JPH0259798B2 - - 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 inventor has discovered that in a thermal transfer recording medium having two or more heat-melting color material layers on a support, at least one of the color material layers is indirectly adjacent to the other coloring material layer via an intermediate layer, and at least one of the indirectly adjacent coloring material layers and the intermediate layer contain at least one type of heat selected from the following compound group. The above technical problem is solved by the intermediate layer containing a fusible substance and adjacent to a coloring material layer containing the fusible substance containing a fusible substance that is immiscible with the fusible substance. The present invention was based on this discovery. [Compound Group] Animal-based waxes Plant-based waxes Mineral-based waxes Petroleum-based waxes Synthetic hydrocarbon-based waxes Modified waxes A multilayer thermal transfer recording medium has two coloring material layers indirectly adjacent to each other via an intermediate layer, At least one of the coloring material layers and the intermediate layer contain a heat-fusible substance selected from the above compounds, and the intervening intermediate layer contains a heat-fusible substance that is immiscible with the selected heat-fusible substance. If it is contained, it belongs to the technical scope of the present invention. Even in the case of having three or more coloring material layers, the conditions of the present invention described above may be satisfied between at least one coloring material layer and the intermediate layer adjacent thereto, but each of all coloring material layers It is desirable that the conditions of the present invention be satisfied between this and the adjacent intermediate layer. The present invention will be explained in more detail below. The heat-sensitive transfer recording medium of the present invention has two or more heat-melting coloring material layers provided on a support, and the heat-melting coloring material layers are preferably attached to the support via an adhesive layer. It is formed in multiple layers of two or more layers, and an intermediate layer is provided between the two or more 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, is transferred to the transfer paper side, and can obtain printing with the necessary transfer density in one transfer. means. Further, the intermediate layer is a layer that is interposed between the heat-melting color material layers and can distinguish the color material layers, and cannot provide printing with the necessary transfer density in one transfer by itself. It refers to a layer. In the present invention, a preferred layer structure includes, for example, an adhesive layer, a coloring material layer, an intermediate layer,
A coloring material layer is coated, the coloring material layer and/or the coloring material layer and the intermediate layer contain at least one kind of so-called low polar heat-melting substance selected from the group of compounds, and the intermediate layer contains A multilayer structure containing a heat-fusible substance that is immiscible with the heat-fusible substance (so-called highly polar) can be mentioned. With such a configuration, part or all of the composition of the coloring material layer has immiscibility with the coloring material layer and/or the wax of the coloring material layer. The present invention utilizes the reduction in breaking strength (removability between the coloring material layer and/or the coloring material layer and the intermediate layer) based on this immiscibility. In other words, in the process of applying energy to melt the coloring material layer and transferring (peeling it off) to the transfer paper side, (1) near the interface between the coloring material layer and the intermediate layer, and (2) near the interface between the coloring material layer and the intermediate layer. , or (3) inside the intermediate layer. As a result, 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, an intermediate layer, a coloring material layer, an intermediate layer, and a coloring material layer can be laminated on the coloring material layer, respectively. FIG. 1 of the accompanying drawings shows an example in which layers up to the coloring material layer are laminated. In the above case, the coloring material layers may each have the same composition, but it is rather preferable to vary the melting point, viscosity, coloring material concentration, and film strength. Another embodiment of the present invention has the following layer configuration. That is, as shown in FIG. 2 or 3, it has the above coloring material layer, intermediate layer, and coloring material layer, and (1) has a coloring material layer directly on the coloring material layer. (See Figure 2)
or (2) there is a coloring material layer directly below the coloring material layer (see Figure 3), and in the case of (1) above, the relationship between the coloring material layers is ), the relationship between the coloring material layers is such that one coloring material layer contains at least one heat-melting substance selected from the above compound group, and the other coloring material layer contains the heat-melting substance selected from the above compound group. In other words, it is configured to contain a heat-melting substance that is immiscible with a chemical substance. The same holds true when a directly adjacent coloring material layer is further provided. A detailed explanation on this point is given in Japanese Patent Application No. 1983-232424 filed by the present applicant. Note that the above intermediate layer and other intermediate layers may contain a coloring agent. In the present invention, it is preferable that the layer containing at least one type of heat-fusible substance selected from the above-mentioned group of compounds does not substantially contain a heat-fusible substance that is immiscible therewith, and even if it is contained, its content is 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 honey wax, 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 addition, in the present invention, hydrogenated wax such as castor wax, opal wax, etc. 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 refers to a state in which the two are mixed by thermal melting or softening and then exhibits a cloudy state, an oil drop shape, a layer separation, or an incompatible state, which may be detected by 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 material having a melting point (MP) or softening point of 35 to 100 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 ether 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 -O- 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. Examples include ether compounds such as glycol nonyl phenyl ether and polyoxyethylene lanolin alcohol ether. 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 preferred 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 −HNCOO− in the main chain.
It is typically synthesized by polyaddition reaction of diisocyanate and glycol. The polyurethane compound can also be obtained as a commercial product, and for example, urethane wax HSW-E ₁ manufactured by Hodogaya Chemical Co., Ltd. can be used. The content of the thermofusible substance immiscible with the above compound group is preferably 8 to 100% by weight, more preferably 8 to 100% by weight based on the total amount of the intermediate layer containing the substance.
It is 20-100%. 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. In the present invention, a coloring agent is contained in the heat-melting coloring material layer, but it can also be contained in the intermediate layer. When contained in the intermediate layer, it can contribute to improving the transfer density of the coloring material layer in contact with the intermediate layer. The coloring agent used in the present invention may be appropriately selected from among pigments, including direct dyes, acid dyes,
It can be selected from dyes such as basic dyes, disperse dyes, oil-soluble dyes (including metal-containing oil-soluble dyes), and various pigments. Specifically, the following can be mentioned. That is, as yellow pigments, Kayalon Polyester Light Yellow 5G-S (Nippon Kayaku), Oil Yellow S-7 (white clay), Eisen Spiron Yellow GRH Special (Hodogaya), Sumiplast Yellow FG (Sumitomo), Eisen Spiron yellow
GRH Special (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 Stret HFG (Sumitomo),
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), Phthacyanine Blue, etc. are used. As black pigments, Carbon Black, Oil Black, etc. are used. is 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 coloring material layer may contain different types of coloring agents. 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, it is preferably 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). Intermediate layer: For 100 parts of the total solid content of the intermediate layer,
The thermofusible substance immiscible with the thermofusible substance is 8
-90 parts (more preferably 20-90 parts), 10-70 parts (more preferably 10-60 parts) of a heat-melting substance other than the immiscible heat-melting substance, and 0-40 parts (more preferably 10-60 parts) of a colorant. Preferably 0 to 35 parts), softener 0 to 20 parts (more preferably 5 to 15 parts). 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. Further, as in the example of the intermediate layer, when a heat-fusible substance other than an immiscible heat-fusible substance is contained, the content is preferably 70% or less of the total heat-fusible substance, and more preferably Preferably it is 60% or less, particularly preferably 50% or less. 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 coat the heat-melting coloring material layer and the intermediate layer on the support,
For example, it can be formed by hot-melt coating the heat-melt coloring layer composition or intermediate layer composition, or by solvent coating a coating solution obtained by dissolving or dispersing the composition in an appropriate solvent. As a coating method, any known technique such as a reverse roll coater method, an extrusion coater method, a gravure coater method or a wire bar coating method can be adopted, but especially in the case of a layer structure like the one of the present invention, Simultaneous multilayer coating is preferred. It is also preferable to prepare a plurality of coaters in one line for coating. 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 block is You can apply it 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.
Moreover, the intermediate layer preferably has a thickness of 0.05 to 40 μm, more preferably 0.5 to 2 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. All are suitably used. The thickness of the support is usually approximately
It is preferably 60 μm or less, particularly 2 to 20 μm.
Furthermore, the thermal transfer recording medium of the present invention may have a protective layer or the like, and the structure on the back side of the support may be 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 coloring material layers that are indirectly adjacent to each other through the intermediate layer are pulled one by one in the vicinity of the boundary. It exhibits the effect that it can be peeled off and transfer layer by layer is possible. In particular, in the present invention, since a unique intermediate layer is provided, it is possible to reliably peel off each coloring material layer, and furthermore, it has the effect that a transferred image having a constant transfer density can be reliably 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 onto 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 15 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 35 parts Paraffin wax (mp=62℃) 45 parts Carbon black 15 parts Ethylene-vinyl acetate copolymer 5 parts Density wax 5 parts (2) Thickness: 4 μm: Intermediate layer (1) Composition: Ethylene-vinyl acetate copolymer 10 parts Paraffin wax (MP=62℃) 45 parts Polyethylene glycol (Mw=6000) 45 parts (2) Thickness: 2 μm: Coloring material Layer (1) Composition Carnauba wax 42 parts Paraffin wax (MP=62℃) 30 parts Carbon black 15 parts Ethylene-vinyl acetate copolymer 5 parts Density wax 8 parts (2) Thickness: 4 μm This thermal transfer recording medium Cut the sample into a ribbon with a width of 8 mm and print it on a thermal printer (heating element density
A prototype machine equipped with an 8dot/mm thin film line thermal head. ) using an 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. Comparative Example 1 A comparative thermal transfer recording medium sample was obtained in the same manner as in Example 1 except that the composition of the coloring material layer was changed as shown below. (Composition of intermediate layer) Ethylene-vinyl acetate copolymer 10 parts Paraffin wax (mp=62°C) 90 parts 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. Note that Example 1
After the first printing, a small amount of the remaining layer surface was sampled and analyzed, and polyethylene glycol was detected. On the other hand, in the case of the comparative sample, a high-density image is obtained the first time, but the second
No images were obtained after the first visit.

[Brief explanation of the drawing]

FIGS. 1 to 3 are layer configuration diagrams showing examples of the present invention in which transfer printing is performed three times each.

Claims (1)

[Claims] 1. In a heat-sensitive transfer recording medium having two or more heat-melting coloring material layers on a support, at least one of the coloring material layers is indirectly connected to another coloring material layer via an intermediate layer. , at least one of the indirectly adjacent coloring material layers and the intermediate layer contain at least one heat-melting substance selected from the following compound group,
A heat-sensitive transfer recording medium, wherein the intermediate layer adjacent to the coloring material layer containing the heat-melting substance contains a heat-melting substance that is immiscible with the heat-melting substance. [Compound group] Animal-based wax Plant-based wax Mineral-based wax Petroleum-based wax Synthetic hydrocarbon-based wax Modified wax