The Dow Chemical Company

Dow Global Technolgoies LLC

Toyobo Co., Ltd.

Filmtec Corporation

Chieh-Chun Chau

Ritchie A Wessling

Timothy L Faley

Steven Rosenberg

Myrna Serrano

Willard E Alexander

Masaru Nakagawa

Lu H Tung

Michael E Mills

George J Quarderer, Jr

Mark D Newsham

Yoshihiko Teramoto

Jang-hi Im

Katsuya Tani

Takaharu Ichiryu

Ashish Sen

Robert A Bubeck

Stephen J Nolan

Daniel Bernardo Roitman

Mark F Sonnenschein

Henry N Beck

Tooru Kitagawa

Robert D Mahoney

Ying Hung So

Charles E Reineke

Matthew T Bishop

Steven J Martin

Hawk S Wan

Alan F Burmester

Willie E Rochefort

Hiroki Murase

Edward J Kramer

Timothy J Rehg

Ja-Young Koo

Jiro Kawamoto

Ravi B Shanker

Joel R Racchini

Katsuhiko Kato

Willard Alexander

Timothy M Finney

A low-gloss biaxially oriented polymer film containing a vinyl aromatic polymer and substantially non-spherical rubber particles is useful for window film applications. The rubber particles, when unconstrained, are essentially spherical and have a rubber particle size of 2.5 micrometers or more.

Low-gloss biaxially oriented films comprising vinyl aromatic polymers and substantially non-spherical rubber particles

A continuous process for heating a polybenzazole or polybenzothiazole filament, which includes the step of heating the filament to a temperature of at least 100.degree. C. but no greater than 290.degree. C. while applying a tension thereto of at least 3.5 grams per denier, which is carried out at a line speed of at least 100 m/minute; and there is no prior or subsequent heating of the fiber to any temperature greater than 300.degree. C. It has been discovered that placing tension on the filament while it is dried increases its tensile modulus without a significant decrease in its tensile strength.

Process for the preparation of polybenzoxazole and polybenzothiazole

The invention is a process for the preparation of polybenzazole staple fibers which includes extruding a solution of polybenzazole polymer to form a dope filament, cutting the dope filament to a desired length, and washing and drying the cut filament. It has been discovered that the process of the invention provides a suitable means to prepare staple fibers which does not require the cutting of washed, rigid polybenzazole filaments.

Process for the preparation of polybenzazole staple fiber

Described is a method for preparing a polybenzazole filament which comprises extruding a polybenzazole dope filament, drawing the filament across an air gap, coagulating and washing the filament, and drying the filament, characterized in that a solution of a compound selected from the group consisting of ferrocenes, ruthocene, iodide-, cobalt-, and copper-containing compounds, dyes, and mixtures thereof is contacted with a filament subsequent to the washing step and prior to the drying step. This method provides a means to improve the tensile strength retention of damaged polybenzazole filaments following exposure to sunlight.

Polybenzazole fibers having improved tensile strength retention

Polybenzazole fibers can be rapidly dried without undue fiber damage by exposing them to two or more set point temperatures with the temperatures being selected relative to the residual moisture content of the fiber. The residence time required for the fiber at each progressively higher temperature can be reduced if the fiber is always in full contact with the set point temperature of the drying equipment.

Method for rapid drying of a polybenzazole fiber

Improved polybenzoxazole fibers are made by a process for drying a wet, coagulated polybenzoxazole (PBO) fiber including the steps of:

Process for post-spin finishing of polybenzoxazole fibers

Improved polybenzoxazole fibers are made by a process for finishing a spun and drawn dope fiber, which contains polybenzoxazole polymer and polyphosphoric acid, including the steps of:

A process for making PBZ fibers of ultra-high physical properties is given. Polybenzoxazole fibers made by the process of this invention have tensile strengths nearly double in value from what has been reported previously.

Polybenzazole fibers with ultra-high physical properties and method for

Polybenzazole polymer dopes are spun into fibers at high speed by passing through a spinneret with proper selection of hole geometry, followed by spin-drawing to a spin-draw ratio of at least 20, washing, taking up and drying. The take up speed is at least about 150 meters per minute, and the fibers are spun in at least 10 km lengths without a break.

Method for spinning a polybenzazole fiber

Polybenzazole polymer dopes are spun through a spinneret having more than 2 per cm.sup.2, of orifices in relatively close proximity. The dope filaments formed, then pass through an air gap which has a temperature of 50.degree. to 100.degree. C. and a gas flow sufficient to uniformly reduce the temperature of the dope filaments. The filaments cool in the air gap and are then coagulated.

Method for rapid spinning of a polybenzazole fiber

This invention aims at improvement of heat-treatment technology for manufacture of large amounts of polybenzazole fibers. The fibers are heat treated in a device that provides for a rapid, cocurrent, countercurrent or both cocurrent and countercurrent flow of heat treatment gas.

Rapid heat-treatment method for polybenzaole fiber

Polybenzazole fiber with ultra-high physical properties

Improved polybenzoxazole fibers are made by a process for finishing a spun and drawn dope fiber, which contains polybenzoxazole polymer and a solvent acid, including the steps of: (a) coagulating the dope fiber in an aqueous coagulant: (b) washing the coagulated fiber with an aqueous washing fluid for less than 72 hours under conditions such that the fiber contains no more than 8,000 ppm residual solvent acid (1 ppm=1 part per million, by weight); (c) drying the fiber at a temperature of no more than 300.degree. C. until it retains no more than about 2 weight percent residual moisture; and (d) heat-treating the fiber at a temperature of at least about 300.degree. C. under tension.

The present invention relates to a process for preparing a microporous permselective membrane from a poly(phenylene sulfide) (PPS) polymer, an organic compound which substantially solubilizes the PPS below its melting point to form a homogenous mixture, heating the resulting mixture, extruding or casting the mixture into a membrane (fiber or film), quenching or coagulating the membrane, and leaching the membrane, while optionally drawing the membrane before, during, after leaching, or a combination thereof. In one embodiment, the solvent optionally includes an organic non-solvent to assist in obtaining the desired microporsity. The permselective polymers are useful to separate gaseous or liquid components from a mixture of components.

Process of making microporous hollow fiber or film membrane of

Pulps and short fibers containing polybenzoxazole and/or polybenzothiazole or copolymers thereof can be synthesized by freezing the wet fiber straight from the coagulation bath without drying, and chopping or grinding the frozen fiber to the desired size and degree of fibrillation.

Methods for synthesizing pulps and short fibers containing polybenzazole

Growing community of inventors

Midland, MI, United States of America

Chieh-Chun Chau