Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From ketone or ketene reactant
Reexamination Certificate
2000-06-01
2001-11-13
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From ketone or ketene reactant
C528S220000, C264S191000, C264S194000, C264S205000, C264S207000, C106S166400, C106S166500, C106S168010, C252S008810, C252S008860
Reexamination Certificate
active
06316582
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of reducing the clogging of nozzles and slits and diminishing the formation of deposits in the spin bath system in the process of making viscose filamentary and film materials by using an alkoxylated polyamine surfactant.
BACKGROUND OF THE INVENTION
When regenerating cellulose material in an acidic spin bath containing zinc sulphate,disturbancies frequently occur due to the presence of clogging material. The origins of the clogging material are different. One and the most important source are solid by-products, i.e. elementary sulphur and zinc sulphide, which are formed when the dissolved xanthogenated celluloses are regenerated to cellulose and carbon disulphide. Other examples of clogging by-products are hemicelluloses and resins derived from the cellulosic raw material itself and transfered to the spin bath where they cause deposits.
One method of reducing these disadvantages is to add cationic surface active compounds to the spinning baths. Thus, in Japanese Patent No. 48006409 it is suggested to add N,N′-polyoxyethylene-N-long chain-alkyl alkylene-diamines and N,N′,N′-polyoxyethylene-N-long chain-alkyl alkylene-triamines into the spin bath as dispersants for sulphur particles which cause blockages in spinning nozzles. The long-chain alkyl group contains from 10 to 20 carbon atoms. The number of oxyethylene groups are from 1 to 8 for each substitution position and their sum is from 2 to 10. However, these additives have a rather limited ability to disperse sulphur, especially when the amounts thereof is high.
In Japanese Patent Application No. 54101916 it is suggested to add polyoxyethylene alkyl mono- and diamide polyalkylene polyamines to further reduce the clogging of nozzles. Examples of the used polyalkylene polyamines are triethylene tetramine and tetraethylene pentamine. The number of carbon numbers in the fatty acids used for preparing the said compounds is preferably from 12 to 22, while the number of groups derived from ethylene oxide in the molecule is from 6 to 12. Although these polyamines have a good dispersing effect they have a serious drawback since they are not stable in hot acid solutions and are hydrolyzed at high temperature in the spin bath. Consequently, after some time their effect is essentially reduced.
The degradation of the additive can be compensated by addition of higher dosages of the additives. However in practice the resulting products of the hydrolysis, i.e. the fatty acids produced especially during reconditioning of the spin bath, enhances the clogging. Together with elementary sulphur and/or zinc sulphide and resins they form black particles, which are very difficult to disperse.
It is therefore an object of the invention to overcome the deficiencies of the prior art.
SUMMARY OF THE INVENTION
The present invention generally relates to the use of an alkoxylated polyamine surfactant having the general formula
RNA&Parenopenst;C
n
H
2n
NA&Parenclosest;
x−1
A (I)
where R represents a hydrogen or an aliphatic group with 1-24 carbon atoms, each A represents hydrogen, an aliphatic group with 1-24 carbon atoms or an H(OC
m
H
2m
)
y
-group, where m is a number from 2-3, y is a number from 1 to 5, n is a number from 2-3, x is 4-8, with the proviso that the number of H(OC
m
H
2m
)
y
-groups are from 1 to x+1, and the total number of carbon atoms in the aliphatic groups is from 8 to 45, as a viscose spin bath additive.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that not only the disturbancies of clogging materials in the spin bath essentially diminished but also the quality of the fibers formed in the spin bath is improved by using an alkoxylated polyamine surfactant having the formula
RNA&Parenopenst;C
n
H
2n
NA&Parenclosest;
x−1
A (I)
where R represents a hydrogen or an aliphatic group with 1-24 carbon atoms, each A represents a hydrogen, an aliphatic group with 1-24 carbon atoms, or H(OC
m
H
2m
)
y
-groups, where m is a number from 2-3, and y is a number from 1 to 5, n is a number from 2-3, x is 4-8, with the proviso that the number of H(OC
m
H
2m
)
y
-groups are from 1 to x+1, and the total number of carbon atoms in the aliphatic groups is from 8 to 45, as a viscose spin bath additive. The alkoxylated polyamine surfactant has an excellent anticlogging effect, since it is a good dispersant and prevent or reduce precipitation in the spin bath. In comparison with the diamines and triamines disclosed in JP 48006409 the anticlogging and dispersing effects are essentially improved. In addition it is very stable in comparison with the amide compounds disclosed in JP Patent Application No. 54101916.
Since the additive keeps the openings in the spinneret free from clogging materials, the filaments and films formed collect less solid particles, whereby the discolouration is reduced and the fiber or film strength improved. In addition the maintainance of the spin bath is also simplyfied. Since the alkoxylated polyamine surfactant has a high stability in ordinary working-up-processes of the spin bath, the spin bath solution can be recirculated after the removal of an excess of the by-products including sodium sulphate formed in the spin bath. The amount of the alkoxylated polyamine surfactant in the spin bath may be varied within wide limits but is normally added in an amount of 0.5-5000 ppm, preferably from 2 to 1000 ppm, to a spin bath containing 5-15% by weight H
2
SO
4
, 15-30% by weight of Na
2
SO
4
and 0-7% by weight of ZnSO
4
.
The alkoxylated polyamine surfactant with formula I preferably contains one or two aliphatic groups, R and A, with a total of 8 to 40 carbon atoms, preferably between 10 and 36 carbon atoms. Preferably R is a hydrocarbon group with 8-24 carbon atoms, and most preferably a hydrocarbon group with 10-22 carbon atoms, while m is 2 and the total number of OC
2
H
4
-units are from 4 to 30.
Most preferred alkoxylated polyamine surfactants of the formula I are those having the formula
RNA&Parenopenst;C
3
H
6
NA&Parenclosest;
x−1
A (II)
where R has the meaning mentioned in formula I, x is 4-6 and A is hydrogen or the group (C
2
H
4
O)
y
H, where y has the meaning mentioned in formula I and the total number of C
2
H
4
O-units is from 4 to 15. These additives are easy to produce and have excellent dispersing ability.
The present invention also relates to a process for regeneration of cellulose from a viscose solution, in which process the viscose solution is brought into contact with a spin bath containing from 0.5 to 5000 ppm of an alkoxylated polyamine surfactant according to formula I. Preferably the alkoxylated polyamine surfactant has the formula II. The spin bath has normally a temperature of from 40° C. to 60° C. and contains in addition to the alkoxylated polyamine surfactant from 5 to 15% by weight of H
2
SO
4
, from 15 to 30% by weight of Na
2
SO
4
and from 0-7% by weight of ZnSO
4
. The cellulose regenerated may have the form of fibers or films or any other conventional shape.
REFERENCES:
patent: 4025353 (1977-05-01), Wahlen
patent: 6068689 (2000-05-01), Bjur et al.
International Search Report, dated Feb. 4, 1999.
Derwent abstract, JP54101916, dated Aug. 10, 1979.
Derwent abstract, JP73006409, dated Sep. 1973.
Bjur Kent
Cassel Anders
Strandberg Margreth
Uneback Ingemar
Akzo Nobel N.V.
Hampton-Hightower P.
Mancini Ralph J.
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