AU621980B2

AU621980B2 - Water soluble salt precoats for wire drawing

Info

Publication number: AU621980B2
Application number: AU49209/90A
Authority: AU
Inventors: Thomas W. Tull
Original assignee: Henkel Corp
Current assignee: Henkel Corp
Priority date: 1989-02-07
Filing date: 1990-02-07
Publication date: 1992-03-26
Anticipated expiration: 2010-02-07
Also published as: AU4920990A; DE69002649T2; DE69002649D1; CN1044774A; EP0382155B1; EP0382155A1; BR9000543A; DK0382155T3; ATE92951T1; ES2059847T3; ZA90917B; JPH02229893A; CA2009377A1

Abstract

A composition for coating steel wire to facilitate the cold drawing thereof, said composition comprising: (A) from about 50 to about 99.99 % by weight of a component selected from the group consisting of Na2SO4, K2SO4, and mixtures thereof; (B) from about 0 to about 49.99 % by weight of a component selected from the group consisting of Na2B4O7, NaBO2, K2B4O7, KBO2 and mixtures of any two or more thereof; and (C) from about 0.01 to about 5 % by weight of a component selected from the group consisting of potassium soaps, sodium soaps, and ammonium soaps; wherein the percentages by weight are based on the total weight of components A, B, and C in the composition, and wherein not more than 50 % by weight of the total of sodium plus potassium plus ammonium ions in components A, B, and C of the composition consists of sodium ions.

Description

621929 Form COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: o" I't Published: 0 4Priority o t a 0 Rplated Art: o0 6 Name of Applicant HENKEL CORPORATION Address of Applicant: 300 Brookside Avenue, Ambler, Pennsylvania 19002, United States of America Actual Inventor: THOMAS W. TULL Address for Service WATERMARK PATENT TRADEMARK ATTORNEYS.

290 Burwood Road, Hawthorn, Victoria, Australia Complete Specification for the invention entitled: WATER SOLUBLE SALT PRECOATS FOR WIRE DRAWING The following statement is a full description of this invention, including the best method of performing it known to -i ii '1 h a 1, g t-:i i 1 i:? :i

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i ii t i: ii d Cross-reference to related application This application is a continuation of copending application Serial No. 307,643 filed February 1989.

BACKGROUND OF THE IHVENTION 1. Field of the Invention This invention relates to modified water soluble salt precoats for use In the cold drawing of steel wire.

2. Background of the Invention Water soluble salt coatings are often applied to steel wire in the form of aqueous solutions prior to drawing. The solution-coated wire Is dried and the resulting salt coated wire is then drawn through conventional reducing dies using dry soap lubricants a process well-known to this art. The water soluble salt coating acts as a lubricant carrier, pulling the dry soap box lubricant into the dies, thus providing lubrication. These driedin-place, water soluble salt coatings have proven to be superior to other conventional coatings such as lime or borax coatings because of their improved ability to carry lubricant into the dies. A typical soluble salt composition used for the coating of steel (usually stainless steel) wire contains both sodium sulfate and borax. Such soluble salt compositions provide coatings with excellent crystalline structure, resulting in good soap lubricant pick-up when the coated wire is passed through a soap box, and therefore good drawability. However, such salt coatings are prone i C-arx-n~i i I j i r I i i t i i i i ::i i to excessive moisture absorption upon exposure to ambient air, particularly when exposed to air having high humidity. Such moisture absorption seriously interferes with, or even prevents, the drawing of the coated wire. On the other hand, soluble salt coatings which provide low moisture absorption provide little or no crystalline structure amorphous or glaze type coatings) and are significantly inferior in both lubricant pick-up and drawability. This Hobson's choice problem has not previously been solved.

i iSTATEMENT OF THE INVENTION Other than in the operating examples, or where otherwise S° indicated, all numbers expressing quantities of ingredients or Oo.6 reaction conditions used herein are to be understood as modified 15 in all instances by the term "about".

Compositions for coating steel wire have now been discovered which provide uniform coatings with good crystalline structure, TI soap pick-up, and drawability, while at the same time low moisture absorption even during humid days, i.e. low hygroscopicity.

The compositions of the invention, which are in the form of *I dry mixtures prior to dilution with water for use, contain the following components: A. from 50 to 99.99, preferably from 70 to 89.9% by weight i| K2S04; B. from 0 to 49.99, preferably from 10 to 29.9% by weight I ^K 2 B40 7 and/or KB02; and I C. from 0.01 to 5, preferably from 0.1 to 1.0% by weight of an ammonium or potassium soap, wherein up to 50% by weight, and preferably no more than ji 30 by weight, of the total potassium ions and ammonium ions present in B. and C. can be replaced with sodium ions. More preferably, substantially none of the potassium and ammonium are replaced with sodium ions, since the more sodium ions present, the greater the hygroscopicity. When sodium ions are present, they can be present in one or more of components A., -2- L I e~.

0I I o *I I, I I I i itt B. and e.g. component C. can be partially or entirely a sodium soap. Also, component A. and/or B. can be a sodium or a potassium salt, or a mixture of such salts, provided the limitation on total quantity of sodium ion is maintained.

The fact that the above compositions provide good crystalli- -nity on steel wire is completely unexpected, since the above compositions without component C. give non-uniform coatings on steel wire which are not useful as such since both soap pick-up and drawability are unsatisfactory. In some unknown manner, the presence of the soap provides an at least partially crystalline uniform coating when the composition in aqueous solution is applied to the steel wire which is then dried or allowed to dry.

The K 2

SO

4 used as component A. can be chemically pure or of a technical grade; the latter being preferred due to cost con- 15 siderations.

The K 2

B

4 0 7 used as component B. can also be chemically pure or a technical grade, and is generally available and used herein as the tetrahydrate (K 2

B

4 0 7 -4H 2 Similarly, the KB0 2 which can be used alone as component B, or in a mixture with K 2

B

4 0 7 in any proportions, can be chemically pure or a technical grade.

The anmonium or potassium soap is one or more ammonium and/or potassium salts of a C 1 2

-C

2 2 fatty acid or mixture of two or more such C 1 2

-C

2 2 fatty acids. The fatty acids are generally saturated and unbranched, with ammonium or potassium stearate being pre- 25 ferred for use herein, although mono- or di-olefinically unsaturated C 1 2

-C

2 2 fatty acids can also be employed, either alone or in mixtures with each other and/or with saturated fatty acids. For example, ammonium and potassium soaps derived from the fatty acid mixtures obtained by the saponification of tallow oil or coconut 30 oil, or a mixture thereof, can advantageously be employed as component C. Also, ammonium or potassium salts of branched or cycloaliphatic-containing

C

1 2

-C

2 2 fatty acids can also be employed herein, either alone or in mixtures with unbranched fatty acid salts. Also, ammonium or potassium rosin acids, e.g. abietic acid, can also be employed as component C.

The wires coated with the coating compositions of the invention are generally steel wires, and usually stainless steel wires.

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ji However, other wire substrates can also be coated with the present coating compositions such as mild steel, titanium, vanadium, tungsten, aluminum, copper, nickel, zirconium, etc., and alloys thereof.

The coatings are applied by contacting the wires with an aqueous solution of the composition of the invention, and allowing the resulting wet coating to dry in place, either with or without the application of heat. The aqueous solutions generally contain from 75 to 400 g/l of the composition in water, preferably from 150 to 250 g/l.

The wire is contacted with the solution by any convenient technique, either batch or a continuous strand, and allowing the resulting wet-coated wire to air dry before coiling for storage, tiff shipping, or use. The coated wire is then passed through convenf 15 tional cold reduction equipment using a soap box containing a conventional dry soap lubricant). The coating on the wire functions as a carrier to carry the dry soap lubricant into the die.

The steps employed in the treatment of wire according to the invention include the following: 1. Cleaning the wire cleaning compositions are well-known in the art and do not comprise part of the present invention.

2. Rinsing with water.

25 3. Pickling here also, pickling compositions are wellknown and the selection of a pickling composition is not part of the invention.

4. Rinsing with water.

5. Applying the coating composition of the invention as 30 described above.

6. Drying the wire as described above to produce the coated wire of the invention.

The coated wire can then be drawn, also as described above.

The water used in preparing the aqueous solutions of the invention is preferably distilled or deionized water, but tap water can also be used provided it is not overly hard and has a low dissolved sodium salts content.

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I The invention will be illustrated but not limited by the Sfollowing examples.

EXAMPLES

EXAMPLE 1 The following aqueous compositions were tested for their morphology and hygroscopicity, when coated on stainless steel panels. Stainless steel panels were coated with each of the following compositions by immersing the panels in the aqueous composition, removing the panels from the aqueous composition, and allowing them to flash (air) dry.

a) 187.2 g of a mixture of 75 wgt Na 2 S0 4 and 25 wgt oo, sodium tetraborate10H 2 0 per liter of deionized water.

SUse temperature 190 0

F.

0900 b) 187.2 g of a mixture of 75 wgt K 2 S0 4 and 25 wgt

K

2

B

4 07-4H 2 0 per liter of deionized water.

V, Use temperature 190 0

F.

c) to an aqueous solution prepared as in a) was added 5 g/l of sodium stearate.

Use temperature 1900 F.

d) to an aqueous solution prepared as in b) was added 5 g/l of ammonium stearate.

Use temperature 1900 F.

The sections of stainless steel panel coated with the above compositions were then tested for hygroscopicity and morphology.

The test results are set forth in Table I below. In Table I, RH relative humidity.

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I TABLE I Hygroscopicity:* Coating Bath 90-95% RH/ Ambient Air Composition 90 min. /24 hr. Morphology a) 16.5% 107.0% Crystalline b) 5.1% 2.7% Amorphous glaze c) 16.1% Crystalline/some glaze d) 7.5% 3.4% Crystalline/some glaze Average percent moisture in the coating. Moisture pick-up measured by weight differential of the uncoated panel and the S. coated panel before and after air exposure.

As can be seen from Table I, the composition of the invention, composition produced a coating with good crystallinity, I and low hygroscopicity.

i EXAMPLE 2 This example shows the effect of relative ratios of sodium i and potassium ions on the hygroscopicity of the water soluble salt coatings. In this example, stainless steel panels were coated in accordance with Example 1 using the following compositions, at a 0 4; concentration of 187.2 g/l in deionized water, set forth in Table 15 II below together with test results. In Table II, M molarity or o «gm-moles/liter of solution and RH relative humidity.

0t Sc 0

C,

20 TABLE II Coating Bath Composition: Hygroscopicity: Na,M K,M S0 4 ,M B 4 0 7 ,M Stearate, M 90-95% RH/24 hrs.

e) 2.23 0.99 0.123 107.0% f) 1.98 0.246 0.99 0.123 90.2% g) 0.246 1.98 0.99 0.123 10.6% h) 2.23 0.99 0.123 2.7% 2.23 0.99 0.123 0.016 3.4% EXAMPLE 3 This example shows the relative hygroscopicity of lime coatings compared to the coating from a known sodium based salt composition and a low sodium salt composition of the invention.

The coatings were produced on samples of the stainless steel wire used in Example 1 according to the procedure of Example 1 from the following aqueous compositions: j) 187.2 g of a mixture of 75 wgt Na 2

SO

4 and 25 wgt sodium tetraborate10H 2 0 per liter of deionized water.

Use temperature 190° F.

1000.

K

V

k) 187.2 g of a mixture of 79 wgt K 2

SO

4 20 wgt sodium tetra- 2 0, and 1 mole of arrmonlum stearate per liter of deionized water.

Use temperature 1900 F.

1) 3% by weight of lime in deionized water.

Use temperature 1900 F.

m) 6% by weight of lime in deionized water.

Use temperature 1900 F.

The results are shown in Table III below.

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:j TABLE III Coating Bath Composition moisture pick-up, 80-90% RH, 24 hrs.

j) 28.3% 15 k) 1) 17.6% m) 18.4% As can be seen from Table III above, composition k) in 20 accordance with the invention has significantly reduced hygroscopicity compared to lime coatings 1) and m).

EXAMPLE 4 Ten different coating bath compositions were evaluated for moisture pick up, morphology, coating uniformity, and crystals per inch on stainless steel panels.

The stainless steel panels were coated with the coating compositions and coating baths set forth 'in Table IV, according to the process given in Example 1, except that the wet-coated panels were dried using a 10 minute bake at 250 0 F. Moisture pick-up was determined in a chamber which allowed constant temperature and humidity of 80 0 F and 92% respectively. A Surtronic 3 surface prophylometer was used to determine the number of crystals per inch of coating. Coating characterization and coating appearance were determined by visual observation.

-7- T 0 a L I o0 o o T A B L E I V o 0 a a o 9 0 Moisture Coating Bath Composition Pick-Up Crystals Coating Bath Tetra g/l 120 Min. Per Coating Coating Ingredients Sodium Potassium ISulfate Borate Stearate RM 92% 0 80 F Inch Characterization Appearance A- Sodium Sulfate B- Sodium Sulfate and Sodium Tetraborate C- Sodium Sulfate and Sodium Stearate Soap (10.0 g/1) D- Potassiua Sulfate It- E- Potassium Sulfate and Sodium Stearate Soap (10.0 g/1) F- Potassium Sulfate and Sodium Stearate Soap (0.1 g/1) G- Potassium Sulfato and Ammoniua Stearate Soap (0.1 g/1) H- Potassium Sulbate and Potassium Tetraborate I- Potassium Sulfate and Sodium Tetraborate J- Potassium Sulfate, Sodium Tetraborate and Sodium Stearate 54.3 51.9 113.2 96.3 113.2 19.3 55.0 0.7 trace 5.7 5.7 75.2 75.2 75.2 75.2 72.3 63.9 63.9 92.3 92.3 92.3 92.3 78.6 78.6 78.6 9.3 9.3 0.09 0.09 0.09 120% 98% 103% 0% 1% 1% 1% 4% 7% 5% 87 126 167 43 50 80 77 93 86 153 Mixed Glaze/Crystalline Crystalline Crystalline Mixed, Mostly Glaze Mixed, Mostly Glaze Mixed Glaze/Crystalline Mixed Glaze/Crystalline Mixed Glaze/Crystalline Mixed Glaze/Crystalline Crystalline Non-Uniform Uniform Mon-Uniform Mon-Uniform Non-Uniform Uniform Uniform Mon-Uniform Non-Uniform Uniform i' In Table IV, coating compositions F, G, and J are compositions in accordance with the invention, while compositions A, SB, C, D, E, H and I are comparison compositions. As can be seen from Table IV, compositions F, G and J produced uniform coatings while exhibiting low moisture pick up. The only comparison com- I position that produced a uniform coating was composition B, which ii however exhibited an unacceptably high moisture pick up. In fact, compositions A, B, and C all exhibited unacceptably high moisture pick up, and hence poor wire drawabillty properties in humid conditions. Coating composition E contains potassium sulfate and Ssodium stearate soap In accordance with the compositions of the j' invention, except that the sodium stearate soap is present in too high a quantity, resulting in a non-uniform, mostly glaze coating, 1i i having unacceptable wire drawing properties. Coating compositions 15 D, H, and I which are potassium salt compositions in accordance with the invention except that no soap is present therein, all produced unacceptable non-ujniform coatings and hence unacceptability inconsistent wire drawing characteristics. In comparing coating compositions F, G and J of the invention, composition J containing an alkali metal tetraborate produced the most crystalline coating. Hence, the presence of a tetraborate in the coating compositions of the invention, while optional, is _nonetheless highly preferred.

Claims

1. A composition for coating steel wire to facilitate the cold drawing thereof, said composition comprising: from 50 to 99.9% by weight of a component selected from the group consisting of Na 2 SO 4 K2S0 4 and mixtures thereof; from about 0 to 49.9% by weight of a component selected from the group consisting of Na 2 B 4 0 7 NaBO 2 K 2 B 4 0 7 KBO 2 and mixtures of any two or more thereof; and from 0.01 to 5% by weight of a component selected from the group consisting of potassium soaps, sodium soaps, and ammonium soaps; wherein the percentages by weight are based on the total weight of components A, B, and C in the composition, and wherein not more than 50% by weight of the total of sodium plus potassium plus ammonium ions in components A, B, and C of the composition consists of sodium ions.

2. The composition of claim 1, comprising ammonium stearate or potassium t earate.

3. The composition of claim 1 wherein not more than 10% by weight of the total of sodium plus potassium plus ammonium ions in the composition consists of sodium ions.

4. The composition of claim 1 wherein there are substantially no sodium ions.

A method for the drawing of steel wire, including the improvement comprising coating the wire prior to drawing with a composition comprising: i from 50 to 99.9% by weight of a component selected from the group consisting of K2SO4, Na 2 SO 4 and mixtures thereof; i from 0 to 49.99% by weight of a component selected from the group |i1 consisting of Na 2 B 4 O 7 NaBO 2 K 2 B 4 0 7 KB0 2 and mixtures of any two or I more thereof; and from 0.01 to 5% by weight of a component selected from the group consisting of ammonium soaps, potassium soaps, sodium soaps and mixtures of any two or more thereof; wherein the percentages by weight are based on the total weight of components A, B, and C in said composition, and wherein not more than 50% by weight of the total of sodium plus potassium plus ammonium ions in the composition consists of sodium ions.

6. A method according to claim 5 wherein component A is present in from 70 to 89.9% by weight, component B is present in from 10 to 29.9% by weight, and component C is -,-Tpresent in from 0.1 to 1.0% by weight.

7. A method according to claim 6, wherein component C is selected from the group consisting of ammonium stearate, potassium stearate, and sodium stearate.

8. The method of claim 5 wherein the steel wire is stainless steel.

9. The method of claim 6 wherein the steel wire is stainless steel.

A method according to claim 5. wherein component C is selected from the group consisting of ammoniurn stearate, potassium stearate, and sodium stearate.

11. A method according to claim 5 wherein not more than 10% by weight of the total of sodium plus potassium plus plus ammonium ions in the composition consists of sodium ions.

12. A method according to claim 11 wherein substantially none of the ions in the S composition are sodium ions.

13. A method according to claim 5 wherein component A is present in from 70 to 89.9% o by weight. 9991

14. A method according to claim 5 wherein componet B is present in from 10 to 29.9% by weight.

A method according to claim 18 wherein component C is present in from 0.1 to in weight. o*

16. A method according to claim 5 wherein component B is selected from K 2 B 4 0 7 and Na 2 B 4 07.

17. A method according to claim 5 wherein the composition includes water which dissolves components A, B, and C to form an aqueous soiution.

18. A method according to claim 17, wherein the composition contains from 70 to 400 grams of the total of components A, B, and C per liter of solution.

19. A method according to claim 18 wherein the aqueous solution contains from 150 to i 250 grams of the total of components A, B, and C per liter of solution.

A method according to claim 11 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from 70 to 400 grams of the total of components A, B, and C per liter of solution.

21. A method according to claim 12 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from 70 to 400 grams of the total of components A, B, and C per liter of solution.

22. A method according to claim 6 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from 70 to 400 grams of the total of components A, B, and C per liter of solution. (fe e

23. A method according to claim 7 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from 70 to 400 grams of the total of components A, B, and C per liter of solution.

24. A method according to claim 9 wherein the composition includes water which dissolves components A, B, and c to form an aqueous solution which contains from 70 to 400 grams of the total components A, B, and C per liter of solution. DATED this 6 day of January 1992 HENKEL CORPORATION i i WATERMARK PATENT TRADEMARK ATTORNEYS LEVEL 4, AMORY GARDENS 2 CAVILL AVENUE ASHFIELD NSW 2131 tj I