JPH06210156A - Latent image receiving sheet - Google Patents

Abstract

PURPOSE: To obtain a latent image receiving sheet by covering a core material with a resin selected from melamine and formaldehyde, methylolmelamine, etc., and supporting the obtained microcapsules, which are not melted but broken by applying specific point source energy, on a substrate. CONSTITUTION: Microcapsules are prepared by covering the core material substantially insoluble in an aqueous vehicle with walls formed by polymerizing the resin selected from melamine and formaldehyde, methylolmelamine, etc., in situ at least 65 deg.C in a water-soluble vehicle. The formed polymerization walls of the microcapsules have less than 1% elongation and heat resistance hard to become substantially permeable even when left in the oven of 150 deg.C for 1 minute, and further are broken by imparting the point source energy of ΔT of at least 115 deg.C per 1 millisecond. The latent image receiving sheet is formed by supporting the microcapsules on the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material, and more particularly to an image receiving sheet formed of a sheet and microcapsules attached to the sheet.

[0002]

Recording materials are well known in the art and are described in many patent documents. U.S. Pat. No. 3,53
No. 9,357, No. 3,674,535, No. 3,7
46,675, 4,151,748, 4,
181, 771, No. 4,246,318, No. 4,470,057 and the like are examples thereof, and these are referred to as references of the present invention. The heat-sensitive recording material contains a basic color-forming substance and an acidic color-developing substance in a coating layer on a base material, and when heated to an appropriate temperature, the coating layer melts or softens, and both substances described above are contained. React to form colored marks. US Pat. No. 4,529,681 describes a light and heat sensitive recording material using permeable capsules in which the developer component passes through the walls of the thermoplastic capsule under the influence of heat. ing. An object of the present invention is to provide a latent image receiving sheet.

[0003]

DESCRIPTION OF THE INVENTION The present invention provides a novel non-melting microcapsule and a latent image receiving sheet using the microcapsule. The sheet provided with such microcapsules is useful for obtaining the following practical products. a) Ink transfer sheet or plate surface In this example, the microcapsules contain a dye, an ink, a pigment or a dye precursor. The latent image on this sheet is recorded by receiving a point source energy pulse having a ΔT of at least 115 ° C. per millisecond. The sheet is then pressed against the second sheet and the visible image corresponding to the latent image formed by the previously destroyed capsule is transferred to the second sheet. Sublimable dyes can also be used in this example. b) Inexpensive gravure type sheet In this example, the microcapsules contain a low boiling point or high vapor pressure solvent or gas. When this latent image receiving sheet is exposed to a point source energy pulse having a ΔT of at least 115 ° C. per millisecond, the capsules in the selected area turn into a destroyed sheet, which destroys the latent image. Form. After a suitable amount of time, the contents of the broken capsule evaporate into a cheap gravure sheet. Ink is applied to the entire sheet, and the voids formed by breaking the capsule are filled with ink.
Then, the second sheet is pressed against the latent image receiving sheet, and the image corresponding to the destroyed capsule is transferred to the second sheet. c) Confidential Message Receiving Sheet In this example, the microcapsules contain a solvent or gas with a low boiling point or a high vapor pressure, as in b) above. Upon exposure to a point source energy pulse having a ΔT of at least 115 ° C. per millisecond, the latent image receiving sheet transforms into a sheet in which the capsules in the selected area have been destroyed, and the selected area has a predetermined area. Form a latent image with a pattern. Development is accomplished by applying a fine particle toner, such as an electrostatographic toner, to the sheet, which toner preferentially adheres to the broken capsules. d) Visible image sheet In this example, the microcapsules contain either a color former or a developer. When a latent image receiving sheet is exposed to a point source energy pulse having a ΔT of at least 115 ° C. per millisecond, the capsules on the sheet turn into selected areas, ie sheets that are destroyed in a predetermined pattern, A latent image is formed with the destroyed capsules. This latent image is visualized by applying a solution or dispersion liquid of a color developer or an epoch-forming agent not contained in the contents of the capsule to the sheet.

The latent image receiving sheet of the present invention comprises a base material holding microcapsules and microcapsules which are non-melting, that is, have thermosetting resin walls.
For the wall material of the microcapsules, a resin whose elongation is less than 1% is selected. Surprisingly, the non-meltable microcapsule wall of the present invention is destroyed by applying a point source energy having a ΔT of at least 115 ° C. per millisecond. The latent image receiving sheet described above has an elongation of 1
Microcapsules with walls of thermosetting, i.e. non-melting resin, less than%, have been deposited. The thermosetting resin is preferably selected from methylated methylol melamine, melamine and formaldehyde, or methylol melamine polymerized at a temperature of at least 65 ° C. In addition, the above thermosetting resin has urea and formaldehyde (formaldehyde / urea molar ratio =
1.9 to 2.1 / 1), dimethylol urea, or methylated dimethylol urea. Some of the urea is
It can be replaced by a hydroxy-substituted phenol such as resorcinol. To reiterate, the microcapsule wall is non-melting. Table 1 shows the elongation of various resins
Shown in.

ΔT of at least 115 ° C. per millisecond
By applying a point source energy having (temperature change) to the latent image receiving sheet, the capsule is destroyed, but it is presumed that the destruction is caused by stress. The microcapsules of the present invention can contain any of the core materials that are commonly used in microencapsulation. Such core materials include solvents, various combinations of hydrophobic or hydrophilic substances, liquids (preferably hydrophobic), gases, developers or color formers, inks, dyes, toners or pigments and the like. The sheet provided with the microcapsules of the present invention has various new uses. The microcapsules are destroyed by applying point source energy having a ΔT (temperature change) of at least 115 ° C. per millisecond to this sheet. The features of the microcapsules and sheets of the present invention will be described below by taking a case where a thermal print head is used as the means for applying point source energy, but the latent image receiving sheet of the present invention is equipped in a large-scale device. Image formation is also possible with a large-scale energy input device equipped with a rapid heating block and a plurality of thermal print heads. Point source energy applying means that can be used in the present invention include a thermal print head, a laser, a concentrated hot jet, and a heating stylus (needle). On the surface of the image receiving sheet,
The ability to produce a temperature change of at least 115 ° C. per millisecond is necessary to crush the non-meltable capsules of the present invention, which crushing is believed to be associated with the development of thermal stress. Since it is undeniable that the capsule may be broken by another mechanism, it should be added that the breakage of the capsule of the present invention should not be understood to be due to only thermal stress.

Appropriate temperature change ΔT in the selected pattern
Is applied to the sheet, a latent image is recorded on the sheet by breaking the microcapsules, but if the capsule is likened to a bottle sealed with a stopper, breaking the capsule is equivalent to opening the bottle. The latent image is visualized by applying an appropriate color-developing substance to the entire surface of the sheet by a conventional application means such as sponging, spraying, and a cotton swab. When the hydrophobic substance is contained in the capsule and the hydrophobic ink or dye is applied to the surface of the sheet, the applied ink or dye is preferentially attached to the hydrophobic substance to form a visible image. The latent image receiving sheet capsule of the present invention, in contrast to the prior art,
It does not melt or become porous, but is crushed by sudden temperature changes. When the microcapsules contain a hydrophobic substance, after forming a latent image on the image receiving sheet with the thermal print head and applying hydrophobic ink on the surface, the capsules are crushed and the hydrophobic substance is exposed, The hydrophobic ink is preferentially captured, and the remaining hydrophobic ink is wiped from the sheet surface. On the contrary, when the hydrophilic substance is contained in the capsule, the hydrophilic ink is used. What is obtained in this way is an inexpensive gravure plate, that is, a transfer sheet. Also, a similar transfer sheet can be obtained by incorporating ink or dye in the capsule. If it is intended to be used as a printing plate, a flat material that is rigid in terms of durability, such as a synthetic resin, is selected as the base material. The latent image receiving sheet of the present invention can also be used as an optical recording medium for recording digitized information with a laser or a thermal print head. The latent image receiving sheet of the present invention can also be used for transferring latent information. The latent information can be provided by a thermal print head, which latent information is visualized by means as described above.

In contrast to the prior art, the capsules on the image-receiving sheet of the present invention do not melt by applying energy and do not become porous. Instead, the capsules of the invention are broken by abrupt temperature changes, such as energy pulses, i.e. abrupt changes in energy input. The energization of the image-receiving sheet with a thermal printhead or other suitable energy source that produces the appropriate temperature differential destroys the microcapsules and encodes the latent image. The fact that the capsule does not melt upon application of energy and is destroyed by a rapid temperature change suggests that this is a novel material having heat resistance. Surprisingly, the latent image receiving sheet of the present invention is
It can be left in the hot oven (150 ° C.) for about 1 minute and the capsule will not become permeable. In contrast, regular thermal paper forms an image almost immediately when placed in an oven. The isolation properties of the wall material and the lack of heat dissipation through the phase change are believed to result in high energy concentrations in the contact area between the point source and the capsule.

The elongation rate of the wall material of the microcapsules can be obtained from the physical property table of various resins. Published figures correlate well with observed phenomena and provide a convenient means for selecting resins suitable for the present invention. When a resin having an elongation rate of 1% or less is selected as a capsule wall material, a non-meltable capsule wall having a characteristic of being destroyed by thermal stress can be obtained. Table 1 shows the elongation percentages of various resins.

[Table 1] Resin name elongation (%) Acetal 60-75 Acrylic 20-50 Cellulose 5-100 Fluorcarbo 80-400 Ionomer 100-600 Polyamide 25-300 Polycarbonate 60-100 Polyethylene 5-900 Polypropylene 3-700 Polystyrene 1- 140 Vinyl 2-400 Epoxy 1-70 Phenol 1-2 Phenol formaldehyde 0.4-2 Melanmine formaldehyde 0.6-1.0 Polyester 40-300 Polyester alkyd 0.5-2 Silicone 100 Urea formaldehyde 0.5 Urethane 300- 1000 nylon 300

To determine whether the elongation of the capsule wall is suitable for the present invention, the elongation rate (%) of the polymerized bulk resin is
For example, a standard measurement method such as ASTM D638 can be used to obtain it, but a handbook showing the elongation rate (%) of various resins is available from various materials, and one example of such materials is Second edition of "Principle of Polymer Systems" by Ferdinand Rodriguez of Cornell University, published in 1970 by Hemisphere Publishing Corporation.
There are pages 532 to 537. From the elongation rate of the bulk material,
A resin that can be used in the present invention can be selected. It is believed that the capsule walls of the present invention break without melting, plasticizing with other molten materials, or increasing permeability due to phase transitions. The breakdown of the capsule is considered to be due to the large temperature gradient and the non-steady state of heat conduction. Such a state locally generates thermal stress. The strength of stress depends on the properties of the material. Weak walls are destroyed because they can withstand only small forces. Since the elongation of the resin correlates well with the brittleness of the wall, the elongation is a standard for resin selection.

The capsules according to the invention are surprisingly
It is destroyed by receiving point source energy with a temperature change (ΔT) of at least 115 ° C. per millisecond. Δ
T is calculated by the following equation. S = Eα (T−T ₀ ) S is stress, E is elastic modulus, α is linear thermal expansion coefficient, ΔT is T−T ₀ in the above equation. The stress S is 5 × 10 ³ to melamine formaldehyde polymer.
13 × 10 ³ psi (0.35 × 10 ^{3 to} 0.91 × 10 ³ kg / square cm)
The range is 5 × 10 ³ to about 9 × 10 ³ psi (0.35 × 10 ^{3 to} 0.63 × for the phenol aldehyde polymer).
It is in the range of 10 ³ kg / cm 2. In order to calculate a relatively small practical point source energy input, the stress S is (5 × 10 ³ ) psi. Elastic modulus is about (11 x 10 ⁵ ) ~
Since it is in the range of (14 × 10 ⁵ ) psi, the lower limit of E is
Adopt 11 × 10 ⁵ . The coefficient of linear thermal expansion is (4 × 10 ⁻⁵ ) ° C. Therefore, 5 × 10 ³ = (11 × 10 ⁵ ) (4 × 10 ^-5 ) (T-T
₀ ) (T−T ₀ ) = ΔT = 113.6 ° C., that is, about 115
C./millisecond The shiki value ΔT calculated by the above method is about 115 ° C.

The second method for obtaining ΔT is a method using the data obtained from the first embodiment. Example 1 is Cano
n Indicates that the temperature of the recording system surface when using a normal fax machine such as Fax 230 is higher than 170 ° C. This temperature is the temperature encountered by the paper or media. Although the temperature of the thermal print head is higher than this, the thermal stress experienced by the capsules on the surface of the paper is:
Only the temperature observed at the surface of the media is relevant. Room temperature is about 2
Since it is 5 ° C, subtracting this from the measured temperature gives 170
C-25C = 145C. Based on the amount of dye present, the ΔT at which the capsule ruptures is calculated to be at least about 115 ° C. per millisecond, but 1 per millisecond.
It is preferably 45 ° C. Since the capsules are essentially non-melting and thermosetting, there is no latent heat and virtually no phase change. In the example, the image-receiving sheet in which the capsule was broken by contact with the thermal print head was observed with a scanning electron microscope.

The core material of the capsule includes ink, pigment, toner, coloring substance, solvent, gas, liquid and pigment. The core materials are relatively individually selected. The core material may be a substantially water-soluble substance. Many of the other core materials are described in US Pat. No. 4,001,140,
This patent serves as a reference for the present invention. The core material can also be a substance dispersible in water or wrapped in a wall material, including air. Useful core materials are image-forming materials such as color-developing substances, dyes, toners and pigments. For the core material, a dye precursor that is a colorless electron-donating compound that develops a color by reacting with a developer, that is, a color-forming substance can be selected. Representative examples of such compounds include substantially colorless compounds having a lactone structure, a lactam structure, a sulfone structure, a spiropyran structure, an ester structure or an amide structure in a part of the molecular skeleton, and examples thereof include triarylmethane compounds. , Bisphenol methane compound, xanthene compound, fluorane, thiazine compound, spiropyran compound and the like. Suitable electron-donating dye precursors, i.e. color formers, for use in dye-forming systems are well known, such as phthalide compounds, leucauramine compounds and fluoran compounds. Specifically, crystal violet lactone (3,3-bis (4-dimethylaminophenyl) -6-
Dimethylaminophthalide, US Patent Reissue Patent No. 23,
024), phenyl-substituted, indole-substituted, pyrrole-substituted and carbazole-substituted phthalides (US Pat. Nos. 3,491,111, 3,491,112,
Nos. 3,491,116, 3,509,174, etc.), nitro substitution, amino substitution, amide substitution, sulfamido substitution, aminobenzylidene substitution, halo substitution, and anilino substitution fluorane (US Pat. , 624, 1
No. 07, No. 3,627,787, No. 3,641,
011; 3,642,828; 3,68
1,390, etc.), spirodipyran (see US Pat. No. 3,853.8869), pyridine compounds and pyrazine compounds (see US Pat. Nos. 3,775,424 and 3,971,808), etc. It can be illustrated. Other suitable color-forming substances are 3-diethylamino-6-methyl-7-anilino-fluorane (U.S. Pat. No. 3,681,390) and 3-dibutylamino-6-methyl-7-anilinofluorane. Also known as 2-anilino-3-methyl-6-dibutylaminofluorane (US Pat. No. 4,510,513), 3-dibutylamino-7- (2-chloroanilino) fluorane, 3-
(N-ethyl-N-tetrahydrofurfurylamino)-
6-methyl-7,3,5'6-tris (dimethylamino) spiro [9H-fluoren-9'1 (3'H) -isobenzofuran] -3'-one, 7- (1-ethyl-2)
-Methylindol-3-yl) -7- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyrid-5-one (US Pat. No. 4,24)
6,318), 3-diethylamino-7- (2-chloroanilino) fluorane (US Pat. No. 3,920,51).
No. 0), 3- (N-methylcyclohexylamino) -6
-Methyl-7-anilinofluorane (US Pat.
59,571), 7- (1-octyl-2-methylindol-3-yl) -7- (4-diethylamino-2-).
Ethoxyphenyl) -5,7-dihydrofuro [3,4-
b] Pyridin-5-one, 3-diethylamino-7,8
-Benzofluorane, 3,3-bis (1-ethyl-2-
Methylindol-3-yl) phthalide, 3-diethylamino-7-anilinofluorane, 3-diethylamino-
7-benzylaminofluorane, 3'-phenyl-7-
Dibenzylamino-2,2'-spiro-di- [2H-1
-Benzopyran], etc., but all the above-mentioned specific examples do not limit the present invention.

The solvent shown below can also be optionally contained in the microcapsules. 1. A dialkyl phthalate having an alkyl group with 4 to 13 carbon atoms (for example, dibutyl phthalate, dioctyl phthalate, dinonyl phthalate, ditridecyl phthalate, etc.), 2.2,2,2-trimethyl-1,3-pentanediol diisobutyrate Rate (US Pat. No. 4,027,065
No.) 3. Ethyldiphenylmethane (US Pat. No. 3,996,
No. 405) 4. Alkyl biphenyls such as monoisopropyl biphenyl (US Pat. No. 3,627,581) 5. 5. C10-C14 alkylbenzenes such as dodecylbenzene, 6. 6. Diaryl ethers such as diphenyl ether, dibenzyl ether, phenylbenzyl ether, di (aralkyl) ethers, aryl aralkyl ethers, 7. Liquid higher dialkyl ether (having at least 8 carbon atoms) 8. Liquid higher alkyl ketones (having at least 9 carbon atoms) 9. Alkyl or aralkyl benzoates (eg benzyl benzoate) 10. Alkylated naphthalene 11. Partially hydrogenated terphenyl

When a solvent is used, the solvent is selected so that it can dissolve the dye mixture. When the capsules contain a color-forming substance, the latent image on the image-receiving sheet is visualized with a dispersion or solution, preferably of a variety of common acidic developer substances. Alternatively, the acidic developer material can be pre-disposed in a relationship substantially adjacent to the color developing material. Position the developer in the capsule and after breaking the capsule,
The developer may be applied, or conversely the developer may be located within the capsule. Useful acidic developers include clays, treated clays (US Pat. Nos. 3,622,364 and 3,753,761), aromatic carboxylic acids such as salicylic acid, their derivatives and their metal salts (US Pat. Patent No. 4,022,936), phenolic developers (US Pat. Nos. 3,244,550 and 4,573,063).
Acidic polymers such as phenol formaldehyde polymers (US Pat. Nos. 3,455,721 and 3,
672,935), metal-modified phenolic resins (US Pat. Nos. 3,732,120, 3,737,410,
No. 4,165,102, No. 4,165,103, No. 4,166,644, No. 4,188,456).

The method of forming microcapsules is well known as described in US Pat. No. 2,730,456. Another effective method of making microcapsules is
U.S. Pat. Nos. 4,001,140, 4,081,376 and 4,089,802, which describe the reaction of urea with formaldehyde, U.S. Pat. , 100, 103
And the method of British Patent No. 2,062,750 for producing a capsule wall obtained by polymerizing melamine and formaldehyde in the presence of styrenesulfonic acid. More preferred methods for the present invention are U.S. Pat. Nos. 4,001,140, 4,089,802, 4,100,103, 4,105,823 or 4,552. , 811,
A method of forming microcapsules from a urea-formaldehyde resin and / or a melamine-formaldehyde resin. Among them, the method of US Pat. No. 4,552,811 is preferable. Each of the above US patents is incorporated herein by reference.

The recording material is generally provided with a sheet-shaped support. In the present invention, a sheet is a generic term for a support, which includes a web, a roll, a ribbon, a tape, a belt,
Includes films, cards, etc. Sheet refers to an article that has two large surface dimensions and a relatively small thickness dimension. The support may be opaque, colorless and transparent, or translucent, and may or may not itself be colored. The support may be a fibrous material such as paper or a filamentary synthetic material, or a cellophane, or a film such as a molded or extruded synthetic resin sheet. Binders may also be used to adhere the capsules to the support and include polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, methyl hydroxypropyl cellulose, starch, modified starch, gelatin and the like. Latexes such as polyacrylates, styrene-butadiene, rubber latex, polyvinyl acetate and polystyrene are also useful.

The following examples specifically illustrate the present invention, but do not limit the present invention.
In the examples, all parts and ratios are by weight unless otherwise specified. Example 1 (Confirmation of Surface Temperature of Medium Using Fax Machine) The color former dispersion was applied to thin translucent paper to obtain a coating film.
A section of this coating was taped to bond paper and used as a copy sheet for the fax machine Canon Fax-203. Melting of the coating is confirmed by the appearance of clear traces (without a clear shape) on the opaque substrate. By this method, it was confirmed that the temperature of the medium surface of Canon Fax-203 was at least 170 ° C. Coloring agent melting temperature Whether or not it melts in the device Dibutyl N102 Approx. 170 ° C Melting Yes PSD-150 About 200 ° C No melting Green 118 About 230 ° C No melting Note) Melting temperature is Kofler Hot Bar
Measured with the above crushed material

Example 2 Preparation of microcapsules Composition of internal phase 20 g N102 180 g Trimethylolpropane triacrylate (TMPTA) monomer 2 g 2-Isopropylthioxanthone (photoinitiator) 2 g Ethyl-4-dimethylaminobenzoate (photoinitiator) 24 g 2,2-Dimethoxy-2-phenylacetophenone (photoinitiator) The first two components were mixed and melted by heating, and then the photoinitiator was dissolved. Composition of external phase 25 g Colloid 351 (solid content: about 25%) Acrylic polymer manufactured by Lone Poulin, (butyl acrylate) 198 g Water 20% NaOH to adjust pH to 5.0. Emulsification 170 g of the above external phase was placed in a mixer, and the above internal phase solution was added while gently stirring. Then, it is measured by a Microtrac particle size analyzer manufactured by Reed and Northlap Instruments to obtain a desired dropping particle size (for example, 50
The stirring speed was increased until the volume% was approximately 4.0 μ). Encapsulation The following ingredients were mixed. 25 g Colloid 351 (solid content about 25%) 42 g Water 20% NaOH to adjust the pH to 4.8 30 g Cymel 385 (solid content about 80%) 70 g of this mixture was added to the above emulsion and this in a water bath Transferred to container. 6 emulsions with stirring
It was heated to 5 ° C. and kept in this state for several hours until encapsulation occurred. Note: Cymel is a trademark of American Cyanamide Company, and Cymel 385 is an etherified methylol melamine oligomer. Coating The following two components were mixed in equal parts by weight. 1. Capsule dispersion obtained as described above 1. 10% aqueous solution of Airvol 103 Note) Airvol is a trademark of polyvinyl alcohol manufactured by Air Products and Chemicals. This mixed solution is mixed with, for example, a gap of 0.001 inch (about 0.2 inch).
A gap applicator with a constant gap set to 5 mm) was used to coat and dry the paper or other desired support. This is a commercial facsimile machine thermal printer capable of forming a latent image. This latent image can be visualized by coating or contacting with a suitable developer for the color former N102. A typical example of the color developer is 20% prepared by dissolving Duretz # 27691 (p-phenylphenolformaldehyde resin) in xylene.
It is a solution. This resin can be applied in the form of an aqueous dispersion or emulsion, and heating after application promotes black color development. If necessary, the obtained copy image can be exposed to ultraviolet rays to polymerize the respective components and be fixed so as to be insensitive to heat and / or pressure. Exposure to a 15 watt GED bulb for 5 seconds is sufficient to effect this fusing. The image after fixing has durability against rubbing. Since the coating layer before fixing is reactive, the coating layer may be damaged during handling. However, the damage described above can be reduced by applying an overcoat that does not adversely affect the thermal image formation and the subsequent fixing. A typical overcoat is #
Applying a 10% aqueous solution of air balls 540 using a three wire wound rod. The photoinitiator can be excluded from the internal phase of the capsule. Further, the color former can be optionally contained or excluded.

Example 3 (dry development) a. Two sheets were prepared. -The microcapsules of Example 2 were applied to one sheet. The developer composition was applied to the other sheet. b. A latent image was formed on the capsule-containing sheet with a thermal print head. c. The faces of the latent image sheet and the developer sheet are matched. The developer sheet is a sheet coated with a phenolic resin dispersion liquid, and the resin dispersion liquid is Duretz 32421.
(Phenolic resin dispersion, solid content about 50%), benzoic acid, 2-hydroxy polymer, formaldehyde, nonylphenol, zinc oxide. Both sheets of the same face were fed together between two rolls heated to 110 ° C. d. When the support of the developer sheet was peeled off, a fully developed image appeared on the latent image sheet.

Example 4 Composition of internal phase 160 g TMPTA 40 g Duretz # 27691 (p-phenylphenolformaldehyde resin) 12 g 2,2-dimethoxy-2-phenylacetophenone (photoinitiator) The above resin was added to TMPTA while heating. Dissolve, then add photoinitiator to dissolve. This internal phase was encapsulated in the same manner as in Example 2, the obtained capsule dispersion was applied to a support, and a top coat was applied. An image was formed on the medium thus obtained by a commercial facsimile. The image was visualized with a commercial toner such as Minolta MT Toner II. The black toner particles selectively attached to the image-wise destroyed capsules. The toner on the substrate was lightly brushed to remove it, and then heat fusion was performed in an oven or in a heated drum.

Example 5 An image was formed using FAX as in Example 4, the second color was added and the toner application process was repeated. As a result, a multicolor image could be obtained. Example 6 (Image transfer to flat paper) a. The toner-developed plastic sheets as in Examples 3 or 4 were aligned with bond paper and fed between two rolls heated to 90 ° C. b. The plastic sheet was removed. c. A transfer image was obtained on a flat paper. Example 7 (image formation with toner) a. Microcapsules of melamineformaldehyde containing only the solvent sec-butylbiphenol (SureSol 290) were prepared according to the invention. b. An image sheet was prepared by applying the above microcapsules on a plastic sheet and applying a PVA overcoat. c. A latent image was obtained using Canon Fax-203 in copy mode. d. A portion of the sample was placed in a container containing commercial toner (electrostatographic toner). e. The container was sealed and rocked to deposit toner on the sample surface. f. The brush was used to remove excess toner from the sample, resulting in a red image on a white substrate.

Example 8 (Image formation by thermal transfer ribbon) a. A sheet with capsules containing no dye or developer was used. b. A latent image was recorded on this sheet using Canon Fax-203. c. The sheet on which the latent image was formed by selectively breaking the capsules was brought into contact with the coated surface of the thermal transfer ribbon, and this was passed through a heated roll. d. The plastic of the thermal transfer ribbon was removed and a colored image was obtained on the sheet. Example 9 (transfer sheet) a. The latent image was recorded on a sheet coated with microcapsules containing only solvent using Canon Fax-203. b. The blue ink was evenly distributed on the surface of the sheet. c. The excess ink was removed by pressing the ink-coated sheet against the paper on which the clay was smoothly applied. d. The ink side of this sheet was placed on a flat paper surface and passed between steel pressure rolls (applied pressure =
170 lbs / inch). A blue print with good contrast was obtained on the paper. e. Further, a commercial printing press ink was used in place of the above blue ink. When excess ink was removed with a blade and transferred to paper, a clear black print was obtained on a white background. Example 10 (transfer sheet) Composition of internal phase 180 g TMPTA monomer 20 g 1,3,3-trimethylindolino-6'-chloro-8'-methoxybenzopyrirospirane 12 g 2,2-dimethoxy-2-phenylacetophenone (Photoinitiator) The above components were mixed and heated and melted. This internal phase was encapsulated by the method of Example 1 and the resulting capsule dispersion was applied onto a suitable support using a # 12 wire-wound rod.
After the coating layer was dried, a 10% aqueous solution of air ball 540 was top-coated on the coating layer using a # 3 wire-wound rod.
The sheet was passed through a commercial facsimile machine to print the master image. When this master image was brought into contact with the developer sheet and heated, spirane sublimated from the broken capsule forming the latent image, so that a copy image could be obtained. The master image can be used repeatedly to obtain one or more duplicate images. Reproduction images can also be formed on commercially available carbonless CF sheets, such as those containing p-phenylphenol formaldehyde resin.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location B41M 5/26 G03F 7/004 514 7/105 504 8305-2H B41M 5/26 P (72) Invention Rowell Schleicher Wisconsin, USA 54911, Appleton, Foxpoint Drive 86 (72) Inventor Robert W. Brown, USA Wisconsin 54911, Appleton, Estherbrook Court 91 (72) Inventor Lucy Feldman USA Wedgewood Drive 4012, Appleton, Wisconsin 54915

Claims (27)

[Claims] 1. A polymer wall produced by in situ polymerization of a resin selected from melamine and formaldehyde, methylol melamine or methylated methylol melamine in an aqueous vehicle at a temperature of at least 65 ° C. A microcapsule produced by a method of encapsulating a substantially insoluble capsule core material in an aqueous vehicle, wherein the polymer wall of the microcapsule has an elongation not exceeding 1%, and is left in an oven at 150 ° C for 1 minute. Even if
Non-melting microcapsules that have heat resistance that is not substantially transparent and that are destroyed by applying a point source energy of ΔT of at least 115 ° C. per millisecond. 2. ΔT is at least 145 ° C. per millisecond.
The microcapsule according to claim 1, which is 3. The microcapsule according to claim 1, wherein the resin is a melamine resin. 4. The microcapsule according to claim 1, wherein the resin is methylated methylolmelamine. 5. The microcapsule according to claim 1, wherein the polymerization of the resin is carried out at about 75 ° C. 6. The microcapsule according to claim 1, wherein the core material is a hydrophobic substance. 7. In-situ a resin selected from formaldehyde, dimethylol urea or methylated dimethylol urea in the aqueous vehicle having a formaldehyde / urea molar ratio of 1.9 / 1 to 2.1 / 1. (In situ) A microcapsule produced by a method of encapsulating a capsule core material that is substantially insoluble in an aqueous vehicle in a polymerization wall formed by polymerization, and the polymerization wall of the microcapsule exceeds 1%. 1 with no elongation, 150 ° C oven
It has heat resistance that does not become substantially permeable even when left standing for at least 1 minute, and at least 115 ° C per millisecond.
Non-melting microcapsules that are destroyed by applying point source energy of ΔT. 8. ΔT is at least 145 ° C. per millisecond
The microcapsule according to claim 7, which is 9. The microcapsule according to claim 7, wherein the resin is dimethylol urea. 10. The microcapsule according to claim 7, wherein the resin is methylated dimethylol urea. 11. The microcapsule according to claim 7, wherein the resin further contains resorcinol. 12. The microcapsule according to claim 7, wherein the molar ratio of formaldehyde to urea is 2: 1. 13. The microcapsule according to claim 7, wherein the core material is a hydrophobic substance. 14. A resin selected from melamine and formaldehyde, methylol melamine or methylated methylol melamine in an aqueous vehicle at least 65 ° C.
It is produced by the method of encapsulating a capsule core material that is substantially insoluble in an aqueous vehicle with a polymerization wall produced by in situ polymerization at a temperature of 1%.
Has an elongation not exceeding 100 ° C., has a heat resistance that does not become substantially permeable even when left in an oven at 150 ° C. for 1 minute, and has a ΔT of at least 115 ° C. per millisecond.
A latent image receiving sheet comprising non-melting microcapsules, which are destroyed by applying point source energy, on a substrate. 15. ΔT is at least 145 per millisecond.
The image receiving sheet according to claim 14, which has a temperature of ° C. 16. The image-receiving sheet according to claim 14, wherein the resin is a melamine resin. 17. The image-receiving sheet according to claim 14, wherein the resin is methylated methylolmelamine. 18. The image-receiving sheet according to claim 14, wherein the polymerization of the resin is carried out at about 75 ° C. 19. The image-receiving sheet according to claim 14, wherein the core material is a hydrophobic substance. 20. The image-receiving sheet according to claim 14, wherein the core material is selected from the group consisting of ink, dye, toner, coloring substance, solvent, gas, hydrophobic liquid and pigment. 21. In situ, a resin selected from formaldehyde, dimethylolurea or methylated dimethylolurea and urea having a formaldehyde / urea molar ratio of 1.9 / 1 to 2.1 / 1 in an aqueous vehicle. (in situ)
A microcapsule produced by a method of encapsulating a capsule core material, which is substantially insoluble in an aqueous vehicle, in a polymerization wall formed by polymerization, wherein the polymerization wall of the microcapsule has an elongation not exceeding 1%. However, even if it is placed in an oven at 150 ° C for 1 minute, it has heat resistance that is not substantially permeable, and at least 115 per millisecond.
A latent image receiving sheet in which non-melting microcapsules, which are destroyed by applying point source energy of ΔT at ℃, are held on a substrate. 22. ΔT is at least 145 per millisecond.
The image-receiving sheet according to claim 21, which has a temperature of ° C. 23. The image-receiving sheet according to claim 21, wherein the resin is methylated dimethylol urea. 24. The image-receiving sheet according to claim 21, wherein the resin further contains resorcinol. 25. The image receiving sheet according to claim 21, wherein the molar ratio of formaldehyde to urea is 2: 1. 26. The image-receiving sheet according to claim 21, wherein the core material is a hydrophobic substance. 27. The image-receiving sheet according to claim 21, wherein the core material is selected from the group consisting of ink, dye, toner, coloring substance, solvent, gas, hydrophobic liquid and pigment.