Abstract: An automobile part comprising a polypropylene resin composition, the polypropylene resin composition comprising a propylene homopolymer (A1), an elastomer (B) and an inorganic filler (C) in specified proportions. The polypropylene homopolymer (A1) exhibits an MFR (230° C.) of 20 to 300 g/10 min, a ratio of position irregular units derived from 2,1-insertion or 1,3-insertion of propylene monomer relative to all propylene structural units, determined from a 13C-NMR spectrum, each of 0.05% or less, and an Mw/Mn, determined by GPC, of 1 to 3.

Abstract: An in-mold coating molded article is obtained by coating the surface of a resin molded product comprising a hydroxyl group-containing polypropylene resin composition (A) with a paint composition for in-mold coating, wherein the composition (A) comprises a polypropylene resin (i), an additive rubber (ii) and optionally a polymer compound (iii) other than the polypropylene resin (i) and the additive rubber (ii), the total hydroxyl value of the polypropylene resin (i), the additive rubber (ii) and the optional polymer compound (iii) is from 1 to 40, the composition (A) has a rubber component content (total of the amount of the additive rubber (ii) and the amount of components soluble in n-decane at 23° C.

Abstract: An automobile part comprising a polypropylene resin composition, the polypropylene resin composition comprising a propylene homopolymer (A1), an elastomer (B) and an inorganic filler (C) in specified proportions. The polypropylene homopolymer (A1) exhibits an MFR (230° C.) of 20 to 300 g/10 min, a ratio of position irregular units derived from 2,1-insertion or 1,3-insertion of propylene monomer relative to all propylene structural units, determined from a 13C-NMR spectrum, each of 0.05% or less, and an Mw/Mn, determined by GPC, of 1 to 3.

Abstract: An automobile part comprising a polypropylene resin composition, the polypropylene resin composition comprising a propylene homopolymer (A1), an elastomer (B) and an inorganic filler (C), or comprising a propylene block copolymer (A2) and an inorganic filler (C) optionally together with an elastomer (B), in specified proportions. The propylene homopolymer (A1), or the propylene homopolymer segment of the propylene block copolymer (A2) exhibits an MFR (230-C) of 20 to 300 g/10 min, a ratio of position irregular units derived from 2,1-insertion or 1,3-insertion of propylene monomer relative to all propylene structural units, determined from a 13C-NMR spectrum, each of 0.2% or less, and an Mw/Mn, determined by GPC, of 1 to 3.

Abstract: An in-mold coating molded article is obtained by coating the surface of a resin molded product comprising a hydroxyl group-containing polypropylene resin composition (A) with a paint composition for in-mold coating, wherein the composition (A) comprises a polypropylene resin (i), an additive rubber (ii) and optionally a polymer compound (iii) other than the polypropylene resin (i) and the additive rubber (ii), the total hydroxyl value of the polypropylene resin (i), the additive rubber (ii) and the optional polymer compound (iii) is from 1 to 40, the composition (A) has a rubber component content (total of the amount of the additive rubber (ii) and the amount of components soluble in n-decane at 23° C.

Abstract: An automobile part comprising a polypropylene resin composition, the polypropylene resin composition comprising a propylene homopolymer (A1), an elastomer (B) and an inorganic filler (C), or comprising a propylene block copolymer (A2) and an inorganic filler (C) optionally together with an elastomer (B), in specified proportions. The propylene homopolymer (A1), or the propylene homopolymer segment of the propylene block copolymer (A2) exhibits an MFR (230° C.) of 20 to 300 g/10 min, a ratio of position irregular units derived from 2,1-insertion or 1,3-insertion of propylene monomer relative to all propylene structural units, determined from a 13C-NMR spectrum, each of 0.2% or less, and an Mw/Mn, determined by GPC, of 1 to 3.

Abstract: There are provided an optical disk substrate formatted according to the zone formatted system, method for initialization thereof, and driving apparatus for initialization of the optical disk. The optical disk substrate is initialized while at least one track in the vicinity of the inner peripheral side and/or the outer peripheral side in the radial direction of the boundary between an optional zone and another zone situated on the outer peripheral side is left unused as a recording area. By virtue of this construction, at least one of the tracks having a high possibility of bringing about the pit shift or double transfer is left unused as a recording area. Accordingly, the information stored in a recording area can be read out without being influenced by the occurrence of the pit shift or double transfer, and thus it is possible to get rid of the occurrence of a burst error caused by such pit shift or double transfer.

Abstract: Information recording discs comprise a disc substrate having a recording layer on one side thereof, one hub having an insertion portion to be inserted into a center hole of the disc substrate and a flange portion to cover the disc substrate in the vicinity of the center hole, at least an apex of the insertion portion being composed of a magnetic material, the hub being inserted into the center hole so that the flange portion is positioned on the recording layer side of the disc substrate, and an adhesive layer is provided between the flange portion and the disc substrate. By this construction, a portion of the hub which protrudes from the back surface of the disc substrate, facing toward the spindle of a turn table can be altered in dimension and/or the diameter of the protrusion portion of the hub can be made smaller than that of the center hole of the disc substrate.

Abstract: Information recording discs comprise a disc substrate having a recording layer on one side thereof, one hub having an insertion portion to be inserted into a center hole of the disc substrate and a flange portion to cover the disc substrate in the vicinity of the center hole, at least an apex of the insertion portion being composed of a magnetic material, the hub being inserted into the center hole so that the flange portion is positioned on the recording layer side of the disc substrate, and an adhesive layer is provided between the flange portion and the disc substrate. By this construction, a portion of the hub which protrudes from the back surface of the disc substrate, facing toward the spindle of a turn table can be altered in dimension and/or the diameter of the protrusion portion of the hub can be made smaller than that of the center hole of the disc substrate.

Abstract: An information recording disc including a plurality of disc substrates (2), at least one of which has a recording medium containing layer (1), two pieces of hubs mounted over the center hole of said disc substrates on both sides thereof, each hub having a portion to be inserted into said center hole and a flange portion to cover a portion of said disc substrate in the vicinity of said center hole, and an adhesive layer (13, 14) formed between said hubs and said disc substrates and between said two hubs. An adhesive layer (7) laminates the substrates (2a, 2b) to one another.

Abstract: The optical recording media disclosed herein comprises a substrate and a recording layer formed thereon, wherein the recording layer is irradiated with beam of energy to form thereon bits corresponding to given pieces of information and thereby record the pieces of information. The recording layer comprising Te, Cr, C and H, the proportion of Cr contained in said recording layer, based on all atoms constituting the recording layer, is 0.1-40 atom % and that of C contained in said recording layer is 0.1-40 atom %. In another aspect, the proportion of Cr contained in said recording layer, based on the sum total of Te and Cr atoms present in said recording layer, is 0.1-60 atom %, and the proportion, based on the sum total of Te, Cr and C atoms present in said recording layer, of C is 0.1-40 atom %.

Abstract: Optical recording media disclosed herein are excellent in recording sensitivity as well as in the adhesion of the substrate to the recording layer, said substrate consisting of a random copolymer of ethylene and a cycloolefin and having a specific structure.

Abstract: The optical recording media disclosed herein comprises a substrate and a recording layer formed thereon, wherein the recording layer is irradiated with beam of energy to form thereon bits corresponding to given pieces of information and thereby record the pieces of information. The recording layer comprises Te, Cr, C and H, the proportion of Cr contained in said recording layer, based on all atoms constituting the recording layer, is 0.1-40 atom % and that of C contained in said recording layer is 0.1-40 atom %. In another aspect, the proportion of Cr contained in said recording layer, based on the sum total of Te and Cr atoms present in said recording layer, is 0.1-60 atom %, and the proportion, based on the sum total of Te, Cr and C atoms present in said recording layer, of C is 0.1-40 atom %.

Abstract: A process for producing a magnetic hub for an optical disc which is fixed to the spindle of a disc drive by means of a magnetic clamp system, which process comprises positioning and setting an annular metal plate composed of a ferromagnetic substance having burrs on one side thereof produced by punching in a mold and then injecting a resin into the mold.

Abstract: Optical recording media disclosed herein are excellent in recording sensitivity as well as in the adhesion of the substrate to the recording layer, said substrate consisting of a random copolymer of ethylene and a cycloolefin and having a specific structure.

Abstract: A resin composition for spacers of an information recording disc which comprises: (A) a random copolymer of ethylene and at least one cycloolefin having an intrinsic viscosity [.eta.] of from 0.05 to 10 dl/g, as measured in decalin at a temperature of 135.degree. C., and (B) from 0.01 to 5 parts by weight, based on 100 parts by weight, of said copolymer A, of an inorganic particles such as titania and silica having a particle size of not more than 300 .mu.m. Spacers made of the composition described herein can be welded to disc substrates within a shortened period of ultrasonic vibration to produce an information recording disc having a reduced warp angle.

Abstract: A process for producing an information recording disc of an air sandwich structure by ultrasonic welding two disc substrates, at least one of which has a recording medium containing layer, to each other through outer and inner peripheral spacers lying therebetween, which process is characterized in that the outer peripheral spacer is first welded to the disc substrate on one side, the disc substrate on the other side is then superposed through the inner peripheral spacer on said outer peripheral spacer-welded disc substrate turned inside out, and said outer peripheral spacer and disc substrate on the other side, and said inner peripheral spacer and disc substrates on both sides are ultrasonic welded together simultaneously.