Abstract: A mathematical model is used to design paper and paperboard having improved runnability. The mathematical model provides an estimate of fracture toughness for an optimized paper product based on specific measurement parameters, e.g., filler percent, softwood content and caliper for optimal fracture toughness. After the optimizing set of measurement parameters has been acquired, these parameters can be used to manufacture grades of paper having improved runnability performance, e.g., in printing presses.

Abstract: The invention relates to methods for reducing the amount of halogenated organics produced during a halogen bleaching process for lignocellulosic pulp fibers. According to the disclosed invention, it has been discovered that the use of a chelating agent prior to a non-halogen containing bleaching stage of a pulp bleaching process is effective to increase the brightness of the resulting bleached pulp without the need to increase the amount of halogen compounds required to obtain the same pulp brightness and without adversely affecting the pulp viscosity and yield.

Abstract: The invention relates to a process for continuous cooking of wood chips at elevated pressure and temperature in a vertical digester (1) for production of chemically dissolved pulp. Fiber material and cooking liquor are introduced at the top of the digester and pulp is discharged from the bottom of the digester (1), via a line (8) in which the pulp is maintained at substantially the same pressure level, to a pressurized wash (7). More than 50% of the used cooking liquor (black liquor) which is extracted from the system in total is extracted from the wash filtrate of the pressurized wash. The pressurized wash is regulated so that a high temperature is maintained in the wash filtrate. The extraction is regulated so that a net co-current flow is established at the bottom of the digester.

Abstract: A method for brightening chemical pulps with less than 18% lignin utilizing a magnesium compound in a sodium silicate solution to form a higher percentage of high molecular weight silicates. Such high molecular weight silicates preferentially adsorb transition metal impurities, which, if left in solution, would tend to decompose hydrogen peroxide and organic peroxides. Hydrogen peroxide is added to peroxide and peroxide/oxygen stages, while it is generated, along with organic peroxides during an oxygen stage.

Abstract: A process for the bleaching of lignin present in pulp fibers in an aqueous environment such as a pulp suspension. The invention also relates to a process for producing paper or board from pulp containing bleached lignin. According to the invention carbon dioxide is used for the bleaching of lignin.

Abstract: A method is provided for deinking paper. Repulped paper is treated with a deinking comprising a triglyceride. A preferred triglyceride is beef tallow. The deinking composition reduces foaming and increases brightness.

Abstract: An improvement in the process for the production of articles from lignocellulosic material and a formaldehyde based resin binder comprising the step of treating the lignocellulosic material prior to combining it with the binder by exposing the lignocellulosic material to an acidic environment.

Abstract: A method is provided for the use of borates in the recausticization of alkali-containing liquors such as those produced in the chemical and semi-chemical pulping of wood and in the oxidation and bleaching of wood pulp. Sodium hydroxide is regenerated from sodium carbonate-containing smelts in such pulp processes by autocausticization through the addition of limited amounts of borate. Autocausticization may be carried out at boron to carbonate molar ratios below 2:1 and at sodium to boron molar ratios exceeding 3:1, resulting in high reaction efficiency. Partial autocausticization using borate may also be combined with conventional lime recausticization for the regeneration of sodium hydroxide from sodium carbonate-containing smelts.

Abstract: A method for selectively delignifying lignocellulosic materials and bleaching of pulp and dyes using a combination of an oxidative enzyme and a metal complex. More specifically, the process involves the oxidation of a transition metal redox complex by a phenol oxidizing enzyme such as laccase or peroxidase to mediate the catalytic delignification of chemical pulp and bleaching of textile dye. This process is unique in that only a catalytic amount of metal complex mediator is required on softwood or hardwood kraft pulp, and that recycling or regeneration of the mediator for further pulp delignification is possible. The redox mediator is characterized in that it contains a transition metal ion coordinated with molecules or ions in such a way that the complexes have a formal redox potential between 0.5 and 1.2 volt measured against a normal hydrogen electrode.

Abstract: A chemical wood pulping process having reduced volatile organic compound emissions includes extracting wood particulates with solvent at a pressure less than 50 psi to reduce naturally-occurring particulate pitch and volatile organic compound content without significant dissolution of lignin and wood cellulosic components. The solvent used is methanol, ethanol, or acetone. This is followed by comingling the extracted wood particulates with a liquor having chemical reactants, not including the solvent used to extract the wood particulates, for solubilizing lignin. Then, allowing the chemical reactants of the liquor to react with lignin contained in the extracted wood particulates under controlled conditions of temperature and pressure for a sufficient time to solubilize and remove lignin. This is followed by producing a wood pulp having individual cellulosic fibers while releasing a reduced amount of VOCs in the wood pulping process.

Abstract: Chemical species (e.g., metaborate, carbonate, hydroxide and sulfide) in a boron-containing alkaline wood pulping liquor sample are determined quantitatively by (i) subjecting a first aliquot portion of the sample to a primary acid titration analysis to derive multiple equivalence points at different respective pH values; (ii) subjecting a second aliquot portion of the sample to an analysis to determine the quantitative presence of boron or sulfide ions therein, and then (iii) determining the quantitative presence in the sample of at least one of the chemical species. Wood pulping parameters may thus be determined on the basis of the quantitative presence of the chemical species to assist in process and/or quality control of the wood pulping operation.

Abstract: Papermaking fibers are treated with certain hydrolytic enzymes, specifically including cellulases, such as truncated endo-glucanases, which have been freed of their cellulose binding domain, to generate aldehyde groups at or near the surface of the fibers. Paper sheets made from the resulting fibers exhibit improved strength characteristics relative to paper sheets made from untreated fibers.

Abstract: A method for bleaching unbleached softwood or hardwood pulps using hydrogen peroxide without added alkali for activation is described. The aqueous hydrogen peroxide solution contains an alkaline earth metal carbonate, preferably magnesium carbonate and can be used at elevated temperatures. Bleached hardwood or softwood mechanical pulps with high brightness, low yellowness (b*) and reduced reversion properties are produced.

Abstract: A process for bleaching high bulk cellulosic fiber and producing a durable elevated curl index includes: (a) concurrently bleaching, heat treating and convolving cellulosic fiber pulp at elevated temperature and pressure at high consistency generally under conditions selected so as to preclude substantial fibrillation and attendant paper strength and fiber bonding development; and (b) recovering the pulp wherein the length weighted curl index of the treated fiber is at least about 20% higher than the length weighted curl index of the fiber prior to the heat treatment and convolving thereof. Preferably, the curl imparted to the fiber persists upon treatment for 30 minutes in a laboratory disintegrator at 3000 rpm at 1% consistency at a temperature of 125° F. Moreover, the curl may be imparted to the fiber in a disk refiner at very short residence times, on the order of several seconds or less.

Abstract: A papermaking process wherein calcium carbonate is included in a pulp suspension. The dissolution of the calcium carbonate in the papermaking system is substantially retarded by the introduction of carbon dioxide to said pulp suspension. The invention also provides processes for the production of paper or board in papermaking systems wherein solid calcium carbonate is present as a filler and/or pigment.

Abstract: A multi-function process is described for the separation of cellulose fibers from the other constituents of lignocellulosic biomass such as found in trees, grasses, agricultural waste, and waste paper with application in the preparation of feedstocks for use in the manufacture of paper, plastics, ethanol, and other chemicals. This process minimizes waste disposal problems since it uses only steam, water, and oxygen at elevated temperature in the range of 180° C. to 240° C. for 1 to 10 minutes plus a small amount of chemical reagents to maintain pH in the range 8 to 13. An energy recuperation function is important to the economic viability of the process.

Abstract: A method for producing paper pulp for use in the making of paper from eucalyptus wood chips. The method comprises inoculating wood chips with white rot fungi, fermenting the wood chips so as to cause a propagation of the fungus through the wood chips and allowing the fungus to modify the lignin, and pulping the degraded wood chips by a kraft process.

Abstract: A process for producing paper materials having improved wet strength. This process involves (a) preparing a suspension of unbleached or semi-bleached chemical or semichemical pulp or pulp from recycled fibers; (b) treating the pulp with a phenol-oxidizing enzyme and a mediator; and (c) de-watering the treated pulp in a paper making machine to remove process water and produce the paper material. Preferably, the paper material is heated after the completion of step (c). By the process of the invention, the wet strength of paper materials can be improved without using wet strength resins which makes the product more easily re-used. Further disclosed is a process for producing corrugated paperboard or corrugated containers.

Abstract: A method and device for bleaching chemical paper pulp or dissolving wood pulp, which has been cooked and delignified without employing chlorine-containing chemicals, comprising a bleaching sequence which comprises optionally a first stage comprising a chelation treatment step; a second stage comprising a first peroxide treatment stage, wherein said first peroxide treatment stage is a delignifying peroxide treatment stage in which the amount of peroxide is less than 12 kilo/bone dry metric tons; a third stage comprising an acidic delignifying treatment stage, following said second stage and including a wash, and a fourth stage comprising a second peroxide treatment stage, following said third stage and including a wash, wherein said second peroxide treatment stage is a bleaching peroxide treatment, in which the amount of peroxide exceeds 3 kilo/bone dry metric tons and exceeds the amount of peroxide employed in said second step.

Abstract: Fiber material and cooking liquor are introduced at the top of the digester and pulp is discharged from the bottom of the digester, via a line in which the pulp is maintained at substantially the same pressure level, to a pressurized wash. More than 50% of the used cooking liquor (black liquor) which is extracted from the system in total is extracted from the wash filtrate of the pressurized wash. At the same time a small portion of the wash filtrate is also to be recirculated to the bottom of the digester as dilution liquid. The pressurized wash is regulated so that a high temperature is maintained in the wash filtrate. The extraction is regulated so that a net co-current flow is established at the bottom of the digester.