Aqueous quenching media and use thereof in quenching metal substrates

1. A quenching concentrate for heat-treating metal substrates, said concentrate comprising;

(a) about 5 to about 20% by weight of a composition comprising:

(i) a non-ionic, water-soluble or water-dispersible polyvinylpyrrolidone/polyvinylcaprolactam copolymer; and

(ii) a non-ionic, water-soluble or water-dispersible polymer comprising a poly(oxyethyleneoxyalkylene) glycol polymer; and

(b) about 80 to about 95% by weight water.

2. The concentrate according to claim 1 , wherein component (i) is of formula I:

wherein:

R is a caprolactam;

n and m are, independently, integers, provided that said polymer of component (i) has a molecular weight of about 5,000 to about 2,000,000 and a K-value of about 60 to about 70.

3. The concentrate according to claim 2 , said copolymer (i) comprising about 75% of n and about 25% of m.

4. The concentrate according to claim 1 , wherein said polyvinylpyrrolidone/polyvinylcaprolactam copolymer (i) has a molecular weight of about 50,000 to about 1,000,000.

5. The concentrate according to claim 1 , wherein component (ii) is of formula III:

wherein:

R 2 is a chemical moiety that maintains the water solubility of said polymer (b);

x and y are integers, provided that said polymer (b) is water-soluble and said polyoxyethylene/polyoxyalkylene polymer has a molecular weight of about 1,000 to about 500,000.

6. The concentrate according to claim 5 , wherein R 2 is an alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, or substituted alkynyl.

7. The concentrate according to claim 1 , further comprising one or more of a bacteriocidal agent, preservative, corrosion inhibitor, buffer, metal deactivator, and defoamer.

8. The concentrate according to claim 1 , wherein the ratio of component (i) to component (ii) is about 90:10 to about 10:90.

9. The concentrate according to claim 1 , comprising:

(i) a vinylpyrrolidone/vinylcaprolactam copolymer having a molecular weight of about 50,000 to about 1,000,000; and

(ii) a polyoxyethylene/polyoxyalkylene copolymer having a molecular weight of about 1,000 to about 500,000.

10. The concentrate according to claim 1 comprising:

(i) a vinylpyrrolidone/vinylcaprolactam copolymer having a molecular weight of about 100,000 to about 200,000; and

(ii) a polyoxyethylene/polyoxyalkylene copolymer having a molecular weight of about 5,000 to about 100,000.

11. A concentrate for preparing an aqueous quenching medium useful in the heat treatment of metal substrates, said concentrate comprising:

(a) about 5% to about 20% by weight of a mixture of:

(i) a nonionic, water-soluble or water-dispersible substituted vinylpyrrolidone/vinylcaprolactam polymer of formula I:

wherein:

R is a caprolactam;

n and m are independently integers, provided that said polymer of component (i) has a molecular weight of from about 5,000 to about 1,000,000 and a K-value of about 60 to about 70; and

wherein said vinylpyrrolidone/vinylcaprolactam copolymer has a vinylpyrrolidone component of about 10 to about 90 mol%, said copolymer has a vinylcaprolactam component of about 90 to about 10 mol%, and the sum of said vinylpyrrolidone and vinylcaprolactam components is 100 mol%; and

(ii) a polyoxyethylene/polyoxyalkylene polymer having formula III:

wherein:

R 2 is an alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, or substituted alkynyl;

x and y are integers, provided that said polymer (b) is water-soluble and said polyoxyethylene/polyoxyalkylene polymer has a molecular weight of about 1,000 to about 500,000; and

(b) about 80 to about 95% by weight water.

12. The concentrate according to claim 11 , wherein said vinylpyrrolidone/vinylcaprolactam copolymer has a molecular weight of about 50,000 to about 1,000,000.

13. A method for quenching a heated metal substrate, said method comprising:

I. mixing the concentrate of claim 1 with a carrier, water, or a combination thereof; and

II. quenching said heated metal substrate with the product of step I.