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US 6,656,404 B2Granted
Methods of making low-shrink polypropylene fibers
AssigneeMilliken & Company
InventorsBrian G. Morin, Nathan A. Mehl, William S. Parks
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AssigneeMilliken & Company
InventorsBrian G. Morin, Nathan A. Mehl, William S. Parks
Estimating the term…
Improved polypropylene fibers exhibiting greatly reduced heat- and moisture-shrink problems and including certain compounds that quickly and effectively provide rigidity to the target polypropylene fiber after heat-setting are disclosed herein. In such a manner, the “rigidifying” compounds provide nucleation sites for polypropylene crystal growth. After drawing the nucleated composition into fiber form, the fiber is then exposed to sufficient heat to grow the crystalline network, thus holding the fiber in a desired position. The preferred “rigidifying” compounds include dibenzylidene sorbitol based compounds, as well as less preferred compounds, such as sodium beuzoate, certain sodium and lithium phosphate salts (such as sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate, otherwise known as NA-11).
A method of producing a polypropylene fiber exhibiting a shrinkage at 150° C. in hot air of at most 7%, said method comprising the sequential steps of
A method of producing a polypropylene fiber exhibiting a shrinkage at 100° C. in boiling water of at most 3%, said method comprising the sequential steps of
A method of producing a polypropylene fiber, said method comprising the sequential steps of
Dependencies are inferred from the claim text.