Abstract: A differential signal transmission cable includes two core wires, and a foamed insulation that collectively covers the two core wires by foaming extrusion molding. The foamed insulation is not more than 5% in a dispersion of foaming degree defined below in a cut surface when the cable is cut orthogonally to a longitudinal direction of the cable. In the cut surface, five regions are determined according to a predetermined procedures and a foaming degree (%) of the respective regions is measured. The dispersion of the foaming degree is defined by a difference between a foaming degree (%) in the region with a maximum foaming degree and a foaming degree (%) in the region with a minimum foaming degree.

Abstract: A differential signal transmission cable includes a pair of differential signal lines arranged in parallel to each other, an insulation for bundle-covering the pair of differential signal lines, and a shield conductor wound around an outer periphery of the insulation. The insulation is configured such that an outer circumference thereof in a cross section perpendicular to a longitudinal direction thereof has an oval shape formed with a continuous convex arc-curve. The outer circumference of the insulation includes a first curved portion with a pair of symmetrical elliptical arcs located at both ends in a first direction along the arrangement direction of the pair of differential signal lines and a second curved portion with a pair of symmetrical elliptical arcs located at both ends in a second direction orthogonal to the first direction.

Abstract: A differential signal transmission cable includes a pair of differential signal lines arranged in parallel to each other, an insulation for bundle-covering the pair of differential signal lines, and a shield conductor wound around an outer periphery of the insulation. The insulation is configured such that an outer circumference thereof in a cross section perpendicular to a longitudinal direction thereof has an oval shape formed with a continuous convex arc-curve. The oval shape has a width in a first direction along the arrangement direction of the pair of differential signal lines being larger than a width in a second direction orthogonal to the first direction.

Abstract: An insert molding method includes holding a plurality of insert members in a molding die to be separated from one another, and subsequently filling a resin into the molding die to fill a gap between the insert members and a periphery thereof with the resin to form an insert molded product such that the insert members are separated at a preset interval from one another. The molding die includes a space-maintaining projection for maintaining a separation interval between the insert members at the preset interval or more, the projection being formed on an inner wall surface of the molding die opposite to a longitudinal end of the insert members, and a gate for filling the resin therethrough into the molding die, the gate being formed on an inner wall surface of the molding die opposite to a side of the insert members in a width direction thereof.

Abstract: A differential transmission cable includes at least one pair of inner conductors arranged in parallel and extending parallel to each other, and a foamed insulating material formed on the inner conductors by a collective extrusion coating and molding of a resin material by using a chemical foaming method and have a variation of foaming degree of not more than 1%. The variation of foaming degree is defined as a difference between a maximum value and a minimum value among foaming degrees (%) of the foamed insulating material at 20 positions at intervals of 50 cm in a longitudinal direction in an arbitrary part of 10 m cut out from the differential transmission cable.

Abstract: A parallel foamed coaxial cable includes one or more pairs of inner conductors aligned in parallel, a foamed insulation covering together the inner conductors and having a cross sectional shape including an elliptical shape, a rounded-rectangular shape or a quasi-elliptical shape formed by combining a plurality of curved lines, a non-foamed skin layer covering the foamed insulation and having a maximum thickness in a major axis direction of the cross sectional shape of the foamed insulation and a minimum thickness in a minor axis direction of the cross sectional shape of the foamed insulation, an outer conductor covering the non-foamed skin layer, and an insulation jacket covering the outer conductor. The maximum thickness of the non-foamed skin layer is not less than 1% of a major axis of the cross sectional shape of the foamed insulation.

Abstract: A differential signal transmission cable includes a pair of differential signal lines arranged in parallel to each other, an insulation for bundle-covering the pair of differential signal lines, and a shield conductor wound around an outer periphery of the insulation The insulation is configured such that an outer circumference thereof in a cross section perpendicular to a longitudinal direction thereof has an oval shape formed with a continuous convex arc-curve The oval shape has a width in a first direction along the arrangement direction of the pair of differential signal lines being larger than a width in a second direction orthogonal to the first direction

Abstract: A foamed resin composition includes syndiotactic polystyrene, and a polyolefin resin of not less than 5.3 parts by weight and not more than 54 parts by weight relative to 100 parts by weight of the syndiotactic polystyrene. Alternatively, a foamed resin composition includes syndiotactic polystyrene, and fluorine-resin-containing powder of not less than 0.5 parts by weight and not more than 10 parts by weight relative to 100 parts by weight of the syndiotactic polystyrene.

Abstract: An insert molding method includes holding a plurality of insert members in a molding die to be separated from one another, and subsequently filling a resin into the molding die to fill a gap between the insert members and a periphery thereof with the resin to form an insert molded product such that the insert members are separated at a preset interval from one another. The molding die includes a space-maintaining projection for maintaining a separation interval between the insert members at the preset interval or more, the projection being formed on an inner wall surface of the molding die opposite to a longitudinal end of the insert members, and a gate for filling the resin therethrough into the molding die, the gate being formed on an inner wall surface of the molding die opposite to a side of the insert members in a width direction thereof.