TW200903095A - Polyester film for reflecting sheet - Google Patents

Abstract

The present invention provides a laminated polyester film with high quality image without nonuniformity or defects as a component of LCD with large screen. On polyester film for reflector plate, there is at least a polyester layer (A) with tiny voids, and the light transmission of laminated film is below 5.0% at wavelength of 550 nm, and the difference between maxima and minima of the light transmission of 9 intersection points, which are carried out by drawing lines at intervals of length direction 22 cm x width direction 15 cm at the region of the film with length direction 88 cm x width direction 60 cm, is below 0.5%.

Description

200903095 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to a polyester film for optics, and more particularly to a liquid crystal display for use in a large screen and preferably 40 inches or more (hereinafter , sometimes referred to as "LCD", is a laminated polyester film for reflectors that has superior optical properties and helps to improve the quality of optical products. [Prior Art] Polystyrene films, especially biaxially stretched films of polyethylene terephthalate or polyethylene naphthalate, have excellent mechanical properties, heat resistance and chemical resistance. It is widely used in magnetic tapes, magnetic thin film tapes, photographic film, packaging films, films for electronic components, electrical insulating films, metal laminated films, films for glass surfaces attached to glass displays, etc. A material such as a protective film. In recent years, polyester film has been used in a wide variety of optical films, and is used as a base film for anti-reflection or a base film for a film, a light-diffusing sheet, a reflector, a touch panel, or the like. Various uses such as a base film for explosion-proof display of a display, a film for PDP filters, and the like. In order to obtain a bright and vivid image, these optical products are used as a base film for an optical film, and in terms of the form of use thereof, foreign matter which is good in transparency and does not affect the image, scratches, etc. Defects. The polyester film is usually obtained by subjecting an amorphous sheet obtained by melt-extruding into a sheet and being subjected to rapid cooling and solidification, stretching in the longitudinal direction and the transverse direction, and applying heat treatment. If the uniformity of cooling or stretching in these steps is insufficient, the physical property inhomogeneity in the film will be caused, and as a result, when used as an optical device in 200903095, there is a problem of image deterioration and image unevenness. An important characteristic of the display is the inclusion of brightness, which is known to have a large effect on the brightness of the polyester film used as a member. Especially in the case of obtaining a high quality image, high brightness is required. If the deformation of the polyester film to be used or the difference in physical properties in the polyester film is large, it will constitute a cause of defects on the screen. Because of this, it is needless to say that planarity is required for the polyester film as the optical member, but it is important that it does not cause planarity in the planarity of the physical property when it is used as an optical member. Further, in recent years, with the large screen of the liquid crystal display, the difference between the deformation of the film and the physical properties in the large-screen display is remarkably exhibited and the performance of the display is affected. For example, in Patent Document 1, an alignment polyester film which does not cause a thickness variation of luminance unevenness is provided, which provides a method of using a specific auxiliary cooling device in the step of cooling and solidifying the molten resin sheet. . In Patent Document 2, when it is used as a liquid crystal display member, there is no unevenness or defect and high luminance can be achieved, and specific film haze and film thickness are applied to manufacture a light of a large-screen liquid crystal display of 40 inches or more. The diffusion sheet is biaxially oriented with a polyester film. Further, in Patent Document 3, it is intended to provide a base film for forming a reflecting surface having high reflection brightness and small dimensional directivity, and coating a fine particle-containing coating on a polyester film to produce a surface having fine irregularities. The shape of the liquid crystal display base film for the reflector. However, in the case of the prior art as described above, if it is used as a component of a large-screen liquid crystal display of a size of 40 inches or more, the color unevenness and the degree of inconsistency in the TfC benefit will occur in 200903095. Uniformity, and film deformation caused by obvious long-time lighting can also be observed. Therefore, it is necessary to further improve the deformation of the film or the unevenness of light transmittance and unevenness of brightness. Lightfastness to solve these problems. Japanese Laid-Open Patent Publication No. 2006-28 No. 2006-184368 (Patent Patent Document 3) Japanese Patent Application Laid-Open No. 6 1 _ 丨〇 2 6 8 7 SUMMARY OF THE INVENTION [Technical Problem to be Solved] The present invention has been made in view of the actual situation as described above, and the technical problem to be solved is to provide a use as a large screen. When the components of the liquid crystal display are used, there is no unevenness or defect, and a polyester film of a good quality image can be provided. [Technical method for solving the problem] That is, the subject matter of the present invention is as follows: (1) A polyester film for a reflecting plate having fine voids in the polyester layer (A), and the film is at a wavelength of 570 nm When the light transmittance is 5 · 0 % or less, the film has a length of 22 cm in the longitudinal direction and a line in the width direction of 15 cm in the range of 88 cm in the longitudinal direction and 60 cm in the width direction. The difference between the maximum 値 and the minimum 透光 of the transmittance at 550 nm wavelength at 9 o'clock of the intersection is 200903095 0.5% or less; (2) The vinegar film for the reflector as described in Table (1) is tied The single-layer layer of the polyester layer (A) is composed of a polyester layer (b) containing inorganic fine particles; (3) The polyester film for a reflector according to (1) or (2), which is attached to The polyester layer (A) has a void forming agent f of 10 to 80% by weight based on the total weight of the layer, and a melting point of 2 to 25% by weight is from 60 ° C to 23 ° C. a thermoplastic polyester elastomer in the range of t, which is formed by forming fine voids; (4) A reflector for use in a reflector according to item (3) The film, wherein the void-forming agent is a polymethylpentene or a cycloolefin copolymer, and the polyester film for a reflector according to any one of (1) to (4), wherein the film Draw a line with a length of 22 cm and a width of 15 cm in the length direction of 88 cm in the longitudinal direction and 60 cm in the width direction, and center on the intersection point i. When the length direction and the width direction (the length of the 1 mm direction are the length direction or the width direction) are respectively cut to a size of 100 mm x io mm, 9 pieces of the sample in the length direction or the width direction are passed through 80 ° C. When heating for 30 minutes, the heat contraction coefficient of the film is io% or less in the width direction and the length direction, and the difference between the maximum 値 and the minimum 为 is 0.3% or less; and (6) as in the first ( The polyester 200903095 film for a reflector according to any one of the items 1 to 5, which is for use in a large-screen liquid crystal display of 40 inches or more. [Effect of the Invention] When the present invention is used as a member of a large-surface liquid crystal display, it is possible to provide a high-quality image without unevenness or defects. [Embodiment] [Best Mode for Carrying Out the Invention] Hereinafter, the present invention will be further described in detail. The polyester used in the polyester layer (A) and the polyester layer (B) of the present invention is a polymer obtained by condensation polymerization of a diol and a dicarboxylic acid. Here, the "dicarboxylic acid" is represented by, for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, etc. '"diol" is, for example, Representative of diol, trimethylene glycol, tetramethylene glycol, cyclohexane dimethanol, and the like. A polyester which can be used in the polyester layer (A) and the polyester layer (B) of the present invention, specifically, for example, polyethylene terephthalate or polyethylene terephthalate can be used. And polybutylene terephthalate-1,4-cyclohexylenedimethyl ester, polyethylene-2,6-naphthalene dicarboxylate (polyethylene naphthalate), and the like, and may be the same or different. The polyester may be a homopolyester or a copolyester, and a "diol component" such as diethylene glycol, neopentyl glycol or polyalkylene glycol may be used as the copolymerization component; phthalic acid, A "dicarboxylic acid component" such as isophthalic acid, 2,6-naphthalenedicarboxylic acid or sodium 5-sulfonate isophthalate. The polyester which can be used in the present invention, since polyethylene terephthalate 200903095 and polyethylene naphthalate have superior strength, heat resistance, water resistance, chemical resistance, etc., Etc. is a very good person. Further, in the polyester used in the present invention, if necessary, a resin, an additive such as an ultraviolet absorber, a UV stabilizer, a heat stabilizer, and the like which can blend the polyester in a range which does not impair the efficacy of the present invention is required. Oxidation stabilizers, organic lubricants, organic fine particles, dips, nucleating agents, dyes, dispersants, coupling agents, and the like. Further, the polyester layer (A) and the polyester layer (B) may be composed of the same polyester component or may be composed of a heterogeneous polyester component. In the case of the single-layer polyester layer (B) of the polyester layer (A), it is preferred that the polyester layer (B) contains the inorganic fine particles described below, and the inorganic fine particles which can be contained are preferably capable of Make the film white. Further, it is preferably effective for improving gloss or reflectance, and further having superior effects against ultraviolet light resistance. "Inorganic particles" can use calcium carbonate, magnesium carbonate, zinc carbonate 'titanium dioxide, zinc oxide, antimony oxide, magnesium oxide, barium sulfate, zinc sulfide, calcium phosphate, ceria, alumina, mica, titanated mica, talc. , clay, kaolin, lithium fluoride, calcium fluoride, etc. Further, those having a bubble formation property such as calcium carbonate, barium sulfate or magnesium carbonate may be used. Further, particles in which the film is whitened by a difference in refractive index from the polyester such as titanium dioxide, zinc oxide, cerium oxide or titanated mica may be used. These inorganic fine particles may be used singly or in combination of two or more kinds thereof. Further, the inorganic fine particles may be in the form of a porous or hollow porous material, and -10 200903095 may further apply a surface treatment to improve the dispersibility to the resin without hindering the effects of the present invention. In the present invention, the raw material for the polyester layer (B) can be preferably used, for example, by uniformly mixing polyethylene terephthalate (PET) with inorganic fine particles and preliminarily combining PET with inorganic fine particles. The resulting parent mixture was obtained from a master chip. The master concentration of the inorganic fine particles (weight ratio of the precursor mixture to the inorganic fine particles) is preferably 60% by weight or less. When the concentration of the precursor mixture is more than 60% by weight, the dispersibility of the inorganic fine particles is lowered, and when it is composited, concentration unevenness is caused. Further, since the shape of the chip is in the form of a chip with respect to PET, the inorganic fine particles are mostly processed in a powder state. Therefore, when the composite is produced without using the precursor mixture, when the composite is formed, Since the step of pulverizing PET into a powder is required, the productivity is often poor. The amount of the inorganic fine particles added to the polyester layer (B) is not particularly limited, but is preferably 〇5 to 30% by weight, more preferably in terms of the total weight of the polyester layer (B). It is particularly preferred in the range of 3 to 20% by weight. If the amount added is less than the range as described above, there is a possibility that the characteristics such as whiteness and concealability (optical density) of the film are not easily improved. Conversely, if it is more than the range described above, it is possible This causes a decrease in the gloss or smoothness of the surface of the film, and when stretched, it may cause defects such as cracking of the film or dusting during post-processing. The polyester layer (A) of the present invention must have fine voids. In order to form fine voids, in the present invention, it is preferred to add inorganic fine particles or a void-forming agent composed of polyacetate-11 - 200903095 and a non-compatible resin. The "void former" is one in which inorganic fine particles or inactive fine particles such as organic fine particles, polyester and non-phase barium resin are formed, and when the polyester layer is stretched, voids are formed. The inorganic fine particles as the void-forming agent are typically calcium carbonate, barium sulfate, magnesium carbonate, titanium dioxide, zinc oxide, cerium oxide, titanium mica, etc. Further, the so-called "incompatible with polyester" The resin is a thermoplastic resin other than polyester, and the thermoplastic resin which exhibits incompatibility to the polyester is dispersed in the form of granules in the polyester, and the effect of forming bubbles in the film by stretching is achieved. For the big one. From the viewpoint of functioning as a void-forming agent and also functioning after heat treatment in the film production stage, the incompatible resin is preferably an olefin system such as polyethylene, polypropylene, polybutene or polymethylpentene. A resin, a styrene resin, a polyacrylate resin, a polycarbonate resin, a polyacrylonitrile resin, a polyphenylene sulfide resin, a fluorine resin, or the like. These may be individual polymers or copolymers, and two or more immiscible resins may also be used. Among these, polypropylene having a small critical surface tension, polymethylpentene, a polyolefin such as a cycloolefin copolymer, and polymethylpentene or a cycloolefin copolymer are particularly preferably used. Since polymethylpentene is characterized in that the difference in surface tension between the polyester and the polyester is large and the melting point is high, and the bubble formation efficiency per added amount is large, it is particularly suitable as an incompatible resin. An example of the use of polymethylpentene is to use 80% by weight of polyethylene terephthalate (PET) and 10% by weight of polymethylpentene (ρΜΡ) as PMP - 12- 200903095 The composition of 10% by weight of polyethylene glycol (peg) of the powder is mixed and dissolved. If the composition obtained by melt mixing is measured by a differential scanning calorimeter (DSC) from 25 ° C to 300 ° C, then after more than 200 ° C, it is observed at around 230 ° C. The first peak is the melting point Tm of PMP, and the second peak observed around 260 °C is the melting point of PET. Since the temperature is higher at 200 to 230 °C in the usual film heat treatment temperature, ΡP can function as a void-forming agent for the incompatible resin after heat treatment in the film production stage. Further, as described above, the void-forming agent is also suitably used as the cycloolefin copolymer resin. The preferred glass transition temperature of the cycloolefin copolymer resin is 1 20 ° C or more, 203 ° C or less, more preferably 180 ° C or more, 2 2 0 ° C or less, and still more preferably 190. Above °C, below 220 °C. Regarding the glass transition temperature, if the glass transition temperature is in the region of less than 180 ° C, it is possible to cause deformation of the cycloolefin copolymer as an incompatible resin in the heat treatment step of the film production step. The function of causing the void-forming agent to degenerate is such that the void (v 〇id ) which appears when extending is deformed or destroyed. In particular, in the case of a void which has been finely dispersed and reduced in diameter, there is a possibility that a small deformation causes a void to disappear, so that the reflectance of the white polyester film is lowered, which in turn affects the decrease in brightness. The glass transition temperature is a temperature at which the amorphous portion is transferred from the glass state to the rubber state in terms of the amorphous or semi-crystalline material, and is represented by the symbol Tg. In the present invention, the Tg is measured by using a differential scanning calorimeter (DSC)' and reading the heat-in and out-out of the heat difference caused by the difference in the two states when the temperature is changed as Tg. The method of controlling Tg is controlled by controlling the linear component and the cycloolefin moiety (the methyl-norbornene moiety can be arbitrarily changed, that is, the ratio of hydrocarbons in order to increase Tg can be achieved. The linear olefin fraction = 3:7 ratio is to further increase the cycloolefin control to be more than 180 ° C. If the Tg is in the range as described above, in addition to the effect of making the voids not easily disappear, The cycloolefin of the core of the void is high in rigidity and can be exceptionally large, and therefore is preferable. It is finely laminated to have multiple high reflectances and contributes to improvement of brightness. In the present invention, a suitable void-forming agent polyester When the total weight of the layer (A) is from 1 Torr to 80% by weight, it may cause a small number of voids and a property of f. Conversely, 'if the gap-forming agent is not well mixed with PET When the voids are agglomerated, there is a possibility that the void formation film is broken or the like, and the productivity is lowered. Due to the presence of voids as described above, the light of the film is in the boundary between the polymer and the air constituting the film. Make it possible to improve the reflectivity of the film There is no particular limitation, but it is preferable because the void is small and the reflectance is greatly increased. In addition, the 'copolymerization ratio of the olefin portion (ethylene portion) is increased to the cycloolefin portion: cycloolefin The ratio of the hydrocarbon portion may be such that when it is stretched during heat treatment, it will play a role in significantly increasing the void formation rate void, whereby the content range is relative to > if the content is less than the lower portion as the LCD member At 80% by weight, when the empty forming agents are low between each other' at the same time, it is easy to cause, and the incident on the thin surface can be reflected. The size or shape of the material is small evenly, which is more clear, due to the polyester thin-14-

200903095 Membrane is intended for use in large liquid crystal displays, preferably the gap should be uniform over a wide range. In the present invention, a method effective to uniformly divide the void-forming agent is to add a thermoplastic elastomer as a dispersing aid. The "thermoplastic polyester elastomer" is, for example, a polyalkylene glycol such as polyethylene glycol, polymethoxy group, polytetramethylene glycol or polypropylene glycol, an alkane/propylene oxide copolymer, and Sodium dodecylbenzene sulfonate, sodium salt, glyceryl monostearate, tetrabutylphosphonium sulfonate. In the case of the film of the present invention, it is particularly preferred that the polyalkylene group is polyethylene glycol or a copolymer of polybutylene terephthalate and methyl glycol. When the amount of addition is assumed to be 1 〇 〇 by weight based on the total amount of the incompatible layer, it is preferably 2% by weight or more. If it is less than 2 weight. /. When the addition is not obtained, the dispersibility is deteriorated if it is more than 25 weight. /. At the time, there is a possibility that _ the inherent characteristics of the base material are concerned. The thermoplastic polyester bomb as described above may be previously added to the film base material polymer to be adjusted as a matrix mixture (parent mixture pellet). The polyester elastomer used in the present invention preferably has a melting point of 130. (: to 2 30 °C 'more preferably in the range of 180 to 220 ° C. If the melting point of the thermoplastic polyester is lower than 160 ° C, it may cause a situation that is not easy to obtain' Therefore, it causes a decrease in brightness when causing physical spots in the film or as a reflection. Further, if it is higher than 260. (The dispersion effect is hardly observed at 3 o'clock, so it is not preferable. The thermoplastic polyester as described above) The elastomer may contain a stable external absorbent, a viscosity-increasing branching agent, a matting agent, a coloring agent, and if the ground is dispersed, the so-called alcohol, ethylene glycol, epoxy, and other alcohols, and the polytetrazene molecule 25 heavy 1 effect and lead 1 and thin film body is a thermoplastic of polymer. Within the scope of the sputum, the uniform dispersion of i is used because [agent, purple 7 can also be -15- 200903095 contains various other modifiers In the present invention, although a method of laminating the polyester layer (A) and the polyester layer (B) is preferably employed, the method at this time may be employed in a co-extrusion method in melt film formation. a method of compounding, or a method of laminating separately after separately forming films by different paths Any of the methods, but from the viewpoint of cost, etc., it is more preferable to adopt the former method. Further, since there are many voids in the polyester layer (A), it is easy to cause film breakage in film extension, and thus production is performed. The film of the present invention has a light transmittance of 5.0% or less, preferably 3.0% or less, that is, a reflectance of 95% or more. More preferably, it is more than 98%. When it is used as a liquid crystal display device in the case of 95% or less, the entire screen may be darkened so that a beautiful image cannot be displayed. Also, it must be 88 in the length direction. When the line on the film of 60 cm in the width X width direction is drawn at a distance of 22 cm in the longitudinal direction and 15 cm in the width direction, the maximum transmittance of the ninth point of the intersection at 550 nm is obtained. The difference between 値 and 値 is 〇·5 % or less. The so-called length direction means the winding direction of the film roll, and the width direction means the direction perpendicular to the winding direction of the film roll. Configured on the LCD In order to achieve a uniform sentence and high brightness, it is necessary to control the difference between the maximum 値 and the minimum 〇 to be less than 5%, and particularly preferably 0.2% or less. In the present invention, if the above is desired When the difference between the maximum 値 and the minimum 透光 of the light transmittance reaches 〇·5 % or less, the method of introducing the static mixer to be introduced before the T-die compound nozzle or the inside of the short tube may be used. - 200903095 The method of controlling the temperature to be uniform. Specifically, the method of applying the static mixer to the T-die compound nozzle before the extrusion of the T-die compound can improve the dispersion of the void former. Preferably, the static mixer of four or more stages is disposed outside the nozzle, and the void forming agent dispersed by the extruder flows in the short tube which is introduced into the j compound nozzle due to temperature difference and viscosity difference. The polymer that is closer to the wall of the tube is more prone to reaggregation, but

The shear stress is applied immediately before entering the T-die compound nozzle, thereby the force D 〇. In addition, the polyester film of the present invention is cut into lengths and centimeters, the width direction is 60 cm, and the length direction is drawn. A sample having an interval of 15 cm in the width direction and a sample having a heat for measuring the longitudinal direction and the width direction was made centering on the nine points. Here, the longitudinal direction is such that the direction in which the film roll is wound out is perpendicular to the winding direction of the film roll. The sample for length measurement is 10 cm in the longitudinal direction and 1 in the width direction. The measurement sample in the width direction is 10 cm in the longitudinal direction of 1 cm, and each of the 9 samples is passed at 80 ° C. The heat shrinkage rate of the film at the minute is preferably 1% or less in any one of the width direction and the length, preferably 5% or less, and the difference between the maximum 値 and the minimum 率 is 0.3. If it is more than %, if it is more than this range, when it is used as a large liquid crystal display, it will introduce the meltability by the heat generation of the fluorescent tube or the base of the member of a liquid crystal display. Because of before. This causes the T-die to be heat-shrinked by 2% or less in the direction of the width of the width of the joint of 88 22 cm in the width direction of the width of the gap of '22 22 cm': the heat is -17- 200903095 shrinkage, easy to form wrinkles', which may cause color unevenness or brightness unevenness on the liquid crystal display screen. The white laminated polyester film of the present invention, if its thickness is too thin, will lose its stiffness so that the workability is deteriorated, and conversely, if it is too thick, the price per unit area will increase. Sexual deterioration, at the same time, if it is considered to be used in liquid crystal displays that have been used for thinning in recent years, the total thickness of the film is generally 150 to "1 to 50 〇Vm, more preferably 170 to The range of 300//m is also advantageous in terms of ease of use in practical applications. Further, in the case of bonding with other materials, it is preferable that the upper limit of the thickness of the base polyester film for a reflector of the present invention is 500 Å or less from the viewpoint of ease of use. Next, in the polyester film for a reflecting sheet of the present invention, a manufacturing method in which the laminated layer is B/A/B will be described below, but the present invention is not limited to these examples, as long as it is only a poly The polyester film (A) may be formed of a single film or the like of the ester layer (A). In the composite film forming apparatus having the extruder (A) and the extruder (B), in order to form the polyester layer (A), the dried polyester is granulated and dried. The soluble resin and the thermoplastic polyester elastomer and the polyester pellets are previously prepared by the parent mixture granulation and the polyester pellets, and the final addition amount is as the composition of Table 1 and is supplied to be heated to 260 to 300. In the extruder (A) of °C, it is melted and introduced into the T_die compound nozzle. In the other aspect, the resin used in the polyester layer is pelletized by a pellet of the polyester pellets and inorganic fine particles, and sufficiently dried in a vacuum. Next, the dried raw materials are supplied to a -18-200903095 extruder (B) heated to 260 to 300 ° C, and melted and introduced into the T-die compound nozzle. Laminating so that the polymer of the extruder can be located on the surface layer (single side) of the polymer extruded as described above or on both surface layers (both sides) and coextruded to form a sheet. To obtain a molten laminate thin #° and introduce a static mixer into the short tube immediately before being introduced into the Τ-die compound nozzle to apply shear stress immediately before the melt extrusion. Then, the molten laminated sheet was cooled at a surface temperature to a temperature of 1 Torr to 60 ° C & _, and solidified by electrostatic cooling to form an unstretched laminated film. Then, the unextended laminate film is guided to a roll group heated to 70 to 120 ° C to extend 2 to 5 times in the longitudinal direction (longitudinal direction, that is, the progress direction of the film), and at 20 to 30 ° C. The roller group is cooled. Next, after applying a corona discharge treatment to the side of the white polyester layer (A) of the film extending in the longitudinal direction, one side of the film is held by the cooker and introduced into the tenter and heated to 90 to 150. In the atmosphere of °C, the area magnification (longitudinal stretching ratio X lateral stretching ratio) of the stretching and stretching in the direction perpendicular to the longitudinal direction (width direction) of 2 to 5 times is preferably 6 to 20 times. When the area ratio is less than 6 times, the whiteness or film strength of the film to be obtained tends to be insufficient, and conversely, when it exceeds 20 times, it tends to be broken at the time of stretching. By applying the biaxially stretched laminated film as described above, in order to complete the crystal alignment and impart planarity and dimensional stability, the application is carried out at 150 to 230 ° C for 1 to 1 in the tenter. The polyester film for the reflector of the invention of the invention of -19-200903095 can be produced by heat-treating for a second time and uniformly cooling it to a temperature, cooling it to room temperature, and then winding it up. Further, in the heat treatment step as described above, a relaxation treatment of 3 to 12% may be applied to the yellow or the longitudinal direction as needed. Further, the biaxial extension may be any one of one-by-one extension or simultaneous biaxial extension, and, after biaxially extending, may also be extended to either one of the longitudinal and lateral directions, or both directions. The stretching temperature and the magnification are preferably those corresponding to the polyester layer (A) single @gas _ r, the laminate ratio of the polyester layer (A) and the polyester layer (B), or the addition of the Λ polyester layer (Β). The amount of the inorganic fine particles added is appropriately selected. The polyester film for a reflecting plate obtained as described above has excellent uniformity in optical properties in the film, and the difference in thermal shrinkage between the longitudinal direction and the stomach g direction is small, so that thermal deformation is reduced. . Therefore, the polyester film for a reflecting plate of the invention is a film having a property suitable as a base film for a large-sized liquid crystal display. [Method for Measuring Characteristics and Method of Evaluation] The characteristics of the present invention are based on the evaluation methods and evaluation criteria as described below. (1) Melting point, glass transition temperature (Tg) Using a differential scanning calorimeter DSC type 7 (manufactured by PerkinElmer, Inc.) and placing a 5 mg sample into a test container according to JIS K7121, After melting at 300 ° C for 5 minutes, it was quenched at room temperature. The sample was heated at a rate of 1 〇 ° C / min. 'The intermediate glass transition temperature was detected, and the temperature was further increased, and the endothermic peak from the dissolution of the crystal was regarded as its melting point. -20- 200903095 (2) The number average particle diameter of the inorganic fine particles is a transmission electron microscope HU-1 2 type (manufactured by Hitachi, Ltd.), and the polyester layer (A) or poly The cross section of the ester layer (B) was enlarged to 1 〇〇, and the cross-sectional photograph observed by 〇〇〇 was obtained. That is, the particle portion of the cross-sectional photograph is drawn along the particle shape, and then the particle portion is implemented using a high-resolution image analysis processing device (Hi-Vision Image Analyzer) PIAS-IV (manufactured by PIAS Corp.). In the image processing, the average diameter when a total of 100 particles in the measurement field of view are converted into true circles is calculated as the number average particle diameter of the inorganic particles. (3) Film thickness The thickness of the polyester film for a reflecting plate was measured using a micrometer M-30 (manufactured by SONY Corp.). (4) The void-forming agent diameter in the film was subjected to a cross-sectional observation sample obtained by subjecting a film to a frozen slicer (manufactured by Microtome Co., Ltd., Japan) to sputter Pt-Pd (uranium-palladium). A scanning electron microscope ABT-32 (manufactured by Topcon Corp.) was subjected to cross-sectional photography at a magnification of 1,000 times. The cross-sectional photograph obtained by photographing randomly draws 10 空隙 void forming agent ' using a drawing paper and measures the longest side diameter and the shortest side diameter of the void forming agent according to the ratio of the cross-sectional photograph, and then The average of 1 〇〇 of the calculated enthalpy is regarded as the void forming agent diameter. Void forming agent diameter = (longest side diameter + shortest side diameter) / 2 〇 In addition, if the void forming agent is not in the shape of a spherical or duck-shaped rotating body - 21 - 200903095, the cross-sectional shape is approximated to the closest shape. Ellipse, calculated by its ellipse (long diameter + short diameter)/2. (5) Transmittance of 550 nm wavelength The light transmittance of the film thickness direction at 550 nm was measured using a fully automatic direct reading haze computer HGM-2DP (manufactured by Suga Test Instruments). rate. It is assumed that the direction parallel to the winding direction of the film roll is the length direction, the direction perpendicular to the winding direction of the film roll is the width direction, and then the film is formed on the film having a length of 88 cm X and a width direction of 60 cm. When a line having a length of 22 cm in the longitudinal direction and a distance of 15 cm in the width direction was measured, the maximum 値 and minimum 全部 of the total light transmittance at nine points of the intersection were measured, and the difference 计算 was calculated. (6) The heat shrinkage ratio is assumed to be parallel to the winding direction of the film roll, and the direction perpendicular to the winding direction of the film roll is the width direction, and is 88 cm in the longitudinal direction and 60 cm in the width direction. The range of the size is a line in which the length direction is 22 cm and the width direction is 15 cm, and the length direction and the width direction are respectively centered on the intersection of nine points (the length of the 100 mm direction is the length direction or the width direction). Cut out 100 mm x 10 mm to obtain 9 samples in the longitudinal direction or 9 samples in the width direction. Then, a load of 3 g was uniformly applied to 9 samples in the longitudinal direction or 9 samples in the width direction, and the original length was measured by an automatic heat shrinkage rate measuring device (manufactured by Techno Needs Company Ltd.). Next, it was placed in an oven at 80 ° C, and heat treatment was applied for 30 minutes, and the length after treatment was measured again by an automatic heat shrinkage measuring instrument, and the heat shrinkage rate was calculated from the following formula -22-200903095.

Heat shrinkage rate (%) = (original length - length after treatment) / original length X 100 ° (7) Due to the unevenness of brightness of the film (direct back light-type brightness), the measurement is not due to backlight (brightness) brightness unevenness, but due to the brightness unevenness of the film, it is assumed that the direction parallel to the winding direction of the film roll is the length direction, and the direction perpendicular to the winding direction of the film roll is the width. The direction is drawn, and the line having a length of 22 cm and a width of 15 cm is drawn in a range of 88 cm in the longitudinal direction and 60 cm in the width direction, and is cut at a point of intersection of nine points. 100 mm (length direction) x 100 mm (width direction) to take 9 samples, as shown in Fig. 1, remove the reflective film attached to the backlight of 181BLM07 (manufactured by NEC), and then The center portion was set in the order of each of the nine samples as described above as a film sample, and then turned on. After waiting for one hour in this state to stabilize the light source, the CCD camera DXC-3 90 (manufactured by SONY C o r p ) was used to photograph the liquid crystal face and the image was taken by EyeScale manufactured by the image analysis device I System. Thereafter, the brightness level of the image obtained by photographing is controlled to be 30,000 grades to be automatically detected' and converted into brightness. Thereafter, the difference in brightness among the nine samples is calculated as the brightness spot by the following mathematical formula: brightness spot (%) = (maximum 値 (cd/m2) - minimum 値 (cd/m2)) xlOO / max 値(cd/m2). In addition, if the brightness spot (%) is within 〇 · 8 %, it is regarded as qualified, and it is regarded as unqualified at -23-200903095. (8) The film deformation caused by the long-time lighting of the display will be cut into the center mark of the film of 40 inches and inserted into the 4 inch inch large liquid crystal display' and then the display will be continuously lit for 1 hour. The 'open display' is then taken out of the inserted film and its mark is overlapped with the center of the paper cut to a size of 40 inches as blank paper.

The difference between the vertical and horizontal dimensions of the corners of the time is ABS

Digimatic Caliper (manufactured by Mitutoyo Corporation) was measured. The evaluation criteria are as follows. Evaluation criteria: ◎ : The difference between the size of the blank paper and the blank paper is 1 mm or less, and the maximum (mm) and the minimum (mm) are 0.3 mm or less. t 〇: The difference between the size of the blank paper and the blank paper is 1 mm or less. And the maximum (mm)-minimum (mm) is 〇.3 to 0.5 mm; X: the difference between the size of the blank paper and the blank paper is 1 mm or more ' or the maximum (mm) and the minimum (mm) is 〇.5 The embodiment of the present invention will be described using the following examples and comparative examples, but the present invention is not limited thereto. [Example 1] The raw material composition of the polyester (B) layer was as follows. The cerium oxide mother--24-200903095 body mixture is pelletized (cerium dioxide content is 2% by weight, Toray Industries, Inc. (F118, manufactured by Toray Industries, Inc.) and polyethylene terephthalate) The alcohol ester dicing (F20S manufactured by Toray Industries Co., Ltd.) was mixed into cerium oxide in an amount of 0.08 wt% relative to the polyester layer (B), and vacuum was applied at 180 ° C. The drying was supplied to the extruder (B) after 3 hours, and was melted at 2 85 ° C and then introduced into a T-die compound nozzle. Raw material composition of the polyester (B) layer: PET pellets 99.92% by weight of cerium oxide (number average particle diameter: 3/zm) 0.08% by weight On the other hand, the raw material composition of the polyester (A) layer is as follows. PET pelletizing (F20S manufactured by Toray Industries, Inc.) and polymethylpentene (PMP, "TPX" DX 8 2 0 by Mitsui Chemicals, Inc.) were mixed and added. 1 〇% by weight of a thermoplastic polyester elastomer which is copolymerized with 1 〇 mol% of phthalic acid and 5 mol% of polyethylene glycol in PET (referred to as "PET/I" /PEG": "HIGHTREL" manufactured by DuPont-Toray Co., Ltd., 5 weight. /. Copolymer of polybutylene terephthalate and polytetramethylene glycol as a thermoplastic polyester elastomer (abbreviated as "PBT/PTMG": T 7 9 4 manufactured by Toray Industries, Ltd. Μ), and the total weight of the thermoplastic elastomer is 15% by weight. The composition of the polyester (Α) layer: -25- 200903095 PET pellets 65 . .00 PMP 20. .00 PET/I/PEG 10 .00 PBT/PTMG 5 .00 (total 1 〇〇 weight%) at 1 The composition was vacuum dried at 80 ° C for 3 minutes to the extruder (A), and before the extrusion nozzle, it was melted by a static mixer { ' at 2 8 5 T: with T- The layer (B) obtained by molding the composite nozzle is a sheet extruded from the two surface layers of the polyester layer (A). Then, the laminated melt sheet was electrostatically cooled and solidified on a cooling drum having a surface temperature to form a film. Thereafter, the unstretched film was guided to be heated to 85 to a group, and 3.1 times the longitudinal extension was carried out in the length direction. Next, the surface of the longitudinally extending film was held by a cooker into the tenter, and a lateral extension of 3.6 times was performed in the direction perpendicular to the I direction in an atmosphere heated at 130 °C. Thereafter, 23 (TC heat-fixed) was applied to the machine and it was uniformly cooled slowly to room temperature and then taken up to obtain a thin film having a thickness of 1 8 8 V m. The characteristics of the film were as shown in Table 1. It is shown that, as a reflective film, a film having a small unevenness can be obtained. [Example 2] In Example 1, except that the conveyance was changed to an extruder (the melting point of the composition of A, the rest was The film having the same squareness as that of Example 1 was 188/zm. Weight % Weight % Weight % Weight % After hours, it was treated with white polyester. Layer melting # into 2 5. For rolls not extended at 98 ° C The end, the length and the length are in the tentering, but the cooling [0 board is made of polyester ο. The thickness of the material is -26 - 200903095. The composition of the polyester (A) layer: 6 5.00 wt% 2 0.00 wt% 1 0.0 0% by weight 5.00% by weight

PET pelletizing PMP

PET/I/PEG PBT/PTMG (melting point: 170 ° C) (total 1% by weight) The properties of the film are as shown in Table 1, and can be obtained as a polyester film for a reflector. The unevenness is a small film. [Example 3] In Example 1, except that the composition of the raw material to be fed to the extruder (A) was changed, a film having a thickness of 1 8 8 /z m was obtained in the same manner as in Example 1. Raw material composition of polyester (A) layer: PET pellet 4 5.0 0% by weight PMP 40.00% by weight 1 0.0 0% by weight 5.00% by weight PET/I/PEG PBT/PTMG (total 100% by weight) The characteristics of the film are as As shown in Table 1, 'for a polyester film for a reflecting plate, a film having a small unevenness can be obtained. [Example 4] In Example 1, except that the composition of the raw material supplied to the extruder (A) was changed, the film having a thickness of 1 8 8 // m was obtained in the same manner as in Example 1. -27- 200903095 Raw material composition of polyester (A) layer: 2 5.0 0% by weight 5 5 · 0 0 Weight 0/〇 1 3 · 0 0 Weight. /〇 7.0 0% by weight

PET pelletized PMP PET/I/PEG PBT/PTMG (total 100% by weight) The properties of the film are as shown in Table 1, and the polyester film as a reflector can be made to have unevenness. It is a small film. [Example 5] In Example 1, except that the composition of the raw material to be fed to the extruder (B) and the composition of the raw material to be fed to the extruder (A) were changed, the same procedure as in the first embodiment was carried out. A film having a thickness of 188/zm was obtained. Material composition of the polyester (B) layer: 9 5.00 S Μ % 5.00 wt% 3 5.00 wt% 5 0.0 0 wt 0 / 〇 1 0.0 0 wt% 5.0 0 ray % PET diced cerium oxide (quantitative average particle size) 1/^m) The composition of the polyester (A) layer: PET pelletized barium sulfate (quantitative average particle size 1 μ m)

PET/I/PEG PBT/PTMG (total 100% by weight) The characteristics of the film are as shown in Table 1. For the polyester film used as the reflecting plate, the transmittance and the heat shrinkage rate are both A film with very low uniformity. -28-200903095 [Example 6] A film having a thickness of 188 m was produced in the same manner as in Example 1 except that the composition of the raw material supplied to the extruder (A) was changed. Raw material composition of polyester (A) layer: PET pellets 1 0.0 0% by weight Barium sulfate (number average particle size: I # m) 70.00% by weight PET/I/PEG 13.00% by weight PBT/PTMG 7.00% by weight (total 100% by weight) The characteristics of the film are as shown in Table 1. For the polyester film for a reflecting plate, a film having a very small unevenness in transmittance and heat shrinkage can be obtained. [Example 7] In Example 1, except that the polyester layer (A) was formed as a single film without using an extruder (B), the remaining thickness was obtained in the same manner as in Example 1. 188/zm film. The characteristics of the polyester film for a reflecting plate are as shown in Table 1, and there are no particular problems in the characteristics. [Example 8] In Example 1, except for the void-forming agent, a cycloolefin copolymer ("TOPAS" Tg manufactured by Polyplastics Co., Ltd., 160 ° C) was used, and the rest was the same as in Example 1. A film having a thickness of 1 8 8 ym was produced in the same manner. The composition of the polyester (A) layer: -29- 200903095 PET pellet 6 5.0 0 wt% ring dilute copolymer (Tg is 16 〇. (3) 20.00 wt. / 〇 PET / I / PEG 1 0.00 weight % PBT/PTMG 5.00 Weight 0/〇 (total 10% by weight) The properties of the film are as shown in Table 1 'For the polyester film used as a reflector, the transmittance can be obtained'. A film having a very small unevenness. [Example 9] In Example 8, 'the ring-forming agent was used except for the void-forming agent (Polyplastics Co., Ltd.) "TOPAS" Tg was 220. (:) Otherwise, a film having a thickness of 1 8 8 // m was obtained in the same manner as in Example 1. The composition of the polyester (A) layer: 6 5.0 0% by weight 2 0.0 0% by weight 1 0 · 0 0 Weight% 5.0 0% by weight PET pelletizing

Cyclic olefin copolymer (Tg is 220 ° C)

PET/I/PEG

PBT/PTMG (total 1% by weight) The properties of the film are as shown in Table 1. For the polyester film used as the reflector, the transmittance and the heat shrinkage ratio are very uneven. Small film. [Comparative Example 1] In Example 1, except that static mixing -30-200903095 was not used in extrusion molding, the film having a thickness of 1 8 8 Am was obtained in the same manner as in Example 1. . The characteristics of the polyester film for the reflecting plate are as shown in Table 2, and a small amount of color and brightness unevenness in the display can be observed, and the deformation of the film is large, for the film for a reflecting plate of a liquid crystal display, The features that are needed are not met. [Comparative Example 2] In Example 1, except that the composition of the raw material to be fed to the extruder (B) was changed, a film having a thickness of 1 88 // m was obtained in the same manner as in Example 1. The raw material composition of the polyester (B) layer: PET pelletized PMP (total 100% by weight) 8 0 _ 0 0 wt% 2 0.0 0 wt% The characteristics of the polyester film for the reflector are shown in Table 2, Since the "maximum one minimum" of the transmittance is large, the absolute enthalpy of the same heat shrinkage rate, the maximum enthalpy of the heat shrinkage ratio, and the minimum enthalpy difference are also large, so that the obtained film has a very large unevenness. [Comparative Example 3] In Example 1, except that the composition of the raw material to be fed to the extruder (A) was changed, the film having a thickness of 1,88 #m was obtained in the same manner as in Example 1. Raw material composition of polyester (A) layer: -31 - 200903095 P E T pelletizing

PET/I/PEG

PBT/PTMG 8 5.00 wt% 10.00 wt% 5.0 0 wt% (total 1 wt%) The characteristics of the polyester film for the reflector are as shown in Table 2, since no void former is added, in the polyester layer (B) voids were not formed, and the transmittance was very high, and the function as a polyester film for a reflector was low [Comparative Example 4] In Example 1, except that the conveyance was changed to the extruder (A). A film having a thickness of 1 8 8 μm was obtained in the same manner as in Example 1 except for the melting point of the raw material composition. Material composition of the polyester (A) layer: PET pellets 85.00% by weight PET/I/PEG 1 000 wt% 5.0 0 wt%

PBT/PTMG (melting point 150 °C (total 1% by weight) The characteristics of the polyester film for reflectors are shown in Table 2. Although a static mixer is used, the melting point of the thermoplastic elastomer is low. Further, the dispersibility was not improved, and the difference between the maximum 値 and the minimum 透射 of the transmittance was large. [Comparative Example 5] In Example 3, except that the composition of the raw material supplied to the extruder (A) was changed, The film was formed in the same manner as in Example 1-32-200903095 except that a static mixer was used, but film breakage often occurred so that the target film could not be obtained. The composition of the polyester (A) layer: 5.0 0 weight % 9 0.0 0% by weight 3.0 0 Weight./〇2.00% by weight PET granulated barium sulphate (quantitative average particle size is 1 // m)

PET/I/PEG PBT/PTMG (total 1 〇 〇% by weight) [Comparative Example 6] In Example 4, the raw material composition to be fed to the extruder (A) was changed, and a static mixer was not used. Material composition of polyester (A) layer: 8 5.0 0% by weight 5.00% by weight 7.0 0% by weight 3.0 0% by weight PET pellets Barium sulfate (quantitative average particle size is 1 //

PET/I/PEG PBT/PTMG (total 100% by weight) The characteristics of the polyester film for the reflector are as shown in Table 2, and the absolute transmittance is high and the heat shrinkage is large, so that it cannot be used as a reflector. Use a polyester film. [Comparative Example 7] In Example 1, the composition of the raw material to be fed to the extruder (A) was changed, and a static mixer was not used. The composition of the polyester (A) layer: -33- 200903095

PET pelletizing PMP PET/I/PEG PBT/PTMG 8 5.0 0% by weight 5.0 0% by weight 7.0 0% by weight 3.0 0 Weight. /〇 (total 1% by weight) The characteristics of the polyester film for a reflector are as shown in Table 2, and the absolute transmittance is high, and the function as a polyester film for a reflector is low (Comparative Example) 8] In the example (1), the raw material composition delivered to the extruder (A) was changed, and a static mixer was not used. The composition of the raw material of the polyester (A) layer: P E T pellets 5.0 0 by weight. /. PMP 90.00 weight. /〇PET/I/PEG 3.00 wt% PBT/PTMG 2.00 wt% (total 100% by weight) The characteristics of the polyester film for the reflector are as shown in Table 2, and the dispersibility is poor, and it is used as a liquid crystal display. The film for a reflector does not satisfy the required function. [Comparative Example 9] In the example (1), the raw material composition conveyed to the extruder (A) was changed, and a static mixer was not used. Raw material composition of polyester (A) layer: -34- 200903095 PET pellets 7 8.0 0 wt% PMP 1 5.0 0 wt% PET/I/PEG 5.0 0 wt% PBT/PTMG (total 1 wt%) 2.0 0 % by weight The properties of the polyester film for a reflector are as shown in Table 2, and the functions of the polyester film for a reflector are not exhibited because the voids are small and the transmittance is high. -35- 200903095 一谳1Example 9 1 | B/A/B 1 | 99.92 | 0.08 \〇ο 1 225 1 m | 220 | Cyclic olefin copolymer (Tg is 220〇C) • - You 00 00 rN ON 00 ο tri Ο inch 〇ο 〇O ο 6110 1 6107 1 0.05 | 〇〇s〇〇〇 ◎ 1 Example 8 | B/A/B | 99.92 0.08 V) Ό ο 1 225 in | 220 Cycloolefin copolymerization (Tg is 160DC) 1 • - S 〇〇00 (N <N Ο) ο so ο in ο ο 5 o ο 6031 1 6017 1 0.22 | 〇\〇〇\D Ο 〇◎ 滔 滔 < 1 • Yn Ό ο rs tN V» | 220 polymethylpentene_1 • 00 00 〇〇 (N cs 00 inch ο CO ο V) ο m ο m Ο o fN ο 5072 1 5027 1 0.88 | 〇〇\ 〇\ ο ο 〇Ό Μ | B/A/B m Os a m 〇m (N <N 卜 | 220 • O 擗〇〇〇〇(N es tN cs (Ν C) oo ο yri ο mo Ο 5055 1 5029 1 0.51 1 〇00 〇00 Ο ο ◎ 1 Example 5 | B/A/B On — vn ΓΛ ο yn <N fS ui ' — ' ftc 00 00 P (N ΓΛ (Ν ο 'Ο ο ι /~> Ο ο 2 o ο 5048 1 5042 | 0.12 | C C5 Ο ο ◎ 1 Example 4 | B/A/B 1 99.92 0.08 V-> (Ν mm <N (N 卜 | 220 polymethylpentene_1 • 'V) 00 〇〇〇〇 (S 00 m ο οο ο νΊ Ο ο (Nl oo <Ν Ο 5065 1 5021 | 0.87 | 〇CO 〇ο ΓΛ ο 〇m Retirement | B/A/B 1 99.92 m 0.08 «ο ο CN (N tn | 220 polymethylpentene ___) • • 〇〇〇00 〇〇«Ν Ο) ο Ό ο ο ο iN 〇 o (Ν Ο 5061 1 5028 | 0.65 | 〇Ό 〇V) Ο ο Ο 1 Cao Example 2 | B/A/B 1 99.92 0.08 Ό ο tN <N ir> o Polymethylpental • ' 〇&lt ;s W- 〇〇〇〇▼ inch (N Ο) Ο ο ο Tf ο rn (N 〇o (Ν Ο 5060 1 5025 | 0.69 | d卜dm o' (Ν Ο 〇1 Example 1 | B/A /B 1 99.92 m 0.08 m Ό ο «Ν u~> | 220 Polymethylpentene -1 • * CS CS ο CS ο Γ-» ο Ο rn rn <N 〇o < Ν Ο 1 5065 1 5030 I 0.69 | 〇ο inchο (Ν 〇 〇1 unit 1 halo % 1 B 4 wt% 1 wt% 1 1 wt% 1 1 1 wt% 1 1 melting point • B ϋ 1 wt% 1 1% by weight 1 When using extrusion, use static mixer 1 ε 51 B cd/m2 1 cd/m2 | £ ε Β Β mm 1 Composition 1 PET 1 inorganic micro-particle size (number average) 丨 inorganic particle amount 1 PET : I PET/I/PEG I PBT/PTMG ! Incompatible resin /"V Γ Eft Μ » em 1 inorganic particulate amount (barium sulfate Quantity) 1 _ 1 Film thickness 1 mmm Tender 1 Maximum 値 1 I® Maximum - Minimum 1 Maximum 値 1 1 Minimum 値 1 Maximum 1 Minimum 値 1 Minimum 値 1 Maximum 1 Minimum 1 Maximum 値 1 Minimum 値 Brightness 1 m Maximum値1 minimum 値1 maximum one minimum evaluation result 1 inorganic fine particles 1 thermoplastic polyester elastomer void forming agent 1 1 length 1 direction m K direction 1 due to film 1 brightness unevenness display caused by long-term lighting of the film changed to 550 1 nanometer light transmittance heat shrinkable hanging i® ig dish: <襄醒龚mm 200903095 (N撇〇s IS ±3 | B/A/B 1 | 99.92 | ΓΛ 0.08 oo »y-> ( N (N | 220 | 1 polymethylpentene 1 ' 1 〇〇 〇〇 00 〇 0 (Ν 对 · so ο Ο 'Ο ο ο ο ο ο 225 4 4 225 225 225 4 4 4 4 4 4 4 4 4 4 4 4 4 | B/A/B | 99.92 ΓΛ 0.08 ΙΛ | 225 | 220 1 polymethylpentene: ' 1 § 00 〇〇(Ν rn «η (Ν Ο) Ό d 〇\ 〇(Ν Ο ο ο ο 5 5082 1 5021 1 X σ\ ο rr ο in ο X 卜 5 镒jj | B/A/B | 99.92 Rn 0.08 k〇OO 卜 fN CM m | 220 1 polymethylpentene: , Vi 00 00 fS rn rn ττ 卜 rn Ό Ο »ri 〇Ο ο τΤ ο ο rn ο 4988 1 4913 1 m X \〇· - m ο X 1Comparative Example 6 | B/A/B 〇\ 一oo 〇· IT) fS (S m | 220 r — 1 00 00 〇〇 ON Ο (Ν — Ό ΠΊ VO ο Os Ο ο -> 〇ο ιη ο ο ^r ο 4995 1 4902 1 1.86 1 X m — ο X 1 Comparative Example 5 | B/A/B 〇\ -<ir> cn <N fN (N | 220 ( — ' * | Unable to film | | B/A/B | 99.92 0.08 m VO 〇Vi (N «Ν v> § 1 polymethylpentene 1 1 Up 〇0 00 fS rn (Ν pi οο 守 · 二Ο Ό Ο m ο ο ό ο 5001 1 4922 1 oo ir> X inch · oo ο Ό Ο X 1 Comparative Example 3 | B/A/B | 99.92 0.08 w*> CO om (N fS | 220 • 1 〇0 00 • CS Os § CS : «Λ» Ό Ο inch ο ο 254 1 248 1 2.36 | X (Ν W-) Ο Ο Ο X | B/A/B | 99.92 rn 0.08 | 1 § o fN <N o | 220 | 1 polymethyl Pentene 1 * • 〇CN 00 OC <N in ίΝ rn ΟΝ ro m ο Ο Ο Ο ιη Ο ο ο 5001 I 4902 1 oo 〇\ X —: Ο rt Ο X 1 Comparative Example 1 | B/A/ B | 99.92 rn 0.08 00 00 o tn (N «Ν | 220 | 1 polymethylpentene 1 ' 00 00 o (S \D (N σ\ 卜ο Ο ο (Ν Ο οο rf ο ο 5021 I 4952 I 1.37 | X οο ο m Ο V~i Ο <1 1 unit 1% by weight 1 1 -«mj % by weight 1% by weight 1 1% by weight 1 Melting point °c I 1% by weight I 1 melting point °c I 1 βτη Weight % I 1% by weight 1 When using the static mixer 1 ε 1_. J s? cd/m2 1 cd/m2 1 • mm I mm 1 mm 1 • Laminated to form I PET 镝 13⁄4 em 裢Amount of inorganic particles | PET I PET/I/PEG I PBT/PTMG 1 Incompatible resin ^ Inorganic particle size (quantitative average) (barium sulfate) /•"S 岫 氍挞 氍挞 藜 1 1 Incompatible resin Amount 1 1 Film thickness 1 Void forming agent diameter in film" m -K 啭 minimum 値 1 maximum - minimum 1 maximum 値 1 1 minimum 値 maximum - minimum 1 1 maximum 値 1 1 minimum 値 1 maximum - minimum _ maximum 値 1 Minimum brightness 1 睬a? Maximum 値1 Minimum 値1 Maximum-minimum evaluation result 1 Inorganic microparticles 1 Thermoplastic polyester elastomer void-forming agent 1 Length 1 丨Width Ν m Brewing a brightness unevenness display film caused by long-time lighting At 550 nm, the transmittance of heat is 1 s· _ Li — 200903095 [Simplified illustration] Figure 1 is a liquid crystal display with a reflector (direct back light-type light) Schematic diagram of a schematic cross-sectional view and a direct-type optical mode luminance measurement method. [Description of main components] 1 Reflector 2 Cold cathode tube 3 Milk white board 4 Diffuser 5 Septa 6 Polarized diaphragm 7 CCD camera 8 Image analysis device (EyeScale) -38-

Claims (1)

200903095 X. Patent application scope: 1. A polyester film for a reflecting plate, which has fine voids at least in the polyester layer (A), and the light transmittance of the film at a wavelength of 550 nm is 5 % or less. When the film has a length of 22 cm in the longitudinal direction and a line in the width direction of 15 cm in the range of 88 cm in the longitudinal direction and 60 cm in the width direction, the intersection point is at 5:00. The difference between the maximum 値 and the minimum 透光 of the light transmittance of the meter wavelength is 0.5% or less. The polyester film for a reflecting sheet according to claim 1, which comprises at least a polyester layer (B) containing inorganic fine particles in a single-layer layer of the polyester layer (A). The polyester film for a reflector according to claim 1 or 2, wherein the polyester layer (A) is contained in an amount of 10 to 80% by weight based on the total weight of the layer (A). The void-forming agent' and 2 to 25% by weight of the thermoplastic polyester elastomer having a melting point in the range of from 1 60 ° C to 230 ° C are formed to form fine voids. The polyester film for a reflecting sheet according to claim 3, wherein the void-forming agent is a polymethylpentene or a cyclic olefin copolymer. The polyester film for a reflecting sheet according to any one of claims 1 to 4, wherein the film has a length direction of 22 cm in a length direction of 88 cm and a width direction of 60 cm. a line having a width of 15 cm in the width direction and centering on the intersection of the nine points and respectively cutting the length direction and the width direction (making the direction of the 1 mm direction into the length direction or the width direction) 100 mm Χίο mm When the size of the sample is 9 minutes in the longitudinal direction or the width direction, the heat shrinkage rate of the film is 1.0% in the width direction and the length direction when heated at 80 ° C for 30 minutes - 39 - 200903095 minutes. Hereinafter, the difference between the maximum 値 and the minimum 为 is within 0.3%. 6. The polyester film for a reflector according to any one of claims 1 to 5, which is for use in a large-screen liquid crystal display of 40 inches or more. f. -40-