Compositions comprising magnesium oxide and a non-chrome corrosion inhibitor

Abstract

Disclosed herein are compositions comprising: a film-forming binder comprising a base comprising a film-forming resin comprising a sulfur-containing compound; magnesium oxide; and a second corrosion inhibitor in addition to the magnesium oxide. Also disclosed are sealants formed from any of the disclosed compositions.

Description

COMPOSITIONS COMPRISING MAGNESIUM OXIDEAND A NON-CHROME CORROSION INHIBITORCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U. S. Provisional Application No. 63 / 764,487, filed on February 27, 2025, entitled “COMPOSITIONS COMPRISING MAGNESIUM OXIDE AND A NON-CHROME CORROSION INHIBITOR” incorporated herein in its entirety.FIELD

[0002] The present disclosure is directed to compositions comprising magnesium oxide and a non-chrome corrosion inhibitor.BACKGROUND

[0003] Coating compositions comprising film-forming binders have been widely applied to, for example, appliances, automobiles, aircrafts, and the like. Such coatings may also comprise corrosion inhibitors that provide corrosion resistance.SUMMARY

[0004] Disclosed herein are compositions comprising: a film-forming binder comprising a base comprising a film-forming resin comprising a sulfur-containing compound; magnesium oxide; and a second corrosion inhibitor in addition to the magnesium oxide.

[0005] Also disclosed are sealants formed from any of the disclosed compositions.BRIEF DESCRIPTION OF THE FIGURES

[0006] FIG. 1 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for spayable polysulfide sealants of Example A containing magnesium oxide and metal oxide or mixed metal oxide.

[0007] FIG. 2 is a bar graph showing NSS Corrosion Rating on 7075-T6 substrate for sprayable polysulfide sealants of Example A containing magnesium oxide and metal oxide or mixed metal oxide.

[0008] FIG. 3 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for sprayable polysulfide sealants of Example A containing magnesium oxide and metal nitrate.

[0009] FIG. 4 is a bar graph showing NSS Corrosion Rating on 7075-T6 substrate for sprayable polysulfide sealants of Example A containing magnesium oxide and metal nitrate.

[0010] FIG. 5 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for sprayable polysulfide sealants of Example A containing magnesium oxide and organic nitrate.

[0011] FIG. 6 is a bar graph showing NSS Corrosion Rating on 7075-T6 substrate for sprayable polysulfide sealants of Example A containing magnesium oxide and organic nitrate.

[0012] FIG. 7 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for sprayable polysulfide sealants of Example A containing magnesium oxide and conjugated compound.

[0013] FIG. 8 is a bar graph showing NSS Corrosion Rating on 7075-T6 substrate for sprayable polysulfide sealants of Example A containing magnesium oxide and conjugated compound.

[0014] FIG. 9 is a bar graph showing filiform corrosion performance for sprayable polysulfide sealants of Example A containing magnesium oxide and a metal oxide or a mixed metal oxide.

[0015] FIG. 10 is a bar graph showing filiform corrosion performance for spray able polysulfide sealants of Example A containing magnesium oxide and a metal nitrate.

[0016] FIG. 11 is a bar graph showing filiform corrosion performance for sprayable polysulfide sealants of Example A containing magnesium oxide and an organic nitrate.

[0017] FIG. 12 is a bar graph showing filiform corrosion performance for sprayable polysulfide sealants of Example A containing magnesium oxide and a conjugated compound.

[0018] FIG. 13 is a bar graph showing swell under STD conditions of sprayable polysulfide sealants of Example A containing magnesium oxide and mixed metal oxide.

[0019] FIG. 14 is a bar graph showing swell at 60°C of sprayable polysulfide sealants of Example A containing magnesium oxide and mixed metal oxide.

[0020] FIG. 15 is a bar graph showing swell under STD conditions of sprayable polysulfide sealants of Example A containing magnesium oxide and a metal nitrate.

[0021] FIG. 16 is a bar graph showing swell at 60°C of sprayable polysulfide sealants of Example A containing magnesium oxide and a metal nitrate.

[0022] FIG. 17 is a bar graph showing swell under STD conditions of sprayable polysulfide sealants of Example A containing magnesium oxide and an organic nitrate.

[0023] FIG. 18 is a bar graph showing swell at 60°C of sprayable polysulfide sealants of Example A containing magnesium oxide and an organic nitrate.

[0024] FIG. 19 is a bar graph showing swell under STD conditions of sprayable polysulfide sealants of Example A containing magnesium oxide and a conjugated compound.

[0025] FIG. 20 is a bar graph showing swell at 60°C of sprayable polysulfide sealants of Example A containing magnesium oxide and a conjugated compound.

[0026] FIG. 21 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for polysulfide sealants of Example B containing magnesium oxide and a second corrosion inhibitor in addition to the magnesium oxide.

[0027] FIG. 22 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for polythioether sealants of Example C containing magnesium oxide and a metal oxide or a mixed metal oxide.

[0028] FIG. 23 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for polythioether sealants of Example C containing magnesium oxide and a metal nitrate.

[0029] FIG. 24 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for polythioether sealants of Example C containing magnesium oxide and an organic nitrate.

[0030] FIG. 25 is a bar graph showing NSS Corrosion Rating on 2024-T3 substrate for polythioether sealants of Example C containing magnesium oxide and a conjugated compound.DETAILED DESCRIPTION

[0031] The present disclosure is directed to a composition comprising, or consisting essentially of, or consisting of: a base comprising film-forming binder comprising a filmforming resin comprising a sulfur-containing compound; magnesium oxide; and a second corrosion inhibitor in addition to the magnesium oxide.Film-Forming Binder

[0032] A “film-forming binder” is one that, upon hardening and / or curing, can form a continuous film on a surface. The film-forming binder may comprise a film-forming resin such as an organic resin. The film-forming binder may further comprise a curing agent reactive with the film-forming resin.

[0033] The film-forming resin comprises, or consists essentially of, or consists of, a sulfur-containing compound, such as a polythiol, a polythioether, and / or an elastomer complex.

[0034] Generally, these compounds, which need not be polymeric, can be made by any method known to those skilled in the art. The film-forming resin may comprise a functional group, such as a thiol group. The functional group on the film-forming resin may be selected so as to be reactive with a functional group on the curing agent or to be self-crosslinking.

[0035] The sulfur-containing compound may comprise a thiol-terminated compound. The thiol-terminated compound may be a monomer, a polymer, and / or an oligomer. Suitable thiol-terminated compounds are disclosed in U. S. Patent No. 7,858,703B2, 3:27 to 11:54, incorporated herein by reference. The thiol-terminated compound may comprise a liquid.

[0036] The thiol-terminated compound of the present disclosure may have the structure of Formula (I):HS-R’-SH (I)wherein R1is selected from C2-6 alkanediyl, Ce-8 cycloalkanediyl, C6-10 alkanecycloalkanediyl, C5-8 heterocycloalkanediyl, substituted C2-6 alkanediyl, substituted C6-8 cycloalkanediyl, substituted C6-10 alkanecycloalkanediyl, substituted C5-8 heterocycloalkanediyl and — [(CHR3)P— X]q— (CHR3)r—; where, each R3is selected from hydrogen and methyl; each X is independently selected from O, S, S — S, NH, and N(—CH₃); 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. In examples, each p can independently be 2, 3, 4, 5, and 6. In examples, each p can be the same and can be 2, 3, 4, 5, or 6.

[0037] Further useful dithiols include one or more heteroatom substituents in the carbon backbone, that is, dithiols in which X includes a heteroatom such as O, S, S-S or another bivalent heteroatom radical; a secondary or tertiary amine group, i.e., — NR6—, where R6is hydrogen or methyl; or another substituted trivalent heteroatom. In an example, X is O or S, and thus R1is — [( — CH2 — )P— O — ]q— ( — CH2 — )i — or — [( — CH2 — )P— S — ]q— ( — CH2 — )t —. In examples, p and r may be equal, and in an example, both have the value of 2.

[0038] Useful polythiols include but are not limited to dithiols such as 1,2-ethanedithiol, 1.2-propanedithiol, 1,3-propanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1.3-pentanedithiol, 1,5-pentanedi thiol, 1,6-hexanedithiol, l,3-dimercapto-3-methylbutane, dipentenedimercaptan, ethylcyclohexyldithiol (ECHDT), dimercaptodiethylsulfide, methylsubstituted dimercaptodiethylsulfide, dimethyl-substituted dimercaptodiethylsulfide, dimercaptodioxaoctane, l,5-dimercapto-3-oxapentane and mixtures thereof. The polythiol material can have one or more pendant groups selected from lower alkyl groups, lower alkoxy groups and hydroxyl groups. Suitable alkyl pendant groups include Ci-Ce linear alkyl, C3-Ce branched alkyl, cyclopentyl, and cyclohexyl.

[0039] Useful dithiols include dimercaptodiethylsulfide (DMDS) (p=2, r=2, q=l, X=S); dimercaptodioxaoctane (DMDO) (p=2, q=2, r=2, X=0); and l,5-dimercapto-3-oxapentane (p=2,r=2, q=l, X=0). It is also possible to use dithiols that include both heteroatom substituents in the carbon backbone and pendant alkyl groups, such as methyl groups. Such compounds include methyl-substituted DMDS, such as HS— CH2CH(CH3)— S— CH2CH2— SH, HS— CH(CH3)CH2— S — CH2CH2 — SH and dimethyl substituted DMDS such as HS — CH2CH(CH3)— S— CH(CH3)CH2— SH and HS— CH(CH3)CH2— S— CH2CH(CH3)— SH.

[0040] Two or more different polythiols can be used if desired in the compositions of the present disclosure.

[0041] A thiol- terminated compound useful in the compositions of the present disclosure may have the structure of formula (II):HS— R1— [— S— (CH2)P— O— (— R2— O— )m— (CH2)q— S— R1— ]n— SH (II) wherein R1denotes a C2-10 n-alkylene, C2-6 branched alkylene, Ce-8 cycloalkylene or Ce- 10 alkylcycloalkylene group, heterocyclic, — [( — CH2)P— X]q— ( — CH2)r; or — [( — CH2)P— X]q— ( — CH2)t — in which at least one — CH2 — unit is substituted with a methyl group; R2denotes a C210 n-alkylene, C2-6 branched alkylene, Ce-8 cycloalkylene or Ce-14 alkylcycloalkylene group, heterocyclic, — [( — CH2)P— X]q— ( — CH2; X denotes one selected from the group consisting of O, S, S-S and — NR6—; R6denotes H or methyl; m is an independently selected rational number from 1 to 50; and n is an independently selected integer from 1 to 60; p is an independently selected integer ranging from 2 to 6; q is an independently selected integer ranging from 1 to 5; and r is an independently selected integer from 2 to 10. In an example of the foregoing polymer, R1is C2-C6 alkyl and R2is C2-C6 alkyl.

[0042] Polyfunctional thiol-terminated polymers according to the present disclosure may have the formula:B—{R8CH2CH2—O—(R2—O)mCH2CH2—S—R1—[—S—CH2CH2—O—(R2—O)m—CH2— S— R¹]n—SH}z or B—{R⁸—S—R¹—[—S—CH₂CH₂—O—(R²—O)m—CH₂—S—R¹]n—SH}z wherein B denotes a z- valent residue of a polyfunctionalizing agent. R1, R2, n and m denote structures and values discussed above with reference to Formula II, R8denotes a residue of a terminal vinyl group or mercapto group, and z is an integer from 3 to 6.

[0043] Other suitable thiol-terminated monomers for use in the compositions of the present disclosure include, for example, mercapto-propionates, mercapto-acetates, mercaptoacrylates. and combinations of any of the foregoing.

[0044] Examples of suitable mercapto-propionates for use in the compositions of the present disclosure include pentaerythritol tetra(3-mercapto-propionate) (PETMP), trimethylolpropane tri(3-mercaptopropionate) (TMPMP), glycol di(3-mercaptopropionate) (GDMP). tris[2-(3-mercapto-propionyloxy)ethyl]isocyanurate (TEMPIC), di-pentaerythritol hexa(3-mercaptopropionate) (di-PETMP), tri(3-mercaptopropionate) pentaerythritol, triethylolethane tri-(3-mercaptopropionate), and combinations of any of the foregoing.

[0045] Examples of suitable polymeric thiols for use in the compositions of the present disclosure include ethoxylated trimethylolpropane tri(3-mercaptopropionate), polycaprolactone tetra-3-mercaptopropionate, and combinations thereof.

[0046] Examples of suitable mercapto-acetates for use in the compositions of the present disclosure include pentaerythritol tetramercaptoacetate (PRTMA). trimethylolpropane trimercaptoacetate (TMPMA), glycol dimercaptoacetate (GDMA), ethyleneglycol dimercaptoacetate, di-trimethylolpropane tetramercaptoacetate, and combinations of any of the foregoing.

[0047] Examples of suitable mercapto-acrylates for use in the compositions of the present disclosure include pentaerythritol tetra-acrylate, tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate, 2,3-di(2-mercaptoethylthio)- 1 -propane-thiol, dimercaptodiethylsulfide (2,2'-thiodiethanethiol), dimercaptodioxaoctane (2,2'-(ethylenedioxy)diethanethiol. l,8-dimercapto-3,6-dioxaoctane, and combinations of any of the foregoing.

[0048] Suitable thiol-terminated monomers for use in compositions of the present disclosure are commercially available, for example, from Bruno Bock Thiochemicals under the Thiocure® tradename. Suitable thiol-terminated polymers for use in compositions of the present disclosure are commercially available, for example, from Toray Industries, Inc. under the Thiokol® LP tradename or from Nouryon under the Thioplast® tradename.

[0049] Other suitable thiol-terminated compounds useful in the present disclosure include those which are commercially available under the trade name Thiokol polysulfides (commercially available from Toray Chemical). Such polysulfide polymers are disclosed in U. S.Patent No. 2,466,963. Other suitable thiol-terminated compounds useful in the present disclosure include Thioplasts (commercially available from AkzoNobel).

[0050] The thiol-terminated compound may have a weight average molecular weight (Mw) of at least 80 g / mol, such as at least 100 g / mol, such as at least 150 g / mol, and may have a number average molecular weight of no more than 40,000 g / mol, such as no more than 30,000 g / mol, such as no more than 20,000 g / mol. The thiol-terminated compound may have a weight average molecular weight of 80 g / mol to 40,000 g / mol, such as 100 g / mol to 30,000 g / mol, such as 150 g / mol to 20,000 g / mol. As used herein, the term “weight average molecular weight” or “(Mw)” means the weight average molecular weight (Mw) as determined by gel permeation chromatography (GPC) using polystyrene standards for calibration. The GPC determination can be performed using a Waters 2695 separation module with a Waters 410 differential refractometer (RI detector), linear polystyrene standards having molecular weights of from 580 Da to 365,000 Da, tetrahydrofuran (THF) as the eluent at a flow rate of 0.5 mL / min, and an Agilent PLgel Mixed-C column (300 x 7.5 mm, 5 μm) for separation.

[0051] The sulfur-containing compound may comprise a polythioether. As used herein, the term “polythioether” refers to compounds comprising at least two thioether linkages, that is “ — C — S — C — ” linkages. Suitable thiol-terminated polythioethers and methods for their production include, for example, those disclosed in U. S. Pat. No. 4,366,307 at col. 3, line 7 to col. 9, line 51 and U. S. Pat. No. 6,172,179 at col. 5. line 42 to col. 12, line 7, the cited portions of which being incorporated by reference herein. The thiol-terminated polythioether may comprise a polythioether that includes a structure having the Structure (III):— R1— [— S— (CH2)2— O— [— R2— O— ]m— (CH2)2—S—R1— ]n— (III)wherein: (1) each R1independently denotes a C2en-alkylene, C26 branched alkylene, G, 8 cycloalkylene or Ce-io alkylcycloalkylene group, — [( — CH2— )p— X — ]q— ( — CH2— )t—, or — [( — CH2— )p— X — ]q— ( — CH2— )x— in which at least one — CH2— unit is substituted with a methyl group, wherein (i) each X is independently selected from O, S and — NR6—, wherein R6denotes H or methyl; (ii) p is an integer having a value ranging from 2 to 6; (iii) q is an integer having a value ranging from 0 to 5; and (iv) r is an integer having a value ranging from 2 to 10; (2) each R2independently denotes a C2-6 n-alkylene, C2-6 branched alkylene, C6-8 cycloalkylene or C6-10 alkylcycloalkylene group, or — [( — CH2— )p— X — ]q— ( — CH2— )t—, wherein (i) each X is independently selected from O, S and — NR6—, wherein R6denotes H or methyl; (ii) p is aninteger having a value ranging from 2 to 6; (iii) q is an integer having a value ranging from 0 to 5; and (iv) r is an integer having a value ranging from 2 to 10; (3) m is a rational number from 0 to 10; and (4) n is an integer having a value ranging from 1 to 60. Such polythioethers and methods for their production are described in U. S. Pat. No. 6,172,179 within the portion thereof incorporated herein by reference above.

[0052] The thiol-terminated polythioether may have a structure according to Structure (IV):HS— R1— [— S— (CH2)2— O— [— R2— O— ]m— (CH2)2— S— R1— ]n— SH (IV)in which R1, R2, m and n are as described above with respect to formula (III).

[0053] The thiol-terminated polythioether may be polyfunctionalized. The thiol-terminated polythioether may have a structure according to formula (V):B-(A-[R3]y— SH)Z(V)wherein: (1) A denotes a structure according to formula (I); (2) y is 0 or 1; (3) R3denotes a single bond when y=0 and — S — (CH2)2— [ — O — R2— ]ra— O — when y=i; (4) z is an integer from 3 to 6; and (5) B denotes a z- valent residue of a polyfunctionalizing agent.

[0054] Suitable methods for making such polyfunctionalized polythioether polymers are disclosed in, for example, U. S. Pat. No. 6,172,179 at col. 7, line 48 to col. 12, line 7, the cited portion of which being incorporated herein by reference above.

[0055] The film-forming resin may further comprise an inorganic film-forming resin, such as a silicone resin.

[0056] When present, the curing agent may be selected so as to have reactivity with the film-forming resin. The curing agent may comprise a molecule or functional group that may react with a reactive group, such as a thiol group, on the film-forming resin to effectuate cure of the coating composition to form a coating.

[0057] Examples of suitable curing agents include a metal oxide and / or an organic peroxide. The metal oxide and / or the organic peroxide may polymerize the polythiols disclosed above to rubbery solids by oxidizing the thiol functional group of the thiol-terminated compound to form sulfur-sulfur bonds. For example, a mechanism of cure may comprise 2 -RSH + (O) -> RSSR + H2O.

[0058] Suitable examples of a metal oxide include zinc oxide, lead oxide, lead dioxide, lead peroxide, manganese dioxide, sodium dichromate, sodium perborate, sodium perboratemonohydrate, potassium permanganate, calcium dioxide, calcium peroxide, barium peroxide, lithium peroxide, zinc peroxide, zinc chromate, barium oxide, alkaline dichromate, or combinations thereof.

[0059] Suitable examples of an organic peroxide include cumene hydroperoxide, t-butyl hydroperoxide, or combinations thereof.

[0060] Other suitable curing agents include epoxy resins, for example, hydantoin diepoxide, diglycidyl ether of bisphenol- A, diglycidyl ether of bisphenol-F, Novolak type epoxides, and any of the epoxidized unsaturated and phenolic resins. Other useful curing agents include unsaturated compounds such as acrylic and methacrylic esters of commercially available polyols, unsaturated synthetic or naturally occurring resin compounds, TAC, and olefinic terminated derivatives of the compounds of the present invention.

[0061] The composition may comprise the film-forming binder in an amount of at least 80 percent by weight based on total weight of the composition, such as at least 85 percent by weight. The composition may comprise the film-forming binder in an amount of no more than 99.5 percent by weight based on total weight of the composition, such as no more than 90 percent by weight. The composition may comprise the film-forming binder in an amount of 80 percent by weight to 99.5 percent by weight based on total weight of the composition, such as 85 percent by weight to 90 percent by weight.Magnesium Oxide

[0062] The composition comprises magnesium oxide (MgO).

[0063] The MgO may comprise nano-sized MgO and / or micron-sized MgO. The particle size may be reported as average particle size by the manufacturer, or optionally, the number average particle size may be determined, for example, by visually examining a micrograph of a transmission electron microscopy (“TEM”) image, as described below.

[0064] The MgO may comprise a micron sized powder, or a dispersion thereof, having a number average particle size of at least 0.1 micron, such as at least 1 micron. The MgO may comprise a micron sized powder, or dispersion thereof, having a number average particle size of no more than 50 microns, such as no more than 30 microns. The MgO may comprise a micron sized powder, or dispersion thereof, having a number average particle size of 0.1 microns to 50 microns, such as 1 micron to 30 microns.

[0065] Alternatively, or in addition, the MgO may comprise a nano sized powder, or dispersions thereof. The MgO may comprise a nano sized powder having a number average particle size of at least 10 nm. The MgO may comprise a nano sized powder having a number average particle size of no more than 499 nm, such as no more than 100 nm. The MgO may comprise a nano sized powder having a number average particle size of 10 nm to 499 nm, such as 10 nm to 100 nm.

[0066] Number average particle size reported herein may be determined by visually examining a micrograph of a transmission electron microscopy (“TEM”) image, measuring the diameter of the particles in the image, and calculating the average primary particle size of the measured particles based on magnification of the TEM image. One of ordinary skill in the art will understand how to prepare such a TEM image and determine the primary particle size based on the magnification. The primary particle size of a particle refers to the smallest diameter sphere that will completely enclose the particle. As used herein, the term “primary particle size” refers to the size of an individual particle as opposed to an agglomeration of two or more individual particles.

[0067] Particle size as reported herein refers to the MgO particle size prior to incorporation into the coating composition. Various coating preparation methods may result in the MgO particles agglomerating, which could increase average particle size, or shearing or other action that can reduce average particle size. MgO particles are commercially available from a number of sources, such as NANO-MgO from U. S. Research Nanomaterials, Inc. (TX, USA), such as MAGLITE Y from The Hallstar Company (IL, USA), and the like.

[0068] The MgO may comprise ultrafine MgO particles. As used herein, the term “ultrafine” particles refers to particles that have a B. E. T. specific surface area of at least 0.05 square meters per gram (m2 / g), such as at least 0.1 m2 / g, such as at least 10 m2 / g, such as at least 30 m2 / g, such as no more than 500 m2 / g, such as no more than 200 m2 / g, such as no more than 100 m2 / g, such as no more than 70 m2 / g, such as 0.05 m2 / g to 500 m2 / g, such as 0.1 m2 / g to 200 m2 / g, such as 30 m2 / g to 200 m2 / g, such as 30 m2 / g to 70 m2 / g. As used herein, “B. E. T. specific surface area” refers to a specific surface area determined by nitrogen adsorption according to the ASTM D3663-78 standard based on the Brunauer- Emmett-Teller method described in the periodical “The Journal of the American Chemical Society,” 60, 309 (1938).

[0069] The MgO may comprise MgO particles having an equivalent spherical diameter of no more than 200 nm, such as no more than 100 nm, such as 5 nm to 50 nm. Equivalent spherical diameter may be measured using a particle size analyzer, such as a Beckman-Coulter unit, as a powder.

[0070] The shape (or morphology) of the MgO particles may vary. For example, the MgO particles may comprise particles having generally spherical morphologies and / or the MgO particles may be cubic, platy, polyhedric, or acicular (elongated or fibrous). The particles may be covered completely in a polymeric gel, not covered at all in a polymeric gel, or covered partially with a polymeric gel. Covered partially with a polymeric gel means that at least some portion of the particle has a polymeric gel deposited thereon, which, for example, may be covalently bonded to the particle or merely associated with the particle.

[0071] The MgO may comprise one or more different types of MgO particles. For example, the MgO may comprise MgO nanosized particles and MgO micron sized particles.

[0072] The MgO acts as a corrosion inhibitor that may provide at least some corrosion inhibition to the underlying substrate upon which the composition is applied.

[0073] The composition may comprise the magnesium oxide in an amount of at least 0.1 percent by weight based on total weight of the composition, such as at least 1 percent by weight. The composition may comprise the magnesium oxide in an amount of no more than 10 percent by weight based on total weight of the composition, such as no more than 8 percent by weight. The composition may comprise the magnesium oxide in an amount of 0.1 percent by weight to 10 percent by weight based on total weight of the composition, such as 1 percent by weight to 8 percent by weight.Additional Corrosion Inhibitors

[0074] The disclosed coating compositions comprise a second corrosion inhibitor in addition to the MgO.

[0075] The second corrosion inhibitor may comprise a metal oxide, a mixed metal oxide, a nitrate, and / or a conjugated compound. As used herein, a “conjugated compound” refers to a compound having two double bonds separated by a single bond, for example two carbon-carbon double bonds with a single carbon-carbon bond between them.

[0076] Suitable examples of nitrates that may be used as a second corrosion inhibitor include a metal nitrate and / or an organic nitrate.

[0077] The metal nitrate may be, for example, a rare earth metal nitrate, a lanthanide metal nitrate, and / or a transition metal nitrate. For example, the metal nitrate may comprise neodymium nitrate, yttrium nitrate, terbium nitrate, and / or praseodymium nitrate.

[0078] The composition may comprise the metal nitrate in an amount of at least 0.05 percent by weight based on total weight of the composition, such as at least 0.25 percent by weight. The composition may comprise the metal nitrate in an amount of no more than 3 percent by weight based on total weight of the composition, such as no more than 2 percent by weight. The composition may comprise the metal nitrate in an amount of 0.05 percent by weight to 3 percent by weight based on total weight of the composition, such as 0.25 percent by weight to 2 percent by weight.

[0079] The organic nitrate may comprise an azole. Suitable examples of azoles that may be used as a second corrosion inhibitor include a cyclic compound comprising 1 nitrogen atom, a cyclic compound comprising 2 or more nitrogen atoms, a cyclic compound comprising 1 nitrogen atom and 1 oxygen atom, and / or a cyclic compound comprising 1 nitrogen atom and 1 sulfur atom. For example, the second corrosion inhibitor may comprise a pyrrole, a pyrazole, an imidazole, a triazole, a tetrazole, a pentazole, an oxazole, an isoxazole, a thiazole, and / or an isothiazole. For example, the azole nitrate may be isoconazole nitrate and / or econazole nitrate.

[0080] The composition may comprise the organic nitrate in an amount of at least 0.05 percent by weight based on total weight of the composition, such as at least 0.25 percent by weight. The composition may comprise the organic nitrate in an amount of no more than 3 percent by weight based on total weight of the composition, such as no more than 2 percent by weight. The composition may comprise the organic nitrate in an amount of 0.05 percent by weight to 3 percent by weight based on total weight of the composition, such as 0.25 percent by weight to 2 percent by weight.

[0081] Suitable examples of metal oxides and mixed metal oxides that may be used as a second corrosion inhibitor include an alkali metal oxide, a lanthanide metal oxide, and / or a transition metal oxide. For example, the metal oxide and / or mixed metal oxide may be lithium, vanadium, praseodymium, terbium, yttrium, and / or neodymium. For example, the mixed metal oxide may be lithium vanadium oxide.

[0082] The composition may comprise the metal oxide and / or the mixed metal oxide in an amount of at least 0.1 percent by weight based on total weight of the composition, such as atleast 0.25 percent by weight, such as at least 0.4 percent by weight. The composition may comprise the metal oxide and / or the mixed metal oxide in an amount of no more than 10 percent by weight based on total weight of the composition, such as no more than 7 percent by weight, such as no more than 5 percent by weight. The composition may comprise the metal oxide and / or the mixed metal oxide in an amount of 0.1 percent by weight to 10 percent by weight based on total weight of the composition, such as 0.25 percent by weight to 7 percent by weight, such as 0.4 percent by weight to 5 percent by weight.

[0083] Suitable examples of conjugated compounds include methyl orange, xylenol orange, catechol violet, bromophenol blue, green and purple, eriochrome black T, methyl blue, celestine blue, hematoxylin, calmagite, and / or gallocyanine. Optionally, the conjugated compound may comprise an organic compound that is a metal ion indicator. Nonlimiting examples of conjugated compounds include those found in Table. Fluorescent conjugated compounds, which will emit light in certain conditions, can also be used. As used herein, “fluorescent” and like terms, when used with respect to the conjugated compounds, refer to compounds, molecules, pigments, and / or dyes that will fluoresce or otherwise exhibit color upon exposure to ultraviolet or visible light. To “fluoresce” will be understood as emitting light following absorption of light or other electromagnetic radiation. Examples of such conjugated compounds, often referred to as “tags,” include acridine, anthraquinone, coumarin, diphenylmethane, diphenylnaphthlymethane, quinoline, stilbene, triphenylmethane, anthracine and / or molecules containing any of these moieties and / or derivatives of any of these such as rhodamines, phenanthridines, oxazines, fluorones, cyanines and / or acridines.Table A: Structure of Conjugated CompoundsCompound StructureCatechol VioletSynonyms: OCatecholsulfonphthalein; JL. OH Pyrocatecholsulfonephthalein; [T T?HPyrocatechol Violet >ro=s=o1 J I JXylenol OrangeSynonym: zO3,3'-Bis[V, / V- ou)H bis(carboxymethyl)aminomethyl]- o-cresolsulfonephth aleintetrasodium salt t A k - — y, / / Y OH YO / \ L OHHO 1 9L 'tr OHOH

[0084] The composition may comprise the conjugated compound in an amount of at least 0.01 percent by weight based on total weight of the composition, such as at least 0.02 percent by weight. The composition may comprise the conjugated compound in an amount of no more than 1 percent by weight based on total weight of the composition, such as no more than 0.5 percent by weight. The composition may comprise the conjugated compound in an amount of 0.01 percent by weight to 1 percent by weight based on total weight of the composition, such as 0.02 to 0.5 percent by weight.Additives

[0085] The compositions disclosed herein optionally may comprise an additive in amounts known to those skilled in the art. Such additives include an additional polymer, a cure retarder, a cure accelerator, water, a rheology modifier, a reactive diluent, a non-reactive diluent, a dispersant, a tackifier, a thermoplastic polymer, a surfactant, a flame retardant, a UV light absorber and / or stabilizer, a light stabilizer, a colorant, a tint, a solvent such as an organic solvent, a plasticizer, an adhesion promoter such as an acid and / or an acid derivative, a filler such as a clay, an inorganic mineral, an abrasion-resistant particle, a silane, a phosphatized epoxy, a moisture scavenger, and other customary additives known to those skilled in the art. As used herein, the term “solvent” refers to a molecule or a compound that is used to lower the viscosityof a resin, volatilizes under ambient conditions, and does not have a reactive functional group capable of reacting with molecules or compounds in the composition. As used herein, the term “reactive diluent” refers to a molecule or a compound that is used to lower the viscosity of a resin but that has at least one functional group capable of reacting with molecules or compounds in a composition. As used herein, “colorants” refers to any substance that imparts color and / or other opacity and / or other visual effect to the composition. The skilled person will understand that the selection of an additive and the amount of such additive depends on the cure chemistry of the composition and the desired rate of cure and must be compatible with the sulfur-containing compound and / or the curing agent.

[0086] The composition may be substantially free, essentially free, or completely free of hexavalent chromium.

[0087] The composition may be substantially free, essentially free, or completely free of fluorO-containing polymer.

[0088] The composition may have a total solids content of at least 40 percent by weight based on total weight of the composition, such as at least 60 percent by weight. The composition may have a total solids content of no more than 100 percent by weight based on total weight of the composition, such as no more than 95 percent by weight. The composition may have a total solids content of 40 percent by weight to 100 percent by weight based on total weight of the composition, such as 60 percent by weight to 95 percent by weight. As used herein, “total solids” refers to the non-volatile content of the composition, i.e., materials which will not volatilize when heated to 110°C and standard atmospheric pressure (101325 Pa) for 60 minutes.

[0089] The base of the compositions disclosed herein may have a viscosity of 10 P to 150 P measured using a viscometer with a No. 4 spindle at a speed of 10 RPM under ambient condition, such as 1,000 P to 12,000 P measured using a viscometer with a No. 7 spindle at a speed of 2 RPM under ambient condition, such as 1,000 P to 12,000 P measured using a viscometer with a No. 6 spindle at a speed of 10 RPM under ambient condition, such as 100 P to 600 P measured using a viscometer with a No. 6 spindle at a speed of 10 RPM under ambient condition.

[0090] The compositions disclosed herein may be thermoset. A “thermoset” composition irreversibly hardens upon curing.

[0091] The composition may be provided as a one-component composition or as a two-component (or higher) composition.

[0092] The IK composition may comprise, or consist essentially of, or consist of: a filmforming resin comprising a film-forming binder comprising a sulfur-containing compound; magnesium oxide; and a second corrosion inhibitor in addition to the magnesium oxide. The composition optionally may further comprise a curing agent, and / or an additive.

[0093] The 2K (or higher) composition may comprise, or consist essentially of, or consist of: a film-forming binder comprising, or consisting essentially of, or consisting of: a first component comprising, or consisting essentially of, or consisting of, a sulfur-containing compound; and a second component comprising, or consisting essentially of, or consisting of, a curing agent. The first component, the second component, and / or a third component may further comprise magnesium oxide, a second corrosion inhibitor, and / or an additive as described above. The first and second components (and the optional third component) may be mixed together immediately prior to use.

[0094] The compositions of a two-component composition may be mixed and provided as pre-mixed frozen compositions (PMF). PMFs may be packaged, for example, in a cartridge, a cartridge and plunger, a syringe, or may be supplied as a tape, a cap, or any preformed geometry. PMFs may be cured by external factors, such as EMR. In examples, the PMF may be stored at temperatures of -100°C to -15°C, such as -100°C to -25°C, such as -100°C to -40°C, such as -75°C to -15°C, such as -75°C to -25°C, such as -75°C to -40°C, to inhibit curing. As used herein, the term “inhibiting,” when used with respect to curing, refers to restraining, impeding, slowing or interfering with a particular reaction or function. This can be accomplished in a number of ways, for example, controlling the environment to which the composition is exposed, such as limiting the composition’s exposure to ambient conditions.

[0095] The compositions may be used to make pre-molded parts such as seal caps, gaskets, O- rings, shims, washers, grommets, spacers, packing, cushions, mating material, flanges, plugs, and the like. The composition may be in a fully cured condition but may also be partially cured. As used herein, the term “pre-molded sealant part” refers to parts that have been formed from a composition into a predetermined shape and at least partially cured to retain that shape. Although the parts are referred to herein as being “pre-molded”, the parts can be made by any suitable method, such as molding, extrusion, additivemanufacturing, 3D printing and the like. The sealants and pre-molded parts made by the methods disclosed herein have the ability, when cured, to resist atmospheric conditions such as moisture and temperature and at least partially block the transmission of materials such as water, water vapor, fuel, solvents, and / or liquids and gases.Methods and Cured Compositions

[0096] Compositions disclosed herein may be prepared using any suitable method, such as manual stirring or air or electric mixing, such as with blade stirrers, or static mixing, magnetic stir bars, and the like. The disclosed compositions may be formulated as a sealant composition, such as a Class F sealant composition, a class B sealant composition, a class C sealant composition, and / or a Class A sealant composition. The disclosed compositions may be formulated as a coating composition, such as a primer composition, a basecoat composition, a topcoat composition, a gap filler composition, and / or an adhesive composition. When cured, the disclosed compositions may form a sealant, such as a Class F sealant, a class B sealant, a class C sealant, and / or a Class A sealant. The disclosed compositions, when cured, may form a coating, such as a primer, a basecoat, a topcoat, a gap filler, and / or an adhesive.

[0097] The compositions disclosed herein may be applied to an article or substrate using spray coating, roller coating, coil coating, dip coating, precision coating, spin coating techniques, casting, molding, machining, extruding, pressing, grouting, caulking, spreading, and the like.

[0098] Once the composition is deposited onto the substrate, it can be dried or cured by any suitable means. Examples of such suitable curing techniques include curing at ambient conditions, elevated temperature, and / or exposure to actinic radiation. As used herein, “ambient” conditions refer to room temperature (20°C ± 5°C) and humidity conditions (20% relative humidity to 80% relative humidity). As used herein, “elevated” temperatures refer to temperatures of 30°C or higher. Elevated temperatures may be achieved by baking in a thermal oven, induction heating, and / or infrared heating. The composition may be allowed to fully cure at room temperature and for any desired time period, such as for two weeks. Upon cure, a coating layer is formed on the substrate.

[0099] Upon cure, the sealant and / or the coating may have any desired dry film thickness (“DFT”). The sealants and / or coatings formed from any of the compositions disclosed herein may impart corrosion inhibition to a metallic substrate. For example, as discussed in more detailbelow, the sealants and / or coatings impart excellent corrosion resistance and swell resistance. This was a surprising and unexpected result.

[0100] It was unexpectedly discovered that a polysulfide sealant formed from a sprayable composition including both magnesium oxide and a metal oxide, a mixed metal oxide, a metal nitrate, an organic nitrate, and / or a conjugated compound, applied to a AL 2024-T3 substrate, resulted in improved corrosion resistance following NSS, as demonstrated by a corrosion rating score (described in the Examples) of 25 or lower.

[0101] It was also unexpectedly discovered that a polysulfide sealant formed from a sprayable composition including both magnesium oxide and a metal oxide, a mixed metal oxide, a metal nitrate, an organic nitrate, and / or a conjugated compound, applied to a AL 7075-T6 substrate, resulted in a corrosion rating score (described in the Examples) of lower than 15.

[0102] It was also unexpectedly discovered that a polysulfide sealant formed from a sprayable composition including both magnesium oxide and a metal oxide, a mixed metal oxide, a metal nitrate, an organic nitrate, and / or a conjugated compound (with the exception of neodymium nitrate (0.15 percent by weight based on total composition weight) and iconazole (0.25 percent by weight based on total composition weight), applied to a substrate, resulted in reduced filament length compared to a polysulfide sealant formed from a sprayable composition including magnesium oxide but not a second corrosion inhibitor.

[0103] It was also unexpectedly discovered that a polysulfide sealant formed from a sprayable composition including both magnesium oxide and a metal oxide, a mixed metal oxide, a metal nitrate, an organic nitrate, and / or a conjugated compound, resulted in swelling of less than 30% by volume following water exposure at 60°C compared to a polysulfide sealant formed from a sprayable composition including magnesium oxide but not a second corrosion inhibitor.

[0104] It was also unexpectedly discovered that a polysulfide sealant formed from a sprayable composition including both magnesium oxide and a metal nitrate, a conjugated compound, or an organic azole, resulted in reduced swelling following water exposure to 77 ± 5ºF compared to a polysulfide sealant formed from a sprayable composition including magnesium oxide but not a second corrosion inhibitor.

[0105] It was also unexpectedly discovered that a polysulfide sealant formed from a composition including both magnesium oxide and lithium vanadium oxide, neodymium nitrate.catechol violet, or praseodymium nitrate, resulted in a corrosion rating score (described in the Examples) of 30 or less.

[0106] It was also unexpectedly discovered that a polythioether sealant formed from a composition including both magnesium oxide and a metal nitrate, an organic nitrate, a metal oxide, or a mixed metal oxide, resulted in a corrosion rating score (described in the Examples) lower than polythioether sealants formed from a composition including magnesium oxide but no second corrosion inhibitor.Additive Manufacturing

[0107] The coating compositions of the present disclosure may be used in any suitable additive manufacturing technology, such as three-dimensional (3D) printing, extrusion, jetting, and binder jetting. Any suitable mixing, delivery, and 3D printing equipment known to those skilled in the art may be used.

[0108] Methods provided by the present disclosure include printing the composition on a fabricated part. Methods provided by the present disclosure include directly printing and / or manufacturing of parts or articles by additive manufacturing processes such as 3D printing. The entire part can be formed from one of the compositions disclosed herein and / or one or more surfaces of a part can be formed from a composition provided by the present disclosure. In addition, internal regions of a part can be formed from a composition provided by the present disclosure.Substrates

[0109] The present disclosure is further directed to substrates coated at least in part with a coating deposited from any of the coating compositions disclosed herein. Suitable substrates include metal substrates, such as flexible and rigid metal substrates, metal alloy substrates, and / or substrates that have been metallized, such as nickel-plated plastic. Additionally, substrates may comprise non-metal substrates, for example, polymeric materials, such as plastics including filled and unfilled thermoplastic or thermoset materials and / or composite materials such as. for example, plastic, fiberglass, and / or materials comprising carbon fibers and / or conductive carbon. Substrates may include two or more materials in any combination. For example, the substrate may comprise two different metals, or a metal and a metal alloy, or a metal and a metal alloy and one or more composite materials.

[0110] The metal or metal alloy may comprise, for example, cold rolled steel, hot rolled steel, steel coated with zinc metal, zinc compounds, or zinc alloys, such as electrogalvanized steel, hot-dipped galvanized steel, galvannealed steel, GALVANNEAL steel, nickel-plated steel, steel plated with zinc alloy, and stainless steel, such as martensitic, duplex, ferritic, austenitic, and / or precipitation hardened stainless steel. Steel substrates (such as cold rolled steel or any of the steel substrates listed above) coated with a weldable, zinc-rich or iron phosphide-rich organic coating are also suitable for use in the present disclosure. Such weldable coating compositions are disclosed in U. S. Patent Nos. 4,157,924 and 4,186,036. incorporated herein by reference. The substrate may comprise aluminum, aluminum alloys, zinc-aluminum alloys such as GALFAN, GALVALUME, aluminum plated steel, and aluminum alloy plated steel substrates. Non-limiting examples of aluminum alloys include the 1000, 2000, 3000, 4000, 5000. 6000, or 7000 series, such as 2024, 2024-T3, 7075, 7075-T6, as well as clad aluminum alloys, such as 2024-T3 clad, and cast aluminum alloys, such as, for example, the A356 series. The substrate may comprise a magnesium alloy. Non-limiting examples of suitable magnesium alloys include those of the AZ31B, AZ91C, AM60B, or EV31A series. The substrate used in the present disclosure may also comprise other suitable non-ferrous metals such as titanium or copper, as well as alloys of these materials.

[0111] The substrate may comprise a multi-metal article. As used herein, the term “multi-metal article” refers to (1) an article that has at least one surface comprised of a first metal and at least one surface comprised of a second metal that is different from the first metal, (2) a first article that has at least one surface comprised of a first metal and a second article that has at least one surface comprised of a second metal that is different from the first metal, or (3) both (1) and (2). The substrate may comprise surfaces or parts of different substrate materials that are adjacent or joined together, such as, for example, a galvanic assembly.

[0112] Substrates comprising a coating layer deposited from the coating compositions of the present disclosure may be uncoated prior to a coating layer being deposited thereon.

[0113] Substrates comprising a coating layer deposited from the coating compositions of the present disclosure may comprise one or more additional layers over and / or under the layers; these multiple layers are referred to herein as a “multi-layer coating system” or “coating stack.” Additional layers may comprise an aluminum cladding layer, an anodized oxide layer, a conversion coating, a non-chromate treatment, and / or a pretreatment layer. The pretreatmentlayer may comprise, for example, a pretreatment layer such as those described in U.S. Patent Nos. 4,793,867 and 5,588,989, incorporated herein by reference, a zirconium containing pretreatment solution such as, for example, those described in U.S. Patent Nos. 7,749,368 and 8,673,091, incorporated herein by reference, a phosphate containing pretreatment solution (e.g., a zinc phosphate containing pretreatment solution), and / or a solgel, such as those comprising alkoxy-silanes, alkoxy-zirconates, and / or alkoxy-titanates. The coating composition of the present disclosure may be applied over at least a portion of the pretreated layer; one or more additional coating layers may be applied over at least a portion of the present coating layer. Additional coating layers may comprise primers, basecoats, color coats, monocoats, clear coats, and / or topcoats. Suitable additional coating layers include any of those known in the art, and each independently may be water-based, solvent-based, in solid particulate form (i.e., a powder coating composition), or in the form of a powder slurry. The additional coating layers may each be cured independently or optionally applied “wet-on-wet” and cured simultaneously. As used herein, “wet-on- wet” refers to a process wherein a coating, for example, a clear coat, is applied over a substantially uncured different coating, for example, a color coat, and both coatings are cured simultaneously. Different layers in the coatings stack may contain components that impart a desired property, visual effect, and / or color effect to the coating, such as corrosion inhibitors; conductive agents such as graphene, conductive carbon black, conductive polymers, or conductive additives; pigments such as those described in U.S. Patent No. 10,844,256 at 8:18-43, the cited portions thereof incorporated herein by reference, or other chromatic pigments, and the like.

[0114] The substrate may be new (i.e., newly constructed or fabricated) or it may be refurbished, such as in the case of refinishing or repairing a component of an automobile or aircraft.

[0115] The substrate may be in any form, such as a sheet, a foil, a laminate foil, a pad, a fabricated part, a component, and / or an article. The substrate may be in the shape of a cylinder, such as a pipe, including, for example, a cast iron pipe. The substrate may also comprise conductive or non-conductive substrates at least partially coated with a conductive coating. The conductive coating may comprise a conductive agent such as, for example, graphene, conductive carbon black, conductive polymers, and / or conductive additives.

[0116] The substrate may optionally be subjected to other treatments prior to coating. For example, the substrate may be cleaned, cleaned and deoxidized, anodized, acid pickled, plasma treated, laser treated, or ion vapor deposition (IVD) treated. The substrate may be abraded, such as wet or dry abraded with a pad, such as a 3M SCOTCH-BRITE pad.

[0117] Applications of the compositions disclosed herein are not limited. The coating compositions disclosed herein may be suitable for use in various industrial or transportation applications including appliance, coil, automotive applications, commercial transport applications, rail locomotive, marine applications, and / or aerospace applications. Suitable substrates for use in the present disclosure include those that are used in the form of sheets or coils, or in the assembly of appliances or of vehicular bodies (such as door, body panel, trunk deck lid, roof panel, hood, roof and / or stringers, rivets, landing gear components, and / or skins used on an aircraft), vehicular frames, vehicular parts, motorcycles, wheels, and industrial structures and components. As used herein, “vehicle” or variations thereof includes all types of aircraft, spacecraft, watercraft, and ground vehicles. A vehicle may be an aerospace vehicle including aircraft such as airplanes, including private aircraft, and small, medium, or large commercial passenger, freight, civilian, and military aircraft; helicopters, including private, commercial, and military helicopters; or rockets and other spacecraft. A vehicle can include a ground vehicle, such as tanks, armored cars, trailers, cars, trucks, buses, vans, construction vehicles, golf carts, motorcycles, bicycles, trains, and railroad cars. A vehicle can also include watercrafts such as, for example, ships, boats, and hovercraft. The coating composition may be utilized to coat surfaces and parts thereof. A part may include multiple surfaces. A part may include a portion of a larger part, assembly, or apparatus. A portion of a part may be coated with the coating composition of the present disclosure, or the entire part may be coated. An “aircraft part” refers to any part used on any aircraft, internally or externally, and made of any substrate.

[0118] The coated substrate may comprise a three-dimensional component formed by an additive manufacturing process, such as a three-dimensional formed composite.Definitions

[0119] For purposes of this detailed description, it is to be understood that the disclosure may assume alternative variations and step sequences, except where expressly specified to the contrary.

[0120] The numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.

[0121] Also, any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10. that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.

[0122] As used herein, “including,” “containing” and like terms are understood in the context of this application to be synonymous with “comprising” and are therefore open-ended and do not exclude the presence of additional undescribed or unrecited elements, materials, ingredients or method steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified element, ingredient or method step. As used herein, “consisting essentially of’ is understood in the context of this application to include the specified elements, materials, ingredients or method steps “and those that do not materially affect the basic and novel characteristic(s)” of what is being described.

[0123] In addition, in this application, the use of “or” means “and / or” unless specifically stated otherwise, even though “and / or” may be explicitly used in certain instances.

[0124] As used herein, the terms “on,” “onto,” “applied on,” “applied onto,” “formed on,” “deposited on,” “deposited onto,” and the like mean formed, overlaid, deposited, or provided on, but not necessarily in contact with, a substrate surface. For example, a composition “applied onto” a substrate surface does not preclude the presence of one or more other intervening coating layers or films of the same or different composition located between the composition and the substrate surface.

[0125] As used herein, a “composition” includes both a “coating composition” and a “sealant composition.”

[0126] As used herein, a “coating composition” refers to a solution, mixture, or a dispersion that is capable of producing a coating on a substrate surface. “Coating” as used herein includes films, layers and the like.

[0127] As used herein, a “sealant composition” refers to a solution, mixture, or a dispersion that is capable of producing a sealant in its cured state.

[0128] As used herein, a “sealant” refers to a coating that is a barrier to movement of vapor and / or liquid from a first side of the sealant to a second side of the sealant. In examples, a sealant may (i) have an elongation of at least 100% and a tensile strength of at least 250 psi when measured in accordance with the procedure described in AMS 3279, §3.3.17.1, test procedure AS5127_1D, §§ 5.6, 5.8, and 5.9, and / or may be (ii) fuel resistant as determined by AS5127TM / 1D, 7.5. As used herein, the term “fuel resistant” means that a coating, such as a sealant, has a percent volume swell of not greater than 40%, in some cases not greater than 25%, in some cases not greater than 20%, in yet other cases not more than 10%, after immersion for one week at 140°F (60°C). and ambient pressure.

[0129] As used herein, the term “cure,” “curing,” and similar terms, means that the reactive components that form the composition are crosslinked (i.e.. interact and / or react) to form a coating or a bond. In the case of a 2K composition, the composition begins to cure when the components of the composition are mixed, resulting in the reaction of the reactive functional groups of the components of the composition and / or the physical interaction of the components of the composition.

[0130] The term “curable,” as used in connection with a coating composition, means that the composition can be cured under ambient and / or slightly thermal conditions.

[0131] As used herein, “polymer” refers to oligomers, homopolymers, and copolymers.

[0132] As used herein, a “corrosion inhibitor” refers to a compound that inhibits the corrosion of metals. The effectiveness of the corrosion inhibitor in a cured coating in preventing corrosion of the substrate upon which the coating composition is applied and cured may be demonstrated, for example, by salt spray corrosion testing according to ASTM B117-19 and / or filiform testing according to MIL-PRF-23377K.

[0133] As used herein, the term “alkali metal” refers to an element that is in Group 1 of the Periodic Table in IUPAC numbering.

[0134] As used herein, the term “alkali metal compound refers to a compound that includes an alkali metal.

[0135] As used herein, the term “transition metal” refers to an element that is in Group 3 to 12 of the Periodic Table in IUPAC numbering.

[0136] As used herein, the term “transition metal compound” refers to a compound that includes a transition metal.

[0137] As used herein, the term “rare earth metal” refers to an element that is in the lanthanide series, scandium, and yttrium.

[0138] As used herein, the term “rare earth metal compound” refers to a compound that includes a rare earth metal.

[0139] As used herein, the term “lanthanide metal” refers to an element having an atomic number of 57 to 71.

[0140] As used herein, the term “lanthanide metal compound” refers to a compound that includes a lanthanide metal.

[0141] As used herein, unless indicated otherwise, the term “substantially free” means that a particular material is not purposefully added to a mixture or composition, respectively, and is only present as an impurity in a trace amount of less than 0.05% by weight based on a total weight of the mixture or composition, respectively. As used herein, unless indicated otherwise, the term “essentially free” means that a particular material is only present in an amount of less than 0.01% by weight based on a total weight of the mixture or composition, respectively. As used herein, unless indicated otherwise, the term “completely free” means that a mixture or composition, respectively, does not comprise a particular material, i.e., the mixture or composition comprises 0% by weight of such material.Aspects

[0142] In view of the foregoing description, the present disclosure relates to the following Aspects 1 to 86 without being limited thereto.

[0143] 1. A composition comprising:a film-forming binder comprising a base comprising a film-forming resin comprising a sulfur-containing compound;magnesium oxide; anda second corrosion inhibitor in addition to the magnesium oxide

[0144] 2. The composition of aspect 1, wherein the sulfur-containing compound comprises a polythiol and / or a polythioether.

[0145] 3. The composition of aspect 1 or aspect 2, wherein the sulfur-containing compound comprises a thiol functional group.

[0146] 4. The composition of any preceding aspect, wherein the sulfur-containing compound is a monomer, a polymer, and / or an oligomer.

[0147] 5. The composition of any of aspects 2 to 4, wherein the polythiol has a weight average molecular weight of at least 80 g / mol determined by gel permeation chromatography (GPC) using polystyrene standards for calibration, such as at least 100 g / mol.

[0148] 6. The composition of any of aspects 2 to 5, wherein the polythiol has a weight average molecular weight of no more than 40,000 g / mol determined by gel permeation chromatography (GPC) using polystyrene standards for calibration, such as no more than 30,000 g / mol.

[0149] 7. The composition of any of aspects 2 to 6, wherein the polythiol has a weight average molecular weight of 80 g / mol to 40,000 g / mol determined by gel permeation chromatography (GPC) using polystyrene standards for calibration, such as 100 g / mol to 30,000 g / mol.

[0150] 8. The composition of any of aspects 2 to 7, wherein the polythiol has a weight average molecular weight of at least 150 g / mol determined by gel permeation chromatography (GPC) using polystyrene standards for calibration, such as no more than 20,000 g / mol.

[0151] 9. The composition of any of aspects 2 to 8, wherein the polythiol has a weight average molecular weight of 150 g / mol to 20,000 g / mol determined by gel permeation chromatography (GPC) using polystyrene standards for calibration.

[0152] 10. The composition of any preceding aspect, wherein the film-forming resin further comprises a silicone resin.

[0153] 11. The composition of any preceding aspect, comprising the film-forming binder in an amount of at least 80 percent by weight based on total weight of the composition, such as at least 85 percent by weight.

[0154] 12. The composition of any preceding aspect, comprising the film-forming binder in an amount of no more than 99.5 percent by weight based on total weight of the composition, such as no more than 90 percent by weight.

[0155] 13. The composition of any preceding aspect, comprising the film-forming binder in an amount of 80 percent by weight to 99.5 percent by weight based on total weight of the composition, such as 85 percent by weight to 90 percent by weight.

[0156] 14. The composition of any preceding aspect, wherein the film-forming binder further comprises a curing agent.

[0157] 15. The composition of aspect 14, wherein the curing agent comprises a metal oxide, an organic peroxide.

[0158] 16. The composition of aspect 14 or aspect 15, wherein the curing agent comprises zinc oxide, lead oxide, lead dioxide, lead peroxide, manganese dioxide, sodium dichromate, sodium perborate, sodium perborate monohydrate, potassium permanganate, calcium dioxide, calcium peroxide, barium peroxide, lithium peroxide, zinc peroxide, zinc chromate, barium oxide, and / or alkaline dichromate.

[0159] 17. The composition of any of aspects 14 to 16, wherein the curing agent comprises cumene hydroperoxide, and / or t-butyl hydroperoxide.

[0160] 18. The composition of any of aspects 14 to 17, wherein the curing agent comprises an epoxy resin, such as hydantoin diepoxide, diglycidyl ether of bisphenol-A, diglycidyl ether of bisphenol-F, Novolak type epoxides, and / or an epoxidized unsaturated and phenolic resins.

[0161] 19. The composition of any of aspects 14 to 18, wherein the curing agent comprises an unsaturated compound such as acrylic and methacrylic esters, unsaturated synthetic or naturally occurring resin compounds, TAC, and / or olefinic terminated compounds.

[0162] 20. The composition of any preceding aspect, wherein the magnesium oxide comprises nano-sized MgO and / or micron-sized MgO, wherein average particle size is determined by visually examining a micrograph of a transmission electron microscopy (“TEM”) image.

[0163] 21. The composition of any preceding aspect, wherein the MgO has a number average particle size of at least 0.1 micron, such as at least 1 micron measured by TEM.

[0164] 22. The composition of any preceding aspect, wherein the MgO has a number average particle size of no more than 50 microns, such as no more than 30 microns measured by TEM.

[0165] 23. The composition of any preceding aspect, wherein the MgO has a number average particle size of 0.1 microns to 50 microns, such as 1 micron to 30 microns measured by TEM.

[0166] 24. The composition of any preceding aspect, wherein the MgO has a number average particle size of at least 10 nm measured by TEM.

[0167] 25. The composition of any preceding aspect, wherein the MgO has a number average particle size of no more than 499 nm, such as no more than 100 nm measured by TEM.

[0168] 26. The composition of any preceding aspect, wherein the MgO has a number average particle size of 10 nm to 499 nm, such as 10 nm to 100 nm measured by TEM.

[0169] 27. The composition of any preceding aspect, wherein the MgO comprises ultrafine MgO particles.

[0170] 28. The composition of any preceding aspect, wherein the MgO has a B. E. T. specific surface area of at least 0.05 square meters per gram (m2 / g), such as at least 0.1 m2 / g.

[0171] 29. The composition of any preceding aspect, wherein the MgO has a B. E. T specific surface area of at least 10 m2 / g, such as at least 30 m2 / g.

[0172] 30. The composition of any preceding aspect, wherein the MgO has a B. E. T. specific surface area of no more than 500 m2 / g, such as no more than 200 m2 / g.

[0173] 31. The composition of any preceding aspect, wherein the MgO has a B. E. T. specific surface area of no more than 100 m2 / g, such as no more than 70 m2 / g.

[0174] 32. The composition of any preceding aspect, wherein the MgO has a B. E. T. specific surface area of 0.05 m2 / g to 500 m2 / g, such as 0.1 m2 / g to 200 m2 / g.

[0175] 33. The composition of any preceding aspect, wherein the MgO has a B. E. T. specific surface area of 30 m2 / g to 200 m2 / g, such as 30 m2 / g to 70 m2 / g.

[0176] 34. The composition of any preceding aspect, wherein the MgO has an equivalent spherical diameter of no more than 200 nm, such as no more than 100 nm measured using a particle size analyzer.

[0177] 35. The composition of any preceding aspect, wherein the MgO has an equivalent spherical diameter of 5 nm to 50 nm measured using a particle size analyzer.

[0178] 36. The composition of any preceding aspect, wherein the MgO particle has a spherical morphology, is cubic, platy, polyhedric, or acicular (elongated or fibrous).

[0179] 37. The composition of any preceding aspect, wherein the MgO particles are covered with a polymeric gel.

[0180] 38. The composition of any preceding aspect, comprising the MgO in an amount of at least 0.1 percent by weight based on total weight of the composition, such as at least 1 percent by weight.

[0181] 39. The composition of any preceding aspect, comprising the MgO in an amount of no more than 10 percent by weight based on total weight of the composition, such as no more than 8 percent by weight.

[0182] 40. The composition of any preceding aspect, comprising the MgO in an amount of 0.1 percent by weight to 10 percent by weight based on total weight of the composition, such as 1 percent by weight to 8 percent by weight.

[0183] 41. The composition of any preceding aspect, further comprising a second corrosion inhibitor in addition to the MgO.

[0184] 42. The composition of aspect 41, wherein the second corrosion inhibitor comprises a metal oxide, a mixed metal oxide, a nitrate, and / or a conjugated compound.

[0185] 43. The composition of aspect 42, wherein the nitrate comprises a metal nitrate and / or an organic nitrate.

[0186] 44. The composition of aspect 43, wherein the metal nitrate comprises a rare earth metal nitrate, a lanthanide metal nitrate, and / or a transition metal nitrate, such as neodymium nitrate, yttrium nitrate, terbium nitrate, and / or praseodymium nitrate.

[0187] 45. The composition of aspect 43 or aspect 44, comprising the metal nitrate in an amount of at least 0.05 percent by weight based on total weight of the composition, such as at least 0.25 percent by weight.

[0188] 46. The composition of any of aspects 43 to 45. comprising the metal nitrate in an amount of no more than 3 percent by weight based on total weight of the composition, such as no more than 2 percent by weight.

[0189] 47. The composition of any of aspects 43 to 46. comprising the metal nitrate in an amount of 0.05 percent by weight to 3 percent by weight based on total weight of the composition, such as 0.25 percent by weight to 2 percent by weight.

[0190] 48. The composition of any of aspects 43 to 47, wherein the organic nitrate comprises an azole.

[0191] 49. The composition of aspect 48, wherein the azole comprises a cyclic compound comprising 1 nitrogen atom, a cyclic compound comprising 2 or more nitrogen atoms, a cyclic compound comprising 1 nitrogen atom and 1 oxygen atom, and / or a cyclic compound comprising 1 nitrogen atom and 1 sulfur atom, such as a pyrrole, a pyrazole, an imidazole, atriazole, a tetrazole, a pentazole, an oxazole, an isoxazole, a thiazole, and / or an isothiazole, such as isoconazole nitrate and / or econazole nitrate.

[0192] 50. The composition of any of aspects 43 to 49, comprising the organic nitrate in an amount of at least 0.05 percent by weight based on total weight of the composition, such as at least 0.25 percent by weight.

[0193] 51. The composition of any of aspects 43 to 50, comprising the organic nitrate in an amount of no more than 3 percent by weight based on total weight of the composition, such as no more than 2 percent by weight.

[0194] 52. The composition of any of aspects 43 to 51, comprising the organic nitrate in an amount of 0.05 percent by weight to 3 percent by weight based on total weight of the composition, such as 0.25 percent by weight to 2 percent by weight.

[0195] 53. The composition of any of aspects 42 to 52, wherein the metal oxide and / or the mixed metal oxide comprise an alkali metal oxide, a lanthanide metal oxide, and / or a transition metal oxide such as lithium, vanadium, praseodymium, terbium, yttrium, and / or neodymium.

[0196] 54. The composition of any of aspects 42 to 52, wherein the mixed metal oxide comprises lithium vanadium oxide.

[0197] 55. The composition of any of aspects 42 to 54, comprising the metal oxide and / or the mixed metal oxide in an amount of at least 0.1 percent by weight based on total weight of the composition, such as at least 0.25 percent by weight.

[0198] 56. The composition of any of aspects 42 to 55, comprising the metal oxide and / or the mixed metal oxide in an amount of no more than 10 percent by weight based on total weight of the composition, such as no more than 7 percent by weight.

[0199] 57. The composition of any of aspects 42 to 56, comprising the metal oxide and / or the mixed metal oxide in an amount of 0.1 percent by weight to 10 percent by weight based on total weight of the composition, such as 0.25 percent by weight to 7 percent by weight.

[0200] 58. The composition of any of aspects 42 to 57, comprising the metal oxide and / or the mixed metal oxide in an amount of at least 0.4 percent by weight, such as no more than 5 percent by weight.

[0201] 59. The composition of any of aspects 42 to 58, comprising the metal oxide and / or the mixed metal oxide in an amount of 0.4 percent by weight to 5 percent by weight.

[0202] 60. The composition of any of aspects 42 to 59, wherein the conjugated compound comprises methyl orange, xylenol orange, catechol violet, bromophenol blue, green and purple, eriochrome black T, methyl blue, celestine blue, hematoxylin, calmagite, and / or gallocyanine.

[0203] 61. The composition of any of aspects 42 to 60. comprising the conjugated compound in an amount of at least 0.01 percent by weight based on total weight of the composition, such as at least 0.02 percent by weight.

[0204] 62. The composition of any of aspects 42 to 61, comprising the conjugated compound in an amount of no more than 1 percent by weight based on total weight of the composition, such as no more than 0.5 percent by weight.

[0205] 63. The composition of any of aspects 42 to 62, comprising the conjugated compound in an amount of 0.01 percent by weight to 1 percent by weight based on total weight of the composition, such as 0.02 percent by weight to 0.5 percent by weight.

[0206] 64. The composition of any preceding aspect, further comprising an additive.

[0207] 65. The composition of any preceding aspect, wherein the composition is substantially free, essentially free, or completely free of hexavalent chromium and / or a fluorocontaining polymer.

[0208] 66. The composition of any preceding aspect, having a total solids content of at least 40 percent by weight based on total weight of the composition, such as at least 60 percent by weight.

[0209] 67. The composition of any preceding aspect, having a total solids content of 100 percent by weight based on total weight of the composition, such as no more than 95 percent by weight.

[0210] 68. The composition of any preceding aspect, having a total solids content of 40 percent by weight to 100 percent by weight based on total weight of the composition, such as 60 percent by weight to 95 percent by weight.

[0211] 69. The composition of any preceding aspect, wherein the base has a viscosity of 10 P to 150 P measured using a viscometer with a No. 4 spindle at a speed of 10 RPM under ambient conditions.

[0212] 70. The composition of any of aspects 1 to 68, wherein the base has a viscosity of 1,000 P to 12,000 P measured using a viscometer with a No. 7 spindle at a speed of 2 RPM under ambient conditions.

[0213] 71. The composition of any of aspects 1 to 68, wherein the base has a viscosity of 1,000 P to 12,000 P measured using a viscometer with a No. 6 spindle at a speed of 10 RPM under ambient conditions.

[0214] 72. The composition of any of aspects 1 to 68, wherein the base has a viscosity of 100 P to 600 P measured using a viscometer with a No. 6 spindle at a speed of 10 RPM under ambient conditions.

[0215] 73. The composition of any preceding aspect, formulated as a thermoset, a 1K composition, a 2K composition, and / or a PMF.

[0216] 74. The composition of any preceding aspect, formulated as a Class A sealant composition, a Class B sealant composition, a Class C sealant composition, and / or a Class F sealant composition.

[0217] 75. The composition of any of aspects 1 to 73, formulated as a coating composition, such as a primer composition, a basecoat composition, a topcoat composition, a gap filler composition, and / or an adhesive composition.

[0218] 76. A sealant formed from the composition of any of aspects 1 to 74.

[0219] 77. The sealant of aspect 76, formed as a Class A sealant, a Class B sealant, a Class C sealant, and / or a Class F sealant.

[0220] 78. The sealant of aspect 76 or aspect 77, formulated as a Class F sealant and applied to an AL 2024-T3 substrate and having a corrosion rating score (described in the Examples) of 25 or lower.

[0221] 79. The sealant of any of aspects 76 to 78, formulated as a Class F sealant and applied to an AL 7075-T6 substrate and having a corrosion rating score (described in the Examples) of lower than 15.

[0222] 80. The sealant of any of aspects 76 or aspect 79, formulated as a Class F sealant and having a reduced filament length compared to a sealant formed from a polysulfide-containing composition comprising magnesium oxide but not a second corrosion inhibitor.

[0223] 81. The sealant of any of aspects 76 to 80, formulated as a Class F sealant and having a volume swell of less than 30% following water exposure at 60°C compared to a sealantformed from a polysulfide-containing composition comprising magnesium oxide but not a second corrosion inhibitor.

[0224] 82. The sealant of any of aspects 76 to 81. formulated as a Class F sealant and having a reduced volume swell following water exposure at 77 ± 5ºF compared to a sealant formed from a polysulfide-containing composition comprising magnesium oxide but not a second corrosion inhibitor.

[0225] 83. The sealant of aspect 76 or aspect 77, formulated as a class B sealant or a class C sealant and having a corrosion rating score (described in the Examples) of 30 or less.

[0226] 84. The sealant of aspect 76 or aspect 77, formed from a polythioether-containing composition and having a corrosion rating score (described in the Examples) lower than a polythioether-containing sealant formed from a composition including magnesium oxide but not a second corrosion inhibitor.

[0227] 85. A coating formed from the composition of any of aspects 1 to 73 and 75 on a surface of a substrate.

[0228] 86. The coating of aspect 85, comprising a primer, a basecoat, a topcoat, a gap filler, and / or an adhesive.Examples

[0229] The following examples are intended to illustrate the disclosure and should not be construed as limiting the disclosure in any way.Example A: Sprayable Sealant Compositions

[0230] Part B (Base) shown in Tables 1 to 12 below (amounts expressed in weight percent) were prepared as follows. Thioplast G1 (a mercaptofunctionalized polysulfide sealant commercially available from Nouryon, having an SH content of 18-20% and a molecular weight of 3,400 g / mol to 4,600 g / mol), additives, fillers, and corrosion inhibitors were added to a plastic cup (FlackTek), mixed by hand for 1 min then agitated in the centrifugal mixer, with the lid orifice taped over, per the following sequence: 15 sec at 1000 rpm, 15 sec at 1200 rpm, 60 sec at 1400 rpm. The sample was then hand mixed and agitated again in the centrifugal mixer under full vacuum for 60 seconds at 1600 rpm. The mixture was then allowed to cool to room temperature. Once cooled, methyl amyl ketone was then added and hand mixed in for 1 minute, then agitated for 1 minute at 1200 rpm in the centrifugal mixer with the lid orifice taped over. The fineness of grind was then checked using a Hegman grind gauge. If the target grind of 8 wasreached, then the formulation was diluted with ethyl acetate. If not, the material was passed over a 3-roll mill until the grind target of 8 was reached and then let down with ethyl acetate. After the solvent was added, the mixture was agitated for 1 min at 1200 rpm with the lid orifice sealed with tape. The material was then stored in a nitrogen purged container in a constant temperature and humidity room (77 ± 2 F, 50 ± 5 RH) until use.

[0231] The spray able sealant composition was made as follows. Part B, prepared as described above, was agitated using a paint shaker (RED Devil shaker- model RP1B CIR-10) for 3 minutes. In a container, the thoroughly mixed sealant part B was combined with activated manganese dioxide paste accelerator in a 100:10 ratio by weight. Once combined, the material was hand mixed, the container was sealed and then agitated using a paint shaker (RED Devil shaker- model RP1B CIR-10) for 3 minutes. Once thoroughly mixed, four parts (by volume) of ethyl acetate were then added and hand mixed for 30 seconds. Following the hand mixing, the sample was then agitated using a paint shaker (RED Devil shaker- model RP1B CIR-10) for 3 minutes.

[0232] Example 38 was a commercial chromium composition, prepared according to manufacturer’s instructions (PR-1432GP, commercially available from PPG Industries, Inc.).

[0233] A 3”x6”x0.04” panel of Al 2024-T3, obtained from Priority Metals (Orange County, CA) or a 3”x6”x0.04” panel of Al 7075-T6, obtained from Priority Metals (Orange County. CA) was solvent wiped on both sides with methyl ethyl ketone until the surface was visually free from grease and oil. It was then immersed in Bonderite C-AK 6849 (an aqueous alkaline degreaser available from Henkel AG & Co. KGaA (prepared according to manufacturer’s instructions) for 10 minutes at about 65 °C using agitation. The metal panel was then rinsed using a room temperature tap water spray rinse for 30 seconds, followed by a room temperature tap water immersion rinse for two minutes that was agitated, followed by a final room temperature spray rinse using deionized water for 30 seconds. The panel was then deoxidized using Bonderite C-IC SmutGo NC (a chromate-free cleaner available from Henkel AG & Co. KGaA) (prepared according to manufacturer’s instructions) for five minutes at 30°C using agitation. After deoxidization, the panel was then rinsed using a room temperature tap water spray rinse for 30 seconds, followed by a room temperature tap water immersion rinse with agitation for two minutes that was agitated, followed by a final room temperature spray rinseusing de-ionized water for 30 seconds. See Table 1. The substrate was then allowed to air dry at ambient conditions.Table 1. Cleaning Treatment ProtocolStep 1 2 3 4 5 6 7 8 Treat 6849 Tap Tap Tap SmutGo Tap Tap DI -ment rinse Immersio Rinse rinse Immersion rinse nTime 10 min 30 sec 2 min 30 sec 5 min 30 sec 2 min 30 sec Temp 65°C Ambie ambient ambient 40°C ambient ambient ambient ntImmerse Spray Immerse spray Immerse spray Immerse spray with with with withAgitation Agitation Agitation Agitation

[0234] One of the sprayable sealant composition described above and shown in Tables 2 to 13 was then poured into the cup of a cup spray gun and sprayed onto the substrate using an HVLP spray gun (Anest-Iwata, HVLP compliant spray gun, LPH-400-LVB-LVC-LVX, 1.4 LV tip) with a line pressure of 20 psi.

[0235] Viscosity was measured as follows. The base compound was stored in a sealed container at 77 ± 5ºF for at least 8 hours. The container was opened and the base was then mixed by slowing stirring for 3 minutes + 5 seconds. The container was closed and the base was allowed to stand for 1 hour + 5 minutes. Viscosity was measured using a Brookfield Model RVF viscometer using a No. 4 spindle at a speed of 10 RPM under ambient condition.Table 2. Neodymium nitrate (crystals)Constituents Example 1Thioplast G1 26.97Additives 2.68Fillers 30.33Nano- magnesium oxide 2.25Magnesium oxide (Maglite Y) 4.51Neodymium nitrate (crystal) 0.50Solvents 32.76Viscosity 16 poiseTotal 100.00Table 3. Neodymium nitrate (in ethyl acetate)Constituents Example 2 Example 3 Example 4 Thioplast G1 26.97 26.97 26.97 Additives 2.68 2.68 2.68 Fillers 30.68 32.33 30.33 Nano- magnesium oxide 2.25 2.25 2.25 Magnesium oxide (Maglite Y) 4.51 4.51 4.51 Neodymium nitrate (in ethyl 0.3 0.5 acetate) 0.15Solvents 32.76 32.76 32.76Total 100.00 100.00 100.00 Table 4. Yttrium nitrate (crystals)Constituents Example 5 Example 6 Example 7 Thioplast G1 26.51 26.41 26.51 Additives 2.64 2.64 2.64 Fillers 31.71 31.51 31.21 Nano- magnesium oxide 2.21 2.21 2.21 Magnesium oxide (Maglite Y) 4.43 4.43 4.43 Yttrium nitrate (crystals) 0.3 0.5 0.8 Solvents 32.20 32.20 32.20Total 100.00 100.00 100.00Table 5. Yttrium nitrate (aqueous solution)Constituents Example 8 Example 9 Example 10 Thioplast G1 26.51 26.51 26.51 Additives 2.64 2.64 2.64 Fillers 31.51 31.21 30.77Nano- magnesium oxide 2.21 2.21 2.21 Magnesium oxide (Maglite Y) 4.43 4.43 4.43 Yttrium nitrate (aqueous solution) 0.5 0.8 1.24Solvents 32.2 32.20 32.20 Viscosity 26 poiseTotal 100.00 100.00 100.00Table 6. Catechol violetConstituents Example 11 Example 12 Example 13 Thioplast G1 26.95 26.95 26.95 Additives 2.68 2.68 2.68 Fillers 30.835 30.81 30.76Nano- magnesium oxide 2.25 2.25 2.25 Magnesium oxide (Maglite Y) 4.51 4.51 4.51 Catechol violet 0.025 0.05 0.1Solvents 32.75 32.75 32.75 Viscosity 16 poiseTotal 100.0 100.0 100.0Table 7. Lithium vanadium oxideConstituents Example 14 Example 15 Example 16 Thioplast G1 26.84 26.84 26.84 Additives 2.67 2.67 2.67 Fillers 30.65 30.15 29.15 Nano- magnesium oxide 2.24 2.24 2.24 Magnesium oxide (Maglite Y) 4.49 4.49 4.49 Lithium vanadium oxide 0.5 1.0 2.0 Solvents 32.61 32.61 32.61 Viscosity 16 poiseTotal 100.0 100.0 100.0Table 8. Azole NitratesConstituents Example 17 Example 18 Example 19 Thioplast G1 27.55 27.55 27.55 Additives 2.74 2.74 2.74 Fillers 29.09 28.84 27.84Nano- magnesium oxide 2.30 2.30 2.30 Magnesium oxide (Maglite Y) 4.60 4.60 4.60 Econazole nitrate 0.25 0.5 1.5 Isoconazole nitrate 0 0 0Solvents 33.47 33.47 33.47 Viscosity 12 poiseTotal 100.0 100.0 100.0Table 8., coat’dConstituents Example 20 Example 21 Example 22 Thioplast G1 27.55 27.55 27.55 Additives 2.74 2.74 2.74 Fillers 29.09 28.84 27.84 Nano- magnesium oxide 2.30 2.30 2.30 Magnesium oxide (Maglite Y) 4.60 4.60 4.60 Econazole nitrate 0 0 0 Isoconazole nitrate 0.25 0.5 1.5 Solvents 33.47 33.47 33.47Total 100.0 100.0 100.00 Table 9. Metal Oxides (Comparatives)Constituents Example 23 Example 24 Example 25 Thioplast G1 26.51 26.51 26.51 Additives 2.64 2.64 2.64 Fillers 30.01 28.01 30.01 Nano- magnesium oxide 2.21 2.21 2.21 Magnesium oxide (Maglite Y) 4.43 4.43 4.43 Yttrium Oxide 2.0 4.0 0 Praseodymium Oxide 0 0 2.0 Terbium Oxide 0 0 0 Solvents 32.2 32.20 32.20Total 100.00 100.00 100.00Table 9, cont’dConstituents Example 26 Example 27 Example 28 Thioplast G1 26.51 26.51 26.51 Additives 2.64 2.64 2.64 Fillers 25.01 30.01 28.01 Nano- magnesium oxide 2.21 2.21 2.21 Magnesium oxide (Maglite Y) 4.43 4.43 4.43 Yttrium Oxide 0 0 0 Praseodymium Oxide 7.0 0 0 Terbium Oxide 0 2.0 4.0 Solvents 32.20 32.20 32.20Total 100.00 100.00 100.00 Table 10. Non-nitrate Azoles (Comparatives)**Constituents Example Example Example Example Example Example 29 30 31 32 33 34 Thioplast G1 27.55 27.55 27.55 27.55 27.16 27.55 Additives 2.74 2.74 2.74 2.74 2.7 2.74 Fillers 28.84 27.64 28.84 27.64 23.64 27.84 Nano2.30 2.30 2.30 2.30 2.27 2.30 magnesiumoxideMagnesium 4.60 4.60 4.60 4.60 4.54 4.60 oxide(Maglite Y)AMTZ 0.5 1.7 0 0 0 0 DMTZ 0 0 0.5 1.7 0 0 Amino- 0 0 0 0 0 1.5 MercaptanSolvents 33.47 33.47 33.47 33.47 33.00 33.47Total 100.0 100.0 100.0 100.0 100.0 100.0 ** These samples gelled and therefore could not be used for corrosion or swell testing.Table 11. Comparative - Magnesium oxideConstituents Example 35 Thioplast G1 26.95 Additives 2.68 Fillers 30.88 Nano- magnesium oxide 2.25 Magnesium oxide (Maglite Y) 4.5 Solvents 32.74Total 100.00 Table 12. Control Sprayable Polysulfide Sealant Composition Constituents Example 36 Thioplast G1 26.81 Additives 2.67 Fillers 37.95 Solvents 32.57Total 100.00 Table 13. Terbium NitrateConstituents Example 37Thioplast G1 27.16Additives 2.7Fillers 29.83Nano2.27magnesiumoxideMagnesium 4.54oxide (MagliteY)Terbium Nitrate 0.5Solvents 33.0Total 100.0Example B: Class B Polysulfide Sealant Preparation

[0236] The control class B sealant composition shown in Table 14 below (amounts expressed in weight percent) was prepared as follows. Polysulfide resins Thioplast G112 (a mercaptofunctionalized polysulfide sealant commercially available from Nouryon, having a SH content of 15-17% and a molecular weight of 3,900 g / mol to 4,400 g / mol) and Thioplast G12 (a mercaptofunctionalized polysulfide sealant commercially available from Nouryon, having a SH content of 15-17% and a molecular weight of 4,100 g / mol to 4,600 g / mol), adhesion promoters and additives were added to a plastic cup (FlackTek) and agitated in the centrifugal mixer, for 30 sec at 1500 rpm. The fillers were added to the plastic cup and agitated in the centrifugal mixer, per the following sequence 20 sec at 1000 rpm and 30 sec at 1500 rpm. The rest of the additives were then added to the plastic cup and agitated in the centrifugal mixer, for 30 sec at 1500 rpm. The sample was then hand mixed and agitated again in the centrifugal mixer under full vacuum per the following sequence 30 sec at 1000 rpm, 30 sec at 1500 rpm, 30 sec at 1600 rpm. The material was then stored in a nitrogen purged container in a constant temperature and humidity room (77 ± 2 F, 50 ± 5 RH) until use.

[0237] Part B shown in Tables 15-18 below (amounts expressed in weight percent) was prepared as follows. Control Class B Part B and the corrosion inhibitor were added to a plastic cup plastic cup (FlackTek), then agitated in the centrifugal mixer, per the following sequence -30 sec at 1000 rpm, 30 sec at 1500 rpm, 30 sec at 2100 rpm. The material was then stored in a nitrogen purged container in a constant temperature and humidity room (77 ± 2 F, 50 ± 5 RH) until use.

[0238] The polysulfide sealant composition was made as follows. In a container, the sealant part B was combined with Manganese dioxide paste Part A in a 100:10 ratio by weight. Once combined, the material was hand mixed, the container was sealed and then agitated in the centrifugal mixer, per the following sequence -30 sec at 1000 rpm, 30 sec at 1500 rpm, 30 sec at 2100 rpm.

[0239] Substrate was cleaned and deoxidized as described above in Example A.

[0240] The mixed polysulfide sealant was applied to the metal substrate as follows. The sealant was transferred onto the metal substrate from its container after mixing. Subsequently, the material was spread on the surface of the substrate with a metal or plastic scraper until a uniform coating was achieved. The material was then transferred to constant temperature andhumidity room (77 ± 2 F, 50 ± 5 RH) for 14 days until it was fully cured. The sealant was transferred unto the metal substrate from its container after mixing.Table 15. Polysulfide Class B Control Base _Constituents Example 39Polysulfide resins 59.87Adhesion Promoters 9.82Additives 5.27Fillers 18.04Total 93Table 16. Polysulfide Class B Metal OxidesConstituents Example 40 Example 41 Example 42 Control Base 99.5 97.5 97.5 Magnesium Oxide 0.5 0.5 0.5 Lithium Vanadium Oxide 0 2 0 Praseodymium Oxide 0 0 2Total 100 100 100Table 17. Polysulfide Class B Metal NitratesConstituents Example 43 Example 44Control Base 99 99Magnesium Oxide 0.5 0.5Yttrium Nitrate 0.5 0Neodymium Nitrate 0 0.5Total 100 100Table 18. Polysulfide Class B Conjugated CompoundsConstituents Example 45 Example 46Control Base 99.4 99Magnesium Oxide 0.5 0.5Catechol Violet 0.1 0.5Total 100 100Example C: Polythioether Sealant Preparation

[0241] Part B (base) shown in Tables 19 to 25 below (amounts expressed in weight percent) was prepared as follows. PR-2001 Part B-2 (a polythioether sealant composition commercially available from PPG Industries, Inc. and made according to manufacturer’s instruction) and the corrosion inhibitor were added to a plastic cup plastic cup (FlackTek), then agitated in the centrifugal mixer, per the following sequence - 30 sec at 1000 rpm, 30 sec at 1500 rpm, 30 sec at 2100 rpm. The material was then stored in a nitrogen purged container in a constant temperature and humidity room (77 ± 2 F, 50 ± 5 RH) until use.

[0242] The polythioether sealant composition was made as follows. In a container, the sealant part B was combined with PR-2001 Part A accelerator in a 100: 18.5 ratio by weight. Once combined, the material was hand mixed, the container was sealed and then agitated in the centrifugal mixer, per the following sequence -30 sec at 1000 rpm, 30 sec at 1500 rpm, 30 sec at 2100 rpm.

[0243] Substrate was cleaned and deoxidized as described above in Example A.

[0244] The mixed polythioether sealant was applied to the metal substrate as follows. The sealant was transferred unto the metal substrate from its container after mixing.Subsequently, the material was spread on the surface of the substrate with a metal or plastic scraper until a uniform coating was achieved. The material was then transferred to constant temperature and humidity room (77 ± 2 F, 50 ± 5 RH) for 14 days until it was fully cured.Table 19. Polythioether Control _Constituents Example 47PR-2001 B-2 PartB 100Total 100.00Table 20. Polythioether Magnesium OxideConstituents Example 48 Example 49PR-2001 B-2 PartB 98 93Magnesium Oxide 2 7Total 100.00 100.00Table 21, Polythioether Inorganic NitratesConstituents Example 50 Example 51 Example 52 Example 53 Example 54 PR-2001 B-2 Part B 97.85 97.5 97.85 97.5 97.5 Magnesium Oxide 2 2 2 2 2 Neodymium Nitrate 0.15 0.5 0 0 0 Yttrium Nitrate 0 0 0.15 0.5 0 Terbium Nitrate 0 0 0 0 0.5Total 100.00 100.00 100.00 100.00 100.00 Table 22, Poly thioether Organic NitratesConstituents Example 55 Example 56 Example 57 Example 58 PR-2001 B-2 Part B 97.75 96.5 97.75 96.5 Magnesium Oxide 2 2 2 2Econazole Nitrate 0.25 1.5 0 0Isoconazole Nitrate 0 0 0.25 1.5Total 100.00 100.00 100.00 100.00Table 23. Poly thioether Metal OxidesExample Example Example Example Example Example Constituents 59 60 61 62 63 64 PR-2001 B-2 PartB 96 91 96 91 97.5 96 Magnesium Oxide 2 2 2 2 2 2 Praseodynium Oxide(Pr203) 2 7 0 0 0 0 Praseodynium Oxide(Pr6011) 0 0 2 7 0 0 Lithium VanadiumOxide 0 0 0 0 0.5 2 Total100.00 100.00 100.00 100.00 100.00 100.00Table 24, Polythioether Other Metal OxidesConstituents Example 65 Example 66 Example 67 Example 68PR-2001 B-2PartB 96 94 96 94MagnesiumOxide 2 2 2 2TerbiumOxide 2 4 0 0YttriumOxide(Y2O3) 0 0 2 4Total 100.00 100.00 100.00 100.00Table 25. Polythioether Conjugated CompoundsConstituents Example 69 Example 70PR-2001 B-2 Part B 97.975 97.9Magnesium Oxide 2 2Catechol Violet 0.025 0.1Total 100.00 100.00

[0245] Materials used in the Examples are listed in Table 26.Table 26. Material and vendor informationMaterial Vendor City State / Country Catechol Violet Thermofisher Waltham Massachusetts Catechol Violet Molekula Darlington England Catechol Violet Honeywell Charlotte North Carolina Econazole Nitrate TCI America Portland Oregon Econazole Nitrate Sigma St Louis Missouri Econazole Nitrate BOC Sci Shirley New York Econazole Nitrate Molekula Darlington England Isoconazole Nitrate Fisher Scientific Waltham Massachusetts Lithium Vanadium Fisher Scientific Waltham Massachusetts OxideLithium Vanadium Treibacher Althogen Austria OxideLithium Vanadium Prochem Rockford IllinoisOxideLithium Vanadium American Elements Los Angeles California OxideMagnesium oxide Hallstar Company Chicago Illinois Magnesium oxide Nano structured & Houston Texas Amorphous MaterialsInc.Magnesium oxide Martin Marietta Raleigh North Carolina MagnesiaMethylene Blue Sigma St Louis Missouri Neodymium Nitrate Treibacher Althofen Austria Neodymium Nitrate Prochem Rockford Illinois Praseodymium (III) Treibacher Althofen AustriaoxideTerbium Oxide Prochem Rockford IllinoisTerbium Oxide Treibacher Althofen AustriaTerbium Sulfate Prochem Rockford Illinois Tetrafluorozirconium Millipore Corp. St. Louis Missouri Yttrium Nitrate (salt) Prochem Rockford IllinoisYttrium Nitrate (salt) Treibacher Althofen AustriaYttrium Nitrate Prochem Rockford Illinois(solution)Testing MethodsScribing Procedure for Subsequent Filiform and Neutral Salt Spray Testing

[0246] Panels were scribed on a IS400 Gravograph using a scribing bit (Antares: 11 / 64” x 6 1 / 2” Micrograin Carbide Tipped, Half Round, Brass / Aluminum, 0.060” tip, #AC-171-BAL-060). After scribing, loose sealant debris was removed. Panels were then taped so that all edges and the back of the panel were covered.Neutral Salt Spray (NSS) Exposure

[0247] Panels were exposed to 2000 hours of neutral salt spray in accordance with ASTM-B117-19. Following NSS exposure, panels were rated using the scoring system described in Table 27.Table 27. Rating ScaleDescription ScoreScribe TarnishingScribe Line > 98% Shiny 0Scribe Line > 75% Shiny 5Scribe Line > 50% Shiny 10Scribe Line > 25% Shiny 15Scribe Line Darkened 20Blister SizeNo Creepage 0About 0.00mm - 0.4mm 5About 0.5mm - 0.8mm 10About 0.9mm - 1.6mm 15About 1.7mm - 3.2mm 20About 3.3mm - 5.0mm 25About 5.1mm - 9.5mm30

[0248] Data are reported in FIGS. 1-8 (sprayable polysulfide sealant compositions 1-38), FIG. 21 (polysulfide sealant composition 39-46), and FIGS. 22-25 (polythioether sealant compositions 47-70).

[0249] As shown in FIGS. 1 and 2, a sprayable (Class F) poly sulfide sealant formed from a sprayable sealant composition including both magnesium oxide and lithium vanadium oxide (Examples 4-6) resulted in improved corrosion resistance. Specifically, as shown in FIG. 1, 2024-T3 substrates treated with Examples 4-6 had a NSS Corrosion Rating score lower than control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (polysulfide with chromium). Similarly, as shown in FIG. 2, 7075-T6 substrates treated with Examples 4-6 had a NSS Corrosion Rating score lower than control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor) and lower than comparative Example 35 (polysulfide with magnesium oxide), while the NSS Corrosion Rating score of Examples 4-6 was comparable to that of Example 38 (polysulfide with chromium). Notably, both 2024-T3 and 7075-T6 treated with a sprayable polysulfide sealant composition including magnesium and yttrium oxide (Examples 23 and 24) or magnesium and terbium oxide (Examples 27 and 28) had NSS Corrosion Rating scores higher than control Example 36.

[0250] As shown in FIGS. 3 and 4, a polysulfide sealant formed from a sprayable composition including both magnesium oxide and neodymium nitrate (Example 1) or both magnesium oxide and terbium nitrate (Example 37) resulted in improved corrosion resistance. Specifically, as shown in FIG. 3 and FIG. 4, 2024- T3 and 7075-T6 substrates, respectively, treated with Examples 1 and 37 had a NSS Corrosion Rating score lower than control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor) and comparative Example 35 (polysulfide with magnesium oxide), while performing similarly to chromium-containing comparative Example 38 (polysulfide with chromium). Notably, both 2024-T3 and 7075-T6 substrates treated with a sprayable polysulfide sealant composition including magnesium and yttrium nitrate (Examples 8-10) or magnesium oxide and neodymium oxide (Examples 2-4) had NSS Corrosion Rating scores higher than control Example 36.

[0251] As shown in FIGS. 5 and 6, a polysulfide sealant formed from a sprayable composition including both magnesium oxide and either econazole nitrate (Examples 17-19) or isoconazole nitrate (Examples 20-22) resulted in improved corrosion resistance. Specifically, as shown in FIG. 5 and FIG. 6, 2024-T3 and 7075-T6 substrates, respectively, treated with Examples 17-22 had a NSS Corrosion Rating score lower than control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor) and comparative Example 35 (polysulfide with magnesium oxide), while performing similarly to chromium-containing comparative Example 38 (polysulfide with chromium).

[0252] As shown in FIG. 7, a polysulfide sealant formed from a sprayable composition including both magnesium oxide and catechol violet (Examples 11-13) resulted in improved corrosion resistance. Specifically, 2024-T3 substrate treated with Example 11 had a NSS Corrosion Rating score lower than control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (polysulfide with chromium).

[0253] As shown in FIG. 21, a Class B polysulfide sealant formed from a composition including both magnesium oxide and catechol violet (Examples 45 and 46), lithium vanadium oxide (Example 41), neodymium nitrate (Example 44), or praseodymium oxide (Example 42) had NSS Corrosion Rating score lower than or comparable to comparative Example 40 (Class B polysulfide with magnesium oxide).

[0254] As shown in FIG. 22, a polythioether sealant formed from a composition including both magnesium oxide and lithium vanadium oxide (Examples 63 and 64), praseodymium oxide (Examples 59-62), terbium oxide (Examples 65 and 66), or yttrium oxide (Examples 48 and 49) had NSS Corrosion Rating scores lower than or comparable to comparative Examples 48 and 49 (magnesium only) or control (polythioether without magnesium oxide or corrosion inhibitor).

[0255] As shown in FIG. 23, a polythioether sealant formed from a composition including both magnesium oxide and neodymium nitrate (Examples 50 and 51), terbium nitrate (Example 54), Yttrium nitrate (Examples 52 and 53) had NSS Corrosion Rating scores lower than or comparable to comparative Examples 48 and 49 (magnesium only) or control (polythioether without magnesium oxide or corrosion inhibitor).

[0256] As shown in FIG. 24, a polythioether sealant formed from a composition including both magnesium oxide and econazole nitrate (Examples 55 and 56) or isoconazole nitrate (Examples 57 and 58) had NSS Corrosion Rating scores lower than or comparable to comparative Examples 48 and 49 (magnesium only) or control (polythioether without magnesium oxide or corrosion inhibitor).

[0257] As shown in FIG. 25, a polythioether sealant formed from a composition including both magnesium oxide and catechol violet (Examples 69 and 70) had NSS Corrosion Rating scores comparable to comparative Examples 48 and 49 (magnesium only) or control (polythioether without magnesium oxide or corrosion inhibitor).Filiform testing

[0258] Filiform testing was performed in accordance with MIL-PRF-23377K.

[0259] The test panels were placed vertically in a desiccator containing approximately one inch of 12 Normal (N) HC1 for 1 hour at room temperature. Within 5 minutes of removal from the desiccator, the test panels were placed in a humidity cabinet maintained at 40 ±2° C (104 ±3° F) and relative humidity of 80 ±5 percent for 1,000 hours.

[0260] Following testing, the filament lengths were measured. Values reported in FIGS.9-12 are an average of 3 measurements per sample (in mm).

[0261] As shown in FIG. 9, a sprayable polysulfide sealant composition including both magnesium oxide and either lithium vanadium oxide (Examples 4-6), yttrium oxide (Examples 23 and 24), or terbium oxide (Examples 27 and 28) resulted in improved corrosion resistance asdemonstrated by a filament length less than that of control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (polysulfide with chromium).

[0262] As shown in FIG. 10, a sprayable polysulfide sealant composition including both magnesium oxide and yttrium nitrate (Examples 8-10), terbium nitrate (Example 37), or neodymium nitrate (Examples 1-4) resulted in improved corrosion resistance as demonstrated by a filament length less than that of control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (polysulfide with chromium).

[0263] As shown in FIG. 11, a sprayable polysulfide sealant composition including both magnesium oxide and isoconazole nitrate (Examples 20-22) resulted in improved corrosion resistance as demonstrated by a filament length less than that of control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (poly sulfide with chromium).

[0264] As shown in FIG. 12, a sprayable polysulfide sealant composition including both magnesium oxide and catechol violet (Examples 11-13) resulted in improved corrosion resistance as demonstrated by a filament length less than that of control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (poly sulfide with chromium).Volume Swell Test Method

[0265] Volume swell was measured following exposure of substrates having sealant on the surface to deionized water (77 ± 5ºF for 8 hours) and following exposure of substrates to deionized water at 60°C in accordance with 7.5 in AS5127 Rev. 1D. Three specimens measuring 1 inch x 1 inch were cut from a sheet of fully cured sealing compound. The % increase in volume of the sealant of experimental sealants relative to the volume of the sample before immersion is reported in FIG. 13-20.

[0266] As shown in FIGS. 13 and 14, sealants containing magnesium oxide and low levels of lithium vanadium oxide-controlled swell at STD and at all levels tested controlled swell at 60°C compared to control Example 36 (polysulfide without magnesium oxide or corrosioninhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (poly sulfide with chromium). The low swell in combination with the corrosion performance achieved under both NSS and filiform testing with a sprayable polysulfide sealant containing both magnesium oxide and lithium vanadium oxide (discussed above) was a surprising and unexpected result.

[0267] As shown in FIG. 15, sprayable sealants containing magnesium oxide and yttrium nitrate (Examples 8-10) had swell at STD lower than swell seen in control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor) and comparative Example 35 (poly sulfide with magnesium oxide), and comparable to that seen in chromium-containing comparative Example 38 (polysulfide with chromium). The low swell in combination with the corrosion performance achieved under filiform testing with a sprayable polysulfide sealant containing both magnesium oxide and yttrium nitrate (discussed above) was a surprising and unexpected result.

[0268] As shown in FIG. 16, sprayable sealants containing magnesium oxide and yttrium nitrate (Examples 8-10), neodymium nitrate (Examples 1-4), or terbium nitrate (Example 37) had swell at 60°C lower than swell seen in control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (polysulfide with chromium). The low swell in combination with the corrosion performance discussed above was a surprising and unexpected result.

[0269] As shown in FIGS. 17 and 18, sprayable sealants containing magnesium oxide and isocanazole nitrate (Examples 20-22) or econazole nitrate (Examples 17-19) had swell at STD or 60°C comparable to or less than swell seen in control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containing comparative Example 38 (polysulfide with chromium). The low swell in combination with the corrosion performance discussed above was a surprising and unexpected result.

[0270] As shown in FIGS. 19 and 20, sprayable sealants containing magnesium oxide and catechol violate (Examples 11-13) had swell at STD or 60°C comparable to or less than swell seen in control Example 36 (polysulfide without magnesium oxide or corrosion inhibitor), comparative Example 35 (polysulfide with magnesium oxide), and chromium-containingcomparative Example 38 (polysulfide with chromium). The low swell in combination with the corrosion performance discussed above was a surprising and unexpected result.

[0271] Whereas particular features of the present disclosure have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the coating composition, coating, and methods disclosed herein may be made without departing from the scope in the appended claims.

Claims

We claim:

1. A sealant composition comprising:a film-forming binder comprising a base comprising a resin comprising a sulfur-containing compound;magnesium oxide; anda second corrosion inhibitor in addition to the magnesium oxide.

2. The sealant composition of claim 1, wherein the composition, in a cured state, forms a sealant that is a barrier to movement of vapor and / or liquid from a first side of the sealant to a second side of the sealant.

3. The sealant composition of claim 1 or claim 2, wherein the second corrosion inhibitor comprises a metal oxide, a mixed metal oxide, a nitrate, and / or a conjugated compound.

4. The sealant composition of any preceding claim, wherein the second corrosion inhibitor comprises a metal oxide and / or a mixed metal oxide comprising an alkali metal, a lanthanide metal, and / or a transition metal.

5. The sealant composition of any of claims 1 to 3, wherein the second corrosion inhibitor comprises a metal nitrate.

6. The sealant composition of claim 5, wherein the metal nitrate comprises a rare earth metal, a lanthanide metal, and / or a transition metal.

7. The sealant composition of any preceding claim, wherein the second corrosion inhibitor comprises lithium, vanadium, praseodymium, terbium, yttrium, and / or neodymium.

8. The sealant composition of any of claims 1 to 3, wherein the second corrosion inhibitor comprises an organic nitrate.

9. The sealant composition of claim 8, wherein the second corrosion inhibitor comprises an azole.

10. The sealant composition of any of claims 1 to 3, wherein the conjugated compound comprises catechol violet and / or xylenol orange.

11. The sealant composition of any preceding claim, comprising:(a) the film-forming resin binder in an amount of 80 percent by weight to 99.5 percent by weight;(b) the magnesium oxide in an amount of 0.1 percent by weight to 10 percent by weight;(c) the second corrosion inhibitor in an amount of 0.05 percent by weight to 3 percent by weight;(d) the second corrosion inhibitor in an amount of 0.1 percent by weight to 10 percent by weight; and / or(e) the second corrosion inhibitor in an amount of 0.01 percent by weight to 1 percent by weight;wherein percent by weight is based on total weight of the composition.

12. The sealant composition of any preceding claim, wherein the sulfur-containing compound comprises a polysulfide and / or a polythioether.

13. The sealant composition of any preceding claim, further comprising an accelerator and / or a solvent.

14. The sealant composition of claim 13, wherein the curing agent comprises a second metal oxide in addition to the second corrosion inhibitor, an organic peroxide, an inorganic peroxide, and / or an epoxy-containing compound.

15. The sealant composition of claim 14, wherein:(a) the second metal oxide comprises manganese dioxide; and / or(b) wherein the epoxy-containing compound comprises a diepoxide, a triepoxide, and / or a novolac.

16. The sealant composition of any preceding claim, wherein the magnesium oxide comprises nano-sized magnesium oxide and / or micron-sized magnesium oxide.

17. The sealant composition of any preceding claim, wherein the composition is substantially free of hexavalent chromium and / or a fluoro-containing polymer.

18. The sealant composition of any preceding claim, wherein the base has a viscosity of:(a) 10 P to 150 P measured using a viscometer with a No. 4 spindle at a speed of 10 RPM under ambient condition;(b) 1,000 P to 12,000 P measured using a viscometer with a No. 7 spindle at a speed of 2 RPM under ambient condition;(c) 1,000 P to 12,000 P measured using a viscometer with a No. 6 spindle at a speed of 10 RPM under ambient condition; or(d) 100 P to 600 P measured using a viscometer with a No. 6 spindle at a speed of 10 RPM under ambient condition.

19. A sealant formed from the sealant composition of any preceding claim.

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