CA2009377A1

CA2009377A1 - Water soluble salt precoats for wire drawing

Info

Publication number: CA2009377A1
Application number: CA002009377A
Authority: CA
Inventors: Thomas W. Tull
Original assignee: Individual
Current assignee: Henkel Corp
Priority date: 1989-02-07
Filing date: 1990-02-06
Publication date: 1990-08-07
Also published as: AU4920990A; ES2059847T3; AU621980B2; EP0382155B1; ZA90917B; BR9000543A; DE69002649D1; JPH02229893A; DE69002649T2; CN1044774A; DK0382155T3; EP0382155A1; ATE92951T1

Abstract

ABSTRACT OF THE DISCLOSURE
Compositions for coating steel wire to faciliate the cold drawing thereof comprising: A. from about 50 to about 99.9% by weight of K2SO4; B. from about 0 to about 49.99% by weight of K2B4O7 and/or KBO2; and C. from about 0.01 to about 5% by weight of an ammonium and/or a potassium soap; wherein up to 50% by weight of the total potassium plus ammonium ions in the composition can be replaced by sodium ions. These compositions form coatings which have good crystalline structure and drawability with low hydroscopicity.

Description

20~3~7 WArER SOLUBLE SALT PRECOATS FOR ~IRE DRA~ING

BACK~ROUND OF THE I~VENTION
.

I. Field of the InYentlon Thls inventlon relates to modifled water so1uble salt precoats for use ~n the cold drawlng of steel w~re.

2. Backg ound o~ the InYentlon 5~ater soluble salt codt~ngs are often applied to steel w~re 1n the for~ of a~ueous solutions pr10r to drawlng. The solution-coated wire ls dried and the result1ng salt coated wlre 1s then drawn through conventlonal reduc~ng dles uslng dry soap lubricants - a process well-known to this art. The water soluble IOsalt coating acts as a lubrlcant carrler, pulllng the dry soap box lubricant ~nto the dles, thus provldlng lubrlcat10n. These drled-in-place, water soluble salt coatings have proven to be superior to other convent10nal coatings such as llme or borax coatings because of their lmproved abillty to carry lubrlcank lnto the 15dles, A typlcal soluble salt composlt~on used for the coatlng of steel (usually stalnless steel) wire conta~ns both sodlurn sulfate and borax. Such soluble salt composltions prov~de coattngs wlth excellent crystall~ne structure, resultln~ ln good soap lubr~cant plck up when the coated wlre ls passed through a soap box, and ~0therefore good drawablllty. ~owever, such salt coatlngs are prone 2~ 377 to excesslve molsture absorptlon upon exposure to amblent alr, partlcularly when exposed to alr haY1ng hlgh humldlty. Such mols~ure absorptlon serlously lnterferes wlth, or even prevents, the draw~ng of the coated wlre. 5n the other hand, soluble salt coatlngs whlch prov~de low rnolsture absorptlon orovlde 11ttle or oo crystalllne structure (~.e. amorphous or glaze type coatings) and arP slgnlflcantly infer~or ln both lubrlcant plck-up and drawa blllty. Thls Hobson's cholce problem has not prevlously been solved.
STA~EMENi OF TI~E INYENTION
Other than ln the operatlng examples, or where otherw~se lndicated, all numbers expresslng quantlt~es of lngre~ents or reactlon conditions used herein are to be understood as modif~ed 1n all lnstances by the ter~ "aboutn.
Compositions for coat~ng steel wire have now been dlscovered which prov~de uniform coatings wlth good crystalllne structure, soap pick-up, and drawability, while at the same time low moisture absorptlon even dur~ng humid days, t.e. low hygroscoplclty.
The compositions of the lnvent~on, which are in the for~ of dry m~xtures prior to d11utlon with water for use, conta~n the ~ollow~ng components:
A. from 50 to 99.99, preferably from 70 to 89.9% by we~ght K2SO4;
B. from O to 49099, preferably from 10 to 29.9~ by welght K2B407 and/or KB02; and C. fro~ 0.01 to 5, preferably from 0.1 to 1.0% by we~ght of an ammonium or potasslum soap, wherein up to 50% by welght, and preferably no more than 10X
by we~ght, of the total potasslum lons and arnmon~um lons pre-sent ln A., B. and C, can be replaced wlth sodlum lons. More preferably, substantlally none o~ the potasslum and ammon~um are replaced wlth sodlum lons, slllce the more sod1um ~ons present, the greater the hygroscoplclty. When sodlum 10ns are present, they can be present ln one or more o~ components A~, 2 ~ 7 B. and C., e.g. component C. can be part~ally or entlrely a sodlum soap. Al 50, component A. andlor B. can be a sodlum or a potasslum salt, or a ml~ture of such salts, provlded the llmitat10n on total quantlty of sod~ùm lon ~5 rr~lntalned.
S The fdct that the above compos~tlons prov~de Qood crystalll -nity on steel wlre ls completely unexpe~ted, s1nce the above cotnpos~t~cns without component C. glve non-unlform csat1ngs on steel wlre wh~ch are not useful as such s~nce both soap p1ck-up and drawabll~ty are unsatisfactory. In some unknown manner, the I0 presence of t~le soap prov1des an at least part1ally crystalllne uniform coatinq when the composition ln aqueous solut~on 1s applled to the steel w1re wh1ch is then dried or allowed to dry.
The K2SO~ used as c~mponent A. can be chemlcally pure or of a technlcal grade; the latter be1ng preferred due to cost con~
sider~tions.
The K2B407 used as component B. can also be chemically pure or a techn~cal grade, and 1s generally available and used here1n as the tetrahydrate (K2B407-4H20). Slmilarly, the KB02, whlch can be used alone as component B, or ~n a mlxture wlth K2B407 1n any proport10ns, can be chemlcally pure or a techn~cal grade.
The am~on1um or potass1um soap ~s one or more ammon~um andlor potass1um salts of a C12-C22 fatty ~c~d or m~xture of two or more such C12-C2~ fatty ac1ds. The fatty ac1ds are general1y saturated and unbranched, wlth ammon1um or potass1um stearate belng pre-ferred for use here1nl although mono- or dl-olefln~cally unsa-turated C12-C22 fatty ac1ds can also be employed, e~ther alone or 1n m1xtures wlth each other andlor wlth saturated fatty acldsO For example, amrnon~um and potass~um soaps der1ved frcm the fatty acld mlxtures obtalned by the saponificatlon of tallow oil or coconut oil, or a mlxture thereof, can advantageously be employed as com-porlent C~ Also, ar~non1um or potass~um salts of branched or cycloal~phatlc-conta~nlng Cl2-C22 fatty aclds can also be employed here1n, elthcr alone or ln m~xtures wlth unbranched fatty acld salts. A~so, am~onlum or potass~m ros~n ac1ds, e.g. ab1etlc acld, can also be employed as c~nponent C~
The w1res coated w~th the coatlng composltlons o~ the lnven-t~on are generally steel wlres, and usually stalnless steel w1res.

2~37~

However, other w1re substrates can also be coate~ wlth the present coatlng composltlons such as mlld steel, t1tanlum, vanadlum, tungsten, alumlnum, copper, nlckel, zlrconlum, etc., and alloys thereof.
S The cGatlnys are dpplled by contactlng the w1res wlth an aqueous solutlon o~ the c~nposltlon of the Invent10n, and allowlng the resulting wet coatlng to dry ln place, elther wlth or w1thout the apptication of heat. ~he aqueous solutlons generally conta1n from 75 to 400 g/l of the c~mpos1t~on in water, preferably from l50 to 250 ~Jl.
The wlre ls contacted with the solut~on by any conYenlent technique, elther batch or a continuous strand, and allowlng the resultlng wet-coated w1re to air dry before coll~ng ~or storage, shlpping, or use. The coated wlre ls then passed through conven-t~onal cold reduction equipment using a soap box (e.g. contain~ng a conventlonal dry soap lubrlcant). The coat1ng on the w~re functlons as a carrier to carry the dry soap lubrlcant lnto the d~e.
The steps employed in the treatment of wlre accord~ng to the invention lnclude the follow~ng:
1. Cleanlng the w~re - cleaning composltlons are well~known ln the art and dc not comprlse part of the present Invention.
2. Rlnslng wlth water.

3. Pickllng - here atso, pickllng composltlons are well-known and the selectlon of a plckllng composltlon Ic not part of the lnventlon.

4. Rlnslng wlth water.

5. Applying the coatlng composit10n of the 1nventlon as descrlbed above.

6. Drylng the wlre as descr~bed above to produce the coated wlre o~ the 1nventlon.
The coated wlre can then be drawn, also as descrlbed above, The water used ln preparlng the aqueou5 solutlons o~ the lnventlon lS pre~erably dlstllled or delonlzed water, but tap water can also be used provlded lt ls not overly hard and has a low dlssolved sodlum salts contentu , -4-` 2~3~

The lnventlon wlll be lllustrated but not llmlted by the follow~ng examp1es.
EXA~PLES

The follow1ng 3queous cornposltlons were tested ~or the~r morphology and hygroscopic~ty, when coated on stalnless steel panels. Stalnless steel panels were coated wlth each of the follow~ng composltions by ~rmerslng the panels ln the aqueous com-posltion, removlng the ,oanels ,rom the ~ueous c~mposlt~on, and allow~ng them to fldsh (alr) dry.
a) 187.2 Q of a mixture of 75 wgt X Na2S04 and 25 wgt X
sodlum tetraborate 10H20 per liter o~ delonlzed water.
Use temperature l90F.
b) 187.2 g of a m~xture of 75 wgt % K2S04 and 25 wgt X
~2B~07 4HzO per llter of deionized water.
Use temperature 190F.
c) to an aqueous solut~on prepared as ln a) was added 5 gll of s~dlum stearate.
Use temperature l90 F~
d) to an aqueous solution prepared as ln b) was added 5 9/1 of a~mon1um stearate.
Use t~mperature 190 F.
The sectlons of sta~nless steel panel coated w1th the above compositlons were then tested for hygroscopiclty and morphology.
The test results are set forth ln Table I be10w. In Table I, RH
relatlve hum~d~ty.
TABLE I
e}9C'~55EL~.LC~
Coat1ng Bath ~0-95X RH/Amblent Alr ~tlon 90 mln. _24 hr. MorPh a) 16.5X 107.0X Crystalllne b) 5,1X 2.7X Amorphous glaze c) lG. }% - Crystal 1 lnelsome glaze d) 7.5X_ _ _ 3 4X _ _ _Cr,xstalllne/some~_ze 2~Q~3~7 * Average percent molsture ln t~,e coatlng. Molsture p1ck-up measure~ by welght d~fferentlal o~ the uncoated panel and the coated panel before and after alr exposure.
As can be seen from Table I, the compositlon of the lnven-tlon, composlt~on d), produced a coatlng wlth good crystall~n~ty, and low hygroscoplcity.

Thls example shows the effect of reldtlve ratlos of sodium and potassium ions on the hygrosc3picity of the water soluble salt coat~ngs. In th1s exarnple, stalnless steel panels were coated ln accordance with Example 1 using the follow1ng compositlons, at a concentratlon of 187.2 g/l ln delonlzed water, set forth ln Table ~I be~ow together w~th test results. In Table Il, M = molarlty or gm-moles/liter of solution and RH = relatlve humidlty.
TABLE II
.
Coatlng Bath Composltlon: Hygroscoplclty:
Na,M K,M S04,~B407,MStearate, M90-95X RH/24 hrs.
e) 2.23 - 0.99 0.123 - 107.0X
f) 1.98 0.246 0.99 0.123 - 90.2%
9~ 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 3.4X
. _ _ _ _ . _ _ _ _ _ . . ~ _ _ _ . _ _ _ _ _ .

Thls example shows the relatlve hygroscop~c1ty of l~me coatlngs compared to the coatlng from a known sodlum basecl salt composltlon and a low sodlum salt composltlon of the lnventlon.
rhe coatlngs were produced on samples of the stalnless steel w~re used ln Example 1 accordlng to the procedure of Example 1 trom the follow1ng aqueous composltlons:
~) 187.2 9 of a mixture of 75 wgt X Na2S04 and ?5 wgt ~ sodlum tetraborate~lOH20 per 11ter of delonlzed water.
Use temperature 190 F.

2~Q~37~

k) 1a~.2 9 o~ a mlxture of 79 wgt X K2S04, 20 wgt % sodlum tetr~-borate lOH20, and 1 mole X or ammonlum stearate per llter o~
delonlzed water.
Use te~perature 1gO F.
l) 3% by welght of lllne ln de~on1zea water.
Use temper~ture 190 F.
m) 6% by welght of llme 1n delon~zed water.
Use temperature 190~ F.
The results are shown ln Table III be1Ow.
TA~LE I I I
Coat1ng Bath ~p_slt10n% molsture plck-up, 80-9OX RH, 24 hrs J~ 28.3X
k) 3.0X
1) ~7.6~
_m) - 18.4X
~ . . .
As can be seen from Table III above, c~mposltlon k) ln accordance wlth the lnvent10n has slgnlflcantly reduced hygrosco-plctty compared to l~me coatlngs l) and m).

Ten dlfferent coatlng bath composltlons were evaluated for ~5 molsture plck up, morpholo~y, coatlng un1fonm1ty, and crystals per lnch on stalnless steel panels.
The stalnless steel panels were coated wlth the coatlng com-posltlons and coatlny baths set forth ln Table IY, accordlng to the process glven ln Example 1, except that the wet-coated panels were dr~ed us~ng a I0 mlnute bake at 250F. Molsture plck-up was determlned ln a chamber whlch allowed constant temperature and humldity of 80F and 92X respectlvely. A Surtron~c 3 sur~ace prophylometer was used to determlne the number o~ crystals per lnch o~ coatlng. Coatlng characterlzatlon and coatlng appearance 3S were determlned by vlsual observatlon.
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.

20~377 In ~able IV, coatlng composltlons F, G, dnd J ara com-po51tlon5 ln accordance wlth the lnYentlon, whlle coTposltlons A9 B, C, ~, E, H and I are comparlson composltlons. As can be seen fr~m Table IV, conpos~t~ons F, G and J prodused unl~orm coatlngs whlle exhlbltlng low mo1sture plck up. The only cDmparlson com-posltlon that produced a unlform coat1ng waj c~mposltlon B, whlch however exhl~lted an unacceptably h1gh ~olstur~ plck up. In fact, composltions A, B, and C all exhlbited un3cceptably hlgh molsture plck up, and hence poor wlre drawablllty propertles 1n humld con-ditlons. Coat~ng cornpos1tlon E contalns potasslum sulfate andsodium stearate soap 1n accordance wlth the composltlons of the lnven~lon, except that the sodlum stearate soap 15 present in too hlgh a quantlty, resultlng ln a non-unlform, r~stly glaze coatlng, havlng unacceptable wlre drawlng propertles. Coatlng composltlons D, H, and I whlch are potass1um salt co~posltlons ln accordance with the lnYention except that no soap ls present thereln, all produced unacceptable non-unifùrm coatings and hence unaccep-tability intonslstent w1re drawing characterlstlcs. In comp~rlng coating compositions F, G and J of the lnventlon, c~mposltlon J
contaln1ng an alkall metal tet,aborate produced the most crystalline coatlng. Hence, the presence of a tetraborate ln the coat~ng conposltlons of the lnventlon, ~hlle optlonal, ls nonetheless highly preferred.

Claims

1. A composition for coating steel wire to faciliate 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 Ha2SO4, 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.

2. In a method for the drawing of steel wire, the improvement comprising coating the wire prior to drawing with a composition comprising:
(A) from about 50 to about 99.99% by weight of a component selected from the group consisting of K2SO4, Na2SO4, 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% 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.

3. A method according to claim 2, wherein component A is present in from about 70 to about 89.9% by weight, component B is present in from about 10 to about 29.9% by weight, and component C is present in from about 0.1 to about 1.0% by weight.

4. The method of claim 2 wherein the steel wire is stain-less steel.

5. The method of claim 3 wherein the steel wire is stain-less steel.

6. A method according to claim 2 wherein component C is selected from the group consisting of ammonium stearate, potassium stearate, and sodium stearate.

7. A method according to claim 2 wherein not more than 10%

by weight of the total of sodium plus potassium plus ammonium ions in the composition consists of sodium ions.

8. A method according to claim 7 wherein substantially none of the ions in the composition are sodium ions.

9. A method according to claim 2 wherein component A is present in from about 50 to about 89.9% by weight.

10. A method according to claim 2 wherein component B is present in from about 10 to about 29.9% by weight.

11. A method according to claim 2 wherein component C is present in from about 0.1 to about 1.0% by weight.

12. A method according to claim 2 wherein component B is selected from K2B4O7 and Na2B4O7.

13. A method according to claim 2 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution.

14. A method according to claim 13 wherein the composition contains from about 70 to about 400 grams of the total of components A, B, and C per liter of solution.

15. A method according to claim 14 wherein the aqueous solution contains from about 150 to about 250 grams of the total of components A, B, and C per liter of solution.

16. 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 form about 70 to about 400 grams of the total of components A, B, and C per liter of solution.

17. A method according to claim 8 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from about 70 to about 400 grams of the total of components A, B, and C per liter of solution.

18. A method according to claim 3 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from about 70 to about 400 grams of the total of components A, B, and C per liter of solution.

19. A method according to claim 4 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from about 70 to about 400 grams of the total of components A, B, and C per liter of solution.

20. A method according to claim 5 wherein the composition includes water which dissolves components A, B, and C to form an aqueous solution which contains from about 70 to about 400 grams of the total of components A, B, and C per liter of solution.