Melt processable biodegradable compositions and articles made therefrom

Claim 1

A composition of matter comprising: a. about 10 to 70 wt. % of one or more thermoplastic polymers comprising one or more repeating units of the general formula: wherein R is independently alkyl having from about 1 to 9 carbon atoms; b. about 5 to 35 wt. % of one or more ester containing polymers, the one or more polymers having a molecular weight greater than about 10,000 and selected from the group consisting of: i. polymers with ester linkages in the backbone, the polymers comprising one or more monomeric units of the formula: wherein R₁ may be alkane or alkene having about 2 to 12 carbon atoms; and R₂ is alkane, alkene, or aryl having up to about 12 carbon atoms; and ii. polymers with pendant ester groups, the polymers comprising one or more monomeric units selected from the group consisting of the units: wherein X is independently H, Cl, alkyl having about 1 to 3 carbon atoms, aryl, acetate or hydroxyl group; R₄ is H or alkyl having from about 1 to about 2 carbon atoms; R₅ is alkyl having from about 1 to 4 carbon atoms; and c. about 0 to 30 wt. % of one or more plasticizers; and d. about 0 to 50 wt. % of an inert filler.

Claim 32

A method of preparing a biodegradable composition comprising: a. blending about 50 to 80 wt. % of destructurized starch with a hydrophobic copolymer selected from the group consisting of ethylene-vinyl acetate having a vinyl acetate molar content of from about 5 to 90 %, modified ethylene vinyl-acetate having from about 5 to 90 % of hydrolyzed acetate groups, ethylene-glycidil acrylate, ethylene-methyl methacrylate, ethylene-maleic anhydride, and mixtures thereof; b. blending the product of step (a) with a plasticizer selected form the group consisting of glycerine; polyethylene glycol; ethylene glycol; propylene glycol; sorbitol; mannitol; the acetate, ethoxylated and propoxylated derivatives of glycerine, polyethylene glycol, ethylene glycol, propylene glycol, sorbitol, mannitol; and mixtures thereof, said plasticizer is present in amount about 20 to 60 wt. % of the destructurized starch component of step (a); c. optionally blending the product of step (b) with up to about 20% urea with respect to the weight of the destructurized starch component of step (a); d. blending the product of step (c) with about 15 to 55 wt. % of unmodified starch and a water soluble plasticizer containing hydroxyl groups and having a molecular weight of less than about 1000.

Claim 33

A method of preparing a biodegradable composition comprising: a. blending about 10 to 70 wt. % of one or more thermoplastic polymers selected from the group consisting of poly(3-hydroxybutyrate) and poly(3-hydroxyvalerate) and copolymers thereof; with an amount of about 0 to 30 wt. % of a plasticizer selected from the group consisting of poly(ethylene adipate), poly(propane sebacate), poly(hexamethylene succinate), poly(hexamethylene fumarate), poly(dodecane sebacate), poly(tetramethylene azelate), and triacetate ester; b. blending the product of step (a) with an ester-containing polymer selected from the group consisting of polycapralactone, ethylene glycol adipate, propylene glycol sebacate, ethylene glycol phthalate, polyvinyl acetate, ethylene-vinyl acetate copolymers, vinyl chloride-vinyl acetate copolymers, and methacrylate copolymers; c. blending the product of step (b) with an amount of about 0 to 50 wt. % of unmodified starch having a water content of less than about 2 wt. % and a particle size of less than about 15 microns.