JPH02116588A - Thermal recording medium - Google Patents

Abstract

PURPOSE:To obtain a heat-sensitive material superior in resistance to heat, light, chemicals, and wear by a method wherein a substrate, a coloring layer, a metal film layer, and a protective layer are successively provided as essential components, and a layer adjacent to the metal film layer contains a polyolefine resin as a main ingredient. CONSTITUTION:On one side of a substrate 1, a coloring layer 2, a metal film layer 3, and a protective layer 4 are successively laminated. As optional components, an adhesive layer 6 is provided between the coloring layer 2 and the metal film layer 3, and an adhesive layer 7 is provided between the metal film layer 3 and the protective layer 4. Additionally, as an optional component, an under layer 5 is formed between the substrate 1 and the coloring layer 2. At least one of the layers adjacent to the metal film layer 3 contains a polyolefine resin as a main ingredient. The layers adjacent to the metal film layer 3 are the coloring layer 2, the adhesive layer 6, the adhesive layer 7, and the protective layer 4. As the polyolefine resin, polyethylene, polypropylene, vinyl acetate, acrylic acid, methacrylic acid, and others are applicable. In this manner, a thermal recording medium superior in recording characteristics and resistance to heat, light, chemicals, and wear is obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is used for computer boot/boot records, facsimile machines, tickets, cards, etc., and is a thermosensitive record that records using physical changes caused by heating. It's about the medium.

(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 for use in the above-mentioned heat-sensitive recording method, which can produce colored images with strong heat resistance, light resistance, chemical resistance, and abrasion resistance.

(Means for Solving the Problems) (Function) The present invention was developed as a result of intensive studies to solve the various problems mentioned above, and the outline thereof 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,
An under layer between the support and the colored layer, an adhesive layer (I) between the colored layer and the metal thin film layer, and an adhesion N(n) between the metal thin film layer and the protective layer are optional constituent elements, and the metal thin film The heat-sensitive recording medium is characterized in that at least one layer adjacent to the layer contains a polyolefin resin as a main component.

Such a heat-sensitive recording medium is capable of destroying a metal thin film layer in the form of an image using a heat source such as a thermal head, laser light, or flash light, and correspondingly forming a colored image on a colored layer.

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

The heat-sensitive recording medium of the present invention is composed of a combination of a support 1, a colored layer 2, a metal thin film layer 3, a protective layer 4, an under layer 5, an adhesive layer (■) 6, and an adhesive layer (■) 7, Examples of layer configurations are shown in FIGS. 1-5.

That is, FIG. 1 shows the basic structure consisting of essential components constituting the heat-sensitive recording medium of the present invention, in which a colored layer 2, a metal thin film N3, and a protective layer 4 are sequentially laminated on one side of a support 1. Further, FIG. 2 has a configuration in which, in addition to the basic configuration of FIG. 1, an optional component, adhesive III (I) 6, is provided between the colored layer 2 and the metal thin film layer 3. Further, FIG. 3 has a configuration in which, in addition to the basic configuration of FIG. 1, an optional component adhesive layer (■) 7 is provided between the metal thin film layer 3 and the protective layer 4. Further, FIG. 4 has a configuration in which, in addition to the basic configuration of FIG. 1, optional constituent elements, an adhesive layer (I) and an adhesive layer (II), are provided. 5 shows a structure in which, in addition to the structure shown in FIG. 4, an optional underlayer 5 is provided between the support 1 and the colored layer 2.

The present invention is characterized in that at least one layer adjacent to the metal thin film N3 contains a polyolefin resin as a main component. Here, the colored layer 2, the adhesive layer (I) 6, the adhesive layer (■) 7, and the protective layer 4 are listed as the layers adjacent to the metal thin film layer 3 based on the combination of layers.

Polyolefin resin has excellent adhesion to metals,
In addition, the present inventors selected binder resins from among many binder resins because they have appropriate thermoplasticity, such as homopolymers such as polyethylene and polypropylene, vinyl acetate, acrylic acid, methacrylic acid, maleic anhydride, A two-component system or a three-component system consisting of monomers such as acrylic esters and methacrylic esters and ethylene or propylene.
Component-based copolymers and the like are applicable to the present invention and are applied by coating and printing methods as true-melt, solvent-based or water-based paints. More specifically, copolymers of ethylene or propylene and acrylic acid or methacrylic acid are particularly suitable for the present invention. This copolymer is used with the acid component left unneutralized or partially or completely neutralized with an alkali component such as sodium hydroxide, ammonia, or an organic amine, and then dissolved or dispersed in water or a solvent. . Note that the polyolefin resin contained in at least one layer adjacent to the metal thin film layer 3 must account for 50% by weight or more of the total solid content in that layer.

Next, each layer will be specifically explained.

Examples of the support 1 include mechanically strong and flexible polyethylene terephthalate film and other plastics, coated paper, art paper, laminated paper, glass, metal, and the like. The colored layer 2 is a layer that appears as an image by imagewise heating, and is made of cellulose derivatives such as ethyl cellulose, hydroxyethyl cellulose, cellulose acetate propionate, and cellulose acetate, styrene resins such as polystyrene, poly-α-methylstyrene, or styrene copolymer. Resin, single or copolymer resin of acrylic resin or methacrylic resin such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate, rosin, rosin-modified maleic acid resin, rosin-modified phenolic resin, polymerized rosin Various pigments or dyes are added to binders such as rosin ester resins, polyvinyl acetate resins, coumaron resins, vinyl toluene resins, vinyl chloride resins, polyester resins, polyurethane resins, butyral resins, etc., depending on the color to be colored. , Further, if necessary, after adding a plasticizer, stabilizer, wax, curing agent, and dispersant, thoroughly knead with a solvent or diluent to prepare a colored paint or ink,
This can be done using the normal gravure method, roll method, knife method,
By coating methods such as offset method or printing method,
Form it on the desired part.

The metal thin film layer 3 is made of Te, Sn, Int AL Bi,
Metals such as Pb and Zn, alloys thereof, or compounds of the above metals such as Te and carbide can be formed on the colored layer 2 provided on the support 1 by vacuum evaporation, sputtering, plating, etc. can.

This layer preferably has a low melting point in order to function as a heat-sensitive recording layer. Also, the thickness of this layer is 100
The size is about 1 micron, preferably about 500 to 1000 people.

The protective layer 4 is for physically and chemically protecting the metal thin film layer, and is made of a binder such as polyester resin, polyurethane resin, acrylic resin, or epoxy resin, and wax, pigment, hardening agent, etc. as necessary. Provided in addition. Further, it is also extremely effective to use an ultraviolet curable resin in the present invention. Examples of the ultraviolet curable resin include those that form an ultraviolet curable film by utilizing a photoradical polymerization reaction of a vinyl-containing compound. This type is composed of (I) a monomer or oligomer containing a vinyl group, and (2) a photopolymerization initiator. Monomers for (I) include various mono-substituted ethylenes and 1,1-di-substituted ethylenes, and oligomers used include various acrylic oligomers such as unsaturated polyesters, polyol acrylates, oligoester acrylates, and urethane acrylates. be done.

Examples of the photopolymerization initiator (2) include benzoin alkyl ether, acetophenone derivatives, benzophenone, benzyl, and alkylamino-substituted benzophenones.

Further, an ultraviolet curable resin that utilizes a photo-ring-opening polymerization system of an epoxy group compound can also be used. This is a method in which a substance that generates a Lewis acid upon irradiation with light is mixed with an epoxy resin, causing cationic polymerization by a Lewis acid catalyst to cause curing. As the photoinitiator, aromatic diazonium salts of Lewis acids, aromatic halonium salts of Lewis acids, aromatic sulfonium salts of Lewis acids, etc. are used. By applying these ultraviolet curable resins to the protective layer 4, the heat-sensitive recording medium of the present invention can have excellent properties not only in heat resistance, light resistance, and chemical resistance, but also in abrasion resistance.

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.

The adhesive layer (■) 6 is located between the colored layer 2 and the metal thin film layer 3 to improve the adhesion between them, and also improves the thermal recording sensitivity by promoting destruction of the metal thin film layer 3 during thermal recording. Polymers with appropriate thermoplasticity are used in order to provide an improving function. Specifically, polystyrene, acrylic resins such as polymethyl methacrylate (PMMA), cellulose acetate propionate (CAP)
), vinyl chloride-vinyl acetate copolymers, polyester resins, polyurethane resins, epoxy resins, and the like.

Addition of plasticizers, waxes, etc. may also be considered to control thermoplasticity. Note that the use of a curing agent that significantly inhibits thermoplasticity is undesirable because it lowers thermal recording sensitivity.

The adhesive layer (■) 7 is located between the metal thin film N3 and the protective layer 4 and improves the adhesion between the two, and is also required to physically and chemically protect the metal thin film N3 together with the protective layer 4. be done. Considering chemical resistance, suitable resins are polyester resins, polyurethane resins, acrylic resins, etc., and crosslinking agents such as melamine resins, epoxy resins, polyisocyanate resins, and aziridine resins may also be added. It is possible.

Further, in the heat-sensitive recording medium of the present invention, various pigments and additives may be used in each layer except the above-mentioned metal thin film layer, if necessary. In particular, a particle size analyzer (
Average particle size l~10μm by Coulter Counter)
Preferably, by containing a pigment of 1 to 5 μm to create appropriate irregularities in the coating layer, it also acts on the metal thin film layer to reduce glare on the metal thin film layer, making the recorded image easier to see. Become. Furthermore, although the reason is unknown, it has also been recognized to have the effect of improving thermal recording sensitivity. When the particle size is less than 1 μm, there is no effect of improving whiteness, and on the other hand, when the particle size exceeds 10 μm, sufficient recording cannot be achieved by a thermal head.

Specifically, silica is commonly used, but other known white inorganic pigments can also be used as long as the particle size is adjusted. Furthermore, various organic pigments made with controlled particle sizes can also be used. Specifically, inorganic white pigments such as silica, calcium carbonate, barium sulfate, clay, activated clay zeolite, and talc; organic transparent or white pigments such as crosslinked polystyrene, polyethylene beads, and silicone beads;
Examples include coloring pigments such as red lead, ultramarine blue, titanium yellow, red yellow lead, and plastic type fluorescent pigments.

Note that recording on the thermosensitive 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 side of the support, or by providing an adhesive layer and a separator to form a label.

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. , by bonding it to the back side of the support.

As the separator, a support such as paper coated with a mold release agent such as a silicone resin or a fluorine resin, or a plastic tape having an excellent mold release effect such as a silicone resin or a fluorine resin may be used.

In addition, in the present invention, if a temperature-sensitive adhesive is used in the adhesive layer, the present invention can be carried out without a separator.

(Example) Examples will be described below.

Example 1 A heat-sensitive recording medium of the present invention was obtained by sequentially laminating the following layers on a support made of a milky white polyethylene terephthalate film having a thickness of 188 μm.

fl) Colored layer: one with the following composition, dried at 110°C,
It was applied at a coating amount of 4.0 g/m''.

(2) Metal thin film layer: Tin was deposited by vacuum evaporation to a film thickness of 600 mm as measured by a film thickness measurement method using a crystal oscillator.

(3) Protective layer: After coating the following composition, the protective layer was cured by irradiating ultraviolet rays for 5 seconds with a 2000W high-pressure mercury lamp. The coating amount was 2.3 g/m2.

(2) Adhesive layer (I) The composition of the lower two sides is dried at a temperature of 11
Coating was carried out at 0°C at a coating weight of 1.3 g/m''.

Example 2 A heat-sensitive recording medium of the present invention was obtained by sequentially laminating the following layers on a support made of a milky white polyethylene terephthalate film having a thickness of 188 μm.

(I) Colored layer with a composition of 2 or less at a drying temperature of 110°C.
The coating amount was 3.5 g/m''.

1 g of toluene (3) Metal thin film layer: A metal thin film layer was provided in the same manner as in Example 1.

(4) Protection N: A protective layer was provided in the same manner as in Example 1.

Example 3 The following layers were sequentially laminated on a support made of a milky white polyethylene terephthalate film having a thickness of 188 μm to obtain a heat-sensitive recording medium of the present invention.

(Colored layer I1: A colored layer was provided in the same manner as in Example 2.

(2) Metal thin film layer: A metal thin film layer was provided in the same manner as in Example 1.

(3) Adhesive layer (■) The composition on the bottom two sides is dried at a temperature of 12
Coating was carried out at 0°C in a coating amount of 2.8 g/m2.

(4) The composition below the two protective layers is dried at a temperature of 110°C.
The coating amount was 2.0 g/m''.

A heat-sensitive recording medium of the present invention was obtained by sequentially laminating the following layers on a support made of Yubo FPG 200).

fl) Colored layer: A colored layer was provided in the same manner as in Example 2.

(2) Adhesive layer (I): Adhesive layer (I) in the same manner as in Example 2.
) was established.

(3) Metal thin film layer: A metal thin film layer was provided in the same manner as in Example 1.

(4) Adhesive layer (■): The following composition is dried at a temperature of 11
Coating was carried out at 0°C and at a coating ff of 12.7 g/m2.

Example 4 200μ thick white synthetic paper (Oji Yuka Synthetic Gisha (5)) Protective layer: A protective layer was provided in the same manner as in Example 3.

Example 5 The following layers were sequentially laminated on a support made of high-quality paper with a scale of 165 g/m" to obtain a heat-sensitive recording medium of the present invention.

(I) Under layer: The following composition is dried at a temperature of 120
It was applied at a coating weight of 4.1 g/m''.

A comparative heat-sensitive recording medium was prepared in the same manner as in Example 1, except that polyvinyl alcohol was used instead of polyvinyl alcohol.

Comparative Example 2 A comparative thermosensitive recording medium was produced in the same manner as in Example 2 except that the adhesive layer (I) in Example 2 was replaced with the following.

(2) Colored layer, adhesive layer (I), metal thin film layer, adhesive layer (n
) and protective layer: all the same as in Example 4.

Comparative Example 1 Water-based polyolefin in the colored layer in Example 1 Comparative Example 3 A comparative heat-sensitive recording medium was prepared in the same manner as in Example 3 except that the adhesive layer (n) in Example 3 was replaced with the following. did.

The following characteristic evaluations were performed on the thermosensitive recording media produced in Examples 1 to 5 and Comparative Examples 1 to 3 above.

(I) Recording Characteristics Image recording was performed using a thermal head with a pulse width of 2.5 m5ec and an applied energy of 0.6 W. Recording density and background density were measured using a Macbeth densitometer RD-914 visual filter.

(2) Light resistance After exposure for 6 hours using a fade meter, the density of the recorded area and the background was similarly measured using a Macbeth densitometer.

(3) Water resistance It was immersed in water at 20°C for 3 days to examine its water resistance.

(4) Alcohol resistance A 50% aqueous solution of ethanol was added dropwise and 2 minutes later, it was wiped off to examine the alcohol resistance.

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

(6) Plasticizer resistance A plastic eraser (Tombo Mono) was subjected to a load of 100 g and left at 20° C. for 24 hours to examine its plasticizer resistance.

(7) Heat resistance It was placed in a dryer at 100°C for 10 minutes to examine its heat resistance.

(8) Wear resistance The wear resistance was examined by passing through the automatic ticket gate 2000 times in the same direction.

These results are shown in Table 1 using a three-level evaluation of ○△x. From the results in Table 1, it was confirmed that the heat-sensitive recording medium of the present invention had excellent characteristics.

(Effects of the Invention) Since the present invention has the above configuration, recording characteristics, heat resistance,
A heat-sensitive recording medium with excellent light resistance, chemical resistance, and abrasion resistance can be provided.

[Brief explanation of the drawing]

1 to 5 are sectional views showing the layer structure of an example of a heat-sensitive recording medium obtained according to the present invention. DESCRIPTION OF SYMBOLS 1... Support, 2... Colored layer, 3... Metal thin film layer, 4... Protective layer, 5... Under layer, 6... Adhesive layer (I), 7... Adhesive layer (If) Patent applicant Tomegawa Paper Mills Co., Ltd.

Claims (1)

[Claims] The essential components include a support, a colored layer, a metal thin film layer, and a protective layer provided sequentially outward on one side of the support, an under layer between the support and the colored layer, a colored layer, and a metal thin film layer. The adhesive layer (I) between the metal thin film layer and the protective layer (II) is an optional component, and at least one layer adjacent to the metal thin film layer is mainly made of polyolefin resin. A heat-sensitive recording medium characterized by containing as a component.