KR20210080619A - Easily-adhesive polyester film - Google Patents

Abstract

[Problem] The present invention is excellent in all of the low coherence that can suppress rainbow discoloration, the adhesion to the hard coat layer etc. required at a high level in various optical applications, the blocking resistance, and the transparency, and furthermore, it has high sliding properties It is to provide an easily-adhesive polyester film which can be suitably used in the optical use excellent in handling property at the time of manufacture or a post process, such as a polarizing plate manufacturing process of a liquid crystal display device.
[Solutions] The present invention has, on at least one side of the polyester film, an application layer containing a polyurethane resin having a polycarbonate skeleton and a polyester resin having a naphthalene skeleton, wherein the total solid content of the application layer is 100% by mass When the content a of the polyurethane resin component in this case, the content b of the polyester resin component having a naphthalene skeleton, and the total amount c of components other than these are shown in the triangular diagram, a, b, and c are four specific straight lines. An easily adhesive polyester film within the enclosed area is provided.

Description

Easily adhesive polyester film {EASILY-ADHESIVE POLYESTER FILM}

The present invention can secure the low coherence that can solve the problem of rainbow spots, and the adhesiveness with various functional layers, the anti-blocking property, and the easily-adhesive polyester excellent in transparency It's about film. In more detail, it is related with the easily adhesive polyester film which can be used suitably also in high-definition optical use.

The hard coat film which laminated|stacked the transparent hard-coat layer is used for front surfaces, such as a display of a touch panel, a computer, a television, and a liquid crystal display device, and a decorative material. In addition, as the transparent plastic film of the substrate, a transparent polyester film is generally used, and in order to improve the adhesion between the polyester film of the substrate and the hard coat layer, it has easy adhesion as an intermediate layer thereof. A coating layer is often installed.

The above hard coat film is required to have durability against temperature, humidity, light, transparency, chemical resistance, scratch resistance, antifouling properties, and the like. Moreover, since it is used for surfaces, such as a display and a decoration material, in many cases, visibility and designability are calculated|required. Therefore, in order to suppress glare or iris-like color due to reflected light when viewed from an arbitrary angle, a high refractive index layer and a low refractive index layer are stacked on top of the hard coat layer. It is generally practiced to provide an antireflection layer.

However, in applications such as displays and decorative materials, a further large screen (large area) and high definition are required in recent years, and with it, the required level for suppression of iris-like color (interference unevenness), especially under fluorescent lamps, is increasing. is rising In addition, the three-wavelength type of fluorescent lamps has become mainstream for the reproducibility of daylight color, and interference irregularities are more likely to appear. Moreover, the cost reduction request|requirement by the simplification of an antireflection layer is also increasing. Therefore, it is calculated|required to suppress an interference unevenness as much as possible only with the hard coat film to which an antireflection layer is not added.

In addition, with the development of mobile technology, the use of portable devices such as mobile phones, car navigation systems, and electronic books in outdoor areas is expanding. In addition, most of the said portable devices are a display by a liquid crystal panel from the point of thinning. In such a field, for example, in a mobile phone equipped with a touch panel, as a hard coat film for surface protection of a display, interference fringes caused by reflected light from both interfaces in contact with the coated surface or hard coat film such as an icon sheet In the use of giving designability to the back surface, the fault of visibility due to an interference fringe is becoming more present.

The iris-like color (interference unevenness) of the hard coat film has a large difference between the refractive index of the polyester film (for example, 1.62 to 1.65) and the refractive index (for example, 1.49) of the hard coat layer made of an acrylic resin or the like. It is said to occur because In order to reduce the refractive index difference between laminations and prevent the occurrence of interference spots, a relatively high refractive index coating layer is provided on the polyester film of the substrate, and the refractive index difference between the polyester film and the coating layer, the coating layer and the hard coat layer A method of reducing the refractive index difference of

Conventionally, in the field of an easily adhesive film for optics, as a method of raising the refractive index of an easily adhesive layer, the method of including specific high refractive index microparticles|fine-particles in an application layer, the method of raising the refractive index of resin of an application layer, etc. are known. In particular, the polyester resin using naphthalenedicarboxylic acid as a copolymerization component is excellent also in adhesiveness with a base material polyester film, and is proposed as a suitable example (for example, refer patent document 1). However, in general, a polyester resin having a high refractive index has a high glass transition temperature and is poor in adhesiveness, possibly because of insufficient flexibility of the resin, or when the amount of polyester resin is increased, blocking resistance may deteriorate. . On the other hand, a method of using a polyurethane resin having a polycarbonate component as a resin having excellent flexibility and high adhesion has been proposed (for example, refer to Patent Document 2), and also in Patent Document 1, a polyurethane resin having a polycarbonate component is blended. However, when the polyurethane component was increased, there was a problem that low coherence and transparency deteriorated. Thus, conventionally, the easily adhesive polyester film which has all of adhesiveness with a hard-coat layer, blocking resistance, and transparency in high balance, meeting the low coherence of the recent high level was not obtained.

Japanese Patent Laid-Open No. 2011-246663 Japanese Patent Laid-Open No. 2011-168053

This invention was made|formed against the subject of such prior art. That is, the object of the present invention is excellent in any of the low coherence that can suppress rainbow spots, the adhesion to the hard coat layer etc. required at a high level in various optical applications, the blocking resistance, and the transparency, and furthermore, the high It is to provide the easily adhesive polyester film which has sliding property and can be used suitably in the optical use excellent in the handling property in the post process, such as the time of manufacture and a polarizing plate manufacturing process of a liquid crystal display device.

That is, this invention consists of the following structures.

1. Polyurethane resin component in the case of having an application layer containing the polyurethane resin which has a polycarbonate frame|skeleton, and the polyester resin which has a naphthalene frame|skeleton on at least single side|surface of a polyester film, and the solid content of an application layer is 100 mass % When the content (mass %) of is a, the content (mass %) of the polyester resin component having a naphthalene skeleton is b, and the total amount (mass %) of components other than these is c, a, b , c is an easily-adhesive polyester film in a region surrounded by four straight lines: straight line P1, straight line Q1, straight line R1, and straight line S1.

Here, the straight line P1, the straight line Q1, the straight line R1, and the straight line S1 are as follows.

Straight line P1: a straight line passing through a point where a is 10 mass%, b is 55 mass%, and c is 35 mass%, and a is 10 mass%, b is 10 mass%, and c is 80 mass%

Straight line Q1: a straight line passing through a point where a is 10 mass%, b is 10 mass%, and c is 80 mass%, and a is 70 mass%, b is 10 mass%, and c is 20 mass%

Straight line R1: a straight line passing through a point where a is 70 mass%, b is 10 mass%, and c is 20 mass%, and a is 50 mass%, b is 40 mass%, and c is 10 mass%

Straight line S1: a straight line passing through a point where a is 45 mass%, b is 45 mass%, and c is 10 mass%, and a is 10 mass%, b is 55 mass%, and c is 35 mass%

2. The easily-adhesive polyester film of said 1st in which an application layer contains a crosslinking agent.

3. Said 1st or 2nd easily adhesive polyester film in which an application layer contains the metal oxide particle (particle A) of refractive index 1.7 or more.

4. The easily-adhesive polyester film in any one of said 1st - 3rd in which an application layer contains lubricant particle (particle B).

5. One or more functions selected from the group consisting of a hard coat layer, an anti-glare layer, an anti-glare anti-reflection layer, an anti-reflection layer, and a low-reflection layer on the application layer of the easily-adhesive polyester film according to any one of the first to fourth A laminated polyester film having a layer.

By this invention, it is excellent in the low coherence property, transparency, blocking resistance, adhesiveness with various functional layers, and sliding property which can suppress rainbow_pattern|erythema, and can use it suitably in an optical use of the easily adhesive polyester film of provided was possible.

BRIEF DESCRIPTION OF THE DRAWINGS It is a triangular diagram which shows the preferable range in the easily adhesive polyester film of this invention.

(polyester film)

The polyester film used as the base material in the present invention is a film composed of a polyester resin, and mainly comprises at least one of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate as a constituent component. Ester films are preferred. Moreover, the film which consists of co-polyester by which the 3rd component monomer was copolymerized to the above polyester may be sufficient. Among these polyester films, a polyethylene terephthalate film is the most preferable from the balance of a physical property and cost.

Moreover, even if said polyester film is a single|mono layer or a multilayer, it is not cared about. Moreover, as long as it exists in the range which shows the effect of this invention, each of these layers can be made to contain various additives in a polyester resin as needed. Examples of the additive include antioxidants, light resistance agents, gelling inhibitors, organic wetting agents, antistatic agents, ultraviolet absorbers, surfactants, and the like.

(coating layer)

As for the easily adhesive polyester film of this invention, the easily adhesive application layer is laminated|stacked on the base film made from the above polyester.

In the application layer in the present invention, the content (mass%) of the polyurethane resin component having a polycarbonate skeleton when the total amount (solid content) of the application layer is 100% by mass is a, a polyester resin component having a naphthalene skeleton. When the content (mass %) is b and the total amount (mass %) of other components is c, and expressed as a triangular diagram, a, b, and c are four straight lines: a straight line P1, a straight line Q1, a straight line R1, and a straight line S1. It is preferable that it is within the range of the area|region surrounded by .

Here, the straight line P1, the straight line Q1, the straight line R1, and the straight line S1 are the following.

Straight line P1: a straight line passing through a point where a is 10 mass%, b is 55 mass%, and c is 35 mass%, and a is 10 mass%, b is 10 mass%, and c is 80 mass%

Straight line Q1: a straight line passing through a point where a is 10 mass%, b is 10 mass%, and c is 80 mass%, and a is 70 mass%, b is 10 mass%, and c is 20 mass%

Straight line R1: a straight line passing through a point where a is 70 mass%, b is 10 mass%, and c is 20 mass%, and a is 50 mass%, b is 40 mass%, and c is 10 mass%

Straight line S1: a straight line passing through a point where a is 45 mass%, b is 45 mass%, and c is 10 mass%, and a is 10 mass%, b is 55 mass%, and c is 35 mass%

By setting it as the said range, low coherence (interference pattern improvement property), adhesiveness, blocking resistance, and transparency can all be maintained at a well-balanced and high level.

The above preferred range will be briefly described using the triangular diagram shown in FIG. 1 . On the three sides of the triangular diagram, the content a (mass %) of the polyurethane resin component having a polycarbonate skeleton, the content b (mass %) of the polyester resin component having a naphthalene skeleton, and the coordinate axes of the other components c (mass %) are respectively shown. Here, assuming that the coordinates inside the triangular diagram are written and expressed in the order of (a, b, c), there are five coordinates (10, 55, 35), (10, 10, 80), (70, 10, 20), (50, 40, 10) and (45, 45, 10) are shown. And, a straight line P1 passing through (10, 55, 35) and (10, 10, 80), a line Q1 passing through (10, 10, 80) and (70, 10, 20), (70, 10, 20) ) and a straight line R1 passing through (50, 40, 10), and a straight line S1 passing through (45, 45, 10) and (10, 55, 35) are shown, and are surrounded by the four straight lines. The inner range represents a range in which low coherence (interference pattern improvement), adhesiveness, blocking resistance, and transparency can be provided in a good balance.

In addition, the range more preferable for each straight line is described below.

Instead of the straight line P1, the straight line P2 (a is 15 mass%, b is 55 mass%, c is 30 mass%, a is 15 mass%, b is 10 mass%, c is 75 mass%, It is preferable to employ a straight line passing through it.

Instead of straight line Q1, straight line Q2 (a is 10 mass%, b is 20 mass%, c is 70 mass%, a is 70 mass%, b is 10 mass%, c is 20 mass% straight line passing through), further straight Q3 (a is 20 mass%, b is 20 mass%, c is 60 mass%, a is 70 mass%, b is 10 mass%, c is 20 mass% It is preferable to employ a straight line passing through

Instead of straight line R1, straight line R2 (a is 65 mass%, b is 10 mass%, c is 25 mass%, a is 45 mass%, b is 40 mass%, c is 15 mass% straight line passing through), further straight line R3 (a is 60 mass%, b is 10 mass%, c is 30 mass%, a is 40 mass%, b is 40 mass%, c is 20 mass% It is preferable to employ a straight line passing through

Instead of straight line S1, straight line S2 (a is 50 mass%, b is 40 mass%, c is 10 mass%, a is 10 mass%, b is 50 mass%, c is 40 mass%, straight line passing through), further straight line S3 (a is 52 mass%, b is 38 mass%, c is 10 mass%, a is 10 mass%, b is 48 mass%, c is 42 mass% straight line passing through), especially S4 (a is 55 mass%, b is 35 mass%, c is 10 mass%, a is 10 mass%, b is 45 mass%, c is 45 mass% It is preferable to employ a straight line passing through it.

Preferably the lower limit of content a of the polyurethane resin component which has polycarbonate frame|skeleton is 10 mass %, More preferably, it is 13 mass %, More preferably, it is 15 mass %. Transparency is not impaired as content a of the polyurethane resin component which has polycarbonate frame|skeleton is 10 mass % or more, adhesiveness is satisfied and it is preferable.

The upper limit of content a of the polyurethane resin component which has a polycarbonate skeleton becomes like this. Preferably it is 70 mass %, More preferably, it is 60 mass %, More preferably, it is 50 mass %, Especially preferably, it is 40 mass %. If content a of the polyurethane resin component which has polycarbonate frame|skeleton is 70 mass % or less, since refractive index is maintained high and low coherence is acquired, it is preferable.

Preferably the lower limit of content b of the polyester resin component which has a naphthalene skeleton is 10 mass %, More preferably, it is 15 mass %, More preferably, it is 20 mass %. If content b of the polyester resin component which has a naphthalene skeleton is 10 mass % or more, adhesiveness is satisfied and it is preferable.

The upper limit of content b of the polyester resin component which has a naphthalene skeleton becomes like this. Preferably it is 55 mass %, More preferably, it is 50 mass %, More preferably, it is 48 mass %, Especially preferably, it is 45 mass %. Blocking resistance is exhibited as content b of the polyester resin component which has naphthalene skeleton is 55 mass % or less, and it is preferable.

The lower limit of the content c of the other components is preferably 10 mass%, more preferably 20 mass%, still more preferably 25 mass%, and particularly preferably 30 mass%. If the content c of other components is 10 mass % or more, when the component which raises the refractive index of an application layer is contained, low coherence improves and it is preferable. Moreover, since content a of the polyurethane resin which has polycarbonate frame|skeleton does not increase too much as a result and blocking can be prevented, it is preferable.

The upper limit of content c of other components becomes like this. Preferably it is 80 mass %, More preferably, it is 70 mass %, More preferably, it is 60 mass %, Especially preferably, it is 55 mass %. If the content c of other components is 80 mass % or less, as a result, it is easy to balance the content a of the polyurethane resin component having a polycarbonate skeleton and the content b of the polyester resin component having a naphthalene skeleton, and adhesion is maintained, It is easy to balance blocking resistance and refractive index (low coherence), and it is preferable.

(Polyurethane resin having polycarbonate skeleton)

It is preferable to make the diol component which is a structural component of the polyurethane resin which has a polycarbonate backbone contain the aliphatic polycarbonate polyol excellent in heat resistance and hydrolysis resistance. In the optical use of this invention, it is preferable to use the aliphatic polycarbonate polyol also from the point of yellowing prevention.

As an aliphatic polycarbonate polyol, although an aliphatic polycarbonate diol, an aliphatic polycarbonate triol, etc. are mentioned, Preferably, an aliphatic polycarbonate diol can be used. As an aliphatic polycarbonate diol which is a component of the urethane resin of the present invention, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl -1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1 , An aliphatic polycarbonate diol obtained by reacting one or two or more of diols such as 4-cyclohexanedimethanol with carbonates such as dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc. can be heard

Polyurethane resin having a polycarbonate skeleton is an aliphatic polycarbonate component-derived ^{absorbance at 1460 cm -1} measured by infrared spectroscopy (A1460) and a urethane component-derived ^{absorbance near 1530 cm -1} (A1530) Ratio (A1460/ A1530) is preferably set to 0.40 to 2.30.

When the ratio (A1460/A1530) is 0.40 or more, the hard urethane component does not increase too much, the stress relaxation of the application layer does not fall, and there is no possibility that heat-and-moisture resistance may fall, and it is preferable. In addition, when the ratio (A1460/A1530) is 2.30 or less, the aliphatic component of the flexible aliphatic polycarbonate does not increase too much, and the solvent resistance of the coating layer is maintained, and there is no risk of deterioration in heat-and-moisture resistance, which is preferable.

In order to make the said ratio (A1460/A1530) into the range of 0.40-2.30, as a number average molecular weight of an aliphatic polycarbonate diol, Preferably it is 1500-4000, More preferably, it is 2000-3000. When the number average molecular weight of an aliphatic polycarbonate diol is small, the ratio of the aliphatic polycarbonate component which comprises a urethane resin becomes small relatively.

As polyisocyanate which is a component of the urethane resin of the present invention, for example, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate, 1,3- Alicyclic diisocyanates, such as bis (isocyanate methyl) cyclohexane, aliphatic diisocyanates, such as hexamethylene diisocyanate and 2,2,4-trimethyl hexamethylene diisocyanate, or these compounds singly or in plurality of trimethylolpropane and polyisocyanates added in advance to the like. Said polyisocyanate does not have a problem of yellowing, and is suitable for the object for which high transparency is calculated|required. Moreover, these polyisocyanates do not become too hard on a coating film, can relieve the stress by shrinkage|contraction and swelling of photocurable resin etc., and adhesiveness is maintained and it is preferable.

In order to impart water solubility to the urethane resin, a sulfonic acid (salt) group or a carboxylic acid (salt) group can be introduced (copolymerized) into the urethane molecular skeleton. A sulfonic acid (salt) group is strongly acidic, and since it may be difficult to maintain moisture resistance due to its moisture absorption performance, it is suitable to introduce|transduce a weakly acidic carboxylic acid (salt) group. Moreover, nonionic groups, such as a polyoxyalkylene group, can also be introduce|transduced.

In order to introduce a carboxylic acid (salt) group into the urethane resin, for example, as a polyol component, a polyol compound having a carboxylic acid group such as dimethylolpropionic acid or dimethylolbutanoic acid is introduced as a copolymerization component, and neutralized with a salt forming agent. . Specific examples of the salt forming agent include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, tri-n-butylamine, N-methylmorpholine, N- N-alkyl alkanolamines, such as N-alkyl morpholines, such as ethyl morpholine, N-dimethylethanolamine, and N-diethyl ethanolamine, are mentioned. These may be used independently and may use 2 or more types together.

In order to impart water solubility, when a polyol compound having a carboxylic acid (salt) group is used as a copolymerization component, the composition molar ratio of the polyol compound having a carboxylic acid (salt) group in the urethane resin is the total polyol component of the urethane resin. When it is set as 100 mol%, it is preferable that it is 3-60 mol%, and it is preferable that it is 5-40 mol%. When the said composition molar ratio is 3 mol% or more, water dispersibility is favorable and it is preferable. Moreover, when the said composition molar ratio is 60 mol% or less, since water resistance is maintained and heat-and-moisture resistance is maintained, it is preferable.

As for the glass transition point temperature of the urethane resin of this invention, less than 0 degreeC is preferable, More preferably, it is less than -5 degreeC. When the glass transition point temperature is less than 0°C, suitable flexibility is likely to be exhibited from the viewpoint of stress relaxation of the application layer, and it is preferable.

(Polyester resin having a naphthalene skeleton)

By containing a component derived from naphthalenedicarboxylic acid as an acid component of the polyester resin contained in the application layer, the refractive index increases and it becomes easy to control the iris-like color under a fluorescent lamp. Moreover, it becomes possible to improve heat-and-moisture resistance.

As such naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid is preferable. 20 mol% or more is preferable, as for the ratio of the said naphthalenedicarboxylic acid in all the dicarboxylic acid components which comprise a polyester resin, 30 mol% or more is more preferable, 50 mol% or more is still more preferable, 60 mol% or more It is more preferable than this.

Moreover, if it is the range which shows the effect of this invention, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 1, 4- cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, and a dimer further as an acid component in a polyester resin. Acid, 5-sodium sulfoisophthalic acid, 4-sodium sulfonaphthalene-2,7-dicarboxylic acid, adipic acid, azelaic acid, sebacic acid, etc. may be used. When copolymerizing these, it is preferable that an aromatic dicarboxylic acid component becomes 70 mol% or more, and also 80 mol% or more including naphthalenedicarboxylic acid from the point of moist-and-heat resistance and high refractive index. In particular, when attaching importance to heat-and-moisture resistance and high refractive index, the aromatic dicarboxylic acid component is preferably 90 mol% or more, more preferably 95 mol% or more, and particularly 100%.

If it is within the range showing the effect of the present invention, ethylene glycol, 1,3-propane glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diol as a diol component in the polyester resin You may use ethylene glycol, 1, 4- cyclohexane dimethanol, xylene glycol, the ethylene oxide adduct of bisphenol A, etc.

Moreover, when content of the polyurethane resin which has a polycarbonate frame|skeleton in an application layer is decreased, the flexibility of a coating film worsens, and there exists a possibility that scraping of an application layer and drop-off|omission of particle|grains by post-processing etc. may occur. In such a case, it is one of a preferable aspect to make polyester resin contain the dicarboxylic acid component represented by following formula (1), and/or the diol component represented by following formula (2).

(1) HOOC-(CH2)n-COOH (wherein n is an integer of 4≤n≤10)

(2) HO-(CH2)n-OH (wherein n is an integer of 4≤n≤10)

In this way, by containing an acid component and/or a diol component having a carbon component of a specific length, flexibility is imparted to the polyester resin, and even relatively large particles are easily maintained, thereby suppressing chipping of the coating layer and drop-off of particles. can do.

Adipic acid, sebacic acid, azelaic acid, etc. are mentioned as a dicarboxylic acid component of Formula (1). Moreover, as a diol component of Formula (2), a butanediol, hexanediol, etc. are mentioned.

The polyester resin is 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), or an organic solvent (for example, toluene, acetic acid (酢酸) ethyl, etc.) dissolved or dispersed may be used.

When a polyester resin is used as an aqueous coating liquid, a water-soluble or water-dispersible polyester resin is used. For such water-soluble or water oxidation, a compound containing a sulfonate group or a carboxylate group is included. It is preferable to copolymerize the compound.

It is preferable that the number average molecular weight of a polyester resin is 5000-40000 from points, such as coating-film intensity|strength and water dispersion easiness. More preferably, it is 10000-30000, Especially preferably, it is 12000-25000.

In addition, a single thing may be sufficient as the polyester resin containing a naphthalenedicarboxylic acid component, and 2 or more types of mixture may be sufficient as it. When it is a mixture of 2 or more types, it is preferable that it is the said composition as a sum total of polyester resin components.

As other components contained in the coating layer, a binder resin other than a polyurethane resin having a polycarbonate skeleton or a polyester resin containing a naphthalenedicarboxylic acid component, a crosslinking agent, lubricant particles, and the refractive index of the coating layer Although metal oxide particle|grains, surfactant, etc. are mentioned for height, in this invention, it is preferable that the metal oxide particle which raises the refractive index of a crosslinking agent, a lubricant particle, and an application layer is contained. The coating liquid contains a solvent and may contain a surfactant, etc., but the mass of the solvent remaining after drying and curing and the mass of the solid content of the surfactant are very trace amounts, and when calculating the composition of each component by calculation from the coating liquid, , The mass of the residual solvent or the mass of the solid content of the surfactant does not necessarily have to be included in the mass of the solid content of the entire coating layer, and the composition of the examples is based on the above calculation.

In order to form a crosslinked structure in an application layer, the crosslinking agent may be contained and formed in the application layer. By containing a crosslinking agent, it becomes possible to further improve the adhesiveness under high temperature, high humidity. Specific examples of the crosslinking agent include urea-based, epoxy-based, melamine-based, isocyanate-based, oxazoline-based, and carbodiimide-based crosslinking agents. Among these, the melamine type, isocyanate type, oxazoline type, and carbodiimide type crosslinking agents are preferable from the effect of improving the stability with time of a coating liquid and adhesiveness under high temperature and high humidity processing. Moreover, in order to accelerate|stimulate a crosslinking reaction, a catalyst etc. can be used suitably as needed.

When comprised by including a crosslinking agent in an application layer, as for content of the crosslinking agent, 5 mass % or more and 50 mass % or less are preferable among all solid components of an application layer. More preferably, they are 10 mass % or more and 40 mass % or less. If it is 10 mass % or more, the strength of the resin of the application layer is maintained, and the adhesion under high temperature and high humidity is good, and if it is 40 mass % or less, the flexibility of the resin of the application layer is maintained, and the adhesion is maintained at room temperature, high temperature, high humidity, and it is preferable. Do.

Moreover, it is preferable to make refractive index 1.7 or more contain the metal oxide particle (particle A) of high refractive index in an application layer. As such a metal oxide, TiO ₂ (refractive index 2.7), ZnO (refractive index 2.0), Sb ₂ O ₃ (refractive index 1.9), SnO ₂ (refractive index 2.1), ZrO ₂ (refractive index 2.4), Nb ₂ O ₅ (refractive index 2.3) ), CeO ₂ (refractive index 2.2), Ta ₂ O ₅ (refractive index 2.1), Y ₂ O ₃ (refractive index 1.8), La ₂ O ₃ (refractive index 1.9), In ₂ O ₃ (refractive index 2.0), Cr ₂ O ₃ ( refractive index 2.5) and the like, and composite oxide particles containing these metal atoms.

The lower limit of the refractive index of the particle A is preferably 1.7, more preferably 1.75. The upper limit of the refractive index of particle A becomes like this. Preferably it is 3.0, More preferably, it is 2.7, More preferably, it is 2.5. By making the above into a range, low coherence, transparency, adhesiveness, and blocking resistance can be balanced favorably.

The composite oxide particles used as the particles A _{are preferably TiO 2} /ZnO particles (zirconia/titania mixed particles). The zirconia/titania mixed particles are a group of particles containing both zirconia and titania in an aggregated state in which zirconia and titania are individually dispersed in a single liquid and do not form a composite. Of course, in the coating layer, the liquid component has almost evaporated and disappeared in the drying step or the curing step. When the coating layer contains such particle A, it is excellent in the balance of slipperiness|lubricacy and transparency, and high transparency and low coherence can be ensured. The liquid is preferably an aqueous liquid in order to facilitate the formation of the application layer by the so-called in-line coating method described later.

The zirconia/titania mixed particles may contain other components other than zirconia/titania, and may be inorganic particles or organic particles. Although not particularly limited, silica, titanium dioxide (titania), zirconium oxide (zirconia), talc , inorganic particles inactive to metal oxides such as kaolinite, and polyesters such as calcium carbonate, calcium phosphate, and barium sulfate are exemplified.

It is preferable that the average particle diameter of particle|grains A is 5 nm or more, More preferably, it is 10 nm or more, More preferably, it is 15 nm or more, Especially preferably, it is 20 nm or more. If the average particle diameter of particle A is 5 nm or more, it is difficult to aggregate, and it is preferable.

It is preferable that the average particle diameter of particle|grains A is 200 nm or less, More preferably, it is 150 nm or less, More preferably, it is 100 nm or less, Especially preferably, it is 60 nm or less. As for the average particle diameter of particle|grain A, transparency is favorable in it being 200 nm or less, and it is preferable.

In this invention, it is preferable to contain lubricant particle (particle B) in an application layer.

Particle B is (1) silica, kaolinite, talc, light calcium carbonate, ground calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, satin white, aluminum silicate, diatomaceous earth , calcium silicate, aluminum hydroxide, hydrous halloysite, magnesium carbonate, magnesium hydroxide, etc. inorganic particles, (2) acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene/acrylic, styrene/butadiene , polystyrene/acrylic, polystyrene/isoprene, polystyrene/isoprene, methyl methacrylate/butyl methacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol, diallyl phthalate, poly Although organic particle|grains, such as an ester type, are mentioned, In order to provide moderate slidability to an application layer, silica is used especially preferably.

It is preferable that the average particle diameter of particle|grains B is 200 nm or more, More preferably, it is 250 nm or more, More preferably, it is 300 nm or more, Especially preferably, it is 350 nm or more. If the average particle diameter of particle B is 200 nm or more, it is difficult to aggregate, and sliding property can be ensured, and it is preferable.

It is preferable that the average particle diameter of particle|grains B is 2000 nm or less, More preferably, it is 1500 nm or less, More preferably, it is 1000 nm or less, Especially preferably, it is 700 nm or less. Transparency is maintained as the average particle diameter of particle|grains B is 2000 nm or less, and particle|grains do not fall off, and it is preferable.

Particles A and B may be surface treated, and as the surface treatment method, there are physical surface treatment such as plasma discharge treatment or corona discharge treatment, and chemical surface treatment using a coupling agent, but use of a coupling agent is preferred. As the coupling agent, an organoalkoxy metal compound (eg, a titanium coupling agent or a silane coupling agent) is preferably used. When the particle B is silica, the silane coupling treatment is particularly effective. As a surface treatment agent for the particle B, it may be used in order to surface-treat previously before preparation of the said layer coating liquid, You may add it as an additive further at the time of this layer coating liquid preparation, and you may make it contain in the said layer. Of course, you may use it for particle A.

It is preferable that content of the particle|grains A in an application layer is 2 mass % or more, More preferably, it is 3 mass % or more, More preferably, it is 4 mass % or more, Especially preferably, it is 5 mass % or more. If content of the particle|grains A in an application layer is 2 mass % or more, the refractive index of an application layer can be kept high, low coherence is acquired effectively, and it is preferable.

It is preferable that content of the particle|grains A in an application layer is 50 mass % or less, More preferably, it is 40 mass % or less, More preferably, it is 30 mass % or less, Especially preferably, it is 20 mass % or less. If content of the particle|grains A in an application layer is 50 mass % or less, film-forming property is maintained and it is preferable.

It is preferable that content of the particle|grains B in an application layer is 0.01 mass % or more, More preferably, it is 0.05 mass % or more, More preferably, it is 0.1 mass % or more. When content of the particle|grains B in an application layer is 0.01 mass % or more, moderate slidability is maintained and it is preferable.

It is preferable that content of the particle|grains B in an application layer is 2 mass % or less, More preferably, it is 1.5 mass % or less, More preferably, it is 1 mass % or less. A haze is kept low that content of the particle|grains B in an application layer is 2 mass % or less, and it is preferable at a point of transparency.

It is preferable that the film thickness of an application layer is 0.001 micrometer or more, More preferably, it is 0.01 micrometer or more, More preferably, it is 0.02 micrometer or more, Especially preferably, it is 0.05 micrometer or more. If the film thickness of an application layer is 0.001 micrometer or more, adhesiveness is favorable and it is preferable.

It is preferable that the film thickness of an application layer is 2 micrometers or less, More preferably, it is 1 micrometer or less, More preferably, it is 0.8 micrometer or less, Especially preferably, it is 0.5 micrometer or less. If the film thickness of the application layer is 2 µm or less, there is no fear of causing blocking, which is preferable.

The coating layer can also contain surfactant for the purpose of improving the leveling properties at the time of application and defoaming the coating liquid. The surfactant may be any of cationic, anionic, nonionic, and the like, but a silicone-based, acetylene glycol-based, or fluorine-based surfactant is preferable. It is preferable to contain these surfactants in an application layer in the range which does not impair the suppression effect of an iris-like color under a fluorescent lamp, or adhesiveness.

In order to impart other functionalities to the coating layer, various additives may be contained within the range of not impairing the effect of suppressing the iris-like color under a fluorescent lamp or the adhesion. As said additive, a fluorescent dye, a fluorescent whitening agent, a plasticizer, a ultraviolet absorber, a pigment dispersing agent, a foam inhibitor, an antifoamer, an antiseptic|preservative etc. are mentioned, for example.

As a coating method, both the so-called in-line coating method, which is applied at the same time as the polyester base film is formed, and the so-called off-line coating method, which is applied with a separate coater after the polyester base film is formed, can be applied, but the in-line coating method is more efficient and more desirable.

As a coating method, a well-known arbitrary method can be used for the method for apply|coating a coating liquid to a polyethylene terephthalate (it abbreviates hereafter as PET) film. 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 and the like. These methods are applied individually or in combination.

In this invention, as a method of providing an application layer on a polyester film, the method of apply|coating and drying the coating liquid containing a solvent, particle|grains and resin to a polyester film is mentioned. Examples of the solvent include organic solvents such as toluene, water, or a mixed system of water and water-soluble organic solvents. Preferably, water alone or a water-soluble organic solvent mixed with water is preferable from the viewpoint of environmental problems. .

Although the solid content concentration of a coating liquid changes also with the kind of binder resin, the kind of solvent, etc., it is preferable that it is 2 mass % or more, and it is more preferable that it is 4 mass % or more. It is preferable that the solid content concentration of a coating liquid is 35 mass % or less, More preferably, it is 15 mass % or less.

The drying temperature after application also varies depending on the type of binder resin, the type of solvent, the presence or absence of a crosslinking agent, and the solid content concentration, but is preferably 80°C or higher, and preferably 250°C or lower.

The surface roughness (Ra) of the coating layer is related to the slipperiness of the surface of the coating layer, etc., and is preferably 0.01 nm or more, more preferably 0.1 nm or more, still more preferably 0.2 nm or more, particularly preferably 0.5 nm or more. On the other hand, about the upper limit of the surface roughness Ra of an application layer, it is preferable that it is 200 nm or less, More preferably, it is 100 nm or less, More preferably, it is 80 nm or less, Especially preferably, it is 50 nm or less.

(Manufacture of easily adhesive polyester film for optical use)

The easily adhesive polyester film for optics of this invention can be manufactured according to the manufacturing method of a general polyester film. For example, after the polyester resin is melted, extruded into a sheet, and the molded unoriented polyester is stretched in the longitudinal direction using the speed difference of the rolls at a temperature above the glass transition temperature, a tenter The method of extending|stretching in the transverse direction and performing heat processing is mentioned.

Although the polyester film of the present invention may be a uniaxially stretched film or a biaxially stretched film, when the biaxially stretched film is used as a protective film for the entire surface of the liquid crystal panel, rainbow-like color unevenness is not seen even when observed from directly above the film surface, When it observes from the diagonal direction, since rainbow-like color nonuniformity may be observed, caution is required.

This phenomenon is that the biaxially stretched film is composed of a refractive index ellipsoid having different refractive indices in the traveling direction, the width direction, and the thickness direction, and the in-plane retardation becomes zero due to the transmission direction of light inside the film (the refractive index ellipsoid is a perfect circle). visible) direction. Therefore, when the liquid crystal display screen is observed from a specific direction in the oblique direction, a point at which in-plane retardation becomes zero may occur, and rainbow-like color unevenness occurs concentrically around that point. If the angle from directly above the film plane (normal direction) to the position where the rainbow-like color unevenness is seen is θ, the angle θ increases as the birefringence in the film plane increases, and the rainbow-like color unevenness becomes difficult to see. In a biaxially stretched film, since the angle (theta) tends to become small, the direction of a uniaxial stretched film becomes difficult to see rainbow-like color unevenness, and is preferable.

However, in a perfectly uniaxial (uniaxially symmetric) film, since the mechanical strength of the direction orthogonal to an orientation direction falls remarkably, it is unpreferable. It is preferable that the present invention has biaxiality (biaxial objectivity) in a range that does not substantially generate rainbow-like color unevenness or does not generate rainbow-like color unevenness in the viewing angle range required for a liquid crystal display screen. Do.

(Laminated Polyester Film)

In the present invention, the laminated polyester film mainly used for optical applications is a hard coat layer made of an electron beam or ultraviolet curable acrylic resin or siloxane thermosetting resin or the like on the coating layer of the easily-adhesive polyester film of the present invention. obtained by installing

It is also a preferable aspect to provide a functional layer on the application layer of the easily adhesive polyester film of this invention. The functional layer is for the purpose of preventing see-through, suppressing glare, suppressing rainbow spots, suppressing scratches, etc., in addition to the above-mentioned hard coat layer, an anti-glare layer, an anti-glare layer, an anti-reflection layer, a low-reflection layer, and an anti-static layer. layer that has As a functional layer, in the said technical field, well-known various things can be used, The kind in particular is not restrict|limited. Hereinafter, each functional layer is demonstrated.

For example, a well-known hard-coat layer can be used for formation of a hard-coat layer, Although it is although it does not specifically limit, Superposition|polymerization and/or reaction by drying, heat, a chemical reaction, or irradiating any of electron beam, radiation, and an ultraviolet-ray. A resin compound to be used can be used. Examples of such curable resins include melamine-based, acrylic-based, silicone-based, and polyvinyl alcohol-based curable resins, but photocurable acrylic-based curable resins are preferable from the viewpoint of obtaining high surface hardness or optical design. As such an acrylic curable resin, a polyfunctional (meth)acrylate-based monomer or an acrylate-based oligomer may be used, and examples of the acrylate-based oligomer include polyester acrylate, epoxy acrylate, and urethane acrylate. , a polyether acrylate type, a polybutadiene acrylate type, a silicone acrylate type, etc. are mentioned. By mixing a reactive diluent, a photoinitiator, a sensitizer, etc. with these acrylic curable resin, the composition for coatings for forming the said optical function layer can be obtained.

Said hard-coat layer may have the glare-proof function (anti-glare function) which scatters external light. The anti-glare function (anti-glare function) is obtained by forming irregularities on the surface of the hard coat layer. At this time, it is preferable that the haze of a film is 0 to 50 % ideally, More preferably, it is 0 to 40 %, Especially preferably, it is 0 to 30 %. Of course, 0 % is an ideal thing, and 0.2 % or more may be sufficient, and 0.5 % or more may be sufficient.

Therefore, the use of the film of the present invention is mainly for the overall optical film, LCD such as prism lens sheet, AR (anti-reflection) film, hard coat film, diffuser plate, anti-shattering film, flat TV, CRT, etc. It can be used suitably for transparent conductive films, such as a base film of the member for optics, a near-infrared absorption filter which is a member for the front plate for plasma displays, a touch panel, and electroluminescence.

As an acrylic resin hardening|cured by the electron beam or ultraviolet-ray for the above-mentioned hard-coat layer formation, it has an acrylate-type functional group, For example, comparatively low molecular-weight polyester resin, polyether resin, acrylic resin. , epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, oligomers or prepolymers such as (meth)acrylates of polyfunctional compounds such as polyhydric alcohols, and ethyl (meth) as a reactive diluent Monofunctional monomers such as acrylate, ethylhexyl (meth) acrylate, styrene, methyl styrene, and N-vinyl pyrrolidone, 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 What contains (meth)acrylate, neopentyl glycol di(meth)acrylate, etc. can be used.

However, in the case of an electron beam or ultraviolet curable resin, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethylthiuram monosulfide, thioxanthone as a photopolymerization initiator in the above resins As a solvent or a photosensitizer, n-butylamine, triethylamine, tri-n-butylphosphine, etc. can be mixed and used.

In addition, the silicone-based (siloxane-based) thermosetting resin can be produced by hydrolysis and condensation reaction of an organosilane compound alone or in a mixture of two or more under an acid or base catalyst. In particular, in the case of low-reflection use, it is better to mix at least one fluorosilane compound to perform hydrolysis and condensation reaction in order to improve low refractive index, stain resistance, and the like.

(Production of laminated polyester film)

Although the manufacturing method of the laminated polyester film in this invention is demonstrated taking an easily adhesive polyester film as an example, of course, it is not limited to this.

The above-mentioned electron beam or ultraviolet curable acrylic resin or siloxane-based thermosetting resin is applied to the surface of the coating layer of the easily-adhesive polyester film. When an application layer is provided on both surfaces, it apply|coats to at least one application layer surface. The coating liquid does not need to be diluted in particular, but there is no problem in particular even if it is diluted with an organic solvent according to the needs of the coating liquid, such as viscosity, wettability, and coating film thickness. The coating layer forms a hard coat layer by applying the coating liquid to the above-mentioned film, drying the coating liquid as necessary, and curing the coating layer by irradiation with electron beams or ultraviolet rays and heating according to the curing conditions of the coating liquid.

In this invention, it is preferable that the thickness of a hard-coat layer is 1-15 micrometers. The effect with respect to the chemical-resistance as a hard-coat layer, abrasion resistance, and antifouling property as the thickness of a hard-coat layer being 1 micrometer or more is exhibited efficiently, and it is preferable. On the other hand, if the thickness is 15 µm or less, the flexibility of the hard coat layer is maintained and there is no fear of cracking or the like, which is preferable.

As for the scratch resistance, when the coated surface is abraded with black paper, it is preferable that the scratch is not conspicuous with the naked eye. When a flaw is conspicuous in said evaluation, it is difficult to damage|wound at the time of a guide roll passing, and it is preferable from a viewpoint of handling property, etc.

The lower limit of the coefficient of static friction (μs) is preferably 0.3, and if it is 0.3 or more, there is no problem of excessive slipping, so it becomes easy to roll up with a roll of hard chrome plating in the manufacturing process, and handling and blocking resistance are maintained. It is preferable to be The upper limit of the coefficient of static friction (µs) is preferably 0.5, and if it is 0.5 or less, there is no fear of scratching the film serving as the contact surface at the time of winding up, which is preferable.

The lower limit of the coefficient of kinetic friction (μd) is preferably 0.4, and if it is 0.4 or more, there is no problem of excessive slipping, so it is easy to roll up with a roll of hard chrome plating in the manufacturing process, and handling and blocking resistance are maintained. It is preferable to be The upper limit of the coefficient of kinetic friction (µd) is preferably 0.6, and if it is 0.6 or less, there is no fear of scratching the film serving as the contact surface at the time of winding up, which is preferable.

Since the polyester film of this invention is mainly used as an easily adhesive film for optics, it is preferable to have high transparency. The lower limit of the haze is 0% ideally, and the closer to 0%, the more preferable. The upper limit of the haze is preferably 2%, and if it is 2% or less, the light transmittance is good, and a clear image can be obtained in a liquid crystal display device, which is preferable. The haze of a polyester film can be measured according to the method mentioned later, for example.

As for the adhesiveness of an easily adhesive layer property application layer and a hard-coat layer, by evaluation by the measuring method mentioned later, Preferably, it is preferable that a minimum is 80 %, Preferably, an upper limit is 100 %. If it is 80 % or more, it can be said that the adhesiveness of an application layer and a hard-coat layer was fully maintained.

About the adhesiveness under high-temperature, high-humidity conditions of the easily adhesive layer and hard-coat layer evaluated according to the method mentioned later, Preferably, it is preferable that the lower limit is 10%, The upper limit of high-temperature, high-humidity adhesiveness becomes like this. Preferably it is 100%. When it is 10 % or more, the adhesiveness of an easily bonding layer and a hard-coat layer is somewhat satisfied on high temperature, high humidity conditions, and the passability in a post-processing process is satisfy|filled somewhat. More preferably, it is 50 % or more.

It is preferable that the polyester film for polarizer protection provided with the hard coat cannot confirm the interference unevenness by the evaluation method mentioned later, and if the interference unevenness by the said evaluation method cannot be confirmed, the visibility of a liquid crystal image device becomes favorable, and it is preferable Do.

Although the easily adhesive polyester film of this invention can be used for various uses, it is preferably used in the manufacturing process of the polarizing plate used for a liquid crystal display device, It is used especially preferably as a protective film of the polarizer which comprises a polarizing plate . Usually, the polarizer is made from polyvinyl alcohol in many cases, and the easily adhesive polyester film of this invention is adhere|attached using the polyvinyl alcohol agent, the adhesive agent which added the crosslinking agent, etc. to the polarizer as needed. In that case, it is more preferable to use the application layer of the easily adhesive polyester film of this invention toward the opposite surface instead of the surface on the side to adhere|attach with a polarizer. On the surface to be adhered to the polarizer of the easily-adhesive polyester film of the present invention, for example, as described in International Publication No. 2012/105607, a polyester-based resin, a polyvinyl alcohol-based resin, and a crosslinking agent It is preferable that the adhesive layer is laminated|stacked.

Example

Next, although this invention is demonstrated in detail using an Example, a comparative example, and a reference example, this invention is not limited to a following example of course. In addition, the evaluation method used by this invention is as follows.

(1) Average particle size

[Measurement method by scanning electron microscope]

The measurement of the average particle diameter of said particle|grains can be performed by the following method. The particles are photographed with a scanning electron microscope (SEM), and the maximum diameter (distance between the two most distant points) of 300 to 500 particles is measured at a magnification such that the size of one smallest particle is 2 to 5 mm. , the average value is taken as the average particle diameter. The average particle diameter of the particle|grains which exist in the application layer in this invention can be measured with the said measuring method.

[Dynamic light scattering method]

The average particle diameter of particle|grains can also be calculated|required by the dynamic scattering method at the time of manufacture of particle|grains or a film. The sol was diluted with a dispersion medium, measured with a submicron particle analyzer N4 PLUS (manufactured by Beckman Coulter) using the parameters of the dispersion medium, and calculated by the cumulant method to obtain an average particle diameter. By the dynamic light scattering method, the average particle diameter of the particle|grains in a sol is observed, and when there exists aggregation of particle|grains, the average particle diameter of these flock|aggregates is observed.

(2) the refractive index of the particle

The refractive index of particles can be measured by the following method. After drying the inorganic particles at 150°C, the powder pulverized with a mortar is immersed in solvent 1 (those having a lower refractive index than the particles), and then solvent 2 (those having a higher refractive index than the particles) is added little by little to make the fine particles almost transparent. added until The refractive index of this liquid was measured using the Abbe refractometer (Abbe refractometer manufactured by Atago Corporation). The measurement was performed at 23°C and D-line (wavelength 589 nm). The solvent 1 and the solvent 2 are selected to be miscible with each other, and depending on the refractive index, for example, 1,1,1,3,3,3-hexafluoro-2-propanol, 2-propanol, chloroform, carbon tetrachloride, toluene and solvents such as glycerin.

(3) Haze of easily adhesive polyester film

The haze of the easily adhesive polyester film was measured using the turbidimeter (the Nippon Denshoku make, NDH2000) based on JISK7136:2000.

(4) Adhesion

On the easily adhesive layer of the polyester film obtained in the Example, the hard-coat layer described in the item of formation of the above-mentioned hard-coat layer was formed. The adhesiveness of a hard-coat layer and a base film is calculated|required based on the base material of 8.5.1 of JIS-K5400-1990 for the polyester film for easily bonding in which the hard coat was formed.

Specifically, using a cutter guide having a gap of 2 mm, 100 checkerboard cuts reaching the base film through the hard coat layer are pasted on the hard coat layer surface. Next, a cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm wide) is attached to the checkerboard cut surface, and rubbed with an eraser to completely adhere. Thereafter, the cellophane adhesive tape is vertically peeled from the hard coat layer surface of the hard coat laminated polarizer protective film, and the number of checkers peeled off from the hard coat layer surface of the hard coat laminated polarizer protective film is visually counted, and the hard coat layer and Adhesiveness with a base film is calculated|required. In addition, those partially peeled off among the boards are counted as the peeled boards.

Adhesion (%) = {1-(Number of stripped boards/100)}×100

(5) Interference fringe improvement (iris-like color)

The hard-coat layer was formed on the easily adhesive layer of the easily adhesive polyester film for optics obtained in each Example. The easily adhesive polyester film for optics in which the hard coat was formed was cut out in the area of 10 cm (film width direction) x 15 cm (film longitudinal direction), and the sample film was created. On the surface opposite to the hard-coat layer surface of the obtained sample film, the black glossy tape (The Nitto Denko Co., Ltd. make, vinyl tape No21; black) was stuck. With the hard coat surface of this sample film as the upper surface, and a three-wavelength main white (National Farouk, FL 15EX-N 15W) as the light source, the positional relationship (distance from the light source) where reflection is most visible from the diagonal line. 40 to 60 cm, an angle of 15 to 45 degrees).

The results observed with the naked eye are ranked according to the following criteria. In addition, observation is performed by 5 people familiar with the said evaluation, and let the most rank be an evaluation rank. For example, when two ranks were equal in number, the center of the rank divided into three was employed. For example, if ◎ and ○ are 2 people each and △ is 1 person, then ○ if ◎ is 1 person and ○ and △ are 2 people each, then ○ and ◎ and △ are 2 people each and ○ is 1 person. In this case, ○ is adopted, respectively.

(double-circle): The iris-like color is not seen also in observation from all angles.

○: A slight iris-like color is seen depending on a certain angle.

△: Slightly iris-like color is observed.

×: A clear iris-like color is observed

(6) Blocking resistance

It overlapped so that the coated surfaces of the laminated|multilayer film of 2 sheets might oppose, a load of 5 kg/cm<2> was applied, and this was left to stand in 50 degreeC atmosphere for 24 hours. The superimposed film was peeled off, and the peeling state was judged by the following reference|standard.

(double-circle): can peel lightly

○: There is resistance at the time of peeling, but the application layer does not transfer to the mating surface

(triangle|delta): A peeling sound generate|occur|produced, and the coating layer is partially transferred to the mating surface

x: The film of 2 sheets adheres and cannot peel, or even if it can peel, the base film is split and cracked.

(7) glass transition temperature

According to JIS K7121-1987, using a differential scanning calorimeter (manufactured by Seiko Instruments, DSC6200), 10 mg of a resin sample was heated at 20°C/min over a temperature range of 25 to 300°C, obtained from the DSC curve The extrapolated glass transition initiation temperature was defined as the glass transition temperature.

(8) number average molecular weight

0.03 g of resin was dissolved in 10 ml of tetrahydrofuran, and using a GPC-LALLS device low-angle light scattering photometer LS-8000 (manufactured by Tosoh Corporation, tetrahydrofuran solvent, reference: polystyrene), column temperature 30° C., flow rate 1 ml/ The number average molecular weight was measured using a minute and a column (shodex KF-802, 804, 806 manufactured by Showa Denko Corporation).

(9) Resin composition

Resin was dissolved in heavy chloroform, and 1H-NMR analysis was performed using a nuclear magnetic resonance spectrometer (NMR) Gemini-200 manufactured by Varian Corporation, and the mole % ratio of each composition was determined from the integral ratio.

(Polymerization of polyester resin)

Polymerization of copolymerized polyester resins for coating layer (B1) to (B3)

342.0 parts by mass of dimethyl 2,6-naphthalenedicarboxylate, 35.0 parts by mass of dimethyl terephthalate, and 35.5 parts by mass of dimethyl-5-sodium sulfoisophthalate in a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux cooler. , 198.6 parts by mass of ethylene glycol, 118.2 parts by mass of 1,6-hexanediol, and 0.4 parts by mass of tetra-n-butyl titanate were put, and transesterification was carried out from 160°C to 220°C over 4 hours. Furthermore, 60.7 mass parts of sebacic acid was added, and the esterification reaction was performed. Subsequently, the temperature was raised to 255°C and the reaction system was gradually reduced in pressure, and then reacted under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolymerized polyester resin (B1). The obtained co-polyester resin was pale yellow and transparent.

The composition of the co-polyester resin (B1) is shown in Table 1.

Moreover, the raw material was changed and it carried out similarly, and obtained the co-polyester resin (B2) and (B3) of the composition shown in Table 1.

[Table 1]

(Preparation of polyester water dispersion)

30 parts by mass of co-polyester resin (B1) and 15 parts by mass of ethylene glycol-n-butyl ether were put into a reactor equipped with a stirrer, a thermometer and a reflux device, and the resin was dissolved by heating and stirring at 110°C. After the resin was completely dissolved, 55 parts by mass of water was gradually added to the polyester solution while stirring. After addition, it cooled to room temperature, stirring a liquid, and the milky white polyester water dispersion (Bw1) of 25 mass % of solid content was produced.

Similarly, an aqueous polyester dispersion Bw2 was obtained from the copolymerized polyester resin B2, and an aqueous polyester dispersion Bw3 was obtained from the copolymerized polyester resin B3.

(Production of polyurethane water dispersion)

Polymerization of water-soluble polyurethane resin (A1) containing aliphatic polycarbonate polyol as a component

In a four-neck flask equipped with a stirrer, a load cooler, a nitrogen inlet tube, a silica gel drying tube and a thermometer, 43.75 parts by mass of 4,4-diphenylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, and a poly having a number average molecular weight of 2000 153.41 parts by mass of hexamethylene carbonate diol, 0.03 parts by mass of dibutyl tin dilaurate, and 84.00 parts by mass of acetone as a solvent were added, and stirred for 3 hours at 75° C. in a nitrogen atmosphere, so that the reaction solution reached a predetermined amine equivalent confirmed that Next, after incubating this reaction liquid to 40 degreeC, 8.77 mass parts of triethylamines were added, and the polyurethane prepolymer solution was obtained. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25° C. ^{, stirred and mixed at 2000 min −1} , and a polyurethane prepolymer solution was added and dispersed in water. Then, the water-soluble polyurethane resin (A1) of 37 mass % of solid content was prepared by removing a part of acetone and water under reduced pressure. The glass transition point temperature of the obtained polyurethane resin was -30 degreeC.

Polymerization of water-soluble polyurethane resin (A2) containing aliphatic polycarbonate polyol as a component

38.41 parts by mass of isophorone diisocyanate, 6.95 parts by mass of dimethylolpropanoic acid, 158.99 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent. It carried out similarly to the superposition|polymerization of A1, and prepared the water-soluble polyurethane resin (A2).

(Polymerization of block polyisocyanate-based crosslinking agent)

100 parts by mass of a polyisocyanate compound having an isocyanurate structure using hexamethylene diisocyanate as a raw material (Duranate TPA, manufactured by Asahi Kasei Chemicals) in a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, propylene glycol monomethyl ether 55 mass parts of acetate and 30 mass parts of polyethyleneglycol monomethyl ether (average molecular weight 750) were put, and it hold|maintained at 70 degreeC in nitrogen atmosphere for 4 hours. Then, the reaction liquid temperature was lowered|hung to 50 degreeC, and 47 mass parts of methyl ethyl ketoxime was dripped. The infrared spectrum of the reaction liquid was measured, it confirmed that absorption of an isocyanate group had lose|disappeared, and obtained the blocked polyisocyanate aqueous dispersion (Cx1) of 40 mass % of solid content.

(Polymerization of oxazoline-based crosslinking agent)

A mixture of 58 parts by mass of ion-exchanged water as an aqueous medium and 58 parts by mass of isopropanol, and a polymerization initiator (2,2'-azobis(2) -Amidinopropane) and dihydrochloride) 4 mass parts were thrown in. On the other hand, 16 parts by mass of 2-isopropenyl-2-oxazoline as a polymerizable unsaturated monomer having an oxazoline group, methoxypolyethylene glycol acrylate (average added moles of ethylene glycol, 9 moles, Shin-Nakamura Chemical), to the dropping funnel Manufacture) 32 mass parts and the mixture of 32 mass parts of methyl methacrylates were thrown in, and it was dripped over 1 hour in 70 degreeC in nitrogen atmosphere. After completion of the dropwise addition, the reaction solution was stirred for 9 hours and cooled to obtain a water-soluble resin (Cx2) having an oxazoline group having a solid content concentration of 40% by mass.

(Polymerization of carbodiimide-based crosslinking agent)

Put 168 parts by mass of hexamethylene diisocyanate and 220 parts by mass of polyethylene glycol monomethyl ether (M400, average molecular weight 400) in a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, stirred at 120 ° C. for 1 hour, and further 4, 26 parts by mass of 4'-dicyclohexylmethane diisocyanate and 3.8 parts by mass of 3-methyl-1-phenyl-2-phosphoene-1-oxide (2% by mass relative to all isocyanate) as a carbodiimidization catalyst were added. and stirred at 185°C under a nitrogen stream for additional 5 hours. The infrared spectrum of the reaction solution was measured, and it was confirmed that absorption at a ^{wavelength of 2200 to 2300 cm -1 was lost.} It stood to cool to 60 degreeC, 567 mass parts of ion-exchange water was added, and the carbodiimide water-soluble resin (Cx3) of 40 mass % of solid content was obtained.

(epoxy crosslinking agent)

As the epoxy crosslinking agent, Denacol (registered trademark) EX-521 (solid content concentration: 100%) manufactured by Nagase Chemtex Co., Ltd. was used (epoxy crosslinking agent (Cx4)).

(Melamine-based crosslinking agent)

As the melamine-based crosslinking agent, becamine (registered trademark) M-3 (solid content concentration: 60%) manufactured by DIC Corporation was used (melamine-based crosslinking agent (Cx5)).

(zirconia particles)

With reference to Example 8 of Unexamined-Japanese-Patent No. 2008-290896, it carried out as follows.

In a 3-liter glass container, 2283.6 g of pure water and 403.4 g of oxalic acid dihydrate were put, and it heated at 40 degreeC, and the 10.72 mass % oxalic acid aqueous solution was prepared. While stirring this aqueous solution, 495.8 g of zirconium oxycarbonate powder (ZrOCO ₃ , manufactured by AMR International Corp. _{, containing 39.76 mass% in terms of ZrO 2} ) was gradually added and mixed for 30 minutes, followed by mixing at 90° C. for 30 minutes. heating was performed. Then, 1747.2 g of 25.0 mass % tetramethylammonium hydroxide aqueous solution (made by Tama Chemical Industry Co., Ltd.) was gradually added over 1 hour. At this point the mixture is a slurry, comprised 4.0% by mass in terms of ZrO _2. This slurry was transferred to a stainless steel autoclave container, and hydrothermal treatment was performed at 145°C for 5 hours. The product after this hydrothermal treatment had no unpeptide and was completely solised. The obtained sol, containing 4.0% by mass as ZrO _2, and the mean particle size due to pH 6.8, a dynamic light scattering method was 19nm. In addition, a transmittance measurement was adjusted with pure water to a sol by ZrO ₂ concentration of 2.0% by mass was 88%. When the particles were observed with a transmission electron microscope, most of them were aggregated particles _{of ZrO 2 primary particles having a diameter of around 7 nm. 4000 g of zirconia sol having a ZrO 2} concentration of 4.0 mass% obtained by performing the hydrothermal treatment described above was washed and concentrated while gradually adding pure water using an ultrafiltration device, and ZrO ₂ concentration of 13.1% by mass, pH 4.9, ZrO ₂ concentration of 13.1 953 g of zirconia sol having a transmittance of 76% in mass% was obtained.

_{To 300 g of a zirconia sol having a ZrO 2} concentration of 13.1% by mass obtained by performing the above washing and concentration, 3.93g of a 20% by mass aqueous solution of citric acid and 11.0g of a 25% by weight aqueous solution of tetramethylammonium hydroxide were added, and then concentrated with an ultrafiltration device. As a result, 129 g of high-concentration zirconia sol (Cpz1) having a _{ZrO 2 concentration of 30.5 mass% was obtained.} The obtained high-concentration zirconia sol had a pH of 9.3 and an average particle diameter of 19 nm by a dynamic light scattering method. Moreover, this zirconia sol had no sediment and was stable for 1 month or more under the conditions of 50 degreeC.

Furthermore, with reference to Example 2 of Unexamined-Japanese-Patent No. 2008-290896, Cpz2 with an average particle diameter of 32 nm, and Cpz3 with an average particle diameter of 48 nm with reference to Example 1 were obtained.

(titania particles)

With reference to Example 1 of Unexamined-Japanese-Patent No. 2011-132484, it carried out as follows.

12.09 kg of titanium tetrachloride aqueous solution containing 7.75 mass % of titanium tetrachloride (manufactured by Osaka Titanium Technologies Co., Ltd.) in _{terms of TiO 2} , and 4.69 kg of aqueous ammonia containing 15 mass % of ammonia (manufactured by Ubekosan Co., Ltd.) were mixed. , a white slurry liquid having a pH of 9.5 was prepared. Next, this slurry was filtered and washed with pure water to obtain 9.87 kg of an aqueous titanic acid cake having a solid content of 10 mass%. Next, 11.28 kg of hydrogen peroxide solution (manufactured by Mitsubishi Gas Chemical Co., Ltd.) containing 35 mass% of hydrogen peroxide and 20.00 kg of pure water were added to this cake, and then heated at a temperature of 80 ° C. for 1 hour with stirring, by adding pure water 57.52kg it was added to obtain a titanic acid peroxide aqueous solution containing 1 mass% of the peroxide titanate in terms of TiO ₂ based on 98.67kg. This aqueous titanic acid solution was transparent yellowish brown and had a pH of 8.5.

Next, 4.70 kg of a cation exchange resin (manufactured by Mitsubishi Chemical Co., Ltd.) was mixed with 98.67 kg of the aqueous titanic acid peroxide solution, and potassium tartrate (manufactured by Showa Kako Co., Ltd.) was contained in an amount of 1 mass% based on _{SnO 2 conversion.} 12.33 kg of potassium stannate aqueous solution was slowly added under stirring. Next, after isolate|separating the cation exchange resin into which potassium ion etc. were put, it put in the autoclave (Diatsu Glass Kogyo Co., Ltd. product, 120L), and it heated at the temperature of 165 degreeC for 18 hours.

Next, after cooling the obtained mixed aqueous solution to room temperature, it is concentrated with an ultrafiltration membrane device (manufactured by Asahi Kasei Co., Ltd., ACV-3010), and titanium-based fine particles having a solid content of 10% by mass (hereinafter referred to as “P-1”) ') containing 9.90 kg of an aqueous dispersion sol (Cpt1) was obtained. The solid matter contained in the thus-obtained sol was measured by the above method, and as a result, it was a titanium-based fine particle (primary particle) having a rutile-type crystal structure and composed of a complex oxide containing titanium and tin. In addition, when the content of the metal component contained in the titanium-based fine particles was measured, TiO ₂ 87.2 mass%, SnO ₂ 11.0 mass%, and K ₂ O 1.8 mass% on the basis of oxide conversion of each metal component. Moreover, the pH of this mixed aqueous solution was 10.0. In addition, the aqueous dispersion sol containing the titanium-based fine particles is transparent milky white, the average particle diameter of the titanium-based fine particles contained in the aqueous dispersion sol by dynamic light scattering method is 35 nm, and further coarse having a particle diameter of 100 nm or more The distribution frequency of (粗大) particles was 0%. In addition, the refractive index of the obtained titanium-based microparticles|fine-particles could be regarded as 2.42.

Furthermore, with reference to Example 2 of Unexamined-Japanese-Patent No. 2011-132484, Cpt2 with an average particle diameter of 32 nm, and Cpt3 with an average particle diameter of 42 nm with reference to Example 4 were obtained.

(Zirconia/Titania mixed particles)

By mixing the obtained zirconia particles (Cpz1) and titania particles (Cpt1) at a mass ratio of 75/25, zirconia/titania mixed particles ((Cp1): average particle diameter of 23 nm) having a solid content concentration of 13 mass% were prepared.

In the same manner, Cp2 (average particle diameter of 32 nm) was obtained from Cpz2 and Cpt2, and Cp3 (average particle diameter of 46 nm) was obtained from Cpz3 and Cpt3.

(ceria particles)

With reference to Japanese Patent Laid-Open No. 2011-132107, an experiment was conducted as follows.

216 g of cerium(III) chloride heptahydrate was placed in 10 L of distilled water, stirred and dissolved. Moreover, the temperature was raised to 93 degreeC, continuing stirring, and the whole quantity of 5.6 kg of 1.0% sodium hydroxide aqueous solution was added at once. Furthermore, after stirring at 93 degreeC for 6 hours, it cooled to 25 degreeC, and obtained white precipitate.

The precipitate was separated by a centrifuge, and 15 L of distilled water was added to the resulting precipitate, stirred and redispersed, and the precipitate was separated by a centrifuge. This operation was performed 3 times in total, and the deposit was wash|cleaned.

Distilled water was added to the obtained precipitate, the pH was adjusted to 9.2, and it was dispersed with an ultrasonic disperser to obtain a ceria particle dispersion (Cp4) having a solid content concentration of 12% by mass. The average particle diameter by the dynamic light scattering method was 34 nm.

(Formation of hard coat layer)

On the side opposite to the side to be adhered to the polarizer of the polyester film prepared in Examples to be described later, the coating liquid for forming a hard coat layer of the following composition is applied using a #10 wire bar, and dried at 70° C. for 1 minute. , the solvent was removed. Next, the film to which the hard coat layer was applied ^{was irradiated with ultraviolet light of 300 mJ/cm 2} using a high-pressure mercury lamp to obtain a polarizer protective film having a hard coat layer having a thickness of 5 µm.

・Coating liquid for forming a hard coat layer

methyl ethyl ketone 65.00 mass%

Dipentaerythritol hexaacrylate 27.20% by mass

(A-DPH manufactured by Shin-Nakamura Chemical)

polyethylene diacrylate 6.80 mass%

(A-400 manufactured by Shin-Nakamura Chemical)

photopolymerization initiator 1.00 mass%

(Irgacure 184 manufactured by Chiba Specialty Chemicals)

(Example 1)

coating liquid raw material

Particle A water dispersion: zirconia/titania mixed particles (Cp1) with an average particle diameter of 23 nm

(75 mass % of zirconia amount in zirconia/titania, 13 mass % of solid content concentration)

- Particle B aqueous dispersion: silica sol with an average particle diameter of 450 nm (solid content concentration: 4 mass%)

・Polyester water dispersion ((Bw1), solid content concentration of 25% by mass)

・Polyurethane water dispersion ((A1), solid content concentration 37% by mass)

-Block isocyanate type crosslinking agent ((Cx1), solid content concentration 40 mass %)

(1) Adjustment of coating solution for easily adhesive layer

The coating liquid of the following composition was adjusted.

water 36.00 parts by mass

isopropyl alcohol 30.31 parts by mass

Particle A water dispersion 10.99 parts by mass

Particle B water dispersion 0.91 parts by mass

polyester water dispersion 8.80 parts by mass

polyurethane water dispersion 3.96 parts by mass

Block isocyanate type crosslinking agent 5.50 parts by mass

high boiling point solvent (NMP) 3.00 parts by mass

Surfactant (fluorine-based, solid content concentration 10% by mass) 0.25 parts by mass

(2) Preparation of easily adhesive polyester film

As a film raw material polymer, PET resin pellets having an intrinsic viscosity (solvent: phenol/tetrachloroethane = 60/40) of 0.62 dl/g and containing substantially no particles were prepared at 6 at 135°C under a reduced pressure of 133 Pa. time to dry. Thereafter, it was supplied to an extruder, melt-extruded into a sheet at about 280°C, and solidified by rapid cooling on a rotating cooling metal roll maintained at a surface temperature of 20°C to obtain an unstretched PET sheet.

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

Next, after apply|coating the said coating liquid to the single side|surface of a PET film by the roll coating method, it dried at 80 degreeC for 15 second. Moreover, it adjusted so that the application amount after drying after final extending|stretching ^{might be set to 0.12 g/m<2>.} Subsequently, with a tenter, the film was stretched 4.0 times in the width direction at 150° C., in a state in which the length of the film in the width direction was fixed, heated at 230° C. for 0.5 second, and further relaxed at 230° C. for 10 seconds 3% in the width direction. was carried out to obtain an optically easily-adhesive polyester film having a thickness of 38 µm. The polyurethane resin component, the polyester resin component, and other components in an application layer are 20 mass %, 30 mass %, and 50 mass %, respectively, as Table 2 described.

(Examples 2, 3, 18-25, Comparative Examples 1-7)

An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the ratio of the polyurethane resin component, the polyester resin component, and other components in the coating layer was set to Table 2 or 3.

(Examples 4-7)

An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the crosslinking agent of the coating liquid was changed and the composition of each component in the coating layer was changed as described in Table 2.

(Examples 8 to 12)

The easily-adhesive polyester film was obtained like Example 1 except having changed the kind of particle|grains A of the coating liquid and having changed the composition of each component in an application layer according to Table 2.

(Examples 13 to 15)

Except having changed the film thickness of the application layer according to Table 2, it carried out similarly to Example 1, and obtained the easily adhesive polyester film.

(Examples 16 and 17)

An easily adhesive polyester film was obtained like Example 1 except having changed the quantity of the particle|grain B in an application layer according to Table 2.

(Examples 26 and 27)

An easily-adhesive polyester film was obtained like Example 1 except having changed the kind of co-polyester resin component according to Table 3.

(Example 28)

Except having changed the kind of polyurethane resin component according to Table 3, it carried out similarly to Example 1, and obtained the easily adhesive polyester film.

Each result is shown in Tables 2 and 3. Moreover, the plot on the triangular diagram of each Example and a comparative example is shown on FIG.

[Table 2]

[Table 3]

(Coefficient of static friction, coefficient of kinetic friction (㎲, μd))

In addition, the friction coefficient of the polyester film obtained in Examples and Comparative Examples was measured using a Tenshiron (Toyo Baldwin, RTM-100) in accordance with JIS K7125-1999 Plastic-Film and Sheet Friction Coefficient Test Method. The film also had a static friction coefficient (µs) of 0.35 to 0.5 and a kinetic friction coefficient (µd) in the range of 0.45 to 0.6, and there was no problem in winding-up properties and handling properties.

Industrial Applicability

According to the present invention, it is excellent in low coherence, transparency, blocking resistance, adhesion with various functional layers, and sliding properties that can suppress rainbow spots, and can be used suitably in optical applications, particularly polarizer protective film applications. It became possible to provide an adhesive polyester film and a laminated polyester film using the above.

P1: a straight line passing through the coordinates (10, 55, 35) and (10, 10, 80)
Q1: A straight line passing through the coordinates (10, 10, 80) and (70, 10, 20)
R1: a straight line passing through the coordinates (70, 10, 20) and (50, 40, 10)
S1: a straight line passing through the coordinates (45, 45, 10) and (10, 55, 35)
○: Plot of each example
□: Plot of each comparative example
Numerical values in the triangular diagram: the number of each example or each comparative example

Claims (4)

On at least one side of the polyester film, a polyurethane resin having a polycarbonate skeleton, and an application layer containing a polyester resin having a naphthalene skeleton, on the application layer, a hard coat layer, an anti-glare layer, an anti-glare anti-reflection layer, A laminated polyester film having at least one functional layer selected from the group consisting of an antireflection layer and a low reflection layer, wherein the content (mass%) of the polyurethane resin component when the total solid content of the coating layer is 100% by mass is a, naphthalene When the content (mass %) of the polyester resin component having a skeleton is b, and the total amount (mass %) of the components other than these is represented in the triangular diagram as c, a, b, and c are straight lines P1, straight lines Q1, straight lines Laminated polyester film in the area surrounded by four straight lines of R1, straight line S1:
Here, the straight line P1, the straight line Q1, the straight line R1, and the straight line S1 are as follows;
Straight line P1: a straight line passing through a point where a is 10 mass%, b is 55 mass%, and c is 35 mass%, and a is 10 mass%, b is 10 mass%, and c is 80 mass%
Straight line Q1: a straight line passing through a point where a is 10 mass%, b is 10 mass%, and c is 80 mass%, and a is 70 mass%, b is 10 mass%, and c is 20 mass%
Straight line R1: a straight line passing through a point where a is 70 mass%, b is 10 mass%, and c is 20 mass%, and a is 50 mass%, b is 40 mass%, and c is 10 mass%
Straight line S1: A straight line passing through the point where a is 45 mass%, b is 45 mass%, and c is 10 mass%, and the point where a is 10 mass%, b is 55 mass%, and c is 35 mass%. The method of claim 1,
The laminated polyester film in which an application layer contains a crosslinking agent. 3. The method according to claim 1 or 2,
The laminated polyester film in which an application layer contains the metal oxide particle (particle A) of refractive index 1.7 or more. 3. The method according to claim 1 or 2,
The laminated polyester film in which an application layer contains lubricant particle (particle B).

Images