WO2018025663A1 - White polyester film for molding and white resin molded body - Google Patents

White polyester film for molding and white resin molded body Download PDF

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Publication number
WO2018025663A1
WO2018025663A1 PCT/JP2017/026458 JP2017026458W WO2018025663A1 WO 2018025663 A1 WO2018025663 A1 WO 2018025663A1 JP 2017026458 W JP2017026458 W JP 2017026458W WO 2018025663 A1 WO2018025663 A1 WO 2018025663A1
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Prior art keywords
film
molding
white
resin
polyester film
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PCT/JP2017/026458
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French (fr)
Japanese (ja)
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内田裕仁
仲村博門
前川茂俊
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東レ株式会社
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Priority to JP2017549538A priority Critical patent/JPWO2018025663A1/en
Publication of WO2018025663A1 publication Critical patent/WO2018025663A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F21V7/22—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements

Definitions

  • the present invention relates to a white polyester film for molding and a white resin molded article that are suitably used as a direct type backlight unit.
  • the backlight has a structure of a surface light source called an edge light type or a direct type in order to meet the demand for not only irradiating light but also irradiating the entire screen uniformly.
  • edge-light type backlights that irradiate light from the side are applied.
  • a backlight of a direct type that is, a type of irradiating light from the back surface to the screen is applied.
  • Lamp reflectors and reflectors used in such surface light sources for liquid crystal screens are required to have high light reflection performance.
  • a film to which is added, a film containing fine bubbles inside, or a film obtained by bonding these films to a metal plate, a plastic plate or the like has been used.
  • a film containing fine bubbles inside is widely used because it has a certain effect in improving luminance and uniforming screen luminance (Patent Documents 1 and 2). Large TVs with direct backlights are equipped with a function called “local dimming”.
  • a light reflecting plate Patent Document 3 on which a concave light reflecting surface is formed can be used.
  • a foam sheet has a problem that voids are easily crushed when a load is applied during molding. .
  • JP 2003-160682 A Japanese Patent Publication No. 8-16175 JP 2012-022089 A
  • An object of the present invention is to solve the above-described problems and provide a white polyester film for molding and a white resin molded article suitable for a direct type backlight unit.
  • a white polyester film for molding comprising at least three layers, a glass transition temperature (Tg) of a surface layer of 80 ° C. or higher and 120 ° C. or lower, and a specific gravity of the film of 0.8 to 1.1.
  • Tg glass transition temperature
  • E ′ storage elastic modulus
  • the white polyester film for molding (3) comprising at least three layers, the core
  • the reflectance is 98% or more and the transmittance is less than 3% (1) to a white polyester film for molding according to any one of (3) (5) a white resin molded article obtained by molding the white polyester film for molding according to any one of (1) to (4) )
  • the white resin molded product according to (5) which is used for a direct type LED backlight unit.
  • a white polyester film excellent in moldability and shape retention after molding can be provided, and a white resin molded article suitable for a direct type backlight unit with less luminance unevenness can be provided by molding the white polyester film. can do.
  • the present inventors have found that it is important not only to have high reflectivity and moldability but also to have high shape maintainability in order to obtain a reflector having a shape.
  • the present invention has been made.
  • a reflecting plate formed to improve the contrast ratio of the direct type backlight unit and eliminate unevenness is applied, its shape is optically optimized by precise calculation. After the reflector is incorporated in the direct type backlight unit, it is exposed to heat generated from an electric circuit or LED. At this time, if the reflecting plate cannot maintain its shape, the effect of improving the contrast ratio and eliminating the unevenness will be reduced.
  • the glass transition temperature (Tg) of the surface layer is at least 80 ° C. and less than 120 ° C., and the specific gravity of the film is 0.8 to 1.1. If the white polyester film for molding characterized by this is used, the white polyester for molding excellent in moldability and shape retention can be provided.
  • the white polyester film for molding of the present invention is composed of at least three layers, and the glass transition temperature (Tg) of the surface layer is required to be 80 ° C. or higher and lower than 120 ° C.
  • the glass transition temperature is defined as 10 ° C./min.
  • DSC differential scanning calorimeter
  • the glass transition temperature is 85 ° C. or higher and lower than 115 ° C., and further preferably 90 ° C. or higher and lower than 110 ° C.
  • the laminated form of the molding white polyester of the present invention is not particularly limited as long as it is three or more layers. For example, when one layer is represented by one alphabetic character, a laminated form such as X / Y / X, X / Y / Z, etc. Can be mentioned. When both surface layers are layers made of different raw materials, it is necessary that both surface layers have a glass transition temperature (Tg) of 80 ° C. or higher and lower than 120 ° C.
  • Tg glass transition temperature
  • the glass transition temperature (Tg) of a surface layer Inclusion of resin with a glass transition temperature of 80 degreeC or more in a surface layer is mentioned.
  • the resin having a glass transition temperature of 80 ° C. or higher is preferably a polyester resin, more preferably an aromatic polyester resin.
  • the white polyester film for molding of the present invention needs to have a polyester resin as a main component. Of the resins constituting the white polyester film for molding, if the polyester resin is at least 50% by weight or more, it can be said to be the main component. About a polyester resin, a preferable aspect is described below.
  • the polyester resin refers to a polymer having an ester bond in the main chain
  • the polyester resin used in the present invention is preferably a polyester resin having a structure obtained by condensation polymerization of dicarboxylic acid and diol.
  • the dicarboxylic acid component include, for example, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid, and 5-sodium sulfone.
  • Aromatic dicarboxylic acids such as dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids And oxycarboxylic acids such as paraoxybenzoic acid.
  • dicarboxylic acid ester derivative components esterified products of the above dicarboxylic acid compounds, such as dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, adipic acid
  • the components include dimethyl, diethyl maleate, and dimethyl dimer.
  • terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferably main components in order to bring the glass transition temperature into the above range.
  • dicarboxylic acid components are 50 mol% or more of the dicarboxylic acid components, it can be said that they are the main components.
  • the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -Aliphatic dihydroxy compounds such as hexanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,4 -Cyclohexanedimethanol, spiroglycol, alicyclic dihydroxy compounds such as 1,4: 3,6-dianhydro-D-glucitol (isosorbide), aromatic dihydroxy compounds such as bisphenol A and bisphenol S,
  • trimellitic acid, pyromellitic acid and an ester derivative thereof may be copolymerized in a small amount.
  • the main component of the diol component is ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, spiroglycol, and isosorbide, which adjusts the storage elastic modulus (E ′) described later. This is preferable.
  • the white polyester film for molding of the present invention needs to have a specific gravity of 0.8 to 1.1.
  • a method for setting the specific gravity in such a range it is preferable to contain bubbles in the film.
  • a method of incorporating bubbles inside (1) a method in which a foaming agent is contained in a polyester resin and foamed by heating during extrusion or film formation or foamed by chemical decomposition to form bubbles, (2) polyester (3) Adding inorganic particles and / or thermoplastic resin (A) incompatible with the resin to the polyester resin, and uniaxially or biaxially stretching it.
  • A thermoplastic resin
  • the inorganic particles are particularly preferable because film formation stability can be obtained with high optical characteristics.
  • the inorganic particles are preferably contained in an amount of 1 to 50% by weight based on the total weight of the white polyester film for molding of the present invention.
  • the amount of inorganic particles is less than 1% by weight, it is difficult to make the specific gravity 1.1 or less.
  • the amount is more than 50% by weight, the mechanical strength, heat resistance and production cost of the polyester resin may be impaired, which is not preferable.
  • the thermoplastic resin incompatible with the polyester resin (A) is an olefin resin such as polyethylene, polypropylene, polybutene, polymethylpentene, or cyclic olefin, styrene resin, polyacrylate resin, polycarbonate resin, polyacrylonitrile resin, Polyphenylene sulfide resin, fluorine resin, etc. are selected. Of these, an olefin resin or a styrene resin is preferable.
  • the olefin resin include polyethylene, polypropylene, and poly-4-methylpentene-1 (hereinafter, may be abbreviated as “polymethylpentene” or “PMP”).
  • Ethylene-propylene copolymer, ethylene-butene-1 copolymer, and cyclic olefin, and polystyrene, polymethylstyrene, polydimethylstyrene and the like are preferable as the styrene resin.
  • These may be a homopolymer or a copolymer, and two or more thermoplastic resins (A) may be used in combination.
  • the thermoplastic resin (A) is preferably contained in an amount of 1 to 50% by weight based on the total weight of the white polyester film for molding of the present invention.
  • the specific gravity is 0.82 to 1.05, and more preferably 0.85 to 1.0.
  • thermoplastic resin (A) As a technique for obtaining the weight ratio of the polyester resin and the thermoplastic resin (A), a technique in which a plurality of analyzes are combined depending on the type of each resin can be considered. A method in which only the polyester resin is removed with a solvent, and the remaining thermoplastic resin (A) is separated by a centrifuge, and the weight ratio is obtained from the weight of the resulting residue, IR (infrared spectroscopy), 1H-NMR After identifying each resin by 13C-NMR, the polyester resin and the thermoplastic resin (A) are both dissolved in a soluble solvent, impurities and inorganic substances are removed by centrifugation, and the concentration is determined by absorbance. A method for determining the weight ratio can be used. Examples of solvents that can dissolve the polyester resin include trifluoroacetic acid, 1,1,1,3,3,3-hexafluoro-2-propanol, o-chlorophenol, and the like.
  • the white polyester film for molding according to the present invention preferably has a storage elastic modulus (E ′) at a glass transition temperature (Tg) + 60 ° C. of the surface layer of 10 MPa or more and 300 MPa or less. If the storage elastic modulus (E ') at a certain temperature is small, it indicates that it is easy to deform with a small force at that temperature, and if it is large, it indicates that a large force is required for deformation. When the storage elastic modulus (E ′) at the glass transition temperature (Tg) + 60 ° C. of the surface layer is lower than 10 MPa, the self-supporting property may be lowered due to the film's own weight, which is not preferable.
  • molding for providing a specific shape since it will become difficult for the shaping
  • the storage elastic modulus can be adjusted to the above-mentioned range by producing a film by the method described below after combining the methods such as setting the ratio to 1.1 or less.
  • two or more of the copolymer polyesters listed as the dicarboxylic acid component of the polyester resin and / or two or more of the copolymer polyesters listed as the diol component are copolymerized.
  • a combination of terephthalic acid and 2,6-naphthalenedicarboxylic acid and a combination of ethylene glycol and spiroglycol are preferable because the glass transition temperature is easily set to 80 ° C. or higher and 120 ° C. or lower as compared with polyethylene terephthalate homopolymer.
  • a copolymer component may be added at the time of polymerization of a raw material polyester pellet, and the copolymer component may be used as a pellet in which a copolymer component has been polymerized in advance.
  • a copolymer component may be used as a pellet in which a copolymer component has been polymerized in advance.
  • polyethylene naphthalate is used.
  • a method may be used in which a mixture of pellets independently polymerized and polyethylene terephthalate pellets is supplied to an extruder and copolymerized by transesterification at the time of melting.
  • the polyester resin used for the surface layer of the molding white polyester film of the present invention may be a mixture of two or more kinds of polyester resins.
  • two or more glass transition temperatures of the surface layer may be measured.
  • the glass transition temperature that is the starting point of “the glass transition temperature of the surface layer + 60 ° C.” is the glass transition temperature having the highest temperature.
  • the white polyester film for molding of the present invention preferably has bubbles containing a void nucleating agent in the core layer.
  • a core layer here refers to all the layers except the both surface layers in a polyester film of three or more layers. In the case of four or more layers, there are two or more core layers. When there are two or more core layers, it is preferable that at least any one layer has bubbles containing a void nucleating agent.
  • the void nucleating agent is not the same as the main resin component constituting the white polyester film for molding, and may be any material that can be dispersed in the resin component, for example, inorganic fine particles, organic fine particles, various thermoplastic resins, etc. Is mentioned.
  • the method for obtaining bubbles containing a void nucleating agent is not particularly limited, but inorganic particles and / or a thermoplastic resin (A) incompatible with the resin is added to the polyester resin, and the resultant is uniaxially or biaxially stretched. A method of generating fine bubbles by doing so is preferably used. Due to having voids containing void nucleating agent, voids are not easily crushed during molding, and when white polyester film for molding is molded into a white resin molded body, the reflectance decreases and the transmittance increases. Is preferable because it is difficult to occur.
  • the white polyester film for molding of the present invention preferably has a reflectance of 98% or more and a transmittance of less than 3%.
  • the reflectance here refers to the average reflectance in the wavelength region of 400 to 700 nm of light, and the transmittance conforms to JIS-K-7361-1 using light in the wavelength of visible light region (400 to 800 nm). It is the transmittance of light measured in this way. Sometimes referred to as total light transmittance. When the reflectance is less than 98% or the transmittance is 3% or more, sufficient luminance may not be obtained when it is incorporated in a direct type backlight, which is not preferable.
  • a method for setting the reflectance and transmittance within the above ranges is not particularly limited, but inorganic particles and / or a thermoplastic resin (A) incompatible with the resin is added to the polyester resin, and the resultant is uniaxially or biaxially.
  • a method of generating fine bubbles by axial stretching is preferably used.
  • the white polyester film for molding of the present invention has a film thickness of 100 to 500 ⁇ m in order to make the film forming property, moldability viewpoint, reflection / transmittance, and shape retention with respect to the load after molding into a preferable range. Preferably, it is 125 to 400 ⁇ m, more preferably 160 to 350 ⁇ m.
  • the main extruder has a resin as a raw material for the core layer (Y), and the sub-extruder has a surface layer (X).
  • Each raw material is preferably dried so that the moisture content is 50 ppm or less.
  • the raw materials are supplied to each extruder and, for example, a three-layer laminated film of X / Y / X can be formed by using two extruders and a feed block or a multi-manifold installed on the top of the T die.
  • the extruded unstretched sheet is closely cooled and solidified on a cooled drum to obtain an unstretched laminated film.
  • a target polyester film is obtained through a stretching step and a heat treatment step.
  • This unstretched film is heated to a temperature higher than the glass transition temperature (Tg) of the polymer by roll heating or infrared heating as necessary, and stretched in the longitudinal direction (hereinafter referred to as the longitudinal direction) to obtain a longitudinally stretched film.
  • Tg glass transition temperature
  • This stretching is performed by utilizing the difference in peripheral speed between two or more rolls.
  • the longitudinal stretch ratio is preferably 2 to 6 times, more preferably 3 to 4 times, although it depends on the required properties of the application. If it is less than 2 times, the reflectance may be low, and if it exceeds 6 times, breakage may easily occur during film formation.
  • the film after longitudinal stretching is then subjected to stretching, heat setting, and thermal relaxation in the direction perpendicular to the longitudinal direction (hereinafter referred to as the transverse direction) to form a biaxially oriented film. While running.
  • preheating and stretching temperature for transverse stretching are preferably performed at a glass transition temperature (Tg) or higher (Tg + 20 ° C.) of the polymer.
  • Tg glass transition temperature
  • the transverse stretching ratio is preferably 2.5 to 6 times, more preferably 3 to 4 times, although it depends on the required characteristics of the application. If it is less than 2.5 times, the reflectance may be low. If it exceeds 6 times, breakage may easily occur during film formation.
  • the obtained biaxially stretched laminated film In order to complete the crystal orientation of the obtained biaxially stretched laminated film and to impart flatness and dimensional stability, it is then subjected to heat treatment at a temperature of 180 to 230 ° C. for 1 to 60 seconds in a tenter, and uniform After cooling slowly, it is cooled to room temperature and wound on a roll.
  • the heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction.
  • the polyester film of the present invention may be stretched by any of the sequential biaxial stretching method and the simultaneous biaxial stretching method. If necessary, after the biaxial stretching, re-longitudinal stretching and / or re-lateral stretching may be performed.
  • various kinds of techniques can be used by using a well-known technique in order to impart slipperiness, antistatic property, ultraviolet light absorption performance, etc. to at least one surface of the resin layer (A) as long as the effects of the present invention are not impaired.
  • a hard coat layer or the like may be provided in order to apply a coating liquid or improve impact resistance. The coating may be performed at the time of film production (in-line coating), or may be performed on a white film after film production (off-line coating).
  • the present invention may be a white resin molded body obtained by molding the white polyester film for molding described above.
  • the forming method is not particularly limited, but a method of forming only a film, such as vacuum forming, pressure forming, vacuum pressure forming, press forming, plug assist vacuum pressure forming, insert molding, TOM (Three dimension Overlay Method) forming, tertiary It can be formed by a generally known forming method such as a forming method with a base material such as original laminate forming. For example, when vacuum / pressure forming is performed, the film is heated with a far-infrared heater at 400 ° C. so that the film surface temperature becomes Tg + 50 ° C.
  • the shape of the molded body of the present invention is not particularly limited, but it is preferable that one or more dents are formed.
  • the shape of the dent may be a frustum shape, a hemispherical shape, a spherical crown shape, a columnar shape, a combination thereof, an intermediate shape, a shape that is distorted like an ellipse, or a rounded shape with an R at a corner.
  • a quadrangular frustum shape or a hexagonal frustum shape is preferable because it is easy to fill the surface with the same shape and is easy to use for the use described later.
  • the white resin molded product of the present invention can be suitably used as a reflector for an LED lighting unit.
  • an LED lighting unit using the white resin molded body of the present invention light leakage of adjacent LEDs hardly occurs, which is preferable as an illumination application equipped with a partial drive function. It is particularly preferable as a reflector for a flat LED lighting unit.
  • the white resin molded product of the present invention can be suitably used as a reflector for a direct type LED backlight unit.
  • a direct type LED backlight unit using the reflector of the present invention light leakage of adjacent LEDs hardly occurs, which is preferable for a backlight equipped with a local dimming function.
  • a reflector for a direct type LED backlight unit used for a liquid crystal display, a liquid crystal television, a liquid crystal monitor, and the like is preferable as a reflector for a direct type LED backlight unit used for a liquid crystal display, a liquid crystal television, a liquid crystal monitor, and the like.
  • Test force 15N or more was read from the obtained SS curve, and load resistance was evaluated from the test force (N).
  • ⁇ Test force 15N or more
  • ⁇ Test force 10N or more and less than 15N
  • ⁇ Test force 5N or more and less than 10N
  • x Test force Less than 5N ⁇ or more was regarded as acceptable.
  • Polyester resin (a) Polymerization was carried out from terephthalic acid and ethylene glycol by a conventional method using antimony trioxide as a catalyst to obtain polyethylene terephthalate (PET).
  • PET polyethylene terephthalate
  • the obtained PET has a glass transition temperature of 77 ° C., a melting point of 255 ° C., an intrinsic viscosity of 0.63 dl / g, and a terminal carboxyl group concentration of 40 eq. / T.
  • Polyester resin (b) A transesterification reaction was carried out from dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol using manganese acetate as a catalyst. After the transesterification reaction, polyethylene naphthalate (PEN) was obtained by a conventional method using antimony trioxide as a catalyst. The obtained PEN had a glass transition temperature of 124 ° C., a melting point of 265 ° C., an intrinsic viscosity of 0.62 dl / g, and a terminal carboxyl group concentration of 25 eq. / T.
  • PEN polyethylene naphthalate
  • Copolyester resin (c) A commercially available 1,4-cyclohexanedimethanol copolymerized polyester (GN001 manufactured by Eastman Chemical Co.) was used. The glass transition temperature was 85 ° C. and the intrinsic viscosity was 0.75 dl / g.
  • Copolyester resin (e) A neopentyl glycol copolymer polyethylene terephthalate resin having a terephthalic acid component of 100 mol% as a dicarboxylic acid component, an ethylene glycol component of 70 mol% and a neopentyl glycol component of 30 mol% as a glycol component was used. The intrinsic viscosity was 0.75 dl / g.
  • Polyester resin (f) A commercially available polybutylene terephthalate resin, “Toraycon” (registered trademark) 1200S manufactured by Toray Industries, Inc. was used. The melting point was 224 ° C. and the intrinsic viscosity was 1.26 dl / g.
  • Copolyester resin (g) A commercially available spiroglycol copolymer polyester resin, “Altester” (registered trademark) S2000 manufactured by Mitsubishi Gas Chemical Company, Inc. was used. The glass transition temperature was 95 ° C. and the intrinsic viscosity was 0.75 dl / g.
  • Copolyester resin (h) Commercially available isophthalic acid copolymerized polycyclohexanedimethylene terephthalate (Eastman CHEMICAL "Eastar AN004") was used. The glass transition temperature was 83 ° C. and the intrinsic viscosity was 0.75 dl / g.
  • Titanium dioxide master i) 50 parts by weight of polyester resin (a) and 50 parts by weight of titanium dioxide particles (number average particle size 0.5 ⁇ m) were kneaded with a twin screw extruder to obtain titanium dioxide master pellets (k).
  • Thermoplastic resin j) Commercially available polymethylpentene raw material “TPX RT18” (Mitsui Chemicals, Inc., melting point 233 ° C.)
  • Cyclic olefin resin k
  • a commercially available cyclic olefin resin “TOPAS 6017” was used.
  • Examples 1, 3 to 7, 9 After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material for the core layer (Y) was supplied to the main extruder, melt-extruded at a temperature of 280 ° C., and filtered through a 30 ⁇ m cut filter. The raw material of the surface layer (X) is supplied to the extruder, melt-extruded at a temperature of 290 ° C., filtered through a 30 ⁇ m cut filter, and then the surface layer (X) is the both surface layers of the core layer (Y) in the T-die composite die. To be laminated (X / Y / X).
  • the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film.
  • the unstretched film was preheated with a roll group heated to a temperature of 80 ° C., and then stretched at a magnification in Table 2 in the longitudinal direction (longitudinal direction) while being irradiated from both sides with an infrared heater, and 25 ° C.
  • a uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C.
  • preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C.
  • heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
  • Example 2 After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material for the core layer (Y) was supplied to the main extruder and the raw material for the surface layer (X) was supplied to the sub-extruder. After melt extrusion at a temperature, after filtration through a 30 ⁇ m cut filter, the surface layer (X) was joined to be laminated (X / Y / X) on both surface layers of the core layer (Y) in a T-die composite die. .
  • the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film.
  • the unstretched film was preheated with a roll group heated to a temperature of 70 ° C., and then stretched at a magnification of Table 2 in the longitudinal direction (longitudinal direction) while irradiating from both sides with an infrared heater.
  • a uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C.
  • preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C.
  • heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
  • Example 10 After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material of the core layer (Y) was supplied to the main extruder, and after melt extrusion at a temperature of 280 ° C., filtration was performed with a 30 ⁇ m cut filter. The raw material of the surface layer (X) is supplied to the sub-extruder, melt-extruded at a temperature of 270 ° C., filtered through a 30 ⁇ m cut filter, and then the surface layer (X) is the core layer (Y) in the T-die composite die. It was made to merge so that it might be laminated
  • the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film.
  • the unstretched film was preheated with a roll group heated to a temperature of 70 ° C., and then stretched at a magnification of Table 2 in the longitudinal direction (longitudinal direction) while irradiating from both sides with an infrared heater.
  • a uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C.
  • preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C.
  • heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
  • the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film.
  • the unstretched film was preheated with a roll group heated to a temperature of 70 ° C., and then stretched at a magnification of Table 2 in the longitudinal direction (longitudinal direction) while irradiating from both sides with an infrared heater.
  • a uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C.
  • the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film.
  • the unstretched film was preheated with a roll group heated to a temperature of 80 ° C., and then stretched at a magnification in Table 2 in the longitudinal direction (longitudinal direction) while being irradiated from both sides with an infrared heater, and 25 ° C.
  • a uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C.
  • preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C.
  • heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
  • the present invention has not only high reflectivity and moldability but also high shape maintainability, it is suitably used as a light reflector used in a direct type LED backlight unit.

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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
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  • General Engineering & Computer Science (AREA)
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Abstract

[Problem] To provide a white resin molded body that is suitable for a direct-under type backlight unit, or a white polyester film that is suitably processed to be the white resin molded body. [Solution] This white polyester film for molding is characterized by comprising at least three layers, wherein the glass transition temperature (Tg) of the surface layer is 80-120°C, and the specific gravity of the film is 0.8-1.1.

Description

成形用白色ポリエステルフィルム及びそれを用いた白色樹脂成形体White polyester film for molding and white resin molded body using the same
本発明は、直下型バックライトユニットなどとして好適に用いられる成形用白色ポリエステルフィルム及び白色樹脂成形体に関するものである。 The present invention relates to a white polyester film for molding and a white resin molded article that are suitably used as a direct type backlight unit.
近年、パソコン、テレビ、スマートフォン、タブレット、携帯電話などの表示装置として、液晶を利用したディスプレイが数多く用いられている。これらの液晶ディスプレイは、それ自体は発光体でないために、裏側からバックライトと呼ばれる面光源を設置して光を照射することにより表示が可能となっている。また、バックライトは、単に光を照射するだけでなく、画面全体を均一に照射せねばならないという要求に応えるため、エッジライト型もしくは直下型と呼ばれる面光源の構造をとっている。なかでも、薄型・小型化が望まれるノート型パソコンやモニター、タブレット等に使用される薄型液晶ディスプレイ用途には、エッジライト型、つまり画面に対し側面から光を照射するタイプのバックライトが適用されている。一方、液晶テレビのような大画面用では、直下型、つまり画面に対し裏面から光を照射するタイプのバックライトが適用されている。　 In recent years, many displays using liquid crystals have been used as display devices for personal computers, televisions, smartphones, tablets, mobile phones and the like. Since these liquid crystal displays themselves are not light emitters, they can be displayed by installing a surface light source called a backlight from the back side and irradiating light. Further, the backlight has a structure of a surface light source called an edge light type or a direct type in order to meet the demand for not only irradiating light but also irradiating the entire screen uniformly. In particular, for thin liquid crystal display applications used in notebook computers, monitors, tablets, etc., where thinness and miniaturization are desired, edge-light type backlights that irradiate light from the side are applied. ing. On the other hand, for a large screen such as a liquid crystal television, a backlight of a direct type, that is, a type of irradiating light from the back surface to the screen is applied. *
　このような液晶画面用の面光源に用いられるランプリフレクターや反射板（以下、反射フィルム、面光源反射部材などと総称することもある）には、高い光反射性能が要求され、従来、白色顔料を添加したフィルムや内部に微細な気泡を含有させたフィルムが単独で、もしくはこれらのフィルムと金属板、プラスチック板などを張り合わせたものが使用されてきた。特に内部に微細な気泡を含有させたフィルムは、輝度の向上効果や、画面輝度の均一化に一定の効果があることから広く使用されている（特許文献１、２）。
直下型バックライトを搭載した大型テレビでは、「ローカルディミング」と言われる機能が搭載される。液晶バックライトを細かく区分し、表示する画像の明暗に合わせてバックライトを区分ごとに明暗をつけることで、よりコントラストを高く、きれいな画像を表示することができる技術である。「ローカルディミング」の技術的課題として、隣り合うＬＥＤの明暗の差が大きい場合、光が隣の領域まで漏れてしまい、効果が薄れるというものがあった。また、直下型バックライトでは、構成によってはＬＥＤがある部分だけ明るくなるムラが生じる場合があった。
これらの課題を解決する手法として、凹状の光反射面が形成されている光反射板（特許文献３）などが使用できるが、発泡シートは成形時に負荷がかかるとボイドが潰れやすいという課題がある。 Lamp reflectors and reflectors used in such surface light sources for liquid crystal screens (hereinafter sometimes collectively referred to as reflective films, surface light source reflecting members, etc.) are required to have high light reflection performance. A film to which is added, a film containing fine bubbles inside, or a film obtained by bonding these films to a metal plate, a plastic plate or the like has been used. In particular, a film containing fine bubbles inside is widely used because it has a certain effect in improving luminance and uniforming screen luminance (Patent Documents 1 and 2).
Large TVs with direct backlights are equipped with a function called “local dimming”. This is a technology that can display a clear image with higher contrast by finely dividing the liquid crystal backlight and lighting the backlight in accordance with the brightness of the image to be displayed. As a technical problem of “local dimming”, when the difference in brightness between adjacent LEDs is large, light leaks to the adjacent region, and the effect is reduced. Further, in the direct type backlight, depending on the configuration, there may be unevenness in which only a portion where the LED is present becomes bright.
As a method for solving these problems, a light reflecting plate (Patent Document 3) on which a concave light reflecting surface is formed can be used. However, a foam sheet has a problem that voids are easily crushed when a load is applied during molding. .
特開２００３－１６０６８２号公報JP 2003-160682 A 特公平８－１６１７５号公報Japanese Patent Publication No. 8-16175 特開２０１２－０２２０８９号公報JP 2012-022089 A
　本発明は、上記の問題を解決し、直下型バックライトユニットに好適な成形用白色ポリエステルフィルム及び白色樹脂成形体を提供することを目的とするものである。 An object of the present invention is to solve the above-described problems and provide a white polyester film for molding and a white resin molded article suitable for a direct type backlight unit.
本発明者らは、係る課題について鋭意検討した結果以下の構成を有する。
（１）少なくとも三層からなり、表層のガラス転移温度（Ｔｇ）が８０℃以上１２０℃以下であり、フィルムの比重が０．８～１．１であることを特徴とする成形用白色ポリエステルフィルム
（２）表層のガラス転移温度（Ｔｇ）+６０℃における貯蔵弾性率（Ｅ’）が１０ＭＰａ以上３００ＭＰａ以下である（１）に記載の成形用白色ポリエステルフィルム
（３）少なくとも三層からなり、芯層にボイド核剤を含有する気泡を有していることを特徴とする（１）または（２）に記載の成形用白色ポリエステルフィルム
（４）反射率９８％以上かつ透過率３％未満である（１）～（３）のいずれかに記載の成形用白色ポリエステルフィルム
（５）（１）～（４）のいずれかに記載の成形用白色ポリエステルフィルムを成形した白色樹脂成形体
（６）ＬＥＤ照明ユニットに使用される（５）に記載の白色樹脂成形体。
（７）直下型ＬＥＤバックライトユニットに使用される（５）に記載の白色樹脂成形体。 The inventors of the present invention have the following configurations as a result of intensive studies on such problems.
(1) A white polyester film for molding comprising at least three layers, a glass transition temperature (Tg) of a surface layer of 80 ° C. or higher and 120 ° C. or lower, and a specific gravity of the film of 0.8 to 1.1. (2) The glass transition temperature (Tg) of the surface layer + the storage elastic modulus (E ′) at 60 ° C. is 10 MPa or more and 300 MPa or less (1) The white polyester film for molding (3) comprising at least three layers, the core The white polyester film for molding as described in (1) or (2), wherein the layer has bubbles containing a void nucleating agent (4) The reflectance is 98% or more and the transmittance is less than 3% (1) to a white polyester film for molding according to any one of (3) (5) a white resin molded article obtained by molding the white polyester film for molding according to any one of (1) to (4) ) White resin molded article according to be used in the LED lighting unit (5).
(7) The white resin molded product according to (5), which is used for a direct type LED backlight unit.
本発明によれば、成形性と成形後の形状保持に優れた白色ポリエステルフィルムを提供でき、その白色ポリエステルフィルムを成形することで輝度ムラの少ない直下型バックライトユニットに好適な白色樹脂成形体提供することができる。 According to the present invention, a white polyester film excellent in moldability and shape retention after molding can be provided, and a white resin molded article suitable for a direct type backlight unit with less luminance unevenness can be provided by molding the white polyester film. can do.
得られたＳ－Ｓカーブから弾性変形と塑性変形の境界を表す図面Drawing showing boundary between elastic deformation and plastic deformation from obtained SS curve
　本発明者らは、係る課題について鋭意検討した結果、形状を付与した反射板を得るには、高い反射率と成形性を備えるのみならず、高い形状維持性を持つことが重要であることを究明し、本発明をなすに到った。直下型バックライトユニットのコントラスト比を向上し、ムラを消すために成形された反射板を適用する場合、その形状は緻密な計算により光学的に最適化されたものである。反射板は、直下型バックライトユニットに組み込んだ後、電気回路やＬＥＤから出る熱にさらされる。その際、反射板が形状を保持できなければ、コントラスト比の向上やムラ消しの効果が薄れることになる。 As a result of earnestly examining the problem, the present inventors have found that it is important not only to have high reflectivity and moldability but also to have high shape maintainability in order to obtain a reflector having a shape. As a result, the present invention has been made. When a reflecting plate formed to improve the contrast ratio of the direct type backlight unit and eliminate unevenness is applied, its shape is optically optimized by precise calculation. After the reflector is incorporated in the direct type backlight unit, it is exposed to heat generated from an electric circuit or LED. At this time, if the reflecting plate cannot maintain its shape, the effect of improving the contrast ratio and eliminating the unevenness will be reduced.
　本発明者らが鋭意検討したところによれば、少なくとも三層からなり、表層のガラス転移温度（Ｔｇ）が８０℃以上１２０℃未満であり、フィルムの比重が０．８～１．１であることを特徴とする成形用白色ポリエステルフィルムを用いれば、成形性と形状保持性に優れた成形用白色ポリエステルを供することができる。 According to the earnest study by the present inventors, the glass transition temperature (Tg) of the surface layer is at least 80 ° C. and less than 120 ° C., and the specific gravity of the film is 0.8 to 1.1. If the white polyester film for molding characterized by this is used, the white polyester for molding excellent in moldability and shape retention can be provided.
　以下に本発明の詳細を記載する。
[フィルム構成]
　本発明の成形用白色ポリエステルフィルムは、少なくとも三層からなり、表層のガラス転移温度（Ｔｇ）が８０℃以上１２０℃未満であることが必要である。
ガラス転移温度とは、ポリマーを示差走査型熱量計（ＤＳＣ）において窒素雰囲気下、１０℃／ｍｉｎ．の昇温速度で測定したときの、比熱容量変化を伴う階段状吸熱ピークの中点の温度のことをいう。表層のガラス転移温度が８０℃より低いと、フィルムを成形した後の形状保持性が低下する場合があり好ましくない。また、１２０℃より高い場合、加工性が悪化する場合があり好ましくない。より好ましくは、ガラス転移温度が８５℃以上１１５℃未満であり、さらに好ましくは９０℃以上１１０℃未満である。
本発明の成形用白色ポリエステルの積層形態は、三層以上であれば特に限定されないが、たとえば１層をアルファベット一文字で表した場合、Ｘ／Ｙ／Ｘ、Ｘ／Ｙ／Ｚなどの積層形態を挙げることができる。両表層が異なる原料からなる層である場合、いずれの表層もガラス転移温度（Ｔｇ）が８０℃以上１２０℃未満であることが必要である。
表層のガラス転移温度（Ｔｇ）を上記の範囲にする方法としては、特に限定されるものではないが、ガラス転移温度が８０℃以上である樹脂を表層に含有せしめることが挙げられる。ガラス転移温度が８０℃以上である樹脂はポリエステル樹脂であることが好ましく、さらに好ましくは芳香族ポリエステル樹脂である。
本発明の成形用白色ポリエステルフィルムは、ポリエステル樹脂を主成分としている必要がある。成形用白色ポリエステルフィルムを構成する樹脂のうち、ポリエステル樹脂が少なくとも５０重量％以上であれば、主成分といえる。ポリエステル樹脂について、好ましい態様を以下に記載する。ポリエステル樹脂とはエステル結合を主鎖に持つ高分子をいうが、本発明に用いるポリエステル樹脂は、ジカルボン酸とジオールとが縮重合した構造を持つポリエステル樹脂が好ましい。ジカルボン酸成分としては、例えば、芳香族ジカルボン酸では、テレフタル酸、イソフタル酸、フタル酸、２，６－ナフタレンジカルボン酸、ジフェニルジカルボン酸、ジフェニルスルホンジカルボン酸、ジフェノキシエタンジカルボン酸、５－ナトリウムスルホンジカルボン酸などの芳香族ジカルボン酸、シュウ酸、コハク酸、アジピン酸、セバシン酸、ダイマー酸、マレイン酸、フマル酸などの脂肪族ジカルボン酸、１，４－シクロヘキサンジカルボン酸などの脂環族ジカルボン酸、パラオキシ安息香酸などのオキシカルボン酸などの各成分を挙げることができる。また、ジカルボン酸エステル誘導体成分として、上記ジカルボン酸化合物のエステル化物、たとえばテレフタル酸ジメチル、テレフタル酸ジエチル、テレフタル酸２－ヒドロキシエチルメチルエステル、２，６－ナフタレンジカルボン酸ジメチル、イソフタル酸ジメチル、アジピン酸ジメチル、マレイン酸ジエチル、ダイマー酸ジメチルなどの各成分を挙げることができる。ジカルボン酸成分としては、テレフタル酸、イソフタル酸、２，６－ナフタレンジカルボン酸が主成分であることが、ガラス転移温度を上記の範囲とするために好ましい。これらのジカルボン酸成分が、ジカルボン酸成分のうち５０モル％以上であれば主成分であるといえる。
また、ジオール成分としては、例えば、エチレングリコール、１，２－プロパンジオール、１，３－プロパンジオール、１，３－ブタンジオール、１，４－ブタンジオール、１，５－ペンタンジオール、１，６－ヘキサンジオール、２，２－ジメチル－１，３－プロパンジオール（ネオペンチルグリコール）などの脂肪族ジヒドロキシ化合物、ジエチレングリコール、ポリエチレングリコール、ポリプロピレングリコール、ポリテトラメチレングリコールなどのポリオキシアルキレングリコール、１，４－シクロヘキサンジメタノール、スピログリコール、１，４：３，６－ジアンヒドロ－Ｄ－グルシトール（イソソルビド）などの脂環族ジヒドロキシ化合物、ビスフェノールＡ、ビスフェノールＳなどの芳香族ジヒドロキシ化合物など各成分が挙げられる。これらはそれぞれ１種だけであっても２種以上用いられるものであっても良い。また、フィルムとして製膜性に影響が出なければまたトリメリット酸、ピロメリット酸およびそのエステル誘導体を少量共重合されたものであっても構わない。ジオール成分としては、エチレングリコール、１，４－ブタンジオール、ネオペンチルグリコール、１，４－シクロヘキサンジメタノール、スピログリコール、イソソルビドが主成分であることが、後述する貯蔵弾性率（Ｅ’）を調整する上で好ましい。 Details of the present invention will be described below.
[Film composition]
The white polyester film for molding of the present invention is composed of at least three layers, and the glass transition temperature (Tg) of the surface layer is required to be 80 ° C. or higher and lower than 120 ° C.
The glass transition temperature is defined as 10 ° C./min. In a nitrogen atmosphere in a differential scanning calorimeter (DSC). The temperature at the midpoint of the step-like endothermic peak with a change in specific heat capacity when measured at a rate of temperature increase. If the glass transition temperature of the surface layer is lower than 80 ° C., the shape retention after forming the film may be lowered, which is not preferable. Moreover, when higher than 120 degreeC, workability may deteriorate and it is unpreferable. More preferably, the glass transition temperature is 85 ° C. or higher and lower than 115 ° C., and further preferably 90 ° C. or higher and lower than 110 ° C.
The laminated form of the molding white polyester of the present invention is not particularly limited as long as it is three or more layers. For example, when one layer is represented by one alphabetic character, a laminated form such as X / Y / X, X / Y / Z, etc. Can be mentioned. When both surface layers are layers made of different raw materials, it is necessary that both surface layers have a glass transition temperature (Tg) of 80 ° C. or higher and lower than 120 ° C.
Although it does not specifically limit as a method of making the glass transition temperature (Tg) of a surface layer into said range, Inclusion of resin with a glass transition temperature of 80 degreeC or more in a surface layer is mentioned. The resin having a glass transition temperature of 80 ° C. or higher is preferably a polyester resin, more preferably an aromatic polyester resin.
The white polyester film for molding of the present invention needs to have a polyester resin as a main component. Of the resins constituting the white polyester film for molding, if the polyester resin is at least 50% by weight or more, it can be said to be the main component. About a polyester resin, a preferable aspect is described below. The polyester resin refers to a polymer having an ester bond in the main chain, and the polyester resin used in the present invention is preferably a polyester resin having a structure obtained by condensation polymerization of dicarboxylic acid and diol. Examples of the dicarboxylic acid component include, for example, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid, and 5-sodium sulfone. Aromatic dicarboxylic acids such as dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids And oxycarboxylic acids such as paraoxybenzoic acid. Further, as dicarboxylic acid ester derivative components, esterified products of the above dicarboxylic acid compounds, such as dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, adipic acid Examples of the components include dimethyl, diethyl maleate, and dimethyl dimer. As the dicarboxylic acid component, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferably main components in order to bring the glass transition temperature into the above range. If these dicarboxylic acid components are 50 mol% or more of the dicarboxylic acid components, it can be said that they are the main components.
Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -Aliphatic dihydroxy compounds such as hexanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,4 -Cyclohexanedimethanol, spiroglycol, alicyclic dihydroxy compounds such as 1,4: 3,6-dianhydro-D-glucitol (isosorbide), aromatic dihydroxy compounds such as bisphenol A and bisphenol S, etc. And the like. These may be used alone or in combination of two or more. Moreover, as long as film forming property is not affected as a film, trimellitic acid, pyromellitic acid and an ester derivative thereof may be copolymerized in a small amount. The main component of the diol component is ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, spiroglycol, and isosorbide, which adjusts the storage elastic modulus (E ′) described later. This is preferable.
　本発明の成形用白色ポリエステルフィルムは、比重が０．８～１．１である必要がある。比重をかかる範囲とする手法として、フィルムの内部に気泡を含有させることが好ましい。内部に気泡を含有させる方法としては、（１）ポリエステル樹脂に発泡剤を含有せしめ、押出や製膜時の加熱により発泡、あるいは化学的分解により発泡させて気泡を形成する方法、（２）ポリエステル樹脂の押出時にガスまたは気化可能物質を添加する方法、（３）ポリエステル樹脂に無機粒子および／または該樹脂と非相溶の熱可塑性樹脂（Ａ）を添加し、それを一軸または二軸延伸することにより微細な気泡を発生させる方法等が挙げられるが、本発明においては、製膜性、内部に含有せしめる気泡の量の調整し易さ、製造コストなどの総合的な点から、上記の（３）の方法を用いることが好ましい。上記の（３）の方法における無機粒子としては、シリカ、コロイダルシリカ、炭酸カルシウム、珪酸アルミ、リン酸カルシウム、アルミナ、炭酸マグネシウム、炭酸亜鉛、酸化チタン、酸化亜鉛（亜鉛華）、酸化アンチモン、酸化セリウム、酸化ジルコニウム、酸化錫、酸化ランタン、酸化マグネシウム、炭酸バリウム、塩基性炭酸鉛（鉛白）、硫酸バリウム、硫酸カルシウム、硫酸鉛、硫化亜鉛、マイカ、雲母チタン、タルク、クレー、カオリン、などの無機粒子が挙げられる。また、それらは単独もしくは２種類以上の混合で使用することが出来るが、中でも高い光学特性を製膜安定性が得られることから、硫酸バリウム粒子、二酸化チタン粒子が特に好ましい。無機粒子により気泡を含有させる場合、無機粒子は本発明の成形用白色ポリエステルフィルムの総重量に対して１～５０重量％含有されていることが好ましい。無機粒子が１重量％より少ない場合、比重を１．１以下にすることが困難となり、５０重量％より多い場合は、ポリエステル樹脂の機械強度、耐熱性、製造コストを損ねる場合があり好ましくない。
ポリエステル樹脂と非相溶な熱可塑性樹脂（Ａ）とは、ポリエチレン、ポリプロピレン、ポリブテン、ポリメチルペンテン、環状オレフィンのようなオレフィン系樹脂、スチレン系樹脂、ポリアクリレート樹脂、ポリカーボネート樹脂、ポリアクリロニトリル樹脂、ポリフェニレンスルフィド樹脂、フッ素系樹脂などが選ばれる。なかでも好ましいのはオレフィン系樹脂またはスチレン系樹脂であり、オレフィン系樹脂としてはポリエチレン、ポリプロピレン、ポリ４－メチルペンテン－１（以下、「ポリメチルペンテン」または「ＰＭＰ」と略称することがある）、エチレン－プロピレン共重合体、エチレン－ブテン－１共重合体、環状オレフィンが、スチレン系樹脂としてはポリスチレン、ポリメチルスチレン、ポリジメチルスチレンなどが好ましい。これらは単独重合体であっても共重合体であってもよく、さらには２種以上の熱可塑性樹脂（Ａ）を併用してもよい。熱可塑性樹脂（Ａ）は、本発明の成形用白色ポリエステルフィルムの総重量に対して１～５０重量％含有されていることが好ましい。熱可塑性樹脂（Ａ）が１重量％より少ない場合、比重を１．１以下にすることが困難となり、５０重量％より多い場合は、ポリエステル樹脂の機械強度、耐熱性、製造コストを損ねる場合があり好ましくない。比重を０．８～１．１とすることで、後に記載する反射率、貯蔵弾性率（Ｅ’）、成形後の荷重に対する形状保持性を好ましい範囲にすることができる。比重が１．１より大きい場合、気泡の形成が不十分であり、フィルムの反射率が低下する場合があり好ましくない。また、比重が０．８より小さい場合、成形後に荷重に対する形状保持性が低下する場合があり好ましくない。より好ましくは、比重が０．８２～１．０５であり、さらにこのましくは０．８５～１．０である。 The white polyester film for molding of the present invention needs to have a specific gravity of 0.8 to 1.1. As a method for setting the specific gravity in such a range, it is preferable to contain bubbles in the film. As a method of incorporating bubbles inside, (1) a method in which a foaming agent is contained in a polyester resin and foamed by heating during extrusion or film formation or foamed by chemical decomposition to form bubbles, (2) polyester (3) Adding inorganic particles and / or thermoplastic resin (A) incompatible with the resin to the polyester resin, and uniaxially or biaxially stretching it. In the present invention, from the comprehensive points such as film forming property, ease of adjusting the amount of bubbles contained inside, production cost, etc. It is preferable to use the method 3). As the inorganic particles in the method (3), silica, colloidal silica, calcium carbonate, aluminum silicate, calcium phosphate, alumina, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide (zinc white), antimony oxide, cerium oxide, Zirconium oxide, tin oxide, lanthanum oxide, magnesium oxide, barium carbonate, basic lead carbonate (lead white), barium sulfate, calcium sulfate, lead sulfate, zinc sulfide, mica, mica titanium, talc, clay, kaolin, etc. Particles. Further, they can be used alone or in combination of two or more. Among them, barium sulfate particles and titanium dioxide particles are particularly preferable because film formation stability can be obtained with high optical characteristics. When air bubbles are included in the inorganic particles, the inorganic particles are preferably contained in an amount of 1 to 50% by weight based on the total weight of the white polyester film for molding of the present invention. When the amount of inorganic particles is less than 1% by weight, it is difficult to make the specific gravity 1.1 or less. When the amount is more than 50% by weight, the mechanical strength, heat resistance and production cost of the polyester resin may be impaired, which is not preferable.
The thermoplastic resin incompatible with the polyester resin (A) is an olefin resin such as polyethylene, polypropylene, polybutene, polymethylpentene, or cyclic olefin, styrene resin, polyacrylate resin, polycarbonate resin, polyacrylonitrile resin, Polyphenylene sulfide resin, fluorine resin, etc. are selected. Of these, an olefin resin or a styrene resin is preferable. Examples of the olefin resin include polyethylene, polypropylene, and poly-4-methylpentene-1 (hereinafter, may be abbreviated as “polymethylpentene” or “PMP”). Ethylene-propylene copolymer, ethylene-butene-1 copolymer, and cyclic olefin, and polystyrene, polymethylstyrene, polydimethylstyrene and the like are preferable as the styrene resin. These may be a homopolymer or a copolymer, and two or more thermoplastic resins (A) may be used in combination. The thermoplastic resin (A) is preferably contained in an amount of 1 to 50% by weight based on the total weight of the white polyester film for molding of the present invention. When the thermoplastic resin (A) is less than 1% by weight, it is difficult to make the specific gravity 1.1 or less, and when it is more than 50% by weight, the mechanical strength, heat resistance and production cost of the polyester resin may be impaired. There is not preferable. By setting the specific gravity to 0.8 to 1.1, the reflectance, storage elastic modulus (E ′) described later, and shape retention with respect to the load after molding can be set within a preferable range. When the specific gravity is larger than 1.1, the formation of bubbles is insufficient, and the reflectance of the film may be lowered, which is not preferable. Moreover, when specific gravity is smaller than 0.8, the shape retainability with respect to a load may fall after shaping | molding, and it is unpreferable. More preferably, the specific gravity is 0.82 to 1.05, and more preferably 0.85 to 1.0.
　ポリエステル樹脂と熱可塑性樹脂（Ａ）の重量比を求める手法としては、それぞれの樹脂の種類に応じて、複数の分析を組み合わせる手法が考えられる。ポリエステル樹脂のみを溶媒で除去し、残った熱可塑性樹脂（Ａ）を遠心分離機にて分離し、得られる残留物の重量から重量比を求める方法、ＩＲ（赤外分光法）、１Ｈ－ＮＭＲや１３Ｃ－ＮＭＲによりそれぞれの樹脂を同定したのち、ポリエステル樹脂と熱可塑性樹脂（Ａ）がいずれも可溶な溶媒に溶解し、遠心分離により不純物や無機物を除去し、吸光度により濃度を求めることにより重量比を求める方法が使用できる。ポリエステル樹脂を可溶な溶媒としては、トリフルオロ酢酸や１，１，１，３，３，３－ヘキサフルオロー２－プロパノール、ｏ―クロロフェノールなどが用いられる。 As a technique for obtaining the weight ratio of the polyester resin and the thermoplastic resin (A), a technique in which a plurality of analyzes are combined depending on the type of each resin can be considered. A method in which only the polyester resin is removed with a solvent, and the remaining thermoplastic resin (A) is separated by a centrifuge, and the weight ratio is obtained from the weight of the resulting residue, IR (infrared spectroscopy), 1H-NMR After identifying each resin by 13C-NMR, the polyester resin and the thermoplastic resin (A) are both dissolved in a soluble solvent, impurities and inorganic substances are removed by centrifugation, and the concentration is determined by absorbance. A method for determining the weight ratio can be used. Examples of solvents that can dissolve the polyester resin include trifluoroacetic acid, 1,1,1,3,3,3-hexafluoro-2-propanol, o-chlorophenol, and the like.
　本発明の成形用白色ポリエステルフィルムは、表層のガラス転移温度（Ｔｇ）+６０℃における貯蔵弾性率（Ｅ’）が１０ＭＰａ以上３００ＭＰａ以下であることが好ましい。ある温度での貯蔵弾性率（Ｅ’）が小さければ、その温度において小さな力で変形しやすいことを示し、大きければ変形に大きな力が必要なことを示す。表層のガラス転移温度（Ｔｇ）+６０℃における貯蔵弾性率（Ｅ’）が１０ＭＰａより低い場合、フィルムの自重により垂れるなど自己支持性が低下する場合があり好ましくない。また、３００ＭＰａより大きければ、特定の形状を付与するための成形が困難になるため好ましくない。より好ましくは２０ＭＰａ以上２５０ＭＰａであり、さらに好ましくは５０ＭＰａ以上２００ＭＰａ以下である。表層のガラス転移温度（Ｔｇ）+６０℃における貯蔵弾性率（Ｅ’）をかかる範囲にする方法としては、特に限定されないが、上記のように表層のガラス転移温度を８０℃以上にする、比重を１．１以下にするなどの方法を組み合わせた上で、下記に記載の方法でフィルムを製造することで貯蔵弾性率を上記の範囲とすることができる。フィルムの内部に気泡を含有させる方法で比重を調整する場合、比重の増減に応じて貯蔵弾性率（Ｅ’）を調整することが可能である。気泡の含有によって見た目の断面積が大きくなり、貯蔵弾性率（Ｅ’）が低くなるためである。また、本発明で用いられるポリエステル樹脂として、共重合ポリエステル樹脂を使用しても良い。共重合ポリエステルは、一般的にホモポリマーと比較して結晶性が低下しやすいことが知られており、貯蔵弾性率（Ｅ’）を低くできる場合があり好ましい。共重合ポリエステルは、上記のポリエステル樹脂のジカルボン酸成分としてあげている中から２種以上、および／またはジオール成分としてあげている中から２種以上が共重合されていることが好ましい。特に、テレフタル酸と２，６－ナフタレンジカルボン酸の組み合わせ、エチレングリコールとスピログリコールの組み合わせは、ポリエチレンテレフタレートホモポリマーと比較して、ガラス転移温度を８０℃以上１２０℃以下としやすいため好ましい。共重合成分を導入する方法としては、原料であるポリエステルペレットの重合時に共重合成分を添加し、あらかじめ共重合成分が重合されたペレットとして用いても良いし、また、例えば、ポリエチレンナフタレートのように単独で重合されたペレットとポリエチレンテレフタレートペレットの混合物を押出し機に供給し、溶融時にエステル交換反応によって共重合化する方法を用いても良い。 The white polyester film for molding according to the present invention preferably has a storage elastic modulus (E ′) at a glass transition temperature (Tg) + 60 ° C. of the surface layer of 10 MPa or more and 300 MPa or less. If the storage elastic modulus (E ') at a certain temperature is small, it indicates that it is easy to deform with a small force at that temperature, and if it is large, it indicates that a large force is required for deformation. When the storage elastic modulus (E ′) at the glass transition temperature (Tg) + 60 ° C. of the surface layer is lower than 10 MPa, the self-supporting property may be lowered due to the film's own weight, which is not preferable. Moreover, since it will become difficult for the shaping | molding for providing a specific shape to be larger than 300 Mpa, it is unpreferable. More preferably, it is 20 MPa or more and 250 MPa, More preferably, it is 50 MPa or more and 200 MPa or less. Although it does not specifically limit as a method which makes the storage elastic modulus (E ') in 60 degreeC the glass transition temperature (Tg) of a surface layer in this range, Specific gravity which makes the glass transition temperature of a surface layer 80 degreeC or more as mentioned above The storage elastic modulus can be adjusted to the above-mentioned range by producing a film by the method described below after combining the methods such as setting the ratio to 1.1 or less. In the case where the specific gravity is adjusted by a method of incorporating bubbles in the film, it is possible to adjust the storage elastic modulus (E ′) according to the increase or decrease of the specific gravity. This is because the apparent cross-sectional area increases due to the inclusion of bubbles, and the storage elastic modulus (E ′) decreases. Moreover, you may use a copolyester resin as a polyester resin used by this invention. Copolyesters are generally known to have lower crystallinity than homopolymers, and are preferred because they may reduce the storage elastic modulus (E ′). It is preferable that two or more of the copolymer polyesters listed as the dicarboxylic acid component of the polyester resin and / or two or more of the copolymer polyesters listed as the diol component are copolymerized. In particular, a combination of terephthalic acid and 2,6-naphthalenedicarboxylic acid and a combination of ethylene glycol and spiroglycol are preferable because the glass transition temperature is easily set to 80 ° C. or higher and 120 ° C. or lower as compared with polyethylene terephthalate homopolymer. As a method for introducing a copolymer component, a copolymer component may be added at the time of polymerization of a raw material polyester pellet, and the copolymer component may be used as a pellet in which a copolymer component has been polymerized in advance. For example, polyethylene naphthalate is used. Alternatively, a method may be used in which a mixture of pellets independently polymerized and polyethylene terephthalate pellets is supplied to an extruder and copolymerized by transesterification at the time of melting.
　本発明の成形用白色ポリエステルフィルムの表層に使用されるポリエステル樹脂は、２種類以上のポリエステル樹脂を混合したものであっても構わない。２種類以上のポリエステル樹脂を混合すると、表層のガラス転移温度が二つ以上、測定される場合がある。その場合は、「表層のガラス転移温度+６０℃」の起点となるガラス転移温度は、最も温度が高いガラス転移温度とする。 The polyester resin used for the surface layer of the molding white polyester film of the present invention may be a mixture of two or more kinds of polyester resins. When two or more kinds of polyester resins are mixed, two or more glass transition temperatures of the surface layer may be measured. In this case, the glass transition temperature that is the starting point of “the glass transition temperature of the surface layer + 60 ° C.” is the glass transition temperature having the highest temperature.
　本発明の成形用白色ポリエステルフィルムは、芯層にボイド核剤を含有する気泡を有していることが好ましい。ここでいう芯層とは、三層以上のポリエステルフィルムにおいて、両表層を除くすべての層を指す。四層以上の場合は、芯層が二層以上存在する。芯層が二層以上ある場合は、少なくともいずれか一層にボイド核剤を含有する気泡を有していることが好ましい。ボイド核剤は成形用白色ポリエステルフィルムを構成する主たる樹脂成分と同一ではなく、かつ樹脂成分中に粒子状に分散し得るものであればよく、例えば無機微粒子、有機微粒子、各種熱可塑性樹脂、などが挙げられる。ボイド核剤を含有する気泡を得る方法は特に限定されないが、上記のポリエステル樹脂に無機粒子および／または該樹脂と非相溶の熱可塑性樹脂（Ａ）を添加し、それを一軸または二軸延伸することにより微細な気泡を発生させる方法等が好ましく用いられる。ボイド核剤を含有する気泡を有していることで、成形加工時にボイドがつぶれにくく、成形用白色ポリエステルフィルムを成形して白色樹脂成形体としたときに、反射率の低下、透過率の増大が起こりにくくなるため好ましい。 The white polyester film for molding of the present invention preferably has bubbles containing a void nucleating agent in the core layer. A core layer here refers to all the layers except the both surface layers in a polyester film of three or more layers. In the case of four or more layers, there are two or more core layers. When there are two or more core layers, it is preferable that at least any one layer has bubbles containing a void nucleating agent. The void nucleating agent is not the same as the main resin component constituting the white polyester film for molding, and may be any material that can be dispersed in the resin component, for example, inorganic fine particles, organic fine particles, various thermoplastic resins, etc. Is mentioned. The method for obtaining bubbles containing a void nucleating agent is not particularly limited, but inorganic particles and / or a thermoplastic resin (A) incompatible with the resin is added to the polyester resin, and the resultant is uniaxially or biaxially stretched. A method of generating fine bubbles by doing so is preferably used. Due to having voids containing void nucleating agent, voids are not easily crushed during molding, and when white polyester film for molding is molded into a white resin molded body, the reflectance decreases and the transmittance increases. Is preferable because it is difficult to occur.
　本発明の成形用白色ポリエステルフィルムは、反射率９８％以上かつ透過率３％未満であることが好ましい。ここでいう反射率とは、光の波長領域４００～７００ｎｍにおける平均反射率とし、透過率は、可視光領域の波長（４００～８００ｎｍ）の光を用いて、ＪＩＳ－Ｋ－７３６１－１に準拠して測定した光の透過率のことである。全光線透過率という場合もある。反射率が９８％未満あるいは透過率が３％以上となる場合、直下型バックライトに組み込んだ際に十分な輝度が出ない場合があり好ましくない。反射率および透過率を上記の範囲とする方法としては、特に限定されないが、ポリエステル樹脂に無機粒子および／または該樹脂と非相溶の熱可塑性樹脂（Ａ）を添加し、それを一軸または二軸延伸することにより微細な気泡を発生させる方法が好ましく用いられる。 The white polyester film for molding of the present invention preferably has a reflectance of 98% or more and a transmittance of less than 3%. The reflectance here refers to the average reflectance in the wavelength region of 400 to 700 nm of light, and the transmittance conforms to JIS-K-7361-1 using light in the wavelength of visible light region (400 to 800 nm). It is the transmittance of light measured in this way. Sometimes referred to as total light transmittance. When the reflectance is less than 98% or the transmittance is 3% or more, sufficient luminance may not be obtained when it is incorporated in a direct type backlight, which is not preferable. A method for setting the reflectance and transmittance within the above ranges is not particularly limited, but inorganic particles and / or a thermoplastic resin (A) incompatible with the resin is added to the polyester resin, and the resultant is uniaxially or biaxially. A method of generating fine bubbles by axial stretching is preferably used.
　本発明の成形用白色ポリエステルフィルムは、製膜性、成形性の観点および反射・透過率、成形後の荷重に対する形状保持性を好ましい範囲にするために、フィルム厚みは１００～５００μｍであることが好ましく、１２５～４００μｍであればより好ましく、１６０～３５０μｍであることがさらに好ましい。 The white polyester film for molding of the present invention has a film thickness of 100 to 500 μm in order to make the film forming property, moldability viewpoint, reflection / transmittance, and shape retention with respect to the load after molding into a preferable range. Preferably, it is 125 to 400 μm, more preferably 160 to 350 μm.
　次に本発明の成形用白色ポリエステルフィルムの製造方法について、その一例を説明するが特に限定されるものではない。少なくとも２台の一軸または二軸押出機、主押出機と副押出機を有する複合製膜装置において、主押出機に芯層（Ｙ）の原料となる樹脂、副押出機に表層（Ｘ）の原料となる樹脂を投入する。それぞれの原料は水分率が５０ｐｐｍ以下となるように乾燥されていることが好ましい。このようにして各押出機に原料を供給し、例えば２台の押出機とＴダイ上部に設置したフィードブロックやマルチマニホールドにてＸ／Ｙ／Ｘの３層積層フィルムとすることができる。押出された未延伸シートは、冷却されたドラム上で密着冷却固化し、未延伸積層フィルムを得る。このとき、均一なフィルムを得るために静電気を印加してドラム上に密着させることが望ましい。その後、必要により延伸工程、熱処理工程を経て目的のポリエステルフィルムを得る。 Next, an example of the method for producing a white polyester film for molding according to the present invention will be described, but it is not particularly limited. In a composite film forming apparatus having at least two single-screw or twin-screw extruders, a main extruder and a sub-extruder, the main extruder has a resin as a raw material for the core layer (Y), and the sub-extruder has a surface layer (X). Input the raw material resin. Each raw material is preferably dried so that the moisture content is 50 ppm or less. In this way, the raw materials are supplied to each extruder and, for example, a three-layer laminated film of X / Y / X can be formed by using two extruders and a feed block or a multi-manifold installed on the top of the T die. The extruded unstretched sheet is closely cooled and solidified on a cooled drum to obtain an unstretched laminated film. At this time, in order to obtain a uniform film, it is desirable to apply static electricity and make it adhere on the drum. Thereafter, if necessary, a target polyester film is obtained through a stretching step and a heat treatment step.
　この未延伸フィルムをロール加熱、必要に応じて赤外線加熱等でポリマーのガラス転移温度（Ｔｇ）以上に加熱し、長手方向（以降、縦方向と呼ぶ）に延伸して縦延伸フィルムを得る。この延伸は２個以上のロールの周速差を利用して行う。縦延伸の倍率は用途の要求特性にもよるが、好ましくは２～６倍、より好ましくは３～４倍である。２倍未満とすると反射率が低い場合があり、６倍を超えると製膜中に破断が発生し易くなる場合がある。縦延伸後のフィルムは、続いて、縦方向と直交する方向（以降、横方向と呼ぶ）に延伸、熱固定、熱弛緩の処理を順次施して二軸配向フィルムとするが、これら処理はフィルムを走行させながら行う。このとき、横延伸のための予熱および延伸温度はポリマーのガラス転移温度（Ｔｇ）以上（Ｔｇ＋２０℃）で行うのが好ましい。横延伸の倍率は、用途の要求特性にもよるが、好ましくは２．５～６倍、より好ましくは３～４倍である。２．５倍未満であると反射率が低い場合がある。６倍を超えると製膜中に破断が発生し易くなる場合がある。得られた二軸延伸積層フィルムの結晶配向を完了させて、平面性と寸法安定性を付与するために、引き続きテンター内にて１８０～２３０℃の温度で１～６０秒間の熱処理を行ない、均一に徐冷後、室温まで冷却し、ロールに巻き取る。なお、かかる熱処理はフィルムをその長手方向および／または幅方向に弛緩させつつ行ってもよい。 This unstretched film is heated to a temperature higher than the glass transition temperature (Tg) of the polymer by roll heating or infrared heating as necessary, and stretched in the longitudinal direction (hereinafter referred to as the longitudinal direction) to obtain a longitudinally stretched film. This stretching is performed by utilizing the difference in peripheral speed between two or more rolls. The longitudinal stretch ratio is preferably 2 to 6 times, more preferably 3 to 4 times, although it depends on the required properties of the application. If it is less than 2 times, the reflectance may be low, and if it exceeds 6 times, breakage may easily occur during film formation. The film after longitudinal stretching is then subjected to stretching, heat setting, and thermal relaxation in the direction perpendicular to the longitudinal direction (hereinafter referred to as the transverse direction) to form a biaxially oriented film. While running. At this time, preheating and stretching temperature for transverse stretching are preferably performed at a glass transition temperature (Tg) or higher (Tg + 20 ° C.) of the polymer. The transverse stretching ratio is preferably 2.5 to 6 times, more preferably 3 to 4 times, although it depends on the required characteristics of the application. If it is less than 2.5 times, the reflectance may be low. If it exceeds 6 times, breakage may easily occur during film formation. In order to complete the crystal orientation of the obtained biaxially stretched laminated film and to impart flatness and dimensional stability, it is then subjected to heat treatment at a temperature of 180 to 230 ° C. for 1 to 60 seconds in a tenter, and uniform After cooling slowly, it is cooled to room temperature and wound on a roll. The heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction.
　またここでは逐次二軸延伸法によって延伸する場合を例に詳細に説明したが、本発明のポリエステルフィルムは逐次二軸延伸法、同時二軸延伸法のいずれの方法で延伸してもよく、さらに必要に応じて、二軸延伸後、再縦延伸および／または再横延伸を行ってもよい。 In addition, the case where the film is stretched by the sequential biaxial stretching method has been described in detail here, but the polyester film of the present invention may be stretched by any of the sequential biaxial stretching method and the simultaneous biaxial stretching method. If necessary, after the biaxial stretching, re-longitudinal stretching and / or re-lateral stretching may be performed.
　こうして得られた二軸延伸積層フィルムに平面安定性、寸法安定性を付与するため、引き続いてテンター内で熱処理（熱固定）を行い、均一に徐冷後、室温付近まで冷却した後、巻き取ることにより、本発明の白色フィルムを得ることができる。 In order to impart planar stability and dimensional stability to the biaxially stretched laminated film thus obtained, heat treatment (heat setting) is subsequently performed in the tenter, and after uniform cooling, cooling to near room temperature and winding up By this, the white film of the present invention can be obtained.
　また、本発明の効果が損なわれない範囲で、樹脂層（Ａ）の少なくとも片面に、易滑性や帯電防止性、紫外光吸収性能等を付与するために、周知の技術を用いて種々の塗液を塗布したり、耐衝撃性を高めるためにハードコート層などを設けても良い。塗布は、フィルム製造時に塗布（インラインコーティング）してもよいし、フィルム製造後の白色フィルム上に塗布（オフラインコーティング）してもよい。 In addition, various kinds of techniques can be used by using a well-known technique in order to impart slipperiness, antistatic property, ultraviolet light absorption performance, etc. to at least one surface of the resin layer (A) as long as the effects of the present invention are not impaired. A hard coat layer or the like may be provided in order to apply a coating liquid or improve impact resistance. The coating may be performed at the time of film production (in-line coating), or may be performed on a white film after film production (off-line coating).
　また、本発明は上記に記載の成形用白色ポリエステルフィルムを成形した白色樹脂成形体であってもよい。成形方法としては特に限定されないが、真空成形、圧空成形、真空圧空成形、プレス成形、プラグアシスト真空圧空成形のようにフィルムのみを成形する方法、インサート成形、ＴＯＭ（Ｔｈｒｅｅ　ｄｉｍｅｎｓｉｏｎ　Ｏｖｅｒｌａｙ　Ｍｅｔｈｏｄ）成形、三次元ラミネート成形などのように基材がある成形方法など、一般に公知の成形方法で成形できる。例えば、真空圧空成形を行う場合は、４００℃の遠赤外線ヒーターで、フィルム表面温度がＴｇ＋５０℃以上の温度になるようにフィルムを加熱し、５０℃に加熱した金型に沿って真空圧空成形（圧力：１ＭＰａ）を行うことで、本発明の反射板が得られる。本発明の成形体の形状は特に限定されるものではないが、一つもしくは以上の凹みを形成していることが好ましい。凹みの形状としては、錐台状、半球状、球冠状、柱状、これらの組み合わせ、中間形状、楕円ように歪ませた形状、角にＲがついて丸みを帯びた形状であってもよい。中でも四角錐台形状、六角錐台形状であれば、面を同一形状で埋めやすく後述する用途として使いやすく好ましい。 Further, the present invention may be a white resin molded body obtained by molding the white polyester film for molding described above. The forming method is not particularly limited, but a method of forming only a film, such as vacuum forming, pressure forming, vacuum pressure forming, press forming, plug assist vacuum pressure forming, insert molding, TOM (Three dimension Overlay Method) forming, tertiary It can be formed by a generally known forming method such as a forming method with a base material such as original laminate forming. For example, when vacuum / pressure forming is performed, the film is heated with a far-infrared heater at 400 ° C. so that the film surface temperature becomes Tg + 50 ° C. or higher, and vacuum / pressure forming is performed along a mold heated to 50 ° C. ( By performing the pressure of 1 MPa, the reflector of the present invention is obtained. The shape of the molded body of the present invention is not particularly limited, but it is preferable that one or more dents are formed. The shape of the dent may be a frustum shape, a hemispherical shape, a spherical crown shape, a columnar shape, a combination thereof, an intermediate shape, a shape that is distorted like an ellipse, or a rounded shape with an R at a corner. In particular, a quadrangular frustum shape or a hexagonal frustum shape is preferable because it is easy to fill the surface with the same shape and is easy to use for the use described later.
　本発明の白色樹脂成形体は、ＬＥＤ照明ユニット用の反射板として好適に用いることができる。本発明の白色樹脂成形体を使用したＬＥＤ照明ユニットの場合、隣り合うＬＥＤの光漏れが起こりにくく部分駆動機能を搭載する照明用途として好ましい。特に平面型ＬＥＤ照明ユニット用の反射板として好ましい。 The white resin molded product of the present invention can be suitably used as a reflector for an LED lighting unit. In the case of an LED lighting unit using the white resin molded body of the present invention, light leakage of adjacent LEDs hardly occurs, which is preferable as an illumination application equipped with a partial drive function. It is particularly preferable as a reflector for a flat LED lighting unit.
　本発明の白色樹脂成形体は、直下型ＬＥＤバックライトユニット用の反射板として好適に用いることができる。本発明の反射板を使用した直下型ＬＥＤバックライトユニットの場合、隣り合うＬＥＤの光漏れが起こりにくくローカルディミング機能を搭載したバックライトに好ましい。特に液晶ディスプレイ、液晶テレビ、液晶モニターなどに使用される直下型ＬＥＤバックライトユニット用の反射板として好ましい。 The white resin molded product of the present invention can be suitably used as a reflector for a direct type LED backlight unit. In the case of a direct type LED backlight unit using the reflector of the present invention, light leakage of adjacent LEDs hardly occurs, which is preferable for a backlight equipped with a local dimming function. Particularly, it is preferable as a reflector for a direct type LED backlight unit used for a liquid crystal display, a liquid crystal television, a liquid crystal monitor, and the like.
　以下、実施例により本発明を詳述する。なお、各特性値は以下の方法で測定した。 Hereinafter, the present invention will be described in detail by way of examples. Each characteristic value was measured by the following method.
　（１）ガラス転移温度
示差走査熱量計（セイコー電子工業製、ＲＤＣ２２０）を用い、ＪＩＳ　Ｋ７１２１－１９８７、ＪＩＳ　Ｋ７１２２－１９８７に準拠して測定および、解析を行った。ポリエステル層もしくはポリエステルフィルムを５ｍｇ、サンプルに用い、２５℃から２０℃／分で３００℃まで昇温した際のＤＳＣ曲線より得られた、ガラス状態からゴム状態への転移に基づく比熱変化を読み取り、各ベースラインの延長した直線から縦軸（熱流を示す軸）方向に等距離にある直線と、ガラス転移の階段状変化部分の曲線とが交わる点の中間点ガラス転移温度を求め、ガラス転移温度とした。なお、ベースライン上に見られる、極微小なピーク面積（結晶融解エネルギー換算で０．５Ｊ／ｇ以下）の吸熱ピークについてはノイズとして除去した。表層のみを測定する場合は、カッターで表層を削りとって測定を行った。 (1) Using a glass transition temperature differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., RDC220), measurement and analysis were performed in accordance with JIS K7121-1987 and JIS K7122-1987. Read the specific heat change based on the transition from the glass state to the rubber state, obtained from the DSC curve when the polyester layer or polyester film was used as a sample, and the temperature was raised from 25 ° C. to 300 ° C. at 20 ° C./min. Determine the glass transition temperature at the midpoint of the point where the straight line equidistant from the extended straight line of each baseline in the direction of the vertical axis (the axis indicating the heat flow) and the curve of the stepwise change part of the glass transition intersect. It was. Note that an endothermic peak with a very small peak area (0.5 J / g or less in terms of crystal melting energy) seen on the baseline was removed as noise. When measuring only the surface layer, the surface layer was shaved with a cutter.
　（２）貯蔵弾性率（Ｅ‘）
フィルムを長手方向および幅方向に長さ６０ｍｍ×幅５ｍｍの矩形に切り出しサンプルとした。動的粘弾性測定装置（セイコーインスツルメンツ製、ＤＭＳ６１００）を用い、下記の条件下で、フィルム表層のＴｇ＋５０℃での弾性率（Ｅ‘）を求めた。
周波数：１Ｈｚ、試長：２０ｍｍ、最小荷重：約１００ｍＮ、振幅：１０μm、   
測定温度範囲：２０℃～２３０℃、昇温速度：５℃／分。 (2) Storage elastic modulus (E ')
The film was cut into a rectangular shape with a length of 60 mm and a width of 5 mm in the longitudinal direction and the width direction as a sample. Using a dynamic viscoelasticity measuring apparatus (Seiko Instruments, DMS6100), the elastic modulus (E ′) at Tg + 50 ° C. of the film surface layer was determined under the following conditions.
Frequency: 1 Hz, test length: 20 mm, minimum load: about 100 mN, amplitude: 10 μm,
Measurement temperature range: 20 ° C. to 230 ° C., heating rate: 5 ° C./min.
　（３）比重
　フィルムから１辺が５ｃｍである正方形サンプルを５枚切りだし、それぞれＪＩＳ　Ｋ７１１２－１９８０に基づいて電子比重計ＳＤ－１２０Ｌ（ミラージュ貿易（株）製）を用いて測定した。得られた計５点の測定値の相加平均を求め、当該フィルムの比重とした。 (3) Specific gravity Five square samples each having a side of 5 cm were cut out from the film and measured using an electronic hydrometer SD-120L (manufactured by Mirage Trade Co., Ltd.) based on JIS K7112-1980. The arithmetic average of the obtained measurement values of a total of 5 points was calculated | required and it was set as the specific gravity of the said film.
　（４）反射率
　日立ハイテクノロジーズ製分光光度計（Ｕ―３３１０）に６０ｍｍφ積分球を取り付け、酸化アルミニウムの標準白色板（日立ハイテクノロジーズ製、部品Ｎｏ．２１０－０７４０）を１００％としたときの反射率を４００～７００ｎｍにわたって測定する。得られたチャートより５ｎｍ間隔で反射率を読み取り、算術平均値を計算し、反射率とする。 (4) Reflectivity When a spectrophotometer (U-3310) manufactured by Hitachi High-Technologies is attached with a 60 mmφ integrating sphere, and a standard white plate of aluminum oxide (Part No. 210-0740 manufactured by Hitachi High-Technologies) is taken as 100%. The reflectivity is measured over 400-700 nm. The reflectance is read at intervals of 5 nm from the obtained chart, and the arithmetic average value is calculated to obtain the reflectance.
　（５）透過率（全光線透過率）
日本電色工業（株）製濁度計「ＮＤＨ５０００」を用いて、全光線透過率の測定はＪＩＳ「プラスチック透明材料の全光線透過率の試験方法」（Ｋ７３６１－１、１９９７年版）に従って測定した。 (5) Transmittance (total light transmittance)
Using a turbidimeter “NDH5000” manufactured by Nippon Denshoku Industries Co., Ltd., the total light transmittance was measured according to JIS “Testing method of total light transmittance of plastic transparent material” (K7361-1, 1997 edition). .
　（６）成形性
　浅野研究所製成形機（ＦＫＳ－０６３１－２０）を用いて４００℃の遠赤外線ヒーターで、フィルム表面温度がＴｇ＋５０℃以上の温度になるようにフィルムを加熱し、５０℃に加熱した金型（底面直径５０ｍｍ、円筒形状）に沿って真空圧空成形（圧力：１ＭＰａ）を行った。金型に沿って成形できた状態を成形度合い（絞り比：成形高さ／底面直径）を用いて以下の基準で評価した。 
◎：絞り比０．７以上で成形できた。   
○：絞り比０．７～０．４で成形できた。  
△：絞り比０．４～０．１で成形できた。 
×：破れが発生し、絞り比０．１で成形できなかった。もしくは、追従性が低く、成形できなかった。 
△以上を合格とした。 (6) Formability Using a molding machine manufactured by Asano Laboratories (FKS-0631-20), heat the film with a far-infrared heater at 400 ° C. so that the film surface temperature is Tg + 50 ° C. or higher. Vacuum / pressure forming (pressure: 1 MPa) was performed along the heated mold (bottom diameter: 50 mm, cylindrical shape). The state of being molded along the mold was evaluated according to the following criteria using the molding degree (drawing ratio: molding height / bottom diameter).
A: Molding was possible with a drawing ratio of 0.7 or more.
○: Molding was possible with a drawing ratio of 0.7 to 0.4.
Δ: Molding was possible with a drawing ratio of 0.4 to 0.1.
X: Breakage occurred and molding could not be performed with a drawing ratio of 0.1. Alternatively, the followability was low and molding was not possible.
△ or more was accepted.
　（７）形状保持性（耐荷重）
　浅野研究所製成形機（ＦＫＳ－０６３１－２０）を用いて４００℃の遠赤外線ヒーターで、フィルム表面温度がＴｇ＋５０℃以上の温度になるようにフィルムを加熱し、５０℃に加熱した金型（底面直径５０ｍｍ、高さ２５ｍｍ、円錐形状）に沿って真空圧空成形（圧力：１ＭＰａ）を行った。成形された円錐体を強伸度測定装置（株式会社ボールドウィン社製、ＲＴＦ－１２１０）と圧縮試験冶具を用いて圧縮試験を行った。得られたＳ－Ｓカーブから弾性変形と塑性変形の境界（図１）を読み取り、その試験力（Ｎ）から耐荷重性を評価した
◎：試験力　１５Ｎ以上
○：試験力　１０Ｎ以上１５Ｎ未満
△：試験力　５Ｎ以上１０Ｎ未満
×：試験力　５Ｎ未満
△以上を合格とした。 (7) Shape retention (withstand load)
Using a molding machine manufactured by Asano Laboratories (FKS-0631-20), a far-infrared heater at 400 ° C. was used to heat the film so that the film surface temperature was Tg + 50 ° C. or higher, and a mold heated to 50 ° C. ( Vacuum / pressure forming (pressure: 1 MPa) was performed along a bottom diameter of 50 mm, a height of 25 mm, and a conical shape. The molded cone was subjected to a compression test using a high elongation measuring device (RTF-1210, manufactured by Baldwin Co., Ltd.) and a compression test jig. The boundary between elastic deformation and plastic deformation (Fig. 1) was read from the obtained SS curve, and load resistance was evaluated from the test force (N). ◎: Test force 15N or more ○: Test force 10N or more and less than 15N △ : Test force 5N or more and less than 10N x: Test force Less than 5N Δ or more was regarded as acceptable.
　（８）形状保持性（耐熱）
　浅野研究所製成形機（ＦＫＳ－０６３１－２０）を用いて４００℃の遠赤外線ヒーターで、フィルム表面温度がＴｇ＋６０℃以上の温度になるようにフィルムを加熱し、５０℃に加熱した金型（底面直径５０ｍｍ、高さ２５ｍｍ、円錐形状）に沿って真空圧空成形（圧力：１ＭＰａ）を行った。成形された円錐体を８０℃のオーブンに３０分投入し、加熱前後の高さの変化率を測定した。高さの測定には、ワンショット３Ｄ形状測定機ＶＲ－３２００（(株)キーエンス社製）を用いた。
◎：変化率　３％未満
○：変化率　３％以上　５%未満
△：変化率　５％以上　８％未満
×：変化率　８％以上
△以上を合格とした。 (8) Shape retention (heat resistance)
Using a molding machine manufactured by Asano Laboratories (FKS-0631-20), a far-infrared heater at 400 ° C. was used to heat the film so that the film surface temperature was Tg + 60 ° C. or higher, and a mold heated to 50 ° C. ( Vacuum / pressure forming (pressure: 1 MPa) was performed along a bottom diameter of 50 mm, a height of 25 mm, and a conical shape. The formed cone was placed in an oven at 80 ° C. for 30 minutes, and the rate of change in height before and after heating was measured. For the height measurement, a one-shot 3D shape measuring machine VR-3200 (manufactured by Keyence Corporation) was used.
◎: Change rate of less than 3% ○: Change rate of 3% or more and less than 5% Δ: Change rate of 5% or more and less than 8% ×: Change rate of 8% or more and Δ or more was regarded as acceptable.
　（９）光学ムラ
　浅野研究所製成形機（ＦＫＳ－０６３１－２０）を用いて４００℃の遠赤外線ヒーターで、フィルム表面温度がＴｇ＋６０℃以上の温度になるようにフィルムを加熱し、５０℃に加熱した金型（１辺５０ｍｍの２×２マス、高さ１０ｍｍ、厚さ１０ｍｍの壁を有する箱型）に沿って真空圧空成形（圧力：１ＭＰａ）を行った。各マスの底に直径１２ｍｍの穴を開け、穴からＬＥＤとレンズキャップが出るように市販テレビ（ハイアール社製、ＬＥ４２Ａ７０００）のバックライトに組み込み、光学フィルム群を乗せてＬＥＤを点灯させて見た目を観察した。
◎：箱の四隅まで明るく見える
○：明るく見える
×：暗く見える
　［使用原料］
　（１）ポリエステル樹脂（ａ）
　テレフタル酸およびエチレングリコールから、三酸化アンチモンを触媒として、常法により重合を行い、ポリエチレンテレフタレート（ＰＥＴ）を得た。得られたＰＥＴのガラス転移温度は７７℃、融点は２５５℃、固有粘度は０．６３ｄｌ／ｇ、末端カルボキシル基濃度は４０ｅｑ．／ｔであった。 (9) Optical unevenness Using a molding machine manufactured by Asano Laboratories (FKS-0631-20), heat the film with a far-infrared heater at 400 ° C. so that the film surface temperature is Tg + 60 ° C. or higher. Vacuum / pressure forming (pressure: 1 MPa) was performed along a heated mold (a box shape having a wall of 2 × 2 mass with a side of 50 mm, a height of 10 mm, and a thickness of 10 mm). A hole with a diameter of 12 mm is made in the bottom of each square, and the LED and the lens cap are inserted into the backlight of a commercial television (made by Haier, LE42A7000), and the optical film group is put on and the LED is turned on. Observed.
◎: Looks bright up to the four corners of the box ○: Looks bright ×: Looks dark [Raw materials]
(1) Polyester resin (a)
Polymerization was carried out from terephthalic acid and ethylene glycol by a conventional method using antimony trioxide as a catalyst to obtain polyethylene terephthalate (PET). The obtained PET has a glass transition temperature of 77 ° C., a melting point of 255 ° C., an intrinsic viscosity of 0.63 dl / g, and a terminal carboxyl group concentration of 40 eq. / T.
　（２）ポリエステル樹脂（ｂ）
　２，６－ナフタレンジカルボン酸ジメチルおよびエチレングリコールから、酢酸マンガンを触媒として、エステル交換反応を実施した。エステル交換反応終了後、三酸化アンチモンを触媒として常法によりポリエチレンナフタレート（ＰＥＮ）を得た。得られたＰＥＮのガラス転移温度は１２４℃、融点は２６５℃、固有粘度は０．６２ｄｌ／ｇ、末端カルボキシル基濃度は２５ｅｑ．／ｔであった。 (2) Polyester resin (b)
A transesterification reaction was carried out from dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol using manganese acetate as a catalyst. After the transesterification reaction, polyethylene naphthalate (PEN) was obtained by a conventional method using antimony trioxide as a catalyst. The obtained PEN had a glass transition temperature of 124 ° C., a melting point of 265 ° C., an intrinsic viscosity of 0.62 dl / g, and a terminal carboxyl group concentration of 25 eq. / T.
　（３）共重合ポリエステル樹脂（ｃ）
　市販の１，４－シクロヘキサンジメタノール共重合ポリエステル（イーストマン・ケミカル社製 ＧＮ００１）を使用した。ガラス転移温度は８５℃、固有粘度は０．７５ｄｌ／ｇであった。 (3) Copolyester resin (c)
A commercially available 1,4-cyclohexanedimethanol copolymerized polyester (GN001 manufactured by Eastman Chemical Co.) was used. The glass transition temperature was 85 ° C. and the intrinsic viscosity was 0.75 dl / g.
　（４）共重合ポリエステル樹脂（ｄ）
　ジカルボン酸成分としてテレフタル酸成分が８２．５モル％、イソフタル酸成分が１７．５モル％、グリコール成分としてエチレングリコール成分が１００モル％であるイソフタル酸共重合ポリエチレンテレフタレート樹脂を使用した。ガラス転移温度は７０℃、固有粘度は０．７ｄｌ／ｇであった。
（５）共重合ポリエステル樹脂（ｅ）
　ジカルボン酸成分としてテレフタル酸成分が１００モル％、グリコール成分としてエチレングリコール成分が７０モル％、ネオペンチルグリコール成分が３０モル％であるネオペンチルグリコール共重合ポリエチレンテレフタレート樹脂を使用した。固有粘度は０．７５ｄｌ／ｇであった。 (4) Copolyester resin (d)
An isophthalic acid copolymerized polyethylene terephthalate resin containing 82.5 mol% of a terephthalic acid component as a dicarboxylic acid component, 17.5 mol% of an isophthalic acid component, and 100 mol% of an ethylene glycol component as a glycol component was used. The glass transition temperature was 70 ° C. and the intrinsic viscosity was 0.7 dl / g.
(5) Copolyester resin (e)
A neopentyl glycol copolymer polyethylene terephthalate resin having a terephthalic acid component of 100 mol% as a dicarboxylic acid component, an ethylene glycol component of 70 mol% and a neopentyl glycol component of 30 mol% as a glycol component was used. The intrinsic viscosity was 0.75 dl / g.
　（６）ポリエステル樹脂（ｆ）
　市販のポリブチレンテレフタレート樹脂、東レ（株）社製“トレコン”（登録商標）１２００Ｓを用いた。融点は２２４℃、固有粘度は１．２６ｄｌ／ｇであった。 (6) Polyester resin (f)
A commercially available polybutylene terephthalate resin, “Toraycon” (registered trademark) 1200S manufactured by Toray Industries, Inc. was used. The melting point was 224 ° C. and the intrinsic viscosity was 1.26 dl / g.
　（７）共重合ポリエステル樹脂（ｇ）
　市販のスピログリコール共重合ポリエステル樹脂、三菱ガス化学（株）社製“アルテスター”（登録商標）Ｓ２０００を用いた。ガラス転移温度は９５℃、固有粘度は０．７５ｄｌ／ｇであった。 (7) Copolyester resin (g)
A commercially available spiroglycol copolymer polyester resin, “Altester” (registered trademark) S2000 manufactured by Mitsubishi Gas Chemical Company, Inc. was used. The glass transition temperature was 95 ° C. and the intrinsic viscosity was 0.75 dl / g.
　（８）共重合ポリエステル樹脂（ｈ）
　市販のイソフタル酸共重合ポリシクロヘキサンジメチレンテレフタレート（Ｅａｓｔｍａｎ　ＣＨＥＭＩＣＡＬ社製「Ｅａｓｔａｒ ＡＮ００４」）を使用した。ガラス転移温度８３℃、固有粘度０．７５ｄｌ／ｇであった。 (8) Copolyester resin (h)
Commercially available isophthalic acid copolymerized polycyclohexanedimethylene terephthalate (Eastman CHEMICAL "Eastar AN004") was used. The glass transition temperature was 83 ° C. and the intrinsic viscosity was 0.75 dl / g.
　（９）二酸化チタンマスター（ｉ）
ポリエステル樹脂（ａ）を５０重量部と二酸化チタン粒子（数平均粒径０．５μｍ）５０重量部を二軸押出機にて混練し、二酸化チタンマスターペレット（ｋ）を得た。
（１０）熱可塑性樹脂（ｊ）
　市販のポリメチルペンテン原料「ＴＰＸ　ＲＴ１８」（三井化学株式会社、融点２３３℃）
（１１）環状オレフィン樹脂（ｋ）
　市販の環状オレフィン樹脂「ＴＯＰＡＳ ６０１７」（日本ポリプラスチックス株式会社）を用いた。 (9) Titanium dioxide master (i)
50 parts by weight of polyester resin (a) and 50 parts by weight of titanium dioxide particles (number average particle size 0.5 μm) were kneaded with a twin screw extruder to obtain titanium dioxide master pellets (k).
(10) Thermoplastic resin (j)
Commercially available polymethylpentene raw material “TPX RT18” (Mitsui Chemicals, Inc., melting point 233 ° C.)
(11) Cyclic olefin resin (k)
A commercially available cyclic olefin resin “TOPAS 6017” (Nippon Polyplastics Co., Ltd.) was used.
　（１２）共重合ポリエステル（ｌ）
　市販のイソソルビドおよび１，４－シクロヘキサンジメタノール共重合ポリエステル樹脂（ＳＫ Ｃｈｅｍｉｃａｌｓ社製「ＥＣＯＺＥＮ ＢＳ３００」）を使用した。 (12) Copolyester (l)
Commercially available isosorbide and 1,4-cyclohexanedimethanol copolymerized polyester resin (“ECOZEN BS300” manufactured by SK Chemicals) were used.
　（１３）共重合ポリエステル（ｍ）
　　ジカルボン酸成分として２，６－ナフタレンジカルボン酸成分が１００モル％、グリコール成分としてエチレングリコール成分が８５モル％、ネオペンチルグリコール成分が１５モル％であるネオペンチルグリコール共重合ポリエチレンテレフタレート樹脂を使用した。ガラス転移温度は１１２℃、固有粘度は０．７０ｄｌ／ｇであった。 (13) Copolyester (m)
A neopentyl glycol copolymer polyethylene terephthalate resin containing 100 mol% of 2,6-naphthalenedicarboxylic acid component as dicarboxylic acid component, 85 mol% of ethylene glycol component and 15 mol% of neopentyl glycol component as glycol component was used. The glass transition temperature was 112 ° C. and the intrinsic viscosity was 0.70 dl / g.
　（実施例１，３～７、９）
表１示した組成の原料を１８０℃の温度で６時間真空乾燥した後に主押出機に芯層（Ｙ）の原料を供給し２８０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行い、副押出機に表層（Ｘ）の原料を供給し２９０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行った後に、Ｔダイ複合口金内で、表層（Ｘ）が芯層（Ｙ）の両表層に積層（Ｘ／Ｙ／Ｘ）されるよう合流せしめた。 (Examples 1, 3 to 7, 9)
After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material for the core layer (Y) was supplied to the main extruder, melt-extruded at a temperature of 280 ° C., and filtered through a 30 μm cut filter. The raw material of the surface layer (X) is supplied to the extruder, melt-extruded at a temperature of 290 ° C., filtered through a 30 μm cut filter, and then the surface layer (X) is the both surface layers of the core layer (Y) in the T-die composite die. To be laminated (X / Y / X).
　次いで、シート状に押出して溶融シートとし、該溶融シートを、表面温度２５℃に保たれたドラム上に静電印加法で密着冷却固化させて未延伸フィルムを得た。続いて、該未延伸フィルムを８０℃の温度に加熱したロール群で予熱した後、赤外線ヒーターで両面から照射しながら、長手方向（縦方向）に表２の倍率にて延伸を行い、２５℃の温度のロール群で冷却して一軸延伸フィルムを得た。その後、一軸延伸フィルムの両端をクリップで把持しながらテンター内の１１０℃の予熱ゾーンに導き、引き続き１２０ ℃ で長手方向に垂直な方向（横方向）に表２の倍率にて延伸した。さらに引き続いて、テンター内の熱処理ゾーンで表２の温度の熱処理を施し、次いで均一に徐冷後、ロールに巻き取り、表２に記載の厚みの成形用白色ポリエステルフィルムを得た。 Next, the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film. Subsequently, the unstretched film was preheated with a roll group heated to a temperature of 80 ° C., and then stretched at a magnification in Table 2 in the longitudinal direction (longitudinal direction) while being irradiated from both sides with an infrared heater, and 25 ° C. A uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C. preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C. Subsequently, heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
　（実施例２、８、１１～２０）
表１に示した組成の原料を１８０℃の温度で６時間真空乾燥した後に主押出機に芯層（Ｙ）の原料を、副押出機に表層（Ｘ）の原料を供給しそれぞれ２８０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行った後に、Ｔダイ複合口金内で、表層（Ｘ）が芯層（Ｙ）の両表層に積層（Ｘ／Ｙ／Ｘ）されるよう合流せしめた。 (Examples 2, 8, 11 to 20)
After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material for the core layer (Y) was supplied to the main extruder and the raw material for the surface layer (X) was supplied to the sub-extruder. After melt extrusion at a temperature, after filtration through a 30 μm cut filter, the surface layer (X) was joined to be laminated (X / Y / X) on both surface layers of the core layer (Y) in a T-die composite die. .
　次いで、シート状に押出して溶融シートとし、該溶融シートを、表面温度２５℃に保たれたドラム上に静電印加法で密着冷却固化させて未延伸フィルムを得た。続いて、該未延伸フィルムを７０℃の温度に加熱したロール群で予熱した後、赤外線ヒーターで両面から照射しながら、長手方向（縦方向）に表２の倍率にて延伸を行い、２５℃の温度のロール群で冷却して一軸延伸フィルムを得た。その後、一軸延伸フィルムの両端をクリップで把持しながらテンター内の１１０℃の予熱ゾーンに導き、引き続き１２０ ℃ で長手方向に垂直な方向（横方向）に表２の倍率にて延伸した。さらに引き続いて、テンター内の熱処理ゾーンで表２の温度の熱処理を施し、次いで均一に徐冷後、ロールに巻き取り、表２に記載の厚みの成形用白色ポリエステルフィルムを得た。 Next, the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film. Subsequently, the unstretched film was preheated with a roll group heated to a temperature of 70 ° C., and then stretched at a magnification of Table 2 in the longitudinal direction (longitudinal direction) while irradiating from both sides with an infrared heater. A uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C. preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C. Subsequently, heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
　（実施例１０）
表１に示した組成の原料を１８０℃の温度で６時間真空乾燥した後に主押出機に芯層（Ｙ）の原料を供給し２８０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行い、副押出機に表層（Ｘ）の原料を供給し２７０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行った後に、Ｔダイ複合口金内で、表層（Ｘ）が芯層（Ｙ）の両表層に積層（Ｘ／Ｙ／Ｘ）されるよう合流せしめた。 (Example 10)
After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material of the core layer (Y) was supplied to the main extruder, and after melt extrusion at a temperature of 280 ° C., filtration was performed with a 30 μm cut filter. The raw material of the surface layer (X) is supplied to the sub-extruder, melt-extruded at a temperature of 270 ° C., filtered through a 30 μm cut filter, and then the surface layer (X) is the core layer (Y) in the T-die composite die. It was made to merge so that it might be laminated | stacked on a surface layer (X / Y / X).
　次いで、シート状に押出して溶融シートとし、該溶融シートを、表面温度２５℃に保たれたドラム上に静電印加法で密着冷却固化させて未延伸フィルムを得た。続いて、該未延伸フィルムを７０℃の温度に加熱したロール群で予熱した後、赤外線ヒーターで両面から照射しながら、長手方向（縦方向）に表２の倍率にて延伸を行い、２５℃の温度のロール群で冷却して一軸延伸フィルムを得た。その後、一軸延伸フィルムの両端をクリップで把持しながらテンター内の１１０℃の予熱ゾーンに導き、引き続き１２０ ℃ で長手方向に垂直な方向（横方向）に表２の倍率にて延伸した。さらに引き続いて、テンター内の熱処理ゾーンで表２の温度の熱処理を施し、次いで均一に徐冷後、ロールに巻き取り、表２に記載の厚みの成形用白色ポリエステルフィルムを得た。 Next, the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film. Subsequently, the unstretched film was preheated with a roll group heated to a temperature of 70 ° C., and then stretched at a magnification of Table 2 in the longitudinal direction (longitudinal direction) while irradiating from both sides with an infrared heater. A uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C. preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C. Subsequently, heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
　（比較例１、２、６）
表１に示した組成の原料を１８０℃の温度で６時間真空乾燥した後に主押出機に芯層（Ｙ）の原料を、副押出機に表層（Ｘ）の原料を供給しそれぞれ２８０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行った後に、Ｔダイ複合口金内で、表層（Ｘ）が芯層（Ｙ）の両表層に積層（Ｘ／Ｙ／Ｘ）されるよう合流せしめた。 (Comparative Examples 1, 2, 6)
After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material for the core layer (Y) was supplied to the main extruder and the raw material for the surface layer (X) was supplied to the sub-extruder. After melt extrusion at a temperature, after filtration through a 30 μm cut filter, the surface layer (X) was joined to be laminated (X / Y / X) on both surface layers of the core layer (Y) in a T-die composite die. .
　次いで、シート状に押出して溶融シートとし、該溶融シートを、表面温度２５℃に保たれたドラム上に静電印加法で密着冷却固化させて未延伸フィルムを得た。続いて、該未延伸フィルムを７０℃の温度に加熱したロール群で予熱した後、赤外線ヒーターで両面から照射しながら、長手方向（縦方向）に表２の倍率にて延伸を行い、２５℃の温度のロール群で冷却して一軸延伸フィルムを得た。その後、一軸延伸フィルムの両端をクリップで把持しながらテンター内の１１０℃の予熱ゾーンに導き、引き続き１２０ ℃ で長手方向に垂直な方向（横方向）に表２の倍率にて延伸した。さらに引き続いて、テンター内の熱処理ゾーンで表２の温度の熱処理を施し、次いで均一に徐冷後、ロールに巻き取り、表２に記載の厚みの白色ポリエステルフィルムを得た。 Next, the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film. Subsequently, the unstretched film was preheated with a roll group heated to a temperature of 70 ° C., and then stretched at a magnification of Table 2 in the longitudinal direction (longitudinal direction) while irradiating from both sides with an infrared heater. A uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C. preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C. Subsequently, heat treatment at the temperature shown in Table 2 was performed in the heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film having the thickness shown in Table 2.
　（比較例３～５）
表１に示した組成の原料を１８０℃の温度で６時間真空乾燥した後に主押出機に芯層（Ｙ）の原料を供給し２８０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行い、副押出機に表層（Ｘ）の原料を供給し２９０℃の温度で溶融押出後３０μｍカットフィルターにより濾過を行った後に、Ｔダイ複合口金内で、表層（Ｘ）が芯層（Ｙ）の両表層に積層（Ｘ／Ｙ／Ｘ）されるよう合流せしめた。 (Comparative Examples 3 to 5)
After the raw materials having the composition shown in Table 1 were vacuum-dried at a temperature of 180 ° C. for 6 hours, the raw material of the core layer (Y) was supplied to the main extruder, and after melt extrusion at a temperature of 280 ° C., filtration was performed with a 30 μm cut filter. The raw material of the surface layer (X) is supplied to the sub-extruder, melt-extruded at a temperature of 290 ° C., filtered through a 30 μm cut filter, and then the surface layer (X) is the core layer (Y) in the T-die composite die. It was made to merge so that it might be laminated | stacked on a surface layer (X / Y / X).
　次いで、シート状に押出して溶融シートとし、該溶融シートを、表面温度２５℃に保たれたドラム上に静電印加法で密着冷却固化させて未延伸フィルムを得た。続いて、該未延伸フィルムを８０℃の温度に加熱したロール群で予熱した後、赤外線ヒーターで両面から照射しながら、長手方向（縦方向）に表２の倍率にて延伸を行い、２５℃の温度のロール群で冷却して一軸延伸フィルムを得た。その後、一軸延伸フィルムの両端をクリップで把持しながらテンター内の１１０℃の予熱ゾーンに導き、引き続き１２０ ℃ で長手方向に垂直な方向（横方向）に表２の倍率にて延伸した。さらに引き続いて、テンター内の熱処理ゾーンで表２の温度の熱処理を施し、次いで均一に徐冷後、ロールに巻き取り、表２に記載の厚みの成形用白色ポリエステルフィルムを得た。 Next, the sheet was extruded into a molten sheet, and the molten sheet was closely cooled and solidified by an electrostatic application method on a drum maintained at a surface temperature of 25 ° C. to obtain an unstretched film. Subsequently, the unstretched film was preheated with a roll group heated to a temperature of 80 ° C., and then stretched at a magnification in Table 2 in the longitudinal direction (longitudinal direction) while being irradiated from both sides with an infrared heater, and 25 ° C. A uniaxially stretched film was obtained by cooling with a roll group at a temperature of 5 ° C. Thereafter, both ends of the uniaxially stretched film were guided to a 110 ° C. preheating zone in the tenter while being gripped by clips, and subsequently stretched at a magnification of Table 2 in a direction perpendicular to the longitudinal direction (lateral direction) at 120 ° C. Subsequently, heat treatment at a temperature shown in Table 2 was performed in a heat treatment zone in the tenter, and after uniform cooling, the film was wound on a roll to obtain a white polyester film for molding having a thickness shown in Table 2.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　本発明は高い反射率と成形性を備えるのみならず、高い形状維持性を持つため、直下型のＬＥＤバックライトユニットに用いられる光反射板などとして好適に用いられる。
  Since the present invention has not only high reflectivity and moldability but also high shape maintainability, it is suitably used as a light reflector used in a direct type LED backlight unit.

Claims (7)

  1. 少なくとも三層からなり、表層のガラス転移温度（Ｔｇ）が８０℃以上１２０℃未満であり、フィルムの比重が０．８～１．１であることを特徴とする成形用白色ポリエステルフィルム。 A white polyester film for molding, comprising at least three layers, a glass transition temperature (Tg) of a surface layer of 80 ° C. or higher and lower than 120 ° C., and a specific gravity of the film of 0.8 to 1.1.
  2. 表層のガラス転移温度（Ｔｇ）+６０℃における貯蔵弾性率（Ｅ’）が１０ＭＰａ以上３００ＭＰａ以下である請求項１に記載の成形用白色ポリエステルフィルム The white polyester film for molding according to claim 1, wherein the storage elastic modulus (E ') at the glass transition temperature (Tg) + 60 ° C of the surface layer is 10 MPa or more and 300 MPa or less.
  3. 芯層にボイド核剤を含有する気泡を有していることを特徴とする請求項１または２に記載の成形用白色ポリエステルフィルム。 The white polyester film for molding according to claim 1 or 2, wherein the core layer has bubbles containing a void nucleating agent.
  4. 反射率９８％以上かつ透過率３％未満である請求項１に記載の成形用白色ポリエステルフィルム The white polyester film for molding according to claim 1, which has a reflectance of 98% or more and a transmittance of less than 3%.
  5. 請求項１に記載の成形用白色ポリエステルフィルムを成形した白色樹脂成形体 The white resin molding which shape | molded the white polyester film for shaping | molding of Claim 1
  6. ＬＥＤ照明ユニットに使用される請求項５に記載の白色樹脂成形体。 The white resin molding of Claim 5 used for an LED lighting unit.
  7. 直下型ＬＥＤバックライトユニットに使用される請求項５に記載の白色樹脂成形体。
          The white resin molded product according to claim 5, which is used for a direct type LED backlight unit.
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