The present invention relates to a method for manufacturing a protein fiber, including an extension and contraction step of contracting or extending a protein raw fiber containing a protein by bringing the protein raw fiber into contact with a liquid or vapor; and a drying step of drying the protein raw fiber that has undergone the extension and contraction step while adjusting a length of the protein raw fiber to an arbitrary length.

A multi-end monofilament production apparatus includes the following sequential process units along monofilaments flow direction: a vertical spinning machine comprising a spinneret and a distribution plate below the spinneret; a water bath for quenching spun monofilaments; a vacuum jet device for transferring monofilaments from the water bath; a steam jet able to provide superheated steam at a temperature within the range between 300 C. and 380 C. and at a pressure within the range between 4 bars and 5 bars; a drawing unit; and a monofilament winder for winding monofilaments at a speed exceeding 500 m/min. The present invention further proposes a method for multi-end monofilament yarn production.

A method for manufacturing ultrafine fibers having an average diameter of less than 1 m is implemented by an apparatus including a feeder and a drawing chamber in communication with the feeder via an orifice having a pressure difference. The method includes introducing a multifilament to the drawing chamber under the condition that the ratio of the cross-section of the multifilament to the cross-section of the orifice rectifier is 50% or less, and irradiating the discharged multifilament such that the center of the multifilament melted thereby is located 1 to 15 mm apart vertically below the orifice outlet to melt the leading portion of the multifilament and cause the multifilament to swing at a maximum angle of 5 to 80 degrees to the central orifice axis within a conical space, such that the melted leading portion of the multifilament is drawn by an air stream generated by the pressure difference.

The invention is directed to carbon fibers having high tensile strength. The invention also provides a method and apparatus for making the carbon fibers. The method comprises advancing a precursor fiber through a plurality of passes through an oxidation oven, where stretching during the initial passes is minimized or eliminated entirely, or made negative, followed by controlled stretching over a series of passes, using rollers of increasing speed.

A polyvinyl alcohol fiber that can easily be fibrillated at a low manufacture cost is provided. The readily fibrillative polyvinyl alcohol fiber contains a polyalkylene oxide in addition to a polyvinyl alcohol. A mass ratio of the polyalkylene oxide ranges from 3 to 40% relative to the total mass of the polyvinyl alcohol and the polyalkylene oxide. A method for manufacturing the polyvinyl alcohol fiber is also provided.

A stretching apparatus of fibre tows in a pressurized steam environment comprises a plurality of stretching chests (1) and associated supporting structures (3, 4, 6) arranged side by side, at the same level, on a holding frame. The stretching chests (1) are each formed by two opposed metallic half-chests (1b, 1t), delimiting a stretching chamber (2). The stretching chamber (2) has a generally rectangular section of a low height and opens outwards in correspondence of the two transversal edges of the stretching chest (1) through tow entry and exit openings. Inside the stretching chambers (2) the tows are treated with saturated or overheated steam at high temperature and pressure and simultaneously undergo a mechanical stretching operation.

A stretching apparatus of fibre tows in a pressurized steam environment includes an elongated stretching chamber having a generally rectangular section of a low height, within which the tows are treated with saturated or overheated steam at high temperature and pressure and simultaneously undergo a mechanical stretching operation. The stretching chamber has a width sufficient to house multiple tows mutually flanked in a running plane and is formed within a stretching chest made of aluminum. The stretching chest is housed in a supporting structure, having a higher structural rigidity than the stretching chest, which includes a plurality of contact elements apt to determine a predefined position of the stretching chest with respect to a direction perpendicular to the tow running plane and to allow a limited mobility of the stretching chest in the other two mutually perpendicular directions which lie in the plane, length and width respectively.

System and method of producing a fiber-reinforced composite material for preventing void formation and improving mechanical properties such as strength and modulus of elasticity are described. The fiber-reinforced composite material contains a thermoplastic resin as a matrix resin and is formed using reinforcing fibers, in particular, a sheet of fiber substrate such as a woven fabric of reinforcing fibers, or a yarn bundle of a fiber substrate of reinforcing fibers. The fiber-reinforced composite material is composed of a resin-laminated substrate which includes a resin-filled substrate formed by filling spaces between fibers in a sheet or a strand of a fiber substrate with thermoplastic polyurethane filler, and a matrix resin layer composed of a thermoplastic resin disposed on the surface of the resin-filled substrate. The added amount of the thermoplastic polyurethane filler to the fiber substrate is from 10 to 30 vol % with respect to the volume of the fiber substrate.

A method for manufacturing ultrafine fibers having an average diameter of less than 1 urn is implemented by an apparatus including a feeder and a drawing chamber in communication with the feeder via an orifice having a pressure difference. The method includes introducing a multifilament to the drawing chamber under the condition that the ratio of the cross-section of the multifilament to the cross-section of the orifice rectifier is 50% or less, and irradiating the discharged multifilament such that the center of the multifilament melted thereby is located I to 15 mm apart vertically below the orifice outlet to melt the leading portion of the multifilament and cause the multifilament to swing at a maximum angle of 5 to 80 degrees to the central orifice axis within a conical space, such that the melted leading portion of the multifilament is drawn by an air stream generated by the pressure difference.

Provided are a method for producing a drawn conjugated fiber, capable of producing a conjugated fiber having a high strength and a thin fineness, and a drawn conjugated fiber. A drawn conjugated fiber is produced by performing a spinning step of obtaining an undrawn fiber having a core-sheath structure in which a core material is a resin containing, as a main component, a crystalline propylene polymer and a sheath material is a resin containing, as a main component, an olefin polymer having a melting point lower than that of the core material, by means of melt-spinning (step S1); and a drawing step of drawing the undrawn fiber (step S2).