Abstract: A propylene resin composition composed of a nucleating agent and a propylene resin having a melt index (MI) of not greater than 1.2 g/10 min and satisfying a relationship between elongational viscosity (.eta..sub..EPSILON.) and melt index (MI) represented by2.0.times.10.sup.5 .times.MI.sup.-0.68 .gtoreq..eta..sub..EPSILON. .gtoreq.1.5.times.10.sup.5 MI .times.MI.sup.-0.68.The composition is endowed with high-rigidity, has excellent drawdown resistance, ensures practical discharge rate during blow-molding at low resin temperature of 220.degree. C. or less, and enables high-productivity production of large-sized blow-molded parts featuring light weight, excellent rigidity, dimensional stability, and heat resistance. Blow-molding of the propylene resin composition provides a blow-molded article which is advantageously used as, particularly, a large-sized automobile part, such as a bumper, a bumper beam, a seat back, an instrument panel, or a like part.

Abstract: A propylene resin composition containing a phenolic antioxidant, and a phosphorus-containing antioxidant which has a differential melt index (.DELTA.MI) calculated from a melt index (MIi) as measured at a propylene temperature of 230.degree. C. and under a load of 2,160 g and a melt index (MIe) as measured at a propylene temperature of 230.degree. C. and under a load of 2,160 g after five repetitions of a 100% recycle test is not greater than 0.5 g/10 min, and MIe is not greater than 1.2 g/10 min. This propylene resin composition enables manufacture of large-sized blow-molded articles featuring light weight, excellent rigidity, dimensional stability, heat resistance and showing good drawdown resistance, suitable for continuous blow molding. Blow moldings are advantageously used as automobile bumpers, bumper beams, or like parts.

Abstract: A diamond-coated body is prepared by coating a diamond film on the surface of a sintered body by means of vapor phase synthesis, the sintered body being so prepared by subjecting a sintered body prepared from ceramics based on silicon nitride to heat treatment at the temperature of 1,400.degree. C. to 1,700.degree. C. as to give a crystalline intergranular phase. The resulting diamond-coated body has excellent adhesion between the diamond film and the substrate and it is appropriately employed for cutting tools and so on because, when applied to the cutting tools, they can be used for cutting for a long period of time.

Abstract: The present invention is directed to a diamond-coated body having a diamond coat film formed on the surface of a ceramic substrate containing acicular grains having a thickness of 0.2 .mu.m to 1 .mu.m and an aspect ratio of 2 or higher at the two-dimensional density of 30% or higher, and the diamond coat film has good adhesion to the ceramic substrate. Thus the diamond-coated body is superior in durability and can be appropriately utilized as cutting tools and so on.

Abstract: The present invention relates to a diamond-coated member characterized by superposing an acicular diamond layer, an intermediate layer formed by a metal belonging to either of the group IIIb, IVa, Va or VIa of the periodic table or by a compound containing the said metal, Si or B, and a non-acicular diamond layer on the surface of a base material and to a process for the preparation of a diamond-coated member characterized in that a diamond layer is formed on the surface of a base material by vapor phase synthesis method; the resulting diamond layer is converted into acicular diamond by exposing the resulting diamond layer to a gas obtainable by exciting an oxygen-containing etching gas; an intermediate layer comprising a metal belonging to either of the group IIIb, IVa, Va or VIa of the periodic table or by a compound containing the said metal, Si or B is formed on the resulting acicular diamond; and the resulting intermediate layer is exposed to a gas obtainable by exciting a raw material gas containing a c