Cellulose microfibers and a method of manufacturing the same

When the cellulose microfibers are used as the dispersion， the cellulose microfibers having extremely high transparency and viscosity of the dispersion are provided. The cellulose fiber is substituted with a carbamate group by introducing a carbamate group while a portion of the hydroxy group of the cellulose fiber is substituted with a predetermined functional group to introduce an ester of phosphoric acid. In addition， about the manufacturing method of a cellulose fine fiber， an additive (A) and the additive (B) which consists of at least any one of urea and a urea derivative are added to a cellulose fiber， and it heats at 100-210 degreeC， and washes and decomposes. The addition amount of the additive (B) is 0.01 to 100 mol with respect to 1 mol of the additive (A). [Problem] To provide cellulose microfibers that， when cellulose microfibers are made into a dispersion， give extremely high transparency and viscosity of the dispersion， and a method for producing the same. [Solution] In the cellulose fibers， an ester of phosphoric acid is introduced by substituting some of the hydroxy groups of the cellulose fibers by a predetermined functional group and a carbamate is introduced by substitution by a carbamate group. In addition， in the method for producing cellulose microfibers， an additive (A) and an additive (B) comprising urea and/or a urea derivative are added to cellulose fibers， heated at 100-210°C， washed， and then defibrated. The amount of additive (B) added is 0.01-100 mol per mol of additive (A). [Problem] To provide cellulose microfibers that， when cellulose microfibers are made into a dispersion， give extremely high transparency and viscosity of the dispersion， and a method for producing the same. [Solution] In the cellulose fibers， an ester of phosphoric acid is introduced by substituting some of the hydroxy groups of the cellulose fibers by a predetermined functional group and a carbamate is introduced by substitution by a carbamate group. In addition， in the method for producing cellulose microfibers， an additive (A) and an additive (B) comprising urea and/or a urea derivative are added to cellulose fibers， heated at 100-210°C， washed， and then defibrated. The amount of additive (B) added is 0.01-100 mol per mol of additive (A).