Abstract: A process for preparing a curing agent for epoxy resins, in which an amine mixture including at least one parent amine of the formula (I) and at least one alkylated amine of the formula (II) is reacted or adducted with at least one glycidyl ether of the formula (III). The amine mixture is especially a reaction mixture from the partial alkylation of the amine of the formula (I). The process described enables, with low energy expenditure and high space-time yield, curing agents of low odor, low toxicity, low viscosity and high reactivity for epoxy resins and epoxy resin products that cure rapidly at ambient temperatures and especially also under cold conditions and at the same time enable high-quality coatings having an even, shiny surface.

Abstract: The invention relates to curable epoxy resin systems comprising polyethylene tetraamine and a tin catalyst as hardening agents, and optionally comprising 1,4-diaza[2.2.2]bicyclo octane. The invention also relates to articles made therefrom, including composites such as carbon fiber reinforced composites. The curable epoxy resins have rapid demold times and/or high glass temperature.

Abstract: A process for making a colored composite pavement structure comprising silylated glass aggregate particles and a polymeric binder composition is disclosed. Systems and methods are also disclosed for providing a colored composite material that cures into a pavement structure. In one embodiment, a colorant concentrate is provided by combining an inorganic colorant with a portion of a first component of a polymeric binder composition. The colorant concentrate can then be combined with the first and second components of the polymeric binder composition to provide a colored polymeric binder composition. The colored polymeric binder composition may then be applied to silylated glass aggregate particles to provide a colored composite material that cures into a pavement structure.

Abstract: Liquid epoxy curing agents that have improved latency over conventional liquid curing agents while retaining the physical properties of the cured material are disclosed. These liquid curing agents can be used for curing epoxy resins, or in combination with dicyandiamide (DICY) based curing agents in order to accelerate DICY curing.

Abstract: A curable divinylarene dioxide resin composition including (a) at least one divinylarene dioxide, and (b) at least one diphenol curing agent; a process for making the curable divinylarene dioxide resin composition; and a cured divinylarene dioxide resin composition made therefrom. The cured product made from the above curable divinylarene dioxide resin composition offers improved properties such as lower viscosity and a high heat resistance compared to known cured products prepared from known epoxy resins.

Abstract: Provided is a modified diene based polymer in which a diene based polymer is graft modified with a polyether having a mercapto group attached via diurethane bonding. Formation of diurethane bonding is performed by allowing sequential reactions of two species of hydroxyl group-containing compounds with an diisocyanate compound. By adding the modified diene based polymer to a silica-containing rubber composition for automobile pneumatic tires, the dispersibility of silica compounded in the rubber composition can be improved, and a property inherent in silica which simultaneously allows a reduction of rolling resistance and a stability on wet road surfaces can be sufficiently effected.

Abstract: An object of the present invention is to provide a coated article having excellent finish and corrosion resistance unaffected by a chemical conversion coating solution even if water washing after a pretreatment step is omitted and a pretreatment solution is carried as a contaminant into an electrodeposition coating composition. The present invention provides a method for forming a multilayer coating film comprising a chemical conversion coating film (F1) and an electrodeposition coating film (F2); the method comprising the following steps. Step 1: immersing a metal substrate in a coating film forming agent (1) as a chemical conversion coating solution to form a chemical conversion coating film (F1); and Step 2: without water washing, subjecting the metal substrate to electrodeposition coating using a coating film forming agent (2) as a cationic electrodeposition coating composition (I) to form an electrodeposition coating film (F2).

Abstract: A curable epoxy resin composite composition including a reinforcing material and an epoxy resin composition, and a process for preparing a composite from such composition; wherein a combination of at least one alkanolamine and at least one styrenated phenol are present in the epoxy resin composition in a sufficient amount to increase the rate of reaction of the at least one epoxy resin and the at least one alkanolamine curing agent while maintaining the thermal and mechanical properties of the composite upon curing of the epoxy resin composition.

Abstract: The present invention relates to an amine curable epoxy resin composition comprising: (A) epoxy resin component comprising: 8-31 wt % of diglycidyl ether of bisphenol A, 3-14 wt % of diglycidyl ether of bisphenol F, 1-5 wt % of monoglycidylether, 0.6-5 wt % of alkylsulphonic phenyl ester, 0.16-1 wt % of wetting and dispersing agent, 0.

Abstract: The present invention pertains to the field of thermosetting or thermoset polymers mainly used as materials, coatings or adhesives. The invention more specifically relates to the use of specific molecules having associative groups including a nitrogen heterocycle as a hardener or co-hardener of thermosetting polymers.

Abstract: A fiber sizing agent is described, which is capable of imparting sufficient sizing properties and fiber spreading properties to reinforced fiber bundles for producing fiber-reinforced composite materials. A fiber sizing agent composition (E) includes a sizing agent (A) having a viscosity of 50 to 3,000 Pa·s at 35° C., and has a thixotropic index of 3 to 15. The sizing agent (A) is preferably an epoxy resin, a polyester resin, a polyurethane resin, a polyether resin or a vinyl ester resin.

Abstract: Glycidylated mono(alkyl aryl)phenols (styrenated phenols) or mixtures thereof are suitable for use as reactive diluents and co-reactants in the production of epoxy resins and have the structure of the general formula I shown hereinbelow wherein R1 and R2 independently of one another denote —H, C1-3-alkyl, C1-3-oxalkyl and glycidyl, but R1 and R2 are not simultaneously glycidyl, R3 is an optionally substituted styryl of the formula R4 is a hydrogen residue or methyl, and R5 and R6 are in each case a hydrogen residue, C1-3-alkyl, C1-2-oxalkyl.

Abstract: An epoxy resin composition for RTM molding of a fiber-reinforced composite material includes [A] to [D] below, wherein [A]/[B], which is a blend mass ratio of [A] to [B], is in the range of 55/45 to 95/5: [A] a multifunctional epoxy resin that is liquid at normal temperature or has a softening point of 65° C. or lower, the multifunctional epoxy resin being at least one selected from phenol novolac epoxy resin, cresol novolac epoxy resin, and triphenylmethane epoxy resin; [B] an alicyclic epoxy resin; [C] an acid anhydride curing agent; and [D] a curing accelerator.

Abstract: A carbon/epoxy resin composition and a method of producing a carbon-epoxy dielectric using the same. The carbon/epoxy resin composition includes about 45 volume percent (volume %) to about 50 volume % of an epoxy composition, the epoxy composition including a bisphenol-based epoxy compound and an alicyclic epoxy compound, based on a total volume of the carbon/epoxy resin composition, about 2.0 volume % to about 3.1 volume % of carbon black, based on a total volume of the carbon/epoxy resin composition, about 80 parts by volume to about 104 parts by volume of an acid anhydride-based curing agent, based on 100 parts by volume of the epoxy composition, and about 1 part by volume to about 3 parts by volume of a tertiary alkylamine-based curing catalyst, based on 100 parts by volume of the epoxy composition.

Abstract: A coating composition is provided for use in laminate substrates useful in packaging of liquids and solids where the coating provides and increased resistance to the permeability of gases such as oxygen and carbon dioxide. In one embodiment the coating composition is a dispersion or a solution that comprises at least one hydroxyl functional polyetheramine, phosphoric acid and a defoamer. The backbone of the polyetheramine has diglycidyl ether linkages that comprise about 5 to about 70 mole percent resorcinol diglycidyl ether. The coating composition can be applied to substrates by coating applications such as spraying, rolling reverse and direct, rolling direct and reverse gravure, kiss coat, flow coating, brushing, dipping and curtain-wall coating, for example.

Abstract: A resin composition comprising an epoxy compound denoted by the formula (1): wherein Ar1, Ar2 and Ar3 are the same or different and each denotes any one of divalent groups denoted by the following formulas: wherein R denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and an epoxy compound denoted by the formula (2): wherein R5 denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and Q2 denotes a single bond or a straight-chain alkylene group having 1 to 8 carbon atoms.

Abstract: A resin composition comprising an epoxy compound denoted by the formula (1): wherein R1, R2, R3, R4 and R5 denote a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, m and n denote an integer of 0 to 4, Ar denotes any one of divalent groups denoted by the following formulas: wherein R denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and an epoxy compound denoted by the formula (2): wherein Q denotes a straight-chain alkylene group having 1 to 8 carbon atoms, methylene groups composing said straight-chain alkylene group are optionally substituted with an alkyl group having 1 to 8 carbon atoms and —O— or —N(R6)— is optionally inserted between the methylene groups, wherein R6 denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

Abstract: Embodiments relate to viscosifiers that are terminated polymers that have functional terminal groups. The polymers being pre-extended by polyepoxides and being reacted to give polymers that are terminated by other functional groups. The viscosifiers have a low content in educts or educt descendants that deteriorate the properties of compositions and considerably reduce or even exclude the formation of high-molecular addition products so that the products obtained have low viscosity and good storage stability.

Abstract: The invention relates to polymeric transition metal catalysts, to processes for preparing them, to intermediates and also to the use of the transition metal catalysts as catalysts in organic reactions, in particular in olefin metathesis reactions.

Abstract: Aqueous radiation curable binders comprising non-ionically stabilized epoxy resins ABC. Resins ABC are an adduct mixture of: adducts formed by the reaction of polyethylene glycol-modified epoxy resins A with olefinically unsaturated acids C, and adducts formed by the reaction of epoxy resins B, that are free from polyethylene glycol derived groups, with olefinically unsaturated acids C. A process for preparing aqueous radiation curable binders comprising non-ionically stabilized epoxy resins ABC, and a process of coating a substrate with aqueous radiation curable binders comprising non-ionically stabilized epoxy resins ABC.

Abstract: A method for producing a branched-polyether resin composition of the present invention includes a first step of obtaining a reaction mixture including: (1-A) a branched-polyether resin (X) containing a hydroxyl group, an acryloyl group, and an epoxy group and (1-B) at least one resin component selected from the group consisting of (1-B-1) a diacrylate (A2) of an aromatic difunctional epoxy resin, (1-B-2) a monoacrylate (A1) of an aromatic difunctional epoxy resin, and (1-B-3) an aromatic difunctional epoxy resin (B) other than (A1) and (A2); and a second step of mixing the reaction mixture and an unsaturated monocarboxylic acid, and reacting the epoxy group in the reaction mixture and a carboxyl group in the unsaturated monocarboxylic acid.

Abstract: Radiation curable compositions comprising at least one radiation curable oligomer obtained from the reaction of one or more carboxyl functional polyester (a) having a glass transition temperature TG and/or melting temperature Tm of less than 30° C., with (b1) one or more (meth)acrylated mono-epoxide, and/or (b2) one or more polyepoxide and one or more ?, ? unsaturated carboxylic acid.

Abstract: A multi-layer composite has at least one elastomer layer and at least one barrier layer. In various embodiments, the composite contains at least two elastomer layers alternating with at least two barrier layers. In other embodiments, the composite comprises at least ten alternating barrier and elastomer layers. The barrier layer is made of an amorphous polymer, and is provided in the form of a film. Preferably, the amorphous polymer film has a gas transmittance rate (GTR) of less than 40 cc·mil/m2·day·atm, preferably less than 20 cc·mil/m2·day·atm, measured as nitrogen transmittance at 0% relative humidity at 23° C.

Abstract: The invention includes compounds represented by Formula (1): wherein R1 is an alkyl having 1 to 20 carbon atoms; A1 and A2 are a 1,4-cyclohexylene or 1,4-phenylene; X is a single bond, —C?C—, —COO—, —OCO—, —CH?CH—COO— or —OCO—CH?CH—; P is an alkylene having 1 to 20 carbon atoms; and p and q are 0, 1 or 2.

Abstract: A copolymer composition comprises an arylate polyester unit, an aromatic carbonate unit, and a soft-block moiety, wherein individual occurrences of the soft block moiety are linked by a spacer unit comprising one or more of the arylate polyester units, one or more of the aromatic carbonate units, or a combination comprising each of these. In one embodiment, a soft block moiety comprises a polysiloxane unit. A film of the composition has a percent transmittance of greater than or equal to 60% as determined according to ASTM D1003-00. A method of forming a copolymer composition is disclosed, comprising substantially forming the bis-haloformates of a dihydroxy compound comprising an arylate polyester unit, and a dihydroxy compound comprising a soft-block moiety, and reacting the bis haloformates with a dihydroxy aromatic compound.

Abstract: A curable underfill encapsulant composition which is especially useful in the no-flow underfill encapsulation process. The composition contains an epoxy resin, a fluxing agent, a linear polyanhydride, a core shell polymer and a catalyst. In an alternative embodiment, the composition also contains a linear anhydride. Various additives, such as surfactants and coupling agents may also be added to the composition.

Abstract: A curable underfill encapsulant composition that is applied directly onto semiconductor wafers before the wafers are diced into individual chips. The composition comprises a thermally curable epoxy resin, a solvent, an imidazole-anhydride curing agent, fluxing agents, and optionally, wetting agents. Various other additives, such as defoaming agents, adhesion promoters, flow additives and rheology modifiers may also be added as desired. The underfill encapsulant is B-stageable to provide a coating on the wafer that is smooth, non-tacky and will allow the wafer to be cleanly diced into individual chips. A method for producing an electronic package containing the B-stageable material may also utilize an unfilled liquid curable fluxing material on the substrate to which the chip is to be attached.

Abstract: The object of the present invention is to provide an epoxy resin and epoxy resin composition having a low viscosity which can afford a cured product having an excellent heat resistance. The present invention is characterized by using an epoxy resin which is obtained by reacting 5-methylresorcin with epihalohydrin in the presence of alkali metal hydroxide.

Abstract: A coating composition comprises a polycondensate obtained by reacting a prehydrolysate based on at least on epoxide-containing hydrolysable silane; at least one amine component selected from a prehydrolysate based on at least one amino-containing hydrolysable silane and an amine compound containing at least two amino groups; and an amino group protective reagent. The coating composition is particulary suitable for coating glass, glass ceramic, ceramic, and plastic, and permits an increase in strength and protection against damage.

Abstract: The present invention provides a cationic coating composition capable of forming a coating film which is excellent in an electrodepositablly coating property and an adhesive property toward a rust preventive steel plate, a corrosion resistance and a low temperature curability. The cationic coating composition described above comprises as a vehicle component, a xylene-formaldehyde resin-modified, amino group-containing epoxy resin obtained by reacting an epoxy resin (A) having an epoxy equivalent of 180 to 2500 with a xylene-formaldehyde resin (B) and an amino group-containing compound (C).

Abstract: Binders for aqueous corrosion protection systems, comprising products A′ABC of reaction of epoxy resins, fatty acids, and amines, having a number average molar mass Mn of at least 5000 g/mol, obtained by reacting epoxide compounds A′ containing at least two epoxide groups per molecule and reaction products ABC of epoxide compounds A, fatty acids B, and amines C, wherein, where appropriate, the epoxide compounds A′ and/or the epoxide compounds A have been modified prior to further reaction, in whole or in part, by reaction with compounds D containing at least one acid group or hydroxyl group reactive toward epoxide groups, and wherein, where appropriate, the amines C have been modified prior to further reaction, in whole or in part, by reaction with aliphatic or aromatic monoepoxide compounds A″ or mixtures thereof.

Abstract: Gel formation is prevented in the reaction between a sulfonyl-chloride-containing resin and a polyamine by first forming an adduct between the resin with an aminophenol. The prevention of gel formation enables sulfonyl-chloride containing resin to be used in admixture with acrylates and epoxy resin to form a polyamine-curable adhesive composition having excellent adhesive properties and chemical resistance.

Abstract: Water-dilutable, cationically stabilized epoxy resins ZYX are obtained by reacting, in the first stage, aromatic or aliphatic epoxide compounds Z with aliphatic amines Y to form epoxy-amine adducts ZY which are neutralized and then in aqueous dispersion are reacted in a second stage with a further epoxy resin X. The resins ZYX may be formulated without additional curatives to give aqueous coating materials which exhibit a good corrosion protection effect.

Abstract: Curable compositions, reaction products of which are reworkable through thermal decomposition, are provided. Specific compounds useful in such curable compositions, as well as curable compositions and thermosets incorporating such compounds, are provided in the present invention. The compounds include a cyclic hydrocarbon moiety including an oxirane or thiirane group and an aromatic ether moiety including an oxirane or thiirane group. The cyclic hydrocarbon moiety and the aromatic ether moiety are joined to each other through an oxycarbonyl-containing linkage or a thiocarbonyl-containing linkage, preferably a secondary or tertiary linkage. Compositions incorporating such compounds are capable of curing by exposure to a specific temperature, and are decomposable at a temperature in excess of the curing temperature, thus providing a composition which is reworkable.

Abstract: The invention provides polyepoxide-based adhesives containing cycloaliphatic-containing polyepoxide resin, aromatic polyepoxide resin, and 9,9-bis(3-methyl-4-aminophenyl)fluorene. The adhesives provide improved peel and shear strength.

Abstract: An epoxy resin composition comprising, as main components, (a) 100 parts by weight of a polyfunctional epoxy resin which stays liquid at an ordinary temperature and has two or more glycidyl groups in the molecule thereof, (b) 3 to 80 parts by weight of a curing agent and (c) 1 to 100 parts by weight of a modified epoxy resin, is suitable as an underfill sealing agent, is capable of heat-curing in a short time with a good productivity, is capable of surely connecting a semiconductor device such as a CSP and a BGA on a wiring board without giving an adverse effect on each part disposed on the wiring board by heat-curing at a relatively low temperature, has excellent heat shock property (temperature cycling property) and impact resistance, is free from bleeding of contaminants from its cured product, and is capable of easily detaching the CSP or BGA from the wiring board in the case where a defect is found, making it possible to reuse a normal wiring board or semiconductor device.

Abstract: A curable underfill composition comprising an epoxy containing a curing agent component and a latent accelerator component. The accelerator component comprises a material which produces a resin with an exotherm below 300 J/g. Further, the combination may be utilized in an unfilled state which allows the epoxy to remain very viscous and thus increases the speed of the underfill process in comparison to filled epoxy compositions and epoxy compositions containing different accelerator components.

Abstract: A one part, several-months-useful-shelf-life epoxy material suitable for potting and sealing electronic components, and which is compatible with the high, approximately 255° C. to 275° C. temperatures required for soldering modem lead-free solders comprises an intimate mixture of the following components: approximately 2 to 13 per cent by weight of diglycidyl ether bisphenol A resin; approximately 40 to 70% phenol formaldehyde resin and the following further components [(2-methylphenoxy)methyl]-oxirane or o-cresol glycidyl ether) 0.5-8% by weight; polypropyleneglycol-glycidyl ether resin (plasticizer) 2-10% by weight; cycloaliphatic polyamine (catalyst) 4-15% by weight; kaolin clay (filler) 2-20% by weight; magnesium alumino silicate (filler) 2-15% by weight; Sb2O3 (filler) 4-5% by weight, and hydrated Al2O3 (filler) 0-15% by weight.

Abstract: A new brominated epoxy resin has been developed, which consists of following components: A. multifunctional phenol-benzaldehyde epoxy resin (formula 1) 10˜70 weight %; B. difunctional epoxy resin 0˜55 weight %; C. bromine-containing difunctional epoxy resin 0˜20 weight %; D. tetrabromobisphenol-A epoxy resin 15˜40 weight %; The synthesis is that (D) tetra bromo bisphenol-A reacts with at least one of (A), (B)and (C), then adding the rest of (A),(B) and (C) and mixing them uniformly, the new brominated epoxy resin produced, which can be applied to glass fiber laminate, and showing proper reactivity and a broad working window. The laminate possesses high Tg and good heat resistance, and applying to electron material with high performance.

Abstract: The present invention provides a partial condensate of glycidyl ether group-containing alkoxysilane which is obtainable by dealcoholization reaction between glycidol and a partial condensate of alkoxysilane, compositions comprising the same and preparation methods thereof. Further, the present invention provides an alkoxy-containing silane-modified polyimide resin, alkoxy-containing silane-modified polyamide-imide resin and alkoxy-containing silane-modified phenol resin which are modified with the partial condensate of glycidyl ether group-containing alkoxysilane, and preparation methods thereof.

Abstract: The present invention discloses a continuous process and the associated system for upstaging liquid epoxy resins to produce resins with higher molecular weight. The process comprises passing continuously (i) a liquid epoxy resin having a first molecular weight, (ii) a catalyst and (iii) a compound having at least one active hydrogen or reactive functional group capable of reacting with the liquid epoxy resin in the presence of the catalyst, flow through one or more reaction chambers and under conditions effective to produce a stream comprising an upstaged epoxy resin product having a second molecular weight. The second molecular weight is higher than the first molecular weight.

Abstract: A curable epoxy resin formulation comprising a) 40 to 100% by weight of an epoxy group-terminated polyester of a dimerised or trimerised fatty acid and a polyhydric alcohol, and 0 to 60% by weight of a diepoxide which is not an epoxy group-terminated polyester, b) a hardener for epoxy resins consisting of 50 to 99% by weight of a polyoxyalkylene di- or triamine and 1 to 50% by weight of a hardener which is not a polyoxyalkyleneamine, and comprising as further optional components c) a curing accelerator, and d) customary modifiers for epoxy casting resins, with the proviso that the sum of the constituents in component a) as well as in component b) is in each case 100% by weight, is suitable for use as casting resin formulation for encapsulating electrical or electronic components.

Abstract: The subject invention pertains to an aqueous primer for use on metal surfaces to which a composite or a metal adherend is bonded. The primer composition includes an aqueous dispersion of: (a) at least one thermosetting resin curable at an elevated temperature; (b) at least one organosilane, each said organosilane containing at least ore hydrolyzable group; and (c) a curing agent. The aqueous primer composition contains substantially no volatile organic solvent, is environmentally superior to solvent-based primers, is storage stable, exhibits excellent solvent resistance and performs without loss of physical properties.

Abstract: A liquid epoxy-based potting composition has a glass transition temperature equal to or greater than 200° C. and comprises a cyclo-aliphatic epoxy, present in an amount of 50 to 80 parts by weight; a multi-functional aromatic epoxy (having more than two epoxy groups per molecule), present in an amount of 20 to 50 parts by weight; a liquid anhydride, present in an amount of 80 to 150 parts by weight; a basic latent accelerator, present in an amount of 1 to 5 parts by weight; and a filler, present in an amount of 100 to 500 parts by weight.

Abstract: A curable composition comprises a compound having at least one epoxy group and at least one styrenic or cinnamyl group per molecule.

Abstract: This invention relates to novel polyamines which are the reaction product of A) at least one nonaromatic diamine containing from 2 to 40 carbon atoms, wherein the amine groups are primary amine groups; and B) at least one epihalohydrin of the formula  where R is hydrogen or methyl and X is chlorine or bromine; and the coatings resulting from the reaction between the above reaction product and nonaromatic epoxy resins.

Abstract: Metal cyanide catalysts are complexed with organic sulfone or sulfoxide compounds. The catalysts are active alkylene oxide polymerization catalysts that tend to have short induction periods and moderate exotherms.

Abstract: Coating composition including a film-forming component, further including (a) a product formed by reacting a mixture including carboxy functional polymer, hydroxy functional polymer, or a mixture thereof, or ethylenically unsaturated monomer, with epoxy resin, and (b) a polyvinyl alcoholic-containing phenolic resol resin. Also provided is a method of coating a metal substrate with said coating composition. Further provided is a composite material comprising a metal substrate having at least one surface covered with a cured film of the coating composition.

Abstract: Epoxy resin compositions comprising polyepoxides having at least two 1,2-epoxide groups, which can be obtained by reaction of diepoxides or polyepoxides or mixtures thereof with monoepoxides, and one or more amines sterically hindered amines, such as disecondary polyoxyalkylenediamines, and/or diprimary diamines, if desired with the addition of further 1,2-epoxide compounds and also hardeners, and use thereof as a coating for crack bridging, as an adhesive and in powder surface coatings.

Abstract: A lactone chain-extended polyester polyol of the present invention comprises the reaction product of a lactone and a previously chain-extended phenolic-based hydroxyl compound. The previously chain-extended phenolic-based hydroxyl compound may comprise the reaction product of (i) a lactone or an alkoxylating agent selected from the group consisting of alkylene oxides and alkylene carbonates, and (ii) a phenolic aralkylation polymer comprising the reaction product of a phenolic monomer having at least two free reactive positions; a styrene derivative; and a coupling agent. The previously chain-extended phenolic-based hydroxyl compound also may be chain-extended by reacting with a lactam to produce a lactam chain-extended polyester polyamide. The polyols and polyamides of the present invention provide unique combinations of hard and soft functionalities, which translates into materials exhibiting a unique combination of toughness and hardness.