JPH0145609B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive and pressure sensitive recording sheet using a photocurable capsule. More specifically, the present invention relates to a recording sheet that can be photocopied and recorded and can also be used as a light-fixing type self-coloring recording sheet.

Currently, there are a large number of methods for copying, including mechanical methods, optical methods, photographic methods, and thermal methods. However, many of these require a developing process or treatment with a fixing agent, and there are still few that are satisfactory in terms of simplicity, price, cleanliness, etc.

As an improvement on these points, the
Publication No. 20852 discloses that a substance that can be used as a dye precursor is dissolved in a solvent by irradiation with ultraviolet rays, this is encapsulated in microcapsules, which is applied onto a sheet, overlapped with an original, irradiated with ultraviolet rays, and then overlapped with an image-receiving sheet and pressurized. It is disclosed that a colored image is obtained on the surface of the image-receiving sheet corresponding to the irradiated area that has been converted into a dye precursor, and copying is completed. Although this copying method is simple, since a colored image is obtained only on the surface of the image-receiving sheet corresponding to the ultraviolet irradiation area, the originals used are limited to negative types such as photographic negatives, and cannot be used for regular handwritten manuscripts or positive types such as books. When copying a manuscript, the text becomes white and the non-text becomes colored, making it undesirable for general copying.Additionally, the microcapsules on the entire surface are destroyed by pressure, regardless of UV irradiation. , the contained substance and liquid are transferred to the entire surface of the image receiving sheet. Therefore, when irradiated with ultraviolet rays, it does not turn into a dye precursor, and a slight color may appear even on the surface of the image-receiving sheet, which should not develop color, which may adversely affect storage stability. There were some disadvantages, such as the inability to obtain colored images without it.

The inventors of the present invention have conducted research to eliminate the above-mentioned drawbacks and obtain a recording sheet that is simple, inexpensive, free from stains, and can be used for general copying. By holding on the same surface of a support the microcapsules that mainly contain the body and the microcapsules that contain the photocurable resin and the co-reactant that reacts with the reactant to form a colored substance, the desired recording sheet can be produced. I was able to get it.

Traditionally, microcapsules have been made by encapsulating liquid or solid substances, keeping them separated from other substances under normal conditions, and when necessary, applying an external impact to destroy the microcapsules and destroying the contents. The purpose is to take it out and react or mix it with other substances. For this reason, if a support coated with microcapsules is pressurized, all of the microcapsules in the pressurized area will inevitably break and the contents will inevitably leak out.

The photocurable microcapsules containing the photoreceptor photocurable resin used in the present invention are those in which the destruction of the microcapsules due to pressure is controlled by light. That is, when it is desired to take out the contents, the microcapsules are destroyed and the contents ooze out by applying an impact from the outside in the same way as with ordinary microcapsules. However, when you want to keep the inclusions intact, when you shine light on the microcapsules, the light that passes through the microcapsule wall material hardens the photocurable resin that is part of the inclusions, removing the inclusions from the liquid. Transforms into hard resin. As a result, the microcapsule becomes a rigid capsule, and even if an external impact is applied, the microcapsule will no longer be destroyed, and the contents will no longer ooze out. By using photocurable microcapsules having such characteristics, the photosensitive and pressure sensitive recording sheet used in the present invention can be obtained.

In other words, photosensitive pressure-sensitive microcapsules are mainly composed of two types of microcapsules: photocurable microcapsules containing a reactant and photocurable microcapsules containing a co-reactant that produces a colored substance upon contact with the reactant. The light-sensitive pressure-sensitive recording sheet coated with the layer and the original are placed on top of each other. At this time, if the document support is made of a material that easily transmits light, especially ultraviolet rays, the coated side of the photosensitive pressure-sensitive recording sheet and the side of the document that is not written or printed, that is, the back side, should be stacked facing each other. Expose from the original side. In addition, if the support of the original is difficult to transmit light, such as a book, the uncoated side of a photosensitive pressure-sensitive recording sheet using a transparent or nearly transparent support should face the writing or printing side of the original. The recording sheet is exposed from the recording sheet side. It is desirable to adjust the exposure time depending on the combination of the recording sheet and the original. When exposed to light, the written or printed design or character portion of the original absorbs light and the recording sheet is not exposed to light, but other areas become exposed due to the transmission or reflection of light, and the photocuring applied to these areas The contents of the mold microcapsules harden. When the exposed recording sheet is pressed with a roll or the like, the microcapsules in the areas corresponding to the designs and characters of the original are destroyed, and the reactants and co-reactants come into contact, producing colored substances.
The same designs and characters as the original are recorded.

As is already clear, when the photosensitive and pressure-sensitive recording sheet of the present invention is used, normal type originals can be used, and it can be used as any handwritten document or printed matter such as a book. In addition, since only the microcapsules in the areas corresponding to the designs and characters of the manuscript are destroyed and a colored image is formed on the recording sheet, areas other than the designs and characters will not be colored or discolored, resulting in storage stability. is extremely excellent.

The photosensitive pressure-sensitive recording sheet of the present invention can also be used as a self-coloring pressure-sensitive recording sheet that can be photofixed. What is a self-coloring pressure-sensitive recording sheet? As disclosed in U.S. Pat. No. 2,929,736, U.S. Pat. When the coated surface is written under pressure, the microcapsules in the pressurized area are destroyed, and the reactant and co-reactant come into contact, resulting in a colored image. This self-coloring pressure-sensitive recording sheet requires only one sheet of recording paper to obtain a colored image, that is, a recorded image. It consists of a so-called upper paper provided on a support, and a lower paper provided with a layer containing a co-reactant on a support. When the coated surfaces of both papers are overlapped and written under pressure, the microcapsules of the upper paper are destroyed and the co-reactant is formed on the support. Compared to pressure-sensitive sheets, which react with reactants and produce a colored recorded image on the bottom paper that corresponds to the pressurized area, it is generally widely used despite the great advantage that it does not require a combination of top paper and bottom paper. It has not been done. This is done after applying pressure and recording the color development.
This is because if you intentionally or carelessly rub or apply pen pressure, new colors will develop in areas other than the recorded image, which has the major disadvantage of staining the recorded image or changing the recorded content. .

The photosensitive pressure-sensitive recording sheet of the present invention can also fix recorded images with light, and by utilizing this, it can be used as a self-coloring recording sheet that has improved the above-mentioned drawbacks. One or more photosensitive pressure-sensitive recording sheets coated with a photosensitive pressure-sensitive layer containing two types of photocurable microcapsules containing reactants or co-reactants as main components are stacked with the coated side facing up. When pressurized with a typewriter, etc. with the ribbon removed, the microcapsules in the pressurized area are destroyed.
The reactant and co-reactant come into contact to form a colored substance.
This is obtained as a recorded image. After this, by exposing the entire coated surface to light, the unbroken microcapsules other than the recorded image are hardened from the inside and will no longer be destroyed even when pressurized.
In this way, the recorded image can be fixed. Furthermore, in addition to being used only for fixing recorded images, it is also possible to instantaneously create a so-called desensitized area using light. In other words, if the areas that do not require recording are exposed to light before using the recording sheet, the photocurable capsules in the exposed areas will harden and a colored recorded image will not be produced even if the areas are written under pressure during recording. It is also possible to prevent this from occurring.

The photocurable resin encapsulated in the photocurable microcapsules used in the present invention includes cinnamic acid residues,
Photodimerizable resins and diazonium salts with photosensitive groups such as cinnamylidene residues, α,β-unsaturated ketone residues, coumarin residues, anthracene residues, α-phenylmaleimide residues, benzophenone residues, and stilbene residues. photodegradable resin acryloyl group having a photosensitive group such as a residue, a quinone diazide residue, an azide residue, a dithiocarbamate residue, a benzoin residue,
A photopolymerizable resin having an allyl group, a vinyl group, an epoxy group, etc. can be used as desired, but a photopolymerizable resin is preferable. As for the shape, a liquid one is advantageously used. Also, known compounds that are commonly used as photopolymerization initiators for polymerizing photocurable resins may be used, such as benzoin alkyl ethers, benzophenones, Michler ketones, thioxanthones, acetophenones, etc. For example, anthraquinone, 5-nitrofluorene, etc. are used as photosensitizers that have the effect of widening the sensitive wavelength range, and stabilizers such as radical polymerization inhibitors, modifiers, and relatively low molecular weight substances are used to improve storage stability. A diluent such as an oligomer or monomer may also be included at the same time. At the same time, in order to improve the solubility of the reactants to be included, high boiling point oily solvents such as alkylnaphthalenes, alkylbiphenyls, alkylidene biphenyls,
Although esters and the like are sometimes used as solubilizing agents, it is inappropriate to use them in large amounts because they adversely affect the degree of curing.

The reactants and co-reactants used in the present invention refer to reactive compounds that react with each other to produce a colored substance. For example, a colored substance may be a colorless electron-donating compound and a colorless electron-donating compound. When the reaction occurs in combination with an accepting compound, the coreactant is the electron-accepting compound when the reactant is an electron-donating compound, and the coreactant is the electron-accepting compound when the reactant is an electron-accepting compound. The body represents an electron-donating compound. Another example of such a combination of reactive compounds is a ligand and a polyvalent metal compound. The reactive compound will be explained in more detail. As the electron donating compound, 3.3-bis(P-dimethylaminophenyl)-6-dimethylaminophthalide, 3.3
-bis(P-dimethylaminophenyl)phthalide, 3-(P-dimethylaminophenyl)-3-
Triarylmethane compounds such as (1.2-dimethylindol-3-yl)phthalide, diphenylmethane compounds such as 4.4'-bisdimethylaminobenzhydrin benzyl ether, 3-dimethylamino-7-methoxyfluorane, 3-diethylamino xanthene compounds such as -7-chlorofluorane, 3-diethylamino-7-dibenzylaminofluorane, thiazine compounds such as benzoylleucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-propyl-spirodibenzopyran, etc. Examples include spiro compounds.

Examples of electron-accepting compounds include acid clay, activated clay, inorganic acid substances such as kaolin, zeolite, and bentonite, P-cresol, P-octylphenol, P-cyclohexylphenol, P-phenylphenol, α-naphthylphenol, and Substituted phenolic compounds such as milphenol and P-chlorophenol, phenolic resin compounds such as phenol-formalin condensates, substituted phenol-formalin condensates, and metal salt-modified phenols modified with polyvalent metals such as zinc and nickel. Resin compounds, P-butylbenzoic acid, P-hydroxybenzoic acid, 2.5-dihydroxybenzoic acid, salicylic acid, 5-tert-butylsalicylic acid, 3.5-di-tert-butylsalicylic acid, 3.5-di(α-methylbenzyl)salicylic acid Aromatic carboxylic acid compounds such as and metal salts of aromatic carboxylic acid compounds made of polyvalent metals such as zinc and nickel, or aromatic carboxylic acid compounds and zinc acetate,
Examples include mixtures with polyvalent metal compounds such as zinc propionate.

The ligands include 8-quinolinol, gallic acid, gallic acid dodecyl ester, 1,10-phenanthroline, O-phenylenediamine diphenylthiourea, guanidine, hydroxynaphthoic acid,
Dipivaloylmethane, trifluoroacetylacetone, etc., and metal compounds include, but are not limited to, ferric stearate, magnesium stearate, zinc stearate, zinc N-phenyl-N-ethyldithiocarbamate, etc. It's not a thing.

The microcapsules used in the present invention can be manufactured by methods known in the art. For example, the phase separation method from an aqueous solution as shown in U.S. Patent Nos. 2800457 and 2800458, etc.,
Interfacial polymerization methods as shown in Publications No. 19574, No. 42-446, No. 771, etc., Japanese Patent Publication No. 36-9168
In-situ method by polymerization of monomers disclosed in Japanese Patent Application Laid-Open No. 51-9079, etc., British Patent No. 952807,
Examples include, but are not limited to, the melting and dispersion cooling method shown in the specification of 965074, etc., and the spray drying method shown in the specification of US Pat. No. 3,111,407, British Patent No. 930,422, etc. In addition, wall film forming materials include gelatin, gum arabic starch, sodium alginate, ethyl cellulose, carboxyethyl cellulose, polyvinyl alcohol, polyethylene, polyamide, polyester,
Polyurethane, polyethyleneimine, etc. are used, but a material that sufficiently transmits light, particularly ultraviolet light, is more preferable.

Ultraviolet light is generally used as light for curing the photocurable microcapsules used in the present invention. As the light source, sunlight, xenon lamps, low-pressure and high-pressure mercury lamps, fluorescent lamps, etc. are used. There is little deterioration in the properties of the light and pressure sensitive recording sheets due to exposure to light such as that which occurs in room lights or indirect sunlight during manufacturing and during normal handling times.

In order to hold the photosensitive pressure sensitive layer of the photosensitive pressure sensitive recording sheet of the present invention on a support, a water soluble binder and latex are generally used.

For example, gelatin, casein, carboxymethylcellulose, hydroxymethylcellulose, oxidized starch, esterified starch, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, vinyl acetate-acrylic acid copolymer, acrylonitrile-butadiene copolymer, vinylidene chloride copolymer Examples include water-soluble polymers such as polymers and latexes. These are selected from the viewpoint of film surface strength, dispersibility, etc., and used alone or in combination.

The photosensitive pressure sensitive layer of the photosensitive pressure sensitive recording sheet of the present invention further contains capsule protectants such as cellulose powder, starch particles, and plastic particles, inorganic facial sulfur such as talc, calcium carbonate, zinc oxide, and titanium oxide, and urea-formalin. Organic pigments such as resins, dispersants, antifoaming agents, etc. may be added.

Examples of the coating method include coating the entire surface of the support using an air knife coater, blade coater, gravure coater, etc., or coating a portion of the support using a flexo printing machine, gravure printing machine, etc.

The support can be arbitrarily selected from transparent, translucent, and opaque. For example, paper, various nonwoven fabrics, synthetic paper, metal foil, plastic film, etc., or a composite sheet made of a combination of these may also be used.

The present invention will be specifically explained below with reference to Examples. Note that "parts" indicate parts by weight.

Example 1 (1) Photocurable microcapsules containing reactants were prepared as follows.

100 parts of a 10% aqueous solution of ethylene-maleic anhydride copolymer, 10 parts of urea, 1 part of resorcinol, and water
200 parts were mixed to form a solution, and the pH was adjusted to 3.5 using an aqueous sodium hydroxide solution. The reactant electron-donating compound, i.e. 3-diethylamino-6-methyl-7-anilinofluorane
Epoxy acrylate photocurable resin (trade name: Lipoxin, manufactured by Showa Kobunshi Co., Ltd.) in which 7.2 parts and 0.5 parts of benzoin ethyl ether are dissolved 172.8
emulsify and disperse part of the above mixed aqueous solution until 4 to 4 oil droplets are formed.
An 8 micron oil-in-water emulsion was prepared.
Next, 25 parts of a 37% formaldehyde aqueous solution was added, the liquid temperature was maintained at 55°C, stirring was continued for 4 hours, and then the mixture was cooled to room temperature to complete the encapsulation.

(2) Photocurable microcapsules containing coreactants were prepared as follows.

3-diethylamino-6-methyl- of (1) above
Electron-accepting compounds that are co-reactants instead of 7-anilinofluorane, i.e. 3.5-di-tert
- Encapsulation was carried out in the same manner except that 9.0 parts of butylsalicylic acid and 11.5 parts of zinc octix (manufactured by Nihon Kagaku Sangyo Co., Ltd.) were used.

(3) A coating solution having the following composition was prepared and applied to paper with a basis weight of 50 g/m ² using a Mayer bar so that the coating amount was 7 g/m ² .

Reactant-encapsulating photocurable microcapsule dispersion
22 parts Co-reactant encapsulating photocurable microcapsule dispersion 44 parts 10% polyacrylamide aqueous solution 26 parts Water 50 parts The coated surface of the photosensitive pressure-sensitive recording sheet thus obtained and the manuscript were handwritten on translucent paper. After stacking the back side of the document and irradiating it with xenon light from the original side using a Resorxenofax FX-150, a light-sensitive and pressure-sensitive recording sheet is passed between rubber rolls and pressurized, and the same characters as the original are printed on the recording sheet. The copied image appeared as black. In addition, areas other than the letters remained white without any coloring.

Example 2 (1) A photocurable microcapsule dispersion containing a reactant was prepared as follows.

5% PH4.0 styrene-maleic anhydride copolymer dissolved with a small amount of sodium hydroxide
The reactant electron-donating compound, i.e. 3-(4-diethylamino-2-
Oligoester acrylate photocurable resin (trade name: Aronix, 80 parts (manufactured by Toagosei Kagaku Kogyo Co., Ltd.) were emulsified. Melamine 10 parts, 37
% formaldehyde aqueous solution and 65 parts of water were adjusted to pH 9 with sodium hydroxide and heated to 60°C.
It became transparent in 15 minutes, and a melamine-formalin initial condensate was obtained. This initial condensate was added to the emulsion, the temperature was raised to 60°C, and stirring was continued for 4 hours.
Cooled to room temperature. The solid content of the obtained microcapsule dispersion was about 45%.

(2) A microcapsule dispersion containing a co-reactant was prepared as follows.

3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide of (1) above
A microcapsule dispersion containing a co-reactant was obtained by using 8.0 parts of an electron-accepting compound as a co-reactant, namely 3.5-di-tert-butylsalicylic acid, instead of 2.4 parts. The solid content of the dispersion is approximately
It was 45%.

(3) Apply a coating solution prepared by dispersing 30 parts of zinc oxide and 5 parts of polyvinyl alcohol in 65 parts of water to a coating amount of 2.0 g/m ² on paper with a basis weight of 50 g/m ² using a Mayer bar. After that, I ran it through the super calendar once. A coating solution with the following composition was prepared on the obtained zinc oxide undercoated paper, and the coating amount was 30%.
It was coated so that the amount was 2 g/m ² .

Reactant-containing photocurable microcapsule dispersion
22 parts Co-reactant-containing photocurable microcapsule dispersion 44 parts Wheat starch 10 parts Polyvinyl alcohol 3 parts Water 172 parts IBM Typewriter Model 82C with the type ribbon removed on the photosensitive pressure-sensitive recording sheet thus obtained When printed, blue characters were obtained. When the coated surface of the recording paper bearing this colored image was irradiated with xenon light using a Resorxenofax FX-150 and printed again using the same typewriter, a blue colored image was no longer obtained.

Claims (1)

[Claims] 1 Microcapsules mainly containing a photocurable resin and a reactant, and microcapsules containing a co-reactant that reacts with the photocurable resin and the reactant to form a colored substance, on the same surface of the support. Features a photosensitive and pressure sensitive recording sheet.