JPS60183189A - Thermal transfer medium - Google Patents

Abstract

PURPOSE:To obtain high-density images, by constituting the titled medium of a transfer sheet provided with a transfer layer comprising a leuco dye as a main constituent, a non-cellulosic heat-fusible resin having a melting point of not higher than 150 deg.C and a cellulosic resin and a sheet provided with a receiving layer. CONSTITUTION:The thermal transfer medium is constituted of the transfer sheet provided with the transfer layer comprising a leuco dye as a main constituent, a non-cellulosic heat-fusible resin having a melting point of not higher than 150 deg.C and a cellulosic resin on a base and the receiving sheet provided with the receiving layer comprising a color developer for said leuco dye as a main constituent. Thermal transfer can be performed by laminating the transfer sheet and the receiving sheet on each other, followed by heating. The heat-fusible resin may be polyethylene, an acrylic resin, a polyamide or the like, and the cellulosic resin may be cellulose acetate, ethyl cellulose, nitrocellulose or the like.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a thermal transfer medium that utilizes a color reaction between a leuco dye and a color developer. Furthermore, the present invention relates to a thermal transfer medium that provides a transferred image with uniform density even after multiple transfers.

[Prior art]

Conventionally, thermal transfer media include those consisting of a transfer sheet with a heat-sublimable dye layer provided on a support and a receiving sheet that receives a sublimable dye image by thermal printing from the back side of the sheet, or a heat-fusible material. A combination of a transfer sheet with a pigment or dye transfer layer on a support and a receptor sheet is known.
The former one.

Due to the use of heat-sublimable dyes, dye images on receiver sheets 1 to 2 have poor shelf life, require an overcoat to be applied over the transferred image, and the latter are dyed in a heat-fusible material. Since it is a transfer layer with pigments or dyes dispersed in it, if a large amount of pigment is included in order to obtain a high-density image, the transfer efficiency will be low, making it difficult to obtain a high-density image, and it will also increase the heat sensitivity. If a large amount of thermofusible material is used, a large amount of the thermofusible material will migrate to the receiving sheet 1- side, so when separating the transfer sheet 1- and the receiving sheet, it will not be possible to peel it off smoothly. The image of fine lines becomes unclear.

In addition, since the transfer sheet 1- is colored, the receiving sheet 1-
There is a drawback that if the film is strongly pressed against the film, coloring will occur even in non-image areas.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal transfer medium that provides a stable transferred image with high density by using a small amount of thermal energy, and also provides a uniform image density even after multiple transfers.

[Measures]

According to the present invention, the first invention includes a transfer sheet having a transfer layer containing a leuco dye as a main component, and a receiving sheet having a receiving layer containing a color developer for the leuco dye as a main component, A second invention provides a heat-sensitive transfer medium characterized in that the transfer layer contains a non-cellulose thermofusible resin with a melting point of 150° C. or less and a cellulose resin, and as a second invention, The first transfer layer comprises a transfer sheet 1-, in which a second transfer layer containing a color developer for the leuco dye as a main component is provided on the same or a different support, and a receiving sheet 1-; A heat-sensitive transfer medium is provided, wherein the layer and the second transfer layer contain a non-cellulose thermofusible resin having a melting point of 150° C. or lower and a cellulose resin.

In the present invention, the transfer layer contains a non-cellulose thermofusible resin (hereinafter simply referred to as thermofusible resin) having a melting point of 150° C. or lower and a cellulose resin.

By using both of these resins, it is possible to obtain a transfer layer that has excellent thermal sensitivity, excellent mechanical strength, and excellent blocking and abrasion resistance. The transfer layer using both resins together is
It has excellent uniformity and provides a colored image with uniform density, as well as
It has the advantage of not causing image stains.

Examples of the hot-melt resin used in the present invention include polyethylene, polypropylene, polystyrene, petroleum resin, acrylic resin, vinyl chloride resin, vinyl acetate resin, vinylidene chloride resin, polyamide, polyacetal, polycarbonate, polyester, silicone resin, and phenol. Examples include resins and epoxy resins. In the case of the present invention, the hot-melt resin is.

It is preferable to use one having a melting point of 150°C or less, particularly in the range of 60 to 130°C. On the other hand, in the present invention,
Examples of the cellulose resin used in combination with the hot melt resin include cellulose acetate, ethyl cellulose, nitrocetyl cellulose, levoxymethyl cellulose, cellulose propionate, hydroxypropyl cellulose, methyl cellulose, ethyl hydroxyethyl cellulose, and cellulose acetate butylene. There are cellulose acetate 1-, cellulose acetate 1-, and cellulose acetate. In the present invention,
When the transfer layer contains a leuco dye, the proportion of the resin to be added to the transfer layer is 0.00 parts by weight per 1 part by weight of the leuco dye.
01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, and when the transfer layer contains a color developer, 0.01 to 1 part by weight, preferably 0.05 to 1 part by weight of the color developer. ~0.5 parts by weight. Further, the cellulose resin is preferably used in a proportion of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, per 1 part by weight of the thermofusible resin.

In the thermal transfer medium of the present invention, each transfer layer may contain a porous filler so that a uniformly colored image can be obtained when the same transfer sheet 1 is used many times. The porous filler used at this time has an oil absorption of at least 50mQ/100g, 1B or 15Q/l.
oog or higher is better. The proportion of the porous filler contained in the transfer layer is 0.01 to 1 part by weight, preferably 0.03 to 0.5 part by weight, per 1 part by weight of the leuco dye or color developer. Specific examples of porous fillers include inorganic acid and organic fine powders such as silica, aluminum silicate, alumina, aluminum hydroxide, magnesium hydroxide, urea-formalin resin, and styrene resin.

In addition, the transfer layer has a melting point of 200°C or lower, preferably 15°C.
It is also possible to add various thermofusible substances below 0°C.

In addition, when a receptor sheet having a receptor layer containing a color developer is used, this receptor layer may also contain the porous filler and various thermofusible materials having a melting point of 200°C or lower, preferably 150°C or lower. It can contain substances.

As the leuco dye used in the present invention, any of those conventionally used for pressure-sensitive paper and thermal paper can be applied, including triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based dyes. Preferably applied. 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)phthalide, 3 -cyclohexylamino-6-chlorofluorane.

3-dimethylamino-5,7-dimethylfluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 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-(m71~lichloromethylanilino)fluoran, 3-diethylamino-7-( 0-chloroanilino) fluorane.

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-'l-anilinofluorane, 3-(N,N-diethylamino)-5-methyl-7-(
N.

N-dibenzylamino)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrillospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrillospirane, 3-(2'- Hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5 '-21 ~ phenyl) phthalide.

3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-( 2'-hydroxy-4'-chloro-5'
-methylphenyl)phthalide.

The color developer used in the present invention includes an electron-accepting substance,
For example, phenolic substances, organic acids, salts or esters thereof, etc. are used, and from the viewpoint of practicality, those with a melting point of 200° C. or lower are preferably used. 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, ert-butylphenol (98), 4-hydroxydiphenyl ether (84), l-naphthol (98).

2-naphthol (121), methyl-4-hydroxybenzoate (131), 4-hydroxyace1hephenone (109), 2,2'-dihydroxydiphenyl ether (79), 4-phenylphenol (166),
4-bert, -octylcatechol (109),
2,2'-dihydroxydiphenyl (103), 4.
4'-methylenebisphenol (1,60), 2,2
'-methylenebis(4-chlorophenol)'(Ic
;<),2,2'-methylenebis(4-methyl-6-
SherL, -butylphenol) (125), 4,4'
-isopropylidenediphenol (1,56), 4
．． 4'-isopropylidene bis(2-chlorophenol) (90), /1.4'-isopropylidene bis(
2,6-dibromophenol) (172), 4,4'
-isopropylidene bis(2-1; erL-butylphenol) (11,0), 4,4' -isopropylidene bis(2-methylphenol) (136), 4.4'
-isopropylidene bis(2,6-dimethylphenol) (lG8), 4. '/I' -5ee-butylidene di7er/-ol (+19), /1.4' -5ec-butylidene bis(2-methyl ester) (142), 4.4
'-Cyclohexylidene diphenol (180), 4
, 4'-Cyclohexylidenebis(2-methylphenol) (184), salicylic acid (1G+(), salicylic acid meth-1-lyl ester (74), salicylic acid phenacyl ester (110), 4-hydroxybenzoic acid methyl ester (1, 31), 4-hydroxybenzoic acid ethyl ester <1.16), 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 (178), 4-hydroxybenzoic acid benzyl ester (111), 4-hydroxybenzoic acid cyclohexyl ester (1,19), 5-hydroxysalicyl M (200), 5-chlorsalicylic acid (172), 3-
Chlorsalicylic acid (178), Thiosalicylic acid (164)
), 2-chloro-5-nitrobenzoic acid (165), 4-
Methoxyphenol (53), 2-hydroxybenzyl alcohol (87), 2,5-dimethylphenol (7
5), benzoic acid (122), or-I toluic acid (10
7), metatoluic acid (111), paratoluic acid (1
81), orthochlorobenzoic acid (142), metaoxybenzoic acid (200), 2,4-dihydroxyace1-phenone (97), resorcinol monobenzoate (
135), 4-hydroxybenzophenone (133),
2,4-dihydroxybenzophenone (144), 2-
Nano 1-Itsuku acid (184), ■-Hydroxy-2-naphthoic acid (195), ethyl 3,4-dihydroxybenzoate/1.7-l (128),
3,4-dihydroxybenzoic acid phenyl ester (18
9), 4-hydroxypropiophenone (150), salicyl salicylate (14B), phthalic acid monobenzyl ester (107), 1.1-bis(4'-hydroxyphenyl)ethane (126), 1.1- Bis(4'-
hydroxyphenyl)propane (130), 1,1-bis(4'-hydroxyphenyl)hexane (] ],
1), 1゜1-bis(4'-hydroxyphenyl)hebutane (120), 1.1-bis(4'-hydroxyphenyl)-2-propylpentane (128),
1.1-bis(4'-hydroxyphenyl)-2-ethylhexane (87), 2,2-bis(4'-hydroxyphenyl)hebutane (101), 3.3-bis(4'
-hydroxyphenyl)hexane (155), 1.1
-bis(3'-methyl-4'-hydroxyphenyl)
Ethane (+01), 1,1-bis(3'-methyl-4'
-hydroxyphenyl)propane (94), 1,1-bis(3'-methyl-4'-hydroxyphenyl)butane (135), ■, ■-bis(3'-methyl-4'-hydroxyphenyl)pentane ( 97), ], ]-bis(
3'-methyl-4'-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-4'
-Hydroxyphenyl)hexane (104), 2.2-
Bis(3'-methyl-4'-hydroxyphenyl)4
-Methylpentane (129), ■, 1-bis(3' -
Methyl-4'-hydroxyphenyl)4-methylbutane (124), 3,3-bis(3'-methyl-4'-hydroxyphenyl)pentane (120), 3,3-bis(3'-methyl-4' -hydroxyphenyl)hexane (90), 5,5-bis(3'-methyl-4'-hydroxyphenyl)nonane (12+S), 2-(4'
-hydroxyphenyl)-2-(3'-chloro-4'
-hydroxyphenyl)propane (,'l 01 ),
2,2-bis(3'-isopropyl-4'-human d-xyphenyl)propane (97), 2,2-bis(3'
-tert-butyl-47-hydroxyphenyl)propane (1,17), 2,2-bis(3'-chloro-4
'-Hydroxyphenyl)propane (84), 2-(4
'-Hydroxy-3', 5-dimethylphenyl (
127), bis(3'-methyl-5'-ethyl-4'
-hydroxyphenyl)methane (105), 1.1-
(3'-methyl-5'-butyl-4'-hydroxyphenyl)butane (10/I), 2,2-bis(4-hydroxyphenyl)octane (83), bis(4-hydroxyphenylmercapto)meta; (ss), 1,2nibis(4-hydroxyphenylmercapto)ethane(1
73), 1,3-bis(4-hydroxyphenylmercapto)propane (82), 1.

4-bis(4-hydroxyphenylmercapto)butane (181), 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)3,5dioxa Hebutane (108), 1,8-bis(4-hydroxyphenylmercapto)3.

5-dioxaoctane (100).

In the present invention, the leuco dye layer and the color developer layer are
On a support such as paper, synthetic paper, plastic film, etc., usually 0.5 to 20 g/rrr, preferably 1 to
It is used at a ratio of about Log/rri. The resin may be applied to the support by any of solvent coating, Botmelt coating, and aqueous emulsion coating.

In the transfer sheet used in the present invention, the transfer layer provided on the surface thereof may be a so-called plain (no image) layer provided uniformly over the entire surface of the support, or may be formed in advance into a desired image form. It may be provided.

A transfer sheet with a non-image transfer layer has a layer on the surface of the support.
It can be obtained by simply applying a transfer layer forming liquid. On the other hand, for those with an image-shaped transfer layer, a transfer layer forming liquid is applied to the surface of the support in the desired image (including letters) by letterpress printing, gravure printing, etc. Obtainable.

In order to carry out the thermal transfer of the present invention, for example, when using a heat-sensitive φλ photographic body, a transfer sheet having a transfer layer containing a leuco dye and a receiving sheet having a receiving layer containing a color developer, the transfer This can be done by stacking sheets 1 to 1 and a receiving sheet and heating them. On the other hand, there is a transfer sheet in which a first transfer layer containing a leuco dye and a second transfer layer containing a color developer are provided on the same or different supports, and a receiving sheet (in this case, the receiving sheet is ordinary paper). , synthetic paper, plastic film, etc.), the first transfer layer is stacked on top of the receiving sheet 1 and heated to transfer the leuco dye onto the receiving sheet, and then the second transfer layer is stacked and heated. Alternatively, the second transfer layer is layered and heated to transfer the color developer, and then the first transfer layer is layered and heated to cause the leuco dye to undergo a transfer reaction. .

When performing thermal transfer using the thermal transfer medium of the present invention, it is possible to easily obtain a large number of copies by repeating the above operations using the same transfer sheets 1 to 1 and replacing the receiving sheets one after another. can. In addition, when obtaining a multicolor copy, use a transfer sheet having a plurality of transfer layers that develop colors in different tones, and combine the transfer layer of the desired tone with the receiving sheet 1 to carry out the transfer operation. All you have to do is

〔effect〕

In the present invention, the leuco dye and the color developer are supported separately on separate supports or even on the same support, so that the leuco dye and the color developer are supported separately, so that the leuco dye and the color developer are supported separately, so that the leuco dye and the color developer are supported separately. There is no problem of color fog, and furthermore, since the resulting copy does not contain a combination of leuco dye and color developer in the non-image area, no color develops even when heated. Does not occur. In addition, since it has high thermal sensitivity, high density images can be obtained with a small amount of heating energy, and it is also economical because a large number of copies can be made using the same transfer sheet 1-. Moreover, in the case of the present invention, since the transfer layer contains a special resin, the transfer layer has good mechanical strength and heat resistance, and also has excellent heat sensitivity.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (1) Creation of transfer sheet 1-(A-1) 3-N-Methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane 10 g Styrene resin (melting point 75°C) 2 g Ethyl cellulose 2 g A composition of 100 g of methyl ethyl ketone was applied to the surface of a 6 μm thick polyester film using a wire bar and dried to give a coating weight of 4 g/
rr! A transfer sheet (A-1) was prepared.

(2) Preparation of receptor sheet 1-(B-1) 4-hydroxybenzoic acid n-butyl ester 20g silica fine particles (oil absorption 200m Q /Long) 'Lo
After dispersing a composition consisting of 100 g of polyvinyl alcohol and 100 g of water using a ball mill for 24 hours, using a wire bar, it was dispersed using high-quality paper (basis weight 35 g/+r).
r) and dried to prepare a receptor sheet (B-1) with a coating weight of 5 g/rrr.

The receptor sheet (B-1) was brought into contact with the surface of the transfer sheet (A-1) obtained in this way, and the transfer sheet (8-1)
) was applied with heating energy of mJ using a thermal head from the back side of the sample, and the above operation was repeated 10 times. The image density was 1.15. In addition, after conducting an observation test using a lab tester to roll the transfer layer of the transfer sheet 50 times with a weight of 500 g, 1 mJ of heating energy was applied to the back side of the transfer sheets 1 to 1 with a thermal head. 1.19 was obtained, and no decrease in concentration was observed. Furthermore, when 50 transfer sheets (A-1) were stacked in an oven at 60°C and stored for 24 hours, blocking of the transfer layer did not occur, and a thermal head was applied to the back side of transfer sheet 1-1.
When mJ of heating energy was applied, the image density was 1.17.
was gotten.

Comparative Example 1 A transfer sheet (A-2) was prepared in the same manner as in Example 1, except that ethyl cellulose was not added to transfer sheet 1, and the same operations as in Example 1 were performed. As a result, a high-density image was obtained with an image density of 1.25 in the first run, but the image density after the rub-off test was 0.74, and the mechanical strength of the comparative product was inferior to that of the inventive product. was. When 50 more sheets were stacked and stored in an oven at 60° C. for 24 hours, the transfer layer developed blocking.

Comparative Example 2 A transfer sheet (^-3) was prepared in the same manner as in Example 1 except that the styrene resin in the transfer sheet was removed, and the same operations as in Example 1 were performed. As a result, the first image density was 0.86. The image density after the rub-off test was 0.84, and no blocking occurred even when stored in an oven at 60° C. for 24 hours, and the image density was 0.88.

The following table summarizes the following.

Table-1 As described above, the product of the present invention (^-1) is a transfer sheet that has excellent mechanical strength and heat resistance, and can produce high-density images.

Example 2 (1) Creation of transfer sheet (A-4) 3-diethylamino-6-chlorofluorane 15 g'polyester resin (melting point 60°C) 1 g cellulose acetate
Four fish were dissolved in 100 g of methyl ethyl ketone, coated on a 6 μm thick polyester film using a wire bar and dried, with a coating weight of 1 g #+? A transfer sheet (A-/I) was prepared.

(2) Preparation of Transfer Sheet (A-5) 1.3~Bis4-Hydroxyphenylmercap 1~) A composition consisting of 25° propane, 2 g petroleum resin (melting point IOO°C), and 3 g methylcellose was prepared using a ball mill for 24 hours. After being dispersed for a time, it was coated on a 6 μm thick polyester film using a wire bar and dried.
A-5) was created.

Plain paper was brought into contact with the surface of the transfer sheet (A-4) thus obtained, and IJ heating energy was applied from the back surface of the transfer sheet (A-4) using a thermal head. Next, bring the front surface of the transfer sheet (A-5) into contact with the same spot, and start from the back surface of the transfer sheet (^-5).

When 1 mJ of heating energy was applied by the thermal head, a clear red image with an image density of 1.15 was obtained on plain paper. Note that no stains were observed in the non-image areas on the plain paper. Furthermore, transfer sheets 1 to 8-4 and A-5 had good mechanical strength and heat resistance.

Example 3 A composition consisting of crystal violet lactone, 15 g of silica fine particles (oil absorption: 30 (1 m Q /100 g), 1 g of polyester resin (melting point: 61°C), 2 g of ethyl cellulose, 3 G of methyl ethyl kene, 1-loog) was dispersed for 24 hours using a ball mill, and then dispersed using a wire bar. A transfer sheet with an adhesion amount of 4 g/n was prepared by coating and drying it on a 10 μ thick capacitor paper using the following method.

This transfer sheet was brought into contact with the receiving sheet used in Example 1, and the same operation as in Example 1 was performed by applying 1 mJ of heating energy from a thermal head. As a result, the image density for the first time is 1.12, and the image density for the tenth time is 1.10.
The image density after the love test was 1.10. Furthermore, the image density after being stored in an oven at 60° C. for 24 hours was 1.11.

Patent applicant Rico Co., Ltd. Representative Patent Attorney Toshiaki Ikeura

Claims (2)

[Claims] (1) Consisting of a transfer sheet having a transfer layer containing a leuco dye as a main component, and a receiving sheet 1 having a receiving layer containing a color developer as a main component for the leuco dye, the transfer layer has a melting point of 150°C or less. A heat-sensitive transfer medium characterized by containing a non-cellulose heat-melting resin and a cellulose resin. (2) A thermal transfer sheet in which a first transfer layer containing a leuco dye as a main component and a second transfer layer containing a color developer for the leuco dye as a main component are provided on the same or separate supports, and a receiving sheet 1 ~
The first transfer layer and the second transfer layer have a melting point of 50
1. A thermal transfer medium characterized by containing a non-cellulose heat rIJ melting resin at a temperature of °C or less and a cellulose resin.