JP2009126042A - Easy adhesive film for optics - Google Patents

Abstract

Provided is an easily adhesive film for optics that has transparency and adhesiveness suitable as a base film for an optical member and in which sticking between films is suppressed.
SOLUTION: A polyester film and an easy-adhesion layer comprising a copolyester provided on at least one surface thereof, and the copolyester of the easy-adhesion layer has a specific dihydroxy compound in which 20 to 80 mol% of a diol component is a specific dihydroxy compound. An easily adhesive optical film, characterized in that 20 to 80 mol% is occupied by ethylene glycol.
[Selection figure] None

Description

  The present invention relates to an easily adhesive film for optics used as a base film for optical members.

In recent years, polyester films have been widely used as optical members for plasma displays (hereinafter sometimes referred to as “PDP”) and liquid crystal displays (hereinafter sometimes referred to as “LCD”). It is used as a prism lens sheet, a reflector, a base film for an antireflection film, and a base film for an electromagnetic wave shielding film that is a member of a plasma display.
The base film of the optical member is required to have excellent transparency and easy adhesion to functional layers such as a prism lens layer, a hard coat layer, an adhesive layer, an antireflection layer, and a sputter layer.

Generally, a hard coat layer is provided on a base film of an optical member. In order to obtain adhesion between the base film and the hard coat layer, an easy adhesion layer is provided on the base film. When a resin with a low glass transition temperature is used as the easy adhesion layer, sticking occurs when the film is wound or overlapped, the films do not slip, the handling property deteriorates, and it is difficult to slip There is a problem that the surface is easily scratched during film formation and processing. On the other hand, when a resin having a high glass transition temperature is used, adhesion when the films are overlapped is improved and handling properties are improved, but adhesion with the hard coat layer is poor, and transparency of the film is lowered. There's a problem.
Japanese Patent Laid-Open No. 10-110091

  It is an object of the present invention to provide an optically easily adhesive film having transparency and adhesiveness suitable as a base film of an optical member, and in which sticking between films is suppressed, i.e., having blocking resistance. .

  That is, the present invention comprises a polyester film and an easy-adhesion layer comprising a copolymer polyester provided on at least one surface thereof. It is an easily adhesive film for optics, characterized in that it is occupied by the dihydroxy compound represented, and 20 to 80 mol% is occupied by ethylene glycol.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the easily adhesive film for optics provided with transparency and adhesiveness suitable as a base film of an optical member, and the adhesion between films was suppressed, ie, provided with blocking resistance. .

Hereinafter, the present invention will be described in detail.
[Polyester film]
In the present invention, the polyester constituting the polyester film is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of such polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), and polyethylene-2,6-naphthalate. Polyethylene terephthalate or polyethylene-2,6-naphthalate is particularly preferred as the polyester because of good balance between mechanical properties and optical properties.

The polyester used for the polyester film may be a copolymer of the above polyester, or may be a blend of the polyester as a main component and other kinds of resins. When it is a copolymer, the proportion of the copolymer component is, for example, 20 mol% or less, and when it is a blend, the proportion of the other resin is, for example, 20 wt% or less.
In the present invention, the polyester film preferably contains no filler from the viewpoint of transparency.

In the present invention, the polyester film is transparent to other resins such as colorants, antistatic agents, ultraviolet absorbers, antioxidants, lubricants, catalysts, polyethylene, polypropylene, ethylene-propylene-polymers, and olefinic ionomers. You may contain in the range which does not impair property.
The thickness of the polyester film is preferably 25 to 300 μm, particularly preferably 50 to 250 μm, in order to obtain the strength required as an optical member.

[Easily adhesive layer]
In this invention, the easily bonding layer which consists of copolyester is provided in the at least one surface of the said polyester film. You may provide an easily bonding layer on both surfaces of a polyester film. This easy-adhesion layer is provided on the polyester film as a coating layer by coating.
The thickness of the easy adhesion layer is preferably 10 to 200 nm. By setting the thickness within this range, it is possible to obtain an easily adhesive film for optics that has sufficient adhesive force but maintains transparency.

The easy-adhesion layer is made of a copolyester, but may contain a crosslinking agent and fine particles in addition to the copolyester.
Hereinafter, the composition of the easy adhesion layer will be described in detail.

[Copolyester]
In the copolyester of the easy-adhesion layer in the present invention, 20 to 80 mol% of the diol component is occupied by a dihydroxy compound represented by the following formula, and 20 to 80 mol% is occupied by ethylene glycol.

  Among the diol components of the copolyester, the dihydroxy compound represented by the above formula occupies 61 to 80 mol% of the diol component, and ethylene glycol preferably occupies 39 to 20 mol%. By copolymerizing the dihydroxy compound represented by the above formula within this range, water dispersibility can be improved and at the same time, sticking between films can be prevented. Among the dihydroxy compounds, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene (hereinafter sometimes referred to as “BCF”) is particularly preferable. When the proportion of the hydroxy compound in the diol component of the copolymerized polyester is less than 20 mol%, the film has insufficient scratch resistance, and when it exceeds 80 mol%, sufficient adhesion cannot be obtained. When the proportion of ethylene glycol in the diol component of the copolymerized polyester is less than 20 mol%, the adhesion to the hard coat layer is lowered, and when it exceeds 80 mol%, the anti-blocking performance is lowered.

  As the dicarboxylic acid component of the copolymer polyester, any of aromatic dicarboxylic acid, saturated aliphatic dicarboxylic acid, and alicyclic dicarboxylic acid can be used. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid. Of these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred.

  Examples of the saturated aliphatic dicarboxylic acid include succinic acid, adipic acid, sebacic acid, and decamethylene dicarboxylic acid. Examples of the alicyclic dicarboxylic acid include cyclohexane dicarboxylic acid, decalin dicarboxylic acid, norbornane dicarboxylic acid, adamantane dicarboxylic acid, and tricyclodecene dicarboxylic acid. Among aliphatic dicarboxylic acids and alicyclic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid is industrially readily available, and a highly transparent and easily adhesive film can be obtained, which is most preferable.

  When an easy adhesion layer is provided by applying a copolymerized polyester as an aqueous dispersion to a polyester film, an easy adhesion layer is obtained in order to obtain good water dispersion and good blocking resistance of the resulting easy adhesion film. It is preferable that 0.1-10 mol% of the dicarboxylic acid component is occupied by an aromatic dicarboxylic acid component having a sulfonate group.

  Examples of the aromatic dicarboxylic acid having a sulfonate group include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, and 5-phosphonium sulfoisophthalic acid. From the viewpoint of improving water dispersibility, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, and particularly preferably 5-sodium sulfoisophthalic acid are preferred.

  The intrinsic viscosity of the copolyester is preferably 0.3 to 0.7, more preferably 0.4 to 0.7. By setting the intrinsic viscosity within this range, the copolyester can be easily produced, but the cohesive strength of the coating layer can be maintained, and good adhesiveness can be obtained.

[Crosslinking agent]
It is preferable to mix a cross-linking agent in the easy adhesion layer for the purpose of improving the solvent resistance during processing. As the crosslinking agent, epoxy, oxazoline, melamine and isocyanate are preferable. One of these may be used, or two or more may be used.

  Examples of the epoxy crosslinking agent include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, etc. Examples of the polyepoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diester. Glycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanurate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diepoxy compound, for example, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl Ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol Examples of glycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, and monoepoxy compound include, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compound. Examples thereof include N, N, N ′, N ′,-tetraglycidyl-m-xylylenediamine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

  The oxazoline crosslinking agent is preferably a polymer containing an oxazoline group. It can be prepared by polymerization with addition polymerizable oxazoline group-containing monomers alone or with other monomers. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 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-ethyl-2-oxazoline, and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer may be any monomer that can be copolymerized with an addition-polymerizable oxazoline group-containing monomer. For example, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n -(Meth) acrylic acid esters such as butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide N-alkyl methacrylamide N, N-dialkylacrylamide, N, N-dialkyl methacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl groups Unsaturated amides such as cyclohexyl groups, etc .; vinyl esters such as vinyl acetate, vinyl propionate, acrylic acid, methacrylic acid added with polyalkylene oxide; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether Α-olefins such as ethylene and propylene; halogen-containing α and β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; α and β-unsaturated aromatics such as styrene and α-methylstyrene Group monomers and the like, one or more of these It may be used monomers.

  The melamine crosslinking agent is preferably a compound obtained by reacting methylol melamine derivative obtained by condensing melamine and formaldehyde with ether such as methyl alcohol, ethyl alcohol, isopropyl alcohol as a lower alcohol, and a mixture thereof. Examples of the methylol melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine and the like.

  Isocyanate crosslinking agents include, for example, tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, adducts of tolylene diisocyanate and hexanetriol, tolylene diisocyanate and trimethylol Adduct of propane, polyol-modified diphenylmethane-4, 4′-diisocyanate, carbodiimide-modified diphenylmethane-4,4′-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3′-bitrylene-4,4 ′ diisocyanate, 3,3′dimethyldiphenylmethane-4,4′-diisocyanate, metaphenylene diisocyanate and the like.

  When the crosslinking agent is contained in the easy-adhesion layer, the content ratio of the copolymer polyester in the easy-adhesion layer is preferably 60 to 95% by weight, more preferably 70%, per 100% by weight of the total weight of the copolymer polyester and the crosslinking agent. The content of the crosslinking agent in the easy-adhesion layer is preferably 40 to 5% by weight, more preferably 10 to 30% by weight per 100% by weight of the total weight of the copolyester and the crosslinking agent. By setting the cross-linking agent in this range, good adhesion between the film and the hard coat layer can be obtained, and good solvent resistance can be obtained during processing of the hard coat layer.

[Fine particles]
The easy adhesion layer preferably contains fine particles. The fine particles contained in the easy adhesion layer preferably have an average particle diameter of 20 to 350 nm, more preferably 40 to 300 nm. If it exceeds 350 nm, the falling of the fine particles tends to occur, which is not preferable, and if it is less than 20 nm, sufficient lubricity and scratch resistance may not be obtained.

  Examples of the fine particles 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, antimony trioxide, Inorganic fine particles such as carbon black and molybdenum disulfide; organic fine particles such as acrylic cross-linked polymers, styrene cross-linked polymers, silicone resins, fluororesins, benzoguanamine resins, phenol resins, and nylon resins can be used. One of these may be used, or two or more may be used.

  When the easy-adhesion layer contains fine particles, the content ratio of the fine particles is preferably 0.1 to 10% by weight per 100% by weight of the composition of the easy-adhesion layer. If it is less than 0.1% by weight, sufficient lubricity and scratch resistance cannot be obtained, and it is not preferable. .

  The easily adhesive film of the present invention preferably has a surface haze value of 3% or less, and preferably has a static friction coefficient (μs) on the surface of the easily adhesive layer of 0.8 or less. When the surface haze value is within this range, transparency suitable as an optical member can be obtained, and when the coefficient of static friction is within this range, a film with good handling properties can be obtained.

[Production method]
The copolyester in the present invention can be produced by conventional polyester production techniques. Alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid or ester-forming derivatives thereof, and if necessary aromatic dicarboxylic acids having a sulfonate group, such as 5-sodium sulfoisophthalic acid or ester-forming derivatives thereof Can be produced by reacting ethylene glycol and a dihydroxy compound to form a monomer or oligomer, followed by polycondensation under vacuum to obtain a copolyester having a predetermined intrinsic viscosity. At this time, a catalyst for promoting the reaction, such as an esterification or transesterification catalyst or a polycondensation catalyst, can be used, and various additives such as a stabilizer can also be added.

  The copolymerized polyester is preferably in the form of an aqueous coating solution such as an aqueous solution, an aqueous dispersion or an emulsion to form a coating layer (hereinafter sometimes referred to as “coating film”), particularly preferably an aqueous dispersion. It is applied to a polyester film in the form of

  In order to form a coating film, in addition to the above components, other resins such as other polymer resins, other crosslinking agents, antistatic agents, colorants, surfactants, ultraviolet absorbers, waxes are formed as necessary. Etc. may be added. When adding a wax, it is 0.1-5 weight% per 100 weight% of coating layer total weight, Preferably it is 1-3 weight%.

  The solid content concentration of the aqueous coating liquid is usually 20% by weight or less, preferably 1 to 20% by weight, and more preferably 1 to 10% by weight. If it is less than 1% by weight, the wettability to the polyester film may be insufficient, and if it exceeds 20% by weight, the stability of the coating liquid and the appearance of the coating layer may be deteriorated.

  Among aqueous coating liquids, a preferable aqueous dispersion can be produced by the following method. First, the copolyester is dissolved in a hydrophilic organic solvent having a solubility in water of 1 liter at 20 ° C. or more and a boiling point of 100 ° C. or less, or azeotropic with water at 100 ° C. or less. Examples of the organic solvent include dioxane, acetone, tetrahydrofuran, and methyl ethyl ketone. A smaller amount of a surfactant may be added to such a solution.

  Next, water is added to the organic solvent in which the copolyester has been dissolved, preferably under heating and high-speed stirring, to obtain a blue-white to milky-white dispersion. A blue-white to milky white dispersion can also be obtained by a method of adding the organic solution to water under stirring.

When the organic solvent is separated and removed from the obtained dispersion, for example, the hydrophilic organic solvent is distilled off under normal pressure or reduced pressure, the desired aqueous polyester dispersion is obtained. If the copolyester is dissolved in a hydrophilic organic solvent azeotroped with water, the water will azeotropically evaporate when the organic solvent is distilled off. It is desirable to keep it.
The aqueous coating liquid may contain a crosslinking agent and fine particles, if necessary, in addition to the above-described copolymer polyester.

  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 moreover, it is applied to the polyester film before orientation crystallization is completed. Is preferred.

  Here, the polyester film before the crystal orientation is completed is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in two directions, the longitudinal direction and the transverse direction. And a film that has been stretched and oriented at a low magnification (a biaxially stretched film before being finally re-stretched in the machine direction or the transverse direction to complete oriented crystallization). The most preferable mode of application is to apply the aqueous coating solution to an unstretched film or a uniaxially stretched film oriented in one direction, and directly perform longitudinal stretching and / or lateral stretching and heat setting.

  When applying an aqueous coating solution to a polyester film, the film surface may be subjected to physical treatment such as corona surface treatment, flame treatment, plasma treatment, etc. as a pretreatment for improving coatability, or it may be chemically treated together with the composition. It is preferable to use an inert surfactant together. Such a surfactant improves the function of promoting the wetting of the aqueous coating liquid onto the polyester film and the stability of the coating liquid. For example, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid Anionic and nonionic surfactants such as metal soaps, alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates can be mentioned. It is preferable that the surfactant is contained in the coating liquid for forming the coating film so as to be 0.5 to 30% by weight per 100% by weight of the total weight of the coating layer.

  As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, and a curtain coating method can be used. These may be used alone or in combination.

Hereinafter, the present invention will be described in more detail with reference to examples.
Each characteristic value was measured by the following method.

(1) Thickness of the easy-adhesion layer The film is cut into small pieces, embedded with an epoxy resin, sliced into a 50 nm thickness with a microtome, dyed with 2% osmic acid at 60 ° C. for 2 hours, and dyed film Was observed with a transmission electron microscope (TECNAI G2LEM-2000), and the thickness of the easy-adhesion layer was measured.

(2) Scratch resistance A pin with a hard chrome plating having a diameter of 6 mm is fixed, and a film cut to a size of 20 cm in the longitudinal direction and 15 mm in the width direction is brought into contact with the pin at 90 °, and a constant speed (20 mm / s ), The degree of scratches entering the surface by sliding the surface of the easy adhesion layer of the film on the pin was evaluated.
A: Scratch area with respect to entire area ≦ 10% (very good)
○: 10% <Scratch area with respect to entire area ≦ 50% (good)
×: 50% <Scratch area relative to the total area (defect)

(3) Haze value According to JIS K7136, the haze of the film was measured using a haze measuring device (NDH-2000) manufactured by Nippon Denshoku Industries Co., Ltd., and the haze of the film was evaluated according to the following criteria.
A: Haze value ≦ 1.5% (very good)
○: 1.5% <haze value ≦ 3.0% (good)
×: 3.0% <haze value (defect)

(4) Friction coefficient (μs)
In accordance with ASTM D1894-63, a slippery measuring device manufactured by Toyo Tester was used to measure the static friction coefficient (μs) between the coating film forming surface and the polyethylene terephthalate film (coating film non-forming surface). However, the thread plate was a glass plate and the load was 1 kg. The slipperiness of the film was evaluated according to the following criteria.
A: Static friction coefficient (μs) ≦ 0.5 (very good)
○: 0.5 <Coefficient of static friction (μs) ≦ 0.8 (good)
×: 0.8 <Coefficient of static friction (μs) (Poor)

(5) Adhesiveness 2 g of UV curable resin (trade name: Desolite) manufactured by JSR Co., Ltd. was applied onto the coating surface of the film sample using a Myer bar. The film immediately after coating was dried at 80 ° C. for 2 minutes, and the sample was further irradiated with ultraviolet rays at 20 mW / cm ² for 5 minutes to form a 5 μm thick hard coat layer. After a hard coat layer is formed on the coating surface of the film sample, a cross cut (100 squares of 1 mm ² ) is applied on the surface, and a handy metal roll is used on the cross cut to obtain a width of 24 mm. The cellophane tape (CT405AP manufactured by Nichiban Co., Ltd.) was completely applied and peeled off rapidly at a peeling angle of 180 °, and then the peeled surface was observed and evaluated according to the following criteria.
A: Peeling area <10% (very good)
○: 10% ≦ peeling area <30% (good)
×: 30% ≦ peeling area (defect)

(6) Coating property The coating layer was observed with a halogen lamp for the full width and length of 3 m of the film, and the presence and degree of coating spots were evaluated. The application spots are machine direction streaks, machine direction vertical streaks, repellency, roll stain transfer marks, and the like.
A: Coating spots are less than 5% of the film observation area (very good)
○: Coating spots are 5% or more and less than 10% of film observation area (good)
X: Application spot is 10% or more of film observation area (defect)

(7) Blocking resistance Two films were overlapped so that the coated surfaces were in contact with each other, and a pressure of 0.6 kg / cm ² was applied to this under an atmosphere of 60 ° C. and 80% RH for 17 hours. Then, it peeled and the blocking resistance was evaluated according to the following criteria by its peeling force.
A: Peeling force <98 mN / 5 cm (very good)
○: 98 mN / 5 cm ≦ peeling force <196 mN / 5 cm (good)
×: 196 mN / 5 cm ≦ peeling force (defect)

(8) Glass transition temperature Approximately 10 mg of a sample is sealed in an aluminum pan for measurement and attached to a differential calorimeter (DuPont V4.OB2000 DSC), and the temperature is 25 ° C. to 300 ° C. at a rate of 20 ° C./min. The mixture was heated up to 300 ° C. for 5 minutes, then taken out, immediately transferred onto ice and rapidly cooled. The pan was again mounted on the differential calorimeter, and the glass transition temperature (Tg: ° C.) was measured by increasing the temperature from 25 ° C. to 20 ° C./min.

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

[Examples 1-6 and Comparative Examples 1-3]
Molten polyethylene terephthalate ([η] = 0.63 dl / g, Tg = 78 ° C.) is extruded from a die, cooled with a cooling drum by a conventional method to form an unstretched film, and then stretched 3.4 times in the machine direction. Then, an aqueous coating solution having a concentration of 5% shown in Table 2 was uniformly applied on one side with a roll coater. The composition of the copolyester in Table 2 is as shown in Table 1.

  Subsequently, this coated film was subsequently dried at 95 ° C., stretched 3.5 times at 120 ° C. in the transverse direction, shrunk 3% in the width direction at 220 ° C., and heat-fixed, and an adhesive film having a thickness of 125 μm. Got. The thickness of the coating layer was 0.08 μm. The evaluation results are shown in Table 3. In Comparative Example 1, no coating film was applied.

  In the table, CHD is 1,4-cyclohexanedicarboxylic acid, TA is terephthalic acid, NDC is 2,6-naphthalenedicarboxylic, NSIA is 3,5-sodium sulfoisophthalic acid, and EG is ethylene glycol. , BCF is 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene.

Polyester A:
The dicarboxylic acid component is composed of 99.9 mol% of 1,4-cyclohexanedicarboxylic acid / 5 mol of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 80 mol% of ethylene glycol / 20 mol% of BCF. Polyester A was produced as follows. That is, 100 parts by weight of dimethyl 1,4-cyclohexanedicarboxylate, 0.1 part by weight of dimethyl 5-sodium sulfoisophthalate, 24.8 parts by weight of ethylene glycol, and 37.8 parts by weight of BCF were charged into the reactor. 0.05 part of titanium was added and heated under a nitrogen atmosphere while controlling the temperature at 230 ° C., and the produced methanol was distilled off to conduct a transesterification reaction.

  Subsequently, the temperature of the reaction system was gradually raised to 255 ° C. in a polymerization kettle with high motor torque of a stirrer, and the inside of the system was reduced in pressure by 1 mmHg to carry out a polycondensation reaction. 25 parts of this polyester was dissolved in 75 parts of tetrahydrofuran, and 75 parts of water was dropped into the resulting solution under high-speed stirring at 10,000 rpm to obtain a milky white dispersion. Then, this dispersion was subjected to a reduced pressure of 20 mmHg. Distilled and the tetrahydrofuran was distilled off. An aqueous dispersion of polyester A was obtained.

Polyester B:
The dicarboxylic acid component is composed of 70 mol% of 1,4-cyclohexanedicarboxylic acid / 20 mol% of terephthalic acid / 5 mol of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 20 mol% of ethylene glycol / 80 mol% of BCF. Viscosity 0.51). The production method was the same as that for polyester A.

Polyester C:
The dicarboxylic acid component is composed of 99.9 mol% of 1,4-cyclohexanedicarboxylic acid / 5 mol of 0.1-sodium sulfoisophthalic acid, and the glycol component is composed of 39 mol% of ethylene glycol / 61 mol% of BCF (inherent viscosity of 0 49). The production method was the same as that for polyester A.

Polyester D:
The dicarboxylic acid component is 1,4-cyclohexanedicarboxylic acid 70 mol% / 2,6-naphthalenedicarboxylic acid 20 mol% / 5-sodium sulfoisophthalic acid 10 mol%, and the glycol component is composed of ethylene glycol 39 mol% / BCF 61 mol%. (Intrinsic viscosity 0.49). The production method was the same as that for polyester A.

Polyester E:
The dicarboxylic acid component is composed of 90 mol% of 1,4-cyclohexanedicarboxylic acid / 5 mol of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 80 mol% of ethylene glycol / 20 mol% of BCF (intrinsic viscosity 0.46). The production method was the same as that for polyester A.

Polyester F:
The dicarboxylic acid component is composed of 90 mol% of 1,4-cyclohexanedicarboxylic acid / 5 mol of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 39 mol% of ethylene glycol / 61 mol% of BCF (intrinsic viscosity 0.47). The production method was the same as that for polyester A.

Polyester G:
The dicarboxylic acid component is composed of 99.9 mol% of 1,4-cyclohexanedicarboxylic acid / 5 mol of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% of ethylene glycol / 10 mol% of BCF (inherent viscosity of 0 .45). The production method was the same as that for polyester A.

Polyester H:
The dicarboxylic acid component is composed of 99.9 mol% of 1,4-cyclohexanedicarboxylic acid / 5 mol of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 5 mol% of ethylene glycol / 95 mol% of BCF (inherent viscosity of 0 .50). The production method was the same as that for polyester A.

Cross-linking agent:
It is composed of 30% by mole of methyl methacrylate / 2% by mole of 2-isopropenyl-2-oxazoline / 10% by mole of polyethylene oxide (n = 10) methacrylate / 30% by mole of acrylamide (Tg = 50 ° C.). In addition, it manufactured as follows according to the method of the manufacture examples 1-3 of Unexamined-Japanese-Patent No. 63-37167. That is, 302 parts of ion-exchanged water was charged into a four-necked flask and heated to 60 ° C. in a nitrogen stream, and then 0.5 parts of ammonium persulfate and 0.2 part of sodium hydrogen nitrite were added as a polymerization initiator. Further, a mixture of monomers, 23.3 parts of methyl methacrylate, 22.6 parts of 2-isopropenyl-2-oxazoline, 40.7 parts of polyethylene oxide (n = 10) methacrylic acid, and 13.3 parts of acrylamide. The solution was added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. The reaction was continued with stirring while maintaining the same temperature range for 2 hours after the completion of the dropping, and then cooled to obtain an aqueous dispersion having a solid content of 25%.

Fine particles:
Polymethyl methacrylate cross-linked particles (average particle size: 150 nm) (trade name Epostor MX100W manufactured by Nippon Shokubai Co., Ltd.)
wax:
Carnauba wax (trade name Cerozol 524, manufactured by Chukyo Yushi Co., Ltd.)
Surfactant:
Polyoxyethylene (n = 7) lauryl ether

[Example 7]
Molten polyethylene terephthalate ([η] = 0.63 dl / g, Tg = 78 ° C.) was extruded from a die and cooled with a cooling drum by a conventional method to obtain an unstretched film. Next, an aqueous coating solution having a concentration of 5% shown in Table 2 was uniformly applied on one side with a roll coater. Next, this coated film was dried at 95 ° C., and subsequently stretched at 120 ° C. in the longitudinal direction by 3.4 times and in the transverse direction by 3.5 times. Subsequently, the film was shrunk 3% in the width direction at 220 ° C. and heat-fixed to obtain an easy-adhesive film having a thickness of 125 μm. In addition, the thickness of the easily bonding layer was 0.08 μm. The evaluation results are shown in Table 3.

  From the results shown in Table 3, the optical easy-adhesive film of the present invention has transparency, handling properties and adhesiveness suitable as an optical film, and the optical easy-adhesive property in which sticking between films is suppressed. Useful as a film.

  The easily adhesive film for optics of the present invention can be suitably used as a base film for optical members, particularly as a base film for optical members of plasma displays or liquid crystal displays.

Claims (2)

It consists of a polyester film and an easy-adhesion layer comprising a copolyester provided on at least one surface thereof, and the copolyester of the easy-adhesion layer is a dihydroxy compound in which 20 to 80 mol% of the diol component is represented by the following formula An easily adhesive optical film, characterized in that 20 to 80 mol% is occupied by ethylene glycol.

  The easily adhesive film for optics of Claim 1 used as a member of a plasma display or a liquid crystal display.