JPH0561114B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Industrial Application Field The present invention relates to a thermal transfer recording material with improved image storage stability. More specifically, in a thermal transfer recording material comprising a combination of a transfer sheet having a heat-fusible ink layer on one side of a base material that can be transferred when heated, and an image-receiving sheet that receives a transferred image from the transfer sheet, the heat-fusible UV absorber and/or ink layer
Alternatively, the present invention relates to a thermal transfer recording material whose image storage stability is improved by containing an antioxidant. (B) Prior Art In recent years, color printers and color facsimile machines have been actively developed, and interest in color recording is increasing. In particular, thermal transfer recording is easy to maintain due to its simple device mechanism, has low price and maintenance costs, is capable of clear, high-density recording with low energy consumption, and uses multicolored ink sheets. It has recently been attracting attention because it allows color recording to be performed relatively easily. One of the characteristics of color melt-type thermal transfer recording is that it has good image storage stability. However, the image storage stability of color melt-type thermal transfer recording is
Although it is superior to sublimation-type thermal transfer recording and inkjet recording, when the printed sample is exposed to sunlight or ultraviolet rays for a long period of time, discoloration or blackening is observed, and its light resistance cannot be said to be sufficient for practical use. In color melt-type thermal transfer recording, organic pigments and dyes are often used as coloring materials contained in the ink layer from the viewpoint of color reproducibility. It is thought that these organic pigments and dyes are oxidized and degraded by ultraviolet rays, causing discoloration or blackening. (C) Purpose of the invention The present invention has been made in view of the above circumstances.
This was made in view of the above-mentioned circumstances regarding image storage stability, and the object thereof is to provide a thermal transfer recording material with improved image storage stability. (D) Structure of the Invention That is, the present invention provides a thermal transfer method that combines a transfer sheet having a heat-melting ink layer that can be transferred when heated on one side of a base material, and an image receiving sheet that receives a transferred image from the transfer sheet. By incorporating an ultraviolet absorber and/or an antioxidant into the heat-melting ink layer of the recording material, a thermal transfer recording material with improved image storage stability could be provided. That is, the heat-melting ink in the present invention is
It consists of at least a pigment and/or dye, a thermofusible substance, and an ultraviolet absorber and/or an antioxidant. In the present invention, the melting point of the ultraviolet absorber and antioxidant contained in the heat-melting ink layer is 50 to
150°C is preferred. Those with melting points lower than 50°C cause blocking. Moreover, if the temperature is higher than 150°C, the transfer efficiency will be significantly impaired. Examples of the ultraviolet absorber and antioxidant used in the present invention are listed below, but these do not limit the present invention in any way. UV absorbers Salicylic acid UV absorbers such as p-tert-butylphenyl salicylate and p-octylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2' -dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,
Benzophenone ultraviolet absorbers such as 4'-dimethoxybenzophenone and 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-
(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-
di-tert.-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert.-butyl-
5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert.
Benzotriazole UV absorbers such as -butylphenyl)-5-chlorobenzotriazole and 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, ethyl-2-cyano-
Cyanoacrylate UV absorbers such as 3,3'-diphenyl acrylate, and UV stabilizers such as nickel dibutyl dithiocarbamate, benzoate type quenchers and hindered amines; 2,6-di-tert.-butyl- p-cresol,
Butylated hydroxyanisole, stearyl-β
-(3,5-di-tert.-butyl-4-hydroxyphenyl)propionate, 2,2'-methylene-
Bis-(4-methyl-6-tert.-butylphenol), 2,2'-methylene-bis-(4-ethyl-6
-tert.-butylphenol), and tetrakis-{methylene-3-(3'-5'-di-tert.-butyl-
4′-Hydroxyphenyl)propionate} Phenolic antioxidants such as methane, sulfur-based antioxidants such as dimyristylthiodipropionate and distearylthiodipropionate, and phosphorus-based acid antioxidants Ultraviolet rays such as those mentioned above The content of the absorbent and antioxidant is preferably 10 to 400% by weight of the pigment and/or dye contained in the ink layer on the transfer sheet. If it is less than 10% by weight, sufficient effects cannot be obtained, and if it is more than 400% by weight, the physical properties of the ink deteriorate, resulting in poor transferability, peeling, blocking, etc. In the present invention, the pigments and dyes contained in the heat-melting ink layer are not limited at all. Generally, in color melt-type thermal transfer recording, organic pigments and dyes are used for color reproducibility. In the present invention, the effect is remarkable for organic pigments and dyes, but the same effect is shown for inorganic pigments as well. Organic pigments include azo pigments (monoazo, bisazo, condensed azo pigments), dyeing lake pigments (acid dye lake, basic dye lake, mordant dye lake pigments), nitro pigments,
Nitroso pigments, phthalocyanine pigments, high-grade pigments (vat dye pigments, metal complex pigments, perylene pigments,
Examples include isoindolinone pigments and quinacridone pigments). To give a more specific example, the azo pigment is Hansa Yellow G (CI11680
(The numbers in brackets below indicate CI No.), Hansa Yellow R
(12710), Pyrazolone Red B (21120), Permanent Red R (12085), Lake Red C (15585),
Brilliant Carmine 6B (15850), Permanent Carmine FB (12490) (monoazo pigments), Benzidine Yellow G (21090), Benzidine Yellow GR
(21100), Permanent Yellow NCR (20040) (bisazo pigments), Chromophthal Yellow, Chromophthal Red (condensed azo pigments), etc. Dyeing lake pigments include quinoline yellow lake (47005), eosin lake (45380), alkali blue lake (42750A, 42770A) (all pigment dye lake pigments), rhodamine lake B (45170),
Examples include methyl violet lake (42535), Victoria blue lake (44045), malachite green lake (42000) (all basic dye lake pigments), and alizarin lake (58000) (mordant dye lake pigment). Naphthol Yellow S as a nitro pigment
(10316), nitroso pigments include Pigment Green B (10006) and naphthol green B (10020), and phthalocyanine pigments include metal-free phthalocyanine blue (74100), phthalocyanine blue (74160), and phthalocyanine green (74260). High-grade pigments include Anthrapyrimidine Yellow (68420), Indanthrene Brilliant Orange GK (59305), and Indanthrene Blue RS.
(69800), Thioindigo Red B (73300) (vat dye pigments), Nickel Azo Yellow (12775)
(metal complex pigment), perylene red (71140), perylene scarlet (71137) (perylene pigment),
Examples include isoindolinone yellow (isoindolinone pigment), quinacridone red Y (46500), and quinacridone magenta (73915). Dyes include nitroso dyes, nitro dyes, and azo dyes (mono,
(bis, tris, tetrakisazo dyes), stilbenzoa dyes, ketimine (diphenylmethane) dyes, triphenylmethane dyes, xanthene dyes,
Acridine dyes, quinoline dyes, methine/polymethine dyes, thiazole dyes, indamine/indophenol dyes, azine dyes, oxazine dyes,
Examples include thiazine dyes, sulfur dyes, aminoketone/oxyketone dyes, anthraquinone dyes, indigoid dyes, and phthalocyanine dyes. To give more specific examples, the nitroso dye is Mordant Green 4 (CI10005, hereinafter CI numbers are shown in brackets), the nitro dye is Disperse Yellow 14 (10340), and the azo dye is Direct Red 28 (22120). ), Direct Orange 71 (40205) as a stilbene azo dye,
Ketoimine (diphenylmethane) dye is Basic Yellow 2 (41000), triphenylmethane dye is Basic Blue 1 (42025), xanthene dye is Acid Dred 52 (45100),
Basic Orange 23 is an acridine dye.
(46075), Acid Yellow 2 (47010) as a quinoline dye, Disperse Yellow 31 (48000) as a methine/polymethine dye, Direct Yellow 59 (49000) as a thiazole dye, and Solvent Blue as an indamine/indophenol dye. 22 (49705), Acid Blue 59 (50315) as an azine dye, Modern Blue 10 (51030) as an oxazine dye, Basic Blue 9 (52015) as a thiazine dye, and Acid Blue 59 (50315) as an oxazine dye.
Battled 33 as an oxyketone dye
(56050), an anthraquinone dye such as Acid Blue 45 (63010), an indigoid dye such as Vat Blue 41 (73040), and a phthalocyanine dye such as Direct Blue 86 (74180). Inorganic pigments include oxides, sulfides, selenides, ferrocyanides, chromates, silicates,
Examples include phosphates. To give a more specific example, examples of oxides include red iron (C.
I.77491), CI No. is shown below), cobalt blue (77346), red lead (77578), cobalt green, chromium oxide (77288), cerulean blue (77368), viridian (77289), and yellow oxide Iron (77492), sulfides include cadmium yellow (77199), silver vermilion (77766), selenides include Prussian blue (77510 and 77520), and chromates include chrome yellow (77600) and chrome vermilion (77605). , zinc chromate (77955), barium chromate (77955), silicates such as ultramarine (77007), and phosphates such as cobalt violet deep (77360) and manganese violet (77742). As the thermofusible substance, paraffin wax, carnauba wax, montan wax, polyethylene wax, synthetic wax, solid fatty acid, solid amide, etc. having a melting point of 50 to 150°C are used. Furthermore, in the above ink layer, petroleum resin, polyvinyl acetate, polystyrene, styrene-
Thermoplastic polymeric substances such as butadiene copolymers, cellulose ethers, cellulose esters, and acrylic resins, oily substances such as mineral oils, animal oils, and vegetable oils, and plasticizers can also be added as softeners. A heat-melting ink containing the above components is applied to a transfer sheet base material. As a transfer sheet base material, the thickness is 3 to 25μ and the density is 0.9.
~1.4 g/m ³ of plastic film (polyester, polyimide, cellophane, etc.) or paper (condenser paper, synthetic paper, laminated paper, etc.) is used. The ink is applied by general hot melt coating or solvent coating, but it is also possible to apply it as an aqueous coating liquid. Further, as the image receiving sheet, paper, plastic film, synthetic paper, etc. can be used. In the thermal transfer type recording sheet of the present invention described above, since the heat-melting ink contains an ultraviolet absorber and/or an antioxidant, a transferred image with extremely excellent light resistance can be obtained. Examples will be shown below to more specifically explain the present invention, but the present invention is of course not limited to these. In addition, parts in the examples indicate parts by weight. (E) Examples Example 1 Yellow, magenta and cyan inks having the compositions shown in Table 1 were prepared. These inks have a thickness of 13μ and a density of 0.90g/cm ³
4.0 with a hot melt coater on condenser paper.
g/m ² was applied to obtain a transfer sheet. Plain paper with a basis weight of 55 g/m ² was used as the image receiving sheet. The ink layer surface of the transfer sheet and the image receiving sheet were overlapped, and three colors of yellow, magenta, and cyan were printed from the back side of the transfer sheet using a facsimile tester manufactured by Matsushita Electronic Components with a pulse width of 2.0 msec. and a voltage of 16.0 V. .

[Table] Example 2 A transfer sheet was prepared in the same manner as in Example 1, using 2-hydroxy-4-methoxybenzophenone instead of p-tert.-butylphenyl salicylate in Example 1. , printed. Example 3 The same procedure as in Example 1 was carried out using 15 parts of 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole in place of p-tert.-butylphenyl salicylate in Example 1. A transfer sheet was prepared according to the procedure and printing was performed. Example 4 In place of p-tert.-butylphenyl salicylate in Example 1, 2,6-di-tert.-butyl-p-
An image receiving sheet was prepared using cresol in the same manner as in Example 1, and printing was performed. Comparative Example 1 Yellow, magenta and cyan inks having the compositions shown in Table 2 were prepared. A transfer sheet was prepared using the same procedure as in Example 1, and printing was performed. The printed sample obtained as above was left under sunlight and in a xenon long life fade meter HAL-25X-HCL manufactured by Suga Test Instruments Co., Ltd., and changes in reflection density over time were measured using a Macbeth densitometer. . The residual rate of reflection density was calculated from the following formula.

[Table] Residual rate = Reflection density after leaving / Reflection density immediately after printing x 10
0 In other words, if the residual rate is less than 100%, fading will occur.
A value of 100% or more indicates black discoloration. The measurement results are shown in Table 3. This clearly shows that the recorded images of the present invention have excellent storage stability.

【table】

[Table] Example 5 p-tert.-butylphenyl salicylate of Example 1 (Sumisorb-90 (Sumitomo Chemical), melting point 62-64
℃) instead of 2-(2'-hydroxy-3'-tert.-
Butyl-5'-methylphenyl)-5-chlorobenzotriazole (Sumisorb-300 (Sumitomo Chemical),
(melting point: 140° C.), a transfer sheet was prepared in the same manner as in Example 1, and printing was performed. Example 6 p-tert.-butylphenyl salicylate of Example 1 (Sumisorb-90 (Sumitomo Chemical), melting point 62-64
℃), using 40 parts of 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole (Sumisorb-510 (Sumitomo Chemical), melting point 70℃ or higher),
Thereafter, a transfer sheet was prepared in the same manner as in Example 1, and printing was performed. Example 7 p-tert.-butylphenyl salicylate of Example 1 (Sumisorb-90 (Sumitomo Chemical), melting point 62-64
A transfer sheet was prepared and printed in the same manner as in Example 1, except that the amount of (°C) added was changed from 10 parts to 1 part. Comparative Example 2 p-tert.-butylphenyl salicylate of Example 1 (Sumisorb-90 (Sumitomo Chemical), melting point 62-64
4,4'-butylidene, -bis-(3-
Using methyl-6-tert.-butylphenol (Sumilizer BBM (Sumitomo Chemical), melting point 205°C or higher), a transfer sheet was prepared and printed in the same manner as in Example 1. Comparative Example 3 p-tert.-butylphenyl salicylate of Example 1 (Sumisorb-90 (Sumitomo Chemical), melting point 62-64
A transfer sheet was prepared and printed in the same manner as in Example 1, using phenyl salicylate (Zalor (Down Chemical), melting point (42 to 43°C)) instead of 3°C. Comparative Example 4 p-tert.-butylphenyl salicylate of Example 1 (Sumisorb-90 (Sumitomo Chemical), melting point 62-64
℃), using 50 parts of 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole (Sumisorb-510 (Sumitomo Chemical), melting point 70℃ or higher),
Thereafter, a transfer sheet was prepared in the same manner as in Example 1, and printing was performed. The printed sample obtained as above was left under sunlight and in a xenon long life fade meter HAL-25X-HCL manufactured by Suga Test Instruments Co., Ltd., and changes in reflection density over time were measured using a Macbeth densitometer. . The residual rate of reflection density was calculated from the following formula. Remaining rate = Reflection density after leaving / Reflection density immediately after printing x 10
0 In other words, if the residual rate is less than 100%, fading will occur.
A value of 100% or more indicates black discoloration. If the survival rate is 85% or more, there is no noticeable difference in appearance and there is virtually no problem. The measurement results are shown in Table 4. From this, Example 5
7 and Comparative Examples 2 and 4 are all found to have excellent storage stability of recorded images. However, in Comparative Example 2, since an antioxidant with a high melting point was added to the ink, the thermal transfer efficiency deteriorated and the reflection density of the image was low. Furthermore, in Comparative Example 4, the amount of ultraviolet absorber added was too large, and the reflection density was not achieved. Comparative Example 3 was excellent in both reflection density and image storage stability, but when the transfer sheet was wound up and left for one day at 50°C, blocking occurred and the ink layer adhered to the back surface of the transfer sheet.

[Table] (F) Effects of the invention Images recorded using the transfer sheet of the present invention have significantly improved storage stability compared to those recorded using conventional transfer sheets, and are suitable for color melt-type thermal transfer. The present invention has extremely high industrial significance in further enhancing the advantages of recording.

Claims (1)

[Claims] 1. In a thermal transfer recording material consisting of a transfer sheet having a heat-melting ink layer on one side of a base material that can be transferred when heated, and an image-receiving sheet that receives an image transferred from the transfer sheet, organic pigments and dyes are The heat-melting ink layer containing at least one of the above contains an ultraviolet absorber and/or an antioxidant with a melting point of 50°C to 150°C in an amount of 10 to 400% by weight based on the organic pigment and dye. Features of thermal transfer recording material.