JP2012148473A - Method of manufacturing thermal transfer receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superior thermal transfer receiving sheet having no printing defect caused by blocking generated in a manufacturing step of the thermal transfer receiving sheet without causing a fusion trouble with a dye thermal transfer sheet.SOLUTION: In a method of manufacturing a thermal transfer receiving sheet including a sheet-like support having cellulose pulp as the main component and an image receiving layer on one surface of the sheet-like support, the method of manufacturing the thermal transfer receiving sheet includes the steps of: coating an image receiving layer coating liquid including a water-dispersible or water-soluble resin and a crosslinking agent; and bringing an image receiving layer surface into contact with a roll heated to 50 to 200°C while holding an image receiving layer surface temperature at ≥30°C after forming the image receiving layer by performing drying by a dryer.

Description

  The manufacturing method of the thermal transfer receiving sheet of the present invention is a manufacturing method that does not cause blocking of the image receiving layer and the back surface layer, and there is no trouble of fusion with the dye thermal transfer sheet, and a manufacturing method for obtaining a high-quality thermal transfer receiving sheet. It is.

The dye thermal transfer method includes a dye thermal transfer sheet having a dye layer (hereinafter simply referred to as “ink ribbon”) and a thermal transfer receiving sheet having an image receiving layer for receiving the dye (hereinafter also simply referred to as “receptor sheet”). In this method, the dye layer and the image receiving layer are superposed and the dye is transferred onto the image receiving layer by heating to form an image. Heating is performed with a thermal head, and a full-color image is formed with multicolored dots. Since the dye is used, the image is clear and highly transparent, and a high-quality image usable for photographic use is obtained.

For the image receiving layer of the receiving sheet, a thermoplastic resin having a good dye dyeing property is used. The organic solvent or water can be used as the solvent for the receiving layer coating solution. However, recently, for reasons of environmental considerations, a water-dispersible or water-soluble resin is used as the coating solution for the image receiving layer. It is desired to have water as a main component.

The thermal transfer printing is a contact type printing method in which the dye of the ink ribbon is transferred to the image receiving layer by the heat supplied from the thermal head. It is considered that the thermoplastic resin that is the main component of the image receiving layer is softened by the heat from the thermal head to form a gap between molecules, and the dye is dyed in the gap. In general, the easier the image receiving layer is softened by the heat from the thermal head, the more easily the dye is dyed, and the print density can be increased.

However, if the heat resistance of the thermoplastic resin is insufficient, depending on the printing conditions, there is a problem that the ink ribbon and the image receiving layer are fused in the printer and the printing stops, so the thermoplastic resin is used in the image receiving layer. There is known a method of increasing the heat resistance of an image receiving layer using a crosslinking agent that undergoes a crosslinking reaction.

The crosslinking agent reacts with a functional group such as a hydroxyl group or a carboxyl group of the thermoplastic resin to form a crosslinked structure. After the image-receiving layer is applied in the production process, the image-receiving layer is wound in a state where the thermal transfer receiving sheet is wound up. Will contact with the back side of the thermal transfer receiving sheet, the cross-linking agent present on the surface of the image receiving layer also binds to the functional group of the back side of the thermal transfer receiving sheet or the back layer surface provided on the back side, thus causing blocking. easy.
When the image-receiving layer and the back surface attached by blocking are peeled off, a part of the image-receiving layer is peeled off, or a part of the back surface is attached to the image-receiving layer, which causes serious image defects when printing. .

In order to avoid blocking, a sublimation thermal transfer receiving sheet using a specific polyester resin as a dye dyeable resin for an image receiving layer is disclosed (Patent Document 1). However, if the dye dyeable resin is limited to a polyester resin having a specific structure, depending on the type of dye used in the dye thermal transfer sheet, problems such as a decrease in printing density and a decrease in storage stability may occur. It was difficult to cope with a wide variety of thermal transfer printers developed in the past.

Japanese Patent Application Laid-Open No. 2002-019306 (first page)

  According to the production method of the present invention, there can be obtained an excellent thermal transfer receiving sheet which is free from printing defects due to blocking generated in the manufacturing process of the thermal transfer receiving sheet and does not cause a fusing trouble with the dye thermal transfer sheet.

As a result of intensive studies to solve the above problems, the present inventor has arrived at the present invention configured on the basis of the following technical matters.

(1) In a method for producing a sheet-like support comprising cellulose pulp as a main component and a thermal transfer receiving sheet having an image receiving layer on one surface of the sheet-like support, a water-dispersible or water-soluble dyeing resin And an image-receiving layer coating solution containing a crosslinking agent, and drying with a dryer using hot air or near infrared rays to form an image-receiving layer. After the thermal transfer receiving sheet passes through the dryer, A method for producing a thermal transfer receiving sheet, comprising a step of bringing the surface of an image receiving layer into contact with a roll heated to 50 to 200 ° C. in a state where the layer surface temperature is maintained at 30 ° C. or higher.
(2) The thermal transfer receiving sheet according to (1), wherein the crosslinking agent used in the image receiving layer is a carbodiimide-based crosslinking agent.
(3) The thermal transfer according to (1) or (2), wherein the ratio of the crosslinking agent in the image-receiving layer coating solution is 0.5 to 30 parts by mass with respect to 100 parts by mass of the water-dispersible or water-soluble resin. Receptor sheet.
(4) The method for producing a thermal transfer receiving sheet according to any one of (1) to (3), wherein the smoothness of the surface of the image receiving sheet on which no image receiving layer is provided is 120 seconds or more and 4200 seconds or less.

  According to the present invention, a thermal transfer receiving sheet free from image defects due to blocking and having good printing runnability can be obtained.

The thermal transfer receiving sheet of the present invention has a structure in which an image receiving layer or the like is laminated on at least one surface of a sheet-like support, but it is of course possible to improve the performance by providing another layer. These layers will be described in detail below.
(Sheet support)
As the sheet-like support used for the thermal transfer receiving sheet of the present invention, papers mainly composed of cellulose pulp are used. Examples of paper include high-quality paper (acidic paper, neutral paper), medium-quality paper, coated paper, art paper, glassine paper, and resin-laminated paper.

(Image receiving layer)
As the resin for forming the image receiving layer, a resin having high affinity for the dye transferred from the ink ribbon and having good dye dyeing property (hereinafter referred to as dyeing resin) is used. Such dyeing resins include polyester resin, polycarbonate resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, polyvinyl acetal resin, polyvinyl butyral resin, polystyrene resin. Preferred are cellulose derivative resins such as polyacrylic ester resins and cellulose acetate butyrate, thermoplastic resins such as polyamide resins, and active energy ray curable resins.

The resin forming the image receiving layer of the present invention is water-dispersible or water-soluble. As a water-solubilizing method, there is a method of introducing a hydrophilic group such as a hydroxyl group, a carboxyl group or a sulfone group into the dyeable resin. When water-solubilization cannot be achieved by introduction of a hydrophilic group, or water-solubility cannot be achieved even by introduction of a hydrophilic group, water dispersibility can be achieved by an emulsion production method using an emulsifier.

(Crosslinking agent)
The crosslinking agent used in the image receiving layer of the present invention to form a crosslinking reaction product with the dyeable resin includes a carbodiimide crosslinking agent, an oxazoline crosslinking agent, an isocyanate crosslinking agent, an aziridine crosslinking agent, and a melamine crosslinking. Agents and the like. When a resin into which a carboxyl group has been introduced for hydrophilization is used for the receiving layer, the carbodiimide-based crosslinking agent and the oxazoline-based crosslinking agent are preferably fast in the crosslinking reaction rate with the carboxyl group, and the carbodiimide-based crosslinking agent is This is particularly preferable since a thermal transfer receiving sheet having high heat resistance of the cross-linked reaction product and good printer running property can be obtained.

Examples of commercially available crosslinking agents include carbodiimide-based crosslinking agents such as lupranate (manufactured by BASF), stabaxol (manufactured by Bayer), carbodilite (manufactured by Nisshinbo), and oxazoline-based crosslinking agents such as Epocross K-2040E (manufactured by Nippon Shokubai Co., Ltd.). And isocyanate crosslinking agents such as NK assist IS-70N (manufactured by Nikka Chemical Co., Ltd.).
The mass ratio of the water-soluble or water-dispersible resin and the crosslinking agent contained in the image receiving layer of the present invention is preferably 1 to 30 parts by mass of the crosslinking agent with respect to 100 parts by mass of the water-soluble or water-dispersible resin. If the crosslinking agent is less than 1 part by mass, the crosslinking reaction is insufficient, the heat resistance of the image receiving layer is insufficient, and the running property during printing may be inferior. If it exceeds 30 parts by mass, the unreacted cross-linking agent may impair the strength and heat resistance of the image receiving layer, resulting in poor print running properties.

(Release agent)
In order to prevent the ink ribbon from fusing to the image receiving layer during printing and to make the ink ribbon easily peel from the image receiving layer, the image receiving layer of the present invention may contain a release agent. preferable. Examples of the release agent used in the image receiving layer of the present invention include waxes and silicone compounds.

Examples of waxes include carnauba wax, paraffin wax, microcrystalline wax, polyethylene wax, candelilla wax, rice wax, montan wax, fatty acid amide wax, and fatty acid metal salt.

Examples of the silicone compound include silicone oil, silicone oil emulsion, and polysiloxane segment-containing polymer. Among these, a polysiloxane segment-containing aqueous resin is particularly preferable. Polysiloxane segment-containing water-based resin is a resin in which the polysiloxane segment is block copolymerized or graft copolymerized with other resins, and the resin copolymerized with the polysiloxane segment contributes to adhesion to adjacent layers and substrates. Therefore, sufficient interlayer strength as a thermal transfer receiving sheet can be obtained.

Furthermore, if necessary, one or more of fluorescent dyes, plasticizers, antioxidants, pigments, fillers, ultraviolet absorbers, light stabilizers, antistatic agents, and the like may be added to the image receiving layer. . These additives may be mixed with the component for forming the image receiving layer before coating, or may be coated on and / or below the image receiving layer as a coating layer separate from the image receiving layer. Also good.

The solid content coating amount of the receiving layer is in the range of 0.1 to 12 g / m ² , more preferably 1 to 10 g / m ² . Incidentally, when the solid content coating amount of the receiving layer is 0.1 g / m ² or more, it is possible to prevent the image receiving layer from becoming discontinuous and to prevent deterioration in image quality. On the other hand, by setting the solid content coating amount to 12 g / m ^{2 or} less, it is possible to maintain the coating strength of the image receiving layer and to prevent the image quality from being deteriorated by peeling off during printing.

(Heating roll treatment)
In the method for producing a thermal transfer receiving sheet of the present invention, an image receiving layer coating solution containing a water-dispersible or water-soluble resin and a crosslinking agent is applied on one surface of a sheet-like support, and hot air or near infrared rays are used. After drying with a dryer to form an image receiving layer, after the thermal transfer receiving sheet passes through the dryer, the surface of the image receiving layer is kept at 50 to 200 ° C. while maintaining the surface temperature of the image receiving layer at 30 ° C. or higher. A step of contacting with a heated roll.

  Contacting the surface of the image receiving layer with a heated roll causes the image receiving layer to be deformed by pressure, unlike drying using hot air or near infrared rays. By deforming the image receiving layer once dried and fixed, the reactive group of the unreacted cross-linking agent and the functional group of the resin can be contacted and reacted, and the cross-linking reaction of the image receiving layer can be promoted. While preventing blocking in the process, the effect of preventing fusion with the ink ribbon can be enhanced.

  When the image receiving layer is cooled and solidified, it becomes difficult for the reactive group of the unreacted crosslinking agent and the functional group of the resin to contact and react, and the molecular structure is fixed. After passing through a drier using near infrared rays, it is necessary to bring the surface of the image receiving layer into contact with a heated roll while maintaining the surface temperature of the image receiving layer at 30 ° C. or higher.

  The higher the holding temperature of the thermal transfer receiving sheet between the dryer and the heated roll, the higher the effect of promoting the crosslinking reaction, and it is more preferable that the holding temperature be 40 ° C. or higher. However, the holding temperature is preferably 80 ° C. or lower because if the holding temperature is too high, the receiving layer may stick to the heated roll and the receiving layer may be destroyed.

The heated roll brought into contact with the surface of the image receiving layer is preferably a roll having a metallic mirror surface since the surface shape of the roll after the contact is transferred to the surface of the image receiving layer.

It is preferable to apply a pressure when bringing the heated roll into contact with the surface of the image receiving layer because the image receiving layer can be further deformed and a crosslinking reaction of the image receiving layer can be promoted.

The pressure applied when the heated roll and the surface of the image receiving layer are brought into contact with each other is preferably adjusted to 5 to 20 kg / cm. By setting the pressure to 5 kg / cm or more, the crosslinking reaction of the image receiving layer can be further advanced. By controlling the pressure to 20 kg / cm or less, it is possible to suppress the crushing of the gaps in the sheet-like base material and the intermediate layer, and to easily maintain the heat insulating effect.

Moreover, it is preferable to adjust the applied pressure so that the smoothness (JIS) of the image receiving layer surface after contacting the heated roll and the image receiving layer surface is 2000 seconds or more. If necessary, a smoothing process can be performed in a later step to further improve the smoothness.

As a method for applying pressure when the heated roll and the surface of the image receiving layer are brought into contact with each other, a method of pressing another roll from the back side of the thermal transfer receiving sheet is preferable. The roll pressed from the back side of the thermal transfer receiving sheet is preferably a metal or resin roll. The surface of the resin roll is preferable because it is deformed by pressure and it is easy to apply uniform pressure to the thermal transfer receiving sheet.

(Back layer)
In the manufacturing method of this invention, a back surface layer can be provided in the back surface (surface on the opposite side to the side in which a receiving layer is provided) of a sheet-like support body. The back layer is used for the purpose of preventing curling of the thermal transfer receiving sheet, preventing sticking of the thermal transfer receiving sheet due to static electricity, and preventing blocking of the front and back surfaces of the thermal transfer receiving sheet.

Further, when the image receiving layer comes into contact with the back surface when the thermal transfer receiving sheet is wound up in a roll shape in the manufacturing process, the image receiving layer surface may copy the irregularities on the surface of the sheet-like support, and the image quality may deteriorate. In such a case, the unevenness on the surface of the sheet-like support can be filled with the back surface layer, and deterioration of image quality can be prevented.

Specifically, it is preferable that the smoothness (measurement method: conforming to JIS P 8119) of the outermost layer on the back surface of the thermal transfer receiving sheet is adjusted to 120 seconds or more without deterioration of image quality. Further, if the smoothness of the outermost layer on the back surface of the thermal transfer receiving sheet is adjusted to 4200 seconds or less, the frictional force with the paper feed roll in the printer becomes an appropriate value, and unevenness in the image due to unevenness in the conveying speed of the receiving sheet can be prevented. preferable.
The back layer can be formed of a resin, an inorganic pigment, an organic pigment, a conductive agent, a surfactant, or the like, if necessary, alone or in combination.

(Middle layer)
One or more intermediate layers may be provided between the sheet-like support and the image receiving layer. The intermediate layer is provided for the purpose of improving image quality by improving the coatability of the image receiving layer, improving the storage stability of the image, smoothing effect, heat insulating effect, and cushioning effect.

Since the present invention uses papers mainly composed of cellulose pulp as the sheet-like support, by providing an intermediate layer containing hollow particles, smoothness, heat insulation, cushioning properties are improved, and image quality and printing are improved. It is preferable to increase the concentration. As the hollow particles contained in the intermediate layer, expandable hollow particles obtained by encapsulating a vaporizable material in resin particles and heat-foamed are preferable because of their high heat insulation effect and cushion effect.

Example (Preparation of Receptive Layer Coating Substrate A-1)
As a sheet-like support, a high-quality paper having a thickness of 150 μm and a smoothness of 80 seconds is used, and the intermediate layer coating liquid B-1 having the following composition is applied to one side thereof, and the solid content coating amount is 18 g / m ² . Thus, coating and drying were performed to form an intermediate layer, and a receiving layer coating base material A-1 was produced.
Intermediate layer coating solution B-1
Pre-expanded hollow particles (average particle diameter 3.2 μm, volume hollowness 85%) made of a copolymer mainly composed of acrylonitrile and methacrylonitrile 35 parts polyvinyl alcohol (trade name: PVA205, manufactured by Kuraray) 10 parts polybutadiene resin (Product name: LX111, Tg = −80 ° C., manufactured by Nippon Zeon Co., Ltd.) 35 parts Water 200 parts

(Preparation of receiving layer coating base material A-2)
Coating the back surface layer coating liquid C-1 having the following composition on the surface of the receiving layer coating base material A-1 where the intermediate layer is not formed so that the solid content coating amount is 3 g / m ^2. Then, it was dried to form a back surface layer to prepare a receiving layer coating base material A-2. The smoothness of the back layer was 420 seconds.
Back layer coating liquid C-1
Acrylic resin (trade name: Rikabond FK-462S, manufactured by Chuo Rika Co., Ltd.) 70 parts polyvinyl alcohol (trade name: PVA105 manufactured by Kuraray Co., Ltd.) 30 parts Water 300 parts

(Preparation of receiving layer coating base material A-3)
Coating the back surface layer coating liquid C-2 having the following composition on the surface of the receiving layer coating base material A-1 where the intermediate layer is not formed, so that the solid content coating amount is 3 g / m ^2. Then, a back layer was formed by drying to prepare a receiving layer coating base material A-3. The smoothness of the back layer was 130 seconds.
Back layer coating liquid C-2
Aluminum hydroxide pigment (trade name: Heidilite H-42, manufactured by Showa Denko KK) 70 parts polyvinyl alcohol (trade name: PVA105 made by Kuraray) 30 parts Water 300 parts

(Formation of image receiving layer)
(Coating dryer for image receiving layer)
Examples 1-14 and Comparative Examples below using a coating drier having a gravure coater, a subsequent hot air dryer, a calender having a heating roll following the hot air dryer, and a winding device following the calendar 1-3 were implemented.
The image receiving layer surface temperature measured at the observation point immediately after the hot air dryer is E-1, the image receiving layer surface temperature measured at the observation point immediately before contacting the heating roll of the calendar is E-2, the heating roll. The surface temperature of was set to E-3. The receiving layer surface temperature was measured using a radiant thermometer IT-540N manufactured by Techjam, and the surface temperature of the heating roll was measured using a contact thermometer HA-100E manufactured by Anritsu Keiki Co., Ltd.

Example 1
On the intermediate layer of the receiving layer coating substrate A-2, an image receiving layer coating solution D-1 having the following composition is applied to the image receiving layer so that the solid content coating amount is 2 g / m ² . The coating was dried using a coating drier to obtain a thermal transfer receiving sheet. The temperature conditions at this time were E-1: 45 ° C, E-2: 43 ° C, and E-3: 100 ° C. Further, the linear pressure at the nip portion of the calendar was adjusted to 10 kg / cm, and the smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 5500 seconds.

Image receiving layer coating solution D-1
Water-soluble urethane resin (trade name: Neo sticker # 1700, manufactured by Nikka Chemical Co., Ltd.) 100 parts Carbodiimide crosslinking agent (trade name: E-04, manufactured by Nisshinbo) 1.5 parts Water 300 parts

Example 2
On the intermediate layer of the receiving layer coating substrate A-2, an image receiving layer coating liquid D-2 having the following composition is applied to the image receiving layer so that the solid content coating amount is 2 g / m ² . The coating was dried using a coating drier to obtain a thermal transfer receiving sheet. The temperature conditions at this time were E-1: 45 ° C, E-2: 43 ° C, and E-3: 100 ° C. The pressure at the nip portion of the calendar was adjusted to 10 kg / cm, and the smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 5300 seconds.

Image receiving layer coating solution D-1
100 parts of vinyl chloride vinyl acetate copolymer resin emulsion (trade name: VINYBRAN 603, manufactured by Nissin Chemical)
Carbodiimide crosslinking agent (trade name: E-04, manufactured by Nisshinbo) 1.5 parts water 300 parts

Example 3
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the receiving layer coating substrate A-1 was used instead of the receiving layer coating substrate A-2 in Example 1. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 4900 seconds.

Example 4
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the receiving layer coating substrate A-3 was used in place of the receiving layer coating substrate A-2. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 5200 seconds.

Example 5
A thermal transfer receiving sheet was obtained in the same manner as in Example 1, except that the temperature conditions were changed to E-1: 33 ° C, E-2: 32 ° C, and E-3: 100 ° C. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 4300 seconds.

Example 6
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the temperature conditions were changed to E-1: 45 ° C, E-2: 43 ° C, and E-3: 190 ° C in Example 1. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 6000 seconds.

Example 7
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the temperature conditions were changed to E-1: 72 ° C, E-2: 69 ° C, and E-3: 100 ° C in Example 1. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 6300 seconds.

Example 8
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the temperature conditions were changed to E-1: 85 ° C, E-2: 82 ° C, and E-3: 100 ° C in Example 1. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 3500 seconds.

Example 9
In Example 1, a thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the pressure at the nip portion of the calendar was changed to 5 kg / cm. The smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 4000 seconds.

Example 10
In Example 1, a thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the pressure at the nip portion of the calendar was changed to 20 kg / cm. The smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 6200 seconds.

Example 11
In Example 1, a thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the pressure at the nip part of the calendar was changed to 3 kg / cm. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 2300 seconds.

Example 12
In Example 1, a thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the pressure at the nip portion of the calendar was changed to 23 kg / cm. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 6300 seconds.

Example 13
On the intermediate layer of the receiving layer coating substrate A-2, an image receiving layer coating solution D-3 having the following composition is applied to the image receiving layer so that the solid content coating amount is 2 g / m ² . The coating was dried using a coating drier to obtain a thermal transfer receiving sheet. The temperature conditions at this time were E-1: 45 ° C, E-2: 43 ° C, and E-3: 100 ° C. The pressure at the nip portion of the calendar was adjusted to 10 kg / cm, and the smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 4800 seconds.

Image receiving layer coating solution D-3
Water-soluble urethane resin (trade name: Neo Sticker # 1700, manufactured by Nikka Chemical) 100 parts Isocyanate crosslinking agent (trade name: IS-100N, manufactured by Nikka Chemical Co., Ltd.) 1.5 parts Water 300 parts

Example 14
On the intermediate layer of the receiving layer coating substrate A-2, an image receiving layer coating solution D-4 having the following composition is applied to the image receiving layer so that the solid content coating amount is 2 g / m ² . The coating was dried using a coating drier to obtain a thermal transfer receiving sheet. The temperature conditions at this time were E-1: 45 ° C, E-2: 43 ° C, and E-3: 100 ° C. Further, the pressure at the nip portion of the calendar was adjusted to 10 kg / cm, and the smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 5600 seconds.

Image receiving layer coating solution D-4
Water-soluble urethane-based resin (trade name: Neo Sticker # 1700, manufactured by Nishua Chemical Co., Ltd.) 100 parts Carbodiimide crosslinking agent (trade name: E-04, manufactured by Nisshinbo Co., Ltd.) 0.5 part Water 300 parts

Example 15
On the intermediate layer of the receiving layer coating substrate A-2, an image receiving layer coating solution D-5 having the following composition is applied to the image receiving layer so that the solid content coating amount is 2 g / m ² . The coating was dried using a coating drier to obtain a thermal transfer receiving sheet. The temperature conditions at this time were E-1: 45 ° C, E-2: 43 ° C, and E-3: 100 ° C. The pressure at the nip portion of the calendar was adjusted to 10 kg / cm, and the smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 5300 seconds.

Image receiving layer coating solution D-5
Water-soluble urethane-based resin (trade name: Neo sticker # 1700, manufactured by Nishua Chemical) 100 parts Carbodiimide crosslinking agent (trade name: E-04, manufactured by Nisshinbo) 28 parts Water 300 parts

Example 16
On the intermediate layer of the receiving layer coating substrate A-2, an image receiving layer coating solution D-5 having the following composition is applied to the image receiving layer so that the solid content coating amount is 2 g / m ² . The coating was dried using a coating drier to obtain a thermal transfer receiving sheet. The temperature conditions at this time were E-1: 45 ° C, E-2: 43 ° C, and E-3: 100 ° C. Further, the pressure at the nip portion of the calendar was adjusted to 10 kg / cm, and the smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 5000 seconds.

Image receiving layer coating solution D-5
Water-soluble urethane-based resin (trade name: Neo sticker # 1700, manufactured by Nikka Chemical) 100 parts Carbodiimide crosslinking agent (trade name: E-04, manufactured by Nisshinbo) 33 parts 300 parts of water

Comparative Example 1
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the temperature conditions were changed to E-1: 28 ° C, E-2: 27 ° C, and E-3: 100 ° C in Example 1. The smoothness of the receiving layer surface of the obtained thermal transfer receiving sheet was 1500 seconds.

Comparative Example 2
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the temperature conditions were changed to E-1: 45 ° C, E-2: 44 ° C, and E-3: 46 ° C in Example 1. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 800 seconds.

Comparative Example 3
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the temperature conditions were changed to E-1: 45 ° C, E-2: 43 ° C, and E-3: 210 ° C in Example 1. The smoothness of the surface of the receiving layer of the obtained thermal transfer receiving sheet was 1800 seconds.

Evaluation The following tests were conducted on the receiving sheets obtained in the above Examples and Comparative Examples. The obtained results are shown in Table 1.

"blocking"
The state of the receiving sheet roll wound up by the winding device of the image receiving layer coating dryer was evaluated according to the following evaluation criteria.
A: Very good with no adhesion of the front and back surfaces of the receiving sheet.
○: Peeling sound is generated when the front and back surfaces of the receiving sheet are separated, but no abnormality is seen on the front and back surfaces of the receiving sheet.
Δ: Peeling sound is made when the front and back surfaces of the receiving sheet are separated, and a sticking mark is seen on the front and back surfaces of the receiving sheet, but there is no practical problem.
X: There is resistance when separating the front and back surfaces of the receiving sheet, and damage is observed on a part of the front and back surfaces of the receiving sheet, which is not practical.

"Runability"
In a 40 ° C environment, using a commercially available thermal transfer video printer (trade name: DPP-SV55, manufactured by Sony Corporation) and a dedicated dye thermal transfer sheet cartridge, the receiving sheet cut to a predetermined size is set on the paper feed tray and black. 20 solid images were printed continuously. The state at the time of printing and the printed matter were evaluated based on the following evaluation criteria.
(Double-circle): The peeling sound of a dye thermal transfer sheet is small, and there is no defect in the printed material, which is very good.
○: The peeling sound of the dye thermal transfer sheet is large, but there is no defect in the printed material, which is good.
Δ: Peeling sound of the dye thermal transfer sheet is large and peeling marks are seen in the printed matter, but there is no practical problem. X: Ribbon fusion occurred before 20 sheets of printing were finished, and was not practical.

"Print density"
In a 23 ° C. environment, using a commercially available thermal transfer video printer (trade name: DPP-SV55, manufactured by Sony Corporation) and a dedicated dye thermal transfer sheet cartridge, set the receiving sheet cut to a predetermined size on the paper feed tray, A tone pattern image was printed. The printed matter was evaluated based on the following evaluation criteria.
A: Good image quality is obtained at all gradations, and the image quality is extremely high.
○: White spots are seen only in the low gradation part, but the image quality is high.
(Triangle | delta): It is the image quality in which a white spot is seen in some places, but there is no problem practically.
X: Many white spots are seen and not practical.

  As apparent from Table 1, the method for producing a thermal transfer receiving sheet of the present invention is an excellent method for producing no blocking. Further, the thermal transfer receiving sheet obtained by the production method of the present invention is a thermal transfer receiving sheet having high image quality and excellent print running properties.

  According to the present invention, it is possible to provide a thermal transfer receiving sheet with high image quality and excellent print running property, which is extremely useful in practice.

Claims (4)

  A sheet-like support comprising cellulose pulp as a main component, and a method for producing a thermal transfer receiving sheet having an image-receiving layer on one surface of the sheet-like support, and a water-dispersible or water-soluble dyeing resin and a crosslinking agent The image-receiving layer coating solution is applied, dried with a dryer using hot air or near infrared rays to form an image-receiving layer, and after the thermal transfer receiving sheet passes through the dryer, the image-receiving layer surface temperature Having a step of contacting the surface of the image receiving layer with a roll heated to 50 to 200 ° C. while maintaining 30 ° C. or higher.   The thermal transfer receiving sheet according to claim 1, wherein the crosslinking agent used in the image receiving layer is a carbodiimide-based crosslinking agent. The thermal transfer receiving sheet according to claim 1 or 2, wherein a ratio of the crosslinking agent in the image receiving layer coating liquid is 0.5 to 30 parts by mass with respect to 100 parts by mass of the water-dispersible or water-soluble resin.   The method for producing a thermal transfer receiving sheet according to claim 1, wherein the smoothness of the surface of the image receiving sheet on which no image receiving layer is provided is 120 seconds or more and 4200 seconds or less.