According to an example aspect of the present invention, there is provided a method of improving the reactivity and processability of cellulose in order to utilize cheap and easily available raw material and obtain excellent performance for biomaterial manufacturing.

Provided are a method for producing a water-soluble cellulose ether having a low degree of polymerization and enhanced whiteness, and the like. The method includes the steps of: bringing a pulp powder having a multiplication product of less than 0.004 mm.sup.2 which is obtained by multiplying a number-average fiber length by a number-average fiber width, each measured with a Kajaani fiber length analyzer, into contact with an alkali metal hydroxide to obtain an alkali cellulose; reacting the alkali cellulose with an etherifying agent to obtain a crude water-soluble cellulose ether having a high degree of polymerization; purifying the crude water-soluble cellulose ether; drying the purified water-soluble cellulose ether; grinding the dried water-soluble cellulose ether into a water-soluble cellulose ether powder; and depolymerizing the water-soluble cellulose ether powder to obtain the water-soluble cellulose ether having a low degree of polymerization.

Provided are a method for producing a water-soluble cellulose ether having a low degree of polymerization and enhanced whiteness, and the like. The method includes the steps of: bringing a pulp powder having a multiplication product of less than 0.004 mm.sup.2 which is obtained by multiplying a number-average fiber length by a number-average fiber width, each measured with a Kajaani fiber length analyzer, into contact with an alkali metal hydroxide to obtain an alkali cellulose; reacting the alkali cellulose with an etherifying agent to obtain a crude water-soluble cellulose ether having a high degree of polymerization; purifying the crude water-soluble cellulose ether; drying the purified water-soluble cellulose ether; grinding the dried water-soluble cellulose ether into a water-soluble cellulose ether powder; and depolymerizing the water-soluble cellulose ether powder to obtain the water-soluble cellulose ether having a low degree of polymerization.

The invention relates to a method for manufacturing cellulose material, the method comprising introducing cellulose fibers as raw material pulp (1) to a system, adding an alkalizing agent into the system in order to absorb the alkalizing agent into the cellulose fibers (1), adding an anionic agent into the system in order to absorb said agent into the cellulose fibers (1), feeding the cellulose fibers (1) to a sieve plate press (6), performing a reaction between the cellulose fibers and the anionic agent at least partly in the sieve plate press (6) in order to produce anionized cellulose fibers having a degree of substitution between 0.05 and 0.35, wherein the reaction is performed at least partly at a consistency of at least 50%. In addition, the invention relates to a system for manufacturing cellulose material and to fibril cellulose produced from anionized cellulose fibers.

The invention relates to a method for manufacturing cellulose material, the method comprising introducing cellulose fibers as raw material pulp (1) to a system, adding an alkalizing agent into the system in order to absorb the alkalizing agent into the cellulose fibers (1), adding an anionic agent into the system in order to absorb said agent into the cellulose fibers (1), feeding the cellulose fibers (1) to a sieve plate press (6), performing a reaction between the cellulose fibers and the anionic agent at least partly in the sieve plate press (6) in order to produce anionized cellulose fibers having a degree of substitution between 0.05 and 0.35, wherein the reaction is performed at least partly at a consistency of at least 50%. In addition, the invention relates to a system for manufacturing cellulose material and to fibril cellulose produced from anionized cellulose fibers.

The present invention relates to a method of manufacturing ultra-low viscosity hydroxyalkyl cellulose through a partial neutralization method, and the method includes: reacting cellulose with an alkalizing agent to obtain alkalized cellulose; reacting the alkalized cellulose with an etherifying agent to obtain hydroxyalkyl cellulose; performing first neutralization of the hydroxyalkyl cellulose; decomposing the hydroxyalkyl cellulose by using hydrogen peroxide; and performing second neutralization of the hydroxyalkyl cellulose. Through the aforementioned method, ultra-low viscosity hydroxyalkyl cellulose can be manufactured while preventing a process problem, such as swelling, which may occur through the decomposition of an acid treatment.

The present invention relates to a method of manufacturing ultra-low viscosity hydroxyalkyl cellulose through a partial neutralization method, and the method includes: reacting cellulose with an alkalizing agent to obtain alkalized cellulose; reacting the alkalized cellulose with an etherifying agent to obtain hydroxyalkyl cellulose; performing first neutralization of the hydroxyalkyl cellulose; decomposing the hydroxyalkyl cellulose by using hydrogen peroxide; and performing second neutralization of the hydroxyalkyl cellulose. Through the aforementioned method, ultra-low viscosity hydroxyalkyl cellulose can be manufactured while preventing a process problem, such as swelling, which may occur through the decomposition of an acid treatment.

When a combination of pulps having different alkali metal hydroxide solution absorption rates is as a raw material, contact conditions such as a contact temperature and a contact time have to be changed frequently, depending on the absorption rate of pulps currently processed, thereby causing a problem of reduced productivity. For solving the problem, provided is a method for producing alkali cellulose, comprising at least the steps of: bringing two or more types of pulps having different alkali metal hydroxide solution absorption rates into contact with an alkali metal hydroxide solution to obtain a contact product; and draining the contact product, wherein the highest absorption rate is not more than 4.0 times as fast as the lowest absorption rate.