Appeal No. 1997-0958
Application 08/300,669
nonelected invention.
THE INVENTION
Appellants claim a process for producing elastane fibers
from polyurea polyurethanes wherein recited amounts of a
polydimethylsiloxane and an ethoxylated polydimethylsiloxane
are added to the spinning solution before the solution is spun
to form the fibers. Appellants state that these additives
cause distinctly less streaking in dyed and finished textiles
(specification, page 2, lines 18-30). Claim 10 is
illustrative and reads as follows:
10. In the production of elastane fibers from polyurea
polyurethane by dry spinning or wet spinning, removing the
spinning solvent, finishing, optionally twisting a solution
thereof to form filaments winding the spun filaments, the
improvement which comprises adding to the spinning solution
before spinning,
A) from 0.8 to 2% by weight of polydimethylsiloxane with
a viscosity of 50 to 300 cSt and
B) from 0.2 to 0.6% by weight of ethoxylated
polydimethylsiloxane with a viscosity of 20 to 150 cSt
(viscosities measured with a falling ball viscosimeter at
25EC) the percentages being based on the siloxane content of
the final fiber, whereby fabrics formed of the resulting yarn
exhibit reduced defects when dyed.
2
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