EP0294206A2
Expired / Lapsed
EP
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Spheroidal silica
Assignee: Unilever PLC
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Filing: 1988-06-03
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Granted: —
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Expires: 2008-06-03
Abstract
Abstract Porous spheroidal silica having a particle size in the range 1 to 400 microns, axial ratios of 1:1 to 1:12 has up to 50% by weight of the SiO₂ of included material, such as for example perfumes, flavouring materials, pigments, germicides, bactericides, fungicides, bleaching agents, skin benefit agents, therapeutic agents, dispersed in the silica as particles or droplets in the size range 0.01 to 10µm. The spheroids can be made by mixing together an aqueous, stabilised silica sol containing dispersed therein up to 50% by weight of the silica of an included material and an aqueous solution of a non-adsorbing polymer to form a phase separated system comprising silica droplets containing included material in a polymer-rich continuous phase and condensing the silica sol to aggregate the droplets to form silica spheroids containing the dispersed included material. The included material can be released in use by eg. wetting, attrition, dissolution, pH change, heating.
Inventors
- 👤 Michael Joseph Garvey
- 👤 Ian Charles Griffiths
- 👤 John Harold Stewart Rennie
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 16:36
CPC Classifications
C; C11; C11D; C11D3/00; C11D3/02; C11D3/12; C11D3/124; A; A01; A01N; A01N25/00; A01N25/12; A61; A61K; A61K8/00; A61K8/18; A61K8/19; A61K8/25; A61K9/00; A61K9/14; A61K9/141; A61K9/143; A61K9/16; A61K9/1605; A61K9/1611; A61K9/1682; A61K9/1694; A61L; A61L9/00; A61L9/015; A61L9/04; A61L9/046; A61Q; A61Q19/00; B; B01; B01J; B01J13/00; B01J13/02; B01J13/04; B01J13/046; C09; C09B; C09B63/00; C09C; C09C1/00; C09C1/28; C09C1/30; A61K2800/00; A61K2800/40; A61K2800/41; A61K2800/412; A61Q13/00; C01; C01P; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/14; C01P2006/16; C01P2006/17; C01P2006/80; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2989
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
47 words
Porous spheroidal silica having a particle size in the range 1 to 400 microns, axial ratios of 1:1 to 1:12, and up to 50% by weight of the SiO₂ of included material dispersed in the silica as particles or droplets in the size range 0.01 to 10µm.
Claim 2
Dependent Claim
47 words
Porous spheroidal silica having a particle size in the range 1 to 400 microns, axial ratios of 1:1 to 1:12, and up to 50% by weight of the SiO₂ of included material dispersed in the silica as particles or droplets in the size range 0.01 to 10µm.
Claim 3
Dependent Claim
18 words
Porous spheroidal silica according to claim 1 having a particle size in the range 1 to 200 microns.
Claim 4
Dependent Claim
38 words
Porous spheroidal silica according to claim 1 or claim 2 wherein the included material is selected from the group comprising perfumes, flavouring materials, pigments, germicides, bactericides, fungicides, bleaching agents, skin benefit agents, other therapeutic agents and mixtures thereof.
Claim 5
Dependent Claim
25 words
Porous spheroidal silica according to any one of the preceding claims wherein the included material comprises from 0.02 to 50% by weight of the silica.
Claim 6
Dependent Claim
57 words
Porous spheroidal silica according to any one of the preceding claims wherein the silica has a pore volume in the range 26 to 50% and a narrow pore size distribution in which more than 80% of the porosity is between 50 and 200% of the median pore diameter in the pore size range 20 to 1000 Å.
Claim 7
Dependent Claim
17 words
A composition including as a component porous spheroidal silica according to any one of the preceding claims.
Claim 8
Dependent Claim
77 words
Process for the preparation of porous silica spheroids containing included materials comprising mixing together an aqueous, stabilised silica sol containing dispersed therein up to 50% by weight of the silica of an included material and an aqueous solution of a non-adsorbing polymer to form a phase separated system comprising silica droplets containing included material in a polymer-rich continuous phase and condensing the silica sol to aggregate the droplets to form silica spheroids containing the dispersed included material.
Claim 9
Dependent Claim
77 words
Process for the preparation of porous silica spheroids containing included materials comprising mixing together an aqueous, stabilised silica sol containing dispersed therein up to 50% by weight of the silica of an included material and an aqueous solution of a non-adsorbing polymer to form a phase separated system comprising silica droplets containing included material in a polymer-rich continuous phase and condensing the silica sol to aggregate the droplets to form silica spheroids containing the dispersed included material.
Claim 10
Dependent Claim
39 words
Process according to claim 7 wherein the silica sol is alkali stabilised, the said polymer and the silica sol containing dispersed therein the included material are mixed together under alkaline conditions and the silica sol is condensed by acidification.
Claim 11
Dependent Claim
23 words
Process according to claim 8 wherein the sol and polymer solutions are mixed together at a pH in the range 8.0 to 10.5.
Claim 12
Dependent Claim
29 words
10 A process according to claim 8 or claim 9 wherein the silica sol is acidified by reducing the pH to between 4 and 8 in a stepwise manner.
Claim 13
Dependent Claim
32 words
A process according to any one of claims 8 to 10 wherein the non-adsorbing polymer is selected from the group comprising sodium dextran sulphate, sodium polyacrylate, sodium carboxymethyl cellulose and mixtures thereof.
Claim 14
Dependent Claim
44 words
Process according to claim 7 wherein the silica sol is acid stabilised, the said polymer and the silica sol containing dispersed therein the included material are mixed together under acid conditions and the silica sol is condensed by raising the pH of the sol.
Claim 15
Dependent Claim
37 words
Process according to claim 12 wherein the silica sol and polymer solutions are mixed together at a pH between 0 and 4.0 and the silica sol is condensed by raising the pH to between 4.0 and 8.0.
Claim 16
Dependent Claim
50 words
Process according to claim 7 wherein the silica sol is acid stabilised, the said polymer and the silica sol containing dispersed therein the included material are mixed together at a pH betwen -1.0 and 4.0 and the silica sol is condensed by maintaining the silica sol between 0 and 4.0.
Claim 17
Dependent Claim
26 words
Process according to any one of claims 12 to 14 wherein the non-adsorbing polymer is selected from the group comprising dextran, polyacrylic acid and mixtures thereof.
Claim 18
Dependent Claim
28 words
A process according to any one of claims 7 to 15 wherein the polymer concentration to induce phase separation is 0.1 to 20% by weight of the mixture.
Claim 19
Dependent Claim
39 words
A process according to any one of claims 7 to 16 wherein the included material is selected from the group comprising perfumes, flavouring materials, pigments, germicides, bactericides, fungicides, bleaching agents, skin benefit agents, other therapeutic agents and mixtures thereof.
Claim 20
Dependent Claim
27 words
A process according to any one of claims 7 to 17 including admixing the included material with the silica sol prior to contact with the non-adsorbing polymer.
Claim 21
Dependent Claim
26 words
A process according to any one of the preceding claims including incorporating the porous spheroidal silica having the included material as a component in a composition.
References Cited (Backward Citations)
No citation records indexed.
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