Abstract: A resin composition comprising a polypropylene resin, a polyphenylene ether resin and a compatibility agent wherein dispersion particles comprising the polyphenylene ether resin (b) are dispersed in a matrix comprising the polypropylene resin (a), a minor diameter of the dispersion particles is 2 .mu.m or less, and the ratio of major diameter/minor diameter is 1-10.

Abstract: A resin composition having nice color tone and high crack-resistance as well as flame-retardancy is obtained by blending(A) 100 weight parts of a resin composition containing a rubber-reinforced vinyl aromatic polymer and polyphenylene ether represented by the following general formula: ##STR1## wherein each of R.sub.1 and R.sub.2 represents a monovalent residue such as the same or different alkyl group having 1-4 carbon atoms, aryl group, halogen and hydrogen, and n represents the polymerization degree or a polyphenylene ether onto which a vinyl aromatic compound is graft-copolymerized, in which the polyphenylene ether content is 5-70 wt. % (based on the weight of the resin part),(B) 1-30 weight parts of a halogenated aromatic compound and(C) 0.5-20 weight parts of a non-crystalline ethylene-propylene copolymer.

Abstract: A novel diester compound of the formula (I): ##STR1## wherein each of R.sub.1 and R.sub.2 represents a group of the formula (II): ##STR2## wherein m is an integer of 1 to 5, is found to be capable of imparting excellent flame-retardancy to various inflammable polymeric materials such as polystyrene, polyester, polyamide, polyphenylene oxide, etc. without deleterious effects on other physical properties of such polymeric materials.

Abstract: A novel diester compound of the formula (I): ##STR1## wherein each of R.sub.1 and R.sub.2 represents a group of the formula (II): ##STR2## wherein n is an integer of 0 to 4; and m an integer of 1 to 5, is found to be capable of imparting excellent flame-retardancy to various inflammable polymeric materials such as polystyrene, polyester, polyamide, polyphenylene oxide, etc. without deleterious effects on other physical properties of such polymeric materials.