JPH0353985A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To form an image of high quality not lowered in its density even under high temp. environment, having high resolving power and free from background staining by providing a transfer layer containing a specific styrene resin and a styrene/(meth)acrylic ester copolymer resin on a support through a non-transfer layer containing a thermoplastic resin. CONSTITUTION:A non-transfer layer containing a thermoplastic resin and a colorant and a transfer layer containing a heat-meltable substance, a colorant and a styrene resin having a wt. mean MW of 100-30000 and/or a styrene/(meth) acrylic ester copolymer resin are laminated to one surface of a support in this order and 80wt.% or more of the binder resin in the non-transfer layer is a thermoplastic resin. As the thermoplastic resin in the non-transfer layer, a polyester resin, a polyurethane resin, a vinyl chloride resin and an epoxy resin are pref. As the heat-meltable substance of the transfer layer, waxes, higher fatty acid, higher alcohol, amides and higher amines are designated and wax having an m.p. of 50-120 deg.C is pref. The content of the aforementioned heat-meltable substance in the transfer layer is within a range of 30-90wt.% in general.

Description

[Detailed Description of the Invention] [Field of Application in Industry] The present invention relates to a thermal transfer recording medium, and more specifically, the present invention relates to a thermal transfer recording medium, and more particularly, the present invention relates to a thermal transfer recording medium that does not reduce density even in a high-temperature environment such as a facsimile machine that easily accumulates heat. The present invention relates to a thermal transfer recording medium that is capable of forming a high-quality printed image with high resolution and no background smear on a transfer paper having a high surface smoothness, and that also has high confidentiality.

[Prior art and invention or problem to be solved] In recent years, by adopting a thermal transfer recording method for facsimile printing,
Attempts have been made to improve the storage stability of recorded images compared to the thermal coloring method used in conventional facsimile machines, and to enable printing on plain paper.

However, when conventional thermal transfer recording media are used in combination with facsimile line printers, the line heads generally used in line printers do not have sufficient pressing force compared to serial heads. As a result, heat conduction is insufficient, so even if the surface smoothness of the transfer paper used is high, it is difficult to form a high quality printed image.

Furthermore, when a conventional thermal transfer recording medium is used in a high-temperature environment such as a facsimile machine where the power is turned on all day long and heat tends to accumulate, for example, as shown in FIG. Either the ink layer B contains a heat-fusible substance, or the ink layer peels off inside the ink layer B and is transferred to the transfer paper as shown by the broken line in Figure 2. There is a problem that the thickness of the B film becomes thinner and the print density decreases.

Furthermore, in conventional thermal transfer recording media, after the ink layer is transferred to the transfer paper, a so-called self-missing part that corresponds to the shape of the printed image and is readable is generated, which may result in poor confidentiality. be.

Furthermore, in order to improve the quality of printed images generally produced by thermal transfer recording media and obtain clear printed images, high resolution and resistance to scumming are desired.

The present invention has been made based on the above circumstances.

The purpose of the present invention is to form a high-quality printed image with high resolution and no background smearing on transfer paper with a particularly high surface smoothness, without a decrease in density even in a high-temperature environment, and to provide a secret. An object of the present invention is to provide a thermal transfer recording medium with high retention properties.

[A Thousand Steps to Solve the Problem] In order to solve the above problem, the present inventor has made extensive studies, and as a result, a specific non-transfer layer containing a thermoplastic resin in a specific proportion is formed on a support. Surprisingly, in a thermal transfer recording medium provided with a specific transfer layer containing a styrene resin and/or a styrene-(meth)acrylate copolymer resin having a weight average molecular weight within a specific range, Even in high temperature environments, the concentration does not decrease,
In particular, the present invention was achieved by discovering that it is possible to form a high-quality printed image with high resolution and no background smear on a transfer paper with a high surface smoothness, and that it also has high secrecy.

The structure of the present invention is that a non-transfer layer containing a thermoplastic resin and a coloring material is provided on one side of a support, and a heat-melting material and a coloring material each have a weight average molecular weight of 100 to 11.
A transfer layer containing a styrene resin and/or a styrene-(meth)acrylate copolymer resin in the range of 1, ono is laminated in this order, and
80% by weight of the Hinter component in the J+- transfer layer
This is a thermal transfer recording medium characterized by being made of the above-mentioned thermoplastic resin.

Below, regarding the thermal transfer recording medium of the present invention, the support,
The non-transfer layer, the transfer layer, etc. will be explained in detail separately.

Support The support in the thermal transfer recording medium of the present invention preferably has good heat resistance strength and high dimensional stability.

The materials include, for example, papers such as plain paper, condenser paper, laconate paper, and coated paper; resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, and polyimite; composites of paper and resin films; Metal sheets such as aluminum foil are preferably used.

The thickness of the support is usually 30 μm or less, preferably 2 to 30 μm.
It is within the range of 6pm. If the thickness of the support exceeds 3 DILm, thermal conductivity may deteriorate, leading to a decrease in print quality.

In the thermal transfer recording medium of the present invention, the structure on the back side of the support may be arbitrary, and for example, a hacking layer such as a sticking prevention layer may be provided.

Non-transfer layer One of the important points in the present invention is that between the support and the transfer layer, which will be described in detail next, there is a thermoplastic resin containing at least 80% by weight of the binder and a coloring material. The purpose of the present invention is to provide a non-transfer layer.

By providing this non-transfer layer, in the thermal transfer recording medium of the present invention, when the transfer layer is peeled off from the support side as detailed below, the transfer layer can be reliably peeled off at the interface of the non-transfer layer even in a high temperature environment. This makes it possible to produce a high-density, clear printed image.

In addition, the non-transfer layer remains on the support even after the transfer waste is transferred to the transfer medium, and since it contains a coloring material, it prevents the occurrence of the so-called white areas described above, and can be used in the present invention. To improve the confidentiality of a thermal transfer recording medium.

Such action or function of the non-transfer layer is mainly brought about by the thermoplastic resin and the coloring material contained in the non-transfer layer.

Examples of the thermoplastic resin in the non-transfer layer include polyamide resins, polyester resins, polyurethane resins, polyolefin resins, acrylic resins, vinyl chloride resins, cellulose resins, epoxy resins, rosin resins, Examples include vinyl acetate resins, cellulose resins, ionomer resins, polyacetals, polycarbonates, polyphenylene oxides, and noryl resins, borisulfones, fluorine resins, and silicone resins.

Among these, preferred are polyester resins, polyurethane resins, epoxy resins, and vinyl chloride resins.

The thermoplastic resins may be used alone or in combination of two or more.

In any case, in the present invention, it is necessary that the thermoplastic resin accounts for 80% by weight or more of the binder component in the non-transfer layer.

The non-transfer layer contains the coloring material together with the thermoplastic resin.

The coloring material has the function of preventing the formation of the so-called white areas after being transferred from the transfer layer to the transfer medium.

Therefore, the color of the coloring material contained in the non-transfer layer is preferably the same as the color of the coloring material in the transfer layer, which will be described in detail below.

As the coloring material, the same coloring material as the coloring material in the transfer layer, which will be described in detail below, can be suitably used.

The content of the coloring material in the non-transfer layer is usually 60% by weight or less, preferably 10 to 50% by weight.

The non-transfer layer may contain a heat-fusible substance together with the thermoplastic resin and the coloring material.

As the heat-fusible substance, the same heat-fusible substance as that which can be contained in the transfer layer described in detail below can be suitably used.

When the non-transfer layer contains the heat-fusible substance, the content of the heat-fusible substance is usually 50% by weight or less, preferably 30% by weight or less.

The non-transfer layer containing the above-mentioned components can be coated on the support by, for example, a blood coating method such as an aqueous coating method, a coating method using an organic solvent, or a photomelt coating method.

The layer thickness of the non-transfer layer is usually within the range of 0.3 to 3 #Lm, preferably within the range of 0.2 to 2 #Lm. By setting this layer thickness within the above range, the object of the present invention can be fully achieved.

A transfer layer, which will be described next, is laminated on and adjacent to this non-transfer layer.

Transfer layer The transfer layer consists of a heat-fusible substance, a coloring material, and a weight average molecular weight of 1.
It contains a styrene resin and/or a styrene-(meth)acrylic acid ester copolymer resin in the range of 000 to 10,000.

The heat-melting substances include, for example, vegetable waxes such as carnauba wax, wood wax, auriculie wax, and esbal wax; animal waxes such as beeswax, insect wax, shellac wax, and spermaceti wax; paraffin wax, microcrystalline wax, polyethylene wax, and esters. Mention may be made of waxes such as petroleum waxes such as waxes and acid waxes; and mineral waxes such as montan wax, ozokerite and ceresin; besides these waxes, palmitic acid, stearic acid, margaric acid and Higher fatty acids such as henic acid; Higher alcohols such as palmityl alcohol, stearyl alcohol, behenyl alcohol, marganyl alcohol, myricyl alcohol, and eicosanol: cetyl palmitate, myricyl valmitate, cetyl stearate, myricyl stearate, etc. higher fatty acid esters: Amites such as acetamite, propionic acid amide 1 to amide valmitate, amide stearate and amitowax; and higher amines such as stearylamine, behenylamine and valmitylamine.

These may be used alone or in combination of two or more.

Among these, preferred is a wax whose melting point is within the range of 5D to 120°C as measured using a Yanagiki MJP-2 model.

The content of the heat-fusible substance in the transfer layer is usually 3
The coloring material, which is preferably in the range of 0 to 90% by weight, may include, for example, pigments such as inorganic pigments and organic pigments, and dyes.

The inorganic pigments include titanium dioxide, carbon black, zinc oxide, Prussian flu, cadmium sulfide,
Examples include iron oxides and chromates of lead, zinc, barium and calcium.

Examples of the organic pigments include azo, thioinsigo, anthraquinone, anthurone, and triphendioxacin pigments, hat dye pigments, butalocyanine pigments, such as copper phthalocyanine and its derivatives, and quinacridone pigments.

Examples of the organic dye include acid dyes, direct dyes, disperse dyes, oil-soluble dyes, and metal-containing oil-soluble dyes.

Among these various coloring materials, carbon turac is particularly preferred.

The content of the coloring material in the transfer layer is usually in the range of 5 to 30% by weight, preferably in the range of 10 to 25% by weight.

One of the important points in the present invention is that the transfer layer is made of styrene resin and/or styrene having a weight average molecular weight (M,) in the range of 100 to 30,000, together with the heat-fusible substance and the coloring material. (meth)acrylic acid ester copolymer resin. Containing this specific resin in the transfer layer is important in order to form a high quality printed image without a decrease in density even in a high temperature environment.

That is, the transfer layer is made of the above-mentioned specific styrene resin and/or
Alternatively, by containing a styrene-(meth)acrylate copolymer resin, the releasability of the transfer layer at the interface with the non-transfer layer and the fixability of the transfer layer to the transfer medium are improved.

However, in order to sufficiently exhibit such desired effects, the weight average molecular weight (Mw) of the styrene resin or the styrene-(meth)acrylic acid ester copolymer resin must be adjusted.
ranges from 100 to 30,000, preferably from 300 to
It needs to be in the range of 10,000.

Moreover, the softening point of the styrene resin or the styrene (meth)acrylic acid ester copolymer resin is in the range of 50 to 140°C, preferably 60 to 1206°C, as measured using a descending flow tester. If this softening point falls outside of the above range, the transfer layer may not have sufficient fixing properties to the transfer medium, or may not peel off at the interface between the transfer layer and the non-transfer layer.

The content of the styrene resin and/or (meth)acrylic acid ester copolymer resin in the transfer layer is usually 1
-60% by weight, preferably 2-50% by weight.

It is preferable that the transfer layer further contains a tackifier in addition to the heat-melting substance, the coloring material, and the styrene resin and/or (meth)acrylic acid ester copolymer resin. When the tackifier is contained, the adhesion of the transfer layer to the transfer medium is improved.

The adhesive agent used in the present invention is a hydrocarbon compound having a polar group such as a hydroxyl group or a carboxyl group, and exhibits adhesive strength when used alone or in combination with other components. There is a substance.

Such tackifying agents include, for example, rosin tackifiers, water-added rosin tackifiers, rosin maleic acid tackifiers, polymerized rosin tackifiers, and rosin phenol lees adhesion agents. Examples include unmodified or modified rosin-based tackifiers, terbene-based tackifiers, stone sleeve resin-based tackifiers, and modified tackifiers thereof.

When using the tackifier, the content of the tackifier in the transfer layer is usually 1 to 60% by weight, preferably 2 to 50% by weight.

Further, the transfer layer may contain, in addition to the above-mentioned components, a surfactant such as a boroxyethylene chain-containing compound.

The transfer layer may further contain inorganic or organic fine particles (metal powder, silica gel, etc.), oil particles (linseed oil, mineral oil, etc.).

The transfer layer can be coated on the non-transfer layer by employing a coating method such as a water-based coating method or a coating method using an organic solvent.

The layer thickness of this transfer layer is usually within the range of 1 to 10 ILm, preferably within the range of 2 to 61 Lm.

In addition, the thermal transfer recording medium of the present invention usually includes, on the support,
After coating the non-transfer layer and the transfer layer in this order, the film can be manufactured by performing a drying process, a surface smoothing process, etc., if desired, and then cutting into a desired shape.

The thermal transfer recording medium obtained in this way can be used in the form of a wide tape or typewriter ribbon generally used in line printers, etc., or can be used in the planar shape of the thermal transfer recording medium of the present invention. A sheet having substantially the same width as the recording paper used in line printers is preferable.

The thermal transfer method using the thermal transfer recording medium of the present invention is different from a normal thermal transfer recording method, and will be explained by taking as an example the case where the most typical thermal head is used as the heat source.

First, the transfer layer of a thermal transfer recording medium and a transfer medium such as plain paper are brought into close contact with each other, and a heat pulse is applied using a thermal head to locally apply a heat-softening coloring material layer corresponding to a desired print or transfer pattern. heat it up.

The temperature of the heated portion of the transfer layer increases, for example,
As shown in Figure (a), the transfer layer 1 quickly softens,
It is peeled off from the interface with the non-transfer layer 2 and transferred onto the transfer medium. After the transfer layer 1 has been transferred, the non-transfer layer 2 remains on the support 3, as shown in FIG. 1(b).

[Example] Next, Examples and Comparative Examples of the present invention will be shown to further specifically explain the present invention.

(Example 1) The following non-transfer layer set J & material was placed on a polyethylene terephthalate film with a thickness of 4.5 gm using a wire harness so that the thickness was 107 zm over a length corresponding to the width of JIS standard A4 paper. It was coated by a solvent coating method to form a non-transfer layer in the thermal transfer recording medium of the present invention.

Renkeido 4-layer bottle i-Koji polyester resin...80% by weight [Hiron 200 J. Manufactured by Toyobo ■] Carbon trac...
...20% by weight Next, a transfer layer was formed by applying the following transfer layer composition to a layer thickness of 4 gm on the non-transfer layer by a hot melt coating method using a Clavia roll, A thermal transfer recording medium of the present invention was obtained.

Styrene resin (weight average molecular weight Mv-1,000) Paraffin wax Carbon flak Carbon flak 10% by weight 70% by weight ・20% by weight The obtained thermal transfer recording medium was transferred to a thermal printer (26% by weight).
01IIIl width line head, 18G DPI. The results were recorded (printed) on highly smooth paper (Beck smoothness: 100 seconds) using a Braten rubber hardness of 40 degrees, and the density reduction, resolution, scumming, and confidentiality of the printed image were evaluated.

The results are shown in Table 1.

Note that the density and resolution of printed images may decrease. Background staining and confidentiality were evaluated as follows.

Decrease in density: Printing was performed at a printer internal temperature of 40°C, and the print reflection density was evaluated in the following two grades.

0: Print reflection density 1.4 or more.

×: Print reflection density less than 1.4.

Resolution: The reproducibility of the 1-tot crease line was visually evaluated in the following two grades.

O: Uninterrupted.

×: There are gaps.

Background smudge: The smudge at the beginning of the print was visually observed and rated on the following two scales: l 9 .

○: No stains at the beginning of printing.

×: Dirt occurs at the beginning of printing.

Confidentiality: Visual observation was performed using reflected light for blanks after printing.

○: No missing parts after printing.

△: Some parts are missing.

(Example 2) In Example 1, the procedure was carried out in the same manner as in Example 1, except that the following transfer layer composition was used in place of the transfer layer composition used in Example 1. .

The results are shown in Table 1.

1104 Koji Styrene-acrylic acid ester copolymer resin... (Weight average molecular weight Mv-5,000) Paraffin wax... 20 ・15% by weight ・65% by weight Carbon Turac... ...20% by weight (Comparative Example 1) In Example 1, the following transfer layer composition was used in place of the transfer layer composition used in Example 1. In the same manner as in Example 1, a non-transfer layer,
A heat-sensitive transfer recording medium was manufactured by laminating transfer layers in this order, and this heat-sensitive transfer recording medium was evaluated.

The results are shown in Table 1.

Ai 1'mu1 Koji Ethylene-vinyl acetate copolymer...lO wt% (vinyl acetate content 28 wt%) Paraffin wax...70 wt% Carbon flak... 20% by weight (Comparative Example 2) In the same manner as in Example 1, except that the following transfer layer composition was used in place of the transfer layer composition used in Example 1, A thermal transfer recording medium was manufactured by laminating a non-transfer layer and a transfer layer in this order on a support, and this thermal transfer recording medium was evaluated.

The results are shown in Table 1.

1'' Kashi Naoko Koji Paraffin wax...80% by weight Carbon black... 20% by weight (This page, blank space below) Chapter ■ Table 23 (Evaluation) From Table 1 As is clear, the thermal transfer recording medium of the present invention does not reduce density even in high-temperature environments, has high resolution, does not cause background smearing, and forms high-quality printed images with excellent confidentiality. I confirmed that it is possible.

[Effects of the Invention] According to the present invention, (1) the non-transfer layer laminated on the support is 80% by weight or more of the binder component or a thermoplastic resin;
The transfer layer laminated on the non-transfer layer is made of styrene resin and/or styrene resin having a weight average molecular weight within a specific range.
Contains meth)acrylic acid ester copolymer resin,
For example, even in high-temperature environments such as line printers of facsimile machines, the transfer layer always peels off stably at the interface between the transfer layer and the non-transfer layer, so there is no decrease in density, and the transfer layer is only sticky, resulting in a high-temperature coating that does not cause scumming. (2) After the transfer layer is transferred to the transfer medium L, the non-transfer layer remaining on the support 2 contains the coloring material. , there is no legible so-called omission part,
It is possible to provide a high-performance thermal transfer recording medium that has various advantages such as high confidentiality, (3) security, and high resolution.

[Brief explanation of drawings]

1(a) and 1(b) are cross-sectional explanatory diagrams showing the relationship between the transfer layer and the non-transfer layer in the thermal transfer recording medium of the present invention, respectively, and FIG. 2 is an example of a conventional thermal transfer recording medium. FIG. l... Transfer layer, 2... Non-transfer layer, 3... Support

Claims (1)

[Claims] (1) On one side of the support, a non-transfer layer containing a thermoplastic resin and a coloring material, and a styrene layer having a weight average molecular weight in the range of 100 to 30,000 together with a heat-melting material and a coloring material. A transfer layer containing a resin and/or a styrene-(meth)acrylate copolymer resin is laminated in this order, and 80% by weight or more of the binder component in the non-transfer layer is the thermoplastic resin. A thermal transfer recording medium characterized by: