US3265514A - Process for the manufacture of substances having porous structure - Google Patents

Description

United States Patent Claims. (Cl. 106-122) The present application is a continuation-in-part application of application Serial No. 846,261 filed October 14, 1959, now abandoned. v

Organic hydrophobing agents which can be applied in the form of solutions inorganic solvents have attained steadily increasing importance in industry because they permit re-impart-ing water-repelling properties to clothing made of leather, or particularly of textile material, which has been cleaned with organic solvents. The extensive application of this hydrophobing method is due to the various disadvantages involved in the formerly used aqueous re-hydrophobing. Thus, for example, the water used in aqueous re-hydrophobing causes the clothing to swell, and the dragging or shrinking of the materials cause deformations which can be repaired only, if at all, by ironing. Further, the time necessary for the aqueous hydrophobing baths, which in most cases are applied in the form of emulsions, to penetrate into the clothing is much longer than that of solutions of the agents in organic solvents; the same is true of the drying time after impregnation. 'In addition thereto it is only possible to achieve the same hydrophobing effect on goods made water-repellent in an aqueous medium by after-heating them to an elevated temperature; in consequence thereof, the goods made Water-repellent in such a manner are much more liable to creasing. Furthermore, the handle of goods made water-repellent in organic solvents is softer and more agreeable, since the protective colloids, for example such as glue, the use of which is necessary when applying aqueous hydrophobing agents, cause a hard handle (cf. Monheim, Farber-Zeitung Der F'airber und Chemischreiniger, volume 6, No. 11, Nov. 1953, pages 1-3).

As solid, organic hydrophobing agents that are suitable for these purposes, there are now also used particularly the alcoholates of polyvalent metals, such,'for example, as aluminum, zirconium and titanium. In most cases they are applied in a form which can be more or less reacted in a known way with about 0.1 to 3 moles of monobasic organic substances of acid nature, such, for example, as carboxylic acids or their anhydrides, like formic or'acetic or propionic acid, caprylic acid, lauric acid, myristic acid, aromatic monocarboxylic acids, monosulfinic acids, monosulfonic acids, phosphonic acids, or organic monosulfuric acid or phosphoric acid esters, particularly fatty acids of high molecular weight, such for example, as stearic or oleic or palmitic acid, as well as metal-alcoholates branched by metal-oxygen linkages.

In this regard are mentioned as examples the semior mono-stearates of aluminum ethanolate or isopropylate or sec. butanolate or amylate or hexanolate or '2-ethyl hexanolate, or the corresponding Ti or Zr compounds, which, in addition, may be partially reacted in known way with about 0.1 to 3 mols of keto-enol compounds, such, for example, as aceto-acetic ester, like methyl, ethyl, isopropyl, butyl, amyl esters, or aliphatic ,B-diketones like acetyl-acetone, 2,4-diketo-hexane or 3,5-diketo-octane, or malonic acid dimethyl ester or diethyl ester or dibutyl ester, to prevent early decomposition by humidity, or with neutral salts of the metals mentioned above with lower or higher carboxylic acids, for example, aluminum-diacetate-monostearate. Such organic hydrophobing agents are described, for example, in German Patent 968,936, in German patent specifications 1,004,585, 1,025,824, and 1,039,991, in US. Patents 2,838,422, 2,877,248, and 2,801,190, in Italian Patent 555,656, and in published German patent application No. 18,338 IVc/ 8k.

Lesser water-repelling effects are produced by the known, basic, hydroxy-group-containing salts of polyvalent metals, for example basic aluminum-distearate, by fatty acid anhydrides, or fatty acid methylol amides, or N,N'-ethy1ene ureas, for example, hexadecyl-N-ethylene urea, or copolymers of maleic acid, or their esters with vinyl ethers of higher molecular weight, such as octadecylvinyl ether or derivatives of polymethylolaminoor polyaZirino-triazines containing aliphatic radicals of higher molecular weight, for example, the lauric or stearic acid radical.

These organic hydrophobing'agents are used together with about 0.5-3 parts by weight of paraffin which mostly has an average solidification point of about 40l00 C., more particularly 60 C., but rarely with parafiin slack waxes or waxes, because the hydrophobing is considerably improved despite the fact that the parafiins alone have only a poor hydrophobing effect. Even oily, organic hydrophobing agents, for example, known aliphatic isocyanates of higher molecular weight, such, for example, as ocetadecyl isocyanate, namely in a form solidified by paraffin, enter into consideration.

In general, these mixtures of hydrophobing agents have a*solid, or more seldom a semisolid consistency. The massive, compact form is inappropriate for easy manipulation by the consumer when measuring small amounts, since at ordinary temperature it can only be comminuted with the aid of crushing tools; a solvent-free product in shred-likeor powder-like form, on the other hand, is liable 'to cake together particularly at summer temperatures. For these reasons, these mixtures of hydrophobing agents are marketed in admixture with about equal parts of the solvents used for the impregnation bath, in particular White spirit and perchlorethylene, that is in the form of a body which at ordinary temperature is grease-like and cuttable. These preparations, however, have many disadvantages in practice. Thus, evaporation of the solvent 7 often causes changes of the concentration of the solvent as well as incrustations at the walls of the containers. Already in mild heat the product looses its homogeneity because of partial melting of the solid components. Furthermore, the solvents used also involve many risks, for example, of intoxication and flammability. Moreover, the preparations that contain solvents have a higher transport weight than the solvent-free preparation. Weighing and measuring at ordinary temperature can be carried out incorrectly only. At lower temperatures, it is necessary to melt the products before measuring, which on the one hand, consumes time, and on the other hand, leads to incorrect doses when the products are inhomogenous due to incomplete melting. Storage of the products is often complicated by the fact that each solvent requires a specific greasy consistency. Finally, the greasy consistency also causes inconvenient, additional work since any spilled product cannot be swept up, but must be wiped away.

Now, we "have found that the aforesaid hydrophobing agents for use in organic solvents can be given a new, solid, porous consistency, which renders them easily manip-ulable and avoids the disadvantages described, by introducing an inert gas or air into the said solid organic hydrophobing agents, in a fused state .at a temperature above the solidification point, and cooling the products in this foamy state, having a specific gravity of about to about 33% of the gravity of the fused state of the hydrophobing agent, until solidification occurs. These organic hydrophobing agents agents contain paraifin and are solidified by addition of paraflin; they do not contain water, emulsifiers, foam stabilizers or Waxes; they contain the aforesaid aluminum, zirconium or titanium compounds and. are soluble in low or medium-boiling aliphatic or chlorinated aliphatic hydrocarbons, or aromatic or chlorinated aromatic hydrocarbons. The aliphatic or aromatic or chlorinated hydrocarbons mentioned comprise, for example, benzine, white spirit, carbon tetrachloride, trichlorethylene, perchlorethylene, toluene, chlorobenzene or mixtures of these solvents.

If such a foamy-porous melt is emptied into buckets, casks or lined bags, the porous mass, after solidification, can easily be cut out by hand at ordinary temperature without using crushing tools as is necessary with massive products and in the same manner as the solventcontaining grease-like mixture; when very cold, the products according to this inventon can be cut even more easily than can a grease, since the solvent-containing grease solidifies to a compact, wax-like mass. Weighing manipulations can be carried out--even in moderate heat, cleanly and conveniently. The transport weight of these hydrophobing agents is low due to the economy of weight attained by the omission of the solvent. Neither inflammable nor toxic vapors are formed, so that protective measures can be dispensed with.

Storage is simplified since the products according to this invention can be used generally in all the solvents used in practice. If the melt according to this invention is allowed to solidify to form sheets, the latter can be cut up more easily than massive sheets. Semi-solid, organic, hydrophobing agents in porous form have a better coherence and incline less to stringing and running, which improves their homogeneity, in particular at mild heat during transport.

Although it is valuable with regard to application that solvents are absent, the process of the present invention can be carried out also in the presence of small additions of organic solvents of about 0.0110%, like lower aliphatic alcohols, hydrocarbons like white spirit or toluene, chlorinated hydrocarbons like perchlor-ethylene or mixtures of these solvents; in this case, the solidified, porous consistency of the product offers the advantage of a smaller amount of solvent difllusing through the surface, thus reducing the risks of ignition and intoxication.

The porous form according to the present invention offers unexpected advantages on subsequent dissolving in solvents, since We have found that the solidified, porous, hydrophobing agents dissolve at ordinary temperature faster than the same quantity by weight of the massive and the corresponding amount of the grease-like forms. The solidified pore structure according to this invention, which at a temperature just below the melting point still has improved the coherence and homogeneity, is much more quickly decomposed by the action of organic solvents than the wax-like greasy structure of the hitherto used solvent mixtures.

The incorporation of the gas pores, the quantity of which may be so adjusted as to lower the specific gravity of the products to about 95 to 33 percent, preferably to 80 to 50 percent of the specific gravity of the hydrophobing agent in the fused state, and the size of which may range between 0.1 mm. and 5 mm., preferably /2 mm. and 1 mm., can be effected in various ways. The organic hydrophobing agent, as mixtures thereof with parafiin, may first be melted. Inert gases, for example air, carbon dioxide, or nitrogen may then be introduced into the melt, through frits forexample, particularly when the melt is at a temperature near the dropping point. The gases may be introduced under pressure, and the melt is preferably stirred, for example with Archimedean stirring device such as crutchers. Alternatively, gas-forming materials such as inorganic or organic substances, soluble in organic solvents and yielding carbon dioxide or nitrogen, may be added to the melt. The hot, foamy, but still pourable or movable melt is then, if necessary underreduced pressure, caused to solidify to an appropriate solid form in, for example, buckets, bags or casks. These solidified .porous masses can be more easily cut out from the containers with scoops, or comminuted than can a massive solidified product.

In order to facilitate easier dosing on dissolving, it is advantageous to make up the hydrophobing agent in the form of scored sheets of a weight commonly used com mercially. For transport, such sheets can be packed, for example, in, foils used commercially for such purposes and made of, for example, regenerated cellulose, and they can be enclosed in bags or rectangular containers made of paperboard or wood, for example, cardboard boxes or cases, without sweating through occurring even just below the melting point.

The foamy, if desired more or less solid melt may also be processed into other forms. For example, it can be extruded and cut into chips or flakes or into bodies of cylindrical or angular section or in :balls. The foamy melt may also be converted into chips or scales or slack. For this purpose it is continuously supplied in a thin layer to a rotating roll, which is cooled from the interior and, after solidification, it is continuously scraped oif from the cooling roll by means of a knife. Solid to hard parafiins and a low degree of foaming are suitable therefor, the density of the melt being reduced by about one tenth to one third. The scales are prepared in a manner analogous to the preparation of NaOH scales described by Kirk-Othmer in Encyclopedia of Chemical Technology, volume I, page 425, paragraph 3.

Even semi-solid mixtures of the hydrophobing agents that contain, if desired, small additions of solvents, can be provided with gas bubbles, for example, in molten state, and then cooled in, for example, buckets or cups, to solidify partially into a foamy-creamy form. This consistency also has the advantage that it can be cut out more easily'and more cleanly from the containers, for example, buckets or cups than the pore-free mass, and that it dissolves faster in organic solvents.

It has already been proposed to prepare opaque parafiin for the manufacture of waxworks, in particular candles, by stirring finely distributed air bubbles into the melt without having to add clouding agents, and, since these parafiin melts easily give off these gas bubbles, it has also already been proposed to add to these melts foam stabilizers such as alkali salts of anion-active detergents, or rn'icrocrystalline Waxes (US. Patent 2,185,046, US. Patent 2,583,938; Seifen-Ole-Fette-Wachse (1957), page 749). There could, however, not be drawn any conclusions therefrom on the behaviour of water-free and emulsifier-free paraffin-containing melts of strongly hydrophobic organic hydrophobing agents in the absence of foam stabilizers, because these hydrophobing agents are not waxes, neither chemically nor physically, e.g. inter alia they are not polishable and form strings at temperatures above the melting point. On the contrary, it had to be feared that these products would considerably more reluctantly incorporate gas bubbles than the melts of the paraffin which is only slightly hydrophobic. These publications do not disclose any statements on the behaviour of'the products concerned towards organic solvents.

The following examples serve to illustrate the invention but they are not intended to limit it thereto.

Example 1 Into 10 kg. of a molten mixture (Ubbelohde-flowing point 56 C., dropping point 57 C.) consisting of 7 kg. of parafiin (softening point 55 C.), 2.5 kg. of the monostear a-te or mono-oleate of aluminum ethanolate and con tact paraflin (softening point C.), there is introduced air at about 53 C. by means of a frit and while stirring, for so long a period until a solidified sample of the creamy melt shows a specific gravity of 0.60 (instead of originally 0.87). The foamy melt is then poured to form rectangular sheets weighing 1 kg., having a size of 20 X 2.8 cm. and containing in regular distribution grooves for easier partition. Rectangular portions thereof having 20 X 6 x 2.8 cm. in size and 200 g. in weight, dissolve in 5 liters of perchlorethylene, while stirring, and at 30 C. within about 30 minutes, whereas massive portions having the same weight and a size of 20 x 4 X 2.8 cm., of the same but pore-free mixture are dissolved under otherwise equal conditions after about 200-220 minutes.

At about 20 C., the porous portions are dissolved after about 50 minutes, whereas the massive portions are dissolved after about 300 minutes; rectangular, solventcontaining, grease-like portions having a size of 20 X 6.3 X 2.8 cm., 400 g. in weight and containing 50 percent by weight of perchlorethylene, require about 100 minutes to dissolve.

If instead of the monostearate of aluminum-ethanolate the same amount of aluminum-diacetate-monopalmitate or monolauric titaniumor zirc'onium-butanolate or octadecyl-isocyanate or the reaction product of 1 mol of stearic acid and pentamethylol-melamine-pentarnethyl ether is used, similar results are obtained.

If one of the above described foamy melts is allowed to solidify in buckets having a capacity of liters, the porous filling mass can be cut out at about 30 C. with a scoop and dissolved in white spirit or carbon tetra chloride equally well as a similar pasty, pore-free mass prepared with a part by weight of perchlorethylene.

If, however, a pore-free melt of the same mixture of substances is allowed to solidify in similar buckets, the mass can be comrninuted with crushing tools only or must be melted down, which is very time consuming due to the low thermal conductivity of the mixture. During the melting of grease-like, solvent-containing mixtures, a large part of solvent evaporates whereby disadvantageous changes in concentrations are caused, and odors or flammable vapors may be generated.

Example 2 Into the melt of 10 kg. of paraffin and 10 kg. of distearate of aluminum sec.-butanolate prepared according to German Patent 569,946, nitrogen is introduced at 90 C. and with intensive stirring, by means of a frit until the volume has increased by A and the specific gravity has decreased to 90% of the initial melt. The foamy melt is then emptied on plates or into buckets provided with bars. The resulting porous form is more easily dissolved than the corresponding pore-free form.

The foamy melt of Examples 1 and 2 may be continuously supplied in a thin layer to a rotating roll which is cooled from the interior. From this roll, the solidified mass can be scraped off whereby it falls down in the form of scales and chips which are more rapidly soluble in perchlor-ethylene or white spirit at normal temperature than scales or chips free from pores.

Example 3 100 kg. of a mixture (Ubbelohde flowing point 55 C., dropping point 56 C.), that has been melted at 60 C., of 70 kg. of paraffin (softening point 54 C.) and 25 kg. of stearic aluminum-isopropanolate prepared from 0.8 mol of stearic acid (softening point 65 C.), 0.4 mol of aoeto-acetic acid ester and 1 mol of aluminum-isopropanolate, are stirred by means of a high speed anchorshaped stirrer (150 revolutions per minute) which revolves close by the wall of a 250 l. stirring vessel. Water at 45 C. is circulated through a cooling mantle. Upon cooling of the melt from 60 C. to 54 C., while stirring continuously, only a few foam bubbles appear at the surface of the melt. When the temperature of the melt is then allowed to fall within one hour to 52 C., fine porous foam distributes uniformly in the melt, the volume of which rises by about /3. Simultaneously small sized solidified portions distribute uniformly in the melt. A sample of the foamy, but still mostly oily mass shows a specific gravity of 0.53, whereas a massive, solidified sample taken at the beginning shows a specific gravity of 0.88. By introducing nitrogen, at about 5l-52 C. and while continuously stirring, into the melt by means of a tube provided with frit-like openings, the volume can be conveniently increased. The introduction of gas and stirring are discontinued when a sample of the foamy mass shows a specific gravity of 0.40.

The still thickly liquid foam is then discharged, while continuing stirring and at temperatures closely below the solidification point, into suitable forms, for example, in boxes that are higher than they are broad, such as corrugated paperboard folding boxes. The size of these boxes is advantageously selected so that the thickness of the sheets obtained permits cutting them by hand with a knife. Boxes having, for example, the size of 400 X 500 X 125 mm. are suitable. Such boxes of 25 liters capacity give sheets weighing 10 kg. To permit easy partition of the sheets, without weighing, into portions each weighing 2 kg, horizontal divider pads can be inserted in the boxes, which pads are elevated toward the interior, for example, 4 pads in intervals of 100 mm. If the sheets are to be shipped at elevated temperatures a suitable bag, for example made of polyethylene, .acetyl cellulose or cellulose glass foil, can be inserted into the boxes before filling.

Chips or scales of about 0.1-5 g. can be planed off with a planing machine from the solidified sheets of the porous hydrophobing agents of Examples 1-3. These porous chips or scales are more rapidly soluble than chips or scales free from pores planed off from passive sheets of the hydrophobing agents.

We claim:

1. The method of making .a shaped solid-foam 'body adaptable to solution in organic solvents to form textile hydrophobing solutions, which method comprises forming .a melt of an anhydrous hydrophobing agent consisting essentially of (a) 0.5 to 3 parts by weight of paraflin having a solidification point of from 40 to 100 C., (b) one part by weight of a member selected from the group consisting of (1) aluminum, ziconium, and titanium alcoholates of aliphatic alcohols having 2 to 8 carbon atoms, (2) said alcoholates reacted with from 0.1 to 3 mols of a monocarboxylic aliphatic acid per mol of alcoholate, said acid having 1 to 18 carbon atoms, and (3) the compounds of groups 1) and (2) reacted with from 0.1 to 3 mols of an aliphatic keto-enol per mol of compound, and (c) 0.01 to 10 percent, of the combined weight of (a) and (b), of an organic solvent selected from the group consisting of a lower aliphatic alcohol, toluene, perchloroethylene, white spirits, and mixtures thereof, dispersing an inert gas in said melt in amounts sufficient to produce a fluid foamed melt having a specific gravity about to 33% that of the specific gravity of the unfoamed melt, casting said fluid foamed melt to foam said shaped body, and cooling the cast melt to its solidification point.

2. The method as in claim 1 wherein said inert gas is dispersed in said melt 'by blowing said gas into the melt while stirring.

3. The method as in claim 1 wherein air is dispersed in said melt by vigorously stirring said melt.

4. The method as in claim 1, wherein the inert gas is air.

5. The method as in claim 1, wherein the inert gas is carbon dioxide.

6. The method as in claim 1, wherein the inert gas is nitrogen.

7. The method as in claim 1 wherein said hydrophobing agent is stabilized with an acetoacetic ester.

8. The method as in claim 1 wherein said melt of hydrophobing agent is vigorously mixed with inert gas such that the specific gravity of the resulting solid foamed body is from 8050 percent of the specific gravity of the hydrophobing agent melted.

9. The method as in claim 1 wherein said melt of hydrophobing agent and inert gas are vigorously mixed with the melt at a temperature up to 4 C. above its dropping point.

10. The method as in claim 1 wherein shaped bodies particularly suitable for convenient commercial use are prepared by casting said foamed melt into a plurality of plastic-film bags contained within a carton.

References Cited by the Examiner UNITED STATES PATENTS 2,456,595 12/1948 Rood 106-270 2,628,170 2/1953 Green 106270 2,892,732 6/1959 Rockland 106-271 ALEXANDER H. BRODMERKEL, Primary Examiner.

D. I. ARNOLD, Assistant Examiner.

Claims (1)

1. THE METHOD OF MAKING A SHAPED SOLID-FOAM BODY ADAPTABLE TO SOLUTION OF ORGANIC SOLVENTS TO FORM TESTILE HYDROPHOBING SOLUTIONS, WHICH METHOD COMPRISES FORMING A MELT OF AN ANHYDROUS HYDROPHOBING AGENT CONSISTING ESSENTIALLY OF (A) 0.5 TO 3 PARTS BY WEIGHT OF PARAFFIN HAVING SOLIDIFICATION POINT OF FROM 40* TO 100*C., (B) ONE PART OF WEIGHT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF (1) ALUMINUM, ZICONIUM, AND TITANIUM ALCOHOLATES OF ALIPHATIC ALCOHOLS HAVING 2 TO 8 CARBON ATOMS, (2) SAID ALCOHOLATES RECTED WITH FROM 0.1 TO 3 MOLS OF A MONOCARBOXYLIC ALIPHATIC ACID PER MOL OF ALCOHOLATE, SAID ACID HAVING 1 TO 18 CARBON ATOMS, AND (3) THE COMPOUNDS OF GROUPS (1) AND (2) REACTED WITH FROM 0.1 TO 3 MOLS OF AN ALIPHATIC KETO-ENOL PER MOL OF COMPOUND, AND (C) 0.01 TO 10 PERCENT, OF THE COMBINED WEIGHT OF (A) AND (B), OF AN ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF LOWER ALIPHATIC ALCOHOL, TOLUENE, PERCHLOROETHYLENE, WHITE SPIRITS, AND MIXTURES THEREOF, DISPERSING AN INERT GAS IN SAID MELT IN AMOUNTS SUFFICIENT TO PRODUCE A FLUID FOAMED MELT HAVING SPECIFIC GRAVITY ABOUT 95% TO 33% THAT THE SPECIFIC GRAVITY OF THE UNFOAMED MELT, CASTING SAID FLUID FOAMED MELT TO FOAM SAID SHAPED BODY, AND COOLING THE CAST MELT TO ITS SOLIDIFICATION POINT.