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

Definitions

• the invention relates to pressure-sensitive recording sheets, in particular a color developing sheet for pressure-sensitive recording sheets, which gives a recording image with increased 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 bottom 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 because crystal violet lactone (CVL), benzoyl leucomethylene blue (BLMB), etc. were used as color formers.
• CVL crystal violet lactone
• BLMB benzoyl leucomethylene blue
• the market has asked for pressure sensitive recording sheets which provide a black image. For this purpose, 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 the combination of 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-anilino-fluoran, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (ortho, para-dimethylanilino) fluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7-anilinofluorane, etc.
• fluoran dyes when used with inorganic color developing agents such as activated clay, have the disadvantages that they give a reddish-black or greenish-black image, the resulting image undergoes hue change or fading, becoming reddish brown, and that an image with a persistent Hue cannot be obtained.
• the invention is based on the object of creating a color development sheet which, with a transfer sheet and a fluoran dye forming a black color, gives a purely black colored image with increased image density, superior light fastness and little color change. It is another object of the present invention to provide a color development sheet which, with an transfer sheet and a fluoran dye developing a blue color, gives a blue colored image with superior color development ability, durability and light fastness.
• a color development sheet which is used in combination with a transfer sheet and which consists of a support and a color development layer located on the support.
• the color development layer contains at least activated clay, a zinc compound, a thiourea compound and a bisphenol compound.
• Typical examples of dyes according to the invention which develop a black color are 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7 -anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3 -Diethylamino-7- (m-trifluoromethylanilino) fluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7- (p-methylanilino) fluoran, 3-diethyla
• Typical examples of dyes developing a blue color are triphenylmethanephthalide dyes, such as 3,3'-bis (diethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone: CVL); Phenothiazine dyes such as 3,7-bis (dimethylamino) -10-benzoyl-phenothiazine (benzoyl leucomethylene blue: BLMB); Phenoxazine dyes such as 3,7-bis (dimethylamino) -10-benzoylphenoxazine; and the like
• dyes can be used alone or in a mixture with other dyes. Furthermore, dyes which lead to the formation of a red, green or the like color can also be used in this invention.
• the dyes are dissolved in an organic solvent and by coacervation 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. They are then applied to a support to make a transfer sheet.
• thiourea compounds are thiourea, trimethylthiourea, diethylthiourea, dibutylthiourea, dilaurylthiourea, ethylene thiourea, diphenylthiourea and the like.
• thiourea compounds trimethylthiourea, diethylthiourea, diethylthiourea are preferred.
• zinc compounds leads to increased image density, superior light fastness and improved color tone.
• Typical examples of zinc compounds are zinc carbonate, zinc hydroxide, zinc oxide and the like. Of the zinc compounds mentioned above, zinc carbonate is preferred according to the invention.
• Typical examples of bisphenol compounds are 2,2'-bis (4-hydroxyphenyl) propane, 2,2'-bis (4'-hydroxyphenyl) butane, 2,2'-bis (3'-methyl-4'-hydroxyphenyl) propane, 1,1'-bis (4'-hydroxyphenyl) methane, 1,1'-bis (4'-hydroxyphenyl) ethane, 1,1'-bis (4'-hydroxyphenyl) butane, 1,1'- Bis (4'-hydroxyphenyl) heptane, 2,2'-bis (3'-phenyl-4'-hydroxyphenyl) propane, 2,2'-bis (3'-diethyl-4'-hydroxyphenyl).
• the use of the zinc compounds, thiourea compounds and bisphenol compounds leads to significant effects, namely to a pure black image with increased image density, superior light fastness and little color change when using a transfer sheet with a black color developing fluoran dye and to a colored image with superior color developability, durability and Lightfastness when using a transfer sheet with a dye developing a blue, red or green color.
• the color development layer can also contain binders and inorganic pigments.
• binders are natural or synthetic polymers such as starch, carboxymethyl cellulose, methyl cellulose, gelatin, gum arabic, polyvinyl alcohols, 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.
• novel color-developing sheet it is preferable 3 to 20 parts by weight of zinc compound, 1 to 30 parts by weight thiourea compound and 0, 1 to 5 parts by weight of bisphenol compound per 100 parts by weight of activated clay, and 10 to 40 Parts by weight of binder, based on 100 parts by weight of total solids content.
• the pH of the coating is usually about 7 to 10, but it is desirable to use a low pH to achieve more favorable fluidity and coating function.
• the color development sheet of the present invention has the advantage of using the low pH coating paint to give a superior blue image density.
• the amount of color in the color development layer is advantageously 3 to 10 g / m 2 .
• 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% aqueous solution Acetic acid solution added to adjust the pH of the solution to 4.4 while the complex coacervation was carried out. All of the above processes were carried out at a solution temperature above 50 ° C. After the solution had been cooled to 10 ° C., 3.8 parts by weight of a 37% strength aqueous formalin solution were added as a stiffening agent. After stirring, the pH of the system was adjusted to 9 with a 20% aqueous sodium hydroxide solution. In this way, a coating color was obtained from microcapsules containing a color former. The coating color was applied to a base paper having a weight of 40 g / m 2 in a coating amount of 5 g / m 2 , which resulted in a transfer sheet.
• a black image transfer sheet was prepared in the same manner except that 80 parts by weight of the oil prepared by dissolving 4% by weight of 3-diethylamino-6-methyl-7-anilinofluorane was used instead of the above Oil containing CVL and BLMB used.
• 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 / m2, thereby obtaining a color developing sheet.
• Transfer sheets according to Example 1 were used for a blue and black image.
• a transfer sheet and a color developing 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 color development is measured using a Hunter reflectometer (manufactured by Toyo Seiki Seisaku-Sho, Ltd.) using an amber filter.
• the color development rate is calculated from the reflectance I o of the sheet before the color development and the reflectance I 1 of the sheet 24 hours after the color development as follows: (Image density is expressed as the color development rate) Higher color development rate is better.
• the hue of the color development sheet on which an image was formed according to the method 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 method described in 1) is irradiated with sunlight for 2 hours, after which the light fastness is evaluated.
• the color development sheet on which an image was formed according to the method described in 1) is irradiated with sunlight for 2 hours, the change in color tone is assessed with the naked eye.
• Examples 1-6 give a blue and black image with high image density, superior image color tone and excellent light fastness and improved color change.
• the comparative experiments yield images with insufficient light fastness in blue images and with a deterioration in color tone. Furthermore, the comparative experiments yield 1-8 images with a reddish-black hue for black images, insufficient lightfastness and a large change in color. Therefore, they have no practical use.

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

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Applications Claiming Priority (2)

Publications (3)

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• 1981
  • 1981-12-24 JP JP56208149A patent/JPS58110290A/ja active Granted
• 1982
  • 1982-12-22 DE DE8282111915T patent/DE3272638D1/de not_active Expired
  • 1982-12-22 EP EP82111915A patent/EP0083075B1/fr not_active Expired
  • 1982-12-22 US US06/452,281 patent/US4480260A/en not_active Expired - Lifetime
  • 1982-12-22 AT AT82111915T patent/ATE21356T1/de not_active IP Right Cessation

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