JP2528980B2 - Image receiving sheet for thermal transfer printing - Google Patents

Description

The present invention relates to an image-receiving sheet for a color printer, and more specifically, it is a thermal transfer, particularly an image-receiving sheet for a sublimation dye thermal transfer printer. The present invention relates to an image receiving sheet which is sharply received, has good running properties, and can be easily printed and written in advance on the surface opposite to the color printed surface. Such an image receiving sheet is convenient for use in postcards, cards and the like.

[Prior art]

Recently, the development of color printers has progressed, and in particular, thermal transfer printers have become possible to realize clear color images with a relatively compact device. For thermal transfer printing, methods such as sublimation transfer dye and wax-based molten ink are used.

Of these, the sublimation dye thermal transfer method is often used for small color printers and video printers as the mainstream of small non-impact printers, and an image receiving sheet that can obtain a clear image has been developed in the sublimation dye thermal transfer method. .

A sublimation dye thermal transfer printer uses a substrate such as a film or thin paper and an ink sheet coated with Y, M, and C three-color sublimation dye inks. An image receiving sheet coated with a dyeable resin or the like is superposed on the ink sheet, and the sublimation dye of each color is transferred from the ink sheet to the image receiving sheet by heat from the thermal head to form an image in a required concentration.

In order to obtain good quality printing on the image receiving sheet of a thermal printer using a thermal head including a thermal transfer printer, in order to obtain an image, use a substrate sheet containing a particularly preferred thermoplastic polymer material as a main component, Also, a biaxially stretched multi-layered film containing an inorganic pigment and polylorefin as a main component, or a film containing a thermoplastic polymer material as a main component such as a PET film is used as a base sheet. It has been known. In the image receiving sheet for a sublimation dye thermal transfer printer, a dyeing layer containing a dye-dyeing resin such as polyester as a main component, that is, an image receiving layer is formed on this substrate.

The image-receiving sheet using these substrate sheets has advantages that the thickness is uniform, the flexibility is high, and the thermal conductivity is smaller than that of paper made of cellulose fiber. It has the advantage that high prints can be obtained.

Further, the image receiving sheet is generally supplied as a single sheet. Therefore, when the conventional image receiving sheet is used, troubles such as misfeed due to the friction coefficient and the charging property occur.

Further, since the image receiving sheet is expected to be stored and used as a color print for a long period of time, an image receiving sheet that maintains a stable antistatic effect for a long period of time also in order to prevent adhesion of dust due to charging. Was expected to appear.

That is, even if the conventional image-receiving sheet was subjected to antistatic treatment, it was not effective at low humidity, and charging trouble occurred.
In particular, it is usually stored sealed before use,
Therefore, charging and blocking during storage have been problems.

Further, the conventional image-receiving sheet is inferior in writing property and printability. In particular, when it is used for postcards and the like, it is required to improve the writing property, the sizing property, and the printability, which has been a problem to be solved.

Pigment coating that gives printability to general printing paper etc.
It is not always suitable for a sheet made of a thermoplastic polymer material. Furthermore, in order to improve the conventional image-receiving sheet to a level satisfying the running property in a printer, many problems remain to be solved.

[Problems to be Solved by the Invention]

The present invention, when used in various thermal transfer printers including a sublimation dye thermal transfer system, has good printing, an image receiving surface having image recording suitability, and a back surface having good printing and writing suitability, and is excellent. Another object of the present invention is to provide an image receiving sheet for thermal transfer printing, which has excellent running property and antistatic suitability.

[Means and actions for solving the problem]

In view of the current state of the art as described above, the present inventors have found that when used in a thermal transfer printer such as a sublimation dye transfer system,
A clear image record can be obtained on the image receiving surface, and on the opposite surface,
The present invention has been completed as a result of intensive research on an excellent image-receiving sheet that is easy to write and print as on ordinary paper and has no fear of running such as heavy running due to static electricity.

The image-receiving sheet for thermal transfer printing of the present invention comprises a sheet-shaped base material containing a thermoplastic polymer material as a main component, and a thermal transfer colorant-receptive polymer material as a main component formed on one surface of the sheet-shaped base material. As an image receiving layer and a back surface coating layer formed on the opposite surface of the sheet-shaped substrate, wherein the back surface coating layer has an average primary particle size of 0.3 μm or less and an average particle size of 1 to 15 μm. It is characterized in that it contains as a main component a mixture of a pigment particle having a secondary particle diameter and a BET specific surface area of 10 m ² / g or more and a binder.

As shown in FIG. 1, the image-receiving sheet of the present invention comprises a sheet-shaped substrate 1, an image receiving layer 2 formed on the surface thereof, and a back surface (opposite surface) of the sheet-shaped substrate 1. And the back surface coating layer 3 formed on.

Conventionally, a paper produced by applying a mixture of a pigment such as clay and a binder on the surface has been used as a high-grade printing paper, etc., but such a mixture is applied to an image receiving layer of an image receiving sheet for thermal transfer. Use on the opposite side to print without impairing the image receiving property and running property of the image receiving sheet.
It has not yet been known to form a back coating layer having excellent writability.

The main component of the pigment used for the back surface coating layer having good printing and writing properties is preferably light calcium carbonate. Further, the Bekk smoothness of the back surface coating layer is preferably 30 seconds or more and 1500 seconds or less, and more preferably 500 seconds or less.

In the image-receiving sheet for thermal transfer printing of the present invention, the image-receiving layer is mainly composed of a resin material which is firmly dyed with a sublimable disperse dye transferred from the ink sheet and which can hold the received dye image. It is formed.
That is, such a sublimable dye that is easily dyed is a main component, and if necessary, a release agent, a white pigment, or the like is added.

Sublimation dye-dyeable resins having excellent dyeability, required mechanical strength, and required heat resistance, such as polyester resin, polycarbonate resin and other disperse dye dyeable, solvent-soluble resin When these are used alone or as a mixture of two or more of them, the image receptivity, sensitivity, and color density are good, the discoloration due to heat is small, and the running property is good.

The polyester resin mentioned here is a polymer obtained from a polycondensation reaction of a divalent carboxylic acid and a dihydric alcohol. As the dicarboxylic acid component, terephthalic acid,
Isophthalic acid, sebacic acid, etc. are used. Further, as the dihydric alcohol component, ethylene glycol, propylene glycol, neopentyl glycol or the like is used. Further, a divalent alcohol containing an aromatic compound, for example, a diol in which ethylene oxide is added to the hydroxyl groups at both ends of bisphenol A is also used.

The sheet-shaped substrate of the image-receiving sheet for thermal transfer printing of the present invention, a polyester film, a nylon film,
Polystyrene film, polyolefin film (for example, polypropylene film), biaxially stretched multilayer structure film base material (known as synthetic paper) containing polyolefin resin and inorganic pigment as main components, and this synthetic paper as polyester film Laminated sheets, laminated sheets of two or more of the above synthetic papers, or synthetic papers and various papers such as high-quality papers, medium-quality papers, Japanese papers, thin papers and coated papers (including fine coated papers and art papers) ) And a multi-layered combination of the above may be used.

In particular, a mono- or biaxially stretched multilayer structure film or a polyolefin synthetic paper containing an inorganic pigment is preferable as the sheet-shaped substrate in the present invention. As the multilayer structure,
A three-layer structure in which a paper-shaped monoaxially or biaxially stretched film is attached to the front and back surfaces of the base material layer, or a structure of four or more layers in which other layers are added to the paper-like layer and the base material layer. May be
As such a multi-layer structure synthetic paper, grade products such as FPG, ATG, SGG, and TPG of YUPO (trademark, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) are commercially available. On the surface. In addition, a small amount of coating layer is usually present on the surface for the purpose of improving adhesiveness and preventing static electricity.

In order to impart antistatic properties to the back surface coating layer, it is preferable to add a water-soluble anionic or cationic polymer material. Examples of the antistatic cationic polymer material include polyethyleneimine, an acrylic polymer containing a cationic monomer, and a cation-modified acrylamide polymer.Anionic polymer materials include polyacrylic acid and polystyrenesulfonic acid. is there. In order to reduce the surface specific resistance of the back surface coating layer to 10 ¹¹ Ω · cm or less, 1 to 30 parts by weight, preferably 5 to 20 parts by weight of the antistatic polymer material should be added to the back surface coating layer. preferable.

The pigment contained in the backside coating layer of the image-receiving sheet for thermal transfer printing generally has a large oil absorption and good ink absorption when its average primary particle size is reduced, but when it is too small, the adhesive strength of the backside coating layer deteriorates. Therefore, it cannot be practically used for forming a coating layer. If the average primary particle diameter of the pigment is 0.3 μm or more or the BET specific surface area is 10 m ² / g or less, the ink absorbability of such a pigment becomes poor. The average secondary particle diameter of the pigment in the back surface coating layer is 1 μm.
If it is below or the Bekk smoothness of the surface of the back surface coating layer is 1500 seconds or more, the friction of the obtained image receiving sheet becomes large, and the running property and the transport property are deteriorated. When the average secondary particle diameter is 15 μm or more or the Bekk smoothness of the surface of the back coating layer is 30 seconds or less, the surface of the back coating layer obtained is rough and the surface of the image receiving layer contacting it is The image quality of the image receiving surface is adversely affected, or the image receiving surface is damaged.

When a pigment having a small secondary particle size or a pigment particle that is still a primary particle is used, the surface of the back coating layer becomes dense,
Absorption of printing and writing ink deteriorates. It is also estimated that the running performance is not good.

In the image-receiving sheet of the present invention, the BET surface area of the pigment particles contained in the back surface coating layer is preferably 10 m ² / g or more, and more preferably 20 m ² / g or more. Further, the oil absorption of the pigment particles is preferably large, and in the case of light calcium carbonate, it is desirable that the oil absorption is 40 ml / g or more.

Light (precipitating) calcium carbonate is a relatively inexpensive pigment that satisfies the above conditions. Light calcium carbonate can change the particle shape, particle size and its distribution, and crystal system depending on the reaction conditions. The preferred calcium carbonate used in the present invention is a specially shaped crystal in which primary particles are aggregated. The preferred calcium carbonate used in the present invention can be obtained depending on the shape of various primary particles and secondary particles formed by aggregation, fusion, and the like.

It is not clear why the back surface coating layer of the image-receiving sheet shows good printing or writing, but the pigment serves as a spacer,
It is presumed that the running performance is improved.

In the present invention, as the pigment used in the back surface coating layer, in addition to light calcium carbonate, heavy calcium carbonate, various clays, calcined clay, titanium dioxide, aluminum hydroxide, talc, calcium silicate, calcium sulfate, magnesium silicate The synthetic amorphous silica and the like can be used alone or in combination of two or more kinds.

In the present invention, as the binder used in the back surface coating layer, a styrene-butadiene copolymer, an acrylic acid ester copolymer (including a homopolymer, the same applies hereinafter),
A latex such as a methacrylic acid ester copolymer is preferred. These polymers may be used alone as a latex, or may be used as a latex obtained by mixing two or more kinds. Further, vinyl acetate-based latex and water-soluble adhesives such as starch and polyvinyl alcohol can be used alone or in combination.

The amount of the above-mentioned pigment and binder used in the writable back surface coating layer is preferably 5 to 80 parts by weight, and more preferably 10 to 50 parts by weight, based on 100 parts by weight of the pigment. The amount of adhesive used is 5 per 100 weight of pigment
If the amount is less than 100 parts by weight, the coating strength of the coating layer is low, and if it exceeds 80 parts by weight, poor ink absorption occurs.

The writable back surface coating layer of the present invention can be produced using a coating technique and equipment similar to the coating technique and equipment used in the production of ordinary coated paper for printing. The smoothness of the surface also depends on the coating method and the smoothing treatment after coating.

〔Example〕

The image receiving sheet for thermal transfer printing of the present invention will be described with reference to examples. In the examples, “parts” means parts by weight of solid content.

Example 1 A mono- or biaxially-stretched synthetic paper (trademark: YUPO FPG150, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) containing an inorganic pigment and a polyolefin as main components was used as a base material-1. Also,
Paints 1 and 2 having the following compositions were prepared.

Paint 1 (for the back coating layer) Component Amount (part by weight) of precipitated calcium carbonate (trademark: Shironamarihana PX, Shiraishi Kogyo Co.) 100 carboxyl-modified styrene butadiene copolymer latex (trademark: S0668, Japan Synthetic Rubber 20) Oxidized starch (Trademark: Oji Ace A, Oji Cornstarch Co., Ltd.) 5 Sodium polyacrylate (Trademark: Aron T 40, Toagosei Co., Ltd.) 10 Average of the above white lead PX The primary particle size was 0.1 μm, the average secondary particle size was 1.8 μm, and the specific surface area was 24 m ² / g.

The coating material 1 was applied to the back surface of the base material-1 at a solid content of 7 g / m ² and dried. The smoothness of the surface of the generated backside coating layer was 300 seconds.

Paint 2 component amount (parts by weight) Polyester resin (trademark: Byron 200, manufactured by Toyobo Co., Ltd.) 100 Polyester silicone varnish (trademark: KR-5203, manufactured by Shin-Etsu Silicone Co., Ltd. 5 Toluene 200 Methylethylketone 200 Base material of the above paint 2 The surface of -1 was applied at a rate of 5 g / m ² (solid content).

A commercially available dye thermal transfer color printer (manufactured by Sony Corporation, UP-500) was used as the image receiving sheet for the dye thermal transfer printer.
The image quality and running property were evaluated by printing according to (0).

In addition, for printing and writing on the back side,
A water-based felt-tip pen was used to perform a sensory test for evaluation.

 The test results are shown in Table 1.

Example 2 The same operation as in Example 1 was performed. However, basis weight 104.5 g / m ²
A PET film having a thickness of 12 μm was laminated on the surface of the high-quality paper by a dry lamination using a polyether adhesive to obtain a base material-2.

The coating material 1 was applied to the back surface of the substrate-2 at a solid content of 5 g / m ² and dried to form a back surface coating layer. The surface smoothness was 150 seconds.

Further, the coating material 2 was applied on the PET film surface of the base material-2 at a solid content of 5 g / m ² and dried to form an image receiving layer.

 The test results are shown in Table 1.

Example 3 The same operation as in Example 1 was performed. However, the back surface of the substrate-1 was coated with a coating material 3 having the following composition at a solid content of 15 g / m ² and dried to form a back surface coating layer, the smoothness of which was 450 seconds. Further, the surface of Substrate-1 of the coating material ² was coated at a rate of 5 g / m ² to form an image receiving layer.

Paint 3 component amount (parts by weight) Light calcium carbonate (Trademark: Uni-bur70, Shiraishi Industry Co., Ltd.) 100 Acrylic ester copolymer LATEX (Trademark: Movinyl 720, Hoechst Synthesis Co., Ltd.) 20 Oxidation Starch (trademark: Oji Ace A, manufactured by Oji Corn Starch Co., Ltd.) 5 Antistatic agent (trademark: Saftomer ST6000, manufactured by Mitsubishi Yuka Co., Ltd.) 10 The average primary particle diameter of the above Unibur 70 is 0.17 μm, and the average secondary particle. The diameter was 2.5 μm and the specific surface area was 13 m ² / g.

 The test results are shown in Table 1.

Example 4 The same operation as in Example 1 was performed. However, a coating material 4 having the following composition was applied to the back surface of the base material-1 at a solid content of 15 g / m ² and dried to form a back surface coating layer, the smoothness of which was 50 seconds. In addition, the coating material 2 is applied to the surface of the base material at a solid content of 5 g / m ² ,
An image receiving layer was formed by drying.

Paint 4 component amount (parts by weight) Fine particle silica (Trademark: Fineseal, Tokuyama Soda Co., Ltd.) 100 Polyvinyl alcohol (Trademark: PVA117, Kuraray Co., Ltd.) 50 Antistatic agent (Trademark: Saftomer ST3100, Mitsubishi Petrochemical) 10) The average primary particle size of the fine seal is <0.1 μm,
The average secondary particle size was 2.8 μm and the specific surface area was 250 m ² / g.

 The test results are shown in Table 1.

Comparative Example 1 The same operation as in Example 1 was performed. However, the following composition paint 5
Was coated on the back surface of Substrate-1 at a solid content of 15 g / m ² , dried, and supercalendered to form a back coating layer having Beck's smoothness (Oken type) of 450 seconds. Further, the coating material 2 was applied on the surface of the substrate-1 at a solid content of 5 g / m ² and dried to form an image receiving layer.

3 components (parts by weight) Light calcium carbonate (Trademark: PC, Shiraishi Industry Co., Ltd.) 100 Acrylic ester copolymer LATEX (Trademark: Movinyl 720, Hoechst Kasei Co., Ltd.) 20 Oxidized starch ( Trademark: Oji Ace A, Oji Cornstarch Co., Ltd. 5 Antistatic agent (Trademark: SAFTMER ST6000, Mitsubishi Yuka Co., Ltd.) 10 The average primary particle size of the above PC is 0.46 μm, and the average secondary particle size is The surface area was 3.2 μm and the specific surface area was 5 m ² / g.

 The test results are shown in Table 1.

Comparative Example 2 The same operation as in Example 1 was performed. However, basis weight 124.5 g / m ²
Using high-quality paper as a sheet-shaped substrate, the wire surface was coated with paint-1 at a solid content of 10 g / m ² , dried and supercalendered to form a backside coating layer with a smoothness of 10,000 seconds. .

In addition, paint-2 is applied to the surface of the base material (felt surface) as a solid content.
An image receiving layer was formed by coating at a rate of 5 g / m ² and drying.

Comparative Example 3 The substrate-1 of Example 1 was used as it was as an image receiving sheet.

[Advantages of the Invention] The image-receiving sheet for thermal transfer printing of the present invention has a feature that it has good dye image receptivity and running property, and that printing and writing are easy on the surface opposite to the image receiving surface. However, it is extremely useful for applications such as postcards and cards.

[Brief description of drawings]

FIG. 1 is a sectional explanatory view showing an example of the constitution of an image receiving sheet for thermal transfer printing of the present invention. 1 ... Sheet-shaped substrate, 2 ... Image receiving layer, 3 ... Backside coating layer.

Continuation of the front page (56) References JP-A-62-158095 (JP, A) JP-A-63-290790 (JP, A) JP-A-1-108083 (JP, A)

Claims (1)

(57) [Claims] 1. A sheet-shaped base material containing a thermoplastic polymer material as a main component, and formed on one surface of the sheet-shaped base material,
And an image receiving layer containing a thermal transfer colorant-receptive polymer material as a main component, and a back surface coating layer formed on the opposite surface of the sheet-shaped substrate, wherein the back surface coating layer is 0.3 μm or less. An average primary particle size,
An average secondary particle size of 1 to 15 μm and a BE of 10 m ² / g or more
An image receiving sheet for thermal transfer printing, comprising a mixture of pigment particles having a T specific surface area and a binder as a main component.