JP6747464B2 - Laminated polyester film - Google Patents

Description

The present invention relates to a laminated polyester film, for example, a resin plate, a metal plate, etc. during transportation, as a surface protection film for preventing scratches and dirt adhesion during storage and processing, etc. The present invention relates to a laminated polyester film having excellent mechanical strength and heat resistance, good adhesive properties, and less migration of an adhesive layer to an adherend.

Conventionally, resin plates, metal plates, glass plates, etc. are protected from scratches and stains during transportation, storage, and processing, and scratches during processing of liquid crystal panels, polarizing plates, and other electronic parts. A wide range of surface protection films are used in applications such as prevention of dust and dirt adhesion, prevention of dirt adhesion during transportation and storage of cars, protection of automobile coating from acid rain, protection of flexible printed circuit boards during plating and etching. It is used.

These surface protective films, such as resin plate, metal plate and glass plate, have appropriate adhesive force to the adherend during transportation, storage or processing of various adherends, It is required that the surface of the adherend is protected by being attached to the surface of the adherend and easily peeled off after the end of the purpose. In order to overcome these problems, it has been proposed to use a polyolefin film for surface protection (Patent Documents 1 and 2).

However, since a polyolefin-based film is used as the surface protection film base material, it is not possible to remove defects caused by gel-like substances and deteriorated products caused by the film base material, which are generally called fish eyes, For example, when inspecting an adherend with the surface protection film attached, there is a problem that a defect of the surface protection film is detected.

Further, as the base material of the surface protection film, a film having a certain degree of mechanical strength is required so that the base material will not be stretched due to tension during various processes such as bonding with an adherend. However, since a polyolefin-based film generally has poor mechanical strength, it has a drawback that it is not suitable for high-tensile processing due to an increase in processing speed in order to emphasize productivity.

Further, even when the processing temperature is increased to improve the processing speed and various characteristics, the polyolefin-based film does not have excellent shrinkage stability due to heat, and thus has poor dimensional stability. Therefore, there is a demand for a film that is less likely to be thermally deformed even when processed at high temperatures 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 its problem to be solved is to use it for various surface protection films and the like, has few fish eyes, is excellent in mechanical strength and heat resistance, and has good adhesive properties. However, it is another object of the present invention to provide a laminated polyester film with less migration of the adhesive layer to the adherend.

The present inventor, as a result of earnest studies in view of the above circumstances, has found that the above-mentioned problems can be easily solved by using a laminated polyester film having a specific configuration, and has completed the present invention.

That is, the gist of the present invention is to have a pressure-sensitive adhesive layer containing a resin having a glass transition point of 0° C. or lower and a crosslinking agent directly on at least one surface of a polyester film, containing a melamine compound as the crosslinking agent, and The laminated polyester film is characterized in that the adhesive strength of the adhesive layer with the polymethylmethacrylate plate is in the range of 1 to 1000 mN/cm, and the film thickness of the adhesive layer is in the range of 1 nm to 440 nm.

According to the laminated polyester film of the present invention, as various surface protective films, a film having less fish eyes, excellent mechanical strength and heat resistance, good adhesive properties, and less migration of the adhesive layer to an adherend. Can be provided, and its industrial value is high.

We believe that it is necessary to significantly change the base material of the base film to reduce fish eyes, improve mechanical strength, and improve heat resistance, and as a result of various studies, it is significantly different from the conventional polyolefin-based materials. It has been found that this can be achieved by using a polyester material. However, by largely changing the material system of the base film, the adhesive property was significantly lowered, and it became impossible to achieve it with a general polyester film. Therefore, the present invention has been achieved by providing an adhesive layer on the substrate film for improvement.
Hereinafter, details of the present invention will be described.

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

The polyester used in the present invention may be a homopolyester or a copolyester. When it is made of homopolyester, it is preferably obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol. 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. Polyethylene terephthalate etc. are illustrated as a typical polyester. On the other hand, examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (eg, p-oxybenzoic acid). One kind or two or more kinds may be mentioned, and the glycol component may be one kind or two or more kinds such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexanedimethanol, neopentyl glycol.

From the viewpoint of forming a film that can withstand various processing conditions, it is preferable that the mechanical strength and heat resistance (dimensional stability by heating) be high, and for that purpose, it may be preferable that the copolymerized polyester component is small. Specifically, the proportion of the monomer forming the copolyester in the polyester film is preferably 10 mol% or less, more preferably 5 mol% or less, and further preferably produced as a by-product during homopolyester polymerization. The amount of diether component is 3 mol% or less. More preferable form of polyester is, in consideration of mechanical strength and heat resistance, among the compounds, a film formed from polyethylene terephthalate or polyethylene naphthalate, which is formed by polymerization from terephthalic acid and ethylene glycol, is more preferable. A film formed of polyethylene terephthalate is more preferable in consideration of ease of use and handleability as a surface protection film.

The polymerization catalyst for polyester is not particularly limited, and conventionally known compounds can be used, and examples thereof include antimony compounds, titanium compounds, germanium compounds, manganese compounds, aluminum compounds, magnesium compounds, calcium compounds and the like. Among these, antimony compounds are preferable because they are inexpensive, and titanium compounds and germanium compounds have high catalytic activity and can be polymerized in a small amount, and since the amount of metal remaining in the film is small, the film Is preferable because it has high transparency. 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, further preferably 2 to 10 ppm. If the content of the titanium compound is too large, the deterioration of the polyester may be accelerated in the step of melt-extruding the polyester to form a yellowish film, and if the content is too small, the polymerization efficiency is poor and the cost is low. In some cases, it is difficult to obtain a film having a sufficient strength or sufficient strength. Further, when a polyester containing a titanium compound is used, it is preferable to use a phosphorus compound to reduce the activity of the titanium compound for the purpose of suppressing deterioration in the melt extrusion step. As the phosphorus compound, orthophosphoric acid is preferable in consideration of the productivity and heat 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 further 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 high, it may cause gelation or foreign matter, and if the content is too low, the activity of the titanium compound cannot be sufficiently lowered, and the yellowish color It may be a film.

Particles may be incorporated into the polyester layer of the film of the present invention for the purpose of imparting slipperiness, preventing scratches in each step, and improving blocking resistance. When the particles are blended, the type of the particles to be blended is not particularly limited as long as they are particles capable of imparting slipperiness, and specific examples include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, and 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, during the polyester manufacturing process, it is also possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed. Among these, silica particles and calcium carbonate particles are preferable because the effect is easily obtained even in a small amount.

The average particle size of the particles is preferably 10 μm or less, more preferably 0.01 to 5 μm, and further preferably 0.01 to 3 μm. When the average particle size exceeds 10 μm, there may be a concern that the film may be deteriorated in transparency.

Further, the content of particles in the polyester layer cannot be generally determined because there is a balance with the average particle size of the particles, but it is preferably 5% by weight or less, more preferably 0.0003 to 3% by weight, and further preferably Is in the range of 0.0005 to 1% by weight. When the content of particles exceeds 5% by weight, problems such as falling of particles and deterioration of transparency of the film may be concerned. When there are no particles or when there are few particles, the slipperiness may be insufficient. Therefore, it may be necessary to take measures such as improving the slipperiness by incorporating particles into the adhesive layer.

The shape of the particles to be used is not particularly limited, and may be spherical, lumpy, rod-shaped, flattened, or the like. Further, the hardness, specific gravity, color, etc. are not particularly limited.
Two or more kinds of these series of particles may be used in combination, if necessary.

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 of producing the polyester constituting each layer, but it is preferably added after the completion of the esterification or transesterification reaction.

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

The thickness of the polyester film is not particularly limited as long as it can be formed into a film, but is preferably in the range of 2 to 350 μm, more preferably 5 to 200 μm, and further preferably 10 to 75 μm.

Although a film production example will be specifically described, the film production method is not limited to the following production examples, and a commonly known film forming method can be adopted. Generally, a resin is melted, formed into a sheet, and stretched for the purpose of increasing the strength and the like to form a film. For example, when producing a biaxially stretched polyester film, first, a polyester raw material is melt-extruded from a die using an extruder, and a molten sheet is cooled and solidified by a cooling roll to obtain an unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to increase the adhesion between the sheet and the rotary cooling drum, and the electrostatic application adhesion method or the liquid application adhesion method is preferably adopted. Next, the obtained unstretched sheet is stretched in one direction by a roll or 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. Then, it is stretched in a direction orthogonal to the stretching direction in the first stage, preferably at 70 to 170° C., and at a stretching ratio of preferably 2.5 to 7 times, more preferably 3.0 to 6 times. A method of obtaining a biaxially oriented film by subsequently performing heat treatment at a temperature of 180 to 270° C. under tension or under relaxation within 30% can be mentioned. In the above stretching, it is possible to employ a method in which stretching in one direction is performed in two or more stages. In that case, it is preferable that the stretching ratios in the two directions finally fall within the above ranges.

Further, in the present invention, the simultaneous biaxial stretching method can be adopted for producing the polyester film constituting the laminated polyester film. The simultaneous biaxial stretching method is a method in which the unstretched sheet is usually stretched and oriented in the machine direction and the width direction at 70 to 120° C., preferably 80 to 110° C. in a temperature controlled state at the same time. Is an area magnification of 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times. Then, subsequently, heat treatment is performed at a temperature of 180 to 270° C. under tension or under relaxation within 30% to obtain a stretched and oriented film. With regard to the simultaneous biaxial stretching device that employs the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be adopted.

Next, the formation of the adhesive layer that constitutes the laminated polyester film in the present invention will be described. Examples of the method for forming the adhesive layer include methods such as coating, transfer and laminating. Considering the ease of forming the adhesive layer, it is preferably formed by coating.

As a method of coating, it may be provided by in-line coating, which is performed in the process of film production, or may be provided by off-line coating, in which the film once produced is coated outside the system. More preferably, it is formed by in-line coating.

Specifically, in-line coating is a method of performing coating at any stage from melt extrusion of a resin forming a film to stretching, stretching, heat setting, and winding. Usually, it is coated on any of an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, and a film before winding after heat setting. Although not limited to the following, for example, in sequential biaxial stretching, a method of coating a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction) and then stretching in the transverse direction is excellent. According to such a method, it is possible to perform film formation and adhesive layer formation at the same time, which is advantageous in terms of manufacturing cost. Further, in order to perform stretching after coating, it is possible to change the thickness of the adhesive layer depending on the stretching ratio. Thin film coating can be performed more easily than offline coating.

Further, by providing the pressure-sensitive adhesive layer on the film before stretching, the pressure-sensitive adhesive layer can be stretched together with the base film, whereby the pressure-sensitive adhesive layer can be firmly adhered to the base film. Furthermore, in the production of a biaxially stretched polyester film, the film can be constrained in the longitudinal and transverse directions by stretching while gripping the film end portion with a clip or the like, and a flat surface without wrinkles or the like in the heat setting step. High temperature can be applied while maintaining the sex.

Therefore, since the heat treatment applied after coating can be performed at a high temperature that cannot be achieved by other methods, the film-forming property of the adhesive layer is improved, and the adhesive layer and the base film can be more firmly adhered. Furthermore, it can be a strong adhesive layer. Especially, it is very effective for reacting a crosslinking agent.

According to the above in-line coating process, the film size does not change significantly depending on the presence or absence of the adhesive layer, and the risk of scratches or foreign matter does not change significantly depending on the presence or absence of the adhesive layer. This is a great advantage over offline coating which is performed one extra. Furthermore, as a result of various studies, it was found that in-line coating has an advantage that adhesive residue can be reduced, which is a migration of components of the adhesive layer when the film of the present invention is attached to an adherend. It was It is considered that this is because the heat treatment can be performed at a high temperature which cannot be obtained by the off-line coating, and the adhesive layer and the base film are more firmly adhered.

In the present invention, it has an adhesive layer containing a resin having a glass transition point of 0° C. or less and a cross-linking agent, and the adhesive force of the adhesive layer with a polymethylmethacrylate plate is in the range of 1 to 1000 mN/cm. Is an essential requirement.

By setting the adhesive force with the polymethylmethacrylate plate to be in the range of 1 to 1000 mN/cm, it is possible to achieve both the adhesive performance and the peeling performance of peeling after bonding, and various steps of performing the adhesive-peeling operation. It is possible to make the optimum film for use.

As the resin having a glass transition point of 0° C. or lower, a conventionally known resin can be used. Specific examples of the resin include polyester resin, acrylic resin, urethane resin, polyvinyl resin (polyvinyl alcohol, vinyl chloride vinyl acetate copolymer, etc.) and the like. Among them, polyester resin is particularly preferable in consideration of adhesive property and coating property. , Acrylic resins and urethane resins are preferred, polyester resins and acrylic resins are more preferred, and polyester resins are even more preferred, from the viewpoint of strength of adhesive properties. Further, in consideration of the reusability of the film, polyester resin or acrylic resin is preferable, and when the substrate is a polyester film, the polyester resin is also preferable in consideration of adhesion with the substrate, and the change with time is small. Acrylic resin is most preferable in consideration of the lack.

Examples of the polyester resin include those composed of the following polyvalent carboxylic acid and polyvalent hydroxy compound as main constituent components. That is, as the polyvalent carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid and 2,6 -Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodiumsulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutar Acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid, trimellitic acid monopotassium salt and their ester-forming derivatives can be used. As the polyhydric hydroxy compound, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2 -Methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexane dimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene glycol , Polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylethylsulfonate, dimethylolpropion Potassium acid or the like can be used. One or more may be appropriately selected from these compounds, and the polyester resin may be synthesized by a conventional polycondensation reaction.

Among the above, in order to lower the glass transition point to 0° C. or lower, it is preferable to contain an aliphatic polycarboxylic acid or an aliphatic polyhydroxy compound as a constituent component. In general, polyester resins are composed of aromatic polycarboxylic acids and polyhydroxy compounds including aliphatic compounds. Therefore, in order to lower the glass transition point than general polyester resins, it is necessary to use aliphatic polyhydric compounds. It is effective to contain a carboxylic acid. From the viewpoint of lowering the glass transition point, the aliphatic polycarboxylic acid preferably has a long carbon number, and preferably has 6 or more carbon atoms (adipic acid), more preferably 8 or more carbon atoms, and further preferably 10 or more carbon atoms. The upper limit of the preferable range is 20.

From the viewpoint of improving adhesive properties, the content of the aliphatic polycarboxylic acid in the acid component of the polyester resin is preferably 2 mol% or more, more preferably 4 mol% or more, and further preferably 6 mol%. As described above, particularly preferably 10 mol% or more, and the upper limit of the preferable range is 50 mol %.

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

Considering the suitability for in-line coating, it is preferable to use an aqueous system, and therefore, a hydrophilic functional group, sulfonic acid, sulfonic acid metal salt, carboxylic acid, carboxylic acid metal salt, may be contained in the polyester resin. preferable. In particular, sulfonic acid and a metal salt of sulfonic acid are preferable, and a metal salt of sulfonic acid is particularly preferable, from the viewpoint of good dispersibility in water.

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

In addition, considering the appearance of coating in in-line coating, adhesion and blocking to the base film, and reduction of transfer (adhesive residue) to the adherend when used as a surface protection film, the acid component in the polyester resin is considered. As, it is preferable to contain a certain amount of aromatic polycarboxylic acid. Among the aromatic polycarboxylic acids, a benzene ring structure such as terephthalic acid or isophthalic acid is more preferable than a naphthalene ring structure from the viewpoint of adhesive properties. Further, in order to further improve the adhesive property, it is more preferable to use two or more kinds of aromatic polycarboxylic acid in combination.

As the glass transition point of the polyester resin for improving the adhesive property, 0° C. or lower is essential, preferably −10° C. or lower, more preferably −20° C. or lower, and the lower limit of the preferable range is − It is 60°C. By using in the above range, it becomes easy to obtain a film having optimum adhesive properties.

The acrylic resin is a polymer composed of a polymerizable monomer containing an acrylic or methacrylic monomer (hereinafter, acrylic and methacrylic may be collectively referred to as (meth)acrylic). These may be homopolymers or copolymers, and further copolymers with polymerizable monomers other than acrylic and methacrylic monomers.

Also included are copolymers of these polymers with other polymers (eg, polyester, polyurethane, etc.). For example, it is a block copolymer or a graft copolymer. Alternatively, the polymer (polymer mixture in some cases) obtained by polymerizing a polymerizable monomer in a polyester solution or a polyester dispersion is also included. Similarly, a polymer (polymer mixture in some cases) obtained by polymerizing a polymerizable monomer in a polyurethane solution or polyurethane dispersion is also included. Similarly, the polymer (polymer mixture in some cases) obtained by polymerizing the polymerizable monomer in another polymer solution or dispersion is also included.

The polymerizable monomer is not particularly limited, but particularly representative compounds include, for example, various carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Monomers, and salts thereof; such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, monobutylhydroxyfumarate, monobutylhydroxyitaconate Various hydroxyl group-containing monomers; various such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate (Meth)acrylic acid esters; various nitrogen-containing compounds such as (meth)acrylamide, diacetone acrylamide, N-methylol acrylamide or (meth)acrylonitrile; styrene, α-methylstyrene, divinylbenzene, vinyltoluene Various vinyl esters such as various styrene derivatives, vinyl propionate, vinyl acetate; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane and the like; phosphorus-containing vinyl Examples thereof include various monomers, various vinyl halides such as vinyl chloride and vinylidene chloride, and various conjugated dienes such as butadiene.

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

From the viewpoint of adhesive properties, the content of a monomer having a glass transition point of a homopolymer of 0° C. or lower as a monomer constituting an acrylic resin is preferably 30% by weight or more, more preferably 45% by weight as a ratio to the whole acrylic resin. It is in the range of not less than 60% by weight, more preferably not less than 60% by weight, particularly preferably not less than 70% by weight. The upper limit of the preferable range is 99% by weight. Good adhesive properties are likely to be obtained by using in this range.

Further, the glass transition point of a monomer having a homopolymer glass transition point of 0° C. or lower, which improves adhesive properties, is preferably −20° C. or lower, more preferably −30° C. or lower, and further preferably −40° C. or lower. , Particularly preferably -50°C or lower, and the lower limit of the preferable range is -100°C. By using in this range, it becomes easy to obtain a film having suitable adhesive properties.

The monomer used for improving the adhesive property is preferably an alkyl (meth) having an alkyl group having 4 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, and further preferably 4 to 12 carbon atoms. It is an acrylate. Acrylic resins containing normal butyl acrylate and 2-ethylhexyl acrylate, which are industrially mass-produced, are optimal from the viewpoints of handleability and supply stability.

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

The glass transition point of the acrylic resin for improving the adhesive property is essentially 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, and further preferably -30°C. It is in the following range, and the lower limit of the preferable range is −80° C. By using in the above range, it becomes easy to obtain a film having optimum adhesive properties.

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

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

From the viewpoint of improving adhesive properties, the chain-like alkyl chain is a polycarbonate polyol composed of a diol component having a carbon number of preferably 4 to 30, more preferably 4 to 20, and further preferably 6 to 12. , 1,6-hexanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol are industrially mass-produced and have good handling and supply stability. Optimally, the copolymerized polycarbonate polyol contains at least two kinds of diols selected from the above.

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

From the viewpoint of improving the adhesive property, the monomer forming the polyether has an aliphatic diol having a carbon number of preferably 2 to 30, more preferably 3 to 20, and still more preferably 4 to 12, particularly a straight chain fatty acid. It is a polyether polyol containing a group diol.

Polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides. And polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol , 2-methyl-2-propyl-1,3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2 ,5-Dimethyl-2,5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2 -Hexyl-1,3-propanediol, cyclohexanediol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamine, lactone diol, etc.), lactone compounds such as polycaprolactone Examples thereof include those having a derivative unit.

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

Examples of the polyisocyanate compound used to obtain the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α′, α′. An aliphatic diisocyanate having an aromatic ring such as tetramethylxylylene diisocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, aliphatic diisocyanate such as hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Examples thereof include alicyclic diisocyanates such as methane diisocyanate and isopropylidene dicyclohexyl diisocyanate. These may be used alone or in combination of two or more.

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

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

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

In addition, examples of the ionic group to be introduced include various groups such as a carboxyl group, sulfonic acid, phosphoric acid, phosphonic acid, and quaternary ammonium salt, but a carboxyl group is preferable. As a method of introducing a carboxyl group into the urethane resin, various methods can be adopted in each step of the polymerization reaction. For example, there is a method of using a resin having a carboxyl group as a copolymerization component at the time of prepolymer synthesis, and a method of using a component having a carboxyl group as one component such as a polyol, polyisocyanate, or a chain extender. In particular, a method in which a carboxyl group-containing diol is used and a desired amount of a carboxyl group is introduced by the charged amount of this component is preferable.

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

The glass transition point of the urethane resin for improving the adhesive property is essentially 0° C. or lower, preferably −10° C. or lower, more preferably −20° C. or lower, and further preferably −30° C. It is in the following range, and the lower limit of the preferable range is −80° C. By using in the above range, it becomes easy to obtain a film having optimum adhesive properties.

In the present invention, the above-mentioned resins having a glass transition point of 0° C. or lower may be used alone or in combination of two or more. When two or more kinds are used in combination, polyester resin and urethane resin, polyester resin and acrylic resin, urethane resin and acrylic resin may be mentioned, and polyester resin and urethane resin are particularly preferable from the viewpoint of adhesive strength.

In the present invention, an adhesive layer using a resin having a glass transition point of 0° C. or less was mainly studied, but under severe conditions, the adhesive component migrates to the adherend during the study. I understand. As a result of various studies, the inventors have found that the use of a crosslinking agent in combination can improve the migration of the adhesive layer to the adherend, leading to the present invention.

As the cross-linking agent, conventionally known materials can be used, and examples thereof include an epoxy compound, a melamine compound, an oxazoline compound, an isocyanate compound, a carbodiimide compound, a silane coupling compound, a hydrazide compound and an aziridine compound. Among them, an epoxy compound, a melamine compound, an isocyanate compound, an oxazoline compound, a carbodiimide compound, a silane coupling compound is preferable, and further, the adhesive force can be appropriately maintained, and from the viewpoint of easy adjustment, a melamine compound, an isocyanate compound. Compounds, epoxy compounds are more preferable, but melamine compounds and isocyanate compounds are more preferable from the viewpoint that migration to the adherend can be reduced, and from the viewpoint of the strength of the adhesive layer, melamine compounds, adhesion with the base film. From the viewpoint of properties, isocyanate compounds are particularly preferable. These crosslinking agents may be used alone or in combination of two or more.

Depending on the constitution of the pressure-sensitive adhesive layer and the kind of the cross-linking agent, if the content of the cross-linking agent in the pressure-sensitive adhesive layer is too large, the pressure-sensitive adhesive property may be lowered 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 alkylolated melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and these Mixtures can be used. As the alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. The melamine compound may be a monomer, a dimer or higher polymer, or a mixture thereof. Considering the reactivity with various compounds, it is preferable that the melamine compound contains a hydroxyl group. Further, a product obtained by co-condensing a part of melamine with urea or the like can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

The isocyanate-based compound is a compound having an isocyanate derivative structure represented by isocyanate or blocked isocyanate. As the isocyanate, for example, an aromatic isocyanate such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, or an aromatic ring such as α,α,α′,α′-tetramethylxylylene diisocyanate. Aliphatic isocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis(4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate, etc. Examples of the alicyclic isocyanate are Further, polymers and derivatives of these isocyanates such as burettes, isocyanurates, uretdiones, and carbodiimide modified products are also included. These may be used alone or in combination of two or more. 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 a blocked isocyanate state, examples of the blocking agent include bisulfites, phenolic compounds such as phenol, cresol and ethylphenol, propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol and alcohols such as ethanol. Compounds, dimethyl malonate, diethyl malonate, methyl isobutanoyl acetate, methyl acetoacetate, ethyl acetoacetate, active methylene compounds such as acetylacetone, mercaptan compounds such as butyl mercaptan, dodecyl mercaptan, ε-caprolactam, δ-valerolactam, etc. Lactam compounds, diphenylaniline, aniline, amine compounds such as ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, formaldehyde, acetoaldoxime, acetone oxime, methyl ethyl ketone oxime, oxime compounds such as cyclohexanone oxime, These may be used alone or in combination of two or more. Among the above, an isocyanate compound blocked with an active methylene-based compound is preferable from the viewpoint of being particularly effective in reducing the transferability of the adhesive layer to the adherend.

Further, the isocyanate compound in the present invention may be used alone, or may be used as a mixture or a combined product with various polymers. From the viewpoint of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or combination of polyester resin and urethane resin.

The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include a condensate of epichlorohydrin and a hydroxyl group or an amino group such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, and bisphenol A. 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, polytetramethylene glycol diglycidyl ether, monoepoxy compounds, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, glycidyl amine compounds N, N, N', N Examples include'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylamino)cyclohexane and the like.

Among the above, polyether-based epoxy compounds are preferable from the viewpoint of good adhesive properties. As the amount of the epoxy group, a polyepoxy compound having a polyfunctionality of three or more functional groups is preferable to a bifunctional one.

The oxazoline compound is a compound having an oxazoline group in its molecule, and a polymer containing an oxazoline group is particularly preferable, and it can be prepared by addition-polymerizing an oxazoline group-containing monomer alone or with another monomer. The addition-polymerizable oxazoline group-containing monomer includes 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 kind or a mixture of two or more kinds thereof can be used. Among these, 2-isopropenyl-2-oxazoline is industrially easily available and suitable. The other monomer is not limited as long as it is a monomer copolymerizable with the addition-polymerizable oxazoline group-containing monomer, and examples thereof include alkyl (meth)acrylate (wherein the alkyl group is 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, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group Group, cyclohexyl group, etc.), unsaturated amides; vinyl acetate, vinyl propionate, and other vinyl esters; methyl vinyl ether, ethyl vinyl ether, and other vinyl ethers; ethylene, propylene, and other α-olefins; vinyl chloride, vinylidene chloride And halogen-containing α,β-unsaturated monomers such as vinyl fluoride; α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene; and one or more of these. Can be used.

The amount of the oxazoline group in the oxazoline compound is preferably in the range of 0.5 to 10 mmol/g, more preferably 1 to 9 mmol/g, further preferably 3 to 8 mmol/g, and particularly preferably 4 to 6 mmol/g. By using it in the above range, the durability of the coating film is improved and the adhesive property is easily adjusted.

The carbodiimide compound is a compound having one or more carbodiimide or carbodiimide derivative structures in the molecule. A polycarbodiimide-based compound having two or more molecules in the molecule is more preferable because of better strength of the adhesive layer and the like.

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

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

The silane coupling compound is an organosilicon compound having an organic functional group and a hydrolyzing group such as an alkoxy group in one molecule. For example, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4- Epoxy group containing compounds such as epoxycyclohexyl)ethyltrimethoxysilane, vinyl group containing compounds such as vinyltrimethoxysilane, 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 and N-phenyl-3-aminopropyltriethoxysilane, tris(trimethoxysilylpropyl) Isocyanurate, isocyanurate group-containing compounds such as tris(triethoxysilylpropyl) isocyanurate, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiene Examples thereof include mercapto group-containing compounds such as ethoxysilane.

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

In addition, these cross-linking agents are used in a design for reacting them in a drying process or a film-forming process to improve the performance of the adhesive layer. It can be inferred that the resulting adhesive layer contains unreacted products of these crosslinking agents, compounds after the reaction, or a mixture thereof.

Further, in the present invention, a resin having a glass transition point of more than 0° C. is used in combination from the viewpoint of the appearance of the adhesive layer, the adjustment of the adhesive force, the strengthening of the adhesive layer, the adhesiveness with the base film, the blocking resistance and the like. It is also possible. Conventionally known materials can be used as the resin having a glass transition point of higher than 0°C. Among them, polyester resin, acrylic resin, urethane resin and polyvinyl (polyvinyl alcohol, vinyl chloride vinyl acetate copolymer, etc.) are preferable. Considering the appearance of the adhesive layer and the influence on the adhesive force, polyester resin, acrylic resin and urethane The resin selected from the resins is more preferable.

The resin having a glass transition point of higher than 0° C. is used for the appearance of the pressure-sensitive adhesive layer, the adjustment of the pressure-sensitive adhesive force, the strengthening of the pressure-sensitive adhesive layer, the adhesion with the substrate film, the improvement of the blocking resistance, etc. It is necessary to be careful because there is a concern that the adhesive strength will be greatly reduced. Among the above-mentioned more preferably used resins, polyester resin, acrylic resin, and urethane resin, the acrylic resin may significantly reduce the adhesive force as compared with the polyester resin and urethane resin. Therefore, more preferable resin is polyester resin or urethane resin.

As the polyester resin having a glass transition point of higher than 0° C., a polyester resin containing an aromatic compound is preferable. As the aromatic compound, an aromatic polyvalent carboxylic acid is more preferable than an aromatic polyvalent hydroxy compound from the viewpoint of adjusting the adhesive strength and the like. The content of the aromatic polycarboxylic acid as the proportion of the acid component in the polyester resin is preferably 50% by weight or more, more preferably 70% by weight or more, further preferably 80% by weight or more, and particularly preferably It is in the range of 90% by weight, and it is preferable not to contain an aliphatic polycarboxylic acid, particularly an aliphatic polycarboxylic acid having 6 or more carbon atoms, from the viewpoint of adjusting the adhesive strength and blocking resistance.

As the urethane resin as a resin having a glass transition point of higher than 0° C., various urethanes can be used, but among them, urethanes based on polyester polyols are used from the viewpoints of adjusting adhesive strength, slipperiness and blocking resistance. Resins are more preferred. Further, the polyester polyols preferably contain an aromatic compound, and an aromatic polyvalent carboxylic acid is more preferable than an aromatic polyvalent hydroxy compound from the viewpoint of adjusting the adhesive strength and the like. The content of the aromatic polycarboxylic acid in the urethane resin is preferably 5 to 80% by weight, more preferably 15 to 65% by weight, and further preferably 20 to 50% by weight. By using within the range, it becomes easy to adjust the adhesive force and improve the performance of blocking resistance.

The glass transition point of the resin having a glass transition point of higher than 0° C. is preferably 10° C. or higher, more preferably 20° C. or higher, further preferably 30° C. or higher, and the upper limit of the preferable range is 150° C. Within the above range, the adhesive strength can be adjusted without being excessively lowered, and it becomes easy to improve the performance such as slipperiness and blocking resistance.

Further, in the formation of the adhesive layer, particles can be used together for the purpose of improving blocking property, slipperiness, and adjusting adhesive property. However, care must 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, the average particle size of the particles used is preferably 3 times or less, more preferably 1.5 times or less, further preferably 1.0 times or less than the film thickness of the adhesive layer. The range of 0.8 times or less is particularly preferable. In particular, when it is desired to exert 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.

In the present invention, a functional layer may be provided on the surface of the film opposite to the adhesive layer to impart various functions. For example, it is also preferable to provide a release layer in order to reduce blocking of the film by the adhesive layer, and in order to prevent defects such as peeling charge of the film and adhesion of dust around the film due to frictional charging, an antistatic layer is provided. Providing is also a preferable form. The functional layer may be provided by coating, may be provided by in-line coating, or may be off-line coating. In-line coating is preferably used from the viewpoint of manufacturing cost and stabilization of releasing performance and antistatic performance due to in-line heat treatment.

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 a conventionally known release agent can be used. There are, for example, long chain alkyl group-containing compounds, fluorine compounds, silicone compounds, waxes and the like. Of these, long-chain alkyl compounds and fluorine compounds are preferable from the viewpoints of low contamination and excellent blocking reduction, and silicone compounds are preferable when it is particularly important to reduce blocking. In addition, wax is effective for improving the surface contamination removal property. These release agents may be used alone or in combination of two or more.

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 a hexyl group, an octyl group, a decyl group, a lauryl group, an octadecyl group, and a 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. .. A polymer compound is preferable in consideration of heat resistance and stain resistance. Further, from the viewpoint of effectively obtaining releasability, a polymer compound having a long chain alkyl group in its side chain is more preferable.

The polymer compound having a long chain alkyl group in its 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, an acid anhydride and the like.
Examples of the compound having these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, reactive group-containing polyester resin, reactive group-containing poly(meth)acrylic resin, and the like. Of these, polyvinyl alcohol is preferable in view of releasability and ease of handling.

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

Further, the polymer compound having a long-chain alkyl group in the side chain can also be obtained by polymerizing a long-chain alkyl (meth)acrylate or copolymerizing a long-chain alkyl (meth)acrylate with 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. To be

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 fluorine atom-containing olefin compounds, and aromatic fluorine compounds such as fluorobenzene. .. From the viewpoint of releasability, a compound having a perfluoroalkyl group is preferable. Further, as the fluorine compound, a compound containing a long chain alkyl compound as described below can also be used.

The compound having a perfluoroalkyl group is, for example, perfluoroalkyl(meth)acrylate, perfluoroalkylmethyl(meth)acrylate, 2-perfluoroalkylethyl(meth)acrylate, 3-perfluoroalkylpropyl(meth)acrylate. , 3-perfluoroalkyl-1-methylpropyl (meth)acrylate, 3-perfluoroalkyl-2-propenyl (meth)acrylate and other perfluoroalkyl group-containing (meth)acrylates and polymers thereof, perfluoroalkylmethyl vinyl ether , 2-perfluoroalkylethyl vinyl ether, 3-perfluoropropyl vinyl ether, 3-perfluoroalkyl-1-methylpropyl vinyl ether, 3-perfluoroalkyl-2-propenyl vinyl ether, and other perfluoroalkyl group-containing vinyl ethers and polymers thereof. And so on. A polymer is preferable in consideration of heat resistance and stain resistance. The polymer may be a single compound or a polymer of a plurality of 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 below. From the viewpoint of adhesion to the substrate, it is also preferably a polymer with vinyl chloride.

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, and phenyl silicone having a phenyl group, methylphenyl silicone and the like. As the silicone, those having various functional groups can be used, and examples thereof include 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 by using both together, addition type (type by addition reaction of vinyl group and hydrogen silane) silicone It is also possible to use as.

Further, as the silicone compound, it is also possible to use modified silicone such as acrylic graft silicone, silicone graft acrylic, amino modified silicone, perfluoroalkyl modified silicone. In consideration of heat resistance and stain resistance, it is preferable to use a curable silicone resin, and the curable type may be any of a condensation reaction type, an addition type, an active energy ray curable type and the like. Among these, the condensation type silicone compound is preferable from the viewpoint that there is little back surface transfer when it is rolled.

As a preferred form of using a silicone compound, a polyether group-containing silicone compound is preferred from the viewpoints of low backside transfer, good dispersibility in an aqueous solvent, and high suitability for in-line coating. The polyether group may be present on the side chain or terminal of the silicone or on the main chain. From the viewpoint of dispersibility in an aqueous solvent, it is preferable to have a side chain or a terminal.

A conventionally known structure can be used for the polyether group. From the viewpoint of dispersibility of the water-based solvent, an aliphatic polyether group is preferable to an aromatic polyether group, and among the aliphatic polyether groups, an alkyl polyether group is preferable. 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 linear alkyl polyether group 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 view of dispersibility in water, and a polyethylene glycol group is particularly preferable.

The number of ether bonds of the polyether group is usually in the range of 1 to 30, preferably 2 to 20, and more preferably 3 to, from the viewpoint of improving dispersibility in an aqueous solvent and durability of the functional layer. There are 15 ranges. If there are few ether bonds, the dispersibility deteriorates, and conversely, if there are too many ether bonds, the durability and release performance deteriorate.

When the polyether group has a side chain or terminal of silicone, the end of the polyether group is not particularly limited, and 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. Of these, a hydroxyl group, an amino group, a carboxylic acid group, and a sulfonic acid group are preferable in view of dispersibility in water and crosslinkability for improving the strength of the functional layer, and the hydroxyl group is particularly preferable.

The content of the polyether group in the polyether group-containing silicone is preferably in the range of 0.001 to 0.30, more preferably 0.01 to 0.20 in terms of molar ratio, with the siloxane bond of the silicone being 1. %, more preferably 0.03 to 0.15%, particularly preferably 0.05 to 0.12%. By using within this range, the dispersibility in water, the durability of the functional layer and the good releasability can be maintained.

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 large in consideration of durability and release performance of the functional layer. It is required to balance the properties of the both, and the number average molecular weight is preferably in the range of 1,000 to 100,000, more preferably in the range of 3,000 to 30,000, and further preferably in the range of 5,000 to 10,000.

Further, in consideration of aging of the functional layer, release performance, and contamination in various processes, it is preferable that the low-molecular component of silicone (500 or less in number average molecular weight) 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. When a condensation type silicone is used, vinyl groups (vinyl silane) and hydrogen groups (hydrogen silane) bonded to silicon may cause various performance deterioration with time if they remain unreacted in the functional layer. The content of the functional group therein is preferably 0.1 mol% or less, more preferably not contained.

Since it is difficult to apply the polyether group-containing silicone alone, it is preferable to use it by dispersing it 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, an anionic dispersant and a nonionic dispersant are preferable in consideration of dispersibility of the polyether group-containing silicone and compatibility with a polymer other than the polyether group-containing silicone that can be used for forming the functional layer. .. Further, it is also possible to use a fluorine compound as the dispersant.

As the anionic dispersant, sodium dodecylbenzenesulfonate, sodium alkylsulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl allyl ether sulfate, polyoxyalkylene alkenyl alkenyl Sulfonates such as ammonium ammonium sulfate and sulfates, sulfates such as sodium laurate and potassium oleate, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates Examples thereof include phosphate-based salts such as salts. Among these, the sulfonate type is preferable from the viewpoint of good dispersibility.

As the nonionic dispersant, for example, an ether type obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to a compound having a hydroxyl group such as a higher alcohol or an alkylphenol, a polyhydric alcohol such as glycerin or a saccharide, and a fatty acid are ester-bonded. Examples thereof include an ester type, an ester/ether type obtained by adding an alkylene oxide to a fatty acid or a polyhydric alcohol fatty acid ester, and an amide type in which a hydrophobic group and a hydrophilic group have an amide bond. Among these, the ether type is preferable in consideration of solubility and stability in water, and the type added with ethylene oxide is more preferable in consideration of handleability.

It cannot be said unequivocally because it depends on the molecular weight and structure of the polyether group-containing silicone used, and also on the type of dispersant used. The weight ratio is preferably 0.01 to 0.5, more preferably 0.05 to 0.4, and further preferably 0.1 to 0.3.

The wax is a wax selected from natural wax, synthetic wax, and waxes containing them. The natural wax is a vegetable wax, an animal wax, a mineral wax, or a petroleum wax. Examples of vegetable waxes include candelilla wax, carnauba wax, rice wax, wax and jojoba oil. Animal waxes include beeswax, lanolin, whale wax and the like. Examples of mineral waxes include montan wax, ozokerite, and ceresin. Examples of the petroleum wax include paraffin wax, microcrystalline wax, petrolatum and the like. Examples of synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, acid amides, amines, imides, esters and ketones. Examples of synthetic hydrocarbons include Fischer-Tropsch wax (also known as Sazoir wax) and polyethylene wax, and other low molecular weight polymers (specifically, polymers having a number average molecular weight of 500 to 20,000). The following polymers are also included, that is, polypropylene, ethylene/acrylic acid copolymer, polyethylene glycol, polypropylene glycol, a block or graft conjugate of polyethylene glycol and polypropylene glycol, and the like. Examples of the modified wax include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. The derivative here is a compound obtained by any treatment of purification, oxidation, esterification, saponification, or a combination thereof. Hydrogenated waxes include hydrogenated castor oil and hydrogenated castor oil derivatives.

Of the above, synthetic waxes are preferable, polyethylene waxes are more preferable, and oxidized polyethylene waxes are still more preferable, from the viewpoint of stable properties. The number average molecular weight of the synthetic wax is preferably 500 to 30,000, more preferably 1,000 to 15,000, and further preferably 2,000 to 8,000, from the viewpoint of stability of properties such as blocking and handleability.

When an antistatic functional layer is provided on the surface opposite to the adhesive layer of the film, the antistatic agent contained in the functional layer is not particularly limited, and a conventionally known antistatic agent can be used. A polymer type antistatic agent is preferred because it has good heat resistance and wet heat resistance. Examples of the polymer type antistatic agent include compounds having an ammonium group, polyether compounds, compounds having a sulfonic acid group, betaine compounds, conductive polymers and the like.

The compound having an ammonium group is a compound having an ammonium group in the molecule, and examples thereof include ammonium compounds of aliphatic amines, alicyclic amines and aromatic amines. The compound having an ammonium group is preferably a polymer-type compound having an 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 to obtain a high molecular compound having an ammonium group 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 a copolymer of a monomer containing these and another monomer. May be.

Among the compounds having an ammonium group, a compound having a pyrrolidinium ring is also preferable because it has excellent antistatic properties and heat resistance 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, etc. Even if these alkyl groups and phenyl groups are substituted with the groups shown below, Good. The substitutable group is, for example, a hydroxyl group, an amide group, an ester group, an alkoxy group, a phenoxy group, a naphthoxy group, a thioalkoxy, a thiophenoxy group, a cycloalkyl group, a trialkylammonium alkyl group, a cyano group, or a halogen. Further, two substituents attached to the nitrogen atom may be chemically bonded, for _{example, - (CH 2) m -} (m = 2~5 _{integer), - 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.

In the present invention, the polymer having a pyrrolidinium ring is obtained by subjecting a diallylamine derivative to cyclopolymerization using a radical polymerization catalyst. The polymerization is carried out by using a known solvent such as water or a polar solvent such as methanol, ethanol, isopropanol, formamide, dimethylformamide, dioxane or acetonitrile with a polymerization initiator such as hydrogen peroxide, benzoyl peroxide or tertiary butyl peroxide. However, the method is not limited thereto. In the present invention, a compound having a polymerizable carbon-carbon unsaturated bond with the diallylamine derivative may be used as the copolymerization component.

In addition, a polymer having a structure of the following formula (1) is also preferable in terms of excellent antistatic properties and resistance to moist heat. 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 other structures may establish alkylene group or structure of formula 1 having 1 to 20 carbon ^{atoms, R 4, R 5, R} 6 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a phenyl group And a hydrocarbon group having a functional group such as a hydroxyalkyl group, and X ⁻ are various counter ions.

Among the above, the substituent R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms in the formula (1) from the viewpoint of being particularly excellent in antistatic property and stability against moist heat. ³ is preferably an alkyl group having 1 to 6 carbon atoms, and R ⁴ , R ⁵ , and R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and further preferably , R ⁴ , R ⁵ , and R ⁶ are hydrogen atoms, and the other substituents are alkyl groups having 1 to 4 carbon atoms.

Examples of the anion serving as a counter ion of the ammonium group of the above-mentioned compound having an ammonium group include halogen ions, sulfonates, phosphates, nitrates, alkyl sulfonates, carboxylates and the like.

The number average molecular weight of the compound having an ammonium group is 1,000 to 500,000, preferably 2,000 to 350,000, more preferably 5,000 to 200,000. If the molecular weight is less than 1000, the strength of the coating film may be weakened, or the heat stability may be poor.
When the molecular weight is more than 500000, the viscosity of the coating solution becomes high, which may deteriorate the handleability and coatability.

Examples of the polyether compound include polyethylene oxide, polyether ester amide, and acrylic resin having polyethylene glycol as a side chain.

The compound having a sulfonic acid group is a compound containing a sulfonic acid or a sulfonate in the molecule, and for example, a compound having a large amount of sulfonic acid or a sulfonate such as polystyrene sulfonic acid is preferably used. To be

Examples of the conductive polymer include polythiophene-based, polyaniline-based, polypyrrole-based, polyacetylene-based, and the like. Among them, for example, poly(3,4-ethylenedioxythiophene) is used in combination with polystyrenesulfonic acid, such as polythiophene-based. Is preferably used. The conductive polymer is preferable in comparison with the above-mentioned other antistatic agents in that the resistance value becomes low. However, on the other hand, it is necessary to take measures such as reducing the amount used in applications where coloration and cost are a concern.

It is also a preferable mode that the functional layer which can be provided on the surface of the film opposite to the pressure-sensitive adhesive layer contains both the above-mentioned releasing agent and antistatic agent and has an antistatic releasing function.

In order to form the functional layer, various polymers such as polyester resin, acrylic resin, urethane resin and the like, and a crosslinking agent that can be used for forming the adhesive layer are used together in order to improve the coating appearance, transparency, and control of slipperiness. It is also possible. Particularly, from the viewpoint 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, and a carbodiimide compound in combination, and among them, a melamine compound is particularly preferable.

Particles can be used together with the functional layer for the purpose of blocking and improving slipperiness, as long as the gist of the present invention is not impaired. However, when the functional layer has a releasing property, it often has sufficient blocking resistance and slipperiness, and therefore it may be preferable not to use particles in combination from the viewpoint of the appearance of the functional layer.

Furthermore, in the range that does not impair the gist of the present invention, an antifoaming agent, a coatability improving agent, a thickening agent, an organic lubricant, an antistatic agent, an ultraviolet absorber, if necessary, for forming the adhesive layer and the functional layer, It is also possible to use an antioxidant, a foaming agent, a dye, a pigment and the like in combination.

The resin having a glass transition point of 0° C. or lower in the pressure-sensitive adhesive layer constituting the laminated polyester film of the present invention is preferably 10 to 99.5% by weight, more preferably 30 to 98% by weight, and further preferably The range is 45 to 96% by weight, particularly preferably 55 to 94% by weight, and most preferably 70 to 90% by weight. By using in the above range, a sufficient adhesive force can be easily obtained and the adhesive force can be easily adjusted. If the content is too small, the adhesive strength may be reduced, so it may be necessary to take measures such as increasing the thickness of the adhesive layer. However, in order to increase the film thickness, it is necessary to be careful because the productivity may be adversely affected by the degree of the film thickness or the line speed being lowered depending on the case.

As a ratio in the adhesive layer constituting the laminated polyester film in the present invention, the crosslinking agent is preferably 0.5 to 80% by weight, more preferably 1 to 65% by weight, further preferably 3 to 50% by weight, particularly preferably Is in the range of 5-40% by weight, most preferably 8-25% by weight. By using in the above range, the strength of the adhesive layer can be improved, the transfer of the adhesive layer to the adherend can be reduced, and the adhesive force can be easily adjusted. If the content is too small, migration to the adherend increases, and if the content is too large, the adhesive strength may decrease, so it is necessary to devise measures such as increasing the thickness of the adhesive layer. May be. However, in order to increase the film thickness, it is necessary to be careful because the productivity may be adversely affected by the degree of the film thickness or the line speed being lowered depending on the case.

As a proportion in the adhesive layer constituting the laminated polyester film in the present invention, the particles are preferably 70% by weight or less, more preferably 0.1 to 50% by weight, further preferably 0.5 to 30% by weight, particularly preferably Is in the range of 1 to 20% by weight. When used in the above range, sufficient adhesiveness, blocking resistance and slipperiness can be easily obtained.

As a proportion of the adhesive layer constituting the laminated polyester film in the present invention, the resin having a glass transition point of higher than 0° C. is preferably 80% by weight or less, more preferably 50% by weight or less, further preferably 30% by weight or less. It is a range. When used in the above range, good appearance of the pressure-sensitive adhesive layer, adjustment of pressure-sensitive adhesive strength, strengthening of the pressure-sensitive adhesive layer, adhesion to the substrate film, and improvement of blocking resistance can be expected. If the content is too large, the adhesive strength will decrease, so it may be necessary to take measures such as increasing the thickness of the adhesive layer.

In the laminated polyester film of the present invention, when a functional layer having a mold release property is provided on the side opposite to the adhesive layer, the ratio of the mold release agent as a ratio in the functional layer varies depending on the kind of the mold release agent. Therefore, it is not possible to say unconditionally, but it is preferably in the range of 3% by weight or more, more preferably 15% by weight or more, and further preferably 25 to 99% by weight. If it is less than 3% by weight, the blocking reduction may not be sufficient.

When a long-chain alkyl compound or a fluorine compound is used as a release agent, the proportion in the functional layer is preferably 5% by weight or more, more preferably 15 to 99% by weight, further preferably 20 to 95% by weight, and particularly It is preferably in the range of 25 to 90% by weight. When used in the above range, blocking reduction becomes 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. A compound or an isocyanate compound (among them, a blocked isocyanate blocked with an active methylene compound is particularly preferable), and a melamine compound is particularly preferable 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, further preferably 8 to 95% by weight, particularly preferably It is in the range of 10 to 90% by weight. When used in the above range, blocking reduction becomes effective. The proportion 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. Further, as the crosslinking agent, a melamine compound is preferable from the viewpoint of reducing blocking.

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, 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. When used in the above range, blocking is effectively reduced and the functional layer has a good appearance.

When wax is used as the release agent, the proportion 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 in the above range, blocking can be easily reduced. However, when a wax is used for the purpose of decontaminating the surface, the above-mentioned proportion can be reduced, preferably 1% by weight or more, more preferably 2 to 50% by weight, further preferably 3 to 30% by weight. % Range. The proportion of the cross-linking agent is preferably 90% by weight or less, more preferably 10 to 70% by weight, still more preferably 20 to 50% by weight. Further, as the crosslinking agent, a melamine compound is preferable from the viewpoint of reducing blocking.

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 unequivocally determined because an appropriate amount varies depending on the type of antistatic agent. Is preferably 0.5% by weight or more, more preferably 3 to 90% by weight, further preferably 5 to 70% by weight, particularly preferably 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 adhesion of dust and the like in the surroundings may be insufficient.

When an antistatic agent other than the 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, and further preferably 20 to 70% by weight. The range, particularly preferably the range of 25 to 60% by weight. If it is less than 5% by weight, the antistatic effect is not sufficient, and the effect of preventing adhesion of dust and the like in the surroundings may be insufficient.

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, further 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 adhesion of dust and the like in the surroundings may be insufficient.

The components in the adhesive layer or the functional layer can be analyzed by TOF-SIMS, ESCA, fluorescent X-ray, IR, etc., for example.

Regarding the formation of the adhesive layer or the functional layer, the above-mentioned series of compounds is used as a dispersion of a solution or a solvent, and a liquid whose solid content concentration is adjusted to about 0.1 to 80% by weight is coated on the film. It is preferred to produce a laminated polyester film. Particularly when it is provided by in-line coating, an aqueous solution or an aqueous dispersion is more preferable. The coating liquid may contain a small amount of an organic solvent for the purpose of improving dispersibility in water, improving film-forming property, and the like. Further, the organic solvent may be only one kind, or may be appropriately used two or more kinds.

The film thickness of the pressure-sensitive adhesive layer in the present invention cannot be generally stated because it depends on the material used for the pressure-sensitive adhesive layer, but for more suitable adjustment of the pressure-sensitive adhesive property, blocking property, appearance of the pressure-sensitive adhesive layer, or the like. Is 10 μm or less, preferably 1 nm to 4 μm, more preferably 10 nm to 1 μm, further preferably 20 to 500 nm, particularly preferably 30 to 400 nm. A general adhesive layer has a thick film thickness of several tens of μm, but in such a case, for example, when it is used for manufacturing a polarizing plate, the adhesive film is used as a polarizing plate, a retardation plate or a viewing angle widening plate. When the adhesive is stuck to the adherend and cut, the protrusion of the adhesive in the adhesive layer may occur remarkably. However, the protrusion can be minimized by adjusting the film thickness within the above range. This effect becomes better as the thickness of the adhesive layer is smaller. Further, as the film thickness of the pressure-sensitive adhesive layer is smaller, the absolute amount of the pressure-sensitive adhesive layer present on the film may be smaller, which is also effective in reducing the adhesive residue, which is the transfer of the components of the pressure-sensitive adhesive layer to the adherend. Further, by setting the film thickness in the above range, it was also found that it is possible to achieve an appropriate adhesive strength that is not too strong, and for example, for polarizing plate manufacturing processes, both adhesive performance and release performance of peeling after bonding are compatible. When it is used for an application in which it is necessary to achieve the above, the operation of adhesive-peeling can be easily performed, and an optimum film can be obtained. The thinner the film thickness, the more effective the blocking property is, and when the adhesive layer is formed by in-line coating, it is preferable because it is easy to manufacture. On the contrary, when the film thickness is too thin, the adhesive property depends on the constitution of the adhesive layer. Since it may be lost, it is preferable to use it in the above-mentioned suitable range depending on the application.

The film thickness of the functional layer depends on the function to be provided, and therefore cannot be generally stated. For example, the functional layer for imparting mold release performance and antistatic performance is preferably 1 nm to 3 μm, and more preferably The range is 10 nm to 1 μm, more preferably 20 to 500 nm, and particularly preferably 20 to 200 nm. By using the film thickness of the functional layer within the above range, it is easy to improve the blocking characteristics, the antistatic performance, and the good appearance.

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

In the present invention, the drying and curing conditions for forming the adhesive layer on the film are not particularly limited, but in the case of a method by coating, with respect to the drying of the solvent such as water used in the coating liquid, , Preferably 70 to 150° C., more preferably 80 to 130° C., and further preferably 90 to 120° C. As a guide, the drying time is in the range of 3 to 200 seconds, preferably 5 to 120 seconds. In addition, in order to improve the strength of the adhesive layer, a heat treatment step in the range of preferably 180 to 270°C, more preferably 200 to 250°C, and further preferably 210 to 240°C is performed in the film production process. As a guide, the time of the heat treatment step is 3 to 200 seconds, preferably 5 to 120 seconds.

Moreover, you may use heat treatment and irradiation of active energy rays, 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 and plasma treatment in advance.

As the adhesive force of the adhesive layer of the present invention, it is essential that the adhesive force to the polymethylmethacrylate plate measured by the measuring method described later is 1 to 1000 mN/cm, preferably 3 to 800 mN/cm or more. , More preferably 5 to 500 mN/cm, further preferably 7 to 300 mN/cm, and particularly preferably 10 to 100 mN/cm. If the amount is out of the above range, depending on the adherend, there may be no adhesive force, the adhesive force may be too strong to be easily peeled off, or the blocking of the film may be remarkable.

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

In addition, roughening the film surface on the side opposite to the pressure-sensitive adhesive layer of the film of the present invention (the side of the functional layer when there is a functional layer) is also one of the means for improving the blocking property with the pressure-sensitive adhesive layer side. There is a possibility. It cannot be said unequivocally because it depends on the type and adhesive strength of the adhesive layer, but if the purpose is to improve the blocking property by surface roughness regardless of the functional layer, the film surface on the side opposite to the adhesive layer The arithmetic mean roughness (Sa) is preferably in the range of 5 nm or more, more preferably 8 nm or more, further preferably 30 nm or more, and the upper limit is not particularly limited, but is 300 nm from the viewpoint of transparency as the upper limit of the preferred range. Is. When the releasability is good by a method such as providing a release functional layer on the side opposite to the adhesive layer, the releasability becomes dominant, so that the influence of Sa is small and no special attention is required. However, when the releasability is weak, the influence of Sa may be large, which can be an effective means for improving the blocking characteristics.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist. The measuring method and the evaluating method used in the present invention are as follows.

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

(2) Method of measuring average particle diameter (d50: μm) Shimadzu Corporation, centrifugal sedimentation type particle size distribution measuring device SA-CP3 type equivalent spherical distribution measured by using SA-CP3 value (value by weight) of 50% Was defined as the average particle size.

(3) Method for Measuring Arithmetic Average Roughness (Sa) The film surface on the side opposite to the adhesive layer in Examples and Comparative Examples described later (the surface on the functional layer side when there is a functional layer) is Ryoka Co., Ltd. System, non-contact surface/layer cross-section shape measuring system VertScan (registered trademark) R550GML is used, CCD camera: Sony HR-50 1/3', objective lens: 20x, lens barrel: 1X Body, zoom lens: No Relay, wavelength filter: 530 white, measurement mode: Wave, the output was obtained by polynomial correction of the fourth order.

(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. After that, a section prepared by the ultrathin section method was stained with RuO ₄ , and the cross section of the adhesive layer was measured using TEM (H-7650 manufactured by Hitachi High-Technologies Corporation, accelerating voltage 100V).

(5) Glass transition point PerkinElmer Japan Co., Ltd. make, differential scanning calorimeter (DSC) 8500 was used, and it measured at the temperature rising conditions of -100-200 degreeC per minute 10 degreeC.

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

(7-1) Adhesive strength evaluation method (adhesive strength 1)
On the surface of a polymethylmethacrylate plate (Komoray Co., Ltd., Kuraray Co., Ltd., thickness 1 mm), the pressure-sensitive adhesive layer surface of the laminated polyester film of the present invention having a width of 5 cm was crimped back and forth with a 2 kg rubber roller having a width of 5 cm at room temperature. The peeling force after standing for 1 hour was measured. As the peeling force, “Ezgraph” manufactured by Shimadzu Corporation was used, and 180° peeling was performed under the condition of a pulling speed of 300 mm/min.

(7-2) Adhesive strength evaluation method (adhesive strength 2)
(7-1) In place of the polymethylmethacrylate plate of (7-1), the adhesive strength was evaluated by using the polyester film surface (thickness 38 μm) without the adhesive layer obtained in Comparative Example 1 described later (7-1 ) And evaluated.

(8) Method for evaluating reworkability of adhesive layer The adhesive layer side of one A4 size laminated polyester film and the A4 size polyester film without an adhesive layer of Comparative Example 1 to be described later are overlaid and strongly pressed with a finger to provide adhesive properties. Was evaluated. There are 5 points when the film sticks only by lightly pressing it with your finger, and you can keep the stuck state even if you only have the film with the adhesive layer, the film sticks by pressing firmly with your finger, and the adhesive layer There are 4 points where you can keep the stuck state even if you have only the film you have, the film sticks by pressing firmly with your finger, and you can keep the stuck state even if you only have the film that has the adhesive layer You can, but 3 points if it peels off within 3 seconds, a small adhesive property is seen on the film by pressing strongly with your finger, but 2 points if you can not keep the stuck state, strongly pressing with your finger However, the case where no adhesive property was observed at all was given 1 point.
When the same operation was performed again at the same location after peeling off the film, the case where the evaluation results were equivalent was marked with ◯, and the case where the adhesive property was deteriorated was marked with x.

(9) Adhesive layer adhesive residue (transfer characteristic) evaluation method In the above evaluation method (7), the adhesive film was observed after peeling off the adhered film, and there was no adhesive residue (adhesive layer transfer trace). The case where there was adhesive residue was marked as x.

(10) Blocking property measuring method Two polyester films to be measured are prepared, and the adhesive layer side and the side opposite to the adhesive layer (the functional layer side when there is a functional layer) are overlapped, and the area is 12 cm×10 cm. Was pressed under the conditions of 40° C., 80% RH, 10 kg/cm ² , and 20 hours. After that, the films were peeled from each other according to the method specified in ASTM D1893, and the peeling load was measured.
The lighter the peeling load, the better the blocking resistance and the better, 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, most preferably 8 g/cm. The range is as follows. In this evaluation, those exceeding 300 g/cm, those in which the film was broken during the evaluation, and those in which obvious blocking was generated by the press were not practical, and in those cases, they were evaluated as x. ..

(11) Method of 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 polymethylmethacrylate plate (Komoray Co., Ltd. (registered trademark), thickness 1 mm) The layer surface was pressed back and forth twice with a 2 kg rubber roller having a width of 5 cm, attached, treated at 60° C. for 5 days, and then the film was peeled off to observe the surface of the polymethylmethacrylate plate.
○ When there is no mark on the polymethylmethacrylate plate (no migration of the adhesive layer is observed), △ when slightly thin mark is left near the edge of the film, and white mark is observed other than near the edge The case where the adhesive layer was transferred was marked with x. In addition, when it did not stick to the adherend, it was described as "-".

(12) Method of measuring surface resistance Using a high resistance measuring device: HP4339B and measuring electrode: HP16008B manufactured by Hewlett-Packard Japan, a polyester film was sufficiently conditioned under a measuring atmosphere of 23° C. and 50% RH, and then applied. The surface resistance of the antistatic layer was measured after 1 minute at a voltage of 100V.

(13) Method for evaluating dust adhesion on functional layer (antistatic layer) side After sufficiently controlling the humidity of a polyester film in a measurement atmosphere of 23° C. and 50% RH, rub the antistatic layer 10 times with a cotton cloth. This was gently brought close to the finely crushed cigarette ash, and the ash adhesion state was evaluated according to the following criteria.
◯: Does not adhere even when the film is contacted with ash Δ: A little adheres when the film is contacted with ash ×: A large amount adheres only when the film is brought close to ash

The polyesters used in the examples and comparative examples were 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 produced polyester, magnesium acetate tetrahydrate as a catalyst with 100 ppm of the ester at 260° C. in a nitrogen atmosphere at 260° C. The chemical reaction was carried out. Subsequently, 50 ppm of tetrabutyl titanate was added to the produced polyester, the temperature was raised to 280° C. over 2 hours and 30 minutes, the absolute pressure was reduced to 0.3 kPa, and melt polycondensation was continued for 80 minutes to obtain an intrinsic viscosity. A polyester (A) having 0.63 and an amount of diethylene glycol of 2 mol% was obtained.

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

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

<Production method of polyester (D)>
A polyester (D) is produced in the same manner as in the method for producing the polyester (A) except that 0.6 part by weight of silica particles having an average particle size 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.
(Compound example)
・Polyester resin: (IA)
Aqueous dispersion of polyester resin (glass transition point: -20°C) consisting of the following composition Monomer composition: (acid component) dodecanedicarboxylic acid/terephthalic acid/isophthalic acid/5-sodium sulfoisophthalic acid//(diol component) ethylene Glycol/1,4-butanediol=20/38/38/4//40/60 (mol%)
・Polyester resin: (IB)
Aqueous dispersion of polyester resin (glass transition point: -30°C) having the following composition Monomer composition: (acid component) dodecanedicarboxylic acid/terephthalic acid/isophthalic acid/5-sodium sulfoisophthalic acid//(diol component) ethylene Glycol/1,4-butanediol=30/33/33/4//40/60 (mol%)
・Acrylic resin: (IC)
Aqueous dispersion of acrylic resin (glass transition point: −50° C.) having the following composition 2-ethylhexyl acrylate/lauryl methacrylate/2-hydroxyethyl methacrylate/acrylic acid/methacrylic acid=50/25/15/5/5 (weight%)
・Acrylic resin: (ID)
Aqueous dispersion of acrylic resin (glass transition point: −30° C.) having the following composition Normal butyl acrylate/2-ethylhexyl acrylate/ethyl acrylate/2-hydroxyethyl methacrylate/acrylic acid=20/20/56/2/ 2 (wt%)
・Urethane resin: (IE)
Aqueous dispersion of urethane resin (glass transition point: -30° C.) consisting of the following composition: Polycarbonate polyol having a number average molecular weight of 2000 and 1,6-hexanediol and diethyl carbonate/polyethylene glycol having a number average molecular weight of 400/butanediol/ Isophorone diisocyanate/dimethylolpropionic acid=83/2/2/11/2 (wt%)

-Melamine compound: (IIA) Hexamethoxymethylol melamine-Isocyanate compound: (IIB)
1000 parts of hexamethylene diisocyanate was stirred at 60° C., and 0.1 part of tetramethylammonium capryate was added as a catalyst. After 4 hours, 0.2 part of phosphoric acid was added to stop the reaction to obtain an isocyanurate type polyisocyanate composition. 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 the mixture was kept at 80° C. for 7 hours. Thereafter, the reaction solution temperature was maintained at 60° C., 35.8 parts of methyl isobutanoyl acetate, 32.2 parts of diethyl malonate, and 0.88 parts of a 28% methanol solution of sodium methoxide were added and maintained for 4 hours. Blocked 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 parts of 2-ethylhexyl acid phosphate.
・Oxazoline compound: (IIC)
Acrylic polymer Epocros having oxazoline group and polyalkylene oxide chain (oxazoline group amount=4.5 mmol/g, manufactured by Nippon Shokubai Co., Ltd.)
Epoxy compound: (IID) polyfunctional polyepoxy compound, polyglycerol polyglycidyl ether

・Polyester resin: (IIIA)
Aqueous dispersion of polyester resin (glass transition point: 30° C.) having the following composition Monomer composition: (acid component) terephthalic acid/isophthalic acid/5-sodium sulfoisophthalic acid//(diol component) ethylene glycol/1,4 -Butanediol/diethylene glycol=40/56/4//45/25/30 (mol%)
・Polyester resin: (IIIB)
Aqueous 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)
Water dispersion of urethane resin (glass transition point: 50° C.) consisting of the following composition: Isophorone diisocyanate unit/terephthalic acid unit/isophthalic acid unit/ethylene glycol unit/diethylene glycol unit/dimethylolpropanoic acid unit=12/19/18/21 /25/5 (mol%)
・Acrylic resin: (IIID)
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 (wt %)

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

・Release agent (compound containing long-chain alkyl group): (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 started to reflux, 100 parts of polyvinyl alcohol having an average polymerization degree of 500 and a saponification degree of 88 mol% was added little by little at intervals of 10 minutes for about 2 hours. After the addition of polyvinyl alcohol was completed, the mixture was refluxed for another 2 hours to complete the reaction. When the reaction mixture was cooled to about 80° C. and then added to methanol, a reaction product was precipitated as a white precipitate. This precipitate was filtered off, 140 parts of xylene was added, and the mixture was heated to completely dissolve it. After that, the operation of adding methanol again to cause precipitation was repeated several times, and then the precipitate was washed with methanol and dried and pulverized.

・Release agent (fluorine compound): (VB)
Aqueous dispersion of fluorine compound having the following composition Octadecyl acrylate/Perfluorohexyl ethyl methacrylate/Vinyl chloride=66/17/17 (wt%)

-Polyether group-containing condensed silicone: (VC)
Polyether group-containing silicone having a number average molecular weight of 7,000 (silicone siloxane) containing 1 side chain of dimethyl silicone and 1 polyethylene glycol (terminal is a hydroxyl group) having 8 ethylene glycol chains per 100 moles of dimethyl siloxane. When the number of bonds is 1, the ether bond of the polyether group is 0.07 in a molar ratio. 3% of low molecular weight components having a number average molecular weight of 500 or less, no silicon-bonded vinyl group (vinylsilane) and hydrogen group (hydrogensilane). In addition, this compound was obtained by blending sodium dodecylbenzene sulfonate at a ratio of 0.25 with a polyether group-containing silicone as 1 and dispersing in water.

・Wax: (VD)
In an emulsification equipment with an internal capacity of 1.5 L equipped with a stirrer, a thermometer, and a temperature controller, a melting point of 105° C., an acid value of 16 mg KOH/g, a density of 0.93 g/mL, 300 g of a polyethylene oxide wax having a number average molecular weight of 5000, and 650 g of ion-exchanged water. 50 g of decaglycerin monooleate surfactant and 10 g of 48% potassium hydroxide aqueous solution were added, and after replacing with nitrogen, the mixture was sealed, stirred at 150° C. for 1 hour at high speed and cooled to 130° C., and a high-pressure homogenizer under 400 atm. A wax emulsion that was passed and cooled to 40°C.

・Antistatic agent (quaternary ammonium salt compound): (VIA)
Polymer having a pyrrolidinium ring in the main chain and polymerized with the following composition: diallyldimethylammonium chloride/dimethylacrylamide/N-methylolacrylamide=90/5/5 (mol%). Number average molecular weight 30,000.

・Antistatic agent (compound having ammonium group): (VIB)
A polymer compound having a number average molecular weight of 50,000, whose counter ion is a methanesulfonate ion, which is composed of a structural unit represented by the following formula (2).

Example 1:
A mixed raw material obtained by mixing polyesters (A), (B), and (C) at a ratio of 91%, 3%, and 6%, respectively, was used as a raw material for the outermost layer (surface layer), and each of the polyesters (A) and (B) was 97%. %, 3% as a raw material for the intermediate layer, each of which is supplied to two extruders, melted at 285° C., and then melted at 2° C. on a cooling roll set at 40° C. An unstretched sheet was obtained by coextrusion and cooling and solidification in a layer structure of layers (surface layer/intermediate layer/surface layer=discharge amount of 3:32:3).
Then, the film was stretched 3.1 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 one side of the machine direction stretched film to obtain a film thickness of the adhesive layer (dry). The coating solution B1 shown in Table 2 below is applied on the opposite surface so that the thickness of the functional layer (after drying) is 30 nm, and the solution is guided to a tenter at 95°C. After drying for 10 seconds, it was stretched 4.2 times in the transverse direction at 120° C., heat-treated at 230° C. for 10 seconds, and then relaxed by 2% in the transverse direction, the thickness was 38 μm, the back surface side of the adhesive layer (function). A polyester film having a surface (layer side) Sa of 9 nm was obtained.

Evaluation of the completed polyester film revealed that the adhesive strength to the polymethylmethacrylate plate was 10 mN/cm, the adhesive properties were good, the blocking resistance was excellent, and the transfer to the adherend was not observed. .. The properties of this film are shown in Tables 3 and 4 below.

Examples 2-236, 327-334:
A polyester film was obtained in the same manner as in Example 1 except that the coating agent composition shown in Tables 1 and 2 was changed. As shown in Tables 3 to 14, 21 and 22 below, the resulting polyester film had good adhesiveness, blocking resistance and transferability to an adherend.

Examples 237-326:
A polyester film was obtained in the same manner as in Example 1 except that the coating agent composition shown in Tables 1 and 2 was changed. As shown in Tables 15 to 20 below, the finished polyester film had good adhesive strength, blocking resistance, transferability to an adherend, and antistatic performance.

Example 335:
Polyesters (A), (B), and (C) were mixed at a ratio of 91%, 3%, and 6%, respectively, and a mixed raw material was used as a raw material for the outermost layer (surface layer 1), and polyesters (A), (B), ( The mixed raw materials obtained by mixing D) at 72%, 3%, and 25% were used as raw materials for the outermost layer (surface layer 2), and polyesters (A) and (B) were mixed at 97% and 3%, respectively. Using the mixed raw material as the raw material for the intermediate layer, each was supplied to two extruders and melted at 285° C. respectively, and then three types of three layers (surface layer 1/intermediate layer/surface layer) were placed on a cooling roll set to 40° C. A discharge amount of 2=6:26:6) was used to co-extrude and cool and solidify to obtain an unstretched sheet. Then, the film was stretched 3.1 times in the machine direction at a film temperature of 85° C. using the roll peripheral speed difference, and then the coating solution A1 shown in Tables 1 and 2 below was applied to the surface layer 1 side of the film. It is applied so that the film thickness (after drying) will be 120 nm, and the coating solution B1 shown in Table 2 below is applied so that the film thickness (after drying) of the functional layer will be 30 nm, and it will be introduced into a tenter. After drying at 95° C. for 10 seconds, the film was laterally stretched 4.2 times at 120° C., heat-treated at 230° C. for 10 seconds, and then relaxed by 2% in the lateral direction, the thickness was 38 μm, and the adhesive layer A polyester film having a back surface (surface layer 2 side, functional layer side) with Sa of 30 nm was obtained.

Evaluation of the completed polyester film revealed that the adhesive strength to the polymethylmethacrylate plate was 20 mN/cm, the adhesive properties were good, the blocking resistance was excellent, and the transfer to the adherend was not observed. .. The properties of this film are shown in Tables 21 and 22 below.

Examples 336-342:
A polyester film was produced in the same manner as in Example 335 except that the coating composition was changed to the coating composition shown in Tables 1 and 2. As shown in Tables 21 and 22 below, the resulting polyester film had good adhesive strength and transferability to an adherend.

Example 343:
Polyesters (A), (B), and (C) were mixed at a ratio of 91%, 3%, and 6%, respectively, and a mixed raw material was used as a raw material for the outermost layer (surface layer 1), and polyesters (A), (B), ( D) was mixed in the proportions of 47%, 3% and 50%, respectively, and the raw materials for the outermost layer (surface layer 2) were used, and polyesters (A) and (B) were mixed in the proportions of 97% and 3%, respectively. Using the mixed raw material as the raw material for the intermediate layer, each was supplied to two extruders and melted at 285° C. respectively, and then three types of three layers (surface layer 1/intermediate layer/surface layer) were placed on a cooling roll set to 40° C. 2=4:30:4 discharge amount) was coextruded and solidified by cooling to obtain an unstretched sheet. Then, the film was stretched 3.1 times in the machine direction at a film temperature of 85° C. using the roll peripheral speed difference, and then the coating solution A1 shown in Table 1 below was applied to the surface layer 1 side of this longitudinally stretched film. After drying (after drying) to 120 nm, it is introduced into a tenter, dried at 95° C. for 10 seconds, then stretched 4.2 times in the transverse direction at 120° C., and heat treated at 230° C. for 10 seconds. Then, the polyester film was relaxed in the lateral direction by 2% to obtain a polyester film having a thickness of 38 μm and a Sa on the back surface side of the adhesive layer of 55 nm.

The polyester film thus produced was evaluated and found to have an adhesive strength with a polymethylmethacrylate plate of 20 mN/cm, good adhesive properties, excellent blocking resistance and no transfer to an adherend. The properties of this film are shown in Tables 21 and 22 below.

Examples 344-348:
A polyester film was obtained in the same manner as in Example 343, except that the coating composition was changed to the coating composition shown in Table 1 in Example 343. As shown in Tables 21 and 22 below, the resulting polyester film had good adhesiveness, blocking resistance and transferability to an adherend.

Comparative Example 1:
A polyester film was obtained in the same manner as in Example 1 except that the adhesive layer and the functional layer were not provided. When the completed polyester film was evaluated, as shown in Table 23 below, it was a film having no adhesive force.

Comparative Examples 2-9:
A polyester film was obtained in the same manner as in Example 1 except that the coating agent composition shown in Tables 1 and 2 was changed. As shown in Tables 23 and 24, the completed polyester film was found to have no adhesive force and poor transferability to an adherend.

Comparative Example 10:
A polyester film was obtained in the same manner as in Example 1 except that the adhesive layer and the functional layer were not provided. Coating solution C5 shown in Table 1 below was applied onto the polyester film without the adhesive layer so that the film thickness (after drying) of the adhesive layer was 150 nm, followed by drying at 100° C. for 60 seconds, followed by offline coating. A polyester film having an adhesive layer laminated thereon was obtained. As shown in Table 24, the finished polyester film had poor transfer characteristics and transferability to an adherend.

Comparative Example 11:
On a polyester film having no adhesive layer and no functional layer obtained in Comparative Example 1, coating solution C5 shown in Table 1 below was applied at 100° C. for 120 seconds so that the adhesive layer had a thickness (after drying) of 20 μm. It was dried to obtain a polyester film having an adhesive layer formed by off-line coating. When the adhesive layer side was attached to the polyester film and then cut, a protrusion of the components of the adhesive layer, which was not seen in the examples, was seen, which was a result of concern about contamination by the adhesive component. Further, the adhesive strength was more than 1000 mN/cm, and the measurement could not be performed well. The other properties were as shown in Tables 23 and 24.

The film of the present invention is, for example, a resin plate, a metal plate or the like, in transportation, storage or during processing or surface protection film used for preventing stain adhesion during processing, etc. It can be suitably used for applications in which the adhesive strength is excellent, the heat resistance is excellent, the adhesive property is good, and the migration of the adhesive layer to the adherend is small.

Claims (10)

At least one surface of the polyester film has a pressure-sensitive adhesive layer containing a resin having a glass transition point of 0° C. or less and a cross-linking agent, contains a melamine compound as the cross-linking agent, and forms a polymethylmethacrylate plate for the pressure-sensitive adhesive layer. In the range of 1 to 1000 mN/cm, and the film thickness of the adhesive layer is in the range of 1 nm to 440 nm. A polymethylmethacrylate plate of the adhesive layer, which has a pressure-sensitive adhesive layer containing an acrylic resin having a glass transition point of 0° C. or less and a crosslinking agent directly on at least one surface of the polyester film, and which contains a melamine compound as the crosslinking agent. And a film thickness of the pressure-sensitive adhesive layer in the range of 1 nm to 440 nm. The laminated polyester film according to claim 1, wherein the resin having a glass transition point of 0° C. or lower is at least one selected from polyester resins and urethane resins. The laminated polyester film according to claim 3, wherein the polyester resin has an aliphatic polycarboxylic acid or an aliphatic polyhydroxy compound as a constituent component. The laminated polyester film according to claim 3, wherein the polyester resin contains at least one selected from a sulfonic acid, a sulfonic acid metal salt, a carboxylic acid salt, and a carboxylic acid metal salt. The laminated polyester film according to claim 2, wherein the acrylic resin contains, as a constituent component, an alkyl (meth)acrylate in which an alkyl group has 4 to 30 carbon atoms. The laminated polyester film according to claim 3, wherein the urethane resin contains a polycarbonate polyol or a polyether polyol as a polyol component. The laminated polyester film according to claim 1, which has a functional layer containing a release agent or an antistatic agent on the surface of the polyester film opposite to the adhesive layer. The laminated polyester film according to any one of claims 1 to 7, which has a functional layer containing a release agent and an antistatic agent on the surface of the polyester film opposite to the adhesive layer. The laminated polyester film according to any one of claims 1 to 9, wherein the polyester film has an arithmetic mean roughness (Sa) of 5 nm or more on the film surface on the side opposite to the adhesive layer.