WO2018160691A1

WO2018160691A1 - Curable sealant composition

Info

Publication number: WO2018160691A1
Application number: PCT/US2018/020222
Authority: WO
Inventors: Anping Wang; Karl Matos; Ralph Dieter Maier; Elizabeth R. Burkhardt
Original assignee: Basf Se
Priority date: 2017-02-28
Filing date: 2018-02-28
Publication date: 2018-09-07

Abstract

A curable sealant composition includes a polysulfide having an -SH group, an isocyanate component, and a catalyst component including a first catalyst and an imidazolium catalyst, wherein the first catalyst has the structure (I): wherein R1 is in the 2, 3, 4, 5, or 6 position and R1 is chosen from H, CH3, CH2CH3, COCH3, OCOCH3, COCH2CH3, OCOCH2CH3, OCH3, and OCH2CH3. R2 is chosen from H, CH3, and CH2CH3. The imidazolium catalyst has the structure (II): wherein each of R3 and R5 is independently an organic radical having 1 to 20 carbon atoms, each of R4, R6, and R7 is independently H or an organic radical having 1 to 20 carbon atoms, and A- is an anion.

Description

CURABLE SEALANT COMPOSITION

FIELD OF THE DISCLOSURE

[0001] This disclosure generally relates to a curable sealant composition. More specifically, this disclosure relates a sealant composition that includes a polysulfide having an -SH group, an isocyanate component, and a particular catalyst component including a first catalyst and an imidazolium catalyst.

BACKGROUND

[0002] Polysulfide compositions in liquid and curable form are known in the art and have been used in a variety of industries. Typically, polysulfides are cured by an oxidoreduction reaction wherein manganese dioxide is used to cure the polysulfides over a number of days. However, the long curing time increases production times and costs and reduces efficiency.

[0003] The use of sealants in the manufacture or maintenance of aircraft has previously been a very complex process. The reason for this is the numerous joints having sealants, where sealants that often have very long processing times of up to 60 hours must be used. These methods typically require an extremely long time for complete curing and have required a very long tack-free time in the past in proportion to the length of the processing time. For example, an interlayer sealant of class C for the aviation field typically takes 60 to 70 days to achieve a Shore A hardness of 30 if the processing time is 60 hours. Furthermore, conventional type A and B sealants, which are usually applied over a surface or in the form of a bead for coating bolts, rivets or other structural elements typically need 2 to 5 hours to become tack-free if the processing time is 30 minutes, and typically take greater than 24 hours to achieve a Shore A hardness of 30. Therefore, there remains an opportunity for improvement.

SUMMARY OF THE DISCLOSURE

[0004] This disclosure provides a curable sealant composition that includes a polysulfide having an -SH group, an isocyanate component, and a catalyst component including a first catalyst and an imidazolium catalyst. The first catalyst has the structure:

wherein R¹ is in the 2, 3, 4, 5, or 6 position and R¹ is chosen from H, C¾, CH2CH3, COCH3, OCOCH3, COCH2CH3, OCOCH2CH3, OCH3, and OCH2CH3; and wherein R² is chosen from H, CH3, and CH2CH3. The imidazolium catalyst has the structure:

each of R⁴, R⁶, and R⁷ is independently H or an organic radical having 1 to 20 carbon atoms, and A^" is an anion.

[0005] This disclosure also provides a cured sealant formed from the curable sealant composition, a cured sealant including the polymerization product of the polysulfide and the isocyanate component reacted in the presence of the catalyst component, a curable sealant system including a first component including the polysulfide and the catalyst component and a second component including the isocyanate component. This disclosure also provides an article including a substrate and the cured sealant or curable sealant disposed on the substrate. This disclosure also provides a method of forming the curable sealant composition wherein the method includes the steps of providing the polysulfide, the isocyanate component, and the catalyst component and combining the polysulfide, the isocyanate component, and the catalyst component to form the curable composition. This disclosure further provides a method of forming the cured sealant wherein the method includes the steps of providing the polysulfide, the isocyanate component, and the catalyst component and combining the polysulfide, the isocyanate component, and the catalyst component such that the polysulfide polymerizes with the isocyanate component in the presence of the catalyst component to form the cured sealant. Even further, this disclosure provides a method of forming the article wherein the method includes the steps of providing the polysulfide, the isocyanate component, and the catalyst component and applying the polysulfide, the isocyanate component, and the catalyst component onto the substrate such that the polysulfide polymerizes with the isocyanate component in the presence of the catalyst component and forms the cured sealant disposed on the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Other advantages of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: [0007] Figure 1 is a block diagram of various non-limiting embodiments of this disclosure that shows how heat accelerated catalysts interact with various UV activated catalysts of this disclosure.

[0008] Figure 2 is a chart setting forth various options for physical properties of non-limiting Thiokol polysulfides that may be utilized in this disclosure.

[0009] Figure 3 A is a formula of a non-limiting Thioplast polysulfide that may be utilized in this disclosure.

[0010] Figure 3B is a formula of a second non-limiting Thioplast polysulfide that may be utilized in this disclosure.

[0011] Figure 3C is a chart setting forth various options for physical properties of non- limiting Thioplast polysulfides that may be utilized in this disclosure including reference back to Figures 3A and 3B.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0012] This disclosure provides a curable sealant composition (hereinafter described as the "composition."). The composition is curable and may be cured. After cure, the composition may be described as a curable sealant composition or simply as the cured composition. This disclosure describes an uncured composition, a partially cured composition, and a completely or fully cured composition. Accordingly, below, the terminology "composition" may describe any of the aforementioned types of compositions unless otherwise particularly stated.

[0013] The composition is not particularly limited and may be used in any industry, for example, in aeronautics, construction, for constructing and/or maintaining aircraft or spacecraft, in motor vehicles, in rail vehicles, in ships, in machines, in appliances and furniture, and, more particularly, for adhesive bonding and/or protection against corrosion of aircraft or spacecraft, motor vehicles, rail vehicles, ships, machines, appliances and furniture. In one embodiment, the composition is used as a sealant in an aircraft. In another embodiment, the composition is used as a sealant on a fuel-tank of an aircraft. In still another embodiment, the composition is used as a sealant on a fuel-tank of a vehicle such as a train, automobile, etc.

[0014] The composition includes, is, consists essentially of, or consists of, a polysulfide having an -SH group, an isocyanate component, and a particular catalyst component. Each of these is described in detail below. The terminology "consists essentially of describes non-limiting embodiments that are free of one or more polymers that are not, for example, polysulfides and/or polymeric isocyanates, free of one or more monomers that are not, for example, monomeric isocyanates, free of one or more catalyst components that are not those of this disclosure, and/or free of one or more additives known in the art and/or described below. The selection of which components to exclude from a composition "consisting essentially of the polysulfide, the isocyanate, and the catalyst component can be made by one of skill in the art.

Polysulfide:

[0015] The composition includes a polysulfide but may include two or more polysulfides or combinations of polysulfides, any one or more of which may be described below. For example, the composition may include at least one polysulfide, at least two polysulfides, etc. In various non-limiting embodiments described herein, the terminology "polysulfide" may include two or more polysulfides.

[0016] In various embodiments, the terminology "polysulfide" typically describes (one or more) polysulfide (homo)polymer(s). However, it is contemplated that (one or more) polysulfide (co)polymer(s) may also be used, either alone or in combination with the (one or more) (homo)polymers. The polysulfide may alternatively be described as a polythioether. In the art, various species of the genus polysulfides are polythioethers. Accordingly, the polysulfide may be further defined as polythioether or two or more polythioethers. Alternatively, the composition may include a polysulfide and a polythioether.

[0017] The polysulfide has an -SH group but otherwise is not particularly limited and maybe any in the art. The polysulfide may have a single -SH group or two or more -SH groups. One or more or all of the groups may be terminal or pendant. In various embodiments, the polysulfide is described as part of a class of chemical compounds including chains of sulfur atoms. In another embodiment, the polysulfide is a polymer having at least one S-S bond in its chain and an -SH group. The polysulfide of this disclosure is typically described as an organic polysulfide (as opposed to a sulfide anion (S_a ² ). In one embodiment, the polysulfide of this disclosure has the formula RS_aR(-SH)_b, wherein (a) is a number of 2 or greater, each R is independently an alkyl or aryl group, each -SH group is terminal or pendant, and (b) is a number of 1 or greater.

[0018] In other embodiments, the polysulfide is further defined as including a plurality of blocks each having the formula -R^Sx- wherein x is from 1 to 5 and R¹ is an alkyl group having 2 to 16 carbon atoms or an alkyl group 16 carbon atoms that further comprises one or more ether groups, and further having a terminal thiol group having the formula -R -SH, wherein R² is an alkyl group having 2 to 16 carbon atoms or an alkyl group having 2 to 16 carbon atoms that further comprises an ether-bond. [0019] In still other embodiments, the polysulfide is a polythioether that has the formula -R³- [-S-(CH₂)2-0-[-R⁴-0-]_m-(CH₂)2-S-R³-]„-. In this formula, each of R³ and R⁴ is independently a C₂-C6 n-alkylene group, a C3-C6 branched alkylene group, a C6-C₈ cycloalkylene group, a C₆-Cio alkylcycloalkylene group, or -[(-CH₂-)_p-X-]_q-(-CH₂-)_r, or -[(-CH₂-)_p-X-]_q-(-CH₂-)_r in which at least one CH₂ unit is substitute with a methyl group. Moreover, m is a number from 0 to 10, e.g. 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10, n is a number from 1 to 60, e.g. 5 to 55, 10 to 50, 15 to 45, 20 to 40, 25 to 35; p is a number from 2 to 6, e.g. 2, 3, 4, 5, or 6; q is a number from 1 to 5, e.g. 1, 2, 3, 4, or 5, and r is a number from 2 to 10, e.g. 2, 3, 4, 5, 6, 7, 8, 9, or 10. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0020] In further embodiments, the polysulfide is a polythioether that has the formula:

HS-(C₂H4-0-CH₂-0-C₂H4-(S-S)_2-8)_x-C₂H4-0-CH₂-0-C₂H4-SH wherein x is from 1 to 200, e.g. 5 to 195, 10 to 190, 15 to 185, 20 to 180, 25 to 175, 30 to 170, 35 to 165, 40 to 160, 45 to 155, 50 to 150, 55 to 145, 60 to 140, 65 to 135, 70 to 130, 75 to 125, 80 to 120, 85 to 1 15, 90 to 110, 95 to 105, or 95 to 100. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0021] In further embodiments, the polysulfide is a polythioether that has the formula:

H(S-C₂H₄-0-CH₂-0-C₂H₄-S)_zH

wherein z is from 7 to 43, e.g. 10 to 40, 15 to 35, 20 to 30, or 20 to 25.

[0022] In further embodiments, the polysulfide has the formula: HS-(R-SS)_t-R-SH, wherein each R is independently a C₂-C6 n-alkylene group, a C3-C6 branched alkylene group, a C6-C₈ cycloalkylene group, or a C6-C₁₀ alkylcycloalkylene group and wherein t is from 5 to 40, e.g. 10 to 35, 15 to 30, 20 to 30, or 25 to 30. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0023] In further embodiments, the polysulfide has the formula: HS-(R-SS)_q-CH₂CH((SS- R)_v-SH)-CH₂-(SS-R)_r-SH, wherein each R is independently a C₂-C6 n-alkylene group, a C3- Ce branched alkylene group, a C6-C₈ cycloalkylene group, or a C6-C10 alkylcycloalkylene group, wherein q+v+r is from 5 to 40, e.g. 10 to 35, 15 to 30, 20 to 30, or 25 to 30. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0024] In further embodiments, the polysulfide is a polythioether that has the formula:

HS-R-(0-CH₂-CH₂-S-CH₂-CH₂-0-CH-CH₂-S-CH₂-0-CH₂-CH₂-S-CH₂-CH₂-)-R-SH, wherein each R is independently as described above. [0025] In still other embodiment the polysulfide may be described as a long-chain polymer with a weight average molecular weight of 2800 to 9000 g/mol, e.g. those of Thioplast G131 or with a weight average molecular weight of 3300 to 5000 g/mol such as Thioplast G10, Thioplast G12, Thioplast Gl, Thiokol LP 32, and/or Thiokol LP 12. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0026] Alternatively, the polysulfide may be described as a short-chain polymer with a weight average molecular weight of 100 to 3200 g/mol, e.g. from 400 to 2800 g/mol and/or from 500 to 1200 g/mol, such as, for example, Thiokol LP3, Thioplast G4, Thioplast G22 or Thioplast G44.

[0027] In other embodiments, both long-chain polymers with a weight average molecular weight of 2800 to 9000 g/mol or 3300 to 5000 g/mol and short-chain polymers with a weight average molecular weight of 400 to 2800 g/mol or from 500 to 1200 g/mol, are used, e.g. in a weight ratio of 25: 1 to 0.5:1, from 10:1 to 1 :1 or from 6: 1 to 2:1. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0028] In still other embodiments, the polysulfide is described as a liquid polymer having a weight average molecular weight of from 100 to 7500 g/mol or from 500 to 6000 g/mol or from 1000 to 3000 g/mol. Alternatively, the polysulfide may have a weight average molecular weight of from 1,000 to 7,500, from 1,500 to 6,000, from 2,000 to 5,500, from 2,500 to 5,000, from 3,000 to 4,500, or from 3,500 to 4,000, g/mol. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0029] In further embodiments, the polysulfide has a total sulfur content of from 1 to 50 wt %, 2 to 45 wt % or 10 to 38 wt %. In other embodiments, the polysulfide has an average functionality of -SH groups of greater than 2, greater than or equal to 2, 2, less than 2, or less than or equal to 2, e.g. from 1.5 to 2.5 or 1.9 to 2.2. In various embodiments, the average functionality is from 1.5 to 2 or 0.8 to 1.5. In other embodiments, the polysulfide has an average glass transition temperature Tg of from -80 to -30°C or -60 to -40°C, measured according to AITM 1-0003 Airbus Industry Test Method of June 1995. In various non- limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated. [0030] In various embodiments, the polysulfide is chosen from one or more of the polysulfides described in one or more of Figures 2 and 3A-3C. Any and all values and ranges of values including and between any one or more of the values set forth in these Figures are hereby expressly contemplated herein in one or more non-limiting embodiments.

[0031] The amount of the polysulfide in the composition is not particularly limited. In various embodiments, the polysulfide is present in the composition in an amount of from 1 to 80, from 1 to 30, from 5 to 30, from 5 to 80, from 60 to 80, or from 30 to 80, parts by weight per 100 parts by weight of the composition. In other embodiments, the polysulfide is present in an amount of from 50 to 80, 60 to 80, 55 to 75, 60 to 70, or 65 to 70, parts by weight per 100 parts by weight of "Part A", as described below. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

Isocyanate:

[0032] The isocyanate is not particularly limited and may be any known in the art. The isocyanate maybe alternatively described as an isocyanate component that itself includes two or more individual isocyanates.

[0033] The isocyanate may be, include, consist essentially of, or consist of, any isocyanate known in the art, e.g. aliphatic isocyanates, aromatic isocyanates, polymeric isocyanates, or combinations thereof. The isocyanate may be, include, consist essentially of, or consist of, more than one different isocyanate, e.g., polymeric diphenylmethane diisocyanate and 4,4'- diphenylmethane diisocyanate. In various embodiments, the isocyanate is chosen from diphenylmethane diisocyanates (MDIs), polymeric diphenylmethane diisocyanates (pMDIs), toluene diisocyanates (TDIs), hexamethylene diisocyanates (HDIs), isophorone diisocyanates (IPDIs), and combinations thereof.

[0034] In various embodiments, the isocyanate typically includes, but is not limited to, isocyanates, diisocyanates, polyisocyanates, and combinations thereof. In one embodiment, the isocyanate includes an n-functional isocyanate. In this embodiment, n is a number typically from 2 to 5, more typically from 2 to 4, still more typically of from 2 to 3, and most typically about 2. It is to be understood that n may be an integer or may have intermediate values from 2 to 5. The isocyanate typically includes an isocyanate selected from the group of aromatic isocyanates, aliphatic isocyanates, and combinations thereof. In another embodiment, the isocyanate includes an aliphatic isocyanate such as hexamethylene diisocyanate (HDI), dicyclohexyl-methylene-diisocyanate (H12MDI), isophorone- diisocyanate, and combinations thereof. If the isocyanate includes an aliphatic isocyanate, the isocyanate may also include a modified multivalent aliphatic isocyanate, i.e., a product which is obtained through chemical reactions of aliphatic diisocyanates and/or aliphatic polyisocyanates. Examples include, but are not limited to, ureas, biurets, allophanates, carbodiimides, uretonimines, isocyanurates, urethane groups, dimers, trimers, and combinations thereof. The isocyanate may also include, but is not limited to, modified diisocyanates employed individually or in reaction products with polyoxyalkyleneglycols, diethylene glycols, dipropylene glycols, polyoxyethylene glycols, polyoxypropylene glycols, polyoxypropylenepolyoxethylene glycols, polyesterols, polycaprolactones, and combinations thereof. [0035] Alternatively, the isocyanate can include an aromatic isocyanate. If the isocyanate includes an aromatic isocyanate, the aromatic isocyanate typically corresponds to the formula R'(NCO)z wherein R' is aromatic and z is an integer that corresponds to the valence of R'. Typically, z is at least two. Suitable examples of aromatic isocyanates include, but are not limited to, tetramethylxylylene diisocyanate (TMXDI), 1 ,4-diisocyanatobenzene, 1,3- diisocyanato-o-xylene, 1,3-diisocyanato-p-xylene, 1,3-diisocyanato-m-xylene, 2,4- diisocyanato-l-chlorobenzene, 2,4-diisocyanato-l-nitro-benzene, 2,5-diisocyanato-l- nitrobenzene, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanate, 1 ,5 -naphthalene diisocyanate, l-methoxy-2,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'- diphenylmethane diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, triisocyanates such as 4,4',4"-triphenylmethane triisocyanate polymethylene polyphenylene polyisocyanate and 2,4,6-toluene triisocyanate, tetraisocyanates such as 4,4'-dimethyl-2,2'- 5,5'-diphenylmethane tetraisocyanate, toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, corresponding isomeric mixtures thereof, and combinations thereof. Alternatively, the aromatic isocyanate may include a triisocyanate product of m-TMXDI and 1,1 ,1-trimethylolpropane, a reaction product of toluene diisocyanate and 1,1,1-trimethyolpropane, and combinations thereof. In one embodiment, the isocyanate includes a diisocyanate selected from the group of methylene diphenyl diisocyanates, toluene diisocyanates, hexamethylene diisocyanates, H12MDIs, and combinations thereof.

[0036] The isocyanate may be an isocyanate pre-polymer. The isocyanate pre-polymer may be a reaction product of an isocyanate and a polysulfide, polythioether, polyol and/or a polyamine. Alternatively, the isocyanate may be a prepolymer that is the reaction product of an isocyanate and the polysulfide. The isocyanate used in the pre-polymer can be any isocyanate as described above. The polyol used to form the pre-polymer may be any polyol having a number average molecular weight of 400 g/mol or greater. For example, polyetherols, polyesterols, and combinations thereof can be used. Castor oil can also be used.

[0037] Referring back, the isocyanate typically has an NCO content of from 3 to 50, alternatively from 3 to 33, alternatively from 18 to 30, weight percent when tested in accordance with DIN EN ISO 11909, and a viscosity at 25°C of from 5 to 2000, alternatively from 100 to 1000, alternatively from 150 to 250, alternatively from 180 to 220, mPa^»sec when tested in accordance with DIN EN ISO 3219. In alternative embodiments, all values and ranges of values between and including the aforementioned values are hereby expressly contemplated.

[0038] In various embodiments the isocyanate is, includes, consists essentially of, or consists of, monomeric and polymeric isocyanate. For example, in one embodiment the isocyanate includes polymeric diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and has an NCO content of about 33.5 weight percent. Alternatively, in another embodiment, the isocyanate includes polymeric diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and has an NCO content of about 31.3 weight percent.

[0039] The isocyanate can be utilized in the composition in any amount. In various embodiments, the isocyanate is utilized in an amount of from 10 to 100, 20 to 90, 30 to 80, 40 to 70, or 50 to 60, weight percent based on a total weight of the composition. In other embodiments, the isocyanate is present in an amount of from 80 to 100, from 85 to 95, or from 90 to 65, parts by weight per 100 parts by weight of "Part B", as described below. In various embodiments, the isocyanate content is from 10 to 100% depending on additive choice and prepolymer composition. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

Catalyst Component:

[0040] The composition also includes the catalyst component. The catalyst component includes a first catalyst and an imidazolium catalyst. The first catalyst has the structure:

wherein R¹ may be in the 2, 3, 4, 5, or 6 position and R¹ is chosen from H, C¾, CH2CH3, COCH3, OCOCH3, COCH2CH3, OCOCH2CH3, OCH3, and OCH2CH3. For example, R¹ may be in the ortho, meta, or para, positions. Moreover, R may be H, or CH3, or CH2CH3, or COCH3, or OCOCH3, or COCH2CH3, or OCOCH2CH3, or OCH₃, or OCH2CH3. Moreover, R² is chosen from H, CH3, and CH2CH3. Said differently, R² may be H, or CH3, or CH2CH3. In various embodiments, R¹ is H, OCCH3 or OCOCH3 and R² is H. Alternatively mixtures of catalysts may be used.

[0041] In other embodiments, R¹ and R² are both hydrogen atoms. In other embodiments, R¹ is OCOCH3 and R² is a hydrogen atom. Alternatively, R¹ and R² are both hydrogen atoms and a second catalyst is utilized of the same general structure wherein R¹ is OCOCH3 and R² is a hydrogen atom.

[0042] Due to the variation in R¹ and R², in some embodiments, the first catalyst may have a starting pH from 7.5 to 9.5 which may be customized to influence pot life. In one embodiment, the first catalyst has a starting pH of 8. In another embodiment, the catalyst has a starting pH of 9. One or a combination of more than one first catalyst can be used. In various embodiments, when a single first catalyst is used, it is used in an amount from 0.05% to 5%, e.g. about 0.5%. In another embodiment, two first catalysts are used in an amount of from 0.05% to 2.5% for each individual catalyst, with a typical value of 0.15% and 0.2% for each catalyst on its own.

[0043] First catalysts with different pH may used to adjust bulk cure time and pot life. For example, first catalysts with higher pH can be used to increase bulk cure time while those with lower pH can be used to increase pot life. Additives that can change initial pH can also used to adjust bulk cure time and pot life. For example, first catalyst A with an initial pH of 8 and first catalyst B with an initial pH of 9 can be used in different portions for the above mentioned adjustments. First catalyst combinations of 0 wt% to 100 wt% of first catalyst A and 0 wt% to 100 wt% of first catalyst B can be used. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0044] In various embodiments, the first catalyst operates in the following mechanism:

For example, the first catalyst may form an amidine which can in and of itself act as a catalyst. The amidine may have a pH of 12, 13, or 14 and can catalyst a thiol-isocyanate reaction, e.g. with accelerated kinetic rate.

[0045] In one embodiment, such as shown in Figure 1 , UV catalyst 1 is

wherein R¹ is H and R² is OCOCH₃.

[0046] As also shown in Figure 1, UV catalyst 2 is

wherein both R¹ and R² are H.

[0047] The imidazolium catalyst has the structure:

[0048] For example, each of R³, R⁴, R⁵, R⁶, and R⁷ may independently be an organic radical having 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms. Any organic radical may be utilized, e.g. linear, branched, cyclic, and acyclic organic radicals. The organic radical may be aliphatic or aromatic, or may include both aromatic and aliphatic groups. Moreover, the organic radical may include only carbon and hydrogen or may include carbon, hydrogen, and one or more heteroatoms such as oxygen atoms, nitrogen atoms, sulfur atoms, and/or phosphorus atoms. In other embodiments, the organic radical may include one or more functional groups such as hydroxyl groups, ether groups, ester groups, or carbonyl groups. It is contemplated that the organic radical may be free of one or more of any non- carbon and non-hydrogen heteroatoms including, but not limited to, those described above. Moreover, it is contemplated that the organic radical may be free of one or more functional groups including, but not limited to, those described above. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0049] In other embodiments, each of R³ and R⁵ is independently a hydrocarbon radical which, apart from carbon and hydrogen, may further include hydroxyl groups, ether groups, ester groups or carbonyl groups. In still other embodiments, each of R³ and R⁵ includes no non-carbon or non-hydrogen heteroatoms, e.g., oxygen or nitrogen. In a further embodiment,

1 3

each of R and R is an aliphatic hydrocarbon radical.

[0050] Non-limiting examples of suitable hydrocarbon radicals include a phenyl group, benzyl group, a benzyl or phenyl group substituted by one or more Q to C₄ alkyl groups, or a mesityl group, alkyl groups, and/or alkenyl groups, or combinations thereof.

3 5

[0051] In still other embodiments, each of R and R is independently a Ci to Ci₈ alkyl group, a Ci to Ci6 alkyl group, a Ci to Ci₄ alkyl group, a Ci to Ci₂ alkyl group, a Ci to Cio alkyl group, a Ci to Ce alkyl group, or a Ci to C₄ alkyl group. [0052] In further embodiments, each of R³ and R⁵ is independently a methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert-butyl group. Alternatively, each of R³ and R⁵ is independently a methyl, ethyl n-propyl, or n-butyl group. In other embodiments, R³ is a Q to Ce alkyl group or a Ci to C₄ alkyl group. R⁵ may be, for example, a methyl group.

[0053] Referring back, R⁴ may be an H atom. Alternatively, R⁴ may be an alkyl group such as a Ci to Ci₈ alkyl group, a Q to Ci6 alkyl group, a Q to Q₄ alkyl group, a Q to Ci₂ alkyl group, a Ci to Cio alkyl group, a Ci to Ce alkyl group, or a Q to C₄ alkyl group.

6 7

[0054] In other embodiments, each of R and R may independently be a hydrogen atom or an organic radical having 1 to 10 carbon atoms. For example, each of R⁶ and R⁷ may independently be an organic radical having 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms and may be any of those described above. Any organic radical may be utilized, e.g. linear, branched, cyclic, and acyclic organic radicals. The organic radical may be aliphatic or aromatic, or may include both aromatic and aliphatic groups. Moreover, the organic radical may include only carbon and hydrogen or may include carbon, hydrogen, and one or more heteroatoms such as oxygen atoms, nitrogen atoms, sulfur atoms, and/or phosphorus atoms. In other embodiments, the organic radical may include one or more functional groups such as hydroxyl groups, ether groups, ester groups, or carbonyl groups. It is contemplated that the organic radical may be free of one or more of any non-carbon and non-hydrogen heteroatoms including, but not limited to, those described above. Moreover, it is contemplated that the organic radical may be free of one or more functional groups including, but not limited to, those described above. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0055] In other embodiments, each of R⁶ and R⁷ is independently a hydrocarbon radical which, apart from carbon and hydrogen, may further include hydroxyl groups, ether groups, ester groups or carbonyl groups. In still other embodiments, each of R⁶ and R⁷ includes no non-carbon or non-hydrogen heteroatoms, e.g., oxygen or nitrogen. In a further embodiment,

6 7

each of R and R is independently an aliphatic hydrocarbon radical.

[0056] Non-limiting examples of suitable hydrocarbon radicals include a phenyl group, benzyl group, a benzyl or phenyl group substituted by one or more Q to C₄ alkyl groups, or a mesityl group, alkyl groups, and/or alkenyl groups, or combinations thereof.

6 7

[0057] In still other embodiments, each of R and R is independently a Q to Ci₈ alkyl group, a Ci to Ci6 alkyl group, a Ci to Ci₄ alkyl group, a Ci to C₁₂ alkyl group, a Ci to Cio alkyl group, a Ci to Ce alkyl group, or a Ci to C₄ alkyl group. In further embodiments, each of R⁶ and R⁷ is independently a methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert-butyl group. Alternatively, each of R⁶ and R⁷ is independently a methyl, ethyl n-propyl, or n-butyl group. In one embodiment, R⁶ and R⁷ are each H atoms. In another embodiment, R⁴, R⁶, and R⁷ are each H atoms. In further embodiments, each of R⁴, R⁶ and R⁷ are hydrogen. In another embodiment, R 3 and R 5 are the same.

[0058] In another embodiment, at least one of the two radicals R³ and R⁵ has at least 4 carbon atoms, e.g. and one or more is n-butyl, hexyl or 2-ethylhexyl. In a further embodiment, R¹ and R³ are the same and are each, for example, methyl, ethyl or n-butyl.

[0059] Examples of suitable imidazolium ions include, but are not limited to, l,2-dimethyl-3- propylimidazolium, l-ethyl-2,3-dimethylimidazolium, l-butyl-2,3-dimethylimidazolium, 1- benzyl-3-methylimidazolium, 3-ethyl-l-methylimidazolium, l-propyl-3-methylimidazolium, 3 -n-butyl- 1 -methylimidazolium, 1 -hexyl-3 -methylimidazolium, 1 -methyl-3 - octylimidazolium, l-decyl-3-methylimidazolium, l-dodecyl-3 -methylimidazolium, 1,3- diethylimidazolium, 1,3-diisopropylimidazolium, 1,3-di-n-butylimidazolium, 1,3- dihexylimidazolium, and 1,2,3,4,5-pentamethylimidazolium. In various embodiments, the imidazolium ion is chosen from 3-ethyl-l-methylimidazolium, 1,3-diethylimidazolium, 1,3- dihexylimidazolium, and 1,3-di-n-butylimidazolium.

[0060] Referring now to the anion A^", this anion is typically an aromatic or heteroaromatic carboxylate anion. In one embodiment, A^" is an aromatic carboxylate anion. Suitable non- limiting examples of the anion A^" are the anions of aromatic carboxylic acids such as benzoic acid, 2-, 3- or 4-methylbenzoic acid, 3,5-dimethylbenzoic acid, 2-, 3- or 4-chlorobenzoic acid, 2,3-, 2,4-, 2,5- or 3,4-dichlorobenzoic acid, 2-, 3- or 4-cyanobenzoic acid, 2-, 3- or 4- methoxybenzoic acid, 2-, 3- or 4-nitrobenzoic acid, 2,4-dinitrobenzoic acid, salicylic acid, 3- hydroxy-4-methylbenzoic acid, acetylsalicylic acid, 2-, 3- or 4-aminobenzoic acid, 4- dimethylaminobenzoic acid, 4-diethyl-aminobenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene- 1 -carboxylic acid, naphthalene-2-carboxylic acid, anthracene- 9-carboxylic acid, pyridine-2-, -3- or -4-carboxylic acid, indole-5-carboxylic acid, and nicotinic acid. In one embodiment, the anion is an anion of benzoic acid. In various embodiments, the anion is chosen from acetate, thocyanate, tetrafluoroborate, dicyanamide, trifluoromethanesulfonate, methylsulfate, diethylphosphate, ethylsulfate, chloride, and methane sulfonate .

[0061] The synthesis of such imidazolium ions with carboxylate anions as a counterion is described, for example, in WO 2009/040242. The synthesis of the symmetrical imidazolium salts is described, for example, in WO 2009/074535 A2. The synthetic workup may be as described in WO 2009/027250 A2. The synthesis and identity of the catalyst may also be as described in US 20150322289. These documents are expressly incorporated herein in their entirety in various non-limiting embodiments.

[0062] In various embodiments, R⁴=R⁶=R⁷=H and R³ and R⁵ are n-alkyl radicals with chain lengths in accordance with the table below, and the anion is an aromatic or heteroaromatic.

In other embodiments, R may be n-alkyl radical with chain length as per the table below:

[0063] In various embodiments, the catalyst is l-methyl-3-vinylimidazolium carboxylate, more particularly l-methyl-3-vinylimidazolium benzoate; l-benzyl-3-methylimidazolium carboxylate, more particularly l-benzyl-3-methylimidazolium benzoate.

[0064] In other embodiments, each of R¹ and R³ is independently an organic radical having 1 to 20, e.g. 1 to 6, carbon atoms and that optionally includes one or more heteroatoms such as oxygen atoms, nitrogen, sulfur atoms, or phosphorus atoms. The organic radical may also include or be a functional group, e.g. a hydroxyl group, an ether group, an ester group, or a carbonyl group. These groups could be aliphatic or aromatic but are typically aliphatic. Each of R², R⁴ and R⁵ is independently a hydrogen atom or a hydrocarbon having 1 to 20 carbon atoms. In still other embodiments, R³ is ethyl, R⁴ is H; R⁵ is methyl; R⁶ is H; R⁷ is H, and A^" is benzoate.. The catalyst may be EMIMBz, which is l-Ethyl-3-methylimidazolium benzoate.

Additive:

[0065] The composition may also include one or more additives or be free of any one or more additives, such as those described below. For example, in various embodiments, the composition includes a UV photosensitizer. Any type known in the art may be used. For example, the UV photosensitizer may be used such that the composition may cure in the UVA, UVB, or UVC range. In still further embodiments, mixtures of photosensitizers and/or photoinitiators may be used to adjust the absorption wavelength(s) of the composition or to shift the absorption edge and/or the absorption range of the composition. Examples of suitable photosensitizers include, but are not limited to, DAROCUR® BP (Benzophenone), Quantacure BMS (4-(4-Methylphenylthio)benzophenone), DAROCUR® ITX (Isopropylthioxanthone), and combinations thereof. In various other embodiments, the photosensitizer is utilized in amounts of from 0.1 to 5, 0.5 to 4.5, 1 to 4, 1.5 to 3.5, 2 to 3, or 2.5 to 3.5, parts by weight per 100 parts by weight of the composition. In other embodiments, the photosensitizer is present in an amount of from 0.1 to 1, 0.2 to 0.9, 0.3 to 0.8, 0.4 to 0.7, or 0.5 to 0.6, parts by weight per 100 parts by weight of "Part A" and/or "Part B", as described below. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0066] Further, fillers based on magnesium silicate hydrate such as, for example, talc, based on aluminum hydroxide such as, for example, Al(OH)3, based on a feldspar, based on quartz powder and/or based on a calcium silicate and/or aluminum silicate may be used and may have a particle size from 1 to 20 micrometers. Adding one or more fillers may serve to improve the mechanical properties of the composition. In various embodiments, the fillers are chosen from calcium silicate, magnesium silicate hydrate, aluminum silicate, quartz powder and/or aluminum hydroxide such as, for example, aluminum trihydrate. Fillers based on CaC03, Ti0₂, carbon black and/or BaS0₄ as well as fillers with a significant Fe content and/or containing additional heavy metals may be used.

[0067] Plasticizers such as, but not limited to, aliphatic oils, waxes, fatty acid salts, resins derived from alkylated phenols and esters, and combinations thereof. In other embodiments, the composition includes one or more fillers such as, but not limited to, microspheres, polystyrene foam, polyacrylates, polyolefins, silica, aluminum/silica, aluminum silicate, calcium carbonate, coated polyvinylidene, calcium silicates, fumed silica, precipitated silica, polyethylene, Calcium carbonate, carbon black, calcined clay, talc, silica, silicate fillers, rutile titanium dioxide, zeolites, and combinations thereof. In still other embodiments, the composition includes one or more adhesion promoters such as, but not limited to, methylon AP-108, Duerz 16674, Bakelite BRL 3741, Resinex 468, silanes, phenolic resins, polysulfides, epoxy functional molecules, and combinations thereof. In further embodiments, the composition includes surfactants, such as those known in the art, thixotropic agents such as sepiolite and those known in the art, solvents such as organic solvents, ethyl acetate, terphenyls, hydrogenated terphenyls, toluene, and those known in the art, and/or pigments such as titanium dioxide, zinc sulfide, carbon black, organic and inorganic pigments, and those known in the art, and combinations thereof. In further embodiments, the composition includes photosensitizers and/or photo initiators, or combinations thereof. Moreover, the composition maybe free of any one or more such additives.

[0068] In still other embodiments, the composition may include or be free of one or more of calcium carbonate, butanone, toluene, titanium dioxide, Ethanethiol, 2,2,-thiobis-l reaction products with reduced l,l'-[methylenebis(oxy)]bis [2-chloroethane]-sodium sulfide (Na2 (Sx)-l,2,3-trichloropropane polymer, ethyl acetate, hydrogenated Terphenyls, Zeolites, quarter- and higher, partially hydrogenated Polyphenyls, Talc, carbon black, magnesium carbonate, 1,3-diphenylguanidine, bis(piperidinothiocarbonyl) tetrasulphide, photo initiators, photosensitizers such as benzophenone, isopropyl thioxanthone, aluminum silicate, phenolic resins, Sepiolite, NaAl-based zeolite, phosphorous acid esters, monomeric isocyanates, e.g. based on MDI, pyrogenic silica, and/or combinations thereof.

[0069] Lightweight fillers, in particular those based on polyurethane including their copolymers, polyamide wax and/or polyolefin wax may also be used. Lightweight fillers may also be used to reduce the density of the composition and/or sealant. Alternatively or additionally, hollow filing bodies may also be used.

[0070] Thixotropy agents, in particular based on feldspar, silicic acid/silica, sepiolite and/or bentonite may be used to adjust rheological properties, in particular for thixotropic behavior, of the composition.

[0071] Plasticizers, in particular based on an adipate, a benzoate, a citrate, a phthalate, an ester of a polyethylene glycol, and/or a terphenyl may be used, for example, to increase the flexibility of the composition and/or sealant.

[0072] Adhesion promoters, in particular those based on a phenolic resin, a resol and/or a silane/silanol/siloxane, e.g. mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, methacryloxymethyl trimethoxysilane and/or (methacryloxymethyl)methyldimethoxysilane and/or a bis-silylsilane may be used to improve the adhesion of the composition and/or sealant to a substrate.

[0073] Anti-aging agents may also be used such as sterically hindered phenols, phenyleneamine and/or hindered amine light stabilizers such as 4,6-bis(dodecylthiomethyl)- o-cresol, ethylene-bis(oxyethylene)bis(3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate- , thiodiethylene-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate) and/or phenylene amines such as, for example, N-isopropyl-N'-phenyl-p-phenylenediamine. Anti-aging agents may be used to scavenge the free radicals formed due to aging processes involving the composition and may contribute to delaying and/or preventing aging such as yellowing or embrittlement of the composition and/or sealant.

[0074] Water scavengers, e.g. those based on an organofunctional alkoxysilane, based on a zeolite such as an alkali aluminum zeolite and/or based on a mono functional isocyanate may also be used.

[0075] Flame retardants, in particular those based on phosphate esters, based on ammonium polyphosphate, based on melamine, based on aluminum hydroxide and/or based on magnesium hydroxide may also be used to improve the fire prevention behavior of the composition and/or sealant such as, for example, to delay the onset of burning of the sealant, to spontaneously terminate the burning process and/or to reduce the formation of smoke.

[0076] Vulcanization promoters may also be used such as diphenylguanidine, thiuram, and/or sulfur (e.g. sulfur paste).

[0077] In various embodiments, at least one organic solvent, in particular based on an ester and/or an ether such as, for example, ethyl acetate and/or monopropylene glycol monomethyl ether can be used.

[0078] The one or more additives may be present in an amount of from 0 to 40, 0.1 to 10, from 0.1 to 5, or from 0.1 to 2, parts by weight per 100 parts by weight of the composition or per 100 parts by weight of "Part A" and/or "Part B", described below. In other embodiments, the one or more additive may be present in an amount of from 0.01 to 5, from 0.1 to 5, or from 0.1 to 2, parts by weight per 100 parts by weight of the composition or per 100 parts by weight of "Part A" and/or "Part B", described below. In still other embodiments, the one or more additive may be present in an amount of from 0.01 to 40, from 0.2 to 1, from 10 to 40, from 1 to 10, or from 5 to 10, parts by weight per 100 parts by weight of the composition or per 100 parts by weight of "Part A" and/or "Part B", described below. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

Sealant System:

[0079] This disclosure also provides a sealant system, e.g. a two-part system. In one embodiment, this system includes a first component including, consisting essentially of, or consisting of, the polysulfide and the catalyst, and a second component including, consisting essentially of, or consisting of, the isocyanate and optionally one or more additives. In another embodiment, this system includes a first component including, consisting essentially of, or consisting of, the polysulfide and one or more optional additives, and a second component including, consisting essentially of, or consisting of, the isocyanate and the catalyst. The terminology "consisting essentially of describes that the first and/or second component is free of other polymers, monomers, catalysts, etc. In various embodiments, the first component and the second component are utilized in an amount of 1 :1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1, or vice versa, or any combinations thereof. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated. The first component may be alternatively described as "Part A" as first introduced above. The second component may be alternatively described as "Part B" also introduced above. For example, the polysulfide and the isocyanate component are present in the composition in a weight ratio of from 16:1 to 2:1, referred as part A to Part B ratio for the two part sealant system.

Sealant:

[0080] The disclosure also provides a sealant, which may be described as the result of the composition after cure. Alternatively, the sealant may be described as a partially cured composition.

[0081] The composition cures typically using the mechanism based on the catalyst. For example, the catalyst itself can catalyze the reaction of the polysulfide and the isocyanate at room temperature. UV light irradiation can also trigger the catalyst to release an amidine that can greatly accelerate a surface cure at depths of less than 200 um on a surface, e.g. as shown in Figure 1. Moreover, diffusion of the amidine in the composition matrix can surface cure up to 7mm. The heat generated from a UV source or an external heat source can also accelerate the reaction of the polysulfide and the isocyanate and diffusion of amidine and therefore can improve bulk cure. In addition, the catalyst of this disclosure has a different pH level than those of the art which allows for bulk cure rates to be customized by using catalysts with differing pH , e.g. from 7 to 10 or 8 to 9. A synergistic effect may also be observed between UV and thermal curing, surface curing, and bulk curing, thereby allowing for design of cure on demand compositions in a wide range of applications including not only in aircraft sealant, automotive sealant, electronic sealant and construction sealants, but also in industrial coatings and adhesives applications.

[0082] The sealant may be described as the polymerization product of the polysulfide and the isocyanate reacted in the presence of the catalyst. This typically forms a thio-urethane. Alternatively, the sealant may include, consist essentially of, or consist of, such a polymerization product. The terminology "consist essentially of describes embodiments that are free of polymers or co-polymers, of any known in the art, that are not the sealant itself, i.e., the polymerization product of the polysulfide and isocyanate reacted in the presence of the catalyst.

[0083] In various embodiments, the composition cures to have a viscosity of greater than 1,000, 1 ,500, 2,000, 2,500, or 3,000 cps in 45, 40, 35, 30, 25, 20, 15, 10, or 5 minutes. Typically, a maximum viscosity in 15, 10, or 5 minutes is greater than 1000 cps as measured using a viscometer such as a Brookfield DV-II + Pro with an appropriate spindle such as a #RV7 spindle. The maximum viscosities in these times may be 10,000, 50,000, 100,000, 500,000, 1,000,000, 1,500,000, etc. up to about 350,000,000, cps, measured in the same way. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0084] In various embodiments, the composition cures to a tack-free time of from 0.05 to 5 minutes after the start of cure according to DIN 65262-1. In other embodiments, the composition cures to a tack-free time of less than 120, 115, 110, 105, 100, 96, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10,or 5, minutes, after the start of cure according to DIN 65262-1. In other embodiments, the sealant has a complete curing time or the time until reaching a Shore hardness of 30, determined according to ISO 7619 or ASTM D2240, from 1 to 960 min, of from 5 to 300 min, of from 10 to 60 min. In additional embodiments, one or more portions of the sealant composition, e.g. the first and second components, may have a density, determined according to ISO 2781, of from 0.9 to 1.6 g/cm³ or from 1.2 to 1.5 g/cm³. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0085] In other embodiments, the sealant has a Shore A hardness, determined according to ISO 7619 and measured 2 weeks after cure in storage in air at 23 °C. and 50% relative atmospheric humidity, of from 20 to 80, of from 30 to 60, or of from 40 to 55. In additional embodiments, the sealant has a Shore A hardness of at least 10 within 30 to 180 minutes of curing. In further embodiments, the sealant has an elongation at break, determined according to ISO 37 and measured 2 weeks after cure during storage in air at 23 °C and 50% relative atmospheric humidity, of from 100 to 1000%, of from 200% to 800% or from 300% to 600%. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0086] In other embodiments, the sealant has an elongation, determined according to ISO 37 and measured after 168 hours in storage in a fuel at 60°C, using the jet Al type of fuel, is of from 100 to 800%, of from 200 to 600% or of from 300 to 500%. In other embodiments, the sealant has an elongation at break of the sealants according to the invention, determined according to ISO 37 and measured after 300 hours in storage in fuel at 100°C, using the jet Al type of fuel is preferably of from 100 to 700%, especially preferably of from 200 to 600% or 400 to 500%. In even further embodiments, the sealant has an elongation at break, determined according to ISO 37 and measured after 1000 hours in storage in water at 35°C, of from 100 to 700%, e.g. from 200 to 500% or 250 to 350%. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0087] In other embodiments, the sealant has a peel resistance on aluminum alloy 2024 T3, determined according to DIN 65262-1, of from 60 to 350 N/25 mm, e.g. from 100 to 250 N/25 mm or 160 to 200 N/25 mm. Alternatively, the sealant has a peel resistance on enamels, such as, for example, on base enamels including solvent such as, for example, epoxy base enamel 37035 A from Akzo Nobel Aerospace Coatings, on water-based base enamels such as, for example, those based on epoxy such as Seevenax 313-01 and Seevenax 313-02 from Mankiewicz, on cover enamels such as, for example, water-based top coats based on epoxies such as Seevenax 313-01 from Mankiewicz, on finish F 70-A from Mapaero and/or on solvent-containing top coats based on polyurethanes such as Aerodur 21-100 from Akzo Nobel and Alexit 406-22 from Mankiewicz, determined according to DIN 65262-1, of from 50 to 350 N/25 mm, e.g. from 10 to 300 N/25 mm or from 170 to 210 N/25 mm. In various embodiments, the peel resistance is determined on substrates of aluminum or aluminum alloys, of titanium or titanium alloys, of stainless steels, of composite materials such as, for example, carbon fiber-reinforced plastic CFP and/or on enamel substrates that have been enameled, for example, with at least one solvent-containing or water-based base coat and/or top coat, in particular based on epoxy, polyester or polyurethane enamel. In various non- limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0088] In additional embodiments, the sealant has a tensile strength, determined according to ISO 37 and measured after 2 weeks after UV irradiation with storage in air at 23 °C. and 50% relative atmospheric humidity, of from 0.5 to 3.5 MPa, e.g. from 1 to 3 MPa or 1.8 to 2.7 MPa. In other embodiments, the sealant has a tensile strength, determined according to ISO 37 and measured after 168 hours at 60°C in storage in fuel of jet Al type, is of from 0.5 to 3 MPa, e.g. of from 1 to 2.5 or 1.5 to 2 MPa. In further embodiments, the sealant has a tensile strength, determined according to ISO 37 and measured after 300 hours at 100°C. in storage in fuel of jet Al type, of from 0.5 to 3 MPa, e.g. from 1 to 2 or 0.8 to 1.1 MPa. In further embodiments, the sealant has a tensile strength, determined according to ISO 37 and measured after 1000 hours at 35°C in storage in water, of from 0.5 to 3 MPa, e.g. of from 1 to

2 MPa or 1.5 to 1.7 MPa. In various non- limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

[0089] In still other embodiments, the sealant exhibits no cracks or other defects that occur in determination of low temperature flexibility due to bending at an angle of 30 degrees at a temperature of -55°C, a tensile strength of from 0.5 to 2.8 MPa after 168 hours of storage in a fuel at a temperature of 60°C, after 300 hours of storage in a fuel at a temperature of 100°C, and after 1000 hours of storage in water at a temperature of 35°C, an elongation at break of from 100 to 800% after 168 hours of storage in fuel at a temperature of 60°C, after 300 hours of storage in a fuel at a temperature of 100°C, and after 1000 hours of storage in water at a temperature of 35°C and/or a density of from 1.00 to 1.45 g/cm³. In still other embodiments, the sealant as the following properties after complete curing: a tensile strength of from 0.5 to

3 MPa, an elongation at break of from 100 to 900% and/or a peel resistance of from 50 to 300 N/25 mm. In various non-limiting embodiments, all values and ranges of values between the aforementioned values are hereby expressly contemplated.

Article:

[0090] This disclosure also provides an article that includes a substrate and the composition and/or (cured or partially cured) sealant disposed thereon. The article may be one used in the aviation industry, but may also be used wherever a rapid and complete curing and especially a very rapid surface curing with a relatively long sealant processing time are necessary and/or advantageous. For example, the article may be a tank or area to be sealed. In various embodiments, the composition and/or sealant may be used for plastering as in gas stations and chemical installations, for example, for connecting structural elements placed on top of one another such as sheet metal, films and other substrates, for filling cavities and intermediate spaces, for coating metallic materials in particular and composites such as, for example, carbon fiber reinforced or glass fiber reinforced plastics, for aerodynamic smoothing and compaction as well as for preventing corrosion in locations where the anticorrosion layers of the metallic elements have been damaged or removed, for example, in the area of boreholes. A load-bearing function may also be fulfilled, for example, during shipping. In various embodiments, the article is used in the shipping industry such as, for example, in automotive engineering, in the construction of rail vehicles, in shipbuilding, in the airplane construction industry or in the spacecraft construction industry, in machine and equipment construction, in the building industry or for the production of furniture. In one embodiment, the article is an aircraft fuel tank. In another embodiment, the article is further defined as a construction article, aircraft/aerospace article, motor or rail vehicle, ship, machine, glass insulation, and/or furniture. In still another embodiment, the article is further defined as glass insulation.

Methods:

[0091] This disclosure also provides a method of forming the curable sealant composition wherein the method includes the steps of providing the polysulfide, the isocyanate component, and the catalyst and combining the polysulfide, the isocyanate component, and the catalyst to form the curable composition.

[0092] This disclosure further provides a method of forming the cured sealant wherein the method includes the steps of providing the polysulfide, the isocyanate component, and the catalyst and combining the polysulfide, the isocyanate component, and the catalyst such that the polysulfide polymerizes with the isocyanate component in the presence of the catalyst to form the cured sealant.

[0093] Even further, this disclosure provides a method of forming the article wherein the method includes the steps of providing the polysulfide, the isocyanate component, and the catalyst and applying the polysulfide, the isocyanate component, and the catalyst onto the substrate such that the polysulfide polymerizes with the isocyanate component in the presence of the catalyst and forms the cured sealant disposed on the substrate.

[0094] This method also provides a method of cure-on-demand triggered by UV irradiation wherein one or more catalysts are used to adjust processing time and cure time; surface cure time and bulk cure time. In various embodiments, the sealant is triggered by UV irradiation. Moreover, a developed sealant may be capable of curing in darkness with a time lag and also capable of continuing to cure after a UV source is removed. This disclosure also provides a method to achieve cure-on-demand for thicknesses significantly larger that traditional cure- on-demand systems. For example, the system and method of this disclosure could cure up to more than 10mm of thickness.

[0095] In the aforementioned methods, each step of providing may be any known in the art. Similarly, any step of combining may be any known in the art such that any one or more of the aforementioned components may be combined in any order and as a whole or in parts. Moreover, the step of applying may be further defined as dipping, pouring, spraying, brushing, or any other method of application known in the art.

[0096] Any one or more of the aforementioned additives may be utilized and combined with any one or more of the aforementioned components in any one or more steps of the method. Similarly, heat and/or UV light may also be used as part of the method. For example, one or more components of the method maybe heated to a temperature of from 10 to 100, 20 to 90, or 20 to 80, °C, to cure the components. Similarly, UV light at wavelengths of from 310 to 380, from 280 to 310, or from 270 to 310, nm, may be used to cure the components.

[0097] In various embodiments, the article, the curable composition, and/or the composition after curing have one or more of the following:

an Elongation Before Jet Fuel Test of from 150 to 1500, 200 to 1450, 250 to 1400, 300 to 1350, 350 to 1300, 400 to 1250, 450 to 1200, 500 to 1150, 550 to 1100, 600 to 1050, 650 to 1000, 700 to 950, 750 to 900, 800 to 850, 100 to 500, 150 to 450, 200 to 400, 250 to 350, 300 to 350, 160 to 290, 170 to 300, 165 to 295, 170 to 290, 175 to 285, 180 to 280, 185 to 275, 190 to 270, 195 to 265, 200 to 260, 205 to 255, 210 to 250, 215 to 245, 220 to 240, 225 to 235, or 225 to 230, % as determined using ASTM D 412. In other embodiments, the curable composition, and/or the composition after curing has an Elongation Before Jet Fuel Test of from 200 to 500, 250 to 450, 300 to 400, or 350 to 400, % as determined using ASTM D 412.

an Elongation After Jet Fuel Test of from 150 to 1500, 200 to 1450, 250 to 1400, 300 to 1350, 350 to 1300, 400 to 1250, 450 to 1200, 500 to 1150, 550 to 1100, 600 to 1050, 650 to 1000, 700 to 950, 750 to 900, 800 to 850, 100 to 500, 150 to 450, 200 to 400, 250 to 350, 300 to 350, 160 to 290, 170 to 300, 165 to 295, 170 to 290, 175 to 285, 180 to 280, 185 to 275, 190 to 270, 195 to 265, 200 to 260, 205 to 255, 210 to 250, 215 to 245, 220 to 240, 225 to 235, or 225 to 230, % as determined using ASTM D 412. In other embodiments, the curable composition, and/or the composition after curing has an Elongation After Jet Fuel Test of from 300 to 500, 350 to 450, or 400 to 450, % as determined using ASTM D 412. a Strength Before Jet Fuel Test of from 150 to 1500, 200 to 1450, 250 to 1400, 300 to 1350, 350 to 1300, 400 to 1250, 450 to 1200, 500 to 1150, 550 to 1100, 600 to 1050, 650 to 1000, 700 to 950, 750 to 900, 800 to 850, 100 to 500, 150 to 450, 200 to 400, 250 to 350, 300 to 350, 160 to 290, 170 to 300, 165 to 295, 170 to 290, 175 to 285, 180 to 280, 185 to 275, 190 to 270, 195 to 265, 200 to 260, 205 to 255, 210 to 250, 215 to 245, 220 to 240, 225 to 235, 225 to 230, 200 to 400, 250 to 350, 300 to 350, 250 to 300, 255 to 295, 260 to 290, 265 to 285, 270 to 280, or 275 to 280, psi as determined using ASTM D 412. In other embodiments, the curable composition, and/or the composition after curing has a Strength Before Jet Fuel Test of from 200 to 1000, 250 to 950, 300 to 900, 350 to 850, 400 to 800, 450 to 750, 500 to 700, 550 to 650, or 600 to 650, % as determined using ASTM D 412.

a Strength After Jet Fuel Test of 150 to 1500, 200 to 1450, 250 to 1400, 300 to 1350, 350 to 1300, 400 to 1250, 450 to 1200, 500 to 1150, 550 to 1100, 600 to 1050, 650 to 1000, 700 to 950, 750 to 900, 800 to 850, 100 to 500, 150 to 450, 200 to 400, 250 to 350, 300 to 350, 160 to 290, 170 to 300, 165 to 295, 170 to 290, 175 to 285, 180 to 280, 185 to 275, 190 to 270, 195 to 265, 200 to 260, 205 to 255, 210 to 250, 215 to 245, 220 to 240, 225 to 235, 225 to 230, 200 to 400, 250 to 350, 300 to 350, 250 to 300, 255 to 295, 260 to 290, 265 to 285, 270 to 280, or 275 to 280, psi as determined using ASTM D 412. In other embodiments, the curable composition, and/or the composition after curing has a Strength After Jet Fuel Test of from 150 to 800, 200 to 750, 250 to 700, 300 to 650, 350 to 600, 400 to 550, or 450 to 500, % as determined using ASTM D 412. In addition all values and range of values between and including all those described above are hereby expressly contemplated herein in various non-limiting embodiments.

[0098] All combinations of the aforementioned embodiments throughout the entire disclosure are hereby expressly contemplated in one or more non-limiting embodiments even if such a disclosure is not described verbatim in a single paragraph or section above. In other words, an expressly contemplated embodiment may include any one or more elements described above selected and combined from any portion of the disclosure.

[0099] One or more of the values described above may vary by ± 5%, ± 10%, ± 15%, ± 20%, ± 25%, etc. so long as the variance remains within the scope of the disclosure. Unexpected results may be obtained from each member of a Markush group independent from all other members. Each member may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims. The subject matter of all combinations of independent and dependent claims, both singly and multiply dependent, is herein expressly contemplated. The disclosure is illustrative including words of description rather than of limitation. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described herein.

[00100] In various non-limiting embodiments, one or more elements, components, compounds, method steps, etc. from one or both of concurrently filed provisional applications (BASF Docket Numbers: 160061 and 160727) can be utilized. Each of these provisional applications is expressly incorporated herein by reference in its entirety relative to these non- limiting embodiments.

[00101] It is also to be understood that any ranges and subranges relied upon in describing various embodiments of the present disclosure independently and collectively fall within the scope of the appended claims, and are understood to describe and contemplate all ranges including whole and/or fractional values therein, even if such values are not expressly written herein. One of skill in the art readily recognizes that the enumerated ranges and subranges sufficiently describe and enable various embodiments of the present disclosure, and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so on. As just one example, a range "of from 0.1 to 0.9" may be further delineated into a lower third, i.e. from 0.1 to 0.3, a middle third, i.e. from 0.4 to 0.6, and an upper third, i.e. from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims, and may be relied upon individually and/or collectively and provide adequate support for specific embodiments within the scope of the appended claims. In addition, with respect to the language which defines or modifies a range, such as "at least," "greater than," "less than," "no more than," and the like, it is to be understood that such language includes subranges and/or an upper or lower limit. As another example, a range of "at least 10" inherently includes a subrange of from at least 10 to 35, a subrange of from at least 10 to 25, a subrange of from 25 to 35, and so on, and each subrange may be relied upon individually and/or collectively and provides adequate support for specific embodiments within the scope of the appended claims. Finally, an individual number within a disclosed range may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims. For example, a range "of from 1 to 9" includes various individual integers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1, which may be relied upon and provide adequate support for specific embodiments within the scope of the appended claims.

Claims

CLAIMS What is claimed is:

1. A curable sealant composition comprising:

A. a polysulfide having an -SH group;

B. an isocyanate component; and

C. a catalyst component comprising a first catalyst and an imidazolium catalyst, wherein said first catalyst has the structure:

wherein R¹ is in the 2, 3, 4, 5, or 6 position and R¹ is chosen from H, C¾, CH₂CH₃, COCH3, OCOCH3, COCH2CH3, OCOCH2CH3, OCH3, and OCH2CH3; and wherein R² is chosen from H, CH3, and CH2CH3

and wherein said imidazolium catalyst has the structure:

wherein each of R³ and R⁵ is independently an organic radical having 1 to 20 carbon atoms, each of R⁴, R⁶, and R⁷ is independently H or an organic radical having 1 to 20 carbon atoms, and A^" is an anion.

2. The curable sealant composition of claim 1 wherein R¹ is in the 4 position.

3. The curable sealant composition of claim 1 or 2 wherein R¹ and R² are both hydrogen atoms.

4. The curable sealant composition of claim 1 or 2 wherein R 1 and R 2 are both hydrogen atoms and wherein said catalyst component further comprises a second first catalyst wherein R¹ is OCOCH3 and R² is a hydrogen atom.

5. The curable sealant composition of claim 1 or 2 wherein R¹ is OCOCH3 and R' is a hydrogen atom.

6. The curable sealant composition of any one of claims 1-5 wherein R³ is ethyl, R⁴ is H; R⁵ is methyl; R⁶ is H; R⁷ is H, and A^" is benzoate.

7. The curable sealant composition of any one of claims 1-6 wherein said catalyst component is present in a total amount of from 0.001 to 5 parts by weight per 100 parts by weight of said curable composition.

8. The curable sealant composition of any one of claims 1-7 wherein said polysulfide has an -SH functionality of greater than or equal to 2.

9. The curable sealant composition of any one of claims 1-8 wherein said polysulfide has a weight average molecular weight of from 1,000 to 7,500 g/mol.

10. The curable sealant composition of any one of claims 1-7 wherein said polysulfide is further defined as comprising a plurality of blocks each having the formula - R³-S_x- wherein x is from 1 to 5 and R³ is an alkyl group having 2 to 16 carbon atoms or an alkyl group 16 carbon atoms that further comprises an ether-bond, and further having a terminal thiol group having the formula -R⁴-SH wherein R⁴ is an alkyl group having 2 to 16 carbon atoms or an alkyl group having 2 to 16 carbon atoms that further comprises an ether- bond.

11. The curable sealant composition of any one of claims 1-7 further comprising a second polysulfide wherein each of said polysulfide and said second polysulfide are independently comprise a plurality of blocks having the formula -R³-S_x- wherein x is from 1 to 5 and R³ is an alkyl group having 2 to 16 carbon atoms or an alkyl group 16 carbon atoms that further comprises an ether-bond, and further having a terminal thiol group having the formula -R⁴-SH wherein R⁴ is an alkyl group having 2 to 16 carbon atoms or an alkyl group having 2 to 16 carbon atoms that further comprises an ether-bond.

12. The curable sealant composition of any one of claims 1-7 wherein said polysulfide has the formula -R⁵-[-S-(CH₂)2-0-[-R⁶-0-]_m-(CH₂)2-S-R⁵-]_n-,

wherein each of R⁵ and R⁶ is independently a C₂-C6 n-alkylene group, a C3-C6 branched alkylene group, a C6-C₈ cycloalkylene group, a C6-C10 alkylcycloalkylene group, or -[(-CH₂-)p-X-]_q-(-CH₂-)_r, or -[(-CH₂-)p-X-]_q-(-CH₂-)_r- in which at least one CH₂ unit is substitute with a methyl group,

wherein m is a number from 0 to 10;

wherein n is a number from 1 to 60;

wherein p is a number from 2 to 6;

wherein q is a number from 1 to 5; and

wherein r is a number from 2 to 10.

13. The curable sealant composition of any one of claims 1-7 wherein said polysulfide has the formula: HS-(C2H4-0-CH2-0-C2H4-(S-S)2-8)x-C2H4-0-CH2-0-C₂H4-SH

wherein x is from 1 to 200.

14. The curable sealant composition of any one of claims 1-7 wherein said polysulfide has the formula:

H(S-C₂H4-0-CH2-0-C₂H4-S)_zH

wherein z is from 7 to 43.

15. The curable sealant composition of any one of claims 1-7 wherein said polysulfide has the formula: HS-(R-SS)_t-R-SH, wherein each R is independently a C2-C6 n- alkylene group, a C3-C6 branched alkylene group, a C6-C₈ cycloalkylene group, or a C6-C10 alkylcycloalkylene group and wherein t is from 5 to 40.

16. The curable sealant composition of any one of claims 1-7 wherein said polysulfide has the formula: HS-(R-SS)_q-CH₂CH((SS-R)v-SH)-CH₂-(SS-R)_rSH, wherein each R is independently a C2-C6 n-alkylene group, a C3-C6 branched alkylene group, a C6-C₈ cycloalkylene group, or a C6-C10 alkylcycloalkylene group, wherein q+v+r is from 5 to 40.

17. The curable sealant composition of any one of claims 1-7 wherein said polysulfide has the formula:

HS-R-(0-CH2-CH2-S-CH2-CH2-0-CH-CH2-S-CH2-0-CH2-CH2-S-CH2-CH₂-)-R-SH wherein each R is independently a C2-C6 n-alkylene group, a C3-C6 branched alkylene group, a C6-C₈ cycloalkylene group, or a C6-C10 alkylcycloalkylene group.

18. The curable sealant composition of any one of claims 1-17 wherein said isocyanate component is a prepolymer of a polysulfide and an isocyanate.

19. The curable sealant composition of any one of claims 1-17 wherein said isocyanate component is chosen from methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and combinations thereof.

20. The curable sealant composition of any one of claims 1-19 further comprising a UV photosensitizer.

21. The curable sealant composition of any one of claims 1-20 wherein said polysulfide and said isocyanate component are present in the composition in a weight ratio of from 16:1 to 2:1.

22. The curable sealant composition of any one of claims 1-21 that has:

an Elongation Before Jet Fuel Test of 200 to 500% as determined using ASTM D 412;

an Elongation After Jet Fuel Test of 300 to 500% as determined using ASTM D 412; a Strength Before Jet Fuel Test of 200 to 1000 psi as determined using ASTM D 412; and

a Strength After Jet Fuel Test of 150 to 800 psi as determined using ASTM D 412.

23. A curable sealant composition comprising:

a first portion comprising a polysulfide having an -SH group, and a catalyst component comprising a first catalyst and an imidazolium catalyst, wherein said first catalyst has the structure:

wherein R is in the 2, 3, 4, 5, or 6 position and R is chosen from H, C¾,

CH₂CH₃, COCH3, OCOCH3, COCH2CH3, OCOCH2CH3, OCH3, and OCH2CH3; and wherein R² is chosen from H, CH3, and CH2CH3

and wherein said imidazolium catalyst has the structure:

wherein each of R³ and R⁵ is independently an organic radical having 1 to 20 carbon atoms, each of R⁴, R⁶ and R⁷ is independently H or an organic radical having 1 to 20 carbon atoms, and A^" is an anion; and

a second portion comprising an isocyanate component,

wherein said polysulfide is present in an amount of from 50 to 80 weight percent based on a total weight of said first portion;

wherein said catalyst component is present in an amount of from 0.01 to 5 weight percent based on a total weight of said first portion; and

wherein said isocyanate component is present in an amount of from 80 to 100 weight percent based on a total weight percent of said second portion.

24. The curable sealant composition of claim 23 wherein said first portion further comprises a UV photosensitizer present in an amount of from 0.1 to 5 weight percent based on a total weight percent of said first portion.

25. The curable sealant composition of claim 23 or 24 wherein said isocyanate component is a prepolymer of a polysulfide and an isocyanate.

26. A cured sealant that is the polymerization product of a polysulfide having an - SH group and an isocyanate reacted in the presence of a catalyst component comprising a first catalyst and an imidazolium catalyst, wherein said first catalyst has the structure:

wherein R is in the 2, 3, 4, 5, or 6 position and R is chosen from H, C¾,

and wherein said imidazolium catalyst has the structure:

wherein each of R 3 and R 5 is independently an organic radical having 1 to 20 carbon atoms, each of R⁴, R⁶, and R⁷ is independently H or an organic radical having

1 to 20 carbon atoms, and A^" is an anion.

27. A method of forming a curable sealant composition comprising a polysulfide having an -SH group, an isocyanate component, and a catalyst component, said method comprising the steps of:

providing the polysulfide, the catalyst, and the metal oxide catalyst; and

combining the polysulfide, the isocyanate component, and the catalyst component to form the curable sealant composition,

wherein the catalyst component comprises a first catalyst and an imidazolium catalyst, wherein the first catalyst has the structure:

and wherein the imidazolium catalyst has the structure:

28. A method of forming a cured sealant comprising the polymerization product of a polysulfide having an -SH group and an isocyanate component reacted in the presence of a catalyst component, said method comprising the steps of:

providing the polysulfide, the isocyanate component, and the catalyst component; and combining the polysulfide, the isocyanate component, and the catalyst component such that the polysulfide and the isocyanate component polymerize in the presence of the catalyst component to form the cured sealant,

wherein R¹ is in the 2, 3, 4, 5, or 6 position and R¹ is chosen from H, C¾, CH2CH3, COCH3, OCOCH3, COCH2CH3, OCOCH2CH3, OCH3, and OCH2CH3; and wherein R² is chosen from H, CH3, and CH2CH3

and wherein the imidazolium catalyst has the structure:

1 to 20 carbon atoms, and A^" is an anion.

29. An article comprising a substrate and a cured sealant disposed thereon, wherein said cured sealant comprises the reaction product of a polysulfide having an -SH group and an isocyanate reacted in the presence of a catalyst component comprising a first catalyst and an imidazolium catalyst, wherei catalyst has the structure:

wherein R is in the 2, 3, 4, 5, or 6 position and R is chosen from H, CH3,

CH₂CH₃, COCH3, OCOCH3, COCH2CH3, OCOCH2CH3, OCH3, and OCH2CH3; and wherein R is chosen from H, CH3, and CH2CH3

and wherein said imidazolium catalyst has the structure:

wherein each of R 3 and R 5 is independently an organic radical having 1 to 20 carbon atoms, each of R⁴, R⁶, and R⁷ is independently H or an organic radical having 1 to 20 carbon atoms, and A^" is an anion.

30. The article of claim 29 that is further defined as an aircraft fuel tank.

31. The article of claim 29 that is further defined as a construction article, aircraft/aerospace article, motor or rail vehicle, ship, machine, glass insulation, and/or furniture.

32. The article of any one of claims 29-31 that has:

33. A method of forming an article comprising a substrate and a cured sealant disposed thereon, wherein the cured sealant comprises the reaction product of a polysulfide having an -SH group and an isocyanate reacted in the presence of a catalyst component comprising a first catalyst and an imidazolium catalyst, wherein the first catalyst has the structure:

wherein R is in the 2, 3, 4, 5, or 6 position and R is chosen from H, CH3,

and wherein the imidazolium catalyst has the structure:

1 to 20 carbon atoms, and A^" is an anion, said method comprising the steps of:

providing the polysulfide, the isocyanate, and the catalyst component; and applying the polysulfide, the isocyanate, and the catalyst component onto the substrate such that the polysulfide polymerizes with the isocyanate in the presence of the catalyst component and forms the cured sealant disposed on the substrate.