Polythioether sealants with extended working time

{
  "publication_number": "US9683129B2",
  "country": "US",
  "kind": "B2",
  "title": "Polythioether sealants with extended working time",
  "abstract": "Thiol-terminated polythioether compositions and sealants prepared using the thiol-terminated polythioether compositions that exhibit extended working time and that rapidly cures at room temperature at the end of the working time are disclosed.",
  "claims": [
    "1. A composition comprising: a thiol-terminated polythioether prepolymer; an epoxy curing agent; and a latent tertiary amine catalyst selected from an encapsulated tertiary amine catalyst, a tertiary amine inclusion catalyst, and a combination thereof.",
    "2. The composition of claim 1, wherein the thiol-terminated polythioether prepolymer comprises a thiol-terminated polythioether comprising a backbone comprising the structure of Formula (1): - R 1 - [- S - (CH 2) 2 - O - [- R 2 - O -] m - (CH 2) 2 - S - R 1] n - (1) wherein, each R 1 is independently selected from a C 2-10 n-alkanediyl group, a C 3-6 branched alkanediyl group, a C 6-8 cycloalkanediyl group, a C 6-10 alkanecycloalkanediyl group, a heterocyclic group, a - [(- CHR 3 -) p - X -] q - (CHR 3) r - group, wherein each R 3 is selected from hydrogen and methyl; each R 2 is independently selected from a C 2-10 n-alkanediyl group, a C 3-6 branched alkanediyl group, a C 6-8 cycloalkanediyl group, a C 6-14 alkanecycloalkanediyl group, a heterocyclic group, and a - [(- CH 2 -) p - X -] q - (CH 2) r - group; each X is independently selected from O, S, and - NR -, wherein R is selected from hydrogen and methyl; m ranges from 0 to 50; n is an integer ranging from 1 to 60; p is an integer ranging from 2 to 6; q is an integer ranging from 1 to 5; and r is an integer ranging from 2 to 10.",
    "3. The composition of claim 1, wherein the thiol-terminated polythioether comprises a thiol-terminated polythioether of Formula (2a), a thiol-terminated polythioether of Formula (2b), or a combination thereof: HS - R 1 - [- S - (CH 2) 2 - O - (R 2 - O) m - (CH 2) 2 - S - R 1 -] n - SH (2a) {HS - R 1 - [- S - (CH 2) 2 - O - (R 2 - O) m - (CH 2) 2 - S - R 1 -] n - S - V′ - } z B (2b) wherein, each R 1 independently is selected from C 2-10 alkanediyl, C 6-8 cycloalkanediyl, C 6-14 alkanecycloalkanediyl, C 5-8 heterocycloalkanediyl, and - [(- CHR 3 -) p - X -] q - (- CHR 3 -) r -, wherein, p is an integer from 2 to 6; q is an integer from 1 to 5; r is an integer from 2 to 10; each R 3 is independently selected from hydrogen and methyl; and each X is independently selected from - O -, - S -, and - NR -, wherein R is selected from hydrogen and methyl; each R 2 is independently selected from C 1-10 alkanediyl, C 6-8 cycloalkanediyl, C 6-14 alkanecycloalkanediyl, and - [(- CHR 3 -) p - X -] q - (- CHR 3 -) r -, wherein p, q, r, R 3, and X are as defined as for R 1; m is an integer from 0 to 50; n is an integer from 1 to 60; B represents a core of a z-valent, polyfunctionalizing agent B(- V) z wherein, z is an integer from 3 to 6; and each V is a moiety comprising a terminal group reactive with a thiol; and each - V′ - is derived from the reaction of - V with a thiol.",
    "4. The composition of claim 1, wherein the thiol-terminated polythioether comprises the reaction product of reactants comprising: (a) a dithiol of Formula (3): HS - R 1 - SH (3) wherein, R 1 is selected from C 2-6 alkanediyl, C 6-8 cycloalkanediyl, C 6-10 alkanecycloalkanediyl, C 5-8 heterocycloalkanediyl, and - [- (CHR 3) p - X -] q - (CHR 3) r -; wherein, each R 3 is independently selected from hydrogen and methyl; each X is independently selected from - O -, - S -, - NH -, and - NR - wherein R is selected from hydrogen and methyl; p is an integer from 2 to 6; q is an integer from 1 to 5; and r is an integer from 2 to 10; and (b) a divinyl ether of Formula (4): CH 2 ═CH - O - [- R 2 - O -] m - CH═CH 2 (4) wherein, each R 2 is independently selected from C 1-10 alkanediyl, C 6-8 cycloalkanediyl, C 6-14 alkanecycloalkanediyl, and - [(- CHR 3 -) p - X -] q - (- CHR 3 -) r -, wherein p, q, r, R 3, and X are as defined for R 1; and m is an integer from 0 to 50.",
    "5. The composition of claim 4, wherein the reactants comprise (c) a polyfunctional compound comprising a polyfunctional compound B(- V) z, wherein, B represents a core of a z-valent, polyfunctionalizing agent B(- V) z wherein, z is an integer from 3 to 6; and each V is a moiety comprising a terminal group reactive with a thiol; and each - V′ - is derived from the reaction of - V with a thiol.",
    "6. The composition of claim 1, wherein the thiol-terminated polythioether prepolymer is characterized by an average thiol functionality from 2.05 to 2.8.",
    "7. The composition of claim 1, wherein the epoxy curing agent is selected from a Novolac epoxy resin, a bisphenol A/epichlorohydrin derived epoxy resin, and a combination thereof.",
    "8. The composition of claim 1, wherein the tertiary amine catalyst comprises an imidazole-epoxy adduct.",
    "9. The composition of claim 1, wherein the tertiary amine catalyst comprises an imidazole.",
    "10. The composition of claim 1, wherein the tertiary amine catalyst comprises 1,8-diazabicyclo[5.4.0]undec-7-ene.",
    "11. The composition of claim 1, formulated as a sealant.",
    "12. The composition of claim 11, characterized by a working time from about 40 hours to about 120 hours at room temperature.",
    "13. The composition of claim 11, which cures tack free within 24 hours to 48 hours at room temperature after the time the composition is no longer workable.",
    "14. The composition of claim 11, which cures to a Shore A hardness of 20 A within 24 hours to 48 hours at room temperature after the time the composition is no longer workable.",
    "15. A cured sealant prepared from the composition of claim 11.",
    "16. A method of sealing one or more surfaces, comprising: applying the composition of claim 11 to one or more surfaces; and curing the applied composition to seal the one or more surfaces."
  ],
  "description_excerpt": "The present disclosure relates to thiol-terminated polythioether compositions and sealants prepared from the thiol-terminated polythioether compositions having extended working time and fast cure rates.\n\nThiol-terminated polythioethers are well-known to be useful in aerospace sealant applications. Aerospace sealants must meet a number of challenging performance requirements that including adhesion, tensile strength, elongation, fuel resistance, and high temperature stability. Typical polythioether-based sealants are characterized by a relatively short working time of less than 12 hours.\n\nThiol-terminated polythioether-based sealant formulations exhibiting extended working time and that cure rapidly at the end of the working time are desired.\n\nEpoxy-cured, thiol-terminated polythioether-based sealants that include a latent amine catalyst exhibit extended working time and meet the demanding performance requirements of aerospace sealant applications.\n\nIn a first aspect, compositions are provided, comprising a thiol-terminated polythioether prepolymer, an epoxy curing agent, and a latent amine catalyst.\n\nIn a second aspect, a cured sealant prepared from a composition provided by the present disclosure are provided.\n\nIn a third aspect, methods of sealing one or more surfaces are provided, comprising applying a composition provided by the present disclosure to one or more surfaces, and curing the composition to seal the one or more surfaces.\n\nFIG. 1 is a graph showing the curing status with time of sealants provided by the present disclosure.",
  "cpc": [
    "C08G 75/02",
    "B01J 13/04",
    "B32B 27/00",
    "C08L 81/02",
    "C09D 181/02",
    "C09J 181/02",
    "C09K 3/1012"
  ],
  "ipc": [
    "C09D 181/02",
    "B32B 27/00",
    "C08G 75/02",
    "C09K 3/10"
  ],
  "assignees": [
    "PRC Desoto International Inc"
  ],
  "inventors": [
    "Juexiao Cai",
    "Renhe Lin"
  ],
  "filing_date": "2014-12-04",
  "publication_date": "2017-06-20",
  "grant_date": "2017-06-20",
  "priority_date": "2014-12-04",
  "application_number": "US-201414560289-A",
  "family_id": "55069086",
  "cited_by_count": 1,
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}