JP2005036237A - Polyester resin for sublimation transfer image receptor protection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film for sublimation transfer image receptor which film improves the image preservability while it retains images with high sensitivity and high quality for a long period of time. <P>SOLUTION: This polyester resin for sublimation transfer image receptor protection film is obtained by copolymerizing a monomer having an alicyclic structure with not less than 15 mol% of an acid component and/or a glycol component. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a film used for protecting an image of a sublimation transfer image receptor used in combination with a thermal transfer sheet containing a sublimation dye, a method for protecting an image using the film, and image protection for the film. It relates to a sublimation transfer image receptor protected by a layer.

  The sublimation type thermal transfer method is a method of obtaining a printed image by transferring a sublimation dye onto a sublimation transfer image receiving member in contact with the thermal transfer sheet by heating a thermal transfer sheet coated with a sublimation dye with a thermal head or the like. .

  As the dyeing resin used in the dyeing layer of the sublimation transfer image receptor, those containing saturated polyester as a main component have been conventionally used as disclosed in Patent Documents 1 to 4 and the like. Patent Document 5 describes what is characterized by multilayer lamination.

  Conventionally, when a saturated polyester is used as a dyeing layer resin, a high-quality image with good color density, gradation, and color reproducibility can be obtained. On the other hand, the recorded image is closely related to the storage state of the dye, and due to the study of the resin design for the dyeing layer, there is a point that does not reach the image storage stability of silver salt color photographs, but considerable storage stability is obtained. Has reached a level that can be. However, when compared with a silver salt color photograph, this method in which the dye image-receiving layer is exposed to the surface has a fundamental problem that the image is disturbed after long-term storage.

  As an example of improving the problem, there is a resin using a dyeing layer resin that places importance on preservability, but in this case, there are disadvantages such as low dyeing sensitivity and slow printing speed. In addition, the conventional multilayer laminate is intended to provide a thin and correct solution for preventing thermal fusion caused by heating of the thermal head, and cannot improve the storage stability.

On the other hand, after dyeing, a method is proposed in which a film having a transparent or translucent heat-sealing layer is superimposed on a sublimation transfer image receptor, and the heat-sealing layer is fused to the dyeing layer, thereby protecting the image. (Patent Documents 6 to 9). However, even with these methods, the image storage stability was insufficient.
JP-A-57-107885 JP-A-60-64899 JP 61-258790 A JP 62-105689 A JP-A-3-136896 JP-A-1-237193 JP-A-3-70637 Japanese Patent Laid-Open No. 4-15118 JP-A-4-52223

  An object of the present invention is to provide a film for a sublimation transfer image receptor that solves the above-described problems and improves image storage stability while maintaining high-sensitivity and high-quality images for a long period of time.

  Another object of the present invention is to provide a method for protecting an image of a sublimation transfer image receptor using the above film.

  Another object of the present invention is to provide a sublimation transfer image receptor protected by the image protective layer of the film.

  As a result of intensive studies to achieve the above object, the present inventors have found that a resin having a glass transition temperature of 68 ° C. or higher and / or a main chain as a layer for protecting an image of a sublimation transfer image receptor. The inventors have found that it is particularly useful to use a polyester resin having an alicyclic skeleton, and have reached the present invention. That is, the present invention relates to a protective film for a sublimation transfer image receptor in which an image protection layer used for image protection of a sublimation transfer image receiver is formed on a heat resistant substrate, and the glass transition temperature of the image protection layer is 68 ° C. or higher. A protective film for a sublimation transfer image receiver, comprising at least one of the resin (a) or the resin (b) having an alicyclic structure in the resin skeleton.

  In the present invention, at least one of the resin (a) and the resin (b) can be a resin selected from a polyester resin, a polyurethane resin, a polyamide resin, an epoxy resin, and an acrylic resin.

  Further, the sublimation characterized in that the image protective layer surface of the protective film for sublimation transfer image receiver described above is superimposed on the dye layer surface of the sublimation transfer image receiver, and the image protective layer is fused on the dye layer by heating. An image protection method for a transfer image receptor.

  Furthermore, in the sublimation transfer image receiver provided with the base material, the dyeing layer provided on the base material, and the image protective layer, the resin (a) having a glass transition temperature of 68 ° C. or higher is applied to the image protective layer, or And a sublimation transfer image receiver characterized in that the resin skeleton contains at least one resin (b) having an alicyclic structure.

  The image protective layer used in the present invention has an excellent image protection property of maintaining a high-sensitivity, high-quality image for a long time, and the sublimation type thermal recording paper having this image protective layer is industrially useful. It is.

  In the present invention, the sublimation transfer image receptor refers to a recording material from which an image can be obtained by transferring a sublimation dye to a dyeing layer. The dyeing layer is a layer on which a sublimation dye is transferred to form an image, and the image protection layer is a dyeing layer for the purpose of protecting the image obtained in the dyeing layer from contamination, light, and the like. A transparent or translucent layer provided on the top.

  As the resin for forming the image protective layer of the sublimation transfer image receptor in the present invention, at least the resin (a) having a glass transition temperature (Tg) of 68 ° C. or higher or the resin (b) having an alicyclic structure in the resin skeleton is used. One is used.

  The resin (a) has a Tg of preferably 70 ° C. or higher, particularly preferably 73 ° C. or higher. In the case of the resin (b), Tg is preferably 30 ° C. or higher, and more preferably 40 ° C. or higher. When the temperature is lower than 30 ° C., the film is severely blocked, which is not preferable for practical use as an image receiving paper. Further, since the heat resistance is inferior, the image storability is not exhibited well. Although the upper limit of Tg is not specifically limited, 100 degrees C or less is preferable from the point of the brittleness of a protective layer, and 85 degrees C or less is especially preferable.

  The number of carbon atoms of the monomer constituting the alicyclic skeleton in the resin (b) is 3 to 20, preferably 6 to 16. Examples of the alicyclic skeleton include saturated alicyclic skeletons such as cycloparaffin, and those containing an unsaturated bond in the ring such as cycloalkene and cycloalkyne. Examples thereof include polycyclic ones such as cyclic and tricyclic. Specific examples include cyclohexane, cyclodecane, decalin, hydrogenated bisphenol A, tricyclodecane and the like.

  The proportion of the alicyclic skeleton in the resin (b) is preferably 15 mol% or more, more preferably 30 mol% or more. The type of the resin (a) and the resin (b) is not particularly limited, but a polyester resin, a polyurethane resin, a polyamide resin, an epoxy resin, and an acrylic resin are preferable, and among them, a polyester resin, a polyurethane resin, and a polyamide resin are particularly preferable. A polyurethane resin is preferred. When a polyester resin is used as the resin (b), it is preferably a polyester resin obtained by copolymerizing a monomer having an alicyclic skeleton with a dicarboxylic acid component and / or a diol component.

  It is preferable to contain 15 mol% or more as an acid component and / or glycol component as a component in the polyester of the monomer which has an alicyclic skeleton in this invention, and it is more preferable to contain 30 mol% or more.

  Examples of the alicyclic dicarboxylic acid that can be used in the present invention include cyclohexane dicarboxylic acid, tricyclodecane dicarboxylic acid, decalin dicarboxylic acid, and the like. These compounds may be methyl esterified, and those acids may be used. It may be an anhydride.

  Examples of the diol component having an alicyclic skeleton include tricyclodecanediol, tricyclodecane dimethylol, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol A ethylene oxide, and propylene oxide adducts. Can be mentioned. These may be used alone or as a mixture.

  Other components that can be used to obtain the polyester resin of the present invention include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, diphenic acid, sulfoterephthalic acid as aromatic dicarboxylic acid, 5 -Aromatic dicarboxylic acids such as sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5- (4-sulfophenoxy) -isophthalic acid, sulfoterephthalic acid, their metal salts, Aromatic oxycarboxylic acids such as ammonium salt, p-oxybenzoic acid, p- (hydroxyethoxy) benzoic acid and the like can be mentioned. Examples of aliphatic dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, Examples include dodecanedioic acid and dimer acid.

  Examples of unsaturated dicarboxylic acids include fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid and the like. Tri- and tetracarboxylic acids such as trimellitic acid and pyromellitic acid can also be mentioned.

  On the other hand, the glycol component includes aliphatic glycols such as ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6- Hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, hydroxypivalic acid neopentyl glycol ester, dimethylolheptane, 2,2,4-trimethyl -1,3-pentanediol and the like.

  Diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol ethylene oxide adduct, neopentyl glycol propylene oxide adduct may be used as necessary as the ether bond-containing glycol. sell.

  As aromatic-containing glycols, para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, bisphenol A, ethylene oxide adduct of bisphenol A and propylene Examples thereof include glycols obtained by adding 1 to several moles of ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols such as oxide adducts.

The polyurethane resin is composed of a polyol, an organic diisocyanate compound, and, if necessary, a chain extender having an active hydrogen group, a molecular weight of 500 to 100,000, and a urethane bond content of 500 to 4000 equivalents / 10 ⁶ g. The thing which becomes.

  Specific examples of the polyol include polyester polyol, polyether polyol, polycarbonate polyol, and polyacrylate polyol. The alicyclic structure may be contained in either a polyol or a chain extender.

  The polyester polyol is produced by using the compounds already exemplified in the section of the polyester resin as the dicarboxylic acid component and the glycol component, and it is desirable that both terminal groups or side chains are hydroxyl groups and the molecular weight is 500 to 10,000. .

  Examples of the organic diisocyanate compound include hexamethylene diisocyanate, tetramethylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 1,3-diisocyanate methylcyclohexane, 4 , 4′-diisocyanate dicyclohexane, 4,4′-diisocyanatocyclohexylmethane, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, 2 , 4-Naphthalene diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, 4,4′-di Socia sulfonate ether, 1,5-naphthalene diisocyanate, and the like.

  Examples of the chain extender having an active hydrogen group used as necessary include ethylene glycol, propylene glycol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, diethylene glycol, spiroglycol, polyethylene glycol and the like. Examples include amines such as glycols, hexamethylenediamine, propylenediamine, and hexamethylenediamine.

  The polyurethane resin is produced by a known method in a solvent at a reaction temperature of 20 to 150 ° C. in the presence of a catalyst or without a catalyst. As the solvent used in this case, for example, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, and esters such as ethyl acetate and butyl acetate can be used. As the catalyst for promoting the reaction, amines, organotin compounds and the like are used.

  The reduced viscosity of the resin (a) and / or (b) used in the image protective layer of the present invention is preferably 0.05 to 1.5 dl / g, more preferably 0.10 to 1.3 dl / g. It is. When the reduced viscosity is less than 0.05 dl / g, the strength as a coating film required for the image protective layer is lowered. On the other hand, if it exceeds 1.5 dl / g, the solution viscosity at the time of coating on the substrate becomes too high and handling becomes difficult.

  For the purpose of further improving the protective properties, the resin (a) and / or (b) used in the image protective layer of the present invention may be thermoset or crosslinked. Examples of the curing agent in the case of thermosetting include silicone resin, melamine resin, phenol-formalin resin, epoxy resin, and isocyanate resin. Examples of the crosslinking include ionic crosslinking and radiation crosslinking.

  In addition to the resin (a) and / or (b) used in the image protective layer, other resins can be used in combination. The resins that can be used in combination include polyvinyl resins, polycarbonate resins, polyacrylic resins, polyester resins, polymethacrylate resins, polyolefin resins, cellulose derivative resins, polyether resins, vinyl chloride resins, polyurethane resins, polyamide resins, epoxy resins, polyacetal resins. , Polystyrene resins and modified resins thereof.

  Furthermore, oil mineral powders and organic powders such as paraffin wax, microcrystalline wax, carnauba wax, beeswax, chlorinated paraffin petroleum resin, low molecular polyethylene, linseed oil and mineral oil may be added.

  The resin (a) and / or the resin (b) is preferably at least 1 wt% or more, more preferably 5 to 100 wt% in the resin forming the image protective layer.

  The thickness of the image protective layer is not particularly limited, but is usually about 0.01 to 20 μm.

  The type of the substrate for the sublimation transfer image receptor protecting film is not particularly limited as long as it has heat resistance, but paper, synthetic paper, various films, various sheets, and the like can be used. Examples thereof include plastic films such as polyester, polycarbonate, polyarylate polyethersulfone, polyimide, polyamide, polyamideimide, polyfluoroethylene, and synthetic papers thereof, and these may be laminated. Moreover, a base material is about 5-100 micrometers, Preferably it is 8-50 micrometers.

  Resin (a) and / or resin (b) and other components added as necessary to produce a film for protecting a sublimation transfer image receptor by coating a resin that forms an image protective layer on a heat resistant substrate These resins, additives and the like can be dissolved in a solvent for coating, or can be coated in the form of a non-aqueous dispersion, an aqueous dispersion or an aqueous solution (no solvent). It is customary to use the solution or dispersion having a solid concentration of about 1 to 70% by weight when coating on a substrate.

  In the sublimation transfer image receptor protecting film of the present invention, a release layer containing a silicone resin, a fluorine resin, a wax, or the like may be provided between the heat resistant substrate and the image protective layer.

  An adhesive layer for the purpose of improving the adhesiveness with the image receiving layer may be provided on the image protective layer. Further, a heat-resistant back coat layer containing a thermosetting or photo-curing resin or the like may be provided on the substrate opposite to the surface on which the image protection layer is formed. As the release layer, the adhesive layer, and the heat-resistant back coat layer, those used for hot melt transfer ink ribbons and sheets, sublimation type heat transfer ink ribbons and sheets can be used as examples.

  The dyeing resin used for the image-receiving paper of the sublimation transfer image receiver is not particularly limited, but polyvinyl resin, polycarbonate resin, polyacrylic resin, polyester resin, polymethacrylate resin, polyolefin resin, cellulose resin, polyether resin, Vinyl chloride resin and its modified resin can be used singly or in combination.

  For the purpose of improving the light fastness of recorded images, the image receptor has an ultraviolet absorber such as hydroxybenzophenone and dihydroxybenzophenone, a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylic acid derivative ultraviolet absorber, and an antioxidant. An agent or the like can be blended. These agents may be added to either the image protective layer or the image receiving layer, or both layers may be added.

  Although it does not specifically limit as a base material used for a sublimation transfer image receiver, Paper, a synthetic paper, various films, various sheets, a metal plate, a glass plate, cloth, a nonwoven fabric etc. are mentioned.

  The film for protecting a sublimation transfer image receptor of the present invention comprises a resin (a) and / or a resin (b) in which a part of a dye layer of a thermal transfer sheet coated with a yellow, cyan, magenta, or black sublimation dye is applied. May be used by being incorporated in a part of the thermal transfer sheet in the form of being replaced with an image protective layer containing at least one of the above, or a single sublimation transfer image receptor protecting film.

  The image protection layer of the sublimation transfer image receptor protecting film of the present invention is overlaid on the dyeing layer of the sublimation dye image receptor and heated with a heating head, heat ray irradiation such as laser light, etc. The protective layer is fused.

  The sublimation dye image receptor thus obtained has a layer containing a specific resin (a) and / or resin (b) laminated on the dyeing layer.

  Hereinafter, the present invention will be described using examples. The present invention is not particularly limited by the examples. In the examples, “part” simply means “part by weight”, and “%” means “% by weight”. Each measurement item was performed according to the following method.

(1) Reduced viscosity 0.01 g of polyester resin was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4) and measured at 30 ° C.

(2) Glass transition temperature (Tg)
It measured with the temperature increase rate of 20 degree-C / min using the differential scanning calorimeter (DSC). The sample was used by crimping 5 mg of the sample in an aluminum holding lid type container.

(3) Printed image density evaluation method The sublimation transfer image receptor and the thermal transfer sheet are overlapped so that the dyeing layer and the dye layer are in contact with each other, and the head output is 0.7 W / dot from the substrate side of the thermal transfer sheet by the thermal head. Then, heating was performed at a head heating time of 8 mS and a dot density of 3 dots / mm, and the cyan dye in the color material layer was transferred to the dyeing layer. The obtained transferred image density was measured with a reflection densitometer (Dainippon Screen, DM-600).

(4) Evaluation method of heat resistance (dark fading rate) The image density of the image receptor to which a cyan dye was transferred was measured. The image density after standing (aging) for 168 hours in an environment of 60 ° C. in a dark place was measured and indicated by dye retention (%) in comparison with the density before the heat resistance test.

(5) Evaluation method of light resistance The image receiving sheet on which the cyan dye was transferred was irradiated so that the energy given by the xenon lamp was 67.0 KJ / m ² under the condition of 40 ° C., before the light resistance test. The dye density retention rate (%) in comparison with the density is shown.

(6) Plasticizer resistance test method 1 cm ² of a 50 μm-thick vinyl chloride film was adhered to the surface of the image receptor onto which the cyan dye had been transferred, and a load of 5 g was applied on the vinyl chloride film. The sample was allowed to stand for 24 hours in an environment of ° C., and the color loss of the cyan dye and the trace of the film were observed. After aging, ○ indicates that there is no film trace on the surface of the image-receiving layer, ○ indicates that there is no change in color, △ indicates that there is no change in color but film mark remains, and X indicates that the color also changes and film trace remains. did.

(7) Fingerprint resistance test method Strongly press the thumb against the surface of the image receptor to which the cyan dye has been transferred so that the fingerprint remains on the image surface, and leave it in an environment of 40 ° C. for 48 hours. I saw agglomeration, color loss, and fingerprint marks. After aging, ○ indicates that there is no fingerprint trace on the surface of the image receiving layer, no change in color, etc., △ indicates that there is no change in color but fingerprint trace remains, and × indicates that the color also changes and fingerprint trace remains. did.

(Production example of polyester resin for image protective layer)
In a stainless steel autoclave equipped with a stirrer, thermometer and partial reflux condenser, 291 parts of dimethyl terephthalate, 291 parts of dimethyl isophthalate, 100 parts of 1,4-cyclohexanedimethanol, 229 parts of ethylene glycol, and tetra-n- Charge 0.5 parts of butyl titanate, conduct transesterification to 160-220 ° C. over 4 hours, then raise the temperature of the reaction system to 255 ° C., gradually depressurize the reaction system, and then reduce the pressure to 0.2 mmHg. For 1 hour and 30 minutes to obtain polyester resin A. The obtained polyester A was light yellow and transparent, the reduced viscosity was 0.45, and the Tg was 70 ° C. Table 1 shows polyester resins B to E obtained by the same production method.

(Application example of image protective layer)
The obtained polyester resin A was diluted with a mixed solution of methyl ethyl ketone: tetrahydrofuran = 1: 1 to obtain a 5% solution. This solution was applied to a 5 μm thick transparent PET film (manufactured by Toyobo Co., Ltd.), to which a silicone release agent had been applied in advance, using a wire bar so as to obtain a 1.5 μm dry coating film, thereby obtaining an image protective layer. It was. The evaluation results of the above (1) to (7) are shown in Table 2.

(Example 1)
Byron 200 (manufactured by Toyobo Co., Ltd.) as a dyeing layer resin was diluted with a mixed solvent of methyl ethyl ketone: toluene = 1: 1 to give a 20% solution. Epoxy-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd .: KF-102) is added to this solution in an amount of 10% by weight with respect to the resin component, and a wire bar is used on a synthetic paper having a thickness of 150 μm (manufactured by Oji Yuka: Yupo PPG-150). It was applied so that a dry coating film of 4 μm was obtained. The sheet was dried in an atmosphere at 120 ° C. for 30 minutes to obtain a dyed layer (dye receiving layer).

  After the dye was transferred to the obtained dyed layer by the method described above, the image protective layer applied to the transparent PET film was subjected to a head output of 0.7 W / dot, a head heating time of 8 mS, and a dot density by a thermal head. It was heated at 3 dots / mm and transferred onto the dyeing layer. The adhesion between the obtained image protective layer and the dyed layer was very good.

(Examples 2-3)
Using polyester resins B to C, a dyeing layer was provided in the same manner as in Example 1 to give Examples 2 to 3, respectively.

(Comparative Example 1)
Using polyester resin D, a dyeing layer was provided in the same manner as in Example 1 to obtain Comparative Example 1.

(Comparative Example 2)
Using polyester resin E, a dyeing layer was provided in the same manner as in Example 1 to obtain Comparative Example 2.

(Comparative Example 3)
A dyed layer was provided in the same manner as in Example 1, and evaluation was performed without transferring the image protective layer.

Claims (2)

  A polyester resin for a sublimation transfer image receptor protective film obtained by copolymerizing a monomer having an alicyclic skeleton with 15 mol% or more of an acid component and / or a glycol component.   The polyester resin for a sublimation transfer image receptor protective film according to claim 1, having a glass transition temperature of 68 ° C or higher.