Method and apparatus for blowmoding capsules of polyvinylalcohol and blowmolded polyvinylalcohol capsules
View Patent ↗A capsule is formed from a PVA composition by blow moulding. Such capsules can at last provide a viable alternative to gelatin for bio-degradeable capsule containing a pharmaceutical or consumable or other substance, for example a detergent. The capsules may contain solid or liquid substances. Blow moulding apparatus suitable for forming such capsules is also disclosed and claimed.
1. An injection blow-moulded capsule having walls formed from a polyvinyl alcohol (PVA) containing composition, the walls enveloping a consumable substance, wherein the PVA composition consists essentially of 40%–80% by weight partially hydrolyzed PVA, 5 to 15% by weight of a plasticizer, 0.5% to 2.5% by weight a straight or branched chain C 12 to C 24 fatty acid amide as a lubricant and 5 to 50% of an inert or consumable filler comprising calcium carbonate.
2. A capsule according to claim 1 wherein the PVA comprises partially hydrolysed PVA having a molecular weight of at least about 10,000.
3. A capsule according to claim 1 wherein the plasticizer comprises glycerol.
4. A capsule according to claim 1 wherein the fatty acid amide comprises a C 16 to C 20 fatty acid amide.
5. A capsule according to claim 4 wherein the fatty acid amide comprises stearamide.
6. A capsule having walls formed from a polyvinyl alcohol (PVA) containing composition and containing a consumable substance, wherein the PVA composition consists essentially of 40–80% by weight partially hydrolyzed PVA, 5 to 10% by weight plasticizer, 0.5% to 2.5% of a straight or branched chain C 12 to C 24 fatty acid amide as a lubricant, 5 to 50% of an inert or consumable filler comprising calcium carbonate, and stearate as an external lubricant.
7. A capsule according to claim 1 wherein the capsule is sealed.
8. A capsule according to claim 1 wherein the substance is consumable and, wherein the PVA composition contains exclusively food grade ingredients.
9. A capsule according to claim 1 wherein the capsule has a volume of 5 cubic centimeters or less.
10. A capsule according to claim 1 wherein the capsule contains a measured dose of a pharmaceutical substance.