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US 4,228,118 AGranted
Process for producing high tenacity polyethylene fibers
AssigneeMonsanto Company
InventorsWen-Li Wu, William B. Black
Life of this patent
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Abstract
Polyethylene yarns having tenacities of at least 12 grams per denier are produced at commercially feasible spinning speeds by a process in which a high density polyethylene having a M.sub.n of at least 20,000 and a M.sub.w of less than 125,000 is extruded through a high temperature spinneret (220.degree.-335.degree. C.) to form yarns which are hot-drawn at a temperature between about 115.degree. and 132.degree. C. The yarns produced by this process are particularly useful as industrial cordage.
Claims15
A process for preparing a polyethylene fiber having a tenacity of at least 12 grams per denier, comprising:
- a. extruding a high density polyethylene having a M.sub.n of at least 20,000 and a M.sub.w of less than 125,000 through a heated spinneret having at least one orifice to provide at least one molten stream, wherein said heated spinneret is maintained at a temperature between 220.degree. and about 335.degree. C.;
- b. solidifying each said molten stream in a quenching zone to form a fiber;
- c. withdrawing said fiber from said quenching zone at a velocity of at least 30 meters per minute, and then
- d. hot-drawing said fiber at a draw ratio of at least 20:1 while said fiber is in contact with a heated environment, wherein said heated environment is maintained at a temperature between 115.degree. and 132.degree. C.,
- said temperatures, said velocity, and said draw ratio being correlated to provide fiber having a tenacity of at least 12 grams per denier, when measured at 72% relative humidity and 25.degree. C. on a bundle of at least 8 filaments using a gauge length of at least 25 centimeters.
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Dependencies are inferred from the claim text.