JPS63290793A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To record images having a high density and excellent fastness, by incorporating a specified dye into a dye carrier layer. CONSTITUTION:A thermal transfer sheet comprises a base sheet and a dye carrier layer provided on one side of the base sheet, the dye carrier layer comprising a dye of formula I, wherein R1 is a substd. or unsubstd. alkyl, cycloalkyl, alkylaryl or aryl, R2 is hydrogen, a halogen, alkyl, cycloalkyl, alkoxyl, acylamino, aminocarbonyl, alkylaryl or aryl, n is an integer of 1 or 2, and each of R3 and R4 is a substd. or unsubstd. alkyl or hydrogen. The dye of formula I is excellent in thermal transfer properties, properties for dyeing a transfer recording material and color forming properties, and is free of migration in the transfer recording material or bleeding out to the surface of the recording material after transfer.

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. With the goal.

(Prior Art) Various thermal transfer methods have been known in the past, but among them, a sublimation dye is used as a recording agent, this is carried on a base sheet such as paper to form a thermal transfer sheet, and the dye is dyed with a sublimation dye. Layer it on a transferable material, such as polyester silk cloth, and apply thermal energy from the back side of the thermal transfer sheet in a buttery-like manner.
A sublimation transfer method is used in which a sublimable dye is transferred to a transfer material.

(Interlayer point to be solved by the invention) In the above-mentioned sublimation printing method, in which the material to be transferred is, for example, polyester silk cloth, heat energy is applied for a relatively long time, so the material to be transferred itself As a result, relatively good dye migration is achieved as a result of the heat applied to the dye.

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, it is not possible to form an image with sufficient 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 do not dissolve in the transferred material after transfer. Problems arise in that the dye migrates over time or bleeds onto the surface, resulting in the well-formed image becoming distorted or unclear, or contaminating surrounding articles.

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 described above, so it will not be possible to form an image with a satisfactory density as described above. It was something that didn't exist.

Therefore, in thermal transfer methods using sublimable dyes,
At present, there is a strong demand for the development of a thermal transfer sheet that can provide sufficiently dense and clear images by applying thermal energy in an extremely short period of time as described above, and also exhibits excellent fastness of the formed images. It is.

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. Some woven fabrics do not adhere sufficiently, so the dye used must be sublimable or vaporizable (i.e., capable of moving through the space 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 during thermal transfer, so only the sublimation and vaporization properties of the dye are affected. is not an absolute requirement, but the ability of the dye to migrate through the interface between the two in close contact with each other by heat is also extremely important.The thermal migration property of such an interface depends on the chemical structure of the dye used, the substituents, and their positions. found that it is greatly influenced by
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, have good thermal 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 period of time, resulting in high density and excellent fastness. The present invention was completed by discovering that a recorded image having the following characteristics can be formed.

(Means for solving interlayer points) That is, the present invention comprises 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 This is a thermal transfer sheet characterized by using a dye represented by the following general formula (I).

However, R1 in the above formula represents an alkyl group, cycloalkyl group, alkylaryl group, or aryl group that may have a substituent, and R2 represents a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, represents an acylamino group, an aminocarbonyl group, an alkylaryl group or an aryl group, n represents an integer of 1 or 2, R3 and R4
represents an alkyl group or a hydrogen atom which may have a substituent.

Next, to explain the present invention in more detail, the dye represented by the general formula (I), which mainly characterizes the present invention, is produced by a conventionally known coupling method of a p-phinidine diamine compound and a naphthol. That's what you get.

As a result of continuing detailed research on the suitability of such dyes as dyes for thermal transfer sheets such as the present invention, the present inventor found that only the dyes represented by the general formula (I) have a molecular weight It has excellent heat transferability even if the transfer material is relatively large, and also shows excellent dyeing and coloring properties on the transferred material, and also shows excellent transferability of the dye in the transferred material (
It was discovered that the dye exhibits no bleeding (bleeding) and has extremely ideal properties as a dye for thermal transfer sheets.

In the dye of general formula (I) that is particularly preferred in the present invention, the substituent GOOR is located at the 2-position of the naphthalene ring, and Ro is a phenyl group, CI to C6
is an alkyl group or a cycloalkyl group,
The presence of such groups provides blue dyes of deeper hue with high light fastness, migration resistance, etc.

Furthermore, R2 is preferably a hydrogen atom, one chlorine atom, a methyl group or a methoxy group.

Also, regarding R3 and R4, both are C1 to C1
The best result, that is, an alkyl group of It had excellent transferability, dyeability to the transferred material, heat resistance during transfer, color development, and excellent transferability after transfer.

Specific examples of dyes suitable for the present invention are listed below. Table 1 below shows the substituents R1 to R4 and n in general formula (I), in which the GOOR group is present adjacent to the quinone group of the naphthalene ring.

1 = Ndan, ``nee-''mad--1-m-'' 工----also-l
ph CH31(:2)15 C21140
82ph HI CJs CaLO+13
ph-OH, OCH31C2H3C2H, OH4p
h C1I C2)1sCi)1.0)15
ph C832C2H5(:2H,0)16
CH3HI G2)15C,84N)ls0
2cH.

7 C, H5Br 1 (:83
CH38C3)17 CH31(:8H1
7Ca)ItA9 C4119(:211S
I D2H4CN C2H4CN -1
0C3)111)1 1 CH3C
H3II cyccgll, cl+, 2
CaH+y CaH+y12 C1h
C0N) IC4H91C2H6C2H401 (1:l
ph NHCOCIh l (:*t
ls CzHs14 CH2-ph oc2I
IS2 CtHa C2H4OH+5
ph 0 (28s IG) 13
C11140H+6 CJs C) Is
I C2H, [;2H40)117 C3H
? C1131C2115C2) 140H+8 1
so-(:sH, OCI+31 C2H5Cz)
1g19 C411! (:H31Ca11g
(:2H40H20CaHs C1I
HH21C4)19 (:l 2
HH221so-C,)Is C12C
2H5C2H823sec, -C,11,QC,t15
1 Ca1l, C21+, 0H24phC
12) IH 25ph 11 1ph
H26ph-Go, elfs I
Czlls C21140H27ph-c21+5
cH31C2Ha CJs28 ph-CiHt
(J132H)! 29I(:11111
1 30 n (:l!32 8
HI: ph-iso-C,H.

II: ph-sec-G, H9 The thermal transfer sheet of the present invention is characterized by using the above-mentioned specific dye, and the other 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 processed papers, polyester film, polystyrene film, polypropylene film, polysulfone film, polycarbonate film, aramid 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, and polyvinyl alcohol. Examples include vinyl resins such as vinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinylpyrrolidone, and polyacrylamide. Among these, polyvinyl acetal is particularly preferred from the viewpoint 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 various conventionally known 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 and drying on the above base sheet.

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

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. This prevents adhesion between the thermal transfer sheet and the transfer material during thermal transfer, allows use of a higher thermal transfer temperature, and forms images with even better density.

As this mold release layer, even if an inorganic powder with anti-adhesive properties is simply attached, it has a considerable effect. It can be formed by providing a release layer with a thickness of 0.01 to 5 μm, preferably 0.05 to 2 μm.

Incidentally, the above-mentioned inorganic powder or mold-releasing polymer can have a sufficient effect even if it is included in the dye-carrying layer.

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 the thermal transfer sheet as described above 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., which does not have a dye, 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 bo-ribropyrene, halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, and vinyls such as polyvinyl acetate and polyacrylic ester. Polymers, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, ionomers, cellulose resins such as cellulose diacetate, etc. Examples include fibers, woven fabrics, films, sheets, and molded products made of polycarbonate and the like.

Particularly preferred are sheets or films made of polyester, or processed paper provided with a polyester layer. In addition, even if the transfer material is non-dyeable such as paper, metal, glass, etc., a solution or dispersion of a dyeable resin such as those mentioned above is coated on the recording surface and dried, or the resin is By laminating the film, it can be used as a transfer material.

Furthermore, even if the transfer material has the dyeability described above, a dye-receiving layer may be formed on the surface thereof from a resin having better dyeability, as in the case of the paper described above.

The dye-receiving layer formed in this manner may be formed from a single material or from a plurality of materials, and may also contain various additives as long as the intended purpose is not hindered. 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 also be formed as a discontinuous coating using a resin emulsion or resin dispersion.

Such a transfer material is basically as described above and can be used as is, 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 during thermal transfer is increased, adhesion between the thermal transfer sheet and the material to be transferred can be prevented, and even better 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 may be used in an amount of about 0.5 to 3 by weight of the dye-receiving layer.
A ratio of 0% by weight is good.

The transfer material to be used may have an inorganic powder as described above adhered to the surface of the dye-receiving layer to enhance the anti-adhesive effect, or a mold release material with excellent mold release properties as described above may be used. A layer consisting of an agent may also 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, Video Printer VY-100 manufactured by Hitachi), it is possible to
By applying thermal energy of approximately J/mnf, the intended purpose can be fully achieved.

(Operation/Effect) According to the present invention as described above, as already partially explained, the general formula (
Although the dye I) has a significantly higher molecular weight than the sublimable dyes (molecular weight approximately 150 to 250) used in conventional thermal transfer sheets, it has a specific structure, and Because it has a substituent at a specific position, it exhibits excellent heat transferability, dyeing and coloring properties on the transferred material, and after transfer, it does not migrate into the transferred material or bleed out onto the surface. It is something that does not happen.

Therefore, since images formed using the thermal transfer sheet of the present invention have excellent fastness, especially migration resistance and stain resistance, the sharpness of the formed images will not be impaired even after long-term storage. Also, there is no contamination of other articles, and various problems of the prior art have been solved.

In particular, as the dye of the general formula (I), the C0OR+ group is 2-
In the case of dyes in which R8 is phenyl and at least one of R3 and R4 is a group having a polar group, the fastness as described above becomes even more remarkable. Such excellent effects that cannot be imagined using conventional techniques are especially noticeable when the dye-receiving portion of the transferred material is made of a material such as polyester, because the dye has ester bonds and other polar groups. It is also thought that it is fixed in the polyester by some action due to the correlation with the ester bond, which is a polar group in the polyester.

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

Example 1 2.64 parts of a compound represented by the following structural formula was added to 200 parts of 95% ethanol.
An aqueous solution prepared by dissolving 5 parts of anhydrous sodium carbonate in 50 parts of water was added to the resulting solution to prepare a mixed solution.

Next, 3.41 parts of a compound represented by the following structural formula was dissolved in 5 parts of water, and the resulting solution was added to the above mixed solution and after thorough stirring, 12.5 parts of a sodium hypochlorite solution was added. 1 part is gradually added, stirred in this state for 15 minutes, filtered, and washed with pure water. When the filtrate becomes neutral, it is dried, the product is dissolved in ethyl acetate, column rusting is performed using ethyl acetate/hebutane, and dyes with the following structural formula [No. ] was obtained.

Example 2 The dyes listed in Table 1 above were obtained in the same manner as in Example 1, except for using different raw materials.

Example 3 An ink composition for forming a dye-carrying layer having the following composition was prepared, and applied and dried to a 9 μm thick polyethylene terephthalate film whose back surface had been heat-resistant treated so that the dry coating amount was 1.0 g/m'. A thermal transfer sheet of the present invention was obtained.

Dyes of Table 1 3 parts Polybutyral resin 4.5 parts Methyl ethyl ketone 46.25 parts Toluene
46.25 parts Next, synthetic paper (Yupo FPG #150, manufactured by Tamago 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/rn''.
It was coated at a ratio of 100 tons and dried for 3 parts to obtain a transfer material.

Polyester resin (Vylon200, manufactured by Toyobo) 11
．． 5 parts vinyl chloride-vinyl acetate copolymer (VYH) 1% UCC
5.0 parts amino-modified silicone (KF-393, manufactured by Shin-Etsu Chemical Co., Ltd.)
1.2@Epoxy modified silicone (X-22-343, manufactured by Shin-Etsu Chemical)
1.2 parts methyl ethyl ketone/
Toluene/cyclohexanone (weight ratio 4:4:2)
102.0 parts The above-described thermal transfer sheet of the present invention and the above-mentioned transfer material were overlapped with their respective dye-carrying layers and dye-receiving surfaces facing each other, and a head applied voltage of 10 V from the surface of the thermal transfer sheet was applied for a printing time. Recording was performed with a thermal head under conditions of 4.0 m5 ec, and the results shown in Table 2 below were obtained.

Comparative Example The dyes shown in Table 3 below were used as the dyes in Example 3, and the other conditions were the same as in Example 4 to obtain the results shown in Table 3 below.

However, the composition of the ink composition for forming the dye-carrying layer was as follows.

Dyes in Table 3 below 3 parts Polybutyral resin 4.5 parts Methyl ethyl ketone 46.25 parts Toluene
46- 25 part 1;- 11,35O indigo 454 2 142 ◎ Indigo 4
403 1.16 ◎ Supervisor 484
4 1.23 ◎ Indigo 474.5
5 1.29 ◎ Indigo 46
86 1.34 ◎ Indigo 4
55.17 1.51 ◎
Indigo 426.98 0.82
◎ Indigo 5729 1, +7
◎ Indigo 48210 1.72
0 1 390+1 0.69
◎ Indigo 62712 1.24
◎ Indigo 47713 1
．． 17 ◎ Indigo 48114
0.91 ◎ Indigo 54315
1.26 ◎ Indigo 4701B
1.62 ◎ Indigo 4
0617 1.56 ◎ Indigo 42018 1.59 ◎
Indigo 42019 1.47 ◎
Indigo 43420 1.74 0
Indigo 382.521 +, 54
◎ Indigo 417.922 1
．． 25 ◎ Indigo 473.923
1.29 ◎ Indigo 4642
4 1.45 ◎ Indigo 437
．． 925 +, 41 ◎
Indigo 44426 1.27 ◎
Supervisor 46827 1.28 ◎
Indigo 46628 1.41
◎ Indigo 44029 1.3
3 ◎ Indigo 458.530
1.36 ◎ Indigo 453 The dyes in the above table are indicated by the numbers in Table 1 above.

γ 3 - 1' A1 1 0.99 x Indigo 2 1
．． 16Δ Indigo 3 2.07 X Indigo 4 1
．． 12Δ Indigo 5 1.02 x Purple Shang The dyes in the above table are as follows.

1: C, 1, Disperse Blue 14 2: (:, 1. Disperse Blue 1343: (nee 1. Solvent Blue 63 4: C, 1, Disperse Blue 26 5: C, 1, Disperse Violet 4) The coloring densities in Tables 2 and 3 above are values measured with a densitometer RD-918 manufactured by Macbeth, USA.

Fastness 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 white paper does not become colored even when the surface is rubbed with white paper. If the image is lost and the white paper is slightly colored, it is O. If the sharpness is lost and the white paper is colored, it is Δ. If the image is unclear and the white paper is significantly colored, it is called X.
It was displayed in

Procedure NedT official document (voluntary) July 1, 1986

Claims (1)

[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.▼ (I) (However, R_1 in the above formula represents an alkyl group, cycloalkyl group, alkylaryl group, or aryl group that may have a substituent, and R_2 is a hydrogen atom. , represents a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an acylamino group, an aminocarbonyl group, an alkylaryl group, or an aryl group, n represents an integer of 1 or 2, R_3
and R_4 represents an alkyl group or a hydrogen atom that may have a substituent. )