1. Field of the Invention
The invention relates to a process for the production of a stable, aqueous preparation of compounds which are organosiloxanes having amino groups attached to the silicon atoms for shrink-proofing wool.
2. Description of the Prior Art
It is well known that wool, in the untreated state, shrinks and felts on being washed in aqueous liquor. In order to counteract this shrinkage and felting, chemical treatments have already been recommended in which the structure of the wool is changed, or finishes have been used which contain resin that deposits on the surface of the wool fibers and envelopes the fibers. With both processes, however, products are obtained whose so-called "hand" or aesthetic feel is unpleasant to the consumer.
It has also been recommended that the shrinkage of wool on washing can be reduced by treatment with organosilicon compounds. Such processes are described in British Pat. No. 594,901, 613,267 and 629,329. According to these processes, the wool is treated with certain silanes. A process is described in British Pat. No. 746,307 for preventing the shrinkage of wool whereby the wool fibers are finished with specific silanes. Although a certain degree of shrink-proofing is achieved with this process, the effect is not wash-proof.
In a series of further publications, e.g., German Offenlegungsschriften No. 2,242,297, 2,335,751 and 2,523,270, processes are disclosed for shrink-proofing keratinous fibers by applying organopolysiloxanes, a significant characteristic of these processes being the amino-group content of the compounds. The process according to German Offenlegungsschrift No. 2,242,297 is, for example, characterized by the fact that organopolysiloxanes are used that have units of the general formula EQU R.sub.n SiO.sub.4-n/2
in which
n has an average value of 1.9 to 2.1 and PA1 R is an organic residue, connected to silicon via a silicon-carbon bond, whereby 0.25 to 50% of the R substituents are monovalent residues with fewer than 30 carbon atoms, which contain at a distance of at least 3 carbon atoms from the silicon atom, at least one imino group and at least one primary or secondary amino group --NX.sub.2, in which X is a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, or an aryl group and whereby the remaining R substituents are monovalent hydrocarbon residues, halogenated hydrocarbon residues, carboxyalkyl residues or cyanoalkyl residues with 1 to 30 carbon atoms of which at least 70% consist of monovalent hydrocarbon residues with 1 to 18 carbon atoms. PA1 R is a monovalent group composed of carbon, hydrogen, nitrogen and oxygen, that contains at least two amino groups and is connected to silicon by a silicon-carbon bond, PA1 R' is an alkyl group or an aryl group, PA1 X are alkoxy groups with 1 to 4 carbon atoms inclusive, and PA1 n is zero or 1, and/or contains a partial hydrolysate and condensate of the organo-silane containing product.
From German Offenlegungsschrift No. 2,235,751 a process for treating keratinous fibers is known which is characterized by the fact that the organopolysiloxane composition is obtained by mixing.
(A) a polydiorganosiloxane with terminal hydroxy groups attached to silicon atoms and a molecular weight of at least 750, in which at least 50% of the organic substituents of the polydiorganosiloxane are methyl groups and in which the other substituents are monovalent hydrocarbon groups with 2 to 30 carbon atoms and
(B) an organo silane of the general formula EQU RSiR'.sub.n X.sub.3-n
in which
It is stated in this German Offenlegungsschrift that the two components of the mixture should be reacted if they are to be applied from an aqueous medium. Practical experiments have, however, shown that it is not possible to produce stable, aqueous emulsions from such reaction products. Gel-like reaction products result which cannot be converted into an emulsion. They are, therefore, unsuitable for shrink-proofing wool.
Thus, one of the major disadvantages of these known processes is that the organosilicon compounds must be applied as a dispersion or as a solution in a volatile organic carrier. Organic solvents, such as, hydrocarbons and halogenated hydrocarbons, such as, benzene, hexane and perchloroethylene are mentioned as suitable carriers. In many mills, however, as well as in the case of a later finishing treatment in the home, the use of organic solvents is not possible. In addition, for reasons of environmental protection, it is desirable to avoid the use of organic solvents wherever possible.