JP2005120188A - New cellulose phosphate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new cellulose phosphate and a method for producing the same, which improve the discoloration and yield decrease of the cellulose phosphate. <P>SOLUTION: This method for producing the cellulose phosphate is characterized by reacting regenerated cellulose (A) and/or a cellulose derivative (B), phosphoric acid and/or its anhydride (C), and urea as raw materials in a solvent (D) comprising water and/or an organic solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to the production of novel phosphate esterified cellulose.

  Various methods have been studied for phosphorylating cellulose. Specifically, for example, a method in which cellulose is dissolved in a solution containing phosphoric acid and / or its anhydride and water, and the solution is coagulated and washed in a liquid containing less than 50% by weight of water. Is disclosed (see Patent Documents 1 and 2). However, in these methods, in order to increase the content of phosphorus bonded to cellulose, it is necessary to react in a solvent containing a high concentration of phosphoric acid, and to react cellulose in a good solution state. In addition, it is necessary to increase the reaction temperature. As a result, phosphoric esterified cellulose is colored or has the disadvantage that the yield of phosphoric esterified cellulose decreases due to hydrolysis or the like.

Special table hei 10-504594 Special table 2000-504767

  An object of the present invention is to provide a novel phosphate esterified cellulose and a method for producing the same which have improved the above-described problems of coloring and yield reduction of phosphate esterified cellulose.

  In the prior art, when producing phosphorylated ester cellulose, cellulose such as pulp and refined linter was used as the raw material cellulose. However, the present inventors have used regenerated cellulose (A) and / or cellulose derivative ( It was found that this problem can be solved by reacting phosphoric acid and / or its anhydride (C) with urea in a solvent (D) comprising water and / or an organic solvent using B). I came to the end.

The feature of the present invention is to suppress coloring and decomposition by using regenerated cellulose or a cellulose derivative as a cellulose raw material when producing phosphorylated ester cellulose.

  For this reason, future research must be awaited, but cellulose is generally less reactive to phosphate esterification reactions. This is considered to be caused by the crystallinity of cellulose. Regenerated cellulose and cellulose derivatives generally have higher reactivity due to their lower crystallinity than cellulose. Therefore, higher concentrations of phosphoric acid and higher temperature are required than when cellulose is phosphoric esterified directly. Therefore, it is considered that coloring and decomposition can be suppressed.

  The phosphate esterified cellulose obtained using the regenerated cellulose (A) and / or the cellulose derivative (B) of the present invention as a raw material is more phosphoric than the phosphate esterified cellulose obtained using a conventional dissolving pulp or cellulose as a raw material. The acid content is high, and the yield, coloring degree, and thermal decomposition temperature are excellent. In addition, it has excellent absorption capacity for liquids such as water, salt solution, and oil, at the same time it also has ion-exchange performance and absorption capacity for heavy metals, etc. Therefore, it can be used in a wide variety of industries.

  In the present invention, regenerated cellulose (A) and / or cellulose derivative (B) is used as a raw material. The regenerated cellulose (A) here refers to viscose rayon or cellophane. Viscose rayon uses pulp as a raw material, which is first applied to an alkaline solution to obtain alkali cellulose. Carbon disulfide is added to this to form sodium cellulose xanthate, which is dissolved in dilute caustic soda solution to produce viscose. If this viscose is pulled from the base and spun, viscose rayon is produced. Cellophane is a film obtained by extruding viscose into a coagulation bath through a narrow slit, and is in principle the same as viscose rayon. The regenerated cellulose (A) is preferably pulverized and used in order to efficiently disperse it in the solvent.

  As the cellulose derivative (B), carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, ethyl cellulose, and ethyl hydroxyethyl cellulose can be used. These cellulose derivatives are obtained by reacting a monomer with a hydroxyl group of the cellulose skeleton, but if the degree of substitution between these monomers and the hydroxyl group is too high, the phosphoric acid esterification reaction is suppressed, which is not preferable. The degree of substitution is preferably 0.4 or less.

  The ratio of the regenerated cellulose (A) and the cellulose derivative (B) can be arbitrarily set within the range of (A) / (B) = 0/100 to 100/0. When (A) and (B) are mixed, the reactivity varies greatly depending on the degree of polymerization and the specific surface area. Since (B) is generally more reactive with phosphorylated esters than (A), the phosphoric acid concentration and reaction temperature can be lowered when a large amount of (B) is mixed.

  Examples of phosphoric acid (C) used in the present invention include polyphosphoric acid, orthophosphoric acid, phosphorous acid, and phosphorus oxochloride. Examples of anhydrides include phosphorus pentoxide, which is an anhydride of orthophosphoric acid. Further, these phosphoric acids may be mixed and used.

  The solvent (D) used in the present invention uses water and / or an organic solvent. The solvent is determined in consideration of the reaction process and application of the cellulose raw material to be used and phosphate esterified cellulose. Preferably, water that is easy to handle is used, but in order to efficiently advance the phosphoric esterification reaction, it is preferable to use an organic solvent that swells or dissolves the cellulose raw material.

  As the organic solvent used in the present invention, an alcohol solvent, a ketone solvent, an ester solvent, or a mixture of these solvents can be used. Typical alcohols include, for example, methanol, ethanol, and isopropyl alcohol. Examples of typical ketone solvents include acetone and methyl ethyl ketone. Examples of typical ester solvents include ethyl acetate and methyl formate. Moreover, dimethylformamide, dimethylacetamide, etc. can also be used.

  As an example of the production of phosphate esterified cellulose using a cellulose raw material, 10 to 200 parts by weight of phosphoric acid and 10 to 100 parts of urea are mixed with 10 to 100 parts by weight of a solvent, and then 5 to 200 parts by weight of the cellulose raw material is added. Add and react at 50-120 ° C. In consideration of economical, industrial, and handling during production, 2 to 20 parts of phosphoric acid, 2 to 20 parts of urea, and 5 to 10 parts of cellulose raw material are preferable with respect to 100 parts by weight of the solvent. If the amount of phosphoric acid and urea is less than 2 parts relative to the cellulose raw material, the reaction hardly proceeds, and if it exceeds 20 parts, it does not contribute to the phosphoric acid esterification reaction, which is uneconomical. Further, if the concentration of the cellulose raw material is too high during the reaction, stirring becomes difficult, and a special reactor such as a kneader is required. When the reaction temperature is lower than 50 ° C., the reaction rate of the phosphoric esterification becomes slow, which is not preferable for production. A reaction temperature higher than 120 ° C. is not preferable because the yield of phosphorylated esterified cellulose is lowered or colored. After completion of the reaction, although it varies depending on the physical properties of the obtained phosphate esterified cellulose, it is separated in water or non-water and dried. After drying, pulverization may be performed depending on the application.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
[Example 1]
Into a 2 L 4-necked flask equipped with a stirrer and a condenser for refluxing the solvent, 400 g of a reaction solvent (isopropyl alcohol / water = 1/1 (weight ratio)) is charged and heated to 80 ° C. Next, after 400 g of polyphosphoric acid and 200 g of urea were charged and sufficiently dissolved, 80 g of carboxymethylcellulose (cellulose hydroxyl substitution degree: 0.25, manufactured by Nippon Paper Chemical Co., Ltd.) was added and reacted for 4 hours while stirring. Next, after cooling the reaction solution, 500 mL of methyl alcohol was mixed and centrifuged, and the precipitated phosphate esterified cellulose was taken out. After repeating this operation three times, 300 mL of methyl alcohol was mixed, neutralized with 10% caustic soda, centrifuged, mixed again with methyl alcohol, centrifuged, and the resulting phosphorylated cellulose was obtained. After grinding in a mortar, it was dried at 80 ° C. for 24 hours.
[Example 2]
In a four-necked flask exactly the same as in Example 1, 400 g of a reaction solvent (isopropyl alcohol / water = 1/1 (weight ratio)) is charged and heated to 80 ° C. Next, after 400 g of polyphosphoric acid and 200 g of urea were charged and sufficiently dissolved, 80 g of rayon tape fiber as regenerated cellulose was added and reacted for 4 hours while stirring. Next, after cooling the reaction solution, 500 mL of methyl alcohol was mixed, and after centrifuging, the phosphate esterified cellulose was taken out. After repeating this operation three times, mixed with 300 mL of methyl alcohol, neutralized with 10% caustic soda, centrifuged, mixed with methyl alcohol again, centrifuged, and the resulting phosphorylated cellulose was obtained. After grinding in a mortar, it was dried at 80 ° C. for 24 hours.
[Comparative Example 1]
In a four-necked flask exactly the same as in Example 1, 400 g of a reaction solvent (isopropyl alcohol / water = 1/1 (weight ratio)) is charged and heated to 80 ° C. Next, after 400 g of polyphosphoric acid and 200 g of urea were charged and sufficiently dissolved, 80 g of dissolving pulp (brand: NDPT, Nippon Paper Chemicals Co., Ltd.) was added and reacted for 4 hours while stirring. Next, after cooling the reaction solution, 500 mL of methyl alcohol was mixed, and after centrifuging, the phosphate esterified cellulose was taken out. After repeating this operation three times, mixed with 300 mL of methyl alcohol, neutralized with 10% caustic soda, centrifuged, mixed with methyl alcohol again, centrifuged, and the resulting phosphorylated cellulose was obtained. After grinding in a mortar, it was dried at 80 ° C. for 24 hours.

Using the phosphoric esterified cellulose obtained in Examples 1 and 2 and Comparative Example 1, the phosphorus content, water absorption, heavy metal adsorption amount, and thermal decomposition temperature were measured. The results are shown in Table 1.
[Measurement method]
Phosphoric acid content: 50 mg of the phosphorylated ester cellulose obtained is weighed into a Kjeldahl flask, and 5 mL of sulfuric acid and 2 mL of nitric acid are added to thermally decompose. After completion of the decomposition, the reaction mixture was allowed to cool, and then about 5 mL of ion exchange water was added to generate heat and cooled again, transferred to a 50 mL volumetric flask and made constant with ion exchange water. 2 mL of this sample was weighed into another 50 mL volumetric flask, 25 mL of molybdenum vanadium solution was added, and the volume was made constant with ion-exchanged water. After standing for 30 minutes, the absorbance is measured at a wavelength of 400 nm. Similarly, the concentration of phosphorus was calculated from a calibration curve measured using a standard sample.
-Yield: The weight part of the obtained phosphorylated cellulose was expressed in percentage with respect to 100 parts by weight of the cellulose raw material.
-Degree of coloring: judged visually.
Water absorption: 5 g of cellulose phosphate was immersed in pure water for 1 hour, centrifuged and dehydrated, measured for weight, and calculated from weight after drying at 105 ° C. for 24 hours.
Heavy metal adsorption ^amount: addition of phosphorylated cellulose 5g to 200ppm aqueous 100mL of ^{Pb 2+ · Co 2+ · Zn 2+} , was measured heavy metal concentration in the aqueous solution after 24 hours by atomic absorption spectrophotometry.
-Thermal decomposition temperature: It measured using Seiko Electronics Industry Co., Ltd. TG / DTA22.

Claims (3)

Regenerated cellulose (A) and / or cellulose derivative (B), phosphoric acid and / or its anhydride (C) and urea are reacted in a solvent (D) comprising water and / or an organic solvent. Novel phosphoric esterified cellulose and a method for producing the same. 2. The novel phosphorylated cellulose according to claim 1, wherein the regenerated cellulose (A) is viscose rayon and / or cellophane. 2. The novel one according to claim 1, wherein the cellulose derivative (B) is one or a mixture of two or more selected from the group of carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, cellulose acetate, ethylcellulose, and ethylhydroxyethylcellulose. Phosphate esterified cellulose and method for producing the same.