Reaction-inducing discoloration composition

Abstract

A two-part system that changes color to indicate proper mixing. The two-part system includes an A side and a B side. Side A and / or Side B includes a reactive color change agent (e.g., a pH sensitive dye). Side B includes one or more acids.

Description

[Technical field]

[0001] The present disclosure relates to two-part systems that include an A-side and a B-side, and in particular to two-part systems that include a reactive color change agent that changes color after mixing of the A-side and the B-side. The two-part system can be advantageous in that it indicates proper mixing, curing, and / or foaming of the A-side and the B-side by changing color. [Background technology]

[0002] Two-part systems are typically supplied as an A-side and a B-side. Two-part systems are typically mixed prior to use. Mixing of the A-side and B-side typically initiates the curing and / or foaming of the system.

[0003] A concern with two-part systems is proper mixing. Two-part systems cannot cure and / or foam properly if not mixed properly. Because they are mixed on-site, extended mechanical mixing with mixing equipment may not be possible. Additionally, mechanical mixing may be prone to static mixer failures or human error. Improper mixing may be detrimental to downstream applications. For example, the reaction product of a two-part system used in a foam molded article may not provide sufficient intended mechanical properties, or if foaming is desired, the reaction product may not have the expansion volume to properly fill spaces. Summary of the Invention [Problem to be solved by the invention]

[0004] It may be desirable to provide an indicator of proper mixing to ensure proper curing and / or foaming of a two-part system.

[0005] It may be desirable to provide a two-part system that exhibits proper mixing.

[0006] It may be desirable to provide a two-part system that provides a simple and clearly understandable indicator of proper mixing.

[0007] It can be desirable to provide a reliable and repeatable measurement of proper mixing.

[0008] It may be desirable to provide a two-part system that includes an indicator that is not expensive.

[0009] It can be desirable to provide a two-part system that exhibits rapid proper mixing.

[0010] It may be desirable to provide a two-part system that includes quality control measures built into the composition. [Means for solving the problem]

[0011] The present disclosure relates to a color-changing two-part system. The color-changing two-part system can address at least some of the needs identified above. The color-changing two-part system may include an A-side and a B-side that includes one or more acids. A non-reactive color changing agent may be present in the A-side and / or the B-side. A reactive color changing agent may be present in the A-side. A non-reactive color changing agent and / or a reactive color changing agent may be present in the two-part system.

[0012] The reactive tarnish may include an aniline derivative. The reactive tarnish may include a 4,4'-methylenedianiline derivative. The reactive tarnish may be epoxidized. The reactive tarnish may be 4,4'-methylenedianiline tetraglycidyl ether.

[0013] The reactive color change agent may be present in the A-side in an amount between about 0.1% and 30% by weight of the A-side, more preferably between about 1% and 25% by weight, and even more preferably between about 5% and 20% by weight of the A-side.

[0014] The non-reactive color change agent may be pH sensitive. The non-reactive color change agent provided on the A side may include cresol red, crystal violet, or both. The non-reactive color change agent provided on the B side may include bromocresol green.

[0015] The non-reactive color change agent may be present in the A-side in an amount between about 0.05% and 5% by weight of the A-side, more preferably between about 0.1% and 3% by weight, and even more preferably between about 1% and 2% by weight.

[0016] The non-reactive color changing agent may be present in the B-side in an amount between about 0.05% and 5% by weight of the B-side, more preferably between about 0.1% and 3% by weight, and even more preferably between about 1% and 2% by weight.

[0017] The A-side may include one or more additional epoxy resins, which may include one or more multifunctional aromatic epoxy resins, multifunctional aliphatic epoxy resins, epoxy novolac resins, silane-modified epoxy resins, or any combination thereof.

[0018] The one or more additional epoxy resins may be present in an amount between about 50% and 80% by weight of the A-side, more preferably between about 55% and 75% by weight, and even more preferably between about 60% and 70% by weight.

[0019] The silane modified epoxy resin may be present in an amount between about 0.5% and 10% by weight of the A-side, more preferably between about 1% and 9% by weight, and even more preferably between about 2% and 8% by weight.

[0020] The epoxy novolac resin may include both one or more liquid epoxy novolac resins and one or more solid epoxy novolac resins.

[0021] The A-side may include one or more additives. The one or more additives may include one or more metal carbonates, minerals, reinforcing fibers, hydrophobic silica, core-shell particle polymers, pigments, or any combination thereof.

[0022] The metal carbonate may include extra fine calcium carbonate, fine calcium carbonate, medium fine calcium carbonate, medium calcium carbonate, coarse calcium carbonate, or any combination thereof. The two-part system, after mixing of the A-side and the B-side, can expand (foam) to a volume of between about 10% and 800%, more preferably between about 50% and 700%, and even more preferably between about 100% and 600% of the initial unexpanded (unfoamed) volume of the A-side and the B-side.

[0023] The A-side may consist essentially of the reactive colour change agent.

[0024] The one or more acids may include at least one or more phosphate esters. The one or more acids may optionally include phosphoric acid, citric acid, acetic acid, other acidic phosphorus compounds, any acid stable to phosphoric acid or phosphate esters, or any combination thereof. The one or more phosphate esters may include phosphate esters derived from cashew nut shell liquid, phosphate esters derived from 2-ethylhexyl glycidyl ether, phosphate esters derived from phenyl glycidyl ether, or any combination thereof.

[0025] The phosphate ester may be present in the B-side in an amount between about 40% and 95% by weight of the B-side, more preferably between about 50% and 80% by weight, and even more preferably between about 60% and about 70% by weight.

[0026] Any phosphoric acid, citric acid, acetic acid, other acidic phosphorus compounds, any acid stable to phosphoric acid or phosphate esters, or any combination thereof may be present in side B in an amount between about 4% and 18% by weight of side B, more preferably between about 6% and 16% by weight, and even more preferably between about 8% and about 14% by weight.

[0027] The ratio of phosphate ester to reactive color change agent may be between about 85:1 and 2.5:1, more preferably between about 80:1 and 5:1, more preferably between about 70:1 and 10:1, and even more preferably between about 60:1 and 20:1.

[0028] Side B may include one or more additives. The one or more additives may include one or more metal carbonates, minerals, reinforcing fibers, hydrophobic silica, core shell particles polymers, pigments, or any combination thereof.

[0029] The two-part composition may be a thermosetting resin.

[0030] The color of the mixed A-side and B-side is not the color predicted from the mixture of the initial color of the A-side and the initial color of the B-side.

[0031] The teachings herein further relate to a two-part system selected from a two-part adhesive and a two-part sealant, the two-part system comprising an A side and a B side, the A side and the B side being separate from one another, and upon mixing the A side and the B side, the resulting mixture develops a color, shade, or visual indicator different from the A side and the B side, the B side comprising one or more acids, and either (i) the A side comprises a first pH-sensitive dye having at least one functional group selected from the group consisting of epoxy, amino, hydroxyl, methyl, carbonyl, carboxyl, and phosphate, (ii) the A side and / or the B side comprises a second pH-sensitive dye different from the first pH-sensitive dye, preferably without the at least one functional group, or both (i) and (ii). [Brief description of the drawings]

[0032] [Figure 1] Photographs of the samples shown in Table 1. [Diagram 2] 1 is a photograph of a foamed sample. [Diagram 3] FIG. 13 is a graph showing the relationship between time to exotherm peak and percentage of YDM on side A. [Figure 4] FIG. 13 is a graph showing the relationship between exothermic peak temperature and percentage of YDM on side A. [Diagram 5] FIG. 13 is a graph showing the relationship between time to exothermic peak and percentage of H3PO4 on side B. [Figure 6] FIG. 13 is a graph showing the relationship between exothermic peak temperature and percentage of H3PO4 on side B. [Figure 7] FIG. 1 is a graph showing the relationship between lap shear peak stress and percentage of YDM. [Figure 8] FIG. 1 shows photographs of the samples shown in Table 3. [Figure 9] FIG. 1 shows photographs of the samples shown in Table 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The present teachings meet one or more of the above needs with the improved two-part composition described herein. The descriptions and illustrations provided herein are intended to convey the teachings, their principles, and their practical application to those skilled in the art. Those skilled in the art can adapt and apply the teachings in their numerous forms, as may be most appropriate for the requirements of a particular use. Thus, the specific embodiments of the present teachings as shown are not intended to be exhaustive or limiting of the present teachings. Thus, the scope of the present teachings should be determined without reference to the description herein, 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 papers and references, including patent applications and patent publications, are incorporated by reference for all purposes. Other combinations are also possible, as can be derived from the following claims, which are also incorporated by reference into this specification.

[0034] This application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 273,598, filed October 29, 2021, the contents of which are fully incorporated herein in their entirety for all purposes.

[0035] WO 2020 / 101732 A1, WO 2020 / 205355 A1, WO 2020 / 206346 A1, and WO 2020 / 198139 describe the use of phosphoric acid and phosphoric acid esters for compositions that cure in place. These compositions are typically used in a wide range of room temperature activated systems, such as rigid foam moldings, cavity fills, gaskets, and sealants. The benefits of such compositions may include the ability to adhere to a variety of substrates, low volatile organic compounds (VOCs), insensitivity to dispensing temperature, insensitivity to the exact mix ratio of the two-part system, the ability to tailor physical and mechanical properties, or any combination thereof. These compositions do not provide an indicator of proper mixing and therefore proper curing and / or foaming.

[0036] The compositions of the present teachings can be two-part compositions ("two-part systems"). The two-part systems can include an A-side and a B-side. The A-side and the B-side can be mixed to form a mixed composition. The mixed composition can be cured to form a reaction product. The reaction product can be fully cured (i.e., does not undergo further crosslinking reactions). Curing can be initiated after mixing the A-side and the B-side. Curing can generally be initiated immediately after mixing the A-side and the B-side. Curing can be delayed for a period of time after mixing the A-side and the B-side. The two-part systems can be free of latent curing agents, cure accelerators, or both.

[0037] The two-part system may be mixed at a temperature of about 0° C. to about 50° C. Curing of the two-part system may be activated at room temperature (i.e., about 18° C. to about 25° C.). If desired, volume expansion may increase as the temperature of the mixed composition and / or the temperature of the A-side and / or B-side during mixing increases. Ambient temperature may not affect the rate of expansion to the same extent as the temperature of the two-part system at the time of dispensing. Ambient temperature, as referred to herein, may mean the temperature of the environment in which the two-part system resides.

[0038] The two-part system may form a thermoset.

[0039] The two-part system may be used in automotive, aerospace, construction, repair shops, home maintenance, other similar industries, or any combination thereof. The two-part system may be used as an adhesive, a composite matrix resin, a foam molding, a cavity filler, a structural reinforcement, an encapsulant, or any combination thereof. The adhesive may bond to similar and / or dissimilar substrates.

[0040] The two-part composition system of the present teachings may be dispensed. Dispensing may be performed by a dispensing device. Dispensing may be performed by an automated or non-automated dispensing device. Dispensing may be performed by a pneumatic or manual system. The two-part composition may be mixed manually without the use of a cartridge or a dispensing device. The manually mixed two-part composition may be poured onto a substrate or into a cavity.

[0041] A side The A-side may include one or more reactive and / or non-reactive colorants, additional epoxy resins (i.e., chemical compositions having one or more reactive epoxy groups), reactive diluents, additives, or any combination thereof. The reactive diluents and / or additives may be optional. The A-side may consist essentially of one or more reactive and / or non-reactive colorants.

[0042] The reactive color change agent may be a material that is pH sensitive such that a color change occurs in response to a change in pH of the environment in which the material is placed. The reactive color change agent may be a pH sensitive dye. The reactive color change agent may include aniline and / or derivatives selected from chloroaniline, methylaniline, and chloromethylaniline. The aniline derivatives may be selected from N-methylaniline, 2,5-dimethoxyaniline, 2-acetyl-phenothiazine, 3-chloro-2-methylaniline, 3-chloro-4-methylaniline, 3-chloroaniline, 4-chloro-3-aminobenzotrifluoride, 5-chloro-2-aminobenzotrifluoride, 5-chloro-2-methylaniline, chloroaniline, chlorodimethoxyaniline, dehydrothiotoluidine, dichloroaniline, dimethylaniline, metatoluidine, o-chloro-p-nitroaniline, paratoluidine, phenothiazine, or phenylenediamine. The aniline may include methylenedianiline (MDA) and / or derivatives thereof. The reactive tarnish may be epoxidized. The reactive tarnish may react to become part of the curing system. Retardation of polymerization, retardation of foaming activation, improved adhesion of the two-part composition to the substrate, or any combination thereof, may result from epoxidation of the reactive tarnish. The reactive tarnish may include 4,4'-methylenedianiline tetraglycidyl ether as shown below.

[0043] [ka]

[0044] The non-reactive color change agent may be present in the A-side. Non-reactive, as referred to herein, may mean that the material does not undergo or contribute to a polymerization reaction. That is, the non-reactive color change agent cannot become part of the polymer chain resulting from the mixing of the A-side and the B-side. The non-reactive color change agent may be pH sensitive. The color of the non-reactive color change agent may depend on the pH of the mixture. The color of the non-reactive color change agent may change as the pH changes. The pH of the A-side according to the present disclosure may be about 5 to 10. The pH of the B-side may be less than 7 or even less than 5. The pH of the combined A-side and B-side may be lower than the pH of the A-side alone due to the acidic component of the B-side. The pH of the combined A-side and B-side may be less than 8, less than 7, or even less than 5. The particular non-reactive color change agent selected may depend on the pH of the A-side prior to mixing with the B-side, as well as the pH of the combined A-side and B-side.

[0045] Reactive and non-reactive color change agents may be collectively referred to herein as "color change agents."

[0046] Any suitable non-reactive color change agent may be used in the disclosed system provided that it is compatible with the A-side chemistry, changes color as the pH drops from the initial pH range of the A-side, and the color transition pH of the non-reactive color change agent is coordinated with the pH change from the A-side to the final product (i.e., the mixed A-side and B-side). Non-reactive color change agents may include, but are not limited to, cresol red, crystal violet, and the like, or any combination thereof.

[0047] The non-reactive color change agent may be present in the A-side in an amount of about 0.05% or more, 1% or more, or even up to 2% or more by weight of the A-side. The non-reactive color change agent may be present in the A-side in an amount of about 5% or less, 4% or less, or even up to 3% or less by weight of the A-side.

[0048] The reactive and / or non-reactive color change agents can change color upon mixing of the A-side and the B-side. The color change can generally be activated immediately after sufficient mixing of the A-side and the B-side. That is, the color change can be activated about 3 minutes or less after mixing, more preferably about 1 minute or less after mixing, more preferably about 30 seconds or less after mixing, and even more preferably about 5 seconds or less after mixing. The color change can be delayed for a period of time after mixing the A-side and the B-side. The delay time can be for about 5 minutes or more, 10 minutes or more, or even 20 minutes or more. The delay time can be for about 2 hours or less, 1 hour or less, or even 30 minutes or less. The A-side and the B-side can be mixed upon dispensing. As an example, the A-side and the B-side can emerge from a static mixer. The color change can provide a visual confirmation of the quality of the mixing and curing.

[0049] The color change may occur when the A-side and B-side are thoroughly mixed. The color change may remain stable after curing, i.e., the hue, saturation, and / or color value of the reaction product may not change appreciably over time (e.g., the color does not change by more than 5% in wavelength) when the reaction product is stored below about 150° C., more preferably below 120° C., even more preferably below 100° C., and / or in an environment without UV exposure.

[0050] Hue, as referred to herein, can mean a primary color (red, green, blue), a secondary color (cyan, magenta, yellow), or any combination thereof. For example, the reaction product may be blue in color or hue.

[0051] Saturation, as referred to herein, can mean color purity, with one end of the saturation range being white and the other end of the saturation being pure hues.

[0052] Color value, as referred to herein, can mean the lightness or darkness of a hue, with one end of the color value range being black and the other end of the color value range being the absence of black.

[0053] A color may be defined by a hue, a saturation, and a color value.

[0054] Side A can have a natural initial color prior to mixing with side B. The natural color may be tan or white if it does not contain any pigments. Side B can have a natural initial color prior to mixing with side A. The natural color may be brown. The mixed composition and / or reaction product can have a color that is different from the color of side A and / or side B. The mixed composition and / or reaction product can have an unexpected color. For example, a mixture of two tan components may be predicted to be tan but may actually be blue.

[0055] The color of the mixed composition and / or reaction product may be blue, dark blue, tan, gray, or yellow. These colors are provided by the exemplary formulations shown herein, but other colors are within the scope of the present teachings. The color of the mixed composition and / or reaction product may be stable at room temperature (i.e., about 18° C. to about 25° C.). The color of the mixed composition and / or reaction product may be darker at elevated temperatures. This is because the color value of the mixed composition and / or reaction product may change at elevated temperatures. The degree of color change may be a function of temperature. As an example, the color may change to light brown, brown, or even dark brown. The color change of a material exposed to a particular elevated temperature may be stable unless and until the material is exposed to a higher temperature.

[0056] The mixed composition can have a color that changes over time until a reaction product is formed. The mixed composition can have a color that changes until a certain degree of curing is achieved. The color change can stop when the mixed composition is about 60% or more, 70% or more, 80% or more, or even 90% or more cured.

[0057] The reactive color change agent and / or the non-reactive color change agent may be used with or without a pigment. The pigment may be provided on the A side, the B side, or both. The pigment may be different from the reactive color change agent. The reactive color change agent may perform its intended indicator function even when the pigment is present. The reactive color change agent may be selected and provided in an amount sufficient to provide a desired final color in conjunction with the pigment. By way of example, the reactive color change agent may be selected and used in an amount to provide a reaction product of a particular hue, saturation, and color value, and the pigment may be selected and used in an amount to improve the hue, saturation, and / or color value of the reaction product. For example, for a blue reaction product, a red pigment may be added to produce a purple reaction product. The pigment may include a white pigment. The white pigment may improve the color saturation of the reaction product. The reactive color change agent may be selected and provided in an amount sufficient to achieve a desired color of the reaction product without the inclusion of a pigment.

[0058] The final color may not be the color predicted upon mixing of the two colors, side A and side B. For example, one would predict that the final color of a white side A and a brown side B would produce a tan mixed composition or reaction product, but the mixed composition or reaction product of the present teachings may be blue. The unexpected color may be particularly advantageous in helping the user determine whether proper mixing has occurred. As an example, some people may not be able to notice subtle color changes, so a brown to yellow color change may be easier for some people to notice compared to a brown to a slightly different hue of brown.

[0059] If the natural (initial) color of the A-side and / or B-side remains generally unchanged, the user can determine that proper mixing, curing, and / or foaming did not occur. The natural color of the A-side and / or B-side may be present as areas or lines in the reaction product. If the reaction product or a portion thereof does not have a predetermined color, the user can determine that proper mixing, curing, and / or foaming did not occur. For example, a color change may occur, but the hue, saturation, and / or color value may differ from the desired hue, saturation, and / or color value of the reaction product.

[0060] The reactive color change agent can provide identification of unmixed or under mixed reaction products or even parts of reaction products. For example, a static mixer may not have the necessary number of mixing elements to properly mix a two-part system. As another example, one of the A or B sides may surge into the static mixer before the other. This is especially likely with a full cartridge set and the first material dispensed from the static mixer nozzle. This can be due to different viscosities of the two components, air pockets in the dispenser, a faulty static mixer, a broken static mixer, or any combination thereof.

[0061] The B side may include an acid, as discussed herein. The epoxidized aniline ring of the reactive discolorant may open upon reaction with an acid. The acid may protonate the aniline group. Without intending to be bound by theory, protonation of the aniline group may be the reason for the reduction in crosslink density and discoloration.

[0062] Ionization of the non-reactive color change agent can be caused by the acid on side B. The ionization can cause the non-reactive color change agent to change color.

[0063] The opening of the epoxy ring, the protonation of the aniline group, and / or the change in pH can be accomplished with an acid, such as phosphoric acid, citric acid, acetic acid, other acidic phosphorus compounds, any acid stable to phosphoric acid or phosphate esters, or any combination thereof. Other acids are contemplated by this disclosure.

[0064] The reactive color change agent may be present in an amount of about 0.1% or more, 1% or more, 5% or more, or even up to 10% or more by weight of side A. The reactive color change agent may be present in an amount of about 30% or less, 25% or less, 20% or less, or even up to 15% or less by weight of side A. The saturation of the color produced by the reactive color change agent may be increased by increasing the amount of reactive color change agent on side A.

[0065] The reactive color change agent may not appreciably affect the foaming of the mixed composition when the amount of reactive color change agent in side A is less than 8%. That is, when the amount of reactive color change agent in side A is less than 8%, the difference in volume expansion of the mixed composition may be about 10% or less, more preferably about 5% or less, and even more preferably about 1% or less, compared to a mixed composition without the reactive color change agent.

[0066] The reactive color change agent may function to indicate proper mixing, improve the ductility of the composition, retard polymerization, retard foaming activation, improve adhesion of the two-part composition to the substrate, or any combination thereof. The reactive color change agent may provide other useful and tunable properties.

[0067] The reactive discolorant can improve the ductility and / or strain to break of the composition. Without intending to be bound by theory, this may be due to a change in the crosslink density and open to closed cell ratio of the foam. The improvement in ductility may depend on the amount of reactive discolorant provided to the A-side.

[0068] Without intending to be bound by theory, the use of reactive color modifiers can increase the pH of the A-side, and thereby the pH of the mixed composition upon mixing of the A-side and B-side. The decrease in acidity can result in a decrease in crosslink density of the final product and / or a decrease in reaction rate. The peak temperature of the exothermic reaction can indicate the degree of crosslink density; i.e., crosslinking can generate heat.

[0069] The reactive discolorant can delay cure and / or foam activation, adjust pot life, adjust cure time, or any combination thereof. Without intending to be bound by theory, the reactive discolorant can increase the pH of the A side, so that the mixed composition can have reduced acidity. The activation delay time, pot life, cure time, or any combination thereof can be increased by increasing the amount of reactive discolorant.

[0070] Increased activation delay time, increased pot time, increased cure time, or any combination thereof may be advantageous for certain applications where the user requires longer assembly time.

[0071] Delayed activation can mean increased open time. Open time can refer to the time before significant curing reaction occurs. The delay time of cure activation of two-part systems can be about 1 minute or more, 5 minutes or more, 10 minutes or more, or even 30 minutes or more. The delay time of cure activation of two-part systems can be about 4 hours or less, 3 hours or less, 2 hours or less, or even 1 hour or less. The delay can be particularly useful in non-foaming compositions that tend to cure faster.

[0072] The open time can increase as the ratio of reactive color change agent in the formulation increases. The open time can decrease as the viscosity of the dispensed A-side and B-side increases. The open time can decrease as the volume of the dispensed A-side and B-side increases. The open time can decrease as the temperature increases.

[0073] The adhesion of the mixed composition to the substrate may be best during the open time. The wetting of the substrate by the mixed composition may be best during the open time. The adhesion and / or wetting may be demonstrated by lap shear testing. The adhesion and / or wetting may be demonstrated by failure mode, particularly a change from adhesive failure mode to cohesive failure mode, or vice versa.

[0074] Pot life can refer to the time it takes for a mixed composition to no longer bond to a substrate.

[0075] Cure time can refer to the time it takes for the mixed composition to completely cure. The peak temperature of the exothermic reaction can indicate the overall cure time. That is, during the composition cure, the composition can experience both heat generation as a result of the exothermic reaction and heat loss by the atmosphere and / or the substrate on which the composition is placed. Thus, a higher peak temperature of the exothermic reaction can indicate a shorter overall cure time, since the exothermic reaction gives more heat to the composition at a faster rate than the heat is dissipated to the atmosphere or the substrate on which the composition is placed. The cure time can be about 1 minute or more, 5 minutes or more, 10 minutes or more, 30 minutes or more, or even 1 hour or more. The cure time can be about 48 hours or less, 24 hours or less, 12 hours or less, 6 hours or less, or even 3 hours or less.

[0076] The reactive discolorant may have an epoxy equivalent weight of about 90 g / eq to 140 g / eq, more preferably 100 g / eq to 130 g / eq, and even more preferably 111 g / eq to 117 g / eq, according to ASTM D1652-11. The reactive discolorant may have a viscosity measured at 25° C. of about 2,000 mPa·s to 8,000 mPa·s, more preferably 2,500 mPa·s to 7,000 mPa·s, and even more preferably 3,000 mPa·s to 6,000 mPa·s, according to ASTM D445-21. Non-limiting examples of suitable reactive discolorants may include Epotec® YDM 441, commercially available from Aditya Birla Chemicals.

[0077] The A-side may include one or more additional epoxy resins. The additional epoxy resins may include a multifunctional aromatic epoxy resin, a multifunctional aliphatic epoxy resin, a silane-modified epoxy resin, an epoxy / elastomer adduct, or any combination thereof.

[0078] The additional epoxy resin may be present in the A-side in an amount of about 50% or more, 55% or more, or even up to 60% or more by weight of the A-side. The additional epoxy resin may be present in the A-side in an amount of about 80% or less, 75% or less, or even up to 70% or less by weight of the A-side.

[0079] The provision of one or more additional epoxy resins in the A-side can slow the reaction time of the composition, thereby increasing the pot life.

[0080] The two-part system may include one or more polyfunctional aromatic and / or aliphatic epoxy resins. The polyfunctional aromatic and / or aliphatic epoxy resins can increase the crosslink density of the reaction product, improve the mechanical properties of the reaction product, improve the chemical resistance of the reaction product, reduce the viscosity of the two-part system and / or the mixed composition, improve the cell structure quality of the foamed reaction product, or any combination thereof. The functionality of the polyfunctional aromatic and / or aliphatic resins can be about 2.1 or more, 3 or more, or even 4 or more. The functionality of the polyfunctional aromatic and / or aliphatic resins can be about 8 or less, 7 or less, or even 6 or less.

[0081] When a two-part system contains a metal carbonate in the A-side, the effective functionality of the B-side may be partially reduced when combined with the A-side in a mixed composition. This may be due to the reaction of the acid in the B-side with the metal carbonate in the A-side to cause foaming. The A-side may contain components of increased functionality to compensate for the reduced functionality of the B-side due to the reaction of the metal carbonate. The A-side may be formulated with increased functionality by using reactive ingredients with a functionality higher than 2, such as aliphatic multifunctional epoxy resins.

[0082] The stiffness of the reaction product may be reduced as a result of including a reactive discolorant in the two-part system. Multifunctional epoxy resins may be used to compensate for the reduced stiffness.

[0083] Examples of suitable multifunctional resins may include, but are not limited to, epoxidized sorbitol, epoxidized soybean oil, solid epoxy novolac resins, liquid epoxy novolac resins, or any combination thereof.

[0084] The multifunctional aliphatic epoxy resin may have an epoxy equivalent weight of about 130 g / eq to 230 g / eq, more preferably about 140 g / eq to 220 g / eq, and even more preferably about 160 g / eq to 195 g / eq, according to ASTM D1652-11. The multifunctional aliphatic epoxy resin may have a viscosity measured at 25°C of about 6,000 mPa·s to about 20,000 mPa·s, more preferably about 7,000 mPa·s to 19,000 mPa·s, and even more preferably about 8,000 mPa·s to 18,000 mPa·s, according to ASTM D445-21. The multifunctional aliphatic epoxy resin may include epoxidized sorbitol. A non-limiting example of a suitable multifunctional aliphatic epoxy resin may include Erisys® GE 60, available from Huntsman Advanced Materials.

[0085] The polyfunctional aromatic epoxy resin may include a reaction product of epichlorohydrin and bisphenol A. The further epoxy resin may be a liquid epoxy resin. The further epoxy resin may have an epoxy equivalent weight of about 160 g / eq to 210 g / eq, more preferably about 170 g / eq to 200 g / eq, even more preferably about 182 g / eq to 192 g / eq, according to ASTM D1652-11. The further epoxy resin may have a viscosity measured at 25° C. of about 9,000 mPa·s to 16,000 mPa·s, more preferably about 10,000 mPa·s to 15,000 mPa·s, even more preferably about 11,000 mPa·s to 14,000 mPa·s, according to ASTM D445-21. Non-limiting examples of suitable difunctional aromatic epoxy resins may include DER™ 331™, available from Olin Corporation.

[0086] The two-part system may include one or more epoxy novolac resins. The epoxy novolac resins may be liquid or solid at room temperature (i.e., about 18° C. to about 25° C.). The two-part system may include one or more liquid epoxy novolac resins, one or more solid epoxy novolac resins, or both. The epoxy novolac resins may have a functionality of about 2.1 to 6.5. The epoxy novolac resins may function to improve the crosslink density, improve the glass transition temperature, improve the mechanical properties, improve the chemical resistance, improve the moisture resistance, or any combination thereof, of the reaction product. Larger amounts of epoxy novolac resins may be used to compensate for some of the possible loss of stiffness (i.e., modulus) that may result from the addition of the reactive tarnish. Higher functionality epoxy novolac resins may be used to improve the stiffness of the composition to compensate for the possible loss of stiffness due to the presence of the reactive tarnish. The choice of epoxy novolac resin may depend on the desired viscosity, mechanical properties, and chemical resistance of the reaction product.

[0087] The epoxy novolac resin(s) may be present in an amount of about 1% or more, 5% or more, 10% or more, or even up to 15% or more by weight of the A-side. The epoxy novolac resin(s) may be present in an amount of about 50% or less, 40% or less, 30% or less, or even up to 20% or less by weight of the A-side.

[0088] The polymeric solid epoxy novolac resin may have an epoxy equivalent weight of about 175 g / eq to 250 g / eq, more preferably about 185 g / eq to 240 g / eq, and even more preferably about 195 g / eq to 230 g / eq, according to ASTM D1652-11. The polymeric solid epoxy novolac resin may have a viscosity measured at 25° C. of about 0.1 Pa·s to 8 Pa·s, more preferably about 0.5 Pa·s to 7 Pa·s, and even more preferably about 1 Pa·s to 6 Pa·s, according to ASTM D445-21. Non-limiting examples of suitable polymeric solid epoxy novolac resins may include Epon™ SU-8, commercially available from Hexion.

[0089] The liquid epoxy novolac resin may have an average functionality of about 1.5 to 4, more preferably 2 to 3.5, more preferably about 2.5 to 3, and even more preferably about 2.65. The liquid epoxy novolac resin may have an epoxy equivalent weight of about 130 g / eq to 200 g / eq, more preferably about 145 g / eq to 185 g / eq, and even more preferably about 165 g / eq to 178 g / eq, according to ASTM D1652-11. The liquid epoxy novolac resin may have a viscosity measured at 25° C. of about 10,000 mPa·s to 40,000 mPa·s, more preferably about 15,000 mPa·s to 30,000 mPa·s, and even more preferably about 18,000 mPa·s to 28,000 mPa·s, according to ASTM D445-21. A non-limiting example of a suitable liquid epoxy novolac resin may include Epalloy® 8250, commercially available from Huntsman Advanced Materials.

[0090] The liquid epoxy novolac resin may be a reaction product of epichlorohydrin and phenol formaldehyde novolac. The epoxy phenol novolac resin may have an epoxy equivalent weight of about 145 g / eq to 195 g / eq, more preferably 155 g / eq to 185 g / eq, and even more preferably 164 g / eq to 177 g / eq, according to ASTM D1652-11. The epoxy phenol novolac resin may have a viscosity measured at 25°C of about 16,000 mPa·s to 25,000 mPa·s, more preferably 17,000 mPa·s to 24,000 mPa·s, and even more preferably 18,000 mPa·s to 23,000 mPa·s, according to ASTM D445-21. A non-limiting example of a suitable liquid epoxy novolac resin may include DEN™ 426, commercially available from Olin Epoxy.

[0091] The two-part system may include one or more silane-modified epoxy resins. The silane-modified epoxy resins may function to impart improved adhesion of the reaction product. The adhesion may be to glass, metal, or both. The silane groups may form covalent bonds with the epoxy resin and the inorganic substrate. The silane-modified epoxy resin may be present on the A-side. The silane-modified epoxy resin may be present in an amount of about 0.5% or more, 1% or more, 2% or more, or even up to about 3% or more by weight of the A-side. The silane-modified epoxy resin may be present in an amount of about 10% or less, 9% or less, 8% or less, or even up to about 7% or less by weight of the A-side.

[0092] The silane-modified epoxy resin may have an epoxy equivalent weight of about 170 g / eq to 240 g / eq, more preferably about 180 g / eq to 230 g / eq, and even more preferably about 190 g / eq to 220 g / eq, according to ASTM D1652-11. The silane-modified epoxy resin may have a viscosity measured at 25° C. of about 7,000 mPa·s to 17,000 mPa·s, more preferably about 8,000 mPa·s to 16,000 mPa·s, and even more preferably about 9,000 mPa·s to 15,000 mPa·s. A non-limiting example of a suitable silane-modified epoxy resin may include Epokukdo KSR 177, commercially available from Kukdo Chemical Co., Ltd.

[0093] The two-part system may include one or more epoxy / elastomer adducts. The epoxy / elastomer adducts may be included to impart a plasticizing effect to the two-part system and / or to improve the structural properties of the two-part system, such as strength, break strain, fracture toughness (G1c), peel, adhesion durability, uncured material integrity (i.e., less likely to stick, break, or deform prior to use), and stiffness. Carboxyl-terminated butadiene-acrylonitrile may be particularly useful for developing adhesion to contaminated surfaces. The contaminated surface may include stamping lubricants typical of the automotive industry.

[0094] The elastomer in the adduct may be selected from polysulfide, polybutadiene, polyisoprene, polyisobutylene, isoprene-butadiene copolymer, neoprene, acrylic, natural rubber, carboxyl-terminated butadiene-acrylonitrile, polysiloxane, polyester, urethane prepolymer, nitrile rubber (e.g., butyl nitrile, e.g., carboxy-terminated butyl nitrile), butyl rubber, polysulfide elastomer, acrylic elastomer, acrylonitrile elastomer, silicone rubber, polyester rubber, diisocyanate-linked condensation elastomer, styrene butadiene rubber, ethylene-propylene diene rubber, chlorosulfonated polyethylene, fluorinated hydrocarbon, or any combination thereof. The epoxy / elastomer adduct may include a carboxyl-terminated polymer (e.g., adducted carboxyl-terminated polymer, adducted carboxy-terminated butyl nitrile). The epoxy / elastomer adduct may be a dicarboxylic acid. The elastomer compound suitable for the adduct may be, but is not required to be, a thermosetting elastomer.

[0095] Examples of further or alternative epoxy / elastomers or other additives suitable for use with the present teachings are disclosed in U.S. Patent Publication No. 2004 / 0204551 A1 and WO 2020 / 033393 A1.

[0096] The adduct itself generally contains about 1:5 to 5:1 parts epoxy to elastomer, more preferably about 1:3 to 3:1 parts epoxy to elastomer. More typically, the adduct contains at least about 10%, more typically at least about 20%, or even at least about 30% elastomer, and typically up to about 60%, although higher or lower percentages are possible.

[0097] The epoxy / elastomer adduct may be present in the A-side. The epoxy / elastomer adduct may be present in an amount of about 1% or more, 5% or more, 10% or more, or even up to 15% or more by weight of the A-side. The epoxy / elastomer adduct may be present in an amount of about 35% or less, 30% or less, 25% or less, or even up to 20% or less by weight of the A-side.

[0098] The epoxy / elastomer adduct may be a combination of two or more different adducts. The adducts may include solid adducts, liquid adducts, or semi-solid adducts at room temperature (i.e., about 18° C. to about 25° C.), or some combination thereof. The adduct may include one or more adducts that are substantially all (i.e., at least 70%, 80%, 90% or more) solid at room temperature.

[0099] The A-side may include one or more additives. The one or more additives may include metal carbonates, minerals, reinforcing fibers, hydrophobic silica, core-shell particle polymers, pigments, or any combination thereof.

[0100] The two-part system may effervescent due to the presence of one or more metal carbonates in the two-part system. The metal carbonate may react with an acid. The metal carbonate may be provided on side A. The acid may be provided on side B. The metal carbonate may include calcium carbonate. The calcium carbonate may be provided in one or more different particle sizes. Many combinations of calcium carbonate particle sizes may be used.

[0101] The metal carbonate can be provided as a combination of fine and medium fine calcium carbonate. The fine calcium carbonate provides a uniform and fine cell structure. The combination of fine and medium fine calcium carbonate can provide a balance between foaming and setting, and thus structural integrity of the foam.

[0102] The reaction product can have a volume expansion of about 10% or more, 50% or more, 100% or more, or even 200% or more. The reaction product can have a volume expansion of about 800% or less, 700% or less, 600% or less, or even 500% or less.

[0103] The color saturation of the reaction product decreases as foaming increases; that is, the color becomes lighter as the reaction product foams to a greater volume expansion. The color change can be used as an indicator to monitor when and whether foaming and curing are complete, and whether acceptable foaming has occurred.

[0104] Foaming can begin before complete curing of the reaction product. The foaming time of the mixed composition can be about 30 seconds or more, 1 minute or more to 5 minutes or more, or even 10 minutes or more. The foaming time of the mixed composition can be about 2 hours or less, 1 hour or less, or even 30 minutes or less. The foaming time can be the time frame during which the two-part system is actively foaming.

[0105] The calcium carbonate may comprise ultrafine particle size calcium carbonate. The ultrafine particle size may be about 1 micron to 3 microns, and even more preferably about 2 microns. A non-limiting example of a suitable ultrafine calcium carbonate may include Hubercarb® Q2, commercially available from Huber Engineered Materials.

[0106] The calcium carbonate may comprise medium fine particle size calcium carbonate. The medium fine particle size may be about 20 microns to 24 microns, and even more preferably about 22 microns. A non-limiting example of a suitable medium fine particle size calcium carbonate may include Hubercarb® Q200, medium fine, available from Huber Engineered Materials.

[0107] The calcium carbonate may comprise a medium fine particle size calcium carbonate. The medium fine particle size may be between about 10 microns and 16 microns, and even more preferably about 13 microns. A non-limiting example of a suitable ultra-fine calcium carbonate may include Hubercarb® Q325, available from Huber Engineered Materials.

[0108] The calcium carbonate may include coarse particle size calcium carbonate. The coarse particle size can be about 200 microns to 800 microns, 300 microns to 700 microns, or even 400 microns to 600 microns. A non-limiting example of a suitable ultra-fine calcium carbonate may include Hubercarb® Q40-200, commercially available from Huber Engineered Materials.

[0109] The minerals may include one or more silicate minerals. The silicate minerals may include one or more inosilicates. The inosilicates may include wollastonite. The wollastonite may improve mechanical strength, durability, adhesion, moisture resistance, impact resistance, or any combination thereof. The individual crystals or crystal clusters of the one or more minerals may be acicular in shape. The wollastonite may include embedded metal carbonates that contribute to effervescence. The acicular structure of the minerals with aspect ratios ranging from 9 to 20 may help improve the mechanical strength and durability of the reaction product. Non-limiting examples of suitable wollastonite may include NYGLOS® 12 and NYGLOS® 8 available from NYCO Minerals Inc., and Vansil® HR 2000 available from Vanderbilt Minerals, LLC.

[0110] Non-limiting examples of suitable hydrophobic silicas may include AEROSIL® R 202, available from Evonik Corporation, and CAB-O-SIL® TS-530 and TS-720, available from Cabot Corporation.

[0111] Organophilic phyllosilicates may be used in place of hydrophobic silica. Examples of suitable organophilic phyllosilicates may include Garamite-1958, available from BYK-Chemie GmbH.

[0112] The two-part system may include one or more core-shell particle polymers. The core-shell particle polymers can function to improve the fracture toughness and ductility of the reaction product. Epoxy resin formulations are usually known for applications that require stiffness and high temperature resistance. Epoxy resins tend to be brittle. There are various strategies to reduce the brittleness of epoxy resins. Often, toughening agents, such as core-shell polymer particles, are used to reduce brittleness and improve the fracture toughness of the reaction product without significantly affecting the temperature resistance.

[0113] The core-shell particle polymer may be present on the A-side, the B-side, or both. The core-shell particle polymer may be present in an amount of about 5% or more, 10% or more, or even up to 15% or more by weight of the A-side or the B-side. The core-shell particle polymer may be present in an amount of about 35% or less, 30% or less, or even up to 25% or less by weight of the A-side or the B-side.

[0114] The core-shell particle polymer may be premixed with the epoxy resin and dispersed in the epoxy resin. The core-shell particle polymer may be dispersed in a bisphenol A type epoxy resin. The epoxy resin may be a liquid epoxy resin. The epoxy resin may have a viscosity measured at 50°C according to ASTM D445-21 of about 16,000 mPa·s to about 20,000 mPa·s, more preferably 17,000 mPa·s to 19,000 mPa·s, even more preferably about 18,000 mPa·s. The core-shell particle polymer may be present in the epoxy resin in an amount of about 30% to 45%, more preferably 35% to 40%, even more preferably about 37%. The core-shell particle polymer may have a median particle size of about 100 nm to 300 nm, or even about 200 nm. The core-shell particle polymer may include polybutadiene. Non-limiting examples of suitable core-shell particle polymers may include Kane Ace MX-257 and MX-267, commercially available from Kaneka Corporation.

[0115] B side The B-side may include one or more acids, acid anhydrides, further epoxy resin reaction products, reactive diluent reaction products, additives, non-reactive discolorants, or any combination thereof. The further epoxy resin reaction products and / or reactive diluent reaction products may be optional. The B-side may consist essentially of one or more acids.

[0116] Side B may include one or more acids. The acid may be liquid at room temperature. Room temperature, as referred to herein, may mean a temperature between about 18°C ​​and about 25°C. The acid may have a pH of less than 7. The acid may include a phosphate ester, phosphoric acid, citric acid, acetic acid, or any combination thereof. The acid may include at least a phosphate ester, and optionally phosphoric acid, citric acid, acetic acid, other acidic phosphorus compounds, any acid stable with phosphoric acid or a phosphate ester, or any combination thereof. An acid stable with phosphoric acid or a phosphate ester may be one that does not affect shelf life when mixed with phosphoric acid or a phosphate ester. The acid may react with a reactive color change agent. The reaction with the reactive color change agent may result in a color change in the mixed composition and the reaction product. The pH of the acid may affect the color of the non-reactive color change agent.

[0117] The acid can contribute to effervescence in a two-liquid system.

[0118] The pot life of the mixed composition can be adjusted by the selection of the acid. Using phosphate esters instead of phosphoric acid can delay the curing reaction due to their higher pH, lower functionality, higher viscosity, or any combination thereof. The functionality and pH of the phosphate esters can be selected to adjust the pot life.

[0119] Side B may include one or more phosphate esters. The phosphate esters may be the reaction product of a monoepoxide (a "phosphate ester precursor") with phosphoric acid, as shown below.

[0120] [ka] [ka] [ka]

[0121] The phosphate ester may include a phosphate ester derived from cashew nut shell liquid (CNSL). The cashew nut shell liquid may be epoxidized. The epoxidized cashew nut shell liquid may be a reaction product of one or more components of cashew nut shell liquid with epichlorohydrin. The one or more components of cashew nut shell liquid may include anacardic acid, cardanol, cardol, or any combination thereof having an aliphatic C10-C20 moiety. The aliphatic C10-C20 moiety may be saturated or unsaturated. The aliphatic C10-C20 moiety may be hydrophobic. The phosphate ester may be a reaction product of the epoxidized cashew nut shell liquid with phosphoric acid as shown below.

[0122] [ka]

[0123] Although cardanol-based cashew nut shell liquid is described above, other components of cashew nut shell liquid are contemplated by this disclosure. A non-limiting example of a suitable epoxidized cashew nut shell liquid may include Cardolite® LITE 2513HP, commercially available from Cardolite Corporation, Monmouth Junction, New Jersey.

[0124] The phosphate ester may include a phosphate ester derived from 2-ethylhexyl glycidyl ether. The phosphate ester may be an isomer of the reaction product of 2-ethylhexyl glycidyl ether and phosphoric acid, as shown below.

[0125] [ka]

[0126] The above reaction can produce an isomer in which the hydroxide group follows the α carbon, and an isomer in which the hydroxide group follows the β carbon.

[0127] A non-limiting example of a suitable 2-ethylhexyl glycidyl ether may include ERISYS® GE-6, commercially available from CVC Thermoset Specialties, Moorestown, New Jersey.

[0128] The phosphate ester may include a phosphate ester derived from a phenyl glycidyl ether. A non-limiting example of a suitable phenyl glycidyl ether may include ERISYS® GE-13, commercially available from CVC Thermoset Specialties, Moorestown, New Jersey.

[0129] Phosphate esters may be produced by reaction of phosphoric acid and / or polyphosphoric acid and / or phosphoric anhydride and / or phosphoryl chloride with various alcohols ("phosphate ester precursors").

[0130] The B-side may include one or more phosphate esters, phosphate ester precursors, or both. The one or more phosphate esters may be pre-reacted. The B-side may include one or more phosphate ester precursors that may be combined with phosphoric acid prior to combination with the A-side.

[0131] The phosphate esters may be produced by reaction of a range of stoichiometric ratios of phosphate ester precursors with phosphoric acid. One or more phosphate esters may be produced by reaction of a ratio of phosphate ester precursors to phosphoric acid of about 0.6:1 to 1:0.6, more preferably about 0.7:1 to 1:0.7, and even more preferably about 0.8:1 to 1:0.8. The phosphate esters may be present in an amount of about 40% or more, 50% or more, or even up to 60% or more by weight of the B side. The phosphate esters may be present in an amount of about 95% or less, 80% or less, or even up to 70% or less by weight of the B side.

[0132] Phosphoric acid, citric acid, acetic acid, other acidic phosphorus compounds, any acid stable with phosphoric acid or phosphate esters, or any combination thereof may be present in the B-side in an amount of about 4% or more, 6% or more, or even 8% or more by weight of the B-side. Phosphoric acid, citric acid, acetic acid, other acidic phosphorus compounds, any acid stable with phosphoric acid or phosphate esters, or any combination thereof may be present in the B-side in an amount of about 18% or less, 16% or less, or even 14% or less by weight of the B-side.

[0133] The B-side may include additional phosphoric acid. The additional phosphoric acid may include orthophosphoric acid, polyphosphoric acid, or both. The additional phosphoric acid may increase crosslink density and decrease open time. The reaction rate of the pre-reacted phosphate ester may be increased by the addition of additional phosphoric acid to the B-side. The additional phosphoric acid may increase the foaming rate and total foam volume of the mixed composition.

[0134] The ratio of phosphate ester to reactive color change agent may be between about 85:1 and 2.5:1, more preferably between about 80:1 and 5:1, more preferably between about 70:1 and 10:1, and even more preferably between about 60:1 and 20:1.

[0135] The ratio of phosphoric acid, citric acid, acetic acid, other acidic phosphorus compounds, any acid stable to phosphoric acid or phosphate esters, or any combination thereof, to the reactive color change agent may be between about 0.1:1 and 5:1, more preferably between about 0.5:1 and 4:1, and even more preferably between about 1:1 and 3:1.

[0136] A non-reactive color change agent may be present in the B-side. Non-reactive, as referred to herein, may mean that the material does not undergo or contribute to a polymerization reaction. That is, the non-reactive color change agent cannot become part of the polymer chain resulting from the mixing of the A-side and the B-side. The non-reactive color change agent may be pH sensitive. The color of the non-reactive color change agent may depend on the pH of the mixture. The pH of the B-side according to the present disclosure may be about 1-4. The pH of the combined A-side and B-side may be higher than the pH of the B-side alone due to the relatively high pH of the A-side. The particular non-reactive color change agent selected may depend on the pH of the B-side prior to mixing with the A-side, as well as the pH of the combined A-side and B-side.

[0137] Any suitable non-reactive color change agent may be used in the disclosed system provided that it is compatible with the chemistry of the B-side, changes color as the pH increases from the initial pH range of the B-side, and the color transition pH of the non-reactive color change agent is coordinated with the pH change from the B-side to the final product (i.e., the mixed A-side and B-side). Non-reactive color change agents may include, but are not limited to, bromocresol green, and the like, or any combination thereof.

[0138] The non-reactive color change agent may be present in the B-side in an amount of about 0.05% or more, 1% or more, or even up to 2% or more by weight of the B-side. The non-reactive color change agent may be present in the B-side in an amount of about 5% or less, 4% or less, or even up to 3% by weight of the B-side.

[0139] Side B may include one or more additives. The one or more additives may include minerals, reinforcing fibers, hydrophobic silica, core shell particles polymers, pigments, or any combination thereof.

[0140] The mineral may include wollastonite. Non-limiting examples of suitable wollastonite may include NYGLOS® 12 and NYGLOS® 8 available from NYCO Minerals Inc., and Vansil® HR2000 available from Vanderbilt Minerals, LLC.

[0141] Non-limiting examples of suitable hydrophobic silicas may include AEROSIL® R 202, available from Evonik Corporation, and CAB-O-SIL® TS-530 and TS-720, available from Cabot Corporation.

[0142] Organophilic phyllosilicates may be used in place of hydrophobic silica. Examples of suitable organophilic phyllosilicates may include Garamite-1958, available from BYK-Chemie GmbH.

[0143] The two-part system may include one or more core-shell particle polymers. The core-shell particle polymers can function to improve the fracture toughness and ductility of the reaction product. Epoxy resin formulations are usually known for applications that require stiffness and high temperature resistance. Epoxy resins tend to be brittle. There are various strategies to reduce the brittleness of epoxy resins. Often, toughening agents, such as core-shell polymer particles, are used to reduce brittleness and improve the ductility of the reaction product without significantly affecting the temperature resistance.

[0144] The core-shell particle polymer may be present on the A-side, the B-side, or both. The core-shell particle polymer may be present in an amount of about 5% or more, 10% or more, or even up to 15% or more by weight of the A-side or the B-side. The core-shell particle polymer may be present in an amount of about 35% or less, 30% or less, or even up to 25% or less by weight of the A-side or the B-side.

[0145] The core-shell particle polymer may be premixed with the epoxy resin and dispersed in the epoxy resin. In this case, the core-shell particle polymer may be used in the A-side. The core-shell particle polymer may be dispersed in a bisphenol A type epoxy resin. The epoxy resin may be a liquid epoxy resin. The epoxy resin may have a viscosity measured at 50°C according to ASTM D445-21 of about 16,000 mPa·s to about 20,000 mPa·s, more preferably 17,000 mPa·s to 19,000 mPa·s, even more preferably about 18,000 mPa·s. The core-shell particle polymer may be present in the epoxy resin in an amount of about 30% to 45%, more preferably 35% to 40%, even more preferably about 37%. The core-shell particle polymer may have a median particle size of about 100 nm to 300 nm, or even about 200 nm. The core-shell particle polymer may include polybutadiene. Non-limiting examples of suitable core-shell particle polymers may include Kane Ace MX-257 and MX-267, commercially available from Kaneka Corporation.

[0146] The two-part composition may be mixed in a volume ratio of side A to side B. The volume ratio of side A to side B may be from about 10:1 to 1:1, and even more preferably from about 5:1 to 2:1. EXAMPLES

[0147] FIG. 1 illustrates the formation of unexpected colors upon mixing of sides A and B based on the initial colors of sides A and B. In column A, side A (left) is white and side B (right) is brown, and mixing of the two results in a blue reaction product. At least one predicted color produced from the white and brown may be a tan color. In column B, side A (left) is magenta and side B (right) is brown, and mixing of the two results in a purple reaction product. At least one predicted color produced from the magenta and brown may be a crimson color. In column C, side A (left) is yellow and side B (right) is brown, and mixing of the two results in a green reaction product. At least one predicted color produced from the yellow and brown may be a lighter shade of brown.

[0148] FIG. 2 illustrates the lightening of color (decrease in chroma) produced by the increasing volume expansion produced by foaming. The mixed composition is blue in color, and the lighter shade of blue is due to the increasing expansion volume. A dashed reference line is provided to better illustrate the volume expansion. From left to right, the composition expands (foams) to increasing volume expansion. Each sample contains the same amount of reactive color change agent.

[0149] Table 1 shows various formulations with different ratios of reactive color change agent, Epotec® YDM 441. Ratios can be between the reactive color change agent and the set of other ingredients on side A. All amounts are given in grams.

[0150] [Table 1]

[0151] Figure 3 shows a graph showing the relationship of the time it takes for the formulations of Table 1 to reach a peak exothermic temperature as a function of the ratio of reactive discolorant in the A-side formulation. The time it takes to reach a peak exothermic temperature generally increases as the ratio of reactive discolorant in the A-side formulation increases. The peak exothermic temperature was determined in accordance with ASTM D2471-99.

[0152] Figure 4 shows a graph. The graph shows the relationship between the ratio of reactive discolorant on the A-side of the formulations in Table 1 and the peak exothermic reaction temperature. As the ratio of reactive discolorant on the A-side increases, the peak exothermic reaction temperature generally decreases. The peak exothermic reaction temperature was determined in accordance with ASTM D2471-99.

[0153] Table 2 shows various formulations with different ratios of phosphoric acid on the B side. The ratios can be between phosphoric acid and a collection of other ingredients on the B side. The ratio of reactive tarnish present on the A side is constant. Increasing the amount of phosphoric acid (H3PO4) can compensate for the reduction in crosslink density due to the presence of reactive tarnish in the formulation. Increasing the amount of phosphoric acid can improve the mechanical properties of the reaction product while maintaining a longer delay time of cure activation and / or overall cure time. All amounts are given in grams.

[0154] [Table 2]

[0155] FIG. 5 shows a graph showing the time taken to reach the peak temperature of the exothermic curing reaction as a function of the ratio of phosphoric acid in the B-side formulation. The time taken to reach the peak temperature of the exothermic reaction generally decreases as the ratio of phosphoric acid in the B-side increases. The peak temperature of the exothermic reaction was determined in accordance with ASTM D2471-99.

[0156] FIG. 6 shows a graph showing the peak exothermic reaction temperature as a function of the ratio of phosphoric acid in the B-side formulation. As the ratio of phosphoric acid in the B-side increases, the peak exothermic reaction temperature generally increases. The peak exothermic reaction temperature was determined in accordance with ASTM D2471-99.

[0157] Figure 7 shows a graph. The graph shows the lap shear peak stress as a function of the ratio of reactive color change in the formulation. As the ratio of reactive color change increases, the lap shear peak stress generally increases. Lap shear testing can be performed according to ASTM D3163-01.

[0158] Figure 8 shows the reaction product exposed to various temperatures. The reaction product was exposed to a particular temperature for approximately 30 minutes. The light blue color of the reaction product cures at room temperature and changes slightly when post cured at approximately 121°C. The color of the material changes to light brown when exposed to 149°C. The color of the material changes from light brown to brown at approximately 117°C. The color of the material changes from brown to dark brown at approximately 204°C. The color of the material can change from dark brown to dark brown / black at approximately 232°C.

[0159] The intensity of the color change at high temperatures may depend on the ratio of reactive color change agents on side A. Table 3 shows the formulation of the reaction products illustrated in FIG.

[0160] [Table 3]

[0161] Table 4 shows an example formulation where a small amount of non-reactive color change agent is used. The non-reactive color change agent is pH sensitive. The non-reactive color change agent can change the color of the A-side and B-side mixture. All amounts are given in grams.

[0162] [Table 4]

[0163] Figure 9 shows the color changing effect of including a non-reactive color change agent in a two-part system. Sides A and B are shown in the top row. The color of the unmixed A and B sides is the same for samples L, M, and N. Side A is tan and side B is brown. A small amount of non-reactive color change agent added to each sample according to Table 4 results in little change to the initial color of sides A and B.

[0164] The mixed A-side and B-side products for each sample are shown in the columns below. The mixed product colors differ as a result of the non-reactive color change agent provided and the pH change caused by mixing the A-side and B-side. Sample L turned pink, Sample M turned light blue / gray, and Sample N turned yellow. None of these colors were expected from the combination of tan material (A-side) and brown material (B-side).

[0165] It is understood that the above description is intended to be illustrative and not limiting. In addition to the examples provided, many embodiments and many applications will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present invention should not be determined 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 papers and references, including patent applications and patent publications, are incorporated by reference for all purposes. The omission in the following claims of any aspect of the subject matter disclosed herein should not be considered as a disclaimer of such subject matter, nor should it be deemed that the inventors did not consider such subject matter to be part of the subject matter of the disclosed invention.

[0166] The descriptions and illustrations set forth herein are intended to convey to one skilled in the art the invention, its principles, and its practical application. The above description is intended to be illustrative and not limiting. Those skilled in the art can adapt and apply the invention in its numerous forms, as may be most suitable to the requirements of a particular use.

[0167] Thus, the specific embodiments of the present invention as illustrated are not intended as being exhaustive or limiting of the present teachings. Accordingly, the scope of the present teachings should be determined not with reference to this description, but instead with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The omission in the following claims of any aspect of subject matter disclosed herein should not be construed as a disclaimer of such subject matter, nor as a failure by the inventors to consider such subject matter as part of the disclosed inventive subject matter.

[0168] Several components or steps may be provided by one integrated component or step. Alternatively, one component or step may be separated into several separate components or steps.

[0169] The disclosure of "a" or "one" to refer to an element or step is not intended to exclude additional elements or steps.

[0170] The term "generally" or "substantially" to refer to an angular measurement can mean about + / -10° or less, about + / -5° or less, or even about + / -1° or less. The term "generally" or "substantially" to refer to an angular measurement can mean about + / -0.01° or more, about + / -0.1° or more, or even about + / -0.5° or more. The term "generally" or "substantially" to refer to a linear measurement, percentage, or ratio can mean about + / -10% or less, about + / -5% or less, or even about + / -1% or less. The term "generally" or "substantially" to refer to a linear measurement, percentage, or ratio can mean about + / -0.01% or more, about + / -0.1% or more, or even about + / -0.5% or more.

[0171] Unless otherwise indicated, 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 endpoints of that range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30," inclusive of at least the specified endpoint.

[0172] Unless otherwise indicated, any numerical value set forth herein includes all values ​​from the lower limit to the upper limit in increments of one unit, provided that any lower limit and any upper limit are separated by at least two units. By way of example, if an amount of an ingredient, property, or process value that varies, such as temperature, pressure, time, etc., is set forth as, for example, 1-90, 20-80, or 30-70, intermediate range values ​​such as (e.g., 15-85, 22-68, 43-51, 30-32, etc.) are intended to be within the teachings of this specification. Similarly, each intermediate value is 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, as appropriate. These are merely examples of what is specifically intended, and all possible combinations of numerical values ​​between the recited lower and upper limits are considered to be expressly set forth in this application in a similar manner. Unless otherwise indicated, all ranges include both endpoints and all numbers between the endpoints.

[0173] Thus, any teaching of an amount expressed as "parts by weight" herein also contemplates the same range expressed in terms of weight percent. Thus, any expression of a range for "at least 'x' parts by weight of the resulting composition" also contemplates the teaching of that same indicated amount range of "x" in weight percent of the resulting composition.

[0174] The term "consisting essentially of" to describe a combination should include the specified components, ingredients, components, or steps, as well as such other components, ingredients, components, or steps that do not materially affect the underlying novel properties of the combination. Use of the terms "comprising" or "including" herein to describe a combination of components, ingredients, components, or steps also contemplates embodiments that consist essentially of that component, ingredient, component, or step.

[0175] The disclosures of all articles and references, including patent applications and patent publications, are incorporated by reference for all purposes. Other combinations are also possible, as can be obtained from the following claims, which are also incorporated by reference into this specification.

Claims

1. In a two-component discoloration system, Side A and and a B-side comprising one or more acids; A two-part system in which a reactive color change agent is present in the A-side, a non-reactive color change agent is present in the A-side and / or the B-side, or both.

2. 10. The two-part system of claim 1, wherein the reactive color change agent comprises an aniline derivative selected from chloroaniline, methylaniline, and chloromethylaniline.

3. The two-part system of claim 1 or claim 2, wherein the reactive color change agent comprises a 4,4'-methylenedianiline derivative.

4. 3. The two-part system of claim 1 or claim 2, wherein the reactive color modifier is epoxidized such that reactivity is based on epoxy functionality.

5. The two-part system of claim 4, wherein the reactive color change agent is 4,4'-methylenedianiline tetraglycidyl ether.

6. 3. The two-part system of claim 1 or claim 2, wherein the reactive color change agent is present in the A-side in an amount of between about 0.1% and 30% by weight of the A-side, more preferably between about 1% and 25% by weight, and even more preferably between about 5% and 20% by weight.

7. 3. The two-component system of claim 1 or claim 2, wherein the color change process is pH sensitive.

8. 3. The two-part system of claim 1 or claim 2, wherein the non-reactive color changing agent provided on the A-side comprises cresol red, crystal violet, or both.

9. 3. The two-part system of claim 1 or claim 2, wherein the non-reactive color changing agent is present in the A-side in an amount between about 0.05% and 5% by weight of the A-side, more preferably between about 0.1% and 3% by weight, and even more preferably between about 1% and 2% by weight.

10. 3. The two-part system of claim 1 or claim 2, wherein the non-reactive color changing agent provided on the B-side comprises bromocresol green.

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