Toughening agents with enhanced modulus retention

Abstract

A solid epoxy resin adduct comprising the reaction product of a solid carboxylated nitrile rubber (XNBR) and at least one epoxy functional resin.

Description

[0001] Priority Statement

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 525,598, filed on July 7, 2023, the contents of which are incorporated herein by reference in their entirety and for all purposes. Technical Field

[0003] This teaching generally relates to solid carboxylated nitrile butadiene rubber-epoxy resin adducts, which can be used as toughening agents in epoxy resin-based compositions to improve modulus retention at high temperatures. Background Technology

[0004] For many years, industry, especially the transportation sector, has focused on sound attenuation, adhesion, and reinforcement in manufactured goods such as motor vehicles. To this end, industry has developed a variety of materials to provide this sound insulation, adhesion, and reinforcement. For adhesion and reinforcement materials, some desirable properties include high tensile modulus, high failure strain, and adhesion durability.

[0005] Epoxy thermosetting plastics formulated with liquid carboxyl-terminated nitrile butadiene rubber (CTBN) containing toughening agents are materials that meet most requirements. During curing, most of the CTBN reagent becomes incompatible with the curing epoxy resin and forms individual low glass transition temperature (Tg) elastomer microdomains, which improve the fracture toughness of the cured thermosetting material. The unseparated portions of the CTBN material are bonded to the continuous epoxy matrix. This results in a decrease in modulus or Tg due to the presence of low-Tg elastomer material in the matrix. When properly formulated, these thermosetting materials offer a reasonable balance of properties such as adhesion, tensile modulus, failure strain, peel strength, and fracture toughness at room temperature.

[0006] A persistent challenge for these materials is their ability to maintain performance at high temperatures. Methods to increase the modulus at high temperatures (such as increasing the crosslinking density or reducing the amount of CTBN toughening agent) often lead to a decline in the performance of other properties at room temperature (e.g., from about 20°C to about 25°C). There is a desire for a material that provides a higher tensile modulus at high temperatures while maintaining or improving adhesion and reinforcement properties at room temperature.

[0007] Therefore, the present invention aims to provide an improved toughening agent material for barrier, adhesion and / or reinforcement, which provides a higher tensile modulus retention rate at high temperatures compared with existing materials.

[0008] Carboxylated solid nitrile butadiene rubber (XNBR) has been used to toughen thermosetting formulations. Unlike CTBN, which has a low molecular weight and carboxyl groups located at the ends of the polymer chain, XNBR is a high molecular weight polymer with carboxyl groups randomly spaced along the polymer chain. This can cause the adduct to gel during synthesis or storage, and greatly limits the use of XNBR toughening agents. Co-pending U.S. Provisional Patent Application No. 63 / 359,513, filed July 8, 2022 (which is incorporated herein by reference in its entirety for all purposes), discloses the use of epoxy resin adducts of low-acid-content XNBR as storage-stable toughening agents.

[0009] Bascom et al. (WD Bascom, R. Y. Ting, R. J. Moulton, C. C. Riew, and A. R. Siebert, *Journal of Mat. Sci.*, Vol. 16, pp. 2657–2664, 1981) separately and jointly used CTBN-epoxy resin adducts and XNBR-epoxy resin adducts to demonstrate their effectiveness in improving the fracture toughness of epoxy thermosetting plastics. Although they identified differences between CTBN and XNBR in how they improved toughness, they did not disclose any information regarding the high-temperature properties of the materials.

[0010] We unexpectedly found that solid XNBR adducts exhibit acceptable properties at room temperature while simultaneously improving modulus retention at high temperatures. Without being constrained by theory, we believe that, as Bascom et al. have identified, due to the higher molecular weight of XNBR and the random distribution of its acid functional groups, the resulting microdomains are smaller and can achieve sufficient bonding with the continuous epoxy matrix while remaining phase-separated. This leads to a decrease in the homogeneity of the elastomer material in the continuous phase, thereby improving the tensile modulus retention at high temperatures. Summary of the Invention

[0011] This article teaches a solid rubber adduct derived from carboxylated nitrile butadiene rubber that can be used to toughen epoxy resin-based compositions and improve modulus retention at high temperatures.

[0012] This teaching further relates to a solid epoxy resin adduct comprising a reaction product of solid carboxylated nitrile butadiene rubber (XNBR) and an epoxy functional resin.

[0013] The carboxylic acid content of this solid carboxylated nitrile rubber can be less than 2% by weight.

[0014] The carboxylic acid content of this solid carboxylated nitrile rubber can be less than 1% by weight.

[0015] The solid carboxylated nitrile butadiene rubber (XNBR) may be present in an amount of at least 10% by weight.

[0016] This solid carboxylated nitrile butadiene rubber (XNBR) is a carboxylated, cold-polymerized butadiene-acrylonitrile terpolymer.

[0017] Epoxy functional resins used for addition reactions may include solid epoxy resins.

[0018] Epoxy functional resins used for addition reactions may include liquid epoxy resins.

[0019] This adduct can be a butadiene-acrylonitrile (CTBN) material without any carboxyl-terminated groups.

[0020] The adduct may contain polyvinyl butyral.

[0021] The polyvinyl butyral can be present in an amount of at least 5% or even at least 10%.

[0022] The adduct may contain at least two different epoxy functional resins.

[0023] The adduct may contain at least three different epoxy functional resins.

[0024] The adduct may contain a solvent.

[0025] This adduct may be solvent-free.

[0026] The adduct may contain metal carbonates.

[0027] This teaching also relates to an epoxy resin-based composition comprising a solid epoxy resin adduct comprising a reaction product of a solid carboxylated nitrile butadiene rubber (XNBR) and an epoxy functional resin.

[0028] The composition foams upon exposure to irritants.

[0029] The composition can foam when exposed to high temperatures (e.g., 120°C to 200°C).

[0030] Compared to compositions that include carboxyl-terminated butadiene-acrylonitrile (CTBN) adducts but do not contain XNBR-based adducts, the storage modulus of this composition can be increased (e.g., by at least 10%, at least 20%, or even at least 30%).

[0031] The composition may be free of any carboxyl-terminated butadiene-acrylonitrile (CTBN) adducts.

[0032] The composition may contain a foaming agent, a curing agent, or both.

[0033] The composition may contain polymer particles.

[0034] The composition can have adhesive properties.

[0035] This composition can have sealing properties.

[0036] The composition may have structural properties.

[0037] The composition can be a pressure-sensitive adhesive.

[0038] This solid carboxylated butadiene-acrylonitrile rubber adduct provides a tensile modulus measured according to ASTM D638, which is within 10% or less of the tensile modulus of the same composition having a butadiene-acrylonitrile (CTBN) adduct based on carboxyl groups.

[0039] When exposed to temperatures above 80°C, the modulus of the composition at room temperature (20°C to 25°C) may decrease by no more than 60%.

[0040] The volume expansion rate of this composition when using a solid carboxylated nitrile rubber adduct is greater than that when using a carboxyl-terminated butadiene-acrylonitrile (CTBN) adduct.

[0041] This teaching further relates to a solid epoxy resin adduct comprising a reaction product of a solid carboxylated nitrile butadiene rubber (XNBR), a first epoxy functional resin, an optional second epoxy functional resin, and a polyvinyl butyral additive. Detailed Implementation

[0042] The explanations and illustrations presented herein are intended to enable those skilled in the art to understand the content, principles, and practical applications of this teaching. The specific embodiments of this teaching described are not intended to be exhaustive or limiting. The scope of this teaching should be determined by reference to the appended claims and the full scope of their equivalents. All disclosures in articles and references (including patent applications and publications) are incorporated herein by reference for all purposes. Claims are also incorporated herein by reference where other combinations derived from the appended claims are possible. Unless otherwise stated, percentages herein refer to weight percentages.

[0043] One aspect of this teaching comprises a solid epoxy resin adduct composition, which can be used as a toughening agent in epoxy resin formulations, comprising the reaction product of low-acid-content XNBR and epoxy resin. Preferably, the carboxylic acid content percentage (COOH weight percentage) in the XNBR is less than 2%, and most preferably less than 1%, but other amounts are also possible. Sufficient acid content in the XNBR with a higher acid content may be consumed before reacting with the epoxy resin. However, it is preferred to use XNBR with a low acid content to simplify the overall reaction process. Krynac X146 and Krynac X160 from Arlanxeo are exemplary XNBRs with a carboxyl content of 0.5%. Both are carboxylated, cold-polymerized butadiene-acrylonitrile terpolymers.

[0044] The adduct can be prepared using liquid epoxy resins; however, if a solid thermosetting material is desired at room temperature, a solid additive may be necessary to ensure the final adduct is a brittle solid. Using solid epoxy resins is easier when reacting with XNBR because it simplifies the mixing of components before the reaction. Liquid epoxy resins can be added as part of the adduct reaction or after the reaction to adjust the softening temperature of the adduct or to alter the ratio of epoxide functional groups to carboxyl functional groups, thereby providing an excess of epoxide. In this paper, we define epoxy resins as resins having at least two epoxy groups.

[0045] This adduct can be prepared by either batch or continuous processes. The twin-arm sigma mixer, single-screw extruder, twin-screw extruder, and continuous kneader are merely some non-limiting examples of equipment that can be used to produce this adduct.

[0046] The adduct can be prepared at high temperatures, ranging from about 80°C to about 250°C, more preferably from about 100°C to about 200°C, and most preferably from about 110°C to about 165°C. The reaction can be carried out in the molten state, and the minimum temperature at which the reaction proceeds must be above the softening point of the reaction mixture. Solvents can be used to lower the softening point and viscosity of the reaction mixture. For finished adducts that are brittle solids and produce a 100% solids formulation, the solvent can be removed. However, it is preferable to carry out the reaction in the molten state in the absence of a solvent. Epoxy-acid reaction catalysts known in the art can be used, but are not essential. Phosphine (such as triphenylphosphine), tertiary amines (such as dimethylbenzylamine), quaternary ammonium compounds, and phosphorus compounds (such as ethyltriphenylphosphonium iodide) are a range of non-limiting potential catalysts.

[0047] The adduct may contain inert fillers. Metal carbonates (such as calcium carbonate), silicates (such as wollastonite or bentonite), clays (such as kaolin), and fumed silica are a range of unrestricted inorganic fillers. Thermoplastic polymers (such as polyvinyl butyral, phenoxy resins, polycarbonates, and ethylene copolymers and terpolymers) may also be part of the mixture. Other common thermosetting components (such as pigments, UV absorbers or stabilizers, free radical scavengers, and antioxidants) are also permitted.

[0048] This adduct can be formulated with additional materials to form an epoxy resin-based composition. The following components may be included in the epoxy resin-based formulation along with the adduct described herein. One or more materials listed below may also be included in the adduct itself.

[0049] Epoxy resin-based compositions, adducts, or both may include epoxy resin materials. The epoxy resin material may be any dimer, oligomer, or polymeric epoxy resin material containing at least one epoxy functional group. Furthermore, the term "epoxy resin" may be used to refer to one epoxy resin or a combination of multiple epoxy resins. Polymer-based materials may be epoxy resin-containing materials having one or more ethylene oxide rings that can be polymerized via a ring-opening reaction. Epoxy resin-based compositions, adducts, or both may include up to 80% or more of epoxy resin. Epoxy resin-based compositions, adducts, or both may include 2% to 70% by weight of epoxy resin, 4% to 30% by weight of epoxy resin, or even 7% to 18% by weight of epoxy resin. The epoxy resin may be aliphatic, alicyclic, aromatic, etc. The epoxy resin may be provided as a solid (e.g., as granules, blocks, flakes, etc.) or a liquid. The epoxy resin may include ethylene copolymers or terpolymers that may have α-olefins. The epoxy resin may include a phenolic resin, which may be a phenolic varnish type (e.g., epoxy phenolic varnish resin, epoxy cresol varnish resin, combinations thereof, etc.) or other types of resin. Other preferred epoxy resin-containing materials include bisphenol A epichlorohydrin polymers, or bisphenol A epoxy resins modified with butadiene or another polymer additive. Furthermore, various mixtures of several different epoxy resins may also be used. Examples of suitable epoxy resins are listed by trade name. (For example, DER 331, DER 661, DER 662) are available for purchase from Olin, Inc., Clayton, Missouri.

[0050] An exemplary material used in or in combination with adducts to form an epoxy resin-based composition is polyvinyl butyral (PVB). PVB may be at least about 5% by weight of the epoxy resin-based composition, more typically at least about 10% by weight, and even more typically at least about 15% by weight. PVB may be about 30% by weight or less of the epoxy resin-based composition, more typically about 25% by weight or less, and even about 20% by weight or less. Suitable examples of PVB include CCP PVB resin B08HX.

[0051] It is also possible that the adduct and / or epoxy-based composition includes at least one polymer particle. Such polymer particles can be used to improve fracture toughness (G). 1C Peel resistance and impact resistance. As used herein, as with any other component of this teaching, the term "polymer particles" may include one or more polymer particles. Various polymer particles may be used in the practice of this teaching and generally include one or more elastomers. Generally preferred is that the polymer particles constitute at least 4% by weight of the epoxy-based composition, more typically at least 7% by weight, even more typically at least 10% by weight, even more typically at least 13% by weight, and even more typically at least 16% by weight, and it is also preferred that the polymer particles constitute less than 90% by weight of the epoxy-based composition, more typically less than 40% by weight, and even more typically less than 30% by weight, although higher or lower amounts may be used in certain embodiments.

[0052] The polymer particles may include one or more core / shell polymers that may be pre-dispersed in an epoxy resin. Processes for forming core-shell materials in liquid epoxy resins avoid agglomeration of core-shell particles, whereas "dry" core-shell polymer particles are prone to agglomeration (e.g., agglomeration may occur during the drying process). Examples of products obtained by this process can be described in one or more of U.S. Patent Nos. 3,984,497, 4,096,202, 4,034,013, 3,944,631, 4,306,040, 4,495,324, 4,304,709, and 4,536,436. The polymer particles may be formed by an emulsion polymerization process. This process may include adding a solvent to the resin. Because the resin / solvent is immiscible with water, water is released from the material as the core-shell particles migrate into the resin, reducing agglomeration. Alternatively, high-speed dispersion can effectively depolymerize core / shell materials. However, surfactants may remain after the core / shell material has been spray-dried or solidified. This residual surfactant may impair the material's resistance to environmental exposure conditions involving water, such as salt spray and moisture. Materials not exposed to environmental conditions generally do not exhibit a difference between dry and liquid materials, provided the dry material has been sufficiently depolymerized.

[0053] As used herein, the term "core-shell polymer" can refer to a polymeric material in which a majority (e.g., greater than 30 wt%, 50 wt%, 70 wt%, or more) may comprise a first polymeric material (i.e., the first or core material), which may be substantially completely encapsulated by a second polymeric material (i.e., the second or shell material). As used herein, the first and second polymeric materials may comprise one, two, three, or more polymers combined together and / or reacted together (e.g., sequentially polymerized), or may be individual or part of the same core / shell system. The core / shell polymer should be compatible with the epoxy-based composition and preferably has a tough core and a rigid shell that exhibits good adhesion to the other components of the epoxy-based composition.

[0054] The first and second polymer materials of the core / shell polymer may include elastomers, polymers, thermoplastics, copolymers, other components, or combinations thereof. The first polymer material, the second polymer material, or both may include (e.g., at least 70%, 80%, 90% or more by weight) one or more thermoplastics, or may consist substantially entirely of them. Exemplary thermoplastics include, but are not limited to, styrene, acrylonitrile, acrylates, acetates, polyamides, polyethylene, or combinations thereof.

[0055] Examples of useful core-shell graft copolymers can be those in which a rigid compound (such as styrene, acrylonitrile, or methyl methacrylate) can be grafted onto a core made of a polymer of a soft or elastomeric compound (such as butadiene or butyl acrylate). U.S. Patent No. 3,985,703 describes a useful core-shell polymer with a core made of butyl acrylate, but it can also be based on ethyl isobutyl acrylate, 2-ethylhexyl acrylate, or other alkyl acrylates or mixtures thereof. The core polymer can also include other copolymerizable compounds such as styrene, vinyl acetate, methyl methacrylate, butadiene, isoprene, etc. The core polymer material can also include crosslinking monomers having two or more non-conjugated double bonds with substantially equal reactivity, such as ethylene glycol diacrylate, butanediol dimethacrylate, etc. The core polymer material can also include graft linking monomers having two or more non-conjugated double bonds with unequal reactivity, such as diallyl maleate and allyl methacrylate.

[0056] The shell portion can be polymerized from methyl acrylates (such as methyl methacrylate) and optionally other alkyl acrylates and alkyl methacrylates (such as acrylic acid or ethyl methacrylate, acrylic acid or butyl methacrylate, or mixtures thereof), as these materials are compatible with phenoxy resins and any epoxy resins used in the formulation. The content of styrene, vinyl acetate, vinyl chloride, etc., in the shell monomer can be up to 40% by weight or higher. Examples of core-shell graft copolymers include, but are not limited to, "MBS" (methyl methacrylate-butadiene-styrene) polymers, which are prepared by polymerizing methyl methacrylate in the presence of polybutadiene or polybutadiene copolymer rubber. MBS graft copolymer resins typically have a styrene-butadiene rubber core and an acrylic polymer or copolymer shell. Other examples of useful core-shell graft copolymer resins include ABS (acrylonitrile-butadiene-styrene), MABS (methacrylate-acrylonitrile-butadiene-styrene), ASA (acrylate-styrene-acrylonitrile), all acrylic resins, SA EPDM (styrene-acrylonitrile grafted onto the elastomer backbone of ethylene-propylene diene monomer), MAS (methacrylate-acrylic rubber-styrene), and mixtures thereof.

[0057] Examples of useful core / shell polymers include, but are not limited to, those sold under the trade name Kane Ace, commercially available from Kaneka Corporation. A particularly preferred grade of Kane Ace core / shell polymer is sold under the name MX-182 and commercially available from Arkema Corporation. The core / shell polymer can be from about 2% by weight to about 30% by weight in epoxy-based compositions.

[0058] The adduct or epoxy-based composition may include a softening agent. The term "softening agent" can be used to refer to a single softening agent or a combination of several different softening agents. While other softening agents may be used, preferred softening agents include polymers modified with amines, modified with epoxy resins, or simultaneously modified with both amines and epoxy resins. These polymers may include thermoplastics, thermosetting plastics or thermocurable materials, elastomers, combinations thereof, etc. These polymers may be modified with aromatic or non-aromatic epoxy resins, and / or with bisphenol F type epoxy resins, bisphenol A type epoxy resins, combinations thereof, or other types of epoxy resins.

[0059] Phenolic molecules (such as the softener Rez-Cure EP 1820, available from Innovative Resin Systems) are one possible material to utilize. Another preferred example of a softener is an epoxy-dimer elastomer sold under the trade name HYPOX DA 323, commercially available from CVC Specialty Chemicals. Other preferred examples of softeners are polyurethane-modified epoxy resins sold under the trade names GME-3210 and GME-3220, commercially available from GNS Technologies. Further examples of preferred softeners are amine-terminated or epoxy-terminated polyethers, such as JEFFAMINE D-2000 (available from Huntsman) and DER 732 (available from Dow Chemical Company). Softeners based on cashew nutshell liquid (such as epoxidized cashew nutshell liquid Cardolite NC-514 and Cardolite Lite) are also possible. 2513HP is also a useful softener. Unless otherwise stated, all individual softeners described herein may be used alone or in combination with each other in the compositions of the present invention.

[0060] Typically, the softener is at least 1% by weight of the adduct or epoxy-based composition, more typically at least 2% by weight, and even possibly at least 5% by weight, but typically less than 50% by weight of the material, more typically less than 35% by weight, and even possibly less than 20% by weight, but higher and lower values ​​are possible unless otherwise stated. In particular, it is also conceivable that in embodiments where the softener is modified with an epoxy component, the amount of softener can be higher.

[0061] One or more foaming agents can be added to epoxy resin-based compositions to generate inert gases that, as needed, form open and / or closed honeycomb structures within the epoxy resin-based composition. In this way, the density of articles made from this material can be varied according to the requirements of a specific application.

[0062] Blowing agents may include one or more nitrogen-containing groups, such as amides and amines. Examples of suitable blowing agents include azodicarbonamide, dinitrospentamethylenetetramine, and 4,4-dioxane. i -Oxo-bis-(benzenesulfonylhydrazine), trihydrazines and N,N i -dimethyl-N,N i -Dinitrosylterephthalamide. The material may include physical blowing agents, including but not limited to reagents such as Expancel, available from AkzoNobel. Alternatively, the material may be manufactured according to the MuCell process available from Trexel.

[0063] Accelerators for blowing agents can also be provided in epoxy resin-based compositions. Various accelerators can be used to increase the rate at which the blowing agent forms an inert gas. A preferred blowing agent accelerator is a metal salt or oxide (e.g., a metal oxide such as zinc oxide). Other preferred accelerators include modified and unmodified thiazoles, ureas, and imidazoles.

[0064] The amounts of foaming agents and foaming accelerators can vary widely in epoxy resin-based compositions, depending on the type of honeycomb structure desired, the desired expansion amount, the desired expansion rate, etc. Exemplary ranges for the amounts of foaming agents and foaming accelerators in epoxy resin-based compositions are from about 0.001% by weight to about 5% by weight, and preferably by weight percentage in the epoxy resin-based composition. The foaming agent can be at least about 0.5% by weight in the epoxy resin-based composition, more typically at least about 1% by weight, and even more typically about 1.2% by weight. The foaming agent can be about 2.5% by weight or less in the epoxy resin-based composition, more typically about 2.0% by weight or less, and even more typically about 1.8% by weight or less. Exemplary foaming agents include Cellcom AC7001 and... 754A.

[0065] This teaching also envisions omitting the foaming agent. However, the epoxy-based compositions, foaming agents, or both of this teaching may be thermally activated (e.g., the composition foams upon exposure to high temperatures). Alternatively, other agents may be used to achieve activation through other stimuli (such as moisture, radiation, etc.).

[0066] One or more curing agents and / or curing accelerators can be added to epoxy resin-based compositions. Similar to foaming agents, the amounts of curing agents and curing accelerators in epoxy resin-based compositions can vary widely, depending on factors such as the type of desired honeycomb structure, the required expansion amount of the epoxy resin-based composition, the required expansion rate, and the desired structural properties of the epoxy resin-based composition. An exemplary range of curing agents or curing accelerators present in epoxy resin-based compositions is from about 0.001% by weight to about 7% by weight.

[0067] Curing agents may assist in the curing of epoxy-based compositions through crosslinking reactions of polymers, epoxy resins, or both. Curing agents may also advance the curing process or chain extension of epoxy-based compositions. Useful categories of curing agents are materials selected from: aliphatic or aromatic amines and their respective adducts, amide amines, polyamides, alicyclic amines, acid anhydrides, polycarboxylic acid polyesters, isocyanates, phenol-based resins (e.g., phenol or cresol phenolic varnish resins, such as phenol-terpene copolymers, copolymers of polyvinylphenol or bisphenol A-formaldehyde copolymers, dihydroxyphenylalkanes, etc.), or mixtures thereof. Particularly preferred curing agents include modified and unmodified polyamines or polyamides, such as triethylenetetramine, diethylenetriamine, tetraethylenepentamine, cyanoguanidine, dicyandiamide, etc. Accelerators for curing agents (e.g., modified or unmodified ureas, such as methylene diphenyl diurea, imidazole, or combinations thereof) can also be provided to prepare epoxy-based compositions.

[0068] The following materials are used in the embodiments included herein:

[0069]

[0070]

[0071]

[0072] Example 1 and Example 2

[0073] 450 parts of Krynac X 146 (for Example 2) or a certain amount of Hypro 1300x13 (for Example 1) were added to a jacketed twin-arm mixer with a temperature control unit (TCU) set at 350°F and plasticized for several minutes. Then, 675 parts of YD-017 solid epoxy resin were added all at once and mixed until the epoxy resin melted and a homogeneous mixture was formed. Next, 675 parts of YD-019 epoxy resin were added in four portions over five minutes. After mixing for 50 minutes, the TCU setpoint was lowered to 340°F, and the mixture was mixed for another 3 hours. This maintained the mixture temperature between 315°F and 325°F. Next, the TCU setpoint was lowered to 300°F, and 200 parts of YD-128 liquid epoxy resin were added over five minutes. Mixing continued for another 30 minutes. The TCU setpoint was lowered to 250°F, the admixture was removed from the mixer, and rapidly cooled to room temperature. The material becomes a brittle solid upon cooling. Details of Examples 1 and 2 are listed in Table A below. Example 1 is a comparative example using CTBN, while Example 2 uses XNBR.

[0074] Table A

[0075]

[0076] Then, the adducts formed in Examples 1 and 2 were formulated into foamed epoxy resin-based compositions, as shown in Examples 3 (Comparative) and 4 (XNBR Adduct) in Table B below.

[0077] Table B

[0078]

[0079] *20% short-cut and fibrillated aramid fibers are blended with 80% type 1 epoxy resin.

[0080] The foamed epoxy resin-based compositions of Examples 3 and 4 were evaluated, and the following properties were obtained as shown in Table C.

[0081] Table C

[0082]

[0083]

[0084] *0.030” EG60, test speed: 254 mm / min, adhesion line 3 mm; **0.060” EG60, test speed: 50.4 mm / min, adhesion line 1.5 mm, 2.5 to 3.0 mg / sq inch. 61 MAL HCL; Curing conditions: 163℃ / 30 minutes

[0085] The characteristics shown in Table C indicate that the XNBR-based adduct (in Example 4) exhibits comparable or better performance compared to the CTBN-based adduct, and improves the modulus retention at 80°C.

[0086] Examples 5 and 6

[0087] Similar to the setup described in Examples 1 and 2, the TCU was set to 250°F, and 500 parts of Krynac X 146 were added to the mixer and plasticized for 5 minutes. Subsequently, 750 parts of Kukdo KD-214C epoxy resin were added over 8 minutes to obtain a homogeneous mixture. Next, the TCU setpoint was raised to 270°F, and another 750 parts of KD-214C were added over 8 minutes. Then, the TCU setpoint was raised to 320°F and mixing continued for 53 minutes. Subsequently, the TCU setpoint was raised to 330°F and mixing continued for 150 minutes. The material was then removed from the mixer and rapidly cooled to obtain a brittle solid. The compositions of Examples 5 and 6 are shown in Table D below.

[0088] Table D

[0089]

[0090] The adducts of Examples 5 and 6 were then formulated into foamed epoxy resin-based compositions, as shown in Table E below for Examples 5 (Comparative) and Example 6 (XNBR Adduct).

[0091] Table E

[0092]

[0093] The foamed epoxy-based compositions of Examples 7 and 8 (cured at 163°C for 30 minutes) were evaluated, and the following properties were obtained as shown in Table F.

[0094] Table F

[0095]

[0096]

[0097] *0.030” EG60, test speed: 254 mm / min, adhesion line 3 mm; **0.060” EG60, test speed: 50.4 mm / min, adhesion line 1.5 mm, 2.5 to 3.0 mg / sq inch. 61MAL HCL; Curing conditions: 163°C / 30 minutes

[0098] The preceding examples demonstrate that using materials containing XNBR adducts improves modulus retention, even when using small amounts of adducts.

[0099] Examples 9 and 10

[0100] The adducts having the following compositions were prepared by a single feeding process as described in Examples 1 and 2. After incorporation of YD-128, thermoplastic polyvinyl butyral (PVB) was added and mixed for several minutes to ensure homogeneity. The mixture was then removed from the mixer and rapidly cooled to room temperature to obtain a brittle solid. Table G below shows the compositions of Examples 9 and 10.

[0101] Table G

[0102]

[0103] The solid adducts of Examples 9 and 10 were formulated into foamed epoxy resin-based compositions (in this case, pressure-sensitive adhesives) as shown in Examples 11 and 12 in Table H below.

[0104] Table H

[0105]

[0106]

[0107] The foamed epoxy resin-based compositions of Examples 11 and 12 were evaluated, and the following properties are shown in Table I.

[0108] Table I

[0109]

[0110]

[0111] *0.030” EG60, test speed: 254 mm / min, adhesion line 3 mm; **0.060” EG60, test speed: 50.4 mm / min, adhesion line 1.5 mm, 2.5 to 3.0 mg / sq inch. 61 MAL HCL; Curing conditions: 163℃ / 30 minutes

[0112] The above embodiments demonstrate that the modulus retention rate is improved in foamed thermosetting pressure-sensitive adhesives.

[0113] As used herein, unless otherwise stated, any member of the genus (list) of the teachings may be excluded from that genus; and / or any member of the Markush group may be excluded from that group.

[0114] Unless otherwise stated, the numerical values ​​described herein include all values ​​from lower to higher, in increments of one unit, provided that there is at least a two-unit interval between any lower and any higher value. For example, if the value of a stated amount, characteristic, or process variable (e.g., temperature, pressure, time, etc.) is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, then it is intended that intermediate range values ​​(e.g., 15 to 85, 22 to 68, 43 to 51, 30 to 32, etc.) are within the teachings of this specification. Similarly, individual intermediate values ​​are also within the teachings. For values ​​less than 1, one unit is considered as 0.0001, 0.001, 0.01, or 0.1, as appropriate. These are merely examples of specific intentions, and all possible combinations of numerical values ​​between the listed minimum and maximum values ​​should be considered as those explicitly stated in this application in a similar manner. It can be seen that the teachings of quantities expressed herein as "parts by weight" also contemplate the same range expressed as weight percentages. Therefore, the description of the resulting composition in the range of "at least" x parts by weight also envisions the teaching of the same enumerated range of "x" of "weight percentage of the resulting composition".

[0115] Unless otherwise stated, all ranges include both endpoints and all numbers between them. The use of "about" or "approximately" in relation to ranges applies to both ends of the range. Thus, "about 20 to 30" is intended to encompass "about 20 to about 30," including at least the specified endpoints.

[0116] All publications in articles and references (including patent applications and publications) are incorporated herein by reference for all purposes. The term "consistently of..." used to describe a combination shall include the identified element, component, element, or step, as well as any other such element, component, element, or step that does not substantially affect the essential and novel features of the combination. The terms "comprising" or "including" used herein to describe combinations of elements, components, elements, or steps also contemplate embodiments that consist of or are substantially composed of such elements, components, elements, or steps.

[0117] Multiple elements, components, ingredients, or steps may be provided by a single integrated element, component, ingredient, or step. Alternatively, a single integrated element, component, ingredient, or step may be divided into multiple independent elements, components, ingredients, or steps. The use of "a" or "an" to describe an element, component, ingredient, or step is not intended to exclude additional elements, components, ingredients, or steps.

[0118] It should be understood that the above description is exemplary and not restrictive. Many embodiments and applications beyond those provided will become apparent to those skilled in the art after reading the above description. Therefore, the scope of the invention should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. All disclosures in articles and references (including patent applications and publications) are incorporated herein by reference for all purposes. The omission of any aspect of the subject matter disclosed herein in the appended claims is not a disclaimer of liability for this subject matter, nor should it be construed as the inventor considering such subject matter to be outside the scope of the disclosed inventive subject matter.

Claims

1. A solid epoxy resin adduct, comprising the reaction product of the following components: (i) Solid carboxylated nitrile butadiene rubber (XNBR); and (ii) Epoxy functional resins.

2. The adduct according to claim 1, wherein the carboxylic acid content of the solid carboxylated nitrile rubber is less than 2% by weight.

3. The adduct according to claim 1, wherein the solid carboxylated nitrile rubber has a carboxylic acid content of less than 1% by weight.

4. The adduct according to any one of the prior claims, wherein the solid carboxylated nitrile butadiene rubber (XNBR) is present in an amount of at least 10% by weight.

5. The adduct according to any one of the prior claims, wherein the solid carboxylated nitrile rubber (XNBR) is a carboxylated, cold-polymerized butadiene-acrylonitrile terpolymer.

6. The adduct according to any one of the prior claims, wherein the epoxy functional resin used for the adduct reaction comprises a solid epoxy resin.

7. The adduct according to any one of the prior claims, wherein the epoxy functional resin used for the adduct reaction comprises a liquid epoxy resin.

8. The adduct according to any one of the prior claims, wherein the adduct does not contain any carboxyl-terminated butadiene-acrylonitrile (CTBN) material.

9. The adduct according to any one of the prior claims, wherein the adduct comprises polyvinyl butyral.

10. The adduct of claim 9, wherein the polyvinyl butyral is present in an amount of at least 5% or even at least 10%.

11. The adduct according to any one of the prior claims, wherein the adduct comprises at least two different epoxy functional resins.

12. The adduct according to any one of the prior claims, wherein the adduct comprises at least three different epoxy functional resins.

13. The adduct according to any one of the prior claims, wherein the adduct comprises a solvent.

14. The adduct according to any one of the prior claims, wherein the adduct is free of any solvent.

15. The adduct according to any one of the prior claims, wherein the adduct comprises a metal carbonate.

16. An epoxy resin-based composition comprising the adduct according to any one of claims 1 to 15.

17. The composition of claim 16, wherein the composition is foam-forming upon exposure to a stimuli.

18. The composition of claim 16, wherein the composition is foamable when exposed to high temperatures (e.g., 120°C to 200°C).

19. The composition according to any one of claims 16 to 18, wherein, Compared to compositions that include carboxyl-terminated butadiene-acrylonitrile (CTBN) adducts but do not contain XNBR-based adducts, the storage modulus of the compositions is increased (e.g., by at least 10%, at least 20%, or even at least 30%).

20. The composition according to any one of claims 16 to 19, wherein the composition does not contain any carboxyl-terminated butadiene-acrylonitrile (CTBN) adduct.

21. The composition according to any one of claims 16 to 20, wherein the composition comprises a foaming agent, a curing agent, or both.

22. The composition according to any one of claims 16 to 21, wherein the composition comprises polymer particles.

23. The composition according to any one of claims 16 to 22, wherein the composition has adhesive properties.

24. The composition according to any one of claims 16 to 22, wherein the composition has sealing properties.

25. The composition according to any one of claims 16 to 22, wherein the composition has structural characteristics.

26. The composition according to any one of claims 16 to 22, wherein the composition is a pressure-sensitive adhesive.

27. The composition according to any one of claims 16 to 26, wherein the solid carboxylated butadiene-acrylonitrile rubber adduct provides a tensile modulus measured according to ASTM D638, said tensile modulus being in the range of 10% or less of the tensile modulus of the same composition having a carboxyl-terminated butadiene-acrylonitrile (CTBN) adduct.

28. The composition according to any one of claims 16 to 27, wherein, When exposed to temperatures above 80°C, the modulus of the composition at room temperature (20°C to 25°C) does not decrease by more than 60%.

29. The composition according to any one of claims 16 to 28, wherein the volume expansion rate of the composition when using the solid carboxylated nitrile rubber adduct is greater than that when using the carboxyl-terminated butadiene-acrylonitrile (CTBN) adduct.

30. A solid epoxy resin adduct comprising a reaction product of the following components: (i) Solid carboxylated acrylonitrile butadiene rubber (XNBR); (ii) First epoxy functional resin; (iii) An optional second epoxy functional resin; and (iv) Polyvinyl butyral additive.

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