Abstract: A thermosetting liquid moulding composition comprising:(a) a polyepoxide containing at least two epoxide groups per molecule;(b) a tricarboxylic acid definable by the general formula: ##STR1## where: R.sup.1, R.sup.2 and R.sup.3 have the meaning given in the description; and(c) a diacarboxylic acid anhydride.This composition can be transformed by liquid moulding into manufactured articles particularly useful in the electrical sector.

Abstract: Epoxide compounds and phenolic compounds are reacted in the presence of phosphonium compounds represented by the formula .crclbar.Z'R.sup.1 R.sup.2 R.sup.3 P.sym.-Z-P.sym.R.sup.1 R.sup.2 R.sup.3 Z'.crclbar. wherein each R.sup.1, R.sup.2 and R.sup.3 is independently an aromatic group or an inertly substituted aromatic group; Z is --(C(R.sup.4).sub.2).sub.a --; each R.sup.4 is independently hydrogen or a hydrocarbyl group containing from 1 to about 20 carbon atoms; Z' is any suitable anion and a has a value of at least 4.

Abstract: A coating material for a tendon for prestressed concrete includes a curing composition, the curing time of which is so controlled that the composition is held in an uncured fluid state for a predetermined time after the concrete hardens. After the predetermined time passes, the composition cures. By coating a tendon for prestressed concrete with the coating material having such properties, an antirust effect of the tendon, an improved adhering force of the tendon to the concrete and a decreased cost of manufacturing prestressed concrete can be obtained.

Abstract: Curable mixtures comprising(a) at least one epoxy resin containing on average more than one, 1,2-epoxy group per molecule,(b) at least one cyclic carboxylic anhydride,(c) an adduct of a zinc salt of a C.sub.6 -C.sub.18 carboxylic acid with a tertiary amine, and(d) optionally a filler and/or further conventional modifiers have a long pot life without impairment of the brief curing time at elevated temperatures.

Abstract: A method for the preparation of insoluble, infusible epoxy resins containing reversible crosslinks comprising the steps of:(a) forming a reaction mixture of(i) an epoxy compound having two or more epoxy groups, and(ii) a crosslinking agent containing two or more epoxy-reactive groups and further containing a disulfide bond, said crosslinking agent being selected from compounds having the formulaQ--X--S--S--X--Qwhere Q is an epoxy-reactive functional group selected from ##STR1## and X is a divalent aromatic or aliphatic hydrocarbon radical of one to ten carbon atoms, and(b) curing said reaction mixture under conditions conductive to the formation of a crosslinked resin.The epoxy resin can be solubilized by cleavage of the disulfide bond by reduction in the presence of a solvent. The resultant thiol groups can be reoxidized to form the disulfide linkages or can be modified by other reactions.

Abstract: The invention relates to polymers of formula (I) ##STR1## in which R.sup.1 and R.sup.2 represent optionally substituted alkylene, cycloalkylene or phenylene radicals, A represents hydrogen or carboxyl groups, B represents hydrogen or groups derived from carboxylic acids or isocyanates. The invention also relates to aqueous epoxy resin dispersions containing one or more polymers of general formula (I) in addition to bases, acid, one or more emulsifiers and, optionally, other active substances and auxiliaries typically used in epoxy resin dispersions and also water.The invention also relates to a process for the production of such aqueous epoxy resin dispersions and to the use of such resins in processes for the autophoretic coating of metallic surfaces.

Abstract: A low viscosity product is obtained when an adduct is prepared by reacting (A) at least one polyglycidyl ether of a compound containing an average of more than one phenolic hydroxy group per molecule and (B) at least one aliphatic monocarboxylic acid containing 7 to 15 carbon atoms per molecule; wherein components (A) and (B) are present in amounts which provide a ratio of carboxylic acid groups per epoxide group of from about 0.01:1 to about 0.2:1.

Abstract: The invention is an epoxy resin thermoset adhesive composition. The composition comprises the cured reaction product of:(A) an epoxy base resin, and(B) a curing amount of an admixture comprising:1. an amidoamine of the formula: ##STR1## wherein: P is an iso or para phenylene moiety, and R is the polyoxypropylene moiety of the formula:H.sub.2 NCH(CH.sub.3)CH.sub.2 --[OCH.sub.2 CH(CH.sub.3)].sub.x NH--wherein: x ranges from 2 to 40, and2. an aliphatic polyetheramine, aromatic amine or mixture thereof.The compositions cured at elevated temperature cross-link to form adhesives demonstrating high peel strength and high shear strength.

Abstract: Non-fluorinated epoxy resins of a known type are cross-linked by means of polyfunctional fluoroalkanes containing groups which are reactive with the epoxy groups and/or with the hydroxy groups present in the starting resin. The cross-linked products so obtained, having a fluorine content not higher than 15% by weight, and preferably ranging from 1% to 5%, exhibit a complex of properties which are typical of the corresponding fluorinated resins having a much higher fluorine content; in particular, oil- and water-repellency, resistance to hydrolysis and to solvents, and minimum absorption of water.

Abstract: Disclosed as a polyether compound having ether groups and vinyl double bonds represented by formula (I) ##STR1## and an epoxy resin represented by formula (II) ##STR2## wherein R.sup.1 represents a residue group of an organic compound having l active hydrogen atoms, n1 through nl each represents 0 or an integer of from 1 to 100, the sum of integers represented by n1 through nl is from 1 to 100, and l represents an integer of from 1 to 100, and A represents from 1 to 100, and A represents ##STR3## or a mixture of ##STR4## wherein R.sup.2 represents a residue group of mono epoxy compound, and B represents ##STR5## or a mixture of ##STR6## wherein X represents a ##STR7## group, wherein R.sup.3 represents a hydrogen atom, an alkyl group, an alkyl carbonyl group, or an arylcarbonyl group, provided that the epoxy resin represented by formula (II) contains at least one ##STR8## group: In a further aspect, the invention relates to processes for production thereof.

Abstract: A process is disclosed for preparing an advanced epoxy resin by reacting a relatively low molecular weight polyepoxide with a phenol, thiophenol, carboxylic acid or carboxylic acid anhydride in the presence of a catalytic amount of an alkyl substituted phosphonium salt such as tributyl phosphonium bromide. The process can be carried out under reaction conditions, such as the presence of water, which are deleterious to certain epoxy advancement catalysts.

Abstract: An anodic electrodeposition composition containing a water-soluble or water-dispersible modified epoxy resin derived from an epoxy resin having two epoxide groups and at least one alcoholic hydroxy group at the terminals and the middle of the resin backbone, respectively. The modified epoxy resin has at least one polymeric side chain block bound to said alcoholic hydroxy group and at least one acid group derived from said terminal epoxide group.

Abstract: Non-fluorinated epoxy resins of known type are crosslinked by means of polyfunctional perfluoropolyethers containing groups which are reactive with the epoxy groups and/or with the hydroxy groups present in the starting resin. The so-obtained crosslinked products, with a fluorine content not higher than 20% by weight, preferably comprised within the range of from 5% to 15%, are endowed with a set of properties typical of the corresponding fluorinated resins with a much higher fluorine content, in particular, water- and oil-repellence, resistance to hydrolysis and to solvents, minimum water absorption.

Abstract: Certain cobalt(II) complexes such as secondary amine adducts of cobalt(II) acetylacetonate have been found useful as latent catalysts for anhydride-epoxy blends.

Abstract: The invention is an epoxy resin thermoset adhesive composition. The composition comprises the cured reaction product of:(A) an epoxy base resin, and(B) a curing amount of an admixture comprising:1. an oxamidoamine of the formula: ##STR1## wherein: R is the polyoxypropylene moiety of the formula:H.sub.2 NCH(CH.sub.3)CH.sub.2 --[OCH.sub.2 CH(CH.sub.3)].sub.x NH--wherein: x ranges from 2 to 40, and2. an aliphatic polyetheramine, aliphatic polyamine, aromatic amine or mixture thereof.The adhesives are cured at elevated temperature. They are noted for high peel strength and good shear strength.

Abstract: Epoxy resins of increased functionality are prepared by branching the epoxy resin in the presence of a lithium or cesium compound as a branching catalyst until the desired functionality is obtained and thereafter terminating the branching reaction. Since the lithium and cesium compounds are not deactivated by the aliphatic chloride typically found in an epoxy resin, the branching reaction can effectively be conducted even at low concentrations of the lithium or cesium compound. Termination of the branching reaction is conducted by cooling the branching reaction mixture or by the addition of a deactivating agent which stops or effectively reduces the rate of the branching reaction. Due to the low conecntration at which the branching catlayst can be employed, the resulting branched epoxy resins can be prepared without visible turbidity.

Abstract: A composition comprising an epoxy resin and an aromatic azopolyamine curing agent is described. The use of azopolyamine curing agents in reactive monomer-diluted systems results in a high-modulus cured epoxy system.

Abstract: The invention discloses crosslinking components for hydroxy and/or primary and/or secondary amine groups containing cationic resins which can be used as binders for stoving paints, particularly for cathodically depositable electrodeposition paints. The crosslinking components are obtained through partial transesterification of transamidation of oligomeric KNOEVENAGEL-reaction products of C-H-active esters and carbonyl compounds with polyols or amines. The products can also be obtained through partial transesterification or transamidation of the C-H-active esters and subsequent KNOEVENAGEL-reaction.

Abstract: There is provided a novel polymaleimide compound represent by the formula (a) ##STR1## The present polymaleimide compound has a curability comparable to that of an epoxy resin. In addition, it is noted that a cured product prepared from the present polymaleimide compound is excellent in heat resistance and adhesion property and has a low linear expansion coefficient as compared with an epoxy resin. The above-mentioned excellent characteristics of the present polymaleimide compound are never observed with respect to conventional maleimide resins. There is also provided specific compositions containing the present polymaleimide compound for exerting the excellent effects of the present polymaleimide compound most effectively.

Abstract: Disclosed herein are high solids thermosetting coating compositions comprising hydroxy-functional polyepoxides and anhydrides as effective curing agents thereof. Films of these coating compositions are of remarkable appearance and are attended by remarkably low volatile organic content (VOC).

Abstract: A coated article is made by: (1) admixing an epoxy resin, with a dual curing agent admixture of (a) an irradiated mixture of carboxylic acid anhydride and carbon containing cyclic compound and (b) a boron trihalide complex selected from at least one of boron trihalide:amine and boron trihalide:ether, (2) applying the mixed resin and concentrated dual curing agent to the surface of an article, and (3) curing the applied resin and curing agent.

Abstract: Epoxy resins have been found to be fortified (increased in strength and modulus yet not made brittle) by compounding:(a) a resin-forming polyepoxide(b) an amine curing agent for (a) and(c) a fortifier for (a)+(b) comprising the reaction product of(i) an aromatic polyhydroxy compound and(ii) a diepoxide with one epoxy group less reactive than the other:and heat curing the mixture. Strengths as high as 140 MPa and moduli as high as 4500 MPa have been attained with a ductile mode of failure.

Abstract: According to the invention, a relatively low molecular weight epoxy resin is reacted with a hydroxyl group-containing compound in the presence of a bis(trihydrocarbyl phosphine)iminium salt catalyst to produce a high molecular weight fusion reaction product. The process is particularly useful in reacting an epoxy resin having a molecular weight of less than about 500 with bisphenol-A in the presence of a bis(phosphine)iminium halide to produce a fusion reaction product having a molecular weight within the range of about 500 to 7000. The catalyst is relatively water-insensitive, and the reaction can therefore be carried out in the presence of water.

Abstract: A curing agent for an epoxy resin comprises a cyclodextrin clathrate compound of a compound which is reactive with an epoxy group, a curing agent for an epoxy resin comprising a mixture of a cyclodextrin clathrate compound of a compound which is reactive with an epoxy group with a trace amount of amylase, and methods for the preparation of these curing agents. The curing agents are stable at room temperature, and the curing reaction is initiated under remarkably simple conditions.

Abstract: This invention is directed to adducts of a poly(active hydrogen) organic compound and a polyepoxide comprising the reaction product of a poly(active hydrogen) organic compound and a polyepoxide containing two or more epoxy groups per molecule, said poly(active hydrogen) organic compound being employed in an amount at least sufficient to effect substantially complete reaction of the epoxy groups of the polyepoxide. The adducts are useful in the formulation of high solids coating compositions, polyurethane elastomers, inks, sealants, adhesives and the like.

Abstract: A method is disclosed for deactivating a hydrocarbyl phosphonium salt catalyst of an epoxy resin fusion reaction. The method involves contacting the hydrocarbyl phosphonium salt catalyst with a sulfonic acid, such as p-toluenesulfonic acid or methane sulfonic acid. The method is particularly suited for deactivation of moisture-resistant phosphonium salts such as methylene bis(triphenyl phosphonium halide)s.

Abstract: A curable epoxy resin composition, comprising (1) an alicyclic epoxy resin having an average of more than one epoxy group per molecule, (2) a polybasic acid hydrazide, and (3) a latent curing agent for said epoxy resin which comprises an addition product obtained by reacting (a) a polyfunctional epoxy compound with (b) a compound having at least one functional group in the molecule selected from the group consisting of OH, SH, COOH and CONHNH.sub.2 together with a tertiary amino group, or by reacting said components (a) and (b) with (c) an organic compound which has more than two active hydrogen atoms in the molecule, said reactions occurring under conditions in which the ratio of (a) to (b) or (a) to (b) and (c) ranges from 0.8 to 2.5 equivalents of (a) per equivalent of the total active hydrogen atoms in component (b) and in components (b) and (c), the molar ratio of (c) to (b) being 0.2:1 to 1:1, and said addition product having a softening point of 60.degree. to 180.degree. C.

Abstract: This invention relates to heat-hardenable epoxide resin mixtures of at least one 1,2-polyepoxide having more than one 1,2-epoxide group per molecule, at least one cyclic carboxylic acid anhydride and at least one ammonium phosphonate or ammonium phosphate as a hardening catalyst, as well as further optional auxiliaries.

Abstract: A mixture of an adhesive composition comprising (A) an epoxy resin and an oxime carbamate and (B) an amine hardener containing primary, secondary or tertiary amino or amido-amine groups and its process for curing said adhesive are described.

Abstract: Compositions for the preparation of thermosetting or thermoplastic polymers, which compositions comprise a mixture of at least one polyepoxide and at least one polyamide oligomer, wherein the oligomer is a primary monoamine, an alpha,omega-primary or -secondary diamine, an alpha,omega-diacid or an alpha-primary amine,omega-acid, together with processes for preparing polymers and the uses of such materials for molding and for adhesives.

Abstract: Aromatic amines and their alkyl, amide, imide or amide-imide substituted derivatives in the presence of catalytic quantities of phenols, cresols, xylenols, bisphenols, and their like cause epoxide resins to thermoset at ambient temperatures. The resulting crosslinked polymers are useful for two component solution systems which provide corrosion and temperature resistant clear coatings or paints, and can also be used as solventless, liquid, two component systems for casting clear, pigmented or filled parts.

Abstract: This invention relates to a stable acid anhydride paste mixture useful as a crosslinking agent for epoxy resins and a dual catalyst system therefor. In particular, the anhydride mixture comprises high melting point acid anhydride, a liquid acid anhydride, and a low melting point acid anhydride. The dual catalyst system comprises tertiary amine catalysts with boron trihalide amine complex catalysts.

Abstract: This application discloses a synthetic resin based on alcohol-modified polyepoxides. The synthetic resin can be prepared by reacting a diepoxide, or a mixture of diepoxides, having an epoxide equivalent weight of less than about 500, with compounds with a hydroxyl group, which is reactive towards epoxide groups, in a molar ratio from about 2:1 to about 7:6 at temperatures from about 100.degree. C. to about 180.degree. C. in an organic solvent free of hydroxyl groups. The synthetic resin has terminal epoxide groups and a mean molecular weight from about 400 to about 5000.

Abstract: A process for the rapid formation of thermoset polymers by polymerizing a mixture of a polyepoxide with a polycarboxylic acid containing an alkali or alkaline earth metal cationic complex catalyst is disclosed.

Abstract: Disclosed is a 2-substituted-4,6-diamino-s-triazine/isocyanuric acid adduct represented by the following formula: ##STR1## wherein R stands for an alkyl group having 2 to 20 carbon atoms, an unsubstituted or cyano group-substituted aryl group, or a group of the formula R.sup.1 --CH.sub.2 CH.sub.2 -- in which R.sup.1 stands for an alkoxy group having up to 20 carbon atoms, an acyloxy group, an amino group, an N-substituted amino group, a benzotriazolyl group or a 2-alkylimidazolyl-(4)-dithiocarbonyl group, or by the following formula: ##STR2## wherein R.sup.2 stands for an alkylene group which may have an intervening imino or phenylene group.When this adduct is used for curing a polyepoxy resin, a cured product having good heat resistance, insulating property and adhesion and an excellent migration-preventing effect is formed.

Abstract: A polymeric reaction product, a process for its preparation and a coating composition containing the reaction product as a binder are described. The polymeric reaction product is prepared by the vinyl addition polymerization of a vinyl monomer component of which at least 50 percent by weight is an active hydrogen-containing vinyl monomer in the presence of a polymeric diluent. The rate of polymerization is controlled such that the amount of unreacted vinyl monomer, on the average, does not exceed 10 percent by weight of the total weight of the reaction mixture.

Abstract: Heat-curable compositions are described, comprising(a) an epoxide resin and(b) an effective amount of a urea of formulaAr--NHCON(R.sup.3)R.sup.4whereAr represents an aromatic group linked through an aromatic carbon atom to the indicated nitrogen atom and which is substituted by an amido group, andR.sup.3 and R.sup.4 each represent an aliphatic, cycloaliphatic, or araliphatic hydrocarbyl group, optionally substituted by a halogen atom or a hydroxyl group, or R.sup.3 may further represent a hydrogen atom, or R.sup.3 nd R.sup.4, together with the indicated nitrogen atom, may represent a heterocyclic ring of 3 to 5 carbon atoms which may also have one oxygen atom in the ring.Such amidoarylureas may be used alone with the epoxide resin, or in combination with an accelerator for the heat-curing reaction, selected from dicyandiamide, carboxylic acid hydrazides, succinimide, cyanoacetamide, 1-cyano-3-(lower alkyl)guanidines, imidazoles, and carboxylic acid-tertiary amine salts.

Abstract: Michael addition products of monocarboxylic or dicarboxylic acid esters, capable of undergoing Michael addition, with compounds containing double bonds capable of undergoing Michael addition are suitable for use as a curing component for synthetic resins containing groups capable of amide formation and/or ester formation with carboxylic acids. In particular, the Michael addition products of acetoacetic esters or malonic esters with esters, amides or urea derivatives of .alpha., .beta.-unsaturated monocarboxylic or dicarboxylic acids are used. The structure and the functionality of the curing component can be varied in many ways. It can be attached directly to the synthetic resin molecule, so that self-curing synthetic resins are obtained.

Abstract: Thermosettable compositions are prepared which contain (A) from about 0.1 to 100 percent by weight of an esterified aromatic cyanate; (B) from zero to about 99.9 percent by weight of an aromatic polycyanate, an aromatic polycyanamide or mixture thereof and (C) from zero to about 99.9 percent by weight of an epoxy resin.

Abstract: Relatively high molecular weight epoxy resins cured with conventional curing agents are disclosed wherein the relatively high molecular weight epoxy resin is prepared in the presence of the curing agents. The resultant cured epoxy resin has an improvement in Tg or toughness and the mixture prior to reaction and curing is much easier to apply as a coating or in the preparation of castings, laminates and the like as compared to applications of mixtures of relatively high molecular weight epoxy resins and the curing agents.

Abstract: There are described novel imidazolides (N-acylimidazoles) of the formula I ##STR1## wherein R.sub.1 is methyl, ethyl or isopropyl,R.sub.2, R.sub.3 and R.sub.4 independently of one another are each hydrogen, methyl, ethyl or isopropyl, with the proviso that R.sub.2 is hydrogen only when R.sub.1 is isopropyl,R.sub.5, R.sub.6 and R.sub.7 independently of one another are each hydrogen, methyl, ethyl or isopropyl, or phenyl which is unsubstituted or substituted by methyl or ethyl groups, with the proviso that at least one of the symbols R.sub.5, R.sub.6 and R.sub.7 is phenyl which is unsubstituted or substituted according to definition.The imidazolides (I) are suitable as curing agents for polyepoxide compounds.

Abstract: N-cyanoacylamide compounds are prepared by reacting 1 mol of an N-cyanocarboxylic acid amide salt with 1 mol of a halogen compound in a polar, aprotic solvent.The N-cyanoacylamide compounds can be used for hardening epoxide resins, for the preparation of isomelamine or for the preparation of linear polymers which can be crosslinked by heat.

Abstract: A polyether compound having ether groups and vinyl double bonds represented by formula (I) ##STR1## wherein R.sub.1 represents a residue of an organic compound having l active hydrogen atoms, n.sub.1 through n.sub.l each represents 0 or an integer of from 1 to 100, the sum of the integers represented by n.sub.1 through n.sub.l is from 1 to 100, andl represents an integer of from 1 to 100, and A represents ##STR2## and a process for production thereof; an epoxy resin represented by formula (II) ##STR3## wherein R.sub.1 and n.sub.1 through n.sub.l are defined above, and B is an oxycyclohexane unit having a substituent and is represented by formula (III) ##STR4## wherein X represents a ##STR5## --CH.dbd.CH.sub.2, or ##STR6## groups, wherein R.sub.

Abstract: A curable composition consisting ofA. 100 parts by weight of an epoxy resin,B. from 4 to 100 parts by weight of a conventional curing agent for epoxy resins, andC. from 0.1 to 5 parts by weight of an N-acylimidazole which possesses an aromatic acyl component which is substituted at the two positions ortho to the carbonyl groupcan be used to produce moldings, coatings, finishes, adhesives and composite fiber materials.

Abstract: Heat curable epoxy-styrene compositions exhibiting improved processability, low viscosity, long pot life, and fire retardancy which when cured with a special acid anhydride/onium salt epoxy curing blend in combination with a free-radical catalyst, yield cured products exhibiting improved physical properties, such as increased heat deflection temperature, increased flexural strength and increased flexibility.

Abstract: Novel solvent-based thermosetting composition comprising (a) hydroxy functional epoxy ester resin of number average molecular weight (Mn) between about 1,000 and about 5,000, comprising the reaction product of diepoxide with diphenol, dicarboxylic acid and acid component comprising hydroxy functional acid and optionally further comprising fatty acid; and (b) polyfunctional, hydroxy-reactive crosslinking agent, for example, aminoplast crosslinking agent or blocked polyisocyanate crosslinking agent comprising isocyanate groups blocked by reaction with an active hydrogen bearing blocking agent. Coating composition may be formulated as primer sprayable with conventional spraying equipment.

Abstract: Novel tetraglycidyl ethers of the formula ##STR1## wherein X is a group ##STR2## R is hydrogen or methyl, and n is an integer from 2 to 4. The novel tetraglycidyl ethers can be used in curable mixtures, together with a curing agent for epoxide resins, in particular for the protection of surfaces.

Abstract: An addition product obtained by reacting (a) a polyfunctional epoxy compound and (b) a compound having at least one functional group of OH group, SH group, COOH group and CONHNH.sub.2 group together with a tertiary amino group in the molecule, and an addition product obtained (a), (b) and (c) an organic compound having two or more active hydrogen atoms in the molecule (excluding a compound having an epoxy group or tertiary amino group) are good curing agents for epxoy resin. The curing agents are useful in formulating novel storable one-package, heat-curable epoxy resin-based compositions.

Abstract: Aromatic N-glycidylamines are prepared by treatment of an amine having at least one, and preferably two or more aromatic amino hydrogen atoms, with epichlorohydrin in the presence, as catalyst, of a di- or higher-valent metal salt of nitric or perchloric acid, or of a carboxylic or sulphonic acid substituted by fluorine, chlorine or bromine on the carbon atom alpha to the carboxylic or sulphonic acid group, and dehydrochlorinating the product. The presence of the metal salt gives a product having a higher glycidyl content and a lower viscosity than does the same reaction in the absence of such a salt.Suitable aromatic amines include aniline, phenylene diamines, phenylene diamines substituted on the aromatic ring and bis(4-aminophenyl)methane. The metal salt may be of, for example, magnesium, calcium, zinc, manganese, nickel, iron, lanthanum, vanadium, ytterbium or uranium.

Abstract: A solvent-free curable composition has a long shelf life and consists ofA 100 parts by weight of an epoxy resin andB from 10 to 100 parts by weight of .[.,.]. .Iadd.4,4-bis-(para-aminobenzoyl)-piperazine .Iaddend.as a curing agent for the epoxy resin, .[.an aromatic diamine containing ##STR1## groups,.]. with or without C from 0.01 to 5 parts by weight of an accelerator, the curing agent for the epoxy resin being finely dispersed in the latter and preferably having a particle size of less than 10 .mu.m. .[.The preferred epoxy resin curing agent is 4,4'-diaminodiphenyl ketone..]. The curable composition is used in particular for the preparation of fiber-reinforced materials.