KR20200027542A - Easy-adhesive polyester film - Google Patents

Abstract

[PROBLEMS] The present invention is excellent in both low coherence to suppress rainbow stains, adhesion to a hard coat layer required for a high level in various optical applications, blocking resistance, transparency, and further, high slipping property. It is to provide a self-adhesive polyester film which can be suitably used in an optical application having excellent handling properties in a manufacturing process or in a post process such as a manufacturing process of a polarizing plate of a liquid crystal display device.
[Solutions] The present invention has a coating layer containing a polyurethane resin having a polycarbonate skeleton and a polyester resin having a naphthalene skeleton on at least one side of the polyester film, and the total amount of solid content of the coating layer is 100% by mass. When the content a of the polyurethane resin component a, 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 defined by four specific straight lines. A self-adhesive polyester film in an enclosed area is provided.

Description

Easy-adhesive polyester film

The present invention can secure a low coherence that can solve the problem of rainbow stains, and is an easily adhesive polyester with excellent adhesion to various functional layers, blocking resistance, and transparency. It's about the film. More specifically, the present invention relates to a self-adhesive polyester film that can be suitably used in high-definition optical applications.

A hard coat film obtained by laminating a transparent hard coat layer is used on the front surfaces of displays, decorative materials, etc., such as touch panels, computers, televisions, and liquid crystal displays. Moreover, as a transparent plastic film of a base material, a transparent polyester film is generally used, and in order to improve the adhesion between the polyester film of the base material and the hard coat layer, it has an adhesive property as an intermediate layer of these. Often, a coating layer is provided.

The hard coat film is required to have temperature, humidity, light resistance, transparency, chemical resistance, scratch resistance, antifouling properties, and the like. Moreover, since it is often used for surfaces such as displays and decorative materials, visibility and design are required. Therefore, in order to suppress glare, iris color, etc. due to reflected light when viewed from an arbitrary angle, a multi-layered 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 an antireflection layer.

However, in applications such as displays and decorative materials, in recent years, further large screens (large areas) and high definitions are required, and as a result, the required level of suppression of iris color (interference stain), particularly under fluorescent lamps, is required. It has been rising. In addition, for fluorescent lamps, the three-wavelength type has been mainstream for reproducibility of the main light color, so that interference spots are more likely to appear. In addition, the demand for cost down by simplifying the antireflection layer has also increased. For this reason, it is desired to suppress interference unevenness as much as possible even with a hard coat film without adding an antireflection layer.

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, the portable device is mostly a display by a liquid crystal panel in view of thinning. In such a field, for example, in a mobile phone equipped with a touch panel, as a hard coat film for protecting the surface of a display, a hard coat film such as an interference pattern or an icon sheet caused by reflected light on both surfaces contacting an application surface is used. In applications where design is applied to the back surface, the defect of visibility due to interference fringe is more present.

The iris-like color (interference stain) of the hard coat film has a large difference between the refractive index (for example, 1.62 to 1.65) of the polyester film of the base material and the refractive index (for example, 1.49) of the hard coat layer made of acrylic resin or the like. It is said that it occurs because. In order to reduce the difference in refractive index between the layers and prevent the occurrence of interference stains, a relatively high refractive index coating layer is provided on the polyester film of the substrate, and the difference in refractive index between the polyester film and the coating layer, the coating layer and the hard coat layer A method of reducing the difference in refractive index of has been proposed.

Conventionally, in the field of the optically easy-to-adhesive film, as a method of increasing the refractive index of the easily-adhesive layer, a method of including specific high refractive index fine particles in the coating layer, a method of increasing the refractive index of the resin of the coating layer, and the like are known. In particular, a polyester resin using a naphthalenedicarboxylic acid component as a copolymerization component of naphthalenedicarboxylic acid is also excellent in adhesion to a base polyester film, and has been proposed as a suitable example (see, for example, Patent Document 1). However, in general, a polyester resin having a high refractive index has a high glass transition temperature and poor adhesiveness due to lack of flexibility of the resin, or a problem in that the blocking resistance deteriorates when the polyester resin is increased. . 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, see Patent Document 2), and Patent Document 1 also blends a polyurethane resin having a polycarbonate component. Although it does, there is a problem in that if the number of polyurethane components is increased, low coherence and transparency are deteriorated. Thus, conventionally, a self-adhesive polyester film having all of the adhesion to the hard coat layer, blocking resistance, and transparency at a high balance, while meeting the recent high level of low coherence, has not been obtained.

Japanese Patent Application No. 2011-246663 Japanese Patent Application No. 2011-168053

This invention is made | formed on the background of the subject of such a prior art. That is, the object of the present invention is excellent in any of low coherence that can suppress rainbow stains, adhesion to a hard coat layer or the like required for a high level in various optical uses, blocking resistance, transparency, and furthermore, high It is to provide a self-adhesive polyester film which has a slip property and can be suitably used in optical applications having excellent handling properties in a post-process such as a manufacturing process or 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 where the coating layer containing the polyurethane resin having a polycarbonate skeleton and the polyester resin having a naphthalene skeleton on at least one side of the polyester film is 100% by mass of the coating layer solid content. When the content (mass%) of a is shown in the triangular diagram as 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 shown in c, a, b , c is a self-adhesive polyester film in a region surrounded by four straight lines of 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%, c is 35 mass%, 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%, c is 80 mass%, 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%, c is 20 mass%, 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%, c is 10 mass%, a is 10 mass%, b is 55 mass%, and c is 35 mass%

2. The easily-adhesive polyester film according to the above 1, wherein the coating layer contains a crosslinking agent.

3. The easily-adhesive polyester film according to the first or the second, wherein the coating layer contains metal oxide particles (particle A) having a refractive index of 1.7 or more.

4. The easily-adhesive polyester film according to any one of the first to third, wherein the coating layer contains lubricant particles (particles B).

5. One or more functions selected from the group consisting of a hard coat layer, an anti-glare layer, an anti-glare anti-reflective layer, an anti-reflective layer and a low-reflective layer on the coating layer of the easily-adhesive polyester film according to any one of the above 1 to 4 A laminated polyester film with layers.

According to the present invention, the low-interference, transparency, blocking resistance, adhesiveness with various functional layers, and slipperiness that can suppress rainbow stains are excellent, and the adhesive film of an easily-adhesive polyester film can be suitably used in optical applications. Provision was made possible.

1 is a triangular diagram showing a preferable range in the easily-adhesive polyester film of the present invention.

(Polyester film)

The polyester film used as the base material in the present invention is a film composed of a polyester resin, and is mainly composed of 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 a copolymerized polyester in which the 3rd component monomer was copolymerized with the polyester as mentioned above may be sufficient. Among these polyester films, a polyethylene terephthalate film is most preferred from the balance of physical properties and cost.

Moreover, the said polyester film may be a single layer or a multilayer. Moreover, as long as it is in the range which shows the effect of this invention, each additive can contain various additives in a polyester resin as needed. Examples of the additives include antioxidants, light fasteners, antigelling agents, organic wetting agents, antistatic agents, ultraviolet absorbers, surfactants, and the like.

(Coating layer)

In the easily-adhesive polyester film of the present invention, an easily-adhesive coating layer is laminated on the polyester base film as described above.

In the coating layer in the present invention, the content (mass%) of a polyurethane resin component having a polycarbonate skeleton when the total amount of coating layers (solid content) is 100 mass% is a, a polyester resin component having a naphthalene skeleton. When content (mass%) is represented as a triangular diagram with b and the total amount (mass%) of components other than these as c, a, b, and c are four straight lines of straight line P1, straight line Q1, straight line R1, and straight line S1. It is preferably within the range of the area surrounded by.

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%, c is 35 mass%, 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%, c is 80 mass%, 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%, c is 20 mass%, 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%, c is 10 mass%, a is 10 mass%, b is 55 mass%, and c is 35 mass%

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

The above-described preferred range will be briefly described using the triangular diagram shown in FIG. 1. The coordinate axes of 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 other components c (mass%) on the three sides of the triangular diagram Respectively. Here, if the coordinates in the triangular table are written in order of (a, b, c), the five coordinates (10, 55, 35), (10, 10, 80), (70, 10, 20), (50, 40, 10) and (45, 45, 10) are shown. Then, straight lines P1 passing through (10, 55, 35) and (10, 10, 80), straight lines passing through (10, 10, 80) and (70, 10, 20) Q1, (70, 10, 20) ) And four straight lines of a straight line R1 passing through (50, 40, 10), and a straight line S1 passing through (45, 45, 10) and (10, 55, 35), surrounded by the four straight lines The inner range represents a range in which low interference (interference pattern improvement), adhesion, blocking resistance, and transparency can be provided in a good balance.

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

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 adopt a straight line passing through).

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

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

Instead of the straight line S1, the straight line S2 (point where a is 50 mass%, b is 40 mass%, c is 10 mass%, a is 10 mass%, b is 50 mass%, and c is 40 mass%) A straight line passing through), furthermore, a straight line S3 (a is 52% by mass, b is 38% by mass, c is 10% by mass, a is 10% by mass, b is 48% by mass, and c is 42% by mass) A straight line passing through), particularly S4 (a is 55% by mass, b is 35% by mass, c is 10% by mass, a is 10% by mass, b is 45% by mass, and c is 45% by mass) It is preferable to adopt a straight line passing through).

The lower limit of the content a of the polyurethane resin component having a polycarbonate skeleton is preferably 10 mass%, more preferably 13 mass%, and even more preferably 15 mass%. When the content a of the polyurethane resin component having a polycarbonate skeleton is 10% by mass or more, transparency is not impaired, and adhesion is satisfactory, which is preferable.

The upper limit of the content a of the polyurethane resin component having a polycarbonate skeleton is preferably 70 mass%, more preferably 60 mass%, further preferably 50 mass%, particularly preferably 40 mass%. When the content a of the polyurethane resin component having a polycarbonate skeleton is 70 mass% or less, the refractive index is maintained high, and low coherence is obtained, which is preferable.

The lower limit of the content b of the polyester resin component having a naphthalene skeleton is preferably 10% by mass, more preferably 15% by mass, and even more preferably 20% by mass. When the content b of the polyester resin component having a naphthalene skeleton is 10% by mass or more, adhesiveness is satisfied and is preferable.

The upper limit of the content b of the polyester resin component having a naphthalene skeleton is preferably 55% by mass, more preferably 50% by mass, further preferably 48% by mass, particularly preferably 45% by mass. When the content b of the polyester resin component having a naphthalene skeleton is 55% by mass or less, blocking resistance is exhibited, which is preferable.

The lower limit of the content c of other components is preferably 10% by mass, more preferably 20% by mass, further preferably 25% by mass, particularly preferably 30% by mass. When the content c of the other components is 10% by mass or more, a low-interference property is improved when a component that increases the refractive index of the coating layer is included, which is preferable. Moreover, as a result, since content a of the polyurethane resin which has a polycarbonate skeleton does not become too large, blocking can be prevented, it is preferable.

The upper limit of the content c of other components is preferably 80% by mass, more preferably 70% by mass, further preferably 60% by mass, particularly preferably 55% by 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 preferable because it is easy to balance the blocking resistance and the refractive index (low interference).

(Polyurethane resin having a polycarbonate skeleton)

It is preferable to contain the aliphatic polycarbonate polyol excellent in heat resistance and hydrolysis resistance in the diol component which is a component of the polyurethane resin having a polycarbonate skeleton. In the optical use of the present invention, it is preferable to use an aliphatic polycarbonate polyol from the viewpoint of preventing yellowing.

Examples of the aliphatic polycarbonate polyol include an aliphatic polycarbonate diol, an aliphatic polycarbonate triol, and the like, and an aliphatic polycarbonate diol can be preferably 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 Aliphatic polycarbonate diol obtained by reacting 1 or 2 or more types of diols, such as, 4-cyclohexane dimethanol, and carbonates, such as dimethyl carbonate, diphenyl carbonate, ethylene carbonate, and phosgene. Can be lifted.

A polyurethane resin having a polycarbonate backbone is the ratio of the aliphatic polycarbonate component derived from the vicinity of 1460cm ^-1 of the absorbance (A1460) and the urethane components absorbance (A1530) in the vicinity of 1530cm ^-1 derived as measured by infrared spectroscopy (A1460 / It is preferable that A1530) be 0.40 to 2.30.

When the ratio (A1460 / A1530) is 0.40 or more, it is preferable that the hard urethane component does not increase too much, the stress relaxation of the coating layer is not lowered and there is no fear that the heat and moisture resistance is lowered. Moreover, when the said ratio (A1460 / A1530) is 2.30 or less, since the aliphatic component of a flexible aliphatic polycarbonate does not become too large, the solvent resistance of a coating layer is maintained and there is no fear that moisture-heat resistance will fall, and it is preferable.

In order to set the ratio (A1460 / A1530) in the range of 0.40 to 2.30, the number average molecular weight of the aliphatic polycarbonate diol is preferably 1500 to 4000, and more preferably 2000 to 3000. When the number average molecular weight of the aliphatic polycarbonate diol is small, the proportion of the aliphatic polycarbonate component constituting the urethane resin is relatively small.

As the 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 (isocyanatemethyl) cyclohexane, aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylenediisocyanate, or compounds thereof, in trimethylolpropane in single or plural And polyisocyanates previously added. The polyisocyanates described above are preferable for optical applications, which do not have a problem of yellowing and require high transparency. Moreover, these polyisocyanates are preferable because the coating film does not become too hard, and stress due to shrinkage and swelling of a photocurable resin or the like can be relieved, and adhesion is maintained.

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

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 and 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, and tri-n-butylamine, N-methylmorpholine, and N- N-alkyl morpholines such as ethyl morpholine, N-dialkyl alkanolamines such as N-dimethylethanolamine and N-diethylethanolamine. These can be used alone or in combination of two or more.

In order to provide 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 100 mol%, it is preferable that it is 3-60 mol%, and it is preferable that it is 5-40 mol%. When the composition molar ratio is 3 mol% or more, water dispersibility is good and is preferable. Moreover, when the said composition molar ratio is 60 mol% or less, it is preferable because water resistance is maintained and moisture and heat resistance are maintained.

The glass transition point temperature of the urethane resin of the present invention is preferably less than 0 ° C, more preferably less than -5 ° C. When the glass transition point temperature is less than 0 ° C, it is preferable because it is easy to exhibit suitable flexibility from the viewpoint of stress relaxation of the coating layer.

(Polyester resin having a naphthalene skeleton)

By containing a component derived from naphthalenedicarboxylic acid as the acid component of the polyester resin contained in the coating layer, the refractive index is increased and it becomes easy to control the iris color under fluorescent light. In addition, it becomes possible to improve the moisture heat resistance.

As such a naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid is preferable. The proportion of the naphthalenedicarboxylic acid in all dicarboxylic acid components constituting the polyester resin is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 50 mol% or more, and 60 mol% or more It is more preferable.

Moreover, if it is the range which shows the effect of this invention, it is further added as an acid component in a polyester resin, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 1,4-cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, dimer 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 the aromatic dicarboxylic acid component is 70 mol% or more, and further 80 mol% or more, including naphthalenedicarboxylic acid from the viewpoint of heat resistance and high refractive resistance. In particular, when emphasizing heat resistance and high refractive resistance, the aromatic dicarboxylic acid component is preferably 90 mol% or more, and more preferably 95 mol% or more, particularly 100%.

If it is within the range showing the effect of the present invention, as the diol component in the polyester resin, ethylene glycol, 1,3-propane glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, di Ethylene glycol, 1,4-cyclohexanedimethanol, xylene glycol, and ethylene oxide adducts of bisphenol A may be used.

Moreover, when the content of the polyurethane resin having a polycarbonate skeleton in the coating layer is reduced, the flexibility of the coating film deteriorates, and there is a concern that the coating layer may be cut or particles may be dropped due to post-treatment. In such a case, it is one of the preferable forms that the polyester resin contains a dicarboxylic acid component represented by the following formula (1) and / or a diol component represented by the following formula (2).

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

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

As described above, by containing an acid component and / or a diol component having a carbon component of a specific length, the polyester resin is provided with flexibility, and it is easy to maintain even if the particles are relatively large, thereby suppressing chipping of the coating layer and dropping of the particles. can do.

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

The polyester resin is water or water-soluble organic solvent (for example, an aqueous solution containing less than 50% by mass of alcohol, alkylcellosolve, ketone-based, ether-based) or organic solvent (for example, toluene, acetic acid ( Iii) dissolved or dispersed in ethyl).

When a polyester resin is used as the aqueous coating solution, a water-soluble or water-dispersible polyester resin is used, but for such water solubilization or water oxidation, a sulfonate group-containing compound or a carboxylate group is included. It is preferable to copolymerize the said compound.

The number average molecular weight of the polyester resin is preferably 5000 to 40000 from the viewpoint of coating film strength and ease of dispersion. More preferably, it is 10000 to 30000, and particularly preferably 12000 to 25000.

Moreover, the polyester resin containing a naphthalenedicarboxylic acid component may be a single thing, or may be a mixture of two or more. When it is a mixture of 2 or more types, it is preferable that it is said composition as a total of a polyester resin component.

Other components contained in the coating layer include binder resins, crosslinking agents, lubricant particles, and refractive index of the coating layer other than the polyester resin containing a polyurethane resin or a naphthalenedicarboxylic acid component having a polycarbonate skeleton. The height may include metal oxide particles, surfactants, and the like, but in the present invention, it is preferable to contain crosslinking agents, lubricant particles, and metal oxide particles that increase the refractive index of the coating layer. Although a solvent may be included in the coating liquid, and a surfactant may be included, the mass of the solvent remaining after drying and curing or the solid content of the surfactant is very small, and when calculating the composition of each component by calculation from the coating liquid , The mass of the residual solvent and the mass of the solid content of the surfactant need not necessarily be included in the mass of the solid content of the entire coating layer, and the description of the composition of the examples is based on the above calculation.

In order to form a crosslinked structure in the coating layer, the coating layer may be formed by containing a crosslinking agent. By containing a crosslinking agent, it becomes possible to further improve the adhesion under high temperature and high humidity. Specific examples of the crosslinking agent include urea-based, epoxy-based, melamine-based, isocyanate-based, oxazoline-based, and carbodiimide-based. Of these, melamine-based, isocyanate-based, oxazoline-based, and carbodiimide-based crosslinking agents are preferred from the time-lapse stability of the coating solution and the effect of improving the adhesion under high temperature and high humidity treatment. Moreover, a catalyst etc. can be used suitably as needed in order to accelerate a crosslinking reaction.

When a crosslinking agent is comprised in the coating layer, the content of the crosslinking agent is preferably 5% by mass or more and 50% by mass or less among all the solid components of the coating layer. More preferably, it is 10 mass% or more and 40 mass% or less. If it is 10 mass% or more, the strength of the resin of the coating layer is maintained, and the adhesiveness under high temperature and high humidity is good, and when it is 40 mass% or less, the flexibility of the resin of the coating layer is maintained, and the adhesiveness under normal temperature and high temperature and high humidity is maintained, which is preferable. Do.

Moreover, it is preferable to contain the metal oxide particle (particle A) of a high refractive index with a refractive index of 1.7 or more in a coating layer. Such metal oxides include 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), etc., and composite oxide particles containing these metal atoms.

The lower limit of the refractive index of the particle A is preferably 1.7, and more preferably 1.75. The upper limit of the refractive index of the particle A is preferably 3.0, more preferably 2.7, and even more preferably 2.5. By setting the above range, it is possible to satisfactorily balance the low coherence, transparency, adhesion, and blocking resistance.

The composite oxide particles used as particle A are preferably TiO ₂ / ZnO particles (zirconia / titania mixed particles). A zirconia / titania mixed particle is 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 to form no complex. Of course, in the coating layer, the liquid component is almost evaporated and disappears in the drying step or the curing step. When the coating layer contains such a particle A, the balance of slipperiness and transparency is excellent, and high transparency and low coherence can be ensured. The liquid is preferably a water-based liquid in order to easily form a coating layer by a so-called in-line coating method described later.

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

It is preferable that the average particle diameter of particle 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 is preferable.

The average particle diameter of the particles A is preferably 200 nm or less, more preferably 150 nm or less, further preferably 100 nm or less, and particularly preferably 60 nm or less. When the average particle diameter of the particle A is 200 nm or less, transparency is good and is preferable.

In the present invention, it is preferable to contain the lubricant particles (particles B) in the coating layer.

Particle B is (1) silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, satin white, aluminum silicate, diatomaceous earth , Inorganic particles such as calcium silicate, aluminum hydroxide, hydrolyzed halosite, magnesium carbonate, and magnesium hydroxide, (2) acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene / acrylic, styrene / butadiene , Polystyrene / acrylic, polystyrene / isoprene, polystyrene / isoprene, methylmethacrylate / butylmethacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol, diallylphthalate, poly Although organic particles, such as an ester system, are mentioned, silica is especially preferably used in order to provide moderate slipperiness to a coating layer.

The average particle diameter of the particles B is preferably 200 nm or more, more preferably 250 nm or more, further preferably 300 nm or more, and particularly preferably 350 nm or more. When the average particle diameter of the particles B is 200 nm or more, it is difficult to aggregate, and it is preferable because it is possible to secure slipping properties.

The average particle diameter of the particles B is preferably 2000 nm or less, more preferably 1500 nm or less, further preferably 1000 nm or less, and particularly preferably 700 nm or less. When the average particle diameter of the particles B is 2000 nm or less, transparency is maintained, and the particles are not eliminated.

Surface treatment of the particles A and B may be performed, and the surface treatment method includes physical surface treatment such as plasma discharge treatment and corona discharge treatment, and chemical surface treatment using a coupling agent, but the use of a coupling agent is preferred. As the coupling agent, an organoalkoxy metal compound (for example, titanium coupling agent or silane coupling agent) is preferably used. Silane coupling treatment is particularly effective when the particle B is silica. As the surface treatment agent of the particle B, it may be used to perform the surface treatment in advance before preparing the layer coating liquid, or it may be added as an additive when the layer coating liquid is prepared and contained in the layer. Of course, you may use for particle A.

It is preferable that content of the particle A in a coating 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. When the content of the particle A in the coating layer is 2% by mass or more, the refractive index of the coating layer can be maintained high, and low coherence is effectively obtained and is preferable.

The content of the particles A in the coating layer is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, and particularly preferably 20% by mass or less. When the content of the particle A in the coating layer is 50% by mass or less, film formability is maintained and is preferable.

It is preferable that content of the particle B in a coating 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 the content of the particle B in the coating layer is 0.01% by mass or more, proper sliding property is maintained and is preferable.

It is preferable that content of the particle B in a coating layer is 2 mass% or less, More preferably, it is 1.5 mass% or less, More preferably, it is 1 mass% or less. When the content of the particle B in the coating layer is 2% by mass or less, the haze is kept low, which is preferable from the viewpoint of transparency.

The thickness of the coating layer is preferably 0.001 µm or more, more preferably 0.01 µm or more, further preferably 0.02 µm or more, and particularly preferably 0.05 µm or more. When the film thickness of the coating layer is 0.001 µm or more, adhesiveness is good and is preferable.

The film thickness of the coating layer is preferably 2 µm or less, more preferably 1 µm or less, further preferably 0.8 µm or less, and particularly preferably 0.5 µm or less. When the film thickness of the coating layer is 2 µm or less, there is no fear of blocking, which is preferable.

The coating layer may also contain a surfactant for the purpose of improving leveling properties during application and defoaming the coating solution. The surfactant may be any of cationic, anionic and nonionic surfactants, but silicone, acetylene glycol or fluorine surfactants are preferred. It is preferable to include these surfactants in the coating layer within a range that does not impair the effect of suppressing the iris-like color under the fluorescent lamp or adhesion.

In order to impart different functionality to the coating layer, various additives may be contained within a range that does not impair the suppression effect or adhesion of the iris color under a fluorescent lamp. Examples of the additives include fluorescent dyes, fluorescent brighteners, plasticizers, ultraviolet absorbers, pigment dispersants, defoamers, defoamers and preservatives.

As the coating method, both the so-called in-line coating method to simultaneously coat the polyester substrate film and the so-called offline coating method to coat the polyester substrate film with a separate coater can be applied, but the in-line coating method is more efficient and more efficient. desirable.

As the coating method, any method known in the art can be used as a method for applying the coating liquid to a polyethylene terephthalate (hereinafter abbreviated 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 the present invention, as a method of providing a coating layer on a polyester film, a method of coating and drying a coating solution containing a solvent, particles, and resin on a polyester film is mentioned. Examples of the solvent include an organic solvent such as toluene, water, or a mixed system of water and a water-soluble organic solvent. Preferably, water is mixed with water alone or a water-soluble organic solvent in view of environmental problems. .

The solid content concentration of the coating solution varies depending on the type of the binder resin, the type of the solvent, and the like, but is preferably 2% by mass or more, and more preferably 4% by 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 coating also varies depending on the type of the binder resin, the type of the 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, and is preferably 0.01 nm or more, more preferably 0.1 nm or more, still more preferably 0.2 nm or more, and particularly preferably 0.5 nm or more. On the other hand, the upper limit of the surface roughness (Ra) of the coating layer is preferably 200 nm or less, more preferably 100 nm or less, still more preferably 80 nm or less, and particularly preferably 50 nm or less.

(Preparation of optically-adhesive polyester film)

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 melt | dissolving a polyester resin and extruding into a sheet shape, the unoriented polyester molded is stretched in the longitudinal direction using the speed difference of a roll at a temperature more than a glass transition temperature, and then a tenter. The method of extending | stretching in a horizontal direction by this, and performing heat processing is mentioned.

The polyester film of the present invention may be a uniaxially stretched film or a biaxially stretched film, but when a biaxially stretched film is used as a protective film on the entire surface of a liquid crystal panel, even if it is observed directly above the film surface, a rainbow color unevenness is not seen. Color observation on the rainbow may be observed when observed from the oblique direction, so care must be taken.

This phenomenon is that the biaxially stretched film is composed of a refractive index ellipsoid having different refractive indices in the running direction, the width direction, and the thickness direction, so that the in-plane retardation becomes zero by the light transmission direction inside the film (the refractive index ellipsoid is a true circle) This is because the visible direction exists. Therefore, when the liquid crystal display screen is observed from a specific direction in the oblique direction, a point in which in-plane retardation becomes zero may be generated, and a rainbow color unevenness occurs concentrically around the point. Then, when the angle from the top of the film surface (normal direction) to the position where the color unevenness of the rainbow is visible is θ, this angle θ increases as the birefringence in the film surface increases, making it difficult to see the color unevenness of the rainbow. Since the angle θ tends to be small in the biaxially stretched film, the rainbow color unevenness is more likely to be seen in the uniaxially stretched film.

However, in a complete uniaxial (uniaxially symmetrical) film, mechanical strength in the direction perpendicular to the direction of orientation is significantly lowered, which is not preferable. It is preferable that the present invention has biaxiality (biaxial objectivity) in a range that does not substantially generate rainbow color unevenness, or within a range that does not generate rainbow color unevenness in a 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 an ultraviolet curable acrylic resin, a siloxane-based thermosetting resin, or the like on the coating layer of the easily adhesive polyester film of the present invention. It is obtained by installing.

It is also a preferred form to provide a functional layer on the coating layer of the easily adhesive polyester film of the present invention. The functional layer is for the purpose of preventing glare, suppressing glare, suppressing rainbow stains, and suppressing scratches. In addition to the above-mentioned hard coat layer, functional layers such as an anti-glare layer, an anti-glare anti-reflective layer, an anti-reflective layer, a low-reflection layer, and an anti-static layer It refers to the layer to have. As the functional layer, various kinds of known ones can be used in the technical field, and the type is not particularly limited. Hereinafter, each functional layer is demonstrated.

For example, a known hard coat layer can be used for the formation of the hard coat layer, and is not particularly limited, but polymerization, and / or reaction is performed by drying, heat, chemical reaction, or irradiation with electron beam, radiation, or ultraviolet rays. A resin compound to be used can be used. Examples of the curable resin include melamine-based, acrylic-based, silicone-based, and polyvinyl alcohol-based curable resins, but photocurable acrylic-based curable resins are preferred 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 can be used, and examples of the acrylate-based oligomer include polyester acrylate, epoxy acrylate, and urethane acrylate. , Polyether acrylate-based, polybutadiene acrylate-based, and silicone acrylate-based. A coating composition for forming the optical functional layer can be obtained by mixing a reaction diluent, a photopolymerization initiator, and a sensitizer with these acrylic curable resins.

The hard coat layer may have an anti-glare function (anti-glare function) that 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, the haze of the film is preferably 0 to 50%, more preferably 0 to 40%, particularly preferably 0 to 30%. Of course, 0% is ideal and may be 0.2% or more, or 0.5% or more.

For this reason, the use of the film of the present invention is mainly for the overall optical film, such as prism lens sheet, AR (anti-reflection) film, hard coat film, diffusion plate, shatterproof film, LCD, flat TV, CRT, etc. It can be suitably used for a base film of an optical member, a near-infrared absorption filter which is a member on a front panel for a plasma display, a transparent conductive film such as a touch panel or electroluminescence.

More specifically, the acrylic resin cured by the electron beam or ultraviolet rays for forming the hard coat layer, which has an acrylate-based functional group, for example, a relatively low molecular weight polyester resin, polyether resin, acrylic resin. Oligomers or prepolymers such as (meth) acrylates of polyfunctional compounds such as epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiolpolyene resins, polyhydric alcohols, and ethyl (meth) as reactive diluents Monofunctional and polyfunctional monomers such as acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, and N-vinylpyrrolidone, such as trimethylolpropane tri (meth) acrylate, hexanediol (meth ) Acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pen Pentaerythritol tri (meth) it may be used containing an acrylate, and dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate.

However, in the case of electron beam or UV curable resins, acetophenones, benzophenones, mihilabenzoylbenzoate, α-amyloxime esters, tetramethylthiuram monosulfide, thioxanthone as photopolymerization initiators in the above-mentioned resins It can be used by mixing n-butylamine, triethylamine, tri-n-butylphosphine or the like as a sensitizer or a photosensitizer.

In addition, a silicone-based (siloxane-based) thermosetting resin can be produced by mixing an organosilane compound alone or in combination of two or more under an acid or base catalyst, followed by hydrolysis and condensation reaction. In particular, in the case of low anti-use, it is better to improve the low refractive index, fouling resistance, and the like by mixing one or more fluorosilane compounds for hydrolysis and condensation reaction.

(Production of laminated polyester film)

The method for producing the laminated polyester film in the present invention will be described using an easily-adhesive polyester film as an example, but of course it is not limited to this.

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

In this invention, it is preferable that the thickness of a hard-coat layer is 1-15 micrometers. When the thickness of the hard coat layer is 1 µm or more, the effects on the chemical resistance, scratch resistance, and antifouling properties as the hard coat layer are efficiently exhibited, which 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, etc., which is preferable.

As the scratch resistance, when the coated surface is worn with black ground, it is preferable that the scratches are not noticeable with the naked eye. If the scratch is noticeable in the above evaluation, it is difficult to be scratched when passing through the guide roll, and it is preferable from the viewpoint of handling properties and the like.

The lower limit of the static friction coefficient (㎲) is preferably 0.3, and if it is 0.3 or more, there is no problem of slipping, so it is easy to wind up with a roll of hard chrome plating or the like in the manufacturing process, and maintains handling and blocking resistance. It is preferred. The upper limit of the static friction coefficient (㎲) is preferably 0.5, and if it is 0.5 or less, it is preferable because there is no fear of scratching the film serving as a contact surface when rolling up.

The lower limit of the kinetic friction coefficient (μd) is preferably 0.4, and if it is 0.4 or more, there is no problem of slipping, so that it is easy to wind up with a roll of hard chrome plating or the like in the manufacturing process, and maintains handling and blocking resistance. It is preferred. The upper limit of the coefficient of kinetic friction (μd) is preferably 0.6, and if it is 0.6 or less, it is preferable because there is no fear of scratching the film that becomes the contact surface when it is rolled up.

Since the polyester film of this invention is mainly used as an optical easily adhesive film, it is preferable to have high transparency. The lower limit of haze is ideally 0%, and the closer it is 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 the liquid crystal display device, which is preferable. The haze of the polyester film can be measured, for example, according to a method described later.

The adhesiveness between the easily-adhesive coating layer and the hard coat layer is preferably 80%, and the upper limit is preferably 100% by evaluation by a measurement method described later. If it is 80% or more, it can be said that the adhesiveness between the coating layer and the hard coat layer is sufficiently maintained.

With respect to the adhesion between the easily-adhesive layer and the hard coat layer evaluated under the method described below under high temperature and high humidity conditions, the lower limit is preferably 10%, and the upper limit of the high temperature and high humidity adhesion is preferably 100%. If it is 10% or more, the adhesiveness between the easily-adhesive layer and the hard coat layer is satisfactory under high temperature and high humidity conditions, and the passability in the post-processing step is satisfactorily satisfied. More preferably, it is 50% or more.

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

The easily-adhesive polyester film of the present invention can be used in various applications, but is preferably used in the manufacturing process of a polarizing plate used in a liquid crystal display device, and is particularly preferably used as a protective film of a polarizer constituting the polarizing plate. . Usually, the polarizer is often made of polyvinyl alcohol, and the easily-adhesive polyester film of the present invention is bonded to the polarizer using an adhesive in which a polyvinyl alcohol agent or a crosslinking agent is added thereto. In that case, it is more preferable to use the coating layer of the easily-adhesive polyester film of the present invention toward the opposite side, not the side of the side to be adhered to the polarizer. The surface to be adhered to the polarizer of the easily-adhesive polyester film of the present invention includes, for example, a polyester-based resin, a polyvinyl alcohol-based resin and a crosslinking agent as described in International Publication No. 2012/105607. It is preferable that the adhesive layer is laminated.

Example

Next, the present invention will be described in detail using Examples, Comparative Examples and Reference Examples, but the present invention is of course not limited to the following Examples. In addition, the evaluation method used in the present invention is as follows.

(1) Average particle diameter

[Measurement method using a scanning electron microscope]

The average particle diameter of the particles can be measured by the following method. Take a photo of a particle with a scanning electron microscope (SEM), and measure the maximum diameter (distance between the two most distant points) of 300 to 500 particles at a magnification such that the size of one of the smallest particles becomes 2 to 5 mm. , The average value is taken as the average particle diameter. The average particle diameter of the particles present in the coating layer in the present invention can be measured by the above measuring method.

[Dynamic light scattering method]

The average particle diameter of the particles can also be determined by dynamic scattering in the production of particles or films. The sol was diluted with a dispersion medium, measured by a submicron particle analyzer N4 PLUS (manufactured by Beckman-Culter) using the parameters of the dispersion medium, and calculated by a cumulant method to obtain an average particle diameter. In the dynamic light scattering method, the average particle diameter of the particles in the sol is observed, and when there is aggregation between the particles, the average particle diameter of these aggregated particles is observed.

(2) Refractive index of particles

The refractive index of the particles can be measured by the following method. After drying the inorganic particles at 150 ° C., the powder crushed in a mortar is immersed in solvent 1 (which has a lower refractive index than the particles), and then a small amount of solvent 2 (which has a higher refractive index than the particles) becomes almost transparent. Until it was added. The refractive index of this solution was measured using an Abbe's refractometer (Abbe's Refractometer manufactured by Atago Co., Ltd.). The measurement was carried out at 23 ° C with a D line (wavelength 589 nm). The solvent 1 and the solvent 2 are selected to be mixed with each other, and according to 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 according to JIS K 7136: 2000 using a turbidity meter (manufactured by Nippon Denshoku, NDH2000).

(4) Adhesion

On the easily-adhesive layer of the polyester film obtained in the Examples, the hard coat layer described in the section on forming the hard coat layer described above was formed. The adhesive film of the hard coat layer and the base film is calculated | required according to the base material of 8.5.1 of JIS-K5400-1990, the polyester film for easy adhesion which formed the hard coat.

Specifically, 100 checkered cuts that penetrate the hard coat layer and reach the base film are adhered to the hard coat layer surface using a cutter guide having a clearance of 2 mm. Subsequently, a cellophane adhesive tape (manufactured by Nichiban, No. 405; width of 24 mm) was applied to the cut surface on a checkerboard, and rubbed with an eraser to completely adhere. Thereafter, the cellophane adhesive tape was vertically removed from the hard coat layer surface of the hard coat laminated polarizer protective film, and the number of checkerboards peeled from the hard coat layer surface of the hard coat laminated polarizer protective film was visually counted, and the hard coat layer and The adhesion with the base film is determined. In addition, the partially peeled board is counted as a peeled board.

Adhesion (%) = {1- (Number of peeled checkerboard / 100)} × 100

(5) Improvement of interference fringes (iris color)

A 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 forming the hard coat was cut out to an area of 10 cm (film width direction) x 15 cm (film length direction) to prepare a sample film. A black glossy tape (made by Nitto Denko Co., Ltd., vinyl tape No21; black) was pasted on the surface opposite to the hard coat layer surface of the obtained sample film. Using the hard coat surface of this sample film as the top surface, using a three-wavelength main white color (National Paruk, FL 15EX-N 15W) as a light source, the positional relationship (the distance from the light source) where the reflection is most visible to the naked eye from above the diagonal 40-60 cm, 15-45 °).

The results observed with the naked eye are ranked according to the following criteria. In addition, observation is performed with five persons familiar with the evaluation, and the most rank is the evaluation rank. For example, in the case of being equal to two ranks, the center of the rank divided into three was employed. For example, ◎ and ○ are 2 each, △ is 1, ○ is 1, ◎ is 1, ○ and △ are 2, respectively, ◎ and △ are 2 each, and ○ is 1 In this case, ○ is adopted.

◎: The color of the iris is not visible even when viewed from all angles.

○: Iris color can be seen depending on the angle.

(Triangle | delta): Iris color is observed slightly.

×: A distinct iris color was observed.

(6) Blocking resistance

The coated surfaces of the two laminated films were overlapped so as to face each other, a load of 5 kg / cm 2 was applied, and this was left for 24 hours in an atmosphere of 50 ° C. The superimposed film was peeled off, and the peeling state was determined based on the following criteria.

◎: can be peeled lightly

(Circle): There is resistance at the time of peeling, but the coating layer does not transfer to the other surface.

(Triangle | delta): The peeling sound is produced | generated, and the coating layer partially transfers to the counter surface

X: Two films are stuck and cannot be peeled off, or even if peeling is possible, the base film is split and cracked

(7) Glass transition temperature

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

(8) Number average molecular weight

Dissolve 0.03 g of resin in 10 ml of tetrahydrofuran, and use GPC-LALLS 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 the minute and column (shodex KF-802, 804, 806 by Showa Denko).

(9) Resin composition

The resin was dissolved in heavy chloroform, and 1H-NMR analysis was performed using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian Inc. to determine the mole percent ratio of each composition from the integral ratio.

(Polymerization of polyester resin)

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

To a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux cooler, 342.0 parts by mass of 2,6-naphthalenedicarbonic acid dimethyl, 35.0 parts by mass of dimethyl terephthalate, 35.5 parts by mass of dimethyl-5-sodium sulfoisophthalate , 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 added, and the transesterification reaction was performed from 160 ° C to 220 ° C over 4 hours. Further, 60.7 parts by mass of sebacic acid was added to carry out an esterification reaction. Subsequently, the temperature was raised to 255 ° C., the reaction system was gradually reduced in pressure, and then reacted for 1 hour and 30 minutes under a reduced pressure of 30 Pa to obtain a copolymerized polyester resin (B1). The obtained copolymerized polyester resin was pale yellow transparent.

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

Moreover, the raw material was changed and the copolymer polyester resins (B2) and (B3) of the composition shown in Table 1 were obtained likewise.

[Table 1]

(Preparation of polyester water dispersion)

In a reactor equipped with a stirrer, a thermometer and a reflux device, 30 parts by mass of the copolymerized polyester resin (B1) and 15 parts by mass of ethylene glycol-n-butyl ether were added, heated and stirred at 110 ° C to dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was slowly added to the polyester solution while stirring. After the addition, the solution was cooled to room temperature while stirring to prepare a milky white polyester water dispersion (Bw1) having a solid content of 25% by mass.

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

(Preparation of polyurethane water dispersion)

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

In a four-necked flask equipped with a stirrer, a load rod cooler, a nitrogen introduction 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, poly with 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 the mixture was stirred for 3 hours at 75 ° C under a nitrogen atmosphere, and the reaction solution reached a predetermined amine equivalent weight. I confirmed it. Next, after incubating the reaction solution to 40 ° C, 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and stirred and mixed at 2000 min ⁻¹ , followed by adding a polyurethane prepolymer solution and dispersing it in water. Thereafter, a part of acetone and water was removed under reduced pressure to prepare a water-soluble polyurethane resin (A1) having a solid content of 37% by mass. The glass transition point temperature of the obtained polyurethane resin was -30 ° C.

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

38.41 parts by weight of isophorone diisocyanate, 6.95 parts by weight of dimethylolpropanoic acid, 158.99 parts by weight of polyhexamethylene carbonate diol having a number average molecular weight of 2000, 0.03 parts by weight of dibutyl tin dilaurate, and 84.00 parts by weight of acetone as a solvent A water-soluble polyurethane resin (A2) was prepared in the same manner as the polymerization of A1.

(Polymerization of block polyisocyanate-based crosslinking agent)

100 parts by mass of a polyisocyanate compound (Asahi Kasei Chemicals, Duranate TPA) having an isocyanurate structure using hexamethylene diisocyanate as a raw material in a flask equipped with a stirrer, thermometer, and reflux cooling tube, propylene glycol monomethyl ether 55 parts by mass of acetate and 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) were added, and maintained at 70 ° C for 4 hours under a nitrogen atmosphere. Thereafter, the temperature of the reaction solution was lowered to 50 ° C, and 47 parts by mass of methyl ethyl ketooxime was added dropwise. The infrared spectrum of the reaction solution was measured to confirm that the absorption of the isocyanate group was lost, and a blocked polyisocyanate aqueous dispersion (Cx1) having a solid content of 40% by mass was obtained.

(Polymerization of oxazoline-based crosslinking agent)

A mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropanol as an aqueous medium in a flask equipped with a thermometer, nitrogen gas introduction tube, reflux cooler, dropping lot and stirrer, and polymerization initiator (2,2'-azobis (2 -Amidinopropane) / dihydrochloride) 4 parts by mass was added. On the other hand, in the dropping lot, 16 parts by mass of 2-isopropenyl-2-oxazoline as a polymerizable unsaturated monomer having an oxazoline group, methoxypolyethylene glycol acrylate (average added mole number of ethylene glycol, 9 moles, Shinnakamura Chemical Co., Ltd.) Preparation) A mixture of 32 parts by mass and 32 parts by mass of methyl methacrylate were charged, and added dropwise over 1 hour at 70 ° C under a 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 with a solid content concentration of 40 mass%.

(Carbodiimide-based crosslinking agent polymerization)

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

(Epoxy clock crosslinking agent)

As the epoxy-based 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 was used (melamine-based crosslinking agent (Cx5)).

(Zirconia particles)

With reference to Example 8 of Japanese Patent Application Laid-Open No. 2008-290896, it was carried out as follows.

To a 3 liter glass container, 2283.6 g of pure water and 403.4 g of oxalic acid dihydrate were added, and heated at 40 ° C to prepare a 10.72% by mass aqueous oxalic acid solution. While stirring this aqueous solution, 495.8 g of zirconium oxycarbonate powder (ZrOCO ₃ , produced by AMR International Corp., converted to ZrO ₂ and containing 39.76% by mass) was slowly added and mixed for 30 minutes, followed by mixing at 90 ° C. for 30 minutes. Heating was performed. Subsequently, 1747.2 g of a 25.0 mass% tetramethylammonium hydroxide aqueous solution (manufactured by Tama Chemical Industries, Ltd.) was slowly added over 1 hour. At this time, the mixed solution was in a slurry form and contained 4.0% by mass in terms of ZrO ₂ . This slurry was transferred to a stainless steel autoclave container, and subjected to hydrothermal treatment for 5 hours at 145 ° C. The product after this hydrothermal treatment was completely free from sintered water and completely solvated. The obtained sol contained 4.0 mass% as ZrO ₂ , and the average particle diameter by pH 6.8 and dynamic light scattering was 19 nm. 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 the agglomerated particles of the ZrO ₂ primary particles around 7 nm were observed. 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 ultrapure water was slowly added thereto, and the ZrO ₂ concentration was 13.1 mass%, pH 4.9, and ZrO ₂ concentration 13.1. 953 g of a zirconia sol having a transmittance of 76% at mass% was obtained.

To the 300 g zirconia sol having a ZrO ₂ concentration of 13.1 mass% obtained by the above washing and concentration, 3.93 g of a 20 mass% aqueous citric acid solution and 11.0 g of a 25 mass% tetramethylammonium hydroxide aqueous solution were added, followed by further concentration by ultrafiltration. As a result, 129 g of a high concentration of 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 dynamic light scattering. Moreover, this zirconia sol was free of sediment and was stable for more than 1 month under the condition of 50 ° C.

Further, referring to Example 2 of Japanese Patent Application Publication No. 2008-290896, Cpz2 having an average particle diameter of 32 nm and Cpz3 having an average particle diameter of 48 nm were obtained with reference to Example 1.

(Titania particles)

With reference to Example 1 of Japanese Patent Application Laid-open No. 2011-132484, it was 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 ammonia water containing 15 mass% of ammonia (manufactured by Ubekosan Co., Ltd.) , A white slurry solution having a pH of 9.5 was prepared. Subsequently, after filtering this slurry, it wash | cleaned with pure water and obtained 9.87 kg of hydrous titanate cake whose solid content is 10 mass%. Next, after adding 11.28 kg of hydrogen peroxide water (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 20.00 kg of pure water to the cake, containing 35 mass% of hydrogen peroxide, heated to 80 ° C under stirring for 1 hour, Further, 57.52 kg of pure water was added, and 98.67 kg of an aqueous solution of titanic acid peroxide containing titanic acid per 1 mass% based on TiO ₂ conversion was obtained. The aqueous solution of titanic acid peroxide was transparent yellow-brown and had a pH of 8.5.

Subsequently, 4.70 kg of a cation exchange resin (manufactured by Mitsubishi Chemical Co., Ltd.) was mixed with 98.67 kg of the aqueous solution of titanic acid titanate, and potassium stannate (manufactured by Showa Chemical Co., Ltd.) was included in an amount of 1% by mass in terms of SnO _2. 12.33 kg of an aqueous potassium tartrate solution was slowly added under stirring. Next, after removing the cation exchange resin containing potassium ion, etc., it was put into an autoclave (made by Daitsu Garas Kogyo Co., Ltd., 120 L) and heated at a temperature of 165 ° C. for 18 hours.

Next, after the obtained mixed aqueous solution was cooled to room temperature, it was concentrated with an ultrafiltration membrane apparatus (ACV-3010, manufactured by Asahi Kasei Co., Ltd.), and the titanium-based fine particles having a solid content of 10% by mass (hereinafter referred to as "P-1") ”), 9.90 kg of water dispersion sol (Cpt1) was obtained. The solids contained in the sol thus obtained were measured by the above method, and were titanium-based fine particles (primary particles) made of a composite oxide containing titanium and tin having a rutile crystal structure. Moreover, when content of the metal component contained in these titanium microparticles was measured, it was 87.2 mass% of TiO ₂ , 11.0 mass% of SnO ₂ , and 1.8 mass% of K ₂ O on the basis of oxide conversion of each metal component. Moreover, the pH of this mixed aqueous solution was 10.0. In addition, the water-dissolving sol containing the titanium-based fine particles is a transparent milky white, and the average particle diameter of the titanium-based fine particles contained in the water-dissolving sol is 35 nm, and further, a 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 fine particles could be regarded as 2.42.

Further, referring to Example 2 of Japanese Patent Application Laid-Open No. 2011-132484, Cpt2 having an average particle diameter of 32 nm and Cpt3 having an average particle diameter of 42 nm were obtained with reference to Example 4.

(Zirconia / Titania mixed particles)

By mixing the zirconia particles (Cpz1) and titania particles (Cpt1) obtained in the above 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.

Moreover, Cp2 (average particle diameter 32 nm) was obtained from Cpz2 and Cpt2, and Cp3 (average particle diameter 46 nm) was obtained from Cpz3 and Cpt3.

(Ceria particles)

With reference to Japanese Patent Application Laid-Open No. 2011-132107, experiments were conducted as follows.

216 g of cerium (III) chloride heptahydrate was added to 10 L of distilled water, stirred, and dissolved. Further, while stirring was continued, the temperature was raised to 93 ° C, and the total amount of 5.6 kg of a 1.0% sodium hydroxide aqueous solution was added at once. Further, after stirring at 93 ° C for 6 hours, cooling to 25 ° C to obtain white precipitate.

The precipitate was separated by a centrifuge, 15 L of distilled water was added to the obtained precipitate, stirred and redispersed, and the precipitate was separated by a centrifuge. This operation was performed three times in total to wash the precipitate.

Distilled water was added to the obtained precipitate, the pH was adjusted to 9.2, and 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 dynamic light scattering was 34 nm.

(Formation of hard coat layer)

A coating liquid for forming a hard coat layer having the following composition was applied to a surface opposite to the surface of the polyester film prepared in the Examples described below, which adheres to the polarizer, using a # 10 wire bar, and dried at 70 ° C. for 1 minute. , Removed the solvent. Subsequently, a high-pressure mercury lamp was applied to the film coated with the hard coat layer, and ultraviolet rays of 300 mJ / cm ² were irradiated to obtain a polarizer protective film having a hard coat layer having a thickness of 5 μm.

· Coating solution for hard coat layer formation

Methyl ethyl ketone 65.00 mass%

Dipentaerythritol hexaacrylate 27.20% by mass

(A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd.)

Polyethylene diacrylate 6.80% by mass

(A-400 manufactured by Shin-Nakamura Chemical Co., Ltd.)

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

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

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

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

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

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

(1) Adjusting the coating liquid of the 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-based 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 substantially free of particles were subjected to 6 at 135 ° C. under reduced pressure of 133 Pa. Time to dry. Then, it was supplied to an extruder, melt-extruded in a sheet form at about 280 ° C, and rapidly cooled and solidified on a rotary cooling metal roll maintained at a surface temperature of 20 ° C to obtain an unstretched PET sheet.

The 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 in a roll group with a main speed difference to obtain a uniaxially stretched PET film.

Subsequently, after apply | coating the said coating liquid to one side of a PET film by roll coat method, it dried at 80 degreeC for 15 second. Further, the coating amount after drying after the final stretching was adjusted to be 0.12 g / m ² . Subsequently, with a tenter, the film was stretched 4.0 times in the width direction at 150 ° C, and the length in the width direction of the film was fixed, heated at 230 ° C for 0.5 seconds, and further relaxed at 3% in the width direction at 230 ° C for 10 seconds. By performing this, an easily adhesive polyester film for optics having a thickness of 38 µm was obtained. The polyurethane resin component, the polyester resin component, and other components in the coating layer are 20 mass%, 30 mass%, and 50 mass%, respectively, as shown in Table 2.

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

The easily-adhesive polyester film was obtained in the same manner as in Example 1 except that the crosslinking agent of the coating solution 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 the particle | grains of coating liquid and the composition of each component in a coating layer as Table 2.

(Examples 13 to 15)

The easily-adhesive polyester film was obtained like Example 1 except having changed the film thickness of the coating layer to Table 2.

(Examples 16 and 17)

The easily-adhesive polyester film was obtained like Example 1 except having changed the amount of the particle B in a coating layer to Table 2.

(Examples 26 and 27)

The easily-adhesive polyester film was obtained like Example 1 except having changed the type of the copolymerized polyester resin component to Table 3.

(Example 28)

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

The results are shown in Tables 2 and 3. In addition, the plots on the triangular diagrams of the Examples and Comparative Examples are shown in Fig. 1.

[Table 2]

[Table 3]

(Static friction coefficient, kinetic friction coefficient (㎲, μd))

In addition, the friction coefficient of the polyester film obtained in Examples and Comparative Examples was measured using Tensilon (Toyo Baldwin, RTM-100) according to the JIS K7125-1999 plastic-film and sheet friction coefficient test method, which The film was also in the range of 0.35 to 0.5 as the static friction coefficient (㎲) and 0.45 to 0.6 as the kinetic friction coefficient (μd), and there was no problem in the rollability and handling properties.

Industrial availability

According to the present invention, it is excellent in low coherence, transparency, blocking resistance, adhesion to various functional layers, and slipperiness that can suppress rainbow stains, and can be suitably used 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: straight line through coordinates (10, 55, 35) and (10, 10, 80)
Q1: straight line through coordinates (10, 10, 80) and (70, 10, 20)
R1: straight line through coordinates (70, 10, 20) and (50, 40, 10)
S1: straight line through coordinates (45, 45, 10) and (10, 55, 35)
○: Plot of each example
□: Plot of each comparative example
Numerical values in the triangular diagram: numbers of each example or each comparative example

Claims (5)

Contents of the polyurethane resin component when at least one side of the polyester film has a coating layer containing a polyurethane resin having a polycarbonate skeleton and a polyester resin having a naphthalene skeleton, and the solid content of the coating layer is 100 mass% When (mass%) is shown in the triangular diagram with a and the content (mass%) of the polyester resin component having a naphthalene skeleton as b and the total amount (mass%) of components other than these as c, a, b, c A self-adhesive polyester film in an area 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%, c is 35 mass%, 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%, c is 80 mass%, 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%, c is 20 mass%, 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%, c is 10 mass%, a is 10 mass%, b is 55 mass%, and c is 35 mass%. The method of claim 1,
An easily adhesive polyester film in which the coating layer contains a crosslinking agent. The method of claim 1 or 2,
An easily adhesive polyester film in which the coating layer contains metal oxide particles (particle A) having a refractive index of 1.7 or more. The method according to any one of claims 1 to 3,
An easily adhesive polyester film in which the coating layer contains the lubricant particles (particles B). At least one selected from the group consisting of a hard coat layer, an anti-glare layer, an anti-glare anti-reflective layer, an anti-reflective layer and a low-reflective layer on the coating layer of the easily adhesive polyester film according to any one of claims 1 to 4. A laminated polyester film having a functional layer.

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