FIBROUS CELLULOSE COMPOSITE RESIN AND PRODUCTION METHOD THEREFOR

Abstract

A fibrous cellulose composite resin excellent in strength, and a method for producing the same. The fibrous cellulose composite resin includes microfiber cellulose, a resin, and an acid-modified resin, wherein the microfiber cellulose has hydroxyl groups, which are substituted with carbamate groups, and has been washed and defibrated into an average fiber width of 0.1 μm or larger, in which the amount of the byproduct is 10% or less per 100 parts by mass of a carbamate-modified cellulose. The production method includes heat-treating a cellulose raw material and urea to obtain a carbamate-modified cellulose, washing the carbamate-modified cellulose, defibrating the carbamate-modified cellulose to obtain a dispersion of carbamate-modified microfiber cellulose having an average fiber width of 0.1 μm or larger, mixing the dispersion and an acid-modified resin to obtain a material containing carbamate-modified microfiber cellulose, and kneading the material with a resin to obtain a composite resin.

Claims

1. A fibrous cellulose composite resin comprising: fibrous cellulose, a resin, and an acid-modified resin, wherein part or all of the fibrous cellulose is microfiber cellulose, the microfiber cellulose has hydroxyl groups, part or all of which are each substituted with a carbamate group, and has been defibrated into an average fiber width of 0.1 μm or larger, an amount of a byproduct generated in the substitution with a carbamate group is 10% or less per 100 parts by mass of a carbamate-modified cellulose obtained through washing, and the amount of the byproduct is measured by diluting the reaction product obtained by carbamate-modification reaction of urea and the fibrous cellulose with distilled water to have a solid concentration of 1%, mixing and stirring in a mixer, dewatering by means of a No. 2 paper filter and a Buchner funnel, repeating washing operation from the diluting to the dewatering twice, drying the obtained solid material at 105° C. for 6 hours to provide the carbamate-modified cellulose obtained through washing, and calculating amount of the byproduct by subtracting the amount of the carbamate-modified cellulose from the amount of the reaction product obtained by the carbamate-modification reaction.

2. The fibrous cellulose composite resin according to claim 1, wherein a residual amount of urea is 10% or less per 100 parts by mass of the carbamate-modified cellulose.

3. The fibrous cellulose composite resin according to claim 1, wherein a mixing ratio of the acid-modified resin is 1 to 200 parts by mass based on 100 parts by mass of the fibrous cellulose.

4. The fibrous cellulose composite resin according to claim 1, wherein the acid-modified resin is a maleic anhydride-modified resin.

5. A method for producing a fibrous cellulose composite resin comprising: (1) heat-treating a cellulose raw material and at least one of urea and derivatives thereof to obtain a carbamate-modified cellulose, (2) washing the carbamate-modified cellulose, (3) defibrating the carbamate-modified cellulose to obtain a dispersion of carbamate-modified microfiber cellulose having an average fiber width of 0.1 μm or larger, (4) mixing the dispersion of carbamate-modified microfiber cellulose and an acid-modified resin to obtain a material containing carbamate-modified microfiber cellulose, and (5) kneading the material containing carbamate-modified microfiber cellulose with a resin to obtain a fibrous cellulose composite resin.

6. The method for producing a fibrous cellulose composite resin according to claim 5, wherein resin powder is admixed in step (4).

7. The fibrous cellulose composite resin according to claim 2, wherein a mixing ratio of the acid-modified resin is 1 to 200 parts by mass based on 100 parts by mass of the fibrous cellulose.

8. The fibrous cellulose composite resin according to claim 2, wherein the acid-modified resin is a maleic anhydride-modified resin.

9. The fibrous cellulose composite resin according to claim 3, wherein the acid-modified resin is a maleic anhydride-modified resin.

Description

EXAMPLES

[0197] Next, Examples of the present invention will be discussed.

Test Examples 1 to 4

[0198] Softwood kraft pulp with a moisture percentage of 10% or less and an aqueous urea solution with a solid concentration of 10% adjusted with citric acid to pH 7 were mixed at a mass ratio of 10:10 in terms of solid, and dried at 105° C. Then the resulting mass was heat-treated at a reaction temperature of 140° C. for a duration of reaction of 3 hours, to thereby obtain carbamate-modified cellulose.

[0199] The obtained carbamate-modified cellulose was diluted with distilled water and stirred to perform dehydration and washing, which were repeated twice.

[0200] The carbamate-modified cellulose thus washed was beaten in a Niagara beater for 4 hours, to thereby obtain carbamate-modified microfiber cellulose.

[0201] To 500 g of an aqueous dispersion of the carbamate-modified microfiber cellulose at a solid concentration of 2 mass %, 5 g of maleic anhydride-modified polypropylene and 85 g of polypropylene powder were added, and the resulting mass was dried under heating at 105° C. to obtain a material containing carbamate-modified microfiber cellulose. The moisture content of the material containing carbamate-modified microfiber cellulose was less than 10%.

[0202] The material containing carbamate-modified microfiber cellulose thus obtained was kneaded at 180° C. in a twin-screw kneader at 200 rpm to obtain a carbamate-modified microfiber cellulose composite resin. This carbamate-modified microfiber cellulose composite resin was cut in a pelleter into cylinders of 2 mm long and 2 mm in diameter, and injection molded at 180° C. into a cuboid test piece (59 mm long, 9.6 mm wide, and 3.8 mm thick).

[0203] The obtained carbamate-modified microfiber cellulose composite resin was subjected to determination of flexural modulus, fracture strain, and amount of residual urea. The results are shown in Table 1.

[0204] (Flexural Modulus and Fracture Strain)

[0205] Each resin was molded into a bending test piece. This bending test piece was subjected to measurement in accordance with JIS K7171: 2008 and, with reference to the flexural modulus of the resin per se being 1, the flexural modulus of the composite resin (multiple) was evaluated.

Test Example 5

[0206] Test Example 3 was followed, except that the obtained carbamate-modified cellulose was not subjected to dehydration and washing.

[0207] (Amount of Residual Urea)

[0208] A sample of the carbamate-modified cellulose which was subjected to the dehydration and washing, and a sample of the carbamate-modified cellulose which was not subjected to the dehydration and washing, were provided, and 1.5 g of each carbamate-modified cellulose sample was diluted with 300 ml of distilled water, and disintegrated in a mixer for 10 minutes. Then, the obtained aqueous solution was centrifuged at 8500 rpm for 10 minutes to recover the supernatant. The supernatant thus recovered was subjected to quantitative analysis of urea using an ultra high performance liquid chromatograph (model: Nexera X2, manufactured by SHIMADZU CORPORATION), and the amount of the residual urea was calculated from the obtained urea concentration and the amount of the distilled water added.

[0209] (Amount of Carbamate-Modified Cellulose and Amount of Byproducts)

[0210] A reaction product obtained by carbamate-modification reaction of urea and pulp (cellulose) was diluted with distilled water to have a solid concentration of 1%, mixed and stirred in a mixer, and dewatered by means of a No. 2 paper filter and a Buchner funnel. This procedure was repeated twice. The obtained solid material was dried at 105° C. for 6 hours, and the amount of carbamate-modified cellulose was determined. The amount of the byproducts (secondary products) was calculated by subtracting the amount of the carbamate-modified cellulose from the amount of the reaction product obtained by the carbamate-modification reaction.

TABLE-US-00001 TABLE 1 MFC Degree of Amount of average substitution Flexural Fracture residual Amount of NBKP:Urea MFC:MAPP fiber width with carbamate modulus strain urea byproduct Mass ratio Mass ratio — — — — % % Test 10:10 10:1 0.1 μm 0.05 or more 1.3 times 9% or 0 0 Example 1 or more and 0.5 or less or higher higher Test 10:10 10:3 0.1 μm 0.05 or more 1.3 times 9% or 0 0 Example 2 or more and 0.5 or less or higher higher Test 10:10 10:5 0.1 μm 0.05 or more 1.3 times 9% or 0 0 Example 3 or more and 0.5 or less or higher higher Test 10:10  10:10 0.1 μm 0.05 or more 1.3 times 9% or 0 0 Example 4 or more and 0.5 or less or higher higher Test 10:10 10:5 0.1 μm 0.05 or more 1.3 times 9% or 23.5 69.0 Example 5 or more and 0.5 or less or higher higher

INDUSTRIAL APPLICABILITY

[0211] The present invention is applicable as a fibrous cellulose composite resin and a method for producing the same. For example, the fibrous cellulose composite resin may be applicable as interior materials, exterior materials, structural materials, and the like of transport equipment, such as vehicles, trains, vessels, and airplanes; casings, structural materials, internal components, and the like of electronic appliances, such as personal computers, televisions, telephones, and clocks; casings, structural materials, internal components, and the like of mobile communication equipment, such as mobile phones; casings, structural materials, internal components, and the like of mobile music reproduction equipment, video reproduction equipment, printing equipment, copying equipment, sports goods, office equipment, toys, sports goods, and the like; interior materials, exterior materials, structural materials, and the like of buildings, furniture, and the like; business equipment, such as stationaries, and the like; and packages, containers like trays, protection members, partition members, and various others.