JP2022070213A - Easy-adhesive polyester film - Google Patents

Abstract

To provide an easy-adhesive polyester film that is excellent in antistatic property, and has an easy-adhesive layer with excellent adhesion to an ultraviolet (UV) curable-type ink used in printing or the like, in which a transfer of an antistatic agent in the easy-adhesive layer to another article that comes into contact with the easy-adhesive layer and a back surface of the film itself is suppressed.SOLUTION: There is provided an easy-adhesive polyester film characterized in having an easy-adhesive layer on at least one surface of a polyester film, in which the easy-adhesive layer is formed by curing a composition containing an ion-conducting antistatic agent, a polyester-based resin, and a polycarbonate urethane resin, a surface specific resistance value of a surface of the easy-adhesive layer is 1.0×1013 Ω/sq or less, and a surface specific resistance value of a surface of another polyester film that is in contact with the surface of the easy-adhesive layer after contacting the surface of the easy-adhesive layer with the other polyester film and holding the resulting material at 50°C under a pressure of 1 kg/cm2 for 3 days is 1.0×1014 Ω/sq or more.SELECTED DRAWING: None

Description

The present invention relates to a cavity-containing polyester film having excellent mass productivity, concealing property and whiteness, and excellent adhesiveness and antistatic property. More specifically, an antistatic agent is another article. The present invention relates to an easily adhesive polyester film suitable as an information recording material or a printing material having excellent ink adhesion and reducing migration to the back surface.

Biaxially stretched polyester film has excellent properties such as mechanical properties, electrical properties, and dimensional stability, so labels, tags, IC cards, magnetic recording materials, packaging materials, electrical insulation materials, photosensitive materials, and drawing It is used as a base film in many printing fields such as materials and photographic materials.
Especially when it is used for labels, the surface opposite to the easy-adhesive layer is subjected to inorganic vapor deposition to improve concealment, adhesive processing for sticking to containers, etc., and mold release agents such as silicone. It is also used as a release mount (separator) by applying.

However, polyester films have high insulating properties in these applications, and often cause troubles during printing, such as ink loss due to adsorption of dust due to static electricity during running in various processes, and poor sag due to adsorption between films due to triboelectric charging. There is.

Therefore, as one of the methods for imparting easy-adhesive antistatic property to the surface of the polyester film, a method of applying various resins to the surface of the polyester film and providing a coating layer having easy-adhesive performance and antistatic performance is known. There is.

Even in the conventional polyester-based coating films of various ink adhesion types, there are many methods in which a coating layer made of a specific resin is provided on the surface of the base polyester film (see, for example, Patent Document 1). As the constituent resin of the coating layer, for example, a polyester resin, a polyurethane resin, an acrylic or the like may be mixed alone or in combination of two or more, or the resin and a specific cross-linking agent (melamine, isocyanate, etc.) may be used. Examples include mixed ones.

Further, as a means for obtaining antistatic performance, a polyester-based laminated film stretched in the uniaxial direction can also be obtained by mixing a polymer antistatic agent and an additive (see Patent Documents 2 and 3). ..

An antistatic agent with a polar group is used to impart an antistatic function. Among them, it is known that a cationic antistatic agent and an anionic antistatic agent are used as an effect of lowering the surface intrinsic resistance value in the ion-conducting antistatic agent due to its high polarity. However, when an antistatic agent having a high polar group and high hydrophilicity is used, when mixed with the above polyester resin or polyurethane resin, gelation due to ion adsorption (interaction) is caused by the polar species difference (functional group). There is also a problem that it cannot be used as a coating solution.

Further, in such a conventional technique, it is contained in the film surface and its coating layer due to indoor temperature and humidity under high temperature and high humidity, especially in the case of film roll state in summer, storage of cutting sheet, land transportation, sea transportation, etc. In some cases, the components were transferred to the back. This is because backside migration is unlikely to occur under normal temperature and humidity environments, but it is thought that when the amount of moisture in the atmosphere exceeds a certain temperature and humidity range, the coating film components soften and move to the back surface. In addition to degrading the function of the coating layer, this phenomenon causes the vapor deposition loss (pinhole) when the vapor deposition process is performed in the next process, the repelling phenomenon due to poor appearance, and especially when the antistatic agent component is transferred to the back surface. If a release layer is applied, problems such as poor peelability due to poor curing will occur. That is, it is very difficult for the easy-adhesive layer having the adhesion and antistatic function of printing ink or the like to suppress the transferability to the back surface of the polyester film. In order to avoid this, it is effective to reduce the winding roll pressure and control the temperature and humidity during storage, but it cannot be completely avoided, and there is a problem that it leads to deterioration of productivity.

A certain temperature and humidity range, for example, temperature and humidity data inside a container transported by sea in summer is also disclosed by the transportation industry. The inside of the container is sealed, but the temperature rises to about 40 ° C at the maximum. Further, with respect to humidity, the maximum humidity rises to 80% due to the evaporation of water contained in corrugated cardboard or the like used for packaging materials. Therefore, in order to provide an easily adhesive polyester film that does not easily change in quality even in a harsh environment, it is subject to evaluation conditions under an environment of 50 ° C., and further under moist heat resistant conditions at 60 ° C. and 90% humidity. It is desirable to prevent the components in the coating layer from migrating to other articles or the back surface of the film itself in contact with it.

Japanese Unexamined Patent Publication No. 11-105221 Japanese Unexamined Patent Publication No. 2008-296447 Japanese Unexamined Patent Publication No. 2010-208059

The present invention has been made in the background of the problems of the prior art. That is, an object of the present invention is excellent antistatic property on the surface of the easy-adhesive layer, and another film or separator paper, adhesive surface, or easy-adhesive property in which the antistatic agent in the easy-adhesive layer comes into contact with the easy-adhesive layer. Provided is an easy-adhesive polyester film having an easy-adhesive layer that suppresses migration to the back surface (back surface) of the polyester film itself and has excellent adhesion to ultraviolet (UV) curable ink used for printing and the like. To do.

That is, the present invention has the following configuration.
1. 1. The easy-adhesion layer has an easy-adhesion layer on at least one surface of the polyester film, and the composition containing an ion-conducting antistatic agent, a polyester-based resin, and a polycarbonate urethane resin is cured on the easy-adhesion layer to form a surface of the easy-adhesion layer. The surface intrinsic resistance value is 1.0 × 10 ¹³ Ω / sq or less, and the surface of the easy-adhesion layer is brought into contact with another polyester film and held at 50 ° C., 1 kg / cm ² for 3 days under pressure, and then the easy-to-adhere. An easily adhesive polyester film having a surface intrinsic resistance value of 1.0 × 10 ¹⁴ Ω / sq or more on the surface of the other polyester film that was in contact with the surface of the adhesive layer.
2. 2. The surface intrinsic resistance value of the surface of the easy-adhesive layer is 1.0 after the surface of the easy-adhesive layer is brought into contact with another polyester film and held at 60 ° C. at 90% temperature and humidity at 1 kg / cm for ² days under pressure. × 10 ¹³ Ω / sq or less, the easy-adhesive layer after contacting another polyester film with the surface of the easy-adhesive layer and holding it at 60 ° C. and 90% temperature and humidity at 1 kg / cm for 2 days under ² pressure. The easily adhesive polyester film according to the first item above, wherein the surface intrinsic resistance value of the surface of another polyester film that has been in contact with the surface is 1.0 × 10 ¹³ Ω / sq or more.
3. 3. The easily adhesive polyester film according to the first or second item, wherein the solid content of the ion-conducting antistatic agent is 1 to 8% by mass when the total solid content contained in the composition is 100% by mass. ..
4. The easily adhesive polyester film according to any one of the above 1 to 3, which contains 0 to 50% by mass of a cross-linking agent as a solid content when the total solid content contained in the composition is 100% by mass.

The easy-adhesive polyester film of the present invention has excellent antistatic properties, suppresses the transfer of the antistatic agent contained in the easy-adhesive layer to other articles or the back surface even under high temperature and high humidity, and is used as a UV curable ink. Has excellent adhesiveness.

(Polyester film base material)
In the present invention, the polyester resin constituting the polyester film base material includes polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polytrimethylene terephthalate and the like, as well as the diol component or dicarboxylic acid component of the polyester resin as described above. It is a copolymerized polyester resin in which a part of the above is replaced with the following copolymerization component. For example, as the copolymerization component, a diol component such as diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, polyalkylene glycol, etc. , Adipic acid, sebatic acid, phthalic acid, isophthalic acid, 5-sodium isophthalic acid, dicarboxylic acid components such as 2,6-naphthalenedicarboxylic acid and the like can be mentioned.

The polyester resin suitably used for the polyester film substrate in the present invention is mainly selected from polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. Among these polyester resins, polyethylene terephthalate is most preferable from the viewpoint of the balance between physical properties and cost. Further, the polyester film base material composed of these polyester resins is preferably a biaxially stretched polyester film, and can improve chemical resistance, heat resistance, mechanical strength and the like.

The catalyst for polycondensation used in the production of the polyester resin is not particularly limited, but antimony trioxide is suitable because it is an inexpensive catalyst and has excellent catalytic activity. It is also preferable to use a germanium compound or a titanium compound. Further preferable polycondensation catalysts include catalysts containing aluminum and / or its compounds and phenolic compounds, catalysts containing aluminum and / or its compounds and phosphorus compounds, and catalysts containing aluminum salts of phosphorus compounds.

Polyethylene-based resins, polypropylene-based resins, polyester-based resins, and the like are used as the main raw materials for producing synthetic paper. In particular, polyester-based resins typified by polyethylene terephthalate have excellent mechanical properties. , Due to its thermal properties, it is widely used.

As a method for obtaining a film having a function similar to that of paper, generally, a method of containing a large amount of fine cavities inside the film, or a surface treatment such as sandblasting, chemical etching, or matting treatment on a flat film. There is a method of roughening the surface by performing the above. Among these, the former method of containing a large amount of fine cavities inside the film not only provides paper-like concealment and whiteness, but also makes the film itself lighter, so that the cost per area is reduced. It is widely used because it can be suppressed, and because it has appropriate flexibility and cushioning properties, it has excellent image sharpness during printing.

As a method for expressing fine cavities inside a film, generally, an incompatible thermoplastic resin (hereinafter referred to as an incompatible resin) is mixed with a polyester resin, and the incompatible resin is mixed with the incompatible resin. Examples thereof include a method in which a sheet in which a resin is dispersed is obtained and stretched in at least one axial direction to develop cavities by peeling off the interface between the polyester resin and the incompatible resin. As the incompatible resin for developing cavities with respect to the polyester resin, a polyethylene resin, a polypropylene resin, a polyolefin resin such as a polymethylpentene resin, and a polystyrene resin are preferably used.

The polyester film base material in the present invention is particularly preferably a biaxially oriented polyester film from the viewpoint of practicality such as strength, waist, and dimensional stability.

The layer structure of the polyester film base material may be a single layer structure or a laminated structure, but it is a laminated structure of A layer / B layer / A layer, and the A layer contains inorganic particles and the B layer contains fine cavities. It is a preferable form to have a laminated structure. By arranging a layer containing inorganic particles in the A layer, which is a surface layer, it is possible to improve the slipperiness, that is, the handling property and the hiding property of the film, and the fine cavities are contained only in the inner layer B layer. This makes it possible to obtain a preferable white appearance and to secure the strength of the film surface while exhibiting the cushioning property of the film. Here, the method for forming the laminated structure is not particularly limited, but it is preferable to perform it by coextrusion from the viewpoint of stability during manufacturing and processing cost.

Further, the polyester film base material in the present invention may have a single-layer structure or a multi-layer structure, but it is preferable that some or all of the layers are opaque. The optical density indicating the opacity of the white cavity-containing polyester film is preferably 0.3 or more, more preferably 0.3 to 4.0, and particularly preferably 0.5 to 3.0. .. When the optical density is 0.3 or more, the printing effect becomes clear when printing is performed on the surface of the easy-adhesion layer of the polyester film containing white cavities, which is preferable. Further, when the optical density is 4.0 or less, a better printing effect can be expected, which is preferable.

The method for obtaining the optical density within the above range is not particularly limited, but it can be achieved by containing inorganic particles or a thermoplastic resin incompatible with the polyester resin in the polyester resin. The content thereof is not particularly limited, but in the case of inorganic particles, it is preferably 5 to 35% by mass, and particularly preferably 8 to 25% by mass with respect to the produced polyester. On the other hand, when the incompatible thermoplastic resin is contained, it is preferably 5 to 35% by mass, particularly preferably 8 to 28% by mass with respect to the polyester. Further, when the inorganic particles and the thermoplastic resin incompatible with the polyester resin are used in combination, the total amount thereof should be 40% by mass or less with respect to the polyester film base material. It is preferable from the viewpoint of film stability.

The inorganic particles used are not particularly limited, but inorganic particles having an average particle size of 0.1 to 4.0 μm are preferable, and inorganic particles having an average particle size of 0.3 to 1.5 μm are particularly preferable. Specifically, white pigments such as titanium oxide, barium sulfate, calcium carbonate, and zinc sulfide are preferable, and these may be mixed. In addition, inorganic particles commonly contained in the film, such as silica, alumina, talc, kaolin, clay, calcium phosphate, mica, hectorite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride, calcium sulfate, etc. It may be used together.

Further, the easily adhesive polyester film of the present invention is preferably an easily adhesive fine cavity-containing polyester film having an apparent density of 0.3 to 1.3 g / cm ³ .

Further, the cavity stacking number density is 0.20 pieces / μm or more, preferably 0.25 pieces / μm or more, and more preferably 0.30 pieces / μm or more in terms of both cushioning property and surface peeling strength. A polyester film containing an easily adhesive white cavity is also preferable. As a result, the easily adhesive white cavity-containing polyester film obtained is excellent in print sharpness and processing characteristics at the time of printing. Here, the density of the number of laminated cavities (pieces / μm) is defined by the formula: the number of cavities (pieces) in the film thickness direction / film thickness (μm). The upper limit of the cavity stacking number density is preferably 0.80 pieces / μm, more preferably 0.55 pieces / μm from the viewpoint of cavity development efficiency. As a method of adjusting the same density within the above range, in addition to adjusting the addition amount, type, viscosity, etc. of the incompatible thermoplastic resin, changing the screw shape of the extruder, and static mixer to the molten resin flow path. A method such as installation is used, but this is not the case.

In these easily adhesive white cavity-containing polyester films, the opacity is further improved by causing light scattering at the interface between the fine cavities contained in the film and the polyester which is a matrix, and the addition of the inorganic particles can be reduced. It is especially useful because it can be done. Further, by including the fine cavities, the weight of the base film itself can be reduced, which facilitates handling and has great economic effects such as reduction of raw material cost and transportation cost.

As a method for obtaining such an easily adhesive white cavity-containing polyester film, a thermoplastic resin that is incompatible with the polyester resin as described above is kneaded with the thermoplastic polyester resin that is a matrix, and the thermoplastic resin is mixed. It is possible to use a known method already disclosed, such as a method of forming a cavity around the incompatible resin fine particles by stretching a sheet in which the incompatible resin is dispersed in the form of fine particles at least in the uniaxial direction. can.

Further, the thickness of the obtained polyester film containing an easily adhesive white cavity is preferably 5 to 300 μm. In particular, the thickness of the white laminated polyester film having a cavity laminated number density of 0.20 pieces / μm or more is preferably 20 to 300 μm, more preferably 40 to 250 μm.

The required whiteness when used as a printing material or the like can be expressed by a color value. In particular, the color L value is a measure of lightness, and the higher the value, the whiter the color. Furthermore, when the color b value is high, the yellowish color is strong, and when the value is low, the bluish color is strong. That is, when the L value is high and the b value is low, the whiteness is high, and the visual whiteness is strong. The sharpness at the time of printing will be improved.

(Easy adhesive layer)
The easy-adhesive polyester film of the present invention has an ion-conducting antistatic agent, a polycarbonate urethane resin, and a polyester resin on at least one side thereof in order to improve the back transfer property of the antistatic agent and the adhesion to UV ink. It is preferable that an easy-adhesive layer formed by curing the contained composition is laminated. It is considered that the easy-adhesion layer is formed by curing a cationic antistatic agent or an anionic antistatic agent, a polycarbonate urethane resin or a polyester resin, and expresses the chemical structure itself after the curing. Therefore, it is expressed that the composition containing the cationic or anionic antistatic agent, the polycarbonate urethane resin, and the polyester resin is cured and formed. The easy-adhesive layer may be provided on both sides of the polyester film base material, or may be provided on only one side of the polyester film base material, and a different type of resin coating layer may be provided on the other side.

In the present invention, it is preferable that the easy-adhesive polyester film has antistatic properties such that the surface intrinsic resistance value of the surface of the easy-adhesive layer is 1.0 × 10 ¹³ Ω / sq or less. When the surface intrinsic resistance value of the surface of the easy-adhesion layer is 1.0 × 10 ¹³ Ω / sq or less, there is no adsorption of dust due to friction and static electricity generated at the time of peeling, and the print quality is good, so that the laser beam printer method can be used. It is preferable because there is no scattering of toner particles. Further, when the films are charged and adsorbed to each other, it is possible to prevent phenomena such as poor sabaki and double feed during transport and feed, which is preferable. The surface intrinsic resistance value of the surface of the easy-adhesion layer is more preferably 5.0 × 10 ¹² Ω / sq or less, and further preferably 1.0 × 10 ¹² Ω / sq or less. On the other hand, when the surface specific resistance value is 1.0 × ¹⁰⁸ Ω / sq or more, the polarity does not become too high and the adhesiveness with various inks is good, which is preferable. It is more preferably 5.0 × 10 ⁸ Ω / sq or more, and particularly preferably 1.0 × 10 ⁹ Ω / sq or more.

In the present invention, another polyester film is brought into contact with the surface of the easy-adhesive layer of the easy-adhesive polyester film and held at 50 ° C. and 1 kg / cm ² for 3 days under pressure, and then the surface intrinsic resistance value of the surface of the easy-adhesive layer is obtained. Is preferably 1.0 × 10 ¹³ Ω / sq or less. By having the above-mentioned characteristics, for example, it is difficult for the antistatic agent present in the easy-adhesive layer of the easily-adhesive polyester film wound into a roll to move (set-off) to the opposite surface in contact with the antistatic agent. This means that the antistatic property of the easy-adhesion layer is easily maintained. When the surface intrinsic resistance value of the surface of the easy-adhesion layer after the contact treatment under the above-mentioned specific conditions is 1.0 × 10 ¹³ Ω / sq or less, durable antistatic properties can be obtained, which is preferable. The surface intrinsic resistance value of the surface of the easy-adhesion layer after the contact treatment under the above-mentioned specific conditions is more preferably 5.0 × 10 ¹² Ω / sq or less, and further preferably 1.0 × 10 ¹² Ω / sq. It is less than or equal to sq. On the other hand, when the surface intrinsic resistance value after the contact treatment under the above-mentioned specific conditions is 1.0 × ¹⁰⁸ Ω / sq or more, the polarity does not become too high and the adhesiveness with various inks is good, which is preferable. .. It is more preferably 5.0 × 10 ⁸ Ω / sq or more, and particularly preferably 1.0 × 10 ⁹ Ω / sq or more.

In the present invention, the surface of the easy-adhesive layer is brought into contact with another polyester film and held at 50 ° C. and 1 kg / cm ² for 3 days under pressure, and then the other polyester that has been in contact with the surface of the easy-adhesive layer. It is preferable that the surface intrinsic resistance value of the surface of the film is 1.0 × 10 ¹⁴ Ω / sq or more. By having the above-mentioned characteristics, for example, it is difficult for the antistatic agent present in the easy-adhesive layer of the easily-adhesive polyester film rolled up in a roll shape to move (set off) to the opposite surface in contact with the adhesive layer. Easy-adhesiveness This means that the antistatic property of the easy-adhesive layer of the polyester film is easily maintained. The surface intrinsic resistance value of the surface of the other polyester film after the contact treatment under the above-mentioned specific conditions is more preferably 1.0 × 10 ¹⁴ Ω / sq or more, and more preferably 5.0 × 10 ¹⁴ Ω. It is more preferably / sq or more.

In the present invention, the surface of the easy-adhesive layer after the surface of the easy-adhesive layer of the easy-adhesive polyester film is brought into contact with another polyester film and held at 1 kg / cm ² at 60 ° C. and 90% temperature and humidity for 3 days under pressure. The surface intrinsic resistance value of is preferably 1.0 × 10 ¹³ Ω / sq or less. In the above-mentioned moist heat environment, the antistatic agent in the easy-adhesion layer is considered to be easily transferred to the other surface. The fact that it is 1.0 × 10 ¹³ Ω / sq or less means that, for example, even if the easily adhesive polyester film rolled up in a roll shape is left in a moist heat environment, the antistatic agent present in the easy adhesive layer comes into contact with it. It means that it is difficult to transfer (set-off) to the opposite surface, and the antistatic property of the easily adhesive polyester film is easily maintained. The surface intrinsic resistance value of the surface of the easy-adhesion layer after the contact treatment in the moist heat environment is more preferably 1.0 × 10 ¹³ Ω / sq or less, and more preferably 9.0 × 10 ¹² Ω / sq or less. Is even more preferable. On the other hand, when the surface intrinsic resistance value after the contact treatment under the above-mentioned moist heat conditions is 1.0 × ¹⁰⁸ Ω / sq or more, the polarity does not become too high and the adhesiveness with various inks is good, which is preferable. .. More preferably, it is 5.0 × ¹⁰⁸ Ω / sq or more.

In the present invention, the easy-adhesive layer is obtained after the surface of the easy-adhesive layer of the easy-adhesive polyester film is brought into contact with another polyester film and held at 1 kg / cm ² at 60 ° C. and 90% temperature and humidity for 2 days under pressure. It is preferable that the surface intrinsic resistance value of the surface of the other polyester film that has been in contact with the surface is 1.0 × 10 ¹³ Ω / sq or more. In the above-mentioned moist heat environment, the antistatic agent in the easy-adhesion layer is considered to be easily transferred to the other surface. The surface intrinsic resistance value of the surface of the polyester film is 1.0 × 10 ¹³ Ω / sq or more, for example, even if the easily adhesive polyester film rolled up in a roll shape is left in a moist heat environment. This means that the antistatic agent present in the easy-adhesive layer does not easily move (set off) to the opposite surface in contact with the antistatic agent, and the antistatic property of the easy-adhesive polyester film is easily maintained. More preferably, the surface of the easy-adhesive layer is obtained by bringing another polyester film into contact with the surface of the easy-adhesive layer of the easy-adhesive polyester film and holding the surface of the easy-adhesive layer under 1 kg / cm ² pressure at 60 ° C. and 90% temperature and humidity for 3 days. The surface intrinsic resistance value of the surface of the other polyester film that was in contact with the above is 1.0 × 10 ¹³ Ω / sq or more.

In the present invention, in evaluating the migration of the antistatic agent, it is easy to bring another polyester film into contact with the easy-adhesive layer of the easy-adhesive polyester film of the present invention on both surfaces of the polyester film of the present invention. It is assumed that the polyester film has an adhesive layer, and in that case, it is difficult to make an accurate evaluation when the easily adhesive polyester films of the present invention are overlapped with each other. I am using something that I do not have.

Hereinafter, the constituent components of the easy-adhesive layer will be described in detail.
(Ion conduction type antistatic agent)
As an antistatic agent, those that can suppress the transferability to the back surface of other articles or the film itself that have come into contact with it are preferable. For example, the functional group is a nonionic type such as sorbitan type, ether type, ester type, sorbitol type, glucose type, a quaternary ammonium salt type, a quaternary ammonium resin type, an imidazoline type, an arcobel type, a cationic type such as solomin A type. , Alkyl sulfate type, Alkyl phosphate type, Phosphoric acid ester salt type, Sulfate ester salt type and other anionic and betaine type, Amino acid type, Amino sulfate ester type and other amphoteric surfactant type or polymer type. ..

In the above antistatic agent, the counter ion of the quaternary ammonium base is not particularly limited as long as it is an anionic compound, but is preferably a halogen ion, a mono or polyhalogenated alkyl ion, a nitrate ion, or a sulfate ion. , Alkyl sulfate ion, sulfonate ion or alkyl sulfonate ion, but preferably the stability of the surface intrinsic resistance value, the liquid coating stability, the ink adhesion, and the transferability of the antistatic agent to other articles and the back surface. Etosulfate salt is preferable to suppress the above.

Further, polyethyleneimine, polydimethyldiallyl ammonium salt, polyalkylene polyamine dicyanodiamidammonium condensate, polyvinylpyridium halide, (meth) alkyl acrylate quaternary ammonium salt, (meth) acrylamide alkyl quaternary ammonium salt, ω-chloro-poly. (Oxyethylene-polymethylene-alkyl quaternary ammonium salt), polyvinylbenzyltrimethylammonium salt, polystyrene-based cationic polymer, poly (meth) acrylic-based cationic polymer (methylmethacrylate, ethylacrylate, 2-hydroxyethylmethacrylate, trimethylaminochloride) Ethyl methacrylate, etc.), Polyvinylpyridine-based polymer, cyclic integral type polymer, linear integral type polymer, polymer of aromatic vinyl monomer having two or more quaternary ammonium ion groups in pendant type, pyrrolidium in main chain Examples include a polymer having a ring. These polymers may be homopolymers or copolymers. Known copolymerizable monomers may be used to produce these polymers. In controlling the mixing property of the coating liquid and the abundance of the antistatic agent component on the surface of the easy-adhesion layer, it is preferable that the antistatic agent has a linear alkyl group, and further, it has a linear alkyl group and 4 It is preferably an antistatic agent having a quaternary ammonium base.

Therefore, in an antistatic agent having a linear alkyl group and a quaternary ammonium base, the number of carbon atoms in the alkyl chain is preferably 10 to 25, more preferably 12 to 19. It is particularly preferable that the number is 14 to 18. Considering the interaction between the same molecules and the suppression of back migration due to the molecular length, the above range is preferable.

The molecular weight of the quaternary ammonium base having a linear alkyl group is preferably 200 or more, preferably 700 or less. More preferably, it is 400 or more and 600 or less. When the molecular weight is 200 or less, the surface intrinsic resistance value is likely to be developed, but the back migration cannot be suppressed. When the molecular weight is 700 or more, the surface intrinsic resistance value is less likely to be developed, and aggregation due to interaction with the resin functional group is likely to occur during the preparation of the coating liquid.

Further, in the molecular structure of the cationic antistatic agent having a nitrogen element, at least one amide bond or urethane bond may be contained between the linear alkyl chain and the quaternary ammonium base.

(Polycarbonate urethane resin)
The urethane resin having a polycarbonate structure in the present invention preferably has a urethane bond partial structure derived from at least a polycarbonate polyol component and a polyisocyanate component, and further contains a chain extender, if necessary. Further, a polyisocyanate having a branched structure is synthesized and polymerized by the presence of three or more terminal functional groups of any of the raw material components constituting the molecular chain to form a molecular chain structure on a branch. It is preferably introduced by the above.

The lower limit of the number of terminal functional groups in the molecular chain of the polycarbonate urethane resin in the present invention and the urethane resin having a branched structure is preferably 3 and more preferably 4 depending on the branched structure. When the number is 3 or more, the blocking resistance at the time of water adhesion can be improved, which is preferable. Due to the branched structure of the urethane resin having a polycarbonate structure in the present invention, the upper limit of the number of terminal functional groups in the molecular chain is preferably six. When the number is 6 or less, the resin can be stably dispersed in the aqueous solution, which is preferable.

The polycarbonate polyol component used for synthesizing and polymerizing the polycarbonate urethane resin in the present invention preferably contains an aliphatic polycarbonate polyol having excellent heat resistance and hydrolysis resistance. Examples of the aliphatic polycarbonate polyol include an aliphatic polycarbonate diol and an aliphatic polycarbonate triol, and an aliphatic polycarbonate diol can be preferably used. Examples of the aliphatic polycarbonate diol used for synthesizing and polymerizing the urethane resin having a polycarbonate structure in the present invention include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5. -Pentane diol, 3-methyl-1,5-pentane diol, 1,6-hexane diol, 1,9-nonan diol, 1,8-nonan diol, neopentyl glycol, diethylene glycol, dipropylene glycol and other diols. Examples thereof include aliphatic polycarbonate diols obtained by reacting one or more of them with carbonates such as dimethyl carbonate, ethylene carbonate and phosgene.

The number average molecular weight of the polycarbonate polyol in the present invention is preferably 1000 to 3000. It is more preferably 1200 to 2900, and most preferably 1500 to 2800. When it is 1000 or more, the ink adhesion can be improved, which is preferable. When it is 3000 or less, the back transfer property of the antistatic agent can be suppressed, which is preferable.

Examples of the polyisocyanate used for the synthesis and polymerization of the polycarbonate urethane resin in the present invention include aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and 1,3-bis (isocyanate methyl). ) Alicyclic diisocyanates such as cyclohexane, hexamethylene diisocyanates, and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanates, or a single or a plurality of these compounds are preliminarily added to trimethylene propane or the like. Examples include polyisocyanates. When the above-mentioned aromatic aliphatic diisocyanates, alicyclic diisocyanates, or aliphatic diisocyanates are used, there is no problem of yellowing and it is preferable. Further, it is preferable because the coating film does not become too hard and it is good for obtaining the surface intrinsic resistance value by the antistatic agent.

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

In order to form a branched structure in the urethane resin, for example, the above-mentioned polycarbonate polyol component, polyisocyanate, and chain extender are reacted at an appropriate temperature and time, and then a trifunctional or higher functional hydroxyl group or isocyanate group is formed. A method of adding the compound to be contained and further advancing the reaction can be preferably adopted.

Specific examples of compounds having trifunctional or higher hydroxyl groups include caprolactone triol, glycerol, trimethylolpropane, butanetriol, hexanetriol, 1,2,3-hexanetriol, 1,2,3-pentanthriol, 1,3. , 4-Hexanetriol, 1,3,4-pentantriol, 1,3,5-hexanetriol, 1,3,5-pentantriol, polyethertriol and the like. Examples of the polyether triol include ethylene oxide, propylene oxide, and butylene, starting with one or more compounds having three active hydrogens, such as alcohols such as glycerin and trimethylolpropane, and diethylenetriamine. Examples thereof include compounds obtained by addition-polymerizing one or more of monomers such as oxide, amylen oxide, glycidyl ether, methyl glycidyl ether, t-butyl glycidyl ether, and phenyl glycidyl ether.

Specific examples of the compound having a trifunctional or higher functional isocyanate group may be a polyisocyanate compound having at least three or more isocyanate (NCO) groups in one molecule. In the present invention, the trifunctional or higher functional isocyanate compound has two isocyanate groups, such as an aromatic diisocyanate, an aliphatic diisocyanate, an aromatic aliphatic diisocyanate, and an alicyclic diisocyanate, which are modified with an isocyanate monomer. Adduct body and the like can be mentioned.
The aromatic diisocyanate is, for example, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylenedi isocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate. Examples thereof include isocyanates, 4,4'-toluene diisocyanates, dianisidine diisocyanates, and 4,4'-diphenyl ether diisocyanates.
Aliphatic diisocyanates include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylenedi isocyanate, 1,3-butylenedi isocyanate, dodecamethylene diisocyanate, and 2, Examples thereof include 4,4-trimethylhexamethylene diisocyanate.
Examples of the aromatic aliphatic diisocyanate include xylylene diisocyanate, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate.
The alicyclic diisocyanate is, for example, 3-isocyanate methyl-3,5,5-trimethylcyclohexylisocyanate (also known as IPDI, isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexane. Examples thereof include diisocyanate, methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), and 1,4-bis (isocyanatemethyl) cyclohexane.
The burette body is a self-condensate having a burette bond formed by self-condensation of an isocyanate monomer, and examples thereof include a burette body of hexamethylene diisocyanate.
The nurate form is a trimer of an isocyanate monomer, and examples thereof include a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate, and a trimer of tolylene diisocyanate.
The adduct is a trifunctional or higher functional isocyanate compound obtained by reacting the above isocyanate monomer with a trifunctional or higher low molecular weight active hydrogen-containing compound, for example, a compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate. , A compound obtained by reacting trimethylolpropane and tolylene diisocyanate, a compound obtained by reacting trimethylolpropane and xylylene diisocyanate, a compound obtained by reacting trimethylolpropane and isophorone diisocyanate, and the like.

Examples of the chain extender having a trifunctional or higher functional number include trimethylolpropane in the description of the chain extender and alcohols having a trifunctional or higher hydroxyl group such as pentaerythritol.

The easy-adhesive layer in the present invention is preferably provided by an in-line coating method described later using a water-based coating liquid. Therefore, it is desirable that the urethane resin of the present invention has water solubility or water dispersibility. The above-mentioned "water-soluble or water-dispersible" means that water or a water-soluble organic solvent is dispersed in an aqueous solution containing less than 50% by mass.

In order to impart water dispersibility to the urethane resin, a sulfonic acid (salt) group or a carboxylic acid (salt) group can be introduced (copolymerized) into the urethane molecular skeleton. In order to maintain moisture resistance, it is preferable to introduce a weakly acidic carboxylic acid (salt) group, and it is preferable because the interaction (gelation) with the cationic antistatic agent can be suppressed. Further, a nonionic group such as a polyoxyalkylene group can be introduced.

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

When a polyol compound having a carboxylic acid (salt) group is used as a copolymerization component in order to impart water dispersibility, the composition molar ratio of the polyol compound having a carboxylic acid (salt) group in the urethane resin is the urethane resin. When the total polyisocyanate component of the above is 100 mol%, it is preferably 3 to 60 mol%, and preferably 5 to 40 mol%. When the composition molar ratio is 3 mol% or more, water dispersibility can be obtained, which is preferable. Further, when the composition molar ratio is 60 mol% or less, water resistance is maintained and moisture heat resistance is obtained, which is preferable.

The urethane resin in the present invention may have a blocked isocyanate structure at the end in order to improve the hardness.

(Crosslinking agent)
In the present invention, blocked isocyanate may be added as a cross-linking agent to the composition for forming an easy-adhesion layer. A trifunctional or higher functional block isocyanate is more preferred, and a tetrafunctional or higher functional blocked isocyanate is particularly preferred. These make it possible to control the antistatic property of the surface of the easy-adhesive layer and suppress the back transfer property of the antistatic agent.

The blocked isocyanate in the present invention can introduce a hydrophilic group into the precursor polyisocyanate in order to impart water solubility or water dispersibility. Examples of the hydrophilic group include (1) a quaternary ammonium salt of a dialkylaminoalcohol and a quaternary ammonium salt of a dialkylaminoalkylamine, (2) a sulfonate, a carboxylate, a phosphate and the like, and (3) an alkyl group. Examples thereof include polyethylene glycol and polypropylene glycol that are sealed at one end. When a hydrophilic site is introduced, it becomes (1) cationic, (2) anionic, and (3) nonionic. Among them, since many other water-soluble resins are anionic, anionic and nonionic resins that can be easily compatible with each other are preferable. Further, since the anionic property has excellent compatibility with other resins and the nonionic property does not have an ionic hydrophilic group, it is also preferable for improving the moisture resistance and heat resistance.

As the anionic hydrophilic group, those having a hydroxyl group for introducing into polyisocyanate and a carboxylic acid group for imparting hydrophilicity are preferable. Examples thereof include glycolic acid, lactic acid, tartaric acid, citric acid, oxybutyric acid, oxyvaleric acid, hydroxypivalic acid, dimethylolacetic acid, dimethylolpropanoic acid, dimethylolbutanoic acid, and polycaprolactone having a carboxylic acid group. Organic amine compounds are preferred for neutralizing carboxylic acid groups. For example, ammonia, methylamine, ethylamine, propylamine, isopropylamine, butylamine, 2-ethylhexylamine, cyclohexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine. , Linear, branched 1,2 or tertiary amines with 1 to 20 carbon atoms such as ethylenediamine, cyclic amines such as morpholin, N-alkylmorpholin, pyridine, monoisopropanolamine, methylethanolamine, methylisopropanolamine, Examples thereof include hydroxyl group-containing amines such as dimethylethanolamine, diisopropanolamine, diethanolamine, triethanolamine, diethylethanolamine and triethanolamine.

As the nonionic hydrophilic group, the repeating unit of polyethylene glycol one-ended sealed with an alkyl group, ethylene oxide of polypropylene glycol and / or propylene oxide is preferably 3 to 50, and more preferably 5 to 30. If the repeating unit is small, the compatibility with the resin is poor and the haze is increased, and if it is large, the adhesiveness under high temperature and high humidity may be lowered. The blocked isocyanate of the present invention can be added with a nonionic, anionic, cationic or amphoteric surfactant in order to improve water dispersibility. For example, nonionic systems such as polyethylene glycol and polyhydric alcohol fatty acid esters, anionic systems such as fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, sulfosuccinates and alkyl phosphates, and cationic systems such as alkylamine salts and alkylbetaines. Examples thereof include surfactants such as carboxylic acid amine salts, sulfonic acid amine salts, and sulfate ester salts.

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

Other disclosed compounds can be applied and added as means for improving adhesion. Even with other cross-linking agents in order to improve the adhesion durability of the easy-adhesion layer, it becomes possible to further improve the adhesion under high temperature and high humidity. Specific examples of the cross-linking agent include urea-based, epoxy-based, melamine-based, oxazoline-based, and carbodiimide-based. Further, in order to promote the cross-linking reaction, a catalyst or the like can be appropriately used as needed.

(Polyester resin)
The polyester resin used to form the easy-adhesion layer in the present invention may be linear, but more preferably a polyester resin containing a dicarboxylic acid and a diol having a branched structure as constituents. It is preferable to have. The main component of the dicarboxylic acid referred to here is terephthalic acid, isophthalic acid or 2,6-naphthalenedicarboxylic acid, as well as aliphatic dicarboxylic acids such as adipic acid and sebacic acid, terephthalic acid, isophthalic acid, phthalic acid, 2, Examples include aromatic dicarboxylic acids such as 6-naphthalenedicarboxylic acid. Further, the branched glycol is a diol having a branched alkyl group, for example, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-. Methyl-2-butyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n -Hexyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl- 1,3-Propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, and 2,2-di-n- Examples thereof include hexyl-1,3-propanediol.

It can be said that the polyester resin contains the branched glycol component, which is a more preferable embodiment, in the total glycol component in a proportion of preferably 10 mol% or more, more preferably 20 mol% or more. When it is 10 mol% or more, the crystallinity does not become too high, and the adhesiveness of the easy-adhesion layer becomes good, which is preferable. The upper limit of the glycol component in the total glycol component is preferably 80 mol% or less, and more preferably 70% by mass. When it is 80 mol% or less, the concentration of the oligomer as a by-product is suppressed, and the transparency of the easy-adhesion layer is good, which is preferable. Ethylene glycol is most preferable as the glycol component other than the above compounds. In a small amount, diethylene glycol, propylene glycol, butanediol, hexanediol, 1,4-cyclohexanedimethanol or the like may be used.

As the dicarboxylic acid as a constituent component of the polyester resin, terephthalic acid or isophthalic acid is most preferable. In addition to the above dicarboxylic acid, in order to impart water dispersibility to the copolymerized polyester resin, it is preferable to copolymerize 5-sulfoisophthalic acid or the like in a price range of 1 to 10 mol%, for example, sulfoterephthalic acid. Examples thereof include 5-sulfoisophthalic acid and 5-sodium sulfoisophthalic acid. A polyester resin containing a dicarboxylic acid having a naphthalene skeleton may be used, but the quantitative ratio thereof is 5 mol% or less in the total carboxylic acid component in order to suppress the deterioration of the adhesion to the UV ink. It is preferable that it is not used.

As a constituent component of the polyester resin, triol or tricarboxylic acid may be contained to the extent that the characteristics of the polyester resin are not impaired.

The polyester resin may contain a polar group other than the carboxyl group. For example, a metal sulfonic acid base, a phosphoric acid group and the like can be mentioned, and these can have one kind or two or more kinds. As a method for introducing a metal sulfonic acid base, a metal salt such as 5-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5- [4-sulfophenoxy] isophthalic acid or 2-sulfo-1, Dicarboxylic acid or glycol containing a sulfonic acid metal base such as a metal salt such as 4-butanjiol, 2,5-dimethyl-3-sulfo-2,5-hexanediol is the total of the polycarboxylic acid component or the polyol component. Examples thereof include a method of using in the range of 10 mol% or less, preferably 7 mol% or less, more preferably 5 mol% or less. If it exceeds 10 mol%, the hydrolysis resistance of the resin itself and the water resistance of the coating film tend to decrease.

The resin solid content concentration in the coating liquid means the total solid content concentration of the polyester resin, the urethane resin having a polycarbonate structure, and the cross-linking agent. It is desirable to adjust the resin solid content concentration in the coating liquid to 5 to 17%. When the resin solid content concentration is 5% or more, the thickness of the easy-adhesive layer after drying and curing does not become too thin, and various easy-adhesive properties such as UV-curable ink are good, which is preferable. On the other hand, when the resin solid content concentration is 17% or less, sufficient cross-linking property when a cross-linking agent is contained can be obtained, migration of the antistatic agent to other articles or the back surface can be suppressed, and a blocking phenomenon also occurs. It is preferable because it can be suppressed.

When the total solid content contained in the composition for forming the easy-adhesion layer is 100% by mass, it is desirable that the ion-conducting antistatic agent is contained in an amount of 1 to 8% by mass. Antistatic performance can be obtained if the specified range is satisfied. Further, it is a preferable range because the antistatic component does not migrate to other articles or the back surface after the heat treatment and the moisture resistance heat treatment.

When the total of the solid content masses of the polyester resin, the urethane resin having a polycarbonate structure, and the cross-linking agent is 100% by mass, the content of the urethane resin having a polycarbonate structure is preferably 5 to 50% by mass. When the above range is satisfied, the affinity with various materials and UV inks is good and the adhesion can be achieved, which is preferable. Within the above specified range, it is preferable that the antistatic agent has excellent adhesiveness and antistatic performance, and the antistatic agent can suppress the transferability to other articles or the back surface even under heat resistance.

When the total solid content mass of the polyester resin, the urethane resin having a polycarbonate structure, and the cross-linking agent is 100% by mass, the upper limit of the content of the cross-linking agent is preferably 50% by mass. Satisfying the above range is preferable because the crosslinkability of the easy-adhesion layer is enhanced, the affinity with UV ink and the like is improved, and the antistatic property is easily exhibited. Further, the strength of the easy-adhesive layer in the moisture-resistant treatment is maintained, and the antistatic agent is preferable because it can suppress the transferability to other articles and the back surface.

When the total solid content mass of the polyester resin, the urethane resin having a polycarbonate structure, and the three cross-linking agents is 100% by mass, the polyester resin content is preferably 10 to 70% by mass. By satisfying the above range, the affinity with various materials and UV inks is good and the adhesion can be achieved. In particular, it is preferable because the adhesion to the polyester film base material is improved. Further, when a cationic antistatic agent is used, gelation of the coating liquid due to interaction can be suppressed, which is preferable.

(Additive)
In the easy-adhesion layer in the present invention, known additives such as surfactants, Ph adjusters, antioxidants, heat-resistant stabilizers, weather-resistant stabilizers, ultraviolet absorbers, and organics are contained within the range that does not impair the effects of the present invention. Glidants, pigments, dyes, organic or inorganic particles, antistatic agents, nucleating agents and the like may be added.

The above-mentioned surfactant may be used with the expectation of the effects of a solubilizer, a dispersant, an antifoaming agent, a wetting aid and the like. The hydrophilic portion of the surfactant is divided into ionic (cationic, anionic, amphoteric) and nonionic. When used as a water-based coating material, the polyester film used as a base material is used because it has low surface energy and poor wettability. Therefore, it is often used as a surface tension adjusting agent for water-based coating materials and as a wetting aid. Although not particularly limited, the surfactant is preferably one that can lower the surface tension of the coating liquid to 50 yne / cm or less, preferably 40 dyne / cm or less, and promotes wetting to the polyester film, for example, alkyl. Trimethylammonium salt, dialkyldimethylammonium salt, alkylbenzyldimethylammonium salt, monoalkylsulfate, alkylpolyoxyethylene sulfate, alkylbenzenessulfonate, monoalkylphosphate, alkyldimethylamine oxide, alkylcarboxybetaine, polyoxyethylene Examples thereof include alkyl ether, fatty acid sorbitan ester, alkyl polyglucoside, fatty acid diethanolamide, and alkyl monoglyceryl ether, and among them, polyether-modified silicone is preferable.

The amount of the surfactant added is preferably 0.1% by mass or more and 1.0% by mass or less when the total solid content in the coating liquid is 100% by mass. More preferably, it is in the range of 0.2% by mass to 0.8% by mass. When it is 0.1% by mass or more, a wettability effect as a surfactant can be obtained, which is preferable. Further, when it is 1.0% by mass or less, the easy adhesiveness is kept good and it is preferable.

A pH adjuster may be used as the additive. Mineral acids such as hydrochloric acid, nitric acid and sulfuric acid and organic acids such as oxalic acid, formic acid, citric acid and acetic acid are used as the acid for adjusting the pH, and sodium carbonate, sodium hydrogencarbonate, sodium phosphinate and the like are used for alkali adjustment. Be done. The adjustment with the water-based coating material is preferably neutral, preferably in the range of pH 5 to 9, and more preferably adjusted to pH 6 to 8.5. If the pH is 5 or less, the coating machine may be corroded, and the effect of promoting the dissociation of the blocking agent when the blocking isocyanate is selected as the cross-linking agent is reduced. Further, when the pH is 9 or more, the polyester resin used as the resin binder or the like causes hydrolysis and impairs the adhesiveness and durability, which is not preferable.

In order to reduce the glossiness of the surface of the easy-adhesion layer, inert particles may be contained in the easy-adhesion layer.

The easy-adhesive layer may also contain lubricant particles in order to impart slipperiness, mattness, ink absorbency and the like to the surface. The particles may be inorganic particles or organic particles, and are not particularly limited. (1) Silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, etc. Barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, zirconium oxide, titanium dioxide, aluminum silicate, silica soil, calcium silicate, aluminum hydroxide, calcium carbonate, magnesium carbonate, calcium phosphate, magnesium hydroxide, barium sulfate, etc. Inorganic particles, (2) Acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene / acrylic, styrene / butadiene, polystyrene / acrylic, polystyrene / isoprene, polystyrene / isoprene, methylmethacrylate / Butyl methacrylate-based, melamine-based, polycarbonate-based, urea-based, epoxy-based, urethane-based, phenol-based, diallyl phthalate-based, polyester-based, etc. In addition, silica is particularly preferably used.

The average particle size of the inert particles is preferably 0.1 to 2.4 μm, more preferably 0.3 to 2.0 μm. When the average particle size of the inert particles is 0.04 μm or less, the glossiness of the film surface may increase. On the contrary, if it exceeds 2.4 μm, the particles tend to fall off from the easy-adhesive layer and cause powder to fall off in various processes such as when the film is run.

The average particle size can be determined as a result of morphological observation with a microscope using a scanning electron microscope, a transmission electron microscope, or the like. Specifically, the average value of the diameters of 20 particles arbitrarily selected in these microscopic observations is adopted. The shape of the particles is not particularly limited as long as it satisfies the object of the present invention, and spherical particles and amorphous non-spherical particles can be used. The particle size of the amorphous particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is a value obtained by dividing the observed particle area by π, calculating the square root, and doubling it.

When it is desired to increase the glossiness of the surface of the easy-adhesion layer, it is also preferable not to contain particles in the easy-adhesion layer.

(Manufacturing of easy-adhesive polyester film)
The method for producing an easily adhesive polyester film of the present invention is arbitrary and is not particularly limited. For example, after melting a mixture having the above-mentioned composition and extruding it into a sheet to form an unstretched film, this method is used. A general method of stretching an unstretched film can be used.

In the easily adhesive polyester film of the present invention, a thermoplastic resin incompatible with the polyester resin may be dispersed in the polyester resin in the step of melting and extruding the film raw material. In the examples of the present invention, the polyester resin and the thermoplastic resin incompatible with the polyester resin are supplied in the form of pellets, but the present invention is not limited thereto.

The raw materials to be charged into the extruder for melt molding into a film are prepared by mixing pellets of these resins according to the desired composition. However, when a polyester resin and a polyolefin resin are used as the raw materials for the polyester film of the present invention, the specific gravity of the resins differs greatly between the two, so a device is devised so that the pellets once mixed are not segregated in the process of being supplied to the extruder. It is preferable to add. As a preferable method for preventing segregation, a method of kneading and pelletizing a part or all of the raw material resin in advance to obtain a masterbatch pellet can be mentioned. Although this method is used in the examples of the present invention, it is not particularly limited as long as it does not interfere with the effect of the present invention.

Further, in the extrusion of a mixed system of these polyester resins and a resin incompatible with the polyester resin, even after the mixture is mixed in a molten state and finely dispersed, it reaggregates due to the function of reducing the interfacial energy of the resin. Has the property of This is a phenomenon in which the cavity-developing agent is coarsely dispersed when the unstretched film is extruded, which hinders the development of desired physical properties.

In order to prevent this, when forming the mixed film as described above, it is preferable to finely disperse the cavity-developing agent in advance using a twin-screw extruder having a higher mixing effect. If this is difficult, it is also preferable to supply the raw material resin from the extruder to the feed block or the die as an auxiliary means via a static mixer. As the static mixer used here, a static mixer, an orifice or the like can be used. However, when these methods are adopted, care must be taken because the heat-deteriorated resin may stay in the melt line.

In the incompatible resin once dispersed in the polyester resin in the form of fine particles, the reaggregation of the incompatible resin tends to proceed with time under the molten state of low shear, so that the melt from the extruder to the die Reducing the residence time in the line is the fundamental solution. In the present invention, the residence time in the melt line is preferably 30 minutes or less, more preferably 15 minutes or less.

The conditions for stretching and orienting the unstretched film obtained as described above are closely related to the physical characteristics of the film. In the following, the stretching and orientation conditions will be described by taking as an example the most common sequential biaxial stretching method, particularly a method of stretching an unstretched film in the longitudinal direction and then in the width direction.

In the longitudinal stretching step, a roll heated to 80 to 120 ° C. is stretched 2.5 to 5.0 times in the longitudinal direction to obtain a uniaxially stretched film. As the heating means, a method using a heating roll or a method using a non-contact heating method may be used, or they may be used in combination. Next, the uniaxially stretched film is introduced into the tenter and stretched 2.5 to 5.0 times at a temperature of (Tm-10 ° C.) or less in the width direction. However, Tm means the melting point of polyester.

Further, the above biaxially stretched film is heat-treated as necessary. The heat treatment is preferably performed in a tenter, preferably in the range of (Tm-60 ° C.) to Tm.

The easy-adhesive layer can be provided after the film is manufactured or in the manufacturing process. In particular, from the viewpoint of productivity, it is preferable to apply the coating liquid to at least one side of the PET film after unstretched or uniaxially stretched at any stage of the film manufacturing process to form an easy-adhesion layer.

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

In the present invention, the thickness of the easy-adhesion layer can be appropriately set in the range of 0.001 to 2.00 μm, but the range of 0.01 to 1.00 μm is preferable in order to achieve both processability and adhesiveness. , More preferably 0.02 to 0.80 μm, still more preferably 0.05 to 0.50 μm. When the thickness of the easy-adhesion layer is 0.001 μm or more, the adhesiveness is good, which is preferable. When the thickness of the easy-adhesive layer is 2.00 μm or less, it is preferable because it can suppress the transfer of other antistatic agents to other articles and the back surface.

Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. First, the evaluation method used in the present invention will be described below.

(1) Antistatic property Surface intrinsic resistance value Three films were cut into 5.00 cm squares and used as samples. The surface specific resistance value was measured using a surface resistance measuring instrument (High Resta MCP-HT800 manufactured by Nitto Seiko Analyc) at an applied voltage of 500 V and 23 ° C. and 65% humidity in accordance with JIS K6911, and used as the average value. ..

(2) Evaluation of Easy Adhesive Layer Surface and Other Surface Transferability under 50 ° C. Pressurized Environment Three films were cut into 5.00 cm squares and used as samples. This is superposed on the polyester film E5001 (thickness 50 μm) manufactured by Toyobo Co., Ltd. and the surface of the easy-adhesion layer of the sample, and using the dry oven DVS602 manufactured by Yamato Kagaku Co., Ltd., 1 kg / cm at 50 ° C. and ³ under pressure. Retained for days. Using a surface resistance measuring instrument (Nitto Seiko Analyc Hiresta MCP-HT800), the surface intrinsic resistance value of the surface of the easy-adhesion layer of the sample and the surface of the contacted Toyobo polyester film E5001 was measured at an applied voltage of 500 V, at 23 ° C and 65% humidity. The average value was calculated by measuring 3 sheets each in accordance with JIS K6911.
For the easy-adhesion layer surface of the sample,
〇: 1.0 × 10 ¹³ Ω / sq or less ×: 1.0 × 10 ¹³ Ω / sq or more For the contacted surface of E5001
〇: 1,0 × 10 ¹⁴ Ω / sq or more ×: 1.0 × 10 ¹⁴ Ω / sq or less.

(3) Evaluation of easy-adhesion layer surface and transferability to other surfaces under pressure in a moisture-resistant heat environment Three films were cut into 5 cm squares and used as samples. This is superposed on the polyester film E5001 (thickness 50 μm) manufactured by Toyobo Co., Ltd. and the surface of the easy-adhesion layer of the sample, and using the constant temperature and humidity controller IG400 manufactured by Yamato Scientific Co., Ltd., 1 kg at 60 ° C. and 90% temperature and humidity. The one held for 2 days under the pressure of / cm ² and the one held for 3 days were prepared. The surface intrinsic resistance value of the easy-adhesion layer of the sample and the surface of the contacted Toyobo polyester film E5001 was measured using a surface resistance measuring instrument (Nitto Seiko Analyc Hiresta MCP-HT800) at an applied voltage of 500 V and 23 ° C. and 65% humidity. The average value was calculated by measuring 3 sheets each according to JIS K6911.
As for the surface of the easy-adhesion layer of the sample, the one held overlaid for 3 days was measured.
〇: 1.0 × 10 ¹³ Ω / sq or less ×: 1.0 × 10 ¹³ Ω / sq or more For the contacted surface of E5001, both the two-day superposition and the three-day superposition were measured. death,
〇: The one overlapped for 3 days is 1.0 × 10 ¹⁴ Ω / sq or more △: The one overlapped for 3 days is less than 1.0 × 10 ¹⁴ Ω / sq, and the one overlapped for 2 days is 1 .0 × 10 ¹³ Ω / sq or more ×: The result of stacking for 2 days was evaluated as less than 1.0 × 10 ¹³ Ω / sq.

(4) Adhesion to UV ink A printing machine [(Co., Ltd.) using UV ink [T & K TOKA Co., Ltd., trade name "BEST CURE UV161 Ai S"] on the easy-adhesion layer of easy-adhesion polyester film. ) Ming Seisakusho, trade name "RI tester"] was printed, and then the film coated with the ink layer was irradiated with ultraviolet rays of 40 mJ / cm ² using a high-pressure mercury lamp to cure the ultraviolet curable ink. .. Next, using a cellophane adhesive tape (CT405AP-24) manufactured by Nichiban, a width of 24 mm and a length of 50 mm are cut out and completely adhered with a handy rubber roller so that air does not enter the surface of the ink layer. Then, the cellophane adhesive tape was peeled off vertically, and the remaining area of the print layer was observed in the area of 24 mm × 50 mm, and the judgment was made according to the following criteria.
◯: Passed when the remaining area of the print layer was 99% or more of the whole.
Δ: Passed when the remaining area of the printed layer was 90% or more and less than 99% of the whole.
X: The remaining area of the print layer was less than 90% of the total, and the result was rejected.

(Cation-based antistatic agent A-1)
An esterification reaction was carried out at 100 ° C. using 116 g of N, N-dimethyl-1,3-propanediamine and 285 g of stearic acid having 17 carbon atoms in a nitrogen atmosphere for 10 hours, and tetrahydrofuran was added as a quaternizing solvent, and the target amine was added. A specified amount of dimethyl sulfate was added to the mixture, and the mixture was reacted at 70 ° C. for about 10 hours. After the reaction, the solvent was distilled off under reduced pressure, and then isopropanol was added to adjust the solid content concentration to a desired concentration to obtain an isopropanol solution of a cationic antistatic agent (A-1) having a quaternary ammonium etosulfate salt. rice field.

(Cation-based antistatic agent A-2)
Other A-1 treatments were carried out in the same manner using 89 g of dimethylaminoethanol and 228 g of myristic acid having 14 carbon atoms to obtain a cationic antistatic agent (A-2) solution having a quaternary ammonium etosulfate salt. ..

(Cation-based antistatic agent A-3)
Esterification reaction was carried out at 200 ° C. using 89 g of dimethylaminoethanol and 354 g of tricosyl acid having 23 carbon atoms in a nitrogen atmosphere for 10 hours, tetrahydrofuran was added as a quaternizing solvent, and a specified amount of dimethyl sulfate was added to the target amine at 70 ° C. The reaction was carried out for about 10 hours. Other treatments similar to those for A-1 were carried out to obtain an isopropanol solution of a cationic antistatic agent (A-3) having a quaternary ammonium etosulfate salt.

(Anionic antistatic agent A-4)
Sodium dodecylbenzene sulfonic acid salt (TB702 manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) was used.

(Quaternary Cationic Chlorine Antistatic Agent A-5)
Lauryltrimethylammonium chloride (Catiogen (registered trademark) TML manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used.

(Polymerization of urethane resin B-1 having a polycarbonate structure)
22 parts by mass of 4,4-dicyclohexylmethane diisocyanate and 20 parts by mass of polyethylene glycol monomethyl ether having a number average molecular weight of 700 in a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen introduction tube, a silica gel drying tube, and a thermometer. , 53 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 2100, 5 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added and stirred at 75 ° C. for 3 hours under a nitrogen atmosphere to prepare a reaction solution. It was confirmed that the predetermined amine equivalent was reached. Next, 16 parts by mass of a polyisocyanate compound (Duranate TPA, trifunctional) having an isocyanurate structure made from hexamethylene diisocyanate was added, and the mixture was stirred at 75 ° C. for 1 hour under a nitrogen atmosphere to prepare a reaction solution. Was confirmed to have reached the prescribed amine equivalent. Then, the temperature of the reaction solution was lowered to 50 ° C., and 7 parts by mass of methyl ethyl ketooxime was added dropwise. After lowering the temperature of this reaction solution to 40 ° C., a polyurethane prepolymer solution was obtained. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and the polyurethane prepolymer solution was added and water-dispersed while stirring and mixing at 2000 min ^-1 . .. Then, under reduced pressure, acetone and a part of water were removed to prepare a solution of the water-dispersible urethane resin (B-1) having a solid content of 35% by mass.

(Polymerization of urethane resin B-2 having a polycarbonate structure)
In a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen introduction tube, a silica gel drying tube, and a thermometer, 25 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 5 parts by mass of dimethylol propanoic acid, and a number average molecular weight of 2600. 52 parts by mass of polyhexamethylene carbonate diol, 6 parts by mass of neopentyl glycol, and 84.00 parts by mass of acetone as a solvent were added and stirred at 75 ° C. for 3 hours under a nitrogen atmosphere to bring the reaction solution to a predetermined amine equivalent. I confirmed that it was reached. Next, 18 parts by mass of a polyisocyanate compound (Duranate TPA, trifunctional) having an isocyanurate structure made from hexamethylene diisocyanate was added, and the mixture was stirred at 75 ° C. for 1 hour under a nitrogen atmosphere to prepare a reaction solution. Was confirmed to have reached the prescribed amine equivalent. Then, the temperature of the reaction solution was lowered to 50 ° C., and 8 parts by mass of methyl ethyl ketooxime was added dropwise. After lowering the temperature of this reaction solution to 40 ° C., 5.17 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring, adjusted to 25 ° C., and the polyurethane prepolymer solution was added and water-dispersed while stirring and mixing at 2000 min ^-1 . .. Then, under reduced pressure, acetone and a part of water were removed to prepare a solution of the water-dispersible urethane resin (B-2) having a solid content of 35% by mass.

(Polymerization of urethane resin B-3 containing no polycarbonate polyol component)
75 parts by mass of a polyester polyol having a molecular weight of 5000 containing terephthalic acid, isophthalic acid, ethylene glycol, and neopentyl glycol, 30 parts by mass of hydrogenated m-xylylene diisocyanate, 7 parts by mass of ethylene glycol, and 6 dimethylolpropionic acid. 84.00 parts by mass of acetone and 84.00 parts by mass of acetone were added as a solvent, and the mixture was stirred at 75 ° C. for 3 hours under a nitrogen atmosphere, and it was confirmed that the reaction solution reached a predetermined amine equivalent. After lowering the temperature of this reaction solution to 40 ° C., 5.17 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, to a reaction vessel equipped with a homodisper capable of high-speed stirring, 450 g of water was added, adjusted to 25 ° C., and the polyurethane prepolymer solution was added while stirring and mixing at 2000 min ^-1 . Water dispersed. Then, under reduced pressure, acetone and a part of water were removed to prepare a solution of the water-dispersible urethane resin (B-3) having a solid content of 35% by mass.

(Preparation of Polyurethane Block Isocyanate (B-4) with Polyester Structure)
To 200 parts by mass of polyester (molecular weight 2000) of 2 mol adduct of ethylene oxide of bisphenol A and maleic acid, 33.6 parts by mass of hexamethylene diisocyanate was added, and the reaction was carried out at 100 ° C. for 2 hours. Next, the temperature of the system was once lowered to 50 ° C., 73 parts by mass of a 30% aqueous sodium bisulfite solution was added, the mixture was stirred at 45 ° C. for 60 minutes, diluted with 718 parts by mass of water, and blocked polyisulfate (B-4). ), An aqueous dispersion having a solid content of 20.0% by mass was obtained. The blocked isocyanate cross-linking agent has 2 functional groups and an NCO equivalent of 1300.

(Polymerization of Blocked Isocyanate Crosslinking Agent C-1)
66.04 parts by mass of polyisocyanate compound (Duranate TPA, manufactured by Asahi Kasei Chemicals Co., Ltd.) using hexamethylene diisocyanate as a raw material in a flask equipped with a stirrer, a thermometer, and a reflux condenser, N-methylpyrrolidone 17.50. 95 parts by mass of 3,5-dimethylpyrazole (dissociation temperature: 120 ° C., boiling point: 218 ° C.) was added dropwise to the mass portion, and the mixture was kept at 70 ° C. for 1 hour under a nitrogen atmosphere. Then, 30 parts by mass of dimethylolpropaneic acid was added dropwise. After measuring the infrared spectrum of the reaction solution and confirming that the absorption of the isocyanate group disappeared, 5.59 parts by mass of N, N-dimethylethanolamine and 132.5 parts by mass of water were added, and the blocked polyisocyanate (C-) was added. An aqueous dispersion having a solid content of 40% by mass in 1) was obtained. The blocked isocyanate cross-linking agent has 4 functional groups and an NCO equivalent of 280.

(Polymerization of blocked isocyanate cross-linking agent C-2)
100 parts by mass of a polyisocyanate compound (Duranate TPA manufactured by Asahi Kasei Chemicals Co., Ltd.) using hexamethylene diisocyanate as a raw material in a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, 55 parts by mass of propylene glycol monomethyl ether acetate, polyethylene. 30 parts by mass of glycol monomethyl ether (average molecular weight 750) was charged and kept at 70 ° C. for 4 hours under a nitrogen atmosphere. Then, the temperature of the reaction solution was lowered to 50 ° C., and 47 parts by mass of methyl ethyl ketooxime was added dropwise. The infrared spectrum of the reaction solution was measured to confirm that the absorption of isocyanate groups had disappeared, and 210 parts by mass of water was added to obtain an aqueous dispersion having a solid content of 40% by mass of the oxime-blocked isocyanate cross-linking agent (C-2). rice field. The blocked isocyanate cross-linking agent has 3 functional groups and an NCO equivalent of 170.

(Polyester resin D-1 polymerization)
194.2 parts by mass of dimethylterephthalate, 184.5 parts by mass of dimethylisophthalate, 14.8 parts by mass of dimethyl-5-sodium sulfoisophthalate in a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux cooler. , 185 parts by mass of neopentyl glycol, 188 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate were charged, and a transesterification reaction was carried out at a temperature of 160 ° C to 220 ° C for 4 hours. Then, the temperature was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and then the reaction was carried out under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolymerized polyester resin (D-1). The obtained copolymerized polyester resin (D-1) was pale yellow and transparent. The reduced viscosity of the copolymerized polyester resin (D-1) was measured and found to be 0.40 dl / g. The glass transition temperature by DSC was 65 ° C.

(Adjustment of polyester aqueous dispersion Dw-1)
25 parts by mass of the copolymerized polyester resin (D-1) and 10 parts by mass of ethylene glycol n-butyl ether were placed in a reactor equipped with a stirrer, a thermometer and a reflux device, and heated at 110 ° C. and stirred to dissolve the resin. After the resin was completely dissolved, 65 parts by mass of water was gradually added to the polyester solution with stirring. After the addition, the liquid was cooled to room temperature with stirring to prepare a milky white polyester aqueous dispersion (Dw-1) having a solid content of 25% by mass.

(Polyester resin D-2 polymerization)
194.2 parts by mass of dimethylterephthalate, 184.5 parts by mass of dimethylisophthalate, 14.8 parts by mass of dimethyl-5-sodium sulfoisophthalate in a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser. , 233.5 parts by mass of diethylene glycol, 136.6 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate were charged, and an ester exchange reaction was carried out at a temperature of 160 ° C to 220 ° C for 4 hours. Then, the temperature was raised to 255 ° C., the temperature of the reaction system was gradually reduced, and then the reaction was carried out under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolymerized polyester resin (D-2). The obtained copolymerized polyester resin (D-2) was pale yellow and transparent. The reduced viscosity of the copolymerized polyester resin (D-2) was measured and found to be 0.70 dl / g. The glass transition temperature by DSC was 40 ° C.

(Adjustment of polyester aqueous dispersion Dw-2)
25 parts by mass of the copolymerized polyester resin (D-2) and 10 parts by mass of ethylene glycol n-butyl ether were placed in a reactor equipped with a stirrer, a thermometer and a reflux device, and heated at 110 ° C. and stirred to dissolve the resin. After the resin was completely dissolved, 65 parts by mass of water was gradually added to the polyester solution with stirring. After the addition, the liquid was cooled to room temperature with stirring to prepare a milky white polyester aqueous dispersion (Dw-2) having a solid content of 25% by mass.

(Example 1)
The solid content of the compound constituting the coating layer in the coating liquid is as follows.
The total solid content contained in the coating layer is 100% by mass.
-Cation-based antistatic agent A-1: 6.2% by mass
-Urethane resin having a polycarbonate structure B-1: 22.8% by mass
-Blocked isocyanate cross-linking agent C-1: 22.8% by mass
-Polyester resin D-1: 45.4% by mass
-Silicone-based surfactant: 0.4% by mass
-PH regulator (sodium hydrogen carbonate): 2.4% by mass
The solid content mass ratio of the urethane resin (B-1) / cross-linking agent (C-1) / polyester resin (D-1) is 25/25/50.

(1) Production of polyester film containing white cavities (F-1)
(Preparation of master pellets)
Polymethylpentene resin with melt viscosity (ηO) of 1,300 poise (manufactured by Mitsui Chemicals, DX820) 60% by mass, polystyrene resin with melt viscosity (ηS) of 3,900 poise (manufactured by Nippon Police Co., Ltd., G797N) 20 mass % And 20% by mass of polypropylene resin (Grand Polymer, J104WC) having a melt viscosity of 2,000 poise was pellet-mixed and supplied to a bent twin-screw extruder whose temperature was adjusted to 285 ° C. and pre-kneaded. .. The molten resin was continuously supplied to a vent-type single-screw kneader, kneaded and extruded, and the obtained strands were cooled and cut to prepare a cavity-developing agent master pellet (M1).

Further, 50% by mass of anatase-type titanium dioxide particles (TA-300, manufactured by Fuji Titanium Industry Co., Ltd.) having an average particle size of 0.3 μm is mixed with 50% by mass of a polyethylene terephthalate resin having an intrinsic viscosity of 0.62 dl / g manufactured by a known method. The mixture was supplied to a vent type twin-screw extruder and pre-kneaded. This molten resin was continuously supplied to a vent type uniaxial kneader, kneaded and extruded. The obtained strands were cooled and cut to prepare titanium dioxide-containing master pellets (M2).

(Preparation of film raw material)
81% by mass of the polyethylene terephthalate resin having an intrinsic viscosity of 0.62 dl / g vacuum-dried at 140 ° C. for 8 hours, 9% by mass of the master pellet (M1) vacuum-dried at 90 ° C. for 4 hours, and the above. 10% by mass of the master pellet (M2) was pellet-mixed to obtain a film raw material (G1).

(Preparation of unstretched film)
70% by mass of the same polyethylene terephthalate resin used for the film raw material (G1) and 30% by mass of the master pellet (M2) are mixed in the extruder for the B layer in which the temperature of the film raw material (G1) is adjusted to 285 ° C. Was separately supplied to an extruder for layer A whose temperature was adjusted to 290 ° C. The molten resin discharged from the extruder for the B layer is guided to the feedbook via the orifice, and the resin discharged from the extruder for the A layer is guided to the feedbook via the static mixer, and the layer (B layer) composed of the film raw material (G1) is introduced. A layer (A layer) composed of the polyethylene terephthalate resin and the master pellet (M2) was laminated in the order of A layer / B layer / A layer.

This molten resin was co-extruded from a T-die into a sheet on a cooling roll whose temperature was adjusted to 25 ° C., and was closely solidified by an electrostatic application method to prepare an unstretched film having a thickness of 510 μm. The discharge amount of each extruder was adjusted so that the thickness ratio of each layer was 1: 8: 1. At this time, the time for the molten resin to stay in the melt line was about 12 minutes, and the shear rate received from the T-die was about 150 / sec.

(Preparation of biaxially stretched film)
The obtained unstretched film is uniformly heated to 65 ° C. using a heating roll, and 3.4 between two pairs of nip rolls (low speed roll: 2 m / min, high speed roll: 6.8 m / min) having different peripheral speeds. It was stretched twice vertically. At this time, as an auxiliary heating device for the film, an infrared heater (rated output: 20 W / cm) provided with a gold reflective film in the middle of the nip roll was installed at a position 1 cm from the film surface facing both sides of the film and heated. .. Using the above-mentioned coating configuration, the uniaxially stretched film thus obtained was coated with a WET coating amount of 7 g / m ² by the reverse gravure coating method, and then guided to a tenter and dried. Easy adhesion with a thickness of 50 μm by heating to 150 ° C., laterally stretching 3.7 times, fixing the width, heat-treating at 220 ° C. for 5 seconds, and further relaxing at 200 ° C. by 4% in the width direction. Obtained a polyester film. This film has excellent whiteness, an apparent density of 1.10 g / cm ³ due to the appearance of cavities, an optical density of 0.8, and an easily adhesive polyester film with a coating layer thickness of 0.12 g / m ² after drying. Obtained. The evaluation results are shown in Table 1.

(Examples 2 to 26)
An easily adhesive polyester film was obtained in the same manner as in Example 1 except that the coating layer composition in Table 1 was changed.

(Example 27)
The solid content of the compound constituting the coating layer in the coating liquid is as follows.
The total solid content contained in the coating layer is 100% by mass.
Colloidal silica particles (E-1) (average particle diameter: 450 nm): 48.8% by mass
-Cation-based antistatic agent A-1: 2.1% by mass
-Urethane resin having a polycarbonate structure B-1: 12.2% by mass
-Blocked isocyanate cross-linking agent C-1: 12.2% by mass
-Polyester resin D-1: 24.4% by mass
-Silicone-based surfactant: 0.1% by mass
-PH regulator (sodium hydrogen carbonate): 0.2% by mass
The mass ratio of the urethane resin (B-1) / cross-linking agent (C-1) / polyester resin (D-1) is 25/25/50 /.
An easily adhesive polyester film having a coating layer thickness of 0.55 g / m ² after drying was obtained in the same manner as in Example 1 except that the coating layer was configured and the WET coating amount was changed to 10 g / m ² . A coating layer having a matte feeling with a gloss value of 9.0 at 60-degree specular reflection on the surface of the coating layer was obtained.

(Example 28)
The solid content of the compound constituting the coating layer in the coating liquid is as follows.
The total solid content contained in the coating layer is 100% by mass.
-Benzocuanamine particles (E-2) (average particle size: 1.2 μm): 38.3% by mass
-Cation-based antistatic agent A-1: 2.1% by mass
-Urethane resin with polycarbonate structure B-1: 14.8% by mass
-Blocked isocyanate cross-linking agent C-1: 14.8% by mass
-Polyester resin D-1: 29.6% by mass
-Silicone-based surfactant: 0.1% by mass
-PH regulator (sodium hydrogen carbonate): 0.3% by mass
The mass ratio of the urethane resin (B-1) / cross-linking agent (C-1) / polyester resin (D-1) is 25/25/50 /.
An easily adhesive polyester film having a coating layer thickness of 0.93 g / m ² after drying was obtained in the same manner as in Example 1 except that the coating layer was configured and the WET coating amount was changed to 12 g / m ² . A coating layer having a matte feeling with a gloss value of 14.0 at 60-degree specular reflection on the surface of the coating layer was obtained.

(Example 29)
An easily adhesive polyester film was obtained in the same manner as in Example 27 except that the coating layer composition in Table 1 was changed.

(Example 30)
An easily adhesive polyester film was obtained in the same manner as in Example 28 except that the coating layer configuration was changed to that shown in Table 1.

(Example 31)
The solid content of the compound constituting the coating layer in the coating liquid is as follows.
The total solid content contained in the coating layer is 100% by mass.
Colloidal silica particles E-3 (average particle diameter: 100 nm): 1.6% by mass
-Cation-based antistatic agent A-1: 6.2% by mass
-Urethane resin having a polycarbonate structure B-1: 25.3% by mass
-Blocked isocyanate cross-linking agent C-2: 10.8% by mass
-Polyester resin D-1: 54.2% by mass
-Silicone-based surfactant: 0.4% by mass
-PH regulator: 1.6% by mass (sodium hydrogen carbonate)
The mass ratio of the urethane resin (B-1) / cross-linking agent (C-2) / polyester resin (D-1) is 28/12/60 /.

(2) Production of polyester film containing virtually no particles (F-2)
As a film raw material polymer, PET resin pellets having an intrinsic viscosity (solvent: phenol / tetrachloroethane = 60/40) of 0.62 dl / g and substantially no particles are prepared at 135 ° C. under a reduced pressure of 133 Pa. Dry for hours. Then, it was supplied to an extruder, melt-extruded into a sheet at about 280 ° C., and rapidly cooled and adhered and solidified on a rotary cooling metal roll maintained at a surface temperature of 20 ° C. to obtain an unstretched PET sheet.
This unstretched PET sheet was heated to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction by the roll group having a peripheral speed difference to obtain a uniaxially stretched PET film. Next, using the coating liquid composition based on the solid content, the film was applied by the reverse gravure coating method so that the WET coating amount was 7 g / m ² , and then guided to a tenter and heated to 150 ° C. while drying, 3.7 times. The film was laterally stretched, fixed in width, heat-treated at 220 ° C. for 5 seconds, and further relaxed by 4% in the width direction at 200 ° C. to obtain an easily adhesive polyester film having a film thickness of 50 μm. This film has excellent transparency, an apparent specific gravity of 1.42 g / cm ³ , a total light transmittance of 91%, and an easily adhesive polyester film having a coating layer thickness of 0.12 g / m ² after drying. ..

(Comparative Examples 1 to 7)
A polyester film was obtained in the same manner as in Example 1 except that the coating layer composition in Table 1 was changed.

According to the easily adhesive polyester film of the present invention, it is possible to provide labels, stickers, etc. with excellent mass productivity, and these are excellent in antistatic properties even when used under storage in a moisture-resistant heat environment, and the surface quality of the easy-adhesive layer changes. It is possible to provide a small amount of easy-adhesive polyester film.

Claims (4)

The easy-adhesion layer has an easy-adhesion layer on at least one surface of the polyester film, and the composition containing an ion-conducting antistatic agent, a polyester-based resin, and a polycarbonate urethane resin is cured on the easy-adhesion layer to form a surface of the easy-adhesion layer. The surface intrinsic resistance value is 1.0 × 10 ¹³ Ω / sq or less, and the surface of the easy-adhesion layer is brought into contact with another polyester film and held at 50 ° C., 1 kg / cm ² for 3 days under pressure, and then the easy-to-adhere. An easily adhesive polyester film having a surface intrinsic resistance value of 1.0 × 10 ¹⁴ Ω / sq or more on the surface of the other polyester film that was in contact with the surface of the adhesive layer. The surface intrinsic resistance value of the surface of the easy-adhesive layer is 1.0 after the surface of the easy-adhesive layer is brought into contact with another polyester film and held at 60 ° C. and 90% temperature and humidity at 1 kg / cm for ² days under pressure. × 10 ¹³ Ω / sq or less, the easy-adhesive layer after contacting another polyester film with the surface of the easy-adhesive layer and holding it at 60 ° C. and 90% temperature and humidity at 1 kg / cm for 2 days under ² pressure. The easily adhesive polyester film according to claim 1, wherein the surface intrinsic resistance value of the surface of another polyester film that has been in contact with the surface is 1.0 × 10 ¹³ Ω / sq or more. The easily adhesive polyester film according to claim 1 or 2, wherein the solid content of the ion-conducting antistatic agent is 1 to 8% by mass when the total solid content contained in the composition is 100% by mass. The easily adhesive polyester film according to any one of claims 1 to 3, wherein the total solid content contained in the composition is 100% by mass, and the cross-linking agent is contained in an amount of 0 to 50% by mass as a solid content.