DE1000367B - Process for the production of cellulose ethers which are soluble in water and / or alkali - Google Patents

Description

Process for the preparation of soluble in water and / or alkali Cellulose ethers The invention relates to a process for the production of Cellulose ethers soluble in water and alkali by treating alkali cellulose with one or more alkylating and / or oxalkylating agents. The license plate of the invention is that so-called sieve residues, d. H. a waste product in the production of chemically produced wood pulp after the sulfite or Sulfate process, can be used as the starting material. The sulphate process mentioned also includes soda, which is rarely used today.

The chemical composition of the sieve residues is not yet precise has been researched, but it certainly varies from case to case.

Surprisingly, and despite the fact that sidh the composition the sieve residues can be seen from the one normally used in the production of cellulose ethers pulp used, it was found that the sieve residues excellent for the production of the cellulose ethers mentioned. The received Cellulose ethers naturally have a darker color than those made from cellulose Cellulose ether. These solutions are also darker in color and more turbid than the solutions of common cellulose ethers. However, for many purposes these features have no meaning at all.

Sieve residues from coniferous wood or lukewood wood can be used as the starting material to be used. The main conifers are spruce, fir and pine and the main hardwoods birch, aspen and beech.

The groups to be introduced are especially the methyl, Ethyl and oxethyl group.

The replacement of the normally used pulp with sieve residues does not require any fundamental changes in the manufacturing process, although small Changes, e.g. B. with regard to the concentration of the etherifying agent, sometimes may be appropriate or necessary.

It is generally possible that obtained after the rank of invention Products for the same purposes as the corresponding cellulose ethers to use from the pulp normally used as raw material, except when the cellulose ether must be completely white or its solution must be colorless and clear. Some suitable uses are e.g. B. Adhesives for wallpaper and paper sacks, Binder for graphite in pencil production, core binders and core adhesives for foundries and binders for glass wool and asbestos.

Example The ones used as waste products in sulphite boiling Sieve residues obtained from spruce had a lignin content of 11% and a Extract content of 4.7% when using alcohol as solvent. The viscosity of a copper oxide ammonia solution containing 10/0 cellulose was 50 cP.

Leaves from these sieve residues were treated with 30% sodium hydroxide solution mercerized at room temperature. Damm the immersion liquor was pressed so far that the weight of the alkali cellulose 2.55 times the weight of the original sieve residue fraud.

After a maturing time of 1.5 hours at room temperature, the Alkali cellulose in an amount corresponding to 40 g cellulose together with Ins cm ethylene oxide and a large excess of ethyl chloride placed in an autoclave. The autoclave was then heated to a temperature of 100 ° and this temperature lasted minutes kept constant for a long time. The obtained crude Ethyloxäthylcellulose was by dispersing washed in boiling water.

The water was suctioned off, the cellulose ether was dried and ground. The pure product obtained had a 20% aqueous solution at one temperature of 200 a viscosity of 2200 cP. The viscosity was measured in a rotary viscometer measured according to Brookfield.

Example 2 The same sieve residues as in Example I were in the described way mercerized and pressed; however, the obtained alkali cellulose was Matured at 210 46 hours. The autoclave was filled with alkali cellulose in an amount corresponding to 40 g of cellulose, II ccm of ethylene oxide and a large one Charged excess of ethyl chloride. Ethereal and washing became alike Way as carried out in Example I.

At 200, the ethyloxethyl cellulose obtained had a viscosity in 2% aqueous solution of 35 cP. The determination was made using a Brookfield viscometer.

Example 3 Sieve residues obtained as a waste product from sulphate boiling were mercerized in sheet form with 18.9% sodium hydroxide solution at 200 (degree of pressure 2.17).

The sieve residues had a resin content (dichloroethane extract) of 0.77% and a lignin content of I40 / o. After 60 minutes of preparation (230) After pressing, the material was in an autoclave with in crystal oil (a high-boiling Petrol fraltion) etherified dissolved ethylene oxide. The amount of ethylene oxide used was 2.75 mol per glucose unit in the cellulose, the reaction temperature 45 up to 500 and the reaction time 240 minutes. The crude product obtained was with hydrous Acetone washed free of salt. The Oxäthylcellulose had a 2% aqueous solution Viscosity of I300 CP.

(Brookfield Viscometer).

Example 4 The same sieve residues as in Example 3 were in sheet form mercerized with 20.3% sodium hydroxide solution at 200 (degree of pressure 2, o5). After a The alkali cellulose was pre-matured in an autoclave by means of 60 minutes (240) etherified an excess of ethyl chloride. The reaction temperature was 100 ° and the duration of the project is 210 minutes. The obtained crude product was washed with hot water washed. The viscosity of a 2% solution of ethyl cellulose in 4% sodium hydroxide solution was, similarly as measured in Example 3, 1500 cP. The cellulose ether was in pure water on the other hand almost insoluble.

Claims (1)

PATENT CLAIM: Process for the production of in water and / or Alkali soluble cellulose ethers by treating alkali cellulose with a or more alkylating and / or oxalkylating agents, characterized in that that so-called sieve residues are used as cellulose. Considered publications: German Patent Specifications No. 528 359, 53I oo6, 7I2 666.