KR860002038B1 - Stable dispersions of organic polymers in polyepoxides and a process for preparing such dispersions - Google Patents

Abstract

The title dispersion soln., whose viscosity is low and whose softening temp. is low, too, is prepd. Organic polymers which are polymerization products of unsaturated ethylene monomer form insoluble dispersed phase above 60≰C in polyepoxide. The size of dispersed particle is less than 20 μm. The amount of dispersed organic polymer is 5-70 wt.% of total dispersion soln.. The size and distribution of the dispersed particles are easily controlled.

Description

Stable Dispersion of Organic Polymers in Polyepoxides and Methods for Producing the Same

The present invention relates to a stable dispersion of organic polymers in a polyepoxide in a continuous phase and a process for producing such a dispersion.

Polyepoxides, also known as epoxy resins, are coatings, adhesives, fiber reinforced laminates, composites. It has a variety of properties that are well suited for use in specialty applications such as engineering plastics and potting resins and mortars. Among these properties are corrosion resistance, solvent resistance, good adhesion and electrical properties. There are good size stability, hardness, low cure shrinkage, and many other beneficial properties. Their main disadvantage is that they break well. Known as a solution to this problem is the addition of reactive liquid polymers (RPP). These are generally elastomers, such as carboxyl-terminated butadiene-acrylonitrile copolymers, which precipitate out of solution from precipitation upon curing of the polyepoxide. This precipitation forms dispersed elastomeric particles or bands that make the resin tough. This toughening technique of the cured resin significantly lowers the softening temperature. Particle size is a major factor in determining mechanical properties. The selectivity and reactivity of functional groups have a significant effect on the formation of particles. Curing conditions also have a serious effect on their size and structure. Another disadvantage is that the RLP is limited to low molecular weight to ensure good mixing and low viscosity.

European Patent Application No. 78,528, prioritizing US Patent Application No. 316,469 / 81, describes a composition for forming an epoxy adhesive containing acrylate rubber. Examples in this patent application use rubber made from butyl acrylate. These rubbers are soluble in the epoxy resins used in these examples at temperatures above 51 ° C.

Methods or techniques that can improve the toughness of the cured polyepoxide side without damaging other properties may greatly expand the usefulness of this class of resins. It is particularly desirable to be able to adjust the particle size more appropriately, to have more incompatible particles, and to have higher heat distortion temperatures. It is also desirable to have polymer-modified polyepoxides that have a lower viscosity than RLP modified polyepoxides and are more workable.

According to the present invention there is provided a stable dispersion of an organic polymer in a polyepoxide in a continuous phase, characterized in that the dispersed phase remains insoluble at a temperature of at least 60 ° C, preferably at least 90 ° C, in the polyepoxide side. . The dispersed phase is a one-step reaction (condensation reaction). Cationic. It can be prepared by polymerizing one or more monomers by addition reactions such as anionic or coordination polymerization reactions, or by free radical chain addition reactions. Preferably the dispersion is a polymer of ethylenically unsaturated monomers polymerized in situ. Moreover, it is preferable that a dispersion liquid contains a dispersion stabilizer.

Another aspect of the invention is (1) reacting a small amount of functional monomer with polyepoxide to produce a vinylation adduct, and (2) reacting the resulting vinylation adduct with an ethylenically unsaturated monomer to provide a dispersion stabilizer. And (3) polymerizing the ethylenically unsaturated monomer in the presence of a dispersion stabilizer in the polyepoxide to prepare a dispersion of the organic polymer, the method for producing a stable dispersion as described above. It is about. Alternatively, steps (2) and (3) are performed simultaneously. Alternatively, a dispersion stabilizer may be prepared separately and added to the polyepoxide before the addition of the ethylenically unsaturated monomer and before or during the polymerization reaction. Preferably, (a) the particles of the dispersion do not solidify or aggregate during or during the curing process: (b) the particles have a controlled particle size: (c) the dispersion can be stored for a suitable period without premature curing.

Factors controlling the stability of the dispersion of the present invention include the viscosity of the polyepoxide (the larger the viscosity, the greater the stability). Particle size (the smaller the particle size, the greater the stability). Density difference of phase (the smaller the density difference, the greater the stability). Aggregation tendency of the particles (the smaller the aggregation tendency of the particles, the greater the stability). The presence of stabilizers, and the absence of flocculants. Stability also depends on the particular combination of polyepoxide and organic polymer or copolymer.

As described herein, those skilled in the art will appreciate that if a stable dispersion is not produced by the polymerization of certain monomers in certain polyepoxides in liquid form, the dispersion stabilizer may be added or the polymerization process may be altered. It will be appreciated that the stability can be improved.

The dispersion of the present invention has the following advantages over solutions of organic polymers in polyepoxides:

(1) Dispersions often have a lower viscosity than polymer solutions at constant solid concentrations.

(2) The dispersion contains less soluble substances in the curved matrix, and thus the softening temperature is higher.

(3) In the case of dispersions, the size and distribution of the dispersed particles in the curved matrix can be better controlled.

Any known polyepoxide can be used for the preparation of the resin composition. Useful polyepoxides include polyglycides such as polyglycidyl ethers of polyhydric alcohols and polyphenols, polyglycidyl esters, tetraglycidyl ethers of methylene dianiline, so long as they contain an average of one or more epoxide groups per molecule. Cydyl amine, polyglycidylamide, polyglycidyl imide, polyglycidyl hydantoin, polyglycidylthioether, epoxidized ester of fatty acid or dry oil, epoxidized polyolefin. Epoxidized di-unsaturated esters, epoxidized unsaturated polyesters and mixtures thereof. The polyepoxide may be a monomer or a polymer.

If polyhydric phenols are chosen for the production of polyepoxides, there may be several structural aspects. Polyepoxides made from polyhydricphenols may contain bisphenol groups in which the linking radical is an oxide of lower alkylene, sulfur, oxygen, carbonyl or sulfur. Aromatic rings can be independently substituted with lower alkyl, alkylene, or halides such as chlorine or bromine.

Other polyhydric phenols include mononuclear and trivalent phenols such as resorcinol, hydroquinone, catechol, phloroglucinol and pyrogallol.

Still other polyhydric phenols are novolacs in which phenol or substituted phenols are combined with hydrocarbon groups.

Another example of a high functional polyepoxide is tris (glycidylphenyl) methane.

Polyepoxides, referred to as epoxidized diolefins or epoxidized esters of fatty acids, are generally prepared by known peracid methods, in which the reaction is temperature controlled such that the acid produced from the peracid does not react with the resulting epoxide groups. Is one of the epoxidation reactions of a compound with separated double bonds, forming ester bonds and hydroxyl groups. The preparation of polyepoxides by the peracid method is described in various documents and patents. Compounds such as butadiene polymers, ethyl linoleate, polyunsaturated dry oil or dry oil esters can all be converted to polyepoxides.

Other polyepoxides include epoxidized cycloolefins. These polyepoxides can be prepared by epoxidizing the cyclic olefin material by known peracid methods.

Examples of polymeric polyepoxides include polymers and copolymers of glycidyl acrylate, glycidyl methacrylate and allylglycidyl ether.

The present invention can be applied to polyepoxides, but generally preferred polyepoxides are glycidyl polyethers of polyhydric phenols or polyalcohols having a weight of 150 to 20,000 per epoxide group. These polyepoxides typically react with at least about 2 moles of epihalohydrin or glycerol dihalohydrin with an amount of caustic alkali sufficient to bind 1 mole of polyhydric alcohol or polyhydric phenol and the halogen of halohydrin. To make it. The product is characterized by the presence of one or more epoxide groups, ie greater than 1 of the 1,2-epoxy equivalent.

Other methods of modification are known to those skilled in the art.

Polyepoxides may also contain small amounts of monoepoxides such as butyl glycidyl ether, phenyl glycidyl ether or cresyl glycidyl ether as reactive diluents. Such reactive diluents are typically added to the polyepoxide side compositions to reduce their processing viscosity and to impart better wettability to the compositions. As is known in the art, monoepoxides affect the stoichiometry of polyepoxide side compositions and are controlled by the amount of curing agent and other variables reflecting these changes.

Examples of ethylenically unsaturated monomers that can be used include butadiene, isoprene, 1,4-pentadiene, 1,6-hexadiene, 1,7-octadiene, styrene, α-methylstyrene, methylstyrene, 2,4-dimethyl Styrene, ethyl styrene, isopropyl styrene, butyl styrene, phenyl styrene, cyclohexyl styrene and benzyl styrene; Chlorostyrene, 2,5-dichlorostyrene, bromostyrene, fluorostyrene, trifluoro-methylstyrene, iodostyrene, cyanostyrene, nitrostyrene, N, N-dimethyl-aminostyrene, acetoxyl styrene, methyl- Substituted styrenes such as 4-vinyl-benzoate, phenoxystyrene, p-vinyldiphenylsulfide, and p-vinylphenylphenyloxide; Acrylonitrile, methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isopropyl methacrylate, octyl methacrylate, methacrylonitrile, methyl α-chloro acrylate, ethyl α-epoxy acrylate, Methyl-α-acet aminoacrylate, butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, phenyl methacrylate, α-chloro acrylonitrile, N, N-dimethylacrylamide, N, Substituted acrylic monomers such as N-dibenzylacrylamide, N-butylacrylamide and methacrylformamide; Vinyl esters, vinyl ether vinyl ketones such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, isopropenyl acetate, vinyl formate, vinyl methoxyacetate, vinyl benzoate, vinyl iodide, vinyl toluene, vinyl naphthalene, Vinyl bromide, vinyl chloride, vinyl fluoride, vinylidene bromide, vinylidene chloride. 1-chloro-1-fluoro-ethylene, vinylidene-fluoride, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether. Vinyl-2-ethylhexyl ether. Vinyl phenyl ether, vinyl-2-methoxyethyl ether. Methoxy butadiene. Vinyl 2-butoxyethyl ether, 3,4-dihydro-1,2-pyran, 2-butoxy, 2'-vinyloxy diethyl ether, vinyl 2-ethylmercaptoethyl ether, vinyl methylketone, vinyl ethyl Ketones, vinyl phosphonates such as bis (β-chloroethyl) vinyl phosphonate, vinylphenylketone, vinylethyl sulfide, vinyl ethylsulfone, N-methyl-N-vinyl acetamide, N-vinyl-pyrrolidone, Vinyl imidazole, divinyl sulfide, divinyl sulfoxide, divinyl sulfone, sodium vinyl sulfonate, methyl vinyl sulfonate, N-vinyl pyrrole and the like; Dimethyl fumarate, dimethyl aliate, monomethyl itaconate. t-butylaminoethyl methacrylate, dimethylaminoethyl methacrylate, allyl alcohol, dichlorobutadiene, and vinyl pyridine. Known polymerizable monomers can be used as long as they meet the criteria for a stable dispersion of the present invention. The foregoing compounds are listed by way of example and do not limit the monomers suitable for use in the present invention.

In general, the object of the present invention is most easily achieved when the monomer used forms a soft polymer measured at a glass transition temperature below the service temperature. It is generally preferred that a dispersion stabilizer is present. Representative monomers are alkyl groups having four or more carbon atoms. Preferred are alkyl esters of acrylic acid and methacrylic acid containing 4 to 8 carbon atoms. Thus, butyl acrylate and 2-ethylhexyl acrylate are preferred. Other representative monomers include dienes such as butadiene and isoprene. Other useful monomers are vinylated polyoxyalkylenes. Copolymers of these monomers with other comonomers may also be used. Styrene and butadiene, for example, form well known elastomers. Most preferred are monomers which form elastomers.

Although monomers that form polymers with high softening temperatures can be used, the polymers have a less beneficial effect on the toughness of the cured dispersion. Such polymers can, if desired, be used, for example, as pigments or fillers. As mentioned above, it is generally preferred to use dispersion stabilizers. However, the composition of the present invention may be formed using a hard polymer having a glass transition temperature or crystal melting point above the curing temperature of the polyepoxide and the polymerization temperature of the polymer, in the absence of a stabilizer. Polyacrylonitrile is such a polymer.

Another aspect of the dispersed phase may include minor amounts of functional monomers having reactive groups other than the polymerizable double bonds. Examples of monomers having reactive radicals include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, 2-hydroxyethyl or propylacrylate, 2-hydroxyethylmethacrylate, tert-butyl-aminoethyl methacrylate. β-isocyanatoethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, glycol monoesters of itaconic acid, methyl monoesters of itaconic acid, acrylamide or substituted acrylamides, allyl alcohols. Maleic acid, fumaric acid and isopropenyl phenol. Such monomers may provide a site for subsequent crosslinking or binding to the epoxy matrix.

In addition, monomers containing one or more vinyl groups can be used at low concentrations to increase the molecular weight of the dispersed phase. Examples of such comonomers are divinylbenzene, allyl matacrylate or ethylene glycol dimeth acrylate.

The polymerization of ethylenically unsaturated monomers is induced and maintained under elevated temperature conditions by conventional free radical catalysts. The concentration of the catalyst can be varied from 0.001 to 10%, preferably from 0.2 to 1.0%, but a catalytically effective amount is satisfactory. Examples of catalysts are the free radical forms of known vinyl polymerization catalysts, such as hydrogen peroxide. Dibenzoyl peroxide, acetyl peroxide, benzoyl hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, lauroyl peroxide, butyryl peroxide, diisopropylbenzene hydroperoxide, cumene hydro Peroxide, Paramentane Hydroperoxide, Diacetyl Peroxide, Di-Alpha-Cyl Peroxide, Dipropyl Peroxide, Diisopropyl Peroxide, Isopropyl Tert-Butyl Peroxide, Butyl Tert-Butyl Peroxide, dilauroyl peroxide, difuroyl peroxide, ditriphenylmethyl peroxide, bis (p-ethoxybenzoyl) peroxide, p-monomethoxybenzoyl peroxide, rubrene peroxide, ascarridol, tertiary -Butyl peroxy-benzoate, diethylperoxyterephthalate, propylhydroperoxide, isopropyl hydroperoxide, n-butylhydroperoxide, 3-tert butylhydroperoxide , Cyclohexyl hydroperoxide, trans-decalin hydroperoxide, alpha-methylbenzylhydroperoxide, alpha-methyl-alpha-ethylbenzylhydroperoxide, tetralin hydroperoxide, triphenylmethylhydroperoxide, diphenyl Methylhydroperoxide, alpha-alpha'-azo-2-methylbutyronitrile, alpha, alpha'-2-methyl heptonitrile, 1,1'- azocyclohexane carbonitrile, dimethyl, alpha-, alpha'-azo Peroxides, persulfates, perborates, percarbonates and azo compounds, including isobutyrate, 4,4'-azo-4-cyanopentanoic acid, azobis isobutyronitrile, persuccinic acid and diisopropylperoxy dicarbonate Etc. Catalyst mixtures may also be used.

The polymerization of ethylenically unsaturated monomers can be carried out in the presence of an inert organic solvent. Examples of such solvents include toluene, benzene, acetonitrile, ethyl acetate, hexane, heptandicyclohexane, dioxane, acetone, N, N'-dimethyl, including those known in the art as suitable solvents for the polymerization of such monomers. Formamide, N, N-dimethylacetamide, halogenated solvents and 0-xylene. The only requirement in the selection of an inert solvent is that the solvent should not substantially interfere with the polymerization of the monomers. If a solvent is used, the solvent must be removed before curing.

The ethylenically unsaturated polymerization system may optionally contain a chain transfer agent in a small amount of 0.1 to 2% by weight based on the weight of the ethylenically unsaturated monomer in the dispersed phase. In the present invention, alkyl mercaptans containing 1 to 20 carbon atoms in the alkyl chain can be used. Representative mercaptans include ethyl mercaptan, propyl mercaptan, butyl mercaptan, hexyl mercaptan, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tetradecyl mercaptan, cetyl mercaptan and stearyl mercaptan. Other chain transfer agents, such as disulfide and halogenated compounds, in particular chlorinated, brominated or iodide compounds, may also be used.

The polymerization temperature used is above the softening point of the polyepoxide and generally above (but not necessarily) above the softening point of the particles in the dispersed phase.

As long as the polyepoxide is a continuous phase, the dispersed phase may be in an amount of 5 to 70% by weight, preferably 5 to 50% by weight of the total dispersion. The optimal concentration of the polymerizable dispersed phase may and should vary depending on the material used and the expected end use. Dispersions are usually prepared at a solid concentration at which the dispersion will be used. However, dispersions of high solids concentrations may be prepared and diluted to the desired solid concentration.

Dispersions are more readily prepared when dispersion stabilizers are included in the composition and have excellent stability and other properties. As a fundamental essential element, stabilizers can be any molecule containing two or more different segments, one of which is compatible with polyepoxide and the other with polymer particles. Most preferred stabilizers are reaction products of unsaturated monomers and vinylation adduct precursors, which may be the same monomers as the monomers in the dispersed phase.

The vinylation adduct is the reaction product of the functional monomer as described above with the polyepoxide. Preferably, the vinylation adduct is prepared by reacting a functional monomer as defined above having reactivity with an oxirane group. The reactive group can be, for example, a carboxyl, phenolic hydroxyl, thiophenolic isocyanato, or amino group. Methods of reacting these monomers with oxirane groups and the reactivity and useful reaction parameters are known and can be wisely selected by reference to literature and by simple preliminary experiments. Lee & Neville Handbook of Epoxy Resins, Mc-Graw-Hill, New York (1967) at Appendix 5-1 and the bibliograhy in Chapter 5, pages 39 to 40].

Stabilizers are most conveniently prepared in situ at the initial stage of preparing the dispersion. As an example, a small amount of unsaturated oxirane-active component relative to the polyepoxide amount is reacted with a certain amount of epoxy to produce a material having unsaturated groups and oxirane groups. This unsaturated group further reacts with other ethylenically unsaturated substances to produce a polymerizable stabilizer.

Alternatively, a stabilizer may be prepared separately and the preformed stabilizer may be added to the epoxy resin before or during the addition of the vinyl monomer and the polymerization reaction.

The reaction parameters for preparing the reaction product of the oxirane reactive compound and the oxirane-containing compound vary somewhat depending on the specific component used. Useful catalysts when using polyepoxides and unsaturated carboxylic acids include ethyltriphenyl phosphonium acetate, acetic acid complexes and other known onium compounds, tris (dimethyl), which are known to catalyze epoxy / carboxy reactions. Tertiary amines such as aminomethyl) phenol, triphenyl phosphine, and other compounds such as metal salts including chromium chloride and chromium acetate.

Typically, a polymerization inhibitor is added to the mixture to prevent premature polymerization before the epoxy / carboxy reaction is complete. Representative process inhibitors include 2,6-di-tert-butyl-4-methylphenol, p-methoxyphenol, hydroquinone, and tetrahydrothiazine, which are commercially available as ionol (trade name of Shell Company) antioxidants. have. Inhibitors are also commonly used for the storage of vinylated adducts.

The properties of the dispersion are influenced by various factors, including, for example, the identity of the components, the concentration and particle size of the dispersed phase, the hardness or softness of the dispersed phase particles, and the concentration of the dispersion stabilizer.

In most cases, in practical use, the stability and property improvement of the dispersion due to the dispersed phase is optimized when the particles are less than about 20 microns (20 μm).

The dispersion is solidified by curing the polyepoxide side. It is known that the choice of curing agent in polyepoxide curing can affect the rate of cure, exothermicity and final properties of the processed product. Curing agents and their effects are described in the literature. See Handbook of Epoxy Resins (Supra) in Chemical Reactions of Poly-mers Interscience Publishers New York Pages 912-926 (1967). Some of these effects are described in Modern Plastics Encyclopedia pages 33-34, (1982-1983). This document describes as follows.

Aliphatic polyamines and derivatives of these amines will cure the epoxy resin at room temperature. Some examples are diethylenetriamine, ketimine, cycloaliphatic amines and polyamides. Pot life, viscosity, toughness and thermal resistance can be influenced by the type of polyamine selected.

Aromatic amines such as 4,4'-methylenedianiline and meta-phenylenediamine are less reactive than aliphatic amines and typically need to be cured at elevated temperatures. These materials are systems and have a long pot life. It provides a polymer with better performance compared to aliphatic amines, especially at elevated temperatures.

Acid anhydrides are the second most commonly used curing agents. Some common acid anhydrides used are methyl tetrahydrophthalic anhydride and methyl hydride anhydride. Acid anhydride systems generally require curing at elevated temperatures, but offer advantages such as long pot life and excellent electrical properties.

The curing reaction by the catalytic curing agent proceeds by the single polymerization of epoxide groups. Representative catalysts include tertiary amines such as dicyandiamide, benzyldimethylamine and. Lewis acids or Lewis bases such as boron trifluoride mono ethylamine are included. These curing agents can provide long term room temperature pot life, rapid curing at elevated temperatures and excellent performance at elevated temperatures.

Melamine-. Phenol- and urea-formaldehyde resins are in the form of amino and phenoplast resin curing agents that crosslink through the hydroxyl groups of epoxy resins. These systems are cured at elevated temperatures to produce products with good chemical resistance.

In order to meet the requirements for molding and final cure product performance, the final epoxy resin / hardener system may contain primarily one or more additional materials such as accelerators, fillers, reinforcing agents and mono- or di-functional glycidyl ether diluents. Can be.

Cured products have improved toughness compared to the absence of a dispersed phase. In addition, the heat deflection temperature is improved over that seen by the product obtained by curing polyepoxides containing dissolved carboxylated rubbers such as carboxy-terminated diene elastomers.

The properties of the cured product are also influenced by the hardness of the dispersed polymer. In general, the best performance is obtained with polymer particles having a glass transition temperature below room temperature. Examples of such polymers are butyl acrylate. Homopolymers and copolymers of 2-ethylhexyl acrylate, butadiene, isoprene and vinylated polyalkylene oxide polymers.

The dispersions of the present invention are particularly well suited for a variety of high performance, engineering plastics applications where one or more of the physical properties of the polyepoxide has been a limiting factor. Especially these dispersions are solutions. It is useful as high concentration solids and powder coating compositions, fiber reinforced laminates and composites, casting and molding resins, and adhesives. Another field of application is the encapsulation of electrical members that are exposed to a wide range of temperature variations.

The concept of the invention is illustrated in the following examples. In the examples, all parts and percentages are by weight unless otherwise indicated.

In the example:

. 383에폭시 수지로 시판되고 있다.Resin A is a diglycidyl ether of bisphenol A having a viscosity at 25 ° C. of 9000 to 11,500 centipoises (9 and 11.5 Pa.s), and having an epoxide equivalent of 178 to 186 and the Dow Chemical Company ( DER by The Dow Chemical Com-pany

. 383 epoxy resin is commercially available.

. 331에폭시 수지로 시판되고 있다.Resin B is a diglycidyl ether of bisphenol A having a viscosity at 25 ° C. of 11,000 to 14,000 centipoises (11 and 14 Pa.s) and an epoxide equivalent of 182 to 190, and The Dow Chemical Company (The DER by Dow Chemical Com-pany

. 331 is marketed as an epoxy resin.

438에폭시 노보락으로 시판되고 있다.Resin C has formaldehyde, having an average number of phenols and therefore oxirane functionality of 3.6, an epoxide equivalent of 175 to 182, and a viscosity at 25 ° C. of 30,00 to 90,000 centipoises (30 and 90 Pa.s). As polyglycidyl ether of novolac of phenol, it is DEN by Dow Chemical Company

It is marketed as 438 epoxy Novolak.

438에폭시 노보락으로 시판되고 있다.Resin D has formphenol and phenol, having an average number of phenols, and thus an oxirane functionality of 2.2, an epoxide equivalent of 172 to 179, and a viscosity at 25 ° C. of between 1,400 and 2,000 centipoises (1.4 and 2 Pa.s). Is a polyglycidyl ether of Novolac, DEN by The Dow Chemical Company

It is marketed as 438 epoxy Novolak.

Resin E is tris (4-glycidylphenyl) methane sold by The Dow Chemical Company as XD-7342.00.

663u에폭시 수지로서 시판되고 있다.Resin F is a solid diglycidyl ether of bisphenol A whose softening temperature ranges from 88 ° C to 98 ° C, and whose molecular weight has been increased to epoxide equivalents 730 to 840 by bisphenol A, and DER by Dow Chemical Company.

It is marketed as 663u epoxy resin.

661 에폭시 수지로 시판되고 있다.Resin G is a solid diglycidyl ether of bisphenol A having a softening temperature in the range of 70 ° C. to 80 ° C., the molecular weight of which is increased to 475-575 by an epoxide equivalent by bisphenol A, and DER by Dow Chemical Company.

661 is marketed as an epoxy resin.

511로서 시판되고 있다.Resin H is a solid diglycidyl ether of bisphenol A having a softening temperature ranging from 68 ° C. to 80 ° C., a bromine content of 18 to 20% by weight, and an epoxide equivalent of 445 to 520, by Dow Chemical Company. DER

It is marketed as 511.

In the examples, the following test methods are used.

1. The particle size is measured directly from the scanning electron micrograph of the fracture surface.

2. The glass temperature is measured by the dynamic modulus at 0.1 Hz, carried out by the Rheometrics Mechanial Spectrometer Model RMS 605, and the reference is the maximum modulus loss temperature (G '').

3. Fracture energy (G, c) is measured using the double edge notch technique as defined in the literature ("ASTM Special Technical Bulletin # 410", ASTM, Philadelphia, Pa (1969), J.E. Defined by Srawley and W.F. As defined by Plane Strain Crack Toughness Testing of High Strength Metallic Materials by Brown, Jr.].

Example 1

Resin A (1000 g) is charged into a 2-liter three-necked round bottom flask equipped with dropwise, stirrer, condenser, thermocouple, and nitrogen sparge. The epoxy resin is heated to 120 ° C. with stirring and a solution of azobis isobutyronitrile (3 g), acrylonitrile (150 g) and resin A (350 g) is added over 1 hour. After further heating at 120 ° C. for 100 minutes, the volatiles are removed under vacuum. The final product is a stable viscous yellow dispersion of hard plastic particles in an uncured epoxy resin.

Comparative Example A

Resin B (1000 g) is charged to the reactor as described in Example 1. The resin is heated to 100 ° C. under an air blanket, and ethyltriphenyl phosphonium acetate acetic acid complex (0.5 g of 70% solution in methanol, also referred to as A-1 catalyst) and 10 g of acrylic acid are added. The temperature is then raised to 120 ° C. over 30 minutes. A solution of azobis isobutyronitrile (6 g), butyl acrylate (300 g) and resin B (200 g) is added over 80 minutes under a nitrogen blank kit. After further heating at 120 ° C. for 1 hour, the volatiles are removed under vacuum. Heating to 175 ° C. results in a clear solution: but cooling to room temperature gives an opaque dispersion of poly (butyl acrylate) in the epoxy resin. When the clear solution is cooled slowly, the cloud point is observed at 42 ° C.

[Comparative Example B]

Resin B (1000 g) is charged to a reactor as described in Example 1. The epoxy resin is heated to 100 ° C. while stirring in air and the A-1 catalyst is added. The mixture is heated to 120 ° C. with stirring for 1 hour. A solution of azobisisobutyronitrile (6 g), 2-ethylhexyl acrylate (300 g) and resin B (200 g) was then added over 1 hour under nitrogen spurge. After further heating at 120 ° C. for 1 hour, the volatiles are removed under vacuum. The product is poured into bottles and cooled.

After storing the dispersion overnight, the poly (2-ethylhexyl acrylate) particles solidify and aggregate to form a creamy phase on the surface of the epoxy resin. These results indicate that the dispersion is poor in stability.

Example 2

Resin B (1000 g) is charged to the reactor as described in Example 1. The resin is heated to 100 ° C. with stirring in air and A-1 catalyst (0.5 g) and acrylic acid (1 g) are added. The temperature is then raised to 120 ° C. over 1 hour. Under nitrogen blank kit, a solution of azobisisobutyronitrile (6 g), 2-ethylhexyl acrylate (300 g) and Resin B (200 g) is added over 75 minutes. After an additional hour of heating at 120 ° C., the volatiles are removed under vacuum.

After storing the dispersion overnight and comparing it with the product of Comparative Example B, it can be seen that improved stability is obtained by including the dispersion stabilizer in the preparation of the dispersion.

Heating to 247 ° C. leaves the dispersion of this example an opaque dispersion that is insoluble in the epoxy resin.

In the same way, if the amount of acrylic acid is changed to 5 g, 10 g, 15 g and 20 g, respectively, the stability increases with increasing acrylic acid.

Example 3

Resin B (1000 g) is charged to the reactor and esterified with acrylic acid (10 g) as described in Example 2. Azobisisobutyronitrile (6 g), 2-ethylhexyl acrylate (300 g), a solution of glycidyl methacrylate (1 g) and resin B (200 g) are added over 90 minutes. The modified epoxy resin is subsequently treated as described in Example 2. The cooled product is a stable dispersion upon cooling. Glycidyl methacrylate is included as a crosslinking agent for the particles and for bonding the particles to the epoxy matrix.

In the same manner, other dispersions are prepared by increasing the concentration of glycidyl methacrylate to 2 g, 5 g, and 10 g, respectively.

Example 4

The method is essentially the example using 10 g acrylic acid for esterification, except that various concentrations (3 g, 1.5 g, and 0.75 g) of azobisisobutyronitrile (AIBN) are used as free radical initiators. Same method as described in 2.

Example 5

Resin D (1200 g) is charged to a reactor as described in Example 1 and heated to 100 ° C. A-1 catalyst (0.5 g) was added (methacrylic acid was not added). The resin is heated to 120 ° C. in 30 minutes. A solution of azobisisobutyronitrile (6 g), 2-ethylhexyl acrylate (300 g) and glycidyl methacrylate (10 g) is added over 60 minutes under a nitrogen blank kit. After an additional 60 minutes at 120 ° C., the volatiles are removed under vacuum. The final product is a dispersion with large particle size.

In a similar manner, Resin D (1000 g) is charged to a reactor as described in Example 1 and heated to 100 ° C. A-1 catalyst (0.5 g) and methacrylic acid (MAA) (5.0 g) are added with stirring and the temperature is raised to 120 ° C. over 30 minutes. A solution of azobisisobutyronitrile (6 g), 2-ethylhexyl acrylate (300 g), glycidyl methacrylate (10 g) and resin D (200 g) was added over 60 minutes under a nitrogen blank kit. After an additional 60 minutes of holding at a temperature of 120 ° C., the volatiles are removed under vacuum. The final product is a stable dispersion with a small particle size.

In the same way, further dispersions are prepared using higher amounts (10 g and 15 g) of methacrylic acid.

Example 6

(a) Resin A (1000 g) is placed in a reactor as described in Example 1. The resin is esterified with methacrylic acid (5 g) as described in Example 5. A solution of azobisisobutyronitrile (3 g), 2-ethylhexyl acrylate (300 g), glycidyl methacrylate (10 g), divinylbenzene (DVB) (0.5 g) and resin A under a nitrogen blank kit Add over 60 minutes. After an additional 1 hour of heating at 120 ° C., the volatiles are removed under vacuum. The final product is a stable dispersion with a Brookfield viscosity of 23,600 centipoise (23.6 Pa.s).

(b) In the same way, the amount of divinylbenzene is changed. The product is also prepared in Resin B. Divinylbenzene is used to increase the molecular weight of the polymer.

Example 7

Resin A (1100 g) is charged to the reactor as described in Example 1. The resin is esterified with methacrylic acid (15 g) as described in Example 5. Under nitrogen blank kit, azobisisobutyronitrile (2.7 g), 2-ethylhexyl acrylate (2-EHA) (133 g), glycidyl methacrylate (2.2 g) and Resin A (100 g) were added 60 Apply over minutes. The vinyl polymerization reaction is carried out as in Example 3. The final product is a stable dispersion having a solids content of 10% based on the weight of poly (2-ethylhexylacrylate) and a Brookfield viscosity of 33,400 centipoise (33.4 Pa · s).

In a similar manner, additional stable products having a solids content of 15 to 50 percent are prepared.

Example 8

Resin A (1000 g) is charged to the reactor as described in Example 1. The resin is heated to 100 ° C. under an air blank kit and A-1 catalyst (0.5 g) and methacrylic acid (MMA) (1 g) are added. The temperature is raised to 120 ° C. over 30 minutes. Azobisisobutyronitrile (1 g), 2-ethylhexyl acrylate (300 g) under a nitrogen blank kit. A solution of glycidyl methacrylate (10 g) and resin A (200 g) is added over 60 minutes. After an additional hour of heating at 120 ° C., the volatiles are removed under vacuum. The product is a dispersion with better stability compared to Comparative Example B but with a tendency to cream over time.

In the same way, dispersions are prepared using 5.0,7.0,10.0,15.0 and 20.0 g of methacrylic acid. Increasing the amount of methacrylic acid results in improved stability and smaller particle size. As the amount of methacrylic acid increases, the viscosity of the dispersion also increases.

In addition to the dispersion prepared in Example 8 using 10.0 g of methacrylic acid, the same preparation conditions and the same amount of the resins A and A-1 catalysts. Azobisisobutyronitrile, glycidyl methacrylate, and alkyl acrylate or methacrylate esters are further used to prepare nine solutions and dispersions. Esters used are ethyl acrylate, n-propyl acrylate, secondary-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-octyl acrylate, isodecyl acrylate, isodecyl methacrylate and Lauryl methacrylate. The eleventh sample (Sam-ple) was prepared using n-butyl acrylate under the same process conditions and ester as in Example 8. Methacrylic acid, an A-1 catalyst or glycidyl methacrylate are not used. Resin A, n-butyl acrylate and azobisisobutyronitrile are used in the same amount.

For these eleven samples, it is observed whether the organic polymer is soluble in resin A at 175 ° C and room temperature (25 ° C). Cloud points are recorded for samples made from n-butyl acrylate, n-pentyl acrylate and n-hexyl acrylate. Samples prepared from 2-ethylhexyl acrylate do not dissolve in the polyepoxide even when heated to 247 ° C.

Glass transition temperature (T _g ), particle size and toughness (G _1c ) are measured for various cured dispersions. The cured dispersion is prepared as follows. The resin or dispersion is heated to 60 ° C. A stoichiometric amount of triethylenetetramine is added at room temperature and stirred rapidly. The heated mixture is degassed by evacuating the mixture until the rapid release of the gas stops. This usually takes about two minutes. The degassed mixture is then poured into a suitable mold and cured for 16 to 20 hours under ambient conditions. Post curing is carried out at 150 ° C. for 1 hour.

The hardened casting is then processed to the appropriate size and shape for testing. Various samples prepared from Examples 2-8 were tested according to the method described above to obtain the following results. The resin used in Comparative Examples D and E is Resin A.

* Weight% based on resin and rubber: CTBN is carboxyl terminated butadiene-acrylonitrile rubber.

The data above indicate that the stable dispersions of the present invention generally have improved toughness (high G _1c ) without significant loss of T _g .

Example 9

Resin B (1000 g) is charged to a reactor as described in Example 1. The resin is heated to 100 ° C. under an air blank kit and Ionol ^* antioxidant (1 g), isopropenyl phenol (5 g) and A-1 catalyst (0.5 g) are added with stirring. Raise to 120 ° C. over 35 minutes. Under nitrogen blank kit, a solution of azobisisobutyronitrile (6 g), 2-ethylhexyl acrylate (300 g) and resin B (200 g) is added over 75 minutes. After an additional hour of heating at 120 ° C., the volatiles are removed under vacuum. The final product is a stable dispersion with better stability than the product produced without the use of vinylation adducts.

Example 10

Suzy. (600 g) is charged to the reactor as described in Example 1. The resin is heated to 100 ° C. under an air blank kit and added while stirring A-1 catalyst (0.5 g) and methacrylic acid (5.0 g). The temperature is then raised to 120 ° C. over 30 minutes. A solution of azobisisobutyronitrile (2 g), 2-ethylhexyl acrylate (200 g) glycidyl methacrylate (10 g) and resin A (200 g) was added over 45 minutes under a nitrogen blank kit. After 30 minutes of further heating at 120 ° C., the volatiles are removed under vacuum. The final product is a semi-solid, amber, stable dispersion.

In the same way, 10 g and the amount of methacrylic acid. Change to 15 g: Particle size decreases with increasing amount of methacrylic acid.

Example 11

Resin C (1200 g) is charged to a reactor as described in Example 1. The resin is heated to 100 ° C. under an air blank kit and added while stirring A-1 catalyst (0.5 g) and methacrylic acid (2.5 g). The temperature is raised to 120 ° C. over 30 minutes and maintained for a total of 1 hour. A solution of azobisisobutyronitrile (3 g), 2-ethylhexyl acrylate (300 g) and glycidyl methacrylate (10 g) is added over 60 minutes under a nitrogen blank kit. After 30 minutes of further heating at 120 ° C., the volatiles are removed under vacuum. The final product is a semi solid stable dispersion.

In the same way, the amount of methacrylic acid is changed to 10 g, 15 g and 20 g; As the amount of methacrylic acid increases, the particle size decreases.

[Examples 12 and 13]

Resin F (1200 g) was filled into the reactor as described in Example 1. The resin is heated to 150 ° C. under an air blank kit and added while stirring A-1 catalyst (0.5 g) and methacrylic acid (2.5 g). The temperature is held at 150 ° C. for another 60 minutes. 2-3-butylazo-2-cyanobutane (3 g, Luazo ^* -82 catalyst under a nitrogen blank kit. Trademark of Lucidol Div. Of Pennwalt Corp.). 2-ethylhexyl acrylate (300 g) and glycidyl methacrylate (10 g) are added over 60 minutes. After further heating at 120 ° C. for 1 hour, volatiles are removed under vacuum. The final product is a stable dispersion in solid resin.

In the same manner, resin F is replaced with resin H to prepare a dispersion of brominated resin.

Example 14

Resin B (1000 g) is charged to a reactor as described in Example 1. The epoxy resin is heated to 100 ° C. and added while mixing isocyanatoethyl methacrylate (10 g) and dibutyl tin dilaurate catalyst (0.1 g). The temperature is raised to 110 ° C. and maintained for a total of 1 hour. Subsequently, azobisisobutyronitrile (3 g) 2-ethylhexyl acrylate (300 g), glycidyl methacrylate (10 g), methacrylic acid (10 g) and resin B (200 g solution) were added under nitrogen atmosphere for 1 hour. After 30 minutes of further heating, the product is evaporated under vacuum The product is a stable dispersion A-1 catalyst (0.5 g) is added to half of this dispersion The temperature is maintained at 110 ° C. for an additional 75 minutes The purpose of this reaction is to catalyze the reaction of methacrylic acid groups with glycidyl methacrylate to provide crosslinked particles.

Example 15

A. Preparation of Resin A / Methacrylic Acid Master Batch

Resin A (924 g) is charged to the reactor as described in Example 1. The epoxy resin is heated to 100 ° C. and methacrylic acid (43.04 g) and A-1 catalyst (0.25 g) are added. The temperature is maintained at 100 ° C. and the reaction rate is traced by titration of excess acid. After 3 hours the reaction is 99 percent complete. The product is the clear viscous partial ester of resin A. This product is an example of a vinylation adduct.

B. Preparation of Dispersion in Resin A

Resin A (885 g) and the partial methacrylic acid ester of Resin A (115 g) described above are charged to a reactor as described in Example 1.

The contents were heated to 120 ° C. under a nitrogen atmosphere and a solution of azobisisobutyronitrile (3 g), 2-ethylhexyl acrylate (300 g), glycidyl methacrylate (10 g) and Resin A (200 g) was 45 minutes. Apply over. After 30 more minutes of heating the product is evaporated under vacuum. The final product is a stable dispersion.

Example 16

A. Preparation of Resin G / Acrylic Acid Master Batch

Resin G (1050 g) is charged to the reactor as described in Example 1. The epoxy resin is heated to 120 ° C. and acrylic acid (15 g), ionol ^* antioxidant (1 g) and A-1 catalyst (0.5 g) are added. After the temperature is held at 120 ° C. for another 30 minutes, the product is poured into a metal tray and cooled. The final product is a solid, clear partial ester which is ground and soaked in a bottle. The product is an example of a vinylated adduct.

B. Preparation of Dispersion in Resin B

Resin B (700 g), and the partial acrylic acid ester of Resin G described above, are charged to a reactor as described in Example 1. The contents were heated to 120 ° C. under a nitrogen atmosphere and a solution of azobisisobutyronitrile (6 g), 2-ethylhexyl acrylate (300 g), glycidyl methacrylate (10 g) and resin A (200 g) was mixed. Apply over 45 minutes. After another hour of heating at 120 ° C. the product is evaporated under vacuum. The final product is a stable dispersion. The product has a smaller particle size than when the same amount of acrylic acid was used to cap low molecular weight resin B.

In the same manner, other dispersions are prepared in which the initial amounts of resin B and acrylic acid-capped resin G are varied, resin B800g and acrylic acid-capped resin G200g and resin B900g and acrylic acid-encapsulated resin G100g. The portion size increases as the amount of acrylic acid-capsulated resin G is reduced.

Example 17

A. Preparation of Resin A / Methacrylic Acid Master Batch

Resin A (1848 g) and ionol ^* antioxidant (0.2 g) are charged to the reactor as described in Example 1. The epoxy resin is esterified with methacrylic acid (86 g) as described in step A of Example 16.

B. Preparation of Polymer Epoxy Dispersions

Resin A (200 g) is charged to a reactor as described in Example 1. Heat the epoxy resin to 110 ° C. and mix a solution of azobisisobutyronitrile (1.25 g), 2-ethylhexyl acrylate (250 g) and the partial methacrylic ester of resin A (800 g) described above under a nitrogen blank kit. Apply over 1 hour. After further heating for 5 hours and 15 minutes, the product is evaporated under vacuum. The product is a cloudy, viscous liquid polymeric dispersion.

C. Preparation of Dispersion in Resin A.

Resin A (760 g) and the dispersion (300 g) in step B described above are charged to a reactor as described in Example 1. The contents were heated to 105 ° C. under a nitrogen atmosphere and a solution of azobisisobutyronitrileethyl (1.25 g), 2-ethylhexyl acrylate (240 g), glycidyl methacrylate (10 g) and resin A (200 g) was prepared. Apply over an hour. After 30 minutes of further heating at 105 ° C. the product is evaporated under vacuum. The final product is a stable dispersion.

Claims (9)

The organic polymer, the polymerization product of ethylenically unsaturated monomers, forms an insoluble dispersed phase having a particle size of less than 20 μm in a polyepoxide in continuous phase at a temperature of at least 60 ° C., where the dispersed phase is from 5 to 70 weight of the total dispersion. A stable dispersion of organic polymer in polyepoxide, characterized in that it is present in an amount of%. The dispersion according to claim 1, wherein the polymerization product is formed by in-situ polymerization of ethylenically unsaturated monomers. 3. The dispersion according to claim 2, wherein the ethylenically unsaturated monomer is an alkyl acrylate or alkylmethacrylate, wherein the alkyl group has at least 4 carbon atoms. Consisting of an organic polymer which is a polymerization product of ethylenically unsaturated monomer as a dispersed phase, a polyepoxide as a continuous phase, and a dispersion stabilizer, wherein the dispersed phase is present in an amount of 5 to 70% by weight of the total dispersion and is less than 20 μm. A stable dispersion, characterized in that it has a particle size and remains insoluble in the polyepoxide continuous phase at a temperature of at least 60 ° C. 5. A dispersion according to claim 4, wherein the dispersion stabilizer is a polymer of vinylated adducts of at least one vinyl monomer and polyepoxide. The dispersion according to claim 5, wherein the vinylated adduct of the polyepoxide is a reaction product of the functional monomer and the polyepoxide. (1) reacting a small amount of functional monomer with a polyepoxide to produce a vinylated adduct, (2) reacting the vinylated adduct with an ethylenically unsaturated monomer to produce a dispersion stabilizer, and then (3) dispersing stability A process for the preparation of a stable dispersion as defined in claim 1 comprising the step of preparing a dispersion of an organic polymer of ethylenically unsaturated monomer in a polyepoxide in the presence of a topical agent. Method according to claim 7, characterized in that steps (2) and (3) are carried out simultaneously. 8. The process of claim 7, wherein a dispersion stabilizer is prepared separately and added to the polyepoxide before or during the addition of ethylenically unsaturated monomers and the polymerization reaction.