[Problem] To provide a sizing-agent-coated carbon fiber bundle in which, even when the sizing-agent-coated carbon fiber bundle has superior handling properties, the sizing agent on the sizing-agent-coated carbon fiber bundle exhibits excellent solubility in water and the adhesion amount of remaining sizing agent is reduced. [Solution] A sizing-agent-coated carbon fiber bundle obtained by applying polyethylene glycol and/or a surfactant to a carbon fiber bundle as a sizing agent, wherein all of the following conditions (i)-(iii) are satisfied. (i) The adhesion amount of the sizing agent is 0.15-0.80 parts by mass (inclusive) per 100 mass parts of the sizing-agent-coated carbon fiber bundle 100. (ii) The dry F-F friction coefficient is 0.39 or less. (iii) The adhesion amount of the sizing agent after washing for 50 seconds under the conditions disclosed in the specification is 0.12 parts by mass or less per 100 parts by mass of the sizing-agent-coated carbon fiber bundle 100.

[Problem] To provide a sizing-agent-coated carbon fiber bundle in which, even when the sizing-agent-coated carbon fiber bundle has superior handling properties, the sizing agent on the sizing-agent-coated carbon fiber bundle exhibits excellent solubility in water and the adhesion amount of remaining sizing agent is reduced. [Solution] A sizing-agent-coated carbon fiber bundle obtained by applying polyethylene glycol and/or a surfactant to a carbon fiber bundle as a sizing agent, wherein all of the following conditions (i)-(iii) are satisfied. (i) The adhesion amount of the sizing agent is 0.15-0.80 parts by mass (inclusive) per 100 mass parts of the sizing-agent-coated carbon fiber bundle 100. (ii) The dry F-F friction coefficient is 0.39 or less. (iii) The adhesion amount of the sizing agent after washing for 50 seconds under the conditions disclosed in the specification is 0.12 parts by mass or less per 100 parts by mass of the sizing-agent-coated carbon fiber bundle 100.

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

The present invention relates to a surfactant composition capable of making a liquid oil highly remain on the solid surface, which is a surfactant composition containing an anionic surfactant (A), a cationic surfactant (B), a liquid oil (C), and water, wherein the water constitutes a continuous phase; the following molar ratio R.sub.A is 0.25 or more and 0.60 or less; and the following molar ratio R.sub.b is 0.6 or more: R.sub.A: a molar ratio {(A)/[(A)+(B)]} of the amount of the anionic surfactant (A) to the total amount of the anionic surfactant (A) and the cationic surfactant (B) R.sub.b: a molar ratio {[(a1)+(b1)]/[(A)+(B)]} of the total amount of a branched-type anionic surfactant (a1) and a branched-type cationic surfactant (b1) to the total amount of the anionic surfactant (A) and the cationic surfactant (B).

The present invention relates to the field of denim fabric processing, specifically to an environmentally-friendly processing method for dyeing denim fabric with zero discharge. The method includes: step 1, a treatment of white warp yarns; step 2, a primary drying operation; step 3, a coating spray-dyeing operation; step 4, a secondary drying operation; step 5, a sizing operation; step 6, a ternary drying operation; and step 7, a doffing operation. In the present application, as warp yarns are dyed using the coating spray-dyeing technology, highly corrosive auxiliaries such as sodium hydrosulfite and sodium sulfide are not needed in the dyeing process, and the dyed warp yarns are not required to be treated in a washing tank, so that zero effluent discharge is achieved.

The present invention relates to the field of denim fabric processing, specifically to an environmentally-friendly processing method for dyeing denim fabric with zero discharge. The method includes: step 1, a treatment of white warp yarns; step 2, a primary drying operation; step 3, a coating spray-dyeing operation; step 4, a secondary drying operation; step 5, a sizing operation; step 6, a ternary drying operation; and step 7, a doffing operation. In the present application, as warp yarns are dyed using the coating spray-dyeing technology, highly corrosive auxiliaries such as sodium hydrosulfite and sodium sulfide are not needed in the dyeing process, and the dyed warp yarns are not required to be treated in a washing tank, so that zero effluent discharge is achieved.

Disclosed is a method for splitting a collar or a sleeve. Using nylon as a connecting thread guarantees the strength requirement of the connecting thread in a production process of a to-be-split semi-finished product and can dissolve the nylon via a splitting agent to split the collar or the sleeve. In the splitting agent, formic acid can dissolve the nylon and has no adverse effect to the collar and the sleeve; and a fog inhibitor can inhibit volatilization of the formic acid, so that the formic acid is acted on the nylon more effectively thus improving the utilization rate of the formic acid. The splitting agent is employed to directly act on a connecting thread of the collar or the sleeve, thus operation is convenient; and the connecting thread can be dissolved provided that the splitting agent contacts it for 1-2 s, thus splitting efficiency is high.

Disclosed is a method for splitting a collar or a sleeve. Using nylon as a connecting thread guarantees the strength requirement of the connecting thread in a production process of a to-be-split semi-finished product and can dissolve the nylon via a splitting agent to split the collar or the sleeve. In the splitting agent, formic acid can dissolve the nylon and has no adverse effect to the collar and the sleeve; and a fog inhibitor can inhibit volatilization of the formic acid, so that the formic acid is acted on the nylon more effectively thus improving the utilization rate of the formic acid. The splitting agent is employed to directly act on a connecting thread of the collar or the sleeve, thus operation is convenient; and the connecting thread can be dissolved provided that the splitting agent contacts it for 1-2 s, thus splitting efficiency is high.

A carbon fiber precursor treatment agent contains a smoothing agent that includes an amino-modified silicone, at least one onium salt selected from the group consisting of organic sulfuric acid phosphonium salts, organic sulfonic acid phosphonium salts, quaternary ammonium salts of an organic sulfuric acid having an alkyl group with not less than 3 carbon atoms in the molecule, and quaternary ammonium salts of an organic sulfonic acid having an alkyl group with not less than 3 carbon atoms in the molecule, and a nonionic surfactant.