Two-part system

Abstract

The present teachings provide a two-part system and a method for using the two-part system, the two-part system comprising a first component including one or more epoxy resins and a second component including one or more phosphate esters, wherein the first and second components, when combined, form a cured elastomeric composition at a temperature of about 0° C. to about 50° C.

Description

[Technical Field]

[0001] The present teachings generally relate to compositions having a first component and a second component and methods of using the compositions. More specifically, the present teachings relate to two-component epoxy and phosphate ester-based cured elastomeric materials that can provide adhesion to a variety of substrates and can be used as foam-in-place gasket and sealant materials. [Background technology]

[0002] Gasket and sealant materials are frequently employed in the transportation and construction industries for a variety of purposes, such as providing one or more of the following: sealing, water and wind insulation, dirt and dust protection, and rattle protection.

[0003] Die-cut gasket and sealant materials have been adopted in industry, particularly in the transportation and construction industries. Typically, die-cut peel-and-stick gasket / sealant materials comprise a foam that is formed prior to application to a workpiece, and attachment to the workpiece is achieved via an adhesive, such as a pressure-sensitive adhesive. Some disadvantages of die-cut gasket / sealant materials include the additional labor and process resources associated with the die-cut process, the waste generated by the die-cutting process, and the need for a separate adhesive.

[0004] Foam-in-place reactions allow gasket and sealing materials to be dispensed directly onto workpieces. When room-temperature activation (e.g., expansion and curing) is desired, polyurethane-based foams are most commonly used. Polyurethane foams have many drawbacks, including the inclusion of isocyanate-functional monomers or oligomers, high VOC content, limited adhesion to certain substrates, poor hydrolysis resistance in wet or humid environments, unsuitability for use in slow-reacting systems, high sensitivity to temperature changes during dispensing and foaming, and the need for highly specific mixing ratios during formulation, especially for sensitive formulations. Another type of cure-in-place gasket / sealing material is silicone-based, which suffers from its own set of drawbacks, including poor adhesion to various substrates, poor tear resistance, high cost, and a lack of control over expansion and stiffness.

[0005] Phosphoric acid has been utilized for in-situ foaming reactions in polymeric materials as an alternative to polyurethane-based foams. However, the reaction time with phosphoric acid is very fast, making it less ideal for assembly processes that require time for the polymeric material to be placed on a surface prior to the foaming step. Therefore, a somewhat slower reaction time is preferable. In some situations, concerns may arise over phosphoric acid's low pH and splash hazard. Therefore, alternative materials with higher pH and reduced splash hazards would be preferable. Another drawback to using phosphoric acid is the difficulty of creating elastomeric materials due to the multifunctional nature of phosphoric acid. In addition, there is a significant difference in viscosity between phosphoric acid and polymeric materials. This poses challenges in both material manufacturing (e.g., mixing) and material storage. Phosphoric acid also has a much lower molecular weight than many polymeric materials, leading to undesirable mix ratios. Relatively equal mix ratios (typically monomeric or oligomeric materials to phosphoric acid) of 1:1, 2:1, or 4:1 would be preferable. Finally, the reactive nature of phosphoric acid makes it difficult to formulate adhesive and sealant materials, as many chemical components can become unstable due to their extremely high reactivity when utilized with phosphoric acid. The ability to include a variety of different moieties that may be beneficial for adhesion, physical or chemical compatibility, mechanical properties, or other reasons would be desirable.

[0006] WO 2016 / 149700 A1, which is incorporated herein by reference, discloses the use of phosphate esters as a replacement for phosphoric acid.

[0007] Despite the above teachings, there remains a need for improved elastomeric materials that can be utilized as gasketing and sealing materials. There is a need for foam-in-place, form-in-place gasketing and sealing materials that cure at room temperature (e.g., ambient temperature). There is a need for gasketing and sealing materials that provide expansion and crosslinking over a wider range of ambient temperatures than known gasketing and sealing materials. There is a need for gasketing and sealing materials that provide adhesion to a wide variety of substrates, including untreated and uncleaned substrates. There is a need for gasketing and sealing materials that utilize components that allow both curing and foaming without the need for additional components. There is a need for gasketing and sealing materials that provide desirable fire, smoke, and toxicity (FST) properties while eliminating or reducing the use of undesirable agents in imparting these properties. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2016 / 149700 [Patent Document 2] U.S. Patent No. 5,648,401 Summary of the Invention [Problem to be solved by the invention]

[0009] The present teachings provide one or more of the benefits described above. The gasket and sealing materials of the present teachings can be utilized for one or more of the following: cavity filling, sealing, or cushioning. [Means for solving the problem]

[0010] The present teachings provide a two-part system comprising a first component including one or more epoxy resins and a second component including one or more phosphate esters, wherein upon mixing the first and second components, the composition reacts to form a suitable finished product over a temperature range of about 0° C. to about 50° C. Optionally, a heat source may be used to reduce the time to reach a dry (e.g., tack-free) state that is dry to the touch.

[0011] The present teachings provide a two-part system comprising: a first component including one or more epoxy resins, which may be liquid or solid epoxy resins, flexible epoxy resins, or aliphatic multifunctional epoxy resins, one or more reactive diluents, and one or more first-component additives; and a second component including one or more phosphate esters, including a first phosphate ester, an optional second phosphate ester, and an optional third phosphate ester, and one or more second-component additives; wherein, upon mixing the first component and the second component to form a curable composition, the curable composition cures at a temperature of about 0° C. to about 50° C.

[0012] The second component may include a third phosphate ester. The second component may include at least one phosphate ester that is the product of a reaction between phosphoric acid and a monofunctional epoxy. One or more of the phosphate esters may include a phosphate ester derived from cashew nut shell liquid (CNSL). The second component may also include some added phosphoric acid.

[0013] The first component may include one or more first component additives. The one or more first component additives may include metal carbonates, which may be calcium carbonate, one or more minerals, reinforcing fibers, hydrophobic silica, or any combination thereof. The calcium carbonate may be present in an amount of about 2% to about 40% by weight of Side A (e.g., the first component) of the composition. The calcium carbonate may include ultrafine calcium carbonate, fine calcium carbonate, medium-fine calcium carbonate, or any combination thereof. The first component may include fine calcium carbonate in an amount of about 4% to about 8% by weight. The first component may include medium-fine calcium carbonate in an amount of about 13% to about 18% by weight.

[0014] The second component may include one or more second component additives. The one or more second component additives may include minerals, reinforcing fibers, hydrophobic silica, or any combination thereof.

[0015] The one or more epoxy resins may include one or more liquid epoxy resins, one or more flexible epoxy resins, one or more aliphatic multifunctional epoxy resins, one or more reactive diluents, or any combination thereof. The one or more epoxy resins may include a reaction product of epichlorohydrin and bisphenol A. The one or more epoxy resins may be present in an amount of about 5% to about 30% by weight. The one or more epoxy resins (which may be considered flexible epoxy resins) may include a difunctional glycidyl ether epoxy resin, an unmodified BPA-based epoxy resin, a multifunctional epoxidized polybutadiene resin, or any combination thereof. To produce an elastomeric final composition, one or more of the formulated product ingredients are expected to be flexible or elastomeric. The one or more epoxy resins may be present in an amount of about 10% to about 45% by weight. The one or more aliphatic multifunctional epoxy resins may include epoxidized sorbitol. The one or more aliphatic multifunctional epoxy resins may be present in an amount of about 1% to about 30% by weight. The one or more reactive diluents may include polyglycol diglycidyl ether, trimethylolethane triglycidyl ether, or both. The one or more reactive diluents may be present in an amount of about 4% to about 25% by weight.

[0016] The reaction temperature can be from about 0°C to about 50°C. The reaction temperature can be from about 15°C to about 25°C. The cure time of the curable composition can be from about 5 minutes to about 25 minutes, although a heat source could be used to accelerate the cure time. The cure time of the curable composition can be from about 7 minutes to about 10 minutes. The resulting reaction product can have a volume expansion of from about 100% to about 800%. The resulting reaction product can have a volume expansion of from about 400% to about 500%.

[0017] The curable composition can be dispensed onto any surface that can benefit from a foamed elastomeric material, including workpieces made from automotive parts. The reaction product of the curable composition can be a gasket or sealant. The two-part system can be free of latent curatives, cure accelerators, or both.

[0018] The teachings herein are further directed to a method comprising providing a two-part system comprising a first component and a second component, the first component comprising one or more epoxy resins and the second component comprising one or more phosphate esters; and mixing the first component and the second component to form a reaction product, wherein upon mixing the first component and the second component to form a curable composition, the curable composition cures at a temperature of from about 0° C. to about 50° C.

[0019] The second component may include two or three different phosphate esters. The first component may include one or more first component additives. The second component may include one or more second component additives. The one or more first component additives may include calcium carbonate.

[0020] The method may include curing the composition at a temperature of about 10°C to about 35°C. Curing may occur at a temperature of about 15°C to about 25°C. The cure time of the curable composition may be about 5 minutes to about 15 minutes. The cure time of the curable composition may be about 7 minutes to about 10 minutes. The reaction product may have a volume expansion of about 100% to about 800%. The reaction product may have a volume expansion of about 400% to about 500%.

[0021] The method may include dispensing the curable composition onto a workpiece comprising an automotive part. The reaction product of the curable composition may be a gasket or sealant. The two-part system may be free of latent curatives, accelerators, or both. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present teachings fulfill one or more of the above needs through improved compositions and methods described herein. The explanations and illustrations presented herein are intended to familiarize those skilled in the art with the present teachings, their principles, and their practical application. Those skilled in the art will be able to adapt and apply the present teachings in numerous forms that may be most appropriate to the requirements of a particular use. Accordingly, the specific embodiments of the present teachings illustrated are not intended to be exhaustive or to limit the present teachings. The scope of the present teachings should therefore be determined not with reference to the foregoing description, but instead with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and patent publications, are incorporated by reference for all purposes. Moreover, other combinations that can be gleaned from the appended claims are possible, and such combinations are also hereby incorporated by reference into this written description.

[0023] This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 62 / 828,693, filed April 3, 2019, the contents of which are incorporated herein by reference for all purposes.

[0024] The present teachings provide compositions that can be two-part compositions having an A-side (i.e., "first component") and a B-side (i.e., "second component") When mixed, the two-part composition forms a curable composition, and the reaction product, when fully cured, can be an elastomeric material that can be utilized as a gasket material and a sealing material.

[0025] The A-side may comprise one or more epoxy resins, one or more additives, one or more monomers, or both. The one or more epoxy resins may include one or more liquid epoxy resins, one or more flexible epoxy resins, one or more epoxy phenol novolac resins, one or more aliphatic multifunctional epoxy resins, one or more reactive diluents, one or more silane-modified epoxy resins, one or more monomers, or any combination thereof. The one or more additives may include one or more toughening agents (e.g., core-shell polymer particles), metal carbonates, minerals, reinforcing fibers, hydrophobic silica, platelet alumina, or any combination thereof.

[0026] The B-side may include one or more phosphate esters, phosphoric acid, one or more additives, one or more monomers, or any combination thereof. The one or more phosphate esters may include a first phosphate ester, a second phosphate ester, a third phosphate ester, or any combination thereof. The one or more additives may include minerals, reinforcing fibers, hydrophobic silica, or any combination thereof.

[0027] The one or more phosphate esters may be one or more customized phosphate esters. The one or more customized phosphate esters may be produced by reacting phosphoric acid with various alcohols. The one or more customized phosphate esters may be produced by reacting phosphoric acid with an epoxide group of a phosphate ester precursor (i.e., a component not yet reacted with phosphoric acid). The one or more customized phosphate esters may be produced by reacting phosphoric acid with a glycidyl ether of cashew nut shell liquid (CNSL), such as that sold under the trade name Cardolite® LITE 2513HP, commercially available from Cardolite Corporation, Monmouth Junction, New Jersey. The one or more customized phosphate esters may be produced by reacting phosphoric acid with a phenyl glycidyl ether, such as that sold under the trade name ERISYS® GE-13, commercially available from CVC Thermoset Specialties, Morestown, New Jersey. The one or more customized phosphate esters may be produced by reacting 2-ethylhexyl glycidyl ether with phosphoric acid, such as sold under the trade name ERISYS® GE-6, commercially available from CVC Thermoset Specialties, Inc., Morestown, New Jersey. The one or more customized phosphate esters may be produced by reacting epoxidized para-tert-butylphenol, such as sold under the trade name ERISYS® GE-11, commercially available from CVC Thermoset Specialties, Inc., Morestown, New Jersey, or any other monofunctional epoxy with phosphoric acid. The one or more customized phosphate esters may generally be the reaction product of a monoepoxide-functional molecule with phosphoric acid.

[0028] The one or more phosphate esters may be one or more commercially pre-reacted phosphate esters. If the one or more commercially pre-reacted phosphate esters were added to the B-side in place of the customized phosphate esters, they would likely result in a curable composition that reacts and foams more slowly, possibly due to a lower level of free phosphoric acid and therefore a higher pH on the B-side. The reaction and foaming of the one or more commercially pre-reacted phosphate esters can be improved (i.e., the reaction rate can be increased) by adding phosphoric acid to the B-side. The one or more commercially pre-reacted phosphate esters may have a pH of about 1 to about 3 in aqueous solution. The one or more commercially pre-reacted phosphate esters may have a viscosity of about 10,000 cP to about 42,500 cP at 25°C, as measured according to ASTM D445. The one or more commercially pre-reacted phosphate esters may be nonylphenol ethoxylated phosphate esters. Examples of suitable commercially pre-reacted phosphate esters would be those sold under the trade names Dextrol™ OC-110, Dextrol OC-40, and Strodex MO-100, commercially available from Ashland, Inc. (Covington, Kentucky).

[0029] Commercially pre-reacted phosphate esters may be present in the B-side. One or more commercially pre-reacted phosphate esters may be present in an amount of about 5% to about 50% by weight of the B-side. One or more commercially pre-reacted phosphate esters may be present in an amount of about 0.1% to about 30% by weight of the B-side. One or more commercially pre-reacted phosphate esters may be present in an amount of about 10% to about 14% by weight of the B-side. One or more commercially pre-reacted phosphate esters may be present in an amount of about 12% by weight of the B-side.

[0030] The one or more phosphate esters may be produced by reacting a range of stoichiometric ratios of phosphate ester precursor to phosphoric acid. The one or more phosphate esters may be produced by reacting a phosphate ester precursor to phosphoric acid of about 0.7:1 to about 1:0.7. The one or more phosphate esters may be produced by reacting a phosphate ester precursor to phosphoric acid of about 0.8:1 to about 1:0.8. The one or more phosphate esters may be produced by reacting a phosphate ester precursor to phosphoric acid of about 0.9:1 to about 1:0.9. The one or more phosphate esters may be produced by reacting a phosphate ester precursor to phosphoric acid of about 1:1. The one or more phosphate esters may be produced by reacting a phosphate ester precursor to phosphoric acid of about 0.8:1.

[0031] The cashew nut shell liquid (CNSL) may include chemicals commonly extracted from cashew nut shell liquid (CNSL), including anacardic acid, cardol, cardanol, or any combination thereof. Preferably, the glycidyl ether of cashew nut shell liquid (CNSL) is a glycidyl ether of cardanol.

[0032] The one or more phosphate esters may be selected from the mono-esters, di-esters, or triesters shown below. [ka]

[0033] One or more phosphate esters can result from the reaction of an epoxide group with phosphoric acid as depicted below. [ka]

[0034] The B-side may comprise one or more phosphate esters, one or more phosphate ester precursors, or both. The B-side may comprise one or more phosphate ester precursors that are combined with phosphoric acid before being combined with the A-side. The B-side may comprise one or more phosphate esters that have been pre-reacted (i.e., reaction of an epoxide with a phosphate) before addition to the B-side.

[0035] The first phosphate ester may be the reaction product of a glycidyl ether of cashew nut shell liquid (CNSL) (e.g., Cardolite® LITE 2513HP) with phosphoric acid. The second phosphate ester may be the reaction product of 2-ethylhexylglycidyl (e.g., ERISYS® GE-6) with phosphoric acid in a stoichiometry of about 1:1. The third phosphate ester may be the reaction product of phosphoric acid with 2-ethylhexylglycidyl ether (e.g., ERISYS® GE-6) in a stoichiometry of 0.8:1. However, there are numerous possibilities for the first, second, and third phosphate esters.

[0036] The first phosphate ester may be present in an amount of about 10% to about 60% by weight of the B-side. The first phosphate ester may be present in an amount of about 25% to about 35% by weight of the B-side. The first phosphate ester may be present in an amount of about 28% to about 32% by weight of the B-side. The first phosphate ester may be present in an amount of about 32% by weight of the B-side. The second phosphate ester may be present in an amount of about 5% to about 40% by weight of the B-side. The second phosphate ester may be present in an amount of about 15% to about 25% by weight of the B-side. The second phosphate ester may be present in an amount of about 18% to about 22% by weight of the B-side. The second phosphate ester may be present in an amount of about 21% by weight of the B-side. The third phosphate ester may be present in an amount of about 10% to about 65% by weight of the B-side. The third phosphate ester may be present in an amount of about 35% to about 45% by weight of the B-side. The third phosphate ester may be present in an amount of about 42% by weight of the B side. The third phosphate ester may be present in an amount of about 58% by weight of the B side. The third phosphate ester may be present in an amount of about 60% by weight of the B side.

[0037] The B-side may include phosphoric acid. The phosphoric acid may be orthophosphoric acid, polyphosphoric acid, or both. The phosphoric acid may be polyphosphoric acid. The phosphoric acid may be the free acid in one or more phosphate esters, added independently from one or more phosphate esters, or both. The addition of phosphoric acid to the B-side may result in increased expansion (e.g., foaming) of the resulting reaction product. The addition of phosphoric acid to the B-side increases the reactivity of the two-part system, helping to maintain a desired level of expansion, hardening, or both when the temperature is below 23°C.

[0038] The independently added phosphoric acid may be present in an amount of 85% or greater (i.e., "reagent grade") in aqueous solution. The independently added phosphoric acid may be present in an amount of about 1% to about 20% by weight of side B. The independently added phosphoric acid may be present in an amount of about 2% to about 6% by weight of side B. The independently added phosphoric acid may be present in an amount of about 4% by weight of side B.

[0039] The one or more phosphate esters produced from the reaction of phosphoric acid with a phosphate ester precursor may contain free acid. The one or more phosphate esters may have about 1% or more free acid, about 3% or more free acid, about 5% or more free acid, about 15% or less free acid, about 13% or less free acid, or even about 11% or less free acid.

[0040] Upon addition of sides A and B, the two-part system may effervescent as a result of the reaction of the metal carbonate or bicarbonate with the acid, resulting in the release of a gas (e.g., carbon dioxide, which acts as a chemical blowing agent). Such a reaction mechanism is described in U.S. Pat. No. 5,648,401, incorporated herein by reference for all purposes.

[0041] Reaction, foaming, or both may occur at about 50° C. or less, about 30° C. or less, about 20° C. or less, or even about 0° C. or less. Curing, foaming, or both may occur at about 0° C. or more, about 10° C. or more, or even about 20° C. or more. Curing, foaming, or both may occur at a temperature of about 10° C. to about 35° C. Curing, foaming, or both may occur at a temperature of about 10° C. Curing, foaming, or both may occur at room temperature (e.g., at a temperature of about 15° C. to about 25° C.). Curing, foaming, or both may occur at a temperature of about 23° C.

[0042] The present disclosure contemplates relatively fast cure times, foam times, or both, occurring without the addition of stimulation (e.g., at room temperature) compared to other curing agents or cure systems. The cure times of the reaction product may be 75 minutes or less, 50 minutes or less, 30 minutes or less, 20 minutes or less, 2 minutes or more, 8 minutes or more, or even 16 minutes or more. The cure times of the resulting reaction product may be from about 5 minutes to about 20 minutes. The cure times of the resulting reaction product may be about 10 minutes. The cure times of the resulting reaction product may be about 7 minutes. The cure times of the resulting reaction product may be about 5 minutes.

[0043] Foaming will begin before complete reaction of the resulting reaction product. The foaming time of the resulting reaction product (i.e., the time frame within which the two-part system will foam) can be 30 minutes or less, or even about 20 minutes or less. The foaming time of the reaction product can be from about 1 minute to about 10 minutes. The foaming time of the reaction product can be about 5 minutes. The foaming time of the reaction product can be about 7 minutes.

[0044] The A-side may include one or more epoxide-functional materials (i.e., one or more epoxy resins). The one or more epoxy resins may be any conventional dimeric, oligomeric, or polymeric epoxy resin. The one or more epoxy resins may contain at least one epoxide functional group (i.e., monofunctional) or may contain more than one epoxide functional group (i.e., multifunctional). The one or more epoxy resins may contain one or more epoxide functional groups, two or more epoxide functional groups, three or more epoxide functional groups, or even four or more epoxide functional groups. The one or more epoxy resins may be modified epoxy resins (e.g., silane-modified, elastomer-modified, etc.). The one or more epoxies may be aliphatic, cycloaliphatic, aromatic, etc., or any combination thereof. The one or more epoxies may be supplied as a solid (e.g., pellets, chunks, strips, etc., or any combination thereof) or as a liquid (e.g., liquid epoxy resin). However, if solid resins are used, it is contemplated that they will first be dissolved in a liquid resin or other suitable solvent. As used herein, unless otherwise specified, a resin is a solid resin if it is solid at a temperature of 23°C, and a liquid resin if it is liquid at a temperature of 23°C. The one or more epoxy resins may include one or more liquid epoxy resins, one or more flexible epoxy resins, one or more epoxy phenolic novolac resins, one or more aliphatic multifunctional epoxy resins, one or more reactive diluents, one or more silane-modified epoxy resins, or any combination thereof.

[0045] The two-part system may include one or more liquid epoxy resins. The one or more liquid epoxy resins could serve as a base for the epoxy resin component. The one or more liquid epoxy resins may be a reaction product of epichlorohydrin (hereinafter "EPH") with any conventional bisphenol. The one or more liquid epoxy resins may be a reaction product of EPH with bisphenol A (hereinafter "BPA") or bisphenol F (hereinafter "BPF"), or both. The one or more liquid epoxy resins (standard or commercial liquid epoxy resins) may have an epoxide equivalent weight (hereinafter "EEW") of about 100 g / eq to about 1000 g / eq, as measured according to ASTM D1652-97. The one or more liquid epoxy resins may have an epoxide percentage of about 20 to about 25. The one or more liquid epoxy resins may have a viscosity of 10 cP to about 100,000 cP at 25°C as measured according to ASTM D-445. An example of a suitable BPA-based liquid epoxy resin would be DER™ 331, commercially available from Oline Corporation (Clayton, Missouri). An example of a suitable BPF-based liquid epoxy resin would be YDF-170, commercially available from Kukdo Chemical Co. (Korea).

[0046] One or more liquid epoxy resins may be present as part of the A-side. The one or more liquid epoxy resins may be present in an amount of about 4% to about 50% by weight of the A-side. The one or more liquid epoxy resins may be present in an amount of about 10% to about 30% by weight of the A-side. The one or more liquid epoxy resins may be present in an amount of about 8% by weight of the A-side.

[0047] The two-part system may include one or more flexible epoxy resins. The one or more flexible epoxy resins may function to reduce the modulus of elasticity, increase the strain to failure, shorten the recovery time, reduce the degree of crosslink density in the reaction product, increase the impact resistance, improve adhesion, improve peel resistance, or any combination thereof. The one or more flexible epoxy resins may improve the gas trapping capabilities of the two-part system, in part, by acting as viscosity modifiers or by reducing gas permeability. The one or more flexible epoxy resins may be difunctional glycidyl ether epoxy resins, unmodified BPA-based epoxy resins, multifunctional epoxidized polybutadiene resins, or any combination thereof. The one or more flexible epoxy resins may have an EEW of about 260 to about 500, as measured according to ASTM D1652-97. The one or more flexible epoxy resins may have a viscosity of about 700 cP to about 500,000 cP as measured according to ASTM D445 at 25° C. Examples of suitable flexible epoxy resins include NC-514 (commercially available from Cardolite Corporation, Monmouth Junction, New Jersey), Araldite® PY4122 (commercially available from Huntsman Advanced Materials, Salt Lake City, Utah), Poly bd® 605E (commercially available from Cray Valley, Exton, Pennsylvania), or any combination thereof.

[0048] One or more flexible epoxy resins may be present in the A-side. The one or more flexible epoxy resins may be present in an amount of about 10% to about 50% by weight of the A-side. The one or more flexible epoxy resins may be present in an amount of about 35% to about 45% by weight of the A-side. The one or more flexible epoxy resins may be present in an amount of about 39% by weight of the A-side. The one or more flexible epoxy resins may include a difunctional glycidyl ether epoxy resin in an amount of about 10% to about 18% by weight of the A-side, an unmodified BPA-based epoxy resin in an amount of about 8% to about 16% by weight of the A-side, and a multifunctional epoxidized polybutadiene resin in an amount of about 8% to about 16% by weight of the A-side. The one or more flexible epoxy resins may include a difunctional glycidyl ether epoxy resin in an amount of about 14% by weight of the A-side, an unmodified BPA-based epoxy resin in an amount of about 12% by weight of the A-side, and a multifunctional epoxidized polybutadiene resin in an amount of about 12% by weight of the A-side. The two-component system may include the difunctional glycidyl ether epoxy resin, the cardanol-derived difunctional epoxy, and the multifunctional epoxidized polybutadiene resin in a ratio of about 1:1:1, respectively. The two-component system may include the difunctional glycidyl ether epoxy resin, the cardanol-derived difunctional epoxy, and the multifunctional epoxidized polybutadiene resin in a ratio of about 1:0.8:0.8, respectively. The two-component system may include the difunctional glycidyl ether epoxy resin, the cardanol-derived difunctional epoxy, and the multifunctional epoxidized polybutadiene resin in a ratio of about 1:0.9:0.9, respectively.

[0049] The two-part systems described herein may further include one or more epoxy phenolic novolac resins. The one or more epoxy phenolic novolac resins may function to impart chemical resistance, solvent resistance, temperature resistance, or any combination thereof, to the reaction product. The one or more epoxy phenolic novolac resins may be present as part of the A-side. The one or more epoxy phenolic novolac resins may have an EEW of about 165 g / eq to about 183 g / eq, as measured according to ASTM D1652-97. The one or more epoxy phenolic novolac resins may have an average epoxy functionality of about 2.1 to about 6.5. One of the primary functions of EPN resins is to increase network crosslink density through multi-functionality. This is important for controlling the reaction rate and the ability to prevent foam collapse during and / or after the reaction process. The one or more epoxy phenolic novolac resins may have a viscosity of about 18,000 cP to about 30,000 cP as measured in accordance with ASTM D445 at 25° C. Examples of suitable epoxy phenolic novolac resins include those sold under the trade names Epalloy 8250 and Epalloy 8330, commercially available from CVC Thermoset Specialties, Inc. (Morestown, New Jersey).

[0050] The one or more epoxy phenolic novolac resins may be present in an amount of about 30% to about 50% by weight of the A-side. The one or more epoxy phenolic novolac resins may be present in an amount of about 35% to about 45% by weight of the first component or A-side. The one or more epoxy phenolic novolac resins may be present in an amount of about 38% to about 42% by weight of the A-side. The one or more epoxy phenolic novolac resins may be present in an amount of about 42% by weight of the A-side. The one or more epoxy phenolic novolac resins may include an about 3.6-functional epoxy phenolic novolac resin present in an amount of about 2% to about 18% by weight of the A-side and an about 6.5-functional epoxy novolac resin present in an amount of about 22% to about 32% by weight of the A-side. The one or more epoxy phenolic novolac resins may include an about 3.6-functional epoxy phenolic novolac resin present in an amount of about 15% by weight of side A and an about 6.5-functional epoxy novolac resin present in an amount of about 28% by weight of side A. The two-part system may include the about 3.6-functional epoxy phenolic novolac resin and the about 6.5-functional epoxy phenolic novolac resin in a ratio of about 1:2 to about 1:3.

[0051] The two-part system may include one or more aliphatic multifunctional epoxy resins. The one or more aliphatic multifunctional epoxy resins may function to increase the degree of crosslinking of the reaction product, increase the chemical resistance of the reaction product, or both. These resins have the ability to increase the crosslink density of the reaction product while maintaining or enhancing the elastomeric properties of the resulting reaction product. Generally, multifunctional materials will decrease the elastomeric properties of the reaction product. The one or more aliphatic multifunctional epoxy resins may include epoxidized sorbitol. The one or more aliphatic multifunctional epoxy resins may have an EEW of about 160 g / eq to about 195 g / eq, as measured in accordance with ASTM D1652-97. The one or more aliphatic multifunctional epoxy resins may have a viscosity of about 4,000 cP to about 18,000 cP at 25°C, as measured in accordance with ASTM D445. Examples of suitable aliphatic multifunctional epoxy resins include those sold under the trade names ERISYS® GE-60 and ERISYS® GE-61, commercially available from CVC Thermoset Specialties, Inc. (Morestown, New Jersey).

[0052] One or more aliphatic multifunctional epoxy resins may be present as part of the A-side. The one or more aliphatic multifunctional epoxy resins may be present in an amount of about 5% to about 20% by weight of the A-side. The one or more aliphatic multifunctional epoxy resins may be present in an amount of about 8% to about 16% by weight of the A-side. The one or more aliphatic multifunctional epoxy resins may be present in an amount of about 10% to about 14% by weight of the A-side. The one or more aliphatic multifunctional epoxy resins may be present in an amount of about 12% by weight of the A-side.

[0053] The two-part system may include one or more reactive diluents. The one or more reactive diluents may function to lower the overall viscosity of the two-part system and, if monofunctional, to modify the dispensing process of the two-part system and the flow of the two-part system on a workpiece after dispensing, to reduce the degree of crosslinking of the reaction product. In statistically higher than difunctional systems, the diluents may increase crosslink density. One or more reactive diluents may be polymeric, thereby increasing the flexibility of the reaction product; one or more reactive diluents may be multifunctional, thereby promoting increased crosslinking and imparting chemical resistance to the reaction product; or both. The one or more reactive diluents may include polyglycol diglycidyl ether, trimethylolethane triglycidyl ether, or both. The one or more reactive diluents may have an EEW of about 100 g / equivalent to about 300 g / equivalent, as measured in accordance with ASTM D1652-97. The one or more reactive diluents may have a viscosity of from about 10 cP to about 1000 cP as measured in accordance with ASTM D445 at 25° C. An example of a suitable reactive diluent would be one sold under the tradename ERISYS® GE-31 and ERISYS® GE-24, commercially available from CVC Thermoset Specialties, Inc. (Morestown, New Jersey).

[0054] The one or more reactive diluents may be present in an amount of about 5% to about 20% by weight of the A-side. The one or more reactive diluents may be present in an amount of about 8% to about 16% by weight of the A-side. The one or more reactive diluents may be present in an amount of about 10% to about 14% by weight of the A-side. The one or more reactive diluents may be present in an amount of about 13% by weight of the A-side. The one or more reactive diluents may include polyglycol diglycidyl ether present in an amount of about 2% to about 6% by weight of the A-side and trimethylolethane triglycidyl ether present in an amount of about 6% to about 14% by weight of the A-side. The one or more reactive diluents may include polyglycol diglycidyl ether present in an amount of about 4% by weight of the A-side and trimethylolethane triglycidyl ether present in an amount of about 9% by weight of the A-side. The two-part system may comprise polyglycol diglycidyl ether and trimethylolethane triglycidyl ether in a ratio of about 1:2 to about 1:3, respectively.

[0055] The two-part system may include one or more silane-modified epoxy resins. The one or more silane-modified epoxy resins may function to impart improved adhesion to the reaction product, particularly to glass, metal, or both. An example of a suitable silane-modified epoxy resin would be sold under the trade name EPOKUKDO® KSR-177, commercially available from Kukdo Chemical (Korea). Another suitable material would be a silicone prepolymer having cycloaliphatic epoxide groups. An example of such a material is commercially available under the trade name Silmer EPC Di-50, available from Siltech Corporation, Ontario, Canada.

[0056] One or more silane-modified epoxy resins may be present in the A-side. The one or more silane-modified epoxy resins may be present in an amount of about 1% to about 15% by weight of the A-side. The one or more silane-modified epoxy resins may be present in an amount of about 2% to about 6% by weight of the A-side. The one or more silane-modified epoxy resins may be present in an amount of about 4% by weight of the A-side.

[0057] The two-part system may include one or more monomers. The one or more monomers may function to improve the adhesion properties of the reaction product, particularly to metal substrates, increase the flexibility of the reaction product, increase the impact resistance of the reaction product, or any combination thereof. The one or more monomers may be monofunctional, difunctional, or multifunctional. The one or more monomers may be the esterification reaction product of an alcohol and acrylic or methacrylic acid. The one or more monomers may be monofunctional acrylic monomers. Preferably, the one or more monomers may be a mixture of methacrylate acid ester and 2-(2-ethoxyethoxy)ethyl acrylate. An example of a suitable monomer may be sold under the trade name SR9050, commercially available from Sartomer, Inc. (Eskton, Pennsylvania).

[0058] The two-part system may include one or more monomers in the A side, the B side, or both. The one or more monomers may be present in an amount of about 0.1% to about 26% by weight of the A side, the B side, or both the A and B sides combined. The one or more monomers may be present in an amount of about 12% to about 24% by weight of the A side, the B side, or both the A and B sides combined. The one or more monomers may be present in an amount of about 14% to about 22% by weight of the A side, the B side, or both the A and B sides combined. The one or more monomers may be present in an amount of about 18% by weight of the A side, the B side, or both the A and B sides combined.

[0059] The cure rate, the degree of crosslinking, or both, can be a function of the functionality of the two-part system (side A and side B). Higher functionality (i.e., the average number of functional groups on one or more polymerizable components) will be desirable for two-part systems having pre-polymerized components with shorter polymer lengths (i.e., lower viscosities) because the lack of structural backbone resulting from the shorter polymers is compensated for by a higher degree of crosslinking. Lower functionality will be desirable for two-part systems having pre-polymerized components with longer lengths (i.e., typically resulting in higher viscosities) because the presence of more structural backbone resulting from the longer polymers eliminates the need for high functionality.

[0060] The functionality of the B-side may be reduced, at least in part, by reaction of the metal carbonate with phosphoric acid and phosphate esters in the A-side, potentially resulting in reduced functionality of the B-side. The A-side may include higher functionality components to compensate for the reduced functionality of the B-side. The A-side may also be formulated with increased functionality by using reactive components with functionality greater than 2.

[0061] The two-part system may include one or more additives, which may include one or more reinforcing agents, calcium carbonate, minerals, reinforcing fibers, hydrophobic silica, platelet alumina, or any combination thereof.

[0062] The two-part system may include one or more toughening agents. The one or more toughening agents may function to dissipate energy within the reaction product (i.e., increase impact resistance). The one or more toughening agents may contribute to increased T-peel strength. The one or more toughening agents may comprise a thermoplastic resin, a thermoset or thermosettable resin, an elastomer, or the like, or any combination thereof. The one or more toughening agents may include an elastomer (including elastomer-containing materials), a core-shell polymer (which may include, but is not limited to, an elastomer), or both.

[0063] The core-shell polymer may comprise a first polymeric material (i.e., core material) and a second polymeric material (i.e., shell material). The first polymeric material may be entirely encapsulated by the second polymeric material. The core-shell polymer may comprise the first polymeric material in an amount of about 30% by weight or more, 50% by weight or more, or even 70% by weight or more. The first polymeric material, the second polymeric material, or both may comprise one polymer, two polymers, three polymers, or even more than three polymers combined together, reacted together (e.g., sequentially), or combined and reacted together, or may be part of separate or the same core-shell polymer system. Examples of suitable core-shell polymers include those sold under the trade names Kane Ace™ MX-267 and MX-257, both commercially available from Kaneka North America LLC (Pasadena, Texas).

[0064] The core-shell polymer may be present in an amount of about 1% to about 25% by weight of the A side, the B side, or both the A and B sides combined (e.g., if present in a 10% amount, it may be present in a 5% amount on the A side and a 5% amount on the B side). The core-shell polymer may be present in an amount of about 5% to about 20% by weight of the A side, the B side, or both the A and B sides combined. The core-shell polymer may be present in an amount as low as about 5% by weight of the A side, the B side, or both the A and B sides combined. The core-shell polymer may be present in an amount of about 17% by weight of the A side, the B side, or both the A and B sides combined.

[0065] The two-part system may include one or more metal carbonates. The one or more metal carbonates may function to generate gas in the presence of an acid, to act as a filler, to control the initiation or total extent of the foaming (e.g., expansion) process, or both. The one or more metal carbonates may be metal carbonates or metal bicarbonates. Examples of suitable fillers include calcium carbonate, nickel carbonate, barium carbonate, sodium bicarbonate, and potassium bicarbonate. Preferably, the one or more metal carbonates may include calcium carbonate. The particle size of the metal carbonate, metal bicarbonate, or both can control the expansion and hardening of the two-part system; therefore, the total surface area of ​​the metal carbonate, metal bicarbonate, or both available to react with the acid is a function of both the particle size of the metal carbonate, metal bicarbonate, or both and the amount present in the two-part system.

[0066] Calcium carbonate (CaCO3) may be present as one or more calcium carbonate fillers. The one or more calcium carbonate fillers may have a median particle size of about 1 micron to about 50 microns. The calcium carbonate may be a medium fine particle size. For example, the medium fine calcium carbonate may have a median particle size of about 22 microns. An example of a suitable medium fine calcium carbonate would be Hubercarb® Q200, commercially available from Huber Engineered Materials, Atlanta, Georgia. The calcium carbonate may be a fine particle size. For example, the fine calcium carbonate may have a median particle size of 4 microns. An example of a suitable fine calcium carbonate would be Hubercarb® Q4, commercially available from Huber Engineered Materials, Atlanta, Georgia. The calcium carbonate may be an ultra-fine particle size. For example, the ultra-fine calcium carbonate may have a median particle size of about 1 micron. An example of a suitable ultrafine calcium carbonate would be Hubercarb® Q2, commercially available from Huber Engineered Materials, Atlanta, Ga. The two-part system may include medium-fine calcium carbonate, fine calcium carbonate, ultrafine calcium carbonate, or any combination thereof.

[0067] The calcium carbonate may be present in an amount of about 1% to about 25% by weight of the A-side. The calcium carbonate may be present in an amount of about 4% to about 18% by weight of the A-side. The calcium carbonate may be present in an amount of about 8% to about 12% by weight of the A-side. The calcium carbonate may be present in an amount of about 20% by weight of the A-side. The calcium carbonate may include both fine calcium carbonate present in an amount of about 4% to about 8% by weight of the A-side and medium fine calcium carbonate present in an amount of about 13% to about 18% by weight of the A-side. The calcium carbonate may include both fine calcium carbonate present in an amount of about 6% by weight of the A-side and medium fine calcium carbonate present in an amount of about 15% by weight of the A-side. The calcium carbonate may include both fine calcium carbonate present in an amount of about 5% by weight of the A-side and medium fine calcium carbonate present in an amount of about 5% by weight of the A-side. The ratio of medium fine calcium carbonate to fine calcium carbonate may be about 3:1 to about 1:3. The ratio of medium fine calcium carbonate to fine calcium carbonate may be about 1:1.

[0068] The calcium carbonate may include a coating. The coating may be any material that decomposes during the activation process, the expansion process, or both to retard and / or slow expansion. The coating may be a wax, a fatty acid, or a combination thereof.

[0069] The two-part system may include one or more minerals. The one or more minerals (i.e., "mineral reinforcement") may function to structurally reinforce the reaction product. The one or more minerals may improve the tensile strength, flexural strength, or both, of the reaction product. The one or more minerals may be any suitable silicate mineral, including, but not limited to, inosilicates (e.g., wollastonite) and phyllosilicates (e.g., kaolinite, vermiculite, talc, muscovite, etc.). The characteristic external shape of individual crystals or groups of crystals of the one or more minerals may be needle-like or acicular. The median particle size of the one or more minerals may be from about 10 microns to about 20 microns. The median particle size may be from about 12 microns to about 18 microns.

[0070] The one or more minerals may include wollastonite (CaSiO). The wollastonite may be relatively pure (i.e., less than 2% by weight of impurities such as other metal oxides). The wollastonite may contain impurities, including oxides of one or more of iron, magnesium, manganese, aluminum, potassium, sodium, or strontium, which substitute for calcium in the mineral structure. Examples of suitable wollastonite include those sold under the trade names NYGLOS® 12 and NYGLOS® 8, commercially available from NYCO Minerals Inc. (Willsboro, NY).

[0071] One or more minerals may be present as part of the A-side, the B-side, or both. Wollastonite may be present in an amount of about 0.1% to about 10% by weight of the A-side, the B-side, or both sides A and B combined. Wollastonite may be present in an amount of about 3% to about 7% by weight of the A-side, the B-side, or both sides A and B combined. Wollastonite may be present in an amount of about 4% by weight of the A-side, the B-side, or both sides A and B combined.

[0072] Calcined kaolin clay may be present as part of side A. The calcined kaolin clay may be present in an amount of about 0.1% to about 5% by weight of side A. The calcined kaolin clay may be present in an amount of about 1% to about 4% by weight of side A, side B, or a combination of both sides A and B. The calcined kaolin clay may be present in an amount of about 2% by weight of side A.

[0073] The two-part system may include one or more reinforcing fibers. The reinforcing fibers may function to structurally reinforce the reaction product. The one or more reinforcing fibers may improve the tensile strength, flexural strength, or both, of the reaction product. The one or more reinforcing fibers may be present in the A-side, the B-side, or both. The one or more reinforcing fibers may be uniformly dispersed within the A-side, the B-side, or both. The one or more reinforcing fibers may comprise polymer fibers, glass fibers (i.e., glass fiber), or both. The polymer fibers may include nylon, polyamide, polyester, polypropylene, polyethylene, polytetrafluoroethylene, aramid fibers (e.g., Kevlar®), etc., or any combination thereof. The glass fibers may include aluminoborosilicate glass ("E-glass"), alkali-lime glass ("A-glass" or "C-glass"), electrical / chemical resistant glass ("E-CR-glass"), borosilicate glass ("D-glass"), aluminosilicate glass ("R-glass" or "S-glass"), or any combination thereof. The reinforcing fibers may be chopped fibers. The reinforcing fibers may have a chopped length of about 0.1 cm or more, about 0.3 cm or more, or even about 0.6 cm or more. The reinforcing fibers may have a chopped length of about 2.0 cm or less, about 1.5 cm or less, or even about 1.0 cm or less. An example of a suitable glass fiber would be chopped strand commercially available from Jushi USA, Inc. (Columbia, South Carolina).

[0074] The reinforcing fibers may be present in an amount on the order of about 0.01% to about 3% by weight of the A-side, the B-side, or both sides A and B combined. The reinforcing fibers may be present in an amount on the order of about 0.1% to about 1% by weight of the A-side, the B-side, or both sides A and B combined. The reinforcing fibers may be present in an amount on the order of about 0.2% by weight of the A-side, the B-side, or both sides A and B combined. The two-part system may include one or more thixotropes to control viscosity.

[0075] The two-part system may include hydrophobic silica. The hydrophobic silica could function to control viscosity (e.g., thicken), control thixotropy, increase hydrophobicity, or achieve a combination thereof. The hydrophobic silica may be fumed silica. The hydrophobic silica may be surface-treated. For example, the hydrophobic silica may be fumed silica surface-treated with polydimethylsiloxane (hereinafter "PDMS") or hexamethyldisilazane (hereinafter "HMDZ"). The hydrophobic silica may be present as part of side A, side B, or both. Examples of suitable hydrophobic silicas include those sold under the tradename AEROSIL® R202, commercially available from Evonik Corporation (Parsipani, New Jersey), and those sold under the tradename CABO-SIL® TS-530 and TS-720, commercially available from Cabot Corporation (Boston, Massachusetts).

[0076] The hydrophobic silica may be present in an amount of about 0.25% to about 6% by weight of the A-side, the B-side, or both the A-side and the B-side combined. The hydrophobic silica may be present in an amount of about 0.5% to about 4% by weight of the A-side, the B-side, or both the A-side and the B-side combined. The hydrophobic silica may be present in an amount of about 1% to about 2% by weight of the A-side, the B-side, or both the A-side and the B-side combined. The hydrophobic silica may be present in an amount of about 0.5% to about 2% by weight of the A-side. The hydrophobic silica may be present in an amount of about 3% to about 5% by weight of the B-side. The ratio of hydrophobic silica in the A-side to hydrophobic silica in the B-side may be about 1:6 to about 6:1. The ratio of hydrophobic silica in the A-side to hydrophobic silica in the B-side may be about 1:4. The ratio of hydrophobic silica in the A-side to hydrophobic silica in the B-side may be about 1:2 to about 2:1.

[0077] The two-part system may include platelet alumina. The platelet alumina may function to impart hardness, thermal shock resistance, mechanical shock resistance, high heat capacity, high electrical resistivity, or any combination thereof, to the reaction product. The platelet alumina may be present on side A, side B, or both. The platelet alumina may be alpha alumina that has been converted to its corundum form (i.e., crystalline aluminum oxide) and sintered, or may be provided as graded granules or powder. The platelet alumina may be graded (i.e., size-fractionated) from about 44 microns to about 4760 microns. The platelet alumina may be graded to about 44 microns.

[0078] The tabular alumina may be present in an amount of about 0.1% to about 15% by weight of the A side, the B side, or both the A and B sides combined. The tabular alumina may be present in an amount of about 4% to about 12% by weight of the A side, the B side, or both the A and B sides combined. The tabular alumina may be present in an amount of about 5% by weight of the A side. The tabular alumina may be present in an amount of about 10% by weight of the A side.

[0079] The two-part system may include one or more functional additives to improve one or more various properties of the composition. Examples of suitable functional additives may include antioxidants, antiozonants, UV absorbers, antistatic agents, colorants, coupling agents, curing agents, flame retardants, blowing agents, heat stabilizers, impact modifiers, lubricants, plasticizers, preservatives, processing aids, stabilizers, and the like, and any combination thereof.

[0080] The viscosity of the A-side, the B-side, or both may be sufficiently high at 23° C. to prevent unwanted flow of the two-part system into the area adjacent to the dispense bead when the two-part system is dispensed onto a workpiece, or to control flow into the area adjacent to the dispense bead (i.e., allow a desired amount of flow) when the two-part system is dispensed. The viscosity of the A-side, the B-side, or both required to prevent or control unwanted flow may depend on the size of the dispensed bead. For example, the thicker the dispensed bead of the two-part system, the higher the viscosity required to prevent or control unintended flow. At very low shear rates approximating slack conditions, the viscosity of the A-side at 23° C. may be from about 20,000 cP to about 50,000 cP, or even from about 35,000 cP to about 45,000 cP. The viscosity of the A-side and the B-side at 23° C. may be from about 250,000 cP to about 400,000 cP. The viscosity of the A-side at 10° C. may be from about 280,000 cP to about 350,000 cP, or even from about 300,000 cP to about 325,000 cP. The viscosity of the B-side at 23° C. may be from about 20,000 cP to about 50,000 cP, or even from about 35,000 cP to about 45,000 cP. The viscosity of the B-side at 10° C. may be from about 130,000 cP to about 220,000 cP, or even from about 175,000 cP to about 195,000 cP.

[0081] The two-part system may expand, upon mixing of sides A and B, by more than about 50%, more than about 100%, more than about 200%, less than about 800%, less than about 700%, or less than about 600% of the original volume of the two-part system. The two-part system may expand by about 400% to about 500% of the original volume of the two-part system. The two-part system may expand by about 400% of the original volume of the two-part system.

[0082] The two-part system may be free of curing agents (i.e., traditional curing agents), cure accelerators, or both. Typical curing agents include Lewis bases (i.e., anionic catalysts), Lewis acids (i.e., cationic catalysts), UV catalysts, amines, anhydrides, phenols, thiols, or any combination thereof. Instead of the aforementioned curing agents, the two-part system can be cured by a phosphoric acid-catalyzed polymerization reaction between the phosphate ester and epoxide groups, hydroxyl groups, or both. The two-part system may be cured and expanded by the chemical interaction of the phosphate ester and a metal carbonate. It has been found that the disclosed curing and expansion system can reduce formulation complexity by reducing the overall number of components (i.e., curing agents, cure accelerators, and blowing agents), although achieving desired expansion and cure times can be challenging to optimize.

[0083] In one non-limiting embodiment of the present teachings, a two-part system may include, in side A ("first component"), one or more of the following: liquid epoxy resin, flexible epoxy resin, aliphatic multifunctional epoxy resin, reactive diluent, aramid pulp, medium fine calcium carbonate, fine calcium carbonate, hydrophobic silica, and wollastonite. The two-part system may include, in side B ("second component"), one or more of the following: first phosphate ester, second phosphate ester, third phosphate ester, aramid fiber, and hydrophobic silica.

[0084] The two-part system may be mixed together at an A-side to B-side ratio of 1:4 to 4:1. The two-part system may be mixed together at an A-side to B-side ratio of 1:2 to 2:1. The two-part system may be mixed together at an A-side to B-side ratio of 1:1. The two-part system may be mixed together at an A-side to B-side ratio of 2:1.

[0085] Non-limiting example formulation ranges according to the present teachings are provided in Table 1 below. [Table 1]

[0086] One important aspect of the gasket and sealant materials discussed herein is that they have improved compression set (e.g., the resistance of a composition to permanent deformation after an applied force is removed, according to ASTM D3571-17). Lack of satisfactory compression set results in a failure of the elastomeric material to seal against water, dust, and wind insulation and rattle protection. Test samples were compressed to 50% of their cube dimensions. The compressed cubes were then placed in a 70°C oven for 22 hours. They were then removed and kept at ambient temperature for a recovery time of 30 minutes. The resulting measured deformation was less than 10%. In addition to having a high recovery force at compression set, low compression stiffness is also desirable.

[0087] It would be desirable to achieve a moderate compression set (e.g., less than 10% deformation and low compression stiffness), a uniform cell structure, long elastomeric chains, and a partially open-cell composition while maintaining foam integrity. The ability to recover after deformation may be related to maintaining the high elastic portion of the complex modulus relative to the loss modulus. Storage and loss moduli are often expressed as G' (shear storage modulus) and G'' (shear loss modulus), measured via means such as dynamic mechanical analysis (DMA). Therefore, it follows that structural aspects of polymer structure that contribute to recovery relative to permanent deformation (e.g., creep) are desirable. This includes incorporating elastic elements into the molecule and methods to make the material less thermoplastic (i.e., higher crosslink density) in addition to a uniform cell structure. To achieve a uniform cell structure, a combination of finely divided metal carbonates, aliphatic multifunctional epoxy resins, and epoxidized polybutadiene resins may be utilized. To maintain a higher crosslink density, an aliphatic multifunctional epoxy resin may be utilized. To improve elastomeric properties, epoxidized polybutadiene resin, difunctional glycidyl ether epoxy resin, low-viscosity epoxy resin (reaction product of epichlorohydrin and polypropylene glycol), and silicone prepolymer with cycloaliphatic epoxy groups may be utilized on the A-side. To improve elastomeric properties, a first phosphate ester (reaction product of glycidyl ether cashew nut shell liquid and phosphoric acid) may be used on the B-side. Silicone prepolymer with cycloaliphatic epoxy groups may also contribute to increased open time.

[0088] Table 2 provides technical data for formulations according to the present teachings at a reaction temperature of 23°C. "Peak exotherm" refers to the peak temperature reached during cure and is a function of both the degree of crosslinking and the cure rate; thus, a higher degree of crosslinking will result in a higher exothermic reaction, and a higher cure rate will result in a higher peak exotherm, since the reaction product will take up heat from the exothermic reaction faster than it can dissipate it. Mechanical properties were determined according to ASTM D1621. Test samples were compressed to 50% of their cubic dimensions. The crosshead speed was held constant at 12.7 mm / min. [Table 2]

[0089] Additional examples of formulations according to the present teachings are provided below in Table 3. Amounts are expressed as weight percent. The stoichiometry of phosphate ester precursor to phosphoric acid is given in parentheses. [Table 3]

[0090] Table 4 provides technical data for the formulations from Table 1 at a test temperature of 23°C. Compression modulus may be a function of the compressive stress (force per unit area) applied to the sample and the resulting compression (deformation). Therefore, a low compression modulus is typically desirable for elastomeric materials. Given two samples with uniform compression modulus, the sample with a lower density suggests a stiffer reaction product matrix, which translates to a more highly crosslinked product. When viewed as a density-to-compression modulus ratio, a lower ratio may indicate an overall stiffer reaction product matrix. Comparative Example A may be a conventional die-cut PSA-backed pre-foamed gasket. Compression properties were determined according to ASTM D1621 using a 25.4 mm cube. The test sample was compressed to 50% of the cube dimension. The crosshead speed was held constant at 12.7 mm / min. [Table 4]

[0091] Additional examples of formulations according to the present teachings are provided below in Table 5. Amounts are expressed in weight percent. The stoichiometry of phosphate ester precursor to phosphoric acid is given in parentheses. [Table 5]

[0092] The two-part system may be provided as a side-by-side cartridge, pail, or drum. The two-part system may be mixed prior to application to the workpiece. The two-part system may be applied to the workpiece via any suitable dispenser capable of mixing the two-part system prior to application to the workpiece. For example, the two-part system may be dispensed onto the workpiece via a static mixer configured to deliver a mixed curable composition having the appropriate mix ratio as described herein.

[0093] The resulting reaction product provides excellent adhesion to many substrates with fast cure times. The resulting reaction product may provide excellent adhesion to glass, metal, polymers (e.g., thermoplastics, thermoset or thermosettable resins, or elastomers), or any combination thereof. In particular, the reaction product provides excellent adhesion to thermoplastics.

[0094] The two-part system can be cured and / or expanded before or after full assembly of the workpieces to which it is applied. For example, the two-part system can be dispensed onto a first workpiece, cured and / or expanded, and then a second workpiece complementary to the first workpiece can be applied onto the first workpiece. As another example, the two-part system can be dispensed onto a first workpiece, and a second workpiece complementary to the first workpiece can be applied onto the first workpiece, after which the two-part system can be cured and / or expanded. A two-part system that cures and / or expands after full assembly of the workpieces could expand to fill the space between the first and second workpieces. The first workpiece, the second workpiece, or both may include a groove, and the two-part system may be dispensed into the groove, or expand into the groove, or dispensed into and expand into the groove. The two-component material may be dispensed into a cavity.

[0095] The two-part system can be used in transportation applications. The two-part system can be used in automotive applications. The two-part system can be used in applications including, but not limited to, vehicle interiors, vehicle exteriors, HVAC ducts, side mirrors, electronics enclosures, taillights, headlights, commercial vehicles, construction, etc.

[0096] The present teachings provide a method that may include providing a two-part system including an A-side (i.e., first component) and a B-side (i.e., second component). The A-side includes one or more epoxy resins, and the B-side includes one or more phosphate esters and, optionally, phosphoric acid. The A-side and B-side can be mixed to form a curable composition. The method may include curing the curable composition at a temperature less than 50°C, thereby forming a reaction product. The method may include mixing the first component and the second component to form a reaction product. The method may include curing the reaction product of the first component and the second component at a temperature less than 50°C. The method may be employed with an A-side that includes one or more epoxy resins, calcium carbonate, or both. The method may be employed with a B-side that includes one or more phosphate esters, phosphoric acid, or both. The method may be employed with an A-side, B-side, or both that includes one or more additives.

[0097] Use of the teachings herein may result in gaskets exhibiting sufficient flame retardancy to meet one or more of the requirements for demonstrating flame retardancy (e.g., meeting vertical burn and / or smoke density requirements (or any other requirements)) set forth in 14 C.F.R. 25.853 and 14 C.F.R. 25.856 (U.S. Department of Transportation Code of Federal Regulations for Passenger Cabin Interiors, including but not limited to 14 C.F.R. 25.853(a) and Reference Appendix F and the procedures referenced therein), both of which are incorporated by reference for all purposes.

[0098] As used herein, unless otherwise stated, the teachings contemplate that any member of a genus (list) may be excluded from the genus and / or any member of a Markush grouping may be excluded from the grouping.

[0099] Unless otherwise stated, any numerical value set forth herein includes all values ​​from the lower value to the upper value in increments of one unit, provided that there is a separation of at least two units between any lower value and any upper value. As an example, if an amount of an ingredient, property, or value of a process variable, such as temperature, pressure, or time, is stated to be, for example, from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, intermediate range values ​​(e.g., from 15 to 85, from 22 to 68, from 43 to 51, from 30 to 32, etc.) are intended to be within the scope of the teachings herein. Similarly, individual intermediate values ​​are also within the scope of the teachings. For values ​​less than one, one unit is considered to be 0.0001, 0.001, 0.01, or 0.1, accordingly. These are merely examples of what is specifically intended, and all possible combinations of numerical values ​​between the lowest and highest values ​​listed are considered to be expressly set forth within this application in a similar manner. As can be seen, any teaching herein of an amount expressed as "parts by weight" also contemplates that the same range be expressed in terms of weight percent. Thus, a range expression such as "at least 'x' parts by weight of the resulting composition" also contemplates a teaching of a range in weight percent of the resulting composition for the same recited amount "x."

[0100] Unless otherwise stated, all ranges include both endpoints and all numbers between the endpoints. The use of "about" or "approximately" in connection with a range applies to both ends of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30," inclusive of at least the specified endpoint. Unless otherwise stated, teachings using the term "about" or "approximately" in conjunction with a numerical quantity encompass teachings of the stated amount as well as teachings of approximations of that stated amount. As an example, a teaching of "about 100" encompasses the teaching of "100."

[0101] The disclosures of all articles and references, including patent applications and patent publications, are incorporated by reference for all purposes. The term "consisting essentially of" to describe a combination is intended to include the identified elements, ingredients, components, or steps, as well as such other elements, ingredients, components, or steps that do not materially affect the basic and novel characteristics of the combination. The use herein of the terms "comprising" or "including" to describe a combination of elements, ingredients, components, or steps also contemplates embodiments that consist of or consist essentially of the elements, ingredients, components, or steps in question.

[0102] A plurality of elements, ingredients, components, or steps may be provided by a single integrated element, ingredient, component, or step. Alternatively, a single integrated element, ingredient, component, or step may be divided into separate elements, ingredients, components, or steps. The disclosure of "a" or "one," which are translations of the original "a" or "one" to describe an element, ingredient, component, or step, is not intended to exclude additional elements, ingredients, components, or steps.

[0103] The present invention can be embodied, for example, as follows. [Embodiment 1] It is a two-part system, a. a first component comprising one or more epoxy resins; b. a second component comprising one or more phosphate esters; A two-part system, wherein the first component and the second component, when mixed, form an elastomeric curable composition over a temperature range of about 0°C to about 50°C. [Embodiment 2] 2. The two-part system of embodiment 1, wherein the second component comprises at least two or even at least three of the one or more phosphate esters. [Embodiment 3] 3. The two-part system of claim 1 or claim 2, wherein the one or more phosphate esters comprise a phosphate ester derived from cashew nut shell liquid (CNSL). [Embodiment 4] 4. The two-part system of any one of the preceding embodiments, wherein the one or more phosphate esters comprise a phosphate ester derived from 2-ethylhexyl glycidyl ether. [Embodiment 5] 5. The two-part system of any one of the preceding embodiments, wherein the first component comprises one or more first component additives. [Embodiment 6] 6. The two-part system of claim 5, wherein the one or more first component additives comprise one or more of calcium carbonate, minerals, reinforcing fibers, hydrophobic silica, or any combination thereof. [Embodiment 7] 7. The two-part system of any one of the preceding embodiments, comprising calcium carbonate present in an amount of about 5% to about 25% by weight. [Embodiment 8] 8. The two-part system of any one of the preceding embodiments, comprising ultrafine calcium carbonate, fine calcium carbonate, medium fine calcium carbonate, or any combination thereof. [Embodiment 9] 9. The two-part system of any one of the preceding claims, wherein the first component comprises the fine calcium carbonate in an amount of about 4% to about 8% by weight and / or the medium fine calcium carbonate in an amount of about 13% to about 18% by weight. [Embodiment 10] 10. The two-part system of any one of the preceding embodiments, wherein the second component comprises one or more second component additives. [Embodiment 11] 8. The two-part system of claim 7, wherein the one or more second component additives comprise one or more of a mineral, a reinforcing fiber, a hydrophobic silica, or any combination thereof. [Embodiment 12] 12. The two-part system of any one of the preceding claims, wherein the one or more epoxy resins comprise one or more liquid epoxy resins, one or more flexible epoxy resins, one or more aliphatic multifunctional epoxy resins, one or more reactive diluents, or any combination thereof. [Embodiment 13] 13. The two-part system of any one of the preceding embodiments, comprising one or more liquid epoxy resins comprising the reaction product of epichlorohydrin and bisphenol A. [Embodiment 14] 14. The two-part system of any one of the preceding embodiments, comprising one or more liquid epoxy resins present in an amount from about 6% to about 30% by weight. [Embodiment 15] 15. The two-part system of any one of the preceding claims, comprising one or more flexible epoxy resins comprising a difunctional glycidyl ether epoxy resin, an unmodified BPA-based epoxy resin, a multifunctional epoxidized polybutadiene resin, or any combination thereof. [Embodiment 16] 16. The two-part system of any one of the preceding embodiments, comprising one or more flexible epoxy resins present in an amount of about 10% to about 45% by weight. [Embodiment 17] 17. The two-part system of any one of the preceding embodiments, comprising one or more aliphatic multifunctional epoxy resins comprising epoxidized sorbitol. [Embodiment 18] 18. The two-part system of any one of the preceding embodiments, comprising one or more aliphatic multifunctional epoxy resins present in an amount from about 2% to about 16% by weight. [Embodiment 19] 19. The two-part system of any one of the preceding embodiments, comprising one or more reactive diluents comprising polyglycol diglycidyl ether, trimethylolethane triglycidyl ether, or both. [Embodiment 20] 20. The two-part system of any one of the preceding embodiments, comprising one or more reactive diluents present in an amount from about 5% to about 25% by weight. [Embodiment 21] 21. The two-part system of any one of embodiments 1 to 20, wherein the reaction temperature is from about 10° C. to about 35° C. [Embodiment 22] 22. The two-part system of any one of the preceding embodiments, wherein the reaction temperature is from about 15° C. to about 25° C. [Embodiment 23] 23. The two-part system of any one of the preceding claims, wherein the curing composition has a curing time of about 5 minutes to about 15 minutes. [Embodiment 24] 24. The two-part system of any one of the preceding claims, wherein the curing composition has a cure time of about 7 minutes to about 10 minutes. [Embodiment 25] 25. The two-part system of any one of the preceding claims, wherein the cured composition has a volume expansion of about 100% to about 800%. [Embodiment 26] 26. The two-part system of any one of the preceding claims, wherein the cured composition has a volume expansion of about 400% to about 500%. [Embodiment 27] 27. The two-part system of any one of the preceding claims, wherein the curable composition is dispensed onto a workpiece comprising an automotive part. [Embodiment 28] 28. The two-part system of any one of the preceding claims, wherein the cured composition forms a gasket. [Embodiment 29] 29. The two-part system of any one of the preceding embodiments, wherein the two-part system is free of a curing agent, a cure accelerator, or both. [Embodiment 30] A two-part system, the two-part system comprising: a. a first component, i. one or more liquid epoxy resins; ii. one or more flexible epoxy resins; iii. aliphatic multifunctional epoxy resins; iv. one or more reactive diluents, and v. one or more first component additives; b. a second component, i. a first phosphate ester; ii. a second phosphate ester; iii. an optional third phosphate ester, and iv. a second component comprising one or more second component additives; A two-part system, wherein the first component and the second component, when mixed, form a cured composition at a temperature of from about 0°C to about 50°C. [Embodiment 31] 31. The two-part system of embodiment 30, wherein the first phosphate ester is a phosphate ester derived from cashew nut shell liquid (CNSL). [Embodiment 32]

[0037] Embodiment 32. The two-part system of embodiment 30 or embodiment 31, wherein the second phosphate ester is a 1:1 stoichiometric reaction product of 2-ethylhexylglycidyl to phosphoric acid. [Embodiment 33]

[0037] Embodiment 33. The two-part system of any one of embodiments 30 to 32, wherein the optional third phosphate ester is the reaction product of a stoichiometric ratio of 2-ethylhexylglycidyl to phosphoric acid of 0.8:1. [Embodiment 34]

[0039] Embodiment 34. The two-part system of any one of embodiments 30 to 33, wherein the one or more first component additives comprise one or more of calcium carbonate, minerals, reinforcing fibers, hydrophobic silica, or any combination thereof. [Embodiment 35]

[0037] Embodiment 35. The two-part system of any one of embodiments 30 to 34, wherein the one or more second component additives comprise one or more of a reinforcing fiber, a hydrophobic silica, or both. [Embodiment 36]

[0037] Embodiment 36. The two-part system of any one of embodiments 30 to 35, wherein the one or more liquid epoxy resins comprise a reaction product of epichlorohydrin and bisphenol A. [Embodiment 37]

[0037] Embodiment 37. The two-part system of any one of embodiments 30 to 36, wherein the one or more liquid epoxy resins are present in an amount of about 6% to about 10% by weight. [Embodiment 38]

[0037] Embodiment 38. The two-part system of any one of embodiments 30 to 37, wherein the one or more flexible epoxy resins comprise a difunctional glycidyl ether epoxy resin, an unmodified BPA-based epoxy resin, a multifunctional epoxidized polybutadiene resin, or any combination thereof. [Embodiment 39]

[0037] Embodiment 39. The two-part system of any one of embodiments 30 to 38, wherein the one or more flexible epoxy resins are present in an amount of about 35% to about 45% by weight. [Embodiment 40]

[0041] Embodiment 39. The two-part system of any one of embodiments 30 to 39, wherein the one or more aliphatic multifunctional epoxy resins comprise epoxidized sorbitol. [Embodiment 41] Embodiment 41. The two-part system of any one of Embodiments 30 to 40, wherein the one or more aliphatic multifunctional epoxy resins are present in an amount from about 8% to about 16% by weight. [Embodiment 42]

[0041] Embodiment 42. The two-part system of any one of Embodiments 30 to 41, wherein the one or more reactive diluents comprise polyglycol diglycidyl ether, trimethylolethane triglycidyl ether, or both. [Embodiment 43] Embodiment 43. The two-part system of any one of Embodiments 30 to 42, wherein the one or more reactive diluents are present in an amount from about 8% to about 16% by weight. [Embodiment 44]

[0037] Embodiment 44. The two-part system of any one of embodiments 30 to 43, wherein the reaction temperature is from about 10°C to about 35°C. [Embodiment 45]

[0042] Embodiment 45. The two-part system of any one of embodiments 30 to 44, wherein the reaction temperature is from about 15°C to about 25°C. [Embodiment 46]

[0041] Embodiment 46. The two-part system of any one of embodiments 30 to 45, wherein the curing time of the cured composition is from about 5 minutes to about 15 minutes. [Embodiment 47]

[0042] Embodiment 47. The two-part system of any one of embodiments 30 to 46, wherein the curing composition has a curing time of about 7 minutes to about 10 minutes. [Embodiment 48]

[0041] Embodiment 48. The two-part system of any one of embodiments 30 to 47, wherein the cured composition has a volume expansion of at least about 100% to about 800%. [Embodiment 49]

[0041] Embodiment 49. The two-part system of any one of embodiments 30 to 48, wherein the cured composition has a volume expansion of at least about 400% to about 500%. [Embodiment 50] 50. The two-part system of any one of claims 30 to 49, wherein the curable composition is dispensed onto a workpiece comprising an automotive part. [Embodiment 51]

[0052] The two-part system of any one of claims 30 to 50, wherein the cured composition forms a gasket. [Embodiment 52]

[0047] Embodiment 52. The two-part system of any one of embodiments 30 to 51, wherein the two-part system does not include a curing agent, a cure accelerator, or both. [Embodiment 53] 1. A method, comprising: a. providing a two-part system, the two-part system comprising a first component and a second component, the first component comprising one or more epoxy resins and the second component comprising one or more phosphate esters; b. mixing the first component and the second component to form a reaction product; The method wherein the first component and the second component, upon mixing, form a cured elastomeric composition at a temperature of from about 0°C to about 50°C. [Embodiment 54] 54. The method of embodiment 53, wherein the second component comprises two or three different phosphate esters. [Embodiment 55] 55. The method of embodiment 53 or embodiment 54, wherein the first component comprises one or more first component additives. [Embodiment 56] 56. The method of embodiment 53 or embodiment 55, wherein the second component comprises one or more second component additives. [Embodiment 57] 57. The method of embodiment 53 or embodiment 56, wherein the one or more first component additives comprise calcium carbonate. [Embodiment 58] 58. The method of embodiment 53 or embodiment 57, wherein curing occurs at a temperature of from about 10° C. to about 35° C. [Embodiment 59] 59. The method of embodiment 53 or embodiment 58, wherein curing occurs at a temperature of about 15°C to about 25°C. [Embodiment 60] 60. The method of claim 53 or claim 59, wherein the curing time of the cured composition is from about 5 minutes to about 15 minutes. [Embodiment 61] 61. The method of claim 53 or claim 60, wherein the curing time of the cured composition is from about 7 minutes to about 10 minutes. [Embodiment 62] 62. The method of embodiment 53 or embodiment 61, wherein the cured composition has a volume expansion of about 100% to about 800%. [Embodiment 63] 63. The method of claim 53 or claim 62, wherein the cured composition has a volume expansion of about 400% to about 500%. [Embodiment 64] 64. The method of claim 53 or claim 63, comprising dispensing the curable composition onto a workpiece comprising an automotive part. [Embodiment 65] 65. The method of claim 53 or claim 64, comprising forming a gasket or sealant with the cured composition. [Embodiment 66] 66. The method of embodiment 53 or embodiment 65, wherein the method does not include the addition of a curing agent, a curing accelerator, or both. It is understood that the foregoing description is illustrative and not intended to be limiting. Many embodiments, in addition to the examples provided, and many applications will become apparent to those skilled in the art upon reading the above description. Accordingly, the scope of the present invention should be determined not with reference to the above description, but instead with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and patent publications, are incorporated by reference for all purposes. The omission of any aspect of the subject matter disclosed herein from an appended claim is not a disclaimer of such subject matter, nor should it be construed as a denial by the inventors of such subject matter as part of the disclosed inventive subject matter.

Claims

1. It is a two-part system, a. a first component comprising at least a flexible epoxy resin; b. a second component comprising at least a phosphate ester obtained from the reaction of an epoxide group with phosphoric acid, said phosphate ester being: a first phosphate ester which is a reaction product of a glycidyl ether of cashew nut shell liquid (CNSL) and phosphoric acid; a second phosphate ester which is the reaction product of a 1:1 stoichiometric ratio of 2-ethylhexylglycidyl to phosphoric acid; and a second component comprising a third phosphate ester that is a 0.8:1 stoichiometric reaction product of phosphoric acid and 2-ethylhexyl glycidyl ether; A two-part system, wherein the first component and the second component, when mixed, form an elastomeric curable composition at room temperature.

2. 10. The two-part system of claim 1, wherein the first component comprises one or more first component additives.

3. 3. The two-part system of claim 2, wherein the one or more first component additives comprise one or more of calcium carbonate, minerals, reinforcing fibers, hydrophobic silica, or any combination thereof.

4. 4. The two-part system of claim 1, further comprising calcium carbonate present in an amount of from 1% to 25% by weight of the first component.

5. 5. The two-part system of claim 1, wherein the second component comprises one or more second component additives.

6. 6. The two-part system of claim 5, wherein the one or more second component additives comprise one or more of a mineral, a reinforcing fiber, a hydrophobic silica, or any combination thereof.

7. 7. The two-part system of claim 1, wherein the first component further comprises one or more liquid epoxy resins, one or more aliphatic multifunctional epoxy resins, one or more reactive diluents, or any combination thereof.

8. 8. The two-part system of any one of claims 1 to 7, comprising one or more liquid epoxy resins comprising the reaction product of epichlorohydrin and bisphenol A.

9. 9. The two-part system of claim 1, further comprising one or more liquid epoxy resins present in an amount of from 10% to 30% by weight of the first component.

10. 10. The two-part system of any one of claims 1 to 9, comprising one or more flexible epoxy resins comprising a difunctional glycidyl ether epoxy resin, an unmodified BPA-based epoxy resin, a multifunctional epoxidized polybutadiene resin, or any combination thereof.

11. 11. The two-part system of claim 1, further comprising one or more flexible epoxy resins present in an amount of 10% to 50% by weight of the first component.

12. 12. The two-part system of claim 1, comprising one or more aliphatic multifunctional epoxy resins including epoxidized sorbitol.

13. 13. The two-part system of claim 1, further comprising one or more aliphatic multifunctional epoxy resins present in an amount of 5% to 20% by weight of the first component.

14. 14. The two-part system of any one of claims 1 to 13, comprising one or more reactive diluents comprising polyglycol diglycidyl ether, trimethylolethane triglycidyl ether, or both.

15. 15. The two-part system of any one of claims 1 to 14, including one or more reactive diluents present in an amount of from 5% to 20% by weight of the first component.

16. 16. The two-part system of claim 1, wherein the curing composition has a curing time of 5 to 15 minutes.

17. 17. The two-part system of claim 1, wherein the curing composition has a curing time of 7 to 10 minutes.

18. 18. The two-part system of claim 1, wherein the cured composition has a volume expansion of 100% to 800%.

19. 19. The two-part system of claim 1, wherein the cured composition has a volume expansion of 400% to 500%.

20. 20. The two-part system of any one of claims 1 to 19, wherein the curable composition is dispensed onto a workpiece comprising an automotive part.

21. 21. The two-part system of any one of claims 1 to 20, wherein the cured composition forms a gasket.

22. 22. The two-part system of any one of claims 1 to 21, wherein the two-part system is free of a curing agent, a cure accelerator, or both.

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