KR102001119B1 - Multilayered white polyester film for lcd reflector - Google Patents

Abstract

In the present invention, a polyester resin inner base layer containing micropores; An outer substrate layer laminated on one surface or both surfaces of the inner substrate layer; And an anti-blocking layer having a water contact angle of 110 DEG or more and a static friction coefficient and a dynamic friction coefficient of 0.5 or less on the external base layer are laminated.

Description

TECHNICAL FIELD [0001] The present invention relates to a laminated white polyester film for a liquid crystal display reflector. [0002] MULTILAYERED WHITE POLYESTER FILM FOR LCD REFLECTOR [

The present invention relates to a laminated white polyester film for a liquid crystal display reflector, and more particularly to a laminated anti-blocking white polyester film for a liquid crystal display reflector which has an anti- will be.

A conventional white polyester film used for a reflection plate of a liquid crystal display is generally a white polyester film in which micropores are formed in the film to maximize the reflectance as disclosed in Patent Documents 1 and 2. [ A method of imparting various functions such as an antistatic function, an inner UV function, a reflection diffusion function, and a light guide panel improvement function to the reflector through secondary processing has been pursued. Recently, a low cost method has been studied to reduce the cost by imparting functions imparted in the secondary processing to the reflector film forming process in order to impart functionality and to provide functionality. Accordingly, attempts have been made to improve the shrinkage of the light guide plate by laminating a white polyester film and introducing inorganic particles into the surface layer to form irregularities on the surface. However, as a method of introducing inorganic particles into the surface layer by lamination, there is a limitation in lowering the coefficient of surface friction, thereby causing a problem that the pattern of the light guide plate is collapsed.

Accordingly, the present inventors have completed the present invention by performing an anti-blocking coating on the surface of a conventional white polyester film for a liquid crystal display reflector during film formation, thereby producing an anti-blocking coating having low surface energy and low surface friction coefficient.

Japanese Patent Application Laid-Open No. 2009-0073054 Japanese Unexamined Patent Application Publication No. 1992-0015155

It is an object of the present invention to provide a laminated anti-blocking white polyester for a liquid crystal display reflector having an excellent anti-blocking performance and low-cost anti- Film.

The laminated white polyester film for a reflector of the present invention comprises: a polyester resin inner base layer containing micropores; An outer substrate layer laminated on one surface or both surfaces of the inner substrate layer; And an anti-blocking layer having a water contact angle of 110 DEG or more and a static friction coefficient and a dynamic friction coefficient of 0.5 or less laminated on the external base layer.

The anti-blocking layer is formed by coating an anti-blocking composition comprising 70 to 150 parts by weight of a polyurethane binder, 30 to 70 parts by weight of an epoxy-based curing agent and 5 to 20 parts by weight of highly transparent organic particles, based on 100 parts by weight of the fluorine- will be.

The fluorine-based acrylic polymer compound is preferably an acrylate polymer compound containing a derivative derived from polytetrafluoroethylene, fluorinate ethylene-propylene, perfluoroalkoxy, perfluoroalkylene or the like as a substituent.

The highly transparent organic particles are formed of high-purity polystyrene or high-purity acrylic resin, and preferably have a particle diameter of 0.1 to 0.5 mu m.

The fine pores of the inner base layer may be formed by stretching a blend comprising a polyester resin and an amorphous cyclic olefin copolymer resin that is non-compatible with the polyester resin and white inorganic particles.

According to the present invention, the laminated anti-blocking white polyester film for a liquid crystal display reflector has an anti-blocking function on at least one side of the inner substrate layer, and is not broken by friction with the light guide plate.

1 is a schematic cross-sectional view showing the structure of a laminated anti-blocking white polyester film for a liquid crystal display reflector according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings. 1, in the laminated anti-blocking white polyester film 10 for a liquid crystal display reflector of the present invention, an outer base layer 12 is formed on both sides of a polyester resin inner base layer 11 including micropores It is. The outer substrate layer 12 is formed on both surfaces of the inner substrate layer 11 but in the other embodiment of the present invention the outer substrate layer 12 is formed only on one surface of the inner substrate layer 11 .

The inner base layer 11 is preferably formed with micropores (not shown). The fine pores are formed by mixing a polyester resin serving as a base material of the inner base layer 11 with a blend containing an amorphous cyclic olefin copolymer resin that is non-compatible with the polyester resin and white inorganic particles, And then stretched. The micropores serve to reflect light due to the refractive index difference between the base resin and the air layer in the micropores.

The size of the fine pores is preferably 2 to 15 mu m in average length of the major axis. When the major axis length is less than 2 탆, the reflection efficiency is lowered, and when it is more than 15 탆, the micropores are connected and the film is easily torn. The major axis and the minor axis ratio (subspecific ratio) of the micropores are functions determined by the elongation ratio.

On the other hand, the content of the fine pores in the inner base layer 11 is preferably distributed in a proportion occupying 40 to 80% of the cross-sectional area. When the fine pores also contain less than 40% of micropores in the inner base layer 11, the reflection efficiency is lowered, and when it is more than 80%, the fine pores are easily wrinkled or torn.

The outer base layer 12 is located on one side or both sides of the inner base layer 11 therebetween, and is formed of a polyester film containing a small amount of inorganic particles, which is characteristic of a support.

At least one surface of the outer base layer 12 has an anti-blocking function and has a coating layer having a thickness of 0.5 to 1.5 탆.

The laminated anti-blocking white polyester film 10 for a liquid crystal display reflector of the present invention is characterized in that an outer base layer 12 as a support is provided on at least one side of the polyester resin inner base layer 11 containing micropores, The anti-blocking layer 13 is formed on at least one surface of the external base layer 12, so that even when there is friction with the light guiding plate LGP, the anti-blocking layer 13 is not broken.

A laminated anti-blocking white polyester film for a liquid crystal display reflector according to the present invention is a laminated anti-blocking white polyester film for a liquid crystal display reflector, which comprises a resin composition containing a polyester resin as a main component and an amorphous cyclic olefin copolymer resin which is an incompatible resin for the polyester resin, A raw material composition 1 containing particles; A polyester resin and a raw material composition 2 containing a small amount of inorganic particles is melted as each layer and co-extruded at the same time is cooled in a casting drum, And then a small amount of a surfactant is added to 70 to 150 parts by weight of a polyurethane binder, 30 to 70 parts by weight of an epoxy curing agent and 5 to 20 parts by weight of a highly transparent organic particle, The composition is prepared by diluting the composition in water, drying it after coating, biaxially stretching it in the direction perpendicular to the moving direction of the film, and then curing the coating layer by heat treatment.

The polyester resin used as a base resin constituting each layer in the present invention is composed of a dicarboxylic acid component and a diol component. In the present invention, as the dicarboxylic acid component, terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, adipic acid or sebacic acid may be used, As the component, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol or 1,6-hexanediol can be used.

Preferably, a polyethylene terephthalate resin having high stability and low cost is used as a basic constitution. On the other hand, when polyethylene terephthalate is used as the polyester resin, it is preferable to use copolymerized polyester containing 15 mol% or less of copolymerization component per total dicarboxylic acid content or 15 mol% The following copolymerized polyester may be used. In order to obtain a good film-forming property, isophthalic acid or 2,6-naphthalene dicarboxylic acid may be used as the dicarboxylic acid component, and in order to stabilize the dispersion state of the incompatible resin, 1,4-cyclohexanedimethanol Can be used.

The raw material composition 1 is applied to the inner base layer 11. The resin composition contained in the raw material composition 1 contains a polyester resin in an amount of 65 to 95% by weight, more preferably 70 to 90% by weight. At this time, if the content of the polyester resin is out of the above range, it can not be formed into a film containing a large number of cavities.

In the present invention, the resin composition in the raw material composition 1 contains an amorphous cyclic olefin copolymer as an incompatibility resin for the polyester resin, and bicyclo [2,2,1] hept-2 - ene, 6-methylbicyclo [2,2,1] hept-2-ene, 5,6-dimethylbicyclo [2,2,1] hept- , 1] hept-2-ene, 6-ethylbicyclo [2,2,1] hepto-2-ene, 6-n-butylbicyclo [ -Butylbicyclo [2,2,1] hept-2-ene, 7-methylbicyclo [2,2,1] hepto-2-ene, tricyclo [4,3,0,12.5] Methyl-tricyclo [4,3,0,12.5] -3-decene, 5-methyl-tricyclo [4,3,0,12.5] -3-decene, tricyclo [ 12.5] -3-decene, 10-methyl-tricyclo [4,4,0,12.5] -decene and the like, or amorphous cyclic olefin resins such as the crystalline of ethylene, propylene, butene, The polyolefin resin It may be selected from a polymerized.

The above-mentioned incompatible resin for the polyester resin may be used as a polymer composed of a single component, a copolymer composed of two or more components, or a mixture of two or more kinds thereof. Particularly, a resin having a large difference in critical surface tension from the polyester resin and hardly being deformed by heat treatment after stretching is preferable, and a copolymer of ethylene and bicycloalkene is most preferable.

In the present invention, the amorphous cyclic olefin copolymer is contained in an amount of 5 to 35 parts by weight, preferably 10 to 30 parts by weight, based on the total weight of the raw material composition 1. When the content of the amorphous cyclic olefin copolymer is less than 5 parts by weight, whitening effect is weak and high reflectivity can not be realized. On the other hand, if the content exceeds 35 parts by weight, the mechanical properties such as the strength of the film itself deteriorate and aggregation of the amorphous cyclic olefin copolymer tends to occur.

The amorphous cyclic olefin copolymer used in the present invention is obtained by separating from the resin composition in the raw material composition 1 and measuring the transition temperature according to the measuring method of JIS K7121-1987 by using a differential scanning calorimeter and measuring no crystallization and melting peaks Is set as an amorphous condition.

In a preferred embodiment of the present invention, a copolymer resin between ethylene and norbornene is used as an amorphous cyclic olefin copolymer which is an incompatible resin for a polyester resin. The copolymer resin between ethylene and norbornene can be prepared by the liquid phase polymerization method exemplified in the well-known Japanese Patent Application Laid-Open No. 61-271308.

The amorphous cyclic olefin copolymer used in the present invention preferably has a glass transition temperature of 120 ° C to 220 ° C. If the glass transition temperature is less than 120 캜, the cyclic olefin copolymer is plastic-deformed upon stretching of the film to inhibit the formation of cavities. On the other hand, when the glass transition temperature is higher than 220 캜, when the polyester resin and the amorphous cyclic olefin copolymer are melt-kneaded using an extruder or the like and discharged into a sheet, the dispersion of the amorphous cyclic olefin copolymer becomes insufficient The shape and number of the cavities can not be attained to a desired level. More preferably, the glass transition temperature of the amorphous cyclic olefin copolymer is from 150 to 215 캜, and most preferably from 170 to 205 캜. The glass transition temperature can be adjusted by changing the copolymerization ratio of the cyclic olefin and the non-cyclic olefin in the amorphous cyclic olefin copolymer. The glass transition temperature is elevated at a rate of 20 ° C / min using a differential scanning calorimeter Is determined by the midpoint of JIS K7121-1987.

In the present invention, the amorphous cyclic olefin copolymer is selected to have a particle diameter of 0.5 to 5.0 μm. When the particle size of the cyclic olefin copolymer is less than 0.5 占 퐉, it is difficult to form a void at the time of stretching, and when it exceeds 5.0 占 퐉, the film tends to be torn at the time of stretching, which deteriorates film formability.

In addition, the raw material composition 1 of the present invention contains 1 to 40 parts by weight, preferably 2 to 30 parts by weight, more preferably 3 to 20 parts by weight, based on 100 parts by weight of the sum of the polyester and the amorphous cyclic olefin resin, By weight. When the content of the white inorganic particles is less than 1 part by weight, scattered light due to the inorganic particles is insufficient and sufficient light reflectivity can not be obtained. When the content is more than 40 parts by weight, the film formation stability remarkably decreases.

The inorganic particles preferably have an average particle diameter of 0.1 to 3.0 탆, more preferably 0.2 to 2.0 탆, and most preferably 0.3 to 1.0 탆, in order to obtain good dispersibility and film forming stability. Respectively. Here, the average particle diameter refers to the number average particle diameter, and the particle diameter is arbitrarily determined for each particle before being added to the resin (film) at a magnification of 10,000 at a scanning electron microscope to determine the average particle diameter size . At this time, when the particle is not spherical, it is approximated to the ellipse having the closest shape and is determined by the ellipse (long diameter + short diameter) / 2. Particles with a particle diameter of less than 0.01 탆 and a particle diameter of 10 탆 or more are excluded.

The inorganic particles usable in the present invention include barium sulfate particles or titanium dioxide particles, which may be used alone or in combination within the above-mentioned content range.

A method of blending barium sulfate particles or titanium dioxide particles into a resin composition can be carried out by using the following known methods (a) to (d):

(A) a method in which particles are added before the transesterification reaction or the esterification reaction in the synthesis of the polyester, or the method in which the particles are added before the polycondensation reaction (in the polyester synthesis, the titanium dioxide particles are dispersed in glycols Slurry, and then added to the reaction system)

(B) a method of adding particles to a polyester and melting and kneading,

(C) a method of producing a master pellet in which a large amount of particles are added in the method (a) or (b), kneading the master pellets and a polyester containing no additives to contain a predetermined amount of additives, and

(D) The master pellet of the above (c) is used as it is.

According to the embodiment of the present invention, barium sulfate particles or titanium dioxide particles are mixed into the resin composition by the method of (c) or (d), taking into consideration the dispersibility of the particles.

Further, the raw material composition 1 of the present invention may contain various additives such as a fluorescent brightener, a crosslinking agent, a heat stabilizer, an oxidation stabilizer, an ultraviolet absorber, an organic lubricant, an inorganic fine particle , A filler, an anti-light agent, an antistatic agent, a nucleating agent, a dye, a dispersing agent, a coupling agent and the like.

The raw material composition 2 is applied to at least one side or both sides of the inner base layer 11 as a center. In the present invention, the inorganic particles used in the raw material composition 2 are used in an amount of 0.1 to 30 parts by weight, preferably 0.2 to 25 parts by weight, based on 100 parts by weight of the polyester resin. As the inorganic particles, silica, calcium carbonate, titanium dioxide, barium sulfate and the like can be used, and these particles are used in combination of at least one kind. It is preferable that the diameter is within 1 to 5 탆 in diameter. If it is smaller than 1 탆, it is difficult to form projections on the surface layer portion and is vulnerable to the running property and windability of the film. If it exceeds 5 탆, There is a problem that abrasion may occur. Therefore, it is preferable to use them in combination of one or more of these particles in the range of 1 to 5 mu m.

The thickness of the film composed of the raw material composition 1 and the raw material composition 2 can be 50 to 350 μm, and the internal base layer made of the raw material composition 1 preferably accounts for 90% or more of the total film thickness.

The anti-blocking layer 13 is located on one side of the external base layer 12 and contains 70 to 150 parts by weight of a polyurethane binder, 30 to 70 parts by weight of an epoxy curing agent, And 5 to 20 parts by weight of an anti-blocking coating composition prepared by diluting an anti-blocking composition prepared by adding a small amount of a surfactant to water. The fluorine-based acrylic polymer compound usable herein refers to an acrylate polymer compound containing a derivative derived from polytetrafluoroethylene or fluorinate ethylene propylene, perfluoroalkoxy, perfluoroalkylene or the like as a substituent. These are fluorine-based compounds of Shiba Chemical or DuPont which are well dispersed in water. Products available in product status include, for example, children. ZONYL available from DuPont de Nemours and Company; OLEOPHOBOL from Ciba Specialty Chemicals; ASAHI GARD COMPANY, LIMITED ASAHI GARD; Daikin America, Inc .; (UNIDYNE) from Daikin America, Inc.; SCOTCHGARD from 3M Company; And Nanotex's Nanotex. ≪ / RTI >

The polyurethane binder is used for the purpose of improving the adhesion between the anti-blocking layer and the substrate layer. Known urethane binders can be used, and commercially available products include DPI Holdings or DIC. When the amount of the polyurethane binder is less than 70 parts by weight based on 100 parts by weight of the fluorine-based acrylic polymer based on the solid content, the highly transparent organic particles easily fall off. When the amount is more than 150 parts by weight, surface energy is increased, .

As the curing agent, a known epoxy curing agent can be used. Commercially available ones include, for example, the product CR-5L of Dainippon Ink and Chemicals, Incorporated.

When the amount of the curing agent is less than 30 parts by weight based on 100 parts by weight of the fluorine-based compound, the coating tends to be soft and easily scratched. When the amount of the curing agent is more than 70 parts by weight, uniform curing is difficult.

As the highly transparent organic particles, highly transparent organic particles such as high-purity polystyrene resin particles, high-crosslinked acrylic resin particles and the like can be used with a particle diameter of 0.1 to 0.5 탆. When the amount of the highly transparent organic particles is less than 5 parts by weight based on 100 parts by weight of the fluorine-containing acrylic polymer compound, a static friction coefficient is 0.5 or more and a dynamic friction coefficient is 0.5 or more. It is easy to fall out.

A surfactant, for example, a fluorochemical surfactant may be added to the combination of these in a small amount of 1 part by weight or less based on 100 parts by weight of the fluorochemical acrylic polymer for the purpose of dispersion.

The laminated anti-blocking white polyester film for a reflector of the present invention can be produced by melting the raw material compositions 1 and 2 as described above, followed by coextrusion and stretching.

Specifically, the raw material composition 2 is laid on both sides of the raw material composition 1, and the molten material on the formed sheet is rapidly quenched into a casting drum while being discharged through a sheet-like extrusion die.

Subsequently, the cooled sheet is uniaxially stretched in the moving direction of the film, and the unstretched sheet can be heated by heating means such as roll heating and infrared heating (heater) before stretching. The stretching step is preferably carried out using the main speed difference of two or more rolls, and the stretching temperature is set to a temperature equal to or higher than the glass transition temperature (Tg) of the polyester resin, and the stretching magnification is 2.5 to 4.0 times. After the raw material of the anti-blocking layer is well dispersed in water, the coating process is performed and then dried at a temperature of 70 to 90 DEG C, and then continuously dried in a direction perpendicular to the film moving direction (hereinafter also referred to as " width direction & Axis stretching. The coating of the anti-blocking layer may be applied by known coating methods such as roll coating, Meier bar coating and the like known in the art. The thickness of the anti-blocking layer is preferably 0.1 to 1.5 mu m. Since the particle size is 0.1 占 퐉, the thickness of the anti-blocking layer should be at least 0.1 占 퐉 or more. If it is more than 1.5 탆, there is a problem that a large amount of particles are stacked and particles easily fall off.

 At this time, the transverse stretching is performed by raising the temperature from a temperature higher than the glass transition point (Tg) of the polyester resin. The temperature increase in the widthwise stretching process may be continuous or stepwise (sequential), but usually the temperature is sequentially increased. For example, the width direction stretching zone of the tenter is divided into a plurality of zones along the film running direction, and the temperature is raised by flowing a heating medium at a predetermined temperature for each zone. At this time, the draw ratio in the width direction is 2.5 to 4.5 times.

Thereafter, heat treatment such as heat fixing or thermal relaxation is sequentially performed while running the stretched film. The heat treatment is performed in a tenter at 120 to 240 ° C for 1 to 30 seconds to complete the crystal orientation of the obtained biaxially stretched film and to cure the anti-blocking layer to complete the film and provide planarity and dimensional stability do.

Further, during the heat treatment step, the film may be subjected to a relaxation treatment of 3 to 12% in the width direction or the longitudinal direction, if necessary.

Subsequently, after stretching, the heat-set film is uniformly cooled to room temperature, and then the film is taken up to obtain an inner substrate layer 11 and a substrate film laminated with an outer substrate layer 12 laminated on both surfaces or one surface thereof .

Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples are intended to be illustrative of the present invention, but the present invention is not limited thereto.

≪ Example 1 >

A resin composition comprising 10 parts by weight of a copolymer resin of ethylene and norbornene as an amorphous cyclic olefin copolymer having a glass transition temperature of 200 캜 and a particle diameter of 0.8 탆, as a non-resisting resin for a polyethylene terephthalate resin, relative to 100 parts by weight of a polyethylene terephthalate resin 20 parts by weight of titanium dioxide having an average particle diameter of 0.4 占 퐉 was added to prepare a raw material 1,

A raw material 2 containing 0.5 part by weight of silica inorganic particles having an average particle diameter of 4 占 퐉 was prepared per 100 parts by weight of a polyethylene terephthalate resin.

90 parts by weight of a polyurethane binder dispersion (C181-004 by DPI), 40 parts by weight of an epoxy curing agent (manufactured by Daiko Ink CR-5L) and 0.3 part by weight of a polyurethane binder dispersion An anti-blocking coating solution was prepared by diluting 10 parts by weight of dispersed high-purity polystyrene particles (JSR SX872626-03) with water containing 0.1 wt% of a fluorinated surfactant.

The raw material 1 and the raw material 2 were prepared so that the raw material 1 was an intermediate layer and the raw material 2 was discharged on both sides on the basis of the raw material 1 and fed to one sheet type extrusion die to form a sheet. At this time, the ratio of the raw material 2: raw material 1: raw material 2 was 1: 10: 1.

The molded sheet was allowed to settle on a casting drum having a surface temperature of 20 DEG C and cooled and solidified by an air chamber to obtain an unstretched film. The unstretched film was heated to 3.7 times in the film advancing direction and cooled.

Next, the anti-blocking coating liquid was sprayed evenly onto the sheet, and the coating film was maintained at a constant thickness of Meyer immediately. The coated film was dried at about 110 ° C. for 30 seconds, and then the both ends of the uniaxially stretched film were clipped And stretched at a magnification of 3.7 in a direction perpendicular to the film advancing direction (width direction) in a heated atmosphere.

Thereafter, the thin film made of the raw material 3 was cured by performing heat fixation at 220 占 폚 in a tenter, and then cooled to room temperature to obtain a biaxially stretched laminated white polyester having an anti-blocking layer thickness of 0.5 占 퐉 A film was obtained.

≪ Example 2 >

In preparing the anti-blocking coating liquid in Example 1, the same steps as in Example 1 were carried out except that the amount of the highly transparent organic particles was increased to 20 parts by weight with respect to 100 parts by weight of the fluorine-based acrylic polymer, Whereby a biaxially stretched laminated white polyester film was obtained.

≪ Example 3 >

In Example 1, the anti-blocking coating solution was diluted 2-fold in water and carried out in the same manner to obtain a biaxially stretched laminated white polyester film having an anti-blocking layer with a thickness of 0.25 탆.

≪ Comparative Example 1 &

The same procedure as in Example 1 was repeated except that the amount of the curing agent was reduced to 20 parts by weight of the curing agent relative to 100 parts by weight of the fluorine-containing compound to prepare a biaxially stretched laminated white polyester film having an antiblocking layer of the same thickness ≪ / RTI >

≪ Comparative Example 2 &

The biaxially stretched laminated white polyester film having an antiblocking layer of the same thickness was obtained in the same manner as in Example 1, except that the amount of highly transparent organic particles was reduced to 3 parts by weight with respect to 100 parts by weight of the fluorine-based compound in the anti- .

≪ Comparative Example 3 &

A biaxially stretched laminated white polyester film having an anti-blocking layer of the same thickness was obtained in the same manner as in Example 1 except that the fluorine-based compound was not used in the anti-blocking coating solution.

≪ Comparative Example 4 &

The same procedure as in Example 1 was repeated except that the amount of highly transparent organic particles was increased to 25 parts by weight with respect to 100 parts by weight of the fluorine-containing compound, to thereby obtain a biaxially stretched laminated white polyester film having an antiblocking layer of the same thickness ≪ / RTI >

≪ Comparative Example 5 &

In Example 1, the same steps as above were carried out except that the size of the organic particles was reduced by using 10 parts by weight of highly transparent organic particles and 0.08 mu m monodispersed melamine resin particles (Beckamine PM-80) in the anti- To obtain a biaxially stretched laminated white polyester film having an anti-blocking layer.

The biaxially stretched polyester films produced according to Examples 1 to 3 and Comparative Examples 1 to 5 were evaluated for performance as follows, and the results are shown in Table 1.

<Experimental Example 1> Reflectance measurement

The biaxially stretched polyester film produced according to Examples 1 to 3 and Comparative Examples 1 to 5 was subjected to an integral sphere in a spectrophotometer (UV-3600) manufactured by Shimazu Corporation of Japan and a standard white plate (BaSO ₄ ) was taken as 100%, the reflectance was measured over an area of 440 to 700 nm. From the obtained data, the reflectance was read at intervals of 5 nm, and an average value was calculated to calculate an average reflectance.

Experimental Example 2 Measurement of water contact angle

In the above Examples 1 to 3 and Comparative Examples 1 to 5, ion-exchange water was distilled using a contact angle meter (Kyowa Interface Science Co., Ltd., Model Dropmaster 300) And the average value was taken after 5 measurements at different positions. The water contact angle was classified as OK above 110˚ and NG below 110˚.

<Experiment 3> Measurement of Friction Coefficient

In the above Experimental Examples 1 to 3 and Comparative Examples 1 to 5, the TR type friction coefficient measuring apparatus of Toyoseiki was used. The measurement results were obtained by measuring the unicoder U-228 of Nippon Denshi Kagaku Co., . The measurement method was measured based on the ASTM D 1894 standard. The measurement film was placed on the upper plate and the lower plate, and the coefficient of static friction and the coefficient of dynamic friction were measured by rubbing with a weight of 200 ± 5 g and a measuring speed of 152 ± 30 mm, respectively.

&Lt; Experimental Example 4 >

In the above Examples 1 to 3 and Comparative Examples 1 to 5, two samples were sampled at a size of 100 mm x 100 mm. The anti-blocking layers were laminated facing each other. Then, the lower film was pulled while pressing with a weight of 50 g, and then the anti- A total of 10 points were observed at a magnification of 2 times, and when there was no dropout of the particles, it was OK.

&Lt; Experimental Example 5 >

In Examples 1 to 3 and Comparative Examples 1 to 5, the number of wounds was observed using a steel wool of # 0000 when a load of 10 gf / cm &lt; 2 &gt; The hardness was classified into the following five levels according to the level of the wound, and the level 3 or higher was judged as the usable level.

Level 5: No scratches.

Level 4: 1 to 5 wounds.

Level 3: 5 ~ 10 injuries.

Level 2: More than 10 wounds

Level 1: The entire surface is scarred.

division reflectivity(%) Water contact angle Constant friction coefficient Coefficient of friction Particle decolorization Steel wool evaluation Example 1 102.5 115 0.43 0.45 OK Level 4 Example 2 102.3 113 0.39 0.35 OK Level 5 Example 3 102.4 110 0.48 0.49 OK Level 3 Comparative Example 1 102.3 113 0.43 0.44 NG Level 2 Comparative Example 2 102.5 110 0.71 0.90 OK Level 1 Comparative Example 3 102.3 67 0.62 0.59 OK Level 1 Comparative Example 4 102.3 115 0.35 0.32 NG Level 4 Comparative Example 5 102.2 114 1.02 1.14 OK Level 1

As can be seen from the above Table 1, the polyester films produced in Examples 1 to 3 all had a static friction coefficient and a dynamic friction coefficient of 0.5 or less and no particle dropout. In Comparative Example 1, even though the friction coefficient is low due to a small amount of the curing agent, scratches are easily generated due to a weak surface, and particle dropout occurs. When the amount of highly transparent particles is small as in Comparative Example 2, And the friction coefficient was high and the scratches were easily generated even when the amount of the fluorine compound was small as in Comparative Example 3. [ In addition, as shown in Comparative Example 4, when an excess amount of the high-input particles is added, the particles are relatively easily removed, and thus the particles are easily removed. Also, as in Comparative Example 5, if the particle size is too small, the friction coefficient is not lowered, and a scratch is easily generated on the front surface.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

As described above, the laminated white anti-blocking polyester film produced according to the present invention does not break due to friction with a light guide plate (LGP) by introducing an anti-blocking layer having a low surface energy and a low coefficient of friction, BLU), it can be used as a reflective film for LED backlight unit.

10. Laminated white anti-blocking polyester film.
11. Internal substrate layer
12. Outer substrate layer
13. Anti-blocking layer

Claims (5)

A polyester resin inner base layer containing fine pores; An outer substrate layer laminated on one surface or both surfaces of the inner substrate layer; And an anti-blocking layer having a water contact angle of 110 DEG or more and a static friction coefficient and a dynamic friction coefficient of 0.5 or less on the external base layer,
The anti-blocking layer is formed by coating an anti-blocking composition comprising highly transparent organic particles,
Wherein the highly transparent organic particles are formed of high-purity polystyrene or high-purity acrylic resin and have a particle diameter of 0.1 to 0.5 占 퐉. The anti-blocking layer according to claim 1, wherein the anti-blocking layer comprises 70 to 150 parts by weight of a polyurethane binder, 30 to 70 parts by weight of an epoxy curing agent, and 5 to 20 parts by weight of highly transparent organic particles, Wherein the polyester film is formed by coating the composition. The fluorine-based acrylic polymer compound according to claim 2, wherein the fluorine-based acrylic polymer compound is an acrylate polymer compound containing a derivative derived from polytetrafluoroethylene, fluorinate ethylene-propylene, perfluoroalkoxy, perfluoroalkylene or the like as a substituent Layer laminate type polyester film for a liquid crystal display reflector. delete The method according to claim 1, wherein the micropores contained in the inner base layer are formed by stretching a blend comprising a polyester resin as a base material and an amorphous cyclic olefin copolymer resin that is non-compatible with the polyester resin and white inorganic particles Wherein the liquid crystal display reflector is a laminated white polyester film for a liquid crystal display reflector.

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