FIBROUS CELLULOSE-CONTAINING MATERIAL, FIBROUS CELLULOSE COMPOSITE RESIN, AND METHOD FOR PREPARING FIBROUS CELLULOSE-CONTAINING MATERIAL

Abstract

Fibrous cellulose-containing materials not causing coloring problem when used as resin-reinforcing materials, a preparation method thereof, and fibrous cellulose composite resins without coloring problem. The material contain fibrous cellulose having an average fiber width of 0.1 to 19 μm, and having hydroxyl groups partially/fully substituted with carbamate groups at a rate of 1.0 mmol/g or higher, and the material has a moisture percentage below 18%. The method includes heat treating a cellulose raw material and urea and/or a derivative thereof to substitute part/all of hydroxyl groups in cellulose with carbamate groups, defibrating the raw material to have an average fiber width of 0.1 to 19 μm, and adjusting moisture percentage to below 18% to obtain a fibrous cellulose-containing material, and the heat treating is performed so that the substitution rate is 1.0 mmol/g or higher. The fibrous cellulose composite resin contains the fibrous cellulose-containing material and resin.

Claims

1. A fibrous cellulose-containing material, comprising: fibrous cellulose having an average fiber width of 0.1 to 19 μm, and having hydroxyl groups partially or fully substituted with carbamate groups at a rate of substitution with the carbamate groups of 1.0 mmol/g or higher, wherein the fibrous cellulose-containing material has a moisture percentage of less than 18%.

2. The fibrous cellulose-containing material according to claim 1, further comprising, in the presence of the fibrous cellulose, non-interactive powder that is non-interactive with the fibrous cellulose.

3. The fibrous cellulose-containing material according to claim 1, wherein a lignin content of raw material pulp for the fibrous cellulose is 1% or lower.

4. The fibrous cellulose-containing material according to claim 1, wherein a brightness (JIS P 8148) of raw material pulp for the fibrous cellulose is 50% or higher.

5. The fibrous cellulose-containing material according to claim 1, wherein the fibrous cellulose has a fine fiber percentage of 99% or lower.

6. A fibrous cellulose composite resin comprising the fibrous cellulose-containing material according to claim 1, and a resin.

7. A method for preparing a fibrous cellulose-containing material, comprising: heat treating a cellulose raw material and at least either of urea and a derivative thereof to substitute part or all of hydroxyl groups in cellulose with carbamate groups, defibrating the cellulose raw material to have an average fiber width falling within a range of 0.1 to 19 μm, and adjusting a moisture percentage to less than 18% to obtain a fibrous cellulose-containing material, wherein the heat treating is carried out so that a rate of substitution with the carbamate groups is 1.0 mmol/g or higher.

8. The fibrous cellulose-containing material according to claim 2, wherein a lignin content of raw material pulp for the fibrous cellulose is 1% or lower.

9. The fibrous cellulose-containing material according to claim 2, wherein a brightness (JIS P 8148) of raw material pulp for the fibrous cellulose is 50% or higher.

10. The fibrous cellulose-containing material according to claim 3, wherein a brightness (JIS P 8148) of raw material pulp for the fibrous cellulose is 50% or higher.

11. The fibrous cellulose-containing material according to claim 2, wherein the fibrous cellulose has a fine fiber percentage of 99% or lower.

12. The fibrous cellulose-containing material according to claim 3, wherein the fibrous cellulose has a fine fiber percentage of 99% or lower.

13. The fibrous cellulose-containing material according to claim 4, wherein the fibrous cellulose has a fine fiber percentage of 99% or lower.

14. A fibrous cellulose composite resin comprising the fibrous cellulose-containing material according to claim 2, and a resin.

15. A fibrous cellulose composite resin comprising the fibrous cellulose-containing material according to claim 3, and a resin.

16. A fibrous cellulose composite resin comprising the fibrous cellulose-containing material according to claim 4, and a resin.

17. A fibrous cellulose composite resin comprising the fibrous cellulose-containing material according to claim 5, and a resin.

Description

EXAMPLES

[0215] Next, Examples demonstrating the effects (coloring property, flexural modulus, bending strength) of the moisture percentage of the fibrous cellulose-containing material on the fibrous cellulose composite resin will be discussed.

[0216] First, softwood kraft pulp having a moisture percentage of 10% or lower, an aqueous solution of urea having 10% solid concentration, and various pH adjusting liquids were mixed at a mass ratio in terms of solids of pulp:urea:citric acid=100:50:0.4, and dried at 105° C. Then the resulting mass was subjected to heat treatment at the reaction temperature of 160° C. for the reaction time of 1 hour to obtain carbamate-modified pulp (rate of carbamation at 1.0 mmol/g).

[0217] The carbamate-modified pulp thus obtained was diluted with distilled water, stirred, and dewatered to wash, which was repeated twice.

[0218] The washed carbamate-modified pulp (3% concentration) was made finer using a beater (single disk refiner: SDR) until the fine fiber percentage (percentage of fibers of 0.2 mm or shorter determined by fiber length distribution measurement using FS5) becomes 77% or higher to thereby obtain an aqueous dispersion of carbamated microfiber cellulose (MFC).

[0219] Next, to this aqueous dispersion (3% fiber concentration), polypropylene (PP) powder and maleic anhydride-modified polypropylene (MAPP) powder were added (carbamated MFC:PP powder:MAPP=55.0:17.5:27.5) and mixed into a slurry. This slurry was dried under heating in a drum dryer (140° C., 3 rpm) to obtain a dried product (fibrous cellulose-containing material). Here, at different rotational speed of the drum (2 to 4 rpm), carbamated MFC dried products of different moisture percentages (5 to 20%) were obtained. As the PP powder, NOVATEC PPMA3 pellets manufactured by JAPAN POLYPROPYLENE CORPORATION were powdered (fraction passing 500 μm or smaller sieve, 123 μm in median diameter) and used. The MAPP powder was SCONA 9212F manufactured by BYK.

[0220] For determining the flexural modulus and the bending strength, first a carbamated MFC dried product obtained above was kneaded in a twin-screw kneader (180° C., 200 rpm), and formed into pellets. The pellets were mixed with PP (polypropylene) pellets (carbamated MFC pellets: PP pellets=10:45) so that the carbamated MFC accounted for 10%, kneaded in a twin-screw kneader (180° C., 200 rpm), formed into pellets, and injection-molded to obtain a test piece. The flexural modulus of the test piece was determined in accordance with JIS K 7171: 1994. In the Table, the result is shown as “o” (circle mark) where the flexural modulus of the composite resin was 1.3 times or more the flexural modulus of the resin per se (1.4 Gpa) being 1, whereas the result is shown as “x” (cross mark) where the flexural modulus of the composite resin was less than 1.3 times the flexural modulus of the resin per se (1.4 Gpa) being 1. Further, the bending strength was determined in accordance with JIS K 7171: 1994. In the Table, the result is shown as “o” (circle mark) where the bending strength of the composite resin was 1.1 times or more the bending strength of the resin per se (53.4 Mpa) being 1, whereas the result is shown as “x” (cross mark) where the bending strength of the composite resin was less than 1.1 times the bending strength of the resin per se (53.4 Mpa) being 1.

[0221] For determining the coloring property, the pellets prepared above (MFC:PP:MAPP=10:85:5) were processed into a plate of 6 cm×6 cm×4 mm in thickness, and the plate surface was measured for ISO brightness. The result is shown as “o” (circle mark) where the measured value was 7% or higher, whereas the result is shown as “x” (cross mark) where the measured value was lower than 7%. The ISO brightness was measured using a spectroscopic brightness meter (Spectro Whiteness Colour Meter SC10WT) manufactured by SUGA TEST INSTRUMENTS CO., LTD. This brightness meter makes measurements in accordance with JIS P 8148.

[0222] The results are shown in Table 1.

TABLE-US-00001 TABLE 1 Moisture Flexural Bending percentage modulus strength Brightness % Evaluation Evaluation Evaluation Test Example 1 5.0 ∘ ∘ ∘ Test Example 2 5.3 ∘ ∘ ∘ Test Example 3 5.9 ∘ ∘ ∘ Test Example 4 9.9 ∘ ∘ ∘ Test Example 5 15.4 ∘ ∘ ∘ Test Example 6 15.9 ∘ ∘ ∘ Test Example 7 21.5 ∘ ∘ x

[0223] <Discussion>

[0224] It was revealed that, at a moisture percentage of the fibrous cellulose-containing material of less than 18%, the flexural modulus and the bending strength of the fibrous cellulose composite resin were improved, while the coloring was suppressed. It is also noted that, irrespective of the moisture percentage, the flexural modulus and the bending strength are similarly improved.

INDUSTRIAL APPLICABILITY

[0225] The present invention is applicable as fibrous cellulose-containing material, fibrous cellulose composite resin, and a method for preparing fibrous cellulose-containing material.