Sizing agent for carbon fiber, method for sizing carbon fiber by said sizing agent, sized carbon fiber and knitted or woven fabric using said carbon fiber
View Patent ↗The present invention relates to a carbon fiber sizing agent comprised of water-soluble thermoplastic resin and amphoteric surfactant within a weight ratio range of 6/1 to 1/3, a carbon fiber sizing method comprising treating carbon fibers using a sizing liquid containing the aforementioned sizing agent, sized carbon fibers comprising adhering the aforementioned sizing agent to their surfaces, and a fabric that uses said carbon fibers. The carbon fiber sizing agent of the present invention has satisfactory solubility in water over a wide pH range, and is able to impart to carbon fibers adequate convergence for forming stable chopped carbon fibers, superior workability and satisfactory uniform tow dispersibility in water over a wide pH range. Since a fabric of the present invention demonstrates affinity to water over a wide pH range, it is suitable for applications such as immersing said fabric in an aqueous matrix in order to impregnate the fabric with that matrix.
1. A carbon fiber sizing agent, comprising:
a water-soluble thermoplastic resin and an alkylimidazoline-based betaine-type amphoteric surfactant combined in a weight ratio ranging from 6/1 to 1/3.
2. The carbon fiber sizing agent according to claim 1 , wherein a water-soluble thermoplastic resin is a water-soluble nylon resin.
3. The carbon fiber sizing agent according to claim 1 , wherein the weight ratio range of water-soluble thermoplastic resin to amphoteric surfactant ranges from 2/1 to 1/2.
4. The carbon fiber sizing agent according to claim 1 , wherein the water soluble thermoplastic resin is polyvinyl alcohol, water soluble Nylon resin, water soluble urethane resin, acrylamide resin, acrylamide-vinyl acetate copolymer resin, polyacrylic ester resin or methyl cellulose.
5. A method of sizing carbon fibers, comprising:
treating carbon fibers with a sizing liquid containing the carbon fiber sizing agent according to claim 1 .
6. Sized carbon fibers, comprising:
carbon fibers whose surfaces have the carbon fiber sizing agent according to claim 1 adhered thereto.
7. The sized carbon fibers according to claim 6 , wherein the carbon fibers are chopped carbon fibers.
8. A fabric comprising the sized carbon fibers according to claim 6 .