Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/16—Writing inks

Definitions

• a ' finely divided pigment component is maintained in a dispersed state in an aqueous ink composition by the use of a suspending agent comprising a water-soluble amine salt of a copolymer comprising 50 mol percent or more of a polymerizable hydrophobic monomer such as styrene along with less than 50 mol percent of acrylic acid or methacryli ⁇ acid.
• a suspending agent comprising a water-soluble amine salt of a copolymer comprising 50 mol percent or more of a polymerizable hydrophobic monomer such as styrene along with less than 50 mol percent of acrylic acid or methacryli ⁇ acid.
• the particulate predispersed pigment is formulated in an aqueous ink along with an alkaline material which solubilizes the resin or polymer encapsulating the pigment thus allowing the pigment to be dispersed into the ink vehicle with simple shear,
• the alkaline material is selected to be absorbed into the paper or to volatilize after appli ⁇ cation of the ink to thereby cause the resin component of the predispersed pigment to become water-insoluble, resulting in a water-resistant writing trace.
• Ink smudges on the skin or fabric stains can be removed, however, simply by aqueous washing with an alkaline detergent which redissolves the resin or polymer, per- mitting removal of the ink composition.
• dry pigment may be ground into a resin solution on, for example, a sigma-blade dough mixer, starting with a highly viscous resin solution and later adding more solvent to form a paste of low viscosity which can easily be removed from the mixer.
• a third method for the producti ⁇ a of predispersed pigments involves grinding in a suitable mixer an aqueous pigment filter cake with a liquid resin or a resin solution in the so-called flushing process to make the pigment leave the aqueous phase and enter into the organic phase, after which any surplus of water is decanted off and the remaining mass ground under vacuum to remove residual water and to get maximal grinding.
• flushing catches the pigment before it has agglomerated into dry case- hardened particles , a process which once done cannot be undone.
• Techniques for forming predispersed pigments for use in this invention are well known in the art and are described, inter alia, in U.S. Patents 2,649,382 and 3,925,096.
• the resin or polymer to be employed in forming the predispersed pigments for use in this invention must be an alkali-soluble material which is insoluble in neutral or acidic water but which has carboxylic or other acid groups on the polymer chains which can be neutralized with amines or other bases to render the polymer water-soluble when the pre ⁇ dispersed pigment is stirred into water containing the alkalizing agent.
• alkali-soluble polymers include, for example, polyacrylic acid; copolymers of acrylic acid with materials such as methacrylic acid; styrene; polyvinyl chloride-polyvinyl acetate copolymers; ethyl cellulose; block copolymers which have an ABA, (AB) X or (-AB)- arrangement of A (thermoplastic e.g. styrene) and B (rubbery e.g. butadiene) blocks; the glycerol ester of hydrogenated wood rosin, styrene-maleic acid copoly ⁇ mers, and modified shellacs.
• polyacrylic acid copolymers of acrylic acid with materials such as methacrylic acid
• styrene polyvinyl chloride-polyvinyl acetate copolymers
• ethyl cellulose block copolymers which have an ABA, (AB) X or (-AB)- arrangement of A (thermo
• the predispersion of the pigment into the polymer not only simplifies subsequent ink processing but also promotes the wetting of the pigment particles by the polymer in preference to other ingredients contained in the finished ink formulation. This is in contrast to those systems in which the pigment is dis ⁇ persed into an ink vehicle consisting of polymer, fluids, and additives in which all species are competing for adsorption onto the pigment surface. It is thought that the location of polymer at the pigment surface is responsible for both the improved waterfast-was able performance of these inks and the exceptional dispersion stability resulting from both the ionic nature of the polymer and the entropic effects of the polymer chains emanating from the polymer surface.
• the predispersed pigments used in the practice of this invention may contain a broad range of proportion of pigment to polymer ranging from about 1:5 to about 5:1 by weight with optimum proportions depending upon the particular polymer used and the particle size and surface properties of the pigment employed.
• the polymer component is CARBOSET XL-44, manufactured by B. F. Goodrich which is described as an all acrylic copolymer.
• the proportion of pigment to polymer in the preferred predispersed pigments ranges from about 2:3 to about 5:2.
• any of the various pigments that are con ⁇ ventionally used in the formulation of inks for writing instruments may be likewise employed in the practice of this invention.
• organic pigments including azo, anthraquinone, condensed polyazo, thio indigo, metal complex, phthalocyanine, dioxazine, and quinacridone pigments, and inorgainc pigments such as carbon black, titanium white,and iron oxide.
• specific preferred pigments include
• the final particle size of the predispersed pigment i.e. the pigment combined with the polymer, should range from about 0.01 micron to about l ⁇ O micron with pigments ranging from about 0.02 micron to about 0.1 micron being preferred.
• the pre- dispersed pigment is stirred into water, preferably deionized, along with from about 0.5 to about 3.0% by weight of a solubilizing alkaline material capable of becoming separated from the pigment by either being absorbed into writing paper or by volatilizing after application of the ink.
• a solubilizing alkaline material capable of becoming separated from the pigment by either being absorbed into writing paper or by volatilizing after application of the ink.
• Such materials include, but are not limited to, triethylamine, ethylenediamine, 2-methylpiperazine, monoamylamine, dibutylamine, n-propylamine, isopropylamine, sodium hydroxide, ammonium hydroxide, triethanolamine, morpholine, and 2-amino-2-methyl-l-propanol.
• ink additives may be incorporated into the compositions of this invention to modify the rheological and writing properties of the inks as is well known in the art.
• these materials include the addition of surfactants such as TWEEN 20 and DOW #193 for the purpose of surface tension modification, sodium Omadine or propyl parasept as fungicides, benzotriazole as a corrosion inhibitor, and humectant materials such as glycols, urea, or thiourea to reduce dry-out problems if the pen is not promptly recapped after use.
• Example 1 The following Examples are illustrative of the preparation of the inks of this invention.
• Example 1 The following Examples are illustrative of the preparation of the inks of this invention.
• CVB-330M a predispersed acrylic resin-pigment preparation produced by Custom Chemicals of Elmwood Park, New Jersey were then added.
• the CVB-330M pigment preparation consisted of six parts of a styrenated, alkali soluble, acrylic resin and four parts of a red shade, phthalocyanine blue pigment.
• the composition was mixed for one-half hour in the Sorvall mixer and was then filtered through a 0.8 micron filter to remove coarse residual particles.
• the filter retained less than 0.25 weight percent of the total pigment preparation present.
• the resultant ink exhibited a pH of 8.5, a surface tension of 34.5 dyne/cm. and a viscosity of 2.3 cps. at 25°C.
• the ink was dispensed from pens containing polyester reservoirs through a variety of molded or extruded plastic or fiber pen nibs, as well as rolling ball type points, and provided intense, water-resistant, solvent-resistant, and light-fast ink traces which could be removed from skin with soap and water.
• the pens containing t e ink wrote out a full ink supply initially as well as after six weeks storage at ambient conditions and 60°C.
• Predisol Blue 1460 W a predispersed acrylic resin- pigment preparation, manufactured by KVK U.S.A. Inc., New Brunswick, New Jersey, were added.
• the Predisol Blue 1460 W consisted of six parts of phthalocyanine blue pigment and four parts of Carboset XL-44 alkali- soluble acrylic resin manufactured by B. F. Goodrich.
• composition was mixed for one-half hour in a 3c:r"-ll mixer with the resultant ink exhibiting a pH of 9.29, a surface tension of 31.2 dynes/cm. and a viscosity of 2.85 centipoise at 25°C.
• the ink was dispensed from pens containing polyester reservoirs through a variety of pen nibs, and provided intense, water-fast, solvent-fast, and light- fast ink traces which could be removed from skin by washing with soap and water and from cloth by washing with detergent.
• the ink was freely dispensed from the pen initially and after storage for ten months at ambient conditions.
• Ink of similar properties were compounded from pigment preparations consisting of the same polymer but containing Red 2B in place of the phthalocyanine blue.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 1985
  • 1985-05-23 EP EP19850902876 patent/EP0183795A1/de not_active Withdrawn
  • 1985-05-23 WO PCT/US1985/000975 patent/WO1986000327A1/en unknown
  • 1985-05-23 AU AU44067/85A patent/AU4406785A/en not_active Abandoned
  • 1985-06-05 PH PH32368A patent/PH22383A/en unknown
  • 1985-06-06 AR AR30064885A patent/AR242243A1/es active
  • 1985-06-17 ES ES544269A patent/ES8801694A1/es not_active Expired

Non-Patent Citations (1)

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