Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
  • C09C3/10—Treatment with macromolecular organic compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/36—Compounds of titanium
  • C09C1/3607—Titanium dioxide
  • C09C1/3676—Treatment with macro-molecular organic compounds
• • 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
  • C09D17/00—Pigment pastes, e.g. for mixing in paints
• • 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
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
• • 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
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
• • 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
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/41—Organic pigments; Organic dyes
• • 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
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/45—Anti-settling agents
• • 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
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/65—Additives macromolecular
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/51—Particles with a specific particle size distribution
  • C01P2004/52—Particles with a specific particle size distribution highly monodisperse size distribution
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values

Definitions

• This invention relates to pigment wetting and dispersing agents, pigment grind dispersions, pigment-encapsulating dispersions, and to pigmented paints and other coating compositions.
• Titanium dioxide is a widely-used but increasingly expensive pigment in paints and other coating compositions. In many paint formulations titanium dioxide represents the single most expensive raw material. A number of techniques and ingredients have been suggested for reducing the amount of titanium dioxide in coating composition formulations while still providing acceptable light scattering or opacity.
• One such ingredient is EVOQUETM Pre-Composite Polymer supplied by Dow
• EVOQUE products are presently available in four grades (EVOQUE 1140, EVOQUE 1180, EXP-4340 and EXP-4463) that are said to have differing degrees of reactivity towards titanium dioxide.
• EVOQUE pre-composite polymer "combines with Ti02 to form a polymer-pigment composite which improves both the wet and dry hiding efficiency of the pigment.” Paints or other coating compositions made from such a composite may attain a given degree of pigment hiding at a somewhat reduced titanium dioxide pigment level, or may attain a somewhat increased degree of pigment hiding at a given titanium dioxide pigment level.
• the potential savings in titanium dioxide raw material costs and the potential benefits in pigment hiding efficiency are offset by the EVOQUE product cost.
• a pigment grind dispersion comprising a mixture of a carrier, pigment particles, a polymeric dispersing agent having polymer backbone, and a zwitterionic polymer side chain comprising anionic and cationic groups.
• a pigment-encapsulating polymer dispersion including a mixture of a carrier, pigment particles, the
• particles being at least partially encapsulated by at least one polymer layer, and a polymeric dispersing agent having a polymer backbone, and a zwitterionic
• polymer side chain comprising anionic and cationic groups.
• the description provides, in yet another aspect, a method for making a pigment grind dispersion.
• the method includes steps of mixing a carrier, pigment particles, and a polymeric dispersing agent having a polymer backbone, and a zwitterionic polymer side chain comprising anionic and cationic groups.
• the present description provides, in a further aspect, a method for making a pigment-encapsulating polymer dispersion.
• the method includes steps of forming a dispersion of a carrier, pigment particles, and a polymeric dispersing agent having a polymer backbone, and a zwitterionic polymer side chain comprising anionic and cationic groups.
• this is followed by including in or adding to the dispersion one or more ethylenically unsaturated monomers and a free-radical initiator, and polymerizing the ethylenically unsaturated monomers to at least partially encapsulate the pigment particles with at least one polymer layer.
• the present invention provides, in a further aspect, a coating composition that includes a dispersion of a carrier, pigment particles, the pigment particles being at least partially encapsulated by at least one polymer layer, and a polymeric dispersing agent having a polymer backbone, and a zwitterionic polymer side chain comprising anionic and cationic groups.
• the composition also includes one or both of a film- forming binder containing a polymer other than the encapsulating polymer, or one or more standard paint formulation additives.
• the disclosed dispersions, methods and coating compositions may comprise, consist essentially of, or consist of the recited ingredients.
• the carrier comprises water
• the pigment particles comprise titanium dioxide particles
• the polymer backbone comprises a vinyl chain-growth polymer
• the anionic group comprises a sulfonate group
• the cationic group comprises a quaternary ammonium group
• the at least partially encapsulated pigment particles are self-coalescing at room temperature without requiring the presence of a film forming binder containing a polymer other than the chain-growth polymer.
• the disclosed polymeric dispersing agents may provide efficient pigment wetting and dispersion using relatively low and thus economical raw material amounts (for example, pigment, polymeric dispersing agent and chain growth polymer amounts).
• compositions desirably provide good pigment particle wetting, and improved pigment dispersion in the final dried film, especially in titanium dioxide-containing latex paints, where improved dispersion leads to improved pigment hiding efficiency.
• a coating composition that contains “a” carrier or “an” optional surfactant means that the coating composition may include “one or more” carriers and “one or more” optional surfactants.
• anionic group when used in respect to a monomer or a polymer side chain means an organic group having a net negative charge, and preferably a pH- independent net negative charge, when dissolved or dispersed in an aqueous carrier.
• binder when used in respect to a liquid coating composition means a film-forming natural or synthetic polymer suitable for use in such a composition (if need be, accompanied by a suitable coalescent).
• bulk polymer means a polymer formed from a homogeneous reaction mixture made by dissolving a suitable initiator in one or more reactive monomers and not requiring the presence of a solvent to carry out polymerization.
• carrier when used in respect to a pigment grind dispersion or coating composition means a volatile dispersant or other vehicle for the remaining components of the dispersion or composition.
• cationic group when used in respect to a monomer or a polymer side chain means an organic group having a net positive charge, and preferably a pH-independent net positive charge, when dissolved or dispersed in an aqueous carrier.
• emulsion polymer means a polymer formed from a
• heterogeneous reaction mixture initially in the form of an emulsion containing water, one or more monomers and an emulsifying agent (e.g., a surfactant).
• an emulsifying agent e.g., a surfactant
• pigment-encapsulating polymer dispersion refers to pigment particles at least partially encapsulated by a polymeric layer. The term is used interchangeably with “polymer-encapsulated pigment dispersion.”
• film-forming when used in reference to a water-insoluble polymer means that an aqueous dispersion of the polymer (if need be, accompanied by a suitable coalescent) can be formed, coated in a thin wet layer (e.g., of about 25 ⁇ thickness, and if need be at a temperature above room temperature) on a suitable substrate or support, and dried or otherwise hardened, to form a substantially continuous coating over the substrate or support.
• a thin wet layer e.g., of about 25 ⁇ thickness, and if need be at a temperature above room temperature
• contrast ratio means a value determined by casting an
• Appearance Measurement 8th Edition, and dividing the L* value measured over the black portion by the L* value measured over the white portion.
• the term "functional" when used with respect to an organic group in a monomer or polymer means a group enabling such monomer or polymer to participate in a chemical reaction, or to assist in suspending or dispersing pigment in a carrier.
• group and “moiety” are used to differentiate between chemical species that allow for substitution or that may be substituted and those that do not allow or may not be so substituted.
• group when the term “group” is used to describe a chemical substituent, the described substituent includes the unsubstituted group and that group with O, N, Si, or S atoms, for example, in the chain (e.g., as in an alkoxy group) as well as that group with carbonyl or other conventional substituents.
• moiety is used to describe a chemical compound or substituent, only an unsubstituted chemical material or substituent is intended to be included.
• alkyl group is intended to include not only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t- butyl, and the like, but also alkyl substituents bearing further substituents known in the art, such as hydroxy, alkoxy, alkylsulfonyl, halogen atoms, cyano, nitro, amino, carboxyl, etc.
• alkyl group includes ether groups, haloalkyls, nitroalkyls, carboxyalkyls, hydroxyalkyls, sulfoalkyls, etc.
• alkyl moiety is limited to the inclusion of only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl, and the like.
• alkyl group encompasses the term “alkyl moiety”, and the disclosure of any particular group is also intended to be an explicit disclosure of the corresponding moiety of that particular group.
• intervening when used with respect to the number of atoms between two organic functional groups refers to the number of atoms in the shortest path between such groups, not counting atoms of such groups.
• latex when used in respect to a polymer means an emulsion of polymer particles in water in which the polymer is not itself capable of being dispersed in water; rather, a latex polymer requires a secondary emulsifying agent (e.g., a surfactant) to form the emulsion.
• a secondary emulsifying agent e.g., a surfactant
• aqueous polymer dispersion aqueous polymer dispersion
• low VOC when used with respect to paints and other coating compositions means that the coating composition contains less than about 1 wt. percent volatile organic compounds, preferably less than about 0.5 wt.% volatile organic compounds, more preferably less than about 0.05 wt. % volatile organic compounds and most preferably less than about 0.005 wt. % volatile organic compounds based upon the total coating composition weight.
• the term "monomer” means a material that can be reacted, as need be in the presence of a suitable initiator or comonomer, to form a polymer containing three or more repeating units derived from the monomer or comonomer.
• multistage when used with respect to a latex means the latex polymer was made using discrete charges of two or more monomers or was made using a continuously- varied charge of two or more monomers.
• a multistage latex will not exhibit a single Tg inflection point as measured using DSC.
• a DSC curve for a multistage latex made using discrete charges of two or more monomers may exhibit two or more Tg inflection points.
• a DSC curve for a multistage latex made using a continuously- varied charge of two or more monomers may exhibit no Tg inflection points.
• a DSC curve for a single stage latex made using a single monomer charge or a non- varying charge of two or more monomers may exhibit only a single Tg inflection point.
• Tg inflection point may sometimes be detected on closer inspection, or the synthetic scheme used to make the latex may be examined to determine whether or not a multistage latex would be expected to be produced.
• pigment when used in respect to a coating composition or pigment grind dispersion means a particulate material which imparts one or more of color (including white or black), or other visual or performance effects to the composition or dispersion.
• the term pigment includes, without limitation, extender pigments, opacifying pigments, tinting pigments, etc.
• extender pigment or “filler” refers to an inert, usually colorless and semi-transparent pigment used in a coating composition to fortify and lower the total cost.
• An “opacifying pigment” refers to one or more pigments added to a paint composition to make it opaque.
• opaque means that a dry film of the coating composition has a contrast ratio greater than 95% at a 51 ⁇ (2 mil) dry film thickness.
• an extender pigment is assumed to have a refractive index of less than about 1.8, whereas an opacifying pigment is assumed to have a refractive index of greater than about 1.8.
• polymer includes both homopolymers and copolymers (viz., polymers
• the term "substantially free of means containing less than about 1 weight percent of the component based on the coating composition or pigment grind dispersion weight.
• waterborne when used in respect to a coating composition or pigment grind dispersion means that the major carrier is water.
• dispersion or coating composition means that the major carrier is a non-aqueous solvent or a mixture of non-aqueous solvents.
• water-dispersible when used in respect to a polymer means that without requiring the use of a separate surfactant, the polymer is itself capable of being dispersed into water, or water can be added to the polymer to form an
• Such water-dispersible polymers may include nonionic or ionic functionality on the polymer to assist in rendering the polymer water-dispersible.
• a water-soluble composition i.e. a highly hydrophilic polymer composition or system
• these external acids are not secondary emulsifying agents (e.g., surfactants) such as are used to form a latex polymer emulsion.
• secondary emulsifying agents e.g., surfactants
• zwitterionic when used in respect to a monomer or a polymer side chain means the monomer or the polymer side chain has at least one anionic group and at least one cationic group.
• a variety of pigment particles may be employed in the disclosed dispersions, methods and coating compositions.
• the particles provide light scattering sites within a dried film of the disclosed coating compositions, and impart hiding or opacity to the dried film.
• the light scattering ability of the pigment is described in terms of its refractive index. Accordingly, in an aspect, pigment particles described herein have a broad range of refractive indices, from about 1.2 to about 2.7. Without limiting to theory, extender pigments will generally have refractive index of less than about 1.8, while opacifying pigments will have refractive index of greater than about 1.8.
• Exemplary pigment particles include opacifying pigment particles such as treated or untreated inorganic pigments and mixtures thereof, for example metallic oxides including titanium dioxide, iron oxides of various colors (including black); other oxides including zinc oxide, antimony oxide, zirconium oxide, chromium oxide, and lead oxide; sulfates, sulfides and mixtures thereof including barium sulfate, zinc sulfide and lithopone; and metallic flakes such as aluminum flakes, pearlescent flakes, and the like.
• Representative pigments may have a variety of forms, for example rutile, anatase and Brookite forms in the case of titanium dioxide pigments.
• the pigment particles may have a variety of shapes and sizes but desirably will scatter photons having wavelengths in the spectral region from about 300 nm to about lOOO nm, such as the infrared region from about 700 to about 1000 nm, the visible spectral region from about 380 nm to about 700 nm, or portions or combinations thereof.
• Suitable pigment particle shapes include spherical shapes, such as a regular sphere, an oblate sphere, a prolate sphere, and an irregular sphere; cubic shapes such as a regular cube and a rhombus; plate-like shapes including a flat plate, a concave plate, and a convex plate; and irregular shapes.
• Particles having spherical shapes desirably have average diameters of about 5 nm to about 5,000 nm, e.g., about lO nm to about 1,000 nm, about lOOnm to about 500 nm, about 200 nm to about 300 nm, or about 220 to about 280 nm.
• Particles having non-spherical shapes desirably have a maximum diameter of up to about 1 micrometer, e.g., up to about 500 nm or up to about 300 nm.
• the pigment particles may include one or more coatings or surface treatments, for example, inorganic or organic coatings or surface treatments such as silica, alumina, zirconia, hydrous titania, tin oxide, zinc oxide, cerium oxide, phosphate, nitrate, polyols, amines, amine salts, silicones, siloxanes and combinations thereof (for example, a silica coating and an alumina coating).
• the pigment particles may be uncoated and untreated, but may be sufficiently well encapsulated as disclosed herein so that the encapsulated pigment particles can be employed in exterior coatings while requiring reduced levels of UV absorbers, antioxidants or other weathering-resistant additives compared to coatings made from pigment particles that have not been so encapsulated.
• Suitable pigments are commercially available from a variety of suppliers including BASF, the
• Titanium dioxide pigment particles are preferred and include those made by the chloride process, those made by the sulfide process, and those made in slurry or dry forms.
• Exemplary titanium dioxide pigments include KRONOSTM 1071, 2020,2044, 2090, 2101, 2102, 2131, 2160, 2210, 2310, 4102, 4310 and 4311 from Kronos, Inc., TIONATM 595 and 596i from Millennium Specialty Chemicals Inc.
• the disclosed pigment grind dispersions may also contain a variety of extender pigments or filler materials including talcs, china clay, barytes, carbonates, silicates and mixtures thereof.
• extender pigments or filler materials including talcs, china clay, barytes, carbonates, silicates and mixtures thereof.
• Exemplary such materials include magnesium silicates, calcium carbonate, aluminosilicates, silica and various clays.
• the disclosed pigment grind dispersions may include other pigments, including dyes, treated or untreated organic pigments, glasses and mixtures thereof.
• Exemplary such materials include various carbon blacks, azo pigments, benzimidazolinones, carbazoles such as carbazole violet, indanthrones, isoindolinones, isoindolons, perylenes, phthalocyanines, quinacridones, thioindigo reds, organic pigments including plastic pigments such as solid bead pigments (e.g., polystyrene or polyvinyl chloride beads), and microsphere pigments containing one or more voids and vesiculated polymer particles (e.g., those discussed in U.S. Patent Nos. 4,427,835,
• EXPANCELTM 551DE20 acrylonitrile/vinyl chloride expanded particles from Expancel Inc.
• SIL-CELTM 43 glass micro cellular fillers from Silbrico Corporation
• FILLITETM 100 ceramic spherical particles from Trelleborg Fillite Inc.
• SPHERICELTM hollow glass spheres from Potter Industries Inc.
• 3M ceramic microspheres including grades G-200, G-400, G-600, G-800, W-210, W- 410, and W- 610 (from 3M)
• 3M hollow microspheres including 3M Performance Additives ⁇ 30 ⁇ (also from 3M)
• INHANCETM UH 1900 polyethylene particles from Fluoro-Seal Inc.
• BIPHOR aluminum phosphate from Bunge Fertilizantes S.A., Brazil.
• the pigments are used in an amount sufficient to provide a suitably tinted, and if need be, suitably opaque cured coating composition at the desired coating thickness level, e.g., at pigment volume concentrations (PVC) of about 0.25 to about 95 volume percent.
• PVC pigment volume concentrations
• the pigment particles may improve the opacity or hiding of a coating composition formulated over a wide variety of desired PVC values.
• the PVC of the disclosed coating compositions is from about 5 to about 85%, and more preferably from about 10 to about 60%.
• the disclosed pigment grind dispersions may be made by blending together the disclosed pigment particles, polymeric dispersing agent, a carrier and an optional surfactant.
• the grind process may involve deagglomeration of pigment particles (induced for example by shear or other forces in the stirred pigment grind dispersion), and the polymeric dispersing agent may help wet out the newly-exposed pigment surface area, electrostatically (or otherwise) stabilize the deagglomerated particles, and prevent or discourage them from reagglomerating.
• the polymeric dispersing agent accordingly may promote more efficient pigment particle use and increase the extent to which such particles scatter light and opacify the disclosed coating compositions.
• the polymeric dispersing agent may for example be a bulk polymer, solution polymer or a water-dispersible polymer, or an aqueous polymer dispersion, and may for example be made by polymerizing a mixture of ethylenically unsaturated zwitterionic monomer(s), and ethylenically unsaturated monomer(s) in a suitable carrier and in the presence of an initiator.
• the polymeric dispersing agent may for example represent at least about 0.1, at least about 0.2, at least about 0.3, or at least about 0.5 wt. %>, and up to about 25, up to about 10, up to about 5, or up to about 2 wt. % of the opacifying pigment particle weight.
• a variety of ethyl enically unsaturated zwitterionic monomers may be used to form the disclosed polymeric dispersing agent.
• the ethylenically unsaturated zwitterionic monomers may include one or more (and preferably one) ethylenically unsaturated group, preferably a terminal vinyl group.
• the ethylenically unsaturated zwitterionic monomers also include one or more (and preferably one) anionic group and one or more (and preferably one) cationic group.
• anionic and cationic groups provide zwitterionic polymer side chains each comprising an anionic group and a cationic group in the polymeric dispersing agent, and may help the polymeric dispersing agent assist in wetting and stabilization as discussed above.
• Exemplary anionic groups form anions in the presence of water.
• anionic groups include neutralized acid or anhydride groups, sulfate groups (e.g., -OSC ⁇
• 2- sulfonate groups e.g., -S0 2 0 "
• phosphate groups e.g., -PO 4 phosphinate groups (e.g., -POO " )
• phosphonate groups e.g., -PO 3 "
• carboxylate groups e.g., -COO-.
• Exemplary cationic groups form cations in the presence of water.
• Non-limiting examples of cationic groups include quaternary ammonium groups (e.g., -NH 3+ , -NH 2 R1+ or - NHR1R 2+ where Rl and R2 are organic groups), quaternary phosphonium groups (e.g., - PR1R2R 3+ where Rl, R2 and R3 are organic groups) or tertiary sulfate groups (e.g., SR1R 2+ where Rl and R2 are organic groups).
• quaternary ammonium groups e.g., -NH 3+ , -NH 2 R1+ or - NHR1R 2+ where Rl and R2 are organic groups
• quaternary phosphonium groups e.g., - PR1R2R 3+ where Rl, R2 and R3 are organic groups
• tertiary sulfate groups e.g., SR1R 2+ where Rl and R2 are organic groups.
• phosphobetaine (meth)acrylates and carboxybetaine (meth)acrylates including sulfobetaine methacrylate (CAS No. 3637-26-1; also known as 3- dimethyl(methacryloyloxyethyl)ammonium propane sulfonate, as N-(3-sulfopropyl)-N- (methacryloxyethyl)-N,N-dimethylammonium betaine) or as [2- (methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide), 2- methacryloyloxyethyl phosphorylcholine (CAS No.
• the ethylenically unsaturated zwitterionic monomer may for example represent at least about 0.5 wt.%, and up to about 99.5 wt. %, of the disclosed polymeric dispersing agent.
• the disclosed polymeric dispersing agent may be formed from a variety of monomers, including hydrophobic or hydrophilic monomers.
• a variety of ethylenically unsaturated hydrophobic monomers may be used to form the disclosed polymeric dispersing agent.
• hydrophobic monomers may include one or more (and preferably include one) ethylenically unsaturated groups, preferably a terminal vinyl group.
• ethylenically unsaturated hydrophobic monomers also include one or more (and preferably include one) hydrophobic group, and preferably do not include hydrophilic groups.
• the hydrophobic groups provide hydrophobic polymer side chains in the polymeric dispersing agent.
• Exemplary hydrophobic groups include alkyl groups having 3 or more carbon atoms, aryl groups, fatty acid residues, fluorocarbon groups and silicone groups.
• Exemplary ethylenically unsaturated hydrophobic monomers include n-propyl methacrylate, isopropyl methacrylate, n- butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethyl hexyl methacrylate, isodecyl methacrylate, styrene, substituted styrenes (e.g.,
• the ethylenically unsaturated hydrophobic monomer may for example represent at least about 0.5 wt. %, and up to about 99.5 wt. %, of
• the ethylenically unsaturated hydrophilic monomers may be used to form the disclosed polymeric dispersing agent.
• the ethylenically unsaturated hydrophilic monomers may include one or more (and preferably one) ethylenically unsaturated group, preferably a terminal vinyl group.
• the ethylenically unsaturated hydrophilic monomers also include one or more (and preferably one) hydrophilic group, for example an acidic group, amino group or ethylene oxide group.
• the hydrophilic groups provide hydrophilic polymer side chains in the polymeric dispersing agent, and may increase the polymeric dispersing agent water solubility, or may assist in wetting and stabilizing the dispersed pigment particles as discussed above.
• Exemplary ethylenically unsaturated acidic monomers include acrylic acid, methacrylic acid, itaconic acid, 2-sulfoethyl (meth)acrylate, sulfopropyl (meth)acrylate, styrene sulfonic acid, vinyl sulfonic acid and the salts and esters thereof.
• Exemplary esters of unsaturated acidic monomers may be formed by reacting unsaturated acids with straight chain, cyclic or aromatic alcohols or polyols or their derivatives having l or more (e.g., 1 to 18) carbon atoms, or by reacting unsaturated alcohols with straight chain, cyclic or aromatic carboxylic acids or polyacids or their derivatives having 1 or more (e.g., 1 to 18) carbon atoms.
• Exemplary salts of unsaturated acidic monomers include alkali metal and ammonium salts.
• Exemplary ethylenically unsaturated amido monomers include 2-(meth)acrylamido-2 -methyl propanesulfonic acid, methacrylamide, methoxy methacrylamide, methoxy methyl methacrylamide and n-butoxy methyl methacrylamide. Mixtures of ethylenically unsaturated hydrophilic monomers may also be employed. The ethylenically unsaturated hydrophilic monomer may for example represent about 0 to about 90 wt. % of the disclosed polymeric dispersing agent.
• the polymeric dispersing agent may if desired be formed using appropriate amounts of other ethylenically unsaturated monomers, for example acrylonitriles, vinyl ethers and other monomers that will be familiar to persons having ordinary skill in the art.
• the disclosed polymeric dispersing agents may also be formed using monomers that do not provide polymeric side chains like discussed above, provided that monomers containing precursor units which can be modified by postpolymerization reactions to provide polymer side chains like those discussed above.
• the above-mentioned U.S. Patent Application Publication No. US 2011/0137001 Al describes postpolymerization betainization that may be employed to provide polymer side chain groups like those which would have been obtained had the above-described zwitterionic monomers been employed.
• Other postpolymerization reactions for providing other polymer side chain groups like those discussed above will be apparent to persons having ordinary skill in the art.
• the polymeric dispersing agent may be formed in the presence of one or more optional chain-growth polymerization initiators (viz., catalysts).
• exemplary initiators include hydroperoxide, persulfate, peroxy and azo derivatives, and other initiators that will be familiar to persons having ordinary skill in the art.
• exemplary hydroperoxide initiators include, without limitation, cumene hydroperoxide, t-butyl hydroperoxide, hydrogen peroxide, and the like.
• Exemplary persulfate initiators include, without limitation, sodium persulfate, potassium persulfate, ammonium persulfate, and the like.
• Exemplary peroxy initiators include t-butyl peroxy-2-ethylhexanoate, di-t-butyl peroxide, di-cumyl peroxide, tertiary amyl peroxide, cumene hydroperoxide, di-n-propyl
• azo initiators include 2,2-azobis(2-methylisobutyronitrile), 2,2-azobis(2-methylbutanenitrile), 2,2- azobis(2,4-dimethyl pentanenitrile), 2,2-azobis(2,4-dimethyl-4- ethoxyvaleronitrile) and the like.
• the polymeric dispersing agent may be prepared by copolymerizing the ethylenically unsaturated zwitterionic and non-zwitterionic monomers using
• each monomer may be adjusted to provide desired performance and other characteristics, with polymeric dispersing agents derived at least in part from one or more styrenes, acrylates or methacrylates being preferred.
• the polymeric dispersing agent typically will be formed in (or may be combined with) one or more solvents or carriers.
• Exemplary solvents or carriers include esters such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, and acetone; alcohols such as methanol, ethanol, isopropanol, and butanol; glycols such as ethylene glycol and propylene glycol; ethers such as tetrahydrofuran, ethylene glycol monobutyl ether, and propylene glycol methyl ether; and mixed ether acetates such as propylene glycol methyl ether acetate, diethylene glycol monobutyl ether acetate, and the like.
• esters such as ethyl acetate and butyl acetate
• ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, and acetone
• the carrier or solvent may be water.
• the polymeric dispersing agent is a solution polymer with for example an acid number greater than about 2, greater than about 5, greater than about 10 or greater than about 20.
• the polymeric dispersing agent is water-dispersible (as provided or via the addition of an appropriate neutralization agent) and may for example have an acid number of 0 or an acid number greater than about 20, greater than about 30, greater than about 50 or greater than about 100 .
• the acid number may for example also be up to about 700, less than about 500 or less than about 300.
• Polymeric dispersing agents may also be prepared as solution polymers and then used in water-borne coating compositions by exchanging the polymerizing solvent for water after completion of solution polymerization so as to facilitate subsequent mixing of the polymeric dispersing agent and pigment particles in an aqueous carrier, or by separating the polymer from the polymerization solvent using techniques that will be familiar to those skilled in the art such as precipitating the polymer in a non- solvent and then re-dissolving the precipitate in an aqueous carrier.
• the polymeric dispersing agent may have a variety of molecular weights. Preferably the molecular weight is sufficiently small so that the polymer will have low viscosity and good pigment wetting characteristics.
• the polymeric dispersing agent may for example have a weight average molecular weight (as measured using gel permeation chromatography and a polystyrene standard) that is greater than about 500, greater than about 2,000, greater than about 5,000 or greater than about 7,000.
• the weight average molecular weight may for example also be less than about 200,000, less than about 50,000, less than about 20,000, less than about 10,000 or less than about 8,000.
• the pigment grind dispersion may for example contain about 5 to about 80 weight percent pigment, about 0.01 to about 10 weight percent polymeric dispersing agent, and about 10 to about 70 weight percent carrier. These amounts may however depend upon a variety of factors including the pigment type, density, surface area and oil absorption value.
• the pigment particles and polymeric dispersing agent may be combined using techniques that will be familiar to persons having ordinary skill in the art. Preferably, they are combined in a carrier that will become an eventual carrier for the completed coating composition, in a mixture typically referred to as a "grind".
• the grind may if desired include grinding media and other components or ingredients that facilitate pigment size reduction and dispersion.
• the grind optionally may include one or more monomers that will be eventually be used to encapsulate the dispersed pigment particles, or such monomers may be added at after the pigment particles have been dispersed in the grind.
• the pigment particles are next at least partially encapsulated by the disclosed polymer layer or layers.
• the polymer layer or layers may be a chain-growth polymer layer.
• the polymer layer or layers may be a step-growth polymer layer.
• the partial encapsulation may conveniently be performed by including in or adding to the pigment grind dispersion one or more ethylenically unsaturated monomers (such as the monomers discussed above) and an free-radical initiator (such as the initiators discussed above) and if need be additional carrier or a further carrier (such as the carriers discussed above) to form a pigment-encapsulating dispersion.
• one or more ethylenically unsaturated monomers such as the monomers discussed above
• an free-radical initiator such as the initiators discussed above
• a further carrier such as the carriers discussed above
• Exemplary ethylenically unsaturated monomers for use in forming the chain-growth polymer layer or layers include styrene, acrylates and methacrylates such as, without limitation, styrene, substituted styrenes (e.g., vinyltoluene, alpha-methyl styrene, para-methylstyrene, para-t-butylstyrene, divinylbenzene, and the like), methyl methacrylate (MMA), ethyl methacrylate, 2- hydroxyethyl methacrylate (2-HEMA), methacryloxyethyl phosphate, sulfoethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, 2-hydroxypropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 4-hydroxylbutyl meth
• dimethacrylate polyethylene glycol dimethacrylate (PEGDMA), 1,3-butylene glycol dimethacrylate, 1,6-hexane diol dimethacrylate (HDDMA), trimethylolpropane trimethacrylate (TMPTMA), tetramethylolpropane trimethacrylate,
• PEGDMA polyethylene glycol dimethacrylate
• HDDMA 1,3-butylene glycol dimethacrylate
• HDDMA 1,6-hexane diol dimethacrylate
• TMPTMA trimethylolpropane trimethacrylate
• TMPTMA tetramethylolpropane trimethacrylate
• acetoacetoxyethyl methacrylate glycidyl methacrylate, trimethylcyclohexyl methacrylate, cyclohexyl methacrylate, t-butyl cyclohexyl methacrylate, isobornyl methacrylate, t-butyl cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, the acrylate counterparts thereof and mixtures thereof.
• Additional exemplary ethylenically unsaturated monomers include acrylamides and acrylonitriles such as methacrylamide, methoxy methacrylamide, methoxy methyl methacrylamide, n-butoxy methyl methacrylamide, methacrylonitrile, and the like.
• the chain-growth polymer layer desirably is at least partially derived from one or more fatty acid (meth)acrylates, e.g., up to about 25 weight percent based on the starting ethylenically unsaturated monomers.
• the chain-growth polymer layer is a latex polymer (for example, a single stage or multistage latex polymer).
• the partial encapsulation may conveniently be performed by including in or adding to the pigment grind dispersion one or more highly- functional reactive monomers or oligomers that can form a polymer by step-growth to provide a pigment-encapsulating dispersion.
• Exemplary polymers formed by step-growth as described herein include the reaction products of one or more dibasic acids such as carboxylic acids including, without limitation, succinic acid, adipic acid, sebacic acid, a dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid, and the like with one or more polyhydric alcohols (e.g., diols, triols, tetraols, etc.) such as, without limitation, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2- butanediol, 1,3-butanediol, 1 ,4-butanediol, 2,3-butanediol, 2 -methyl- 1,2-propanediol, 1,5-pentanedio
• At least one polymer layer formed as described herein is a film- forming binder and the at least partially encapsulated pigment particles are self-coalescing at room temperature without requiring the presence of another film-forming binder and without requiring coalescing aids containing objectionable quantities of VOCs.
• the layers may be formed using a variety of methods including those described in US Patent No. 5,171,772 (Hoy et al.).
• the polymer layer or layers may for example have a calculated thickness of about 10 to about 400 nm, with the desired spacing being somewhat dependent on the pigment particle size.
• the encapsulating polymer layer desirably has a thickness of about lOO nm so as to maintain a spacing of at least about one-half the minimum wavelength of visible light (viz., at least about 200 nm) between titanium dioxide particles.
• the resulting pigment-encapsulating dispersion may optionally be combined with one or more binders or one or more coating adjuvants (such as thickeners, rheology modifiers, surfactants or coalescents) to form a finished coating.
• one or more binders or one or more coating adjuvants such as thickeners, rheology modifiers, surfactants or coalescents
• binders will be familiar to persons having ordinary skill in the art, and may be in a variety of forms including latex polymers and solution polymers, e.g., acrylic copolymers, styrene/acrylic copolymers, vinyl acetate copolymers, vinyl acetate/acrylic copolymers, vinyl versatic acid ester/acrylic copolymers, ethylene/vinyl acetate copolymers, styrene/butadiene copolymers, alkyds, polyesters, polyester urethanes, drying oil modified polymers such as drying oil modified polyesters and polyurethanes, polyethers, polyamides, epoxy esters, polyureas, polyurethanes, polysiloxanes, silicones, fluorinated copolymers such as vinylidene fluoride, and blends of any of the above polymeric binders.
• latex polymers and solution polymers e.g., acrylic copolymers, styrene/acryl
• the binder may include a component or components of a multicomponent (e.g., two -component) reactive system such as a component of an isocyanate-polyamine, isocyanate-polyol, epoxy- polyamine, carbodiimide-polyacid, aziridine-polyacid, melamine-polyol, or urea formaldehyde-polyol coating system.
• the binder may for example represent about 5 to about 99 volume percent of the dried coating volume.
• the volume solids, as defined by the fractional volume of dry ingredients in an as-supplied coating composition may for example represent about 5 to about 80 volume percent of the coating composition.
• the pigment volume concentration may for example represent about 0.1 to about 95 volume percent of the coating. In some embodiments, the pigment volume concentration desirably is about 0.1 to about 30 volume percent, about 0.5 to about 25 volume percent, or about 1 to about 25 volume percent.
• the glass transition temperature for the polymeric binder may for example be about -130 to about 350 °C, preferably about -20 to about 150 °C, and more preferably about -10 to about 100 °C.
• the coating composition viscosity may for example be about 10 to 100,000 cps at 25° C as measured using a BROOKFIELDTM viscometer and RTV Spindle No.4 operated at 20 rpm.
• thickeners include sedimentation inhibitors, hydrophobic ethoxylated urethane resin (HEUR) thickeners, hydrophobically- modified, alkali-soluble or alkali- swellable emulsion (HASE) thickeners), cellulosic thickeners, polysaccharide thickeners and mixtures thereof.
• HEUR hydrophobic ethoxylated urethane resin
• HASE alkali-soluble or alkali- swellable emulsion
• cellulosic thickeners include NATROSOLTM 250 and the AQUAFLOWTM series from
• the disclosed coating compositions preferably contain about 0.1 to about 10 or about 0.5 to about 3 weight percent thickener or rheology modifier based on the final coating composition weight.
• Exemplary surfactants include anionic, cationic, amphoteric and nonionic surfactants.
• Commercially-available surfactants or dispersants include the
• TAMOLTM series from Dow Chemical Co. nonyl and octyl phenol ethoxylates from Dow Chemical Co. (e.g., TRITONTM X-45, TRITON X-100, TRITON X-114, TRITON X-165, TRITON X-305 and TRITON X-405) and other suppliers (e.g., the T-DET N series from Harcros Chemicals), alkyl phenol ethoxylate (APE) replacements from Dow Chemical Co., Elementis Specialties, and others, various members of the SURFYNOLTM series from Air Products and Chemicals, (e.g.,
• SURFYNOL 104 SURFYNOL 104, SURFYNOL 104A, SURFYNOL 104BC, SURFYNOL 104DPM, SURFYNOL 104E, SURFYNOL 104H, SURFYNOL 104PA, SURFYNOL
• SURFYNOL 104S SURFYNOL 2502, SURFYNOL 420, SURFYNOL 440, SURFYNOL 465, SURFYNOL 485.
• SURFYNOL 485 W SURFYNOL 82, SURFYNOL CT-211, SURFYNOL CT-221, SURFYNOL OP-340, SURFYNOL PSA204, SURFYNOL PSA216, SURFYNOL PSA336, SURFYNOL SE and SURFYNOL SE-F), various fluorocarbon surfactants from 3M, E.I. DuPont de Nemours and Co. and other suppliers, and phosphate esters from Ashland, Rhodia and other suppliers. When a surfactant is present, the disclosed coating
• compositions preferably contain about 0.1 to about 10 weight percent and more preferably about 1 to about 3 weight percent surfactant based on the total
• Coalescents may assist in coalescing the encapsulated pigment particles or optional further film-forming polymer into a continuous film.
• Exemplary coalescents include benzoates such as alkyl benzoates, monobenzoates and dibenzoates;
• hexanoates such as OPTIFILMTM 400 tri(ethylene glycol) bis(2-ethylhexanoate) from Eastman Chemical Co.; dioctyl maleate; oleic acid propylene glycol esters such as EDENOLTM EFC-100 from Cognis having the formula
• coalescents that may be added to water-borne embodiments include VOCs including glycol ethers, organic esters, aromatic compounds, and ethylene or propylene glycols.
• the disclosed coating compositions preferably contain about 0.05 to about 10 or about 0.05 to about 5 weight percent coalescent based on the final coating composition weight.
• the disclosed coating compositions may contain a variety of other adjuvants that will be familiar to persons having ordinary skill in the art. Representative adjuvants are described in Koleske et al, Paint and Coatings Industry, April, 2003, pages 12-86.
• adhesion promoters include adhesion promoters; anti-cratering agents; antioxidants; biocides, fungicides, mildewcides and preservatives (e.g., BUSANTM 1292 from Buckman Laboratories, Inc., NOPCOCIDETM N-40D from Cognis, KATHONTM LX from Rohm & Haas, and POLYPHASETM 663, POLYPHASE 678 and POLYPHASE PW-40 from Troy Corporation); buffers; curing indicators; defoamers; heat stabilizers; humectants; leveling agents; light stabilizers (e.g., hindered amine light stabilizers such as
• TINUVINTM 123-DW and TINUVIN 292 HP from Ciba Specialty Chemicals TINUVINTM 123-DW and TINUVIN 292 HP from Ciba Specialty Chemicals
• reactive diluents e.g., TINUVIN 234 and TINUVIN 1130 from Ciba Specialty Chemicals
• ultraviolet light absorbers e.g., TINUVIN 234 and TINUVIN 1130 from Ciba Specialty Chemicals
• waxes e.g., AQUACERTM 593 from Altana, HYDROCERTM 303 from Shamrock Technologies, Inc. and
• MICHEMTM Emulsion 32535 from Michelman, Inc.
• wetting agents e.g., BYKTM 346 and BYK 348 from Altana, PENTEXTM 99 from Rhodia and TROYSOL LACTM from Troy corporation
• types and amounts of these and other adjuvants typically will be empirically selected.
• the pigment-encapsulating dispersions preferably are universal
• the pigment-encapsulating dispersions may be used to form or may be added to a variety of coating
• compositions including primers, primer surfacers, topcoats (including monocoats), and basecoats for clearcoat/basecoat finishes.
• These coating compositions may contain crosslinking agents including blocked isocyanates, alkylated melamines, polyisocyanates, epoxy resins, and the like, and may be solvent-borne or water- borne.
• a variety of vehicles or carriers may be employed in solvent-borne or water-borne embodiments. Exemplary solvents and carriers include those mentioned above.
• the disclosed coating compositions preferably are low VOC dispersions containing 0.01 to less than 5 weight percent VOCs, more preferably 0.01 to less than 2.5 weight percent VOCs, and most preferably 0.01 to less than 0.5 weight percent VOCs based upon the total liquid composition weight.
• the disclosed coatings may be applied to a variety of substrates.
• Exemplary substrates include cement, cement fiberboard, concrete, metal, plastic and wood (including monolithic, engineered and veneered wood).
• the dried or hardened paints and stains may be evaluated using a variety of measurements including adhesion (as measured for example using ASTM D3359-07), block resistance (as measured for example using ASTM D4946-89, Reapproved 2003), chalking (as measured for example using ASTM D4214-07), cracking (as measured for example using ASTM D661-93), contrast ratio (CR, measured as described above), dirt retention (as measured for example using ASTM D3719- 00), fading or color change (as measured for example using ASTM D2244-11), gloss or loss of gloss (as measured for example using ASTM D523-08), impact resistance (as measured for example using ASTM D2794-93, Reapproved 2010), low temperature coalescence (LTC, as measured for example using ASTM D3793- 06), pendulum hardness (as measured for example using ASTM D-4366-
• a 173.92 g portion of deionized water and 1.94 g of Rhodacal DS-4 were added to a four-neck 2L flask equipped with a condenser, mechanical stirring blade, nitrogen purge adaptor and a thermocouple and heated to 82°C. While at this temperature and stirring under nitrogen, 28.93 g of a monomer pre-emulsion comprising 49.61 g deionized water, 8.01g of Rhodacal DS-4, 72.78 g of BA, 121.29 g of SBMA, 36.39 g of MAA, and 1.21 g of 2ME were added to the reaction flask.
• a 100.45 gportion of deionized water was added to a four neck 1L kettle equipped with a condenser, mechanical stirring blade, nitrogen purge adaptor and 2 hole rubber septum. The kettle was purged with nitrogen for 30 minutes at 91°C. While at this temperature and under mechanical stirring, a monomer solution made from 6.01 g DMAEMA-BzCl, 10.00 g SBMA, 3.03 g MAA, 0.10 g 2ME, 0.20 gAPS and 50.04 g deionized water was added over 31 minutes. A chaser solution made from 0.15 g APS and 9.89 g deionized water was added over 11 minutes. The reaction mixture was held at 90°C for another 100 minutes to remove excess initiator. The NVM was determined to be 1 1.30%.
• a titanium dioxide dispersion was prepared by the gradual addition of 500.0 g TI-PURETM R706 titanium dioxide over five minutes to a stirred aqueous solution containing 21.8 g of the Preparatory Example 1 zwitterionic copolymeric dispersing agent aqueous dispersion diluted with 125.3 g deionized water. This mixture was stirred at high speed for an additional 30 minutes, then diluted to 73% NVM with 51.5 g of deionized water to yield a titanium dioxide slurry containing 71.57 wt.% titanium dioxide and 1.43 wt.% copolymeric dispersing agent.
• a titanium dioxide grind dispersion was prepared by the gradual addition of 750.30 g TI-PURETM R706 titanium dioxide over 5 minutes to a stirred aqueous solution containing 109.49 g of the Preparatory Example 4 polymeric dispersing agent solution diluted with 191.55 g deionized water. This mixture was stirred at high speed for an additional 60 minutes to yield a titanium dioxide slurry containing 71.4 wt. % titanium dioxide and 1.14 wt.% polymeric dispersing agent.
• Rhodacal DS-4 surfactant was fed over 20 minutes and a concurrent reducer mixture fed over 120 minutes.
• the reducer mixture contained 2.49 g of FF6 reducing agent in 81.25 g of deionized water.
• the first monomer emulsion was rinsed with 10.0 g of deionized water and immediately followed by the addition of a second monomer emulsion containing 150.77 g BA, 106.53 g MMA, 2.71 g MAA, 49.07 g of Rhodacal DS-4, 51.46 g of deionized water, and 3.61 g of tBHP.
• the second monomer feed was fed over 84 minutes and rinsed with 15.0 g of deionized water.
• the pH of the product was adjusted to about 8.2 via aqueous ammonium hydroxide addition.
• the reaction product was an encapsulated titanium dioxide latex with virtually no coagulum or reactor fouling containing 55.7% NVM.
• the first and second monomer emulsions were in a 20:80 volumetric ratio, and the redox initiator feed contained 1.0 wt. % tBHP and 0.76 wt.% FF6 based on the total monomer weight.
• the pH of the product was adjusted to about 9 via aqueous ammonium hydroxide addition.
• the reaction product was an encapsulated titanium dioxide latex having a 470 nm average particle size with a monomodal particle size distribution and containing 55.5% NVM.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Paints Or Removers (AREA)

Priority Applications (4)

Applications Claiming Priority (4)

Related Child Applications (1)

Publications (1)

Family

ID=52346750

Family Applications (1)

Country Status (4)

Cited By (8)

Families Citing this family (7)

Citations (5)

Family Cites Families (9)

• 2014
  • 2014-07-18 CN CN201480040853.6A patent/CN105377999B/zh active Active
  • 2014-07-18 WO PCT/US2014/047188 patent/WO2015010016A1/en active Application Filing
  • 2014-07-18 EP EP14826975.6A patent/EP3022261A4/de active Pending
  • 2014-07-18 AU AU2014290450A patent/AU2014290450B2/en active Active

Patent Citations (5)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events