JP3090484B2 - Reversible thermosensitive recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible thermosensitive recording material for recording and erasing by utilizing a reversible change in transparency with temperature.

[0002]

2. Description of the Related Art In recent years, a reversible thermosensitive recording material which can form a temporary image and erase the image when it becomes unnecessary has been attracting attention. As a typical example, a resin material such as a vinyl chloride-vinyl acetate copolymer having a low glass transition temperature (Tg) of from 50 to 60 ° C. to less than 80 ° C. is contained in a resin matrix such as a higher fatty acid. There is known a reversible thermosensitive recording material having a thermosensitive layer in which various organic low-molecular substances are dispersed (JP-A-54-119377, JP-A-55-154198, etc.).

Further, reversible thermosensitive recording materials provided with a protective layer on the heat-sensitive layer to protect the heat-sensitive layer are also known (JP-A-1-33781, JP-A-2-566, JP-A-63-1988). -221087
In addition, in order to protect the heat-sensitive layer from the monomer components and the solvent of the protective layer liquid, an intermediate layer using an alcohol-based solvent is provided between the protective layer and the heat-sensitive layer. Provided reversible thermosensitive recording material is also known (JP-A-1-33781
Publication).

However, when the reversible thermosensitive recording material is heated with a heating element such as a thermal head for a short time, if the energy is low, the opacity of the image portion is low in image formation, and the erasure is low in image erasure. It was a drawback that it was difficult to do.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks and can form an image with high turbidity even when heating with a low energy for a short time using a heating element such as a thermal head. Another object of the present invention is to provide a high-contrast reversible thermosensitive recording material from which an image can be erased.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a semiconductor device comprising the steps of:
In a reversible thermosensitive recording material comprising a resin base material and a heat-sensitive layer whose main component is a low-molecular organic substance dispersed in the resin base material and whose temperature-dependent transparency reversibly changes, a support and a heat-sensitive recording material are used. A heat insulating layer is provided between the layers, or a heat insulating support is used as the support.

That is, the reversible thermosensitive recording material of the present invention has a heat-insulating layer or a heat-insulating support, and the heat-insulating layer or the heat-insulating support does not allow a small amount of heat to escape out of the heat-sensitive layer.
Since it can be kept, the sensitivity of the heat-sensitive layer can be improved. Further, unlike a normal thermal paper, the reversible thermosensitive recording material of the present invention has a temperature range in which it becomes transparent as described later (T _{2 in} FIG. 1). This makes it difficult for the heat of the thermal head to escape, so that the entire recording layer including the width direction and the depth direction can have a uniform temperature, and a uniform transparent state can be obtained.

As the heat insulating layer, the following can be used, but it is not limited to them. 1. Chemical compound insulation polyurethane foam, polystyrene foam, vinyl chloride foam, plastic corrugate, etc. 2. Fine hollow sphere particles dispersed in a heat insulating layer. Examples of the fine hollow particles include the following. 1) Expanded heat-expandable microspheres Hollow particles having a capsule wall made of a thermoplastic material and containing a volatile expanding agent inside the particles Thermoplastic material: vinylidene chloride-acrylonitrile copolymer Merging etc. Volatile swelling agents: n-butane, isobutane, neopentane petroleum ether and the like. Thermal conductivity = 0.02 to 0.06 W / mK Example: Micropearl manufactured by Matsumoto Yushi Co., Ltd., manufactured by Chemanode E
xpamcel 2) Glass fine hollow sphere powder Microsphere of borosilicate glass Thermal conductivity = 0.11 W / m · K Example: Microcell M manufactured by Grappavel 3) Aluminosilicate micro hollow sphere powder Low foam injection molding Premix for standard and standard injection molds Thermal conductivity = 0.007 W / mK Example: Fillite manufactured by Nippon Philite Co. The thickness of the heat insulation layer is preferably about 0.1 to 50 m, more preferably 0.2 to 20 m. .

As the heat-insulating support, synthetic paper can be used, and among synthetic papers, those containing microvoids produced by the internal paper-making method are preferable.

The reversible thermosensitive recording material of the present invention utilizes the change in transparency (transparent state, cloudy opaque state) as described above. The difference between this transparent state and cloudy opaque state is presumed as follows. . That is, in the case of (I) transparent, the particles of the organic low-molecular substance dispersed in the resin base material are composed of large particles of the organic low-molecular substance, and the light incident from one side is not scattered and is opposite. (II) In the case of white turbidity, the particles of the organic low molecular weight substance are composed of polycrystals in which fine crystals of the organic low molecular weight substance are aggregated, and the crystal axis of each crystal Is oriented in various directions, so that light incident from one side is refracted many times at the interface between the crystals of the organic low-molecular substance particles, and is scattered, so that it appears white.

In FIG. 1 (representing a change in transparency due to heat), a heat-sensitive layer mainly composed of a resin base material and an organic low-molecular substance dispersed in the resin base material is, for example, T _0.
At the following room temperature, it is cloudy and opaque. This became clear when heated to a temperature T _2, which remains also clear again returned to the normal temperature of T ₀ or less in this state. This may be because the crystalline low-molecular organic material before reaching the T ₀ or less from the temperature T ₂ is between the single crystal from a polycrystalline via a semi-molten state grows. Further T ₃
Heating to the above temperature results in a translucent state intermediate between the maximum transparency and the maximum opacity. Next, when the temperature is lowered, the state returns to the original cloudy and opaque state without taking the transparent state again. This after low-molecular organic material is melted at a temperature T ₃ or more, presumably because the polycrystals precipitated by being cooled. When this opaque state is heated to a temperature between T _{1 and} T ₂ and then cooled to room temperature, that is, a temperature equal to or lower than T ₀ , an intermediate state between transparent and opaque can be obtained. Also, by returning to room temperature After heating to be again T ₃ or more temperature which became clear at the normal temperature, the flow returns to cloudy opaque state again. That is, both opaque and transparent forms at room temperature and intermediate states thereof can be taken.

Therefore, the heat-sensitive layer can be selectively heated by selectively applying heat to form a cloudy image on a transparent ground and a transparent image on a cloudy ground, and the change can be repeated many times. It is possible. If a colored sheet is arranged on the back of such a heat-sensitive layer, a color image of the colored sheet on a white background or a white image on a colored background of the colored sheet can be formed. Further, when projected by an OHP (overhead projector) or the like, the cloudy portion becomes a dark portion, the transparent portion transmits light, and becomes a bright portion on the screen.

In order to prepare the reversible thermosensitive recording material according to the present invention, generally, (1) a solution in which two components of a resin base material and an organic low-molecular substance are dissolved, or (2) a solution of the resin base material (an organic solvent is used as a solvent) A dispersion in which at least one of the low-molecular substances is not dissolved) is applied to a support such as a plastic film, a glass plate, or a metal plate, and dried by applying a dispersion liquid in which organic low-molecular substances are dispersed in fine particles. May be formed.

The solvent for forming the heat-sensitive layer or the heat-sensitive recording material can be variously selected depending on the types of the resin base material and the organic low-molecular substance. Examples thereof include tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, chloroform, carbon tetrachloride, ethanol, toluene, and the like. Benzene and the like can be mentioned. In addition, of course, when a dispersion is used,
Even when a solution is used, in the heat-sensitive layer obtained, the organic low-molecular substance is precipitated as fine particles and exists in a dispersed state.

The resin base material used for the heat-sensitive layer is a material which forms a layer in which organic low-molecular substances are uniformly dispersed and held, and which affects the transparency at the time of maximum transparency. For this reason, the resin base material is preferably a resin having good transparency, mechanical stability, and good film formability.

Such resins include polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride- Vinyl chloride copolymer such as acrylate copolymer; polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride copolymer such as vinylidene chloride-acrylonitrile copolymer; polyester; polyamide; polyacrylate or poly Methacrylate or acrylate-methacrylate copolymer; silicone resin, and the like. These may be used alone or as a mixture of two or more.

On the other hand, any organic low-molecular substance may be used as long as it changes from polycrystal to single crystal by heat in the recording layer, and generally, a substance having a melting point of about 30 to 200 ° C., preferably about 50 to 150 ° C. is used. . Such organic low molecular weight substances include alkanol; alkane diol; halogen alkanol or halogen alkane diol; alkylamine; alkane; alkene; alkyne; halogen alkane; halogen alkene; halogen alkyne; cycloalkane; cycloalkene; cycloalkyne; Unsaturated mono- or dicarboxylic acids or their esters, amides or ammonium salts; saturated or unsaturated halogen fatty acids or their esters, amides or ammonium salts; allylcarboxylic acids or their esters, amides or ammonium salts; Esters, amides or ammonium salts thereof; thioalcohols; thiocarboxylic acids or their esters, amines or ammonium salts; Carboxylic acid esters, and the like. These may be used alone or in combination of two or more. The carbon number of these compounds is 10 to 60, preferably 10 to 38, particularly preferably 10 to 30. The alcohol group in the ester may be saturated or non-saturated, and may be halogen-substituted. In any case, the organic low-molecular substance is at least one kind of oxygen, nitrogen, sulfur and halogen in the molecule, for example, -OH, -COOH, -CONH
-, - COOR, -NH -, - NH 2, -S -, - SS -, - O-, is preferably a compound containing a halogen and the like.

More specifically, these compounds include higher fatty acids such as lauric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, stearic acid, behenic acid, nonadecanoic acid, araginic acid and oleic acid; methyl stearate Esters of higher fatty acids such as tetradecyl stearate, octadecyl stearate, octadecyl laurate, tetradecyl palmitate, dodecyl behenate; And ether or thioether. Among them, in the present invention, higher fatty acids, particularly higher fatty acids having 16 or more carbon atoms such as palmitic acid, stearic acid, behenic acid, and lignoceric acid are preferable, and higher fatty acids having 16 to 24 carbon atoms are more preferable.

In order to widen the range of temperatures at which transparency can be obtained, the organic low-molecular substance described in this specification may be appropriately combined, or such an organic low-molecular substance may be combined with another material having a different melting point. . These are disclosed, for example, in JP-A-63-3
No. 9378, JP-A-63-130380 and Japanese Patent Application No. 63-14
No. 754, Japanese Patent Application No. 1-140109, and the like, but are not limited thereto. The ratio between the organic low-molecular substance and the resin base material in the heat-sensitive layer was 2: 2 by weight.
About 1 to 1:16 is preferable, and 1: 1 to 1: 3 is more preferable. When the ratio of the resin base material is less than this, it becomes difficult to form a film in which the organic low-molecular substance is held in the resin base material, and when the ratio is higher, the amount of the organic low-molecular substance is small, so that the opacity is increased. Becomes difficult.

In addition to the above components, additives such as a surfactant and a high boiling point solvent can be added to the heat-sensitive layer in order to facilitate formation of a transparent image. Specific examples of these additives are as follows. Examples of high boiling solvents: tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate, tricresyl phosphate, butyl oleate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, diphthalic phthalate -n-octyl, di-2-ethylhexyl phthalate, diisononyl phthalate, dioctyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate, dibutyl adipate, di-n-hexyl adipate, di-adipate
2-ethylhexyl, di-2-ethylhexyl azelate, dibutyl sebacate, di-2-ethylhexyl sebacate, diethylene glycol dibenzoate, triethylene glycol di-2-ethyl butyrate, methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl Phthalyl butyl glycolate, tributyl acetyl citrate.

Examples of surfactants and other additives; polyhydric alcohol higher fatty acid esters; polyhydric alcohol higher alkyl ethers; polyhydric alcohol higher fatty acid esters, higher alcohols, higher alkyl phenols, higher fatty acid higher alkyl amines, higher fatty acid amides Lower olefin oxide adducts of fats and oils or polypropylene glycol; acetylene glycol; Na, Ca, Ba or Mg salts of higher alkylbenzene sulfonic acids; higher fatty acids, aromatic carboxylic acids, higher fatty acid sulfonic acids, aromatic sulfonic acids, monoesters of sulfuric acid Or phosphoric acid mono- or di-ester Ca,
Ba or Mg salt; low sulfated oil; poly long chain alkyl acrylate; acrylic oligomer; poly long chain alkyl methacrylate; long chain alkyl methacrylate-amine-containing monomer copolymer; styrene-maleic anhydride copolymer;
Olefin to maleic anhydride copolymer.

When an image of this recording material is used as a reflection image, providing a light reflecting layer on the back of the recording layer can increase the contrast even if the thickness of the recording layer is reduced. Specific examples include vapor deposition of Al, Ni, Sn and the like (described in JP-A-64-14079).

Further, a protective layer can be provided on the heat-sensitive layer to protect the heat-sensitive layer. Materials for the protective layer (thickness 0.1 to 5 μm) laminated on the heat-sensitive layer include silicone rubber and silicone resin (described in JP-A-63-221087).
Polysiloxane graft polymers (described in Japanese Patent Application No. 62-152550) and ultraviolet curable resins or electron beam curable resins (Japanese Patent Application No. 63-3152)
No. 10600). In any case, a solvent is used at the time of coating, and it is preferable that the solvent does not easily dissolve the resin of the thermosensitive layer and the organic low-molecular substance. N-Hexane, methyl alcohol, ethyl alcohol,
Examples thereof include isopropyl alcohol, and alcohol-based solvents are particularly desirable in terms of cost.

Further, an intermediate layer can be provided between the protective layer and the heat-sensitive layer in order to protect the heat-sensitive layer from a solvent, a monomer component and the like of the protective layer-forming solution (see JP-A-1-33781). Described). As the material of the intermediate layer, in addition to those listed as the resin base material in the thermosensitive layer, the following thermosetting resin,
Thermoplastic resins can be used. That is, polyethylene,
Examples include polypropylene, polystyrene, polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate, and polyamide. The thickness of the intermediate layer is preferably about 0.1 to 2 μm.

[0025]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The parts and percentages are based on weight. Example 1 On a polyester film having a thickness of about 100 μm, 5 parts of heat-expandable microspheres (Micropearl F-30 manufactured by Matsumoto Yushi Co., Ltd.) 5 parts Carbon black 1 part PVA 10% aqueous solution 50 parts Water 45 parts The above composition was homomixed. The dispersed liquid was applied with a wire bar and dried by heating to provide a heat insulating layer of about 2 μm. 6 parts of behenic acid 4 parts of eicosane diacid 3 parts of diisodecyl phthalate 25 parts of vinyl chloride-vinyl acetate-phosphate copolymer (# 1000p, manufactured by Denki Kagaku Kogyo Co., Ltd.) 150 parts of THF and 15 parts of toluene Solution with a wire bar, heat and dry
A 7 μm thermosensitive layer was provided. Further, a solution consisting of 10 parts of a polyamide resin (manufactured by Toray Industries, Ltd .: CM8000) and 90 parts of methanol was applied by a wire bar and dried by heating to form an intermediate layer having a thickness of about 1 μm. Further, a solution consisting of 10 parts of a 75% urethane acrylate-based UV-curable resin in 10 parts of 75% butyl acetate solution (manufactured by Dainippon Ink & Chemicals, Inc .: Unidick C7-157) toluene 10 parts was applied with a wire bar, and dried by heating. After 80
The composition was cured with an ultraviolet lamp of w / cm and provided with an overcoat layer having a thickness of about 2 μm to prepare a reversible thermosensitive recording material.

Example 2 Instead of the heat-expandable microspheres, aluminosilicate micro hollow spheres (manufactured by Nippon Philite Co., Ltd.)
A reversible thermosensitive recording material was prepared in the same manner as in Example 1 except that the above-mentioned method was used.

Example 3 A synthetic paper (Yupo FPG110: Oji Yuka Synthetic Paper Co., Ltd.) was used as a support, a colored (black) support was used on the synthetic paper, and an insulating layer was provided. In the same manner as in Example 1, a reversible thermosensitive recording material was prepared.

Comparative Example A reversible thermosensitive recording material was prepared in the same manner as in Example 1 except that a heat insulating layer was provided. The reversible thermosensitive recording material prepared as described above was used to form a printed image using a thermal head of 8 dots / mm, and the image was erased using the thermal head to make it transparent. The image (cloudiness) and the erasure (transparency) were measured with a Macbeth reflection densitometer RD-514. Further, it was visually determined whether the image was uniformly erased when the image was erased. Table 1 shows the results.

[0029]

[Table 1]

[0030]

As is clear from the description of the examples, the reversible thermosensitive recording material of the present invention improves the thermal sensitivity because a heat insulating layer or a heat insulating support is provided between the support and the heat sensitive layer. In addition, the temperature of the entire recording layer can be made uniform, and a uniform transparent state can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in transparency of a reversible thermosensitive recording material according to the present invention due to heat.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kunichika Moroboshi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Toru Nogiwa 1-3-6 Nakamagome, Ota-ku, Tokyo No. Ricoh Co., Ltd. (72) Inventor Akira Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-57-109695 (JP, A) JP-A-63 JP-A-41186 (JP, A) JP-A-1-285381 (JP, A) JP-A-64-64887 (JP, A) JP-A-63-227374 (JP, A) JP-A-2-214688 (JP, A) JP-A-2-24397 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/36

Claims (2)

(57) [Claims] 1. A reversible heat-sensitive layer comprising, as a main component, a resin base material and an organic low-molecular substance dispersed in the resin base material and having a transparency reversibly changing with temperature on a support. A reversible thermosensitive recording material, wherein a heat insulating layer is provided between a support and a thermosensitive layer. 2. A reversible heat-sensitive layer comprising, as a main component, a resin base material and an organic low-molecular substance dispersed in the resin base material and having a transparency that reversibly changes depending on temperature on a support. A reversible thermosensitive recording material, wherein a heat insulating support is used as the support.