Recyclate blends
Compositions comprising recyclate blends of polymer recyclate and polyester additives are described. In certain embodiments, the polyester additive is a PHA such as a poly-3-hydroxybutyrate-co-4-hydroxybutyrate copolymer having a weight percent 4-hydroxybutyrate of 8.5-45%. In other embodiments the PHA is mixed with the recyclate polymer at concentrations of 10-50% by weight of the recyclate blend. Methods of making the compositions of the invention are also described. The invention also includes articles made from the recyclate blends.
1. A composition, comprising:
a blend of a reprocessed or regrind polymer and a polyhydroxyalkanoate (PHA) additive,
wherein the PHA additive is a mixture of at least one poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer and a poly(3-hydroxybutyrate) homopolymer,
wherein the reprocessed or regrind polymer is a post-consumer recycled poly (vinyl chloride) (PVC), and
wherein the content of the PHA additive in the blend is from 10% to 20% by weight of the blend.
2. The composition of claim 1 , wherein the PHA additive has a biobased content of 85-100%.
3. The composition of claim 1 , wherein the at least one poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, a poly(3-hydroxybutyrate) homopolymer, or both have a percent crystallinity less than 35%.
4. The composition of claim 1 , wherein the at least one poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, a poly(3-hydroxybutyrate) homopolymer, or both have an average molecular weight range of about 250,000 to about 2.5 million g/mole.
5. The composition of claim 1 , wherein the at least one poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer has a content of 4-hydroxybutyrate (4HB) from 8% to 50% by weight of the copolymer.
6. The composition of claim 1 , wherein the composition has a biobased content of 8.5-46%.
7. The composition of claim 1 , further comprising one or more additional additives.
8. The composition of claim 7 , wherein the one or more additional additives are selected from plasticizers, peroxide initiators, clarifiers, nucleating agents, thermal stabilizers, oxidative stabilizers, inorganic fillers, anti-slip agents, compatibilizers, and blocking agents.
9. The composition of claim 7 , wherein the one or more additional additives are biobased.
10. The composition of claim 1 , wherein the blend has at least one improved material property selected from a tensile modulus, tensile stress at yield, tensile strain at yield, tensile stress at break, energy at break, and tear, compared to the reprocessed or regrind polymer alone.
11. The composition of claim 10 , wherein the improved material properties are tensile and tear properties.
12. The composition of claim 1 , wherein the post-consumer recycled PVC and the PHA additive are miscible.
13. The composition of claim 1 , wherein the composition is flexible, semi-rigid or rigid.
14. The composition of claim 1 , wherein the post-consumer recycled PVC was thermally processed and extruded.
15. A method of preparing a composition, comprising:
melt blending a reprocessed or regrind polymer and a polyhydroxyalkanoate (PHA) additive, wherein the PHA additive is a mixture of a poly(3-hydroxybutyrate) and at least one poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, using a single or twin screw extruder, two-roll mill, or Banbury mixer, thereby producing a blend;
wherein the content of the PHA additive in the blend is from 10% to 20% by weight of the blend,
wherein the reprocessed or regrind polymer is a post-consumer recycled poly(vinyl chloride) (PVC) that was thermally processed and extruded.