JP2017154128A - Method for producing laminated polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a laminated polyester film which can be suitably used for various applications required to have good adhesive characteristics, for instance, applications of the surface protective film used for prevention against scratches and prevention against stain adhesion at the time of transportation, storage and processing of a resin plate and a metal plate.SOLUTION: A method for producing a laminated polyester film includes providing a coating layer containing a (meth)acrylic resin, which has 20 wt.% or more of a (meth)acrylate unit having an alkyl group having 4 or more carbon atoms in an ester terminal, on at least one surface of a polyester film, and stretching the coating layer in at least one direction to form an adhesive layer.SELECTED DRAWING: None

Description

  The present invention relates to a laminated polyester film. For example, there are few fish eyes as a surface protection film for preventing scratches and preventing adhesion of dirt during transport, storage and processing of resin plates, metal plates, etc. The present invention relates to a method for producing a laminated polyester film having excellent mechanical strength and heat resistance, good adhesive properties, and good substrate adhesion.

  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 adhesive force to the adherend during transport, storage, processing, etc. of various adherends such as resin plates, metal plates and glass plates, It is required that the surface of the adherend be protected by adhering to the surface of the adherend 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).

  However, since a polyolefin-based film is used as the surface protective film substrate, it is not possible to remove defects caused by gel-like materials and deteriorated products, which are generally called fisheye, For example, when inspecting an adherend in a state where the surface protective film is bonded, there is a problem that it becomes an obstacle such as detecting a defect of the surface protective film.

  In addition, as a base material for the surface protection film, a film having a certain degree of mechanical strength is required so that the base material is not stretched due to tension during various processing such as bonding to an adherend. However, since polyolefin films generally have poor mechanical strength, they have the disadvantage of being unsuitable for high-tension processing due to increasing the 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

  The present invention has been made in view of the above circumstances, and the problem to be solved is that there are few fish eyes used for various surface protection films, etc., excellent mechanical strength and heat resistance, and good adhesive properties. It is providing the manufacturing method of a laminated polyester film.

  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 is that a coating layer containing a (meth) acrylic resin having at least one (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at an ester terminal is provided on at least one surface of a polyester film. The present invention resides in a method for producing a laminated polyester film, characterized in that an adhesive layer is formed by stretching the coating layer in at least one direction.

  According to the laminated polyester film of the present invention, as various surface protective films, it is possible to provide a film having few fish eyes, excellent mechanical strength and heat resistance, and having good adhesive properties and good substrate adhesion. , 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 adhesive properties are greatly lowered, which cannot be achieved with a general polyester film. Therefore, improvement was achieved by providing an adhesive layer on the substrate film, and the present invention was achieved.

  The polyester film constituting the laminated polyester film may have a single layer configuration or a multilayer configuration, and may have a multilayer of 4 layers or more as long as it does not exceed the gist of the present invention other than the configuration of 2 layers or 3 layers. There may be, and it is not specifically 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 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 mechanical strength and heat resistance (dimensional stability by heating) are high, and for that purpose, it is sometimes preferable that the amount of the copolyester 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 consideration of ease of handling and handling properties as a surface 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. Since transparency of this becomes high, it is preferable. 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, particles can be blended for the purpose of imparting slipperiness, preventing generation of 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 0.01 to 5 μm, and still more preferably 0.01 to 3 μm. When the average particle size exceeds 10 μm, there may be a concern about a problem due to a decrease 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 such as dropout of particles and a decrease in transparency of the film. When there are no particles or when there are few particles, the slipperiness may be insufficient. Therefore, a device such as improving the slipperiness may be required by putting particles in the adhesive layer.

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

  The thickness of the polyester film 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 8 to 75 μm.

  Although the production example of the film will be specifically described, it is not limited to the following production example, and a generally known film forming method can be adopted. In general, the resin is melted, formed into a sheet, and stretched for the purpose of increasing the strength and the film is formed. For example, when producing a biaxially stretched polyester film, first, a polyester raw material is 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 preferably 70 to 120 ° C, more preferably 80 to 110 ° C, and the stretching ratio is preferably 2.5 to 7 times, more preferably 3.0 to 6 times. Next, the film is stretched in the direction orthogonal to the first-stage stretching direction, preferably at 70 to 170 ° C., and the stretching ratio is preferably 2.5 to 7 times, more 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% is 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.

  A simultaneous biaxial stretching method can also 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 adhesion layer which comprises a laminated polyester film is demonstrated. The adhesive layer is formed by stretching in at least one direction. By stretching the adhesive layer, the adhesiveness with the base film is strengthened, and there is an aim to reduce the migration (adhesive residue) of the adhesive component to the adherend. The forming method is coating (application). According to the coating, the pressure-sensitive adhesive layer can be easily formed and stretched easily.

  As a method by coating, it may be provided by in-line coating performed in the film production process, or may be provided by off-line coating in which the film once produced is coated outside the system. Since there is a possibility of inducing film defects such as wrinkles when the film is stretched after off-line coating, it is more preferably formed by in-line coating.

  Specifically, the in-line coating is a method in which coating is performed at an arbitrary stage from melt extrusion of a resin forming a film to heat setting after stretching and winding. Usually, it is coated on either an unstretched sheet obtained by melting and rapid cooling 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, since film formation and adhesion layer formation can be performed simultaneously, there is a merit in manufacturing cost, and in order to perform stretching after coating, the thickness of the adhesion layer can be changed by the stretching ratio. Compared to offline coating, thin film coating can be performed more easily.

  Moreover, by providing the adhesive layer on the film before stretching, the adhesive layer can be stretched together with the base film, whereby the adhesive 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 adhesive layer can be improved, and the adhesive layer and the base film can be more firmly adhered to each other. In addition, a strong adhesive layer can be obtained. In particular, it is very effective for reacting a crosslinking agent.

  According to the above-mentioned process by in-line coating, the film size does not change greatly depending on whether or not the adhesive layer is formed, and the risk of scratches and adhesion of foreign substances does not change greatly depending on whether or not the adhesive 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 the advantage of reducing adhesive residue, which is a transfer of components of the adhesive layer when the film of the present invention is bonded to an adherend. It was. This is because heat treatment can be performed at a high temperature that cannot be obtained by off-line coating, and the adhesive layer and the base film are considered to be a result of more tight adhesion.

  In the present invention, it is an essential requirement to have a pressure-sensitive adhesive layer containing a (meth) acrylic resin having a (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester terminal and having 20% by weight or more. is there.

  The (meth) acrylic resin having a (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester terminal is 20% by weight or more is a polymer composed of a polymerizable monomer containing an acrylic or methacrylic monomer. Yes (Hereinafter, acrylic and methacryl may be abbreviated as (meth) acryl), and a (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester terminal is used for the entire (meth) acrylic resin. Among them, the resin is 20% by weight or more. 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. However, in consideration of adhesive properties and adhesive residue on the adherend, it should not contain other polymers such as polyester and polyurethane (polymerizable monomers containing carbon-carbon double bonds (whether homopolymers or copolymers) (Meth) acrylic resin composed only of (possible)) is preferable.

  As the (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester end, a conventionally known (meth) acrylate can be used. Of these, (meth) acrylates having a glass transition point of homopolymer of 0 ° C. or lower are particularly preferable. For example, normal butyl acrylate (glass transition point: −55 ° C.), normal hexyl acrylate (glass transition point: −57 ° C.) 2-ethylhexyl acrylate (glass transition point: −70 ° C.), normal octyl acrylate (glass transition point: −65 ° C.), isooctyl acrylate (glass transition point: −83 ° C.), normal nonyl acrylate (glass transition point) : -63 ° C), normal nonyl methacrylate (glass transition point: -35 ° C), isononyl acrylate (glass transition point: -82 ° C), normal decyl acrylate (glass transition point: -70 ° C), normal decyl methacrylate (glass) Transition point: -45 ° C), isodecyl acrylate (Gala Transition point: -55 ° C), isodecyl methacrylate (glass transition point: -41 ° C), lauryl acrylate (glass transition point: -30 ° C), lauryl methacrylate (glass transition point: -65 ° C), tridecyl acrylate (glass) Transition point: -75 ° C), tridecyl methacrylate (glass transition point: -46 ° C), isomistyryl acrylate (glass transition point: -56 ° C), and the like.

  Among these, in order to improve adhesive properties, the alkyl (meth) acrylate is preferably an alkyl group having 4 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, and further preferably 4 to 14 carbon atoms. It is. Industrially mass-produced, and (meth) acrylic resins containing normal butyl acrylate and 2-ethylhexyl acrylate are optimal from the viewpoints of handleability and supply stability.

  The content in the (meth) acrylic resin of the (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester end is required to be 20% by weight or more, preferably 35 to 99% by weight, more preferably It is 50 to 98% by weight, more preferably 65 to 95% by weight, and particularly preferably 75 to 90% by weight. The greater the content of the (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester end, the stronger the adhesive property. Conversely, when the content is too small, the adhesive strength is not sufficient.

  As a component other than the (meth) acrylate unit having an alkyl group having 4 or more carbon atoms in the (meth) acrylic resin at the ester end, a conventionally known polymerizable monomer can be used, and is not particularly limited. Representative compounds include, for example, various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, and salts thereof; 2-hydroxyethyl (meta ) Various hydroxyl group-containing monomers such as acrylate and 2-hydroxypropyl (meth) acrylate; Various (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate ; (Meth) acrylamide, diacetone acrylamide, N-me Various nitrogen-containing compounds such as roll acrylamide 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, etc .; phosphorus-containing vinyl monomers; various vinyl halides such as vinyl chloride and biridene chloride; butadiene And various conjugated dienes.

  Among these, from the viewpoint of adhesive properties, (meth) acrylates having a homopolymer glass transition point of 0 ° C. or less are preferred, and ethyl acrylate (glass transition point: −22 ° C.), normal propyl acrylate (glass transition point: (-37 ° C.), isopropyl acrylate (glass transition point: −5 ° C.) and the like, and (meth) acrylates having an alkyl group having less than 4 carbon atoms at the ester terminal are exemplified. Among these, ethyl acrylate is particularly preferable from the viewpoint of handling. preferable.

  In the above (meth) acrylic resin, the content of the (meth) acrylate unit having a glass transition point of the homopolymer of 0 ° C. or less and having an alkyl group having less than 4 carbon atoms at the ester terminal is preferably 50% by weight. Hereinafter, it is more preferably in the range of 40% by weight or less, and further preferably in the range of 30% by weight or less. By using in the above range, good adhesive properties are obtained.

  In addition, from the viewpoint that the migration of the adhesive component to the adherend can be reduced, among the above, a compound having 2 or less carbon atoms contained in the ester terminal or a compound having a cyclic structure is preferable, and more preferable. Is a compound having 1 carbon atoms or an aromatic compound. Specific examples include methyl methacrylate, acrylonitrile, styrene, and cyclohexyl acrylate as preferable compounds.

  The content of the compound unit having 2 or less carbon atoms contained in the ester terminal in the (meth) acrylic resin is preferably 50% by weight or less, more preferably 1 to 40% by weight, and still more preferably 3 to 3%. It is in the range of 30% by weight, particularly preferably 5 to 20% by weight. If the content of the unit is small, it is possible to impart an appropriate range of adhesive properties without greatly degrading the adhesive properties. Conversely, if the content is high, the content of the unit is greater on the adherend. It is possible to reduce the migration of the adhesive component. Therefore, if it is the said range, it will become easy to achieve the two objectives, adhesive characteristics and migration reduction.

  In the (meth) acrylic resin, the content of the compound unit having a cyclic structure is preferably 50% by weight or less, more preferably 1 to 45% by weight, and still more preferably 5 to 40% by weight. If the content of the unit is small, it is possible to impart an appropriate range of adhesive properties without greatly degrading the adhesive properties. Conversely, if the content is high, the content of the unit is greater on the adherend. It is possible to reduce the migration of the adhesive component. Therefore, if it is the said range, it will become easy to achieve the two objectives, adhesive characteristics and migration reduction.

  From the viewpoint of adhesive properties, the content of the monomer having a glass transition point of the homopolymer of 0 ° C. or less as the monomer constituting the (meth) acrylic resin is preferably 30% by weight as a proportion of the whole (meth) acrylic resin. Above, more preferably 45% by weight or more, still more preferably 60% by weight or more, particularly preferably 70% by weight or more. The upper limit of the preferred range is 99% by weight. It is easy to obtain good adhesive properties by using in this range.

  Moreover, as a glass transition point of the monomer whose homopolymer has a glass transition point of 0 ° C. or lower for improving the adhesive property, it is preferably −20 ° C. or lower, more preferably −30 ° C. or lower, and further preferably −40 ° C. or lower. Especially preferably, it is -50 degrees C or less, and the minimum of a preferable range is -100 degreeC. By using it in the said range, it becomes easy to set it as the film which has moderate adhesive characteristics.

  As a more optimal form of (meth) acrylic resin for improving the adhesive properties, the total content of normal butyl acrylate and 2-ethylhexyl acrylate in (meth) acrylic resin is preferably 30% by weight or more. More preferably, it is 40% by weight or more, more preferably 50% by weight or more, particularly preferably 60% by weight or more, and most preferably 70% by weight or more. The upper limit of the preferred range is 99% by weight. Although it depends on the composition of the (meth) acrylic resin to be used and the composition of the adhesive layer, 2-ethylhexyl is particularly useful when it is desired to eliminate the transfer of the adhesive component to the adherend with a small amount of the crosslinking agent. The acrylate content is preferably 90% by weight or less, more preferably 80% by weight or less.

  The glass transition point of the (meth) acrylic resin for improving the adhesive properties is essential to be 0 ° C. or lower, preferably −10 ° C. or lower, more preferably −20 ° C. or lower, and still more preferably. The lower limit of the preferable range is −80 ° C. It becomes easy to set it as the film which has the optimal adhesion characteristic by using in the said range. Moreover, when it is necessary to consider the reduction | decrease of transfer of the adhesion component to a to-be-adhered body, Preferably it is -70 degreeC or more, More preferably, it is -60 degreeC or more, More preferably, it is the range of -50 degreeC or more.

  In consideration of application to in-line coating, etc., various hydrophilic functional groups can be introduced in order to obtain an aqueous (meth) acrylic resin. Preferred examples of the hydrophilic functional group include a carboxylic acid group, a carboxylic acid group, a sulfonic acid group, a sulfonic acid group, and a hydroxyl group. Among these, a carboxylic acid group, a carboxylic acid group, and a hydroxyl group are preferable from the viewpoint of water resistance.

  Examples of the introduction of carboxylic acid include copolymerization of various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Among these, acrylic acid and methacrylic acid are preferred because effective water dispersion is possible.

  As the introduction of a hydroxyl group, various types such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxyl fumarate, monobutyl hydroxy itaconate Examples thereof include copolymerizing a hydroxyl group-containing monomer.

  In addition, a copolymer of an amino group-containing monomer such as dimethylaminoethyl (meth) acrylate or a copolymer of an epoxy group-containing monomer such as glycidyl (meth) acrylate can be contained as a crosslinking reactive group. . However, if the content is too large, the adhesive properties are affected, so an appropriate amount is required.

  The proportion of the hydrophilic functional group-containing monomer in the (meth) acrylic resin is preferably 30% by weight or less, more preferably 1 to 20% by weight, still more preferably 2 to 15% by weight, particularly preferably 3 to 10% by weight. Range. By using it in the above range, it becomes easy to develop an aqueous system.

  Moreover, it is also preferable to use a crosslinking agent together from the viewpoint of the strength of the adhesive layer. The main focus was the study of adhesive layers using (meth) acrylic resins having a (meth) acrylate unit having an alkyl group with 4 or more carbon atoms at the end of the ester, but it was used under severe conditions. It has been found in the study that depending on the (meth) acrylic resin, the adhesive component migrates to the adherend. As a result of various studies, it was also found that the use of a crosslinking agent together can improve the transfer of the adhesive layer to the adherend.

  As the crosslinking agent, conventionally known materials can be used, and examples thereof include melamine compounds, isocyanate compounds, epoxy compounds, oxazoline compounds, carbodiimide compounds, silane coupling compounds, hydrazide compounds, and aziridine compounds. Among them, melamine compounds, isocyanate compounds, epoxy compounds, oxazoline compounds, carbodiimide compounds, and silane coupling compounds are preferable, and melamine compounds and isocyanate compounds are preferable from the viewpoint that adhesive strength can be appropriately maintained and adjusted easily. A compound and an epoxy compound are more preferable, and an isocyanate compound and an epoxy compound are particularly preferable because a decrease in adhesive strength due to the combined use can be suppressed. In particular, from the viewpoint that migration to an adherend can be reduced, melamine compounds and isocyanate compounds are preferable, and among them, melamine compounds are particularly preferable. Furthermore, a melamine compound is particularly preferable from the viewpoint of the strength of the adhesive layer. These crosslinking agents may be used alone or in combination of two or more.

  Depending on the configuration of the pressure-sensitive adhesive layer and the type of crosslinking agent, if the content of the crosslinking agent in the pressure-sensitive adhesive layer is excessive, the pressure-sensitive adhesive characteristics may be deteriorated too much. Therefore, it is necessary to pay attention to the content in the adhesive layer.

  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 isocyanate compound is a compound having an isocyanate derivative structure typified by isocyanate or blocked isocyanate. Examples of 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. Among these, an isocyanate compound blocked with an active methylene compound is preferable from the viewpoint that it is particularly effective for reducing the migration of the adhesive layer to the adherend.

  In addition, the isocyanate compound 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 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.

  Of the above, polyether epoxy compounds are preferable from the viewpoint of good adhesive properties. Further, the amount of the epoxy group is preferably a polyepoxy compound having a polyfunctionality of 3 or more rather than a bifunctional.

  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 improves and it becomes easy to adjust an adhesive characteristic.

  The carbodiimide compound is a compound having one or more carbodiimide or carbodiimide derivative structures in the molecule. A polycarbodiimide compound having two or more molecules in the molecule is more preferable for better adhesive layer strength 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.

  A silane coupling compound is an organosilicon compound having an organic functional group and a hydrolysis group such as an alkoxy group in one molecule. For example, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4- Epoxy group) epoxy group-containing compounds such as ethyltrimethoxysilane, vinyl group-containing compounds such as vinyltrimethoxysilane and vinyltriethoxysilane, styryl group-containing compounds such as p-styryltrimethoxysilane and p-styryltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, etc. (Meth) acrylic group-containing compound, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl)- 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N -Amino group-containing compounds such as (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, tris (trimethoxysilylpropyl) Isocyanurate, tris (triethoxysilylpropyl) Examples include isocyanurate group-containing compounds such as cyanurate, mercapto group-containing compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane. It is done.

  Among the above compounds, from the viewpoint of maintaining the strength and adhesive strength of the adhesive layer, epoxy group-containing silane coupling compounds, double bond-containing silane coupling compounds such as vinyl groups and (meth) acryl groups, amino group-containing silane couplings Compounds are more preferred.

  These cross-linking agents are used in a design for improving the performance of the pressure-sensitive adhesive layer by reacting in the drying process or the film forming process. It can be inferred that unreacted products of these crosslinking agents, compounds after the reaction, or a mixture thereof exist in the resulting adhesive layer.

  In addition, the number of carbon atoms is 4 or more from the viewpoints of appearance of the adhesive layer, adjustment of adhesive strength, reinforcement of the adhesive layer, adhesion to the base film, blocking resistance, and prevention of migration of the adhesive component to the adherend. It is also possible to use a resin other than a (meth) acrylic resin having a (meth) acrylate unit having an alkyl group at the ester end of 20% by weight or more. As the resin, conventionally known materials can be used. For example, (meth) acrylic resin, polyester resin, urethane resin and polyvinyl (polyvinyl alcohol, vinyl chloride vinyl acetate copolymer, etc.) not corresponding to the above are used. In view of the influence on the appearance and adhesive strength of the adhesive layer, a resin selected from (meth) acrylic resins, polyester resins and urethane resins is more preferable. However, depending on the method of use, there is a concern that the adhesive strength may be greatly reduced, and caution is required. In order not to greatly reduce the adhesive strength, it may be preferable to use a resin having a low glass transition point, for example, a resin having a temperature of 0 ° C. or lower. Conversely, in order to reduce the migration of the adhesive component to the adherend, it may be preferable to use a resin having a relatively high glass transition point. For example, a resin having a glass transition point exceeding 0 ° C. It may be preferable to use together.

  In forming the adhesive layer, it is also possible to use particles in combination for blocking, improving slipperiness and adjusting adhesive properties. However, care should be taken because the adhesive strength may decrease depending on the type of particles used. In order not to reduce the adhesive strength so much, it is preferable that the average particle size of the particles used is 3 times or less the thickness of the adhesive layer, more preferably 1.5 times or less, and even more preferably 1.0 times or less. Particularly preferably, the range is 0.8 times or less. In particular, when it is desired to exhibit the adhesive performance of the resin of the adhesive layer as it is, it may be preferable not to contain particles in the adhesive layer.

A functional layer may be provided on the surface of the film opposite to the adhesive layer for various functions.
For example, it is preferable to provide a release layer in order to reduce blocking of the film by the adhesive layer, and in order to prevent defects due to adhesion of dust around the film due to film peeling or frictional charging, an antistatic layer is provided. Providing is also a preferred form. The functional layer may be provided by coating, may be provided by in-line coating, or may employ offline coating. In-line coating is preferably used from the viewpoint of stabilization of production cost, release performance by in-line heat treatment, antistatic performance, and the like.

  For example, when a release functional layer is provided on the surface opposite to the adhesive layer of the film, the release agent contained in the functional layer is not particularly limited, and conventionally known release agents can be used. Yes, for example, long-chain alkyl group-containing compounds, fluorine compounds, silicone compounds, waxes and the like. 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. Also, wax is effective for improving the surface decontamination property. 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 in 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 functional 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 functional 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 0.000 in terms of a molar ratio, where the siloxane bond of the silicone is 1. It is in the range of 20%, more preferably in the range of 0.03 to 0.15%, particularly preferably in the range of 0.05 to 0.12%. By using within this range, it is possible to maintain the dispersibility in water, the durability of the functional layer, and the 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 high in consideration of the durability and release performance of the functional 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 temporal change and release performance of the functional layer and the contamination of various processes, it is preferable that the low molecular component (number average molecular weight is 500 or less) of silicone 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, silicon-bonded vinyl groups (vinyl silane) and hydrogen groups (hydrogen silane) can cause changes in performance over time if left unreacted in the functional 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 polymers other than the polyether group-containing silicone that can be used for forming the functional layer, anionic dispersants and nonionic dispersants 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. Examples of synthetic hydrocarbons include Fischer-Tropsch wax (also known as sazol wax) and polyethylene wax, and other low molecular weight polymers (specifically, polymers having a number average molecular weight of 500 to 20000). The following polymers are also exemplified: 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 number average 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.

  When providing an antistatic functional layer on the surface opposite to the adhesive layer of the film, the antistatic agent contained in the functional layer is not particularly limited, and conventionally known antistatic agents can be used. A polymer type antistatic agent is preferred because of its good heat resistance and moist heat resistance. Examples of the polymer type antistatic agent include a compound having an ammonium group, a polyether compound, a compound having a sulfonic acid group, a betaine compound, and a conductive polymer.

  The compound having an ammonium group is a compound having an ammonium group in the molecule, and examples thereof include aliphatic amines, alicyclic amines, and ammonium compounds of aromatic amines. The compound having an ammonium group is preferably a compound having a polymer type ammonium group, and the ammonium group has a structure incorporated in the main chain or side chain of the polymer, not as a counter ion. It is preferable. For example, a polymer obtained by polymerizing a monomer containing an addition polymerizable ammonium group or a precursor of an ammonium group such as an amine is used as a polymer compound having an ammonium group, which is preferably used. As the polymer, a monomer containing an addition polymerizable ammonium group or a precursor of an ammonium group such as an amine may be polymerized alone, or it may be a copolymer of a monomer containing these and another monomer. May be.

  Among the compounds having an ammonium group, compounds having a pyrrolidinium ring are also preferred in that they are excellent in antistatic properties and heat stability.

The two substituents bonded to the nitrogen atom of the compound having a pyrrolidinium ring are each independently an alkyl group, a phenyl group, and the like. Even if these alkyl groups and phenyl groups are substituted with the groups shown below, Good. Substitutable groups are, for example, hydroxyl group, amide group, ester group, alkoxy group, phenoxy group, naphthoxy group, thioalkoxy, thiophenoxy group, cycloalkyl group, trialkylammonium alkyl group, cyano group, and halogen. Moreover, the two substituents bonded to the nitrogen atom may be chemically bonded. For example, — (CH ₂ ) _m — (m = 2 to 5), —CH (CH ₃ ) CH (CH ₃ ) —, —CH═CH—CH═CH—, —CH═CH—CH═N—, —CH═CH—N═C—, —CH ₂ OCH ₂ —, — (CH ₂ ) ₂ O (CH ₂ ) ₂ — and the like.

  A polymer having a pyrrolidinium ring can be obtained by cyclopolymerizing a diallylamine derivative using a radical polymerization catalyst. The polymerization is carried out by using a polymerization initiator such as hydrogen peroxide, benzoyl peroxide, tertiary butyl peroxide in a polar solvent such as water or methanol, ethanol, isopropanol, formamide, dimethylformamide, dioxane, acetonitrile as a solvent. Although it can implement by a method, it is not limited to these. In the present invention, a compound having a diallylamine derivative and a polymerizable carbon-carbon unsaturated bond may be used as a copolymerization component.

  Moreover, it is also preferable that it is a polymer which has a structure of following formula (1) at the point which is excellent in antistatic property and wet heat-resistant stability. A single polymer or copolymer, or a plurality of other components may be copolymerized.

For example, in the above formula, the substituent R ¹ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, a hydrocarbon group such as a phenyl group, R ² is —O—, —NH— or —S—, and R ³ is R ¹ , R ⁵ , R ⁶ each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a phenyl group. Or a hydrocarbon group provided with a functional group such as a hydroxyalkyl group, and X ⁻ represents various counter ions.

Among these, from the viewpoint of excellent antistatic properties and wet heat resistance, in particular, in the formula (1), the substituent R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ³ is preferably an alkyl group having 1 to 6 carbon atoms, and R ⁴ , R ⁵ and R ⁶ are preferably each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably , R ⁴ , R ⁵ , or R ⁶ is a hydrogen atom, and the other substituent is an alkyl group having 1 to 4 carbon atoms.

  Examples of the anion serving as the counter ion (counter ion) of the ammonium group of the compound having an ammonium group described above include ions such as halogen ions, sulfonates, phosphates, nitrates, alkylsulfonates, and carboxylates.

Moreover, the number average molecular weight of the compound which has an ammonium group is 1000-500000, Preferably it is 2000-350,000, More preferably, it is 5000-200000. When the molecular weight is less than 1000, the strength of the coating film may be weakened or the heat stability may be poor.
On the other hand, when the molecular weight exceeds 500,000, the viscosity of the coating solution increases, and the handleability and applicability may deteriorate.

  Examples of polyether compounds include polyethylene oxide, polyether ester amide, acrylic resins having polyethylene glycol in the side chain, and the like.

  The compound having a sulfonic acid group is a compound containing a sulfonic acid or a sulfonate in the molecule. For example, a compound having a large amount of sulfonic acid or a sulfonate such as polystyrene sulfonic acid is preferably used. It is done.

  Examples of the conductive polymer include polythiophene-based, polyaniline-based, polypyrrole-based, and polyacetylene-based polymers. Among them, for example, polythiophene-based polymers using poly (3,4-ethylenedioxythiophene) in combination with polystyrene sulfonic acid. Are preferably used. The conductive polymer is preferable to the other antistatic agents described above in that the resistance value is low. However, on the other hand, it is necessary to devise measures such as reducing the amount used in applications where coloring and cost are a concern.

  It is also a preferred embodiment that the functional layer that can be provided on the surface of the film opposite to the adhesive layer contains both the above-mentioned release agent and antistatic agent and has an antistatic release function.

  For the formation of the functional layer, various polymers such as polyester resin, acrylic resin, urethane resin, and a crosslinking agent that can be used for forming the adhesive layer are used in combination to improve the coating appearance, transparency, and control of slipperiness. It is also possible. In particular, in terms of strengthening the functional layer and reducing blocking, it is preferable to use a melamine compound, an oxazoline compound, an isocyanate compound, an epoxy compound, or a carbodiimide compound, 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 functional layer in order to improve blocking and slipperiness. However, when the functional layer has mold release performance, it often has sufficient blocking resistance and slipperiness, and therefore it may be preferable not to use particles from the viewpoint of the appearance of the functional layer.

  Furthermore, in the range not impairing the gist of the present invention, an antifoaming agent, a coating property improving agent, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, Antioxidants, foaming agents, dyes, pigments and the like can be used in combination.

  As a ratio in the pressure-sensitive adhesive layer constituting the laminated polyester film, the (meth) acrylic resin having a (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester terminal is usually 20% by weight or more. The range is preferably 40 to 99.5% by weight, more preferably 55 to 99% by weight, particularly preferably 70 to 97% by weight, and most preferably 75 to 95% by weight. By using in the above range, sufficient adhesive force can be easily obtained, and the adhesive force can be easily adjusted. When the content is too small, the adhesive strength may be reduced, and thus it may be necessary to devise such as increasing the thickness of the adhesive layer. However, in order to increase the film thickness, care must be taken because the productivity may be adversely affected, for example, by reducing the line speed depending on the degree or circumstances.

  As a ratio in the adhesive layer constituting the laminated polyester film, the crosslinking agent is preferably 60% by weight or less, more preferably 0.9 to 40% by weight, still more preferably 2 to 29% by weight, and particularly preferably 7 to 20%. It is in the range of wt%. By using in the said range, while improving the intensity | strength of an adhesion layer and the transfer to the adherend of an adhesion layer, it is easy to adjust adhesive force. If the content is too small, the transfer to the adherend will increase. Conversely, if the content is too large, the adhesive strength may decrease, so a device such as increasing the thickness of the adhesive layer is required. It may become. However, in order to increase the film thickness, care must be taken because the productivity may be adversely affected, for example, by reducing the line speed depending on the degree or circumstances.

  As a ratio in the adhesive layer constituting the laminated polyester film, the particles are preferably 50% by weight or less, more preferably 0.1 to 40% by weight, still more preferably 0.5 to 20% by weight, and particularly preferably 1 to It is in the range of 15% by weight. By using in the above range, sufficient adhesive properties, anti-blocking properties and slipperiness are easily obtained. However, it should be noted that depending on the composition of the adhesive layer and the type of particles, the adhesive properties may deteriorate if used in large numbers.

  In the laminated polyester film, when providing a functional layer having a releasing performance on the side opposite to the adhesive layer, the proportion of the releasing agent as a proportion in the functional layer is generally different because the appropriate amount varies depending on the type of releasing agent. However, it is preferably in the range of 3% by weight or more, more preferably 15% by weight or more, and further preferably in the range of 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 functional layer is preferably 5% by weight or more, more preferably 15 to 99% by weight, still more preferably 20 to 95% by weight, particularly Preferably it is the range of 25 to 90 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 functional 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 in the range of 10 to 90% by 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, further 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 functional layer is preferably 5% by weight or more, more preferably 25% by weight or more, further preferably 50% by weight or more, and particularly preferably 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 becomes effective and the external appearance of a functional layer also becomes favorable.

  When wax is used as the release agent, the ratio in the functional 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. However, when wax is used for the purpose of decontamination of the surface, the above ratio can be reduced, preferably 1% by weight or more, more preferably 2 to 50% by weight, and further preferably 3 to 30% by weight. % Range. 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.

  On the other hand, when a functional layer having antistatic performance is provided on the side opposite to the adhesive layer, the proportion of the antistatic agent as the proportion in the functional layer cannot be generally described because the appropriate amount varies depending on the type of the antistatic agent. Is preferably in the range of 0.5% by weight or more, more preferably in the range of 3 to 90% by weight, still more preferably in the range of 5 to 70% by weight, and particularly preferably in the range of 8 to 60% by weight. If it is less than 0.5% by weight, the antistatic effect is not sufficient, and the effect of preventing the adhesion of surrounding dust and the like may not be sufficient.

  When an antistatic agent other than a conductive polymer is used as the antistatic agent, the proportion in the antistatic layer is preferably 5% by weight or more, more preferably 10 to 90% by weight, still more preferably 20 to 70% by weight. The range, particularly preferably 25 to 60% by weight. If it is less than 5% by weight, the antistatic effect is not sufficient, and the effect of preventing the adhesion of surrounding dust and the like may not be sufficient.

  When a conductive polymer is used as the antistatic agent, the proportion in the antistatic layer is preferably 0.5% by weight or more, more preferably 3 to 70% by weight, still more preferably 5 to 50% by weight, particularly preferably. It is in the range of 8 to 30% by weight. If it is less than 0.5% by weight, the antistatic effect is not sufficient, and the effect of preventing the adhesion of surrounding dust and the like may not be sufficient.

  The analysis of the components in the adhesive layer and the functional layer can be performed by analysis of TOF-SIMS, ESCA, fluorescent X-ray, IR, etc., for example.

  Regarding the formation of the adhesive layer and functional layer, the above-mentioned series of compounds is used as a solution or solvent dispersion, and the film is coated with a liquid adjusted to a solid content concentration of about 0.1 to 80% by weight. It is preferable to produce a laminated polyester film. In particular, when 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.

  The film thickness of the adhesive layer depends on the material used for the adhesive layer, and cannot be said unconditionally. However, in order to adjust the adhesive force more appropriately, or to improve the blocking property, the appearance of the adhesive layer, etc., 10 μm Hereinafter, it is preferably in the range of 1 nm to 4 μm, more preferably 10 nm to 1 μm, still more preferably 20 to 400 nm, particularly preferably 30 to 300 nm. In addition, in order to reduce the migration of the adhesive component to the adherend, a thinner one is preferable.For example, when there is no material such as a cross-linking agent that reduces the migration, the migration can only be achieved by adjusting the film thickness thinly. Since it cannot be reduced, when it is necessary to reduce the transition, it is preferable that the thickness is 100 nm or less, more preferably 70 nm or less.

  A general adhesive layer has a thickness of several tens of μm, but in such a case, for example, when used for manufacturing a polarizing plate, the adhesive film is used as a polarizing plate, a retardation plate, a viewing angle expansion plate, and the like. When sticking to the adherend and cutting, the sticking out of the pressure-sensitive adhesive layer may occur remarkably.

  However, the protrusion can be minimized by adjusting the film thickness within the above-mentioned range. This effect becomes better as the adhesive layer is thinner. In addition, the thinner the adhesive layer, the smaller the absolute amount of the adhesive layer present on the film, and the more effective the adhesive paste component is transferred to the adherend. Furthermore, it can be seen that by setting the film thickness in the above-mentioned range, it is possible to achieve an appropriate adhesive strength that is not too strong. For example, for polarizing plate manufacturing processes, both adhesive performance and peeling performance that peels after bonding are achieved. When used in applications where it is necessary to achieve this, the adhesive-peeling operation can be easily performed, and an optimum film can be obtained.

  The thinner the film is, the more effective it is for blocking properties, and it is easier to manufacture when forming an adhesive layer by in-line coating. On the other hand, if the film thickness is too thin, the adhesive properties may vary depending on the configuration of the adhesive layer. Since it may disappear, use in the above-mentioned suitable range according to a use is preferable.

  Although the thickness of the functional layer depends on the function to be provided, it cannot be said unconditionally. For example, the functional layer for imparting release performance or antistatic performance is preferably 1 nm to 3 μm, more preferably It is in the range of 10 nm to 1 μm, more preferably 20 to 500 nm, particularly preferably 20 to 200 nm. By using the film thickness of the functional layer within the above range, it becomes easy to improve the blocking characteristics, improve the antistatic performance, or obtain a good appearance.

  Examples of methods for forming the adhesive layer and functional layer include gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, and impregnation. Conventionally known coating methods such as coat, kiss coat, spray coat, calendar coat, and extrusion coat can be used.

  The drying and curing conditions for forming the adhesive layer on the film are not particularly limited, but in the case of the coating method, the drying of a solvent such as water used in the coating solution is preferably 70. 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 adhesion 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 processing 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 film constituting the laminated polyester film in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  As the adhesive strength of the adhesive layer, the adhesive strength with respect to the polymethylmethacrylate plate measured by the measurement method described later is usually 1 mN / cm or more, preferably 3 to 3000 mN / cm, more preferably 5 to 500 mN / cm. More preferably, it is in the range of 7 to 300 mN / cm, particularly preferably 10 to 100 mN / cm. By using it in the above range, the adhesion to the adherend becomes good. Moreover, by adjusting moderately, it will become easy to stick and peel and will also prevent blocking of a film.

  The arithmetic average roughness (Sa) of the adhesive layer surface is preferably 50 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less, particularly preferably 15 nm or less, and most preferably 10 nm or less. If Sa is too high, sufficient adhesive strength may not be exhibited. Moreover, when Sa is too high, in order to express adhesive force, it may be necessary to adjust the film thickness of the adhesive layer to be thick, and adjustment of adhesive force and reduction of the transfer of adhesive components to the adherend may be reduced. It can be difficult. The lower limit is not particularly limited, but the lower limit of the preferred range is 1 nm.

  Sa on the surface of the adhesive layer can be adjusted by designing the adhesive layer or designing the polyester film layer on the side in contact with the adhesive layer. When trying to adjust Sa in the design of the pressure-sensitive adhesive layer, it is necessary to increase the thickness of the pressure-sensitive adhesive layer and raise the hurdle in designing the pressure-sensitive adhesive force. Therefore, it is preferable to cope with the design of the polyester film layer.

  As a design of the polyester film layer on the adhesive layer side, the average particle diameter of the contained particles, the content of the particles, and the thickness of the polyester film layer are mainly mentioned as factors affecting Sa. Since the value of Sa is mainly determined by the interrelationship of these factors, it is not possible to determine the value of Sa considering only one factor. However, as a guideline for adjustment, the average particle size of the particles is preferably 5 μm or less. More preferably, it is a range of 3.5 μm or less. By using in the said range, it becomes easy to make Sa low.

  The amount of particles contained in the polyester film layer on the adhesive layer side is preferably less than 0.30% by weight, more preferably 0.15% by weight or less, still more preferably 0.10% by weight or less, particularly preferably 0.08. It is in the range of weight percent or less. By using in the said range, it becomes easy to make Sa low.

  The layer thickness of the polyester film layer on the adhesive layer side is preferably in the range of 0.5 to 10 μm, more preferably 1 to 8 μm, and still more preferably 2 to 6 μm. By using in the said range, it becomes easy to adjust content of particle | grains and adjustment of Sa also becomes easy.

As described above, Sa on the adhesive layer surface depends on the design of the adhesive layer, so it cannot be said unconditionally. However, the Sa of the polyester surface from which the adhesive layer has been removed (polyester surface when the adhesive layer is not formed) is preferably The range is 50 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less, particularly preferably 15 nm or less, and most preferably 10 nm or less.
By using in the said range, it will become easier to adjust Sa of the adhesion layer surface.

As the blocking property of the laminated polyester film, the adhesive layer side surface and the opposite side surface (functional layer side surface when there is a functional layer) are overlapped, and 40 ° C., 80% RH, 10 kg / cm ² , 20 hours. The peeling load after pressing under conditions is preferably 100 g / cm or less, more preferably 30 g / cm or less, further preferably 20 g / cm or less, particularly preferably 10 g / cm or less, and most preferably 8 g / cm or less. It is a range. By setting it as the said range, it becomes easy to avoid the risk of blocking and it can be set as a more practical film.

For applications requiring antistatic properties as a laminated polyester film, the surface resistance value of the functional layer is preferably 1 × 10 ¹² Ω or less, more preferably 1 × 10 ¹¹ Ω or less, and even more preferably 5 × 10 ^10. The range is Ω or less. When it is within the above range, the film has little adhesion of dust and the like.

  Further, roughening the film surface on the side opposite to the pressure-sensitive adhesive layer (the side of the functional layer when there is a functional layer) may be one of the means for improving the blocking property with the pressure-sensitive adhesive layer. . Since it depends on the type and adhesive strength of the adhesive layer, it cannot be said unconditionally. However, if there is a purpose to improve the blocking characteristics by surface roughness, regardless of the functional layer, the film surface on the side opposite to the adhesive layer The arithmetic average roughness (Sa) is preferably 5 nm or more, more preferably 8 nm or more, and further preferably 30 nm or more. The upper limit is not particularly limited, but the upper limit of the preferred range is 300 nm from the viewpoint of transparency. It is. In addition, when the releasability is good by a method such as providing a release functional layer on the side surface opposite to the adhesive layer, the releasability becomes dominant, so the influence of Sa is small and no special attention is required. However, when the releasability is weak, the influence of Sa may become large, which can be an effective means for improving the blocking characteristics. However, if Sa is increased, the haze increases and the transparency is lowered. Therefore, it is necessary to take measures according to the application, and it is preferable to consider the blocking improvement by the release layer particularly in a case where transparency is important. .

  As the haze of the laminated polyester film, when confirmation or inspection is performed in a state of being bonded to the adherend, the haze value is preferably low, preferably 5.0% or less, more preferably 3.0. % Or less, more preferably 2.0% or less, particularly preferably 1.5% or less, and most preferably 1.0% or less. It is preferable that the haze is lower when inspecting foreign matter or the like with a machine than with visual confirmation. The lower limit is not particularly limited, but a preferable range is 0.1%. Since visibility and straightness of light are improved by using in the above range, the state of the adherend can be grasped without removing the polyester film as the protective film even when various inspections and confirmations are required. .

  Polyolefin films, which are conventional surface protection films, have high haze (exceeding about 10%, etc.) and inferior in transparency, so it is sufficient to inspect the adherend with the surface protection film attached. It can not be done, it takes time and labor to peel off the surface protection film to inspect the adherend, and further, there is a risk of causing defects such as adhesion of foreign objects and scratches when peeled off, In some cases, a surface protective film having low haze and high transparency that can inspect the adherend in a state where the surface protective film is bonded is required.

  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) Method for Measuring Arithmetic Average Roughness (Sa) Using a non-contact surface / layer cross-sectional shape measurement system VertScan (registered trademark) R550GML manufactured by Ryoka System Co., Ltd., a CCD camera: SONY HR- 50 1/3 ′, objective lens: 20 ×, lens barrel: 1 × Body, zoom lens: No Relay, wavelength filter: 530 white, measurement mode: Wave, and output by fourth-order polynomial correction was used.

(4) Method for Measuring Film Thickness of Adhesive Layer and Functional Layer The surface of the adhesive layer or functional layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by ultramicrotomy stained with RuO _4, and the adhesive layer cross-section was measured using a TEM (Hitachi High Technologies Corporation H-7650, accelerating voltage 100 V).

(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) Measuring method of haze It measured by JISK7136 using the haze meter HM-150 by Murakami Color Research Laboratory.

(8-1) Adhesive strength evaluation method (adhesive strength 1)
The pressure-sensitive adhesive layer surface of the laminated polyester film of the present invention having a width of 5 cm is applied to the surface of a polymethylmethacrylate plate (Kuraray Co., Ltd. (commercial glass (registered trademark), 1 mm thick)) with a 2 cm rubber roller having a width of 5 cm, The peel force after standing for 1 hour 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.

(8-2) Adhesive strength evaluation method (adhesive strength 2)
(8-1) except that the adhesive strength was evaluated using the polyester film surface (thickness 25 μm) having no adhesive layer obtained in Comparative Example 1 described later instead of the polymethyl methacrylate plate (8-1). ) And evaluation was performed in the same manner.

(9) Measuring method of blocking property Two polyester films to be measured are prepared, and the adhesive layer side and the opposite side of the adhesive layer (the functional layer side when there is a functional layer) are overlapped to obtain an area of 12 cm × 10 cm Was pressed under the conditions of 40 ° C., 80% RH, 10 kg / cm ² , and 20 hours. Thereafter, the films were peeled according to the method specified in ASTM D1893, and the peel load was measured.
The lighter the peeling load, the harder it is to block and the better, preferably 100 g / cm or less, more preferably 30 g / cm or less, more preferably 20 g / cm or less, particularly preferably 10 g / cm or less, and most preferably 8 g / cm. The range is as follows. In addition, it described as "-" when sufficient measurement cannot be performed exceeding 300 g / cm, or when a film fractures | ruptures.

(10) Evaluation Method of Adhesive Layer Base Material Adhesion Layer The adhesive layer side of one A4 size laminated polyester film and the A4 size polyester film without the adhesive layer of Comparative Example 1, which will be described later, are layered and pressed firmly with fingers. After the film is pasted, the film having the adhesive layer is peeled off, and the film surface without the adhesive layer of Comparative Example 1 is observed, and when there is no adhesive residue (transferred trace of the adhesive layer) (the adhesive layer and the original substrate) A) when adhesiveness is good, and B when adhesive residue is present (when the adhesiveness of the adhesive layer is poor).

(11) Method for evaluating transparency after being attached to an adherend On the surface of a polymethylmethacrylate plate (Kuraray Co., Ltd., Como Glass (registered trademark), thickness 1 mm), the laminated polyester film of the present invention having a width of 5 cm is provided. The pressure-sensitive adhesive layer surface was pressure-bonded twice with a 2 kg rubber roller having a width of 5 cm, and the appearance after pasting was visually observed from the side of the laminated polyester film.
A is clear when the polymethyl methacrylate plate can be observed clearly, A is slightly grainy, but there is enough transparency, B when the polymethyl methacrylate plate can be observed, B The case where the methacrylate plate could be observed sufficiently was designated as C, and the case where it was cloudy and the polymethyl methacrylate plate could not be observed sufficiently was designated as D.

(12) Method for evaluating transferability of adhesive layer to adherend Adhesion of laminated polyester film of the present invention having a width of 5 cm to the surface of a polymethyl methacrylate plate (Kuraray Co., Ltd., Como Glass (registered trademark), thickness 1 mm) The layer surface was subjected to two reciprocating pressure bonding with a 2 cm rubber roller having a width of 5 cm, followed by attachment, treatment at 60 ° C. for 8 days, the film was peeled off, and the surface of the polymethyl methacrylate plate was observed.
A when there is no trace on the polymethylmethacrylate plate (no migration of the adhesive layer), B when a very thin trace is observed when staring for 3 seconds under a fluorescent lamp, and a thin trace The case where C is observed, the case where clear white marks are partially observed such as the edge where the film is attached (the adhesive layer has moved) D, the case where clear white marks are observed over the entire surface E. In addition, when not sticking to a to-be-adhered body, it described as "-". In applications where transferability is a concern, it is better to avoid D and E, and in applications where low transferability is required, it is preferable that the level is A or B, particularly A.

(13) Measuring method of surface resistance Using a high resistance measuring instrument made by Nippon Hewlett-Packard Co., Ltd .: HP4339B and measuring electrode: HP16008B, the polyester film is fully conditioned in a measurement atmosphere of 23 ° C. and 50% RH, and then applied. The surface resistance of the antistatic layer after 1 minute at a voltage of 100 V was measured.

(14) Dust adhesion evaluation method on the functional layer (antistatic layer) side After sufficiently conditioning the polyester film in a measurement atmosphere of 23 ° C. and 50% RH, the antistatic layer is rubbed 10 times with a cotton cloth. This was brought close to the finely crushed cigarette ash and the ash adhesion was evaluated according to the following criteria.
A: Does not adhere even when the film is brought into contact with ash. B: A little sticks when the film is brought into contact with ash.

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 polyester (A), polyester (C) is obtained using the same method as the production method of polyester (A) except that 0.3 part by weight of silica particles having an average particle diameter of 2 μm is added before melt polymerization. It was.

<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 0.6 parts by weight of silica particles having an average particle diameter of 3.2 μm is added before the melt polymerization. Got.

Examples of compounds constituting the adhesive layer and the functional layer are as follows.
(Example compounds)
・ (Meth) acrylic resin: (IA)
Aqueous dispersion of acrylic resin (glass transition point: −50 ° C.) having the following composition: 2-ethylhexyl acrylate / methyl methacrylate / methacrylic acid = 85/12/3 (% by weight)
・ (Meth) acrylic resin: (IB)
Aqueous dispersion of acrylic resin (glass transition point: −55 ° C.) having the following composition: 2-ethylhexyl acrylate / normal butyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate = 77/10/5/8 (% by weight)
・ (Meth) acrylic resin: (IC)
Aqueous dispersion of acrylic resin (glass transition point: −25 ° C.) having the following composition Normal butyl acrylate / styrene / acrylic acid = 62/35/3 (% by weight)
・ (Meth) acrylic resin: (ID)
Aqueous dispersion of acrylic resin (glass transition point: −40 ° C.) having the following composition: 2-ethylhexyl acrylate / normal butyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate / acrylic acid = 58/20/15/5 / 2 (% by weight)
・ (Meth) acrylic resin: (IE)
Aqueous dispersion of acrylic resin (glass transition point: −40 ° C.) having the following composition: normal butyl acrylate / 2-ethylhexyl acrylate / acrylonitrile / acrylic acid = 82/10/5/3 (% by weight)
・ (Meth) acrylic resin: (IF)
Aqueous dispersion of acrylic resin (glass transition point: −50 ° C.) having the following composition: 2-ethylhexyl acrylate / normal butyl acrylate / ethyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 50/27/15/5 / 3 (% by weight)
・ (Meth) acrylic resin: (IG)
Aqueous dispersion of acrylic resin (glass transition point: 10 ° C.) having the following composition: normal butyl acrylate / ethyl acrylate / methyl methacrylate / 2-hydroxyethyl methacrylate / acrylic acid = 10/52/30/5/3 (% by weight)
・ (Meth) acrylic resin: (IH)
Aqueous dispersion of acrylic resin (glass transition point: 40 ° C.) having the following composition: ethyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 48/45/4/3 (% by weight)

Melamine compound: (IIA) hexamethoxymethylol melamine

・ Isocyanate compounds: (IIB)
1000 parts of hexamethylene diisocyanate was stirred at 60 ° C., and 0.1 part of tetramethylammonium caprylate 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.

・ Oxazoline compounds: (IIC)
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.)

Epoxy compound: (IID) Polyglycerol polyglycidyl ether, which is a polyfunctional polyepoxy compound

・ Polyester resin: (IIIA)
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: (IIIB)
Water dispersion of polyester resin (glass transition point: 50 ° 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 = 50/46/4 // 70/20/10 (mol%)

-Urethane resin: (IIIC)
Polyurethane polyol having a number average molecular weight of 2000 / polyethylene glycol / methylene bis (4) having a number average molecular weight of 400 comprising an aqueous dispersion of 1,6-hexanediol and diethyl carbonate having a urethane resin (glass transition point: −30 ° C.) having the following composition: -Cyclohexyl isocyanate) / dimethylolbutanoic acid = 80/4/12/4 (% by weight)

-Urethane resin: (IIID)
Water dispersion of urethane resin (glass transition point: 50 ° C.) having the following composition: Isophorone diisocyanate / terephthalic acid / isophthalic acid / ethylene glycol / diethylene glycol / dimethylolpropanoic acid = 12/19/18/21/25/5 (mol) %)

-Particles: (IV) Silica particles with an average particle size of 45 nm

・ Release agent (long chain alkyl group-containing compound): (VA)
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): (VB)
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: (VC)
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.

・ Wax: (VD)
An emulsification facility with an internal capacity 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, number average molecular weight 5000 polyethylene oxide wax 300 g, ion-exchanged water 650 g After adding 50 g of decaglycerin monooleate surfactant and 10 g of 48% potassium hydroxide aqueous solution and replacing with nitrogen, the mixture was sealed, stirred at 150 ° C. for 1 hour at high speed, cooled to 130 ° C., and a high-pressure homogenizer at 400 atm. A wax emulsion passed through and cooled to 40 ° C.

・ Antistatic agent (quaternary ammonium salt compound): (VIA)
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.

・ Antistatic agent (compound having ammonium group): (VIB)
A polymer compound having a number average molecular weight of 50000, wherein the counter ion is a methanesulfonic acid ion, comprising a structural unit of the following formula (2).

Example 1:
A mixed raw material in which polyesters (A), (B), and (C) were mixed in proportions of 91%, 3%, and 6%, 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 3.3 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 to the film thickness of the adhesive layer (dried) on one side of the film. (After) is applied to 120 nm, and coating liquid B1 shown in Table 2 below is applied to the opposite surface so that the film thickness (after drying) of the functional layer is 30 nm, and guided to a tenter at 90 ° C. After drying for 10 seconds, the film was stretched 4.3 times in the transverse direction at 110 ° C., heat treated at 230 ° C. for 10 seconds, and then relaxed by 2% in the transverse direction. The thickness was 25 μm, the adhesive layer side, and the adhesive layer A polyester film having a Sa of 9 nm on the back side (functional layer side) was obtained. When the adhesive layer was removed with ethyl acetate, Sa on the polyester surface side where the adhesive layer was present was 9 nm.

  When the completed polyester film was evaluated, the adhesive strength with the polymethyl methacrylate plate was 16 mN / cm, the adhesive properties were good, and the substrate adhesion was also good. The properties of this film are shown in Table 3 below.

Examples 2-129:
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. The finished polyester film had good adhesive strength and good substrate adhesion as shown in Tables 3 to 8 below.

Example 130:
A mixed raw material in which polyesters (A), (B), and (D) were mixed at a ratio of 87%, 3%, and 10%, 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 with a layer structure of layers (surface layer / intermediate layer / surface layer = discharging amount of 6: 13: 6) and cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.3 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 to the film thickness of the adhesive layer (dried) on one side of the film. (After) is applied to 150 nm, and coating liquid B1 shown in Table 2 below is applied to the opposite side so that the film thickness (after drying) of the functional layer is 30 nm, and guided to a tenter at 90 ° C. After drying for 10 seconds, the film was stretched 4.3 times in the transverse direction at 110 ° C., heat treated at 230 ° C. for 10 seconds, and then relaxed by 2% in the transverse direction. The thickness was 25 μm, the adhesive layer side, and the adhesive layer A polyester film having a Sa of 15 nm on the back surface side (functional layer side) was obtained. When the adhesive layer was removed with ethyl acetate, Sa on the polyester surface on the side where the adhesive layer was present was 15 nm.

  When the completed polyester film was evaluated, the adhesive strength with the polymethyl methacrylate plate was 20 mN / cm, the adhesive properties were good, and the substrate adhesion was also good. The characteristics of this film are shown in Table 8 below.

Example 131:
A polyester film was obtained in the same manner as in Example 130 except that the functional layer was not provided in Example 130. As shown in Table 8 below, the completed polyester film had good adhesive strength and good substrate adhesion.

Example 132:
A mixed raw material obtained by mixing polyesters (A), (B), and (C) at a ratio of 91%, 3%, and 6%, respectively, is used as a raw material for the outermost layer (surface layer 1), and polyesters (A), (B), ( D) was mixed at a ratio of 82%, 3%, and 15%, respectively, as a raw material for the outermost layer (surface layer 2), and polyesters (A) and (B) were mixed at a ratio of 97% and 3%, respectively. Each of the mixed raw materials is used as a raw material for the intermediate layer, and each is supplied to two extruders, melted at 285 ° C., and then on a cooling roll set at 40 ° C., three types and three layers (surface layer 1 / intermediate layer / surface layer 2 = 6: 13: 6 discharge amount) was coextruded and cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.3 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 to the surface layer 1 side of the longitudinally stretched film. (After drying) is applied to 150 nm, and coating liquid B1 shown in Table 2 below is applied to the opposite side so that the film thickness (after drying) of the functional layer is 30 nm and guided to a tenter. After drying at 110 ° C. for 10 seconds, the film was stretched 4.3 times at 110 ° C. in the transverse direction, heat-treated at 230 ° C. for 10 seconds, relaxed 2% in the transverse direction, 25 μm thick, and the surface on the adhesive layer side A polyester film having a Sa of 9 nm and a Sa of the surface of the back surface side (surface layer 2 side, functional layer side) of the adhesive layer of 20 nm was obtained. When the adhesive layer was removed with ethyl acetate, Sa on the polyester surface side where the adhesive layer was present was 9 nm.

  When the completed polyester film was evaluated, the adhesive strength with the polymethyl methacrylate plate was 22 mN / cm, the adhesive properties were good, and the substrate adhesion was also good. The characteristics of this film are shown in Table 8 below.

Example 133:
A polyester film was obtained in the same manner as in Example 132 except that the functional layer was not provided. As shown in Table 8 below, the completed polyester film had good adhesive strength and good substrate adhesion.

Example 134:
A mixed raw material obtained by mixing polyesters (A), (B), and (C) at a ratio of 91%, 3%, and 6%, respectively, is used as a raw material for the outermost layer (surface layer 1), and polyesters (A), (B), ( D) was mixed at a ratio of 72%, 3%, and 25%, respectively, as a raw material for the outermost layer (surface layer 2), and polyesters (A) and (B) were mixed at a ratio of 97% and 3%, respectively. Each of the mixed raw materials is used as a raw material for the intermediate layer, and each is supplied to two extruders, melted at 285 ° C., and then on a cooling roll set at 40 ° C., three types and three layers (surface layer 1 / intermediate layer / surface layer 2 = 6: 13: 6 discharge amount) was coextruded and cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.3 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 to the surface layer 1 side of the longitudinally stretched film. (After drying) is applied to 150 nm, and coating liquid B1 shown in Table 2 below is applied to the opposite side so that the film thickness (after drying) of the functional layer is 30 nm and guided to a tenter. After drying at 110 ° C. for 10 seconds, the film was stretched 4.3 times at 110 ° C. in the transverse direction, heat-treated at 230 ° C. for 10 seconds, relaxed 2% in the transverse direction, 25 μm thick, and the surface on the adhesive layer side A polyester film having a Sa of 9 nm and a Sa of the surface of the back side (surface layer 2 side, functional layer side) of the adhesive layer of 30 nm was obtained. When the adhesive layer was removed with ethyl acetate, Sa on the polyester surface side where the adhesive layer was present was 9 nm.

  When the completed polyester film was evaluated, the adhesive strength with the polymethyl methacrylate plate was 22 mN / cm, the adhesive properties were good, and the substrate adhesion was also good. The characteristics of this film are shown in Table 8 below.

Example 135:
In Example 134, it manufactured similarly to Example 134 except not having provided the functional layer, and obtained the polyester film. As shown in Table 8 below, the completed polyester film had good adhesive strength and good substrate adhesion.

Example 136:
A mixed raw material obtained by mixing polyesters (A), (B), and (C) at a ratio of 91%, 3%, and 6%, respectively, is used as a raw material for the outermost layer (surface layer 1), and polyesters (A), (B), ( D) was mixed at a ratio of 47%, 3%, and 50%, respectively, as a raw material for the outermost layer (surface layer 2), and polyesters (A) and (B) were mixed at a ratio of 97% and 3%, respectively. Each of the mixed raw materials is used as a raw material for the intermediate layer, and each is supplied to two extruders, melted at 285 ° C., and then on a cooling roll set at 40 ° C., three types and three layers (surface layer 1 / intermediate layer / surface layer 2 = 4: 17: 4 discharge amount) was coextruded and cooled and solidified to obtain an unstretched sheet. Next, the film was stretched 3.3 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 to the surface layer 1 side of the longitudinally stretched film. After coating to 150 nm (after drying), guiding to a tenter, drying at 90 ° C. for 10 seconds, stretching 4.3 times at 110 ° C. in the transverse direction, and performing heat treatment at 230 ° C. for 10 seconds The polyester film was relaxed by 2% in the lateral direction, had a thickness of 25 μm, the surface layer Sa on the adhesive layer side was 9 nm, and the surface Sa on the back surface side of the adhesive layer was 55 nm. When the adhesive layer was removed with ethyl acetate, Sa on the polyester surface side where the adhesive layer was present was 9 nm.

  When the completed polyester film was evaluated, the adhesive strength with the polymethyl methacrylate plate was 22 mN / cm, the adhesive properties were good, and the substrate adhesion was also good. The characteristics of this film are shown in Table 8 below.

Comparative Example 1:
In Example 1, it manufactured like Example 1 except not having provided an adhesion layer and a functional layer, and obtained a polyester film. When the completed polyester film was evaluated, as shown in Table 9 below, it was a film having no adhesive force.

Comparative Examples 2-6:
In Example 1, it manufactured similarly to Example 1 except having changed the coating agent composition into the coating agent composition shown in Table 1, and obtained the polyester film. The finished polyester film was a film having no adhesive strength as shown in Table 9.

Comparative Example 7:
In Example 1, it manufactured similarly to Example 1 except having not provided the adhesion layer, and obtained the polyester film. On the polyester film without the adhesive layer, the coating solution A9 shown in Table 1 below is applied so that the thickness (after drying) of the adhesive layer is 150 nm, dried at 100 ° C. for 60 seconds, and subjected to offline coating. A polyester film having an adhesive layer laminated thereon was obtained. The completed polyester film had good adhesive strength as shown in Table 9. However, the substrate adhesion was poor.

Comparative Example 8:
On the polyester film without the adhesive layer and functional layer obtained in Comparative Example 1, the coating solution A9 shown in Table 1 below was applied at 100 ° C. for 120 seconds so that the thickness (after drying) of the adhesive layer was 20 μm. Drying was performed to obtain a polyester film having an adhesive layer formed by off-line coating. When the polyester film was cut after bonding the pressure-sensitive adhesive layer side, the component of the pressure-sensitive adhesive layer that was not seen in the examples was seen to be contaminated by the pressure-sensitive adhesive component. Also, the adhesive strength could not be measured well. The other characteristics were as shown in Table 9.

  The film of the present invention has few fish eyes in applications such as surface protection films used for preventing scratches and preventing dirt adhesion during transportation, storage and processing of resin plates, metal plates, etc. It can be suitably used for applications that require excellent strength and heat resistance, good adhesive properties, and good substrate adhesion.

The glass transition point of (meth) acrylic resin for improving the adhesive properties, 0 preferably ° C. or less, more preferably -10 ° C. or less, more preferably in the range of -20 ° C. or less, preferably especially the The lower limit of the preferable range is −80 ° C. It becomes easy to set it as the film which has the optimal adhesion characteristic by using in the said range. Moreover, when it is necessary to consider the reduction | decrease of transfer of the adhesion component to a to-be-adhered body, Preferably it is -70 degreeC or more, More preferably, it is -60 degreeC or more, More preferably, it is the range of -50 degreeC or more.

(4) Method for Measuring Film Thickness of Adhesive Layer and Functional Layer The surface of the adhesive layer or functional layer was dyed with RuO ₄ and embedded in an epoxy resin. Thereafter, the section prepared by ultramicrotomy stained with RuO _4, was measured using an adhesive layer cross-sectional TEM (Hitachi High Technologies Corporation H-7650, accelerating voltage 100 k V).

Claims (1)

At least one surface of the polyester film is provided with a coating layer containing a (meth) acrylic resin having a (meth) acrylate unit having an alkyl group having 4 or more carbon atoms at the ester terminal, and having at least one (meth) acrylic resin. A method for producing a laminated polyester film, characterized by forming an adhesive layer by stretching in a direction.