Curable amine, carboxylic acid flux composition and method of soldering

1. A curable flux composition, comprising, as initial components:

a resin component having at least two oxirane groups per molecule;

a carboxylic acid;

an amine fluxing agent represented by formula I:

wherein R 1 , R 2 , R 3 and R 4 are independently selected from a hydrogen, a substituted C 1-80 alkyl group, an unsubstituted C 1-80 alkyl group, a substituted C 7-80 arylalkyl group and an unsubstituted C 7-80 arylalkyl group; wherein R 7 and R 8 are independently selected from a C 1-20 alkyl group, a substituted C 1-20 alkyl group, a C 6-20 aryl group and a substituted C 6-20 aryl group or wherein R 7 and R 8 , together with the carbon to which they are attached, form a C 3-20 cycloalkyl ring optionally substituted with a C 1-6 alkyl group; wherein R 10 and R 11 are independently selected from a C 1-20 alkyl group, a substituted C 1-20 alkyl group, a C 6-20 aryl group and a substituted C 6-20 aryl group or wherein R 10 and R 11 , together with the carbon to which they are attached, form a C 3-20 cycloalkyl ring optionally substituted with a C 1-6 alkyl group; and, wherein R 9 is selected from a hydrogen, a C 1-30 alkyl group, a substituted C 1-30 alkyl group, a C 6-30 aryl group and a substituted C 6-30 aryl group; and,

optionally, a curing agent.

2. The curable flux composition of claim 1 , wherein the carboxylic acid is selected from the group consisting of a C 8-20 aliphatic mono carboxylic acids; C 2-20 aliphatic dicarboxylic acids; C 6-20 aromatic carboxylic acids; and, mixtures thereof.

3. The curable flux composition of claim 2 , wherein the carboxylic acid is selected from the group consisting of octanoic acid; nonanioc acid; undecanoic acid; dodecanoic acid; tridecanoic acid; tetradecanoic acid; pentadecanoic acid; hexadecanoic acid; heptadecanoic acid; stearic acid; hydroxy stearic acid; oleic acid; linoleic acid; α-linolenic acid; icosanoic acid; oxalic acid; malonic acid; succinic acid; malic acid; glutaric acid; adipic acid; pimelic acid; suberic acid; benzoic acid; phthalic acid; isophthalic acid; terephthalic acid; hemimellitic acid; trimellitic acid; trimesic acid; mellophanic acid; prehnitic acid; pyromellitic acid; mellitic acid; toluic acid; xylic acid; hemellitic acid; mesitylene acid; prehnitic acid; cinnamic acid; salicylic acid; benzoic acid; naphthoic acid; phenolphthalin; diphenolic acid and mixtures thereof.

4. The curable flux composition of claim 1 , wherein the flux composition exhibits a fluxing agent amine nitrogen to carboxylic acid content (—COOH) equivalent ratio of 1:1 to 20:1.

5. The curable flux composition of claim 1 , wherein the substitutions in the substituted C 1-80 alkyl group and the substituted C 7-80 arylalkyl group, from which R 1 , R 2 , R 3 and R 4 are selected, are selected from at least one of an —OH group, an —OR 5 group, a —COR 5 — group, a —COR 5 group, a —C(O)R 5 group, a —CHO group, a —COOR S group, an —OC(O)OR 5 group, a —S(O)(O)R 5 group, a —S(O)R 5 group, a —S(O)(O)NR 5 2 group, an —OC(O)NR 6 2 group, a —C(O)NR 6 2 group, a —CN group, a —N(R 6 )— group and a —NO 2 group; wherein R 5 is selected from a C 1-28 alkyl group, a C 3-28 cycloalkyl group, a C 6-15 aryl group, a C 7-28 arylalkyl group and a C 7-28 alkylaryl group; wherein R 6 is selected from a hydrogen, a C 1-28 alkyl group, a C 3-28 cycloalkyl group, a C 6-15 aryl group, a C 7-28 arylalkyl group and a C 7-28 alkylaryl group.

6. The curable flux composition of claim 1 , wherein one to three of R 1 , R 2 , R 3 and R 4 is(are) hydrogen.

7. The curable flux composition of claim 1 , wherein R 1 , R 2 , R 3 and R 4 are independently selected from a hydrogen, a —CH 2 CH(OH)R 18 and a —CH 2 CH(OH)CH 2 —O—R 18 group; wherein R 18 is selected from a hydrogen, a C 1-28 alkyl group, a C 3-28 cycloalkyl group, a C 6-28 aryl group, a C 7-28 arylalkyl group and a C 7-28 alkylaryl group; wherein R 7 and R 8 are both a methyl group; wherein R 10 and R 11 are both a methyl group; and, wherein R 9 is selected a methyl group and a phenyl group; and wherein zero to three of R 1 , R 2 , R 3 and R 4 is(are) hydrogen.

8. The curable flux composition of claim 4 , wherein one of R 1 and R 2 is hydrogen; and wherein one of R 3 and R 4 is hydrogen.

9. The curable flux composition of claim 1 , further comprising: a solder powder.

10. A process of forming an encapsulated metallurgical joint, comprising:

providing a curable flux composition according to claim 1 ;

providing a plurality of first electrical contacts;

providing a plurality of corresponding second electrical contacts;

providing a solder;

applying the curable flux composition to at least one of the plurality of first electrical contacts and the plurality of corresponding second electrical contacts;

placing the plurality of first electrical contacts in proximity to the plurality of corresponding second electrical contacts;

heating the solder above its reflow temperature forming a molten solder and exposing the molten solder to the plurality of first electrical contacts and the plurality of corresponding second electrical contacts;

displacing the curable flux composition from the plurality of first electrical contacts and the plurality of corresponding second electrical contacts with the molten solder and forming a plurality of electrical inter connects between the plurality of first electrical contacts and the plurality of corresponding second electrical contacts; and,

curing the resin component, encapsulating the plurality of electrical inter connects.