JP2008012903A - Sublimation transfer image-receiving sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein dyeing functionalities and resistance to ultraviolet light are deteriorated while the generation of an abnormal noise and the occurrence of sticking in printing can be prevented, in a conventional sublimation transfer image-receiving sheet. <P>SOLUTION: In the sublimation transfer image-receiving sheet in which a reception layer and the like are provided on a base material, at least a compound expressed by the specific chemical structural formula is contained as an ultraviolet absorber in the reception layer and the like. This brings about the sublimation transfer image-receiving sheet with the proper dyeing properties and resistance to the ultraviolet light, whit the sheet prevents the generation of the abnormal noise and the occurrence of the sticking in separation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sublimation transfer image receiving sheet that is used while being superposed on a sublimation transfer sheet. Specifically, the present invention relates to a sublimation transfer image receiving sheet having good light resistance and good image color.

  In recent years, a so-called sublimation transfer recording system is attracting attention as a kind of full-color printing system because of its features such as fidelity of color tone reproduction and high image quality. This method uses a sublimation transfer sheet (hereinafter referred to as a transfer sheet) formed by applying a sublimation dye on a substrate, and a thermal head having a heating element that selectively applies a voltage according to a recording signal. With respect to a sublimation transfer image receiving sheet (hereinafter referred to as an image receiving sheet) in which a layer having dyeability (hereinafter referred to as a receiving layer) having a dyeing property with respect to the dye is provided on another substrate, the thermal head is disposed via the transfer sheet. In addition to pressure contact, a voltage is applied to the heat generating element based on recording information, so that the dye is transferred and fixed (transferred) to the receiving layer of the image receiving sheet by adhesion, adsorption, dyeing, etc., and a desired recorded image is obtained. It is a recording method to obtain.

  Since the receiving layer of the image receiving sheet used in this sublimation transfer recording system needs to receive and dye the dye sublimated from the transfer sheet, it is generally composed mainly of a resin having high affinity for the dye. Yes.

  As a prior art relating to a resin constituting such a receiving layer, Patent Document 1 discloses that a polyester resin, a polycarbonate resin, a polyvinyl butyral resin, an acrylic resin, a cellulose resin, a polystyrene resin, or the like is used. However, if the receiving layer is made of a resin selected from these resins in consideration of improvement in dye dyeing property and improvement in image storage stability such as light resistance, particularly at high temperatures and high humidity, When printing in a low-temperature, low-humidity environment, abnormal noise occurs when the transfer sheet and the image-receiving sheet are peeled off. In extreme cases, the transfer sheet and the image-receiving sheet cannot be separated while being adhered to each other ( Etc.) has occurred.

  Here, since dye dyeing property and releasability at the time of printing are in a trade-off relationship, various additives have been conventionally added to the resin for the receiving layer, or for the receiving layer, in order to improve both properties. A plurality of resins are mixed and used as the resin, but those having desired characteristics have not been obtained yet.

  For example, as a method for improving the resin for the receiving layer, there has been proposed a method in which isocyanate is added to a polyester resin or the like, and the receiving layer-constituting resin is three-dimensionally cross-linked by a reaction between them (Patent Document 2). However, when three-dimensional cross-linking is performed by simply adding isocyanate as described in Patent Document 2 and the like, although there is an improvement in the generation of abnormal noise and sticking, it is dyeable and light resistant to ultraviolet rays and the like. As a result, there was a problem in practical use.

  In general, various light absorber compounds such as benzotriazole, benzophenone, phenyl salicylate, and cyanoacrylate are added to an image receiving sheet for the purpose of improving light resistance, particularly ultraviolet light resistance (for example, patent documents). 3). In Patent Document 3 and the like, there is a description regarding the point that these compounds absorb ultraviolet rays and improve light resistance, but any knowledge is described from the viewpoint of solving the problem of occurrence of abnormal noise and sticking described above. Not.

JP 60-25793 A JP-A-6-305268 Japanese Patent Laid-Open No. 11-180050

  The present invention has been made in order to solve the problems of such a conventional configuration, and has good dye dyeing properties and light resistance, and generates abnormal noise and sticking during peeling. An object of the present invention is to provide a sublimation transfer image receiving sheet that can be prevented.

下記式（２）：

および下記式（３）：

で表される化合物の少なくとも一種を含有させたものである。 And the 1st viewpoint of this invention is a sublimation transfer image receiving sheet which provides a receiving layer on a base material in order to achieve the said objective, WHEREIN: In a receiving layer, following formula (1):

Following formula (2):

And the following formula (3):

It contains at least one compound represented by the formula:

  In the present invention, it is preferable that the receiving layer further contains at least one selected from a fluorescent brightener, titanium oxide, zinc oxide, and cerium oxide.

  Further, an intermediate layer is further provided between the substrate and the receiving layer, and the intermediate layer is a compound represented by the above formulas (1) to (3), a fluorescent brightener, titanium oxide, zinc oxide, and It preferably contains at least one selected from cerium oxide.

  Furthermore, in order to achieve the above object, the second aspect of the present invention is a sublimation transfer image-receiving sheet in which a receiving layer is provided on a substrate via an intermediate layer. It contains at least one compound represented by 3).

  In the present invention, the intermediate layer preferably further contains at least one selected from a fluorescent brightener, titanium oxide, zinc oxide, and cerium oxide.

  The receiving layer preferably contains at least one selected from a fluorescent brightener, titanium oxide, zinc oxide, and cerium oxide.

  According to the present invention, the above-described conventional trade-off problem is solved, and sublimation capable of effectively preventing the generation of abnormal noise and sticking at the time of peeling while having good dye dyeing properties and light resistance. A transfer image receiving sheet can be provided.

  The present inventor conducted intensive research to solve the above-described problems of the prior art, and the reason is not yet clear, but the receiving layer of the image receiving sheet is configured using the above specific compound as an ultraviolet absorber. By including it in a binder resin, etc., it is possible to prevent the generation of abnormal noise and sticking at the time of peeling during thermal transfer without curing the binder resin with, for example, isocyanate, etc. The present invention has been completed by finding that it can be effectively improved.

  Examples of the substrate (support) used in the sublimation transfer image-receiving sheet of the present invention include paper substrates such as art paper, coated paper, cast coated paper, cellulose fiber paper, and high-quality paper, and one or both sides of these paper substrates. A composite paper obtained by laminating a resin film can be used. As the film substrate, films such as polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyester, polystyrene, polycarbonate, nylon and the like can be suitably used. Further, as these films, a film having a multilayer structure, at least one layer of which is mainly composed of a resin and an inorganic pigment, and a film having a multilayer structure composed of a biaxially stretched foam layer having voids is more preferable. Can be used. In addition, a base material is not limited to what was mentioned above, For example, a transparent polyester sheet can be used as a support body, and it is also possible to provide the image receiving sheet which concerns on this invention as an image receiving sheet for OHP.

  Moreover, it is preferable that the thickness of this base material exists in the range of 80 micrometers-300 micrometers, and it is more preferable that it exists in the range of 200 micrometers-250 micrometers. When the thickness of the substrate is less than 200 μm, particularly less than 80 μm, the elasticity in the thickness direction is inevitably reduced when the rigidity required for the support is obtained, and the print density tends to be lowered. On the other hand, a thickness exceeding 250 μm, particularly 300 μm, is excessively large and uneconomical than necessary.

  Furthermore, examples of the binder resin for forming the receiving layer provided on the substrate include polyolefin resins such as polyethylene and polypropylene, vinyl halide resins such as polyvinyl chloride, polyvinyl acetate, and polyacrylic esters. Vinyl resins, polyethylene resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymers of olefins such as ethylene and propylene and other vinyl monomers, polycarbonate, etc. The synthetic resin which can be obtained is mentioned, but it is not limited to these.

  In addition, an intermediate layer such as a primer layer and an ultraviolet absorbing layer, a barrier layer for preventing migration of dye dyed on the receiving layer, and the like are provided between the base material and the receiving layer as necessary. Also good. Moreover, you may provide suitably the back surface intermediate layer which has a desired function, the back layer which has various functions, such as writing property and lubricity, etc. in the surface on the opposite side to the receiving layer of a base material. Here, examples of the binder resin for forming the intermediate layer and the like include the same resins as those described above as the binder resin for forming the receiving layer.

  In addition, these resins further include antioxidants, ultraviolet absorbers other than the above-described ultraviolet absorbers, light stabilizers, coumarin-based, stilbene-based, and thiophene-based materials as long as they do not depart from the purpose of the present invention. Or a fluorescent whitening agent, or a pigment or filler such as titanium oxide, zinc oxide, cerium oxide, kaolin clay, or calcium carbonate.

In particular, in the present invention, the aspect in which the fluorescent whitening agent is added to the receiving layer has the following effects.
That is, the absorption wavelength of the above-mentioned coumarin, stilbene, thiophene and other fluorescent brighteners generally has a maximum absorption around 375 nm, and the function of converting the absorbed energy into fluorescence around a wavelength of 420 nm. have. However, when conventional ultraviolet absorbers such as the above-described benzotriazole are added, there is a tendency that the whitening effect of the fluorescent whitening agent is hindered by overlapping the fluorescent whitening agent and the absorption wavelength.
On the other hand, since each ultraviolet absorbing compound used in the present invention does not have an absorption peak near 375 nm, the ultraviolet absorbing effect can be sufficiently exerted without inhibiting the whitening effect of the conventional fluorescent whitening agent.

  Further, such an effect of the present invention can be obtained not only in the aspect in which the fluorescent whitening agent is added to the receiving layer but also in the aspect in which the fluorescent whitening agent is added to the intermediate layer.

Furthermore, in the present invention, the aspect in which a filler such as titanium oxide, zinc oxide, cerium oxide or the like and an ultraviolet absorber are added to the receiving layer has the following effects.
That is, when a conventional ultraviolet absorber such as benzotriazole is added, significant yellowing occurs in the presence of metal ions such as titanium ions. In each ultraviolet absorbing compound used in the present invention, titanium ions and the like Even in the presence of metal ions, yellowing does not occur. Such an effect can be obtained not only in the receiving layer but also in an embodiment in which titanium oxide or the like is added to the intermediate layer in contact with the receiving layer.

  Furthermore, the ultraviolet absorbing compound used in the present invention can be added not only to the receiving layer but also to the intermediate layer, and in this case, the same effect as when added to the receiving layer can be obtained.

The formation of the receiving layer, intermediate layer, etc. is a gravure printing method in which a solution obtained by adding the necessary additives to the above-mentioned binder resin is dissolved in an appropriate organic solvent, or a dispersion liquid is dispersed in an appropriate organic solvent or water. It can be carried out by applying and drying on a base material or an intermediate layer provided on the base material by a known coating means such as a screen printing method or a reverse roll coating method.
Although there is no restriction | limiting in particular in the thickness of a receiving layer, Generally, they are 1 micrometer-10 micrometers.

  In order to improve the film forming property of the binder resin, isocyanates may be added to the resin and cured. However, if the degree of curing is set too high, the effect of the present invention cannot be exhibited sufficiently. There is. Therefore, it is preferable to keep the equivalent ratio of the functional group in the binder resin to the NCO group of the isocyanate to be added to about 1: 0.5.

In the present invention, any one of the compounds represented by the above formulas (1), (2) and (3) is contained in the binder resin constituting the receiving layer or intermediate layer of the image receiving sheet, so that the heat transfer can be performed. Occurrence of abnormal noise and sticking at the time of peeling can be prevented, and dye dyeing property and light resistance can be effectively improved. Moreover, in this invention, the same effect can be acquired also by making 2 or more types of these compounds contain together in binder resin. In that case, the amount added to the receiving layer or intermediate layer when each compound is used alone or the total amount added to the receiving layer or intermediate layer when using each compound in combination is the total solid content of the receiving layer or intermediate layer. Is 100 parts by mass, preferably 0.1 parts by mass to 30 parts by mass, more preferably 5 parts by mass to 20 parts by mass.
When the addition amount is less than 0.1 parts by mass with respect to 100 parts by mass, it does not contribute to the prevention of abnormal noise and sticking, and the improvement in light resistance, which is the original purpose of adding the UV absorber, is seen. There is a tendency not to be. Moreover, when the addition amount exceeds 30 parts by mass with respect to 100 parts by mass, not only the effects such as prevention of abnormal noise and sticking, improvement of dyeing property / light resistance, etc. are exhibited, but the UV absorber is bleed. As a result, the printed image tends to blur.

  Hereinafter, the present invention will be described in further detail with reference to Examples and Comparative Examples, but the present invention is not limited to these.

(Examples 1-21) and (Comparative Examples 1-3)
(Production of image receiving sheet)
On a commercially available A-2 coated paper (Mitsubishi Paper Co., Ltd .; thickness: 165 μm) as a base material, an unstretched polypropylene film (pyrene film-CTP1128 (trade name); thickness: 30 μm; Toyobo ( Co., Ltd.) was laminated by dry lamination using a urethane adhesive at a coating amount of 5 g / m ² to obtain a substrate (support).
Further, a coating solution for forming a receiving layer having each composition shown in Table 1 was applied onto the unstretched polypropylene film using a Mayer bar so that the coating amount was 5.0 g / m ^2, and then dried. Then, each image receiving sheet was prepared by forming a receiving layer.

[Characteristic evaluation]
(Transferability (print quality))
Each of the image receiving sheets obtained in Examples 1 to 21 and Comparative Examples 1 to 3 was cut into a size of 100 × 140 mm. A sublimation transfer ribbon for the printer is set in a sublimation thermal transfer printer (Digital Photo Printer SPP-2020 (trade name); manufactured by Samsung), and printing is performed on each of the image receiving sheets with gradation of 32 gradations. The image quality unevenness was visually observed, and the transferability (print quality) was evaluated according to the following evaluation criteria. The evaluation results are also shown in Table 2. Note that the gradation gradually increases in density as the first gradation shifts to the 32nd gradation.
Moreover, the optical reflection density in each gradation was measured using a Macbeth RD-918 (trade name; manufactured by Gretag Macbeth) reflection densitometer, and evaluated according to the following evaluation criteria.
<Evaluation criteria for transferability (print quality)>
○: Image quality unevenness was not recognized in all gradations (good transferability (print quality)).
Δ: Although some image quality unevenness was observed in the first to second gradations, image quality unevenness was not observed in other gradations (transferability (print quality acceptable in practical use)).
X: Image quality unevenness was observed not only in the first to second gradations but also in the third and subsequent gradations (transferability (print quality unacceptable for practical use)).
<Evaluation criteria for optical reflection density>
○: 2.0 or more (good high print density)
Δ: 1.7 to less than 2.0 (practically acceptable print density)
×: Less than 1.7 (low print density unacceptable for practical use)

(Silentness during printing)
For each of the image-receiving sheets obtained in Examples 1 to 21 and Comparative Examples 1 to 3, the above-described printer and sublimation transfer ribbon were used, and a black solid image in which yellow, magenta, and cyan were superimposed with the maximum energy value of the thermal head. The image is printed (printing environment: temperature 23 ° C., humidity 53%), and the peeling sound between the transfer sheet and the image receiving sheet at that time is confirmed by a panel test of 10 panelists, and the quietness during printing according to the following evaluation criteria Evaluated. The evaluation results are also shown in Table 2.
<Evaluation criteria>
○: All the panels felt that the peeling sound did not matter (high silence).
Δ: 80 to 90% of the panel felt that the peeling sound was not a concern (practically acceptable quietness).
X: More than 80% of the panel felt that the peeling sound was anxious (a large peeling sound that was unacceptable for practical use).
XX: Sticking between the image receiving sheet and the transfer sheet occurred.

(Quietness when printing in high temperature / high humidity environment)
The same procedure as the evaluation procedure for quietness at the time of printing described above was repeated except that the test was performed in a high temperature / high humidity environment with a temperature of 60 ° C. and a humidity of 85%. Were evaluated according to the same evaluation criteria. The evaluation results are also shown in Table 2.
(Quietness when printing in low temperature / low humidity environment)
The same procedure as the evaluation procedure for quietness at the time of printing described above was repeated except that the test was performed in a low sound / low humidity environment at a temperature of 0 ° C. and a humidity of 5%, and the quietness at the time of printing in a low sound / low humidity environment was the same as above. Evaluation was performed according to the evaluation criteria. The evaluation results are also shown in Table 2.

(Light resistance evaluation)
For each of the image-receiving sheet samples of Examples 1 to 21 and Comparative Examples 1 to 3 prepared in the transferability evaluation described above, the tone of the optical reflection density of cyan is about 1.0, and the xenon fade meter Ci-35A ( (Trade name; manufactured by Atlas Co., Ltd.) was used to measure the residual optical density of cyan after 96 hours of xenon lamp irradiation, and the light resistance was evaluated according to the following evaluation criteria.
○: Optical density residual ratio is 85% or more (good high light resistance)
Δ: Residual ratio of optical density is 70% or more and less than 85% (light resistance practically acceptable)
X: Optical density residual ratio is less than 70% (low light resistance unacceptable for practical use)

(Examples 22 to 23 and Comparative Example 4)
A sublimation transfer image-receiving sheet was obtained according to the same procedure as in Example 1 except that each coating solution having the following composition was used as the receiving layer coating solution.
<Coating liquid of Example 22>
Polyester resin (Byron 290) 8 parts Optical brightener (Ubitex OB (trade name); manufactured by Ciba Specialty Chemicals)
0.03 parts Compound of formula (1) (Hostabin PR-25 Gran.) 1.97 parts Toluene / methyl ethyl ketone (1/1) 100 parts <Coating liquid of Example 23>
Polyester resin (Byron 290) 6 parts Optical brightener (Ubitex OB (trade name); manufactured by Ciba Specialty Chemicals)
0.03 part Compound of formula (2) (hostabin B-CAP) 1.97 parts Titanium oxide 2 parts Toluene / methyl ethyl ketone (1/1) 100 parts <Coating liquid of Comparative Example 4>
Polyester resin (Byron 290) 6 parts Optical brightener (Ubitex OB (trade name); manufactured by Ciba Specialty Chemicals)
0.03 parts Benzotriazole UV absorber (Tinuvin 328) 1.97 parts Titanium oxide 2 parts Toluene / methyl ethyl ketone (1/1) 100 parts

(Examples 24-26)
On the base material, an intermediate layer coating solution having the following composition is applied using a bar coater so that the coating amount after drying is 5 g / m ² and dried to form an intermediate layer. Each sublimation transfer image-receiving sheet was obtained in the same manner as in Examples 1, 8 and 15 except that the receiving layer was formed thereon.
<Intermediate layer coating solution>
Polyester resin (Byron 600 (trade name); manufactured by Toyobo Co., Ltd.) 7.97 parts Optical brightener (Ubitex OB (trade name); manufactured by Ciba Specialty Chemicals)
0.03 part Titanium oxide 2 parts Toluene / methyl ethyl ketone (1/1) 100 parts The receiving layer of Example 24 is that of Example 1, the receiving layer of Example 25 is that of Example 8, and the receiving layer of Example 26. The layer was formed using a coating solution having the same composition as in Example 15.

(Examples 27 to 29)
On the base material, an intermediate layer coating solution having the following composition is applied using a bar coater so that the coating amount after drying is 5 g / m ² and dried to form an intermediate layer. Each sublimation transfer image-receiving sheet was obtained in the same manner as in Examples 1, 8 and 15 except that the receiving layer was formed thereon.
<Intermediate layer coating solution>
Polyester resin (Byron 600 (trade name); manufactured by Toyobo Co., Ltd.) 6.47 parts Compound of formula (1) (Hostabin PR-25 Gran.) 1.50 parts Fluorescent whitening agent (Ubitex BAC (trade name) Manufactured by Ciba Specialty Chemicals) 0.03 parts Titanium oxide 2 parts Toluene / methyl ethyl ketone (1/1) 100 parts The receiving layer of Example 27 is Example 1 and the receiving layer of Example 28 is Example 8. Further, the receiving layer of Example 29 was formed using a coating solution having the same composition as that of Example 15.

(Comparative Example 5)
A sublimation transfer image-receiving sheet was obtained in the same manner as in Example 24 except that the coating solution of Comparative Example 1 was used as the receiving layer coating solution.
<Color measurement>
Using the color difference meter (CR-221 (trade name); manufactured by Konica Minolta), the Lab value of the receiving layer surface of each of the sublimation transfer image-receiving sheets of Examples 22 to 29 and Comparative Examples 4 to 5 obtained by the above procedure was used. And measured by the Hunter color method. Table 3 shows the measurement results.

Claims (6)

A sublimation transfer image-receiving sheet provided with a receiving layer on a substrate, wherein the receiving layer has the following formula (1):

Following formula (2):

And the following formula (3):

A sublimation transfer image-receiving sheet comprising at least one compound represented by the formula:   The sublimation transfer image receiving sheet according to claim 1, wherein the receiving layer further contains at least one selected from a fluorescent brightening agent, titanium oxide, zinc oxide, and cerium oxide.   An intermediate layer is further provided between the substrate and the receiving layer, and the intermediate layer is a compound represented by the above formulas (1) to (3), a fluorescent brightener, titanium oxide, zinc oxide, and cerium oxide. The sublimation transfer image receiving sheet according to claim 1, which contains at least one selected from the group consisting of: A sublimation transfer image-receiving sheet having a receiving layer provided on a substrate via an intermediate layer, wherein the intermediate layer has the following formula (1):

Following formula (2):

And the following formula (3):

A sublimation transfer image-receiving sheet comprising at least one compound represented by the formula:   The sublimation transfer image-receiving sheet according to claim 4, wherein the intermediate layer further contains at least one selected from a fluorescent brightening agent, titanium oxide, zinc oxide, and cerium oxide.   6. The sublimation transfer image receiving sheet according to claim 4, wherein the receiving layer contains at least one selected from a fluorescent brightening agent, titanium oxide, zinc oxide, and cerium oxide.