MXPA97002582A - Modifiers of the hardening of epoxided cauchomonohidroxilates, for epoxy resins - Google Patents

Abstract

The present invention relates to a hardened epoxy resin composition, characterized in that it comprises a) a curable aromatic or cycloaliphatic epoxy resin, b) a monohydroxylated epoxidized polydiene polymer, which comprises at least two polymerizable ethylenically unsaturated hydrocarbon monomers, where at least one is a diene monomer which produces unsaturation appropriate for the epoxidation, and wherein the polymer contains from 0.5 to 7 milliequivalents (meq) of epoxy per gram of polymer, and c) a curing agent.

Description

MODIFIERS OF RUBBER HARDENING, EPOXIDED MONOHYDROXYLED, FOR EPOXY RESINS DESCRIPTION OF THE INVENTION The present invention relates to the use of epoxidized monohydric polydiene polymers as hardening modifiers for aromatic or cycloaliphatic epoxy resins. The present invention also relates to mixtures of such epoxy resins and epoxidized monohydroxylated polydiene polymers, useful for structural adhesives, coatings, especially primers, electrical applications such as bearings, coatings, encapsulators, filler compounds, welding masking compounds, and applications in laminates and construction such as floor covering, civil engineering, concrete repair and consolidation, secondary containment tancaje, grouts, sealants, and polymeric concrete, and structural compounds, and tools. Cured epoxy resins are typically strong, rigid and hard materials. In addition, due to their chemical constitution they adhere strongly to many substrate materials. These REF: 24431 physical characteristics of cured epoxy resins make them useful in a wide range of applications. One disadvantage of cured epoxy resins is their brittle character. When subjected to impact, cyclic stresses, thermal stresses, or differences in adhesive-substrate expansivities, epoxy resins tend to fail at relatively low applied stresses, in a brittle manner. The goal of much effort in this area has been to improve the tenacity, or equivalently established, energy required to fracture epoxy resins. Improvements in this regard lead to mechanically superior materials. Therefore, it could be advantageous if an epoxy resin composition with increased toughness could be prepared. Importantly, the desired increase in toughness should occur with little or no sacrifice in the beneficial mechanical properties of epoxy resins such as strength, stiffness, hardness and adhesion. One route of this improvement is to incorporate a rubber within the epoxy matrix. Increases in toughness by incorporating a rubber phase into an epoxy matrix are known. Carboxy functional group rubbers, as described in U.S. Patent No. 3,823,107, have been used as modifiers for epoxy resins. These modifiers with carboxyl functional group suffer, however, the disadvantage that they must be previously reacted with the epoxy resin before being cured, so that useful improvements in properties are achieved. Polymers grafted with anhydride or acid functional groups, as described in U.S. Patent No. 5,115,019 have been used as modifiers for epoxy resins. These rubbers also suffer from the disadvantage that pre-reaction is required. In addition, in some cases the mixing of the solvent and the formation of emulsions of the polymeric modifier are required. The process required to supply these polymers has the additional disadvantage that the resulting dispersion of the rubber in the epoxy is sensitive to the process parameters, such as the temperature and the cutting speed during mixing, the length of mixing time, and the type and amount of solvent, so that inconsistent products with varying properties are produced. A second disadvantage of epoxy resins is their propensity to absorb water, which leads to decreased vitreous transition temperatures, and reduced mechanical properties. The aim of the efforts in this area has been to reduce the amount of water absorbed by the incorporation of strongly hydrophobic materials within the epoxy resins. The epoxidized, low viscosity polydiene polymers are known to be used in the modification of epoxy resins. Such polymers are described in U.S. Patent No. 5, 229,464. These polymers are liquid epoxidized rubbers. Compatible blends of the polymers of the above-described patent and of epoxy resins are described in U.S. Patent No. 5,332,783 which is incorporated by reference herein. The blends described in the aforementioned patent application have the advantage that their compatibility with epoxy resins is limited. Its limited compatibility does not extend to a wide range of epoxy resins and curing agents. Compatibility curing agents are required. These have the additional disadvantage that even when they are marginally compatible, these polymers do not produce final, cured epoxies having increased tenacity. In addition, compatibilization curing agents lead to cured epoxy resins having significantly reduced stiffness, which makes them applicable only in limited applications. The monohydroxylated epoxidized polymers of the present invention possess dual functionality, since epoxy and hydroxyl groups are present and produce cured epoxy resin compositions having a superior balance of properties. The monohydroxylated polymers of the present invention provide an improved balance of the properties over the previous technology, in which greater tenacity is achieved. time that resistance and rigidity is maintained higher. Therefore, the compositions of the present invention show wide utility. In addition, the monohydroxylated epoxidized polymers of the present invention are simply mixed with epoxy resins before curing without pre-reaction or with the required solvent. In addition, it is anticipated that the aliphatic character of these epoxidized and monohydroxylated polydiene polymers will reduce the amount of water absorbed by the rubber-modified epoxy resin, and also will provide materials of relatively low dielectric constant. The present invention relates to a stiffened or hardened epoxy resin composition comprising: a) a curable aromatic or cycloaliphatic epoxy resin, b) a monohydroxylated epoxidized polydiene polymer, which comprises at least two ethylenically unsaturated hydrocarbon monomers, polymerizable, wherein at least one is a diene monomer which produces unsaturation appropriate for the epoxidation, and wherein the polymer contains from 0.5 to 7 milliequivalents (meq) of epoxy per gram of polymer, and c) a curing agent. These monohydroxylated polymers can contain up to 60% by weight of at least one vinyl aromatic hydrocarbon, preferably styrene. The polymers may be block copolymers or randomly copolymerized copolymers of at least two polymerizable ethylenically unsaturated hydrocarbon monomers, wherein at least one is a diene monomer which produces unsaturation appropriate for the epoxidation. These polymers have a molecular weight in the range of 1000 to 300,000, preferably in the range of 1,000 to 100,000, and more preferably in the range of 1,000 to 20,000 and are preferably liquid. These polymers are generally epoxidized, such that they contain from 0.5 to 7 milliequivalents (meq) of epoxy per gram of polymer.

Preferred monohydroxylated polydiene polymers of the present invention have the structural formula: (I) (H0) x-A-S2-B- (0H) and wherein A and B are the polymer blocks, which may be homopolymer blocks of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomers, or copolymer blocks of diolefin monomers and monoalkenyl aromatic hydrocarbon monomers. These polymers can contain up to 60% by weight of at least one vinyl aromatic hydrocarbon, preferably styrene. Preferably, The A blocks must have a higher concentration of aliphatic double bonds, more highly substituted, than the B blocks have. In this way, the A blocks have a higher concentration of di-, tri-, or tetra unsaturation sites -substituted (double aliphatic bonds) per block mass unit than that with the B blocks. This produces a polymer wherein the easiest epoxidation occurs in blocks A. Blocks A have a molecular weight in the range of 100 to 6,000, preferably in * the interval of 500 to ,000, and more preferably in the range of 1,000 to 3,000, and B-blocks have a molecular weight in the range of 1,000 to 15,000, preferably in the range of 2,000 to 10,000, and more preferably in the range of 3,000 to 6,000. S is a vinyl aromatic hydrocarbon block which may have a molecular weight in the range of 100 to 10,000. x and y are 0 or 1. Any of x or y must be 1, but only one at a time can be 1. z is 0 or 1. Block a or block B can be stuck with a Ir., Inibloque of a polymer of a different composition having a molecular weight in the range of 50 to 1000, to compensate for any initiation, tapering due to unfavorable copolymerization rates, or to the difficulties of the jamming. The composition according to the present invention may comprise an aromatic epoxy resin. Suitable aromatic epoxy resins include glycidyl ethers prepared by the reaction of the epichlorohydrin with an aromatic compound containing at least one hydroxyl group, carried out under alkaline reaction conditions. The epoxy resin products obtained when the compound containing the hydroxyl group is bisphenol'-A, are represented by the following structure, wherein n is zero or a number greater than 0, suitably in the range of 0 to 10, preferably in the range of 0 to 2. ll «Other suitable epoxy resins can be prepared by the reaction of epichlorohydrin with di- and trihydroxy-phenolic, mononuclear compounds, such as resorcinol and phloroglucinol, polynuclear polyhydroxy-phenolic compounds selected, such as bis (p-hydroxyphenyl) methane and 4,4-dihydroxybiphenyl, or aliphatic polyols such as 1,4-butanediol and glycerol. The aromatic epoxy resins, suitable for the present compositions, have weights Molecules are suitably within the range of 86 to 10,000, preferably in the range of 200 to 1500. The commercially available epoxy resin EPON Resin 828 (EPON is a trademark), a reaction product of epichlorohydrin and 2, -bis (4). - 25-hydroxyphenylpropane) (bisphenol-A) having a molecular weight of about 400, one equivalent of epoxide (ASTM D-1652) of about 185-192, and an n-value (of the above formula) of about 0.13, is currently The preferred aromatic epoxy resin, due to its low viscosity, mechanical performance, and commercial availability. Other examples of aromatic epoxy resins are liquid resins such as EPON 825, a reaction product of epichlorohydrin and bisphenol-A, with an n-value of about 0.04, and EPON 826, a reaction product of epichlorohydrin and bisphenol- A with an n value of about 0.08, and solid resins such as EPON 1001, a reaction product of epichlorohydrin and bisphenol-A with an n-value of about 2.3, EPON 1002, a reaction product of epichlorohydrin and bisphenol-A with an n value of about 3.4, and EPON 1031, a reaction product of epichlorohydrin and tetraphenyl ethane with an epoxide equivalent weight of about 220. The composition according to the present invention may comprise a cycloaliphatic epoxy resin. A cycloaliphatic epoxy resin component of the composition may be any curable cycloaliphatic resin having, on average, more than one epoxide group per molecule, and may possess substituents that do not materially interfere with the curing reaction. Suitable cycloaliphatic epoxy resins include those made by the oxidation of cyclic polyolefins with a peracid, typically peracetic acid. The main suppliers of appropriate cycloaliphatic epoxy resins are Union Carbide and Ciba Geigy. The resins are marketed by Union Carbide as Cycloaliphatic Epoxides and, more recently, under the trade name CYRACURE. Typical structures for these resins are given in the brochures of Union Carbide "Cycloaliphatic Epoxide Systems", 9/87 and "CYRACURE Cycloaliphatic Epoxides, Cationic UV Curing", 4/92. A particularly preferred cycloaliphatic epoxy resin is ERL-4221 from Union Carbide, also sold as CYRACURE UVR-6110 (3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate). This is also the most widely used epoxy cycloaliphatic resin in the industry today. The epoxidized polydiene polymers of this invention have particularly good compatibility with CYRACURE UVR-6110, making them particularly good hardeners for this resin. Other cycloaliphatic epoxy resins include those having glycidyl ether epoxide groups. Epoxy glycidyl ether resins are typically made by the reaction of a diol or polyol with epichlorohydrin. A particularly preferred glycidyl ether epoxy resin is EPONEX 1510 ("EPONEX" is a trademark) of Shell Chemical Company, made by the reaction of hydrogenated bisphenol-A with epichlorohydrin. Other examples of aliphatic glycidyl ether epoxy resins are those elaborated by the reaction of epichlorohydrin with low molecular weight alcohols such as 1,4-butanediol and 1,6-hexanediol. Epoxy aromatic resins can be used in conjunction with an epoxy resin cycloaliphatic. However, the presence of the aromatic epoxy resins in a formulation may reduce the composition's resistance to degradation by light, so that for certain uses, they may only form a minor portion of the composition. total amount of the epoxy resin. The range of epoxy content, capable of imparting the advantageous properties of the present invention, varies slightly depending on whether this is an aromatic epoxy resin or an epoxy resin. cycloaliphatic, that is to say the curable resin but dominant in the composition. The commentaries herein with respect to the required or preferred polymeric epoxide contents, the polymeric vinyl aromatic hydrocarbon levels, the curing agents, the additional components of the composition, etc., are made in relation to either a resin composition. aromatic epoxy or a cycloaliphatic epoxy resin composition, which should be understood to indicate a composition in which the specific resin is the predominant epoxy resin. If equal amounts of each epoxy resin are present, then any group of comments are applicable. The monoepoxy resins can also be used at low levels as reaction diluents, to reduce the viscosity. Polymers containing ethylenic unsaturation can be prepared by anionically copolymerizing one or more olefins, particularly diolefins, by themselves or with one or more alkenyl-aro-hydrocarbon monomers. The copolymers can, of course, be randomized, tipped, block terminated or a combination thereof. The diene-containing polymers, which have residual unsaturation suitable for epoxidation, can also be obtained by other polymerization means, such as by cationic polymerization or free-radical polymerization. Using the cationic polymerization, monomers such as the substituted 1-butenes, 1-pentenes and substituted dienes, such as isoprene and butadiene can be copolymerized. As the cationic polymerization, the growing cationic polymerization allows the copolymers to be block copolymers having the residual diene double bond, located within the polymer. The dienes can be polymerized together with acrylic monomers by initiation with a free radical initiator, such as a peroxide such as AIBN. For pressure sensitive adhesive applications, monomers such as n-butyl acrylate, 2-ethylhexyl acrylate and isoprene may also be used, and other modifying monomers, such as acrylic acid or sodium acrylate, may also be used. -hydroxy-ethyl. Other polymerization methods including coordination / insertion mechanisms such as Ziegler-Natta polymerizations, metallocene polymerizations, and metathesis polymerizations can be used to make diene-containing polymers. Polymers containing ethylenic unsaturation or aromatic and ethylenic unsaturation can be prepared using anionic initiators or polymerization catalysts. Such polymers can be prepared using bulk, solution or emulsion techniques. When polymerizing at a high molecular weight, the polymer containing at least ethylenic unsaturation will be recovered in general as a solid, such as a piece or cluster, a powder, a pellet or the like. When polymerized at a low molecular weight, it can be recovered as a liquid. In general, when using anionic techniques in solution, copolymers of conjugated diolefins, optionally with vinyl aromatic hydrocarbons, are prepared by contacting the monomer or monomers to be polymerized, simultaneously or sequentially with an anionic polymerization initiator such as Group IA metals, their alkyls. amides, silanolates, naphthalides, biphenyls or anthracenyl derivatives. It is preferred to use an organic alkali metal compound (such as sodium or potassium) in a suitable solvent at a temperature in the range of -150 ° C to 300 ° C, preferably at a temperature in the range of 0 ° C to 100 ° C. Particularly effective anionic polymerization initiators are organolithium compounds having the formula: RLin wherein R is an aliphatic, cycloaliphatic, aromatic or aromatic hydrocarbon radical substituted with alkyl, having 1 to 20 carbon atoms, and n is an integer from 1 to 4. > * _ * Conjugated diolefins which can be anionically polymerized include those conjugated diolefins containing from 4 to 24 carbon atoms such as 1,3-butadiene, isoprene, piperylene, methylpentadiene, phenyl-butadiene, 3,4-dimethyl-1, 3- hexadiene, 4, 5-diethyl-l, 3-octadiene and the like. Isoprene and butadiene are preferred conjugated diene monomers for use in the present invention, because of their low cost and easy availability. Alkenyl (vinyl) aromatic hydrocarbons which may be copolymerized include vinyl-aryl compounds such as styrene, various alkyl substituted styrenes, substituted alkyloxy, vinylnaphthalene styrenes, alkyl substituted naphthalenes, and the like.

The monohydroxylated polydienes can be synthesized by anionic polymerization of diene hydrocarbons conjugated with lithium initiators. This process is well known and is described in U.S. Patent Nos. 4,039,593 and Re. 27,145 the disclosures of which are incorporated by reference herein. Polymerization begins with a monolithium initiator which builds a growing polymer backbone at each lithium site. The typical monolithic polymer growth structures containing conjugated diene hydrocarbons are: X-A-B-Li X-A-B-A-Li wherein B represents the polymerized units of a conjugated diene hydrocarbon such as butadiene, A represents the polymerized units of another conjugated diene such as isoprene, and A or B may contain, one or more vinyl aromatic compounds such as styrene, and X is the residue of a monolithium initiator such as sec-butyl lithium. The hydroxyl groups can be added by terminal plating of the polymerization with oxiranes such as ethylene oxide, followed by the termination with methanol. The monohydroxy-diene polymers can also be made using a monolithium initiator which contains a hydroxyl group which has been blocked as the silyl ether. A suitable initiator is the hydroxypropyllithium in which the hydroxyl group is blocked such as tert-butyl-dim, ethylsilyl ether. This mono-lithium initiator can be used to polymerize isoprene or butadiene in hydrocarbon or polar solvent. The growing polymer is then terminated with methanol. The silyl ether is then removed by acid catalyzed cleavage, in the presence of water, yielding the desired monohydroxy-polydiene polymer. When one of the conjugated dienes is 1,3-butadiene and this will be hydrogenated, the anionic polymerization of the conjugated diene hydrocarbons is typically controlled with structural modifiers such as diethyl ether or glime (1,2-diethoxyethane) to obtain the desired amount of 1.4 addition. As described in Re 27,145 which is incorporated by reference herein, the 1,2-addition level of a butadiene polymer or copolymer can greatly affect the elastomeric properties after the hydrogenation. The hydrogenated polymers show improved thermal stability and environmental resistance in the adhesive, sealant or final coating. The most preferred polymers are two-block polymers, which fall within the scope of formula (I) mentioned above. The full molecular weight of such diblocks can be in the range of from 1500 to 20,000, preferably from 3000 to 7,000. Any of the blocks in the diblock may contain some randomly polymerized vinyl aromatic hydrocarbon, as described above. For example, when I represents isoprene, B represents butadiene, S represents styrene, and a diagonal (/) represents a random copolymer block, the diblocks may have the following structures: IB-OH IB / SOH I / SB-OH II / B-OH or B / IB / S-OH BB / S-OH I-EB-OH I-EB / S-OH or IS / EB-OH I / S -EB-OH HO-IS / B HO-IS / EB wherein EB is hydrogenated butadiene, -EB / S-OH means that the hydroxyl source is attached to a block of styrene, and -S / EB-OH means that the hydroxyl source is attached to a block of hydrogenated butadiene. The latter case, -S / EB-OH, requires the encapsulation of the block of "random copolymer" S / EB with a miniblock EB, to compensate for the tendency to taper styrene before the encasement with ethylene oxide. These diblocks are advantageous, since they show lower viscosity and are easier to manufacture than the corresponding three-block polymers. It is preferred that the hydroxyl be attached to the butadiene block, because the epoxidation proceeds more favorably with isoprene, and there will be a separation between the functional groups on the polymer. However, the hydroxyl can also be attached to the isoprene block, if desired. This produces a molecule more like a surfactant, with less ability to carry cargo. The isoprene blocks can also be hydrogenated. Certain three-block epoxidized copolymers can also be suitably used. Such triblocks usually include a randomly copolymerized styrene or styrene block, to increase the glass transition temperature of the polymers, compatibility with the polar materials, strength, and viscosity at room temperature. These tribloques can have structures.

I-EB / S-EB-OH IB / SB-OH IS-EB-OH ISB-OH or II / SI-OH ISI-OH BSB-OH BB / SB-OH or IB / SI-OH I-EB / SI -OH OR IBS-OH I-EB-S-OH HO-I-EB-S The last group of polymers specified in the last line above, where the styrene block is external, are represented by the formula (II) (HO) x-A-B-S- (OH) and where A, B, S, x, and y are as defined above. The epoxidation of the base polymer can be effected by reaction with organic percents, which can be preformed or formed in itself. Suitable preformed percents include peracetic and perbenzoic acids. The formation in si tu can be achieved by the use of hydrogen peroxide and a low molecular weight fatty acid such as formic acid. These and other methods are described in detail in U.S. Patent Nos. 5,229,464 and 5,247,026, which are incorporated by reference herein. When the concentration of the alkenyl aromatic hydrocarbon monomer in the monohydroxylated epoxidized polymer is less than or equal to 5% by weight, the epoxy concentration can be in the range of 2 to 7 meq / g of polymer. When the concentration of the alkenyl aromatic hydrocarbon monomer is in the range of 5% to 20% by weight, the epoxide concentration can be in the range of 1 to 7 meq / g of polymer. When the concentration of monoalkenyl aromatic hydrocarbon is in the range of 20% to 60% by weight, the concentration of the epoxide can be in the range of 0.5 to 7 meq / g of polymer. If the epoxy levels are lower, it is anticipated that the components will be sufficiently compatible to stiffen the resin. Due to this decreased compatibility, at low epoxy levels, the mixing temperature will have to be undesirably high. At higher levels of epoxy, the components are expected to be too compatible and soluble to achieve the desired phase separation, after curing. This will also raise the viscosity and cost without any corresponding benefit. The presence of the hydroxyl group allows less epoxidation, which decreases the cost of the composition without adversely affecting its operation. The preferred levels of. Epoxy are 2.5 to 6 meq / g for less than 5% vinyl aromatic hydrocarbon, 2 to 6 for 5 to 20%, and 1 to 6 for 20 to 60%. If the epoxy levels are lower, then no clouding points of 85 ° C or less can be achieved without additional formulation ingredients. This is an indication of a compatible and uniform mixture, with uniform appearance and feel. Higher levels of epoxy are not preferred because they increase viscosity and cost without any appreciable benefit. It has been found that by combining <;? With the appropriate unsaturation, the epoxide level and the alkenyl aromatic monomer content, an epoxidized, monohydroxylated polydiene, which possesses appropriate compatibility with the epoxy resins, can be made to produce an improved balance of the properties. The presence of epoxidation and unsaturation is required in the monohydroxylated polymers of this invention. The diene monomers remain unsaturated before epoxidation in the preferred polymers. When the alkenyl aromatic monomers are present at concentrations of less than 5% by weight, the most preferred epoxide level is in the range of 3 to 5 meq / g of polymer. When the alkenyl aromatic monomers are incorporated at levels of 5% to 20% by weight in the over-unsaturated polydiene block copolymers, their compatibility with the epoxy resin is improved to such an extent that the lower levels of epoxidation will produce epoxy resins. modified with rubber, improved, and the most preferred range is 2.5 to 4.5. When the alkenyl aromatic monomers are present at concentrations of 20% to 60% by weight or greater, the most preferred epoxide level is in the range of 1.5 to 4 meq / g of polymer. It is believed that these ranges are optimal because they allow mixtures with a cloud point of not more than 70 β C (lower end of the range) and as low as 40 to 50 ° C (upper end of the range) to be made. It is believed that such compositions have the proper phase separation to achieve compositions with the best combination of properties, appearance and feel. The ability to form mixtures suitably compatible with epoxy resins is a primary feature of the molecules of the present invention. While the preferred epoxidized and monohydroxylated polymers are too unsaturated, the analogous hydrogenated polymers may also be suitable. In polymers of high epoxy and styrene content, it is anticipated that proper compatibility with epoxy resins will eventually result when all unsaturation is consumed by hydrogenation. These polymers offer the additional advantages of improved chemical resistance and improved thermo-oxidant oxygen, and stability to ozone and ultraviolet light. It has been found that monohydric polymers that have too low unsaturation or that are too low in epoxidation are highly incompatible with cycloaliphatic epoxy resins. These polymers can be used to produce excellent hardened cycloaliphatic epoxy resin compositions if another major ingredient is incorporated into the composition at a level of at least 20 weight percent. It is preferred that no more than about 60 weight percent of this component be added to the composition, because the curing agents such as the cationic photoinitiator, UVI-6974, become insoluble in the formulation. This third component is a vinyl ether. Vinyl ethers are particularly well suited for use in combination with cycloaliphatic epoxy resins, because vinyl ethers can also be cured via a cationic curing mechanism, which is frequently used to cure cycloaliphatic epoxy resin compositions. In the compatibility selection studies of the commercially available vinyl ethers, a vinyl ether remained as having particularly good compatibility with the epoxidized hydrogenated polymers. This vinyl ether was RAPI-CURE CHVE (RAPI-CURE is a trademark), cyclohexane-dimethanol-divinyl-ether, from ISP, Inc. Judging from the structures of the other commercially available vinyl ethers, it is likely that RAPI -CURE CHVE will also be the most effective for the compatibilization of the other monohydroxylated epoxidized polymers, and the cycloaliphatic resins of this invention. In yet another embodiment of this invention, a mixture of epoxidized and monohydroxylated polydiene polymer, used as a tenacity modifier, and a diluent with low molecular weight epoxy functional group, used as a viscosity reducer, is used as a modifier for cycloaliphatic epoxy resins. These diluents include epoxidized oils, such as epoxidized soybean oil and epoxidized castor oil, epoxidized oils of natural origin, such as vernonia oil, epoxidized olefins, such as vinyl cyclohexane monoxide, and glycidyl ether epoxides such as ether. of butyl-glycidyl, phenyl-glycidyl ether and the like. The appropriate proportion of epoxidized monohydroxylated polydiene polymer to the epoxidized diluent should be determined for each particular application. However, typically, the weight ratio of the monohydroxylated epoxidized polymer to the epoxidized diluent should be in the range of 100/1 to 1/1. Examples of useful flexibilizers are monofunctional aromatic epoxy resins, mono-, di-, and multi-functional aliphatic epoxy resins, and \ u > oils with epoxy functional group. Examples of monofunctional epoxy resins useful herein as flexibilizers are cresyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and the like. Other materials with epoxy functional group are also useful in the mixtures. Examples of oils with epoxy functional group include epoxidized linseed oil, epoxidized soybean oil, epoxidized castor oil, and vernonia oil. These additional materials with epoxy functional group are low weight oils They also tend to impart low viscosities to the formulations incorporating the compositions of the present invention. Epoxy resins modified with monohydroxylated epoxidized rubber, according to the invention, can be cured by a variety of means. Suitable epoxy curing agents include anionic initiators, cationic initiators, carboxyl functionalized polyesters, polyamides. amidoamines, polyamines, melaminoformaldehydes, phenol-for aldehydes, urea-formaldehydes, dicyandiamide, polyphenols, polysulfides, ketimines, novolacs, anhydrides, block isocyanates, anhydrides, and imidazoles. The composition will generally contain from 1 to 60, preferably from 30 to 60, percent by weight of curing agent, based on the epoxy resin composition. The anhydride curing agents are commonly used. Such anhydride curing agents can generally be described as any compound containing one or more anhydride functional groups. The most common anhydrides used have an aromatic, cycloaliphatic, or aliphatic structure. The curing agent can be selected from the group consisting of phthalic anhydride, substituted phthalic anhydrides, hydrophthalic anhydrides, substituted hydrophthalic anhydrides, succinic anhydride, substituted succinic anhydrides, halogenated anhydrides, multifunctional carboxylic acids, and polycarboxylic acids. Examples include phthalic anhydride (PA), tetrahydrophthalic anhydride (THPA), ethyl-nadic anhydride (NMA), hexahydrophthalic anhydride (HHPA), pyro elitic dianhydride (PMDA), methyltetrahydrophthalic anhydride (MTHPA), and dodecenylsuccinic anhydride (DSA) , and similar. In addition, multifunctional carboxylic acids will provide similar performance. The anhydride is combined with the modified epoxy resins, such that an appropriate molar ratio of anhydride is achieved. This proportion should be in the range of 0.8 / 1.0 to 1.2 / 1.0, to achieve the adequately complete formation of the epoxy network. It has now been found that the proportions that are most useful in achieving the improved properties are those that are as close to 1/1 as possible. Typically, anhydride cures are conducted at elevated temperatures, from 100 to 170 ° C for a period of 30 minutes to 6 hours, and are often referred to as "oven cures". Anhydride kiln cures can be accelerated by the use of a cure accelerator. Appropriate healing accelerators include trialkyl amines, hydroxyl-containing compounds and imidazoles. Benzyldimethylamine (BDMA), 2-ethyl-4-methylimidazole (EMI) and the amine complexes of BF3 have been found to work well in curing the mixtures of the present invention. Aliphatic amines such as diethylenetriamine (DETA) and triethylenetetraamine (TETA) are useful for the curing of the modified epoxy resins of the present invention. Aromatic amines such as diethyltoluenediamine and metaphenylenediamine (MPDA) are useful for the curing of the compositions of the present invention. The aromatic and aliphatic amines are generally used in a The equivalent ratio of 0.8 / 1.0 to 1.2 / 1.0 by weight, but it is preferred that the proportions are as close to 1/1 as possible.Polyamides such as the polyamide curing agent EPI-CURE 3140 (EPI-CURE is a trademark) supplied by Shell Chemical Company, are also useful in the curing of modified epoxy compositions. Usually, 30 to 130 parts per hundred parts of the polyamide resin are used. There is a wide range of reactivity of the various amines and curing agents of polyamide, and in this way cures can be carried out at room temperature and by baking by the appropriate choice of the curing agent and its proportion. The sulphonium salts of low nucleophilicity, 2-ethyl-a-methyl-imidazole, Benzyldimethylamine (BDMA), lanthanide (III) trifluoromethane-sufonates, lithium perchlorate, and the like, can also be used at catalytic levels (eg, 0.1 to 10 parts per hundred parts of resin) to increase the rate of cure of the amine and polyamide curing agents 5. Epoxy resins are known to be useful in such compositions. Another common method for curing the cycloaliphatic epoxide groups is via a catalytic homopolymerization lj * by ring opening, to generate ether bonds between the molecules. Typical catalysts are Lewis acids, such as boron trifluoride, and protic acids, including phosphoric acid, and sulfonic acids such as trifluoromethanesulfonic acid.

These acids will cure cycloaliphatic epoxy resins very quickly at room temperature. The amine blocked versions of these acids are also useful. Therefore, the resin and the catalyst must be used as a product of Two components, in which the two components are mixed immediately before the application, and must be applied before the mixture gels. These acids are also available in the salt form using volatile bases to block the reaction of epoxy curing. These blocked catalysts can be mixed with the epoxy resin, since no reaction occurs at room temperature, giving a single component product. After application, the formulation is baked, releasing the blocking agent to regenerate the acid, which initiates the cure of the epoxide groups. Another type of blocked catalytic curing agent, which is commercially available from Union Carbide as CYRACURE UVI-6974 (CYRACURE is a trademark), is an aryl-sulfonium salt which, when exposed to ultraviolet radiation, generates a cation that can start the healing of the epoxide groups. This cationic photoinitiator can be mixed with the cycloaliphatic epoxy resin in a single component product, which after application, can be exposed to ultraviolet radiation to initiate healing. The mixtures of the present invention can be used in any of the applications in which cycloaliphatic or aromatic epoxy resins are currently used. Typical applications are structural adhesives, coatings, composites and electrical encapsulators. The compositions of the present invention are useful in adhesives (including contact adhesives, laminating adhesives, mounting adhesives, and structural adhesives), in sealants, filling compounds, coatings such as top coatings for automotive inks (as replacements for resins such as turpentine, hydrocarbon and alkyd resin, as modifiers for the catidonic cure of UV filtration inks, lithographic and flexographic inks), and molded thermosetting parts. The blends of the present invention should be more flexible, have higher tenacity and have better resistance against thermal shocks when used in a structural adhesive, coating, compound or encapsulator, than in products using cycloaliphatic or aromatic epoxy resins. , alone. A wide variety of fillers may be used in the formulations within the present invention. Suitable fillers include calcium carbonate, clays, talcs, zinc oxide, titanium dioxide, silica and the like. The amount of fillers is usually in the range of 0 to 65% by weight of the formulation, depending on the type of filler used, and the application for which the formulation is intended. Preferred fillers are silica and titanium dioxide.

Stabilizers known in the art can also be incorporated into the composition. These can be for protection during the life of the article against, for example, oxygen, ozone and ultraviolet radiation. These may also be for stabilization against thermo-oxidative degradation during processing at elevated temperature. Antioxidants that interfere with the healing reaction should be avoided. ~ In the applications of structural compounds, the epoxy resin composition includes reinforcing fibers. Such fibers include glass fibers, graphite fibers, carbon fibers, silicon carbide fibers, aramid fibers, fibers of boron, alumina fibers, and the like. Other thermosetting resins which may optionally be included in the composition include, for example, polyurethane, polyureas, polyamides, brominated epoxides, phenoxy resins, polyesters, polyester-polyether copolymers, bismaleimides, polyimides, and mixtures and copolymers thereof. The compositions in accordance with the present invention can include other additives, such as extenders, plasticizers, pigments, coating agents, reinforcement, agents for flow control and fire retardants. The molecular objects of the linear Dolímeros or the linear assemblies unassembled of the polymers such as the arms of a block, of two blocks, of 5 three blosses, etc., of the Dolímeros in star form before the coupling, are conveniently measured by Gel Permeation Chromatosraphy (GPC), where the GPC system has been properly calibrated. For polymerized anionic tf linear polymers, the polymer is essentially monodisperse (the ratio of the weight average molecular weight / number average molecular weight is about unity), and is convenient and suitably descriptive to report "peak" molecular weight of the observed, narrow molecular weight distribution. Usually, the peak value is between the average number and the weight. The peak molecular weight is the molecular weight of the main species shown in the chromatograph. For polydisperse polymers the weight The molecular weight average must be calculated from the chromatograph and used. For the materials to be used in the GPC columns, styrene-divinyl-benzene gels or silica gels are commonly used and are excellent materials. He Tetrahydrofuran is an excellent solvent for polymers of the type described herein. A refractive index detector can be used. The measurement of the absolute molecular weight of a polymer is not as direct or so easy to be made using GPC. A good method to be used for the determination of absolute molecular weight is to measure the weight average molecular weight by light scattering techniques. The mixture is dissolved in an appropriate solvent at a concentration of less than 1.0 gram of sample per 100 milliliters of solvent, and filtered using a syringe and porous membrane filters of less than 0.5 micron pore size, directly into the dispersing cell of light. The light scattering measurements are performed as a function of the scattering angle, the concentration of the polymer and the size of the polymer using standard procedures. The differential refractive index (DRI) of the sample is measured at the same wavelength and in the same solvent used for light scattering. The following references in this regard are of interest. 1. Modern Size-Exclusion Liquid Chromatography, M. Yau, J. J. Kirkland, D. D. Bly, John Wiley and Sons, New York, New York, 1979. 2. Light Scattering From Polymer Solutions, M: B: Huglin, ed., Academic Press, New York, New York, 1972. 3. .K. Kai and A. J. Havlik, Applied Optics, 12, 541 (1973). 5 4. M. L. McConnell, American Laboratory, 63, May, 1978.

If desired, these block copolymers can be partially hydrogenated. The hydrogenation is Can you perform selectively as described in. the reissue of U.S. Patent No. 27,145 which is incorporated by reference herein. The hydrogenation of these polymers and copolymers can be carried out by a variety of well processes , including hydrogenation in the presence of catalysts such as Raney Nickel, noble metals such as platinum and the like, soluble transition metal catalysts, and titanium catalysts, as described in US Patent No. 5,039,755, which is also incorporated by reference in the presenté. The polymers will have different diene blocks, and these diene blocks can be selectively hydrogenated as described in U.S. Patent No. 5,229,464 which is also incorporated by reference herein. The partial unsaturation is preferably such that 0.5 to 7 meq / g of aliphatic double bonds remain for subsequent epoxidation. The hardened epoxy resin compositions of this invention can be used in a wide variety of applications. These are useful in adhesives, including contact adhesives, laminated adhesives, and assembly adhesives, but are especially useful in structural adhesives where these can be combined with a wide range of curing agents to form excellent products that adhere to metals, plastics, wood, glass and other substrates. These also have special utility in coatings (especially aprestadores, upper coatings for automobile epoxy prospectors for metal, coatings of spiral of polyester, alquídicos coatings of maintenance, etc.), where these can combine with pigments and agents of curing to form excellent products. Other applications for these compositions include electrical applications such as rollers, encapsulators, filling compounds, welding masking compounds, and laminate and construction applications such as floor covering, in civil engineering, concrete repair and consolidation, secondary containment of tancaje, grouts, sealants, polymeric concrete, structural compounds, tools, etc.

Example 1 Various performance properties of the cured, aromatic epoxy resin compositions of the present invention are important. The _ < Traction properties such as strength, elongation and Young's modulus are measured according to ASTM D-638. Bending properties such as bending modulus, stress and elongation at break are measured according to ASTM D-790. Tenacity tensile fracture, as characterized by the stress intensity factor (K? C) for the propagation of the crack, is measured according to ASTM E-399-83. Using the value of K? C measured thus, the fracture energy (Gic) was calculated for the conditions of elongation in plane, used. Adhesive properties such as blade shear strength are measured according to ASTM D-1002. The vitreous transition temperature (Tg) is measured using dynamic mechanical torsion bar analysis. Table I below describes the composition of the epoxidized polydiene polymers used in this Example. The epoxidized, monohydroxylated and non-hydroxylated polydienes are compared.

TABLE I Composition of Epoxidized Polymers * S - Yes, N - No In the column of the polymeric base architecture of Table I, B represents the poly (1,3-butadiene) blocks, I represents the polyisoprene blocks, and OH represents the monohydroxyl functional group. The homopolymer blocks are separated by a hyphen. The cloud points of the mixtures of the exemplary polymers in the EPON 828 resin (EPON is a trademark) at a ratio of 1/9 by weight are shown in Table I. A clear and significant advantage is shown for the monohydroxylated polymer epoxidized Very similar cloud points are achieved for the two polymers, but the polymer in the present invention achieved that cloud point only with 3.4 meq / g epoxy, 1.4 meq / g lower than the comparative non-hydroxylated polymer. The epoxy resin compositions were prepared as follows. 11 parts of monohydroxylated epoxidized polymer A, or 11 parts of the comparative monohydroxy polymer, both having the base structure I-B, were added to 100 parts of the EPON resin 828, a glycidyl ether of bisphenol-A. 33 parts of EPI-CURE 3140 (a polyamide curing agent) per hundred parts of EPON 828 resin plus the epoxidized polymer were added to the mixture and manually stirred. A small amount was added (less than 1 part per hundred parts of EPON 828 resin plus epoxidized polymer) of PC-1344 / epoxy solution with monofunctional glycidyl, to help defoaming the mixture. The mixture was degassed under vacuum and centrifuged. The mixture was emptied between glass plates to make 3.175 mm plates. (1/8 inch) which were cured at room temperature for 7 days before the test. The mechanical properties of the resultant rubber modified epoxy resins are listed in Table II which provides a comparison of these mixtures and the cured epoxy resin without added epoxidized polymer. The incorporation of the Polymer and the comparative polymer leads to increases in fracture energy (G? C) of 192% and 92%, respectively, while maintaining good tensile and bending properties. These results demonstrate that these epoxidized polymers are effective in achieving a superior balance of properties in epoxy resins, cured with polyamides, and because the monohydroxylated epoxy polymer gives superior results to those of the non-hydroxylated epoxidized polymer, although the latter has a higher epoxy content.

TABLE II Example 2 An important application of these cycloaliphatic epoxy resin compositions, modified with epoxidized rubber, is in coatings, especially crosslinked coatings via a UV-initiated cationic cure reaction. Based on the data in other resin systems, it is believed that an epoxidized monohydroxylated polydiene polymer could be more compatible with cycloaliphatic epoxy resins than epoxidized polydiene polymers, without hydroxyl group at the same epoxidation level. However, there are no data available that describe the compatible region for these polymers in cycloaliphatic epoxy resins. Therefore, the structures that some hypothetical polymers could have, in order to demonstrate this invention, have been predicted. The formulation that could have been used for these hypothetical experiments, could comprise 78.9% by weight of the cycloaliphatic epoxy resin, CYRACURE UVR-6110 (CYRACURE is a trademark), 3,4-epoxycyclohexyl-methyl-3, -epoxycyclohexane carboxylate of Union Carbide, 20% of epoxidized rubber, 1% of cationic photoinitiator, CYRACURE UVI-6974, mixed salts of triarylsulfonium hexafluoroantimonate from Union Carbide, and 0.1% of a wetting agent, FLUORAD FC-430 (FLUORAD is a trademark) , a non-anionic fluorochemical surfactant of 5 3M, which could be used to reduce the surface tension of the coating, and improve its ability to wet the aluminum substrate on which it could be coated. The components could be mixed manually at 100 ° C. The mixtures could be first verified for phase stability by visually inspecting them after they have been left to rest in a bottle overnight. If they were stable phase, they could be heated to 70 ° C and applied to aluminum substrates with a # 40 wire rod to a dry film thickness of approximately 2.54 x 10"2 mm.The coatings could be cured by exposure to ultraviolet radiation from a medium pressure Hg lamp, at a linear speed of 9.14. m / min (30 feet per minute). The coatings could then be baked for 10 minutes at 120 ° C to complete the cure. Its properties could then be evaluated. The hypothetical polymers within this invention, which must make the coatings are described in Table III: TABLE III Composition of Epoxidized Polymers.

In the architecture column of the base polymer of Table I, B represents polybutadiene, I represents polyisoprene, S represents polystyrene, and EB represents hydrogenated polybutadiene, respectively. The homopolymer blocks are separated by a hyphen. The blocks of random copolymers are represented by S / B for randomly copolymerized styrene, and butadiene and S / EB for a block of hydrogenated S / B. In all polymers the microstructure of the polybutadiene is 45% 1.2 addition. The results would show that these six polymers could have good compatibility with cycloaliphatic epoxy and all six sd be effective in improving the flexibility of the coatings. The results would show in general that the hydrogenated polymers (D, E and F) require a higher level of epoxidation, in order to gain compatibility with the cycloaliphatic epoxy resin than with the non-hydrogenated polymers (A, B and C). Polymers that do not contain styrene (A and D) also require a higher level of epoxidation than polymers containing styrene. { B, C, E and F) in order to gain compatibility with the cycloaliphatic epoxy resin. In order to determine that the low levels of epoxidation are insufficient to obtain compatibility with the cycloaliphatic epoxy resin, various polymers were incorporated into the following formulation, in an attempt to make modified cycloaliphatic epoxy resin compositions, for crosslinked coatings via a reaction of cationic healing initiated by UV.

Component% by weight CYRACURE UVR-6110 76.7 Polymer 20.0 CYRACURE UVI-6974 3.2 FLUORAD FC-430 0.1 The following epoxidized monohydroxylated polymers were used.

Content Architecture Weight of Molecular Polymer, Styrene, epoxy content Base Polymer Miles% by weight meq / gm 1 IS / EB-I 1-2.5 / 1.5-1 40 1.2 2 IS / EB-OH 2-2.5 / 1.5 40 0 3 IS / EB-OH 2-2.5 / 1.5 40 1.5 4 I-EB-OH 2-4 0 0 5 I-EB-OH 2-4 0 1.5 A master batch of resin, photoinitiator, and surfactant was prepared. The polymers were added to this masterbatch, and the mixtures were heated to 80 ° C and stirred manually. The mixtures were then used at room temperature and allowed to stand to see if they could be separated in phases. The results showed that the five mixtures were separated in phases, indicating that none of the five polymers was compatible with the cycloaliphatic epoxide.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following:

Claims (13)

1. A hardened epoxy resin composition, characterized in that it comprises: a) a curable aromatic or cycloaliphatic epoxy resin, b) a monohydroxylated epoxidized polydiene polymer, which comprises at least two polymerizable ethylenically unsaturated hydrocarbon monomers, wherein at least one it is a diene monomer which produces unsaturation suitable for the epoxidation, and wherein the polymer contains from 0.5 to 7 milliequivalents (meq) of epoxy per gram of polymer, and c) a curing agent.

2. The composition according to claim 1, characterized in that the epoxidized monohydroxylated polydiene polymer has the structural formula (HO) x-A-S? -B- (OH) and O (HO)? - A-B-S- (OH) and wherein A and B are polymeric blocks which can be homopolymer blocks of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomers, or copolymer blocks of diolefin monomers and monoalkenyl aromatic hydrocarbon monomers, S is a vinyl hydrocarbon block aromatic, x and y are 0 or 1, and any of x and y must be 1, but only one at a time can be 1, and z is 0 or 1.

3. The composition according to claim 2, characterized in that the A blocks have a molecular weight of 100 to 6000, and the B blocks have a molecular weight of 1000 to 15,000.

4. The composition according to claim 2, characterized in that the conjugated diolefin in block A is isoprene, and the conjugated diolefin in block B is butadiene.

5. The composition according to any of claims 1 to 4, characterized in that the curing agent is selected from the group consisting of phthalic anhydride, substituted phthalic anhydrides, hydrophthalic anhydrides, substituted hydrophthalic anhydrides, succinic anhydrides, substituted succinic anhydrides, halogenated anhydrides. , multifunctional carboxylic acids, and polycarboxylic acids.

6. The composition according to any of claims 1 to 5, characterized in that the aromatic epoxy resin is a glycidyl ether prepared by the reaction of epichlorohydrin with an aromatic compound containing at least one hydroxyl group, carried out under reaction conditions alkaline

7. The composition according to any of claims 2 to 6, characterized in that the concentration of the epoxidized polymer is in the range of 1 to 50% by weight of the composition.

8. The composition according to any of claims 1 to 7, characterized in that the amount of vinyl aromatic hydrocarbon in the polymer is 5% by weight or less, and the epoxy content is from 2 to 7 meq / g of polymer.

9. The composition according to any of claims 1 to 7, characterized in that the amount of vinyl aromatic hydrocarbon in the polymer is from 5 to 20% by weight, and the epoxy content is from 1 to 7 meq / g of polymer .

10. The composition according to any of claims 1 to 7, characterized in that the amount of vinyl aromatic hydrocarbon in the polymer is from 20 to 60% by weight, and the epoxy content is from 0.5 to 7 meq / g of polymer .

11. The composition according to any of claims 1 to 8, characterized in that the epoxy resin is a cycloaliphatic epoxy resin, and the polymer contains 1.5 to 6.0 milliequivalents of epoxy per gram of polymer.

12. A structural adhesive composition, characterized in that it comprises the composition according to any of claims 1 to 11.

13. A coating composition, characterized in that it comprises the composition according to any of claims 1 to 11.