JP3170899B2 - Thermal transfer recording sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording sheet, and more particularly, to a thermal transfer recording sheet which can use general-purpose plain paper as recording paper.

[0002]

2. Description of the Related Art Conventionally, as a thermal transfer recording method, a thermal transfer recording sheet having a coloring material layer containing a dye and an image receiving body having an image receiving layer for dyeing the dye are overlapped so that the respective layers face each other. A method in which a dye is transferred onto an image receiving body by heating the back surface of a thermal transfer recording sheet by a heating means such as a thermal head is generally well known and widely used. However, according to this recording method, the recording paper is limited to an image receiving paper having a specific image receiving layer, and it is not easy to use the paper in terms of simplicity and cost. Therefore, a thermal transferable image receiving layer is provided on a sublimation type thermal transfer recording sheet, and the thermal transferable image receiving layer is first thermally melt-transferred from the sheet onto the recording paper, and then the color material or dye is transferred from the color material layer to the image receiving layer. Thus, a sublimation type thermal transfer recording sheet has been proposed which is devised so that general-purpose plain paper can be used as the recording paper (see, for example, JP-A-61-8).
No. 6289). Further, the present inventors have previously used a general-purpose plain paper as a recording paper to overcome the disadvantage that the color reproducibility of an image is inferior due to insufficient whiteness. A configuration in which a white hiding layer containing a white pigment and a transparent receiving layer are sequentially laminated has been proposed (Japanese Patent Application No. Hei 3-100063).

[0003]

When a general-purpose plain paper which is generally commercially available is used as a recording paper without using such a special paper, first, a heat-melt transferable image-receiving layer is first used as a heat transfer recording sheet. It is used by being melt-transferred from the base material onto plain paper.However, the conventional white opaque layer composed of a white pigment and a binder resin has insufficient adhesiveness to plain paper and has a heat-receiving portion and a receiving portion of the transfer image receiving layer. There was an inconvenience that the end was not cut smoothly. Therefore, the present inventors have previously proposed that the white hiding layer contains a plasticizer such as dioctyl phthalate in order to improve the adhesiveness and the edge cut (Japanese Patent Application No. 3-300753). . However, these general plasticizers have another drawback that they lack the stability of an image, and it has been required to achieve both the adhesion and the stability of the image with the cut edge. The present invention provides a sublimation type thermal transfer recording sheet which can solve such a problem.

[0004] That is, an object of the present invention is to provide a thermal transfer recording sheet capable of easily transferring a clear image with good color reproducibility on an extremely wide range of plain paper. During thermal transfer of the layer, the adhesiveness to the recording paper is excellent, and the boundary between the heat-applied part and the non-applied part is cut (edge cut).
And to provide a thermal transfer recording sheet having excellent transfer image stability.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thermal transfer recording sheet comprising a substrate provided with an image receiving layer which can be transferred onto a recording paper by heat. A dibasic acid ester compound comprising a structure in which at least a transparent receiving layer and a white hiding layer are sequentially laminated on a material, and wherein the white hiding layer comprises an aliphatic alcohol component having 12 or more carbon atoms and a dibasic acid component Is achieved by a thermal transfer recording sheet characterized by containing:

Hereinafter, the present invention will be described in detail. The white hiding layer of the present invention is composed of a combination of a white pigment, a binder resin and a dibasic acid ester compound. , Binder 0.1
To 20, the dibasic acid ester compound 0.01 to 10 (weight ratio), preferably 1 to 0.5 to 5 and 0.1 to 0.5, respectively.
05 to 2.5 (weight ratio). The mixing ratio of the dibasic acid ester compound to the binder resin 1 was 0.02.
０．５0.5 (weight ratio), preferably 0.0 to 1
2 to 0.3 (weight ratio), and 0.02 to 1
0.2 (weight ratio) is preferred.

As the dibasic acid ester compound used in the present invention, an aliphatic alcohol having 12 or more carbon atoms is used as an alcohol component, for example, dodecyl alcohol, myristyl alcohol, hexadecyl alcohol,
Stearyl alcohol, isostearyl alcohol,
Behenyl alcohol, octyldodecyl alcohol and the like. As the dibasic acid component, adipic acid,
Sebacic acid and phthalic acid. Of these, particularly preferred are ester compounds of an alcohol component having 18 to 32 carbon atoms and an aliphatic dibasic acid component.

The dibasic acid ester compound used in the present invention is preferably one having high compatibility in combination with the binder resin for the white hiding layer. Specifically, the dibasic acid ester compound has a solubility parameter close to that of the binder resin. It is good to select what you have. However, for the purpose of minimizing the effect on the coloring matter forming an image, it is preferable to select one in which each dissolution parameter satisfies the relational expression of coloring matter> binder resin ≧ plasticizer.

As the binder resin, resins generally known as thermoplastic resins, for example, saturated polyester resins, acrylic resins, methacrylic resins, styrene resins, polycarbonate resins, vinyl chloride resins, polyvinyl acetal resins, vinyl chloride / vinyl acetate Copolymer resins and the like can be used. Examples of the white pigment include titanium oxide, zinc oxide, calcium carbonate, talc, clay and the like. It is also effective to add various optical brighteners for the purpose of supplementing whiteness.

The resin used in the transparent receiving layer of the present invention includes saturated polyester, acrylic resin, methacrylic resin, styrene resin, polycarbonate resin, cellulose acetate, polyvinyl acetal resin, polyvinyl phenyl acetal resin, vinyl chloride resin, vinyl chloride. Resins having a dyeing property with respect to a vaporizable or heat diffusible dye such as a vinyl acetate copolymer resin, a polyarylate resin, an AS resin, or the above-mentioned crosslinked product are exemplified.

In the present invention, each of these layers basically has a two-layer structure in which a transparent receiving layer and then a white hiding layer are sequentially laminated from the substrate surface side as shown in FIG. Although the image receiving layer is constituted, the present invention is not limited to this, and may be provided between the substrate surface and the transparent receiving layer, between the transparent receiving layer and the white hiding layer, and on the surface of the white hiding layer, for any purpose or as necessary. Other layers can be additionally configured. For example, it is also effective to provide a subbing layer of a release agent such as a silicone-based, ketone-based, or polyvinylacetal-based material on the surface of the substrate in order to facilitate the releasability of the receiving layer and the substrate during thermal transfer.

The method for forming the image receiving layer of the present invention can be arbitrarily selected from commonly used methods, for example, a method using a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, a die coater or the like. (For details, see Yuji Harazaki, “Coating Method,” published by Maki Shoten, 1977). A double coating method using a microgravure method is particularly preferable.

As the substrate, a sheet of polyester, polyamide or the like which has been conventionally used as the substrate of this type of thermal transfer recording sheet can be used as appropriate. The thickness of the receiving layer formed on the substrate is usually 0.1 to 20 μm as a dry film thickness.
m, preferably 1 to 10 μm, more preferably 1 to 6 μm
m. The thickness of the white opaque layer is preferably large for the purpose of reducing surface unevenness of plain paper used as recording paper and concealing a yellowish ground color. However, the dry film thickness is preferably 0.5 to 20 μm, and more preferably 3 to 12 μm, from the viewpoint of coating production. Further, a white hiding layer having a thickness of 1.5 times or more, usually 1.5 to 6 times the thickness of the transparent receiving layer is preferable.

The vaporizable or thermally diffusible dye used in the color material layer for thermal transfer recording used together with the image receiving layer of the present invention includes azo, anthraquinone, nitro and nitro dyes.
Various nonionic dyes such as styryl, naphthoquinone, quinophthalone, azomethine, coumarin, and condensed polycyclic dyes are used. When the thermal transfer recording sheet of the invention is used, the recording paper is not particularly limited, and plain paper made of general-purpose cellulose fibers can be used.

In the thermal transfer recording using the thermal transfer recording sheet of the present invention, first, an image receiving layer is partially transferred from a substrate to plain paper.
Alternatively, after the entire surface is thermally transferred, the color material layer is heated by a heating means such as a thermal head and transferred to the image receiving layer. As a form of forming the thermal transfer recording sheet of the present invention, as shown in FIG. 2, for example, an image receiving layer in which a white opaque layer and a transparent receiving layer are laminated on the same substrate is provided, and yellow (Y), Examples include those in which magenta (M) and cyan (C) color material layers are formed.

According to this method, since both the image receiving layer and the color material layer are integrated with the thermal transfer recording sheet, no extra operation is required, and the image receiving layer transferred to plain paper is limited to only the image portion. This is also very simple and is preferred. However, the present invention is not limited to this, and the entire image receiving layer may be transferred. Further, a sheet coated with only the image receiving layer via the undercoat layer of the present invention may be used in combination with a color sheet having a separate color material layer. The transfer of the image receiving layer and the transfer of the image can be performed by separate operations. Therefore, the thermal transfer recording sheet of the present invention includes various cases as described above.

[0017]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to the examples unless it exceeds the gist thereof. Example-1 (a) Preparation of image receiving layer portion Vinyl chloride / vinyl acetate copolymer resin (trade name: UCRA)
-VYHD, manufactured by Union Carbide Co.) 20 parts by weight, 60 parts by weight of toluene and 1.0 part by weight of an amino-modified silicone (trade name: KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.) as a release agent Liquid (R-1) and vinyl chloride / vinyl acetate copolymer resin (trade name: UC
RA-VYLF, manufactured by Union Carbide) 15 parts by weight, 15 parts by weight of titanium oxide (trade name: R-580, manufactured by Ishihara Sangyo Co., Ltd.), 1 part by weight of diisostearyl adipate, and 60 parts by weight of toluene The coating liquid (R-2) is applied on a biaxially stretched polyethylene terephthalate film (4.5 μm thick) with a heat-resistant lubricated back side by a gravure printing machine in the order shown in Fig. 1 Then, an image receiving layer coated portion having a total dry film thickness of 8 μm (transparent receiving layer 2 μm, white hiding layer 6 μm) was prepared. (B) Preparation of Color Material Layer Part Adjacent to the coating part of the image receiving layer, a yellow color material layer coating solution: 5 parts by weight of a yellow dye represented by the following structural formula (A), phenoxy resin (trade name; PK
HJ, manufactured by Union Carbide Co.) A coating solution (C-1) comprising 10 parts by weight, 90 parts by weight of methyl ethyl ketone, and 10 parts by weight of isopropanol.

[0018]

Embedded image

Magenta color material layer coating solution: The following structural formula (B)
5 parts by weight of a magenta dye represented by the formula, phenoxy resin 1
A coating liquid (C-2) comprising 0 parts by weight, 90 parts by weight of methyl ethyl ketone, and 10 parts by weight of isopropanol.

[0020]

Embedded image

Cyan color material layer coating solution: a coating solution comprising 5 parts by weight of a cyan dye represented by the following structural formula (C), 10 parts by weight of a phenoxy resin, 90 parts by weight of methyl ethyl ketone, and 10 parts by weight of isopropanol (C-3) ).

[0022]

Embedded image

The three color coating solutions are applied in the order shown in FIG.
It dried and the coloring material layer coating part which has a coloring material layer with a dry film thickness of about 1 micrometer each was produced.

(C) Transfer Recording Test The ink-coated surface of the above-described sublimation type thermal transfer recording sheet is laid on a 200 g high-quality paper (manufactured by Kanzaki Paper), and a partial grace having a heating resistor density of 5.4 dots / mm. Recording was performed under the following conditions using a mold line thermal head, and the transfer characteristics were compared and evaluated. The results are shown in Table 1 below.

[0025]

[Table 1] Recording line density 5.4 lines / mm Thermal head applied power 0.20 W Thermal head applied pulse width When transferring the image receiving layer: (a) 14.5 ms (b) 10.0 ms When transferring the image: 0 14.5 ms

(D) Evaluation test of image stability
After being kept in a thermo-hygrostat maintained at a condition of 60% for 2 weeks, the presence or absence of blur at the edge of the image was visually determined, and the results are shown in Table 1 below.

Example 2 In the same manner as in Example 1, except that 1 part by weight of ditridecyloctyl adipate was used as the ester compound in the white hiding layer of the image receiving layer used in Example 1, instead of diisostearyl adipate. The test was performed by the method described in (1), and the results are shown in (Table 1) below.

Example 3 In the white hiding layer of the image receiving layer used in Example 1, an acrylic resin (trade name: DIANAL BR-) was used instead of a vinyl chloride / vinyl acetate copolymer resin as a binder resin.
107, manufactured by Mitsubishi Rayon Co., Ltd.), and the test was conducted in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 1 In the white hiding layer of the image receiving layer used in Example 1, except that dioctyl phthalate was used instead of diisostearyl adipate as the ester compound.
The test was conducted in the same manner as in
This is shown in 1).

Comparative Example 2 In the white hiding layer of the image receiving layer used in Example 1, except that dioctyl adipate was used instead of diisostearyl adipate as the ester compound.
A test was conducted in the same manner as in Example 1 and the results were obtained as shown in Table 1 below.
This is shown in 1).

Comparative Example 3 A test was conducted in the same manner as in Example 1 except that no ester compound was used in the white hiding layer of the image receiving layer used in Example 1, and the results were shown in the following Table. -1).

Comparative Example-4 A test was conducted in the same manner as in Example-3, except that no ester compound was used in the white hiding layer of the image receiving layer used in Example-3, and the results were shown in the following ( The results are shown in Table 1).

[0033]

[Table 2]

[0034]

By using the sublimation type thermal transfer recording sheet of the present invention, excellent adhesiveness to a wide range of plain paper is obtained, the edge of the transfer image receiving layer is cut well, and the stability is excellent. A transfer image can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a portion provided with an image receiving layer of a thermal transfer recording sheet of the present invention.

FIG. 2 is a view showing one embodiment of a thermal transfer recording sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Transparent receiving layer 3 White hiding layer 4 Image receiving layer 5 Yellow color material layer 6 Magenta color material layer 7 Cyan color material layer 8 Thermal transfer recording sheet 9 Recording paper 10 Heat applying material such as a thermal head.

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-63-98494 (JP, A) JP-A-64-87390 (JP, A) JP-A-5-32067 (JP, A) JP-A-5-32067 139056 (JP, A) JP-A-2-153793 (JP, A) JP-A-5-139056 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5 / 38-5 / 40

Claims (3)

(57) [Claims] 1. A thermal transfer recording sheet comprising a substrate provided with an image receiving layer which can be transferred onto a recording paper by heat, wherein the image receiving layer comprises at least a transparent receiving layer and a white hiding layer formed on the substrate in order. A thermal transfer recording sheet having a laminated structure, wherein the white hiding layer contains a dibasic acid ester compound comprising an aliphatic alcohol component having 12 or more carbon atoms and a dibasic acid component. 2. The dibasic acid ester compound having a carbon number of 1
The thermal transfer recording sheet according to claim 1, wherein the sheet is a dibasic acid ester compound comprising 8 to 32 aliphatic alcohol components and an aliphatic dibasic acid component. 3. The mixing ratio (weight ratio) of the white pigment, the binder and the dibasic ester compound in the white hiding layer is such that the binder is 0.1 to 20 and the dibasic ester compound is 0 with respect to 1 white pigment. The thermal transfer recording sheet according to claim 1, wherein the number of the thermal transfer recording sheet is from 0.11 to 10.