CA1065559A - Treatment of paper and textile fabrics with emulsified epoxy-silicones - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Paper and textile fabric substrates have been rendered water repellent by treatment of water-dispersible emulsions of epoxy-silicones where the emulsifying agent is an anionic sulfonate emulsifier.

Description

~Q~5SS~ 9592 BACKGROU~D OF THE INVENTION
This invention pertains to a me-thocl of rendering paper and textile fabric substrates water repellent by contacting them with water-dispersible emulsions of epoxy-silicones and in particular to the use of anionic sulfonate emulsifiers.
Aqueous emulsions of epoxy-silicones have been used for sizing paper and textile fabrics using non-ionic emulsifiers to prepare the water-dispersible emulslons. These previously known techniques however invariably require the use of a catalyst to obtain reasonable cure times. In the case of commercial paper board,where the presence of catalysts are un-desirable, cure times of seven to ten days are required before acceptable water repellency is imparted to the paper board. Commercial grades of filter paper treated by using non-ionic emulsions of epoxy-silicones require elevated temperatures to effect cure.
Catalysts,such as,metal salts and polymer anhydrides will accelerate the rate of cure of the substrates but their use adds to water pollution problems, production costs and also results in a short bath life for the water-dispersible emulsions of epoxy-silicones.
It is therefore an ob~Ject of this invention to provide a method for imparting water repellency to paper and textile fabric substrates with water dispersible emulsions of epoxy-silicones with shorter cure times without the addition of curing catalysts.

-2-~06SSS~ ~)5~

STATEMEN~ OF THE INVENTION
A method of imparting water repellency to paper and textile fabric substrates has been developed which comprises contacting the substrates with a water-dispersible emulsion of an epoxy-silicone having the formula:
I MD U M' x y q wherein D represents an R2SiO unit in which R is a monovalent hydrocarbon radical free of acetylenic un-saturation; U represents a unit selected from the classconsisting of R' R-Si-O and R'-Si-o3/2 in which R is defined above and R' is a monovalent organic radical containing at least one vicinal epoxy group, M and M' are in each occurrence an end blocking unit having the formula:
~ R' . a

3-a i 1/2 in which R" is a monovalent hydrocarbon radical free of olefinic unsaturation, R' is as defined above, a has a value from 0 to 1 inclusive, q has a value of 1 when U is an R' R-Si-O
unit and a value of (y -~ 1) when U is an R'SiO3/2 ~655S~
unit, x is an integer having a value oE Erom 10 to about 105, y is an integer having a value of 1 to 102, the s~ of x, y~ and q being such tha-t the epoxy-silicone compound MDXUyMlq has a molecular weight of from 10 to about 106 and the ratio of epoxy-containing unit to uni~s containing no epoxy g~oups is withln the range of from about 0.001 to 0.5, said epoxy-silicone being employed in an amount of from a'bout 0.01 to about 4 weight percent based on~the weight of dry substrate, the improvement which comprises using about 1 to 25 weight percent of an anionic sulfonate emulsifier based on the,weight of the epoxy-silicone.
It is to be understood that the overall average molecular weight of the epoxy-silicone used is not narrowly critical. Whereas silicones having molecular weights of several thousand, viz., one thousand to fifty thousand perform advantageously the only signif-icant limitation on the maximum molecular weight values is the high viscosity of very high molecular ; 20 weight polymeric epoxy-silicones. Although very viscous epoxy-silicones are still suitably employed they are inconvenient to utilize and thus are not preferred.
Illustrative of the monovalent hydrocar~on radicals represented by R in the R2SiO1/2 and 959~
1136SSS1l3 R' R-SiO1~ 2 units de~ined above for U are alkyl groups containing rom 1 to 10 carbon atoms, preferably 1 to 6 carbo~
atoms such as methyl, ethyl, propyl~ butyl, isobutyl, amyl, hexyl, octyl, and decyl; alkenyl groups such as vinyl, allyl, butadienyl, l-pentenyl and the like;
aryl radicals including fused ring structures such as phenyl, p-phenylphenyl, naphthyl, anthryl and the like;
alkaryl radicals such as tolyl, ~ylyl~ p-viny1phenyl, ~-methylnaphthyl, and the like; aralkyl radicals such as stearyl, phenylmethyl and phenylcyclohexyl; and cycloalkyl radicals such as cyclopentyl, cyclohexyl and;cyclobutyl -Preferred R radicals are alkyl with methyl being particularly preferred.
The monovalent organic radicals represented by R' which contain epoxy groups are, exclusive of the ~oxirane~oxygen necessarily present, preferabLy hydro-carbon radicals~free of acetylenic unsaturation or ~containing in addition to carbon and h~drogen only ether or carbonyl oxygen. Such R' radicals include 3,4-epoxycyclohexyl; 6-methyl-3,4-epoxycyclohexyl;
3-oxatricyclo~3.2.1.02 9 4]octane-6-propyl; 7-butyl-3-oxatricyclo~3.2.1.02~4]octane-6 methyl; 334-epoxycyclohexyl-l-ethyl; 9,10-epoxystearyl;

- ' ' ~-glycidoxypropyl; p-(2~3-epoxybutyl)phenyl; and 3-(2,3-epo~ybutyl)-cyclohexyl. The vicinal epoxy group can be but need not be a terminal group of the ~' radical. Moreover, the R' radical can be simply a H

.` - C -~ CH2 radlcal directly joined to silicon. A variety of epoxy-silicones which are hereinbefore defined are illustrated~structurally and further characterized with respect to physical properties in J.A.C.S.-, vol. 81, at pages 2632 - 2635, E. P. Plueddemann et al.
Because of ready availability of precursors and the excellent results obtained using the final product the preferred units of Formula I above are M = M = (~H3)35iOlj2 and D = (CH3)2SiO. More per-ticularly preferred are the silic~ containing these M and D units in combination with at least one U unit of the formula:

o ~ H3)Si-C2H4 or (CH3)Si-C3H60CH2-C/0 CH2 which pol~mers have the structure .

106S~5~ 9592 MD UyM

wherein y is an integer having a value of from about S to about 15 and x îs an integer having a value of rom about 200 to about 600.
The aforesaid silicones are well known in the art and can conveniently be prepared, among other methods, by the platinum catalyzed addition o-E ali-phatically unsaturated epoxy compounds to hydro-siloxanes, the ratio of reactants being such as to prevent the presence of unreacted, i.e., residual, hydrosiloxane moieties. It is to be understood however that trace hydrosiloxane contamination in the silicone can be tolerated without unduly affectin~ the compositions and processes of this invention, but preferably the silicone is hydrosiloxane-free. By ¦ trace amounts of hydrogen-siloxane is meant not more than that amount which will produce about 2 cc.
hydrogen per gram of silicon by the NaOH gas evolution I method.
¦ 20 Although the prior art has disclosed that the above group of epoxy-silicones may be emulsified with ; either non-ionic, cationic or anionic emulsifiers, there was no recognition of the unexpected property that anionic sulonate emulsifiers act as catalysts to effect rapid curing of these epo~y-silicones.

~ ~ 6 Ss S ~ 9592 Not all anionic emulsifiers possess the unusual properties exhibited by the anionic s~llfon,ate emulsi-fi~rs. Thus Eor example sulfuric acid esters or alcohol sulfates such as lauryl sulfate, s~dium 2-ethyl hexyl sulfate, alkylaryl polyether sulfates and the like, carboxylic acid salts such as morpholine oleate, and aromatic phosphate esters do not exhibit as rapid a curing effcct as that shown by the sul-fonates of this invention.
Preferred sulfonates include alkali metal dialkyl sulfosuccinates containing 14 to 2~
carbons, alkali metal, morpholine and alkanolamine salts of alkylaryl sulfonic acids, alkali metal salts of alkylaryl polyether sulfonates, alkali metal salts of alkyl naphthalene sulfonates, and alkane sulfonates 4 Particularly preferred anionic emNlsifiers are the ~riethanolamine salt o~ an alkylaryl sulfonlc acid commercially available as Richonate (Trademark) S-1280, ~he sodium salt of an alkyl aryl polyether sulfonate com-mercially ava~lable as Triton (Trademar~) X-202, the sodium salt of an alkyl napthalene ~ulfonate commerclally a~ai~lable as Alkanol BG and Cl7H33(CH3)-C2H4S03Na7 commercially avail-able as Igepon (Trademark) T-43.
While the catalysis of the curing of the epoxy-silicones is unique to these anionic emul~if~ers~ they may be used in conjunction with non-ionic or polymeric l~S~5~3 9592 emulsifiers, such as, polyvinyl alcohol if desired.
Another advantage of the use of anionic emulsi-fiers over non-ionic emulsi~iers in water dispersible emulsions of epoxy-silicones is that the former may be used in a neutral pH medium whereas the latter require an acid pH medium. This is often undesirable since acid pH causes weakening of paper and particu-larly textile fibers as well as causing corrosion of manufacturing equipment.
While about 1 to about 25 percent of anionic emulsifier based on the weight of epoxy-silicone can be used in this invention, it is preferred to use about 1 to about 10 weight percent and even more preferred to use about 3 to about 5 weight percent.
While about 0.01 to about 4 weight percent of the epoxy-silicone based on the weight of the sub-strate can be used to gain the advantages of this invention, it is preferred to use about 0,025 to about 0.5 weight percent.
The emulsions of this invention may be applied to paper and textlle fabric substrates by any of the various techniques known in the art for surface application. On paper these include application by means of a water box on a calendar, tub siæing, sîze press, transfer roll, spraying and the like. The _9_ lQ6SSS9 9592 ,.
emulsions can be applied either before, during or after the paper forming operation.
The addition o the active agent, i.e., the epoxy-silicone to the paper fibers prior to the tim~
when they are interfelted into a relatively low water content, self-supporting sheet is conventionally termed "wet end sizing'l. Similarly, when the epoxy-silicone is applied to the already formed paper the process is referred to as 'ldry end sizing'l.
If des~ired retention aids well known in the art can be used for the application of the epoxy-silicones to the pulp fibers. These include gums, starches~ and resins such as polyethyleneimine, sulfonium metal sulfate salt of an acrylic acid-acrylamide copolymer~ cationic starches, cationic silicones, polyamine epichlorohydrin and carboxy-methyl cellulose.
While statements have been made that epoxy-silicones emulsified with aqueous soLutions o non-ionic emulsifiers can be used without beneit ofcatalysts or elevated temperatures, the length of time needed for curing is so great that it is not practical in many cases to employ this technique, This invention now reveals a method for gaining ~ast curing times without the beneit of catalysts or elevated temperatures. This is not to say that -10~

~0~5S5~ 9592 catalysts can't also be used if still fa~ster curing times ar~ desired. A suitabLe catalyst often used by paper makers ls aluminum sul~ate. This can be al~erna-tively added in a separate application at the dry end ; or added directly to the diluted emulsion of epoxy-silicone. Other cataLysts which may be used if desired include the metal salts of strong acids such as zinc nitrate and polymeric anhydrides, such as, poly (methyl vinyl ether/maleic anhydride), poly (styrene/maleic anhydride), and tetrapropenylsuccinic anhydride.
On textiles, a typical method of application is that known in the art as dip-pad-dry. The emulsion may be applied after all other finishing operations have been completed or may be applied along with other finishing agents. As in the case of paper treating no catalyst is needed to obtain fast cures but if desired the catalysts enumerated above and also metal soaps such as zinc 2-ethyl hexoate or dibutyl tin diacetate ¦ 20 or laurate may be used in te~tile fabric finishing operations using the emulsion for this invention. The ~ metal salts enumerated above are generally used in a ¦ ratio of 0.1-10 parts by weight to 100 parts of epo~y-s;licone and more commonly about 2 parts of the former to one hundred parts of the latter.
For textile finishing the epoxy-silicone ;S5S~
emulsion o-E this invention can be applied in conjunc-tion with modiying resins and other texti'Le finishing materials. These other finishing materials include starch, other water repellents, either organic or silicone type, oil repellents, wash-wear resins, - organic softeners and lubricants~ dyes and pigments, anti-slip agents and the like. The epoxy modified silicones have been appLied in conjunction with wash-wear resins(dimethylolethylene urea or triazone), and excellent water repellency, softness and tear strength was obtained.
~ le invention is further described in ~he examples which follow. All parts and percentages are by weight unLess otherwise specified.

An epoxysilicone sizing agent was prepared by mixing together 8.75 grams of a 2 centistoke trimethyl end-blocked dimethylpolysiloxane, 18.0 grams of a trimethyl en'dblocked methylhydrogenpolysiloxane, 974.8 grams dimethylpolysiloxane cyclics (depolymeri-zate) and 20 grams conce~trated sulfuric acid. After agitating this mixture for 2 1/2 hours, the viscosity increased to form a viscous fluid. To this was added 200 cc of toluene and 50 grams of sodium bicarbonate, The composition was stirred for 1 hour and then heated to 180G. and sparged with nitrogen at 2 liters/minute ~ 0~ S S S 9 9592 for 2 hours. When cool the material was filtered.
The resulting oil had a viscosity of 3000 centi-poises, a hydroxyl content Less than 0.1 weight-percent, and a silanic hydrogen content of 6.3cc.
H2/gram using the caustic hydrogen evolution test.
400 Grams of this fluid were mixed with 100 grams isopropylether, 14.4 grc~ms vinyl-3, 4-epoxycyclo-hexene, and 10 parts per million platinum in the form of chLoroplatinic acid. The resulting mixture was heated to 85C. and the rapid refluxing indicated an exothermic reaction had occurred. After heating 2 hours at 85C , 1 gram benzothiazole was added, and mixed for 10 minutes. The polymer was cooled and filtered using a filter aid. The polymer was returned to a kettLe and sparged with 2 liters ` ~:
N2/minute at 135 C. When solvent no longer was being removed, the material was vacuum sparged at ~ 40 mm. pressure for 1 hour. The product had the following analysis; epoxy content, 1.0 ~3%, silanic hydrogen, 1.2cc, H2/g.
This product corresponds to the formula:
(CH3)3SiO 1(CH3)2SiO]~90 ~CH3Si]10Si~CH3)3 C2H4 _~0 ` An emulsion of the epoxy-silicone prepared above was prepared using 3% of an anionic surfactant ~; based on the w~ight of epoxy silicone. The anionic ; ~ -13~

~ 9592 l~S5S9 TABLE I
Room Cure Temp, Test Emulsifier Spray Rating-Cotton Time Stabil-_ Catalyzed Unc ~ Iyzed Paper ity A Morpholine salt of 100 90 O 6 dodecyl benzene months sulfonic acid (anionic) B Triethanolamine 90 9~ 2 6 saLt of dodecyl m~ months benze~e sulfonic acid (anionic) C Sodium sal~ of 100 80 c 5 5 dodecyl benzene m~b~ months sulfonic acid (anionic) D Sodium salt of 100 70 ~ 5 Creams alkylaryl poly- m~u~es ether sulfonate( (anionic) _ _ . ~
- Control Sodium 2-ethyl 90 80 5 Creams A hexyl sulfate nnnut~
(anionic) ~Control Sodium Sal~ of 90 70 5 Separ-: ~B alkyIaryl pol~ ) minutes ates ether sulfate : ~anionic) Control Sodium ~a~ryl __ __ 10 Crea~s C sulfate~CJ plus min.
polyvinyl alcohol : (anionic) Control Organic ester of ~0 __ ~15 4 D phosphoric aCid(d) . ninutes Months mor~holine s~t (anlonic ) :Control Nonylphenoll 70-80 50-70 15 6 ethylene oxide . mnut~s Months adduct (1:20) ~us trimethylnonanol (non~ionic) (a)Triton X-202 (Trademark of Rohm and Haas Co.~
)Triton X-301 {Trademark o~ Rohm and Haas Co.) (C3Dupanol WAQ (Trademark of duPont Co.
(d)GAFAC RE-610 (Trade~ark of ~AF Corp.) 13(a) ,,.~

~ 6sss9 9592 surfactant was the morpholine salt o dodecyl-benzene sulfonic acid (Richonic Acid B sold by Richardson Company). The room temperature stability of this emulsion was six months.
The water emulsion prepared above was tested for its ability to impart water repellency to samples of 80 X 80 cotton print cloth using the Spray Rating test for water repellency, Test Method 22-1971 o~ the American Assoc. of Textlle Chemists & Colorists (AATCC) at a 1.2 percent loading of epoxy-silicone using G.03 percent of zirconium acetate as a catalyst in one se~
of tests and no catalyst in another set of tests. The ~` cure time on Whatman ~Trademark) NoO 3 filter paper treated with 0.05 percent aluminum sulfate was measured by recording the tlme ~or the Cobb value to reach a minimum.
The Cobb test is a measure of water repellency which consists of exposing a specific surface area of the paper to water for a given time and measuring the amount of water absorbed by the gain in weight. This test is described in TAPPI (Tech~ical Association of the Pulp and Paper Industry) Standard T-441. Unless otherwise noted in this and other succeeding examples, the Cobb tes~ was made using water at 49C. exposed to the paper for 3 minutes. The room temperature stabiLity of the emulsion so prepared was also observed. The results ob~ained are delinea~ed in -14~
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lo~SSS~ gss2 Table I together with a comparison of other emulsions prepared with both the anionic emulsifiers of this invention and the nonionic emulsifiers of the prior art. As can be seen from an examination of these data onLy the narrow class of anionic emulsifiers specified above functions to afford short cure t~nes on paper coupled with hig~l spray ratings on the cotton print cloth. In most cases the added benefit of good room temperature stability was also obtained. In contrast the nonionic emulsion of the same epoxy-silicone is markedly inferior as are other anionic emulsifiers which are outside the ambit of this invention.

Example 1 was repeated with varying portions of reactants to give several examples of epoxy-silicone where the x andy values of the general formula MDX-UyM'q were varied to demonstrate the broad applicability of the preferred em~lsion disclosed herein. These were made to varying epoxy contents and also evaluated as emulsions for ~reatments of cotton printcloth, Dacron (Trademark) cotton, and Whatman ~Trademark) No. 3 ~ilter paper. The results obtained are presented in TabIe II. These dat~
demons~ra~e tha~ the anionic emulsions prepared from the trie~hanolamine salt of dodecyl benzene sulfonic ac~d give much faster cure times on filter paper as compared with the nonionic ~mulsion. The spray rating of these ~ -15-, 9592 TABLE III

Water Absorption by Cobb Test TAPPI Test Method T-441 Paper treated with Anionic Emulsion Cobb Paper No Silicone of Test 1 Substrate Control F Fpoxy-Silicone Time( ) _ _ .
newsprint 110 g~/m2 25 g/m 180 seconds unbleached 40 g./m 2 g/m2 180 Kraft . seconds . 2 reclaimed . 150g/m 110 g/m 2 hours : Kra~t and : . newsprint : .
(1) Water at 27C. exposed to paper for designated time.

~, :

~ ' ' ' ~: .

~ 15(a) ~:

` ~655~9 9592 .
anionic emulsions wa~ al~o observed to be excellent.

The sizing of various paper substrates was evaluated using the epoxy-silicone prepared as ;n Example 1 emulsified with the morphol;ne salt of dodecyl benzene sulfonic acid. Newsprint, unbleached Krat and reclaimed Kraft and newsprint were used in this evaluation. The results compared with Control F
having no epoxy-silicone on the paper substrate are presented in Table III. The significant amount of water repellency imparted to all three types of paper is amply demonstrated by these data.
EXoMPLE 4 A comparison of the water repellency imparted to 80 X 80 cotton print cloth and 65/35 Dacron (Trade-mark)/cotton poplln by a nonionic epoxy-silicone water emNlsion of the prior art and an anionic emulsion of the same epoxy-sllicone was made. Spray ratings were taken with the treated cotton print cloth and cotton poplin initially after trea~ment and then after one wash and five washes performed in conformity with the American Association of Textile Chemists and Colorists (AATCC~
test method 124-1967 with a machine wash at about 60-63~C, The treatment of the print cloth and popli~
was effected by dipping the fab~ic in the dilute emulsion, padding off the exces~ and drying the ~reated ~ -16-.'''r5 ~6 S5 S ~ 9592 TABLE IV

(2) Spray Ratings Emulsifier Load % 80x80 Cotton P~nt o~ 65/35 DQcron/Cotton Initial lWbsh 5 Washes ~ t~c pll~nh 5W~hes . _ . ~ . _ .

Non-ionic 1.6 80 70 70 70 70 70 1.2 70 70 70 70 70 70 0.8 70 70- 50 70 70 70 0.4 70 70- 50 80- 70 70-, _ = -_ . _ . _ _ . _ Anionic 1.6 100 80 70100 90- ~0 1.2 90 80 70100 80~ 80 : 0.8 90 80 7090+ 801 80 0.4 ~0 70 70-90+ 8 80-( ) AATCC Test Method 22-1971 Condition: At least 24 hours before Spray Rating Wash: AATCC 124-1967, Machine Wash at 60-63C.

~ (2) Based on weight of fabric.

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o ~ o ~ n 16 (b ) ~ 0 ~ S~ S 9 9592 fabric in a forced air oven at 160C. for 5 minutes, miS standard procedure is referred to by those skilled in the art as dip-pad-dry. The results presented in Table IV are those obtained with a non-ionic emulsion of the epoxy-siticone prepared in Example 1 emulsified with nonylphenol/ethylene oxide adduct (1:20) pLus trimethylnonanol. The anionic emulsion employed the morpholine salt of dodecyl-benzene sulfonic acid with the epoxy-silicone prepared in Example 1. The data in Table IV clearly show the superiority of ~he anionic emulsion over the non-ionic emulsion.
EXAMPLE S
The superiority of the anionic emulsion vf the epoxy-silicone prepared in E~ample 1 over that of the non-ionic emulsion of the same epoxy-silicone using the same emulsifiers as in Ex~mple 4 was demonstrated by applying the curing emulsions to Whatman (Trademark) No. 3 filter paper treated with decreasing amounts of aluminum sulfate and curing at 90C. ~or 15 minutes and 60 minutes respectively. The data obtained pre-sen ed in Table V again de~onstra~e the su~eriority of the anionic emulsified epoxy-silicone over that of the nonionic emulsified epoxy-silicone as to imparting water repellency to paper, This water absorption test was carried out using ~he Cobb Test~

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17 ~a) ~ ;55S~ 9592 The superiority of the anionic emulsifiers outlined above over non-ionic emulsifiers for the room te~perature trea~ment of Whatman (Trademark) No. 3 filter paper was demonstrated us~ng the epoxy-silicone Pre-pared in Example 1 emulsifled with each of seven emulsifiers. The data presented in Table VI ~how tha~ all of the anionic emuLsifiers are significantly superior in reducing the water absorption of the paper treated with the emulsified epoxy-silicone after drying for two hours at room temperature.

A further demonstration of the su~eriority of the anionic emulsions of this invention ovPr the prior art non-ionic emulsions was demonstrated by the improved water resistance imparted by an aqueous emulsion prepared by emulsifying the epoxy-silicone of Example 1 with nonylphenol/ethylene oxide adduct (1:20 plus trLmethyLnonanol (non-ionic) and one prepared by emulsifying the same epoxy-silicone with the morpholine salt of dodecyLbenzene sulfonic acid ~anionic). This improved water resistance was demonstrated by a water drop penetration test with ~hatman (Trademark) Na. 3 fil-ter paper which was previously t~eated in one case with the non-ionic emulsion and in another wlth the anionic e~ulsion ~ -18-~SSS~
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by dipping the filter papers into the dilut~e emulsions and drying at room temperature for about 18 hours. A
Control of filter paper was also used untreated with either emulsion. The time required for a water drop to be completely absorbed by a sample of Whatman (Traden~rk~
~o. 3 filter paper took two seconds in the case of the unt~eated s~mple, 17 seconds in the case of the non-ionic emuls~on treated paper and 71 seconds ln the case of the anionic e~ulsion treated paper.
EXA~qE 8 The effectiveness of the anionic emulsified epoxy-silicone over that of the non-ionic epoxy-silicone at lower loadings was also demonstrated using the Cobb test for ~Jater absorption (TAPPI Method T-441).
Whatman (Trademark) No. 3 filter paper was treated with the non-ionic and anionic emNlsified epoxy-silicone solu-tions respectively and cured for 30 minutes at 90C. The differences between the two emulsions is demonstrated by the data presented in Table VII.
Although the in~ention has been described in its preferred forms with a certain degree of particularlty, it is understood that the present disclosure of ~he preferred forms has been made only by way of example and that numerous changes may be resorted to wi~hout departing rom the spirit and scope of the in~ention.

.~;3 '~

Claims (17)

WHAT IS CLAIMED IS:

1. In the method of imparting water repellency to paper and textile fabric substrates which comprises contacting the substrates with a water-dispersible emulsion of an epoxy-silicone having the formula:
M DXUyM'q wherein D represents an R2SiO unit in which R is a monovalent hydrocarbon radical free of acetylenic unsaturation; U represents a unit selected from the class consisting of in which R is as defined above and R' a monovalent organic radical containing at least one vicinal epoxy group, ; M and M' are in each occurrence an endblocking unit having the formula:

in which R" is a monovalent hydrocarbon radical free of olefinic unsaturation, R' is as defined above, a has a value from O to 1 inclusive, q has a value of 1 when U
is an unit and a value of (y + 1) when U is an R'SiO3/2 unit, x is an integer having a value of from 10 to about 105, y is an integer having a value of from 1 to about 102, the sum of x, y and q being such that the epoxy-silicone compound MDxUyM' has a molecular weight of from about 103 to about 106 and the ratio of epoxy-containing units to units containing no epoxy groups is within the range of from about 0,001 to 0.5, said epoxy-silicone being employed in an amount of from about 0.01 to about 4 weight % based on the weight of dry substrate, the improvement which comprises using about 1 to 25 weight % of an anionic sulfonate emulsifier based on the weight of the epoxy-silicone.

2. Method claimed in claim 1 wherein the emulsifier is a salt of an alkylaryl sulfonic acid.

3. Method claimed in claim 2 wherein the salt is an alkali metal salt.

4. Method claimed in claim 2 wherein the salt is a morpholine salt.

5. Method claimed in claim 2 wherein the salt is an alkanolamine salt.

6. Method claimed in claim 1 wherein the emulsifier is an alkali metal dialkyl sulfosuccinate.

7. Method claimed in claim 1 wherein the emulsifier is an alkylaryl polyether sulfonate alkali metal salt.

8. Method claimed in claim 1 wherein the emulsifier is an alkyl naphthalene sulfonate alkali metal salt.

9. Method claimed in claim 1 wherein the emulsifier is an alkane sulfonate.

10. Composition suitable for imparting water repellency to paper and textile fabric substrate com-prising a water-dispersible emulsion of an epoxy-silicone having the formula:

MDxUyM'q wherein D represents an R2SiO unit in which R is a monovalent hydrocarbon radical free of acetylenic unsaturation; U represents a unit selected from the class consisting of and in which R is as defined above and R' is a monovalent organic radical containing at least one vicinal epoxy group, ; M and M' are in each occurrence an end blocking unit having the formula:

in which R" is a monovalent hydrocarbon radical free of olefinic unsaturation, R' is as defined above, a has a value from 0 to 1 inclusive, q has a value of 1 when U
is an unit and a value of (y + 1) when U is an R'SiO3/2 unit, x is an integer having a value of from 10 to about 105, y is an integer having a value of from 1 to about 10 9 the sum of x, y, and q being such that the epoxy-silicone compound MDxUyM'q has a molecular weight of from about 103 to about 106 and the ratio of epoxy-containing units to units containing no epoxy groups is within the range of from about 0.001 to 0.5, said epoxy-silicone being employed in an amount of from about 0.01 to about 4 weight % based on the weight of dry substrate, and about 1 to about 25 weight % of an anionic sulfonate emulsifier based on the weight of the epoxy-silicone.

11. Composition claimed in claim 10 wherein the emulsifier is a salt of an alkylaryl sulfonic acid.

12. Composition claimed in claim 11 wherein the salt is an alkali metal salt.

13. Composition claimed in claim 11 wherein the salt is an alkanolamine salt.

14. Composition claimed in claim 10 wherein the emulsifier is an alkali metal dialkyl sulfosuccinate.

15. Composition claimed in claim 10 wherein the emulsifier is an alkylaryl polyether sulfonate alkali metal salt.

16. Composition claimed in claim 10 wherein the emulsifier is an alkyl naphthalene sulfonate alkali metal salt.

17. Composition claimed in claim 10 wherein the emulsifier is an alkane sulfonate.