Lubricants for elastic fiber

A method of treating an elastic fiber

• which comprises providing an elastic fiber with a spin finish for elastic fibers in an amount 0.1 to 12% by weight of the elastic fiber,
• said spin finish comprising an ionic surfactant (A) and a base oil (B) and having a surface tension (S) thereof at 25° C. of 14 to 22.5 mN/m and a volume resistivity (ρ) thereof at 20° C. of 1×107 to 1×1013 Ω cm,
• ρ and S satisfying the following relation [1]:
• ρ≦1×10(−24S+61) [1].

A method of treating an elastic fiber

• which comprises providing an elastic fiber with a spin finish for elastic fibers in an amount of 0.1 to 12% by weight of the elastic fiber, said spin finish comprising a quaternary ammonium salt (A2-11) represented by the following general formula (6), a base oil (B) and a higher fatty acid (C5-30) metal salt powder (C):
• in the formula, R11, R12 and R13 each independently is a group selected from among an alkyl, alkenyl, hydroxyalkyl and polyoxyalkylene group containing 1 to 30 carbon atoms and groups represented by the formula R5—T—R6—, R5 represents the residue of a C1-30 fatty acid after removal of the COOH group therefrom, R6 represents an alkylene or hydroxyalkylene group containing 1 to 4 carbon atoms and T represents —COO— or —CONH—;
• R14 is an alkyl, alkenyl, hydroxyalkyl or polyoxyalkylene group containing 1 to 30 carbon atoms;
• any two of R12, R13 and R14, together with N, may combinedly form a heterocyclic ring;
• and Q1 is an organic acid anion derived from an organic acid-modified silicone.