Industrial method for preparing regenerated cellulose film

Abstract

The invention discloses an industrial preparation method of regenerated cellulose membranes, wherein, the differences are that celluloses are dissolved in a solvent and stirred fully to prepare cellulose solution which is filtered and de-foamed and put on panels immerging in coagulating bath for flow casting and knifing; the regenerated cellulose membranes are washed by water and then dried; the solvent used is the mixed solution of 8 to 15 percent of sodium hydroxide and 10 to 18 percent of carbamide by weight. The technique is simple; the solvent is pollution-free and the cellulose solution does not contain sulfur; the regenerated cellulose membranes prepared have good mechanical property, lower cost and are easy for industrial production.

Description

technical field [0001] The invention relates to an industrial method for preparing a cellulose film, which belongs to the field of natural polymers, and also belongs to the fields of chemistry, agriculture and environmental engineering. Background technique [0002] Plant cellulose is the most abundant renewable resource on the earth, is an environmentally friendly material, and is expected to become one of the main chemical raw materials in the 21st century. However, cellulose is far from being fully utilized in the chemical industry at present, mainly because the cellulose dissolution process in the existing process is complicated, costly and polluting. At present, more than 90% of the regenerated cellulose products are still produced by the traditional viscose method , cellulose under the action of strong alkali (sodium hydroxide concentration 18%) and CS 2 The reaction produces cellulose xanthate, which becomes cellulose viscose. The cellulose viscose is regenerated in...

AI Technical Summary

Problems solved by technology

However, cellulose is far from being fully utilized in the chemical industry at present, mainly because the cellulose dissolution process in the existing process is complicated, costly and polluting. At present, more than 90% of the regenerated cellulose products are still produced by the traditional viscose method , cellulose under the action of strong alkali (sodium hydroxide concentration 18%) and CS 2 The reaction produces cellulose xanthate, which becomes cellulose viscose

The cellulose viscose is regenerated in a dilute acid solution after being cast to produce a cellulose film; this process releases a large amount of toxic H during the production process 2 S and CS 2 Gas, not only damages human health, but also seriously pollutes the environment

There are problems of environmental pollution and solution recovery in the production of cupro man-made fiber by cupro method

Other organic or inorganic new solvents, such as: dimethyl sulfoxide-nitrogen oxide, aqueous solution, Ca(SCN) 2 and aqueous NaSCN, ZnCl 2 Aqueous solution, chloral-dimethyl sulfoxide-pyridine mixture, LiCl / DMAc are difficult to industrialize due to various reasons

In recent years, a new solvent N-methylmorpholine oxide (NMMO) has emerged and is recognized as the most promising cellulose solvent. The classification of cellulose fibers produced by this method is named "Lyocell", and it is used internationally to prepare A small amount of cellulose fiber products have entered the market, but due to its high price and high spinning temperature, the development of industrial production is slow

6% NaOH / 5% thiourea aqueous solution has been used as a new cellulose solvent to dissolve cellulose and successfully prepare a regenerated cellulose film with excellent strength (Chinese patent: ZL00128162.3), but the solvent system must be 3 under freezing conditions - It takes 5 hours to dissolve cellulose to prepare a transparent concentrated cellulose solution, so it is difficult to realize industrialization