JP2003049011A - Readily adhering polyester film for optical use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a readily adhering polyester film for an optical use having excellent adhesion, transparency and easy slipperiness. SOLUTION: This readily adhering polyester film is characterized as follows. At least one surface of a polyester film has a coating layer comprising a polyester resin having the glass transition point within the range of 40-100 deg.C and a cross linking agent, and a scratch flow having >=1 mm length, >=0.5 mm width and >=0.5 μm depth is absent based on 4 m<2> area of the coating layer surface.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an easy-adhesive film, and more specifically, an easy-adhesive coating film made of a specific composition is formed on at least one side of a polyester film for excellent adhesion, transparency, and The present invention relates to an optical easy-adhesive polyester film having slipperiness.

[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 for various optical films such as members of liquid crystal display devices. In particular, demand for display films such as CRTs, LCDs, organic ELs and PDPs is growing. Since the display is required to have sharpness and visibility of images, the base film is required to have excellent transparency. In addition, excellent easy adhesion to hard coats, pressure sensitive adhesives, antireflection treatments, etc. is required.

For example, since an antireflection film used for display applications and a base film used for touch panel applications are required to have transparency, the amount of the internal filler is minimized or the internal filler is not added. Since it is necessary and has a very flat surface, scratches may occur during the film forming process, hard coat or adhesive processing process, etc.
It becomes an optical defect. Further, a hard coat or an easy-adhesion layer for the pressure-sensitive adhesive layer is applied to the base film. Polyester resin, acrylic resin, urethane resin and the like are generally used for this coating layer, but since these coating layers have poor scratch resistance, there is a problem that scratches may occur which may be an optical defect.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art, is excellent in scratch scratch resistance, transparency and slipperiness, and is excellent in adhesive strength with layers used in various optical applications. The present invention is intended to provide a polyester film.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have laminated a specific easily adhesive coating layer on the surface of a polyester film, and scratch scratches on the coating layer. It was found that the above problems can be solved by the absence of the above-mentioned problems, and the present invention has been completed.

That is, according to the present invention, (1) at least one surface of the polyester film has a glass transition point of 40 to 1
It has a coating layer containing a polyester resin in the range of 00 ° C. and a cross-linking agent, and a length of 1 m per 4 m ^{2 of the} surface of the coating layer.
An easily adhesive polyester film for optics, which is characterized by having no scratches of m or more, a width of 0.5 mm or more and a depth of 0.5 μm or more.

In a preferred embodiment of the present invention, (2) the crosslinking agent is at least one selected from the group consisting of epoxy compounds, oxazoline compounds, melamine compounds, isocyanate compounds and coupling agents. Optically easy-adhesive polyester film, (3) The polyester resin in the coating layer is 50 to 95% by weight, and the cross-linking agent is 1 to 40% by weight (1) or (2). -Resistant polyester film, and further, (4) the polyester constituting the polyester film is mainly composed of polyethylene terephthalate or polyethylene-2,6-naphthalate, and the optical easy-adhesiveness according to any one of (1) to (3). It is a polyester film.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION 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, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene-2,6-naphthalate, and the like. It may be a copolymer or a blend thereof with a small proportion of another resin. Of these polyesters,
Especially polyethylene terephthalate, polyethylene-2
6-naphthalate is preferable because it has a good balance of mechanical properties and optical properties.

These polyesters may contain a suitable filler, if necessary. As the filler, it is possible to use those conventionally known as a slipperiness-imparting agent for polyester films,
For example, calcium carbonate, calcium oxide, aluminum oxide, kaolin, silicon oxide, zinc oxide, carbon black, silicon carbide, tin oxide, crosslinked acrylic resin particles, crosslinked polystyrene resin particles, melamine resin particles, crosslinked silicone resin particles and the like. You can Further, a colorant, an antistatic agent, an antioxidant, an organic lubricant, a catalyst and the like can be appropriately added to the polyester.

The polyester film used in the present invention is
For example, the above polyester is melt extruded into a film,
An unstretched film is obtained by cooling and solidifying with a casting drum, and this unstretched film is stretched once or twice or more in the longitudinal direction at Tg to (Tg + 60) ° C. and the total magnification is 3 to 6 times.
Stretching to double, then stretching at Tg to (Tg + 60) ° C. in the width direction so as to have a magnification of 3 to 5 times, and further heat treatment at 180 to 230 ° C. for 1 to 60 seconds, and heat treatment. 0 in the width direction at a temperature 10 to 20 ° C lower than the temperature
It can be obtained by re-heat treatment while shrinking by -20%.

The thickness of the polyester film used in the present invention is preferably 25 to 300 μm, and particularly preferably 50 to 250 μm in order to obtain the strength required when used as a support for an optical film. .

The easily-adhesive coating layer in the present invention is free of scratches which can be an optical defect having a length of 1 mm or more, a width of 0.5 mm or more and a depth of 0.5 μm or more per surface area of 4 m ^2. is there. Area of coating layer surface 4m
Length 1mm or more per ^2, width 0.5mm or more, the depth 0.
If scratches of 5 μm or more are present, CRT, LC
Interference fringes and image omissions occur in images such as D and PDP, resulting in poor image clarity and visibility. On the surface of the coating layer, a length of 1 mm or more and a width of 0.5 mm or more per area of 4 m ² .
It is more preferable that there are no scratches with a depth of 0.2 μm or more.

In order to prevent such scratches, the components constituting the coating layer in the present invention have a glass transition point of 40 to 1
A polyester resin and a crosslinking agent in the range of 00 ° C are used.

In the present invention, the polyester resin used as a constituent component of the coating layer comprises a polybasic acid or its ester-forming derivative as shown below and a polyol or its ester-forming derivative, and has a glass transition point of 40 to 40.
It is in the range of 100 ° C. This glass transition point is 60
It is more preferably in the range of to 90 ° C. If the glass transition point of the polyester resin is less than 40 ° C, blocking between the films may occur, and if it exceeds 100 ° C, the coating layer becomes brittle and scratches are likely to occur.

Examples of the polybasic acid component of the polyester resin include 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, 5
-Sodium sulfoisophthalic acid and the like can be mentioned, but the invention is not limited thereto. The polyester resin is preferably a copolyester having two or more of these 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, if the amount is slight.

Examples of the polyol component of the polyester resin include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol,
1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, etc., poly (ethylene oxide) glycol, poly (tetramethylene oxide) glycol, etc., and these monomers can be mentioned, but they are not limited to these. It is not something that will be done.

The crosslinking agent used in the coating layer in the present invention is preferably at least one selected from the group consisting of epoxy compounds, oxazoline compounds, melamine compounds, isocyanate compounds and coupling agents. Epoxy compounds and oxazoline compounds are more preferable because they are easy to control the pot life of the coating liquid.

As the epoxy compound in the present invention,
Examples thereof include polyepoxy compounds, diepoxy compounds, monoepoxy compounds and glycidylamine compounds.

Examples of the polyepoxy compound include sorbitol, polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether. , Trimethylolpropane polyglycidyl ether and the like.

Examples of diepoxy compounds include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, Examples thereof include polypropylene glycol diglycidyl ether and polytetramethylene glycol diglycidyl ether.

Examples of the monoepoxy compound include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and examples of the glycidyl amine compound include N, N, N ', N',-tetraglycidyl-m-xylylenediamine, Examples thereof include 1,3-bis (N, N-diglycidylamino) cyclohexane.

The oxazoline compound used as the crosslinking agent in the present invention is preferably a polymer containing an oxazoline group. Such a polymer can be prepared by the addition-polymerizable oxazoline group-containing monomer alone or by polymerization with another monomer. The addition-polymerizable oxazoline group-containing monomer is 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 kind or a mixture of two or more kinds thereof can be used. Of these, 2-isopropenyl-2-oxazoline is industrially easily available and suitable. The other monomer is not limited as long as it is a monomer copolymerizable with the addition-polymerizable oxazoline group-containing monomer, and examples thereof include alkyl acrylate and alkyl methacrylate (wherein the alkyl group is a methyl group,
Ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group) and the like (meth) acrylic acid esters; acrylic acid, methacrylic acid, itacone Unsaturated carboxylic acids such as acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated acrylonitrile, methacrylonitrile, etc. Nitriles; acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, 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,
Unsaturated amides such as cyclohexyl group); vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene;
Examples thereof include halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene. It is possible to use one or more monomers.

As the melamine compound in the present invention,
A compound obtained by reacting a methylolmelamine derivative obtained by condensing melamine and formaldehyde with a lower alcohol such as methyl alcohol, ethyl alcohol or isopropyl alcohol and etherification, and a mixture thereof are preferable. As the methylolmelamine derivative, for example, monomethylolmelamine, dimethylolmelamine,
Trimethylol melamine, tetramethylol melamine,
Examples include pentamethylol melamine and hexamethylol melamine.

Examples of the isocyanate compound in the present invention include tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane and tolylene diisocyanate. And hexanetriol adduct, tolylene diisocyanate and trimethylolpropane adduct, polyol modified diphenylmethane-4,4'-diisocyanate, carbodiimide modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalenediisocyanate, 3,3
′ -Vitrylene-4,4 ′ diisocyanate, 3,3 ′
Examples thereof include dimethyldiphenylmethane-4,4'-diisocyanate and metaphenylene diisocyanate.

The coupling agent in the present invention is a compound represented by the general formula YRSiX ₃ , and examples thereof include a silane coupling agent. Here, Y is an organic functional group such as a vinyl group, an epoxy group, an amino group or a mercapto group, R is an alkylene group such as a methylene, ethylene or propylene group, X is a hydrolyzing group such as a methoxy group or an ethoxy group, and It is an alkyl group. It is particularly preferred that the Y moiety is an epoxy group. Specific preferred silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane and the like. In addition, organometallic compounds containing a metal such as zirconium, titanium and aluminum are preferably classified into alkoxides, chelates and acylates. Specific examples thereof include zirconium tetraacetylacetonate, zirconium acetate, titanium acetylacetonate, triethanolamine titanate, and titanium lactate, but are not limited thereto.

When a silane coupling agent is used as a cross-linking agent in the present invention, it is preferable to apply a coating liquid containing an organometallic compound containing a metal selected from zirconium, titanium and aluminum.

These cross-linking agents are preferably water-soluble or water-dispersible from the viewpoint of environmental pollution and explosion proof. Also,
From the viewpoint of rust prevention of manufacturing equipment and generation of toxic gas when products are incinerated and discarded, those containing no halogen element are preferable.

In the present invention, the proportion of the components constituting the coating layer is preferably 50 to 95% by weight of the polyester resin and 1 to 40% by weight of the crosslinking agent. The proportion of the polyester resin is more preferably 60 to 90% by weight, and the proportion of the crosslinking agent is more preferably 10 to 30% by weight. If the polyester resin content exceeds 95% by weight or the crosslinking agent content is less than 1% by weight, the cohesive force of the coating layer may decrease and scratch resistance may become insufficient. If the polyester resin in the coating layer is less than 50% by weight,
Alternatively, when the cross-linking agent exceeds 40% by weight, the coating layer becomes fragile and scratch resistance may be insufficient.

In the present invention, the coating layer formed on the surface of the polyester film preferably contains wax as a constituent component. By containing wax, more excellent slipperiness can be obtained. The slipperiness of the coating layer is preferably such that the friction coefficient (μs) is 0.8 or less.

Specific examples of this wax include plants such as carnauba wax, candelilla wax, rice wax, wax, jojoba oil, palm wax, rosin modified wax, auri curie wax, sugar cane wax, esparto wax and bark wax. Animal waxes such as beeswax, beeswax, lanolin, spermaceti, walnut wax, shellac wax, mineral waxes such as montan wax, ozokerite and ceresin wax, petroleum waxes such as paraffin wax, microcrystalline wax and petrolactam, Fischer trowel Synthetic hydrocarbon waxes such as push wax, polyethylene wax, oxidized polyethylene wax, polypropylene wax, and oxidized polypropylene wax.
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. Furthermore, an aqueous dispersion is more preferable because of environmental problems and easy handling.

The ratio of wax in the coating layer is 0.5 to 2
The range is preferably 0% by weight, and 1% by weight to 10%
More preferably, it is in the range of% by weight. If the proportion of wax is less than 0.5% by weight, slipperiness of the film surface may not be obtained. On the other hand, if it exceeds 20% by weight, the adhesion to a polyester substrate and the easy adhesion to a hard coat, a pressure-sensitive adhesive or the like may be insufficient.

In the present invention, the composition constituting the coating layer formed on the surface of the polyester film preferably further contains a filler. By containing the filler, more excellent slipperiness can be obtained.

Specific examples of the 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, and oxide. Inorganic fine particles such as tin, antimony trioxide, carbon black, molybdenum disulfide, acrylic cross-linked polymer, styrene cross-linked polymer, cross-linked silicone resin, fluororesin, benzoguanamine resin, phenol resin, nylon resin, etc. It can be illustrated. If these fillers are too large, they will fall out of the coating layer, so the average particle size is preferably 0.4 μm or less, and if they are too small, no slipperiness due to the filler will be expressed, and the range is 0.01 to 0.2 μm. Is preferred. Among these, it is preferable to select a filler having a specific gravity of not more than 3 for the water-insoluble solid substance in order to avoid sedimentation in the aqueous dispersion.

The filler may be contained in the composition forming the coating layer (hereinafter sometimes referred to as "coating film") in an amount of 5 to 30% by weight. In particular, from the range of 5 to 10% by weight when using a relatively large filler having an average particle size of 0.1 μm or more, and from the range of 8 to 30% by weight when using a filler having an average particle size of 0.01 to 0.1 μm. It is preferable to select it from the inside.

The above composition used in the present invention is preferably used in the form of an aqueous coating liquid such as an aqueous solution, an aqueous dispersion or an emulsion for forming a coating film. 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 liquid is usually 20% by weight.
It is below, and more preferably 1 to 10% by weight. If this proportion is less than 1% by weight, the wettability onto the polyester film may be insufficient, while if it exceeds 20% by weight, the stability of the coating composition and the coating appearance may deteriorate.

The application of the aqueous coating liquid 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).

Among them, 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 coatability, 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 polyester film with the aqueous coating liquid.
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.
Within this range, it can be reduced to 40 mN / m or less,
Repelling of the coating layer can be prevented.

The coating amount of the coating liquid is 0.02 to 0.02.
The amount is preferably 0.3 μm, preferably 0.04 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.

[0047]

EXAMPLES The present invention will be described in more detail with reference to examples. In Examples and Comparative Examples, the haze value, friction coefficient (μs), surface roughness (Ra), adhesiveness, and blocking resistance were evaluated by the following methods.

(1) Scratch scratch / size measurement area 4 m ² range (length 1.33 for film with width 3 m)
m film with a width of 2 m, a film sample with a length of 2 m) is used to visually observe the presence or absence of scratches on the coating layer using fluorescent light and reflected light of halogen light, and if there is, mark the location with a marker. The scratches are measured for length, width and depth with a laser optical microscope (VF-750) manufactured by Keyence Corporation. Length 1 mm or more, width 0.5
The number of scratches having a depth of 0.5 mm or more and a depth of 0.5 mm or more is determined. ⊚: Length 1 mm or more, width 0.5 mm or more, depth 0.2 μ
No scratches of m or more …… Very good ○: Length 1 mm or more, width 0.5 mm or more, depth 0.5 μ
No scratches of m or more ...... Good x: Length 1 mm or more, width 0.5 mm or more, depth 0.5 μ
One or more scratches of m or more present ... Bad

(2) Haze value The haze value of the film was measured using a haze meter (NDH-20) manufactured by Nippon Denshoku Industries Co., Ltd. The haze of the film was evaluated according to the following criteria. ⊚: Haze value ≦ 1.0% …… very good film haze ◯: 1.0% <haze value ≦ 1.5% …… good film haze ×: 1.5% <haze value …… film haze Bad

(3) Coefficient of friction (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

(4) 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 exceeds 40% ...... Adhesive strength is extremely poor

Adhesive (PSA) A thickness of 20 on the surface of the coating film 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. In addition, adhesive (PSA: Pressure-Sensitive-A
A urethane-containing acrylate copolymer (acrylic components were n-butyl acrylate (86 mol%) and methyl acrylate (14 mol%)) was used for dhesive). 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 strength 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

(5) Blocking resistance Two films were superposed so that the coating film-formed surface and the non-formed surface were in contact with each other, and 0.6 kg / kg of the film was applied in an atmosphere of 60 ° C. and 80% RH for 17 hours. Apply a pressure of cm ² ,
After that, peeling was performed, and the blocking resistance was evaluated according to the following criteria by the peeling force. A: Peeling force <98 mN / 5 cm ... Very good blocking resistance O: 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 x : 196 mN / 5 cm ≤ Peeling force ...... Poor blocking resistance

(6) 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 is raised to 00 ° C., and the temperature is kept at 300 ° C. for 5 minutes, then taken out, immediately transferred onto ice, and rapidly cooled. The pan is mounted on the differential calorimeter again, and the glass transition temperature (Tg: ° C) is measured by raising the temperature from 25 ° C at a rate of 20 ° C / min.

(7) Intrinsic viscosity The intrinsic viscosity ([η] dl / g) is measured with an o-chlorophenol solution at 25 ° C.

(8) Comprehensive Evaluation Evaluation was carried out according to the following criteria. ⊚: The adhesion to the hard coat and the adhesive is both 3 or more, and there is no Δ or × in the evaluation of scratches, haze, friction coefficient, and blocking resistance, and 3 or more items are ◎ (comprehensive evaluation Very good): Adhesiveness to the hard coat and the adhesive is both 3 or more, and there is no Δ or x in the evaluation of scratches, haze, friction coefficient, and blocking resistance, and 3 or more are ○ ( (Comprehensive evaluation: good) Δ: Adhesiveness to hard coat and adhesive is both 3 or more, and scratches, haze, friction coefficient, and blocking resistance are not evaluated as ×, and Δ is 1 or more ( (Comprehensive evaluation: Slightly good) ×: Adhesion to the hard coat and adhesive has a value of 2 or less, or scratches, haze, friction coefficient, and blocking resistance are evaluated. There exists more than one item (comprehensive evaluation and bad)

[Examples 1 to 5 and Comparative Examples 1 and 2] Molten polyethylene terephthalate ([η] = 0.65dl /
(g, Tg = 79 ° C.) is extruded from a die and cooled by a cooling drum by a conventional method to obtain an unstretched film, which is then stretched 3.4 times in the machine direction. The composition of each of the liquids 1 to 5 is the composition for coating film shown in Table 1 below.) Was uniformly applied with an aqueous coating liquid roll coater having a concentration of 8%.

[0058]

[Table 1]

Polyester 1: 2,6-naphthalenedicarboxylic acid as acid component 70 mol% / isophthalic acid 24 mol%
/ 5-sodium sulfoisophthalic acid 6 mol%, glycol component is composed of ethylene glycol 90 mol% / diethylene glycol 10 mol% (Tg = 85
C).

Polyester 1 is described in JP-A 06-11
It was manufactured as follows according to the method described in Example 1 of Japanese Patent No. 6487). That is, 70 parts of dimethyl 2,6-naphthalenedicarboxylate, 24 parts of dimethyl isophthalate, 5-
6 parts of sodium dimethyl sulfoisophthalate, 90 parts of ethylene glycol, and 10 parts of diethylene glycol were charged into a reactor, 0.05 parts of tetrabutoxytitanium was added to the reactor, and the temperature was controlled to 230 ° C. under a nitrogen atmosphere, followed by heating. The produced methanol was distilled off to carry out a transesterification reaction. Then gradually increase the temperature of the reaction system to 255
Polyester 1 was obtained by raising the temperature to 0 ° C. and reducing the pressure in the system to 1 mmHg to carry out polycondensation reaction.

Polyester 2: 66 mole% terephthalic acid
/ Isophthalic acid 22 mol% / trimellitic acid 4 mol% /
5-sodium sulfoisophthalic acid 8 mol% / ethylene glycol 90 mol% / diethylene glycol 10 mol% (Tg = 60 ° C.).

Polyester 2 is disclosed in JP-A-06-11.
It was manufactured as follows according to the method described in Example 1 of Japanese Patent No. 6487). That is, 66 parts of dimethyl terephthalate,
22 parts of dimethyl isophthalate, 4 parts of diethyl trimellitic anhydride, 8 parts of dimethyl 5-sodium sulfoisophthalate, 90 parts of ethylene glycol, 10 parts of diethylene glycol were charged to a reactor, and 0.05 part of tetrabutoxytitanium was added thereto. Temperature in a nitrogen atmosphere at 230 ° C
Then, 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 2.

Polyester 3: The acid component is terephthalic acid 3
It is composed of 0 mol% / isophthalic acid 64 mol% / 5-sodium sulfoisophthalic acid 6 mol% and the glycol component is 80% ethylene glycol / 20 mol% diethylene glycol (Tg = 20 ° C.).

Polyester 3 is described in JP-A-06-11.
It was manufactured as follows according to the method described in Example 1 of Japanese Patent No. 6487). That is, 30 parts of dimethyl terephthalate,
64 parts dimethyl isophthalate, 6 parts dimethyl 5-sodium sulfoisophthalate, 80 parts ethylene glycol,
20 parts of diethylene glycol was charged into a reactor, 0.05 part of tetrabutoxytitanium was added thereto, and the temperature was controlled at 230 ° C. in a nitrogen atmosphere to heat the resulting methanol to distill off the produced ester exchange reaction. It was
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 3.

Crosslinking agent 1: 25 mol% of methyl methacrylate / 2 mol% of 2-isopropenyl-2-oxazoline
/ Polyethylene oxide (n = 10) methacrylate 1
It is composed of 0 mol% / acrylamide 35 mol%.

The crosslinking agent 1 is disclosed in JP-A-63-37167.
It was manufactured as follows according to the method described in Production Examples 1 to 3 of the publication. 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 25 parts of methyl methacrylate, 30 parts of 2-isopropenyl-2-oxazoline, 10 parts of polyethylene oxide (n = 10) methacrylic acid, acrylamide 35 parts of mixture over 3 hours, the liquid temperature is 60 ~ 70 ° C.
Was added while adjusting so that 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 a crosslinking agent 1 having a solid content of 35%.

Cross-linking agent 2: 1,3-bis (N, N-diglycidylamino) cyclohexane (trade name Tetrad C manufactured by Mitsubishi Gas Chemical Co., Inc.) Cross-linking agent 3: methylol melamine (trade name manufactured by Sanwa Chemical Co., Ltd.) MX-035) Additive 1: Silica filler (100 nm) (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 (trade name Naloacty N-7 manufactured by Sanyo Kasei Co., Ltd.)
0)

The coated film is then continued for 9
Dry at 5 ° C and stretch laterally at 120 ° C 3.7 times,
Shrink 3% in the width direction at 220 ° C and heat set to a thickness of 188
An easily adhesive film having a thickness of μm was obtained. The thickness of the coating film is 0.
It was 15 μm.

[Example 6] Molten polyethylene-2,6-
Naphthalate ([η] = 0.63 dl / g, Tg = 12
(1 ° C.) was extruded from a die, cooled by a cooling drum by a conventional method to give an unstretched film, and then stretched 3.5 times in the machine direction, and then the coating composition (Coating liquid 1 in Table 1) was formed on both surfaces of the unstretched film. 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 in the transverse direction at 140 ° C. 3.7 times, 230
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 0.15μ
It was m.

[0070]

[Table 2]

[0071]

According to the easily adhesive polyester film for optics of the present invention, a film having excellent adhesiveness, transparency and slipperiness can be obtained by using a specific easily adhesive layer. Further, the film of the present invention is particularly useful for various optical applications, particularly 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.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C08L 67:00 C08L 67:00 (72) Inventor Koji Kubo 3-37-19 Oyama, Sagamihara City, Kanagawa Prefecture No. Teijin DuPont Films Co., Ltd. Sagamihara Research Center F-term (reference) 4F006 AA35 AB35 AB64 AB65 AB67 BA01 BA02 BA09 CA05 CA08 4F100 AH02B AH02C AH03B AH03C AH07B AH07C AK41A AK41B AK41C BA02 BA03 BA06 CA41 BA02 BA10 BA02 BA10 BA02 BA10 BA02 BA10 BA02 BA10 BA02 BA10 BA02 JA05C JK12B JK12C JL00 JL11 JN01 YY00B YY00C 4J038 CK022 DA162 DB002 DD061 DD081 DG111 JA69 JC32 KA03 MA13 NA01 NA10 NA11 NA12 PB08 PC08 4J040 EC002 ED041 EF111 HC25 HC26 KA16 LA01 LA10 MA10 MB09 NA

Claims (4)

[Claims] 1. A coating layer containing a polyester resin having a glass transition point in the range of 40 to 100 ° C. and a cross-linking agent is provided on at least one surface of a polyester film, and a length of 1 mm per 4 m ² area of the surface of the coating layer. As described above, the easily adhesive polyester film for optics having no scratches having a width of 0.5 mm or more and a depth of 0.5 μm or more. 2. The easily adhesive polyester film for optics according to claim 1, wherein the crosslinking agent is at least one selected from the group consisting of an epoxy compound, an oxazoline compound, a melamine compound, an isocyanate compound and a coupling agent. 3. The polyester resin in the coating layer is 50 to 9
The easily adhesive polyester film for optics according to claim 1 or 2, which is 5% by weight and the crosslinking agent is 1 to 40% by weight. 4. The optical adhesive polyester film according to claim 1, wherein the polyester constituting the polyester film is mainly composed of polyethylene terephthalate or polyethylene-2,6-naphthalate.