TWI795442B - Easy Adhesive Polyester Film - Google Patents

Abstract

The object of the present invention is to provide an easy-adhesive polyester film that can suppress rainbow spots, low interference, high level of adhesion to hard coats, etc., and anti-blocking properties required for various optical applications. , transparency, and high sliding properties, it is suitable for optical applications with excellent operability during production or in subsequent steps such as the production of polarizing plates for liquid crystal display devices.

The solution of the present invention is an easy-adhesive polyester film, which has a coating layer on at least one side of the polyester film, and the coating layer contains a polyurethane resin with a polycarbonate skeleton, a naphthalene skeleton For polyester resin, when the total solid content of the coating layer is 100% by mass, the content of the polyurethane resin component is regarded as a, the content of the polyester resin component having a naphthalene skeleton is regarded as b, and other than these The total amount of the components in is regarded as c, and when expressed as a triangular diagram, a, b, and c are in the area surrounded by 4 specific straight lines.

Description

Easy Adhesive Polyester Film

The present invention relates to an easy-adhesive polyester film which can ensure low interference which can eliminate the problem of iridescent spots, and which is excellent in adhesion, blocking resistance, and transparency to various functional layers. More specifically, it relates to an easily-adhesive polyester film applicable even to high-definition optical applications.

A hard-coated film laminated with a transparent hard-coat layer is used on the front of displays such as touch panels, computers, televisions, liquid crystal display devices, and decorative materials. Also, as the transparent plastic film of the substrate, a transparent polyester film is generally used. In order to improve the adhesion between the polyester film of the substrate and the hard coat layer, a coating layer with easy adhesion is provided as one of these intermediate layers. There are many situations.

In the aforementioned hard coat film, durability against temperature, humidity, and light, transparency, chemical resistance, scratch resistance, and antifouling properties are required. Also, since it is often used on the surface of displays and decoration materials, etc., visibility and design properties are required. Therefore, in order to suppress glare or iridescent color caused by reflected light when viewed from any angle, it is generally carried out to provide a multilayer structure in which high refractive index layers and low refractive index layers are alternately laminated on the top of the hard coat layer. anti-reflective layer.

However, for applications such as displays and decorative materials, larger screen size (larger area) and higher definition have been required in recent years, and correspondingly, the level of suppression of iridescent colors (interference spots) under fluorescent lamps has been particularly required. system gradually becomes higher. In addition, the three-wavelength type of fluorescent lamps has gradually become the mainstream for the reproducibility of daylight color, and interference spots are more likely to occur. Furthermore, the demand for cost reduction through the simplification of the anti-reflection layer is gradually increasing. Therefore, even if it is only a hard coat film without an antireflection layer, it is required to suppress interference spots as much as possible.

Furthermore, due to the development of mobile technology, the use of mobile devices such as mobile phones, car navigation or e-books in outdoor areas is expanding. Also, from the point of view of thinning, almost all of the mobile devices mentioned above are liquid crystal panel displays. In such fields, for example, in a mobile phone equipped with a touch panel, as a hard-coated film for display surface protection, interference fringes caused by reflected light on both interfaces contacting the coated surface, or on graphic sheets In applications where designability is applied to the back of the hard-coated film, the disadvantage of visibility due to interference fringes is becoming more pronounced.

It is generally believed that the iridescent color (interference spots) of the hard-coated film is due to the difference in the refractive index of the base polyester film (such as 1.62~1.65) and the refractive index of the hard-coated layer made of acrylic resin (such as 1.49) big and happen. In order to reduce the refractive index difference between laminated layers and prevent the occurrence of interference spots, it is proposed to set a coating layer with a relatively high refractive index on the polyester film of the substrate to reduce the refractive index difference between the polyester film and the coating layer, and the coating layer The method of refractive index difference with the hard coating.

Conventionally, in the field of easy-adhesive films for optics, 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 and a method of increasing the refractive index of the resin of the coating layer are known. wait. In particular, polyester resins using naphthalene dicarboxylic acid as a copolymerization component have excellent adhesion to base polyester films, and have been proposed as suitable examples (for example, refer to Patent Document 1). . However, in general, polyester resins with a high refractive index have a problem of poor adhesion due to a high glass transition temperature, lack of flexibility of the resin, or poor blocking resistance when the amount of polyester resin is increased. Condition. On the other hand, there is a proposal to use a polyurethane resin having a polycarbonate component as a resin having excellent flexibility and high adhesion (see, for example, Patent Document 2). Polyurethane resins having polycarbonate components are combined, but if the polyurethane components are increased, there are problems of low interference and poor transparency. In this way, there has been no easy-adhesive polyester film that can cope with the high level of low-interference properties in recent years and have all of the adhesion to the hard coat layer, anti-blocking property, and transparency in a highly balanced manner. .

prior art literature patent documents

Patent Document 1 Japanese Patent Laid-Open No. 2011-246663

Patent Document 2 Japanese Patent Application Laid-Open No. 2011-168053

The present invention has been accomplished against the background of such conventional technical problems. That is, the object of the present invention is to provide an easily adhesive polyester film which can suppress rainbow spots, low interference, high level of adhesion to hard coats, etc., and anti-sticking properties required in various optical applications. It is excellent in connectivity and transparency, and has high sliding properties, so it is suitable for optical applications with excellent operability in subsequent steps such as manufacturing or polarizing plate manufacturing steps of liquid crystal display devices.

That is, the present invention includes the following configurations.

1. An easily bondable polyester film, which has a coating layer on at least one side of the polyester film, and the coating layer contains a polyurethane resin with a polycarbonate skeleton, a polyester resin with a naphthalene skeleton, When the total solid content of the coating layer is 100% by mass, the content (mass %) of the polyurethane resin component is regarded as a, and the content (mass %) of the polyester resin component having a naphthalene skeleton is regarded as b, When the total amount (mass %) of other components is regarded as c and expressed in a triangular diagram, a, b, and c are within the area surrounded by four straight lines: straight line P1, straight line Q1, straight line R1, and straight line S1 .

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

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

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

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

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

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

3. The easily-adhesive polyester film according to the above-mentioned 1 or 2, wherein the coating layer contains metal oxide particles (particles A) having a refractive index of 1.7 or higher.

4. The easily-adhesive polyester film according to any one of the above 1 to 3, wherein the coating layer contains lubricant particles (particles B).

5. A laminated polyester film, which is on the coating layer of the easily bondable polyester film as described in any one of the above-mentioned 1 to 4, and has a coating layer selected from a hard coat layer, an anti-glare layer, an anti-glare anti-glare One or more functional layers in the group consisting of reflective layer, antireflective layer and low reflective layer.

According to the present invention, it is possible to provide an easily bondable polyester film which is capable of suppressing iridescent spots, has low interference properties, transparency, anti-blocking properties, adhesion to various functional layers, and excellent sliding properties, and is suitable for use in optical use.

P1‧‧‧The line passing through the coordinates (10,55,35) and (10,10,80)

Q1‧‧‧The line passing through the coordinates (10,10,80) and (70,10,20)

R1‧‧‧The line passing through the coordinates (70,10,20) and (50,40,10)

S1‧‧‧The line passing through the coordinates (45,45,10) and (10,55,35)

○‧‧‧Plotting of each embodiment

□‧‧‧Plotting of each comparative example

Numerical values in the triangle graph‧‧‧number of each embodiment or each comparative example

Fig. 1 is a triangular graph showing the preferred range of the easily-adhesive polyester film of the present invention.

Form of implementing the invention (Polyester film)

The polyester film used as the substrate in the present invention is a film made of polyester resin, preferably mainly polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate A polyester film comprising at least one of diester and polyethylene naphthalate as a constituent. In addition, a film composed of a copolymerized polyester obtained by copolymerizing the third component monomer with the aforementioned polyester may also be used. Among these polyester films, polyethylene terephthalate film is the best in terms of the balance between physical properties and cost.

Also, the aforementioned polyester film can be single-layered or multi-layered. In addition, as long as the effect of the present invention is achieved, in each of these layers, the polyester resin may contain various additives as necessary. Examples of additives include antioxidants, light stabilizers, antigelling agents, organic wetting agents, antistatic agents, ultraviolet absorbers, surfactants, and the like.

(coating layer)

The easily-adhesive polyester film of the present invention is one in which an easily-adhesive coating layer is laminated on the base film made of polyester as described above.

In the coating layer in the present invention, when the total amount (solid content) of the coating layer is 100% by mass, the content (mass %) of the polyurethane resin component having a polycarbonate skeleton is regarded as a, and the content (mass %) of the polyurethane resin component having a naphthalene skeleton is The content (mass %) of the polyester resin component is regarded as b, and the total amount (mass %) of other components is regarded as c, and when expressed in a triangular graph, a, b, and c are preferably on the straight line P1, Within the range of the area surrounded by the four straight lines of straight line Q1, straight line R1, and straight line S1.

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

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

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

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

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

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

Using the triangular chart shown in Figure 1, the above preferred ranges are briefly explained. On the three sides of the triangular graph, 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 are respectively displayed The axis of c (mass %). Here, if the internal coordinates of the triangle diagram are written in the order of (a, b, c), then five coordinates (10, 55, 35), (10, 10, 80), ( 70,10,20), (50,40,10) and (45,45,10). Also, the straight line P1 passing through (10,55,35) and (10,10,80), the straight line Q1 passing through (10,10,80) and (70,10,20), and the straight line P1 passing through (70,10,20) are displayed. ) and the straight line R1 of (50,40,10) and the 4 straight lines passing through the straight line S1 of (45,45,10) and (10,55,35). It has a well-balanced range of low interference (improvement of interference fringes), adhesion, anti-blocking, and transparency.

Furthermore, more preferable ranges of each straight line are described below.

Instead of the straight line P1, it is preferable to use the straight line P2 (the point where a is 15 mass%, b is 55 mass%, and c is 30 mass% and a is 15 mass%, b is 10 mass%, and c is 75 mass%. point line).

Instead of the straight line Q1, it is preferable to use the straight line Q2 (through the point where a is 10 mass%, b is 20 mass%, and c is 70 mass%, and a is 70 mass%, b is 10 mass%, and c is 20 mass%. point), more preferably a straight line Q3 (through the point where a is 20% by mass, b is 20% by mass, and c is 60% by mass and a is 70% by mass, b is 10% by mass, and c is 20% by mass point of the straight line).

Instead of the straight line R1, it is preferable to use the straight line R2 (through the point where a is 65% by mass, b is 10% by mass, and c is 25% by mass and the point where a is 45% by mass, b is 40% by mass, and c is 15% by mass point), more preferably a straight line R3 (through the point where a is 60% by mass, b is 10% by mass, and c is 30% by mass and a is 40% by mass, b is 40% by mass, and c is 20% by mass point of the straight line).

Instead of the straight line S1, it is preferable to use the straight line S2 (through the point where a is 50 mass%, b is 40 mass%, and c is 10 mass%, and a is 10 mass%, b is 50 mass%, and c is 40 mass%. point), more preferably a straight line S3 (through the point where a is 52% by mass, b is 38% by mass, and c is 10% by mass and a is 10% by mass, b is 48% by mass, and c is 42% by mass The straight line at the point), particularly preferably using S4 (through the point where a is 55% by mass, b is 35% by mass, and c is 10% by mass and a is 10% by mass, b is 45% by mass, and c is 45% by mass point of the straight line).

The lower limit of the content a of the polyurethane resin component having a polycarbonate skeleton is preferably 10% by mass, more preferably 13% by mass, and especially preferably 15% by mass. When the content a of the polyurethane resin component having a polycarbonate skeleton is 10% by mass or more, it is preferable to satisfy the adhesiveness without impairing transparency.

The upper limit of the content a of the polyurethane resin component having a polycarbonate skeleton is preferably 70% by mass, more preferably 60% by mass, particularly preferably 50% by mass, and particularly preferably 40% by mass. When the content a of the polyurethane resin component having a polycarbonate skeleton is 70% by mass or less, it is preferable because the refractive index is kept high and low interference is obtained.

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 particularly preferably 20% by mass. When 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 the content b of the polyester resin component having a naphthalene skeleton is preferably 55% by mass, more preferably 50% by mass, particularly preferably 48% by mass, particularly preferably 45% by mass. When content b of the polyester resin component which has a naphthalene skeleton is 55 mass % or less, antiblocking property is exhibited, and it is preferable.

The lower limit of the content c of other components is preferably 10% by mass, more preferably 20% by mass, particularly preferably 25% by mass, and most preferably 30% by mass. When content c of other components is 10 mass % or more, it contains the component which raises the refractive index of a coating layer, and it is preferable to improve low interference. Also, as a result, it is preferable to prevent blocking because the content a of the polyurethane resin having a polycarbonate skeleton is not too much.

The upper limit of the content c of other components is preferably 80% by mass, more preferably 70% by mass, particularly preferably 60% by mass, and most preferably 55% by mass. If the content c of the other components is 80% by mass or less, it is easy to obtain a balance between 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 maintain a tight balance. Coatability, easy to achieve a balance between anti-adhesion and refractive index (low interference).

(polyurethane resin with polycarbonate skeleton)

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

Examples of the aliphatic polycarbonate polyol include aliphatic polycarbonate diol, aliphatic polycarbonate triol, and the like, and aliphatic polycarbonate diol can be suitably used. Examples of the aliphatic polycarbonate diol that is a constituent of the urethane resin of the present invention include 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, One or more diols such as diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol with, for example, dimethyl carbonate, diphenyl carbonate, carbonic acid Aliphatic polycarbonate diol obtained by reacting carbonates such as ethylidene and phosgene.

Polyurethane resin having a polycarbonate skeleton is measured by infrared spectroscopy. Absorbance (A1460) near 1460 cm ^-1 from the aliphatic polycarbonate component and 1530 cm from the urethane component The ratio (A1460/A1530) of the absorbance (A1530) around ^-1 is preferably 0.40~2.30.

When the said ratio (A1460/A1530) is 0.40 or more, since there are not too many hard urethane components, it is preferable not to reduce the stress relaxation of a coating layer, and not to fall in heat-and-moisture resistance. In addition, when the above-mentioned ratio (A1460/A1530) is 2.30 or less, the aliphatic component of the soft aliphatic polycarbonate is not too much, the solvent resistance of the coating layer is maintained, and the moisture and heat resistance is not likely to be lowered, so it is preferable.

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

Examples of the polyisocyanate that is a constituent of the urethane resin of the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and 4,4-bicyclic diisocyanate. Hexylmethane diisocyanate, alicyclic diisocyanates such as 1,3-bis(isocyanatemethyl)cyclohexane, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate Aliphatic diisocyanates such as these, or polyisocyanates in which trimethylolpropane or the like is added in advance to these compounds singly or in plural. The above-mentioned polyisocyanates have no yellowing problem, and are more suitable for optical applications requiring high transparency. In addition, such a polyisocyanate-based coating film is not too tough, and it is preferable that stress due to shrinkage and swelling of photocurable resins and the like can be relieved and adhesion can be maintained.

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

啉、N-乙基

啉等之N-烷基

啉類、N-二甲基乙醇胺、N-二乙基乙醇胺等之N-二烷基烷醇胺類。此等係可單獨使用，也可併用2種以上。 In order to introduce a carboxylic acid (salt) group into a urethane resin, for example, as a polyol component, a polyol compound having a carboxylic acid group such as dimethylol propionic acid or dimethylol butyric acid is introduced as a copolymer Components, neutralized by salt formers. Specific examples of salt forming agents include trialkylamines such as cyanide, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, and tri-n-butylamine, N-methyl

phylloline, N-ethyl

N-Alkyl

N-dialkylalkanolamines such as morphines, N-dimethylethanolamine, N-diethylethanolamine, etc. These systems may be used alone or in combination of two or more.

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 that the amine When the total polyol component of the urethane resin is taken as 100 mol%, it is preferably 3-60 mol%, more preferably 5-40 mol%. When the molar ratio of the aforementioned composition is 3 mol % or more, the water dispersibility is good and it is preferable. Also, when the molar ratio of the aforementioned composition is 60 mol % or less, it is preferable to maintain water resistance and heat and humidity resistance.

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

(polyester resin with naphthalene skeleton)

As the acid component of the polyester resin contained in the coating layer, by including the component derived from naphthalene dicarboxylic acid, the refractive index increases, and the iridescent color under the fluorescent lamp can be easily controlled. In addition, heat-and-moisture resistance can be improved.

As such naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid is preferable. The ratio of the above-mentioned naphthalene dicarboxylic acid in all the dicarboxylic acid components constituting the polyester resin is preferably at least 20 mol%, more preferably at least 30 mol%, particularly preferably at least 50 mol%, even more preferably at least 50 mol%. More than 60 mole%.

In addition, as long as the effect of the present invention is achieved, as the acid component in the polyester resin, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 1,4- Cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, dimer acid, 5-sodiumsulfoisophthalic acid, 4-sodiosulfonaphthalene-2,7-dicarboxylic acid, adipic acid , Azelaic acid, sebacic acid, etc. When these are copolymerized, naphthalene dicarboxylic acid is also contained in terms of heat and humidity resistance and high refractivity, and the aromatic dicarboxylic acid component is preferably at least 70 mol%, more preferably at least 80 mol%. In particular, when emphasis is placed on heat and humidity resistance and high refractivity, the aromatic dicarboxylic acid component is preferably at least 90 mol%, more preferably at least 95 mol%, and most preferably 100%.

As long as the effect of the present invention is achieved, as the diol component in the polyester resin, ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,6- Hexylene glycol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanedimethanol, xylene glycol, ethylene oxide adduct of bisphenol A, etc.

In addition, when the content of the polyurethane resin having a polycarbonate skeleton in the coating layer is reduced, the flexibility of the coating film will deteriorate, and there is a possibility that the coating layer will be cut or particles will fall off during post-processing. . In such a case, what contains the dicarboxylic-acid component represented by following formula (1) and/or the diol component represented by following formula (2) in polyester resin is one of preferable aspects.

(1) HOOC-(CH ₂ ) _n -COOH (where n is an integer of 4≦n≦10)

(2) HO-(CH ₂ ) _n -OH (where n is an integer of 4≦n≦10)

In this way, by including the acid component and/or the diol component having a carbon component having a specific length, the polyester resin is given flexibility, even if it is a relatively large particle, it is easy to hold, and the reduction or reduction of the coating layer can be suppressed. Particles fall off.

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

Polyester resins can use water or water-miscible organic solvents (for example, aqueous solutions containing less than 50% by mass of alcohols, alkyl celuso, ketones, ethers) or organic solvents (for example, toluene, ethyl acetate Esters, etc.) are dissolved or dispersed.

When using a polyester resin as a water-based coating solution, a water-soluble or water-dispersible polyester resin is used, but for such water-solubility or water dispersion, it is preferable to copolymerize a compound containing a sulfonate group or a compound containing a carboxylic acid. base compound.

From the aspects of film strength and ease of water dispersion, the number average molecular weight of the polyester resin is preferably 5,000-40,000, more preferably 10,000-30,000, and most preferably 12,000-25,000.

In addition, the polyester resin system containing a naphthalene dicarboxylic acid component may be single, or may be a blend of 2 or more types. In the case of a blend of two or more types, the total of the polyester resin components is preferably the composition described above.

Examples of other components contained in the coating layer include binder resins other than polyurethane resins having a polycarbonate skeleton or polyester resins containing naphthalene dicarboxylic acid components, crosslinking agents, and lubricant particles. , metal oxide particles that increase the refractive index of the coating layer, surfactants, etc., but in the present invention, preferably include crosslinking agents, lubricant particles, and metal oxide particles that increase the refractive index of the coating layer. There are cases where the coating liquid contains a solvent and a surfactant, etc., but the mass of the solvent remaining after drying and hardening or the mass of the solid content of the surfactant is very small, and the amount of each component is calculated from the coating liquid. When making the composition, the mass of the residual solvent or the mass of the solid content of the surfactant may not necessarily be included in the mass of the solid content of the entire coating layer. The description of the composition of the examples is based on the aforementioned calculation.

唑啉系、碳二亞胺系等。於此等之中，從塗液的隨著時間經過安定性、高溫高濕處理下的密著性提高效果來看，較佳為三聚氰胺系、異氰酸酯系、

唑啉系、碳二亞胺系之交聯劑。又，為了促進交聯反應，視需要可適宜使用觸媒等。 In order to form a crosslinked structure in the coating layer, the coating layer may be formed containing a crosslinking agent. By containing a crosslinking agent, the adhesiveness under high temperature and high humidity can be further improved. Specific crosslinking agents include urea-based, epoxy-based, melamine-based, isocyanate-based,

Azoline series, carbodiimide series, etc. Among these, melamine-based, isocyanate-based, and

Azoline-based and carbodiimide-based cross-linking agents. Moreover, in order to promote a crosslinking reaction, a catalyst etc. can be used suitably as needed.

When the coating layer includes a crosslinking agent, the content of the crosslinking agent is preferably from 5% by mass to 50% by mass, more preferably from 10% by mass to 40% by mass, of the total solid content of the coating layer. If it is 10% by mass or more, the resin strength of the coating layer is maintained, and the adhesion under high temperature and high humidity is good. If it is 40% by mass or less, the resin flexibility of the coating layer is maintained, and the adhesion under normal temperature, high temperature and high humidity is maintained. It is more suitable for wearing.

In addition, it is preferable that the coating layer contains metal oxide particles (particles A) having a high refractive index of 1.7 or more. Examples of 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, etc.

The lower limit of the refractive index of the particles A is preferably 1.7, more preferably 1.75. The upper limit of the refractive index of the particles A is preferably 3.0, more preferably 2.7, and most preferably 2.5. By setting it as the said range, the balance of low interference property, transparency, adhesiveness, and anti-blocking property can be obtained favorable.

The composite oxide particles used as the particles A are preferably TiO ₂ /ZnO particles (zirconia/titania mixed particles). The so-called zirconia/titania mixed particles are particle groups in which zirconia and titania are dispersed in a single liquid separately and in an aggregated state without forming a complex, including both zirconia and titania. Of course, in the coating layer, the liquid component hardly evaporates in the drying step or hardening step. Since the coating layer contains such particles A, the balance between slipperiness and transparency is excellent, and high transparency and low interference can be ensured. The liquid system is preferably an aqueous liquid in order to easily form a coating layer by the so-called in-line coating method described later.

In the zirconia/titania mixed particles, other components other than zirconia/titania may also be included, which may be inorganic particles or organic particles, and are not particularly limited. Silica, titania (titania), zirconia ( zirconia), talc, kaolinite, and other metal oxides, calcium carbonate, calcium phosphate, barium sulfate, and other inorganic particles that are inert to polyester.

The average particle diameter of the particles A is preferably at least 5 nm, more preferably at least 10 nm, especially preferably at least 15 nm, and most preferably at least 20 nm. If the average particle diameter of the particle A is 5 nm or more, it is not easy to agglomerate and it is preferable.

The average particle diameter of the particles A is preferably not more than 200 nm, more preferably not more than 150 nm, especially preferably not more than 100 nm, particularly preferably not more than 60 nm. When the average particle diameter of the particles A is 200 nm or less, the transparency is good, which is preferable.

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

Particle B series can include (1) silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, aluminum oxide, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, satin Inorganic particles such as white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrated halloysite, magnesium carbonate, magnesium hydroxide, etc., (2) acrylic or methacrylic, vinyl chloride, vinyl acetate Ester, nylon, styrene/acrylic, styrene/butadiene, polystyrene/acrylic, polystyrene/isoprene, methyl methacrylate/butyl methacrylate, melamine series, polycarbonate series, urea series, epoxy series, urethane series, phenol series, diallyl phthalate series, polyester series, etc., but in order to impart moderate sliding properties For the coating layer, it is particularly preferable to use silica.

The average particle diameter of the particles B is preferably at least 200 nm, more preferably at least 250 nm, especially preferably at least 300 nm, and most preferably at least 350 nm. When the average particle diameter of the particle B is 200 nm or more, it is difficult to aggregate and the sliding property can be ensured, which is preferable.

The average particle diameter of the particles B is preferably not more than 2000 nm, more preferably not more than 1500 nm, especially preferably not more than 1000 nm, particularly preferably not more than 700 nm. When the average particle diameter of the particles B is 2000 nm or less, the transparency is maintained and the particles do not fall off, so it is preferable.

The surface treatment of the particles A and B can also be carried out. 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 the use of a coupling agent is preferred. As the coupling agent, an organoalkoxy metal compound (for example, a titanium coupling agent, a silane coupling agent) is preferably used. When the particle B is silica, the silane coupling treatment is particularly effective. The surface treatment agent for the particles B may be used for surface treatment before the layer coating liquid is prepared, or may be added as an additive to be contained in the layer when the layer coating liquid is prepared. Of course, particle A can also be used.

The content of the particles A in the coating layer is preferably at least 2% by mass, more preferably at least 3% by mass, particularly preferably at least 4% by mass, and particularly preferably at least 5% by mass. 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 kept high, and low interference is effectively obtained, which is preferable.

The particle A content in the coating layer is preferably at most 50% by mass, more preferably at most 40% by mass, especially preferably at most 30% by mass, and most preferably at most 20% by mass. When the particle A content in the coating layer is 50% by mass or less, it is preferable to maintain film-forming properties.

The particle B content in the coating layer is preferably at least 0.01% by mass, more preferably at least 0.05% by mass, and most preferably at least 0.1% by mass. When the particle B content in the coating layer is 0.01% by mass or more, it is preferable to maintain moderate slipperiness.

The particle B content in the coating layer is preferably at most 2% by mass, more preferably at most 1.5% by mass, and most preferably at most 1% by mass. When the particle B content in the coating layer is 2% by mass or less, the haze can be kept low, which is preferable in terms of transparency.

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

The film thickness of the coating layer is preferably at most 2 μm, more preferably at most 1 μm, especially preferably at most 0.8 μm, particularly preferably at most 0.5 μm. If the film thickness of the coating layer is 2 μm or less, there is no possibility of blocking, which is preferable.

In the coating layer, a surfactant may be contained for the purpose of improving the leveling property at the time of coating and degassing the coating liquid. The surfactant system may be any of cationic, anionic, nonionic, etc., but is preferably polysiloxane-based, acetylenic glycol-based or fluorine-based surfactants. These surfactants are preferably contained in the coating layer within a range that does not impair the iridescent color suppression effect or adhesiveness under fluorescent lamps.

In order to impart other performances to the coating layer, various additives may be contained within a range that does not impair the iridescent color suppression effect or adhesiveness under fluorescent lamps. Examples of the aforementioned additives include fluorescent dyes, fluorescent whitening agents, plasticizers, ultraviolet absorbers, pigment dispersants, foam suppressors, antifoamers, antiseptics, and the like.

As the coating method, any of the so-called in-line coating method in which the polyester base film is formed into a film, and the so-called off-line coating method in which the polyester base film is coated separately with a coater can be applied. Or, but the in-line coating method is more efficient and more suitable.

As the coating method, any well-known method can be used for coating the coating liquid on a polyethylene terephthalate (hereinafter, abbreviated as PET) film. For example, reverse roll coating method, gravure coating method, kiss coating method, die coating method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, dip coating method, curtain coating method, etc. coating method, etc. These methods can be applied alone or in combination.

In the present invention, as a method of forming a coating layer on a polyester film, a method of coating and drying a coating liquid containing a solvent, particles, and a resin on a polyester film is mentioned. Examples of the solvent include organic solvents such as toluene, water or a mixture of water and a water-soluble organic solvent, but water alone or a water-soluble organic solvent mixed with water is preferred from the viewpoint of environmental issues.

The solid content concentration of the coating solution also depends on the type of binder resin or the type of solvent, but is preferably 2% by mass or more, more preferably 4% by mass. The solid content concentration of the coating liquid is preferably at most 35% by mass, more preferably at most 15% by mass.

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

The surface roughness (Ra) of the coating layer is related to the sliding properties of the coating layer surface, etc., and is preferably at least 0.01 nm, more preferably at least 0.1 nm, especially preferably at least 0.2 nm, and most preferably at least 0.5 nm. On the other hand, the upper limit of the surface roughness (Ra) of the coating layer is preferably not more than 200 nm, more preferably not more than 100 nm, especially preferably not more than 80 nm, particularly preferably not more than 50 nm.

(Manufacture of optical adhesive polyester film)

The optically adhesive polyester film of the present invention can be produced according to a general method for producing polyester films. For example, polyester resin is melted, extruded into a sheet, and the shaped non-oriented polyester is stretched in the longitudinal direction by using the speed difference of the rollers at a temperature above the glass transition temperature, and then stretched in the transverse direction by a tenter. The method of middle extension and heat treatment.

The polyester film of the present invention can be a uniaxially stretched film or a biaxially stretched film, but when a biaxially stretched film is used as a protective film on the front of a liquid crystal panel, even if it is observed from directly above the film surface, it cannot be seen. There are iridescent spots, but when viewed from an oblique direction, due to the observation of iridescent spots, attention must be paid.

This phenomenon is due to the fact that the biaxially stretched film is composed of refractive index ellipsoids with different refractive indices in the traveling direction, width direction, and thickness direction. According to the light penetration direction inside the film, the in-plane hysteresis becomes zero ( The refractive index ellipsoid is regarded as a true circle) and exists in the direction. Therefore, when the liquid crystal display screen is observed from a specific direction in an oblique direction, a point where the in-plane retardation becomes zero may appear, and iridescent color irregularities may appear concentrically around this point. Furthermore, if the angle from directly above the film surface (normal direction) to the position where iridescent stains can be seen is θ, the angle θ becomes larger as the birefringence in the film surface increases. , and iridescent spots are difficult to see. Since the angle θ tends to be smaller in a biaxially stretched film, a uniaxially stretched film is more difficult to see iridescent spots and is preferable.

However, in a completely uniaxial (monoaxially symmetric) thin film, the mechanical strength in the direction perpendicular to the alignment direction is significantly lowered, which is not preferable. The present invention preferably has biaxiality (biaxial symmetry) in the range where iridescent stains do not substantially occur, or in the range where iridescent stains do not occur in the range of viewing angles required for liquid crystal display screens.

(Laminated polyester film)

In the present invention, the laminated polyester film that is mainly used for optical purposes is formed by setting a thermosetting resin made of electron beam or ultraviolet curable acrylic resin or siloxane on the coating layer of the easy-adhesive polyester film of the present invention. Hard coatings made of permanent resins, etc.

On the coating layer of the easily-adhesive polyester film of the present invention, it is also preferable to provide a functional layer. The so-called functional layer refers to anti-glare layer, anti-glare anti-reflection layer, anti-reflection layer, Functional layer such as low reflection layer and antistatic layer. Various well-known ones in the technical field can be used as the functional layer, and the type is not particularly limited. Hereinafter, each functional layer is demonstrated.

For example, in the formation of a hard coat layer, a well-known hard coat layer can be used, and it is not particularly limited, but it can be polymerized by drying, heat, chemical reaction, or irradiated with electron rays, radiation rays, and ultraviolet rays. / or reactive resin compounds. Examples of such curable resins include melamine-based, acrylic-based, polysiloxane-based, and polyvinyl alcohol-based curable resins, but light-curable resins are preferred for obtaining high surface hardness and optical design. Type of acrylic hardening resin. As such acrylic curable resins, polyfunctional (meth)acrylate monomers or acrylate oligomers can be used, and examples of acrylate oligomers include polyester acrylate, cyclo Oxygen acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, silicone acrylate, etc. The coating composition for forming the aforementioned optical functional layer can be obtained by mixing a reactive diluent, a photopolymerization initiator, a sensitizer, and the like with these acrylic curable resins.

The above-mentioned hard coat layer may also have an anti-glare function (anti-glare function) for scattering external light. The antiglare function (antiglare function) is obtained by forming irregularities on the surface of the hard coat layer. In this case, ideally, the haze of the film is preferably 0-50%, more preferably 0-40%, and most preferably 0-30%. Of course, 0% is ideal, 0.2% or more is fine, and 0.5% or more is okay.

Therefore, the application of the film of the present invention is mainly for the whole of optical films, and can be applied to optical films such as LCD, flat TV, CRT, etc. Base films for components, near-infrared absorption filters for components in front panels for plasma displays, transparent conductive films for touch panels or electroluminescence, etc.

As the above-mentioned acrylic resin hardened by electron rays or ultraviolet rays for forming the hard coat layer, more specifically, it has an acrylate-based functional group. For example, relatively low molecular weight polyester resins and polyether resins can be used. , acrylic resin, epoxy resin, urethane resin, alkyd resin, spirocetal resin, polybutadiene resin, polythiol polyene resin, polyol and other polyfunctional compounds (meth)acrylic acid Oligomers or prepolymers such as esters, and as reactive diluents, containing ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrole Monofunctional monomers and polyfunctional monomers such as pyridone, such as trimethylolpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethyl Glycol di(meth)acrylate, Neopentylthritol tri(meth)acrylate, Dineopentylthritol hexa(meth)acrylate, 1,6-Hexanediol di(meth)acrylate, Neopentyl glycol di(meth)acrylate and the like.

However, in the case of electron beam or ultraviolet curable resins, acetophenones, diphenyl ketones, Michelle benzoyl benzoate, α-Amyloxime ester, tetramethylsulfurammonosulfide, thioxanthones, or as a photosensitizer, can be mixed with n-butylamine, triethylamine, tri-n-butyl Phosphine etc. are used.

In addition, polysiloxane-based (siloxane-based) thermosetting resins can be produced by hydrolyzing and condensing two or more organosilane compounds alone or in combination under an acid or alkali catalyst. In particular, in the case of low reflection, it is preferable to mix one or more fluorosilane compounds for hydrolysis and condensation reaction in order to improve low refractive index properties, stain resistance, and the like.

(manufacture of laminated polyester film)

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

On the coating layer of the aforementioned easy-adhesive polyester film, the aforementioned electron beam or ultraviolet curable acrylic resin or siloxane-based thermosetting resin is coated. When coating layers are provided on both sides, it is applied to at least one coating layer. There is no particular need to dilute the coating liquid, but according to the viscosity, wettability, and film thickness of the coating liquid, there is no special problem even if it is diluted with an organic solvent. The coating layer is formed by coating the above-mentioned coating liquid on the above-mentioned film, drying it if necessary, and then hardening the coating layer by electron beam or ultraviolet irradiation and heating in accordance with the curing conditions of the coating liquid to form a hard coat layer.

In the present invention, the thickness of the hard coat layer is preferably 1-15 μm. When the thickness of the hard coat layer is 1 µm or more, the effects of chemical resistance, scratch resistance, and antifouling properties as the hard coat layer can be efficiently exhibited, and it is preferable. On the other hand, when the thickness is 15 μm or less, the flexibility of the hard coat layer is maintained and there is no possibility of cracks, etc., which is preferable.

As scratch resistance, when the coated surface is abraded with a black backing paper, it is preferable that scratches are not conspicuous visually. If the scratches are not conspicuous in the above evaluation, it is less likely to be damaged when passing through the guide rollers, which is preferable from the viewpoint of workability and the like.

The lower limit of the coefficient of static friction (μs) is preferably 0.3. If it is 0.3 or more, there will be no slippage problem. In the manufacturing process, it is easy to roll up with a hard chrome-plated roller to maintain operability and anti-blocking properties. The upper limit of the coefficient of static friction (μs) is preferably 0.5, and when it is 0.5 or less, it is preferable that there is no possibility of scratches being formed on the film that is the surface to be in contact with when being rolled up.

The lower limit of the coefficient of dynamic friction (μd) is preferably 0.4. If it is 0.4 or more, there will be no slippage problem. In the manufacturing process, it is easy to roll up with a hard chrome-plated roller to maintain operability and anti-blocking properties. The upper limit of the coefficient of dynamic friction (μd) is preferably 0.6, and when it is 0.6 or less, it is preferable that there is no possibility of scratches being caused on the film that is the surface to be in contact with when being rolled up.

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

The adhesiveness between the coating layer and the hard coat layer of easy adhesion is evaluated by the measurement method described later, and the lower limit is preferably 80%, and the upper limit is preferably 100%. If it is 80% or more, it can be said that the adhesiveness of a coating layer and a hard-coat layer is fully maintained.

Regarding the adhesion between the easily-adhesive layer and the hard coat layer under high-temperature and high-humidity conditions evaluated by the method described later, 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 adhesion between the easy-adhesive layer and the hard coat layer under high-temperature and high-humidity conditions is substantially satisfied, and the passability of the post-processing step is substantially satisfied. More preferably more than 50%.

The polyester film for polarizer protection formed with a hard coat layer preferably has no interference spots by the evaluation method described later, and as long as the interference spots are not seen by this evaluation method, the visibility of the liquid crystal imaging device will be reduced. Good and better.

The easily-adhesive polyester film of the present invention can be used in various applications, but is preferably used in the manufacturing process of polarizing plates used in liquid crystal display devices, and is particularly preferably used as a protective film for polarizers constituting polarizing plates. Generally, polarizers are mostly made of polyvinyl alcohol, and the easily bondable polyester film of the present invention is attached to the polarizer, and bonded with an adhesive made of polyvinyl alcohol or with a crosslinking agent added thereto if necessary. At that time, it is more preferable to use the coating layer of the easily-adhesive polyester film of the present invention not facing the side that is in contact with the polarizer, but facing the opposite side. On the surface of the easily-adhesive polyester film of the present invention that is bonded to the polarizer, it is preferable to laminate a polyester resin, a polyvinyl alcohol resin, and a cross-linking agent such as those described in International Publication No. 2012/105607. Easy to apply layers.

[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. Also, the evaluation method used in the present invention is as follows.

(1) Average particle size [Measuring method by scanning electron microscope]

The measurement of the average particle diameter of the said particle|grains can be performed by the following method. Particles are photographed with a scanning electron microscope (SEM), and the size of the smallest particle becomes 2~5mm, and the maximum diameter (distance between the two furthest points) of 300~500 particles is measured, and the average value is calculated. as the average particle size. The average particle diameter of the particle|grains which exist in the coating layer of this invention can be measured by this measuring method.

[Dynamic light scattering method]

The average particle diameter of the particles can also be obtained by the dynamic scattering method during the manufacture of particles or thin films. The sol was diluted with a dispersion medium, and the parameters of the dispersion medium were used, measured with a submicron particle analyzer N4 PLUS (manufactured by Beckman Coulter), and calculated by the cumulant method to obtain the average particle diameter. The average particle diameter of the particles in the sol is observed in the dynamic light scattering method, and when the particles are aggregated with each other, the average particle diameter of their aggregated particles is observed.

(2) Refractive index of particles

The measurement of the refractive index of the particles can be performed by the following method. After drying the inorganic particles at 150°C, immerse the mortar-pulverized powder in solvent 1 (the one with a lower refractive index than the particles), and then add a small amount of solvent 2 (the one with a higher refractive index than the particles) little by little. until the microparticles become roughly transparent. The refractive index of this liquid was measured using the Abbe refractometer (Abbe refractometer manufactured by ATAGO Co., Ltd.). The measurement system is carried out at 23°C, D line (wavelength 589nm). The above-mentioned solvent 1 and solvent 2 are selected to be compatible with each other. According to the refractive index, for example, 1,1,1,3,3,3-hexafluoro-2-propanol, 2-propanol, chloroform, tetrachloro Solvents such as carbon dioxide, toluene, glycerin, etc.

(3) Haze of easy-adhesive polyester film

The haze of the easily-adhesive polyester film was measured using a haze meter (Nippon Denshoku Corporation, NDH2000) in accordance with JIS K 7136:2000.

(4) Adhesion

On the easy-adhesive layer of the polyester film obtained in the Example, the hard-coat layer described in the formation item of the said hard-coat layer was formed. The adhesiveness between the hard coat layer and the substrate film was determined in accordance with the description in 8.5.1 of JIS-K5400-1990 for the polyester film for easy adhesion on which the hard coat layer was formed.

Specifically, using a cutter guide with a gap interval of 2 mm, the hard-coat layer was penetrated, and 100 grid-like cuts reaching the base film were made on the hard-coat surface. Next, a cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm wide) was attached to the grid-shaped cut surface, and it was completely adhered by rubbing it with an eraser. Then, tear off the cellophane adhesive tape vertically from the hard-coated surface of the hard-coated laminated polarizer protective film, and visually count the number of squares peeled off from the hard-coated surface of the hard-coated laminated polarizer protective film, from the following Calculate the adhesion between the hard coat layer and the substrate film. In addition, among the grids, the partially peeled ones were also counted as the peeled grids.

Adhesion (%)={1-(number of stripped squares/100)}×100

(5) Improvement of interference fringes (iridescent color)

A hard coat layer was formed on the easily-adhesive layer of the optically easily-adhesive polyester film obtained in each Example. An area of 10 cm (film width direction) x 15 cm (film length direction) was cut out from the optically easily-adhesive polyester film on which the hard coat layer was formed to prepare a sample film. A black glossy tape (manufactured by Nitto Denko Co., Ltd., vinyl tape No. 21; black) was attached to the surface opposite to the hard-coat layer surface of the obtained sample film. Make the hard-coated surface of the sample film the upper surface, and use a 3-wavelength type daylight white (National Palook, F.L 15EX-N 15W) as the light source, and visually observe the positional relationship of the strongest reflection from obliquely above (the distance from the light source is 40~60cm, 15~45° angle) for observation.

The results of visual observation were graded using the following criteria. In addition, observation was performed by 5 persons who were proficient in this evaluation, and the grade with the most was made into the evaluation grade. Assume that when two grades have the same number, the center divided into three grades is used. For example, when ◎ and ○ are 2 people each and △ is 1 person, use ○ when ◎ is 1 person and ○ and △ are 2 people each, and when ◎ and △ are 2 people each and ○ is 1 person Use ○.

◎: No iridescent color can be seen from all angles

○: Slightly iridescent colors are seen at certain angles

Δ: Iridescent color is slightly observed

×: Clear iridescent color observed

(6) Anti-adhesion

Two laminated films were stacked so that their coated surfaces faced each other, a load of 5 kg/cm ² was applied, and they were left to stand in an environment of 50° C. for 24 hours. The laminated films were peeled off, and the peeled state was judged by the following criteria.

◎: Can be peeled off gently

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

△: Peeling sound occurs, and the coating layer is partially transferred to the target surface

×: The two films are fixed and cannot be peeled off, or the base film will tear even if it can be peeled off

(7) Glass transition temperature

According to JIS K7121-1987, using a differential scanning calorimeter (manufactured by SEIKO Instruments, DSC6200), a 10 mg resin sample is heated at a rate of 20 °C/min in the temperature range of 25 to 300 °C, and the extrapolated glass obtained from the DSC curve is transferred. The onset temperature was taken as the glass transition temperature.

(8) Number average molecular weight

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

(9) Resin composition

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

(polymerization of polyester resin)

Polymerization of Copolymerized Polyester Resin (B1)~(B3) for Coating Layer

In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux cooler, add 342.0 parts by mass of dimethyl 2,6-naphthalene dicarboxylate, 35.0 parts by mass of dimethyl terephthalate, 35.5 parts by mass 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, from 160 ° C to 220 It took 4 hours to carry out the transesterification reaction up to ℃. Furthermore, 60.7 parts by mass of sebacic acid was added to perform esterification reaction. Next, the temperature was raised to 255° C., and the reaction system was gradually decompressed, followed by a reaction under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolymerized polyester resin (B1). The obtained copolymerized polyester resin is light yellow and transparent.

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

Moreover, the raw material was changed, and the copolymerization polyester resin (B2) and (B3) of the composition described in Table 1 were obtained similarly.

(manufacture of polyester aqueous dispersion)

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

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

(Manufacture of Polyurethane Aqueous Dispersion)

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

Put 43.75 parts by mass of 4,4-diphenylmethane diisocyanate, 12.85 parts by mass of dimethylol Butyric acid, 153.41 parts by mass of polyhexamethylene carbonate diol with 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, stirred at 75°C under a nitrogen atmosphere After 3 hours, it was confirmed that the reaction solution reached the specified amine equivalent. Next, after cooling this reaction liquid to 40 degreeC, 8.77 mass parts of triethylamines were added, and the polyurethane prepolymer solution was obtained. Then, add 450 g of water to a reaction vessel equipped with a homodisperser capable of high-speed stirring, adjust the temperature to 25°C, and add the polyurethane prepolymer solution while stirring and mixing for 2000 min ⁻¹ to perform water dispersion . Then, a water-soluble polyurethane resin (A1) having a solid content of 37% by mass was prepared by removing a part of acetone and water under reduced pressure. The glass transition temperature of the obtained polyurethane resin was -30 degreeC.

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

In addition to being 38.41 parts by mass of isophorone diisocyanate, 6.95 parts by mass of dimethylol propionic acid, 158.99 parts by mass of polyhexamethylene carbonate diol with a number average molecular weight of 2000, and 0.03 parts by mass of dilaurel Except dibutyltin acid and 84.00 parts by mass of acetone as a solvent, a water-soluble polyurethane resin (A2) was prepared in the same manner as in the polymerization of A1.

(polymerization of blocked polyisocyanate-based crosslinking agent)

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

(

Polymerization of oxazoline crosslinking agent)

唑啉基的聚合性不飽和單體之2-異丙烯基-2-

唑啉、32質量份的甲氧基聚乙二醇丙烯酸酯(乙二醇的平均加成莫耳數‧9莫耳，新中村化學製)及32質量份的甲基丙烯酸甲酯之混合物，於氮氣環境下，在70℃經歷1小時滴下。滴下結束後，攪拌反應溶液9小時，冷卻而得到固體成分濃度40質量%之具有

唑啉基的水溶性樹脂(Cx2)。 In a flask equipped with a thermometer, a nitrogen inlet tube, a reflux cooler, a dropping funnel, and a stirrer, a mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropanol was added as an aqueous medium and 4 parts by mass of a polymerization initiator Agent (2,2'-azobis(2-carboxamidinopropane)‧dihydrochloride). On the other hand, in the dropping funnel, drop 16 parts by mass as

2-isopropenyl-2- of the oxazoline-based polymerizable unsaturated monomer

A mixture of oxazoline, 32 parts by mass of methoxypolyethylene glycol acrylate (average addition moles of ethylene glycol‧9 moles, manufactured by Shin-Nakamura Chemicals) and 32 parts by mass of methyl methacrylate, Under a nitrogen atmosphere, it was dropped at 70° C. for 1 hour. After dropping, the reaction solution was stirred for 9 hours, cooled to obtain a solid content concentration of 40% by mass.

Azoline-based water-soluble resin (Cx2).

(polymerization of carbodiimide crosslinking agent)

In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, add 168 parts by mass of hexamethylene diisocyanate and 220 parts by mass of polyethylene glycol monomethyl ether (M400, average molecular weight 400), and stir at 120°C for 1 hours, 26 parts by mass of 4,4'-dicyclohexylmethane diisocyanate and 3.8 parts by mass (2% by mass relative to all isocyanates) of 3-methyl-1- Phenyl-2-phosphene-1-oxide was further stirred at 185° C. for 5 hours under nitrogen flow. Measure the infrared spectrum of the reaction solution to confirm that the absorption at wavelength 2200~2300cm ^-1 disappears. It was left to cool to 60°C, and 567 parts by mass of ion-exchanged water was added to obtain a carbodiimide water-soluble resin (Cx3) having a solid content of 40% by mass.

(Epoxy crosslinking agent)

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

(melamine-based crosslinking agent)

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

(zirconia particles)

Referring to Example 8 of JP-A-2008-290896, it was carried out as follows.

2283.6 g of pure water and 403.4 g of oxalic acid dihydrate were poured into a 3-liter glass container, heated to 40° C., and a 10.72% by mass oxalic acid aqueous solution was prepared. While stirring this aqueous solution, 495.8 g of zirconyl carbonate powder (ZrOCO ₃ , manufactured by AMR International Corp., containing 39.76% by mass in terms of ZrO ₂ ) was gradually added, mixed for 30 minutes, and then heated at 90° C. for 30 minutes. . Next, 1747.2 g of 25.0% by mass tetramethylammonium hydroxide aqueous solution (manufactured by Tama Chemical Industry Co., Ltd.) was gradually added over 1 hour. At this point in time, the liquid mixture was in a slurry state and contained 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 has no undissolved gel but is completely solified. The obtained sol contained 4.0% by mass of ZrO ₂ , had a pH of 6.8, and had an average particle diameter of 19 nm according to the dynamic light scattering method. Also, the sol was adjusted to a ZrO ₂ concentration of 2.0% by mass with pure water, and the measured transmittance was 88%. The particles were observed by a transmission electron microscope, and it was found that they were almost aggregated particles of ZrO ₂ primary particles of about 7nm. 4000 g of zirconia sol with a _ZrO2 concentration of 4.0% by mass obtained by the above-mentioned hydrothermal treatment was washed and concentrated while gradually adding pure water using an ultrafiltration device to obtain a _ZrO2 concentration of 13.1% by mass and a pH of 4.9. , 953 g of zirconia sol with a transmittance of 76% when the concentration of ZrO ₂ is 13.1% by mass.

To 300 g of zirconia _sol with a ZrO concentration of 13.1 mass % obtained by the above washing and concentration, 3.93 g of 20 mass % citric acid aqueous solution and 11.0 g of 25 mass % tetramethylammonium hydroxide aqueous solution were added. As a result of concentrating with an ultrafiltration device, 129 g of a high-concentration zirconia sol (Cpz1) having a ZrO ₂ concentration of 30.5% by mass was obtained. The resulting high-concentration zirconia sol had a pH of 9.3 and an average particle diameter of 19 nm according to the dynamic light scattering method. Also, this zirconia sol has no sediment and is stable for more than one month at 50°C.

Furthermore, referring to Example 2 of JP-A-2008-290896, Cpz2 with an average particle diameter of 32 nm was obtained, and referring to Example 1, Cpz3 with an average particle diameter of 48 nm was obtained.

(titanium dioxide particles)

Referring to Example 1 of JP-A-2011-132484, it was carried out as follows.

Mix 12.09 kg of titanium tetrachloride aqueous solution containing 7.75% by mass of titanium tetrachloride (manufactured by Osaka Titanium Technology Co., Ltd.) on the basis of _TiO2 conversion and 4.69 kg of ammonia water containing 15% by mass of ammonia (Ube Industries ( stock)) to prepare a white slurry with a pH of 9.5. Next, this slurry was filtered and washed with pure water to obtain 9.87 kg of a hydrous titanic acid filter cake with a solid content of 10% by mass. Next, 11.28 kg of hydrogen peroxide containing 35% by mass hydrogen peroxide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 20.00 kg of pure water were added to this filter cake, and heated at 80° C. for 1 hour with stirring. , 57.52 kg of pure water was further added to obtain 98.67 kg of peroxytitanic acid aqueous solution containing 1% by mass of peroxytitanic acid in terms of TiO ₂ . This aqueous solution of peroxytitanic acid is transparent yellow-brown and has a pH of 8.5.

Next, 4.70 kg of cation exchange resin (manufactured by Mitsubishi Chemical Co., Ltd.) was mixed with 98.67 kg of the aforementioned peroxotitanic acid aqueous solution, and 12.33 kg of cation exchange resin containing 1% by mass in terms of SnO ₂ was gradually added thereto under stirring. Potassium stannate aqueous solution (manufactured by Showa Chemical Co., Ltd.). Subsequently, after separating the cation exchange resin into which potassium ions and the like had been absorbed, it was placed in an autoclave (manufactured by Pressure Glass Industry Co., Ltd., 120 L) and heated at a temperature of 165° C. for 18 hours.

Subsequently, after cooling the resulting mixed aqueous solution to room temperature, it was concentrated with an ultrafiltration membrane device (manufactured by Asahi Kasei Co., Ltd., ACV-3010) to obtain a titanium-based microparticle (hereinafter referred to as "P-1") water dispersion sol (Cpt1) 9.90kg. The solid matter contained in the thus-obtained sol was measured by the method described above, and it was found to be titanium-based fine particles (primary particles) composed of a composite oxide containing titanium and tin having a rutile crystal structure. Furthermore, the content of the metal components contained in the titanium-based fine particles was measured, and the results were 87.2% by mass of TiO ₂ , 11.0% by mass of SnO ₂ , and 1.8% by mass of K ₂ O on the basis of the oxide conversion of each metal component. In addition, the pH of this mixed aqueous solution was 10.0. Furthermore, the aforementioned water-dispersed sol containing titanium-based microparticles is transparent milky white, and the average particle diameter of the aforementioned titanium-based microparticles contained in this water-dispersed sol is 35 nm by the dynamic light scattering method, and furthermore, it has a particle size of 100 nm or more. The distribution frequency of coarse particles with a diameter of 0% is 0%. In addition, the refractive index of the obtained titanium-based fine particles can be regarded as 2.42.

Furthermore, referring to Example 2 of JP-A-2011-132484, Cpt2 having an average particle diameter of 32 nm was obtained, and referring to Example 4, Cpt3 having an average particle diameter of 42 nm was obtained.

(zirconia/titania mixed particles)

The zirconia particles (Cpz1) and titania particles (Cpt1) obtained above were mixed at a mass ratio of 75/25 to prepare zirconia/titania mixed particles with a solid content concentration of 13% by mass ((Cp1): average particle diameter 23nm ).

Furthermore, similarly, 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.

(cerium oxide particles)

Referring to JP 2011-132107 A, experiments were performed as follows.

216 g of cerium(III) chloride heptahydrate was placed in 10 L of distilled water and stirred to dissolve. Furthermore, while continuing stirring, the temperature was raised to 93° C., and the entire amount of 5.6 kg of a 1.0% sodium hydroxide aqueous solution was added at once. In addition, after stirring at 93 degreeC for 6 hours, it cooled to 25 degreeC, and the white precipitate was obtained.

The precipitate was separated by a centrifugal separator, 15 L of distilled water was added to the obtained precipitate and stirred, and after redispersion, the precipitate was separated by a centrifugal separator. This operation was performed a total of 3 times to wash away the precipitate.

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 cerium oxide particle dispersion (Cp4) with a solid content concentration of 12% by mass. The average particle diameter according to the dynamic light scattering method was 34 nm.

(Formation of hard coating)

On the surface of the polyester film manufactured in the following examples, which is opposite to the polarizer bonding surface, use a # 10 wire bar to coat the coating solution for forming a hard coat layer with the following composition, and dry at 70°C for 1 minute to remove the solvent . Next, the film coated with the hard coat layer was irradiated with ultraviolet rays of 300 mJ/cm ² using a high-pressure mercury lamp to obtain a polarizer protective film having a hard coat layer with a thickness of 5 μm.

‧Coating solution for forming hard coat layer

(Example 1) Raw material of coating liquid

‧Particle A aqueous dispersion: zirconia/titania mixed particles (Cp1) with an average particle size of 23nm

(The amount of zirconia in zirconia/titania is 75% by mass, and the solid content concentration is 13% by mass)

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

‧Aqueous polyester dispersion ((Bw1), solid content concentration 25% by mass)

‧Aqueous polyurethane dispersion ((A1), solid content concentration: 37% by mass)

‧Blocked isocyanate-based crosslinking agent ((Cx1), solid content concentration 40% by mass)

(1) Adjustment of the coating solution for the easy-adhesive layer

The coating solution with the following composition was adjusted.

(2) Manufacture of easy-adhesive polyester film

As the raw material polymer for the film, PET resin pellets with an intrinsic viscosity (solvent: phenol/tetrachloroethane = 60/40) of 0.62dl/g and substantially no particles were used at 135°C under a reduced pressure of 133Pa. Let dry for 6 hours. Then, it was supplied to an extruder, melted and extruded into a sheet form at about 280°C, and rapidly cooled on a rotating cooling metal roll maintained at a surface temperature of 20°C to adhere and solidify to obtain an unstretched PET sheet.

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

Next, the aforementioned coating solution was applied to one side of the PET film by a roll coating method, and then dried at 80° C. for 15 seconds. In addition, it adjusted so that the coating weight after drying after final stretching might become 0.12 g/ ^m2 . Then, stretch to 4.0 times in the width direction with a tenter at 150°C, heat at 230°C for 0.5 seconds with the length of the film fixed in the width direction, and relax at 230°C for 10 seconds by 3% in the width direction After treatment, an optically adhesive polyester film with a thickness of 38 μm was obtained. The polyurethane resin component, polyester resin component, and other components in the coating layer are as described in Table 2, and are 20% by mass, 30% by mass, and 50% by mass, respectively.

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

Except having changed the ratio of the polyurethane resin component in an application layer, a polyester resin component, and other components into Table 2 or 3, it carried out similarly to Example 1, and obtained the easily-adhesive polyester film.

(Example 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.

(Embodiment 8~12)

Except having changed the kind of particle A of the coating liquid, and having changed the composition of each component in the coating layer as shown in Table 2, it carried out similarly to Example 1, and obtained the easy-adhesive polyester film.

(Example 13~15)

Except having changed the film thickness of the coating layer as shown in Table 2, it carried out similarly to Example 1, and obtained the easily-adhesive polyester film.

(Example 16, 17)

Except having changed the quantity of the particle B in an application layer to Table 2, it carried out similarly to Example 1, and obtained the easily-adhesive polyester film.

(Example 26, 27)

Except having changed the kind of the copolymerization polyester resin component as shown in Table 3, it carried out similarly to Example 1, and obtained the easy-adhesive polyester film.

(Example 28)

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

Tables 2 and 3 show the respective results. Moreover, the plotting of each Example and a comparative example on the triangular graph is shown in FIG. 1.

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

In addition, the coefficient of friction of the polyester films obtained in Examples and Comparative Examples is based on JIS K7125-1999 plastic film and sheet friction coefficient test method, using Tensilon (Toyo Baldwin, RTM-100) to measure, and any film has a static coefficient of friction (μs) is 0.35~0.5, and the dynamic friction coefficient (μd) is in the range of 0.45~0.6, and there is no problem in the roll-up and operability.

Industrial Utilization Possibility

According to the present invention, it is possible to provide low interference that can suppress rainbow spots, transparency, anti-adhesion, adhesion with various functional layers, and excellent sliding properties, and it is suitable for optical applications, especially polarizer protective films. Non-toxic polyester film and the above-mentioned laminated polyester film.

P1‧‧‧The line passing through the coordinates (10,55,35) and (10,10,80)

Q1‧‧‧The line passing through the coordinates (10,10,80) and (70,10,20)

R1‧‧‧The line passing through the coordinates (70,10,20) and (50,40,10)

S1‧‧‧The line passing through the coordinates (45,45,10) and (10,55,35)

○‧‧‧Plotting of each embodiment

□‧‧‧Plotting of each comparative example

Numerical values in the triangle graph‧‧‧number of each embodiment or each comparative example

Claims (6)

An easily bondable polyester film, which has a coating layer on at least one side of the polyester film, and the coating layer contains a polyurethane resin with a polycarbonate skeleton and a polyester resin with a naphthalene skeleton. When the total solid content of the layer is 100% by mass, the content (mass %) of the polyurethane resin component is defined as a, and the content (mass %) of the polyester resin component having a naphthalene skeleton is defined as b. The total amount (mass %) of the ingredients other than etc. is regarded as c, and when expressed in a triangular diagram, a, b, and c are in the area surrounded by four straight lines: straight line P1, straight line Q1, straight line R1, and straight line S1. When the total solid content of the coating layer is 100% by mass, the content b of the polyester resin component having a naphthalene skeleton is 45% by mass or less; here, the straight line P1, straight line Q1, straight line R1, and straight line S1 are as follows: Straight line P1: through Straight line Q1 between the point where a is 10% by mass, b is 55% by mass, and c is 35% by mass, and the point where a is 10% by mass, b is 10% by mass, and c is 80% by mass: Passing through a is 10% by mass , b is 10% by mass, c is 80% by mass, and a is 70% by mass, b is 10% by mass, and c is 20% by mass. Straight line R1: passing through a at 70% by mass and b at 10% by mass %, c is 20% by mass, and a is 50% by mass, b is 40% by mass, and c is 10% by mass. Straight line S1: Pass a at 45% by mass, b at 45% by mass, and c at 10% by mass The point of mass % and a is 10 mass %, b is 55 mass %, c A straight line at the point of 35% by mass. The easily adhesive polyester film according to claim 1, wherein the coating layer contains a crosslinking agent. The easily-adhesive polyester film according to claim 1 or 2, wherein the coating layer contains metal oxide particles (particles A) with a refractive index of 1.7 or higher. The easily-adhesive polyester film according to claim 1 or 2, wherein the coating layer contains slip agent particles (particles B). The easily-adhesive polyester film according to claim 3, wherein the coating layer contains slip agent particles (particles B). A laminated polyester film, which is on the coating layer of the easy-to-adhesive polyester film according to any one of claims 1 to 5, and has a coating layer selected from hard coating, anti-glare layer, anti-glare anti-reflection layer, anti-glare One or more functional layers of a group consisting of a reflective layer and a low reflective layer.

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