Disclosed are an optical film, including: a transparent film, and a coating layer on at least one surface of the transparent film, in which the coating layer is formed using a composition including a polymer resin, a dihydrazide-based crosslinking agent, and water-dispersible fine particles, and a polarizing plate including the same.

A method of reducing foamed density that results in a foamed polyvinyl chloride (PVC) component exhibiting reduced density. The foamed PVC component contains at least a PVC resin and a process aid blend. The process aid blend contains from 1 weight % to 60 weight % (based on the weight of the blend) of a functionalized process aid, and from 99 weight % to 40 weight % (based on the weight of the blend) of a non-functionalized process aid. The functionalized process aid includes at least one base polymer functionalized with a reactive epoxy, hydroxyl, -keto ester, -keto amide, or carboxylic acid functional group. The foamed PVC component containing the process aid blend has a lower density than a reference foamed PVC component made using the same process conditions and additives, but which contains only non-functionalized process aid and not the functionalized process aid.