JPS63144086A - Thermal recording medium - Google Patents

Abstract

PURPOSE:To obtain a colored image having high resistance to heat, light and chemicals, by providing an undercoat layer between a base and a colored layer and an adhesive layer between the colored layer and a thin metallic film layer, as optional components, and incorporating a pigment having a predetermined average particle diameter in at least one of the colored layer, the undercoat layer and the adhesive layer. CONSTITUTION:A base 1 and a colored layer 2, a thin metallic film layer 3 and a protective layer 4 sequentially provided in that order on one side of the base 1 are provided as essential components, whereas an undercoat layer 5 between the base 1 and the colored layer 2 and an adhesive layer 6 between the colored layer 2 and the thin metallic film layer are provided as optical components, and a pigment having an average particle diameter of 1-10mum is incorporated in at least one of the colored layer 2, the undercoat layer 5 and the adhesive layer 6, thereby constituting a thermal recording medium in a laminate form. The pigment provides the coated layer with appropriate ruggedness, whereby contrast of recorded images is increased, and clear images can be recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is used for output records of electronic computers, facsimile machines, tickets, cards, etc. The present invention relates to a heat-sensitive recording medium that records data using physical changes.

(Prior art) (Problems to be solved) The thermal recording method, which uses physical or chemical changes in substances caused by thermal energy to obtain images, does not generate noise during recording and does not require development and fixing. Due to its advantages such as the fact that it does not produce any color, it is expected to be used not only for copying documents, etc., but also as a coloring method for computer output records and facsimile reception records. Many types of recording materials have been proposed to date for use in this thermal recording method, but among them, recording materials that use leuco bodies such as fluoran dyes as color formers are known for their color development speed, or thermal sensitivity. It is attracting attention because of its excellent performance. However, thermal recording paper using leuco bodies as a coloring agent has the disadvantage that it easily develops color under pressure, and furthermore, it also develops color in the presence of organic solvents such as alcohol, resulting in poor chemical resistance and light resistance. It has various drawbacks such as poor water resistance and poor heat resistance.

An object of the present invention is to provide a heat-sensitive recording material used in the above-mentioned heat-sensitive recording method, which can produce colored images with strong heat resistance, light resistance, and chemical resistance.

(Means for Solving the Problems) (Operations) The present invention was developed as a result of intensive studies to solve the various problems mentioned above, and its outline is as follows.

The essential components include a support, a colored layer sequentially provided outward on one side of the support, a metal thin film layer, and a protective layer,
The under layer between the support and the colored layer and the adhesive layer between the colored layer and the metal thin film layer are optional constituent elements, and the average particle size is 1 to 1.
1. A heat-sensitive recording medium comprising a laminate in which at least one of the colored layer, under layer, and adhesive layer contains a 0μ pigment.

More specifically, the purpose is to provide the following:

(1) A heat-sensitive recording medium characterized in that a colored layer containing a pigment having an average particle size of 1 to 10 μm, a metal thin film layer, and a protective layer are sequentially laminated on a support.

(2) A heat-sensitive recording medium in which a colored layer, an adhesive layer mainly composed of a thermoplastic polymer, a metal thin film layer, and a protective layer are sequentially laminated on a support, wherein at least one of the colored spring adhesive layers A heat-sensitive recording medium characterized in that the layer contains a pigment having an average particle size of 1 to 10 μm.

(3) A heat-sensitive recording medium comprising an under layer, a colored layer, a metal thin film layer, and a protective layer sequentially laminated on a support, wherein at least one of the under layer and the colored layer has an average particle size. 1
A heat-sensitive recording medium characterized by containing a pigment of ~10 μm.

(4) A thermosensitive recording medium comprising an under layer, a colored layer, an adhesive layer containing a thermoplastic polymer as a main component, a metal thin film layer, and a protective layer sequentially laminated on a support, the under layer, the colored layer, At least one layer of the adhesive layer has an average particle size of 1 to 1.
A heat-sensitive recording medium characterized by containing a pigment of No. 07a.

In the above process, the metal thin film layer can be destroyed in the form of an image by a heat source such as a thermal head or a laser beam, and a colored image can be formed on the colored layer accordingly.

The present invention will be explained below with reference to the drawings.

An example of this is as shown in FIG. 1, on a support 1 (a two-layer color layer 2, a metal thin film layer 3, and a protective layer 4), and as shown in FIG. 5, a layer in which a colored layer 2, an adhesive layer 6, a metal thin film layer 3, and a protective layer 4 are sequentially laminated.

Each of the above layers will be specifically explained.

The support IE is mechanically strong and flexible, and can be made of polyethylene terephthalate film or other plastics,
Examples include coated paper, art paper, laminated paper, glass, metal, etc. The colored layer 2 is a layer that appears as an image by imagewise heating, and contains ethyl cellulose, hydroxyethyl cellulose, cellulose acetate gropionate,
Cellulose derivatives such as cellulose acetate, styrene resins or styrene copolymer resins such as polystyrene, poly-α-methylstyrene, acrylic resins or methacrylates such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate. Resin alone or copolymer resin, rosin, rosin-modified maleic acid resin, rosin-modified phenolic resin, rosin ester resin such as polymerized rosin, polyvinyl acetate resin, coumarone resin, vinyltoluene resin, vinyl chloride resin, polyester resin, polyurethane resin , to a binder such as butyral resin, various pigments or dyes are added depending on the color to be colored, and if necessary, plasticizers, stabilizers,
Applying methods such as the usual gravure method, roll method, knife method, offset method, etc. or printing using a colored paint or ink made by adding wax, curing agent, and dispersant and then sufficiently kneading with a solvent or diluent. Depending on the method, a desired portion can be formed.

The metal thin film layer 3 is made of To, Sn, In, Am
, Bi, Pb.

A metal such as Zn, an alloy thereof, or a compound of the above metals such as Te/carbide can be formed on the colored layer 2 provided on the support 1 by a vacuum evaporation method, a sputtering method, a plating method, etc. . This layer preferably has a low melting point in order to function as a heat-sensitive recording layer. The thickness of this layer is about 100A to 1 micron, preferably about 500 to 1000A.

The protective layer 4 is provided to physically protect the metal thin film layer, and if necessary, it is possible to use a mixture of resins such as polyester resin, polyurethane resin, acrylic resin, etc., but it does not have water resistance, sweat resistance, In order to ensure washing resistance and chemical resistance, it is desirable to use polyester resin or polyurethane resin in an amount of at least 50% by weight of all the resins in the protective layer. It is also possible to add a crosslinking agent such as melamine resin, epoxy resin, polyisocyanate type, or aziridine type to the protective layer in order to further improve the water resistance, chemical resistance, etc. of the polyester resin or polyurethane resin.

Next, the adhesive layer 6 used in the present invention is a thermoplastic polymer, and has improved solvent resistance (the colored layer is softened by penetration of the solvent during coating of the solvent-based protective layer, and the whiteness of the metal thin film layer is reduced). ), thermoplasticity improves thermal recording sensitivity and contributes to improvements in water resistance, sweat resistance, washing resistance, plasticizer resistance, etc. Specifically,
Polystyrene, acrylic (PMMA, etc.) acetelglobil cellulose (CAP) to obtain a silvery white background
, acetyl cellulose (CAB), vinyl chloride-vinyl acetate copolymer, nitrocellulose, and cellulose acetate can be cited as materials for obtaining a golden background.

The exact cause of this phenomenon in which the background color tone differs depending on the polymer is unknown, but many polymers that turn golden yellow have the property of yellowing when exposed to heat or light, and it is thought that this is due to the heating during vapor deposition. Conceivable.

In particular, in the present invention, a barrier single-layer resin exhibiting a silvery white background is preferably used because it provides contrast with the recorded characters (black) and provides a clean appearance.

In order to control thermoplasticity, addition of starifiers, waxes, etc. may also be considered. It should be noted that the use of a hardening agent that inhibits thermoplasticity is undesirable because it lowers the thermal recording sensitivity.

Next, the under layer 5 is provided between the support and the colored layer to improve adhesion between the two, and can be selected from many conventionally known polymers without any special restrictions. For example, aqueous polyvinyl alcohol, starch, urethane resin, solvent-soluble polyester, acrylic resin, etc. are used.

Next, regarding pigments, they are contained in at least one of the under layer, colored layer, and adhesive layer, creating appropriate unevenness in the coating layer, which is also reflected in the metal thin film layer, causing diffused reflection of light. Increase. Furthermore, the contrast of the metal thin film is increased, and a clear recorded image can be obtained. Furthermore, although the reason is unknown, it is also recognized that thermal recording sensitivity is improved.

The particle size of the pigment actually used is preferably 5 μm, with an average diameter of 1 to 10 μm measured by a Coulter counter.
It is considered that the type does not matter as long as it is a counterfeit pigment. When the particle size is less than 1 μm, there is no effect of improving the whiteness, and on the other hand, when the particle size exceeds 10 pys, it becomes impossible to record fine lines sufficiently in recording with a thermal head.

Other known white inorganic pigments, in which silica is usually used, can also be used if the particle size is adjusted.Also, various organic pigments made by controlling the particle size. Specific examples include silica, calcium carbonate, barium sulfate, clay, activated clay zeolite, inorganic white pigments such as talc, cross-linked polystyrene, polyethylene beads,
Examples include organic transparent or white pigments such as silicone beads, and colored pigments such as red lead, ultramarine blue, titanium yellow, red yellow lead, and plastic type fluorescent pigments.

Note that recording on the recording medium of the present invention is performed using heating means such as a thermal head, laser light, flash light, or the like.

The present invention can be carried out by providing a magnetic recording layer on the back surface of the support, or by providing an adhesive layer and a separator to form a label, as described below.

Particularly in the latter case, the adhesives used as adhesives include those used in the emulsion type of acrylic ester resin, ethylene/vinyl acetate copolymer resin, natural rubber, synthetic rubber, polyacrylic ester, and polyvinyl alcohol. When forming the adhesive layer and attaching the separator, either apply the adhesive to the back of the support and attach it to the separator using dry lamination, or apply the adhesive to the separator. , bonding with the back side of the support (this is done from the second step).

As the separator, there may be used a support such as paper coated and impregnated with a release agent such as a silicone resin or a fluorine-based resin, or a plastic tape made of a silicone resin or a fluorine-based resin having an excellent release effect.

In addition, in the present invention, if a temperature-sensitive adhesive is used in the adhesive layer, it is possible to carry out the process without using a separator.

(Example) Examples will be described below.

Example 1 Thickness: 188. A heat-sensitive recording medium was obtained by sequentially laminating the following layers on a milky white polyethylene terephthalate film of l'@ by coating or the like.

(1) Colored layer: The following composition was dried at 110°C.
It was applied at a coating amount of 4, 2, 9/ya''.

(2) Drying temperature 110°C for adhesive layer 2 or less composition
It was applied at a coating amount of 1, 7, 9/rlp.

(3) Metal thin film layer: Tin was deposited by vacuum evaporation so that the film thickness was 60 OA when measured by a film thickness measurement method using a crystal resonator.

(4) For those with a protective layer composition of 2 or less, drying temperature 110
It was applied at a coating amount of 2.1 fi/- at °C.

The produced thermosensitive recording medium was heated with a pulse width of 2,
When an image was recorded at an applied energy of 0.61 5 maee, a clear black image was obtained against a silvery white background. When the density was measured using a Macbeth Densitometer RD-914 visual filter, the background part was O, D,
The OoD of the recorded portion was 1.32, indicating good contrast.

Further, the following tests were conducted on the obtained recorded images.

1) Light resistance was examined using a fade meter after 6 hours of exposure.

2) Water resistance and chemical resistance were examined by immersing in water at 20°C for 24 hours.

3) After dropping a 50% aqueous solution of ethanol onto the recording surface, the writing was wiped off after 2 minutes and chemical resistance was examined.

4) Cottonseed oil was applied and left at 20°C for 24 hours to examine oil resistance.

5) Apply a weight of 100g to the plastic eraser 2
The hardener resistance was examined after being left at 0"C for 24 hours.

As a result, the original recording density could be maintained.

Further, after the obtained recorded image was left for 24 hours at 60°C, 6s t4 RH, the skin remained the same as the original, confirming that the image had sufficient heat resistance.

Example 2 A heat-sensitive recording material was obtained by coating a milky white polyethylene terephthalate film with a thickness of 188 Pm with the following layers by coating or the like.

(1) Colored layer: The following composition was dried at 110°C.
(2) Metal thin film layer coated with S coating amount of 5.5 fl/metre: A metal thin film layer was provided in the same manner as in Example 1.

(3) Protective layer: A protective layer similar to that in Example 1 was provided.

When recording was performed on the produced heat-sensitive recording medium in the same manner as in Example 1, the background density was 0. D, 0.36 for the gold-white skin area, 0.36. A clear black image with a recording density of 1.27 was obtained. In addition, Example 1 also showed chemical resistance to light, water resistance, oil resistance, plasticizer resistance, and heat resistance.
Similar results were obtained.

Example 3 The following layers were successively laminated by coating or the like on a high-quality paper of 165 gm to obtain a heat-sensitive recording material.

(1) Dry the under layer with a composition of 2 or less at a temperature of 1
Coating was carried out at 10° C. with a coating amount of 5.211/shoulder f.

(2) Colored layer: A layer having the same composition as in Example 2 was coated at a drying temperature of 110°C and a coating weight of s, yg/.

(3) Adhesive layer: The following composition was coated at a drying temperature of 110°C and a coating weight of 2.0777.

(4) Metal thin layer: Indium was deposited using a vacuum evaporation method to a film thickness of 550 Å as measured by a film thickness measurement method using a crystal resonator.

(5) Protective layer: Drying temperature: 100° C. Coating amount: 359/recording was performed on the prepared thermal recording medium using a thermal head with a pulse, Il, width of 2.5 m5 ec, and applied energy of 0.45 W. O, D, 0.35q) O, D against silvery white skin.

A clear black image of 1.36 was obtained. Also, similar results to those of Example 1 were obtained regarding light resistance, chemical resistance, water resistance, oil resistance, plasticity resistance, and heat resistance.

Example 4 A magnetic coating with high coercive force shown below was applied to the back surface of the support constituting the recording medium obtained in Example 1 to a coating thickness of 15 μm to form a magnetic recording layer. A thermosensitive recording medium of the invention was created.

When recording was performed on the obtained thermosensitive recording medium in the same manner as in Example 1, a clear recorded image with a background density of 0.36 and a recorded density of 1°27 was obtained.

Furthermore, when this heat-sensitive recording medium was made into a card and applied to a cash ticket vending machine having a heat-sensitive recording structure, and predetermined magnetic information was written and read and the remaining amount was displayed on the heat-sensitive recording surface, there was no problem in implementation. was confirmed.

Example 5 The adhesive side of Sebaretame coated with an adhesive made of ethylene-vinyl acetate copolymer resin was attached to the back side of the support constituting the recording medium obtained in Example 1, and a label of the present invention was prepared. A thermosensitive recording medium was created.

When the obtained thermal recording was performed, the skin density was 0, D, 0.
．． 51 and the recording density is 0. D. A clear recorded image of 1.30 was obtained.

In addition, the heat-sensitive recording medium for labels can be used as a POS (Pr1nt
When used as a display label for the ofSadθB) system, it had sufficient performance for practical use.

(Effects of the Invention) Since the present invention has the above configuration, it is possible to provide a heat-sensitive recording material having excellent heat resistance, light resistance, and chemical resistance.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are both cross-sectional views showing examples of thermosensitive recording media obtained by the present invention. 1: Support 2: Colored layer 3: Metal thin film layer 4: Protective layer
5: Under layer 6: Adhesive layer agent Takeuchi, patent attorney
Mamoru No. 1 Chrysanthemum No. 2

Claims (5)

[Claims] (1) The essential components include a support, a colored layer provided sequentially outward on one side of the support, a metal thin film layer, and a protective layer, and an under layer and a colored layer between the support and the colored layer. The adhesive layer between the metal thin film layers is an optional component, and the layered product contains a pigment having an average particle size of 1 to 10 μm in one or more of the colored layer, the under layer, and the adhesive layer. A heat-sensitive recording medium. (2) The heat-sensitive recording according to claim 1, characterized in that it is formed by sequentially laminating a colored layer containing a pigment with an average particle size of 1 to 10 μm, a metal thin film layer, and a protective layer on a support. Medium. (3) A heat-sensitive recording medium in which a colored layer, an adhesive layer mainly composed of a thermoplastic polymer, a metal thin film layer, and a protective layer are sequentially laminated on a support, wherein at least one of the colored layer and adhesive layer is laminated in sequence.
The heat-sensitive recording medium according to claim 1, characterized in that each layer contains a pigment having an average particle size of 1 to 10 μm. (4) A heat-sensitive recording medium comprising an under layer, a colored layer, a metal thin film layer, and a protective layer sequentially laminated on a support, wherein at least one of the under layer and the colored layer has an average particle size. 1
The heat-sensitive recording medium according to claim 1, characterized in that it contains a pigment of ~10 μm. (5) A thermosensitive recording medium comprising an under layer, a colored layer, an adhesive layer mainly composed of a thermoplastic polymer, a metal thin film layer, and a protective layer laminated on a support in this order, the under layer, the colored layer, At least one layer of the adhesive layer has an average particle size of 1 to 1.
The heat-sensitive recording medium according to claim 1, characterized in that it contains a pigment of 0 μm.