EP4739725A1 - Toughening agents with improved modulus retention - Google Patents

Abstract

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

Description

TOUGHENING AGENTS WITH IMPROVED MODULUS RETENTION

CLAIM OF PRIORITY

[001] This application claims the benefit of the filing date of United States Provisional Application No. 63/525,598, filed July 7, 2023, the contents of that application being incorporated by reference herein in its entirety and for all purposes.

FIELD OF THE INVENTION

[002] The present teachings relate generally to solid carboxylated nitrile rubber-epoxy adducts useful as toughening agents in epoxy-based compositions for improving the modulus retention at elevated temperatures.

BACKGROUND OF THE INVENTION

[003] For many years industry, and particularly the transportation industry, has been concerned with acoustic attenuation, adhesion, and reinforcement of articles of manufacture such as automotive vehicles. In turn, industry has developed a wide variety of materials for providing such sound baffling, adhesion, and reinforcement. Some of the more desirable properties for adhesion and reinforcing materials include high tensile modulus, high strain to failure, and adhesion durability.

[004] Epoxy thermosets, formulated with liquid carboxy terminated nitrile rubber (CTBN) containing toughening agents, are materials that satisfy most requirements. During curing most of the CTBN agents become incompatible with the curing epoxy and form separate low glass transition temperature (Tg) elastomeric domains which improve the fracture toughness of the cured thermoset material. The portion of the CTBN material that does not phase separate bonds into in the continuous epoxy matrix. This can lead to a reduction in the modulus or Tg due to the presence of low Tg elastomeric material in the matrix. When properly formulated, these thermoset materials provide an acceptable balance of properties such as adhesion, tensile modulus, strain to failure, peel resistance, and fracture toughness at ambient temperatures.

[005] One continuing challenge with these materials is the ability to maintain performance at elevated temperatures. Methods to increase the modulus at elevated temperatures, such as increasing crosslink density or decreasing the amount of CTBN toughening agents, often result in reduced performance in other properties at ambient temperatures (e.g., about 20 °C to about 25 °C). It is desirable to have a material that provides increased tensile modulus at elevated temperatures, while maintaining or improving adhesion and reinforcement performance at ambient temperatures.

[006] The present invention, therefore, seeks to provide an improved toughening agent material for baffling, adhesion, and/or reinforcement that provides for increased tensile modulus retention at elevated temperatures, as compared to existing materials.

[007] Carboxylated solid nitrile rubbers (XNBRs) have been used to toughen thermoset formulations. Unlike CTBN with a low molecular weight and carboxyl groups at the ends of the polymer chain, XNBRs are high molecular weight polymers with carboxylic groups randomly spaced along the polymer chain. This can lead to adduct gelation during synthesis or storage and greatly limits the use of XNBR toughening agents. Co-pending United States Provisional Application No. 63/359,513 filed on July 8, 2022 (which is incorporated by reference herein in its entirety for all purposes) discloses the use of epoxy adducts of low acid containing XNBRs as storage stable toughening agents.

[008] Bascom et al. (W.D. Bascom, R.Y. Ting, R. J. Moulton, C. K. Riew, and A. R. Siebert, J. of Mat. Sci., 16, 2657-2664, 1981) utilized CTBN- and XNBR- epoxy adducts separately and in combination to demonstrate their effectiveness in improving the fracture toughness of epoxy thermosets. While they identified a difference in the way CTBN and XNBR improved toughness, they did not disclose any information regarding elevated temperature behavior.

[009] We have surprisingly discovered that solid XNBR adducts provide acceptable performance at ambient temperatures while improving modulus retention at elevated temperatures. Without being bound by theory, we believe the smaller domain size, identified by Bascom et al, arising from the higher molecular weight of XNBRs with their random acid functionality provides sufficient bonding to the continuous epoxy matrix while still being phase separated. This leads to less homogeneous elastomeric material in the continuous phase and subsequently improved tensile modulus retention at elevated temperatures.

SUMMARY OF THE INVENTION

[0010] The teachings herein provide for a solid rubber adduct derived from a carboxylated nitrile rubber useful in toughening epoxy-based compositions with improved modulus retention at elevated temperatures.

[0011] The teachings herein are further directed to a solid, epoxy adduct comprising the reaction product of a solid carboxylated nitrile rubber (XNBR) and an epoxy functional resin. [0012] A carboxylic acid content of the solid carboxylated nitrile rubber may be less than 2% by weight.

[0013] A carboxylic acid content of the solid carboxylated nitrile rubber may be less than 1 % by weight.

[0014] The solid carboxylated nitrile rubber (XNBR) may be present in an amount of at least 10% by weight.

[0015] The solid carboxylated nitrile rubber (XNBR) is a carboxylated cold polymerized butadiene acrylonitrile terpolymer.

[0016] The epoxy functional resin for the adduction reaction may comprise a solid epoxy resin.

[0017] The epoxy functional resin for the adduction reaction may comprise a liquid epoxy resin.

[0018] The adduct may be free of any carboxyl terminated butadiene acrylonitrile (CTBN) material.

[0019] The adduct may comprise polyvinyl butyral.

[0020] The polyvinyl butyral may be present in an amount of at least 5%, or even at least 10%.

[0021] The adduct may comprise at least two different epoxy-functional resins.

[0022] The adduct may comprise at least three different epoxy-functional resins.

[0023] The adduct may comprise a solvent.

[0024] The adduct may be free of any solvent.

[0025] The adduct may comprise a metal carbonate.

[0026] Th teachings herein are also directed to an epoxy-based composition comprising a solid, epoxy adduct comprising the reaction product of a solid carboxylated nitrile rubber (XNBR) and an epoxy functional resin.

[0027] The composition may be foamable upon exposure to a stimulus.

[0028] The composition may be foamable upon exposure to elevated temperatures (e.g., 120 °C to 200 °C).

[0029] The composition may have an improved storage modulus (e.g., an improvement of at least 10%, at least 20%, or even at least 30%) as compared to a composition that includes a carboxyl terminated butadiene acrylonitrile (CTBN)-based adduct and no XNBR-based adduct.

[0030] The composition may be free of any carboxyl terminated butadiene acrylonitrile (CTBN)- based adducts.

[0031] The composition may comprise a blowing agent, a curing agent, or both.

[0032] The composition may comprise a polymeric particle.

[0033] The composition may have adhesive properties. [0034] The composition may have sealing properties.

[0035] The composition may have structural properties.

[0036] The composition may be a pressure-sensitive adhesive.

[0037] The solid carboxylated nitrile rubber adduct may provide for a tensile modulus as measured in accordance with ASTM D638 that is within 10% or less of the tensile modulus of the same composition with a carboxyl terminated butadiene acrylonitrile (CTBN)-based adduct. [0038] The modulus of the composition at room 20 °C to 25 °C may not decrease by more than 60% when exposed to temperatures of more than 80 °C.

[0039] The volume expansion of the composition may be greater with the solid carboxylated nitrile rubber adduct than with a carboxyl terminated butadiene acrylonitrile (CTBN)-based adduct.

[0040] The teachings herein are further directed to a solid, epoxy adduct comprising the reaction product of a solid carboxylated nitrile rubber (XNBR), a first epoxy functional resin, an optional second epoxy functional resin, and a polyvinyl butyral additive.

DETAILED DESCRIPTION

[0041] The explanations and illustrations presented herein are intended to acquaint others skilled in the art with the present teachings, its principles, and its practical application. The specific embodiments of the present teachings as set forth are not intended as being exhaustive or limiting of the present teachings. The scope of the present teachings should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. Other combinations are also possible as will be gleaned from the following claims, which are also hereby incorporated by reference into this written description. Percentages herein refer to weight percent, unless otherwise indicated.

[0042] One aspect of the present teachings comprises a solid epoxy adduct composition, useful as a toughening agent in epoxy formulations, comprising the reaction product of an XNBR of low acid content and an epoxy resin. Preferably, the percent carboxylic acid content (percent by weight COOH) in the XNBR is less than 2% and most preferably less than 1%, though other amounts are potentially possible. It may be possible to consume sufficient acid content of XNBRs of higher acid content prior to reacting with epoxy resins. It is preferable, however, to use an XNBR with low acid content to simplify the overall reaction process. Krynac X 146 and Krynac X 160 from Arlanxeo are exemplary XNBR with a carboxyl content of 0.5%. Both are examples of carboxylated, cold polymerized butadiene acrylonitrile terpolymers.

[0043] The adduct may be made with liquid epoxy resins but may require solid additives to ensure the completed adduct is a friable solid if the desire is to have a thermoset material that is solid at room temperature. It is easier to use solid epoxy resins when reacting with the XNBR because mixing of the constituents prior to reaction is simplified. Liquid epoxy resins can be a part of the adduction reaction or added post-reaction to adjust the softening temperature of the adduct or change the ratio of epoxide to carboxyl functionality to provide greater epoxide excess. Herein we define an epoxy resin as a resin with at least two epoxy groups.

[0044] The adduct can be made in a batch process or continuous process. Double arm sigma mixers, single screw extruders, twin screw extruders, and continuous kneaders are just a few non-limiting examples of equipment that can be used to produce the adduct.

[0045] The adduct may be manufactured at elevated temperatures which may be in the range of 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 may be carried out in the melt state and the minimum temperature for the reaction must be above the softening point of the reacting mixture. A solvent can be used to lower the softening point as well as the viscosity of the reacting mixture. The solvent may have to be removed for the finished adduct to be a friable solid and produce 100% solid formulated compositions. It may be preferable, however, to perform the reaction in the molten state in the absence of solvents. Epoxy-acid reaction catalysts, known in the art, can be used but are not necessary. Phosphines, such as triphenyl phosphine, tertiary amines, such as dimethylbenzyl amine, quarternary ammonium and phosphonium compounds such as ethyltri phenyl phosphonium iodide are a non-limiting list of potential catalysts.

[0046] The adduct can contain inert fillers. Metal carbonates such as calcium carbonate, silicates such as wollastonite or garamite, clays such as kaolin, fumed silica, are a non-limiting list of inorganic fillers. Thermoplastic polymers such as polyvinyl butyral, phenoxy resins, polycarbonate, and ethylene co- and ter-polymers can also be part of the mixture. Other common thermoset ingredients such as pigments, UV absorbers or stabilizers, radical scavengers, antioxidants are permissible.

[0047] The adduct may be formulated with additional materials to form an epoxy-based composition. The following components may be included in the epoxy-based formula with the adduct described herein. It is also possible that one or more of the materials listed below may be included in the adduct itself.

[0048] The epoxy-based composition, the adduct, or both may include an epoxy material. The epoxy may be any dimeric, oligomeric or polymeric epoxy materials containing at least one epoxy functional group. Moreover, the term epoxy can be used to denote one epoxy or a combination of multiple epoxies. The polymer-based materials may be epoxy-containing materials having one or more oxirane rings polymerizable by a ring opening reaction. The epoxy-based composition, the adduct, or both may include up to 80% or more of an epoxy. The epoxy-based composition, the adduct, or both may include between 2% and 70% by weight epoxy, between 4% and 30% by weight epoxy, or even between 7% and 18% by weight epoxy. The epoxy may be aliphatic, cycloaliphatic, aromatic or the like. The epoxy may be supplied as a solid (e.g., as pellets, chunks, pieces or the like) or a liquid. The epoxy may include an ethylene copolymer or terpolymer that may possess an alpha-olefin. The epoxy may include a phenolic resin, which may be a novolac type (e.g., an epoxy phenol novolac, an epoxy cresol novolac, combinations thereof, or the like) or other type resin. Other preferred epoxy containing material includes a bisphenol-A epichlorohydrin ether polymer, or a bisphenol-A epoxy resin which may be modified with butadiene or another polymeric additive. Moreover, various mixtures of several different epoxies may be employed as well. Examples of suitable epoxies are sold under the trade name DER® (e.g., DER 331 , DER 661 , DER 662), commercially available from Olin, Inc., Clayton Missouri.

[0049] An exemplary material for including in the adduct or combining with the adduct to form the epoxy-based composition is polyvinyl butyral (PVB). Polyvinyl butyral may be approximately at least about 5% by weight, more typically at least about 10% by weight, and even more typically at least about 15% by weight of the epoxy-based composition. Polyvinyl butyral may be approximately about 30% or less by weight, more typically about 25% or less by weight, and even about 20% or less by weight of the epoxy-based composition. A suitable example of polyvinyl butyral may include CCP Polyvinyl Butyral resin B08HX.

[0050] It is also possible that the adduct ad/or the epoxy-based composition includes at least one polymeric particle. Such polymeric particles may be utilized to improve fracture toughness (Gic), peel resistance and impact resistance. As used herein, like with any other ingredients of the present teachings, the term “polymeric particle” can include one or more polymeric particles. Various polymeric particles may be employed in the practice of the present teachings and often include one or more elastomers. It is generally preferable for the polymeric particles to be at least 4%, more typically at least 7%, even more typically at least 10%, still more typically at least 13% and even still more typically at least 16% by weight of the epoxy-based composition and also preferable for the polymeric particle to be less than 90%, more typically less than 40% an even more typically less than 30% by weight of the epoxy-based composition, although higher or lower amounts may be used in particular embodiments.

[0051] The polymeric particle may include one or more core/shell polymers which may be predispersed in an epoxy. The process for forming the core shell materials in a liquid epoxy avoids agglomeration of the core shell particles as may be common with “dry” core shell polymeric particles (e.g., agglomeration may occur during the drying process). An example of products made by this process may 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 polymeric particles may be formed through an emulsion polymerization process. This process may include the addition of a solvent with the resin. As a result of incompatibility between the resin/solvent and water, the water settles out of the material as the core shell particles move into the resin, resulting in reduced agglomeration. Alternatively, a high speed dispersion can be effective at de-agglomerating core/shell materials. However a surfactant may remain post spray drying or coagulating the core/shell material. This residual surfactant may be detrimental for the material's resistance to environmental exposure conditions that involve water such as salt spray and humidity. Materials not exposed to the environmental exposure conditions would typically not show a difference between dry and liquid provided that there is sufficient de-agglomeration of the dry material.

[0052] As used herein, the term core shell polymer may denote a polymeric material wherein a substantial portion (e.g., greater than 30%, 50%, 70% or more by weight) thereof may be comprised of a first polymeric material (i.e., the first or core material) that may be substantially entirely encapsulated by a second polymeric material (i.e., the second or shell material). The first and second polymeric materials, as used herein, may be comprised of one, two, three or more polymers that are combined and/or reacted together (e.g., sequentially polymerized) or may be part of separate or same core/shell systems. The core/shell polymer should be compatible with the epoxy-based composition and preferably has a ductile core and a rigid shell which has favorable adhesion with the other components of the epoxy-based composition.

[0053] The first and second polymeric materials of the core/shell polymer can include elastomers, polymers, thermoplastics, copolymers, other components, or combinations thereof. The first polymeric material, the second polymeric material or both may include or may be substantially entirely composed of (e g., at least 70%, 80%, 90% or more by weight) one or more thermoplastics. Exemplary thermoplastics include, without limitation, styrenics, acrylonitriles, acrylates, acetates, polyamides, polyethylenes, or combinations thereof.

[0054] Examples of useful core-shell graft copolymers may be those where hard containing compounds, such as styrene, acrylonitrile or methyl methacrylate, may be grafted onto a core made from polymers of soft or elastomeric compounds such as butadiene or butyl acrylate. United States Patent No. 3,985,703, describes useful core-shell polymers, the cores of which are made from butyl acrylate but can be based on ethyl isobutyl, 2-ethylhexyl or other alkyl acrylates or mixtures thereof. The core polymer may also include other copolymerizable containing compounds, such as styrene, vinyl acetate, methyl methacrylate, butadiene, isoprene, or the like. The core polymer material may also include a cross linking monomer having two or more nonconjugated double bonds of approximately equal reactivity such as ethylene glycol diacrylate, butylene glycol dimethacrylate, and the like. The core polymer material may also include a graft linking monomer having two or more nonconjugated double bonds of unequal reactivity such as, for example, diallyl maleate and allyl methacrylate.

[0055] The shell portion may be polymerized from methyl acrylates such as methyl methacrylate and optionally other alkyl acrylates and methacrytates, such as ethyl, butyl, or mixtures thereof acrylates or methacrylates as these materials are compatible with the phenoxy resin and any epoxy resins that are used in the formulation. Up to 40 percent by weight or more of the shell monomers may be styrene, vinyl acetate, vinyl chloride, and the like. Examples of core-shell graft copolymers include, but are not limited to, "MBS" (methacrylate-butadiene- styrene) polymers, which are made by polymerizing methyl methacrylate in the presence of polybutadiene or a polybutadiene copolymer rubber. The MBS graft copolymer resin may generally have a styrene butadiene rubber core and a shell of acrylic polymer or copolymer. Examples of other useful core-shell graft copolymer resins include, ABS (acrylonitrile-butadiene- styrene), MABS (methacrylate-acrylonitrile-butadiene-styrene), ASA (acrylate-styrene- acrylonitrile), all acrylics, SA EPDM (styrene- acrylonitrile grafted onto elastomeric backbones of ethylene-propylene diene monomer), MAS (methacrylic-acrylic rubber styrene), and mixtures thereof.

[0056] Examples of useful core/shell polymers include but are not limited to those sold under the tradename, Kane Ace, commercially available from Kaneka. Particularly preferred grades of Kane Ace core/shell are sold under the designation MX-182 available from Arkema. The core/shell polymer may be from about 2% to about 30% by weight of the epoxy-based composition.

[0057] The adduct or the epoxy-based composition may include a flexibilizer. The use of the term flexibilizer can relate to a single flexibilizer or a combination of multiple different flexibilizers. Although other flexibilizers may be employed, preferred flexibilizers include polymers that are amine modified, epoxy modified, or both. These polymers can include thermoplastics, thermosets or thermosettables, elastomers, combinations thereof or the like. These polymers may be modified with aromatic or non-aromatic epoxy and/or may be modified with bisphenol-F type, bisphenol-A type, combinations thereof or other type epoxy.

[0058] Phenol-containing molecules such as the flexibilizer Rez-Cure EP 1820 (available from Innovative Resin Systems) is one possible material that may be utilized. An example of another preferred flexibilizer is an epoxy-dimer acid elastomer sold under the tradenames HYPOX DA 323, commercially available from CVC Specialty Chemicals. An example of other preferred flexibilizers are polyurethane modified epoxies sold under the tradenames GME-3210 and GME-3220, commercially available from GNS Technologies. Yet further examples of preferred flexibilizer are amine or epoxy terminated polyethers such as JEFFAMINE D-2000, commercially available from Huntsman and DER 732, commercially available from the Dow Chemical Company. Flexibilizers based on cashew nutshell liquid such as the epoxidized liquids Cardolite NC-514 and Cardolite Lite 2513 HP are also useful flexibilizers. All of the individual flexibilizers discussed herein may be used separately or in combination with each other in the composition of the present invention, unless otherwise stated.

[0059] Typically, the flexibilizer is at least 1 %, more typically at least 2% and even possibly at least 5% by weight of the adduct or epoxy-based composition but is typically less than 50%, more typically less than 35% and even possibly less than 20% by weight of the material, although higher and lower values may also be possible unless otherwise stated. It is also contemplated in particular that the amount of flexibilizing agent may be higher in embodiments where the agent is modified with an epoxy component.

[0060] One or more blowing agents may be added to the epoxy-based composition for producing inert gases that form, as desired, an open and/or closed cellular structure within the epoxy-based composition. In this manner, it may be possible to modify the density of articles fabricated from the material as required for a particular application.

[0061] The blowing agent may include one or more nitrogen containing groups such as amides, amines and the like. Examples of suitable blowing agents include azodicarbonamide, dinitrosopentamethylenetetramine, 4,4j-oxy-bis-(benzenesulphonylhydrazide), trihydrazinotriazine and N,Nj-dimethyl-N,Nj-dinitrosoterephthalamide. The material may include a physical blowing agent, including but not limited to agents such as Expancel available from AkzoNobel. Alternatively, the material may be manufactured according to the MuCell process available from Trexel.

[0062] An accelerator for the blowing agents may also be provided in the epoxy-based composition. Various accelerators may be used to increase the rate at which the blowing agents form inert gasses. One preferred blowing agent accelerator is a metal salt, or is an oxide, e.g. a metal oxide, such as zinc oxide. Other preferred accelerators include modified and unmodified thiazoles, ureas and imidazoles.

[0063] Amounts of blowing agents and blowing agent accelerators can vary widely within the epoxy-based composition depending upon the type of cellular structure desired, the desired amount of expansion, the desired rate of expansion and the like. Exemplary ranges for the amounts of blowing agents and blowing agent accelerators in the epoxy-based composition range from about 0.001% by weight to about 5% by weight and are preferably in the epoxybased composition in fractions of weight percentages. The blowing agent may be at least about 0.5% by weight, more typically at least about 1 % by weight, and even more typically about 1.2% by weight of the epoxy-based composition. The blowing agent may be about 2.5% or less by weight, more typically about 2.0% or less by weight, and even more typically about 1.8% or less by weight of the epoxy-based composition. Exemplary blowing agents may include Cellcom AC7001 and Celogen® 754A.

[0064] The present teachings also contemplate the omission of a blowing agent. However, the epoxy-based composition, the blowing agent, or both of the present teachings may be thermally activated (e.g., the composition foams upon exposure to elevated temperatures). Alternatively, other agents may be employed for realizing activation by other stimulus, such as moisture, radiation, or otherwise.

[0065] One or more curing agents and/or curing agent accelerators may be added to the epoxybased composition. Amounts of curing agents and curing agent accelerators can, like the blowing agents, vary widely within the epoxy-based composition depending upon the type of cellular structure desired, the desired amount of expansion of epoxy-based composition, the desired rate of expansion, the desired structural properties of the epoxy-based composition and the like. Exemplary ranges for the curing agents or curing agent accelerators present in the epoxy-based composition range from about 0.001 % by weight to about 7% by weight. [0066] It is possible that the curing agents assist the epoxy-based composition in curing by crosslinking of the polymers, epoxy resins or both. It is also possible for the curing agents to assist in advancing or chain extending the epoxy-based composition. Useful classes of curing agents are materials selected from aliphatic or aromatic amines or their respective adducts, amidoamines, polyamides, cycloaliphatic amines, anhydrides, polycarboxylic polyesters, isocyanates, phenol-based resins (e.g., phenol or cresol novolak resins, copolymers such as those of phenol terpene, polyvinyl phenol, or bisphenol-A formaldehyde copolymers, bishydroxyphenyl alkanes or the like), or mixtures thereof. Particular preferred curing agents include modified and unmodified polyamines or polyamides such as triethylenetetramine, diethylenetriamine tetraethylenepentamine, cyanoguanidine, dicyandiamides and the like. An accelerator for the curing agents (e.g., a modified or unmodified urea such as methylene diphenyl bis urea, an imidazole or a combination thereof) may also be provided for preparing the epoxy-based composition.

[0067] The following materials are utilized in the examples included herein:

[0068] Examples 1 and 2

[0069] To a jacketed double arm mixer tempered by a hot oil temperature control unit (TCU) set at 350 °F, 450 parts of Krynac X 146 (for Example 2) or an amount of Hypro 1300x13 (for Example 1) are added to the mixer and masticated for several minutes. Then 675 parts of YD- 017 solid epoxy resin are added all at once and the system mixed until the epoxy resin melted and formed a homogenous mixture. Then 675 parts of YD-019 epoxy are added in four parts over five minutes. After fifty minutes of mixing the TCU setpoint is lowered to 340 °F and the mixture is mixed for an additional three hours. This maintains the mixture temperature at 315- 325 °F. Next, the TCU setpoint is lowered to 300 °F and 200 parts of YD-128, liquid epoxy resin are added over five minutes. Mixing continues for an additional 30 minutes. The TCU setpoint is lowered to 250 °F, the adduct is pulled from the mixer and quickly cooled to room temperature. The material is a friable solid upon cooling. Details of Examples 1 and 2 are set forth below at Table A. Example 1 is the comparative example using CTBN where Example 2 uses XNBR.

[0070] Table A

[0071] The adducts formed in Examples 1 and 2 are then formulated into foaming epoxy-based composition as shown below in Example 3 (comparative) and Example 4 (XNBR adduct) at Table B.

[0072] Table B

*20% of chopped and fibrillated aramid fiber compounded with 80% type 1 epoxy resin.

[0073] Evaluation of the foaming epoxy-based compositions of Examples 3 and 4 yielded the following properties shown at Table C.

[0074] Table C

*0.030” EG60, test speed:254 mm/min, bondline 3 mm; **0.060” EG60, test speed: 50.4 mm/min, bondline 1.5 mm, 2.5-3.0 mg/in² FERROCOTE® 61 MAL HCL; Cure condition: 163°C/30 minutes

[0076] The properties shown at Table C demonstrate that the XNBR-based adduct (in Example 4) provides equal or better performance when compared to the CTBN-based adduct and improves modulus retention at 80 °C.

[0077] Examples 5 and 6

[0078] As in the setup described in Examples 1 and 2 with the TCU set to 250 °F, 500 parts of Krynac X 146 are added to the mixer and masticated for five minutes. Subsequently 750 parts of Kukdo KD-214C epoxy is added over eight minutes to obtain a homogeneous mixture. Next the TCU setpoint is increased to 270 °F and an additional 750 parts of KD-214C is added over eight minutes. The TCU setpoint is then increased to 320 °F and mixing continues for 53 minutes. Next, the TCU setpoint is increased to 330 °F and mixing continues for 150 minutes. The material is then pulled out of the mixer and quickly cooled to yield a friable solid. The compositions of Examples 5 and 6 are shown below at Table D.

[0079] Table D

[0080] The adducts of Examples 5 and 6 are then formulated into foaming epoxy-based composition as shown below in Example 5 (comparative) and Example 6 (XNBR adduct) at Table E.

[0081]

[0082] Table E

[0083] Evaluation of the foaming epoxy-based compositions of Examples 7 and 8, cured at 163 °C for 30 minutes, yielded the following properties shown at Table F.

[0084] Table F

*0.030” EG60, test speed:254 mm/min, bondline 3 mm; **0.060” EG60, test speed: 50.4 mm/min, bondline 1.5 mm, 2.5-3.0 mg/in² FERROCOTE® 61 MAL HCL; Cure condition: 163°C/30 minutes

[0085] The previous examples demonstrate improved modulus retention with materials comprising the XNBR adduct, even when low amounts of adduct are used.

[0086] Examples 9 and 10

[0087] In the manner described in Examples 1 and 2, an adduct of the following composition is prepared with one addition. The thermoplastic polyvinyl butyral (PVB) is added after the YD-128 is incorporated and mixed for several minutes to ensure a homogeneous mixture. The mixture is then removed from the mixer and quickly cooled to room temperature to yield a friable solid. The following table G shows the compositions of Examples 9 and 10.

[0088] Table G

[0089] The solid adducts of Examples 9 and 10 are formulated into foaming epoxy-based compositions (in this case a pressure-sensitive adhesive) as shown below in Examples 11 and 12 in Table H.

[0090] Table H

[0091] Evaluation of the foaming epoxy-based compositions of Examples 11 and 12 yielded the following properties show at Table I.

[0092] Table I

*0.030” EG60, test speed:254 mm/min, bondline 3 mm; **0.060” EG60, test speed: 50.4 mm/min, bondline 1.5 mm, 2.5-3.0 mg/in² FERROCOTE® 61 MAL HCL; Cure condition: 163°C/30 minutes

[0094] The above examples demonstrate improved modulus retention in a foaming pressure sensitive adhesive thermoset

[0095] As used herein, unless otherwise stated, the teachings envision that any member of a genus (list) may be excluded from the genus; and/or any member of a Markush grouping may be excluded from the grouping. [0096] Unless otherwise stated, any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component, a property, or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that intermediate range values such as (for example, 15 to 85, 22 to 68, 43 to 51 , 30 to 32 etc.) are within the teachings of this specification. Likewise, individual intermediate values are also within the present teachings. For values which are less than one, one unit is considered to be 0.0001 , 0.001 , 0.01 , or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. As can be seen, the teaching of amounts expressed as "parts by weight" herein also contemplates the same ranges expressed in terms of percent by weight. Thus, an expression in the of a range in terms of at "'x' parts by weight of the resulting polymeric blend composition" also contemplates a teaching of ranges of same recited amount of "x" in percent by weight of the resulting polymeric blend composition."

[0097] Unless otherwise stated, all ranges include both endpoints and all numbers between the endpoints. The use of "about" or "approximately" in connection with a range applies to both ends of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", inclusive of at least the specified endpoints.

[0098] The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for ail purposes. The term "consisting essentially of to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, ingredients, components or steps herein also contemplates embodiments that consist of, or consist essentially of the elements, ingredients, components or steps.

[0099] Plural elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step might be divided into separate plural elements, ingredients, components or steps. The disclosure of "a" or "one" to describe an element, ingredient, component or step is not intended to foreclose additional elements, ingredients, components or steps.

[00100] It is understood that the above description is intended to be illustrative and not restrictive. Many embodiments as well as many applications besides the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the invention should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The omission in the following claims of any aspect of subject matter that is disclosed herein is not a disclaimer of such subject matter, nor should it be regarded that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

Claims

Claim 1: A solid, epoxy adduct comprising the reaction product of:

(i) a solid carboxylated nitrile rubber (XNBR); and

(ii) an epoxy functional resin.

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

Claim 3: The adduct of claim 1 , wherein a carboxylic acid content of the solid carboxylated nitrile rubber is less than 1% by weight.

Claim 4: The adduct of any of the preceding claims, wherein the solid carboxylated nitrile rubber (XNBR) is present in an amount of at least 10% by weight.

Claim 5: The adduct of the preceding claims, wherein the solid carboxylated nitrile rubber (XNBR) is a carboxylated cold polymerized butadiene acrylonitrile terpolymer.

Claim 6: The adduct in any of the preceding claims, wherein the epoxy functional resin for the adduction reaction comprises a solid epoxy resin.

Claim 7: The adduct in any of the preceding claims, wherein the epoxy functional resin for the adduction reaction comprises a liquid epoxy resin.

Claim 8: The adduct of any of the preceding claims, wherein the adduct is free of any carboxyl terminated butadiene acrylonitrile (CTBN) material.

Claim 9: The adduct of any of the preceding claims, wherein the adduct comprises polyvinyl butyral.

Claim 10: The adduct of claim 9, wherein the polyvinyl butyral is present in an amount of at least 5%, or even at least 10%. Claim 11 : The adduct of any of the preceding claims, wherein the adduct comprises at least two different epoxy-functional resins.

Claim 12: The adduct of any of the preceding claims, wherein the adduct comprises at least three different epoxy-functional resins.

Claim 13: The adduct of any of the preceding claims, wherein the adduct comprises a solvent.

Claim 14: The adduct of any of the preceding claims, wherein the adduct is free of any solvent.

Claim 15: The adduct of any of the preceding claims, wherein the adduct comprises a metal carbonate.

Claim 16: An epoxy-based composition comprising the adduct of any of claims 1 through 15.

Claim 17: The composition of claim 16, wherein the composition is foamable upon exposure to a stimulus.

Claim 18: The composition of claim 16, wherein the composition is foamable upon exposure to elevated temperatures (e.g., 120 °C to 200 °C).

Claim 19: The composition of any of claims 16 through 18, wherein the composition has an improved storage modulus (e.g., an improvement of at least 10%, at least 20%, or even at least 30%) as compared to a composition that includes a carboxyl terminated butadiene acrylonitrile (CTBN)-based adduct and no XNBR-based adduct.

Claim 20: The composition of any of claims 16 through 19, wherein the composition is free of any carboxyl terminated butadiene acrylonitrile (CTBN)-based adducts.

Claim 21 : The composition of any of claims 16 through 20, wherein the composition comprises a blowing agent, a curing agent, or both. Claim 22: The composition of any of claims 16 through 21 , wherein the composition comprises a polymeric particle.

Claim 23: The composition of any of claims 16 through 22, wherein the composition has adhesive properties.

Claim 24: The composition of any of claims 16 through 22, wherein the composition has sealing properties.

Claim 25: The composition of any of claims 16 through 22, wherein the composition has structural properties.

Claim 26: The composition of any of claims 16 through 22, wherein the composition is a pressure-sensitive adhesive.

Claim 27: The composition of any of any of claims 16 through 26, wherein the solid carboxylated nitrile rubber adduct provides for a tensile modulus as measured in accordance with ASTM D638 that is within 10% or less of the tensile modulus of the same composition with a carboxyl terminated butadiene acrylonitrile (CTBN)-based adduct.

Claim 28: The composition of any of any of claims 16 through 27, wherein the modulus of the composition at room 20 °C to 25 °C does not decrease by more than 60% when exposed to temperatures of more than 80 °C.

Claim 29: The composition of any of any of claims 16 through 28, wherein the volume expansion of the composition is greater with the solid carboxylated nitrile rubber adduct than with a carboxyl terminated butadiene acrylonitrile (CTBN)-based adduct.

Claim 30: A solid, epoxy adduct comprising the reaction product of:

(i) a solid carboxylated nitrile rubber (XNBR);

(ii) a first epoxy functional resin;

(iii) an optional second epoxy functional resin; and

(iv) a polyvinyl butyral additive.