JP2998219B2 - Dye thermal transfer image receiving sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dye thermal transfer image receiving sheet. More specifically, the present invention is capable of dyeing and receiving a full-color image with a sublimable or heat-diffusible dye, and the resulting image has high density, sharpness, and has excellent heat resistance and light stability. It relates to an excellent dye thermal transfer image receiving sheet.

[0002]

2. Description of the Related Art In recent years, printers for obtaining high-quality color hard copies obtained by a thermal transfer method, particularly dye thermal transfer printers, have been rapidly developed.

In a dye thermal transfer printer, sublimable dye layers of three colors (yellow, magenta, and cyan) are formed on an ink sheet, respectively, and heated while continuously controlling the thermal energy of a thermal head. By this, while changing the transfer amount of the dye of each color, this is transferred on the image receiving sheet,
It is possible to form a full-color image of a density gradation.

In order to obtain a high quality image on an image receiving sheet, the transfer sensitivity of the dye is high and the dyeing amount is large.
In addition, the printed image has excellent durability against heat, light, and the like, and therefore, it is necessary to form an image receiving layer having good image storability.

[0005] The dye thermal transfer image receiving sheet has an image receiving layer, which is mainly composed of a thermoplastic resin capable of dyeing and receiving the dye transferred from the ink sheet. In order to improve the sensitivity of the dye, it is necessary to further increase the transfer speed and the dyeing amount of the dye.

Further, in order to improve the preservability, it is necessary to have good dye retention under various preservation conditions.

Conventionally, transfer speed and dyeing amount are relatively large,
Various polyester resins have been known as dye-receiving resins having excellent image storability.

For example, JP-A-63-159089 proposes lowering the glass transition point of a dye-receiving resin in order to obtain a resin having a high transfer speed and / or a large amount of dyeing.

That is, in polyethylene terephthalate, which is a polycondensation product of a glycol component composed of ethylene glycol and a dicarboxylic acid component composed of terephthalic acid, in order to lower the glass transition point, different types of glycols and dicarboxylic acids are used. It has been attempted to copolymerize the above components.

However, when the glass transition point is lowered, the transfer speed and / or the amount of dyeing of the obtained resin are increased, but the strength of the obtained image receiving layer at high temperatures is lowered, and the resin is fused to the ink ribbon. In addition, bleeding of the dye due to heating or the like occurs during storage of the printed image.

In addition, when the coating material for the image receiving layer is applied to a substrate, dried and wound up in a roll form, there is also a problem in production such as blocking.

Therefore, in order to obtain a dyeable resin having excellent storage properties, it is necessary to raise the glass transition point of the resin, contrary to the above-mentioned attempt. The amount of dyeing will be reduced.

JP-A-2-81673 discloses a polyester resin using bisphenol A adduct of ethylene oxide and propylene oxide as an alcohol component.

This polyester resin has the advantages of a high glass transition point and high dyeing properties, but has the disadvantage that the printed image is easily discolored by light.

For this reason, there has been a demand for the development of a dye thermal transfer image receiving sheet having an image receiving layer having high dyeing properties, high durability against heat and light, and good storage stability.

[0016]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, and has high transfer sensitivity of a dye, high density of a printed image, excellent durability against heat and light, and generation of blocking due to heating. The purpose of the present invention is to provide a dye heat transfer image receiving sheet that does not use the dye.

[0017]

The present inventors have made intensive efforts to solve the above-mentioned problems, and as a result, have used a special glycidyl compound as at least a part of a glycol component as a dye-receiving resin for forming an image-receiving layer. By using the specific polyester resin obtained as described above, the above problem has been successfully solved.

That is, the dye thermal transfer receiving sheet of the present invention has a sheet-like support, and an image receiving layer formed on at least one surface of the support and containing a dye-receptive resin as a main component. (A) a carboxylic acid component containing at least one ester-forming aromatic dicarboxylic acid compound as a main component, and (B) a glycol component in an equimolar amount to the carboxylic acid component (A). And (i) phenylglycidyl ether, p-tert-butylphenylglycidyl ether, p-α-cumylphenylglycidyl ether, p-tert- in the glycol component (B). Butylphenyl glycidyl ester, glycidyl phthalimide, α-
5 mol% or more of a glycidyl compound component composed of at least one selected from naphthyl glycidyl ether, β-naphthyl glycidyl ether, and triphenylmethyl glycidyl ether: (ii) 95 composed of at least one ester-forming glycol compound The product of the polycondensation reaction of the component (A) and the component (B) is a polyester resin modified with the glycidyl compound component (i), which is used in combination with a mole% or less of a glycol compound component. It is characterized by the following.

[0019]

The image-receiving layer made of the above-mentioned specific polyester resin solves the above-mentioned drawbacks, and has a high thermal transfer sensitivity of the dye, a high image density, excellent heat and light preservability, and a high glass transition point. Therefore, it is possible to provide a dye thermal transfer image receiving sheet which does not cause problems such as blocking during production.

The image receiving sheet in which the sensitivity and the amount of dyeing of the image receiving layer are improved by lowering the glass transition point of the polyester resin can be used to prevent running problems such as fusing and the like.
Although the undesired results such as a decrease in preservability and blocking during production are caused, in the present invention, the above-mentioned drawbacks are avoided by using the above-mentioned special phenylglycidyl compound as a glycol component of the dyeable polyester resin. This special dye-accepting resin has a high dissolution acceptability upon heating with respect to a dye supplied from an ink sheet and has a glass transition point higher than room temperature.

The reason why the polyester resin modified with the glycidyl compound of the present invention (hereinafter referred to as an epoxy-modified polyester resin) exhibits high dye receptivity and anti-blocking property is not clear, but is presumed as follows. That is, the conventional polyester has an aromatic ring incorporated in the polymer skeleton. In the epoxy-modified polyester resin of the present invention, when an aromatic dicarboxylic acid is used as the dicarboxylic acid component, an aromatic cyclic structure derived from the aromatic carboxylic acid is incorporated into the main skeleton of the polymer. It is considered that the aromatic cyclic structure derived from the group-containing glycidyl compound is branched. It is presumed that the polymer structure having such characteristics improves the diffusibility of the dye, and as a result, enhances the dyeing property and further contributes to the improvement of the anti-blocking property. Based on such a concept, it is expected that the above effects can be obtained by using an aromatic compound containing a glycidyl group together with a glycol compound in a glycol component.

The epoxy-modified polyester resin of the present invention comprises at least one kind of the above-mentioned glycidyl group-containing compound in an amount of 5 mol% or more of the phenylglycidyl compound component (i) and at least one kind of glycol compound.
A glycol component (B) comprising 95 mol% or less of a glycol compound component (ii), and at least one ester-forming aromatic dicarboxylic acid compound in an equimolar amount to the glycol component (B). It is a polycondensation product with the carboxylic acid component (A).

The aromatic dicarboxylic acid compounds include terephthalic acid, isophthalic acid, orthophthalic acid, and 2,6
-It is preferable to use an aromatic dicarboxylic acid such as naphthalenedicarboxylic acid.

The carboxylic acid component preferably contains an aromatic dicarboxylic acid in a content of at least 30 mol% or more.

The carboxylic acid component may contain dicarboxylic acids other than aromatic dicarboxylic acids, such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer. An aliphatic dicarboxylic acid such as an acid and an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid can also be used.

The carboxylic acid component may contain a small amount of a polyfunctional polycarboxylic acid. Examples of such a carboxylic acid component include aromatic carboxylic acids such as trimellitic acid and pyromellitic acid; Aliphatic polycarboxylic acids such as carboxylic acids can also be used.

The glycol component for producing the epoxy-modified polyester resin of the present invention comprises at least 5 mol% of a phenylglycidyl compound component (i) comprising at least one specific phenyl group-containing glycidyl compound, and at least one glycol. And a glycol compound component (ii) in a residual amount (95 mol% or less) of the compound.

The glycol compound used in the component (ii) is an aliphatic glycol such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, diethylene glycol, dipropylene glycol, and neopentyl glycol; aromatic glycols, such as ethylene and propylene oxide adducts of bisphenol A; and alicyclic glycols, such as 1,4
It can be selected from cyclohexanedimethanol and the like.

Such a glycol compound component (ii)
Is used in an amount that does not adversely affect the storability of the dye image on the resulting image receiving layer.

In the production of the epoxy-modified polyester resin of the present invention, the dicarboxylic acid component and the glycol component
Used in equimolar amounts.

The glycol component contains 5 mol% or more of the glycidyl compound component and 95 mol% or less of the glycol compound component in combination. The amount of the glycidyl compound component in the glycol component is 5 mol%
When the amount of the glycol compound component is more than 95 mol%, the anti-blocking property of the obtained dye thermal transfer image receiving sheet can be clearly seen from the comparison between Comparative Example 1 in Table 1 and Examples 1-4. Is significantly poorer, and its heat resistance is lower than that of the present invention.

The glycidyl compound used in the present invention is
Phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, p-α-cumylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ester, glycidyl phthalimide, α-naphthyl glycidyl ether, β-naphthyl glycidyl ether, and triphenyl Selected from methyl glycidyl ether.

The molecular weight of the epoxy-modified polyester resin of the present invention is preferably at least 2,000, more preferably at least 5,000, and its glass transition point is 40 ° C.
Or more, more preferably 60 ° C. or more.

The epoxy-modified polyester resin used in the present invention may be used alone or in a small amount (30% by weight or less) of other polyester resins, acrylic resins, vinyl acetate resins, vinyl chloride resins. It may be used by mixing with another thermoplastic resin such as phenoxy resin or a synthetic resin soluble in a solvent.

In the image receiving sheet of the present invention, for the purpose of preventing thermal fusion with the ink sheet at the time of printing, modified silicone such as silicone oil, epoxy-modified silicone, alcohol-modified silicone, etc. A release agent containing silicone varnish, paraffin, waxes such as polyethylene wax, or a phosphoric ester may be added.
% (Weight).

If the amount of the release agent exceeds 10%, the adhesiveness between the image receiving layer and the substrate may be impaired, and if it is less than 0.1%, the effect of preventing heat fusion is not sufficient. .

The resin in the image-receiving layer of the present invention may be cross-linked with a cross-linking agent for improving its heat-resistant storage stability and heat-resistant fusion property.

It is preferable that such a cross-linking agent is selected from those capable of cross-linking with a group having active hydrogen, such as a hydroxyl group, in the epoxy-modified polyester resin molecule of the present invention.

As such a crosslinking agent, for example, a polyfunctional isocyanate compound is used. Examples of such polyfunctional isocyanates include tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate.

In addition, it is possible to use a crosslinking agent such as an epoxy group-containing compound, an aziridine compound, a melamine resin or a urea resin as long as the dye receptivity of the obtained image receiving layer is not adversely affected.

In general, if the amount of the cross-linking agent added is too large, the resin will be too cured, and the acceptability of the dye will be reduced, and the sensitivity will also be reduced.

For this reason, the amount of the crosslinking agent added is preferably 20% by weight or less of the weight of the image receiving layer, more preferably 10% by weight or less, but more preferably 1% by weight or more. When the amount is less than 1% by weight, the effect is generally not sufficient.

The image-receiving layer of the present invention can be blended with a low-molecular organic compound such as a substituted phenol or terpene for the purpose of preventing oxidation, absorbing ultraviolet light, sensitizing, and the like. Pigments for improving the color and opacity, fluorescent dyes for adjusting the color tone of the image receiving layer, and dyes such as blue and violet can be added as necessary.

It is convenient to mix the above-mentioned additives such as a white pigment, an ultraviolet absorber and a cross-linking agent with an epoxy-modified polyester resin which is a main component of the image-receiving layer and apply the mixture. Alternatively, it may be coated on or under the image receiving layer as another coating layer.

Generally, the thickness of the image receiving layer is from 1 to 20 g / m
Preferably ^2, and more preferably 4~10g / m ^2. If the thickness of the image receiving layer is too thin, the density and sensitivity of the image decrease, and the uniformity of the image deteriorates due to the limitation of coating accuracy. On the other hand, if it is too thick, the effect is saturated and not only is uneconomical, but also the strength of the image receiving layer is reduced.

An antistatic agent is added to the image receiving layer formed on at least one surface of the image receiving sheet in order to prevent the occurrence of static electricity and running trouble when the image receiving sheet runs in the printer. Or it may be applied as an undercoat layer, a back coat or the like under the image receiving layer or on the back surface of the sheet-like support.

As the antistatic agent, a nonionic, cationic or anionic surfactant or a polymer is used.

The sheet-like support used in the present invention may be a high-quality paper, a coated paper, or a synthetic paper comprising a mono- or biaxially stretched film containing polyolefin and an inorganic pigment as main components, depending on the use of the image receiving sheet. For example, various plastic films or composite laminated sheets thereof can be used.

As an example of the composite laminated sheet, polyethylene laminated on both sides of high quality paper or coated paper can be used.

The thickness of the support used in the present invention is from 20 to
It is preferably 250 μm, the basis weight of which is 20 to 250 g
/ M ² .

[0051]

The present invention will be described in more detail with reference to the following examples.

Synthesis Example 1 Synthesis of Epoxy-Modified Polyester Resin-1 From carboxylic acid component (A), phenyl group-containing glycidyl compound component (B)-(i) and glycol compound component (B)-(ii) having the following composition: An epoxy-modified polyester resin was manufactured.

Dicarboxylic acid component (A) Terephthalic acid 60 mol parts (99.7 g) Isophthalic acid 30 mol parts (66.5 g) Sebacic acid 10 mol parts (20.2 g) Phenyl group-containing glycidyl compound (B)-(i ) Glycol compound component (B)-(ii) 60 mol parts of ethylene glycol (37.6 g)
Neopentyl glycol 10 mol part (10.4 g)

To a mixture of the carboxylic acid component (A) and the glycol compound component (B)-(ii), a trace amount of tetra-n-
Butyl titanate was added as a catalyst, and a trace amount of triphenyl phosphite was added, and the reaction mixture was heated in a nitrogen atmosphere and heated to 150 ° C.

Next, a phenyl group-containing glycidyl compound component was added thereto, and the temperature of the reaction system was gradually increased to 220 ° C.
Temperature, held at this temperature for 2 hours, and 0.2 mmHg
While maintaining the following vacuum, the above reaction mixture was subjected to a polycondensation reaction at a temperature of 260 ° C. for 2 hours to remove unreacted ethylene glycol, thereby producing an epoxy-modified polyester resin-1.

The molecular weight (by GPC) of this resin was 23,300 and its glass transition point was 60 ° C.

Synthesis Example 2 Synthesis of Epoxy-Modified Polyester Resin-2 An epoxy-modified resin comprising the following components was produced. Carboxylic acid component (A) Terephthalic acid 60 mol parts (99.7 g) Isophthalic acid 30 mol parts (66.5 g) Sebacic acid 10 mol parts (20.2 g) Phenyl group-containing glycidyl compound component (B)-(i) Glycol compound component (B)-(ii) 60 mol parts of ethylene glycol (37.6 g) 10 mol parts of neopentyl glycol (10.4 g)

An epoxy-modified polyester resin-2 was obtained under the same reaction conditions as in the case of the epoxy-modified polyester resin-1. The molecular weight of this resin is 20,800,
Its glass transition point was 68 ° C.

Synthesis Example 3 Synthesis of Epoxy-Modified Polyester Resin-3 An epoxy-modified resin comprising the following components was prepared. Carboxylic acid component (A) Terephthalic acid 60 mol parts (99.7 g) Isophthalic acid 30 mol parts (66.5 g) Sebacic acid 10 mol parts (20.2 g) Phenyl group-containing glycidyl compound component (B)-(i) Glycol compound component (B)-(ii) 60 mol parts of ethylene glycol (37.6 g) 10 mol parts of neopentyl glycol (10.4 g)

The reaction conditions were the same as in the case of the epoxy-modified polyester resin-1 to obtain an epoxy-modified polyester resin-3. The molecular weight of this resin was 6000, and its glass transition point was 58 ° C.

Synthesis Example 4 Synthesis of Epoxy-Modified Polyester Resin-4 An epoxy-modified resin comprising the following components was produced.

The reaction conditions were the same as in the case of the epoxy-modified polyester resin-1 to obtain an epoxy-modified polyester resin-4. The molecular weight of this resin is 16,400,
Its glass transition point was 63 ° C.

Synthesis Example 5 Synthesis of Unmodified Polyester Resin-1 A polyester resin having the following composition was produced. Dicarboxylic acid component terephthalic acid 60 mole parts (99.7 g) isophthalic acid 30 mole parts (66.5 g) sebacic acid 10 mole parts (20.2 g) glycol component ethylene glycol 80 mole parts (49.7 g) neopentyl glycol 20 mole Part (20.8g)

The above dicarboxylic acid component and glycol component are heated together with a trace amount of a calcium naphthenate catalyst in a nitrogen atmosphere to 150 ° C., and the reaction mixture is kept at this temperature for 2 hours to react. Further, unreacted ethylene glycol was removed while performing a polycondensation reaction at 250 ° C. for 2 hours while maintaining a vacuum of 0.1 mmHg or less to obtain an unmodified polyester resin-1.

The molecular weight of this resin was 25,300, and its glass transition point was 52 ° C.

Example 1 A 150 g / m ² high-quality paper laminate of 30 μm of polyethylene on both sides was used as a base material, and on one side thereof, paint-1 having the following composition was coated with a solid content of 5 g. /
m ² and dried to form an image receiving layer,
An image receiving sheet for a dye thermal transfer printer was manufactured.

Paint-1 Epoxy-modified polyester resin-1 100 parts (weight) Silicone resin 3 parts (〃) (trademark: SH3476, manufactured by Toray Silicone Co., Ltd.) Polyisocyanate 10 parts (〃) (trademark: Coronate HX, Nippon Polyurethane Co., Ltd.) 200 parts of toluene (〃) 200 parts of methyl ethyl ketone (〃)

A test pattern was printed on the dye thermal transfer receiving sheet obtained as described above using a trial sublimation dye thermal transfer color video printer (VY-P1 manufactured by Hitachi, Ltd.).

Evaluation items for the obtained print include sensitivity of the image receiving layer at the time of printing, maximum image density,
The printed image was tested for light fastness and heat resistance. Each test result was evaluated on a five-point scale as described below. Excellent performance (5), good performance (4), general quality (3), poor performance (2), serious fault (1).

In the sensitivity test, the transfer density of the image in the low energy thermal transfer was compared, and the color density was measured with a Macbeth densitometer. In addition, the heat resistance test of the printed image
Heat treatment at 60 ° C for 100 hours, and its light resistance test is 50 ° C, 63% with a fade meter using a xenon light source.
A change in image density and a change in color tone due to irradiation treatment at RH were observed.

Further, receiving sheets were stacked on each other to confirm the blocking property at the time of production, and the receiving sheets were heated under a load of 0.8 kg / cm ² at 50 ° C. for 48 hours. The presence or absence of blocking was observed.

Table 1 shows the test results.

Example 2 The same operation as in Example 1 was performed. However, in order to form an image receiving layer, paint-2 having a solid content of 5 g having the following composition was used.
/ M ² .

Paint-2 Epoxy modified resin-2 100 parts (weight) Silicone resin 3 parts (〃) (trademark: SH3476, manufactured by Toray Silicone Co.) Polyisocyanate 10 parts (〃) (trademark: Coronate HX, Nippon Polyurethane Co., Ltd.) 200 parts of toluene (〃) 200 parts of methyl ethyl ketone (〃)

Table 1 shows the test results.

Example 3 The same operation as in Example 1 was performed. However, in order to form an image receiving layer, paint-3 having the following composition had a solid content of 5 g.
/ M ² .

Paint-3 Epoxy modified resin-3 100 parts (weight) Silicone resin 3 parts (〃) (trademark: SH3476, manufactured by Toray Silicone Co.) Polyisocyanate 10 parts (〃) (trademark: Coronate HX, Nippon Polyurethane Co., Ltd.) 200 parts of toluene (〃) 200 parts of methyl ethyl ketone (〃)

Table 1 shows the test results.

Example 4 The same operation as in Example 1 was performed. However, in order to form an image receiving layer, paint-4 having the following composition had a solid content of 5 g.
/ M ² .

Paint-4 Epoxy modified resin-4 100 parts (weight) Silicone resin 3 parts (〃) (trademark: SH3476, manufactured by Toray Silicone Co.) Polyisocyanate 10 parts (〃) (trademark: Coronate HX, Nippon Polyurethane Co., Ltd.) 200 parts of toluene (〃) 200 parts of methyl ethyl ketone (〃)

Table 1 shows the test results.

Comparative Example 1 The same operation as in Example 1 was performed. However, in order to form an image receiving layer, paint-5 having a solid content of 5 g having the following composition was used.
/ M ² .

Paint-5 Unmodified polyester resin-1 100 parts (weight) Silicone resin 3 parts (〃) (trademark: SH3476, manufactured by Toray Silicone Co., Ltd.) Polyisocyanate 10 parts (〃) (trademark: Coronate HX, Nippon Polyurethane Co., Ltd.) 200 parts of toluene (〃) 200 parts of methyl ethyl ketone (〃)

Table 1 shows the test results.

Comparative Example 2 The same operation as in Example 1 was performed. However, in order to form an image receiving layer, paint-6 having a solid content of 5 g having the following composition was used.
/ M ² .

Paint-6 Commercially available polyester 100 parts (weight) (trademark: Byron 290, manufactured by Toyobo Co., Ltd., molecular weight: 20,000, Tg: 77 ° C.) Silicone resin 3 parts (（) (trademark: SH3476, manufactured by Toray Silicone Co., Ltd.) Poly Isocyanate 10 parts (〃) (trademark: Coronate HX, manufactured by Nippon Polyurethane) 200 parts of toluene (〃) 200 parts of methyl ethyl ketone (〃)

Table 1 shows the test results.

[Table 1]

[0088]

The dye heat transfer image-receiving sheet of the present invention comprises:
By including a novel epoxy-modified polyester resin in the image receiving layer, the sensitivity at the time of transfer is high, the dyeing density of the image is high, it is clear, and the durability against heat and light is excellent, and the It eliminates blocking properties and is therefore extremely useful as an image receiving sheet for a dye thermal transfer printer.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A sheet-like support, comprising: an image-receiving layer formed on at least one surface of the support and containing a dye-receiving resin as a main component; A) a carboxylic acid component containing at least one ester-forming aromatic dicarboxylic acid compound as a main component; and (B) a polycondensation reaction of the carboxylic acid component (A) with an equimolar amount of a glycol component. In the glycol component (B), (i) phenylglycidyl ether, p-tert-butylphenylglycidyl ether, p-α-cumylphenylglycidyl ether, p-tert-butylphenylglycidyl ester, glycidylphthalimide, α −
5 mol% or more of a glycidyl compound component composed of at least one selected from naphthyl glycidyl ether, β-naphthyl glycidyl ether, and triphenylmethyl glycidyl ether: (ii) 95 composed of at least one ester-forming glycol compound Mol% or less of a glycol compound component, and the product of the polycondensation reaction of the component (A) and the component (B) is a polyester resin modified with the glycidyl compound component (i). A dye thermal transfer image receiving sheet characterized by the following.