JP6323520B2 - Polarizer - Google Patents

Description

The present invention relates to a polarizing plate, in a polarizing plate manufacturing process, fewer fish eyes, excellent in mechanical strength and heat resistance, are bonded to facilitate the polarizing film, more easily peeled off during the process The present invention relates to a polarizing plate manufacturing process film, which relates to a polarizing plate using a film used for protecting the polarizing film from being improved in handling properties and protecting the polarizing film from defects such as scratches. .

  Conventionally, when transporting, storing and processing resin plates, metal plates, glass plates, etc., preventing scratches and dirt, and scratching when processing components used in electronic fields such as liquid crystal panels and polarizing plates Wide range of surface protection films for applications such as prevention of dust and dirt, prevention of dirt and dirt during transportation and storage of automobiles, protection of automobile coating from acid rain, and protection during plating and etching of flexible printed circuit boards It is used.

  These surface protective films have an appropriate bonding force to the adherends when transporting, storing or processing various adherends such as resin plates, metal plates and glass plates. However, by adhering to the surface of the adherend, the surface of the adherend is required to be protected and easily peeled off after the end of the purpose. In order to overcome these problems, proposals have been made to use polyolefin-based films for surface protection (Patent Documents 1 and 2).

  Especially for the polarizing plate manufacturing process, a self-adhesive polyethylene film is used as a protective film for a polarizing film when it is bonded to the opposite side of the polarizing film adhesive layer in order to improve handling properties (patent Document 3), and may be bonded to protect the surface opposite to the surface provided with the protective film through the adhesive layer of the polarizing film from scratches (Patent Documents 4 and 5).

  However, since a polyolefin-based film is used as the protective film base material, it is not possible to remove defects caused by gel-like materials and deteriorated materials, which are commonly referred to as fisheye, resulting from the film base material. When the polarizing film is inspected in a state where the protective film is bonded, there is a problem that it becomes an obstacle such as detecting a defect of the protective film.

  In addition, as the base material of the protective film, a film having a certain degree of mechanical strength is required so that the base material is not stretched due to various processing tensions such as bonding with a polarizing film. Polyolefin films generally have inferior mechanical strength, and are disadvantageous in that they are unsuitable for high-tension processing due to an increase in processing speed in order to emphasize productivity.

  Furthermore, even when the processing temperature is increased to improve the processing speed and various characteristics, the polyolefin-based film is not excellent in shrinkage stability due to heat, so that the dimensional stability is poor. Therefore, there is a demand for a film that has little thermal deformation even when processed at high temperature and has excellent dimensional stability.

JP-A-5-98219 JP 2007-270005 A JP 2010-197820 A JP 2009-181042 A JP 2011-197282 A

The present invention has been made in view of the above circumstances, and the problem to be solved is that, during the polarizing plate manufacturing process, there are few fish eyes, excellent mechanical strength and heat resistance, and can be easily bonded to a polarizing film, Furthermore, it is a film for a polarizing plate manufacturing process that is easily peeled off during the process, and is used for improving the handling property of the polarizing film and protecting the polarizing film from defects such as scratches. It is providing the polarizing plate which uses the polyester film for manufacturing processes.

  As a result of intensive studies in view of the above circumstances, the present inventor has found that the use of a laminated polyester film having a specific configuration can easily solve the above-described problems, and has completed the present invention.

That is, the gist of the present invention, the feature that the at least one surface of the polyester film, thickness have a coating layer is in the range of 0.01 to 10 [mu] m, made by bonding the coating layer and the polarizing film The present invention resides in a method for producing a polarizing plate, wherein a coating layer is formed by in-line coating on at least one surface of a polarizing plate and a polyester film, and a polarizing film is bonded to the coating layer .

The polarizing plate of the present invention has few fish eyes as a protective film during the manufacturing process of the polarizing plate, is excellent in mechanical strength and heat resistance, is easily bonded to the polarizing film, and is easily peeled off during the process. It is a film that can be used , and its industrial value is high.

  We think that it is necessary to change the base material of the base film significantly in order to reduce fish eyes, improve mechanical strength, and improve heat resistance, and as a result of various studies, they differ greatly from conventional polyolefin-based materials. It has been found that this can be achieved by using a polyester-based material. However, by greatly changing the material system of the base film, the bonding characteristics are greatly reduced, and cannot be achieved with a general polyester film.

  Therefore, we considered giving the bonding properties by laminating the coating layer, but in offline coating performed after the polyester film manufacturing process, heat is applied during the coating and drying process, so the dimensions of the finished film change. In addition, there is a disadvantage that it increases the risk of scratches and foreign matter adhesion due to the addition of one additional coating process, and also leads to an increase in manufacturing cost. The method was considered and considered. Hereinafter, the details of the present invention will be described.

  The polyester film constituting the laminated polyester film in the present invention may have a single layer structure or a multilayer structure, and may have four or more layers as long as it does not exceed the gist of the present invention other than a two-layer or three-layer structure. It may be a multilayer, and is not particularly limited. It is preferable to have a multi-layer structure of two or more layers and to give each layer a characteristic so as to achieve multiple functions.

  The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Typical polyester includes polyethylene terephthalate and the like. On the other hand, the dicarboxylic acid component of the copolyester includes isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxybenzoic acid, etc.), etc. 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexane dimethanol, neopentyl glycol, is mentioned.

  From the viewpoint of forming a film that can withstand various processing conditions, it is preferable that the mechanical strength and heat resistance (dimensional stability by heating) are high, and for that purpose, it is preferable that the copolymer polyester component is small. Specifically, the proportion of the monomer forming the copolyester in the polyester film is preferably in the range of 10 mol% or less, more preferably 5 mol% or less, and more preferably produced as a by-product during homopolyester polymerization. It is a grade which contains the diether component of 3 mol% or less which is a grade which will carry out. In view of mechanical strength and heat resistance, a more preferable form of polyester is more preferably a film formed from polyethylene terephthalate or polyethylene naphthalate, which is polymerized from terephthalic acid and ethylene glycol, among the above compounds. In view of ease of handling and handling properties as a protective film, a film formed from polyethylene terephthalate is more preferable.

  There is no restriction | limiting in particular as a polymerization catalyst of polyester, A conventionally well-known compound can be used, For example, an antimony compound, a titanium compound, a germanium compound, a manganese compound, an aluminum compound, a magnesium compound, a calcium compound etc. are mentioned. Among these, antimony compounds are preferable because they are inexpensive, and titanium compounds and germanium compounds have high catalytic activity, can be polymerized in a small amount, and the amount of metal remaining in the film is small. This is also preferable from the viewpoint of increasing the transparency and reducing the amount of foreign matter because metal aggregation is reduced. Furthermore, since a germanium compound is expensive, it is more preferable to use a titanium compound.

  In the case of polyester using a titanium compound, the titanium element content is preferably 50 ppm or less, more preferably 1 to 20 ppm, and still more preferably 2 to 10 ppm. If the content of the titanium compound is too high, the polyester may be deteriorated in the process of melt-extruding the polyester, resulting in a strong yellowish film. If the content is too low, the polymerization efficiency is poor and the cost is low. In some cases, a film having a sufficient strength or a sufficient strength cannot be obtained. Moreover, when using the polyester by a titanium compound, it is preferable to use a phosphorus compound in order to reduce the activity of a titanium compound for the purpose of suppressing deterioration in the step of melt extrusion. As the phosphorus compound, orthophosphoric acid is preferable in view of the productivity and thermal stability of the polyester. The phosphorus element content is preferably in the range of 1 to 300 ppm, more preferably 3 to 200 ppm, and still more preferably 5 to 100 ppm with respect to the amount of polyester to be melt-extruded. If the content of the phosphorus compound is too large, it may cause gelation or foreign matter. If the content is too small, the activity of the titanium compound cannot be lowered sufficiently, and the yellowish It may be a film.

  In the polyester layer of the film of the present invention, particles can be blended for the purpose of imparting slipperiness, preventing scratches in each step, and improving anti-blocking properties. When the particles are blended, the kind of the particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness, and specific examples thereof include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, sulfuric acid. Examples thereof include inorganic particles such as calcium, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, zirconium oxide, and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, and benzoguanamine resin. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used. Of these, silica particles and calcium carbonate particles are preferable because they are particularly effective in a small amount.

  The average particle diameter of the particles is preferably 10 μm or less, more preferably in the range of 0.01 to 5.0 μm. When the average particle diameter exceeds 10 μm, there may be a concern about problems due to dropout of particles or reduction in transparency of the film.

Further, the content of the particles in the polyester layer is unclear because there is a balance with the average particle size of the particles, but is preferably 5% by weight or less, more preferably in the range of 0.0003 to 3% by weight, and still more preferably. Is in the range of 0.0005 to 1% by weight. When the particle content exceeds 5% by weight, there may be a concern about problems due to dropout of particles or reduction in transparency of the film.
When there are no or few particles, the transparency of the film becomes high and the film becomes a good film, but the slipperiness may be insufficient. There are cases where improvement is required.

The shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc.
These series of particles may be used in combination of two or more as required.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage for producing the polyester constituting each layer, but it is preferably added after completion of esterification or transesterification.

  In the polyester film of the present invention, conventionally known ultraviolet absorbers, antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added as necessary in addition to the above-described particles. .

  The thickness of the polyester film in the present invention is not particularly limited as long as it can be formed into a film, but is preferably 2 to 350 μm, more preferably 5 to 200 μm, and still more preferably 10 to 80 μm. is there.

  As a film forming method of the film of the present invention, a generally known film forming method can be adopted, and there is no particular limitation. For example, when producing a biaxially stretched polyester film, the polyester raw material described above is first melt-extruded from a die using an extruder, and the molten sheet is cooled and solidified with a cooling roll to obtain an unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method or a liquid application adhesion method is preferably employed. Next, the obtained unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, the film is stretched in the direction perpendicular to the first-stage stretching direction at usually 70 to 170 ° C. and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, a method of obtaining a biaxially oriented film by performing heat treatment at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% can be mentioned. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  In the present invention, the simultaneous biaxial stretching method can be adopted for the production of the polyester film constituting the laminated polyester film. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is usually stretched and oriented in the machine direction and the width direction at a temperature controlled normally at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear driving method can be employed.

  Next, formation of the coating layer which comprises the laminated polyester film in this invention is demonstrated. The coating layer of the present invention is laminated on a polyester film and formed by in-line coating.

  In-line coating is a method of coating within the process of manufacturing a polyester film, and specifically, a method of coating at any stage from melt extrusion of a polyester to heat setting after stretching and winding up. Usually, it is preferable to coat on either an unstretched sheet obtained by melting and quenching, or a stretched uniaxially stretched film.

  Although not limited to the following, for example, in sequential biaxial stretching, a method of stretching in the transverse direction after coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) is particularly excellent. According to such a method, film formation and coating layer formation can be performed at the same time, so there is an advantage in manufacturing cost. In addition, in order to perform stretching after coating, the thickness of the coating layer can be changed by the stretching ratio. Compared to offline coating, thin film coating can be performed more easily.

  Further, by providing the coating layer on the film before stretching, the coating layer can be stretched together with the base film, whereby the coating layer can be firmly adhered to the base film. Furthermore, in the production of a biaxially stretched polyester film, the film can be restrained in the longitudinal and lateral directions by stretching while gripping the film end with a clip, etc. High temperature can be applied while maintaining the properties. Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer can be improved, and the coating layer and the base film can be more firmly adhered to each other. Furthermore, a strong coating layer can be obtained.

  According to the above-mentioned process by in-line coating, the film size does not change greatly depending on whether or not the coating layer is formed, and the risk of scratches and foreign matter adhesion does not change greatly depending on whether or not the coating layer is formed. This is a significant advantage over an extra off-line coating. Furthermore, as a result of various studies, it has been found that in-line coating has an advantage that transfer of the coating layer to the polarizing film can be reduced. This is because heat treatment can be performed at a high temperature that cannot be obtained by off-line coating, and the coating layer and the substrate film are considered to be a result of tighter adhesion.

  In the present invention, it is an essential requirement to have a coating layer formed by in-line coating. The said coating layer is provided in order to bond directly to a polarizing film.

  For the formation of the coating layer used for laminating with the polarizing film, it is preferable to use a compound having a low glass transition point so that the laminating is easier. The preferred range of the glass transition point depends on the compound used, but is generally preferably 0 ° C. or lower, more preferably −10 ° C. or lower, and further preferably −20 ° C. or lower. Moreover, when the peeling characteristic with a polarizing film is considered, the preferable range of a minimum is -80 degreeC. Furthermore, in order to stabilize the bonding characteristics, it is preferable that the amount of the release agent such as a silicone compound used is small in the formation of the coating layer, and the ratio in the coating layer is preferably 10% by weight or less, more It is preferably 5% by weight or less, and more preferably not used for forming the coating layer.

  The compound having a low glass transition point is not a low-molecular compound but a high-molecular compound in order to reduce the transfer of the coating layer of the present invention to the polarizing film after bonding and peeling to the polarizing film. Is preferred.

As the polymer compound having a glass transition point of 0 ° C. or lower, a conventionally known polymer compound can be used. Specific examples thereof include polyester resin, acrylic resin, urethane resin, polyvinyl resin (polyvinyl alcohol, vinyl chloride acetic acid). Vinyl copolymers, etc.), among them, polyester resin, acrylic resin, and urethane resin are preferable in consideration of bonding characteristics and applicability. Furthermore, in consideration of stronger bonding characteristics and reusability of the film, a polyester resin or an acrylic resin is preferable, and adhesion of the base material polyester film or transfer of the coating layer to the polarizing film is preferable. The polyester resin is most preferable when the amount is small, and the acrylic resin is most preferable when the blocking property with the back surface side is considered.

  The polyester resin includes, for example, those composed of the following polyvalent carboxylic acid and polyvalent hydroxy compound as main constituent components. That is, as the polyvalent carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and 2,6 -Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid monopotassium salt and ester-forming derivatives thereof can be used. As the polyvalent hydroxy compound, ethylene Recall, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol , Neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol Polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like can be used. One or more compounds may be appropriately selected from these compounds, and a polyester resin may be synthesized by a conventional polycondensation reaction.

  Among them, it is preferable to contain an aliphatic polyvalent carboxylic acid or an aliphatic polyvalent hydroxy compound as a constituent component in order to lower the glass transition point to 0 ° C. or lower. In general, since a polyester resin is composed of an aromatic polyvalent carboxylic acid and a polyvalent hydroxy compound including an aliphatic group, in order to lower the glass transition point than a general polyester resin, an aliphatic polyvalent compound is used. It is effective to contain a carboxylic acid. From the viewpoint of lowering the glass transition point, the aliphatic polyvalent carboxylic acid should have a long carbon number, preferably 6 or more (adipic acid), more preferably 8 or more, and still more preferably 10 or more. The upper limit of the preferred range is 20.

  Further, from the viewpoint of improving the bonding properties, the content of the aliphatic polyvalent carboxylic acid in the acid component in the polyester resin is preferably 2 mol% or more, more preferably 4 mol% or more, and even more preferably 6 mol. % Or more, particularly preferably 10 mol% or more, and the upper limit of the preferred range is 50 mol%.

  In the aliphatic polyvalent hydroxy compound, in order to lower the glass transition point, the number of carbon atoms is preferably 4 or more (butanediol), and the content of the hydroxy component in the polyester resin is preferably 10 mol. % Or more, more preferably in the range of 30 mol% or more.

  In view of suitability for in-line coating, it is preferable to use an aqueous system. For this reason, it is preferable that a sulfonic acid, a sulfonic acid metal salt, a carboxylic acid, and a carboxylic acid metal salt are contained in the polyester resin. In view of good dispersibility in water, sulfonic acid and sulfonic acid metal salt are preferable, and sulfonic acid metal salt is particularly preferable.

  When using the sulfonic acid, sulfonic acid metal salt, carboxylic acid, or carboxylic acid metal salt, the content of the acid component in the polyester resin is preferably 0.1 to 10 mol%, more preferably 0.2 to It is in the range of 8 mol%. By using in the above range, water dispersibility is good.

  In addition, considering the appearance of coating in in-line coating, adhesion to polyester film and blocking, and reduction of transfer of the coating layer to the polarizing film when used as a protective film, as an acid component in the polyester resin, to some extent It is preferable to contain the aromatic polyvalent carboxylic acid. Among aromatic polycarboxylic acids, a benzene ring structure such as terephthalic acid or isophthalic acid is more preferable than a naphthalene ring structure from the viewpoint of bonding characteristics. Furthermore, in order to further improve the bonding characteristics, it is more preferable to use two or more kinds of aromatic polyvalent carboxylic acids in combination.

  The glass transition point of the polyester resin for improving the bonding properties is preferably 0 ° C. or lower, more preferably −10 ° C. or lower, and further preferably −20 ° C. or lower. The lower limit of the preferred range is − 60 ° C. It becomes easy to set it as the film which has the optimal bonding characteristic and peeling characteristic by using in the said range.

The acrylic resin is a polymer composed of a polymerizable monomer including acrylic and methacrylic monomers (hereinafter, acrylic and methacryl may be abbreviated as (meth) acryl). These may be either homopolymers or copolymers, and copolymers with polymerizable monomers other than acrylic and methacrylic monomers.

  Moreover, the copolymer of these polymers and other polymers (for example, polyester, polyurethane, etc.) is also included. For example, a block copolymer or a graft copolymer. Alternatively, a polymer (possibly a mixture of polymers) obtained by polymerizing a polymerizable monomer in a polyester solution or a polyester dispersion is also included. Similarly, a polymer obtained by polymerizing a polymerizable monomer in a polyurethane solution or a polyurethane dispersion (sometimes a mixture of polymers) is also included. Similarly, a polymer (in some cases, a polymer mixture) obtained by polymerizing a polymerizable monomer in another polymer solution or dispersion is also included.

  The polymerizable monomer is not particularly limited, but particularly representative compounds include, for example, various carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Monomers, and salts thereof; such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxyl fumarate, monobutyl hydroxy itaconate Various hydroxyl group-containing monomers; various such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate No (meta) acrylic Acid esters; various nitrogen-containing compounds such as (meth) acrylamide, diacetone acrylamide, N-methylolacrylamide or (meth) acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene Various vinyl esters such as vinyl propionate and vinyl acetate; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane; phosphorus-containing vinyl monomers; Examples include various vinyl halides such as vinyl and biliden chloride; and various conjugated dienes such as butadiene.

  In order to lower the glass transition point to 0 ° C. or lower, it is necessary to use a (meth) acrylic system having a glass transition point of the homopolymer of 0 ° C. or lower. For example, ethyl acrylate (glass transition point: −22 ° C.), n-propyl acrylate (glass transition point: −37 ° C.), isopropyl acrylate (glass transition point: −5 ° C.), normal butyl acrylate (glass transition point: −55 ° C.), n-hexyl acrylate (glass transition point: − 57 ° C), 2-ethylhexyl acrylate (glass transition point: -70 ° C), isononyl acrylate (glass transition point: -82 ° C), lauryl methacrylate (glass transition point: -65 ° C), 2-hydroxyethyl Examples include acrylate (glass transition point: −15 ° C.).

  From the viewpoint of bonding properties, the monomer content of the acrylic resin as the monomer constituting the acrylic resin is preferably 30% by weight or more, more preferably, as a proportion of the total acrylic resin, as a percentage of the glass transition point of the homopolymer. The range is 45% by weight or more, more preferably 60% by weight or more, and particularly preferably 70% by weight or more. The upper limit of the preferred range is 99% by weight. By using in this range, good bonding characteristics can be easily obtained.

  Moreover, as a glass transition point of the monomer whose homopolymer has a glass transition point of 0 ° C. or lower for improving the bonding properties, it is preferably −20 ° C. or lower, more preferably −30 ° C. or lower, and further preferably −40 ° C. Hereinafter, it is particularly preferably −50 ° C. or lower, and the lower limit of the preferred range is −100 ° C. It becomes easy to set it as the film which has a suitable bonding characteristic by using in the said range.

  The monomer used for improving the bonding properties is preferably an alkyl (meta) having an alkyl group having 4 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, and even more preferably 4 to 12 carbon atoms. ) Acrylate. Acrylic resins containing normal butyl acrylate and 2-ethylhexyl acrylate are optimal from the viewpoint of mass production industrially and handling and supply stability.

  As a further optimal form of the acrylic resin for improving the bonding properties, the total content of normal butyl acrylate and 2-ethylhexyl acrylate in the acrylic resin is preferably 30% by weight or more, more preferably 40%. The upper limit of the preferred range is 99% by weight, more preferably 50% by weight or more.

The glass transition point of the acrylic resin for improving the bonding characteristics is preferably 0 ° C. or less, more preferably −10 ° C. or less, still more preferably −20 ° C. or less, and particularly preferably −30 ° C. or less. The lower limit of the preferred range is −80 ° C. It becomes easy to set it as the film which has the optimal bonding characteristic and peeling characteristic by using in the said range.

  The urethane resin is a polymer compound having a urethane bond in the molecule, and is usually produced by a reaction between a polyol and an isocyanate. Examples of the polyol include polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

  Polycarbonate polyols are obtained from a polyhydric alcohol and a carbonate compound by a dealcoholization reaction. Examples of the polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane. Diol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decane Diol, neopentyl glycol, 3-methyl-1,5-pentanediol, 3,3-dimethylol heptane and the like can be mentioned. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of polycarbonate polyols obtained from these reactions include poly (1,6-hexylene) carbonate, poly (3- And methyl-1,5-pentylene) carbonate.

  From the viewpoint of improving the bonding properties, the carbon chain of the chain alkyl chain is preferably 4 to 30, more preferably 4 to 20, and even more preferably 6 to 12 in a polycarbonate polyol composed of a diol component. Yes, in terms of industrial mass production and good handling and supply stability, 1,6-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol It is optimal that it is a copolymerized polycarbonate polyol containing at least two kinds of diols selected from among the above.

  Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

  From the viewpoint of improving the bonding properties, the monomer forming the polyether is an aliphatic diol, particularly a straight chain, preferably having 2 to 30, more preferably 3 to 20, and still more preferably 4 to 12 carbon atoms. It is a polyether polyol containing an aliphatic diol.

  Polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides. Product and polyhydric alcohol (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol 2-methyl-2-propyl-1 3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexane Diol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamine, lactone diol, etc.) and those having derivative units of lactone compounds such as polycaprolactone.

  Considering the bonding characteristics, among the above polyols, polycarbonate polyols and polyether polyols are more preferably used, and polycarbonate polyols are particularly preferable.

  Examples of the polyisocyanate compound used for obtaining the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, α ′. -Aliphatic diisocyanates having aromatic rings such as tetramethylxylylene diisocyanate, aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Methanzi Cyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination.

  A chain extender may be used when synthesizing the urethane resin, and the chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group. Alternatively, a chain extender having two amino groups can be mainly used.

  Examples of the chain extender having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, and esters such as neopentyl glycol hydroxypivalate. And glycols such as glycols. Examples of the chain extender having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3- Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- Aliphatic diamines such as decane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isoprobilitincyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, 1 , 3-Bisaminomethylcyclohexa And alicyclic diamines such as

  The urethane resin in the present invention may use a solvent as a medium, but preferably uses water as a medium. In order to disperse or dissolve the urethane resin in water, there are a forced emulsification type using an emulsifier, a self-emulsification type in which a hydrophilic group is introduced into the urethane resin, and a water-soluble type. In particular, the self-emulsification type in which an ionic group is introduced into the structure of the urethane resin to form an ionomer is preferable because of excellent storage stability of the liquid and water resistance and transparency of the resulting coating layer.

  Examples of the ionic group to be introduced include various groups such as a carboxyl group, sulfonic acid, phosphoric acid, phosphonic acid, and quaternary ammonium salt, and a carboxyl group is preferred. As a method for introducing a carboxyl group into a urethane resin, various methods can be taken in each stage of the polymerization reaction. For example, there are a method of using a carboxyl group-containing resin as a copolymer component during prepolymer synthesis, and a method of using a component having a carboxyl group as one component such as polyol, polyisocyanate, and chain extender. In particular, a method in which a desired amount of carboxyl groups is introduced using a carboxyl group-containing diol depending on the amount of this component charged is preferred.

For example, dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid and the like are copolymerized with a diol used for polymerization of a urethane resin. Can do. The carboxyl group is preferably in the form of a salt neutralized with ammonia, amine, alkali metal, inorganic alkali or the like. Particularly preferred are ammonia, trimethylamine and triethylamine.
In such a urethane resin, the carboxyl group from which the neutralizing agent has been removed in the drying step after coating can be used as a crosslinking reaction point by another crosslinking agent. Thereby, it is possible to further improve the durability, solvent resistance, water resistance, blocking resistance, and the like of the obtained coating layer, as well as excellent stability in a liquid state before coating.

  The glass transition point of the urethane resin for improving the bonding properties is preferably 0 ° C. or less, more preferably −10 ° C. or less, further preferably −20 ° C. or less, and particularly preferably −30 ° C. or less. The lower limit of the preferred range is −80 ° C. It becomes easy to set it as the film which has the optimal bonding characteristic and peeling characteristic by using in the said range.

  Moreover, it is also possible to use a crosslinking agent in combination for adjusting the strength of the coating layer, the bonding characteristics, and the peeling characteristics. A conventionally well-known material can be used with a crosslinking agent, For example, an epoxy compound, a melamine compound, an oxazoline compound, an isocyanate type compound, a carbodiimide type compound, a silane coupling compound, a hydrazide compound, an aziridine compound etc. are mentioned. From the viewpoint of the strength of the coating layer and the adjustment of the bonding properties, an epoxy compound, a melamine compound, an oxazoline compound, an isocyanate compound, a carbodiimide compound, and a silane coupling compound are preferable, and an epoxy compound is particularly preferable.

  When a crosslinking agent other than an epoxy compound is used, if the content in the coating layer is too large, the bonding characteristics may be deteriorated too much. Therefore, when using a crosslinking agent other than an epoxy compound, it is necessary to pay attention to the content in the coating layer.

  The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include condensates of epichlorohydrin with ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A and the like hydroxyl groups and amino groups, There are polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane. Examples of the polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, poly Examples of tetramethylene glycol diglycidyl ether and monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N′-tetraglycidyl-m-xylyl. Examples include range amine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

  Among the above, polyether epoxy compounds are preferable from the viewpoint of good bonding characteristics. The amount of the epoxy group is preferably a polyepoxy compound that is trifunctional or more polyfunctional than bifunctional.

  The melamine compound is a compound having a melamine skeleton in the compound. For example, an alkylolized melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and these Mixtures can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Moreover, as a melamine compound, either a monomer or a multimer more than a dimer may be sufficient, or a mixture thereof may be used. In view of reactivity with various compounds, it is preferable that the melamine compound contains a hydroxyl group. Further, a product obtained by co-condensing urea or the like with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

  The oxazoline compound is a compound having an oxazoline group in the molecule, and a polymer containing an oxazoline group is particularly preferable, and can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide, N-alkyl ( (Meth) acrylamide, N, N-dialkyl (meth) acrylamide, As the alkyl group, unsaturated amides such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group and cyclohexyl group); vinyl acetate , Vinyl esters such as vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride And α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like, and one or more of these monomers can be used.

  The amount of the oxazoline group of the oxazoline compound is preferably in the range of 0.5 to 10 mmol / g, more preferably 1 to 9 mmol / g, still more preferably 3 to 8 mmol / g, and particularly preferably 4 to 6 mmol / g. By using in the said range, durability of a coating film improves and it becomes easy to adjust a bonding characteristic.

  The isocyanate compound is a compound having an isocyanate derivative structure typified by isocyanate or blocked isocyanate. Examples of the isocyanate include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate, and aromatic rings such as α, α, α ′, α′-tetramethylxylylene diisocyanate. Aliphatic isocyanates such as aliphatic isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate Ne Alicyclic isocyanates such as bets are exemplified. Further, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays.

  When used in the state of blocked isocyanate, the blocking agent includes, for example, bisulfites, phenolic compounds such as phenol, cresol, and ethylphenol, and alcohols such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol. Compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, methyl isobutanoyl acetate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan, dodecyl mercaptan, ε-caprolactam, δ-valerolactam, etc. Lactam compounds, amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, Examples include oxime compounds such as maldehyde, acetoald oxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more.

  In addition, the isocyanate compound in the present invention may be used alone, or may be used as a mixture or bond with various polymers. In the sense of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or a bond with a polyester resin or a urethane resin.

  The carbodiimide-based compound is a compound having a carbodiimide structure, and is used for improving the wet heat resistance of the coating layer. The carbodiimide compound is a compound having one or more carbodiimide or carbodiimide derivative structures in the molecule, but a polycarbodiimide compound having two or more in the molecule is more preferable for better adhesion and the like.

  The carbodiimide compound can be synthesized by a conventionally known technique, and generally a condensation reaction of a diisocyanate compound is used. The diisocyanate compound is not particularly limited, and any of aromatic and aliphatic compounds can be used. Specifically, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexa Examples include methylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate.

  Furthermore, in order not to lose the effect of the present invention, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound, adding a surfactant, polyalkylene oxide, quaternary ammonium salt of dialkylamino alcohol, You may add and use hydrophilic monomers, such as a hydroxyalkyl sulfonate.

  These cross-linking agents are used in a design that improves the performance of the coating layer by reacting in the drying process or film forming process. It can be inferred that unreacted products of these crosslinking agents, compounds after the reaction, or mixtures thereof exist in the finished coating layer.

  In forming the coating layer, particles may be used in combination for blocking, improving slipperiness, adjusting the bonding characteristics and the peeling characteristics.

By the above-mentioned coating layer, the bonding property to the polarizing film is greatly improved, but when the polyester film is formed into a roll, blocking may occur. As a measure for improvement, as a result of various studies, it has also been found that blocking can be reduced by providing a coating layer containing a release agent on the surface opposite to the coating layer having the bonding properties of the polyester film.

  In the present invention, it is also possible to provide a coating layer on the opposite side of the polyester film from the coating layer to be bonded to the polarizing film, mainly for the purpose of reducing blocking (hereinafter, described above). The coating layer to be bonded to the polarizing film may be referred to as a first coating layer, and the coating layer for reducing blocking provided on the opposite side of the polyester film from the first coating layer may be referred to as a second coating layer) .

  The second coating layer may be provided by in-line coating or offline coating may be employed. In-line coating is preferably used from the viewpoint of stabilization of the mold release performance by the manufacturing cost and in-line heat treatment.

  The second coating layer preferably contains a release agent in order to reduce blocking with the first coating layer. There is no restriction | limiting in particular as a mold release agent, It is possible to use a conventionally well-known mold release agent, For example, a long chain alkyl group containing compound, a fluorine compound, a silicone compound, wax etc. are mentioned. Among these, a long-chain alkyl compound and a fluorine compound are preferable from the viewpoint of low contamination and excellent blocking reduction, and a silicone compound is preferable when it is particularly important to reduce blocking. These release agents may be used alone or in combination.

  The long-chain alkyl group-containing compound is a compound having a linear or branched alkyl group having usually 6 or more, preferably 8 or more, and more preferably 12 or more carbon atoms. Examples of the alkyl group include hexyl group, octyl group, decyl group, lauryl group, octadecyl group, and behenyl group. Examples of the compound having an alkyl group include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, and long-chain alkyl group-containing quaternary ammonium salts. . In view of heat resistance and contamination, a polymer compound is preferable. Further, from the viewpoint of effectively obtaining releasability, a polymer compound having a long-chain alkyl group in the side chain is more preferable.

The polymer compound having a long-chain alkyl group in the side chain can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group. Examples of the reactive group include a hydroxyl group, an amino group, a carboxyl group, and an acid anhydride.
Examples of the compound having such a reactive group include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, a reactive group-containing polyester resin, and a reactive group-containing poly (meth) acrylic resin. Among these, polyvinyl alcohol is preferable in view of releasability and ease of handling.

  Examples of the compound having an alkyl group capable of reacting with the reactive group include, for example, long-chain alkyl group-containing isocyanates such as hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, and behenyl isocyanate, hexyl chloride, and octyl chloride. Long chain alkyl group-containing acid chlorides such as decyl chloride, lauryl chloride, octadecyl chloride, and behenyl chloride, long chain alkyl group-containing amines, and long chain alkyl group-containing alcohols. Among these, long chain alkyl group-containing isocyanates are preferable, and octadecyl isocyanate is particularly preferable in consideration of releasability and ease of handling.

  In addition, a polymer compound having a long-chain alkyl group in the side chain can also be obtained by copolymerization of a long-chain alkyl (meth) acrylate polymer or a long-chain alkyl (meth) acrylate and another vinyl group-containing monomer. . Examples of the long-chain alkyl (meth) acrylate include hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate, and behenyl (meth) acrylate. It is done.

  The fluorine compound is a compound containing a fluorine atom in the compound. Organic fluorine compounds are preferably used in terms of the appearance of coating by in-line coating, and examples thereof include perfluoroalkyl group-containing compounds, polymers of olefin compounds containing fluorine atoms, and aromatic fluorine compounds such as fluorobenzene. . From the viewpoint of releasability, a compound having a perfluoroalkyl group is preferable. Furthermore, the compound containing the long-chain alkyl compound which is mentioned later can also be used for a fluorine compound.

  Examples of the compound having a perfluoroalkyl group include perfluoroalkyl (meth) acrylate, perfluoroalkylmethyl (meth) acrylate, 2-perfluoroalkylethyl (meth) acrylate, and 3-perfluoroalkylpropyl (meth) acrylate. Perfluoroalkyl group-containing (meth) acrylates such as 3-perfluoroalkyl-1-methylpropyl (meth) acrylate and 3-perfluoroalkyl-2-propenyl (meth) acrylate, and polymers thereof, and perfluoroalkylmethyl vinyl ether 2-perfluoroalkyl ethyl vinyl ether, 3-perfluoropropyl vinyl ether, 3-perfluoroalkyl-1-methylpropyl vinyl ether, 3-perfluoroalkyl-2-propenyl vinyl Perfluoroalkyl group-containing vinyl ether and polymers thereof such as ether, and the like. In view of heat resistance and contamination, a polymer is preferable. The polymer may be a single compound or a polymer of multiple compounds. From the viewpoint of releasability, the perfluoroalkyl group preferably has 3 to 11 carbon atoms. Further, it may be a polymer with a compound containing a long-chain alkyl compound as described later. Moreover, it is also preferable that it is a polymer with vinyl chloride from a viewpoint of adhesiveness with a base material.

  The silicone compound is a compound having a silicone structure in the molecule, and examples thereof include alkyl silicones such as dimethyl silicone and diethyl silicone, phenyl silicones having a phenyl group, and methyl phenyl silicone. Silicones having various functional groups can also be used, such as ether groups, hydroxyl groups, amino groups, epoxy groups, carboxylic acid groups, halogen groups such as fluorine, perfluoroalkyl groups, various alkyl groups, and various types. Examples thereof include hydrocarbon groups such as aromatic groups. As other functional groups, silicones having vinyl groups and hydrogen silicones in which hydrogen atoms are directly bonded to silicon atoms are also common, and both are used in combination to form silicones (addition reaction between vinyl groups and hydrogen silane). It can also be used.

  Moreover, it is also possible to use modified silicones such as acrylic graft silicone, silicone graft acrylic, amino-modified silicone, and perfluoroalkyl-modified silicone as the silicone compound. In view of heat resistance and contamination, it is preferable to use a curable silicone resin. As the type of curable type, any of the curing reaction types such as a condensation type, an addition type, and an active energy ray curable type can be used. Among these, a condensation type silicone compound is preferred from the viewpoint that there is little back surface transfer when it is formed into a roll.

  In the case of using a silicone compound, a polyether group-containing silicone compound is preferable from the viewpoint of less back transfer, good dispersibility in an aqueous solvent and high suitability for in-line coating. The polyether group may be present in the side chain or terminal of the silicone or may be present in the main chain. From the viewpoint of dispersibility in an aqueous solvent, it is preferably present in the side chain or terminal.

  A conventionally well-known structure can be used for a polyether group. From the viewpoint of the dispersibility of the aqueous solvent, an aliphatic polyether group is preferable to an aromatic polyether group, and an alkyl polyether group is preferable among the aliphatic polyether groups. Further, from the viewpoint of synthesis due to steric hindrance, a linear alkyl polyether group is preferable to a branched alkyl polyether group, and among them, a polyether group composed of linear alkyl having 8 or less carbon atoms is preferable. Further, when the developing solvent is water, a polyethylene glycol group or a polypropylene glycol group is preferable in consideration of dispersibility in water, and a polyethylene glycol group is particularly optimal.

  The number of ether bonds of the polyether group is usually in the range of 1-30, preferably in the range of 2-20, more preferably 3 in terms of improving the dispersibility in an aqueous solvent and the durability of the coating layer. There are 15 ranges. When there are few ether bonds, dispersibility will worsen, and conversely too much, durability and mold release performance will worsen.

  When the polyether group has a side chain or a terminal of the silicone, the terminal of the polyether group is not particularly limited, and is a hydroxyl group, an amino group, a thiol group, a hydrocarbon group such as an alkyl group or a phenyl group, a carboxylic acid group, Various functional groups such as a sulfonic acid group, an aldehyde group, and an acetal group can be used. Among these, considering the dispersibility in water and the crosslinkability for improving the strength of the coating layer, a hydroxyl group, an amino group, a carboxylic acid group, and a sulfonic acid group are preferable, and a hydroxyl group is particularly optimal.

  The polyether group content of the polyether group-containing silicone is preferably in the range of 0.001 to 0.30, more preferably 0.01 to 0.20 in terms of a molar ratio, where the siloxane bond of the silicone is 1. %, More preferably 0.03 to 0.15%, particularly preferably 0.05 to 0.12%. By using it within this range, it is possible to maintain water dispersibility, durability of the coating layer and good releasability.

  The molecular weight of the polyether group-containing silicone is preferably not so large in consideration of dispersibility in an aqueous solvent, and is preferably in consideration of the durability and release performance of the coating layer. It is required to balance these characteristics, and the number average molecular weight is preferably in the range of 1000 to 100,000, more preferably in the range of 3000 to 30000, and still more preferably in the range of 5000 to 10,000.

  Further, considering the time-dependent change and release performance of the coating layer and the contamination of various processes, it is preferable that the silicone low molecular component (number average molecular weight is 500 or less) is as small as possible. The total ratio is preferably 15% by weight or less, more preferably 10% by weight or less, and further preferably 5% by weight or less. In addition, when using condensation type silicone, vinyl groups (vinyl silane) and hydrogen groups (hydrogen silane) bonded to silicon may cause changes in performance over time if left unreacted in the coating layer. The content of the functional group is preferably 0.1 mol% or less, more preferably not contained.

  Since polyether group-containing silicone is difficult to apply alone, it is preferable to use it dispersed in water. Various conventionally known dispersants can be used for dispersion, and examples thereof include anionic dispersants, nonionic dispersants, cationic dispersants, and amphoteric dispersants. Among these, when considering the dispersibility of the polyether group-containing silicone and the compatibility with a polymer other than the polyether group-containing silicone that can be used for forming the coating layer, an anionic dispersant and a nonionic dispersant are preferable. . Moreover, it is also possible to use a fluorine compound for these dispersing agents.

  Anionic dispersants include sodium dodecylbenzenesulfonate, sodium alkylsulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl allyl ether sulfate, polyoxyalkylene alkenyl. Sulfonates such as ether ammonium sulfate, sulfate esters, carboxylates such as sodium laurate and potassium oleate, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates Examples thereof include phosphates such as salts. Among these, a sulfonate system is preferable from the viewpoint of good dispersibility.

  Nonionic dispersants include, for example, ether type compounds in which alkylene oxides such as ethylene oxide and propylene oxide are added to compounds having hydroxyl groups such as higher alcohols and alkylphenols, and polyhydric alcohols such as glycerin and saccharides and ester bonds. Examples include an ester type, an ester / ether type in which an alkylene oxide is added to a fatty acid or a polyhydric alcohol fatty acid ester, and an amide type in which a hydrophobic group and a hydrophilic group are connected via an amide bond. Among these, an ether type is preferable in consideration of solubility in water and stability, and a type to which ethylene oxide is added is more preferable in consideration of handleability.

  Although it depends on the molecular weight and structure of the polyether group-containing silicone to be used and depends on the type of the dispersant to be used, it cannot be said unconditionally. As a weight ratio, it is preferably 0.01 to 0.5, more preferably 0.05 to 0.4, and still more preferably 0.1 to 0.3.

  The wax is a wax selected from natural waxes, synthetic waxes, and blended waxes thereof. Natural waxes are plant waxes, animal waxes, mineral waxes, and petroleum waxes. Examples of plant waxes include candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil and the like. Animal waxes include beeswax, lanolin, whale wax and the like. Examples of the mineral wax include montan wax, ozokerite, and ceresin. Examples of petroleum wax include paraffin wax, microcrystalline wax, and petrolatum. Synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, acid amides, amines, imides, esters, ketones, and the like. Synthetic hydrocarbons include, for example, Fischer-Tropsch wax (also known as Sazoir wax), polyethylene wax, and other low molecular weight polymers (specifically, polymers having a viscosity number average molecular weight of 500 to 20000). Examples of the following polymer include polypropylene, ethylene / acrylic acid copolymer, polyethylene glycol, polypropylene glycol, polyethylene glycol / polypropylene glycol block or graft conjugate, and the like. Examples of the modified wax include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. The derivative herein is a compound obtained by any of purification, oxidation, esterification, saponification treatment, or a combination thereof. Hydrogenated waxes include hardened castor oil and hardened castor oil derivatives.

  Among these, synthetic waxes are preferable from the viewpoint of stable characteristics, among which polyethylene wax is more preferable, and oxidized polyethylene wax is more preferable. The molecular weight of the synthetic wax is preferably in the range of 500 to 30000, more preferably 1000 to 15000, and still more preferably 2000 to 8000, from the viewpoints of stability of properties such as blocking and handleability.

  For the formation of the second coating layer, various polymers such as polyester resin, acrylic resin, urethane resin, and crosslinks that can be used for the formation of the first coating layer in order to improve the coating appearance and transparency and control the slipperiness. It is also possible to use a combination of agents. In particular, it is preferable to use a melamine compound, an oxazoline compound, an isocyanate compound, and an epoxy compound in terms of strengthening the coating layer and reducing blocking, and among them, a melamine compound is particularly preferable.

  As long as the gist of the present invention is not impaired, particles can be used in combination with the formation of the second coating layer in order to improve blocking and slipperiness.

  In some cases, such as when peeling electrification occurs, it may be preferable to use an antistatic agent in combination with the formation of the second coating layer in order to prevent dust adhesion.

  Furthermore, in the range that does not impair the gist of the present invention, the formation of the first coating layer and the second coating layer, if necessary, defoaming agent, coating property improver, thickener, organic lubricant, antistatic agent, It is also possible to use ultraviolet absorbers, antioxidants, foaming agents, dyes, pigments and the like in combination.

  As a preferred form constituting the laminated polyester film in the present invention, as a ratio in the first coating layer, the resin having a glass transition point of 0 ° C. or less is preferably 30% by weight or more, more preferably 50% by weight or more, More preferably, it is 65% by weight or more, particularly preferably 75% by weight or more, most preferably 85% by weight or more, and the upper limit of the preferred range is 99% by weight. By using in the above range, sufficient bonding characteristics can be easily obtained.

  As a preferred form constituting the laminated polyester film in the present invention, the proportion of the epoxy compound is preferably 50% by weight or less, more preferably 40% by weight or less, and still more preferably 30% by weight as the proportion in the first coating layer. The range is as follows. By using it in the above range, good coating strength and bonding characteristics can be easily obtained.

  As a preferred form constituting the laminated polyester film in the present invention, the proportion of the crosslinking agent other than the epoxy compound is preferably 30% by weight or less, more preferably 20% by weight or less, and still more preferably as the proportion in the first coating layer. Is in the range of 10 wt% or less. Good coating strength and adjusted bonding characteristics can be easily obtained by using in the above range, but depending on the material and composition used in the coating layer, the bonding characteristics may be reduced too much, so it should not be used May be preferred.

  As a preferable mode for constituting the laminated polyester film in the present invention, the ratio of the release agent as the ratio in the second coating layer cannot be generally specified because the appropriate amount varies depending on the type of the release agent, but preferably 3 It is in the range of not less than 15% by weight, more preferably not less than 15% by weight, still more preferably 25 to 99% by weight. If it is less than 3% by weight, the blocking reduction may not be sufficient.

  When a long-chain alkyl compound or a fluorine compound is used as the release agent, the proportion in the second coating layer is preferably 5% by weight or more, more preferably 15 to 99% by weight, and still more preferably 25 to 95% by weight. Particularly preferably, it is in the range of 40 to 90% by weight. By using it in the above range, blocking reduction is effective. The proportion of the crosslinking agent is preferably 95% by weight or less, more preferably 1 to 80% by weight, further preferably 5 to 70% by weight, and particularly preferably 10 to 50% by weight. Compounds and isocyanate compounds (block isocyanates blocked with active methylene compounds are particularly preferred among them) are preferred, and melamine compounds are particularly preferred from the viewpoint of reducing blocking.

  When a condensation-type silicone compound is used as a release agent, the proportion in the second coating layer is preferably 3% by weight or more, more preferably 5 to 97% by weight, still more preferably 8 to 95% by weight, and particularly Preferably it is the range of 10 to 90 weight%. By using it in the above range, blocking reduction is effective. The ratio of the crosslinking agent is preferably 97% by weight or less, more preferably 3 to 95% by weight, still more preferably 5 to 92% by weight, and particularly preferably 10 to 90% by weight. Moreover, as a crosslinking agent, a melamine compound is preferable from a viewpoint of blocking reduction.

  When an addition-type silicone compound is used as a release agent, the proportion in the second coating layer is preferably 5% by weight or more, more preferably 25% by weight or more, still more preferably 50% by weight or more, particularly preferably. It is in the range of 70% by weight or more. The upper limit of the preferable range is 99% by weight, and the more preferable upper limit is 90% by weight. By using in the said range, blocking reduction will become effective and the external appearance of a coating layer will also become favorable.

  When wax is used as the release agent, the ratio in the second coating layer is preferably 10% by weight or more, more preferably 20 to 90% by weight, and further preferably 25 to 70% by weight. By using it in the above range, blocking can be easily reduced. The proportion of the crosslinking agent is preferably 90% by weight or less, more preferably 10 to 70% by weight, and still more preferably 20 to 50% by weight. Moreover, as a crosslinking agent, a melamine compound is preferable from a viewpoint of blocking reduction.

  The analysis of the components in the coating layer can be performed, for example, by analysis of TOF-SIMS, ESCA, fluorescent X-ray, IR, or the like.

  Regarding the formation of the coating layer, the above-described series of compounds is used as a solution or solvent dispersion, and the coating solution adjusted with a solid content concentration of about 0.1 to 80% by weight as a guide is laminated on the polyester film. It is preferable to produce a polyester film. In particular, since the coating layer is provided by in-line coating, an aqueous solution or a water dispersion is more preferable. A small amount of an organic solvent may be contained in the coating solution for the purpose of improving the dispersibility in water, improving the film forming property, and the like. Moreover, only one type of organic solvent may be used, and two or more types may be used as appropriate.

  Regarding the laminated polyester film in the present invention, the thickness of the first coating layer provided on the polyester film is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm, and still more preferably 0.05 to 1.5 μm. Especially preferably, it is 0.06-0.90 micrometer, Most preferably, it is the range of 0.08-0.50 micrometer. By using the film thickness of the first coating layer in the above range, it becomes easy to maintain appropriate bonding characteristics, peeling characteristics and blocking characteristics. The film thickness of the second coating layer is preferably in the range of 0.001 to 1 μm, more preferably 0.01 to 0.5 μm, and still more preferably 0.02 to 0.2 μm. By using the film thickness of the second coating layer within the above range, it becomes easy to improve the blocking characteristics and to obtain a good coating appearance.

  In the film of the present invention, as a method for forming the coating layer, for example, gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze Conventionally known coating methods such as coating, impregnation coating, kiss coating, spray coating, calendar coating, extrusion coating, etc. can be used.

  In the present invention, the drying and curing conditions for forming the coating layer on the polyester film are not particularly limited, but the drying of a solvent such as water used in the coating solution is preferably 70 to It is 150 degreeC, More preferably, it is 80-130 degreeC, More preferably, it is the range of 90-120 degreeC. The drying time is generally 3 to 200 seconds, preferably 5 to 120 seconds. Moreover, in order to improve the intensity | strength of an application layer, in a film manufacturing process, Preferably it is 180-270 degreeC, More preferably, it is 200-250 degreeC, More preferably, it is passing through the heat treatment process of the range of 210-240 degreeC. The time for the heat treatment step is generally 3 to 200 seconds, preferably 5 to 120 seconds.

  Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed. The polyester film constituting the polyester film having the coating layer in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  The laminating force of the first coating layer of the present invention is preferably 3 to 2000 mN / cm, more preferably 5 to 1000 mN / cm, still more preferably 10 to 500 mN / cm, and particularly preferably 15 to the polarizing film. It is -200 mN / cm, Most preferably, it is the range of 15-100 mN / cm. By setting it in the above range, it has more appropriate bonding characteristics and peeling characteristics, and good film handling properties can be obtained.

  Moreover, roughening the film surface on the second coating layer side of the present invention may be one of the means for improving the blocking characteristics with the first coating layer side. Since it depends also on the presence and type of the second coating layer, it cannot be said unconditionally, but from the viewpoint of blocking characteristics, the arithmetic average roughness (Sa) of the surface on the second coating layer side is preferably 5 nm or more, More preferably, it is in the range of 10 nm or more, more preferably 20 nm or more, and the upper limit is not particularly limited, but the upper limit of the preferable range is 300 nm from the viewpoint of transparency. When the release force of the second coating layer is good, the influence of Sa is small because the influence of the second coating layer is dominant, but when the release force is weak, the influence of Sa may be large. is there.

  The film of the present invention is a film for a polarizing plate production process that is bonded to a polarizing film during the production process of the polarizing plate, and further peeled off during the process. The method of use is not particularly limited. For example, in order to temporarily protect the surface of the polarizing film, the polarized light on the side opposite to the side on which the adhesive layer or protective film of the polarizing film is formed. When it is directly bonded to the film surface and then peeled off when the surface of the polarizing film is processed (ie, the layer structure is (protective film) / adhesive layer / polarizing film / first coating layer / polyester) Film / second coating layer), directly attached to the surface of the polarizing film opposite to the side where the pressure-sensitive adhesive layer or release film is formed, and then processing the surface of the polarizing film. When peeled (that is, as the layer configuration, (release film) / adhesive layer / polarizing film / first coating layer / polyester film / second coating layer) and the like.

  The film of the present invention has an advantage that a film for protecting the pressure-sensitive adhesive layer is not required, unlike a film provided with a general pressure-sensitive adhesive layer, which eliminates the bonding process and effectively utilizes resources. There are significant cost advantages.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measurement method and evaluation method used in the present invention are as follows.

(1) Method for measuring the intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. And dissolved at 30 ° C.

(2) Measuring method of average particle diameter (d50: μm) Value of 50% of integration (weight basis) in equivalent spherical distribution measured using Shimadzu Corporation, centrifugal sedimentation type particle size distribution measuring device SA-CP3 type Was the average particle size.

(3) Measuring Method of Arithmetic Average Roughness (Sa) The non-contact surface / layer cross-sectional shape measurement system VertScan (registered by Ryoka System Co., Ltd.) is used for the film surface on the second coating layer side of Examples and Comparative Examples described later. (Trademark) Using R550GML, CCD camera: SONY HR-50 1/3 ', objective lens: 20x, lens barrel: 1X Body, zoom lens: No Relay, wavelength filter: 530 white, measurement mode: Wave Measured and output using fourth-order polynomial correction was used.

(4) Method for measuring film thickness of coating layer The surface of the coating layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by ultramicrotomy stained with RuO _4, a coating layer cross-section was measured by using a TEM (Hitachi High Technologies Corporation H-7650, accelerating voltage 100 V). The film thickness was measured at a location not including the particle portion.

(5) Glass transition point Using a differential scanning calorimeter (DSC) 8500, manufactured by PerkinElmer Japan Co., Ltd., measurement was performed at −100 to 200 ° C. under a temperature rising condition of 10 ° C. per minute.

(6) Number average molecular weight measurement method It measured using GPC (HLC-8120GPC by Tosoh Corporation). The number average molecular weight was calculated in terms of polystyrene.

(7) Functional group confirmation of silicone Polyether group-containing silicone was assigned to each peak of ¹ H-NMR using NMR (AVANCE III600 manufactured by Bruker Biospin), and the amount of dimethylsiloxane and polyether group, vinyl silane and hydrogen The presence or absence of silane was confirmed.

(8) Bonding force evaluation method for first coating layer The first coating layer surface of a laminated polyester film having a width of 5 cm is pressed once on a surface of a polarizing film made of a polyvinyl alcohol resin with a 2 kg rubber roller having a width of 5 cm, The peel force after standing for 1 hour at room temperature was measured. For the peeling force, “Ezgraph” manufactured by Shimadzu Corporation was used, and 180 ° peeling was performed under the condition of a tensile speed of 300 mm / min.

(9) Bonding characteristic evaluation method of first coating layer The first coating layer side of one A4 size polyester film and a polarizing film made of a 5 cm square polyvinyl alcohol resin are stacked and pressed with a finger to bond characteristics. Evaluated.
5 points when the film can be stuck just by holding it lightly with your finger, and it can be held even if you hold only the polyester film. 4 points when you can hold the attached state, the film sticks by pressing firmly with your finger, you can keep the attached state even if you have only the polyester film, but 3 points when you peel off within 3 seconds, When the film is pressed firmly with a finger, the bonding characteristics are very small on the film. However, 2 points are shown when the film cannot be stuck, and 1 point is when no bonding characteristics are seen even when pressed with a finger. did. In practical use, two or more points are preferable.

(10) Peeling property evaluation method of first coating layer Immediately after pressing the first coating layer surface of a 5 cm wide laminated polyester film on the surface of a polarizing film made of polyvinyl alcohol resin with a 5 cm wide 2 kg rubber roller, The film was peeled by hand to evaluate the peeling characteristics. The case where it peeled off easily was marked as ◯, the case where the sticking did not peel strongly, or the case where it was difficult to peel off was marked as x.

(11) Reworkability evaluation method for first coating layer In the evaluation method (9), after the film is peeled off, when the same operation is performed again at the same location, the evaluation result is equivalent to ○, bonding The case where the characteristics deteriorated was evaluated as x.

(12) Method for evaluating transfer property of first coating layer to polarizing film In the above evaluation method (9), after the attached film is peeled off, it is transferred to the polarizing film (transfer track of the coating layer). ), And ○ when there is transfer to a polarizing film.

(13) Measuring method of blocking property Two polyester films to be measured are prepared, the first coating layer side and the second coating layer side are overlapped, and an area of 12 cm × 10 cm is obtained at 40 ° C., 80% RH, 10 kg. / Cm ² , and pressed for 20 hours. Thereafter, the films were peeled according to the method specified in ASTM D1893, and the peel load was measured.
A lighter peeling load is more difficult to block, and is preferably 100 g / cm or less, more preferably 30 g / cm or less, still more preferably 20 g / cm or less, and particularly preferably 10 g / cm or less. In this evaluation, those exceeding 300 g / cm, those in which the film was torn during the evaluation, and those in which obvious blocking was generated by the press were not practical. In those cases, the evaluation was x. .

The polyester used in the examples and comparative examples was prepared as follows.
<Method for producing polyester (A)>
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, 30 ppm of ethyl acid phosphate with respect to the resulting polyester, and 100 ppm of magnesium acetate tetrahydrate with respect to the resulting polyester as the catalyst at 260 ° C. in a nitrogen atmosphere at 260 ° C. The reaction was allowed to proceed. Subsequently, 50 ppm of tetrabutyl titanate was added to the resulting polyester, the temperature was raised to 280 ° C. over 2 hours and 30 minutes, the pressure was reduced to 0.3 kPa in absolute pressure, and melt polycondensation was further carried out for 80 minutes. A polyester (A) having 0.63 and an amount of diethylene glycol of 2 mol% was obtained.

<Method for producing polyester (B)>
100 parts by weight of dimethyl terephthalate, 60 parts by weight of ethylene glycol, and magnesium acetate tetrahydrate as a catalyst were subjected to an esterification reaction at 225 ° C. in a nitrogen atmosphere at 900 ppm with respect to the produced polyester. Subsequently, 3500 ppm of orthophosphoric acid was added to the produced polyester, and 70 ppm of germanium dioxide was added to the produced polyester. The temperature was raised to 280 ° C. over 2 hours and 30 minutes, and the pressure was reduced to an absolute pressure of 0.4 kPa. After 85 minutes of melt polycondensation, polyester (B) having an intrinsic viscosity of 0.64 and a diethylene glycol amount of 2 mol% was obtained.

<Method for producing polyester (C)>
In the production method of the polyester (A), the polyester (C) is produced using the same method as the production method of the polyester (A) except that 0.6 parts by weight of silica particles having an average particle diameter of 3.2 μm is added before the melt polymerization. Got.

<Method for producing polyester (D)>
In the production method of the polyester (A), the polyester (D) is produced using the same method as the production method of the polyester (A) except that 0.3 part by weight of silica particles having an average particle diameter of 2.7 μm is added before the melt polymerization. Got.

Examples of compounds constituting the coating layer are as follows.
(Example compounds)
・ Polyester resin: (IA)
Water dispersion of polyester resin (glass transition point: −20 ° C.) having the following composition: Monomer composition: (acid component) dodecanedicarboxylic acid / terephthalic acid / isophthalic acid / 5-sodiumsulfoisophthalic acid // (diol component) ethylene Glycol / 1,4-butanediol = 20/38/38/4 // 40/60 (mol%)
・ Polyester resin: (IB)
Water dispersion of polyester resin (glass transition point: −30 ° C.) having the following composition: Monomer composition: (acid component) dodecanedicarboxylic acid / terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene Glycol / 1,4-butanediol = 30/33/33/4 // 40/60 (mol%)
・ Polyester resin: (IC)
Water dispersion of polyester resin (glass transition point: 30 ° C.) having the following composition: Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4 -Butanediol / diethylene glycol = 40/56/4 // 45/25/30 (mol%)
・ Polyester resin: (ID)
Water dispersion of polyester resin having the following composition: Monomer composition: (acid component) terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid // (diol component) ethylene glycol / 1,4-butanediol / diethylene glycol = 56 / 40/4 // 70/20/10 (mol%)

・ Acrylic resin: (IIA)
Aqueous dispersion of acrylic resin (glass transition point: −25 ° C.) having the following composition: normal butyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate / acrylic acid = 72/23/3/2 (% by weight)
・ Acrylic resin: (IIB)
Aqueous dispersion of acrylic resin (glass transition point: −40 ° C.) having the following composition: normal butyl acrylate / 2-ethylhexyl acrylate / ethyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 30/30/36/2 / 2 (% by weight)

・ Acrylic resin: (IIC)
Aqueous dispersion of acrylic resin (glass transition point: −50 ° C.) having the following composition: 2-ethylhexyl acrylate / lauryl methacrylate / 2-hydroxyethyl methacrylate / acrylic acid / methacrylic acid = 50/25/15/5/5 (weight%)
・ Acrylic resin: (IID)
Aqueous dispersion of acrylic resin (glass transition point: −55 ° C.) having the following composition 2-ethylhexyl acrylate / vinyl acetate / acrylic acid = 78/20/2 (% by weight)

・ Acrylic resin: (IIE)
Aqueous dispersion of acrylic resin (glass transition point: −15 ° C.) having the following composition: normal butyl acrylate / ethyl acrylate / methyl methacrylate / acrylic acid = 45/23/30/2 (% by weight)
・ Acrylic resin: (IIF)
Aqueous dispersion of acrylic resin (glass transition point: 10 ° C.) having the following composition: ethyl acrylate / normal butyl methacrylate / acrylic acid = 25/73/2 (% by weight)

-Urethane resin: (III)
Consists of 80 parts of polycarbonate polyol having a number average molecular weight of 2000 consisting of 1,6-hexanediol and diethyl carbonate, 4 parts of polyethylene glycol having a number average molecular weight of 400, 12 parts of methylenebis (4-cyclohexylisocyanate), and 4 parts of dimethylolbutanoic acid. Water dispersion obtained by neutralizing urethane resin with triethylamine (glass transition point: -30 ° C)

・ Epoxy compound: (IVA) Polyglycerol polyglycidyl ether which is a polyfunctional polyepoxy compound ・ Melamine compound: (IVB) Hexamethoxymethylolmelamine ・ Oxazoline compound: (IVC)
Acrylic polymer having an oxazoline group and a polyalkylene oxide chain Epocross (Oxazoline group amount = 4.5 mmol / g, manufactured by Nippon Shokubai Co., Ltd.)

・ Isocyanate compounds: (IVD)
1000 parts of hexamethylene diisocyanate was stirred at 60 ° C., and 0.1 part of tetramethylammonium capryate was added as a catalyst. After 4 hours, 0.2 part of phosphoric acid was added to stop the reaction, and an isocyanurate type polyisocyanate composition was obtained. 100 parts of the obtained isocyanurate type polyisocyanate composition, 42.3 parts of methoxypolyethylene glycol having a number average molecular weight of 400, and 29.5 parts of propylene glycol monomethyl ether acetate were charged and maintained at 80 ° C. for 7 hours. Thereafter, the reaction solution temperature was kept at 60 ° C., 35.8 parts of methyl isobutanoyl acetate, 32.2 parts of diethyl malonate, and 0.88 part of 28% methanol solution of sodium methoxide were added and kept for 4 hours. Block polyisocyanate with active methylene obtained by adding 58.9 parts of n-butanol, maintaining the reaction solution temperature at 80 ° C. for 2 hours, and then adding 0.86 part of 2-ethylhexyl acid phosphate.

-Particles: (V) Silica particles with an average particle size of 0.05 μm

・ Releasing agent (long chain alkyl group-containing compound): (VIA)
To a four-necked flask, 200 parts of xylene and 600 parts of octadecyl isocyanate were added and heated with stirring. From the time when xylene began to reflux, 100 parts of polyvinyl alcohol having an average degree of polymerization of 500 and a degree of saponification of 88 mol% was added in small portions over a period of about 2 hours. After the addition of polyvinyl alcohol, the reaction was completed by further refluxing for 2 hours. When the reaction mixture was cooled to about 80 ° C. and added to methanol, the reaction product was precipitated as a white precipitate. This precipitate was filtered off, added with 140 parts of xylene, and heated to dissolve completely. After repeating the operation of adding methanol again to precipitate several times, the precipitate was washed with methanol and dried and ground.

・ Releasing agent (fluorine compound): (VIB)
Fluorine compound aqueous dispersion having the following composition: Octadecyl acrylate / perfluorohexyl ethyl methacrylate / vinyl chloride = 66/17/17 (% by weight)

-Polyether group-containing condensed silicone: (VIC)
Polyether group-containing silicone having a number average molecular weight of 7000 (silicone siloxane) containing 1 polyethylene glycol (terminated with a hydroxyl group) having an ethylene glycol chain of 8 with respect to dimethylsiloxane 100 in the dimethyl silicone side chain in a molar ratio. When the bond is 1, the ether bond of the polyether group is 0.07 at a molar ratio). 3% of low molecular components having a number average molecular weight of 500 or less, no vinyl group (vinyl silane) and hydrogen group (hydrogen silane) bonded to silicon exist. In addition, this compound mix | blends the water which disperse | distributes sodium dodecyl benzenesulfonate in the ratio of 0.25 by making polyether group containing silicone 1 by weight ratio.

・ Additional silicone: (VID)
Addition-type silicone aqueous dispersion mixed with a compound of the following composition: methyl hydrogen polysiloxane containing 80% by weight of methyl vinyl polysiloxane containing 0.6 mol% of vinyl groups and 30 mol% of hydrogen silane groups (hydrogen groups) 5% by weight, 5% by weight of 3-glycidoxypropyltrimethoxysilane, 10% by weight of polyethylene glycol butyl ether, and an aqueous dispersion containing a platinum catalyst.

・ Wax: (VIE)
An emulsification facility with an internal volume of 1.5 L equipped with a stirrer, thermometer, temperature controller, melting point 105 ° C., acid value 16 mgKOH / g, density 0.93 g / mL, average molecular weight 5000 oxidized polyethylene wax 300 g, ion-exchanged water 650 g 50 g of decaglycerin monooleate surfactant and 10 g of 48% potassium hydroxide aqueous solution were added and replaced with nitrogen, then sealed, stirred at 150 ° C for 1 hour at high speed, cooled to 130 ° C, and passed through a high-pressure homogenizer at 400 atm. A wax emulsion cooled to 40 ° C.

Antistatic agent (quaternary ammonium salt compound): (VII)
Polymer polymerized with the following composition having a pyrrolidinium ring in the main chain: Diallyldimethylammonium chloride / dimethylacrylamide / N-methylolacrylamide = 90/5/5 (mol%). Number average molecular weight 30000.

Example 1:
A mixed raw material in which polyesters (A), (B), and (C) were mixed in proportions of 72%, 3%, and 25%, respectively, was used as a raw material for the outermost layer (surface layer), and polyesters (A) and (B) were each 97 %, 3% of the mixed raw material is used as an intermediate layer raw material, each is supplied to two extruders, melted at 285 ° C., and then on a cooling roll set at 40 ° C. Coextruded and cooled and solidified with a layer structure of layers (surface layer / intermediate layer / surface layer = 3: 19: 3 discharge amount) to obtain an unstretched sheet. Next, the film was stretched 3.2 times in the machine direction at a film temperature of 85 ° C. using the roll peripheral speed difference, and then the coating liquid A1 shown in Table 1 below was applied on one side of the longitudinally stretched film to the film thickness (dried) (After) is applied to 0.20 μm (first coating layer), and coating liquid B1 shown in the following Table 2 is applied to the opposite surface so that the coating layer thickness (after drying) is 0.03 μm. After coating (second coating layer), guiding to a tenter, drying at 95 ° C. for 10 seconds, stretching 4.3 times at 120 ° C. in the transverse direction, heat-treating at 230 ° C. for 10 seconds, and then transversely The polyester film was relaxed by 2%, the thickness was 25 μm, and the surface of Sa on the second coating layer side was 30 nm.

  When the finished polyester film was evaluated, the laminating properties, peeling properties, transfer properties and blocking properties were good. The properties of this film are shown in Table 3 below.

Examples 2-45:
In Example 1, except having changed a coating agent composition into the coating agent composition shown to Table 1 and 2, it manufactured like Example 1 and the polyester film was obtained. As shown in Table 3 or 4 below, the finished polyester film had good bonding characteristics, peeling characteristics, transfer characteristics, and blocking characteristics.

Examples 46-55:
In Example 1, the polyester composition of the surface layer is a mixed raw material in which polyesters (A), (B), and (D) are mixed in proportions of 80%, 3%, and 17%, respectively, and the layer configuration is two types and three layers ( Production is carried out in the same manner as in Example 1 except that the coating composition is coextruded with a layer composition of (surface layer / intermediate layer / surface layer = 3: 19: 3) and the coating composition is changed to the coating composition shown in Tables 1 and 2. A polyester film was obtained. The Sa on the surface of the finished polyester film on the second coating layer side was 12 nm, and the bonding characteristics, peeling characteristics, transfer characteristics and blocking characteristics were good. The properties of this film are shown in Table 5 below.

Examples 56-65:
In Example 1, the polyester composition of the surface layer is a mixed raw material in which polyesters (A), (B), and (D) are mixed in proportions of 91%, 3%, and 6%, respectively, and the layer structure is two types and three layers ( Production is carried out in the same manner as in Example 1 except that the coating composition is coextruded with a layer composition of (surface layer / intermediate layer / surface layer = 3: 19: 3) and the coating composition is changed to the coating composition shown in Tables 1 and 2. A polyester film was obtained. Sa on the surface of the finished polyester film on the second coating layer side was 9 nm, and the bonding characteristics, peeling characteristics, transfer characteristics and blocking characteristics were good. The properties of this film are shown in Table 5 below.

Comparative Example 1:
In Example 1, it manufactured similarly to Example 1 except having not provided the application layer, and obtained the polyester film. When the completed polyester film was evaluated, as shown in Table 6 below, it was a film having no bonding characteristics.

Comparative Example 2:
On the polyester film without the coating layer obtained in Comparative Example 1, the coating solution C1 shown in Table 1 below was applied so that the coating layer thickness (after drying) was 0.20 μm, and the coating layer was 100 ° C. for 60 seconds. Was dried to obtain a polyester film on which the first coating layer by off-line coating was laminated. Thereafter, coating liquid B4 shown in Table 2 below is applied to the opposite side of the polyester film from the first coating layer so that the thickness of the coating layer (after drying) is 0.03 μm, and at 100 ° C. for 60 seconds. The polyester film on which the second coating layer by off-line coating was laminated was obtained. As shown in Table 6, the finished polyester film was a film having no bonding characteristics.

Comparative Examples 3-7:
In Comparative Example 2, a polyester film was produced in the same manner as in Comparative Example 2 except that the coating composition was changed to the coating composition shown in Tables 1 and 2 to obtain a polyester film on which a coating layer by offline coating was laminated. As shown in Table 6, the finished polyester film was a film having poor bonding characteristics or a film having poor transfer characteristics.

The polarizing plate of the present invention has few fish eyes, excellent mechanical strength and heat resistance during the manufacturing process of the polarizing plate, is easily bonded to the polarizing film, and is further easily peeled off during the process. a polarizer manufacturing process for film, which utilizes a film which is Ru can be protected that the defects of scratches in handling properties improved and the polarizing film of the polarizing film enters, suitably for various optical applications Can be used.

Claims (14)

A coating layer having a thickness of 0.01 to 10 μm is formed on at least one surface of the polyester film by in-line coating, and the coating layer is directly bonded to the polarizing film during the polarizing plate manufacturing process. Furthermore, the manufacturing method of the polyester film which peels and uses it in the said process . The manufacturing method of the polyester film of Claim 1 which has a coating layer containing a mold release agent in the surface on the opposite side to the polyester film surface side which bonds a polarizing film. The method for producing a polyester film according to claim 1, wherein the polarizing film is made of a polyvinyl alcohol resin. The manufacturing method of the polyester film in any one of Claims 1-3 which contains resin whose glass transition point is 0 degrees C or less in the application layer of the side bonded with a polarizing film. The manufacturing method of the polyester film in any one of Claims 1-4 whose bonding force with respect to the polarizing film of the application layer of the side bonded with a polarizing film is 3-2000 mN / cm. The manufacturing method of the polyester film in any one of Claims 1-5 which contains a polyester resin in the application layer of the side bonded with a polarizing film. The method for producing a polyester film according to claim 6, wherein the coating layer on the side to be bonded to the polarizing film is formed from a polyester resin, and the polyester resin contains an aliphatic polyvalent carboxylic acid or an aliphatic polyvalent hydroxy compound as a constituent component. The method for producing a polyester film according to claim 6 or 7, wherein the polyester resin is water-based. The manufacturing method of the polyester film in any one of Claims 1-5 in which the application layer of the side bonded with a polarizing film contains an acrylic resin. The method for producing a polyester film according to claim 9, wherein the content of the monomer having a glass transition point of the homopolymer constituting the acrylic resin of 0 ° C. or less is 30% by weight or more as a ratio to the whole acrylic resin. The method for producing a polyester film according to claim 9 or 10, wherein the alkyl group of the monomer constituting the acrylic resin has 4 to 30 carbon atoms. The method for producing a polyester film according to any one of claims 9 to 11, wherein the acrylic resin is an aqueous dispersion. The manufacturing method of the polyester film in any one of Claims 2-12 in which the coating layer containing a mold release agent contains a crosslinking agent. A film obtained by forming an application layer having a thickness of 0.01 to 10 μm on at least one surface of the polyester film by in-line coating is applied to the polarizing film directly in the polarizing plate manufacturing process. A method for producing a polarizing plate, further comprising peeling during the process.