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
  • B41M5/124—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
  • B41M5/132—Chemical colour-forming components; Additives or binders therefor
  • B41M5/155—Colour-developing components, e.g. acidic compounds; Additives or binders therefor; Layers containing such colour-developing components, additives or binders
• • 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
  • B41M5/132—Chemical colour-forming components; Additives or binders therefor
  • B41M5/136—Organic colour formers, e.g. leuco dyes
  • B41M5/145—Organic colour formers, e.g. leuco dyes with a lactone or lactam ring
  • B41M5/1455—Organic colour formers, e.g. leuco dyes with a lactone or lactam ring characterised by fluoran compounds

Definitions

• the invention relates to pressure-sensitive recording sheets, in particular a color-developing sheet for 'pressure-sensitive recording sheets which gives a recorded image with high image density and superior light fastness.
• the pressure sensitive recording sheets consist of an upper sheet (CB-coated underside) and a lower sheet (CF-coated upper side).
• the underside of the upper sheet is coated with microcapsules which contain an electron-donating, colorless or slightly colored chromogenic dye which is dissolved in an organic solvent (capsule oil).
• the surface of the lower sheet is coated with a color development layer containing an electron-accepting color development agent.
• the surface of the middle sheet (CFB-coated top and bottom) is coated with a layer comprising a color developing agent, and the underside - of the middle sheet is coated with microcapsules containing the chromogenic dye. If you put one or more CFB sheets between the CB and CF sheets, you can get one or more copies.
• the activated clay is produced by treating the acidic clay or the like with a mineral acid for the purpose of dissolving aluminum, iron and other basic components, thereby increasing its specific surface area.
• a specific surface area of over 200 m 2 / g gives a preferred color development effect.
• Activated clay has the advantage that it is much cheaper than known organic color developing agents.
• the color for the image of the pressure-sensitive recording sheets was only blue, since crystal violet lactone (CVL), benzoyl leuco methylene blue (BLMB), etc. were used as color formers.
• CVL crystal violet lactone
• BLMB benzoyl leuco methylene blue
• the market has asked for pressure sensitive recording sheets which provide a black image.
• mixtures of two or more different dyes that have multiple shades have been proposed, see Japanese Patent Publications 4698/1970, 4614/1971, etc.
• the black color developing dye can be combined by combining blue and yellow orange dye, blue and yellow and yellow orange and red dye, three basic dyes such as blue-green-red dyes, etc., or two dyes form counter-colors with each other.
• fluoran dyes which themselves form a black color have been developed.
• dyes of this type are 3-diethylamino-6-methyl-7-anilinofluoran, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (artho , para-dimethylanilino) -fluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7-anilinofluorane, etc.
• fluoran dyes have on when used with inorganic color developing agents, such as activated T, the disadvantages that they result in a reddish-schwärzes or greenish-black image, the image of a color change or fading obtained subject, being red-brown, and that an image with a permanent shade cannot be obtained.
• the invention is based on the object of creating pressure-sensitive recording sheets in which a pure black colored image with increased image density, superior light fastness and little change in color tone can be achieved with a color development sheet, a transfer sheet and a black-forming fluoran dye.
• dyes are dissolved in an organic solvent and by preservation processes (see, for example, US Pat. No. 2,800,457), interfacial polymerization processes (see, for example, Japanese patent publication 19578/1963), "in-situ” polymerization processes (see, for example, Japanese patent publication) 45133/1974) and the like, encapsulated. They are then applied to a support to make a transfer sheet.
• the color development sheet according to the invention which is used in combination with the above transfer sheet, consists of a support and a color development layer lying on the support, which contains activated clay, zinc carbonate and a thiourea compound.
• the use of zinc carbonate and thiourea compound in addition to activated clay in the color development layer leads, in conjunction with the fluoran dyes used according to the invention, to a purely black-colored image with an increased image density, and an improved light fastness and less color change.
• the addition of thiourea compound leads to a purely black color shade, an improved light fastness and a lower color shade change.
• thiourea compounds according to the invention are thiourea, trimethylthiourea, diethylthiourea, dibutylthiourea, dilaurylthiourea, ethylene thiourea, diphenylthiourea and the like.
• thiourea compounds trimethylthiourea, diethylthiotiarea, dibutylthiourea and diphenylthiourea are preferred according to the invention.
• the addition of zinc carbonate leads to increased image density, superior light fastness and improved color tone.
• the zinc carbonate of the present invention includes zinc carbonate and basic zinc carbonate, which are available on the market.
• the addition of zinc oxide results in a lower image density and inferior light fastness and the image becomes reddish when exposed to sunlight or ultraviolet rays.
• binders in the color development layer are natural or synthetic polymers, such as starch, carboxymethelcellulose, methyl cellulose, gelatin, gum arabic, polyvinyl alcohol, casein, Styrene-butadiene copolymer latices and the like.
• inorganic pigments are natural or synthetic inorganic pigments such as clay, talc, kaolin, calcium carbonate, basic magnesium carbonate, barium sulfate, barium carbonate, aluminum hydroxide, zinc white and the like.
• the color development sheet according to the invention it is advantageous to use 3 to 20 parts by weight of zinc carbonate, 1 to 30 parts by weight of thiourea compound per 100 parts by weight of the activated clay and 10 to 40 parts by weight of binder, based on 100 parts by weight. Parts total solids content to use.
• a solution of 20 parts by weight of gum arabic in 160 parts by weight of water was added to the dispersion, and 550 parts by weight of water were added with further stirring. Then, a 10% acetic acid aqueous solution was added to adjust the pH of the solution to 4.4 while the complex preservation was carried out. All of the above processes were carried out at a solution temperature above 50 ° C.
• the coating color obtained was applied to a base paper having a weight of 40 g / m 2 in a coating amount of 7 g / m 2 , whereby a color developing sheet was obtained.
• Transfer Sheet The transfer sheet of Example 1 was used as such.
• Color development sheets were prepared in the same manner as in Example 1 using various thiourea compounds and zinc carbonate and varying the amounts.
• the transfer sheet of Example 1 was used.
• the color development sheets were prepared in the same manner as in Example 1, with the color development sheets containing the components described in Table I. Thiourea was immediately dissolved in the activated clay dispersion because thiourea is readily soluble in water.
• a transfer sheet and a color development sheet are placed on top of each other so that the coated surfaces of the sheets touch each other.
• the stacked sheets are written on with a typewriter so that a color forms.
• the reflectance of the sheet 24 hours after the color development is measured using a Hunter reflectometer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) using an amber filter.
• the F arbillessrate is calculated from the reflectivity Io of the sheet before the color development and the reflectance I, the sheet 24 hours after the color development is calculated as follows:
• Image density is expressed as the color development rate. Higher color development rate is better.
• the hue of the color developing sheet on which an image has been formed according to the procedure described in (1) is evaluated with the naked eye 24 hours after the color development.
• the color developing sheet on which an image was formed according to the procedure described in (1) is irradiated with sunlight for 2 hours, after which the light fastness is evaluated.
• the color developing sheet on which an image has been formed according to the method described in (1) is exposed to sunlight for 2 hours, and the change in hue is assessed with the naked eye.
• Comparative experiments 1-5 result in high image density, but lead to reddish-black coloring, result in inferior light fastness and / or change in color.
• the comparative experiments 6 - 11 give pure black F arbical or a slightly reddish black, however, lead to lower image density.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Color Printing (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

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ID=16356971

Family Applications (1)

Country Status (5)

Cited By (6)

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Citations (4)

Family Cites Families (2)

• 1981
  • 1981-12-08 JP JP56196384A patent/JPS5898281A/ja active Granted
• 1982
  • 1982-11-19 US US06/442,966 patent/US4473832A/en not_active Expired - Lifetime
  • 1982-12-06 DE DE8282111278T patent/DE3263698D1/de not_active Expired
  • 1982-12-06 AT AT82111278T patent/ATE13159T1/de not_active IP Right Cessation
  • 1982-12-06 EP EP82111278A patent/EP0081228B1/fr not_active Expired

Patent Citations (4)

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