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
  • B41M5/136—Organic colour formers, e.g. leuco dyes
  • B41M5/1366—Organic colour formers, e.g. leuco dyes characterised solely by tri (aryl or hetaryl)methane derivatives

Definitions

• This invention relates to pressure sensitive information transfer and duplicating systems and particularly to improved chemical type transfer and reproduction media for effecting duplicative image transfer on sheet material in response to selectively applied pressure and to processes for forming the same.
• Pressure sensitive image transfer media of diverse character are widely employed in the information recording and duplicating arts.
• Chemical type or so-called "carbonless" pressure sensitive transfer and duplicating systems wherein a visable image is formed by the selective chemical reaction of two essentially colorless reagents, have been long recognized as a viable expedient for the formation of duplicate copy material.
• Such systems normally broadly comprise a substrate supported coating that contains a first normally inactive chemical reagent material that is selectively transferable in response to applied pressure into a reaction providing and color producing relationship with a second normally inactive chemical reagent material contained within or comprising a second coating disposed on the surface of an interfacially contiguous second substrate.
• the coatings on a CB and a CF sheet are placed in interfacially contiguous relation and subjected to selectively applied pressure, as by the pressure of a stylus or the impact of a typewriter key on the obverse surface of the CB sheet, the operative and usually colorless chemical reagents in such coatings are brought into co-reactive relationship, as for example on the surface of the CF sheet, to produce a colored image conforming to the contour of the selectively applied pressure member.
• Such chemical type pressure sensitive transfer and duplicating systems are in widespread and expanding use at the present time for the making of multiple copies of selectively recordable duplicative information on sheet material, such as paper and the like, due, at least in part, to their basic cleanliness and to the fact that the color producing reagents are inactive until placed into operative co-reactive relationship in response to selective application of pressure.
• the application of pressure effects a rupture of the liquid dyestuff confining capsular elements in the area of applied pressure to effect a release of the dye precursor material and selective transfer of at least a portion thereof into co- reacting and color producing relationship with the electron accepting material in the contiguous coating on the CF sheet with the resulting formation of a duplicative image thereon.
• This invention may be briefly described, as an improved solvent type of CF coating material employing tri(p-phenylaminophenyl)-hydroxymethane, sometimes colloquially and less precisely identified as "spirit blue in carbinol form" as a dye precusor selectively dispersed throughout an alkaline biased carrier film.
• the principal object of this invention is the provision of an inexpensive, light and water stable dye precursor containing receptor coating for chemical carbonless copy systems.
• Another object of this invention is the provision of a receptor coating for chemical carbonless copy systems that employs tri(p-phenylamino-phenyl)-hydroxymethane as a chromogenic reagent material.
• a further object of the invention is the provision of a light and water stable receptor coating for chemical carbonless copy systems that employs tri(p-phenylamino-phenyl)-hydroxymethane dispersed throughout an alkaline biased carrier film.
• the improved CF or receptor coating comprises the solid residue of an applied alkaline biased homogeneous mixture of an evaporable non-polar hydrocarbon solvent, a chemically neutral or alkaline resinous binder, an opacifier-filler and tri(p-phenylamino-phenyl)-hydroxymethane as a dye precursor type of chromogenic reagent material.
• Such solidified CF coating is further characterized by the presence of such dye precursor in solid form and which dye precursor is insoluble in water.
• a dispersant to assist in the uniform dispersion of such dye precursor throughout the mix and a thickener to provide the requisite viscosity properties to facilitate the coating of the mix in accord with the particular requirements of the coating equipment employed.
• the evaporable liquid vehicle must be of non-polar character and a solvent for the tri(p-phenylaminophenyl)-hydroxymethane dye precursor component.
• Suitable non-polar organic solvents include acetone, toluene, heptane and naphtha, with toluene being presently preferred for use.
• a presently preferred CF coating comprises the solid residue of an applied intermix of an evaporable non-polar solvent, suitably 50 to 80 parts of toluene, having dissolved therein at least about 7 to 20 parts of a chemically neutral or alkaline resinous binder, suitable polyvinylacetate. Added thereto is about 0.1 to 0.5 parts of a dispersant and about 0.1 to 4 parts of dry potassium hydroxide to provide an alkaline bias to the mix and to minimize inadvertent color reactions in the CF coated sheets.
• an evaporable non-polar solvent suitably 50 to 80 parts of toluene, having dissolved therein at least about 7 to 20 parts of a chemically neutral or alkaline resinous binder, suitable polyvinylacetate.
• Added thereto is about 0.1 to 0.5 parts of a dispersant and about 0.1 to 4 parts of dry potassium hydroxide to provide an alkaline bias to the mix and to minimize inadvertent color reactions in the CF coated sheets.
• opacifier-fillers suitably up to about 20 parts finely divided titanium dioxide and the reminder of calcium carbonate; and about 0.5 to 5 parts of tri(p-phenylamino-phenyl)-hydroxymethane as the chromogenic reagent.
• binder is not attended with any particular degree of criticality as long as it is of chemically neutral or of alkaline character and functions as a binding agent for the opacifier-filler and the color precursor, with both of the latter being in solid form.
• a preferred binder material which is readily soluble in the above described evaporable non-polar solvent carrier comprises polyvinylacetate, suitably Vinac B-15, as manufactured by Air Products & Chemicals Company.
• a presently preferred dispersant comprises sodium salt of polymeric carboxylic acid such as Tamol 731 as manufactured by Rohm & Haas Company of Philadelphia, Pa.
• the opacifier-filler which serves both to enhance the appearance of the coating and to cooperate in the uniform distribution and spaced separation of the solid color precursor in the CF coating must also be of neutral or alkaline character.
• Such filler may suitably comprise calcium carbonate such as A lbaglos as manufatured by Chas. Pfizer & Co. This material has pH of 9.4, a specific gravity of 2.7 and an average particle size of about 0.75 microns.
• Another suitable opacifier-filler employed in conjunction with the above is Unitane 0-110 titanium dioxide as manufactured by the American Cyanamid Company. This material has a minimum TiO 2 content of 99%, a pH of about 7.7 and a specific gravity of about 3.9.
• the chromogenic reagent employed is tri(p-phenylamino-phenyl)-hydroxymethane.
• the preferred dye precursor for use in accordance with the invention is obtained from The Sherman Williams Company. As indicated in Sherman Williams technical bulletin AB-47 the preferred tri(p-phenylamino-phenyl)-hydroxy methane (therein identified as "Spirit Blue Carbinol Form"), forms in the presence of acid pH an intensely colored dye stuff known as solvent Blue (CI No. 42760).
• Transposition into or form its colorless form is solely pH responsive, with intense color being produced in an acid pH environment.
• Alkaline biasing of the coating is maintained by the selective utilization of alkaline biased constituents as set forth above and by the inclusion of small amounts of potassium hydroxide when necessary or desirable.
• a liquid mixture is first formed by intermixing the non-polar toluene solvent with the polyvinylacetate binder material, the dispersant, the potassium hydroxide (to cast the pH of the solution to the alkaline side) with continuous agitation until all solids are completely dissolved after which the organic dyestuff dye precursor material is added with continued stirring until it is dissolved.
• To the above liquid mixture is then added the requisite amounts of calcium carbonate and the titanium dioxide opacifier-filler. Such addition should be accompanied by continuous stirring of such constituents in the liquid vehicle to obtain a uniform dispersion thereof.
• the specified dye precursor can be added in its colorless form as a powder, or it can be added in its colored form as Solvent Blue 23. If the latter colored form is so utilized, the alkaline cast of the other constituents, including any necessary amounts of potassium hydroxide, will cause the dye to revert to its colorless or carbinol form in the mixture.

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

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Publications (1)

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Citations (8)

• 1982
  • 1982-04-29 EP EP82302224A patent/EP0093209A1/de not_active Ceased

Patent Citations (8)

Non-Patent Citations (1)

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