Nippon Paper Industries Co., Ltd.

Harima Chemicals, Incorporated

Sony Corporation

Yuko Iijima

Hiroshi Abe

Makoto Sato

Harumi Kawamura

Akira Isogai

Shoichi Miyawaki

Shiho Katsukawa

Koji Kutsuwa

Yoshiharu Kimura

Takao Sezaki

An effluent produced in oxidation of a cellulosic material with an oxidizing agent in the presence of an N-oxyl compound and a bromide and/or iodide is deionized by electrodialysis to an inorganic salt concentration of less than 0.4%, whereby the N-oxyl compound in the effluent is concentrated and recovered. The N-oxyl compound thus recovered can be reused in oxidation of a cellulosic material. Preferably, the effluent is subjected to reduction treatment and ion exchange resin treatment prior to the electrodialysis.

Method for recovery/reuse of N-oxyl compound

There is provided a filled paper containing a coated filler obtained by coating a filler with a acrylamide copolymer (composite PAM) comprising (A) an anionic polysaccharide and (B) a cationic and/or an amphoteric acrylamide copolymer. The composite PAM is obtained, for example, by mixing the component (A) and the component (B). Since the filler is treated with a combination of the components (A) and (B) different from each other in charge properties and structure, suitable coagulation effect can be attained and the coated filler has excellent affinity for pulp slurry. Therefore, even in the case of a highly filled paper, a large paper strengthening effect can be attained by using a small amount of the chemical agent.

Filled paper and method of manufacturing the same

A papermaking additive comprising cellulose nanofibers whose aqueous solution at a concentration of 2% (w/v) has a B-type viscosity (60 rpm, 20&#xb0; C.) of 500 to 7000 mPa&#xb7;s, preferably 500 to 2000 mPa&#xb7;s is used to prepare a paper having improved air resistance and smoothness. This additive is prepared by oxidizing a cellulosic material with an oxidizing agent in the presence of (1) N-oxyl compound(s) and (2) bromide, iodide or a mixture thereof to prepare oxidized cellulose, and finely grinding the oxidized cellulose in a wet condition to convert the oxidized cellulose into nanofibers.

Papermaking additive and paper containing the same

Cellulose nanofibers are produced using a 4-hydroxy TEMPO derivative by treating a cellulosic material with an oxidizing agent in water in the presence of a cellulose oxidation catalyst containing an N-oxyl compound to prepare oxidized cellulos, and microfibrillating the oxidized cellulose.

Processes for producing cellulose nanofibers

Growing community of inventors

Tokyo, Japan

Yuko Iijima