JP2008116710A - Easily adhering polyester film for optical use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily adhering polyester film for optical use which is excellent in adhesive strength with a functional layer used for the optical use such as a member of a plasma display panel and a member of a liquid crystal display, transparency and light resistance and further which has the small number of defects due to sticking of foreign substances onto a surface. <P>SOLUTION: The easily adhering polyester film for optical use comprises a polyester film containing an ultraviolet ray absorption agent and an easily adhering layer provided thereon and melting subpeak temperature (Tsm) of the film is ≥180°C and <220°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an easily adhesive polyester film for optics.

Polyester films used for optical applications, particularly plasma display panels (hereinafter sometimes referred to as PDP) and liquid crystal display (hereinafter sometimes referred to as LCD) members, are UV absorbers for light resistance. May be added. However, the ultraviolet absorber may bleed out in the heat setting step of the polyester film, and the recrystallized ultraviolet absorber may adhere to the film surface, resulting in surface defects.
JP 2004-250624 A

  The present invention eliminates the problems of the prior art, and is excellent in adhesion, transparency and light resistance with functional layers used for optical applications such as PDP and LCD members, and has the number of defects due to adhesion of foreign matter to the surface. An object of the present invention is to provide an optically easy-adhesive polyester film with a small amount.

  The present invention consists of a polyester film containing an ultraviolet absorber and an easy adhesion layer provided thereon, and has a melting subpeak temperature (Tsm) of 180 ° C. or higher and lower than 220 ° C. Is a conductive polyester film.

  According to the present invention, an easily adhesive polyester film for optical use having excellent adhesion, transparency and light resistance to functional layers used for optical applications such as PDP and LCD members, and having a small number of defects due to foreign matter adhesion to the surface. Can be provided.

Hereinafter, the present invention will be described in detail.
[Polyester film]
In the present invention, the polyester film used for the base film of the optically easy-adhesive polyester film comprises a polyester composition containing an ultraviolet absorber. Examples of the polyester constituting the polyester film include aromatic dicarboxylic acid components such as terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, and 4,4′-diphenyldicarboxylic acid, and ethylene glycol and 1,4-butane. Aromatic polyesters composed of glycol components such as diol, 1,4-cyclohexanedimethanol and 1,6-hexanediol are preferred, and polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate are particularly preferred. Further, it may be a copolyester such as the above components.

  Polyester has organic or inorganic fine particles as a lubricant as necessary to improve the film winding property during film formation and the film transportability when a hard coat layer or adhesive is applied. Can be contained. Examples of such fine particles include calcium carbonate, calcium oxide, aluminum oxide, kaolin, silicon oxide, zinc oxide, crosslinked acrylic resin particles, crosslinked polystyrene resin particles, urea resin particles, melamine resin particles, and crosslinked silicone resin particles. In addition to fine particles, other resins such as colorants, antistatic agents, antioxidants, lubricants, catalysts, polyethylene, polypropylene, ethylene-propylene-polymers, olefinic ionomers, etc. are within the range that does not impair the transparency. You may make it contain.

[Ultraviolet absorber]
In the present invention, the polyester film contains an ultraviolet absorber to obtain light resistance. As this ultraviolet absorber, at least one compound selected from the cyclic imino ester represented by the following formula (I) and the cyclic imino ester represented by the following formula (II) is preferably used in an unreacted form.

（式（Ｉ）で、Ｘ^１は、上記式に表わされたＸ^１からの２本の結合手が１位、２位の位置関係にある、２価の芳香族残基であり；ｎは１、２または３であり；Ｒ^１はｎ価の炭化水素残基で、これはさらにヘテロ原子を含有していてもよい、またはＲ^１はｎ＝２のとき直接結合であることができる。）

(In the formula (I), X ¹ is a divalent aromatic residue in which two bonds from X ¹ represented by the above formula are in a positional relationship of 1-position and 2-position; n Are 1, 2 or 3; R ¹ is an n-valent hydrocarbon residue, which may further contain heteroatoms, or R ¹ may be a direct bond when n = 2 .)

（式（ＩＩ）で、Ａは下記式（ＩＩ）−ａで表わされる基であるかまたは下記式（ＩＩ）−ｂで表わされる基であり；Ｒ^２およびＲ^３は同一もしくは異なり１価の炭化水素残基であり；Ｘ^２は４価の芳香族残基で、これはさらにヘテロ原子を含有していてもよい。）

(In the formula (II), A is a group represented by the following formula (II) -a or a group represented by the following formula (II) -b; R ² and R ³ are the same or different and are monovalent. A hydrocarbon residue; X ² is a tetravalent aromatic residue, which may further contain heteroatoms.)

  Such a cyclic imino ester is a compound known as an ultraviolet absorber and is described, for example, in JP-A-59-12952.

In the general formula (I), X ¹ is a divalent aromatic residue in which two bonds from X ¹ represented by the formula (I) are in the 1-position and 2-position positional relationship; n is 1, 2 or 3; R ¹ is an n-valent hydrocarbon residue, which may further contain a heteroatom, or R ¹ may be a direct bond when n = 2 it can.

X ¹ is preferably 1,2-phenylene, 1,2-naphthylene, 2,3-naphthylene, or a group represented by the following formula (a) or (b). Of these, 1,2-phenylene is particularly preferable.

（式（ａ）または（ｂ）中、Ｒは−Ｏ−、−ＣＯ−、−Ｓ−、−ＳＯ_２−、−ＣＨ_２−、−（ＣＨ_２）−または−Ｃ（ＣＨ_３）_２−である。）

(In the formula (a) or (b), R represents —O—, —CO—, —S—, —SO ₂ —, —CH ₂ —, — (CH ₂ ) — or —C (CH ₃ ) ₂ —. .)

The aromatic residue exemplified for X ¹ is, for example, alkyl having 1 to 10 carbon atoms such as methyl, ethyl, propyl, hexyl, decyl, etc .; aryl having 6 to 12 carbon atoms such as phenyl, naphthyl, etc .; Cycloalkyl such as cyclopentyl, cyclohexyl, etc .; C 8-20 aralkyl such as phenylethyl; C 1-10 alkoxy such as methoxy, ethoxy, decyloxy, etc .; nitro; halogen such as chlorine, bromine, etc .; C 2-10 And may be substituted with a substituent such as acetyl, proponyl, zenzoyl, decanoyl, etc.

R ¹ can be an n-valent hydrocarbon residue (where n is 1, 2 or 3) or can be a direct bond only when n is 2.
As the monovalent hydrocarbon residue (when n = 1), first, for example, an unsubstituted aliphatic group having 1 to 10 carbon atoms, an unsubstituted aromatic group having 6 to 12 carbon atoms, or 5 to 5 carbon atoms. 12 unsubstituted alicyclic groups.

  Examples of the unsubstituted aliphatic group having 1 to 10 carbon atoms include methyl, ethyl, propyl, hexyl, and decyl. Examples of the unsubstituted aromatic group having 6 to 12 carbon atoms include phenyl, naphthyl, and biphenyl; Examples of the unsubstituted alicyclic group having 5 to 12 carbon atoms include cyclopentyl and cyclohexyl.

（式（ｃ）中、Ｒ^４は炭素数２〜１０のアルキレン、フェニレンまたはナフチレンである。） As the monovalent hydrocarbon residue, secondly, for example, a group represented by the following formula (c),

(In formula (c), R ⁴ is alkylene having 2 to 10 carbon atoms, phenylene or naphthylene.)

（式（ｄ）中、Ｒ^５は炭素数１〜１０のアルキル基、フェニル基またはナフチル基である。） A group represented by the following formula (d):

(In formula (d), R ⁵ represents an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a naphthyl group.)

（式（ｅ）中、Ｒ^４およびＲ^５の定義は上記に同じであり、Ｒ^６は水素原子またはＲ^５に定義された基のいずれかである。） A group represented by the following formula (e):

(In formula (e), the definitions of R ⁴ and R ⁵ are the same as above, and R ⁶ is either a hydrogen atom or a group defined for R ^5. )

（式（ｆ）中、Ｒ^４およびＲ^６の定義は上記に同じであり、Ｒ^７は水素原子またはＲ^５に定義された基のいずれかである。）
を挙げることができる。 Substituted aliphatic or aromatic residues represented by the following formula (f)

(In formula (f), the definitions of R ⁴ and R ⁶ are the same as above, and R ⁷ is either a hydrogen atom or a group defined for R ^5. )
Can be mentioned.

As the monovalent hydrocarbon residue, thirdly, the unsubstituted aromatic residue is substituted with the same substituent as exemplified as the substituent of the aromatic residue representing X ¹ , for example. You can list what you have. Therefore, examples of substitution with such a substituent include tolyl, methylnaphthyl, nitrophenyl, nitronaphthyl, chlorophenyl, benzoylphenyl, acetylphenyl, and acetylnaphthyl.

  As the monovalent hydrocarbon residue, a group represented by the above formula (c), (d), (e) or (f), that is, a substituted aliphatic residue or aromatic residue, in particular, a substituted one thereof. Aromatic residues are preferred.

  As the divalent hydrocarbon residue (when n = 2), first, for example, a divalent, unsubstituted aliphatic residue having 2 to 10 carbon atoms, or an unsubstituted aromatic having 6 to 12 carbon atoms. Group residues and unsubstituted alicyclic residue groups having 5 to 12 carbon atoms.

  Examples of the divalent unsubstituted aliphatic group having 2 to 10 carbon atoms include ethylene, trimethylene, tetramethylene, decamethylene and the like. Examples of the divalent unsubstituted aromatic residue having 6 to 12 carbon atoms include, for example, Examples of the divalent unsubstituted alicyclic residue having 5 to 12 carbon atoms include cyclopentylene and cyclohexylene.

  As the divalent hydrocarbon residue, secondly, for example, a substituted aliphatic residue or aromatic residue represented by the following formula (g) or the following formula (h) can be exemplified.

（式（ｇ）中、Ｒ^８はＲ^４に定義された基のいずれかである。）

(In formula (g), R ⁸ is any of the groups defined for R ^4. )

（式（ｈ）中、Ｒ^８の定義は上記に同じであり、Ｒ^９はＲ^４に定義された基のいずれかであり、そしてＲ^１０はＲ^６に定義された基のいずれかである。）

(In formula (h), the definition of R ⁸ is the same as above, R ⁹ is any of the groups defined for R ⁴ , and R ¹⁰ is any of the groups defined for R ^6. .)

As the divalent hydrocarbon residue, thirdly, the unsubstituted divalent aromatic residue is, for example, the same substituent as exemplified as the substituent of the aromatic group representing X ¹ above. Mention may be made of substituted ones.

When n is 2, R ¹ is preferably a direct bond or an unsubstituted or substituted divalent aromatic hydrocarbon residue of the first to third groups, particularly two Preferred are the first or third group of unsubstituted or substituted aromatic hydrocarbon residues with the bond from the furthest position, especially P-phenylene, P, P′-biphenylene or 2,6 Naphthylene is preferred.

  Examples of the trivalent hydrocarbon residue (when n = 3) include a trivalent aromatic residue having 6 to 12 carbon atoms.

かかる芳香族残基は、上記１価の芳香族残基の置換基として例示したと同じ置換基で置換されていてもよい。 Examples of such aromatic residues include the following.

Such an aromatic residue may be substituted with the same substituent as exemplified as the substituent of the monovalent aromatic residue.

In the above general formula (I), R ² and R ³ are the same or different and are monovalent hydrocarbon residues, and X ² is a tetravalent aromatic hydrocarbon residue.
Examples of R ² and R ³ include the same groups as those exemplified for R ^{1 in} the case of n = 1 in the description of the formula (I).

（ここで、Ｒの定義は式（ａ）に同じ。） Examples of the tetravalent aromatic hydrocarbon residue include groups represented by the following.

(Here, the definition of R is the same as in formula (a).)

The tetravalent aromatic residue may be substituted with the same substituent as exemplified as the substituent of the monovalent aromatic residue representing R ¹ in the description of the formula (I).
Specific examples of the cyclic imino ester represented by the above formulas (I) and (II) used in the present invention include the following compounds.

(Compound of the above formula (I))
(Compound when n = 1)
2-methyl-3,1-benzoxazin-4-one, 2-butyl-3,1-benzoxazin-4-one, 2-phenyl-3,1-benzoxazin-4-one, 2- (1- Or 2-naphthyl) -3,1-benzoxazin-4-one, 2- (4-biphenyl) -3,1-benzoxazin-4-one, 2-p-nitrophenyl-3,1-benzoxazine- 4-one, 2-m-nitrophenyl-3,1-benzoxazin-4-one, 2-p-benzoylphenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1 -Benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazin-4-one, 2-cyclohexyl-3,1-benzoxazin-4-one, 2-p- (or m-) Phthal Midophenyl-3,1-benzoxazin-4-one, N-phenyl-4- (3,1-benzoxazin-4-one-2-yl) phthalimide, N-benzoyl-4- (3,1-benzoxazine -4-on-2-yl) aniline, N-benzoyl-N-methyl-4- (3,1-benzoxazin-4-on-2-yl) aniline, 2- (p- (N-methylcarbonyl) Phenyl) -3,1-benzoxazin-4-one.

(Compound when n = 2)
2,2′-bis (3,1-benzoxazin-4-one), 2,2′-ethylenebis (3,1-benzoxazin-4-one), 2,2′-tetramethylenebis (3 1-benzoxazin-4-one), 2,2′-decamethylenebis (3,1-benzoxazin-4-one), 2,2′-p-phenylenebis (3,1-benzoxazine-4-one) ON), 2,2′-m-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one) ), 2,2 ′-(2,6- or 1,5-naphthylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2-methyl-p-phenylene) bis (3 , 1-benzoxazin-4-one), 2,2 ′-(2-nitro-p-phenylene) (3,1-benzoxazin-4-one), 2,2 ′-(2-chloro-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(1, 4-cyclohexylene) bis (3,1-benzoxazin-4-one), Np- (3,1-benzoxazin-4-one-2-yl) phenyl, 4- (3,1-benzoxazine -4-on-2-yl) phthalimide, Np- (3,1-benzoxazin-4-on-2-yl) benzoyl, 4- (3,1-benzoxazin-4-on-2-yl) ) Aniline.

(Compound when n = 3)
1,3,5-tri (3,1-benzoxazin-4-on-2-yl) benzene, 1,3,5-tri (3,1-benzoxazin-4-on-2-yl) naphthalene, 2,4,6-tri (3,1-benzoxazin-4-one-2-yl) naphthalene

(Compound of the above formula (II))
2,8-dimethyl-4H, 6H-benzo (1,2-d; 5,4-d ′) bis (1,3) -oxazine-4,6-dione, 2,7-dimethyl-4H, 9H— Benzo (1,2-d; 4,5-d ′) bis (1,3) -oxazine-4,9-dione, 2,8-diphenyl-4H, 8H-benzo (1,2-d; 5, 4-d ') bis (1,3) -oxazine-4,6-dione, 2,7-diphenyl-4H, 9H-benzo (1,2-d; 4,5-d') bis (1,3 ) -Oxazine-4,6-dione, 6,6′-bis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-bis (2-ethyl-4H, 3) 1-benzoxazin-4-one), 6,6′-bis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-methylenebis 2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-ethylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′- Butylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-butylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′- Oxybis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-oxybis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′- Sulfonylbis (2-methyl-4H, 3,1-ben Oxazin-4-one), 6,6′-sulfonylbis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-carbonylbis (2-methyl-4H, 3,1) -Benzoxazin-4-one), 6,6'-carbonylbis (2-phenyl-4H, 3,1-benzoxazin-4-one), 7,7'-methylenebis (2-methyl-4H, 3 1-benzoxazin-4-one), 7,7′-methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 7,7′-bis (2-methyl-4H, 3, 1-benzoxazin-4-one), 7,7′-ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-oxybis (2-methyl-4H, 3) , 1-benzoxazin-4-one), 7,7′- Sulfonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-carbonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7 ′ -Bis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7'-bis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,7 ' -Methylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7'-methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one).

  Among the above exemplified compounds, compounds of the above formula (I), more preferably compounds of the above formula (I) when n = 2, particularly preferably compounds of the following formula (I) -1 are used advantageously. .

（式中、Ｒ^１１は２価の芳香族炭化水素残基である。）

(In the formula, R ¹¹ is a divalent aromatic hydrocarbon residue.)

  Among the compounds of formula (I) -1, 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis ( 3,1-benzoxazin-4-one) and 2,2 ′-(2,6-naphthylene) bis (3,1-benzoxazin-4-one) are preferred.

  The ultraviolet absorption characteristics of these cyclic imino esters are described in, for example, Japanese Patent Application Laid-Open No. 59-12952 for representative compounds thereof, which are incorporated herein by reference.

  The cyclic imino ester has excellent compatibility with the polyester, but reacts with the terminal hydroxyl group of the polyester as described in JP-A-59-12952 and US Pat. No. 4,291,152. Have the ability. Therefore, it is required to carefully mix the cyclic imino ester and the polyester so that the cyclic imino ester is contained in a substantially unreacted state. However, in the case of using a polyester in which the main proportion of the terminal group is a carboxyl group or a polyester in which the terminal hydroxyl group is blocked with a terminal blocking agent that is not reactive with the cyclic imino ester, the cyclic imino ester is unreacted. No special care needs to be taken to produce the composition containing in the state. When using a polyester in which the main proportion of terminal groups is a hydroxyl group, the melt mixing time is preferably completed in a short time so as to satisfy the following formulas (1) and (2).

Logt ≦ −0.008T + 4.8 (1)
Tm <T <320 (2)
(In formulas (1) and (2), t is the melt mixing time (seconds), T is the melt mixing temperature (° C.), and Tm is the melting temperature (° C.) of the polyester.)

  In this case, there is a possibility that the cyclic imino ester and the polyester react with each other at a small ratio, but this reaction increases the molecular weight of the polyester. It is possible. When a cyclic imino ester reacts with polyester, the ultraviolet absorption wavelength region generally tends to shift to a lower wavelength side than the unreacted ultraviolet absorption wavelength region, and therefore tends to transmit ultraviolet light on the higher wavelength side. It has.

  These cyclic imino esters absorb light from the vicinity of 380 nm from ultraviolet rays, so there is no coloration on the film, and excellent properties for preventing the deterioration of the visible light absorber and film, while the periphery of the die in film formation, the stenter Contamination in the oven and the cause of defects due to adhesion of the recrystallized product of the sublimate to the film.

  The addition amount of the ultraviolet absorber is preferably 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, per 100% by weight of the polyester composition constituting the polyester film. If it is less than 0.1%, the effect of preventing UV deterioration is small, and if it exceeds 5% by weight, the film-forming characteristics of the polyester are lowered, which is not preferable.

  Examples of the method of adding the ultraviolet absorber to the polyester include a polyester polymerization step, kneading into a polymer in a melting step before film formation, and impregnation into a biaxially stretched film. Of these, kneading into the polymer in the melting step before film formation is preferable from the viewpoint of preventing a decrease in the degree of polymerization of the polyester. This kneading can be performed by, for example, a compound powder direct addition method or a master batch method.

[Easily adhesive layer]
In the present invention, an easy-adhesion polyester film is formed by providing an easy-adhesion layer made of a composition containing a polyester resin as a main component on a polyester film. The easy adhesion layer is provided on the polyester film as a coating layer by coating. The coating layer may be provided on one side or on both sides.
Hereinafter, the component which comprises an easily bonding layer is demonstrated.

[Polyester resin]
As the polyester resin, a polyester obtained from a dicarboxylic acid component and a diol component can be used. Examples of the polyvalent base component 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, A dimer acid and 5-sodium sulfo isophthalic acid can be illustrated.

  As the polyester resin, it is preferable to use a copolymerized polyester using two or more kinds of dicarboxylic acid components. The polyester resin may contain an unsaturated polybasic acid component such as maleic acid or itaconic acid, or a hydroxycarboxylic acid component such as p-hydroxybenzoic acid, if it is in a slight amount.

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

  The polyester resin preferably has a glass transition point of 40 to 130 ° C, more preferably 60 to 80 ° C. Within this range, excellent adhesion and scratch resistance can be obtained. On the other hand, if the glass transition temperature is less than 40 ° C., blocking tends to occur between the films, and if it exceeds 130 ° C., the coating film becomes hard and brittle, and scratch resistance is deteriorated.

The intrinsic viscosity of the polyester resin is 0.4 or more and less than 0.7, preferably 0.5 or more and less than 0.7. If it is this range, generation | occurrence | production of the low molecular weight substance from polyester resin itself can be suppressed, and since the cohesion force of polyester resin is high, the outstanding adhesiveness and scratch resistance can be obtained. If the intrinsic viscosity is less than 0.4, low molecular weight substances are generated from the polyester resin itself, which deteriorates the transparency of the substrate, which is not preferable.
The polyester resin is preferably soluble or dispersible in water, but water-soluble one containing some organic solvent can also be used.

This polyester resin can be produced, for example, by the following method. A dicarboxylic acid component and a diol component are charged into a transesterification reactor, a catalyst is added, methanol is distilled off by controlling the temperature at 230 ° C. in a nitrogen atmosphere, and a transesterification reaction is performed. Next, the temperature is gradually raised to 255 ° C., and the polycondensation reaction is carried out under reduced pressure in the system to obtain a polyester resin. When the molecular weight increases during the polycondensation, the melt viscosity increases and stirring in the system becomes difficult. The polyester resin used in the easy-adhesion layer has a high melt viscosity for a low molecular weight compared to homopolyethylene terephthalate, making stirring in the system very difficult, increasing the torque of the motor of the stirring equipment, and the shape of the blade Intrinsic viscosity can be increased by devising the above and by extending the polymerization time.
The ratio of the polyester resin in the easy adhesion layer is preferably 50 to 95% by weight, more preferably 60 to 90% by weight, per 100% by weight of the composition constituting the easy adhesion layer.

[Fine particles]
The easy adhesion layer preferably contains fine particles. The fine particles contained in the easy-adhesion layer are fine particles having an average particle diameter of preferably 20 to 200 nm, more preferably 40 to 120 nm. If it exceeds 200 nm, it is not preferable because fine particles easily fall off, and if it is less than 20 nm, sufficient lubricity and scratch resistance may not be obtained. The fine particles are usually contained in the composition of the easy adhesion layer.

  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 preferred.

[Crosslinking agent]
It is preferable to mix | blend a crosslinking agent with the composition of an easily bonding layer, and epoxy, oxazoline, melamine, and isocyanate are preferable as a crosslinking agent. One of these may be used, or two or more may be used.

  Examples of the epoxy crosslinking agent include a polyepoxy compound, a diepoxy compound, a monoepoxy compound, a glycidylamine compound and the like. Examples of the polyepoxy compound include sorbitol, polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, Examples of diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diepoxy compounds include neopentyl glycol diglycidyl ether, 1,6-hexanediol diester. Glycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol As diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, monoepoxy compound, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, 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 (Butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group) and the like (meth) acrylic acid esters; 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-dialkylmethacrylate (as alkyl groups, 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 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, 1,6-diisocyanate hexane, and adducts of tolylene diisocyanate and hexane triol. , Tolylene diisocyanate and trimethylolpropane adduct, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-vitrylene -4,4 'diisocyanate, 3,3' dimethyldiphenylmethane-4,4'-diisocyanate, metaphenylene diisocyanate and the like.

When the crosslinking agent is contained in the composition of the easy adhesion layer, the content of the crosslinking agent is preferably 0.1 to 30% by weight, more preferably 10 to 25% by weight per 100% by weight of the composition of the easy adhesion layer. is there. If it is less than 0.1% by weight, the cohesive strength of the coating film may not be exhibited, which is not preferable, and the adhesiveness may be insufficient. If it exceeds 30% by weight, the coating film becomes very hard, stress relaxation is reduced, adhesion is not exhibited, and when a coated film is collected and used, foreign matter due to a crosslinked product may be generated, which is not preferable.
As the crosslinking agent for the easy-adhesion layer, an oxazoline crosslinking agent is preferable from the viewpoints of ease of handling, pot life of the coating solution, and the like.

[Aliphatic wax]
The composition of the easy adhesion layer preferably contains an aliphatic wax. Specific examples of the aliphatic wax include plant waxes such as carnauba wax, candelilla wax, rice wax, wood wax, jojoba oil, palm wax, rosin-modified wax, olicuric wax, sugar cane wax, esparto wax, and bark wax. Animal waxes such as beeswax, lanolin, whale wax, ibota wax and shellac wax; mineral waxes such as montan wax, ozokerite and ceresin wax; petroleum waxes such as paraffin wax, microcrystalline wax and petrolactam; And synthetic hydrocarbon waxes such as polyethylene wax, oxidized polyethylene wax, polypropylene wax, and oxidized polypropylene wax. Among them, carnauba wax, paraffin wax, and polyethylene wax are particularly preferable because they are easy to adhere to hard coats and pressure-sensitive adhesives and have good lubricity. These are preferably used as an aqueous dispersion because they can reduce the environmental burden and are easy to handle.

  The content of the aliphatic wax is preferably 0.5 to 30% by weight, more preferably 1 to 10% by weight per 100% by weight of the composition of the easy adhesion layer. If the content is less than 0.5% by weight, the slipperiness of the film surface may not be obtained, which is not preferable. If it exceeds 30% by weight, adhesion to a polyester film substrate and easy adhesion to a hard coat or a pressure-sensitive adhesive may be insufficient, which is not preferable.

[Physical properties of film]
It is important that the easily adhesive polyester film for optics of the present invention has a melting subpeak temperature (Tsm) of 180 ° C. or higher and lower than 220 ° C., preferably 180 ° C. or higher and lower than 210 ° C., more preferably lower than 180 ° C. It is 200 degrees C or less. When the melting sub-peak temperature is less than 180 ° C., the film strength is insufficient, the handling property at the time of processing is poor, and the strength as an optical application member is insufficient. On the other hand, if the temperature is 220 ° C. or higher, the amount of adhered foreign matter on the film surface increases.
In order to obtain a film satisfying this melting subpeak temperature condition, the film may be produced under the stretching conditions shown in the film production method in the next section.

  Further, in the optically easy-adhesive polyester film of the present invention, the thermal shrinkage in the longitudinal direction when the film is heat-treated at 150 ° C. for 30 minutes is preferably 1.4% or less, more preferably 0.5% or less. . If the thermal shrinkage rate exceeds 1.4%, the film shrinks greatly during processing, and the hard coat layer coated on the film tends to be cracked, which is not preferable.

  The easily adhesive polyester film for optics in the present invention preferably has a haze of less than 3%. If the haze exceeds 3%, it is not preferable because it may not be suitable as an optical application such as a loss of visibility in various display applications.

[Film Production Method]
In order to obtain a film having a melting subpeak temperature (Tsm) of 180 ° C. or higher and lower than 220 ° C., the following stretching conditions may be taken.

  First, polyester is melt-extruded into a film shape, cooled and solidified with a casting drum to form an unstretched film, and then a coating solution is applied to form an easy-adhesion layer. The unstretched film is formed from Tg to (Tg + 60) of the film. The longitudinal direction and the width direction are simultaneously stretched at 6 to 25 times, preferably 10 to 20 times at 0 ° C., and further subjected to heat treatment (called heat setting) at 180 ° C. or more and less than 220 ° C. for 1 to 60 seconds. Preferably, re-heat treatment (referred to as relaxation treatment) is performed at a temperature lower by 10 to 20 ° C. than the heat setting temperature while shrinking by 0 to 20% in the longitudinal direction and / or the width direction. In this method, since the film is less likely to come into contact with the roll, minute scratches and the like are less likely to occur on the film surface than in the method described above, which is advantageous for application to optical applications. The glass transition temperature of the film is expressed as Tg. When the heat setting temperature is 220 ° C. or higher, the adhesion of foreign matters increases. On the other hand, when the heat setting temperature is lower than 180 ° C., the film becomes stiff and the handling property at the time of processing deteriorates, and the strength as an optical application member is insufficient.

  For example, when polyethylene terephthalate is used as the polyester, a preferable production method will be described. First, a coating solution is applied to a stretchable polyester film in order to form an easy-adhesion layer, followed by drying and stretching. The drying is preferably performed at a temperature of 90 to 130 ° C. for 2 to 10 seconds, and the stretching is preferably performed at a temperature of 90 to 130 ° C. 3 to 5 times in the longitudinal direction, 3 to 5 times in the transverse direction, and if necessary, the longitudinal direction 1 Perform under 3 times condition. Then, heat setting is performed while relaxing in the vertical and horizontal directions at a temperature of 180 ° C. or higher and lower than 220 ° C. for 2 to 20 seconds. The thickness of the obtained biaxially stretched film is preferably 50 to 350 μm, and the thickness of the coating film is preferably 0.02 to 1 μm.

  In the present invention, an easy-adhesion layer is applied to at least one surface of the polyester film. As described above, this is performed by applying a coating solution to form an easy-adhesion layer on a stretchable polyester film, and then drying. The film can be applied by stretching and heat treatment as necessary. The solid concentration of the coating liquid is usually 30% by weight or less, preferably 10% by weight or less.

  The stretchable polyester film is an unstretched polyester film, a uniaxially stretched polyester film, or a biaxially stretched polyester film. Of these, a longitudinally stretched polyester film uniaxially stretched in the extrusion direction (longitudinal direction) of the film is particularly preferable when the sequential stretching method is used, and an unstretched polyester film is particularly preferable among them when the simultaneous biaxial stretching method is used.

  When applying the coating liquid to the film, physical treatment such as corona surface treatment, flame treatment, plasma treatment, etc. is applied to the film surface as a pretreatment for improving the coatability, or it is chemically inert with the composition. It is preferable to use a surfactant in combination. Such a surfactant promotes the wettability of the aqueous coating liquid to the polyester film. For example, polyoxyethylene alkylphenyl ether, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, Examples include anionic and nonionic surfactants such as alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates. The surfactant is preferably contained in an amount of 1 to 10% by weight in the composition forming the coating film. If it is this range, it can be set to 40 mN / m or less, and the repellency of an easily bonding layer can be prevented.

  When applying a coating liquid to a polyester film, it is not preferable to carry out a normal coating process, that is, a biaxially stretched and heat-fixed polyester film in a process separated from the film manufacturing process, which easily entraps soot and dust. . From such a viewpoint, application in a clean atmosphere, that is, application in a film manufacturing process is preferable. And according to this application | coating, the adhesiveness to the polyester film of an easily bonding layer further improves.

As the 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 alone or in combination. The coating amount of the coating liquid is, for example, 0.5 to 20 g, preferably 1 to 10 g per 1 m ² of the running film. The coating liquid is preferably used as an aqueous dispersion or emulsion. In addition, a coating film may be formed only in the single side | surface of a film as needed, and may be formed in both surfaces.

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

(1) Melting sub-peak temperature (Tsm)
Using a DSC220 manufactured by Seiko Denshi Kogyo Co., Ltd., a DSC curve was drawn at a sample rate of 10 mg at a heating rate of 20 ° C./min. ).

(2) Heat shrinkage rate A sample of 350 mm in the longitudinal (MD) direction and 50 mm in the width direction of the film was cut out, marked at 300 mm intervals near both ends in the longitudinal direction of the sample, and placed in an oven adjusted to a temperature of 150 ° C. One end was fixed and the other end was left free for 30 minutes. The distance between the gauge points was measured in the take-out chamber (this length is assumed to be S), and the thermal contraction rate (MD heat yield) in the MD direction was determined by the following formula.
MD heat yield (%) = (300−S) / 300 × 100

(3) Number of adhered foreign substances The number of adhered foreign substances having a long side exceeding 0.1 mm was visually counted using halogen light in a dark room. Evaluation results per 1 m ^{2 of} film were evaluated according to the following criteria.
◎: Number of adhered foreign matter / 1 m ² <8 ○: 8 ≦ Number of adhered foreign matter / 1 m ² <15 ×: 15 ≦ Number of adhered foreign matter / 1 m ²

(4) Haze value The haze value of the film was measured using a haze meter (NDH-20) manufactured by Nippon Denshoku Industries Co., Ltd., and evaluated according to the following criteria.
◎: Haze value ≦ 1.5% …… Extremely good haze of film ○: 1.5% <Haze value ≦ 3.0% …… Good haze of film ×: 3.0% <Haze value …… Haze of film Bad

(5) Hard coat adhesion A 10 μm thick hard coat layer is formed on the surface of the easy-adhesive polyester film, and a cross cut (100 squares of 1 mm ² ) is applied on the hard coat layer. A cellophane tape having a width of 24 mm (manufactured by Nichiban Co., Ltd.) was 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.
5: Peeling area is less than 10% …… Adhesion is very good 4: Peeling area is 10% or more and less than 20% …… Adhesion is good 3: Peeling area is 20% or more and less than 30% …… Adhesion is slightly good 2: Peeling Area is 30% or more and less than 40% …… Adhesive strength is poor 1: Peeling area is over 40% …… Adhesive strength is extremely poor

[Examples 1 to 4 and Comparative Examples 1 and 2]
Polyethylene terephthalate (inherent viscosity: 0.62) containing 1% by weight of an ultraviolet absorber represented by the following formula (A) was melt-extruded on a rotating cooling drum maintained at 20 ° C. to obtain an unstretched film.

  Next, the unstretched film was stretched 3.4 times in the longitudinal direction, and then an aqueous coating solution having a concentration of 8% by weight of the coating composition shown in Table 1 was uniformly applied to both sides thereof using a roll coater.

    Polyester 1: The acid component is composed of 75 mol% of 2,6-naphthalenedicarboxylic acid / 20 mol% of isophthalic acid / 5 mol% of 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% of ethylene glycol / 10 mol% of diethylene glycol. (Tg = 80 ° C., average molecular weight 15000). Polyester 1 was produced as follows. That is, 51 parts of dimethyl 2,6-naphthalenedicarboxylate, 11 parts of dimethyl isophthalate, 4 parts of dimethyl 5-sodium sulfoisophthalate, 31 parts of ethylene glycol and 2 parts of diethylene glycol were charged into a reactor. 05 parts were added, the temperature was controlled at 230 ° C. in a nitrogen atmosphere, and the resulting methanol was distilled off to conduct a transesterification reaction. Next, the temperature of the reaction system was gradually raised to 255 ° C. in a polymerization kettle with high motor torque of the stirrer, and the inside of the system was reduced in pressure by 1 mmHg to carry out a polycondensation reaction to obtain polyester 1 having an intrinsic viscosity of 0.56. 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, and then this dispersion was subjected to a reduced pressure of 20 mmHg. Distilled and the tetrahydrofuran was distilled off. An aqueous dispersion of polyester 1 was obtained.

    Polyester 2: The acid component is composed of 95 mol% terephthalic acid / 5 mol% 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% ethylene glycol / 10 mol% diethylene glycol (Tg = 72 ° C., average molecular weight 16000). . Polyester 2 was produced as follows. A reactor was charged with 56 parts of dimethyl terephthalate, 5 parts of dimethyl 5-sodium sulfoisophthalate, 36 parts of ethylene glycol, and 3 parts of diethylene glycol, and 0.05 parts of tetrabutoxy titanium was added thereto, and the temperature was changed to 230 under a nitrogen atmosphere. The mixture was heated to a temperature of 0 ° 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, thereby obtaining polyester 2 having an intrinsic viscosity of 0.57. 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 2 was obtained.

Crosslinking agent 1: Consists of 30 mol% of methyl methacrylate / 2 mol% of 2-isopropenyl-2-oxazoline / 10 mol% of polyethylene oxide (n = 10) methacrylate / 30 mol% 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%.
Crosslinking agent 2: glycerol polyglycidyl ether (trade name Denacol EX-313, manufactured by Nagase ChemteX Corporation)

Fine particles 1: Composite inorganic particles of silica and titania (average particle size: 100 nm). The fine particles 1 were produced as follows according to the methods described in the production examples and examples of JP-A-7-2520. A glass reaction vessel with an inner volume of 4 liters equipped with a stirring blade was charged with 140 g of methanol, 260 g of isopropanol, and 100 g of aqueous ammonia (25% by weight) to prepare a reaction solution, and stirred while maintaining the temperature of the reaction solution at 40 ° C. did. Next, 542 g of silicon tetramethoxide (Si (OMe) ₄ , Colcoat Co., Ltd., trade name: methyl silicate 39) was charged into a 3 liter Erlenmeyer flask, and 195 g of methanol and 0.1 wt% hydrochloric acid were stirred. 28 g of an aqueous solution (35% hydrochloric acid, Wako Pure Chemical Industries, Ltd. diluted to 1/1000 with water) was added and stirred for about 10 minutes. Subsequently, a solution obtained by diluting 300 g of titanium tetraisopropoxide (Ti (Oi-Pr) 4, Nippon Soda Co., Ltd., product name: A-1 (TPT)) with 634 g of isopropanol was added, and a transparent uniform solution ( A co-condensate of silicon tetraalkoxide and titanium tetraalkoxide) was obtained. Each of 1699 g of the homogeneous solution and 480 g of aqueous ammonia (25% by weight) were simultaneously added dropwise to the reaction solution over 2 hours while initially decreasing the dropping speed and gradually increasing the speed toward the end. After completion of dropping, the obtained cohydrolyzate was filtered, the organic solvent was dried at 50 ° C., and then dispersed in water to obtain fine particles 1 having a concentration of 10% by weight.
Fine particles 2: Silica filler (average particle diameter 80 nm) (trade name Cataloid SI-80P, manufactured by Catalytic Chemical Industry Co., Ltd.)
Wax: Carnauba wax (trade name Cellosol 524, manufactured by Chukyo Yushi Co., Ltd.)
Wetting agent: Polyoxyethylene (n = 7) lauryl ether

  Next, this coated film was dried at 95 ° C., stretched 3.7 times at 120 ° C. in the transverse direction, and the biaxially stretched film was heat-set at the heat setting temperature described in Table 2 in the tenter as it was, Then, after separating both ends of the film from the clip with a carbide blade in the tenter, the film was relaxed by reducing the take-up speed by 1.4%, slowly cooled from 180 ° C. to 110 ° C., taken out from the tenter, and loosened by the end face nip roll. While supporting both ends of the product part, the film cooled to 90 ° C at room temperature is taken up by a take-up roller having a surface temperature of 65 ° C, conveyed by a plurality of roll groups without passing through a nip roller, wound up by a winder, and thickened. A highly adhesive polyester film having a thickness of 125 μm was obtained. The thickness of the coating film was 0.08 μm. The evaluation results are shown in Table 2. In Comparative Example 2, no coating film was applied.

[Example 5, Comparative Example 3]
After heat setting, an easy-adhesive polyester film was produced in the same manner as in Example 1 except that the both ends of the film were cooled with a carbide blade without separating from the clip, and the film was not loosened by reducing the take-off speed. The evaluation results are shown in Table 2.

[Example 6]
Polyethylene terephthalate (inherent viscosity: 0.62) containing 1% by weight of an ultraviolet absorber represented by the following formula (A) is extruded from a die, cooled by a cooling drum by a conventional method to form an unstretched film, and then displayed on both sides. An aqueous coating solution having a coating concentration of 6% shown in 1 was uniformly applied with a roll coater. The coated film was subsequently dried at 95 ° C., stretched at 100 ° C. at the same time in the longitudinal direction by 3.4 times and in the transverse direction by 3.6 times, and at 215 ° C., contracted by 2% in the longitudinal direction and the width direction, respectively. The polyester film having a thickness of 125 μm and an easily adhesive layer thickness of 0.08 μm was obtained. The evaluation results are shown in Table 2.

  As is apparent from the results shown in Table 2, the optically easy-adhesive polyester film of the present invention is excellent in adhesive strength, transparency and light resistance with functional layers used for optical applications such as PDP and LCD, and on the surface. It is useful as an easily adhesive polyester film for optics with a small number of defects due to the adhesion of foreign matter.

  The optically easy-adhesive polyester film of the present invention can be suitably used as a member used for optical applications such as PDP and LCD.

Claims (3)

  An optically easy-adhesive polyester film comprising a polyester film containing an ultraviolet absorber and an easy-adhesion layer provided thereon, and having a melting subpeak temperature (Tsm) of 180 ° C. or higher and lower than 220 ° C.   The easily adhesive polyester film for optics according to claim 1, which is produced by a simultaneous biaxial stretching method.   The easily adhesive polyester film for optics according to claim 1 or 2, which is used for a plasma display panel member or a liquid crystal display member.