JPH0443080A - Thermal recording material - Google Patents

Abstract

PURPOSE:To improve the mechanical strength of the laminate on a recording support by forming all of the self-supporting colorant layer on the recording support and the colorant layer and/or releasable support thereon from a polymer having a crosslinked structure. CONSTITUTION:A thermal recording material consists of a recording support and a self-supporting colorant layer and heat is imagewise applied to the self-supporting colorant layer and this self-supporting colorant layer is peeled off from the aforementioned recording support to obtain the recording support having an image. In this thermal recording material, the aforementioned self-supporting colorant layer is formed from a polymer having crosslinked structure. The polymer having the crosslinked structure can be obtained by subjecting a non- crosslinked polymer to crosslinking reaction. The recording support desirably has good heat-resistant strength and high dimensional stability and, as the material thereof, there are papers such as plain paper, condenser paper, laminated paper or coated paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material that has excellent mechanical strength and improved solvent resistance and heat resistance.

[Prior art and problems to be solved by the invention] Conventional beer-apart type heat-sensitive recording materials basically have a structure in which a heat-softening coloring material layer is laminated on a recording support, and imagewise By peeling off the heat-softening color material layer after heating, an image can be formed on the recording support.

However, this type of heat-sensitive recording material has an insufficient mechanical strength due to its heat-softening coloring material layer, and may be damaged during peeling.

Further, this type of heat-sensitive recording material cannot be said to be satisfactory in terms of solvent resistance, heat resistance, etc.

The present invention has been made in view of the above circumstances.

In other words, one object of the present invention is to provide a heat-sensitive recording material formed by laminating a self-supporting coloring material layer on a recording support, as well as a coloring material layer (which may correspond to a heat-softening coloring material layer) on the recording support. .)
In a heat-sensitive recording material formed by laminating a peelable support and a peelable support,
The object of the present invention is to provide a heat-sensitive recording material that has improved mechanical strength of a self-supporting coloring material layer, a coloring material layer, and a peelable support, and also has excellent performance in terms of solvent resistance, heat resistance, etc.

[Means for Solving the Problem] The invention of claim 1 for achieving the above object comprises a recording support and a self-supporting coloring material layer, and imagewise heat is applied to the self-supporting coloring material layer. In the heat-sensitive recording material, the recording support having an image can be obtained by peeling the self-supporting coloring material layer from the recording support after application of the self-supporting coloring material layer. This is a heat-sensitive recording material characterized by being made of a polymer having the following properties.

Further, the invention of claim 2 comprises a recording support, a coloring material layer, and a peelable support, and the coloring material layer is peeled off from the recording support after imagewise heat is applied to the coloring material layer. Accordingly, the present invention is a heat-sensitive recording material capable of obtaining the recording support having an image, characterized in that the peelable support and/or the coloring material layer are made of a polymer having a crosslinked structure.

The present invention will be explained in detail below.

One Layer Structure The heat-sensitive recording medium of the invention according to claim 1 is basically formed by laminating a recording support and a self-supporting coloring material layer.

The heat-sensitive recording material according to the second aspect of the invention is basically formed by laminating a recording support, a coloring material layer, and a peelable support in this order.

An intermediate layer such as an adhesive layer (adhesive layer is also included in this concept) may be provided between each layer, and a back coat layer or the like may be provided on the back surface of the recording support.

Furthermore, an anti-sticking layer may be provided on the surface of the peelable support.

-Recording support- In both the invention of claim 1 and the invention of claim 2, it is desirable that the recording support has good heat resistance strength and high dimensional stability.

The materials include, for example, papers such as plain paper, condenser paper, laminated paper, and coated paper; resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, and polyimide; composite Ni-aluminum foil of paper and resin film, etc. metal sheet, composite of metal sheet and resin film; paper, resin film,
For example, a metal sheet or the like provided with a layer of a heat-softening resin or a heat-fusible substance, which will be described later, can be mentioned.

The thickness of these recording supports is preferably thin in order to maintain good responsiveness and sensitivity of the heat-sensitive recording medium, but if they become too thin, self-supporting properties are lost.

That is, the thickness of the recording support is usually 1 to S,00
0 uLm, and more preferably a range of 3 to 11 00#Lm.

The shape of the recording support is appropriately determined depending on the use of the heat-sensitive recording material, and may be tape-shaped, sheet-shaped,
Any shape such as a label shape can be adopted.

(1) Self-Supporting Coloring Material The self-supporting coloring material layer in the invention of claim 1 is basically made of a polymer having a crosslinked structure and contains a diffusive coloring material as a coloring material.

Polymers having such a crosslinked structure can be obtained by subjecting uncrosslinked polymers listed below to a crosslinking reaction.

Preferred examples of the uncrosslinked polymer include polyvinyl alcohol, casein, starch, polyvinyl butyral, polyethylene, polyester, acrylic resin, polyester acrylate, polyol acrylate, polyether acrylate, polyurethane acrylate, oligoacrylate, and epoxy acrylate.

In order to crosslink the uncrosslinked polymer, a crosslinking agent, a photoinitiator, etc. listed below are appropriately selected, and a crosslinking reaction is carried out by appropriately irradiating with heat, radiation, electron beams, ultraviolet rays, etc.

Examples of crosslinking agents include urea, melamine/formalin resins, dialdehydes, phenolic resins, epoxy resins, melamine resins, isocyanates, dialdehydes, organic peroxides, and carbon black.

Examples of photoinitiators include benzoin, acetophenone, benzyl ketal, and ketone/amine initiators.

Next, the diffusive coloring materials include C,I Cisverse Yellow 3, C,I Cisperse Orange 3, C,I Cisperse Blue 14. Typical examples include C,I dispersion red 4 and C,I dispersion violet 1.

The above-mentioned coloring materials are not limited to the use of one type, but two or more types can be used in combination.

The content of the coloring material in the self-supporting coloring material layer is usually
It is within the range of 5 to 40% by weight, preferably 10 to 30% by weight.
Within the range of % by weight.

In addition to the above-mentioned components, the self-supporting coloring material layer contains one or more additives such as waxes, surfactants, higher fatty acid derivatives, higher aliphatic alcohols, higher aliphatic ethers, and phosphoric acid esters. It may also be included.

The thickness of the self-supporting coloring material layer is preferably thin enough to be peelable from the recording support and to allow movement of the coloring material by application of thermal energy in terms of high sensitivity and responsiveness.
Usually within the range of 0.5 to 104 m, preferably 1
~5Bm.

The self-supporting coloring material layer can be formed in accordance with the method described below in the section of the coloring material layer.

One Coloring Material Layer In the invention of claim 2, if the peelable support described later is not formed of a polymer having a crosslinked structure, it is necessary to form this coloring material layer of a polymer having a crosslinked structure.

In this case, a thermally diffusive coloring material is used as the coloring material.

The type and amount of the polymer, as well as the type and manufacturing method of the polymer having a crosslinked structure, are the same as those described in the section of the self-supporting coloring material layer.

On the other hand, when the peelable support described below is formed from a polymer having a crosslinked structure, the coloring material layer is basically formed from a binder and a coloring material as described below, or the self-supporting color is It is formed from a polymer having a crosslinked structure as described in the material layer section and a diffusive coloring material.

In the former case, the colorant layer can be broadly classified into cohesive failure type, interfacial peeling type, and colorant diffusion type depending on the behavior during heating. Determined by selecting .

The binder used in the present invention includes thermofusible substances and/or
Alternatively, thermoplastic resins can be mentioned.

Specific examples of heat-melting substances include vegetable waxes such as carnauba wax, wood wax, auriculie wax, and Nispar wax; animal waxes such as beeswax, insect wax, shellac wax, and spermaceti wax; paraffin wax, microcrystal wax, polyethylene wax; Petroleum waxes such as ester waxes and acid waxes; waxes such as mineral waxes such as montan wax, oshikerite and ceresin; and higher fatty acids such as behenic acid: higher alcohols such as valmityl alcohol, stearyl alcohol, behenyl alcohol, marganyl alcohol, myricyl alcohol and eicosanol; higher fatty acids such as cetyl palmitate, myricyl palmitate, cetyl stearate and myricyl stearate Esters: Amides such as acetamide, propionic acid amide, balmitic acid amide, stearic acid amide and Amitowex; and higher amines such as stearylamine, behenylamine and valmitylamine.

The thermoplastic resins include ethylene copolymers, polyamide resins, polyester resins, polyurethane resins, polyolefin resins, acrylic resins, vinyl chloride resins, cellulose resins, rosin resins, ionomer resins, and petroleum resins. resins such as natural rubber, styrene-butadiene rubber, imprene rubber, chloroprene rubber, and diene copolymers; rosin derivatives such as ester gum, rosin maleic acid resin, rosin phenol resin, and hydrogenated rosin; and the softening point of phenolic resins, terpene resins, cyclopentadiene resins, aromatic hydrocarbon resins, etc. 50 to 150°C
Examples include high molecular weight compounds.

In order to form a heat-softening coloring material layer having a desired heat-softening point or heat-melting point, it is necessary to appropriately select the heat-melt material and thermoplastic material.

This is because the thermal softening point or thermal melting point cannot be adjusted.
The same can be said about adjusting mechanical strength.

Next, as the coloring material to be used in combination with the binder, the following representative examples include pigments (inorganic and organic) and dyes.

Inorganic pigments include titanium dioxide, carbon black,
Examples include zinc oxide, Prussian blue, cadmium sulfide, iron oxide and chromates of lead, zinc, barium and calcium.

Examples of organic pigments include azo, thioindigo, anthraquinone, anthanthrone, and triphenedioxazine pigments, hat dye pigments, phthalocyanine pigments, such as copper phthalocyanine and derivatives thereof, and quinacridone pigments.

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

In addition, the diffusive coloring materials mentioned in the section of the self-supporting coloring material layer may also be used.

The above-mentioned coloring materials are not limited to the use of one type, but two or more types can be used in combination.

The content of the coloring material in the coloring material layer is usually 5 to 40 il.
% by weight, preferably from 10 to 30% by weight.

In addition to the above-mentioned components, the coloring layer may contain one or more additives such as waxes, surfactants, higher fatty acid derivatives, higher aliphatic alcohols, higher aliphatic ethers, and phosphoric acid esters. You can leave it there.

The thickness of the coloring material layer is preferably thin so that it can be peeled off from the recording support, and from the viewpoint of high sensitivity and responsiveness, so that the coloring material can be moved by application of thermal energy, and is usually 0.
．． Within the range of 5 to 10 pm, preferably 1 to 57z
It is within the range of m.

The coloring material layer can be formed by a known coating technique, such as a reverse roll coater method, an extrusion coater method, a gravure coater method, a wire bar coating method, an air knife coater method, a plate coater method, and the like.

During this coating, is it necessary to knead the binder, coloring material, and solvent, or additionally filler, etc.?As the solvent, one of the following may be used.

For example, wood, acetone, methyl ethyl ketone (MEK)
Ketones such as , methyl isobutyl ketone (MIBK), cyclohexanone, alcohols such as methanol, ethanol, propatool, esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl acetate propyl lactate, ethylene glycol monoacetate, diethylene glycol dimethyl ether, Ethers such as 2-ethoxyethanol, tetrahydrofuran, dioxane, benzene,
Aromatic hydrocarbons such as toluene and xylene: methylene chloride, ethylene chloride, carbon tetrachloride, chloroform,
Halogenated hydrocarbons such as ethylene chlorohydrin and dichlorobenzene may be used, and each of these can be used alone or in combination of two or more.

In addition, examples of the crosstalk means include a two-roll mill, a three-roll mill, a ball mill, a pebble mill, a sight grinder, a Sq6gvari attritor, a high-speed impeller disperser, a high-speed stone mill, a high-speed impact mill, a disper kneader-1 high-speed mixer, and a homogenizer. , ultrasonic disperser, etc.

- Peelable support - Peelable support in the invention of claim 2 (Peeling here means peeling off from the recording support while laminated on the coloring material layer, and peeling off from the coloring material layer) That's not true.)
When the colorant layer is not formed of a polymer having a crosslinked structure, it is important to form it of a polymer that has a crosslinked structure.

The type and manufacturing method of the polymer having such a crosslinked structure are the same as those described in the section of the self-supporting coloring material layer.

However, in this case, it is not necessary to add a diffusive coloring material.

Further, when the coloring material layer is formed of a polymer having a crosslinked structure, the releasable support may be formed of a polymer having a crosslinked structure as described in the section of the self-supporting coloring material layer. Alternatively, it may be formed of a polymer such as the non-crosslinked thermoplastic resin mentioned in the section of the coloring material layer.

The thickness of the releasable support is usually 1 to 30 pm,
Preferably it is 2 to 20 pm.

If the thickness is less than 1 gm, the effect of the present invention may not be fully exhibited, and if it exceeds 30 gm, when trying to obtain an image by imagewise heating, there will be a transmission loss of the applied thermal energy and diffusion. This is undesirable because it may cause the print quality to deteriorate.

The principle of printing using the heat-sensitive recording material of the present invention, that is, the image forming mechanism, is as described below.

That is, in the cohesive failure type or interfacial peeling type, heat is first applied from the recording support side, or heat is applied imagewise to the thermosensitive recording material from the peelable support side.

Then, the heated portion of the coloring material layer enters a molten state and develops an adhesive force stronger than the adhesive force with which it had previously adhered to the recording support.

Next, the coloring material layer and/or the peelable support are peeled off from the recording support.

At this time, since the heat-sensitive recording material of the present invention is made of a peelable support or a polymer having a crosslinked structure with high mechanical strength, it is possible to smoothly peel the coloring material layer from the recording support without causing damage. Ru.

When peeled off in this way, or during peeling, the coloring material layer in the heated portion is separated from the entire coloring material layer (cohesive failure, interfacial failure) and remains as it is on the recording support.

As a result, an image is formed on the surface of the recording support by the heat-softening coloring material layer remaining in the image quiz.

On the other hand, in the case of a colorant diffusion type, that is, a self-supporting colorant layer or a colorant layer in which the heat transfer rate of the colorant is high, a first-order phenomenon occurs.

When the heat-sensitive recording material is imagewise heated in the same manner as described above, either the self-supporting coloring material layer or the diffusive coloring material in the coloring material layer moves toward the recording support.

Next, the self-supporting coloring material layer is peeled off from the recording support, or the coloring material layer is peeled off from the recording support with a peelable support laminated thereon.

In either case, the coloring material remains imagewise on the recording support to form one image.

In the heat-sensitive recording material of the present invention having the image forming mechanism as described above, as described above, the self-supporting coloring material layer or the peelable support and/or the coloring material layer are formed from a polymer having a crosslinked structure. As a result, mechanical strength, solvent resistance, and heat resistance can be improved.

[Example] Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

In the following, "1 part" represents "part by weight."

(Example 1) Raw material A having the following composition was applied onto a polyethylene terephthalate film having a thickness of 7 Spm using a wire bar to form a layer having a thickness of 54 m, and the obtained laminate was used as a memory support.

L-■-5 Polyester resin: 90 parts Silicone-modified acrylic resin: 10 parts Next, raw material B having the following composition was applied onto the recording support using a wire bar. A self-supporting coloring material layer having an S thickness of 7 pm was formed.

Polyvinyl alcohol: 70 parts Blue dye (Butterpur M: manufactured by Hoechst): 20 parts Gluogizar: 10 parts A silicone resin emulsion was applied onto the self-supporting color material layer to form a resin layer with a thickness of 0.2 gm.

The heat-sensitive recording material thus obtained was heated with an applied energy of 1 mJ.
/dot, Herato pressure 3Kg weight, heating element density 8dot
Printing was performed using a t/mm line thermal head.

After that, when the recording support and the self-supporting coloring material layer were peeled off at the interface, the self-supporting coloring material layer could be peeled off without thermal damage, breakage, or deformation, and the recording support An image-wise image was formed on the body.

Further, when the surface of the recording medium before printing was wiped with a cloth impregnated with water, no change was observed in the self-supporting coloring material layer.

(Comparative Example 1) A thermosensitive recording material was produced in the same manner as in Example 1 except that glyoxal was removed from raw material B.

When printing and peeling were performed in the same manner, slight deformation of the self-supporting color material layer was observed.

Furthermore, when wiped with a cloth impregnated with water, the self-supporting coloring material layer was significantly attacked by the water.

(Example 2) The following raw material C was applied onto a crosslinked polyethylene film having a thickness of 10 parts to provide an adhesive layer.

Paraffin wax: 97 parts (emulsion) Ethylene-vinyl acetate copolymer: 3 parts (emulsion) Next, the following raw materials were applied onto the adhesive layer to determine its thickness. A resin layer of IBm was provided, and a water-based weak adhesive was further applied thereon to provide an adhesive layer having a thickness of lp-m.

Otori L-dan acrylic resin 75 parts (FC
30. Manufactured by Nippon Kayaku Co., Ltd.) Carbon black 20 parts Ethylene-vinyl acetate copolymer 5 parts or more A heat-sensitive recording material was created by pasting it on the paper.

Regarding this heat-sensitive recording material, printing was carried out in the same manner as in Example 1.
When peeling was performed, the polyethylene film of the peeling support was not damaged by heat and could be peeled off.

The tensile strength of this polyethylene film was measured and was found to be 130 kg/cm2.

(Comparative Example 2) A thermosensitive recording material was produced in the same manner as in Example 2 except that the crosslinked polyethylene film was changed to a low density polyethylene film.

When an attempt was made to print and release i4 on this heat-sensitive recording material in the same manner, the polyethylene film of the release support was significantly deformed and was broken.

The tensile strength of this polyethylene film is 70Kg
/cm2.

[Effects of the Invention] In the heat-sensitive recording material of the present invention, the self-supporting coloring material layer on the recording support, and the coloring material layer and/or the peelable support on the recording support are all made of a polymer having a crosslinked structure. As a result, the mechanical strength of the laminate on the recording support is improved and it can be smoothly peeled off from the imaged recording support without damaging it.

Further, the presence of the peelable support is effective in improving the solvent resistance and heat resistance of the heat-sensitive recording material of the present invention.

Claims (2)

[Claims] (1) Consisting of a recording support and a self-supporting coloring material layer, applying imagewise heat to this self-supporting coloring material layer and then peeling off this self-supporting coloring material layer from the recording support. A heat-sensitive recording material capable of obtaining the recording support having an image according to the method, wherein the self-supporting coloring material layer is made of a polymer having a crosslinked structure. (2) Consisting of a recording support, a coloring material layer, and a releasable support,
In a heat-sensitive recording material in which the recording support having an image can be obtained by applying imagewise heat to the coloring material layer and then peeling the coloring material layer from the recording support, the releasable support 1. A heat-sensitive recording material, wherein the body and/or the coloring material layer are made of a polymer having a crosslinked structure.