PEARLESCENT PIGMENT

• US 3,656,982 A
• Filed: 05/04/1970
• Issued: 04/18/1972
• Est. Priority Date: 05/04/1970
• Status: Expired due to Term

• Current Assignee: Mallinckrodt Incorporated (Mallinckrodt plc)
• Original Assignee: Douglas W. Chapman, Overley R. Dean, Wilbur H. Mckellin
• Inventors: Chapman, Douglas W., McKellin, Wilbur H., Overley, R. Dean
• Primary Examiner(s): Poer, James E.
• Application Number:
  US05/034,585
• Time in Patent Office: 715 Days
• Field of Search: 106/291,38S,38Q,38F,38N
• US Class Current: 106/415
• CPC Class Codes: C01P 2004/20 extending in two dimensions, e.g. plate-like
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: C01P 2006/20 Powder free flowing behaviour
• CPC Class Codes: C09C 1/0015 Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings
• CPC Class Codes: C09C 1/0021 comprising a core coated with only one layer having a high or low refractive index
• CPC Class Codes: C09C 2200/102 the core consisting of glass or silicate material like mica or clays, e.g. kaolin
• CPC Class Codes: C09C 2200/1087 the core consisting of bismuth oxychloride, magnesium fluoride, nitrides, carbides, borides, lead carbonate, barium or calcium sulfate, zinc sulphide, molybdenum disulphide or graphite
• CPC Class Codes: C09C 2200/401 Inorganic protective coating
• CPC Class Codes: C09C 2200/403 Low molecular weight materials, e.g. fatty acids
• CPC Class Codes: C09C 3/08 Treatment with low-molecular-weight non-polymer organic compounds C09C3/006, C09C3/048 take precedence

Abstract

The luster, compressibility and other cosmetically important properties of various pearlescent pigments are substantially improved by coating the surface of the pigment particles with a composition comprising a precipitated water-insoluble metal stearate and a surfactant.

Claims

2. A pigment according to claim 1 wherein the wetting agent is a nonionic surfactant having an HLB value in the range of 5 to 16.

3. A pigment according to claim 1 wherein the surfactant is a polyoxyethylene derivative having an HLB value of about 10.

4. A pigment according to claim 1 wherein the metal soap is an alkaline earth salt of a saturated fatty acid having 12-20 carbon atoms.

5. Method for treating a pearlescent pigment selected from bismuth oxychloride platelets, mica platelets coated witH bismuth oxychloride and mica platelets coated with titanium dioxide, which comprises suspending the pigment in water;

dispersing a water-soluble salt of a higher fatty acid in the suspension;

gradually adding to the said suspension an aqueous solution containing cations which form an insoluble soap;

adding to said suspension an aqueous dispersion of a water-insoluble surfactant; and

recovering the pearlescent pigment in the form of substantially dry free-flowing particles.

6. Method of claim 5 wherein the surfactant has an HLB value in the range of 5 to 16.

7. Method of claim 5 wherein the surfactant is a polyoxyethylene derivative having an HLB value of about 10.

8. Method of claim 5 wherein the soap is an alkaline earth salt of a saturated fatty acid having 12-20 carbon atoms.