JPH05155153A - Thermal transfer image-receiving sheet - Google Patents

Abstract

PURPOSE:To obtain a thermal transfer image-receiving sheet having excellent thermal transfer printer aptitude and being available even as a card base material, etc., by forming the image forming surface of the sheet in specific smoothness in the transparent or white thermal transfer image-receiving sheet using polyvinyl chloride as a main agent. CONSTITUTION:In a transparent or white thermal transfer image-receiving sheet 1 employing polyvinyl chloride as a main agent, the Bekk smoothness of the image 4 forming surface is set to 100sec or more. The hue of the white thermal transfer image-receiving sheet 1 is kept within a range of 85<L*, -3<a*<5 and -5<b*<+2. The haze value of the transparent thermal transfer image-receiving sheet is set to 50 or less. The rear surface has irregularities in depths of 2-30mum. It is favorable that antistatic treatment is executed on at least one surface and a detection mark required at the time of printing is formed. Accordingly, the thermal transfer image-receiving sheet having excellent thermal transfer printer aptitude and being available even as a card base material, etc., can be acquired.

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, and more particularly to a thermal transfer image receiving sheet which can easily form a complicated image such as a facial photograph by a sublimation transfer method and is useful as a card substrate.

[0002]

2. Description of the Related Art Conventionally, many cards such as an identification card, a driver's license, a membership card, etc. have been used, and various kinds of information for clarifying the owner's identity etc. are recorded on these cards.
Especially for ID cards and the like, facial photographs are the most important.

[0003]

[Problems to be Solved by the Invention] A classical method of giving a face photograph to various cards is a method of attaching the face photograph to a predetermined portion of the card base material using an adhesive.
This method has the drawback that its operation is very complicated and that the surface of the card becomes uneven and the smoothness is lost. An image forming method using a sublimation transfer method has been developed as a method for solving the above-mentioned drawbacks of the face photograph sticking method. In this sublimation transfer method, a sublimation transfer sheet in which a layer containing a dye that is sublimated and transferred by heat is provided on the surface of a substrate film is superposed on a card substrate, and the card substrate is heated from the back of the sublimation transfer sheet by a thermal head. It is a method of reproducing a facial photograph on a material, and has an advantage that it can be performed by a simple thermal transfer printer. However, when the above-mentioned sublimation transfer method is used, the card substrate is required to have sufficient dyeing property to the sublimable dye, and the present inventor has previously been excellent in dyeing property. Proposed a card substrate made of vinyl chloride resin (see Japanese Patent Application No. 63-226428).

However, in the case of the above card substrate, the suitability for a thermal transfer printer is still insufficient, and various problems occur, for example, when the card substrate is a laminated substrate,
The hardness of the base material is high, and there is a restriction that an end surface type thermal head must be used in an apparatus for forming an image. That is, there is a problem that it is difficult to form an image with a commercially available video printer and an excellent image cannot be formed. Therefore, an object of the present invention is to provide a thermal transfer image-receiving sheet which is excellent in suitability for a thermal transfer printer and is also useful as a card substrate or the like.

[0005]

The above object can be achieved by the present invention described below. That is, the present invention provides a transparent or white thermal transfer image-receiving sheet containing polyvinyl chloride as a main component, wherein the Beck smoothness of the image forming surface is 100 seconds or more.

[0006]

When a polyvinyl chloride sheet is used as the main component of the card base material and the Bekk smoothness of the image forming surface is 100 seconds or more, the thermal transfer printer suitability becomes good, and for example, the low gradation part of the formed image is obtained. From the to the high gradation part, an excellent image is formed without missing dots, missing dots, or roughness.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. The polyvinyl chloride resins used in the present invention are known per se, and card substrates molded from these polyvinyl chloride resins are also known. These conventionally known polyvinyl chloride card base materials are formed of so-called hard polyvinyl chloride resin containing almost no plasticizer. On the other hand, in the present invention, when a card substrate is prepared from polyvinyl chloride according to a conventional method, 0.1% of polyvinyl chloride is added to 100% by weight of polyvinyl chloride.
By forming the card base material with 10 parts by weight of the plasticizer included, the card base material has sufficient dyeability to the sublimable dye. Examples of the plasticizer used in the present invention include dibutyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, dilauryl phthalate, butyl lauryl phthalate,
Butylbenzyl phthalate, di (2-ethylhexyl) adipate, di (2-ethylhexyl) sebacate, tricresyl phosphate, tri (2-ethylhexyl) phosphate,
Any conventionally known plasticizer such as polyethylene glycol ester and epoxy fatty acid ester can be used.

The amount of these plasticizers used is 0.1 to 10 parts by weight per 100 parts by weight of polyvinyl chloride, and a particularly preferred range is 3 to 5 parts by weight. If the amount of plasticizer used is too small, the dyeability to the sublimable dye is insufficient,
On the other hand, if the amount is too large, the rigidity of the card substrate is insufficient and the card substrate becomes soft, and the printed image is bleeding during sublimation transfer, and a clear image cannot be obtained, which is not preferable. Further, in a preferred embodiment of the present invention, in addition to the above-mentioned plasticizer, by further including 0.1 to 5 parts by weight of a lubricant per 100 parts by weight of polyvinyl chloride, a relatively large amount of the plasticizer, for example, 5 ~ 1
Even when it is contained in polyvinyl chloride in an amount of 0 parts by weight, the thermal transfer sheet is not blocked at the time of transfer, and the dyeability of the resulting card substrate with the sublimable dye is further improved.

As such a lubricant, any conventionally known lubricant such as fatty acid, fatty acid amide, wax and paraffin can be used. If the amount of these lubricants used is too small, the effect due to the addition will not be obtained, and if the amount is too large, the surface of the obtained card substrate will be roughened, which is not preferable. or,
By using these lubricants, not only the dyeability of the sublimable dye is improved, but even when a relatively high temperature is used during the sublimation transfer, the adhesion between the sublimation transfer sheet and the card substrate is reduced, and the higher concentration is achieved. Image can be formed more efficiently. The main components of the thermal transfer image-receiving sheet of the present invention are as described above. When the thermal transfer image-receiving sheet is an opaque white type, white pigment, extender pigment, filler, ultraviolet absorber, antistatic agent, heat stabilizer are further added. , An antioxidant, a fluorescent whitening agent and the like can be optionally used, and when the thermal transfer image-receiving sheet is a transparent type, various additives other than the white pigment can be included.

The thermal transfer image-receiving sheet of the present invention is prepared by blending the necessary components as described above, and blending the blend by a well-known forming method such as calendering or extrusion.
In the case of white opaque type, it is in the form of a sheet with a thickness of 0.05 to 0.5 mm, and in the case of a transparent type 0.05 to 0.5 mm.
The present invention includes both a sheet obtained by molding to a moderate thickness and cut into a so-called card size and a sheet cut into a card size. With such a thickness, the sheet is excellent in flexibility, so that it is in good contact with the platen of the printer at the time of printing, and no dot breakage or dropout occurs. The thermal transfer image-receiving sheet of the present invention may be a transparent type or a white type, and either side may be the image forming side,
It is necessary that the image forming surface has a Bekk smoothness of 100 seconds or more. If the Beck's smoothness is less than 100 seconds, there are disadvantages such as dot dropouts and chippings in the formed image, and image roughness. A known smoothing method such as a calendering method may be adopted as the method for setting the Beck smoothness to 100 seconds or more.

Further, in the case of the white opaque type, the hue thereof is 85 <L ^* , -3 <a ^* <5 and -5 <b ^* <+ 2.
Is preferably in the range of, and if it is outside this range,
Image quality is poor due to the hue and lightness of the printed image,
For example, if the image to be formed is a face photo of a certificate,
I am not satisfied in terms of collation with the person. To adjust the whiteness to the above range, a method of kneading a dye, a pigment, a fluorescent whitening agent and the like in an appropriate amount at the time of forming the sheet may be adopted.
On the other hand, in the case of the transparent type, the haze value is 50 or less, preferably 30 or less. When the haze value exceeds 50, it is unsatisfactory in that the pattern of the tint block or the like preprinted on the base material such as the card substrate is not clear. In order to set the haze value to 50 or less, it is possible to use a method of controlling the amount of additives, such as various fillers, which are kneaded when the sheet is formed.

Further, in any type of thermal transfer image receiving sheet, it is preferable that the back surface opposite to the image forming surface has an uneven shape, and the uneven depth is 2 to 30 μm.
In this case, there is an advantage that the conveyance suitability of the image receiving sheet in the printer at the time of printing, the press suitability at the time of bonding, and the like are improved. Furthermore, in the present invention, at least one surface of the thermal transfer image-receiving sheet is subjected to antistatic treatment,
It is preferable to provide a detection mark necessary for printing. A method for making a card using the thermal transfer image-receiving sheet of the present invention will be described below. FIG. 1a is a cross section of the transparent type thermal transfer image receiving sheet of the present invention. As shown in FIG. 1b, a dye layer of a known sublimation transfer sheet 2 is superposed on the surface of the thermal transfer image receiving sheet 1 so as to face the sublimation transfer sheet 2. A desired image 4 is formed on the surface of the thermal transfer image-receiving sheet 1 by heating from the back surface with the thermal head 3 or the like. Of course, such a thermal transfer image-receiving sheet 1 may be preliminarily formed with a necessary embossed pattern or other printed pattern on its surface,
Also, these embossments and printed patterns may be provided after sublimation transfer. Then, if necessary, the above-mentioned image-formed thermal transfer image-receiving sheet is thermocompression-bonded to the surface of the white vinyl chloride resin sheet 5 serving as the core of the card, preferably with the image surface inside, and in some cases, a transparent resin on the back surface. A sheet (which may be the transparent thermal transfer image-receiving sheet of the present invention) is thermocompression bonded, and finally cut into a card size.

The example of FIG. 2 shows an example of making a card using the opaque thermal transfer image-receiving sheet of the present invention.
a is a cross section of the white opaque thermal transfer image-receiving sheet of the present invention. As shown in FIG. 2b, the dye layer of the known sublimation transfer sheet 2 is superposed on the surface of the thermal transfer image-receiving sheet 1 so as to face the back surface of the sublimation transfer sheet 2. Then, the desired image 4 is formed on the surface of the thermal transfer image-receiving sheet 1 by heating with the thermal head 3 or the like. Needless to say, such a thermal transfer image-receiving sheet 1 may be preliminarily formed with a necessary embossing pattern or other printing pattern on its surface, or may be provided with these embossing or printing pattern after sublimation transfer. .. Then, if necessary, a transparent resin sheet 5 (which may be the transparent type thermal transfer image-receiving sheet of the present invention) serving as the surface material of the card is laminated, and a card is produced in the same manner as in the case of FIG. 1 below. Although the characteristic part of the present invention has been described above, the thermal transfer image-receiving sheet of the present invention is not limited to a card substrate and is also useful for various other uses.

[0014]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, unless otherwise specified, “parts” and “%” in the text are based on weight. Example 1 On the surface of a transparent vinyl chloride resin sheet (plasticizer 5 phr, surface smoothness 280 sec, haze value 15) (Mitsubishi resin made vinyl foil C-8133, thickness 0.15 mm) provided with irregularities having a depth of 10 μm on the back surface. , The antistatic agent Statiside 0.
A 2% isopropyl alcohol solution was applied, a detection mark was printed at a predetermined position on the back surface, and cut into a predetermined size.
Using this as a thermal transfer image-receiving sheet, a full-color image was formed by a video printer (HI's VY-P1).
A very good image was formed with excellent gloss and no missing or missing dots. Next, a polyvinyl chloride (polymerization degree 800) compound 100 containing about 10% of additives such as stabilizers.
Part and white pigment (titanium oxide) 15 parts by composition of white card base core (thickness 0.2 mm, size 30 × 30
cm) on one side of the base material core, the sheet on which the above-mentioned image is formed with the image side inside, and the same transparent vinyl chloride sheet before the image is formed on the other side Then, a card as shown in FIG. 1 was obtained.

Example 2 White vinyl chloride resin sheet (15 plastics of plasticizer, surface smoothness of 350 seconds, hue L
^* : 94, a ^* : 1.6, b ^* : -1.5) (Mitsubishi resin vinyl foil C-726, thickness 0.15 mm) A detection mark is printed at a predetermined position on the back surface and cut into a predetermined size. did. This is used as a thermal transfer image receiving sheet for a video printer (H
When a full-color image was formed using VY-P1) manufactured by I, a very good image was formed with excellent gloss and no missing or missing dots. The transparent vinyl chloride sheet of Example 1 was thermocompression bonded to both sides of this image to prepare a card as shown in FIG.

Comparative Example 1 A sheet having the same composition as Example 1 but having the same composition but a Beck smoothness of the image forming surface of 60 seconds was used to form a similar image. However, there were dots missing or missing, and only a rough image was formed.

[Effects] According to the present invention as described above, by using a polyvinyl chloride sheet as the main component of the card substrate and setting the Bekk smoothness of the image forming surface to 100 seconds or more, the suitability for a thermal transfer printer becomes good, For example, an excellent image having no missing dots, missing dots, or roughness is formed from the low gradation part to the high gradation part of the formed image.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a cross section of a thermal transfer image receiving sheet of the present invention and manufacturing of a card.

FIG. 2 is a diagram schematically illustrating a cross section of a thermal transfer image-receiving sheet of the present invention and manufacturing of a card.

[Explanation of symbols]

 1: Thermal transfer image receiving sheet 2: Thermal transfer film 3: Thermal head 4: Image

Claims (6)

[Claims] 1. A transparent or white thermal transfer image-receiving sheet containing polyvinyl chloride as a main component, wherein the Bekk smoothness of the image forming surface is 100 seconds or more. 2. The hue of the white heat transfer image-receiving sheet is 85 <
The thermal transfer image-receiving sheet according to claim 1, which is in the range of L ^* , -3 <a ^* <5 and -5 <b ^* <+ 2. 3. A transparent thermal transfer image-receiving sheet having a haze value of 5
The thermal transfer image-receiving sheet according to claim 1, which is 0 or less. 4. The thermal transfer image-receiving sheet according to claim 1, wherein the back surface has irregularities having a depth of 2 to 30 μm. 5. The thermal transfer image-receiving sheet according to claim 1, wherein at least one surface thereof is subjected to antistatic treatment. 6. The thermal transfer image-receiving sheet according to claim 1, wherein a detection mark is provided on at least one surface.