A method for fusing aramid fibers, wherein a) at least one area of an aramid fiber is treated with an ionic liquid so that the aramid is partially dissolved, b) the aramid fiber is contacted via the dissolved area with another aramid fiber area with pressure being applied to the contact area, and subsequently c) the partially dissolved area of the aramid is re-coagulated.

A lightweight heat-preserving fiber and a preparation method thereof are provided, wherein the fiber is prepared by measuring, composite spinneret's extruding, cooling, oiling, drawing, heat setting and winding a polyester melt. The composite spinneret has a hollow spinning hole and a circular spinning hole. The ratio of the micropore length of hollow spinning hole to circular spinning hole equals to the ratio of the equivalent diameter of hollow spinning hole to circular spinning hole multiplies the coefficient K, and the equivalent diameter is the ratio of the cross-sectional area to the circumference of the cross-section, the coefficient K ranges from 0.97 to 1.03. The oil agent contains a crown ether, and the content of the crown ether ranges from 67.30 to 85.58 wt %. The thermal conductivity of a knitted fabric having a basis weight of 100 g/m.sup.2 prepared by lightweight heat-preserving fiber is no larger than 0.150 W/m.Math.K.

Various embodiments disclosed relate to an aqueous dispersion. The aqueous dispersion includes a plurality of particles. Each of the particles includes a polycarbonate component. Individual particles of the polycarbonate component have substantially the same size. The dispersion further includes a plasticizer component and a surfactant component. In an embodiment, a sized carbon fiber tow can comprise: a polycarbonate sizing on a carbon fiber tow, wherein the polycarbonate sizing has a concentration of volatile organic compounds less than 10 ppm, preferably less than 5 ppm, or less than 2 ppm; and an average sizing content of at least 0.5 wt % of the carbon fiber tow with a coefficient of variation less than 15%, preferably less than 11%.

Various embodiments disclosed relate to an aqueous dispersion. The aqueous dispersion includes a plurality of particles. Each of the particles includes a polycarbonate component. Individual particles of the polycarbonate component have substantially the same size. The dispersion further includes a plasticizer component and a surfactant component. In an embodiment, a sized carbon fiber tow can comprise: a polycarbonate sizing on a carbon fiber tow, wherein the polycarbonate sizing has a concentration of volatile organic compounds less than 10 ppm, preferably less than 5 ppm, or less than 2 ppm; and an average sizing content of at least 0.5 wt % of the carbon fiber tow with a coefficient of variation less than 15%, preferably less than 11%.

A method for welding aramid fibers, wherein a) at least one area of an aramid fiber is treated with an ionic liquid so that the aramid is partially dissolved, b) the aramid fiber is contacted via the dissolved area with another aramid fiber area with pressure being applied to the contact area, and subsequently c) the partially dissolved area of the aramid is re-coagulated.

A method for welding aramid fibers, wherein a) at least one area of an aramid fiber is treated with an ionic liquid so that the aramid is partially dissolved, b) the aramid fiber is contacted via the dissolved area with another aramid fiber area with pressure being applied to the contact area, and subsequently c) the partially dissolved area of the aramid is re-coagulated.

A head cover that can be worn by health care professionals is provided. The head cover includes an anterior portion with a height h, a posterior portion with a height h.sub.2, at least one side portion or panel which may be shaped and sized so as to connect the anterior portion of the head cover and the posterior portion of the head cover, and where the at least one side portion has a contoured section t that forms all or a portion of a bottom edge of the side portion and that is shaped and sized so as to cover the ears, scalp, and sideburns of a user as required by AORN guidelines while also remaining clear of a user's eyes and field of vision.

A head cover that can be worn by health care professionals is provided. The head cover includes an anterior portion with a height h, a posterior portion with a height h.sub.2, at least one side portion or panel which may be shaped and sized so as to connect the anterior portion of the head cover and the posterior portion of the head cover, and where the at least one side portion has a contoured section t that forms all or a portion of a bottom edge of the side portion and that is shaped and sized so as to cover the ears, scalp, and sideburns of a user as required by AORN guidelines while also remaining clear of a user's eyes and field of vision.

A bi-profiled fiber and preparing method thereof are provided. The bi-profiled fiber is manufactured through the steps of spinning melt metering, extruding via the composite spinneret, cooling, oiling, drawing, heat setting and winding, finally containing both double-cross monofilaments and circular monofilaments simultaneously. The bi-profiled fiber is made of the modified polyester, and the modified polyester is dispersed by matte agent and is composed of terephthalic acid segments, ethylene glycol segments and branched diol segments, and the branched diol segment has a structural formula of

##STR00001## where R.sub.1 and R.sub.2 are separately selected from the linear alkylene with 1-3 carbon atoms, R.sub.3 from the alkyl with 1-5 carbon atoms, and R.sub.4 from the alkyl with 2-5 carbon atoms. The matte agents is a mixture of amorphous titanium dioxide and amorphous silicon dioxide, or a mixture of calcium carbonate and amorphous silicon dioxide.

A bi-profiled fiber and preparing method thereof are provided. The bi-profiled fiber is manufactured through the steps of spinning melt metering, extruding via the composite spinneret, cooling, oiling, drawing, heat setting and winding, finally containing both double-cross monofilaments and circular monofilaments simultaneously. The bi-profiled fiber is made of the modified polyester, and the modified polyester is dispersed by matte agent and is composed of terephthalic acid segments, ethylene glycol segments and branched diol segments, and the branched diol segment has a structural formula of

##STR00001## where R.sub.1 and R.sub.2 are separately selected from the linear alkylene with 1-3 carbon atoms, R.sub.3 from the alkyl with 1-5 carbon atoms, and R.sub.4 from the alkyl with 2-5 carbon atoms. The matte agents is a mixture of amorphous titanium dioxide and amorphous silicon dioxide, or a mixture of calcium carbonate and amorphous silicon dioxide.