Functionalized process aid blends for cellular PVC

A method of making a foamed polyvinyl chloride (PVC) component, wherein the method comprises:

• combining:
• a) a polyvinyl chloride (PVC) resin,
• b) a process aid blend, wherein the process aid blend comprises from about 1% by weight to about 20% by weight of a functionalized process aid and from about 99% by weight to about 80% by weight of a non-functionalized process aid based on 100% by weight of the process aid blend;
• and
• c) a blowing agent;
• to form a foamable PVC composition;
• and
• processing the foamable PVC composition to form the foamed PVC component;
• wherein the functionalized process aid comprises at least one base polymer which is functionalized with from 0.1 wt. % to 35 wt. % of a reactive epoxy, hydroxyl, β-keto ester, β-keto amide, or carboxylic acid functional group, or mixture thereof based on a total weight of the functionalized process aid;
• and
• wherein the foamed PVC component comprising the process aid blend has a lower density than a reference foamed PVC component comprising a 100% non-functionalized process aid, and wherein the foamed PVC component comprising the process aid blend and the reference foamed PVC component comprising the 100% non-functionalized process aid are made using the same process conditions and additives;
• and
• wherein the process aid blend is present in an amount from 0.1 to 15 parts per hundred (phr) by weight of the PVC resin.