JPH0259797B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a thermal transfer recording medium that can be used multiple times. Specifically, if the applied energy is above a certain level, a transferred image with a constant transfer density can be obtained, and it is possible to obtain a constant print quality over many times without being affected by subtle changes in the applied energy. The present invention relates to thermal transfer recording media. [Prior Art] As a thermal transfer recording medium intended for multiple uses, for example, Japanese Patent Laid-Open No. 55-105579 discloses a technique in which a microporous layer is formed with a resin and the layer is impregnated with ink. is described, and also published in Japanese Unexamined Patent Publication in 1983
Japanese Patent Publication No. 160691 describes a technique for forming a network structure using organic or inorganic fine powder and impregnating it with ink, and Japanese Patent Application Laid-open No. 185192-1987 describes a technique for impregnating ink into porous paper. A technique for impregnation is described. All of these technologies were designed to allow the ink to seep out little by little from the porous material, but in these technologies the transfer density changes in response to subtle changes in the applied energy, resulting in a constant print quality. The problem is that it cannot be obtained. [Problems to be Solved by the Invention] According to the present invention, a transferred image with a constant transfer density can be obtained if the applied energy is above a certain level, and
A technical problem is to provide a thermal transfer recording medium that can obtain constant printing quality over a large number of times without being affected by subtle changes in applied energy. [Means for Solving the Problems] As a result of intensive research, the present inventors have discovered that, in a thermal transfer recording medium having a heat-fusible coloring material layer on a support, the coloring material layer is a multilayer of two or more layers. It is composed of
One layer of the coloring material layer contains at least one heat-melting substance selected from the following compound group, and the coloring material layer adjacent to the coloring material layer is heat-melting and immiscible with the heat-melting substance. It has been found that the above technical problem can be solved by containing at least one heat-melting substance selected from the following compound group, and the present invention has been achieved. [Compound Group] Animal-based waxes Plant-based waxes Mineral-based waxes Petroleum-based waxes Synthetic hydrocarbon-based waxes Modified waxes In the multilayer thermal transfer recording medium, one coloring material layer contains at least one heat-melting material selected from the above compound group. At least one coloring material layer containing a substance and adjacent to the one coloring material layer is selected from a heat-melting substance immiscible with the heat-melting material contained in the one coloring material layer and the above compound group. However, it is within the technical scope of the present invention if it contains at least one kind of heat-fusible substance, but between adjacent coloring material layers,
It is preferable that all of the above conditions of the present invention be satisfied. Note that in the present invention, adjacent coloring material layers are not limited to directly adjacent layers, but also include cases where they are indirectly adjacent via a layer other than the coloring material layer. The present invention will be explained in more detail below. The thermal transfer recording medium of the present invention has a heat-melting coloring material layer provided on a support. This heat-melting coloring material layer is preferably applied to two layers on the support via an adhesive layer.
Formed in multiple layers. The heat-melting coloring material layer referred to in the present invention is a layer that is melted by energy applied by a thermal head or the like and transferred to the transfer paper side.
A layer that can obtain printing with the required transfer density in one transfer. In the present invention, a preferred layer structure is, for example, sequentially coating a coloring material layer and a coloring material layer on a support,
The coloring material layer contains at least one so-called low-polarity heat-melting substance selected from the compound group, and the coloring material layer contains a heat-melting substance immiscible with the heat-melting substance (so-called high polarity). A multilayer structure containing a thermofusible substance and at least one thermofusible substance selected from the above-mentioned group of compounds can be mentioned. With such a configuration, the coloring material layer has immiscibility with the coloring material layer. The present invention utilizes the reduction in breaking strength (releasability between coloring material layers) based on this immiscibility. That is, in the process of applying energy to melt the coloring material layer and transferring (peeling off) it to the transfer paper side, the coloring material layer is peeled off near the boundary between the coloring material layers. This results in 1
One coloring material layer is transferred in one transfer. In the case of the above layer structure, two transfers are possible, but
Furthermore, in order to increase the number of transfers, overlapping layers such as a coloring material layer, a coloring material layer, a coloring material layer, and a coloring material layer, each of which is immiscible with each other, can be laminated on top of the coloring material layer. . In this case, the coloring material layer,
, may have the same composition or may have different compositions. Similarly, the coloring material layers may have the same composition or may have different compositions. In the present invention, it is preferable that the coloring material layer containing at least one kind of heat-melting substance selected from the above-mentioned group of compounds does not contain a heat-melting substance that is substantially immiscible therewith, and even if it contains, The content is preferably 10% by weight or less based on the total weight of this coloring material layer. The above compound group used in the present invention includes waxes that have relatively low polarity and are solid at room temperature, preferably with a melting point (JIS K
2523) or softening point (Ring and Ball method JIS K 2207)
Examples include waxes having a temperature of 40 to 90°C, and specifically the waxes listed below are used. Animal-based waxes include beeswax, insect wax,
Examples include seratsukuro, whale wax, wool wax, etc.
Examples of plant-based waxes include carnauba wax, wood wax, auricilla wax, esparto wax, and chianderilla wax; examples of mineral-based waxes include montan wax, ozokerite, and ceresin; and examples of petroleum-based waxes include paraffin wax, Examples of synthetic hydrocarbon waxes include fiberglass waxes, polyethylene waxes, low molecular weight polypropylene, low molecular weight polyethylene and derivatives thereof, and modified As wax,
Examples include oxidized wax, montan wax derivatives, paraffin or micro wax derivatives. These may be used alone or in combination of two or more. In the present invention, hydrogenated waxes such as castor wax and opal wax can also be used. In the present invention, the heat-fusible substance that is immiscible with the above compound group is preferably a heat-fusible substance that is highly polar and immiscible with respect to the above-mentioned wax, which has relatively low polarity. In the present invention, immiscibility means that when both are mixed by thermal melting or softening, they exhibit a cloudy state, an oil droplet shape, a layer separation, or an incompatible state, which may be detected from the appearance, but is not necessarily detected. You don't have to be able to do it. As one method of expressing polarity, the solubility parameter δ can be used, and the solubility parameter of the highly polar heat-fusible substance in the present invention is preferably δ≧9.5, more preferably δ≧10.0. The solubility parameter of waxes with relatively low polarity shown in the above compound group is expressed as δ≦9.0. Heat-fusible substances that are immiscible with the above compound group include substances whose main chain is not simply composed of carbon-carbon bonds, such as vinyl polymers, but whose main chain contains bonds that impart polarity. Synthetic polymer compounds are preferred. Typical compounds include polyester compounds, polyether compounds, polyamide compounds, and polyurethane compounds. Among these, those that are solid at room temperature (25℃),
For example, a substance having a melting point (mp) or softening point of 35 to 100°C is preferable, and more preferably a substance having a relatively low melting point or softening point of 45 to 85°C is used. In addition, in consideration of breaking strength, the molecular weight is preferably low, and specifically, it is preferably 500 or more and 50,000 or less, more preferably 1,000 or more and 15,000 or less. Specific examples include the following compounds. (1) Polyester compounds Preferred polyester compounds have −
It is a linear polyester having a CO-O- bond and solid at room temperature (25°C) and its derivatives, and includes polycarbonate and unsaturated polyester having a -CO-O- bond in the main chain. These polyesters are synthesized as polycondensates of polyhydric alcohols and polybasic acids or ring-opened polymers of lactams. When the polyester derivative is a copolymer, a block copolymer or a graft copolymer is preferable, and it is preferable that the polyester derivative has a large number of ester bonding moieties. Specific examples include ester compounds such as polyethylene glycol fatty acid ester, polyethylene glycol sorbitan fatty acid ester, polyoxyethylene lanolin fatty acid ester, and block copolymers synthesized from polyethylene glycol and ε-caprolactone. For example, a polyester compound produced by polymerizing a compound having an alcoholic OH group and ε-caprolactone by the reaction described below can also be obtained as a commercial product. Commercial product name: “Placcel G-402”, “Placcel
240”, “Placcel 260”, “Placcel 280”,
"Placcel H-1" etc. (manufactured by Daicel Chemical Co., Ltd.) (2) Polyether compounds Preferred polyether compounds have -
It is a compound that is solid at room temperature (25°C) and has a [C-O-C]- bond, and also includes polyethylene oxide, epoxy resin, etc. that have an -O- bond in the main chain. The above polyether compounds are synthesized by ring-opening polymerization of cyclic ethers, ring-opening polymerization of cyclic acetals, high polymerization of aldehydes, polycondensation of glycols, and the like. Preferred representative compounds of the polyether compounds include polyethylene glycol and polyethylene glycol derivatives, and specific examples include polyethylene glycol; polyethylene glycol alkyl ether, polyethylene glycol polypropylene glycol ether, polyethylene glycol alkyl phenol ether, and polyethylene glycol. Ether compounds such as glycol nonyl phenyl ether and polyoxyethylene lanolin alcohol ether can be mentioned. Among these, polyethylene glycol having a molecular weight of 1,000 to 10,000 or less is particularly preferably used in the present invention. (3) Polyamide compound A preferable polyamide compound has −
It is a synthetic polymer compound with CO-NH-.
The compound is dicarboxylic acid and diamine or ω
-Synthesized by polycondensation of aminocarboxylic acids or ring-opening polymerization of lactams thereof. Further, the compound may be a saturated or unsaturated compound, or an aromatic compound. The compound can also be obtained commercially,
For example, Sanwa Kagaku Co., Ltd.'s Sanmide series products can be used. (4) Polyurethane compounds Polyurethane compounds have -NHCOO- in the main chain.
It is typically synthesized by a polyaddition reaction between a diisocyanate ester and a glycol. The polyurethane compound can also be obtained as a commercial product, for example, manufactured by Hodogaya Chemical Co., Ltd.
HSW-E ₁ can be used. The content of the heat-fusible substance that is immiscible with the above compound group is preferably 8 to 95% by weight, more preferably 8 to 95% by weight based on the total weight of the coloring material layer containing it
15-90% by weight. Note that heat-fusible substances immiscible with the above compound group include resin components described in JP-A-54-68253, such as polyvinyl chloride, polyvinyl acetate,
Although vinyl chloride-vinyl acetate copolymer, polystyrene, etc. may be included, it is rather undesirable to use too large a quantity. The thermofusible substances immiscible with the above compounds may be used alone or in combination of two or more. The colorant used in the heat-melting color material layer in the present invention may be appropriately selected from among pigments, including direct dyes, acid dyes, basic dyes, disperse dyes, and oil-soluble dyes (including metal-containing oil-soluble dyes). ) and various pigments. Specifically, the following can be mentioned. That is, as the yellow pigment, Kayalon Polyester Light Yellow 5G-
(Nippon Kayaku), Oil Yellow S-7 (white clay), Eisenspiron Yellow GRH Special (Hodogaya), Sumiplast Yellow FG (Sumitomo), Eisenspiron Yellow GRH (Hodogaya), etc. are preferably used. . Red pigments include Diaceriton Fastred R (Mitsubishi Kasei), Dianics Brilliant Red BS-E (Mitsubishi Kasei), Sumiplast Stretch FB (Sumitomo), Sumiplast Stretch FG (Sumitomo), and Kayalon. Polyester Pink RCL-E (Nippon Kayaku), Eisen Spiron Red GEH Special (Hodogaya), etc. are preferably used. Blue pigments include Diaceritone Fast Brilliant Blue R (Mitsubishi Kasei) and Dianics Blue EB.
-E (Mitsubishi Kasei), Kayalon Polyester Blue B
−SF Conch (Nippon Kayaku), Sumiplast Blue
3R (Sumitomo), Sumiplast Blue G (Sumitomo), etc. are preferably used. In addition, as yellow pigments, Hansa Yellow 3G, Tartrazine Lake, etc. are used.
As a red pigment, brilliant carmine FB-
Piure (Sanyo pigment), brilliant carmine 6B
(Sanyo Shiki), Alizarin Lake, etc. are used. As blue pigments, Cerulean Blue, Sumikaprint Cyanine Blue GN-O (Sumitomo), Phthalocyanine Blue, etc. are used. As black pigments, Carbon Black, Oil Black, etc. are used. used. The most preferred colorant used in the present invention is carbon black. The purpose of the present invention is to make the transfer density substantially the same if the applied energy is above a certain level. On the other hand, another color material layer may contain different types of colorants. In the present invention, a softener may be used, and examples of the softener include low softening point polymers selected from ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, and the like. Although the composition ratio of the coloring material layer of the present invention is not limited,
For example, when the heat-melting coloring material layer is composed of three layers and the layers are arranged adjacent to each other to obtain the layer structure of the present invention, it is preferable to do as follows. Coloring material layer: 30 to 95 parts of heat-fusible material to 100 parts (parts by weight, same hereinafter) of the total solid content of the coloring material layer.
parts (more preferably 40 to 90 parts), colorant is 5 to 90 parts
40 parts (more preferably 10 to 35 parts), 0 softeners
~20 parts (more preferably 1 to 15 parts). Coloring material layer: For 100 parts of the total solid content of the coloring material layer,
The thermofusible substance immiscible with the thermofusible substance is 8
-95 parts (more preferably 15-90 parts), 1-70 parts (more preferably 1-60 parts) of a heat-melting substance other than the immiscible heat-melting substance, and 5-40 parts of a colorant ( (more preferably 10 to 35 parts), and 0 to 15 parts (more preferably 1 to 10 parts) of softener. Coloring material layer: For 100 parts of the total solid content of the coloring material layer,
30 to 95 parts (more preferably 40 to 95 parts) of a thermofusible substance
90 parts), colorant 5 to 40 parts (more preferably 10 parts)
~35 parts) and 0 to 20 parts (more preferably 1 to 15 parts) of softener. As mentioned above, the purpose of the present invention is to make the transfer density substantially the same as long as the applied energy is above a certain level, and within the scope of this purpose, one color material layer is On the other hand, the content of the coloring agent in another coloring material layer may be different. The heat-melting coloring material layer of the present invention may contain various additives in addition to the above-mentioned components. For example, vegetable oils such as castor oil, linseed oil, olive oil, animal oils such as whale oil, and mineral oils may be suitably used. In the heat-sensitive transfer recording medium of the present invention, in order to apply the heat-melt coloring material layer onto the support, the heat-melt coloring material layer composition is hot-melt coated, or
Alternatively, it can be carried out by solvent coating with a coating solution obtained by dissolving or dispersing the composition in an appropriate solvent. As a coating method for the heat-melting coloring material layer of the present invention, any known technique such as a reverse roll coater method, an extrusion coater method, a gravure coater method, a wire bar coating method, etc. can be adopted, but in particular, a layer structure such as that of the present invention can be used. In this case, simultaneous multilayer coating can be applied to the front or part of the product. In addition, multiple coaters are prepared on one line,
It can also be painted. Note that a heat-sensitive transfer recording medium for multiple uses and for multiple colors can be produced using heat-melting coloring material layer compositions having several different color tones. That is, the longitudinal direction of the support is divided into predetermined intervals, for example, yellow, magenta,
When using a cyan or black hot-melt coloring layer composition, the yellow composition is coated on the support for a predetermined length in the longitudinal direction, and the yellow composition is formed into the multilayer structure of the present invention, and then A magenta composition is applied to a predetermined length and the magenta composition is formed into a multilayer structure according to the present invention, and then a cyan composition is applied to a predetermined length next to it and the cyan composition is formed into a multilayer structure according to the present invention. structure, then apply a black composition next to it by a predetermined length, and make the black composition into the multilayer structure of the present invention to form a multilayer structure layer divided into at least four sections, which is considered as one block, and this The blocks can be painted repeatedly. It is also preferable to provide markings for classification between the different colored layers. This makes it possible to print the same color multiple times and also to print in multiple colors. The thickness of each heat-melting coloring material layer of the present invention is 1 to 10 μm.
m is preferable, and more preferably 2 to 7 μm. In the present invention, when a subbing layer or adhesive layer is provided between the support and the heat-melt coloring material layer, the subbing layer or adhesive layer may be appropriately selected from, for example, hot melt adhesives. . Specific examples include ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, polyethylene, polyamide, polyester, petroleum resin, nylon, etc., and if one or more of these are used in combination, good. The thickness of the subbing layer or adhesive layer is preferably 0.5 to 2 μm. The support used in the thermal transfer recording medium of the present invention preferably has heat-resistant strength, high dimensional stability, and high surface smoothness. As for heat resistance strength,
It requires strength and dimensional stability to maintain the toughness of the support without being softened or plasticized by the heating temperature of a heat source such as a thermal head, and the surface smoothness requires a heat-fusible substance on the support. It is desired that the color material layer has sufficient smoothness to exhibit a good transfer rate. The smoothness should be 100 seconds or more in a smoothness test using a Beck testing machine (JIS P 8119).
When the time is 300 seconds or more, images with better transfer rate and reproducibility can be obtained. Examples of materials include:
Paper such as plain paper, condenser paper, laminated paper, coated paper, resin films such as polyethylene, polyethylene terephthalate, polyester, polystyrene, polypropylene, polyimide, paper-resin film composites, metal sheets such as aluminum foil, etc. Both are preferably used. The thickness of the support is usually approximately
It is preferably 60 μm or less, particularly 2 to 20 μm.
Furthermore, the heat-sensitive transfer recording medium of the present invention may have a layer other than the heat-melting coloring material layer such as a protective layer,
Further, the structure on the back side of the support is arbitrary, and a backing layer such as a sticking prevention layer may be provided. [Effects of the Invention] According to the present invention, a transferred image with a constant transfer density can be obtained if the applied energy is above a certain level, and a constant print quality can be obtained many times without being affected by subtle changes in the applied energy. This is fundamentally different from conventional thermal transfer recording media that can be used multiple times, and the effect is that adjacent coloring material layers are peeled off near the boundary, allowing for layer-by-layer transfer. In particular, in the present invention, the coloring material layers are arranged adjacent to each other, and it is literally possible to print multiple times with just the coloring material layer, so the film thickness is smaller than when an intermediate layer is interposed between the coloring material layers. This has the effect that the transfer image can be made thinner, and therefore a transferred image with good resolution can be obtained. [Example] Examples will be given below, but the present invention is not limited thereto. Note that "parts" used below indicate "parts by weight." Example 1 The following multilayer composition was sequentially coated on a 4.0 μm thick polyethylene terephthalate film support by a solvent method or a hot melt method using a wire bar so that the total dry film thickness was 11 μm. A thermal transfer recording medium sample was obtained. Composition and thickness of each layer (listed in order from the support): Adhesive layer (1) Composition Ethylene-ethyl acrylate copolymer (NUC 6070 manufactured by Nippon Unicar Co., Ltd.) 100 parts (2) Thickness: 1 μm (dry Film thickness, same below): Coloring material layer (1) Composition Carnauba wax 25 parts paraffin wax (mp = 62℃) 45 parts carbon black 15 parts ethylene-vinyl acetate copolymer 7 parts montan wax (mp = 63 ℃) 8 parts (2) Thickness; 5 μm: Coloring material layer (1) Composition Polyester wax (Plaxel 260 manufactured by Daicel Chemical Co., Ltd.) 73 parts Carbon black 15 parts Carnauba wax 5 parts Ethylene-vinyl acetate copolymer 7 parts (2) Thickness: 5 μm This thermal transfer recording medium sample was shaped into a ribbon with a width of 8 mm, and a thermal printer (heating element density
A prototype machine equipped with an 8dot/mm thin film line thermal head. ) using applied energy of 0.71mJ/
dot was given and recorded (printed) on plain paper. In addition,
Commercially available high-quality paper (100 sec) was used as plain paper. The results are shown in Table 1. Example 2 A thermal transfer recording medium sample was obtained in the same manner as in Example 1, except that the coloring material layer and the coloring material layer had the following compositions. (1) Coloring layer carnauba wax 10 parts Polyethylene wax 15 parts Paraffin wax 20 parts Micro wax 20 parts Carbon black 15 parts Ethylene-ethyl acrylate copolymer 20 parts (2) Coloring layer paraffin wax 20 parts Polyethylene glycol 30 parts Carbon black 15 parts Oxidized wax 10 parts Hoechst F 25 parts Example 1 using the above thermal transfer recording medium sample
I printed it in the same way. The results are shown in Table 1. Comparative Example 1 A comparative thermal transfer recording medium sample was obtained in the same manner as in Example 1, except that the coloring material layer was not provided and the thickness of the coloring material layer was 10 μm. Example 1 Using this thermal transfer recording medium sample
I printed it using a thermal printer in the same way. The results are shown in Table 1.

[Table] As is clear from the table above, in the samples of the present invention, the concentrations were sufficient in both the first and second tests. Therefore, it can be seen that according to the present invention, it is possible to print multiple times with substantially the same transfer density. On the other hand, in the case of the comparative sample, a high-density image was obtained the first time, but no images were obtained after the second time.

Claims (1)

[Scope of Claims] 1. A heat-sensitive transfer recording medium having a heat-melting coloring material layer on a support, wherein the coloring material layer is composed of two or more multilayers, and one layer of the coloring material layer is made from the following compound group. A coloring material layer adjacent to the coloring material layer contains at least one selected heat-melting substance and is immiscible with the heat-melting material, and at least one selected from the following compound group. 1. A heat-sensitive transfer recording medium characterized by containing a heat-melting substance of various types. [Compound group] Animal-based wax Plant-based wax Mineral-based wax Petroleum-based wax Synthetic hydrocarbon-based wax Modified wax