JP2005097571A - Optical easy adhesive polyester film and optical laminated polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical easy adhesive polyester film which allows inhibition of rainbow color under a fluorescence lamp, and excellent in adhesiveness to a hard coat layer under a high temperature and a high humidity (heat and wet resistance). <P>SOLUTION: The optical easy adhesive polyester film is obtained by coating a water-based coating liquid on at least one side of a biaxially oriented polyester film, drying, and laminating an applying layer which is oriented toward at least one direction, wherein the water-based coating liquid contains a resin composition which is mainly composed of a water polyester resin (A) and at least one (B) of a soluble titanium chelate compound, a soluble titanium acylate compound, a soluble zirconium chelate compound, and a soluble zirconium acylate compound at an (A)/(B) mixing ratio (in mass ratio) of 10/90 to 95/5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is attached to the front surface of a display screen such as a touch panel, a liquid crystal display (LCD), a television or computer cathode ray tube (CRT), a plasma display (PDP), etc., and reflects external light, glare, and iris color. An optically-adhesive polyester film used as a base material for an antireflection film imparted with antireflection properties and a hard coat layer laminated on at least one side of a coating layer of the film. The present invention relates to a laminated polyester film.

  On the front surface of touch panels, computers, televisions, liquid crystal display devices, etc., decorative materials, etc., a hard coat layer made of electron beam, ultraviolet light or thermosetting resin is laminated on a base made of transparent plastic film Coated film is used. In addition, a transparent biaxially oriented polyester film is generally used as the transparent plastic film of the substrate, and in order to improve the adhesion between the polyester film of the substrate and the hard coat layer, these intermediate layers can be easily used. In many cases, an adhesive layer can be provided.

  The hard coat film is required to have temperature, humidity, light durability, transparency, chemical resistance, scratch resistance, antifouling property, and the like. Moreover, since a hard coat film is used for a display, a decoration material, etc., visibility and designability are requested | required. Therefore, in order to suppress glare and iris-like color caused by reflected light when viewed from an arbitrary angle, the antireflection of a multilayer structure in which a high refractive index layer and a low refractive index layer are laminated on top of the hard coat layer. It is common practice to provide a layer.

  However, in recent years, applications such as displays and decorative materials have been required to have a larger screen (larger area) and higher quality, and accordingly, the required level for suppressing iris-like colors (interference fringes) especially under fluorescent lamps. Is getting higher. In addition, fluorescent lamps have become a three-wavelength type for daylight color reproducibility, and interference fringes are more likely to occur. Further, there is an increasing demand for cost reduction by simplifying the antireflection layer. Therefore, it is demanded to suppress interference fringes as much as possible even with a hard coat film alone.

  The iris color of the hard coat film (interference fringes) is the difference between the refractive index of the base polyester film (eg 1.62 for PET) and the refractive index of the hard coat layer (eg 1.49 for acrylic resin). It is thought to occur because of the large. In order to reduce the difference in refractive index and prevent the occurrence of interference fringes, a method for increasing the refractive index of the hard coat layer by adding metal oxide fine particles to the hard coat layer is disclosed (for example, (See Patent Document 1). However, the addition of metal oxide fine particles to the hard coat layer lowers the original functions of the hard coat layer, such as transparency, chemical resistance, scratch resistance, and antifouling properties. Further, when an antireflection layer is further provided on the hard coat layer, it is necessary to optimize the antireflection layer in accordance with the change in the refractive index of the hard coat layer.

  In addition, as another method for suppressing interference fringes in the hard coat layer, paying attention to the variation in the local thickness of the film, after manufacturing an easy-adhesive film, the film is subjected to a calendering treatment to determine the local thickness of the film. A method for reducing the variation in the above has been disclosed (for example, see Patent Document 2). However, the above method evaluates the interference fringes by the film alone, and no investigation is made on the interference fringes based on the difference in the refractive index of the interface when the hard coat layer is laminated, and the production increases because the number of processes increases. There is a problem in terms of sex.

  Moreover, the invention which prescribed | regulated the area ratio of the interference fringe paying attention to the thickness unevenness of the layer which comprises a hard-coat film is disclosed (for example, refer patent document 3). However, the level of thickness spots and the reduction method are not specifically described in the specification. For example, in order to reduce the thickness unevenness of each layer, it is necessary to strictly control the thickness of each layer, which is problematic in terms of productivity or yield.

  Furthermore, focusing on the back surface reflectance of the film itself, a method of laminating a hard coat layer having a specific hardness while suppressing the back surface reflectance is also disclosed (see, for example, Patent Document 4). However, in the method described in Patent Document 4, a coat layer having a specific refractive index and a specific thickness is provided on the opposite surface of the hard coat layer of the hard coat film, and the back surface reflectance is controlled to be 0.1% or less. Must. Therefore, it is necessary to design the film including the back side. In addition, when the film is manufactured, the back surface reflectivity is always controlled to 0.1% or less, and the back surface reflectivity is controlled such as changing the condition when the back surface reflectivity is out of the range while measuring the back surface reflectivity. It is complicated.

JP-A-7-151902 JP 2001-71439 A JP 2002-241527 A JP 2002-210906 A

  An object of the present invention is to provide an optically easy-adhesive polyester film that suppresses iris-like color under a fluorescent lamp and is excellent in adhesion to a hard coat layer and adhesion in high temperature and high humidity (wet heat resistance) and An object of the present invention is to provide an optical laminated polyester film obtained by laminating a specific hard coat layer on the film.

  In the present invention, paying attention to the refractive index of the easy-adhesion layer, the easy-adhesion layer so that the refractive index difference between the polyester film of the base material and the easy-adhesion layer and the refractive index difference between the easy-adhesion layer and the hard coat layer are reduced. By controlling the refractive index of the easy-adhesion layer with the type and content of the resin and additives that make up the resin, while maintaining adhesion to the hard coat layer and adhesion under high temperature and high humidity (moisture heat resistance) The inventors have found that the iris-like color under a fluorescent lamp can be suppressed.

  That is, the present invention provides an aqueous polyester resin (A) and a water-soluble titanium chelate compound, a water-soluble titanium acylate compound, a water-soluble zirconium chelate compound, or a water-soluble polyester resin on at least one side of a biaxially stretched polyester film. An aqueous coating solution comprising a resin composition having a main component of at least one zirconium acylate compound (B) and a mixing ratio (mass ratio) of (A) / (B) of 10/90 to 95/5 After being coated and dried, it is an optically easy-adhesive polyester film obtained by laminating a coating layer stretched in at least one direction. Moreover, it is a laminated polyester film for optics formed by laminating a hard coat layer made of an electron beam, an ultraviolet curable acrylic resin, or a siloxane-based thermosetting resin on at least one surface of the coating layer of the easily adhesive polyester film.

  The optically easy-adhesive polyester film of the present invention is excellent in antireflection properties for suppressing reflection of external light, glare, iris color, etc. when a hard coat layer is laminated on the easy-adhesive layer of the film, and Excellent adhesion to hard coat layer and adhesion under high temperature and high humidity (moisture heat resistance).

(Base film)
The biaxially stretched polyester film used as a substrate in the present invention is a film composed of a polyester resin, and mainly contains at least one of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate as a constituent component. Among these polyester resins, polyethylene terephthalate is most preferable from the balance between physical properties and cost. Moreover, a polyester film can improve chemical resistance, heat resistance, mechanical strength, etc. by biaxially stretching.

  The biaxially stretched polyester film may be a single layer or a multilayer. These layers can contain various additives in the polyester resin as necessary. Examples of the additive include an antioxidant, a light-resistant agent, an anti-gelling agent, an organic lubricant, an antistatic agent, an ultraviolet absorber, and a surfactant.

  In addition, in order to improve the handling properties such as film slipperiness, rollability and blocking resistance, and wear characteristics such as abrasion resistance and scratch resistance, inert particles are generally added to the polyester film of the base material. It is included. However, since the film of the present invention is used as a base film for an optical member, it is required to have excellent handling properties while maintaining high transparency. Specifically, when used as an optical member, the transparency is preferably such that the total light transmittance of the easily adhesive polyester film is 85% or more, and particularly preferably 90% or more. The higher the total light transmittance is, the better the transparency is (100% is ideal), but the handling property is lowered and the production at the industrial level becomes difficult. Therefore, the upper limit of the total light transmittance is preferably 96%.

  Therefore, the content of the inert particles in the base film is preferably as small as possible. Therefore, it is preferable to make a multilayer structure in which particles are contained only in the surface layer of the film, or to contain fine particles only in the coating layer without substantially containing particles in the film.

  In particular, from the viewpoint of transparency, when inert particles are not substantially contained in the polyester film, inorganic and / or heat-resistant polymer particles are contained in the aqueous coating solution in order to improve the handleability of the film. It is important to form irregularities on the surface of the coating layer. Note that “substantially no inert particles” means, for example, in the case of inorganic particles, a content which is below the detection limit when quantitatively analyzing the elements derived from the particles by fluorescent X-ray analysis. Means.

    In the easily adhesive polyester film of the present invention, the coating layer comprises an aqueous polyester resin (A), a water-soluble titanium chelate compound, a water-soluble titanium acylate compound, a water-soluble zirconium chelate compound, or a water-soluble zirconium acylate. It consists of a resin composition in which at least one compound (B) is a main constituent and the mixing ratio (mass ratio) of (A) / (B) is 10/90 to 95/5.

  This resin composition is heated with heat during the stretching process of the base film, so that at least one of a titanium chelate compound, a titanium acylate compound, a zirconium chelate compound, or a zirconium acylate compound (B) is a polyester resin. A uniform film is formed by the crosslinking reaction. That is, since the metal chelate compound or metal acylate compound is decomposed by heat treatment, it does not exist in the coating layer in a state where it is added to the coating solution.

Therefore, the content of the metal chelate compound or metal acylate compound in the coating solution is calculated from the content of the metal element (Ti or Zr) in the coating layer after the heat treatment as follows.
(1) First, the type of chelate or acylate contained in the coating solution is identified from the chelate or acylate residue in the coating layer.
(2) Next, the content of the metal chelate compound or metal acylate compound in the coating solution is calculated from the content of the metal element (Ti or Zr) in the coating layer.

The refractive index of the coating layer is higher than that of the polyester resin (A) alone by increasing the composition ratio of at least one of the titanium chelate compound, the titanium acylate compound, the zirconium chelate compound, or the zirconium acylate compound (B). Can also be high.
Increasing the refractive index of the coating layer can also be achieved by including metal fine particles, but by including the metal fine particles, the stretchability of the coating layer and the adhesion between the hard coat layer and the base film are descend.

  In the polyester resin (A) used in the present invention, an active site such as a hydroxyl group or a carboxyl group may be introduced into the molecular chain. A cross-linking reaction takes place in this place, resulting in a dense film.

  Moreover, in order to give the same crosslinkability with an acrylic resin, it is necessary to introduce a crosslinkable functional group. However, since the refractive index of the acrylic resin itself is low, even when a titanium chelate compound, a titanium acylate compound, a zirconium chelate compound, or a zirconium acylate compound is used in combination, the refractive index is controlled to be the same as that of the coating layer of the present invention. It is difficult.

  Furthermore, since the polyester resin (A), which is a constituent component of the coating layer, is involved in adhesion to the base polyester film, the composition ratio (A / B) between the aqueous polyester resin (A) and the compound (B) is When the ratio is less than 10/90, the adhesion to the base film is lowered, and the stretchability as the coating layer is lowered, and it is not uniform at the time of stretching. Therefore, the transparency required for optical use decreases, and the adhesion with the hard coat layer formed on the easy-adhesion layer becomes a problem. On the other hand, when the composition ratio (A / B) between the aqueous polyester resin (A) and the compound (B) exceeds 95/5, a water-soluble titanium acylate compound, a water-soluble zirconium chelate compound, or a water-soluble Crosslinking by the zirconium acylate compound (B) becomes poor, and the refractive index also decreases. For this reason, the adhesion (humidity and heat resistance) under high temperature and high humidity is lowered, and the effect of suppressing iris-like colors under a fluorescent lamp is insufficient.

  The aqueous polyester resin (A) of the present invention is dissolved or dispersed in water or a water-soluble organic solvent (for example, an aqueous solution containing less than 50% by mass of alcohol, alkyl cellosolve, ketone, or ether). Means a polyester resin capable of In order to impart water resistance to the polyester resin, it is important to introduce a hydrophilic group such as a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, or an ether group into the molecular chain of the polyester resin. Among the hydrophilic groups, sulfonic acid groups are preferable from the viewpoint of coating film properties and adhesion.

  When the sulfonic acid group is introduced into the polyester, the sulfonic acid compound is more preferably 1 to 10 mol% in the total acid component of the polyester. When the amount of the sulfonic acid group is less than 1 mol%, the polyester resin does not exhibit water, and a water-soluble titanium chelate compound, a water-soluble titanium acylate compound, a water-soluble zirconium chelate compound, or a water-soluble zirconium acylate compound Since the compatibility with at least one of (B) also decreases, it becomes difficult to obtain a uniform and transparent coating layer. Moreover, when the amount of sulfonic acid group exceeds 10 mol%, it becomes easy to be inferior to the adhesiveness (humidity heat resistance) under high temperature and high humidity.

  Further, the aqueous polyester resin (A) preferably has a glass transition temperature of 40 ° C. or higher. For this reason, the acid component of the polyester resin (A) is preferably composed mainly of an aromatic group such as terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid. Moreover, as a glycol component, aromatics, such as glycol with comparatively few carbon numbers, such as ethylene glycol, propane glycol, 1, 4- butanediol, neopentyl glycol, or the ethylene oxide addition product of bisphenol A, are preferable. Further, as a raw material of the polyester resin (A), a rigid component such as biphenyl or a dicarboxylic acid component or diol component having a high refractive index atom such as bromine or sulfur may be used within a range in which the physical properties of the film do not deteriorate. Good. When the glass transition temperature of the polyester resin (A) is less than 40 ° C., the adhesiveness (humidity heat resistance) under high temperature and high humidity tends to be insufficient. Furthermore, since the refractive index of the polyester resin (A) also decreases, the refractive index of the coating layer also decreases. As a result, the suppression of iris color under fluorescent lamps tends to be insufficient.

  The other main component of the coating layer is at least one (B) of a water-soluble titanium chelate compound, a water-soluble titanium acylate compound, a water-soluble zirconium chelate compound, or a water-soluble zirconium acylate compound. The above water-soluble means to dissolve in water or an aqueous solution containing less than 50% by mass of a water-soluble organic solvent.

  Examples of water-soluble titanium chelate compounds include diisopropoxybis (acetylacetonato) titanium, isopropoxy (2-ethyl-1,3-hexanediolato) titanium, diisopropoxybis (triethanolaminato) titanium, di -N-butoxybis (triethanolaminato) titanium, hydroxybis (lactato) titanium, ammonium salt of hydroxybis (lactato) titanium, titanium beloxocitrate ammonium salt and the like.

  Examples of the water-soluble titanium acylate compound include oxotitanium bis (monoammonium oxalate), and examples of the water-soluble zirconium compound include zirconium tetraacetylacetonate and zirconium acetate.

  In the coating layer, a resin other than the main component, for example, an acrylic resin, a polyurethane resin, a polyester resin, an alkyd resin, a vinyl resin such as polyvinyl alcohol, etc. is used in a range that does not affect the effect of the present invention. It doesn't matter. Further, the combined use of the crosslinking agent is not particularly limited as long as the effect of the present invention is not affected. Examples of crosslinking agents that can be used include adducts of urea, melamine, benzoguanamine, and the like with formaldehyde, amino resins such as alkyl ether compounds composed of these adducts and alcohols having 1 to 6 carbon atoms, polyfunctional epoxy compounds, Examples thereof include a polyfunctional isocyanate compound, a blocked isocyanate compound, a polyfunctional aziridine compound, and an oxazoline compound.

  In the present invention, the coating liquid used for forming the coating layer includes an aqueous polyester resin (A), a water-soluble titanium chelate compound, a water-soluble titanium acylate compound, a water-soluble zirconium chelate compound, or a water-soluble It is an aqueous coating liquid mainly composed of at least one zirconium acylate compound (B) and an aqueous solvent. When applying the above aqueous coating solution to the surface of the polyester film, an appropriate amount of a known anionic surfactant or nonionic surfactant is added to improve the wettability of the film and coat the coating solution uniformly. It is preferable to do.

  In addition, in the aqueous coating solution, inorganic and / or heat-resistant polymer particles, antistatic agents, ultraviolet absorbers, etc. in order to impart other functions such as handling properties, antistatic properties and antibacterial properties to the film. Additives such as organic lubricants, antibacterial agents, and photo-oxidation catalysts can be included.

  As the solvent used in the coating solution, alcohols such as ethanol, isopropyl alcohol, and benzyl alcohol may be mixed in addition to water in a range of less than 50% by mass with respect to the total coating solution. Furthermore, if it is less than 10 mass%, you may mix in the range which can melt | dissolve organic solvents other than alcohol. However, the total amount of alcohols and other organic solvents in the coating solution is preferably less than 50% by mass.

  The laminated polyester film for optics of the present invention is obtained by providing a hard coat layer made of an electron beam, an ultraviolet curable acrylic resin, or a siloxane-based thermosetting resin on at least one surface of the coating layer of the easily adhesive polyester film. .

  Resin that is cured by electron beam or ultraviolet ray, has acrylate functional group, for example, relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin , Oligomers or prepolymers of polyfunctional compounds such as polybutadiene resins, polythiol polyene resins, polyhydric alcohols, etc., and reactive diluents such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, Monofunctional monomers such as N-vinylpyrrolidone and polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate , Diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, etc. Things can be used.

  However, in the case of an ultraviolet curable resin, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethyltyrium monosulfide, thioxanthones, As a photosensitizer, n-butylamine, triethylamine, tri-n-butylphosphine and the like can be mixed and used.

(Manufacture of easily adhesive polyester film)
The production method of the easily adhesive polyester film of the present invention will be described by taking a polyethylene terephthalate (hereinafter abbreviated as PET) film as an example, but is not limited to this.

  After sufficiently drying the PET resin in a vacuum, it is supplied to an extruder, melted and extruded at about 280 ° C. from a T-die into a rotating cooling roll into a sheet, cooled and solidified by an electrostatic application method, and unstretched PET. Get a sheet. The unstretched PET sheet may have a single layer structure or a multilayer structure by a coextrusion method. Moreover, it is preferable not to contain an inert particle substantially in PET resin.

  The obtained unstretched PET sheet is stretched 2.5 to 5.0 times in the longitudinal direction with a roll heated to 80 to 120 ° C. to obtain a uniaxially stretched PET film. Furthermore, the edge part of a film is hold | gripped with a clip, it guide | induces to the hot air zone heated at 70-140 degreeC, and is extended | stretched 2.5 to 5.0 times in the width direction. Then, it guide | induces to the heat processing zone of 160-240 degreeC, and heat-processes for 1 to 60 seconds, and completes crystal orientation.

  In any stage of the film production process, the aqueous coating solution is applied to at least one surface of the PET film. The coating layer may be formed on both sides of the PET film. The solid content concentration of the resin composition in the aqueous coating solution is preferably 2 to 35% by mass, particularly preferably 4 to 15% by mass.

As a method for applying this aqueous coating solution to a PET film, any known method can be used. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. These methods are applied alone or in combination.
In the present invention, it is important that the coating layer is formed by applying the aqueous coating solution to an unstretched or uniaxially stretched PET film, drying it, stretching it at least uniaxially, and then performing a heat treatment. The film coated with the coating solution is guided to a tenter and heated for transverse stretching and heat treatment. At that time, the chelate compound or the acylate compound can form a stable crosslinked coating layer by a thermal crosslinking reaction. On the other hand, in the case of a coating layer obtained by applying and drying the above-mentioned coating solution on a biaxially stretched PET film, the amount of heat is suppressed in order to reduce the deterioration of the transparency of the substrate film due to heat treatment and the change in physical properties. I have to. Therefore, the amount of heat is insufficient to perform the thermal crosslinking reaction, and a uniform crosslinked coating layer cannot be formed.

In the present invention, the coating amount of the finally obtained coating layer is preferably 0.02 to 0.5 g / m ² . If the coating amount of the coating layer is less than 0.02 g / m ² , not only the effect on adhesiveness is almost lost, but also the effect of suppressing iris-like colors under a fluorescent lamp tends to be insufficient. On the other hand, when the coating amount exceeds 0.5 g / m ² , the effect of suppressing the iris color under a fluorescent lamp tends to be insufficient.

  The coating layer of the easily adhesive polyester film obtained in the present invention has not only good adhesion to a hard coat layer made of an electron beam or an ultraviolet curable acrylic resin or a siloxane thermosetting resin, but also optical Good adhesive strength can be obtained for purposes other than the intended use. Specifically, adhesion such as photographic photosensitive layer, diazo photosensitive layer, matte layer, magnetic layer, inkjet ink receiving layer, hard coat layer, UV curable resin, thermosetting resin, printing ink and UV ink, dry laminate, extrusion laminate, etc. Examples thereof include vacuum deposition, electron beam deposition, sputtering, ion plating, CVD, plasma polymerization and the like of an agent, a metal or an inorganic substance, or an oxide thereof, and an organic barrier layer.

(Manufacture of laminated polyester film for optics)
The method for producing an optical laminated polyester film of the present invention will be described by taking a PET film as an example, but is not limited to this.

  A coating liquid for forming a hard coat layer containing the electron beam, the ultraviolet curable acrylic resin, or the siloxane thermosetting resin is applied to at least one surface of the easy-adhesive polyester film. The coating solution need not be diluted, but may be diluted with an organic solvent according to the viscosity, wettability, coating layer thickness, etc. of the coating solution. After applying the hard coat layer-forming coating solution on the coating layer on at least one side of the easy-adhesive polyester film, the hard coat layer is dried as necessary, and in accordance with the curing conditions of the curable resin, The hard coat layer is formed by curing the coating layer by irradiating with electron beam or ultraviolet light and heating.

In the present invention, the thickness of the hard coat layer is preferably 1 to 15 μm. When the thickness of the hard coat layer is less than 1 μm, the effects on the chemical resistance, scratch resistance, antifouling property and the like as the hard coat layer are almost lost. On the other hand, if the thickness exceeds 15 μm, the flexibility of the hard coat layer is reduced, and the possibility of cracks and the like increases.
The optically laminated polyester film obtained in the present invention can be used for a wide range of applications. In particular, by forming an antireflection layer on the hard coat layer, a good antireflection film can be obtained. For the formation of such an antireflection layer, a single layer of an inorganic material such as ZnO, TiO ₂ , CeO ₂ , SnO ₂ , ZrO ₂ or the like having a high refractive index or MgF ₂ or SiO ₂ having a low refractive index or a metal material is used. Alternatively, it is performed by providing multiple layers. These layers are formed as a single layer or multiple layers of an application layer made of a resin composition containing vapor deposition, sputtering, plasma CVD, or the like, or a high refractive index or low refractive index inorganic material or metal material.

  EXAMPLES Next, although this invention is demonstrated in detail using an Example and a comparative example, naturally this invention is not limited to a following example. The evaluation method used in the present invention is as follows.

(1) Total light transmittance Based on JIS K7105, the total light transmittance of the film was calculated | required using the turbidimeter (Nippon Denshoku Industries Co., Ltd. make, NDH2000).

(2) Glass transition temperature Based on JIS K7121, using a differential scanning calorimeter (Seiko Instruments Co., Ltd., DSC6200), the temperature was raised at a rate of 20 ° C / min over a temperature range of 25-300 ° C, and from the DSC curve The obtained extrapolated glass transition start temperature was defined as the glass transition temperature.

(3) Adhesiveness A hard coat film is determined according to JIS-K5400 8.5.1, and the adhesiveness between the hard coat layer and the substrate film is determined.

Specifically, 100 grid-like cuts that penetrate the hard coat layer and reach the base film are made on the hard coat layer surface using a cutter guide having a gap interval of 2 mm. Next, a cellophane adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) is attached to the grid-shaped cut surface and rubbed with an eraser to be completely attached. Then, the cellophane adhesive tape is peeled off vertically from the hard coat layer surface of the hard coat film, and the number of squares peeled off from the hard coat layer surface of the hard coat film is visually counted. Seeking adhesion with In addition, what has peeled partially among squares is counted as a square which peeled.
Adhesiveness (%) = (1−number of peeled squares / 100) × 100

(4) Moisture and heat resistance The hard coat film was left in an environment of 60 ° C. and 95 RH% for 500 hours in a high-temperature and high-humidity tank, and then the hard coat film was taken out and left at room temperature for 12 hours.
Thereafter, the adhesion between the hard coat layer and the substrate film was determined in the same manner as in (3) above, and ranked according to the following criteria.
A: 100%
○: 96% or more and less than 100% △: 80% or more and less than 96% ×: less than 80%

(5) Interference fringe improvement (iris color)
The hard coat film was cut into an area of 10 cm (film width direction) × 15 cm (film longitudinal direction) to prepare a sample film. A black glossy tape (manufactured by Nitto Denko Corporation, vinyl tape No. 21; black) was bonded to the surface opposite to the hard coat layer surface of the obtained sample film. With the hard coat surface of the sample film as the top surface, the positional relationship where the reflection is the strongest visually observed from diagonally above using a three-wavelength daylight white color (National Palook, FL 15EX-N 15W) as a light source (distance 40 to distance from the light source) (60 cm, angle of 15 to 45 °).

The results of visual observation are ranked according to the following criteria. The observation is performed by five people who are familiar with the evaluation, and the highest rank is the evaluation rank. If two ranks have the same number, the center of the rank divided into three is adopted. For example, ◎ and ○ are 2 people each and △ is 1 person, ○ is ◎, ◎ is 1 person and ○ and △ are 2 people each, ○, ◎ and △ are 2 people each and ○ is 1 In the case of names, ○ is adopted.
◎: Iridescent colors are not observed even when observed from all angles. ○: Some iris colors are observed at some angles. △: Slightly iris colors are observed. X: Clear iris colors are observed. Be done

(Polyester resin polymerization)
In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 186 parts by mass of dimethyl terephthalate, 186 parts by mass of dimethyl isophthalate, 23.7 parts of dimethyl 5-sodium sulfoisophthalate, 137 of neopentyl glycol Mass parts, 191 parts by mass of ethylene glycol, and 0.5 parts by mass of tetra-n-butyl titanate were charged, and a transesterification reaction was performed from 160 ° C. to 220 ° C. over 4 hours. Next, the temperature was raised to 255 ° C., and the pressure of the reaction system was gradually reduced, followed by reaction for 1 hour 30 minutes under a reduced pressure of 29 Pa to obtain a copolymerized polyester resin (A-1). The obtained copolyester resin was light yellow and transparent.

  In the same manner, copolymer polyester resins (A-2, A-3, A-4) having different compositions were obtained. Table 1 shows the results of the composition and weight average molecular weight measured by NMR for these copolyester resins.

Example 1
(1) Preparation of polyester aqueous dispersion In a reactor equipped with a stirrer, a thermometer and a reflux device, 20 parts by mass of polyester resin (A-1) and 15 parts by mass of ethylene glycol monobutyl ether are added and heated at 100 ° C. , Stirred to dissolve the resin. After the resin was completely dissolved, 65 parts by mass of water was gradually added to the polyester solution while stirring. After the addition, the solution was cooled to room temperature while stirring to prepare an aqueous dispersion (B-1) of milky white polyester having a solid content of 20% by mass. Similarly, using the polyester resins (A-2) to (A-4) instead of the polyester resin (A-1), an aqueous dispersion was prepared, and the aqueous dispersions (B-2) to (B-) were respectively obtained. 4).

(2) Preparation of coating liquid 40 parts by mass of the obtained polyester aqueous dispersion (B-1), 44 parts by mass of hydroxybis (lactato) titanium (manufactured by Matsumoto Pharmaceutical Co., Ltd., TC310) 18 parts by mass, water 150 1 part by mass of anionic surfactant (Naoperex No6F powder, manufactured by Kao Corporation) and colloidal silica fine particles (manufactured by Catalytic Chemical Industry, Cataloid) SI80P (average particle size 80 nm) 2% by mass of an aqueous dispersion as silica was added to the resin solid content to prepare a coating solution (hereinafter abbreviated as coating solution (C-1)).

(3) Manufacture of an easily adhesive polyester film having a coating layer As a film raw material polymer, PET resin pellets having an intrinsic viscosity of 0.62 dl / g and substantially free of particles are 135 ° C. under a reduced pressure of 133 Pa. And dried for 6 hours. Thereafter, it is supplied to a twin-screw extruder, melted and extruded into a sheet form at about 280 ° C., rapidly cooled and solidified by an electrostatic application method on a rotating cooling metal roll maintained at a surface temperature of 20 ° C. A stretched PET sheet was obtained.

  This unstretched PET sheet was heated to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a difference in peripheral speed to obtain a uniaxially stretched PET film.

Next, the coating solution (C-1) was coated on one side of the PET film by a reverse roll method so that the coating amount after drying was 0.5 g / m ^2, and then dried at 80 ° C. for 20 seconds. After drying, the film was stretched 4.0 times in the width direction at 120 ° C with a tenter, and heated at 230 ° C for 0.5 seconds with the length in the width direction fixed, and further at 230 ° C. A relaxation treatment in the width direction of 3% was performed for 10 seconds to obtain a biaxially stretched PET film having a coating layer on one side having a thickness of 100 μm.

(4) Production of Hard Coat Film 5 parts by mass of methyl ethyl ketone is added to 5 parts by mass of hard coat agent (manufactured by Dainichi Seika Co., Ltd., Seika Beam EXF01 (B); solid content 100% by mass) on the surface of the easy-adhesive polyester film. The added solution was applied using a # 8 wire bar and dried at 70 ° C. for 1 minute to remove the solvent. Next, the hard coat layer surface was irradiated with ultraviolet rays under the conditions of irradiation energy of 200 mJ / cm ² and irradiation distance of 15 cm using a high pressure mercury lamp while the film coated with the hard coat layer was run at a feeding speed of 5 m / min. A hard coat film having a hard coat layer of 3 μm was obtained. The evaluation results are shown in Table 2.

Example 2
48 parts by mass of polyester aqueous dispersion (B-2), 44 parts by mass of hydroxybis (lactato) titanium (manufactured by Matsumoto Pharmaceutical Co., Ltd., TC310) 15 parts by mass, 150 parts by mass of water and 100 parts by mass of isopropyl alcohol Further, an anionic surfactant (Kao Co., Ltd., Neopelex No6F powder) is added in an amount of 1% by mass with respect to the coating solution, colloidal silica fine particles (catalyst chemical industry, Cataloid SI80P; average particle size 80 nm) in water dispersion. Was added in an amount of 2% by mass as silica with respect to the resin solid content to prepare a coating solution (hereinafter abbreviated as coating solution (C-2)). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 3
Polyester aqueous dispersion (B-3) 12 parts by mass, diisopropoxybis (triethanolaminato) titanium 80% by mass solution (manufactured by Matsumoto Pharmaceutical Co., Ltd., TC400) 17 parts by mass, water 150 parts by mass and isopropyl alcohol 100 parts by mass were mixed, and anionic surfactant (Neopelex No6F powder, manufactured by Kao Corporation) was 1% by mass with respect to the coating liquid, colloidal silica fine particles (catalyst chemical industry, Cataloid SI80P; average particle size) 80 nm) An aqueous dispersion was added in an amount of 2% by mass as silica with respect to the resin solid content to prepare a coating solution (hereinafter abbreviated as coating solution (C-3)). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 4
24 parts by weight of polyester aqueous dispersion (B-4), 11 parts by weight of diisopropoxybis (acetylacetonate) titanium, 150 parts by weight of water and 100 parts by weight of isopropyl alcohol were mixed, respectively, and an anionic surfactant ( 1% by mass of Neoperex No6F powder made by Kao Corporation and 2% by weight of colloidal silica fine particles (catalyst chemical industry, Cataloid SI80P; average particle size of 80 nm) as a silica with respect to the resin solid content. % Was added to prepare a coating solution (hereinafter abbreviated as coating solution (C-4)). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 5
32 parts by mass of a polyester aqueous dispersion (B-4), 10 parts by mass of zirconium acetate, 150 parts by mass of water and 100 parts by mass of isopropyl alcohol were mixed, and an anionic surfactant (Neopelex No6F powder manufactured by Kao Corporation) was mixed. ) 1% by mass with respect to the coating solution, and 2% by mass of colloidal silica fine particles (catalyst chemical industry, Cataloid SI80P; average particle size 80 nm) aqueous dispersion as silica with respect to the resin solid content was prepared to prepare a coating solution. (Hereinafter abbreviated as coating solution (C-5)). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 1
80 parts by mass of polyester aqueous dispersion (B-1), 150 parts by mass of water and 100 parts by mass of isopropyl alcohol are mixed, and an anionic surfactant (Naopelex No6F powder, manufactured by Kao Corporation) is used as a coating liquid. On the other hand, 1% by mass of colloidal silica fine particles (catalyst chemical industry, Cataloid SI80P; average particle size of 80 nm) was added in an amount of 2% by mass as silica with respect to the resin solids to prepare a coating solution (hereinafter referred to as coating solution ( Abbreviated as C-6)). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 2
64 parts by mass of an aqueous polyester dispersion (B-1), 10 parts by mass of a self-crosslinking polyurethane resin having a blocked isocyanate group (Daiichi Kogyo Seiyaku Co., Ltd., Elastron H-3), an elastron catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat 64) ) 1 part by mass, further 1% by weight of anionic surfactant (Naopelex No6F powder, manufactured by Kao Corporation), and colloidal silica fine particles (catalyst chemical industry, Cataloid SI80P; average particle size 80 nm) water The dispersion was added in an amount of 2% by mass as silica with respect to the resin solids to prepare a coating solution (hereinafter abbreviated as coating solution (C-7)). Using this coating solution, a biaxially stretched PET film having a coating layer on one side and a hard coat film were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 3
A 44% by mass solution of hydroxybis (lactato) titanium (manufactured by Matsumoto Pharmaceutical Co., Ltd., TC310) 40 parts by mass, 150 parts by mass of water and 100 parts by mass of isopropyl alcohol were mixed, respectively, and an anionic surfactant (Kao Corporation) 1% by mass of Neoperex No6F powder) and 2% by mass of colloidal silica fine particles (catalyst SI 80P; average particle size 80 nm) in water dispersion as silica with respect to the resin solids. Then, a coating solution was prepared (hereinafter abbreviated as coating solution (C-8)). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 4
32 parts by mass of a polyester aqueous dispersion (B-2), 5 parts by mass of a self-crosslinking polyurethane resin having a blocked isocyanate group (Daiichi Kogyo Seiyaku Co., Ltd., Elastoron H-3), an elastotron catalyst (Daiichi Kogyo Seiyaku Co., Ltd., Cat 64) ) 0.5 parts by weight, niobium oxide 10% by weight aqueous solution (manufactured by Taki Chemical Co., Ltd., SAM-0) 64 parts by weight, and further an anionic surfactant (Kao Corporation, Neopelex No6F powder). 1% by mass with respect to the liquid, and 2% by mass of an aqueous dispersion of colloidal silica fine particles (catalyst SI 80P; average particle size of 80 nm) as a silica with respect to the solid content of the resin was added to prepare a coating liquid (hereinafter referred to as coating). Liquid (C-9)). Using this coating solution, a biaxially stretched PET film having a coating layer on one side and a hard coat film were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 5
Acrylic resin emulsion having a solid content of 20% by mass (methyl methacrylate / ethyl acrylate / acrylic acid / N-methylolacrylamide = 60/40/2/4; mass ratio), 80 parts by mass, di-n-butoxybis (triethanolaminato) ) 3.2 parts by weight of titanium, 150 parts by weight of water and 100 parts by weight of isopropyl alcohol were mixed, and an anionic surfactant (Naopelex No6F powder, manufactured by Kao Corporation) was added in an amount of 1% by weight, respectively. Colloidal silica fine particles (Catalyst Kasei Kogyo Co., Ltd., Cataloid SI80P; average particle size 80 nm) aqueous dispersion was added in an amount of 2% by mass as silica to the resin solids to prepare a coating solution (hereinafter referred to as coating solution (C-10)). Abbreviated). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 6
Acrylic resin emulsion having a solid content of 20% by mass (methyl methacrylate / ethyl acrylate / acrylic acid / N-methylolacrylamide = 25/75/4/2: mass ratio) 48 parts by mass, titanium-modified aqueous resin (Matsumoto Pharmaceutical Co., Ltd.) 6.4 parts by mass, ORGATICS WS680), 150 parts by mass of water and 100 parts by mass of isopropyl alcohol are mixed, and an anionic surfactant (manufactured by Kao Corporation, Neopelex No6F powder) is added to the coating solution. 1% by mass, colloidal silica fine particles (catalyst chemical industry, Cataloid SI80P; average particle size 80 nm) in water dispersion was added in an amount of 2% by mass as silica with respect to the resin solids to prepare a coating solution (hereinafter referred to as coating solution (C -11)). Using this coating solution, a biaxially stretched PET film and a hard coat film having a coating layer on one side were obtained in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 7
An uncoated biaxially stretched PET film was obtained in the same manner as in Example 1 except that the easy-adhesion layer-forming coating solution was not used. A hard coat film having a hard coat layer formed on one side of the uncoated film in the same manner as in Example 1 was prepared. The evaluation results are shown in Table 2.

Comparative Example 8
90 parts by mass of water is added to 10 parts by mass of ultrafine titanium oxide particles (Itohara Sangyo Co., Ltd., TTO-S-1) having a particle diameter (width / length) of 0.01-0.02 μm / 0.05-0.1 μm as observed with an electron microscope. In addition, an aqueous dispersion A of titanium oxide particles having a concentration of 10% by mass was prepared by dispersing for 30 minutes at 5000 rpm with a disperser (AUTO CELL MASTER CM-200).
Next, 30 parts by mass of polyester aqueous dispersion (B-4), 150 parts by mass of water and 100 parts by mass of isopropyl alcohol are mixed, and an anionic surfactant (Naopelex No6F powder manufactured by Kao Corporation) is further applied as a coating solution. The polyester aqueous dispersion B was prepared by adding 1% by mass with respect to the aqueous solution. 30 parts by mass of the aqueous dispersion A of titanium oxide particles prepared as described above was added to the aqueous dispersion B of polyester to prepare a coating solution. However, since the titanium oxide fine particles became a gel and settled in the coating solution, application to the base film was stopped.

  The optically easy-adhesive polyester film of the present invention is excellent in antireflection properties for suppressing reflection of external light, glare, iris color, etc. when a hard coat layer is laminated on the easy-adhesive layer of the film, and Touch panel, liquid crystal display (LCD), television and computer cathode ray tube (CRT), plasma display (PDP), decoration materials, etc., because it has excellent adhesion with the hard coat layer and adhesion under high temperature and high humidity (moisture and heat resistance) It is suitable as a base film for an antireflection film that is attached to the front surface of the display screen and imparts antireflection properties to suppress the reflection of external light, glare, iris color, and the like. Furthermore, since it is excellent in adhesion with the layer coated with the easy-adhesion layer and adhesion under high temperature and high humidity (moisture and heat resistance), it is a hard coat layer used in optical applications as a layer coated with the easy-adhesion layer. Not only photographic photosensitive layer, diazo photosensitive layer, matte layer, ink layer, adhesive layer, thermosetting resin layer, UV curable resin layer, metal or inorganic oxide deposition layer, etc. Can also be used.

Claims (5)

  On at least one side of the biaxially stretched polyester film, at least one of the water-based polyester resin (A) and a water-soluble titanium chelate compound, a water-soluble titanium acylate compound, a water-soluble zirconium chelate compound, or a water-soluble zirconium acylate compound. After applying and drying an aqueous coating solution containing a resin composition having a mixing ratio (mass ratio) of (A) / (B) of 10/90 to 95/5, with 1 type (B) as the main constituent An optically easy-adhesive polyester film obtained by laminating a coating layer stretched in at least one direction.   The optically easy-adhesive polyester film according to claim 1, wherein the easy-adhesive polyester film has a total light transmittance of 85% or more.   The aqueous polyester resin (A) is a copolyester resin containing 1 to 10 mol% of an aromatic dicarboxylic acid component containing a sulfonic acid metal base with respect to the total dicarboxylic acid component of the polyester. Item 3. An easily adhesive polyester film for optics according to item 1 or 2.   The said water-based polyester resin (A) is 40 degreeC or more in glass transition temperature, The easily adhesive polyester film for optics in any one of Claims 1-3 characterized by the above-mentioned.   A hard coat layer made of an electron beam, an ultraviolet curable acrylic resin, or a siloxane-based thermosetting resin is laminated on at least one surface of the optically easy-adhesive polyester film coating layer according to claim 1. Optical laminated polyester film.