Abstract: A process for producing a plastic pipe having an oval cross-sectional shape with a high dimensional precision, which comprises conducting a roughly shaped plastic pipe having an oval cross-sectional shape, which is in the softened state and composed of a large-diameter portion, a small-diameter portion and transitional portions connecting them to each other, to a cooling tank while its shape is adjusted by being passed through a forming tube with its large-diameter portion down; cooling the form-adjusted plastic pipe in the cooling tank by dipping the large-diameter portion or both the large diameter portion and a part of the transitional portions contiguous thereto in a cooling bath; and subjecting that portion of the form-adjusted plastic pipe which is out of the cooling bath to a shower of a cooling liquid. This plastic pipe is useful for a drainage or sewage system.

Abstract: A stabilizer for chlorine-containing resins, comprising calcium hydroxide coated with a calcium salt of an organic acid, and a process for producing the same wherein calcium hydroxide and an organic acid are reacted at a molar ratio of 1 mole of calcium hydroxide: not more than 2 moles of organic acid in the presence of a medium and a surface active agent, while heating and stirring, to convert the outer surface of the calcium hydroxide to a calcium salt of the organic acid.