KR20230026313A - Laminated polyester film for optics - Google Patents

Abstract

An object of the present invention is to provide a laminated polyester film for optics having high transparency, resistance to blocking, and excellent adhesion to a hard coat layer, a light diffusion layer, a lens layer, an anti-glare layer, and a transparent conductive layer. In the present invention, at least one layer selected from a hard coat layer, a light diffusion layer, a lens layer, an anti-glare layer, and a transparent conductive layer is applied to the coating layer of an easily-adhesive polyester film having an application layer on at least one surface of a polyester film base material. It is a laminated polyester film for optics in which an optical function layer of is laminated, and the coating layer has a specific composition.

Description

Laminated polyester film for optics

The present invention relates to a laminated polyester film for optics having excellent adhesion and transparency. Specifically, it relates to a laminated polyester film for optics in which an optically functional film such as a hard coat film, a light diffusion sheet, a lens sheet, a transparent conductive film, or an antiglare film is laminated on a coating layer of an easily adhesive polyester film.

In general, substrates of optical functional films used as members of various displays such as liquid crystal displays include polyethylene terephthalate (PET), acrylic, polycarbonate (PC), triacetyl cellulose (TAC), polyolefin, and the like. A transparent thermoplastic resin film is used.

In the case of using the thermoplastic resin film as a base material for various optical functional films, functional layers according to various uses are laminated. For example, in a liquid crystal display, functional layers, such as a protective film (hard coat layer) which prevents surface flaws, a prism layer used for condensing and diffusing light, and a light diffusion layer which improves brightness, are mentioned. Among these substrates, polyester films in particular are widely used as substrates for various optical functional films because they are excellent in transparency, dimensional stability, and chemical resistance, and are relatively inexpensive.

In general, since the surface of the biaxially oriented polyester film is highly crystalline, there is a drawback that adhesion to various paints, adhesives, and the like is poor. For this reason, conventionally, a method of imparting ease of adhesion to the surface of a biaxially oriented polyester film by various methods has been proposed.

Conventionally, a technique for imparting ease of adhesion to a hard coat process, a prism lens process, etc. by using a co-polyester resin and a urethane resin for a coating layer has been known (for example, see Patent Document 1). However, this prior art had a problem that the blocking resistance of the easily-adhesive polyester film was not excellent.

In addition, a technique for imparting ease of adhesion to a hard coat process used in manufacturing a front sheet for a solar cell, in particular, by using a urethane resin and a blocked isocyanate in the coating layer has also been known (see, for example, Patent Document 2). However, in this prior art, there was a problem that the transparency of the easily-adhesive polyester film was low. In addition, a technique for improving adhesion to the lens layer by using a urethane resin and a blocked isocyanate for the coating layer is known (see Patent Document 3, for example). However, in this prior art, there was a problem that adhesion to the lens layer was insufficient.

Japanese Unexamined Patent Publication No. 2000-229355 Japanese Unexamined Patent Publication No. 2016-015491 Japanese Unexamined Patent Publication No. 2014-221560

The present invention is made against the background of these prior art problems. That is, an object of the present invention is to provide a laminated polyester film for optics using an easily-adhesive polyester film having high transparency, blocking resistance, and good adhesion to various optical resin compositions.

In order to solve the above problems, the present inventors, in the process of examining the causes of the above problems, etc., contain a crosslinking agent, a urethane resin having a polycarbonate structure, and a polyester resin on at least one side of the polyester film base material The problem of the present invention can be solved when the application layer has a coating layer, and the nitrogen atom ratio in the coating layer and the OCOO bond ratio on the surface of the coating layer on the opposite side to the polyester film substrate satisfy specific conditions. discovered and reached the completion of the present invention.

The above problem can be achieved by the following solutions.

1. At least one layer selected from a hard coat layer, a light diffusion layer, a lens layer, an anti-glare layer, and a transparent conductive layer in the coating layer of an easily-adhesive polyester film having a coating layer on at least one side of a polyester film base material. A laminated polyester film for optics in which an optical function layer is laminated, wherein the coating layer is formed by curing a composition containing a urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin, and X-ray to the coating layer In the distribution curve of the nitrogen element based on element distribution measurement in the depth direction by photoelectron spectroscopy, the nitrogen atom ratio on the surface of the coating layer on the opposite side to the polyester film substrate is A (at%), and the maximum value of the nitrogen atom ratio is B (at%), the etching time when the nitrogen atomic ratio shows the maximum value B (at%) is b (sec), and the etching time when the nitrogen atomic ratio becomes 1/2B (at%) after b (sec) is c When (sec) is expressed, the sum of the peak areas derived from each binding species in the C1s spectral region in the surface analysis spectrum that satisfies the following formulas (i) to (iii) and is measured by X-ray photoelectron spectroscopy is 100 The laminated polyester film for optics that satisfies the following formula (iv) when it is set as (%) and the peak area derived from the OCOO bond is set as X (%).

(i) 0.5≤B-A(at%)≤3.0

(ii) 30≤b(sec)≤180

(iii) 30 ≤ c-b (sec) ≤ 300

(iv) 2.0≤X(%)≤10.0

2. The said 1st laminated polyester film for optics whose haze of the said easily-adhesive polyester film is 1.5 (%) or less.

The easily-adhesive polyester film in the present invention has high transparency, has blocking resistance, and has good adhesion to various optical resin compositions. Therefore, the laminated polyester film for optics of the present invention using the easily-adhesive polyester film has excellent adhesion between the coating layer and various functional layers, and is suitable as an optical member such as a display.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a distribution curve of nitrogen elements based on elemental distribution measurement in the depth direction by X-ray photoelectron spectroscopy for an easily adhesive polyester film of Example 2.
2 is an explanatory diagram for determining BA, b, and cb from a distribution curve of nitrogen elements based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy.
3 is a distribution curve of nitrogen elements based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy for the easily adhesive polyester film of Example 5.
Figure 4 is a distribution curve of the nitrogen element based on the element distribution measurement in the depth direction by X-ray photoelectron spectroscopy for the easily adhesive polyester film of Experimental Example 6.
Fig. 5 is a graph showing the analysis results of the C1s spectrum of the surface region of the coating layer of the easily-adhesive polyester film of Example 6.
Figure 6 is a graph showing the analysis results of the C1s spectrum of the surface area of the coating layer of the easily adhesive polyester film of Experimental Example 1.

(Polyester film substrate)

In the present invention, the polyester resin constituting the polyester film base material is polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polytrimethylene terephthalate, etc., as well as the above polyester resins. It is a copolymerized polyester resin in which a part of the diol component or dicarboxylic acid component is substituted with the following copolymerization component, for example, as the copolymerization component, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, poly and diol components such as alkylene glycol, dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, 5-sodium isophthalic acid, and 2,6-naphthalenedicarboxylic acid.

The polyester resin preferably used in the present invention is mainly selected from polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. Among these polyester resins, polyethylene terephthalate is most preferable from the balance of physical properties and cost. In addition, the polyester film substrate composed of these polyester resins is preferably a biaxially stretched polyester film, and chemical resistance, heat resistance, mechanical strength and the like can be improved.

The catalyst for polycondensation used in the production of the polyester resin is not particularly limited, but antimony trioxide is suitable because it is inexpensive and has excellent catalytic activity. Moreover, it is also preferable to use a germanium compound or a titanium compound. A more preferable polycondensation catalyst includes a catalyst containing aluminum and/or a compound thereof and a phenolic compound, a catalyst containing aluminum and/or a compound thereof and a phosphorus compound, and a catalyst containing an aluminum salt of a phosphorus compound. Particularly preferably, transparency of the film can be improved by using a catalyst containing aluminum and/or a compound thereof and a phosphorus compound.

In addition, the polyester film base material in the present invention may be a single layer polyester film, may be a two-layer structure with mutually different components, or may be a polyester film base material composed of at least three layers having an outer layer and an inner layer.

(Description of characteristic values in the present invention)

It is preferable that the easily adhesive polyester film in this invention has a coating layer on at least one surface of the above polyester film base material. The coating layer is obtained by curing a composition containing a urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin. Here, the expression “the composition is cured” means that the urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin form a crosslinked structure with the crosslinking agent and accurately express the chemical composition in a cured state. Because it is very difficult to do. And, the maximum value of the distribution curve of the nitrogen element based on the element distribution measurement in the depth direction of the coating layer exists near the surface of the coating layer on the opposite side to the polyester film substrate, transparency, blocking resistance, hard coat layer , an anti-glare layer, an improvement in adhesion to a transparent conductive layer, etc. can be realized, which is preferable. In addition, it is preferable that an appropriate amount of the polycarbonate structure is present on the surface of the coating layer on the opposite side to the polyester film base material, in order to realize improved adhesion to the lens layer, the light diffusion layer, and the like.

The characteristics of the coating layer in the said easily-adhesive polyester film are demonstrated. First, a nitrogen element distribution curve based on element distribution measurement in the depth direction of the coating layer is drawn by X-ray photoelectron spectroscopy (ESCA). That is, spectrum collection is performed every 30 seconds until the etching time of 120 seconds, and every 60 seconds thereafter. And, as shown in FIG. 2, the ratio of the amount of nitrogen atoms to the total amount of carbon atoms, oxygen atoms, nitrogen atoms, and silicon atoms (nitrogen atoms Ratio, unit: at%) is taken on the vertical axis, A (at%) is the nitrogen atom ratio on the surface of the coating layer on the opposite side to the polyester film base material, B (at%) is the maximum value of the nitrogen atom ratio, and the nitrogen atom ratio is The etching time showing the maximum value B (at%) is b (sec), and the etching time when the nitrogen atom ratio becomes 1/2B (at%) after b (sec) is c (sec). From the read data, B-A (at%) and c-b (second) are calculated and obtained. The nitrogen atom ratio A (at%) on the surface of the coating layer on the opposite side to the polyester film substrate is the nitrogen atom ratio at an etching time of 0 (second).

And, when each characteristic value read from the distribution curve of the nitrogen element based on the element distribution measurement in the depth direction of the coating layer has the following relationship, transparency, blocking resistance, hard coat layer, light diffusion layer, lens layer, anti-glare An easily-adhesive polyester film excellent in adhesion to the layer and the transparent conductive layer is obtained.

(i) 0.5≤B-A(at%)≤3.0

(ii) 30≤b(sec)≤180

(iii) 30 ≤ c-b (sec) ≤ 300

The lower limit of B-A is preferably 0.5 at%, more preferably 0.6 at%, still more preferably 0.7 at%, particularly preferably 0.8 at%, and most preferably 0.9 at%. When it is 0.5 at% or more, the amount of the urethane resin component having toughness is satisfied and blocking resistance is obtained, which is preferable. In addition, it is preferable because the adhesion to the hard coat layer, the anti-glare layer, and the transparent conductive layer is also improved. The upper limit of B-A is preferably 3.0 at%, more preferably 2.9 at%, still more preferably 2.8 at%, particularly preferably 2.7 at%, and most preferably 2.5 at%. When it is 3.0 at% or less, the haze is low and transparency is obtained, which is preferable.

The lower limit of b is preferably 30 seconds, and if it is 30 seconds or more, the toughness of the surface of the coating layer on the opposite side to the polyester film substrate is maintained, and blocking resistance is obtained, which is preferable. The upper limit of b is preferably 180 seconds, more preferably 120 seconds, still more preferably 90 seconds, and particularly preferably 60 seconds. If it is 180 seconds or less, the toughness of the surface of the coating layer on the opposite side to the polyester film base material is maintained, and blocking resistance becomes good, and it is preferable. In addition, it is preferable because the adhesion to the hard coat layer, the anti-glare layer, and the transparent conductive layer is improved.

The upper limit of c-b is preferably 300 seconds, more preferably 240 seconds, still more preferably 180 seconds. When it is 300 seconds or less, the urethane resin component in the coating layer does not become excessive, and the haze is low and transparency is obtained, which is preferable. The lower limit of c-b is 30 seconds or more since spectrum collection is every 30 seconds from the start of measurement to the etching time of 120 seconds.

In this invention, it is preferable that most of the polycarbonate structure part in the urethane resin in the coating layer which comprises an easy-adhesive polyester film is localized on the surface of the coating layer on the opposite side to the polyester film base material. It is because the adhesiveness with respect to a lens layer and a light-diffusion layer improves because an appropriate amount of polycarbonate structure part exists in the said surface. On the other hand, it was also found that there are cases in which the presence of a polycarbonate structural part on the surface increases the flexibility and the blocking resistance is not necessarily sufficient. So, as described above, when each characteristic value read from the distribution curve of nitrogen element based on element distribution measurement in the depth direction of the coating layer has the following relationship, transparency, blocking resistance, hard coat layer, anti-glare layer, An excellent easily-adhesive polyester film also provided with adhesiveness with a transparent conductive layer is obtained.

(i) 0.5≤B-A(at%)≤3.0

(ii) 30≤b(sec)≤180

(iii) 30 ≤ c-b (sec) ≤ 300

In the easily adhesive polyester film of the present invention, as a means for satisfying the above formulas (i) to (iii), when synthesizing and polymerizing a urethane resin having a polycarbonate structure forming a coating layer, poly It is synthesized and polymerized by including the carbonate polyol component and the polyisocyanate component, the mass ratio of the polycarbonate polyol component and the polyisocyanate component is in the range of 0.5 to 2.5, and the molecular weight of the polycarbonate polyol component is 500 to 1800 And when the total solid content of the polyester resin, the urethane resin, and the crosslinking agent in the coating liquid is 100% by mass, the content of the solid content of the crosslinking agent is 10 to 50% by mass. And by using a block isocyanate as a crosslinking agent and using a block isocyanate having a trifunctional or higher functional isocyanate group, efficient control of B-A becomes possible.

In addition, as described above, most of the polycarbonate structure portion in the urethane resin in the coating layer in the present invention preferably exists in a certain proportion on the surface of the coating layer on the opposite side to the polyester film substrate. . In the present invention, in the surface analysis spectrum measured by X-ray photoelectron spectroscopy, the sum of peak areas derived from each bond species in the C1s spectrum region is 100 (%), derived from OCOO bond (polycarbonate structure) The peak area to be X (%) is expressed as a percentage.

Here, the ratio X (%) of OCOO bonds (of polycarbonate structure) in the surface area is evaluated by X-ray photoelectron spectroscopy (ESCA). 5 and 6 are examples of graphs showing analysis results of the C1s spectrum of the surface region of the easily-adhesive polyester film of Example 6 and Experimental Example 1 described later, respectively. The gray solid line represents the measured data of the C1s spectrum. The peak of the obtained measured spectrum is separated into a plurality of peaks, and the binding species corresponding to each peak is identified from the position and shape of each peak. In addition, by performing curve fitting on the peaks derived from each binding species, the peak area can be calculated. The coating layer in the present invention contains a urethane resin having a polycarbonate structure, a crosslinking agent represented by a block isocyanate having a trifunctional or higher functional isocyanate group, and a polyester resin. In the case of such a coating layer, Table 1 Peaks of the bound species of peaks (1) to (6) can be detected. The binding species of peaks (1) to (6) in Table 1 may contain not only the binding species shown in Table 1, but also some similar binding species. Here, in FIG. 5 relating to Example 6, the C=O bond peak of (3) of Table 1 and the π-π* bond peak of (6) are not shown. In addition, in FIG. 6 related to Experimental Example 1, the C=O bond peak of (3) of Table 1 and the OCOO bond peak of (5) are not shown. The ratio X (%) of OCOO bonds in the surface area can be said to be the percentage (%) of the area ratio of peak (5) when the entire peak area from peaks (1) to (6) is 100%. there is.

Preferable ranges of the peak area X (%) derived from OCOO bonds are as follows. The lower limit of X is preferably 2.0%, more preferably 2.5%, even more preferably 3.0%, particularly preferably 3.5%, and most preferably 4.0%. If it is 2.0% or more, the adhesiveness to a lens layer and a light-diffusion layer can be effectively satisfied, and is preferable. The upper limit of X is preferably 10.0%, more preferably 9.0%, still more preferably 8.0%, particularly preferably 7.5%, and most preferably 7%. When it is 10.0% or less, the flexibility of the surface layer does not increase too much, and blocking resistance is easily obtained, which is preferable.

As a manufacturing method of the easily adhesive polyester film in this invention, when synthesizing and polymerizing the urethane resin which has a polycarbonate structure which forms a coating layer, the mass ratio of a polycarbonate polyol component and a polyisocyanate component is 0.5 As described above, when the total solid content of the polyester resin, the urethane resin having a polycarbonate structure, and the crosslinking agent in the coating liquid is 100% by mass, the urethane resin content is 5% by mass to 50% by mass, the C1s spectrum This is preferable because the X characteristic value based on the region can be effectively realized in the range of 2.0 to 10.0%.

(applied layer)

The easily-adhesive polyester film in the present invention is a urethane resin having a polycarbonate structure on at least one side thereof in order to improve adhesion to the hard coat layer, adhesion to the lens layer, and adhesion to the light diffusion layer, It is preferable that a coating layer formed of a crosslinking agent and a composition containing a polyester resin is laminated. The coating layer may be provided on both sides of the polyester film, or may be provided on only one side of the polyester film, and a different type of resin coating layer may be provided on the other side.

Hereinafter, each composition of the coating layer is explained in detail.

(urethane resin)

The urethane resin having a polycarbonate structure in the present invention has at least a urethane bond portion derived from a polycarbonate polyol component and a polyisocyanate component, and optionally contains a chain extender.

The mass ratio of the polycarbonate polyol component and the polyisocyanate component (mass of the polycarbonate polyol component/mass of the polyisocyanate component) at the time of synthesizing and polymerizing the urethane resin having a polycarbonate structure in the present invention The lower limit is preferably 0.5, more preferably 0.6, still more preferably 0.7, particularly preferably 0.8, and most preferably 1.0. When it is 0.5 or more, the ratio X of OCOO bonds on the surface of the coating layer can be efficiently adjusted to 2% or more, which is preferable. The upper limit of the mass ratio of the polycarbonate polyol component and the polyisocyanate component at the time of synthesizing and polymerizing the urethane resin having a polycarbonate structure in the present invention is preferably 2.5, more preferably 2.2, and further It is preferably 2.0, particularly preferably 1.7, and most preferably 1.5. If it is 2.5 or less, the ratio X of OCOO bonds on the surface of the coating layer can be efficiently adjusted to 10% or less, which is preferable. Also, in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy, B-A can be effectively adjusted to 0.5 at% or more, and c-b can be effectively adjusted to 300 seconds or less.

The polycarbonate polyol component used to synthesize and polymerize the urethane resin having a polycarbonate structure in the present invention preferably contains an aliphatic polycarbonate polyol having excellent heat resistance and hydrolysis resistance. . Examples of the aliphatic polycarbonate polyol include aliphatic polycarbonate diols and aliphatic polycarbonate triols, but aliphatic polycarbonate diols can be preferably used. Examples of the aliphatic polycarbonate diol used to synthesize and polymerize the urethane resin having a polycarbonate structure in the present invention include ethylene glycol, propylene glycol, 1,3-propanediol, and 1,4 -butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, aliphatic polycarbonate diols obtained by reacting one or two or more diols such as dipropylene glycol with carbonates such as dimethyl carbonate, ethylene carbonate and phosgene; can

The number average molecular weight of the polycarbonate polyol in the present invention is preferably 500 to 1800. More preferably, it is 600 to 1700, and most preferably 700 to 1500. When it is 500 or more, the ratio X of OCOO bonds on the surface of the coating layer can be effectively adjusted to 10% or less, which is preferable. If it is 1800 or less, in the nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy, B-A can be effectively adjusted to 0.5 or more and c-b to 300 seconds or less, which is preferable.

Examples of the polyisocyanate used in the synthesis and polymerization of the urethane resin having a polycarbonate structure in the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 4,4-dic Alicyclic diisocyanates such as chlorohexylmethane diisocyanate and 1,3-bis(isocyanatomethyl)cyclohexane, aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate or polyisocyanates obtained by previously adding trimethylolpropane or the like to these compounds singly or in plural numbers. When the above aromatic aliphatic diisocyanates, alicyclic diisocyanates, or aliphatic diisocyanates are used, there is no problem of yellowing, which is preferable. In addition, it is preferable because it does not form an excessively rigid coating film, the stress due to heat shrinkage of the polyester film base material can be relieved, and the adhesiveness is good.

Examples of the chain extender include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol and 1,6-hexanediol, polyhydric alcohols such as glycerin, trimethylolpropane and pentaerythritol, and ethylenediamine , diamines such as hexamethylenediamine and piperazine, amino alcohols such as monoethanolamine and diethanolamine, thiodiglycols such as thiodiethylene glycol, or water.

It is preferable to provide the coating layer in this invention by the in-line coating method mentioned later using a water-system coating liquid. Therefore, the urethane resin of the present invention preferably has water solubility or water dispersibility. In addition, the said "water solubility or water dispersibility" means being disperse|distributed with respect to the aqueous solution containing less than 50 mass % of water or a water-soluble organic solvent.

In order to impart water dispersibility to the urethane resin, a sulfonic acid (salt) group or a carboxylic acid (salt) group can be introduced (copolymerized) into the urethane molecular skeleton. In order to maintain moisture resistance, it is suitable to introduce a weakly acidic carboxylic acid (salt) group. In addition, nonionic groups such as polyoxyalkylene groups may 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 dimethylolpropanoic acid or dimethylolbutanoic acid is introduced as a copolymerization component, and neutralize Specific examples of the salt forming agent include ammonia, trialkylamines such as trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine and tri-n-butylamine, N-methylmorpholine and N-ethylmorpholine. N-alkyl morpholines such as pholine, and N-dialkyl alkanolamines such as N-dimethylethanolamine and N-diethylethanolamine. These can be used independently and can also be used together 2 or more types.

When a polyol compound having a carboxylic acid (salt) group is used as a copolymerization component to impart water dispersibility, the composition molar ratio of the polyol compound having a carboxylic acid (salt) group in the urethane resin is the total polyisocyanates of the urethane resin When a component is 100 mol%, it is preferable that it is 3-60 mol%, and it is more preferable that it is 5-40 mol%. When the molar ratio of the composition is less than 3 mol%, water dispersibility may become difficult. Moreover, since water resistance falls when the said composition molar ratio exceeds 60 mol%, heat-and-moisture resistance may fall.

In the urethane resin of the present invention, a block isocyanate may be bonded to the terminal to improve rigidity.

(crosslinking agent)

In the present invention, the crosslinking agent contained in the composition for forming a coating layer is preferably a block isocyanate, more preferably a trifunctional or higher functional block isocyanate, and particularly preferably a tetrafunctional or higher functional block isocyanate. While blocking resistance improves by these, adhesiveness with a hard coat layer, an anti-glare layer, and a transparent conductive layer improves. The use of a blocked isocyanate crosslinking agent is preferable because B-A can be effectively adjusted to 0.5 at% or more in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy.

The lower limit of the boiling point of the blocking agent of the blocked isocyanate is preferably 150°C, more preferably 160°C, still more preferably 180°C, particularly preferably 200°C, and most preferably 210°C. As the boiling point of the blocking agent is higher, the volatilization of the blocking agent is suppressed even by the application of heat in the drying step after application of the coating liquid or in the film forming step in the case of the in-line coating method, and the occurrence of minute irregularities on the coated surface is suppressed, Transparency of the film is improved. Although the upper limit of the boiling point of the blocking agent is not particularly limited, it is considered that about 300°C is the upper limit in terms of productivity. Since the boiling point is related to the molecular weight, in order to increase the boiling point of the blocking agent, it is preferable to use a blocking agent having a high molecular weight, and the molecular weight of the blocking agent is preferably 50 or more, more preferably 60 or more, and 80 or more. more preferable

The upper limit of the dissociation temperature of the blocking agent is preferably 200°C, more preferably 180°C, still more preferably 160°C, particularly preferably 150°C, and most preferably 120°C. The blocking agent is dissociated from the functional group by the application of heat in the drying step after application of the coating liquid or in the case of the in-line coating method in the film forming step to generate regenerated isocyanate groups. Therefore, a crosslinking reaction with a urethane resin or the like proceeds, and the adhesiveness is improved. When the dissociation temperature of the blocked isocyanate is equal to or lower than the above temperature, since the dissociation of the blocking agent sufficiently proceeds, the adhesiveness, particularly heat-and-moisture resistance becomes good.

Blocking agents having a dissociation temperature of 120°C or lower and a boiling point of the blocking agent used for the blocked isocyanate of the present invention of 150°C or higher include bisulfite-based compounds: sodium bisulfite, etc., pyrazole-based compounds: 3,5-dimethylpyrazole , 3-methylpyrazole, 4-bromo-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, etc., active methylene-based: malonate diester (dimethyl malonate, diethyl malonate, malon di-n-butyl acid, di-2-ethylhexyl malonate), methyl ethyl ketone, etc. Triazole type compound: 1,2,4-triazole etc. are mentioned. Among them, a pyrazole-based compound is preferable from the viewpoint of heat-and-moisture resistance and yellowing.

The polyisocyanate, which is a precursor of the block isocyanate of the present invention, is obtained by introducing diisocyanate. For example, a urethane modified form of diisocyanate, an allophanate modified form, a urea modified form, a biuret modified form, a uretdione modified form, a urethimine modified form, an isocyanurate modified form, a carbodiimide modified form, etc. can be heard

As diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane Diisocyanate, 1,5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, phenylene diisocyanate, tetramethylxylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4 ,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, aromatic diisocyanates such as 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and 4,4-dicyclo alicyclic diisocyanates such as hexylmethane diisocyanate and 1,3-bis(isocyanatomethyl)cyclohexane; aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; can be heard From the viewpoint of transparency, adhesiveness, and heat-and-moisture resistance, aliphatic alicyclic isocyanates and modified products thereof are preferable, and are suitable for optics requiring high transparency without yellowing.

The block isocyanate in the present invention can introduce a hydrophilic group into the polyisocyanate as a precursor in order to impart water solubility or water dispersibility. Examples of hydrophilic groups include (1) quaternary ammonium salts of dialkylamino alcohols and quaternary ammonium salts of dialkylaminoalkylamines, (2) sulfonates, carboxylate salts, phosphates, etc., (3) polyethylene glycol capped at one end with an alkoxy group. , polypropylene glycol, etc. are mentioned. When a hydrophilic site is introduced, it becomes (1) cationic, (2) anionic, and (3) nonionic. Among them, since many other water-soluble resins are anionic, easily compatible anionic and nonionic resins are preferred. In addition, since the anionic property has excellent compatibility with other resins and the nonionic property does not have an ionic hydrophilic group, it is also preferable for improving heat-and-moisture resistance.

As the anionic hydrophilic group, those having a hydroxyl group for introducing into polyisocyanate and a carboxylic acid group for imparting hydrophilicity are preferable. Examples include glycolic acid, lactic acid, tartaric acid, citric acid, oxybutyric acid, oxyvaleric acid, hydroxypivalic acid, dimethylolacetic acid, dimethylolpropanoic acid, dimethylolbutanoic acid, and polycaprolactone having a carboxylic acid group. . In order to neutralize the carboxylic acid group, organic amine compounds are preferred. For example, ammonia, methylamine, ethylamine, propylamine, isopropylamine, butylamine, 2-ethylhexylamine, cyclohexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutyl amines, trimethylamine, triethylamine, triisopropylamine, tributylamine, linear, branched, primary, secondary or tertiary amines having 1 to 20 carbon atoms, such as morpholine, N-alkylmorpholine, cyclic amines such as pyridine; hydroxyl group-containing amines such as monoisopropanolamine, methylethanolamine, methylisopropanolamine, dimethylethanolamine, diisopropanolamine, diethanolamine, triethanolamine, diethylethanolamine, and triethanolamine; and the like. .

As the nonionic hydrophilic group, the number of repeating units of ethylene oxide and/or propylene oxide of polyethylene glycol or polypropylene glycol blocked at one end with an alkoxy group is preferably 3 to 50, more preferably 5 to 30. When the repeating unit is small, the compatibility with the resin deteriorates and the haze rises, and when the repeating unit is large, the adhesiveness under high temperature and high humidity may decrease. In order to improve the water dispersibility of the blocked isocyanate of the present invention, nonionic, anionic, cationic, or amphoteric surfactants may be added. For example, nonionic systems such as polyethylene glycol and polyhydric alcohol fatty acid esters, fatty acid salts, alkyl sulfate esters, alkylbenzenesulfonates, sulfosuccinates, and alkylphosphates, anionic systems, and cationic systems such as alkylamine salts and alkylbetaines. and surfactants such as carboxylate amine salts, sulfonic acid amine salts, and sulfuric acid ester salts.

In addition to water, a water-soluble organic solvent may be contained. For example, the organic solvent used in the reaction may be removed or another organic solvent may be added.

(polyester resin)

The polyester resin used to form the coating layer in the present invention may be linear, but more preferably is a polyester resin containing dicarboxylic acid and branched glycol as constituent components. The dicarboxylic acid referred to herein is terephthalic acid, isophthalic acid or other aliphatic dicarboxylic acids such as adipic acid and sebacic acid whose main component is 2,6-naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 2,6- Aromatic dicarboxylic acids, such as naphthalene dicarboxylic acid, are mentioned. In addition, the branched glycol is a diol having a branched alkyl group, for example, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-methyl-2 -Butyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl -1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl-1 ,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol and 2,2-di-n-hexyl- 1,3-propanediol etc. are mentioned.

It can be said that the polyester resin contains the branched glycol component, which is the more preferred embodiment, in an amount of preferably 10 mol% or more, more preferably 20 mol% or more, in all glycol components. As glycol components other than the above compounds, ethylene glycol is most preferred. As long as it is small, you may use diethylene glycol, propylene glycol, butanediol, hexanediol, or 1, 4- cyclohexane dimethanol.

As the dicarboxylic acid as a component of the polyester resin, terephthalic acid or isophthalic acid is most preferred. If it is small amount, you may copolymerize by adding another dicarboxylic acid, especially aromatic dicarboxylic acid, such as diphenylcarboxylic acid and 2, 6-naphthalenedicarboxylic acid. In addition to the above dicarboxylic acid, in order to impart water dispersibility to the copolymerized polyester resin, it is preferable to copolymerize 5-sulfoisophthalic acid in the range of 1 to 10 mol%, for example, sulfoterephthalic acid and 5-sulfoterephthalic acid. Poisophthalic acid, 4-sulfonaphthalene isophthalic acid-2,7-dicarboxylic acid, 5-(4-sulfophenoxy) isophthalic acid, salts thereof, and the like.

When the total solid content of the polyester resin, the urethane resin having a polycarbonate structure, and the crosslinking agent in the coating liquid is 100% by mass, the lower limit of the content of the crosslinking agent is preferably 5% by mass, more preferably 7% by mass. %, more preferably 10% by mass, and most preferably 12% by mass. When it is 5 mass% or more, it is easy to adjust B-A to 0.5 at% or more in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy, which is preferable. The upper limit of the content of the crosslinking agent is preferably 50% by mass, more preferably 40% by mass, still more preferably 35% by mass, and most preferably 30% by mass. If it is 50% by mass or less, in a nitrogen distribution curve based on element distribution measurement in the depth direction by X-ray photoelectron spectroscopy, it is easy to adjust c-b to 300 seconds or less, which is preferable.

When the total solid content of the polyester resin, the urethane resin having a polycarbonate structure, and the crosslinking agent in the coating liquid is 100% by mass, the lower limit of the content of the urethane resin having a polycarbonate structure is preferably 5% by mass am. When it is 5% by mass or more, it is easy to adjust the ratio X of OCOO bonds on the surface of the coating layer to 2.0% or more, which is preferable. The upper limit of the content of the urethane resin having a polycarbonate structure is preferably 50% by mass, more preferably 40% by mass, still more preferably 30% by mass, and most preferably 20% by mass. When the content rate of the urethane resin is 50% by mass or less, it is easy to adjust the ratio X of OCOO bonds on the surface of the coating layer to 10.0% or less, which is preferable.

When the total solid content of the polyester resin, the urethane resin and the crosslinking agent in the coating liquid is 100% by mass, the lower limit of the polyester resin content is preferably 10% by mass, more preferably 20% by mass, still more preferably is 30% by mass, particularly preferably 35% by mass, and most preferably 40% by mass. When the content rate of the polyester resin is 10% by mass or more, the adhesion between the coating layer and the polyester film base material becomes good, which is preferable. The upper limit of the content of the polyester resin is preferably 70% by mass, more preferably 67% by mass, still more preferably 65% by mass, particularly preferably 62% by mass, and most preferably 60% by mass. am. When the content rate of the polyester resin is 70% by mass or less, the heat-and-moisture resistance of the hard coat film after hard coat processing becomes good, which is preferable.

(additive)

In the coating layer in the present invention, known additives such as surfactants, antioxidants, heat-resistant stabilizers, weathering stabilizers, ultraviolet absorbers, organic lubricants, pigments, and dyes are contained within the range that does not impair the effects of the present invention. , organic or inorganic particles, antistatic agents, nucleating agents and the like may be added.

In the present invention, in order to further improve the blocking resistance of the coating layer, it is also a preferred embodiment to add particles to the coating layer. In the present invention, the particles to be contained in the coating layer are, for example, titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay, etc., or mixtures thereof, and further other general inorganic particles; For example, inorganic particles such as calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride, etc., and organic polymer particles such as styrene, acrylic, melamine, benzoguanamine, and silicon. etc. can be mentioned.

The average particle diameter of the particles in the coating layer (average particle diameter based on number as measured by a scanning electron microscope (SEM). The same applies hereinafter) is preferably 0.04 to 2.0 μm, more preferably 0.1 to 1.0 μm. When the average particle diameter of the inert particles is 0.04 μm or more, irregularities on the surface of the film are easily formed, handling properties such as slipperiness and winding properties of the film are improved, and workability during bonding is good, which is preferable. On the other hand, when the average particle diameter of the inert particles is 2.0 μm or less, it is difficult for the particles to fall off, which is preferable. It is preferable that the particle concentration in the coating layer is 1 to 20% by mass of the solid component.

The method of measuring the average particle size of the particles was performed by observing the particles of the cross section of the easily adhesive polyester film with a scanning electron microscope, observing 30 particles, and using the average value as the average particle size.

The shape of the particles is not particularly limited as long as the object of the present invention is satisfied, and spherical particles and irregularly shaped non-spherical particles can be used. The particle diameter of irregularly shaped particles can be calculated as an equivalent circle diameter. The equivalent circle diameter is a value obtained by dividing the area of the observed particle by π, calculating the square root, and doubling the result.

(Manufacture of easy-adhesive polyester film)

Although the example using the polyethylene terephthalate (it may abbreviate as PET below) film base material is given about the manufacturing method of the easily-adhesive polyester film in this invention, it demonstrates, naturally it is not limited to this.

After the PET resin is vacuum-dried sufficiently, it is supplied to an extruder, and the molten PET resin at about 280° C. is melt-extruded from the T die into a sheet form on a rotary cooling roll, and cooled and solidified by an electrostatic application method to obtain an unstretched PET sheet. The unstretched PET sheet may have a single-layer structure or a multi-layer structure by a co-extrusion method.

The obtained unstretched PET sheet is crystal oriented by uniaxial stretching or biaxial stretching. For example, in the case of biaxial stretching, after stretching 2.5 to 5.0 times in the longitudinal direction with a roll heated to 80 to 120 ° C. to obtain a uniaxially stretched PET film, the end of the film is held with a clip, and 80 to 180 It is guided to a hot air zone heated at °C and stretched 2.5 to 5.0 times in the width direction. In addition, in the case of uniaxial stretching, it is stretched 2.5 to 5.0 times in a tenter. After stretching, it is guided to a heat treatment zone and heat treatment is performed to complete the crystal orientation.

The lower limit of the temperature of the heat treatment zone is preferably 170°C, more preferably 180°C. When the temperature of the heat treatment zone is 170° C. or higher, the curing is sufficient and the blocking property in the presence of liquid moisture is good, which is preferable, and there is no need to lengthen the drying time. On the other hand, the upper limit of the temperature of the heat treatment zone is preferably 230°C, more preferably 200°C. When the temperature of the heat treatment zone is 230° C. or less, there is no risk of deterioration in physical properties of the film, which is preferable.

An application layer can be provided after manufacture of a film, or in a manufacturing process. In particular, from the viewpoint of productivity, it is preferable to form a coating layer by applying a coating liquid to at least one side of a PET film after any step in the film production process, that is, unstretched or uniaxially stretched.

As a method for applying this coating liquid to the PET film, any known method can be used. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method etc. can be mentioned. These methods can be applied individually or in combination.

In the present invention, the thickness of the coating layer can be appropriately set in the range of 0.001 to 2.00 μm, but in order to achieve both processability and adhesiveness, the range of 0.01 to 1.00 μm is preferable, more preferably 0.02 to 0.80 μm, More preferably, it is 0.05-0.50 micrometer. When the thickness of the coating layer is 0.001 μm or more, the adhesiveness is good and is preferable. When the thickness of the coating layer is 2.00 μm or less, it is difficult to cause blocking, which is preferable.

The upper limit of the haze of the easily-adhesive polyester film in the present invention is preferably 1.5%, more preferably 1.3%, still more preferably 1.2%, and particularly preferably 1.0%. If the haze is 1.5% or less, it is preferable from the point of transparency, and it can be used suitably also for the optical film which transparency is requested|required. A haze is preferably small, but may be 0.1% or more.

(laminated polyester film for optical use)

It is a preferable aspect to provide a functional layer on the application layer of the easily-adhesive polyester film in this invention. The functional layer refers to a layer having functionality such as a hard coat layer, an anti-glare layer, a light diffusion layer, and a transparent conductive layer for the purpose of preventing see-through, suppressing glare, suppressing rainbow spots, suppressing scratches, and the like. As the functional layer, various types known in the art can be used, and the type is not particularly limited. Hereinafter, each functional layer is demonstrated.

(hard coat layer)

For the formation of the hard coat layer, any known material for the hard coat layer can be used, and although not particularly limited, a resin that polymerizes and/or reacts by drying, heat, chemical reaction, or irradiation with any of electron beams, radiation, and ultraviolet rays. compound can be used. Examples of such curable resins include melamine-based, acrylic-based, silicone-based, and polyvinyl alcohol-based curable resins, but photocurable acrylic curable resins are preferred in view 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. Examples of the acrylate-based oligomer include polyester acrylates, epoxy acrylates, urethane acrylates, and polyethers. An acrylate type, a polybutadiene acrylate type, a silicone acrylate type, etc. are mentioned. The composition for coating for forming the said optical function layer can be obtained by mixing a reaction diluent, a photoinitiator, a sensitizer, etc. with these acrylic curable resins.

The hard coat layer preferably contains inorganic particles. Inorganic particles are blended to increase the hardness of the cured coating. For example, silica, aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, tin oxide, etc. can be mentioned, and it can be used individually or in combination of 2 or more types. Among these, silica and aluminum oxide are preferable from the viewpoint of having little effect on the optical properties. In the case of using silica, it is preferable to treat the surface with a silane-based coupling agent, an organic compound having a reactive functional group such as a (meth)acryloyl group, etc. in order to improve the dispersibility in the paint, but aluminum oxide is used. In this case, since the presence or absence of surface treatment has little effect on dispersibility, either can be used without problems.

The average particle diameter of the inorganic particles is preferably 5 to 200 nm, more preferably 10 to 100 nm, and particularly preferably 20 to 60 nm. By setting it as 5 nm or more, the improvement of film hardness can be expected, and by setting it as 200 nm or less, the influence on optical characteristics, such as a haze, can be lowered. Moreover, 0.5 to 10 weight% is preferable and, as for the compounding quantity with respect to the total solid content of an inorganic particle, 1 to 8 weight% is more preferable. By setting it as 0.5 weight% or more, the improvement of hardness can be expected, and by setting it as 10 weight% or less, the influence on optical characteristics, such as a haze, can be lowered. In addition, the average particle diameter is taken as the median diameter (d50) measured by the BET method in the case of silica and the laser diffraction/scattering method in accordance with JISZ8825-1 in the case of others containing aluminum oxide.

The hard coat layer may have an anti-glare function (anti-glare function) of scattering external light. The antiglare function (antiglare function) is obtained by forming irregularities on the surface of the hard coat layer. At this time, the haze of the film is ideally preferably 0 to 50%, more preferably 0 to 40%, particularly preferably 0 to 30%, and most preferably 1.5% or less. The lower limit may be 0.1% or more.

(light diffusion layer)

From the viewpoint of practicality as a base film for a light diffusion sheet, the upper limit of the thickness is preferably 250 µm. A particularly preferable upper limit of the thickness is 200 μm, which is equivalent to that of a general TAC film. It is preferable that at least one surface of the base material has a bead coat layer mainly containing acrylic resin beads and a binder, and that the light diffusion sheet has a haze of 80% or more. When the haze of the light diffusion sheet is 80% or more, the effect of improving the luminance is obtained and color unevenness does not occur, which is preferable. A more preferable lower limit is 85%.

Next, a method of forming a bead coat layer on the base polyester film as a light diffusion sheet will be described, but the present invention is not limited to this. Examples of the binder used in the bead coat layer include acrylic resins such as PMMA (polymethyl methacrylate), polyester resins, polyvinyl chloride, polyurethane, and various resins such as silicone resins. Acrylic resins have excellent transparency. is particularly suitable by

As beads to be included in the bead coat layer, it is preferable to use acrylic resins, but it is also possible to use other resins in combination. Examples of other resins include various resins such as silicone resins, nylon resins, urethane resins, styrene resins, polyethylene resins, silica particles, and polyester resins. The particle diameter of these beads is not particularly limited, but those with an average particle diameter of 1 μm to 50 μm are suitably used. In addition, when a spherical bead is used as the bead, the spherical bead acts as a kind of lens, and a more effective light diffusing effect can be provided.

By preparing a coating liquid in which the beads are blended with the above-mentioned binder in an appropriate number of blending units, uniformly applying this coating liquid to the surface of the coating layer of the easily-adhesive polyester film prepared as described above, and drying, A bead coat layer in which beads are uniformly dispersed is formed. The number of beads to be blended with the binder is not particularly limited, but is preferably about 10 to 60 parts by weight with respect to 100 parts by weight of the binder, considering the light diffusing performance. As the coating method, although various methods such as a roll coating method, a dipping method, a spray coating method, a spin coating method, a lamination method, and a pouring method can be used, it is not particularly limited.

The backlight of a liquid crystal display device using the light-diffusing sheet of the present invention has good luminance, little luminance change due to angle, and small luminance unevenness. Therefore, it becomes possible to contribute to higher luminance, higher quality, and lower cost of the liquid crystal.

(transparent conductive layer)

Examples of the transparent conductive thin film in the present invention include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Among these, from the viewpoint of environmental stability or circuit workability, indium-tin composite oxide is suitable. In the present invention, by laminating transparent conductive thin film layers and setting the surface resistance value of the transparent conductive laminated film to preferably 50 to 2000 Ω/□, more preferably 100 to 1500 Ω/□, it can be used as a transparent conductive laminated film for touch panels, etc. can When the surface resistance value is 50 Ω/□ or more and 2000 Ω/□ or less, the position recognition accuracy of the touch panel is good and preferable.

The film thickness of the transparent conductive thin film is preferably in the range of 4 to 30 nm, and more preferably in the range of 10 to 25 nm. When the film thickness of the transparent conductive thin film is 4 nm or more, continuous thin film formation is easy and good conductivity is obtained, which is preferable. On the other hand, when the film thickness of the transparent conductive thin film is 30 nm or less, when the transparent conductive layer is patterned, the difference in optical properties between the portion having the transparent conductive layer and the portion not having it is small, which is preferable.

The structure of the transparent conductive layer may be a single-layer structure or a laminated structure of two or more layers. In the case of a transparent conductive thin film having a laminated structure of two or more layers, the metal oxide constituting each layer may be the same or different.

As methods for forming a transparent conductive thin film in the present invention, vacuum deposition, sputtering, CVD, ion plating, and spraying are known, and these methods can be appropriately used depending on the required film thickness. In addition, a transparent conductive layer can also be laminated on the coating layer by a method of coating a conductive material such as an aniline-based compound, a thiol-based compound, a pyrrole-based compound, or carbon nanotube in a binder resin. For example, in the case of sputtering, a normal sputtering method using an oxide target or a reactive sputtering method using a metal target is used. At this time, oxygen, nitrogen, etc. may be introduced as a reactive gas, or means such as addition of ozone, plasma irradiation, or ion assist may be used in combination. Further, within a range that does not impair the object of the present invention, bias such as direct current, alternating current, or high frequency may be applied to the substrate.

The laminated polyester film for optics having a transparent conductive layer of the present invention is particularly suitable as an electrode film for a resistive or capacitive touch panel. In addition, laminating the hard coat layer on the coating layer of the easy-adhesive polyester film and laminating the transparent conductive layer on the hard-coat layer can suppress the precipitation of oligomers in the easy-adhesive polyester film, a particularly preferred embodiment can be said

(lens layer)

Although light from a backlight in a liquid crystal panel is directed in various directions, it is known as a preferable aspect to provide a lens sheet in order to concentrate this light toward the viewing side and increase the luminance of the display device. As the lens sheet, depending on the shape of the lens processed on the surface, a uniaxial condensing type such as a cylindrical lens, a prism lens, a lenticular lens, etc. A 2-axis light-concentrating type that concentrates light in two directions, a 3-axis light-concentrating type such as a triangular pyramid or a hexagonal pyramid, a multi-axis type such as an octagonal pyramid or more, and a small hemispherical or elliptical hemispherical microlens type, Fresnel lens type, etc. can, and all are used. The lens sheet may be formed by lens processing on not only one surface but also both surfaces, and the lenses may have different shapes on both surfaces. The uniaxial condensing type lens may be processed such that the condensing axes are orthogonal to both surfaces. Among these, a 2-axis type, a 3-axis type, a multi-axis type, and a microlens type have a high light-condensing effect, and are exemplified as particularly preferable lens shapes.

The lens layer in the present invention is, for example, a coating/shaping composition containing a thermoplastic resin having appropriate hardness and shapeability, or a reaction curable resin, etc., on a coating layer of an easily adhesive polyester film, for example. can be obtained by doing Various materials can be applied to the composition containing a thermoplastic resin or a reaction-curable resin having shapeability, but various curable resins as described in the description of the hard coat layer can be mentioned, and UV-curable acrylic resin is a representative example. Yes. In addition, a composition containing a monomer or oligomer for forming a UV-curable acrylic resin is introduced into the frame on which the pattern of the lens is formed, and the coated surface of the easy-adhesive polyester film is brought into close contact with the resin side thereon, and the easy-adhesive poly The lens layer may be formed by curing the composition by irradiating ultraviolet rays from the side of the ester film surface.

The lens sheet is a method of embossing the surface of a transparent substrate using a mold of a specific pattern, a method of applying an ultraviolet curable resin such as acrylic to an easily adhesive polyester film as described above and curing it by ultraviolet rays while bringing it into contact with a mold of a specific pattern, etc. can also be heard.

Although the shape of the lens layer is not particularly limited, for example, a prismatic lens, a Fresnel lens, a microlens or the like can be suitably applied.

From the above, the use of the laminated polyester film for optics of the present invention is mainly used throughout the optical film, such as a prism lens sheet, an anti-reflection (AR) film, a hard coat film, a diffusion plate, and an anti-shatter film, such as LCDs or flat films. It can be used suitably for the base film of optical members, such as TV and CRT, the near-infrared absorption filter which is a member of the front plate for plasma displays, and the transparent conductive film, such as a touch panel and electroluminescence.

Example

Next, the present invention will be described in detail using examples and experimental examples, but the present invention is not limited to the following examples.

[Production of Polyester Resin Pellets P-1]

In a 2-liter stainless steel autoclave equipped with a stirrer, high-purity terephthalic acid and 2-fold molar amount of ethylene glycol were charged, triethylamine was added in an amount of 0.3 mol% based on the acid component, and water was added at 250 ° C. under a pressure of 0.25 MPa. Esterification was carried out while distilling off to the outside to obtain a mixture of bis(2-hydroxyethyl) terephthalate and oligomers having an esterification rate of about 95% (hereinafter referred to as a BHET mixture). Next, while stirring this BHET mixture, an ethylene glycol solution of antimony trioxide as a polymerization catalyst was added in an amount of 0.04 mol% in terms of antimony atoms relative to the acid component in the polyester, and then 10% at 250°C at normal pressure in a nitrogen atmosphere. Stir for 1 minute. Thereafter, while raising the temperature to 280°C over 60 minutes, the pressure of the reaction system was gradually lowered to 13.3Pa (0.1 Torr), and a polycondensation reaction was further conducted at 280°C and 13.3Pa. Following the pressure relief, the resin under fine pressure was discharged into cold water in the form of strands to rapidly cool, and then kept in cold water for 20 seconds and then cut to obtain cylindrical pellets with a length of about 3 mm and a diameter of about 2 mm.

After drying the polyester pellets obtained by melt polymerization under reduced pressure (13.3 Pa or less, 80 ° C., 12 hours), subsequent crystallization treatment (13.3 Pa or less, 130 ° C., 3 hours, further 13.3 Pa or less, 160 ° C., 3 hours ) was performed. This polyester pellet after cooling was subjected to solid state polymerization in a solid state polymerization reactor while maintaining the inside of the system at 13.3 Pa or less and 215 ° C., thereby obtaining a polyester pellet (P-1) having an intrinsic viscosity of 0.62 dl/g.

[Preparation of Polyester Pellets P-2]

(Preparation of aluminum compound)

In a 20 g/l aqueous solution of basic aluminum acetate (hydroxyaluminum diacetate; manufactured by Aldrich), which was prepared by heating at 80 ° C. for 2 hours under stirring, and which was confirmed to have chemically shifted the peak position of the 27Al-NMR spectrum to the low field side. For this, an equal amount (volume ratio) of ethylene glycol was added to the flask together, and after stirring at room temperature for 6 hours, water was distilled off from the system while stirring for several hours at 90 to 110 ° C. under reduced pressure (133Pa) to obtain 20 g / l An ethylene glycol solution of the aluminum compound of was prepared.

(Preparation of phosphorus compound)

As a phosphorus compound, Irganox 1222 (manufactured by Ciba Specialty Chemicals) was put into a flask together with ethylene glycol and heated at a solution temperature of 160° C. for 25 hours while stirring under nitrogen substitution to prepare a 50 g/l ethylene glycol solution of the phosphorus compound. It was confirmed by measurement of 31 P-NMR spectrum that about 60 mol% was converted to hydroxyl groups.

(Preparation of mixture of ethylene glycol solution of aluminum compound/ethylene glycol solution of phosphorus compound)

Each of the ethylene glycol solutions obtained in the preparation of the aluminum compound and the preparation of the phosphorus compound were put into a flask, mixed at room temperature so that the molar ratio of aluminum atoms and phosphorus atoms was 1: 2, and stirred for 1 day to prepare a catalyst solution. . In the measurement results of the 27 Al-NMR spectrum and the 31 P-NMR spectrum of the mixed solution, chemical shifts were confirmed in both cases.

(Preparation of Pellets P-2)

As a polycondensation catalyst, a mixture of an ethylene glycol solution of an aluminum compound/an ethylene glycol solution of a phosphorus compound was used, and aluminum atoms and phosphorus atoms were added at 0.014 mol% and 0.028 mol%, respectively, relative to the acid component in the polyester. Except for that, the same operation as in the production of polyester pellet P-1 was performed. Polyester pellets (P-2) having an intrinsic viscosity of 0.65 dl/g were obtained.

(Polymerization of Urethane Resin A-1 Having Polycarbonate Structure)

To a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 32 parts by mass of 1,3-cyclohexyl diisocyanate, 7 parts by mass of dimethylolpropanoic acid, poly with a number average molecular weight of 800 58 parts by mass of hexamethylene carbonate diol, 3 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added, stirred for 3 hours at 75° C. under a nitrogen atmosphere, and the reaction solution reached a predetermined amine equivalent. Confirmed. Next, after the reaction liquid was cooled to 40°C, 5.17 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, the temperature was adjusted to 25°C, and the polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 2000 min ^-1 . Thereafter, a water-dispersible urethane resin solution (A-1) having a solid content of 34% was prepared by removing a part of acetone and water under reduced pressure.

(Polymerization of Urethane Resin A-2 Having Polycarbonate Structure)

To a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube and a thermometer, 38 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 9 parts by mass of dimethylolpropanoic acid, number average molecular weight 1000 53 parts by mass of polyhexamethylene carbonate diol and 84.00 parts by mass of acetone were added as a solvent, stirred for 3 hours at 75°C under a nitrogen atmosphere, and it was confirmed that the reaction solution had reached a predetermined amine equivalent weight. Next, after the reaction liquid was cooled to 40°C, 5.17 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, the temperature was adjusted to 25°C, and the polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 2000 min ^-1 . Thereafter, a water-dispersible urethane resin solution (A-2) having a solid content of 35% was prepared by removing a part of acetone and water under reduced pressure.

(Polymerization of Urethane Resin A-3 Having Polycarbonate Structure)

To a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 30 parts by mass of 4,4-dicyclohexylmethane diisocyanate and 16 parts by mass of polyethylene glycol monomethyl ether having a number average molecular weight of 700 50 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 1200, 4 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added, stirred under a nitrogen atmosphere at 75°C for 3 hours, and the reaction solution was It was confirmed that the desired amine equivalent weight was reached. Next, after the reaction solution was cooled to 40°C, a polyurethane prepolymer solution was obtained. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, the temperature was adjusted to 25°C, and the polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 2000 min ^-1 . Thereafter, a water-dispersible urethane resin solution (A-3) having a solid content of 35% was prepared by removing a part of acetone and water under reduced pressure.

(Polymerization of Urethane Resin A-4 Having Polycarbonate Structure)

To a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 24 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 4 parts by mass of dimethylolbutanoic acid, and a number average molecular weight of 2000 71 parts by mass of polyhexamethylene carbonate diol, 1 part by mass of neopentyl glycol, and 84.00 parts by mass of acetone were added as a solvent, stirred for 3 hours at 75 ° C. under a nitrogen atmosphere, the reaction solution reached a predetermined amine equivalent confirmed. Next, after this reaction liquid was cooled 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, the temperature was adjusted to 25°C, and the polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 2000 min ^-1 . Thereafter, a water-dispersible urethane resin solution (A-4) having a solid content of 34% by mass was prepared by removing a part of acetone and water under reduced pressure.

(Polymerization of Urethane Resin A-5 Not Containing Polycarbonate Polyol Component)

It was made to react in the temperature of 70-120 degreeC for 2 hours by the multistage isocyanate polyaddition method using diethylene glycol as a polyether polyol, organic polyisocyanate, and a chain extension agent. The obtained urethane prepolymer was mixed with an aqueous bisulfite solution, and the mixture was allowed to react while stirring well for about 1 hour to form a block. The reaction temperature was 60°C or less. Then, it was diluted with water to prepare a heat-reactive water-dispersible urethane resin solution (A-5) having a solid content of 20% by mass.

(Polymerization of Urethane Resin A-6 Having Polycarbonate Structure)

To a four-neck flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube and a thermometer, 54 parts by mass of 4,4-dicyclohexylmethane diisocyanate and 16 mass parts of polyethylene glycol monomethyl ether having a number average molecular weight of 700 18 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 1200, 12 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added, stirred for 3 hours at 75°C under a nitrogen atmosphere, and the reaction solution was It was confirmed that the desired amine equivalent weight was reached. Next, after this reaction liquid was cooled 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, the temperature was adjusted to 25°C, and the polyurethane prepolymer solution was added and dispersed in water while stirring and mixing at 2000 min ^-1 . Thereafter, a water-dispersible urethane resin solution (A-6) having a solid content of 34% by mass was prepared by removing a portion of acetone and water under reduced pressure.

Table 2 shows the following two items.

go. Mass ratio of polycarbonate polyol component and polyisocyanate component (polycarbonate polyol component/polyisocyanate component) when synthesizing and polymerizing the urethane resin forming the coating layer

me. Molecular Weight of Polycarbonate Polyol Component

(Polymerization of Block Isocyanate Crosslinking Agent B-1)

In a flask equipped with a stirrer, a thermometer and a reflux condenser, 66.04 parts by mass of a polyisocyanate compound having an isocyanurate structure made from hexamethylene diisocyanate (manufactured by Asahi Kasei Chemicals, Duranate TPA) 66.04 parts by mass, N-methylpyrrolidone 25.19 parts by mass of 3,5-dimethylpyrazole (dissociation temperature: 120°C, boiling point: 218°C) was added dropwise to 17.50 parts by mass, and maintained at 70°C in a nitrogen atmosphere for 1 hour. Then, 5.27 parts by mass of dimethylolpropanoic acid was added dropwise. After measuring the infrared spectrum of the reaction solution and confirming that the absorption of isocyanate groups has disappeared, 5.59 parts by mass of N,N-dimethylethanolamine and 132.5 parts by mass of water are added, and a block polyisocyanate aqueous dispersion having a solid content of 40% by mass (B- 1) was obtained. The number of functional groups of the block isocyanate crosslinking agent is 4.

(Polymerization of Block Isocyanate Crosslinking Agent B-2)

In a flask equipped with a stirrer, a thermometer and a reflux condenser, 100 parts by mass of a polyisocyanate compound having an isocyanurate structure using hexamethylene diisocyanate as a raw material (manufactured by Asahi Kasei Chemicals, Duranate TPA) 100 parts by mass, propylene glycol monomethyl ether acetate 55 parts by mass and 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) were introduced, and maintained at 70°C for 4 hours under a nitrogen atmosphere. After that, the temperature of the reaction solution was lowered to 50°C, and 47 parts by mass of methyl ethyl ketoxime was added dropwise. The infrared spectrum of the reaction solution was measured, it was confirmed that absorption of isocyanate groups had disappeared, and an oxime block isocyanate crosslinking agent (B-2) having a solid content of 40% by mass was obtained. The number of functional groups of the block isocyanate crosslinking agent is 3.

(Polymerization of carbodiimide B-3)

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

(Polymerization of polyester resin C-1)

194.2 parts by mass of dimethyl terephthalate, 184.5 parts by mass of dimethyl isophthalate, 14.8 parts by mass of dimethyl-5-sodium sulfoisophthalate, and 233.5 parts by mass of diethylene glycol were placed in a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser. part, 136.6 parts by mass of ethylene glycol and 0.2 part by mass of tetra-n-butyl titanate were introduced, and a transesterification reaction was performed at a temperature of 160°C to 220°C over 4 hours. Next, after raising the temperature to 255°C and gradually reducing the pressure of the reaction system, the mixture was reacted under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolymerized polyester resin (C-1). The obtained copolymerized polyester resin (C-1) was pale yellow and transparent. When the reduced viscosity of co-polyester resin (C-1) was measured, it was 0.70 dl/g. The glass transition temperature by DSC was 40°C.

(Preparation of polyester water dispersion)

15 parts by mass of polyester resin (C-1) and 15 parts by mass of ethylene glycol n-butyl ether were placed in a reactor equipped with a stirrer, a thermometer and a reflux device, and the mixture was heated and stirred at 110°C to dissolve the resin. After the resin was completely dissolved, 70 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 to prepare a milky white aqueous polyester dispersion (Cw-1) having a solid content of 15% by mass.

(Example 1)

(1) Preparation of coating liquid

The following coating agent is mixed with a mixed solvent of water and isopropanol, and the solid mass ratio of urethane resin solution (A-1) / crosslinking agent (B-1) / polyester water dispersion (Cw-1) is 25/26/49 A coating liquid was prepared.

Urethane resin solution (A-1) 3.55 parts by mass

Crosslinking agent (B-1) 3.16 parts by mass

Polyester aqueous dispersion (Cw-1) 16.05 parts by mass

particle 0.47 parts by mass

(Dry process silica with an average particle diameter of 200 nm, solid content concentration 3.5%)

particle 1.85 parts by mass

(silica sol having an average particle diameter of 40 to 50 nm, solid content concentration of 30% by mass)

Surfactants 0.30 parts by mass

(Silicone system, solid content concentration 10% by mass)

(2) Manufacture of easily adhesive polyester film

As a film raw material polymer, polyester pellets (P-1) were dried at 135°C for 6 hours under a reduced pressure of 133 Pa. After that, it was fed into an extruder, melt-extruded into a sheet at about 280°C, and quenched and adhered solidified on a rotating cooling metal roll maintained at a surface temperature of 20°C to obtain an unstretched PET sheet.

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

Subsequently, the coating solution left at room temperature for 5 hours or more was coated on one side of a PET film by a roll coating method, and then dried at 80°C for 20 seconds. In addition, the coating amount after final (after biaxial stretching) drying was adjusted to be 0.15 g/m 2 (application layer thickness after drying: 150 nm). Subsequently, the film was stretched 4.0 times in the width direction at 120 ° C. in a tenter, heated at 230 ° C. for 5 seconds while the length of the film was fixed in the width direction, and further, 3% widthwise relaxation treatment at 100 ° C. for 10 seconds was performed to obtain a 100 μm easily-adhesive polyester film.

(3) Manufacture of laminated polyester film for optics

(Laminate polyester film for optics (1) having a hard coat layer)

On the coating layer of the easy-adhesive polyester film, a coating liquid for forming a hard coat layer having the following composition was applied using a #5 wire bar, and dried at 80° C. for 1 minute to remove the solvent. Next, the film coated with the hard coat layer was irradiated with 300 mJ/cm 2 ultraviolet rays using a high-pressure mercury lamp, and a laminated polyester film for optics (1) having a hard coat layer was obtained.

(coating liquid for hard coat layer formation)

ㆍPentaerythritol triacrylate PETA 39.10% by mass

(Toagosei Co., Ltd., trifunctional acrylic UV-curable resin, solid content 100%, refractive index 1.49)

ㆍZirconia particles 3.40% by mass

(Nippon Shokubai, ZP-153, average particle diameter 11 nm, solid content 70%, refractive index 1.53)

ㆍPhotopolymerization initiator 3.50% by mass

(Omnirad184 by IGM Resins B.V.)

ㆍPhotopolymerization initiator 2.00% by mass

(Omnirad907 manufactured by IGM Resins B.V.)

ㆍSolvent 52.00% by mass

(methyl ethyl ketone (MEK)/propylene glycol monomethyl ether (PGM))

(Laminate polyester film for optics (2) having a hard coat layer)

On the coating layer of the easy-adhesive polyester film, a coating liquid for forming a hard coat layer having the following composition was applied using a #5 wire bar, and dried at 80° C. for 1 minute to remove the solvent. Next, the film coated with the hard coat layer was irradiated with 300 mJ/cm 2 ultraviolet rays using a high-pressure mercury lamp, and a laminated polyester film for optics (2) having a hard coat layer was obtained.

(coating liquid for hard coat layer formation)

ㆍPentaerythritol triacrylate PETA 34.2% by mass

(Toagosei Co., Ltd., trifunctional acrylic UV-curable resin, solid content 100%, refractive index 1.49)

ㆍNano Silica 4.30% by mass

(manufactured by Nissan Chemical Industries, Ltd., average particle size 80 nm, MEK-AC-5140Z, solid content 32%)

ㆍPhotopolymerization initiator 3.50% by mass

(Omnirad184 by IGM Resins B.V.)

ㆍPhotopolymerization initiator 2.00% by mass

(Omnirad907 manufactured by IGM Resins B.V.)

ㆍSolvent 56.00% by mass

(Propylene glycol monomethyl ether (PGM))

(Laminate polyester film for optics having a lens layer of photocurable urethane/acrylic resin)

On a SUS plate (SUS304) with a thickness of 1 mm kept clean, about 5 g of the following photocurable urethane/acrylic coating liquid was placed, and the coating layer surface of the easily adhesive polyester film and the photocurable urethane/acrylic coating liquid were overlapped so that they were in contact, The light-curing urethane/acrylic coating solution was compressed to stretch on a polyester film with a width of 10 cm and a diameter of 4 cm with a manually operated rubber roller. From the side of the easy-adhesive polyester film, a high-pressure mercury lamp was used to irradiate with ultraviolet rays of 300 mJ/cm 2 to cure the photocurable urethane/acrylic resin. A film sample having a photocurable urethane/acrylic layer having a thickness of 50 μm was peeled off from the SUS plate to obtain a laminated polyester film for optics having a photocurable urethane/acrylic layer (state before shaping).

(Light-curing urethane/acrylic coating liquid)

Light Curable Acrylic Resin 20.00% by mass

(Blemmer 650 by Shin Nakamura Kagaku)

Photocurable methacrylate resin 40.00% by mass

(BPE-500 manufactured by Shin Nakamura Kagaku)

Light-curing urethane/acrylic resin 29.00% by mass

(U-6HA manufactured by Shin Nakamura Kagaku)

Light Curable Acrylic Resin 8.00% by mass

(Shin Nakamura Kagaku AMP-10G)

photopolymerization initiator 3.00% by mass

(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Laminate polyester film for optics having lens layer of photocurable acrylic resin)

The photocurable urethane/acrylic coating liquid of the laminated polyester film for optical use having a photocurable urethane/acrylic layer is changed to the following photocurable acrylic coating liquid, and the amount of ultraviolet irradiation is changed to 100 mJ/cm 2 In the same way, the photocurable type A laminated polyester film for optics having an acrylic resin lens layer (state before shaping) was obtained.

(Photocuring acrylic coating liquid)

Light Curable Acrylic Resin 77.00% by mass

(A-BPE-4 manufactured by Shin Nakamura Kagaku)

Light Curable Acrylic Resin 22.00% by mass

(Shin Nakamura Kagaku AMP-10G)

photopolymerization initiator 1.00% by mass

(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Laminate polyester film for optics having a light diffusion layer)

On the coating layer of the easy-adhesive polyester film, a coating liquid for forming a light diffusion layer having the following composition was applied using a #5 wire bar, and dried and heat-cured at 160 ° C. for 60 seconds to obtain an optical laminated poly having a light diffusion layer. An ester film was obtained.

(Coating liquid for light diffusion layer formation)

Acrylic polyol (50% solid content) 150 parts by mass

(Acridic A-807: Dainippon Ink Gagaku High School)

Isocyanate (60% solid content) 30 parts by mass

(Takenate D11N: Takeda Yakuhin High School)

methyl ethyl ketone 200 parts by mass

butyl acetate 200 parts by mass

acrylic resin particles 40 parts by mass

(MX-1000, average particle diameter 10.0㎛: Soken Chemical)

(Laminated polyester film for optics having an anti-glare layer)

On the coating layer of the easy-adhesive polyester film, a coating liquid for forming an anti-glare layer having the following composition was applied using a #5 wire bar, and dried at 70° C. for 1 minute to remove the solvent. Subsequently, the film coated with the anti-glare layer was irradiated with ultraviolet rays of 300 mJ/cm 2 using a high-pressure mercury lamp to obtain a laminated polyester film for optics having an anti-glare layer having a thickness of 5 μm.

ㆍCoating liquid for forming anti-glare layer

toluene 34 mass parts

Pentaerythritol Triacrylate 50 parts by mass

Silica (average particle diameter 1㎛) 12 mass parts

Silicone (leveling agent) 1 part by mass

photopolymerization initiator 1 part by mass

(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Example 2)

Except having changed the urethane resin to (A-2), it carried out similarly to Example 1, and obtained the easily-adhesive polyester film and various laminated polyester films for optics.

(Example 3)

Except having changed the urethane resin to (A-3), it carried out similarly to Example 1, and obtained the easily-adhesive polyester film and various laminated polyester films for optics.

(Example 4)

Except having changed the crosslinking agent to (B-2), it carried out similarly to Example 1, and obtained the easily adhesive polyester film and the laminated polyester film for various optics.

(Example 5)

In a mixed solvent of water and isopropanol, the following coating agent was mixed, and the solid content mass ratio of urethane resin solution (A-1) / crosslinking agent (B-1) / polyester water dispersion (Cw-1) was 22/10/68 Except having changed, it carried out similarly to Example 1, and obtained the easily-adhesive polyester film and various laminated polyester films for optics.

Urethane resin solution (A-1) 2.71 parts by mass

Crosslinking agent (B-1) 1.00 parts by mass

Polyester Water Dispersion (Cw-1) 19.05 parts by mass

particle 0.47 parts by mass

(Dry process silica with an average particle diameter of 200 nm, solid content concentration 3.5%)

particle 1.85 parts by mass

(silica sol having an average particle diameter of 40 to 50 nm, solid content concentration of 30% by mass)

Surfactants 0.30 parts by mass

(Silicone system, solid content concentration 10% by mass)

(Example 6)

Except having changed the urethane resin to (A-2), it carried out similarly to Example 5, and obtained the easily-adhesive polyester film and various laminated polyester films for optics.

As shown in Table 5, in Examples 1 to 6, "B-A", "b", and "c-b" each satisfy the range of the following formula, and the haze, hard coat adhesion, and blocking resistance can be satisfied.

(i) 0.5≤B-A(at%)≤3.0

(ii) 30≤b(sec)≤180

(iii) 30 ≤ c-b (sec) ≤ 300

Moreover, "X" satisfies the following formula, and it was what could be satisfied in the adhesiveness to various optical function layers.

(iv) 2.0≤X(%)≤10.0

(Example 7)

As a film raw material polymer, except having changed the polyester pellet to (P-2), it carried out similarly to Example 1, and obtained the easily adhesive polyester film and various laminated polyester films for optics.

As shown in Table 5, in Example 7, "B-A", "b", and "c-b" each satisfy the range of the following formula, and the adhesion to various optical functional layers and blocking resistance can be satisfied.

(i) 0.5≤B-A(at%)≤3.0

(ii) 30≤b(sec)≤180

(iii) 30 ≤ c-b (sec) ≤ 300

In addition, "X" satisfies the following formula and was able to satisfy the adhesiveness to various optical function layers.

(iv) 2.0≤X(%)≤10.0

In addition, compared to Examples 1 to 6 using polyester pellet P-1, it was confirmed that the haze value was small and the transparency of the film improved.

(Example 8)

In order to vacuum-expose the easily-adhesive polyester film obtained in Example 1, the rewinding process was performed in the vacuum chamber. The pressure at this time was 0.002 Pa, and the exposure time was 10 minutes. In addition, the temperature of the center roll was 40 degreeC. Next, a transparent conductive thin film containing indium tin oxide was formed on the hard coat layer of the hard coat film. At this time, the pressure before sputtering was set to 0.0007 Pa, and DC power of 2 W/cm 2 was applied as a target using indium oxide containing 5% by mass of tin oxide (manufactured by Mitsui Kinzoku Kogyo, density 7.1 g/cm 3 ). Further, Ar gas was flowed at a flow rate of 130 sccm and O ₂ gas was flowed at a flow rate of 10 sccm, and a film was formed in an atmosphere of 0.4 Pa using a DC magnetron sputtering method. As described above, a transparent conductive film having a transparent conductive layer containing indium tin oxide having a thickness of 22 nm and having a surface resistance value of 250 Ω was obtained. It was what could be satisfied in the adhesiveness of a transparent conductive layer.

(Example 9)

In order to vacuum-expose the hard coat film (1) obtained in Example 1, the rewinding process was performed in the vacuum chamber. Subsequent steps were carried out in the same manner as in Example 8, whereby a transparent conductive film having a transparent conductive layer containing indium tin oxide having a thickness of 22 nm and having a surface resistance value of 250 Ω was obtained. It was what could be satisfied in the adhesiveness of a transparent conductive layer.

(Experimental Example 1)

In the same manner as in Example 1, except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content ratio of the urethane resin solution (A-5) / polyester aqueous dispersion (Cw-1) was changed to 29/71. Thus, easy-adhesive polyester films and laminated polyester films for various optics were obtained.

Urethane resin solution (A-5) 6.25 parts by mass

Polyester Water Dispersion (Cw-1) 20.00 parts by mass

Catalyst for Elastron 0.50 parts by mass

particle 1.02 parts by mass

(Dry process silica with an average particle diameter of 200 nm, solid content concentration 3.5%)

particle 2.15 parts by mass

(silica sol with average particle diameter of 40 nm, solid content concentration of 20% by mass)

Surfactants 0.30 parts by mass

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

As shown in Table 5, since "X" was less than 2.0% in Experimental Example 1, the adhesion to the lens layer was not satisfied. Moreover, since "b" exceeded 180 second, blocking resistance was not able to be satisfied either.

(Experimental Example 2)

Except having changed the urethane resin to (A-4), it carried out similarly to Example 1, and obtained the easily-adhesive polyester film and various laminated polyester films for optics.

(Experimental Example 3)

Except having changed the urethane resin to (A-4) and the crosslinking agent to (B-2), it was carried out similarly to Example 1, and the easily-adhesive polyester film and various laminated polyester films for optics were obtained.

As shown in Table 5, in Experimental Examples 2 and 3, since "B-A" was less than 0.5 at%, the hard coat adhesion was not completely satisfactory.

(Experimental Example 4)

Adhesion was carried out in the same manner as in Example 1 except that the following coating agent was mixed with a mixed solvent of water and isopropanol and the solid content ratio of the urethane resin solution (A-4)/crosslinking agent (B-1) was changed to 70/30. An easy polyester film and a laminated polyester film for optics were obtained.

Urethane resin solution (A-4) 9.03 parts by mass

Crosslinking agent (B-1) 3.38 mass parts

particle 0.52 parts by mass

(Dry process silica with an average particle diameter of 200 nm, solid content concentration 3.5%)

particle 1.80 parts by mass

(silica sol with average particle diameter of 40 nm, solid content concentration of 30% by mass)

Surfactants 0.30 parts by mass

(Silicone system, solid content concentration 10% by mass)

As shown in Table 5, in Experimental Example 4, since "c-b" exceeded 300 seconds, the haze was not satisfied.

(Experimental Example 5)

Adhesion was carried out in the same manner as in Example 1 except that the following coating agent was mixed with a mixed solvent of water and isopropanol, and the solid content ratio of the urethane resin solution (A-4)/crosslinking agent (B-1) was changed to 20/80. An easy polyester film and various laminated polyester films for optics were obtained.

Urethane resin solution (A-4) 2.58 parts by mass

Crosslinking agent (B-1) 9.00 parts by mass

particle 0.52 parts by mass

(Dry process silica with an average particle diameter of 200 nm, solid content concentration 3.5%)

particle 1.80 parts by mass

(silica sol with average particle diameter of 40 nm, solid content concentration of 30% by mass)

Surfactants 0.30 parts by mass

(Silicone system, solid content concentration 10% by mass)

As shown in Table 5, in Experimental Example 5, since "c-b" exceeded 300 seconds, the haze could not be satisfied.

(Experimental Example 6)

Except having changed the urethane resin to (A-2) and the crosslinking agent to (B-3), it carried out similarly to Example 5, and obtained the easily-adhesive polyester film and various laminated polyester films for optics.

As shown in Table 5, in Experimental Example 6, since "B-A" was less than 0.5 at%, blocking resistance and hard coat adhesion were not completely satisfactory.

(Experimental Example 7)

Except having changed the urethane resin to (A-6), it carried out similarly to Example 5, and obtained the easily-adhesive polyester film and the laminated polyester film for optics.

As shown in Table 5, in Experimental Example 7, since "X" was less than 2.0%, there were cases in which the adhesion to the lens layer was not completely satisfactory.

The evaluation method used in the present invention is described below.

(1) Haze

The haze of the obtained easily-adhesive polyester film was measured using a turbidity meter (Nippon Denshoku make, NDH5000) based on JIS K 7136:2000.

(2) Blocking resistance

Two film samples were stacked so that the coated layer faces faced each other, a load of 98 kPa was applied, and this was brought into close contact in an atmosphere of 50°C for 24 hours, and left to stand. Then, the film was peeled off, and the peeled state was judged according to the following criteria.

○: The coating layer can be peeled lightly without transition.

Δ: The coating layer is maintained, but the surface layer of the coating layer is partially transferred to the counter surface.

x: Two films adhered and could not be peeled off, or the film substrate was cleaved even after peeling.

(3) Adhesion

In the optical function layer of the laminated polyester film for optics thus obtained, 100 lattice-shaped cuts are made through the optical function layer to reach the base film using a cutter guide having a gap interval of 2 mm. Subsequently, cellophane adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) was affixed to the lattice-shaped cut surface, and rubbed with an eraser to adhere completely. After that, after performing the operation of vertically peeling the cellophane adhesive tape from the optical function layer surface of the laminated polyester film for optics 5 times, visually count the number of lattice images peeled from the optical function layer surface of the laminated polyester film for optics, The adhesiveness between the optical function layer and the film substrate is obtained from the following formula. In addition, among the lattice phases, those partially exfoliated are counted as separated lattice phases. Adhesion makes 95 (%) pass.

Adhesion (%) = (1 - number of peeled lattice phases/100) x 100

(4) Measurement of elemental distribution in the depth direction

Elemental distribution in the depth direction of the coating layer was measured by X-ray photoelectron spectroscopy (ESCA). As an ion source for etching, an Ar cluster that can be expected to have low damage to organic materials was used. In addition, the sample was rotated during etching to enable uniform etching. In order to minimize the damage caused by X-ray irradiation, spectrum collection at each etching time was performed in a snapshot mode enabling evaluation in a short time. In addition, for convenience of evaluation, spectrum collection was performed every 30 seconds until the etching time of 120 seconds and every 60 seconds thereafter. Details of measurement conditions are shown below. In the analysis, background removal was performed by the Shirley method.

ㆍDevice: K-Alpha ⁺ (manufactured by Thermo Fisher Scientific)

ㆍMeasurement conditions

Excitation X-rays: monochromated Al Kα rays

X-ray output: 12 kV, 2.5 mA

Photoelectron escape angle: 90°

Spot size: 200 μmφ

Pass energy: 150 eV (snapshot mode)

Acceleration voltage of ion gun: 6kV

Cluster Size: Large

Etching rate: 10 nm/min (converted to polystyrene)※

Sample Rotation During Etching: Yes

(For the calculation of the etching rate, monodisperse polystyrene having a molecular weight of Mn: 91000 (Mw/Mn = 1.05) was dissolved in toluene, and then a film thickness of 155 nm prepared on a silicon wafer by spin coating was used.)

Based on the data evaluated in this way, the abscissa represents the etching time from the coating layer surface, and the ratio of the amount of nitrogen atoms to the total amount of carbon atoms, oxygen atoms, nitrogen atoms, and silicon atoms (nitrogen atom ratio) is represented on the ordinate axis. Taken, a nitrogen distribution curve is drawn. The nitrogen distribution curves of the easily adhesive polyester film samples (Examples 2 and 5 and Experimental Example 6) are shown in FIGS. 1, 3 and 4, respectively. A method for obtaining the characteristic values of the present invention based on the nitrogen distribution curve of Example 2 shown in FIG. 1 will be explained using FIG. 2 . As shown in FIG. 2, the nitrogen atom ratio on the surface of the coating layer on the opposite side to the polyester film base material is A (at%), the maximum nitrogen atom ratio is B (at%), and the nitrogen atom ratio is the maximum value B (at%). The etching time to be b (sec), the etching time when the nitrogen atom ratio becomes 1/2B (at%) after b (sec) is read as c (sec), and B-A (at%), c-b (sec ) is obtained by calculating The nitrogen atom ratio on the surface of the coating layer on the opposite side to the polyester film base material refers to the nitrogen atom ratio at an etching time of 0 (seconds) in the figure (also described as "etching time s" on the horizontal axis in Figs. 1 to 4 The “s” in it means the unit “second”.)

(5) measurement of the OCOO bonding ratio of the surface area

The ratio (X) of OCOO bonds in the surface area was evaluated by X-ray photoelectron spectroscopy (ESCA). K-Alpha ⁺ (manufactured by Thermo Fisher Scientific) was used for the device. Details of measurement conditions are shown below. In addition, at the time of analysis, removal of the background was performed by the Shirley method. In addition, calculation of X was made into the average value of three or more measurement results.

ㆍMeasurement conditions

Excitation X-rays: monochromated Al Kα rays

X-ray output: 12 kV, 6 mA

Photoelectron escape angle: 90°

Spot size: 400 μmφ

Pass Energy: 50eV

Step: 0.1 eV

Energy resolution: FWHM=0.75eV of Ag3d(5/2) spectrum

5 and 6 are graphs showing analysis results of the C1s spectrum of the surface region of the easily adhesive polyester film of Example 6 and Experimental Example 1, respectively. The gray solid line represents the measured data of the C1s spectrum. The peak of the obtained measured spectrum was separated into a plurality of peaks, and the binding species corresponding to each peak were identified from the position and shape of each peak. Further, curve fitting was performed on the peaks derived from each binding species to calculate the peak area. Table 3 shows the binding species of each peak (1) to (6) that may appear.

The sum of peak areas derived from each bonded species in the C1s spectrum region refers to the sum of peak areas of peaks (1) to (6), and the peak area derived from OCOO bonds refers to the peak area of peak (5). When the sum of the peak areas derived from each binding species in the C1s spectrum region is 100%, X (%) represents the ratio of the area of peak (5) as a percentage (%).

Table 4 shows the peak area calculation results of peaks (1) to (6) in Example 6 and Experimental Example 1. As described above, the percentage data of peak (5) is the data of X (%). Peaks (3) and (6) of Example 6 and peaks (3) and (5) of Experimental Example 1 did not appear.

(6) Method for measuring number average molecular weight of polycarbonate polyol

When a urethane resin having a polycarbonate structure is measured by a proton nuclear magnetic resonance spectrum (1H-NMR), a peak derived from a methylene group adjacent to an OCOO bond is observed at around 4.1 ppm. In addition, a peak derived from a methylene group adjacent to a urethane bond formed in a reaction between polyisocyanate and polycarbonate polyol is observed at a high magnetic field of about 0.2 ppm from the peak. The number average molecular weight of the polycarbonate polyol was calculated from the integral of these two peaks and the molecular weight of the monomer constituting the polycarbonate polyol.

Table 5 summarizes the evaluation results of each Example and Experimental Example.

<Industrial Applicability>

The easy-adhesive polyester film in the present invention has excellent adhesion to a hard coat layer, a light diffusion layer, a lens layer, an anti-glare layer, and a transparent conductive layer, so it is particularly suitable for optical applications, and is mainly used for displays and the like. It is suitable as a base film of optical functional films, such as a coat film and a lens sheet using this film.

Claims (2)

An optical function of at least one layer selected from a hard coat layer, a light diffusion layer, a lens layer, an anti-glare layer, and a transparent conductive layer on the coating layer of an easily-adhesive polyester film having a coating layer on at least one surface of a polyester film base material. An optical laminated polyester film in which layers are laminated, wherein the coating layer is formed by curing a composition containing a urethane resin having a polycarbonate structure, a crosslinking agent, and a polyester resin, X-ray photoelectron spectroscopy for the coating layer In the distribution curve of the nitrogen element based on the element distribution measurement in the depth direction by, A (at%) is the nitrogen atom ratio on the surface of the coating layer on the opposite side to the polyester film substrate, and the maximum value of the nitrogen atom ratio is B (at %), the etching time at which the nitrogen atomic ratio shows the maximum value B (at%) is b (seconds), and the etching time when the nitrogen atomic ratio becomes 1/2B (at%) after b (seconds) is c (seconds) ), the sum of the peak areas derived from each binding species in the C1s spectrum region is 100 (%) in the surface analysis spectrum that satisfies the following formulas (i) to (iii) and is measured by X-ray photoelectron spectroscopy. ), and the laminated polyester film for optics that satisfies the following formula (iv) when the peak area derived from the OCOO bond is X (%).
(i) 0.5≤BA(at%)≤3.0
(ii) 30≤b(sec)≤180
(iii) 30 ≤ cb (sec) ≤ 300
(iv) 2.0≤X(%)≤10.0 The laminated polyester film for optics according to claim 1, wherein the haze of the easily-adhesive polyester film is 1.5 (%) or less.

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