JPH08281890A - Laminated polyester film and sublimation type thermal transfer material - Google Patents

Abstract

PURPOSE: To obtain a transfer image excellent in the close adhesiveness with a sublimation type ink layer and not generating over-transfer by forming an easy adhesive layer by using an acrylic resin copolymerized with a compd. having a carboxyl group and/or a salt thereof within a specific wt.% range and a melamine crosslinking agent contained in amt. of specific % by wt. of the acrylic resin as main constitutional components. CONSTITUTION: A laminated polyester film is obtained by providing an easy adhesive layer on at least the single surface of a polyester film. The easy adhesive layer contains an acrylic resin copolymerized with 3-40wt.% of a compd. having a carboxyl group and/or a salt thereof and a melamine crosslinking agent as main constitutional components and the melamine crosslinking agent is contained in an amt. of 0.1-40 pts.wt. per 100 pts.wt. of the acrylic resin. The easy adhesive layer is provided by coating the polyester film with an adhesive before the completion of crystal orientation and subsequently completing the crystal orientation of the film by stretching and heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyester film and a sublimation-type heat-sensitive transfer material. More specifically, it has excellent adhesion to a sublimation-type ink layer and does not cause over-transfer of the sublimation-type ink. It concerns materials.

[0002]

2. Description of the Related Art Polyester biaxially oriented films have excellent properties such as mechanical properties, dimensional stability, electrical properties, heat resistance, transparency, etc. It is widely used as a base film for many applications such as photographic materials and graphic arts materials. In particular, in recent years, it has shown remarkable elongation as a base film of a heat-sensitive transfer material for OA and FA.

The heat-sensitive transfer materials are roughly classified into those in which an ink layer, in which various pigments are mixed in a binder such as wax, is melted by heat and transferred to a transfer paper, and a dye having a heat sublimation property in the binder. In some cases, only the dye is sublimated by heat and absorbed by the receiving layer of the transferred paper to form a gradation image. Among the above, the sublimation type thermal transfer material sublimates only the dye, therefore, high adhesion is required between the binder and the base film, and it is important that the adhesion is not particularly deteriorated due to environmental change or aging, When the adhesiveness is insufficient, a phenomenon called so-called over-transfer occurs in which the dye-containing resin layer is transferred to the transfer paper.

Generally, the surface of the biaxially oriented polyester film has a high degree of crystallographic orientation, so that the adhesiveness is poor, and even if the sublimation type ink layer is directly applied, it does not adhere at all. Therefore, in order to strengthen the adhesion to the sublimation type ink layer, corona discharge treatment under various gas atmosphere on the film surface,
Physical treatments such as ultraviolet irradiation treatment and plasma treatment, chemical treatments with alkali, amine, trichloroacetic acid, phenols, etc., or treatment methods using these in combination have been attempted, but all of them have sufficient adhesion. Not not. It is also widely used because of the advantages of easy adhesion of the polyester film surface by primer treatment, such as processing process, work safety, and maintaining high quality of processed film products. A method of performing treatment (for example, coating a water-based paint such as polyester resin, acrylic resin, urethane resin, and then stretching to form a coating layer) is considered to be effective in terms of process simplification and manufacturing cost, and is being actively implemented. There is.

For example, a method of individually applying a polyester resin or an acrylic resin is known.

[0006]

However, the above-mentioned conventional technique has the following problems. When water-soluble or water-dispersible polyester resin or acrylic resin is laminated, there is a problem that sufficient adhesion cannot be obtained, and the original color density and transferability when transferred to receiving paper are insufficient. .

The present invention solves these drawbacks and provides a laminated polyester film and a sublimation-type heat-sensitive transfer material which have excellent adhesion to a sublimation-type ink layer and obtain an excellent transferred image without overtransfer. .

[0008]

The present invention provides a laminated polyester film having an easy-adhesion layer provided on at least one side of a polyester film, wherein the easy-adhesion layer comprises a compound having a carboxyl group and / or a salt thereof. Acrylic resin 1 containing not less than 40% by weight but not more than 40% by weight of a copolymerized acrylic resin and a melamine-based cross-linking agent as main components
A laminated polyester film comprising 0.1 to 40 parts by weight of a melamine-based cross-linking agent with respect to 00 parts by weight, and a sublimation type ink layer provided on one side of the laminated polyester film. The sublimation type thermal transfer material is the main point.

The polyester of the polyester film of the present invention is a general term for polymers having an ester bond as a main bonding chain of the main chain, and preferable polyesters are as follows:
Main constituent is at least one constituent selected from ethylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4-dicarboxylate, and the like. What is made into an ingredient is mentioned. These constituent components may be used alone or in combination of two or more kinds, and among them, polyester having ethylene terephthalate as a main constituent component is particularly preferable in view of quality, economy and the like. In addition, in applications where heat acts on the base material such as recording image receiving sheets for electrophotography, heat-sensitive recording, various printing, etc., polyethylene excellent in heat resistance and rigidity is used.
2,6-naphthalate is more preferred.

Further, these polyesters further contain a part of other dicarboxylic acid components and diol components, preferably 2 parts.
0 mol% or less may be copolymerized.

Further, in this polyester, various known additives such as antioxidants, heat resistance stabilizers, weather resistance stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, etc. Agents, antistatic agents, nucleating agents and the like may be added to such an extent that their characteristics are not deteriorated.

The intrinsic viscosity of the above-mentioned polyester (25 ° C.
Measured in o-chlorophenol) of 0.40 to 1.2
0 dl / g is preferable, and more preferably 0.50 to 0.
Those in the range of 80 dl / g are suitable for the content of the present invention.

The polyester film using the above polyester is preferably biaxially oriented when the easily adhesive layer is provided. The biaxially oriented polyester film means an unstretched polyester sheet or film in the longitudinal direction and the width direction of 2.5 to 5 each.
It is drawn about twice and then heat-treated to complete the crystal orientation, and shows a biaxial orientation pattern by wide-angle X-ray diffraction.

The thickness of the polyester film is not particularly limited, but from the viewpoint of mechanical strength and thermal conductivity,
It is usually 1 to 30 μm, preferably 2 to 15 μm.

In terms of transportability, the polyester film preferably has a roughened surface to some extent.
The center line average roughness measured according to IS-B-0601-1976 (cutoff: 0.25 mm) is 0.05 to
Those having a surface state of 0.4 μm are preferable.

The acrylic resin which is a constituent of the easy-adhesion layer of the present invention contains a compound having a carboxyl group and / or a salt thereof in an amount of 3% by weight or more and 40% by weight or less, preferably 3% by weight or more and 30% by weight or less. It is desirable that the copolymerization is preferably 4% by weight or more and 25% by weight or less. If the copolymerization amount is less than this, the desired adhesion cannot be stably obtained, and if it exceeds this, the adhesion is deteriorated.

Examples of the compound having a carboxyl group and / or a salt thereof include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic anhydride, fumaric acid and / or salts thereof (ammonium salt, lithium salt, sodium salt, Potassium salt, amine salt, etc.) and the like.
Among them, acrylic acid, methacrylic acid, and maleic anhydride are preferable in terms of easy adhesion, and acrylic acid is particularly preferable.

Known monomers can be used as the monomer component constituting the acrylic resin. For example, alkyl acrylate, alkyl methacrylate (as the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group,
2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.), 2-hydroxyethyl acrylate, 2-
Hydroxy group-containing monomers such as hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide,
Amide group-containing monomers such as N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, and N-phenylacrylamide, N, N-diethylaminoethyl acrylate, N, N- Examples thereof include amino group-containing monomers such as diethylaminoethyl methacrylate, epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, and these are copolymerized using one kind or two or more kinds. Furthermore, they can be used in combination with other types of monomers.

Examples of other types of monomers include epoxy group-containing monomers such as allyl glycidyl ether, sulfonic acids such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.). Monomers containing groups or salts thereof, vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkyl itacon. Examples thereof include acid monoesters, vinylidene chloride, vinyl acetate and vinyl chloride.

Further, as the acrylic resin of the present invention, a modified polyester copolymer such as acrylic, urethane,
It is also possible to use a block copolymer modified with epoxy or the like, a graft copolymer or the like.

The molecular weight of the acrylic resin of the present invention is preferably 100,000 or more, and more preferably 300,000 or more from the viewpoint of adhesion.

Preferred acrylic resins have acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate and n-butyl acrylate as a basic skeleton, and further have 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide and glycidyl methacrylate. The thing copolymerized is mentioned.

In the present invention, when an easily adhesive layer is provided by a method of coating a polyester film before completion of crystal orientation and stretching and heat treatment to complete the crystal orientation, heat treatment at high temperature is possible. It is particularly preferable because a uniform and thin film easy-adhesion layer can be obtained. In the case of laminating the easy-adhesion layer by the above method, the acrylic resin is preferably soluble or emulsifiable in water, and is preferably suspended from the viewpoint of environmental pollution and explosion proof, and such an acrylic resin is a reactive emulsifier or an interface. Emulsion polymerization using activator, suspension polymerization, soap-free polymerization, monomer having hydrophilic group (acrylic acid,
It can be prepared by a known method such as copolymerization with methacrylic acid, acrylamide, vinylsulfonic acid and salts thereof.

In the present invention, an acrylic resin different from the acrylic resin may be used in combination with the above acrylic resin. For example, since the acrylic resin usually has a low glass transition point (Tg) of less than 50 ° C., an acrylic resin having a higher glass transition point (Tg), for example, a glass transition point (Tg) of 50 ° C. or higher, Preferable use of an acrylic resin having a temperature of 60 ° C. or higher together further improves the moisture-resistant adhesiveness. Further, the mixing ratio of these different acrylic resins is not particularly limited.

The melamine-based cross-linking agent, which is another constituent of the easy-adhesion layer of the present invention, is a conventionally known one and is not particularly limited. For example, as a functional group, an imino group, a methylol group, or a methoxymethyl group or butoxymethyl group is used. A group having an alkoxymethyl group such as a group in one molecule, and examples thereof include an imino group-type methylated melamine resin, a methylol group-type melamine resin, a methylol group-type methylated melamine resin, and a complete alkyl type methylated melamine resin. Among them, the methylolated melamine resin is the most preferable. Further, in order to accelerate the thermal curing of the melamine-based crosslinking agent, it is preferable to use an acidic catalyst such as p-toluenesulfonic acid.

In the present invention, 0.1 to 40 parts by weight of a melamine-based crosslinking agent is added to 100 parts by weight of an acrylic resin, preferably 0.2 to 30 parts by weight, more preferably 0.3. Part by weight to 20 parts by weight is desirable. If the amount of the melamine-based cross-linking agent is less than this, not only the desired adhesiveness cannot be obtained, but also the moisture-resistant adhesiveness is poor, and addition exceeding this adversely affects the adhesiveness.

In the easy-adhesion layer, known additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic lubricant, a pigment, etc. are added within a range that does not impair the effects of the present invention. Dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents and the like may be added.

In particular, those obtained by adding and blending inorganic particles into the coating composition of the present invention and biaxially stretching it are more preferable because they have improved slipperiness.

Typical examples of the inorganic particles to be added include silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate and the like. The inorganic particles preferably have an average particle size of 0.01 to 10 μm, more preferably 0.05 to 5 μm, and still more preferably 0.08 to 2 μm, and the compounding ratio to the solid content in the coating agent is not particularly limited, 0.05 to 8 by weight
It is preferably part by weight, more preferably 0.1 to 3 parts by weight.

The preferred method for laminating the easily adhesive layer is most preferably a method in which it is applied during the production process of the polyester film and stretched together with the base film. For example, a melt-extruded polyester film before crystal orientation is stretched in the longitudinal direction by about 2.5 to 5 times, the surface to be coated is subjected to corona discharge treatment, and the coating agent is continuously applied to the treated surface. The applied film is dried while passing through a zone that is heated stepwise and stretched in the width direction by about 2.5 to 5 times.
Further, it is obtained by a method of continuously introducing the material into a heating zone of 150 to 250 ° C. to complete the crystal orientation. The coating liquid used in this case is preferably an aqueous system from the viewpoint of environmental pollution and explosion proof.

The easy-adhesion layer provided by such a method has excellent adhesiveness to the sublimation-type ink layer formed thereon, and at the same time, has excellent reproducibility of color density during printing. Have.

The thickness of the coating film is not particularly limited, but is usually 0.03 to 5 μm, preferably 0.05 to 2 μm, and more preferably 0.07 to 0.5 μm. If the thickness of the easy-adhesion layer is too thick, the dye may migrate to the side of the easy-adhesion layer and the original color density may not be obtained, and if it is too thin, the adhesion may be poor.

The coating method on the substrate film is a known coating method, for example, reverse coating method, gravure coating method,
A rod coating method, a die coating method or the like can be used.

A stick prevention layer is provided on the surface of the polyester film opposite to the surface provided with the easy adhesion layer in order to prevent fusion (stick) between the polyester film and the thermal head. As the stick-preventing layer, known compounds such as silicone compounds, fluorine compounds and their modified products, copolymers, organic and inorganic lubricants can be used, but the following compositions have more remarkable effects. . That is, a coating film formed by a coating agent containing a mixture of a wax composition and an oily composition as a main component, the coating film thickness is thinner than the center line average roughness of the surface provided with the stick prevention layer,
When laminated so as to have a thickness of 0.005 μm or more, it has a remarkable effect of preventing sticking.

Furthermore, when 20 or more / 100 μm ² elongated projections having a longitudinal / widthwise ratio of 3 or more formed on the surface of the stick-preventing layer are present in an amount of at least 20/100 μm ² , excellent running is achieved during printing. It has the property. The stick preventing layer having such elongated surface protrusions can be more remarkably expressed by stretching in at least one direction after coating. That is, it is a method of applying the polyester film before crystal orientation to the surface opposite to the surface on which the sublimation type ink layer is provided, stretching after drying or while drying, and completing crystal orientation. Can be done at. According to this method, the easy-adhesion layer and the stick-prevention layer can be continuously applied in the film manufacturing process, which is more economically advantageous than the case of applying them separately.

In the above-mentioned stick prevention layer, known additives such as antioxidants, heat resistance stabilizers, weather resistance stabilizers, ultraviolet absorbers, organic lubricants, pigments, etc. are added within a range that does not impair the effects of the present invention. Dyes, organic or inorganic fine particles, antistatic agents, etc. may be blended, but chlorine and alkali metal-containing materials that can damage the thermal head, including the main components of the layer, to prevent damage to the thermal head It is desirable not to contain inorganic particles having properties.

The sublimation type ink layer provided on the easy-adhesion layer is
The material is not particularly limited, and known materials can be appropriately used.
For example, binder components for dispersing the dye include celluloses, polyvinyl alcohol and its partial acetalized products, polyamides, and the like, and sublimable dyes include various disperse dyes and basic dyes. The thickness of the sublimation type ink layer is not particularly limited, but is usually 0.5 to 15 μm, preferably 1 to 7 μm.

Next, the method for producing the laminated polyester film and the sublimation-type heat-sensitive transfer material of the present invention will be explained by taking a polyethylene terephthalate (hereinafter abbreviated as PET) film as an example of the substrate film, but it is naturally limited to this. Not a thing. PET pellets having an intrinsic viscosity of 0.63 dl / g containing so-called precipitated particles and inorganic particles (for example, silica particles having an average particle size of 1 μm) precipitated during the polymerization process are vacuum dried according to a conventional method, melt-extruded, and sheet-shaped melted. The surface temperature of the body is about 30 using the static electricity cast method.
The film is wrapped around a cast drum at ℃ and cooled and solidified to prepare an unstretched PET film. At least one surface of this film is subjected to corona discharge treatment in the air, and a coating agent for forming an easy-adhesion layer is applied to at least the treated surface. The coated film is guided to a drying zone heated to 90 to 140 ° C. while being gripped with a clip and stretched 2.5 to 5.0 times in the width direction after or while drying, and then 160 to 2
Heat treatment is carried out in a heat treatment zone of 40 ° C. for 1 to 10 seconds to complete the crystal orientation of the polyester film to obtain a laminated polyester film. If necessary during this heat treatment, 3
A relaxation treatment of up to 12% may be applied.

A sublimation type ink is applied to the easily adhesive layer side of the laminated polyester film thus obtained, and a stick prevention layer is provided on the opposite side, and the sublimation type thermal transfer material of the present invention is slit into a predetermined width. To get However, the stick preventing layer may be provided during the film forming process as in the case of the easily adhesive layer forming coating agent.

[0040]

[Characteristic Measuring Method and Effect Evaluation Method] The characteristic measuring method and effect evaluating method in the present invention are as follows.

(1) Sublimation Ink Adhesion-1 (Adhesion in Normal State) The following sublimation ink is applied using a bar coater so that the thickness after drying will be about 3 μm. 2 at 120 ° C after coating
After drying for 1 minute and leaving it at 25 ° C and 60% relative humidity for 24 hours, attach Scotch Mending Tape (Sumitomo 3M Co., Ltd.) on the sublimation type ink layer and press it firmly by hand, then 180 degrees Peel in the direction. The following 5 grades were evaluated according to the state of the sublimation type ink layer remaining on the transfer material side at this time. (⊚) and (∘) make good adhesion. (◎): 100% ink remaining on the release surface (○): 〃 80% or more remaining (△): 〃 50% or more remaining (x): 〃 less than 50% Remaining substance (XX): Peeling without resistance "Sublimation ink composition":-Disperse dye KST-B-136 (manufactured by Nippon Kayaku Co., Ltd.) 4 parts by weight-Ethyl hydroxyethyl cellulose 6 parts by weight -Methyl ethyl ketone 45 parts by weight-Toluene 45 parts by weight (2) Sublimation type ink adhesion-2 (moisture resistance adhesion-A) A sublimation type ink layer is formed in the same manner as in the above (1), and 35
After leaving for 100 hours at 75 ° C. and a relative humidity of 75% and taking out, after 5 minutes under normal conditions, the adhesion was evaluated by the same method as the above (1).

(3) Sublimation type ink adhesion-3 (moisture resistance adhesion-B) A sublimation type ink layer was formed in the same manner as in the above (1), and 40
After leaving for 100 hours at 90 ° C. and 90% relative humidity and taking out, after 5 minutes under normal conditions, the adhesion was evaluated by the same method as in the above (1).

(3) Presence or Absence of Over-Transfer A sublimation-type thermal transfer material prepared by further providing the stick preventing layer shown below in the above (1) was used as a sharp color video printer GZ-P11W type (manufactured by Sharp Corporation). Was used to perform a transfer test under standard conditions. The receiving paper attached to the printer was used, and the state of overtransfer was visually observed.

"Stick prevention layer forming coating" -amino-modified silicone / epoxy-modified silicone / ethanol /
A coating material mixed with isopropyl alcohol = 3/2/45/50 (weight ratio).

(4) Printing Characteristics of Thermal Transfer Material The printing characteristics of the sublimation type thermal transfer material prepared by further providing the stick prevention layer in the above (1) are the same as those of Sharp Color Video Printer GZ-P11W type (Sharp Corporation). The product was visually inspected for the printing condition and evaluated according to the following criteria.

⊚: Very good printing characteristics ○: Good printing characteristics Δ: Slightly poor ×: Remarkably poor (5) Glass transition point (Tg) Differential scanning calorimeter (PERKIN ELMER DSC-)
It was measured at a temperature rising rate of 20 ° C./min using a type 2 (manufactured by PERKINE LMER).

[0047]

EXAMPLES Next, the present invention will be explained based on examples, but the present invention is not necessarily limited to these.

Example 1 0.15% by weight of precipitated particles having a particle diameter of 0.5 to 1.5 μm (particles deposited in the polymerization step) and 0.2 of calcium carbonate particles having an average particle diameter of about 1.5 μm. PET pellets containing 100% by weight (intrinsic viscosity 0.63 dl / g) were sufficiently vacuum dried, then fed to an extruder and melted at 280 ° C.,
It was extruded in a sheet form from a T-shaped die, wound around a mirror-casting drum having a surface temperature of 30 ° C. by an electrostatically applied casting method, and cooled and solidified. This unstretched sheet is
The film was heated to 0 ° C. and stretched 3.5 times in the longitudinal direction to obtain a uniaxially stretched film. One surface of this film was subjected to corona discharge treatment in air, and the easily adhesive layer forming coating agent was applied to the treated surface. The coating thickness was set to 0.15 μm after completion of crystal orientation.

"Easy-adhesion layer-forming coating agent" -Aqueous coating agent prepared by mixing acrylic resin / melamine-based crosslinking agent = 100/3 (weight ratio).

A water-based acrylic resin coating obtained by copolymerizing methyl methacrylate / ethyl acrylate / acrylic acid / N-methylol acrylamide as an acrylic resin at a ratio of 53/40/5/2 (weight ratio).

A methylol melamine coating agent as a melamine-based crosslinking agent.

The coated uniaxially stretched film is held by a clip, introduced into a preheating zone heated to 110 ° C. to dry the water, and continuously stretched 4.5 times in the width direction in a heating zone of 130 ° C. Then, heat treatment was performed for 2 seconds in a heating zone of 225 ° C. to prepare a laminated PET film with crystal orientation completed. At this time, the thickness of the base film was 6 μm. The results are shown in Table 1.

Comparative Example 1 PE prepared in Example 1 with no coating agent for forming an easily adhesive layer
Laminate P as in Example 1 except that a T film was made
An ET film was created. The results are shown in Table 1.

Comparative Example 2 A laminated PET film was prepared in the same manner as in Example 1, except that the melamine-based cross-linking agent was not added as the coating agent for forming an easily adhesive layer. Table 2 shows the results.

Comparative Example 3 A laminated PET film was prepared in the same manner as in Example 1 except that acrylic resin was used as the coating agent for forming an easily adhesive layer without adding acrylic resin. Table 2 shows the results.

Example 2 With the coating material for forming an easily adhesive layer of Example 1, an acrylic resin was replaced with methyl methacrylate / ethyl acrylate / acrylic acid / N.
-A laminated PET film was prepared in the same manner as in Example 1 except that a water-based acrylic resin coating material copolymerized with methylol acrylamide = 50/40/8/2 (weight ratio) was used. The results are shown in Table 1.

Examples 3 to 6 and Comparative Examples 4 to 5 Examples of the easily adhesive layer forming coating composition of Example 2 except that the mixing ratio of acrylic resin / melamine type cross-linking agent was changed as shown in Table 1. A laminated PET film was prepared in the same manner as in 1. The results are shown in Tables 1 and 2.

Example 7 In the coating material for forming an easily adhesive layer of Example 1, an acrylic resin was replaced with methyl methacrylate / ethyl acrylate / acrylic acid / N.
-Methylol acrylamide = 45/30/20/5
A laminated PET film was prepared in the same manner as in Example 1 except that the water-based acrylic resin coating agent was copolymerized at (weight ratio). The results are shown in Table 1.

Example 8 In the coating agent for forming an easily adhesive layer of Example 1, the acrylic resin was changed to methyl methacrylate / n-butyl acrylate / acrylic acid / N-methylol acrylamide = 63/30/5/2.
A laminated PET film was prepared in the same manner as in Example 1 except that the water-based acrylic resin coating agent was copolymerized at (weight ratio). The results are shown in Table 1.

Comparative Example 6 In the coating agent for forming an easily adhesive layer of Example 1, an acrylic resin was replaced with methyl methacrylate / ethyl acrylate / acrylic acid / N.
-Methylol acrylamide = 30/18/50/2
A laminated PET film was prepared in the same manner as in Example 1 except that the water-based acrylic resin coating agent was copolymerized at (weight ratio). Table 2 shows the results.

Example 9 A uniaxially stretched film was prepared in the same manner as in Example 1. Both sides of this film were subjected to corona discharge treatment in the air, and one side was coated with the coating material for forming an easy-adhesion layer of Example 2 and the other side was coated with the following stick-preventive layer-forming coating solution to give a coating thickness of 0. 1
It was applied to have a thickness of μm.

"Stick prevention layer forming coating agent" -oxidizing wax / polyethylene wax / synthetic lubricating oil =
A water-based coating agent mixed at 60/35/5 (weight ratio).

The coated uniaxially stretched film is held by a clip, introduced into a preheating zone heated to 110 ° C. to dry the water, and continuously stretched 4.5 times in the width direction in a heating zone of 130 ° C. Then, heat treatment was performed for 2 seconds in a heating zone of 225 ° C. to prepare a double-sided laminated PET film having crystal orientation completed. The thickness of the base film at this time is 6μ
It was m. The results are shown in Table 1.

Example 10 A laminated PET film was prepared in the same manner as in Example 2 except that the substrate film in Example 2 was changed to polyethylene-2,6-naphthalate film. The results are shown in Table 1.

Example 11 A laminated PET film was prepared in the same manner as in Example 1 except that a different acrylic resin was added in addition to the acrylic resin of Example 1 as the coating agent for forming an easily adhesive layer of Example 1. . The adhesions 1, 2, and 3 were all (⊚), there was no overtransfer, and the printing characteristics were good.

"Easy-adhesion layer-forming coating agent" -Aqueous coating agent mixed with acrylic resin / different acrylic resin / melamine-based cross-linking agent = 80/20/3 (weight ratio).

A water-based acrylic resin coating obtained by copolymerizing methyl methacrylate / ethyl acrylate / acrylic acid / N-methylol acrylamide as an acrylic resin at a ratio of 53/40/5/2 (weight ratio).

As a different acrylic resin, a water-based acrylic resin having a Tg of 70 ° C. copolymerized with methyl methacrylate / ethyl acrylate / acrylic acid / N-methylol acrylamide = 76/20/2/2 (weight ratio) Coating agent-Methylol melamine coating agent as a melamine-based crosslinking agent.

[0069]

[Table 1]

[Table 2]

[0070]

INDUSTRIAL APPLICABILITY The laminated polyester film and the sublimation-type heat-sensitive transfer material produced according to the present invention have excellent adhesion to the sublimation-type ink layer, and the adhesion does not deteriorate under high temperature and high humidity. It won't happen.

Claims (5)

[Claims] 1. A laminated polyester film in which an easy-adhesion layer is provided on at least one side of a polyester film, wherein the easy-adhesion layer contains 3% by weight or more and 40% by weight or less of a compound having a carboxyl group and / or a salt thereof. A laminated polyester film comprising a polymerized acrylic resin and a melamine-based cross-linking agent as main constituents, and 0.1 to 40 parts by weight of the melamine-based cross-linking agent per 100 parts by weight of the acrylic resin. . 2. The easy-adhesion layer further has a glass transition point (Tg).
Contains an acrylic resin having a temperature of 50 ° C. or higher, and the laminated polyester film according to claim 1. 3. The laminated polyester film according to claim 1, wherein the polyester film is a polyethylene terephthalate film or a polyethylene-2,6-naphthalate film. 4. A laminate obtained by applying an easy-adhesion layer-forming coating agent on at least one side of a polyester film before completion of crystal orientation when providing the easy-adhesion layer, and then stretching in at least one direction to complete crystal orientation. Polyester film,
The laminated polyester film according to any one of claims 1 to 3, further comprising an anti-stick layer provided on the opposite surface. 5. A sublimation-type heat-sensitive transfer material, wherein a sublimation-type ink layer is provided on one surface of the laminated polyester film according to any one of claims 1 to 4.