Permeable hollow particles having an outer shell of mechanically rigid porous material
First Claim
1. A method for the preparation of permeable hollow particles having an outer shell of a mechanically rigid porous material, the size of the particles being within the range from 1 μ
- m to 5000 μ
m, the method comprising;
(a) taking impermeable, substantially spherical, hollow, particles having an outer shell of a mechanically rigid material, the outer shell comprising a member selected from the group consisting of anhydrous forms of silicon dioxide, metal silicates, metal borosilicates, metal oxides, and boric oxide, the size of the particles being within the range from 1 μ
m to 5000 μ
m, and(b) treating said hollow particles with one or more reagents selected from the group consisting of acids and bases capable of rendering said hollow particles permeable by the formation of through-going pores in the outer shell by chemical reaction or solvent/solute dissolution so as to form substantially spherical permeable hollow particles having a cavity defined by the inner surface of the outer shell, said cavity being connected with the surroundings by the through-going pores, the permeability of said particles being such as to permit chemical species to traverse their outer shell via said through-going pores, wherein step (b) is carried out at a temperature of about 20°
C. to the boiling point of said acid or base obtained under reflux conditions open to the atmosphere;
with a first proviso that, if step (b) includes treatment with hydrochloric acid, then said treatment is not employed as the only treatment or as an initial treatment when said particles of step (a) are soda-lime borosilicate glass,and with a second proviso that, if step (b) includes treatment with orthophosphoric acid, then said treatment is not employed as the only treatment or as an initial treatment when said particles of step (a) are siliceous particles obtained as a component of the fly-ash formed upon combustion in a combustion plant, andwith a third proviso that said mechanically rigid material is not a material selected from metal and alloys thereof.
1 Assignment
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Accused Products
Abstract
Permeable substantially spherical hollow particles of 1-5000 μm in size are formed having an outer shell of a mechanically rigid porous material. Pores of the shell are through-going pores that connect the inside of the particles to surroundings and allow chemical species to traverse the outer shell. To prepare the particles, impermeable hollow particles are treated with an acid or base under reflux conditions to form pores. The outer shell is formed of anhydrous forms of silicon dioxide, metal silicates, metal borosilicates, metal oxides or boric oxide. Metals and metal alloys are not used in forming the outer shell. Particles containing a polymer are formed by immersing the permeable hollow particles in a solution of components that polymerize to form the polymer, allowing the solution to partially fill the particles via the pores and polymerizing the components. The permeable particles are useful as carriers in High Performance Liquid Chromatography, gel filtration, ion exchange, affinity chromatography, immunochemical procedures, solid-phase peptide or protein synthesis, immobilization of catalysts such as enzymes and noble metals and immobilization of cells or virus particles. The particles may also be used as filtration aids, adsorbents or absorbents.
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Citations
21 Claims
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1. A method for the preparation of permeable hollow particles having an outer shell of a mechanically rigid porous material, the size of the particles being within the range from 1 μ
- m to 5000 μ
m, the method comprising;(a) taking impermeable, substantially spherical, hollow, particles having an outer shell of a mechanically rigid material, the outer shell comprising a member selected from the group consisting of anhydrous forms of silicon dioxide, metal silicates, metal borosilicates, metal oxides, and boric oxide, the size of the particles being within the range from 1 μ
m to 5000 μ
m, and(b) treating said hollow particles with one or more reagents selected from the group consisting of acids and bases capable of rendering said hollow particles permeable by the formation of through-going pores in the outer shell by chemical reaction or solvent/solute dissolution so as to form substantially spherical permeable hollow particles having a cavity defined by the inner surface of the outer shell, said cavity being connected with the surroundings by the through-going pores, the permeability of said particles being such as to permit chemical species to traverse their outer shell via said through-going pores, wherein step (b) is carried out at a temperature of about 20°
C. to the boiling point of said acid or base obtained under reflux conditions open to the atmosphere;with a first proviso that, if step (b) includes treatment with hydrochloric acid, then said treatment is not employed as the only treatment or as an initial treatment when said particles of step (a) are soda-lime borosilicate glass, and with a second proviso that, if step (b) includes treatment with orthophosphoric acid, then said treatment is not employed as the only treatment or as an initial treatment when said particles of step (a) are siliceous particles obtained as a component of the fly-ash formed upon combustion in a combustion plant, and with a third proviso that said mechanically rigid material is not a material selected from metal and alloys thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
- m to 5000 μ
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19. A method for the preparation of permeable composite particles having an outer shell of a mechanically rigid porous first material, the size of the particles being within the range from 1 μ
- m to 5000 μ
m, the inner surface of said outer shell defining a cavity in which is contained a second material, said second material comprising a homopolymer or a copolymer formed in situ within said permeable hollow particles, the method comprising;(a) taking impermeable, substantially spherical impermeable hollow particles having an outer shell of a mechanically rigid material and a cavity defined by the inner surface of said outer shell, the outer shell comprising a member selected from the group consisting of anhydrous forms of silicon dioxide, metal silicates, metal borosilicates, metal oxides, and boric oxide, the size of the particles being within the range from 1 μ
m to 5000 μ
m, and(b) treating said hollow particles with one or more reagents selected from the group consisting of acids and bases capable of rendering said hollow particles permeable by the formation of through-going pores in the outer shell by chemical reaction or solvent/solute dissolution so as to form substantially spherical permeable hollow particles having a cavity defined by the inner surface of the outer shell, said cavity being connected with the surroundings by the through-going pores, the permeability of said particles being such as to permit chemical species to traverse their outer shell via said through-going pores, (c) immersing said permeable hollow particles in a solution, in a liquid solvent, of one or more components which can polymerize to form a homopolymer or a copolymer, said solution optionally containing a polymerization catalyst or initiator, (d) allowing said solution to at least partly fill said cavity within said permeable hollow particles via said through-going pores, and (e) allowing said homopolymer-/copolymer-forming components present in the solution within said hollow particles to polymerize to form solid homopolymer(s)/copolymer(s) therein; with a first proviso that if step (b) includes treatment with hydrochloric acid, then said treatment is not employed as the only treatment or as an initial treatment when said particles of step (a) are soda-lime borosilicate glass, and with a second proviso if step (b) includes treatment with orthophosphoric acid, then said treatment is not employed as the only treatment or as an initial treatment when said particles of step (a) are siliceous particles obtained as a component of the fly-ash formed upon combustion in a combustion plant, and with a third proviso that said mechanically rigid material is not a material selected from metal and alloys thereof. - View Dependent Claims (20, 21)
- m to 5000 μ
Specification