Other

Minnesota Mining and Manufacturing Company

3m Innovative Properties Company

3m Innovation Properties Company

David A Olson

Michael R Berrigan

John M Brandner

John F Reed

Robert J Wolf

Pamela A Percha

Delton R Thompson, Jr

Scott M Purrington

Thomas I Insley

Andrew R Fox

Wayne Scott Mahoney

Marvin E Jones

Daniel E Meyer

Eric M Moore

Fuming B Li

Bradley W Eaton

John M Sebastian

Myles Lee Brostrom

Jonathan H Alexander

Justin L Keough

Gerald L Van Dam

David C Brownlee

Philip A Anderson

Ronald R Gorke

David L Nelson

Methods of preparing polymeric webs include hot melt blending of thermoplastic resins and processing aids. The process aids include hindered amine N-substituted succinimide oligomers. The webs prepared from the blends may be in the form of films or non-woven fibrous webs. Non-woven microfiber webs are useful as filtration media. Among the polymeric webs produced are electret webs. The processing aids also function as charge-enhancing additives for the electret webs.

Processing aids for olefinic webs, including electret webs

A reactor for hydrolytic splitting of cellulose under high pressure and heat has an inlet and outlet each with a cross-sectional area smaller than the cross-sectional area of the reactor. The pressure and heat in the reactor forms a cellulose plug within the inlet and the outlet. The inlet plug stops cellulose from escaping out the inlet. Cellulose begins to breakdown under heat, pressure, and if required an acid or a lubricant. The outlet plug slows downstream movement of cooking cellulose. Cellulose may be pre-treated by the addition of water, a weak acid, a lubricant, or a combination of the foregoing. The outer surface of the plug cooks faster than the inner core of the plug, becomes a liquefied slurry, and slides faster towards the outlet than the inner core.

Reactor pump for catalyzed hydrolytic splitting of cellulose

The reactor pump for hydrolytic splitting of cellulose is configured to pump cellulose, under high pressure, with low availability of sugar into a reactor. The reactor has an upstream transition segment connected to a downstream reaction chamber. The transition segment has an inlet that is smaller than the outlet. The inner walls taper outward. The chamber has an inlet that is larger than the discharge outlet. The inner walls taper inward. The transition segment outlet has an area that is substantially the same as the area of the chamber inlet. Back pressure in the chamber forms a cellulose plug within the inlet of the transition segment. The plug stops cellulose from escaping out the inlet. High pressure pumping forms a cellulose plug within the discharge outlet of the chamber. The plug slows downstream movement of the cooking cellulose giving the cellulose time to cook. Cooking cellulose begins to breakdown under heat and the injection of acid, if required. The outer surface of the plug is cooked faster than the inner core and in the process the faster cooking portion of the plug becomes a liquefied slurry. The slurry lies between the inwardly tapering chamber walls and the less cooked inner core. The slurry slides faster towards the discharge outlet than does the inner core. As the slurry moves downstream in the chamber, the surface of the inner core moves to the walls and in turn is liquefied. Cellulose may be pre-treated prior to entry in the reactor by the addition of water and a weak acid such as sulfuric or ammonium. The cellulose may be granulated to provide more surface area to assist break down in the reactor.

Multilayer articles having acoustical absorbance properties are disclosed. Methods of making and using the multilayer articles are also disclosed.

Multilayer articles having acoustical absorbance properties and methods of making and using the same

A new acoustic insulating sheet material comprises in laminar assembly a) a primary sound absorbing sheet, and b) a dense porous membrane that i) has an air-flow resistance of about 5000 rayls or less and ii) has an Acoustic Value Ratio as defined herein of at least 3000. Preferably, the membrane is about 200 micrometers or less in thickness, and more preferably is about 150 micrometers or less in thickness. Also, the Acoustic Value Ratio is preferably at least 7,000. The described membrane can also be used alone to acoustically insulate a space, e.g., by mounting it in planar array over an air gap and in position to attenuate noise from a noise source.

Porous membrane

New nonwoven fibrous webs are taught which comprise a collected mass of a) directly formed fibers disposed within the web in a C-shaped cross-sectional configuration and b) staple fibers having a crimp of at least 15% dispersed among the directly formed fibers in an amount of at least 5% the weight of the directly formed fibers. The web is lofty but free of macrovoids. Preferably, the web has a filling ratio of at least 50 and a light transmittance variation of about 2% or less. Typically, fibers within the web are bonded together at points of fiber intersection, preferably with autogenous bonds, to provide a compression-resistant matrix. The webs are especially useful as acoustic and thermal insulation.

Fibrous nonwoven web

A viscous material (sludge) pump, a method of accurately estimating output of such a pump and a method of efficiently managing such a pump. The pump can be the single or double cylinder variety. The pump is calibrated to determine a calibrated sludge-weight output of the pump in terms of a parameter defined as a &ldquo;lost travel&rdquo; position of the piston in the pump chamber. This position is defined in terms of the position of the piston in the chamber when the pressure in the chamber reaches a preselected reference pressure expressed in terms of a percentage of the maximum pressure reached in the chamber during a just previous discharge stroke of the piston. The lost travel parameter is used for comparison purposes to accurately estimate actual pump output based on the calibrated pump output at the calibrated value of the lost travel parameter. The pump is managed efficiently by management of the speed of the feed auger. This assures that an approximately optimal amount of material is loaded into the pumping chamber each pumping cycle. The pump is also managed by management of the pump stroke distance and speed.

Sludge pump with management system

New fibrous nonwoven webs are taught that comprise a mass of polyethylene terephthalate fibers that exhibit a double melting peak on a DSC plot: one peak is representative of a first molecular portion within the fiber that is in non-chain-extended crystalline form, and the other peak is representative of a second molecular portion within the fiber that is in chain-extended crystalline form and has a melting point elevated over that of the non-chain-extended crystalline form. Webs comprising fibers having such a morphology have a unique combination of durability and dimensional stability. The fibers are generally autogenously bonded at points of fiber intersection.

Fibrous nonwoven webs

A method and apparatus for tentering nonwoven webs during annealing. The nonwoven web of thermoplastic fibers is restrained on a tentering structure at a plurality of tentering points distributed across an interior portion of the web, rather than just along its edges. The nonwoven web is annealed while restrained on the tentering structure to form a dimensionally stable nonwoven fibrous web, dimensionally stable up to at least the heatsetting temperature. The annealed nonwoven fibrous web is then removed from the tentering structure. In one embodiment, the tentering structure restrains the nonwoven fibrous web in a non-planar configuration during the annealing process. The tentering structure includes a plurality of tentering points projecting distally from a tentering support. The tentering points are positioned to be engaged with an interior portion of the web, thus restraining the web during annealing.

Apparatus for making dimensionally stable nonwoven fibrous webs

Method for making dimensionally stable nonwoven fibrous webs

A barrier fabric laminate for use as a coating for a gel filled article is provided. The barrier fabric laminate comprises a fluid impermeable film and a polyurethane nonwoven web which has a friction value of less than 200 g and a fabric hand of less than 200 g. The polyurethane web is formed of fibers of less than about 50 .mu.m on average and preferably is formed with a fluorochemical melt additive by sequentially melt blowing the polyurethane web on a heated collecting drum and laminated by a nip formed by a heated nip roller and the collecting drum.

Method of making a polyurethane pad covering

Polyurethane pad covering

Filter media is provided. The filter media comprises a web of melt blown microfibers having one surface substantially flat and the other surface having periodic wrinkle-like undulations. A method of making the filter media is also provided. The filter media is useful in electret filters when charged.

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Saint Paul, MN, United States of America

David A Olson