Curable sealant compositions, seal cap, and methods of making and using the same

A two-part curable sealant composition comprising a Part A composition and a Part B composition, wherein:

• the Part A composition comprises at least one polythiol;
• and
• the Part B composition comprises at least one unsaturated compound having at least two non-aromatic carbon-carbon double bonds, at least one carbon-carbon triple bond, or a combination thereof, wherein the Part A composition and the Part B composition collectively comprise components:
• a) x weight percent of at least one polythiol;
• b) y weight percent of at least one unsaturated compound having at least two non-aromatic carbon-carbon double bonds, at least one carbon-carbon triple bond, or a combination thereof;
• c) from 0.01 to 8 weight percent of at least one quaternary ammonium or phosphonium salt represented by the formula
• (R11)4M+X−
• wherein
• each R11 independently represents a hydrocarbyl group having from 1 to 30 carbon atoms;
• M+ represents N+ or P+;
• and
• X− represents an anion that is not detrimental to curing of the curable sealant composition;
• d) from 0.05 to 10 weight percent of at least one organic peroxide;
• and
• e) optionally from 0.01 to 10 weight percent of a photoinitiator system capable of generating free radicals upon exposure to actinic electromagnetic radiation,
• wherein the two-part curable sealant composition is free of a polyepoxide, and
• wherein x and y are positive real numbers, wherein x+y is in the range of 72 to 99, and wherein the weight percent ranges of the components a)-e) are based on the total weight of the components a)-e).

A seal cap comprising:

• a cap which defines an interior that is open at one end;
• and
• curable sealant composition disposed within the interior of the seal cap, wherein the curable sealant composition comprises components:
• a) x weight percent of at least one polythiol;
• b) y weight percent of at least one unsaturated compound having at least two non-aromatic carbon-carbon double bonds, at least one carbon-carbon triple bond, or a combination thereof;
• c) from 0.01 to 8 weight percent of at least one quaternary ammonium or phosphonium salt represented by the formula
• (R11)4M+X−
• wherein
• each R11 independently represents a hydrocarbyl group having from 1 to 30 carbon atoms;
• M+ represents N+ or P+;
• and
• X− represents an anion that is not detrimental to curing of the curable sealant composition;
• d) from 0.05 to 10 weight percent of at least one organic peroxide;
• and
• e) optionally from 0.01 to 10 weight percent of a photoinitiator system capable of generating free radicals upon exposure to actinic radiation,
• wherein the curable sealant composition is free of polyepoxide, and
• wherein x and y are positive real numbers, wherein x+y is in the range of 72 to 99, and wherein the weight percent ranges of the components a)-e) are based on the total weight of the components a)-e).