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WO2000001771A1 - Pigments composites possedant une meilleure capacite de diffusion de la lumiere - Google Patents

Pigments composites possedant une meilleure capacite de diffusion de la lumiere Download PDF

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Publication number
WO2000001771A1
WO2000001771A1 PCT/US1999/015230 US9915230W WO0001771A1 WO 2000001771 A1 WO2000001771 A1 WO 2000001771A1 US 9915230 W US9915230 W US 9915230W WO 0001771 A1 WO0001771 A1 WO 0001771A1
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WO
WIPO (PCT)
Prior art keywords
refractive index
high refractive
composite product
particles
pigment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1999/015230
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English (en)
Inventor
Michael C. Withiam
Donald P. Conley
Juha Kuusivaara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JM Huber Corp
Original Assignee
JM Huber Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JM Huber Corp filed Critical JM Huber Corp
Priority to AU48614/99A priority Critical patent/AU4861499A/en
Publication of WO2000001771A1 publication Critical patent/WO2000001771A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • C09C3/06—Treatment with inorganic compounds
    • C09C3/063—Coating
    • 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
    • C09C1/0081—Composite particulate pigments or fillers, i.e. containing at least two solid phases, except those consisting of coated particles of one compound
    • 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
    • C09C1/40—Compounds of aluminium
    • C09C1/42—Clays
    • 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
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
    • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
    • 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

  • the present invention relates to composite white pigment particles and manufacturing techniques for their preparation.
  • aluminosilicates are well known as paper fillers, as are various forms of clay such as kaolin. It is also known in the art to modify mineral particles by application of surface coatings of various inorganic compositions .
  • the discrete active paper pigment particles are described in the above-identified four patents as being selected from among synthetic alkali metal silicates, alkali metal aluminosilicates, alkaline earth metal alumino-silicates , alkaline earth metal silicates, alkaline earth aluminocarbonates, amorphous silicas and mixtures thereof, with substantially all the active paper pigment particles having a diameter less than one micron.
  • the processing protocol taught in the above- identified four patents generally involves producing the pigment product by preforming some of the active paper pigment coating to form a slurry of coating pigment under alkaline conditions, then adding a slurry of the mineral nuclei to the alkaline pigment slurry, followed by continuing formation of the coating pigment in the presence of the mineral nuclei, with the reaction mixture always maintained under alkaline conditions.
  • U.S. Pat. 4,537,636 describes mica platelets coated with metal oxides involving uniform co-precipitation thereon of titanium dioxide hydrate, silicon dioxide, and aluminum hydroxide .
  • U.S. Pat. 5,078,793 describes a method for preparing kaolin for use as a pigment extender of titanium dioxide pigments in plastic formulations in which a sprayable slurry is prepared comprising an aqueous hydrocolloid suspension of calcined anionic particles in admixture with a cationic polymeric reagent capable of binding to kaolin particles and making them cationic. Then, the slurry is spray dried by atomizing droplets of a pressurized mixture of the slurry with gas addition to promote droplet fluffing and fragmentation, and the frangible spray dried material thereafter is collected and dry blended with anionic surface-charged titanium dioxide which binds thereto.
  • U.S. Pat. 5,152,835 describes composite titania- calcined kaolin opacifying pigments formed of particles of titania pigment and calcined kaolin particles co- flocculated and bound together in the form of coherent aggregates by an organic cationic electrolyte.
  • U.S. Pat. 5,456,749 describes anti-discoloring pearly luster pigment comprising mica particles coated with titanium dioxide and/or titanium oxide hydrate further sequentially coated with silicon oxide and/or silicon oxide hydrate, then aluminum oxide and/or aluminum oxide hydrate, and then zinc oxide and/or zinc oxide hydrate.
  • the '749 patent also describes a process in which the various coatings are sequentially formed by dropwise addition of a metal salt providing the appropriate cations for the desired metal oxide coating with pH maintained at constant value .
  • 5,540,769 describes platelet-like colored pigments comprising platelet-shaped substrate coated with a coating layer consisting of titanium dioxide and at least one suboxide thereof, and also silica, with concentration gradients such that the titanium oxide content decreases towards the outer surface while the silica content increases towards the outer surface.
  • U.S. Pat. 5,702,519 describes a pearlescent pigment, among other things, involving a core of flaky aluminum oxide, identified therein as corundum (i.e., A1 2 0 3 ) , that contains a small amount of titanium dioxide, and the core is surface-coated with titanium oxide.
  • corundum i.e., A1 2 0 3
  • the titanium oxide surface coating is accomplished by hydrolysis of a metal salt by heating or alkali treatment, which deposits hydrated titanium oxide on the cores, followed by calcination of the coated cores at high temperatures.
  • the present invention provides for unique composite pigment materials that are endowed with enhanced light scattering and opacity properties, which are useful as an active paper pigment, filler or coating pigment.
  • a composite product in which a seed particle has an exterior surface having an anionic surface potential to which is attached a plurality of smaller sized high refractive index pigment particles having an opposite surface potential to that of the exterior surface.
  • the high refractive index pigment particles used in this invention can be any white inorganic pigment having a cationic surface charge created thereon while the exterior surface of the seed particle is anionic.
  • the high refractive index particles have a refractive index above at least about 1.6 and are present in the composite pigment product in an amount of 0.1 to 30%, by dry weight.
  • the high refractive index materials can include, without limitation, Ti0 2 , ZnO, BaO, ZrO, BaS0 4 , Al 2 0 3 , MgO, and mixtures thereof.
  • the inventive composite product is produced essentially free of any organic constituents.
  • organic encompasses carbon containing compounds other than alkali or alkaline earth carbonates.
  • discussion herein occasionally refers to attaching a plurality of high refractive index particles to a single seed particle to simplify the illustration, it is understood from a practical standpoint that a plurality of seed particles will be concurrently processed in the same way in actually practicing this invention.
  • inventive composite pigment products create improved light scattering capabilities, which, in turn, translate into significantly increased cost performance of paper products incorporating the inventive pigment material.
  • inventive composite material is especially well-suited as a filler pigment for lightweight grades of paper.
  • inventive composite pigment also can be used as a coating pigment and/or filler for other applications, such as for pigmenting rubbers, plastics, paints, lacquers, printing inks, bodycare agents and cosmetics, and so forth.
  • a method for making the composite product in which a slurry is provided containing a seed particle that has an anionically- charged exterior surface, to which is sequentially added a pH reducing agent and a plurality of high refractive index particles such that an ample pH reduction is effected in the reaction medium whereby the high refractive index pigment particles attach under aqueous conditions to the exterior surface of the seed particle. While not desiring to be bound to any particular theory at this time, it nonetheless is thought that the pH reduction brought about in the reaction medium converts the surface potential of the high refractive index particles from anionic to cationic while the seed particle retains its anionic charge such that a cationic- anionic bonding interaction occurs between the high refractive index particles and the seed particle.
  • the pH reducing agent is an inorganic reagent, such as alum, which is added to the slurry of seed particles in an amount effective to reduce the pH of said resulting slurry to a pH value of 7 or less, preferably a pH ranging from 3 to 6 , and more preferably a pH ranging from 4.0 to 5.5.
  • the inventive methodology provides for mixing of the seed particles with the surface-potential modified, high refractive index pigment particles under aqueous conditions, as opposed to dry blending, the high refractive index pigment particles are well-dispersed and have improved opportunities to disperse through the aqueous media among the seed particles to provide a high quality uniform pigment coating thereon without experiencing clumping, flocculation or agglomeration problems.
  • FIG. 1 shows scattering coefficient properties of several inventive composite product formulations versus a comparison particle.
  • FIG. 2 shows hand sheet opacity % properties of several inventive composite product formulations versus a comparison particle.
  • FIG. 3 shows hand sheet brightness properties of several inventive composite product formulations versus a comparison particle.
  • FIG. 4 shows hand sheet strike through properties of several inventive composite product formulations versus a comparison particle.
  • FIG. 5 shows a process flow diagram for preparation of a composite pigment product according to an embodiment of the present invention.
  • the seed particle that is to be coated with the high refractive index pigment particles according to this invention are solid particles, including conventional paper pigments and fillers.
  • the seed particles are formed of inorganic mineral material or inorganic amorphous material that intrinsically having an anionic surface potential.
  • These inorganic particle materials can be, for example, kaolins, calcined kaolins, kaolinites, sodium aluminosilicates, acid leached clays (e.g., bauxite), talcs, micas, serpentinite, montmorillonites, hydrated alumina, precipitated calcium carbonate (PCC) , magnesium carbonate, ground limestone, ultrafine ground limestone (UFGL) , diatomaceous earth, amorphous silicas, aluminosilicates and mixtures thereof.
  • PCC precipitated calcium carbonate
  • UFGL ultrafine ground limestone
  • diatomaceous earth amorphous silicas
  • aluminosilicates and mixtures thereof Other equivalent materials and mixtures of these materials may also be used in the invention.
  • the seed particles used in this invention generally should have an average particle size ranging from approximately 1 to 10 microns.
  • the seed particles can be unmodified aluminosilicate particles, such as those described in any one of U.S. patents 3,915,734, 3,798,046, and Reissued Patent No. 30,568, which are incorporated herein by reference for all purposes.
  • a commercially available example of this type of seed particle is an amorphous aluminosilicate product manufactured by J.M. Huber Corporation, Havre de Grace, MD, U.S.A and sold under the trademark HYDREX ® .
  • seed particles include, for example, seed particles that are pre-modified particles themselves, such as those having prior surface treatments for performance enhancement other than that additionally done in the present invention.
  • another suitable class of seed particles for use as the seed pigment particles of this invention are the composite pigment particles described in U.S. Pat. Nos . 5,262,239, 5,219,660, 5,312,485, 5,352,287, which are incorporated herein by reference for all purposes.
  • a substantially inert nucleus particle is coated with a substantially continuous uniform coating formed of discrete particles of less than one micron in size preferably selected from the group consisting of synthetic alkali metal silicates, synthetic alkali metal aluminosilicates, synthetic alkaline earth metal aluminosilicates, synthetic alkaline earth metal silicates, alkaline earth aluminocarbonates, precipitated silicas, and mixtures thereof.
  • the inert nucleus particle used includes kaolins, talcs, micas, serpertine, montmorillonites, hydrated alumina, precipitated calcium carbonate (PCC) , ultrafine ground limestone (UFGL) , diatomaceous earths, and so forth.
  • PCC precipitated calcium carbonate
  • UGL ultrafine ground limestone
  • a commercially available coated pigment product of the type described in the four identified patents is sold under the Hysnap® trademark by J.M. Huber Corporation, Havre de
  • the aforementioned type(s) of seed particles can be used alone, or in combination with a second type of seed particle.
  • An example of such a second type of seed particle is clay.
  • the clay can be used together with a composite pigment particle type as described in the above- identified particles described in U.S. Pat. Nos. 5,262,239, 5,219,660, 5,312,485, and 5,352,287, with the clay preferably comprising at least 20% by weight of the total seed pigment solids.
  • a commercially available source of this combination of pigments is distinguished by the trademark Hysnap®, and is commercially available from by J.M. Huber Corporation, Havre de Grace, MD, U.S.A.
  • the high refractive index particles used in this invention can be any white inorganic pigment.
  • the high refractive index particles have a refractive index above at least about 1.6.
  • the high refractive index materials may be selected, for example, from among high refractive index metal oxides such as Ti0 2 , ZnO, BaO, ZrO, BaS0 4 , Al 2 0 3 , MgO, as used either alone or in combinations thereof .
  • Titanium dioxide particles used in this invention can have regular or irregular particle shapes with an average particle size being approximately 0.1 to 0.5 microns, and more typically 0.2 to 0.3 microns. A titanium dioxide size in the range of 0.2 to 0.5 ⁇ m is preferred.
  • the composite pigment products of this invention should contain between 0.1 to 30%, and preferably between 1 to 15%, and more preferably between 5 to 15%, by weight, of the high refractive index pigment particle material, such as titanium dioxide, based on the total weight of the finished composite pigment product (on a dry basis) . If the amount of high refractive index pigment is too small, no significant improvements in the optical properties of the finished composite pigment will be realized, while, on the other hand, if too much high refractive index pigment is used, less than optimum light scattering will arise and undue costs are incurred. With the above considerations in mind, it is preferred that the high refractive index pigment particles coat at least 5% of the exterior surface of a seed particle.
  • the starting material pigments i.e., the seed particles
  • the pH reducing agent is first added to a slurry of the seed particles with agitation or stirring so that the reaction medium has a uniformly reduced pH provided throughout before addition of the high refractive index particles thereto.
  • a surface potential modifying reaction is performed via pH reduction in the reaction medium to create opposing surface potentials as between the seed particles and the high refractive index particles.
  • the pH of the reaction medium must be sufficently reduced such that an anionic surface potential typically present on the high refractive index particles, such as titanium dioxide, at basic pH values is converted to a cationic charge .
  • an aqueous slurry of the seed particles conveniently can be treated with the pH reducing agent during the seed particle production per se (prior to any milling) by treating the cake slurry of the raw seed particles during recovery with the pH reducing agent (e.g., alum) in amounts effective to cause the prescribed pH reduction in the slurry which, in turn, will cause a surface potential modification to high refractive index particles when subsequently added thereto.
  • the pH reducing agent e.g., alum
  • the seed particles are obtained from a supplier, they can be used in the provided slurry form or slurried, as needed, if obtained in dry form, and then sequentially subjected to steps of pH reduction and addition of the high refractive index particles.
  • the pH reducing agent used to cause the surface- potential modification of the high refractive index particles should be water-soluble or water-dispersible .
  • the pH reducing agent can be inorganic or organic in composition as long as it provides the desired function.
  • the treatment of the high refractive index particles with the pH-reduced reaction medium in the presence of the seed particles causes the high refractive index material to associate with the surfaces of the seed particles in a manner which permits the full benefit of the enhanced refractive index of the composite to be achieved.
  • alum is a preferred choice of pH reducing agent out of cost considerations.
  • other water-soluble or water dispersible inorganic pH reducing reagents useful in practicing this invention include poly aluminum silica sulfate, poly aluminum chloride, titanyl sulfate, zirconyl sulfate and mixtures thereof.
  • the addition of the inorganic pH reducing agent effectively reduces the pH of the slurry of seed particles to 7 or less, preferably to a pH of 3 to 6, and more preferably 4 to 5.5, such as in the case of alum.
  • the alum is dosed into the reaction medium at a steady rate over a relatively short period of time.
  • increasing the addition amount of alum effective to drive the pH of the reaction medium below about 4 may further increase the level of modification in surface potential of the high refractive index particles that is achieved, it nonetheless may not be desirable in cases as it can lead to undesirable amounts of sodium sulfate by-product in the reaction medium.
  • Organic surface modifying reagents can also be used in the practice of this invention, such as water-soluble or water dispersible polymers substituted with quaternary ammonium groups.
  • polyacrylamides substituted with quaternary ammonium groups could be used in this regard.
  • the pH reducing agent e.g., alum
  • the high refractive index metal oxide pigment is added to the slurry of the seed particles with agitation in a reactor or in-line mixer.
  • the pH-adjusted slurry of seed pigments first optionally can be pumped to a Cowles type mixer for introducing the high refractive index metal oxide to the pH-reduced slurry of seed particles.
  • the pH- modified slurry is pumped through an in-line mixing system with high shear.
  • a useful high shear in-line mixer can be obtained from Silverson Machines, Inc. (e.g., Models 500LS and 600LS, which are single sealed models with a Nema C-Face Motor) .
  • An optional step that can be included during the mixing of the high refractive index pigments and the seed particles in the pH-reduced medium is the addition of a small amount of an alkali solution, e.g., sodium silicate, sodium carbonate, sodium hydroxide or similar materials to the dispersion for purposes of even further enhancing the overall scattering power achieved.
  • an alkali solution e.g., sodium silicate, sodium carbonate, sodium hydroxide or similar materials
  • pH-reduction and high refractive index pigment/seed particle attachment steps are carried out at about 20 - 50°C, inclusive of ambient temperature and pressure conditions.
  • the resulting raw composite pigment product is then ground by wet dispersion milling, e.g., media milling such as pebble or bead milling, to produce finely dispersed particles.
  • This dispersion can be dried, e.g., spray dried, and dry milled if desired by conventional dry milling techniques known to one skilled in the art, such as hammer milling, pendulum milling, or other impact type milling, as used in one or multiple passes for comminuting and fine grinding.
  • extreme milling can be performed by fluid energy, air mill, jet mill or other particle to particle impact type processes.
  • the desired product composite average particle size generally is less than 7 microns, and preferably between 3-7 microns, especially where the composite product is destined for active paper pigment applications .
  • FIG. 5 Another embodiment for practicing the process of the present invention is set forth in the process flow diagram of FIG. 5.
  • This flow diagram illustrates the alternate embodiment where seed pigments supplied in slurry form have not yet been subjected to the pH reduction procedure.
  • a slurry of seed pigments from tank 1 and alum from tank 2 are combined and conducted through line 9 through screen 5 into mixer 6, e.g., an in-line mixer of the same type as described hereinabove.
  • Titanium dioxide particles, supplied from tank 3 are separately fed via line 10 using pump 4 to the outlet side of mixer 6 where the titanium dioxide particles are combined with the mixture of alum and seed pigments at the inlet side of pump 7 and before the resulting mixture is introduced to pump 7.
  • Pump 7 can be any conventional pump used for slurries.
  • the resulting raw product slurry is conducted from pump 7 to mill 8 for grinding to a desired product size.
  • the inventive composite pigment product is useful either in dry form or in slurry form depending on the specific application.
  • the slurry form of the product is attractive for many active paper pigment applications of the inventive composite product pigment.
  • an "active paper pigment” means any material which will enhance the optical characteristics of paper when incorporated therein, where optical characteristics can include light scattering, opacity, sheet brightness or other conventional standard methods of measurement of optical performance of paper. They are additionally useful to enhance the print quality of papers as determined by conventional standard methods of measurement such as print-through resistance. Papers which include the composite product of this invention used as the active paper pigments demonstrate 10% and even higher increases in light scattering coefficients, paper opacity, paper brightness and print-through resistance as compared to the untreated seed particles.
  • HYDREX ® amorphous aluminosilicate was used as the seed pigment particle.
  • Unmilled seed pigment cake slurry ( ⁇ 25% solids, ave . size of 18 microns) was conducted to a vessel into which clarified alum (48% A1 2 (S0 4 ) 3 ) was added with agitation at a rate of 10 mL/min until a pH of 4.0 in the slurry was achieved. Then, 5%, by weight (dry basis) of titanium dioxide (0.4 ⁇ m) , obtained as slurry, was injected to the inlet of a Silverson in-line mixer to provide the Ti0 2 content (dry product basis) . The slurry was then pebble milled for 2.5 hours to an average particle size (APS) of between about 4-6 ⁇ m before being analyzed for paper optical performance.
  • APS average particle size
  • EXAMPLE 1 the procedures of EXAMPLE 1 were followed, except clarified alum was added until a pH of 5.0. Then, 10%, by weight (dry basis) of titanium dioxide (0.4 ⁇ m) , obtained as slurry, was injected to the inlet of a Silverson in-line mixer to provide the Ti0 2 content (dry product basis) . The slurry was then pebble milled for 2.5 hours to an average particle size (APS) of between about 4-6 ⁇ m before being analyzed for paper optical performance.
  • APS average particle size
  • Coefficient, S values were also calculated using the appropriate equations.
  • the scattering power of the base paper and a "filled" paper permit calculation of the respective filler's scattering power.
  • the Scattering Coefficients of Examples 1-6 herein were measured using a Britt Jar screening method at an average 2% filler loading level.
  • the filler was dispersed in 1 liter of deionized water and mixed in a Britt Jar for 30 seconds. After 30-45 additional seconds, the valve was opened, vacuum applied and the filler collected on #5 Whatman filter paper. This provided an even dispersion of filler on the filter paper surface and provided a rapid means to test numerous samples.
  • the filter paper containing experimental fillers was dried at 105°C for 15 minutes. Scattering Coefficients were thereby determined using the methods above.
  • the composite pigments of EXAMPLES 1, 2 and 3 each showed superior light scattering power as indicated by higher S values, than the comparison example based on a paper filled with untreated Hydrex ® P pigment. Also, increased performance was observed with the lower pH @ end of alum addition examples where silicate was added.
  • EXAMPLE 4 In this example a composite pigment particle type as described in U.S. Pat. No. 5,262,239, in Example 2 thereof, was produced in combination with 40% Fiberex ® clay (a product manufactured by J.M. Huber Corporation, Macon, GA, U.S.A.), and this composite pigment was used as the seed pigment. Unmilled seed pigment cake slurry ( ⁇ 32% solids) containing this seed pigment was conducted to a vessel into which clarified alum (48% A1 2 (S0 4 ) 3 ) was added with agitation at a rate of 10 mL/min until a pH of 5.5 in the slurry was achieved.
  • a composite pigment particle type as described in U.S. Pat. No. 5,262,239, in Example 2 thereof, was produced in combination with 40% Fiberex ® clay (a product manufactured by J.M. Huber Corporation, Macon, GA, U.S.A.), and this composite pigment was used as the seed pigment. Unmilled seed pigment cake slurry ( ⁇ 3
  • an amorphous aluminosilicate product was used as the seed pigment .
  • Unmilled seed pigment cake slurry ( ⁇ 25% solids, ave . size of 18 microns) was conducted to a vessel into which poly aluminum silica sulfate solution (referred to hereafter as PASS) was added with agitation at a rate of 10 mL/min until a pH of 6.0 in the slurry was achieved. Then, 5%, by weight
  • a series of samples of composite pigments of this invention were prepared by the procedures of EXAMPLE 3 while using alum to reduce the seed pigment pH to 5.0, except with certain variations in the levels of Ti0 2 and in certain examples adding various amounts (by weight) of sodium silicate solution during titanium dioxide addition, as indicated in Table 5, to produce composite pigments representing this invention.
  • the produced composite pigments were then analyzed for paper optical performance using the analysis protocol described above. Reference is made thereto.
  • a Comparison Example 5 was prepared and tested based on Hydrex ® P as the pigment .
  • the superior optical properties of the composite pigment products were experimentally tested by producing handsheets. Handsheets were prepared using TAPPI standard methods and procedures well know to those trained in the art .
  • a Comparison Example 5 was also prepared and tested based on Hydrex ® P as the pigment .
  • FIGS. 1-4 graphically summarize and show the superior optical performance properties displayed by the inventive composite products as represented by Examples 7-10 versus the Comparative Example 5 containing the HYDREX ® P pigment as is, at various filler levels.
  • the increase in performance realized by use of the processing protocol of this invention is the result of improved light scattering capability imparted to the composite pigment of this invention.
  • the data also shows its superiority to a leading pigment commonly used as a filler in paper.
  • the protocol described in EXAMPLE 3 was repeated except use was made of unmilled Hysnap® cake slurry in full production scale as the seed pigment.
  • the unmilled seed pigment cake slurry ( ⁇ 35% solids, ave . size of 18 microns) was recovered and into which clarified alum (48% A1 2 (S0 4 ) 3 ) was added, with agitation at a rate, of 10 L/min until a pH of 4.5 in the slurry was achieved.
  • 7%, by weight (dry basis) of titanium dioxide (0.4 ⁇ m) obtained as slurry, was injected to the inlet of a positive displacement type pump to provide the Ti0 2 content (dry product basis) .
  • the slurry was passed through an in-line mixer, then media milled to an average particle size (APS) of about 6 ⁇ m.
  • the composite product pigment displayed excellent optical performance.
  • inventive composite pigment has been illustrated hereinabove as a paper pigment, it will be understood that the inventive composite pigment also can be used as a coating pigment and/or filler for other applications, such as for rubbers, plastics, paints, lacquers, printing inks, bodycare agents and cosmetics, and so forth.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Composite Materials (AREA)
  • Pigments, Carbon Blacks, Or Wood Stains (AREA)
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Abstract

L'invention concerne des matières de pigment composites pourvues de propriétés améliorées d'opacité et de diffusion de la lumière, utilisées comme pigments de papier actif, comme charge ou comme pigments de revêtement. L'invention concerne également un procédé unique pour fabriquer des matières de pigment composites selon lequel on réduit le pH d'un bain de réaction contenant des particules de grains et des particules à indice de réfraction élevé, ce qui a pour effet d'inverser vers le cationique le potentiel de surface des particules à indice de réfraction élevé, ce qui leur confère la capacité de s'attacher à une surface des particules de grains dans des conditions aquatiques.
PCT/US1999/015230 1998-07-07 1999-07-06 Pigments composites possedant une meilleure capacite de diffusion de la lumiere Ceased WO2000001771A1 (fr)

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AU48614/99A AU4861499A (en) 1998-07-07 1999-07-06 Composite pigments having enhanced light scattering ability

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US11085698A 1998-07-07 1998-07-07
US09/110,856 1998-07-07

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130298802A1 (en) * 2012-05-09 2013-11-14 J.M. Huber Corporation Blended opacifier for coatings and polymeric matrices
WO2014000874A1 (fr) 2012-06-28 2014-01-03 Kronos International, Inc. Pigments composites contenant du dioxyde de titane et du carbonate et procédé pour leur préparation
EP2883917A1 (fr) 2013-12-13 2015-06-17 Kronos International, Inc. Pigments composites contenant du phosphate de calcium et leur procédé de fabrication
DE102015002946A1 (de) 2015-03-10 2016-09-15 Kronos International, Inc. Aluminiumhydroxid-haltige Kompositpigmente und Verfahren zu ihrer Herstellung
EP3081602A1 (fr) 2015-04-17 2016-10-19 Kronos International, Inc. Pigments composites contenant de l'hydroxyde d'aluminium et leur procédé de fabrication
US9790379B2 (en) 2016-03-16 2017-10-17 The Sherwin-Williams Company Opacifying clusters for use in paint compositions
US10662335B2 (en) 2015-03-10 2020-05-26 Kronos International, Inc. Aluminiumhydroxide-containing composite pigments and method for production
US11453598B2 (en) 2009-08-31 2022-09-27 Colgate-Palmolive Company Surface modified pigment

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11453598B2 (en) 2009-08-31 2022-09-27 Colgate-Palmolive Company Surface modified pigment
US8876965B2 (en) * 2012-05-09 2014-11-04 J.M. Huber Corporation Blended opacifier for coatings and polymeric matrices
US9051477B2 (en) 2012-05-09 2015-06-09 J.M. Huber Corporation Blended opacifier for coatings and polymeric matrices
US20130298802A1 (en) * 2012-05-09 2013-11-14 J.M. Huber Corporation Blended opacifier for coatings and polymeric matrices
WO2014000874A1 (fr) 2012-06-28 2014-01-03 Kronos International, Inc. Pigments composites contenant du dioxyde de titane et du carbonate et procédé pour leur préparation
DE102013009635A1 (de) 2012-06-28 2014-05-22 Kronos International, Inc. Titandioxid-haltige und Carbonat-haltige Kompositpigmente und Verfahren zu ihrer Herstellung
US8858701B2 (en) 2012-06-28 2014-10-14 Kronos International, Inc. Composite pigments comprising titanium dioxide and carbonate and method for producing
EP2883917A1 (fr) 2013-12-13 2015-06-17 Kronos International, Inc. Pigments composites contenant du phosphate de calcium et leur procédé de fabrication
US10738194B2 (en) 2013-12-13 2020-08-11 Kronos International, Inc. Composite pigments containing calcium phosphate and method for their manufacture
US10662335B2 (en) 2015-03-10 2020-05-26 Kronos International, Inc. Aluminiumhydroxide-containing composite pigments and method for production
DE102015002946A1 (de) 2015-03-10 2016-09-15 Kronos International, Inc. Aluminiumhydroxid-haltige Kompositpigmente und Verfahren zu ihrer Herstellung
EP3081602A1 (fr) 2015-04-17 2016-10-19 Kronos International, Inc. Pigments composites contenant de l'hydroxyde d'aluminium et leur procédé de fabrication
US9790379B2 (en) 2016-03-16 2017-10-17 The Sherwin-Williams Company Opacifying clusters for use in paint compositions
US11001718B2 (en) 2016-03-16 2021-05-11 The Sherwin-Williams Company Opacifying clusters for use in paint compositions

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