IE42663B1 - Poly(bis(substituted amino alkyl)phenols) - Google Patents

Abstract

1489733 Poly - [bis - (substituted aminomethyl)phenols]; hardening agents for epoxy resins AMERICAN VELODUR METAL Inc 24 March 1976 [10 April 1975] 11876/76 Heading C2C [Also in Division C3] The invention comprises compounds of the general Formula I wherein n has a value of at least two which may be prepared by reaction of phenol, formaldehyde, and triethylamine followed by reaction of the product with 3,5,5-trimethyl-3- aminomethylcyclohexylamine, the reactants being employed in stoichiometric amounts to give products having a desired value for n. The compounds of the invention have application as hardening agents for epoxy resins having at least one 1,2-epoxide group.

Description

The invention relates to new compounds suitable for hardening epoxy resins having at least one 1,2-epoxide group.

Novel hardening agents are set forth that are capable of hardening epoxy resins at or below room temperatures (as low as about 5°C) with5 out having to supply an external source of heat to effect the hardening of the resin.

This invention also relates to compositions and methods of using said compositions and hardening agents to form a resinous coating on a substrate that will protect the same against the deleterious action of a wide variety of materials including, jet fuels, kerosene, heating oils, acids and solvents. The methods and compositions disclosed are particularly useful for coating jet fuel tanks, heating oil tanks and other containers of highly flammable liquids, due to the absence of volatile solvents in the coating compositions.

The present invention provides, in one aspect, compounds suitable for use in hardening epoxy resins and having the formula: wherein n has a value of at least 2. the preferred compounds have a value of n of from 2 to 5. Best results are generally achieved when n is 2.

The novel compounds of this invention are useful for the hardening of epoxy resins or polyepoxides which comprise those organic materials possessing at least one vic-epoxy group, i.e., - 2 426 63 The epoxy compounds may contain saturated or unsaturated aliphatic cycloaliphatic or aromatic hydrocarbon groups or heterocyclic groups and may contain substituents such as halogen atoms, hydroxyl groups or ether radicals. They may be monomeric or polymeric.

Usually, such epoxide resins comprise a polyether derivative of a polyhydrie organic compound, said derivative containing 1,2-epoxy groups and being selected from polyhydrie alcohols and phenols containing at least two phenolic hydroxy groups.

Among the polyhydrie phenols which may be used in preparing such glycidyl polyethers are the mono-nuclear phenols such as resorcinol, catechol and hydroquinone, and the polynuclear phenols such as bis(4hydroxyphenyl)-2,2-propane, 4,4'-di hydroxybenzophenone, bi s (4-hydroxyphenyl)-!,1-ethane, bis(4 - hydroxyphenyl) - 1,1 - isobutane, bis(4hydroxyphenyl) - 2,2 - butane, bis(4-hydroxy-2-methylphenyl)-2,2-propane, bis - (4 - hydroxy - 2 - tertiary butyl phenyl) - 2,2 - propane, bis(4 - hydroxy - 2,5 - dichlorophenyl) - 2,2 - propane, 4,4' - dihydroxybis - phenyl - 4,4' - dihydroxypentachlorobisphenyl, bis(2 - hydroxynaphthyl )methane, 1,5 - dihydroxynaphthalene, phloroglucinol, 1,4dihydroxynaphthalene and l,4-bis(4-hydroxyphenyl)cyclohexane, as well as other complex polyhydrie phenols, such as pyragallol, phloroglucinol and novalac resins from the condensation of a phenol with an aldehyde in the presence of an acidic condensation catalyst. For the nature and preparation of novalac resins, see the bool by T. S. Carswell, Phenylplast, 1947. page 29, et. seq.

There can also be used 1,2-epoxy containing ethers of aliphatic polyhydrie alcohols, such as polyglycidyl ethers thereof, as for example, the diglycidyl ethers of ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol, diethylene glycol, 4,4'-dihydroxydicyclohexy! triethylene glycol, glycerol and dipropylene glycol as well as ethers containing more than two glycidyl groups such as the glycidyl poly-ethers, - 3 436G3 glycerol, mannitol, sorbitol, polyalkyl alcohol and polyvinyl alcohol. These epoxide resins, or glycidyl polyethers as they are frequently called may be prepared by reacting predetermined amounts of at least one polyhydric compound and one epihalohydrin in an alkaline medium.

While it is preferred to use epichlorohydrin as the epihalohydrin in the preparation of the epoxide starting materials, other epihalohydrins such as epibromohydrin may be used advantageously.

In the preparation of the epoxide resins, aqueous alkali is employed to combine with the halogen of the epihalohydrin, The amount of alkali employed should be substantially equivalent to the amount of halogen present and, preferably, should be employed in an amount somewhat in excess thereof. Aqueous mixtures of alkali metal hydroxides, such as potassium hydroxide and lithium hydroxide may be employed; although for economic reasons, sodium hydroxide is obviously preferred.

The product of the above-described reaction instead of being a single simple compound is generally a complex mixture of glycidyl polyethers, but the principal product may be represented by the formula: A —CH2-(O-R-O-CH2-CHOH-CH2)n-O-R-O-CH2-CH—CH2 where n is 0 or an integer, preferably having a maximum value of 10, and R represents a divalent hydrocarbon radical of a polyhydric compound, and preferably a dihydric phenol. While for any single molecule n is an integer, though the fact that the obtained polyether is a mixture of compounds, causes the determined value for n, e.g., from molecular weight measurements to be an average which is not necessarily a whole number.

Preferred polyethers for use with the hardening agents of this invention are prepared from bis(4-hydroxyphenyl)-2,2-propane and contain a chain of alternating glyceryl and 2,2-bis(phenylene)propane radicals, separated by intervening ethereal oxygen atoms and have a 1,2-epoxy equivalency between 1 and 2, and epoxide equivalent weight of about 170 to - 4 about 250. A particularly suitable material for use in the invention is a normally liquid glycidyl polyether of bisphenol-A having an epoxide equivalent weight of about 175 to 200 and a 1,2-epoxy equivalency of about 1.8 to about 1.95.

The term epoxy equivalency as employed in this specification refers to the number of epoxy groups contained in the average molecule of the desired material. The epoxy equivalency is obtained by dividing the average molecular weight of the polyepoxide by the so-called epoxide equivalent weight. The epoxide equivalent weight is determined by heating one gram sample of the polyepoxide with an excess of pyridinium chloride dissolved in pyridine at the boiling point for twenty minutes.

The excess pyridinium chloride is then back-titrated with 0.1 N sodium hydroxide to phenol-phthalein end point. The epoxide value is calculated by considering 1 HCl as an equivalent of one epoxide. This method is used to obtain all epoxide values reported herein.

The novel compounds of this invention are used in an amount sufficient to harden the epoxy resin to an insoluble and infusible polymer. Generally, the amount of hardening agent used should be at least a 5? stoichiometric excess, and as used herein, stoichiometric amount refers to that amount needed to furnish one amino hydrogen for every epoxy group to be reacted. Particularly superior results are obtained when the hardening agent is employed in from 5 to 50% stoichiometric excess.

The preferred hardening additive wherein n has a value of 2, may be prepared by stirring 6 mols phenol, 3 mols formaldehyde (in the form of a 36% formalin solution) and 0.5 weight percent of triethylamine, for about 2 hours. Nine mols of 3,5,5-trimethyl-3-aminomethyl cyclohexylamine are then added to the solution and the resultant solution is heated for about 1 hour at 100°C. The water produced during the reaction is removed by distillation.

The hardening agent produced is light yellow in color and is highly - 5 43663 reactive v/ith epoxy resin. Thus, compounds normally used to accelerate the hardening action are not required in the practice of this invention due to the high reactivity of the hardening agents of this invention with epoxy resin.

In another aspect, the invention provides a hardenable epoxy resin composition comprising a compound having the formula I above together with a liquid epoxy resin having at least one 1,2-epoxide group.

In a further aspect, the invention provides a package comprising in separate components an epoxy resin having at least one 1,2-epoxide group on the one hand and a compound having the formula I on the other hand.

A preferred composition of the present invention has a fluid consistency and is capable of being applied as a uniform coating that hardens to form a smooth, tough and adherent coating, possessing good mechanical and chemical resistant properties. The compositions and packages of the present invention preferably include: (A) a liquid epoxy resin having terminable epoxy groups and an epoxy equivalent from 185 to 210 and a viscosity of 900 cps or less at 25°C; (B) a filler material in an amount between 20 and 50 weight percent of said epoxy resin; (C) an effective amount of a dispersing agent for said filler material; and (0) the novel hardening additive of this invention wherein n has 25 a value of at least 2, and preferably between 2 and 5.

A process using the composition of the present invention for coating a substrate comprises applying to the surface the above-identified composition and then allowing the coating to cure without the application of any heat.

The liquid epoxy resins used in this embodiment of the invention - 6 42663 are the reaction products of epichlorohydrin and diphenylol propane and having the following formula: These resins have a viscosity below 900 cps at 25°C and preferably between 700 to 800 cps at 25°C. The preferred value of n', in the above structural formula, is 0.2, whereby said resin has an approximate molecular weight of 380 although the value of n' can vary between 0 and . It is understood that when the above epoxy resin is produced, it is a mixture of compounds that causes the determined value for n' to be an average which is not necessarily zero or a whole number such as 1.

A particularly preferred resin exhibiting the above properties is Epon 828 manufactured by Shell Chemical Company. Other commercial liquid epoxy resins which are equivalent to the Epon 828 for the purpose of this invention, are DER-331. sold by Dow Corning Corporation and Ciba Resin 502, sold by Ciba, Ltd.

The term epoxy equivalent refers to the mean molecular weight of the epoxy resin divided by the number of epoxy radicals per molecule, or in any case, the number of grams of epoxy resin equivalent to one epoxy group or one gram equivalent of epoxide.

The amount of the novel hardener useful in the practice of this embodiment of the invention is an effective amount sufficient for causing the epoxy resin to harden. Generally, the amount of hardener used is between 35 and 40 percent, and preferably 35 percent by weight, based on the total weight of the liquid epoxy resin described above.

It is usually desirable to add the hardening agent to the composition just prior to use, particularly because the hardening agent renders the composition readily curable at or near ordinary room temperature as well as under lower temperatures. - 7 42663 The compositions of this invention preferably contain from 20 to 50 percent, and preferably 33 percent by weight of the desired epoxy resin, and at least one filler which is inert with respect to the remaining ingredients of the composition and which have a particle size up to 50 microns. Generally, the size of the filler particles range between and 50 microns.

Examples of suitable inert fillers include sand, crushed shells, rocks, aluminum powder, copper powder, quartz powder, titanium dioxide, asbestos, silica, calcium carbonate, graphite, black iron oxide, silicon dioxide, diatomaceous earth, alumino-silicates, silicone, carbide, boron carbide, vermiculite, talc and mica. Best results, in terms of corrosion inhibition are obtained with stainless steel flakes, steel powder, titaniferrous magnetite oxide or mixtures thereof.

The compositions of the invention also preferably contain agents to promote the adequate and uniform distribution of filler particles in the resin. Best results are achieved when an effective amount of fumed silica is employed. Generally, between 5 and 20 percent, and preferably 10 percent by weight of the liquid epoxy resin is employed. The fumed silica not only prevents the settlement of the filler material in the composition, but also enhances the over-all anticorrosion properties of the coating composition.

As optional ingredients for the practice of this invention, it is desired to include silicic acid in an amount of from 1 to 7 percent by weight, and preferably 3 percent by weight of the epoxy resin. The silicic acid promotes the adhesion of the coating composition to wet, greasy or oily surfaces. Another optional ingredient is silicon oil which is employed in an amount of between 1 and 2 ounces per 120 pounds of the total base composition. The silicon oil facilitates pigment distribution when pigments are utilized in combination with the composition of this invention. The silicon oil also decreases the surface tension - 8 /13 6 6 3 of the composition and facilitates the spreading of the composition on a particular substrate.

Compositions of this invention can also contain sufficient amounts of aluminum hydroxide as a flame retardant for the composition. It is understood that other equivalent compounds can be used as a substitute for aluminum hydroxide although this compound is the preferred flame retardant additive for the invention. Generally, aluminum hydroxide is present in an amount of up to 5 percent by weight of the composition.

In general, the separate components of the composition can be admixed in any desired order and, if desired, combinations of two or more components may be prepared initially with the remaining components being added subsequently. However, as noted hereinbefore, it is usually desired to add the hardening agent just prior to use since the hardening agent renders the composition readily curable at or near room temperature with no external source of heat being required for hardening purposes.

When the above-described compositions are applied to a given substrate, the coatings are found to exhibit highly satisfactory chemical resistance to jet fuels, gasoline, heating oils and solvents, as well as high compression strength, a low rate of shrinkage, good heat resistance, satisfactory thermal coefficient of expansion and adhesive properties.

The compositions of this invention may be employed for the coating and/or repair of any type of surface. These surfaces include, for example, wood, cement, metal and glass. The compositions are particularly suited for use in treating metal surfaces, such as, for example, copper, aluminum, brass, steel, and iron surfaces. The surfaces may be in any type of structure, such as for example, pipes, piling, reaction vessels, structural members of oil well drilling platforms, containers for jet fuels, heating oils and solvents, well jackets, heat exchange tubes and molds. - 9 42663 When the coating compositions of this invention are applied to a particular substrate to impart chemical resistance, the coating compositions are applied in an amount sufficient toprovide the chemical resistan desired. More specifically, the coatings are applied in an amount sufficient to provide a film or coating of at least 0.3 millimeters thick The coatings of the compositions can be applied to substrates by conventional techniques known in the art including spreading, spraying or dipping, and thereafter permitting the composition to cure at or below room temperature to form a hard durable coating having satisfactory chemical resistance and being attractive in appearance.

Claims (8)

1. Compounds suitable for use in hardening epoxy resins and having the formula 5 wherein n has a value of at least 2,

2. A compound of Claim 1, wherein n has a value from 2 to 5.

3. A compound of Claim 1, wherein n has a value of 2.

4. A compound as claimed in Claim 1 substantially as described herein. 10

5. A hardenable epoxy resin composition comprising a compound as claimed in any preceding claim together with a liquid epoxy resin having at least one 1,2-epoxide group.

6. A package comprising in separate components a liquid epoxy resin having at least one 1,2-epoxide group on the one hand and a compound as 15 claimed in any of claims 1 to 4 on the other hand.

7. A composition as claimed in claim 5 wherein the liquid epoxy resin has an epoxy equivalent from 185 to 210, and a viscosity at 25°C of 900 cps. or less, which further comprises a filler material in an amount between 20 and 50 wt.% of said epoxy resin and an effective amount 20 of a dispersing agent for the filler material.

8. A package as claimed in claim 6 wherein the liquid epoxy resin has an epoxy equivalent from 185 to 210, and a viscosity at 25°C of 900 cps. or less.