WO1993014140A1

WO1993014140A1 - Epoxidation products of 1,3,5-tris(4'-hydroxyphenyl)benzenes____

Info

Publication number: WO1993014140A1
Application number: PCT/US1993/000125
Authority: WO
Inventors: Charles B. Hilton
Original assignee: Hoechst Celanese Corporation
Priority date: 1992-01-08
Filing date: 1993-01-06
Publication date: 1993-07-22

Abstract

Epoxidation product of a 1,3,5-tris(4'-hydroxyphenyl)benzene compound of formula (I) and an epihalohydrin of formula (II) wherein: each R is a C1-12 alkyl, phenyl or C3-6 cycloalkyl; each X is halogen or nitro; each p is 0, 1 or 2; each n is 0, 1 or 2; for each ring n + p = 0 to 4; X1 is Cl, Br, I or F, typically Cl or Br; Y is H or CH¿3?; and, the epoxidation product has an average epoxide functionality of from 2.5 to 6 or at least about 70 % of theoretical. Blends of this epoxidation product, cured epoxies from the product or the blend, and methods for making the epoxidation product, blends and cured epoxies are also disclosed and claimed. The cured epoxies from the epoxidation product and blends thereof surprisingly exhibit high heat distortion temperature and superior stability to oxidative degradation.

Description

EPOXIDATION PRODUCTS OF 1,3, 5-TRIS (4 ' -HYDROXYPHENYL)BENZENES

Cross-Reference To Related Applications

Reference is hereby made to the commonly owned and concurrently filed applications of Aslam, et al. , Serial

Nos. and (Attorney Docket Nos. ATC- 0029 and CMS 512110-2037; and ATC-0030 and CMS 512110-2038) , the disclosures of which are hereby incorporated herein by reference.

This application discloses and claims subject matter disclosed in copending U.S. patent application, Serial No. 07/819,166, filed January 8, 1992, and is a continuation-in- part application thereof.

FIELD OF THE INVENTION

This invention relates to epoxidation products of an epihalodydrin and a 1,3, 5-tris (4 ' -hydroxyphenyl)benzene (THPB) , blends of epoxides containing the epoxidation products, cured epoxy of the products or blends, and, to methods for preparing the products, blends and cured epoxy. The epoxidation products, especially the blends, and cured epoxy, of the present invention exhibit superior properties including an average epoxide functionality of from about 2.5 to about 6, or at least about 70% of the theoretical for the number of hydroxyls, excellent heat distortion temperature (HDT) and, improved stability to degradation, particularly, to oxidative degradation.

BACKGROUND OF THE INVENTION

1,3,5 tris (4 ' -hydroxyphenyl)benzene (THPB) falls into the class of compounds known as trisphenyls . Trisphenyls have been recognized as useful intermediates in the preparation of more complex organic structures. 1,3,5- tris ( '-hydroxyphenyl) benzenes such as THPB and its derivatives are known, as are methods for preparing them. For instance, in Beilstein, E II _ , 1115 (1921) the treatment of 4-methoxyacetophenone (4-MAP) with sulfuric acid to obtain 1, 3, 5-tris (4 ' -methoxyphenyl)benzene (4-MAP trimer or TMPB) (20% yield) is reported. This compound was demethylated with concentrated hydrochloric acid to yield THPB.

In Chimia, 12, 143 (1958) and 13., 105 (1959) THPB is reported as formed by the trimerization of 4- haloacetophenone, where the halogen is either bromine or chlorine, in the presence of potassium pyrosulfate and sulfuric acid. This reaction results in 1,3, 5-tris (4 ' - halophenyl)benzenes. These halogen-containing trimers were treated with sodium hydroxide and converted to THPB. M. H.

Karger et al., .T. Orσ. Chem.. 3 L, 540 (1971) reported that anisole and acetyl ethanesulfonate affords 4-MAP (46% yield) and TMPB (41% yield) . Subsequent to anisole acetylation, trimerization is effected and is apparently catalyzed by methanesulfonic acid.

Further reports of trimerizing acetophenones, preparing trisphenyls, or of preparing tri(hydroxybenzyl) enzenes may be found in R. E. Lyle et al, J. Amer. Chem. Soc. , 5. 5959 (1953); G.P. Shainin et al. , Zhurnal Prikladnoi Khimii, 43, 1642 (1970); P. Milart et al.. Synthesis PP. 328-29 (1984); Starnes et al., U.S. Patent No. 3,458,473 issued July 29, 1969; Starnes, U.S. Patent No. 3,644,538 issued February 22, 1972; Rocklin et al. , U.S. Patent No. 3,026,264 issued March 20, 1962; Jaffe et al., U.S. Patent No. 3,053,803 issued September 11, 1962 and, Zimmerman et al. , German Patent No. 258,929 issued August 10, 1988. Thus, 1,3,5-tris (4 ' -hydroxyphenyl)benzenes such as THPB and derivatives of THPB and methods for obtaining these compounds are known. The two applications of Asla et al. which are incorporated by reference also relate to methods to obtain THPB and its derivatives from 4- hydroxyacetophenone (4-HAP) . For instance, one application describes for the direct trimerization of 4-HAP (without converting it to an alkoxy) by contacting 4-HAP with aniline and/or an aniline derivative. The other application provides methods for producing THPB and its derivatives from trimerizing 4-substituted acetophenones, such as 4- acetoxyacetophenone, O- (4 ' -acetopheny1 ) -N, N ' - dimethylthiocarbamate, 4-methanesulfonoxyacetophenone. THPB is obtained by cleaving the electron withdrawing group from the 4' position of the trimer by hydrolysis.

However, before now the epoxidation products prepared by the reaction of a epihalohydrin and the disclosed 1,3,5- tris (4 ' -hydroxyphenyl) enzenes have not been known, taught or suggested.

The term "epoxide" is generally used to refer to resins which contain an epoxy group, that is, a group consisting of an oxygen radical linked to two carbon atoms which are, in turn, linked to each other in some other way. Epoxide resins are generally made by the condensation of polyfunctional phenols such as dihydric phenols and either an epihalohydrin such as epichlorohydrin, or a dihalohydrin such as glycerol dichlorhydrin.

Freeman et al. , U.S. Patent No. 2,824,855 issued February 25, 1958 is directed to the use of polyfunctional phenols, such as dihydric phenols in the formation of the epoxide resins. The use of trisphenols is not taught or suggested by Freeman et al . The dihydric phenols of Freeman et al., it is submitted, suggest the use of a bisphenol, resorcinol or naphthalene compound, not a 1, 3, 5-tris ( ¹- hydroxyphenyl)benzene.

Schwarzer, U.S. Patent No. 2,965,611 issued December 20, 1960 is directed to polyphenol glycidyl ethers and to resins which may be prepared from the polyphenols. The polyphenols of Schwarzer have two hydroxyaryl groups attached to the internal, or non-terminal carbon atom of a propane chain and at least one hydroxyaryl group attached to the terminal carbon atom of the chain.

Bressler et al. , U.S. Patent No. 3,957,832 issued May 18, 1976 relates to epoxy resins prepared from polyhydroxy- containing compounds. There is no teaching or suggestion in Bressler et al. of the use of triphenyl compounds.

Arnett et al., U.S. Patent No. 4,284,573 issued August 18, 1981 concerns a process for producing glycidyl ethers of phenols which involves a reaction of a phenol with excess epichlorohydrin. The phenols, of Arnett et al. are described as a known class of organic compounds having one or more hydroxyl groups attached to an aromatic mono- or polycyclic hydrocarbon nucleus. The class of compounds includes phenol, alpha- and beta-naphthol, o-,m- or p- chloro-phenyl, alkylated derivatives of phenyl (for example o- m thyl-3, 5-dimethyl-, p-t-butyl- and p-nonylphenol) and other monohydric phenols, as well as polyhydric phenols, such as resorcinol, hydroguinone, phloroglucinol, and bis (4- hydroxyphenyl) -2 ' -hydroxyphenyl methane.

Wang et al. , U.S. Patent No. 4,499,255 issued February 12, 1985 concerns the preparation of epoxy resins which are prepared by the reaction of an excess of an epihalohydrin with a phenolic hydroxyl-containing compound. The phenolic hydroxyl-containing compounds disclosed in Wang are exemplified as phenols, bisphenols, novolac resins, polyvinyl phenols, and the corresponding amine compounds.

Mah, U.S. Patent No. 3,787,451 issued January 22, 1974 and Schrader, U.S. Patent No. 4,394,496 issued July 19, 1983 each relate to polyglycidyl ethers of tris (hydroxyphenyl) alkanes (leucaurin-type phenolics) used in epoxide formation. These publications suggest the use of crosslinkers which are not rigidly linear or planar, in contrast to the specific 1 , 3 , 5-tris ( 4 ' - hydroxyphenyl)benzenes which are used as crosslinkers in this invention and which are rigidly linear and planar.

Massingill, U.S. Patent No. 4,313,886 issued February 2, 1982 is directed to a process for the preparation of liquid epoxy resins by the reaction of an epihalohydrin and a dihydric phenol. Suitable dihydric phenols include hydroquinone, resorcinol, catechol, and bisphenols.

Thus, until now, epoxidation products from the reaction of epihalohydrin with a 1, 3, 5-tris (4 ' -hydroxyphenyl)benzene, particularly the specific 1, 3, 5-tris (4 ' - hydroxyphenyl)benzenes utilized in the present invention, was not known. Also, the epoxidation products from the reaction of epihalohydrin with a mixture containing 1,3,5- tris (4 ' -hydroxyphenyl)benzene and one or dihydric or polyhydric phenol was not known. Furthermore, the resultant epoxidation products, blends and cured epoxy of the present invention display superior features including an average epoxide functionally of from 2.5 to about 6 or at least about 70% of theory based on the number of hydroxyl groups, excellent HDT, and improved stability to degradation, especially to oxidative degradation. Epoxidation products, blends and cured epoxies displaying these surprisingly superior feature were not, before now, known, taught or suggested. Epoxide blends containing the epoxidation product of this invention were not before now known, taught, or suggested. Also, 1,3,5-tris (4'-glycidyloxyphenyl)benzene and a blend of epoxides containing this compound were not, before now, known, taught or suggested.

In fact, the art suggests to the skilled artisan crosslinkers which have a flexible nucleus, for instance, the alkane nucleus of Schrader or Mah. According to Mah and Schrader, by employing crosslinkers having a flexible nucleus, the resultant epoxides have superior high- temperature properties (HDT) . It is thus quite surprising that a crosslinker with a rigid aromatic nucleus such as the specific 1, 3, 5-tris (4'-hydroxyphenyl)benzenes utilized in the present invention would afford epoxides which exhibit excellent HDT, and also, excellent stability to degradation especially to oxidative degradation.

SUMMARY OF THE INVENTION An embodiment of the inventive process is the preparation of an epoxidation product which comprises reacting a 1,3, 5-tris (4' -hydroxyphenyl)benzene compound of formula (I)

with an epihalohydrin of formula (II)

(ID

wherein each R independently is an alkyl group of from about 1 to about 12 carbon atoms, phenyl, or cycloalkyl of from about 3 to about 6 atoms; each X, independent of any other X, is halogen (such as chlorine, bromine, fluorine or iodine) or nitro, each p, independent of any other p, is 0, 1 or 2; each n independent of any other n, is 0, 1 or 2; the sum of n + p for each ring is 0, 1, 2, 3 or 4; X¹ is a halogen such as chlorine or bromine and Y is hydrogen or methyl. The epoxidation product has an average epoxide functionally of from about 2.5 to about 6, or at least about 70% of the theoretical value based on the number of hydroxyls.

In preferred embodiments p and n are zero. It is also preferred that y is H.

The present invention also includes the epoxidation products from the reaction of the specific 1, 3 , 5-tris (4 ' - hydroxyphenyl)benzenes with the epihalohydrin. A preferred epoxidation product is 1 , 3 , 5-tris (4 ' - glycidyloxyphenyl)benzene.

The present invention also includes the epoxidation products from the reaction of epihalohydrin with a mixture containing at least one 1, 3 , 5-tris (4 ' -hydroxyphenyl)benzene and one or more dihydric or polyhydric phenol. The said mixture may be a mixture of the respective phenolic compounds, or a pre-formed copolymer containing residues of the respective phenolic compounds, prior to reacting with the epihalohydrin.

The present invention further provides a blend of epoxides preferably comprising at least 5 percent by weight of the epoxidation product of the present invention. The remainder of such blends preferably comprises a mono- or poly-functional epoxide, or a mixture thereof.

In addition, the present invention provides a cured epoxy product or blend which has been cured, for instance, in air or oxygen.

DETAILED DESCRIPTION The 1,3, 5-tris(4'-hydroxyphenyl)benzenes of formula (I) and the epihalohydrin of formula (II) can be prepared in accordance with the techniques of documents mentioned in the Background of the Invention.

In one embodiment of the present invention, in order to prepare the epoxides, the 1,3,5-tris (4 ' - hydroxyphenyl)benzene of formula (I) is combined in a suitable vessel with an excess, preferably, at least a three-fold molar excess, for instance, at least about a 15 to 30-fold molar excess of the epihalohydrin of formula (II) to form a reaction mixture.

The reaction of the compounds of formulae (I) and (II) is preferably performed under reaction conditions including times and temperatures which will promote the reaction, and, which will not cause significant deterioration of reactants or products. The reaction of the compounds of formulae (I) and (II) can be performed under at least one of two sets of conditions.

In one instance, the contacting is carried out in the presence of a coupling catalyst followed by dehydrohalogenation. Suitable catalysts include benzyltrimethylammonium halides such as the chloride tertiary amines such as benzyldimethyla ine, triethylamine, N,N,N' ,N^! -tetramethyl ethylenediamine and the like; N- ethylmorpholine; trisphenylphosphonium halides such as the chloride, bromide or iodide; triphenylethylphosphonium diethyl phosphate and corresponding ionic salts including phosphonateε, acetates, nitrates and the like. Benzyltrimethylammonium chloride is a preferred catalyst. The catalyst can be present in an amount of 0.5% to 1.5% of the amount of the compound of formula (I) present. Other conditions, when the reaction occurs in the presence of a coupling catalyst, include heating the reactants to a temperature of from about 60° to about 150°C, preferably reflux for about 0.5 to about 2.5 hours, typically about 0.5 to about 1.5 hours, preferably for about an hour. Solvent, such as toleune, methyl ethyl ketone, diethyl ketone, and the like, can also be present.

After sufficient time (at sufficient temperature) has elapsed to achieve sufficient coupling of the "epi" groups of the compound of formula (II) to the hydroxyls of the compound of formula (I) , the mixture is cooled to preferably about 25°-80°C, and, at least three equivalents of caustic per equivalent of compound of formula (I) are added, and the mixture is then stirred for about 0.5 to about 4 hours. Since each molecule of formula (I) has three hydroxyls, the amount of caustic present should be at least a three-fold molar excess over the amount of compound of formula (I) present. A stoichiometric excess of caustic to hydroxyls of compound of formula (I) is preferred. The caustic can be an alkali hydroxide such as NaOH a KOH, or sodium carbonate (Na₂C0₃) or sodium aluminate, or a combination thereof. The caustic brings about dehydrohalogenation. The caustic is preferably added slowly to the reaction mixture. The caustic, for instance, can be 3N NaOH or 30-50% NaOH added slowly to the mixture with azeotropic removal of H₂0. The caustic can also be an alcoholic alkali hydroxide such as NaOH or KOH in ethanol or methanol at reflux. Alternatively, concentrated NaOH (e.g., 3N or greater) in saturated Na₂C0₃, can be added to the reaction mixture to bring about dehydrohalogenation. The caustic addition can be repeated to provide for sufficient dehydrohalogenation.

In particular, the caustic addition can be accomplished by adding the appropriate amount of caustic to the reaction mixture and stirring (preferably at about 40-50°C) . The addition and stirring can take about 0.5 to about 3 hours preferably about one hour. The stirring continues after the addition for a sufficient time; and the resulting mixture is then allowed to stand to permit the organic and aqueous phases to separate. The aqueous phase is discarded and the organic phase is again stirred and brought to a temperature of about 25 to about 80°C, preferably about 40-50°C. At least three equivalents of caustic per equivalent of compound of formula (I) are again added slowly and the stirring is continued thereafter. This repetition of the caustic addition can take about 0.5 to about 4 hours, preferably about an hour. After the caustic addition is completed, the aqueous phase is again removed and the organic phase is washed preferably with water which is made slightly acidic, by the addition of for instance, acetic acid. The organic phase is then washed with water until the eluent has a neutral pH. When the neutral pH has been achieved, the organic phase is distilled, for instance, in vacuo. to remove traces of water and unreacted reactants such as epihalohydrin. As a result

« of procedures such as these, an epoxidation product such as 1,3,5-tris(4'-glycidyloxyphenyl)benzene can be obtained, especially when the compound of formula (I) is 1,3,5- tris (4 '-hydroxyphenyl)benzene (THPB) .

Alternatively, contacting of compounds of formulae (I) and (II) is carried out in a one pot process in the presence of an aqueous base in the absence of coupling catalysts and solvents and the dehydrohalogenation step is carried out at an elevated temperature in the presence of a solvent and preferably, with the further addition of aqueous base. The aqueous base, for instance NaOH or KOH, is preferably present in a molar excess with respect to the compound of formula (I) . More particularly, the aqueous base is present in at least a three to nine-fold molar excess of the amount of compound of formula (I) present. In this instance the compounds of formulae (I) and (II) are mixed and moderately heated with stirring until these starting materials are dissolved in each other. The temperature is then raised to about 80° to about 100°C preferably about 90°C, and the base is added portionwise and slowly with stirring. For instance, over the course of about an hour about 50% to about 70%, preferably about 60%, of the base is added. The solvent is then added to the reaction mixture and the base addition continued thereafter. The solvent is preferably a solvent or solvent mixture having the characteristics of methylethyl ketone/toluene mixtures. Such solvent systems include diethyl ketone/toluene, diethyl ketone/xylene, cyclohexanone/toluene and methylisobutyl ketone by itself. In the solvent mixtures, the ketone to toluene or xylene weight ratio is about 1.5 to about 5, typically about 2 to about 4, and preferably about 3 parts by weight ketone per part toluene or xylene. The solvent to compound of formula (I) weight ratio is about 40 to about 125, usually about 50 to about 100, and preferably about 70 to about 100 parts by weight of solvent per 100 parts of compound of formula (I) .

Following the solvent addition, the temperature of the reaction mixture decreases to about 75° to about 85°C. After the base addition is completed, the reaction mixture is heated with stirring, at preferably about 75° to about 85°C for about 1.0 to about 2.0 hours. Solvent and water are then added resulting in a brine formed at the bottom of the mixture. The brine and volatiles are removed from the mixture, leaving the epoxidation product.

Thus, this procedure is a one pot process comprising reacting compounds of formulae (I) and (II) essentially in the absence of coupling catalysts and solvents and in the presence of aqueous base, preferably at least about 3 to about 9 equivalents of base per equivalent of compound of formula (I) ; adding more aqueous base, preferably about 6 equivalents of base per equivalent of compound of formula (I) , and adding the methylethyl ketone/toluene type solvent or solvent mixture; and dehydrohalogenating (with the additional base and solvent or solvent mixture present, preferably by heating with stirring) . The epoxidation product can then be recovered. In the inventive process, products containing more or less monomeric epoxides or more or less polymers, preferably oligomers, can be produced by using epihalohydrin to 1,3,5- tris (4 ' -hydroxyphenyl)benzene mole ratios of from about 3 to about 30:1. At the low end of this range, for instance mole ratios of about 3.0 to about 4.5:1, the product will be almost completely or predominantly oligomers, and at mole ratios of about 15 to about 30:1, the content and average molecular weight of oligomers in the product will be relatively low. Even higher mole ratios (greater than 30 :1) can be used when products consisting predominantly of monomeric epoxides are desired. A preferred mole ratio is about 18 to about 27:1.

Thus, in addition to monomeric epoxidation products, the present invention also contemplates polymeric epoxidation products which are preferably oligomeric, such as dimers, trimers, tetramers, and the like. These polymeric epoxidation products are formed from the monomer via oxirane/-OH adduction during the epoxidation reaction. The polymeric epoxidation products are exemplified by the l,3,5-tris(4' -hydroxyphenyl)benzene-derived products illustrated in formula (III) , below, wherein, q is zero or a positive integer, typically 0 to 10, preferably 0 to 5, and, most preferably 0, 1, or 2. The R_p, X_n and Y groups can be present such that similar polymers can be formed from the other compounds within the scope of formulae (I) and

(II) . Also, other polymers may be present in the epoxidation product. These other polymers can be branched.

For instance, more than two of the epoxide groups in a singe monomeric molecule can be reacted with hydroxyl groups.

These other polymers are usually present in small amounts.

In another embodiment of the present invention, epoxides may be prepared by reacting epihalohydrin with a mixture of phenolic compounds such as, for example, a 1,3,5- tris (4 '-hydroxyphenyl)benzene, and one or more dihydric or polyhydric phenol. Examples of useful dihydric or polyhydric phenols include bisphenol A, phenolic novolac resins, e.g., bisphenol F, tetrakis (4-hydroxyphenyl) ethane, and the like. The amount of the 1,3, 5-tris (4 ' -hydroxyphenyl)benzene in the mixture or the copolymer is generally about 0.5-20 weight %, typically about 2-15 weight %, and preferably about 5-10 weight %. The mole ratio of epihalohydrin to the total phenols (including the 1,3, 5-tris (4 '-hydroxyphenyl)benzene) in the mixture or copolymer, in the epoxidation reaction is kept about the same as described above for the preparation of epoxide from the reaction of epihalohydrin and 1,3,5- tris (4' -hydroxyphenyl)benzene. Such epoxies which contain residues of both the 1,3, 5-tris (4' -hydroxyphenyl)benzene and other dihydric or polyhydric phenols, may be then cured to provide resins with excellent HDTs. Additionally, the choice of the dihydric or polyhydric phenol in the mixture or copolymer may advantageously be used to tailor the properties of the resulting epoxy material.

The skilled artisan can vary the conditions for forming an epoxidation product of the invention, taking into consideration such factors usually considered by such an artisan, for example, the scale of the reaction.

The epoxidation product of this invention prior to curing, may be blended with various other materials. The epoxidation product can be admixed with other epoxides. For example, it may be admixed with epoxy novolac resins or with diglycidyl ethers of dihydroxy compounds, for instance, to increase the cross-linking density of the cured product. The epoxidation product of the invention can also be blended with mono- or poly-functional compounds such as phenyl glycidyl ether, allyl glycidyl ether, butyl glycidyl ether, cyclohexene monoxide, alkylene oxides such as butylene oxide, propylene oxide, octylene oxide and the like, butadiene dioxide, 4,4'-isopropylidene diphenol, diglycidyl ether, cyclopentadiene dioxide, vinyl cyclohexene dioxide, bis (2, 3-epoxycyclopentyl) ether, diglycidyl phthalate, diglycidyl amine, and the like.

When the epoxidation product of the invention is blended, for instance with a mono- or poly-functional epoxide or mixtures thereof, the epoxidation product of the present invention is present in an amount of at least about 5% to about 95% by weight, typically at least about 10% to about 95% by weight, preferably at least about 25% to about 95% by weight, and more preferably at least about 50% to about 95% by weight. The epoxidation product of this invention is useful in the same areas as other epoxy resins. However, the epoxidation product, and blends thereof, especially epoxy blends, and cured epoxy products from the epoxidation product and blends of this invention, are especially useful for high temperature and highly oxidative conditions such as heat shields and nose cones, engine/motor parts (jet, rocket, or automobile) , circuit boards, pipe, and chemical holding-tanks, pressure-spheres, hoods, stacks and the like. Other uses include potting, encapsulation, high performance coatings, foams, castings, toolings, caulking compounds, composites such as fiber-resin composites, laminates, adhesives, molding compounds and the like.

The epoxidation product and blends of the invention can be cured by typical curing agents including methylene diamine, m-phenylenediamine, and mixtures thereof; o- and p-phenylenediamines; benzidine; diaminodiphenylsulfone; 2,6- diaminopyridine ; benzyldimethylamine ; etramethylethylenediamine; N-methylmorpholine; diethylenetriamine; triethylenediamine; tetramethylguanidine; dicyandiamide; dimethylethanolamine; diethanolamine; trialkylamines, such as triethylamine, tripropylamine and tributylamine; 4-picoline; BF₃ complexes such as BF₃ monoethyla ine; borates, such as tricresyl borate; anhydrides, such as Nadic methyl anhydride, hexahydrophthalic anhydride, dodecenyl succinic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, glutaric anhydride, pyromellitic dianhydride, trimellitic anhydride, tetrahydrophthalic anhydride, chlorendic anhydride, polysebacic polyanhydrides, polysulfides, polyazalaic anhydride, benzophenonetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, and the like and mixtures thereof. Alkylene diamines, polyalkylene amines, aromatic diamines, anhydrides, melanine/formaldehyde resins and the like are preferred curing agents or catalysts.

The epoxidation product and blends thereof of the present invention can be cured over varying temperatures and times, depending upon the agent used and properties desired. For instance, curing times and temperatures of about 1 to about 3 hours, preferably about 2 hours, at about 200 to about 260° preferably at about 230°C can provide excellent properties with curing agents such as methylene diamine, meta-phenylenediamine, benzidine diaminodiphenylsufone, BF₃ complexes, maleic anhydride-tri-mellitic anhydride mixtures, hexahydrophthalic anhydride-trimellitic or pyromellitic anhydride mixtures, and phthalic anhydride mixed with tri ellitic, or pyromellitic anhydride. Anhydrides, such as cyclopentanetetracarboxylic acid dianhydride or benzophenonetetracarboxylic acid dianhydride mixed with maleic, phthalic, or hexahydrophthalic anhydrides, can also be used. Alternately, high melting anhydrides can be used alone, especially if they are milled into the resin to achieve complete dispersion.

A moderate cure is obtained at about 2 hours at about 120°C with amines such as aromatic or tertiary amines, BF₃ complexes, borates, and lower melting anhydrides. Step curing can also provide excellent properties. For instance, steps of about 12 to about 18 hours, preferably about 16 hours, at about 60° to about 100°C, preferably about 80° to about 85°C; plus about another 12 to about 18 hours, preferably about 16 hours, at about 120° to about 200°C, preferably about 160° to 170°C; and optionally, about an additional 2 to about 6 hours, preferably about 4 hours, at about 200° to about 260°C, preferably about 220° to about 230°C. The shortest possible curing times usually produce optimum properties in the cured epoxy. The curing agent and epoxidation product or blend are typically present in stoichiometric amounts .

Examples of 1,3, 5-tris (4 ' -hydroxyphenyl ) benzenes (or 1, 35-tris (4 ' -hydroxyaryl) benzenes) which can be used to make epoxidation products and cured epoxidation products in accordance with the invention are:

1,3, 5-tris ( ' -hydroxyphenyl) benzene; 1, 3 , 5-tris (3 ' -ethyl, 4 ' -hydroxyphenyl) benzene ; 1,3, 5-tris (3 ' -phenyl, 4 ' -hydroxyphenyl) benzene; l , 3 , 5-tris {2 ' -methyl, 3 ' -c loro, 4 ' - hydroxyphenyl ) benzene;

1,3, 5-tris (3 ' -nitro, 4 ' -hydroxyphenyl) benzene; 1 , 3 , 5 -tris ( 2 ' -ethyl , 3 ' -nitro , 4 ' - hydroxyphenyl ) benz ene ; 1,3,5 -tris ( 2 ' - cyclohexyl , 4 ' -hydroxyphenyl ) benzene;

1,3, 5-tris (3 ' -bro o, 4 ' -hydroxyphenyl) benzene; 1,3, 5-tris (2 ' -propyl,4 ' -hydroxyphenyl) benzene; 1 , 3 , 5 - t ri s ( 2 ' - iodo , 3 ' - ethyl , 4 ^l - hydroxyphenyl ) benzene ; 1,3, 5-tris (3 ' -butyl , 4 ' -hydroxyphenyl ) benzene;

1,3, 5-tris (2 ' -pentyl , 4 ' -hydroxyphenyl) benzene; 1,3, 5-tris ( 2 ' -hexyl , 4 ' -hydroxyphenyl ) benzene ; 1,3, 5-tris (2 ' -heptyl, 4 ' -hydroxyphenyl) benzene ; 1,3, 5-tris (3 ' -methyl, 4 ' -hydroxyphenyl) benzene; 1 , 3 , 5 - tris ( 2 ' - ethyl , 3 ' -nitro , 4 ' - hydroxyphenyl ) benzene ;

1 , 3 , 5 -tris (2 ' -methyl , 3 ' - iodo , 4 ' - hydroxyphenyl ) benz ene ;

1, 3 , 5-tris (3 ' -met yl , 4 ' - hy dr oxy , 5 ' - nit rophenyl ) benzene ;

1 , 3 , 5-tris ( 2 ' -nitro , 4 ' -hydroxy, 6 ' - nit rophenyl ) benzene ;

1, 3 , 5-tris (2 ' -chloro, 4 ' - hy dr oxy , 6 ' - chlorophenyl ) benzene;

1 , 3 , 5-tris (2 ' -methyl , 4 ' -hydroxy, 6 ' - methylphenyl ) benzene ;

1,3, 5-tris (2 ' , 3 ' -dimethyl , 4 ' -hydroxy, 5 ' , 6 ' - diiodophenyl ) benzene;

1,3, 5-tris (2 ' , 3 ' -dibro o, 4 ' -hydroxy, 5 ' , 6 ' - dimethylphenyl)benzene; l,3,5-tris(2 ' ,3 '-dinitro,4' -hydroxy, 5 ' , 6 ' - diethylphenyl)benzene; and l , 3 , 5 - t r i s ( 3 ' - cy c l o p r o py l , 4 ' - hydroxyphenyl)benzene.

The examples of epihalohydrins which can be used to make epoxidation products and cured epoxidation products in accordance with the invention are:

epichlorohydrin ( 1-chloro-2 , 3 -epoxypropane; chloropropylene oxide) ; epibromohydrin (l-bromo-2, 3- epoxypropane ; bromopropylene oxide) ; epifluorohydrin ( 1 , 2-epoxy-3-fluoropropane; fluoropropylene oxide) ; epiiodohydrin (1, 2-epoxy-3-iodopropane; iodopropylene oxide) ;

3-chloro-1, 2-epoxy-2-methyIpropane; 3-bromo-l, 2-epoxy-2-me hyIpropane; 1, 2-epoxy-3-iodo-2-methyIpropane; and

1,2-epoxy-3-fluoro-2-methyIpropane.

Cured epoxidation products of this invention, for instance, cured products from Examples 1 to 10 and 12 to 21 (below) , exhibit superior oxidative stability. For example, when subjected to oxidative conditions such as air at 150°C, cured specimens of epoxidation products of the invention compare favorably to and exceed prior art epoxidation products in terms of exhibiting discoloration and oxidative deterioration. That is, cured specimens of epoxidation products of the invention last as long as, if not longer than, prior epoxidation products before exhibiting discoloration and oxidative deterioration. Without wishing to be bound to any one particular theory, it is believed that this surprising improvement is obtained as a result of the aromatic nucleus of the 1,3,5-tris ( ' - hydroxyphenyl)benzenes used in the formation of expoxidation products of the invention; the aliphatic side chain nucleus of prior art precursor compounds, for example, tri(phenyl) alkanes, used to form prior epoxidation products is more likely subject to oxidative degradation, whereas the aromatic nucleus is not.

The invention may be further illustrated by the following examples, many apparent variations of which are possible without departing from the spirit thereof.

EXAMPLE 1 Synthesis of 1.3.5-tris( '-σlvcidvloxvphenvl)benzene from l,3,5-trls( '-hvdroxyphenyl)benzene(THPB) By Coupllnσ Catalyst

A reaction mixture of 1, 3 , 5-tris (4 ' - hydroxyphenyl)benzene (THPB) (354.4g, 1 mole) and epichlorohydrin (2780 grams, 30 moles) and benzyltrimethylammonium chloride solution (60% soln, 1% THPB) is placed into a flask fitted with a stirrer, thermometer and condenser, The reaction mixture is heated with stirring to reflux for an hour, and then is allowed to cool. After cooling, the reaction mixture is placed in a water bath (50°C) and 1 liter of 3M NaOH in Na₂C0₃ is slowly added with stirring. After the addition, the mixture is stirred at 50°C for one hour. The organic layer is separated from the mixture, placed in a water bath (50°C) and another 1 liter of 3M NaOH in Na₂C0₃ is added with stirring. After the addition, stirring continues for one hour. The organic layer is separated, and washed with dilute aqueous acetic acid, and then with water until neutral. The organic is vacuum distilled whereby water and unreacted epichlorohydrin distill away. The resulting resin is 1,3,5-tris(4 '-glycidyloxyphenyl)benzene. The epoxide functionality is between 2.5 and 6 (at least 70% based on the theoretical number of hydroxyls) .

EXAMPLES 2-10 Preparation of Additional Epoxidation Products From THPB Derivatives Bv Coupling Catalyst

In the same manner as Example 1, epoxidation products are made with the following derivatives of THPB (rather than with THPB) :

2. 1,3,5-tris (3 '-ethyl,4 '-hydroxyphenyl)benzene;

3. 1,3, 5-tris (3 '-phenyl,4 '-hydroxyphenyl)benzene;

4. 1, 3 , 5-tris (2 ' -methyl, 3 ' -chloro, 4 ' - hydroxyphenyl)benzene;

5. 1,3,5-tris (3 '-nitro,4 '-hydroxyphenyl)benzene;

6. 1 , 3 , 5-tris ( 2 ' -ethyl , 3 ' -nitro, 4 ' - hydroxyphenyl)benzene;

7. 1,3,5-tris(2 '-cyclohexyl,4'-hydroxyphenyl)benzene;

8. 1,3, 5-tris (3 ' -bromo,4 '-hydroxyphenyl)benzene; 9. 1,3,5-tris (2 '-propyl,4'-hydroxyphenyl)benzene;and

10. 1 , 3 , 5 - t ri s ( 2 ' - i o do , 3 ' - ethyl , 4 ' - hydroxyphenyl)benzene;

Each of the resultant epoxidation products has an average epoxide functionality between 2.5 and 6 (at least 70% based on theoretical number of hydroxyls) .

EXAMPLE 11 Heat Distortion Temperature (HDT) of Cured Epoxidation Products

The epoxidation products of Examples 1-10 are each mixed with a stoichiometric amount of methylene diamine, shaped into test specimens and cured for 2 hours at 100°C and then 18 hours (overnight) at 180°C. The cured products from the epoxidation products of Examples 1-10 have heat distortion temperatures, by the TMA method, of 240°C to 350°C, which are considered to be excellent heat distortion temperatures. Thus, using rigid, linear and planar crosslinkers this invention provides cured epoxy specimens having excellent heat distortion temperatures.

EXAMPLE 12 Synthesis of 1.3.5-tris(4 '-glvcidvloxvphenvl)benzene From 1.3.5-tris(4 '-hvdroxvphenvl)benzene(THPB) Without Coupling Catalyst A reaction mixture of THPB (354.4g, 1 mole) and epichlorohydrin (333.63 grams, 3.6 moles) is heated moderately with stirring until the starting materials are dissolved in each other. The temperature is then elevated to about 90°C, the rate of stirring is increased, and, NaOH (150.5g, 3.77 moles) is added portionwise, as a 25% aqueous solution, over a period of about one hour. After about 60% of the NaOH solution is added, a solvent system consisting of a mixture of methylethyl ketone and toluene (3:1; 354.4 ml, 283.5g) is added to the reaction mixture. The temperature of the reaction mixture decreases to about 85°C following the addition of the solvent system. After the addition of the solvent system, the NaOH addition continues until completed. The reaction mixture then is heated with stirring at about 80°-85°C for about 1.5 hours. More solvent system consisting of the methylethyl ketone/toluene mixture (708.8 ml, 567g) and water (177 ml) are added to the reaction mixture. The concentrated brine at the bottom of the mixture is separated therefrom and solvent and volatiles are removed by vacuum distillation to produce 1,3, 5-tris (4 ' - glycidyloxyphenyl)benzene having an epoxide functionality between 2.5 and 6 (at least 70% based on the theoretical number of hydroxyls) .

EXAMPLES 13-21 Additional Epoxidation Products From THPB Derivatives Without Coupling Catalyst

In the same manner as Example 12, epoxidation products are made with the following derivatives of THPB (rather than with THPB) :

13. 1,3, 5-tris(3 '-ethyl, 4 ' -hydroxyphenyl)benzene;

14. 1,3, 5-tris(3 '-phenyl,4 '-hydroxyphenyl)benzene;

15. 1 , 3 , 5-tris (2 ' -methy 1 , 3 ' -chloro, 4 ' - hydroxyphenyl)benzene;

16. 1,3, 5-tris (3 ' -nitro, 4' -hydroxyphenyl)benzene;

17. 1 , 3 , 5-tris ( 2 ' -ethyl , 3 ' -nitro , 4 ' - hydroxyphenyl)benzene;

18. 1,3,5-tris(2 '-cyclohexyl,4'-hydroxyphenyl)benzene;

19. 1,3,5-tris (3 ' -bromo, 4 ' -hydroxyphenyl)benzene;

20. l,3,5-tris(2'-propyl, 4'-hydroxyphenyl)benzene;and 21. 1 , 3 , 5-tris (2 ' - iodo , 3 ' -ethyl , 4 ' - hydroxyphenyl)benzene;

Each of the resultant epoxidation products has an average epoxide functionality between 2.5 and 6 (at least 70% based on the theoretical number of hydroxyls) .

EXAMPLE 22

Heat Distortion Temperature of Cured Epoxidation Products The epoxidation products of Examples 13-21 are each mixed with a stoichiometric amount of methylene diamine, shaped into test specimens, and cured for 2 hours at 90°C, 4 hours at 165°C and 16 at 200°C. The cured products from the epoxidation products of Examples 13-21 have heat distortion emperatures, by the TMA method, of 240°C to 350°C, which are considered to be excellent heat distortion temperatures. Thus, by the "no coupling catalyst" or "one pot" process, this invention, using rigid, linear and planar crosslinkers, provides cured epoxy specimens having excellent heat distortion temperatures.

EXAMPLE 23

Synthesis of Epoxidation Product from reacting epichlorohvdrin with a mixture of 1.3.5-tris(4 '- hydroxyphenyl)benzene(THPB) and bisphenol A;

This epoxy product is synthesized from a mixture of 1,3,5-tris (4 '-hydroxyphenyl)benzene and bisphenol A (5:95 weight %) , and epichlorohydrin in a 1:2 equivalence ratio

(of epichlorohydrin to total phenolic hydroxyls) as described in Example 1. The reaction mixture is worked up in a similar manner to isolate the product containing the residues of 1,3, 5-tris (4 '-hydroxyphenyl)benzene and bisphenol A in its backbone. The product may be cured by following a procedure similar to that described in Example

11, and its HDT may be measured in a similar manner.

Having described in detail preferred embodiments of the present invention, it is to be understood that the invention defined by the appended claims is not to be limited by particular details set forth in the above description as many apparent variations thereof are possible without departing from the spirit of the present invention.

Claims

WHAT IS CLAIMED IS:

1. An epoxidation product of a 1,3, 5-tris (4' hydroxyphenyl)benzene derivative of formula (I)

and an epihalohydrin of formula (II) :

(ID wherein: each R independently represents an alkyl group of from 1 to about 12 carbon atoms, phenyl or cycloalkyl of from 3 to about 6 carbon atoms;

each X independently represents halogen or nitro; each p independently is 0, 1 or 2; each n independently is 0, 1 or 2; the sum of n+p for each ring is 0 to 4; X¹ is Cl, Br, I or F; Y is H or CH₃; and

said epoxidation product having an average epoxide functionality of from about 2.5 to about 6.0, or at least about 70% of theoretical for the number of available hydroxyls, whichever is greater.

2. The epoxidation product of claim 1 wherein X¹ is Cl or Br.

3. The epoxidation product of claim 2 wherein p and n are 0.

4. The epoxidation product of claim 3 wherein Y is H.

5. The epoxidation product of claim 3 which is 1,3,5- tris (4 ' -glycidyloxyphenyl)benzene.

6. A blend of epoxides comprising at least 5 weight percent of the epoxidation product of claim 2, the remainder comprising a mono- or a poly-functional epoxide, or mixtures thereof.

7. The cured epoxy blend of claim 6.

8. The blend of claim 6 wherein the epoxidation product is 1, 3, 5-tris (4 ' -glycidyloxyphenyl)benzene.

9. The cured epoxy blend of claim 7 wherein the epoxidation product comprises 1 , 3 , 5-tris (4 ' - glycidyloxyphenyl)benzene.

10. The epoxidation product of claim 2 wherein the derivative of formula I) is 1, 3, 5-tris (4 ' - hydroxyphenyl)benzene.

11. A blend of epoxides comprising at least 5 weight percent of the epoxidation 'product of claim 10, the remainder comprising a mono- or poly-functional epoxide, or mixtures thereof.

12. The cured epoxy blend of claim 11.

13. A process of preparing an epoxidation product which comprises (i) forming a reaction mixture by contacting a 1,3,5-tris(4'-hydroxyphenyl)benzene derivative of formula (I) :

with epihalohydrin of formula (II)

(ID wherei : each R independently represents an alkyl group of from 1 to about 12 carbon atoms, phenyl or cycloalkyl of from 3 to about 6 carbon atoms;

each X independently represents halogen or nitro; each P independently is 0, 1 or 2; each n independently is 0, 1 or 2; the sum of n+p for each ring is 0 to 4; X¹ is Cl, Br, I or F; Y is H or CH₃; said epihalohydrin of formula (II) being present in at least a three-fold molar excess of the amount of the 1,3,5- tris (4 ' -hydroxyphenyl)benzene derivative of formula (I) present; said contacting being either in the presence of aqueous base and in the absence of a coupling catalyst or in the presence of a coupling catalyst; and (ii) adding base to the reaction mixture to effect sufficient dehydrohalogenation.

14. The process of claim 13 wherein X¹ is Cl or Br.

15. The process of claim 14 further comprising recovering product after step (ii) .

16. The process of claim 15 wherein a coupling catalyst is present in step (i) .

17. The process of claim 16 wherein the base in step (ii) is KOH or NaOH in methanol or ethanol, or, the base is

NaOH in Na₂C0₃ solution; and, the recovery of product comprises separating an organic phase from the reaction mixture, and acidifying, neutralizing and then distilling the organic phase; and, p and n are 0 and the epoxidation product is 1, 3, 5-tris (4 ' -glycidyloxyphenyl)benzene.

18. The process of claim 15 wherein p and n are 0.

19. The process of claim 18 wherein the epoxidation product comprises 1, 3, 5-tris (4 ' -glycidyloxyphenyl)benzene.

20. The process of claim 16 further comprising curing said product.

21. The process of claim 16 further comprising forming a blend of epoxies by mixing said product with a mono- or a poly-functional epoxide, or mixtures thereof; said blend containing at least 5 weight percent of said product.

22. The process of claim 21 further comprising curing the blend.

23. The process of claim 19 further comprising curing the blend.

24. The process of claim 19 further comprising forming a blend of epoxies by mixing said product with a mono- or poly-functional epoxide, or mixtures thereof; said blend containing at least 5 weight percent of said product.

25. The process of claim 24 further comprising curing the blend.

26. The process of claim 15 wherein step (i) is in the absence of coupling catalyst, and in the presence of aqueous base; and, a methylethyl ketone/toluene type solvent is present in step (ii) .

27. The process of claim 26 wherein the epoxidation productcomprises1,3,5, -tris (4 ' -glycidyloxyphenyl)benzene.

28. The process of claim 27 further comprising forming a blend of epoxies by mixing said product with a mono- or poly-functional epoxide, or mixtures thereof; said blend containing at least 5 weight percent of said product.

29. The process of claim 27 further comprising curing the product.

30. The process of claim 29 further comprising curing the product.

31. The process of claim 15 wherein the 1,3,5-tris (4 hydroxyphenyl)benzene derivative is 1,3, 5-tris (4 hydroxyphenyl)benzene.

32. The process of claim 31 further comprising forming a blend of epoxies by mixing said product with a mono- or a poly-functional epoxide, or mixtures thereof; said blend containing at least 5 weight percent of said product.

33. The process of claim 31 further comprising curing the product.

34. The process of claim 32 further comprising curing the product.

35. An epoxidation product of a 1,3, 5-tris(4'- hydroxyphenyl)benzene derivative of formula (I) :

a phenol of formula ( II )

(II) and an epihalohydrin of formula (III) :

wherei : each R independently represents an alkyl group of from 1 to about 12 carbon atoms, phenyl or cycloalkyl of from 3 to about 6 carbon atoms; each X independently represents halogen or nitro; each p independently is 0, 1 or 2; each n independently is 0, 1 or 2; the sum of n+p for each ring is 0 to 4; X¹ is Cl, Br, I or F;

Y is H or CH₃; and

36. The epoxidation product of claim 35 wherein X¹ is Cl or Br.

37. The epoxidation product of claim 36 wherein p and n are 0.

38. The epoxidation product of claim 37 wherein Y is H.

39. The epoxidation product of claim 38 further cured.