JPS63203393A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To record form a recorded image having high density and excellent fastness, by providing a base sheet and a dye-supporting layer provided on one side of the base sheet, and specifying a dye incorporated in the dye-carrying layer. CONSTITUTION:When a styrene dye having a basic structure of formula I is used for a thermal transfer sheet, an unexpectedly high thermal transfer rate is achieved, and images having excellent fastness, particularly, excellent preservability and light fastness can be obtained upon transferring. In the formula, R1 is hydrogen, a halogen, substd. or unsubstd. alkyl, aryl, cycloalkyl, aralkyl, alkoxyl, acylamino, aminocarbonyl or the like, n is 1 or 2, and each of R2 and R3 is an alkyl or substd. alkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermal transfer sheet, and more specifically, to provide a thermal transfer sheet that can easily provide a recorded image with excellent fastness to a transfer material. Let be 11 targets.

(Prior Art) Various thermal transfer methods are known in the past, among which a sublimation dye is used as a recording agent, this is supported on a base sheet such as paper to form a thermal transfer sheet, and the dye is dyed with a sublimation dye. The thermal transfer sheet is layered on a transferable material such as polynisdel silk cloth, and thermal energy is applied in a pattern from the back side of the thermal transfer sheet.
A sublimation transfer method is used in which a sublimable dye is transferred to a transfer material.

(Problems to be Solved by the Invention) In the sublimation printing method in which the material to be transferred is, for example, polyester woven fabric, etc., thermal energy is applied for a relatively long time. As the material itself is also heated by the applied thermal energy, relatively good dye transfer is achieved.

However, with advances in recording methods, it is now possible to print delicate characters and other images onto these materials, such as polyester sheets or paper with a dye-receiving layer, at high speed using a thermal head or the like. When forming graphics or photographic images, it is necessary to apply thermal energy in an extremely short period of time, on the order of seconds or less.・Since it is not heated at a certain temperature, it is not possible to form an image with a high density.

Therefore, in order to cope with such high-speed recording, sublimable dyes with excellent sublimation properties were developed, but dyes with excellent sublimation properties generally have small molecular weights, so they are difficult to coat after transfer. The dye may migrate over time in the transfer material or bleed onto one surface, causing the well-formed image to become distorted.
Problems arise in that the image becomes unclear or contaminates surrounding objects.

In order to avoid such problems, if a sublimable dye with a relatively large molecular weight is used, the sublimation speed will be inferior in the high-speed recording method as described above, so it will not be possible to form an image with a satisfactory density as described above. Met.

Therefore, in thermal transfer methods using sublimable dyes,
There is a strong demand for the development of a thermal transfer sheet that can produce a clear image with high density in 1 minute by applying thermal energy for an extremely short time as described above, and the formed image exhibits excellent fastness. The current situation is that

As a result of intensive research in response to the strong demands of the industry as described above, the inventor of the present invention discovered that in the conventional sublimation printing method for polyester woven fabrics, etc., the surface of the woven fabric is not smooth, so the thermal transfer sheet and the transfer material cannot be used. It does not adhere to certain silk fabrics for a minute, so the dye used must be sublimable or vaporizable (i.e., capable of moving through the space that exists between the thermal transfer sheet and the woven fabric). However, when the transfer material is a polyester sheet with a smooth surface, a surface-treated paper, etc., the thermal transfer sheet and the transfer material come into close contact with each other during thermal transfer, resulting in problems such as dye dye transferability and vaporization. However, the ability of the dye to migrate through the interface between the two when they are in close contact with each other by heat is also extremely important. Knowing that it is greatly influenced by its location,
By selecting a dye with an appropriate molecular structure,
It has been discovered that even dyes with high molecular weights, which are considered unusable according to conventional wisdom, exhibit good heat transferability. By using a thermal transfer sheet that supports such dyes, the dyes used can be easily transferred to the transfer material even when thermal energy is applied for an extremely short time, resulting in high density and excellent fastness. The present invention was completed based on the finding that a recorded image having a sexiness of 41 can be formed.

(One Step for Solving the Problems) That is, the present invention comprises a base sheet and a dye-carrying layer formed on one side of the base sheet, and the dye contained in the dye-carrying layer is This is a thermal transfer sheet characterized by using a dye represented by general formula (I).

(However, R1 in the above formula is hydrogen source f, halogen source 7-,
Alkyl group, aryl group, cycloalkyl group, arylalkyl group, alkoxy group, which may have substitution JJ4,
It represents a substituent such as an acylamino group or aminocarbonyl^, n represents 1 or 2, and R2 and R, 1 represent an alkyl group or a substituted alkyl group. ) (Preferred Embodiment) Next, the present invention will be described in more detail by citing preferred embodiments. It was discovered that when used as a commercial dye, it exhibits a higher heat transfer rate than F, and furthermore, after transfer, an image with excellent fastness, particularly excellent storage stability and light resistance, can be obtained. In particular, when the molecular weight of the dye was 270 or higher, more preferably 330 or higher, the above effects became more pronounced.

The styrene dye represented by the general formula - is N.

It is obtained by a conventionally known production method in which N-dialkylaniline or a derivative thereof is reacted with tetracyanoethylene.

In the dyes of the present invention obtained as described above, particularly preferred dyes are those represented by 1 in the general formula, where 1 is a hydrogen atom r-, a halogen atom r-, a lower alkyl group such as methyl, ethyl, propyl, butyl, or It is an alkoxy group such as methoxy, ethoxy, propoxy, butoxy group, and has one opening. and R3
is a hydroxyl group, an amino group, an alkylamino group, an acylamino group, a sulfonylamino group, an aminocarbonyl group, an aminosulfonyl group, an alkoxycarbonyl group, an alkoxysulfonyl group, a cyano group, an alkoxy group, a phenyl group, a cycloalkyl group, a halogen atom, or a nitro group. C such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, hexadecyl, etc., which may have a polar substituent such as a group.
It is an alkyl group of I to C20, and is a group selected so that (1) the molecular weight of the dye is 270 or more, more preferably molecule h1 is 330 or more.

According to detailed research by the present inventor, in the dye of the above general formula, by selecting a group other than hydrogen as R1 to R3, such as a substituted or unsubstituted alkyl group, the molecule F2 of the dye increases, Minute? - The amount exceeds 270 or 330, but contrary to the conventional general idea, the melting point of these dyes tends to be low -F, and dyes such as siliceous When used as a dye for thermal transfer sheets, the heat transfer rate of the dye from the thermal transfer sheet to the transfer material increases even by heating for a very short time with a thermal head, etc., and it also has excellent fastness, especially when stored. It has been found that images with excellent durability and light resistance can be obtained using Li.

On the other hand, even if there are styrenic dyes that fall into the above general formula, dyes with a Pi71 of less than 270 may have satisfactory color density, but the storage stability and light fastness of the formed images will be poor. Met.

In addition, the preferred dyes mentioned above include methyl ethyl getone, toluene, ethanol,
The solubility in general-purpose organic solvents such as isopropyl alcohol, cyclohexanone, ethyl acetate, etc. or mixed solvents thereof is significantly improved, and the dye is present in a non-crystalline state or in a low crystalline state in the dye-supporting layer formed on the thermal transfer sheet. It can be used with significantly less deposition than in the highly crystalline state, as is the case with conventional dyes. The dye could easily be thermally transferred to the transfer material with the amount of heat.

The Jt and body side of dyes suitable for the present invention are listed in Table F. Table 1 below shows the substituent R in general formula (1)
9 to R3 and n are not represented.

γJ 1 Knee No R, n--ball, R,- 1 (: 11. 1 c2++5 to 21140112
Cl I L21+5 c2+
+4oph3 el+, 2 C,++5
(:21141]C11340CII, 12 C, 1
15G2114Nllso2C11351so-(,,
, If, 1 (+2115 (:211
z6 n-(:411., IC611
17Cl1ll+77 0C2I+52 G2+1
．． (:N (:2114CN8 N11COC
1132Cl13Lll+9 HI CF
II117 Cll111710C
21152G2115C211401111O(:21
1. i l c2++5C211512[1
r I C2115(:21140111
3CONlIC1131CII+ C211
401114CI+3 1 (:21140C
OCIli hl140GOCI+15C
lb I C211S C211
4-l116 CII+ 1 (:
jllICzllJ((:II+>217 8
I G2115 G21LCOC
113 Comparative Example 1 HI C113C1132HI C
113C2111S 3 HI C2! Is C211s
The thermal transfer sheet of the present invention is characterized by using the above-mentioned specific dye as shown below, and other than that, the structure may be the same as that of a conventionally known thermal transfer sheet.

The base sheet used in the construction of the thermal transfer sheet of the present invention containing the above-mentioned dye may be any conventionally known material having a certain degree of heat resistance and strength, for example, 0.5 to 50 μm, Preferably, paper with a thickness of about 3 to 10 μm, various types of paper, polyester film, polystyrene film, polypropylene film, polysulfone film, polycarbonate film, polyvinyl alcohol film, cellophane, etc. are used, and particularly preferred is polyester film. be.

The dye-carrying layer provided on the surface of the base sheet as described above is a layer in which the dye of the general formula (I) is supported by an arbitrary binder resin.

As the binder resin for supporting the dye,
Any conventionally known materials can be used, and preferred examples include cellulose resins such as ethyl cellulose, droxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose acetate butyrate, polyvinyl alcohol, Examples include vinyl resins such as polyvinyl acetate, polyvinyl butyral, polyvinylpyrrolidone, and polyacrylamide. Among these, polyester is particularly preferred from the standpoint of heat resistance, dye migration, and the like.

The dye-carrying layer of the thermal transfer sheet of the present invention is basically formed from the above-mentioned materials, but may also contain other known outer electrode additives as required.

Such a dye-supporting layer is preferably prepared by adding the dye, binder resin, and other optional components in a suitable solvent, dissolving or dispersing each component, and preparing a coating solution or ink for forming the dye-supporting layer. It is formed by coating 411 on the above base material sheet and drying it.

The support layer formed in this way has a thickness of 0.2 to 5.0 μm.
m, preferably of the order of 0.4 to 2.0 μm, and the dye in the carrier layer is present in an amount of 5 to 70% by weight, preferably 10 to 60% by weight of the weight of the carrier layer. It is preferable to do so.

The thermal transfer sheet of the present invention as described above is fully useful for thermal transfer as it is, but it is also possible to provide an anti-adhesive layer, that is, a release layer, on the surface of the dye-carrying layer. Accordingly, it is possible to prevent adhesion between the thermal transfer sheet and the γJ material to be transferred during thermal transfer, use a higher thermal transfer temperature, and form an image with even better density.

As this type layer, even if an inorganic powder with anti-adhesive properties is attached to the material, it shows a considerable effect, and furthermore, for example,
0.01 to 5 μm from resins with excellent mold release properties such as silicone polymers, acrylic polymers, and fluorinated polymers.
, preferably by providing a release layer with a thickness of 0.05 to 2 μm.

Incidentally, even if the above-mentioned inorganic powder or mold-releasing polymer is included in the dye-carrying layer, a one-minute effect can be achieved.

Furthermore, a heat-resistant layer may be provided on the back surface of such a thermal transfer sheet in order to prevent adverse effects caused by the heat of the thermal head.

The transfer material used to form an image using such a thermal transfer sheet may be any material as long as its recording surface has dye receptivity to the above-mentioned dyes. If the material is paper, metal, glass, synthetic resin, etc. that does not have any properties, a dye-receiving layer may be formed on at least one surface thereof.

Examples of transfer materials that do not require the formation of a dye-receiving layer include polyolefin resins such as polyethylene and polypropylene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, and polyacrylic ester. vinyl polymers such as polyethylene terephthalate, polyester resins such as polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene with other vinyl monomers, ionomers,
Examples include fibers, woven fabrics, films, sheets, and molded products made of cellulose resins such as cellulose diacetate and cellulose triacetate, polycarbonate, polysulfone, and polyimide.

Particularly preferred are sheets or films made of polyester, or processed paper provided with a polyester layer. In addition, even for paper, metal, glass, and other non-stainable transfer materials, a solution or dispersion of the above-mentioned non-staining resin is applied and dried on the recording surface, or the resin is By laminating the film, it can be used as a transfer material.

Historically, even if the transfer material listed in Y-7 has non-adhesion properties, a dye-receiving layer may be formed on its surface from a resin with better non-adhesion properties, as in the case of the above-mentioned paper. good.

The dye-receiving layer formed in this way may be formed from a single material or from a plurality of materials, and may also contain various additives as long as they do not interfere with the intended purpose. Of course.

Such a dye-receiving layer may be of any thickness, but typically has a thickness of 5 to 50 μm. Although such a dye-receiving layer is preferably a continuous coating, it may be formed as a discontinuous coating using a resin emulsion or a resin liquid.

Such a transfer material is basically as described above and can be used as is for one minute, but it is possible to incorporate an inorganic powder for preventing adhesion into the transfer material or its dye-receiving layer. In this way, even if the temperature at the time of thermal transfer is increased, adhesion between the thermal transfer sheet and the material to be transferred can be prevented, and even cooler thermal transfer can be performed. Particularly preferred is finely powdered silica.

Further, in place of or in combination with the above-mentioned inorganic powder such as silica, the above-mentioned resin having good mold releasability may be added. Particularly preferred release polymers include cured products of silicone compounds, such as cured products of epoxy-modified silicone oil and amino-modified silicone oil.

Such a release agent preferably accounts for about 0.5 to 30% by weight of the dye-receiving layer.

In addition, the transfer material to be used may have an inorganic powder as described above attached to the surface of the dye-receiving layer to enhance the anti-adhesive effect, or a mold release agent with excellent mold release properties as described above. A layer consisting of may be provided.

Such a release layer exhibits a sufficient effect at a thickness of about 0.01 to 5 μm, and can further improve dye receptivity while preventing adhesion to the dye receptive layer of the thermal transfer sheet.

As the means for applying thermal energy used when performing thermal transfer using the thermal transfer sheet of the present invention as described above and the recording material as described above, any conventionally known applying means can be used.
For example, by controlling the recording time using a recording device such as a thermal printer (for example, Toshiba ■Thermal Printer TN-5400),
By applying thermal energy on the order of 0 mJ/mgo, the intended purpose can be achieved in 1 minute.

(Function/Effect) According to the present invention as described above, as already partially explained, the dye of general formula (I) in 11η used in the composition of the thermal transfer sheet of the present invention is different from that of the conventional thermal transfer sheet. Noboru was used? Although it has a significantly higher molecular weight than ℃-based dyes (approximately 150 to 250 minutes), it has a specific structure and has substituents at 1, L specific positions, so It exhibits excellent heat transferability, dyeability and coloring properties on the transfer material, and does not migrate into the transfer material or bleed out onto the surface of the transfer material after transfer.

Therefore, the image formed using the thermal transfer sheet of the present invention has excellent fastness, especially migration resistance and stain resistance (f), so that the sharpness of the formed image will not be lost even after long-term storage. The various problems of the prior art are solved without causing any damage or contamination of other articles.

In particular, in the case of a dye of the general formula (I) in which at least one of R1 to R3 has a polar group, the fastness as described above becomes even more remarkable.

Such excellent effects, which cannot be imagined with conventional techniques, are especially noticeable when the dye-receiving portion of the transferred material is made of a material such as polyester. Due to the correlation with the ester bond, it is thought that it is fixed in the polyester by some action.

Next, the present invention will be further described in detail with reference to Reference Examples, Examples, and Comparative Examples. In the text, parts or percentages are based on weight unless otherwise specified.

Reference Example 1 A styrene dye represented by the following structural formula was obtained by reacting a compound represented by the following formula with tetracyanoethylene according to a conventional method.

I got it.

Reference Examples 2 to 17 and Comparative Reference Examples 1 to 3 N of Reference Example 1
The styrenic dyes listed in Table 1 were obtained in the same manner as in Reference Example 1 except that the compounds listed in Table 1 were used in place of , N-dialkylaniline. The dye of Reference Example 1 is also shown in Table 1.

Examples and Comparative Examples An ink composition for forming a dye-carrying layer having the composition described in F was prepared and applied to a 6 μm thick polyethylene terephthalate film whose back surface had been heat-resistant treated so that the dry coating amount was 1.0 g/♂. and dried to obtain thermal transfer sheets of the present invention and comparative examples.

Dyes listed in Table 1 of 11η 3 parts Polybutyral resin 4.5 parts Methyl ethyl ketone 46.25 parts Toluene
46.25 parts Next, synthetic paper (YUBO FPG #150, manufactured by Ichigo Yuka Co., Ltd.) was used as a base sheet, and a coating liquid having the following composition was applied to one side of the paper at a dry rate of 10.0 g/m'.
The coating material was coated at a ratio of 100° C. and dried at 100° C. for 30 minutes to form a coating material of 1 il.

Polyester resin (Vylon200, manufactured by Toyobo) 11
．． 5 parts vinyl chloride/vinyl acetate copolymer (VY song.

Mouth CC 4)
5.0 part amino-modified silicone (KF-:193, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.
2-part epoxy-modified silicone (X-22-34:l, manufactured by Shin-Etsu Chemical) 1.2
Methyl ethyl ketone/toluene/cyclohexanone (
Nail q ratio 4:4:2'> 102.0 parts The thermal transfer sheets of the present invention and comparative examples and the transfer material described above are stacked with their respective dye-carrying layers and dye-receiving surfaces facing each other, Head applied voltage tO from the back side of the thermal transfer sheet
Recording was performed with a thermal head under the conditions of V and printing time of 4.0 m5 ec, and the results shown in Table 2 below were obtained.

(F margin) γ-J 2 Knee 1 2.21 Δ 02802
1.75 0 0 :17
6.53 2.15 0 0
3084 1.72 0 0
4035 2.30 Δ 0
2786 1.20 0 0474
j +, 95 0 0 3438
2.10 0 0 3369
1.53 0 Q 41
810 2.07 0 0
32211 2.23 0 0
29412 1.94 0 0
3441:l 2.23 0
0 30914 1.74 0
0 30815 1.93
0 0 34616 2.00
0 0 335 was marked as ×.

+7 1.95 0 0
:16B Agematsu example! 1.97 x O22
221,92X O2:16'J 2.02 x O2
50 The hues of the dyes in the table above are all red.

The color density mentioned above is a value measured with a densitometer RD-918 manufactured by Macbeth Corporation in the United States.

Storage stability is rated ◎ if the sharpness of the image does not change after the recorded image is left in an atmosphere at 50°C for a long time, and the blank paper does not become colored even if the surface is covered with a blank paper (+9). When the image was lost and the white paper was slightly colored, it was marked as ○, when the sharpness was lost and the white paper was colored, it was marked as Δ, and when the image became unclear and the white paper was markedly colored, it was marked as ×.

Light resistance is based on JIS L 0842.
0841, those with an initial fastness of grade 3 or higher in the second exposure method are marked as ◎, those of about grade 3 are marked as 0, and those with lower initial fastness are marked as 183:i. (Spontaneous) Patent applicant Dai Nippon Printing Co., Ltd. Agent Patent attorney Yoshi rfl Katsu Hiro 1986
June 11-1

Claims (4)

[Claims] (1) Consists of a base sheet and a dye-supporting layer formed on one side of the base sheet, and the dye included in the dye-supporting layer is a dye represented by the following general formula (I). A thermal transfer sheet featuring ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R_1 in the above formula is a hydrogen atom, a halogen atom,
Represents a substituent such as an alkyl group, aryl group, cycloalkyl group, arylalkyl group, alkoxy group, acylamino group, or aminocarbonyl group that may have a substituent, and n
represents 1 or 2, and R_2 and R_3 represent an alkyl group or a substituted alkyl group. ) (2) The thermal transfer sheet according to claim (1), wherein the dye has a molecular weight of 270 or more. (3) The thermal transfer sheet according to claim (1), wherein the dye has a molecular weight of 330 or more. (4) At least one of the substituents R_1 to R_3 is a hydroxyl group, an amino group, an alkylamino group, an acylamino group,
The claimed group is a group having a polar group such as a sulfonylamino group, an aminocarbonyl group, an aminosulfonyl group, an alkoxycarbonyl group, an alkoxysulfonyl group, a cyano group, an alkoxy group, a phenyl group, a cycloalkyl group, a halogen atom, or a nitro group. Thermal transfer sheet according to scope item (1).