Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/28—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating
  • B41M5/287—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using thermochromic compounds or layers containing liquid crystals, microcapsules, bleachable dyes or heat- decomposable compounds, e.g. gas- liberating using microcapsules or microspheres only
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
  • B41M5/165—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components characterised by the use of microcapsules; Special solvents for incorporating the ingredients

Definitions

• the present invention relates to a color-former, and more particularly, to a color-former used as a pressure-­sensitive recording material and a temperature-indicating material under the application of microcapsules.
• the recording materials using an electron-donating colorless dye are well known as pressure-sensitive recording papers, heat-sensitive recording papers, light-sensitive recording papers, electrical heat-sensitive recording papers, temperature-indicating papers and the like, as seen in British Patent 2140,449, US Patent Nos. 4,480,052 and 4,436,920 Japanese Patent Publication No. 60-23922, Japanese Laid-open Patent Application Nos. 57-179836, 60-123556 and 60-123557, etc.
• the above-mentioned object can be achieved by using, as a main raw material of color-former, microcapsules containing an electron-donating colorless dye dispersed in a hydrophobic liquid.
• the electron-donating colorless dyes of the present invention there can be used all of the dyes previously disclosed for pressure- or heat-sensitive recording papers, for example, phthalide dyes, fluorane dyes, spiropyran dyes, diphenylmethane dyes, azine dyes, triarylmethane dyes and the like.
• phthalide dyes examples include 3,3-bis(P-­dimethylamino)-6-dimethylamino phthalide, 3-(P-dibenzylamino phenyl)-3-(1′,2′-dimethyl-3-indolyl)-7-azaphthalide, 3,3-­bis(4′dimethylamino phenyl) phthalide, 3-(4-diethylamino-2-­ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-­ 3-yl)-7-azaphthalide, 3,3-bis(1-ethyl-2-methylindol-3-yl)-4-­azaphthalide, 3,3-bis(1-ethyl-2-methylindol-3-yl)-7-­azaphthalide, 3,
• fluorane dyes examples include 3,6-dimethoxy­fluorane, 4-amino-8-diethylaminobenzo[a] fluorane, 2-amino-­8-diethylaminobenzo[a]-fluorane, 4-benzylamino-8-­diethylaminobenzo[a] fluorane, 3-diethylamino-6-methyl­fluorane, 3-diethylamino-7-aminofluorane, 3-diethylamino-7-­chlorofluorane, 3-diethylamino-5-methyl-7-t-butylfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 2-methyl-6-[N-p-­tolyl-N-ethylamino)-fluorane, 10-diethylaminobenzo[c] fluorane, spio(xanthene-9,1′-phthalan)-6-diethyla
• spiropyran dyes examples include 2,2′-spiro (benzo[f] chromene), spiro[3-methylchromene-2,2′-7′-­diethylaminochromene], spiro[3-methyl-benzo(5,6-a) chromene-­2,2′-7′-diethylaminochromene], spiro[3-methylchromene-2,2′-­7′-dibenzylaminochromene] and 3-methyl-di- ⁇ -naphtho­ spiropyran.
• diphenylmethane dyes examples include 4,4′-­bis(4,4′-tetramethyldiamino diphenylmethylamino) di­phenylmethane, bis ⁇ 4,4′-bis(dimethylaminobenzhydryl ⁇ ether, N,N′-bis[bis(4′dimethylaminophenyl) methyl]-1,6-­hexamethylene diamine, N-bis(4-dimethylaminophenyl) methyl­glycine ethyl ester and 4,4′-bis-dimethylaminobenzhydryl benzyl ether.
• Examples for azine dyes include 3,7-bis(dimethylamino) 10-benzoylphenothiazine, 10-(3′,4′,5′-trimethoxy-benzoyl)-­3,7-bis(dimethylamino) phenothiazine and 3-diethylamino-7 (N-methylanilino)-10-benzoylphenoxazine.
• triarylmethane dyes include N-butyl-3-­[bis ⁇ 4-(N-methylanilino) phenyl ⁇ methyl] carbazole, 4H, 7-­diethylamino-4,4′-bis(9′-ethyl-3′-methyl-6′-carbazolyl)-2-t-­butyloylamino-3,1-benzothiazine, 4H-7-diethylamino-4-(p-­diethylaminophenyl)-4-(9′-ethyl-3′-methyl-6′-carbazolyl)-2-­pivaloylamino-3,1-benzothiazine, 4H-6-methyl-4,4-bis(p-­dimethylaminophenyl)-2-pivaloyl-3,1-benzothiazine, 4H-7-­dibenzylamino-4,4-bis(p-dimethylaminophenyl)-2-pheny
• dyes used in the present invention include 7-chloro-1,3-dihydro-1,1-bis(p-dimethylaminophenyl)-­3-oxisobenzo [b] thieno[2,3-c] furane, spiro ⁇ chromeno[2,3-c]-­4(H)-1′-phthalan ⁇ -7-diethylamino-3-methyl-1-(p-tolyl)-3′-on, spiro[11H-benzo[b] thieno[3,2-b] chromene-11,1′-phthalan]-3-­diethylamino-7-methyl-3′-on, spiro[11H-benzo[b] thieno[3,2-­6] chromene-11,1′-phthalan] -8-chloro-3-diethylamino-6-­methyl-3′-on, lactone of 1-benzyl-2-(2-carboxy-4-dimethyl­aminophenyl)-2-
• Cationic or amphoteric surfactants easily prevent a color-formation.
• Anionic surfactants tend to form the color of a colorless dye.
• non-ionic surfactants cause neither a self color forming nor the prevention of color-forming and thus are suitable for the present invention.
• the surfactants suitable for the present invention are, e.g. sorbitane fatty acid esters, such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan sesquistearate, sorbitane monotall oil fatty acid ester, sorbitan monoisostearate, etc.; polyoxyethylene sorbit esters of fatty acids such as polyoxyethylene sorbit hexastearate, polyoxyethylene sorbit tetraoleate, etc; polyethylene glycol esters of fatty acids, such as polyoxyethylene monooleate, diethyleneglycol stearate, etc.; polyoxyethylene alkylphenyl esters such as polyoxyethylene nonylphenylether, polyoxyethylene octylphenylether, etc; derivatives of lanoline or bees wax such as polyoxyethylene sorbit bees wax, polyoxyethylene lanoline.
• sorbitane fatty acid esters such as sorbitan mono
• the following surfactants can be used for obtaining the uniform and stable dispersion of an electron-­donating colorless dye in a hydrophobic liquid, as well as the above nonionic surfactants: the so-called polymerized surfactants such as lauryl methacrylate/diethylamino acrylate copolymer polymethacrylate, polyacryl amide, vinylcarboxylate/dialkyl fumarate copolymer, alkyl­polysulfide, etc; oil-soluble polar compound of long-chain such as dialkyl dithiophosphate, etc.
• the so-called polymerized surfactants such as lauryl methacrylate/diethylamino acrylate copolymer polymethacrylate, polyacryl amide, vinylcarboxylate/dialkyl fumarate copolymer, alkyl­polysulfide, etc
• oil-soluble polar compound of long-chain such as dialkyl dithiophosphate, etc.
• the surfactants used in the present invention include further the above polymerized surfactants and the above polar compound of long chain, too.
• Each of nonionic surfactant and polar long-chain compound is used alone or together with another compound.
• the hydrophobic liquid for dispersing an electron-­donating colorless dye include natural and synthetic hydrophobic liquid and is used alone or in combination.
• Examples for the hydrophobic liquid of the present invention include natural oils such as plant oils, animal oils, etc; petroleum destillate and derivatives thereof, such as machine oil, kerosine, paraffin, naphthene oil, etc; synthetic oils such as alkylbiphenyl, alkylterphenyl, chlorinated paraffin, alkyl-naphthalene, diphenyl alkane etc; and semi synthetic oils.
• the dispersing of the dye is carried out as follows. A certain amount of the electron-donating colorless dye is introduced into a hydrophobic liquid, and is dispersed by means of a dispersing machine without heating.
• the dispersing machine there can be used, for example, ball mill, sand mill, horizontal sand mill attritor, colloid mill, etc.
• lt is suitable that the electron-donating colorless dye is dispersed in the hydrophobic liquid in a concentration of 2 - 60% by weight, preferably 10 - 50% by weight. With a concentration of less than 2% by weight, a sufficiently high color-formation is not obtained.
• the hydrophobic liquid comprises the nonionic surfactant, the polymerized surfactant and/or the polar long-chain compound in a concentration of 2 - 40% by weight, preferably 5 - 35% by weight.
• the dispersing of dye is insufficient.
• the adjustment of emulsified particle size in the capsule-forming process after the dye-dispersing is difficult and the capsul wall tend to be insufficient.
• the particle size of dye in the dye-dispersion is not otherwise limited. But with the particle size of less than 0.1 ⁇ , the stability of the emulsified particles is reduced and the coagulation occurs easily, and with the particle size of more than 5 ⁇ , color-formation is not sufficient and the smudging can be formed through dye-particles in application as a color-former for a pressure-sensitive recording paper. Accordingly, it is suitable to use a dye particle size of 1 - 5 ⁇ , preferably 0.5 - 2 ⁇ .
• the electron-donating colorless dye dispersed in a hydrophobic liquid of the present invention can be colored, with the change of temperature or in contact with an electron-accepting color-developing agent, in the same way as the dye dissolved in a solvent.
• the color-former of the present invention is coated with a binder on a base material, and in the use as a top sheet for pressure-­sensitive recording sheets, the color-former is coated with a binder and a buffer agent on a base sheet.
• the color-former of the present invention can be used in the same way as the microcapsules comprising an electron-­donating colorless dye dissolved in a solvent.
• microcapsules obtained by dispersing an electron-­donating colorless dye in a hydrophobic liquid are not easily ruptured.
• the use as the temperature-indicating material or the color-former for a pressure-sensitive recording sheet, under coating the material of the present invention on a substrate, provides a clearly dense color-­formation with little smudging and stable preservability in the storage. The reason for the above excellent features is unclear. However, it is assumed that in the conventional dye-dissolution-type color-former, dye is deposited as crystals in the lapse of time, and the capsule wall is ruptured by a slight pressure of the end or corner of the obtained crystal.
• a sheet (a top sheet) coated with microcapsules was laid on a bottom sheet (W-40-R, produced by JUJO PAPER CO., LTD.) and treated by a calender in a pressure of 50kg/cm2 to develop a color. After 6 seconds, Y-value of the color image was measured by means of Color-Difference Meter, and expressed as color-forming velocity. The smaller the value, the greater the color-forming velocity.
• a sheet coated with microcapsules was laid on the above bottom sheet and treated by a calender in a pressure of 50kg/cm2 to develop a color. After 1 hour, Y-value of the color image was measured by means of Color-Difference Meter and expressed as image density. The smaller the value, the denser the image.
• a sheet coated with microcapsules was laid on the bottom sheet and treated by a calender in a static pressure of 5kg/cm2 to develop a color. After 1 hour, Y-value of the color image was measured by means of Color-Difference Meter. The difference between the above Y-value and the Y-value of non color-developed part of the bottom sheet was expressed as smudging under static pressure. The smaller the value, the slighter the smudging.
• a sheet (top sheet) coated with microcapsules was laid on the bottom sheet. Also, 6 sheets were superposed and typewritten. The cleaness of the letter on the 6th sheet was determined by means of eyes.
• a color-former for pressure-sensitive recording sheets was obtained in the same manner as in Example 1, except that 3,6-di-(N-dimethylaminofluorane-9-spiro-3′-(6′-dimethyl­amino) phthalide (Green 118, produced by Yamamoto Kagaku (0) was used as an electron-donating colorless dye.
• Example 1-(1) 50g of 3-cyclohexylamino-6-­chlorofluorane (OR-55, produced by Yamada Kagaku Co.) as an electron-donating colorless dye and 20g of dialkyl tindithiophosphate (an oil-soluble polar long-chain compound) as a dispersing agent were added to 30g of plant oil (colza oil), and dispersed to an average particle size of 1.5 ⁇ by means of a sand mill. This dispersed liquid was added to 450g of diaryl alkane oil (Hysol SAS 296), and further dispersed. 150g of the obtained liquid were encapsulated in the same manner as in Example 1. Then, a top sheet for pressure-sensitive recording sheet was obtained and evaluated in the same way as in Example 1.
• OR-55 produced by Yamada Kagaku Co.
• dialkyl tindithiophosphate an oil-soluble polar long-chain compound
• Microcapsules and a top sheet for pressure-sensitive recording sheets were obtained and evaluated in the same manner as in Example 1, except that 4g of a liquid dispersing CVL (Crystal Violet Lactone) (Example 6) or ODB (3-dimethylamino-6-methyl-7-anilinofluorane) (Example 7) in mineral turpentine oil were further dispersed in the solvent of Example 1 or 3, and thus a dispersed liquid having a dye concentration of 2.5% was used.
• CVL Crystal Violet Lactone
• ODB 3-dimethylamino-6-methyl-7-anilinofluorane
• Examples 1 - 7 and Comparative Examples 1 and 2 were summarized in Table 1, and their evaluated results were indicated in Table 2.
• Table 2 the Examples using as a color-­former the dye-dispersion-capsules of the present invention provide practically sufficient abilities with respect to image density, color-forming velocity, smudge under static pressure and copying ability.
• Examples 2, 4 and 5 using the electron-donating colorless dyes with a poor solution-stability the dye-­dispersion capsules provide better effects in comparison with the dye-dissolution capsules giving an insufficient image density.
• Examples 6, 7 and Comparative Examples 3, 4 using the electron-donating colorless dyes with a good solution-stability the dye-dispersion-capsules provide the same effects as the dye-dissolution capsules.
• CVL as an electron-donating colorless dye were added into a solution dissolving 60g of acethyl acid phosphate (as a nonionic surfactant and hydrophobic liquid) in 110g of a isoparaffin oil (Isosol 300, made by Nisseki Chemical Co.), and were dispersed to an average particle size of 1.7 ⁇ by means of a ball mill.
• acethyl acid phosphate as a nonionic surfactant and hydrophobic liquid
• Isosol 300 isoparaffin oil
• This precondensate was added to the above o/w-emulsion, and was adjusted under mixing with agitation to a pH-value of 5.0 by using a 20% aqueous citric acid.
• the obtained liquid was heated to 60°C, held at 60°C for 2 hours, and then adjusted to a pH-value 7.5 with a 28% aqueous ammonia solution to complete the process for forming capsules.
• the color-former of the present invention provides the following superior effects, compared with the conventional color-former obtained by a dye dissolved in a solvent.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Color Printing (AREA)
• Heat Sensitive Colour Forming Recording (AREA)

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• 1989
  • 1989-03-27 JP JP1074725A patent/JPH0741738B2/ja not_active Expired - Fee Related
• 1990
  • 1990-03-22 AU AU52103/90A patent/AU630680B2/en not_active Ceased
  • 1990-03-23 EP EP19900303121 patent/EP0390432B1/de not_active Expired - Lifetime
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