JP5031883B2 - Laminated polyester film - Google Patents

Description

  The present invention relates to a laminated film, and more particularly to a laminated film capable of improving the visibility when various surface functional layers are laminated on the coating layer surface of the film, for example, a liquid crystal display (hereinafter referred to as LCD). , A plasma display panel (hereinafter abbreviated as PDP), organic electroluminescence (hereinafter abbreviated as organic EL), and the like.

  Conventionally, laminated films in which coating layers having various functions such as adhesiveness and antistatic properties are provided on the film are used for manufacturing display members such as liquid crystal polarizing plates, retardation plates, PDPs, and organic ELs. It is used for optical applications. These optical films are required to have excellent transparency and visibility.

  In recent years, with the advancement of the IT (Information Technology) field, various defects due to deterioration in visibility have become more obvious due to external light reflection and improved quality of laminated films used in the production of LCD, PDP, organic EL display members, etc. Tend to.

  Base film constituting release film for protecting adhesive layer used for LCD display production, base film for cathode ray tube (hereinafter abbreviated as CRT) or antireflection film for LCD display, base film for touch panel The substrate film for a prism lens sheet, the substrate film for a CRT glass scattering prevention film, the substrate film for electronic paper, etc., which are constituent members of a liquid crystal display device, require particularly excellent transparency.

  When a laminated film is used as the various base films described above, high-quality and high-accuracy video display due to recent digitization of images is easily affected by external light reflection, and visibility may deteriorate. In general, in order to prevent external light reflection, an antireflection layer is processed on the surface or the surface is subjected to glare treatment. Since glare treatment cannot handle high-quality images, an antireflection treatment layer is often processed on the surface. The antireflection layer uses the light interference phenomenon by alternately laminating a high refractive index layer and a low refractive index layer to prevent reflection of external light. Usually, sputtering, wet processing with sol-gel, etc. are performed several times to create a laminate. In order to achieve high antireflection performance, it is necessary to control the film thickness of the processed film on the nanometer order. In order to dislike the surface defects due to foreign matter, it is necessary to carry out the process in a clean process, resulting in high costs and an expensive film.

  On the other hand, laminated films generally have poor adhesion to other materials such as anti-reflection layers and hard coats mainly composed of acrylic resins, so polyester resins, acrylic resins, urethane resins, etc. are laminated on the film. (For example, Patent Documents 1 and 2). However, since the refractive index is fixed to around 1.50 in the conventional lamination with the resin as described above, the antireflection performance may be limited when designing the antireflection film.

JP-A-10-119215 JP 2000-246855 A

  This invention is made | formed in view of the said situation, Comprising: The solution subject is excellent in transparency, and when a various surface functional layer is laminated | stacked, it provides the laminated | multilayer film which has the outstanding antireflection ability. It is in.

  As a result of intensive studies in view of the above circumstances, the present inventors have found that the use of a laminated film having a specific configuration can easily solve the above-described problems, and have completed the present invention.

That is, the gist of the present invention, a coating agent containing alkenyl substituted nadimide at least coated on one side of the base polyester film, have a coated layer provided by drying, specular reflectivity of the coating layer surface The laminated polyester film is characterized by being 5.0% or more at an arbitrary wavelength of 350 to 800 nm .

  According to the laminated film of the present invention, it is possible to provide a laminated film excellent in antireflection performance when various surface functional layers are laminated on the coating layer surface of the film, and its industrial value is high.

  As a film base in the present invention, a laminated polyester film excellent in mechanical properties and heat resistance is used in order to prepare for a subsequent step when the surface functional layer is provided on the upper layer of the laminated film. The polyester film may have a single layer structure or a laminated structure, and may have a multilayer of four layers or more as long as it does not exceed the gist of the present invention other than a two-layer or three-layer structure. It is not particularly limited.

  The polyester used for the film in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyester includes polyethylene terephthalate and the like. On the other hand, the dicarboxylic acid component of the copolyester includes isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxybenzoic acid, etc.), etc. 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexane dimethanol, neopentyl glycol, is mentioned. In any case, the polyester referred to in the present invention refers to a polyester that is usually 60 mol% or more, preferably 80 mol% or more of polyethylene terephthalate or the like which is an ethylene terephthalate unit.

  It is preferable to mix | blend particle | grains with the film in this invention for the main purpose of providing lubricity. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, it is possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed during the manufacturing process of the film raw material.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color. These series of particles may be used in combination of two or more as required.

  Moreover, the average particle diameter of the particle | grains to be used is 0.01-3 micrometers normally, Preferably it is the range of 0.01-1 micrometer. When the average particle diameter is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient. On the other hand, when the average particle diameter exceeds 3 μm, the surface roughness of the film becomes too rough and Problems may occur when various surface functional layers are applied in the process.

  Furthermore, the particle content in the film is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is.

  The method for adding particles to the film is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage of producing the polymer constituting each layer.

  In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments and the like can be added to the film in the present invention as necessary.

  Although the thickness of the film in this invention will not be specifically limited if it is a range which can be formed into a film as a film, Usually, it is 5-250 micrometers, Preferably it is the range of 5-200 micrometers.

  Next, although the manufacture example of the film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all.

  That is, a method of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, the film is stretched in the direction perpendicular to the first stretching direction. In that case, the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. is there. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  In the present invention, the simultaneous biaxial stretching method can be adopted for the production of the film constituting the laminated film. The simultaneous biaxial stretching method is a method in which the unstretched sheet is usually stretched and oriented in the machine direction and the width direction at 70 to 120 ° C., preferably 80 to 110 ° C., and stretch ratio. As an area magnification, it is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear driving method can be employed.

  Furthermore, what is called an in-line coating which processes the film surface during the extending process of the above-mentioned film can be given. When the coating layer is provided on the film by in-line coating, coating can be performed simultaneously with stretching, and the thickness of the coating layer can be changed by the stretching ratio, so that a film suitable as a film can be produced.

  Next, formation of the coating layer in the present invention will be described. The coating layer constituting the laminated film in the present invention may be provided on the film by the above-mentioned in-line coating, or may be applied off-system on the film once manufactured, so-called off-line coating may be employed, and both are used in combination. May be. Note that in-line coating is preferably used in that the production of the laminated film can be handled at low cost.

  Although in-line coating is not limited to the following, for example, in longitudinal biaxial stretching, particularly longitudinal stretching is completed, and coating treatment can be performed before lateral stretching. When a coating layer is provided on a film by a coating stretching method, coating can be performed simultaneously with film formation, and the coating layer can be processed at a high temperature, so that a film suitable as a film can be produced.

  In the present invention, it is an essential requirement to have a coating layer by coating a coating agent containing alkenyl-substituted nadiimide on at least one side of a substrate film and drying it.

  Examples of the alkenyl-substituted nadiimide include JP-A-59-80662, JP-A-60-178862, JP-A-61-18761, JP-A-61-197556, and JP-A-63-170358. JP-A-7-53516, JP-A-7-70288, JP-A-7-179816, JP-A-8-120025, JP-A-8-277265, JP-A-11-286623, etc. The known alkenyl-substituted nadiimides described can be used, and generally alkenyl-substituted nadiimides represented by the following general formula (1) are used.

In the above formula, R ¹ and R ² may be the same or different and each represents a hydrogen atom or a methyl group, and n represents an integer of 1 or 2. R ³ is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or a monovalent aromatic having 6 to 12 carbon atoms when n is 1. A group or a benzyl group, or a group-[(C _q H _2q O) _t (C _r H _2r O) _u C _v H _{2v + 1} ] (where q, r and v are each an integer of 2 to 6) T represents an integer of 0 or 1, u represents an integer of 1 to 30) or a group —C ₆ H ₄ —T—C ₆ H ₅ {where T is —CH ₂ —, —C ( Represents CH ₃ ) ₂ —, —CO—, —O—, —S—, —SO ₂ —.

R ³ is an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a group — [(C _x H _2x O) _y (C _z H _2z O) _w C when n is 2. _b H _2b ]-(wherein x, z and b each represent an integer of 2 to 6, y represents an integer of 0 or 1, and w represents an integer of 1 to 30), 6 to 6 carbon atoms 12 divalent aromatic groups, group —R—C ₆ H ₄ — (R ′) _m — (where m represents an integer of 0 or 1, and R and R ′ may be the same or different. , Represents a C 1-4 alkylene group or a C 5-8 cycloalkylene group) or a group —C ₆ H ₄ —A—C ₆ H ₄ — {where A is —CH ₂ —, —C ( _{CH 3) 2 -, - CO} -, - O -, - OC 6 H 4 C (CH 3) 2 C 6 H 4 O -, - S -, - SO 2 - shows a. }.

In the R ³ group, 1 to 3 hydrogen atoms may be substituted with a hydroxyl group, a carboxyl group, an amino group, a mercapto group, a carbamoyl group, or an isocyano group.

In the general formula (1), examples of the asymmetric alkylene-phenylene group contained in the group —R—C ₆ H ₄ — (R ′) _m — represented by R ³ in the case of n = 2 include, for example, the formula ( What is represented by 2) is mentioned.

An example of the alkenyl-substituted nadiimide represented by the general formula (1) is as follows.

(Where n is 1) N-methyl-allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N-allyl-allylbicyclo [2.2.1] hept-5 -Ene-2,3-dicarboximide, N-cyclohexyl-allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N-phenyl-allylbicyclo [2.2.1]. ] Hept-5-ene-2,3-dicarboximide, N-benzyl-allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide.

(Where n is 2) N, N′-ethylene-bis (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide), N, N′-hexamethylene-bis ( Allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide), N, N'-dodecamethylene-bis (allylbicyclo [2.2.1] hept-5-ene-2 , 3-dicarboximide), N, N′-cyclohexylene-bis (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide), 1,2-bis [3 ′ -(Allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximido) propoxy] ethane, bis [2 '-[3' '-(allylbicyclo [2.2.1] hept -5-ene-2,3-dicarboximide) propoxy Ethyl] ether, 1,4-bis [3 ′-(allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximido) propoxy] butane, N, N′-p-phenylene- Bis (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide), N, N′-m-phenylene-bis (allylbicyclo [2.2.1] hept-5- Ene-2,3-dicarboximide), N, N′-p-xylylene-bis (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide), N, N ′ -M-xylylene-bis (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide), N- [4- (allylbicyclo [2.2.1] hept-5- Ene-2,3-dicarboximidoethyl) phenyl Allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, 2,2-bis [4 ′-[4 ″-(allylbicyclo [2.2.1] hept- 5-ene-2,3-dicarboximido) phenoxy] phenyl] propane, bis [4- (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximido) phenyl] methane, Bis [4- (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboximido) phenyl] ether, bis [4- (allylbicyclo [2.2.1] hept-5 Ene-2,3-dicarboximido) phenyl] sulfone.

  The alkenyl-substituted nadiimide used in the present invention is not limited to these. In addition, these alkenyl-substituted nadiimides may be used alone, in combination of a plurality of types, or may be used as an oligomer.

In order to cure alkenyl-substituted nadiimide more efficiently, for example, an organic peroxide, an inorganic peroxide, an onium salt, a cation catalyst, and an organic group-containing metal compound can be used in combination as a curing catalyst.

In the laminated film of the present invention, a binder polymer is added to improve antireflection performance and transparency when various surface functional layers are laminated on the coated surface, and to improve adhesion to various surface functional layers. It can also be used in combination.

  The “binder polymer” used in the present invention is a number average molecular weight (Mn) measured by gel permeation chromatography (GPC) according to a polymer compound safety evaluation flow scheme (sponsored by the Chemical Substance Council in November 1985). ) Is a polymer compound having a molecular weight of 1000 or more and having a film-forming property.

  Specific examples of the binder polymer include polyester resin, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkylene imine, methyl cellulose, hydroxy cellulose, and starch. And the like.

  By including a binder polymer having an aromatic ring skeleton in the above-described binder polymer in the coating layer, the antireflection ability when various surface functional layers are laminated on the coating surface is further improved. preferable.

  Furthermore, a crosslinking agent may be used in combination in the coating layer as long as the gist of the present invention is not impaired, and specific examples include methylolated or alkylolated urea, melamine, guanamine, acrylamide, and polyamide systems. Examples thereof include compounds, oxazoline compounds, epoxy compounds, aziridine compounds, block polyisocyanates, and silane coupling agents. These crosslinking components may be previously bonded to the binder polymer.

  Further, for the purpose of improving the adhesion and slipperiness of the coating layer, inert particles may be contained, and specific examples include silica, alumina, kaolin, calcium carbonate, titanium oxide, organic particles, and the like.

  Furthermore, as long as it does not impair the gist of the present invention, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, etc. May be contained.

  Regarding the content of the compound derived from the alkenyl-substituted nadiimide in the coating layer constituting the laminated film in the present invention, it is preferable that the following formula (3) is satisfied.

10 ≦ W ≦ 100 (3)
(In the above formula, W represents the weight% of the compound derived from the alkenyl-substituted nadiimide in the coating layer constituting the laminated film)

  It is preferable to produce a laminated film by applying the above-described series of compounds as a solution or a dispersion onto a film with a coating solution adjusted to a solid content concentration of about 0.1 to 50% by weight.

  Furthermore, in the case of in-line coating, the above-mentioned series of compounds is used as an aqueous solution or water dispersion, and a laminated film is applied in such a manner that a coating solution adjusted to a solid content concentration of about 0.1 to 50% by weight is applied onto the film. Is preferably produced. Moreover, in the range which does not impair the main point of this invention, a small amount of organic solvents may be contained in the coating liquid for the purpose of improving dispersibility in water, improving film-forming properties, and the like. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

A stacking films of the present invention, the coating amount of the coating layer provided on the film (after drying) is generally 0.005~1g / ^{m 2,} preferably in the range from 0.005 to 0.5 / ^{m 2.} When the coating amount is less than 0.005 g / m ² , the uniformity of the coating thickness may be insufficient. On the other hand, when the coating is applied in excess of 1 g / m ² , problems such as a decrease in slipperiness may occur.

  In the present invention, as a method for providing the coating layer, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating or the like can be used. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979.

  In the present invention, the drying and curing conditions for forming the coating layer on the film are not particularly limited. For example, when the coating layer is provided by off-line coating, it is usually 80 to 200 ° C. for 3 to 40 seconds. The heat treatment is preferably performed at 100 to 180 ° C. for 3 to 40 seconds as a guide.

  On the other hand, when the coating layer is provided by in-line coating, heat treatment is usually performed at 70 to 280 ° C. for 3 to 200 seconds as a guide.

  Further, irrespective of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as required. You may give surface treatment, such as a corona treatment and a plasma treatment, to the film which comprises the laminated | multilayer film in this invention previously.

  The specular reflectance of the polyester film on which the coating layer is laminated is 5.0% or more, preferably 5.5% or more at an arbitrary wavelength of 350 to 800 nm, and the specular reflectance of the polyester film on which the coating layer is not laminated. The following is preferable. Further, when the wavelength is plotted on the horizontal axis and the specular reflectance is plotted on the vertical axis, it is represented by a curve having a minimum value between 400 and 700 nm, and the difference between the maximum value and the minimum value between 400 and 700 nm is 2.0. % Or less is preferable. When the specular reflectance is below 5.0%, or when there is no minimum value between 400 and 700 nm, or when the difference between the maximum and minimum values between 400 and 700 nm exceeds 2.0% When the various surface functional layers are laminated on the coating layer of the film, the antireflection ability deteriorates, so that the interference unevenness becomes strong, and the visibility may be lowered.

  In addition, in the present invention, the total light transmittance of the laminated film is 80% or more, such as optical uses such as those used in the production of display members such as LCDs, PDPs, and organic ELs. Is preferable, and more preferably 85% or more. When the total light transmittance is less than 80%, the transparency becomes insufficient. For example, when used in an inspection process involving optical evaluation, there may be a problem that foreign matters are easily overlooked.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Measurement of average particle diameter (d ₅₀ : μm) Integration (weight basis) 50% in equivalent spherical distribution measured using centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) Was the average particle size.

(3) Measurement of specular reflectance from the surface of one coating layer in the film A black tape (vinyl tape VT-50 manufactured by Nichiban Co., Ltd.) was pasted on the measurement back surface of the laminated film, and a spectrophotometer (UV manufactured by Shimadzu Corporation) -3100PC type), the specular reflectance of the coating layer surface was measured at an incident angle of 8 °, a wavelength range of 350 to 800 nm, a sampling pitch of 1.0 nm, a slit width of 20 nm, and a medium scanning speed.

(4) Measuring method of specular reflectivity The specular reflectivity in the wavelength range of 350 to 800 nm was measured, and the minimum value and the measurement wavelength corresponding to the minimum value were determined. Further, the difference between the maximum value and the minimum value of the specular reflectance in the wavelength range of 400 to 700 nm was also measured and calculated.

(5) Interference unevenness evaluation method UV curing consisting of 45: 40: 10: 5 by weight of pentaerythritol acrylate: N-methylolacrylamide: N-vinylpyrrolidone: 1-hydroxycyclohexyl phenyl ketone on the coating layer side of the polyester film. The system composition was uniformly applied so that the film thickness after curing was 5 μm, and then cured by irradiating with ultraviolet rays with a high-pressure mercury lamp having an intensity of 80 W / cm for 30 seconds to form a hard coat layer. On the hard coat layer, a low refractive index layer (SiO ₂ , 30 nm), a high refractive index layer (TiO ₂ , 30 nm), a low refractive index layer (SiO ₂ , 30 nm), a high refractive index layer (TiO ₂ , 100 nm). ) And a low refractive index layer (SiO ₂ , 100 nm) were formed in this order by sputtering. The obtained film was visually observed under a three-wavelength light region type fluorescent lamp, and interference unevenness was observed.

The polyester used in the examples and comparative examples was prepared as follows.
<Manufacture of polyester>
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, the temperature is raised by heating, methanol is distilled off, transesterification is performed, and 4 hours are required from the start of the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, 0.04 part of ethyl acid phosphate, 0.03 part of antimony trioxide and 0.01 part of silica particles having an average particle diameter of 1.5 μm were added, and then the temperature reached 280 ° C. and the pressure reached 15 mmHg in 100 minutes. After that, the pressure was gradually reduced after that to finally reach 0.3 mmHg. After 4 hours, the system was returned to normal pressure to obtain polyethylene terephthalate having an intrinsic viscosity of 0.61.

Examples of compounds constituting the coating layer are as follows.
(Example compounds)
Alkenyl-substituted nadiimide (A): A compound represented by the following formula (3) was used.

Binder polymer (B1): Water dispersion monomer composition of polyester resin copolymerized with the following composition: (acid component) terephthalic acid / 5-sodiumsulfoisophthalic acid // (diol component) ethylene glycol / diethylene glycol = 92/8 // 77/23 (mol%)
Binder polymer (B2): Polyvinyl alcohol having a saponification degree of 88 mol% and a polymerization degree of 350 Crosslinking agent (C): Hexamethoxymethylmelamine Particle (D): Silica sol having an average particle diameter of 65 nm

Example 1:
The produced polyethylene terephthalate was dried at 180 ° C. for 4 hours in an inert gas atmosphere, melted at 290 ° C. by a melt extruder, extruded from a die, and cooled by setting the surface temperature to 40 ° C. using an electrostatic application adhesion method. It cooled and solidified on the roll and the unstretched sheet was obtained. Next, the obtained unstretched sheet was first longitudinally stretched 3.6 times at 95 ° C., and the following coating agent was applied by a bar coating method, then guided to a tenter, and successively biaxially 4.3 times transversely. Stretching was performed. Thereafter, the film was heat-set at 230 ° C. for 3 seconds to obtain a 50 μm thick film provided with a coating layer having a coating amount (after drying) of 0.1 g / m ² and having the composition shown below.
<< Coating layer composition >>
Alkenyl-substituted nadiimide (A): 97% by weight
Particle (D): 3% by weight
The concentration of the coating solution was 10% by weight.

  As shown in Table 2 below, the finished laminated film had high specular reflectance, no interference unevenness when the surface functional layer was laminated on the coated surface, and the visibility was good.

Example 2 to Example 8:
In Example 1, a film was obtained in the same manner as in Example 1 except that the coating composition was changed to the coating composition shown in Table 1 below. As shown in Table 2, the finished laminated film had a high specular reflectance, had no interference unevenness when the surface functional layer was laminated on the coated surface, and had good visibility.

Comparative Example 1:
In Example 1, except having changed a coating agent composition into the coating agent composition shown in Table 1, it manufactured like Example 1 and obtained the laminated | multilayer film. The completed laminated film is as shown in Table 2. The minimum value of the specular reflectance is 4.9%, and when the surface functional layer is laminated on the coated surface, unevenness of interference occurs and visibility deteriorates. I have.

Comparative Example 2 to Comparative Example 3:
In Example 1, a film was obtained in the same manner as in Example 1 except that the coating composition was changed to the coating composition shown in Table 1. As shown in Table 2, the finished laminated film had a low specular reflectance, and when the surface functional layer was laminated on the coated surface, interference unevenness occurred and visibility was deteriorated.

  The laminated film of the present invention can be suitably used for, for example, LCDs, PDPs, organic ELs, and other optical uses for producing display members, as well as uses that place importance on visibility.

Claims (1)

A coating agent containing alkenyl substituted nadimide at least coated on one side of the base polyester film, have a coated layer provided by drying, specular reflectivity of the coating layer surface, any wavelength 350~800nm A laminated polyester film having a wavelength of 5.0% or more .