Abstract: This invention provides a packaging material for a photographic photosensitive material having a conductive light-shielding thermoplastic resin film layer which comprises a resin composition comprising 3 to 49 wt. % of a thermoplastic elastomer having a crystallinity of 40% or less measured by the X-ray diffraction method, 0.01 to 10 wt. % of lubricant, and 1 to 70 wt. % of carbon black which is acetylene carbon black or furnace carbon black, which is excellent in the dispersion of carbon black to improve light-shielding ability and rare generation of lumps and microgrits, heat sealing properties, small degradation of physical strength, film moldability, etc.

Abstract: An abrasive member for a very high return loss optical connector ferrule is used in abrading an end of an optical connector ferrule having a ferrule hole, in which an optical fiber has been inserted and secured, into a convex spherical surface. The abrasive member comprises a flexible substrate and an abrasive layer, which is formed on the surface of the flexible substrate and comprises a binder and abrasive grains. The surface roughness Ra, expressed in terms of arithmetic mean deviation, of the abrasive layer falls within the range of 0.01 .mu.m to 0.05 .mu.m. The abrasive member carries out polishing such that the surface smoothness of the ferrule surface and the optical fiber surface may be kept high, such that a difference in level between the ferrule surface and the optical fiber surface may not occur, and such that the very high return loss characteristics may thereby be obtained.

Abstract: An abrasive member comprises a substrate and an abrasive layer, which is constituted of a binder and abrasive grains dispersed therein, wherein the abrasive grains are constituted of sintered .alpha.-alumina grains. The abrasive member is capable of abrading a material to be abraded such that no abnormal abrasion scratch may occur on the abraded material.

Abstract: An abrasive tape having an abrasive layer primarily containing abrasive grains and a binder and formed on a flexible substrate and a member to be cleaned are fed in substantially opposite directions with the abrasive layer and a surface of the member kept in contact with each other with the ratio of the feed rate of the member to the feed rate of the abrasive tape kept not higher than 1/1.

Abstract: An abrasive member comprises a non-magnetic substrate and a plurality of abrasive layers, which are overlaid upon the non-magnetic substrate, each of the abrasive layers mainly containing a binder and hard abrasive grains, which have a Mohs hardness of at least 6 and are dispersed in the binder. The plurality of the abrasive layers include a top abrasive layer and a lower abrasive layer, which is formed between the non-magnetic substrate and the top abrasive layer. The thickness of the top abrasive layer is at most A/2, where A represents the thickness of the lower abrasive layer. The mean grain diameter of the abrasive grains contained in the top abrasive layer is at most B/2, where B represents the mean grain diameter of the abrasive grains contained in the lower abrasive layer.

Abstract: An abrasive tape is disclosed, comprising a flexible support having thereon an abrasive layer containing mainly an abrasive particle and a binder resin, wherein said abrasive layer has a thickness of from 0.3 to 10.0 .mu.m, an interlayer is provided between said abrasive layer and said flexible support, the thickness of said interlayer is 1 .mu.m or more, 30% or more of the thickness of said flexible support and larger than the thickness of said abrasive layer, and said interlayer has a Young's modulus of from 10 to 150 Kg/mm.sup.2. The abrasive tape may be used for cleaning and polishing a magnetic head.

Abstract: An abrasive tape comprises a substrate and an abrasive layer, which is overlaid on the substrate and is constituted of fine abrasive grains and a binder, wherein the abrasive layer contains an alkyl sulfosuccinic acid salt ester. The abrasive tape gives little scratching and little chipping to materials to be abraded and has a sufficiently high abrasive powder.

Abstract: An abrasive tape comprises a flexible substrate and an abrasive layer, which is overlaid on the flexible substrate and which primarily contains fine abrasive grains and a binder resin. The thickness of the flexible substrate falls within the range of 3 .mu.m to 10 .mu.m. The fine abrasive grains of the abrasive layer may contain at least one kind of grains, which have a mean grain diameter falling within the range of 0.05 .mu.m to 20 .mu.m and which are selected from the group consisting of chromium oxide grains, .alpha.-alumina grains, silicon carbide grains, non-magnetic iron oxide grains, and diamond grains.

Abstract: A surface of a member having intrinsic projections thereon is polished to remove the intrinsic projections. An abrasive tape is formed of a substrate and an abrasive layer formed thereon. The abrasive layer primarily contains abrasive grains and a binder. The abrasive tape and the member are slid in substantially opposite directions with the abrasive layer and the surface of the member kept in contact with each other.

Abstract: An abrasive tape for polishing a magnetic head includes a substrate and an abrasive layer which is formed on the substrate. The abrasive layer is composed of abrasive grains and a binder having an acidic functional group. The abrasive layer contains basic carbon black having a pH within the range of 7 to 10 and a mean grain size of 0.01 to 0.1 .mu.m.

Abstract: A manufacturing method, for an abrasive tape used for the burnishing of items such as floppy disks, which significantly reduces resulting scratches. An abrasive tape is manufactured by the steps of applying a coating liquid which contains as a major composition abrasive particles and a binder resin to a flexible substrate; drying the flexible substrate to produce an abrasive layer; and subjecting the abrasive layer to a surface smoothing treatment in order to align the tip ends of the abrasive particles to a uniform position by passing the abrasive layer between pressure rollers in such a manner that the flexible substrate comes in contact with an elastic roller, whereas the abrasive layer comes in contact with a metal roller, and wherein the pressure rollers are composed of the elastic roller having a hardness of 50-80 measured by a spring type hardness tester A and the metal roller, and are arranged opposite to each other.

Abstract: A method of preparing a magnetic coating composition comprises a first process for kneading ferromagnetic grains, a binder and a binder solution Y1 by use of a two-shaft continuous kneading and mixing machine to obtain a kneaded mixture K1 having a solid content within the range of 65 wt % to 95 wt %, a second process for kneading a binder solution Y2 and the kneaded mixture K1 by use of the two-shaft continuous kneading and mixing machine to obtain a primary diluted mixture K2 having a solid content within the range of 50 wt % to 70 wt %, a third process for diluting and dispersing the primary diluted mixture K2 in an organic solvent to obtain a secondary diluted mixture K3 having a solid content within the range of 25 wt % to 50 wt %, and a fourth process for finely dispersing the secondary diluted mixture K3 to obtain a dispersion mixture K4 having a solid content within the range of 25 wt % to 45 wt %.

Abstract: An abrasive tape comprises a flexible substrate and an abrasive layer which is overlaid on the flexible substrate and which contains abrasive grains, a binder, and an additive. The additive contains at least one kind of a compound represented by the general formula of ##STR1## where R.sub.1 represents a monovalent hydrocarbon group having six to 30 carbon atoms, or a fluorine-substituted alkyl group having one to 17 carbon atoms, R.sub.2 represents H or a monovalent alkyl group having one to three carbon atoms, X represents either one of ##STR2## where R.sub.3 is C.sub.3 F.sub.7 and n is an integer of 1 to 30.

Abstract: A magnetic recording medium comprising a support having provided on one surface thereof a magnetic layer, and on the opposite surface thereof a backing layer comprising nonmagnetic particles dispersed in a binder, wherein the binder in the backing layer comprises a vinyl chloride-vinyl acetate copolymer of from 50 to 80 parts by weight, a polyester resin of from 1 to 40 parts by weight, and a polyisocyanate of from 10 to 49 parts by weight, per 100 parts by weight of the binder.

Abstract: A process for preparing a magnetic recording medium by the steps of (a) forming a magnetic layer on one surface of a non-magnetic support and (b) homogeneously dispersing an .alpha.-Al.sub.2 O.sub.3 power having an average particle size of about 0.1 .mu.m or less in a solvent containing a small amount of binder to form a dispersion, mixing the thus-prepared dispersion with a binder to provide a coating composition, and applying the coating composition to the opposite surface of the nonmagnetic support to form a backing layer. The magnetic recording medium has improved wear resistance, a low friction coefficient and excellent electromagnetic properties.

Abstract: A method for preparing a magnetic recording medium comprising a non-magnetic support having thereon a magnetic layer comprised of ferromagnetic particles of hexagonal crystalline ferrite which comprises smoothing the surface of the magnetic layer and thereafter abrading the surface thereof by an abrasive tape.

Abstract: A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic layer containing magnetic particles dispersed in a binder, the binder comprising(a) a vinyl chloride polymer resin having a vinyl chloride unit in an amount of 70 wt % or more, nitrogen in an amount of from 0.01 to 1 wt % and a degree of polymerization of from 250 to 700, and(b) a polyurethane having an amino group in an amount of from 10.sup.-6 to 10.sup.-3 eq/g.

Abstract: A process for the preparation of a magnetic recording medium comprises the steps of subjecting a magnetic recording layer coated on a nonmagnetic support to surface smoothening treatment, said magnetic recording layer comprising a ferromagnetic powder dispersed in a binder, and then abrading a surface of the magnetic recording layer by means of an abrasive tape.

Abstract: A process for the preparation of a magnetic recording medium which comprises the steps of subjecting a magnetic recording layer coated on a nonmagnetic support to surface smoothening treatment, said magnetic recording layer comprising a ferromagnetic powder dispersed in a binder which is composed of a resin component and a curing agent, and then shaving a surface of said magnetic recording layer by means of a shaving device having high hardness.

Abstract: A process for the preparation of a magnetic recording disk comprises the steps of providing a magnetic recording layer on a surface of a nonmagnetic support, punching the nonmagnetic support together with the magnetic recording layer into a disk having a circular hole in its central portion, and fitting mechanical members including a center core made of a synthetic resin into the hole of the support. The nonmagnetic support having the magnetic recording layer and at least the center core of the mechanical members are subjected to heat treatment independently prior to fitting the mechanical members including the center core into the hole of the support.