| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a foamable fiber which can uniformly immobilize a foaming agent in a fiber aggregate in any nonwoven fabric producing process of a dry nonwoven fabric producing process such as a carding process and air-laid process, or a wet nonwoven fabric producing process such as a paper making process. <P>SOLUTION: A foamable fiber contains thermally expandable microspheres 1 and is obtained by using a polypropylene resin composition. The thermally expandable microspheres are composed of an outer shell 2 that is made from a thermoplastic resin obtained by polymerizing polymerizable components including a carboxyl group-containing monomer, and a foaming agent 3 that is included in the outer shell 2 and is vaporised by heating. The thermally expandable microspheres have an average particle diameter of 1 to 100 μm and an expansion start temperature of 170°C or more. The thermally expandable microspheres are blended at a ratio of 1 to 65 mass% to the mass of the fiber and are arranged at positions that are at least 2 μm inward from the outermost layer of a cross section of the fiber. <P>COPYRIGHT: (C)2012,JPO&INPIT |
