JP4771021B2 - Easy-adhesive polyester film for optics - Google Patents

Description

  The present invention relates to an optically easy-adhesive polyester film having excellent adhesion and heat-and-moisture resistance. Specifically, it is suitable as a base material for optical functional films such as hard coat films, antireflection films, light diffusion sheets, lens sheets, near-infrared shielding films, transparent conductive films, and antiglare films, which are mainly used for displays and the like. The present invention relates to an optically easy-adhesive polyester film.

  In general, the base material of an optical functional film used as a member of a liquid crystal display (LCD) is a transparent thermoplastic made of polyethylene terephthalate (PET), acrylic, polycarbonate (PC), triacetyl cellulose (TAC), polyolefin, or the like. A resin film is used.

  When using the thermoplastic resin film as a base material for various optical functional films, functional layers corresponding to various applications are laminated. For example, in a liquid crystal display (LCD), a protective film (hard coat layer) that prevents scratches on the surface, an antireflection layer (AR layer) that prevents reflection of external light, and a prism layer that is used to collect and diffuse light And a functional layer such as a light diffusion layer for improving luminance. Among such substrates, particularly polyester films 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, in the case of a biaxially oriented thermoplastic film such as a biaxially oriented polyester film or a biaxially oriented polyamide film, the film surface is highly crystallized, so it has good adhesion to various paints, adhesives, inks, etc. There is a disadvantage of being scarce. For this reason, methods for imparting easy adhesion to the biaxially oriented polyester film surface by various methods have been proposed.

  For example, a method of providing easy adhesion to a base film by providing a coating layer mainly composed of various resins such as polyester, acrylic, polyurethane, and acrylic graft polyester on the surface of the base polyester film is generally used. Known. Among these coating methods, the polyester film before the completion of crystal orientation is coated on the base film with an aqueous coating solution containing the resin solution or a dispersion in which the resin is dispersed in a dispersion medium, and after drying, Stretch at least uniaxially, then heat treatment to complete the orientation of the polyester film (so-called in-line coating method), after the production of the polyester film, after applying a water-based or solvent-based coating liquid to the film, A drying method (so-called off-line coating method) is industrially implemented.

  A display such as an LCD or PDP, or a portable device using a hard coat film as a member is used in various environments regardless of indoors or outdoors. In particular, portable devices may require moisture and heat resistance that can withstand a bathroom, a hot and humid area, and the like. The optical functional film used for such applications is required to have high adhesion such that delamination does not occur even under high temperature and high humidity. Therefore, in the following patent document, a resin having a high glass transition temperature and a crosslinking agent are added to the coating liquid, and a hard coating layer is formed in the coating layer resin when the coating layer is formed by an in-line coating method, thereby imparting moisture and heat resistance. An easily adhesive polyester film is disclosed.

JP 2000-141574 A Japanese Patent No. 3900191 JP 2007-253512 A

  Longer life expectancy is expected for home appliances with a display to reduce the global environmental impact. Therefore, it was considered that the optical functional film used as a member also needs to maintain adhesiveness for a long time even under high temperature and high humidity. However, the easy-adhesion film as disclosed in the above-mentioned patent document shows good adhesion at first, but a decrease in adhesion strength is inevitable in long-term use under high temperature and high humidity. . Due to such a decrease in adhesion, there is a problem that the initial performance is not maintained for a long time.

  In addition, along with the refinement of optical design, various resin composition types having different refractive indices and strengths are being used as the photocurable resin constituting the optical functional layer. However, although the above-mentioned easy-adhesive film has high adhesion to a specific resin composition type, it is highly versatile and easy-to-adhere that exhibits the same degree of adhesion to various photocurable resins. There is a need for conductive films.

  In view of the above problems, the present invention hardly causes a decrease in adhesion under high temperature and high humidity, which has been considered to be unavoidable in the past, and has good adhesion to various optical resin compositions. An adhesive polyester film is provided.

  In the present invention, the adhesiveness under high temperature and high humidity refers to the use of a cutter guide having a clearance of 2 mm after laminating a photocurable resin layer and placing it in an environment of 80 ° C., 95% RH, 48 hours. Then, 100 grid-shaped cuts that penetrate the photocurable resin layer and reach the base film are made on the surface of the photocurable resin layer, and then a cellophane adhesive tape is applied to the grid-shaped cut surface and rubbed with an eraser. It means the adhesion when the same part is peeled off 5 times vigorously, and the adhesion is based on stricter criteria than the evaluation method described in JIS K5600-5-6, which is generally used. An object of the present invention is to exhibit an adhesiveness equivalent to the initial adhesiveness under such high temperature and high humidity.

As a result of diligent studies to solve the above problems, the present inventor is a polyester film having an application layer on at least one surface, and mainly comprises a urethane resin having an aliphatic polycarbonate polyol as a constituent component and a crosslinking agent, infrared aliphatic polycarbonate component derived from 1460 cm ^-1 vicinity of absorbance in the spectrum ratio of _{(a 1460)} and 1530 cm ^-1 near the absorbance derived from urethane component with _{(a 1530) (a 1460 /} a 1530) is 0. It has been found that the adhesion under high temperature and high humidity is improved by using a coating layer of 40 to 1.55, and the present invention has been achieved.

That is, the said subject can be achieved by the following solution means.
(1) A polyester film having a coating layer on at least one surface, wherein the coating layer is mainly composed of a urethane resin and a crosslinking agent having an aliphatic polycarbonate polyol as constituent components, and the urethane resin is an aliphatic polycarbonate diol. And a polyisocyanate and a chain extender as constituents, wherein the chain extender is an aliphatic diol having 4 to 10 carbon atoms or an aliphatic diamine having 4 to 10 carbon atoms, and infrared of the coating layer ratio of aliphatic polycarbonate component derived from 1460 cm ^-1 vicinity of absorbance in the spectrum _{(a 1460)} and 1530 cm ^-1 vicinity of absorbance from urethane component _{(a 1530) (a 1460 /} a 1530) is 0.40 An easily adhesive polyester film for optics, which is 1.55.
(2) The easy adhesion for optics, wherein the crosslinking agent is at least one crosslinking agent selected from a melamine crosslinking agent, an isocyanate crosslinking agent, a carbodiimide crosslinking agent, and an oxazoline crosslinking agent. Polyester film.
(3) The optical easy-adhesiveness, wherein a mass ratio of urethane resin and crosslinking agent (urethane resin / crosslinking agent) comprising aliphatic polycarbonate polyol as a constituent component in the coating layer is 1/9 to 9/1. Polyester film.
(4) The said easily adhesive polyester film for optics whose haze of a polyester film is 2.5% or less.
(5) The above-mentioned easily adhesive polyester film for optics, wherein the coating amount after drying of the coating layer is 0.02 to 0.5 g / m ² .
(6) The optically easily adhesive polyester film, wherein the urethane resin contains an aliphatic polycarbonate diol, a polyisocyanate, and a chain extender as components, and the number average molecular weight of the aliphatic polycarbonate diol is 1500 to 4000. .
(7) The said easily adhesive polyester film for optics in which the said urethane resin contains 3-60 mol% of polyol which has a carboxylic acid group or a carboxylate group as a structural component in all the polyisocyanates.
(8) The said easily adhesive polyester film for optics whose crow transition point temperature of the said urethane resin is less than 0 degreeC.
(9) The optically easy-adhesive polyester film, wherein the coating layer comprises a urethane resin having an aliphatic polycarbonate polyol as a constituent component, a crosslinking agent, particles, and a surfactant.
(10) The easily adhesive polyester film for optics, wherein the coating layer is formed by an in-line coating method.
(11) An optical function of at least one layer selected from a hard coat layer, a light diffusion layer, a lens layer, an electromagnetic wave absorption layer, a near-infrared shielding layer, and a transparent conductive layer on the coating layer of the easy-adhesive polyester film for optics. An optical laminated polyester film obtained by laminating layers.
(12) The optical laminated polyester film, wherein the optical functional layer is made of an acrylic curable resin.
(13) An optically easy-adhesive polyester film roll obtained by winding the optically easy-adhesive polyester film.

  The easily adhesive polyester film for optics of the present invention is excellent in adhesiveness (wet heat resistance) with various optical functional layers under high temperature and high humidity. Therefore, as a preferred embodiment, the adhesion at the high temperature and high humidity treatment is maintained at the same level as the initial adhesion.

(Polyester film)
The polyester resin constituting the substrate in the present invention includes polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polymethylene terephthalate, and copolymerization components such as diethylene glycol, neopentyl glycol, and polyalkylene glycol. A diol component, a polyester resin copolymerized with a dicarboxylic acid component such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, or 2,6-naphthalenedicarboxylic acid can be used.

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

  The biaxially stretched polyester film may be a single layer or a multilayer. Moreover, as long as it exists in the range with the effect of this invention, each of these layers can contain various additives in a polyester resin as needed. Examples of the additive include an antioxidant, a light resistance agent, an antigelling agent, an organic wetting agent, an antistatic agent, an ultraviolet absorber, and a surfactant.

  In addition, in order to improve handling properties such as slipperiness, rollability and blocking resistance of the film, and wear characteristics such as wear resistance and scratch resistance, inert particles may be included in the polyester film. However, since the film of the present invention is used as a base film for an optical member, it is required to have excellent handling properties while maintaining high transparency. Specifically, when used as a base film for an optical member, the total light transmittance of the optically easy-adhesive polyester film is preferably 85% or more, more preferably 87% or more, and 88% or more. More preferably, 89% or more is further more preferable, and 90% or more is particularly preferable.

  For high definition, the content of inert particles in the base film is preferably as small as possible. Therefore, it is a preferred embodiment that a multilayer structure in which particles are contained only in the surface layer of the film is used, or that the particles are substantially not contained in the film and fine particles are contained only in the coating layer.

  In particular, from the viewpoint of transparency, when an inert particle is practically not contained in the polyester film, an inorganic and / or heat-resistant polymer particle is contained in the aqueous coating solution in order to improve the handleability of the film. It is also preferable to form irregularities on the surface of the coating layer.

  Note that “substantially no inert particles” means, for example, in the case of inorganic particles, when the element derived from the particles is quantitatively analyzed by fluorescent X-ray analysis, 50 ppm or less, preferably 10 ppm or less, Preferably, the content is below the detection limit. This means that even if particles are not actively added to the base film, contaminants derived from foreign substances and raw material resin or dirt adhering to the line or equipment in the film manufacturing process will be peeled off and mixed into the film. It is because there is a case to do.

(Coating layer)
The easily adhesive polyester film for optics of the present invention is formed with a coating layer mainly composed of a urethane resin having an aliphatic polycarbonate polyol as a constituent component and a crosslinking agent, and the coating layer is measured by infrared spectroscopy. the ratio of the aliphatic polycarbonate component derived from 1460 cm ^-1 vicinity of absorbance _{(a 1460)} and 1530 cm ^-1 vicinity of absorbance from urethane component _{(a 1530) (a 1460 /} a 1530) is 0.40 to 1.55 It is important that Here, the “main component” means that it is contained in an amount of 50% by mass or more, more preferably 70% by mass or more as the total solid component contained in the coating layer.

  As in the above Patent Documents 1 to 3, in the conventional technical common sense, from the point of improving the heat-and-moisture resistance of the coating layer, a resin or a crosslinked structure having a high glass transition temperature is positively introduced in forming the coating layer, and a strong coating layer It was considered desirable. However, in the present invention, by combining a polyurethane resin and a crosslinking agent and controlling the absorbance by infrared spectroscopy within a certain range, a remarkable effect of improving adhesion under high temperature and high humidity heat was found, and the present invention It came. Although the mechanism of improving the adhesion under high temperature and high humidity with such a configuration is not well understood, the present inventor considers as follows.

  When an optical functional layer is laminated on a base film, strong stress is generated between the optical functional layer and the coating layer due to shrinkage during curing of the photocurable resin constituting the optical functional layer and swelling during high-temperature and high-humidity treatment. . When such a laminated film is placed under high temperature and high humidity, deterioration of the coating layer proceeds due to dissolution or swelling or hydrolysis by a solvent contained in the photocurable resin. As a result, it was considered that the above-mentioned stress could not be endured, the optical functional layer was peeled off, and the adhesion was lowered. Therefore, in order to maintain a high degree of adhesion under high temperature and high humidity, the coating layer should not only be firmly cross-linked or provided with hydrolysis resistance but also be flexible enough to withstand the above stress. Is considered desirable. However, simply having flexibility is problematic in terms of solvent resistance and strength. Therefore, it is most desirable to make these conflicting characteristics compatible.

In the present invention, the coating layer is mainly composed of a urethane resin having an aliphatic polycarbonate polyol as a constituent component and a cross-linking agent as a main component, and the coating layer is in the vicinity of 1460 cm ⁻¹ derived from an aliphatic polycarbonate component measured by infrared spectroscopy. _{By making} the ratio (A ₁₄₆₀ / A ₁₅₃₀ ) of the absorbance (A ₁₄₆₀ ) and the absorbance (A ₁₅₃₀ ) in the vicinity of 1530 cm ⁻¹ derived from the urethane component to be 0.40 to 1.55, the above characteristics are compatible. . That is, the above-mentioned characteristics can be achieved by coexisting a predetermined amount of an aliphatic polycarbonate component having hydrolysis resistance and flexibility and a urethane component exhibiting toughness while providing solvent resistance with a crosslinking agent. Is intended. Thereby, since the stress due to the shrinkage at the time of curing of the photocurable resin and the swelling due to the swelling at the time of high temperature and high humidity treatment can be relieved, it is possible to obtain good adhesion with various photocurable resins and the like. We believe that even under high-temperature and high-humidity environments, it is possible to prevent deterioration of the coating layer, such as dissolution, swelling, and hydrolysis due to the solvent and diluent monomer remaining in the coating layer.

Here, the absorbance in the vicinity of 1460 cm ⁻¹ (A ₁₄₆₀ ) is derived from the bending vibration specific to the CH bond of the methylene group contained in the aliphatic polycarbonate component. Therefore, the magnitude of the absorbance (A ₁₄₆₀ ) near 1460 cm ⁻¹ depends on the amount of the aliphatic polycarbonate polyol component constituting the urethane resin present in the coating layer. On the other hand, the absorbance (A ₁₅₃₀ ) in the vicinity of 1530 cm ⁻¹ is derived from the bending vibration specific to the N—H bond contained in the urethane component. Therefore, the magnitude of the absorbance (A ₁₅₃₀ ) near 1530 cm ⁻¹ depends on the amount of urethane components (number of urethane bonds) constituting the urethane resin present in the coating layer. Moreover, when using an isocyanate type crosslinking agent as a crosslinking agent, the magnitude | size of the light absorbency ( _A1530 ) vicinity of 1530cm < ^-1 > is the urethane component amount (urethane bond number) as the sum total of the urethane resin and crosslinking agent amount which exist in a coating layer. Depends on. Therefore, these absorbance ratios (A ₁₄₆₀ / A ₁₅₃₀ ) indicate that both components having different characteristics coexist in a specific ratio. In the present invention, the ratio (A ₁₄₆₀ / A ₁₅₃₀ ) is 0.40 to 1.55, but the lower limit of the ratio (A ₁₄₆₀ / A ₁₅₃₀ ) is preferably 0.45, more preferably 0.00. 50. The upper limit of the ratio (A ₁₄₆₀ / A ₁₅₃₀ ) is preferably 1.50, more preferably 1.40, still more preferably 1.30, and still more preferably 1.20. When the ratio (A ₁₄₆₀ / A ₁₅₃₀ ) is less than 0.40, the amount of the hard urethane component is excessive, and the stress relaxation of the coating layer is lowered, so that the heat and humidity resistance is lowered. Further, when the ratio (A ₁₄₆₀ / A ₁₅₃₀ ) exceeds 1.55, the aliphatic component of the flexible aliphatic polycarbonate is excessively increased, and the solvent resistance of the coating layer is lowered, so that the heat and humidity resistance is lowered. To do.

  According to the above aspect, the present invention can improve the adhesiveness (humidity heat resistance) with a lens layer and other optical functional layers under high temperature and high humidity. Further, the configuration of the present invention will be described in detail below.

(Urethane resin)
The urethane resin of the present invention includes at least a polyol component and a polyisocyanate component as constituent components, and further includes a chain extender as necessary. The urethane resin of the present invention is a polymer compound in which these constituent components are mainly copolymerized by urethane bonds. In this invention, it has an aliphatic polycarbonate polyol as a structural component of a urethane resin. Heat-and-moisture resistance can be improved by including a urethane resin containing an aliphatic polycarbonate as a constituent component in the coating layer of the present invention. The components of these urethane resins can be specified by nuclear magnetic resonance analysis or the like.

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

Examples of the aliphatic polycarbonate polyol include aliphatic polycarbonate diols and aliphatic polycarbonate triols, and aliphatic polycarbonate diols can be preferably used. Examples of the aliphatic polycarbonate diol that is a constituent component of the urethane resin of the present invention include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl- 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexane Aliphatic polycarbonate diols obtained by reacting one or more diols such as dimethanol with carbonates such as dimethyl carbonate, diphenyl carbonate, ethylene carbonate, and phosgene. It is below. The number average molecular weight of the aliphatic polycarbonate diol is preferably 1500 to 4000, and more preferably 2000 to 3000. When the number average molecular weight of the aliphatic polycarbonate diol is small, the ratio of the aliphatic polycarbonate component constituting the urethane resin is relatively small. Therefore, in order to make the ratio (A ₁₄₆₀ / A ₁₅₃₀ ) within the above range, it is preferable to control the number average molecular weight of the aliphatic polycarbonate diol within the above range. If the number average molecular weight of the aliphatic polycarbonate diol is large, the absorbance (A ₁₄₆₀ ) in the vicinity of 1460 cm ⁻¹ derived from the aliphatic polycarbonate component increases and the aliphatic component increases, so that the solvent resistance decreases. , The adhesion may be reduced. If the number average molecular weight of the aliphatic polycarbonate diol is small, a strong urethane component increases, and stress due to shrinkage or swelling of the photocurable resin or the like cannot be relieved, and adhesion may be lowered.

  Examples of the polyisocyanate that is a component of the urethane resin of the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate, and 1,3-bis (isocyanatomethyl) cyclohexane. Such as alicyclic diisocyanates such as hexamethylene diisocyanate and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate; Isocyanates. When aromatic isocyanate is used, there is a problem of yellowing, which may not be preferable for optical use requiring high transparency. Moreover, since it becomes a hard coating film compared with an aliphatic type | system | group, it becomes impossible to relieve | moderate the stress by shrinkage | contraction and swelling of photocurable resin etc., and adhesiveness may fall.

The ratio (A ₁₄₆₀ / A ₁₅₃₀ ) can also be adjusted by a chain extender. The present invention can be used. Chain extenders 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, ethylenediamine Diamines such as hexamethylenediamine and piperazine, aminoalcohols such as monoethanolamine and diethanolamine, thiodiglycols such as thiodiethylene glycol, and water. However, when a chain extender having a short main chain is used, the absorbance (A ₁₅₃₀ ) in the vicinity of 1530 cm ⁻¹ derived from the urethane component increases, and the flexibility of the coating layer may decrease. Therefore, a chain extender having a long main chain is preferable. Moreover, the point which provides the softness | flexibility of an application layer has preferable the chain extender of the diol and the diamine whose length of carbon number of a main chain is 4-10. From these points, 1,4-butanediol, 1,6-hexanediol, hexamethylenediamine and the like are preferable as the chain extender used in the present invention.

  The coating layer of the present invention is preferably provided by an in-line coating method described later using an aqueous coating solution. Therefore, it is desirable that the urethane resin of the present invention is water-soluble. The “water-soluble” means that it dissolves in water or an aqueous solution containing less than 50% by mass of a water-soluble organic solvent.

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

  In order to introduce a carboxylic acid (salt) group into a urethane resin, for example, as a polyol component, a polyol compound having a carboxylic acid group such as dimethylolpropionic acid or dimethylolbutanoic acid is introduced as a copolymer component to form a salt. Neutralize with an agent. Specific examples of the salt forming agent include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, tri-n-butylamine, N such as N-methylmorpholine and N-ethylmorpholine. -N-dialkylalkanolamines such as alkylmorpholines, N-dimethylethanolamine, N-diethylethanolamine and the like. These can be used alone or in combination of two or more.

  In order to impart water solubility, when a polyol compound having a carboxylic acid (salt) group is used as a copolymerization component, the composition molar ratio of the polyol compound having a carboxylic acid (salt) group in the urethane resin is the same as that of the urethane resin. When the total polyisocyanate component is 100 mol%, it is preferably 3 to 60 mol%, more preferably 5 to 40 mol%. If the composition molar ratio is less than 3 mol%, water dispersibility may be difficult. Moreover, when the said composition molar ratio exceeds 60 mol%, since water resistance falls, moist heat resistance may fall.

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

  The urethane resin is preferably contained in an amount of 10% by mass to 90% by mass with respect to the crosslinking agent. In particular, when high adhesion is required as in a lens layer, the content is more preferably 20% by mass or more and 80% by mass or less. When the content of the urethane resin is large, the adhesiveness under high temperature and high humidity is lowered, and conversely, when the content is small, the initial adhesiveness is lowered.

  In order to improve the solvent resistance of the urethane resin of the present invention, a self-crosslinking group may be introduced into the urethane resin itself in addition to the addition of a crosslinking agent. Thereby, the crosslinking degree of resin increases and solvent resistance improves. Although it does not specifically limit as a self-crosslinking group used for this invention, The comparatively stable silanol group can be used suitably also in aqueous | water-based coating liquid.

  A resin other than the urethane resin of the present invention may be contained in order to improve adhesion. For example, a urethane resin, an acrylic resin, a polyester resin, or the like containing polyether or polyester as a constituent component can be used.

(Crosslinking agent)
In the present invention, it is necessary to contain a crosslinking agent in the coating layer. By containing a crosslinking agent, it becomes possible to further improve the adhesion under high temperature and high humidity. As the crosslinking agent, those that react with a carboxylic acid group, a hydroxyl group, an amino group, etc. to form an amide bond, a urethane bond, or a urea bond are preferable because they are not easily deteriorated by high-temperature and high-humidity treatment. Conversely, when an ester bond or an ether bond is involved, it may be hydrolyzable, which is not preferable. Examples of the crosslinking agent suitably used in the present invention include melamine-based, isocyanate-based, carbodiimide-based, and oxazoline-based. Among these, an isocyanate type and a carbodiimide type are preferable from the viewpoint of the stability over time of the coating liquid and the effect of improving the adhesion under high temperature and high humidity treatment. Furthermore, it is particularly preferable to use an isocyanate-based crosslinking agent from the viewpoint that the coating layer has appropriate flexibility and suitably imparts the stress relaxation action of the coating layer. Moreover, in order to promote a crosslinking reaction, a catalyst etc. are used suitably as needed.

  As content of a crosslinking agent, 10 mass% or more and 90 mass% or less are preferable with respect to urethane resin. More preferably, it is 20 mass% or more and 80 mass% or less. When the amount is small, the solvent resistance of the coating layer is reduced, and the adhesiveness under high temperature and high humidity is reduced.When the amount is large, the flexibility of the resin of the coating layer is reduced, and at room temperature and high temperature and high humidity. The adhesiveness of is reduced.

  In the present invention, two kinds of crosslinking agents may be mixed in order to improve the coating film strength. Moreover, in order to promote a crosslinking reaction, a catalyst etc. are used suitably as needed.

(Additive)
In the present invention, particles may be contained in the coating layer. Particles are (1) silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, satin white, aluminum silicate, diatomaceous earth Inorganic particles such as soil, calcium silicate, aluminum hydroxide, hydrous halloysite, magnesium carbonate, magnesium hydroxide, (2) acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene / acrylic, styrene / Butadiene, polystyrene / acrylic, polystyrene / isoprene, polystyrene / isoprene, methyl methacrylate / butyl methacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol, di Rirufutareto systems include organic particles of polyester or the like.

  The particles preferably have an average particle size of 1 to 500 nm. Although an average particle diameter is not specifically limited, If it is 1-100 nm from the point which maintains the transparency of a film, it is preferable.

  The particles may contain two or more kinds of particles having different average particle diameters.

  In addition, said average particle diameter measures the maximum diameter of the 10 or more particle | grains which exist in the cross section of a coating layer by image | photographing the cross section of a laminated film at a magnification of 120,000 times using a transmission electron microscope (TEM). And can be obtained as an average value of them.

  As content of particle | grains, 0.5 mass% or more and 20 mass% or less are preferable. When the amount is small, sufficient blocking resistance cannot be obtained. Further, scratch resistance is deteriorated. When the amount is large, not only the transparency of the coating layer is deteriorated, but also the coating strength is lowered.

  The coating layer may contain a surfactant for the purpose of improving leveling properties during coating and defoaming the coating solution. The surfactant may be any of cationic, anionic and nonionic surfactants, but is preferably a silicon-based, acetylene glycol-based or fluorine-based surfactant. These surfactants are also preferably contained in a range that does not impair the adhesion to the optical functional layer, for example, in the range of 0.005 to 0.5% by mass in the coating solution.

  The optically easily adhesive polyester film of the present invention preferably has a haze value of 2.5% or less, more preferably 2.0% or less, and even more preferably 1.5% or less. In order to obtain high transparency, it is preferable to reduce the average particle size of the urethane resin. Thereby, the dispersibility and compatibility of the resin are improved, and high transparency is obtained. From the viewpoint of transparency, the average particle size of the urethane resin used in the coating layer is preferably 150 nm or less, and more preferably 100 nm or less.

  In order to impart other functionality to the coating layer, various additives may be contained within a range that does not impair the adhesion with the sealing material. Examples of the additive include fluorescent dyes, fluorescent brighteners, plasticizers, ultraviolet absorbers, pigment dispersants, foam suppressors, antifoaming agents, preservatives, and antistatic agents.

  In the present invention, examples of the method for providing the coating layer on the polyester film include a method in which a coating solution containing a solvent, particles and a resin is applied to the polyester film and dried. Examples of the solvent include organic solvents such as toluene, water, and a mixed system of water and a water-soluble organic solvent. Preferably, water alone or a mixture of a water-soluble organic solvent and water is used from the viewpoint of environmental problems. preferable.

(Manufacture of easily adhesive polyester film for optics)
The method for producing an optically easy-adhesive polyester film of the present invention will be described using a polyethylene terephthalate (hereinafter abbreviated as PET) film as an example, but is not limited to this.

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

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

  In an arbitrary stage of the film manufacturing process, a coating solution is applied to at least one surface of the PET film to form the coating layer. There is no particular problem even if the coating layer is formed on both sides of the PET film. The solid content concentration of the resin composition in the coating solution is preferably 2 to 35% by weight, particularly preferably 4 to 15% by weight.

  Any known method can be used as a method for applying the coating solution to the PET film. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. It is done. These methods are applied alone or in combination.

  In the present invention, the coating layer is formed by coating the coating solution on an unstretched or uniaxially stretched PET film, drying it, stretching in at least a uniaxial direction, and then performing a heat treatment.

In the present invention, the finally obtained coating layer preferably has a thickness of 20 to 350 nm, and the coating amount after drying is preferably 0.02 to 0.5 g / m ² . When the coating amount of the coating layer is less than 0.02 g / m ² , the effect on adhesiveness is almost lost. On the other hand, when the coating amount exceeds 0.5 g / m ² , haze increases.

  An optically easy-adhesive polyester film roll obtained by winding up the optically-adhesive polyester film of the present invention is also a preferred embodiment of the present invention. Since the coating layer of the present invention has good anti-blocking properties due to the addition of a crosslinking agent, it can be suitably used even when it is a roll for improving productivity.

  The thickness of the optically easy-adhesive polyester film of the present invention is not particularly limited, but can be arbitrarily determined in the range of 25 to 500 μm according to the specification of the application to be used. The upper limit of the thickness of the optically easy-adhesive polyester film is preferably 400 μm, and particularly preferably 350 μm. On the other hand, the lower limit of the film thickness is preferably 50 μm, particularly preferably 75 μm. If the film thickness is less than 25 μm, the mechanical strength tends to be insufficient. On the other hand, when the film thickness exceeds 500 μm, it tends to be difficult to wind it into a roll.

  When the easily adhesive polyester film for optics of the present invention is used as a roll, the winding length and width are appropriately determined depending on the use of the film roll. The winding length of the film roll is preferably 1500 m or more, more preferably 1800 m or more. The upper limit of the winding length is preferably 5000 m. Moreover, it is preferable that the width | variety of a film roll is 500 mm or more, More preferably, it is 800 mm. In addition, as an upper limit of the width | variety of a film roll, 2000 mm is preferable.

(Laminated film for optics)
The optically laminated polyester film of the present invention is selected from a hard coat layer, a light diffusion layer, a lens layer, an electromagnetic wave absorption layer, a near-infrared shielding layer, and a transparent conductive layer on at least one side of the above-mentioned polyester film coating layer. It is obtained by laminating at least one optical functional layer. The shape of the lens layer is not particularly limited. For example, a prism-shaped lens, a Fresnel-shaped lens, a microlens, or the like can be suitably applied.

  The material used for the optical functional layer is not particularly limited, and a resin compound that is polymerized and / or reacted by drying, heat, chemical reaction, or irradiation with an electron beam, radiation, or ultraviolet light is used. be able to. Examples of such a curable resin include melamine-based, acrylic-based, silicon-based, and polyvinyl alcohol-based curable resins. However, in terms of obtaining high surface hardness or optical design, a photocurable acrylic curable resin is used. Resins are preferred. As such an acrylic curable resin, a polyfunctional (meth) acrylate monomer or an acrylate oligomer can be used. Examples of the acrylate oligomer include polyester acrylate, epoxy acrylate, urethane acrylate, Examples include ether acrylate, polybutadiene acrylate, and silicone acrylate. A coating composition for forming the optical functional layer can be obtained by mixing a reactive diluent, a photopolymerization initiator, a sensitizer and the like with these acrylic curable resins.

  Moreover, the polyester film of this invention can obtain favorable adhesive strength other than the said optical use. Specifically, adhesion such as photographic photosensitive layer, diazo photosensitive layer, matte layer, magnetic layer, inkjet ink receiving layer, hard coat layer, UV curable resin, thermosetting resin, printing ink and UV ink, dry laminate, extrusion laminate, etc. Examples thereof include vacuum deposition, electron beam deposition, sputtering, ion plating, CVD, plasma polymerization and the like of an agent, a metal or an inorganic substance, or an oxide thereof, and an organic barrier layer.

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

(1) Intrinsic viscosity Based on JIS K7367-5, it measured at 30 degreeC, using the mixed solvent of phenol (60 mass%) and 1,1,2,2-tetrachloroethane (40 mass%) as a solvent.

(2) Glass transition temperature Based on JIS K7121, the glass transition start temperature was calculated | required from the DSC curve using the differential scanning calorimeter (The Seiko Instruments Inc. make, DSC6200).

(3) Absorbance measurement by infrared spectroscopy About the obtained optically-adhesive polyester film for optics, the coating layer was scraped off and about 1 mg of a sample was collected. A pressure was applied to the collected sample to prepare a coating layer sample piece (size: about 50 μm × about 50 μm) molded into a film having a thickness of about 1 μm. Further, a sample piece (blank sample piece) was prepared in the same manner as described above for a PET resin having the same quality as the base film as a blank sample.
The prepared sample piece was placed on a KBr plate, and an infrared absorption spectrum was measured by a microscopic transmission method under the following conditions. The infrared spectrum of the coating layer was determined as the difference spectrum between the infrared spectrum obtained from the coating layer sample piece and the spectrum of the blank sample piece.
Absorbance around 1460 cm ^-1 derived from an aliphatic polycarbonate component _{(A 1460)} is 1460 and the value of the absorption peak height having an absorption maximum in the region of ± 10 cm ^-1, the absorbance in the vicinity of 1530 cm ^-1 derived from urethane component (A ₁₅₃₀ ) is the value of the absorption peak height having an absorption maximum in the region of 1530 ± 10 cm ⁻¹ . The baseline was a line connecting the hems on both sides of each maximum absorption peak. The absorbance ratio was determined from the obtained absorbance by the following formula.
(Absorbance ratio) = A ₁₄₆₀ / A ₁₅₃₀

(Measurement condition)
Apparatus: FT-IR analyzer SPECTRA TECH IRμs / SIRM
Detector: MCT
Resolution: 4cm ^-1
Integration count: 128 times

(4) Total light transmittance of optically easy-adhesive polyester film The total light transmittance of the obtained optically-adhesive polyester film is based on JIS K 7105, and a turbidimeter (Nippon Denshoku, NDH2000) is used. And measured.

(5) Haze of optically easy-adhesive polyester film The haze of the obtained optically-adhesive polyester film was measured according to JIS K 7136 using a turbidimeter (Nippon Denshoku, NDH2000).

(6) Adhesiveness A cutter guide having a gap distance of 2 mm is provided on the surface of the optically laminated polyester film, the photocurable hard coat layer, the photocurable acrylic layer, or the photocurable urethane / acrylic layer (hereinafter referred to as an optical functional layer). Used to make 100 grid-like cuts that penetrate the optical functional layer and reach the base film. Next, a cellophane adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) was attached to the cut surface of the grid and rubbed with an eraser for complete adhesion. Then, after performing the work of peeling the cellophane adhesive tape perpendicularly from the optical functional layer surface of the laminated polyester film for optics 5 times, the number of squares peeled off from the optical functional layer surface of the laminated polyester film for optics was counted visually. The adhesiveness between the optical functional layer and the base film was determined from the formula: In addition, what peeled partially among squares was also counted as the square which peeled, and was ranked according to the following references | standards.
Adhesiveness (%) = (1−number of peeled squares / 100) × 100
A: 100% or material failure of the optical functional layer B: 99-90%
Δ: 89-70%
X: 69 to 0%

(7) Moisture and heat resistance The obtained laminated polyester film for optics was left in an environment of 80 ° C. and 95% RH for 48 hours in a high-temperature and high-humidity tank. Next, the laminated polyester film for optics was taken out and allowed to stand at room temperature and humidity for 12 hours. Thereafter, contact adhesion between the optical functional layer and the substrate film was determined by the same method as in (6) above, and ranked according to the following criteria.
A: 100% or material failure of the optical functional layer B: 99-90%
Δ: 89-70%
X: 69 to 0%

(Polymerization of urethane resin A-1 containing aliphatic polycarbonate polyol)
In a four-necked flask equipped with a stirrer, Dimroth cooler, nitrogen inlet tube, silica gel drying tube, and thermometer, 43.75 parts by mass of 4,4-diphenylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, several 153.41 parts by mass of polyhexamethylene carbonate diol having an average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent were added and stirred at 75 ° C. for 3 hours in a nitrogen atmosphere. It was confirmed that had reached the predetermined amine equivalent. Next, after the temperature of this reaction liquid was lowered 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 and adjusted to 25 ° C., while stirring and mixing at 2000 min ⁻¹ , the polyurethane prepolymer solution was added and dispersed in water. . Thereafter, a part of acetone and water was removed under reduced pressure to prepare a water-soluble polyurethane resin (A-1) having a solid content of 35%. The obtained polyurethane resin (A-1) had a glass transition temperature of -30 ° C.

(Polymerization of urethane resin A-2 containing aliphatic polycarbonate polyol)
In a four-necked flask equipped with a stirrer, a Dimroth cooler, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 29.14 parts by mass of 4,4-diphenylmethane diisocyanate, 7.57 parts by mass of dimethylolbutanoic acid, several An average molecular weight of 3000 polyhexamethylene carbonate diol 173.29 parts by mass, dibutyltin dilaurate 0.03 parts by mass, and 84.00 parts by mass of acetone as a solvent were added, and the mixture was stirred at 75 ° C. for 3 hours in a nitrogen atmosphere. It was confirmed that had reached the predetermined amine equivalent. Next, after the temperature of this reaction liquid was lowered 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 and adjusted to 25 ° C., while stirring and mixing at 2000 min ⁻¹ , the polyurethane prepolymer solution was added and dispersed in water. . Thereafter, a part of acetone and water was removed under reduced pressure to prepare a water-soluble polyurethane resin (A-2) having a solid content of 35%.

(Polymerization of urethane resin A-3 containing aliphatic polycarbonate polyol as a constituent)
In a four-necked flask equipped with a stirrer, Dimroth cooler, nitrogen inlet tube, silica gel drying tube, and thermometer, 43.75 parts by mass of 4,4-diphenylmethane diisocyanate, 11.12 parts by mass of dimethylolbutanoic acid, hexane 1.97 parts by mass of diol, 143.40 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent were added, and 75 ° C. in a nitrogen atmosphere. The mixture was stirred for 3 hours to confirm that the reaction solution reached a predetermined amine equivalent. Next, after the temperature of this reaction liquid was lowered 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 and adjusted to 25 ° C., while stirring and mixing at 2000 min ⁻¹ , the polyurethane prepolymer solution was added and dispersed in water. . Thereafter, a part of acetone and water was removed under reduced pressure to prepare a water-soluble polyurethane resin (A-3) having a solid content of 35%.

(Polymerization of silanol group-containing urethane resin A-4 containing aliphatic polycarbonate polyol as a constituent)
In a four-necked flask equipped with a stirrer, a Dimroth cooler, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 38.41 parts by mass of isophorone diisocyanate, 6.95 parts by mass of dimethylolpropanoic acid, and a number average molecular weight of 2000 Polyhexamethylene carbonate diol 158.999 parts by mass, dibutyltin dilaurate 0.03 parts by mass, and acetone 84.00 parts by mass as a solvent were added and stirred at 75 ° C. for 3 hours in a nitrogen atmosphere. It was confirmed that the equivalent amount was reached. Next, after cooling this reaction liquid to 40 degreeC, 4.37 mass parts of triethylamine was added, and the polyurethane prepolymer solution was obtained. Next, 3.84 parts by mass of γ- (aminoethyl) aminopropyltriethoxysilane, 1.80 parts by mass of 2-[(2-aminoethyl) amino] ethanol and 450 g of water were added, and the polyurethane prepolymer solution was dropped. And dispersed in water. Thereafter, a part of acetone and water was removed under reduced pressure to prepare a water-soluble silanol group-containing polyurethane resin (A-4) having a solid content of 30%.

(Polymerization of urethane resin A-5 containing aliphatic polycarbonate polyol as a constituent)
A water-soluble polyurethane resin having a solid content of 35% was obtained in the same manner except that the polyhexamethylene carbonate diol having a number average molecular weight of 2000 in the water-soluble polyurethane resin (A-1) was changed to a polyhexamethylene carbonate diol having a number average molecular weight of 1000. (A-5) was obtained.

(Polymerization of urethane resin A-6 containing aliphatic polycarbonate polyol as a constituent)
A water-soluble polyurethane resin having a solid content of 35% was obtained in the same manner except that the polyhexamethylene carbonate diol having a number average molecular weight of 2000 in the water-soluble polyurethane resin (A-1) was changed to a polyhexamethylene carbonate diol having a number average molecular weight of 5000. (A-6) was obtained.

(Polymerization A-7 of Polyurethane Resin Containing Polyester Polyol)
The water-soluble polyurethane resin (A-) having a solid content of 35% was prepared in the same manner except that the polyhexamethylene carbonate diol having a number average molecular weight of 2000 of the water-soluble polyurethane resin (A-1) was changed to a polyester diol having a number average molecular weight of 2000. 7) was obtained.

(Polymerization A-8 of Polyurethane Resin Containing Polyether Polyol)
A water-soluble polyurethane resin (A) having a solid content of 35% was obtained in the same manner except that the polyhexamethylene carbonate diol having a number average molecular weight of 2000 in the water-soluble polyurethane resin (A-1) was changed to a polyether diol having a number average molecular weight of 2000. -8) was obtained.

(Polymerization of block polyisocyanate crosslinking agent)
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) in a flask equipped with a stirrer, a thermometer and a reflux condenser, 55 parts by mass of propylene glycol monomethyl ether acetate, 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) was charged and held at 70 ° C. for 4 hours in a nitrogen atmosphere. Thereafter, the reaction solution temperature 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 to confirm that the absorption of the isocyanate group had disappeared, and a block polyisocyanate aqueous dispersion (B) having a solid content of 75% by mass was obtained.

(Polymerization of oxazoline crosslinking agent)
A mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropanol as an aqueous medium in a flask equipped with a thermometer, a nitrogen gas introduction tube, a reflux condenser, a dropping funnel, and a stirrer, and a polymerization initiator (2, 2 4 parts by mass of '-azobis (2-amidinopropane) dihydrochloride) was added. On the other hand, in a dropping funnel, 16 parts by mass of 2-isopropenyl-2-oxazoline as a polymerizable unsaturated monomer having an oxazoline group, methoxypolyethylene glycol acrylate (average number of moles of ethylene glycol added: 9 moles, Shin Nakamura Chemical) A mixture of 32 parts by mass and 32 parts by mass of methyl methacrylate was added and added dropwise at 70 ° C. over 1 hour in a nitrogen atmosphere. After completion of dropping, the reaction solution was stirred for 9 hours and cooled to obtain a water-soluble resin (C) having an oxazoline group with a solid content concentration of 40% by mass.

(Polymerization of carbodiimide crosslinking agent)
A flask equipped with a stirrer, thermometer and reflux condenser was charged with 168 parts by mass of hexamethylene diisocyanate and 220 parts by mass of polyethylene glycol monomethyl ether (M400, average molecular weight 400), stirred at 120 ° C. for 1 hour, 26 parts by mass of 4′-dicyclohexylmethane diisocyanate and 3.8 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide (2% by weight based on the total isocyanate) were added as a carbodiimidization catalyst, and 185 under a nitrogen stream. Stir at 5 ° C. for a further 5 hours. The infrared spectrum of the reaction solution was measured, and it was confirmed that absorption at a wavelength of 2200 to 2300 cm ⁻¹ disappeared. It stood to cool to 60 degreeC, 567 mass parts of ion-exchange water was added, and the carbodiimide water-soluble resin (D) of 40 mass% of solid content was obtained.

Example 1
(1) Adjustment of coating liquid The following coating agent was mixed and the coating liquid was created.
Water 55.62% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 11.29 mass%
Block polyisocyanate aqueous dispersion (B) 2.26% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

(2) Production of optically easy-adhesive polyester film As a film raw material polymer, PET resin pellets having an intrinsic viscosity of 0.62 dl / g and substantially free of particles are obtained at 135 ° C. under a reduced pressure of 133 Pa. Dry for hours. Thereafter, the sheet was supplied to an extruder, melted and extruded into a sheet at about 280 ° C., and rapidly cooled and 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 to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a difference in peripheral speed to obtain a uniaxially stretched PET film.

Subsequently, after apply | coating the said coating liquid on the single side | surface of PET film by the roll coat method, it dried at 80 degreeC for 20 second. The final coating amount (after biaxial stretching) was adjusted so that the coating amount after drying was 0.15 g / m ² . Subsequently, the film was stretched 4.0 times in the width direction at 120 ° C. with a tenter, and heated at 230 ° C. for 0.5 seconds with the length in the width direction fixed, and further at 230 ° C. for 10 seconds. % Relaxation treatment in the width direction was performed. Both ends were trimmed, wound up by a winding device, further divided into two in the width direction and slitted to obtain a film roll having a width of 1300 mm, a film length of 3000 m, and a film thickness of 100 μm. Table 1 shows the evaluation results for the obtained optically easy-adhesive polyester film.

(3) Production of optical laminated polyester film (Optical laminated polyester film having a hard coat layer)
The coating liquid for forming a hard coat layer (E) having the following composition was applied to the coating layer surface of the optically easy-adhesive polyester film using a # 10 wire bar and dried at 70 ° 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 to obtain an optical laminated polyester film having a hard coat layer having a thickness of 5 μm.
Hard coat layer forming coating solution (E)
Methyl ethyl ketone 65.00% by mass
Dipentaerythritol hexaacrylate 27.20% by mass
(Shin-Nakamura Chemical A-DPH)
Polyethylene diacrylate 6.80% by mass
(Shin-Nakamura Chemical A-400)
Photopolymerization initiator 1.00% by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Optical laminated polyester film with photocurable urethane / acrylic layer)
About 5 g of the following photo-curing acrylic coating liquid is placed on a 1 mm thick SUS plate (SUS304) kept clean, and the film is applied so that the coating layer surface of the film sample and the photo-curing acrylic coating liquid are in contact with each other. The photo-curing urethane / acrylic coating solution (F) was pressure-bonded with a manually loaded rubber roller having a width of 10 cm and a diameter of 4 cm from above the sample. Next, from the film surface side, UV light of 500 mJ / cm ² was irradiated using a high pressure mercury lamp to cure the photocurable urethane / acrylic resin. A film sample having a photocurable urethane / acrylic layer having a thickness of 20 μm was peeled from the SUS plate to obtain a laminated polyester film for optics.
Light curable urethane / acrylic coating solution (F)
Photo-curing acrylic resin 67.00% by mass
(Shin-Nakamura Chemical A-BPE-4)
Photo-curing acrylic resin 15.00% by mass
(AMP-10G manufactured by Shin-Nakamura Chemical)
Light curable urethane / acrylic resin 15.00% by mass
(Shin Nakamura Chemical U-6HA)
Photopolymerization initiator 3.00% by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Laminated polyester film for optics having a photocurable acrylic layer)
Optical lamination in the same manner except that the photocurable urethane / acrylic coating liquid (F) of the optically laminated polyester film having the photocurable urethane / acrylic layer is changed to the photocurable acrylic coating liquid (G). A polyester film was obtained.
Photo-curing acrylic coating solution (G)
Photo-curing acrylic resin 67.00% by mass
(Shin-Nakamura Chemical A-BPE-4)
Photo-curing acrylic resin 30.00% by mass
(AMP-10G manufactured by Shin-Nakamura Chemical)
Photopolymerization initiator 3.00% by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

Comparative Example 1
An optically easily adhesive polyester film and an optically laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to the polyurethane resin (A-5).

Comparative Example 2
An optically easily adhesive polyester film and an optical laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to the polyurethane resin (A-6).

Comparative Example 3
An optically easily adhesive polyester film and an optical laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to the polyurethane resin (A-7).

Comparative Example 4
An optically easy-adhesive polyester film and an optical laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to the polyurethane resin (A-8).

Comparative Example 5
Except having changed the coating liquid into the following, it carried out similarly to Example 1, and obtained the easily adhesive polyester film for optics, and the laminated polyester film for optics.
Water 53.04 mass%
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 16.13 mass%
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 2
Except having changed the coating liquid into the following, it carried out similarly to Example 1, and obtained the easily adhesive polyester film for optics, and the laminated polyester film for optics.
Water 53.91% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 14.51% by mass
Block polyisocyanate aqueous dispersion (B) 0.75% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 3
Except having changed the coating liquid into the following, it carried out similarly to Example 1, and obtained the easily adhesive polyester film for optics, and the laminated polyester film for optics.
Water 54.76% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 12.90 mass%
Block polyisocyanate aqueous dispersion (B) 1.51% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 4
Except having changed the coating liquid into the following, it carried out similarly to Example 1, and obtained the easily adhesive polyester film for optics, and the laminated polyester film for optics.
Water 57.35% by mass
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 8.06% by mass
Block polyisocyanate aqueous dispersion (B) 3.76% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 5
Except having changed the coating liquid into the following, it carried out similarly to Example 1, and obtained the easily adhesive polyester film for optics, and the laminated polyester film for optics.
59.92% by mass of water
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 3.23 mass%
Block polyisocyanate aqueous dispersion (B) 6.02 mass%
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 6
Except having changed the coating liquid into the following, it carried out similarly to Example 1, and obtained the easily adhesive polyester film for optics, and the laminated polyester film for optics.
60.79% by mass of water
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 1.61% by mass
Block polyisocyanate aqueous dispersion (B) 6.77% by mass
Particles 0.71% by mass
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.07% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.05% by mass
(Silicon, solid content concentration of 100% by mass)

Example 7
An optically easily adhesive polyester film and an optical laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to the polyurethane resin (A-2).

Example 8
An optically easily adhesive polyester film and an optical laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to the polyurethane resin (A-3).

Example 9
An optically easily adhesive polyester film and an optically laminated polyester film were obtained in the same manner as in Example 1 except that the polyurethane resin was changed to a silanol group-containing polyurethane resin (A-4).

Example 10
An optical laminated polyester film was obtained in the same manner as in Example 1 except that the block polyisocyanate aqueous dispersion (B) was changed to a water-soluble resin (C) having an oxazoline group.

Example 11
The laminated polyester film for optics was obtained like Example 1 except having changed the block polyisocyanate water dispersion (C) into the carbodiimide water-soluble resin (D).

Example 12
An optical laminated polyester film was obtained in the same manner as in Example 1 except that the block polyisocyanate aqueous dispersion (C) was changed to imino / methylolmelamine (solid content concentration: 70% by mass).

Example 13
Except having changed the coating liquid into the following, it carried out similarly to Example 1, and obtained the easily adhesive polyester film for optics, and the laminated polyester film for optics.
62.82% by mass of water
Isopropanol 30.00% by mass
Polyurethane resin (A-1) 5.64% by mass
Block polyisocyanate aqueous dispersion (B) 1.13% by mass
0.35% by mass of particles
(Silica sol with an average particle size of 40 nm, solid content concentration of 40% by mass)
0.04% by mass of particles
(Silica sol with an average particle size of 450 nm, solid content concentration of 40% by mass)
Surfactant 0.02% by mass
(Silicon, solid content concentration of 100% by mass)

  The easily adhesive polyester film for optics of the present invention is excellent in adhesion with an optical functional layer and adhesion under high temperature and high humidity (moisture and heat resistance). Therefore, a hard coat film mainly used for displays and the like is used. It is suitable as a base film for optical functional films such as antireflection films, light diffusion sheets, lens sheets, near-infrared shielding films, transparent conductive films, and antiglare films.

Claims (10)

A polyester film having a coating layer on at least one side,
The coating layer is mainly composed of a urethane resin and a cross-linking agent having aliphatic polycarbonate polyol as constituent components,
The urethane resin contains an aliphatic polycarbonate diol, polyisocyanate, and a chain extender as components, and the chain extender is an aliphatic diol having 4 to 10 carbon atoms or an aliphatic diamine having 4 to 10 carbon atoms. And
The ratio (A ₁₄₆₀ / A ₁₅₃₀ ) of the absorbance (A ₁₄₆₀ ) near 1460 cm ⁻¹ derived from the aliphatic polycarbonate component and the absorbance (A ₁₅₃₀ ) near 1530 cm ⁻¹ derived from the urethane component in the infrared spectrum of the coating layer. ) Is 0.40 to 1.55, an easily adhesive polyester film for optics.   2. The optical ease according to claim 1, wherein the cross-linking agent is at least one cross-linking agent selected from a melamine cross-linking agent, an isocyanate cross-linking agent, a carbodiimide cross-linking agent, and an oxazoline cross-linking agent. Adhesive polyester film.   The optical according to claim 1 or 2, wherein a mass ratio of urethane resin and crosslinking agent (urethane resin / crosslinking agent) comprising aliphatic polycarbonate polyol as a constituent component in the coating layer is 1/9 to 9/1. Easy-adhesive polyester film.   The easily adhesive polyester film for optics according to any one of claims 1 to 3, wherein the haze of the polyester film is 2.5% or less. The dried coating amount of the coating layer is 0.02 to 0.5 g / ^{m 2,} optical highly adhesive polyester film according to claim 1.   The easily adhesive polyester film for optics according to any one of claims 1 to 5, wherein the coating layer is composed of a urethane resin having an aliphatic polycarbonate polyol as a constituent component, a crosslinking agent, particles, and a surfactant.   The easily adhesive polyester film for optics according to any one of claims 1 to 6, wherein the coating layer is formed by an in-line coating method.   The hard-coat layer, the light diffusing layer, the lens layer, the electromagnetic wave absorbing layer, the near-infrared blocking layer, and the transparent conductive layer are selected as the coating layer of the optically easy-adhesive polyester film according to claim 1. An optically laminated polyester film obtained by laminating at least one optical functional layer.   The laminated polyester film for optics according to claim 8, wherein the optical functional layer is made of an acrylic cured resin.   An easily-adhesive polyester film roll for optical use obtained by winding up the easily-adhesive polyester film for optical use according to any one of claims 1 to 7.