Hot test fluid containing vapor phase inhibition

Abstract

This invention covers a formulation providing protection against corrosion in liquid and vapor phase. Such formulations are used in applications where engine parts or fuel cell systems are subjected to a running-in or hot-test prior to final assembly or storage. The invention includes a concentrate as well as a dilute solution. The synergistic combination of inorganic ammonium derivatives in combination with monocarboxylic or dicarboxylic acids increases the period of protection. This enables storage for a longer period when the engine parts are shipped or stored prior to assembling. The use of the described invention pre-conditions the metal surface and provides protection even if afterwards the liquid is almost completely removed.

Claims

1. A glycol free coolant fluid providing anti-corrosion properties in both the liquid and vapor phases during the running-in phase of an engine, said fluid comprising ammonium bicarbonate present in the range from about 0.05 wt % to about 10 wt %, at least one carboxylic acid present in a range of from about 0.2 wt % to about 15 wt %, and water present in a range of from about 50 wt % to 95 wt % and not including a glycol as a freezing point depressant.

2. The fluid of claim 1, wherein the ammonium bicarbonate is present in an amount from about 0.05 wt % to below 5 wt %.

3. The fluid of claim 2, wherein the ammonium bicarbonate is present in the range from 0.05 to 2 wt %.

4. The fluid of claim 1, which further comprises a freezing point depressant that is an organic salt.

5. The fluid of claim 4, wherein the organic salt is selected from the group consisting of formiate, acetate, proprionate, adipate, succinate, and combinations thereof.

6. The fluid of claim 1, wherein the at least one carboxylic acid is selected from the group consisting of monocarboxylic acids, dicarboxylic acids, aliphatic monocarboxylic acids, aliphatic dicarboxylic acids, branched carboxylic acids, aromatic unbranched carboxylic acids, aromatic branched carboxylic acids, and combinations thereof.

7. The fluid of claim 1, wherein the fluid has a pH of 8.8 to 12.0.

8. The fluid of claim 1, wherein the at least one carboxylic acid is isononanoic acid.

9. The fluid of claim 1, wherein the at least one carboxylic acid is a mixture of an aliphatic monocarboxylic acid and an aliphatic dicarboxylic acid.

10. The fluid of claim 1, wherein the at least one carboxylic acid comprises a mixture of isononanoic acid and sebacic acid.

11. The fluid of claim 1, further comprising a coolant additive selected from the group consisting of silicates, nitrates, phosphates, anti-oxidants, thiazole derivatives, triazole, polyacrylates, phosphonates, borates, and mixtures thereof.

12. The fluid of claim 11, wherein the coolant additive is a triazole.

13. The fluid of claim 12, wherein the triazole is tolyltriazole.

14. A process for protecting a metal surface from corrosion comprising pre-conditioning the surface with a glycol free coolant fluid comprising anti corrosion properties in both the liquid and vapor phases, the fluid comprising ammonium bicarbonate present in the range from about 0.05 wt % to about 10 wt %, at least one carboxylate acid which is present in a range of from about 0.2 wt % to about 15 wt %, and water present in a range of from about 50 wt % to 95 wt % and not including a glycol as a freezing point depressant.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The instant invention preferably employs water as solvent, and combines the positive characteristics from both coolants and oil emulsions. It has the excellent compatibility with coolants added subsequently, and does not negatively affect heat transfer characteristics, as would an oil emulsion. It also provides sustainable corrosion protection during the running-in period as well as during subsequent storage, when most of the product has been drained. Best results are observed when the part is sealed or air flow is not completely free. This allows the additives to come to equilibrium and condition the atmosphere so corrosion protection is guaranteed during storage or transport.

(2) One embodiment of the invention may be a concentrate used to prepare a running-in or hot test fluid. It may be diluted as a second embodiment. Alternatively also a freezing protection base fluid like an alcohol or short chain organic acid can be added for those situations where freezing protection would be needed during storage or transport.

(3) The addition of a liquid with increased viscosity relative to water to provide freeze protection further improves the protection level during storage and or transport. As those freezing depressant fluids have a higher viscosity and are considered to be slippery, they are not preferred unless freeze protection is really needed. Freezing point depressant may be present in the range from 10 to 60 vol %, preferably in the range from 30 to 50 vol %. A liquid alcohol or organic salt freezing point depressant component can be added to provide freezing protection. The freezing point depressant can contain polyalcohols such as ethylene glycol, di-ethylene glycol, propylene glycol, di-propylene glycol, and glycerin and glycol monoethers such as the methyl, ethyl, propyl and butyl ethers of ethylene glycol, di-ethylene glycol, propylene glycol and di-propylene glycol. Ethylene and propylene glycol are particularly preferred as the freezing point depressant component. Non-limiting examples of organic acid salt as freezing point depressant include esters of carbrexylic acids, including formiate, acetate, propionate, adipate or succinate or combinations thereof.

(4) Alternatively additional coolant additives such as silicates, nitrites, nitrates, phosphates, molybdates, anti-oxidants, thiazole derivatives, triazoles, polyacrylates, phosphonates and borates can be used to provide protection in the water phase.

(5) Examples of optional additional coolant are the typical coolant additives. These include but are not limited to silicates, nitrites, nitrates, phosphates, molybdates, anti-oxidants, thiazole derivatives, polyacrylates, phosphonates and borates that can be used to provide protection in the water phase.

EXAMPLES

Example 1

Comparative Example

(6) A running fluid was prepared comprising a major amount of ethylene glycol, 1.6 weight percent 2-ethyl hexanoic acid, 0.1 weight percent sebasic acid and 0.1% tolyltriazole and brought to a pH of 8.3.

Example 2

Comparative Example

(7) A running fluid was prepared comprising a major amount of water, 1.6 weight percent 2-ethyl hexanoic acid, 0.1 weight percent sebasic acid and 0.1% tolyltriazole and brought to a pH of 8.3.

(8) Note: Example 1 and 2 differ from each other only in the replacement of ethylene glycol by water. See results in the Table.

(9) It has been observed that by combining carboxylic acids with non-organic ammonium compounds like ammonium bicarbonate, or other non-organic ammonium products a good corrosion protection is present not only in the liquid phase but also a good corrosion protection is present towards the metals above the liquid level.

Example 3

Comparative Example

(10) A running fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid and 0.1% tolyltriazole and brought to a pH of 8.3.

Example 4

Demonstration of Current Invention

(11) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 0.1 weight percent ammonium bicarbonate and brought to a pH of 8.8.

Example 5

Comparative Example

(12) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 0.01 weight percent ammonium bicarbonate and brought to a pH of 8.8.

Example 6

Demonstration of Current Invention

(13) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 0.05 weight percent ammonium bicarbonate and brought to a pH of 8.8.

Example 7

Demonstration of Current Invention

(14) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 1.0 weight percent ammonium bicarbonate and brought to a pH of 8.8.

Example 8

Demonstration of Current Invention

(15) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 5.0 weight percent ammonium bicarbonate and brought to a pH of 8.8.

Example 9

Comparative Example

(16) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 0.1 weight percent ammonium bicarbonate and brought to a pH of 6.0.

Example 10

Comparative Example

(17) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 0.1 weight percent ammonium bicarbonate and brought to a pH of 8.2.

Example 11

Demonstration of Current Invention

(18) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 0.1 weight percent ammonium bicarbonate and brought to a pH of 9.7.

Example 12

Demonstration of Current Invention

(19) A running-in fluid was prepared comprising a major amount of water, 1.4 weight percent isononanoic acid, 0.1 weight percent sebasic acid, 0.1% tolyltriazole and 0.1 weight percent ammonium bicarbonate and brought to a pH of 12.0.

Example 13

Comparative Example, Based on Preferred Embodiments Disclosed in Prior Art

(20) A concentrate containing: 3 w % 2-ethylhexanoic acid; 0.175 w % Sodium nitrate; 0.45 w % Sodium nitrite; 0.6 w % stabilized silicate; 0.25 w % tolyltriazole; 0.3 w % polyvinylpyrolidone (15%); 0.03 w % defoamer; 0.05 w % ammonium molybdate; potassium hydroxide (45 w %) as pH controlling set to pH at 8.7 and rest monoethylene glycol. This concentrate is diluted with two volume of water before testing.

Example 14

Comparative Example, Based on Preferred Embodiments, Disclosed in Prior Art

(21) A concentrate containing: 1.75 w % succinic acid; 1.75 w % sebacic acid; 0.3 w % ammonium molybdate; 0.15 w % tolyltriazole; 0.15 w % benzotriazole; 0.6 w % benzoic acid; 1 w % water sodium hydroxide (50 w %) as pH controlling set to pH at 8.2 and rest monoethylene glycol. This concentrate is diluted 40 vol % with water before testing.

(22) Test Method

(23) To enable the evaluation of the running-in fluid, the following screening method was used. 100 ml of the targeted liquid was put into a glass vial containing a cast iron alloy coupon used in ASTM D-1384 glassware corrosion testing of coolants. The vial with content was placed in the oven for 1 hour at 90 C. After removal from the oven, the vial was allowed to cool down for 8 hours to room temperature. Seventy percent of the liquid was then removed, resulting in a partially immersed metal specimen. The partially immersed metal specimen remained for 1 hour at room temperature prior to being placed in an oven at 50 C. After this, the vial remained was refrigerated at 4 C. for 1 hour. The vial was taken out and placed at room temperature. The cycle 50 C. to 4 C. and back to room temperature was repeated again. Afterward, the metal samples were examined for corrosion. They were also examined for the position in the liquid as well as for the position in the vapor. The Table provides the results, demonstrating that the invention Examples provide the best corrosion protection in both the liquid and vapor phase.

(24) TABLE-US-00001 TABLE 1 Results Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 Ex 7 Result liquid 1 1 1 1 1 1 1 phase Result vapor 2 3 3 1 3 2 1 phase Ex 8 Ex 9 Ex 10 Ex 11 Ex 12 Ex 13 Ex 14 Result liquid 1 3 1 1 1 1 1 phase Result vapor 1 3 3 2 2 3 3 phase Legend 1 as new 2 superficial corrosion 3 heavily corroded
It is notable that the best performance is both the liquid and vapor phases occurred in Examples 4, 7, and 8. Examples 13 and 14, which are based on preferred embodiments cited in prior art, show heavy corrosion in the vapor phase.