More often, the one or more degradants are added to virgin polymer by master batching. Master batching involves adding a package that includes the degradants in the form of a master batch to the virgin polymer. A master batch is a blend of the polymer containing high concentrations of the degradants. The master batch is prepared by the process described above except that higher concentrations of degradants are added to the virgin polymer. Typically a master batch contains between about 5 to 20 percent of the degradants by weight of the polymer and may contain as much as 30 percent of the degradants by weight of the polymer. Polymer compositions for final use, having the desired lower concentration of degradants, are then prepared by combining remelted virgin polymer and remelted polymer from the master batch in a ratio so as to provide a desired final concentration. Typically the weight ratio of virgin polymer to master batch is about 5:1. An extruder, such as a twin screw extruder, is typically used to mix the two polymer compositions and to disperse the master batch degradants throughout the virgin polymer. The resultant mixture is then extruded into pellets or other useable form of the polymer for use in latter manufacturing operations such as, extrusion, film blowing, or molding to produce a final article.

The process used to make the master batch, however, involves melting the polymer to add the degradants and, thus, includes all the disadvantages discussed above that are associated with remelting a polymer to add a degradant. Moreover, combining a master batch with a virgin polymer has numerous other disadvantages. For example, it is difficult to homogeneously distribute the degradant throughout the final polymer mix, since it is difficult to thoroughly mix two polymer melts. Furthermore, master batches are inconvenient to use since, due to the high concentrations of degradants, they are susceptible to decomposition and therefore can only be stored for a limited length of time. Thus, they must often be ordered and shipped immediately prior to use. Furthermore, the high concentrations of degradants present in the master batch typically leads to deterioration of the polymer in the master batch and, thus, results in a final polymer that is of inferior quality. This is especially true when the polymer is subjected to the high temperatures necessary for extrusion or film blowing.

The difficulty in obtaining a polymer of high quality and the high costs associated with preparing polymers containing degradants has been a barrier to these biodegradable finished and semi-finished products becoming commercially available. Thus, there is a need for improved methods of integrated turn key solutions that are more cost effective and that produce a higher quality product that is really totally biodegradable.