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
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/333—Colour developing components therefor, e.g. acidic compounds
  • B41M5/3333—Non-macromolecular compounds
  • B41M5/3335—Compounds containing phenolic or carboxylic acid groups or metal salts thereof
  • B41M5/3336—Sulfur compounds, e.g. sulfones, sulfides, sulfonamides

Definitions

• the present invention relates to novel color developers for use in carbonless copy papers (CCP) and thermal imaging papers (TP) which will produce a stable intense mark when placed in contact with colorless dye precursors.
• CCP carbonless copy papers
• TP thermal imaging papers
• the present invention also relates to record material sheets bearing a coating which contains such novel color developers.
• Pressure-sensitive or heat-sensitive recording papers rely on two components to form color.
• One component is a colorless or slightly colored dyestuff or color precursor.
• the other component is an acidic material or color developer which is capable of forming a color by reaction with the dyestuff or color precursor. Marking of the recording papers is effected by pressure or heat which transfers one reactant to the other.
• Pressure-sensitive recording material consists, for example, of at least one pair of sheets which contain at least one dyestuff or color precursor, dissolved in an organic solvent, and a color developer.
• the dyestuff or color precursor effects a colored marking at those points where it comes into contact with the color developer.
• the color precursors contained in the pressure-sensitive recording material are usually separated from the developer. This can advantageously be accomplished by incorporating the color precursors in foam like, sponge-like, or honeycomb-like structures.
• the color formers are enclosed in microcapsules which usually can be ruptured by pressure.
• a layer of pressure-rupturable microcapsules containing a solution of colorless or slightly colored dyestuff or color precursor is normally coated on the backside of the front sheet of paper of a carbonless copy paper set.
• This coated backside is known as the CB coating.
• the CB coating In order to develop an image or copy, the CB coating must be mated with a paper containing a coating of suitable color developer on its front. This coated front color developer coating is called the CF coating.
• Marking of the pressure-sensitive recording papers is effecting by rupturing the capsules in the CB coating by means of pressure to cause the dyestuff precursor solution to be exuded onto the front of the mated sheet below it.
• the colorless or slightly colored dyestuff, or dyestuff precursor then reacts with the color developer in the areas at which the pressure was applied, thereby affecting the colored marking.
• Such mechanism or the producing technique of pressure-sensitive recording papers is well known.
• thermoreactive recording material usually contains at least one carrier, one color precursor, one solid developer and, optionally, also a binder.
• the thermoreactive recording systems comprise, for example, heat-sensitive recording and copying materials and papers. These systems are used, for example, for recording information, e.g., in electronic computers, teleprinters or telewriters, or in recording and measuring instruments.
• the image (mark) formation can also be effected manually with a heated pen.
• Laser beams can also be used to produce heat-induced marks.
• the thermoreactive recording material can be so composed that the color presursor is dispersed or dissolved in one binder layer and the developer is dissolved or dispersed in the binder in a second layer. Another possibility consists in dispersing both the color precursor and the developer in one layer. By means of heat, the binder is softened at specific areas and the color precursor comes into contact with the developer at those points where heat is applied and the desired color develops at once.
• Color precursors are well known to those experienced in the field and any such color former may be used in conjunction with the present invention, e.g., those belonging to the classes of the phthalides, fluoranes, spiropyranes, azomethines, triarylmethane-leuco dyes, of the substituted phenoxazines or phenothiazines, and of the chromeno or chromane color formers.
• Such suitable color precursors are: crystal violet lactone, 3,3-(bisamino-phenyl)-phthalides, 3,3-(bisubstituted indolyl)-phthalides, 3-(aminophenyl)-3-indolyl­phthalides, 6-diaalkylamino-2-n-octylaminofluoranes, 6-dialkylamino-­2-arylaminofluoranes, 6-dialkylamino-3-methyl-2-arylaminofluoranes, 6-dialkylamino-2- or 3-lower alkylfluoranes, 6-dialkylamino-2-­dibenzylaminofluoranes, 6-dialkylamino-2-dibenzylaminofluoranes, 6-diethylamino-1,3-dimethylfluoranes, the lactonexanthenes, the leucoauramines, the 2-(omega substituted vinylene)-3,3-­disubstituted
• a further object of the present invention to provide such a color developer with excellent color developing properties.
• novel color developers of the present invention which are, in part, N-monosubstituted sulfonamides which contain at least one electron-withdrawing group.
• the simple sulfonamides and n-monoalkyl sulfonamides (RSO2NH2 and RSO2NHR' respectively) have acidities that are too weak for these materials to be very useful as primary color developers. They are useful as film modifiers and/or secondary color developers.
• an electron-withdrawing group not more than five (5) atoms from the NH group on the sulfonamide increases its acidity (via the inductive effect), and makes the sulfonamides suitable for use as primary color developers.
• the pK a (-log K a , where K a is the acid dissociation constant) of the sulfonylamide (-SO2-NH-) group should be in the range of 9.5 to 2.5, and preferably in the range of 8 to 4.
• Suitable electron-withdrawing groups are those substituents which possess positive Hammett or Taft constants.
• the novel color developers can also be N-monosubstituted, N'-mono or di-substituted sulfamides [R'''(R o ")-N-SO2NHR o ']. Again for the reasons stated above, an electron-withdrawing group must be no more than 5 atoms from the NH group.
• the maximum color developing potential is realized when these N-monosubstituted sulfonamides or N,N'-substituted sulfamides are used in conjunction with some source of metal or metal compound.
• the sulfonamines or sulfamides may be
• the latter will take the form of organic acid salt formation by reacting either an extra group or a COOX group in the sulfonamide or sulfamide with a basic metal oxide or carbonate.
• the salt may also be formed by reaction of alkali salt of the sulfonamide (or sulfamide) with a soluble acidic metal salt such as zinc sulfate.
• a soluble acidic metal salt such as zinc sulfate.
• Other metals such as aluminium, barium, bismuth, calcium, cerium, cesium, lithium, magnesium, tin, and titanium may be used in place of zinc.
• the present invention comprehends all compounds which include a sulfonylamide (-SO2NH-) group and also include an electron-withdrawing atom or moiety within five atoms of the NH group.
• the present invention further excludes such compounds in which the electron-withdrawing group is a carboxy phenyl group connected through the nitrogen atom of the sulfonylamide group or in which the sole electron-­withdrawing group is a carboxyphenyl group. Also excluded are compounds having a hydroxy group on the opposite side of the amide from the sulfonyl group of the sulfonylamide grouping.
• Particularly preferred sulfonylamide compounds in accordance with the present invention have electron withdrawing groups on both sides of the sulfonylamide grouping.
• the R and Ar groups may be optionally substituted as long as the above conditions are met.
• G is an electron withdrawing group as defined above and is not more than five atoms away from the -NH- group, with the proviso that G is not -OH or -SH when n is 1 and with the further proviso that -(R2) n -G is not and n is 0 or 1.
• sulfonamides useful in the practice of the present invention are those in accordance with formula wherein n, R1, R2 and G are as defined above with the proviso that R1 is not and with the further proviso that G is not COOH in formula II when all of the following three con­ditions apply: R2 is aryl, n is 1, and R1 does not com­prehend or include an electron-withdrawing group (as defined above for G) within 5 atoms of the NH group.
• N-mono­substituted, N'-mono or di-substituted sulfamide color developers which are also particularly useful in accordance with the present invention, are represented by formula III below: where R2, G and n are as defined above and R3 and R4 are as defined above for R1 and R2 although one of R3 and R4 may be H; furthermore, when one of R3 and R4 is H, the other may be an electron withdrawing group as defined above for G.
• N-monosubstituted sulfonamides as color developers is enhanced further by placing electron-­withdrawing groups on both sides of the sulfamoyl group.
• Preferred such compounds useful in the practice of the present invention are represented by formula IV: wherein n, R2 and G are as defined above and G' is an electron withdrawing group as defined above with respect to G.
• substituents with respect to formulae I-IV and the remainder of the generic formula as discussed above may include any functional group not specifically proscribed, it particularly may include additional -SO2NH-, alkyl, aryl and electron withdrawing (as defined above for G) groups, and may, in fact, be a polymer containing repeating units of any of the above.
• the preferred form is that of the metal salt, particularly an alkaline earth metal salt, and more particularly a zinc salt.
• the polysulfonamides prepared from aromatic disulfonyl chlorides and aromatic diamines such as poly­condensate of benzene disulfonyl chloride and p,p'-diamino­diphenylmethane (also called methylene dianiline):
• the molecular weight can be controlled by carboxymethoxybenzene sulfonyl chloride as a reaction terminator.
• Another such a poly­condensate is the product of a mild, selective hydrolysis of the methyl esters of the reaction product of two moles carboxymethoxy benzene sulfonyl chloride (CBC from Sherwin-­Williams Co.) with trimethylene glycol di-p-aminobenzoate (Polacure 740M from Polaroid Corporation), trimethylene bis (N-o-carboxylphenylsulfonyl)-p-aminobenzoate
• CBC carboxymethoxy benzene sulfonyl chloride
• Polycure 740M trimethylene glycol di-p-aminobenzoate
• trimethylene bis (N-o-carboxylphenylsulfonyl)-p-aminobenzoate trimethylene bis (N-o-carboxylphenylsulfonyl)-p-aminobenzoate
• the most preferred electron withdrawing groups are -SO2R; -COOH; -OR; -COOR; -COR; -NO2; -CN; and the halides.
• the most preferred set of electron-withdrawing groups are -SO2R; -COOH; -OR; -COOR; and -COR.
• the first stage of the reaction (as shown in reaction scheme I hereinabove) is carried out by dissolving 254.4 g (2.4 moles) of sodium carbonate (granular, 99+%, ACS reagent grade) in 1.5 liters of water.
• the solution is heated to 50°C, and at 50°C-60°C, 149.2 g or 157 ml (1 mole) of p-n-butyl­aniline (97% purity) and 281.6 g of carbomethoxybenzene sulfonyl chloride (commercially available under the name CBC) are added alternately in five portions each.
• the dual additions of the five portions of each reactant are timed at approximately 5 minute intervals.
• the temperature is raised to 80°C and held for 25 minutes, and the mixture then cooled to room temperature.
• Reaction scheme II is carried out by slowly adding the cooled reaction mixture into a 4 liter beaker containing 250 ml water and 300 ml of hydrochloric acid (37%), and equipped with an efficient stirrer, taking care that the mixture does not foam over.
• the dispersion is chilled in a refrigerator over night.
• the crude N-(p-n-butylphenyl)-o-­carbomethoxy benzene sulfonamide settles on the bottom of the beaker as a brownish, viscous mass.
• the water layer is poured off and replaced by a solution of 80g sodium hydroxide in 1.5 liter of water.
• the resulting solution is heated for 2 hours at 85°C to hydrolize the methyl ester (reaction scheme III).
• the product is isolated by filtration using a Buchner funnel, and is washed with water on the filter. The filtrate is allowed to air dry, and then pulverized to a light brown to beige powder. The yield is approximately 90% (based on butylaniline) and purity is approximately 96%.
• the proceedue could be simplified by consolidating reactions I and III, as well as II and IV, thereby avoiding the difficult to handle methyl ester.
• the procedure is an adaptation of the related preparation of p-toluenesulfonyl anthranilic acid as submitted by H. J. Scheifele, Jr. and D. F. DeTar in Organic Synthesis, Collective , volume 4, p. 37 (1963).
• the following examples show methods of formulating coatings containing the developers of the present invention for application to pressure-sensitive recording papers.
• the coatings are formulated to be porous. This permeability is usually obtained through the use of fillers, such as aluminum oxide, zinc oxide, silicon dioxide, clay or organic thixotropes.
• the binders are predominantly saturated aliphatic or aromatic compounds.
• the number of extraneous, organic, polar groups in the final, dried coating are kept to an absolute minimum. Acid groups and their metal salts are the notable exceptions.
• the color developer should be the predominant, non-fugitive, polar material in the CF coating.
• the full color developing potential appears only after the solvents (diethylene glycol, triacetin, and absorbed water) leave the film during the setting process.
• solvents diethylene glycol, triacetin, and absorbed water
• other fillers, binders and solvents can be used to complete the compositions of the present invention, all as are conventional in this art and well known.
• Example 1 An Aqueous Coating
• trimethylene bis(N-(o-carboxylphenylsulfonyl)-­p-aminobenzoate) was added to 3.7% ammonium hydroxide in 26% aqueous solution and 50% water, and mixed until completely dissolved.
• Pencoate RBB 725 an oxidized starch from Penick and Ford, Division of Pacific Resins and Chemicals, Inc.
• zinc ammonium chloride and 30% zinc oxide were added and mixed thoroughly in a high speed mixer or mill.
• the sulfonamide (or its zinc salt) may be pulverized in a ball mill, and then simply mixed with the rest of the components. If zinc salt is used, then the ZnO may be replaced by hydrated alumina.
• a kettle was charged with 24.7% diethylene glycol and 24.7% triacetin (glyceryl triacetate).
• 5% Lacros 294 an acid modified rosin resin from Crosby Chemicals, Inc.
• 30.0% n-butyl-N-(-o-carboxyphenylsulfonyl)-­p-aminobenzoate was added and, upon dissolution, 4.0% Kadox 15 (zinc oxide - chemical grade from New Jersey Zinc Co.) was added.
• the temperature was maintained at 100-105°C for one hour, although a longer heating period may be required for more inert grades of ZnO.
• a mixture of 37.0% mineral seal oil and 30.3% zinc octoate (96% pure with remainder as mineral seal oil) is heated to 100°C and then 10.2% zinc resinate (Poly Tac 100 from Reichold Chemicals Inc.) is added. After a clear solution is obtained, 18% N-(p-n-butylphenyl)-o-carboxy­benzene sulfonamide prepared by the method of the preparative example above, is added. 2.2% zinc oxide (Kadox 15 from New Jersey Zinc Co.) is dispersed into the solution and the solution is heated for 1-1/2 hours at 100-117°C. The mixture is cooled down to 80°C and 1.5% Cravalac SF is dispersed with a high speed mixer. If the texture of the ink is too coarse, the ink is passed through a 3-roll mill. The color developer is present in the form of a fine dispersion.
• the color developers in 5 and 6 are present in solution.
• Table 2 shows the color developing power of the products of examples 4, 5 and 6, as compared to a commercial product:
• a low reflectance value, R represents an intense image.
• the preferred color developer is significantly better than the comparative compound 3.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Color Printing (AREA)

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Cited By (3)

Citations (9)

• 1985
  • 1985-07-10 EP EP85304919A patent/EP0212010A1/fr not_active Withdrawn

Patent Citations (9)

Non-Patent Citations (3)

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