JPS61242877A - Thermal transfer sheet for multicolor image - Google Patents

Abstract

PURPOSE:To obtain a clear full-color multicolor image high in density and free of stickiness, by providing a combination of leuco dye layer capable of forming respective colors with a heat-fusible substance layer as a recurring unit. CONSTITUTION:The thermal transfer sheet is provided, on the same base, with leuco dye layers capable of forming respective colors for multicolor images and a heat-fusible substance layer. In general, leuco dye layers capable of forming respective colors of yellow C, magenta B, cyan A and black D are selected, a transfer sheet is laid on a receiving sheet, and heating energy is applied to the laminate from the back side of the transfer sheet, whereby the leuco dyes are transferred from the transfer sheet onto the receiving sheet, then the transfer sheet is moved, and the heat-fusible substance layer E is brought into contact with the surface of images transferred to the receiving sheet, followed by heating. Accordingly, the surface of the transferred images formed on the receiving sheet is covered by a film of the heat-fusible substance, and as a result, stickness of the transferred images is eliminated, and ground contamination of the receiving sheet due to stickness of the transferred images can be obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive transfer sheet for polygonal images having a transfer layer containing a leuco dye used in combination with a receiving sheet having a color developer layer.

[Prior art]

Conventionally, thermal transfer methods have used a transfer sheet in which a heat-sublimable dye is provided on a support, or a transfer sheet in which a heat-fusible substance and a pigment with a different tone are provided on a support, and a receiving sheet is attached to this transfer sheet. A method of forming a transferred image on a receiving sheet by overlapping and thermal printing is known. however,
When using a transfer sheet in which a heat sublimable dye is provided on a support, the gradation expression of image density is excellent, but there are drawbacks such as low heat sensitivity and poor storage stability. on the other hand.

In the case of a heat-sensitive transfer sheet in which a heat-fusible substance and pigment are provided on a support, it has excellent heat sensitivity and storage stability, but it cannot express gradation of image density, so it is difficult to obtain clear, full-color images. The disadvantage is that it cannot be done.

It is also known to obtain multicolor images using a combination of a transfer sheet having a leuco dye layer and a receiving sheet having a developer layer. In this case, although the gradation of the image density is excellent, there are drawbacks such as stickiness in the transferred image and background staining on the receiving sheet.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive transfer sheet for multicolor images that can produce clear full-color multicolor images with high density and no stickiness.

〔composition〕

According to the present invention, it is used in combination with a receptor sheet having a color developer layer, and has a leuco dye layer that develops yellow, magenta, cyan, and black colors for multicolor development, and further has a thermofusible leuco dye layer. There is provided a heat-sensitive transfer sheet for multicolor images, which has a material layer and is characterized in that a combination of a leuco dye layer that develops each color and a thermofusible material layer is configured as a repeating unit.

The heat-sensitive transfer sheet of the present invention has a leuco dye layer and a heat-fusible material layer that develop different colors for multiple colors on the same support. The leuco dye layer that develops color and the thermofusible material layer form a set, and the set is constructed as a repeating unit on the support.

The multicolor leuco dye layer used in the present invention may be of any color as long as it develops a desired color, but generally yellow,
A leuco dye layer that develops magenta, cyan, and black colors is selected. By using such four leuco dye layers, seven full colors can be easily obtained. That is, the leuco dye layer that develops each color of yellow, magenta, cyan, and black can be used alone to produce each color, and the combination of a leuco dye layer that develops yellow and a leuco dye layer that develops magenta can be used. By combining a leuco dye layer that develops red and yellow colors and a leuco dye layer that develops cyan color, blue color can be obtained by combining a leuco dye layer that develops green and cyan colors and a leuco dye layer that develops magenta color. can.

Next, the thermal transfer sheet of the present invention will be explained with reference to the drawings.

FIG. 1 shows a plan view of one embodiment of the thermal transfer sheet of the present invention, which shows a leuco dye layer A that develops a cyan color, a leuco dye layer B that develops a magenta color, a leuco dye layer that develops a yellow color, and a thermosensitive transfer sheet. An example is shown in which the fusible material layers E are arranged on the support in that order and these layers A-E are constructed as a repeating unit. FIG. 2 shows a plan view of another embodiment of the heat-sensitive transfer sheet of the present invention, showing an example in which a thermofusible material layer E is disposed between each leuco dye layer.

The layer F shown in FIGS. 1 and 2 is provided at the boundary of each repeating unit, is an ink mark layer for detecting the boundary, and is usually composed of a black ink mark layer. The heat-sensitive transfer sheet as described above is produced by printing on a support (e.g., paper, synthetic paper, plastic film, etc.) by letterpress printing, gravure printing, etc. using each leuco dye liquid and thermofusible substance liquid as ink. It can be easily created by applying it to An example of such a heat-sensitive transfer sheet is shown in Japanese Patent Application No. 58-100686.

The thermofusible material layer used in the present invention is provided for the purpose of eliminating stickiness of the transferred image and obtaining a clear transferred image without background stains caused by the transferred image. That is, the transfer sheet of the present invention and the receiving sheet are stacked, heating energy is applied from the back side of the transfer sheet to transfer the leuco dye from the transfer sheet onto the receiving sheet, and then the transfer sheet is moved and the receiving sheet is A thermofusible material layer is brought into contact with the surface of the transferred image and heated. Through this operation, the surface of the transferred image formed on the receiving sheet is coated with a film of a thermofusible substance, and as a result, the transferred image is no longer sticky, and the background stain of the receiving sheet due to the stickiness of the transferred image is prevented. Prevented.

The thermofusible substance used in the present invention is a substance that is solid or semi-solid at room temperature and that can form a continuous film when in the solid state, and at a temperature below the melting point of the leuco dye, usually below 100°C. It refers to a substance that melts and exhibits a low melt viscosity. Specific examples of such waxes include animal waxes such as beeswax and spermaceti, vegetable waxes such as candelilla wax, rice wax, and carnauba wax, mineral waxes such as montan wax and osikerite, and paraffin. Examples include waxes, petroleum waxes such as microcrystalline wax, modified waxes that are various other wax derivatives, hydrogenated waxes such as castor wax, various long-chain fatty acids and their salts, and the like. The amount of adhesion of this thermofusible substance to the support is 0.
．． The amount is about 5 to 2 g//; if it is too large, the heat sensitivity will decrease, and if it is too small, the effect of preventing skin stains will be reduced.

As the leuco dyes that develop yellow, magenta, cyan, and black colors used in the present invention, any of those conventionally used for pressure-sensitive paper and thermal paper can be used, including triphenylmethane-based, fluoran-based, Phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based agents are preferably applied. Specific examples of these leuco dyes are shown below, but of course the present invention is not limited thereto.

Yellow dyes: 3.6-simethoxyfluorane, 3-cyclohexylamino-6-chlorofluoran, 3-(p-dimethylaminophenyl)-3-phenylphthalide, etc.

Magenta dye: 3-diethylamino-7,8-benzfluorane, 3-
diethylamino-6-methyl-7-chlorofluorane,
3-di(l-ethyl-2-methylindole)-3-yl-phthalide, 3-diethylamino-6-phenyl-7
-Azafluoran etc.

Cyan dye: 3,3-bis(p-dimethylaminophenyl)-phthalide, 3,3-bis(p-dimethylaminophenyl)-6
-Simethylaminophthalide (also known as crystal violet lactone), 3.3-bis(P-diethylaminophenyl)-6-dimethylaminophthalide, 2-bis(P-dimethylaminophenyl)methyl-5- Dimethylamino-benzoic acid, 3-(p-dimethylaminophenyl)-3-(p-dibenzylaminophenyl) phthalide, and the like.

Black dye: 3-N-methyl-N-cyclohexylamino-6-methyl-7-7nilinofluorane, 3-diethylamino-6
-Methyl-7-anilinofluorane, 3-diethylamino-7-piperidinofluorane, etc.

Further, as the color developer used in the present invention, an electron-accepting substance such as a phenolic substance, an organic acid, or a salt or ester thereof is used, and from the viewpoint of practicality, one with a melting point of 200°C or less is preferably used. Applicable. Specific examples of color developers preferably applied in the present invention are shown below. Note that the numbers in parentheses indicate the melting point.

4-tert-butylphenol (98), 4-hydroxydiphenyl ether (84), 1-naphthol (
98), 2-naphthol (121), methyl-4-hydroxybenzoate (131), 4-hydroxyacetophenone (109), 2,2'-dihydroxydiphenyl ether (79), 4-phenylphenol (16)
6), 4-tart-octylcatechol (109
), 2,2'-dihydroxydiphenyl (103),
4.4'-methylenebisphenol (160), 2
,2'-methylenebis(4-chlorophenol) (
164), 2,2'-methylenebis(4-methyl-6
-tart-butylphenol) (125), 4.4
'-isopropylidenediphenol (156), 4,
4'-isopropylidene bis(2-chlorophenol) (90), 4,4'-isopropylidene bis(2,
6-dibromophenol) (172), 4,4'-isopropylidene bis(2-tert,-butylphenol) (110), 4,4'-isopropylidene bis(
2-methylphenol) (136), 4,4'-isopropylidene bis(2,6-dimethylphenol) (1
68), 4.4'-5ec-butylidene diphenol (119), 4.4'-5ea-butylidene bis(
2-methylphenol) (142), 4,4'-cyclohexylidene diphenol (180), 4,4'
-Cyclohexylidenebis(2-methylphenol)
(184), salicylic acid (163), salicylic acid methalyl ester (74), salicylic acid phenacyl ester (110), 4-hydroxybenzoic acid methyl ester (131), 4-hydroxybenzoic acid ethyl ester (
116), 4-hydroxybenzoic acid propyl ester (
98), 4-hydroxybenzoic acid isopropyl ester (86), 4-hydroxybenzoic acid butyl ester (
71), 4-hydroxybenzoic acid isoamyl ester (
50), 4-hydroxybenzoic acid phenyl ester (1
7g), 4-hydroxybenzoic acid benzyl ester (1
11), 4-hydroxybenzoic acid cyclohexyl ester (119), 5-hydroxysalicylic acid (200),
5-Chlorsalicylic acid (172), 3-chlorsalicylic acid (17g), thiosalicylic acid (164), 2-chloro-5-nitrobenzoic acid (165), 4-methoxyphenol (53), 2-hydroxybenzyl alcohol ( 8
7), 2,5-dimethylphenol (75), benzoic acid (122), orthotoluic acid (107), metatoluic acid (111), paratoluic acid (181), orthochlorobenzoic acid (142), metaoxybenzoic acid (200)
), 2,4-dihydroxyacetophenone (97), resorcinol monobenzoate (135), 4-hydroxybenzophenone (133), 2,4-dihydroxybenzophenone (144), 2-naphthoic acid (184), 1-hydroxy -2-naphthoic acid (195), 3,4-dihydroxybenzoic acid ethyl ester (128), 3,4-dihydroxybenzoic acid phenyl ester (189), 4-hydroxypropiophenone (150), salicyl salicylate ( 1
48), phthalic acid monobenzyl ester (107), 1
, 1-bis(4'-hydroxyphenyl)ethane (1
26), 1.1-bis(4'-hydroxyphenyl)
Propane (130), 1,1-bis(4'-hydroxyphenyl)hexane (111), 1,1-bis(4'
-hydroxyphenyl)hebutane (120).

■, 1-bis(4'-hydroxyphenyl)-2-propylpentane (128)% 1.1-bis(4'-hydroxyphenyl)-2-ethylhexane (87), 2
,2-bis(4'-hydroxyphenyl)butane(1
01), 3,3-bis(4'-hydroxyphenyl)
Hexane (iss).

1.1-bis(3'-methyl-4'-hydroxyphenyl)ethane (101), 1.1-bis(3'-methyl-4'-hydroxyphenyl)propane (94), 1,
1-bis(3'-methyl-4'-hydroxyphenyl)
Butane (135) 1,1-bis(3'-methyl-4'
-hydroxyphenyl)pentane (97), 1,1-bis(3'-methyl-41-hydroxyphenyl)hexane (78), 1,1-bis(3'-methyl-4'-
hydroxyphenyl)hebutane (85), 2-(3'
-methyl-4'-hydroxyphenyl)-2-(4'
-hydroxyphenyl)propane (120), 2.2
-bis(3'-methyl-4'-hydroxyphenyl)
Pentane (128), 2,2-bis(5'-methyl-41-hydroxyphenyl)hexane (104).

2.2-bis(3'-methyl-4'-hydroxyphenyl)4-methylpentane (129), 1.1-bis(
3′-me.

methyl-4'-hydroxyphenyl)4-methylbutane (
124), 3,3-bis(3'-methyl-4'-hydroxyphenyl)hexane (90), 5,5-bis(3'
-Methyl-4'-hydroxyphenyl)nonane (12
8), 2-(4'-hydroxyphenyl)-2-(3
'-chloro-4'-hydroxyphenyl)propane (101), 2,2-bis(3'-isopropyl-
4'-Hydroxyphenyl)propane (97), 2.2
-bis(3'-tert-butyl-4'-hydroxyphenyl)propane (117)2.2-bis(3'-
Chlor-4'-hydroxyphenyl)propane (84)
, 2-(4'-hydroxy-3',5'-dimethylphenyl)-2-(4'-hydroxyphenyl)propane (127), bis(3'-methyl-5'-ethyl-
4'-Hydroxyphenyl)methane (105), 1.1
-(3'-methyl-5'-butyl-4'-hydroxyphenyl)butane (104), 2.2-bis(4-hydroxyphenyl)octane<83), bis(4-hydroxyphenylmercapto)methane (55 ), 1,2-bis(4-hydroxyphenylmercapto)ethane (17
3), 1,3-bis(4-hydroxyphenylmercapto)propane (82), 1,4-bis(4-hydroxyphenylmercapto)butane (182), 1,5-bis(4-hydroxyphenylmercapto)pentane (98
), 1,6-bis(4-hydroxyphenylmercapto)hexane (166), 1,3-bis(4-hydroxyphenylmercapto)acetone (74), 1,5-bis(4-hydroxyphenylmercapto)-3 -Oxapentane (93), 1,7-bis(4-hydroxyphenylmercapto)-3,5-dioxahebutane (10g)
, 1,8-bis(4-hydroxyphenylmercapto)-3,5-dioxaoctane (100), etc.

When providing a leuco dye layer and a color developer layer on a support, the leuco dye and color developer are usually added in an amount of 0.1 to
20g/resistant, preferably 0.3-10g/coating Jt
(based on dry solid matter), and as a binder for supporting the leuco dye and color developer on the support, it is preferable to contain a resin having a melting point or softening point of 50 to 130°C. However, in this case, either thermoplastic or thermosetting resin can be used. The resin having a melting point preferably has a melting point of 130° C. or lower in consideration of the heat resistance and heat sensitivity of the transfer sheet.

It is sufficient from the viewpoint of thermal sensitivity that the resin has a softening point of 130° C. or lower. Specific examples of such resins include, for example, primary resins.

Polyethylene, polypropylene, polystyrene, petroleum resin, acrylic resin, vinyl chloride resin, vinyl acetate resin,
Vinylidene chloride resin, polyvinyl alcohol, cellulose resin, polyamide, polyacetal, polycarbonate, polyester, fluororesin, silicone resin, natural rubber, chloride rubber, butadiene rubber, olefin rubber, phenolic resin, urea resin, melamine resin, epoxy resin,
polyimide etc.

The resins mentioned above can be used in the form of a single polymer, a copolymer, or a mixture of a plurality of resins. The amount of this resin used is in the range of 0.01 to 1 part by weight per 1 part by weight of the leuco dye or color developer.If the amount of the resin is less than 0.01 part by weight, the layer on the support will be damaged. The binding force weakens, making it impossible to support the leuco dye and color developer on the support with sufficient adhesion force.On the other hand, if the amount exceeds 1 part by weight, the thermal sensitivity of the product decreases, resulting in poor yield. The transferred image density becomes low. The amount of resin is 0.05 to 1 part by weight of leuco dye or color developer.
It is preferable to use the amount in an amount of 0.5 parts by weight in order to obtain uniform image density during multiple transfers.

In the present invention, in order to obtain a multicolor image using the heat-sensitive transfer sheet, the receiving layer of the receiving sheet is overlaid on the transfer layer surface (the surface containing the leuco dye layer and the thermofusible material layer) of the heat-sensitive transfer sheet, and the color tone is Depending on the information, thermal printing is performed from the back side of the heat-sensitive transfer sheet using a heating means such as a thermal printer, and a multicolor image is formed on the receiving sheet by the reaction between the leuco dye and the color developer, and then a thermofusible image is printed. By bringing the material layer into contact with the transferred image surface and heating it, a film of the thermofusible material may be formed on the image surface.

〔effect〕

The present invention is a thermal transfer sheet having the above structure, and when performing thermal transfer in combination with a receiving sheet, a leuco dye layer that develops different colors for multicolor development of the thermal transfer sheet is applied to the receiving sheet. A multicolor image can be obtained by sequentially overlapping and developing colors, and the obtained colored image is non-sticky. Therefore, when the thermal transfer sheet of the present invention is used as a type ribbon, the running of the type ribbon is It has good properties and does not cause background stains on the receiving sheet.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Example 1 (1) Preparation of transfer sheet (A) (Cyan) dye liquid 3.3-bis(p-diethylaminophenyl)-6-dimethylaminophthalide 10 parts Polyester resin 2 parts Methyl ethyl ketone
100 parts (B) (magenta) dye liquid 3-diethylamino-6-methyl-7-chlorofluoran 10 parts polyester resin
2 parts methyl ethyl ketone
100 parts (C) (yellow) dye solution 3-cyclohexylamino-6-chlorofluorane 10 parts polyester resin 2 parts methyl ethyl ketone 100 parts (D) black dye solution 3-N-methyl-N-cyclohexylamino-6-methyl- 7-anilinofluorane 10 parts Polyester resin 2 parts Methyl ethyl ketone
100 parts (E) Thermofusible substance liquid polyethylene wax (melting point 80°C) 10 parts Vinyl acetate resin 1.5 parts Toluene
Using 100 parts of the above coating solution and a commercially available black ink solution, printing was carried out on a 6 μm thick polyester film using a 6-color gravure printing machine to produce a transfer sheet having the structure shown in FIG. 1. In this case, the dry coating amount of each layer was Ig/I.

(2) Preparation of receptor sheet 2.2-bis(4'-hydroxyphenyl)hebutane 20 parts Silica fine particles (oil absorption 2001Q/100 g)
10 parts polyvinyl alcohol
3 parts water
Using a ball mill, a composition consisting of 100 parts of
After being dispersed for 0 hours, it was coated and dried on the surface of high-quality paper (basis weight 35 g/%) using a wire bar to give a dry adhesion weight of 5 g/%.
A receiving sheet of rrr was obtained.

Example 2 In Example 1, as the leuco dye in the cyan dye solution,
3,3-bis(p-dimethylaminophenyl) phthalide was used, 3-diethylamino-7,8-benzfluorane was used as the leuco dye in the magenta dye solution, and 3-(P) was used as the leuco dye in the yellow dye solution. -dimethylaminophenyl)-3-phenyl-phthalide as a leuco dye in the black dye solution, 3-diethylamino-6
A transfer sheet was produced in the same manner except that -methyl-7-anilinofluorane was used and polyethylene wax with a melting point of 75° C. was used as the thermofusible substance of the thermofusible substance liquid.

Comparative Example 1 A comparative transfer sheet was prepared in the same manner as in Example 1, except that the thermofusible material layer was not used.

Each of the transfer sheets obtained above was used as a type ribbon, the receiving sheet shown in Example 1 was used as a type paper, the two were stacked, and heat was applied from the back side of the transfer sheet using a thermal head of a thermal printing typewriter. Images were recorded by changing the In this case, when forming images using the transfer sheets of Examples 1 and 2, after the image formation, a thermofusible material layer was brought into contact with the image, and thermal printing was performed under the same conditions as the image formation. . The results are shown in the table below.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the heat-sensitive transfer sheet of the present invention, and FIG. 2 is a plan view showing another embodiment of the heat-sensitive transfer sheet of the present invention. A... Leuco dye layer that develops cyan color B... Leuco dye layer that develops magenta color C... Leuco dye layer that develops yellow color D... Leuco dye layer that develops black color E... Heatable fusible material layer

Claims (1)

[Claims] (1) It is used in combination with a receptor sheet having a color developer layer, and has a leuco dye layer that develops yellow, magenta, cyan, and black colors for multicolor development, and further includes a thermofusible material layer. 1. A heat-sensitive transfer sheet for multicolor images, characterized in that a combination of a leuco dye layer and a thermofusible material layer that develops each color is configured as a repeating unit.