Abstract: To improve dust removing performance and to prevent re-adhesion of dust in dust cleaner for removing dust adhering to the surface of an object such as a timepiece component by effecting blow-off dust removal and charge elimination by the use of a clean compressible fluid and an electric static ion eliminator. A clean compressible fluid is discharged from a clean compressible fluid nozzle to an object. When the object is an electro-statically charged article, an electric static ion mix clean compressible fluid containing electric static ions generated from an electric static ion eliminator is discharged to the object. It is possible to employ the structure wherein the object is set into a blow washing tray, and is moved up and down by the emission of the clean compressible fluid.

Abstract: A magnetic recording medium comprising a nonmagnetic support having thereon a lower magnetic layer and a upper magnetic layer, in this order, wherein the lower magnetic layer contains as a binder a polyurethane reisn having a number average molecular weight of less than 25,000, and the upper magnetic layer contains as a binder (a) a polyurethane resin having (i) at least three organic groups having an active hydrogen per polyurethane molecule and (ii) a number average molecular weight of 25,000 or more, and (b) a polyisocyanate.

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 magnetic recording medium comprising a nonmagnetic support having on one surface thereof a magnetic layer and on the opposite surface thereof a backing layer comprising nonmagnetic particles dispersed in a binder, wherein said binder of said backing layer comprises from about 20 to 90 wt % of polycarbonate polyurethane, and said backing layer comprises from about 40 to 200 parts by weight of said binder per 100 parts by weight of said nonmagnetic particles.

Abstract: A magnetic recording medium comprising a nonmagnetic support having thereon a magnetic layer comprising ferromagnetic particles dispersed in a binder comprising a mixture of a polycarbonate polyurethane and a phenoxy resin in a weight ratio of from about 1.5:1 to 5:1.

Abstract: Method for producing a gas separation membrane comprising a microporous support having provided thereon a non-porous coating layer. The method comprises melt extruding a thermoplastic crystalline polymer under particular melt-extrusion conditions to form a precursor in the form of a hollow fiber or flat film, coating the precursor as a support with a coating substance composed of a natural or synthetic substance capable of forming a polymeric layer which does not form pinholes upon subsequent drawing after solidification to form a coating layer on the surface of the support, and solidifying the coating layer. The support is annealed either before or after the cooling process, and this is followed by cold drawing and heat setting the support to form the gas separation membrane.

Abstract: A magnetic recording medium comprising a support having provided on one surface thereof a magnetic layer comprising a binder and ferromagnetic particles dispersed therein, and on the opposite surface thereof a backing layer comprising a binder and non-magnetic particles dispersed therein, wherein at least one of the binders comprises a vinyl chloride copolymer resin having a vinyl chloride unit content of about 70 wt % or more based on the total amount of the binder, a nitrogen content of about from 0.01 to 1 wt % based on the total amount of the binder, and a polymerization degree of about from 250 to 700; and the non-magnetic particles comprises fine carbon particles having a DBP oil absorption of about 150 ml/100 g or more.