JPS62184885A - Thermal transfer medium - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer medium capable of giving transferred images having high density, excellent uniformity, abrasion resistance and light resistance and showing absorbance in a near infrared region, by incorporating a metal complex dye and/or a metal complex salt dye into a transfer layer. CONSTITUTION:A metal complex dye and/or a metal complex salt dye is incorporated into a transfer layer, in a thermal transfer medium comprising a transfer sheet which comprises the transfer layer comprising a leuco dye on a base and a receiving sheet which comprises a receiving layer comprising a color developer for the leuco dye as a main constituent on a base. The amount of the metal complex dye and/or the metal complex salt dye is suitably 0.03-3 pts.wt. per 1 pts.wt. of the leuco dye. If the amount of the metal complex dye and/or the metal complex salt dye is less than 0.03 pts.wt., a light fading effect on images is poor, and the images turn red under the action of light. If the amount is more than 3 pts.wt., a eutectic effect on the leuco dye and the color developer is low, and uniformity of images is poor. The total amount of the leuco dye and the metal complex dye and/or metal complex salt dye used on the base is ordinarily about 0.3-30 g/cm<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a thermal transfer medium that utilizes a color-forming reaction between a leuco dye and a color developer.

[Prior art]

Conventionally, thermal transfer media include those consisting of a transfer sheet on which a heat-sublimable dye is provided on a support, and a receiving sheet 1 that receives a heat-sublimable dye image by thermal printing from the back side of the sheet I, and a paraffin-based transfer sheet. A combination of a transfer sheet and a receiving sheet is known, in which a transfer layer of a heat-fusible substance such as wax and a pigment or dye is provided on a support, and the key to the former is that it uses a heat-sublimable dye. However, the dye image on the receiving sheet has poor storage stability, an overcoat must be applied on the transferred image, and there is no absorption ability in the near-infrared region. In addition, the latter method has a disadvantage in that the paraffin used as the thermofusible material has low mechanical strength, so that the abrasion resistance due to rubbing of the transferred image is poor.
``On the other hand, there are also known thermal transfer media in which substances that react with each other to develop color due to heat are supported on separate supports, and these support layers are brought into opposing contact to perform thermal printing.
If this type of material has high heat sensitivity and is exposed to light for a long period of time, the color tone will change from black to red. Moreover, those with excellent light resistance have the disadvantage of low thermal sensitivity.

〔the purpose〕

An object of the present invention is to provide a heat-sensitive transfer medium that can obtain images with high density and excellent uniformity, has excellent abrasion resistance and light resistance, and has absorption ability in the near-infrared region. With the goal.

〔composition〕

According to the present invention, a photosensitive material comprising a transfer sheet having a transfer layer containing a leuco dye provided on a support, and a receiving sheet having a receiving layer containing a color developer as a main component for the leuco dye provided on a support. The present invention provides a thermal transfer medium characterized in that the transfer layer contains a metal complex dye and/or a gold r7 complex dye.

In the thermal transfer medium of the present invention, a receiving sheet is stacked on a transfer sheet so that its receiving layer is in contact with the transfer layer of the transfer sheet, and a desired image is printed on the surface of the receiving sheet by thermal printing from the back side of the transfer sheet or the back side of the receiving sheet. A colored image is formed. In this case, since there is a layer on the surface of the receiving sheet whose main component is a color developer that is eutectic with the leuco dye, the transfer layer is easily transferred and the image uniformity is improved. In addition, in the present invention,
By mixing metal complex dyes and/or metal complex salt dyes, which have better light resistance than general organic dyes, with leuco dyes, it is possible to obtain transferred images with less color change even when exposed to sunlight, etc., and also to resist friction. A strong image can be obtained.

The ratio of the leuco dye to the metal complex dye and/or metal complex salt dye is 0.03 to 3 parts by weight, preferably 0.05 to 1 part by weight, per 1 part by weight of the leuco dye. It is appropriate to make it a department. The amount of metal complex dye and/or metal complex salt dye used is 0.0
If it is less than 3 parts by weight, the photofading effect of the image will be poor and the image will change due to light, and if it exceeds 3 parts by weight, the eutectic effect of the leuco dye and color developer will be small, resulting in poor image uniformity. Become.

The metal complex dye used in the present invention refers to a dye in which a negative group is coordinated around the atom or ion of a metal or a totally analogous element, and the metal complex dye refers to a dye that is a salt containing a complex ion. .

Specific examples of these dyes are shown below.

(Color Index Number)Solven
t Yellow 162〃〃79 〃〃32 〃〃19 〃〃81 〃〃21 Solvent Yellow 82Solvent
Orange 45N pt 55 〃〃54 〃〃70 Solvcn7Brown 37〃〃58 Solvent Red 122n n
1Q9 II n 119 〃〃160 n II 122 〃〃118 〃〃35 Solvent Violet, 2Solve
nt, Blue 25〃〃70 Solvent, Black 34〃〃27 〃〃47 Acid Yellow 98 Acid Red 179 Acjd Violet 56Acid
Grccn 35 ^Cid Orange 74 Acid Red 184 Acid Black 43 Acid Green 45 Acid Blue 161 Acid Black 52 Direct, [1rotyn 173Dir
oct, Blue 150Direct,
Violet 79Direct, Brown
167 Direct Blue 158 Direct Red 180 Direct, Blue 149 Direct
Yellow 33 Direct, Violet
81〃〃80 Direct, Rad 173Direct,
Orange 96Direct Blue8
4 Direct Brown 95Dire
ct, Blue 93Direct, Gray
en 36〃〃23 Direct: Black 71Direct
t, [31own 100Direct Vio
let, 48Direct, Red 8
3 Direct violae 47 The transfer sheet in the present invention is a support, for example.

For the surface of paper, synthetic paper, especially plastic film,
A transfer layer containing a leuco dye and the metal complex dye and/or metal complex salt dye as a main component is provided. In this case, any leuco dye that has traditionally been used for pressure-sensitive paper or thermal paper can be used, and triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based dyes are preferably used. be done. Specific examples of these leuco dyes are shown below.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(P- dimethylaminophenyl)-6-diethylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl) Watari 3
-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylflurane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-
6-Methyl-7-chlorofluorane.

3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluorane.

3-pyrrolidino-6-methyl-7-anilinofluorane, 2-(N-(3'-trifluoromethylphenyl)
amino)-6-dinithylaminofluorane.

2-(3,6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-? -(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran.

3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N,N-diethylamino )-5-methyl-7-(
N.

N-dibenzylamino)fluoran.

Benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-fromo-3'-methoxy-benzoindolino-pyrylospirane.

3-(2'-Hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide.

3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl)phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3- (2'-methoxy-51-methino;nophenyl)phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-7°-5
'-methylphenyl) phthalide.

Further, in the present invention, the total amount of the leuco dye, metal complex dye and/or metal complex dye is usually 0.3 to 30 g/d, preferably 0.5 to 5 g/d, relative to the support.
It is used at a rate of about g/rrr.

The receptor sheet used in the present invention is one in which a receptor layer containing a color developer for the leuco dye as a main component is provided directly or via an undercoat layer on a support such as Paper 1 synthetic paper or a plastic film. .

In this case, as the color developer, 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, preferably a melting point of 200
℃ or less is 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-t, Cr7-butylphenolsidiphenyl ether (84), ■ Naphthol (98
), 2-naphthol (121), methyl-4-hydroxybenzonyh (131), 4-hydroxyace1-
Phenone (109), 2,2'-dihydroxydiphenyl ether (79), 4-phenylphenol (16
6), 4 t. ert. -octylcatechol (1
09), 2,2'-dihydroxydiphenyl (10
3), 4,4'-methylenebisphenol (160)
, 2.2'-methylenebis(4-chlorophenol)
(164), 2,2'-methylenebis(4-methyl-
6-Crt-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-ter-monobutylphenol) (110), 4,4'-isopropylidene bis(2-methylphenol) (136), 4, 4'-isopropylidene bis(2,6-dimethylphenol)
(168), 4.4'-sec-butylidene diphenol (119), 4.4'-sec-butylidene bis(2-methylphenol) (142), 4.4'-
Cyclohexylidene diphenol (180), /1.
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
78), 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 ( 87), 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), l-hydroxy-2-naphthoic acid (195), 3,4-dihydroxybenzoic acid ethyl ester (128) ), 3.4-dihydroxybenzoic acid phenyl ester (189), 4-hydroxypropiophenone (150), salicyl salicylate (14 g), phthalic acid monobenzyl ester (107
)etc.

Further, in the present invention, a thermofusible substance having a melting point of 200° C. or lower, preferably 150° C. or lower can be added to the transfer layer or the receiving layer. The amount used is 0.1 to 50 parts by weight per 1 part by weight of the color developer. The amount of solid content deposited in the receptor layer is preferably about 1 to 15 g/I.

When providing a transfer layer and a receiving layer on each support, conventional binder resins are used, such as polyvinyl alcohol, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylic Water-soluble, organic solvent-soluble or aqueous emulsion-forming materials such as acids, starch, gelatin, polystyrene, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, etc. can be used, but especially in the transfer layer. In the case of a resin having a melting point or softening point of 50 to 130°C, for example, polyethylene, polypropylene, polystyrene, petroleum resin, acrylic resin, vinyl chloride resin, vinyl acetate resin, vinylidene chloride resin.

polyvinyl alcohol, cellulose resin, polyamide,
It is preferable to use polyacetal, polycarbonate, polyester, fluororesin, silicic acid resin, natural rubber, chlorinated rubber, butadiene rubber, olefin rubber, phenol resin, urea resin, melamine resin, epoxy resin, polyimide, etc. as the binder.

Further, in the present invention, a filler may be added to the transfer layer and the receiving layer, if necessary.

In this case, the oil absorption amount is usually 50 m Q / 100 g (
(According to JIS K5101 method) or more, preferably 150
It is desirable to use a porous filler of m m /100 g or more.

Specific examples of porous fillers include inorganic and organic fine powders such as silica, aluminum silicate, alumina, aluminum hydroxide, magnesium hydroxide, urea-formalin resin, and styrene resin.

〔effect〕

Since the thermal transfer medium of the present invention has the above-mentioned structure, it is possible to obtain images with high density and excellent uniformity, as well as excellent abrasion resistance, light resistance, etc.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that both "1 part" and "1%" shown below are based on weight.

[Creation of transfer sheet 1-(Al)] 5olverrj Black 34 (total reflex complex dye)
Part 4 3-N-Methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane 161I
Polyvinyl chloride (sp value 9.7, softening point 85°C) 2II
A composition consisting of methyl ethyl ketone 100// was dispersed for 24 hours using a ball mill, and then applied onto a 6 μm thick polyester film using a wire bar and dried to obtain a transfer sheet having a transfer layer with a coating weight of 1.5 g/rf. (AI) was created.

[Creation of reception sheet (B)]

4-hydroxybenzoic acid n-butyl ester 20 parts polyvinyl alcohol 3 n water
100/
After dispersing the combination consisting of
5 g/rri
A receptive sheet (B-1) having a receptive layer was prepared.

[Creation of transfer sheet (A2)] 5olvent of transfer sheet (A1), 34 parts of Black, 3-N-methyl-N-cyclohexylamino-
A transfer sheet (A
2) was created.

[Creation of transfer sheet (A3)] 5olvent B1ack34 of transfer sheet (AI)
8 parts of 3-N-methyl-N-cyclohexylamino-
A transfer sheet (A
3) was created.

[Creation of transfer sheet (A4)] Transfer sheet (At) 5olvent B1ack3/
A transfer sheet (At) was prepared in the same manner as Transfer Sheet 1-(At) except that 15 parts of I and 5 parts of 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane were used.
A4) was created.

[Creation of transfer sheet (A5)] Transfer sheet (At) 5olvent, Black3
A transfer sheet (A5) was prepared in the same manner except that 4 was omitted and 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane was changed to 20 parts.

[Creation of transfer sheet (86)] 5olvent of transfer sheet (A1), Black
Transfer sheet (A6) was prepared in the same manner as transfer sheet (A1) except that 20 parts of 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane was omitted.
It was created.

[Preparation of transfer sheet (A7)] A transfer sheet (A7) was prepared in the same manner as transfer sheet (A1) except that the composition of the transfer sheet (Al) was changed to the following composition.

Carbon black 18 parts Carnauba wax 10 Paraffin wax (melting point 97°C) '13n ethylene-vinyl acetate copolymer 3 tt Cacaon
The transfer sheet and receiving sheet obtained as described above were combined as shown in Table 1, the transfer sheet and receiving sheet were overlapped, and 1 mJ of heating energy was applied from the back side of the transfer sheet using a thermal head. , a black image was obtained. The image was subjected to the following tests.

(1) Image density measurement: Macbeth Densitometer RD514 (2)
Image uniformity: Expressed by reading with a barcode reader. (Number of readings per 100 scans) (3) Abrasion resistance: The image was rubbed with cardboard 100 times under a load of 20 g/cnf, and the images after the test were visually ranked.

(4) Light resistance: Fade meter (Toyo Rika 10 > 1
Light was irradiated for 2 hours, and the color tone change was visually observed.

Table 1 (Note 2) *: For Comparative Example 3, the readability with a barcode reader decreased from 100 to 20 after the abrasion resistance test.

Claims (1)

[Claims] (1) In a heat-sensitive transfer medium comprising a transfer sheet having a transfer layer containing a leuco dye on a support, and a receiving sheet having a support layer having a receptor layer containing a color developer for the leuco dye as a main component. A heat-sensitive transfer medium, characterized in that the transfer layer contains a metal complex dye and/or a metal complex salt dye.