USE OF AMINE BLENDS FOR FOUNDRY SHAPED CORES AND CASTING METALS

Abstract

Provided is a catalyst suitable for curing a composite resin composition that includes comprising a blend of at least two tertiary amines selected from dimethylethylamine (DMEA), diethylmethylamine (DEMA), dimethylisopropylamine (DMIPA), and dimethyl-n-propylamine (DMPA), where each of the at least two tertiary amines is present in the blend in an amount of not less than 10% by weight and not more than 90% by weight.

Claims

1-17. (canceled)

18. A catalyst suitable for curing a composite resin composition, comprising a blend of at least two tertiary amines selected from the group consisting of dimethylethylamine (DMEA), diethylmethylamine (DEMA), dimethylisopropylamine (DMIPA), and, dimethyl-n-propylamine (DMPA), wherein each of the at least two tertiary amines is present in the blend n an amount of not less than 10% by weight and, not more than 90% by weight.

19. The catalyst of claim 18, which comprises dimethylethylamine (DMEA).

20. The catalyst of claim 8, which comprises diethylmethylamine (DEMA).

21. The catalyst of claim 18, dl ich comprises dimethylethylamine (DMEA) and diethylmethylamine (DEMA).

22. The catalyst of claim 18, which dimethylethylamine (DMEA) and dimethylisopropylamine (DMIPA).

23. The catalyst of claim 18, which comprises dimethylethylamine (DMEA) and dimethyl-n-propylamine (DMPA).

24. The catalyst of claim 18, which further comprises at least one additional tertiary amine having 6 to 10 carbons.

25. The catalyst of claim 18, wherein the blend of at least two amines is chosen from 50/50 DMEA/DMIPA, 20/80 DMEA/DMIPA, 10/90 DMEA/DMIPA, 50/50 DMA/DMPA, 20/80 DMEA/DMPA, 10/90 DMEA/DMPA, 50/50 DMEA/DEMA, 20/80 DMEA/DEMA, or 10/90 DMEA/DEMA by weight.

26. The catalyst of claim 18, wherein the catalyst comprises 10% to 50% by weight of DMEA.

27. The catalyst of claim 18, wherein the catalyst consists of DMEA and DEMA.

28. The catalyst of claim 18, wherein the DMEA is present in an amount ranging from 10% to 50% by weight of the catalyst.

29. (canceled)

30. A composition, comprising the catalyst of claim 18, a binder, and an aggregate.

31. A process of preparing the catalyst of claim 18, comprising combining the at least two tertiary amines.

32. A process for preparing a foundry shape by a cold box process, comprising: (a) forming a foundry mix comprising a binder and an aggregate, (b) forming a foundry shape by introducing the foundry mix obtained from (a) into a pattern, (c) contacting the foundry shape with the catalyst of claim 18, in a liquid or a gaseous form, optionally with an inert carrier, (d) hardening the foundry shape into a hard, solid, cured shape, and (e) removing the hardened foundry shape of (d) from the pattern.

33. The process of claim 32, wherein the inert carrier is gaseous and chosen from nitrogen, air, carbon dioxide or mixtures thereof.

34. The process of claim 32, wherein the catalyst further comprises up to 25% by weight of at least one primary and/or secondary amine.

35. The process of claim 32, wherein the catalyst further comprises 0.2% by weight of water.

36. The process of claim 32, wherein the catalyst further comprises at least one additional tertiary amine having 6 to 10 carbons.

37. The process of claim 32, wherein the catalyst is chosen from DMEA-DMIPA, DMEA-DEMA, or DMEA-DTPA.

38. The process of claim 32, wherein the catalyst is chosen from 50/50 DMEA/DMIPA, 20/80 DMEA/DMIPA, 10/90 DMEA/DM1PA, 50/50 DMEA/DMPA, 20/80 DMEA/DMPA, 10/90 DMEA/DMPA 50/50 DMEA/DMA, 20/80 DMEA/DMA, or 10/90 DMEA/DEMA, by weight.

39. The process of claim 32, further comprising the step of hardening the hardened foundry shape obtained from (e).

40. The process of claim 32, further comprising; (f) pouring metal in the liquid state around said hardened foundry shape; (g) allowing the metal to cool and solidify forming a mounded article; and (h) separating the molded article and the hardened foundry shape.

41. The process of claim 32, wherein the catalyst further comprises up to 10% by weight of at least one primary and/or secondary amine.

42. The process of claim 32, wherein the catalyst further comprises up to 0.5% by weight of at least one primary and/or secondary amine.

43. In a process for preparing a hardened foundry shape by a cold box process, the improvement comprising contacting a foundry shape containing a foundry mix comprising a binder and an aggregate with the catalyst according tea claim 18.

44. A catalyst suitable for curing a composite resin composition, comprising a blend of at least two tertiary amines selected from the group consisting of 50/50 dimethylethylamine (DMEA)/diethylmethylamine (DEMA), 20/80 DMEA/DEMA, and 10/90 DMEA/DEMA, by weight.

45. The catalyst of claim 44, wherein the blend of at least two tertiary amines is 50/50 DMEA/DMEA, by weight.

46. The catalyst of claim 44, wherein the blend of at least two tertiary amines is 20/80 DMEA/DMA, by weight.

47. The catalyst of claim 44, herein the blend of at least two tertiary amine is 10/90 DMEA/DMA, by weight.

48. A composition, comprising the catalyst of claim 44, a binder, and an aggregate.

49. A process of preparing the catalyst of claim 44, comprising combining the DMEA and DEMA.

50. A process for preparing a foundry shape by a cold box process, comprising: (a) forming a foundry mix comprising a binder and an aggregate, (b) forming a foundry shape by introducing the foundry mix obtained from (a) pattern, (c) contacting the foundry shape with the catalyst of claim 44, in a liquid or a gaseous form, optionally with an inert carrier, (d) hardening the foundry shape into a hard, solid, cured shape, and (e) removing the hardened foundry shape of (d) from the pattern.

Description

EXAMPLES

[0107] A test was firstly carried out for the measurement of the optimized, i.e. minimum amount of, amine quantity of a single tertiary amine (DMEA, DEMA or DMIPA) or a blend of tertiary amines (DMEA-DEMA, DMEA-TEA) for full curing in order to show the difference of reactivity.

[0108] The various resins used for this test are commercial resins from Ashland-Avebene (Usine du Goulet-20, rue Croix du Vallot, 27600 St Pierre-la-Garenne, France) sold under the trade name Avecure; these resins are composed of a formo-phenolic resin and of an isocyanate resin, in accordance with the present description.

[0109] The catalytic behaviour of the tertiary amines in polyurethane curing is assessed for each any resin: full curing of a 1.870-1.880 kg cylinder (length 300 mm.times.diameter 70 mm) of sand LA32+binder requires about 0.2-0.4 mL of DMEA, while it requires up to almost 1 mL of DEMA and can require up to about 1.5 mL of TEA. While using blends of DMEA-DEMA or DMEA-TEA, the following results are obtained:

Example 1

[0110] Blends of DMEA/DEMA

[0111] A fixed amount of sand+resins mixture with a predetermined amount of resins per mass unit of sand (normally between 0.5 and 2% by weight of each resin based on the amount of sand mixed) is placed in a long cylindrical shaped mould, the amine is poured as liquid ahead of the sand-resins cylinder in a U tube and a heated stream of carrier gas (normally nitrogen) at a fixed and predetermined rate is passed through the amine loaded U tubing.

[0112] The carrier gas stream brings the volatilized amine to the cylinder filled with sand+binder during a fixed time. Test cores were prepared as follows:

[0113] Into a laboratory mixer, 0.8 part by weight of the phenolic resin solution and 0.8 part by weight of the polyisocyanate solution are added to 100 parts by weight of sand LA32 (Silfraco), in the order given, and mixed intensively for 3 minutes. 6 kg of fresh sand are used for each resin to be cured. This quantity allows 3 gassings of 1.870-1.880 kg of sand+binder for repeatability sake.

[0114] The 3 gassings are made at 5.5 bars (static) equivalent to 4.8 bars (dynamic). 2 purgings of 10 seconds each are applied between each gassing operation. Gassing itself lasts 10 seconds at 1.5 bars (dynamic). Carrier gas heater is adjusted to 75.degree. C.+0.3.degree. C. except for TEA for which it was modified to 95.degree. C.

[0115] The optimum (lowest) volume for 100% curing for each amine or blend of amine is obtained by increasing the volume of injected amine(s) by steps of 0.05 mL from 0, until reaching the catalytic volume for which no more sand is left free (100% curing, the sand+binder test core is totally solidified).

[0116] Amine(s) optimized volumes have been converted to weights required for full curing through usage of their corresponding densities. The amines density was measured or checked from literature on a densimeter Metier Toledo DA-100M. The density of DMEA is 0.678, the one of DEMA is 0.706, density of TEA is 0.728.

[0117] The checking of density value of blends versus the predicted one based on linear combination of individual density of each amine of the composition have shown that no volume contraction intervenes that could have accounted for lower volumes than expected at application.

[0118] Table 1 indicates the amounts (in grams) of single tertiary amine (DMEA or DEMA) and the amount of different DMEA/DEMA blends required for a full curing core test as described above. Theoretical masses (Theo. Mass) of blends needed for 100% test core curing in Table 1 are calculated according to the following equation:

[0119] Theo Mass=(ratio of DMEA.times.mass of DMEA alone needed for full curing+ratio of DEMA.times.mass of DEMA alone needed for full curing).

[0120] TABLE-US-00001 TABLE 1 Type of Resin Avecure Avecure Avecure Amine 333/633 331/631 363/663 Mass of DMEA required 0.3051 0.339 0.2034 for 100% curing Mass of DEMA required 0.5656 0.777 0.31815 for 100% curing Experimental Mass of 50/50 0.38115 0.4158 0.2079 DMEA/DEMA blend Theoretical Mass of 50/50 0.43535 0.55835 0.260775 DMEA/DEMA blend Experimental Mass of 20/80 0.3861 0.5967 0.2808 DMEA/DEMA blend Theoretical Mass of 20/80 0.5135 0.68996 0.2952 DMEA/DEMA blend Experimental Mass of 10/90 0.45825 0.6345 0.282 DMEA/DEMA blend Theoretical Mass of 10/90 0.53955 0.73383 0.306675 DMEA/DEMA blend

[0121] From the results of Table 1, it can be easily seen that a blend of DMEA-DEMA containing 10, 20 or 50% of DMEA is more reactive than DEMA alone, as seen by lower quantities requested for full curing in the case of blends.

[0122] The results given in Table 1 also indicate that for 10/90, 20/80 and 50/50 blends of DMEA/DEMA, the required global amount of amines for full curing the test core is lower that the scheduled one based on single amines, i.e. (ratio of DMEA.times.mass (g) of DMEA alone needed for full curing+ratio of DEMA.times.mass (g) of DEMA alone needed for full curing).

Example 2

[0123] Blends of DMEA/TEA

[0124] Theoretical masses (Theo. Mass) of blends needed for 100% test core curing are calculated according to the following equation:

[0125] Theo Mass=(ratio of DMEA.times.mass of DMEA alone needed for full curing+ratio of TEA.times.mass of TEA alone needed for full curing).

[0126] Table 2 indicates the amount of single tertiary amine (DMEA or TEA) and the amount of different DMEA/TEA blends required for a full test core curing as described above.

[0127] TABLE-US-00002 TABLE 2 Amine Mass (g) Mass (g) of of TEA Experimental Theoretical DMEA required mass (g) of mass (g) of required for for 100% 20/80 DMEA/20/80 DMEA/Resin 100% curing curing TEA blend TEA blend Avecure 0.3729 0.9464 0.612 0.8317 373/673 Avecure 0.3051 1.456 0.936 1.22582 353/653 Avecure 0.3051 1.456 0.792 1.22582 333/633 Avecure 0.339 1.456 0.936 1.2326 331/631 Avecure 0.2034 0.9464 0.36 0.7978 363/663

[0128] The results of Table 2 show that quantities of the 20/80 DMEA/TEA blend needed for a full curing of the test core are lower than the quantity of TEA alone needed for a 100% curing.

[0129] The results of Table 2 also show that quantities of the 20/80 DMEA/TEA blend needed for a full curing of the test core are lower than theoretical amounts of the 20/80 DMEA/TEA blend as calculated by adding proportionally the optimized quantities of individual amines when used alone.