Biodegradable polymer compositions

• US 9,714,319 B2
• Filed: 02/05/2015
• Issued: 07/25/2017
• Est. Priority Date: 03/19/2009
• Status: Active Grant

• Current Assignee: Stratasys Incorporated
• Original Assignee: Stratasys Incorporated
• Inventors: Van Gorden, Garrett S., Cernohous, Jeffrey J.
• Primary Examiner(s): Stanley, Jane L
• Application Number:
  US14/615,009
• Publication Number:
  US 20150152217A1
• Time in Patent Office: 901 Days
• Field of Search: 524 8, 524599, 524612, 524702
• CPC Class Codes: C08G 2261/132 branched or hyperbranched
• CPC Class Codes: C08G 63/08 Lactones or lactides
• CPC Class Codes: C08G 83/005 Hyperbranched macromolecules
• CPC Class Codes: C08K 5/0033 Additives activating the degradation of the macromolecular compound
• CPC Class Codes: C08K 5/0066 Flame-proofing or flame-retarding additives
• CPC Class Codes: C08K 5/10 Esters; Ether-esters
• CPC Class Codes: C08K 5/14 Peroxides
• CPC Class Codes: C08K 5/34928 Salts
• CPC Class Codes: C08K 5/49 Phosphorus-containing compounds C08K5/0091 takes precedence
• CPC Class Codes: C08K 5/5205 Salts of P-acids with N-bases
• CPC Class Codes: C08L 101/005 Dendritic macromolecules
• CPC Class Codes: C08L 101/16 the macromolecular compounds being biodegradable

Abstract

Hyper-branched biodegradable polymers are produced by melt processing biodegradable polymers with a branching agent at temperatures that promote free radical reactions between the biodegradable polymer and the branching agent. The biodegradable compositions have an excellent balance of mechanical properties and are suitable for flame retardant applications.

Claims

1. A melt processable polymer comprising a biodegradable polymer bonded with a branching agent through free radical reactions to form a hyper-branched polymer, wherein the hyper-branched polymer is produced by melt processing the biodegradable polymer with the branching agent at temperatures that promote the free radical reactions between the biodegradable polymer and the branching agent and wherein the hyper-branched polymer is capable of a secondary melt processing procedure to produce an article having a selected shape, wherein the biodegradable polymer comprises a linear polyester and the branching agent comprises a multifunctional monomer capable of undergoing free radical hemolysis.

2. The polymer of claim 1, wherein the biodegradable polymer comprises a linear polyester.

3. The polymer of claim 2, wherein the linear polyester comprises one or more selected from the group consisting of polylactic acids, poly-L-lactic acid (PLLA), and a random copolymer of L-lactic acid and D-lactic acid.

4. The polymer of claim 1, wherein the biodegradable polymer comprises a polyester selected from the group consisting of polycaprolactone, polyhydroxybutyric acid, polyhydroxyvaleric acid, polyethylene succinate, polybutylene succinate, polybutylene adipate, polymalic acid, polyglycolic acid, polysuccinate, polyoxalate, polybutylene diglycolate, and polydioxanone.

5. The polymer of claim 1, wherein the branching agent comprises organic compounds comprising multiple ethylenically unsaturated sites.

6. The polymer of claim 5, wherein the branching agent comprises multifunctional acrylate and methacrylate compounds.

7. The polymer of claim 6, wherein the branching agent is selected from the group consisting of 1,6-hexanediol dimethacrylate, 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, glycerol trimethacrylate, glycerol triacrylate, glycerol dimethacrylate, glycerol diacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate and pentaerythritol tetramethacrylate.

8. The polymer of claim 1 and further comprising a free radical initiator comprising organic peroxides, diazocompounds, or a combination thereof.

9. The polymer of claim 8, wherein the free radical initiator is selected from the group consisting of benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide and azoisobutrylnitrile.

10. The polymer of claim 8, wherein the melt processable polymer comprises less than 0.25% by weight of the free radical initiator.

11. The polymer of claim 1 and further comprising an impact modifying additive selected from the group consisting of elastomeric copolyesters, polyaklylene glycols, malinated or epoxidized naturally occurring oils, and combinations thereof.

12. The polymer of claim 1, wherein the melt processable polymer comprises from about 20 to about 99 percent by weight of the hyper-branched polymer.

13. The polymer of claim 1, wherein the melt processable polymer comprises up to 10 percent by weight of the branching agent.

14. A method of producing a melt-processable hyper-branched polymer, the method comprising:

providing a biodegradable polymer comprising a linear polyester;

providing a branching agent comprising a multifunctional monomer capable of undergoing free radical hemolysis; and

processing the biodegradable polymer with the branching agent at temperatures resulting in free radical reactions between the biodegradable polymer and the branching agent to form the hyper branched polymer and wherein the hyper-branched polymer is capable of a subsequent melt processing process.

15. The method of claim 14, further comprising providing a free radical initiator along with the biodegradable polymer and the branching agent to initiate the free radical reactions between the biodegradable polymer and the branching agent to form the hyper branched polymer.

16. The method of claim 14, further comprising providing an impact modifying additive along with the biodegradable polymer and the branching agent wherein the impact modifying additive is selected from the group consisting of elastomeric copolyesters, polyaklylene glycols, malinated or epoxidized naturally occurring oils and combinations thereof.

17. The method of claim 14, wherein the biodegradable polymer comprises a linear biodegradable polymer.

18. A method of forming an article, the method comprising:

providing a feedstock produced by melt processing a biodegradable polymer comprising a linear polyester, a free radical initiator and a branching agent comprising a multifunctional monomer capable of undergoing free radical hemolysis, at a temperature resulting in free radical reactions between the biodegradable polymer and the branching agent to form a hyper-branched polymer; and

melt processing the hyper-branched polymer at a temperature between about 80°

C. and 300°

C. to form the article, wherein the article has a selected shape.

19. The method of claim 18 wherein processing comprises extruding, injection molding, blow molding, rotomolding or combinations thereof to form the article.

20. The method of claim 19, wherein the biodegradable polymer comprises a linear biodegradable polymer.