Patent US5032425A successfully refreshed from Google Patents.
US5032425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment process
Assignee: Tioxide Group Ltd
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Filing: 1990-01-09
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Granted: 1991-07-16
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Expires: 2010-01-09
Abstract
Abstract A process of coating or encapsulating an inorganic powder is described in which the powder, preferably a pigment, is dispersed in an aqueous medium and an ethylenically unsaturated monomer is polymerized in the presence of the powder and while subjecting the reaction mixture to ultrasonic vibrations. The monomer is present in an amount not exceeding 200% by weight of the powder and preferably is an acrylate or methacrylate. The powder has a cationic charge on its surface which can be generated by treatment of the surface with, preferably an aluminium salt.
Inventors
- 👤 Ian Livsey
- 👤 Rachael L. Parry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:27
CPC Classifications
C; C08; C08K; C08K9/00; C08K9/08
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
90 words
A process for the treatment of an inorganic powder which comprises polymerising a reaction mixture of an ethylenically unsaturated monomer in the presence of a dispersed inorganic powder having a cationic charge on the surface of the particles thereof, said monomer being present in an amount not greater than 200% of the weight of said powder, and subjecting the said monomer and said powder to the effect of ultrasonic vibrations during at least a part of the polymerisation of said monomer so that said particles are coated with polymerised monomer.
Claim 2
Dependent Claim
90 words
A process for the treatment of an inorganic powder which comprises polymerising a reaction mixture of an ethylenically unsaturated monomer in the presence of a dispersed inorganic powder having a cationic charge on the surface of the particles thereof, said monomer being present in an amount not greater than 200% of the weight of said powder, and subjecting the said monomer and said powder to the effect of ultrasonic vibrations during at least a part of the polymerisation of said monomer so that said particles are coated with polymerised monomer.
Claim 3
Dependent Claim
24 words
A process according to claim 1 in which the amount of the said monomer is not greater than 100% by weight of said powder.
Claim 4
Dependent Claim
23 words
A process according to claim 1 in which the amount of said monomer is from 2% to 25% by weight of said powder.
Claim 5
Dependent Claim
20 words
A process according to claim 1 in which the ultrasonic vibrations have a frequency of from 20 to 50 kHz.
Claim 6
Dependent Claim
27 words
A process according to claim 1 in which the power supplied into the reaction mixture by the ultrasonic vibrations is from 15 to 60 watts per liter.
Claim 7
Dependent Claim
14 words
A process according to claim 1 in which the inorganic powder is titanium dioxide.
Claim 8
Dependent Claim
20 words
A process according to claim 1 in which said inorganic powder is present in the form of an aqueous dispersion.
Claim 9
Dependent Claim
22 words
A process according to claim 7 in which the amount of the inorganic powder is from 150 to 300 gms per liter.
Claim 10
Dependent Claim
19 words
A process according to claim 1 in which the inorganic powder is treated with a surface charge modifying agent.
Claim 11
Dependent Claim
34 words
A process according to claim 9 in which the surface charge modifying agent is a source of a Al 3+ , Zn 2+ , Th 4+ , UO 2 2+ or Pd 2+ ions.
Claim 12
Dependent Claim
21 words
A process according to claim 10 in which the surface charge modifying agent is an aluminium salt of a mineral acid.
Claim 13
Dependent Claim
29 words
A process according to claim 9 in which the amount of the surface modifying agent is from 2.5% to 7.5% by weight of the weight of said inorganic powder.
Claim 14
Dependent Claim
20 words
A process according to claim 9 in which a cationic organic compound is used as a surface charge modifiying agent.
Claim 15
Dependent Claim
20 words
A process according to claim 1 in which the said monomer is an unsaturated carboxylic acid or an ester thereof.
Claim 16
Dependent Claim
14 words
A process according to claim 14 in which two or more monomers are copolymerised.
Claim 17
Dependent Claim
53 words
A process according to claim 1 in which said monomer is selected from the class consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, butyl acrylate, ethyl methacrylate, styrene, vinyl toluene, alpha methylstyrene, ethylene, vinyl acetate, vinyl chloride and acrylonitrile.
Claim 18
Dependent Claim
18 words
A process according to claim 1 in which said reaction mixture contains a cross-linking agent for polymerised monomer.
Claim 19
Dependent Claim
36 words
A process according to claim 17 in which the cross-linking agent is selected from the class consisting of ethylene glycol dimethacrylate, ethylene glycol diacrylate, allyl methacrylate, allyl acrylate, 1,3-butanediol diacrylate, divinyl benzene and 1,3 butanediol dimethacrylate.
Claim 20
Dependent Claim
29 words
A process according to claim 17 in which the amount of the cross-linking agent is from 10% to 50% of the total weight of the monomers to be polymerised.
Claim 21
Dependent Claim
23 words
A process according to claim 1 in which the said monomer is formed into an emulsion prior to mixing with said inorganic powder.
Claim 22
Dependent Claim
16 words
A process according to claim 1 in which the polymerisation is initiated with a water-soluble initiator.
Claim 23
Dependent Claim
19 words
A process according to claim 21 in which the initiator is a mixture of a persulphate and a metabisulphite.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-15 | 1995-01-14 | 1995-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-15 | 1999-01-14 | 1999-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-15 | 2003-01-14 | 2003-07-16 | $7700.00 | Window Closed / Lapsed |