Abstract: A method for feeding a boron compound, which comprises feeding at least one boron compound selected from (1) to (3) described below in the state suspended or slurried in a solvent continuously to a reactor; a boron compound in the form of fine particles being one or more boron compounds selected from (1) to (3) described below and having a maximum particle diameter of 50 &mgr;m or less; a catalyst component for olefin polymerization consisting of said boron compound in the form of fine particles; a method for producing a boron compound in the form of fine particles which comprises dissolving one or more boron compounds selected from (1) to (3) described below in an aromatic hydrocarbon solvent and then precipitating in an aliphatic hydrocarbon solvent; and a method for producing a boron compound in the form of fine particles which comprises pulverizing one or more boron compounds selected from (1) to (3) described below so that their maximum particle diameter is 50 &mgr;m or less.

Abstract: The present invention provides a polypropylene-based resin composition which is light weighing, has a very high values of stiffness and heat resistance, exhibits superior scratchproof property and is superior in the processibility with better flowability upon molding thereof, especially that can favorably be used for injection molding. The polypropylene-based resin composition according to the present invention is constituted predominantly of polypropylene and has the following characteristic features A and B: A: a melt flow rate (MFR), determined at 230° C. under a load of 2.16 kg, in the range of 5-50 g/10 min. and B: a content of a high molecular weight polypropylene having an intrinsic viscosity [&eegr;] of 9-13 dl/g in the range of 15-30% by weight.