The present invention relates to improvements in a masterbatch which is a compounded concentrated mixture of colorants and/or additives to effect the properties, typically the color, of a target polymer. One aspect of the present invention comprises a polyvinyl chloride (PVC) masterbatch comprising a chlorinated polyolefin having a melt flow index (MFI) characteristic of between 1 and 30 having units of g/10 min at a temperature of 180° C. at a weight of 10 kg; an acrylic processing aid and/or acrylic impact modifier and/or acrylic moulding powder; and at least one dye, pigment and/or functional additive.