JP2003334912A - Easily adhesive high-transparency polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film having outstanding transparency, surface flatness and easy adhesive properties. <P>SOLUTION: The easily adhesive high-transparency polyester film is obtained by providing a coating layer containing a polyester resin and an acrylic resin with an oxazoline group and a polyalkylene oxide chain on at least the single surface of a polyester film substantially containing no particles and characterized in that a dimensional change ratio at 200°C under a load of 140 g/mm<SP>2</SP>in the longitudinal direction of the film is -2 to +2%. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an easy-adhesive film, and more particularly to a polyester film having an easy-adhesive coating film made of a specific composition formed on at least one side of a polyester film.

[0002]

2. Description of the Related Art Polyester films, especially biaxially stretched films of polyethylene terephthalate and polyethylene naphthalate, have excellent mechanical properties, heat resistance and chemical resistance, so that they are magnetic tape, ferromagnetic thin film tape, photographic film, packaging. It is widely used as a material for films for electronic parts, films for electronic parts, films for electrical insulation, films for metal laminating, films to be stuck on the surface of glass displays, etc., and films for protecting various members.

In recent years, polyester films have been widely used especially for various optical films, and are used for prism lens sheets of liquid crystal display devices, base films for touch panels, backlights, antireflection films, and explosion-proof displays. It is used for applications such as base films. The base film used for such an optical film is required to have excellent transparency, excellent adhesion to prism lenses, hard coats, pressure sensitive adhesives, antireflection treatment and the like and surface flatness.

Biaxially oriented polyester films generally have poor adhesion to other materials, for example, prism lenses and a hard coat containing acrylic resin as a main component. It has been proposed to stack and use an easy-adhesion layer such as a urethane resin (for example, JP-A-10-11921).
5, JP-A-2000-246855).

[0005]

However, the adhesive force may be insufficient in the case where the easily adhesive layer made of these resins is formed. For example, a film for CRT has good adhesion to the hard coat layer but insufficient adhesion to the adhesive layer on the opposite side, and thus lacks versatility. Further, since the optical film is required to have transparency and surface flatness, it is necessary to reduce the particles usually added as an anti-blocking agent in the polyester film to the utmost or not add them at all.

On the other hand, in order to satisfy the above-mentioned easy-adhesion property, a resin having a low glass transition temperature has hitherto been used for the easy-adhesion layer, but for a film having a highly flat surface,
When a resin with a low glass transition temperature is used for the easy-adhesion layer, sticking occurs when the films are wound or laminated, the films do not slide and the handling property deteriorates, and it is difficult to slip, so film formation and processing There is a problem that the surface is easily scratched during the process.

Further, the polyester film used for optical applications has a gas barrier layer, a conductor layer,
A semiconductor layer, a light-emitting layer, etc. are laminated, and in the lamination of these layers, vapor deposition, ion plating, sputtering, plasma CDV, etc. are used. When applying the above method, a certain tension is applied to the film roll, and it is carried out while maintaining the flatness of the film, but although there are high and low depending on the method, the film is exposed to a considerably high temperature, so the film If the expansion and contraction behavior of the is significantly different from the expansion and contraction behavior of the laminated body, there is a problem that the laminated body is cracked, wrinkled, and the like and sufficient performance cannot be exhibited.

The present invention solves the above problems of the prior art and is excellent in adhesive strength with layers used in various optical applications.
Moreover, it is an object to provide a polyester film having excellent transparency and surface flatness.

[0009]

That is, according to the present invention, a coating layer containing a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain is provided on at least one surface of a polyester film containing substantially no particles. Highly transparent and easily adhesive polyester film having a dimensional change rate of −2 to + 2% at 200 ° C. under a load of 140 g / mm ^{2 in} the longitudinal direction of the film. It is a film.

In a preferred embodiment of the present invention, the haze value of the polyester film is 1.5%, and the three-dimensional center line average roughness of the film surface is 0.0001-0.
When the thickness is 02 μm, the polyester resin is 5 in the coating layer.
To 90% by weight, an acrylic resin having an oxazoline group and a polyalkylene oxide chain in an amount of 5 to 90% by weight, an aliphatic wax in an amount of 0.5 to 30% by weight in the coating layer, and an average in the coating layer Particle size 0.005
An embodiment in which particles of 0.5 μm are contained in an amount of 0.1 to 20% by weight,
Polyester constituting the polyester film is polyethylene terephthalate or polyethylene-2,6-
Includes embodiments that are naphthalene dicarboxylates.

The present invention will be described in detail below.

In the present invention, the polyester constituting the polyester film is a linear saturated polyester synthesized from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative.

Specific examples of such polyesters include polyethylene terephthalate, polyethylene isophthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene-2,6-naphthalate and the like. And may be a blend of these copolymers or a small proportion thereof with another resin. Among these polyesters, polyethylene terephthalate and polyethylene-2,6-naphthalate are preferable because they have a good balance of mechanical properties and optical properties. In particular, polyethylene-2,6-naphthalate is most preferable because it is superior to polyethylene terephthalate in terms of mechanical strength, small heat shrinkage, and small amount of oligomer generated during heating.

The polyester may be a homopolymer or a copolymer obtained by copolymerizing a third component, but a homopolymer is preferable. When the polyester is polyethylene terephthalate, isophthalic acid copolymerized polyethylene terephthalate is most suitable as the copolymer. The isophthalic acid-copolymerized polyethylene terephthalate preferably has an isophthalic acid content of 5 mol% or less. The polyester may be copolymerized with a copolymerization component other than isophthalic acid or a copolymerization alcohol component in a range that does not impair the characteristics, for example, in a proportion of 3 mol% or less based on the total acid component or the total alcohol component. . Examples of the copolymeric acid component include aromatic dicarboxylic acids such as phthalic acid and 2,6-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and 1,10-decanedicarboxylic acid. Examples of the alcohol component include aliphatic diols such as 1,4-butanediol, 1,6-hexanediol and neopentyl glycol, and alicyclic diols such as 1,4-cyclohexanedimethanol. it can. These may be used alone or in combination of two or more.

When the polyester is polyethylene-2,6-naphthalenedicarboxylate, naphthalenedicarboxylic acid is used as the main dicarboxylic acid component,
Ethylene glycol is used as the main glycol component. Examples of naphthalenedicarboxylic acid include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid, and of these, 2,6-naphthalenedicarboxylic acid is preferred. The term “main” as used herein means at least 90 mol%, preferably at least 95 mol% of all repeating units in the constituent components of the polymer which is a component of the film of the present invention.

In the case of a copolymer, a compound having two ester-forming functional groups in its molecule can be used as a copolymerization component constituting the copolymer. Examples of such a compound include oxalic acid, adipic acid and phthalic acid. , Sebacic acid, dodecanedicarboxylic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, 4,
Dicarboxylic acids such as 4′-diphenyldicarboxylic acid, phenylindanedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, tetralindicarboxylic acid, decalindicarboxylic acid, diphenyletherdicarboxylic acid, p-oxybenzoic acid, p-oxyethoxybenzoic acid Such as oxycarboxylic acid, or propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane methylene glycol, neopentyl glycol, ethylene oxide adduct of bisphenol sulfone, ethylene oxide adduct of bisphenol A, diethylene glycol, polyethylene oxide glycol Such dihydric alcohols can be preferably used.

Only one of these compounds may be used,
Two or more kinds can be used. Of these, the acid component is preferably isophthalic acid, terephthalic acid,
4,4′-diphenyldicarboxylic acid, 2,7-naphthalenedicarboxylic acid and p-oxybenzoic acid, and the glycol component is trimethylene glycol, hexamethylene glycol neopentyl glycol, or an ethylene oxide adduct of bisphenol sulfone.

Polyethylene-2,6-naphthalenedicarboxylate is obtained by blocking some or all of the terminal hydroxyl groups and / or carboxyl groups with a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol. It may be present, and it may be copolymerized with a very small amount of a trifunctional or higher functional ester-forming compound such as glycerin or pentaerythritol within a range where a substantially linear polymer is obtained.

The polyester in the present invention is a conventionally known method, for example, a method of directly obtaining a low degree of polymerization polyester by the reaction of a dicarboxylic acid and glycol, or a conventionally known transesterification catalyst of a lower alkyl ester of dicarboxylic acid and glycol. , For example, by reacting with one or more compounds containing sodium, potassium, magnesium, calcium, zinc, strontium, titanium, zirconium, manganese, cobalt, the polymerization reaction in the presence of a polymerization catalyst Obtainable. As the polymerization catalyst, antimony trioxide, antimony compounds such as antimony pentoxide, germanium compounds represented by germanium dioxide, tetraethyl titanate, tetrapropyl titanate, tetraphenyl titanate or their partial hydrolysates, titanyl ammonium oxalate. Further, titanium compounds such as potassium titanyl oxalate and titanium trisacetylacetonate can be used.

When the polymerization is carried out via a transesterification reaction, trimethyl phosphate, triethyl phosphate, or triethyl phosphate for the purpose of deactivating the transesterification catalyst before the polymerization reaction.
Phosphorus compounds such as tri-n-butyl phosphate and orthophosphoric acid are usually added, but the content of the polyester in the polyethylene-2,6-naphthalenedicarboxylate as the phosphorus element is 20 to 100 ppm. It is preferable in terms of thermal stability.

The polyester may be melt-polymerized into chips, which may be further subjected to solid-state polymerization under heating under reduced pressure or in an inert gas stream such as nitrogen.

In the present invention, the polyester having an ethylene terephthalate unit or an ethylene-2,6-carboxylate unit is 90 mol% or more, preferably 95% or more, more preferably 97% or more.

The intrinsic viscosity of polyester is 0.40 dl /
It is preferably g or more, and 0.40 to 0.90 dl
/ G is more preferable. Intrinsic viscosity is 0.40d
If it is less than 1 / g, process cutting may occur frequently. On the other hand, if it is higher than 0.9 dl / g, melt extrusion becomes difficult because of high melt viscosity, and the polymerization time is long and uneconomical, which is not preferable.

The polyester film in the present invention is
It should be substantially free of particles. If particles are contained, high transparency will be impaired and the surface will be roughened.

A coating layer containing a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain is provided on at least one surface of the polyester film of the present invention.

The polyester resin used in the coating layer in the present invention is water (may contain some organic solvent).
Soluble or dispersible polyesters are preferred.

Examples of such polyester resins include polyesters obtained from the following polybasic acids or their ester-forming derivatives and polyols or their ester-forming derivatives.

Examples of the polybasic acid component of the polyester resin include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, adipic acid, sebacic acid, trimellitic acid,
Pyromellitic acid, dimer acid and 5-sodium sulfoisophthalic acid can be mentioned. It is preferable that these acid components are two or more kinds of copolyesters. still,
The polyester resin may contain an unsaturated polybasic acid component such as maleic acid or itaconic acid or a hydroxycarboxylic acid component such as P-hydroxybenzoic acid in a slight amount.

Examples of the polyol component of the polyester resin include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol,
Examples thereof include 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, poly (ethylene oxide) glycol, poly (tetramethylene oxide) glycol, and these monomers.

The acrylic resin having an oxazoline group and a polyalkylene oxide chain used in the coating layer in the present invention is
Acrylics that are soluble or dispersible in water (which may contain some organic solvent) are preferred. Examples of the acrylic resin having an oxazoline group and a polyalkylene oxide chain include those containing the following monomers as components.

The monomers having an oxazoline group include 2-vinyl-2-oxazoline and 2-vinyl-4-.
Methyl-2-oxazoline, 2-vinyl-5-methyl-
2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline may be mentioned, and one or two of these may be mentioned. Mixtures of more than one can be used. Among these, 2-isopropenyl-2-oxazoline is industrially easily available and suitable. By using the acrylic resin having an oxazoline group, the cohesive force of the coating layer is improved, and the adhesion to the hard coat or the pressure-sensitive adhesive layer becomes stronger. Further, it is possible to impart abrasion resistance to a metal roll in the film forming step or the hard coat processing step.

Examples of the monomer having a polyalkylene oxide chain include those obtained by adding polyalkylene oxide to the ester portion of acrylic acid or methacrylic acid. Examples of the polyalkylene oxide chain include polymethylene oxide, polyethylene oxide, polypropylene oxide and polybutylene oxide. The repeating unit of the polyalkylene oxide chain is 3 to 1
It is preferably 00. By using an acrylic resin having a polyalkylene oxide chain, the compatibility between the polyester resin and the acrylic resin in the coating layer becomes better than that of an acrylic resin containing no polyalkylene oxide chain, and the transparency of the coating layer is improved. You can If the number of repeating units of the polyalkylene oxide chain is less than 3, the compatibility between the polyester resin and the acrylic resin is poor and the transparency of the coating layer is poor, and if it is more than 100, the wet heat resistance of the coating layer is lowered and the high humidity, Adhesion to a hard coat or the like deteriorates at high temperatures.

Other copolymerizable components of the acrylic resin include, for example, the following monomers. That is, alkyl acrylate, alkyl methacrylate (as the alkyl group, a methyl group, an ethyl group, an n-propyl group,
(Isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.); 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, etc. A hydroxy-containing monomer; glycidyl acrylate,
Epoxy group-containing monomers such as glycidyl methacrylate and allyl glycidyl ether; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary) Monomers having a carboxyl group such as amine salt) or a salt thereof; acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N, N-dialkylacrylamide, N, N-dialkylmethacrylate (as an alkoxy group, Methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), acryloylmorpholine, N-methylol acrylamide, N-methylol methacrylamide, N-phenyl acrylamide, N-phenyl methacrylic acid Monomers having an amide group such as amide; acid anhydride monomers such as maleic anhydride and itaconic anhydride; vinyl isocyanate, allyl isocyanate, styrene, α-methylstyrene, vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxy silane, Examples include alkyl maleic acid monoester, alkyl fumaric acid monoester, alkyl itaconic acid monoester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate and butadiene.

The content of the polyester resin forming the coating layer in the coating layer is preferably 5 to 95% by weight, and particularly preferably 50 to 90% by weight. The content of the acrylic resin having an oxazoline group and a polyalkylene oxide chain forming the coating layer in the coating layer was 50.
It is preferably from 90 to 90% by weight, particularly preferably from 10 to 50% by weight. When the polyester resin content exceeds 95% by weight or the acrylic resin having an oxazoline group and a polyalkylene oxide chain is less than 5% by weight, the cohesive force of the coating layer decreases, resulting in insufficient adhesion to the hard coat or pressure-sensitive adhesive. May occur, which is not preferable. If the acrylic resin content exceeds 90% by weight, the adhesion to the polyester film may be deteriorated and the adhesion to the hard coat or the pressure-sensitive adhesive may become insufficient, which is not preferable.

Aliphatic wax is added in an amount of 0.5 to 3 in the coating layer.
The content is preferably 0% by weight, more preferably 1% by weight to 10% by weight. This ratio is 0.5
If the content is less than the weight%, the slipperiness of the film surface may not be obtained, which is not preferable. If it exceeds 30% by weight, the adhesion to a polyester film substrate and the easy adhesion to a hard coat, a pressure-sensitive adhesive or the like may be insufficient, which is not preferable.

Specific examples of the above aliphatic wax include carnauba wax, candelilla wax, rice wax,
Wood wax, jojoba oil, palm wax, rosin modified wax, auri curie wax, sugar cane wax, esbalt wax, bark wax and other plant waxes, beeswax, lanolin, whale wax, ivota wax, shellac and other animal waxes, montan Mineral waxes such as wax, ozokerite, ceresin wax, paraffin wax, microcrystalline wax, petroleum wax such as petrolactam, Fischer-Tropsch wax, polyethylene wax, polyethylene oxide wax, polypropylene wax, synthetic carbonization such as polyphenylene wax Hydrogen-based wax and the like.
Furthermore, carnauba wax, paraffin wax, and polyethylene wax are more preferable because they have good adhesiveness to a hard coat, a pressure-sensitive adhesive, and the like and have good slipperiness. In particular, an aqueous dispersion is more preferable because of environmental problems and easy handling.

The coating layer has an average particle size of 0.005 to 0.005.
It is preferable to add 0.1 to 20% by weight of the filler in the range of 0.5 μm. When the content of the filler in the coating layer is less than 0.1% by weight, the slipperiness of the film is insufficient,
It may be difficult to wind it into a roll.
If it exceeds 5% by weight, the transparency of the coating layer may be insufficient and it may not be used for display applications, which is not preferable.

Examples of the above-mentioned filler include calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide. , Inorganic fine particles such as antimony trioxide, carbon black, molybdenum disulfide, acrylic cross-linked polymer, styrene cross-linked polymer, silicone resin, fluororesin, benzoguanamine resin, phenol resin, nylon resin, polyethylene wax, etc. Can be mentioned. Of these, water-insoluble solid substances, in order to avoid settling in the aqueous dispersion,
It is preferable to select ultrafine particles having a specific gravity not exceeding 3.

The polyester film in the present invention is
The dimensional change rate at 200 ° C. under a load of 140 g / mm ^{2 in the} longitudinal direction needs to be −2 to + 2%. If it is less than -2% or more than + 2%, cracks may occur in the laminate when laminating the functional layer on the polyester film, or after laminating, or the laminate may be destroyed due to wrinkling, which is sufficient. Such functions cannot be exhibited. 140 g /
The dimensional change rate at 200 ° C. under a mm ² load is more preferably −1.5 to + 1.5%, further preferably −1 to +.
1%, particularly preferably -0.5 to + 0.5%.

The highly transparent and easily adhesive polyester film of the present invention preferably has a haze value of 1.5% or less. A more preferable haze value is 1.0% or less, and particularly preferably 0.5% or less.

The three-dimensional centerline average roughness on both sides is preferably 0.0001 to 0.02 μm, and more preferably,
0.0001 to 0.015 [mu] m, more preferably 0.
0001 to 0.010 μm. In particular, the three-dimensional centerline average roughness of at least one surface is 0.0001 to 0.005.
A thickness of μm is preferable because the surface of the functional layer when the functional layers are laminated becomes extremely flat. The most preferable surface roughness of at least one surface is 0.0005 to 0.004 μm.

The thickness of the highly transparent and easily adhesive polyester film in the present invention is preferably 1 to 500 μm, more preferably 3 to 400 μm, and further preferably 6
˜300 μm, particularly preferably 12 to 250 μm.

Next, a preferred method for producing the highly transparent and easily adhesive film of the present invention will be described. The glass transition temperature is abbreviated as Tg.

The polyester film in the present invention is
Polyester is melt extruded into a film and cooled and solidified by a casting drum to give an unstretched film. This unstretched film is stretched at Tg to (Tg + 60) ° C. in the longitudinal direction by 1
Or twice or more so that the total draw ratio becomes 3 to 6 times, and then draws at Tg to (Tg + 60) ° C. so that the draw ratio becomes 3 to 5 times, and if necessary, Tm.
It can be obtained by performing heat treatment at 180 ° C. to 255 ° C. for 1 to 60 seconds.

The composition used for coating the coating layer in the present invention is an aqueous coating solution such as an aqueous solution, an aqueous dispersion or an emulsion for forming a coating layer (hereinafter sometimes referred to as "coating"). It is preferably used in the form of In order to form a coating film, if necessary, a resin other than the above composition, for example, an antistatic agent, a colorant, a surfactant, an ultraviolet absorber or the like can be added. In particular, by adding a lubricant, the slipperiness and blocking resistance can be further improved.

The solid content concentration of the aqueous coating solution used in the present invention is
It is usually 20% by weight or less, but particularly preferably 1 to 10% by weight. When this ratio is less than 1% by weight,
The wettability to the polyester film may be insufficient, while if it exceeds 20% by weight, the stability of the coating liquid and the appearance of the coating layer may be deteriorated.

The application of the aqueous coating solution to the polyester film can be carried out at any stage, but it is preferably carried out in the production process of the polyester film, and further, the polyester film before the completion of the oriented crystallization is carried out. It is preferably applied.

Here, the polyester film before the crystal orientation is completed means an unstretched film, a uniaxially oriented film obtained by orienting the unstretched film in either the longitudinal direction or the transverse direction, and further in the longitudinal direction and the transverse direction. And a biaxially stretched film which has been stretched and oriented in two directions at a low ratio (before the biaxially stretched film is finally re-stretched in the longitudinal direction or the transverse direction to complete the oriented crystallization).

Of these, it is preferable to apply an aqueous coating solution of the above composition to an unstretched film or a uniaxially stretched film oriented in one direction, and carry out longitudinal stretching and / or transverse stretching and heat setting as it is.

When the aqueous coating solution is applied to the film, the film surface is subjected to physical treatment such as corona surface treatment, flame treatment, plasma treatment or the like as a pretreatment for improving the coating property, or it is applied together with the composition. And a chemically inactive surfactant are preferably used together.

Such a surfactant accelerates the wetting of the aqueous coating liquid on the polyester film.
Anionic and nonionic surfactants such as polyoxyethylene alkyl phenyl ether, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfate, alkyl sulfonate, alkyl sulfosuccinate, etc. Can be mentioned. The surfactant is preferably contained in the composition forming the coating film in an amount of 1 to 10% by weight.

The coating amount of the coating liquid is 0.01 to
The amount is preferably 0.3 μm, preferably 0.02 to 0.25 μm. If the thickness of the coating film is too thin, the adhesive strength will be insufficient, and conversely if it is too thick, blocking may occur or the haze value may increase.

As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brushing method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be used alone or in combination. The coating film may be formed on only one side of the film, or may be formed on both sides, as required.

[0054]

EXAMPLES The present invention will be described in more detail with reference to examples. The characteristic values in the examples were measured by the following methods.

(1) Dimensional change rate TMA / SS12 manufactured by Seiko Instruments Inc.
0C, with a load of 140 g / mm ² applied 3
The temperature was raised from 0 ° C. to 250 ° C. at a heating rate of 20 ° C./min, the dimensional change was measured, and the dimensional change rate was calculated by the following formula.

[0056]

[Equation 1]

(2) Haze Total light transmittance T according to JIS K6714-1958
t (%) and scattered light transmittance Td (%) are calculated, and haze (T
d / Tt × 100) (%) was calculated.

(3) Three-dimensional center line average roughness Non-contact type three-dimensional roughness meter (ET30HK manufactured by Kosaka Laboratory)
Using a semiconductor laser with a wavelength of 780 nm, a probe diameter of 1.6 μm, measuring length (LX) 1 mm, sampling pitch 2 μm, cutoff 0.25 mm, longitudinal magnification 100,000 times, lateral magnification 200 times , 1 scan line
When the projection profile on the film surface was measured under the condition of 00 pieces (therefore, the measurement length in the Y direction LY = 0.2 mm) and the roughness curved surface was represented by Z = F (X, Y), The value (Ra, unit nm) obtained in (1) was defined as the surface roughness of the film.

[0059]

[Equation 2]

(4) Thickness of Polyester Film Electronic Micrometer (K-312A, manufactured by Anritsu Corporation)
Film thickness was measured with a needle pressure of 30 g.

(5) Thickness of coating layer A small piece of the film is embedded in an epoxy resin (Epomount manufactured by Refinetech Co., Ltd.) and sliced to a thickness of 50 nm together with the embedded resin using Microtome 2050 manufactured by Reichert-Jung. Then, the thickness of the coating film layer was measured by observing with a transmission electron microscope (LEM-2000) at an acceleration voltage of 100 KV and a magnification of 100,000 times.

(6) Average particle size The same operation as the measurement of the coating layer thickness was carried out to measure the particle size of 100 particles, and the average value was taken as the average particle size.

(7) Adhesiveness / Hardcoat Easy adhesion Adhesive polyester film has a thickness of 10
A hard coat layer of μm is formed and cross-cut (100 squares of 1 mm ² ) is applied, and 24
Stick a cellophane tape (made by Nichiban Co., Ltd.) with a width of mm,
After peeling rapidly at a peeling angle of 180 ° C., the peeled surface was observed and evaluated according to the following criteria. 5: Peeling area is less than 10% ...... Adhesive strength is very good 4: Peeling area is 10% or more and less than 20% ...... Adhesive strength is good 3: Peeling area is 20% or more and less than 30% ...... Adhesive strength is slightly good 2: Peeling Area is 30% or more and less than 40% ...... Adhesive strength is poor 1: Peeling area is more than 40% ...... Extremely poor adhesive strength / adhesive strength (PSA) Thickness 2 on the surface of the coating layer of the easily adhesive polyester film.
Form a 0 μm PSA (PSA) layer and attach the PSA layer surface to float glass, let it stand for 1 day in an atmosphere of 23 ° C. and 65% RH, peel at a peel angle of 90 °, and stick to the glass surface. The residual state of the agent (PSA) was observed and evaluated according to the following criteria.

An adhesive (PSA: Pressure-Sensitive)
-Adhesive) was a urethane-containing acrylate copolymer (acrylic component n-butyl acrylate (86 mol%), methyl acrylate (14 mol%)). 5: Adhesive (PSA) residual area is less than 10% .... Adhesive strength is very good. 4: Adhesive (PSA) residual area is 10% or more and less than 20% ..... Adhesive strength is good. 3: Adhesive (PSA) residual area is 20% or more and less than 30% ...... Adhesive power is slightly good 2: Adhesive (PSA) residual area is 30% or more and less than 40% ...... Adhesive failure 1: Adhesive (PSA) residual area exceeds 40% ...
… Very poor adhesion

(8) Blocking resistance Two films were superposed so that the coating layer forming surface and the non-forming surface were in contact with each other, and 0.6 Kg / cm for 17 hours at 60 ° C. and 90% RH atmosphere. Apply pressure of ² ,
After that, peeling was performed, and the blocking resistance was evaluated according to the following criteria by the peeling force. ⊚: Peeling force <98 mN / 5 cm …… Very good blocking resistance ◯: 98 mN / 5 cm ≦ Peeling force <147 mN / 5 cm ...
Good blocking resistance Δ: 147 mN / 5 cm ≦ peeling force <196 mN / 5 cm
…… Slightly good blocking resistance ×: 196 mN / 5 cm ≦ peeling force …… Poor blocking resistance

(9) About 10 mg of a glass transition temperature sample was enclosed in an aluminum pan for measurement, and a differential calorimeter (DSC292 manufactured by TA instruments) was used.
0), 300 ° C from 25 ° C to 20 ° C / min
The temperature is raised to 300 ° C., kept at 300 ° C. for 5 minutes, taken out, immediately transferred onto ice, and rapidly cooled. The pan was attached to the differential calorimeter again, and the glass transition temperature (Tg: ° C) was measured by raising the temperature from -70 ° C at a rate of 10 ° C / min.

(10) Intrinsic viscosity Intrinsic viscosity ([η] dl / g) was measured with an o-chlorophenol solution at 35 ° C.

(11) Heat shrinkage rate The film sample is marked with 30 cm intervals, heat treatment is performed in an oven at a predetermined temperature without applying a load, and the mark intervals after heat treatment are measured. The heat shrinkage rate was calculated. Thermal shrinkage (%) = (distance between gauge marks before heat treatment-distance between gauge marks after heat treatment) / distance between gauge marks before heat treatment x 100

[Resin composition in coating layer and compounding ratio of each component]
Table 1 shows the composition and the compounding ratio of the coating layer used in the examples and comparative examples.

[0070]

[Table 1]

Polyester 1: 2,6-naphthalenedicarboxylic acid as acid component 70 mol% / isophthalic acid 25 mol%
/ 5-sodium sulfoisophthalic acid 5 mol%, glycol component is composed of ethylene glycol 80 mol% / diethylene glycol 20 mol% (Tg = 80
C., average molecular weight 13,000).

Polyester 1 is described in JP-A 06-11
It was manufactured as follows according to the method described in Example 1 of 6487 gazette. That is, 47 parts of dimethyl 2,6-naphthalenedicarboxylate, 13 parts of dimethyl isophthalate, 4 parts of dimethyl 5-sodiumsulfoisophthalate, 31 parts of ethylene glycol, and 5 parts of diethylene glycol were charged into a reactor, and tetrabutoxytitanium. In a nitrogen atmosphere, 05 parts was added and the temperature was controlled to 230 ° C. to heat the mixture, and the produced methanol was distilled off to carry out a transesterification reaction. Next, the temperature of the reaction system was gradually raised to 255 ° C. and the pressure inside the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain polyester 1.

Polyester 2: Acid component is terephthalic acid 6
It is composed of 0 mol% / 35 mol% isophthalic acid / 5 mol% 5-sodium sulfoisophthalic acid, and the glycol component is 80 mol% ethylene glycol / 20 mol% diethylene glycol (Tg = 40 ° C., average molecular weight 140).
00).

Incidentally, the polyester 2 is the polyester disclosed in JP-A-06-11.
It was manufactured as follows according to the method described in Example 1 of 6487 gazette. That is, 35 parts of dimethyl terephthalate, 21 parts of dimethyl isophthalate, 4 parts of 5-sodium sulfoisophthalate dimethyl, 34 parts of ethylene glycol and 6 parts of diethylene glycol were charged into a reactor, and 0.05 part of tetrabutoxytitanium was added thereto. In a nitrogen atmosphere, the temperature was controlled to 230 ° C. and heating was performed to distill off the produced methanol to carry out a transesterification reaction. Next, the temperature of the reaction system is gradually raised to 255 ° C.
Polyester 2 was obtained by performing a polycondensation reaction under reduced pressure of mmHg.

Acrylic 1: Methyl methacrylate 40 mol% / 2-isopropenyl-2-oxazoline 30 mol% / polyethylene oxide (n = 10) methacrylate 10 mol% / acrylamide 20 mol% (Tg = 50 ° C.) ).

Acrylic 1 is disclosed in JP-A-63-3716.
It manufactured as follows according to the method of manufacture example 1-3 of the gazette No. 7. That is, a four-necked flask was charged with 3 parts of sodium laurylsulfonate as a surfactant and 181 parts of ion-exchanged water and heated to 60 ° C. in a nitrogen stream, and then ammonium persulfate 0.5 part was added as a polymerization initiator.
Parts, 0.2 parts of sodium hydrogen nitrite, and further monomers 30.1 parts of methyl methacrylate, 21.9 parts of 2-isopropenyl-2-oxazoline, polyethylene oxide (n = 10) methacrylic acid. A mixture of 39.4 parts and 8.6 parts of acrylamide was added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. After the dropping was completed, the reaction was continued under stirring while maintaining the same temperature range for 2 hours, and then cooled to obtain an aqueous dispersion of acrylic 1 having a solid content of 35%.

Acrylic 2: Methyl methacrylate 40 mol% / 2-isopropenyl-2-oxazoline 40 mol% / acrylamide 20 mol% (Tg
= 80 ° C).

Acrylic 2 is described in JP-A-63-3716.
It manufactured as follows according to the method of manufacture example 1-3 of the gazette No. 7. That is, a four-necked flask was charged with 3 parts of sodium laurylsulfonate as a surfactant and 181 parts of ion-exchanged water and heated to 60 ° C. in a nitrogen stream, and then ammonium persulfate 0.5 part was added as a polymerization initiator.
Parts, 0.2 parts of sodium hydrogen nitrite, and then a mixture of 44.4 parts of methyl methacrylate, 43.0 parts of 2-isopropenyl-2-oxazoline, and 12.6 parts of acrylamide, which are monomers. Liquid temperature is 6 over time
The mixture was added dropwise while adjusting to 0 to 70 ° C. After the dropping was completed, the reaction was continued under stirring while maintaining the same temperature range for 2 hours, and then cooled to obtain an aqueous dispersion of acrylic 2 having a solid content of 35%.

Acrylic 3: 10 mol% of methyl methacrylate / 80 mol% of ethyl acrylate / N-
Acrylic copolymer of 10 mol% methylol acrylamide (Tg = -5 ° C).

Acrylic 3 is disclosed in JP-A-63-3716.
It manufactured as follows according to the method of manufacture example 1-3 of the gazette No. 7. That is, a four-necked flask was charged with 3 parts of sodium laurylsulfonate as a surfactant and 181 parts of ion-exchanged water and heated to 60 ° C. in a nitrogen stream, and then ammonium persulfate 0.5 part was added as a polymerization initiator.
Parts, 0.2 parts of sodium hydrogen nitrite, and a mixture of monomers, 10.1 parts of methyl methacrylate, 81.1 parts of ethyl acrylate and 8.8 parts of N-methylol acrylamide for 3 hours. , The liquid temperature is 60-70
It was added dropwise while adjusting the temperature to be ° C. After the dropping, the reaction is continued under stirring while maintaining the same temperature range for 2 hours.
Then, it was cooled to obtain an aqueous dispersion of acrylic 3 having a solid content of 35%.

Additive 1: Silica filler (average particle size: 1
00nm) (Nissan Chemical Co., Ltd. trade name Snowtex ZL) Additive 2: Carnauba wax (Chukyo Yushi Co., Ltd. trade name Cerosol 524) Wetting agent: polyoxyethylene (n = 7) lauryl ether (Sanyo Chemical Co., Ltd.) Product name Naloacty N-7
0)

[Example 1] 100 parts of dimethyl naphthalene-2,6-dicarboxylate and ethylene glycol 6
Using 0 part of 0.03 part of manganese acetate tetrahydrate as a transesterification catalyst, the transesterification reaction was carried out for 120 minutes while gradually raising the temperature from 150 ° C to 238 ° C.
When the reaction temperature reached 170 ° C on the way, 0.024 part of antimony trioxide was added, and after the transesterification reaction was completed, trimethyl phosphate (135 ° C in ethylene glycol,
A solution heat-treated under a pressure of 0.11 to 0.16 MPa for a time period: 0.023 part in terms of trimethyl phosphate) was added. After that, the reaction product was transferred to a polymerization reactor and heated at 290 ° C.
Polyethylene-2,6-naphthalenedicarboxylate having an intrinsic viscosity of 0.61 dl / g and substantially no particles is obtained by conducting a polycondensation reaction under a high vacuum of 27 Pa or less. It was

The pellets of polyethylene-2,6-naphthalenedicarboxylate were dried at 170 ° C. for 6 hours, then fed to an extruder hopper and melted at a melting temperature of 305 ° C., a stainless steel fine wire filter having an average opening of 17 μm. Filtered through a 3 mm slit die, extruded on a rotary cooling drum having a surface temperature of 60 ° C., and rapidly cooled to obtain an unstretched film. The unstretched film thus obtained was preheated at 120 ° C., further heated by an IR heater at 900 ° C. from 15 mm above between low speed and high speed rolls and stretched 3.0 times in the machine direction. On one side of this longitudinally stretched film, the thickness of the coating film after drying the above coating agent 1 was 0.1 μm.
Was coated with a roll coater so that

Subsequently, it was supplied to a tenter and stretched 3.1 times in the transverse direction at 145 ° C. The resulting biaxially oriented film was heat set at a temperature of 240 ° C. for 5 seconds to obtain a highly transparent polyester film having a thickness of 75 μm. The characteristics of the obtained film are shown in Table 2.

[0085]

[Table 2]

[Examples 2 to 4] High transparency was obtained in the same manner as in Example 1 except that the stretching ratio of the film, the heat setting temperature, the composition and thickness of the coating layer, and the final thickness of the film were as shown in Table 2. An easily adhesive polyester film was obtained. The characteristics of the obtained film are shown in Table 2.

Example 5 Dimethyl terephthalate 96
Parts, ethylene glycol 58 parts, manganese acetate 0.03
8 parts and antimony trioxide (0.041 parts) were charged into the respective reactors, the transesterification reaction was carried out while distilling methanol until the internal temperature reached 240 ° C. under stirring, and after the transesterification reaction was completed, trimethyl phosphate 0 .0
97 parts were added. Subsequently, the temperature of the reaction product is raised,
Finally, polycondensation was performed under a high vacuum at 280 ° C. to obtain substantially particle-free polyethylene terephthalate having an intrinsic viscosity ([η]) of 0.64.

Next, the polyethylene terephthalate chips were dried at 170 ° C. for 3 hours, melt-extruded at 290 ° C., and rapidly cooled and solidified on a cooling drum kept at 20 ° C. to obtain an unstretched film. The unstretched film was stretched 3.3 times in the longitudinal direction at 95 ° C., and then the coating material 1 was applied to one side by a roll coater so that the thickness after drying was 0.10 μm, and the film was stretched in the lateral direction at 110 ° C. After stretching 3.5 times, it was heat-treated at 235 ° C. to obtain a biaxially stretched film having a thickness of 125 μm. The characteristics of the obtained film are shown in Table 2.

Comparative Example 1 Polyethylene-2,6-naphthalenedicarboxylate used in Example 1 was kneaded with 0.1% by weight of spherical silica particles having an average particle size of 0.35 μm to prepare This was dried, extruded and longitudinally stretched in the same manner as in Example 1. Then, a biaxially oriented polyester film having a thickness of 75 μm was obtained in the same manner as in Example 1 except that the coating liquid composition was the above coating liquid 5.

Since the obtained film contains particles, the haze is high and the surface is rough, and since the composition of the coating layer is out of the range of the present invention, the adhesion with the adhesive layer is low. It was bad.

Comparative Example 2 A biaxially oriented film having a thickness of 75 μm was obtained in the same manner as in Example 1 except that the draw ratio, heat setting temperature and coating layer composition were changed as shown in Table 2. The characteristics of the obtained film are shown in Table 2. The dimensional change rate is large,
Moreover, it was inferior in adhesiveness to the adhesive and blocking resistance.

[Comparative Example 3] The composition of the coating film layer was changed to coating liquid 7 in Table 1.
A biaxially oriented film was obtained in the same manner as in Example 1 except that The obtained film was inferior in adhesiveness to the adhesive.

[0093]

EFFECTS OF THE INVENTION According to the present invention, it has excellent transparency, surface flatness, easy adhesion and processability, and is particularly suitable for organic electroluminescence (organic EL) devices, electronic paper, and solar cells. A film useful as a substrate film can be obtained.

Continued front page    (72) Inventor Hiroshi Kusunome             3-37-19 Oyama, Sagamihara City, Kanagawa Prefecture             People DuPont Films Co., Ltd. Sagamihara Research Center             In the center (72) Inventor Shinji Yano             3-37-19 Oyama, Sagamihara City, Kanagawa Prefecture             People DuPont Films Co., Ltd. Sagamihara Research Center             In the center (72) Inventor Koji Kubo             3-37-19 Oyama, Sagamihara City, Kanagawa Prefecture             People DuPont Films Co., Ltd. Sagamihara Research Center             In the center F-term (reference) 2H042 BA02 BA20                 2K009 AA15 BB14 BB24 CC24 DD02                       EE00                 4F006 AA35 AB24 AB35 BA01 CA05                       DA00                 4F100 AJ11B AJ11C AK25B AK25C                       AK41A AK41B AK41C AK42A                       AK54B AK54C AL01B AL01C                       AL05B AL05C BA02 BA03                       BA06 BA07 BA10B BA10C                       DE01A DE01B DE01C EH17                       EH172 EH46 EH462 EJ38                       EJ382 EJ50 EJ502 GB15                       GB41 JK14 JK14A JK14B                       JK14C JL11 JM02B JM02C                       JN01 YY00A YY00B YY00C

Claims (6)

[Claims] 1. A highly transparent and easily-adhesive polyester film comprising a polyester film containing substantially no particles and having a coating layer containing a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain provided on at least one surface of the polyester film. The dimensional change rate at 200 ° C. under a load of 140 g / mm ^{2 in} the longitudinal direction of the film is −
2 to + 2%, a highly transparent and easily adhesive polyester film. 2. A polyester film having a haze value of 1.
It is 5% or less, and the three-dimensional center line average roughness of the film surface is 0.0001 to 0.02 μm on both surfaces.
The highly transparent and easily adhesive polyester film described. 3. A polyester resin in an amount of 5 to 90 in the coating layer.
The highly transparent and easily adhesive polyester film according to claim 1 or 2, wherein the acrylic resin having an oxazoline group and a polyalkylene oxide chain is contained in an amount of 5 to 90% by weight. 4. An aliphatic wax is contained in the coating layer in an amount of 0.5-3.
The highly transparent and easily adhesive polyester film according to any one of claims 1 to 3, which is contained in an amount of 0% by weight. 5. An average particle size of 0.005 to 0.
The particles of 5 μm are contained in an amount of 0.1 to 20% by weight.
4. A highly transparent and easily adhesive polyester film as described in 4 above. 6. The highly transparent and easily adhesive polyester film according to claim 1, wherein the polyester constituting the polyester film is polyethylene terephthalate or polyethylene-2,6-naphthalene dicarboxylate.