CA1232452A - Dye mixtures for sublimation heat-sensitive transfer recording - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A dye mixture for heat-sensitive transfer recording which comprises a dye [A] of the general formula:

wherein R25, R26 and R27 each represents C1 - C8 straight-chain or branched-chain alkyl and a dye [B] of the general formula:

Description

123~5.~

This is a divisional application of Serial Number filed July 9, 1985.
This invention relates to dye mixtures for use in sublimation heat-sensitive transfer recording.
Heretofore, techniques for color recording facsimile printers, copying machines, television images, etc. have been sought, and color recording techniques by electron photography, ink-jet process, heat-sensitive transfer, etc. have been under study.
The heat-sensitive transfer recording process is considered more advantageous as compared with other processes since the maintenance and operation of the device are easier and the device and expendable supplies are less expensive.
The heat-sensitive transfer process is roughly classified into two processes, that is, a molten heat-sensitive transfer recording process which comprises heating a transfer sheet having a heat-melting ink layer formed on a base film by a heat-sensitive head to melt said ink thereby transfer recording onto a recording body, and a sublimation heat-sensitive transfer recording process which comprises heating a transfer sheet having an ink layer containing a I

sublimable dye formed on a base film to sublime the dye thereby transfer recording onto a recording body.
And, said sublimation heat-sensitive transfer recording process is believed suitable for full color recording since it is possible to control the amount of the dye to be sublimed and transferred by controlling the energy applied to the heat-sensitive head and hence gradation expression is easy.
In general, full color recording is conducted by using tricolor dyes, that is, a cyan color dye, a magenta dye and a yellow color dye, and sometimes, four color dyes, that is, these three plus a black color dye, but in order to obtain full color recording having good color reproducibly-try, the following requirements must be satisfied: the no-spective dyes easily sublime under the operational condo-lions of the heat-sensitive recording head, do not undergo thermal decomposition under the operational conditions of the heat-sensitive recording head, have preferred hues for color reproduction, have great molecular absorption co-efficient, are stable against light, moisture, chemicals, etc., are easily synthesized, have excellent adaptability to inks, etc.
However, no conventional cyan dye has satisfied the above requirements.
Accordingly, this invention aims to provide cyan ~23; it .
color dye mixtures which fulfill such requirements that they easily sublime under the operational conditions of the heat-sensitive recording head, do not undergo thermal decompose-lion under the operational conditions of the heat-sensitive recording head, are stable against light, are easily Cynthia-sized are readily and uniformly dissolved or dispersed to prepare an ink of a high concentration, etc.

The present invention provides a dye mixture for heat-sensitive transfer recording which comprises a dye [A] of the general formula [X]:

NHCOR

one N<R27 [X]

: wherein R 5, R and R27 each represents Of - C8 straight-chain or branched-chain alkyd and a dye By of the general lo formula [XI]:

O N N < [XIj SHEA

I

wherein R , R 9 and R each represents Of - C8 each represents straight-chain or branched-chain alkyd.
The present invention also provides a method of sublimation heat-sensitive transfer recording, which method comprises heating a transfer sheet having an ink layer containing a sublimable dye coated on a base film to sublime the dye thereby transfer recording onto a recording body, wherein the said dye is the dye mixture as mentioned above.
The present invention further provides a sublimation heat-sensitive transfer recording sheet, which comprises an ink layer containing a heat-sensitive sublimable dye coated on a base film, wherein the said dye is the dye mixture as mentioned above.
The present invention still further provides a process for producing a sublimation heat-sensitive transfer recording sheet, which process comprises:
a) dissolving a heat-sensitive sublimable dye in a medium or dispersing the dye in a fine particle form in a medium together with a binder to prepare an ink, and b) coating the ink on a base film and drying the coating, wherein the said sublimable dye is the dye mixture as mentioned above.
In the above general formula [X] and [XI], preferred combinations are those wherein R25 and R 8 are each Of - C4 straight-chain or branched-chain alkyd, and R , R , R 9 and R30 are each Of - C4 striation alkyd, and especially preferred is a mixture of a dye of the following structural formula: N OUCH
\ / 2 5 C2f~5 ~%~

and a dye of the following structural formula:

O by N \

2 5 SHEA

The mixing ratio (by weight) of these dyes is suitably such that the former ranges from 5 to 95% and the - pa -AYE
latter ranges from 95 to I especially preferably the former ranges from 30 to 70~ and the latter ranges from 70 to 30~.
The dyes for heat-sensitive transfer recording of the above general formula [X] and [XI] of this invention may be produced by, for example, the following process:
That is, a phenol of the following general formula [a]:

NHCOR

HO [a]

wherein -R is as defined above R25 and R28 and an aniline of the following general formula [b]:

HEN - Al by R2 6 <R2 wherein -K represents R I R

R26, R27, R29 and R30 are as defined above are heated in the presence of silver nitrate, thereby a dye mixture for heat-sensitive transfer recording of the above general formula [X] and I of this invention may be produced.
For applying the dyes for heat-sensitive transfer I

recording of the above general formula I and [XI] of this invention in the sublimation heat-sensitive transfer record-in process, the dye may be dissolved, or dispersed in a fine particle form, in a medium together with a binder to prepare an ink, then said ink is coated on a base film and dried, thereby a transfer sheet is prepared.
As the binder for the preparation of the ink, there may be used water-soluble resins such as cellulosic type, acrylic acid type, starch type, etc.; resins soluble in organic solvents, such as acrylic resins, methacrylic resins, polystyrene, polycarbonates, polysulfones, polyether sulfones, ethyl cellulose, etc.; and the like In the case of the resin soluble in organic solvents, it may by used not only as a solution in an organic solvent but also in the form of an aqueous dispersion.
Examples of the medium for the preparation of the ink include, in addition to water, organic solvents, for example, alcohols such as methyl alcohol, isopropyl alcohol, isobutyl alcohol, etc.; cello solves such as methyl cello-solve, ethyl cello solve, etc.; aromatics such as toluene,xylene, chlorobenzene, etc.; esters such as ethyl acetate, bottle acetate, etc., kittens such as acetone, methyl ethyl kitten, methyl isobutyl kitten, cyclohexanone, etc.; Shelley-fine type solvents such as ethylene chloride, chloroform, trichloroethylene, etc.; ethers such as tetrahydrofuran, Jo I Z

Dixon, etc., N,N-dimethylformamide, N-methylpyrrolidone, etc.
As the base film for coating the ink for the preparation of the transfer sheet, tissue paper such as condenser paper, glassing paper, etc. and a film of a plastic having good heat resistance, e.g., polyesters, polyamides, polyamides, etc. are suitable, and the thickness of said base film is suitably in the range of 3 to 50 em.
As the method for coating the ink on the base film, it may be conducted by using a reverse roll coaler, a Grover coaler, a rod coaler, an air doctor coaler, etc., and the thickness of the ink coated layer after drying may suitably be in the range of 0.1 to 5 em (Fuji Harazaki, published from Make Shorten in 1979, "Coating Method Where a mixture of the dyes of the above general formulae OX] and CXI] is used, since the dyes do not separate when an ink of a high concentration is prepared or the ratio to the binder is increased, it is possible to prepare a more uniformly dissolved ink at a high concentra-lion as compared with the cases where the respective dyes are used singly, and by using such an ink, a transfer sheet on which the mixed dye has been uniformly coated at a high concentration may be obtained. In addition, by using this transfer sheet, cyan color transfer recording having neither unevenness of the image nor abrasion staining may be obtain-~Z3~4~;Z

Ed This invention is more particularly described by the following examples, but it should be noted that this invent lion be not restricted by these examples.

(i) Preparation of an Ink Bonn [A ]

NHCOCH

I < LB1]
C~3 C2H5 Mixing ratio Mixed Dye [A I g (50~) : [B I g (50~) Polysulfone resin (DUEL P-1700) *10 g Chlorobenzene50 g _ Total 74 g * DUEL P-1700 tirade mark) produced by Nissan Chemical Industries, Ltd.

~2~2 The mixture of the above composition was treated by a paint conditioner for lo minutes to prepare an ink. The dye and the resin had been completely dissolved and thus it was possible to obtain an ink in a uniform solution of a high concentration.
(ii) Preparation of a Transfer Sheet The aforesaid ink was coated on a polyamide film (15 em thick) using a bar coaler (produced by OK Print Coat Instruments Co., No. l) and dried in hot air at 60C, there-lo by there was no separation of the dye and it was possible Tibetan a uniformly coated transfer sheet.
(iii) Transfer Recording The ink coated surface of the aforesaid transfer sheet was overlapped with a recording body, and recording was effected using a heat-sensitive head under the following conditions, thereby it was possible to obtain uniform brilliant cyan color recording having a high color density of 1.80 without unevenness in the image.
Recording Conditions Linear density of main scanning and minor scanning: 4 dots/mm Recording electric power: 0.6 W/dot Heating time of the head: lo m sec.
The recording body was produced by coating a liquid prepared by mixing lo g of an aqueous dispersion of 34% by weight of a saturated polyester (produced by Toy Spinning _ g _ I

Co., Ltd., VYLONAL MD-1200, trade mark) and 1 g of silica (produced by Nippon Silica Industry Co., Ltd., Nipsil EYE, trade mark) on a wood free paper sheet (200 em thick) using a bar coaler (produced by OK Print Coat Instruments Co., No.

3) and thereafter drying.
The color density was measured by using a density-meter Model ROD 514 manufactured by Macbeth Co., U.S.A.
(filter: fatten Jo. 25).
A light fastness test was conducted on the obtained recording using a carbon arc fade-o-meter (manufactured by Sugar Tester Co., Ltd.) at a black panel temperature of 63 + 2C to find that there was hardly declaration or change in color after exposure to light for 40 hours.

inks were prepared by procedures similar to those described in Example 1 except that 14 g of the mixed dye used in Example 1 was replaced by 14 g of the dye [A ] alone (Comparative Example 1) and 14 g of the dye [Blue alone (Comparative Example 2), respectively. With each ink, a part of the ink did not dissolve and thus remained undies-solved. Each ink was coated on a base film and dried, but there was remarkable separation of the dye, and thus a non-- uniform transfer sheet was merely obtained. Thereafter, transfer recording was conducted using each obtained transfer sheet, but there was only obtained cyan color transfer recording with unevenness of the image and also distinct abrasion staining.

Preparation of the ink, preparation of the transfer sheet and transfer recording were carried out according to the procedures described in Example 1 except that -the mixed dye used in Example 1 was replaced by the mixed dye set forth in Table 1, and as a result, it was possible to prepare inks of high concentrations, to obtain uniformly coated transfer sheets without separation of any ink and to obtain cyan color recording having the high color density set forth in Table 1.

~Z4~;~
.

Table 1 Mixing Color Density No. Structural Formula of the Dye Ratio of the (%) Recording O N\ 45 2 - 1 1.80 JO N No C2H5 55 SHEA __ _ _ NHCOC3H7(n) , I= b ON -N 40 2 - 2 - 1.80 ; NHCOCH3 O- N -No C2~5 60 NHCOC4Hg(n) 60 2 - 3 1.80 I= b ON N 40 , _ 12 lZ3~2 ... ..
NHcocsHll(n) O= N C Ho 70 2 - 4 _ . 1.75 C~3 _ _ NHCOCgH17(n) b C2H5 50 2 - 5 __ 1.75 b C2~5 50 SHEA _ SHEA
by C2~s 2 - 6 _ 1~80 . NHCOCH3 C2~5 50 ~%3~l5V~

2~5 2 - 7 1.80 by N 5 _ _ _ . bC4H g ( is o ) 6 0 2- 8 1.80 orb No C OH 5 . 4 0 .

. KIWI - ' _ NHCOCH2CHC4Hg (n) 2 9 b ~C2H5 70 1.75 , so --I= b ON -N 60 2 - lo 1080 b~c2~s .. .. ___ . . NHCOCH3 O ON -No SHEA 40 2 -ill 1.80 : I= b ON SHEA 60 .
SHEA

C3~7(n) 45 .
2 - 12 1.80 . NXCOCH3 I= b ON C3H7(n) 55 . C3H7(n) . SHEA

.

: - 15 ~232~L~2 . . .. .. _ . . . .

b No ,, C OH g ( n ) 5 0 2 - 13 _ 1.80 h C4Hg ( n) 5 0 : ._ _ b C2H5 40 2- I . 1.80 b 3 C H 6 0 . NHCOC OH 5 I NUN

2- 15 _ 1.8û

. . . Bonn 4 5 , I I

_ , SHEA _ NHCOCH OH
O= N -No 50 2 - 16 1.7 N OH ~C~3 NHCO
. ~_~ OH SHEA
O= ON No 40 2 - 17 SHEA 1.70 N KOCH SHEA

SHEA
,C~3 NHCOCH SHEA
I= b ON No C3H7(n) 60 C3H7~n) 2 - 18 1.70 . NHCOCH KIWI 3 O= b ON No C3H7(n) 40 C3H7(n) SHEA

_ 17 -~23~4~

.. _. . _ NHcoc3H7~n) 2 - 19 L C235 55 1.75 NHcoc3H7(n) O= b ON -No 45 NHCOC4Hg(n) b C2H5 40 - I _ _ 1.75 NHCOC4Hg(n) b No C2~5 60 SHEA .
NHCOCH3 .

. Clue 50 2 - 21 _ . 1075 ... NHCOCH3 I , Clue Shelley SHEA

. .

~Z3~

.. .

own ( ) 60 2- 22 . 1070 >=\ A C6H13 (n) I=) C6H13 ( n) 4 0 SHEA
_ .

. >=~ C8H17 (n) 45 O=< NUN
\=/ \=/ C8 H17 ( n) .

=b=N~--N~ C8H17 in) 55 CgH17 (n) KIWI
' by C2H5 25 2- 24 1~80 I

NHCOC OH 5 .
own Shea 25 orb NUN C OH 5 2 5 . .

(i) Preparation of the Ink b \ CA ]

--C C2B5 [By]
SHEA

Mixing ratio mixed ye AYE] 7 g (50%) [B ] 7 g (50~) : Cellulose acetate * 10 g Methyl ethyl kitten 50 g Total 74 g * L-30 (trade name) produced by Damsel Ltd.

The mixture of the above composition was treated by a paint conditioner for 10 minutes to prepare an ink. The dye and the resin had been completely dissolved and thus it was possible to obtain an ink in a uniform solution of a high concentration.
(ii) Preparation of a Transfer Sheet The aforesaid ink was coated on a condenser paper sheet using a bar coaler (produced by OK Print Coat Incitory-mints Co., Jo. 1) and dried in hot air at 60C, thereby there was no separation of the dye and it was possible to obtain a uniformly coated transfer sheet.
lit Transfer Recording Transfer recording was conducted according to the procedures described in Example 1 using the transfer sheet obtained above and the recording body described in Example 1, thereby it was possible to obtain uniform brilliant cyan color recording having a high color density of 1.80 without unevenness of the image.

Inks were prepared by procedures similar to those described in Example 3 except that 14 g of the mixed dye used in Example 3 was replaced by 14 g of the dye CAY] alone (Comparative Example 3) and 14 g of the dye By alone (Comparative Example 4), respectively. The obtained inks showed remarkable separation of the dye and gave non-uniform transfer sheets. Using these transfer sheets, transfer ~Z3;~

recording was conducted, but there was merely obtained cyan color transfer recording having much unevenness of the image and also distinct abrasion staining.

I) Preparation of the Ink ONE f [A ]

3 7 ( I f ~33]

.. SHEA

. Mixing ratio Mixed Dye [A ] 6 g (60%) [B ] 4 g (40%) Ethyl cellulose * 10 g Methyl ethyl kitten 50 g _ Total 70 g * Produced by Hercules, Inc.

The mixture of the above composition was treated by a paint conditioner for 10 minutes to prepare an ink. The dye and the resin had been completely dissolved and thus it was possible to obtain an ink in a uniform solution of a high concentration.
(ii) Preparation of a Transfer Sheet The aforesaid ink was coated on a condenser paper sheet using a bar coaler (produced by OK Print Coat Incitory-mints Co., No. 1) and dried in hot air at 60C, thereby there was no separation of the dye and it was possible to obtain a uniformly coated transfer sheet.
(iii) Transfer Recording Transfer recording was conducted according to the procedures described in Example 1 using the transfer sheet obtained above and the recording body described in Example 1, thereby it was possible to obtain uniform brilliant cyan color recording having a high color density of 1.70 without unevenness of the image.

Inks were prepared by procedures similar to those described in Example 4 except that 10 g of the mixed dye used in Example 4 was replaced by 10 g of the dye [A] alone (Comparative Example 5) and 10 g of the dye [B ] alone (Comparative Example 6), respectively. Each obtained ink showed remarkable separation of the ink, and the obtained ~;~3~2 sheets were non-uniform sheets. Thereafter, using these transfer sheets, transfer recording was conducted merely to obtain cyan color transfer recording with unevenness of the image and distinct abrasion staining.

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A dye mixture for heat-sensitive transfer recording which comprises a dye [A] of the general formula:

wherein R25, R26 and R27 each represents C1 - C8 straight-chain or branched-chain alkyl and a dye [B] of the general formula:
wherein R28 , R29 and R30 each represents C1 - C8 each repre-sents straight-chain or branched-chain alkyl.

2. The dye mixture for heat-sensitive transfer record-ing according to claim 1 wherein the dye [A] accounts for 5 to 95% by weight and the dye [B] accounts for 95 to 5% by weight.

3. The dye mixture for heat-sensitive transfer record-ing according to claim 1 wherein R25 and R28 each represents C1 - C4 straight-chain or branched-chain alkyl, and R26, R27, R29 and R30 each represents C1 - C4 straight-chain alkyl.

4. The dye mixture for heat-sensitive transfer record-ing according to claim 1 which comprises a dye of the structural formula:
and a dye of the structural formula:

5. A method of sublimation heat-sensitive transfer recording, which method comprises heating a transfer sheet having an ink layer containing a sublimable dye coated on a base film to sublime the dye thereby transfer recording onto a recording body, wherein the said dye is the dye mixture as defined in claim 1.

6. A sublimation heat-sensitive transfer recording sheet, which comprises an ink layer containing a heat-sensitive sublimable dye coated on a base film, wherein the said dye is the dye mixture as defined in claim 1.

7. The recording sheet according to claim 6, wherein the ink layer further contains magenta and yellow color dyes.

8. A process for producing a sublimation heat-sensitive transfer recording sheet, which process comprises:
a) dissolving a heat-sensitive sublimable dye in a medium or dispersing the dye in a fine particle form in a medium together with a binder to prepare an ink, and b) coating the in on a base film and drying the coating, wherein the said sublimable dye is the dye mixture as defined in claim 1.