Masterbatch of highly loaded amorphous PHA dispersed in amorphous or semi-crystalline polymer and method of producing the same
An amorphous or semi-crystalline polymer/aPHA composition (masterbatch) has a high load of aPHA (30 to 50 wt % based on the total amount of the composition). A method for production of the composition includes two or more split feedings of the aPHA in a blending or mixing or compounding operation. The method includes feeding about 1-15 weight percent (wt %) of the total aPHA in a primary feed hopper of a blending or mixing or compounding apparatus and about 30-49 weight percent downstream in the process.
1 . A pelletized masterbatch composition comprising continuous amorphous or semi-crystalline polymer and discrete amorphous polyhydroxyalkanoate (aPHA) dispersed in the continuous amorphous or semi-crystalline polymer, wherein the aPHA is contained in an amount of about 30 to 50 wt % based on a total weight of the pelletized masterbatch composition, wherein the pelletized masterbatch is produced by a method comprising:
feeding the amorphous or semi-crystalline polymer and about 1-15 wt %, based on a sum of total aPHA and total amorphous or semi-crystalline polymer in the masterbatch, of aPHA to a primary feed;
melting the primary feed;
feeding about 30-49 wt %, based on the sum of the total aPHA and the total amorphous or semi-crystalline polymer in the masterbatch, of aPHA to a secondary feed that is physically separated from the primary feed to combine the secondary feed and the melted primary feed, and
dispersing aPHA of the secondary feed in the melted primary feed to obtain a masterbatch melt, and cooling and pelletizing the masterbatch to obtain the pelletized mastertabch in which discrete aPHA particles are dispersed in the amorphous or semi-crystalline polymer, and
wherein the amorphous or semi-crystalline polymer is selected from the group consisting of polylactic acid (PLA), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), polyethylene-succinate (PES), polycaprolactone (PCL), semi-crystalline polyhydroxyalkanoate (PHA), and a combination thereof, and
wherein the discrete aPHA particles have an average diameter of less than 3 μm.
2 . The pelletized masterbatch composition according to claim 1 , comprising 40 wt % or greater and less than 50 wt % of aPHA based on the total weight of the pelletized masterbatch composition.
3 . The pelletized masterbatch according to claim 1 , wherein the aPHA comprises a poly 3-hydroxybutyrate (P3HB) copolymer.
4 . The pelletized masterbatch according to claim 1 , wherein the aPHA is an aPHA copolymer comprising about 50%-80% by weight of 3-hydroxybutyrate monomer units and about 20%-50% by weight of one or more of the hydroxyalkanoate monomer units selected from the group consisting of 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, 3-hydroxydodecanoate and 4-hydroxybutyrate.
5 . A method of preparing an amorphous or semi-crystalline polymer product comprising adding the amorphous or semi-crystalline polymer/amorphous polyhydroxyalkanoate (aPHA) masterbatch composition according to claim 1 into the amorphous or semi-crystalline polymer to obtain a mixture and subjecting the mixture to injection molding, extrusion, thermoforming, blow molding, or compression molding.