Kabushiki Kaisha Toyoda Jidoshokki Seisakusho

Other

Tomohito Ito

Fukuo Gomi

Renichi Isomura

Hidetoshi Hirai

Senichi Masuda

Takashi Yoshida

Mitsuyoshi Shirotani

A process for producing fiber aggregate which comprises the steps of coating a conductive material which is insoluble in a dielectric fluid on the surface of fibers; dispersing the fibers into the dielectric fluid to obtain a fiber suspended fluid; introducing the fiber suspended fluid into an electric field which is generated in a space between a positive electrode and a negative electrode, whereby causing individual fibers to electrostatically and one-dimensionally orient; and aggregating the oriented fibers. The conductive material contributes to charge-transfer, and it causes the fibers in the electric filed to orient stably.

Process for producing fiber aggregate

An apparatus for producing annular fiber aggregate includes: a container including an inner cylinder and an outer cylinder disposed concentrically, whereby forming an upright cylindrical space between the inner cylinder and the outer cylinder; at least a pair of positive electrode and negative electrode disposed by turns and buried in the wall of the outer cylinder, parallely with respect to the axis of the upright cylindrical space; a filter member disposed at the lower portion of the upright cylindrical space; and a voltage applicator connected to the positive electrodes and the negative electrodes. Since the apparatus has the positive and negative electrodes buried in the wall of the outer cylinder, the fibers are hardly disturbed and lifted by the positive and negative electrodes even when the positive and negative electrodes are rotated relatively around the axis of the upright cylindrical space. Thus, a fiber aggregate can be obtained in which the fibers are oriented in the peripheral tangent direction uniformly and favorably, and the strength thereof in the direction perpendicular to the peripheral tangent direction has been further enhanced.

Apparatus for producing annular fiber aggregate

The present invention relates to a process for producing fiber aggregate which comprises a dispersion step of dispersing fibers in the form of short fiber, whisker, or a mixture thereof into a dielectric fluid; an orientation step of placing the dielectric fluid containing said fibers dispersed therein in a space between a positive electrode and a negative electrode across which a high voltage is applied, whereby causing individual fibers in the dielectric fluid to electrostatically orient, with one end pointing to the positive electrode and the other end pointing to the negative electrode; and an aggregating step of aggregating the statically oriented fibers while keeping the oriented step, whereby producing fiber aggregate in which said fibers are mostly one-dimensionally oriented. Small amounts of surface active agent in the dielectric liquid promote fiber orientation in addition to dispersing the fibers.

The present invention relates to a process for producing fiber aggregate which includes an orientation step of placing the dielectric fluid containing fibers in the form of short fiber, whisker, or a mixture thereof dispersed therein in a space between a pair of electrodes across which an AC voltage is applied, whereby causing individual fibers in the dielectric fluid to electrostatically orient, with one end pointing to one of electrodes and the other end pointing to the other electrode; and an aggregating step of aggregating the electrostatically oriented fibers while keeping the oriented step, whereby producing fiber aggregate in which the fibers are substantially one-dimensionally oriented.

A fiber aggregate in which many of the fibers are oriented in the tangent direction of the circumference satisfactorily can be produced by a process and an apparatus according to the present invention. The best feature of the present invention is the following arrangement for a plurality of electrodes used in a process and an apparatus according to the present invention. Vertically extending foil, net or needle-shaped electrodes for orienting the fibers electrostatically are disposed alternately along the circumference of the vertically cylindrical space so as to divide the vertically cylindrical space into equal parts. In addition to this arrangement, the plurality of electrodes may be rotated as well as moved vertically in order not to disturb the fiber aggregation. A fiber aggregate obtained by the present invention has an improved strength and anti-thermal properties.

Apparatus for producing a fiber aggregate

The feature of the present invention is that a fiber mixture of silicon carbide or silicon nitride whiskers and alumina or alumina-silica short fibers with 1 to 45 volume percent of the short fibers in relation to the total volume of the whiskers and short fibers is used in the following steps for producing a fiber aggregate: a dispersion step of dispersing whiskers and short fibers into a dielectric fluid; an orientation step of placing the dielectric fluid containing the fibers dispersed therein in a space between a positive electrode and a negative electrode across which a high voltage is applied, whereby causing individual fibers in the dielectric fluid to electrostatically orient, with one end pointing to the positive electrode and the other end pointing to the negative electrode; and an aggregating step of aggregating the electrostatically oriented fibers while keeping the oriented step. The fiber mixture is used in order to grow the bridgings of whiskers around the short fibers as cores. Thus the fiber sedimentation is accelerated by densely bridged fibers while maintaining a satifactory orientation. Hence a whisker aggregate with a larger fiber volume ratio Vf can be formed in a shorter period of time.

Process for producing a fiber aggregate

The present invention relates to a process for producing fiber aggregate which comprises a dispersion step of dispersing fibers in the form of short fiber, whisker, or a mixture thereof into a dielectric fluid; an orientation step of placing the dielectric fluid containing said fibers dispersed therein in a space between a positive electrode and a negative electrode across which a high voltage is applied, whereby causing individual fibers in the dielectric fluid to statistically orient, with one end pointing to the positive electrode and the other end pointing to the negative electrode; and an aggregating step of aggregating the statically oriented fibers while keeping the oriented step, whereby producing fiber aggregate in which said fibers are mostly one-dimensionally oriented.

The present invention relates to an apparatus for continuously producing one-dimensionally oriented fiber aggregate in which an orientation vessel includes a case, a supply portion, an orientation portion, a discharge portion, at least one pair of electrodes disposed on the orientation portion of the vessel, and a sheet drive unit. A dielectric fluid in which whiskers and/or short fibers are dispersed is supplied downwardly, and the fibers oriented one-dimensionally by means of high voltage applied across electrodes disposed in an orientation vessel. The sheet drive unit moves a long filter sheet disposed horizontally between the orientation portion and the discharge portion of the orientation vessel to enable the dielectric liquid to pass the filter sheet to the discharge portion of the vessel, and permitting the fibers to aggregate on the sheet.

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Ohbu, Japan

Tomohito Ito