阅读说明：本技术 一种纤维素溶液的制备方法 (Preparation method of cellulose solution ) 是由 刘传礼 于 2018-06-08 设计创作，主要内容包括：本发明属于纤维素溶剂技术领域,具体涉及一种纤维素溶液的制备方法。制备方法为：将纤维素浆粕溶解于尿素或硫脲、氢氧化钠以及水组成的混合溶液中；其中,所述纤维素溶液中纤维素浆粕的质量百分浓度为6%,所述尿素或硫脲的质量百分含量为10～12%,所述氢氧化钠的质量百分含量为6～8%。本发明提供了一种纤维素溶液的制备方法,选用尿素或硫脲、碱金属氢氧化物以及水组成的混合溶液体系具有较强的溶解能力；提高了纤维素溶液的浓度,可提高纤维素发泡材料成品的拉伸强度和撕裂强度。该纤维素发泡材料生产成本低、环保压力轻、力学性能良好、吸水率高。(The invention belongs to the technical field of cellulose solvents, and particularly relates to a preparation method of a cellulose solution. The preparation method comprises the following steps: dissolving cellulose pulp in a mixed solution of urea or thiourea, sodium hydroxide and water; the cellulose solution comprises 6% of cellulose pulp, 10-12% of urea or thiourea and 6-8% of sodium hydroxide. The invention provides a preparation method of cellulose solution, wherein a mixed solution system consisting of urea or thiourea, alkali metal hydroxide and water has stronger dissolving capacity; the concentration of the cellulose solution is improved, and the tensile strength and the tearing strength of a finished cellulose foam material product can be improved. The cellulose foaming material has low production cost, light environmental protection pressure, good mechanical property and high water absorption rate.)

1. A method for preparing a cellulose solution, characterized in that: the preparation method comprises the following steps: dissolving cellulose pulp in a mixed solution of urea or thiourea, sodium hydroxide and water; the cellulose solution comprises 6% of cellulose pulp, 10-12% of urea or thiourea and 6-8% of sodium hydroxide.

2. The method for preparing a cellulose solution according to claim 1, characterized in that: the cellulose solution is applied to the preparation of the cellulose foaming material.

3. A method of preparing a cellulose solution according to claim 2, characterized in that: the application method comprises the following steps: adding a pore-forming agent sodium sulfate into the cellulose solution, stirring to obtain mixed slurry, and pouring the mixed slurry into a mold for low-temperature molding; and (3) after low-temperature forming, putting the mixture into a coagulating bath of sulfuric acid and sodium sulfate for dipping, filtering, washing and drying the dipped mixture to obtain the cellulose foaming material.

4. A method of preparing a cellulose solution according to claim 3, characterized in that: the low-temperature forming time is 72 h.

5. A method of preparing a cellulose solution according to claim 3, characterized in that: the solution was immersed in a coagulation bath at 70 ℃ for 1 hour.

6. A method of preparing a cellulose solution according to claim 3, characterized in that: the pore former sodium sulfate was used in an amount of 40% by weight of the cellulose solution.

7. a method of preparing a cellulose solution according to claim 3, characterized in that: the mass percentage of the sulfuric acid in the coagulating bath is 12%, and the concentration of the sodium sulfate is 220 g/L.

8. The method for preparing a cellulose solution according to claim 6, characterized in that: the particle size of the sodium sulfate is less than 5 microns.

Technical Field

The invention belongs to the technical field of cellulose solvents, and particularly relates to a preparation method of a cellulose solution.

Background

The cellulose is used as a natural polymer with the largest content on the earth, has rich and renewable sources, can be decomposed into water, carbon dioxide and inorganic micromolecules by microorganisms in the nature after being discarded, belongs to a biodegradable material, has good biocompatibility and is easy to be derived, and becomes one of the main chemical raw materials in the future.

To date, humans have not fully developed all the potential values of cellulose-based products. Due to the high-density intramolecular and intermolecular hydrogen bond interaction in the cellulose, the cellulose can not be melted, and is difficult to dissolve in some common solvents simply, efficiently, economically and environmentally; various traditional cellulose solvents and dissolving methods also have the defects of environmental pollution, complex process, high cost, harsh conditions and the like, which is another reason why the cellulose is far from being fully utilized at present. For example, more than 90% of the current regenerated cellulose products, such as rayon or cellophane, are produced by the traditional viscose method. The method is not only long in process, but also can generate a large amount of waste water and toxic gas in the production process, which has great influence on human health and also causes serious pollution to the environment. With the increasing severity of industrial pollution and the consequent government regulations, the need for green processes is becoming more and more prominent. The cellulose solvent, especially the non-derivatization solvent capable of physically dissolving cellulose, is a key problem and a core technology for environment-friendly and high-value development and utilization of cellulose, so that research and development of a novel cellulose solvent system are developed, the cellulose is simply, efficiently, economically and environmentally dissolved, and the method has great industrial value and social significance.

The plant fiber is foamed, and the product is widely applied to the fields of green packaging and heat insulation. Therefore, the invention provides a preparation method of the cellulose solution, and the prepared cellulose solution is used for preparing the cellulose foaming material.

Disclosure of Invention

The invention aims to provide a preparation method of a cellulose solution for preparing a fiber foaming material.

The technical scheme adopted for realizing the purpose of the invention is as follows: a preparation method of cellulose solution comprises the following steps: dissolving cellulose pulp in a mixed solution of urea or thiourea, sodium hydroxide and water; the cellulose solution comprises 6% of cellulose pulp, 10-12% of urea or thiourea and 6-8% of sodium hydroxide.

Preferably, the cellulose solution is used in the preparation of cellulose foam.

More preferably, the application method is: adding a pore-forming agent sodium sulfate into the cellulose solution, stirring to obtain mixed slurry, and pouring the mixed slurry into a mold for low-temperature molding; and (3) after low-temperature forming, putting the mixture into a coagulating bath of sulfuric acid and sodium sulfate for dipping, filtering, washing and drying the dipped mixture to obtain the cellulose foaming material.

Preferably, the low temperature forming time is 72 h.

Preferably, the immersion is carried out in a coagulation bath at 70 ℃ for 1 h.

Preferably, the pore former sodium sulfate is used in an amount of 40% by weight of the cellulose solution.

Preferably, the mass percentage content of the sulfuric acid in the coagulation bath is 12%, and the concentration of the sodium sulfate is 220 g/L.

Preferably, the particle size of the sodium sulfate is less than 5 microns.

The technical advantages of the invention are as follows:

The invention provides a preparation method of cellulose solution, wherein a mixed solution system consisting of urea or thiourea, alkali metal hydroxide and water has stronger dissolving capacity; the concentration of the cellulose solution can be improved, and the tensile strength and the tearing strength of a finished cellulose foam material product can be improved. The cellulose foaming material has low production cost, light environmental protection pressure, good mechanical property and high water absorption rate.

In the preparation and application process of the cellulose foaming material, the low-temperature forming is selected, which is beneficial to Na₂SO₄Formation of a crystalline compound. Na added in the invention₂SO₄The activity of hydrogen ions can be inhibited by utilizing the same ion effect of the cellulose and sulfuric acid so as to prevent the cellulose from being excessively degraded.

The invention adopts Na₂SO₄As a pore former of the cellulose foaming material, the cellulose foaming material prepared by the pore former has an open pore structure.

The breaking elongation of the cellulose foam material prepared by the invention reaches more than 2.2 percent, the tensile strength is about 0.25MPa, and the tearing strength is about 0.2 KN.m.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention.