JP2588472B2 - Method of manufacturing heat transfer 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 method for producing a heat-transferable sheet which is used in combination with a thermal transfer sheet and has a receiving layer for forming an image with a dye transferred from the thermal transfer sheet.

[0002]

2. Description of the Related Art A thermal transfer sheet having a dye layer containing a sublimable disperse dye is heated by a thermal head or the like in a dot-like manner in accordance with an image signal, and the dye is transferred to the surface of the sheet to be transferred. Attempts have been made to form images with the dyes used.

[0003] Such a heat transfer sheet has a structure in which a receptor layer for receiving a dye migrating from the transfer sheet is provided on the surface of a sheet-like substrate, and has a feature that a clear printed image can be obtained. ing.

In general, in producing a heat transfer sheet, a composition for forming a receiving layer is coated on a sheet-like substrate and dried to form a receiving layer. Conventionally, a drying step is performed under specific conditions. The method of drying has not been adopted.

[0005] That is, conventionally, drying of a coated product is limited to a general drying range in which a solvent is simply removed, and drying from a management aspect of the solvent content is performed by paying attention to the solvent content. I wasn't.

[0006]

In forming the receiving layer, the solvent content in the receiving layer also depends on the degree of drying.

In the production of a sheet to be heat-transferred, forming a receptor layer on a sheet-like substrate requires a large amount of coating compared with general printing due to its function. Also increases. Therefore, a certain amount of solvent remains in the receiving layer if the drying is carried out in the drying step, and a heat transfer sheet having a receiving layer having a relatively large amount of the remaining solvent is produced. Invite.

For example, even after the composition for forming a receptor layer is applied and dried by a dryer provided in a printing machine or a coater, about 5 to 6% of the solvent remains in the receptor layer.

In such a heat transfer sheet, when printing is performed together with the heat transfer sheet, a clear image can be obtained at the time of printing, but diffusion occurs due to the solvent remaining during storage, and as a result, the image is blurred. There was a problem of getting it.

If the amount of the residual solvent is large, the odor of the solvent remains, and this odor is particularly undesirable when the printed sheet is used for food packaging.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a method for producing a heat-transferable sheet which is free from the problem of image blurring over time after printing and free from odor due to residual solvent. And

[0012]

In order to solve the above-mentioned problems, the present invention relates to a method for drying a coated receiving layer forming composition, wherein the weight of the solvent in the receiving layer is reduced by the weight of the receiving layer forming resin. Drying is carried out under a specific condition of removing the solvent so as to be 1% or less.

That is, the method for producing a heat transfer sheet of the present invention is directed to a method for producing a heat transfer sheet used in combination with a heat transfer sheet having a dye layer containing a dye which is transferred by melting or sublimation by heat. A receiving layer-forming resin is dissolved or dispersed in a solvent, and the receiving layer-forming composition is applied to the substrate, and dried to form a receiving layer. In the drying step, the solvent in the receiving layer is dried. The method is characterized in that the solvent is removed so that the weight is 1% or less of the weight of the receiving layer forming resin.

In the present invention, the composition for forming a receiving layer is coated on a sheet-like substrate. The composition for forming a receiving layer is obtained by dissolving or dispersing a resin for forming a receiving layer in a solvent. Things.

In the present invention, the receiving layer forming resin is a resin capable of receiving an image of a dye migrating from a thermal transfer sheet, for example, a sublimable disperse dye, and capable of maintaining an image formed by the reception. As long as it is used for the receiving layer of this type of heat transfer sheet, any material can be used.
The synthetic resin (e) can be used alone or in combination of two or more.

(A) Those having an ester bond. Polyester resin, polyacrylate resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, vinyl toluene acrylate resin. (B) Those having a urethane bond. Polyurethane resin and the like. (C) Those having an amide bond. Polyamide resin (nylon). (D) Those having a urea bond. Urea resin and the like. (E) Others having a highly polar bond. Polycaprolactone resin, polystyrene resin, polyvinyl chloride resin, polyacrylonitrile resin, etc.

Alternatively, the receiving layer is composed of a mixed resin of a saturated polyester and a vinyl chloride / vinyl acetate copolymer.

The vinyl chloride / vinyl acetate copolymer resin has a vinyl chloride component content of 85 to 97% by weight and a degree of polymerization of 200.
Those of about 800 are preferable. Further, the copolymer may be a copolymer containing only a vinyl chloride / vinyl acetate copolymer component, but may contain a vinyl alcohol component, a maleic acid component and the like.

The receiving layer may be composed of a polystyrene resin, for example, a styrene monomer, for example, a polystyrene resin composed of a homopolymer or a copolymer of styrene, α-methylstyrene and vinyltoluene, or The styrene-based monomer and other monomers, for example, styrene-based copolymer resin which is a copolymer of acrylic or methacrylic-based monomer such as acrylate, methacrylate, acrylonitrile, methacrylonitrile or maleic anhydride. No.

As the solvent used for preparing the composition for forming the receptor layer by dissolving or dispersing the resin for forming the receptor layer, a conventional solvent can be used, for example, isopropyl alcohol, methyl alcohol, ethyl alcohol, n-butyl alcohol. Alcohol solvents such as methyl ethyl ketone and methyl isobutyl ketone; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and butyl acetate; n-hexane and cyclohexanone.

In the present invention, the composition for forming a receptor layer as described above is coated on a sheet-like substrate. The term “coating” as used herein means that a layer of the composition is formed on the substrate by a coating method. A method of forming the composition layer by printing, and a method of forming the composition layer on a temporary carrier different from the sheet-like substrate once, and then re-forming the composition layer on the sheet-like substrate. This is a concept that includes a method of transcription.

The sheet-like substrate used in the present invention includes synthetic paper (polyolefin, polystyrene, etc.), woodfree paper, art paper, coated paper, cast-coated paper, wallpaper backing paper, synthetic resin or emulsion impregnated paper, Films or sheets of various types of plastics such as synthetic rubber latex-impregnated paper, synthetic resin-containing paper, paperboard, or natural fiber paper such as cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, methacrylate, and polycarbonate can be used. Among them, synthetic paper is preferable because it has a microvoid layer having low thermal conductivity (in other words, high heat insulation) on its surface. Further, a laminate formed by any combination of the above-mentioned to (1) can also be used.

Examples of typical laminates include a laminate of cellulosic fiber paper and synthetic paper, or a laminate of cellulose fiber paper and a plastic film or sheet. Of these, the laminate of cellulose fiber paper and synthetic paper is
Cellulose fiber paper may compensate for the thermal instability (e.g., expansion and contraction) of the synthetic paper, and exhibit high printing thermal sensitivity due to the low thermal conductivity of the synthetic paper. In order to balance the front and back of the laminate in this combination, a three-layer laminate of synthetic paper, cellulose fiber paper, and synthetic paper is preferably used, and curling due to printing can be reduced.

As the synthetic paper used for the laminate as described above, any synthetic paper can be used as long as it can be used as a base material of the sheet to be thermally transferred. In particular, a paper-like layer having fine pores is provided. Synthetic paper (for example, commercially available synthetic paper: YUPO: Oji Yuka synthetic paper) is desirable. The fine holes in the paper-like layer can be formed, for example, by stretching a synthetic resin in a state containing a fine filler.
The heat transfer sheet formed using the synthetic paper provided with the paper-like layer containing the fine voids has an effect that, when an image is formed by thermal transfer, the image density is high and the image does not become rough.

This has a heat insulating effect due to the fine pores,
The good thermal energy efficiency and the good cushioning property due to the fine pores are considered to contribute to the receiving layer provided on the synthetic paper and on which an image is formed. Further, the paper-like layer having the fine pores can be provided directly on the surface of a core material such as cellulose fiber paper.

In addition to the cellulose fiber paper in the laminate, a plastic film may be used.
What laminated | stacked the said cellulose fiber paper and a plastic film can also be used.

Examples of the method of attaching the synthetic paper and the cellulose fiber paper include attaching using a conventionally known adhesive, attaching using an extrusion laminating method, and attaching using thermal bonding. Examples of a method for attaching the synthetic paper and the plastic film include a lamination method and a calendar method which simultaneously form the plastic film. The sticking means is appropriately selected according to the material of the material to be stuck to the synthetic paper. Specific examples of the adhesive include an ethylene-vinyl acetate copolymer, an emulsion adhesive such as polyvinyl acetate, a water-soluble adhesive such as a polyester containing a carboxyl group, and the like. And an adhesive of an organic solvent solution type such as polyurethane, acrylic or the like. The thickness of these substrates is usually preferably from 30 to 200 μm.

In the present invention, various additives can be contained in the composition for forming a receptor layer. For example, in the composition for forming a receiving layer for the purpose of improving the whiteness of the receiving layer to further enhance the clarity of the transferred image and imparting writability to the surface of the heat-receiving sheet, and preventing retransfer of the transferred image. Can be added with a white pigment. By adding a white pigment, an image can be transferred with higher definition and excellent heat resistance and moisture resistance. In addition, a resin-specific color (yellowish) due to lamination of a resin such as a receiving layer and a cushion layer described later.
Thus, it is possible to prevent the whiteness and glossiness of the base material from being impaired. In particular, when the base material is a natural paper such as cast-coated paper, the whiteness and glossiness and the smoothness are inferior to those of synthetic paper, so that the effect is large.

As the white pigment, titanium oxide, zinc oxide, kaolin clay and the like are used, and these can be used in combination of two or more. The addition amount of the white pigment is preferably 5 to 50 parts by weight based on 100 parts by weight of the resin constituting the receiving layer.

In the present invention, an ultraviolet absorber may be added to the composition for forming a receptor layer. By adding an ultraviolet absorber, the light fastness of the dyed dye is further improved. Benzophenone-based UV absorbers
Hindered amines, benzotriazoles and the like can be mentioned. The addition amount is about 0.05 to 5 parts by weight based on 100 parts by weight of the resin constituting the receiving layer.

In the present invention, a releasing agent can be contained in the composition for forming a receptor layer in order to improve the releasability from the thermal transfer sheet. Examples of the release agent include solid waxes such as polyethylene wax, amide wax, and Teflon powder, fluorine-based and phosphate-based surfactants, and silicone oil, but silicone oil is preferred.

As the silicone oil, an oily one can be used, but a hardening type is preferred. Examples of the curable silicone oil include a reaction curable type, a photocurable type, and a catalyst curable type, and a reaction curable type silicone oil is particularly preferable. The reaction-curable silicone oil is preferably one obtained by reacting and curing an amino-modified silicone oil and an epoxy-modified silicone oil. The addition amount of these curable silicone oils is preferably 0.5 to 30 parts by weight based on 100 parts by weight of the resin constituting the receiving layer.

After the above-mentioned releasing agent is dissolved or dispersed in an appropriate solvent and applied to part or all of the surface of the receptor layer,
The release agent layer can be provided by drying or the like.
As the release agent constituting the release agent layer, the above-mentioned cured product of the amino-modified silicone oil and the epoxy-modified silicone oil is particularly preferable. The thickness of the release agent layer is 0.01
To 5 μm, particularly preferably 0.05 to 2 μm. The release agent layer may be provided on a part of the surface of the receiving layer, or may be provided on the entire surface, but when provided on a part of the surface of the receiving layer, the dot impact on the part where the release agent layer is not provided is provided. Recording, heat-sensitive melting transfer recording and recording with a pencil etc. can be performed, sublimation transfer recording is performed on the part where the release agent layer is provided, and recording by other recording method is performed on the part where the release agent layer is not provided , Etc., can be performed in combination with the sublimation transfer recording method and another recording method.

In the present invention, the composition for forming a receiving layer is coated on a sheet-like substrate, and the resulting composition is sent to a drying step to form a receiving layer. In this drying step, the weight of the solvent in the receiving layer is reduced. The solvent is removed so as to be 1% or less of the weight of the forming resin.

As a drying method, industrially, the first stage of drying is carried out by a dryer attached to a usual printing machine, coater or the like, and dried until the solvent weight in the receiving layer becomes about 5 to 10%. Then, the second stage of drying is performed to reduce the solvent weight by 1%.
Do the following.

As the first stage drying method, for example, 120
It can be performed by passing at a predetermined speed through a drying hood of a predetermined length set to a temperature of ° C.

As the drying method in the second stage, for example, 60
It can be carried out by leaving it in an atmosphere of 100 ° C. for 10 days or more, or in an atmosphere of 100 ° C. for 10 minutes or more, or in an atmosphere of 120 ° C. for 2 minutes or more.

As a method for measuring the weight of the solvent in the receiving layer, the weight of the solvent and the weight of the solvent-soluble component in the resin composition at the time of forming the receiving layer and the weight of the solvent and the weight of the solvent-soluble component after drying are determined. You should measure it.

The basic structure of the heat transfer sheet manufactured by the method of the present invention is as shown in FIG. As shown in FIG. 1, the heat transfer sheet 1 is obtained by forming a receiving layer 3 on the surface of a sheet-like substrate 2.

In manufacturing a heat transfer sheet according to the method of the present invention, as shown in FIG.
It is also possible to provide an intermediate layer 4 between them, and by providing the intermediate layer 4, the heat insulating property and cushioning property of the surface during image formation can be improved. The intermediate layer 4 is either a cushioning layer or a porous layer depending on the constituent material, or may also serve as an adhesive in some cases.

The cushioning layer is mainly composed of a resin having a 100% modulus specified in JIS-K-6301 of 100 kg / cm ² or less.
If the% modulus exceeds 100 kg / cm ² , the rigidity is too high, so that even if an intermediate layer is formed using such a resin, sufficient adhesion between the thermal transfer sheet and the layer to be thermally transferred cannot be maintained. . The lower limit of the 100% modulus is practically about 0.5 kg / cm ² .

The following resins can be used as the resin meeting the above conditions.

Polyurethane resin, polyester resin, polybutadiene resin, polyacrylate resin, epoxy resin, polyamide resin, rosin-modified phenol resin, terpene phenol resin, ethylene / vinyl acetate copolymer resin.

The above-mentioned resins can be used alone or in combination of two or more. However, since the above-mentioned resins have relatively high tackiness, if there is any trouble during processing, it is possible to use inorganic materials. Additives, for example, silica, alumina, clay, calcium carbonate and the like, or amide-based substances such as stearamide may be added.

The cushioning layer is prepared by kneading the above-mentioned resin together with other additives as necessary with a solvent, a diluent or the like to form a paint or ink, and drying it as a coating film by a known coating method or printing method. Can be formed by
Its thickness is 0.5 to 50 μm, more preferably 2 to 20 μm.
It is about μm. When the thickness is 0.5 μm, the surface roughness of the provided sheet-like base material cannot be completely absorbed, and thus has no effect.
On the other hand, if it exceeds 50 μm, not only the effect is not improved, but also the receiving layer portion becomes too thick and protrudes, hindering winding and overlapping, and is not economical.

It is considered that the formation of such an intermediate layer improves the adhesion between the thermal transfer sheet and the heat transfer sheet because the intermediate layer itself is low in rigidity and is deformed by pressure during printing. Further, the resin as described above usually has a low glass transition point or softening point, and due to the thermal energy given at the time of printing, it also contributes to the fact that the rigidity is further reduced than at room temperature and is easy to deform. Presumed.

The porous layer is formed by applying a liquid in which a synthetic resin emulsion such as polyurethane or a synthetic rubber latex such as methyl methacrylate-butadiene or the like is bubbled by mechanical stirring on a substrate, and then drying the layer. A liquid obtained by mixing a foaming agent with the above synthetic rubber latex was applied on a substrate, and a dried layer, a synthetic resin such as vinyl chloride plastisol, polyurethane, or a synthetic rubber such as styrene-butadiene was mixed with a foaming agent. A layer formed by applying a liquid on a substrate and heating to heat, and a solution in which a thermoplastic resin or a synthetic rubber is dissolved in an organic solvent, and is less likely to evaporate than the organic solvent and has compatibility with the organic solvent. And a non-solvent (including water-based ones) having no solubility in a thermoplastic resin or a synthetic rubber,
A microporous layer formed by coating a substrate and drying to form a micro-aggregated film is used. In the above layers (1) to (4), the size of the bubbles is large. Therefore, when a solution for forming a receptor layer is applied on the layer and dried, the surface of the receptor layer formed by drying may have irregularities. Therefore, in order to obtain the surface of the receiving layer capable of transferring an image with small irregularities and high uniformity, it is preferable to provide the microporous layer as a porous layer.

Examples of the thermoplastic resin used for forming the microporous layer include saturated polyester, polyurethane, vinyl chloride / vinyl acetate copolymer, cellulose acetate propionate, and the like. Examples thereof include styrene-butadiene-based, isoprene-based, and urethane-based. Various organic solvents and non-solvents can be used as the organic solvent and non-solvent used in the formation of the microporous layer, but hydrophilic solvents such as methyl ethyl ketone and alcohol are usually used as the organic solvent, and water is used as the non-solvent. Used.

The thickness of the porous layer in the present invention is preferably 3 μm or more, particularly preferably 5 to 20 μm. When the thickness of the porous layer is less than 3 μm, the cushioning and heat insulating effects are not exhibited.

In the present invention, a lubricating layer may be provided on the back surface of the sheet-like substrate. In some cases, the heat transfer sheets are stacked and fed one by one to perform the transfer. In this case, if a slip layer is provided, the slip between the sheets becomes smooth, and the sheets can be fed accurately one by one. Examples of the material of the lubricating layer include a methacrylate resin such as methyl methacrylate or a corresponding acrylate resin, and a vinyl resin such as a vinyl chloride-vinyl acetate copolymer.

The heat transfer sheet manufactured according to the present invention may contain an antistatic agent. By including an antistatic agent, the sheets can be more smoothly slid and the effect of preventing dust from adhering to the heat transfer sheet can be obtained. The antistatic agent may be contained in the sheet-like base material, the receiving layer or the lubricating layer, or may be provided as an antistatic agent layer on the back surface of the sheet-like base material. It is preferable to provide it as an agent layer.

In the present invention, when a heat transfer sheet is manufactured, it is possible to provide a detection mark on the heat transfer sheet.
The detection mark is extremely convenient when positioning the heat transfer sheet and the heat transfer sheet, for example. For example, a detection mark that can be detected by the photoelectric tube detection device can be provided on the back surface of the sheet-like substrate by printing or the like.

When an intermediate layer or the like is provided in the heat transfer sheet manufactured according to the present invention, the amount of the solvent contained therein becomes a problem. There is no problem because it depends only on However, in terms of odor, although a problem arises when a large amount of solvent is contained in the intermediate layer and the like, the heat transfer sheet including the intermediate layer and the like is dried under the drying conditions according to the method of the present invention as described above. For example, since the amount of the solvent contained in the intermediate layer and the like becomes extremely small as in the case of the receiving layer, the problem of odor is also solved.

As described above, the heat transfer sheet produced by the method of the present invention is superimposed on the heat transfer sheet so that the color material layer of the heat transfer sheet and the receptor layer of the heat transfer sheet are in contact with each other. After heating by the like, the sublimable dye in the color material layer is transferred to the receiving layer of the heat transfer sheet by peeling the transfer sheet,
An image corresponding to the image information is recorded on the heat transfer sheet.

The heat transfer sheet manufactured by the method of the present invention includes 1) formation of a face photograph of a simple ID card, 2) formation of a face photograph of a business card, 3) painting on a telephone card, 4).
Premium, 5) postcard, 6) window advertisement, 7) illuminated signboard,
8) Various decorations, 9) Tag, 10) Product description label, 1
Applicable to 1) stationery labels, 12) indexes for audio cassettes and video cassettes, etc.

[0056]

The present invention will be described below in more detail with reference to examples and comparative examples. Examples 1 and 2, Comparative Examples 1 and 2 As a support, a 9 μm-thick P having a corona treatment on one surface was used.
An ink composition for a thermal transfer layer having the following composition was applied to an ET film (manufactured by Toyobo: S-PET) by wire bar coating so that the coating weight when dried was 1.0 g / m ² , dried, and silicone was applied to the back surface. After dropping a drop of oil (Shin-Etsu Silicone: X-44003A) with a dropper, spread it over the entire surface and subject it to backside treatment to obtain a thermal transfer sheet.

4 parts by weight of disperse dye for ink composition for thermal transfer layer (manufactured by Nippon Kayaku: Kayaset Blue 714) 4.3 parts by weight of polyvinyl butyral (manufactured by Sekisui Chemical: S-LEC BX-1) 40 parts by weight of toluene 40 parts by weight of methyl ethyl ketone 10 parts by weight of isobutanol

Here, polyvinyl butyral (BX-1)
Has a molecular weight of about 100,000, a Tg of 83 ° C., and a weight percent of vinyl alcohol part of about 20%. The resulting thermal transfer layer was transparent, and no particles were observed under a microscope (400-fold magnification).

Next, a synthetic paper having a thickness of 150 μm (YUPO-FPG150, manufactured by Oji Oil Chemical Co., Ltd.) was used as a base material, and the ink composition for a receiving layer having the following composition was roll-coated to a thickness of 9. The same coating sheet was prepared by coating at 3 g / m ² to prepare four types of the same coating sheet. The first-stage drying was performed by passing the coated sheet through a drying hood having a length of 120 m and a length of 20 m at a speed of 50 m / min. Thus, a heat transfer sheet having the receiving layer formed thereon was obtained. After the second stage, the weight of the solvent was 8.2% based on the weight of the resin for forming the receiving layer in the receiving layer of each heat transfer sheet. Next, Table 1
The second-stage drying of each heat-transferred sheet was performed under the second-stage drying conditions shown in FIG. The weight of the solvent with respect to the weight of the resin for forming the receiving layer in the receiving layer of each sheet after the second-stage drying is shown in Table 1.

8 parts by weight of ink composition Byron 103 for receiving layer (Polyester resin: manufactured by Toyobo) 2 parts by weight of Elvaloy 741 (EVA-based polymer plasticizer: manufactured by Mitsui Polychemicals) 0.125 part by weight of amino-modified silicone (KF-393: Shin-Etsu Silicone) Epoxy-modified silicone 0.125 parts by weight (X-22-343: Shin-Etsu Silicone) Toluene 70 parts by weight Methyl ethyl ketone 10 parts by weight Cyclohexanone 20 parts by weight

The thermal transfer sheet obtained as described above,
Each heat transfer sheet is overlapped so that the heat transfer layer and the receiving layer are in contact with each other, and the output of the thermal head is 1 W / 1 dot, pulse width: 0.3 to 4.5 msec, dot density: 3 dots /
As a result of recording under the condition of mm, the print density shown in Table 1 was obtained.

Further, among the heat transfer sheets after printing, those of Examples 1 and 2 did not feel odor, while Comparative Examples 1 and 2
It felt the odor peculiar to the solvent. Table 1 also shows the results of examining the storage stability of each heat transfer sheet.

[0063]

[Table 1]

[0064]

According to the present invention, the composition for forming a receptor layer is coated on a sheet-like substrate and dried to form a receptor layer to form the receptor layer. Since the solvent is removed such that the weight of the solvent is 1% or less of the weight of the resin for forming the receiving layer, it is possible to produce a heat transfer sheet having an extremely small amount of residual solvent in the receiving layer.

Since the heat transfer sheet produced by the method of the present invention has a very small amount of residual solvent in the receiving layer,
There is no danger of image blurring over time after printing, and an extremely clear image can be maintained for a long time.

Further, since the sheet has no problem of generation of odor due to the residual solvent, there is no problem even if the sheet on which an image is formed by printing is used for food packaging.
It exerts a remarkable effect in the application.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a heat transfer sheet manufactured by the method of the present invention.

FIG. 2 is a longitudinal sectional view of another configuration example of a heat transfer sheet manufactured by the method of the present invention.

[Description of Signs] 1 Thermal transfer sheet 2 Sheet-shaped base material 3 Reception layer 4 Intermediate layer

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-135791 (JP, A) JP-A-61-11293 (JP, A) JP-A-61-27290 (JP, A) JP-A-61-27290 144394 (JP, A)

Claims (1)

(57) [Claims] In a method for producing a heat transfer sheet used in combination with a heat transfer sheet having a dye layer containing a dye which is transferred by melting or sublimation by heat, a receiving layer forming resin is formed on a sheet-like substrate. A composition for forming a receptor layer, which is dissolved or dispersed in a solvent, is applied and dried to form a receptor layer. In this drying step, the weight of the solvent in the receptor layer is 1% of the weight of the resin for forming the receptor layer. A method for producing a heat-receiving sheet, comprising removing the solvent as described below.