Patent ID: 7674730

Claim:
Nonwoven fabric comprising thermoplastic elastomer fiber and thermoplastic polyolefin fiber wherein the thermoplastic polyolefin fiber in the nonwoven fabric has a fiber diameter of 25 μm or less and smaller than a fiber diameter of the thermoplastic elastomer fiber, the thermoplastic polyolefin fiber having a crystallinity that is greater than or equal to 46%; the nonwoven fabric being produced by drafting using gears within a range in which thermoplastic elastomer fiber is elastically deformable and beyond a range in which thermoplastic polyolefin fiber is elastically deformable but at a percentage of elongation causing no breakage of thermoplastic polyolefin fiber; a variation of b-value appearing in laboratory color specifying system before and after irradiation of said thermoplastic elastomer fiber with 5000KJ/m2 of UV radiation being 20 or higher; a variation of b-value appearing in laboratory color specifying system before and after irradiation of said nonwoven fabric with 5000KJ/m2 of UV radiation being 10 or less; and a relationship expressed by a following equation (1) being established: w 1 ⁢ r 2 ⁢ ρ 2 r 1 2 ⁡ ( w 1 ⁢ r 2 ⁢ ρ 2 + w 2 ⁢ r 1 ⁢ ρ 1 ) ≧ 9.7 × 10 - 4 ( Equation ⁢ ⁢ 1 ) where w1: a percentage (%) by mass of polyolefin fiber in the nonwoven fabric; r1: a radius (μm) of polyolefin fiber; p1: a density (g/cm3) of polyolefin fiber; w2: percentage (%) by mass of thermoplastic elastomer fiber in the nonwoven fabric; r2: a radius (μm) of thermoplastic elastomer fiber; and p2: a density (g/cm3) of thermoplastic elastomer fiber.