International Paper Company

Martin Allen Hubbe

Erwin R Ruckel

Khaim Lisnyansky

Dinkar G Wagle

William L Olsen

Hui Zhu

A method and apparatus for determining electrokinetic properties of a papermaking furnish includes mixing a sample of furnish in a container with a known amount of a charged additive and then measuring the streaming potential of the resultant ionically modified furnish sample. The amount of charged additive added to the container is increased or decreased as repeated streaming potential measurements are made until a desired streaming potential of the modified furnish sample is obtained. The results, which are expressed as the amount of titrant required to achieve the desired streaming potential in a given volume of furnish, may be used by papermakers to adjust process variables and achieve optimum, stable paper quality and machine runnability.

Method for determining electrokinetic properties of papermaking furnish

A method for enhancing the freeness of pulp made from secondary fiber is provided by adding an enzymatic mixture comprised of cellulase and pectinase enzymes to the pulp and treating under conditions to cause a reaction to produce an enzymatically treated pulp. The freeness of the enzymatically treated pulp is increased from the initial freeness of the secondary fiber pulp without a loss in brightness.

Method of improving pulp freeness using cellulase and pectinase enzymes

Processes for increasing the strength of cellulosic fibers are carried out by contacting relatively dry cellulosic fibers with an agent in particulate or vapor form comprising a carboxylic acid cyclic anhydride at an elevated temperature for a time sufficient to significantly increase the bonding strength of the fibers. The treated fibers bond more readily to one another and they also hold wet and dry strength aids more strongly. Furthermore, the treatment does not significantly affect the internal chemical structure of the fibers so that paper made from the fibers exhibits overall improved dimensional stability.

Method for increasing the strength of a paper or paperboard product

An apparatus for determining an electrical characteristic of a papermaking furnish includes a sample chamber having first and second sections for containing a sample of the papermaking furnish. A fiber-collecting screen having a mesh sufficient to inhibit the passage of suspended fibers separates the first and second sections of the sample chamber. Furnish is urged back and forth through the screen in a plurality of cycles so that as furnish flows in one direction through the screen, a fiber pad is formed adjacent the screen and as furnish is moved through the screen in a second direction, the fiber pad is expelled from the screen back and redispersed back into the furnish sample. A stirrer or mixer assists in removing the fiber pad from the screen and in redispersing fibers comprising the fiber pad back into the furnish sample. As furnish is urged through the screen, electrodes positioned on opposite sides of the screen produce signal outputs corresponding to an electrical characteristic of the furnish. A voltmeter receives the electrode outputs and measures voltage across the screen. In one embodiment, furnish is moved through the screen by means of a variable volume chamber in fluid connection with the screen and furnish. In an alternate embodiment, fluid is urged through the screen by reciprocating the screen within the furnish sample. Colloidal charge of the furnish may be determined by moving furnish through the screen in repeated cycles as the furnish sample is titrated with a highly charged additive.

Method and apparatus for measuring an electrical property of papermaking

Systems for the on-line optical measurement of properties of a translucent moving web, such as paper or plastic, as it is continually produced, colored or otherwise converted. Measured properties include color, reflectance and opacity. A backing roll has a cylindrical or approximately cylindrical surface which comprises at least one optical standard. The roll is positioned such that a circumferential portion of the roll surface contacts the back web surface where the web characteristic is to be measured, with the web curving around the circumferential portion. An optical sensing device is positioned so as to view the front web surface backed by the optical standard or standards. In several embodiments, two sets of reflectance data are collected, one with a 'white' optical standard backing and the other with a 'black' optical standard backing. The backing roll surface and the optical sensing device can be arranged such that the sensing device either alternately or simultaneously views portions of the front web surface backed by each of the optical standards. In other embodiments, the backing roll has a uniform optical standard surface.

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Campbell Hall, NY, United States of America

Martin Allen Hubbe