JP2011051136A - Resin composition for dye receiving layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for a dye receiving layer which can maintain a sufficient photographic print traveling performance while developing a high photographic printing density, and also which can form the dye receiving layer of a sheet to which an image is thermally transferred with excellent light and crack resistance. <P>SOLUTION: This resin composition for a dye receiving layer for a sheet to which an image is thermally transferred is characteristic in that: it contains a polymer (A) obtained by polymerizing a polymerizable monomer raw material including an aromatic monomer, and a styrenic thermoplastic elastomer (B). In addition, the content of the styrenic thermoplastic elastomer (B) is 10 to 70 pts.mass to 100 pts.mass of the polymer (A). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin composition for a dye receiving layer.

As a method for developing image information or the like on a thermal transfer sheet such as photographic paper, a thermal transfer method using a sublimation dye or a hot melt dye is known.
In the thermal transfer method, a thermal transfer sheet (such as an ink ribbon) on which a dye layer having a sublimation dye or a heat-melting dye is formed, and a thermal transfer sheet (for example, photographic paper) on which a dye receiving layer for receiving the dye is formed. The dye layer and the dye receiving layer are stacked so that they face each other, and heat is applied in the form of dots according to the image signal by a thermal head or the like, so that the dye in the dye layer sublimates or melts to form a dye on the thermal transfer sheet. Transfer to the receiving layer and an image is formed on the dye receiving layer.

The thermal transfer sheet includes a base material and a dye receiving layer formed on the base material. The dye receiving layer is a layer that receives the dye transferred from the thermal transfer sheet and maintains an image formed by the reception.
The dye receiving layer for the thermal transfer sheet is formed from vinyl chloride-vinyl acetate copolymer resin, acrylic resin, polyester resin, or the like.

  The heat transfer sheet is required to exhibit high printing density and excellent printing running property. Therefore, in designing a resin for forming the dye-receiving layer, conventionally, a resin having a glass transition temperature or higher is selected and used, or a resin having a relatively low glass transition temperature is used after being crosslinked.

However, with the recent increase in printing speed, the thermal transfer sheet tends to be subjected to an excessive heat load, and the above-described resin design makes it easy to fuse the thermal transfer sheet and the thermal transfer sheet. It was difficult to maintain running performance.
Therefore, it is necessary to use a resin having a high glass transition temperature in order to maintain printing runnability that can withstand a high printing speed. However, when a resin having a high glass transition temperature is used, the image density, light resistance, and bending resistance (crack resistance) of the heat-transferable sheet are likely to be lowered.

Methods have been proposed to solve these problems.
For example, a dye receiving layer transfer sheet having a dye receiving layer containing a copolymer of an acrylic monomer and / or a styrene monomer and a monomer containing a plastic segment has been proposed as a thermal transfer sheet capable of developing a high printing density. (For example, refer to Patent Document 1).

JP 2008-44378 A

  However, although the dye-receiving layer transfer sheet described in Patent Document 1 can exhibit a high printing density, it has been difficult to sufficiently satisfy printing running properties.

  The present invention has been made in view of the above circumstances, and can form a dye-receiving layer of a thermal transfer sheet that can maintain a high printing density while maintaining a high printing density and is excellent in light resistance and crack resistance. It aims at realization of the resin composition for dye receiving layers.

  As a result of intensive studies, the present inventors have obtained a polymer obtained by polymerizing a raw material containing an aromatic monomer excellent in printing density and light resistance, and imparts crack resistance and is compatible with the polymer. By using a styrene-based thermoplastic elastomer excellent in the above, it has been found that a resin composition for a dye receiving layer capable of forming a dye receiving layer that sufficiently reflects the characteristics of both and is excellent in printing running property can be obtained, The present invention has been completed.

That is, the resin composition for a dye-receiving layer of the present invention is a resin composition for a dye-receiving layer of a thermal transfer sheet, and is a polymer obtained by polymerizing a polymerizable monomer raw material containing an aromatic monomer. (A) and a styrene thermoplastic elastomer (B) are contained, and the content of the styrene thermoplastic elastomer (B) is 10 to 70 parts by mass with respect to 100 parts by mass of the polymer (A). It is characterized by being.
Moreover, it is preferable that the elongation rate of the said styrene-type thermoplastic elastomer (B) is 20 to 300%.
Furthermore, it is preferable that the glass transition temperature of the said polymer (A) is 45-80 degreeC.
Moreover, it is preferable that the said polymer (A) superposes | polymerizes the polymerizable monomer raw material which contains 60-100 mass% of aromatic monomers.

  According to the present invention, a resin composition for a dye-receiving layer that can form a dye-receiving layer of a heat-transferable sheet that exhibits a high printing density while maintaining sufficient print running properties and is excellent in light resistance and crack resistance. Is obtained.

Hereinafter, the present invention will be described in detail.
The resin composition for a dye receiving layer of the present invention (hereinafter simply referred to as “resin composition”) contains a polymer (A) and a styrene-based thermoplastic elastomer (B).
The dye receiving layer formed from the resin composition of the present invention is formed by selectively transferring a dye layer formed on a thermal transfer sheet such as an ink ribbon and receiving the transferred dye image. It is a layer that maintains the rendered image.

The polymer (A) is a polymer obtained by polymerizing a polymerizable monomer raw material containing an aromatic monomer.
An aromatic monomer is a monomer excellent in printing density and light resistance. Therefore, when the resin composition contains the polymer (A), the characteristics of the aromatic monomer can be reflected in the dye receiving layer formed from the resin composition.

Examples of aromatic monomers include styrene, vinyl toluene, vinyl benzoate, benzyl (meth) acrylate, phenoxyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, phenoxypolypropylene glycol (meth) acrylate, and fumarate. An acid monoester etc. are mentioned. Of these, styrene, benzyl (meth) acrylate, and phenoxyethylene glycol (meth) acrylate are preferable because they are inexpensive and can reduce manufacturing costs. These aromatic monomers may be used alone or in combination of two or more.
In the present invention, “(meth) acrylate” refers to both methacrylate and acrylate.

The polymer (A) may be a homopolymer of an aromatic monomer, or a copolymer of an aromatic monomer and a monomer copolymerizable with the aromatic monomer. It may be a polymer.
An acrylic monomer is mentioned as a monomer copolymerizable with an aromatic monomer. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate , Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycidyl (meth) acrylate, methoxypolyethylene glycol ( (Meth) acrylate, methoxypolypropyleneethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate polypropylene ethylene glycol (meth) acrylate , Butoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and (meth) acrylic acid. These acrylic monomers may be used alone or in combination of two or more.

  In addition to acrylic monomers, monomers that can be copolymerized with aromatic monomers include vinyl acetate, maleic acid monoester, itaconic acid monoester, crotonic acid monoester, etc. It can also be used as long as the characteristics of the monomer are not impaired.

The content of the aromatic monomer is preferably 60 to 100% by mass in 100% by mass of the polymerizable monomer raw material. If the content of the aromatic monomer is 60% by mass or more, the surface quality of the thermal transfer sheet provided with the dye-receiving layer formed from the resin composition of the present invention can be sufficiently ensured. Moreover, higher printing density can be expressed.
When the content of the aromatic monomer is 100% by mass, it means that the polymer (A) is a homopolymer of the aromatic monomer, and the most characteristic of the aromatic monomer. Can be expressed. However, if the polymer (A) is a copolymer of an aromatic monomer and the acrylic monomer described above, the glass transition temperature is arbitrarily set in addition to the characteristics of the aromatic monomer. The effect that it can do is also acquired.

The polymer (A) can be obtained by polymerizing a polymerizable monomer raw material containing an aromatic monomer. As a polymerization method, a known method can be used, and examples thereof include suspension polymerization, solution polymerization, emulsion polymerization, and bulk polymerization.
The polymer (A) thus obtained preferably has a glass transition temperature (Tg) of 45 to 80 ° C, more preferably 50 to 70 ° C. When Tg is 45 ° C. or higher, the thermal transfer sheet can be effectively prevented from fusing when transferring the image by overlaying the thermal transfer sheet with the obtained dye-receiving layer on the thermal transfer sheet. It becomes excellent in nature. On the other hand, when Tg is 80 ° C. or lower, high print density, light resistance, and crack resistance can be maintained satisfactorily.

  The Tg of the polymer (A) is measured according to JIS K7121. Specifically, first, the sample to be measured is heated for 10 minutes at a temperature about 50 ° C. higher than the predicted Tg (predicted temperature) of the sample using a differential scanning calorimeter (manufactured by Shimadzu Corporation, “DSC-60A”). Then, it is cooled to a temperature lower by 50 ° C. than the predicted temperature and pretreated. Thereafter, in a nitrogen atmosphere, the temperature is increased at a rate of temperature increase of 10 ° C./min, and the endothermic start temperature is measured.

  47-91 mass% is preferable in 100 mass% of resin compositions, and, as for content of a polymer (A), 59-91 mass% is more preferable. When the content of the polymer (A) is 47% by mass or more, a resin composition capable of forming a dye receiving layer excellent in printing density, printing running property, and light resistance can be obtained. On the other hand, if content of a polymer (A) is 91 mass% or less, the resin composition which can form the dye receiving layer excellent in crack resistance will be obtained.

As described above, the polymer (A) is obtained by homopolymerizing or copolymerizing an aromatic monomer having excellent printing density and light resistance. Therefore, the polymer (A) is a component that plays a role of reflecting the characteristics (that is, printing density and light resistance) of the aromatic monomer in the dye-receiving layer formed from the resin composition.
By the way, since the aromatic monomer component is likely to be fused with the binder resin of the thermal transfer sheet, the printing runnability may not be sufficiently exhibited.
Thus, as a result of intensive studies, the present inventors have sufficiently used the following styrene-based thermoplastic elastomer (B) to sufficiently improve the characteristics of the aromatic monomer while supplementing crack resistance and printing runnability. It was found that it can be expressed.

  Styrenic thermoplastic elastomer (B) is an elastomer that can impart crack resistance. In addition, since the compatibility with the polymer (A) is excellent, the properties of both the polymer (A) and the styrene-based thermoplastic elastomer (B) are sufficiently reflected when used in combination with the polymer (A). A resin composition capable of forming a dye-receiving layer is obtained. In particular, printing runnability is not sufficiently exhibited by the single use of the polymer (A), but the combined use of the polymer (A) and the styrenic thermoplastic elastomer (B) allows the dye receiving layer at the time of printing to be used. Since the fusion of the thermal transfer sheet to the binder resin due to the thermal melting is suppressed, it is possible to sufficiently develop.

  The styrene-based thermoplastic elastomer (B) preferably has an elongation of 20 to 300%, more preferably 40 to 250%. If the elongation percentage is 20% or more, rubber elasticity can be imparted to the dye receiving layer to be formed, so that sufficient printing runnability and crack resistance can be exhibited. On the other hand, if the elongation is 300% or less, excessive plasticization of the dye-receiving layer can be prevented, the printing runnability can be maintained well, and the blocking resistance is also excellent.

  The elongation percentage of the styrene-based thermoplastic elastomer (B) is measured in accordance with JIS K7161 (ISO 527-1). Specifically, using a fracture toughness tester, the measured value when measured at a test speed of 50 mm / min is defined as the elongation.

  The styrene-based thermoplastic elastomer (B) preferably has a styrene content of 30 to 70% by mass. If styrene content is 30 mass% or more, compatibility with a polymer (A) can fully be ensured, and it can suppress that the surface quality of a photographic paper deteriorates. On the other hand, if the styrene content is 70% by mass or less, sufficient crack resistance and printing runnability can be exhibited.

  The styrene content of the styrenic thermoplastic elastomer (B) is measured using a nuclear magnetic resonance apparatus. Specifically, it can be calculated by dissolving the styrene-based thermoplastic elastomer (B) in deuterated chloroform, measuring using a nuclear magnetic resonance apparatus, and quantifying the proportion of benzene rings.

  The styrene thermoplastic elastomer (B) preferably has a mass average molecular weight of 30,000 to 300,000, more preferably 50,000 to 170,000. When the mass average molecular weight is 30000 or more, sufficient printing runnability can be imparted to the dye receiving layer to be formed. On the other hand, when the mass average molecular weight is 300000 or less, the compatibility with the polymer (A) is sufficiently maintained, and deterioration of the image quality of the formed dye receiving layer can be suppressed.

  The mass average molecular weight of the styrene-based thermoplastic elastomer (B) is a value measured by gel permeation chromatography. Specifically, tetrahydrofuran (THF) was used as the mobile phase, and measurement was performed with a gel permeation chromatograph under conditions of a flow rate of 1.0 mL / min.

  Examples of such a styrenic thermoplastic elastomer (B) include a styrene-butadiene block copolymer (SBS: polystyrene-block-polybutadiene-block-polystyrene copolymer) and a hydrogenated styrene-butadiene block copolymer (SEBS: polystyrene-block). -Poly (ethylene-co-butylene) -block-polystyrene copolymer), partially hydrogenated styrene-butadiene block copolymer (SBBS: polystyrene-block-poly (butadiene-butylene) -block-styrene copolymer), styrene- And isoprene block copolymer (SIS: polystyrene-block-polyisoprene-block-polystyrene copolymer).

Moreover, a commercial item can be used as these styrene-type thermoplastic elastomers (B).
Examples of the styrene-butadiene block copolymer include tufprene A, tufprene 125, tufprene 126S, tufprene 315P, tufprene 912, asaprene T-411, asaprene T-412, asaprene T-413, asaprene T-420, asaprene T-432, asaprene. J-TR TR1086 JSR TR1600, JSR TR2000, JSR TR2003, JSR TR2250, JSR TR2601, JSR TR2787, JSR TR2827 (above, JSR Include the formula company, Ltd.), and the like.
Examples of the hydrogenated styrene-butadiene block copolymer include Tuftec H1031, Tuftec H1041, Tuftec H1043, Tuftec H1051, Tuftec H1052, Tuftec H1053, Tuftec H1062, Tuftec H1141, Tuftech H1211, Tuftech H1272, Tuftec M1913, Tuftec M1913, As above, manufactured by Asahi Kasei Chemicals Corporation); AR-130, AR-140, AR-160, AR-170, AR-710, AR-720, AR-731, AR-741, AR-750, AR-760, AR -770, AR-781, AR-791 (above, Aron Kasei Co., Ltd.) and the like.
Examples of the partially hydrogenated styrene-butadiene block copolymer include Tuftec MP10, Tuftec P1500, Tuftec P2000 (manufactured by Asahi Kasei Chemicals Corporation), and the like.
Examples of the styrene-isoprene block copolymer include JSR SIS5200, JSR SIS5202, JSR SIS5405, JSR SIS5505 (manufactured by JSR Corporation); Etc.

  Content of a styrene-type thermoplastic elastomer (B) is 10-70 mass parts with respect to 100 mass parts of polymers (A), and 10-60 mass parts is preferable. When the content of the styrene-based thermoplastic elastomer (B) is 10 parts by mass or more, sufficient printing runnability and crack resistance can be exhibited. The styrene thermoplastic elastomer (B) is excellent in compatibility with the polymer (A), but if the styrene thermoplastic elastomer (B) is excessive, the compatibility tends to be lowered. If the content of the styrenic thermoplastic elastomer (B) is 70 parts by mass or less, the compatibility with the polymer (A) can be maintained well, and deterioration of the surface quality of the heat-transferable sheet can be suppressed, Excellent print density and light resistance can be expressed.

The resin composition may contain other polymers and additives other than the polymer (A) and the styrene-based thermoplastic elastomer (B) as long as the effects of the present invention are not impaired. Examples of other polymers include polyester resins, fiber-based resins, vinyl chloride-vinyl acetate copolymer resins, and urethane resins. When other polymers are contained, the content is preferably 5 to 25 parts by mass with respect to 100 parts by mass in total of the polymer (A) and the styrene-based thermoplastic elastomer (B).
Moreover, as an additive, a leveling agent, an antifoamer, etc. are mentioned, for example. When the additive is contained, the content is preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass in total of the polymer (A) and the styrene-based thermoplastic elastomer (B).

The resin composition can be prepared by uniformly dissolving or dispersing the above-described polymer (A) and styrene-based thermoplastic elastomer (B), and, if necessary, other polymers and additives in a solvent.
Examples of the solvent include toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, water and the like.

When forming a dye receiving layer using a resin composition, it is preferable to apply a resin composition so that the film thickness after drying may be 1-20 micrometers, More preferably, it is 2-10 micrometers. When the film thickness is 1 μm or more, high print density and light resistance can be maintained. On the other hand, if the thickness is 20 μm or less, a decrease in crack resistance can be suppressed.
Examples of the method for applying the resin composition include a roll coating method, a bar coating method, a gravure coating method, and a gravure reverse method.

Since the resin composition of the present invention described above contains the polymer (A) and the styrenic thermoplastic elastomer (B) described above, characteristics of both (ie, high print density, light resistance, crack resistance). ) Can be sufficiently reflected.
By the way, if the printing performance of the dye-receiving layer is poor, the thermal transfer sheet is not easily peeled off from the thermal transfer sheet, and when it is peeled off, a sound called a printing sound may be produced, which may be unpleasant. Therefore, the presence or absence of printing sound is an indicator of printing running property, but if the resin composition of the present invention is used, excellent printing can be achieved by using the polymer (A) and the styrene thermoplastic elastomer (B) in combination. Since the running property can be expressed, it is difficult to hear the printing sound when transferring the image.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these.
Here, the polymer (A) and the styrene-based thermoplastic elastomer (B) used in each example are shown below.

<Polymer (A)>
(Preparation of polymer (A-1))
In a 3 L flask equipped with a stirrer, a condenser, and a thermometer, 1600 parts by mass of pure water, 8 parts by mass of tricalcium phosphate, sodium alkylnaphthalene sulfonate as a dispersing agent (manufactured by Kao Corporation, “Perex BNL”) 0.1 A mass part was charged, and the mixture was stirred under a stirring speed of 600 rpm.
Separately, in a 1 L flask equipped with a stirrer, a condenser and a thermometer, 560 parts by mass of styrene, 200 parts by mass of benzyl acrylate and 40 parts by mass of butyl acrylate as a raw material for the polymerizable monomer, and benzoyl peroxide as a polymerization initiator 0.2 parts by mass was charged, and nitrogen was passed for 10 minutes while stirring to prepare a monomer mixed solution.
Next, the monomer mixed solution was poured into the previous 3 L flask and suspended by stirring for 10 minutes. Thereafter, the temperature of the hot water bath was raised to 75 ° C., and a polymerization reaction was carried out under conditions of 75 ° C. × 10 hours. Then, it cooled to 40 degrees C or less, and also added nitric acid 3mL, and stirred for 30 minutes.
The contents of the flask were washed by passing water through a centrifugal dehydration washer, then dehydrated and dried overnight at 50 ° C. to obtain a polymer (A-1). The polymer (A-1) had properties with a volatile content of 1% by mass.
Moreover, the glass transition temperature (Tg) and mass average molecular weight of the obtained polymer (A-1) were measured by the method shown below. The results are shown in Table 1.

(Measurement of Tg)
Tg of the polymer (A-1) was measured according to JIS K7121. Specifically, first, the polymer A-1 was measured by using a differential scanning calorimeter (“DSC-60” manufactured by Shimadzu Corporation) at a temperature about 50 ° C. higher than the predicted Tg (predicted temperature) of the sample. After heating for a minute, it was cooled to a temperature 50 ° C. lower than the predicted temperature and pretreated. Thereafter, the temperature was increased at a rate of temperature increase of 10 ° C./min in a nitrogen atmosphere, and the endothermic start temperature was measured, which was defined as Tg.

(Measurement of mass average molecular weight)
The mass average molecular weight of the polymer (A-1) was measured by the gel permeation chromatography method under the following conditions, and a value converted to polystyrene was defined as the mass average molecular weight.
Apparatus: “GPC-101” manufactured by Shoko Tsusho Corporation,
Column: Two "Column TSK-Gel GMH" manufactured by Tosoh Corporation and "Column TSK-Gel G2000H" x 1 manufactured by Tosoh Corporation
Mobile phase: tetrahydrofuran (THF),
Flow rate: 1.0 mL / min.

(Preparation of polymers (A-2) to (A-5))
Except having changed the kind of each monomer, and its compounding quantity (mass part) so that a composition of a polymerizable monomer raw material may come to show in Table 1, it carries out similarly to a polymer (A-1). Polymers (A-2) to (A-5) were prepared. Table 1 shows the Tg and the weight average molecular weight of each polymer.

Moreover, the compound shown below was used instead of the polymer (A).
Polyester resin: “Byron # 200” manufactured by Toyobo Co., Ltd., Tg: 67 ° C., mass average molecular weight: 17000.
-Vinyl chloride resin: vinyl chloride-vinyl acetate copolymer resin, “Solvine C5R” manufactured by Nissin Chemical Industry Co., Ltd., Tg: 68 ° C., mass average molecular weight: 27000.

<Styrenic thermoplastic elastomer (B)>
B-1: Styrene-butadiene block copolymer.
B-2: Styrene-butadiene block copolymer.
B-3: Styrene-butadiene block copolymer.
B-4: Styrene-butadiene block copolymer.
B-5: Styrene-butadiene block copolymer.
B-6: Partially hydrogenated styrene-butadiene block copolymer.
B-7: Partially hydrogenated styrene-butadiene block copolymer.
Moreover, the compound shown below was used instead of the styrene-type thermoplastic elastomer (B).
Polybutadiene rubber: “Kuraprene LBR-300” manufactured by Kuraray Co., Ltd.

In addition, the styrene content, elongation rate, and mass average molecular weight of B-1 to B-7 and polybutadiene rubber were measured by the following methods. The results are shown in Table 2.
(Styrene content)
The styrene content was calculated by dissolving a measurement sample in deuterated chloroform and using a nuclear magnetic resonance apparatus (“R-1200” manufactured by Hitachi, Ltd.) to quantify the proportion of benzene rings.
(Measurement of elongation)
The elongation was measured according to JIS K7161 (ISO 527-1). Specifically, using a fracture toughness tester, the measured value when measured at a test speed of 50 mm / min was defined as the elongation.
(Measurement of mass average molecular weight)
The mass average molecular weight was measured in the same manner as for polymer A-1.

[Example 1]
<Preparation of resin composition>
100 parts by mass of A-1 as a polymer (A) and B-5 as a styrenic thermoplastic elastomer (B) are dissolved in 220 parts by mass of methyl ethyl ketone (MEK) and 220 parts by mass of toluene to obtain a resin composition. A product coating solution (non-volatile content 20% by mass) was prepared.

<Preparation of photographic paper>
On the base material (white PET film), the obtained coating solution was applied with a # 18 coil bar so that the thickness of the dye-receiving layer after drying was 5 μm, and dried at 120 ° C. for 3 minutes. A photographic paper having a dye-receiving layer formed thereon was obtained.
The following evaluation was performed on the obtained photographic paper. The results are shown in Table 3. For each evaluation, “◯” and “Δ” are accepted and “x” is rejected.

<Evaluation>
(Evaluation of image quality)
The surface of the photographic paper was visually observed, and the image quality was evaluated according to the following evaluation criteria.
○: Reflected image is clear and has good gloss.
Δ: Reflected image is slightly unclear, but gloss is maintained.
X: The surface gloss is poor.

(Measurement of print density)
Print black on a photographic paper with a sublimation type thermal transfer printer (manufactured by Sony Corporation, “DR-150”), and measure the density of the solid black part using a Macbeth reflection densitometer (“Spectaeye UV” manufactured by GretagMacbeth). The print density was evaluated according to the following evaluation criteria.
○: The concentration is 1.95 or more.
(Triangle | delta): A density | concentration is 1.80 or more and less than 1.95.
X: The density is less than 1.80.

(Evaluation of printing runnability)
The photographic paper was solid black printed with a sublimation type thermal transfer printer (manufactured by Sony Corporation, “DR-150”). The printing sound generated at that time and the fusing marks of the dye layer (dye ribbon) on the dye receiving layer (printing paper) were visually observed, and the print running property was evaluated according to the following evaluation criteria.
○: No print sound can be heard and no fusing marks can be confirmed.
Δ: A print sound can be heard, but no fusing marks are observed.
X: The printing sound can be clearly heard, and a part of the fusion mark can be confirmed on the printing paper.

(Evaluation of crack resistance)
Using a mandrel bending tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), holding a roll bar having a mandrel diameter of 16 mm, the photographic paper was bent at room temperature (23 ° C.). The surface of the photographic paper after bending was visually observed and observed for cracks with a 50 × optical microscope, and the crack resistance was evaluated according to the following evaluation criteria.
○: No cracks can be confirmed by visual observation or observation with an optical microscope.
Δ: Cracks cannot be visually recognized by visual observation, but cracks can be confirmed by optical microscope observation.
X: A crack can be visually recognized by visual observation.

(Evaluation of blocking resistance)
Two photographic papers were superposed and left for 24 hours in a 60 ° C. environment while applying a pressure of 0.75 kg / cm ² . The subsequent two photographic papers were evaluated for blocking resistance according to the following evaluation criteria.
○: The two photographic papers are not attached at all (not blocked).
Δ: The two photographic papers are stuck but easily peeled off.
X: The two photographic papers are fused and do not peel off.

(Evaluation of light resistance)
A weather resistance test was performed by irradiating the photographic paper with a xenon lamp (with a 300 nm cut filter) under the conditions of an illuminance of 40000 LUX and an irradiation time of 60 hours. Before and after the irradiation, a color difference (ΔE) was measured for each of magenta (M), yellow (Y), cyan (C), and black (Bk) using a Macbeth reflection densitometer (manufactured by GretagMacbeth, “SpectroEye UV”). The light resistance was evaluated according to the following evaluation criteria.
○: The sum of ΔE of M, Y, C, and Bk is less than 11.
Δ: The sum of ΔE of M, Y, C, and Bk is 11 or more and less than 13.
X: The sum of ΔE of M, Y, C, and Bk is 13 or more.

[Examples 2-11, Comparative Examples 1-8]
As the polymer (A) and the styrenic thermoplastic elastomer (B), compounds of the types and blending amounts (parts by mass) shown in Tables 3 and 4 are used, and the blending amounts (parts by mass) of the solvents are shown in Tables 3 and 4. Except for the above changes, a resin composition was prepared in the same manner as in Example 1, photographic paper was prepared, and each evaluation was performed. The results are shown in Tables 3 and 4.

As is apparent from Table 3, the photographic paper provided with the dye-receiving layer obtained from the resin composition of each example can maintain a high printing density while maintaining sufficient printing runnability, and is light resistant. Excellent crack resistance. It also had excellent image quality and blocking resistance.
In addition, in the case of Example 7 using the styrene-type thermoplastic elastomer (B-1) having an elongation rate of 15%, the print running property and crack resistance were slightly inferior to those of Examples 1 to 6.
In the case of Example 8 using the styrene thermoplastic elastomer (B-6) having an elongation of 780%, the print running property and the blocking resistance were slightly inferior to those of Examples 1-6.
In the case of Example 9 using the polymer (A-2) having a glass transition temperature of 40 ° C., the print running property and the blocking resistance were slightly inferior to those of Examples 1-6.
In Example 9 using the polymer (A-3) having a glass transition temperature of 85 ° C., the printing density, crack resistance, and light resistance were slightly inferior to those of Examples 1-6.
In the case of Example 11 using the polymer (A-4) in which the ratio of the aromatic monomer in the polymerizable monomer raw material is 50% by mass, the printing density is slightly higher than those in Examples 1 to 6. It was inferior.

On the other hand, as is clear from Table 4, in the case of Comparative Example 1 in which the content of the styrene-based thermoplastic elastomer (B) is 5 parts by mass, the print running property and crack resistance were inferior to those of the Examples. .
In the case of Comparative Example 2 in which the content of the styrene-based thermoplastic elastomer (B) was 80 parts by mass, the image quality was inferior to each example. Further, compared with Examples 2, 4, 6, and 8, the printing density and light resistance were also inferior.
In the case of the comparative example 3 which does not contain a styrenic thermoplastic elastomer (B), the printing running property and the crack resistance were inferior to those of the examples. Moreover, it was inferior also to light resistance compared with Example 1, 3, 5, 7.
In the case of Comparative Examples 4 and 6 in which a polyester resin or a vinyl acetate resin is used instead of the polymer (A) and the styrenic thermoplastic elastomer (B) is not contained, the print running property and the light resistance are compared with those in each example. It was inferior. In particular, in Comparative Example 4 using a polystyrene resin instead of the polymer (A), the crack resistance and blocking resistance were slightly inferior.
In the case of the comparative example 5 which used the polyester resin instead of the polymer (A), the image quality and light resistance were inferior compared with each Example. Moreover, compared with Example 3, it was inferior also in printing running property, crack resistance, and blocking resistance.
In the case of Comparative Example 7 using a vinyl acetate resin instead of the polymer (A), the image quality, the print running property, and the light resistance were inferior to those of the Examples. Moreover, compared with Example 2, the printing density and the blocking resistance were also inferior.
In the case of Comparative Example 8 in which polybutadiene rubber was used instead of the styrene-based thermoplastic elastomer (B), the image quality, printing density, printing runnability, crack resistance, and light resistance were inferior to those of the Examples.

Claims (4)

A resin composition for a dye receiving layer of a thermal transfer sheet,
Containing a polymer (A) obtained by polymerizing a polymerizable monomer raw material containing an aromatic monomer, and a styrene-based thermoplastic elastomer (B);
Content of the said styrenic thermoplastic elastomer (B) is 10-70 mass parts with respect to 100 mass parts of said polymers (A), The resin composition for dye receiving layers characterized by the above-mentioned.   The resin composition for a dye-receiving layer according to claim 1, wherein the elongation percentage of the styrene-based thermoplastic elastomer (B) is 20 to 300%.   The resin composition for a dye-receiving layer according to claim 1 or 2, wherein the polymer (A) has a glass transition temperature of 45 to 80 ° C. The dye acceptor according to any one of claims 1 to 3, wherein the polymer (A) is obtained by polymerizing a polymerizable monomer raw material containing 60 to 100% by mass of an aromatic monomer. Layer resin composition.