Degradable sheet material
AssigneePolymateria Limited
InventorsChristopher Wallis, Graham Chapman, Gavin Hill
Life of this patent
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Abstract
A sheet material formed of a degradeable composition comprising 30 to 80 wt % calcium carbonate, an additive, and the balance a polymer selected from polyethylene, polypropylene and copolymers and blends thereof. The additive comprises (a) two or more transition metal compounds, (b) a mono- or poly-unsaturated C14-C24 carboxylic acid, or an ester, anhydride or amide thereof, (c) a synthetic rubber. The addition optionally comprises (d) dry starch, and/or (e) calcium oxide, and/or (f) a phenolic antioxidant stabilizer. The two or more transition metal compounds are selected from iron, manganese, copper, zinc, titanium, cobalt and cerium compounds and the transition metals in the two or more transition metal compounds are different.
Claims17
A sheet material formed of a degradable composition, the composition comprising:
- 30 to 80 wt % calcium carbonate by weight of the composition;
- an additive;
- and
- the balance a polymer selected from polyethylene, polypropylene and copolymers and blends thereof,
- wherein the additive comprises, by combined weight of the additive and the polymer:
- (a) two or more transition metal compounds in a total amount of from 0.15 to 0.6 wt %;
- (b) a mono- or poly-unsaturated C14-C24 carboxylic acid, or an ester, anhydride or amide thereof, in an amount of from 0.04 to 0.08 wt %;
- (c) a synthetic rubber in an amount of from 0.04 to 0.2 wt %;
- and, optionally:
- (d) dry starch in an amount of from 0 to 20 wt %;
- and/or
- (e) calcium oxide in an amount of from 0 to 1 wt %;
- and/or
- (f) a phenolic antioxidant stabilizer in an amount of from 0 to 0.2 wt %;
- wherein the two or more transition metal compounds are selected from iron, manganese, copper, zinc, titanium, cobalt and cerium compounds and wherein the transition metals in the two or more transition metal compounds are different.
A method of forming a container, the method comprising:
- forming a composition comprising 30 to 80 wt % calcium carbonate by weight of the composition, a polymer and an additive,
- shaping the composition to form a container,
- wherein the polymer is selected from polyethylene, polypropylene and copolymers and blends thereof, and
- wherein the additive comprises, by combined weight of the additive and the polymer:
- (a) two or more transition metal compounds in a total amount of from 0.15 to 0.6 wt %;
- (b) a mono- or poly-unsaturated C14-C24 carboxylic acid, or an ester, anhydride or amide thereof, in an amount of from 0.04 to 0.08 wt %;
- (c) a synthetic rubber in an amount of from 0.04 to 0.2 wt %;
- and, optionally:
- (d) dry starch in an amount of from 0 to 20 wt %;
- and/or
- (e) calcium oxide in an amount of from 0 to 1 wt %;
- and/or
- (f) a phenolic antioxidant stabilizer in an amount of from 0 to 0.2 wt %;
- wherein the two or more transition metal compounds are selected from ferric, manganese, copper, zinc, titanium, cobalt and cerium compounds and wherein the transition metals in the two or more transition metal compounds are different.
Dependencies are inferred from the claim text.