Process for treating non-kerations material with a polythiol resin and an aminoplast and the product obtained
United States Patent [191 Massy et al.  
 [451 Apr. 1, 1975 PROCESS FOR TREATING NON-KERATIONS MATERIAL WITH A POLYTHIOL RESIN AND AN AMINOPLAST AND THE PRODUCT OBTAINED [75] Inventors: Derek James Rowland Massy,  
 Linton; Kenneth Winterbottom, Whittlesford, both of England [73] Assignee: Ciba-Geigy AG, Basle, Switzerland 22 Filed: May 16,1973  
  21 Appl. N0; 360,874  
 Related US. Application Data [63] Continuation of Ser. No. 156.052, June 23, 1971,  
 abandoned.  
 [30] Foreign Application Priority Data July 2, 1970 United Kingdom 3240/70 [52] US. Cl 8/ll5.6, 8/116 R, 8/182, 8/184, 117/1394, 117/1395 A [51] Int. Cl. D06c 29/00 [58] Field of Search 8/115.6, 116 R, 128, 127.6, 8/182,l84;117/141,139.4,139.5 A  
 [56] References Cited UNITED STATES PATENTS 3,706,527 l2/l972 Dobinson et a1 8/l 15.6 X 3,753,649 8/1973 Dobinson et a1 8/115.6 X  
 Primary Examiner Stephen J. Lechert, Jr. Attorney, Agent, or Fi&#39;rm.loseph G. Kolodny; Edward McC. Roberts; Prabodh l. Almaula [57 ABSTRACT 19 Claims, No Drawings PROCESS FOR TREATING NON-KERATIONS MATERIAL WITH A POLYTHIOL RESIN AND AN AMINOPLAST AND THE PRODUCT OBTAINED This is a continuation of application Ser. No. 156,052, filed on June 23, 1971 now abandoned.  
  This invention relates to a process for modifying cellulosic materials in fibrous form, and to materials so treated.  
  It is well known to treat cellulosic materials with aminoplasts. Cellulosic textiles are often treated with these substances to impart dimensional stability, resistance to creasing. or permanent mechanical effects such as pleats and seersucker effects. One drawback is that the tear-strength of the treated textile is often lowered, another is that the treated textile is often harsher. These drawbacks have, to a certain extent, been overcome by incorporating softening agents such as polyethylene emulsions or adducts of ethylene oxide with phenols or amines, but for many purposes these agents are insufficiently effective.  
  It has now been found that, by the use of certain thiolterminated poly(oxyalkylene) substances, preferably in conjunction with particular aminoplasts, cellulosic materials having improved properties, in particular textiles having a fuller, softer handle, can be obtained.  
  Accordingly, the present invention provides a process for modifying cellulosic fibres which comprises 1. treating the fibres, in the absence of keratinous material, with,  
 A. a polythiol having at least two thiol groups per molecule and containing a. radical of a polyhydric alcohol,  
 b. bound to this radical, at least two poly(oxyalkylene) chains,  
 c. bound through oxygen atoms to carbon atoms in the said poly(oxyalkylene) chains, at least two residues selected from the group comprising an acyl residue of a thiol-containing aliphatic carboxylic acid and the residue, after removal of a hydroxyl group, of a thiol-containing aliphatic alcohol,  
 and, optionally,  
 B. an aminoplast which is free from ethylenic unsaturation, and  
 2. curing the polythiol and/or the aminoplast on the fibres.  
  The present invention further provides cellulosic fibrous materials, in the absence of keratinous material, bearing thereon a polythiol as aforesaid in the cured or still curable state.  
  If an aminoplast is used, treatment of the fibres with the aminoplast and the polythiol, and curing the polythiol and aminoplast, can take place in any desired sequence. For example, the fibres may be impregnated with a mixture of the aminoplast and the polythiol, and then the aminoplast and/or the polythiol are cured. Or the fibres may be impregnated first with the polythiol and then with the aminoplast, or vice versa, and then the aminoplast and/or polythiol are cured.- Or the aminoplast can be cured on the fibres, which are then treated with the polythiol and the polythiol is cured.  
  Cellulosic fibres which may be subjected to the process of this invention include cotton, regenerated cellulose, including viscose and cuprammonium rayons, jute, linen, hemp, ramie, sisal, paper, and blends of these cellulosic materials with synthetic fibres. The  
  term cellulosic fibres includes fibres comprised of a substance derived from a cellulose in which some, but not all, of the three available hydroxyl groups per anhydrogluco unit have been chemically modified, eg by 5 acylation, etherification, or cyanoethylation. Thus,  
  methyl cellulose and cellulose monoacetate are included but not, for example, cellulose triacetate. The cellulosic materials are preferably textiles, including yarns, threads, woven, non-woven and knitted fabrics, and garments.  
  Mixtures of two or more cellulosic fibrous materials, and blends with synthetic fibres, may also be treated, but it should be clearly understood that blends of cellulosic fibrous materials with keratinous material are not included within the scope of the present invention.  
  Polythiols used in the process of this invention preferably contain two, three, or up to six thiol groups per molecule. Especially good results have been obtained with those containing two or three thiol groups per molecule.  
  Preferred polythiols are those having a molecular weight between 400 and 10,000 particularly those of formula in which m is an integer of at least 1 and may have different values in each of the p and (q-l) chains,  
 n is a positive integer of at most 2,  
 p is a positive integer of at least 2,  
  q is a positive integer such that (p q) equals at least 3 and at most 7,  
  each alkylene group contains a chain of at least 2 and at most 6 carbon atoms between consecutive oxygen atoms,  
  R represents an aliphatic radical containing at least 2 carbon atoms,  
  and X represents an aliphatic radical containing at least one thiol group.  
  The oxyalkylene units in individual poly(oxyalkylene)chains may be different. They may be substituted, if desired, by e.g., phenyl or chloromethyl groups, 55 There may thus be used the partially or fully esterified compounds of the formula in which R, alkylene, m, p, and q have the meanings previously assigned, and r is a positive integer which may be as high as 18 or even 24.  
 Further preferred are esters of the formula in which alkylene, m, p, and q have the meanings previously assigned,  
 14 is a positive integer of at most 2,  
  and R represents an aliphatic radical having at least 2 and at most 6 carbonatoms.  
 Yet further preferred are esters of formula (-O-olkylen e9 co. C H SH 2] 1 -alkylene&#39;)-0.CO.C 11 SH] and  2 l R o alkylenel; 0.CO. C H SH:l i 3 in which alkylene. m, and u have the meanings previously assigned,  
 p represents2 or 3,  
 p is zero or 1, such that (p, p is 2 or 3,  
 P denotes an integer of at least 3 and at most 6,  
  and R represents an aliphatic hydrocarbon radical having at least 3 and at most 6 carbon atoms.  
  Still further preferred are esters bases on based hexanel ,2,5-tri ol, hexane-1,2,6-triol, ethylene glycol, or propylene glycol, and ethylene oxide and/or propylene oxide, i.e. those of the formulae in (oc n l CH2 (00 H 0.00.0 ll SH,  
 t 21; m u  
  0H (0G H o.co.c rr sn CH (oc a o.co.c i sii (cn cu 3- H (0091 9; 0 co. c n su I 4 CH2 (OC H O.CO.C H SH on (oc t-t on CH2 (OC H O.CO.C H SH 1. 2t m CO u Zu t QQm in which m and u have the meanings previously assigned, and t is an integer of at least 2 and at most 3; and  
  (cu l 2 CH r- (o (CH )mococH su the polythiol having an average molecular weight between 1000 and 7500, where m has the meaning previously assigned. Polythiol esters most preferred for the purposes of the present invention are those obtained from glycerol or propylene glycol, propylene oxide, and thioglycollic.  
 acid, i.e. of formula 0H (oc n 000011 5)! cH (00 11 ococn sa m2 (oc n ococn srr having a molecular weight within the range 1,000 to 5,000, or even 7,500,  
 , CH2 (OC ll l ocociu sn on (00 O Cl-l (OC H OCOCH SH CH CH&#39; 3 CH (oc n OCOCHQSH having a molecular weight within the range 1000 to 7500, where m has the meaning previously assigned. Such esters are commercially available.  
  These thiol-terminated poly(alkylene oxide) esters are readily prepared by the reaction ofa polyhydric alcohol with an alkylene oxide followed by partial or complete esterification of the terminal hydroxylgroups with a mercaptocarboxylic acid.  
  Suitable polyhydric alcohols include ethylene glycol, poly(oxyethylene) glycols, propylene glycol, (poly(oxypropylene) glycols, propane-1,3-diol, poly(epichlorohydrin)s, butane-1,2-diol, butane-1, 3-diol, butane-l ,4-diol, butane-2,3-diol, poly(oxy-1,1- dimethylethylene) glycols, poly(tetrahydrofuran)s, glycerol, 1, l ,l-trimethylolethane, 1,1 ,1- trimethylolpropane, hexane-l,2,5-triol, hexane-1,2,6- triol, pentaerythritol, dipentae&#39;rythritol, mannitol, sorbitol, and adducts of allylene oxides with ammonia or amines, such asdiethanolamine and tetrakis (N-(2- hydroxyethyl) ethylenediamine. Suitable alkylene oxides include ethylene oxide, propylene oxide, tetrahydrofuran and, less preferably, epichlorohydrin. If desired, the polyhydric alcohol may be treated with one alkylene oxide, say propylene oxide, and then tipped with a different alkylene oxide, such as ethylene oxide.  
  The preferred mercaptocarboxylic acids for the esterification are, as already indicated, thioglycollic acid (2-mercaptoacetic acid) and 2-mercaptopropionic acid, but other mercaptomonocarboxylic acids which may be used include mercaptoundecyclic acid and mercaptostearic acid.  
 Preferred thiol-terminated poly(alkylene oxides) for use in the invention include those of formula in which R denotes OH, (Oalkylene),.Ol-I,O.CO.- C H SH, or (O-alkylene),.O.CO.C,,H ,,SH,  
  R, alkylene, m, p, q, and u have the meanings previously assigned,  
  and v is an integer of at least 1 and may have different values in each of the p chains.  
  The oxyalkylene units in the individual poly(oxyalkylene) chains may likewise be different, but are preferably the same, and may be substituted if desired by e.g. phenyl or chloromethyl groups.  
  Preferred among such ethers are those whichare also of formula (-O-alkyl ene-) OCH CHCH SH in which alkylene, R,m,R p, and q have the meanings previously assigned, and further preferred are those of the formula O-alkylene) PCH CHCH SH OCH CHCH in which R t,&#39;m, and 12 have the meanings previously assigned. The ethers in which R denotes Ol-l may be prepared in a known manner by reaction of an alkylene oxide with a polyhydric alcohol, etherification of the hydroxyl groups of the product with epichlorohydrin, and treatment with sodium hydrosulphide to replace the chlorine by a sulphhydryl group( see U.S. Pat. No. 3,258,495, and United Kingdom Specifications 1,076,725 and 1,144,761 In many cases the average &#39;number of thiol groups per molecule is not an integer but, for example, may be 2.6. This is attributable partly to the&#39;replacement of the chlorine atoms by the SH group not going to completion, and partly to sidereactions: for example, the chlorohydrin ether obtained by reaction with epichlorohydrin may also react with epichlorohydrin, so forming an ether which contains two replaceable chlorine atoms per hydroxyl group originally present in the polyhydric alcohol.  
 Ethers of formula in which R t, m, v, and 12 have the meanings previously assigned, are likewise particularly preferred. Ethers in which R denotes -(O-alkylene),-OH may be prepared by treating the product which is obtained from epichlorohydrimthe alkylene oxide and the polyhydric alcohol, first with an alkylene oxide, and then with sodium hydrosulphide see United Kingdom Specification 1,144,761).  
 The most preferred ethers are those of formula where m has the meaning previously assigned, especially such ethers having a molecular weight within the range 700 to 3,500 or up to 7500.  
 drocarbons containing not more than three carbon atoms, such as the dry-cleaning solvents, carbon tetrachloride, trichloroethylene, and perchloroethylene.  
  The amount of the polythiol to be used depends on the effect desired. When the polythiol is used without an aminoplast, then,-for most purposes, from 0.5 to percent by weight calculated on the weight of the material to be treated is preferred. Woven fabrics usually re-&#39; quire from 1 to 10 percent by weight of the polythiol, but rather smaller quantities are usually needed on knitted fabrics, say from 1 to 5 percent by weight. The hand, or handle, of the treated material will, of course, depend on the amount of polythiol employed, and by simple experiment the least amount required to give the desired effect may readily be determined. Further, the composition of, and the construction of, fabrics composed of the fibres also influence the amount of polythiol required. When the polythiol is used in conjunction with an aminoplast, the amount of polythiol will be smaller, say from 0.1 to 3 percent by weight calculated on the weight of material to be treated.  
  The aminoplasts employed contain, per molecule, at least two groups of formula CH OR directly attached to an amidic nitrogen atom or atoms, where R denotes a hydrogen atom, an alkyl group of from one to four carbon atoms, or an acetyl group. Examples of such aminoplasts are the lV-hydroxymethyl,N- alkoxymethyl, and N-acetoxymethyl derivatives of following amides and amide-like substances.  
  1. Urea, thiourea, and the cyclic ureas having the formula in which Y denotes either a group of formula.  
  I Hc cit,  
 HN NH methyl, methoxy, and hydroxy groups, and which may be interrupted by -CO-,-O-, or  
 COH-  
 2-one), dimethylpropyleneurea (5 ,5- dimethylhexahydro-ZH-pyrimid-2-one dimethylhydroxypropyleneurea and dimethylmethoxypropyleneurea (i.e. 4-hydroxyand 4-methoxy-5,5- dimethylhexahydro-2H-pyrimid-2-one), and S-ethyland 5-(2-hydroxyethyl)-triazin-2-one.  
  ll. Carbamates and dicarbamates of aliphatic monohydric and dihydric alcohols containing up to four carbon atoms, e.g. methyl, ethyl, isopropyl, 2- hydroxyethyl, Z-methoxyethyl,Z-hydroxy-n-propyl, and 3-hydroxy-n-propyl carbamates, and ethylene and 1,4- butylene dicarbamates.  
 lll. Melamine and other polyamino-l,3,5-triazines.  
  &#39;If desired, aminoplasts containing both. N- hydroxymethyl and N-alkoxymethyl, or N- hydroxymethyl and N-acetoxymethyl groups, may be used, for example, a hexamethylol melamine in which from 1 to 5 of the methylol groups have been so etherified or esterified.  
  The aminoplast is usually applied as such but, if desired, when a urea-formaldehyde: or melamineformaldehyde product is to be used, it may be formed in situ in a conventional manner from a ureaformaldehyde concentrate or melamine-formaldehyde concentrate and the requisite additional urea or melamine.  
  The aminoplasts employed are, in general, soluble in water and may be applied from aqueous solution; or they may be applied from aqueousemulsions, fromsolutions in the dry-cleaning solvents already mentioned,  
 or from solutions in mixtures of water and a suitable cosolvent, such as methanol.  
 The proportions of the polythiol and the aminoplast can vary widely; usually there will be employed, per  
 thiol group equivalent of the polythiol, from 2 to 50 or even 75, but usually from 5 to 40, N-methylol, N-&#39;  
 alkoxymethyl or N-acetoxymethyl group equivalents of the aminoplast.  
  The desired effects may not be fully obtainable until substantially all the polythiol on the material has cured. At ordinary temperatures this may take from 5 to 10 days or even longer. The curing reaction can, however, be accelerated greatly by the use of a catalyst and generally itis preferred to add the catalyst to the material to be treated&#39;at the same time as the polythiol is applied, although it maybe added before or afterwards if desired. The&#39;curing time can be controlled by selecting an appropriate catalyst and the choice of curing time will depend on the particular application of the process according to the invention.  
  The catalysts may be bases, siccatives, sulphur, sulphur-containing organic compounds, and free-radical catalysts such as azodi-isobutyronitrile peroxides and hydroperoxides, or combinations of these.  
  As organic bases there may be used primary or secondary amines such as the lower alkanolamines, e.g. monoand di-ethanolamine, and lower alkylene polyamines, e.g. ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, propanel,2- and -l.3-diamine, and hexamethylenediamine. As inorganic bases there may be used the water-soluble oxides and hydroxides, e.g. sodium hydroxide, watersoluble, strongly basic salts such as trisodium phosphate, disodium tetraborate, and sodium carbonate, and also ammonia.  
  Sulphur-containing organic compounds which may be used as catalysts include those in which the sulphur atoms are not exclusively present as mercaptan groups, especially mercaptobenzothiazoles and their derivatives, dithiocarbamates, thiuram sulphides, thioureas, disulphides, alkyl xanthogen sulphides and alkyl xan thates.  
  Examples of siccatives are calcium, copper, iron, lead, cerium, and cobalt naphthenates.  
  Examples of suitable peroxides and hydroperoxides are cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, dilauryl peroxide, methyl ethyl ketone peroxide, di-isopropyl peroxydicarbonate, and chlorobenzoyl peroxide.  
  Yet other catalysts are salts of a heavy metal with an acid having an acid strength log pK) below 5, or chelates of a heavy metal, including chelates which are also salts. By heavy metal&#34; is meant one classified as heavy in Langes Handbook of Chemistry, revised 10th Edition, McGraw-Hill Book Co., at pp. 60-61, that is, a metal of group 1B, [1B, lllB, IVB, VB, VIB, VllB, or VlIl, a metal of group IIlA having an atomic number of at least 13, a metal of group IVA having an atomic number of at least 32, or a metal of group VA having an atomic number of at least 51. Preferably the metal is a member of group IB, llB, IVB, VB, VlB, VIlB, or Vlll, particularly the first series of such metals, i.e. titanium, vanadium, chromium, manganese, nickel, and especially iron, cobalt, and copper. Suitable saltforming acids are mineral acids, especially hydrochloric, hydrobromic, nitric, sulphuric, phosphorous, and phosphoric acids, and organic acids such as chloroacetic, fumaric, maleic, oxalic, salicylic, and, more especially citric acid. Suitable chelating agents include those in which the chelating atoms are oxygen and/or nitrogen, for example, 1,2- and l,3-diketones such as acetylacetone, &#39;alkylenediamines such as ethylenediamine, and more particularly, ethylenediaminetetraacetic acid.  
 The amount of catalyst used can vary widely. Ingen- I eral from 0.1 to percent, and usually 1 to 10 percent by weight based on the weight of the polythiol used is required, although much larger quantities can be used.  
  Curing of the polythiol is also assisted by using elevated temperatures and if especially rapid results are required then temperatures in the range to 180C may be used. High humidities also tend to accelerate curing in the presence of catalysts. Curing is also promoted by working at a pH in the range 7.5 to 12.  
  The aminoplast, where one is added, may be cured under the usual conditions, i.e. at room temperature or at elevated temperatures. The mechanism by which the polythiol exerts its effect in conjunction with the aminoplast is not known. It is believed that either the SH group of the mercaptan reacts with the N-methylol groups (present as such or formed in situ from esterified or etherified N-methylol groups), or oxidation of the SH groups occurs, molecules of the polythiol being coupled by means of disulphide bridges. The utility of this invention, however, does not depend on the truth of this belief.  
  In many cases it is desirable to use a catalyst for curing the aminoplast. Catalysts which may be used include conventional materials such as latent acid compounds (which may be metal salts), or mixtures thereof, or certain basic substances. Ammonium salts which are latent acids, developing acidity in the mixture on heating, include ammonium chloride, ammonium dihydrogen phosphate, ammonium sulphate and ammonium thiocyanate. These ammonium salts may be used admixed with metal salts which also have a similar catalytic effect. Amine salts may also be used, eg 2- amino-2-methylpropanol hydrochloride. Among the suitable latent acid metal salts are zinc nitrate, zinc fluoroborate, zinc chloride, zirconium oxychloride, magnesium chloride, magnesium fluoroborate, and magnesium dihydrogen orthophosphate. These catalysts are generally used at concentrations of 0.3 to 5 percent by weight, calculated on the weight of the fibres.  
  There may also be used stronger acids such as hydrochloric or sulphuric acids which may be used as an aqueous solution (say, as 4- to 8- normal solutions) or which may be dissolved in a mixture of water and a solvent which is immiscible or partly miscible with water, andalso acidic gases. Basic substances which may be used include sodium bicarbonate and sodium carbonate. When strong acid catalysts are used, in liquid or gaseous form, heating may not be necessary. In other cases, it may be necessary to heat the treated material, e.g. at a temperature of from 80 to 200C for from 30 seconds to 10 minutes, and preferably at from 120 to 180C for from 2 to 7 minutes.  
  The polythiol, and the aminoplast and catalyst if used, can be applied to the material in conventional ways. For example, where fabric is to be&#39;treated, they may be padded on, or the material may be immersed in a bath. If garments or garment pieces are to be treated then it is convenient to spray them with the agents, and more convenient still to tumble the garments with the agents dissolved in an organic solvent. For the latter method a dry-cleaning machine using a dry-cleaning solvent is particularly useful.  
  A crease-resistant finish may be applied to a cellulosic textile fabric by impregnating with the polythiol,  
 . an aminoplast and a catalyst for curing the aminoplast,  
 drying the textile, usually in a flat configuration, and then curing at least the aminoplast, normally at a high temperature. Compared to fabric treated with aminoplast only, fabric treated in the above manner is considerably softer and has either substantially improved dry crease-resistance with no further loss in tear strength or substantially improved tear strength with no loss in dry crease-recovery.  
  A cellulosic textile fabric having good wet creaserecovery properties may be obtained by impregnating the fabric in an aqueous medium with an aminoplast (such as methylolated dihydroxyethylene urea) and a strong acid catalyst (e.g. hydrochloric acid) for curing the aminoplast, keeping the fabric wet and in an uncreased state (e.g. for 16-24 hours), rinsing the fabric if desired, neutralising the catalyst, drying the fabric if necessary, and treating with the polythiol (with an amine or other catalyst if necessary). Material aftertreated with the polythiol has much better &#39;wet creaserecovery than, and equal tear strength to, fabric treated with aminoplast alone. Cellulosic textile fabrics having both wet and dry crease-recovery may be obtained by similar treatment, and curing the aminoplast while the fabric is moist. By wet we mean having a water content of more than 20 percent by weight, and by moist we mean having a water content of from to percent by weight, both calculatedon the weight of the bonedry fabric.  
  A durablypressed cellulosic garment may be made by treating a cellulosic fabric in piece form with the polythiol (say, as an aqueous emulsion or a solution in an organic solvent), an aminoplast, and a catalyst for the aminoplast, and drying the impregnated fabric, fashioning the sensitised fabric into a garment, inserting any requisite creases or pleats and curing the aminoplast at elevated temperature, e.g. in an oven. Compared with garments treated with aminoplast only, the garment is much softer t0 the touch and has a much better balance of crease-recovery and strength.  
 Thiol C Thiol C denotes a poly (2-hydroxy-3-mercaptopropyl) ether prepared from a glycerol-propylene oxide adduct having an average molecular weight of 4,800, epichlorohydrin, and sodium hydrosulphide. It had a mercaptan content of 0.32 equiv./kg, corresponding to 2.6 SH groups per average molecule.  
 Thiols D-L These Thiols were made in a similar manner to Thiol A. Their compositions are given in the following Table.  
  Polyol Esterifying Mercaptan Mercaptan Thiol Alcohol Alkylene oxide M.W. acid Functionality content (Theoretical) eqjkg D Glycerol Propylene oxide 3000 Thioglycollic 3 0.72 E Glycerol Propylene oxide 6200 Thioglycollic 3 0.30 F Glycerol Propylene oxide 700 Thioglycollic 3 2.9 G Glycerol Propylene oxide 4000 Thioglycollic 2 0.41 H Pentaerythritol Propylene oxide 2000 Thioglycollic 4 1.22 l 1,2,6-Hexane-triol Propylene oxide 1500 Thioglycollic 3 1.63 J Glycerol Propylene oxide 4000 2-Mercapto- 3 0.6  
  propionic K Butane-1.4-diol Tetrahydrofuran 1000 Thioglycollic 2 1.66 L Glycerol Propylene oxide 1000 3-Mercapto- 3 2.3  
 propionic Thiol G is a partial cster.  
 The compositions used in the processof this mven- Thiol M tion, viz. those containing a polythiol as aforesaid, as an aqueous dispersion or emulsion, or as a solution in an organic solvent, and optionally a catalyst and an amino plast, may also contain antisoiling, antistatic, bacteriostatic, rotproofing, flameproofing, and wetting agents. They may also contain water-repellents such as paraffin wax, and fluorescent whitening agents.  
  The following Examples illustrate the invention. Unless otherwise specified, partsand percentages are by weight. The thiols used were prepared as follows:  
 Thiol A A mixture of 800 g (0.2 g-mol.) of a polyoxypropylene triol having an average molecular weight of 4,000 and made from glycerol and propylene oxide, (Polyol A), 55.2 g (0.6g-mol.) of thioglycollic acid, 5 g of toluene-p-sulphonic. acid, and 350 ml of toluene, was heated to reflux with stirring for 4 hours in an atmosphere of nitrogen. Water 10.8 ml, 0.6 g-mol.) formed during the reaction was removed as its azeotrope with toluene. The mixture was cooled and washed with water, and the organic layer was separated. On removing under vacuum the solvent from the organic layer there remained 793 g (94 percent of the theoretical yield) of the desired tris(thioglycollate), (Thiol A), having a mercaptan content of 0.59 equiv./kg.  
 Thiol B A mixture of polyoxypropylene glycol (1000 g) having an average molecular weight of 2000 (0.5 g-mol.) thioglycollic acid (92 g, 1 g-mol.), toluene-p-sulphonic acid (5 g), and perchloroethylene (750 ml), was heated Thiol M was prepared in a similar manner to Thiol C.  
 Emulsion A Thiol A 500 g Emulsifying agent I 50 g water 450 g The components were mixed at room temperature with a Silverson mixer until a uniform emulsion resulted. Emulsifying agent 1 denotes an adduct of a mixture of C and C aliphatic primary amines (1 mol.) and ethylene oxide mols).  
 Emulsions B &amp; C  
  These were prepared in the same manner as Emulsion A, but substituting Thiols B &amp; C for Thiol A.  
 Emulsion D Thiol D 500 g Emulsifying agent 1 50 g sodium carhoxymethylcellulose 5 g water 445 g The components were emulsified as before.  
 Emulsions E-L EXAMPLE 1 Samples of a bleached cotton poplin (108 g per square metre) were padded with Liquors l-4 so that the take-up was 70 percent. The samples were dried for minutes at 70C on tenter frames to their original dimensions and then the compositions were cured. The curing conditions, and measurements of certain properties of the treated samples, are given in Table l.  
 Liquors 14 had the following compositions:  
 Liquor l Aminoplast A 60 g/litre MgCl .6H ,O 2O g/litre in water Aminoplast A is a co-condensate of a methylated hexamethylol melamine containing 4.5 methoxymethyl groups per molecule and dimethylol ethyleneurea.  
 Liquors 2-4 Liquors 2-4 were the same as Liquor l, but contained in addition 30 g per litre of Emulsions A-C respectively.  
  In this, and the following Examples, the dry crease angles of the treated samples were measured by the Monsanto method, twelve specimens (six folded warpwise, six folded weftwise) being used in each test, the specimens were creased under a 2 kg load for 3 minutes and allowed to recover, suspended over a wire, for 3 minutes before the crease angles were measured. The yalues given in the Tables are the average of the six obtained by adding the warpwise value to the corresponding weftwise value and dividing by two. Tear strengths Liquor 1 Thiol C EXAMPLE 2 Samples of the bleached cotton poplin used in Example 1 were padded with Liquor 1 so that the take-up was percent, and dried for 10 minutes at 70C on tenter frames to their original dimensions. The samples were heated for 5 minutes at C to cure the aminoplast. Next, some of these samples were padded with a 0.7 percent solution of a thiol in perchloroethylene, the pick-up of the thiol being 1 percent, and then they were dried as before and heated for 3 /2 minutes at C. The crease angle and tear strengths were measured and they are shown in Table 11.  
 Table I1 Treated with Crease angle Tear strength &#39;(g) Untreated Liquor 1 only Liquor l Thiol A Liquor 1 Thiol B Liquor l Thiol C EXAMPLE 3 Poplin samples were padded with a 0.7 percent solution of the thiol in perchloroethylene to 1 percent pickup of the thiol. The samples were dried for 10 minutes at 70C on tenter frames, heated for 3 /2 minutes at 160C, then treated with Liquor l to 70 percent pickup. The samples were dried in the same manner as before, and cured for 5 minutes at 145C. Measurements of the tear strength and crease angle are given in Table 111.  
 Table III Treated with Crease angle Tear strength (g) Untreated 49 528 Liquor 1 only 99 208 Liquor 1 Thiol A 1 19 228 Liquor 1 Thiol B 116 320 131 352 EXAMPLE 4 In order to ascertain the machine-washability .of cotton poplin treated in accordance with the present invention, samples were padded to 70 percent pick-up with Liquors 1 and 2. After curing, the handle of the material was noted, and the crease angle and tear strength were measured. The samples were then washed three times, with intermediate tumble drying, in an English Electric Reversomatic washing machine set on programme 1 (90C wash) using an aqueous solution containing 2 g/litre soap and 0.8 g/litre soda ash. The crease angle and tear strength were again measured: the results are given in Table IV.  
 Table IV Cure Handle Crease angle Tear strength (g) Liquor Time Temp. Original Washed Original Washed Original Washed (mins) (&#34;C) l 5 14(1 harsh soft 92 73 240 256 2 5 140 soft. soft, 1 16 82 320 256 silky silky Z 3 A 160 soft, soft, 1 24 97 256 272 silky silky EXA E 5 Softening Agent A is a commercially-available prod- Aqueous liquors 5 and 6 were prepared containing 1 the following ingredients, expressed in grams per litre of water:  
 Liquor 5 Liquor 6 Aminoplast A 60 60 Mgcl bH o 20 20 Emulsion A 30 60 Samples of bleached cotton poplin were padded with the above liquors, and also, for comparative purposes, with Liquor 1, so that the uptake was 70 percent. The samples were dried for minutes at 60C on tenter frames, then cured for 3 /2 minutes at 160C. The crease angles and tear strengths were measured, the samples were then washed three times as described in Example 4, and the tear strengths and crease angles were measured again. Table V shows the results obtained.  
 Table V Original Washed Liquor Crease Tear Crease Tear angle strength angle strength lg) (g) EXAMPLE 6 In order to compare the effects of the compositions containing an aminoplast and a polythiol with compositions containing an aminoplast and a conventional softening agent (Softening Agent A) samples of a cotton poplin were treated to 64 percent uptake with the following aqueous liquors:  
 Liquor 7 s 9 10 11 Emulsion A 1O 30 Softening Agent A 10 30 MgCl .6H O 15 15 15 15 15 Aminoplast B 150 150 150 150 150 These figures refer to grams per litre.  
  Aminoplast B is a 50 percent aqueous solution containing equimolar amounts of the pentamethyl ether of hexamethylol melamine and bis(N-hydroxymethyl) ethyleneurea.  
 not sold for use with aminoplasts. V  
  The samples were dried at 110C for 1 minute and cured at 150C for 5 minutes. They were then stored at room temperature. After 1 day, some of the samples were washed in a Hoovermatic washing machine for minutes at 95C with a solution containing soap flakes (5 g per litre) and sodium carbonate (2 g per litre), and then tested. The remaining samples were tested after 5 days storage at room temperature.  
 The results are given in Table VI.  
 Table VI Original Washed Liquor Crease Tear Crease Tear angle strength angle strength From this Table it may be seen that, by using the thiol, a greatly improved crease angle is obtained for a given tear strength, compared to that obtained using the conventional softening agent.  
 EXAMPLE 7 Bleached cotton poplin was padded with a solution of Thiol A in perchloroethylene to 1 percent pick-up of the thiol. The samples were dried for 10 minutes at 60C and kept at room temperature for 24 hours. They were then treated with an aqueous solution containing an aminoplast and 4 g per litre of ammonium sulphate to percent uptake of solution, dried for 10 minutes at 60C, and cured for 3% minutes at C. The  
 crease angles and tear strengths were measured, and are reported in Table V11. Comparative figures for poplin which had not been treated with Thiol A are also Aminoplast C is a 50 percent aqueous solution of bis(N-hydroxymethyl) dihydroxyethyleneurea.  
  Aminoplast D is a 75 percent aqueous solution of a methylated methylolmelamine. containing on average three N-methoxymethyl and two N-hydroxymethyl groups per molecule.  
  Aminoplast E is the pentamethyl ether of hexamethylolmelamine.  
 EXAMPLE 8 Bleached cotton poplin was padded to 70 percent uptake with the following aqueous liquors: (concentration in g per litre) Liquor 12 13 l4 l Emulsion A 30 3O Aminoplast C 120 120 Aminoplast D 100 100 (NH .SO 4 4 4 4 The samples were dried for minutes at 60C, then cured for 3 /2 minutes at 160C. The crease angles and tear strengths were measured, and the results are given a Bleached cotton poplin was padded to 70 percent uptake with Liquors l4 and 15 as described in Example 8, or with an aqueous liquor (Liquor 16) containing 90 g per litre of Aminoplast E and 4 g per litre of ammonium sulphate, dried for 10 minutes at 60C, and cured for 3 /2 minutes at 160C. Some samples were then treated with a solution of Thiol A in perchloroethylene to give 1 percent pick-up of the thiol. After being dried for 10 minutes at 60C, the samples were cured for 24 hours at room temperature, and the crease angles and &#39;tear strengths were measured, the results being reported in Table 1X.  
  An impregnation liquor, comprising 0.2 ml of Emulsion H, 0.2 ml of a 1 percent aqueous solution of monoethanolamine, and 199.6 ml of water, was heated to 60C and a 10 g hank of scoured cellulose diacetate continuous filament yarn was immersed in the liquor, which was kept at 60C for 30 minutes, the yarn being moved continuously in the liquor. The hank was removed, spun in a spin dryer, and dried at C. Comparison with untreated yarn showed that a pleasing softening effect had been imparted to the yarn treated in accordance with the process of this invention.  
 EXAMPLE 11 Samples of a bleached cotton poplin (108 g per sq. metre) were padded with Liquors 17-21 so that the uptake was 70 percent. The compositions of the liquors, expressed in grams per litre of water, were as follows:  
 Liquor l7 l8 19 20 21 22 Aminoplast B 120 120 120 120 120 MgCl .6H O l8 18 18 18 18 18 Emulsion H 20 Emulsion D 20 Emulsion E 2 Emulsion F 20 Emulsion 1 20 The samples were dried for 10 minutes at 70C on tenter frames to their original dimensions and then cured by heating at C for 3 /2 minutes. The crease angles and tear strengths of the patterns were measured. The samples were washed 5 times in an English Electric Reversomatic washing machine set on programme 2 (60C wash) using an aqueous solution containing 2g/l soap and 0.8g/1 soda ash, and then tumbledried. The crease angle and tear strength were again measured: the results are given in Table X.  
  Tests also showed that the thiol did not interfere with the non-chlorine retentive properties of the resin.  
 EXAMPLE 12 Samples of a bleached cotton poplin (tear strength 792g) were padded with Liquor l to 70 percent expression, dried on tenter frames to their original dimensions, and cured by heating for 3 /2 minutes at 160C. Next, some of the samples were padded with a 1.45 percent solution of the Thiol or Polyol A in trichloroethylene to 138 percent pick-up. The trichloroethylene solutions also contained 0.029 percent of diethylentriamine as curing catalyst. The patterns were dried at 70C on tenter frames to their original dimensions and were then allowed to cure at room temperature for &#39;1 week. The crease angle and tear strength were measured and are recorded in Table XI.  
 TABLE XI Treated with Crease angle Tear strength (g) Untreated 46 792 Liquor 1 only 7 108 2111 Liquor l Thiol A 121 Z52 Liquor l Thiol G 124 304 Liquor 1 Polyul A 106 312 This example illustrates that treatment with Polyol A improves only the tear strength whereas that with the thiols improves both the crease angle and the tear strength.  
 EXAMPLE 13 Cotton poplin samples were padded with 1.45 percent solution of Thiol A in trichloroethylene to 138 percent pick up. In some cases the solutions also contained curing catalysts. The patterns were dried at 70C to their original dimensions on tenter frames and they were then kept at room temperature for 1 week to allow the thiol to cure. The samples were then treated with Liquor 1 to 70 percent pick-up; dried at 70C to their original dimensions, and finally cured by heating for 3 /2 minutes at 160C. Some samples were washed three times as described in Example 1 l. Crease angles and tear strength measurements of the treated patterns are recorded in Table XII.  
 aminoplastnNext, some of these samples were padded with a 1.27 percent solution of a thiol and 0.0254 percent of diethylenetriamine in trichloroethylene, the  
 . pick-up of the thiol being 2 percent. They were dried as before, and left at room temperature for 4 days. The crease angles and tear strength were measured, as shown in Table XIVP I Poplin samples were padded with a 1.46 percent solution of the thiol or Polyol A in trichloroethylene to 2 percent pick-up of thiol or Polyol A. The samples were dried for 10 minutes at 70C at their original dimensions on tenter frames. They were then treated with Liquor l to 70 percent expression, dried as before, and cured for 3 /2 minutes at 160C. Some samples were TABLE XII Treated with (7( catalyst Crease angle Tear strength (g) (on weight of cotton) Un- Washed Unwashed washed washed Untreated 46 792 Liquor 1 only 108 98 210 204 Thiol A Liquor 1 121 110 268 328 Thiol A Liquor 1 0.17: Copper naphthenate(87rCu) 132 1 17 208 268 Thiol A Liquor 1 0.2% Diisopropyl xanthogen disulphide 128 1 18 248 280 EXAMPLE l4 washedthree times by the procedure described in Ex- A 50:50 cotton-polyester plain weave fabric was padded with one of Liquors 23-25 to 70 percent pick-up, dried at its original dimensions on tenter frames at 60C, and finally heated for 10 minutes at 170C. The crease angles and tear strength were measured and are recorded in Table XIII, as are the compositions of the liquors.  
 TABLE x111 Liquor Untreated 23 24 25 Aminoplast C (g/l) 150 150 150 MgCl .6H O(g/l) 20 20 20 Emulsion 0 (g/l) Emulsion H (g/l) 30 Crease angle 94 117 122 128 Tear strength (g) 1344 1320 1376 1368 EXAMPLE 15 Samples of the bleached cotton poplin used in Example 1 l were padded with liquor 1 to 70 percent expression, dried on tenter frames to their original dimensions, and heated for 3%: minutes at 160C to cure the ample II. The crease angles and tear strengths were measured and the results are recorded in Table XV.-  
  Emulsions H and J to L were applied to 10g pieces of scoured cellulose diacetate by the following procedure. Samples of each of the emulsions were first diluted times with water and treatment liquors were then prepared by taking 100 g/l of each of the diluted emulsions and adjusting the pH to 4.0 with acetic acid. The fabrics were treated at a liquor ratio of 20:1 for 30 minutes at 60C. In some cases hydrogen peroxide sufficient to provide a concentration of 1 volume was Table XVI Handle (21) No H addition Emulsion (b) H O; addition ra -m unoroww Untreated EXAMPLE l8 Emulsion H was applied to scoured cellulose diacetate under a variety of conditions. The emulsion was first diluted 100 times with water and treatment liquors 26-29 were prepared according to Table XVII. Pieces (10g) of cellulose diacetate were treated for 30 minutes at 60C. When a curing catalyst (hydrogen peroxide or N,N&#39;-diethylthiourea) was used, it was added after minutes. The patterns were spun, dried, and conditioned, and handle assessments were carried out as described in Example 17. Apart from Liquor 26, all the liquors were completely exhausted at the end of the treatment. The results are given in Table XVII.  
 Table XVII Treatment Liquor 26 27 28 2 Diluted emulsion H (g) 20 20 20 Aqueous Acetic acid. 571 (ml) 2 2 2 Aqueous hydrogen peroxide 20 vol. strength (ml) l0 N.N&#39;-diethylthiourea (g) 0.25 Handle 2-3 2 2 2 EXAMPLE 19 In this Example cotton poplin is cross-linked under wet conditions to improve the wet-crease recovery. Cotton poplin as used in Example 16 was padded to 70 percent retention with an aqueous liquor containing 300g per litre Aminoplast C and 100 ml per litre concentrated hydrochloric acid (36% w/w). The patterns were rolled up smoothly over a glass roller (5 cm diameter) and tightly wrapped in polyethylene sheet to prevent escape of moisture. The roller was held horizontally and slowly rotated for 18 hours to ensure homogeneous treatment. The cloth was well rinsed with water, then with an aqueous solution containing 5g/1 sodium carbonate, then with water, and dried. Some of the patterns were then padded to 70 percent retention with an aqueous solution containing either 22 30g/l of Emulsion A, or 30g/l of Emulsion A plus l5g/l of monoethanolamine. They were dried for 10 minutes at C and the tear strength and wet and dry crease recovery properties were determined on conditioned samplesf TABLE XVIII Wet crease Dry crease Tear Treatment recovery recovery strength (g) Aminoplast C only 92 47 404 Aminoplast C I06 59 436 Emulsion A Aminoplast C Emulsion A l 17 55 440 Monoethanolamine Untreated 50 50 856 We claim:  
  1. A process for modifying hydroxy-containing cellulosic fibres which comprises 1. treating the fibres, free from keratinous material, A. with a polythiol having up to six thiol groups per molecule and a molecular weight between about 400 and about 10,000, wherein the polythiol has the formula p is a positive integer of at least 2 and at most 6, q is zero or a positive integer of four or less, selected so that (p+q) equals at least 2 and at most 6,  
 each alkylene group contains a chain of at least 2 and at most 6 carbon atoms between consecutive oxygen atoms,  
 R is an aliphatic radical containing at least 2 carbon atoms, and  
 X is an aliphatic radical containing at least one thiol group, and B. with an aminoplast which is free from ethylenic unsaturation, and  
 2. curing the polythiol and the aminoplast on the fibres.  
 2. The process of claim 1, wherein q is zero or 1, p is 2 to 6, provided that when q is l, p is 2, R is an aliphatic hydrocarbon radical having at least 3 and at most 6 carbon atoms, and X is an aliphatic radical of the formula C,,H ,,SH, wherein u is l or 2.  
  3. The process of claim 1, wherein the polythiol is selected from the group consisting of those of the formulae:  
 ( CH2 (OC H O. co. C H SI-I CH2 (OC H O. co. C H S H 1 c o. H cit o v v s of (o H O e o n L C H O CO C H H CH (oc a v o. co. C H oH (c CH H ch (OC H O.CO. c a sa I (III) (IV) CIH (OC H O-CO.C H SH C H (OC H O.CO.C I-I SH I z 1 a C&#39;H (OC H OH CIH i (OC H OH i l i 5 CH (OC H O. co. c a sa (CH f i i CH C H O. co. c a sa I c H L. 2 .l. (V) and (VI) CH 0C H 0.0 S I 2 t 0 c a H CH CH (OC H O co c a sn CH c 0c 0. H H CO C H SH L2 8. c 2 (OC H O. co. C H SH in which a is zeroito, 2,  
 m is an integer of at least 1,  
 t is an integer of at least 2 and at most 3, and  
 u is a positive integer of at most 2.  
  4. The process of claim 3, wherein the polythiol is selected from the group consisting of those of the formulae:  
 I, wherein t is 3 and u is l;  
 lll, wherein t is 3 and u is l;  
 V, wherein a is 2, t is 4, and u is l; and  
  VI, wherein t is 3 and u is l, in which in is an integer of at least 1, said polythiol having an average molecular weight of at least 1000 and at most 7500.  
  5. The process of claim 1, wherein n is zero and, X is an aliphatic radical of the formula ca CHCH SH, 2 2  
 wherein,  
 R is a substituent selected from the group consisting of OH, (O-alkylene),-OH, -O.CO.C,,H ,,SH, and (O-alkylene), O.CO,C,,H ,,SH,  
 u is l or 2, and  
  v is a positive integer of at least 1. 6. The process of claim 5, wherein R is Ol-l or (O-alkylene),.OH, q is zero, p is 3 to 6, and the alkylene groups are C l-l or C l-l 7. The process of claim 6, wherein R is OH, the alkylene groups are C l-l q is zero, p is 3, R is R is -CH -C 3HCH and the average molecular weight is between about 700 and about 7500.  
  8. The process of claim 1,&#39;wherein there is used a weight of polythiol which is 0.1 to 3 percent of the weight of cellulosic fibres treated.  
 9; The process of claim 1,:in which a catalyst for curing the polythiol is also applied, said catalyst being selected from the group consisting of bases, siccatives, sulphur, sulphur-containing organic compounds in which the sulphur atoms are not exclusively present as mercaptan groups, free-radical catalysts, salts of heavy metals with acids having an acid strength (log pK) l2. Hydroxyl-containing cellulosic fibrous materials.  
 free from keratinous material, bearing thereon a cured coating from 0.5 to 15 percent by weight of a polythiol resin and an aminoplast free from ethylenic unsaturation, said polythiol resin having up to six thiol groups per molecule and a molecular weight between about 400 and about 10.000, the polythiol having the formula:  
 l (-o-a1k 1ene) OH l l l l q l R l a l T lt w l m l p l l l l 1 in which m is a positive integer of at least 1, n is zero or 1,  
  p is a positive integer of at least 2 and at most 6, p q is zero or a positive integer of four or less, selected so that (p+q) equals at least 2 and at most 6,  
 each alkylene group contains a chain of at least 2 and at most 6 carbon atoms between consecutive oxygen atoms,  
 R is an aliphatic radical containing at least 2 carbon atoms, and  
 X is an aliphatic radical containing at least one thiol group.  
  13. The cellulosic fibrous material of claim 12, wherein the polythiol is the polythiol defined in claim 2.  
  14. The cellulosic fibrous material of claim 12, wherein the polythiol is the polythiol defined in claim 3.  
  15. The cellulosic fibrous material of claim 12, wherein the polythiol is the polythiol defined in claim 4 16. The cellulosic fibrous material of claim 12, wherein the polythiol is the polythiol defined in claim 5.  
  17. The cellulosic fibrous material of claim 12, wherein the polythiol is the polythiol defined in claim 6.  
  18. The cellulosic fibrous material of claim 12, wherein the polythiol is the polythiol defined in claim 7.  
  19. The cellulosic fibrous material of claim 12, bearing thereon (A) the polythiol and (B) an aminoplast providing from 2 to equivalents of a group selected from the class consisting of N-methylol, N- alkoxymethyl, and N-acetoxymethyl groups per thiol group equivalent of said polythiol.