JP2003119305A - Readily bondable polyester film for optical use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a readily bondable polyester film for optical use having excellent adhesiveness, transparency and slip properties. SOLUTION: This readily bondable polyester film for optical use is provided with a coating layer comprising a polyester resin and an acrylic resin containing an oxazoline group and a polyalkylene oxide chain on at least one side of the polyester film.

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 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 and excellent adhesion to a prism lens, a hard coat, an adhesive, an antireflection treatment and the like.

Biaxially oriented polyester films generally have poor adhesion to other materials, for example, prism lenses and a hard coat containing acrylic resin as a main component. It has been proposed to stack and use an easy-adhesion layer such as a urethane resin (for example, JP-A-10-119215).
JP-A-2000-246855, etc.). However, in the case where the easy-adhesion layer made of these resins is formed,
The adhesive strength may be insufficient. For example, a film for CRT has good adhesion to the hard coat layer but insufficient adhesion to the adhesive layer on the opposite side, and thus lacks versatility.

On the other hand, the optical base film is required to have transparency, and therefore it is usually necessary to minimize the amount of the internal 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, in the optical film, since the minimum amount of the internal filler is added, the film surface is flat, and when a resin having a low glass transition point is used for the easy-adhesion layer, the film is wound or laminated. At the same time, sticking occurs, the films do not slide and the handling property deteriorates, and there is a problem that the surface is easily scratched during film formation and processing because it is difficult to slip.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art, and is a polyester film having excellent adhesiveness to layers used for various optical applications, and having excellent transparency and slipperiness. It is intended to provide.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors of the present invention have found that the surface of a polyester film contains a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain. It has been found that the above problems can be solved by forming an adhesive coating film, and the present invention has been completed.

That is, according to the present invention, (1) a coating layer containing a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain is provided on at least one surface of the polyester film. An adhesive polyester film is provided.

In a preferred embodiment of the present invention, (2) the coating layer contains 5 to 90% by weight of a polyester resin and 5 to 90% by weight of an acrylic resin having an oxazoline group and a polyalkylene oxide chain (1). The optical easy-adhesive polyester film according to the item (3), further comprising (3) the coating layer containing 0.5 to 30% by weight of an aliphatic wax, the optical easy-adhesive polyester film according to the item (1) or (2), (4) Particle size in the coating layer is 0.005 to 0.5 μm
0.1 to 20% by weight of filler in the range of (1)
To (3), the haze value of the easily adhesive polyester film for optics according to any one of (3) and (5) the polyester film is 1.5% or less, and the center line average roughness (Ra) of the coating layer surface is The easily adhesive polyester film for optics according to any one of (1) to (4), wherein the friction coefficient (μs) of the coating layer surface is 0.8 or less in the range of 0.002 to 0.01 μm. (6) The polyester constituting the polyester film is the optical adhesive polyester film according to any one of (1) to (5), which is mainly composed of polyethylene terephthalate or polyethylene-2,6-naphthalate.

[0010]

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

The polyester constituting the polyester film in the present invention 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 25 in order to obtain the strength required when it is used as a support for hard coat, touch panel, antiglare treatment and the like.
To 300 μm is preferable, and especially 50 to 250
It is preferably μm.

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

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

Examples of the polybasic acid component of the polyester resin include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid and 1,4-
Cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, dimer acid, 5
-Sodium sulfoisophthalic acid and the like can be mentioned. It is preferable that these acid components are two or more kinds of copolyesters. 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 acrylic resin having an oxazoline group and a polyalkylene oxide chain used in the coating layer in the present invention is
Acrylics that are soluble or dispersible in water (which may contain some organic solvent) are preferred. Examples of the acrylic resin having an oxazoline group and a polyalkylene oxide chain include those containing the following monomers as components.

As the monomer having an oxazoline group, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-
Examples include oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and one or two of these. Mixtures of the above 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. Further, it is possible to impart abrasion resistance to a metal roll in the film forming step or the hard coat processing step.

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

Other copolymerizable components of the acrylic resin include, for example, the following monomers. That is, alkyl acrylate, alkyl methacrylate (as the alkyl group, a methyl group, an ethyl group, an n-propyl group,
(Isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.); 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, etc. A hydroxy-containing monomer; glycidyl acrylate,
Epoxy group-containing monomers such as glycidyl methacrylate and allyl glycidyl ether; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary) Monomers having a carboxy group such as amine salt) or a salt thereof; acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N, N-dialkylacrylamide, N, N-dialkylmethacrylate (as an 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, (the alkoxy group, methoxy group, an ethoxy group, a butoxy group, isobutoxy group, etc.) N- dialkoxy acrylamide, N, N-dialkoxy methacrylamide, acryloyl morpholine,
Monomers having amide groups such as N-methylolacrylamide, N-methylolmethacrylamide, N-phenylacrylamide, N-phenylmethacrylamide; acid anhydride monomers such as maleic anhydride and itaconic anhydride; vinyl isocyanate, allyl isocyanate, Styrene, -methylstyrene, vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, alkyl itaconic acid monoester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, Examples thereof include vinyl chloride, vinyl acetate, butadiene, etc., but are not limited to these monomers.

The content ratio of the polyester resin forming the coating layer in the coating layer is preferably 5 to 95% by weight, and particularly preferably 50 to 90% by weight. The content of the acrylic resin having an oxazoline group and a polyalkylene oxide chain forming the coating layer in the coating layer is 5 to
It is preferably 90% by weight, particularly preferably 10 to 50% by weight. When the polyester resin content exceeds 95% by weight or the acrylic resin having an oxazoline group and a polyalkylene oxide chain is less than 5% by weight, the cohesive force of the coating layer decreases, resulting in insufficient adhesion to the hard coat or pressure-sensitive adhesive. May be. 90 acrylic resin
When the content is more than 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.

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

Specific examples of the above aliphatic wax include carnauba wax, candelilla wax, rice wax,
Tree wax, jojoba oil, palm wax, rosin modified wax, auri curie wax, sugar cane wax, esparto wax, bark wax and other plant waxes, beeswax, lanolin, whale wax, ivota wax, shellac and other animal waxes, montan Mineral wax such as wax, ozokerite and ceresin wax, paraffin wax, microcrystalline wax, petroleum wax such as petrolactam, Fischer-Tropsch wax, polyethylene wax, oxidized polyethylene wax, polypropylene wax, synthetic hydrocarbon such as polypropylene oxide wax System 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. In particular, an aqueous dispersion is more preferable because of environmental problems and easy handling.

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

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, tin oxide. , Inorganic fine particles such as antimony trioxide, carbon black, molybdenum disulfide, acrylic cross-linked polymer, styrene cross-linked polymer, silicone resin, fluororesin, benzoguanamine resin, phenol resin, nylon resin, polyethylene wax, etc. Can be mentioned. Of these, water-insoluble solid substances, in order to avoid settling in the aqueous dispersion,
It is preferable to select ultrafine particles having a specific gravity not exceeding 3.

The optically easily 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. It is preferable that the friction coefficient (μs) is 0.8 or less. Such an optically easy-adhesive polyester film can be obtained by forming a coating layer made of the above composition.

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

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

The application of the aqueous coating 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 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 coating property, or it is applied together with the composition. And a chemically inactive surfactant are preferably used together.

Such a surfactant accelerates the wetting of the 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.

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 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.

[0039]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. In addition, the part in an Example represents a weight part. 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) 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

(2) 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.

[0042]

[Equation 1] (3) Friction coefficient (μs) According to ASTM D1894-63, using a slippery measuring device manufactured by Toyo Tester Co., Ltd., static friction coefficient (μs) between the coating film-formed surface and the polyethylene terephthalate film (non-coated surface). 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, cross-cut (100 squares of 1 mm ² ) is applied, and 2
A 4 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) was attached, and after rapidly peeling 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 film having a thickness of 20 on the surface on which the easily-adhesive polyester film is formed.
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-Sensitive)
-Adhesive) was a urethane-containing acrylate copolymer (acryl components were n-butyl acrylate (86 mol%) and methyl acrylate (14 mol%)). 5: Adhesive (PSA) residual area is less than 10% .... Adhesive strength is very good. 4: Adhesive (PSA) residual area is 10% or more and less than 20% ..... Adhesive strength is 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

(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 then 0.6 kg / kg for 17 hours in an atmosphere of 60 ° C. and 80% RH. 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. ⊚: 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 …… Blocking resistance Slightly good ×: 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 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 surface roughness (Ra) is in the range of 0.002 to 0.01 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) O: Surface roughness (Ra) is in the range of 0.002 to 0.01 μm, both adhesion to the hard coat and the adhesive is 3 or more, and haze and friction coefficient are In the evaluation of blocking resistance, ◯ is present, and Δ and x are not present (comprehensive evaluation / good) Δ: Surface roughness (Ra) is in the range of 0.002 to 0.01 μm, and hard coat and adhesion Adhesiveness to the agent is both 3 or more, and Δ is present in the evaluation of haze, coefficient of friction, and blocking resistance (x is not present) (Comprehensive evaluation: somewhat good) x: Surface roughness (Ra) is 0.002 ~ 0.01μ Out of range or is in, if there are two or less in adhesion to the hard coat and adhesive, or haze, frictional coefficient, × occurs more than one item in the evaluation of blocking resistance (Comprehensive evaluation and bad)

[Examples 1 to 4, Comparative Examples 1 and 2] Molten polyethylene terephthalate ([η] = 0.63 dl / g,
(Tg = 79 ° C.) is extruded from a die and cooled by a cooling drum by an ordinary method to obtain an unstretched film, and then 3. in the machine direction.
After being stretched 4 times, the coating material (Coating liquid 1
The compositions of Nos. 6 to 6 are coating compositions shown in Table 1 below), and an aqueous coating solution having a concentration of 8% was uniformly applied with a roll coater.

[0051]

[Table 1] Polyester 1: 2,6-naphthalenedicarboxylic acid 65 mol% as acid component / isophthalic acid 30 mol% / 5-sodium sulfoisophthalic acid as 5 mol%, glycol component as ethylene glycol 90 mol% / diethylene glycol 1
It is composed of 0 mol% (Tg = 80 ° C., average molecular weight 13000).

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, 44 parts of dimethyl 2,6-naphthalenedicarboxylate, 16 parts of dimethyl isophthalate, 5-
4 parts of sodium dimethyl sulfoisophthalate, 34 parts of ethylene glycol, and 2 parts of diethylene glycol were charged into a reactor, 0.05 parts of tetrabutoxytitanium was added thereto, and the temperature was controlled at 230 ° C. under a nitrogen atmosphere to heat. The produced methanol was distilled off to carry out a transesterification reaction. Then gradually raise the temperature of the reaction system to 255 ° C.
Up to 1 mmHg to reduce the pressure in the system to a polycondensation reaction to obtain polyester 1.

Polyester 2: Acid component is terephthalic acid 6
It is composed of 0 mol% / 35 mol% isophthalic acid / 5 mol% 5-sodium sulfoisophthalic acid, and the glycol component is 90 mol% ethylene glycol / 10 mol% diethylene glycol (Tg = 45 ° C., average molecular weight 140).
00) Polyester 2 was produced according to the method described in Example 1 of JP-A 06-116487) as follows. That is, 36 parts of dimethyl terephthalate, 21 parts of dimethyl isophthalate, 5 parts of dimethyl 5-sodium sulfoisophthalate, 36 parts of ethylene glycol, and 2 parts of diethylene glycol were charged into a reactor, and 0.05 part of tetrabutoxytitanium was added thereto. Temperature in a nitrogen atmosphere at 23
The temperature was controlled at 0 ° C. and heating was performed to distill off the produced methanol to carry out a transesterification reaction. Next, the temperature of the reaction system was gradually raised to 255 ° C. and the pressure inside the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain polyester 1.

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

Acrylic 1 is disclosed in JP-A-63-3716.
It manufactured as follows according to the method of manufacture example 1-3 of the gazette No. 7. That is, a four-necked flask was charged with 3 parts of sodium laurylsulfonate as a surfactant and 181 parts of ion-exchanged water and heated to 60 ° C. in a nitrogen stream, and then ammonium persulfate 0.5 part was added as a polymerization initiator.
Parts, 0.2 parts of sodium hydrogen nitrite 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 aqueous dispersion of acrylic 1 having a solid content of 35%.

Acrylic 2: Methyl methacrylate 30 mol% / 2-isopropenyl-2-oxazoline 40 mol% / acrylamide 30 mol% (Tg
= 80 ° C).

Acrylic 2 is disclosed in JP-A-63-3716.
It manufactured as follows according to the method of manufacture example 1-3 of the gazette No. 7. That is, a four-necked flask was charged with 3 parts of sodium laurylsulfonate as a surfactant and 181 parts of ion-exchanged water and heated to 60 ° C. in a nitrogen stream, and then ammonium persulfate 0.5 part was added as a polymerization initiator.
Part, and 0.2 part of sodium hydrogen nitrite are added, and a mixture of 34.9 parts of methyl methacrylate, 45.2 parts of 2-isopropenyl-2-oxazoline and 19.9 parts of acrylamide, which are monomers, is further added. Liquid temperature is 6 over time
The mixture was added dropwise while adjusting to 0 to 70 ° C. After the dropping was completed, the reaction was continued under stirring while maintaining the same temperature range for 2 hours and then cooled to obtain an aqueous dispersion of acrylic 2 having a solid content of 35%.

Acrylic 3: 45 mol% of methyl methacrylate / 45 mol% of butyl acrylate / 5 mol% of glycidyl methacrylate / 5 mol% of 2-hydroxyethyl methacrylate (Tg = 50 ° C.).

Acrylic 3 is disclosed in JP-A-63-3716.
It manufactured as follows according to the method of manufacture example 1-3 of the gazette No. 7. That is, a four-necked flask was charged with 3 parts of sodium laurylsulfonate as a surfactant and 181 parts of ion-exchanged water and heated to 60 ° C. in a nitrogen stream, and then ammonium persulfate 0.5 part was added as a polymerization initiator.
Parts, 0.2 parts of sodium hydrogen nitrite are added, and further monomers 38.7 parts of methyl methacrylate, 49.6 parts of butyl acrylate, 6.1 of glycidyl methacrylic acid are added.
And 5.6 parts of 2-hydroxyethylmethacrylic acid were added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. After the dropping was completed, the reaction was continued under stirring while maintaining the same temperature range for 2 hours, and then cooled to obtain an aqueous dispersion of acrylic 3 having a solid content of 35%.

Additive 1: Silica filler (average particle size: 1
00nm) (Nissan Chemical Co., Ltd. trade name Snowtex ZL) Additive 2: Carnauba wax (Chukyo Yushi Co., Ltd. trade name Cerosol 524) Wetting agent: polyoxyethylene (n = 7) lauryl ether (Sanyo Chemical Co., Ltd.) Product name Naloacty N-7
0) Then, the coated film was subsequently dried at 95 ° C., stretched in the transverse direction at a temperature of 120 ° C. by 3.7 times, contracted at 220 ° C. in the width direction by 3% and heat-set to easily adhere to a thickness of 188 μm. To obtain a film. The thickness of the coating film was 0.15 μm.

[Example 5] 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 0.15μ
It was m.

[0062]

[Table 2]

[0063]

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 useful for various optical applications, particularly for base films such as prism lens sheets, touch panels, and backlights, base films for antireflection films, and explosion-proof base films for displays.

Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) // C08L 67:00 G02B 1/10 Z (72) Inventor Koji Kubo 3-37-19 Koyama, Sagamihara City, Kanagawa People DuPont Films Co., Ltd. Sagamihara Research Center F-term (reference) 2K009 AA15 BB24 CC24 DD01 EE00 4F006 AA35 AB24 AB35 BA01 CA05 DA04 4J038 BA212 CB002 CC022 CD092 CG001 CG002 CG141 CG142 DA032 DA216 DD061 DD062 DH002 HA0326 HA02 GA03 HA026 HA02 KA08 KA20 NA12 NA17 PB08 PC08

Claims (6)

[Claims] 1. An easy-adhesive polyester film for optics, characterized in that a coating layer containing a polyester resin and an acrylic resin having an oxazoline group and a polyalkylene oxide chain is provided on at least one surface of the polyester film. 2. A polyester resin in the coating layer is 5 to 90.
The easily adhesive polyester film for optics according to claim 1, wherein the acrylic resin having an oxazoline group and a polyalkylene oxide chain is contained in an amount of 5 to 90% by weight. 3. Aliphatic wax is 0.5 to 3 in the coating layer.
The easily adhesive polyester film for optics according to claim 1, wherein the polyester film contains 0% by weight. 4. The coating layer has a particle size of 0.005 to 0.5.
The easily adhesive polyester film for optics according to any one of claims 1 to 3, which contains 0.1 to 20% by weight of the filler in the range of µm. 5. The haze value of the polyester film is 1.
5% or less, the center line average roughness (Ra) of the coating layer surface
Is in the range of 0.002 to 0.01 μm, and the friction coefficient (μs) on the surface of the coating layer is 0.8 or less. 5. The easily adhesive polyester film for optical use according to claim 1, wherein 6. The easily adhesive polyester film for optics according to claim 1, wherein the polyester constituting the polyester film is mainly composed of polyethylene terephthalate or polyethylene-2,6-naphthalate.