JPS61217289A - Image-receiving paper for thermal transfer paper - Google Patents

Abstract

PURPOSE:To obtain an image-receiving paper free of overflow of an ink, by providing a coated layer comprising as main constituents a nonionic water-soluble high molecular weight compound with a specified low degree of polymerization and a porous pigment with a specified oil absoption. CONSTITUTION:The image-receiving paper used for a thermal transfer paper in combination with a thermal transfer recording sheet provided with a heat- fusible ink layer by coating comprises a coated layer which comprises as main constituents a nonionic water-soluble high molecular weight compound having a low polymerization degree of not higher than 1,000 and a porous pigment with an oil absorption of 30-200ml/100g. It is preferable that the high molecular weight compound is at least one of polyvinyl alcohol, starch, derivatives thereof and cellulose derivatives, while the pigment is at least one of synthetic silica, synthetic zeolite, fired kaolin and calcium carbonate. Accordingly, an image- receiving paper free of overflow of an ink can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application The present invention relates to an image receiving paper for a melt transfer type thermal transfer paper using a thermal head.

(R) Conventional technology The coated surface of thermal transfer paper, which is made of a support sheet and coated with ink layers of the three primary colors of yellow, magenta, and cyan, with a thermofusible substance as the main component, is overlapped with an image receiving paper and applied to a thermal head. Thermal transfer systems that perform heat-melting transfer are now widely used.
Since color recording is obtained by using the three primary colors of ink, the amount of ink transferred is two to three times greater than that of a single color. Therefore, as the ink layer on the image receiving paper becomes the first layer (yellow), the second layer (magenta), and the third layer (cyan), the ink overlap becomes uneven, resulting in uneven images.

In other words, this is called ink bleed, and it has become a major problem. For this reason, improvements have been made to image-receiving paper, thermal transfer paper, and equipment.

For example, there is Japanese Patent Publication No. 59-16950.

This publication describes an ink thermal transfer recording medium in which a water-based paint consisting of a water-soluble nodule agent and a pigment is coated on paper. However, the use of these common materials is still insufficient for full-color printing that requires clear images.

In addition, in Japanese Patent Application Laid-Open No. 57-182487, the oil absorption amount is 30
R//1t containing oil-absorbing pigment of 100# or more! It describes a heat-sensitive recording sheet consisting of layers. Furthermore,
It is described that oil-absorbing pigments are mixed with various binders and applied. However, oil absorption F#30yxl
/1001 or more pigments and binders have mutual suitability and incompetence, and it is difficult to obtain full color with high resolution.

(0) Purpose of the Invention An object of the present invention is to provide an image receiving paper for a melt transfer type thermal transfer paper that does not overflow with ink.

(D) Structure of the Invention As a result of extensive research in view of the above, the present inventors were able to provide an image-receiving paper for a heat-melting transfer type thermal transfer paper that does not overflow ink.

That is, the image receiving paper formed in combination with a thermal transfer recording sheet coated with a heat-melting ink layer is made of a nonionic low-polymerization water-soluble polymer compound with a polymerization number of #1000 or less and an oil absorption amount of 30-30.
This image-receiving paper for thermal transfer paper is characterized in that it is coated with a coating layer mainly composed of a porous pigment of 200 m1/100 fI.

More preferably, the water-soluble polymer compound is a compound selected from at least one of polyvinyl alcohol, starch and derivatives thereof, and in particular, cellulose derivatives, and the porous pigment is at least synthetic silica, synthetic zeolite, etc. This is an image-receiving paper whose main component is a pigment selected from one of the following: , calcined kaolin, and calcium carbonate.

The image-receiving paper is characterized in that the proportion of the water-soluble polymer compound is 1 to 100 parts by weight, preferably 5 to 70 parts by weight, per 100 parts by weight of the pigment.

Next, we will provide a detailed explanation below.

First of all, overflow will be explained in detail.

The thermal transfer system uses three colors: yellow, magenta, and cyan.
The primary colors are printed in order, yellow and magenta create red, yellow and cyan create green, magenta and cyan create purple, and black is created by mixing the three colors ◇For this reason, when using plain paper such as high-quality paper, the surface Since the surface is rough, the contact with the thermal transfer paper is rough, which tends to cause uneven transfer, and furthermore, the color tone of the transferred image is not clear and does not produce the odd-pupil finish characteristic of colors. It is also known to use coated paper as an alternative to plain paper. However, compared to plain paper, pigment-coated image-receiving paper is improved in terms of transfer unevenness and sharpness and darkness of the transferred image, but as mentioned earlier, it is better to use pigment-coated image-receiving paper in two colors and three colors in the order of yellow, magenta, and cyan. As colors are printed, the oil-absorbing ability of the image-receiving paper becomes saturated, causing ink to overflow and eventually resulting in uneven shading.

To improve ink spillage and the clarity of the transferred image, the oil absorption capacity of the ink is controlled by a porous pigment and an adhesive is required to apply the pigment to the base paper.

However, there are a wide variety of these porous pigments and adhesives, and their selection and blending ratio are important.

The image-receiving paper of the present invention is mainly coated with a porous pigment for oil absorption of ink and a water-soluble polymer compound as an adhesive.

Next, specific examples of the porous pigment and adhesive will be given.

Porous pigments with an oil absorption of 30 to 200 ml/IQ 01 include natural or synthetic zeolite, kaolin, calcined kaolin, talc, waxite, canestone,
Examples include synthetic silica, clay, calcium carbonate, magnesium hydroxide, magnesium carbonate, magnesium silicate, titanium oxide, barium carbonate, urea-formalin filler, cellulose filler, aluminum hydroxide, and the like.

Among these, synthetic silica, synthetic zeolite, calcined kaolin, and calcium carbonate are preferred.

Next, examples of the adhesive include nonionic low polymerization degree water-soluble polymers having a polymerization degree of 10'00 or less, such as polyvinyl alcohol, starch and their derivatives, or cellulose derivatives.

Among the above-mentioned nonionic water-soluble polymer compounds, those that have a high degree of polymerization and form a strong film are thought to reduce the oil absorption of the ink. In this sense, according to the present invention, a nonionic water-soluble polymer compound with a low polymerization degree of 1,000 or less is used as an adhesive for image-receiving paper for thermal transfer paper, together with a porous pigment having an oil content of 30 to 200 m//100 Ji'. By forming the image-receiving surface using the above-mentioned ink, it is possible to provide an image-receiving paper that has excellent ink oil absorbency and provides a highly clear transferred image.

Incidentally, other than the above-mentioned water-soluble polymer compounds, for example,
Water-soluble polymers having carboxyl groups, such as anionic ones, are generally considered to be incompatible with non-polar inks. Water-soluble polymer compounds with a high polymerization degree of 100 or more and water-insoluble polymer compounds such as latex and emulsions form a strong film and have poor oil absorption properties for ink.

On the other hand, the oil absorption amount is 30 to 200 = +// 10011 (7
) When a porous pigment is used, in addition to the favorable oil absorption ability of the ink, the transferred image has high definition. If a pigment with a shredded oil absorption amount of 30π//100Ii or less is used, the oil absorption amount of the pigment itself is too small and the ink overflows, rather than the problem of the adhesive film. On the other hand, synthetic silica and white carbon, which have an oil absorption of more than 200ml/10og, have good oil absorption but consume more adhesive than necessary, resulting in problems with adhesive strength.

Next, the blending ratio of the porous pigment and the water-soluble polymer compound will be described. The water-soluble polymer compound is used in an amount of 1 to 100 parts by weight, preferably 5 to 70 parts by weight, per 100 parts by weight of the pigment. That is, if the amount of the water-soluble polymer compound is less than 1 part by weight, the adhesive force of the pigment to the base paper deteriorates, leading to powder falling off from the base paper. If the amount exceeds 100 parts by weight, a film will be formed on the coated surface of the base paper, which may cause ink overflow. Furthermore, it may cause transfer defects, ink peeling, etc.

The base papers used for image-receiving paper include plain paper, coated paper for printing, high-quality paper without pigments, single-gloss paper (for example, dried with a Yankee dryer), synthetic paper, and synthetic resin film. It is coated with

Other additives include pigment dispersants, thickeners, fluidity improvers, antifoaming agents, foam inhibitors, mold release agents, foaming agents, penetrants, colored pigments, colored dyes, fluorescent whitening agents, and ultraviolet light. There is no limitation to the addition of an absorbent, an oxidation preventive agent, a preservative, an anti-spiking agent, etc., as appropriate.

(g) Example The present invention will be explained in more detail by way of examples.

Example 1-1 Plain paper was used as the base paper, and a coating liquid obtained with the following formulation was applied to this paper to obtain an image receiving paper with a dry coating amount of 10 FI/G.0 Pigment: Synthetic silica thyroid manufactured by Fuji Davison Chemical Co., Ltd. 6
5 (oil absorption amount 85ml/100.9) 100 heavy weight adhesive polyvinyl alcohol (polymerization degree 500) 50 heavy weight water 150 commercial weight The evaluation method is Kami, Go Denki color hard copy 0H03
3, superimpose the ink side of the provided thermal transfer paper (manufactured by Boshi Kagaku Paper) on the coated side of the above-mentioned image receiving paper, and apply the three colors of yellow, magenta, and cyan as a single color, two colors, or three colors, respectively. The degree of ink overflow was evaluated by solid printing, and the adhesion of the image-receiving paper was evaluated by applying cellophane adhesive tape manufactured by Nichiban and evaluating the degree of peeling at that time. The results are shown in Table-1.

Table-1 Evaluation Criteria O Overflow even with multiple printing ○ No peeling occurs at all △
Slight overflow due to multiple printing ∆ Partial peeling occurs x Single color printing also overflows x Fully peeling occurs Example 1-2.1-3 and Comparative Example 1-1.1-2 Example 1-
2.1-3 and Comparative Example 1-1.1-2 were prepared in the same manner as in Example 1 except that the oil absorption amount of synthetic silica manufactured by Fuji Davison Chemical was changed as the pigment as shown in Table-1. A receiving paper was obtained and evaluated. The results are shown in Table-1.

Examples 2-1 to 2-4 and Comparative Example 2-1.2-2 Examples 2-1 to 2-4 and Comparative Example 2-1.2-2 are Example 1-
In Example 1, an image receiving paper was obtained and evaluated in the same manner as in Example 1, except that the pigment was changed as shown in Table 2, and the oil absorption amount of the adhesive was changed as shown in Table 1. The results are shown in Table-2.

Table 2 Examples 3-1 to 3-5 and Comparative Examples 3-1 to 3-5 Examples 3-1 to 3-5 and Comparative Examples 3-1 to 3-5 are Example 1-
1, except that the adhesive was changed as shown in Table 3.
A receiver paper was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 3 Table 3 From Tables 1 and 2, it is clear that the oil absorption is 30 to 200.
If a porous pigment outside the range of +//100# is used, the oil absorption of the ink will deteriorate, the adhesiveness will decrease, and the image quality of the image receiving paper will be significantly adversely affected.

In addition, as shown in Table 3, when a nonionic low polymerization degree water-soluble polymer compound with a polymerization degree of 1000 or less and a porous pigment are used, an image receiving paper for thermal transfer paper with strong adhesive strength and good ink oil absorption can be obtained. Obtained.

(P) Effects of the invention By using a nonionic low degree of polymerization water-soluble polymer compound with a polymerization rate of less than yiooo and a porous pigment with an oil absorption of 30 to 200+e7100g, the ink has excellent oil absorption and the transferred image is clear. It is possible to obtain an image-receiving paper for thermal transfer paper with a high temperature, and it is of great industrial significance.

Claims (4)

[Claims] (1) The image receiving paper formed in combination with a thermal transfer recording sheet coated with a heat-melting ink layer is made of a nonionic low polymerization degree water-soluble polymer compound with a polymerization degree of 1000 or less and an oil absorption amount (JIS
An image-receiving paper for thermal transfer paper, characterized in that it is coated with a coating layer mainly composed of a porous pigment having an amount of -K5101) of 30 to 200 ml/100 g. (2) the water-soluble polymer compound is polyvinyl alcohol;
The image-receiving paper for thermal transfer paper according to claim 1, which is a compound selected from at least one of starch and derivatives thereof, and cellulose derivatives. (3) The thermal transfer paper according to claim 1 or 2, wherein the porous pigment is a pigment selected from at least one of synthetic silica, synthetic zeolite, calcined kaolin, and calcium carbonate. Receiving paper. (4) The image-receiving paper for thermal transfer paper according to claim 1, 2, or 3, wherein the water-soluble polymer compound is contained in an amount of 1 to 100 parts by weight based on 100 parts by weight of the porous pigment.