Abstract: A polyolefin plastic composition having improved transparency and reduced molding shrinkage, which consists essentially of at least one polymer or copolymer of an aliphatic monoolefin and dibenzylidene sorbitol, the proportion of the dibenzylidene sorbitol being 0.1 to 0.7% by weight based on the total weight of the composition.

Abstract: A process for fire-proofing treatment of shaped articles of aromatic polyamides which comprises contacting a shaped article of an aromatic polyamide with an aqueous solution of a phosphorus-containing inorganic compound free from halogen and sulfur, drying it and then post heat-treating it; characterized in that said shaped article is contacted with an aqueous solution of a treating compound selected from the group consisting of halogen- and sulfur-free, phosphorus-containing inorganic acids and their ammonium, amine and urea salts in a concentration of about 2 to about 30% by weight, dried at a temperature of not more than about 150.degree. C., and then post heat-treated at a temperature of about 300.degree. C. to about 450.degree. C.

Abstract: A filter medium which permits an increased amount of filtration. The filter medium can be prepared by blending 100 parts by weight of aggregate particles, 5-18 parts by weight of an inorganic bonding material having a chemical composition of about 10-50% by weight of SiO.sub.2 and about 5-20% by weight of B.sub.2 O.sub.3 and containing at least 70% by weight of a non-vitreous substance such as talc or boric acid, and about 3-15 parts by weight of a combustible substance such as wheat flour, kneading the mixture with a caking material and water, molding the kneaded mixture, drying it, and then calcining the dried mixture at a temperature not lower than about 1100.degree.C. The size and number of the air-permeable pores in the filter medium can be controlled by adjusting the amounts of the bonding material and combustible substance.