Methods of forming shaped articles from suspensions
View Patent ↗The invention relates to methods of forming shaped articles from suspensions which include ceramic or metallic powder, or from solutions or suspensions which include one or more pharmaceutical substances or other components. The method comprises the steps of: (a) combining solvent, polymer, cross-linking agent precursor and optional further components and placing into a mould of desired shape; (b) increasing temperature of mould contents to activate cross-linking agent; (c) allowing mould contents to solidify to sufficient extent to remove mould; (d) removing shaped article from the mould.
1. A method of forming a shaped article comprising the steps of:
(a) combining solvent, polymer, cross-linking agent precursor and optional further components and placing into a mould of desired shape;
(b) increasing temperature of mould contents to activate cross-linking agent;
(c) allowing mould contents to solidify to sufficient extent to form a shaped article; and
(d) removing the shaped article from the mould;
wherein the cross-linking agent precursor forms a multifunctional aldehyde upon temperature increase.
2. The method according to claim 1 wherein the polymer is selected from the group chitosan, polyvinylalcohol, chitin, polyacrylic acid, polyvinylacrylate, polyacrylamide, pectin, xanthan gum, polymers having amide, carboxylic acid and/or hydroxyl functionalities, and mixtures thereof.
3. The method according to claim 1 wherein the cross-linking agent precursor forms a di-aldehyde upon temperature increase.
4. A method of forming a shaped article comprising the steps of:
(a) combining solvent, polymer, cross-linking agent precursor and optional further components and placing into a mould of desired shape;
(b) increasing temperature of mould contents to activate cross-linking agent;
(c) allowing mould contents to solidify to sufficient extent to form a shaped article; and
(d) removing the shaped article from the mould,
wherein the cross-linking agent precursor is 2,5-dimethoxy-2,5-dihydrofuran (DHF).
5. The method according to claim 1 wherein the mould is filled by pouring or by injection.
6. The method according to claim 1 wherein the solvent is selected from water, ethanol, methanol, iso-propanol and mixtures thereof.
7. The method according to claim 1 wherein the optional further components include ceramic or metallic powders.
8. The method according to claim 7 wherein the ceramic or metallic powder is selected from alumina, zirconia, silica silicon nitride, silicon carbide, aluminum nitride and mixtures thereof.
9. The method according to claim 1 wherein the optional further components include one or more pharmaceutical substances.
10. The method according to claim 1 which includes further drying and/or firing steps.
11. The method according to claim 1 wherein the optional further components include one or more of dispersants, chelating agents, surfactants, salts, colouring agents and biologically active agents.
12. The method according to claim 1 wherein the shaped article is net shape or near net shape.
13. The method according to claim 1 , comprising allowing mould contents to solidify to sufficient extent to form a cross-linked shaped article in the mould.
14. The method according to claim 9 , wherein the optional further components include one or more active pharmaceutical compounds.