Partially separated fiber bundle and method of manufacturing same, chopped fiber bundle using same, and fiber-reinforced resin forming material

A method of manufacturing a partially separated fiber bundle, comprising:

• fiber separation step [A] of generating fiber separation parts by stabbing a fiber separation means provided with a plurality of projections into a fiber bundle consisting of a plurality of single yarns and runs along a longitudinal direction;
• interlacing step [B] of forming an interlaced section at which the single yarns interlace a contact part of the projection in at least one of the fiber separation parts;
• partial fiber separation step [C] taking the fiber separation means off the fiber bundle and again stabbing the fiber separation means into the fiber bundle after passing through an accumulated interlaced section so that separated fiber sections and unseparated fiber sections are formed alternately;
• and
• resin impregnation step [D] adding a water-soluble polyamide to the fiber bundle,
• wherein the resin impregnation step [D] is performed after opening and widening the fiber bundle consisting of a plurality of single yarns.

A method of manufacturing a partially separated fiber bundle, comprising:

• fiber separation step [A] of generating fiber separation parts by stabbing a fiber separation means provided with a plurality of projections into a fiber bundle consisting of a plurality of single yarns and runs along a longitudinal direction;
• interlacing step [B] of forming an interlaced section at which the single yarns interlace a contact part of the projection in at least one of the fiber separation parts;
• partial fiber separation step [C] taking the fiber separation means off the fiber bundle and again stabbing the fiber separation means into the fiber bundle after passing through an accumulated interlaced section so that separated fiber sections and unseparated fiber sections are formed alternately;
• and
• resin impregnation step [D] adding a water-soluble polyamide to the fiber bundle,
• wherein the fiber bundle is impregnated with the water-soluble polyamide of 0.1 to 20 wt % dissolved in a solvent to prepare a polymer solution in the resin impregnation step [D].