A method for providing long term stability for an alkaline-sensitive biocide in a poly-propylene product by incorporating the biocide, for example Deltamethrin, together with an acid in a polymer matrix with polypropylene.一種用以提供聚丙烯產品中之鹼敏感性殺生物劑長期安定性之方法,其藉由令殺生物劑(例如第滅寧)與酸在具有聚丙烯的聚合物基質中摻合而達成。