WO2025255310A1 - Epoxy foams with polycarbonate as both curing and foaming agents - Google Patents

Abstract

A foamable material comprising at least one difunctional or multifunctional epoxy, at least one polycarbonate, at least one curing catalyst, and at least one foaming catalyst, wherein the polycarbonate material foams and cures the foamable material to form a foamed and cured material.

Description

EPOXY FOAMS WITH POLYCARBONATE AS BOTH CURING AND FOAMING AGENTS

CLAIM OF PRIORITY

[001] This application claims the benefit of the priority dates of United States Provisional Application Serial No. 63/656,475, filed June 5, 2024, the contents of this application is being incorporated by reference herein in its entirety and for all purposes.

FIELD OF INVENTION

[002] The present teachings relate generally to epoxy foams with polycarbonate as both curing and foaming agents.

BACKGROUND

[003] Heat activated foamable epoxy compositions have been widely used in various industries including aerospace, automotive, sporting goods, and other industrial sectors, due to their outstanding mechanical and adhesion properties. Foaming and curing agents can be compounded into a formulated composition that will be activated at elevated temperatures to form a crosslinked and foamed network.

[004] Common latent curatives include dicyandiamide, urea, hydrazide, boron trifluoride amine complex, and other related compounds. Nitrogen-containing curatives often generate ammonia or amine by-products that can produce a strong odor when the material is being cured at elevated temperatures. Similarly, nitrogen-containing chemical foaming agents such as azodicarbonamide (Tradename Celogen AZ) or benzenesulphonyl hydrazide (Tradename Celogen OT) also impart odor to foamed products via decomposition products created during heat activation.

[005] The United Nations Economic Commission for Europe has been promoting its guidance on car interior air quality standards aiming to reduce the interior odor. Other organizations are interested in reducing odor as well, particularly in Asia, where complaints concerning unpleasant odors or harmful emissions in vehicle interiors seem to be especially prevalent. As vehicle interior air quality regulation has been adopted by more and more automotive manufacturers in Europe and Asia, there is a demand for materials that meet this requirement, with particular difficulty associated with chemical systems that are reactive, such as adhesives and sealants.

[006] Polycarbonate has been used as foaming agent in place of azodicarbonamide in epoxy foams. Although foaming is a result of odorless carbon dioxide generated from polycarbonate decomposition, these compositions may still have a strong odor after curing due to the ammonia by-product from the curatives (i.e., dicyandiamide and urea). International Publication No. WO 2023/091662 addresses the use of polycarbonate as a foaming agent, but in combination with typical latent curing agents.

[007] Polycarbonate (PC) has been found to react with other materials including epoxides and hydroxyls/phenols via transesterification mechanism and thus may be used as low odor curatives for epoxy-based thermoset materials. International Application No. PCT/US2024/020682 addresses the use of polycarbonate as a curative, however only minimal foaming (<100% volumetric expansion) was achieved and challenges remained for increased and consistent volumetric expansion.

[008] The present teachings seek to provide epoxy foams with polycarbonate as both curing and foaming agents in the absence of common curatives including dicyandiamide, hydrazide, acid anhydride, and boron trifluoride amine complex and common chemical foaming agents like azodicarbonamide. Given the competing foaming and curing reactions of polycarbonate, challenges remain in achieving simultaneous high extent of cure and high foaming percentage in epoxy foams without dicyandiamide and azodicarbonamide.

SUMMARY OF INVENTION

[009] The teachings herein are directed to a one-component heat-activated epoxy foam comprising one or more epoxy resins, polycarbonate, a catalyst for polycarbonate decomposition to produce carbon dioxide, and a catalyst for the reaction between epoxy and polycarbonate. [0010] The material may contain polyol and/or phenols.

[0011] The material may contain tougheners, thermoplastic resins, and/or polymeric core shell particles.

[0012] The material may contain constituents that do not melt in the compounding or normal process conditions like moisture scavengers, fibers, and anticorrosive additives.

[0013] The material may have a foaming percentage from 100% to 300%, when cured at 140- 200°C for 30 minutes.

[0014] The material may be injection moldable, extrudable, pumpable, and in the form of pressure sensitive tapes.

[0015] The material may comprise polycarbonate in the range of about 5% to about 60% by weight.

[0016] The material may comprise a curing catalyst for transesterification in the range of about 0.01% to about 10% by weight. [0017] The material may comprise a catalyst for foaming in the range of about 0.01% to about 10% by weight

[0018] The material may comprise a moisture scavenger in the range of about 0% to about 40% by weight.

[0019] The material may comprise a toughener in the range of about 0% to about 40% by weight. [0020] The material may comprise polymeric particles in the range of about 0% to about 30% by weight.

[0021] The material may comprise a thermoplastic resin in the range of about 0% to about 30% by weight.

[0022] The material may comprise an anticorrosive additive in the range of about 0.5% to about 10% by weight.

[0023] The polycarbonate resins may have a melt index ranging from about 2 to about 60 g/10 min (300 °C, 1 .2 kg load) and molecular weight from about 5,000 to about 300,000.

[0024] The polyol may be aliphatic or aromatic polyester or polyether or polycarbonate polyols.

[0025] Phenols may include hydroquinone, resorcinol, catechol, various diphenols including bisphenol A, bisphenol F, bisphenol E, bisphenol AP, bisphenol Z, bisphenol M, bisphenol P, bisphenol G, bisphenol BP, novolac phenols or any combination thereof.

[0026] The curing or transesterification catalyst may include quaternary ammonium salts, quaternary phosphonium salts, Lewis acids, metal oxides, phosphines, solid strong acids, or any combination thereof.

[0027] The catalyst for foaming may include amines and nitrogen containing compound, metal chlorides, metal phosphate ester salts, metal stearate salts, metal carbonates, metal hydroxides, metal acetylacetonates, titanate complexes, metal triflates, organophilic phyllosilicates, and other related compounds.

[0028] The reactive toughener may be an adduct of rubber and epoxy resin. The polymeric particles may include core modifiers of polybutadiene, styrene-butadiene rubber, or a combination thereof.

[0029] The polymeric particles may include core/shell rubber particles averaging about 100-200 nm in size, and preferably may be free of agglomerated particles.

[0030] The material may include one or more constituents that do not melt in compounding or normal process conditions, which may be selected from silica, diatomaceous earth, glass, clay (e.g., including nanoclay), glass beads or bubbles, glass, carbon or ceramic fibers, nylon, aramid or polyamide fibers (e.g., Kevlar), pyrophyllite, sauconite, saponite, nontronite, wollastonite, montmorillonite, or any combination thereof. [0031] The material may include an anticorrosive additive comprising zinc compound.

[0032] The moisture scavenger may include calcium oxide, molecular sieves, vinyltrimethoxy silane, zeolite, oxazolidines, or any combination thereof.

[0033] The material may be substantially free of dicyandiamide, urea, hydrazide, boron trifluoride amine complex, anhydride, azodicarbonamide, benzenesulphonyl hydrazide, organic acids, inorganic carbonates, thermoplastic microspheres, or any combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 shows a graph depicting storage and loss modulus as temperature increases.

DETAILED DESCRIPTION

[0035] 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.

[0036] Percentages herein refer to weight percent, unless otherwise indicated.

[0037] Unless expressly stated otherwise, the terms "epoxy resin" and "epoxy" are used interchangeably.

[0038] Unless expressly stated otherwise, the terms "polycarbonate resin" and "polycarbonate" are used interchangeably.

[0039] Unless expressly stated otherwise, molecular weight of polymeric species is preferably expressed as weight average molecular weight (Mw), preferably determined by GPC.

[0040] Unless expressly stated otherwise, all references to standards such as ASTM preferably refer to the version that is officially valid on January 1 , 2024.

[0041] Melt index is preferably determined in accordance with ASTM D1238.

[0042] T-peel strength is preferably determined in accordance with ASTM D1876.

[0043] The material of the present teachings may be applied to various articles of manufacture for adding structural integrity to portions or members of the articles. Examples of such articles of manufacture include, without limitation, household or industrial appliances, furniture, storage containers, buildings, structures, or the like. The material may be applied to portions of transportation vehicles including boats, trucks, trains, airplanes, automotive vehicles or the like. The material may be utilized in an automotive vehicle, such as with body or frame members (e.g., a vehicle frame rail) of the automotive vehicle.

[0044] The present teachings are directed to the use of polycarbonate to prepare heat activatable epoxide-containing foams in the absence of common curing agents including dicyandiamide, hydrazide, acid anhydride, and boron trifluoride amine complex and also in the absence of common chemical foaming agents like azodicarbonamide. Exclusion of the above-mentioned curing and foaming agents enables creation of epoxy foams with minimal odor both prior to, during, and after cure.

[0045] Polycarbonates are a family of thermoplastic polymers characterized by high strain-to- failure combined with high strength, stiffness, and impact resistance. They have not traditionally been used in thermosetting compositions. They contain carbonate groups in their chemical structure which are known to react with epoxies, polyols, and phenols by transesterification reactions (scheme 1 and 2). Polycarbonate can also decompose via thermal hydrolysis mechanism to release carbon dioxide at elevated temperatures, which has been adopted to produce foams (WO2023091662A1). The present teachings are directed to demonstrate the use of these reactions as crosslinking and foaming mechanisms for one-component epoxy-based heat activated foams. The present teachings also aim at revealing key factors for altering the material properties (i.e., glass transition temperature (Tg), lap shear strength, peel strength, strain-to- failure, and volume expansion) with polycarbonates as both curatives and foaming agents.

Scheme 1. Chemical structure of polycarbonate

Scheme 2. Reactions between carbonates and epoxides, hydroxyls, and phenols, a. transesterification between carbonates and epoxides; b. transesterification between carbonates and hydroxyls; c. Transesterification between carbonates and phenols.

[0046] The material may include at least one type of polycarbonate resin with a melt index ranging from about 3 to about 35 g/10 min and molecular weight from about 10,000 to about 100,000 Daltons. Non-limiting examples of polycarbonate resins that may be used are Lexan from Sabie, Hylex from Ravago Manufacturing Americas, CALIBRE from Trinseo, and TRI REX from Samyang Corporation. The polycarbonate may be included in a percentage of up to about 50% by weight. It may be approximately at least about 2% by weight, more typically at least about 10% by weight, more typically at least about 20% by weight. It may be approximately about 50% or less by weight, more typically about 40% or less by weight, more typically about 30% or less by weight, and even more typically 25% or less by weight. In order to enhance the compounding of the material, it is preferred that the polycarbonate resin be combined with other composition constituents as a solution. While any solvent may be used to decrease incorporation temperature during mixing, it is particularly preferred to use a low molecular weight epoxy resin as the solvent so that the solvent can react into the composition upon activation. Polycarbonate can also be ground into fine powders for easy incorporation.

[0047] The material described herein may include a difunctional or multifunctional epoxy resin, to react with polycarbonate by transesterification to form the polymeric matrix of the epoxy foams. Both liquid and solid epoxy resins may be used in combination to tune the viscosity of the material. Exemplary bifunctional epoxy resins may be DER 331 from Olin Corporation, EpotecSYDF 172LV (DGEBF), available from Aditya Birla and DER 664 from Olin Corporation. An epoxy resin also may also be added to the material to increase the adhesive capability and flexibility of the material. A silane modified epoxy resin may aid in allowing the material to adhere to non-ferrous metals, such as to aluminum, as well as improving adhesion after environmental exposure (i.e. , humidity, salt spray). The silane modified epoxy resin may be a reaction product between at least one epoxy resin and a silane compound. An example of a suitable silane-modified epoxy resin is Epokukdo KSR-177 (di-functional silane-modified epoxy resin) available from Kukdo Chemical. Suitable flexible epoxy resins include Epiol DE202 from Kukdo Finechem Co., Ltd. and DER 732 from Olin Corporation. Multifunctional epoxy resins may be added to improve the glass transition temperature of the epoxy foams. Examples may include Epokukdo YDCN-500-80P and Epokukdo KDCP-130 from Kukdo Finechem Co., Ltd., Epalloy 8208 and Epalloy 9000 from Huntsman International LLC., and other related compounds. Various mixtures of several different epoxy resins may be employed to achieve desirable properties for an intended purpose.

[0048] The weight percentage for the total epoxy content may be approximately at least about 20% by weight, more typically at least about 30% by weight, more typically at least about 40% by weight. It may be approximately about 80% or less by weight, more typically about 70% or less by weight, more typically about 60% or less by weight, and even more typically 50% or less by weight.

[0049] The material may include a difunctional or multifunctional polyol or phenol, which reacts with both epoxy resins and polycarbonate at high temperatures in the presence of a catalyst. Difunctional phenols may act as chain extenders for epoxy resins, leading to longer chain length and thus greater possibility of achieving a composition capable of deforming plastically. Difunctional polyols have been found useful to improve material peel resistance as a result of the longer chain oligomers reducing cross-link density.

[0050] In a differing approach, multi-functional polyols may be utilized to increase the crosslink density of the epoxy foam material. Although polyols and phenols are not necessary to crosslink epoxy resins, they may be used as bridging molecules to link epoxy to polycarbonate due to the reactivity to both materials, consequently leading to higher crosslinking density and glass transition temperature. Examples of polyols include aliphatic and aromatic polyester, polyether, and polycarbonate polyols, such as Resonance aliphatic and aromatic polyols from Bakelike and Eternacoll polyols from UBE Industries Ltd. Examples of phenols include hydroquinone, resorcinol, catechol, bisphenol A, bisphenol F, bisphenol E, bisphenol AP, bisphenol Z, bisphenol M, bisphenol P, bisphenol G, bisphenol BP, and other related compounds. Polyphenols with functionality greater than two may also be used to improve crosslinking density for high temperature performance. Exemplary polyphenols include Tannin, Ellagic acid, Theaflavin-3- gallate, and phenolic resin, such as Akrochem SP-1045 from Akrochem Corporation, Irganox 1010 and Irganox 1076 from BASF, Plenco 14772 and 15051 from Plastic Engineering Company. [0051] Polyols and phenols may be approximately at least about 1% by weight, more typically at least about 5% by weight, more typically at least about 10% by weight. It may be approximately about 30% or less by weight, more typically about 25% or less by weight, more typically about 20% or less by weight, and even more typically 15% or less by weight.

[0052] A curing catalyst may be used to activate the transesterification of polycarbonate to provide sufficient crosslinking. Quaternary ammonium salts, quaternary phosphonium salts, phosphines, Lewis acids, metal oxides, and solid strong acids may be suitable catalysts for this reaction. Examples of quaternary ammonium and phosphonium salt may be tetraethylammonium bromide, tetrabutylammonium bromide, tetramethylammonium chloride, tetraethylphosphonium chloride, tetrabutylphosphonium chloride, and other related compounds. The catalyst may also be quaternary ammonium functionalized particles such as Garamite treated nano-clay products by BYK and quaternary ammonium functionalized ion exchange resin such as Dowex strong base resin available from Dupont. The catalyst may also be phosphines like triphenylphosphine, trinaphthylphosphine, or tritolylphosphine. Examples of Lewis acid catalysts include SnCL, Si(OEt)3(CH2)2SnCh, TiCL, TiCh, Ti(O-isopropyl)4, Cp2TiCh, Smh, VOCh, AICI3, dimethyltin dithioglycolate, dibutyltin dilaurate, dioctyltin dithioglycolate, and other related compounds. Metal oxides that may be utilized include TiO2, TiO2/SiO2, PbO, PbO/MgO, PbO/SiO2, PbO-r-AhOs, PbO/TiO₂, OO₃, MOO3/AI2O3, MoO₃/CaO, MgO, Mg₆Fe(OH)i₆CO3, , Mg-AI-hydrotalcite, and/or SnO₂. Solid strong acids that may be included are sulfonated inorganic particles or ion exchange resins including Amberlyst and Amberlite materials available from Dupont and Dowex products from Lenntech. The catalyst may be present in an amount approximately at least about 0.02% by weight, more typically at least about 0.1 % by weight, more typically at least about 0.2% by weight. It may be approximately about 10% or less by weight, more typically about 5% or less by weight, and even more typically about 2% or less by weight.

[0053] The material may include a catalyst for polycarbonate decomposition to produce carbon dioxide. Examples of suitable activators include but are not limited to amines and nitrogen containing compounds. Examples of amines and nitrogen containing compounds include tertiary amines, imidazoles, amine adducts, triazoles, amides, urea, and ammonium derivatives. Examples of other suitable decomposition promoting agents include metal chlorides, blocked isocyanates, metal phosphate ester salts, metal stearate salts, metal carbonates, metal hydroxides, metal acetyl aceto nates, titanate complexes, metal tritiates, organophilic phyllosilicates, and other Lewis acids. The choice and quantity of decomposition agent may be chosen to meet foaming temperature and volume expansion requirements while maintaining low odor. Foaming activator may be approximately at least about 0.1 % by weight, more typically at least about 0.5% by weight, more typically at least about 2% by weight. It may be approximately about 10% or less by weight, more typically about 5% or less by weight, and even more typically about 3% or less by weight.

[0054] In another aspect, a single catalyst may be utilized for both transesterification and foaming. An example of a suitable material may include: choline chloride.

[0055] The material may include at least one type of polymeric particle. Such polymeric particles may be utilized to improve fracture toughness (Gic), peel resistance and impact resistance of the foamed material. As used herein, the term “polymeric particle” is defined as a particle including a polymeric material. 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 2%, more typically at least 3%, even more typically at least 6%, still more typically at least 10% and even still more typically at least 20% by weight of the material and also preferable for the polymeric particle to be less than 90%, more typically less than 40% and even more typically less than 30% by weight of the material, although higher or lower amounts may be used in particular embodiments.

[0056] 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. [0057] The shell portion may be polymerized from methyl acrylates such as methyl methacrylate and optionally other alkyl (meth)acrylates and (meth)acrylates, such as ethyl, butyl, or mixtures thereof. Up to 40 percent by weight or more of the shell monomers may be styrene, vinyl acetate, vinyl chloride, and the like. Additional core-shell graft copolymers useful in embodiments of the present teachings are described in United States 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. 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 PBd (polybutadiene) or a polybutadiene copolymer rubber. The MBS graft copolymer resin may generally have a SBR (styrene-butadiene rubber) core and a shell of acrylic polymer or copolymer. Examples of other useful core-shell graft copolymer resins include, PBd (polybutadiene), 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.

[0058] Examples of useful polymeric particles include but are not limited to those sold under the tradename, Kane Ace™, commercially available from Kaneka Americas Holding, Inc, Clearstrength from Arkema, and Paraloid from Dow. Particularly preferred grades of Kane Ace™ are sold under the designations MX-134 and MX-267. The polymeric particles may average no less than 50 nm and no greater than 300 nm in size.

[0059] Epoxy functionalized elastomers may be included and may provide additional modifications to the properties of the foamed material. Epoxy functionalized elastomers may be present in the range of about 1% to about 40% by weight. The elastomer is often a product of epoxy resins and elastomers selected from, carboxyl-terminated butadiene-acrylonitrile (CTBN), amine-terminated butadiene-acrylonitrile (ATBN), carboxylated nitrile rubber (XNBR) and polysulfide or any combination thereof. Exemplary XNBR include Krynac X146, Krynac X160 from Arlanxeo, and Nipol 1472X from Zeon Corp.

[0060] The material may additionally include high molecular weight polymers to improve the thermoplastic-like nature of the foam. The high molecular weight polymers may modify properties including strain-to-failure, peel strength, and impact resistance of epoxy materials. An example of a high molecular weight polymer is polyvinyl butyral which is prepared from polyvinyl alcohol and butyraldehyde. Another example of high molecular weight polymer is thermoplastic epoxy resin which is a product of difunctional epoxy resins and chain extenders (e.g., mono-primary amine). Examples of chain extenders include mono-primary amines, di-secondary amines, and di- mercaptans. As one non-limiting example, mono-primary amines may include 1-naphthylamine, 2-naphthylamine, ethanolamine, phenethylamine, oleylamine, or a combination thereof. Examples of suitable di-mercaptans include DM DO (2,2'-(Ethylenedioxy)diethanethiol) from Arkema Innovative Chemistry, and Thiocure GDMP ((Ethylene glycol bis(3-mercaptopropionate)) from Bruno Bock.

[0061] The high molecular weight polymer may be included in an amount of up to about 20% by weight. It may be approximately at least about 0.2% by weight, more typically at least about 1% by weight, more typically at least about 3% by weight.

[0062] The material may include constituents that do not melt in the compounding or normal process conditions. The constituents may be in shapes of spheres, needles, and plates. Examples are organic or non-organic additives which differ from the polymeric matrix to improve adhesive properties, change thixotropic properties, improve moisture resistance, improve corrosion resistance, and reduce cost. These may include silicates such as those sold under the trade names of Garamite® and Satintone® clays, mica, talc, clays, wollastonite under the trade names of Nyglos®, Vansil® and Wollastocoat®, calcium carbonate, calcium oxide, calcium sulfate, hollow glass and polymer spheres, carbon black, barium sulfate, zinc phosphate, and graphite. The material may include rheological modifiers which may be selected from silica under trade names of Aerosil® and Cab-o-sil®, aramid or polyamide fibers (e.g., Kevlar), or a combination thereof. Other additives, agents or performance modifiers may also be included in the material as desired, including but not limited to a UV resistant agent, a flame retardant, a heat stabilizer, a colorant, a processing aid, a lubricant or the like.

[0063] It is possible that the specific combination and relative amounts of one or more materials described herein, may assist in providing improved values for one or more of T-peel strength, or lap shear strength.

[0064] Certain materials formed in accordance with the present teachings have exhibited strain- to-failure greater than about 1%, greater than about 2%, and even possibly greater than about 3% when determined in accordance with ASTM D638 Type IV test method with 5 mm/min crosshead speed. The strain-to-failure was measured by using an extensiometer to record the deformation that is then used to calculate the material strain.

[0065] Certain materials formed in accordance with the present teachings have exhibited lap shear strength greater than about 1 Pa, greater than about 2 MPa, and even possibly greater than 3 MPa when determined in accordance with ASTM D5868 with 50.4 mm/min crosshead speed and 3 mm bondline. [0066] Certain materials formed in accordance with the present teachings have exhibited T peel strength greater than about 2 N/mm, greater than about 3 N/mm, and even possibly greater than 4 N/mm when determined with 254 mm/min crosshead speed and 1.5 mm bondline.

[0067] Certain materials formed in accordance with the present teachings have exhibited glass transition (Tg) of greater than 60 degrees Celsius, greater than 70 degrees Celsius, and even greater than 90 degrees Celsius when determined by ASTM D7028-07. The glass transition temperature determined by this test method (referred to as Dynamic Mechanical Analysis Tg or "DMA Tg") may not be the same as that reported by other measurement techniques (i.e. , peak of tan delta) on the same test specimen. The test method is commonly used to determine upper use temperature for composite materials.

[0068] Certain materials formed in accordance with the present teachings have volume expansion of greater than 100, greater than 200, and even greater than 300%. Volume expansion is calculated according to the equation below.

[0069] For exemplary purposes, Table A is produced below to illustrate three exemplary formulations for forming the one component heat activated foams that cure and expand by polycarbonate. Notably, all compositions present no undesirable amine or amine-like odor during and after bake in contrast to foams containing DICY and azodicarbonamide.

[0070] Table A

1 . 0.060” EG60, test speed: 50.4 mm/min, bondline 3 mm, 2. 0.030” EG60, test speed:254 mm/min, bondline 1 .5 mm; 3. ASTM D638 Type IV test method with 5 mm/min crosshead speed; 4. ASTM D7028-07 storage modulus inflection point; 5. ASTM D7028-07 peak of Tan delta.

[0071] Volume expansion is a typical property that has been used to characterize the extent of foaming. It indicates the capability of foams to fill a cavity. When materials expand upon heat, their dimension increases in all directions. Depending on the composition, some expand more in the lateral plane while others prefer to rise vertically. In contrast to volume expansion, vertical rise percentage provides more relevant information for applications where the material is expected to jump a gap and bond to the mating surface.

[0072] Since polycarbonate acts as both curing and foaming agents, competing reactions occur when the material is exposed to elevated temperatures (i.e., 285 and 325 °F). Decomposition of polycarbonate releases carbon dioxide for foaming and transesterification of polycarbonate contributes to crosslinking. No prior art has demonstrated how to utilize these competing reactions to achieve simultaneous high volume expansion and full cure. The present teachings aim at providing compositions that meet both requirements, while retaining reactive latency prior to reaction.

[0073] All foams in the present teachings are cured under two conditions (i.e., 285 °F for 25 min and 325 °F for 30 min). As shown in Table A, polycarbonate foaming and curing can both be activated at these two temperatures. All foams show high volume expansion (i.e., 130-320%), lap shear strength (i.e., 1.6-2.6 MPa), and T peel strength (1.9-3.8 MPa). Higher temperature (i.e.,

1 . 0.060” EG60, test speed: 50.4 mm/min, bondline 3 mm, 2. 0.030” EG60, test speed:254 mm/min, bondline 1 .5 mm; 3. ASTM D638 Type IV test method with 5 mm/min crosshead speed; 4. ASTM D7028-07 storage modulus inflection point; 5. ASTM D7028-07 peak of Tan delta.

[0075] Polycarbonate has a great influence on material properties given it is the key ingredient for both foaming and curing. As shown in Table B, sample 2, 4, and 5 contain 13.5, 16.25, and 21.25% polycarbonate, respectively. Increase in polycarbonate content significantly improves the glass transition temperature (Tg) of cured materials, suggesting more reactive sites per unit volume. For example, sample 2 has a Tg of 66.5 °C and 78.6 °C when cured at 285 °F and 325 °F, while Tg of sample 4 rises to 80.4 °C and 90.0 °C when cured at 285 °F and 325 °F, respectively. As such, greater polycarbonate content may be desirable for application where high temperature (i.e., 80 °C) performance is needed. Notably, increased polycarbonate does not always lead to higher expansion. Samples 2, 4, and 5 in Table B have comparable volume expansion. Although more polycarbonate may generate greater volume of carbon dioxide, it is not the only factor dictating volume expansion. Stiffness of the material during foaming and gastrapping capability also play an important role.

[0076] Table C

1. 0.060" EG60, test speed: 50.4 mm/min, bondline 3 mm; 2. 0.030" EG60, test speed:254 mm/min, bondline 1.5 mm; 3. ASTM D638 Type IV test method with 5 mm/min crosshead speed; 4. ASTM D7028-07 storage modulus inflection point; 5. ASTM D7028-07 peak of Tan delta.

[0077] Phenol-functionalized compounds are used as co-curing agents for polycarbonate curing. Although polyols and phenols are not necessary to produce crosslinking epoxy resins, they may be used as bridging molecules to link epoxy to polycarbonate due to the reactivity to both materials, consequently leading to higher crosslinking density and glass transition temperature. Table C includes formulations with difunctional or multifunctional phenols and aromatic polyols. In comparison to difunctional phenol (i.e., bisphenol A in sample 2), multifunctional phenols in sample 6 and 7 contribute to improved glass transition temperature due to increased crosslinking density. For example, sample 7 exhibits glass transition temperatures of approximately 15 degrees higher than sample 2 when cured at both temperatures. However, multifunctional phenols lead to rapid acceleration in curing, which suppresses the volume expansion drastically. Volume expansion for both sample 6 and 7 dropped below 100%.

[0078] Table D ( Elongation³ (%) (

( Tg⁴(°C) I 66.5 | 78.6 | 85.6 ( 93.4 |

( Tg⁵(°C) I 81.7 ( 91.4 | 98.8 | 106.4 |

1. 0.060" EG60, test speed: 50.4 mm/min, bondline 3 mm; 2. 0.030" EG60, test speed:254 mm/min, bondline 1.5 mm; 3. ASTM D638 Type IV test method with 5 mm/min crosshead speed; 4. ASTM D7028- 07 storage modulus inflection point; 5. ASTM D7028-07 peak of Tan delta.

[0079] In addition to curing agents (i.e., polycarbonate and phenols), amount of catalyst for polycarbonate transesterification can be utilized to improve glass transition temperature of cured foams. As shown in Table D, sample 8 with increased tetrabutylphosphonium bromide shows higher Tg than sample 2 when cured at both 285 °F and 325 °F. As expected, volume expansion is significantly reduced due to accelerated curing. Depending on the application requirement, the amount of catalyst can be tuned to achieve desirable Tg and volume expansion.

[0080] Table E

1. 0.060" EG60, test speed: 50.4 mm/min, bondline 3 mm: 2. 0.030" EG60, test speed:254 mm/min, bondline 1.5 mm; 3. ASTM D638 Type IV test method with 5 mm/min crosshead speed; 4. ASTM D7028- 07 storage modulus inflection point; 5. ASTM D7028-07 peak of Tan delta.

[0081] Table F

1. 0.060" EG60, test speed: 50.4 mm/min, bondline 3 mm; 2. 0.030" EG60, test speed:254 mm/min, bondline 1.5 mm: 3. ASTM D638 Type IV test method with 5 mm/min crosshead speed; 4. ASTM D7028-07 storage modulus inflection point; 5. ASTM D7028-07 peak of Tan delta.

[0082] Thermoplastic additives are used to replace low Tg toughener (i.e., rubber/epoxy adduct) aiming at improving glass transition temperature while maintaining or improving the peel strength of cured foams. Tables E and F demonstrate the impact of polyvinyl butyral (PVB) and thermoplastic epoxy resin on the material performance. Sample 9 and 3 contain 5% PVB and thermoplastic epoxy resin, respectively, in comparison to their respective controls (i.e., sample 2 and sample 3). Tg is improved in both cases by replacing rubber/epoxy adduct with thermoplastic additives. Additionally, lap shear strength and T peel strength have also been significantly improved for both sample 9 and 3 when cured at 325 °F for 30 min.

[0083] Table G

[0084] Table G shows the aging of sample 3 in comparison to a foamable epoxy composition containing DICY and azodicarbonamide. Decrease in volume expansion is a typical characteristic of foamable epoxy compositions associated with long time exposure to elevated temperature. Lower percentage loss in volume expansion suggests reduced sensitivity to exposure conditions. In the present teachings, accelerated aging (i.e., 3 days at 43 °C and 54 °C) is performed to demonstrate the latency of epoxy compositions cured and foamed by PC (i.e., sample 3). After 3 days aging at 43 °C and 54 °C, sample 3 shows 0% and 15% loss in volume expansion when baking at 325 °F for 30 min, a significant improvement compared to the foamable composition containing DICY and azodicarbonamide.

[0085] 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.

[0086] 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."

[0087] Unless otherwise stated, all ranges include both endpoints and all numbers between the endpoints, he 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.

[0088] The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all 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.

[0089] 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.

[0090] 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

1. A foamable material comprising:

(i) at least one difunctional or multifunctional epoxy;

(ii) at least one polycarbonate,

(iii) at least one curing catalyst; and

(iv) at least one foaming catalyst; wherein the polycarbonate material foams and cures the foamable material to form a foamed and cured material.

2 The foamable material of claim 1 , wherein the at least one difunctional or multifunctional epoxy includes 2 or more difunctional or multifunctional epoxies.

3 The foamable material of claim 1 or claim 2, wherein the at least one polycarbonate includes two or more polycarbonates.

4 The foamable material of any of the preceding claims, wherein the foamable material includes one or more polyol and/or phenol materials.

5 The foamable material of any of the preceding claims, wherein the foamable material includes one or more tougheners.

6 The foamable material of any of the preceding claims, wherein the foamable material includes one or more polymeric core shell particles.

7 The foamable material of any of the preceding claims, wherein the foamable material includes one or more thermoplastic resins.

8 The foamable material of any of the preceding claims, wherein the foamable material includes one or more moisture scavengers.

9 The foamable material of any of the preceding claims, wherein the foamable material includes one or more fibers.

10 The foamable material of any of the preceding claims, wherein the foamable material includes one or more anticorrosive additives.

11 The foamable material of any of the preceding claims, wherein the at least one polycarbonate is present in an amount of about 5% to about 60% by weight based on a total weight of the foamable material.

12 The foamable material of any of the preceding claims, wherein the at least one curing catalyst is present in an amount of about 0.01% to about 10% by weight based on a total weight of the foamable material.

13. The foamable material of any of the preceding claims, wherein the at least one foaming catalyst is present in an amount of about 0.01% to about 10% by weight based on a total weight of the foamable material.

14. The foamable material of any of the preceding claims, including at least one moisture scavenger present in an amount of about 0% to about 40% by weight based on a total weight of the foamable material.

15. The foamable material of any of the preceding claims, including at least one toughener present in an amount of about 2% to about 40% by weight based on a total weight of the foamable material.

16. The foamable material of any of the preceding claims, including at least one polymeric core shell particle present in an amount of about 2% to about 30% by weight based on a total weight of the foamable material.

17. The foamable material of any of the preceding claims, including one or more fibers present in an amount of about 0.1% to about 5% by weight based on a total weight of the foamable material.

18. The foamable material of any of the preceding claims, including at least one anticorrosive additive present in an amount of about 0.5% to about 10% by weight based on a total weight of the foamable material.

19. The foamable material of any of the preceding claims, wherein the at least one polycarbonate has a melt index ranging from 2 to 60 g/10 min as measured by ASTM D-1238 and molecular weight from 5,000 to 300,000.

20. The foamable material of any of the preceding claims, including one or more polyols that are aliphatic or aromatic polyester, polyether or polycarbonate polyols.

21. The foamable material of any of the preceding claims, including one or more phenols selected from the group consisting of: hydroquinone, resorcinol, catechol, bisphenol A, bisphenol F, bisphenol E, bisphenol AP, bisphenol Z, bisphenol M, bisphenol P, bisphenol G, bisphenol BP, and combinations thereof.

22. The foamable material of any of the preceding claims, wherein the at least one curing catalyst is selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts, phosphines, Lewis acids, metal oxides, phosphines, solid strong acids, and any combination thereof.

23. The foamable material of any of the preceding claims, wherein the at least one foaming catalyst is selected from the group consisting of amines and nitrogen containing compounds, metal chlorides, blocked isocyanates, metal phosphate ester salts, metal stearate salts, metal carbonates, metal hydroxides, metal acetylacetonates, titanate complexes, metal tritiates, organophilic phyllosilicates, Lewis acids, and any combination thereof.

24. The foamable material of any of the preceding claims, including one or more moisture scavengers selected from the group consisting of calcium oxide, molecular sieves, vinyltrimethoxy silane, zeolite, oxazolidines, and any combination thereof.

25. The foamable material of claim of any of the preceding claims, including one or more tougheners comprising an adduct of rubber and epoxy resin.

26. The foamable material of any of the preceding claims, including one or more polymeric core shell particles comprising core modifiers of polybutadiene, styrene-butadiene rubber, or a combination thereof.

27. The foamable material of any of the preceding claims, including one or more polymeric core shell particles comprising core/shell rubber particles averaging about 100-200 nm in size.

28. The foamable material of any of the preceding claims, including one or more polymeric core shell particles that are substantially free of agglomerated particles.

29. The material of any of the preceding claims, including one or more fibers comprising an aramid fiber.

30. The foamable material of any of the preceding claims, including one or more anticorrosive additives comprising a zinc compound.

31. The foamable material of any of the preceding claims, wherein the material is substantially free of dicyandiamide, urea, hydrazide, boron trifluoride amine complex, anhydride, azodicarbonamide, benzenesulphonyl hydrazide, organic acids, inorganic carbonates, thermoplastic microspheres, or any combination thereof.

32. The foamable material of any of the preceding claims, wherein the material has a glass transition temperature (Tg) of at least about 80 °C as measured by ASTM D7028-07.

33. A foamed material comprising:

(i) at least one difunctional or multifunctional epoxy material;

(ii) at least one polycarbonate,

(iii) a catalyst, the catalyst acting as a curing and foaming catalyst; wherein the polycarbonate material foams and cures the foamed material.

34. The foamed material of claim 33, wherein the at least one polycarbonate includes two or more polycarbonates.

35. The foamed material of claim 33 or claim 34, wherein the at least one polycarbonate is present in an amount of about 5% to about 60% by weight based on a total weight of the foamable material.

36. The foamed material of any of claims 33 through 35, wherein the at least one polycarbonate has a melt index ranging from 2 to 60 g/10 min as measured by ASTM D-1238 and molecular weight from 5,000 to 300,000.

37. The foamed material of any of claims 33 through 36, including one or more polyols that are aliphatic or aromatic polyester, polyether or polycarbonate polyols.

38. The foamed material of any of claims 33 through 37, including one or more phenols selected from the group consisting of: hydroquinone, resorcinol, catechol, bisphenol A, bisphenol F, bisphenol E, bisphenol AP, bisphenol Z, bisphenol M, bisphenol P, bisphenol G, bisphenol BP, and combinations thereof.

39. The foamed material of any of claims 33 through 38, wherein the at least one curing catalyst is selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts, phosphines, Lewis acids, metal oxides, phosphines, solid strong acids, and any combination thereof.

40. The foamed material of any claims 33 through 39, wherein the at least one foaming catalyst is selected from the group consisting of amines and nitrogen containing compounds, metal chlorides, blocked isocyanates, metal phosphate ester salts, metal stearate salts, metal carbonates, metal hydroxides, metal acetylacetonates, titanate complexes, metal triflates, organophilic phyllosilicates, Lewis acids, and any combination thereof.

41. The foamed material of any of claims 33 through 40, wherein the material is substantially free of dicyandiamide, urea, hydrazide, boron trifluoride amine complex, anhydride, azodicarbonamide, benzenesulphonyl hydrazide, organic acids, inorganic carbonates, thermoplastic microspheres, or any combination thereof.

42. The foamed material of any of claims 33 through 41 , wherein the material has a glass transition temperature (Tg) of at least about 80 °C as measured by ASTM D7028-07.

Get DMA plot to add as figure and potentially add alt Tg values

Structural foam

Claim expansion rate of x-y and Tg of x-y