JP2010083000A - Thermosensitive transfer sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosensitive transfer sheet, in which image defect is few due to the small elongation of the thermosensitive transfer sheet at a self-service high-speed print and the discoloration of prints is few during the storage of the thermosensitive transfer sheet in a roll due to the suppression of dye transfer from a dye layer to a heat-resistant lubricant-layer. <P>SOLUTION: In the thermosensitive transfer sheet, which is formed by providing the dye layer including thermally transferable coloring matter and resin on one side of a base material film and the heat-resistant lubricant-layer including lubricant and resin on the other side thereof, the heat-resistant lubricant-layer includes phosphate having a specific OH group and/or the salt of a specific phosphate as lubricant and, at the same time, when the characteristic X-ray intensity due to the K ray of phosphor element in the heat-resistant lubricant-layer obtained by irradiating with electron beam accelerated to 20 kV and throttled to a beam diameter of ≤1 μm from the heat-resistant lubricant-layer side of the thermosensitive transfer sheet is measured with an energy dispersion type X-ray spectroscope at various spots in a square 200×200 μm region, the greatest value among the intensities in the region is set to be ≥2.5 times as much as the least value thereamong and a plurality of extremum (maximum) regions having extrema (maxima) of the characteristic X-ray intensity due to the K ray of phoshor element exist within the region and the coefficient of variation, which is calculated by dividing the standard deviation of the extrema (maxima) of the characteristic X-ray intensity among the extrema (maxima) regions with the average of the characteristic X-ray intensities, is set to be ≤0.25. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermal transfer sheet, and more specifically, the thermal transfer sheet has few image defects due to small elongation of the thermal transfer sheet during high-speed printing, and suppresses dye transfer from the dye layer to the heat-resistant slipping layer. The present invention relates to a heat-sensitive transfer sheet with little discoloration of print even when stored in a roll form.

Conventionally, various thermal transfer recording methods are known. Among them, the dye diffusion transfer recording method is attracting attention as a process capable of producing a color hard copy closest to the image quality of a silver salt photograph. In addition, it has advantages over silver halide photography, such as being dry, making visible images directly from digital data, and making replicas easier.
In this dye diffusion transfer recording system, a heat-sensitive transfer sheet (hereinafter also referred to as an ink sheet) containing a dye and a heat-sensitive transfer image-receiving sheet (hereinafter also referred to as an image-receiving sheet) are superposed, and then heat is generated by an electrical signal. The ink sheet is heated by a controlled thermal head or the like, and the dye in the ink sheet is transferred to the thermal transfer image-receiving sheet to record image information, and the three colors of cyan, magenta, and yellow are overlaid. Thus, a color image having a continuous change in color shading can be transferred and recorded.

  In recent years, in the field of dye diffusion transfer recording system, various printers capable of printing at a higher speed than before have been developed and spread to the market. High-speed printing is a performance required for reducing the waiting time when a user prints at a store.

The thermal transfer sheet on the side in contact with the thermal printer head of the printer is provided with a heat-resistant slipping layer for the purpose of preventing seizure of the thermal printer head and the thermal transfer sheet and imparting slidability between the thermal printer head and the ink sheet. ing. The image sticking causes the thermal transfer sheet to be cut at the time of printing. On the other hand, if the slipping property is insufficient, an image defect may be caused at the time of printing by deformation of the thermal transfer sheet or wrinkles. Since the thermal printer head comes into contact with the heat resistant slipping layer at a higher temperature and higher speed by high speed printing, further improvement in the performance of the heat resistant slipping layer is required.
For example, Patent Document 1 discloses that a phosphate ester-based surfactant is added to the heat-resistant slip layer in order to improve the slip property, and Patent Document 2 discloses that a specific phosphate ester zinc is used to impart lubricity. The inclusion of a salt is disclosed.
JP-A-8-90942 Japanese Patent No. 2655544

When the performance of the heat-resistant slipping layer at the time of high-speed printing is examined using the above-mentioned phosphate ester surfactant and phosphate ester zinc salt, the printer waits for 10 minutes or more after printing and then starts printing again It was found that the thermal transfer sheet was particularly large in the first to fifth sheets. On the other hand, when ensuring the slip between the thermal printer head and the heat-resistant slip layer of the thermal transfer sheet and suppressing the expansion of the ink sheet during printing, the dye is transferred from the dye layer to the heat-resistant slip layer side. It turns out that it becomes easy to do.
When accepting images from a plurality of general customers and printing a large number of images continuously, only the first five image defects are generated. However, in the case of self-service where a general customer prints at a store, since the printer often prints again after waiting for 10 minutes or more, even if the printing is started again after the standby, There has been a demand for an improvement that can more effectively suppress the elongation of.
On the other hand, in the production process of the thermal transfer sheet, after coating the dye layer on the base film, it is dried and wound up and stored once in the form of a roll, then pulled out from the roll, cut to the desired width, and wound up again. As a roll form, it is stored as a product form to be set in the printer. In these roll forms, the dye layer and the heat resistant slipping layer are in contact with each other, so that the dye can be transferred to the heat resistant slipping layer. In the roll form after drying, the dye is transferred to the heat resistant slipping layer, and the dye transferred to the heat resistant slipping layer in the roll form of the product form is further transferred back to the dye layer side, whereby the amount of dye on the dye layer side and the dye When the position where the coating is applied deviates from the setting, discoloration of the obtained print occurs. In this respect, further improvement of the thermal transfer sheet has been demanded.

  Accordingly, an object of the present invention is to provide an image with few image defects due to small elongation of the thermal transfer sheet in self-service high-speed printing, and to suppress dye transfer from the dye layer to the heat resistant slipping layer. Another object of the present invention is to provide a thermal transfer sheet that can obtain a print with little discoloration even when the thermal transfer sheet is stored in a roll form.

As a result of intensive studies, the present inventors have found that the above object of the present invention can be achieved by the following means.
(1) A heat-sensitive transfer sheet having a dye layer containing a thermally transferable pigment and resin on one surface of a substrate film and a heat-resistant slip layer containing a lubricant and a resin on the other surface, The photosensitive layer contains a compound represented by the following general formula (1) as a lubricant, and is obtained by irradiating an electron beam with a beam diameter of 1 μm or less accelerated to 20 kV from the heat-resistant slipping layer side of the thermal transfer sheet. When the characteristic X-ray intensity derived from the K-line of the phosphorus element in the heat-resistant slip layer is measured by an energy dispersive X-ray spectrometer at each point in the 200 μm square area, the maximum of the intensity in the area There are a plurality of maximum regions having a maximum value of characteristic X-ray intensity derived from phosphorus element K-rays in the region at least 2.5 times the minimum value, and the characteristics between these maximum regions The standard deviation of the maximum value of X-ray intensity is Thermal transfer sheet variation coefficient obtained by dividing the average sex X-ray intensity is equal to or is 0.25 or less.

General formula (1)
{(R ¹ O) (R ² O) P (═O) O} _m M

(In General Formula (1), M represents a hydrogen atom, a metal ion, or an ammonium ion. R ¹ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aryl group. R ² represents Represents a hydrogen atom, a metal ion, an ammonium ion, or a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aryl group, and m is the same as the valence of M and represents a number of 1 to 6.
(2) The thermal transfer according to (1), wherein the maximum value of the intensity is at least 3.0 times the minimum value, and the coefficient of variation of the distribution is 0.22 or less. Sheet.
(3) The melting point of at least one compound represented by the general formula (1) contained in the heat-resistant slipping layer is 40 ° C to 100 ° C, (1) or (2) Thermal transfer sheet.
(4) The heat-sensitive transfer sheet according to any one of (1) to (3), wherein the heat-resistant slipping layer further contains a polyvalent metal salt of an alkyl carboxylic acid.
(5) The heat-sensitive transfer sheet according to any one of (1) to (4), wherein the heat-resistant slipping layer further contains talc particles.
(6) The relationship between the content of the talc particles and the content of the compound represented by the general formula (1) is such that the content of the compound represented by the general formula (1) is 100 parts by mass. In this case, the heat-sensitive transfer sheet according to (5), wherein the content of the talc particles is 30 parts by mass or more.
(7) The heat-sensitive transfer sheet according to any one of (1) to (6), wherein the base film has an easy-adhesion layer on at least one surface of the base film.
(8) The resin according to any one of (1) to (7), wherein the resin of the heat resistant slipping layer has two or more hydroxyl groups in a polymer chain length terminal or a polymer structure of the resin. Thermal transfer sheet.
(9) The thermal transfer sheet according to (8), wherein the resin is a polyacryl polyol resin.
(10) The heat-sensitive transfer sheet according to (8) or (9), wherein the resin of the heat-resistant slipping layer is crosslinked.
(11) The thermal transfer sheet according to (10), wherein the crosslinking reaction in the crosslinking is performed in a temperature range of 40 ° C. to 53 ° C. and a period of 1 day to 20 days.
(12) The thermal transfer sheet is a thermal transfer sheet used in combination with a thermal transfer image-receiving sheet having a heat insulating layer containing a hollow polymer latex and a receiving layer containing a polymer latex on a support. The heat-sensitive transfer sheet according to any one of (1) to (11), which is characterized.
(13) A heat-sensitive transfer image-receiving sheet having a heat insulating layer containing a hollow polymer latex and a receiving layer containing a polymer latex on a support, and a dye layer containing a dye and a resin that can be thermally transferred to one surface of a substrate film And a heat-sensitive transfer sheet on which the heat-resistant slip layer containing a lubricant and a resin is formed on the other side of the heat-sensitive transfer image-receiving sheet and the dye layer of the heat-sensitive transfer sheet are in contact with each other. And an image forming method for forming an image by applying thermal energy corresponding to an image signal from the heat-resistant slipping layer side of the heat-sensitive transfer sheet, wherein the heat-sensitive transfer sheet is used as a lubricant in the heat-resistant slipping layer. The heat resistance obtained by irradiating an electron beam having a beam diameter of 1 μm or less containing a compound represented by the following general formula (1) and accelerated to 20 kV from the heat resistant slipping layer side of the thermal transfer sheet. When the characteristic X-ray intensity derived from the K-line of the phosphorus element in the active layer is measured by an energy dispersive X-ray spectrometer at each point in the 200 μm square area, the maximum value of the intensity in the area is There are a plurality of maximum regions having a maximum value of the characteristic X-ray intensity derived from the phosphorus element K-ray in the region at least 2.5 times the minimum value, and the characteristic X-ray intensity between these maximum regions A variation coefficient obtained by dividing the standard deviation of the local maximum value by the average of the characteristic X-ray intensity is 0.25 or less.
General formula (1)
{(R ¹ O) (R ² O) P (═O) O} _m M
(In General Formula (1), M represents a hydrogen atom, a metal ion, or an ammonium ion. R ¹ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aryl group. R ² represents Represents a hydrogen atom, a metal ion, an ammonium ion, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aryl group, and m is the same as the valence of M and represents a number of 1 to 6.

  According to the present invention, the thermal transfer sheet has a small elongation at the time of self-service high-speed printing, can give an image with less image defects, and suppresses dye transfer from the dye layer to the heat-resistant slipping layer, thereby enabling thermal transfer. It is possible to provide a thermal transfer sheet capable of obtaining a print with little discoloration even when the sheet is stored in a roll form.

Hereinafter, the present invention will be described in detail.
1) Thermal transfer sheet (Configuration of thermal transfer sheet (ink sheet))
The ink sheet is placed on the thermal transfer image-receiving sheet during thermal transfer image formation, and the dye (pigment) is transferred from the ink sheet to the thermal transfer image-receiving sheet by heating from the ink sheet side with a thermal printer head or the like. Used. The ink sheet of the present invention has a dye layer containing a thermally transferable dye and resin (hereinafter also referred to as a thermal transfer layer or a thermal transfer layer) on one side of the base film of the ink sheet, and on the other side, It has a heat-resistant slipping layer containing a lubricant and a resin. An easy adhesion layer (primer layer) may be provided between the base film and the dye layer and / or between the base film and the heat-resistant slip layer.

(Heat resistant slipping layer)
In the present invention, the heat resistant slipping layer contains a phosphate ester having an OH group or a phosphate ester salt as a lubricant.
Although the preferable aspect is illustrated about the phosphate ester or salt of phosphate ester which has OH group of this invention below, this invention is not limited to these examples.

(Phosphate ester having OH group)
The phosphoric acid ester having an OH group used in the present invention is such that three phosphoric acid groups (OH) per molecule of phosphoric acid are esterified at one place (monoester) or two places (diester). OH groups (hydroxyl groups) that are not esterified remain.

(Phosphate salt)
With the salt of the phosphate ester used in the present invention, esterification is performed at one place (monoester) or two places (diester) with respect to three OH groups bonded to a phosphorus atom per phosphoric acid molecule, A compound in which one of the hydrogen atoms of an unesterified OH group is replaced with a metal ion or an ammonium ion.

  As the phosphoric acid ester having the OH group and the salt of the phosphoric acid ester, a compound represented by the following general formula (1) is preferable.

General formula (1)
{(R ¹ O) (R ² O) P (═O) O} _m M

In the formula, M represents a hydrogen atom, a metal ion, or an ammonium ion, R ¹ represents an aliphatic group or an aryl group, and R ² represents a hydrogen atom, a metal ion, an ammonium ion, an aliphatic group, or an aryl group. These aliphatic groups and aryl groups may have a substituent. m is the same as the valence of M and represents a number of 1 to 6.
Examples of the substituent that may be substituted by the aliphatic group or aryl group include an aliphatic group (alkyl group, alkenyl group, alkynyl group, cycloalkyl group, cycloalkenyl group, cycloalkynyl group, etc.), aryl group ( Phenyl group, naphthyl group, etc.), heterocyclic group, halogen atom, hydroxyl group, alkoxy group, alkenoxy group, cycloalkoxy group, cycloalkenoxy group, aryloxy group, heterocyclic oxy group, mercapto group, alkylthio group, alkenyl Thio group, arylthio group, amino group, alkylamino group, arylamino group, heterocyclic amino group, acylamino group, sulfonamide group, imide group, cyano group, nitro group, carboxyl group, sulfo group, carbamoyl group, sulfamoyl group, etc. Is mentioned.
Examples of the aliphatic group in R ¹ and R ² include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, and a cycloalkenyl group, and examples of the aryl group include a phenyl group and a naphthyl group. Moreover, these substituents may be further substituted with these substituents.
R ¹ is preferably an aliphatic group, more preferably an alkyl group or an alkenyl group, and R ² is preferably a hydrogen atom or an aliphatic group, preferably a hydrogen atom, an alkyl group or an alkenyl group. These aliphatic groups, alkyl groups, and alkenyl groups may have the above-described substituents.
When R ¹ or / and R ² is an aliphatic group, the following groups are preferred.

R ^{11 to} R ¹⁴ each independently represents a hydrogen atom or a substituent. Examples of the substituent include substituents that the aliphatic group or aryl group of R ¹ and R ² in the general formula (1) may have. R ^{11 to} R ¹⁴ are preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom. n represents the number of 0-20, and 1-8 are still more preferable. R ¹⁵ represents an aliphatic group or an aryl group.
The aliphatic group for R ¹⁵ is preferably an alkyl group or an alkenyl group, and the number of carbon atoms is preferably 6 to 20, and more preferably 12 to 18. R ¹⁵ may have a substituent, and examples of the substituent include a substituent that the aliphatic group or aryl group of R ¹ and R ² in the general formula (1) may have. However, an unsubstituted aliphatic group is preferred.
Examples of the aryl group for R ¹⁵ include a phenyl group and a naphthyl group. The aryl group may have a substituent, and examples thereof include an aliphatic group of R ¹ and R ² in the general formula (1) and a substituent that the aryl group may have. Among them, an alkyl group is preferable. . In this case, the alkyl group preferably has 6 to 20 carbon atoms, and more preferably 12 to 18 carbon atoms.
R ¹⁵ is preferably an aliphatic group, more preferably a stearyl group or an oleyl group.
Further, n is preferably 0 in the present invention.
Among the phosphate esters having an OH group, phosphate monoesters or diesters having an alkyl group having 12 to 18 carbon atoms are more preferred.

The metal ions in M and R ² may be monovalent metal ions or polyvalent metal ions. As monovalent metal ions, alkali metal ions are preferable, lithium ions, sodium ions and potassium ions are more preferable, and sodium ions are most preferable. The polyvalent metal ion is any polyvalent metal ion other than alkali metal ions, such as magnesium ion, calcium ion, zinc ion, copper ion, lead ion, aluminum ion, iron ion, cobalt ion, chromium ion and manganese. Examples thereof include magnesium ion, calcium ion, zinc ion and aluminum ion, and zinc ion is most preferable.
The ammonium ion is preferably an ion represented by the following general formula.
⁺ N (R ^A1 ) (R ^A2 ) (R ^A3 ) (R ^A4 )
In the above, R ^{A1 to} R ^A4 each independently represent a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent. The substituent which the aliphatic group of R < ¹ >, R < ² > and an aryl group in 1) may have is mentioned. Of these substituents, a hydroxyl group and a phenyl group are preferable. Further, any two to three groups of R ^{A1 to} R ^A4 are bonded to each other to form a ring (eg, pyrrolidine ring, piperidine ring, morpholine ring, piperazine ring, indoline ring, quinuclidine ring, pyridine ring). Also good.
R ^{A1 to} R ^A4 are preferably a hydrogen atom or an alkyl group which may have a substituent.
Examples of ammonium ions include NH ₄ ⁺ , NH (CH ₂ CH ₂ OH) ₃ ⁺ , NH ₃ (CH ₂ CH ₂ OH) ⁺ , morpholinium, N (CH ₂ CH ₂ OH) ₄ ⁺ , NH ₃ (C ₄ H ₉ ) ⁺ is preferable, and NH ₄ ⁺ , NH ₃ (CH ₂ CH ₂ OH) ⁺ , and morpholinium are more preferable.

  In the present invention, the phosphoric acid ester having the OH group and / or the phosphoric acid ester salt contains the compound represented by the general formula (1), but these may be used alone, Can be used in combination.

Many of these phosphoric acid esters are commercially available. For example, NIKKOL DLP-10, NIKKOL DOP-8NV, NIKKOL DDP-2, NIKKOL DDP-4, NIKKOL DDP-6, NIKKOL DDP of Nikko Chemicals Co., Ltd. -8, NIKKOL DDP-10, Daiichi Kogyo Seiyaku Co., Ltd. Prisurf AL, Prisurf A208F, Prisurf A208N, Prisurf A217E, Prisurf A219B, Toho Chemical Co., Ltd. Phosphanol RB410, Phosphor Nord RB710, Phosphanol GF199, Phosphanol LP700, Phosphanol LB400, Phoslex A-8, Phoslex A-18, Phoslex A-18D (all trade names) from Sakai Chemical Industry Co., Ltd. I can get lost.
In addition, dilauryl phosphate ester, dioleyl phosphate ester, distearyl phosphate ester, and di (polyoxyethylene dodecyl phenyl ether) phosphate are exemplified.

Many of the phosphate ester salts are commercially available. For example, Prisurf M208B and Prisurf M208F from Daiichi Kogyo Seiyaku Co., Ltd., Phosphanol RD720, Phosphanol GF185 from Toho Chemical Co., Ltd. , Phosphanol GF215, Phosphanol RS710M, Phosphanol SC6103, Sakai Chemical Industry's LBT-1830, LBT-1830 purified product, LBT-2230, LBT-1813, LBT-1820 (all trade names) Is mentioned.
Other than this, zinc salt of dilauryl phosphate ester, zinc salt of dioleyl phosphate ester, zinc salt of distearyl phosphate ester, sodium di (polyoxyethylene nonyl ether) phosphate, di (polyoxyethylene dodecyl phenyl ether) phosphate , Sodium di (polyoxyethylene decylphenyl ether) phosphate, and the like.

  The total coating amount of the phosphoric acid ester having an OH group and the salt of the phosphoric acid ester of the present invention is preferably 1% or more and 25% or less of the total coating mass of the heat resistant slipping layer, and preferably 2% or more and 15% or less. More preferably. In addition, it is also preferable to use a combination of a phosphate ester having an OH group and a phosphate ester salt of the present invention. If these OH group-containing phosphate esters and phosphate ester salts are solid and have low or no solubility in the heat resistant slipping layer coating solution, dispersion in the heat resistant slipping layer coating solution In order to speed up or stabilize the powder, it is preferable to use a powder form in advance, and the particle size is preferably 0.1 μm to 100 μm, more preferably 1 μm to 30 μm.

Next, a method for measuring the characteristic X-ray intensity derived from the K-ray of the phosphorus element of the heat resistant slipping layer defined in the present invention will be described.
(Characteristic X-ray intensity)
In principle, the characteristic X-ray intensity measurement method measures the intensity of characteristic X-rays obtained by exciting atoms in a sample by electron beam irradiation, and will be described in detail below.
(Electron beam irradiation)
The electron beam to be irradiated has an acceleration voltage of 20 kV and a beam diameter of 1 μm or less in order to ensure resolution. Even if the acceleration voltage increases or decreases, the characteristic X-ray intensity derived from the phosphorus element decreases, and at the same time, the baseline noise also increases, so that the accurate intensity cannot be measured. Since the electrons are scattered in the sample by the irradiation of the beam, the spatial resolution becomes larger than the beam diameter. Although electron scattering varies depending on the type of element, in the present invention, if the acceleration voltage is 20 kV, the depth direction is about 5 μm, the width direction is about 10 μm, and the beam diameter is 1 μm or less, there is no difference in spatial resolution. In order to increase the characteristic X-ray intensity to be measured, the current amount is usually increased, but at the same time, the beam diameter is increased. A field emission electron gun is used as an electron source because a larger current can be obtained and a beam diameter increase due to an increase in current amount is small. Since the amount of current and the characteristic X-ray intensity are proportional, the amount of current is kept constant.

(Characteristic X-ray measurement)
Wavelength dispersive X-ray spectroscopy (abbreviation “WDS” or “WDX”) and energy dispersive X-ray spectroscopy (abbreviation “EDS” or “EDS”) are used as measurement methods. EDX "). Although each of the measurement methods has characteristics, energy dispersive X-ray spectroscopy is used in the present invention because it is excellent in analysis of a minute region and analysis time is short. In the present invention, the measurement time at one place can be carried out in about 1 to 10 minutes. There are three types of characteristic X-rays of phosphorus element: Kα1 line (2.014 keV), Kα2 line (2.013 keV), and Kβ1 line (2.139 keV). In energy dispersive X-ray spectroscopy, each overlaps. Since it is detected as one peak, this is called K-line. The characteristic X-ray intensity derived from the K-line of the phosphorus element of the present invention is the K-line intensity of the phosphorus element. When measuring characteristic X-ray intensity derived from phosphorus element K-rays at a plurality of locations on the same sample, it is preferable to keep the measurement time constant in addition to the current amount.

A device equipped with an energy dispersive X-ray spectrometer (abbreviated as “SEM-EDX”) in a scanning electron microscope (abbreviated as “SEM”) for the purpose of being able to use an electron beam source and confirming the measurement position. , “SEM-EDS”) is preferable.
Specifically, the sample is first subjected to SEM measurement to confirm that the electron beam is sufficiently focused, and the same region is scanned and measured with an EDX (energy dispersive X-ray spectrometer) to perform elemental mapping of phosphorus. carry out. Elemental mapping by EDX is a method in which characteristic X-rays are measured in a short period of time while scanning with an electron beam, and mapping is performed, and points with high and low phosphorus element content are roughly selected from the mapping image. I can do it. An accurate relative intensity at each point can be measured by fixing the electron beam without scanning at each selected point and measuring the characteristic X-ray intensity derived from the phosphorus element K-ray.
Here, the obtained intensity value is taken on a plane parallel to the support (two-dimensional distance plane, X axis and Y axis orthogonal to each other), and the vertical axis (Z axis) orthogonal to this plane is the phosphorus element K line. When a three-dimensional space with the characteristic X-ray intensity derived is plotted, there are a plurality of peaks (the peak is a maximum value) and valleys (the valley bottom is a minimum value) of the intensity value.
In the present invention, the maximum region of the characteristic X-ray intensity includes at least one maximum value of the characteristic X-ray intensity (one peak of the intensity value in the three-dimensional space plot) and is adjacent to the point of the maximum value. Characteristic X-rays with a maximum value (maximum value) of 1.5 times or more of the minimum value (minimum value) with respect to a point having a low characteristic X-ray intensity surrounding the periphery (the minimum value is the above-mentioned valley bottom) It is a local maximum region having a local maximum value (region including the lowest part (minimum value) of the valley from the peak part). Here, if it is less than 1.5 times, the same verification is performed in a wider surrounding area, the distance plane is expanded until the requirement of 1.5 or more is satisfied, and the point where the characteristic X-ray intensity is the lowest A maximum region in which the relationship between (the lowest point in the maximum region) and the point having the highest characteristic X-ray intensity (the highest point in the maximum region) satisfies the relationship of 1.5 times or more is obtained. For this reason, the maximum areas of individual characteristic X-ray intensities have different distance plane areas, and there may be a plurality of local maximum values and local minimum values (mountains and valley bottoms) in one local area of the characteristic X-ray intensity. . In this way, a region satisfying the above requirements is defined as one maximum region of characteristic X-ray intensity. In the measurement method of the present invention, as described above, since the scattering of the electron beam in the width direction is about 10 μm, the distance between the points showing the maximum value in the maximum region of the characteristic X-ray intensity is at least 4 μm or more away from the spatial resolution. Yes.
In the present invention, the maximum value of characteristic X-ray intensity (hereinafter also referred to as “maximum characteristic X-ray intensity”) is the highest characteristic X-ray intensity measured in the maximum area (one maximum area). Is a maximum value among one or a plurality of maximum values included in (i.e., an intensity value corresponding to the peak of the highest mountain).
The maximum value and the minimum value of the characteristic X-ray intensity derived from the phosphorus element K-ray in the 200 μm square area are the largest and smallest values of the characteristic X-ray intensity in the 200 μm square area. In general, the minimum value can be determined by selecting a total of 10 to 20 points having a low phosphorus element content and irradiating with an electron beam. On the other hand, the maximum value can be obtained by irradiating the center of each region having a high phosphorus element content with an electron beam.
In the present invention, since the region having a high phosphorus element content is generally raised, the region raised by the SEM measurement is specified in advance, and the region having a high phosphorus element content can be roughly determined. In the present invention, the acceleration voltage can be 2 to 5 kV for SEM measurement of the surface shape.

(Sample preparation for measurement)
When the sample is charged by irradiating the sample with an electron beam, the electron beam fluctuates due to the electric field due to the charge, and the current value of the electron beam also fluctuates, so accurate measurement cannot be performed. In order to prevent charging, the surface of the sample is usually covered with a conductive thin film to prevent charging. The conductive thin film is generally preferably formed by coating carbon (C) with a thickness of 20 nm to 35 nm by sputtering.
For more detailed explanation, “Surface analysis technology selection electronic probe microanalyzer edited by Japan Surface Science Society” published by Maruzen Co., Ltd., 1998, EPMA Electron probe microanalyzer electronic probe microanalyzer by Shinobu Kinouchi, Technical Institute, 2001 Are listed.

(Characteristic X-ray intensity derived from phosphorus element K-line in heat-resistant slip layer)
In the present invention, in the characteristic X-ray intensity derived from phosphorus element K-rays at each point in the heat-resistant slipping layer measured by the above method, with respect to the minimum value of the characteristic X-ray intensity in the 200 μm square area. The maximum value of the characteristic X-ray intensity in the region is preferably 2.5 times or more (preferably 10.0 times or less), preferably 3.0 times or more (preferably 8.0 times or less). Is more preferable. The larger this value, the more non-uniform and localized the phosphate ester or phosphate ester salt having an OH group is in the heat resistant slipping layer. In the present invention, a region in which the phosphate ester or phosphate ester salt having such an OH group is localized in the heat-resistant slipping layer (the above-mentioned maximum region of the characteristic X-ray intensity, that is, the above-mentioned property There are a plurality of regions having a maximum value of 1.5 times or more the minimum value of the X-ray intensity, and the number of these regions is preferably 10 to 1000 with respect to a 200 μm square region, and 20 -500 is most preferred. It is preferable that the variation in the characteristic X-ray intensity derived from the phosphorus element K-ray corresponding to the localized region of the phosphate ester or phosphate ester salt having an OH group (the aforementioned maximum value of the characteristic X-ray intensity) is small. The coefficient of variation (calculation method will be described later) corresponding to each localized region of a phosphate ester or phosphate ester salt having an OH group present in a 200 μm square region is preferably 0.25 or less. 0.22 or less is more preferable, and 0.20 or less is most preferable. Further, the total number of localized regions of phosphate esters or phosphate ester salts having OH groups in the range of 0.7 to 1.3 times the average of the maximum value of the characteristic X-ray intensity is 80 in total. % Or more, preferably 90% or more, and most preferably 98% or more.
A variation coefficient of distribution can be obtained from the average of the maximum value of the characteristic X-ray intensity and the standard deviation. The calculation formula is as follows.
Formula (1) (Average of maximum value of characteristic X-ray intensity) = (Total sum of maximum value of characteristic X-ray intensity) / (Total number of measurements taking the sum)
Formula (2) (Standard deviation) = {[(Maximum value of each characteristic X-ray intensity) − (Average of maximum value of characteristic X-ray intensity)] / (Sum of squares) / (Total number of measurements taken) } To the power of 0.5 (3) (Coefficient of variation) = (Standard deviation) / (Average of local maximum value of characteristic X-ray intensity)

  In the present invention, the phosphate ester or phosphate ester salt having an OH group is used for imparting slipperiness to the heat resistant slipping layer, and slipping can be achieved by increasing the content in the heat resistant slipping layer. It is possible to improve the property and reduce the elongation of the thermal transfer sheet during high-speed printing, but at the same time, the dye transfer to the heat resistant slipping layer is increased. According to the present invention, the characteristic X-ray intensity derived from the phosphorus element K-ray is measured according to the method described in detail hereinabove, and as a result, with respect to the minimum value of the maximum value of the characteristic X-ray intensity in the predetermined region. The ratio value is within the predetermined range defined in the present invention, the presence of a plurality of maximum regions having the maximum value of the characteristic X-ray intensity derived from the phosphorus element K-line, and the maximum value of the characteristic X-ray intensity The thermal transfer sheet elongation during high-speed printing is satisfied only when all the conditions that the coefficient of variation obtained by the above formulas (1) to (3) are within the predetermined range defined in the present invention are satisfied. Is excellent, and the dye transfer from the dye layer to the heat-resistant slipping layer can be suppressed. Here, satisfying any of the above three conditions is also referred to as “a predetermined phosphate ester having an OH group or a salt thereof satisfies a predetermined distribution state defined in the present invention”.

Next, the manufacturing method of the coating liquid for heat-resistant slip layers prescribed | regulated in this invention is described.
Since the coating liquid for the heat-resistant slipping layer is a liquid having a particulate region that is not dispersed in a molecular state in the liquid, a method for producing a pigment dispersion used in the paint industry can be used.
In general, the production process can be roughly divided into a dissolution process and a dispersion process. The dissolution step is a step of dissolving a component that dissolves in the solvent for the coating solution in the heat resistant slipping layer component to form a solution, and generally involves dissolving the resin in an organic solvent. . A dispersion | distribution process is a process which mixes and disperse | distributes the said solution and the component which does not melt | dissolve completely in the solvent for coating liquids in a heat-resistant slipping layer component. In many cases, the component that does not completely dissolve in the solvent for the coating liquid is a secondary agglomerated powder. In the dispersion step, (1) a step of wetting the powder surface with a solution, (2) agglomerated powder. A step of loosening the particles into primary particles or crushing the primary particles, and (3) a step of stabilizing the dispersed particles. In the step (1), it is preferable that the powder surface is easily wetted with the solution, and the air on the surface of the powder is replaced with the solution, so that high pressure or high shear force (shear stress) is preferable as the dispersion condition. . In the step (2), a high shearing force is required as a dispersion condition in order to solve the powder aggregation. In order to prevent the dispersed particles from re-aggregating in the liquid in the step (3), and also to prevent re-aggregation even when the coating liquid is dried after coating and the solvent disappears, Various additives can be added. Usually, the steps (1) to (3) proceed simultaneously in the same dispersion apparatus, but it is also preferable to provide a step (premixing) in which the step (1) is performed in advance. When the heat resistant slipping layer is formed by curing the resin with a crosslinking agent, the coating can generally be carried out by adding the crosslinking agent to the liquid after dispersion before coating.

  A well-known thing can be used as a dispersion apparatus used for the said dispersion | distribution. For example, a three-roll mill disperses using shear force and pressing pressure acting on the contact between rolls with different rotational speeds, and a sand mill and bead mill stir media such as glass beads and zirconia beads in a container. It is dispersed using the impact force and shear stress obtained by this. The impact force and shear stress are limited because the media agitation in the bead mill is due to gravity, so that a strong impact force and shear stress can be obtained by forcibly agitating with the arm that rotates the media. There is an improved attritor. In addition to the above, for small-volume dispersion, in addition to the paint shaker that shakes and mixes small containers and the impact force and shear stress of the bead mill are limited, the container is forced to rotate and revolve simultaneously to force the media. There are planetary type bead mills and the like which are improved so as to obtain a strong impact force and shear stress by stirring them. For more detailed explanations, see “Paint Flow and Pigment Dispersion” issued by Kyoritsu Publishing Co., Ltd., 1992, “Paints and Painting (Enhanced Edition)”, Power Corporation, 1994, “Emulsification / Dispersion Theory and practice Theories "published by Tokushu Kagaku Kogyo Co., Ltd., 1997, and" Introduction to Printing Ink, Revised Edition ", published by the Printing Society of Japan Press, 2002.

In the present invention, the phosphate ester or phosphate ester salt having the OH group used for imparting slipperiness to the heat-resistant slipping layer has low solubility in the solution, and therefore the heat-resistant slipping layer. It is considered that the dispersed particles are in a state of dispersed particles in the coating liquid for use, and the dispersed particles are also formed in the heat-resistant slip layer formed by drying the coating liquid after coating. Further, as described above, in the dispersion process, by applying a high shearing force, heat may be generated, and further primary particles may be pulverized. Although it is possible to control the temperature as a bulk through the heat medium in the outer wall of the container and the stirring blade against the heat generation, the heat generation at the microscopic interface between the rolls or the microscopic region of the bead interface that generates shearing force is completely achieved. It cannot be suppressed to. For this reason, it is considered that the phosphate ester or phosphate ester salt having an OH group is dissolved by heat generation in a microscopic high shear force region and then precipitated during the dispersion step. In order to control the dissolution and precipitation to facilitate the control of the dispersion state, it is preferable to use at least one OH group-containing phosphate ester or phosphate ester salt having a melting point of 40 ° C. to 100 ° C. More preferably, the melting point is 50 ° C to 90 ° C.
For the above-described reasons, the state of dispersed particles in the heat-resistant slip layer generally does not match the particle size and shape of the raw material powder. Furthermore, since the dispersion conditions vary greatly depending on the composition of the coating liquid, the production scale, and the dispersion apparatus, they are not uniformly determined. For this reason, in the present invention, the dispersion state in the heat resistant slipping layer is defined by the characteristic X-ray intensity measurement.

In the present invention, additives such as other lubricants, plasticizers, stabilizers, fillers and fillers may be used in combination with the heat-resistant slip layer.
As fillers, fluorides such as calcium fluoride, barium fluoride, and graphite fluoride, sulfides such as molybdenum disulfide, tungsten disulfide, and iron sulfide, oxides such as silica, colloidal silica, lead oxide, alumina, and molybdenum oxide , Inorganic such as graphite, mica, boron nitride, magnesium oxide (magnesia), magnesium hydroxide (brucite), magnesium carbonate (magnesite), magnesium calcium carbonate (dolomite), clays (talc, kaolin, acid clay, etc.) Fillers made of compounds, organic resins such as fluororesins and silicone resins, silicone oils, alkylcarboxylic acid polyvalent metal salts (such as zinc stearate and lithium stearate), various waxes such as polyethylene wax and paraffin wax, anions Surfactants On surfactant, amphoteric surface active agents include nonionic surface active agents, a surfactant such as a fluorine-based surfactant. The particle size of the filler is preferably 0.1 μm to 50 μm, more preferably 0.5 μm to 10 μm, and the filler particle shape may be any shape such as indefinite shape, spherical shape, cube shape, needle shape, or flat plate shape. However, needles and flat plates are preferably used.
Among these additives that can be used in combination, magnesium oxide, magnesium hydroxide, talc, kaolin and alkylcarboxylic acid polyvalent metal salt are preferable, and magnesium oxide, talc and alkylcarboxylic acid polyvalent metal salt are more preferable. Of these, zinc stearate is more preferable as the alkylcarboxylic acid polyvalent metal salt.
Here, in order to achieve the effect of the present invention more effectively, talc (talc particles) or alkylcarboxylic acid polyvalent metal salt is preferably used, and talc (talc particles) and alkylcarboxylic acid polyvalent metal salt are used. It is particularly preferred to use both.

Talc is a hydrated silicate mineral of magnesium, and the theoretical composition is Mg ₃ Si ₄ O ₁₀ (OH) ₂ . The unit structure is a three-layer structure in which a magnesium-containing layer is sandwiched between two layers of a silicate layer structure, and has a cleavage property because the bond between the silicate layers between the unit structures is weak. (Mohs hardness 1) and slipperiness. In addition, since it does not decompose to around 900 ° C. and is inert to most chemicals, it is a thermally and chemically stable substance. There are two types of talc, monoclinic and triclinic. In the present invention, any talc can be used, and a mixture of monoclinic and triclinic is also used. be able to.
The inclusion of talc in the heat-resistant slip layer makes it difficult to damage the thermal printer head due to the softness of talc. It is useful because it is less affected by fusion and corrosion on the thermal printer head.

As the talc, commercially available powdered talc derived from natural minerals can be used. For example, the Micro Ace series, SG series manufactured by Nippon Talc Co., Ltd. ) List PS series manufactured by Fukuoka Talc Kogyo, JET series manufactured by Asada Flour Milling Co., Ltd., Hytron series manufactured by Takehara Chemical Industry Co., Ltd. I can do it. In the present invention, the average sphere equivalent particle size of the talc particles is preferably 0.5 to 10 μm, more preferably 0.8 to 5 μm, and most preferably 1 to 4 μm. The average sphere equivalent particle size of talc can be determined by a laser diffraction scattering method.
In the present invention, the relation of the content of talc in the heat resistant slipping layer is preferably 30 parts by mass or more when the total content of the phosphoric acid ester having the OH group and the salt of the phosphoric acid ester is 100 parts by mass. 40 parts by mass or more is more preferable, and 50 parts by mass or more is more preferable. The upper limit is preferably 1000 parts by mass or less, more preferably 500 parts by mass or less, and still more preferably 400 parts by mass or less.

In the alkylcarboxylic acid polyvalent metal salt, the alkylcarboxylic acid is preferably an alkylcarboxylic acid having 8 to 25 carbon atoms, more preferably 12 to 21 carbon atoms, and more preferably 14 to 20 carbon atoms, such as octanoic acid, Examples thereof include lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid. Examples of the polyvalent metal include divalent or trivalent metals such as alkaline earth metals and transition metals, such as calcium and magnesium. , Barium, strontium, cadmium, aluminum, zinc, copper, iron and the like. Among them, zinc is preferable. Alkylcarboxylic acid polyvalent metal salts include zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc behenate, calcium stearate, magnesium myristate, barium stearate, aluminum stearate, copper stearate, etc. Among these, zinc stearate is preferable. These are commercially available or can be easily synthesized from the corresponding carboxylic acid.
These alkylcarboxylic acid polyvalent metal salts are preferably used in an amount of 0.1 to 50 parts by mass, and 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin (binder resin) of the heat-resistant slip layer. Is more preferable.

  The amount of additives other than these talc and alkylcarboxylic acid polyvalent metal salt contained in the heat-resistant slip layer varies, but is preferably 0.001 to 50% by weight based on the total amount of the heat-resistant slip layer. 0.01% by mass to 20% by mass is more preferable.

Some ester surfactants have acid radicals, and when the amount of heat from the thermal head increases, the ester decomposes, and the pH of the back layer decreases, which may cause severe corrosion wear on the thermal head. is there. For this, there are a method using a neutralized ester surfactant, a method using a neutralizing agent such as magnesium hydroxide, and the like.
Examples of other additives include higher fatty acid alcohols, organopolysiloxanes, and organic carboxylic acids.

Although the heat-resistant slipping layer contains a resin, a known resin having high heat resistance can be used. Examples include cellulose resins such as ethyl cellulose, hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, nitrocellulose, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl acetoacetal Resin, vinyl chloride-vinyl acetate copolymer, vinyl resin such as polyvinylpyrrolidone, polymethyl methacrylate, polyethyl acrylate, polyacrylamide, acrylic resin such as acrylonitrile-styrene copolymer, polyamide resin, polyimide resin, Polyamideimide resin, polyvinyltoluene resin, coumarone indene resin, polyester resin, polyurethane resin, polyether resin, polybuta Ene resin, polycarbonate resin, chlorinated polyolefin resin, fluorine resin, epoxy resin, phenol resin, silicone resin, and a single or a mixture of natural or synthetic resins such as silicone-modified or fluorine-modified urethane.
In order to enhance heat resistance, the resin can be crosslinked by irradiation with ultraviolet rays or electron beams. It is also possible to crosslink by heating using a crosslinking agent. At this time, a catalyst may be added. Examples of the crosslinking agent include isocyanate (polyisocyanate, cyclic trimer of polyisocyanate, etc.), metal (titanium tetrabutyrate, zirconium tetrabutyrate, aluminum triisopropylate, etc.) and the like. Examples of the resin to be reacted with these crosslinking agents include polyvinyl acetal, polyvinyl butyral, polyester polyol, alkyd polyol, and a silicone compound containing an amino group in the side chain.

It is known that the reaction with the crosslinking agent is promoted by placing the heat-resistant slipping layer in a high temperature and high humidity environment after coating. In this regard, in the present invention, it is preferable to select a condition in which the phosphate ester represented by the general formula (1) contained in the heat resistant slipping layer or the salt localized structure of the phosphate ester is not destroyed. Moreover, the combination of the said resin and a crosslinking agent can be selected so that a crosslinking reaction can fully be accelerated | stimulated on the conditions in which the said phosphate ester or salt localized structure in the heat-resistant slipping layer of this invention is not destroyed. A combination of a resin and a cross-linking agent that can sufficiently promote the cross-linking reaction within one day under a low humidity condition of 60 ° C. is preferable.
Such a resin is preferably one having two or more hydroxyl groups in the polymer chain length terminal or polymer structure of the resin. Here, the term “having two or more hydroxyl groups in the polymer chain length terminal or polymer structure of the resin” means that two or more hydroxyl groups are present in the polymer chain length terminal of the resin or in the structure that is not the polymer terminal. It means having. Examples of such a resin include polyacryl polyol, polyester polyol, polyether polyol, and the like. In the present invention, the polyacryl polyol includes polymethacryl polyol. In the present invention, among these, a polyacryl polyol is preferable.
As the resin having two or more hydroxyl groups in the polymer chain length terminal or polymer structure of the resin, commercially available resins can be used, for example, Takelac (registered trademark) series manufactured by Mitsui Chemicals Polyurethane Co., Ltd., Soken Chemical Thermolac series manufactured by Hitachi Chemical Co., Ltd., Hitachioid Co., Ltd., Harima Chemical Co., Ltd. Hariakuron series, Dainippon Ink Co., Ltd. Acrydic series, and Nippon Polyurethane Co., Ltd. NIPPON series Product name), but is not limited thereto.

  The hydroxyl value of a resin having two or more hydroxyl groups in the polymer chain length terminal or polymer structure of the resin is preferably 5 to 300, and most preferably 15 to 100, based on the solid content of the resin. The hydroxyl value is the number of mg of potassium hydroxide equivalent to the hydroxyl group in 1 g of a sample specified in JIS K-1557-1. The acid value of such a resin is preferably 20 or less, most preferably 0 to 10 based on the solid content of the resin. The acid value is the number of mg of potassium hydroxide required to neutralize the free acid in 1 g of a sample specified by JIS K-1557-5.

When cross-linking using an isocyanate-based cross-linking agent, the progress of the cross-linking reaction can be detected by detecting residual isocyanate groups by IR spectrum measurement. The IR spectrum peak intensity derived from the residual isocyanate group after the crosslinking reaction is 20% or less with respect to the IR spectrum peak intensity derived from the residual isocyanate group in the heat resistant slipping layer, preferably 10% or less, most preferably Is 5% or less.
In order to efficiently exhibit the effects of the present invention, the temperature for promoting the reaction between the resin and the crosslinking agent is preferably 65 ° C. or less, more preferably 55 ° C. or less, and 40 ° C. to 53 ° C. Most preferably it is. The time for promoting the reaction between the resin and the crosslinking agent is preferably 12 hours or more and 40 days or less, more preferably 18 hours or more and 30 days or less, and most preferably 1 day or more and 20 days or less. preferable.

  The heat resistant slipping layer is formed by coating the above-described coating solution by a known method such as gravure coating, roll coating, blade coating, or wire bar. The film thickness of the heat resistant slipping layer is preferably 0.1 to 3 μm, and more preferably 0.2 to 2 μm.

(Base film)
The base film of the heat-sensitive transfer sheet of the present invention is not particularly limited, and any conventionally known film can be used as long as it has required heat resistance and strength. Examples include thin papers such as glassine paper, condenser paper, puffin paper, polyesters having high heat resistance such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polyether sulfone, polypropylene, polycarbonate, Specific examples of base film that is preferably a stretched or unstretched film of plastic such as cellulose acetate, polyethylene derivative, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polymethylpentene, ionomer, or a laminate of these materials Take an example. Among these, the polyester film is particularly preferable, a stretched polyester film is more preferable, and a polyester film formed by stretching after forming an easy-adhesion layer on at least one surface of the base film is particularly preferable.
The thickness of the base film is appropriately selected depending on the material so that the strength, heat resistance and the like are appropriate, but those having a thickness of about 1 to 30 μm are preferably used. More preferably, it is about 1-20 micrometers, More preferably, about 3-10 micrometers is used.

(Easy adhesion treatment)
The base film may be subjected to easy adhesion treatment for the purpose of improving the wettability and adhesiveness of the coating solution. As an easy adhesion treatment method, known resins such as corona discharge treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, surface roughening treatment, chemical treatment, vacuum plasma treatment, atmospheric pressure plasma treatment, primer treatment, grafting treatment, etc. Surface modification techniques can be exemplified.
Among these, an easily bonding layer can also be formed on a base film by application | coating, and it is preferable to form an easily bonding layer in this invention. Examples of the resin used for the easy-adhesion layer include polyester resins, polyacrylate resins, polyvinyl acetate resins, vinyl resins such as polyvinyl chloride resins and polyvinyl alcohol resins, and polyvinyl resins such as polyvinyl acetoacetal and polyvinyl butyral. Examples include acetal resins, polyether resins, polyurethane resins, styrene acrylate resins, polyacrylamide resins, polyamide resins, polystyrene resins, polyethylene resins, polypropylene resins, and polyvinylpyrrolidone resins. .
The base film used for the support can be formed by subjecting an unstretched film to a coating treatment and then a stretching treatment when the film is formed by melt extrusion.
In addition, two or more kinds of the above treatments can be used in combination.
Here, as described above, in the present invention, a stretched film is preferably formed after an easy-adhesion layer is formed on at least one surface of the base film. In the heat-sensitive transfer sheet of the present invention, it is preferable to provide an easy adhesion layer (dye barrier layer) between the dye layer and the substrate film.

  A dye layer containing a dye for transfer (preferably a sublimation dye) can be formed by applying a dye layer coating solution.

(Dye layer)
In the dye layer of the present invention, it is preferable that a dye layer of each color of yellow, magenta, and cyan and, if necessary, a black dye layer are repeatedly coated on the same base film in the order of a plane. As an example, the yellow, magenta, and cyan hue dye layers are applied in the major axis direction on the same base film in a surface sequential manner corresponding to the recording surface area of the thermal transfer image-receiving sheet. Can be mentioned. In addition to these three layers, it is also preferable that either a black dye layer or a transferable protective layer (this may be a transferable protective layer laminate described later) or both are separately applied. It is.
When taking such an aspect, it is also a preferable aspect to provide a mark on the thermal transfer sheet for the purpose of transmitting the starting point of each color to the printer. Thus, by repeatedly painting in the surface order, it is possible to form an image by transferring a dye, and further to laminate a protective layer on the image with a single thermal transfer sheet.
However, the present invention is not limited to the method of providing the dye layer as described above. A sublimation type thermal transfer ink layer and a heat melting transfer ink layer can be provided side by side, and it is also possible to change such as providing a dye layer of a hue other than yellow, magenta, cyan and black. Moreover, the form may be long, a single-wafer thermal transfer sheet, or may be preferably used in an embodiment in which the thermal transfer sheets before use are stored in an overlapped state.

(Dye layer coating solution)
The dye layer coating solution contains at least a sublimable dye and a binder resin, and if necessary, contains organic fine powder or inorganic fine powder, waxes, silicone resin, fluorine-containing organic compound and the like. This is also a preferred embodiment of the present invention.

In the heat-sensitive transfer sheet of the present invention, each dye is preferably contained in the dye layer in an amount of 20 to 80% by mass, and more preferably 30 to 70% by mass.
The dye layer is applied by a general method such as roll coating, bar coating, gravure coating, or gravure reverse coating. The coating amount of the dye layer is preferably 0.1 to 2.0 g / m ² (in terms of solid content, hereinafter the coating amount in the present invention is a numerical value in terms of solid content unless otherwise specified), and more preferably. Is 0.2 to 1.2 g / m ² . The film thickness of the dye layer is preferably from 0.1 to 2.0 μm, more preferably from 0.2 to 1.2 μm.

  The dye layer may have a single layer structure or a multilayer structure. In the case of a multilayer structure, the composition of each layer constituting the dye layer may be the same or different.

(dye)
The dye used in the present invention is not particularly limited as long as it is diffused by heat, can be incorporated into the thermal transfer sheet, and can be transferred from the thermal transfer sheet to the thermal transfer image-receiving sheet by heating. A conventionally used dye or a known dye can be used.
Preferred dyes include, for example, methine series such as diarylmethane series, triarylmethane series, thiazole series, and merocyanine, indoaniline, acetophenone azomethine, pyrazoloazomethine, imidazole azomethine, imidazoazomethine, and azomethine series represented by pyridone azomethine. Cyanomethylene, thiazine, azine, acridine, benzeneazo, pyridoneazo, thiophenazo, isothiazoleazo, pyrroleazo, pyralazo, imidazoleazo, thiadiazole, typified by xanthene, oxazine, dicyanostyrene, tricyanostyrene Azos such as azo, triazole azo, and dizazo, spiropyrans, indolinospiropyrans, fluorans, rhodamine lactams, naphthoquinones, anthrax Down system, quinophthalone, and the like.

  Specific examples include yellow disperse yellow 231, disperse yellow 201, solvent yellow 93, and magenta dyes such as disperse violet 26, disperse thread 60, solvent red 19 and the like, and cyan. Examples of the dye include, but are not limited to, Solvent Blue 63, Solvent Blue 36, Disperse Blue 354, Disperse Blue 35, and the like. It is also possible to arbitrarily combine the dyes of the above-mentioned hues.

(Resin for dye layer)
In the heat-sensitive transfer sheet of the present invention, the dye is usually coated on the substrate film in a state of being dispersed in a polymer compound called a resin (also called a binder or a resin binder). In this invention, a well-known thing can be used as a resin binder contained in a dye layer. Examples include acrylic resins such as polyacrylonitrile, polyacrylic acid esters and polyacrylamide, polyvinyl acetal resins such as polyvinyl acetoacetal and polyvinyl butyral, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose Cellulose acetate resins such as cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose nitrate, etc. Cellulose resins such as nitrocellulose, ethylhydroxyethylcellulose and ethylcellulose, polyurethane resins, polyamide resins, polyester resins, polycarbonate resins, phenoxy resins , Phenolic resin, epoxy resin, various elastomers, etc. The recited dye layer by at least one resin selected from the group consisting of the above is configured.
In addition to using these alone, they can be mixed or copolymerized, and can be crosslinked with various crosslinking agents.
In the present invention, cellulose resins and polyvinyl acetal resins are preferable, and polyvinyl acetal resins are more preferable. Among them, polyvinyl acetoacetal resin and polyvinyl butyral resin are preferably used in the present invention.
The ratio (mass ratio) of the content of the dye in the dye layer may be any ratio, but is preferably 0.1 to 5.0, more preferably 0.5 to 3.0, and 9-2.0 is more preferable.

(Transferable protective layer laminate)
In the present invention, it is also preferable to provide the heat-sensitive transfer sheet with the transferable protective layer laminate in the surface order. The transferable protective layer laminate is for forming a protective layer made of a transparent resin on the heat-transferred image by thermal transfer to cover and protect the image, and has durability such as scratch resistance, light resistance, and weather resistance. The purpose is to improve performance. This is effective when image durability such as light resistance, scratch resistance and chemical resistance is insufficient if the transferred dye is exposed to the surface of the image receiving sheet.
The transferable protective layer laminate can be formed on the base film in the order of the release layer, the protective layer, and the adhesive layer from the base film side. It is also possible to form the protective layer with a plurality of layers. When the protective layer has the functions of other layers, the release layer and the adhesive layer can be omitted. As the base film, a film provided with an easy-adhesion layer can also be used.

(Transferable protective layer)
The resin forming the transferable protective layer of the present invention is preferably a resin excellent in scratch resistance, chemical resistance, transparency and hardness, such as polyester resin, acrylic resin, polystyrene resin, polyurethane resin, acrylic urethane resin, and these Silicone-modified resins, ultraviolet blocking resins, mixtures of these resins, ionizing radiation curable resins, ultraviolet curable resins, and the like can be used. Of these, polyester resins and acrylic resins are preferable.
It is also possible to crosslink with various crosslinking agents.

(Transferable protective layer resin)
The acrylic resin is a polymer composed of at least one monomer selected from conventionally known acrylate monomers and methacrylate monomers, and may be copolymerized with styrene, acrylonitrile or the like in addition to the acrylic monomer. As a preferred monomer, methyl methacrylate is charged and contained in an amount of 50% by mass or more.
The acrylic resin of the present invention preferably has a molecular weight of 20,000 or more and 100,000 or less.

  As the polyester resin of the present invention, conventionally known saturated polyester resins can be used. When the polyester resin is used, the glass transition temperature is preferably 50 to 120 ° C., the molecular weight is preferably in the range of 2,000 to 40,000, and further in the range of 4,000 to 20,000. Sometimes the foil breakability is improved, which is more preferable.

(UV absorber)
In the present invention, the protective layer and / or the adhesive layer preferably contains an ultraviolet absorber. As the ultraviolet absorber, conventionally known inorganic ultraviolet absorbers and organic ultraviolet absorbers can be used. Examples of organic UV absorbers include salicylate-based, benzophenone-based, benzotriazole-based, triazine-based, substituted acrylonitrile-based, hindered amine-based non-reactive UV absorbers, and non-reactive UV absorbers such as, for example, Introducing an addition polymerizable double bond such as vinyl group, acryloyl group or methacryloyl group, or alcoholic hydroxyl group, amino group, carboxyl group, epoxy group, isocyanate group, etc. A polymerized or grafted product can be used. In addition, a method is disclosed in which a UV absorber is dissolved in a resin monomer or oligomer and then the monomer or oligomer is polymerized (Japanese Patent Application Laid-Open No. 2006-21333), and thus obtained UV blocking resin is used. You can also In this case, the ultraviolet absorber may be non-reactive.
Among these ultraviolet absorbers, benzophenone, benzotriazole, and triazine are particularly preferable. These UV absorbers are preferably used in combination so as to cover the effective UV absorption wavelength range according to the characteristics of the dye used for image formation. In the case of non-reactive UV absorbers, UV absorbers are used. It is preferable to use a mixture of a plurality of different structures so that the agent does not precipitate.
Commercially available UV absorbers include Tinuvin-P (manufactured by Ciba Geigy), JF-77 (manufactured by Johoku Chemical), Sea Soap 701 (manufactured by Shiraishi Calcium), Sumisop 200 (manufactured by Sumitomo Chemical), and Biosoap 520 (manufactured by Kyodo Yakuhin). , ADK STAB LA-32 (manufactured by Asahi Denka) (all are trade names) and the like.

(Formation of transferable protective layer)
Although the formation method of a protective layer is dependent on the kind of resin used, it can form by the method similar to the formation method of the said dye layer, and the thickness of 0.5-10 micrometers is preferable.

(Release layer)
In the case where the transferable protective layer is difficult to peel from the base film during thermal transfer, a release layer can be formed between the base film and the protective layer. A release layer may be further formed between the transferable protective layer and the release layer. The release layer includes, for example, waxes, silicone wax, silicone resin, fluororesin, acrylic resin, polyvinyl alcohol resin, cellulose derivative resin, urethane resin, acetic acid vinyl resin, acrylic vinyl ether resin, maleic anhydride resin, and A coating liquid containing at least one copolymer of these resin groups can be formed by coating and drying by a conventionally known method such as gravure coating or gravure reverse coating. Among the above-mentioned resins, the acrylic resin is preferably a simple substance such as acrylic acid or methacrylic acid, or a resin copolymerized with another monomer, or a cellulose derivative resin. Excellent in releasability.
It is also possible to crosslink with various crosslinking agents, and ionizing radiation curable resins and ultraviolet curable resins can also be used.

  The release layer can be appropriately selected from those that transfer to the transfer medium during thermal transfer, those that remain on the substrate film side, or those that coagulate and break down. However, the release layer is on the substrate film side by thermal transfer. It is excellent in terms of surface glossiness, transfer stability of the protective layer, etc., so that the interface between the release layer and the transferable protective layer becomes the surface of the protective layer after thermal transfer. This is a preferred embodiment. The release layer can be formed by a conventionally known coating method, and the thickness is preferably about 0.5 to 5 μm in a dry state.

(Adhesive layer)
As the uppermost layer of the transferable protective layer laminate, an adhesive layer can be provided on the outermost surface of the protective layer. As a result, the adhesion of the protective layer to the transfer target can be improved.

2) Thermal transfer image-receiving sheet Next, a thermal transfer image-receiving sheet (hereinafter also simply referred to as an image-receiving sheet) that can be used in combination with the thermal transfer sheet of the present invention to form a thermal transfer print will be described in detail. The thermal transfer image-receiving sheet has at least one receiving layer containing a thermoplastic receiving polymer for receiving a dye on a support. The receiving layer can contain an ultraviolet absorber, a release agent, a lubricant, an antioxidant, an antiseptic, a surfactant, and other additives. Between the support and the receiving layer, for example, an intermediate layer such as a heat insulating layer (porous layer), a gloss control layer, a white background adjustment layer, a charge control layer, an adhesive layer, a primer layer, etc. may be formed. It is preferable to have at least one heat insulating layer between the support and the receiving layer.
The receptor layer and these intermediate layers are preferably formed by simultaneous multilayer coating, and a plurality of intermediate layers can be provided as necessary.
A curl adjustment layer, a writing layer, and a charge adjustment layer may be formed on the back side of the support. In order to apply each layer on the back surface of the support, general methods such as roll coating, bar coating, gravure coating, and gravure reverse coating can be used.
In the present invention, in particular, what has a heat insulating layer containing a hollow polymer (particle) latex and a receiving layer containing a polymer (particle) latex on the support effectively exhibits the effects of the present invention. preferable.

  The heat-sensitive transfer image-receiving sheet preferably uses a polymer latex capable of being dye-dyed on the receiving layer. The polymer latex may be used alone or in combination with a plurality of polymer latexes.

The polymer latex is generally a thermoplastic resin dispersed as fine particles in a water-soluble dispersion medium. Examples of the thermoplastic resin used in the polymer latex of the present invention include polycarbonate, polyester, polyacrylate, vinyl chloride copolymer, polyurethane, styrene-acrylonitrile copolymer, polycaprolactone, and the like.
Of these, polycarbonate, polyester and vinyl chloride copolymer are preferable, and polyester and vinyl chloride copolymer are particularly preferable.

  The polyester is obtained by condensation of a dicarboxylic acid derivative and a diol compound, may contain an aromatic ring or a saturated carbon ring, and may contain a water-soluble group for imparting dispersibility.

As vinyl chloride copolymer, vinyl chloride and vinyl acetate copolymer, vinyl chloride and acrylate copolymer, vinyl chloride and methacrylate copolymer, vinyl chloride, vinyl acetate and acrylate copolymer, vinyl chloride and Examples thereof include a copolymer of acrylate and ethylene. Thus, the copolymer may be a binary copolymer or a ternary or higher copolymer, and the monomers may be distributed irregularly or may be block copolymerized.
An auxiliary monomer component such as a vinyl alcohol derivative, a maleic acid derivative, or a vinyl ether derivative may be added to the copolymer. In the copolymer, the vinyl chloride component is preferably contained in an amount of 50% by mass or more, and auxiliary monomer components such as maleic acid derivatives and vinyl ether derivatives are preferably 10% by mass or less.
The polymer latex may be used alone or as a mixture. The polymer latex may have a uniform structure or a core / shell type, and at this time, the glass transition temperatures of resins forming the core and the shell may be different.

  The glass transition temperature (Tg) of such a polymer latex is preferably 20 ° C. or higher and 90 ° C. or lower, more preferably 25 ° C. or higher and 80 ° C. or lower.

Examples of commercially available acrylate latex include Nipol LX814 (Tg25 ° C.), NipolLX857X2 (Tg 43 ° C.), etc. (all trade names) manufactured by Nippon Zeon Co., Ltd.
Commercially available polyester latexes include Toyobo Co., Ltd., Vironal MD-1100 (Tg 40 ° C.), Vironal MD-1400 (Tg 20 ° C.), Vironal MD-1480 (Tg 20 ° C.), MD-1985 (Tg 20 ° C.), etc. (Both are product names).
Commercially available vinyl chloride copolymers include Nivin Chemical Industry Co., Ltd., Vinibrand 276 (Tg 33 ° C.), Vini Blanc 609 (Tg 48 ° C.), Sumika Chemtex Co., Ltd. Sumilite 1320 (Tg 30 ° C.), Sumi Elite 1210 (Tg 20 ° C.) and the like (both are trade names).

  The amount of the polymer latex added is preferably 50 to 98% by mass, more preferably 70 to 95% by mass, based on the total polymer content in the receptor layer. The average particle size of the polymer latex is preferably 1 to 50000 nm, more preferably 5 to 1000 nm.

The heat-sensitive transfer image-receiving sheet that can be used in the present invention preferably contains a hollow polymer in the heat insulating layer.
In the present invention, the hollow polymer is a polymer particle having voids inside the particle, preferably an aqueous dispersion. For example, 1) water or the like inside the partition formed by polystyrene, acrylic resin, styrene-acrylic resin or the like. Contains dispersion medium. After coating and drying, non-foamed hollow polymer particles in which water inside the particles evaporates outside the particles and the inside of the particles becomes hollow. 2) Low boiling liquids such as butane and pentane are polychlorinated. It is covered with a resin made of vinylidene, polyacrylonitrile, polyacrylic acid, polyacrylic acid ester, or a mixture or polymer thereof. After coating, the inside of the particles expands due to expansion of the low-boiling liquid by heating. Hollow microbubbles that become hollow 3) Microballoons obtained by heating and foaming the above 2) in advance to form hollow polymers And the like.
Among these, the non-foamed hollow polymer particles of 1) above are preferable, and two or more kinds can be mixed and used as necessary. Specific examples include Ropeke HP-1055 manufactured by Rohm and Haas, SX866 (B) manufactured by JSR, Nipol MH5055 manufactured by Nippon Zeon (all are trade names), and the like.

  The average particle diameter of these hollow polymers is preferably 0.1 to 5.0 μm, more preferably 0.2 to 3.0 μm, and particularly preferably 0.4 to 1.4 μm. The hollow polymer preferably has a porosity of 20 to 70%, more preferably 30 to 60%.

  The size of the hollow polymer particles is calculated by measuring the equivalent-circle diameter of the outer diameter using a transmission electron microscope. The average particle diameter is obtained by observing at least 300 hollow polymer particles using a transmission electron microscope, calculating the circle equivalent diameter of the outer shape, and averaging. The void ratio of the hollow polymer is determined from the ratio of the volume of the void portion to the particle volume.

  As the polymer characteristics of the hollow polymer, the glass transition temperature (Tg) is preferably 70 ° C. or higher and 200 ° C. or lower, more preferably 90 ° C. or higher and 180 ° C. or lower. As the hollow polymer, hollow polymer latex is particularly preferable.

  A water-soluble polymer can be contained in the receiving layer and / or the heat insulating layer of the heat-sensitive transfer image-receiving sheet. Here, the water-soluble polymer has a solubility of 0.05 g or more with respect to 100 g of water at 20 ° C., more preferably 0.1 g or more, and still more preferably 0.5 g or more.

  Examples of water-soluble polymers that can be used in the thermal transfer image-receiving sheet include carrageenans, pectin, dextrin, gelatin, casein, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, polyvinylpyrrolidone copolymer, polyvinyl alcohol, polyethylene glycol, Examples thereof include polypropylene glycol and water-soluble polyester. Of these, gelatin and polyvinyl alcohol are preferred.

Gelatin having a molecular weight of 10,000 to 1,000,000 can be used, and gelatin may contain anions such as Cl ⁻ and SO ₄ ²⁻ , Fe ²⁺ , Ca ²⁺ , Mg ^It may contain cations such as ²⁺ , Sn ²⁺ and Zn ²⁺ . It is preferable to add gelatin dissolved in water.
Moreover, well-known crosslinking agents, such as an aldehyde type crosslinking agent, an N-methylol type crosslinking agent, a vinyl sulfone type crosslinking agent, a chlorotriazine type crosslinking agent, can be added to gelatin. Of these, vinyl sulfone type crosslinking agents and chlorotriazine type crosslinking agents are preferred. Specific examples include bisvinylsulfonylmethyl ether, N, N′-ethylene-bis (vinylsulfonylacetamide) ethane, and 4,6-dichloro. -2-Hydroxy-1,3,5-triazine or its sodium salt.

  As the polyvinyl alcohol, various polyvinyl alcohols such as a completely saponified product, a partially saponified product, and a modified polyvinyl alcohol can be used. As for these polyvinyl alcohols, those described in Koichi Nagano et al., “Poval” (published by Kobunshi Shuppankai) are used. Polyvinyl alcohol can be adjusted in viscosity or stabilized by a trace amount of solvent or inorganic salt added to the aqueous solution. Specifically, the polyvinyl alcohol described in pages 144 to 154 can be used. it can. As a typical example, it is possible to improve the coating surface quality by containing boric acid, which is preferable. The amount of boric acid added is preferably 0.01 to 40% by mass relative to polyvinyl alcohol.

  Specific examples of polyvinyl alcohol include PVA-105, PVA-110, PVA-117, and PVA-117H as fully saponified products, and PVA-203, PVA-205, PVA-210, and PVA-220 as partially saponified products. Examples of the modified polyvinyl alcohol include C-118, HL-12E, KL-118, and MP-203. (All are trade names, manufactured by Kuraray Co., Ltd.)

  The receiving layer of the heat-sensitive transfer image-receiving sheet can contain a polymer compound having an aliphatic group substituted with a fluorine atom in the side chain. In this case, the thermal transfer sheet may contain the same polymer compound as the polymer compound having an aliphatic group substituted in the side chain with a fluorine atom substituted, or may contain a different polymer compound in the same category, This is a preferred embodiment. Moreover, you may contain solid waxes, such as well-known polyethylene wax and amide wax, silicone oil, a phosphoric ester compound, a fluorine-type surfactant, and a silicone-type surfactant as a mold release agent.

  The content of the polymer compound having an aliphatic group substituted with a fluorine atom in the side chain is 0.01% to 20%, preferably 0.1% to the total solid content (mass) of the receiving layer. 10%, more preferably 1% to 5%.

3) Image Forming Method Next, an image forming method that can be performed using the heat-sensitive transfer sheet of the present invention will be described.
In the image forming method, the receiving layer of the thermal transfer image-receiving sheet and the dye layer of the thermal transfer sheet are overlapped so that the thermal energy corresponding to the image signal from the thermal head is applied from the heat-resistant slipping layer side of the thermal transfer sheet. By doing so, an image is formed.
Specific image formation can be performed in the same manner as described in, for example, JP-A-2005-88545. In the present invention, the printing time is preferably less than 15 seconds, more preferably 3 to 12 seconds, and even more preferably 3 to 7 seconds from the viewpoint of shortening the time until the printed matter is provided to the consumer.

  In order to satisfy the printing time, the line speed during printing is preferably 0.73 msec / line or less, more preferably 0.65 msec / line or less. Further, from the viewpoint of improving transfer efficiency under high speed conditions, the maximum temperature reached by the thermal head during printing is preferably 180 ° C. or higher and 450 ° C. or lower, more preferably 200 ° C. or higher and 450 ° C. or lower. Furthermore, 350 degreeC or more and 450 degrees C or less are preferable.

The present invention can be used in printers, copiers and the like using a thermal transfer recording system. As the means for applying thermal energy at the time of thermal transfer, any conventionally known means for applying can be used. For example, recording is performed by a recording device such as a thermal printer (for example, product name, video printer VY-100, manufactured by Hitachi, Ltd.). By controlling the time, the intended purpose can be sufficiently achieved by applying thermal energy of about 5 to 100 mJ / mm ² . The thermal transfer image-receiving sheet used in combination with the thermal transfer sheet of the present invention is a sheet- or roll-shaped thermal transfer image-receiving sheet capable of thermal transfer recording, cards, and transmission-type manuscript preparation by appropriately selecting a support. It can also be applied to various uses such as a sheet for use.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these. In Examples, “part” or “%” is based on mass unless otherwise specified.

Example 1
(Preparation of thermal transfer sheet)
The solid coating amount after drying is 1 g / m ² on the surface opposite to the easy-adhesion layer of a 4.5 μm thick polyester film produced by stretching after an easy-adhesion layer is formed on one side as a base film. Then, a heat resistant slipping layer coating solution described later was applied. The ratio of reactive groups (-NCO / OH) between the polyisocyanate and the resin in the heat resistant slipping layer coating solution described later was 1.1. Immediately after the coating, it was dried in an oven at 100 ° C. for 1 minute and subsequently subjected to a heat treatment (60 ° C. for 18 hours) to carry out a crosslinking reaction between the isocyanate and the polyol to be cured. After the heat treatment, unreacted isocyanate groups were confirmed by IR measurement to confirm that they were sufficiently reacted.
The yellow, magenta, and cyan dye layers and the transferable protective layer laminate are arranged in a plane order on the easy-adhesion layer coating side of the heat-resistant slip layer-formed polyester film produced in this manner, using a coating liquid described later. An applied thermal transfer sheet was prepared. The solid content coating amount of each dye layer was 0.8 g / m ² . Immediately after applying these, they were dried in a 100 ° C. oven for 1 minute.
In addition, the transferable protective layer laminate is formed by applying a release layer coating solution, applying a protective layer coating solution thereon, drying, and further applying an adhesive layer coating solution thereon. Applied.

Dispersion for heat-resistant slipping layer Polyacryl polyol resin (50% solution) 50.0 parts by mass (hydroxyl value is 61, acid value is 5 with respect to resin solids)
Tris (m-cresyl) phosphate (melting point: 26 ° C.) 3.5 parts by mass Zinc stearate (zinc salt of carboxylic acid having 18 carbon atoms) 0.5 parts by mass Talc 2.0 parts by mass Magnesium oxide 0.5 parts by mass Methyl ethyl ketone / toluene mixed solvent 43.5 parts by mass

The resin and solvent of the dispersion for the heat-resistant slipping layer were dissolved in advance, and other additives were added to the solution for premixing, followed by dispersion. The dispersion condition was carried out under one of the following three conditions.
(Condition 1) Disperse for 180 minutes using a paint shaker (Condition 2) Disperse planetary ball mill P-7 (trade name) manufactured by Fritsch, Germany at 500 rpm for 40 minutes (Condition 3) Planetary ball mill manufactured by Fritsch, Germany Dispersed with P-7 type at 500 rpm for 20 minutes, followed by 100 rpm for 20 minutes

Heat-resistant slip layer coating solution Heat-resistant slip layer dispersion 67.8 parts by weight Polyisocyanate (75% solution) 11.2 parts by weight (Bernock D-750, trade name, manufactured by Dainippon Ink & Chemicals, Inc.)
Methyl ethyl ketone / toluene mixed solvent 21.0 parts by mass

Yellow Dye Layer Coating Liquid Dye Compound (Y-1) 1.0 part by weight Dye Compound (Y-2) 6.1 part by weight Dye Compound (Y-3) 0.8 part by weight Polyvinyl acetal resin 6.9 parts by weight (Denka Butyral # 5000-D, trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.)
0.1 parts by mass of fluorine-containing polymer compound (Megafac F-472SF, trade name, manufactured by Dainippon Ink & Chemicals, Inc.)
Matting agent (Flusen UF, trade name, manufactured by Sumitomo Seiko Co., Ltd.) 0.12 parts by mass Methyl ethyl ketone / toluene mixed solvent 85 parts by mass

Magenta dye layer coating solution Dye compound (M-1) 0.8 part by weight Dye compound (M-2) 1.0 part by weight Dye compound (M-3) 6.8 parts by weight Polyvinyl acetal resin 6.2 parts by weight (ESREC KS-1, trade name, manufactured by Sekisui Chemical Co., Ltd.)
Release agent 0.05 parts by mass (X-22-3000T, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Mold release agent 0.03 parts by mass (TSF4701, trade name, manufactured by Momentive Performance Materials Japan GK)
Matting agent 0.15 parts by mass (Flosen UF, trade name, manufactured by Sumitomo Seiko Co., Ltd.)
85 parts by mass of methyl ethyl ketone / toluene mixed solvent

Cyan dye layer coating solution Dye compound (C-1) 0.4 parts by weight Dye compound (C-2) 8.9 parts by weight Dye compound (C-3) 0.5 parts by weight Polyvinyl acetal resin 5.0 parts by weight (Denka Butyral # 5000-D, trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.)
0.1 parts by mass of fluorine-containing polymer compound (Megafac F-472SF, trade name, manufactured by Dainippon Ink & Chemicals, Inc.)
Matting agent (Flusen UF, trade name, manufactured by Sumitomo Seiko Co., Ltd.) 0.12 parts by mass Methyl ethyl ketone / toluene mixed solvent 85 parts by mass

(Transferable protective layer laminate)
A release layer, a protective layer, and an adhesive layer coating solution having the following composition were applied to the same polyester film as that used for the preparation of the dye layer to form a transferable protective layer laminate. The coating amount of the releasing layer 0.2 g / ^{m 2} when dry film, the protective layer 0.4 g / ^{m 2,} and an adhesive layer 2.0 g / ^{m 2.}

Release layer coating solution Modified cellulose resin 5.0 parts by mass (L-30, trade name, Daicel Chemical)
Methyl ethyl ketone / toluene mixed solvent 95.0 parts by mass Protective layer coating solution Acrylic resin solution (solid content 40%) 90 parts by mass (UNO-1, trade name, manufactured by Gifu Ceramics Co., Ltd.)
Methanol / isopropanol mixed solvent 10 parts by mass Adhesive layer coating solution Acrylic resin 25 parts by mass (Dianaal BR-77, trade name, manufactured by Mitsubishi Rayon Co., Ltd.)
The following ultraviolet absorbent UV-1 0.5 part by mass The following ultraviolet absorbent UV-2 2 part by mass The following ultraviolet absorbent UV-3 0.5 part by mass The following ultraviolet absorbent UV-4 0.5 part by mass PMMA fine particles (poly Methyl methacrylate fine particles) 0.4 parts by mass Methyl ethyl ketone / toluene mixed solvent 70 parts by mass

(Preparation of thermal transfer image-receiving sheet)
The paper support surface laminated on both sides with polyethylene was subjected to corona discharge treatment, and then a gelatin subbing layer containing sodium dodecylbenzenesulfonate was provided. On this, an undercoat layer, a heat insulating layer, a receiving layer lower layer, and a receiving layer upper layer having the following composition are laminated in this order from the support side in FIG. 9 in US Pat. No. 2,761,791. The simultaneous multilayer coating was carried out by the method exemplified in 1. The coating amount at the time of drying is undercoat layer: 6.2 g / m ² , heat insulation layer: 8.0 g / m ² , receiving layer lower layer: 2.8 g / m ² , receiving layer upper layer: 2.3 g / m ² Application was performed so that Moreover, the following composition represents the mass part as solid content.

Receptor layer upper layer 20.0 parts by mass of vinyl chloride latex (Viniblanc 900, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
2.6 parts by weight of vinyl chloride latex (Viniblanc 276, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
Gelatin (10% aqueous solution) 2.3 parts by mass The following ester wax EW-1 2.0 parts by mass The following surfactant F-1 0.09 parts by mass The following surfactant F-2 0.36 parts by mass Receiving layer lower layer 13.0 parts by weight of vinyl chloride latex (Viniblanc 690, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
13.0 parts by mass of vinyl chloride latex (Viniblanc 900, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
Gelatin (10% aqueous solution) 8.0 parts by mass The following surfactant F-1 0.04 parts by mass Thermal insulation layer Hollow polymer particle latex 66.0 parts by mass (MH5055, trade name, manufactured by Nippon Zeon Co., Ltd.)
Gelatin (10% aqueous solution) 24.0 parts by mass Undercoat layer Polyvinyl alcohol 7.0 parts by mass (Poval PVA205, trade name, manufactured by Kuraray Co., Ltd.)
Styrene butadiene rubber latex 55.0 parts by mass (SN-307, trade name, manufactured by Nippon A & L Co., Ltd.)
0.03 part by mass of the following surfactant F-1

Except for changing the type of the phosphate ester in the heat resistant slipping layer from the thermal transfer sheet (101) to (103) to the compound represented by the general formula (1) defined in the present invention as follows. Similarly, (109) was prepared from the thermal transfer sheets (104).
Thermal transfer sheets (104) to (106) used Phoslex A-18 (melting point: 62 ° C. in a mixture of mono- and di-stearyl phosphate esters) manufactured by Sakai Chemical Industry Co., Ltd. as a phosphate ester.
Thermal transfer sheets (107) to (109) used Prisurf A208N manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (melting point: −2 ° C. in a mono- and di-polyoxyalkylene alkyl ether phosphate ester mixture) as the phosphate ester. . In addition, melting | fusing point of these phosphate ester is the value calculated | required by the differential scanning calorimeter (DSC) measurement.

(Characteristic X-ray intensity measurement and calculation)
An electron beam was irradiated from the heat-resistant slipping layer side of the heat-sensitive transfer sheet (101), and the characteristic X-ray intensity derived from the K-line of the phosphorus element in the heat-resistant slipping layer was measured. Specifically, using a high resolution field emission scanning electron microscope S-4700 (trade name) manufactured by Hitachi, Ltd., measurement was performed using an energy dispersive X-ray spectrometer equipped in the apparatus. . The acceleration voltage of the electron beam was 20 kV, and the electron beam beam diameter was 1 μm or less. In accordance with the description in this document, a region having a high phosphorus element content and a point having a low phosphorus element content were selected, and the characteristic X-ray intensity derived from the phosphorus element K-ray was measured at each point in a 200 μm square region. The ratio (maximum value / minimum value) was determined from the maximum value (the maximum value of the phosphorus element-containing characteristic X-ray intensity) and the minimum value (minimum value of the phosphorus element-containing characteristic X-ray intensity) of each measured value. . Hereinafter, this ratio is also simply referred to as “maximum value / minimum value”. The larger this value, the more localized the phosphate ester in the heat resistant slipping layer. Further, by the method described in detail in the above [Best Mode for Carrying Out the Invention], the localized region of the phosphorus element X-ray intensity (maximum region of characteristic X-ray derived from the K-line of the phosphorus element) and the corresponding region. The maximum value (maximum maximum value) of the X-ray intensity was determined, and the coefficient of variation (hereinafter also simply referred to as “variation coefficient”) of those maximum values was determined according to the above formulas (1) to (3). These values are used as a scale indicating a distribution state of a localized portion of a predetermined phosphate ester having an OH group or a salt thereof (hereinafter, these are collectively abbreviated as “phosphate ester localized portion”). . Here, the smaller the value of the coefficient of variation, the more uniform the distribution of the phosphate ester localized portion in the heat resistant slipping layer.
The above values were obtained for each sample in the same manner except that the thermal transfer sheet (101) was changed from the thermal transfer sheet (102) to (109).
Table 1 shows the structures of the heat-resistant slip layers of these heat-sensitive transfer sheets and the above values.

  From Table 1, in the samples (101) to (103) using only the phosphate ester having no OH group outside the scope of the present invention, the phosphate ester in the heat resistant slipping layer was changed even if the dispersion condition was changed. The distribution state cannot be within the scope of the present invention. By examining the dispersion conditions in samples (104) to (109) using phosphate esters having an OH group within the scope of the present invention, samples (105), (106), (108) and (109) The distribution state of the phosphate ester in the heat-resistant slipping layer) can be within the scope of the present invention. It can also be seen that the dispersion conditions for making the distribution state of the phosphate ester in the heat resistant slipping layer more preferable range differ depending on the type of phosphate ester used, and the dispersion condition cannot be defined unconditionally.

(Image formation, measurement and evaluation)
Using the thermal transfer sheet (101) and the thermal transfer image receiving sheet, five black solid images were continuously printed on a thermal transfer image receiving paper having a size of 152 mm × 102 mm by a thermal transfer type printer. The length of the thermal transfer sheet before and after printing was measured for the first and fifth sheets of five continuous prints, and the length before printing was calculated by subtracting the length before printing from the length after printing. Further, the elongation ratio was obtained by dividing the elongation length by the length of the print portion. When the rate of elongation is large, the frequency of occurrence of image defects is high, and when the rate of elongation is small, the frequency of occurrence of image defects is low.
The thermal transfer printer has a printing resolution of 300 dpi, yellow, magenta, and cyan recording energy of 1.9 J / cm ² , line speed of 1.3 msec / line, and recording energy of 2.0 J / cm ² and line speed of 0.7 msec. / I went on the line. The maximum temperature reached by TPH was 410 ° C. A solid black image was printed in the same manner except that the thermal transfer sheet (101) was changed from (102) to (109). When printing 5 sheets continuously for a plurality of thermal transfer sheets, a printer standby time of 20 minutes or more was provided between each 5 sheets of continuous printing.
Separately, a sheet in which only the heat-resistant slip layer was formed on the base film was prepared in the preparation of the thermal transfer sheet. The cyan dye layer surface of the heat-sensitive transfer sheet (101) and the heat-resistant slip layer surface of the sheet in which only the heat-resistant slip layer was formed on the base film were adhered, and stored for 2 weeks in an environment of 40 ° C. and 90% relative humidity. . After storage, the heat resistant slipping layer surface and the cyan dye layer surface were peeled off. Measure the transmission optical density of the sheet on which only the heat-resistant slip layer was formed before and after storage, and subtract the optical density value before storage from the optical density value after storage to determine the range of change in optical density, to the heat-resistant slip layer This was a measure of the amount of dye transferred. The smaller this value is, the more difficult it is to transfer the dye to the heat-resistant slipping layer.
Separately, the above values were obtained for each sample except that the thermal transfer sheet (101) was changed from (102) to (109).
The evaluation results are shown in Table 2 below.

  From Table 1 and Table 2, it can be seen that the high-speed printing (time per line is shorter) increases the elongation of the thermal transfer sheet in any sample. From the comparison of the samples (104) and (109) with respect to the samples (101) to (103), by using a phosphate ester having an OH group within the scope of the present invention as the phosphate ester, the elongation of the thermal transfer sheet is increased. However, it can be seen that, particularly in the case of the first print of high-speed printing, the elongation is large, and at the same time, the transfer of the dye to the heat-resistant slipping layer is large. From samples (104) to (109), a phosphate ester having an OH group within the scope of the present invention is used as the phosphate ester, and the distribution state of the phosphate ester in the heat resistant slipping layer is further within the scope of the present invention. It can be seen that the elongation of the thermal transfer sheet can be reduced by including only the inner sample, including high-speed printing and the first print, and dye transfer to the heat resistant slipping layer can be suppressed.

Example 2
Preparation of heat-sensitive transfer sheet (201) For the heat-sensitive transfer sheet (106) of Example 1, zinc stearate contained in the dispersion for heat-resistant slipping layer was not used, and the phosphate ester in the heat-resistant slipping layer was not used. A thermal transfer sheet (201) was prepared in the same manner except that the dispersion conditions were changed in order to change the distribution.
Preparation of thermal transfer sheet (202) 3.5 parts by mass of mono- and di-stearyl phosphate ester mixture (melting point: 62 ° C) of heat-resistant slip layer dispersion for mono- and di-heat-sensitive transfer sheet (201) -A heat-sensitive transfer sheet (202) was prepared in the same manner except that the zinc salt of stearyl phosphate ester (melting point 190 ° C) was changed to 3.5 parts by mass and 0.5 parts by mass of zinc stearate was used.
Preparation of thermal transfer sheet (203) 0.5 parts by mass of 3.5 parts by mass of mono- and di-stearyl phosphate ester mixture (melting point: 62 ° C.) of heat-resistant slip layer dispersion for thermal transfer sheet (201) In the same manner except that 3.0 parts by mass of zinc salt of mono- and di-stearyl phosphate (melting point 190 ° C.) and 0.5 parts by mass of zinc stearate are used. A sheet (203) was produced.

  The produced thermal transfer sheets (201) to (204) were measured and calculated for characteristic X-ray intensity in the same manner as in Example 1. Table 3 shows the composition of the heat-resistant slipping layer of these thermal transfer sheets and the values obtained from the measurement and calculation of the characteristic X-ray intensity, including the results of the thermal transfer sheet (106) of Example 1.

(Image formation, measurement and evaluation)
Other than changing the recording energy of the thermal transfer type printer to 1.9 J / cm ² and the line speed of 1.3 msec / line to the recording energy of 2.1 J / cm ² and the line speed of 0.5 msec / line with respect to Example 1. In the same manner, image formation, measurement and evaluation were performed.
The evaluation results are shown in Table 4 below.

  From Table 3, any one using phosphate esters within the scope of the present invention can make the distribution state of phosphate esters in the heat resistant slipping layer within the scope of the present invention. Also, from Table 4, comparison of samples (106) and (201) shows that by using zinc stearate in combination, the elongation of the thermal transfer sheet can be suppressed even in high-speed printing, and at the same time, a dye for the heat-resistant slipping layer. It can be seen that the transfer of can also be suppressed. From the comparison of samples (106), (202) and (203), among the phosphate esters within the scope of the present invention, the sample using phosphate ester having a melting point of 62 ° C. is sensitive to further high-speed printing. It can be seen that the elongation of the thermal transfer sheet can be more effectively suppressed.

Example 3
Preparation of Thermal Transfer Sheet (301) For the thermal transfer sheet (203) of Example 2, mono- and di-stearyl phosphate zinc salts (melting point 190 ° C.) 3.0 of the dispersion for the heat resistant slipping layer. The composition of the dispersion for the heat-resistant slipping layer was changed to 0.5 parts by mass and 2.5 parts by mass of the mono- and di-polyoxyalkylene alkyl ether phosphate ester mixture (melting point -2 ° C) was used. The thermal transfer sheet (301) was changed in the same manner except that the heat treatment conditions for carrying out the crosslinking reaction between the isocyanate and the polyol were changed to 55 ° C. for 2 days. A thermal transfer sheet (302) was prepared in the same manner except that it was changed to 42 ° C for 18 days, and a thermal transfer sheet (304) was prepared in the same manner except that it was changed to 36 ° C for 30 days. It was. Furthermore, the polyacryl polyol resin of the dispersion for the heat-resistant slip layer is replaced with polyvinyl butyral resin in the same amount as the solid content for the heat-sensitive transfer sheets (301) to (304), and the polyisocyanate of the heat-resistant slip layer coating liquid. Heat-sensitive transfer sheets (305) to (308) were prepared in the same manner except that the amount of polyisocyanate was changed so that the ratio of reactive groups between the resin and the resin (-NCO / OH) was 1.1. . After the heat treatment, unreacted isocyanate groups were confirmed by IR measurement, and it was confirmed that they were sufficiently reacted under any heat treatment conditions.

  The produced thermal transfer sheets (301) to (308) were measured and calculated for characteristic X-ray intensity in the same manner as in Example 1. Table 5 shows values obtained from the measurement and calculation of the resin, heat treatment conditions and characteristic X-ray intensity of the heat-resistant slip layer of these thermal transfer sheets.

(Image formation, measurement and evaluation)
Image formation, measurement, and evaluation were performed in the same manner as in Example 2 except that the thermal transfer sheets (301) to (308) were used.
The evaluation results are shown in Table 6 below.

  From Table 6 above, all of the samples (301) to (308) are within the scope of the present invention, but the thermal transfer sheet is stretched by setting the heat treatment conditions to 40 ° C to 53 ° C and 1 day to 20 days. It can be seen that the image can be made smaller including the first sheet of the high-speed print, and the transfer of the dye to the heat-resistant slip layer can be suppressed to a lower level. Moreover, it turns out that the effect of this invention expresses more by using polyacryl polyol as resin of a heat-resistant slipping layer.

Claims (13)

A heat-sensitive transfer sheet having a dye layer containing a heat transferable pigment and resin on one surface of a base film, and having a heat-resistant slip layer containing a lubricant and a resin on the other surface, The heat-resistant slip obtained by irradiating an electron beam having a beam diameter of 1 μm or less, which contains a compound represented by the following general formula (1) as a lubricant and is accelerated to 20 kV from the heat-resistant slip layer side of the thermal transfer sheet. When the characteristic X-ray intensity derived from the K-line of the phosphorus element in the layer is measured with an energy dispersive X-ray spectrometer at each point in the 200 μm square area, the maximum value of the intensity in the area is minimum. There are a plurality of maximum regions having a maximum value of the characteristic X-ray intensity derived from the phosphorus element K-ray within the region, and the characteristic X-ray intensity between these maximum regions The standard deviation of the maximum value of Thermal transfer sheet variation coefficient obtained by dividing the average intensity is equal to or is 0.25 or less.
General formula (1)
{(R ¹ O) (R ² O) P (═O) O} _m M
(In General Formula (1), M represents a hydrogen atom, a metal ion, or an ammonium ion. R ¹ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aryl group. R ² represents Represents a hydrogen atom, a metal ion, an ammonium ion, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aryl group, and m is the same as the valence of M and represents a number of 1 to 6.   The thermal transfer sheet according to claim 1, wherein the maximum value of the intensity is at least 3.0 times or more than the minimum value, and the coefficient of variation of the distribution is 0.22 or less.   The heat-sensitive transfer sheet according to claim 1 or 2, wherein the compound represented by the general formula (1) contained in the heat-resistant slipping layer has a melting point of 40 ° C to 100 ° C.   The heat-sensitive transfer sheet according to any one of claims 1 to 3, wherein the heat-resistant slipping layer further contains a polyvalent metal salt of an alkyl carboxylic acid.   The thermal transfer sheet according to any one of claims 1 to 4, wherein the heat-resistant slipping layer further contains talc particles.   When the content of the talc particles and the content of the compound represented by the general formula (1) are 100 parts by mass of the content of the compound represented by the general formula (1), The thermal transfer sheet according to claim 5, wherein the content of talc particles is 30 parts by mass or more.   The heat-sensitive transfer sheet according to any one of claims 1 to 6, wherein the base film has an easy-adhesion layer on at least one surface of the base film.   The heat-sensitive transfer sheet according to any one of claims 1 to 7, wherein the resin of the heat-resistant slipping layer has two or more hydroxyl groups in the polymer chain length terminal or polymer structure of the resin.   The thermal transfer sheet according to claim 8, wherein the resin is a polyacryl polyol resin.   The thermal transfer sheet according to claim 8 or 9, wherein the resin of the heat resistant slipping layer is crosslinked.   The thermal transfer sheet according to claim 10, wherein the crosslinking reaction in the crosslinking is performed in a temperature range of 40 ° C. to 53 ° C. and in a period of 1 day to 20 days.   The thermal transfer sheet is a thermal transfer sheet used in combination with a thermal transfer image-receiving sheet having a heat insulating layer containing a hollow polymer latex and a receiving layer containing a polymer latex on a support. The heat-sensitive transfer sheet according to any one of claims 1 to 11. On a support, a thermal transfer image-receiving sheet having a heat insulating layer containing a hollow polymer latex and a receiving layer containing a polymer latex, and a dye layer containing a dye and a resin capable of thermal transfer on one surface of the substrate film A heat-sensitive transfer sheet on which the heat-resistant slip layer containing a lubricant and a resin is formed on the other surface, and the image-receiving layer of the heat-sensitive transfer image-receiving sheet and the dye layer of the heat-sensitive transfer sheet are overlapped, An image forming method for forming an image by applying thermal energy according to a signal from the heat-resistant slipping layer side of the heat-sensitive transfer sheet, wherein the heat-sensitive transfer sheet has the following general formula as a lubricant in the heat-resistant slipping layer. In the heat-resistant slipping layer obtained by irradiating an electron beam having a beam diameter of 1 μm or less that contains the compound represented by (1) and is accelerated to 20 kV from the heat-resistant slipping layer side of the heat-sensitive transfer sheet. When the characteristic X-ray intensity derived from the K-line of phosphorus element is measured by an energy dispersive X-ray spectrometer at each point in the 200 μm square area, the maximum value of the intensity in the area is smaller than the minimum value. There are a plurality of maximum regions having a maximum value of characteristic X-ray intensity derived from phosphorus element K-rays in the region, and the maximum value of the characteristic X-ray intensity between these maximum regions An image forming method, wherein a coefficient of variation obtained by dividing a standard deviation by an average of the characteristic X-ray intensity is 0.25 or less.
General formula (1)
{(R ¹ O) (R ² O) P (═O) O} _m M
(In General Formula (1), M represents a hydrogen atom, a metal ion, or an ammonium ion. R ¹ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aryl group. R ² represents Represents a hydrogen atom, a metal ion, an ammonium ion, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aryl group, and m is the same as the valence of M and represents a number of 1 to 6.