Treatment of fibres

Abstract

Wool is rendered resistant to shrinkage on washing by treatment with from 0.1 to 10% by weight of a composition obtained by mixing (A) a polydiorganosiloxane having terminal silicon-bonded hydroxyl radicals and (B) an organosilane RSiR'.sub.n X.sub.3-n, in which R is a monovalent radical containing at least two amine groups, R' is alkyl or aryl, X is alkoxy and n is 0 or 1, and/or a partial hydrolysate and condensate of the silane. The applied composition is thereafter cured.

Description

This invention relates to a process for the treatment of keratinous fibres.

It has been proposed to reduce the shrinkage of wool on washing by treatment with various organosilicon compounds. For example in U.K. Pat. Nos. 594,901, 613,267 and 629,329 it is proposed to reduce the normal tendency of wool to shrink by treating the wool with certain alkyl or aryl silanes. In U.K. Pat. No. 746,307 there is disclosed a process for preventing the shrinkage of wool by treating the wool with a composition consisting of a diorganopolysiloxane, in which the organic substituents are alkyl, phenyl or alkenyl, and a siloxane containing silicon-bonded hydrogen atoms.

While the known processes have conferred a degree of shrink resistance on woollen fabrics this effect has not been durable to laundering. There has consequently been a need for a shrink resistant treatment having improved durability to washing and which imparts to the fibres a durable soft handle.

We have now discovered that the above recited advantages of durability of handle and shrink resistance may be realised by treatment of keratinous fibres with certain siloxane compositions.

According to this invention there is provided a process for the treatment of keratinous fibres which comprises applying thereto from 0.1 to 10% by weight, based on the weight of the fibres, of a composition comprising the product obtained by mixing (A) a polydiorganosiloxane having terminal silicon-bonded hydroxyl radicals and a molecular weight of at least 750, at least 50 percent of the organic substituents in the polydiorganosiloxane being methyl radicals, any other substituents being monovalent hydrocarbon radicals having from 2 to 30 carbon atoms and (B) an organosilane of the general formula RSiR'.sub.n X.sub.3.sub.-n wherein R represents a monovalent radical composed of carbon, hydrogen, nitrogen and, optionally, oxygen, which radical contains at least two amine groups and is attached to silicon through a silicon to carbon linkage, R' represents an alkyl radical or an aryl radical, each X represents an alkoxy radical having from 1 to 14 inclusive carbon atoms and n is 0 or 1, and/or a partial hydrolysate and condensate of said organosilane, and thereafter curing the applied composition.

The invention also includes keratinous fibres whenever treated by the said process.

The polydiorganosiloxanes (A) are linear or substantially linear siloxane polymers having terminal silicon-bonded hydroxyl radicals. Such polydiorganosiloxanes have about two, that is from about 1.9 to 2, organic radicals per silicon atom and methods for their preparation are well known in the art. The polydiorganosiloxanes should have an average molecular weight of at least 750 and preferably from 20,000 to 90,000.

At least 50 percent of the silicon-bonded organic substituents in the polydiorganosiloxane are methyl, any other substituents being monovalent hydrocarbon radicals having from 2 to 30 carbon atoms, for example alkyl and cycloalkyl radicals, e.g. ethyl, propyl, butyl, n-octyl, tetradecyl, octadecyl and cyclohexyl, alkenyl radicals e.g. vinyl and allyl and aryl, aralkyl and alkaryl radicals e.g. phenyl, tolyl and benzyl. A small proportion of hydroxyl radicals may be attached to non-terminal silicon atoms in the polydiorganosiloxane. However, such non-terminal hydroxyl radicals should preferably not exceed about 5% of the total substituents in the polydiorganosiloxane. The preferred polydiorganosiloxanes are the polydimethylsiloxanes i.e. those represented by the formula ##SPC1##

in which a is an integer preferably having a value such that the polydiorganosiloxane has a viscosity of from 100 to 50,000 cS at 25.degree.C.

Component (B) of the compositions employed in the process of this invention is an organosilane of the general formula RSiR'.sub.n X.sub.3.sub.-n wherein R, R', X and n are as defined hereinabove or may be a partial hydrolysate and condensate of said organosilane. Such organosilanes are known substances and they may be prepared as described, for example, in U.K. Pat. Nos. 858,445 and 1,017,257. In the general formula of the organosilanes the radical R is composed of carbon, hydrogen, nitrogen and, optionally, oxygen and contains at least two amine (which term includes imine) groups. It is attached to silicon through a silicon to carbon linkage, there being preferably a bridge of at least 3 carbon atoms separating the silicon atom and the nearest nitrogen atom or atoms. Preferably also, R contains less than about 21 carbon atoms and any oxygen is present in carbonyl and/or ether groups. Examples of the operative R substituents are --(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.4 NHCH.sub.2 CH.sub.2 NHCH.sub.3, --CH.sub.2.CH.CH.sub.3 CH.sub.2 NHCH.sub.2 CH.sub.2 NH.sub.2, --(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NHCH.sub.2 CH.sub.2 NH.sub.2, ##SPC2##

and (CH.sub.2).sub.3 NH(CH.sub.2).sub.2 NHCH.sub.2 CH.sub.2 COOCH.sub.3. Each of the X substituents may be an alkoxy radical having from 1 to 14 carbon atoms, preferably from 1 to 4 carbon atoms. Examples of X radicals are methoxy, iso-propoxy, hexoxy and decyloxy. When present R' may be any alkyl or aryl radical, preferably having less than 19 carbon atoms, e.g. methyl, ethyl, propyl, octyl or phenyl. Preferred as component (B) are the organosilanes having the general formula RSiX.sub.3 wherein R represents the --(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2 or the --CH.sub.2 CHCH.sub.3 CH.sub.2 NHCH.sub.2 CH.sub.2 NH.sub.2 radicals and each X represents the methoxy or ethoxy radicals.

In the practice of this invention the product obtained by mixing components (A) and (B) is applied to keratinous fibres. When components (A) and (B) are mixed together at normal or elevated temperatures they react, at least partially. The product applied to the fibres will therefore usually comprise, at least in part, a reaction product of (A) and (B) rather than a simple mixture of these two. The composition may be applied to the keratinous fibres using any suitable application technique, for example by padding or spraying. Most conveniently the composition is applied in the form of a dispersion or solution in a liquid carrier. Preferably the compositions are applied as a solution in an organic solvent. Solvents which may be employed include the hydrocarbons and chlorinated hydrocarbons, for example toluene, xylene, white spirit and perchloroethylene. A particularly convenient method of treating the fibres is by application from an organic solvent solution employing a conventional dry-cleaning machine. When application from an aqueous medium is desired it is preferred to employ as component (B) organosilanes in which X contains 3 or more carbon atoms and to partially react (B) with (A), or with both (A) and (C), prior to emulsification.

The relative proportions of (A) and (B) employed in the preparation of the mixture may vary between fairly wide limits. Preferably from 0.5 to 15 parts by weight of the silane (B) are employed per 100 parts by weight of (A), but proportions of (B) in excess of 15 parts, for example up to 50 parts or more are operative.

Following application of the composition the treated fibres are dried and the deposited composition cured. Drying and curing may be carried out by merely exposing the treated fibres to normal atmospheric temperatures (about 20.degree.C) for periods of from several hours to several days. If desired, however, this step may be expedited by the use of elevated temperatures, e.g. from 60.degree. - 140.degree.C. Curing is believed to be initiated by traces of water. Under normal conditions the moisture present in the atmosphere and/or in the applied composition is sufficient for this purpose. If necessary, however, the water content of the curing environment may be supplemented.

According to a further aspect of this invention we have found that the time and/or temperature required for cure of the applied composition may be significantly reduced if there is incorporated in the applied composition certain silanes or partial hydrolysates thereof. In a preferred method of carrying out this invention therefore the composition applied to the fibres has incorporated therein a third component (C) which is (i) a silane of the formula R".sub.m SiZ.sub.4.sub.-m, where R" is a hydrogen atom or a monovalent hydrocarbon radical or monovalent halogenated hydrocarbon radical, Z is an alkoxy or alkoxy alkoxy radical having from 1 - 4 inclusive carbon atoms and m is 0 or 1 and/or (ii) a partial hydrolysate and condensate of the said silane. Compositions comprising (A), (B) and (C) are novel and are included within the scope of this invention.

In the general formula of the silane (i) R" may be hydrogen atom or a monovalent hydrocarbon radical or halogenated hydrocarbon radical, for example alkyl, e.g. methyl, ethyl, propyl, butyl, hexyl, decyl, octadecyl, alkenyl e.g. vinyl or allyl, aryl, aralkyl or alkaryl e.g. phenyl, tolyl or benzyl, halogenoalkyl e.g. chloromethyl, bromoethyl or 3,3,3-trifluoropropyl and halogenoaryl e.g. chlorophenyl. The radical Z may be for example methoxy, ethoxy, propoxy or methoxyethoxy. Preferably Z is methoxy or ethoxy and R", when present, is methyl. Examples of the silanes (i) and their partial hydrolysis and condensation products (ii) are methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltriethoxysilane, phenyltriethoxysilane, tetraethyl orthosilicate, n-butyl orthosilicate, ethyl polysilicate and siloxanes containing both silicon-bonded methyl radicals and methoxy radicals.

Component (C) is best incorporated into the composition by mixing with components (A) and (B) prior to dispersion or solution. The proportion of (C) employed is not narrowly critical. Preferably it is present in a proportion of from 1 to 20 percent by weight based on the total weight of (A) and (B).

Use of component (C) expedites curing of the applied composition and enables a more consistent improvement in shrink resistance to be obtained. The extent of the advantage obtained will vary somewhat depending on the nature of (C). As an indication, however, the presence of methyltrimethoxysilane in the composition enables significant shrink resistant properties to be obtained after several minutes cure at about 70.degree.C or by exposure to normal atmospheric temperatures for a period of from 4 to 24 hours.

The time and/or temperature required for curing the applied composition may also be reduced by incorporating in the composition a siloxane condensation catalyst. Such catalysts may be employed in place of or in addition to the silane component (C). Substances which function as siloxane condensation catalysts are well known in the art. Particularly suitable catalysts for use in the process of the present invention are the metal organic compounds, for example, the titanium alkoxides and chelates e.g. tetrabutyl titanate, tetra-isopropyl titanate and di-isopropoxytitanium di(ethylactoacetate), and metal carboxylates e.g. stannous octoate, dibutyltin dilaurate, dibutyltin diacetate and lead octoate. The catalysts are employed in conventional catalytic proportions, normally from 0.1 to 5% by weight based on the combined weights of (A) and (B).

The use of siloxane condensation catalysts as described hereinabove can, however, significantly reduce the useful (bath) life of the compositions. In general therefore, the use of the siloxane condensation catalyst is less preferred than the incorporation of the silane (C) as a means of expediting curing.

The process of this invention finds application in the treatment of keratinous fibres to endow such fibres with a resistance to shrinkage on washing and also with a durable soft handle. The fibres may be treated in any form, any example of yarns, knitted or woven fabrics or made up garments. They may be present as the sole fibres or as blends with other types of fibre. Where improved handle of the treated fibres is the primary consideration, this may be achieved by depositing on the fabric as little as 0.1% of its weight of the composition. When a significant level of shrink resistance is required a somewhat higher level of application of the composition, e.g. from about 0.5 to 10%, preferably from 1 to 5%, is more appropriate. The weight of composition applied to the fibres, as referred to herein, means the weight of active ingredients namely (A) and (B), or (A), (B) and (C), deposited on the fibres.

If desired the treated fibres may be endowed with a firmer handle by including in the applied composition a resinous organosiloxane polymer, for example a resinous copolymer of (CH.sub.3).sub.3 SiO.sub.0.5 and SiO.sub.2 groups.

The following examples, in which the parts are expressed by weight, illustrate the invention. The partial condensate of CH.sub.3 Si(OCH.sub.3).sub.3 employed in certain of the examples was prepared by refluxing the silane with aqueous sodium hydroxide solution (0.25% by weight NaOH) for 3 hours. The partial condensate was then recovered after neutralisation and removal of volatiles.

Example 1

A composition was prepared by mixing Polydimethylsiloxane having terminal .tbd.SiOH groups and M.Wt. = 45,000 (3000cS at 25.degree.C) 90 parts (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2 5 parts CH.sub.3 Si(OCH.sub.3).sub.3 5 parts

Three parts by weight of the composition were then dissolved in 97 parts by weight of toluene. This solution was used to treat 3 samples of 1:1 cover factor, knitted 2'28s botany wool fabric by padding at 100% mangle expression. After treatment the samples were allowed to air dry at 22.degree.C for 1 hour and then placed in an air circulating oven at 120.degree.C for 5 minutes.

A square of 20 cm. side was marked out on each of the treated samples employing a template and the samples were then washed in 1.25% by weight phosphate buffer solution (pH7) containing 1 g./litre of sodium dioctyl sulphosucciante. The temperature of the wash water was 40.degree.C and washing was carried out in a domestic automatic washing machine.

After 5 minutes the wash was interrupted and the dimensions of the marked square measured with the fabric in the wet state. The wash was then continued for 6 hours after which time the marked square was measured again.

The area felting shrinkage of the samples was then calculated according to the formula

% Area felting shrinkage (FS) = % width shrinkage (WS) .times. % length shrinkage (LS)

WS .times. LS/100

The width shrinkage and length shrinkage were determined according to the formula

Width or length shrinkage = dimension after 5 minutes - dimension after 6 hours.

The average value of percentage area felting shrinkage for the 3 samples was 0.2%. The value obtained with control samples of untreated wool was 72%.

Example 2

The procedure of Example 1 was repeated except that the fabric samples were of chlorinated wool and washing of the samples was carried out in an International Cubex Machine according to the method of International Wool Secretariat Specification W.S.S. 128, Test Method No. 185 (Superwash specification).

In this case the value of area felting shrinkage obtained was 3.3%.

Example 3

Four compositions, designated A to D, were prepared by mixing:

Polydimethylsiloxane as employed in Example 1. x parts X.sub.3 Si(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2 y parts Partial condensate of CH.sub.3 Si(OCH.sub.3).sub.3 z parts

The values X.sub.3, x, y and z in the composition were as follows:

X.sub.3 x y z ______________________________________ A (OC.sub.2 H.sub.5).sub.3 86.2 12 1.8 B (On--C.sub.4 H.sub.9).sub.3 83.3 15 1.7 C (On--C.sub.6 H.sub.13).sub.3 82.5 16 1.5 D (OCH.sub.3)(On--C.sub.8 H.sub.17).sub.2 82.5 16 1.5 ______________________________________

Three parts of each of the compositions was then dissolved in 97 parts of perchloroethylene and the compositions employed to treat samples of knitted botany wool fabric (2'28s, 1:1 cover factor) by padding at 100% mangle expression. After treatment the samples were allowed to dry and cure at 25.degree.C for 24 hours.

On completion of the 24 hour curing period the shrinkresist properties of the wool samples following washing were measured according to the procedure employed in Example 2. In each case the area felting shrinkage was less than 10%.

Example 4

The procedure of Example 1 was repeated except that the methyl trimethoxysilane component was omitted from the composition and the aminosilane was employed at a level of 10 parts per 90 parts of polydimethylsiloxane. Cure of the applied composition in this case was brought about by exposing the treated fabric to a temperature of about 25.degree.C for 4 days.

The area felting shrinkage for the treated fabrics was measured according to the procedure of Example 2 and a value of 14% obtained.

Example 5

A composition was prepared by mixing:

Polydimethylsiloxane having terminal .tbd.SiOH 88.2 parts groups and M.Wt. = 60,000 (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2 10 parts Partial condensate of CH.sub.3 Si(OCH.sub.3) 1.8 parts

Three parts of the composition were dissolved in perchloroethylene (97 parts) and the solution applied to samples of knitted botany wool (2'28s, 1:1 cover factor) by padding at 100% mangle expression. The samples were then exposed to the air at 25.degree.C for 24 hours and the area felting shrinkage measured after washing according to Example 2. A value of 5% was obtained.

Example 6

Three compositions were prepared according to the following formulation

Polydimethylsiloxane of Example 1 88.2 parts (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2 10 parts Silicate 1.8 parts

In each of the three compositions the silicate component was respectively ethyl polysilicate, tetraethyl orthosilicate, and tetra(n-propyl) orthosilicate.

Three solutions were prepared by dissolving three parts of each of the compositions in perchloroethylene (97 parts) and the compositions then applied to knitted botany wool (2'28s, 1:1 cover factor) by padding at 100% mangle expression. After being allowed to air dry for 24 hours at 22.degree.C the area felting shrinkage of the samples after washing was measured according to the procedure of Example 2. In each case the area felting shrinkage was less than 10%.

Example 7

The procedure of Example 1 was repeated except that the composition was prepared by mixing,

Polydimethylsiloxane as Example 1 95 parts (CH.sub.3 O).sub.2 CH.sub.3 Si(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2 5 parts

The washing period was 3 hours, and curing was carried out for 30 minutes at 120.degree.C. The area felting shrinkage of the treated samples after washing was 1%.

Example 8

Compositions were prepared by mixing,

The compositions were applied to samples of botany wool by padding from 3% solutions in perchloroethylene. The samples were then dried by exposure to the ambient atmosphere (21.degree.C) for 4 hours. Measurement of the area felting shrinkage according to the procedure of Example 2 gave a value of 3.6% for the composition containing silane (a), 1.3% for (b) and 14.1% for (c).

Claims

1. A process for the treatment of keratinous fibres which comprises applying thereto from 0.1 to 10% by weight, based on the weight of the fibres, of a composition comprising the product obtained by mixing (A) a polydiorganosiloxane having terminal silicon-bonded hydroxyl radicals and a molecular weight of at least 750, at least 50 percent of the organic substituents present in the polydiorganosiloxane being methyl radicals, any other radicals being monovalent hydrocarbon radicals having from 2 to 30 carbon atoms, (B) up to 50 parts by weight per 100 parts (A) of an organosilicon compound selected from the group consisting of organosilanes of the general formula RSiR'.sub.n X.sub.3.sub.-n wherein R represents a monovalent radical of less than 21 carbon atoms composed of carbon, hydrogen, nitrogen and, optionally, oxygen, which radical contains at least two amine groups and is attached to silicon through a silicon to carbon linkage, R' represents a radical having less than 19 carbon atoms selected from the group consisting of alkyl radicals and aryl radicals, each X represents an alkoxy radical having from 1 to 14 inclusive carbon atoms and n is 0 or 1, and partial hydrolysate and condensate products of said organosilanes, and (C) in amount from that sufficient to significantly reduce the time and temperature required to cure the composition to 20 parts based on the weight of (A) and (B) of an organosilicon compound selected from the group consisting of (i) silanes of the general formula R".sub.m SiZ.sub.4.sub.-m wherein R" represents a substituent selected from the group consisting of hydrogen atoms, monovalent hydrocarbon radicals having from 1 to 18 carbon atoms and monovalent halogenated hydrocarbon radicals having from 1 to 18 carbon atoms, Z represents a radical selected from the group consisting of alkoxy radicals and alkoxyalkoxy radicals having from 1 to 4 inclusive carbon atoms and m is 0 or 1, and (ii) partial hydrolysates and condensates of

2. A process as claimed in claim 1 wherein (C) is employed in a proportion of from 1 to 20 percent by weight based on the total weight of (A) and

3. A process as claimed in claim 1 wherein (B) is an organosilane having the general formula RSiX.sub.3 in which R is selected from the group consisting of --(CH.sub.2).sub.3 NHCH.sub.2 CH.sub.2 NH.sub.2 and --CH.sub.2 CHCH.sub.3 CH.sub.2 NHCH.sub.2 CH.sub.2 NH.sub.2 radicals and each X is selected from the group consisting of methoxy and ethoxy

4. A process as claimed in claim 3 wherein the composition is applied to

5. A composition comprising the product obtained by mixing (A) a polydiorganosiloxane having terminal silicon-bonded hydroxyl radicals and a molecular weight of at least 750, at least 50 percent of the organic substituents in the polydiorganosiloxane being methyl radicals, any other substituents being monovalent hydrocarbon radicals having from 2 to 30 carbon atoms, (B) an organosilicon compound selected from the group consisting of organosilanes of the general formula RSiR'.sub.n X.sub.3.sub.-n wherein R represents a monovalent radical composed of carbon, hydrogen, nitrogen and, optionally, oxygen, which radical contains at least two amine groups and is attached to silicon through a silicon to carbon linkage, R represents a radical having less than 19 carbon atoms selected from the group consisting of alkyl radicals and aryl radicals, each X represents an alkoxy radical having from 1 to 14 inclusive carbon atoms and n is 0 or 1, and partial hydrolysate and condensate products of said organosilanes, and (C) an organosilicon compound selected from the group consisting of (i) silanes of the general formula R".sub.m SiZ.sub. 4.sub.-m wherein R" represents a substituent selected from the group consisting of hydrogen atoms, monovalent hydrocarbon radicals having from 1 to 18 carbon atoms and monovalent halogenated hydrocarbon radicals having from 1 to 18 carbon atoms, Z represents a radical selected from the group consisting of alkoxy radicals and alkoxyalkoxy radicals having from 1 to 4 inclusive carbon atoms and m is 0 or 1, and (ii) partial hydrolysates and condensates of (i) wherein component (B) is employed in a proportion of from 0.5 to 15 percent by weight based on the weight of (A) and component (C) is employed in a proportion of from 1 to 20 percent by

6. A composition as claimed in claim 5 which also comprises an organic solvent.