US3321339A - Galvanizing flux - Google Patents

Description

United States Patent 3,321,339 GALVANIZING FLUX William A. Schulze, Parma Heights, Ohio, assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed May 7, 1965, Ser. No. 454,211 6 Claims. (Cl. 148-23) This invention relates to the galvanizing fluxes and is more particularly directed to compositions adapted to be used in a flux wash consisting essentially of a fluxing material such as zinc ammonium chloride modified with an alkyl sulfonate and the condensation product of oleyl alcohol with ethylene oxide.

It is customary to prepare metals prior to galvanizing and prior to introduction into a molten metal bath by passing them through an aqueous solution which is called a flux wash. Such solutions customarily contain fluxing materials such as zinc chloride, ammonium chloride, and zinc ammonium chloride.

It is important, especially in some of the new high-speed continuous galvanizing processes, that the flux wash thoroughly wet the surface of the metal and yet the solution must not foam excessively. If there is any considerable foaming in the flux wash, the high speeds at which the metal is traveling cause an excessive dragout from the flux wash bath. When foam is carried out 7 on the metal this gives a very uneven layer of flux thickness and as the foam breaks there are thin spots which result in poor galvanizing.

It has been proposed in Speed et al. US. Patent 2,879,195 that excessive drag-out be diminished by the use of an alkyl sulfonate. Such fluxes have been used commercially with success. However there is often a greasy dispersed phase which separates and rises to form an oily scum. This greasy material is quite objectionable and will often collect into waxy agglomerates of considerable size which float on the surface of the flux and interfere with galvanizing. Metallic hydroxides also tend to be gathered into the waxy agglomerate and this further interferes with galvanizing.

As described in Speed US. Patent 2,829,077 a similar effort Was made to solve the problem of excessive dragout by using a condensation product of oleyl alcohol with ethylene oxide. Flux washes containing this material were comparable in activity to those of the Speed Patent 2,879,195 but had a somewhat greater tendency to form a foam. Accordingly they are less attractive commercially.

Now I have found that by using a small amount of a condensation product of oleyl alcohol with ethylene oxide as shown in Speed 2,829,077 in the flux wash compositions of 2,879,195 there are obtained flux washes which are substantially free of the dispersed insoluble oily materials which eventually form scum and interfere with operation of the fluxes of Speed 2,879,195. Flux washes as thus modified do not gather metallic hydroxides into a Waxy mass but rather the metallic hydroxides settle to the bottom of a tank containing the flux wash from which they can readily be separated. Flux washes containing both the alkyl sulfonate and the oleyl ethylene oxide condensation product are very low foaming, stable in use, and are homogeneous solutions.

The improved flux wash compositions of this invention can be prepared with a fiuxing material such as ammonium chloride, zinc chloride, zinc ammonium chloride, and other such flux compositions. Most preferred for flux wash compositions of the invention are the socalled high ratio zinc ammonium chlorides. These are flux compositions in which the weight ratio of ice ranges from 1.27:1 to 1.35:1. These are normally made up into prewash fluxes of about 12.2 Baum strength and used at temperatures around F.

The prewash flux compositions of the invention are made up by the addition to one of the flux materials described, and preferably to a high ratio zinc ammonium chloride, of a small amount of an alkyl sulfonate. The alkyl sulfonate has the formula:

in which R is a higher alkyl group ranging from about 8 to 18 carbon atoms.

The commercially available material which is preferred contains minor amounts of sodium sulfate and sodium chloride and R is approximately C which corresponds to the kerosene fraction. The SO Na groups are randomly distributed. A preferred range of commercially available materials are those made from a hydrocarbon fraction of 12 carbons to a fraction which is about 16 carbons.

As described above, the composition containing an alkyl sulfonate is modified by the inclusion of a copolymerization product of oleyl alcohol with ethylene oxide. The oleyl alcohol used is preferably the technical grade which is a mixture of saturated and unsaturated alcohols ranging from about '8 to 22 carbon atoms and prepared by the sodium reduction of a suitable oil such as, preferably, sperm oil.

The oleyl alcohol is reacted with ethylene oxide as shown in Schoeller and Wittwer US. Patent 1,970,578, dated Aug. 21, 1934. About 10 mols of ethylene oxide are used for each mol of oleyl alcohol. This can obviously vary somewhat, say, from 8 to 12 mols, though it is preferred to use 10 mols.

In making flux compositions of the invention the alkyl sulfonate and the oleyl alcohol-ethylene oxide condensation product can be mixed together and the mixture applied to the dry flux material if it is to be sold in dry form. The materials can of course be added separately if more convenient. The sulfonate is commercially available as a 20% solution in water and the oleyl alcohol condensation product is a waxy material which can be dissolved in the solution if it is wished to add them together. It is somewhat preferred that the materials be thus mixed and then added together because there is a tendency for the oleyl alcohol condensation product to gel and this is prevented.

The flux materials are frequently sold as aqueous solutions and in this event the additives can simply be dissolved in a solution of the material. Thus high ratio zinc ammonium chloride is customarily sold as a 58% solution in water and the mixture prepared as above is preferably added to this solution.

The amount of the alkyl sulfonate to be used can be varied widely depending upon the flux material and upon the effect desired. Generally there will be used from about 0.04 to 0.4 gram, computed as sodium salt, of alkyl sulfonate per hundred gram of zinc ammonium chloride or of the other fluxes mentioned. Less than this does not have the desired magnitude of effect and the use of more is wasteful.

The alkyl sulfonates are sold commercially as the sodium salt and when reference is made herein to the use of an alkyl sulfonate this can conveniently be the sodium salt or if desired a potassium salt or another soluble salt. The products can of course be used as the alkyl sulfonate without forming the salt and all can be considered as equivalent for purposes of the present invention.

The amount of the oleyl alcohol-ethylene oxide condensation product depends upon the amount of the alkyl sulfonate. Broadly, the proportion is such that the ratio of alkyl sulfonate:oleyl condensation ranges from 0.2:1

to 4: 1. More narrowly it is preferred that the ratio range from 1:1 to 2:1 in commercial practice.

When reference is made in the claims to a galvanizing flux it will be understood that this can be dry, can be a concentrate suitable for dilution to form a flux Wash at the place of use, or can be the dilute flux wash at a concentration suitable for use.

In order that the invention may be better understood reference should be had to the following illustrative examples:

Example 1 Four parts by weight of an alkyl sulfonate was placed in a receptacle in the form of a 20% solution in water. The alkyl sulfonate contains sulfonates of the formula in which the SO Na groups were randomly distributed and in which R approximates C (kerosene). The product contained minor amounts of sodium sulfate and sodium chloride as well as a small amount of unreacted alkane. It was used as the sodium salt.

To the aqueous solution there was added two parts by weight of melted condensation product of ethylene oxide with oleyl alcohol. The oleyl alcohol used is a mixture of saturated and unsaturated alcohols of 8 to 22 carbon atoms. This is sold commercially as technical oleyl alcohol. The technical grade oleyl alcohol was a mixture of saturated and unsaturated alcohols obtained by the sodium reduction of sperm oil and had the following approximate composition:

Percent C saturated 3.23 C unsaturated 2.87 C saturated 12.55 C unsaturated 19.65 C saturated 7.7 C unsaturated 42.8

C saturated C unsaturated 7.1 C saturated 0 C unsaturated 4.1

The oleyl alcohol was reacted with mols of ethylene oxide for each mol of alcohol as shown in Us. Patent 1,970,578.

The two materials were mixed to form a clear solution. The six pounds of material was then dissolved in a 58% aqueous solution of zinc ammonium chloride which contained 10,000 pounds of the zinc ammonium chloride. The zinc ammonium chloride had a ZnCl zNH Cl ratio of 13:1.

The product thus produced is clear and substantially free from dispersed insoluble material. Any precipitate of metal oxides or hydroxides separates to the bottom. The solution as thus prepared can be sold as a flux wash concentrate and a customer will use it by adding water in the amount desired, usually about an equal quantity depending upon the customers preference. The flux wash thus prepared can be used in the customary manner and gives excellent results with negligible foaming and with even galvanizing of excellent quality.

The ratio of the sulfonate to the oleyl-ethylene oxide condensation product is 2:1 in the above example.

zinc ammonium chloride can be 0.4 or any intermediate figure with the ratio of sulfonate to oleyl condensate being 0.2:1, l: 1, 2:1, 4:1 or any intermediate figure. Likewise the zinc ammonium chloride used above can be replaced in each of the possibilities described with zinc ammonium chloride of a diiferent ratio or with ammonium chloride or zinc chloride.

Example 2 A 20% solution of the alkyl sulfonate of Example 1 in an amount to contain 4 parts by Weight of sodium salt of alkyl sulfonate was used to dissolve 2 parts by weight of a condensation product of oleyl alcohol with ethylene oxide as in Example 1. The mixture is then sprayed upon 10,000 pounds of zinc ammonium chloride, the zinc ammonium chloride having a ratio as described in Example 1.

A similar procedure can be followed with the same components but simply mixing the zinc ammonium chloride and the wetting agent by dumping them into the hopper of a mixing screw in which thorough mixing is effected.

I claim:

1. A galvanizing flux consisting essentially of a fluxing material selected from the group consisting of ammonium chloride, zinc chloride, and znc ammonium chloride and 0.04 to 0.4 gram, computed as sodium salt of an alkyl sulfonate per grams of said fluxing material and the condensation product of oleyl alcohol with about 10 mols of ethylene oxide the ratio of said sulfonate to said oleyl alcohol condensation product being from 0.211 to 4:1.

2. A galvanizing flux of claim 1 in which the fluxing material is zinc ammonium chloride.

3. A flux composition of claim 2 in which the ZnCl :NH C1 weight ratio is 1.27:1 to 1.35:1.

4. A galvanizing flux for use as a high-speed continuous galvanizing flux wash consisting essentially of zinc ammonium chloride with a ZnCl :NH Cl weight ratio of from about 1.27:1 to 1:35:l and from about 0.04 to 0.4 gram per hundred grams of zinc ammonium chloride, computed as sodium salt, of an alkyl sulfonate in which the alkyl groups average about 13 carbon atoms and the condensation product of oleyl alcohol with about 10 mols of ethylene oxide, the ratio of said sulfonate to said oleyl alcohol condensation product being from 0.2:1 to 4:1.

5. A composition of claim 4 in which the oleyl alcohol is a technical oleyl alcohol containing alcohols ranging from 8 to 22 carbon atoms.

6. A composition of claim 4 in which the said ratio is 1:1 to 2:1.

No references cited.

DAVID L. RECK, Primary Examiner.

H. F. SAITO, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTHHCATE(HTCORRECTHMN Patent No. 3,321,339 May 23, 1967 William A. Schulze It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 33, for "znc" read zinc line 34, for "salt of" read salt, of line 47, for "1:35zl" read 1.35:1

Signed and sealed this 9th day of January 1968.

(SEAL) Attest:

EDUUU)J.BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

Claims (1)

1. A GALVANIZING FLUX CONSISTING ESSENTIALLY OF A FLUXING MATERIAL SELECTED FROM THE GROUP CONSISTING OF AMMONIUM CHLORIDE, ZINC CHLORIDE, AND ZNC AMMONIUM CHLORIDE AND 0.04 TO 0.4 GRAM, COMPUTED AS SODIUM SALT OF AN ALKYL SULFONATE PER 100 GRAMS OF SAID FLUXING MATERIAL AND THE CONDENSATION PRODUCT OF OLEYL ALCOHOL WITH ABOUT 10 MOLS OF ETHYLENE OXIDE THE RATIO OF SAID SULFONATE TO SAID OLEYL ALCOHOL CONDENSATION PRODUCT BEING FROM 0.2:1 TO 4:1.