US2402351A - Water repellent composition and the process of preparing the same - Google Patents

Description

Patented June 18, 1946 WATER REPELLENT COMPOSITION AND THE PROCESS OF PREPARING THE SAME Joseph Edward Smith and Paul Jones Mitchell,

Jr., Wilmington, DeL, assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a

corporation of Delaware No Drawing. Application February 21, 1945, Serial No. 579,160

Claims. (Cl. 106-134) 1 This invention relates to compositions of matter for use in the finishing of textile materials. More particularly this invention relates to aqueous dispersions of waxes of the type used for im- Parting a Water repellent finish to textile fabrics.

aluminum salts, such as acetate or formate, have a degrading action on glue or gelatin, and if the.

manufacture is eflected by a process involving prolonged milling of the reagents at elevated temperature (near the boiling point of water) the aluminum salt in some manner destroys the powers of the protective colloid to stabilize the dispersion. In storage, the aluminum salt exerts It is an object of this invention to provide a 5 a similar influence on the colloid, though at a process for producing water-repellency composlower rate. Consequently, diificulties have been sitions of the above character in the form of conexperienced in the storage and use of water-repel- 'centrated aqueous dispersions, characterized by lency compositions of the above nature, due to i h stability on storage in wooden or glass conseparation of the dispersion into two or more laytainers. A further object is to produce compoers in the container, frequently with the formasitions of the above character having high eifection of a. heavy non-dispersible wax crust at the tiveness when applied as a water-repellency fintop. This tendency to separate is pronounced ish to textile fibers, and having a high degree of when the compositions are packed in wooden constability when diluted into an aqueous bath in the m tainers and is particularly noxious when the comprocess of applying to the fiber. Other and furpositions are packed in glass containers. ther important objects of this invention will ap- When the composition is diluted with water topear as the description proceeds. form the textile treating bath, additional dim- It is old in the art to render textile fiber waterculties are often encountered, characterized by repellent by treating the same with an aqueous 2 partial coagulation of the diluted dispersions, dispersion or emulsion of a paraffin wax or oil. with the formation'of particles which deposit It has also been known that for proper eifectivewaxy spots on the goods. ness the composition must also contain a water- The use of surface active agents such as soap, soluble salt of aluminum or other multivalent sulfonated oils and aromatic sulfonic acids as metal. It is also well known that to prevent the additives to glue to improve the emulsifying acdispersion or emulsion from settling out quickly, tion of the glue for waxes and oils has been the same must contain further a protective colbroadly taught in the prior art (U. S. 2,015,865). loid, such as glue or gelatin. Accordingly, the However, while these additives do help in obtainpatent literature is replete with reference to lug emulsification by glue in the absence of waterwat'er-repellency composigns in the form of aque- 3o soluble aluminum salts or heavy metal salts, their ous dispersions and @Ffiprising the following emulsifying power is negligible after these salts three principal ingredients: are added since their aluminum salts and heavy (1) Water-insoluble waterproofing substances metal salts are usually water-insoluble. The such as paraffin waxes and oils, vegetable oils and aluminum and heavy metal salts of these surface fats, animal and vegetable waxes, metal soaps of 85 active agents frequently promote water in oil saturated and unsaturated fatty acids, waxy rather than oil in water dispersions or emulsions acids, resin acids or naphthene acids. and hence usually promote instability rather (2) A salt of a multivalent metal such as aluthan stability of oil-in-water type dispersions and minum, magnesium, zinc, lead, copper, zirconemulsions. a ium, thorium, uranium, titanium and iron. 40 Now according to this invention, We have found (3) A water-soluble protective colloid such as that small amounts of water-soluble salts of diglue, gelatin, starch, casein, vegetable proteins, naphthyl-methane-disulfonic acid, for instance gums, polyvinyl alcohol, alone or together with an the disodium salt, when used by a preferred proauxiliary emulsifying agent such as soap, sulfocedure as described below, have a stabilizing acnated oils or fats, aromatic sulfonic acids, and tion on water repellent compositions containing sulfonated mineral oils. waxes and aluminum acetate or formate dispersed See for instance U. S. P. 2,015,864 by Miiller in an aqueous glue solution, so that the composiand Stenziger; U. S. P. 2,015,865 and 2,111,402 by tions have high storage stability in wooden and Muller; and U. S. P. 2,187,858 by Kern. glass containers. The compositions have excep- Unfortunately, the stability of such composio i nally hi h stability in use and can be ap tions in storage and shipment is far from satisto textiles by impregnation of the goods in a padfactory and serious difiiculties have been encounding mangle or quetsch at temperatures of 80 F.- tered in meeting the standards of the trade re- 180 F. without the formation of spots on the garding water-repellency compositions. The root goods. The products are also highly stable when of the trouble'seems to reside in the fact that pp t t l in a Wash W el Such as is used in laundries. V

The stabilizing action is obtained by incorporating the dinaphthyl-methane-disodium-sulfo- 2,4oass1 nate in the glue solution prior to adding the aluminum salt and the waxes. The amount of dinaphthyl-methane-disodium-sulfonate used is critical and is from 0.8 to 3.2% on the weight of the glue. If the order of addition is changed so that the aluminum salt is added to the glue solution beforeadding the dinaphthyl-methane-disodium-sulfonate. no improvement over the performance of glue alone is obtained.

In the past, it has been diilicult to control the preparation of the wax-type, water-repellent dispersion, because deterioration of the glue or gelatin during the prolonged milling process frequently leads to the formation of products of poor stability. The addition of the dinaphthylmethane-disodium-sulfonate to the glue as described above markedly improves its properties so that careful control of temperature, time of milling and aluminum ion concentration during manufacture is not required. For example, it is possible to obtain an entirely satisfactory stable emulsion by simply adding the stabilizer to the glue solution, then adding all of the aluminum melting point of the wax, and even as high as 200 F, or higher, and milling for a reasonable period, say two to four hours. Such performance in operation means that process control can be simplified and uniformity of highly stable production is assured.

The invention is illustrated but not limited by the following examples. Parts mentioned are by weight.

Example 1 5.2 parts of a good grade commercial glue (Keystone Hide Glue No. 1) were dissolved with stirring in 32 parts of water at 80 C., and 0.3 part of a 30% aqueou solution of dinaphthyl-methane-disodium-sulfonate were added. After allowing the solution to stand for minutes, 18 parts of a 22% basic aluminum formate solution were added. A molten wax mixture consisting of 22.5 parts of a refined paraffin wax (Aristowax, M. P. 63 C.) and 2.5 parts of beeswax (lemon yellow grade) and heated to 95 C., was then stirred in and the aqueous mass was agitated by a high speed mixer for 30 minutes at 80-85 C., until the particle size of the emulsion was reduced to about 2 to 3 microns. Agitation was now continued at the same temperature but at a slow speed for 3 hours and then again at high speed for 15 minutes. Small portions of hot water were added from' time to time, to compensate for evaporation losses. At the end of the milling operation parts of hot water (8085 C.) were added, and the mass was allowed to cool to room temperature.

In additional experiments, the above procedure was repeated with quantities of the disulfonate varying from 0.15 to 1.2 parts of the 30% aqueous solution. In one experiment the disulfonate was omitted altogether.

It was observed that the addition of the disulfonate caused the glue solution to thicken, It also increased the rate of particle-size reduction during the subsequent wax emulsifying step.-

Water-repellency tests with the resulting emulsalt and the wax at a temperature above the sions upon cotton and rayon fabrics, in which the experiments were now stored in glass jars and observed for stability at the end of six months. The results were as follows:

Percent DMDS based Condition of dispersion Sample on weight after six months of glue l None Broken. 0. 8 Good.

1. 0 U0. 2. 4 Do. 3. 2 Fair, tendency to sediment. ii. 4 Broken.

Example 2 3.9 parts of a good grade commercial glue (Russian Glue No. 1142) were dissolved with stirring in 33 parts of water at C., and 0.4 part of a 30% aqueous solution of dinaphthyl-methanedisodium-sulfonate were added. The solution was allowed to stand for 15 minutes, and 27 parts of a 22% aqueous solution of basic aluminum formate were added. A molten mixture of waxes, consisting of 23.6 parts of refined paraflln wax (Aristowax, M. P. 63 C.) and 2.65 parts of beeswax (lemon yellow grade). and heated to C., wasnow stirred in, and the mass was put through the same time cycle of agitation as in Example 1. At the end of the milling cycle, 20 parts of water at 80 C. were added, and the mass was allowed to cool to room temperature.

In another experiment, the above procedure was repeated except that the quantity of DMDS was 0.26 part instead of 0.4 part. In a third experiment the disulfonate was omitted altogether.

The dispersions thus obtained were stored in glass Jars and observed for'stability after some time. The samples containing DMDS were found perfectly homogeneous and stable after 1 month. The third sample was found separated into two layers at the end of one week.

It will be clear that the above examples are merely illustrative and that numerous changes in the details thereof may be made in practice, without departing from the spirit of this invention.

Thus, in lieu of the wax mixtures specified, a wax consisting of a single component, namely-a hydrocarbon wax melting within the range of to 175 F., may be employed. The invention is also applicable to mixtures of the said hydrocarbon waxes with various animal and vegetable waxes of the ester type. The preferred animal and vegetable waxes for use in admixture with hydrocarbon waxes are those of the ester type having a melting range within the limits to 200 F. and a saponification value within the range of 60 to 100. Aluminum soaps and heavy metal soaps may also be incorporated in the hydrocarbon waxes as part of the dispersed phase.

As water-soluble aluminum salt, basic aluminum formate may be replaced by basic aluminum acetate, aluminum triacetate or aluminum triformate. I

The practice of this invention is not confined to the type of agitation described in the examples. Other equipment and other time-cycles of agitation may be employed. As examples of suitable emulsiflcation equipment are homogenizing valves, turbulent-flow-tube systems, centrifugal pumps or any similar system in which the concentrated emulsion isforced repeatedly through a close clearance.

The temperature for preparing the emulsion is the dinaphthyl-methane-disulfonic acid such as the potassium and ammonium salts may be used.

During the emulsiflcation step which follows next, it is preferable to have some aluminum salt present.v Even as little as 0.1 to 0.2% on the weight of the waxes to be emulsified has a perceptible efiect in increasing the emulsifying action of the glue. However, larger amounts may be added at this step, or if desired the entire amount of the aluminum salt to be used in the composition may be added at the emulsificatlon step, provided it is entered after the addition of the dinaphthyl-methane-disulfonic acid salt. The addition of the wax or waxes may precede or follow the incorporation of the aluminum salt.

As a matter of preferred practice, the aqueous dispersions prepared according to this invention will generally contain by weight:

Per cent (1) A wax comprising paraffin wax either by itself or in admixture with an ester type wax to 40 (2) An aluminum salt selected from the group consisting of normal and basic aluminum acetates and formates 4 to 6 (3) Amodified protective colloid 1.5 to 8 said modifiedprotective colloid being a complex organic compound obtained by reacting 100 parts of glue or gelatin with from 0.8 to 3.2 parts of a water-soluble salt of dinaphthyl-methane-disulfonic acid.

The mechanism by which the dinaphthylmethane-disulfonic acid salt acts as a stabilizer for the compositions of this invention is not entirely clear. It is known that the dinaphthylmethane-disulfonic acid salt acts as a precipitant for glues and gelatins and has a tanning action on hides. (See U. S. P. 1,191,480.) Aluminum salts, such as aluminum formate or aluminum acetate, are likewise known to have a precipitating and degrading action on glue and gelatin, particularly in the presence of heat; and it is this action of the aluminum salts on the glue which leads to the instability of the Water-repellent compositions of the prior art. It is very surprising therefore that addition of DMDS should stabilize the glue against the degrading action of the aluminum salt. The only plausible explanation that can be oifered is that the dinaphthyl-methane-disulfonic acid salt exerts a mild tanning action on the glue, thereby rendering it less responsive to the action of aluminum salts, and further giving it improved emulsifying and stabilizing properties, This view is advanced, because according to our observations:

(1) Only a relatively small amount, 0.8 to 3.2% DMDS based on the weight of the glue, gives the improved stability, and higher amounts are actually deleterious;

(2) The disulfonate must be added to the glue solution before the latter has made contact with the aluminum salts.

This invention has the following practical advantages:

The water-repellent compositions prepared have exceptionally high stability in storage, and remain unchanged in wooden or glass containers for a period of at least six months.

The water-repellent compositions prepared have exceptionally high stability in application to textiles by impregnation with a padding mangle or quetsch at temperatures ranging from 80 F.- 180 F. There is no tendency for the dispersions to coagulate and cause spotting of the goods when applied at high speed under all possible practical mill conditions.

The said high degree of stability is obtained while maintaining the property of imparting a liilgh degree of repellency on application to text es.

The use of the dinaphthyi-methane-disulfonic acid for pretreating the glue renders the glue resistant to degradation by the aluminum salts during manufacture of the water-repellent composition. As a result, all components may be mixed together before homogenization to obtain highly stable products even though the processing time is as long as four hours. It is not necessary to resort to closely controlled stepwise additions of the aluminum salt to obtain a uniformly satisfactory product in manufacture.

We claim as our invention:

1. In the process of producing a composition of matter comprising an emulsion of a paraffin wax in an aqueous solution of an aluminum salt selected from the group consisting of normal and basic aluminum acetates and formates, and a protective colloid selected from the group consisting of glue and gelatin, the improvement which consists of protecting the colloid against the action of said aluminum salt by treating said protective colloid with a tanning agent consisting of a water-soluble salt of dinaphthyl-methane-disulfonic acid prior to admixing the aluminum salt.

2. A process as in claim 1, wherein the quantity of said tanning agent employed does not exceed 312% based on the weight of the protective colloid.

3. The proces of preparing a Water-repellency agent in the form of a stable, aqueous emulsion, which comprises first adding to an aqueous solution of a protective colloid selected from the group consisting of glue and gelatin, a watersoluble salt of dinaphthyl-methanedisulfonic acid in a quantity not less than 0.8% and not more than 3.2% by weight of said protective colloid, and then using the resulting solution to emulsify a molten wax in the presence of an aluminum salt; said wax being selected from the group consisting of paraffin wax and mixtures of a paraffin wax with an ester type wax, while said aluminum salt is selected from the group consisting of normal and basic aluminum acetates and formates.

4. The process of preparing a water-repellency composition of matter in the form of a stable, aqueous emulsion, which comprises dissolving 1 part of glue in about 6 to 9 parts of water; addme to this solution from 0.008 to 0.032 parts of an alkali-metal salt of dinaphthyl-methane-disulfonic acid; then adding an aqueous solution of about 0.75 to 1.5 parts of an aluminum salt selected from the group consisting of normal and basic aluminum acetates and formates, and emulsifying into the resulting aqueous mass a molten wax mixture comprising refined paraflin wax and beeswax, the quantity of wax selected being sufficient to form an emulsion containing from 10 to 40% of total wax by weight.

oms:

5. A water-repellenoy composition of .matter comprising a stable aqueous emulsion of the following ingredients by percentage weight:

said modified protective colloid being a. complex organic compound obtained by reacting 100 parts o! a protective colloid irom the group consisting of glue and gelatin with from 0.8 to 3.2 parts of a water-soluble salt of dinaphthyl-methane-disuli'onic acid.

JOSEPH EDWARD SMITH. PAUL JONES MITCHELL, Jn.