Poly(vinylidene fluoride) yarns and fibers
AssigneeRhone-Poulenc-Textile
InventorsPierre Chion, Robert Cuidard
Life of this patent
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Abstract
A process of making polyvinylidene fluoride yarns and fibers of homogeneous structure and good dry strength includes the steps of spinning the solution of the polymer into a coagulating bath containing 45 to 60% by weight aprotic polar organic solvent and 40 to 55% by weight water, stretching the filaments in air to a ratio of 1.5 to 5x and then in boiling water to a ratio of 1.5 to 4x (overall stretching ratio of 3x to 6.5x) and then washing in water at room temperature.
Claims3
Polyvinylidene fluoride yarns and fibers having a dry tenacity of at least 33 g/tex and an improved structure as measured by their secondary swelling values of up to 20% prepared by
- spinning a solution of polyvinylidene fluoride having a fluidity index at 250.degree. C of at least 10 into a coagulating bath containing 45 to 60% by weight of an aprotic polar organic solvent and 40 to 55% by weight of water maintained at a temperature between 15.degree. and 40.degree. C,
- stretching the filaments in air at a temperature between 15.degree. and 40.degree. C to a ratio of between 1.5.times. and 5.times.,
- then stretching the filaments in boiling water to a ratio of between 1.5.times. and 4.times., the overall stretch ratio being between 3.times. and 6.5.times., and
- then washing the filaments with water maintained at a temperature between 15.degree. C and 40.degree. C at room temperature.
Dependencies are inferred from the claim text.