An improved market pulp and process for making the same by adding a composite material are described. The composite material includes cellulose nanocrystals, cellulose nanofibers, or another high aspect ratio, high surface area cellulose material (or a starch, or both) and a crosslinking compound that crosslinks a portion of the surface hydroxyl groups to form a 3-D matrix. Adding the composite material to market pulp has been shown to improve the strength of twice-dried paper products, made from such an enhanced market pulp. By crosslinking a portion of the surface hydroxyl groups in the market pulp to form a 3-D matrix, a first drying step may be accomplished without loss of benefits afforded when the market pulp is later re-pulped to make a paper product.

Disclosed herein is a carboxylated cellulose nanofiber and a preparation method thereof. The method includes: mixing choline chloride, citric acid and water at 60-100° C. for 15-60 min to obtain a hydrated multi-carboxylic acid deep eutectic solvent (H-DES); mixing the H-DES and cellulose for hydrolysis-esterification reaction at 120-130° C. for 2-3 h to obtain a carboxylated cellulose; and mixing the carboxylated cellulose and water for nano-fibrillation to obtain the carboxylated cellulose nanofiber.

The present disclosure relates to tissue products comprising crosslinked fibers. The tissue products generally have good formation, such as a Formation Index greater than about 20, strength, such as geometric mean tensile strengths greater than about 700 g/3″ and high bulk, such as sheet bulks greater than about 10 cc/g. Unlike many prior art crosslinked fibers, the crosslinked softwood pulps of the present invention, which are preferably prepared using a glyoxal based crosslinking reagent, are readily dispersible in water and have relatively low degrees of kink and curl. As such, the fibers are well suited for forming wet-laid tissue products and more particularly wet-laid tissue products having improved physical properties, such as improved bulk.

The present invention relates to a method for manufacturing modified cellulose fibers for a moldable cellulose fiber based material, said method comprising: a) providing a chemical or semi-chemical wood pulp comprising cellulose fibers, and optionally subjecting the pulp to alkaline extraction to obtain an alkaline extracted pulp; and b) subjecting the pulp or the alkaline extracted pulp of step a) to a chemical treatment with an alkaline solution and/or an organic solvent to obtain a treated pulp or treated alkaline extracted pulp comprising modified cellulose fibers for a moldable cellulose fiber based material. The invention further relates to a moldable cellulose fiber based material comprising at least 70% by dry weight of modified cellulose fibers obtainable by the method.

The present invention provides aqueous compositions for treating fluff pulp comprising (i) one or more acrylic acid polymers containing phosphinate groups and having a weight average molecular weight of from 1,000 to 6,000 and (ii) from 5 to 50 wt. %, based on the total solids weight of the aqueous compositions, of one or more polyethylene glycols, having a formula weight of from 150 to 7,000, or, preferably, from 200 to 600. The present invention also provides individualized, intrafiber crosslinked cellulosic fibers comprising the cellulosic fiber and, in cured form, the aqueous compositions, as well as methods of making the individualized, intrafiber crosslinked cellulosic fibers.

An object is to optimize a bleaching process in a step of producing phosphorylated cellulose fibers. A pulp comprises cellulose fibers having 0.5 mmol/g or more of phosphoric acid groups or phosphoric acid group-derived substituents, when the pulp is processed into a sheet and four sheets are laminated on one another, the ISO whiteness of the laminate is 82% or more. Moreover, when the pulp is processed into a sheet and four sheets are then laminated on one another, the b* value of the obtained laminate according to the L*a*b* color system is 5.5 or less.

A method for making a specialty fiber by activating pulp in an alkaline aqueous medium, then reacting it a water-soluble, multi-functional reagent able to bridge neighboring cellulose chain within a single fiber. The resultant specialty cellulose fibers have high intrinsic viscosity and may be used to make cellulose ethers, cellulose acetate, and viscose.

A super strong and tough densified wood structure is formed by subjecting a cellulose-based natural wood material to a chemical treatment that partially removes lignin therefrom. The treated wood retains lumina of the natural wood, with cellulose nanofibers of cell walls being aligned. The treated wood is then pressed in a direction crossing the direction in which the lumina extend, such that the lumina collapse and any residual fluid within the wood is removed. As a result, the cell walls become entangled and hydrogen bonds are formed between adjacent cellulose nanofibers, thereby improving the strength and toughness of the wood among other mechanical properties. By further modifying, manipulating, or machining the densified wood, it can be adapted to various applications.

A pulp in accordance with a particular embodiment includes crosslinked cellulose fibers. The pulp can have high brightness, reactivity, and intrinsic viscosity. The pulp, therefore, can be well suited for use as a precursor in the production of low-color, high-viscosity cellulose derivatives. A method in accordance with a particular embodiment of the present technology includes forming a pulp from a cellulosic feedstock, bleaching the pulp, crosslinking cellulose fibers within the pulp while the pulp has a high consistency, and drying the pulp. The bleaching process can reduce a lignin content of the pulp to less than or equal to 0.09% by oven-dried weight of the crosslinked cellulose fibers. Crosslinking the cellulose fibers can include exposing the cellulose fibers to a glycidyl ether crosslinker having two or more glycidyl groups and a molecular weight per epoxide within a range from 140 to 175.

Methods for integrating the production of carboxylated CNCs and carboxylated CNFs from cellulose are provided. Carboxylated CNCs, carboxylated cellulosic solid residues (CSRs) in the form of cellulose fibers (CF) and/or cellulose microfibrils (CMFs), and carboxylated CNFs fabricated using the methods are also provided. The methods are based on the acid hydrolysis of a cellulosic material using weak solid organic acids to produce carboxylated CNCs and CNFs with thermal stabilities that are higher than the thermal stabilities of the cellulosic materials from which they are derived.