JPH03124492A - Sublimating dye thermal transfer picture image acceptable sheet - Google Patents

Abstract

PURPOSE:To enhance the sensitivity and density of a picture image, and to improve shelf stability by forming an accepting layer mainly comprising a polyester resin to a support and composing a resin of the copolycondensation product of a specified diol component and a dicarboxylic acid component. CONSTITUTION:A sheet has a sublimating dye thermal transfer picture image accepting layer mainly comprising a polyester resin on at least one surface of a sheet-shaped support, and the copolycondensation product of a diol component including ethylene glycol, neopentyl glycol and a bisphenol A-alkylene oxide adduct shown in formula and a dicarboxylic acid component containing terephthalic acid and isophthalic acid is used as a resin, and the resin has a glass transition point of 65 deg.C or higher. A sheet-shaped support can be selected from wood free paper, coated paper, various plastic films, these composite laminated sheets, etc. Accordingly, the sheet having the high sensitivity of a picture image and high color-development density and excellent shelf stability is acquired.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sublimable dye thermal transfer image-receiving sheet. More specifically, the present invention relates to a sheet used in a thermal transfer printer and capable of receiving full-color painting using sublimable disperse dyes.

The image-receiving sheet of the present invention has a high density and clear image, and has excellent heat resistance and other storage properties.

[Prior Art/Problems to be Solved by the Invention] In recent years, the development of high-quality color hard copies using thermal transfer methods, especially dye transfer printers, has progressed rapidly. In such a dye transfer printer, when heating the sublimable dye layer of the three colors (yellow, magenta, and cyan) of Inksee I, the heating energy of the thermal head is continuously controlled, and the heating energy of each color is controlled continuously. By changing the amount of dye transferred, it is possible to transfer full-color images with different density gradations.

In order to obtain high-quality images on the image-receiving sheet I used for such applications, it is necessary to develop a dye-dyed layer that has a fast dye transfer speed, a large amount of dyeing, and has good storage stability. is strongly desired.

That is, an image receiving sheet for sublimation dye thermal transfer has an image receiving layer mainly composed of a thermoplastic resin that is easily dyed with the dye transferred from the ink sheet, but it is possible to make this layer even more sensitive. In order to achieve this, it is desired that the dye transfer speed and dyeing amount be increased. In addition, the image-receiving layer has been required to have good dye retention under various storage conditions, but a satisfactory one has not been obtained.

Conventionally, in contrast to such sublimable dyes, dyeing resins that have a high transfer speed and dyeing amount and have excellent storage stability are:
Various polyester resins have been proposed.

For example, it has been proposed to use a polyester resin with a low glass transition point in order to obtain a dyeable resin with a high transfer rate and/or a high dyeing amount. That is, in order to lower the glass transition point of polyethylene terephthalate 1~, which is a polycondensation product obtained from a glycol component consisting of ethylene glycol and a dicarboxylic acid component consisting of terephthalic acid, a different type of diol, A method of copolymerizing dicarboxylic acids has been proposed. but,
If a polyester resin with a lower glass transition point is used, the transfer speed and/or dyeing amount of the resulting image-receiving layer will increase, but the strength of the image-receiving layer at high temperatures will decrease, and therefore, during the printing process, the strength of the image-receiving layer will decrease. This has caused problems such as fusion that reduce running performance.

In order to obtain a dyeable resin with excellent storage stability, contrary to the above requirements, it is necessary to raise the glass transition point, and if this is done, the transfer speed and/or the dyed layer may be reduced. There was a problem with becoming.

The present invention solves the above-mentioned drawbacks of the prior art, improves image sensitivity,
Another object of the present invention is to provide a sublimable dye thermal transfer image-receiving sheet that has high density and excellent storage stability against heat and light.

[Means to solve the problem]

The sublimable dye thermal transfer image-receiving sheet of the present invention includes a sheet-like support, and formed on at least one surface of the support,
and a sublimable dye thermal transfer image receiving layer containing a polyester resin as a main component, wherein the polyester resin contains (A) ethylene glycol, neopentyl glycol, and bisphenol A represented by the following formula (I).
-Alkylene oxide adduct: [However, in the above formula, R1 and R2 each independently represent a member selected from a hydrogen atom and a methyl group, ... and n each independently represent the following A copolycondensation product of: (B) a dicarboxylic acid component containing terephthalic acid and isophthalic acid; It is characterized by having a glass transition point of 65°C or higher.

The polyester resin used in the present invention contains a diol component containing at least three specific components, and at least two specific components.
It is a copolymerized polyester resin obtained by a polycondensation reaction with a dicarboxylic acid component. Such a diol component contains ethylene glycol, neopentyl glycol, and the bisphenol A-alkylene oxide adduct represented by the above-mentioned successive (I), and the dicarboxylic acid component contains at least terephthalic acid and isophthalic acid. It includes. Further, the copolyester resin used in the present invention has a glass transition point of 65°C or higher -F.

The conventional method of increasing the sensitivity and dyeing amount of the image-receiving layer by lowering the glass transition point of the polyester resin has resulted in runnability problems such as fusion of the resulting image-receiving sheet, and decreased storage stability. This resulted in unfavorable results. Through research by the present inventors, we have found that the sensitivity and dyeing amount of the image-receiving layer do not depend on the glass transition point itself of the dyeing resin contained therein, but rather on the dye diffusivity and dye solubility of the dyeing resin. It has become clear that it depends on Based on these research results, the present inventors believed that a resin with high dye solubility and a high glass transition point would be suitable as the main component of the image-receiving layer, and developed the copolyester resin according to the present invention. That's what I did. That is, in copolycondensation of polyester resin, ethylene glycol and
By using neopentyl glycol and the bisphenol A-alkylene oxide adduct represented by the above-mentioned maximum (I) as the main components of the diglycol component, and using terephthalic acid and isophthalic acid as the main components of the dicarboxylic acid, This made it possible to prepare a polyester that has a glass transition point of 65° C. or higher and also has satisfactory dyeability with sublimable disperse dyes.

The copolymerized polyester resin used in the present invention has greater sensitivity and dyeing amount in sublimation dye thermal transfer than conventional polyester resins, and has no running problems such as fusion.
This made it possible to create an image-receiving sheet with good storage stability.

In particular, to the bisphenol represented by maximum (I) above-
Ethylene oxide adducts are effective in increasing dye affinity without lowering the glass transition temperature of the resulting polyester resin, and neopentyl glycol is also effective in increasing the dye solubility of the resulting polyester resin. It is valid.

Among the components used in the polycondensation of the polyester resin, the diol component is preferably a three-component mixture of ethylene glycol, neopentyl glycol, and - up to (I) bisphenol (A)-alkylene glycol adduct. contains 80 mol% or more, and if necessary, 30 mol% or less of other glycol compounds, such as difunctional aliphatic glycols such as propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-bentanediol, 1,6-hexanediol, diethylene glycol, and dipropylene glycol, and alicyclic glycols such as 1,4
cyclohexane dimetatool, etc., and at least one member selected from three or more polyfunctional glycols, such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and the like.

In the diol component, ethylene glycol is
Preferably it is present in a content of 0 mol%, neopentyl glycol is preferably present in a content of 5 to 30 mol%, and - up to (I) bisphenol A
- The content of the alkylene glycol adduct is preferably 40 mol% or more, more preferably 50 to 70 mol%.

The dicarboxylic acid component used in the preparation of the polyester resin of the present invention preferably contains 70 mol% or more of a binary mixture of terephthalic acid and isophthalic acid, and if necessary,
50 mol% of at least one other polyfunctional carboxylic acid
May contain the following:

Such other carboxylic acids include, for example, aromatic dicarboxylic acids, such as orthophthalic acid, and 2,6-naphthalene dicarboxylic acid; aliphatic dicarboxylic acids, such as succinic acid, adipic acid, azelaic acid, sebacic acid. , dodecanedioic acid, and dimer acid; alicyclic dicarboxylic acids, such as 1,4-cyclohexanedicarboxylic acid; and aromatic polycarboxylic acids, such as tri- or higher-functional polycarboxylic acids, such as trimellitic acid, pyromellitic acid, etc. It can be derived from carboxylic acids as well as aliphatic polycarboxylic acids such as butanetetracarboxylic acid and the like.

In the dicarboxylic acid component used for preparing the polyester resin of the present invention, the content of terephthalic acid is preferably 30 to 70 mol%, and the content of isophthalic acid is 1
It is preferably 0 to 50 mol%.

The polyester resin of the present invention may be used alone or in combination with other polyester resins, acrylic resins (!1
It can be used in the image-receiving layer as a blend with a vinyl acetate resin or other thermoplastic resin or solvent-soluble synthetic resin. However, the image-receiving layer of the present invention has
It is preferable that the polyester resin is contained in an amount of 70% by weight or more as its main component.

The image-receiving layer of the present invention may contain a silicone compound effective as a mold release agent for the purpose of preventing heat fusion with the ink ribbon during printing. At this time, the blending amount of the silicone compound is preferably 0.1 to 10%. If this amount exceeds 10%, the adhesion between the image-receiving layer and the support may be impaired. Moreover, if it is less than 0.01%, the effect of preventing heat fusion will not be sufficiently exhibited.

A crosslinking agent may be added to the image-receiving layer of the present invention. Such a crosslinking agent crosslinks polyester or the like to make the polymer constituting the image-receiving layer three-dimensional, thereby improving the heat resistance of the dyeable image-receiving layer. As the crosslinking agent, for example, a polyfunctional isocyanate compound is used. usually,
If the amount of the crosslinking agent added is too large, the resulting image-receiving layer will be too hardened, resulting in decreased dye receptivity and decreased sensitivity. Therefore, the amount of the crosslinking agent added is preferably 20% by weight or less, more preferably 10% by weight or less, based on the weight of the image-receiving layer. However, the amount of crosslinking agent added is 1
If the amount is less than % by weight, sufficient effects are generally not obtained.

The image-receiving layer of the present invention contains a substituted phenol or a low-molecular organic compound such as a terpene for antioxidant, ultraviolet absorption, and
They may be blended for purposes such as sensitization.

White pigments that are generally used to improve the whiteness and opacity of paints, fluorescent dyes that have conventionally been used to adjust the color tone of image-receiving layers, and dyes such as blue and violet can also be used in the present invention as needed. It may be added to the image-receiving layer.

Additives such as the above-mentioned white pigment, ultraviolet absorber, and crosslinking agent are generally mixed with the polyester resin, which is the main component of the image-receiving layer, and then coated on a predetermined surface of the support. However, the UV absorber may be applied as a separate coating layer above or below the image-receiving layer.

Generally, the thickness of the image-receiving layer is between 1 and 20 g/m2, preferably between 4 and 10 g/m2. If this thickness is too thin, the density and sensitivity of the image will decrease, and the coating accuracy will also decrease, resulting in poor image uniformity. On the other hand, if the thickness is too large, the effect is saturated and not only is it uneconomical, but also the mechanical strength of the image-receiving layer is reduced.

When an image-receiving sheet is run in a printer, static electricity is generated, which may cause running troubles. To prevent this, it is possible to apply an antistatic agent to at least one surface of the sheet. preferable. The antistatic agent may be added into the image-receiving layer or may be applied as a back coat.

Cationic hydrophilic polymers are generally used as antistatic agents.

Depending on the purpose, the sheet-like support used in the present invention may include various plastic films such as high-quality paper, coated paper, synthetic paper consisting of a monoaxially or biaxially stretched film formed mainly of polyolefin and inorganic pigments, and other plastic films. You can choose from laminated sheets made of composite materials. Examples of composite sheets include laminated sheets in which polyethylene is laminated on both sides of high-quality paper or coated paper. The thickness of the support used in the present invention is 20 to 250μ
m is preferable, and its basis weight is 20 to 250
g/m2 is preferred.

〔Example〕

The invention will be further illustrated by the following examples.

A polyester copolymer was produced from a dicarboxylic acid component and a diol component having the following composition.

Dicarboxylic acid component composition Terephthalic acid 60 mol% (99.7 g)
Isophthalic acid 40 mol% (66.5g)
Diol component: Roasted ethylene glycol 20 mol% (21.2 g)
Neopentyl glycol 20 mol% (23.2 g)
Diol (I) (trademark: Uniol DA400, manufactured by Nippon Oil & Fats Co., Ltd., n + m = 4.0 in formula (I)) 60 mol% (
I07.0g> The above dicarboxylic acid component and diol component are heated in a nitrogen atmosphere in the presence of a trace amount of a catalyst consisting of calcium acetate and antimony trioxide, and 15
After raising the temperature to 0° C., this temperature was maintained for 1 hour to allow both components to react. While maintaining this reaction system in a vacuum of 0.1 mm and 11 g or less, polycondensation reaction was further carried out at 250°C for 2 hours, and at the same time, unreacted ethylene glycol was removed. Polyester resin-1 was obtained. The molecule i (according to GPC) of this resin was 20.000, and the glass transition point was 75°C.

Synthesis Example: Synthesis of Polyester Resin-2 A dicarboxylic acid component and a polyol component having the following composition were polycondensed.

Tsusajikin/Material component Terephthalic acid 60 mol% (99.7g)
Isophthalic acid 40 mol% (66.5g)
2 to 27 flame-linked ethylene glycol 30 mol% (I8.6g>
Neopentyl glycol 20 mol% <13.1g)
Diol (I) (same as Synthesis Example 1) 50 mol % (200.0 g) The composition of components other than the diol component and the reaction conditions were the same as in Synthesis Example 1 to obtain Polyester Resin-2. This resin had a molecular weight of 20,000 and a glass transition point of 69°C.

A comparative polyester resin was produced by polycondensing a dicarboxylic acid component and a diol component having the following composition.

@M-”/Brewing” U [Terephthalic acid 60 mol% (99.7 g>
Isophthalic acid 40 mol% (66,51?
) 2 to 2 ethylene glycol 80 mol% (49.6 g)
Diol (I) (same as Synthesis Example 1) 40 mol% (I60.0g) The component composition other than the diol component and the reaction conditions were the same as in Synthesis Example 1 to obtain Polyester Resin-3. This resin had a molecular weight of 20,000 and a glass transition point of 35°C.

was polycondensed.

Terephthalic acid 60 mol% (99.7g)
Isophthalic acid 40 mol% (66.5g)
Ethylene glycol 80 mol% (49.6 g)
Bisphenol A 40 mol% (91.2 g
) Although the composition of components other than the diol component and the reaction conditions were the same as in Synthesis Example 1, polymerization did not proceed and no polyester resin was obtained.

Hogan λL A thickness of 30μ on each side of high-quality paper with a basis weight of 64g/m2.
Using a sheet of paper laminated with a polyethylene resin layer of In as a support, paint of the following composition was applied on one side of the paper.
1 was coated at a solid coating weight of 5 g/I+12 and dried to form an image-receiving layer to produce an image-receiving sheet for a dye thermal transfer printer.

For coating with the dicarboxylic acid component and diol component of the following composition - Polyester resin-1 (Synthesis example 1) 100 Silicone resin 3 (Trademark: S■
3476, manufactured by Toray Silicone Co., Ltd.) Toluene 200 Methyl ethyl ketone 200 A color test pattern was printed on the dye thermal transfer receiving sheet obtained as above using a commercially available sublimation transfer color video printer (Hitachi VY-50). , its performance was evaluated as follows.

The evaluation items are sensitivity during printing, maximum density, and thermal fusion with the ink ribbon during printing.

In the sensitivity test, transferred color density was compared at low energy.

The color density of the image was measured using a Macbeth densitometer.

The heat fusion resistance was determined by printing a gradation pattern using the above-mentioned sublimation transfer color video printer and observing whether or not there was fusion between the ink ribbon and the image receiving sheet 1 to 1.

The test results are shown in Table 1.

Fruit-bl''^ The same operation as in Example 1 was performed. However, instead of paint 1, paint 2 having the following composition was used.

l≦= Amount (parts by weight) Polyester resin-2 (Synthesis example 2) 100 Silicone resin 3 (Trademark: 5
H3476, manufactured by Toray Silicone Co., Ltd.) Toluene 200 Methyl Ethyl Ketone 200 The test results are shown in Table 1.

Omizo Knee The same operation as in Example 1 was performed. However, Paint-2 having the following composition was used instead of Paint-1.

Roasted↑L21 Sei jt(if
Yagami Polyester Resin-1 (Synthesis Example 1) 100
Silicone resin 3 (trademark:
5H3476, manufactured by Toray Silicone Co., Ltd.) Crosslinking agent 1 (trademark: Coronate, manufactured by Nippon Polyurethane Industries) Toluene 200 Methyl ethyl ketone 200 The test results are shown in Table 1.

The same operations as in Example 1 were performed. However, Paint-4 having the following composition was used instead of Paint-1.

Paint-4 composition ff1 (tf
ii Nogami Polyester Resin-3 (Synthesis Example 2> 1
00 Silicone resin 3 (trademark: 5t (3476, manufactured by Toray Silicone Co., Ltd.) Crosslinking agent 1 (trade name: Coronate, manufactured by Nippon Polyurethane Industries) Toluene 300 Methyl ethyl ketone 300 test 1 - The results are shown in Table 1.

The same operation as in Example 1 was performed on ktJ PI. However, Paint-5 having the following composition was used instead of Paint-1.

Paint-5 1■
) Polyester Resin-3 (Synthesis Example 3) 100 Silicone Resin 3 (Trademark:
Table 1 shows the test results.

1 bird 1 The same operation as in Example 1 was performed. However, Paint-6 having the following composition was used instead of Paint-1.

Fukikori two colors Growth Polyester resin-3 (Synthesis example 3) Silicone resin (Trademark: 5H3476, (manufactured by Toray Silicone Co., Ltd.) crosslinking agent (Trademark Nicolonate, (manufactured by Nippon Polyurethane Industries) toluene Methyl ethyl ketone The test results are shown in Table 1.

00 00 00 Table 1 [Effects of the Invention] The sublimable dye thermal transfer image-receiving sheet of the present invention contains a novel copolymerized polyester resin as the main component of its image-receiving layer, thereby improving the transferred dye image. It has the features of high sensitivity, high color density, brightness, and excellent storage stability, making it highly practical.

Note: 5...Excellent 4...Good 3...Normal 2...Poor 1...Significantly poor

Claims (1)

[Scope of Claims] 1. A sheet-like support, and a sublimable dye thermal transfer image-receiving layer formed on at least one surface of the support and containing a polyester resin as a main component, wherein the polyester resin is , (A) Ethylene glycol, neopentyl glycol, and bisphenol A- represented by the following formula (I)
Alkylene oxide adducts: ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) [However, in the above formula, R^1 and R^2 are each independently selected from a hydrogen atom and a methyl group. , m and n each independently represent an integer of 1 or more that satisfies the following relational expression: 2≦(m+n)≦6], and (B) terephthalic acid and isophthalic acid. A sublimable dye thermal transfer image-receiving sheet characterized by being a copolycondensation product of a dicarboxylic acid component containing an acid and having a glass transition point of 65° C. or higher.