JP2003291290A - Optical easy-to-adhere polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester film which is excellent in transparency, easy slippage and scuff resistance, suitable for the optical use and excellent in the adhesion to other layers. <P>SOLUTION: In this optical easy-to-adhere polyester film, a coating layer is provided at least on one surface of the polyester film. The coating layer contains a polymer resin and also particulates having an average particle diameter of 80-120 nm, particulates having an average particle diameter of 50-70 nm and particulates having an average particle diameter of 20-40 nm. Each particulate is an inorganic or organic particulate. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical easy-adhesive polyester film, and more specifically, to an optical easy-adhesive polyester film having an easy-adhesive coating film of a specific composition formed on at least one surface of the polyester film. Regarding 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 raw material for films for electronic parts, films for electronic parts, films for electrical insulation, films for laminating metal plates, 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. Further, excellent adhesion to the prism lens layer, hard coat, adhesive, antireflection treatment, sputter layer, etc. is required.

Since the optical base material film is required to have transparency, it is usually necessary to minimize the amount of the internally added filler.
Further, in order to improve the adhesive strength of the easy-adhesion layer, a resin having a low glass transition point is used for the easy-adhesion layer. In this way, the optical film has a flat surface because there is no minimum internal filler or no internal filler, and when the resin with a low glass transition point is used for the easy-adhesion layer, the film is wound, There is a problem that sticking occurs at the time of stacking, the films do not slide and the handling property deteriorates, and since the films do not slip easily, the surface is likely to be scratched during film formation or processing.

On the other hand, a biaxially oriented polyester film generally has poor adhesion to other materials such as a prism lens layer containing an acrylic resin as a main component and a hard coat. It has been proposed to stack and use an easy-adhesion layer such as an acrylic resin or a urethane resin (for example, JP-A-10-1).
19215 and JP 2000-246855). However, the adhesive force may be insufficient in the case where the easily adhesive layer made of these resins is formed. For example, CR
The film for T has good adhesion to the hard coat layer, but insufficient adhesion to the adhesive layer on the opposite side, and is poor in versatility.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art, is excellent in transparency, slipperiness and scratch resistance, and is suitably used for optical applications and has an adhesive force with other layers. It is an object of the present invention to provide an excellent polyester film.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a polymer resin and an average particle size of 80 to 120 nm and 50 to 50 nm are provided on at least one surface of a polyester film. The inventors have found that the problem can be solved by forming an easily-adhesive coating film containing inorganic or organic fine particles of 70 nm and 20 to 40 nm, and have completed the present invention.

That is, in the present invention, a coating layer is provided on at least one surface of a polyester film, and the coating layer is a polymer resin and fine particles having an average particle diameter of 80 to 120 nm, fine particles having an average particle diameter of 50 to 70 nm, and an average particle diameter. It is an optically adhesive polyester film containing fine particles of 20 to 40 nm, each fine particle being an inorganic fine particle or an organic fine particle.

In a preferred embodiment of the present invention, (item 2)
The polymer resin of the coating layer has a glass transition temperature of 40 to 100 ° C.
(Item 3), the polymer resin of the coating layer is an acrylic resin having an oxazoline group and a polyalkylene oxide chain, and (Item 4) the coating layer further has an aliphatic wax of 0.5 to 30. Aspects containing wt%, (Claim 5) haze value is 1.5% or less, and the center line average roughness (Ra) of the coating layer surface is 0.002 to 0.01.
In the range of μm, the friction coefficient (μs) of the coating layer surface is 0.8 or less, and (Claim 6) the polyester constituting the polyester film is polyethylene terephthalate or polyethylene-2,6-naphthalate. Include.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

[Polyester Film] 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, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), and polyethylene-2,6-naphthalate.

The polyester used for the polyester film may be a copolymer of the above polyesters, and the above polyesters are mainly used (for example, 80 mol%).
The above components may be blended with a small proportion (for example, 20 mol% or less) of another type of resin. Polyethylene terephthalate or polyethylene-2,6-naphthalate is particularly preferable as the polyester because it has a good balance of mechanical properties and optical properties.

The polyester may also contain colorants, antistatic agents, antioxidants, organic lubricants and catalysts.

In the present invention, the polyester film preferably contains no filler in terms of transparency.

The polyester film is obtained by, for example, melt-extruding the above polyester into a film and cooling and solidifying it by a casting drum to obtain an unstretched film. This unstretched film is once or twice in the longitudinal direction at Tg to (Tg + 60) ° C. Stretching is performed so that the total magnification is 3 to 6 times, and then stretching is performed at Tg to (Tg + 60) ° C. in the width direction so that the magnification is 3 to 5 times, and further 180 times if necessary.
It can be obtained by performing heat treatment at ˜230 ° C. for 1 to 60 seconds and performing reheat treatment at a temperature 10 ° C. to 20 ° C. lower than the heat treatment temperature while shrinking 0 to 20% in the width direction. The glass transition temperature is abbreviated as Tg.

The thickness of the polyester film is 25 to 300 μm in order to obtain the strength required when it is used as a support for liquid crystal, hard coat, touch panel, antiglare treatment, electromagnetic wave shielding film for PDP, organic EL and the like. Is preferable, and particularly preferably 50 to 250 μm.

[Coating layer] In the present invention, a coating layer is provided on at least one surface of the polyester film, and the coating layer is a polymer resin and fine particles having an average particle diameter of 80 to 120 nm, and fine particles having an average particle diameter of 50 to 70 nm. And fine particles having an average particle diameter of 20 to 40 nm, and each fine particle is an inorganic fine particle or an organic fine particle.

[Polymer Resin] The polymer resin of the coating layer is preferably soluble or dispersible in water (which may contain some organic solvent) and has a glass transition temperature of 4
A polyester resin in the range of 0 to 100 ° C., an acrylic resin having an oxazoline group and a polyalkylene oxide chain are preferable, and it is particularly preferable to use these in combination.

Examples of the polyester resin having a glass transition temperature in the range of 40 to 100 ° C. include the following polyesters obtained from polybasic acids or their ester-forming derivatives and polyols or their ester-forming derivatives.

As the polyester resin, a polyester obtained from the following polybasic acid component and diol component can be used. That is, as the polyvalent base component, for example, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, Pyromellitic acid, dimer acid, and 5-sodium sulfoisophthalic acid can be exemplified. As the polyester resin that constitutes the polymer binder,
It is preferable to use a copolyester using two or more dicarboxylic acid components. 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.

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

The glass transition temperature of polyester resin is 40
To 100 ° C, more preferably 60 to 80 ° C. Within this range, excellent adhesiveness and excellent scratch resistance can be obtained. On the other hand, if the glass transition temperature is less than 40 ° C., blocking easily occurs between the films, and 10
If it exceeds 0 ° C, the coating film becomes hard and brittle, and the scratch resistance deteriorates, which is not preferable.

As the acrylic resin having an oxazoline group and a polyalkylene oxide chain, for example, an acrylic resin made of a monomer having an oxazoline group and a monomer having a polyalkylene oxide chain as shown below can be used.

The monomers having an oxazoline group include 2-vinyl-2-oxazoline and 2-vinyl-4-.
Methyl-2-oxazoline, 2-vinyl-5-methyl-
Examples thereof include 2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-methyl-2-oxazoline. These 1 type, or 2 or more types of mixture can be used. Among these, 2
-Isopropenyl-2-oxazoline is industrially easily available and suitable. By using an acrylic resin having an oxazoline group, the cohesive force of the coating layer is improved, and the adhesion with the hard coat, the pressure-sensitive adhesive layer or the like becomes stronger. Furthermore,
It is possible to impart abrasion resistance to a metal roll in a film forming step or a 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 preferably 3 to 100. By using an acrylic resin with a polyalkylene oxide chain, the compatibility of the polyester resin of the polymer binder of the coating layer with the acrylic resin is better than that of an acrylic resin that does not contain a polyalkylene oxide chain, and the transparency of the coating layer is improved. Can be improved. When 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 when it is more than 100, the wet heat resistance of the coating layer is lowered and the humidity and the temperature are high. Therefore, the adhesion to a hard coat or the like is deteriorated, which is not preferable.

The acrylic resin may be copolymerized with other monomers, for example, the monomers exemplified below. That is, alkyl acrylate, alkyl methacrylate (as the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group,
Isobutyl group, t-butyl group, 2-ethylhexyl group,
Cyclohexyl group); hydroxy-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate; epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether; Having a carboxy group or its salt such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.) Monomer; acrylamide, methacrylamide, N-alkyl acrylamide, N-alkyl methacrylamide, N,
N-dialkyl acrylamide, N, N-dialkyl methacrylate (as the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group,
Isobutyl group, t-butyl group, 2-ethylhexyl group,
Cyclohexyl group, etc.), N-alkoxyacrylamide, N-alkoxymethacrylamide, N, N-dialkoxyacrylamide, N, N-dialkoxymethacrylamide (as the alkoxy group, methoxy group, ethoxy group, butoxy group, isobutoxy group, etc. ), Acryloylmorpholine, N-methylolacrylamide, N-methylolmethacrylamide, N-phenylacrylamide, N-phenylmethacrylamide, or other amide group-containing monomers; maleic anhydride, itaconic anhydride, or other acid anhydride monomers; vinyl. Isocyanate, allyl isocyanate, styrene, α-methylstyrene, vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester Le, alkyl itaconic acid monoester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate, butadiene.

The content ratio of the polyester resin constituting the polymer binder of the coating layer in the coating layer is preferably 5
˜95% by weight, more preferably 50 to 90% by weight.

The content of the acrylic resin having an oxazoline group and a polyalkylene oxide chain constituting the polymer binder of the coating layer in the coating layer is preferably 5 to 9.
It is 5% by weight, more preferably 5 to 90% by weight, and particularly preferably 10 to 50% by weight.

If the polyester resin content exceeds 95% by weight, or if 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, and adhesion to a hard coat or a pressure-sensitive adhesive is reduced. It is not preferable because the property may be insufficient. Acrylic resin 9
If it exceeds 5% by weight, the adhesion to the polyester film may be deteriorated and the adhesion to the hard coat or the pressure-sensitive adhesive may be insufficient.

[Fine Particles] The fine particles constituting the coating layer in the present invention include fine particles having an average particle diameter of 80 to 120 nm, fine particles having an average particle diameter of 50 to 70 nm, and average particle diameter of 20 to 40 nm.
Fine particles, and each fine particle is an inorganic fine particle or an organic fine particle. In the present invention, the coating film contains the above three types of fine particles.

Each fine particle is preferably contained in the coating film in the following content ratio as a weight ratio to the coating film.

The fine particles having an average particle size of 80 to 120 nm are preferably contained in the range of 0.05 to 5% by weight, and the film can be provided with lubricity within this range. 1 to 1 for fine particles having an average particle diameter of 50 to 70 nm
It is preferably contained in the range of 0% by weight, and in this range, the winding property can be improved. Fine particles having an average particle diameter of 20 to 40 nm are preferably contained in the range of 1 to 10% by weight, and in this range, scratch resistance can be mainly improved.

When inorganic fine particles are used as the fine particles, examples of the inorganic fine particles include calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide,
Examples thereof include iron oxide, zirconium oxide, barium sulfate, titanium oxide, tin oxide, antimony trioxide, carbon black and molybdenum disulfide.

When organic fine particles are used as the fine particles, examples of the organic fine particles include organic fine particles such as acrylic cross-linked polymer, styrene cross-linked polymer, silicone resin, fluororesin, benzoguanamine resin, phenol resin and nylon resin. You can Of these, it is preferable to select fine particles having a specific gravity of not more than 3 in order to prevent the water-insoluble solid substance from settling in the aqueous dispersion.

[Aliphatic Wax] The coating layer preferably contains an aliphatic wax, and the content is preferably 0.5 to 30% by weight, more preferably 1% to 10% by weight.
% By weight. If the content is less than 0.5% by 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 aliphatic wax include plant waxes such as carnauba wax, candelilla wax, rice wax, wax, jojoba oil, palm wax, rosin modified wax, auri curly wax, sugar cane wax, esparto wax, and bark wax. , Beeswax, lanolin, whale wax,
Animal waxes such as Ibotaro and shellac wax, mineral waxes such as montan wax, ozokerite and ceresin wax, petroleum waxes such as paraffin wax, microcrystalline wax and petrolactam,
Examples thereof include synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene wax, oxidized polyethylene wax, polypropylene wax and oxidized polypropylene wax. Among them, carnauba wax, paraffin wax, and polyethylene wax are particularly preferable because they are easily adhered to a hard coat, a pressure-sensitive adhesive or the like and have good lubricity. It is preferable to use these as an aqueous dispersion because they can reduce the environmental load and are easy to handle.

[Production Method] The above composition used for coating the coating layer in the present invention is 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 an aqueous coating solution such as. In order to form a coating film, a resin other than the above composition, for example, an antistatic agent, a colorant, a surfactant, an ultraviolet absorber, a cross-linking agent or the like can be added, if necessary.

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, which is not preferable.

The application of the aqueous coating liquid to the polyester film can be carried out at any stage, but it is preferably carried out during 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). Among them, unstretched film or uniaxially stretched film oriented in one direction,
It is preferable to apply an aqueous coating solution of the above composition, and then carry out longitudinal stretching and / or transverse stretching and heat setting as it is.

When the aqueous coating liquid 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 coatability, or it is applied together with the composition. And a chemically inactive surfactant are preferably used together. Such a surfactant has a function of promoting the wetting of the aqueous coating liquid on the polyester film and improving the stability of the coating liquid, and examples thereof include polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, and fatty acid metal. Examples thereof include anionic and nonionic surfactants such as soaps, alkyl sulfates, alkyl sulfonates and alkyl sulfosuccinates. 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 0.01
The amount is preferably 0.3 μm, preferably 0.02 to 0.25 μm. If the coating film is too thin, the adhesive strength will be insufficient, and if it is too thick, blocking may occur or the haze value may increase, which is not preferable.

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, if necessary.

[Physical Properties] The optically easy-adhesive polyester film of the present invention has a haze value of 1.5% or less and a center line average roughness (Ra) of the coating layer surface in the range of 0.002 to 0.01 μm. The friction coefficient (μs) on the surface of the coating layer is preferably 0.8 or less. Such an optically easy-adhesive polyester film can be obtained by forming a coating layer made of the above composition.

[0044]

EXAMPLES The present invention will be described in more detail with reference to examples. Various physical properties were evaluated by the following methods.

(1) Scratch resistance A hard chrome-plated pin having a diameter of 6 mm was fixed, and a film cut to 20 cm in the longitudinal direction and 15 mm in the width direction was brought into contact with the pin at 90 ° and a constant speed (20 m
The scratches entering the film surface were evaluated by sliding on the pin at m / s). 5: No scratches at all 4: 0% <Scratch area to the entire area ≤ 10% 3: 10% <Scratch area to the entire area ≤ 25% 2: 25% <Scratch area to the entire area ≤ 50% 1 : 50% <Scratch area to the total area

(2) Haze value According to JIS K7136, the haze value of the film was measured using a haze measuring instrument (NDH-2000) manufactured by Nippon Denshoku Industries Co., Ltd. The haze of the film was evaluated according to the following criteria. ⊚: Haze value ≦ 1.0% …… Film haze is extremely good ◯: 1.0% <haze value ≦ 1.5% …… Film haze is good ×: 1.5% <haze value …… Film haze Bad

(3) Center line average surface roughness (Ra) According to JIS B0601, a needle radius of 2 was obtained using a high precision surface roughness meter SE-3FAT manufactured by Kosaka Laboratory Ltd.
Draw a chart under the conditions of μm, load of 30 mg, magnification of 200,000 times and cutoff of 0.08 mm, and extract a portion of measurement length L from the surface roughness curve in the direction of its center line.
When the roughness curve is represented by Y = f (x) with the center line of the extracted portion as the X axis and the direction of longitudinal magnification and the Y axis, the value given by the following equation is represented in nm. Further, in this measurement, four pieces were measured with a reference length of 1.25 mm and expressed as an average value.

[0048]

[Equation 1]

(4) Friction coefficient (μs) According to ASTM D1894-63, using a slippery measuring instrument manufactured by Toyo Tester Co., Ltd., a coefficient of static friction between a coating film-formed surface and a polyethylene terephthalate film (non-coated surface). (Μs) was measured. However, the thread plate was a glass plate and the load was 1 kg. The slip property of the film was evaluated according to the following criteria. ⊚: Friction coefficient (μs) ≦ 0.5 …… very good sliding property ○: 0.5 <friction coefficient (μs) ≦ 0.8 …… good sliding property ×: 0.8 <friction coefficient (μs) …… Poor slipperiness

(5) Adhesiveness / Hard coat 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 °, 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 (PSA) Thickness 20 on the coating film forming surface of the easily adhesive polyester film
Form a pressure-sensitive adhesive (PSA) layer of μm, and stick the pressure-sensitive adhesive layer surface on the float glass.
The film was aged for a day and peeled at a peeling angle of 90 °, and the state of the PSA (PSA) remaining on the glass surface was observed and evaluated according to the following criteria.

An adhesive (PSA: Pressure-Sensiti
For the ve-Adhesive), a urethane-containing acrylate copolymer (acrylic components are n-butyl acrylate (86 mol%) and methyl acrylate (14 mol%)) was used. 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 3: Adhesive (PSA) residual area is. 20% or more and less than 30% ...... Adhesive strength is slightly good 2: Adhesive (PSA) residual area is 30% or more and less than 40% ...... Adhesive failure 1: Adhesive (PSA) residual area is more than 40% ...... Very poor adhesion

(6) Blocking resistance Two films were superposed on each other so that the coating film-forming surfaces were in contact with each other, and the films were subjected to 0.6 kg / cm ² at 60 ° C. and 80% RH for 17 hours. A pressure was applied, and then peeling was performed, and blocking resistance was evaluated by 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

(7) About 10 mg of a glass transition temperature sample was enclosed in an aluminum pan for measurement, and a differential calorimeter (V4.OB2000 manufactured by DuPont) was used.
Type DSC), 3 at a speed of 25 ° C to 20 ° C / min
The temperature was raised to 00 ° C., and the temperature was kept at 300 ° C. for 5 minutes, then 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 increasing the temperature from 25 ° C at a rate of 20 ° C / min.

(8) Intrinsic viscosity Intrinsic viscosity ([η] dl / g) was measured with an o-chlorophenol solution at 25 ° C.

(9) Comprehensive Evaluation Evaluation was carried out according to the following criteria. A: Scratch resistance is 5 and surface roughness (Ra) is 0.002 to 0.
It is within the range of 01 μm, the adhesion to the hard coat and the pressure-sensitive adhesive is both 3 or more, and the evaluations of haze, friction coefficient, and blocking resistance are all ⊚ (comprehensive evaluation: extremely good) ◯: Scratch resistance is 4 The surface roughness (Ra) is 0.002 to above.
It is in the range of 0.01 μm, the adhesion to the hard coat and the pressure-sensitive adhesive is both 3 or more, and haze, friction coefficient, and blocking resistance are evaluated as ○, and Δ and × are not present (total evaluation. Good) Δ: Scratch resistance is 3 or more and surface roughness (Ra) is 0.002
It is in the range of 0.01 μm, the adhesion to the hard coat and the adhesive is both 3 or more, and there is Δ in the evaluation of haze, coefficient of friction, and blocking resistance, and x does not exist (comprehensive evaluation: somewhat good). X: Scratch resistance is 2 or less, or surface roughness (Ra) is 0.
It is out of the range of 002 to 0.01 μm, the adhesiveness to the hard coat and the adhesive is 2 or less, or x is 1 or more in the evaluation of haze, friction coefficient, and blocking resistance (total evaluation.・ Bad)

[Examples 1 and 2 and Comparative Examples 1 and 2] Molten polyethylene terephthalate ([η] = 0.62dl /
g, Tg = 78 ° C.) is extruded from a die, cooled by a cooling drum by a conventional method to obtain an unstretched film, and then stretched 3.2 times in the machine direction, and then the coating material (coating shown in Table 2) is applied to both surfaces thereof. The compositions of Liquids 1 to 6 are the coating composition shown in Table 1 below.
An aqueous coating solution having a concentration of 8% was uniformly applied with a roll coater.

[0057]

[Table 1]

The coated film is then continued for 9
Dry at 5 ° C and stretch laterally at 120 ° C 3.5 times,
Shrink 3% in the width direction at 220 ° C and heat set to a thickness of 125
An easily adhesive film having a thickness of μm was obtained. The thickness of the coating film was 0.1 μm. The evaluation results are shown in Table 2.

[0059]

[Table 2]

Polyester: Acid component is 70 mol% of 2,6-naphthalenedicarboxylic acid / 25 mol% of isophthalic acid /
5-sodium sulfoisophthalic acid 5 mol%, glycol component is composed of ethylene glycol 90 mol% / diethylene glycol 10 mol% (Tg = 85 ℃,
Average molecular weight 12500). The polyester was produced as follows according to the method described in Example 1 of JP-A 06-116487. That is, 47 parts of dimethyl 2,6-naphthalenedicarboxylate and 1 part of dimethyl isophthalate.
3 parts, dimethyl 4-sodium sulfoisophthalate 4
Part, ethylene glycol 33 parts, and diethylene glycol 3 parts were charged to a reactor, and 0.05 part of tetrabutoxytitanium was added to the reactor and heated under a nitrogen atmosphere while controlling the temperature to 230 ° C. to distill off the produced methanol. Then, transesterification reaction was carried out. Then, 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 a polyester.

Acrylic: 30 mol% methyl methacrylate / 2-isopropenyl-2-oxazoline 30 mol%
/ Polyethylene oxide (n = 10) methacrylate 1
It is composed of 0 mol% / 30 mol% acrylamide (Tg = 50 ° C.). Acrylics are disclosed in JP-A-63-3
It manufactured as follows according to the method of the manufacture examples 1-3 of 7167 gazette. That is, a four-necked flask was charged with 302 parts of ion-exchanged water, heated to 60 ° C. in a nitrogen stream, and then ammonium persulfate 0.5 was added as a polymerization initiator.
Parts, 0.2 parts of sodium hydrogen nitrite are further added, and 23.3 parts of monomers, methyl methacrylate, 22.6 parts of 2-isopropenyl-2-oxazoline, polyethylene oxide (n = 10) methacrylic acid are added. A mixture of 40.7 parts and 13.3 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 acrylic aqueous dispersion having a solid content of 25%.

Fine particles 1: Acrylic filler (average particle size:
100 nm) (Nippon Shokubai Co., Ltd. trade name Eposter MX-100W) Fine particles 2: Silica filler (average particle size: 60 nm) (Nissan Chemical Co., Ltd. trade name Snowtex) Fine particles 3: Silica filler (average particle size: 30 nm) (Nissan Chemical Co., Ltd. product name Snowtex) Additive: Carnauba wax (Chukyo Yushi Co., Ltd. product name Cerozole 524) Wetting agent: Polyoxyethylene (n = 7) lauryl ether (Sanyo Chemical Co., Ltd. product name Naloacty N-7
0)

[Example 3] Molten polyethylene-2,6-
Naphthalate ([η] = 0.65dl / g, Tg = 12
(1 ° C.) is extruded from a die, cooled by a cooling drum by a conventional method to give an unstretched film, and then stretched by 3.6 times in the machine direction. An aqueous coating solution having a concentration of 8%) was uniformly applied with a roll coater. The coated film is then subsequently dried at 105 ° C. and stretched transversely at 140 ° C. by a factor of 3.8,
The film was shrunk by 3% in the width direction at 0 ° C. and heat-fixed to obtain an easily-adhesive film having a thickness of 188 μm. The thickness of the coating film is 0.15
was μm. The evaluation results are shown in Table 2.

[0064]

EFFECT OF THE INVENTION According to the present invention, an easily adhesive polyester film for optics, which is excellent in transparency, slipperiness and scratch resistance, is suitably used for optical applications, and has excellent adhesive strength with other layers is provided. can do. INDUSTRIAL APPLICABILITY The film of the present invention is particularly useful for various optical applications, especially as a base film for prism lens sheets, touch panels, backlights, etc., a base film for antireflection films, and an explosion-proof base film for displays.

   ─────────────────────────────────────────────────── ─── Continued front page    (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) 4F100 AA01B AA01C AK01B AK01C                       AK25B AK25C AK41A AK41B                       AK41C AK42A AK42B AK42C                       BA02 BA03 BA06 BA07 BA10B                       BA10C DE01B DE01C GB41                       JA05B JA05C JK14B JK14C                       JK16B JK16C JL11 JN01                       YY00B YY00C                 4J038 BA212 CG141 CH141 CR071                       DD041 DF022 GA02 GA08                       KA20 MA08 MA09 MA10 MA13                       MA14 NA01 NA11 NA12 PB08

Claims (6)

[Claims] 1. A coating layer is provided on at least one side of a polyester film, and the coating layer comprises a polymer resin, fine particles having an average particle diameter of 80 to 120 nm, and an average particle diameter of 50 to 50.
An easily adhering polyester film for optics, which contains fine particles of 70 nm and fine particles having an average particle diameter of 20 to 40 nm, each fine particle being an inorganic fine particle or an organic fine particle. 2. The easily adhesive polyester film for optics according to claim 1, wherein the polymer resin of the coating layer is a polyester resin having a glass transition temperature of 40 to 100 ° C. 3. The easily adhesive polyester film for optics according to claim 1, wherein the polymer resin of the coating layer is an acrylic resin having an oxazoline group and a polyalkylene oxide chain. 4. The coating layer further comprises an aliphatic wax 0.5 to
The easily adhesive polyester film for optics according to any one of claims 1 to 3, which contains 30% by weight. 5. The haze value is 1.5% or less, and the center line average roughness (Ra) of the coating layer surface is 0.002 to 0.01.
The optical adhesion polyester film according to any one of claims 1 to 4, which has a friction coefficient (μs) of 0.8 or less in the range of μm. 6. The easily adhesive polyester film for optics according to claim 1, wherein the polyester constituting the polyester film is polyethylene terephthalate or polyethylene-2,6-naphthalate.