propylene oxide or the like to polyesters produced in advance can be used.

  Examples of the organic polyisocyanate (2) include isomers of toluylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 4,4. -Alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate, or a single or a plurality of these compounds with trimethylolpropane and the like in advance. Examples include added polyisocyanates.

  Examples of the chain extender having at least two active hydrogens in (3) include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, glycerin, trimethylolpropane, and Examples include polyhydric alcohols such as pentaerythritol, diamines such as ethylenediamine, hexamethylenediamine, and piperazine, amino alcohols such as monoethanolamine and diethanolamine, thiodiglycols such as thiodiethylene glycol, and water.

  In order to synthesize a urethane prepolymer, it is usually reacted at a temperature of 150 ° C. or lower, preferably 70 to 120 ° C. for 5 minutes to several hours by a single-stage or multi-stage isocyanate polyaddition method using the chain extender. . The ratio of isocyanate groups to active hydrogen atoms can be freely selected as long as it is 1 or more, but it is necessary that free isocyanate groups remain in the obtained urethane prepolymer. Furthermore, the content of free isocyanate groups 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.

  The obtained urethane prepolymer is preferably blocked using bisulfite. Mix with aqueous bisulfite solution and allow reaction to proceed with good agitation for about 5 minutes to 1 hour. 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. When the composition is used, it is prepared to have an appropriate concentration and viscosity. However, when heated to about 80 to 200 ° C., the bisulfite of the blocking agent is dissociated and the active isocyanate group is regenerated, so that the prepolymer A polyurethane polymer is produced by a polyaddition reaction that takes place within or between the molecules of the polymer, or has the property of causing addition to other functional groups.

  As an example of the resin (B) containing a block type isocyanate group described above, trade name Elastron manufactured by Daiichi Kogyo Seiyaku Co., Ltd. is typically exemplified. Elastolone is a compound in which an isocyanate group is blocked with sodium bisulfite, and is water-soluble due to the presence of a carbamoylsulfonate group having strong hydrophilicity at the molecular end.

(B) Crosslinking agent In this invention, in order to improve the heat-and-moisture resistance of a coating layer, a crosslinking agent is added to a coating liquid, and then a heat treatment is performed to form a coating layer containing a resin having a crosslinked structure. As the crosslinking agent, at least one selected from an epoxy crosslinking agent, a melamine crosslinking agent, and an oxazoline crosslinking agent is used. The cross-linking agent can be selected in consideration of the affinity with the copolymerized polyester resin used in the coating solution and the wet heat resistance required for the coating layer.

  In particular, when a high degree of wet heat resistance is required, an epoxy-based crosslinking agent or a melamine-based crosslinking agent is preferable among the above-mentioned crosslinking agents. Although it does not specifically limit as an epoxy-type crosslinking agent, For example, the water-soluble epoxy crosslinking agent made from Nagase Kasei Kogyo Co., Ltd. (Deconal series; EX-521, EX-512, EX-421, EX-810, EX-811). , EX-851, etc.) are commercially available. Examples of the melamine-based crosslinking agent include Sumitomo Chemical's Smitex Resin Series (M-3, MK, M-6, MC, etc.) and Miwa Chemical Co., Ltd. methylated melamine resin (MW-22, MX). -706 etc.) are commercially available. Moreover, as an oxazoline-type crosslinking agent, Nippon Shokubai Epochros series (WS-700), Shin-Nakamura Chemical Co., Ltd. NX Linker FX, etc. are available as a commercial item.

  The coating layer is preferably 5 to 40% by mass, more preferably 10 to 30% by mass with respect to the total amount (100% by mass) of the copolyester resin and the crosslinking agent in the coating layer. It is preferably contained in the forming coating solution. When the content of the cross-linking agent exceeds 40% by mass, the coating layer becomes brittle and can withstand high-speed cutting in the processing step after forming a functional layer such as a hard coat layer or a diffusion layer made of an acrylate resin. In some cases, sufficient adhesion cannot be obtained. On the other hand, if the content of the crosslinking agent is less than 5% by mass, it may be difficult to obtain durability required in recent years. In the coating solution, a catalyst may be added as necessary to promote crosslinking.

(C) Solvent In the present invention, the solvent broadly includes not only a solution for dissolving the resin but also a dispersion medium used for dispersing the resin in the form of particles. In order to carry out the present invention, various solvents such as an organic solvent and an aqueous solvent can be used.

  The solvent used in the coating solution is preferably a mixed solution in which water and alcohols such as ethanol, isopropyl alcohol, and benzyl alcohol are mixed within a range of 30 to 50% by mass in the total coating solution. Furthermore, if it is less than 10 mass%, you may mix in the range which can dissolve organic solvents other than alcohol. However, the total of alcohols and other organic solvents in the coating solution is less than 50% by mass.

  When the addition amount of the organic solvent is less than 50% by mass with respect to the total solvent, there are advantages that the drying property is improved at the time of 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 with respect to the total solvent, 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 liquid is increased and the coating property is lowered, which may cause a poor appearance of the coating film. Furthermore, due to the volatilization of the organic solvent, there is a high risk of fire and the like. In addition, when the amount of the organic solvent added is less than 30% by mass with respect to the total solvent, the ratio of water is relatively increased, and the highly hydrophilic polyurethane component is segregated on the surface of the coating layer, and finally the lamination heat obtained. In the plastic resin film, it is difficult to make the PEs surface fraction on the surface of the coating layer within the range defined in the present invention.

(D) pH adjustment of coating solution The coating solution used for forming a coating layer in the present invention preferably has a pH in the range of 5 or more and less than 8. When the pH of the coating solution is less than 5, the PEs surface fraction tends to be larger than the range defined by the present invention, and the adhesion tends to be inferior. On the other hand, if the pH of the coating solution is 8 or more, depending on the type of particles, significant aggregation occurs, haze increases, and transparency is deteriorated, which is not preferable. The pH adjuster is not particularly limited as long as it does not adversely affect adhesion, blocking resistance, and coatability or can be ignored. For example, sodium bicarbonate or sodium carbonate can be used to increase the pH, and acetic acid or the like can be used to decrease the pH.

(E) Concomitant use of surfactants When applying the aqueous coating solution to the surface of the base film, a surfactant is generally used to improve the wettability of the film and to apply the coating solution uniformly. The In the present invention, a surfactant can be used as one of means for controlling a specific PEs surface fraction on the surface of the coating layer.

  The type of the surfactant is not particularly limited as long as a good coating property is obtained and the surface fraction of PEs specified in the present invention is obtained. Among the surfactants, a fluorosurfactant is suitable for obtaining good coatability with a small amount of addition. Furthermore, in order to obtain the PEs surface fraction specified in the present invention, it is preferable to blend 0.01 to 0.18% by mass of a cationic surfactant or a nonionic surfactant with respect to the coating solution.

  When an anionic surfactant is used, the compatibility with the above-described copolymerized polyester and polyurethane may be increased, and the phase separation structure defined in the present invention is difficult to obtain. The addition amount of the surfactant can be appropriately selected as long as it does not inhibit the adhesion with a functional layer such as a hard coat layer or a diffusion layer and can provide good coating properties. For example, 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 are likely to aggregate, resulting in an increase in the haze of the obtained laminated film, which is not particularly preferred as an optical functional film or a substrate film of an optical functional sheet. . In addition, the surfactant component may bleed out on the surface of the coating layer and adversely affect the adhesion. On the other hand, good coatability cannot be obtained at a critical micelle concentration or less. Moreover, it becomes difficult to control within the range of the PEs surface fraction defined in the present invention.

(Surfactant purification)
The surfactant used in the present invention is preferably a purified one. In general, surfactants on the market often contain a small amount of impurities. In particular, polyethylene glycol as an impurity may inhibit obtaining a good phase separation structure depending on the content thereof. In order to prevent this, it is preferable to use a purified surfactant that has been subjected to a pretreatment to remove impurities from the surfactant.

The pretreatment process for removing impurities is not particularly limited as long as the impurities can be removed without altering the surfactant. For example, the following method is mentioned.
A method in which at least a surfactant and polyethylene glycol are dissolved in an organic solvent that can be dissolved, allowed to stand at a low temperature, the surfactant as a main component is saturated and precipitated, and then filtered to take out the surfactant with improved purity. Is mentioned. In the case of a perfluoroalkylethylene oxide adduct surfactant, the purity of the surfactant is improved by dissolving it in isopropyl alcohol on a hot bath at 30 ° C. and allowing it to stand at 0 ° C. for about 24 hours, and then filtering out the precipitate. An active agent can be obtained.

(F) Particles The haze of the laminated thermoplastic resin film of the present invention is 1.5% or less when used as an optical functional film or a base film of an optical functional sheet that is highly required for transparency. It is important. The haze is more preferably 1.0% or less. When the haze exceeds 1.5%, when the film is used for a lens film for LCD, a base film for backlight or the like, the sharpness of the screen is lowered, which is not preferable.

  In order to make the haze of the laminated thermoplastic resin film of the present invention 1.5% or less, it is preferable not to contain particles in the base film. When particles are not included in the base film, scratch resistance, handling property when winding in roll form, and handling property when unwinding (sliding property, running property, blocking property, air escape of accompanying air during winding) In order to improve properties, etc., it is preferable that a specific amount of particles having an appropriate size is contained in the coating layer to form appropriate irregularities on the surface of the coating layer.

  The particles are preferably particles having a high affinity with the copolymer polyester resin or the polyurethane resin, and it is preferable that there is a difference that the affinity for both is unevenly distributed in either phase. By making the particles unevenly distributed in one of the phase-separated resins, the particles are gathered moderately, and with the addition of relatively few particles, that is, excellent blocking resistance can be obtained without significantly increasing haze. is there.

  The 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, calcium fluoride, fluorine. Inorganic particles such as lithium fluoride, zeolite, molybdenum sulfide, mica, crosslinked polystyrene particles, crosslinked acrylic resin particles, crosslinked methyl methacrylate particles, benzoguanamine / formaldehyde condensate particles, melamine / formaldehyde condensate particles, polytetrafluoroethylene particles And heat resistant polymer particles.

Among these particles, silica particles are preferable from the following points.
The first advantage is that a highly transparent film is easily obtained because the refractive index is relatively close to the resin component of the coating layer. The second advantage is that the silica particles tend to be unevenly distributed in the phase-separated polyurethane-based resin phase, and the inherent property of the polyurethane-type resin is inferior in the blocking resistance of the polyurethane-based resin phase present on the surface of the coating layer. It is a point that can be complemented. This is presumably because the surface energy of the silica particles and the polyurethane resin is closer to that of the copolyester resin and the affinity is high.

  The shape of the particles is not particularly limited, but particles that are close to spherical are preferable from the viewpoint of imparting easy slipperiness.

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

  Moreover, you may contain 2 or more types of particle | grains from which an average particle diameter differs in a coating layer. Moreover, you may contain the same kind of particle | grains from which an average particle diameter differs. In any case, the average particle diameter and the total content of the particles may be in the above ranges. When applying the coating solution, it is preferable to arrange a filter medium so that the coating solution is precisely filtered immediately before coating in order to remove coarse aggregates of particles in the coating solution.

  The average particle diameter of the particles is preferably 20 to 150 nm, more preferably 40 to 60 nm. When 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 diameter of the particles exceeds 150 nm, the haze increases and the particles easily fall off.

  In the present invention, sufficient blocking resistance and scratch resistance may not be obtained with only particles A 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 B having a larger average particle size. The average particle size of the particles B 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 B 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 B exceeds 1000 nm, the haze tends to increase. Further, the particle B is preferably an aggregate particle in which primary particles are aggregated, and it is possible to use a particle having a ratio of the average particle diameter in the aggregated state to the average particle diameter of the primary particle of 4 times or more. From the point of view, it is preferable.

  When using two types of particles, for example, the content ratio (P1 / P2) of particles A (average particle size: 20 to 150 nm) and particles B (average particle size: 160 to 1000 nm) in the coating layer is set to 5 to 30. And content of particle | grains B shall be 0.1-1 mass% with respect to solid content of a coating layer. Controlling the content of the two kinds of particles having 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, handling properties and blocking resistance. It is suitable. When the content of the particles B exceeds 1% by mass with respect to the coating layer, the haze increases significantly.

The average primary particle size and average particle size of the particles are measured by the following method.
Take a photograph of the particles with an electron microscope, measure the maximum diameter of 300-500 particles at a magnification such that the size of one smallest particle is 2-5 mm, and calculate the average value as the average primary particle size or Average particle diameter. Moreover, when calculating | requiring the average particle diameter of the particle | grains in the coating layer of a laminated film, the cross section of a laminated film is image | photographed by 120,000 times using a transmission electron microscope (TEM), and it exists in the cross section of a coating layer. The maximum diameter of the particles can be determined. The average particle diameter of the particles B made of aggregates is obtained by photographing 300 to 500 cross sections of the coating layer of the laminated film at a magnification of 200 using an optical microscope, and measuring the maximum diameter.

(3-2) Application Step The step of applying the aqueous coating solution is preferably an in-line coating method applied during the production process of the film. More preferably, it is applied to the base film before the crystal orientation is completed. The solid content concentration in the aqueous 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. Coating amount of the aqueous coating solution The film coated with the aqueous coating solution is led to a tenter for orientation and heat setting, and heated there to form a stable film by a thermal cross-linking reaction. It becomes.

(Amount of application)
The coating amount when not dried (hereinafter abbreviated as wet coating amount) is preferably ² g / m ² or more and less than 10 g / m ² . In order to obtain the designed dry coating amount (the coating amount of the final coating layer) when the wet coating amount is less than 2 g / m ² , it is necessary to increase the solid content concentration of the coating solution. 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 10 g / m ² or more, it is easily affected by the drying air in the drying furnace, and coating spots are likely to occur. In order to prevent defects due to dust adhesion, it is preferable to apply the coating liquid in a clean environment with a cleanness of class 5000 or less.

Moreover, it is preferable to manage the coating amount (solid content mass per unit area of the film) of the final coating layer to 0.005 to 0.20 g / m ² . In the prior art, if the coating amount is less than 0.05 g / m ^2, it is difficult to obtain sufficient adhesion. However, since the coating layer has a specific phase separation structure, a laminated film having excellent adhesion to the functional layer and the substrate can be obtained even when the coating amount is less than 0.05 g / m ^2. . If the coating amount is less than 0.005 g / m ² , the adhesion will be insufficient. When the coating amount is less than 0.05 g / m ^2, it is preferable to use particles having an average particle size of 60 nm or less. When the average particle diameter of the particles exceeds 60 nm, the particles easily fall off from the coating layer. When the particles are unevenly distributed in the polyurethane phase, the particles are unlikely to fall off if the coating amount is 0.005 g / m ² or more. On the other hand, when the coating amount exceeds 0.20 g / m ² , the polyurethane resin component that segregates on the surface of the coating layer increases, and the blocking resistance decreases.

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, when the coating layer is soft, it may be deformed during cutting. For simplicity, if the coating amount is known, the thickness can be converted from the density of the coating layer. For example, when the density of the coating layer is 1 g / cm ³ , the thickness corresponds to 1 μm if the coating amount is 1 g / m ² . For the density of the coating layer, the thickness of the coating layer is estimated by calculating the density of each material from the type of resin and particles constituting the coating layer, multiplying the density of each material by the mass ratio of the material, and obtaining the sum. be able to.

(3-3) Drying step In the method for producing a laminated thermoplastic resin film of the present invention, after the coating liquid is applied to the base film, the thinly coated film is dried. Generally, when the coating film is dried after the coating solution is applied, it is often dried using a preheating zone of a tenter. In this case, although it depends on the size of the film-forming equipment and the traveling speed of the film, it generally takes at least about 5 seconds from application to drying. During this time, the balance between water and alcohol, which are solvents for the coating solution, is lost, and the highly hydrophilic polyurethane component tends to segregate on the surface of the coating layer. Therefore, in the finally obtained laminated thermoplastic resin film, it becomes difficult to control the PEs surface fraction on the surface of the coating layer to a specific range. In the present invention, it is important to place a drying oven (pre-dryer) dedicated to drying the coating film as close as possible to the exit of the coating device in the film traveling direction, and to dry the coating liquid immediately after coating the polyester film. It is.

  In the drying furnace, the temperature of the drying air on the coated surface is preferably 120 ° C. or higher and lower than 150 ° C. The wind speed is preferably 30 m / second or more. A more preferable drying temperature is 130 ° C. or higher and lower than 150 ° C. When the drying temperature is less than 120 ° C. or the wind speed is less than 30 m / sec, the drying speed becomes slow, the balance between water and alcohol as the solvent of the coating solution is lost, and the ratio of water is relatively likely to increase. Therefore, a highly hydrophilic polyurethane component is segregated on the surface of the coating layer, and it becomes difficult to obtain the PEs surface fraction defined in the present invention in the finally obtained laminated thermoplastic resin film. On the other hand, when the drying temperature is 150 ° C. or higher, crystallization of the substrate film is likely to occur, and the frequency of breakage during transverse stretching increases.

  Moreover, in the said drying furnace, it is preferable to dry for 0.1 to 5 second, maintaining temperature at 120 to 150 degreeC. The drying time is more preferably 0.5 to 3 seconds. When the drying time is less than 0.1 seconds, the coating film is not sufficiently dried, and the roll is contaminated with an insufficiently dried coating surface when passing through the roll disposed between the drying process and the transverse stretching process. It becomes easy to do. On the other hand, if the drying time exceeds 5 seconds, crystallization of the substrate film is likely to occur, and the frequency of breakage during transverse stretching increases.

  After drying the coating film at a temperature of 120 ° C. or higher and lower 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 surface temperature of the laminated film leaves the drying furnace with a high 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 shrinkage of the film.

  When the wind speed in the drying furnace is usually 30 m / second or more, drying unevenness is likely to occur because strong drying air is applied to the undried coated surface in the drying furnace. However, in the present invention, it is possible to perform at a wind speed of 30 m / sec or more by exhausting the air volume equal to or greater than the air volume to be blown out of the drying furnace. It is also important that the exhaust air flow to the opposite side of the coater to prevent unevenness on the coating surface due to the exhaust air at the coater.

  It is important that the transit time of the film from immediately after coating to entering the drying furnace is less than 2 seconds, preferably less than 1.5 seconds. If the time from application to entry into the drying oven is 2 seconds or longer, the balance between water and alcohol, which are the solvent of the coating solution, is lost during this time, and this makes it easier for the highly hydrophilic polyurethane component to segregate on the surface of the coating layer. . Therefore, it becomes difficult for the laminated thermoplastic resin film finally obtained to have a PEs surface fraction on the surface of the coating layer within a specific range.

  In order to maintain the passage time of the film from immediately after coating to entering the drying furnace to less than 2 seconds, it is necessary to appropriately select the traveling speed of the film, but it is preferable to make the coater and the drying furnace inlet as close as possible. . In the drying furnace, it is preferable to use air cleaned with a HEPA filter in order to prevent dust from being mixed in from the drying air. As the HEPA filter used at this time, a filter having a performance of cutting 95% or more of dust having a nominal filtration accuracy of 0.5 μm or more is preferably used.

  The drying step is preferably composed of a drying zone divided into so-called 2 to 8 zones in which drying temperature and drying time conditions are sequentially changed. Particularly preferably, a multistage drying apparatus divided into 3 to 6 zones is employed. For example, when the coating solution is applied to one or both sides of a uniaxially oriented thermoplastic resin film and dried in a multistage drying furnace disposed directly above the coater, the following method is suitable.

  For example, when drying is performed in four stages, drying is performed in a drying furnace divided into four drying zones. 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, and in the third drying zone, the temperature is 35 to 55 ° C. In the fourth drying zone for 0.1 to 4 seconds, a method of drying at a temperature of 25 to 35 ° C. for 0.1 to 4 seconds can be mentioned.

  The numerical range of the drying conditions varies somewhat depending on the solid content concentration of the coating solution, and is not limited to the above typical conditions. Furthermore, when performing hot air drying, it is important that the air volume also changes at each stage.

For example, the following method is suitable.
In the first drying zone, the wind speed of the drying air to 20 to 50 m / sec, the supply air volume of the drying air 100-150 ³ / sec, setting the exhaust air volume to 150 to 200 m ³ / sec. From the second drying zone to the fourth drying zone, the supply air volume is set to 60 to 140 m ³ / sec, and the exhaust air volume is set to 100 to 180 m ³ / sec. In any drying zone, set so that the drying air does not flow to the coater side, and then grip the end of the film with a clip to make a hot air zone at a temperature of 100 to 140 ° C. and a wind speed of 10 to 20 m / sec. Guide and stretch 2-6 times in the width direction.

  Further, while maintaining the temperature at 120 to 150 ° C., the drying temperature and the total drying time may be appropriately adjusted for 0.1 to 5 seconds, preferably 0.5 to less than 3 seconds. Each step (zone) in the drying process is determined appropriately at the manufacturing site in consideration of various 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. The appropriate value can be determined.

(3-4) Heat setting treatment step In the method for producing a laminated thermoplastic resin film of the present invention, the transverse stretching step, the heat setting treatment step, and the cooling step are continuously divided into 10 to 30 zones, and each zone is It is partitioned so that the temperature can be controlled independently, and is designed so that there is no sudden temperature change between the zones. In particular, a rapid temperature change between adjacent zones can be suppressed by raising the temperature stepwise from the latter half of the transverse stretching zone to the heat setting maximum temperature setting zone. In the present invention, when producing a laminated thermoplastic resin film having a specific phase separation structure on the surface of the coating layer, temperature control is very important particularly in the drying step and the heat setting treatment step. Moreover, in order to form a crosslinked structure in the resin constituting the coating layer, the temperature in the heat setting process is very important, and this temperature greatly affects the crosslinking reaction rate. Hereinafter, the embodiment will be described in detail.

  As described above, in the heat setting treatment step of the present invention, the heat treatment condition determines the phase separation state of the coating layer. That is, the maximum temperature in the heat setting process, the time required to reach the maximum temperature, and the time required to reach the maximum temperature in the heat setting process from the temperature at which the phase separation of the coating layer starts to proceed significantly. It is important to set appropriately.

  The temperature in each heat setting zone in the heat setting treatment step may be appropriately set within a temperature range of 100 to 260 ° C., although there are some differences depending on the type of constituent resin of the thermoplastic resin film of the substrate. Hereinafter, a case where polyethylene terephthalate, which is a typical thermoplastic resin, is used as a base film will be described as an example.

  The maximum temperature in the heat setting treatment step is preferably controlled at 210 to 240 ° C, more preferably the lower limit is 225 ° C and the upper limit is 235 ° C. In general, heat fixing is performed at a relatively high temperature of 210 to 240 ° C. in the initial stage of the heat setting treatment, and the temperature is often gradually decreased to 100 to 200 ° C. in the subsequent stage.

  When the maximum temperature in the heat setting treatment step is less than 210 ° C., it is difficult to form a microphase separation structure or a nanophase separation structure in the coating layer. Therefore, it becomes difficult to obtain sufficient adhesion between the base material and the functional layer, which can withstand the peeling of the interface due to the impact during high-speed cutting, which is required in recent years. Furthermore, the thermal contraction rate of the obtained laminated film becomes large, which is not preferable.

  In addition, when the maximum temperature in the heat setting process exceeds 240 ° C., the PEs surface fraction of the coating layer surface increases, and the hard coat layer, the diffusion layer, the prism layer, and the printed layer printed with the ultraviolet curable ink Etc., the adhesion to the functional layer tends to decrease. Furthermore, since the time required to reach the maximum temperature of the heat setting treatment from the temperature at which the phase separation of the coating layer starts to proceed remarkably increases, the width of the narrowest part of the polyester phase mainly composed of the copolyester resin Will be dotted with locations exceeding 1 μm. As a result, a part having poor adhesion is generated on a functional layer such as a hard coat layer, a diffusion layer, a prism layer, or a printing layer printed with ultraviolet curable ink locally, and macroscopic peeling starts from that part. May lead to.

Specifically, the time required to reach the maximum temperature of the heat setting treatment from the temperature at which the phase separation of the coating layer starts to proceed remarkably is preferably set as follows.
In the present invention, the passage time of the film from the temperature setting zone where the phase separation of the coating layer starts to proceed remarkably to the maximum temperature setting zone inlet of the heat setting treatment step is preferably 3 seconds or more and less than 20 seconds, particularly Preferably it is 4 seconds or more and less than 15 seconds.

  If the passage time is less than 3 seconds, the time for developing the phase separation structure defined in the present invention may be insufficient. On the other hand, when the passage time is 20 seconds or more, the phase separation proceeds excessively, and the thinnest portion of the phase mainly composed of the copolyester resin tends to be dotted with portions having a width exceeding 1 μm. As a result, a portion having poor adhesion to a functional layer such as a hard coat layer, a diffusion layer, a prism layer, or a printing layer printed with UV ink is locally generated, which may lead to macroscopic peeling starting from that portion. is there.

  In the present invention, the temperature at which the phase separation of the coating layer starts to proceed remarkably is estimated to be about 200 ° C. within the range of the coating liquid composition shown in the examples of the present invention. However, the temperature is naturally not limited to this temperature because it varies depending on the resin component of the coating layer.

The heat setting process will be described more specifically.
In general, the transverse stretching process, heat setting process, and cooling process are divided into 10 to 30 zones in the tenter in order to suppress a rapid temperature change in each adjacent zone, and temperature control is independently performed in each zone. Has been made. In particular, in the zone set to the maximum temperature of the heat setting treatment process from the latter half of the transverse stretching zone, the temperature of each zone is increased stepwise with respect to the film advancing direction, and the temperature between each heat setting zone is rapidly increased. It is preferable that no significant temperature change occurs.

  In the present invention, it is important to quickly and uniformly raise the passage time of the film from the temperature setting zone where the phase separation starts to proceed remarkably to the maximum temperature setting zone entrance of the heat setting treatment step. . In order to quickly raise the temperature, a method of increasing the heat transfer efficiency in each heat setting zone, for example, a method of increasing the speed of hot air blown to the film is effective. However, in this method, generally, temperature spots are likely to occur, so if spots occur in the phase separation state of the coating layer, or foreign matters such as oligomers slightly adhering to the inside of the apparatus in the heat setting zone soar, In some cases, the soared foreign matter adheres to the film and leads to optical defects.

  On the other hand, if the wind speed is too low, a sufficient heating rate cannot be obtained. Therefore, in the present invention, the wind speed is preferably set to 10 m / second or more and less than 20 m / second. In order to quickly and uniformly raise the temperature of the laminated film, it is effective to arrange the nozzles for blowing hot air at relatively short intervals of 500 mm or less. In the case where the nozzle spacing for blowing hot air is set to 500 mm or less, for example, when the nozzle spacing is set to 300 mm, 350 mm, or 400 mm, it is disadvantageous for equipment maintenance, but it is important for completing the present invention. . The number of nozzles per zone corresponding to one stage is about 6 to 12, and the number is determined in consideration of the state of the nozzle interval, the amount of ventilation, and the ventilation time. In addition, the wind speed described by this invention means the wind speed in the film surface which faced the hot air blowing nozzle exit, and was measured using the thermal-type anemometer (Nippon Kanomax make, Anemomaster model 6161).

1 shows a preferred embodiment of the heat setting treatment step of the present invention.
The heat setting treatment step is continuously divided into a plurality of heat setting zones, and each zone is partitioned so that the temperature can be controlled independently. The heat setting zone is divided into a process in which 2 to 10 steps of heat setting zones are continuously arranged, preferably 4 to 8 steps, and the temperature control management of the laminated film is performed in the heat setting zone divided into multiple stages. It is preferable to

  For example, in the case of a polyester film having a coating layer, the film is sequentially passed through a heat setting zone divided into six stages as described below, and a heat setting process is performed with a subtle temperature difference at each stage. There is a method of trimming the uncoated portions at both ends. The heat setting treatment temperature is 200 ° C. in the first heat setting zone, 225 ° C. in the second heat setting zone, 230 ° C. in the third heat setting zone, 230 ° C. in the fourth heat setting zone, and in the fifth heat setting zone. 210 ° C., 170 ° C. in the sixth heat setting zone, and 120 ° C. in the seventh heat setting zone. In addition, 3% relaxation treatment is performed in the width direction in the sixth heat fixing zone.

  Said stage corresponds to one heat setting zone. Thus, it is preferable to give a subtle temperature difference to the temperature of the heat setting zone of each stage, that is, to give a temperature difference of about 5 to 40 ° C. The setting of this temperature difference is arbitrarily determined in consideration of various factors such as the running speed of the thermoplastic resin film having the coating layer, the air volume, and the thickness of the coating layer.

  When used as a base film of an optical functional film or optical functional sheet such as a lens film or a diffusion plate, the film length is usually at least 1000 m or more, even if the film thickness is a relatively thick film of 100 μm or more. In some cases, a prism layer or a diffusion layer is laminated in a form wound up in a roll of 2000 m or more.

  In the present invention, when the area ratio (PEs surface fraction) of the polyester phase A (indicating a dark hue in the phase image) on the surface of the coating layer is measured at intervals of 100 m in the longitudinal direction of the film, the surface of the coating layer in the longitudinal direction The difference between the maximum value and the minimum value of the PEs surface fraction is preferably 15% or less, more preferably 10% or less. By setting the difference between the maximum value and the minimum value of the PEs surface fraction on the surface of the coating layer in the longitudinal direction to 15% or less, a laminated thermoplastic resin film roll having stable adhesion and blocking resistance can be obtained. .

  In order to control the difference between the maximum value and the minimum value of the PEs surface fraction on the surface of the coating layer in the longitudinal direction to 15% or less, film formation such as the composition of the coating solution, coating conditions, drying conditions, and heat setting conditions It is important to keep the conditions constant when manufacturing the laminated thermoplastic film roll of the present invention. However, in particular, the ratio of the mixed solvent used in the coating solution is likely to fluctuate, and it is important to keep the ratio of the mixed solvent constant in order to reduce the fluctuation of the PEs surface fraction in the longitudinal direction of the film roll. In the present invention, for example, the fluctuation range of the PEs surface fraction can be controlled to 15% or less by the following means. The means for keeping the ratio of the mixed solvent constant is not limited to the following method.

  Increasing the capacity of the circulation tank (13 in FIG. 7) relative to the capacity of the coating solution receiving tray (11 in FIG. 7) is effective in stabilizing the concentration ratio of the mixed solvent. Specifically, as shown in FIG. 7, when the capacity of the receiving tray of the coating liquid is 1, the ratio of the capacity of the circulation tank is preferably 10 or more, particularly preferably 50 or more. When the volume ratio (capacity of the circulation tank / capacity of the coating liquid tray) is less than 10, that is, the capacity of the circulation tank is too small, the variation in the concentration ratio of the mixed solvent tends to increase.

  Furthermore, when the capacity of the circulation tank is 1, the ratio of the capacity of the preparation tank (14 in FIG. 7) is preferably 10 or more, particularly preferably 20 or more. Thereby, when supplying a coating liquid from the tank for preparation to the tank for circulation, the capacity of the tank for circulation can be always kept constant during operation.

  Further, increasing the accuracy (roundness and cylindricity) of the applicator roll in the coating apparatus is also effective in reducing the fluctuation of the PEs surface fraction in the longitudinal direction of the film roll.

  The roundness of the applicator roll is expressed by the difference between the radii of two concentric circles by the minimum area method determined by using a recorded roundness measuring instrument as shown in JIS B 0621. It is an indicator. The unit of roundness of the roll is mm. In addition, the cylindricality of the applicator roll can be measured in various measurement planes over the entire length by moving the stand with a measuring instrument on the surface plate in the axial direction and placing the probe on the upper surface of the cylinder. This is an index represented by ½ of the maximum difference in reading at the time of measurement. The unit of cylindricity is mm.

  In the present invention, by improving the roll accuracy (roundness and cylindricity), variation in the thickness of the coating layer in the length direction can be reduced. Specifically, the roll accuracy (roundness and cylindricity) is preferably less than 5/1000 mm.

  Further, when applying the coating liquid, the surface finish of each roll of the reverse coater is set to 0.3 S or less, and the accuracy (roundness and cylindricity) of the applicator roll and the metering roll is less than 5/1000 mm. By setting it to 1000 mm or more, fluctuations in the wet coating amount can be suppressed, and variations in the coating film can also be suppressed. It is preferable to use a coating roll in which the accuracy (roundness and cylindricity) of the applicator roll and the metering roll is 3/1000 mm.

  Further, by setting the tension of the film to 4000 to 10,000 N / raw width (raw width is 1 to 2 m), the flatness of the film is maintained on an industrial scale, and the transfer amount of the coating liquid becomes uniform. The tension of the film varies depending on the thickness of the film, and the flatness is maintained by applying a lower tension to a relatively thin film.

  If the tension of the film exceeds 10,000 N / raw width, the original film may be deformed or broken. On the other hand, if the tension of the film is less than 4000 N / raw width, the flatness of the film at the time of coating may be insufficient or the film may meander. As a result, the transfer amount of the coating liquid becomes non-uniform in the length direction of the film, and the variation in the thickness of the coating layer becomes larger due to the large variation in the wet coating amount of the film.

  Moreover, in order to control the difference between the maximum value and the minimum value of the PEs surface fraction in the width direction of the film roll to 10% or less, it is important to reduce the variation in the thickness of the coating layer with respect to the width direction of the film roll. is there. For this purpose, it is effective to improve the planarity in the width direction during coating. Specifically, just after coating with a reverse roll, only the both end faces of the film are gripped using a pinch roll (16 in FIG. 7). By causing the pinch roll to grip both ends of the film, the flatness in the width direction of the film is improved on an industrial scale, and the wet coating amount in the width direction of the film is stabilized. Thereby, the dispersion | variation in the application layer of the width direction of a film roll can be reduced. When the both ends of the film are not gripped with a pinch roll, the wet coating amount in the width direction and the length direction of the film varies greatly, and the variation in the thickness of the coating layer also increases.

  Next, although the structure of a laminated thermoplastic resin film of this invention, an effect, and a manufacturing method are demonstrated using an Example and a comparative example, this invention is naturally not limited to these Examples. Moreover, the following method was used for the physical property and evaluation of each film in an Example.

(1) PEs surface fraction (1-1) Evaluation of phase separation structure The phase separation structure of the coating layer was evaluated using a scanning probe microscope (SPI3800N system / SPA300, manufactured by SII Nanotechnology). The mode (phase mode) was performed. In the phase image, the larger the phase lag, the brighter the color image, and the smaller the phase lag, the darker the image. A small phase lag means that it is harder or has a relatively smaller adsorption force than the other phases. In the coating layer of the laminated thermoplastic resin film of the present invention, the dark color phase is the polyester phase A, and the light color layer is the polyurethane layer.

  The measurement principle of the phase measurement mode in the scanning probe microscope can be found on the website of STS Nanotechnology Co., Ltd. (HTP: // WW. It is described in the PDF file of “1. Phase measurement by SPM” in the Phase column in “1-2. Application (by mode)” of “OB.

  The cantilever used for the measurement was mainly DF3 (spring constant: about 1.6 N / m), and a new one was always used in order to prevent a decrease in sensitivity and resolution due to probe contamination. The scanner used was FS-20A. Further, the observation was performed with a resolution of 512 × 512 pixels or more, and the observation field of view was 5 μm × 5 μm. Measurement parameters such as the amplitude attenuation rate of the cantilever, the scanning speed, and the scanning frequency at the time of measurement were set to conditions under which line scanning was performed and observation was possible with the highest sensitivity and resolution.

  The phase mode image (bitmap format, 512 × 512 pixels) obtained as described above is read into image processing software (manufactured by Adobe, Photoshop ver. 7.0) and displayed on the display so that the image size is 205 mm × 205 mm. (See FIGS. 1 and 8). Next, a black line was drawn at the boundary between the light hue and the dark hue with the pencil tool (master diameter: 3 px) of the same software to clarify the boundary between the two phases (see FIGS. 2 and 9). Furthermore, using the paint tool of the same software, the dark hue was painted black and the light hue was painted white and binarized (see FIGS. 3 and 10). At this time, a dark color portion having a size on the screen and having a diameter of 2 mm or less in the light hue was determined to be particles unevenly distributed in the light hue, and was painted white. For example, when silica particles are used, it is confirmed that they are unevenly distributed in the light color layer.

(1-2) Measurement of PEs surface fraction (1-2-1) Image analysis method With this software, luminance (black, white) is plotted on the horizontal axis, and frequency is plotted on the vertical axis. A histogram was displayed, and the area ratio of the black portion was determined and used as the PEs surface fraction.

(1-2-2) Paper Weight Method The PEs surface fraction can be measured by using a paper weight method in addition to the image analysis method. The measurement procedure is as follows.
The phase mode image obtained as described above was stored as a digital image in bitmap format. Next, this image was printed out on A4 quality paper using a printer (Xerox, DocuPrint C830). For the output image (200 mm × 200 mm), the boundary between the light hue and the dark hue in the image was clarified with a 4B pencil in a bright room under 500 lux illumination by visual confirmation. At this time, since the dark hue having a diameter of 0.1 μm or less existing in the bright hue is confirmed to be particles contained in the coating layer unevenly distributed in the bright hue, no boundary line is drawn. , Included in light hue. After that, the boundary line where the light hue and the dark hue are clarified is divided by cutting with a cutter knife, and the mass of the light hue (polyurethane layer (B)) and dark hue (polyester phase A) paper is measured. The ratio of the mass of the dark hue (polyester phase A) to the total mass of the paper of the layer and the dark color layer was determined in units of%, and was used as the PEs surface fraction.

(1-2-3) Variation width of PEs surface fraction (difference between maximum value and minimum value)
(A) Longitudinal direction of film roll A laminated thermoplastic resin film roll having a length of 1000 m or more and a width of 50 mm or more is unwound, and the polyester phase A on the surface of the coating layer (dark color in the phase image) in the longitudinal direction (MD) of the film. Phase ratio) (PEs surface fraction) was measured at the following locations, and the difference between the maximum value and the minimum value of the obtained PEs surface fraction was determined.
The measurement of the PEs surface fraction on the surface of the coating layer is 1 at 2 m or less on the inner side of the first end when one end of the steady region where the film properties are stable is the first end and the other end is the second end. The second measurement is performed at a distance of 2 m or less on the inner side of the second end portion, and at every 100 m from the first measurement point.

(B) Width direction of film roll A laminated thermoplastic resin film roll having a length of 1000 m or more and a width of 50 mm or more is unwound, and the laminated thermoplastic resin film roll is unwound in the width direction (TD) of the film. Is divided into four equal parts in the width direction, and at each central portion, the area ratio (PEs surface fraction) of the polyester phase A (indicating a dark hue in the phase image) on the surface of the coating layer is measured. The difference between the maximum value and the minimum value of the PEs surface fraction was determined. You may perform this measurement with the jumbo roll before slitting the width direction of a film to a small width size.

(2) Presence / absence of locations where the width of the polyester phase A exceeds 1 μm at the minimum In the above-mentioned phase mode image, the width in the minor axis direction of the polyester phase A mainly composed of a copolyester resin is measured at 10 different measurement locations. The thickness of the thinnest part was examined for the presence of over 1 μm.

(3) Fractal dimension A phase mode image (bitmap format, 512 × 512) obtained by the phase measurement mode (phase mode) using the above-described scanning probe microscope (manufactured by SII Nanotechnology, SPI3800N system / SPA300). Pixel) was read by image processing software (manufactured by Adobe, Photoshop ver. 7.0) and displayed on the display so that the size of the image was 205 mm × 205 mm (see FIGS. 1 and 8). Next, a black line was drawn at the boundary between the light hue and the dark hue with the pencil tool (master diameter: 3 px) of the same software to clarify the boundary between the two phases (see FIGS. 2 and 9). At this time, a dark color portion having a size of 2 mm or less in the bright hue with a size on the screen was determined to be a particle unevenly distributed in the bright hue, and the operation for drawing the boundary line was not performed on this portion. For example, when silica particles are used, it is confirmed that they are unevenly distributed in the light color layer.

  An image with a clear boundary line was saved as a bitmap format image, and a fractal dimension analysis was performed by the box counting method. The obtained fractal dimension value was used as an index indicating the complexity of the phase separation boundary line. For the analysis by the box counting method, software AT-Image ver3.2 was used. Specifically, the saved bitmap image was opened on image analysis software (AT-Image ver. 3.2), and binarization processing by luminance histogram was performed from image extraction on the menu (see FIG. 6). The threshold value for binarization was 8. For the binarized image, the fractal dimension was selected from the image measurement on the menu, and the fractal dimension was obtained. At this time, for the calculation of the fractal dimension by the method of least squares, the counting result of a box having a side length of 6 pixels to 63 pixels was used.

  Note that the fractal dimension analysis by the box counting method is a known method, and using other image analysis software or program for the dimension analysis has other same functions as long as the reproducibility of the analysis result is sufficiently obtained. Software may be used. Examples of other software include image analysis such as “Fractal Analysis System Version 3.33 made by National Institute of Agricultural Sciences, Livestock Pasture Research Institute”, “PopImaging Ver. 3.40 made by Digital Being Kids”, etc. Software.

(4) Measurement of haze Based on JIS K7136, using a haze meter (Nippon Denshoku make, NDH2000), haze was measured about three different places of a film sample, and the average value was used.

(5) Adhesiveness with photocurable acrylic hardcoat layer (5-1) Adhesiveness with solvent-diluted photocurable acrylic hardcoat layer Hard coating agent (Daiichi Seika) on the coating layer surface of the film sample Manufactured by Seika Beam EXF01 (B)), 50 parts by mass of toluene, 25 parts by mass of toluene, and 25 parts by mass of methyl ethyl ketone were mixed, and a well-stirred coating agent was applied with a wire bar and dried at 70 ° C. for 1 minute to remove the solvent. A hard coat film having a hard coat layer with a thickness of 3 μm was obtained under the conditions of 200 mJ / cm ² , irradiation distance 15 cm, and traveling speed 5 m / min with a high-pressure mercury lamp.

A surface opposite to the hard coat layer of the obtained hard coat film was attached to a glass plate having a thickness of 5 mm to which a double-sided tape was attached. Next, 100 grid-like cuts that penetrated the hard coat layer and the coating layer to reach the base film were made using a cutter guide with a gap interval of 2 mm. Next, an adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) was attached to the cut-like cut surface. The air remaining on the interface at the time of pasting was pushed with an eraser to bring it into close contact, and then the adhesive tape was peeled off vigorously and vertically. Further, a new adhesive tape was applied in the same manner, and it was peeled off in a vertical direction. This adhesive tape peeling operation was repeated a total of 10 times, and the adhesion was visually determined from the following formula. In addition, what is partially peeled within one square is also included in the number of peeled.
Adhesiveness (%) = (1-number of cells peeled off / 100) × 100

(5-2) Adhesiveness with solvent-free photo-curing acrylic hard coat layer On a 5 mm thick glass plate kept clean, hard coat agent (Daiichi Seika Co., Ltd., Seika Beam EXF01 (B)) approx. 5 g was placed and overlapped so that the coating layer surface of the film sample was in contact with the hard coating agent, and the hard coating agent was pressure-bonded so as to be extended from above the film sample by a manual load rubber roller having a width of 10 cm and a diameter of 4 cm. Next, from the film surface side, the hard coat layer was cured by irradiating ultraviolet rays with a high pressure mercury lamp under conditions of 500 mJ / cm ² , an irradiation distance of 15 cm, and a running speed of 5 m / min.

Subsequently, the film sample which has a hard-coat layer was peeled off from the glass plate, and the hard-coat film was obtained. The surface opposite to the hard coat layer of the hard coat film was attached to a glass plate having a thickness of 5 mm to which a double-sided tape was attached. Next, 100 grid-like cuts that penetrated the hard coat layer and the coating layer to reach the base film were made using a cutter guide with a gap interval of 2 mm. Next, an adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) was attached to the cut-like cut surface. The air remaining on the interface at the time of pasting was pushed with an eraser to bring it into close contact, and then the adhesive tape was peeled off vigorously and vertically. Further, a new adhesive tape was applied in the same manner, and it was peeled off in a vertical direction. This adhesive tape peeling operation was repeated a total of 10 times, and the adhesion was visually determined from the following formula. In addition, what was peeled partially even with one square was made into the number which peeled.
Adhesiveness (%) = (1-number of cells peeled off / 100) × 100

(6) Blocking resistance The coating layer surfaces of two film samples were overlapped, and a pressure of 1 kgf / cm ² was adhered thereto in an atmosphere of 50 ° C. and 60% RH for 24 hours, and then peeled off. The state was judged according to the following criteria.
○: The coating layer is not transferred and can be peeled lightly. Δ: The peeling sound is generated and the coating layer is partially transferred to the other surface. ×: The two films are fixed and cannot be peeled or peeled. Even if the base polyester film is cleaved

(7) Hardness index of coating layer The coating layer of the film sample was scratched using a surface property measuring instrument (manufactured by Shintoa Chemical Co., HEIDON 14). At this time, a genuine needle having a sapphire with a radius of 75 μm at the tip was used as a scratching needle. The traveling speed of the needle was 150 mm / min, and the load was 5 gf.

  The surface shape of the scratch attached to the coating layer was measured under the following conditions using a three-dimensional non-contact surface shape measuring device (Micromap, Micromap 550), and profile mode data was displayed. Representative examples are shown in FIGS. From the obtained scratch shape data, an average value of 30 height differences between adjacent convex and concave portions was obtained and used as the hardness index of the coating layer. At this time, protrusions having a height of 30 nm or more were judged to be protrusions caused by particles contained in the coating layer or the thermoplastic resin film, and were excluded. Further, protrusions having a height of 1 nm or less were excluded because of the influence of noise.

(Measurement condition)
-Profile mode: Wave mode-Objective lens: 10x-Resolution: 160 x 160 pixels-Measurement length: 207.1 nm

Example 1
(1) Preparation of coating solution The coating solution used in the present invention was prepared according to the following method. A reaction vessel was 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 over 3 hours. Next, 6.0 parts by mass of 5-sodium sulfoisophthalic acid was added, and esterification was performed at 240 ° C. over 1 hour, and then at 250 ° C. under reduced pressure (10 to 0.2 mmHg) over 2 hours. A polycondensation reaction was performed to obtain a copolymerized polyester resin having a number average molecular weight of 19,500 and a softening point of 60 ° C.

  7.5% by mass of a 30% by mass aqueous dispersion of the obtained copolyester resin (A) and a 20% by mass aqueous solution of a self-crosslinking polyurethane resin (B) containing an isocyanate group blocked with sodium bisulfite. 11.3 parts by mass (Daiichi Kogyo Seiyaku Co., Ltd., Elastolon H-3), 0.3 parts by mass of Elastolone Catalyst (Daiichi Kogyo Seiyaku, Cat 64), 39.8 parts by mass of water and 37 isopropyl alcohol 4 parts by mass were mixed. Furthermore, colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle) as 0.6 parts by mass of 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFuck F142D) 2.3 mass parts of a 20 mass% aqueous dispersion having a diameter of 40 nm), and 3.5 mass% aqueous dispersion of dry process silica (Nippon Aerosil, Aerosil OX50; average particle diameter 200 nm, average primary particle diameter 40 nm) as particles B 0.5 parts by mass of the liquid was added. Next, the pH of the coating solution is adjusted to 6.2 with a 5% by weight aqueous sodium bicarbonate solution, and the solution is precisely filtered with a felt type polypropylene filter having a filtration particle size (initial filtration efficiency: 95%) of 10 μm to prepare coating solution A. did. In addition, the said surfactant used what was pre-processed by the following method.

  Isopropyl alcohol (IPA) was added to the above-mentioned surfactant, and heated and dissolved in a 30 ° C. hot bath to prepare a 15 mass% surfactant IPA solution. This solution was filtered with a quantitative filter paper (Advantech Toyo, No. 5C) to remove insolubles and dust in the solution. After filtering the said solution, this solution was put into the airtight glass container, and it left still for 24 hours in a 0 degreeC freezer. After 24 hours, the solution containing the precipitated solid was subjected to suction filtration using the quantitative filter paper. The solid on the filter paper was vacuum-dried to obtain a solid, diluted with water to a 10% by mass aqueous solution, and used as a pretreated surfactant.

  The surfactant obtained by the pretreatment was analyzed with a TLC-coated plastic sheet (manufactured by Merck, silica gel 60) using methanol as a developing solution. As a result of coloring the sample spot with iodine vapor, it was confirmed that a spot corresponding to polyethylene glycol was not detected.

(2) Production of laminated polyester film Polyethylene terephthalate (PET) resin pellets containing no particles and having an intrinsic viscosity of 0.62 dl / g as a raw material polymer were dried under reduced pressure (1 Torr) at 135 ° C. for 6 hours. Next, the dried PET resin pellets were supplied to an extruder, melted and 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. to obtain a cast film. At this time, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter medium for removing foreign substances in the molten resin.

  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 peripheral speed difference to obtain a uniaxially oriented PET film. Next, the coating solution A was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency: 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method. At this time, the application roll and the metalling roll of the coater were rolls having a surface with an ultra-hard chrome plating finish of 0.2 S or less and a roundness and cylindricity of 3/1000 mm.

Then, in a drying furnace divided into four zones arranged just above the coater, the first zone (135 ° C. for 1.0 second), the second zone (65 ° C. for 2.2 seconds), the third zone (40 ° C. 1.8 seconds), and the coated surface was dried in the fourth zone (1.8 seconds at 30 ° C.). The coating amount was 0.08 g / m ² as the final solid content. The transit time of the film from application to the film to the entrance of the drying oven was 0.8 seconds. Further, at this time, the wind speed of the drying air in the first zone is 30 m / sec, the supply air volume of the drying air is 130 m ³ / sec, the exhaust air volume is 170 m ³ / sec, and the supply air volume from the second zone to the fourth zone Was set to 100 m ³ / sec and the exhaust air flow was set to 150 m ³ / sec so that dry air did not flow to the coater side. The tension of the film was 7000 N / raw fabric, and both ends of the film were held with pinch rolls from the coating to the drying furnace inlet.

Furthermore, in the coating at this time, a coating apparatus in which the ratio of the capacity of the coating liquid tray, the capacity of the circulation tank, and the capacity of the preparation tank has the following relationship was used.
(A) Ratio of the volume of the coating liquid tray to the volume of the circulation tank = 1/50
(B) Capacity ratio of the circulation tank to the mixing tank = 1/40

  Subsequently, while holding the edge of the film with a clip, the film was guided to a hot air zone having a temperature of 120 ° C. and a wind speed of 15 m / sec, and stretched 4.3 times in the width direction. Next, while maintaining the width stretched in the width direction, the first heat setting zone (temperature: 200 ° C.), the second heat setting zone (temperature: 225 ° C.), and the third heat setting zone (temperature: 230 ° C.) , 4th heat setting zone (temperature: 230 ° C), 5th heat setting zone (temperature: 210 ° C), 6th heat setting zone (temperature: 170 ° C), 7th heat setting zone (temperature: 120 ° C) sequentially And let it pass. Note that a relaxation treatment of 3% in the width direction was performed in the sixth heat setting zone. Next, the uncoated portions at both ends of the film are trimmed, wound up by a winding device, further divided into four equal parts in the width direction, slitted, a width of 1000 mm, a film length of 1000 m, and a film thickness of 125 μm. A laminated polyester film roll was obtained. The hot air velocity in the heat fixing zone was 15 m / second, the passage time was 4.5 seconds in each zone, the nozzle interval for blowing hot air was 350 mm, and the number of nozzles per zone was 8.

  Table 4 shows the film properties and characteristics. In addition, the maximum value, minimum value, maximum value, minimum value of haze, maximum value and minimum value of adhesion to the hard coat layer in the longitudinal direction and width direction of the obtained laminated polyester film roll are shown. As shown in FIG. In addition, about the blocking resistance, it was (circle) in all the measurement points.

(Example 2)
In Example 1, a 10% by mass aqueous solution of a fluorine-based cationic surfactant (manufactured by Neos Co., Ltd., Aftergent 310) pretreated by the same method as in Example 1 was used as the surfactant used in the coating solution. A laminated polyester film was obtained in the same manner as in Example 1 except that the coating liquid B was changed.

(Example 3)
In the heat setting process of Example 1, the temperature of each heat setting zone is 190 ° C. in the first heat setting zone, 205 ° C. in the second heat setting zone, 220 ° C. in the third heat setting zone, and the fourth heat setting zone. A laminated polyester film was obtained in the same manner as in Example 1 except that the temperature was 220 ° C.

Example 4
In Example 1, the same method as in Example 1 was used 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 C, which was changed to 60/40. A polyester film was obtained.
(Preparation of coating liquid C)
9.0 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 1, and 9.0% by mass of a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 1. Part, 0.3 parts by mass of elastolone catalyst (Daiichi Kogyo Seiyaku, Cat64), 40.6 parts by mass of water, and 37.3 parts by mass of isopropyl alcohol were mixed. Furthermore, the surfactant aqueous solution used in Example 1 was 0.6 parts by mass, and a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A was 2.3. 0.5 parts by mass of a 3.5 mass% aqueous dispersion of dry process silica (manufactured by Nippon Aerosil Co., Ltd., Aerosil OX50; average particle diameter 200 nm, average primary particle diameter 40 nm) is added as mass parts and particles B, and 5 mass% sodium bicarbonate. The pH was adjusted with an aqueous solution, and the coating solution C was passed through a filter having a filtration performance of 5 μm and 1 μm in order.

(Example 5)
In Example 1, the same method as in Example 1 except that the mass ratio of the copolyester resin and the polyurethane resin in the coating liquid was changed to the following coating liquid D, which was changed to 40/60. A polyester film was obtained.
(Preparation of coating solution D)
6.0 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 1 and 13.5% by mass of a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 1 Part, 0.3 parts by mass of elastolone catalyst (Daiichi Kogyo Seiyaku, Cat64), 38.9 parts by mass of water, and 37.5 parts by mass of isopropyl alcohol 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 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, The pH was adjusted to 6.2 with a 5% by weight aqueous sodium bicarbonate solution, and a filter having a filtration performance of 5 μm and 1 μm was passed in this order to obtain a coating solution D.

(Example 6)
In Example 1, a laminated polyester film was obtained in the same manner as in Example 1 except that the coating amount was 0.12 g / m ² as the final solid content.

(Example 7)
In Example 1, the laminated polyester film was obtained by the same method as Example 1 except using the following coating liquid E which changed the compounding quantity of the surfactant in a coating liquid into 0.03 mass%. .
(Preparation of coating solution E)
In the preparation of the coating liquid of Example 1, 0.3 part by mass of a 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFuck F142D), 38.2 parts by mass of water, and Isopropyl alcohol was changed to 39.3 parts by mass.

(Example 8)
A laminated polyester film was obtained in the same manner as in Example 1 except that the following coating solution F was used except that the amount of the surfactant in the coating solution was changed to 0.10% by mass in Example 1. It was.
(Preparation of coating solution F)
In the preparation of the coating liquid of Example 1, 1.0 part by mass of a 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFuck F142D), 37.5 parts by mass of water, and Isopropyl alcohol was changed to 39.3 parts by mass.

Example 9
In Example 1, the film transit time from coating to the drying furnace inlet was 0.7 seconds, the drying time was 0.8 seconds, and the passage time of each zone in the heat setting treatment step was 3.5 seconds. A laminated polyester film was obtained in the same manner as in Example 1 except that was changed to 100 μm.

(Example 10)
In Example 1, the passage time of the film from the coating to the entrance of the drying furnace was 1.0 second, the drying time was 1.9 seconds, the passage time of each zone in the heat setting treatment step was 6.6 seconds, and the film thickness A laminated polyester film was obtained in the same manner as in Example 1 except that was changed to 188 μm.

(Example 11)
In Example 1, a laminated polyester film was obtained in the same manner as in Example 1 except that the pH of the coating solution was changed to the coating solution G adjusted to 7.9 using a 5% by mass sodium carbonate aqueous solution. .

(Example 12)
In Example 1, a laminated polyester film was obtained in the same manner as in Example 1 except that coating layers were applied to both sides of the uniaxially oriented polyester film. In addition, the passage time of the film from the application to the film to the entrance of the drying furnace was 0.8 second on one side and 1.0 second on the opposite side.

(Example 13)
In Example 1, a laminated polyester film was obtained in the same manner as in Example 1 except that the coating amount was 0.02 g / m ² as the final solid content.

(Example 14)
In Example 1, a laminated polyester film was obtained in the same manner as in Example 1 except that the coating liquid H that was not subjected to the surfactant pretreatment was used. The phase separation structure between the copolymerized polyester resin and the polyurethane resin by the scanning probe microscope (SPM) on the surface of the coating layer of the obtained laminated polyester film was discernable but could be somewhat unclear.

(Example 15)
In Example 1, a laminated polyester film was obtained in the same manner as in Example 1 except that the following coating liquid I was used in which the mass ratio of the dispersion medium (water / IPA) in the coating liquid was changed to 50/50. It was.
(Preparation of coating liquid I)
In preparation of the coating liquid of Example 1, 7.5 parts by mass of a 30% by mass aqueous dispersion of the polyester resin (A) used in Example 1 and 20 of the polyurethane resin (B) used in Example 1 were used. 11.3% by mass of a mass% aqueous solution, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku, Cat 64), 30.4 parts by mass of water, and 46.8 parts by mass of isopropyl alcohol 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 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, The pH was adjusted to 6.2 with a 5% by mass aqueous sodium bicarbonate solution, and a filter with a filtration performance of 5 μm and 1 μm was passed in this order to obtain a coating solution I.

(Example 16)
In Example 1, a laminated polyester film having a thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating liquid J, in which the pH of the coating liquid was changed to 4.6 with acetic acid, was used.

(Example 17)
In Example 1, a laminated polyester film was obtained in the same manner as Example 1 except that the coating liquid K was used in which the polyurethane resin (B) was changed to the following polyurethane resin. The polyurethane resin was obtained by the following method.
(Preparation of polyurethane resin)
93 polyester diols (OHV: 111.8 eq / ton, AV: 1.1 eq / ton) having a composition of adipic acid // 1.6-hexanediol / neopentyl glycol (molar ratio: 4 // 3/2) 22 parts by mass of xylylene diisocyanate were mixed and reacted at 95-100 ° C. for 1 hour under a nitrogen stream to obtain a urethane prepolymer (NCO / OH ratio: 1.50, free isocyanate group: theoretical value 3.29). Mass%, measured value 3.16 mass%).

  The resulting urethane prepolymer was then cooled to 60 ° C., 4.5 parts by weight of methyl ethyl ketoxime was added and reacted at 60 ° C. for 50 minutes to contain 1.3% by weight of free isocyanate and partially blocked A urethane prepolymer was obtained. Then, the said urethane prepolymer was cooled to 55 degreeC, the mixed solvent which consists of 9 mass parts of isopropyl alcohol and 140 mass parts of methanol was added, and it mixed uniformly. Next, 9.3 parts by mass of a 50% by mass aqueous sodium bisulfite solution and 5.4 parts by mass of a 30% by mass aqueous solution of N-methyltaurine were added and vigorously stirred. Water solubility began to appear after about 30 minutes, and free sodium bisulfite became almost zero after 2 hours, and the reaction was completed. Water was added thereto to obtain a 20% by mass aqueous solution that was cloudy and viscous.

(Comparative Example 1)
(1) Preparation of coating liquid L 33.7 parts by mass of dimethyl terephthalate, 20.0 parts by mass of dimethyl isophthalate, 9.1 parts by mass of 5-Nasulfodimethylisophthalate, 40.0 parts by mass of ethylene glycol 10.0 parts by mass of diethylene glycol Part, 0.049 parts by mass of calcium acetate · monohydrate, and transesterification was performed at 200 to 230 ° C. until the theoretical amount of methanol was distilled off. Next, 0.09 part by mass of orthophosphoric acid was added and polymerized at 280 ° C. under reduced pressure to obtain a copolymerized polyester resin.

Polyether containing a sulfonate group obtained by sulfonation of an ethylene oxide polyether starting from allyl alcohol with sodium metabisulfite (SO ₃ content: 8.3% by mass, polyethylene oxide content: 83% by mass), 192 parts by mass, poly 1013 parts by mass of tetramethylene adipate (number average molecular weight: 2,250) and 248 parts by mass of polypropylene oxide polyether (number average molecular weight: 550) initiated with bisphenol A were mixed and dehydrated at 100 ° C. under vacuum.

  The mixture is brought to 70 ° C., to which is added a mixture of 178 parts by weight of isophorone diisocyanate and 244 parts of hexamethylene-1,6-diisocyanate, and then the resulting mixture is heated from 80 ° C. until the isocyanate content is 5.6% by weight. The mixture was stirred at 90 ° C. The prepolymer was cooled to 60 ° C., and 56 parts by mass of biuret polyisocyanate obtained from 3 mol of hexamethylene diisocyanate and 1 mol of water, and 175 parts by mass of bischemitin obtained from isophorodiamine and acetone were added successively to form an aqueous polyurethane dispersion. Obtained.

  The copolymer polyester resin and the polyurethane water dispersion are blended so as to be 20 parts by mass and 80 parts by mass, respectively, and an aqueous dispersion having a solids concentration of 10% by mass is prepared. did. Note that particles and a surfactant were not blended in the coating solution.

(2) Production of laminated polyester film Polyethylene terephthalate resin pellets containing no particles and having an intrinsic viscosity of 0.66 dl / g as a raw material polymer are dried at 135 ° C. under reduced pressure (1 Torr) for 6 hours and then supplied to an extruder. Then, it was melt-extruded into a sheet at about 285 ° C. and rapidly cooled and solidified on a metal roll maintained at a surface temperature of 60 ° C. to obtain a cast film. At this time, as in the case of Example 1, a stainless sintered filter material having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter material for removing foreign matters from the molten resin.

Next, 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 to obtain a uniaxially oriented PET film. Subsequently, the coating liquid L was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency of 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method. Then, the edge part of the film was hold | gripped with the clip, was guide | induced to the hot air zone heated at 110 degreeC, and was extended | stretched 3.5 times in the width direction after drying. At this time, the wind speed in the tenter was 15 m / second, and the drying time was 20 seconds. The time from application to the film to the tenter entrance was 10.0 seconds. The coating amount was 0.15 g / m ² as the final solid content.

Next, while maintaining the width of the film stretched in the width direction, the first heat setting zone (200 ° C.), the second heat setting zone (205 ° C.), the third heat setting zone, and the fourth heat setting zone (210 ° C), the fifth heat setting zone (215 ° C), the sixth heat setting zone (220 ° C), and the seventh heat setting zone (170 ° C). Further, after relaxation treatment of 3% in the width direction in the seventh heat setting zone, the uncoated portions at both ends of the film were trimmed to obtain a laminated polyester film having a thickness of 125 μm. The hot air velocity in the heat fixing zone was 15 m / second, the passage time was 4.5 seconds in each zone, the nozzle interval for blowing hot air was 700 mm, and the number of nozzles per zone was four.
On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin was unclear.

(Comparative Example 2)
(1) Preparation of coating liquid M 3.0 parts by mass of 30% by mass aqueous dispersion of copolymerized polyester resin (A) used in Example 1, 20 of polyurethane resin (B) used in Example 1 18.0 parts by mass of a mass% aqueous solution, 0.3 parts by mass of a catalyst for elastron (Daiichi Kogyo Seiyaku, Cat 64), 70.7 parts by mass of water, and 4.7 parts by mass of isopropyl alcohol were mixed. . Furthermore, as a surfactant, 0.6 part by mass of a 10% by mass aqueous solution of dodecylbenzenesulfonic acid, and as a particle A, a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm). 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, A coating solution M was obtained. The pH of the coating liquid M was 4.8 because pH was not adjusted.

(2) Production of laminated polyester film After the polyethylene terephthalate resin pellets containing no particles used in Example 1 and having an intrinsic viscosity of 0.62 dl / g as a raw material polymer at 135 ° C. for 6 hours under reduced pressure (1 Torr), It was supplied to an extruder, melted and 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. to obtain a cast film. At this time, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter medium for removing foreign substances from the molten resin.

  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 peripheral speed difference to obtain a uniaxially oriented PET film. Next, the coating solution M was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency: 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method.

Subsequently, while holding the edge of the film with a clip, the film was guided to a hot air zone heated to 80 ° C., and the coated surface was dried and then stretched 4.0 times in the width direction. At this time, the wind speed in the tenter was 15 m / second, and the drying time was 20 seconds. The time from application to the tenter inlet was 10.0 seconds. The coating amount was set to 0.10 g / m ² as the final solid content. Further, the temperature in each heat setting treatment step is 200 ° C. in the first heat setting zone, 210 ° C. in the second heat setting zone, 220 ° C. in the third heat setting zone, 225 ° C. in the fourth heat setting zone, and the fifth heat. The film thickness is the same as in Comparative Example 1 except that the fixing zone is 230 ° C., the sixth heat fixing zone is 235 ° C., the seventh heat fixing zone is 240 ° C., and the relaxation treatment in the width direction is not performed. A laminated polyester film having a thickness of 125 μm was obtained.
On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin could not be observed.

(Comparative Example 3)
(1) Preparation of coating liquid N 7.5 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 1 and 20 of the polyurethane resin (B) used in Example 1 11.3 parts by mass of a mass% aqueous solution, 0.3 parts by mass of a catalyst for elastron (Daiichi Kogyo Seiyaku, Cat64), 40.5 parts by mass of water, and 39.5 parts by mass of isopropyl alcohol were mixed. Furthermore, 0.6 mass parts of a 10% by mass aqueous solution of an untreated fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, Megafuck F142D), aggregates as particles A without using particles B 0.03 parts by mass of a 3.5 mass% aqueous dispersion of silica (manufactured by Fuji Silysia Chemical Co., Ltd., Silicia 310; average particle size of 1.4 μm) was added to prepare a coating solution N. The pH of the coating liquid N was not adjusted. The pH of the coating liquid N was 4.6.

(2) Production of laminated polyester film As raw material polymer, polyethylene terephthalate resin pellets having an intrinsic viscosity of 0.62 dl / g that do not contain the particles used in Example 1 are supplied to an extruder, and formed into a sheet at about 285 ° C. It was melt extruded and rapidly cooled and solidified on a metal roll maintained at a surface temperature of 20 ° C. to obtain a cast film. At this time, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter medium for removing foreign substances from the molten resin.

  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 peripheral speed difference to obtain a uniaxially oriented PET film. Next, the coating liquid L was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency: 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method.

After the application, it was introduced into a drying furnace and dried at a temperature of 120 ° C. for 3.2 seconds. The coating amount was 0.08 g / m ² as the final solid content. The film transit time from coating to the drying furnace inlet was 3.2 seconds. Further, the wind speed in the first zone of the drying furnace is 15 m / second, and the wind speed in the second zone to the fourth zone is the same as in the first embodiment. Both zones were set to 70 m ³ / sec, and the exhaust air was naturally exhausted from before and after the drying furnace.

  Subsequently, the film was stretched in the same manner as in Example 1 except that the transverse stretching ratio was set to 4.0 times, and subjected to heat fixing and relaxation treatment in the width direction in the same manner as in Comparative Example 1, so that the film thickness was A laminated polyester film of 125 μm was obtained. On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin could not be observed.

(Comparative Example 4)
A laminated polyester having a film thickness of 125 μm in the same manner as in Example 1 except that the passage time of the film from the coating solution A applied to the film to the entrance of the drying furnace was 3.2 seconds in Example 1. A film was obtained.

(Comparative Example 5)
3.0 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 1 and 18.0% by mass of a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 1. Part, 0.3 parts by weight of elastolone catalyst (Daiichi Kogyo Seiyaku, Cat64), 37.3 parts by weight of water, and 37.8 parts by weight of isopropyl alcohol 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 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, The pH was adjusted to 6.2 with a 5% by weight aqueous sodium bicarbonate solution to obtain a coating solution O. A laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating liquid O was used as the coating liquid.

(Comparative Example 6)
12.0 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 1 and 4.5% by mass of a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 1 Part, elastron catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat 64) 0.3 parts by mass, water 42.3 parts by mass and isopropyl alcohol 37.2 parts by mass, respectively, and the interface used in Example 1 0.6 parts by mass of a 10% by mass aqueous solution of the activator, 2.3 parts by mass of a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A, and particles B As a dry process silica (Aerosil OX50, manufactured by Nippon Aerosil Co., Ltd .; average particle size 200 nm, average primary particle size 40 nm) is added 0.5 parts by mass of an aqueous dispersion of 0.5% by mass, and the pH is adjusted with a 5% by mass aqueous sodium bicarbonate solution. It was adjusted to .2, and a coating solution P. A laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating liquid P was used as the coating liquid.

(Comparative Example 7)
In Example 1, the temperature in each heat setting treatment step was 190 ° C. in the first heat setting zone, 195 ° C. in the second heat setting zone, and 200 ° C. in the third heat setting zone to the fifth heat setting zone. Obtained a laminated polyester film having a film thickness of 125 μm in the same manner as in Example 1. On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin could not be observed.

(Comparative Example 8)
In Example 1, a laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 1 except that the wind speed in the drying furnace was changed to 15 m / sec.

(Comparative Example 9)
In Example 1, a laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 1 except that the final coating amount was 0.20 g / m ² .

(Comparative Example 10)
A laminated polyester film having a film thickness of 125 μm in the same manner as in Example 1 except that the coating liquid Q in which the pH of the coating liquid was adjusted to 9.0 with a 5% by mass aqueous sodium carbonate solution was used. Got.
(Comparative Example 11)
In Example 1, a laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating liquid R prepared without blending a surfactant in the coating liquid was used.

(Example 18)
7.5 parts by weight of a 30% by weight aqueous dispersion of the copolyester resin (A) used in Example 1 and 11.3 parts by weight of a 20% by weight aqueous solution of the polyurethane resin (B) used in Example 1 Part, 0.3 parts by mass of elastolone catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat64), 40.5 parts by mass of water and 39.5 parts by mass of isopropyl alcohol were mixed. Furthermore, 0.6 part by mass of a 10% by mass aqueous solution of the surfactant used in Example 1 and particles A as aggregate silica (manufactured by Fuji Silysia Chemical, Silicia 310; average particle size of 1.4 μm) The coating solution S was obtained by adding 4.3 parts by mass of a 5% by mass aqueous dispersion, adjusting the pH to 6.2 with a 5% by mass aqueous sodium bicarbonate solution, and sequentially passing through a filter having a filtration performance of 5 μm and 1 μm. In addition, the particle | grains B were not mix | blended with the coating liquid. A laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 1 except that the coating solution S was used.

(Comparative Example 12)
In Example 1, the film thickness was the same as in Example 1 except that the coating liquid T prepared so that only the amount of the surfactant in the coating liquid was 0.60% by mass in terms of solid content was used. A laminated polyester film of 125 μm was obtained.

Example 19
In Example 1, the temperature in each heat setting treatment step is 200 ° C. in the first heat setting zone, 210 ° C. in the second heat setting zone, 215 ° C. in the third heat setting zone, 220 ° C. in the fourth heat setting zone, Example 1 except that 225 ° C. in the fifth heat setting zone, 230 ° C. in the sixth heat setting zone, 170 ° C. in the seventh heat setting zone, and 3% relaxation treatment in the width direction in the seventh heat setting zone In the same manner as above, a laminated polyester film having a film thickness of 125 μm was obtained by trimming the uncoated portions at both ends of the film.

(Comparative Example 13)
In Example 1, 7.5 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 1 and a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 1 were used. Was mixed with 0.33 parts by mass of Elastron Catalyst (Daiichi Kogyo Seiyaku, Cat64), 51.0 parts by mass of water and 26.2 parts by mass of isopropyl alcohol. 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 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, A laminated polyester film was obtained in the same manner as in Example 1 except that the pH was adjusted to 6.2 with a 5 mass% aqueous sodium bicarbonate solution and the coating solution U was used.

(Example 20)
In Example 1, as the coating apparatus, the ratio of the capacity of the coating liquid receiving tray, the capacity of the circulation tank, and the capacity of the preparation tank is the same as in Example 1 except that the coating apparatus having the following conditions was used. In the same manner, a laminated polyester film roll having a film length of 2000 m, a width of 1000 mm, and a thickness of 125 μm was obtained.
(A) Capacity of coating liquid tray / capacity of circulation tank = 1/5
(B) Capacity of circulation tank / capacity of preparation tank = 1/50
(C) Roundness and cylindricity of application roll and metering roll: 6/1000 mm
(D) No pinch roll installed between coater and drying oven

  In Examples 1 to 20 and Comparative Examples 1 to 13, the composition and characteristics of the coating solution are shown in Table 1, the coating and drying conditions are shown in Table 2, the heat setting conditions are shown in Table 3, and the film properties and characteristics are shown in Table 4. . In addition, the maximum value, minimum value, maximum value, minimum value of haze, maximum value and minimum value of adhesion to the hard coat layer in the longitudinal direction and width direction of the obtained laminated polyester film roll are shown. As shown in FIG. In addition, about the blocking resistance, it was (circle) in all the measurement points.

  In the following examples, the coating layer is selected from an epoxy crosslinking agent, a melamine crosslinking agent, and an oxazoline crosslinking agent, at least one crosslinking agent selected from an epoxy crosslinking agent, a melamine crosslinking agent, and an oxazoline crosslinking agent. An embodiment including a copolymerized polyester resin that is crosslinked with at least one crosslinking agent is shown. In addition, the following evaluation method was used for the wet heat-resistant adhesiveness used in this Example.

(8) Moist heat resistant adhesion The film samples obtained in the examples and comparative examples were stored for 1000 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90%. Next, about 5 g of a hard coating agent (Seika Beam EXF01 (B) manufactured by Dainichi Seika Co., Ltd.), which is a solvent-free photocurable acrylic resin, is placed on a glass plate having a thickness of 5 mm kept clean, and the above film sample The coating layer surface and the hard coating agent were superposed so that they were in contact with each other, and the hard coating agent was stretched by a manual load rubber roller having a width of 10 cm and a diameter of 4 cm from above the film sample. Next, from the film surface side, the hard coat layer was cured by irradiating ultraviolet rays with a high-pressure mercury lamp under the conditions of an irradiation amount of 500 mJ / cm ² , an irradiation distance of 15 cm, and a running speed of 5 m / min.

  Subsequently, the film sample which has a hard-coat layer was peeled off from the glass plate, and the hard-coat film was obtained. The surface opposite to the hard coat layer of the hard coat film was attached to a glass plate having a thickness of 5 mm to which a double-sided tape was attached. Next, 100 grid-like cuts that penetrated through the hard coat layer and the coating layer to reach the base film were made using a cutter guide having a gap interval of 2 mm.

Next, an adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) was attached to the surface having a grid-like cut. The air remaining on the interface at the time of pasting was pushed away with an eraser and removed, and after completely adhering, the adhesive tape was peeled off in the vertical direction. The number of squares peeled off by visual observation was counted, and the adhesion was obtained from the following formula. This was performed at three locations, the average value of adhesion was determined, and the heat and moisture resistance was determined according to the following criteria. In addition, what was peeled partially even with one square was made into the number which peeled.
Adhesion (%) = (1−number of peeled squares / 100) × 100
○: 71 to 100%
Δ: 51-70%
X: 0 to 50%

(Example 21)
(1) Preparation of coating solution The coating solution used in the present invention was prepared according to the following method. A reaction vessel was 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 over 3 hours. Next, 6.0 parts by mass of 5-sodium sulfoisophthalic acid was added, and esterification was performed at 240 ° C. over 1 hour, and then at 250 ° C. under reduced pressure (10 to 0.2 mmHg) over 2 hours. A polycondensation reaction was performed to obtain a copolymerized polyester resin having a number average molecular weight of 19,500 and a softening point of 60 ° C.

  Self-crosslinking polyurethane resin (B) containing 12.8 parts by mass of an aqueous dispersion of 30% by mass of the obtained copolyester resin (A) and an isocyanate group blocked with sodium sulfite (Delastron Industries, Elastron 10.3 parts by mass of a 20% by mass aqueous solution of H-3), 2.3 parts by mass of an aqueous dispersion having a solid content of 20% by mass of a methylated melamine-based crosslinking agent (Sumitomo Chemical Co., Ltd., Sumimar M-100), Elastron catalyst (Daiichi Kogyo Seiyaku, Cat 64) 0.3 parts by mass, water 39.4 parts by mass, and isopropyl alcohol 37.5 parts by mass were mixed. Furthermore, colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle) as 0.6 parts by mass of 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFuck F142D) 2.3 mass parts of a 20 mass% aqueous dispersion having a diameter of 40 nm), and 3.5 mass% aqueous dispersion of dry process silica (Nippon Aerosil, Aerosil OX50; average particle diameter 200 nm, average primary particle diameter 40 nm) as particles B 0.5 parts by mass of the liquid was added. Next, the pH of the coating solution is adjusted to 6.2 with a 5% by weight aqueous sodium bicarbonate solution, and the solution is precisely filtered with a felt-type polypropylene filter having a filtration particle size (initial filtration efficiency: 95%) of 10 μm to prepare the coating solution AA. did. In addition, the said surfactant used what was pre-processed by the following method.

  Isopropyl alcohol (IPA) was added to the above-mentioned surfactant, and heated and dissolved in a 30 ° C. hot bath to prepare a 15 mass% surfactant IPA solution. This solution was filtered with a quantitative filter paper (Advantech Toyo, No. 5C) to remove insolubles and dust in the solution. After filtering the said solution, this solution was put into the airtight glass container, and it left still for 24 hours in a 0 degreeC freezer. After 24 hours, the solution containing the precipitated solid was subjected to suction filtration using the quantitative filter paper. The solid on the filter paper was vacuum-dried to obtain a solid, diluted with water to a 10% by mass aqueous solution, and used as a pretreated surfactant.

  The surfactant obtained by the pretreatment was analyzed with a TLC-coated plastic sheet (manufactured by Merck, silica gel 60) using methanol as a developing solution. As a result of coloring the sample spot with iodine vapor, it was confirmed that a spot corresponding to polyethylene glycol was not detected.

(2) Production of laminated polyester film Polyethylene terephthalate (PET) resin pellets containing no particles and having an intrinsic viscosity of 0.62 dl / g as a raw material polymer were dried under reduced pressure (1 Torr) at 135 ° C. for 6 hours. Next, the dried PET resin pellets were supplied to an extruder, melted and 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. to obtain a cast film. At this time, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter medium for removing foreign substances in the molten resin.

  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 peripheral speed difference to obtain a uniaxially oriented PET film. Next, the coating liquid AA was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency: 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method. At this time, the application roll and the metalling roll of the coater were rolls having a surface with an ultra-hard chrome plating finish of 0.2 S or less and a roundness and cylindricity of 3/1000 mm.

Thereafter, in a drying furnace divided into four zones arranged 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 ° C., 1 The coated surface was dried for 8 seconds at a fourth zone temperature of 30 ° C. for 1.8 seconds. The coating amount was 0.08 g / m ² as the final solid content. The transit time of the film from application to the film to the entrance of the drying oven was 0.8 seconds. Further, at this time, the wind speed of the drying air in the first zone is 30 m / sec, the supply air volume of the drying air is 130 m ³ / sec, the exhaust air volume is 170 m ³ / sec, and the supply air volume from the second zone to the fourth zone Was set to 100 m ³ / sec and the exhaust air flow was set to 150 m ³ / sec so that dry air did not flow to the coater side. The tension of the film was 7000 N / raw fabric, and both ends of the film were held with pinch rolls from the coating to the drying furnace inlet.

Furthermore, in the coating at this time, a coating apparatus in which the ratio of the capacity of the coating liquid tray, the capacity of the circulation tank, and the capacity of the preparation tank has the following relationship was used.
(A) Ratio of the volume of the coating liquid tray to the volume of the circulation tank = 1/50
(B) Capacity ratio of the circulation tank to the mixing tank = 1/40

  Subsequently, while holding the edge of the film with a clip, the film was guided to a hot air zone having a temperature of 120 ° C. and a wind speed of 15 m / sec, and stretched 4.3 times in the width direction. Next, while maintaining the width stretched in the width direction, the first heat setting zone (temperature: 200 ° C.), the second heat setting zone (temperature: 225 ° C.), and the third heat setting zone (temperature: 230 ° C.) , 4th heat setting zone (temperature: 230 ° C), 5th heat setting zone (temperature: 210 ° C), 6th heat setting zone (temperature: 170 ° C), 7th heat setting zone (temperature: 120 ° C) sequentially And let it pass. Note that a relaxation treatment of 3% in the width direction was performed in the sixth heat setting zone. Next, the uncoated portions at both ends of the film are trimmed, wound up by a winding device, further divided into four equal parts in the width direction, slitted, a width of 1000 mm, a film length of 1000 m, and a film thickness of 125 μm. A laminated polyester film roll was obtained. The hot air velocity in the heat fixing zone was 15 m / second, the passage time was 4.5 seconds in each zone, the nozzle interval for blowing hot air was 350 mm, and the number of nozzles per zone was 8.

  Table 9 shows the film properties and characteristics. In addition, the maximum value, minimum value, maximum value, minimum value of haze, maximum value and minimum value of adhesion to the hard coat layer in the longitudinal direction and width direction of the obtained laminated polyester film roll are shown. 10 shows. In the obtained thermoplastic laminated polyester film roll, the fluctuation range of the PEs surface fraction in the longitudinal direction was 10%, and the fluctuation range in the width direction was 10%. The average value of the PEs surface fraction was 65%. In addition, about the blocking resistance, it was (circle) in all the measurement points.

(Example 22)
In Example 21, a 10% by mass aqueous solution of a fluorine-based cationic surfactant (manufactured by Neos Co., Ltd., Footage 310) pretreated by the same method as in Example 21 was used as the surfactant used in the coating solution. A laminated polyester film was obtained in the same manner as in Example 21 except that the coating liquid BB was changed.

(Example 23)
In the heat setting process of Example 21, the temperature of each heat setting zone is 190 ° C. in the first heat setting zone, 205 ° C. in the second heat setting zone, 220 ° C. in the third heat setting zone, and the fourth heat setting zone. A laminated polyester film was obtained in the same manner as in Example 21 except that the temperature was 220 ° C.

(Example 24)
Example 21 is the same as Example 21 except that the mass ratio of the copolyester resin, polyurethane resin, and crosslinking agent in the coating solution is changed to the following coating solution CC in which the mass ratio is changed to 55/35/10. By the method, a laminated polyester film was obtained.
(Preparation of coating solution CC)
8.3 parts by mass of the 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 21 and 7.9% by mass of the 20% by mass aqueous solution of the polyurethane resin (B) used in Example 21. Parts, 2.3 parts by mass of the crosslinking agent used in Example 21, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku, Cat 64), 40.2 parts by mass of water, and 37. 4 parts by mass were mixed. Further, 0.6 part by mass of the surfactant aqueous solution used in Example 21 and 2.3% of a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A were used. 0.5 parts by mass of a 3.5 mass% aqueous dispersion of dry process silica (manufactured by Nippon Aerosil Co., Ltd., Aerosil OX50; average particle diameter 200 nm, average primary particle diameter 40 nm) is added as mass parts and particles B, and 5 mass% sodium bicarbonate. The pH was adjusted with an aqueous solution, and a filter with a filtration performance of 5 μm and 1 μm was passed in this order to obtain a coating solution CC.

(Example 25)
Example 21 was the same as Example 21 except that the mass ratio of the copolyester resin, polyurethane resin, and crosslinking agent in the coating solution was changed to the following coating solution DD changed to 35/55/10. By the method, a laminated polyester film was obtained.
(Preparation of coating solution DD)
5.3 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 21 and 12.4% by mass of a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 21. Parts, 2.3 parts by mass of the cross-linking agent used in Example 21, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat64), 38.5 parts by mass of water, and 37. 6 parts by mass were mixed. Furthermore, 0.6% by mass of a 10% by mass aqueous solution of the surfactant used in Example 21 and a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, The pH was adjusted to 6.2 with a 5% by weight aqueous sodium bicarbonate solution, and a filter with a filtration performance of 5 μm and 1 μm was passed in this order to obtain a coating solution DD.

(Example 26)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the coating amount was 0.12 g / m ² as the final solid content.

(Example 27)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the following coating liquid EE was used, in which the amount of the surfactant in the coating liquid was changed to 0.03% by mass. .
(Preparation of coating solution EE)
In the preparation of the coating liquid of Example 21, 0.3 part by mass of a 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFac F142D), 39.4 parts by mass of water, and Isopropyl alcohol was changed to 37.5 parts by mass.

(Example 28)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the following coating liquid FF was used, in which the amount of the surfactant in the coating liquid was changed to 0.10% by mass. It was.
(Preparation of coating solution FF)
In the preparation of the coating liquid of Example 21, 1.0 part by mass of a 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFuck F142D), 39.0 parts by mass of water, and Isopropyl alcohol was changed to 37.5 parts by mass.

(Example 29)
In Example 21, the passage time of the film from the coating to the entrance of the drying furnace was 0.7 seconds, the drying time was 0.8 seconds, and the passage time of each zone in the heat setting treatment step was 3.5 seconds. A laminated polyester film was obtained in the same manner as in Example 21 except that was changed to 100 μm.

(Example 30)
In Example 21, the passage time of the film from the coating to the entrance of the drying furnace was 1.0 second, the drying time was 1.9 seconds, and the passage time of each zone in the heat setting treatment step was 6.6 seconds. A laminated polyester film was obtained in the same manner as in Example 21 except that was changed to 188 μm.

(Example 31)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21, except that the pH of the coating solution was changed to the coating solution GG adjusted to 7.9 using a 5% by mass sodium carbonate aqueous solution. .

(Example 32)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the coating layers were applied to both sides of the uniaxially oriented polyester film. In addition, the passage time of the film from the application to the film to the entrance of the drying furnace was 0.8 second on one side and 1.0 second on the opposite side.

(Example 33)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the coating amount was 0.02 g / m ² as the final solid content.

(Example 34)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the coating liquid HH that was not subjected to the surfactant pretreatment was used. On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure between the copolyester resin and the polyurethane resin can be distinguished but is somewhat unclear.

(Example 35)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the following coating liquid II was used in which the mass ratio of the dispersion medium (water / IPA) in the coating liquid was changed to 50/50. It was.
(Preparation of coating solution II)
In the preparation of the coating liquid of Example 21, 6.8 parts by mass of the 30% by mass aqueous dispersion of the polyester resin (A) used in Example 21 and 20 of the polyurethane resin (B) used in Example 21 were used. 10.1 parts by mass of a 10% by mass aqueous solution, 2.3 parts by mass of the crosslinking agent used in Example 21, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku, Cat 64), and 30.0 parts by mass of water And 46.8 parts by mass of isopropyl alcohol were mixed. Furthermore, 0.6% by mass of a 10% by mass aqueous solution of the surfactant used in Example 21 and a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, The pH was adjusted to 6.2 with a 5% by mass aqueous sodium bicarbonate solution, and a filter with a filtration performance of 5 μm and 1 μm was passed in this order to obtain a coating solution II.

(Example 36)
In Example 21, a laminated polyester film having a thickness of 125 μm was obtained in the same manner as in Example 21 except that the coating liquid JJ was used, in which the pH of the coating liquid was changed to 4.6 with acetic acid.

(Example 37)
In Example 21, a laminated polyester film was obtained in the same manner as in Example 21 except that the coating liquid KK was used in which the polyurethane resin (B) was changed to the following polyurethane resin. The polyurethane resin was obtained by the following method.
(Preparation of polyurethane resin)
93 polyester diols (OHV: 111.8 eq / ton, AV: 1.1 eq / ton) having a composition of adipic acid // 1.6-hexanediol / neopentyl glycol (molar ratio: 4 // 3/2) 22 parts by mass of xylylene diisocyanate were mixed and reacted at 95-100 ° C. for 1 hour under a nitrogen stream to obtain a urethane prepolymer (NCO / OH ratio: 1.50, free isocyanate group: theoretical value 3.29). Mass%, measured value 3.16 mass%).

  The resulting urethane prepolymer was then cooled to 60 ° C., 4.5 parts by weight of methyl ethyl ketoxime was added and reacted at 60 ° C. for 50 minutes to contain 1.3% by weight of free isocyanate and partially blocked A urethane prepolymer was obtained. Then, the said urethane prepolymer was cooled to 55 degreeC, the mixed solvent which consists of 9 mass parts of isopropyl alcohol and 140 mass parts of methanol was added, and it mixed uniformly. Next, 9.3 parts by mass of a 50% by mass aqueous sodium bisulfite solution and 5.4 parts by mass of a 30% by mass aqueous solution of N-methyltaurine were added and vigorously stirred. Water solubility began to appear after about 30 minutes, and free sodium bisulfite became almost zero after 2 hours, and the reaction was completed. Water was added thereto to obtain a 20% by mass aqueous solution that was cloudy and viscous.

(Comparative Example 14)
(1) Preparation of coating solution LL 33.7 parts by mass of dimethyl terephthalate, 20.0 parts by mass of dimethyl isophthalate, 9.1 parts by mass of 5-Nasulfodimethylisophthalate, 40.0 parts by mass of ethylene glycol 10.0 parts by mass of diethylene glycol Part, 0.049 parts by mass of calcium acetate · monohydrate, and transesterification was performed at 200 to 230 ° C. until the theoretical amount of methanol was distilled off. Next, 0.09 part by mass of orthophosphoric acid was added and polymerized at 280 ° C. under reduced pressure to obtain a copolymerized polyester resin.

Polyether containing a sulfonate group obtained by sulfonation of an ethylene oxide polyether starting from allyl alcohol with sodium metabisulfite (SO ₃ content: 8.3% by mass, polyethylene oxide content: 83% by mass), 192 parts by mass, poly 1013 parts by mass of tetramethylene adipate (number average molecular weight: 2,250) and 248 parts by mass of polypropylene oxide polyether (number average molecular weight: 550) initiated with bisphenol A were mixed and dehydrated at 100 ° C. under vacuum.

  The mixture is brought to 70 ° C., to which is added a mixture of 178 parts by weight of isophorone diisocyanate and 244 parts of hexamethylene-1,6-diisocyanate, and then the resulting mixture is heated from 80 ° C. until the isocyanate content is 5.6% by weight. The mixture was stirred at 90 ° C. The prepolymer was cooled to 60 ° C., and 56 parts by mass of biuret polyisocyanate obtained from 3 mol of hexamethylene diisocyanate and 1 mol of water, and 175 parts by mass of bischemitin obtained from isophorodiamine and acetone were added successively to form an aqueous polyurethane dispersion. Obtained.

  The copolymerized polyester resin and the polyurethane water dispersion are blended so as to be 20 parts by mass and 80 parts by mass, respectively, to prepare an aqueous dispersion having a solids concentration of 10% by mass, and the coating liquid LL did. Note that particles and a surfactant were not blended in the coating solution.

(2) Production of laminated polyester film Polyethylene terephthalate resin pellets containing no particles and having an intrinsic viscosity of 0.66 dl / g as a raw material polymer are dried at 135 ° C. under reduced pressure (1 Torr) for 6 hours and then supplied to an extruder. Then, it was melt-extruded into a sheet at about 285 ° C. and rapidly cooled and solidified on a metal roll maintained at a surface temperature of 60 ° C. to obtain a cast film. At this time, as in Example 21, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter medium for removing foreign substances from the molten resin.

Next, 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 to obtain a uniaxially oriented PET film. Next, the coating liquid LL was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency of 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method. Then, the edge part of the film was hold | gripped with the clip, was guide | induced to the hot air zone heated at 110 degreeC, and was extended | stretched 3.5 times in the width direction after drying. At this time, the wind speed in the tenter was 15 m / second, and the drying time was 20 seconds. The time from application to the film to the tenter entrance was 10.0 seconds. The coating amount was 0.15 g / m ² as the final solid content.

Next, while maintaining the width of the film stretched in the width direction, the first heat setting zone (200 ° C.), the second heat setting zone (205 ° C.), the third heat setting zone, and the fourth heat setting zone (210 ), The fifth heat setting zone (215 ° C.), the sixth heat setting zone (220 ° C.), and the seventh heat setting zone (170 ° C.) in succession. % Relaxation treatment, the uncoated portions at both ends of the film were trimmed to obtain a laminated polyester film having a thickness of 125 μm. The hot air velocity in the heat fixing zone was 15 m / second, the passage time was 4.5 seconds in each zone, the nozzle interval for blowing hot air was 700 mm, and the number of nozzles per zone was four.
On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin was unclear.

(Comparative Example 15)
(1) Preparation of coating liquid MM 3.0 parts by mass of 30% by mass aqueous dispersion of copolymerized polyester resin (A) used in Example 21 and 20 of polyurethane resin (B) used in Example 21 18.0 parts by mass of a mass% aqueous solution, 0.3 parts by mass of a catalyst for elastron (Daiichi Kogyo Seiyaku, Cat 64), 70.7 parts by mass of water, and 4.7 parts by mass of isopropyl alcohol were mixed. . Further, 0.6% by mass of a 10% by mass aqueous solution of dodecylbenzenesulfonic acid as a surfactant and 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, The coating liquid MM was used. The pH of the coating liquid MM was 4.8 because pH adjustment was not performed.

(2) Production of Laminated Polyester Film After the polyethylene terephthalate resin pellets containing no particles used in Example 21 and having an intrinsic viscosity of 0.62 dl / g as a raw material polymer under reduced pressure (1 Torr) at 135 ° C. for 6 hours, It was supplied to an extruder, melted and 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. to obtain a cast film. At this time, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter medium for removing foreign substances from the molten resin.

  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 peripheral speed difference to obtain a uniaxially oriented PET film. Next, the coating liquid MM was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency: 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method.

Subsequently, while holding the edge of the film with a clip, the film was guided to a hot air zone heated to 80 ° C., and the coated surface was dried and then stretched 4.0 times in the width direction. At this time, the wind speed in the tenter was 15 m / second, and the drying time was 20 seconds. The time from application to the tenter inlet was 10.0 seconds. The coating amount was set to 0.10 g / m ² as the final solid content. Further, the temperature in each heat setting treatment step is 200 ° C. in the first heat setting zone, 210 ° C. in the second heat setting zone, 220 ° C. in the third heat setting zone, 225 ° C. in the fourth heat setting zone, and the fifth heat. The film thickness is the same as in Comparative Example 14, except that the fixing zone is 230 ° C., the sixth heat fixing zone is 235 ° C., the seventh heat fixing zone is 240 ° C., and the relaxation treatment in the width direction is not performed. A laminated polyester film having a thickness of 125 μm was obtained.
On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin could not be observed.

(Comparative Example 16)
(1) Preparation of coating liquid NN 7.5 parts by mass of 30% by mass aqueous dispersion of copolymer polyester resin (A) used in Example 21 and 20 of polyurethane resin (B) used in Example 21 11.3 parts by mass of a mass% aqueous solution, 0.3 parts by mass of a catalyst for elastron (Daiichi Kogyo Seiyaku, Cat64), 40.5 parts by mass of water, and 39.5 parts by mass of isopropyl alcohol were mixed. Further, 0.6 mass parts of a 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink Chemical Co., Ltd., MegaFac F142D) that has not been pretreated, aggregates as particles A without using particles B 0.03 parts by mass of a 3.5% by mass aqueous dispersion of silica (manufactured by Fuji Silysia Chemical Co., Ltd., Silicia 310; average particle size of 1.4 μm) was added to prepare a coating solution NN. The pH of the coating liquid NN was not adjusted. The pH of the coating liquid NN was 4.6.

(2) Production of laminated polyester film As raw material polymer, polyethylene terephthalate resin pellets containing no particles used in Example 21 and having an intrinsic viscosity of 0.62 dl / g were supplied to an extruder and formed into a sheet at about 285 ° C. It was melt extruded and rapidly cooled and solidified on a metal roll maintained at a surface temperature of 20 ° C. to obtain a cast film. At this time, a stainless sintered filter medium having a filtration particle size (initial filtration efficiency: 95%) of 15 μm was used as a filter medium for removing foreign substances from the molten resin.

  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 peripheral speed difference to obtain a uniaxially oriented PET film. Next, the coating liquid NN was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency: 95%) of 10 μm, and applied to one side of a uniaxially oriented PET film by a reverse roll method.

After the application, it was introduced into a drying furnace and dried at a temperature of 120 ° C. for 3.2 seconds. The coating amount was 0.08 g / m ² as the final solid content. The film transit time from coating to the drying furnace inlet was 3.2 seconds. Further, the wind speed in the first zone of the drying furnace is 15 m / second, and the wind speed in the second zone to the fourth zone is the same as in Example 21 except that the supply air volume of the dry wind is changed from the first drying zone to the fourth drying speed. Both zones were set to 70 m ³ / sec, and the exhaust air was naturally exhausted from before and after the drying furnace.

  Subsequently, the film was stretched in the same manner as in Example 21 except that the transverse draw ratio was set to 4.0 times, heat-fixed in the same manner as in Comparative Example 15, and subjected to relaxation treatment in the width direction. A laminated polyester film of 125 μm was obtained. On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin could not be observed.

(Comparative Example 17)
In Example 21, a laminated polyester having a film thickness of 125 μm was prepared in the same manner as in Example 21 except that the passage time of the film from the application of the coating solution AA to the drying furnace was 3.2 seconds. A film was obtained.

(Comparative Example 18)
2.3 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 21 and 16.9% by mass of a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 21. Parts, 2.3 parts by mass of the cross-linking agent used in Example 21, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku, Cat 64), 36.9 parts by mass of water, and 37. 7 parts by mass were mixed. Furthermore, 0.6% by mass of a 10% by mass aqueous solution of the surfactant used in Example 21 and a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, The pH was adjusted to 6.2 with a 5% by mass aqueous sodium bicarbonate solution to obtain a coating solution OO. A laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 21 except that the coating liquid OO was used as the coating liquid.

(Comparative Example 19)
11.3 parts by mass of the 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 21 and 3.4% by mass of the 20% by mass aqueous solution of the polyurethane resin (B) used in Example 21. Parts, 2.3 parts by mass of the cross-linking agent used in Example 21, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat 64), 41.9 parts by mass of water and 37.2 parts of isopropyl alcohol. 0.6 parts by mass of a 10% by mass aqueous solution of the surfactant used in Example 21 and particles A as colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) 2.3 parts by mass of a 20% by mass aqueous dispersion and 0% of a 3.5% by mass aqueous dispersion of dry process silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B 5 parts by mass of, pH was adjusted to 6.2 with 5 wt% aqueous solution of sodium bicarbonate, and the coating liquid PP. A laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 21 except that the coating liquid PP was used as the coating liquid.

(Comparative Example 20)
In Example 21, the temperature in each heat setting treatment step was 190 ° C. in the first heat setting zone, 195 ° C. in the second heat setting zone, and 200 ° C. in the third heat setting zone to the fifth heat setting zone. Obtained a laminated polyester film having a film thickness of 125 μm in the same manner as in Example 21. On the surface of the coating layer of the obtained laminated polyester film, the phase separation structure of the copolyester resin and the polyurethane resin could not be observed.

(Comparative Example 21)
In Example 21, a laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 21 except that the wind speed in the drying furnace was changed to 15 m / sec.

(Comparative Example 22)
In Example 21, a laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 21 except that the coating amount was 0.20 g / m ² as the final solid content.

(Comparative Example 23)
A laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 21 except that the coating liquid QQ in which the pH of the coating liquid was adjusted to 9.0 with a 5% by mass sodium carbonate aqueous solution was used. Got.

(Comparative Example 24)
In Example 21, a laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 21 except that the coating liquid RR prepared without blending the surfactant in the coating liquid was used.

(Example 38)
7.5 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 21 and 11.3 masses of a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 21. Parts, 2.3 parts by mass of the cross-linking agent used in Example 21, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku, Cat 64), 40.5 parts by mass of water and 39.5 parts of isopropyl alcohol. Each part by mass was mixed. Furthermore, 0.6 part by mass of a 10% by mass aqueous solution of the surfactant used in Example 21 and particles A as aggregate silica (manufactured by Fuji Silysia Chemical, Silicia 310; average particle size of 1.4 μm) 4.3 parts by mass of a 5% by mass aqueous dispersion was added, the pH was adjusted to 6.2 with a 5% by mass aqueous sodium bicarbonate solution, and a filter having a filtration performance of 5 μm and 1 μm was sequentially passed to obtain a coating solution SS. In addition, the particle | grains B were not mix | blended with the coating liquid. A laminated polyester film having a film thickness of 125 μm was obtained in the same manner as in Example 21 except that the coating solution SS was used.

(Comparative Example 25)
In Example 21, the film thickness is the same as in Example 21 except that the coating liquid TT prepared so that only the amount of the surfactant in the coating liquid is 0.60% by mass in solid content is used. A laminated polyester film of 125 μm was obtained.

(Example 39)
In Example 21, the temperature in each heat setting treatment step is 200 ° C. in the first heat setting zone, 210 ° C. in the second heat setting zone, 215 ° C. in the third heat setting zone, 220 ° C. in the fourth heat setting zone, Example 21 except that the temperature was 225 ° C. in the fifth heat setting zone, 230 ° C. in the sixth heat setting zone, 170 ° C. in the seventh heat setting zone, and 3% relaxation treatment was performed in the width direction in the seventh heat setting zone. In the same manner as above, a laminated polyester film having a film thickness of 125 μm was obtained by trimming the uncoated portions at both ends of the film.

(Comparative Example 26)
In Example 21, 6.8 parts by mass of a 30% by mass aqueous dispersion of the copolyester resin (A) used in Example 21 and a 20% by mass aqueous solution of the polyurethane resin (B) used in Example 21 were used. 10.1 parts by mass, 0.3 parts by mass of an elastron catalyst (Daiichi Kogyo Seiyaku, Cat 64), 50.6 parts by mass of water and 26.2 parts by mass of isopropyl alcohol were mixed. Furthermore, 0.6% by mass of a 10% by mass aqueous solution of the surfactant used in Example 21 and a 20% by mass aqueous dispersion of colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) as particles A 0.5 parts by mass of a 3.5 mass% aqueous dispersion of 2.3 parts by mass of dry silica (Nippon Aerosil, Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) as particles B, A laminated polyester film was obtained in the same manner as in Example 21 except that the pH was adjusted to 6.2 with a 5 mass% aqueous sodium bicarbonate solution and the coating solution UU was used.

(Example 40)
In Example 21, as the coating apparatus, the ratio of the capacity of the receiving pan of the coating liquid, the capacity of the circulation tank, and the capacity of the preparation tank was different from that of Example 21 except that a coating apparatus having the following conditions was used. In the same manner, a laminated polyester film roll having a film length of 2000 m, a width of 1000 mm, and a thickness of 125 μm was obtained.
(A) Capacity of coating liquid tray / capacity of circulation tank = 1/5
(B) Capacity of circulation tank / capacity of preparation tank = 1/50
(C) Roundness and cylindricity of application roll and metering roll: 6/1000 mm
(D) No pinch roll installed between coater and drying oven

(Example 41)
In Example 21, 2.3 parts by mass of a 20% by mass aqueous dispersion of an epoxy-based crosslinking agent (manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-810) was used as the crosslinking agent used for preparing the coating liquid. A laminated polyester film was obtained in the same manner as in Example 21 except that was used.

(Example 42)
In Example 21, the coating liquid WW was used except that 2.3 parts by mass of an oxazoline-based crosslinking agent (manufactured by Nippon Shokubai Co., Ltd., Epocros series WS-700) was used as a crosslinking agent used for preparing the coating liquid. A laminated polyester film was obtained in the same manner as in Example 21.

(Example 43)
In Example 21, 7.5% by mass of a 30% by mass aqueous dispersion of the copolymerized polyester resin (A) and a 20% by mass aqueous solution of a self-crosslinking polyurethane resin (B) containing an isocyanate group blocked with sodium bisulfite. (Daiichi Kogyo Seiyaku Co., Ltd .: trade name ELASTRON (registered trademark) H-3) 11.3 parts by mass, Elastron Catalyst (Daiichi Kogyo Seiyaku Co., Ltd .: trade name Cat64) 0.3 parts by mass, water 39. 8 parts by mass and 37.4 parts by mass of isopropyl alcohol were mixed, and 0.6 parts by mass of 10% by mass aqueous solution of a fluorine-based nonionic surfactant (manufactured by Dainippon Ink and Chemicals, MegaFuck F142D), particles A As a colloidal silica (manufactured by Nissan Chemical Industries, Snowtex OL; average particle size 40 nm) 20 mass% aqueous dispersion of 2.3 parts by mass, particles B The same as Example 21 except that the coating liquid XX to which 0.5 parts by mass of a 3.5 mass% aqueous dispersion of silica (manufactured by Nippon Aerosil Co., Ltd., Aerosil OX50; average particle size 200 nm, average primary particle size 40 nm) was added was used. In this way, a laminated polyester film was obtained.

  In Examples 21 to 43 and Comparative Examples 14 to 26, the composition and properties of the coating liquid are shown in Table 6, the coating and drying conditions are shown in Table 7, the heat setting conditions are shown in Table 8, and the film properties and properties are shown in Table 9. . In addition, the maximum value, minimum value, maximum value, minimum value of haze, maximum value and minimum value of adhesion to the hard coat layer in the longitudinal direction and width direction of the obtained laminated polyester film roll are shown. 10 shows. In addition, about the blocking resistance, it was (circle) in all the measurement points.

  The laminated thermoplastic resin film of the present invention thus obtained is excellent in adhesion to functional layers such as a hard coat layer, a diffusion layer, and an antireflection layer, and also excellent in blocking resistance and transparency. Therefore, it is suitable as a base film for an optical functional film or an optical functional sheet such as a hard coat film, an antireflection (AR) film, a prism lens sheet, a transparent conductive film, an infrared absorption film, an electromagnetic wave absorption film, etc. . Moreover, it can be used also as a film for printing printed using UV ink which uses an acrylic resin as a resin component. In this case, as the thermoplastic resin film used as the substrate, an opaque film can be used in addition to the transparent film.

It is explanatory drawing of the phase image which observed the surface of the coating layer in the lamination | stacking thermoplastic resin film of this invention in the phase measurement mode of the scanning probe microscope. In the phase image of FIG. 1, it is explanatory drawing of the phase image which emphasized the outline of the interface of a light hue and a dark hue with image processing software. FIG. 3 is an explanatory diagram of a phase image in which the outline of the interface between the light hue and the dark hue in FIG. 2 is emphasized and the dark hue is filled with image processing software. FIG. 3 is an explanatory diagram illustrating a boundary line between a light hue and a dark hue in the phase image in which the outline of the interface between the light hue and the dark hue in FIG. 2 is emphasized. It is explanatory drawing which shows the height difference of the crack at the time of measuring the surface shape of the crack | wound attached to the surface of the coating layer in the wave mode using a three-dimensional non-contact surface shape measuring apparatus. In Example 1-20 and Comparative Examples 1, 4-6, and 8-13, it is explanatory drawing which shows that the PEs surface fraction of a coating layer surface and PEs mass ratio in the resin component of a coating layer do not respond | correspond. It is explanatory drawing which shows the saucer of a coating liquid, the tank for circulation of the tank for circulation, arrangement | positioning of the tank for preparation, and the circulation path | route of a coating liquid. It is explanatory drawing of the phase image which observed the surface of the coating layer in the laminated thermoplastic resin film of other embodiment of this invention in the phase measurement mode of the scanning probe microscope. FIG. 9 is an explanatory diagram of a phase image in which the outline of the interface between the light hue and the dark hue is emphasized by image processing software in the phase image of FIG. 8. FIG. 10 is an explanatory diagram of a phase image obtained by painting out the dark hue with image processing software in the phase image in which the outline of the interface between the light hue and the dark hue in FIG. 9 is emphasized. FIG. 10 is an explanatory diagram illustrating a boundary line between a light hue and a dark hue in the phase image in which the outline of the interface between the light hue and the dark hue in FIG. 9 is emphasized. It is explanatory drawing which shows the height difference of the crack at the time of measuring the surface shape of the crack different from FIG. 4 attached to the surface of the coating layer in a wave mode using a three-dimensional non-contact surface shape measuring apparatus. In Example 21-43 and Comparative Examples 14, 17-19, and 21-26, it is explanatory drawing which shows that the PEs surface fraction of a coating layer surface and PEs mass ratio in the resin component of a coating layer do not respond | correspond.

Explanation of symbols

1: Dark hue (polyester phase A mainly composed of copolymer polyester resin)
2: Bright hue (polyurethane phase B mainly composed of polyurethane resin)
3: Protrusions caused by particles 4: Lines highlighting the outline of the interface between light and dark hues 5: Profile curve of unevenness on the surface of the coating layer 6: Valley of scratches 7: Top of scratches 8: Example 1-20
9: Comparative Examples 1, 4-6, 8-13
10: Coater 11: Coating liquid tray 12: Die 13: Circulation tank 14: Preparation tank 15: Base film 16: Pinch roll 17: Examples 21-43
18: Comparative Examples 14, 17-19, 21-26

Claims (15)

A laminated thermoplastic resin film having a coating layer containing a copolymer polyester resin and a polyurethane resin on one or both sides of a thermoplastic resin film,
The coating layer has a structure obtained by microphase separation or nanophase separation into a polyester phase A mainly composed of a copolyester resin and a polyurethane phase B mainly composed of a polyurethane resin, and a scanning probe microscope. Is observed in the phase measurement mode, the area ratio (PEs surface fraction) of the polyester phase A (indicating a dark hue in the phase image) on the surface of the coating layer defined by the following formula (1) is 5 μm × 5 μm. A laminated thermoplastic resin film characterized by having a measurement area of 35% or more and less than 90%.
PEs surface fraction (%) = (Area of polyester phase A / Measurement area) × 100
... (1)   The laminated thermoplastic resin film according to claim 1, wherein the copolymerized polyester resin is crosslinked with at least one crosslinking agent selected from an epoxy crosslinking agent, a melamine crosslinking agent, and an oxazoline crosslinking agent. .   The laminated thermoplastic resin film according to claim 1, wherein particles are contained in the thermoplastic resin film, or both the thermoplastic resin film and the coating layer.   2. The laminated thermoplastic resin film according to claim 1, wherein the thermoplastic resin film contains substantially no particles and contains particles only in the coating layer.   The laminated thermoplastic resin film according to claim 3 or 4, wherein the particles are silica particles.   The laminated thermoplastic resin film according to claim 3 or 4, wherein particles in the coating layer are unevenly distributed in the polyester phase A or the polyurethane phase B.   The laminated thermoplastic resin film according to claim 1, wherein the thermoplastic resin film is a biaxially oriented polyester film or a biaxially oriented polyamide film.   The surface of the coating layer is observed in the phase measurement mode of a scanning probe microscope, and a phase image in which the outline of the interface between the light hue and the dark hue is emphasized, the boundary line between the light hue and the dark hue using the box counting method. 2. The laminated thermoplastic resin film according to claim 1, wherein a fractal dimension obtained from (interface contour) is 1.60 to 1.95 in a measurement area of 5 μm × 5 μm. The laminated thermoplastic resin film according to claim 1, wherein the hardness index of the coating layer defined below is 3.0 to 15.0 nm.
The coating layer hardness index is a needle with a sapphire with a radius of 75 μm at the tip, and the surface of the coating layer is scratched by applying a weight of 5 gf. Means the average value of each measured value when 50 height differences between adjacent convex portions and concave portions are measured.   The laminated thermoplastic resin film according to claim 3 or 4, wherein the haze of the laminated thermoplastic resin film is 1.5% or less.   The laminated thermoplastic resin film according to claim 10, wherein the laminated thermoplastic resin film is used as a base film of an optical functional film or an optical functional sheet.   The optical functional film or the optical functional sheet is any one of a hard coat film, an antireflection film, a light diffusion sheet, a prism sheet, a transparent conductive film, a near-infrared absorbing film, and an electromagnetic wave absorbing film. Item 12. The laminated thermoplastic resin film according to Item 11.   The laminated thermoplastic resin film according to claim 1, wherein a functional layer mainly composed of an acrylic resin is laminated on at least one surface of the coating layer. The thermoplastic resin film according to any one of claims 1 to 13, which has a coating layer containing a copolyester resin and a polyurethane resin on one side or both sides of the thermoplastic resin film, and has a length of 1000 m or more and a width of 50 mm. It is a laminated thermoplastic resin film roll continuously wound up in a roll shape with the above size, and the area ratio (PEs surface fraction) of the polyester phase A (showing a dark hue in the phase image) on the surface of the coating layer The difference between the maximum value and the minimum value of the PEs surface fraction on the surface of the coating layer in the longitudinal direction is 15% or less when measured at 100 m intervals in the longitudinal direction of the film. roll.
In addition, the measurement of the PEs surface fraction in the surface of the said coating layer unwinds the said laminated thermoplastic resin film roll, and the end of the steady area where the film physical property is stable about the longitudinal direction (MD) of this film. When the first end and the other end are the second end, the first measurement is performed 2 m or less inside the first end, the final measurement is performed 2 m or less inside the second end, and 1 Every 100m from the first measurement point.   The laminated thermoplastic resin film roll is unwound, the film is divided into four equal parts in the width direction, and the area ratio (PEs surface) of the polyester phase A (indicating a dark hue in the phase image) on the surface of the coating layer at each central portion. The laminated thermoplastic resin film according to claim 14, wherein a difference between the maximum value and the minimum value of the PEs surface fraction on the surface of the coating layer in the width direction is 10% or less when the fraction) is measured. roll.