WO2001016204A1

WO2001016204A1 - Process for upstaging epoxy resins

Info

Publication number: WO2001016204A1
Application number: PCT/EP2000/008404
Authority: WO
Inventors: Simon Ming-Kung Li
Original assignee: Shell Internationale Research Maatschappij BV; Resolution Research Nederland BV
Current assignee: Shell Internationale Research Maatschappij BV; Resolution Research Nederland BV
Priority date: 1999-08-30
Filing date: 2000-08-25
Publication date: 2001-03-08
Anticipated expiration: 2002-02-28
Also published as: AU7903900A; JP2001064353A

Abstract

The present invention comprises a continuous process for upstaging epoxy resins to produce resins with higher molecular weight, which process comprises: (a) continuously passing a solution of a compound having active hydrogens or reactive functional groups capable of reacting with a liquid epoxy resin, a liquid epoxy resin, an inert solvent, and a catalyst through a series of sequentially staged reaction chambers; (b) the equivalency ratios of said compound having active protons or reactive functional groups to liquid epoxy resin introduced into the reaction chambers being from about 3.3:1 up to 0.5:1; the temperature in the reaction chambers is in the range of 49 °C-216 °C (120 °F-420 °F), and increases from chamber to chamber, and maintaining the pressure at normal or above normal in said reaction chambers, and stirring the materials during the reaction thereof with a mixing means; and (d) discharging the higher molecular weight product epoxide resin or hydroxy-terminated polyether of the final stage reaction chamber.

Description

PROCESS FOR UPSTAGING EPOXY RESINS

The present invention relates to an improved process for upstaging liquid epoxy resins to produce higher molecular weight resinous polyepoxides or hydroxy- terminated polyethers. More specifically, this invention relates to processes for the continuous production of epoxy resins or hydroxy-terminated polyethers in solvents. This invention also relates to the continuous production of epoxy resins or hydroxy-terminated polyethers having uniform consistency. The epoxy resin and hydroxy-terminated polyether products of the instant invention exhibits more uniformity and consistency.

This invention also relates to improvements in the production of thermosetting resinous polyepoxides, including processes and the products resulting therefrom. The present invention also relates to the continuous production of higher molecular weight epoxy resins or hydroxy-terminated polyethers using sequentially staged reactors .

Since their discovery, thermosetting resinous polyepoxides, i.e., epoxy resins, hydroxy-terminated polyethers or phenoxy-terminated resins have in industries and scientific disciplines found application in many forms, principally as surface-coating materials combining toughness, flexibility, adhesion and chemical resistance to a nearly unparalleled degree.

The epoxy resins are fundamentally polyethers, but retain their epoxy nomenclature on the basis of their starting material and the presence of epoxide groups in the polymer before crosslinking or curing. The most common types of resinous polyepoxides are produced by reaction of monomeric epoxy compounds, primarily epichlorohydrin, with dihydric phenols, such as bisphenol-A (BPA) , to give diglycidyl ethers. Depending upon molecular weight, the resinous polyepoxide may vary from a viscous liquid to a high melting solid. The higher molecular weight resinous polyepoxides or hydroxy-terminated polyethers can be made by a process known as "upstaging", "upgrading", fusion or "advancement". In such an upstaging or advancement process, an initial liquid resinous polyepoxide is reacted with a dihydric phenol in the presence of a catalyst until enough of the dihydric phenol is incorporated into the epoxy polymer chain to increase molecular weight to the desired level.

Such upstaging processes have in the past been conducted both on a batch basis and on a continuous basis. See, for example, U.S. Patent Nos . 3,547,881, 3,919,169 and 4,612,156. In such known batch and continuous upstaging processes, the dihydric phenols and liquid polyepoxide together with a catalyst are admixed or otherwise contacted at a relatively low temperature and then heated up to the reaction temperature and held at reaction temperature for a time sufficient to produce the resinous polyepoxide or hydroxy-terminated polyether of higher molecular weight. In such known batch upstaging processes, however, cycle times are typically relatively lengthy. For example, batch production involving bisphenol-A and a liquid polyepoxide consisting essentially of the diglycidyl ether of bisphenol-A can take from 8 to 12 hours of cycle time. This includes the charging of raw materials, reaction, and discharging and solidification/packaging of the product. Moreover, batch processes are generally labor intensive and equipment intensive. When a solid resin product is produced, long batch cycle time can lead to resin products with wider molecular weight distributions as well as higher softening points (Tg) and viscosities.

The resin products are typically prepared by fusing the lower molecular weight epoxy resin (like EPON Resin 828, EPON is a trademark) with the corresponding component such as bisphenol-A or tetrabromobisphenol-A (TBBPA) in a batch reaction system by base catalysis using a catalyst like triphenyl phosphine (TPP) or triphenyl phosphonium ethyl iodide (TPPEI). However, in commercial production when large quantities of the product are made in a single batch, it takes a long time to discharge ("dump") the product out of the reaction vessel. Hence the product does not always have uniform consistency in a given batch due to different residence time in the reaction vessel. In addition, there are usually batch-to-batch differences and also batch operations are usually labor and capital-intensive.

On the other hand, continuous reaction systems have been employed to upstage epoxy resins, i.e., via a static mixer reactor as shown in U.S. Patent No. 3,919,169; or by twin-screw extruder fusion as disclosed in U.S. Patent No. 4,612,156. The process proposed in U.S. Patent No. 3,919,169 appears to suffer from the formation of gel, perhaps due to the broad residence time distribution resulting from moving the high molecular weight and high viscosity resin products through the static-mixer reactor. In the case of the process proposed in U.S. Patent No. 4,612,156, residence time distribution is narrow. However, the residence time in extruders is short by design. Consequently, significantly higher amounts of catalyst must be used to compensate for the short reaction/residence time. Also, the extruder-reactor is an expensive piece of equipment. Neither of the above two patents discloses the use of a solvent in the reaction system. Figure 1 is a schematic diagram of the reactor system used to upstage epoxy resins or hydroxy-terminated polyethers using the process of the present invention.

Accordingly, a primary object of the present invention is to provide improvements in the production of a higher molecular weight epoxy resins or hydroxy- terminated polyethers from liquid epoxy resins, which improvements significantly alleviate or do not incur the problems and disadvantages discussed above.

It is another object of the present invention to provide a continuous process for making higher molecular weight epoxy resins or hydroxy-terminated polyethers from lower molecular weight epoxy resins in the presence of a solvent system with less gel formation and having uniform consistency. Another object of the present invention resides in a continuous method for upstaging the molecular weight of thermosetting resinous polyepoxides or hydroxy-terminated polyethers .

A further object of the present invention relates to a continuous process for upstaging thermosetting liquid resinous polyepoxides or hydroxy-terminated polyethers which uses sequentially staged reactors.

Other and more particular objects of the present invention will become apparent to one skilled in the art from the following summary of the invention and description of the preferred embodiments.

The present invention relates to a continuous process for upstaging epoxy resins or hydroxy-terminated polyethers, which process comprises continuously passing a feed solution comprising (i) a liquid epoxy resin, (ii) a compound having active hydrogens or reaction functional groups capable of reacting with a liquid epoxy resin such as polyhydric phenolic compound, (iii) an inert solvent or diluent such as acetone, xylene, or a mixture thereof, and (iv) a catalyst such as triphenyl phosphonium ethyl iodide catalyst through reaction chamber (s), such as a series of pipe reactors, optionally having mixing means such as static mixing means or dynamic mixing means, to produce a product stream comprising product epoxy resin or hydroxy-terminated polyethers; and removing said solvent from said product stream; wherein the equivalency ratios of said epoxy resin to said compound having active hydrogens or reaction functional groups capable of reacting with a liquid epoxy resin is from 3.3:1 to 0.5:1, preferably from 2.6:1 to 0.6:1, more preferably from 1.6:1 to 0.65:1; wherein said product resin or hydroxy-terminated polyether has a molecular weight higher than the liquid epoxy resin in the feed solution; wherein said feed solution comprises from 5 to 80, preferably from 5 to 50 percent, more preferably from 5 to 25 percent by weight of said solvent; wherein the reaction temperature in the reactors is from 49 °C (120 °F) to 216 °C (420 °F) , more preferably from 82 °C (180 °F) to 216 °C (420 °F) , and most preferably from 93 °C (200 °F) to 204 °C (400 °F) .

In particular, the present invention is directed to a process for the continuous upstage or upgrade of epoxy resins. It has been found now that by incorporating an inert solvent into the continuous reaction system, one could employ one or more simple and inexpensive reactor (s), with static-mixers or dynamic mixer (s), to make fusion resin solutions, without having to resort to the use of the more expensive reactors, such as extruder- reactor (s). Since longer residence time can be designed into this type of reactor, the catalyst amount used does not have to be elevated to a similarly high level as that used in certain prior art solventless continuous processes using the extruder-reactors. An additional advantage of the present process resides in the fact that the solvent in the reaction system also serves as a heat sink for the high exotherm released from this type of reactions. The resulting solution product can be diluted to the desired concentration, or blended with other additives or components as necessary to give the final product. In the case where solid products are required, it is certainly possible to remove the solvent by post- reaction evaporation, followed by solidifying the product accordingly.

Another advantage of the present invention is that, the feeds to the reaction system can be in the solution form (e.g., liquid EPON Resin 828, and BPA or TBBPA-based solutions where the solvent and the catalyst are combined with the respective phenolic components) for easier handling, especially in grassroot plants e.g., no solids dust handling to minimize potential for explosion and accurate metering.

As one illustrative embodiment of the present invention, a Continuous Solution Reaction Unit consisting of a single jacketed pressure feed vessel with an air- driven mixer, a feed pump, a series of four heat-traced pipe reactors with internal static elements, a heat exchanger pipe for cooling the exiting reaction product, and a back pressure regulator is used. A schematic diagram of the reaction system is shown in Figure 1. As specific aspects of the illustrative embodiment, the feed, consisting of the raw materials, catalyst and the solvent, is prepared externally in a 4-neck flask equipped with a stirrer, a thermocouple, and a condenser. Solid reactant and liquid epoxy resin are charged, mixed followed by the addition of solvent. Heat is applied only as needed. Upon full dissolution of the solids, catalyst is added and uniformly mixed into the solution. This reaction premix is then transferred into the feed vessel (pre-warmed as needed via the heat jacket), gently deaerated with nitrogen (pressurizing the vessel to 2.72 bar (25 psig) and released to <1.35 bar (<5 psig) , repeated another 2 times, and finally pressurizing to 2.04-2.72 bar (15-25 psig) nitrogen atmosphere). The instant process exhibits good stability of reaction premix at the feed temperature over the duration of a typical continuous run (<12 hours) . An illustrative example of premix stability results are given in Table 1. Other suitable methods, which can be used by one skilled in the art, for making reaction premix and/or for feeding to the feed vessel are also within the scope of the present process.

As a specific aspect of the present process, liquid epoxy resin feed and the compound having active hydrogen (s) are separately charged to the continuous reactor; the compound having active hydrogen (s) can be mixed with the inert solvent and catalyst before injected into the reactor. As another specific aspect of the present process, the liquid epoxy resin feed, the compound having active hydrogen (s) and the inert solvent can be premixed, and the premix is injected to the reactor (s) separately from the catalyst.

The present process may utilize one reaction chamber or reactor, with one or more reaction zones, or two or more reaction chambers or reactors, each with one or more reaction zones. As a non-limiting illustrative example, a pipe reactor or a plurality of two or more staged pipe reactors with mechanical mixing means can be utilized. As illustrative examples, the mechanical mixing means include, but not limit to, static mixing element (s) and dynamic mixer (s) .

The reaction chamber (s) or reactor (s) can optionally be heat traced by setting heat-tracing on the reactors or reaction chamber (s) and controlling temperature (s) via controllers. The premix solution is delivered, e.g. via the diaphragm pump, continuously through a reaction chamber or a plurality of reactors in which the coupling reaction takes place.

The feed rate is gradually increased to the targeted flow rate and the temperature of each of the reaction zones is optionally adjusted as needed due to exotherm. Optionally, flow rates are checked during the run, and samples are taken, e.g. after 3-5 turnovers and analyzed. Heat tracing may be applied in the reaction chamber (s) or reactor (s) to control the temperature in reaction zone(s) in the reaction chamber (s) or reactor (s) . As a preferred embodiment of the present invention, the temperature in the reactor (s) or chamber (s) will generally stay below 232 °C (450 °F), preferably below 216 °C (420 °F) and most preferably below 204 °C (400 °F) . Heat is generated during the fusion process, therefore the temperature is higher at the latter stages of the process than that at the beginning stage. The temperatures in the reaction chamber (s) or reactors are typically from 49 °C (120 °F) to 216 °C (420 °F), preferably from 82 °C (180 °F) to 216 °C (420 °F) , more preferably from 93 °C (200 °F) to 204 °C (400 °F) .

The duration of the fusion reaction, i.e. the amount of time the reactants/feedstock stay in the reaction chamber (s) before it is discharged as the product stream, is typically from 10 minutes to 180 minutes, preferably from 20 minutes to 120 minutes, and more preferably from 30 minutes to 60 minutes.

The present Continuous Solution Reaction Unit can be utilized to produce a variety of resin products. Illustrative non-limiting examples of inert solvents which are suitable for preparing the reactive feedstock (liquid epoxy resin and phenolic components, with catalyst such as ethyl triphenyl-phosphonium iodide or triphenyl phosphine) , include, but not limited to, acetone and xylene . As an illustrative aspect of the present process, suitable inert solvents include, but by no means limited to, a solvent capable to solubilize the reactant epoxy resin (s). The Reaction Unit is normally filled, flushed and cleaned with the solvent to be used in the next run from the feed vessel using the diaphragm pump. After cleaning the reactors, the pump is stopped, and excess solvent drained from the feed vessel. The feed vessel is then charged with the reaction mixture (see Feed Preparation section above) , and fed through the reaction vessel via the pump. In addition to acetone and xylene, other solvents which can be used in the practice of the present invention include, but by no means limited to, benzene, toluene, sulpholane, diethylether, tetra- hydrofuran, dimethoxyethane, C5-C10 aliphatic hydro- carbons including all the branched isomers, ethylbenzene, cumene, 2-butanone and 2-methyl tetrahydrofuran, as well as mixtures thereof.

The reaction mixtures typically contain from 5 to 80 percent, preferably from 5 to 50 percent, and more preferably from 5 to 25 percent by weight of solvent (s) or diluent (s). The ratio of the equivalent of catalyst to the equivalent of epoxy employed in the reaction mixture is typically from 5xl0^~5 to 2xl0^~3, preferably from lxl0^~ to lxl0-3, and most preferably from 1.5x10"^ to 5xl0^~4.

The equivalency ratio of liquid epoxy resin to the compound having active hydrogen (s) or reactive function groups capable of reacting with a liquid epoxy resin is from 3.3:1 to 0.5:1, most preferably from 1.6:1 to 0.65:1. As a specific embodiment of the present invention, the equivalent ratio of liquid epoxy resin to the compound having active hydrogen (s) or reactive function groups capable of reacting with a liquid epoxy resin is from 3.3:1 to 1.3:1, more preferably from 2.7:1 to 2.5:1 to produce the product epoxy resin with advanced molecular weight .

Illustrative examples of the suitable starting materials having an average of more than one vicinal epoxy group per molecule which can be employed in the process of the present invention include, for example, those represented by the formulas:

II

wherein each A is independently a divalent hydrocarbyl group having from 1 to 10, preferably from 1 to 6 carbon atoms, more preferably R^-C-R², wherein R¹ and R² are methyl or hydrogen; or A can be;

each R is independently hydrogen or a hydrocarbyl group having from about 1 to about 4 carbon atoms; X is independently hydrogen, a halogen, preferably chlorine or bromine, or a hydrocarbyl or hydrocarbyloxy group having from 1 to 12 carbon atoms; n has a value of zero or 1; and q has an average value of from zero to 2, preferably from zero to 0.3. When the functionality of the epoxy resin is higher than 2, they are employed in combination with an epoxy resin having a functionality of 2 and is employed in small quantities with respect to the 2 functional material.

The term hydrocarbyl group means any aliphatic, cycloaliphatic or aromatic hydrocarbon group, which consists of hydrogen and carbon atoms. Likewise, the term hydrocarbyloxy group means those compounds represented by the formula —OR wherein R is a hydrocarbyl group as above defined.

Particularly suitable epoxy-containing materials include the glycidyl ethers of polyhydric phenols such as resorcinol, catechol, hydroquinone, bisphenol-A, bisphenol-F, tris-hydroxyphenyl methane, 2, 6, 2 ' , 6 ' -tetra- bromo-p, p ' -bisphenol-A, 2 , 6, 2 ' , 6 ' -tetramethyl-3, 5,3'- tribromo-p, p ' -biphenol, 2, 6, 2 ' , 6 ' -tetramethyl-3, 5, 3 ' , 5 ' - tetrabromo-p, p ' -biphenol, tetramethylbiphenol, bisphenol-E, mixtures thereof and the like.

As one embodiment of the present invention, particularly preferred liquid resinous polyepoxides generally possess a q value averaging less than 1, i.e., a liquid resinous polyepoxide consisting essentially of the diglycidyl ether of bisphenol-A. Such a polyepoxide may have a weight per epoxide equivalent value between 180 and 240. The term "liquid" means that the initial polyepoxide is in the liquid state at ambient conditions, i.e., 25 °C and 1 bar (760 mmHg) . As indicated above, these polyepoxides are characterized by weight per epoxide equivalent values. Weight per epoxide equivalent or "WPE" is defined and used herein to indicate the grams of resinous polyepoxide containing one gram equivalent of epoxy groups . Weight per epoxide equivalent is determined by the procedures described in "Epoxy Resins", pp. 133-135, Burge, Jr. and Geyer, Analytical Chemistry of Polymers, Part I, Kline, Ed. (Interscience 1959) .

The other reactant materials to make the resins of the present invention are preferably polyhydric phenolic materials which include, as non-limiting illustrative examples resorcinol, catechol, hydroquinone, bisphenol-A, bisphenol-F, dihydroxybiphenyl, tris-hydroxyphenyl methane, 2 , 6, 2 ' , 6 ' -tetrabromo-p, p ' -bisphenol-A, 2, 6, 2 ' , 6 ' -tetramethyl-3, 5,3' -tribromo-p, p ' -biphenol,

2 , 6, 2 ' , 6 ' -tetramethyl-3, 5, 3 ' , 5 ' -tetrabromo-p, p ' -biphenol, tetramethyl biphenol, bisphenol-E, mixtures thereof and the like.

The amount of dihydric phenol and initial resinous polyepoxide to be employed in the process may vary over a wide range depending upon the type of reactants and the type of product to be desired. For example, the polyepoxide and the dihydric phenol reactants may be used in equivalency ratios of epoxide groups to phenolic (Ar—OH) of from 3.3:1 up to 0.5:1, more typically from 2.6:1 to 0.6:1, and preferably from 1.6:1 to 0.65:1. Although the other preferred reactant of the present invention is a polyhydric phenolic material, other compounds having active hydrogens or other reactive groups may be used in the practice of the instant invention. Such compounds containing groups reactive with the epoxy-containing material include, for example, those materials which contain an average of more than one organic hydroxyl, thiol, carboxyl, isocyanate, thioisocyanate or secondary amine group or any combination of such groups per molecule and those materials which contain only one primary amine group per molecule. These materials can be aliphatic or aromatic.

Suitable -COOH containing materials include dicarboxylic acids such as, for example, malonic acid, succinic acid, maleic acid, terephthalic acid, dinicotinic acid, mixtures thereof and the like.

Suitable materials containing thiol (—SH) groups include, as illustrative non-limiting examples, the thiol analogs to the aforementioned hydroxyl-containing materials. Particularly suitable thiol materials include, for example, 1, 4-dimercaptobenzene, 1, 3-dimercapto- benzene, 1, 2-dimercaptobenzene, ethylene mercaptan, 1, 3-propanedithiol, 1, 4-butanedithiol, mixtures thereof and the like.

Suitable materials containing isocyanate groups include, but not limited to, any isocyanate-containing material such as aromatic or aliphatic or cycloaliphatic isocyanate-containing materials. Particularly suitable isocyanate-containing materials include, for example, hexamethylene-1, 6-diisocyanate, benzene-1, 4-diisocyanate, toluene diisocyanate, methylenediphenylisocyanate, mixtures thereof and the like.

Suitable materials containing thiocyanate groups include, as non-limiting illustrative examples, the thiol analogs to the aforementioned isocyanate-containing materials. Particularly suitable thiol materials include, for example, hexamethylene-1, 6-dithiocyanate, benzene-1, 4- dithiocyanate, toluenedithiocyanate, methylene- diphenylthiocyanate, mixtures thereof and the like.

Suitable materials containing secondary amine groups include any aromatic or aliphatic or cycloaliphatic secondary amine-containing materials. Particularly suitable secondary amine-containing materials include, as illustrative and non-limiting examples, piperazine, ethoxylated ethylenediamine, mixtures thereof and the like .

Particularly suitable materials which contain only one primary amine group per molecule include, as non- limiting illustrative examples, aniline, halogenated and alkylated aniline, hexylamine, heptylamine, long chain aliphatic amine, cyclohexylamine, cycloheptylamine and alkylated cyclicamine, mixtures thereof and the like.

As shown above for the dihydric phenol, the amounts of other reactive materials and initial resinous polyepoxide to be employed in the process may vary over a wide range depending upon the type of reactants and the type of products. For example, the compound having reactive functional groups and the polyepoxide reactants may be used in equivalency ratios of epoxy groups to reactive functional group of from 3.3:1 to 0.5:1, more typically from 2.6:1 to 0.6:1, and most preferably from 1.6:1 to 0.65:1.

The preferred fusion catalysts that are useful in the practice of the present invention include but not limited to the tetra organic substituted phosphonium halides of the tri-organic radical substituted phosphines and the like. Preferred phosphonium halides are those conforming to the formula :

Rl R₂

\

P X

R3 R4

wherein X is a halogen atom, and R]_, R₂, 3 and R4 are the same or different and represent hydrocarbon residues which may or may not be substituted by one or more functional groups, such as halogen atoms. These phosphonium halides may generally be prepared by mixing in approximately equimolar proportions of a phosphine with a halide. The mixing may be carried out with or without the application of heat, alone or in the presence of an inert solvent such as, for example, diethylether, benzene, chloroform or carbon tetrachloride . Preferred phosphines include but not limited to the organic phosphines, i.e., compounds of the formula

P(R)₃ wherein at least one R is an organic radical and the other R's are hydrogen or organic radicals and preferably hydrocarbon radicals or substituted hydrocarbon radicals which may contain no more than 25 carbon atoms.

Illustrative examples of the phosphines include but not limited to triphenyl phosphine, tri (tolyl) phosphine, tributyl phosphine, trilauryl phosphine, tricyclohexyl phosphine, trihexyl phosphine, triallyl phosphine, tridodecyl phostrieicosadecyl phosphine, trichlorobutyl phosphine, triethoxybutyl phosphine, trihexenyl phosphine, trixylyl phosphine, trinaphthyl phosphine, tricyclohexenyl phosphine, tri (3, 4-diethyloctyl) - phosphine, trioctadecyl phosphine, dioctyldecyl phosphine, dicyclohexyl phosphine, dibutyl allyl phosphine and the like, and mixtures thereof.

Particularly preferred phosphines to be employed include the trihydrocarbyl, dihydrocarbyl and monohydrocarbyl phosphines wherein the hydrocarbyl radicals (hydrocarbon radicals) contain from 1 to

18 carbon atoms, and more particularly those wherein the hydrocarbon radicals are alkyl cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl, arylalkyl, and the like radicals. Coming under special consideration are the phosphines containing at least one and preferably three aromatic radicals.

Compounds to be mixed with the phosphine in the preparation of the phosphonium halide catalyst include, but not limited to, organic halides. Preferred organic halides are those wherein the organic radical is a hydrocarbon radical, preferably having from 1 to 10 carbon atoms. Illustrative non-limiting examples of preferred organic halides include methylchloride, ethyl chloride, methyl bromide, ethyl bromide, methyl iodide, ethyl iodide, propyl iodide, n-butyl iodide, sec-butyl iodide and n-decyl iodide, and the like, and mixtures thereof . Examples of the above-noted phosphonium catalysts include, among others, methyltriphenyl phosphonium iodide, ethyltriphenyl phosphonium iodide, propyl- triphenyl phosphonium iodide, n-butyltriphenyl phosphonium iodide, iso-butyltriphenyl phosphonium iodide, sec-butyltriphenyl phosphonium iodide, n-pentyltriphenyl phosphonium iodide, n-decyltriphenyl phosphonium iodide, methyl tributyl phosphonium iodide, ethyltributyl phosphonium iodide, propyl tributyl phosphonium iodide, methyl triphenyl phosphonium chloride, ethyl tri(p-tolyl) phosphonium chloride, ethyl tri(p-tolyl) phosphonium iodide, isobutyl tri(p-tolyl) phosphonium chloride, isobutyl tri(p-tolyl) phosphonium iodide, ethyl triphenyl phosphonium chloride, propyl tributyl phosphonium iodide, n-butyl triphenyl, ethyl triphenyl phosphonium chloride and ethyl triphenyl phosphonium bromide, and the like, as well as mixtures thereof .

It should be noted that the phosphines could also be used without further modification as catalysts of the present invention. Non-limiting examples of such phosphines include triphenylphosphine, tri-p-tolyl- phosphine, tris-p-chloro-phenylphosphine, tri-n-butyl- phosphine, dibutylallylphosphine, trilaurylphosphine, trihexenylphosphine, tridodecylphosphine, dicyclohexyl- phosphine, trinaphthyl-phosphine, triethoxybutyl- phosphine, tris-p-methoxyphenylphosphine, tris-p-fluoro- phenylphosphine, and the like, as well as mixtures thereof.

The amount of the fusion catalyst will vary over a wide range. In general, amount of catalyst will vary from

5xl0^-5 to 2xl0^-3, preferably from lxlO^-4 to lxlO^-3, and most preferably from 1.5xl0^-4 to 5xl0^-4 based on ratio of equivalent of catalyst to the equivalent of epoxy employed in the reaction mixture. The reaction conditions at each reaction zone may be maintained, i.e., the polyepoxide may be allowed to increase in molecular weight and weight per epoxide equivalent, for a period of time sufficient to produce the thermosetting polyepoxide, phenoxy-terminated resin, or hydroxy-terminated polyether upstaged or advanced to the desired molecular weight or weight per epoxide equivalent. For example, when the final product has the structural formula II as shown above where X is hydrogen and n is 0 have the meaning given above, the average value of q may be allowed to increase by at least 2, and preferably by 4 to 12, from its initial value.

As an illustrative embodiment of the present invention, the molecular weight of the feed epoxy resin is from 340 to 800 preferably from 360 to 450, and most preferably from 370 to 420. The fused product epoxy resin has an average molecular weight from 600 to 10000, preferably from 800 to 6000 and most preferably from 900 to 5000.

The following illustrative embodiments (examples) will more fully illustrate the embodiments of this invention. Therefore, they should not be construed as limiting the remainder of the disclosure in any way. All parts, percentage and proportions referred to herein and in the appended claims are by weight unless otherwise indicated. The liquid EPON Resin 828 used in the examples has a typical epoxy content of 185-192 g/eq epoxy.

The Continuous Solution Reaction Unit consists of a single jacketed pressure feed vessel with an air-driven mixer, a feed pump, a series of four heat-traced pipe reactors (at 50, 100, 100, 100 ml volumes respectively) with internal static elements, a heat exchanger pipe (100 ml volume) for cooling the exiting reaction product, and a back pressure regulator. A schematic diagram is shown in Figure 1. EXAMPLES 1-12

The feed, consisting of the raw materials, catalyst and the solvent, is prepared externally in a 4-neck flask equipped with a stirrer, a thermocouple, and a condenser. Solid reactant and liquid epoxy resin are charged, mixed followed by the solvent. Heat is applied only as needed. Upon full dissolution of the solids, catalyst is added and uniformly mixed into the solution. This reaction premix is then transferred into the feed vessel (pre- warmed as needed via the heat jacket) , gently deaerated with nitrogen (pressurizing the vessel to 25 psig and released to <5 psig, repeated another 2 times, and finally pressurizing to 15-25 psig nitrogen atmosphere) . Based on the studies, the stability of reaction premix at the feed temperature over the duration of a typical continuous run (<12 hours) is deemed acceptable. The premix stability results of Examples 1-12 are given in Table 1. Continuous Reaction Experiments The Continuous Solution Reaction Unit can be utilized to produce a variety of resin products. Acetone and xylene are the primary solvents in the preparation of the reactive feedstock (liquid epoxy resin and phenolic components, with catalyst such as ethyl triphenyl- phosphonium iodide or triphenyl phosphine) . The Reaction Unit is normally filled, flushed and cleaned with the solvent to be used in the next experiment from the feed vessel using the diaphragm pump. After cleaning the reactors, the pump is stopped, and excess solvent drained from the feed vessel. The feed vessel is then charged with the reaction mixture (see Feed Preparation section above) .

After the heat-tracing on the reactors are set and controlled via controllers, the premix solution is delivered via the diaphragm pump continuously through a series of heat-traced static mixer-reactors in which the coupling reaction takes place. The feed rate is gradually increased to the targeted flow rate and the temperature of each of the reaction zones is fine-adjusted as needed due to exotherm. Flow rates are checked during the run, and samples are taken after 3-5 turnovers (1400-2200 ml) and analyzed.

Given in the following examples are the premixture compositions. The operating conditions and results are summarized in Table 2. EXAMPLE 13

Premix Composition:

EPON Resin 828, g: 2394

Bisphenol-A (BPA) , g: 756 Triphenyl phosphonium ethyl iodide, g: 1.9

Solvent, g: 350 (acetone)

Feed vessel temperature, °F: 94 EXAMPLE 14

Premix Composition: EPON Resin 828, g: 2394

Bisphenol-A (BPA), g: 756

Triphenyl phosphonium ethyl iodide, g: 2.4

Solvent, g: 161 (acetone)

Feed vessel temperature, °F: 94 EXAMPLE 15

Premix Composition:

EPON Resin 828, g: 2394

Bisphenol-A (BPA), g: 756 Triphenyl phosphonium ethyl iodide, g: 2.4

Solvent, g: 161 (acetone)

Feed vessel temperature, °F: 94 EXAMPLE 16

Premix Composition: EPON Resin 828, g: 2262

Bisphenol-A (BPA), g: 714

Triphenyl phosphonium ethyl iodide, g: 2.7

Solvent, g: 526 (xylene)

Feed vessel temperature, °F: 177 EXAMPLE 17

Premix Composition:

EPON Resin 828, g: 2262

Bisphenol-A (BPA), g: 714

Triphenyl phosphonium ethyl iodide, g: 2.7 Solvent, g: 526 (xylene)

Feed vessel temperature, °F: 177 EXAMPLE 18

Premix Composition:

EPON Resin 828, g: 1939 Bisphenol-A (BPA), g: 612

Triphenyl phosphonium ethyl iodide, g: 2.3

Solvent, g: 450 (xylene)

Feed vessel temperature, °F: 130 EXAMPLE 19 Premix Composition:

EPON Resin 828, g: 2520

Bisphenol-A (BPA), g: 7796

Triphenyl phosphonium ethyl iodide, g: 3.0

Solvent, g: 586 (xylene) Feed vessel temperature, °F: 133 EXAMPLE 20

Premix Composition: EPON Resin 828, g: 2068 Bisphenol-A (BPA), g: 653 Triphenyl phosphonium ethyl iodide, g: 2.5

Solvent, g: 480 (xylene) Feed vessel temperature, °F: 159 EXAMPLE 21

Premix Composition: Low Molecular weight solid epoxy resin @ 535 g/eq epoxy, g: 3144 Bisphenol-A (BPA), g: 465

Triphenyl phosphonium ethyl iodide in ethanol as 15 %w solution, g: 14.4 Solvent, g: 792 (xylene)

Feed vessel temperature, °F: 162 EXAMPLE 22

Premix Composition: EPON Resin 828, g: 1573 Bisphenol-A (BPA), g: 832

Triphenyl phosphonium ethyl iodide in ethanol as

15 %w solution, g: 15.9 Solvent, g: 424 (xylene) Feed vessel temperature, °F: 99 EXAMPLE 23

Premix Composition: EPON Resin 828, g: 2385 Bisphenol-A (BPA), g: 959

Triphenyl phosphonium ethyl iodide in ethanol as 15 %w solution, g: 20.2

Solvent, g: 372 (acetone) Feed vessel temperature, °F: 96 EXAMPLE 24

Premix Composition:

EPON Resin 828, g: 1308

Tetrabromo bisphenol-A (TBBPA) , g: 1248 Triphenyl phosphine, g: 1.4

Solvent, g: 450 (acetone)

Feed vessel temperature, °F: 103 EXAMPLE 25

Premix Composition: EPON Resin 828, g: 1692

Tetrabromo bisphenol-A (TBBPA), g: 1623

Triphenyl phosphine, g: 1.8

Solvent, g: 585 (acetone)

Feed vessel temperature, °F: 103 EXAMPLE 26

Premix Composition:

EPON Resin 828, g: 2603

Tetrabromo bisphenol-A (TBBPA), g: 2499

Triphenyl phosphine, g: 2.8 Solvent, g: 900 (acetone)

Feed vessel temperature, °F: 86

The experimental data obtained as a result of carrying out all of the above examples is summarized in Tables 1-2 below. The products produced have excellent product consistency. The process is low in equipment costs and much less labor-intensive than the conventional processes . TABLE 1. CONTINUOUS SOLUTION FUSION STUDIES - PREMIX STABILITY

BPA/Liquid Epoxy resin

TABLE 1 (cont'd). CONTINUOUS SOLUTION FUSION STUDIES - PREMIX STABILITY

BPA/Liquid Epoxy resin

ts

TBBPA/Liquid Epoxy resin

1. Acetone: regular font, Xylene: Bold, Italic and Underlined

2. WPE: Solution WPE.

Table 2. Continuous Solution Reaction studies BPA/EPON Resin 828 or low molecular weight solid epoxy resin

Table 2 (cont'd). Continuous Solution Reaction studies BPA/EPON Resin 828 or low molecular weight solid epoxy resin

TBBPA/EPON Resin 828

1. Acetone: regular font, Xylβne:Bold, Italic and Underlined

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention. A further understanding of the nature and advantage of this invention herein may be realized by reference to the remaining portions of the specification and the appended claims. Also it is to be understood that the forms of the invention herein are to be taken as preferred examples of the same and that various changes may be made without departing from the spirit of the invention or scope of the subjoined claims.

Claims

C L A I M S

1. A continuous process for upstaging epoxy resins, which process comprises: continuously passing a feed solution comprising (i) a liquid epoxy resin, (ii) a compound having active hydrogen (s) or reactive functional group (s) capable of reacting with a liquid epoxy resin, (iii) an inert solvent, and (iv) a catalyst through reaction chamber (s) to produce a product stream comprising product resin; wherein said feed solution comprises from 5 to 80 percent by weight of said solvent; wherein the equivalency ratios of said liquid epoxy resin to said compound having active hydrogen (s) or reactive functional group (s) introduced into reaction zone(s) being from 3.3:1 to 0.5:1; wherein said product resin has a molecular weight higher than the liquid epoxy resin in (a) .

2. The process of claim 1, wherein said reaction chamber (s) comprises a series of sequentially staged reaction chambers.

3. The process of claim 2, wherein said reaction chambers are a series of pipe reactors having mixing means .

4. The process of claim 3, wherein said mixing means is selected from the group consisting static mixer, dynamic mixer, and combination thereof.

5. The process of claim 1, wherein the solvent is selected from the group consisting of xylene, acetone, and mixture thereof.

6. The process of claim 1, wherein said reaction chamber is a reactor comprising a plurality of reaction zones.

7. The process of claim 1, wherein the temperature in the reaction chamber (s) is from 49 °C (120 °F) to 216 °C (420 °F) .

8. The process of claim 1, wherein said liquid epoxy resin is the diglycidyl ether of bisphenol-A, and said compound having active hydrogen is selected from the group consisting of bisphenol-A, tetrabromobisphenol-A or mixtures thereof, said catalyst is triphenyl phosphonium ethyl iodide .

9. A continuous process for upstaging epoxy resins, which process comprises: continuously passing a feed solution comprising (i) a liquid epoxy resin, (ii) a polyhydric phenolic compound, (3) a solvent selected from the group consisting of acetone, xylene, and mixtures thereof, and (4) a triphenyl phosphonium ethyl iodide catalyst through a series of pipe reactors having static mixing means or dynamic mixing means to produce a product stream comprising product resin; and (a) removing said solvent from said product stream; wherein said feed solution comprises from 5 to 25 percent by weight of said solvent; wherein the reaction temperature in the reactors is from 93 °C (200 °F) to 204 °C (400 °F) ; wherein the equivalency ratios of said liquid epoxy resin to said polyhydric phenolic compound is from 1.6:1 to 0.65; wherein said product resin has a molecular weight higher than the liquid epoxy resin in (a) .