GB1567375A

GB1567375A - Blends fo thermosetting resins with ethylene copolymers

Info

Publication number: GB1567375A
Application number: GB1326277A
Authority: GB
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1977-03-29
Filing date: 1977-03-29
Publication date: 1980-05-14

Description

(54) BLENDS OF THERMOSETTING RESINS WITH ETHYLENE COPOLYMERS (71) We, E.I. DU PONT DE NEMOURS AND COMPANY a Corporation organised and existing under the laws of the State of Delaware, United States of America, of Wilmington, Delaware, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to curable blends including ethylene copolymers, to shaped articles formed therefrom and to a method of producing such shaped articles. More particularly this invention relates to curable blends of thermosetting resins with copolymers of ethylene, a flexibilizing monomer, a third monomer which contains epoxy side groups, and optionally carbon monoxide.This invention also relates to shaped articles, such as films, fibers and foams, formed from such blends.

Ethylene polymers are characterized by a low polarity and low reactivity. They are like waxes in this respect, having a low dielectric constant and being soluble in hot oils, hot wax and hot hydrocarbons, they also are well known to be very inert. For some uses it is desirable to modify the ethylene polymers to make then flexible, to impart more polarity to the polymers, and to be able to use them in reaction with other resins. A small degree of polarity and a certain amount of flexibility can be imparted to an ethylene polymer by incorporation therein of unsaturatec organic esters, such as vinyl acetate or acrylates. However, to obtain a high degree of polarity high levels of ester are required which in turn adversely affects the inherit advantage of the long ethylene chain, e.g. low cost, good low temperature behavior, etc.Thus it is desirable to increase the polarity of an ethylene copolymer while retaining the hydrocarbon chains as the major feature of the polymer. Ethylene copolymers, however, modified to be more flexible and more polar may still be relatively unreactive.

The art regarding thermosetting resins and especially blends with other polymers will now be considered. Commercially available thermosetting resins such as phenolics, epoxys, etc, have been found to be useful because of the retention of their performance at elevated temperatures. This retention of performance is associated with the cross-linking or curing action inherent in the structure of the thermosetting resins utilized. However, this retention of high temperature performance is accompanied by high stiffness and brittleness making it desirable to lower the stiffness of such material or if some stiffness is desired by providing a higher degree of toughness. The obvious solutions, to blend a flexible polymer into the thermosetting resin, has not been successful to the best of our knowledge.Molecular compatibility has not been achieved; the desirable properties of the thermoset are lost.

According to the present invention there is provided a curable blend comprising 99 to 1 percent by weight of an organic thermosetting resin selected from phenolic resins, e.g. phenol formaldehyde resins; epoxy resins, and melamine-formaldehyde resins and 1 to 99 percent by weight of an ethylene copolymer con siat,ng essentially of, by weight, (a) 40 to 90 percent ethylene; (b) 0 to 20 percent carbon monoxide; (c) 5 to 40 percent of a monomer copolymerizable therewith to provide flexible polymers, said monomer being an unsaturated mono- or dicarboxylic acid of 3 to 20 carbon atoms, an ester of such an insaturated monoor dicarboxylic acids, a vinyl ester of a saturated carboxylic acid where the acid group has 1 to 18 carbon atoms, a vinyl alkyl ether where the alkyl group has 1 to 18 carbon atoms, acrylonitrile, methacrylonitrile, an alpha-olefin of 3 to 20 carbon atoms, norbornene or a vinyl aromatic compound; and (d) 0.2 to 15 percent of an ethylenically unsaturated monomer of 4 to 21 carbon atoms containing an epoxy group; with the proviso that the organic thermosetting resin is a phenolic resin or a melamineformaldehyde resin when the ethylene copolymer is a terpolymer consisting essentially of monomers (a), (c) and (d).

The present invention also provides shaped articles obtained by moulding a curable blend of the invention and heating to cure the thermosetting resin. In particular, the invention provides a method of producing a shaped article which comprises dispersing (a) 5 to 95 percent by weight of an ethylene copolymer as defined above in 95 to 5 percent by weight of a thermosetting resin in which said copolymer is soluble.

said thermosetting resin being selected from phenolic resins, epoxy resins, and melamineformaldehyde resins, with the proviso that the resin is a phenolic resin or a melamineformaldehyde resin when the ethylene copolymer is a terpolymer consisting essentially of monomers (a), (c) and (d); (b) molding the resulting blend; and (c) maintaining the molded blend at an elevated temperature until a crosslinked resin is formed, said ethylene copolymer remaining substantially dispersed in the cured thermosetting resin.

The term "phenolic resins" is meant to in clude thermosetting phenol-aldehyde resin, e.g., those made from phenol, cresol, e.g., m-pcresol mixture, p-cresol or cresylic acid resorcinol with aldehydes such as formaldehyde and furfural. The one-step type (resoles) or the two-step type (novolaks) are useful (U.S.P.

3,438,931). Also useful are phenolformaldehyde resins modified with alkyl phenols (e.g., cresols), polyhydric phenols (e.g., resorcinol, hydroquinone, etc.), or polyphenols (e.g., Bisphenol A). Preferred blends contain copolymers of (a) ethylene, (b) carbon monoxide, (c) a vinyl ester of a saturated carboxylic acid wherein the acid group has 1 to 18 carbon atoms, in particular a vinyl alkanoate such as vinyl acetate, vinyl propionate, vinyl butyrate; an ester of an unsaturated mono- or dicarboxylic acid of 3 to 20 carbon atoms, in particular an alkyl acrylate or alkyl methacrylate wherein alkyl is from 1 to 20 carbon atoms such as methyl acrylate, ethyl acrylate, or methyl methacrylate, or dibutyl maleate or dimethyl fumarate; or a vinyl alkyl ether such as vinyl methyl ether or vinyl butyl ether; and (d) an epoxy ester of a copolymerizable unsaturated organic acid, an epoxy ether of a vinyl ether or an allyl ether, or a mono-epoxy substituted di-olefin of 4 to 12 carbon atoms.

A specific preferred blend contains a copolymer of (a) ethylene, (b) carbon monoxide, (c) vinyl acetate, and (d) glycidyl acrylate or methacrylate.

Another specific preferred blend contains a copolymer of (a) ethylene, (c) vinyl acetate and (d) glycidyl acrylate or methacrylate with no (b) carbon monoxide.

The copolymers in the preferred blends contain the following weight percent of components (a) to (d): (a) 45 to 90, more preferably, 50 to 70.

(b) 0 to 15, more preferably, 0 to 3 or 10 to 15.

(c) 10 to 33, more preferably, 20 to 30.

(d) 0.4 to 9, more preferably, 1.5 to 1.6.

The copolymers normally have a melt index within the range of 0.1 to 3,000, preferably 5 to 500.

Copolymers containing 2 to 20 weight percent carbon monoxide (b) which can be used in the blends of the present invention and described and claimed in Application No.

13261/77 Serial No. 1 567 374).

The above curable blends may be formed into a sheet, a block for molding purposes, or a fiber before the blends are cured. The curable blends can be a solid form which is grindable into a powder and then formed into a molding or shaped article, into a film, a coating, or into a fiber before curing.

Cured compositions, in the forms described above, result from heating, e.g., oven, mold, etc., the above curable blends.

The poor performance of thermosetting resins such as phenolics is generally exhibited by a high degree of brittleness. This is usually exhibited either by a brittle failure from a high speed impact, or by a brittle failure at low strains under a slow speed test such as bending.

In actual use, this may occur with the drppping of a molded object such as a bottle cap to the floor, the twisting of a toy, or even by slight thermal strains. The latter occur regularly on a molded piece with metal inserts which might be used under the hood of a car.

In order to demonstrate the present invention it is necessary to reduce the qualitative brittlene problems described above to quantitative laboratory measurements. In slow-rate flexural measurements we have found that conventional filled phenolics and epoxies fail when the strain on the sample is as little as about 1%. For practical purposes, raising the level of strain to failure by 2-3 fold; i.e., to 2-3% is a major ac complishment.

For impact measurements, the notched Izod test has been chosen. In this test, the ability of the molded piece to absorb impact energy is measured. Conventional filled phenolic molding resins show very low values, say 0.1 to 0.3 ft pounds per inch of notch, when the sample is broken. This value depends upon the type or combination of filler. It can be increased by modifying the structure with more expensive phenollcs, or by using fillers such as long glass fibers or cotton floc. Resins using these types of fillers are provided on a commercial basis, but are not used extensively because of the high cost of making the blend, and difficulties in actual use of the commercial product.

Thus, there has continued to be a need for a resin modifier which can be added to the thermosetting molding compound to increase its toughness.

This invention requires and depends upon the compatibility of the modifying resin with the thermosetting resin. There are two types of compatibility involved in this invention and at two stages in use, before and after curing.

One type of compatibility is the most common one, where the blends of the two resins are completely miscible on a molecular scale, and give clear films. This invention encompasses that type of compatibility as described herein.

This invention also requires and depends on a second and lower degree of compatibility which is also important. It is often possible to blend two resins and find them to appear to be incompatible as evidenced by the two-phase opacity of a molded film. Nevertheless we find that the blend is strong and tough; the two resins are functionally compatible. This functional compatibility occurs because the two phases are interdependent and not pure phases of the starting resins. Each phase contains a small amount of the other resin. In fact in molten two-phase blends of this type there is an equilibrium condition with a constant migration of molecules across the phase boundaries. One theory suggests that the cooled sample has some molecules trapped part way across the boundary and thereby imparting the improved mechanical performance.

Most polymerlpolymer blends do not exhibit this functional compatibility. Blends such as polyvinyl chloride with polystyrene seem to show no molecular interdependence in the melt and do in fact show extremely friable, brittle opaque films. This behaviour is the general case, It is part of this invention to tailor the structure of the modifying resin to the structure of the uncured thermosetting resin to give good melt working characteristics and functional compatibility.

It is also essential to this invention that the compatibility not be destroyed by the curing process. It is possible to devise a polymerresin blend which is completely compatible (clear) before curing, but which becomes twophase (opaque) after curing. The molecular motion which occurs during the curing process enables the resin molecules to achieve the best position for the chemical curing, and at the same time rejects the modifier molecules into a separate, second phase.

An essential part of this invention is the incorporation in the modifier molecule of a site which cocures with thermosetting resin. Such a site is essential for both the completely compatible blends and the functionally compatible blends of the present invention.

The copolymers in the blends of this invention consist essentially of the above described amounts of ethylene, carbon monoxide and monomers (c) and (d) which are copolymerizable ethylenically unsaturated organic compounds. Monomers (c) are selected from the class consisting of unsaturated mono- or dicarboxylic acids of 3 to 20 carbon atoms, esters of such unsaturated mono- or dicarboxylic acids, vinyl esters of saturated carboxylic acids where the acid group has 1 to 18 carbon atoms, vinyl alkyl ethers where the alkyl group has 1 to 18 carbon atoms, acrylonitrile, methacrylonitrile, alpha-olefins of 3 to 20 carbon atoms, norbornene, and vinyl aromatic compounds. Vinyl acetate is preferred monomer (c).

Monomers (d) are ethylenically unsaturated monomers of 4 to 21 carbon atoms which contain an epoxy group. Such monomers are taken from the class consisting of epoxy esters of copolymerizable unsaturated organic acids, e.g., acrylic or methacrylic and more particularly glycidyl acrylate or glycidyl methacrylate; the epoxy ethers of vinyl ethers and allyl ethers, e.g., glycidyl vinyl ether, vinyl cyclohexane monoxide, etc., or the mono-epoxy substituted di-olefins of 4 to 12 carbon atoms. Glycidyl acrylate and methacrylate are preferred monomers (d).

In preparing the copolymers of the present invention, commercially available ethylene, carbon monoxide and unsaturated monomers (c) and (d) of about 100 percent purity are used initially and in supplying continuous makeup for the polymerization feed stream. The reactor vessel used is capable of withstanding high pressures and temperatures, and is equipped with a high speed motor-driven stirrer and pressure relief valves, as well as jacketed walls for circulating heating or cooling fluids in order to control temperature. Carbon monoxide and other monomers are pumped into the ethylene monomer feed stream at the pressure of the reactor, and then the mixture of monomers is pumped at reactor pressure into the reactor, either together or separately. Catalyst, as necessary, is pumped into the reactor through a separate feed line.

A mixture of copolymer and monomer exits the reactor, and the pressure is reduced as the mixture flows into a separator. Monomers leave the separator and are either destroyed or pumped for recycle to the reactor together with make-up monomers. Molten copolymer leaves the separator in a stream, from which it is cooled and further processed, e.g., the copolymer may be cut into suitable sized particles and put into suitable containers for shipping.

The flow of ethylene, carbon monoxide, monomers (c) and (d) and catalyst into the reactor is carefully controlled so that they enter the reactor in constant continuous molar ratios and at the same continuous rate at which product and unreacted monomers are discharged from the reactor. The rates and molar ratios are adjusted so as to provide in the product copolymer, by weight, 40 to 90 percent ethylene, 0 to 20 percent carbon monoxide, 5 to 40 percent of monomer (c) and 0.2 to 15 percent monomer (d). Effective stirring, usually at a rate of at least 0.25 horsepower per gallon of reactor volume, is provided in order to keep the reacting monomers in intimate admixture throughout the reactor.

The reactor temperature should be at least 140"C. It is preferred that the reactor temperature be maintained within the range of about 155-300"C., and that the reactor pressure be maintained within the range of 500060,000 psi, preferably about 20,000-35,000 psi.

It is important in preparing the copolymers of the present invention that the contents of the reactor be kept uniform with respect to the weight ratios of ethylene, carbon monoxide and monomers (c) and (d) to produce the solid copolymers of the present invention. None of the monomers should be depleted so that not less than all of the monomers are reacting.

Since the various monomers react at different rates, a larger percentage of faster reacting monomers will react in a given time. Consequently, the ratio of feed rate for the monomers will be different from the desired ratio of those monomers in the copolymer produced.

Thus, carbon monoxide reacts at a rate about five times that of ethylene, so that when 10 percent of the ethylene present has been incorporated in polymer, about 50 percent of the carbon monoxide present is in polymer.

Conditions required to produce specific copolymers vary, depending on the reactivity of monomers (c) and (d), e.g., vinyl acetate reacts at about the same rate as does ethylene, whereas other monomers such as methyl methacrylate react about as fast as or faster than carbon monoxide. The epoxy-containing monomers (d) may react at rates which vary between the speed of reaction of ethylene and carbon monoxide.

The free-radical polymerization catalyst employed in the process can be any of those commonly used in the polymerization of ethylene, such as the peroxides, the peresters, the azo compounds, or the percarbonates. Seleted compounds within these groups are dilauroyl peroxide, ditertiary butyl peroxide, tertiary butyl perisobutyrate, tertiary butyl peracetate, a, a-azobisisobutyronitrile and other compounds of comparable free-radical activity. Usually the catalyst will be dissolved in a suitable inert organic liquid solvent such as benzene, kerosene, mineral oil or mixtures of solvents, The usual catalyst level is used, i.e., about 25 to 2500 ppm., preferably about 75 to 500 ppm, based on the weight of the monomers fed to the reac tors.

For the purpose of this invention it is desirable to understand the nature of blends of two molten polymers as the blending is affected by the molecular nature of high polymers. Thermo setting resins, such as phenolic resins, are produced as medium molecular weight polymers for processing into the desired form prior to the curing step. (These resins are not formable after curing). When one melts an uncured thermosetting resin and attempts to blend in a molten thermoplastic resin, the dispersion of thi thermoplastic copolymer is accomplished through a shearing of the molten thermosetting resin. In order to disperse the molten thermoplastic polymer into very small droplets there must be an interaction between the two molten polymers at their mutual interface, so that the shear forces in the molten thermosetting resin can act on the molten thermoplastic resins.This is accomplished when each polymer is partially soluble in the other. Otherwise the thermoplastic resin remains in the liquid as relatively large particles. The first requirement in this invention, then, is the discovery of the molecular structure which will provide a thermoplastic resin which is partially soluble in the liquid thermosettable resin.

The curing of a thermosetting resin occurs by the chemical linking of the thermosettable molecules through sites which occur on the average at more than two per molecule. When a nonreactive thermoplastic polymer is dissolved in the thermosetting resin, these thermosettable molecules move around rapidly during curing to exclude the thermoplastic polymer. The thermoplastic polymer is thereby forced out of the solidifying thermosetting composition.

As a result a two phase system is formed. One phase is the rigid brittle thermosetting matrix.

The second phase consists of the previously dissolved thermoplastic resin. The second requirement of this invention, then, is the incorporation of a reactive epoxy group in the thermoplastic copolymer which will provide a site through which the thermoplastic copolymer participates in the curing step. The thermoplastic copolymer is thereby intimately bound into the matrix of the cured thermosetting resin.

To summarize, the thermoplastic resin is intended to act as a useful modifier for the thermosetting resin. To be effective, it must be partially dispersed on a molecular scale, i.e., partially dissolved in the thermosetting resin before the cure; and it must remain substantially dispersed in the thermosetting resin after cure.

Another point which must be recognised is that there are two useful degrees of dispersion in terms of the description above. One is when the thermoplastic resin is so well dispersed, after cure, that the resultant blend is clear. A molded cured film from such a blend is more flexible than the unmodified thermosetting resin, It has a modest and useful degree of elongation before the sample fails; but when the sample does fail, it fails in a brittle fashion without much absorption of energy. It is well known in the art, however, that rubbery impact modifiers for rigid thermoplastic resins should be finely dispersed as a separate phase which is intimately bonded to the rigid phase.

Thermosetting resins, on the other hand, are much more difficult to toughen. The present invention embodies the discovery of adjusting the structure of the copolymers to achieve the same type of effect; i.e., the copolymers of the present invention can be adjusted so they dissolve only partially in the uncured thermoses.

ting resin. Then, after curing, the tiny agglomerates of the thermoplastic resin of the present invention are capable of absorbing impact energy, but do so, in fact, only because they are also bonded through reactive sites to the molecules of the cured thermosetting matrix.

The copolymers described above can be used to make curable blends with effective amounts of solid organic thermosetting resins taken from the class consisting of phenolic resins, e.g., phenol formaldehyde resins. epoxy resins, and melamine formaldehyde resins with the proviso that the thermosetting resin is a phenolic resin or a melamine formaldehyde resin when the ethylene polymer is a terpolymer consisting essentially of monomers (a), (c) and (d). The term "phenolic resins is meant to include thermosetting phenol-aldehyde resins, e.g., those made from phenol, cresol, e.g., mp-cresol mixture, p-cresol or cresylic acid, resorcinol with aldehydes such as formaldehyde and furfural. The one-step type (resoles) or the two-step type (novalaks) are useful ( U.S.P.

3,438,931). Also useful are phenol-formaldehyde resins modified with alkyl phenols (e.g., cresols).

polyhydric phenols (e.g., resorcinol, hydroquinone, etc.), or polyphenols (e.g., Bisphenol A).

These curable blends may comprise I to 99 percent of the above copolymers and 1 to 99 percent of the thermosetting resins. Preferably the copolymer is present in the blend in a percent of 5 to 95 and the thermosetting resin is present in the blend in a percent of 5 to 95. A particularly preferred percentage range for the copolymer is 10 to 50 percent, and the thermosetting resin is 90 to 50 percent.

The curable blends described herein may be filled with the conventional fillers used in thermosetting systems. These fillers may be wood flour, asbestos, silica, fiberglass, cotton flock, mica, macerated fabric and cord, rag, carbon black, or metal, such as iron, lead, copper, etc.

The curable blends may be used to produce flexible, semi-rigid or rigid films, coatings, fibers, molded articles, foamed articles and adhesives.

The following Examples 15 to 22 and 41 to 74 iliustrate the invention. Percentages are by weight unless indicated otherwise.

Examples 1 to 14 Copolymers of ethylene, carbon monoxide, vinyl acetate, and a fourth comonomer as specified in Table I were prepared by mixing the respective monomers at the feed rates shown in Table I, then feeding the resultant mixture into a 700 cc highly stirred reaction vessel together with a catalyst of the type and amount given in Table I.

The reactor pressures and temperatures and the conversion of monomer to polymer are also given in Table I. The reactor residence time was 4.5 minutes. The melt index of the polymer reported in Table I was determined according to ASTM D1238-65T, Condition E.

Example 15 A blend containing 15% of the copolymer of Example 2 with novolak phenolic resin (supplied by "Durez" Divison of Hooker Chemical Company as "Durez" 14000, a powdered 2-step type phenol-formaldehyde resin containing abou 7% hexamethylenetetramine "Durez" is a Registered Trade Mark, was made by dissolving both polymers in tetrahydrofuran. The blend was dried on a steam plate and then pressed into a 2 mil film. The film was cured for 15 minutes at 165"C. in the press at a pressure of 20,000 psi. The cured film from this blend was clear, indicating good compatibility, and could be bent almost 1800 before breaking.

This result is in contrast to the behavior of a film from the straight cured novalak phenolic resin, which is very brittle and breaks under a very small strain.

The compatible nature of this blend is in contrast to that encountered using an ethylenel vinyl acetate/glycidyl methacrylate copolymer, into which no carbon monoxide was copolymerized. An opaque incompatible blend was obtained when this second copolymer was used, indicating the essential nature of the carbon monoxide constituent when clear films are desired. The comonomer ratio of this copolymer was 71/22/7.

Example 16 A solution blend was made containing 35% oí the polymer of Example 2 and the novolak phenolic resin of Example 15. The blend was pressed into a 3" x 3" x i/a ' bar and cured for 10 minutes at 150 C. This bar was cut into bars 21/2" x 1/2" x ills". The Izod impact strength of these bars was 0.39 ft. Ib./inch compared to a value of 0.2: ft. lb.inch for the unmodifed phenolic resin.

Example 17 A 50/50 blend was made from solution using the copolymer of Example 3 and the novolak resin of Example 15. The uncured film, cast from the solution, was clear, indicating compatibility. This film was cured in an air oven at 1 100C. for 20 min. to give a clear, flexible film.

The film could be bent double and creased with out cracking.

This cured film was placed in a beaker con taining boiling acetone. This sample stayed as a film after stirring for 30 minutes, indicating a complete cure.

Example 18 A 50t50blend was made on a 2-roll mill at a temperature of 75"C. 15 Grams of the polymer of Example 3 was blended with 15 grams of a powdered 1-step type phenolic resin (resole) supplied as "Durez" 26164. A 10 mil film was melt pressed from this blend and found to be hazy, indicating only partial compatibility.

This blend was pressed into a bar and cured.

The Izod impact strength of this bar was 2.5.

This is a very high value for a cured polymer.

Example 19 15 g. of the polymer of Example 3 was milled with 15 g. of a powdered two-step phenolic resin (novolak) "Durez" 22091 sold by Hooker Chemical Company, which contained no curing agent. The blend was pressed into a 10 mil film and then held in the press at 150"C. for one (P) hour to cure. The film was clear, showing compatibility and was insoluble in boiling tetrahydrofuran showing a cure.

Example 20 A solution 50/50 blend was made from the polymer of Example 3 and the novolak phenolic resin described in Example 15 containing 8 percent of hexamethylenetetramine. A 10 mil film was pressed at 100 C., the temperature was raised to 1 500C. for 30 minutes. The film was clear.

The tensile properties of this film were: tensile strength, 2150 psi; elongation, 60 percent; tensile modulus, 18,000 psi. When the brokem specimens were returned to the original positions, the elongation above was found to be > 95% elastic (ASTM D-1708-66 [0.2"/ min. crosshead speed] ).

Example 21 A solution blend in tetrahydrofuran was made using 0.5 g. of the polymer of Example 1 and 1.5 g. of liquid diglycidyl ether of bisphenol A with an epoxy equivalent weight of about 190 and a viscosity of about 13,000 cps. at 250C.

(Epon 828 sold by Shell). 0.15 g. of a curing agent triethylenetetramine was added. The solution was evaporated to dryness to form a film. The film was cured by heating over a steam bath for one (1 hour). The film was clear and could be bent double with no indication of brittleness. This behaviour was in contrast to the brittle behavior of a control film made in the same fashion, but without the polymer of Example 1.

Example 22 A solution blend was made in tetrahydrofuran of 50 percent of the polymer of Example 2 and 50 percent of a melamine-formaldehyde resin, hexamethoxymethyl-melamine sold by American Cyanamid ("Cymel" 301 "Cymel" is a Registered Trade Mark) p-toluene sulfonic acid was added to give 0.25 percent by weight, exclusive of the solvent, as a catalyst for cure.

This solution was coated on aluminium, dried and cured at 1500C. for 1 hour. The film was very slightly hazy, flexible, and could be bent double without cracking.

A similar film containing only the melamineformaldehyde resin and catalyst was also coated on aluminum and cured. In contrast, this film was very brittle and cracked when the aluminium was bent.

Examples 23 to 40 hollowing the procedure of Examples 1 to 14 a series of tetrapolymers were prepared. Polymer compositions and reaction conditions are summarized in Table II.

Control Example 1 and Examples 41 to 49 Blends of phenolic resins, based on a 50/50 blend of wood flour and a two-step (novolak) phenolic resin, were made. 8 parts of hexamethylenetetramine were added in the blending step to provide a cure catalyst. All blends contain 40% wood flour for comparative purposes. The polymer of this invention was added to replace a portion of the phenolic, except for Control Example 1 where additional amount of the novolak phenolic resin was used in place of the tetrapolymer of the present invention. Bars 1/s" x 1/2 " X 5t, were molded at 1000C. and cured at 1600C. for 10 minutes.

From the results shown in Table III, it can be seen that one can obtain a higher tensile strength and higher flexural strain at failure with only a minor decrease in modulus (Example 41); or one can obtain a marked increase in flexural strain at failure, a large reduction in modulus with a relatively minor decrease in flexural strength (Example 42 to 49).

Control Example 2 and Examples 50 to 54 Blends of phenolic resin containing wood flour similar to Examples 41 and 42 were molded into 1/a" thick plaques and cured as previously described. The plaques were tested by a falling dart weighing 1/A Ib. (Gardner Tester) to determine the height at which a crack appeared on the reverse side of the plaque. The results in Table IV show that the energy to break can be increased 2-3 fold, or more, depending on the structure of the polymer added.

Control Example 3 and Examples 55 to 59 A commercial grade of a phenolic resin Is compounded specifically with medium length glass fiber and various additives for use in electrical applications. this composition is coded "Durez" 23570. Three tetrapolymers and two terpolymers were added to be 20 percent of the total composition. For comparison, 20 percent of a pure novolak phenolic resin was added to provide a control having the same amount of filler and additivies. Samples were molded, cured and tested for electrical properties. In Table V it is shown that the electrical properties are not seriously impaired. The volume resistivity, however, is improved at least 5-fold.

Examples 60 to 62 Elastomeric, cured products can be made TABLE I COPOLYMER SYNTHESIS Reaction Conditions Product Copolymer Feed Ratio E/Comonomer(c)/ Example Copolymer Monomer Melt Pressure Temp. Catalyst Catalyst(a) CO/Comonomer(d) No. Type Ratio Index (Atmos.) ( C) Type Concentration (Parts by wt.) Conversion (%) 1 E/VA/CO/GMA 60/25/13/2.4 52 1630 180 PB 0.40 11/4.1/0.35/0.19 10.2 2 E/VA/CO/GMA 53/30/11/5.6 660 1630 181 PB 0.30 10/5.0/0.53/0.21 11.8 3 E/VA/CO/GMA 52/27/13/8.4 45 1630 179 PL 0.42 10/4.9/0.43/0.20 10.4 4 E/VA/CO/GMA 56/26/15/3.1 50 1630 161 PL 0.56 10/4.4/0.35/0.11 11.0 5 E/VA/CO/GMA 61/21/15/3.0 94 1630 153 PL 1.30 10/3.1/0.42/0.096 9.9 6 E/VA/CO/GMA 64/21/10/5.4 70 1830 181 RA55 0.59 10/3.2/0.20/0.14 11.5 7 E/VA/CO/GMA 62/22/10/6.0 58 1830 180 RA55 0.59 10/3.3/0.22/0.15 10.8 8 E/VA/CO/GMA 67/17/10/5.9 84 1830 181 RA55 0.82 10/2.6/0.22/0.15 11.1 9 E/VA/CO/GMA 67/17/10.5.8 96 1830 181 RA55 0.88 10/2.6/0.17/0.15 11.6 10 E/VA/CO/GMA 64/21/9/5.9 72 1830 180 RA55 0.66 10/3.3/0.21/0.14 11.0 11 E/VA/CO/GMA 61/25/10/4.5 51 1830 180 PO 0.39 10/4.0/0.30/0.10 10.3 12 E/VA/CO/GMA 63/23/7/7.0 65 1830 174 RA55 0.53 10.2.6/0.20/0.14 11.0 13 E/VA/CO/GMA 64/18/12/6.3 80 1830 180 RA55 1.03 10/2.6/0.25/0.14 11.4 14 E/VA/CO/GMA 63/18/13/5.6 45 1830 180 RA55 0.72 10/2.6/0.34/0.15 11.5 PB=t-Butyl Peroxyisobutyrate PL=t-Butyl Peroxypivalate PO=t-Butyl Peroctoate RA55=2-t-Butyl Azo-2-Cyano-4-Methoxy-4-Methyl Pentane (a) Lbs./M Lbs. polymer GMA=Glycidyl Methacrylate GA=Glycidyl Acrylate TABLE II Reaction Conditions Product Copolymer Feed Ratio E/Comonomer(c)/ Example Copolymer Monomer Melt Pressure Temp. Catalyst Catalyst(a) CO/Comonomer(d) Conversion No.Type Ratio Index (Atmos.) ( C) Type Concentration (Parts by wt.) (%) 23 E/VA/CO/GMA 70/18/9/3.5 60 1830 180 RA-55 .54 10/2.58/.17/.14 11.4 24 E/VA/CO/AGE(1) 68/17/12/2.9 40 1830 180 RA-55 .87 10/2.63/.45/.06 11.3 25 E/MA/(3)CO/GMA 72/11/13/4.2 45 1830 180 RA-55 1.22 10/.25/.30/.11 10.8 26 E/VA/CO/GMA 68/22/8/2.9 400 1700 182 RA-55 1.37 20/5.2/.30/.18 11.5 27 E/VA/CO/GMA 73/17/9/1.2 400 1700 181 RA-55 1.89 20/6.6/.90/.21 11.0 28 E/VA/CO/GMA 62/21/14/3.2 500 1400 180 RA-55 3.94 20/6.6/.90/.19 11.8 29 E/VA/CO/GMA 60/22/14/4.5 50 1830 181 LUP 80 0.21 10/3.3/0.50/.12 12.6 LUP 80=t.Butyl Peroxyisobutyrate RA-55=2-t-Butyl Azo-2-Cyano-4-Methoxy-4-Methyl Pentane RA-70=2-t-Butyl Azo-2-Cyano-4-Methyl Pentane (1) allyl glycidyl ether (2) lbs./M 1bs. of polymer (3) methyl acrylate (4) methyl vinyl ether TABLE II (Cont'd) REACTION CONDITIONS PRODUCT COPOLYMER Feed Ratio Pressure Catalyst E/Comonomer(c)/ Conversion Example Copolymer Monomer Melt (Atmos.) Temp Catalyst Catalyst(a) CO/Comonomer(d) (%) No. Type Ratio Index ( C) Type (2) (Parts by wt.) 30 E/VA/CO/GMA 64/29/4/3.3 350 1450 181 RA-70 .42 14/5.47/0.10/0.09 11.3 31 E/VA/GMA 65/31/4.5 50 1830 181 RA-55 .25 22/6.65/.18 12.2 32 E/VA/GMA 71/24/5.3 15 1830 180 R-55 1.59 10/.42/.10 10.7 33 E/VA/GMA 77/19/4.7 40 1830 181 R-55 .53 10.2.5/.6 11.0 34 E/VA/GMA 71/24/4.2 60 1830 182 R-55 .51 10/3.50/.11 11.8 35 E/VA/GMA 62/34/3.7 70 1830 181 R-55 .41 10/5.65/.11 12.1 36 E/VA/GMA 64/30/6.2 40 1830 181 R-55 .82 10/4.60/.18 12.1 37 E/VA/GMA 68/31/0.9 105 1830 176 RA-55 .08 14/5.40/.027 11.0 38 E/VA/GMA 65/33/2.0 90 1830 177 RA-55 .11 14/5.46/.058 11.3 39 E/VA/GMA 66/30/0.7 230 1830 170 RA-55 .25 14/5.53/.124 11.2 40 E/MVE(4)/GMA 66/26/8.1 1200 1700 160 RA-55 .23 N2/4.1/.08 11.9 LUP 80=t-Butyl Peroxyisobutyrate RA-55=2-t-Butyl Azo-2-Cyano-4-Methoxy-4-Methyl Pentane RA-70=2-t-Butyl Azo-2-Cyano-4-Methyl Pentane (1) allyl glycidyl ether (2) lbs./M lbs. of polymer (3) methyl acrylate (4) methyl vinyl ether TABLE III Flexural Flexural Flexural Example Additive, Modulus Strength Strain at Number Additive Type Amount, % X10-3 psi X10-3 psi Failure, % Control 1 (Phenolic) (20) 1100 13 1.2 41 Tetrapolymer of 20 800 14.5 1.9 Example 28 42 Tetrapolymer of 20 320 10 4.5 Example 26 43 Tetrapolymer of 20 230 6.6 3.9 Example 30 44 Terpolymer of 20 290 6.9 3.3 Example 31 45 Terpolymer of 20 270 6.9 3.8 Example 32 46 Terpolymer of 20 430 6.2 1.5 Example 37 47 Terpolymer of 20 250 5.7 3.2 Example 38 48 Terpolymer of 20 350 5.3 1.8 Example 39 49 Terpolymer of 20 220 5.8 3.8 Example 40 TABLE IV Energy Example Additive to Break Number Additive Type Amount,% Inch - Pounds Control 2 (Phenolic) (25) 1.2 50 Tetrapolymer 25 2.3 of Example 28 25 2.3 51 Tetrapolymer 25 3.2 of Example 26 52 Tetrapolymer 25 5.5 of Example 30 53 Tetrapolymer 25 5.5 of Example 31 54 Tetrapolymer 25 5.5 of Example 32 TABLE V ADDITIVE ARC(1) VOLUME (2) BREAKDOWN (3) EXAMPLE ADDITIVE AMOUNT RESISTANCE RESISTIVITY VOLTAGE NUMBER TYPE % SECONDS X1011 OHM-METERS VOLTS/MIL Control 3 (Phenolic) 20 108 0.23 1072 55 Tetrapolymer of 20 81 14.5 1105 Example 28 56 Tetrapolymer of 20 140 2.2 1051 Example 26 57 Tetrapolymer of 20 119 2.5 1076 Example 30 58 Tetrapolymer of 20 101 8.1 1025 Example 31 59 Tetrapolymer of 20 107 1.2 994 Example 32 (1) Tungsten electrodes (2) ASTM D257 (3) ASTM D149 - Samples about 0.040 inch thick TABLE VI Elonga % Re Stiffness Tensile tion at covery Phenolic Resin Additive 100% Secant Strength, Break, After Example No. Used Additive Type Amount, % Modulus, psi psi % 30 Min.

60 "Durez" 14000 Tetrapolymer 60 2710 3320 110 89 of Example 2 61 "Durez" 14000 Tetrapolymer 70 1540 2800 150 93 of Example 2 62 "Durez" 14000 Tetrapolymer 80 740 1960 190 92 of Example 2 TABLE VII Izod Flexural Flexural Flexural Impact Additive Modulus Strength Strain to % Strength Example No. Additive Type Amount,% X10-2 psi X10-3 psi Failure, % Recovery FT-Ib/Inch Control 4 - None 1,440 16.2 1.1 100 0.39 63 Tetrapolymer 20 400 4.8 1.3 997 0.42 of Example 28 64 Tetrapolymer 20 210 5.0 3.8 90 of Example 26 65 Tetrapolymer 25 150 3.4 4.1 - 0.95 of Example 26 TABLE VIII Flexural Flexural Flexural Izod Example Additive Modulus Strength Strain to Impact/Strength Number Additive Type Amount X1013 psi X10-3 psi Failure Ft-Ib/Inch Control 5 (phenolic) 20% 1400 14.7 1.2 0.20 66 Terpolymer of Ex.33 20% 169 5.0 7.2 1.4 67 Terpolymer of Ex.33 20% 73 2.7 8.0 1.6 68 Terpolymer of Ex.33 20% 60 2.9 9.7 1.3 69 Terpolymer of Ex.33 20% 124 4.9 5.8 1.1 TABLE IX Flexural Addi- Flexural Flexural Strain Izod tive Modulus, Strength To Impact Example Additive Amount psi psi Failure Strength Number Type % X10-3 X10-3 % Ft-Lb/inch Control 6 Phenolic 20 1580 12.8 0.95 0.16 70 Example 28 20 920 14.6 1.9 0.26 71 Example 26 20 160 5.8 5.5 1.4 72 Tetrapolymer of 20 87 3.0 6.0 1.5 Example 30 73 Tetrapolymer of 20 106 3.2 6.0 2.1 Example 31 74 Tetrapolymer of 20 169 4.9 5.5 1.7 Example 32 when the phenolic resin is less than 50% of the blend. Examples of such behaviour are given in Table VI. Note that the 5to elongation to failure is 100-200%, and the elastic recovery of this elongation after failure is about 90%.

Control Example 4 and Examples 63 to 65 A commercial epoxy resin is filled with glass fibers and pelletized for injection molding uses ("Fiberite" E 2748, "Fiberite" is a Registered Trade Mark). Blends were made and evaulated as shown in Table VII.

Control Example 5 and Examples 66 to 69 Blends were made on a 2-roll mill using a glass-filled two-step phenolic resin ("Durez)) 23570). The resin contained sufficient catalyst for cure. Control Example 5 contained 20 percent of an unfilled phenolic resin so that all examples contain the same amcunt of glass filler. The polymers of this invention were added at the 20 percent level. Bars were molded at 100 C. and cured at 160"C. before testing.

From the results in Table VIII it can be seen that a desirable reduction in stiffness, a marked increase in flexural strain to failure, and a remarkable increase in impact strength can be obtained.

Control Example 6 and Examples 70 to 74 Blends were made on a 2-roll mill using a glass-fiber filled phenolic resin FM 1005 produced by the "Fiberite" Corporation. All examples contain 20 percent of the additive, including Control Example 6 so that all sam ples contain the same amount of the glassfiber filler. Bars were molded at 100"C. and cured at 1 600C. before testing.

From the results in Table IX it can be seen that one can obtain a combined increase in flexural strength, strain to failure and impact toughness if desired or a major increase in strain to failure and impact toughness at the expense of flexural modulus and flexural strength depending on the structure of the additive.

WHAT WE CLAIM IS: 1. A curable blend comprising 99 to 1 percent by weight of an organic thermosetting resin selected from phenolic resins, epoxy resins and melamine-formaldehyde resins and 1 to 99 percent by weight of an ethylene copolymer consisting essentially of, by weight, (a) 40 to 90 percent ethylene; (b) 0 to 20 percent carbon monoxide; (c) 5 to 40 percent of a monomer copolymerisable therewith to provide flexible polymers, said monomer being an unsaturated mono- or dicarboxylic acid of 3 to 20 carbon atoms, an ester of such an-unsatu- rated mono- or dicarboxylic acid, a vinyl ester of a saturated carboxylic acid wherein the acid group has 1 to 18 carbon atoms, a vinyl ether wherein the alkyl group has 1 to 18 carbon atoms, acrylonitrile, methacrylonitrile, an alpha-olefin of 3 to 20 carbon atoms, norbornene or a vinyl aromatic compound; and (d) 0.2 to 15 percent of an ethylenically unsaturated monomer of 4 to 21 carbon atoms containing an epoxy group; with the proviso that the organic thermosetting resin is a phenolic resin or a melamine-formaldehyde resin when the ethylene copolymer is a terpolymer consisting essentially of monomers (a), (c) and (d).

2. A blend according to claim 1 wherein monomer (c) of the ethylene copolymer is a vinyl ester of a saturated carboxylic acid wherein the acid group has 1 to 18 carbon atoms, in ester of an unsaturated mono- or dicarboxylic acid of 3 to 20 carbon atoms or a vinyl alkyl ether.

3. A blend according to claim 2 wherein monomer (c) is vinyl acetate, vinyl propionate, vinyl butyrate, methyl acrylate, ethyl acrylate, methyl methacrylate, dibutyl maleate, dimethyl fumarate, vinyl methyl ether or vinyl butyl ether.

4. A blend according to claim 1, 2 or 3 wherein monomer (d) of the ethylene copolymer is an epoxy ester of a copolymerisable unsaturated organic acid, an epoxy ether of a vinyl ether, an epoxy ether of an allyl ether or a mono-epoxy substituted di-olefin of 4 to 12 carbon atoms.

5. A blend according to claim 4 wherein monomer (d) is glycidyl methacrylate, glycidyl acrylate, glycidyl vinyl ether or vinyl cyclohexene monoxide.

6. A blend according to any one of the preceding claims wherein monomers (a) to (d) of the ethylene copolymer are present in amounts by weight (a) 45 to 90 percent, (b) 0 to 15 percent, (c) 10 to 33 percent, and (d) 0.4 to 9 percent.

7. A blend according to claim 6 wherein monomers (a) to (d) are present in amounts by weight (a) 50 to 70 percent, (b) 0 to 3 or 10 to 15 percent, (c) 20 to 30 percent, and (d) 1.5 to 6 percent.

8. A blend according to any one of the preceding claims wherein monomer (c) of the ethylene copolymer is vinyl acetate and monomer (d) is glycidyl methacrylate or glycidyl acrylate.

9. A blend according to any one of the preceding claims wherein the thermosetting resin is a novolak resin.

10. A blend according to any one of claims 1 to 8 wherein the thermosetting resin is a resole resin.

11. A blend according to claim 9 or 10 wherein the thermosetting resin is a phenolformaldehyde resin.

12. A curable blend according to any one of the preceding claims which comprises 5 to 95 percent by weight of the ethylene copolymer and 95 to 5 percent by weight of the thermosetting resin.

13. A curable blend according to claim 12 which comprises 10 to 50 percent by weight of the ethylene copolymer and 90 to 50 percent of the thermosetting resin.

14. A curable blend according to claim 1

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. when the phenolic resin is less than 50% of the blend. Examples of such behaviour are given in Table VI. Note that the 5to elongation to failure is 100-200%, and the elastic recovery of this elongation after failure is about 90%. Control Example 4 and Examples 63 to 65 A commercial epoxy resin is filled with glass fibers and pelletized for injection molding uses ("Fiberite" E 2748, "Fiberite" is a Registered Trade Mark). Blends were made and evaulated as shown in Table VII. Control Example 5 and Examples 66 to 69 Blends were made on a 2-roll mill using a glass-filled two-step phenolic resin ("Durez)) 23570). The resin contained sufficient catalyst for cure. Control Example 5 contained 20 percent of an unfilled phenolic resin so that all examples contain the same amcunt of glass filler. The polymers of this invention were added at the 20 percent level. Bars were molded at 100 C. and cured at 160"C. before testing. From the results in Table VIII it can be seen that a desirable reduction in stiffness, a marked increase in flexural strain to failure, and a remarkable increase in impact strength can be obtained. Control Example 6 and Examples 70 to 74 Blends were made on a 2-roll mill using a glass-fiber filled phenolic resin FM 1005 produced by the "Fiberite" Corporation. All examples contain 20 percent of the additive, including Control Example 6 so that all sam ples contain the same amount of the glassfiber filler. Bars were molded at 100"C. and cured at 1 600C. before testing. From the results in Table IX it can be seen that one can obtain a combined increase in flexural strength, strain to failure and impact toughness if desired or a major increase in strain to failure and impact toughness at the expense of flexural modulus and flexural strength depending on the structure of the additive. WHAT WE CLAIM IS:

1. A curable blend comprising 99 to 1 percent by weight of an organic thermosetting resin selected from phenolic resins, epoxy resins and melamine-formaldehyde resins and 1 to 99 percent by weight of an ethylene copolymer consisting essentially of, by weight, (a) 40 to 90 percent ethylene; (b) 0 to 20 percent carbon monoxide; (c) 5 to 40 percent of a monomer copolymerisable therewith to provide flexible polymers, said monomer being an unsaturated mono- or dicarboxylic acid of 3 to 20 carbon atoms, an ester of such an-unsatu- rated mono- or dicarboxylic acid, a vinyl ester of a saturated carboxylic acid wherein the acid group has 1 to 18 carbon atoms, a vinyl ether wherein the alkyl group has 1 to 18 carbon atoms, acrylonitrile, methacrylonitrile, an alpha-olefin of 3 to 20 carbon atoms, norbornene or a vinyl aromatic compound; and (d) 0.2 to 15 percent of an ethylenically unsaturated monomer of 4 to 21 carbon atoms containing an epoxy group; with the proviso that the organic thermosetting resin is a phenolic resin or a melamine-formaldehyde resin when the ethylene copolymer is a terpolymer consisting essentially of monomers (a), (c) and (d).

14. A curable blend according to claim 1

substantially as described in any one of Examples 15 to 22 and 41 to 74.

15. A shaped articles obtained by moulding a curable blend as claimed in any one of the preceding claims and heating to cure the thermosetting resin.

16. A shaped article according to claim 15 in the form of a film.

17. A shaped article according to claim 15 in the form of a fibre.

18. A shaped article according to claim 15 in the form of a foam.

19. A method of producing a shaped article which comprises dispersing (a) 5 to 95 percent by weight of an ethylene copolymer as defined in any one of claims 1 to 8 in 95 to 5 percent by weight of a thermosetting resin in which said copolymer is soluble, said thermosetting resin being selected from phenolic resins, epoxy resins, and melamine-formaldehyde resins, with the proviso that the resin is a phenolic resin or a melamine-formaldehyde resin when the ethylene copolymer is a terpolymer consisting essentially of monomers (a), (c) and (d); (b) molding the resulting blend; and (c) maintaining the molded blend at an elevated temperature until a crosslinked resin is formed, said ethylene copolymer remaining substantially dispersed in the cured thermosetting resin.