Durable polyhydroxyalkanoate compositions

Abstract

A polyhydroxyalkanoate composition, having a an elongation at break (ASTM D648) greater than 3%, an impact resistance (IS0179 1 eA, 23° C., unnotched) greater than 18 KJ/m2 and a flexural modulus of at least 950 MPa, includes at least 25% wt of a polyhydroxyalkanoate component (I); from 5 to 40% wt of one or more thermoplastic polymers as a non-polyhydroxyalkanoate component (II); from 0 to 40% wt of one or more fillers (III); from 0 to 20% wt of one or more plasticizers (IV); and from 0 to 10% wt of one or more additives (V). The polyhydroxyalkanoate composition can be used for the preparation of durable goods that may be labelled as containing more than 20% non-fossil carbon, and for articles prepared therefrom.

1 . A polyhydroxyalkanoate composition comprising:
 at least 25% wt of a polyhydroxyalkanoate component (I), comprising one or more hydroxyalkanoate copolymers wherein the content of poly(3-hydroxybutyrate) homopolymer is and less than 5% wt;   from 5 to 40% wt of one or more thermoplastic polymers as a non-polyhydroxyalkanoate component (II) selected from the group consisting of (IIa) a thermoplastic polyurethane which is a block copolymer, and has a hardness lower than 56 Shore D, as measured according to ASTM D2240; a mixture of a thermoplastic polyurethane (IIa) and (IIb) an acrylic polymer; an acrylic block copolymer (IIb1) with a core that is butadiene based and/or acrylic based rubber and that is crosslinked; an acrylic terpolymer (IIb2) containing glycidyl and/or maleic groups; and mixtures thereof,   comprising no more than 5% wt biodegradable polymers (ASTM D6400);   from 0 to 40% wt of one or more fillers (III);   from 0 to 20% wt of one or more plasticizers (IV); and   from 0 to 10% wt of one or more additives (V),   wherein component (I) and (II) together comprise at least 40% wt of the composition, and   the % wt of the components is calculated on the total weight of components (I) to (V) of the composition and adds up to 100% wt.   
     
     
         2 . The polyhydroxyalkanoate as claimed in  claim 1 , having an elongation at break (ASTM D638) greater than 3%, an impact resistance (Charpy test; ISO179 1 eU, 23° C., unnotched) greater than 18 KJ/m 2  and a flexural modulus of at least 950 MPa. 
     
     
         3 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein the polyhydroxyalkanoate component (I) comprises one or more copolymers of a 3-hydroxyalkanoate. 
     
     
         4 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein the polyhydroxyalkanoate component (I) comprises one or more copolymers of 3-hydroxybutyrate and a 3-hydroxyalkanoate with more than 4 carbon atoms; and/or one or more copolymers of 3-hydroxybutyrate and a 4-hydroxyalkanoate with 4 or more carbon atoms; and/or a terpolymer of 3-hydroxybutyrate and two or more hydroxyalkanoates, preferably a copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate p(3HB-co-4HB), a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate p(3HB-co-3HV), or a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate p(3HB-co-3HH) or a copolymer of 3-hydroxybutyrate and 3-hydroxyoctanoate p(3HB-co-3HO). 
     
     
         5 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein component (II) is a mixture of
 (IIa) a thermoplastic polyurethane; and   (IIb) an acrylic polymer, wherein (IIb) is (IIb1) a block copolymer with a core that is butadiene based and/or acrylic based rubber and that is crosslinked; and/or   (IIb2) a terpolymer containing glycidyl and/or maleic groups.   
     
     
         6 . The polyhydroxyalkanoate composition as claimed in  claim 5 , wherein the thermoplastic polyurethane (IIa) is a block copolymer, preferably having a Melting Point (measured according to ASTM3418) lower than 180° C. and/or a glass transition temperature Tg lower than 40° C. (measured according to ISO 11357) and/or a hardness lower than 56 Shore d (measured according to ASTM D2240). 
     
     
         7 . The polyhydroxyalkanoate composition as claimed in  claim 6 , wherein the thermoplastic polyurethane (IIa) is based on a saturated polyester, preferably based on adipic acid, reacted with an aromatic isocyanate with two or more isocyanate groups, preferably 4,4′-methylenediphenyl diisocyanate (MDI). 
     
     
         8 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein the acrylic polymer (IIb), (IIb1) and/or (IIb2) has a value of Melt flow Index (ASTM D1238, 175° C./2.16 kg) higher than 0.25 g/10 min and/or a glass transition temperature, Tg, lower than 100° C. 
     
     
         9 . The polyhydroxyalkanoate composition as claimed in  claim 8 , wherein the acrylic polymer (IIb) is a crosslinked butadiene acrylonitrile elastomer, and/or a crosslinked acrylate terpolymer. 
     
     
         10 . The polyhydroxyalkanoate composition as claimed in  claim 8 , wherein the acrylic polymer (IIb) is a crosslinked styrene-acrylate elastomer. 
     
     
         11 . The polyhydroxyalkanoate composition as claimed in  claim 8 , wherein the acrylic polymer (IIb) is a terpolymer of ethylene, an alkyl acrylate or methacrylate, and glycidyl methacrylate or glycidyl acrylate. 
     
     
         12 . The polyhydroxyalkanoate composition as claimed in  claim 1  wherein a combination of a TPU (IIa) and an acrylic polymer (IIb) is used in relative weight amounts of 3:1 to 1:3, preferably 2:1 to 1:2. 
     
     
         13 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein the component (II) or combination of components (II) is used in an amount of 10 to 35% wt. 
     
     
         14 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein component (III) is selected from mineral fillers, synthetic fillers or mixtures thereof, preferably mineral fillers selected from talc, carbonates, silicates (more preferably clays and zeolites), and/or metal oxides (more preferably titanium oxide, zinc oxide, magnesium oxide). 
     
     
         15 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein component (IV) is an epoxidized oil, preferably an epoxidized oil of a vegetable source, more preferably epoxidized soybean oil. 
     
     
         16 . The polyhydroxyalkanoate composition as claimed in  claim 1 , wherein component (V) is selected from one or more from the group of additives comprising antioxidants, anti-hydrolysis agents, UV stabilizing agents, pigments and surface modification agents. 
     
     
         17 . Use of the composition according to  claim 1 , for the preparation of durable goods that may be labelled as containing more than 20, preferably more than 40. % wt non-fossil carbon. 
     
     
         18 . Articles prepared from a polyhydroxyalkanoate composition as claimed in  claim 1 .