JP2000118153A - Thermal transfer image receiving sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer image receiving sheet having a receiving layer formed by using a powder composition, the thermal transfer image receiving sheet having excellent abrasion resistance and scratch resistance on the surface of the receiving layer. SOLUTION: After a powder layer 3 made of a powder composition containing a dye-dyeable resin is provided on the surface of a base material 2, the powder layer 3 is heated and melted, and is fixed by pressing to form a receiving layer. Transfer receiving sheet 1 comprising a substrate 4 and a receiving layer 4 provided on a substrate 2
In the above, the amount of the receiving layer 4 peeled off by a wear test was 4 g / m 2.
² or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer image-receiving sheet which is used by being superposed on a thermal transfer sheet, and more particularly to a thermal transfer image-receiving sheet having a dye receiving layer formed by using a powder composition.

[0002]

2. Description of the Related Art Conventionally, as an image receiving sheet of a thermal transfer recording system using a sublimable dye, a composition containing a resin having a dye-dyeing property is coated on the surface of a base sheet such as synthetic paper, and dried to form a dye. Those formed with a receiving layer are known.

[0003] In the conventional thermal transfer image-receiving sheet, the dye-receiving layer has been manufactured using a solvent-type coating composition.
In recent years, a method for producing a thermal transfer image-receiving sheet using a powder coating composition as a composition of a dye receiving layer has been proposed (for example, JP-A-8-112974, JP-A-8-2).
No. 24970). A powder coating composition (a so-called toner) is prepared by melt-kneading a powder coating composition containing a resin component, a white colorant, a charge controlling agent, an anti-offset agent, etc., cooling, and then pulverizing to obtain an appropriate average particle size. What classifies so that it may have is used.

[0004] In the above-mentioned publication, there is a description of an electrophotographic production method as a method for forming a dye receiving layer. In this method, toner is charged on the surface of a sheet serving as a base material such as plain paper by frictional charging or the like, and the toner is attached to the drum surface charged to the opposite polarity by electrostatic attraction. It is transferred to a processed substrate, heated and fixed.

[0005]

However, in the thermal transfer image-receiving sheet having a receiving layer formed by using the above-mentioned powder composition, the receiving layer uses the powder composition as a constituent material. It is extremely difficult to obtain a continuous film having no defects. Therefore, compared with a thermal transfer image-receiving sheet having a receiving layer formed by coating a composition obtained by dissolving the previous dye-dyeable resin in a solvent, the surface strength of the receiving layer, particularly the rub resistance, and the abrasion resistance are inferior. However, there was a problem in practical use.

A specific problem with the thermal transfer sheet is that when the image is actually printed using a printer, the powder composition of the receiving layer is reduced when the surface of the receiving layer is rubbed by a grip roll or other transport system. In some cases, the object was peeled off, the surface smoothness was reduced, and the image quality of printing was reduced.

In addition, when the peeled-off powder composition adheres to a transport roll of a printer and changes the coefficient of friction, it hinders accurate transport of an image-receiving sheet, causing misregistration of printing or causing serious problems. Sometimes resulted in poor transport.

In some cases, the powder adhering to the inside of the printer is transferred to the surface of the thermal head or the surface of the image receiving sheet to cause printing failure.

In addition, when the image receiving sheet is handled or when writing is performed on the surface of the image receiving sheet with a writing instrument or the like, the powder composition peels off and contaminates the surroundings, and the receiving layer surface is damaged. May have occurred.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art. In a thermal transfer image-receiving sheet having a receiving layer formed by using a powder composition, the surface of the receiving layer has abrasion resistance and scratch resistance. An object of the present invention is to provide a thermal transfer image-receiving sheet having excellent heat resistance.

[0011]

The present invention relates to (1) a thermal transfer image-receiving sheet having a receiving layer formed from a powder composition containing a dye-dyeable resin on a base material made of plain paper. The amount of peeling in the wear test on the surface of the receiving layer was 4.0 g / m.
² or less, thermal transfer image receiving sheet,
(2) The heat transfer image-receiving sheet according to claim 1, wherein the base material is plain paper.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, after a powder layer 3 made of a powder composition containing a dye-dyeable resin is provided on the surface of a substrate 2, the powder layer 3 is heated and melted, and pressurized as necessary. And fixing to form the receiving layer 4, and as shown in FIG.
The present invention relates to a thermal transfer image receiving sheet 1 on which a receiving layer 4 is provided.

In the present invention, the term "wear test" refers to a method using a Taber-type friction tester. Various methods are known as methods for evaluating the surface strength, especially frictional strength and scratch resistance, of sheet-shaped articles, from sensual means to means capable of quantitative evaluation. Among them, the present inventors have found that the Taber abrasion test is at least the surface strength of a thermal transfer image-receiving sheet formed by applying a powder composition comprising a resin having dye-dyeing properties to form a receptor layer, and in particular, the frictional strength. It was found to be most suitable for evaluating scratch resistance.

In the Taber type friction test, as shown in FIG. 3, a test piece 5 (about 100 mm in diameter) of a thermal transfer image-receiving sheet is weighed and attached to a rotating flat plate-shaped rotating table 6 with the receiving layer side as a surface. . Next, two wear wheels 7 and 8 (in which a high friction element made of inorganic particles such as corundum is provided in a cylindrical shape around the rotation axis) which can be rotated vertically with respect to the rotary table are vertically loaded with a constant load. To rotate the turntable 6 at a predetermined rotation speed by a constant number of rotations. The rotation axis of the turntable and the rotation axis of the wear wheel do not intersect, and the wear wheel rotates while rubbing the surface of the test piece 5 with the rotation of the turntable. The turntable 5 and the wear wheels 7 and 8 rotate in a relationship indicated by arrows in FIG. After the predetermined rotation, the test piece 5 is removed from the turntable 6 and the weight is measured. Further, the surface of the test piece 5 is visually observed to observe the degree of the damage. The amount of abrasion (that is, the amount of peeling of the receiving layer) is calculated from the weight of the test piece before and after the test and the area A (m ² ) of the portion rubbed by the abrasion wheel according to the following [Equation 1]. In the present invention,
The load cone is 250 g for each worn wheel, and the number of revolutions is 5
Zero rotation was performed.

[0015]

(Equation 1)

In the above-mentioned abrasion test, the amount of peeling of the receiving layer is:
When it exceeds 4 g / m ² , the thermal transfer image-receiving sheet has poor frictional strength and abrasion resistance, and tends to cause the various problems described above. On the other hand, the amount of the receiving layer peeled was 4 g / m
If it is ² or less, a thermal transfer image-receiving sheet free from the above-mentioned problems can be obtained. More preferably, the peeling amount of the receiving layer in the wear test is 3.0 g / m ² or less.

As a specific means for controlling the amount of peeling in the wear test of the receiving layer to 4 g / m ² or less, for example, fixing conditions for fixing the powder composition are selected so that sufficient fixing is performed. The means to do it are raised. Hereinafter, specific means for performing sufficient fixing will be described.

A case where a thermal transfer image receiving sheet is manufactured using the manufacturing apparatus shown in FIG. 4 will be described. The manufacturing apparatus shown in FIG. 4 includes a feeding roll 11 for feeding a roll around which a long base material is wound, and a powder coating booth for forming a powder layer on the base material 2 including a powder supply device 12. 13, a fixing device 14 for fixing the powder layer 3 on the base material 2 to form the receiving layer 4, and a winding device 15 for winding the formed thermal transfer image receiving sheet.

First, the base material 2 is fed from the feeding roll 11 into the powder coating booth 13 and the powder composition is supplied from the powder supply device 12 to the surface of the base material 2 to form the powder layer 3. You. Next, the powder layer 3 is sent to the fixing device 14 and heated and pressed to form a receiving layer. Finally, it is wound into a roll by the winding device 15. As a method for supplying the powder composition, an electrostatic powder coating method, an electrophotographic method, or the like can be used.

Examples of the heating means at the time of fixing include indirect heating using hot air, infrared rays, microwaves or the like, and direct heating using a heating roll or a heating plate. These heatings may be performed alone or in combination with a plurality of heating means. In particular, when using plain paper as the base material, using a direct heating means such as a heating roll or a pressure press pushes the powder composition into the irregularities derived from the pulp on the plain paper base material surface, so-called This is a preferable means because a sealing effect is produced. Further, by using a heating roll having a smooth surface, it is possible to make the surface of the receiving layer smooth. In direct heating, it is preferable that the roll or the plate is subjected to a fluororesin treatment, preferably a PFA treatment, since the releasability from the powder composition is improved. In the thermal transfer image-receiving sheet, since the uniformity of the surface of the image-receiving layer greatly affects the image quality and the like, it is extremely important to form the surface smoothly, so a direct heating means sandwiched between two rolls is effective. .

The specific surface treatment of the heating roll is as follows. It is also preferable to carry out polishing after performing the following treatment in accordance with the desired surface smoothness. Fluororesin coating: The surface of the roll iron core is coated with a fluororesin having excellent releasability, preferably PFA. Fluororesin tube: A tube of fluororesin, preferably PFA, having excellent releasability is wound around the surface of the roll iron core. When the roll surface requires flexibility, it is also preferable to wind a rubber around the roll iron core, and wind a fluororesin tube thereon. Silicone rubber: A silicone rubber with excellent heat resistance and releasability is wound around the surface of a roll iron core. Fluoro rubber: Wrap a fluoro rubber with excellent heat resistance and releasability around the surface of the roll iron core.

As a combination of a plurality of heating means, for example, after the powder composition is applied on a plain paper base material, the composition is preheated by an infrared heater and heated, and then heated using a heating roll. By performing heat and pressure fixing, both sufficiently strong fixing and high production efficiency can be achieved. It is also effective to provide a plurality of sets of heating rolls.

In order to fix the powder layer sufficiently firmly when forming the receiving layer, in the various fixing methods described above,
It is necessary to optimize various conditions such as heating temperature, pressurizing pressure, heating time, and pressurizing time. These conditions are adjusted according to the composition of the powder composition of the dye receiving layer to be used, the type of the substrate, the thickness of the substrate, and the like, so that the amount of peeling by the abrasion test of the receiving layer is 4%.
g / m ² or less.

As the substrate 2 of the thermal transfer image-receiving sheet, plain paper, synthetic paper, plastic sheet and the like are used, and plain paper is particularly preferred. As the plain paper used for the base material 2, a paper mainly composed of pulp that is usually used is used. Examples of the plain paper include high-quality paper, art paper, lightweight coated paper, lightly coated paper, coated paper, cast coated paper, synthetic resin or emulsion impregnated paper, and the like. The thickness of plain paper is 40 to 300 μm, preferably 60 to 200 μm
It is about. In order to give the resulting thermal transfer image-receiving sheet a high texture of plain paper, the total thickness of the thermal transfer image-receiving sheet is desirably about 80 to 200 μm.

The receiving layer 4 is formed from a powder composition mainly composed of a dye-dyeable resin. The powder composition, in addition to the dye-dyeable resin, a release agent for preventing the receiving layer from fusing with the thermal transfer sheet when used after being used as a thermal transfer image-receiving sheet, when producing a thermal transfer image-receiving sheet A charge control agent for adjusting the chargeability as a powder coating, a white colorant for imparting concealment, an anti-offset agent, a fluidity improver, and the like can be added thereto.

Examples of the dye-dyeable resin include saturated polyester resin, polyamide resin, polyacrylate resin, polycarbonate resin, polyurethane resin, polyvinyl acetal resin, polyvinyl chloride resin, polyvinyl acetate resin, polystyrene resin, and styrene-acrylic resin. Resin, styrene-butadiene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl toluene-acryl resin, cellulose resin and the like. These resins are
They can be used alone or in combination of two or more.
The amount of the dye-dyeable resin is 70% by weight in the powder composition.
If it is less than 70%, the dye-dyeing property is not sufficiently exhibited, and the printing sensitivity may be lowered. Therefore, it is preferable to use 70% by weight or more of the powder composition.

As the release agent to be added to the powder composition, silicone oil, phosphate ester plasticizer, fluorine compound, various waxes and the like can be used, but silicone oil is preferable. As silicone oil,
Epoxy modification, alkyl modification, amino modification, carboxyl modification, alcohol modification, fluorine modification, alkyl aralkyl polyether modification, epoxy polyether modification,
A modified silicone oil such as a polyether-modified silicone oil is preferably used. Among them, a reaction product of a vinyl-modified silicone oil and a hydrogen-modified silicone oil, and an amino-modified silicone and an epoxy-modified silicone, or a modified silicone having active hydrogen and active hydrogen A cured product of a curing agent that reacts with the above is preferred. The curing agent having active hydrogen is a non-yellowing type isocyanate compound, specifically, XDI, hydrogenated XDI, TMXDI, HDI, IDI
PDI and the respective adducts / burettes, oligomers and prepolymers are preferred. As the wax, those having a melting point in the range of 50 to 150 ° C. are preferable. For example, fluid or solid paraffin, polyolefin wax such as polyethylene and polypropylene, aliphatic metal salt, fatty acid ester, partially saponified fatty acid ester, higher fatty acid, higher fatty acid Examples include alcohols, silicone varnishes, amide waxes, aliphatic fluorocarbons and modified products thereof. The addition amount of the release agent is preferably 0.2 to 30 parts by weight based on 100 parts by weight of the resin forming the dye receiving layer.

The charge control agent added to the powder composition is for controlling the charge polarity and the charge amount of the powder composition when performing the electrostatic powder coating, and is a known electrostatic latent agent. What is used for the toner for image development can be used. Examples of negatively chargeable charge control agents include 2: 1 metal-containing azo dyes,
Examples thereof include metal complexes of aromatic oxycarboxylic acids and aromatic dicarboxylic acids, sulfonylamine derivatives of copper phthalocyanine dyes, and sulfonamide derivative dyes of copper phthalocyanine. Examples of the positive charge control agent include various nigrosine dyes in addition to quaternary ammonium compounds, alkylpyridinium compounds and alkylpicolinium compounds. The addition amount of the charge control agent is preferably 0.1 to 10 parts by weight, particularly preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the resin of the receiving layer.

The white colorant added to the powder composition is for imparting hiding power and whiteness to the dye receiving layer.
Examples include calcium carbonate, talc, kaolin, titanium oxide, zinc oxide and the like. The amount of white colorant added is
The amount is preferably 10 to 200 parts by weight based on 100 parts by weight of the resin of the dye receiving layer. If the amount of the white colorant is less than 10 parts by weight, the effect of adjusting the color tone is poor, and if it exceeds 200 parts by weight, the dispersion stability in the dye receiving layer is reduced, and the performance of the resin in the dye receiving layer is sufficiently obtained. It may not be possible.

The fluidity modifier added to the powder composition includes:
This is for improving the fluidity of the powder composition, and examples thereof include hydrophobic silica.

The powder composition may contain coloring materials such as various pigments, dyes and fluorescent whitening agents as components other than the above components. When a thermal transfer image receiving sheet is used as a proofreading output material for printing proofreading, and when the color tone is matched with the corresponding printing paper, a desired color tone can be obtained by appropriately blending these colorants in the powder composition.

After the above components are appropriately mixed, melted, kneaded and uniformly dispersed, the powder composition is cooled,
After pulverization, if necessary, it is obtained by classifying to a desired average particle size. The average particle size of the powder composition is 1 to
It is preferably 30 μm, more preferably 5 to 15 μm.

When paper is used as the base material, the receiving layer 4 formed from the powder composition is preferably formed to have a substantial thickness of 7 μm or more. If the thickness of the receiving layer is less than 7 μm, there is a possibility that sufficient image quality and printing sensitivity may not be achieved due to the influence of surface irregularities derived from the pulp shape of the plain paper as the base material. Further, if the substantial thickness of the receiving layer 4 is 7 μm or more, the image quality and the printing sensitivity are satisfied.
The upper limit is not particularly limited, but if the thickness of the receiving layer is unnecessarily thick, the cost increases. Therefore, the upper limit of the substantial thickness is preferably 30 μm.

The actual thickness of the receptor layer 4 is determined by the thickness of the plain paper as the base material before coating and the thickness of the thermal transfer image-receiving sheet after the powder composition is coated and fixed to form the receptor layer 4. It can be determined by measuring. The inside of the dye receiving layer may be a discontinuous coating layer in which voids, cracks, and the like are formed, as long as the measured thickness is 7 μm or more. In order to make the thickness 7 μm or more, 1) the coating amount of the powder composition is set to a certain value or more. 2) The heating temperature and the pressing pressure are adjusted to melt the powder composition and permeate the plain paper. And the like.

When a thermal transfer image-receiving sheet is used, a sublimation type thermal transfer sheet used in a sublimation transfer recording system is used as the thermal transfer sheet. Application of thermal energy at the time of thermal transfer can use a known means, for example,
An image can be formed by applying a thermal energy of about 5 to 100 mj / mm ² by controlling a recording time by a recording device such as a thermal printer (for example, a printer Rainbow M2720 manufactured by 3M).

[0036]

[Powder coating material composition (all units are parts by weight)]

 -80 parts of polyester resin (Mitsubishi Rayon Co., Ltd .: Diacron FC-611)-20 parts of styrene-acrylic resin (Mitsubishi Rayon Co., Ltd .: FB-206) 20 parts-Charge control agent (Orient Chemical Co., Ltd .: Bontron P-51) 4 Part ・ Titanium oxide (Tochem Products: TCA888) 2 parts ・ Amino-modified silicone (Shin-Etsu Chemical: X22-349) 1 part ・ Epoxy-modified silicone (Shin-Etsu Chemical: KF-393) 1 part

After the raw materials having the above composition were mixed by a mixer, they were heated and melted and kneaded by a melt kneader. The mixture was cooled and solidified, then pulverized and classified to obtain a powder composition having an average particle size of 8 μm. 2 parts by weight of a hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd .: RA-
200H) to obtain a powder coating.

The above powder coating was applied and fixed on the surface of plain paper by the following electrostatic powder coating method to obtain a thermal transfer image-receiving sheet of Example 1. Further, the roll temperature and the roll speed were changed as shown in Table 1, and thermal transfer image-receiving sheets of other examples and comparative examples were obtained.

[Electrostatic powder coating method] ・ Electrostatic powder coating equipment: GX5000S, manufactured by Nippon Parkerizing Co., Ltd. ・ Hand gun: GX106N, manufactured by Nippon Parkerizing Co., Ltd. [Fixing conditions] ・ Heat roll diameter: Both sides of the receiving layer and the backside Diameter 40mm ・ Heat roll material: Surface treatment of PFA on iron roll ・ Heating temperature: as shown in Table 1 ・ Roll speed: as shown in Table 1 ・ Pressure pressure: 2 kg per 25 cm of roll length ・ Roll surface roughness (Ra): Both 0.5 μm for both rolls ・ Roll mirror gloss (Gs45 °): 8.0%

The thermal transfer image-receiving sheet prepared as described above was subjected to the abrasion test described above, and the amount of the powder composition peeled per unit area was measured. The test conditions are as follows. The peel amount was calculated based on the above [Equation 1].

Testing machine: ROTARY AB manufactured by Toyo Seiki
RASION TESTER wear wheel: CARIB made by TABER INDUSTROY
RASE CS-10 (Two identical ones are used.) Load: A load cone of 250 g is used for each wear wheel Diameter of a test object: 10.7 cm Area of wear part: 3.0 × 10 ⁻³ m ² Rotation speed: 60 Rotation / min Number of rotations: 50

[Abrasion Test Surface State] After the abrasion test, the abraded surface of the thermal transfer image-receiving sheet of each of the examples and comparative examples was visually observed. Table 1 shows the results. The evaluation criteria are as follows. ：: The surface gloss is reduced and scratches are observed, but no noticeable peeling of the receiving layer is observed. Δ: Part of the receiving layer was peeled off, and the surface of the base paper appeared. C: Almost all of the receiving layer was peeled off, and the surface of the base paper was almost exposed.

[Tape Peeling Test] A Nichiban mending tape was applied to the receiving layer surface of the thermal transfer image-receiving sheet of each of Examples and Comparative Examples, and then the mending tape was peeled in a direction perpendicular to the receiving layer surface, and peeled. The state of the surface was visually observed. Table 1 shows the results. The evaluation criteria are as follows. ：: No cohesion failure occurred inside the base paper without peeling off at the interface between the receiving layer and the base paper. Δ: Cohesive failure inside the receiving layer. X: Peeled off at the interface between the receiving layer and the base paper.

[Print Quality] The thermal transfer image receiving sheets of the above Examples and Comparative Examples were printed using a sublimation transfer printer Rainbow 2720 manufactured by 3M and a dye transfer film for the same, and the print quality was evaluated. Printing is 4
Color Bk image (Y, M, C, Bk color tone value 50%) solid, 1 dot, 2 dot width Bk single color (100% / 10
0%) A thin line and an image were formed and subjected to printing and image evaluation. The print image quality was visually evaluated by sensory evaluation according to the following evaluation criteria. ：: good without missing prints, fine lines, etc. Δ: Missing print and slight blurring of fine lines are observed. X: Print missing, fine line fading is remarkable.

[0045]

As described above, the present invention relates to a thermal transfer image-receiving sheet in which a receiving layer formed from a powder composition containing a dye-dyeable resin is provided on a substrate made of plain paper. The amount of peeling in the wear test of the surface of the receiving layer was 4.0 g / m ^2.
By adopting the following configuration, a thermal transfer image-receiving sheet having good printing image quality and excellent abrasion resistance and scratch resistance of the surface of the receiving layer can be obtained. The defect of the thermal transfer image-receiving sheet having the layer formed could be improved.

That is, when the thermal transfer image-receiving sheet is rubbed in the conveying system, the receiving layer is peeled off, and there is no fear that the surface smoothness is reduced and the image quality of the image is deteriorated. There is no. Further, there is no fear that the powder adhering to the inside of the printer is transferred to the surface of the thermal head or the surface of the image receiving sheet to cause printing failure. In addition, a thermal transfer image-receiving sheet free from problems such as contamination when writing on the surface of the image-receiving sheet with a writing instrument or scratching of the surface of the receiving layer can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a powder composition is applied to a substrate surface.

FIG. 2 is a cross-sectional view illustrating an example of a thermal transfer image receiving sheet.

FIG. 3 is an explanatory diagram for explaining a wear test method.

FIG. 4 is a schematic view illustrating an example of a thermal transfer image receiving sheet manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal transfer image-receiving sheet 2 Substrate 3 Powder layer 4 Receiving layer

[Table 1]

Claims (2)

[Claims] 1. A thermal transfer image-receiving sheet having a receiving layer formed from a powder composition containing a dye-dyeable resin on a substrate, wherein the amount of peeling in a wear test of the surface of the receiving layer is 4. 0
g / m ² or less. 2. The thermal transfer image-receiving sheet according to claim 1, wherein the substrate is plain paper.