Catalytic compositions and thiol-based compositions with extended pot life

Abstract

This invention relates to catalytic compositions and curable compositions containing said catalytic compositions. The catalytic compositions of this invention essentially consist of: (i) a metal compound; and (ii) a compound different from (i), said compound catalyzing an addition reaction between an alkene-bonded unsaturated compound and a thiol, wherein said catalytic composition is substantially free of vanadium compounds. The curable compositions according to this invention comprise: (a) a polyene, (b) a polythiol, and (c) a catalytic component, said catalytic component being composed of the aforementioned catalytic compositions.

Description

[0001] This application is a divisional application of application number 201980084099.9, filed on December 17, 2019, entitled "Catalytic Composition and Thiol-Based Composition with Extended Potential Life". Technical Field

[0002] This invention relates to catalytic compositions and curable compositions having an extended pot life, the curable compositions comprising polyenes, polythiols, and the catalytic composition. Background Technology

[0003] Catalysis is the process by which a chemical reaction is initiated or its rate is altered by the participation of a material called a catalyst. A catalyst that accelerates a reaction is called a positive catalyst. A catalyst that slows down a reaction is called a negative catalyst or inhibitor. Unlike reactants, catalysts are not consumed by the reaction themselves.

[0004] Catalysts function by providing an alternative reaction pathway from reactants to products. When the activation energy of this alternative pathway is lower than that of the uncatalyzed reaction pathway, the reaction rate increases. Catalysts can also enable reactions that would otherwise be blocked or slowed down by thermodynamic or kinetic barriers. Catalysts can increase the reaction rate or selectivity of reactants or allow the reaction to continue at temperatures lower than would otherwise be possible. Therefore, catalysts can be invaluable tools in industrial chemical processes.

[0005] However, the use of catalysts also has drawbacks. For example, tin compounds are widely used as catalysts for isocyanate / hydroxyl reactions in industrial products such as coatings. Amine compounds are used as catalysts for polyene / thiol reactions. Unfortunately, the levels of these catalysts required to provide acceptablely rapid curing rates and end-product properties often result in a relatively short application time window after reactant mixing.

[0006] Therefore, timely processing is required to ensure that the mixed components maintain a sufficiently low viscosity for application to a substrate, such as by spraying. The time span during which a coating is ready for application to a substrate and still has a sufficiently low viscosity for application is generally referred to as the "fit period." This will be defined more quantitatively below.

[0007] The pot life must generally be balanced with the curing rate of the applied coating. For example, in multi-component coating systems using catalysts, both pot life and curing rate are primarily controlled by the amount of catalyst present. Therefore, if a faster curing rate is required, more catalyst can be used, but this will also result in a shorter pot life. Conversely, if a longer pot life is required, less catalyst can be used, but the curing rate will be slower.

[0008] Equally important is that the applied coating composition dries and hardens rapidly, minimizing contamination and ensuring that valuable shop space is not occupied by the coated substrate, such as a car, while the coating is drying. The time between coating application to a substrate and coating drying or curing sufficiently so that dust or other debris falling onto the coated substrate will not adhere to it is called the "dust-free time" or "stick-free time" and is an indicator of curing speed. One way to accelerate the drying and curing of the composition is to add additional catalysts, but this will shorten the time available for treatment, such as by spraying, because higher catalyst levels also cause the viscosity of the composition to increase more rapidly with increasing reaction rate.

[0009] Polyenes containing unsaturated groups such as acryloyl groups react with compounds containing active hydrogen. This reaction is believed to involve the addition of an anion derived from a nucleophilic active hydrogen compound to an activated unsaturated group, where the anion acts as a donor and the activated unsaturated group acts as an acceptor. When these active hydrogen compounds are CH compounds such as malonates or acetoacetates, the reaction is called a Michael addition reaction. It is also known that SH-containing compounds can act as active hydrogen compounds in a reaction mechanism similar to the Michael addition reaction. This reaction mechanism utilizing SH-containing compounds is called the thiol-ene reaction.

[0010] Catalysts used for thiolide reactions include amine compounds, such as tetramethylguanidine, diazabicycloundecene, and diazabicyclononene. Thiollide reactions catalyzed by these strong bases can be difficult to control, and such reaction mixtures typically have a short pot life.

[0011] It would be desirable to use catalysts that overcome these drawbacks of the prior art to catalyze the chemical reaction between polyenes and thiols by extending the pot life of the composition and / or accelerating the reaction rate of the thiols after application, such as to achieve a shorter tack-free time, without negatively impacting the pot life of the composition and / or the chemical resistance of the coating derived from the composition. Summary of the Invention

[0012] It has now been discovered that these objectives can be achieved by using certain catalytic compositions. The catalytic compositions of the present invention essentially consist of the following:

[0013] (i) metal compounds; and

[0014] (ii) A compound that catalyzes the addition reaction between an olefinically unsaturated compound and a thiol. The catalytic compositions of the present invention are substantially free of, or completely free of, vanadium compounds. Compound (ii) is different from the metal compound (i). Therefore, the catalytic compositions according to the present invention comprise two different types of compounds. The catalytic compositions are generally substantially free of, or completely free of, reactive compounds including acid functional groups, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polybasic acids. The connecting phrase “substantially composed of” means that the composition is limited to the specified materials or steps “and not”. essentially One or more of the following factors affect the claimed invention: Basic and novel "Those with characteristics." In re Herz, 537F.2d 549,551-52,190 USPQ 461,463 (CCPA 1976) (emphasized in the original).

[0015] The present invention also relates to curable compositions comprising:

[0016] (a) Polyene;

[0017] (b) a polythiol, wherein the polythiol is present in an amount greater than 10% by weight based on the total weight of the resin solids in the curable composition; and

[0018] (c) Catalytic component, which consists of the catalytic composition according to the invention described above and in more detail below. Detailed Implementation

[0019] For the purposes of the following detailed description, it should be understood that the invention may take various alternative variations and sequences of steps unless expressly indicated to the contrary. Furthermore, all figures expressing quantities of ingredients, such as those used in this specification and claims, should be understood to be modified in all cases by the term "about," except in any operational instance or where otherwise indicated. Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending on the desired properties to be obtained by the invention. At least, and without attempting to limit the application of the doctrine of equivalence to the scope of the claims, each numerical parameter should be interpreted at least according to the number of significant figures reported and by applying ordinary rounding techniques. While the numerical ranges and parameters illustrating the broad scope of the invention are approximations, the values ​​set forth in specific examples are reported as precisely as possible. However, any numerical value inherently contains some error necessarily caused by the standard deviation found in its corresponding test measurement.

[0020] It should also be understood that any numerical range stated herein is intended to include all subranges included therein. For example, the range “1 to 10” is intended to include all subranges between the stated minimum value 1 and the stated maximum value 10 (and includes both the maximum and the minimum value), that is, a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0021] In this application, unless otherwise specifically stated, the use of the singular includes the plural, and the plural encompasses the singular. Additionally, in this application, unless otherwise specifically stated, the use of "or" means "and / or," but "and / or" may be used explicitly in certain circumstances. It should be noted that the phrase "and / or," when used in a list, is intended to cover alternative embodiments that include each individual component in the list as well as any combination of components. For example, the list "A, B, and / or C" is intended to cover seven individual embodiments including A, or B, or C, or A+B, or A+C, or B+C, or A+B+C.

[0022] Unless otherwise instructed, molecular weights will be reported as number-average molecular weights relative to polystyrene standards, determined by gel permeation chromatography, in g / mol.

[0023] As described above, the catalytic composition of the present invention contains (i) a metal compound. Suitable metal compounds include at least one of metal oxides, metal salts (including organic and inorganic salts), and organometallic compounds. Metals that may be present in metal compound (i) include, for example, iron, tin, cobalt, magnesium, manganese, and mixtures thereof. Metal compound (i) present in the catalytic composition according to the present invention often includes iron compounds. Exemplary metal compounds include, for example, iron (II) and iron (III) compounds such as iron oxides, ferrous acetate or ferric acetate, and metal halides such as ferric chloride and ferrous chloride.

[0024] The catalytic composition of the present invention further comprises (ii) a compound that catalyzes the addition reaction between an alkene-bonded unsaturated compound and a thiol. Catalytic compound (ii) may, for example, include a base. Catalytic compound (ii) may, for example, include an organic compound having one or more nitrogen atoms and / or phosphorus atoms. Suitable catalytically active compound (ii) comprises, for example, primary amines, secondary amines, and tertiary amines, as well as phosphine. Specific, non-limiting examples of such compounds include, for example, oxazolidinyl, triethylamine, dimethylhexylamine, dimethylcyclohexylamine, dimethyloctylamine, dimethyldodecaneamine, dimethylaminoethanol and other dimethylamino alcohols, tetramethylguanidine, diazabicyclooctane, diazabicycloundecene, diazabicyclononene, n-methyltriazabicyclodecene, trioctylphosphine, and triphenylphosphine.

[0025] Compound (ii) may include substituted carbonates. For example, quaternary ammonium and phosphonium carbonates are suitable. Specific examples include tetrahexylmethylammonium carbonate, tetrahexylammonium bicarbonate, tetradecyl-trihexylmethylammonium carbonate, and tetradecylmethylammonium carbonate. Such substituted carbonates are described in paragraphs

[0032] through

[0039] of U.S. Patent Application Publication No. 2013 / 0210986. Any combination of the mentioned compounds may also be used where appropriate.

[0026] Typically, the molar ratio of nitrogen (as in an amino or ammonium group) or phosphorus (as in a phosphine or phosphonium group) in compound (ii) to the metal in metal compound (i) is from 0.4 to 500:1, such as from 1 to 100:1 or from 25 to 75:1. For example, when metal compound (i) includes an iron compound and compound (ii) includes a compound containing a secondary or tertiary amino group, the molar ratio of amino group (and therefore N) to iron is from 0.4 to 500:1, such as from 0.9 to 30:1 or from 1 to 10:1 or from 25 to 75:1.

[0027] The catalytic compositions of the present invention are substantially free of, and may be completely free of, vanadium compounds. Furthermore, the catalytic compositions may be substantially free of, or completely free of, reactive compounds comprising acid functional groups or groups that can be converted into acid functional groups through suitable chemical reactions. Examples of such reactive compounds include acid anhydrides, acids (including, for example, carboxylic acids, phosphonic acids, or sulfonic acids), or reaction products of active hydrogen compounds with acid anhydrides or polybasic acids. “Substantially free of” a material means that the composition contains only trace or incidental amounts of a given material, and the amount of said material present is insufficient to affect any property of the composition. These materials are not essential to the composition, and therefore, the composition does not contain any substantial or necessary amounts of these materials. Furthermore, said materials can substantially affect one or more fundamental and novel properties of the invention because they can exhibit catalytic activity. If said materials are present, they are only incidental, typically less than 0.1% by weight, such as less than 0.05% by weight or less than 0.01% by weight, based on the total weight of solids in the composition. “Completely free of” as used herein means that the composition does not contain at all, or at least does not contain the stated material in a measurable amount.

[0028] The catalytic compositions of this invention can be used to extend the pot life as defined below, while simultaneously providing rapid curing time for various curable compositions, specifically compositions undergoing thiol-ene reactions. The catalytic compositions of this invention are more effective than conventional catalysts in extending the pot life of compositions undergoing thiol-ene reactions. These curable compositions are often used as automotive refinish coatings because they can react and cure at ambient temperatures. “Ambient” means the surrounding environmental conditions without regulation of temperature, humidity, or pressure. Ambient temperatures typically range from 40℉ to 95℉ (approximately 4°C to 35°C), often from 60℉ to 95℉ (approximately 15°C to 35°C), such as a typical room temperature of 72℉ (22.2°C).

[0029] The catalyst compositions of the present invention can also be used to extend the pot life and provide rapid curing times for thiol ene reactions in aerospace coatings and sealant systems based on thiol ene curing chemistry. Coatings and sealants suitable for aerospace applications must meet many demanding performance requirements, including resistance to aerospace fluids. Prepolymers having sulfur groups such as polysulfides, polysulfides, and sulfur-containing polyformaldehydes in the main chain can be advantageously used in aerospace coatings and sealants. These sulfur-containing prepolymers can react with polyenes in the presence of an amine catalyst to provide cured coatings or sealants for aerospace applications. Compositions comprising thiol-terminated sulfur-containing prepolymers and polyenes such as acrylates are disclosed in U.S. Application Publication No. 2006 / 0270796 and are suitable for use in the curable compositions of the present invention described below. Compositions comprising thiol-terminated sulfur-containing prepolymers are disclosed in U.S. Patent Application Publications 2013 / 0343371, 2014 / 0378649, 2015 / 0119549, 2015 / 0252233, 2013 / 0345389, 2015 / 0099858, and 2015 / 0252232 and are suitable for use in the curable compositions of the present invention. Compositions comprising thiol-terminated sulfur-containing prepolymers suitable for use in aerospace sealant applications and thiol olefin curing chemistry are disclosed, for example, in U.S. Patent Application Publications 2012 / 00401303 and 2014 / 0186543 and are suitable for use in the curable compositions of the present invention. The term “polymer” is also intended to include copolymers, oligomers, and prepolymers; that is, materials whose molecular weight can be increased by chain extension.

[0030] The present invention also relates to curable compositions comprising:

[0031] (a) Polyene,

[0032] (b) Polythiols, and

[0033] (c) A catalytic component comprising the catalytic composition of the present invention as described above. As used herein, the terms “catalytic component” or “catalytic composition” uniformly refer to all materials disclosed above that, individually or in some combination with one or more other materials, have a catalytic effect on the reaction of polyenes (a) and polythiols (b), i.e., influence the reaction kinetics without being permanently consumed by the reaction. While not wishing to be bound by theory, it is believed that the metal compound (i) provides “surface curing” to the composition; for example, when the curable composition is applied as a coating to a substrate, the metal compound (i) catalyzes the curing of the coating composition at the outermost region of the coating layer opposite the substrate surface and exposed to air. Similarly, when the curable composition is molded or otherwise shaped into an article, the metal compound (i) catalyzes the curing of the composition on its surface. It is further believed that the compound (ii) provides “through cure” to the composition, the compound curing through the majority of the composition.

[0034] There are many polyenes (a) suitable for use in the curable compositions of the present invention, and they can vary widely. Such polyenes may include those known in the art. Non-limiting examples of suitable polyenes may include those represented by the following formula:

[0035] A-(X) m

[0036] Wherein A is an organic moiety, X is an olefinic unsaturated moiety, an alkynyl group, and / or a Michael acceptor group, and m is at least 2, typically 2 to 6. Organic moiety A may include C, H, and heteroatoms. Organic moiety A may include one or more groups, for example, selected from ester and urethane groups. Organic moiety A may be derived, for example, from polyisocyanates, such as polyurethane (meth)acrylates and polyurethanes containing (meth)allyl groups as described below. Non-limiting examples of X are groups having the following structures:

[0037]

[0038] Each R is selected from H and methyl. It should be noted that “acrylic acid” and “methacrylic acid” are referred to herein as “(meth)acrylic acid” in a summary manner. Similarly, “allyl” and “methylallyl” are referred to herein as “(meth)allyl” in a summary manner. The phrase “derived from polyisocyanate” refers herein to the portion produced by the reaction of the isocyanate group -N=C=O of the polyisocyanate with a group reactive to the isocyanate group (such as a hydroxyl group). Similarly, as in the statement “R1 derived from polyol”, “derived from polyol” refers to the portion produced by the reaction of the alcohol hydroxyl group -OH of the polyol with a group reactive to the hydroxyl group (such as a carboxyl group).

[0039] Suitable polyenes comprise compounds or polymers having olefinic double bonds in their molecules that can polymerize, for example, through exposure to radiation. Examples of such materials are (meth)acrylic acid-functionalized (meth)acrylic acid copolymers, epoxy (meth)acrylic acid esters, polyester (meth)acrylic acid esters, polyether (meth)acrylic acid esters, polyurethane (meth)acrylic acid esters, amino (meth)acrylic acid esters, silicone (meth)acrylic acid esters, and melamine (meth)acrylic acid esters, among which polyester (meth)acrylic acid esters and polyurethane (meth)acrylic acid esters are particularly useful. The number average molecular weight (M) of these compounds is... n The number is typically around 200 to 10,000. Suitable polyenes generally contain an average of 2 to 20 olefinic double bonds per molecule that can polymerize, for example, through exposure to radiation. Aliphatic and / or cycloaliphatic (meth)acrylates are commonly used. “Aliphatic” and “cycloaliphatic” are referred to herein in a summary manner as “(cyclo)aliphatic”. (cyclo)aliphatic polyurethane (meth)acrylates and (cyclo)aliphatic polyester (meth)acrylates are particularly suitable. Any combination of polyenes such as those mentioned herein can also be used as polyene(a) in the curable compositions according to the invention.

[0040] As mentioned above, polyurethane (meth)acrylates are suitable for use as polyenes (a). Examples of polyurethane (meth)acrylates include reaction products of polyisocyanates such as 1,6-hexamethylene diisocyanate and / or isophorone diisocyanate (including isocyanurate and its biuret derivatives) with hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate and / or hydroxypropyl (meth)acrylate. Polyisocyanates can react with hydroxyalkyl (meth)acrylates at a 1:1 NCO / OH equivalent ratio or at an NCO / OH equivalent ratio greater than 1:1 to form NCO-functionalized reaction products that can then be chain-extended with polyols such as diols or triols such as 1,4-butanediol, 1,6-hexanediol and / or trimethylolpropane.

[0041] Polyester (meth)acrylates are also suitable as products of the reaction of polyenes (a) and containing, for example, (meth)acrylic acid or (meth)acrylic anhydride with polyols such as diols, triols, tetraols, and higher polyols (including alkylated polyols such as propoxylated diols and triols). Examples of suitable polyols include glycerol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol, and propoxylated 1,6-hexanediol. Specific examples of suitable polyester (meth)acrylates are, for example, glycerol tri(meth)acrylate, trimethylpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol penta(meth)acrylate.

[0042] (Meth)allyl compounds or polymers can also be used alone or in combination with (meth)acrylate compounds as described above as polyenes (a) in the curable compositions according to the invention. Examples of (meth)allyl materials are polyallyl ethers, such as diallyl ether of 1,4-butanediol and triallyl ether of trimethylolpropane. Other examples of (meth)allyl compounds are (meth)allyl-containing polyurethanes comprising reaction products of polyisocyanates such as 1,6-hexamethylene diisocyanate and / or isophorone diisocyanate (containing isocyanurate and its biuret derivatives) with hydroxyl-functionalized allyl ethers such as monoallyl ether of 1,4-butanediol and diallyl ether of trimethylolpropane. Polyisocyanates can react with hydroxyfunctional allyl ethers at a 1:1 NCO / OH equivalent ratio or at a greater than 1:1 NCO / OH equivalent ratio to form an NCO-containing reaction product that can then be chain-extended with polyols such as diols or triols such as 1,4-butanediol, 1,6-hexanediol and / or trimethylolpropane.

[0043] As mentioned above, polyenes (a) may also include one or more Michael acceptor groups. A "Michael acceptor group" refers to an alkenyl / alkynyl moiety in which one or more electron-withdrawing groups, such as carbonyl (-C=O), nitro (-NO2), nitrile (-CN), alkoxycarbonyl (-COOR), phosphonate (-PO(OR)2), trifluoromethyl (-CF3), sulfonyl (-SO2-), p-toluenesulfonyl (-SO2-C6H4-CH3), etc., are directly bonded to carbon atoms in a carbon-carbon double or triple bond. Compounds containing Michael acceptor groups include, for example, ketene, quinone, nitroene, acrylonitrile, acrylate, methacrylate, cyanoacrylate, acrylamide, maleimide, dialkylvinylphosphonate, and vinyl sulfone. Other examples of Michael acceptors are disclosed in Mather et al., *Advances in Polymer Science*. Prog.Polym.Sci.)》 2006, 31, 487-531. Michael acceptor compounds having more than one Michael acceptor group are also well known. Examples include diacrylates such as ethylene glycol diacrylate and diethylene glycol diacrylate, dimethacrylates such as ethylene glycol methacrylate and diethylene glycol methacrylate, bismaleimides such as N,N'-(1,3-phenylene)dimaleimide and 1,1'-(methylenedi-4,1-phenylene)bismaleimide, and vinyl sulfones such as divinyl sulfone and 1,3-bis(vinylsulfonyl)-2-propanol. The Michael acceptor group that may be present in the polyene (a) according to the invention may, for example, have a structure of formula (1a) or formula (1b):

[0044] -CH2-CH2-S(O)2-R a -CH(-OH)-R a-S(O)2-CH=CH2 (1a)

[0045] -CH2-CH2-S(O)2-CH2-CH(-OH)-CH2-S(O)2-CH=CH2 (1b)

[0046] Each R a Selected independently from C 1-3 Alkyl and substituted C 1-3 Alkyl group, wherein one or more substituents are -OH.

[0047] In this article, "maleimide" refers to compounds containing a maleimide group:

[0048]

[0049] Bismaleimide is a compound having two maleimide groups, wherein the two maleimide groups are bonded by nitrogen atoms through connecting atoms or groups.

[0050] Therefore, Michael acceptor compounds can be used as polyenes (a) in the curable compositions according to the present invention. "Michael acceptor compound" refers to a compound comprising at least one terminal Michael acceptor group. In some instances, the Michael acceptor compound is a diethylene sulfone, and the Michael acceptor group is a vinylsulfonyl group, i.e.,

[0051] -S(O)2-CH=CH2.

[0052] For example, the Michael acceptor compound can be a bis(vinylsulfonyl)alkanol, and the Michael acceptor group can be, for example, 1-(vinylsulfonyl)-n-(vinylsulfonyl)alkanol or 1-(vinylsulfonyl)-3-(vinylsulfonyl)prop-2-ol.

[0053] The Michael acceptor group, which may be present in a compound suitable as a polyene (a) in a curable composition according to the invention, may also be maleimide and, in some instances, 1-(4-(4-(3-yl-2,5-dioxopyrrolidine-1-yl)benzyl)phenyl)-1H-pyrrole-2,5-dione.

[0054] Michael addition chemistry can be employed in various ways to provide curable compositions particularly suitable for use in aerospace sealant applications. For example, the curable compositions provided in this disclosure may include: (i) a thiol-terminated sulfur-containing prepolymer as a polythiol (b) and a Michael acceptor-terminated sulfur-containing prepolymer as a polyene (a); (ii) a mixture of a thiol-terminated sulfur-containing prepolymer and a low molecular weight polythiol as a polythiol (b) and a Michael acceptor-terminated sulfur-containing prepolymer as a polyene (a); (iii) a thiol-terminated sulfur-containing prepolymer as a polythiol (b) and a mixture of a Michael acceptor-terminated sulfur-containing prepolymer and a low molecular weight compound having at least two Michael acceptor groups as a polyene (a); or (iv) a mixture of a thiol-terminated sulfur-containing prepolymer and a low molecular weight polythiol as a polythiol (b) and a mixture of a Michael acceptor-terminated sulfur-containing prepolymer and a low molecular weight compound having at least two Michael acceptor groups as a polyene (a).

[0055] Michael receptor-terminated sulfur-containing prepolymers and thiol-terminated sulfur-containing prepolymers may be derived from polysulfides, polysulfides, sulfur-containing polyacetals, or any combination thereof.

[0056] The average molecular weight of low molecular weight polythiols and low molecular weight Michael receptor compounds can be less than about 400 Daltons or less than about 1,000 Daltons.

[0057] The sulfur-containing prepolymer with Michael acceptor end-capped structure may have at least two terminal unsaturated groups that are activated for Michael addition, such as activated unsaturated groups that act as Michael addition acceptors.

[0058] Michael acceptor-terminated sulfur-containing prepolymers that can be used as polyene(a) in curable compositions according to the invention typically comprise at least two terminal Michael acceptor groups. Therefore, suitable Michael acceptor-terminated sulfur-containing prepolymers can be, for example, bifunctional or can have a functionality greater than 2, such as 3, 4, 5, or 6. Michael acceptor-terminated sulfur-containing prepolymers can also comprise mixtures of Michael acceptor-terminated sulfur-containing prepolymers, which can have different functionalities, characterized by an average functionality of 2.05 to 6, 2.1 to 4, 2.1 to 3, 2.2 to 2.8, or 2.4 to 2.6. Therefore, suitable Michael acceptor-terminated sulfur-containing prepolymers can have at least two terminal Michael acceptor groups or can have two, three, four, five, or six terminal Michael acceptor groups. The sulfur-containing prepolymer with Michael acceptor end-capped structure may also include a combination of adducts, each of which may have a different number of terminal Michael acceptor groups, for example characterized by an average Michael acceptor functionality of 2.05 to 6, 2.1 to 4, 2.1 to 3, 2.2 to 2.8, or 2.4 to 2.6.

[0059] Suitable Michael acceptor-terminated sulfur-containing prepolymers include Michael acceptor-terminated polysulfides, Michael acceptor-terminated polysulfides, Michael acceptor-terminated sulfur-containing polyformaldehydes, and combinations thereof. For example, any of the polysulfides, polysulfides, and sulfur-containing polyformaldehydes suitable for use as thiol-terminated sulfur-containing prepolymers can also be used as the backbone of Michael acceptor-terminated sulfur-containing prepolymers.

[0060] For example, U.S. Patent Application Publication Nos. 2014 / 0378649, 2014 / 0378649 and 2015 / 0119549 disclose sulfur-containing prepolymers with Michael acceptor end-capsulation suitable for use in aerospace sealant applications.

[0061] As mentioned above, the Michael acceptor-terminated sulfur-containing prepolymer that can be used as a polyene (a) in the curable composition according to the present invention may include a Michael acceptor-terminated polysulfide.

[0062] Michael acceptor-terminated sulfur-containing prepolymers may, for example, include polysulfides comprising the following Michael acceptor-terminated components:

[0063] (a) The main chain of the structure including equation (2):

[0064] -R 1 -[-S-(CH2)2-O-[-R 2 -O-] m -(CH2)2-SR 1 ] n - (2)

[0065] Where (i) each R 1 Selected independently from C 2-10 n-alkyldiyl, C 3-6 Branched alkyl dimethyl, C 6-8 Cycloalkyldiyl, C 6-10 Alkyl, cycloalkanes, divalent heterocyclic groups, -[(-CHR) 3 -) p -X-] q -(CHR 3 ) r - groups, where each R 3 (ii) Each R is independently selected from hydrogen and methyl; 2 Selected independently from C 2-10 n-alkyldiyl, C 3-6 Branched alkyl dimethyl, C 6-8 Cycloalkyldiyl, C 6-14 Alkanes, cycloalkanes, divalent heterocyclic groups, and -[(-CH2-)] p -X-] q -(CH2) r-group; (iii) each X is independently selected from O, S and -NR 4 - group, where R 4 Selected from H and methyl; (iv) m is an integer ranging from 0 to 50; (v) n is an integer ranging from 1 to 60; (vi) p is an integer ranging from 2 to 6; (vii) q is an integer ranging from 1 to 5; and (viii) r is an integer ranging from 2 to 10; and

[0066] (b) At least two terminal Michael receptor groups, wherein each of the at least two terminal Michael receptor groups may be independently selected from any Michael receptor group described herein.

[0067] In the compound of formula (2), R 1 Specifically, it can be -[-(CHR) 3 ) p -X-] q -(CHR 3 ) r - where each X can be independently selected from -O- and -S-, where typically each X is -O- or each X is -S-.

[0068] More specifically, in the compound of formula (2), R 1 Specifically, it can be -[-(CH2)] p -X-] q -(CH2) r - where each X can be independently selected from -O- and -S-. In this paper, each X is typically -O- or each X is -S-.

[0069] Even more specifically, in the compound of formula (2), R 1 It can be -[(-CH2-)] p -X-] q -(CH2) r - where p can be 2, X can be 0, q is 2, r can be 2, and R 2 It can be ethylenedimethyl, m can be 2 and n can be 9.

[0070] The sulfur-containing prepolymer that can be used as the Michael acceptor-terminated polysulfide of formula (3a), the Michael acceptor-terminated polysulfide of formula (3b), or a combination thereof may be included, for example:

[0071] R 6 -SR 5 -[-S-(CH2) p -O-(R 7 -O) m -(CH2)2-SR 5-] n -SR 6

[0072] (3a)

[0073] {R 6 -SR 5 -[-S-(CH2) p -O-(R 7 -O) m -(CH2)2-SR 5 -] n -S--V'-} z B

[0074] (3b)

[0075] Where: each R 5 Selected independently from C 2-10 Alkyl, C 6-8 Cycloalkyldiyl, C 6-10 Alkane cycloalkane dimethyl, C 5-8 Heterocyclic alkyl dimethyl and -[(-CHR) 8 -) s -X-] q -(-CHR 8 -) r - where: s is an integer from 2 to 6; q is an integer from 1 to 5; r is an integer from 2 to 10; each R 8 Each X is independently selected from hydrogen and methyl; and each X is independently selected from -O-, -S-, -NH- and -N(-CH3)-; each R 7 Selected independently from C 1-10 Alkyl, C 6-8 Cycloalkyldiyl, C 6-14 Alkyl, cycloalkanes, and -[(-CHR) 8 -) s -X-] q -(-CHR 8 -) r - where s, q, r, R 8 And X is for R 5 As defined; m is an integer from 0 to 50; n is an integer from 1 to 60; p is an integer from 2 to 6; B represents the z-valent polyfunctional agent B(-V). z The core, where: z is an integer from 3 to 6; and each V is a group including a terminal group reactive with a thiol group; and each -V'- originates from the reaction of -V with a thiol; and each R 6 Independently, it is the portion that includes the terminal Michael receptor group.

[0076] In the prepolymer of formula (3a) and the prepolymer of formula (3b), R 5Specifically, it can be -[(-CH2-) s -X-] q -(CH2) r -, where s can be 2, X can be -O-, q can be 2, r can be 2, R 7 It can be ethylenedimethyl, m can be 2 and n can be 9.

[0077] In the prepolymer of formula (3a) and the prepolymer of formula (3b), R 5 For example, it can be selected from C 2-6 Alkyl and -[-(CHR) 8 ) s -X-] q -(CHR 8 ) r -

[0078] In the prepolymer of formula (3a) and the prepolymer of formula (3b), R 5 Specifically, it can be -[-(CHR) 8 ) s -X-] q -(CHR 8 ) r -, where X is -O- or X is -S-.

[0079] More specifically, in the prepolymer of formula (3a) and the prepolymer of formula (3b), R 5 It can be -[-(CHR) 8 ) s -X-] q -(CHR 8 ) r -, where s can be 2, r can be 2, q can be 1 and X can be -S-; or where s can be 2, q can be 2, r can be 2 and X can be -O-; or where s can be 2, r can be 2, q can be 1 and X can be -O-.

[0080] Furthermore, in the prepolymers of formula (3a) and (3b), where R 5 It can be -[-(CHR) 8 ) s -X-] q -(CHR 8 ) r -, each R 8 Or at least one R 8 It can be methyl.

[0081] In the prepolymers of formula (3a) and (3b), each R 5 They can be the same, or at least one R. 5 They can be different.

[0082] In the prepolymer of formula (3b), each -V may include a terminal alkenyl group.

[0083] In the adduct of formula (3a) and the adduct of formula (3b), each R 6 They can be independently selected from, for example, ketene, vinyl sulfone, and quinone. Each Michael acceptor group in the Michael acceptor group can be the same, or at least some of the Michael acceptor groups in the Michael acceptor group can be different from each other.

[0084] In the adduct of formula (3a) and the adduct of formula (3b), each R 6 It can also be a bis(sulfonyl)alkylol group independently.

[0085] In the adduct of formula (3a) and the adduct of formula (3b), each R 6 It can also be derived independently from bis(sulfonyl)alkanols and have a structure of formula (4a) or formula (4b):

[0086] -CH2-CH2-S(O)2-R 9 -CH(-OH)-R 9 -S(O)2-CH=CH2 (4a)

[0087] -CH2-CH2-S(O)2-CH2-CH(-OH)-CH2-S(O)2-CH=CH2 (4b)

[0088] Each R 9 Selected independently from C 1-3 Alkyl.

[0089] However, the Michael acceptor group that capsulates the sulfur-containing prepolymer of the polyene that can be used in the curable composition according to the invention is not specifically limited and can generally be any suitable Michael acceptor group.

[0090] In the prepolymers of formula (3a) and (3b), each R 6Examples of derivatives derived from bismaleimides include 1,1'-(methylenebis(4,1-phenylene)bis(1H-pyrrole-2,5-dione), ethylene bismaleimide, 1,6-bismaleimide hexane, 2,4-dimaleimide toluene, N,N'-1,3-phenylene bismaleimide; 1,4-bis(maleimide)butane trimethylene bismaleimide; p,p'-dimaleimide diphenylmethane; pentamethylene bismaleimide 1H-pyrrole-2,5-dione; 1,1'-(1,8-octanediyl)bis-,1H-pyrrole-2,5-dione, 1,1' -(1,7-heptanediyl)bis-,4,4'-disulfide bis(phenylmaleimide); methylene bis(N-carbamoylmaleimide), 1,9-bis(maleimide)nonane; 1,1'-decane-1,10-diylbis(1H-pyrrole-2,5-dione); O-phenylene dimaleimide, bis(N-maleimide methyl) ether; 1,5-bis(maleimide)-2-methyl-pentane; N,N'-1,4-phenylene dimaleimide; 1,1'-(2-methyl-1,3-phenylene)bis(1H-pyrrole-2,5-dione); Kerimid 601 resin; tetrakis(N-2-aminoethylmaleimide); 1-(2,5-dimethylphenyl)pyrrole-2,5-dione; SureCN331305; SureCN349749; or 1,1'-biphenyl-4,4'-dimethylbis(1H-pyrrole-2,5-dione).

[0091] Michael acceptor-terminated sulfur-containing prepolymers may include at least two terminal maleimide groups.

[0092] As indicated above, the Michael acceptor group may also include a bis(sulfonyl)alkanol group, such as 1-(vinylsulfonyl)-n-(vinylsulfonyl)alkanol or 1-(vinylsulfonyl)-3-(vinylsulfonyl)prop-2-ol. Each Michael acceptor group in the Michael acceptor-terminated sulfur-containing prepolymer may be identical, or at least some of the Michael acceptor groups may be different from each other.

[0093] "Bis(sulfonyl)alkanol" refers to a group that includes a part having the following general formula:

[0094] -S(O)2-R 10 -CH(-OH)-R 10 -S(O)2-

[0095] Each R 10 Selected independently from C 1-3 Alkyl and substituted C 1-3 Alkyl group, wherein one or more substituents are -OH. In some instances, the bis(sulfonyl)alkanol group has the following structure:

[0096] -CH2-CH2-S(O)2-R 10 -CH(-OH)-R 10 -S(O)2-CH2-CH2-

[0097] And in some cases, it has the following structure:

[0098] R 11 -S(O)2-R 10 -CH(-OH)-R 10 -S(O)2-R 11

[0099] Each R 11 It is the part with terminal reactive groups. Each R 11 It may include terminal groups that are reactive with the thiol group, such as alkenyl, epoxy, or Michael acceptor groups. In some cases, bis(sulfonyl)alkanols may be bis(vinylsulfonyl)alkanols that include a terminal alkenyl group. For example, a bis(sulfonyl)alkanol may be a bis(vinylsulfonyl)alkanol, wherein R 11 Including terminal alkenyl groups, such as compounds having the following formula:

[0100] CH2=CH-S(O)2-R 10 -CH(-OH)-R 10 -S(O)2-CH=CH2.

[0101] Di(vinylsulfonyl)alkanols may, for example, include 1,3-bis(vinylsulfonyl)-2-propanol. Di(sulfonyl)alkanols can be prepared by reacting a bis(vinylsulfonyl)alkanol with a compound having a terminal group (such as a thiol group or an epoxy group) reactive with the terminal alkenyl group of the bis(vinylsulfonyl)alkanol. In this case, the bis(sulfonyl)alkanol may have the following structure:

[0102] R 12 -CH2-CH2-S(O)2-R 10 -CH(-OH)-R 10 -S(O)2-CH2-CH2-R 12

[0103] Each R 12 It is the part derived from the reaction of the compound with the terminal alkenyl group of bis(vinylsulfonyl)alkanol.

[0104] The term "bis(sulfonyl)alkanol" can be alternatively represented by a monovalent or divalent bis(sulfonyl)alkanol. The monovalent bis(sulfonyl)alkanol can be a terminal bis(sulfonyl)alkanol, such as "1-(ethylenesulfonyl)-n-(vinylsulfonyl)alkanol". The terminal bis(sulfonyl)alkanol can be derived from a reaction of bis(sulfonyl)alkanol and can have the general structure -R. 13 -S(O)2-R 15 -CH(-OH)-R 15 -S(O)2-R 14 The end portion, where R 13 It is the part derived from the reaction of bis(sulfonyl)alkanols with compounds having groups that are reactive with bis(sulfonyl)alkanols; each R 15 Selected independently from C 1-3 Alkyl and substituted C 1-3 Alkyl group, wherein one or more substituents are -OH. R 14 It can be an alkylene group, such as -CH=CH2. In some instances, the terminal bis(sulfonyl)alkanol group is 1-(ethylenesulfonyl)-n-(vinylsulfonyl)alkanol, such as 1-(ethylenesulfonyl)-3-(vinylsulfonyl)prop-2-ol, i.e., -CH2-CH2-S(O)2-CH2-CH(-OH)-CH2-S(O)2-CH=CH2. The monovalent terminal bis(sulfonyl)alkanol group can, for example, have the structure -CH2-CH2-S(O)2-R 15 -CH(-OH)-R 15 -S(O)2-CH=CH2.

[0105] In some instances, the bis(sulfonyl)alkanol group can also be divalent, such as when the group is incorporated into the backbone of prepolymers such as polysulfides disclosed herein. The divalent bis(sulfonyl)alkanol group can have the following general structure: -R 13 -S(O)2-R 15 -CH(-OH)-R 15 -S(O)2-R 13 -;

[0106] or -CH2-CH2-S(O)2-R 15 -CH(-OH)-R 15 -S(O)2-CH2-CH2-;

[0107] or -R 13 -S(O)2-CH2-CH(-OH)-CH2-S(O)2-R 13 -;

[0108] or -CH2-CH2-S(O)2-CH2-CH(-OH)-CH2-S(O)2-CH2-CH2-,

[0109] Where R 13 and R 15 As defined above. Each R 13 It can be, for example, ethane-diyl and / or each R 15 It can be methane-diyl.

[0110] "Polymers, prepolymers or adducts containing bis(sulfonyl)alkanols" refer to polymers, prepolymers or adducts in which one or more divalent bis(sulfonyl)alkanol groups are incorporated into the main chain of the polymer, prepolymer or adduct.

[0111] Divalent bis(sulfonyl)alkanol groups can be incorporated into the prepolymer by reacting a polythiol monomer or a prepolymer of formula I with a bis(sulfonyl)alkanol of formula II, for example, in a suitable ratio:

[0112] R(-SH) w (I)

[0113] R 16 -S(O)2-R 17 -CH(-OH)-R 17 -S(O)2-R 16 (II)

[0114] Where R is the organic part, and each R 17 Selected independently from C 1-3 Alkyl and substituted C 1-3 Alkyl group, wherein one or more substituents are -OH; w is an integer of at least 2, and each R 16 This includes terminal groups reactive to thiols, such as alkenyl and epoxy groups, or groups comprising a saturated carbon atom with a leaving group highly suited for nucleophilic substitution, such as -Cl, -Br, -I, -OSO2CH3 (methanesulfonate), -OSO2-C6H4-CH3 (toluenesulfonate), etc. In some cases, the bis(sulfonyl)alkanol of formula II can be a bis(vinylsulfonyl)alkanol having the following formula:

[0115] CH2=CH-S(O)2-R 17 -CH(-OH)-R 17 -S(O)2-CH=CH2

[0116] Each R 17As defined above. Suitable bis(sulfonyl)alkanols can be exemplified, for example, by 1,3-bis(vinylsulfonyl)-2-propanol. Alternatively, the bis(sulfonyl)alkanol group can be incorporated into the prepolymer backbone by reacting a thiol-terminated bis(sulfonyl)alkanol of Formula III with a reactant of Formula IV in a suitable ratio:

[0117] HS-RS(O)2-R 17 -CH(-OH)-R 17 -S(O)2-R-SH (III)

[0118] R"-RR" (IV)

[0119] Each R is a binary part, each R 17 As defined herein, and each R" includes a terminal group that is reactive with a thiol group, such as an alkenyl group, an epoxy group, or a group consisting of a saturated carbon with a leaving group commonly used for nucleophilic substitution, for example, -Cl, -Br, -I, -OSO2CH3 (methanesulfonate), -OSO2-C6H4-CH3 (toluenesulfonate), etc.

[0120] By selecting appropriate ratios of reactants of Formulas I and II or Formulas III and IV, one or more bis(sulfonyl)alkanol groups can be incorporated into the prepolymer as a chain segment, as part of a terminal portion with a reactive group, or both. For example, bis(vinylsulfonyl)alkanols can be used to introduce one or more 1,n-bis(vinylsulfonyl)alkanol groups, one or more terminal 1-(vinylsulfonyl)-n-(vinylsulfonyl)alkanol groups, or both, into the main chain of the prepolymer.

[0121] It is desirable to react bis(vinylsulfonyl)-2-propanol with thiol-terminated monomers / polymers to incorporate 1,3-bis(vinylsulfonyl)-2-propanol into the polymer chain.

[0122] Bis(vinylsulfonyl)-2-propanol can also react with thiol-terminated monomers / polymers to provide 1-(vinylsulfonyl)-3-(vinylsulfonyl)-2-propanol terminal groups, wherein the terminal alkenyl group is a recognized Michael acceptor.

[0123] The moiety derived from the reaction of bis(sulfonyl)alkanols with a thiol group refers to the reaction product of the thiol group and a moiety containing a terminal group reactive with the thiol group. Examples of terminal groups reactive with the thiol group include epoxy, vinyl, and Michael acceptor groups. In some instances, the moiety derived from the reaction of bis(sulfonyl)alkanols with a thiol group has the following structures: -CH2-CH2-R-, -CH(-OH)-CH2-R-, -CH2-CH(-OH)-R-, or -CH2-CH2-SO2-R-, where R represents a covalent bond or an organic moiety bonded to a sulfonyl group.

[0124] The Michael acceptor-terminated sulfur-containing prepolymer that can be used as the polyene(a) in the curable composition according to the invention may, for example, comprise at least two terminal 1-(ethylenesulfonyl)-n-(vinylsulfonyl)alkanol groups, such as two terminal 1-(ethylenesulfonyl)-n-(vinylsulfonyl)alkanol groups, three, four, five, or six terminal 1-(ethylenesulfonyl)-n-(vinylsulfonyl)alkanol groups. The Michael acceptor-terminated sulfur-containing prepolymer may comprise a combination of adducts having different numbers of terminal 1-(ethylenesulfonyl)-n-(vinylsulfonyl)alkanol groups, characterized, for example, by an average 1-(ethylenesulfonyl)-n-(vinylsulfonyl)alkanol functionality of 2.05 to 6, 2.1 to 4, 2.1 to 3, 2.2 to 2.8, or 2.4 to 2.6.

[0125] Michael acceptor groups, which may be present in polyenes that can be used in curable compositions according to the invention, may also be derived from vinyl sulfones and have the structure of formula (5):

[0126] -CH2-C(R 18 )2-S(O)2-CR 18 =CH2 (5)

[0127] Each R 18 Independently selected from hydrogen and C 1-3 Alkyl groups. In the Michael acceptor group of formula (5), each R 18 Hydrogen can be used, for example. Michael acceptor-terminated bis(sulfonyl)alkanol polysulfides can be prepared, for example, by reacting a thiol-terminated bis(sulfonyl)alkanol polysulfide with a compound having a terminal Michael acceptor group and a group reactive with the thiol group (such as diethylene sulfone) in the presence of a phosphine catalyst. Michael acceptor / polysulfide chemistry and compounds are disclosed, for example, in U.S. Application Publication No. 2013 / 0345371.

[0128] The sulfur-containing prepolymer used as the Michael acceptor-terminated polyene in the curable composition according to the invention may include at least two terminal vinyl sulfonyl groups.

[0129] In some instances, the Michael acceptor-terminated sulfur-containing prepolymer may be terminated by at least two vinylsulfonyl groups or at least two terminal 1-(vinylsulfonyl)-n-(vinylsulfonyl)alkanol groups.

[0130] Compounds having a Michael acceptor group and a group reactive to the terminal group of sulfur-containing polymers can be compounds having the formula R-CH2-CH2-S(O)2-R 19 -CH(-OH)-R 19 -S(O)2-CH=CH2 bis(sulfonyl)alkanol, wherein R can be a portion having a terminal group reactive with the terminal group of a sulfur-containing polymer; and each R 19 Selected independently from C 1-3 Alkyl. Di(vinyl)alkanols can be bis(vinylsulfonyl)alkanols.

[0131] The sulfur-containing maleimide adducts provided in this disclosure may include at least two terminal maleimide groups. The sulfur-containing maleimide adducts may include mixtures of sulfur-containing maleimide adducts having different functionalities characterized by an average functionality of 2.05 to 6, 2.1 to 4, 2.1 to 3, 2.2 to 2.8, or 2.4 to 2.6. The sulfur-containing maleimide adducts may have at least two terminal maleimide groups, or may have two terminal 1-(4-(4-(3-yl-2,5-dioxopyrrolidine-1-yl)benzyl)phenyl)-1H-pyrrole-2,5-diketone groups, or may have more than two terminal groups, such as 3, 4, 5, or 6 terminal 1-(4-(4-(3-yl-2,5-dioxopyrrolidine-1-yl)benzyl)phenyl)-1H-pyrrole-2,5-diketone groups. Sulfur-containing maleimide adducts may include combinations of adducts having, for example, an average 1-(4-(4-(3-yl-2,5-dioxopyrrolidone-1-yl)benzyl)phenyl)-1H-pyrrole-2,5-diketone functionality of 2.05 to 6, 2.1 to 4, 2.1 to 3, 2.2 to 2.8, or 2.4 to 2.6.

[0132] The double bonds of maleimide can react with thiols at pH 6.5 to 7.5 and are more reactive than (meth)acrylates. At neutral pH, the reaction of maleimide with thiols is approximately 1,000 times faster than the reaction of maleimide with amines. Compositions prepared from maleimide resins exhibit excellent thermomechanical stability and flame retardancy.

[0133] Maleimide-terminated sulfur-containing prepolymers may include polysulfide maleimide prepolymers, characterized by having at least two terminal maleimide groups, such as polysulfides having at least two terminal 1-(4-(4-(3-yl-2,5-dioxopyrrolidine-1-yl)benzyl)phenyl)-1H-pyrrole-2,5-diketone groups.

[0134] The terminal Michael acceptor group may be selected from 1,3-bis(vinylsulfonyl)-2-propanol, 1,1'-(methylenedi-4,1-phenylene)bismaleimide, or a combination thereof.

[0135] Sulfur-containing maleimide adducts that can be used as polyene(a) in curable compositions according to the present invention may include polysulfide maleimide adducts comprising:

[0136] (a) The main chain of the structure including equation (6):

[0137] -R 20 -[-S-(CH2)2-O-[-R 21 -O-] m -(CH2)2-SR 20 ] n - (6)

[0138] Where (i) each R 20 Selected independently from C 2-10 n-alkyldiyl, C 3-6 Branched alkyl dimethyl, C 6-8 Cycloalkyldiyl, C 6-10 Alkyl, cycloalkanes, heterocyclic groups, -[(-CHR) 22 -) p -X-] q -(CHR 22 ) r - groups, where each R 22 (ii) Each R is independently selected from hydrogen and methyl; 21 Selected independently from C 2-10 n-alkyldiyl, C 3-6 Branched alkyl dimethyl, C 6-8 Cycloalkyldiyl, C 6-14 Alkanes, cycloalkanes, heterocyclic groups, and -[(-CH2-)] p -X-] q -(CH2) r -group; (iii) each X is independently selected from O, S and -NR 23 - group, where R 23(iv) m is an integer ranging from 0 to 50; (v) n is an integer ranging from 1 to 60; (vi) p is an integer ranging from 2 to 6; (vii) q is an integer ranging from 1 to 5; and (viii) r is an integer ranging from 2 to 10; and (b) at least two terminal maleimide groups, which may, for example, be independently selected from any terminal maleimide group described herein.

[0139] In the adduct of equation (6), R 20 For example, it could be -[-(CHR) 22 ) p -X-] q -(CHR 22 ) r - where each X is independently selected from -O- and -S-.

[0140] More specifically, in the adduct of formula (6), R 20 It can be -[-(CH2)] p -X-] q -(CH2) r - where each X is independently selected from -O- and -S-, where typically each X is -O- or each X is -S-.

[0141] Even more specifically, in the adduct of formula (6), R 20 It can be -[(-CH2-)] p -X-] q -(CH2) r - where p can be 2, X can be 0, q can be 2, r can be 2, and R 21 It can be ethylenedimethyl, m can be 2 and n can be 9.

[0142] The terminal maleimide group can have the structure of formula (7):

[0143]

[0144] The terminal bismaleimide moiety refers to the portion having a terminal maleimide group. The terminal maleimide group can be derived from bismaleimides, such as compounds having the structure of formula (8a):

[0145]

[0146] Where R 10 It is a divalent organic moiety, and the terminal group can have the structure of formula (8b):

[0147]

[0148] And in this document it is referred to as 1-(4-(4-(3-yl-2,5-dioxopyrrolidine-1-yl)benzyl)phenyl)-1H-pyrrole-2,5-dione. The terminal maleimide group can be derived from 1,1'-(methylenedi-4,1-phenylene)bismaleimide of formula (9a), also referred to as 1,1'-(methylenebis(4,1-phenylene)bis(1H-pyrrole-2,5-dione), and the terminal group can have the structure of formula (9b):

[0149]

[0150] The maleimide group may include 1-(4-(4-(3-yl-2,5-dioxopyrrolidone-1-yl)benzyl)phenyl)-1H-pyrrole-2,5-dione. Each of the terminal maleimide groups may be the same, or at least some of the terminal maleimide groups may be different from each other.

[0151] Other examples of compounds having two or more maleimide groups include: ethylene bismaleimide; 1,6-bismaleimide hexane; 2,4-dimaleimide toluene, N,N'-1,3-phenylene bismaleimide; 1,4-bis(maleimide)butane trimethylene bismaleimide; p,p'-dimaleimide diphenylmethane; pentamethylene bismaleimide 1H-pyrrole-2,5-dione; 1,1'-(1,8-octanediyl)bis-,1H-pyrrole-2,5-dione, 1,1'-(1,7-hept ...,1H-heptanediyl)bis-,1H-pyrrole-2,5-dione, 1,1'-,1H-heptanediyl)bis-,1H-pyrrole-2,5-dione, 1,1'-,1H-heptanediyl)bis-,1H-pyrrole-2,5-dione, 1,1'-,1H-heptanediyl)bis-,1H-pyrrole-2,5-dione, 1,1'-,1H-heptanediyl)bis- -,4,4'-Disulfide bis(phenylmaleimide); methylene bis(N-carbamoylmaleimide), 1,9-bis(maleimide)nonane; 1,1'-decane-1,10-dimethylbis(1H-pyrrole-2,5-dione); O-phenylene dimaleimide, bis(N-maleimide methyl) ether; 1,5-bis(maleimide)-2-methyl-pentane; N,N'-1,4-phenylene dimaleimide; 1,1'-(2-methyl-1,3-phenylene)bis(1H-pyrrole-2,5-dione); Kerimid 601 resin; tetrakis(N-2-aminoethylmaleimide); 1-(2,5-dimethylphenyl)pyrrole-2,5-dione; SureCN331305, SureCN349749; or 1,1'-biphenyl-4,4'-dimethylbis(1H-pyrrole-2,5-dione).

[0152] To prepare Michael acceptor-terminated sulfur-containing prepolymers, sulfur-containing prepolymers such as those disclosed herein can be reacted with compounds having Michael acceptor groups and groups reactive with the terminal groups of the sulfur-containing prepolymers.

[0153] The Michael acceptor group can be selected, for example, from ketene, vinyl sulfone, maleimide, and quinone. In compounds where the Michael acceptor group is derived from divinyl sulfone, the sulfur-containing prepolymer can be thiol-terminated, such as thiol-terminated polysulfides, thiol-terminated polysulfides, or combinations thereof.

[0154] The polyene (a) is typically present in the curable composition of the present invention in an amount of at least 10% by weight but less than 90% by weight, based on the total weight of components (a) and (b) in the curable composition. For example, the polyene (a) may be present in the curable composition in an amount of at least 10% by weight, typically at least 30% by weight, at least 50% by weight, or even at least 60% by weight, based on the total weight of components (a) and (b) in the curable composition, as shown in the examples below. Furthermore, the polyene (a) may be present in the curable composition in an amount of up to 75% by weight, typically up to 60% by weight, based on the total weight of components (a) and (b) in the curable composition.

[0155] The curable compositions of the present invention further comprise (b) a polythiol. As used herein, the term "polythiol" refers to a compound containing two or more thiol functional groups (-SH). Many polythiools (b) are suitable for use in the curable compositions according to the present invention and can vary widely. Such polythiools may include those known in the art. Examples of suitable polythiools may include, but are not limited to, polythiools having at least two thiol groups, including monomeric compounds, oligomers, prepolymers, and polymers. Polythiools may have ether bonds (-O-), thioether bonds (-S-), and combinations thereof, wherein the thioether bonds include polysulfide bonds (-S-). x -), where x is at least 2, such as 2 to 4.

[0156] The polythiol (b) used in this invention comprises a material of the following formula:

[0157] R 24 -(SH) n

[0158] Where R 24 The organic moiety is n, which is at least 2, typically an integer from 2 to 6. This polythiol can, for example, comprise the reaction products of thiol-functionalized organic acids and polyols. Therefore, the organic moiety R... 24 It may contain ester groups and / or be derived from polyols.

[0159] Therefore, examples of suitable polythiols that can be used in the curable compositions according to the invention can be, for example, containing HS-R. 25 -COOH-containing thioglycolic acids and R-structure 26 -(OH) n esters of polyhydroxy compounds, wherein R 25It is the organic part, in which R 26 The component is an organic moiety and n is at least 2, typically 2 to 6. The thiol-containing component and the polyhydroxy component can be reacted under suitable conditions to yield a polythiol having the following general structure:

[0160] R 26 -(OC(=O)-R 25 -SH) n

[0161] Examples of such esters containing thioglycolic acids include esters of thioglycolic acid (HS-CH2COOH), α-mercaptopropionic acid (HS-CH(CH3)-COOH), or β-mercaptopropionic acid (HS-CH2CH2COOH) with polyhydroxy compounds such as ethylene glycol, triol, tetraol, pentane, hexanol, and mixtures thereof. Specific examples of suitable polythiols include, for example, ethylene glycol bis(thioglycolate), ethylene glycol bis(β-mercaptopropionic acid), trimethylolpropane tri(thioglycolate), trimethylolpropane tri(β-mercaptopropionic acid), pentaerythritol tetra(thioglycolate), and pentaerythritol tetra(β-mercaptopropionic acid), and mixtures thereof.

[0162] Suitable polythiols (b) for use in curable compositions according to the invention, which are particularly useful in the aerospace industry, may comprise thiol-terminated sulfur-containing prepolymers, such as thiol-terminated polysulfide prepolymers, thiol-terminated polysulfide prepolymers, thiol-terminated sulfur-containing polyacetal prepolymers, or combinations of any of the foregoing. The thiol-terminated sulfur-containing prepolymers may also comprise mixtures of different polysulfides and / or polysulfides, and the polysulfides and / or polysulfides may have the same or different thiol functionalities. The thiol-terminated sulfur-containing prepolymers may have an average thiol functionality of 2 to 6, 2 to 4, 2 to 3, or 2.05 to 2.8. For example, thiol-terminated sulfur-containing prepolymers may comprise difunctional thiol-terminated sulfur-containing polymers, trifunctional thiol-terminated sulfur-containing polymers, or combinations thereof.

[0163] Examples of thiol-terminated polysulfide prepolymers suitable for use in the curable compositions provided in this disclosure are disclosed, for example, in U.S. Patent No. 6,172,179.

[0164] The sulfur-containing prepolymer suitable for thiol-terminated polythiol (b) in the curable composition according to the invention may, for example, include a main chain containing the structure of formula (10):

[0165] -R 27 -[-S-(CH2)2-O-[-R 28 -O-] m -(CH2)2-SR 27 ] n - (10)

[0166] in:

[0167] (i) Each R 27 Selected independently from C 2-10 n-alkyldiyl, C 3-6 Branched alkyl dimethyl, C 6-8 Cycloalkyldiyl, C 6-10 Alkyl, cycloalkanes, divalent heterocyclic groups and -[(-CHR) 29 -) p -X-] q -(CHR 29 ) r - groups, where each R 29 Selected from hydrogen and methyl;

[0168] (ii) Each R 28 Selected independently from C 2-10 n-alkyldiyl, C 3-6 Branched alkyl dimethyl, C 6-8 Cycloalkyldiyl, C 6-14 Alkanes, cycloalkanes, divalent heterocyclic groups, and -[(-CH2-)] p -X-] q -(CH2) r -group;

[0169] (iii) Each X is independently selected from O, S, -NH- and -N(-CH3)-;

[0170] (iv) m is an integer ranging from 0 to 50;

[0171] (v)n is an integer ranging from 1 to 60;

[0172] (vi)p is an integer in the range of 2 to 6;

[0173] (vii)q is an integer ranging from 1 to 5; and

[0174] (viii)r is an integer ranging from 2 to 10.

[0175] The thiol-terminated sulfur-containing prepolymer suitable as the polythiol (b) in the curable composition according to the invention may, for example, include the thiol-terminated polysulfide prepolymer of formula (11a), the thiol-terminated polysulfide prepolymer of formula (11b), or a combination thereof:

[0176] HS-R 30 -[-S-(CH2) p -O-(R 31 -O) m -(CH2)2-SR 30 -] n -SH

[0177] (11a)

[0178] {HS-R 30 -[-S-(CH2) p -O-(R 31 -O) m -(CH2)2-SR 30 -] n -S-V'-} z B

[0179] (11b)

[0180] in:

[0181] Each R 30 Selected independently from C 2-10 Alkyl, C 6-8 Cycloalkyldiyl, C 6-14 Alkane cycloalkane dimethyl, C 5-8 Heterocyclic alkyl dimethyl and -[(-CHR) 32 -) s -X-] q -(-CHR 32 -) r -,in:

[0182] s is an integer from 2 to 6; q is an integer from 1 to 5; r is an integer from 2 to 10; each R 32 Each X is independently selected from hydrogen and methyl; and each X is independently selected from -O-, -S-, -NH- and -N(-CH3)-; each R 31 Selected independently from C 1-10 Alkyl, C 6-8 Cycloalkyldiyl, C 6-14 Alkyl, cycloalkanes, and -[(-CHR) 32 -) s -X-] q -(-CHR 32 -) r - where s, q, r, R 32 And X is for R 30 As defined; m is an integer from 0 to 50; n is an integer from 1 to 60; p is an integer from 2 to 6; B represents a vinyl-terminated z-valent polyfunctional agent B(-V). z The core of the formula is: z is an integer from 3 to 6; and each V is a group including a terminal vinyl group; and each -V'- originates from the reaction of -V with a thiol.

[0183] In the prepolymers of formula (11a) and (11b), R 30 For example, it could be -[(-CH2-) s -X-]q -(CH2) r -, where s can be 2, X can be -O-, q can be 2, r can be 2, R 2 It can be ethylenedimethyl, m can be 2 and n can be 9.

[0184] In the prepolymers of formula (11a) and (11b), R 30 Can be selected from C 2-6 Alkyl and -[-(CHR) 32 ) s -X-] q -(CHR 32 ) r -

[0185] In the prepolymers of formula (11a) and (11b), R 30 Specifically, it can be -[-(CHR) 32 ) s -X-] q -(CHR 32 ) r -, where X is -O- or X is -S-.

[0186] In the specific prepolymers of formula (11a) and formula (11b), R 30 It can be -[-(CHR) 32 ) s -X-] q -(CHR 32 ) r -, where s is 2, r is 2, q is 1 and X is -S-; or s is 2, q is 2, r is 2 and X is -O-; or s is 2, r is 2, q is 1 and X is -O-.

[0187] Furthermore, in the prepolymers of formula (11a) and (11b), R 30 It can be -[-(CHR) 32 ) s -X-] q -(CHR 32 ) r -, where each R 32 It is hydrogen or at least one R 32 It is a methyl group.

[0188] In the prepolymers of formula (11a) and (11b), each R 30 They can usually be the same, or at least one R. 30 They can be different.

[0189] Various methods can be used to prepare thiol-terminated polysulfide prepolymers that can be used as polythiols in curable compositions according to the present invention. For example, examples of suitable thiol-terminated polysulfide prepolymers and methods for their production are described in U.S. Patent No. 6,172,179. The thiol-terminated polysulfide prepolymers can be difunctional (e.g., linear prepolymers having two thiol terminal groups) or polyfunctional (e.g., branched prepolymers having three or more terminal thiol groups). The thiol-terminated polysulfide prepolymers can also comprise combinations of difunctional thiol-terminated polysulfide prepolymers and polyfunctional thiol-terminated polysulfide prepolymers. Suitable thiol-terminated polysulfide prepolymers can, for example, be prepared by… The P3.1E was commercially acquired from PRC-DeSoto International Inc., Sylmar, CA.

[0190] Suitable difunctional thiol-terminated polysulfide prepolymers can be produced by reacting a diethylene ether or a mixture of diethylene ethers with an excess of a dithiol or a mixture of dithiols. For example, dithiols suitable for use in the preparation of thiol-terminated polysulfide prepolymers include those having the structure of formula (12), other dithiols disclosed herein, or any combination of dithiols disclosed herein.

[0191] The dithiols that can be used to prepare the thiol-terminated polysulfides provided in this disclosure can, for example, have the structure of formula (12):

[0192] HS-R 33 -SH (12)

[0193] Where: R 33 Selected from C 2-6 Alkyl, C 6-8 Cycloalkyldiyl, C 6-10 Alkane cycloalkane dimethyl, C 5-8 Heterocyclic alkyl dimethyl and -[-(CHR) 34 ) p -X-] q -(CHR 34 ) r -; where: each R 34 Each X is independently selected from hydrogen and methyl; each X is independently selected from -O-, -S- and -NR-, where R is selected from hydrogen and methyl; p is an integer from 2 to 6; q is an integer from 1 to 5; and r is an integer from 2 to 10.

[0194] In the dithiol of formula (12), R 33 Specifically, it can be -[-(CHR) 34 ) p -X-] q-(CHR 34 ) r -

[0195] In the dithiol of formula (12), X can specifically be -O- or -S-, and therefore, -[-(CHR) in formula (12) 34 ) p -X-] q -(CHR 34 ) r -can be-[(-CHR) 34 -) p -O-] q -(CHR 34 ) r -or-[(-CHR 34 -) p -S-] q -(CHR 34 ) r -. In the structure -[(-CHR 34 ) p -X-] q -(CHR 34 ) r In the - part, p and r can be the same, such as p and r can be two.

[0196] In the dithiol of formula (12), R 33 For example, it can be C. 2-6 Alkyl or -[(-CHR) 34 ) p -X-] q -(CHR 34 ) r -

[0197] In the dithiol of formula (12), where R 33 -[(-CHR) 34 ) p -X-] q -(CHR 34 ) r Specifically, X can be -O- or X can be -S-.

[0198] In the dithiol of formula (12), R 33 For example, it could be -[-(CHR) 34 ) p -X-] q -(CHR 34 ) r-, where 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 -O-; or p can be 2, r can be 2, q can be 1 and X can be -O-.

[0199] In the dithiol of formula (12), R 33 For example, it could be -[(-CHR) 34 ) p -X-] q -(CHR 34 ) r -, where each R 34 It is hydrogen or at least one R 34 It is a methyl group.

[0200] Suitable, non-limiting examples of dithiols that can be used to prepare thiol-terminated polysulfide prepolymers include 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,3-pentanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,3-dimercapto-3-methylbutane, dipentenedithiol, ethylcyclohexyldithiol (ECHDT), dimercaptodiethyl sulfide, methyl-substituted dimercaptodiethyl sulfide, dimethyl-substituted dimercaptodiethyl sulfide, dimercaptodioxane, 1,5-dimercapto-3-oxapentane, and combinations thereof. Polythiols may have a composition selected from lower (e.g., C...) 1-6 )alkyl, lower (e.g., C 1-6 One or more alkoxy and hydroxyl side groups. Suitable alkyl side groups contain, for example, C10. 1-6 straight-chain alkyl, C 3-6 Branched alkyl, cyclopentyl, and cyclohexyl groups.

[0201] Therefore, dithiols containing heteroatoms in both the carbon backbone and side alkyl groups such as methyl groups can also be used. Such compounds include, for example, methyl-substituted DMDS such as HS-CH2CH(CH3)-S-CH2CH2-SH, HS-CH(CH3)CH2-S-CH2CH2-SH and dimethyl-substituted DMDS such as HS-CH2CH(CH3)-S-CH(CH3)CH2-SH and HS-CH(CH3)CH2-S-CH2CH(CH3)-SH.

[0202] Suitable diethylene ethers for use in the preparation of polysulfide prepolymers include, for example, diethylene ethers of formula (13):

[0203] CH2=CH-O-(-R 35 -O-) m-CH=CH2 (13)

[0204] In equation (13), R 35 It can be C 2-6 n-alkyldiyl, C 3-6 Branched alkyl dimethyl, C 6-8 Cycloalkyldiyl, C 6-10 Alkyl cycloalkane dimethyl or -[(-CH2-)] p -O-] q -(-CH2-) r - where p is an integer in the range of 2 to 6, q is an integer in the range of 1 to 5, and r is an integer in the range of 2 to 10.

[0205] Suitable diethylene ethers comprise, for example, diethylene ethers having at least one oxoalkyl diol, such as 1 to 4 oxoalkyl diols, i.e., compounds in formula (13) where m is an integer ranging from 1 to 4. In diethylene ethers of formula (13), m can, for example, be an integer ranging from 2 to 4. Commercially available mixtures of diethylene ethers can also be used, characterized by a non-integer mean number of oxoalkyl diol units per molecule. Therefore, m in formula (13) can also be a rational value ranging from 0 to 10.0, such as 1.0 to 10.0, 1.0 to 4.0, or 2.0 to 4.0.

[0206] Suitable, non-limiting examples of diethylene ethers include diethylene ethers, ethylene glycol diethylene ether (EG-DVE), butanediol diethylene ether (BD-DVE), hexanediol diethylene ether (HD-DVE), diethylene glycol diethylene ether (DEG-DVE), triethylene glycol diethylene ether, tetraethylene glycol diethylene ether, cyclohexanediethanol diethylene ether, polytetrahydrofuranyl diethylene ether, and combinations of two or more such diethylene ether monomers. The diethylene ether may optionally have one or more side groups selected from alkyl, hydroxyl, alkoxy, and amino groups.

[0207] In the diethylene ether of formula (13), R 35 For example, it can be C. 3-6 Branched alkyl diols, which can be prepared by reacting a polyhydroxy compound with acetylene. Examples of this type of diethylene ether include compounds in which R in formula (13) 35 It is a methanal group substituted with an alkyl group, such as -CH(CH3)- (for example, Blends, such as E-200 diethylene ether (BASF Corp., Parsippany, NJ, where R in formula (13) is...) 35Ethylene glycol (where m is 3.8) or alkyl-substituted ethylene glycol (e.g., -CH2CH(CH3)-, such as DPE polymer blends containing DPE-2 and DPE-3; International Specialty Products, Wayne, NJ).

[0208] Other useful diethylene ethers include R in formula (13). 35 Diethylene ethers that are polytetrahydrofuranyl (polyTHF) or polyoxyalkylene dimethyl, such as those diethylene ethers that have an average of about 3 monomer units.

[0209] Two or more types of dithiols and / or two or more types of divinyl ether monomers of formula (13) can be used in the preparation of thiol-terminated polysulfide prepolymers. Thus, for example, two types of dithiols and one type of divinyl ether monomer of formula (13), one type of dithiols and two types of divinyl ether monomers of formula (12), two types of dithiols and two types of divinyl ether monomers of formula (13), and more than two types of dithiols and two types of divinyl ethers of formula (12) can be used to produce a variety of thiol-terminated polysulfide prepolymers.

[0210] Diethylene ether monomer may comprise 20 mol% to less than 50 mol% or 30 mol% to less than 50 mol% of the reactants used to prepare thiol-terminated polysulfide prepolymers.

[0211] The relative amounts of dithiol and divinyl ether can be selected to produce polysulfide prepolymers with terminal thiol groups. Thus, a dithiol of formula (12) or a mixture of at least two different dithiools of formula (12) can react with a divinyl ether of formula (13) or a mixture of at least two different divinyl ethers of formula (13) in relative amounts such that the molar ratio of thiol groups to vinyl groups is greater than 1:1, such as from 1.1 to 2.0:1.0.

[0212] The thiol-terminated polysulfide prepolymers provided in this disclosure can be prepared by combining at least one dithiol of formula (12) and at least one divinyl ether of formula (13), then adding a suitable catalyst, and reacting at a temperature of 30°C to 120°C, such as 70°C to 90°C, for a duration of 2 hours to 24 hours, such as 2 hours to 6 hours.

[0213] Thiol-terminated polysulfide prepolymers may also include highly functionalized polysulfides, i.e., those having an average thiol functionality greater than 2.0. Suitable highly functionalized thiol-terminated polysulfide prepolymers include, for example, those having the structure of formula (14):

[0214] B(-A-SH) z (14)

[0215] Wherein (i)A includes a divalent linker; (ii)B represents a z-valent residue of a multifunctional agent; and (iii)Z may have a mean greater than 2.0, such as a mean between 2 and 3, a mean between 2 and 4, a mean between 3 and 6, or may be an integer from 3 to 6.

[0216] Suitable polyfunctionalizing agents for use in the preparation of such highly functionalized thiol-terminated prepolymers include trifunctionalizing agents in which z is 3. Suitable trifunctionalizing agents include, for example, triallyl cyanurate (TAC), 1,2,3-propanetrithiol, isocyanurate-containing trithiols, and combinations thereof, as disclosed in U.S. Application Publication No. 2010 / 0010133. Other useful polyfunctionalizing agents include: triethylene ether monomers, such as trimethylolpropane triethylene ether; tetrafunctional ether monomers, such as pentaerythritol tetraethylene ether; and polythiols described in the following U.S. patents: U.S. Patent Nos. 4,366,307; 4,609,762; and 5,225,472. Mixtures of polyfunctionalizing agents may also be used.

[0217] Therefore, the thiol-terminated polysulfide prepolymers provided in this disclosure are characterized by a wide range of average thiol functionality. For example, a combination of difunctional and trifunctional prepolymers can provide an average thiol functionality of 2.05 to 3.0, such as 2.1 to 2.6. An even wider range of average thiol functionality can be achieved by using tetrafunctional or higher-functionalized multifunctional agents. Functionality may also be affected by factors such as stoichiometry.

[0218] Thiol-terminated polysulfide prepolymers with a functionality greater than 2.0 can be prepared in a manner similar to that described in U.S. Application Publication No. 2010 / 0010133. For example, thiol-terminated polysulfide prepolymers can be prepared by combining (i) one or more dithiols described herein with (ii) one or more divinyl ethers described herein and (iii) one or more multifunctionalizing agents, as mentioned above. The mixture can then be optionally reacted in the presence of a suitable catalyst to provide thiol-terminated polysulfide prepolymers with a functionality greater than 2.0.

[0219] The thiol-terminated polysulfide prepolymers provided in this disclosure represent thiol-terminated polysulfide prepolymers having a molecular weight distribution. For example, useful thiol-terminated polysulfide prepolymers may be characterized by a number average molecular weight in the range of 500 Daltons to 20,000 Daltons, 2,000 Daltons to 5,000 Daltons, or 3,000 Daltons to 4,000 Daltons. Useful thiol-terminated polysulfide prepolymers may exhibit a polydispersity (Mi) in the range of, for example, 1 to 20 or 1 to 5. w / M n (Weight-average molecular weight / number-average molecular weight). The molecular weight distribution of thiol-terminated polysulfide prepolymers can be characterized by gel permeation chromatography.

[0220] As mentioned above, thiol-terminated polysulfides can also be used as polythiols (b) in the curable compositions according to the present invention. In this document, "polysulfide" can refer to a compound containing one or more sulfide bonds, i.e., -S, at the side positions in the polymer backbone and / or prepolymer chain. x Prepolymers with 2 to 4 sulfur-sulfur bonds. Polysulfide prepolymers can have two or more sulfur-sulfur bonds. Suitable thiol-terminated polysulfides are available, for example, from Akzo Nobel and Toray Fine Chemicals under the names Thiokol-LP and... Acquired through commercial purchase. The products are available in a wide range of molecular weights, for example, less than 1,100 to more than 8,000, where molecular weight is the average molecular weight in grams per mole. In some cases, the number-average molecular weight of the polysulfides is from 1,000 Daltons to 4,000 Daltons. Examples of suitable thiol-terminated polysulfides are disclosed in U.S. Patent No. 4,623,711.

[0221] Thiol-terminated sulfur-containing polyacetal prepolymers of polythiols (b) in curable compositions according to the invention, which can be used as sealants for aerospace applications, are disclosed, for example, in U.S. Application Publication No. 2012 / 0234205 and U.S. Application Publication No. 2012 / 0238707.

[0222] Thiol-terminated sulfur-containing prepolymers that can be used as polythiols in curable compositions according to the present invention may include thiols-terminated sulfur-containing prepolymers containing metal ligands, wherein the metal ligands are incorporated into the backbone of the prepolymer. Sulfur-containing prepolymers containing metal ligands are disclosed in U.S. Patent Application Publications Nos. 2014 / 0275474, 2014 / 0378650, and 2014 / 0378649.

[0223] Polythiols (b) are typically present in the curable compositions of the present invention in an amount greater than 10% by weight to 90% by weight, based on the total weight of components (a) and (b) in the curable composition. For example, polythiols (b) may be present in the curable compositions in an amount of at least 10% by weight, typically at least 30% by weight, at least 50% by weight, or even at least 60% by weight, based on the total weight of components (a) and (b) in the curable composition, as shown in the examples below. Furthermore, polythiols (b) may be present in the curable compositions in an amount of up to 75% by weight, typically up to 60% by weight, based on the total weight of components (a) and (b) in the curable composition. Typically, the equivalence ratio of the thiol functional group in the polythiol (b) to the olefinic unsaturated group in the polyene (a) is 0.1 to 10:1, such as 0.4 to 1.6:1.

[0224] The curable compositions of the present invention further comprise (c) any of the catalytic compositions described herein. The metal compound (i) of the catalytic composition is typically present in the curable compositions according to the invention in an amount of 1 to 1000 ppm metal, such as 5 ppm to 175 ppm or 15 ppm to 75 ppm metal, typically 25 ppm metal, based on the total weight of components (a) and (b) in the curable compositions according to the invention. The compound (ii) is typically present in the curable compositions according to the invention in an amount of 0.001 wt% to 10 wt%, such as 0.01 wt% to 5 wt%, based on the total weight of components (a) and (b) in the curable compositions.

[0225] When preparing the curable composition according to the invention, both components of the catalytic composition (c) may be added as individual packages to one or more components of the remaining components of the curable composition (i.e., added to (a) and / or (b)). Alternatively, one or more components of each component of the catalytic composition (c) may be added as separate packages to one or more components of the curable composition.

[0226] Optional ingredients such as plasticizers, antioxidants, thixotropic agents, reactive diluents, hindered amine light stabilizers, ultraviolet absorbers, and stabilizers can be formulated into the curable compositions of the present invention. These ingredients may be present in amounts of up to 30% by weight, often from 0.1% to 5% by weight (on an individual basis), based on the total weight of components (a) and (b) in the curable composition.

[0227] The curable compositions of the present invention often contain other optional ingredients, such as colorants. Examples of suitable pigments and / or pigment compositions include crude carbazole dioxazine pigments, azo, monoazo, diazo, naphthol AS, salt (lake), benzimidazolone, condensates, isoindolinone, isoindolin and polycyclic phthalocyanine, quinacridone, perylene, violet ketone, diketopyrrolopyrrole, thioindigo, anthraquinone, indigoanthraquinone, anthraquinone pyrimidine, flavinthrone, pinanthraquinone, anthraquinone, dioxazine, triarylcarbium, quinophthalone pigments, diketopyrrolopyrrole red (“DPPBO Red”), carbon black and mixtures thereof. The terms “pigment” and “colored filler” may be used interchangeably.

[0228] Example dyes include solvent- and / or water-based dyes, such as acid dyes, azo dyes, basic dyes, direct dyes, disperse dyes, reactive dyes, solvent dyes, sulfur dyes, mordant dyes, for example, bismuth vanadate, anthraquinone, perylene, aluminum, quinacridone, thiazole, thiazide, azo, indigo derivatives, nitro, nitroso, oxazine, phthalocyanine, quinoline, symmetrical diphenylethylene, and triphenylmethane.

[0229] When present, the pigment is typically used in the curable composition according to the invention in an amount of up to 80% by weight, such as from 1% to 80% by weight, based on the total solid weight of the composition.

[0230] The curable compositions of the present invention typically contain a diluent to dissolve and / or disperse the various components of the composition. Examples of suitable diluents include, but are not limited to, organic materials, including aromatic materials such as toluene and xylene, esters such as butyl acetate and amyl acetate, ethers such as dialkyl ethers of ethylene and propylene glycol, and ketones such as methyl ethyl ketone and methyl pentyl ketone. Other suitable diluents include water and water-miscible solvents such as alcohols and ethers.

[0231] In some embodiments of the invention, the curable compositions of the invention are substantially free of vanadium compounds, free radical polymerization initiators such as peroxides and other free radical polymerization initiators known in the field of addition polymerization, as well as reactive compounds including acid functional groups, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polybasic acids.

[0232] The curable composition according to the invention can be formulated to have a solid content of 1% to 100% by weight, such as 20% to 90% by weight or 20% to 80% by weight, based on the total weight of the composition.

[0233] The components of the composition are typically mixed together under low-shear mixing to form a curable composition. When pigments are present, the pigments are typically milled in one of the resin components of the composition, such as a polyene (a) or a polythiol (b), under high-shear mixing to form a pigment paste, which is then incorporated into the composition under low-shear mixing.

[0234] The curable composition can be used as a sealant or a protective or decorative coating composition and can be used as a primer or topcoat, including paints and varnishes. The composition can cure at low temperatures, such as ambient temperature, from -10°C to 80°C, or can withstand higher temperatures to achieve curing, but higher temperatures are generally not required. The composition has specific uses in the original manufacturing or refurbishment of automobiles and trucks. Other uses of the composition may include, but are not limited to, various transport and protective coatings.

[0235] The curable compositions of this invention can be applied to any substrate of various types, such as metal, glass, wood, and / or polymeric substrates, and can be applied by conventional methods including, but not limited to, brushing, dipping, flow coating, and spraying. The substrate can be bare, pretreated, or coated with a primer and / or sealant. The curable compositions are most commonly applied to the substrate by spraying. Common spraying techniques and equipment used for air spraying, airless spraying, and electrostatic spraying using manual and / or automated methods can be used. Suitable substrates include metallic substrates such as ferrous metals, zinc, copper, magnesium, aluminum, aluminum alloys, and other metallic and alloy substrates, such as those commonly used in the manufacture of automobiles and other vehicle bodies. Ferrous metal substrates can include iron, steel, and their alloys. Non-limiting examples of useful steel materials include cold-rolled steel, galvanized (zinc-coated) steel, electro-galvanized steel, stainless steel, acid-etched steel, zinc-iron alloys such as Galvaneal, and combinations thereof. Combinations or composites of ferrous and non-ferrous metals can also be used.

[0236] The curable compositions of the present invention can also be applied to elastomeric substrates, plastic substrates, or composite substrates, such as those found in motor vehicles. “Plastic” means any thermoplastic or thermosetting synthetic nonconductive material, including thermoplastic olefins such as polyethylene and polypropylene, thermoplastic urethanes, polycarbonates, thermosetting sheet molding compounds, reaction injection molding compounds, acrylonitrile-based materials, nylon, etc. “Composite material” means any substrate composed of fibers (typically glass or carbon) or other fillers incorporated together with polymeric or plastic materials (typically epoxy polymers).

[0237] Each and every combination of the features and examples described above is arguably covered by this invention. In view of the foregoing, this invention particularly relates to the following non-limiting aspects:

[0238] 1. A catalytic composition comprising essentially the following:

[0239] (i) metal compounds; and

[0240] (ii) Unlike the mixture in (i), the compound catalyzes the addition reaction between an olefinically unsaturated compound and a thiol, wherein the catalytic composition is substantially free of vanadium compounds.

[0241] 2. The catalytic composition according to aspect 1, wherein the catalytic composition is substantially free of reaction products of reactive compounds or active hydrogen compounds comprising acid functional groups, acid anhydride groups, and acid anhydride or polybasic acid.

[0242] 3. The catalytic composition according to any one of aspects 1 or 2, wherein the metal compound (i) comprises at least one of metal oxides, metal salts and organometallic compounds.

[0243] 4. The catalytic composition according to any one of aspects 1 to 3, wherein the metal compound (i) comprises an iron compound.

[0244] 5. The catalytic composition according to any one of aspects 1 to 4 above, wherein the compound (ii) comprises an organic compound containing N and / or P, such as a primary amine, a secondary amine, a tertiary amine, or a phosphine.

[0245] 6. The catalytic composition according to aspect 5 above, wherein the compound (ii) is selected from one or more of the following: oxazolidine, triethylamine, dimethylcyclohexylamine, dimethyloctylamine, dimethyldodecylamine, dimethylaminoethanol, tetramethylguanidine, diazabicyclooctane, diazabicycloundecene, diazabicyclononene, n-methyltriazabicyclodecene, trioctylphosphine, and triphenylphosphine.

[0246] 7. The catalytic composition according to aspect 5 or 6, wherein the molar ratio of nitrogen (e.g., in an amino or ammonium group) or phosphorus (e.g., in a phosphine or phosphonium group) in compound (ii) to the metal in metal compound (i) is from 0.4 to 500:1.

[0247] 8. The catalytic composition according to any one of aspects 1 to 7 above, wherein the metal compound (i) comprises an iron compound, the compound (ii) comprises a compound containing a secondary or tertiary amine group, and the molar ratio of the amine group to iron is 0.4 to 500:1.

[0248] 9. A curable composition comprising:

[0249] (a) Polyene;

[0250] (b) a polythiol, wherein the polythiol is present in an amount greater than 10% by weight based on the total weight of the resin solids in the curable composition; and

[0251] (c) A catalytic component comprising a catalytic composition according to any one of aspects 1 to 8 above; wherein the curable composition is substantially free of vanadium compounds, free radical polymerization initiators, and reaction products of reactive compounds or active hydrogen compounds including acid functional groups, acid anhydride groups, and acid anhydrides or polybasic acids.

[0252] 10. The curable composition according to aspect 9, wherein the polyene has the following structural formula:

[0253] A-(X) m

[0254] Where A is the organic moiety; X is the olefinic unsaturated moiety and m is at least 2, wherein the polyene A-(X) m Typically includes polyurethane (meth)acrylate or polyester (meth)acrylate.

[0255] 11. The curable composition according to aspect 10, wherein X is selected from -C(O)CR=CH2, -CH2-CHR=CH2 and mixtures thereof, wherein R is hydrogen or methyl.

[0256] 12. The curable composition according to any one of aspect 10 or aspect 11, wherein A contains groups selected from ester groups and urethane groups and / or derived from polyisocyanates.

[0257] 13. The curable composition according to any one of aspects 9 to 12 above, wherein the polythiol has 2 to 6 thiol groups.

[0258] 14. The curable composition according to any one of aspects 9 to 13, wherein the polythiol contains an ester group and / or is derived from a polyol.

[0259] 15. The curable composition according to any one of aspects 9 to 14 above, wherein the polythiol comprises a reaction product of a thiol-functional organic acid and a polyol.

[0260] 16. The curable composition according to any one of aspects 9 to 15 above, wherein the metal compound (i) of the catalytic composition comprises an iron compound, and is present in the curable composition in an amount of 1 ppm to 1000 ppm of metal based on the total weight of components (a) and (b) in the curable composition.

[0261] 17. The curable composition according to any one of aspects 9 to 16 above, wherein the compound (ii) of the catalytic composition is present in the curable composition in an amount of 0.001% by weight to 10% by weight based on the total weight of components (a) and (b) in the curable composition.

[0262] 18. The curable composition according to any one of aspects 9 to 17 above, wherein the equivalence ratio of the thiol functional group in the polythiol (b) to the olefinic unsaturated group in the polyene (a) is 0.1 to 10:1.

[0263] The invention will be further described with reference to the following examples. These examples are merely illustrative and not intended to be limiting. Unless otherwise indicated, all parts are by weight.

[0264] Example A

[0265] Prepare the pigment paste in a stainless steel beaker according to the following procedure:

[0266] Table 1

[0267]

[0268] 1 Pentaerythritol tetra(3-mercaptopropionate), from Bruno Bock Chemische Fabrik GmbH & Co. KG.

[0269] 2 The dispersant and flow aid are from BYK USA Inc.

[0270] 3 Pigments, from Huntsman.

[0271] 4 Talc, from Barretts Minerals Inc.

[0272] After adding each of charges 1 and 2 to the beaker, stir the mixture with a Cowles blade for five minutes. After adding charge 3 to the beaker, stir the mixture with a Cowles blade for 20 minutes. Then, place the mixture of Example A on a Hockmeyer mini-grinder equipped with 1.2–1.7 mm Zirconox grinding media for 3 hours, while placing grinding dry ice around the container to control the temperature. Dilute the mixture with 137 g of n-butyl acetate.

[0273] The example formulations listed in Table 2 were assembled and mixed by hand using a wooden spatula. The compositions of Examples 1A and 1D are comparative because they do not contain the metal compounds (i) found in the catalytic compositions of the present invention. The compositions of Examples 1B and 1E are comparative because they do not contain the compounds (ii) found in the catalytic compositions of the present invention. Examples 1C and 1F represent the curable compositions of the present invention.

[0274] A 15g sample of each type was placed in a scintillation tube for measuring liquid curing properties such as pot life and gel time. Pot life was determined by measuring the change in viscosity over time at 25°C using a Brookfield CAP 2000 viscometer with the #1 spindle set to 900 RPM. The time required for the initial viscosity to double is expressed as the pot life of the sample and is a good indicator of the amount of time available to apply the sample to a substrate.

[0275] Table 2

[0276]

[0277] 1 Pentaerythritol tetra(3-mercaptopropionate), from Bruno Bock Chemical Plant

[0278] 2 Pentafunctional acrylates are available from Allnex.

[0279] 3 Flow aid, from BYK Corporation, USA

[0280] 4 1 wt% n-butyl acetate solution of ferric chloride (III) hexahydrate

[0281] 5 5wt% n-butyl acetate solution of triethylenediamine

[0282] Using a nozzle with a 1.4mm diameter Compositions 1A, 1B, and 1C were applied using a GTI HVLP spray gun. Compositions 1D, 1E, and 1F were applied using a 3M Accu-Spray HG18 spray gun with a 1.8mm nozzle. All compositions in Table 2 were applied in two coats to 4-inch by 12-inch ACT cold-rolled steel sheets with an ED6060 electrocoating, available from ACT Laboratories, Inc., with a 5-minute ambient flash between coats. The target dry film thickness for pigment-free compositions 1A, 1B, and 1C was 2.0–3.0 mils, while the target dry film thickness for pigmented compositions 1D, 1E, and 1F was higher, at 3.0–4.0 mils. After coating, the film drying and curing properties of the applied sheets were tested at ambient temperature. No-tack time is the amount of time required for the coating to reach a certain level of dryness where no cotton fibers transfer to the coating surface after application and removal of the cotton ball. MEK double rubbing is reported as the number of double rubbings with a methyl ethyl ketone-soaked cloth required to dissolve the coating and make the substrate visible. MEK double friction was performed at 1-hour intervals after the membrane became non-adhesive, and the maximum number of double friction cycles recorded was 100.

[0283] As can be seen from Table 2, a longer pot life was achieved with the addition of ferric chloride (III). However, the combination of ferric chloride (III) and the catalyst is essential for the rapid establishment of long pot life, fast non-stick time, and solvent resistance.

[0284] Although specific examples of the invention have been described above for illustrative purposes, it will be apparent to those skilled in the art that many detailed changes may be made to the invention without departing from the invention as defined in the appended claims.

Claims

1. A coated substrate comprising (a) a substrate, the substrate comprising a metal, a glass, a wood, and / or a polymer; and (b) a curable composition applied as a coating to a surface of the substrate, wherein the curable composition comprises: (a) a polyene; (b) a polythiol present in an amount greater than 10 weight percent and up to 90 weight percent based on the total weight of components (a) and (b) in the curable composition; (c) a catalytic component consisting essentially of (i) a metal compound comprising an iron compound; and (ii) a compound different from (i) that catalyzes the addition reaction between ethylenically unsaturated compounds and thiols, wherein the compound (ii) is selected from the group consisting of a secondary amine compound and a tertiary amine compound, and wherein the molar ratio of nitrogen in the compound (ii) to metal in the metal compound (i) is from 0.4 to 500: 1, and wherein the catalytic component is essentially free of vanadium compounds, by "essentially free" is meant that if the vanadium compound is present, it is in an amount less than 0.1 weight percent based on the total weight of solids in the catalytic component; and (d) a pigment; and wherein the curable composition is essentially free of reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polybasic acids, by "essentially free" is meant that if the reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polybasic acids are present, they are in an amount less than 0.1 weight percent based on the total weight of solids in the curable composition, wherein the catalytic component is essentially free of reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polybasic acids, by "essentially free" is meant that if the reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polybasic acids are present, they are in an amount less than 0.1 weight percent based on the total weight of solids in the catalytic component.

2. The coated substrate of claim 1, wherein (1) both components (i) and (ii) of the catalytic component (c) are added to (a) and / or (b) as a single package, or (2) components (i) and / or (ii) of the catalytic component (c) are added to (a) and / or (b) of the curable composition in separate packages.

3. The coated substrate of claim 1 or 2, wherein the coating is used as a sealant.

4. The coated substrate of claim 1 or 2, wherein the coating is used as a primer coating or a topcoat.

5. The coated substrate of claim 1 or 2, wherein the metal compound (i) further comprises a tin compound, a cobalt compound, a magnesium compound, a manganese compound, or a mixture thereof.

6. The coated substrate of claim 5, wherein the metal compound (i) comprises iron (III) chloride.

7. A method of extending the pot life of a curable composition comprising (1) preparing a catalytic composition (c) consisting essentially of: (i) a metal compound comprising an iron compound; and (ii) a compound different from (i) that catalyzes the addition reaction between an ethylenically unsaturated compound and a thiol, wherein the compound (ii) is selected from the group consisting of a secondary amine compound and a tertiary amine compound, and wherein the molar ratio of nitrogen in the compound (ii) to metal in the metal compound (i) is from 0.4 to 500: 1, and wherein the catalytic composition (c) is substantially free of vanadium compounds, "substantially free of" means that if the vanadium compound is present, it is in an amount less than 0.1 wt% based on the total weight of solids in the catalytic composition (c); and (2) making the curable composition, wherein the curable composition comprises: (a) a polyene; (b) a polythiol present in an amount greater than 10 wt% and up to 90 wt% based on the total weight of components (a) and (b) in the curable composition; and (c) a catalytic composition; and wherein the curable composition is substantially free of reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polyacids, "substantially free of" means that if the reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polyacids are present, they are in an amount less than 0.1 wt% based on the total weight of solids in the curable composition, the catalytic composition (c) is substantially free of reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polyacids, "substantially free of" means that if the reactive compounds comprising acid functionality, acid anhydride groups, or reaction products of active hydrogen compounds with acid anhydrides or polyacids are present, they are in an amount less than 0.1 wt% based on the total weight of solids in the catalytic composition (c).

8. The method of claim 7, wherein: (1) adding both components (i) and (ii) of the catalytic composition (c) as a single package to (a) and / or (b), or (2) adding components (i) and / or (ii) of the catalytic composition (c) in separate packages to (a) and / or (b) of the curable composition.

9. The method of claim 7 or 8, wherein the metal compound (i) further comprises a tin compound, a cobalt compound, a magnesium compound, a manganese compound, or mixtures thereof.

10. The method of claim 9, wherein the metal compound (i) comprises iron (III) chloride.

Images