Compositions: coating or plastic – Coating or plastic compositions – Carbohydrate or derivative containing
Patent
1995-10-12
1996-12-10
Brunsman, David
Compositions: coating or plastic
Coating or plastic compositions
Carbohydrate or derivative containing
10616643, 10616701, C08L 122, C08L 124, C08L 102
Patent
active
055826377
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/SE94/00328 filed 14 Apr. 1994.
The present invention relates to a method for improving the processability and the rheological properties of cellulose-based spinning solutions by adding an alkoxylated amine compound. The cellulose content of the spinning solution and/or the flow rate thereof through piping, pumps, filters and spinning nozzles can thus be increased, resulting in improved processability, economy and product properties.
It is known that the rheology of cellulose-based spinning solutions exhibits different phases of state at varying shear forces. In Gotze Chemiefasern, p. 499, there is thus given an example in which a cellulose-based spinning solution exhibits high structural viscosity in rest, while the apparent viscosity changes at varying shear forces. During the passage through a spinning nozzle, the viscosity is reduced by up to about 1/50 of the viscosity in rest. The apparent viscosity can also be increased by increasing the content of cellulose in the spinning solution. The viscosity increase entails many drawbacks. For example, it has been found difficult to use cellulose xanthate solutions having a cellulose content above 10% by weight, if regenerated cellulose fibres having high strength and extension are to be obtained. Other ways of increasing the apparent viscosity is to increase the average polymerisation degree of the cellulose solutions, to change the ratio of cellulose content to liquor content or to lower the temperature of the cellulose solution.
U.S. Pat. Specification No. 4,418,026 proposes adding as solvent to a cellulose acetate a composition containing polyethylene glycol having a molecular weight of 100,000-1,000,000. The purpose is to dispense with the different purification stages which are generally required after the acetate has been formed by acetylation, when using conventional cellulose acetate solvents.
From Swedish Patent Specification 8405800-7 it is known to improve the processability of cellulose-based spinning solutions by adding an ethylene oxide adduct having a molecular weight of 1.1-4.5 million, whereby the flow rate of the cellulose-based spinning solution through the spinning nozzle can be considerably increased. Even if high-molecular-weight ethylene oxide adducts have a good effect and significantly reduce the apparent viscosity of cellulose-based spinning solutions, their use has been hampered by the fact that they are difficult to produce and, hence, involve high costs. There is thus a need for other additives that can replace the high-molecular-weight polyethylene oxide adducts and also contribute to improved reactivity, reduced gel particle formation and improved filterability.
According to the present invention, it has now been found possible to obtain the desired rheological changes in cellulose-based spinning solutions and, for example, at a constant pressure drop over a spinning nozzle having conventional conical holes, to increase the flow rate of the cellulose-based spinning solution by adding an alkoxylate having the formula ##STR2## wherein X is hydrogen, the group R.sub.1 CO-, in which R.sub.1 is a hydrocarbon group having 7-23 carbon atoms or the group -(B).sub.m H, in which B is an alkyleneoxy group having 2-4 carbon atoms and m is 1-7, provided the number of groups of formula R.sub.1 CO is 1 or 2 and the total number of B is 2-20, R is an alkylene group having 2-3 carbon atoms and n is 2-10, preferably 3-7. Preferably, R.sub.1 is a straight or branched, saturated or unsaturated aliphatic group having 9-21 carbon atoms. Of the total number of alkyleneoxy groups, 50-100% are suitably ethyleneoxy groups while the remaining alkyleneoxy groups preferably are propyleneoxy groups or a mixture of propyleneoxy groups and butyleneoxy groups. The total number of alkyleneoxy groups usually is 3-15, preferably consisting entirely of ethyleneoxy groups. The alkoxylate according to formulae I and II may in principle be added at any time during the production of the cellulose-based spinning solution. For example, th
REFERENCES:
patent: 3232779 (1966-01-01), Schonfeldt et al.
patent: 4418026 (1983-11-01), Merrick et al.
patent: 5047197 (1991-09-01), Uneback et al.
International Search Report. PCT/SE94/00328, Dated Aug. 1, 1994.
Soderlund Carl-Axel
Strandberg Margreth
Uneback Ingmar
Akzo Nobel Surface Chemistry AB
Brunsman David
Mancini Ralph J.
Morris Louis A.
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