MULTILAYER SYSTEMS AND METHODS FOR DEVELOPING MULTILAYER SYSTEMS

Abstract

Methods for manufacturing multilayer systems comprising a sealing layer by extruding a co-reactive sealing composition are disclosed; the methods can be used to manufacture multilayer systems in which the individual layers have different curing properties; the individual layers can also have a non-homogeneous concentration of one or more components within a layer; the multilayer systems can be made by three-dimensional printing, which facilitates the use of a wide range of co-reactive compositions.

Description

MULTILAYER SYSTEMS AND METHODS FOR MAKING MULTILAYER SYSTEMS This application claims benefit under 35 U.S.C. § 119(e) of US Provisional Application No. 62 / 803,727, filed February 11, 2019, which is incorporated by reference in its entirety. FIELD OF THE INVENTION The disclosure relates to methods for making multilayer systems comprising at least one sealant layer, multilayer systems made using the methods, and uses of multilayer systems. Each individual layer of a multilayer system can be designed to have a desired property. The individual layers of a multilayer system may also have an inhomogeneous concentration of one or more constituents within an individual layer. Multilayer systems can be made through the use of extrusion methods, such as three-dimensional printing. Multi-layer systems can be used as sealers. BACKGROUND OF THE INVENTION Sealers are generally provided as homogeneous compositions that are applied to a substrate. In one part systems, the sealant is applied to a substrate and curing is initiated by the application of energy, such as by exposure to ultraviolet radiation. In two part systems, the individual parts are combined and mixed before they are used and the curing reaction proceeds when the reactive components are combined. Performance attributes for cured sealants may include, for example, one or more of chemical resistance, low temperature flexibility, hydrolytic stability, high temperature strength, tensile strength, % elongation, substrate adhesion, adhesion to one coat. Adjacent, Tack Free Time, Time to Shore 10A Hardness, Electrical Conductivity, EMI / RFI Shielding, Static Dissipation, Thermal Conductivity, Low Density, Corrosion Resistance, Surface Hardness, Flame Retardancy, UV Resistance, and Strength to rain erosion. Multilayer systems having at least one sealant and methods of making sealant systems having one or more of these attributes are desirable. I ΗΓ1 n / L7n7 / q / YIAI BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, methods of making a multi-layer system comprising two or more layers, wherein one or more of the layers comprise a sealant layer, comprising: (a) mixing a first component and a second component to form a coreactive sealant composition, wherein the coreactive sealant composition comprises a first reactive compound and a second reactive compound; and the first reactive compound reacts with the second reactive compound; (b) extruding the coreactive sealant composition to form an extrudate; and (c) depositing the extrudate to form the sealant layer. BRIEF DESCRIPTION OF THE DRAWINGS The drawings described herein are for illustrative purposes only. The drawings are not intended to limit the scope of the present disclosure. Figures 1A to ID show cross-sectional views of multilayer systems comprising at least one sealant layer provided by the present disclosure. Figure 2A shows cross-sectional views of a layer of a multilayer system provided by the present disclosure in which the concentration of a constituent varies within the thickness of the layer. Figure 2B shows cross-sectional views of a layer of a multilayer system provided by the present disclosure in which the concentration of a constituent varies within a lateral dimension of the layer. Figure 3 shows a cross-sectional view of a multilayer system provided by the present disclosure that includes a coating. Figure 4 shows a cross-sectional view of an example of a co-extruder. DETAILED DESCRIPTION OF THE INVENTION For purposes of the following detailed description, it is to be understood that the embodiments provided by the present disclosure may assume various variations and alternative step sequences, except where otherwise expressly specified. Furthermore, apart from any working examples, or where otherwise indicated, it is to be understood that all numbers expressing, for example, quantities of ingredients used in the specification and claims are in all cases modified by the expression I 1 Π / I 7Π7 / 3 / ΥΙΛΙ around. Accordingly, unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending on the properties desired to be obtained with the present invention. At a minimum, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be interpreted at least in light of the reported number of significant digits and by applying customary rounding techniques. Although the parameters and numerical ranges that establish the broad scope of the invention are approximations, the numerical values ​​stated in the specific examples are reported as accurately as possible. However, any numerical value inherently contains certain errors that necessarily result from the standard variation found in their respective test measurements. Furthermore, it is to be understood that any numerical range listed herein is intended to include all subranges included therein. For example, a range from 1 to 10 is intended to include all subranges between (and inclusive of) the mentioned minimum value of 1 and the mentioned maximum value of 10, that is, it has a minimum value equal to or greater than 1 and a maximum value equal to 1. or less than 10. "Alcanarene" refers to a hydrocarbon group having one or more aryl and / or areniyl groups and one or more alkyl and / or alkandiyl groups, where aryl, areniyl, alkyl and alkandiyl are defined herein. Each aryl and / or areniyl group can be Ce-12, Ce-io, phenyl or benzendiyl. Each alkyl and / or alkandiyl group can be Ci-β, Ci-4, C1-3, methyl, methandiyl, ethyl or ethane-1,2-diyl. An alkanarene group can be C4-18 alkanarene, C4-16 alkanarene, C4-12 alkanarene, C4-8 alkanarene, C6-12 alkanarene, Ce-ίο alkanarene or Ce-9 alkanarene. Examples of alkanarene groups include diphenylmethane. Alcanarendiyl refers to a diradical of an alcanarene group. An alkanerendiyl group can be Ce-is alkanerendiyl, Ce-i6alkanerdiyl, C6-12 alkanerendiyl, Ce-s alkanerendiyl, C6-12 alkanerendiyl, Ce-io alkanerendiyl or Ce-9 alkanerendiyl. Examples of alkanerendiyl groups include diphenyl methane-4,4'-dyl. "Alkanecycloalkane" refers to a saturated hydrocarbon group having one or more cycloalkyl and / or cycloalkandiyl groups and one or more alkyl and / or alkandiyl groups, where cycloalkyl, cycloalkandiyl, alkyl and alkandiyl are defined herein. Each cycloalkyl and / or cycloalkandiyl group can be C3-6, C5-6, cyclohexyl or cyclohexandyl. Each alkyl and / or alkandiyl group can be C1-6, C1-4, C1-3, methyl, methandiyl, ethyl or ethane-1,2-diyl. An alkanecycloalkane group can be Ce-18 alkanecycloalkane, Ce-i6 alkanecycloalkane, C6-12 alkanecycloalkane, Ce-s alkanecycloalkane, C6-12 alkanecycloalkane, Ce-io alkanecycloalkane or Ce-9 alkanecycloalkane. Group Examples I br1 n / 17Π7 / 3 / ΥΙΛΙ alkancycloalkane include 1,1,3,3-tetramethylcyclohexane and cyclohexylmethane. Alkancycloalkandiyl refers to a diradical of an alkanecycloalkane group. An alkanecycloalkandiyl group can be C4-18 alkanecycloalkandiyl, C4-16 alkanecycloalkandiyl, C4-12 alkanecycloalkandiyl, C4-8 alkanecycloalkandiyl, C6-12 alkanecycloalkandiyl, Ce-io alkanecycloalkandiyl or Ce-9 alkanecycloalkandiyl. Examples of alkancycloalkandiyl groups include 1,1,3,3-tetramethylcyclohexan-1,5-d¡¡l and cyclohexylmethane-4,4'-d¡¡l. Alkandiyl refers to a diradical of a saturated straight or branched chain acyclic hydrocarbon group having, for example, 1 to 18 carbon atoms (Ci-is), 1 to 14 carbon atoms (C1-14), of 1 to 6 carbon atoms (Ci-e), 1 to 4 carbon atoms (C1-4) or 1 to 3 hydrocarbon atoms (C1-3). It will be appreciated that a branched alkandiyl has a minimum of three carbon atoms. An alkandiyl can be C2-14 alkandiyl, C2-10 alkandiyl, C2-8 alkandiyl, C2-6 alkandiyl, C2-4 alkandiyl or C2-3 alkandiyl. Examples of alkandiyl groups include methane-diyl (-CH2-), ethane-1,2-diyl (-CH2CH2-), propan-1,3-diyl, and iso-propan-1,2-diyl (for example, - CH2CH2CH2- and -CH(CH3)CH2-), butan-1,4-diyl (-CH2CH2CH2CH2-), pentan-1,5-diyl (-CH2CH2CH2CH2CH2-), hexan-1,6-diyl (-CH2CH2CH2CH2CH2CH2-) , heptan-1,7-diyl, octan-1,8-diyl, nonan-1,9-diyl, decane-1,10-diyl and dodecane-1,12-diyl. Alkandiyl groups can include single, double, and / or triple bonds between carbon atoms. Alkenyl group refers to the structure -CR=C(R)2, where the alkenyl group is a group and is attached to a larger molecule. In such embodiments, each R can independently comprise, for example, hydrogen and C1-3 alkyl. Each R can be hydrogen and an alkenyl group can have the structure -CH=CH2. Alkoxy refers to a -OR group where R is alkyl as defined herein. Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, and n-butoxy. An alkoxy group can be C1-8 alkoxy, Ci-β alkoxy, Ci-4 alkoxy or C1-3 alkoxy. "Alkyl" refers to a monoradical of a saturated straight or branched chain acyclic hydrocarbon group having, for example, 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon atoms or 1 to 3 carbon atoms. It will be appreciated that a branched alkyl has a minimum of three carbon atoms. An alkyl group can be C1-6 alkyl, C1-4 alkyl, and C1-3 alkyl. Examples of alkyl groups include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-hexyl, n-decyl, and tetradecyl. An alkyl group is Ci-β alkyl, C1-4 alkyl, and C1-3 alkyl. Arendiyl refers to a diradical monocyclic or polycyclic aromatic group. Examples of areniyl groups include benzen-diyl and naphthalene-diyl. An areniyl group can be Ce12arendiyl, Ce-ioarendiyl, Ce-9arendiyl or benzenediyl. Catalyst refers to a substance that increases the rate of a reaction without I br1 η / I 7Π7 / 3 / ΥΙΛΙ modify the overall standard Gibbs energy change in the reaction. When referring to a chemical group defined, for example, by a number of carbon atoms, the chemical group is intended to include all subranges of carbon atoms, as well as a specific number of carbon atoms. For example, a C2-10 alkandiyl includes a C2-4 alkandiyl, C5-7 alkandiyl and other subranges, a C2-alkandiyl, a Ce alkandiyl, and alkandiyls having other specific numbers of carbon atoms from 2 to 10. Coating refers to a thin film, such as a film having an applied and dry thickness of less than 500 pm, less than 100 pm, or less than 50 pm. A coating can have a thickness less than that of a layer that forms a multilayer system. "Component" refers to a composition in which the constituents of the component are not coreactive until combined and mixed with another component to form a coreactive composition. A reactive functional compound refers to a compound having a functional group capable of reacting with a complementary reactive functional group of another compound. The reactive functional group can be attached to the ends of the compound, to the main chain of the compound. Constituent refers to an organic compound or an inorganic compound. A composition and a component can comprise one or more constituents. Examples of constituents include prepolymers, monomers, polyfunctional agents, and additives as disclosed herein. A core of an agent with B(-V)z polyfunctionality refers to the B portion. A nucleus of a compound or polymer refers to the segment between reactive groups. For example, the nucleus of a HS-R-SH polythiol is -R-. A compound core or prepolymer may also be referred to as a compound backbone or prepolymer backbone. A nucleus of an agent with polyfunctionality may be an atom or structure such as a cycloalkane, substituted cycloalkane, heterocycloalkane, substituted heterocycloalkane, arene, substituted arene, heteroarene, or substituted heteroarene, to which moieties having a reactive functional group are attached. . Coreactive composition refers to a composition comprising at least two reactive compounds capable of reacting with each other. A coreactive composition refers to a composition comprising two or more coreactive compounds capable of reacting at a temperature, for example, less than 50°C, less than 40°C, less than 30°C or less than 20°C. The reaction between the two or more reactive compounds can be initiated by combining and mixing the two or more coreactive compounds, by adding a catalyst to a coreactive composition comprising two or more coreactive compounds, and / or by activating a polymerization initiator in a I 1 η / I 7Π7 / 3 / ΥΙΛΙ coreactive composition comprising the two or more coreactive compounds. A coreactive composition can be formed, for example, by combining and mixing a first reactive component comprising a first reactive compound with a second reactive component comprising a second reactive compound, wherein the first reactive compound can react with the second reactive compound. A coreactive composition can be a thermosetting composition and when cured forms a thermoset. A coreactive non-sealing composition refers to a coreactive composition that is not formulated as a sealer. Although a cured coreactive non-sealing composition may exhibit some properties of a sealer, the primary function of a cured coreactive non-sealing composition is not to act as a sealer. A coreactive sealer composition refers to a coreactive composition formulated as a sealer. Coreactive three-dimensional printing refers to a method as disclosed herein in which a coreactive composition is extruded through a die or extrusion in successive layers to form one part. "Cycloalkandiyl" refers to a diradical saturated monocyclic or polycyclic hydrocarbon group. A cycloalkandiyl group can be C3-12 cycloalkandiyl, C3-8 cycloalkandiyl, C3-6 cycloalkandiyl or C5-6 cycloalkandiyl. Examples of cycloalkandiyl groups include cyclohexane-1,4-diyl, cyclohexane-1,3-diyl and cyclohexane-1,2-diyl. "Cycloalkyl" refers to a saturated monocyclic or polycyclic hydrocarbon monoradical group. A cycloalkyl group can be C3-12 cycloalkyl, C3-8 cycloalkyl, C3-6 cycloalkyl or C5-6 cycloalkyl. "Heteroalkandiyl" refers to an alkandiyl group in which one or more of the carbon atoms are replaced by a heteroatom, such as N, O, S, or P. In a heteroalkandiyl, the one or more heteroatoms may comprise N or O. "Cure time" refers to the duration from the initiation of the curing reaction of a coreactive composition, for example, by combining and mixing coreactive components to form the coreactive composition and / or by exposing a coreactive composition to actinic radiation, until a layer prepared with the coreactive composition exhibits a hardness of Shore 30A under conditions of 25°C and 50% RH. In the case of an actinic radiation curable composition, cure time refers to the duration from the first exposure of the coreactive composition to actinic radiation to the time when a layer prepared with the exposed coreactive composition exhibits a hardness of Shore 30A. under conditions of 25°C and 50% RH. A hyphen not between two letters or symbols is used to indicate a point of attachment for a substituent or between two atoms. For example, -CONH2 is attached through the I 1 n / 17Π7 / 3 / ΥΙΛΙ carbon atom. Derived from, as in a portion derived from a compound, or the like refer to a portion generated upon reaction of a parent compound with a reagent. For example, a bis(alkenyl) compound CH2=CH-R-CH=CH2 can react with another compound such as a compound having thiol groups to produce the moiety -(CH2)2-R-(CH2)z-, derived from the reaction of alkenyl groups with thiol groups. As another example, in the case of a parent diisocyanate having the structure O=C=N-R-N=C=O, a portion derived from the diisocyanate has the structure -C(O)-NH-R-NH-C(O)- . "Derived from the reaction of -R with a thiol" refers to an -R- moiety that results from the reaction of a thiol group with a moiety comprising a group reactive with a thiol group. For example, a group R- can comprise CH2=CH-CH2-O-, where the alkenyl group CH2=CH- is reactive with a thiol group -SH. Upon reaction with a thiol group, the -R- moiety is CH2-CH2-CH2-O-. Extruded refers to a coreactive composition that has been extruded through an extrusion die or flask. Coextruded refers to two or more coreactive compositions that have been simultaneously extruded through an extrusion die or flask. Formed from or prepared from indicates, for example, comprising claiming the open language. As such, a composition formed from or prepared from a list of named components is intended to be a composition comprising at least the named components or the reaction product of at least the named components and may further comprise other unmentioned components used to form or prepare the composition. Fracture energy is determined in accordance with ASTM D7313. The glass transition temperature Tg is determined by dynamic mechanical analysis (DMA) with a TA Instruments Q800 apparatus with a frequency of 1 Hz, an amplitude of 20 microns, and a temperature rise of -80°C to 25°C, where Tgse identify δ as the peak of the tan curve. "Heterocycloalkandiyl" refers to a cycloalkandiyl group in which one or more of the carbon atoms are replaced by a heteroatom, such as N, O, S, or P. In a heterocycloalkandiyl, the one or more heteroatoms may comprise N or O. A monomer refers to a low molecular weight compound and may have a molecular weight, for example, less than 1,000 Da, less than 800 Da, less than 600 Da, less than 500 Da, less than 400 Da or less than 300 Da. A monomer may have a molecular weight, for example, from 100 Da to 1,000 Da, from 100 Da to 800 Da, from 100 Da to 600 Da, from 150 Da to 550 Da, or from 200 Da to 500 Da. A monomer can have a molecular weight greater than 100 Da, greater than I 1 η / I 7Π7 / 3 / ΥΙΛΙ 200 Da, greater than 300 Da, greater than 400 Da, greater than 500 Da, greater than 600 Da or greater than 800 Da. A monomer can have a reactive functionality of two or more, for example, 2 to 6, 2 to 5, or 2 to 4. A monomer can have a functionality of 2, 3, 4, 5, 6, or a combination of these. any of the above. A monomer can have an average reactive functionality, for example, 2 to 6, 2 to 5, 2 to 4, 2 to 3, 2.1 to 2.8, or 2.2 to 2.6. Reactive functionality refers to the number of reactive functional groups per molecule. A combination of molecules having a different number of reactive functional groups may have a non-integer average number of reactive functional groups. A polyalkenyl refers to a compound that has at least two alkenyl groups. The at least two alkenyl groups may be alkenyl groups and such polyalkenyls may be referred to as alkenyl-terminated compounds. The alkenyl groups can also be pendant alkenyl groups. A polyalkenyl can be a dialkenyl, which has two alkenyl groups. A polyalkenyl can have more than two alkenyl groups, such as three to six alkenyl groups. A polyalkenyl may comprise a single type of polyalkenyl, it may be a combination of polyalkenyls having the same alkenyl functionality, or it may be a combination of polyalkenyls having different alkenyl functionalities. An agent with polyfunctionality can have the structure: B(-V)z where B is the nucleus of the agent with polyfunctionality, each V is a moiety terminated by a reactive functional group such as a thiol group, alkenyl group, epoxy group, isocyanate group, or Michael acceptor group and z is an integer from 3 to 6, such as 3, 4, 5, or 6. In agents with polyfunctionality, each -V can have the structure, for example, -R-SH or -RCH=CH2, where R can be , for example, C2-10 alkandiyl, C2-10 heteroalkandiyl, substituted C2-10 alkandiyl or substituted C2-10 heteroalkandiyl. When the V moiety reacts with another compound, the -V1- moiety arises and is said to be derived from the reaction with the other compound. For example, when V is -R-CH=CH2 and reacts, for example, with a thiol group, the V1 moiety is -R-CH2-CH2y is derived from the reaction. "Polymerization initiator" refers to a compound capable of initiating a polymerization reaction after activation of the polymerization initiator. A polymerization initiator can be activated, for example, upon exposure to actinic radiation, heat, and / or shear forces. Prepolymer refers to homopolymers and copolymers. In the case of thiol-terminated prepolymers, molecular weights are number average molecular weights Mn as determined by end group analysis with iodine titration. In the case of non-thiol terminated prepolymers, the number average molecular weights are determined I 1 n / 17Π7 / 3 / ΥΙΛΙ by gel permeation chromatography with polystyrene standards. A prepolymer comprises a backbone and reactive groups capable of reacting with another compound such as a curing agent or crosslinker to form a cured polymer. A prepolymer includes multiple repeating subunits linked together that may be the same or different. The multiple repeating subunits make up the backbone of the prepolymer. Backbone of a polymer refers to a segment between the reactive functional groups of the prepolymer. A prepolymer backbone generally includes repeating subunits. For example, the backbone of a polythiol having the structure HS(R)n-SH is -(R)n-. "Reaction product" means chemical reaction products of at least the mentioned reactants and may include partial reaction products, as well as complete reaction products and other reaction products that are present in a minor amount. For example, a prepolymer comprising the reaction product of the reactants refers to a prepolymer or a combination of prepolymers that are the reaction product of at least the aforementioned reactants. Furthermore, the reagents may comprise additional reagents. "Reactive compound" refers to a compound that reacts with another compound. A reactive compound can comprise one or more functional groups that are reactive with functional groups of another compound. Sealer coat refers to a coating that when cured functions as a sealer. A sealant layer can be prepared from a coreactive sealant composition. Shore A hardness is measured using a Type A durometer in accordance with ASTM D2240. The specific gravity and density of the particles are determined in accordance with ISO 787-11. A sulfur-containing prepolymer refers to a prepolymer in which the backbone comprises one or more thioether groups -Sn-, where n can be, for example, from 1 to 6, in the backbone of the prepolymer. Prepolymers containing only thiol or other sulfur-containing groups either as groups or as pendant groups of the prepolymer are not encompassed by sulfur-containing prepolymers. The prepolymer backbone refers to the part of the prepolymer that has repeating segments. Therefore, a prepolymer having the structure HS-R-R(-CH2-SH)-[-R-(CH2)2-S(O)2-(CH2)-S(O)2]n-CH=CH2 , where each R is a moiety that does not contain a sulfur atom in the main chain of the prepolymer, is not encompassed by sulfur-containing prepolymer. A prepolymer having the structure HS-R-R(CH2-SH)-[-R-(CH2)2-S(O)2-(CH2)-S(O)2]-CH=CH2, where at least one R is a moiety containing a sulfur atom, such as a thioether group, is encompassed by prepolymer that I 1 Π / I 7Π7 / 3 / ΥΙΛΙ contains sulfur. Examples of sulfur-containing prepolymers include polythioether prepolymers, polysulfide prepolymers, sulfur-containing polyformal prepolymers, and monosulfide prepolymers. "Substituted" refers to a group in which each of one or more hydrogen atoms is independently replaced with the same or different substituents. A substituent may comprise, for example, halogen, -S(O)2OH, -S(O)2, -SH, -SR, where R is Ci-io alkyl, -COOH, -NO2, -NR2, where each R independently comprises hydrogen and C1-10 alkyl, -CN, =0, C1-10 alkyl, -CF3, -OH, phenyl, C2-10 heteroalkyl, C5-6 heteroaryl, C1-10 alkoxy or COR where R is C1-10 I rent. A substituent can be, for example, -OH, -NH2 or C1-3alkyl. Tack-free time refers to the duration from the time the curing reaction of a coreactive composition is initiated, for example, by mixing two coreactive components or by exposing a coreactive composition to energy, such as UV radiation, to the time at which the coreactive composition is no longer tack free. The tack-free property is determined by applying a polyethylene sheet to the surface of the coating with hand pressure and observing if the sealant adheres to the surface of the polyethylene sheet, where the coating is considered tack-free if the polyethylene foil is easily separated from the coating. In the case of an actinic radiation curable coreactive composition, tack-free time refers to the time from exposure of the coreactive composition to actinic radiation to the time that a layer prepared with the coreactive composition is no longer tack-free. Tensile strength and elongation are measured in accordance with AMS 3279. Thermoset refers to a cured thermosetting polymer composition. Thermosetting composition refers to a composition comprising coreactive compounds that irreversibly change to an infusible and insoluble polymer network upon curing. Curing is the chemical process of converting a prepolymer and curing agents to a higher molecular weight polymer and then to a polymer network. The result of curing in chemical reactions that create extensive crosslinking between the A-polymer network is a highly branched structure in which, in essence, each constitutional unit is connected to every other constitutional unit and to the macroscopic phase boundary via many pathways. through the structure, where the number of such pathways increases with the average number of constitutional units involved; pathways should be coextensive on average with the structure. Reference is now made to certain compounds, compositions, and methods of the present invention. The compounds, compositions, and methods disclosed are not intended to limit the claims. Rather, the claims are intended to cover all alternatives, modifications, and equivalents. I 1 n / L7R7 / 3 / YIAI Methods of making a multi-coat system comprising two or more coats, wherein one or more of the coats comprise a sealer coat, comprise: (a) mixing a first component and a second component to form a coreactive sealer composition, wherein the coreactive sealant composition comprises a first reactive compound and a second reactive compound; and the first reactive compound reacts with the second reactive compound; (b) extruding the coreactive sealant composition to form an extrudate; and (c) depositing the extrudate to form the sealant layer. A sealant composition refers to a material that can form, when cured, a sealant capable of withstanding at least one of an atmospheric condition, such as humidity and / or temperature, and at least partially block the transmission of materials, such as water, solvent, fuel, hydraulic fluid and other liquids and gases. A sealant may exhibit chemical resistance, such as resistance to fuels, hydraulic fluids, solvents, greases, lubricants, salt mists, gases, oils, and / or cleaning fluids. A chemically resistant material may exhibit, for example, a % swell of less than 25%, less than 20%, less than 15%, or less than 10% after immersion in the chemical for 7 days at 70°C as determined from in accordance with EN ISO 10563. A multi-layer system prepared by using the methods provided by this disclosure can meet or exceed the requirements for aerospace senators set out in AMS 3277. A sealant is designed to minimize the penetration of gases and liquids to a surface during the use environment of the part being sealed. A multilayer system may comprise two or more layers where each of the layers can be designed to optimize one or more properties of the multilayer system. At least one of the layers may comprise a sealant layer. In a multi-layer system, an outer layer or outermost layer may comprise a sealer and may be designed, for example, to exhibit chemical resistance and an inner layer may be designed to exhibit, for example, adhesion to the substrate, low density and / or higher tensile strength and % elongation. As another example, the outer layer of a multi-layer system may exhibit a fast cure rate to facilitate handling and processing and the underlying layers may have slower cure rates which may facilitate, for example, improved adhesion and / or properties. improved mechanics. A multilayer system can also have the potential to reduce costs. Expensive materials can be used only in layers that are desired for their properties and other layers can use alternative materials. A multi-layer sealant system may comprise any suitable number of layers, such as 2, 3, 4, 5 or 6 layers, where each layer is formed from different materials and may exhibit different properties. A multi-layer sealant system can I 1 Π / I 7Π7 / 3 / ΥΙΛΙ comprise one sealant layer, more than one sealant layer or each layer may comprise one sealant layer. A multilayer system may comprise at least one sealer layer and each of the other layers may independently comprise a sealer layer or a non-sealer layer. A non-sealing layer is a layer that is not intended to function primarily as a sealant in the multi-layer sealant system, although a non-sealing layer may have some ability to restrict the penetration of gases and liquids. An example of a multilayer system is shown in Figures 1A and IB. The multi-layer system shown in Figure 1A includes a first inner layer 101 that underlies a second intermediate layer 102, which underlies a third outer layer 103. Figure IB shows a multi-layer system that overlies a fastener 105 mounted on a substrate 104 and includes a first inner layer 101, an overlying second intermediate layer 102 and an overlying third outer layer 103. Only the third outer layer 103 may comprise a sealer or all layers 101 / 102 / 103 may comprise a sealer. For example, inner layer 101 may comprise a composition configured to promote adhesion to a surface and intermediate layer 102 may comprise a composition having high tensile strength and % elongation. Another example of a multilayer system is shown in Figure IC in which a first layer 106 is adjacent to a second layer 107. Figure ID shows a multilayer system in which a first layer 106 is adjacent to a second layer 107 and a third layer 108 overlies the first and second layers 106 / 107. In Figure IC, the first layer 106 and / or the second layer 107 may be a sealant. In Figure ID, the outer layer 108 can be a sealant layer and the layers 106 and 107 can be non-sealant layers. In Figure ID, each of the layers 106 / 107 / 108 can be independently selected from a sealer layer and a non-sealer layer, wherein at least one of the layers 106 / 107 / 108 is a sealer layer. Other configurations of the various layers of a multilayer system are possible. At least one of the layers of a multilayer system may be different from another layer of the multilayer system. For example, the layers may differ in the type and / or amount of constituents, such as prepolymers, monomers, and / or additives in the layers. Differences in the type and / or amounts of the constituents can result in various layers of the multilayer system having different properties. Each of the layers can independently comprise, for example, reactive compounds, catalysts, polymerization initiators, adhesion promoters, fillers, reactive diluents, colorants, rheology control agents, and / or photochromic agents that can be the same or different or present in a different % by weight or % by volume than another layer of the multilayer system. I 7 n / I 7Π7 / 3 / ΥΙΛΙ The constituents of one layer may be different from those of another layer, for example, with respect to composition, cure chemistries, constituent molecular weights, constituent sizes, constituent weight % and / or constituent volume %. For example, each layer can be independently configured to provide a cured layer, eg, exhibiting one or more of chemical resistance, low temperature flexibility, hydrolytic stability, high temperature resistance, high tensile / elongation, substrate bonding, bond to primer coat, adhesion to adjacent coat, fast tack-free time, cure time to Shore 10A hardness, time to full cure, electrical conductivity, EMI / RFI shielding, static dissipation, resistance to corrosion, cured hardness, low density and / or acoustic insulation. Each of the layers of a multi-layer system can have the same or a different cure chemistry than another layer of the multi-layer system and / or an adjacent layer of the multi-layer system. To provide a robust interface between adjacent layers, it may be desirable for the adjacent layers to be chemically or physically bonded. The formation of chemical or physical bonds between layers can be facilitated by the use of coreactive compositions for adjacent layers that have the same curing chemistry and / or contain compounds capable of coreacting with compounds in adjacent layers. Adjacent layers of a coreactive composition can be chemically bonded and / or physically bonded to create a mechanically strong interlayer interface. The interface strength between layers can be determined by measuring the fracture energy in accordance with ASTM D7313. Chemically resistant multi-layer sealants made using the methods provided in the present disclosure can have a fracture energy that is substantially the same as the fracture energy of an individual layer. For example, the fracture energy of the multi-layer sealant and the fracture energy of an individual cured layer of the coreactive composition can be, for example, within less than 10%, less than 5%, less than 2%, or less than 1 %. Each coat in a multi-coat system can be selected to enhance a desired property or properties of individual cure coats. For example, an innermost layer may provide improved surface adhesion to a substrate, but not necessarily have low density. For example, an outermost layer can be formulated to provide improved chemical resistance and / or to be capable of dissipating static charge. An intermediate layer between the inner and outer layers can be low in density and formulated to exhibit improved mechanical properties. In this way, each layer of a multilayer system can be configured to optimize a different property or combination of properties without compromising other properties of a layer, where the other general properties of the system I 1 Π / I 7Π7 / 3 / ΥΙΛΙ multilayer can be delivered through other layers. A layer of a multilayer system may not be homogeneous within the horizontal plane of the layer and / or perpendicular to the horizontal plane of the layer. The inhomogeneity can be discrete or continuous. Figure 2A shows a cross section of a layer comprising, for example, an additive, such as a filler, in which the concentration of the filler, identified as being incipient, varies within the dimension perpendicular to the horizontal plane. of the layer. Figure 2B shows a cross section of a layer in which the filler concentration varies within the horizontal plane of the layer and, in certain regions, within the dimension perpendicular to the horizontal plane of the layer. The composition within a layer of a multilayer system can also vary within the layer. The composition can vary along the thickness of the layer, ie, the transverse dimension, and / or within a lateral dimension of a layer, ie, the longitudinal dimension. For example, a concentration of a constituent, such as a coreactive compound and / or an additive, can vary along the thickness of a layer, such that, for example, the concentration is higher towards one side of the layer than towards it. the opposite side of the layer, or the concentration may be higher in the middle of a layer than on either side. The concentration of one or more constituents can vary in a linear, non-linear, continuous, discontinuous, and / or discrete manner throughout the thickness of a layer. Similarly, a concentration of one or more constituents, such as a coreactive compound and / or an additive, can vary within a lateral dimension of a layer, such as in a dimension orthogonal to the thickness of the layer. For example, the concentration of a constituent, such as a compound and / or an additive, may be higher on one side of the layer than on the other side of the layer. The concentration or a constituent may vary within certain regions of the layer. The concentration of a constituent can vary in a linear, non-linear, continuous, discontinuous, and / or discrete manner along a lateral dimension of a layer. Each of the layers that form a multilayer system provided by the present disclosure can independently comprise an internal compositional structure. For example, the composition may be substantially uniform throughout the thickness of a layer or it may vary throughout the thickness of a layer. By uniform is meant that the concentration of each of the constituents forming a layer is within 10%, within 5%, within 1%, or within 0.1% of a nominal concentration throughout the layer, where the concentration nominal refers to an average concentration of the constituent within the layer. For example, the composition may be uniform within the thickness dimension of a layer or may vary within the lateral dimension, ie, orthogonal to the thickness dimension of a layer. I 1 n / I 7Π7 / 3 / ΥΙΛΙ A coreactive composition used to form a layer of a multilayer system can comprise at least two coreactive compounds and one or more additives. Within a layer, the concentration of a coreactive compound and / or the one or more additives can be substantially the same, such as within + / -5%, within + / -1%, or within + / -0.5 %. Alternatively, within a layer, the concentration of a coreactive compound and / or the one or more additives may vary. The concentration can vary along the thickness of a layer and / or in the longitudinal dimension of a layer. In turn, the concentration of a coreactive compound and / or the one or more additives may vary over a portion of the thickness and / or a portion of the longitudinal dimension of a layer. These layers can be referred to as structured layers to indicate that the layers are characterized by an internal compositional structure and that the composition is not uniform throughout the layer. The composition within a structured layer can vary in a discrete, continuous, discontinuous, linear, non-linear, or variable manner. A concentration of a constituent within a layer can vary discretely throughout the thickness of a layer. For example, an electrically conductive filler may be present in an outer portion of a layer to a certain depth and absent in the inner portion of the layer. A concentration of a constituent of a composition of a layer can vary, for example, in a linear or non-linear manner along the thickness or a portion of the thickness of a layer. A concentration of one or more constituents of a layer can be, for example, higher towards one surface, higher towards both surfaces or higher towards the center of the layer. A multilayer system can have any suitable physical structure as appropriate to seal a part that is intended to be sealed. For example, to seal a continuous two-dimensional surface, a multilayer system may be in the form of a multilayer sheet. To seal a small part, a multi-layer system can be in the form of a cap, cover, or any other suitable form. Each layer of a multilayer system may independently be of substantially uniform thickness or may be of variable thickness. The thickness of each layer can be substantially the same or can be different from another layer that forms a multilayer system. For example, a thickness of one layer may be substantially the same and may be within 10%, within 5%, or within 1% of another layer. For example, a thickness of one layer can be different from the thickness of another layer, it can be different by more than 10%, by more than I 1 n / 17Π7 / 3 / ΥΙΛΙ 20%, more than 50% or more than 100% of the thickness of another layer. For example, a multi-layer system used to seal a continuous two-dimensional surface may include multiple layers, where each layer is of substantially uniform thickness and where the thickness of an individual layer may be the same or different from the thickness of another layer. For example, a layer that is substantially uniform in thickness may have a thickness that does not vary by more than 10%, more than 5%, or more than 1% across the surface. A multi-layer system may have a total thickness of, for example, greater than 2mm, greater than 4mm, greater than 6mm, greater than 8mm, greater than 10mm, greater than 12mm or greater than 14mm. A multilayer system can have a total thickness of, for example, 2mm to 15mm, 3mm to 14mm, 3mm to 12mm, 4mm to 10mm or 6mm to 8mm. Each layer of a multilayer system can independently have a thickness, for example, from 0.1 mm to 25 mm, from 0.5 mm to 25 mm, from 1 mm to 20 mm, from 2 mm to 15 mm or from 3 mm to 10 mm. Each layer of a multilayer system can independently have a thickness, for example, greater than 0.1mm, greater than 0.5mm, greater than 1mm, greater than 5mm, greater than 10mm, greater than 15mm or greater than 20mm. Each layer of a multilayer system can independently have a thickness, for example, less than 25mm, less than 20mm, less than 15mm, less than 10mm, less than 5mm or less than 1mm. An outermost layer of a multilayer system may have a thickness that is greater than a thickness of each of the underlying layers, either individually or in combination. An outermost layer may have a thickness that is less than a thickness of each of the underlying layers, either individually or in combination. An inner layer may have a thickness that is greater than a thickness of each of the overlying layers, either individually or in combination. An inner layer may have a thickness that is less than a thickness of each of the overlying layers, either individually or in combination. To seal a three-dimensional part, an inner layer can have a variable cross-sectional thickness, such as to cover and conform to a complex shape of the part and to provide a smooth, continuous outer surface. The overlying layers may have a substantially uniform thickness. A multilayer system can be formed by extruding a coreactive sealer composition to form an extrudate and depositing the extrudate onto a substrate or a pre-deposited layer to form a sealant layer. The predeposited layer can be a sealer layer or a non-sealer layer. The pre-deposited layer may be the outermost layer of a multi-layer system. One or more layers can be deposited on the deposited sealer layer to form a multilayer system. I 1 n / L7n7 / q / YIAI A multilayer system can be applied to a substrate through the use of additive manufacturing technology, such as three-dimensional printing. Additive manufacturing methods facilitate the ability to apply a multi-layer system in a consistent and reproducible manner. In addition, in part because time constraints associated with hand-seal application methods are avoided, additive manufacturing allows the use of alternative cure chemistries, such as fast-cure chemistries. A coreactive sealant composition may comprise a first reactive compound and a second reactive compound where the first reactive compound is reactive with the second reactive compound. The first and second reactive compounds can react at a temperature less than 50°C, such as less than 40°C, less than 30°C, less than 25°C, less than 20°C or less than 15°C. The first and second reactive compounds can react in the absence of an activated polymerization catalyst and / or initiator. The first and second reactive compounds can react in the presence of a catalyst or combination of catalysts. The first and second reactive compounds can react in the presence of an activated polymerization initiator, such as an activated photoinitiator. The catalyst and polymerization initiator may be suitable for catalyzing or initiating a chemical reaction between the first reactive compound and the second reactive compound. A coreactive sealant composition may be a thermosetting composition such that the cured coreactive sealant composition may be a thermosetting. Each of the layers of a multilayer sealant system may comprise a thermoset. A coreactive sealant composition can be formed by combining and mixing a first component and a second component. The first component may comprise a first reactive compound and a second reactive compound; and the second component may comprise a catalyst and / or a polymerization initiator. The first component may comprise the first reactive compound and the second component may comprise the second reactive compound, and the first and / or second component may comprise a polymerization catalyst and / or initiator. In addition to a first component and a second component, a coreactive sealant composition can be formed by combining and mixing one or more additional components. A coreactive sealant composition can be formed, for example, by pumping a first component and a second component into a mixer and mixing the first and second components to form a coreactive sealant composition. A deposition system may include an in-line static and / or dynamic mixer as well as separate pressurized pumping compartments to contain the at least two components and feed the coreactive components to the static and / or dynamic mixer. A I 1 n / I 7Π7 / 3 / ΥΙΛΙ mixer such as an active mixer may comprise a variable speed center impeller having high shear blades within a conical nozzle. A range of tapered nozzles may be used having an exit orifice dimension, for example 0.2mm to 50mm, 0.5mm to 40mm, 1mm to 30mm or 5mm to 20mm. A range of static and / or dynamic mixing nozzles may be used having, for example, an outlet orifice dimension of 0.6mm to 2.5mm, and a length of 30mm to 150mm. For example, an exit orifice diameter may be 0.2mm to 4.0mm, 0.4mm to 3.0mm, 0.6mm to 2.5mm, 0.8mm to 2mm, or 1.0mm to 1.6mm. A static and / or dynamic mixer can have a length, for example, from 10 mm to 200 mm, from 20 mm to 175 mm, from 30 mm to 150 mm or from 50 mm to 100 mm. A mixing nozzle may include a static and / or dynamic mixing section and a dispensing section coupled to the static and / or dynamic mixing section. The static and / or dynamic mixing section can be configured to mix and match the components. The dispensing section can be, for example, a straight tube having any of the above orifice diameters. The length of the dispensing section can be configured to provide a region where the components can begin to react and build up viscosity before being deposited. The length of the dispensing section can be selected, for example, as a function of the rate of deposition, the rate of reaction of the coreactants, and the desired viscosity. A coreactive composition may have a static and / or dynamic mixing nozzle residence time, for example, 0.25 seconds to 5 seconds, 0.3 seconds to 4 seconds, 0.5 seconds to 3 seconds, or 1 second to 3 seconds. . Other residence times may be used as appropriate based on cure chemistries and cure rates. The flow rate can be, for example, 1 mL / min to 20 mL / min, 2 mL / min to 15 mL / min, 3 mL / min to 10 mL / min, or 4 mL / min to 8 mL / min, through a nozzle having a diameter, for example, from 0.8 mm to 1 mm. In general, a suitable residence time is less than the gel time of a coreactive composition. A suitable gel time may be less than 10 min, less than 8 min, less than 6 min, less than 5 min, less than 4 min, less than 3 min, less than 2 min, or less than 1 min. The gel time of the coreactive composition can be, for example, from 0.5 min to 10 min, from 1 min to 7 min, from 2 min to 6 min or from 3 min to 5 min. A coreactive composition for making a multi-layer sealant may have a gel time, for example, less than 12 hours, less than 8 hours, less than 4 hours, less than 1 hour, less than 30 minutes, less than 10 minutes, or less than 1 23C / 50%RH. A coreactive composition for making a multi-coat sealant may have a gel time, for example, from 10 seconds to 12 hours, from 1 minute to 8 hours, from 30 minutes to 4 hours, or from 1 hour to 3 hours at 23C / 50%. RH. A corrective composition for making a multi-layer sealant can I 1 η / I 7Π7 / 3 / ΥΙΛΙ have a gel time, for example, greater than 10 seconds, greater than 1 minute, greater than 30 minutes, greater than 1 hour, greater than 4 hours, or greater than 8 hours. "Gell time" refers to the length of time from the time that curing of the coreactive composition is initiated, for example, either by mixing coreactive components or by exposure to energy, such as UV radiation, to the time that the coreactive composition can no longer be stirred manually. A static and / or dynamic mixing nozzle can be heated or cooled to control, for example, the rate of reaction between the coreactive compounds and / or the viscosity of the coreactive composition. An orifice of a deposition nozzle can have any suitable shape and dimension. A system can comprise multiple deposition nozzles. The nozzles may have a fixed orifice dimension and shape, or the nozzle orifice may be controllably adjusted. The mixer and / or nozzle can be cooled to control an exotherm generated by the reaction of the coreactive compounds. The one or more additional layers of a multilayer system may be deposited by methods other than extrusion. For example, each layer that underlies and / or overlies a sealer layer can be deposited using any suitable method, such as by spraying, brushing, roller coating, and / or dispersing. Each of the one or more underlying and / or overlying layers may independently comprise a sealer layer or a non-sealer layer. In addition to a sealant layer of a multilayer system, other layers of the multilayer system can be formed by extrusion of a suitable coreactive composition. The one or more additional layers can be formed by combining and mixing a first component and a second component to form a co-reactive composition comprising a first reactive compound and a second reactive compound. Each of the one or more additional coreactive compositions can be fused with a coreactive sealant composition to form a coextrudate, which can be deposited together with the other layers of the multilayer system. Each of the additional coreactive compositions can be independently selected from an additional coreactive sealant composition or a coreactive non-sealant composition. The one or more additional layers may be formed by depositing the respective extrudates sequentially. Depositing sequentially means that an extrudate comprising a first coreactive composition is deposited, then a second extrudate comprising a second coreactive composition is deposited, and so on. In this way, a multilayer system is built layer by layer. Alternatively, one or more of the additional coreactive compositions can be coextruded with the coreactive sealer composition to form a coextrudate, which can be I ΗΓ1 n / L7n7 / q / YIAI deposit to simultaneously form all or a portion of the multilayer system. As with the coreactive sealant composition, each of the additional coextruded coreactive compositions can be formed by combining and mixing a first component and a second component to form the respective additional coreactive composition. Each of the additional coreactive compositions can be amalgamated with the coreactive sealant composition flow and coextruded through a coextrusion flask to form a coextrudate. The coextrudate can be deposited to form a multilayer system in which at least one of the layers is a sealer. Each of the additional coextruded coreactive compositions may independently comprise a coreactive sealer composition or a coreactive non-sealer composition and the respective layers comprise sealers or non-sealers. Each of the additional coextruded reactive compositions comprises a thermosetting material, which when cured forms a thermoset. Adjacent coreactive compositions that form the extrudate may comprise the same or different cure chemistries and / or may comprise reactive compounds capable of reacting with reactive compounds in an adjacent coreactive composition. This allows bonding between adjacent coreactive compositions providing a cured multilayer system in which adjacent layers are integrally bonded and have high cohesive strength. Each coreactive composition of a multilayer system, such as a coreactive sealer composition or a coreactive non-sealer composition, can independently comprise a first compound having a first functional group and a second compound comprising a second functional group, where the first functional group is capable of reacting with the second functional group. The first and second functional groups may be capable of reacting, for example, at a temperature of less than 50°C, less than 40°C, less than 30°C, less than 20°C or less than 15°C. The first and second functional groups may be capable of reacting, for example, at a temperature of 10°C to 50°C, 15°C to 40°C or 20°C to 30°C. The first and second functional groups may be capable of reacting, for example, at a temperature greater than 10°C, greater than 20°C, greater than 30°C, or greater than 40°C. A coreactive composition can be a one-part composition in which the curing reaction is initiated upon application of energy, such as by exposing the one-part coreactive composition to actinic radiation, such as UV radiation. A coreactive composition can be a two part composition in which the two coreactive components are combined and mixed to initiate the curing reaction. For example, a first component I br1 η / I 7Π7 / 3 / ΥΙΛΙ coreactive comprising a first compound comprising a first functional group may be combined and mixed with a second coreactive component comprising a second compound comprising a second functional group to form a coreactive composition, wherein the first and second functional groups are coreactive. The first and second coreactive components can be combined and mixed prior to being introduced into the coextruder or they can be combined and mixed within the extruder to form a coreactive composition that is fused with the flow of another coreactive composition. The properties of the multilayer system and the layers that make up the multilayer system, such as the viscosity and cure speed of the coreactive compositions, can be selected to facilitate the ability of an extrudate or coextrudate to retain an intended shape upon deposition on the surface. A coreactive composition may have an initial viscosity, as deposited, for example, of 1E2 poise to 1E7 poise, 5E2 poise to 5E6 poise, 1E3 poise to 1E5 poise, or 5E3 poise to 5E4 poise, where the viscosity is determined by using a Brookfield rheometer set with a #7 paddle at 2 rpm and 25°C. A coreactive composition can have an initial viscosity, for example, greater than 1E2 poise, greater than 5E2 poise, greater than 1E3 poise, greater than 5E3 poise, greater than 1E4 poise, greater than 1E5 poise, or greater than 1E6 poise. A coreactive composition may have an initial viscosity, for example, less than 1E7 poise, less than 1E6 poise, less than 1E5 poise, less than 1E4 poise, or less than 1E3 poise. A coreactive composition can be tack free, eg, less than 24 hours, less than 10 hours, less than 1 hour, less than 30 minutes, less than 10 minutes, or less than 5 minutes at 23°C / 50%RH. A coreactive composition for making a multi-coat sealant may have a tack-free time, for example, greater than 10 seconds, greater than 1 minute, greater than 1 hour, greater than 6 hours, or greater than 12 hours at 23°C / 50%. RH. A coreactive composition can be tack free, for example, 30 seconds to 24 hours, 1 minute to 12 hours, 1 hour to 10 hours, or 2 hours to 8 hours at 23°C / 50%RH. Tack-free time refers to the length of time from the time cure of the coreactive composition is initiated, for example, either by mixing coreactive components or by exposure to energy such as UV radiation, to the time a layer prepared from the coreactive composition is no longer tack free, where tackiness is determined by applying a polyethylene sheet to the surface of the layer with hand pressure and observing if the sealant adheres to the surface of the sheet of polyethylene, where A coreactive composition may have a time to Shore 10A hardness, for example, less than 2 minutes, less than 5 minutes, less than 30 minutes, less than 1 hour, less than 5 hours, less than 10 hours, or less than 20 hours. at 23°C / 50%RH. A composition I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ can have a time up to Shore 10A hardness, for example, greater than 30 seconds, greater than 1 minute, greater than 1 hour, greater than 5 hours or greater than 10 hours a 23°C / 50%RH. A coreactive composition may have a time to Shore 10A hardness, for example, 30 seconds to 20 hours, one minute to 12 hours, or 1 hour to 10 hours, at 23°C / 50%RH. A coreactive composition may have a cure time such as time to Shore 30A hardness from 1 day to 7 days at 23°C / 50%RH. A corrective composition may have a long working time and, after the working time is complete, may have a rapid cure time. Working time refers to the time from when the coreactive compounds are first combined and mixed to form the coreactive composition until the coreactive composition can no longer be manually agitated; or the time from when a catalyst is added and / or a polymerization initiator is activated to cause the coreactive compounds to react to the time the coreactive composition can no longer be manually stirred. Each coreactive composition used to form a multilayer system can independently comprise one or more prepolymers, one or more monomers, and one or more additives. A coreactive composition can be a thermosetting composition and when cured can form a thermoset. A coreactive composition can be substantially free of solvent. For example, a coreactive composition may comprise less than 5% by weight of solvent, less than 2% by weight, less than 1% by weight, or less than 0.1% by weight of solvent, where the % by weight is a function of the total weight of the coreactive composition. A coreactive composition may comprise coreactive compounds that coreact and cure at room temperature, where room temperature refers to a temperature of 20°C to 25°C, 20°C to 22°C, or around 20°C. A prepolymer can comprise any backbone. A prepolymer backbone can be selected, for example, based on the end-use requirements of a multilayer system and the desired attributes of a particular layer. A coreactive composition can comprise a prepolymer or a combination of prepolymers. Prepolymers can influence, for example, the tensile strength, % elongation, hydrolytic stability and / or chemical resistance, as well as other properties of the cured sealant. A prepolymer may have a number average molecular weight, for example, less than 20,000 Da, less than 15,000 Da, less than 10,000 Da, less than 8,000 Da, less than I / n / 17Π7 / 3 / ΥΙΛΙ 6,000 Da, less than 4,000 Da or less than 2,000 Da. A prepolymer can have a number average molecular weight, for example, greater than 2,000 Da, greater than 4,000 Da, greater than 6,000 Da, greater than 8,000 Da, greater than 10,000 Da or greater than 15,000 Da. A prepolymer may have a number average molecular weight, for example, from 1,000 Da to 20,000 Da, from 2,000 Da to 10,000 Da, from 3,000 Da to 9,000 Da, from 4,000 Da to 8,000 Da or from 5,000 Da to 7,000 Da. A prepolymer may be liquid at 25°C and may have a glass transition temperature Tg, for example, less than -20°C, less than -30°C or less than -40°C. A prepolymer may exhibit a viscosity, for example, in the range of 20 poise to 500 poise (2 Pa-s to 50 Pa-s), 20 poise to 200 poise (2 Pa-s to 20 Pa-s), or 40 poise to 120 poise (4 Pa-s to 12 Pa-s), measured by a Brookfield CAP 2000 viscometer, with a No. 6 spindle, at a speed of 300 rpm, and a temperature of 25°C. A prepolymer may have a reactive functionality, for example, less than 12, less than 10, less than 8, less than 6, or less than 4. The first reactive compound and the second reactive compound may each comprise a prepolymer having the functionality respective reactive, for example, 2 to 12, 2 to 8, 2 to 6, 2 to 4, or 2 to 3. Each of the first reactive compound and the second reactive compound may independently have a functionality, for example , of 2, 3, 4, 5 or 6. A coreactive composition may comprise a prepolymer or combination of prepolymers having any suitable polymeric backbone. For example, a polymeric backbone can be selected that imparts solvent resistance to the cured coreactive composition or imparts desired physical properties, such as tensile strength, % elongation, Young's modulus, impact strength, or other property relevant to the composition. application. A prepolymer backbone may terminate in one or more functional groups suitable for a particular cure chemistry. A prepolymer can comprise segments that have different chemical structures and properties within the main chain of the prepolymer. Segments can be distributed randomly, in a regular distribution, or in blocks. The segments can be used to impart certain properties to the backbone of the prepolymer. For example, the segments can comprise flexible linkages such as thioether linkages in the polymer backbone. Segments having pendant groups can be incorporated into the backbone of the prepolymer. For example, a prepolymer backbone can comprise a polythioether, a polysulfide, a polyformal, a polyisocyanate, a polyurea, polycarbonate, polyphenylene sulfide, polyethylene oxide, polystyrene, acrylonitrile-butadiene-styrene, polycarbonate, styrene acrylonitrile, poly (methylmethacrylate), polyvinylchloride, polybutadiene, polybutylene terephthalate, poly(p7 I br1 n / I 7Π7 / 3 / ΥΙΛΙ phenyleneoxide), polysulfone, polyether sulfone, polyethyleneimine, polyphenylsulfone, acrylonitrile styrene acrylate, polyethylene, syndiotactic polypropylene or isotactic, polylactic acid, polyamide, ethyl vinyl acetate homopolymer or copolymer, polyurethane, ethylene copolymers, propylene copolymers, impact propylene copolymers, polyether ether ketone, polyoxymethylene, syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS) ), liquid crystalline polymer (LCP), butene homopolymer and copolymer, hexene homopolymers and copolymers; and combinations of any of the foregoing. Examples of other prepolymer backbones include polyolefins (such as polyethylene, linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene, polypropylene, and olefin copolymers), styrene / butadiene rubbers ( SBR), styrene / ethylene / butadiene / styrene copolymers (SEBS), butyl rubbers, ethylene / propylene copolymers (EPR), ethylene / propylene / diene monomer copolymers (EPDM), polystyrene (including high impact polystyrene) , poly(vinyl acetates), ethylene / vinyl acetate copolymers (EVA), poly(vinyl alcohols), ethylene / vinyl alcohol copolymers (EVOH), poly(vinyl butyral), poly(methyl methacrylate) and others acrylate polymers and copolymers (including those such as methyl methacrylate polymers, methacrylate copolymers, polymers derived from one or more acrylates, methacrylates, ethyl acrylates, ethyl methacrylates, butyl acrylates, butyl methacrylates, and the like), copolymers olefin styrene, acrylonitrile / butadiene / styrene (ABS), styrene / acrylonitrile (SAN) polymers, styrene / maleic anhydride copolymers, isobutylene / maleic anhydride copolymers, ethylene / acrylic acid copolymers, poly(acrylonitrile), polycarbonates (PC), polyamides, polyesters, liquid crystalline polymers (LCP), poly(lactic acid), poly(phenylene oxide) (PPO), PPO-polyamide alloys, polysulfone (PSD), polyether ketone (PEK), polyether ether Ketone (PEEK), polyimides, polyoxymethylene (POM) homopolymers and copolymers, polyetherimides, fluorinated ethylene propylene polymers (FEP), poly(vinyl fluoride), poly(vinylidene fluoride), poly(vinylidene doride) and poly( vinyl chloride), polyurethanes (thermoplastic and thermosetting), aramids (such as Kevlar® and Nomex®), polytetrafluoroethylene (PTFE), polysiloxanes (including polydimethylenesiloxane, dimethylsiloxane / vinylmethylsiloxane copolymers, terminated poly(dimethylsiloxane) in vinyldimethylsiloxane), elastomers, epoxy polymers, polyureas, alkyds, cellulosic polymers (such as ethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, cellulose acetate, cellulose acetate propionates and cellulose acetate butyrates), polyethers and glycols such as poly (ethylene oxides) (also called poly(ethylene glycols)), poly(propylene oxides) (also called poly(propylene glycols)) and ethylene oxide / propylene oxide copolymers, acrylic latex polymers, oligomers and polyester acrylate polymers, polyester diol diacrylate polymers, and UV-curable resins. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ A coreactive composition may comprise a prepolymer comprising an elastomeric backbone. Elastomer, elastomeric, and similar terms refer to materials with rubber-like properties and generally having a low Young's modulus and high tensile strain. For example, elastomers can have a Young's modulus / tensile strength of from about 4 MPa to about 30 MPa. Elastomers can have a tensile set (elongation at break) of about 100% to about 2,000%. Young's Modulus / tensile strength and tensile strain can be determined in accordance with ASTM D412.4893. Elastomers can exhibit a tear strength of, for example, from 50 kN / m to 200 kN / m. Tear strength can be determined in accordance with ASTM D624. The Young's modulus of an elastomer can range from 0.5 MPa to 6 MPa as determined in accordance with ASTM D412.4893. Examples of suitable prepolymers having an elastomeric backbone include polyethers, polybutadienes, fluoroelastomers, perfluoroelastomers, ethylene / acrylic copolymers, ethylene propylene diene terpolymers, nitriles, polythiolamines, polysiloxanes, chlorosulfonated polyethylene rubbers, isoprenes, neoprenes, polysulfides, polythioethers , silicones, styrene butadienes and combinations of any of the above. An elastomeric prepolymer can comprise a polysiloxane, such as, for example, a polymethylhydrosiloxane, polydimethylsiloxane, polyhydrodiethylsiloxane, polydiethylsiloxane, or a combination of any of the foregoing. The elastomeric prepolymer may comprise terminal functional groups that have low reactivity with amine and isocyanate groups such as silanol groups. Examples of prepolymers that exhibit high solvent resistance include fluoropolymers, ethylene propylene diene terpolymer (EPDM) and other chemically resistant prepolymers disclosed herein, cured polymer matrices having high crosslink density, chemically resistant organic filler such as polyamides, polyphenylene sulfides and polyethylenes, or a combination of any of the foregoing. Examples of prepolymers having a chemically resistant backbone include polytetrafluoroethylene, polyvinylidene difluoride, polyethylenetetrafluoroethylene, fluorinated ethylene propylene, perfluoroalkoxy, ethylene chlorotrifluoroethylene, polychlorotrifluoroethylene, fluorinated ethylene propylene polymers polyamide, polyethylene, polypropylene, ethylene-propylene, fluorinated ethylenepropylene, polysulfone , polyaryl ether sulfone, polyether sulfone, polyimide, polyethylene terephthalate, polyether ketone, polyether ether ketone, polyetherimide, polyphenylene sulfide, polyaryl sulfone, polybenzimidazole, polyamideimide, liquid crystal polymers, and combinations of any of the foregoing. I br1 n / L7n7 / q / YIAI Examples of prepolymers that exhibit low temperature flexibility include silicones, polytetrafluoroethylenes, polythioethers, polysulfides, polyformals, polybutadienes, certain elastomers, and combinations of any of the foregoing. Examples of prepolymers that exhibit hydrolytic stability include silicones, polytetrafluoroethylenes, polythioethers, polysulfides, polyformals, polybutadienes, certain elastomers and combinations of any of the foregoing, and compositions having high crosslink density. Examples of prepolymers that exhibit high temperature resistance may comprise, for example, prepolymers such as silicones, polytetrafluoroethylenes, polythioethers, polysulfides, polyformals, polybutadienes, certain elastomers, and combinations of any of the foregoing, and compositions having high crosslink density. . Examples of prepolymers that exhibit high tensile strength include silicones and polybutadiene, compositions that have high crosslink density, inorganic filler, and combinations of any of the foregoing. A coreactive sealant composition may comprise a sulfur-containing prepolymer or a combination of sulfur-containing prepolymers. Sulfur-containing monomers and prepolymers can impart solvent resistance to a cured sealant. For applications where chemical resistance is required, prepolymers having a sulfur-containing backbone can be used. Chemical resistance can be with respect to cleaning solvents, fuels, hydraulic fluids, lubricants, oils, and / or salt spray. Chemical resistance refers to the ability of a part to maintain acceptable physical and mechanical properties after exposure to atmospheric conditions such as humidity and temperature and after exposure to chemicals such as cleaning solvents, fuels, hydraulic fluids, lubricants, etc. and / or oils. In general, a chemically resistant part that will exhibit a % swell of less than 25%, less than 20%, less than 15%, or less than 10% after immersion in a chemical for 7 days at 70°C, where the % of Swelling is determined according to EN ISO 10563. A sulfur-containing prepolymer refers to a prepolymer having one or more thioether groups -Sn-, where n can be, for example, from 1 to 6, in the main chain of the prepolymer. Prepolymers containing only thiol or other sulfur-containing groups either as end groups or as pendant groups of the prepolymer are not encompassed by sulfur-containing prepolymers. The prepolymer backbone refers to the part of the prepolymer that has repeating segments. Therefore, a prepolymer having the structure HS-R-R(-CH2-SH)-[-R-(CH2)2-S(O)2-(CH2)-S(O)2]n-CH=CH2 , where each R is a moiety that does not contain a sulfur atom in the main chain of the prepolymer, is not encompassed by sulfur-containing prepolymer. A prepolymer having the structure HS-R-R(-CH2-SH)-[-R7 I br1 n / I 7Π7 / 3 / ΥΙΛΙ (CH2)2-S(O)2-(CH2)-S(O)2] -CH=CH2, where at least one R is a moiety containing a sulfur atom, such as a thioether group, is encompassed by sulfur-containing prepolymer. Sulfur-containing prepolymers having a high sulfur content can impart chemical resistance to a cured coreactive composition. For example, a sulfur-containing prepolymer backbone may have a sulfur content greater than 10% by weight, greater than 12% by weight, greater than 15% by weight, greater than 18% by weight, greater than 20% by weight, weight or greater than 25% by weight, where the % by weight is a function of the total weight of the main chain of prepolymer. A chemically resistant prepolymer backbone can have a sulfur content, for example, from 10% by weight to 25% by weight, from 12% by weight to 23% by weight, from 13% by weight to 20% by weight or from 14% by weight to 18% by weight, where the % by weight is a function of the total weight of the main prepolymer chain. Sulfur content can be determined in accordance with ASTM D297. Examples of prepolymers having a sulfur-containing backbone include polythioether prepolymers, polysulfide prepolymers, sulfur-containing polyformal prepolymers, monosulfide prepolymers, and a combination of any of the foregoing. The sealant coreactive composition can comprise, for example, from 40% by weight to 80% by weight, from 40% by weight to 75% by weight, from 45% by weight to 70% by weight or from 50% by weight to 70 % by weight of a sulfur-containing prepolymer or a combination of sulfur-containing prepolymers, where the % by weight is based on the total weight of the coreactive composition. A sealant coreactive composition can comprise, for example, more than 40% by weight, more than 50% by weight, more than 60% by weight, more than 70% by weight, more than 80% by weight or more than 90% in weight of a sulfur-containing prepolymer or a combination of sulfur-containing prepolymers, where the % by weight is based on the total weight of the coreactive sealant composition. A sealant coreactive composition may comprise, for example, less than 90% by weight, less than 80% by weight, less than 70% by weight, less than 60% by weight, less than 50% by weight or less than 40% by weight. weight of a sulfur-containing prepolymer or a combination of sulfur-containing prepolymers, where the % by weight is based on the total weight of the coreactive sealant composition. A coreactive sealant composition for forming a cured sealant layer exhibiting fuel resistance may comprise, for example, prepolymers having a sulfur content greater than 10% by weight, where the % by weight is a function of the total weight of the prepolymer, rubber such as polybutadiene and ethylene propylene diene terpolymer (EPDM), a high crosslink density chemically resistant organic filler such as polyamides, polyphenylene sulfides and polyethylenes, or a combination of any of the foregoing. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ A sulfur-containing prepolymer can comprise a polythioether prepolymer or a combination of polythioether prepolymers. A polythioether prepolymer may comprise a polythioether prepolymer comprising at least a portion having the structure of Formula (1), a thiol-terminated polythioether prepolymer of Formula (la), a terminally modified polythioether of Formula (Ib) or a combination of any of the above: -S-RHS-A-S-RHn-S-(1) HS-RHS-A-S-RHn-SH(la) R^S-R^ES-A-S-R^Jn-S-R3(Ib) where n can be an integer from 1 to 60; each R1 can be independently selected from C2-10 alkandiyl, Ce-scycloalkandiyl, Ce-14 alkanecycloalkandiyl, C5-8 heterocycloalkandiyl, and -[(CHR)p-X-]q(CHR)i~, where p can be an integer from 2 to 6; q can be an integer from 1 to 5; r can be an integer from 2 to 10; each R can be independently selected from hydrogen and methyl; and each X can be independently selected from O, S, and S-S; and each A may independently be a moiety derived from a polyvinyl ether of Formula (2) or a polyalkenyl polyfunctional agent of Formula (3): CH2=CH-O-(R2-O)m-CH=CH2(2) B(-R4-CH=CH2)z (3) where m can be an integer from 0 to 50; each R2 can be independently selected from C1-10alkandiyl, Cs-scycloalkandiyl, Ce-14alkancycloalkandiyl, and -[(CHR)P-X-]q(CHR),-, where p, q, r, R, and X are as defined for R1; B represents a core of an agent with polyalkenyl polyfunctionality zva lens B(-R4-CH=CH2)z where z can be an integer from 3 to 6; each R4 can be independently selected from C1-10 alkandiyl, C1-10 heteroalkandiyl, substituted C1-10 alkandiyl and substituted C1-10 heteroalkandiyl; and each R3 can independently be a moiety comprising a terminal reactive group; In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 may be C2-10alkandiyl. I br1 n / I 7Π7 / 3 / ΥΙΛΙ In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 can be -[(CHR)p-X-]q(CHR)i~. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), X may be selected from O and S and thus -[(CHR)p-X-]q(CHR)r- may be -[( CHR)p-O-]q(CHR)r- or -[(CHR)p-S-]q(CHR)r~. P and r can be equal, such as where both p and r can be two. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 may be selected from C2-6alkandiyl and -[(CHR)p-X-]q(CHR)r-. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 can be -[(CHR)p-X-]q(CHR)r- and X can be O or X can be S. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), where R1 can be -[(CHR)p-X-]q(CHR),~, p can be 2, r can be 2, q can be 1 and X can be S; or p can be 2, q can be 2, r can be 2, and X can be 0; or p can be 2, r can be 2, q can be 1, and X can be 0. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 can be -[(CHR)p-X-]q(CHR),~, each R can be hydrogen or at least one R can be methyl. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 can be -[(CH2)P-X-]q(CH2)r- where each X can be independently selected from O and S. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 can be -[(CH2)P-X-]q(CH2)r-, where each X can be 0 or each X can be S. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), R1 may be -[(CH2)P-X-]q(CH2),-, where p may be 2, X may be 0, q can be 2, r can be 2, R2 can be ethanediyl, m can be 2, and n can be 9. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), each R1 can be derived from 1,8-dimercapto-3,6-dioxaoctane (DMDO; 2,2-(ethane-1,2- diylbis(sulfan11))bis(ethane1-thiol)) or each R1 can be derived from di merca ptodiethylsulfide (DMDS; 2,2'-thiobis(ethane1-thiol))) and combinations thereof. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), each p may be independently selected from 2, 3, 4, 5, and 6. Each p may be the same and may be 2, 3, 4 , 5 or 6. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), each q can independently be 1, 2, 3, 4, or 5. Each q can be the same and can be 1, 2, 3, 4 or 5. In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), each r can independently be 2, 3, 4, 5, 6, 7, 8, 9, or 10. Each r can be equal to and it can be 2, 3, 4, 5, 6, 7, 8, 9 or 10. I br1 n / I 7Π7 / 3 / ΥΙΛΙ In portions of Formula (1) and prepolymers of Formulas (la) and (Ib), each r can independently be an integer from 2 to 4, 2 to 6, or 2 to 8. In divinyl ethers of Formula (2), m can be an integer from 0 to 50, such as 0 to 40, 0 to 20, 0 to 10, 1 to 50, 1 to 40, 1 to 20, 1 to 10, 2 to 50, 2 to 40, 2 to 20, or 2 to 10. In divinyl ethers of Formula (2), each R2 can be independently selected from a C2-10 n-alkandiyl group, a branched C3-6 alkandiyl group, and a -[(CH2)p-X-]q(CH2)1- group. In divinyl ethers of Formula (2), each R 2 can independently be a C 2-10 n-alkandiyl group, such as methandiyl, ethanediyl, n-propandiyl or n-butandiyl. In divinyl ethers of Formula (2), each R2 may independently comprise a group -[(CH2)p-X-]q(CH2)i~, where each X may be O or S. In divinyl ethers of Formula (2), each R2 may independently comprise a group -[(CH2)p-X-]q(CH2)1-. In divinyl ethers of Formula (2), each m can independently be an integer from 1 to 3. Each m can be the same and can be 1, 2, or 3. In divinyl ethers of Formula (2), each R2 can be independently selected from a C2-10 n-alkandiyl group, a branched C3-6 alkandiyl group, and a -[(CH2)p-X-]q(CH2V. In divinyl ethers of Formula (2), each R2 can independently be a C2-10 n-alkandiyl group. In divinyl ethers of Formula (2), each R2 can independently be a group -[(CH2)p-X-]q(CH2),-, where each X can be O or S. In divinyl ethers of Formula (2), each R2 can independently be a group -[(CH2)P-X-]q(CH2)1-, where each X can be O or S, and each p can independently be 2, 3 , 4, 5 and 6. In divinyl ethers of Formula (2), each p may be the same and may be 2, 3, 4, 5, or 6. In divinyl ethers of Formula (2), each R2 can independently be a group -[(CH2)P-X-]q(CH2)^, where each X can be O or S, and each q can independently be 1, 2, 3, 4 or 5. In divinyl ethers of Formula (2), each q can be the same and can be 1, 2, 3, 4, or 5. In divinyl ethers of Formula (2), each R2 can independently be a -[(CH2)p-X-]q(CH2)i- group, where each X can be O or S, and each r can independently be I br1 η / I 7Π7 / 3 / ΥΙΛΙ 2, 3, 4, 5, 6, 7, 8, 9 or 10. In divinyl ethers of Formula (2), each r can be the same and can be 2, 3, 4, 5, 6, 7, 8, 9, or 10. In divinyl ethers of Formula (2), each r can independently be an integer from 2 to 4, 2 to 6, or 2 to 8. Examples of suitable divinyl ethers include ethylene glycol divinyl ether (EG-DVE), butanediol divinyl ether (BD-DVE), hexanediol divinyl ether (HD-DVE), diethylene glycol divinyl ether (DEG-DVE ), triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, polytetrahydrofuryl divinyl ether, cyclohexanedimethanol divinyl ether, and combinations of any of the foregoing. A divinyl ether may comprise a sulfur-containing divinyl ether. Examples of suitable sulfur-containing divinyl ethers are disclosed, for example, in PCT Publication No. WO 2018 / 085650. In portions of Formula (1), each A can be independently derived from an agent with polyalkenyl polyfunctionality. An agent with polyalkenyl polyfunctionality can have the structure of Formula (3), where z can be 3, 4, 5, or 6. In polyalkenyl polyfunctionalizing agents of Formula (3), each R4 may be independently selected from Ci-io alkandiyl, Ci-io heteroalkandiyl, Ci-io substituted alkandiyl or Ci-io substituted heteroalkandiyl. The one or more substituent groups may be selected from, for example, -OH, =0, Ci-4 alkyl and Ci-4 alkoxy. The one or more heteroatoms may be selected from, for example, O, S, and a combination thereof. Examples of suitable polyalkenyl polyfunctional agents include triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), 1,3,5-triallyl-1,3,5-triazinan-2,4,6-trione, 1, 3,5-triallyl-1,3,5-triazinan-2,4,6-trione, 1,3-bis(2-methylallyl)-6-methylene-5-(2-oxopropyl)-1,3,5 -triazinon2,4-dione, tris(allyloxy)methane, pentaerythritol triallyl ether, l-(allyloxy)-2,2bis((allyloxy¡)methyl)butane, 2-prop-2-ethoxy-1,3 ,5-tr¡s(prop-2-en¡l)benzene, l,3,5-tris(prop-2-enyl)-l,3,5triaz¡nan-2,4-dione and l,3,5 -tr¡s(2-methylal¡l)-l,3,5-triazinan-2,4,6-tr¡one, 1,2,4-trivinylcyclohexane, trimethylolpropane trivinyl ether and combinations of any of the above. In portions of Formula (1) and prepolymers of Formulas (la)-(lb), the molar ratio of portions derived from a divinyl ether to portions derived from a polyalkenyl polyfunctional agent may be, for example, from 0.9% mole to 0.999% mole, from 0.95% mole to 0.99% mole or from 0.96% mole to 0.99% mole. In portions of Formula (1) and prepolymers of Formulas (la)-(lb), each R1 can be -(CH2)2-O-(CH2)2-O-(CH2)2-; each R2 can be -(CH2)2-; and m can be an integer from 1 to 4. I bP / Π / I 7Π7 / 3 / ΥΙΛΙ In portions of Formula (1) and prepolymers of Formulas (la)-(lb), each R2 can be derived from a divinyl ether such as a diethylene glycol divinyl ether, an agent with polyalkenyl polyfunctionality such as triallyl cyanurate or a combination of these. In portions of Formula (1) and prepolymers of Formulas (la)-(lb), each A can be independently selected from a portion of Formula (2a) and a portion of Formula (3a): -(CH2)2-O-(R2-O)m-(CH2)2- (2a) B{-R4-(CH2)2-}2{-R4-(CH2)2-S-[-R1-S-A-S-R1-]n-SH}z-2 (3a) where m, R1, R2, R4 , A, B, m, n and z are defined as in Formula (1), Formula (2) and Formula (3). In portions of Formula (1) and prepolymers of Formula (la)-(lb), each R1 can be -(CH2)2-O-(CH2)2-O-(CH2)2-; each R2 can be -(CH2)2-; m can be an integer from 1 to 4; and the agent with polyfunctionality B(-R4-CH=CH2)z comprises triallyl cyanurate where z is 3 and each R4 can be -O-CH2-CH=CH2. Methods for synthesizing sulfur-containing polythioethers are disclosed, for example, in US Patent No. 6,172,179. The backbone of a thiol-terminated polythioether prepolymer can be modified to increase one or more properties such as adhesion, tensile strength, elongation, UV resistance, hardness, and / or flexibility of senators prepared through the use of prepolymers. of polythioether. For example, adhesion promoting groups, antioxidants, metal ligands, and / or urethane linkages can be incorporated into the backbone of a polythioether prepolymer to improve one or more performance attributes. Examples of backbone-modified polythioether prepolymers are disclosed, for example, in US Patent No. 8,138,273 (containing urethane), US Patent No. 9,540,540 (containing sulfone), US Patent No. 8,952,124 (containing bis(sulfonyl)alkanol), US Patent No. 9,382,642 (containing metal ligand), US Application Publication No. 2017 / 0114208 (containing antioxidants), PCT International Publication No. WO 2018 / 085650 (sulfur-containing divinyl ether) and PCT International Publication No. WO 2018 / 031532 (containing urethane), each of which is incorporated by reference in its entirety. Polythioether prepolymers include the prepolymers described in US Application Publication Nos. 2017 / 0369737 and 2016 / 0090507. Examples of suitable thiol-terminated polythioether prepolymers are disclosed, for example, in US Patent No. 6,172,179. A thiol-terminated polythioether prepolymer can comprise Permapol® P3.1E, Permapol® P3.1E-2.8, Permapol® L56086, or a combination of any of the foregoing, each of which is available from PPG. I br1 n / I 7Π7 / 3 / ΥΙΛΙ Aerospace. These Permapol® products are encompassed by the thiol-terminated polythioether prepolymers of Formulas (1), (la) and (Ib). Thiol-terminated polythioethers include the prepolymers described in US Patent No. 7,390,859 and the urethane-containing polythiols described in US Application Publication Nos. 2017 / 0369757 and 2016 / 0090507. A sulfur-containing prepolymer can comprise a polysulfide prepolymer or a combination of polysulfide prepolymers. A polysulfide prepolymer refers to a prepolymer that contains one or more polysulfide bonds, ie, -Sx- bonds, where x is from 2 to 4, in the backbone of the prepolymer. A polysulfide prepolymer can have two or more sulfur-sulfur bonds. Suitable thiol-terminated polysulfide prepolymers are commercially available, for example, from AkzoNobel and Toray Industries, Inc. under the tradenames Thioplast® and Thiokol-LP®, respectively. Examples of suitable polysulfide prepolymers are disclosed, for example, in US Patent Nos. 4,623,711; 6,172,179; 6,509,418; 7,009,032; and 7,879,955. Examples of suitable thiol-terminated polysulfide prepolymers include Thioplast® G polysulfides, such as Thioplast® Gl, Thioplast® G4, Thioplast® G10, Thioplast® G12, Thioplast® G21, Thioplast® G22, Thioplast® G44, Thioplast® G122 and Thioplast® G131, which are commercially available from AkzoNobel. Suitable thiol-terminated polysulfide prepolymers, such as Thioplast® G resins, are liquid thiol-terminated polysulfide prepolymers that are mixtures of difunctional and trifunctional molecules wherein the difunctional thiol-terminated polysulfide prepolymers have the structure of Formula (4 ) and trifunctional thiol-terminated polysulfide polymers may have the structure of Formula (5): HS-(-R5-S-S-)n-R5-SH (4) HS-(-R5-S-S-)a<H2-CH{-CH2-(-S-S-R5-)b-SH}{-(-S-S-R5-)c-SH} (5) where each R5 is -( CH2)2-O-CH2-O-(CH2)2- and n = a + b + c, where the value of n can be from 7 to 38 depending on the amount of the trifunctional crosslinking agent (1,2,3-trichloropropane ;TCP) used during the synthesis of the polysulfide prepolymer. Thioplast® G polysulfides can have a number average molecular weight of less than 1,000 Da to 6,500 Da, a -SH content of 1% by weight to more than 5.5% by weight and a crosslink density of 0% by weight to 2.0% by weight. A polysulfide prepolymer may further comprise a terminally modified polysulfide prepolymer having the structure of Formula (4a), a terminally modified polysulfide prepolymer having the structure of Formula (5a), or a combination I br1 n / I 7Π7 / 3 / ΥΙΛΙ of these: R3-S-(-R5-S-S-)n-R5-S-R3(4a) R3-S-(-R5-S-S-)a-CH2-CH{-CH2-(-S-S-R5-)b-S-}{-(-S-S-R5-)c-S-R3} (5a) where n, a , b, c and R5 are defined as for Formula (4) and Formula (5), and R3 is a moiety comprising a terminal reactive group. Examples of suitable thiol-terminated polysulfide prepolymers also include the Thiokol® LP polysulfides available from Toray Industries, Inc., such as Thiokol® LP2, Thiokol® LP3, Thioko® LP12, Thiokol® LP23, Thiokol® LP33, and Thiokol® LP33. ®LP55. Thiokol® LP polysulfides have a number average molecular weight of 1,000 Da to 7,500 Da, a -SH content of 0.8% to 7.7%, and a crosslink density of 0% to 2%. Thioko® LP polysulfide prepolymers have the structure of Formula (6) and end-modified polysulfide prepolymers may have the structure of Formula (6a): HS-[(CH2)2-O-CH2-O-(CH2)2-S-S-]n-(CH2)2-O-CH2-O-(CH2)2-SH (6) R3-S-[(CH2)2-O-CH2-O-(CH2)2-S-S-]n-(CH2)2-O-CH2-O-(CH2)2-S-R3(6a) where n it may be such that the number average molecular weight is from 1,000 Da to 7,500 Da, such as, for example, an integer from 8 to 80, and each R3 is a moiety comprising a terminal reactive functional group. A thiol-terminated sulfur-containing prepolymer may comprise a Thiokol-LP® polysulfide, a Thioplast® G polysulfide, or a combination thereof. A polysulfide prepolymer may comprise a polysulfide prepolymer comprising a portion of Formula (7), a thiol-terminated polysulfide prepolymer of Formula (7a), a terminal-modified polysulfide prepolymer of Formula (7b), or a combination of any of the above: -R6-(Sy-R6)t-(7) HS-R6-(Sy-R6)t-SH(7a) R3-S-R6-(Sy-R6)t-S-R3(7b) where t can be an integer from 1 to 60; each R6 can be independently selected from branched alkandiyl, branched areniyl, and a moiety having the structure -(CH2)P-O-(CH2)q-O-(CH2)i~; q can be an integer from 1 to 8; p can be an integer from 1 to 10; r can be an integer from 1 to 10; and can have an average value within a range of 1.0 to 1.5; and each R3 is a moiety comprising a terminal reactive functional group. I br1 n / I 7Π7 / 3 / ΥΙΛΙ In portions of Formula (7) and prepolymers of Formulas (7a)-(7b), 0% to 20% of the R6 groups may comprise branched alkandiyl or branched areniyl, and 80% to 100% of the R6 groups may be -(CH2)P-O-(CH2)q-O-(CH2)i~. In portions of Formula (7) and prepolymers of Formulas (7a)-(7b), a branched alkandiyl or a branched ring can be -R(-A)n-, where R is a hydrocarbon group, n is 1 or 2 and A is a branch point. A branched alkandiyl may have the structure -CH2(-CH(-CH2-)-)-. Examples of thiol-terminated polysulfide prepolymers of Formulas (7a) and (7b) are disclosed, for example, in US Application Publication No. 2016 / 0152775, US Patent No. 9,079,833 and US Patent No. #9,663,619. A polysulfide prepolymer may comprise a polysulfide prapolymer comprising a portion of Formula (8), a thiol-terminated polysulfide prepolymer of Formula (8a), a terminal-modified polysulfide prepolymer of Formula (8b) or a combination of any of the above: -(R7-O<H2-O-R7-Sm-)n-i-R7-CRCH2-O-R7-(8) HS-(R7-O-CH2-O-R7-Sm-)n-i-R7-O-CH2-O-R7-SH(8a) R3-S-(R7-O-CH2-O-R7-Sm-)n-i-R7-O-CH2-O-R7-S-R3(8b) where R7 is C2-4alkandiyl, m is an integer of 2 to 8 and n is an integer from 2 to 370; and each R3 is independently a moiety comprising a terminal reactive functional group.

[001] Portions of Formula (8) and prepolymers of Formulas (8a)-(8b) are disclosed, for example, in JP 62-53354. A sulfur-containing prepolymer may comprise a sulfur-containing polyformal prepolymer or a combination of sulfur-containing polyformal prepolymers. Sulfur-containing polyformal prepolymers useful in senator applications are disclosed, for example, in US Patent No. 8,729,216 and US Patent No. 8,541,513. A sulfur-containing polyformal prepolymer may comprise a portion of Formula (9), a thiol-terminated sulfur-containing polyformal prepolymer of Formula (9a), a terminally modified sulfur-containing polyformal prepolymer of Formula ( 9b), a thiol-terminated sulfur-containing polyformal prepolymer of Formula (9c), a terminally modified sulfur-containing polyformal prepolymer of Formula (9d), or a combination of any of the foregoing: -R8-(S)P-R8-[O-C(R9)2-O-R8-(S)P-R8-]n-(9) R10-R8-(S)p-R8-[O-C(R9)2-O-R8-(S)P-R8-]n-R10(9a) R3-R8-(S)p-R8-[O-C(R9)2-O-R8-(S)P-R8-]n-R3(9b) I br1 n / I 7Π7 / 3 / ΥΙΛΙ {R10-R8-(S)P-R8-[O-C(R9)2-O-R8-(S)P-R8-]n-O-C(R9)2-O-} mZ (9c) {R3-R8-(S)p-R8-[O-C(R9)2-O-R8-(S)p-R8-]n-O-C(R9)2-O-}mZ (9d) where n can be an integer from 1 to 50; each p can be selected independently of 1 and 2; each R8 can be C2-6alkandiyl; and each R9 can be independently selected from hydrogen, Ci-6 alkyl, C7-12 phenylalkyl, C7-12 substituted phenylalkyl, Ce-i2 cycloalkylalkyl, Ce-i2 substituted cycloalkylalkyl, C3-12 cycloalkyl, C3-i2 substituted cycloalkyl, C6-12 aryl and Ce-i2 substituted aryl; each R10 is a moiety comprising a terminal thiol group; and each R3 is independently a moiety comprising a terminal reactive functional group other than a thiol group; and Z may be derived from the nucleus of an m-valent parent polyol Z(OH)m. A sulfur-containing prepolymer can comprise a monosulfide prepolymer or a combination of monosulfide prepolymers. A monosulfide prepolymer may comprise a portion of Formula (10), a thiol-terminated monosulfide prepolymer of Formula (10a), a thiol-terminated monosulfide prepolymer of Formula (10b), a monosulfide prepolymer modified in the terminal of Formula (10c), a terminally modified monosulfide prepolymer of the I br1 η / I 7Π7 / 3 / ΥΙΛΙ Formula (lOd) or a combination of any of the above: - S-R13- [-S- (R11-X)P-(R12-X)q—R13- ]n-S-(10) HS-R13-[-S-(R11-X)P-(R12-X)q-R13-]n-SH(10a) {HS-R13-[-S-(R11-X)P-(R12- X)q-R13-]n-S-V'-}zB(10b) R3-S-R13-[-S-(Rn-X)P-(R12-X)q-R13-]n-S-R3(10c) {R3-S-R13-[-S-(Ru-X)p -(R12-X)q-R13-]n-S-V'-}zB(10d) wherein each R11 can be independently selected from C2-10 alkandiyl, such as C2-6 alkandiyl; C2-io branched alkandiyl, such as C3-6 branched alkandiyl or a C3-6 branched alkandiyl having one or more pendant groups which may be, for example, alkyl groups, such as methyl or ethyl groups; Ce-s cycloalkandiyl; G5-14 alkylcycloalkandiyl, such as Ce-io alkylcycloalkandiyl; and Cs-io alkylarendiyl; each R12 may be independently selected from C1-10 n-alkandiyl, such as Ci6 n-alkandiyl, C2-10 branched alkandiyl, such as C3-6 branched alkandiyl having one or more pendant groups which may be, for example, alkyl groups, such as methyl or ethyl groups; Ce-s cycloalkandiyl; Ce-14 alkylcycloalkandiyl, such as Ce-io alkylcycloalkandiyl; and Cs-io alkylarendiyl; each R13 may be independently selected from C1-10 n-alkandiyl, such as Ci6 n-alkandiyl, C2-10 branched alkandiyl, such as C3-6 branched alkandiyl having one or more pendant groups which may be, for example, alkyl groups, such as methyl or ethyl groups; Ce-s cycloalkandiyl group; Ce-w alkylcycloalkandiyl, such as a Ce-io alkylcycloalkandiyl; and Cs-io alkylarendiyl; each X can be selected independently of O and S; p can be an integer from 1 to 5; q can be an integer from 0 to 5; and n can be an integer from 1 to 60, such as 2 to 60, 3 to 60, or 25 to 35; each R3 is independently selected from a reactive functional group; B represents a core of an agent with z-valent polyfunctionality B(-V)zen where: z can be an integer from 3 to 6; and each V may be a moiety comprising a terminal group reactive with a thiol group; each -V- can be derived from the reaction of -V with a thiol. Methods for synthesizing thiol-terminated monosulfides comprising portions of Formula (10) or prepolymers of Formulas (10b)-(10c) are disclosed, for example, in US Patent No. 7,875,666. A monosulfide prepolymer may comprise a portion of Formula (11), a thiol-terminated monosulfide prepolymer comprising a portion of Formula (lia), comprise a thiol-terminated monosulfide prepolymer of Formula (11b), a prepolymer thiol-terminated monosulfide of Formula (11c), a thiol-terminated monosulfide prepolymer of Formula (lid), or a combination of any of the above: ηγ 1 n / Lznz / q / YiAi -[-S-(R14-X)P-C(R15)2-(X-R14)q-]n-S-(11) H-[-S-(R14-X)P-C(R15)2-(X-R14)q-]n-SH(lia) R3-[-S-(R14-X)P-C(R15)2-(X-R14)q-]n-S-R3(11b) {H-[-S-(R14-X)P-C(R15)2-( X-R14)q-]n-S-V'-}zB(11c) {R3-[-S-(R14-X)p-C(R15)2-(X-R14)q-]n-S-V'-}zB (lid) wherein each R14 can be independently selected from C2-10 alkandiyl, such as C2-6 alkandiyl; a C3-10 branched alkandiyl, such as a C3-6 branched alkandiyl or a C3-6 branched alkandiyl having one or more pendant groups which may be, for example, alkyl groups, such as methyl or ethyl groups; a Ce-8 cycloalkandiyl; a Οδ-κ alkylcycloalkandiyl, such as a Ce-io alkylcycloalkandiyl; and a Ce-io alkylarendiyl; each R15 may be independently selected from hydrogen, C1-10 n-alkandiyl, such as a C1-6 n-alkandiyl, C3-10 branched alkandiyl, such as a C3-6 branched alkandiyl having one or more pendant groups which may be, for example, alkyl groups, such as methyl or ethyl groups; a Οδ-s cycloalkandiyl group; a Οδ-κ alkylcycloalkandiyl, such as a Οδ-ίο alkylcycloalkandiyl; and a Cs-io alkylarendiyl; each X can be selected independently of O and S; p can be an integer from 1 to 5; q can be an integer from 1 to 5; n can be an integer from 1 to 60, such as 2 to 60, 3 to 60, or 25 to 35; each R3 is a moiety comprising a terminal functional group. B represents a core of an agent with z-valent polyfunctionality B(-V)zen where: z can be an integer from 3 to 6; and each V may be a moiety comprising a terminal group reactive with a thiol group; each -V- can be derived from the reaction of -V with a thiol. Methods for synthesizing monosulfides of Formulas (11)-(1 Id) are disclosed, for example, in US Patent No. 8,466,220. A prepolymer may comprise a terminally modified prepolymer such as a terminally modified sulfurol-containing prepolymer. Terminal-modified sulfur-containing prepolymers refer to sulfur-containing prepolymers comprising terminal reactive functional groups other than thiol groups. A terminal reactive functional group such as R3 can be selected from, for example, an alkenyl, alkynyl, epoxy, isocyanate, hydroxyl, amine, Michael acceptor, Michael donor, or other reactive functional group. A terminally modified sulfur-containing prepolymer can be prepared, for example, by reacting a thiol-terminated sulfur-containing prepolymer with a compound comprising a terminal functional group and a group reactive with a thiol group. Examples of suitable groups reactive with thiol groups include alkenyl groups, alkynyl groups, epoxy groups, Michael acceptor groups, and isocyanate groups. For example, an alkenyl-terminated sulfur-containing prepolymer can be prepared by reacting a polyalkenyl compound with a thiol-terminated sulfur-containing prepolymer, an epoxy-terminated sulfur-containing prepolymer can be prepared by reacting a polyepoxide with a thiol-terminated sulfur-containing prepolymer. containing thiol-terminated sulfur, an isocyanate-terminated sulfur-containing prepolymer can be prepared by reacting a polyisocyanate with a thiol-terminated sulfur-containing prepolymer, and a Michael acceptor-terminated sulfur-containing prepolymer can be prepared by reacting a polyfunctional Michael acceptor with a thiol-terminated sulfur-containing prepolymer. A coreactive composition may comprise a reactive monomer or a I br1 n / I 7Π7 / 3 / ΥΙΛΙ combination of reactive monomers. A co-reactive monomer can comprise functional groups reactive with a prepolymer and / or another monomer. A reactive monomer can have a molecular weight, for example, less than 1,000 Da, less than 800 Da, less than 600 Da, less than 500 Da, less than 400 Da, or less than 300 Da. A monomer may have a molecular weight, for example, from 100 Da to 1,000 Da, from 100 Da to 800 Da, from 100 Da to 600 Da, from 150 Da to 550 Da, or from 200 Da to 500 Da. A monomer may have a molecular weight greater than 100 Da, greater than 200 Da, greater than 300 Da, greater than 400 Da, greater than 500 Da, greater than 600 Da, or greater than 800 Da. A reactive monomer can have a reactive functionality of two or more, for example, 2 to 6, 2 to 5, or 2 to 4. A reactive monomer can have a functionality of 2, 3, 4, 5, or 6. A reactive monomer can have an average reactive functionality, for example, from 2 to 6, from 2 to 5, from 2 to 4, from 2 to 3, from 2.1 to 2.8 or from 2.2 to 2.6. A reactive monomer may comprise any suitable functional group such as, for example, a thiol, alkenyl, alkynyl, epoxy, isocyanate, Michael acceptor, Michael donor, hydroxyl, amine, silanol, polyalkoxysilyl, or other suitable reactive functional group. A reactive monomer may comprise, for example, a polythiol, a polyalkenyl, a polyalkynyl, a polyepoxide, a polyfunctional Michael acceptor, a polyfunctional Michael donor, a polyisocyanate, a polyol, a polyamine, a polyfunctional silanol, a polyalkoxysilyl polyfunctional, or a combination of any of the above. A monomer may comprise a sulfur-containing monomer. A sulfur-containing monomer may have a sulfur content, for example, from 0% by weight to 80% by weight, from 2% by weight to 75% by weight, from 5% by weight to 70% by weight, from % by weight to 65% by weight, from 15% by weight to 60% by weight, or from 20% by weight to 50% by weight, where the % by weight is a function of the total molecular weight of the monomer. A monomer may have a sulfur content, for example, greater than 0% by weight, greater than 10% by weight, greater than 20% by weight, greater than 30% by weight, greater than 40% by weight, greater than 50 % by weight, greater than 60% by weight, greater than 70% by weight or greater than 80% by weight, where the % by weight is a function of the total molecular weight of the monomer. A monomer may have a sulfur content, e.g. example, less than 80% by weight, less than 70% by weight, less than 60% by weight, less than 50% by weight, less than 40% by weight, less than 30% by weight, less than 20% by weight , less than 10% by weight, or less than 5% by weight, where the % by weight is a function of the total molecular weight of the monomer. A reactive monomer can comprise a polyfunctionalizing agent or a combination of polyfunctionalizing agents. Polyfunctionalizing agents may have functionality of three or more I br / n / I 7Π7 / 3 / ΥΙΛΙ functional groups that can be included in a composition to increase the crosslinking density of a cured polymeric matrix. A polyfunctionalizing agent may comprise functional groups reactive with reactive prepolymers and / or reactive monomers. A polyfunctionalizing agent may comprise an average functionality, for example, 3 to 6, such as 3 to 5, or 3 to 4. A polyfunctionalizing agent may have a functionality of 3, 4, 5, or 6. A polyfunctionalizing agent may comprise, for example, a polythiol, a polyalkenyl, a polyalkynyl, a polyepoxide, a polyfunctional Michael acceptor, a polyfunctional Michael donor, a polyisocyanate, a polyol, a polyamine, a polyfunctional silanol, a polyfunctional polyalkoxysilyl, or a combination of any of the above. A first reactive compound and a second reactive compound may each independently comprise at least two first functional groups and the second compound may comprise at least two second functional groups, where the second functional groups are reactive with the first functional groups. For example, the first functional group may be a thiol group, and the second functional group may be an alkenyl group, alkynyl group, epoxy group, Michael acceptor group, isocyanate group, or a combination of any of the foregoing. Functional groups and particular cure chemistries can be selected to provide a desired cure rate and / or to impart a desired property to a cured layer of a multilayer system. Examples of useful curing chemistries include hydroxyl / isocyanate, amine / isocyanate, epoxy / epoxy, and Michael acceptor / Michael donor reactions. Thus, a first functional group may comprise an isocyanate and a second functional group may comprise a hydroxyl group, an amine group, or a combination of these. A first functional group may comprise an amine group, and a second functional group may comprise an epoxy group. A first functional group may comprise an epoxy group, and a second functional group may comprise an epoxy group. A first functional group may comprise a Michael acceptor group, and a second functional group may comprise a Michael donor group. A first functional group can be a saturated functional group and the second functional group can be an unsaturated group. Each of the first functional group and the second functional group may comprise a saturated functional group. Each of the first functional group and the second functional group may comprise an unsaturated functional group. A saturated functional group I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ refers to a functional group and does not have a double bond. Examples of saturated functional groups include thiol, hydroxyl, primary amine, secondary amine, and epoxy groups. An unsaturated functional group refers to a group that has a reactive double bond. Examples of unsaturated functional groups include alkenyl groups, Michael acceptor groups, isocyanate groups, acyclic carbonate groups, acetoacetate groups, carboxylic acid groups, vinyl ether groups, (meth)acrylate groups, and malonate groups. A first functional group may be a carboxylic acid group, and the second functional group may be an epoxy group. The first functional group may be a Michael accept group such as a (meth)acrylate group, a maleic group or a fumaric group, and the second functional group may be a primary amine group or a secondary amine group. The first functional group may be an isocyanate group and the second functional group may be a primary amine group, a secondary amine group, a hydroxyl group or a thiol group. The first functional group can be a cyclic carbonate group, an acetoacetate group, or an epoxy group; and the second functional group can be a primary amine group, or a secondary amine group. The first functional group may be a thiol group and the second functional group may be an alkenyl group, a vinyl ether group, a (meth)acrylate group. The first functional group may be a Michael accept group such as a (meth)acrylate group, a cyanoacrylate, a vinylether, a vinylpyridine, or an α,β-unsaturated carbonyl group and the second functional group may be a malonate group, a acetylacetonate, a nitroalkane, or other active alkenyl group. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ The first functional group may be a thiol group and the second group may be an alkenyl group, an epoxy group, an isocyanate group, an alkynyl group, or Michael's accept. The first functional group may be a Michael donor group and the functional group may be a Michael acceptor group. functional a second group Both the first functional group and the second functional group can be thiol groups. Both the first functional group and the second functional group can be alkenyl groups. Both the first functional group and the second functional group can be Michael acceptor groups such as (meth)acrylate groups. For example, the first reactive compound may comprise a polyamine and / or polyol and the second reactive compound may comprise a polyisocyanate; the first reactive compound may comprise a Michael acceptor and the second reactive compound may comprise a Michael donor; or the first reactive compound may comprise a polythiol and the second reactive compound may comprise a polythiol, a polyisocyanate, a polyalkenyl, a polyalkynyl, a polyepoxide, a Michael acceptor, or a combination of any of the foregoing. The functional groups may be selected to coreact at temperatures, eg, less than 50°C, less than 40°C, less than 30°C, less than 20°C, or less than 10°C. The functional groups can be selected to coreact at temperatures, eg, greater than 5°C, greater than 10°C, greater than 20°C, greater than 30°C, or greater than 40°C. The functional groups can be selected to coreact, for example, at temperatures of 5°C to 50°C, 10°C to 40°C, 15°C to 35°C, or 20°C to 30°C. The cure rate for any of these coreactive chemistries can be modified by including an appropriate catalyst or combination of catalysts in a coreactive composition. The cure rate for any of these coreactive chemistries can be modified by increasing or decreasing the temperature of the coreactive composition. For example, while a coreactive composition can be cured at temperatures less than 30°C, such as below 25°C or below 20°C, heating the coreactive composition can speed up the rate of reaction, which may be desirable in certain situations. circumstances, such as for adaptation to a higher printing speed. Increasing the temperature of the coreactive components and / or the coreactive composition can also serve to adjust the viscosity to facilitate mixing of the coreactive components and / or deposition of the coreactive composition. To form a multi-coat system, it may be desirable for certain coats to cure faster than other coats. For example, it may be desirable for an outer layer to cure quickly to facilitate the ability of an applied multi-layer system to retain the desired shape, and for an inner layer to cure slowly to develop adhesion and / or desirable physical properties over time. Each of the coreactive compositions used to prepare one layer of a multilayer system may independently comprise, for example, one or more additives such as, for example, catalysts, polymerization initiators, adhesion promoters, reactive diluents, plasticizers, fillers. , colorants, photochromic agents, rheology modifiers, cure activators and accelerators, corrosion inhibitors, flame retardants, UV stabilizers, rain erosion inhibitors, or a combination of any of the foregoing. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ A coreactive composition may comprise one or more additives selected to impart one or more desired properties to a cured layer of a multilayer system. Examples of properties of a cured coating and additives to provide the properties to a coating are provided in the following paragraphs. A coreactive composition can include a catalyst or a combination of catalysts. A catalyst or a combination of catalysts may be selected to catalyze the reaction of coreactants in the coreactive composition, such as the reaction of the first coreactive compound and the second coreactive compound. The appropriate catalyst will depend on the curing chemistry. For example, an ene thiol or epoxy thiol may comprise an amine catalyst. A coreactive composition may comprise, for example, from 0.1% by weight to 1% by weight, from 0.2% by weight to 0.9% by weight, from 0.3% by weight to 0.7% by weight or from 0.4% by weight to 0.6% by weight of a catalyst or a combination of catalysts, where the % by weight is based on the total weight of the coreactive composition. A catalyst can include a latent catalyst or a combination of latent catalysts. Latent catalysts include catalysts that have little or no activity until released or activated, for example, by physical and / or chemical mechanisms. Latent catalysts may be within a structure or may be chemically locked. A controlled release catalyst can release a catalyst upon exposure to ultraviolet radiation, heat, ultrasound, or moisture. A latent catalyst can be sequestered within a core-shell structure or trapped within a crystalline or semi-crystalline polymer matrix where the catalyst can disperse from the encapsulating agent over time or upon activation, such as by application of thermal energy. or mechanical. A coreactive composition may comprise a dark cure catalyst or a combination of dark cure catalysts. A dark cure catalyst refers to a catalyst capable of generating free radicals without exposure to electromagnetic energy. Dark cure catalysts include, for example, combinations of metal complexes and organic peroxides, thialkylborane complexes, and peroxide-amine redox initiators. A dark cure catalyst can be used in conjunction with a photopolymerization initiator or independently of a photopolymerization initiator. A thiol / thiol curing chemistries-based coreactive composition may comprise a cure activator or a combination of cure activators to initiate the thiol / thiol polymerization reaction. The cure activators can be used, for example, in a coreactive composition in which the first reactive compound and the second reactive compound comprise thiol-terminated sulfur-containing prepolymers, such as prepolymers of I br1 n / I 7Π7 / 3 / ΥΙΛΙ polysulfide terminated in thiol. A cure activator may comprise an oxidizing agent capable of oxidizing mercaptan groups to form disulfide bridges. Examples of suitable oxidizing agents include lead dioxide, manganese dioxide, calcium dioxide, sodium perborate monohydrate, calcium peroxide, zinc peroxide, and dichromate. A cure activator can comprise an inorganic activator, an organic activator, or a combination of these. Examples of suitable inorganic activators include metal oxides. Examples of suitable metal oxide activators include zinc oxide (ZnO), lead oxide (PbO), lead peroxide (PbOs), manganese dioxide (MnO2), sodium perborate (NaBOs H2O), potassium permanganate ( KMnOi), calcium peroxide (CaCOs), barium peroxide (BaOs), eumene hydroperoxide, and combinations of any of the above. A cure trigger can be MnCh. A thiol / thiol curing chemistry-based coreactive composition may comprise, for example, from 1% by weight to 10% by weight of a cure activator or combination of cure activators, where the % by weight is a function of the total weight of the coreactive composition. For example, a coreactive composition may comprise from 1% by weight to 9% by weight, from 2% by weight to 8% by weight, from 3% by weight to 7% by weight or from 4% by weight to 6% by weight. weight of a cure activator or combination of activators, where the % by weight is based on the total weight of the coreactive composition. For example, a coreactive composition may comprise greater than 1% by weight of a cure activator or combination of cure activators, greater than 2% by weight, greater than 3% by weight, greater than 4% by weight, greater than 5% by weight or more than 6% by weight of a cure activator or a combination of cure activators, where the % by weight is based on the total weight of the coreactive composition. A thiol / thiol curing chemistry-based coreactive composition can include a cure accelerator or combination of cure accelerators. Cure accelerators can act as sulfur donors to generate active sulfur fragments capable of reacting with the thiol groups of a thiol-terminated polysulfide prepolymer. Examples of suitable cure accelerators include tlazoles, thiurams, sulfenamides, guanidines, dithiocarbamates, xanthates, thioureas, aldehydeamines, and combinations of any of the foregoing. A cure accelerator may comprise a thiuram polysulfide, a thiuram disulfide, or a combination of these. Examples of other suitable cure accelerators also include triazines. I br1 n / I 7Π7 / 3 / ΥΙΛΙ and metal and amine sulfides or salts of dialkyldithiophosphoric acids and dithiophosphates such as triazines and metal and amine sulfides or salts of dialkyldithiophosphoric acids, and combinations of any of the foregoing. Examples of non-sulfur curing accelerators include tetramethyl guanidine (TMG), di-o-tolyl guanidine (DOTG), sodium hydroxide (NaOH), water, and bases. A coreactive composition may comprise, for example, from 0.01% by weight to 2% by weight of a cure accelerator or combination of cure accelerators, from 0.05% by weight to 1.8% by weight, from 0.1% by weight to 1.6% by weight or from 0.5% by weight to 1.5% by weight of a cure accelerator or combination of cure accelerators, where the % by weight is a function of the total weight of the coreactive composition. A coreactive composition may comprise, for example, less than 2% by weight, less than 1.8% by weight, less than 1.6% by weight, less than 1.4% by weight, less than 1.2% by weight, less than 1% by weight , less than 0.5% by weight, less than 0.1% by weight or less than 0.05% by weight of a cure accelerator or combination of cure accelerators, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition may comprise one or more free radical initiators such as thermally activated free radical initiators or actinic radiation activated free radical initiators. A coreactive composition can be cured by actinic radiation such as a sealant composition based on thiol / alkenyl, thiol / alkynyl, and alkenyl / alkenyl curing chemistries. A coreactive composition that can be cured by visible or ultraviolet radiation may comprise a photopolymerization initiator or combination of photopolymerization initiators. A coreactive composition can include a photoinitiator or combination of photoindicators. The radiation may be actinic radiation which can apply energy effective to generate a kind of initiation from a photopolymerization initiator upon irradiation therewith and broadly includes a-rays, y-rays, X-rays, ultraviolet (UV) light including UVA spectra , UVA and UVC), visible light, blue light, infrared, near infrared or an electron beam. For example, the photoinitiator can be a UV photoinitiator. Examples of suitable UV photoindicators include a-hydroxyketones, benzophenone, a, a.-diethoxyacetophenone, 4,4-diethylaminobenzophenone, 2,2-dimethoxy¡-2-phenylacetophenone, 4-isopropylphenyl 2-hydroxy¡-2-prop ¡l ketone, 1-hydroxydclohexyl phenyl ketone, isoamyl p-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate, methyl D-benzoylbenzoate, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-hydroxy-2-methyl- lphenylpropan-l-one, 2-isopropylthioxanthone, dibenzosuberone, 2,4,67 I br1 n / I 7Π7 / 3 / ΥΙΛΙ trimethylbenzoyldiphenylphosphine oxide, bisacyclophosphine oxide, benzophenone photoinitiators, oxime photoinitiators, phosphine oxide photoinitiators, and combinations of any of the above. A coreactive composition may comprise from 0.05% by weight to 5% by weight, from 0.1% by weight to 4.0% by weight, from 0.25% by weight to 3.0% by weight, from 0.5% by weight to 1.5% by weight of a photoinitiator or combination of photoinitiators, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition may comprise a thermally active free radical initiator. A thermally active free radical initiator can be activated at elevated temperature, such as a temperature greater than 25°C. Examples of suitable thermally active free radical initiators include organic peroxy compounds, azobis(organonitrile) compounds, / Vacyloxyamine compounds, CMmino-isourea compounds, and combinations of any of the foregoing. Examples of suitable organic peroxy compounds that can be used as thermal polymerization initiators include peroxymonocarbonate esters, such as tertiary-butylperoxy 2-ethylhexyl carbonate and tertiary-butylperoxy isopropyl carbonate; peroxyketals, such as 1,1-di-Ctert-butyl peroxy)-3,3,5-trimethylcyclohexane; peroxycarbonate esters, such as d¡(2-ethylhexylperoxydicarbonate, di(secondary butyl)peroxydicarbonate and diisopropylperoxydicarbonate; diacylperoxides such as 2,4-didorobenzoyl peroxide, isobutyryl peroxide, decanoyl peroxide, lauryl peroxide, peroxide peroxide, acetyl peroxide, benzoyl peroxide, and p-chlorobenzoyl peroxide, peroxyesters such as tert-butylperoxy pivalate, tert-butylperoxy octylate, and tert-butylperoxyisobutyrate, methyl ethyl ketone peroxide, acetylcyclohexane sulfonyl peroxide, and combinations of any of the foregoing. Other examples of suitable peroxy compounds include 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane and / or 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane Examples of azobis compounds Suitable (organonitrile) compounds that can be used as thermal polymerization initiators include azobis(isobutyronitrile), 2,2'-azobis(2-methyl-butanenitrile) and / or azobis(2 / 4-dimethylvaleronitrile). Thermally active free radical initiator may comprise l-acetox¡-2,2,6,6-tetramethylpiperidine and / or ES-dicylohexyl-CKAA cyclohexylideneaminoj-isourea. A coreactive composition can comprise an adhesion promoter or a combination of adhesion promoters. Adhesion promoters can improve the adhesion of a sealant to an underlying substrate such as a metal, composite, polymeric, or ceramic surface, or to a coating such as a primer coat or other topcoat. Adhesion promoters can improve adhesion to filler and other layers in a multi-coat system. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ An adhesion promoter can include a phenolic adhesion promoter, a combination of phenolic adhesion promoters, an organofunctional silane, a combination of organofunctional silanes, or a combination of any of the foregoing. An organofunctional alkoxysilane may be an amine functional alkoxysilane. The organic group can be selected from, for example, a thiol group, an amine group, an epoxy group, an alkenyl group, an isocyanate group or a Michael accept group. A phenolic adhesion promoter may comprise a baked phenolic resin, an unbaked phenolic resin, or a combination of these. Examples of suitable adhesion promoters include phenolic resins, such as Methylon® phenolic resin, and organosilanes, such as epoxy-, mercapto-, or amine-functional silanes, such as Silquest® organosilanes. A baked phenolic resin refers to a phenolic resin that has been coreacted with a monomer or prepolymer. A phenolic adhesion promoter may comprise the reaction product of a condensation reaction of a phenolic resin with one or more thiol-terminated polysulfides. Phenolic adhesion promoters may be thiol terminated. Examples of suitable phenolic resins include those synthesized from 2(hydroxymethyl)phenol, (4-hydroxy-1,3-phenylene)dimethanol, (2-hydroxybenzene-1,3,4-triyl)trimethanol, 2benzyl-6- (Hydroxmethyl)phenol, (4-Hydroxy-5-((2-Hydroxy-5-(Hydroxymethyl)c-clohexa-2,4-dyen-l -¡l)methyl)l,3-phenylene)dimethanol, (4-hydroxy-5-((2-hydroxy-3,5-bis(hydroxymethyl)cyclohexa-2,4-dien-l-yl)methyl )-1,3-phenylene)dimethanol and a combination of any of the above. Suitable phenolic resins can be synthesized by the base-catalyzed reaction of phenol with formaldehyde. Phenolic adhesion promoters may comprise the reaction product of a condensation reaction of a Methylon® resin, a Varcum® resin or a Durez® resin available from Durez Corporation with a thiol-terminated polysulfide such as a Thioplast® resin. Examples of Methylon® resins include Methylon® 75108 (methylol phenol allyl ether, see US Patent No. 3,517,082) and Methylon® 75202. Examples of Varcum® resins include Varcum® 29101, Varcum® 29108, Varcum® 29112, Varcum® 29116, Varcum® 29008, Varcum® 29202, Varcum® 29401, Varcum® 29159, Varcum® 29181, Varcum® 92600, Var Cum® 94635 , Varcum® 94879 and Varcum® 94917. An example of a Durez® resin is Durez® 34071. A coreactive composition may comprise an organofunctional alkoxysilane adhesion promoter such as an organofunctional alkoxysilane. An organofunctional alkoxysilane may comprise hydrolyzable groups attached to a silicon atom and at least one I br1 n / I 7Π7 / 3 / ΥΙΛΙ organofunctional group. An organofunctional alkoxysilane may have the structure R20-(CH2)n-Si(-OR)3-nRn, where R20 is an organofunctional group, n is 0, 1 or 2, and R is alkyl such as methyl or ethyl. Examples of organofunctional groups include epoxy, amino, methacryloxy, or sulfide groups. An organofunctional alkoxysilane can be a dipodal alkoxysilane having two or more alkoxysilane groups, a functional dipodal alkoxysilane, a non-functional dipodal alkoxysilane, or a combination of any of the foregoing. An organofunctional alkoxysilane can be a combination of a monoalkoxysilane and a dipodal alkoxysilane. For amino-functional alkoxysilanes, R20 can be -NH2, Examples of suitable Silquest® brand amino-functional alkoxysilanes include γ-aminopropyltriethoxysilane (Silquest® A-1100), γ-aminopropylsesquioxane (Silquest® A-1108), γ-aminopropyltrimethoxysilane (Silquest® A-1110), N-p-( aminoethyl)-Yaminopropyltrimethoxysilane (Silquest® 1120), benzylamino-silane (Silquest® 1128), triaminofunctional silane (Silquest® A-1130), bis-(Y-triethoxysilylpropyl)amine (Silquest® Y-11699), bis-(Ytrimethoxysilpropyl)amine (Silquest® A-1170) polyazamide (Silquest® A-1387), ethoxy-based polyazamide (Silquest® Y-19139), and N-p-(aminoethyl)-Y-aminopropylmethyldimethoxysilane (Silquest® A2120). Suitable amine-functional alkoxysilanes are commercially available, for example, from Gelest Inc, through Dow Corning Corporation and Momentive. A coreactive composition may comprise, for example, from 1% by weight to 16% by weight of an adhesion promoter, from 3% by weight to 14% by weight, from 5% by weight to 12% by weight, or from 7 % by weight to 10% by weight of an adhesion promoter or of a combination of adhesion promoters, where the % by weight is based on the total weight of the co-reactive composition. A coreactive composition may comprise less than 16% by weight of an adhesion promoter, less than 14% by weight, less than 12% by weight, less than 10% by weight, less than 8% by weight, less than 6% by weight, less than 4% by weight or less than 2% by weight of an adhesion promoter or a combination of adhesion promoters, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition for forming a layer of a multilayer system may comprise a filler or a combination of fillers. A filler may comprise, for example, an inorganic filler, an organic filler, a low-density filler such as a filler having a specific gravity of less than 1, a conductive filler, or a combination of any of the above. A coreactive composition for forming a multilayer system may comprise an inorganic filler or a combination of inorganic fillers. I br1 n / I 7Π7 / 3 / ΥΙΛΙ An inorganic filler may be included, for example, to provide mechanical reinforcement and to control the rheological properties of the composition. Inorganic filler may be added to the compositions to impart desirable physical properties such as, for example, to increase impact resistance, to control viscosity, or to modify the electrical properties of a coreactive composition. Inorganic fillers useful in a sealant composition include carbon black, calcium carbonate, precipitated calcium carbonate, calcium hydroxide, hydrated alumina (aluminum hydroxide), talc, mica, titanium dioxide, alumina silicate, carbonates, chalk, silicates, silica, glass, metal oxides, graphite, and combinations of any of the foregoing. Suitable calcium carbonate filler may include products such as Socal® 31, Socal® 312, Socal® U1S1, Socal® UaS2, Socal® N2R, Winnofil® SPM and Winnofil® SPT available from Solvay Special Chemicals. A calcium carbonate filler can include a combination of precipitated calcium carbonates. The inorganic filler can be surface treated to provide hydrophobic or hydrophilic surfaces that can facilitate dispersion and compatibility of the inorganic filler with other components of a coreactive composition. An inorganic filler may include surface modified particles such as, for example, surface modified silica. The surface of the silica particles can be modified, for example, to match the hydrophobicity or hydrophilicity of the silica particle surface. Surface modification can affect particle dispensability, viscosity, cure rate, and / or adhesion. A coreactive composition can comprise an organic filler or a combination of organic fillers. An organic filler can be selected to have a low specific gravity and to be resistant to solvents such as JRF Type I and / or to reduce the density of a layer. A suitable organic filler may also have acceptable adhesion to the sulfur-containing polymer matrix. An organic filler can include solid particles or powders, hollow particles or powders, and combinations thereof. An organic filler may have a specific gravity, for example, less than 1.15, less than 1.1, less than 1.05, less than 1, less than 0.95, less than 0.9, less than 0.8, or less than 0.7. An organic filler may have a specific gravity, for example, within the range of 0.85 to 1.15, within the range of 0.9 to 1.1, within the range of 0.9 to 1.05, or 0.85 to 1.05. An organic filler can comprise thermoplastics, thermosets, or a combination of these. Examples of suitable thermoplastics and thermosets include I br1 n / L7n7 / q / YIAI epoxies, epoxy-amides, ethylene tetrafluoroethylene copolymers, nylons, polyethylenes, polypropylenes, polyethylene oxides, polypropylene oxides, polyvinylidene chlorides, polyvinylfluorides, tetrafluoroethylene, polyamides, polyimides, ethylene propylenes , perfluorohydrocarbons, fluoroethylenes, polycarbonates, polyetheretherketones, polyetherketones, polyphenylene oxides, polyphenylene sulfides, polystyrenes, polyvinyl chlorides, melamines, polyesters, phenolics, epichlorohydrins, fluorinated hydrocarbons, polycidics, polybutadienes, polychloroprenes, polyisoprenes, polysulfides, polyurethanes , isoprenes of isobutylene, silicones, styrene butadienes, liquid crystal polymers, and combinations of any of the foregoing. Examples of suitable polyamide 6 and polyamide 12 particles are available from Toray Plastics as grades SP-500, SP-10, TR-1 and TR-2. Suitable polyamide powders are also available from Arkema Group under the tradename Orgasol® and from Evonik Industries under the tradename Vestosin®. An organic filler can be in any suitable form. For example, an organic filler may comprise fractions of ground polymer that have been filtered to select a desired size range. An organic filler may comprise substantially spherical particles. The particles can be solid or porous. An organic filler may have an average particle size, for example, within a range of 1 pm to 100 pm, 2 pm to 40 pm, 2 pm to 30 pm, 4 pm to 25 pm, 4 pm to 8 pm, from 2 pm to 12 pm or from 5 pm to 3 pm. An organic filler may have an average particle size, for example, less than 100 pm, less than 75 pm, less than 50 pm, less than 40 pm, or less than 20 pm. Particle size distribution can be determined by use of a Fisher Sub-Sieve Sizer or by optical inspection. An organic filler may include a low density agent, such as an expanded and modified thermoplastic microcapsule. Suitable expanded and modified thermoplastic microcapsules may include an outer coating of a melamine or urea / formaldehyde resin. A coreactive composition may comprise low density microcapsules. A low density microcapsule may comprise a thermally expanded microcapsule. A thermally expanded microcapsule refers to a hollow shell comprising a volatile material that expands at a predetermined temperature. Thermally expanded thermoplastic microcapsules can have an average initial particle size of 5 pm to 70 pm, in some cases, 10 pm to 12 pm or 10 pm to 5 pm. The term "average initial particle size" refers to the average particle size (numerical weighted average of the particle size distribution) of the microcapsules before any expansion. The particle size distribution can be determined I br1 n / I 7Π7 / 3 / ΥΙΛΙ by using a Fisher Sub-Sieve Sizer or by optical inspection. Examples of materials suitable for forming the wall of the thermally expanded microcapsule include polymers of vinylidene chloride, acrylonitrile, styrene, polycarbonate, methyl methacrylate, ethyl acrylate, and vinyl acetate, copolymers of these monomers, and combinations of the polymers and copolymers. . A crosslinking agent can be included with the materials that form the wall of a thermally expanded microcapsule. Examples of suitable thermoplastic microcapsules include Expancel™ microcapsules, such as Expancel™ DE microspheres available from AkzoNoel. Examples of suitable Expancel™ DE microspheres include Expancel™ 920 DE 40 and Expancel™ 920 DE 80. Low density microcapsules are also available from Kureha Corporation. The low density filler, such as low density microcapsules, can be characterized by a specific gravity within a range of 0.01 to 0.09, from 0.04 to 0.09, within a range of 0.04 to 0.08, within a range of 0.01 to 0.07, within a range of 0.02 to 0.06, within a range of 0.03 to 0.05, within a range of 0.05 to 0.09, 0.06 to 0.09, or within a range of 0.07 to 0.09, where the specific gravity is determined according to ISO 787-11. The low density filler, such as low density microcapsules, may be characterized by a specific gravity of less than 0.1, less than 0.09, less than 0.08, less than 0.07, less than 0.06, less than 0.05, less than 0.04, less of 0.03 or less than 0.02, where the specific gravity is determined in accordance with ISO 787-11. The low density filler, such as low density microcapsules, may be characterized by an average particle diameter of 1 pm to 100 pm and may have a substantially spherical shape. A substantially spherical particle may have a maximum transverse dimension less than the minimum transverse dimension of a particle of a low density filler, such as low density microcapsules, may be characterized, for example, by a mean particle diameter of 10 pm to 100 pm, 10 pm to 60 pm, 10 pm to 40 pm, or 10 pm to 30 pm, determined in accordance with ASTM D6913. The low density filler, such as low density microcapsules, may comprise microcapsules or expanded microglobules having a coating of an aminoplast resin, such as a melamine resin. Particles coated with aminoplast resin were described in, for example, US Patent No. 8,993,691. Such microcapsules can be formed by heating a microcapsule comprising a blowing agent surrounded by a thermoplastic shell. Uncoated low density microcapsules can be reacted with an aminoplast resin, such as a urea / formaldehyde resin, to provide a thermosetting resin coating on the outer surface of the capsule. I br / n / I 7Π7 / 3 / ΥΙΛΙ particle. With the coating of an aminoplast resin, an aminoplast-coated microcapsule can be characterized by a specific gravity, for example, within a range of 0.02 to 0.08, within a range of 0.02 to 0.07, within a range of 0.02 to 0.06 , within a range of 0.03 to 0.07, within a range of 0.03 to 0.065, within a range of 0.04 to 0.065, within a range of 0.045 to 0.06 or within a range of 0.05 to 0.06, where gravity specific is determined in accordance with ISO 787-11. A coreactive composition may comprise micronized oxidized polyethylene homopolymer. An organic filler may include a polyethylene, such as an oxidized powdered polyethylene. Suitable polyethylenes are available, for example, from Honeywell International, Inc. under the tradename ACumist®, from INEOS under the tradename Eltrex®, and Mitsui Chemicals America, Inc. under the tradename Mipelon®. A coreactive composition may comprise, for example, from 1% by weight to 90% by weight of low density filler, from 1% by weight to 60% by weight, from 1% by weight to 40% by weight, of 1% by weight to 20% by weight, from 1% by weight to 10% by weight or from 1% by weight to 5% by weight of low density filler, where the % by weight is based on the total weight of the corrective composition. A coreactive composition may comprise more than 1% by weight of low density filler, more than 1% by weight, more than 2% by weight, more than 3% by weight, more than 4% by weight, more than 6 % by weight or more than 10% by weight of low density filler, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition may comprise from 1% by volume to 90% by volume of low density filler, from 5% by volume to 70% by volume, from 10% by volume to 60% by volume, from 20% by volume to 50% by volume or from 30% by volume to 40% by volume of low density filler, where the % by volume is a function of the total volume of the coreactive composition. A coreactive composition may comprise more than 1% by volume of low density filler, more than 5% by volume, more than 10% by volume, more than 20% by volume, more than 30% by volume, more than 40 % by volume, more than 50% by volume, more than 60% by volume, more than 70% by volume or more than 80% by volume of low density filler, where the % by volume is based on the total volume of the corrective composition. A coreactive composition can include a conductive filler or a combination of catalysts. A conductive filler may include an electrically conductive filler, semiconductive filler, thermally conductive filler I br1 n / I 7Π7 / 3 / ΥΙΛΙ conductive filler, magnetic filler, EMI / RFI shielding filler, static dissipative filler, electroactive filler, or a combination of any of the above. EMI / RFI shielding effectiveness can be determined in accordance with ASTM D4935. A coreactive composition can comprise an electrically conductive filler or a combination of different electrically conductive fillers. To make a cured layer electrically conductive, the concentration of an electrically conductive filler can be above the threshold for electrical percolation, where a conductive network of electrically conductive particles is formed. Once the electrical percolation threshold has been reached, the increase in conductivity as a function of filler charge can be modeled by a simple power law expression: Oc = Of (φ - φε)ι EQN. 1 where φ is the volume fraction of filler, φε is the percolation threshold, or is the conductivity of the filler, φ is the conductivity of the compound, and t is a scale component. The filler need not be in direct contact for current to flow, and conduction can take place through tunnels between the thin layers of binder surrounding the electrically conductive filler particles, and this resistance to Tunneling may be the limiting factor in the conductivity of an electrically conductive layer. A conductive filler may have any suitable shape and / or dimensions. For example, an electrically conductive filler may be in the form of particles, powders, flakes, platelets, filaments, fibers, crystals, or a combination of any of the foregoing. A conductive filler may comprise a combination of conductive filler with different shapes, different dimensions, different properties such as, for example, different thermal conduction, electrical conduction, magnetic permittivity, electromagnetic properties, or a combination of any of the foregoing. . A conductive filler may be a solid or may be in the form of a substrate such as a particle having a coating of a conductive material. For example, a conductive filler can be a low density microcapsule having an outer conductive coating. Examples of a suitable conductive filler, such as an electrically conductive filler, include metals, metal alloys, conductive oxides, semiconductors, carbon, carbon fiber, and combinations of any of the foregoing. Other examples of the electrically conductive filler include electrically conductive filler based on noble metals, such as pure silver; noble metals coated with noble metals, such as gold coated with silver; seminoble metals I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ coated with noble metals such as copper, nickel or silver-coated aluminium, for example silver-coated aluminum core particles or platinum-coated copper particles; glass, plastic or ceramic coated with noble metals, such as silver-coated glass microspheres, noble metal-coated aluminum or noble metal-coated plastic microspheres; mica coated with noble metals; and other such noble metal conductive filler. Seminoble metal-based materials can also be used and these include, for example, seminoble metals coated with seminoble metals, such as copper-coated iron particles or nickel-coated copper; seminoble metals, eg copper, aluminum, nickel, cobalt; nonmetals coated with seminoble metals, eg, nickel-coated graphite, and nonmetallic materials such as carbon black and graphite. Combinations of electrically conductive filler and forms of electrically conductive filler may be used to achieve a desired conductivity, EMI / RFI shielding effectiveness, and toughness, as well as other properties suitable for a particular application. The amount and type of electrically conductive filler can be selected to produce a coreactive composition that, when cured, exhibits a sheet resistance (four point resistance) of less than 0.50 Ω / cm2, or a sheet resistance of less than of 0.15 Ω / cm2. The amount and type of filler can also be selected to provide effective EMI / RFI shielding in a frequency range of 1 MHz to 18 GHz for a sealed opening through the use of a multilayer composition provided by the present disclosure. The organic filler, the inorganic filler and the low density filler can be coated with a metal to provide a conductive filler. An electrically conductive filler may include graphene. Graphene comprises a densely packed honeycomb crystal lattice made of carbon atoms having a thickness equal to the atomic size of a carbon atom, ie, a monolayer of sp2-hybridized carbon atoms arranged in a two-dimensional lattice. The graphene may comprise graphene carbon particles. Graphenic carbon particles refer to carbon particles having structures comprising one or more layers of one-atom-thick flat sheets of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. An average number of stacked layers may be less than 100, for example less than 50. An average number of stacked layers may be 30 or less, such as 20 or less, 10 or less, or in some cases 5 or less . Graphene carbon particles can be substantially planar, however, by I 1 n / I 7Π7 / 3 / ΥΙΛΙ except that a part of the flat sheets may be substantially curved, curled, wrinkled or bent. Graphenic carbon particles do not usually have a spheroidal or equiaxed morphology. The graphene carbon particles may have a thickness, measured in a direction perpendicular to the layers of carbon atoms, for example, of not more than 10 nm, not more than 5 nm, or not more than 4o3o2ol nm, such as not more than 3.6nm. Graphenic carbon particles can be from 1 atom layer to 3, 6, 9, 12, 20 or 30 atom layers thick, or more. The graphene carbon particles may have a width and length, measured in a direction parallel to the layers of carbon atoms, of at least 50 nm, such as greater than 100 nm, greater than 100 nm up to 500 nm, or greater than 100nm up to 200nm. The graphene carbon particles can be provided in the form of ultra-thin flakes, platelets, or sheets having relatively high aspect ratios, where the aspect ratio is the ratio of the longest dimension of a particle to the shortest dimension of the particle. , greater than 3:1, such as greater than 10:1. Graphenic carbon particles may comprise exfoliated graphite and have different characteristics compared to thermally produced graphenic carbon particles, such as different size distributions, thicknesses, aspect ratios, structural morphologies, oxygen contents, and chemical functionalities in the planes / basal border. The graphene carbon particles can be functionalized. Functionalized graphene carbon particles refer to graphene carbon particles in which organic groups are covalently attached to the graphene carbon particles. Graphenic carbon particles can be functionalized by forming covalent bonds between the carbon atoms of a particle and other chemical moieties such as carboxylic acid groups, sulfonic acid groups, hydroxyl groups, halogen atoms, nitro groups, amine groups. , aliphatic hydrocarbon groups, phenyl groups and the like. For example, functionalization with carbonaceous materials can lead to the formation of carboxylic acid groups on the graphene carbon particles. Graphenic carbon particles can also be functionalized by other reactions, such as Diels-Alder addition reactions, 1,3-dipolar cycloaddition reactions, free radical addition reactions, and diazonium addition reactions. Hydrocarbon groups and phenyl can be further functionalized. In the case of graphene carbon particles having hydroxyl functionality, the hydroxyl functionality can be modified and amplified by reacting these groups with, for example, an organic isocyanate. Different types of graphenic carbon particles can be used in a coreactive composition. I ΗΓ1 n / LZnZ / q / ΥΙΛΙ A coreactive composition may comprise, for example, 2 to 50% by weight, 4 to 40% by weight, 6 to 35% by weight, or 10 to 30% by weight of thermally produced graphene carbon particles. The filler used to impart electrical conductivity and EMI / RFI shielding effectiveness can be used in combination with graphene. Electrically conductive non-metallic filler, such as carbon nanotubes, carbon fibers, such as graphitized carbon fibers, and electrically conductive carbon black, can also be used in a coreactive composition in combination with the graphene. The conductive filler may comprise magnetic filler or a combination of magnetic fillers. The magnetic filler may include a soft magnetic metal. This can improve the permeability of a magnetic resin cast. At least one magnetic material selected from Fe, Fe-Co, Fe-N¡, Fe-Al, and Fe-Si can be used as a main component of the soft magnetic metal. A magnetic filler may be a soft magnetic metal having a high volumetric permeability. At least one magnetic material selected from Fe, FeCo, FeNi, FeAl and FeSi can be used as the soft magnetic metal. Specific examples include a Permalloy (FeNi alloy), a super Permalloy (FeNiMo alloy), a sendust (FeSiAl alloy), a FeSi alloy, a FeCo alloy, a FeCr alloy, a FeCrSi alloy, a FeNiCo and Fe alloy. Other examples of magnetic filler include iron-based powder, iron-nickel-based powder, iron powder, ferrite powder, alnico powder, Sm2Coi7 powder, Nd-B-Fe powder, BaFe2Oi barium ferrite, bismuth BÍFEOs, chromium dioxide CrCh, SmFeN, NdFeB and SmCo. A surface of the magnetic filler may be coated with insulation or may have a film thickness of the insulation coating equal to or greater than 10 nm. A surface of the magnetic filler may be coated with insulation with a metal oxide such as Si, Al, Ti, Mg or an organic material to improve the flowability, adhesion and performance of the insulation. Examples of carbonaceous materials suitable for use as a conductive filler other than graphene and graphite include, for example, graphitized carbon black, carbon fibers and fibrils, steam-grown carbon nanofibers, metal-coated carbon fibers, carbon nanotubes, including single and multi-walled nanotubes, fullerenes, activated carbon, carbon fibers, expanded graphite, expanded graphite, graphite oxide, hollow carbon spheres, and carbon foams. I 1 Π / I 7Π7 / 3 / ΥΙΛΙ The conductive filler may include semiconductors or combinations of semiconductors. Examples of suitable semiconductor materials include semiconductor nanomaterials such as nanoparticles, nanorods, nanowires, nanotubes, and nanosheets, semiconductor metal oxides such as tin oxide, antimony oxide, and indium oxide, semiconductor polymers such as PEDOT: PSS, polythiophenes, poly(sulfide) p-phenylene), polyanilines, poly(pyrrole), poly(acetylene), poly(p-phenylene vinylene), polyparaphenylene, any other conjugated polymers and small semiconductor molecules, e.g. with a molecular mass less than 5,000 Da, such such as rubrene, pentacene, anthracene and aromatic hydrocarbons. Examples of semiconductor nanomaterials are quantum dots, III-V or II-VI semiconductors, Si, Ge, transition metal dichalcogenides such as WS2, WSe2, and MoSes, graphene nanoribbons, semiconducting carbon nanotubes, and fullerenes and derivatives of fullerene. A filler can include metallic fibers such as steel, titanium, aluminum, gold, silver, and alloys of any of the foregoing. Examples of suitable ceramic fiber include metal oxide such as alumina fibers, aluminum silicate fibers, boron nitride fibers, silicon carbide fibers, and combinations of any of the foregoing. Examples of suitable inorganic fibers include carbon, alumina, basalt, calcium silicate, and rock wool. A fiber may be a glass fiber, such as S glass fibers, E glass fibers, soda-lime-silicon fibers, basalt fibers, or quartz fibers. The glass fibers may be in the form of woven and / or braided glass fibers, or non-woven glass fibers. A fiber can include carbon, such as graphite fibers, glass fibers, ceramic fibers, silicon carbide fibers, polyimide fibers, pollen fibers, or polyethylene fibers. Continuous fibers may comprise titanium, tungsten, boron, shape memory alloy, graphite, silicon carbide, boron, aramid, poly(p-phenylene-2,6-benzobisoxazole), and combinations of any of the foregoing. Fibers capable of withstanding high temperatures include, for example, carbon fiber, high-strength (S¡O2) glass fiber, oxide fiber, alumina fiber, ceramic fiber, metal fiber, and high-temperature thermoset or thermoplastic fibers. . A filler may include carbon nanotubes. Suitable carbon nanotubes can be characterized by a thickness or length, for example, from 1 nm to 5,000 nm. Suitable carbon nanotubes can be cylindrical in shape and structurally related to fullerenes. Suitable carbon nanotubes can be open or I 1 n / I 7Π7 / 3 / ΥΙΛΙ capped at their ends. Suitable carbon nanotubes may comprise, for example, greater than 90% by weight, greater than 95% by weight, greater than 99% by weight or greater than 99.9% by weight of carbon, where the % by weight based on the weight total carbon nanotube. Carbon nanotubes can be provided as single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs), for example, as nanotubes having a single wall and nanotubes having more than one wall, respectively. In single-walled nanotubes, a one-atom-thick sheet of atoms—for example, a one-atom-thick sheet of graphite—that is, graphene—is rolled seamlessly to form a cylinder. Multi-walled nanotubes consist of a number of such concentrically arranged cylinders. A multi-walled carbon nanotube can have, for example, an average of 5 to 15 walls. Single-walled nanotubes can be characterized as having a diameter of at least 0.5 nm, for example at least 1 nm, or at least 2 nm. A SWNT may have a diameter less than 50 nm, such as for example less than 30 nm, or less than 10 nm. A length of single-walled nanotubes can be at least 0.05 pm, at least 0.1 pm, or at least 1 pm. A length may be less than 50mm, such as for example less than 25mm. Multi-walled nanotubes can be characterized by an outer diameter of at least 1 nm, such as for example at least 2 nm, 4 nm, 6 nm, 8 nm or at least 9 nm. The outer diameter can be less than 100 nm, less than 80 nm, 60 nm, 40 nm, or less than 20 nm. The outer diameter can be from 9 nm to 20 nm. A length of a multi-walled nanotube may be less than 50 nm, less than 75 nm, or less than 100 nm. A longitude can be less than 500 pm, or less than 100 pm. A length can be from 100 nm to 10 pm. A multi-walled carbon nanotube can have a mean outer diameter of 9 nm to 20 nm and / or a mean length of 100 nm to 10 pm. Carbon nanotubes can have a BET surface area, for example, from 200 m2 / g to 400 m2 / g. Carbon nanotubes can have an average number of 5 walls to 15 walls. BET surface can be determined in accordance with ASTM D6556 A coreactive composition may comprise a heat conductive filler or a combination of heat conductive agents. A heat conductive filler may include, for example, metal nitrides such as boron nitride, silicon nitride, aluminum nitride, boron arsenide, carbon compounds such as diamond, graphite, carbon black, carbon fibers, graphene, and graphenic carbon particles, metal oxides such as aluminum oxide, magnesium oxide, beryllium oxide, silicon dioxide, titanium oxide, nickel oxide, zinc oxide, copper oxide, tin oxide, metal hydroxides such as aluminum or magnesium hydroxide, carbides I 1 n / I 7Π7 / 3 / ΥΙΛΙ such as silicon carbide, minerals such as agate and emery, ceramics such as ceramic microspheres, mullite, silica, silicon carbide, iron carbonite, certa(III) molybdate, copper, zinc or combinations of any of the above. A coreactive composition may comprise more than 5% by weight of a conductive filler, more than 10% by weight, more than 20% by weight, more than 30% by weight, more than 40% by weight, more than 50% by weight, more than 60% by weight, more than 70% by weight, more than 80% by weight, more than 90% by weight or more than 95% by weight of a conductive filler, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition may comprise less than 5% by weight of a conductive filler, less than 10% by weight, less than 20% by weight, less than 30% by weight, less than 40% by weight, less than 50% by weight, less than 60% by weight, less than 70% by weight, less than 80% by weight, less than 90% by weight or less than 95% by weight of a conductive filler, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition provided by the present disclosure may have from 1% by weight to 95% by weight of a conductive filler, from 5% by weight to 75% by weight, from 10% by weight to 60% by weight, or from 20% by weight to 50% by weight of a conductive filler, where % is based on the total weight of the coreactive composition. A coreactive composition may comprise less than 5% by volume of a conductive filler, less than 10% by volume, less than 20% by volume, less than 30% by volume, less than 40% by volume, less than 50% by volume, less than 60% by volume, less than 70% by volume, less than 80% by volume, less than 90% by volume, or less than 95% by volume of a conductive filler, where % by volume is as a function of the total volume of the corrective composition. A coreactive composition may comprise less than 5% by volume of a conductive filler, less than 10% by volume, less than 20% by volume, less than 30% by volume, less than 40% by volume, less than 50% by volume, less than 60% by volume, less than 70% by volume, less than 80% by volume, less than 90% by volume, or less than 95% by volume of a conductive filler, where % by volume is as a function of the total volume of the corrective composition. A coreactive composition provided by the present disclosure may have from 1% by volume to 95% by volume of a conductive filler, from 5% by volume to 75% by volume, from 10% by volume to 60% by volume, or from 20% by volume to 50% by volume of a conductive filler, where the % by volume is a function of the total volume of the coreactive composition. A coreactive composition may comprise a reactive diluent or a combination of reactive diluents. A reactive diluent can be used to reduce the I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ initial viscosity of the coreactive composition. A reactive diluent can be a compound having at least one functional group capable of reacting with at least one of the main reactants of the composition and forming part of the crosslinked network. A reactive diluent may have, for example, one functional group, or two functional groups. A reactive diluent can be used to control the viscosity of a composition or improve wetting of the filler in a coreactive composition. A coreactive composition may comprise a hydroxyl-functional vinyl ether or a combination of hydroxyl-functional vinyl ethers as reactive diluents. A hydroxyl-functional vinyl ether may have the structure of Formula (12): CH2=CH-O-(CH2)w-OH (12) where w is an integer from 2 to 10. In the hydroxyl-functional vinyl ethers of Formula (12), w can be 2, 3, 4, 5, or w may be 6. Examples of suitable hydroxyl-functional vinyl ethers are 1-methyl-3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, and a combination of these. A hydroxyl-functional vinyl ether may be 4-hydroxybutyl vinyl ethers as reactive diluents. A coreactive composition may comprise, for example, from 0.1% by weight to 10% by weight of a hydroxyl-functional vinyl ether, from 0.2% by weight to 9% by weight, from 0.3% by weight to 0.7% by weight and from 0.4% by weight to 0.7% by weight, where the % by weight is a function of the total weight of the coreactive composition. A coreactive composition may comprise an amino-functional vinyl ether or a combination of amino-functional vinyl ethers. An amino-functional vinyl ether may have the structure of Formula (13): CH2=CH-O-(CH2)t-NH2(13) where t is an integer from 2 to 10. In the amino-functional vinyl ethers of Formula (13), t can be 2, 3, 4, 5, or t it may be 6. Examples of suitable amino-functional vinyl ethers include 1-methyl-3-aminopropyl vinyl ether, 4-aminobutyl vinyl ether, and a combination of any of the above. An amino-functional vinyl ether may be 4-aminobutyl vinyl ether. A coreactive composition may comprise an epoxy-functional vinyl ether or a combination of epoxy-functional vinyl ethers. A hydroxyl-functional vinyl ether may have the structure of Formula (14): CH2=CH-O-(CH2)w-R (14) where w is an integer from 2 to 10, and R is an epoxy group. In the epoxy-functional vinyl ethers of Formula (14), w may be 2, 3, 4, 5, or w may be 6. An epoxy-functional vinyl ether may be 2-(4(vinyloxy¡)but¡l )oxrane. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ A coreactive composition may comprise, for example, from 0.1% by weight to 10% by weight of an amino-functional vinyl ether, from 0.2% by weight to 9% by weight, from 0.3% by weight to 0.7% by weight or from 0.4% by weight to 0.7% by weight, where the % by weight is a function of the total weight of the coreactive composition. A coreactive composition may comprise vinyl-based diluents such as styrene, α-methyl styrene, and para-vinyl toluene; vinyl acetate; and / or n-vinyl pyrrolidone as a reactive diluent. A coreactive composition may contain one plasticizer or a combination of plasticizers. Plasticizers may be included to adjust the initial viscosity of the coreactive composition and to facilitate application. Examples of suitable plasticizers include a combination of phthalates, terephalic, isophallic terphenyls, hydrogenated terphenyls, quaterphenyls and higher or polyphenyls, phthalate esters, chlorinated paraffins, modified polyphenyls, tung oil, benzoates, dibenzoates, thermoplastic polyurethane plasticizers, phthalate esters , naphthalene sulfonate trimellitates, adipates, sebacates, maleates, sulfonamides, organophosphates, polybutene, butyl acetate, butyl cellosolve, butyl carbitol acetate, dipentene, tributyl phosphate, hexadecanol, diallyl phthalate, sucrose acetate isobutyrate, iso-octyl tallate epoxy ester, benzophenone and combinations of any of the foregoing. A coreactive composition may comprise from 0.5% by weight to 7% by weight, of a plasticizer or a combination of plasticizers, from 1% by weight to 6% by weight, from 2% by weight to 5% by weight, or from 2% by weight to 4% by weight of a plasticizer or a combination of plasticizers, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition may comprise less than 8% by weight plasticizer, less than 6% by weight, less than 4% by weight or less than 2% by weight of a plasticizer or a combination of plasticizers, where the % by weight is in function of the total weight of the coreactive composition. A coreactive composition can comprise a corrosion inhibitor or a combination of corrosion inhibitors. Examples of suitable corrosion inhibitors include zinc phosphate based corrosion inhibitors, a lithium silicate corrosion inhibitor such as lithium orthosilicate (LkSiOi) and lithium metasilicate (LbSiOs), MgO, an azole, a monomeric amino acid , a dimeric amino acid, an oligomeric amino acid, a nitrogen-containing heterocyclic compound such as an azole, oxazole, tlazole, thiazolines, imidazole, diazole, pyridine, indolizine and triazine, tetrazole and / or tolyltriazole, corrosion-resistant particles such as particles of inorganic oxides, including, for example, zinc oxide (ZnO), magnesium oxide (MgO), cerium oxide (CeOz), molybdenum oxide (MoOs), and / or silicon dioxide (SiO?), and combinations of I 1 η / I 7Π7 / 3 / ΥΙΛΙ any of the above. A coreactive composition may comprise less than 5% by weight of a corrosion inhibitor or a combination of corrosion inhibitors, less than 3% by weight, less than 2% by weight, less than 1% by weight or less than 0.5% by weight. weight of a corrosion inhibitor or a combination of corrosion inhibitors, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition may comprise, for example, more than 0.1% by weight of a corrosion inhibitor, more than 0.5% by weight, more than 1% by weight or more than 2% by weight of a corrosion inhibitor, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition may comprise a flame retardant or a combination of flame retardants. A flame retardant can include an inorganic flame retardant, an organic flame retardant, or a combination of these. Examples of suitable inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, zinc borate, antimony oxides, hydromagnesite, aluminum trihydroxide (ATH), calcium phosphate, titanium oxide, zinc oxide, magnesium carbonate, barium, barium borate, kaolinite, silica, antimony oxides, and combinations of any of the foregoing. Examples of suitable organic flame retardants include halocarbons, halogenated esters, halogenated ethers, chlorinated and / or brominated flame retardants, halogen-free compounds such as organophosphorus compounds, organonitrogen compounds, and combinations of any of the foregoing. A coreactive composition may comprise, for example, from 1% by weight to 30% by weight, such as from 1% by weight to 20% by weight, or from 1% by weight to 10% by weight of a flame retardant or a combination of flame retardants based on the total weight of the coreactive composition. For example, a coreactive composition may comprise less than 30% by weight, less than 20% by weight, less than 10% by weight, less than 5% by weight or less than 2% by weight of a flame retardant or combination of flame retardants. based on the total weight of the coreactive composition. A coreactive composition can comprise a moisture control additive or a combination of moisture control additives. Examples of suitable moisture control additives include synthetic zeolite, activated alumina, silica gel, calcium oxide, magnesium oxide, molecular sieve, anhydrous sodium sulfate, anhydrous magnesium sulfate, alkoxysilanes, and combinations of any of the foregoing. I br1 n / I 7Π7 / 3 / ΥΙΛΙ A coreactive composition may comprise less than 5% by weight of a moisture control additive or a combination of moisture control additives, less than 3% by weight, less than 2% by weight, less than 1% by weight or less. of 0.5% by weight of a moisture control additive or a combination of moisture control additives, where the % by weight is based on the total weight of the coreactive composition. A coreactive composition can comprise a UV stabilizer or a combination of UV stabilizers. UV stabilizers include UV absorbers and hindered amine light stabilizers. Examples of UV stabilizers include products under the trade names Cyasorb® (Solvay), Uvinul® (BASF) and Tinuvin® (BASF). A coreactive composition can include colorants such as pigments and / or dyes. Examples of suitable inorganic pigments include metal-containing inorganic pigments, such as those containing cadmium, carbon, chromium, cobalt, copper, iron oxide, lead, mercury, titanium, tungsten, and zinc. Other examples are ultramarine blue, ultramarine violet, reduced tungsten oxide, cobalt aluminate, cobalt phosphate, manganese pyrophosphate, and metal-free inorganic pigments. An inorganic pigment nanoparticle can comprise ultramarine blue, ultramarine violet, Prussian blue, cobalt blue, and / or reduced tungsten oxide. Some examples of specific organic pigments are indanthrone, quinacridone, phthalocyanine blue, copper phthalocyanine blue, and perylene anthraquinone. Other examples of suitable pigments are iron oxide pigments, in all shades of yellow, brown, red and black; in all its physical forms and grain categories; titanium oxide pigments in all the different inorganic surface treatments; chromium oxide pigments also coprecipitated with nickel and nickel titanates; black pigments from organic combustion (eg carbon black); blue and green pigments derived from copper phthalocyanine, also chlorinated and brominated, in the different crystalline forms α, β and ε; yellow pigments derived from lead sulfochromate; yellow pigments derived from lead bismuth vanadate; orange pigments derived from lead sulfochromate molybdate; yellow pigments of an organic nature based on arylamides; orange pigments of an organic nature based on naphthol; orange pigments of an organic nature based on diketo-pyrrolo-pyrrole; red pigments based on manganese salts of azo dyes; red pigments based on manganese salts of beta-oxynaphthoic acid; organic quinacridone red pigments; and organic anthraquinone red pigments. Examples of suitable dyes include acridines, anthraquinones, arylmethane dyes, azo dyes, phthalocyanine dyes, quinone imine dyes, including those I 1 n / L7n7 / q / YIAI azine dyes, indamines, indophenyls, oxazines, oxazones and thiazines, tlazol dyes, safranin dyes, xanthene dyes, including fluorene dyes. Examples of suitable dyes are Alcian Blue, Alcian Yellow, Alizarin, Alizarin Red, Alizarin Yellow, Azofloxin, Bismarck Brown R, Bismarck Brown Y, Cresyl Brilliant Blue, Chrysoidin R, Chrysoidin Y, Congo Red, Crystal Violet, Ethyl Green, Acid Fuchsin , Gentian Violet, Janus Green, Lissamine Yellow, Malachite Green, Mars Yellow, Meldola Yellow, Methanyl Yellow, Methyl Orange, Methyl Red, Naphthalene Black, Naphthol Green, Naphthol Yellow, G Orange , glitter, rose bengal, Sudan II, Titan yellow, tropaeolin O, tropaeolin 00, tropaeolin 000, Victoria blue and xylene cyanol. A coreactive composition can comprise a photochromic material or a combination of photochromic materials. A photochromic material can be a reversible photochromic material or a non-reversible photochromic material. A photochromic material can be a thermally reversible photochromic material or a thermally non-reversible photochromic material. A photochromic material can be a compound that is activated by absorbing actinic radiation of a certain wavelength, such as UV radiation, which causes a change in a characteristic of the photochromic material. A characteristic change is an identifiable change in a characteristic of the photochromic material that can be detected through the use of an instrument or visually. Examples of feature changes include a change in color or color intensity and a change in structure or other interactions with energy in the visible UV, infrared (IR), near IR, or far IR portions of the electromagnetic spectrum, such as absorption. and / or reflectance. A color change at visible wavelengths refers to a color change at wavelengths within the range of 400 nm to 800 nm. A photochromic material can be activated by absorbing radiation energy (visible and non-visible light) with a particular wavelength, such as UV light, to undergo a characteristic change, such as a color change. The characteristic change may be a characteristic change of the photochromic material alone or it may be a characteristic change of a coreactive composition. Examples of suitable photochromic materials include spiropyrans, spiropyrimidines, spiroxazines, diareletenes, photochromic quinones, azobenzenes, other photochromic dyes, and combinations of these. These photochromic materials may undergo a reversible or irreversible change in characteristic when exposed to radiation, where the first and second states may be different colors or different intensities of the same color. A coreactive composition may comprise a photochromic agent sensitive to the degree of cure or the degree of exposure to actinic radiation. A cure indicator can I 1 Π / I 7Π7 / 3 / ΥΙΛΙ change color when exposed to actinic radiation, which may be permanent or reversible. A cure indicator may be initially transparent and turn colored upon exposure to actinic radiation, or it may be initially colored and become transparent upon exposure to actinic radiation. A layer of a multilayer system provided by the present disclosure that exhibits low temperature flexibility may comprise, for example, prepolymers such as silicones, polytetrafluoroethylenes, polyethers, polysulfides, polyformals, polybutadienes, certain elastomers, and combinations of any of the foregoing. A layer of a multilayer system provided by the present disclosure that exhibits hydrolytic stability may comprise, for example, prepolymers such as silicones, polytetrafluoroethylenes, polyethers, polysulfides, polyformals, polybutadienes, certain elastomers, and combinations of any of the foregoing, or compositions having a high crosslinking density and / or may comprise an elastomer. A layer of a multilayer system provided by the present disclosure that exhibits resistance to high temperatures may comprise, for example, prepolymers such as silicones, polytetrafluoroethylenes, polyethers, polysulfides, polyformals, polybutadienes, certain elastomers, and combinations of any of the foregoing; or compositions having a high density of crosslinking. A layer of a multilayer system provided by the present disclosure that exhibits high tensile strength may comprise, for example, elastomeric prepolymers such as silicones and polybutadiene, compositions having high crosslinking density, inorganic filler, and combinations of any of the previous ones. A layer of a multilayer system provided by the present disclosure that exhibits a high % elongation may comprise, for example, elastomeric prepolymers such as silicones and polybutadiene, compositions having a high crosslink density, inorganic filler, and combinations of any of the previous ones. A layer of a multilayer system provided by the present disclosure that exhibits adhesion to substrate or adhesion to a primer coating may comprise, for example, adhesion promoters such as organofunctional alkoxysilanes, phenolic resins, baked phenolic resins, and combinations of any of the foregoing. , titanates, partially hydrolyzed alkoxysilanes or combinations thereof. A layer of a multilayer system provided by the present disclosure that exhibits interlayer adhesion may comprise, for example, adhesion promoters, unreacted functional groups that are reactive with compounds in the adjacent layer, and combinations thereof. I br1 n / I 7Π7 / 3 / ΥΙΛΙ A layer of a multilayer system provided by the present disclosure that exhibits fast tack-free time can comprise, for example, co-reactants having fast curing chemistry, actinic radiation curable systems, catalysts, and combinations of any of the foregoing. A layer of a multi-layer system provided by the present disclosure may exhibit, for example, a tack-free time of less than 5 minutes, where the tack-free time is from when the co-reactants are first mixed to the time a ball cotton no longer adheres to the surface of the curing sealant. A layer of a multilayer system provided by the present disclosure that exhibits a fast time to a Shore 10A hardness can comprise, for example, co-reactants having fast-curing chemistry, actinic radiation-curable systems, catalysts, and combinations of any of the following. previous. A layer of a multilayer system provided by the present disclosure that exhibits electrical conductivity, EMI / RFI shielding, and / or static dissipation may comprise, for example, an electrically conductive filler or a combination of electrically conductive fillers. A layer of a multilayer system provided by the present disclosure that exhibits a low density may comprise, for example, a low density filler, such as a low density organic filler, hollow microspheres, coated microspheres, or combinations of any of the above. A layer of a multilayer system provided by the present disclosure that exhibits corrosion resistance may comprise, for example, one or more corrosion inhibitors. A layer of a multilayer system provided by the present disclosure that exhibits corrosion resistance may comprise, for example, one or more inorganic fillers. When cured, a multilayer system provided by the present disclosure may exhibit, for example, one or more of the following characteristics: desired solvent resistance, low temperature flexibility, hydrolytic stability, high temperature resistance, high tensile / elongation, adhesion to substrate, adhesion to a primer coating, adhesion to an adjacent coat, fast tack-free time, fast time to Shore 10A hardness, electrical conductivity, EMI / RFI shielding, static dissipation, corrosion resistance, sound deadening, or a combination of any of the above. For example, after exposure to jetting reference fluid (JRF Type 1) in accordance with ISO 1817 for 168 hours at 60°C, a cured multilayer provided by the I 1 Π / I 7Π7 / 3 / ΥΙΛΙ system of the present disclosure can exhibit a tensile strength greater than 1.4 MPa determined in accordance with ISO 37, a tensile elongation greater than 150% determined in accordance with ISO 37 and a Hardness greater than Shore 30A determined in accordance with ISO 868, where tests were carried out at a temperature of 23°C and a humidity of 55% RH. Upon exposure to a de-icing fluid in accordance with ISO 11075 Type 1 for 168 hours at 60°C, a cured multilayer system provided by the present disclosure may exhibit a tensile strength greater than 1 MPa as determined in accordance with ISO 37 and a tensile elongation greater than 150% determined in accordance with ISO 37, where the tests were carried out at a temperature of 23°C and a humidity of 55% RH. A chemically resistant multilayer system provided by the present disclosure may exhibit a % swell of less than 25%, less than 20%, less than 15%, or less than 10% after immersion in a chemical for 7 days at 70°C, where the % swelling is determined according to EN ISO 10563. A multilayer system provided by the present disclosure that exhibits low % swell may comprise, for example, high crosslink density. The % swell can be determined by immersing a cured composition in a particular solvent for 7 days at 70°C in accordance with EN ISO 10563. A multilayer system provided by the present disclosure may exhibit, for example, a tensile strength as cure of at least 1 MPa according to ISO 37 at 23°C / 55% RH. A multilayer system provided by the present disclosure may exhibit, for example, a % elongation as cure of at least 150% determined in accordance with ISO 37 at 23°C / 55% RH. A multi-layer system provided by the present disclosure can exhibit a rapid time to Shore 10A hardness of less than 10 minutes, where hardness is determined in accordance with ISO 868 at 23°C / 55% RH. An electrically conductive multilayer system or a layer of a multilayer system provided by the present disclosure may exhibit a surface resistivity, for example, less than 10sOhm / sq, less than 105Ohms / sq, less than 104Ohms / sq, less than 103Ohms / sq. , less than 102Ohm / square, less than 10 Ohm / square, less than 10'1Ohm / square, or less than 10'2Ohm / square. An electrically conductive multilayer system surface or layer of a multilayer system provided by the present disclosure may have a surface resistivity of, for example, 10'2 to 102, 102 Ohm / sq to 106 Ohm / sq, or 103 Ohm / sq. at 105Ohm / sq. Surface resistivity can be determined in accordance with ASTM D257 at 23°C / 55% RH. I br1 n / I 7Π7 / 3 / ΥΙΛΙ A multilayer system or one layer of a cap of a multilayer system provided by the present disclosure may have a volume resistivity, for example, less than 106 Ohm / cm, less than 105 Ohm / cm, less than 104 Ohm / cm, less than 103 Ohm / cm, less than 102Ohm / cm, less than 10 Ohm / cm, less than 10'1Ohm / cm or less than 10'2Ohm / cm. An electrically conductive multilayer system or a layer of a multilayer system may have a volume resistivity of, for example, 10.2Ohm / cm to 101Ohm / cm, 102Ohm / cm to 106Ohm / cm, or 103Ohm / cm to 105Ohm / cm. Volume resistivity can be determined in accordance with ASTM D257 at 23°C / 55% RH. A multilayer system or a layer of a cap of a multilayer system provided by the present disclosure may have an electrical conductivity of, for example, greater than 1 S cm-1, greater than 10 S cm-1, greater than 100 S cm-1 , greater than 1,000 S cm-1 or greater than 10,000 S cm-1. An electrically conductive multilayer system can have an electrical conductivity of 1 S cm-1 at 10,000 S cm-1, 10 S cm-1 at 1,000 cm-1, or 10 S cm-1 at 500 S cm-1. Electrical conductivity can be determined in accordance with ASTM D257 at 23°C / 55% RH. A multilayer system or a layer of a multilayer system provided by the present disclosure may exhibit attenuation at frequencies within the range of 10 KHz to 20 GHz, for example, greater than 10 dB, greater than 30 dB, greater than 60 dB, greater than 90 dB or greater than 120 dB. An electrically conductive multilayer system provided by the present disclosure may exhibit attenuation at frequencies within the range of 10 KHz to 20 GHz, for example, 10 dB to 120 dB, 20 dB to 100 dB, 30 dB to 90 dB or from 40 dB to 70 dB. Shielding effectiveness can be determined in accordance with ASTM D4935 at 23°C / 55% RH. A multilayer system or a layer of a multilayer system provided by the present disclosure exhibits a thermal conductivity of 0.1 to 50 W / (m-K), 0.5 to 30 W / (m-K), 1 to 30 W / (m-K), of 1 to 20 W / (m-K), 1 to 10 W / (m-K), 1 to 5 W / (m-K), 2 to 25 W / (m-K), or 5 to 25 W / (m-K). Thermal conductivity can be determined in accordance with ASTM D1461 at 23°C / 55% RH. A multilayer system or a layer of a multilayer system provided by the present disclosure may exhibit a specific gravity, for example, less than 1.1, less than 1.0, less than 0.9, less than 0.8, or less than 0.7, where the specific gravity is determined in accordance with ISO 2781 at 23°C / 55% RH. A multilayer system or a layer of a multilayer system provided by the present disclosure may exhibit a hardness of, for example, greater than Shore 20A, greater than Shore 30A, greater than Shore 40A, greater than Shore 50A, or greater than Shore 60A, where the Hardness is determined according to ISO 868 at 23°C / 55% RH. A cured multi-coat system may have acceptable properties for use in a I br1 n / I 7Π7 / 3 / ΥΙΛΙ vehicle and aerospace sealing applications. In general, it is desirable for sealants used in aircraft and aerospace applications to exhibit the following properties: Peel strength greater than 20 pounds per linear inch (pli) on AMS 3265B substrates determined under dry conditions, after immersion in Type I JRF for 7 days, followed by immersion in 3% NaCI aqueous solution per AMS 3265B test specifications; tensile strength between 300 pounds per square inch (psi) and 400 psi (2.75 MPa); Tear strength greater than 50 pounds per linear inch (pli) (8.75 N / mm); elongation between 250% and 300%; and hardness greater than 40 durometer A. These and other appropriate properties for aircraft and aerospace applications are listed in AMS 3265B. It is also desirable that, once cured, the multilayer systems of the present disclosure used in aviation and aeronautical applications exhibit a volume swelling percentage of no more than 25% after immersion for one week at 60°C and ambient pressure in the Jet Reference Fluid (JRF) Type I. Other properties, ranges, and / or thresholds may be appropriate for other sealing applications. A multilayer system provided by the present disclosure can be fuel resistant. The term "fuel resistant" can mean that a composition, when applied to a substrate and cured, can provide a cured product, such as a sealant, having a percent swell by volume of not more than 40%, in some cases not more than at 25%, in some cases not more than 20%, and in other cases not more than 10%, after immersion for one week at 60°C and ambient pressure in Type I JRF according to methods similar to those described in ASTM D792 (American Society for Testing and Materials) or AMS 3269 (Aerospace Materials Specification). Type I JRF, as used for determination of fuel resistance, has the following composition: toluene: 28 ± 1% by volume; Cyclohexane (technical): 34 ± 1% by volume; isooctane: 38 ± 1% by volume; and tertiary dibutyl disulfide: 1 ± 0.005% by volume (see AMS 2629, published Jul 1, 1989 § 3.1.1, etc., available from SAE (Society of Automotive Engineers)). A chemically resistant multilayer system provided by the present disclosure can exhibit a tensile elongation of at least 200% and a tensile strength of at least 200 psi when measured in accordance with the procedure described in AMS 3279, § 3.3.17.1. , test procedure AS5127 / 1, § 7.7. A multilayer system provided by this disclosure may exhibit a coating shear strength greater than 200 psi (1.38 MPa), such as at least 220 psi (1.52 MPa), at least 250 psi (1.72 MPa), and in some cases, at least 400 psi (2.76 MPa), when measured according to the procedure described in paragraph 7.8 of SAE AS5127 / 1. I br1 n / I 7Π7 / 3 / ΥΙΛΙ A multi-layer system provided by this disclosure can meet or exceed the requirements for aerospace sealants set forth in AMS 3277. A layer of a multilayer system provided by the present disclosure that imparts sound deadening properties may comprise an epoxy-containing compound, wherein the epoxy-containing compound comprises an epoxy / polyol adduct, a polytol, and a curing agent. A multilayer system provided by the present disclosure can impart sound damping properties to a structure. For example, when a multilayer system with sound deadening properties is applied to a substrate, the substrate may have a sound deadening loss factor of at least 0.06 at 800 Hz, at least 0.04 at 400 Hz, or at least 0.02 at 200 Hz at 10°C, with a 2.5 mm sealant thickness as measured per SAE J1637 and ASTM E756 test method on 240 mm long, 10 mm wide, 1 mm thick steel panels coated along 215 mm of length. A multilayer system can comprise one or more coatings. A coating may be provided on the outer surface of the inner layer of the multilayer system, on the outer surface of the outer layer of the multilayer system, and / or between one or more layers of the multilayer system. A coating refers to a layer that is less thick than a layer of the multilayer system. A multi-layer system provided by the present disclosure may comprise an intermediate coating between the layers, an inner coating, an outer coating, or a combination of any of the above. An intermediate coating refers to a coating between contiguous layers; an interior coating refers to a coating that is adjacent to a surface; and an outer coating is on the outer surface of the multilayer system. Examples of coatings are shown in Figure 3. Figure 3 shows a cross-sectional view of a multilayer system having a first layer 302 on a substrate 305, and a second layer 301 on the first layer 302. A first coating 304 is disposed between the first layer 302 and the substrate 305. to improve, for example, adhesion and / or corrosion resistance. A second coating 303 is arranged between the first and second layers 301 / 302 to improve, for example, interlayer adhesion. A third coating 306 may coat the outer surface of the multilayer system and may be configured to improve, for example, the chemical resistance, abrasion resistance, or electrical conductivity of one or more layers of a multilayer system. An inner or outer intermediate coating may have a thickness, for example, from 0.001 to 2 mm, from 0.01 mm to 1 mm, from 0.05 mm to 0.5 mm, or from 0.1 mm to 0.4 mm. A coating may have a thickness, for example, less than 2 mm, less than 1 mm, less than I br / n / I 7Π7 / 3 / ΥΙΛΙ 0.5mm, less than 0.1mm or less than 0.05mm. The thickness of the coating can be less than that of the layers that make up the multilayer system. An intermediate coating can be used to improve or provide certain desired properties to the multilayer system, such as interlayer adhesion, electrical conductivity, EMI / RFI shielding, or a combination of any of the above. An intermediate coating may comprise compounds comprising functional groups reactive with the reactive compounds of the underlying and / or superimposed layers. For example, where the overlying and / or underlying layers comprise coreactive compounds having thiol-functional groups, an intermediate coating layer may comprise compounds having groups reactive with thiol groups, such as alkenyl groups, alkynyl groups, isocyanate groups, thiol groups, or epoxy groups. An interior coating can provide adhesion to a substrate, provide corrosion resistance, or a combination of both. For example, an inner coating may comprise, for example, adhesion promoters, corrosion inhibitors, partially hydrolyzed / condensed Organo-functional alkoxysilanes, and combinations of any of the foregoing. An overlay can be configured to provide aesthetics, static dissipation, electrical conductivity, EMI / RFI shielding, or a combination of any of the above. For example, an outer coating may comprise, for example, a colorant, electrically conductive filler, or a combination of these. A multi-coat system may include an outer coating such as a clear coat, abrasion resistant coating, colored coating, textured coating, solvent resistant coating, UV protective coating, haptic capability, or a combination of any. of the above, superimposed on the multilayer system. Surface coatings can be used to impart a desired surface property such as, for example, electrical conductivity, reflectivity such as IR reflectivity, color, wavelength dependent absorption, wavelength dependent reflectivity, scratch resistance , abrasion resistance, smudge resistance, fingerprint resistance, cleaning fluid resistance, imparting aesthetic attributes, and / or imparting tactile properties. The coating may comprise a multilayer coating. A coating may be a haptic coating such as a soft touch coating. The coating may be applied to an extrudate by an extrusion coating die. The multilayer system provided by the present disclosure may be prepared by depositing an extrudate comprising a coreactivating sealer composition or a coextrudate comprising a coreactivating sealer composition and one or more additional compositions onto a I 1 n / I 7Π7 / 3 / ΥΙΛΙ substrate. A multi-layer system can be applied by additive manufacturing methods. Additive manufacturing is widely used to encompass robotic manufacturing methods. Additive processing includes, for example, three-dimensional printing, extrusion and co-extrusion. Using additive manufacturing methods, a multilayer system comprising individual layers of a coreactive composition can be applied directly onto a substrate and then cured and / or allowed to cure to provide a cured multilayer system. A multilayer system can be applied by coextrusion. Coextrusion is widely used to refer to methods in which a multilayer system is applied to a substrate by pressure. Pressure can be applied manually or automatically. Coextrusion includes processes that include extrusion through a coextrusion die or combining parallel flows of coreactive compositions. Co-extrusion facilitates the ability of a multi-layer system to be applied to a substrate in a single process. By simultaneously applying the layers of a multilayer system, the ability to maintain the consistency, reproducibility, and integrity of the multilayer system can be facilitated. A first and a second coreactive composition may be coextruded through a coextrusion die that is of a suitable shape to provide a coextrudate. A schematic of an example of a coextruder is shown in Figure 4. The coextruder includes a barrel 401, a first inlet 402 for a first coreactive composition 403, a second inlet 404 for a second coreactive composition 405, and an outlet nozzle 406. The inlets can be coupled to pumps that control the flow of the coreactive compositions into the coextruder. The co-extruder barrel may comprise sensors coupled to the pumps to control the flow of coreactive compositions into the extruder barrel. The flow of the coreactive compositions can be controlled such that the flows merge but do not mix. In the outlet die 406 the coreactive compositions 408 can be molded to provide a coextrudate 409. As shown in Figure 4 the coextrudate is in the form of a sheet in which the first coreactive composition 403 is overlaid with the second coreactive composition. 405. The coextrudate can be applied to a part or to the surface to be sealed. A co-extruder may comprise pressure controls, extrusion flasks, co-extrusion flasks, coaters, temperature control elements, elements for irradiating a coreactivating sealant composition, or combinations of any of the foregoing. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ For automated manufacturing, the co-extruder can be mounted on apparatus for moving a die relative to a surface. The automated manufacturing apparatus including the co-extruder may be controlled by a processor. Coextrusion methods are versatile enough that a wide range of coextrusion structures can be manufactured. For example, for a three-dimensional multilayer system, the coextrusion may have a core-shell configuration comprising an inner layer comprising a first composition and an outer layer comprising a second composition. The core-shell coextrusion can be applied directly onto a three-dimensional surface as a single unit. For a two-dimensional multi-layer system, the coextrusion may be in the form of a sheet having two or more superimposed layers. A surface can be sealed by applying successive sheets of the multilayer system adjacent to a previously deposited sheet of the multilayer system. A multi-coat system can be manufactured as a separate component that can be subsequently applied to the surface to be sealed. For example, a multilayer system can be manufactured as a sheet or a preform that has a desired shape and is fully or partially cured. The partially or fully cured multi-coat system component can then be applied to a surface. A multi-coat system can be applied directly to a surface to be sealed. For example, the individual layers of a multi-layer system can be applied sequentially to a surface where one or more of the layers are applied by the coreactive three-dimensional printing methods provided by the present disclosure. A multilayer system provided by the present disclosure can be coextruded directly onto the surface to be sealed. As a consequence of having multiple layers, these can be interfaces between each of the layers of the multilayer system. The integrity of the layer interfaces can be maintained in view of the requirement of the overall performance of the multilayer system. Interlayer adhesion between adjoining layers of a multilayer system can be improved in a number of ways. For example, an adhesion promoting coating can be applied between adjacent layers. An adhesion promoting coating can include adhesion promoters and / or reactive groups that can be non-covalently attached or covalently attached to one or more of the constituents of adjacent layers. Adhesion between adjoining strips of a multilayer system can be improved by facilitating the ability of adjoining layers to bond chemically and / or physically. This can be achieved, for example, by including coreactive compositions in the contiguous bands of the system. I ΗΓ1 n / L7n7 / q / YIAI multilayer having reactive compounds that can chemically react with compounds of a contiguous coreactive composition. For example, in the case of layers based on thiol-ene chemistry, an adhesion promoting interlayer may include compounds having non-reactive groups capable of reacting with the thiol and / or alkenyl groups of the overlying and underlying layers. . The rate of crosslinking between adjacent layers in a multilayer system can be controlled to facilitate interlayer reaction and thus improve layer strength. For example, it may be desirable for adjacent layers to be chemically bonded together. To achieve this, a second layer can be deposited on top of a first layer before the first layer is fully cured, so that the first layer has unreacted functional groups capable of reacting with the functional groups of the second layer. The rate of crosslinking between layers can be controlled, for example, by adjusting the time between deposition of successive layers, adjusting the temperature, adjusting the concentration of a catalyst, and / or adjusting the components of the composition, such as the amount of monomer and prepolymer. A layer can be homogeneous, or a layer can be inhomogeneous. In the case of an inhomogeneous layer, a cross section of the layer may have different chemical compositions along the profile. For example, to improve interlayer adhesion, a part of one layer may have an excess of a certain coreactive functionality that can react with an excess of a coreactive functionality of an overlying layer. Similarly, to improve interlayer adhesion, a lower portion of a layer can have an excess of a given coreactive functionality that can react with an excess of a coreactive functionality of an underlying layer. To improve interlayer bonding and / or adhesion, a bond coat, film or other treatment may be applied or deposited onto a deposited layer before or during the deposition of an overlay. The tie layer between layers can include, for example, compounds reactive with adjacent layers, catalysts, and / or adhesion promoters. An interleaf tie layer can be applied to a surface of the extrudate by co-extrusion. A layer can be applied to at least a part of the surface of a coreactive and / or coextruded composition. A coating can be applied, for example, by passing a coextrudate through a liquid composition to provide a coating on the outer surface or a part of the outer surface of the coextrudate. The coating may comprise materials that improve adhesion between adjacent strips of the multilayer system. For example, a thin film coating may comprise compounds having groups reactive with functional groups of the coreactive compositions that make up the multilayer system. Coextruded multilayer systems can also be configured to facilitate I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ adhesion to multiple substrates. For example, an adhesion package can be optimized to bond the inner layer of a multilayer system to a particular substrate. However, the adhesion package may not be optimal to facilitate adhesion to a different substrate. For example, different bonding packages can be optimized for bonding to different metals such as aluminum and titanium, or to composites and metals. An innermost layer of a multilayer system can include two or more portions having different adhesion packages, and the other components of the coreactive composition that make up the inner layer can be substantially the same or different. In this way, the adhesion of a multilayer system to a substrate composed of different materials can be improved. An extrudate or coextrudate can be deposited in any orientation. For example, the nozzle can be directed downwards, upwards, to the sides, or at any angle in between. In this way, a multilayer system can be deposited as a vertical wall or as a cantilever. An extrudate or coextrudate can be deposited on a vertical wall, on the bottom surface of a sloped wall, or on the bottom of a horizontal surface. The use of an extrudate or coextrudate with a fast curing chemistry can facilitate the ability of an overlying layer to be deposited adjacent to an underlying layer such that an angled surface can be produced. The angled surface can be sloped up from the horizontal or down from the horizontal. A coreactive composition can have a volumetric flow rate, for example, from 0.1 mL / min to 20,000 mL / min, such as from 1 mL / min to 12,000 mL / min, from 5 mL / min to 8,000 mL / min, or from 10 mL / min to 6,000 mL / min. The volumetric flow rate may depend, for example, on the viscosity of a coreactive composition, the extrusion pressure, the diameter of the die, and the reaction rate of the coreactive compounds. A coreactive composition can be used at a printing speed, for example, from 1 mm / s to 400 mm / s, such as 5 mm / s to 300 mm / s, 10 mm / s to 200 mm / s, or 15 mm / s. s at 150mm / s. The printing speed may depend, for example, on the viscosity of the coreactive composition, the extrusion pressure, the diameter of the nozzle and the reaction rate of the coreactive components. Print speed refers to the speed at which a nozzle used to extrude a coreactive composition moves relative to a surface on which the coreactive composition is deposited. A multi-layer system comprising a sealant layer provided by the present disclosure can be used in any application where a sealant is used to protect a surface from an environment of use. A multilayer can be used, for example, to seal parts and surfaces of motor vehicles and aerospace. A multi-coat system can be applied directly or deposited on the surface I br1 n / I 7Π7 / 3 / ΥΙΛΙ from a substrate or over a coating, such as a primer coating or an adhesion promoting coating. A multilayer system provided by the present disclosure can be applied to or deposited on any of a variety of substrates. Examples of substrates to which a multi-layer system can be applied include metals such as titanium, stainless steel, alnico, aluminum and aluminum alloy, any of which can be anodized, primed, coated organic or chrome; or may include epoxy, urethane, graphite, fiberglass composite, Kevlar®, acrylics, polycarbonates, and combinations of any of the foregoing. A cured multilayer system provided by the present disclosure may exhibit acceptable properties for use in vehicle applications, such as automotive and aerospace sealing applications. In general, it is desirable for sealants used in aircraft and aerospace applications to exhibit the following properties: Peel strength greater than 20 pounds per linear inch (pli) on AMS 3265B substrates determined under dry conditions, after immersion in Type I JRF for 7 days, followed by immersion in 3% NaCI solution per AMS 3265B test specifications; tensile strength between 300 pounds per square inch (psi) and 400 psi (2.75 MPa); Tear strength greater than 50 pounds per linear inch (pli) (8.75 N / mm); elongation between 250% and 300%; and hardness greater than 40 durometer A. These and other appropriate cured properties of a multilayer system for aircraft and aerospace applications are listed in AMS 3265B. It is also desirable that, once cured, a multilayer system of the present disclosure used in aviation and aeronautical applications present a volume swelling percentage of no more than 25% after immersion for one week at 60°C and ambient pressure in the Jet Reference Fluid (JRF) Type 1. Other properties, ranges, and / or thresholds may be appropriate for other sealing applications, such as automotive. The multilayer system provided by the present disclosure can exhibit a tensile elongation of at least 200% and a tensile strength of at least 200 psi when measured in accordance with the procedure described in AMS 3279, § 3.3.17.1, Procedure test AS5127 / 1, § 7.7. A multilayer system provided by this disclosure may exhibit a coating shear strength greater than 200 psi (1.38 MPa), such as at least 220 psi (1.52 MPa), at least 250 psi (1.72 MPa), and in some cases, at least 400 psi (2.76 MPa), when measured according to the procedure described in paragraph 7.8 of SAE AS5127 / 1. I br1 n / I 7Π7 / 3 / ΥΙΛΙ A multi-layer system prepared using the methods provided by this disclosure can meet or exceed the requirements for aerospace sealants set forth in AMS 3277. Prior to environmental exposure, a multilayer system provided by the present disclosure exhibits a density less than 1.2 g / cm3 (specific gravity less than 1.2) determined in accordance with ISO 2781, a tensile strength greater than 1 MPa determined in accordance with ISO 37, a tensile elongation greater than 150% determined in accordance with ISO 37 and a hardness greater than Shore 40A determined in accordance with ISO 868, where the tests were carried out at a temperature within a range of 21°C at 25°C and a humidity of 45% RH to 55% RH. After exposure to aviation fuel fluid (JRF Type 1) in accordance with ISO 1817 for 168 hours at 60°C, a multilayer system may exhibit a tensile strength greater than 1.4 MPa determined in accordance with ISO 37, a tensile elongation greater than 150% determined in accordance with ISO 37 and a hardness greater than Shore 30A determined in accordance with ISO 868, where the tests were carried out at a temperature within the range of 21°C to 25°C and a humidity of 45% RH to 55% RH. Upon exposure to 3% aqueous NaCI fluid for 168 hours at 60°C, a multilayer system may exhibit a tensile strength greater than 1.4 MPa determined in accordance with ISO 37, a tensile elongation greater than 150% determined in accordance with ISO 37 and a hardness greater than Shore 30A determined in accordance with ISO 868, where the tests were carried out at a temperature within the range of 21°C to 25°C and a humidity of 45% RH at 55% HR. Upon exposure to a de-icing fluid in accordance with ISO 11075 Type 1 for 168 hours at 60°C, a multilayer system provided by the present disclosure can exhibit a tensile strength greater than 1 MPa determined in accordance with ISO 37 and a tensile elongation greater than 150% determined in accordance with ISO 37, where tests were carried out at a temperature within the range of 21°C to 25°C and a humidity of 45% RH to 55% RH . Upon exposure to a phosphate ester hydraulic fluid (Skydrol® LD-4) for 1,000 hours at 70°C, a multilayer system provided by the present disclosure may exhibit a tensile strength greater than 1 MPa as determined in accordance with ISO 37, a tensile elongation greater than 150% determined in accordance with ISO 37 and a hardness greater than Shore 30A determined in accordance with ISO 868, where the tests were carried out at a temperature within the range of 21°C to 25°C and a humidity of 45% RH to 55% RH. A multilayer system provided by the present disclosure may have a I br1 n / I 7Π7 / 3 / ΥΙΛΙ glass transition temperature, for example, less than -10°C, less than -20°C, less than 30°C, less than -40°C, less than -50 °C or less than -60 °C. The multilayer system manufacturing methods and multilayer systems manufactured by the methods can be used to seal any suitable part, such as a vehicle part or surface. The term vehicle is used in its broadest sense and includes all types of aerospace vehicles, watercraft, and ground vehicles. For example, a vehicle may include aerospace vehicles, such as airplanes, including private aircraft, and small, medium, or large aircraft for commercial passenger, cargo, and military use; helicopters, including private, commercial and military helicopters; rockets and spaceships. A vehicle can include a land vehicle such as, for example, automobiles, trailers, trucks, buses, vans, construction vehicles, golf carts, motorcycles, bicycles, trains, and railroad cars. A vehicle can also include vessels such as ships, boats, and hovercraft. A multilayer system can be used on an F / A-18 aircraft or related aircraft such as the F / A-18E Super Hornet and F / A-18F; on the Boeing 787 Dreamliner, 737, 747, 717 and related aircraft (produced by Boeing Commercial Airplanes); in the V-22 Osprey; VH-92, S-92, and related aircraft (produced by NAVAIR and Sikorsky); on the G650, G600, G550, G500, G450, and related aircraft (produced by Gulfstream); and on the A350, A320, A330, and related aircraft (produced by Airbus). A multilayer system can be used on commercial, military, or general aviation aircraft, such as, for example, those manufactured by Bombardier Inc. and / or Bombardier Aerospace, such as Canadair Regional Jet (CRJ) and related aircraft; made by Lockheed Martin, such as the F-22 Raptor, F-35 Lightning, and related aircraft; manufactured by Northrop Grumman such as the B-2 Spirit and related aircraft; manufactured by Pilatus Aircraft Ltd.; Manufactured by Eclipse Aviation Corporation; or manufactured by Eclipse Aerospace (Kestrel Aircraft). The multi-layer systems provided by the present disclosure can be used to seal vehicle parts and surfaces, such as fuel tank surfaces and other surfaces exposed or potentially exposed to solvents, hydraulic fluids, lubricants, oils and fuels. The present invention includes parts sealed with a multilayer system provided by the present disclosure, and assemblies and apparatus comprising a part sealed with a multilayer system provided by the present disclosure. Openings, surfaces, joints, fillets, fay surfaces, including openings, surfaces, fillets, joints and fay surfaces of vehicles, sealed with the multi-layer system, are I br1 n / I 7Π7 / 3 / ΥΙΛΙ included in the scope of the invention. Parts, such as vehicle parts, including automotive vehicle parts and aerospace vehicle parts, sealed by the methods provided by the present disclosure are included within the scope of the invention. The present invention includes vehicles comprising a part such as a surface sealed with a multilayer system provided by the present disclosure. For example, an aircraft comprising a fuel tank or a portion of a fuel tank sealed with a multilayer system is included in the scope of the invention. Vehicles, such as sealed automotive vehicles and aerospace vehicles comprising parts sealed using the methods provided by the present disclosure, are included within the scope of the invention. A multilayer system provided by the present disclosure can be used to seal closures. A closure can be a closure on the surface of a vehicle, including, for example, motor vehicles, automobiles, trucks, buses, vans, motorcycles, scooters, recreational motor vehicles; rail vehicles, trains, trams, bicycles, aerospace vehicles, airplanes, rockets, spacecraft, jets, helicopters, military vehicles including jeeps, transports, combat support vehicles, personnel carriers, infantry fighting vehicles, mine protected vehicles, light armored vehicles, light utility vehicles, military trucks, boats, boats and pleasure craft. Closures sealed by a multilayer system provided by the present disclosure are included within the scope of the invention. I br1 n / L7n7 / q / YIAI ASPECTS OF THE INVENTION The invention may be further defined by one or more of the following aspects. Aspect 1. A method of manufacturing a multilayer system comprising two or more layers, wherein one or more of the layers comprises a sealant layer, comprising: (a) mixing a first component and a second component to form a composition coreactive sealant, wherein the coreactive sealant composition comprises a first reactive compound and a second reactive compound; and the first reactive compound is reactive with the second reactive compound; (b) extruding the coreactive sealant composition to form an extrudate; and (c) depositing the extrudate to form the sealant layer. Aspect 2. The method according to aspect 1, wherein the deposition comprises three-dimensional printing. Aspect 3. The method of any of the aspects 1 to 2, wherein the depositing comprises depositing the extrudate on an underlying layer of the multilayer system. Aspect 4. The method of any of aspects 1 to 3, further comprising: depositing a first coreactive composition below the deposited sealer layer to form an underlying layer; and / or depositing a second coreactive composition on top of the sealant layer to form an overlay, wherein the first coreactive composition and the second coreactive composition comprise a different composition than the sealant layer. Aspect 5 The method of Aspect 4, wherein the first coreactive composition is different from the second coreactive composition. Aspect 6. The method of any of the aspects 1 to 5, wherein any of the coreactive sealant compositions comprises a thermosetting composition. Aspect 7. The method of any of the aspects 1 to 6, wherein each of the layers of the multilayer system comprises a thermoset. Aspect 8. The method of any of the aspects 1 to 7, wherein a cross section of the extrudate has a homogeneous composition along the cross section. Aspect 9. The method of any of the aspects 1 to 7, wherein a cross section of the extrudate has an inhomogeneous composition along the cross section. Aspect 10. The method of any of the aspects 1 to 9, wherein an outermost layer of the two or more layers of the multilayer system comprises a sealant layer. Aspect 11. The method of any of the aspects 1 to 10, wherein each of the layers of the multilayer system independently comprises a sealer layer or a non-sealer layer. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ Aspect 12. The method of any of Aspects 1 to 11, wherein the coreactive sealant composition comprises a prepolymer comprising a chemically resistant backbone. Aspect 13. The method of any of Aspects 1 to 12, wherein the coreactive sealant composition comprises a sulfur content greater than 10% by weight, wherein the % by weight is based on the total weight of organic constituents of the corrective sealing composition. Aspect 14. The method of any of Aspects 1 to 13, wherein the co-reactive sealant composition comprises a sulfur-containing prepolymer. Aspect 15. The method of aspect 14, wherein the sulfur-containing prepolymer comprises a polyethylene, a polysulfide, a sulfur-containing polyform, a monosulfide, or a combination of any of the foregoing. Aspect 16. The method of any of the aspects 14 to 15, wherein the sulfur-containing prepolymer comprises a sulfur content greater than 10% by weight, wherein the % by weight is based on the total weight of the prepolymer containing contains sulfur. Aspect 17. The method of any of the aspects 1 to 16, wherein the first reactive compound is reactive with the second reactive compound at a temperature of less than 50°C. Aspect 18. The method of any of the aspects 1 to 17, wherein, the first reactive compound is reactive with the second reactive compound in the presence of a catalyst and / or a polymerization initiator; and the polymerization catalyst and / or initiator is capable of catalyzing and / or initiating a reaction between the first reactive compound and the second reactive compound. Aspect 19. The method of any of Aspects 18 further comprises activating the polymerization initiator prior to depositing, during deposition, and / or after depositing the extrudate. Aspect 20. The method of any of the aspects 1 to 19, wherein, the first component comprises the first reactive compound and the second reactive compound; and the second component comprises a catalyst, a cure activator, and / or a polymerization initiator for the reaction between the first reactive compound and the second reactive compound. Aspect 21. The method of any of the aspects 1 to 19, wherein the first component comprises the first reactive compound and the second component comprises the second reactive compound. Aspect 22. The method of any of the aspects 1 to 21, in which, the I br1 n / I 7Π7 / 3 / ΥΙΛΙ first reactive compound comprises a polyamine and / or a polyol and the second reactive compound comprises a polyisocyanate; the first reactive compound comprises a polyamine and the second reactive compound comprises a polyepoxide; the first reactive compound comprises a Michael acceptor and the second reactive compound comprises a Michael donor; or the first reactive compound comprises a polythiol and the second reactive compound comprises a polythiol, a polyisocyanate, a polyalkenyl, a polyepoxide, a Michael acceptor, or a combination of any of the foregoing. Aspect 23. The method of any of the aspects 1 to 22, further comprises: pumping the first component in a mixer using a first pump; and pumping the second component into the mixer using a second pump. Aspect 24. The method of any of the aspects 1 to 23 further comprises, after depositing the extrudate, curing the deposited extrudate. Aspect 25. The method of aspect 24, wherein the curing comprises allowing the deposited extrudate to cure at a temperature below 30°C. Aspect 26. The method of any of Aspects 1 to 25 further comprises fusing one or more additional coreactive compositions with the coreactive sealant composition, wherein the extrusion comprises coextruding the coreactive sealant composition and the one or more additional coreactive compositions to form a coextrudate; and depositing comprises depositing the coextrudate to form a multilayer system comprising one or more senator layers. Aspect 27. The method of aspect 26, wherein each of the one or more additional coreactive compositions independently comprises an additional coreactive sealant composition or a coreactive non-sealant composition. Aspect 28. The method of any of Aspects 26 to 27, wherein the coreactive sealer composition and an adjacent additional coreactive composition comprise the same curing chemistry. Aspect 29. The method of any of Aspects 26 to 28, wherein the coreactive sealant composition and an adjacent additional coreactive composition comprise different curing chemistries. Aspect 30. The method of any of aspects 26 to 29, wherein the coreactive sealant composition is reactive with an adjacent additional coreactive composition. Aspect 31. The method of any of aspects 26 to 30, further comprising: combining an additive-containing composition with a portion of an additional coreactive composition to form an additional additive-modified coreactive composition, wherein the additive-containing composition comprises an additive; and the extrusion comprises I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ co-extrude the coreactive sealant composition and the additional coreactive composition modified with additives to form a coextrudate. Aspect 32. The method of aspect 31, wherein a cross section of the coextrudate has an inhomogeneous concentration of the additive. Aspect 33. The method of any of aspects 31 to 32, wherein the extrudate is characterized by an inhomogeneous concentration of the additive within a longitudinal dimension of the coextrudate. Aspect 34. The method of any of aspects 26 to 33 further comprises mixing a third component with a fourth component to form the one or more additional coreactive compositions. Aspect 35. The method of any of Aspects 1 to 34, further comprising: combining an additive-containing composition with a portion of the coreactive sealant composition to form an additive-modified coreactive sealant composition, wherein the additive-containing composition comprises an additive; and extruding the additive-modified coreactive sealant composition to form the extrudate. Aspect 36. The method of Aspect 35, wherein a cross section of the extrudate has an inhomogeneous concentration of the additive. Aspect 37. The method of any of aspects 35 to 36, wherein the extrudate is characterized by an inhomogeneous concentration of the additive within a longitudinal dimension of the extrudate. Aspect 38. The method according to any of the aspects 1 to 37, further comprising fusing an adhesion promoting composition with the coreactive sealant composition; and the extrusion comprises coextruding the first coreactive composition and the adhesion promoting composition. Aspect 39. The method according to any of aspects 1 to 38, further comprising applying an adhesion promoting layer to the extrudate before depositing the extrudate. Aspect 40. A multi-layer system comprising a sealant layer manufactured by the method according to any of the aspects 1 to 39. Aspect 41. The multilayer system according to aspect 40, where the adjacent layers are chemically and / or physically bonded. Aspect 42. The multilayer system according to any of Aspects 40 to 41, wherein the fracture energy of the fully cured multilayer sealant is substantially the same as the fracture energy of an individual layer, wherein the fracture energy is determined in accordance with ASTM D7313. I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ Aspect 43. The multilayer system according to any of aspects 40 to 42, wherein each of the layers comprises a thermosetting material. Aspect 44. The multilayer system according to any of aspects 40 to 43, wherein each of the layers comprises a different thermosetting material. Item 45. The multi-coat system according to any of items 40 to 44, wherein the multi-coat system meets or exceeds the requirements for aerospace sealants as set forth in AMS 3277. Aspect 46. The multi-layer system according to any of aspects 40 to 45, wherein one or more of the layers of the multi-layer sealant has a cross-sectional profile of inhomogeneous composition. Aspect 47. The multi-layer system according to any one of aspects 40 to 46, wherein one or more of the layers of the multi-layer sealant has an inhomogeneous composition in the longitudinal dimension. Aspect 48. A part comprising the multilayer system according to any of aspects 40 to 47. Aspect 49. The part according to aspect 48, wherein the part comprises a motor vehicle part or an aerospace vehicle part. Aspect 50. A vehicle comprising the multilayer system according to any of the aspects 40 to 47. Aspect 51. The vehicle according to aspect 50, wherein the vehicle comprises an aerospace vehicle or a motor vehicle. EXAMPLES The embodiments provided by the present disclosure are further illustrated with reference to the following examples, which describe methods for making multilayer systems and properties of multilayer systems. It will be apparent to those in the mid-level trade that many modifications, both in materials and methods, can be implemented without departing from the scope of the disclosure. EXAMPLE 1 Synthesis of thiol-terminated polyepoxy extended copolymer A thiol-terminated polythioether polymer, Permapol® P3.1E, (384.32 g, commercially available from PPG Aerospace, mercaptan equivalent weight 1650) and a I br / n / I 7Π7 / 3 / ΥΙΛΙ polyepoxy, DEN® 431 (8.45 g, available from Dow Chemical) were combined in a plastic cup. The components were combined using a mixer (Hauschild Speed ​​Mixer, 2300 rpm, 45 seconds). An amine, Dabco® 33-LV, (5.38 g, available from Air Products & Chemicals) was added to the mixture and mixed using a high speed mixer (Hauschild SpeedMixer®, 30 s at 2300 rpm and 5 min at 800 rpm). The resulting extended polyepoxide prepolymer was left at 23°C for 24 hours before being combined with other constituents to prepare a coreactive sealant composition. The thiol-extended polyepoxide prepolymer had a number average molecular weight of 4,716 Da, and a thiol equivalent weight of 2,069 Da. EXAMPLE 2 Preparation of Skvdrol® resistant polyether sealant. A base coreactive component (Part B) was prepared comprising the thiol-extended polyepoxide prepolymer of Example 1. The components listed in Table 1 were combined and mixed to form the Base component (Part B). I bp 1 η / I 7Π7 / 3 / ΥΙΛΙ TABLE 1 Basic component of the activity (Part Bl Constituent Material Quantity (wt%) Thiol-terminated chain-extended prepolymer Thiol-extended polyepoxide prepolymer of Example 1 61.62 Organic filler Micronized polyolefin, ACumist® A-6 1 6.08 Organic filler Ganzpearl® 2 24.65 Filler Inorganic Calcium Carbonate, Socal® 31 3 2.50 Inorganic Filler Agent Silica Fumed, Aerosil® R202 4 3.08 Baked Phenolic Adhesion Promoter, T-3920 5 0.42 Baked Phenolic Adhesion Promoter, T-3921 5 0.33 Silquest® A Adhesion Promoter -1110 Alkylosilane6 0.5 Adhesion Promoter Phenolic Resin, Methylon® 75108 7 0.83 1Commercially available from Honeywell, Morris Plains, NJ. 2Available from Sakai Trading, New York, NY. 3Commercially available from Solvay. 4Commercially available from Cabot Corp. 5Commercially available from PPG Aerospace, Sylmar, CA. 6Available from Momentive. 7Commercially available from Durez Corp. An accelerator component (Part A) was prepared comprising a polyepoxide curing agent. The components of the Accelerator (Part A) are shown in Table 2. TABLE 2 Accelerator composition (part Al I bP1 Π / I 7Π7 / 3 / ΥΙΛΙ Constituent Material Amount (% by weight) DER®331 Polyepoxide 1 21.42 EPU-73B Polyepoxide 2 7.14 Epoxy Terminated Polyether Polyepoxide 3 21.91 DEN® 4314 Novolac Epoxy Polyepoxide 9.09 Inorganic Filling Agent Calcium Carbonate, Winnodil® SPM 5 40.37 Sunfast® Pigment Blue tint6 0.07 1Commercially available from the Dow Chemical. 2Polyurethane polyepoxide; epoxy equivalent weight 245; commercially available from Adeka Corporation, Tokyo, Japan. 3Difunctional polyethylene with epoxy finish; epoxy equivalent weight. 584; commercially available from PPG Aerospace, Sylmar, CA. 4Commercially available from the Dow Chemical. 5Commercially available from Solvay. 6Commercially available from Sun Chemical Corp. A Skydrol® LD-4 resistant coreactive sealant composition was prepared by mixing 100 parts of the Base component (Part B) with 15.3 parts of the Accelerator component (Part A). EXAMPLE 3 multilayer system A multi-coat system was made by first preparing a first inner coat comprising a sealer and then applying a second outer coat over the first inner coat. The material used to prepare the first inner layer was not resistant to Skydrol® LD-4. An interior layer was prepared by cutting samples of cured PR-2001 or PR-1776M sealant into 2 inch x 2 inch x 0.25 inch blocks. Both the PR-2001 and PR1776M are commercially available from PPG Aerospace. PR-2001 is a two-part, epoxy-cured sealer based on thiol-terminated Permapol® 3.1 prepolymers. PR-1776M is a two component, manganese dioxide cured, Class B sealant based on Permapol® P-5 modified polysulfide. The inner sealant blocks were then coated with a layer of the Skydrol® resistant coreactive sealant composition of Example 2 varying in thickness from 1mm to 4mm to provide an outer layer. The outer layer covered the top, bottom, and sides of the blocks, and was then cured. The multilayer systems (Multilayer Systems 1-4) were immersed in Skydrol® LD-4 between 1 and 5 days at 70°C and the Shore A hardness of the blocks was measured periodically. Skydrol® LD-4 is a fire resistant hydraulic fluid based on phosphate ester chemistry available from Eastman Chemical Company. Skydrol® LD-4 has a concentration of approximately 58.2% by weight of tributyl phosphate, of approximately 20% to 30% by weight of dibutyl phenylphosphate, of approximately 5% to 10% by weight of butyl diphenyl phosphate, less from about 10% by weight of 2-ethylhexyl-7oxabicyclo[4.1.0]-heptane-3-carboxylate and from about 1% by weight to 5% by weight of 2,6-di-tert-butyl-p-cresol. Hardness was determined according to ASTM D2240. The hardness of control sealants consisting of sealant blocks PR-2001 (Sealant Cl) or PR1776M (Sealant C2) without the Skydrol® resistant sealant layer of Example 2 was also measured at intervals during immersion in Skydrol® LD. -4 to 70°C The results are shown in Table 3. The results demonstrate that a multi-coat system including a sealer coat showed higher resistance to Skydrol® LD-4 than a single coat sealer. I 1 n / L7n7 / q / YIAI TABLE 3 Shore A hardness of the multilayer system after immersion in Skydrol® LD-4 at 70°C. Multi-layer sealant Interior sealant Second layer thickness (mm) Initial Shore A hardness After immersion of Skydrol® LD-4 at 70°C 1 day 2 days 3 days 5 days 1 PR-2001 1 64A 43A 37A 33A 32A 2 PR -1776M 1 63A 44A 36A 31A 28A 3 PR-2001 4 64A 42A 37A 36A 33A 4 PR-1776M 4 60A 38A 38A 34A 31A C1 PR-2001 0 56A 34A 26A 26A 25A C2 PR-1776M 0 50A 17A 2A too soft to measure too soft to measure Finally, it should be noted that there are alternative ways of implementing the embodiments disclosed herein. Accordingly, the present embodiments are to be considered illustrative and not limiting. In addition, claims should not be limited to the details stated herein and are entitled to their full scope and their equivalents.

Claims

1. A method of manufacturing a multilayer system comprising two or more layers, wherein one or more of the layers comprises a sealing layer, comprising: (a) mixing a first component and a second component to form a first co-reactive sealing composition, wherein the co-reactive sealing composition comprises a first reactive compound and a second reactive compound; and the first reactive compound is reactive with the second reactive compound; (b) extruding the first co-reactive sealing composition to form an extrudate; (c) depositing the extrudate to form the sealing layer; and (d) depositing a second co-reactive composition beneath the deposited sealing layer to form an underlying layer.and / or depositing a third correactive composition overlying the sealing layer to form an overlying layer, wherein the second correactive composition and the third correactive composition comprise a composition different from the sealing layer, wherein the deposition comprises three-dimensional printing coextrusion.; 2. The method according to claim 1, wherein the first coreactive composition is different from the second coreactive composition.

3. The method according to any of claims 1 to 2, wherein each of the layers of the multilayer system comprises a thermoset.

4. The method according to any of claims 1 to 3, wherein a cross-sectional profile of the extrudate has a homogeneous composition along the cross-sectional profile.

5. The method according to any of claims 1 to 4, wherein a cross-sectional profile of the extrudate has a non-homogeneous composition along the cross-sectional profile.

6. The method according to any of claims 1 to 5, wherein an outermost layer of the two or more layers of the multilayer system comprises a sealing layer.

7. The method according to any of claims 1 to 6, wherein the coreactive sealing composition comprises a sulfur-containing prepolymer.

8. The method according to any of claims 1 to 7, wherein the first reactive compound is reactive with the second reactive compound at a temperature below 50°C.

9. The method according to any of claims 1 to 8, further comprising fusing one or more additional co-reactive compositions with the co-reactive sealing composition, wherein the extrusion comprises co-extruding the co-reactive sealing composition and one or more additional co-reactive compositions to form a co-extrudate; and the deposition comprises depositing the co-extrudate to form a multi-layer system comprising one or more sealing layers.

10. The method according to claim 9, wherein each of the coreactive sealing compositions is reactive with an adjacent coreactive composition.

11. The method according to any one of claims 1 to 10, further comprising: combining a composition containing additives with a portion of the core-reactive sealing composition to form a core-reactive sealing composition modified with additives, wherein the composition containing additives comprises an additive; and extruding the core-reactive sealing composition modified with additives to form the extrudate, wherein a cross-sectional profile of the extrudate has a non-homogeneous concentration of the additive; and / or wherein the extrudate is characterized by a non-homogeneous concentration of the additive within a longitudinal dimension of the extrudate.

12. The method according to any of claims 1 to 11, further comprising fusing an adhesion-promoting composition with the core-reactive sealing composition; and the extrusion comprises co-extruding the first core-reactive composition and the adhesion-promoting composition.

13. A multilayer system comprising a sealing layer made by the method according to any of claims 1 to 12.

14. The multilayer system according to claim 13, wherein the adjacent layers are chemically and / or physically bonded.

15. The multilayer system according to any of claims 13 to 14, wherein each of the layers comprises a thermoset material.

16. The multilayer system according to any of claims 13 to 15, wherein the multilayer system meets or exceeds the requirements for aerospace senators as set forth in AMS 3277.

17. The multilayer system according to any of claims 13 to 16, wherein one or more of the layers of the multilayer sealant have a cross-sectional profile of non-homogeneous composition.

18. The multilayer system according to any of claims 13 to 17, wherein one or more of the layers of the multilayer sealant has a non-homogeneous composition in the longitudinal dimension.

19. A part comprising the multilayer system according to any of claims 13 to 18.

20. The part according to claim 19, wherein the part comprises an automotive vehicle part or an aerospace vehicle part.

21. A vehicle comprising the multilayer system according to any of claims 13 to 18.