JP2000103877A - Polyester film for coating plywood and coated plywood on which the film is laminated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester film for coating plywoods which satisfies well-balancedly all of the fabricability, solvent resistance, stain resistance, heat resistance, design properties and surface properties, and a coated plywood (decorative plywood) formed by laminating the polyester film on at least one side of a plywood (particle board). SOLUTION: The polyester film for coating plywoods is a biaxially oriented film made of a polyester in which trimethylene terephthalate units account for 80 mol% or more of the total repeating units and has a heat-shrinkage rate of 0-3% in the width direction (TD) after heat treatment at 105 deg.C for 30 minutes and a center-line mean roughness (Ra) of 5-500 nm. The coated plywood is formed by laminating the polyester film for coating plywoods on at least one side of a plywood.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film for coating plywood and a coated plywood obtained by laminating the same. More particularly, it is excellent in moldability, stain resistance, heat resistance, design and surface properties, and is used for high-end furniture and the like. The present invention relates to a plywood-coating polyester film useful for the production of a coated plywood and a coated plywood obtained by laminating the same.

[0002]

2. Description of the Related Art Coated plywood obtained by coating a plywood (particle board) with a thin resin layer has been widely used in the past because of its excellent design. Among them, those provided with a printed layer above or below a resin thin layer are used as decorative plywood. In particular, decorative plywood in which a vinyl chloride resin layer (sheet) having a printing layer is laminated on plywood is widely used for building materials and furniture. However, the decorative plywood laminated with vinyl chloride resin is easily scratched, and the vinyl chloride resin layer on the surface deteriorates due to the effects of ultraviolet rays, heat, moisture, etc. with the lapse of use time, and the plasticizer in the vinyl chloride resin is Since it is volatilized and lost, it has disadvantages such as remarkable decrease in surface properties and extreme discoloration.

In order to improve such disadvantages, a method of applying a hard coat layer of an acrylic resin or the like on a coated vinyl chloride resin has been proposed. In addition, such a hard coat layer is required to have flatness in order to make the surface glossy. However, there are drawbacks such as poor work efficiency in applying the flatness of the hard coat layer satisfactorily.

[0004] Therefore, a method of applying a hard coat to a polyolefin resin-based film is conceivable. However, the method using a polyolefin resin is inferior in heat resistance of the polyolefin resin. There are drawbacks such as lack of flatness and loss of luster.

[0005] A method using a biaxially stretched polyethylene terephthalate film having excellent properties such as solvent resistance, stain resistance, heat resistance, economy and surface properties can be considered. However, this polyethylene terephthalate film has a drawback that molding processability is inferior due to its high rigidity.

[0006]

SUMMARY OF THE INVENTION A first object of the present invention is to solve the above-mentioned problems of coated plywood, and to improve molding processability, solvent resistance, stain resistance, heat resistance, design and surface properties. An object of the present invention is to provide a plywood-coated polyester film that satisfies a good balance.

A second object of the present invention is to provide a coated plywood (decorative plywood) in which the polyester film is laminated on at least one surface of a plywood (particle board).

[0008]

SUMMARY OF THE INVENTION Two objects of the present invention are as follows.
According to the present invention, this is achieved by the following two configurations. 1. A biaxially oriented film comprising a polyester in which trimethylene terephthalate units are at least 80 mol% of all repeating units, and the film has a heat shrinkage in the width direction (TD) of 0 to 3% after heat treatment at 105 ° C. for 30 minutes. And a center line average roughness (Ra) of 5 to 500 nm. 2. A coated plywood obtained by laminating the polyester film for coating plywood.

[Polytrimethylene terephthalate] The polytrimethylene terephthalate used in the present invention is a polyester containing terephthalic acid as a main acid component and 1,3-propanediol as a main glycol component.
As the polytrimethylene terephthalate, a homopolymer having trimethylene terephthalate as a total repeating unit or a copolymer having trimethylene terephthalate at least 80 mol%, preferably 90 mol%, of all the repeating units is preferably used. If the repeating unit of trimethylene terephthalate is less than 80 mol%, the crystallinity is lost, and the properties inherent in polytrimethylene terephthalate, such as mechanical strength, are deteriorated, and the film forming property is reduced.

In the case of a copolymer, a compound having two ester-forming functional groups in a molecule can be used as a copolymerization component constituting a copolymer other than trimethylene terephthalate as a main component. Oxalic acid, adipic acid, phthalic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, dodecanedicarboxylic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,
4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, phenylindanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-
Dicarboxylic acids such as naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, tetralindicarboxylic acid, decalindicarboxylic acid, diphenyletherdicarboxylic acid; oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid; or ethylene Glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, cyclohexane methylene glycol, neopentyl glycol, ethylene oxide adduct of bisphenolsulfone, ethylene oxide adduct of bisphenol A, diethylene glycol, polyethylene oxide glycol, polyethylene glycol, polypropylene glycol, Dihydric alcohols such as polytetramethylene glycol can be preferably used. .

These compounds can be used alone or in combination of two or more. Of these, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and p
-Oxybenzoic acid and the glycol component are ethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and ethylene oxide adducts of bisphenolsulfone.

The polytrimethylene terephthalate may be one in which a terminal hydroxyl group and / or a carboxyl group is partially or entirely blocked with a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol. A very small amount of a trifunctional or higher functional ester-forming compound such as glycerin or pentaerythritol may be copolymerized within a range where a substantially linear polymer can be obtained.

Further, the polytrimethylene terephthalate film of the present invention may be composed of a mixture of an organic polymer in addition to the main component polytrimethylene terephthalate. Such organic polymers include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, polytetramethylene isophthalate, polyhexamethylene tere (iso) phthalate, polyethylene-4,4'-tetramethylenediphenyldicarboxylate, and polyethylene-2,6. -Naphthalenedicarboxylate, polyethylene-2,7-naphthalenedicarboxylate, polytrimethylene-2,6-naphthalenedicarboxylate, polybutylene-2,6-naphthalenedicarboxylate, polycyclohexanedimethyleneterephthalate, polyneopent Len-2,6-naphthalenedicarboxylate, poly (bis (4-ethyleneoxyphenyl) sulfone) -2,6-naphthalenedicarboxylate and the like can be mentioned. Among them, polyethylene isophthalate, polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene tere (iso) phthalate, polyethylene-2,6-naphthalenedicarboxylate, polytrimethylene-2,
6-naphthalenedicarboxylate, polybutylene-
2,6-naphthalenedicarboxylate, poly (bis (4-ethyleneoxyphenyl) sulfone) -2,6-
Naphthalenedicarboxylate is preferred.

In the polytrimethylene terephthalate film of the present invention, not only one kind but also two or more kinds of these organic polymers are used in an amount of 20% by mole, preferably up to 10% by mole of the polymer in the polytrimethylene terephthalate. And can be used to form a mixture mixed therewith. If the mixing amount of the mixture exceeds the above range, the crystallinity is lowered, and properties inherent to trimethylene terephthalate, such as mechanical strength and moldability, are deteriorated.
The production of such a mixture can be carried out by a generally known method for producing a polyester composition.

The polyester in the present invention is a conventionally known method, for example, a method of directly obtaining a low-polymerized polyester by the reaction of dicarboxylic acid and glycol, or a conventionally known transesterification catalyst for converting a lower alkyl ester of dicarboxylic acid and glycol. For example, after reacting with one or more compounds containing sodium, potassium, magnesium, calcium, zinc, strontium, titanium, zirconium, manganese, and cobalt, polymerization is carried out in the presence of a polymerization catalyst. Antimony trioxide, antimony compounds such as antimony pentoxide, germanium compounds typified by germanium dioxide, tetraethyl titanate, tetrapropyl titanate, tetraphenyl titanate or partial hydrolysates thereof, titanyl ammonium oxalate as the polymerization catalyst And titanium compounds such as potassium titanyl oxalate and titanium trisacetylacetonate.

The polyester can be formed into chips after melt polymerization and solid-phase polymerized under reduced pressure under heating or in an inert gas stream such as nitrogen.

[Additives] The polyester film of the present invention may contain additives such as a lubricant, a stabilizer, a flame retardant and the like. At the time of film production, processing, in order to improve the runnability and handling during use, in order to improve the slipperiness of the film, a small percentage of inert fine particles such as inorganic particles, organic particles, and crosslinked polymer particles are contained. Is preferred.

The inorganic particles are not particularly limited, but include calcium carbonate, porous silica, spherical silica, kaolin, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, and oxide. Examples thereof include aluminum, silicon oxide, titanium oxide, zirconium oxide, and lithium fluoride. Among them, spherical silica and porous silica are preferable.

Examples of the organic particles include calcium oxalate and terephthalates such as calcium, barium, zinc, manganese and magnesium.

Examples of the crosslinked polymer particles include homopolymers and copolymers of vinyl monomers such as divinylbenzene, styrene, acrylic acid, methacrylic acid, acrylic acid and methacrylic acid, and polytetrafluoroethylene. Organic fine particles such as silicone resin, benzoguanamine resin, thermosetting epoxy resin, unsaturated polyester resin, thermosetting urea resin, and thermosetting phenol resin are also used. Among these, silicone resin particles are preferred.

The average particle size of these lubricants is 0.0
The thickness is preferably 1 to 5 μm, more preferably 0.05 to 4 μm, and particularly preferably 0.1 to 3 μm. Further, the addition amount is preferably 0.01 to 4% by weight, more preferably 0.02 to 3.0% by weight, and particularly preferably 0.04 to 2.5% by weight. Generally, it is preferable to add a small amount of particles having a large particle diameter and a large amount of particles having a small particle diameter. Further, the film can be made opaque by intentionally adjusting the content of the lubricant. For example, by adding 10 to 15% by weight of titanium dioxide,
It can be a white film.

The inert fine particles to be added to the film may be a single component selected from those exemplified above, or a multi-component containing two or more than three components.

The polyester film of the present invention comprises a pigment,
UV absorbers, release agents, lubricants, flame retardants, antistatic agents,
Polysiloxane and the like can be blended.

The timing of adding the inert fine particles and other additives is not particularly limited as long as it is a stage before polytrimethylene terephthalate is formed. For example, it may be added at the polymerization stage. It may be added.

[Polyester Film] The polyester film of the present invention only needs to have a thickness generally used as a plywood coating film, and is 5 to 100 μm, preferably 5 to 75 μm, and particularly preferably 5 to 50 μm. Is the thickness. The thickness unevenness is preferably 12% or less, and 10% or less.
% Or less, more preferably 8% or less.

The polyester film of the present invention can be produced by a conventionally known method. For example,
The dried polyester is melted using a known extruder, the molten polyester is extruded into a sheet, and the unstretched sheet obtained by quenching and solidifying on a rotary cooling drum is biaxially stretched to form a biaxially stretched film. Method.

As this stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used, but the sequential biaxial stretching method is preferred from the viewpoint of workability in a coating step described later. As the stretching conditions in the sequential biaxial stretching method, the unstretched sheet is 40 to 9
The film is stretched 1.5 to 6 times in the longitudinal direction at 0 ° C. by an infrared heating type longitudinal stretching machine. A roll heating type vertical stretching machine can also be used, but an infrared heating type is preferred because defects such as scratches are likely to occur on the film surface. After longitudinal stretching, the film is further stretched 1.5 to 6 times in the transverse direction at 40 to 90 ° C.
A desired polyester film can be obtained by performing a heat treatment at a temperature of 210 ° C. for 1 to 100 seconds. In the heat treatment step, the interval between the clip rails is adjusted so that the downstream side is narrowed, and the relaxation treatment is performed in the width direction of the film.
This is effective as a means for reducing the heat shrinkage in the lateral direction.
Further, multi-stage stretching in which the above-described stretching in the longitudinal direction and / or the transverse direction is divided into a plurality of stages may be used. Further, the polyester film of the present invention may be laminated with another film by a co-extrusion method or an extrusion laminating method during the film forming step, or may be laminated with an adhesive after forming the film.

The intrinsic viscosity of this film is 0.40 dl /
g and less than 0.90 dl / g are preferred.

[Heat Shrinkage] The polyester film of the present invention needs to have a heat shrinkage in the width direction (TD) of 0 to 3% after heat treatment at 105 ° C. for 30 minutes.

The heat shrinkage of the film affects the flatness of the film in the curing step of the hard coat applied on at least one side of the polyester film.
That is, if the heat shrinkage in the width direction after the heat treatment at 105 ° C. for 30 minutes is less than 0% (the film expands), the flatness cannot be maintained due to the elongation of the film. On the other hand, if the heat shrinkage in the width direction after heat treatment at 105 ° C. for 30 minutes is more than 3%, the film shrinks and heat wrinkles occur. For this reason, the flatness of the applied hard coat layer is deteriorated, and the gloss is lost. Therefore, the heat shrinkage in the width direction is preferably 0 to 2%,
-1% is particularly preferred.

[Center Line Average Roughness (Ra)] The center line average roughness (hereinafter sometimes abbreviated as Ra) of the film of the present invention.
Is 5 to 500 nm, preferably 5 to 400 n
m, particularly preferably from 10 to 350 nm.

When Ra is less than 5 nm, the film has poor handling properties, easily causes blocking, and causes surface defects. On the other hand, exceeding 500 nm means that the particle size of the added lubricant particles is large or the amount of the added lubricant particles is too large, and cutting during the production of the film occurs frequently, and the productivity is reduced.

[Young's modulus] The Young's modulus of the film of the present invention is 110 to 5 in both the longitudinal direction (MD) and the width direction (TD).
It is preferably 50 kg / mm ² ,
0 kg / mm ² , more preferably 180 to 4 kg / mm ^2.
Particularly preferred is 50 kg / mm ² . When the Young's modulus is less than 110 kg / mm ² , the rigidity of the film is low,
Pinholes can easily occur, while 550k
If it exceeds g / mm ² , the rigidity is too high, and the workability may deteriorate.

[Density] The density of the film of the present invention is 1.3.
It is preferably from 15 to 1.365 g / cm ³ . When the density exceeds 1.365 g / cm ³ , the toughness of the film is reduced, and the processability may be deteriorated.
If it is less than 5 g / cm ³ , the mechanical strength is insufficient, and the gas barrier property may be reduced.

[0035] [refractive index in the thickness direction (n _z)] refractive index in the thickness direction of the film of the present invention (n _z) is preferably at 1.570 or less, it is from 1.420 to 1.570 More preferred. When the refractive index in the thickness direction exceeds 1.570, the thickness unevenness of the film is large, and the flatness may be deteriorated. On the other hand, when the refractive index in the thickness direction is less than 1.420, cutting during film production occurs frequently, and Performance may be reduced.

[Oxygen Permeability Coefficient] The oxygen permeability coefficient of the film of the present invention is 40 cc · cm / cm ² · sec · cmHg.
It is as follows. 40cc ・ cm / cm ²・ sec ・ cmH
If it exceeds g, the gas barrier properties as a coating material may be insufficient.

[Hard Coat Layer] It is preferable to provide a hard coat layer on one side of the polyester film of the first constitution of the present invention.

As the compound for forming the hard coat layer, for example, acrylic, urethane, phenol,
A hard coat agent mainly composed of one or more known thermosetting resins such as melamine-based, polyester-based, epoxy-based, and silicone-based resins can be used.

The hard coat layer can be provided by a known method. For example, after a hard coat agent is applied to one side of a polyester film, the temperature is 100 ° C. or more, particularly 110 to 1
It can be provided by heating and curing at a temperature of 60 ° C. for several minutes to several tens of minutes. More specifically, in the case of Shin-Etsu silicone hard coating agent, 3
It is preferable to cure by heating for 0 to 60 minutes or by heating at 150 ° C. for several minutes.

The thickness of the hard coat layer is preferably about 2 to 10 μm. If the thickness is too large, cracks may easily occur.

[Coated Plywood] The coated plywood of the second configuration of the present invention can be manufactured by laminating the above-mentioned polyester film of the first configuration of the present invention on the plywood. The laminating method includes, for example, a method of directly laminating and coating a plywood using an adhesive. In this method, it is preferable to provide a polyvinyl chloride layer (sheet layer) between the polyester film and the adhesive layer. . This polyvinyl chloride layer preferably has a thickness of 500 μm to 1 mm.

As polyvinyl chloride, polyvinyl chloride,
Copolymers of vinyl chloride with other monomers copolymerizable therewith (for example, vinyl acetate, acrylate, etc.) can be mentioned.

It is preferable to first laminate a polyvinyl chloride layer (sheet) and a polyester film, and then laminate the resulting laminate to plywood using an adhesive. In particular, when a hard coat layer is provided on a polyester film, the hard coat layer is laminated so as to be opposite to the surface on which the plywood or polyvinyl chloride layer is laminated. Further, when a printing layer is provided in the structure of the laminate, it is preferable to provide a printing layer between the polyester film and the polyvinyl chloride layer.

The plywood in the present invention is a plate obtained by molding and pressing with an adhesive using a suitable piece of wood as a main raw material.
Usually, the specific gravity is 0.4 or more. This plywood is usually called a particle boat.

[0045]

The present invention will be described below in detail with reference to examples. Various physical properties and characteristics in the present invention were measured by the following methods.

(1) Calculation of Component Amounts (Mole Ratio of Main Component, Copolymer Component) of Trimethylene Terephthalate A film sample was measured using a solvent (CDCl ₃ : CF ₃ COO).
(D = 1: 1), and ¹ H-NMR measurement is carried out, and it is calculated by the integration ratio of each obtained signal.

(2) Heat Shrinkage A film whose length has been measured in advance is placed in a thermostatic chamber set at 105 ° C., held for 30 minutes, taken out, returned to room temperature, and read out a change in its dimensions. . From the length before heat treatment (L ₀ ) and the length after heat treatment (L), the heat shrinkage is determined by the following equation. Heat shrinkage = (L ₀ −L) × 100 / L ₀ (%)

(3) Center Line Average Roughness (Ra) Both the front and back sides of the film are measured with a surface roughness meter (Surfcom 111A, Tokyo Seimitsu Co., Ltd.), and the average value is calculated to be the center line average roughness.

(4) Young's modulus A sample was cut into a width of 10 mm and a length of 150 mm.
Set to 00 mm, pulling speed 10 mm / min, chart speed 5
It is pulled with an Instron type universal tensile tester at 00 mm / min. The measurement is performed in both the longitudinal direction (MD) and the width direction (TD), and the Young's modulus is calculated from the tangent at the rising edge of the obtained load-elongation curve.

(5) Density The density is measured by a flotation method at 25 ° C. in a density gradient tube using an aqueous solution of calcium nitrate.

(6) Refractive index in the thickness direction ( _nz ) An Abbe refractometer manufactured by Atago Co., Ltd. was used.
Using a line, the refractive index in the film thickness direction is measured. The measurement is performed on both the front and back sides of the film sample, and the average value is defined as the refractive index _nz .

(7) Oxygen Permeability Coefficient Based on ASTM D1435-75, the oxygen permeability coefficient of the film at 25 ° C. was calculated using a gas permeability measuring device (GTR tester M-C1 manufactured by Toyo Seiki Seisaku-sho, Ltd.) Oxygen permeability coefficient per unit thickness [unit: cc. cm / c
m ² · sec · cmHg].

(8) Handling Property The handling property of the film was evaluated according to the following criteria. ：: Good handling properties with no blocking. There are no surface imperfections caused by blocking. ：: Almost no blocking occurs and the handling properties are almost good. Almost no surface imperfections caused by blocking are seen and can be used satisfactorily. X: Blocking occurs and handling properties are poor. Unusable due to frequent surface defects caused by blocking.

(9) Practical Properties After applying an acrylic hard coat agent to one side of the polyester film and subjecting it to a curing treatment, the polyester film was adhered to a PVC resin sheet provided with a 500 μm print layer using an ester adhesive. A laminate was formed, and the laminate was laminated to a door-shaped plywood using an epoxy adhesive at a temperature of 80 ° C. to obtain a decorative plywood.

The following observations were made on this decorative plywood,
Each was evaluated according to the following criteria. (A) Workability ：: The laminate follows the shape of the plywood, and there is no lifting at all. Δ: The laminate substantially follows the shape of the plywood, and hardly floats. ×: The laminate does not follow the shape of the plywood at all and there is a lift. (B) Thermal wrinkles A: The film has no thermal wrinkles during curing of the hard coat and has a glossy surface. ：: The film was glossy on the surface without heat wrinkles during curing of the hard coat, but was somewhat less. Δ: A little heat wrinkle was generated in the film during curing of the hard coat, and the surface was not very glossy. ×: Thermal wrinkles are generated in the film during curing of the hard coat, and the surface has no gloss at all.

[Example 1] Dimethyl terephthalate 100
A transesterification reaction was performed by using 60 parts by weight of 1,3-propanediol and 0.08 part by weight of tetrabutyl titanate. Then, as a lubricant, an average particle size of 1.5
μm spherical silica particles were added so as to be 0.1% by weight per polymer, and a polycondensation reaction was carried out under high vacuum to obtain polytrimethylene terephthalate having an intrinsic viscosity of 0.65 dl / g.

The polytrimethylene terephthalate is melt-extruded into a sheet on a rotary cooling drum to obtain an unstretched sheet, and the unstretched sheet is placed in a machine axial direction (longitudinal direction).
The film was stretched three times to obtain a uniaxially stretched film. Subsequently, the film was stretched 3.6 times in the transverse direction, and further subjected to a 5% relaxation treatment in the width direction while being heat-set at 180 ° C. to obtain a biaxially stretched film having a thickness of 15 μm. Table 1 shows the properties of this film. As is clear from Table 1, the film of Example 1 satisfied all the required characteristics.

Examples 2 to 6 The same conditions as in Example 1 except that the type and proportion of the copolymer components, the type of inert fine particles, the average particle size, the amount added, and the stretching conditions were changed as shown in Table 1. To obtain a biaxially stretched film having a thickness of 15 μm. Note that the relaxation rate in the width direction in Example 2 was 2%. Table 1 shows the properties of these films. As is clear from Table 1, the films of Examples 2 to 6 satisfied all the required characteristics.

Comparative Example 1 Dimethyl Terephthalate 100
A transesterification reaction was carried out using 60 parts by weight of ethylene glycol, 0.038 parts by weight of manganese acetate and 0.041 parts by weight of antimony trioxide. Then, 0.097 parts of trimethyl phosphate and an average particle size of 1.5
μm spherical silica content of 0.1% by weight per polymer
And subjected to a polycondensation reaction under a high vacuum to obtain polyethylene terephthalate having an intrinsic viscosity of 0.64 dl / g. This polyethylene terephthalate was formed under the conditions shown in Table 1 to obtain a biaxially oriented film having a thickness of 15 μm. Table 1 shows the properties of the obtained biaxially oriented film. This film had poor flexibility and poor workability.

[Comparative Examples 2 to 6] The same conditions as in Example 1 except that the type and proportion of the copolymer component, the type of inert fine particles, the average particle size, the amount added, and the stretching conditions were changed as shown in Table 1. To obtain a biaxially stretched film having a thickness of 15 μm. The relaxation rate in the width direction was 12% for Comparative Example 4, 0% for Comparative Example 5, and 5% for the others. Table 1 shows the properties of the obtained biaxially oriented film. Since these films do not satisfy all the requirements of the present invention, disadvantages as plywood coating films are recognized.

[0061]

[Table 1]

[0062]

The polyester film for coating plywood of the present invention is excellent in workability and surface properties in forming after laminating with plywood, and is extremely useful for producing coated plywood.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // B29K 67:00 B29L 7:00 F term (reference) 4F071 AA45 AF07Y AF20Y AF27Y AF31Y AF61Y BB06 BB08 BC01 BC08 BC11 BC16 4F100 AA20H AK15 AK25 AK33 AK36 AK41A AK41J AK51 AK52 AK53 AP02C BA02 BA03 BA05 BA06 BA07 BA10A BA10B BA10C BA13 CA19 CC00B DD07A EJ38A GB81 JA03A JA13A JD03A JK07A JK12AJA14AJK12A01 QG18 QL17 QM11 QW07 4J002 CF031 FD010 GF00

Claims (6)

[Claims] 1. A biaxially oriented film comprising a polyester having trimethylene terephthalate units in an amount of at least 80 mol% of all repeating units.
A polyester film for coating plywood, wherein the heat shrinkage in the width direction (TD) after heat treatment for 0 minutes is 0 to 3% and the center line average roughness (Ra) is 5 to 500 nm. 2. The film having a Young's modulus in the longitudinal direction (M
D), 110 to 550 kg / mm in both width direction (TD)
^2. The plywood-coated polyester film according to claim 1, which is ² . 3. The film has a density of 1.315 to 1.36.
The polyester film for coating plywood according to claim 1 or 2, wherein the polyester film has a refractive index ( _nz ) of 5 g / cm ³ and a thickness direction of 1.570 or less. 4. The film has an oxygen permeability coefficient of 40 cc · c.
m / cm ² · sec · cmHg or less.
The polyester film for covering plywood according to any one of the above. 5. The polyester film for coating plywood according to claim 1, wherein a hard coat layer is provided on one side of the film. 6. A coated plywood in which the plywood-coated polyester film according to claim 1 is laminated on at least one surface of the plywood.