Ethylenically-unsaturated ethers of alkenyl phenols as reactive diluents for bismaleimides

Ethylenically-unsaturated ethers of alkenyl phenols are useful as reactive diluents for bismaleimides. Formulations comprising bismaleimides and the reactive diluents of this invention are particularly useful for producing heat and moisture resistant fiber-reinforced composites.

BACKGROUND OF THE INVENTION 
This invention relates to novel reactive diluents for use with bismaleimide 
formulatioss, and more particularly to ethylenically-unsaturated ethers of 
alkenyl phenols as novel reactive liquid diluents, and to thermosetting 
bismaleimide formulations comprising bismaleimides and the novel reactive 
diluents of this invention. The bismaleimide formulations of this 
invention, when cured, exhibit improved moisture resistance and are 
particularly useful in combination with fiber reinforcement for producing 
heat and moisture resistant composites. The novel reactive diluents of 
this invention provide bismaleimide formulations having improved 
miscibility and compatability with conventional modifiers including 
thermoplastic resins, cyanates and the like, and such formulations have a 
particularly advantageous range of melt viscosities and reactivities. 
High strength, high modulus composites are finding increasing use as 
structural components for use in aircraft, automotive and sporting goods 
applications. Typically they comprise structural fibers such as carbon 
fibers in the form of woven cloth or continuous filaments embedded in a 
thermosetting resin matrix. Such composites may be conveniently fabricated 
from prepreg, a ready-to-mold sheet of reinforcement impregnated with 
uncured or partially cured matrix resin. Resin systems comprising an 
epoxide resin and aromatic amine hardener are often used as the matrix 
resin component of prepreg because they possess an appropriate balance of 
properties for this composite fabrication process. Although the resulting 
composites have high compressive strengths, good fatigue characteristics, 
and low shrinkage during cure, most epoxy formulations absorb moisture and 
are not well-suited for use at 270.degree. F. or greater in a 
moisture-saturated condition. 
Composites designed for use at temperatures of 300.degree. F. or higher may 
employ as the matrix resin a combination of a bismaleimide with one or 
more coreactants such as polyfunctional amines, epoxides, cyanate resins, 
or comonomers containing polymerizable ethylenic unsaturation. 
Compositions based on liquid or low-melting solid coreactants and reactive 
diluents are particularly useful in the production of prepreg materials. A 
variety of such bismalemide-based formulations are now known, and a number 
are available from commercial sources. 
The range of reactive diluents suitable for use with bismaleimide resins is 
rather limited. The use of vinyl ether diluents with bismaleimide resins 
in forming rapid-cure molding resin formulations is disclosed in U.S. Pat. 
No. 4,609,705. Such formulations gel and cure very quickly, and prepreg 
based on such formulations would therefore have a brief processing life or 
"out time". In U.S. Pat. Nos. 4,644,039 and 4,100,140 there are disclosed 
bis-unsaturated coreactants including diallyl-substituted bispenol A, 
diallyl-substituted biphenol, diallyl phthalate, triallyl cyanurates and 
the like, as well as alkenyl phenols such as 2-methoxy-4-allyl phenol 
(eugenol), and 2-allyl phenol. Also disclosed are the corresponding alkyl 
ethers, and particularly the methyl ethers, of these alkenyl phenols. 
Although the corresponding alkenyl ethers are also suggested in general 
terms in the disclosure of U.S. Pat. No. 4,100,140, there is no specific 
disclosure or example of such alkenyl ethers. Bismaleimide compositions 
incorporating a variety of such alkenyl phenols and their use in preparing 
composites are also disclosed. 
Although other liquid diluents are available, including divinyl benzene, 
esters of acrylic and methacrylic acids and the like, many are highly 
volatile, have a noxious odor and may be toxic or strong irritants. Some 
are only poorly miscible with most bismaleimides, and those having 
reactive hydroxyl or amino functionality may induce rapid crosslinking and 
premature gellation of the bismaleimide or interact unfavorably with other 
components of the formulations. 
The range of reactive diluents available for use with bismaleimides is thus 
rather limited, and coreactants and reactive liquid diluents that increase 
the options available to the resin formulator are clearly needed. Such 
diluents, particularly if they offer a range of reactivities and 
viscosities together wth improved miscibility with thermoplastics and 
compatibility with other commonly used additives and modifiers, would 
increase the flexibility needed to provide formulations designed to meet 
the needs of particular end users. In addition, the industry continues to 
require materials with the ability to withstand ever more severe 
environments, including elevated temperatures and exposure to extremes of 
moisture. 
SUMMARY OF THE INVENTION 
This invention relates to reactive diluents for use with bismaleimides and 
to curable formulations comprising bismaleimides and the reactive diluents 
of this invention. 
The reactive diluents are compounds having a plurality of reactive olefinic 
functionalities, and are derived from alkenyl phenols such as eugenol. The 
reactive diluents may be more fully described as ethylenically-unsaturated 
ethers of such alkenyl phenols. These reactive diluents are liquids and 
are miscible with bismaleimides and with other components of 
bismaleimide-based formulations, forming compositions that are 
melt-processable. Formulations comprising bismaleimides and the reactive 
diluents of this invention may be useful as curable coating, casting, 
adhesive and impregnating resins and are particularly useful as matrix 
resins in combination with fiber reinforcement for producing curable 
prepreg, laminates and composites. 
DETAILED DESCRIPTION 
The reactive diluents useful in the practice of this invention are 
ethylenically-unsaturated ethers of alkenyl phenols, which may be more 
fully described and characterized as having the structure 
EQU Alkenylphenyl-O-R, 
wherein R is an ethylenically-unsaturated moiety. 
More specifically, the alkenylphenyl moiety will be derived from an 
alkenyl-substituted phenol, such as, for example, a propenylphenol or an 
allylphenol. Suitable alkenyl phenols may include the various position 
isomers of propenylphenol and allyl phenol as well as ring-substituted 
analogs thereof wherein the additional substituent groups will be those 
that do not react with bismaleimides or otherwise interfere with the 
curing process. Examples of such alkenyl phenols include C.sub.1 to 
C.sub.4 alkoxy-substituted compounds such as eugenol (2-methoxy-4-allyl 
phenol), isoeugenol (2-methoxy-4-propenyl phenol), 4-pro- 
penyl-2,6-dimethoxy phenol and 4-allyl-2,6-dimethoxyphenol, the C.sub.1 to 
C.sub.4 alkyl-substituted alkenylphenols such as the various allyl 
methylphenols, the allyl dimethylphenols, and the like, and 
halogen-substituted compounds such as 2-allyl-4-chlorophenol and the like, 
as well as the propenyl analogs thereof. 
The ethylenically-unsaturated moiety R may be selected from allyl, 
vinylbenzyl, propenylbenzyl, allylbenzyl, and the like, as well as from 
structures having propenylphenoxy and allylphenoxy moieties linked to the 
alkenylphenol through a divalent hydrocarbon group such as an alkylene, 
alkenylene or bisalkarylene group. Examples of reactive diluents suitable 
for use in the practice of this invention include allyl ethers of alkenyl 
phenols such as the allyl ethers of eugenol and isoeugenol, the alkenyl 
benzyl ethers of alkenyl phenols such as the vinylbenzyl ethers of eugenol 
and isoeugenol, the di(alkenylphenyl) ethers of diols, including the 
bis-ethers of lower alkylene glycols and polyalkylene glycols such as 
1,2-bis-(2-methoxy-4-allylphenoxy) ethane, the bis-ethers of 
ethylenically-unsaturated glycols such as 
1,4-bis(2-methoxy-4-allylphenoxy)-2-butene, and the bisethers of 
alkarylene diols such as 
alpha,alpha'-bis(2-methoxy-4-allyl-phenoxy)-meta-xylene and the like, as 
well as analogous compounds wherein the ethylenically unsaturated 
substituents are propenyl groups. 
The reactive diluents of this invention may be prepared by a variety of 
well-known methods, including the etherification of alkenyl phenols with 
an appropriate ethylenically-unsaturated halogen compound, using an 
appropriate alkaline compound as an acid acceptor. For example, such allyl 
ethers may be prepared by combining any of the readily available allyl 
phenols such as 2-allylphenol or eugenol with an allylic halogen compound 
such as allyl chloride in the presence of sodium hydroxide and a suitable 
solvent, while use of phenols with propenyl (.beta.-methylvinyl) 
substituents such as isoeugenol will afford the corresponding propenyl 
analogs. Similarly, the reaction of an alkenylene dihalide or an alkylene 
dihalide such as ethylene dibromide with an alkenyl phenol such as eugenol 
or isoeugenol will provide the corresponding bisalkenylphenyl ethers, 
while the combination of alkenyl phenols with benzylic halides such as 
chloromethylstyrene or an .alpha.,.alpha.'-dihaloxylene will provide the 
corresponding benzyl ethers and bis-ethers. The alkenyl phenols may be 
employed singly or in combination with other alkenyl phenols when carrying 
out such processes to provide a variety of useful product mixtures. 
Allylphenols not readily available commercially may be obtained by 
well-known processes, such as from the corresponding allyl phenyl ethers 
by a thermal isomerization process. These, in turn, may be isomerized to 
form the propenyl analogs. 
The bismaleimides useful in the thermosetting formulations of this 
invention may be any of the bismaleimides derived from aromatic and 
aliphatic diamines, including any of the well-known and widely available 
phenylene diamines and the various diamino-substituted polynuclear 
aromatic compounds such as diaminodiphenyl sulfone, diaminobenzophenone, 
diaminodiphenylether, diaminodiphenylmethane, and like, as well as the 
various aryl compounds having a plurality of aminophenylalkylidene or 
aminophenoxy substituents. Also useful are bismaleimides based on C.sub.4 
-C.sub.20 aliphatic diamines such as the various isomeric alkanes having 
diamino substituents. The bismaleimides may be employed singly or in 
mixtures comprising two or more bismaleimides, which may include both 
aromatic and aliphatic bismaleimides. A great variety of bismaleimides 
suitable for use as matrix resins are well-known in the art, such as are 
recited for example in U.S. Pat. Nos. 4,644,039 and 4,100,140, as well as 
in applicant's recently issued U.S. Pat. No. 4,654,407. Methods for 
preparation of such bismaleimides are well-known, and many such resins and 
resin blends are available from commercial sources. 
The bismaleimide formulations of this invention will comprise 100 parts by 
weight of the bismaleimide resin and from about 10 to about 200 parts by 
weight of the reactive diluent. The formulations will be readily prepared 
by simple mixing operations ordinarily employed in the resin formulating 
art, and may, if desired be compounded at moderately elevated temperatures 
to reduce the viscosity of the mixture. 
The formulations may further include from 0 to about 30 wt. %, based on 
total resin formulation, of a thermoplastic polymer such as, for example, 
a polyaryl ether, a polyaryl sulfone, a polyarylate, a polyamide, a 
polyaryl ketone, a polyimide, a polyimide-ether, a polyolefin, an ABS 
resin, a polydiene or diene copolymer or a mixture thereof. Thermoplastics 
such as polysulfones and phenoxy resins are particularly miscible with the 
bismaleimidereactive diluent formulations of this invention, and may be 
used to adjust resin viscosity and control flow during cure, which is an 
important and unexpected advantage of these formulations. Compositions 
based on combinations of bismaleimides with prior art reactive diluents 
often have little or no miscibility with thermoplastic modifiers. These 
prior art formulations often exhibit poor tack and lack the viscosity 
characteristics needed for producing processable prepreg. 
The formulations of the present invention may further include up to 50 wt. 
%, based on total resin formulation, of other reactive diluents and 
modifiers ordinarily employed in bismaleimide resin compositions, such as, 
for example, vinylic coreactants such as N-vinyl-2-pyrrolidinone, alkylene 
glycol vinyl ethers, vinyl toluene, styrene, divinyl benzene and the like, 
acrylates and methacrylates such as ethylene glycol dimethacrylate, 
acrylates and methacrylates of polyols such as trimethylol propane and 
pentaerythritol, allylic compounds such as triallyl isocyanurate, diallyl 
phthalate, tetraallyl pyromellitate, o,o'-diallyl bisphenol A, eugenol and 
the like. Other coreactive modifiers may also be included in the 
formulations of this invention, such as, for example epoxy resins, cyanate 
ester resins and mixtures thereof, together with appropriate curing aids 
and accelerators typically employed in formulating such curable 
compositions. 
The formulations may also include 0 to 3 wt. % of one or more initiators 
for vinyl polymerization such as di-t-butyl peroxide, dicumyl peroxide, 
1,1-bis(t-butylperoxy) cyclohexane, azo bis-isobutyronitrile, t-butyl 
perbenzoate, and the like. Inhibitors for vinyl polymerizations, such as 
hydroquinone, t-butyl hydroquinone, benzoquinone, p-methoxyphenol, 
phenothiazine, 4-nitro-m-cresol, and the like may also be employed in 
amounts of from 0 to 2 wt. %. 
The bismaleimide formulations of the invention are particularly useful in 
combination with structural fiber for producing fiber reinforced laminates 
and composites and for the manufacture of prepreg. The structural fibers 
which may be used for these purposes include carbon, graphite, glass, 
silicon carbide, poly(benzothiazole), poly(benzimidazole), 
poly(benzoxazole), aluminum, titanium, boron, and aromatic polyamide 
fibers. These fibers are characterized by a tensile strength of greater 
than 100,000 psi, a tensile modulus of greater than two million psi, and a 
decomposition temperature of greater than 200.degree. C. The fibers may be 
used in the form of continuous tows (1000 to 400,000 filaments each), 
woven cloth, whiskers, chopped fiber or random mat. The preferred fibers 
are carbon fibers, aromatic polyamide fibers, such as Kevlar 49 fiber 
(obtained from E.I. DuPont Company) and silicon carbide fibers. The 
composites will generally comprise from about 10 to about 90 wt. % fiber, 
based on total weight of composite. 
Preimpregnated reinforcement, or prepreg, may be made by combining the 
resin formulations with a structural fiber, using any of the variety of 
methods known in the art such as wet winding or hot melt. Tacky, drapable 
prepreg tape or tow can be produced having a long prepreg out time at room 
temperature, typically one to four weeks. 
The compositions of this invention may be used as matrix resins for 
composites, high temperature coatings, and adhesives. When reinforced with 
structural fibers, they may be used as aircraft parts as automotive parts 
such as drive shafts, bumpers, and springs, and as pressure vessels, tanks 
and pipes. They are also suitable for use in a wide variety of sporting 
goods applications such as golf shafts, tennis rackets and fishing rods. 
In addition to structural fibers, the composition may also contain 
particulate fillers such as talc, mica, calcium carbonate, aluminum 
trihydrate, glass microballoons, phenolic thermospheres, and carbon black. 
Up to half of the weight of structural fiber in the composition may be 
replaced by filler. Thixotropic agents such as fumed silica may also be 
used.

EXAMPLES 
The following examples serve to give specific illustrations of the practice 
of this invention but they are not intended in any way to limit the scope 
of this invention. 
EXAMPLE 1 
Allyl Ether of Eugenol (2-methoxy-4-allyl-1-allyloxybenzene) 
A 5 l 4-neck flask equipped with an overhead stirrer, addition funnel, 
reflux condenser, nitrogen inlet and outlet, and heating mantle was 
charged with 2 l of n-propanol, 656.8 g of Eugenol, and 165.0 g of freshly 
opened sodium hydroxide pellets. The mixture was stirred and heated at 
reflux until the sodium hydroxide had dissolved. 
Allyl chloride, 400 ml, was then slowly added over 20 minutes while gentle 
reflux was continued. The lemon yellow reaction mixture was then refluxed 
an additional 5 hours and stirred at room temperature overnight. 
The precipitated sodium chloride was removed by filtration and the 
n-propanol was stripped under vacuum on a rotary evaporator. The crude 
product was diluted with 2 l of methylene chloride and that solution 
washed twice with water and twice with brine. The methylene chloride was 
removed under vacuum on a rotary evaporator and the product then filtered 
through sodium sulphate and held under vacuum overnight. The yield of 
liquid diluent was 811 g and the NMR was consistent with the expected 
structure. The boiling point of this diluent was over 250.degree. C. at 
atmospheric pressure. The diluent was stable up to that temperature 
without polymerizing and, even when cured in the presence of a free 
radical inhibitor (see schedule A as discussed hereinbelow), showed only 
partial cure and could not be tested mechanically. 
EXAMPLE 2 
Vinylbenzyl Ether of Eugenol (VAD) 
A 5 l 4-neck flask equipped with an overhead stirrer, thermometer and 
temperature controller, condenser, DeanStark trap, addition funnel, 
nitrogen atmosphere, and heating mantle was charged with 1 l of toluene, 1 
l of DMSO, and 270 g of Eugenol. After flushing the stirred mixture with 
nitrogen for 15 min, a charge of 130.2 g of 50.32% aqueous sodium 
hydroxide was added and the funnel rinsed with additional water to insure 
transfer. 
The reaction was heated to reflux and continued until all the water had 
been azeotropically removed plus 100 ml of additional toluene. After 
cooling the reaction mixture to 100.degree. C., a 250.0 g portion of vinyl 
benzyl chloride was added followed by a toluene rinse. Heating at 
100.degree. C. was continued for 30 min. and the reaction mixture was then 
cooled to room temperature. 
The reaction mixture was transferred to a 12 l stirred separatory funnel 
and diluted with 2 l of dichloromethane. This solution was washed with 
3.times.2.5 l water, 1.times.2.5 l 5% aq. NaOH, and a final 2.5 l water. 
The washed organic solution was passed through silica gel and then 
inhibited with 0.46 g methoxyphenol, 0.46 g benzoquinone, and 0.46 g 
Eugenol. Several passes through a Pope molecular still were made to remove 
dichloromethane; the final residue weight was 401 g (83%). The proton and 
carbon NMR were consistent with the expected structure. 
EXAMPLE 3 
Di-Eugenol Ethers of Ethylene Glycol 
A 2 l 3-neck flask equipped as in Example 1 (except no addition funnel) was 
charged with 164.3 g of Eugenol, 75.1 g of 1,2-dibromoethane, 124.4 g of 
potassium carbonate, and 1 l of acetone. The reaction was stirred and 
heated to reflux for about 18 hrs. to give a bright yellow slurry. The 
cooled reaction mixture was transferred to a separatory funnel, diluted 
with 1 l of dichloromethane, and washed with 4.times.1 l water, 1.times.1 
l 0.5% NaOH, and 1 l water. The washed organic solution was passed through 
silica gel and the dichloromethane was removed under vacuum to give 37 g 
of a yellow oil. NMR analysis showed 66% of the expected diether and 34% 
unreacted Eugenol. 
EXAMPLE 4 
BMI Formulation with VAD (Example 2) 
A mixture of 32 ml VAD and 68 g of SED-M BMI was blended and heated at 
90.degree. C. under vacuum in a rotary evaporator. After 15 min. a 
homogeneous mixture was discharged from the flask into two molds comprised 
of glass plates and a Teflon spacing frame. The larger mold measured about 
10".times.8".times.1/8" and the small measured about 
6".times.4".times.1/16". Both frames were about half filled. 
The casting were cured according to the following schedule: 
25.degree..fwdarw.100.degree. C. at 1.degree. C./min., hold 1 hr. 
100.degree..fwdarw.180.degree. C. at 1.degree. C./min., hold 3 hrs. 
180.degree..fwdarw.240.degree. C. at 1.degree. C./min., hold 3 hrs. 
240.degree..fwdarw.275.degree. C. at 1.degree. C./min., hold 3 hrs. 
275.degree..fwdarw.25.degree. C. at 3.degree. C./min. 
The cured materials were then cut into samples for DMA and tensile strength 
testing. The composition had a Tg of 265.degree. C., a tensile modulus of 
542 ksi, tensile strength of 6.3 ksi, and an elongation of 1.25%. The 
materials absorbed 1.7-2.4% H.sub.2 O after 2 weeks immersion at 
160.degree. F. 
EXAMPLE 5 
BMI Formulation with VAD (Example 2) 
A mixture of 6.8 g of SED-M BMI and 3.2 g VAD was blended on a rotary 
evaporator at about 125.degree. C. until homogeneous. It was mixed and 
held under vacuum an additional 10 minutes for degasing and then poured 
into a small 1/16" thick casting frame such as that described in Example 
4. The clear mixture was cured by heating in an oven according to the 
following schedule: 
25.degree..fwdarw.100.degree. C. at 1.degree./min., hold 1 hr. 
100.degree..fwdarw.180.degree. C. at 1.degree./min., hold 3 hrs. 
180.degree..fwdarw.240.degree. C. at 1.degree./min., hold 5 hrs. 
240.degree..fwdarw.25.degree. C. at 3.degree./min. 
The cured casting had a Tg of 243.degree. C. and absorbed 1.4% water after 
soaking 2 weeks at 160.degree. F. 
EXAMPLES 6-8 
The procedure of Example 5 was substantially repeated using the ingredients 
listed in Table I. Heating temperatures ranged between 90.degree. C. and 
140.degree. C. The cured castings gave Tg values and water absorption 
levels as listed in Table I. 
TABLE I 
______________________________________ 
Example Diluent Tg H.sub.2 O 
No. BMI (gr.) (gr.) (.degree.C.) 
Abs., % 
______________________________________ 
5 SEDM 6.8 VAD 3.2 243 1.4 
6 MDA 5.0 VAD 5.0 310 1.9 
7 C353 5.45 VAD 5.0 300 2.1 
8 C353 6.8 VAD 3.2 &gt;300 2.3 
______________________________________ 
Abbreviations: 
SEDM = 4,4"-bis(3maleimidophenoxy)diphenyl sulfone. 
MDA = The bismaleimide of 4,4"-methylene dianiline. 
C353 = Compimide 353, a mixture of aliphatic and aromatic bismaleimides 
from BootsTechnochemie GMBH. 
VAD = Vinylbenzyl ether of Eugenol (Example 2). 
Control examples were prepared using commonly employed coreactants in place 
of the reactive diluents of this invention, and tested as for Examples 
5-8. The properties are summarized in Table II. The controls were cured 
substantially by the schedule of Example 5. 
TABLE II 
______________________________________ 
Ex. BMI Diluent Tg H.sub.2 O 
No. (g.) (g.) (.degree.C.) 
Abs., % 
______________________________________ 
A 7.5 SEDM 1.0 NVP 270 3.5 
1.4 EGDM 
B 5.4 MDA 4.6 DABA 284 3.7 
C 8.2 353 0.4 TAIC &gt;300 3.5 
1.5 DVB 
0.1 PSF 
0.1 PKHH 
D 7.0 353 3.0 DAP &lt;200 5.1 
______________________________________ 
Notes: 
NVP = N--vinyl pyrrolidone; EGDM = ethylene glycol dimethacrylate; DABA = 
o,o'-diallyallylbisphenol A; TAIC = triallyl isocyanurate; DVB = divinyl 
benzene (55%); DAP = diallyl phthalate; see also notes to Table I. 
It will be apparent from a consideration of the Examples that the 
compositions comprising bismaleimides and the reactive diluents of this 
invention, Examples 4-8, exhibit substantially improved resistance to 
moisture and, in many instances, substantially higher Tg values when 
compared with formulations based on commonly employed reactive diluents, 
summarized as control Examples A-D in Table II. 
EXAMPLES 9-16 
The procedure of Example 5 was substantially repeated using the ingredients 
listed in Table III. Heating was carried out at temperatures between 
90.degree. and 140.degree. C. 
The following cure schedules were employed as indicated in Table III: 
______________________________________ 
Cure Schedules (.degree.C.) 
______________________________________ 
A. 25 .fwdarw. 79 at 
1.5.degree./min., 
hold 2 hrs. 
79 .fwdarw. 177 at 
1.5.degree./min., 
hold 4 hrs. 
177 .fwdarw. 246 at 
1.degree./min., 
hold 4 hrs. 
246 .fwdarw. 25 at 
1.5.degree./min. 
B. 25 .fwdarw. 79 at 
1.5.degree./min., 
hold 6 hrs. 
177 .fwdarw. 246 at 
1.degree./min., 
hold 4 hrs. 
246 .fwdarw. 25 at 
1.5.degree./min. 
C. 25 .fwdarw. 79 at 
1.5.degree./min., 
hold 2 hrs. 
79 .fwdarw. 177 at 
1.5.degree./min., 
hold 4 hrs. 
177 .fwdarw. 235 at 
1.degree./min., 
hold 4 hrs. 
235 .fwdarw. 25 at 
1.5.degree./min. 
D. 25 .fwdarw. 79 at 
1.5.degree./min., 
hold 2 hrs. 
79 .fwdarw. 177 at 
1.5.degree./min., 
hold 4 hrs. 
177 .fwdarw. 220 at 
1.degree./min., 
hold 4 hrs. 
220 .fwdarw. 25 at 
1.5.degree./min. 
______________________________________ 
TABLE III 
______________________________________ 
Ex. BMI Diluent Tg H.sub.2 O 
No. (g.) (g.) Cure (.degree.C.) 
Abs., % 
______________________________________ 
9 SEDM 7.4 ECO 2.6 A 280 2.6 
10 BAPP 7.4 ECO 2.6 A 310 2.6 
11 BAM 7.0 ECO 3.0 B 265 2.1 
12 TPE 6.9 ECO 3.1 B 320 3.8 
13 C353 6.2 ECO 3.8 A 360 4.7 
14 C353 6.2 ECO 3.8 C 355 4.0 
15 C353 6.2 ECO 3.8 D 360 4.1 
16 C353 6.8 ECO 3.2 C 370 4.4 
______________________________________ 
Note: 
For test conditions, see text; abbreviations: 
ECO = Allyl ether of Eugenol (Example 1); 
SEDM = 4,4'-bis(3maleimidophenoxy)diphenyl sulfone; 
BAPP = 4,4'-bis(4maleimidophenoxy)diphenyl isopropylidene; 
BAM = alpha, alpha'-bis(4maleimidophenoxy)-metadiisopropylbenzene; 
TPE = 1,3bis(4-maleimidophenoxy)benzene; 
C353 = Compimide 353, a mixture of aliphatic and aromatic bismaleimides 
from BootsTechnochemie GMBH. 
The Examples of Table III, when compared with the Control Examples of Table 
II, demonstrate the generally higher Tg values that result from 
formulations employing the reactive diluents of this invention. 
EXAMPLES 17-27 
The procedures of Example 5 were substantially followed in preparing and 
testing the compositions summarized in Table IV as Examples 17-27. The 
heating and stirring of the mixtures was accomplished at temperatures 
between 90.degree. and 140.degree. C. The cure schedules also were varied 
slightly as in the Examples of Table III. 
TABLE IV 
______________________________________ 
H.sub.2 O 
Ex. BMI Diluent BT Resin Tg Abs., 
No. (g.) (g.) (g.) Cure (.degree.C.) 
% 
______________________________________ 
17 BAPP 7.0 ECO 2.5 
U 0.5 B 300 2.9 
18 BAPP 6.7 ECO 2.3 
U 1.0 B 292 3.0 
19 BAPP 6.7 ECO 2.3 
M 1.0 B 276 3.0 
20 BAPP 6.7 ECO 2.2 
M 1.5 A,B 270 2.7 
21 BAPP 5.7 ECO 2.3 
M 2.0 A 265 2.0 
22 TPE 6.2 ECO 2.8 
U 1.0 B 284 2.7 
23 C353 4.0 ECO 2.4 
U 3.6 A 258 2.9 
24 C353 6.0 ECO 2.5 
M 1.5 A .about.280 
4.3 
25 C353 6.5 ECO 2.0 
M 1.5 A .about.300 
4.5 
26 C353 6.25 ECO 2.0 
M 1.75 A .about.300 
3.9 
27 C353 6.0 ECO 2.0 
M 2.0 A .about.270 
4.7 
______________________________________ 
Notes: 
BT Resin: U = Unmodified BT2160 BMICyanate resin based on MDABMI (10%) an 
bisphenol A dicyanate (90%); M = BT2164, a polyester elastomermodified 
version of BT2160 (both BT resins were obtained from Mitsubishi Gas 
Chemical Company); for additional abbreviations, see text preceding Table 
I. 
The compositions of Examples 17-27 demonstrate the utility of formulations 
including cyanate resins. Equivalent formulations based on o,o'-diallyl 
bisphenol A as the reactive diluent were also prepared; all were gelled 
and unusable. 
EXAMPLES 28-37 
The procedure of Example 5 was substantially repeated using the ingedients 
in Table V. The heating temperatures were between 90.degree. and 
140.degree. C. In these examples the basic bismaleimide mixture was 
modified by the addition of rubbery thermoplastics. 
TABLE V 
______________________________________ 
H.sub.2 O 
Ex. BMI Diluent Modifier Tg Abs., 
No. (g.) (g.) (g.) Cure (.degree.C.) 
% 
______________________________________ 
28 6.7 BAPP 2.3 ECO 
1.0 VTBN A .about.260 
1.2 
29 6.7 BAPP 2.3 ECO 
1.0 CTBN A .about.230 
1.6 
30 6.9 BAPP 2.5 ECO 
0.6 PETP A .about.300 
2.6 
31 6.9 BAPP 2.3 ECO 
0.8 VTBN A .about.320 
2.3 
32 6.2 TPE 2.8 ECO 
1.0 CTBN B .about.260 
2.7 
33 7.5 C453 2.5 ECO 
(25% CTBN) 
A .about.360 
2.0 
34 8.0 C453 2.0 ECO 
(26% CTBN) 
A .about.360 
2.7 
35 6.0 C453 2.0 ECO 
(20% CTBN) 
A .about.360 
3.3 
2.0 C353 
36 6.0 C453 2.5 ECO 
(20% CTBN) 
A .about.360 
2.9 
1.5 C353 
37 3.0 C453 3.4 ECO 
(10% CTBN) 
A .about.350 
2.4 
3.6 C353 
______________________________________ 
Notes: 
VTBN = Vinylterminated butadiene/acrylonitrile liquid rubber, VTBN 1300X2 
(B. F. Goodrich Co.); CTBN = Carboxylterminated butadiene/acrylonitrile 
liquid rubber, either CTBN 1300X8 or CTBN 1300X13 (B. F. Goodrich Co.); 
PETP = a 50/50 blend of two thermoplastic elastomeric polyesters, LP011 
and LP035, M.W. of each approx. 16,000 (Nippon Gosei, Japan); (wt % CTBN) 
= amount included with C453; C453 = 2 parts Compimide 353 and 1 part CTBN 
carboxyterminated nitrile rubber (BootsTechnochemie GMBH); see also notes 
to previous tables. 
Examples 28-37 illustrate the particular advantages of ECO in providing 
processible resins with high levels (i.e., &gt;10%) of rubber modifiers. The 
low viscosity of ECO is very useful in formulations of this type, and the 
high Tg values and low water uptake are notable for compositions having 
rubber contents of as great as 25 and 26% by weight. 
EXAMPLES 38-42 
The procedure of Example 5 was substantially repeated using the ingredients 
listed in Table VI. The heating temperatures were between 90.degree. and 
140.degree. C. In these examples the bismaleimide/diluent mixture was 
modified by the addition of a rubbery thermoplastic polymer plus a BT 
resin. 
TABLE VI 
______________________________________ 
H.sub.2 O 
Ex. BMI Diluent Tg Abs., 
No. (g.) (g.) Modifier Cure (.degree.C.) 
% 
______________________________________ 
38 6.2 BAPP 2.2 ECO 1.0 BT2160 A 245 2.3 
0.6 PETP 
39 5.5 BAPP 2.5 ECO 1.0 BT2160 A 200 1.3 
1.0 VTBN 
40 5.9 BAPP 2.1 ECO 1.0 BT2160 B 240 2.0 
1.0 VTBN 
41 5.9 BAPP 2.1 ECO 1.0 BT2160 B 215 3.2 
1.0 CTBN 
42 6.25 C353 
1.6 ECO 1.75 BT2164 A .about.290 
4.0 
0.4 PETP 
______________________________________ 
Notes: For abbreviations, see notes to prior tables; for cure schedules, 
see text. 
EXAMPLES 43-49 
The procedure of Example 5 was substantially repeated using the ingredients 
in Table VII. Heating temperatures were between 90.degree. and 140.degree. 
C. Cure schedules and abbreviations are described above or in the table 
footnotes 
TABLE VII 
______________________________________ 
H.sub.2 O 
Ex. Reactive Diluents 
Cure Tg Abs., 
No. BMI (gr.) (gr.) (gr.) Sched. 
(.degree.C.) 
% 
______________________________________ 
43 7.0 BAM 1.5 ECO 
1.5 DABA 
E 295 1.4 
44 7.0 BAM 1.5 ECO 
1.5 DABS 
E 285 1.7 
45 7.0 C353 1.5 ECO 
1.5 TM 120 
A .about.340 
2.4 
46 6.0 C353 2.5 ECO 
1.5 DABA 
E .about.340 
3.3 
47 6.0 C353 2.5 ECO 
1.5 DABS 
A .about.340 
2.4 
48 6.0 C353 2.0 ECO 
2.0 DABA 
F .about.340 
1.6 
49 6.0 C353 2.4 ECO 
1.0 DABS 
F .about.350 
3.8 
______________________________________ 
Cure Schedules (.degree.C.) 
______________________________________ 
E. 25 .fwdarw. 130 at 
1.5.degree./min. 
Hold 2 hrs. 
130 .fwdarw. 177 at 
1.5.degree./min. 
Hold 4 hrs. 
177 .fwdarw. 246 at 
1.degree./min. 
Hold 4 hrs. 
246 .fwdarw. 25 at 
1.degree./min. 
F. 25 .fwdarw. 177 at 
1.5.degree./min. 
Hold 6 hrs. 
177 .fwdarw. 246 at 
1.degree./min. 
Hold 4 hrs. 
246 .fwdarw. 25 at 
1.degree./min. 
______________________________________ 
TM = a bis(allylphenyl) compound available as a BMI toughening modifier 
from BootsTechnochemie, GMBH. 
DABS = o,o'-diallyl bisphenol S (Nippon Kagaku). 
The above examples demonstrate the use of mixtures of the reactive diluents 
of this invention with commercially available diluents and BMI modifiers. 
The use of ECO, in particular, is advantageous in raising the Tg values of 
these formulations over those obtained with DABA or TM 120 alone. DABS is 
a powdered material, not a liquid, and could not be used as a single 
diluent in BMI formulations. In combination with ECO it provides high Tg 
values and low water uptake along with melt processability. Control 
examples summarized in Table vIII demonstrate the lower Tg values obtained 
in the absence of ECO. 
TABLE VIII 
______________________________________ 
Control Cure Tg H.sub.2 O 
No. BMI gr. Diluent gr. 
Sched. 
(.degree.C.) 
Abs., % 
______________________________________ 
E 6.0 C353 4.0 DABA F 300 -- 
F 6.5 C353 3.5 DABA F 290 3.6 
G 7.0 BAM 3.0 DABA A 270 1.4 
______________________________________ 
Tensile properties were obtained according to ASTM D-638 on larger castings 
(1/8" thick) made from some of the above formulations. These are listed in 
Table IX. 
TABLE IX 
______________________________________ 
Ex. Tg Tensile Tensile 
No. (.degree.C.) 
Strength Modulus 
Elong. 
______________________________________ 
33 .about.360 
6.4 ksi 326 ksi 
2.8% 
10 310 7.2 ksi 463 ksi 
1.9% 
21 265 7.2 ksi 495 ksi 
1.7% 
______________________________________ 
These properties show an attractive balance of toughness and high Tg 
values. 
EXAMPLE 50 
Dissolution of Polysulfone in ECO 
A 2 l round bottom flask equipped with a thermometer, an overhead stirrer 
and nitrogen atmosphere was charged with 800 g of ECO. The stirred ECO was 
heated with an oil bath to 100.degree. C. and 200 g of Udel P-1800 
(powdered polysulfone available from Amoco Performance Products, Inc.) was 
added over 25 min. Stirring and heating were continued for 30 min. and the 
clear solution was then discharged. The P-1800/ECO solution was pourable 
at room temperature. 
This Example demonstrates the ease of dissolution of a thermoplastic 
modifier in the diluent, ECO, alone. In contrast, the commercial diluent 
DABA (Ciba-Geigy) is only very slowly pourable at room temperature even in 
the absence of thermoplastic modifiers. 
EXAMPLE 51 
Preparation of Bismaleimide Formulation Using Pre-Blend of Polysulfone and 
ECO 
A 3 1 round bottom flask equipped with a thermometer, an overhead stirrer 
and a vacuum outlet was charged with 800 g of a pre-blend of 20 weight 
percent Udel P-1800 in ECO such as that prepared in Example 50. This 160 g 
P-1800/640 g ECO mixture was stirred and heated to 140.degree. C. with an 
oil bath. A 1200 g charge of solid Compimide 353 (shattered into small 
pieces) was added over 15 min. Heating and stirring were continued under 
vacuum for 20 min. and the resin formulation was then discharged and let 
cool. 
EXAMPLE 52 
Fabrication of Prepreg Tow 
The resin of Example 51 was applied via a hot-melt process to single tows 
of carbon fiber (either T-300 or T-40 from Amoco Performance Products, 
Inc.) and wound onto take-up creels as prepreg tow. After freezing and 
thawing, the tow showed excellent de-spooling characteristics and was 
readily re-wound into test specimens. 
EXAMPLE 53 
Preparation of Bismaleimide Formulation 
A 3 l round bottom flask equipped with a thermometer, an overhead stirrer 
and vacuum outlet was charged with 640 g of ECO and the ECO was heated 
with an oil bath to 140.degree. C. 1200 g of solid Compimide 353 
(shattered into small pieces) was added over 15 min. During this addition 
and dissolution the temperature of the mixture dropped to about 
100.degree. C. The temperature of the mixture was raised to 140.degree. C. 
again and 160 g of Udel P-1800 powdered polysulfone was added over 10-15 
min. Vacuum was applied to the stirring, heated mixture for 30 min. and it 
was then discharged. 
The formulation of this Example is identical to that of Example 51 except 
that the Udel P-1800 was dissolved in the ECO/Compimide 353 mixture 
instead of ECO alone. 
Control Example H 
A 250 ml round bottom flask equipped with a thermometer and overhead 
stirrer was charged with 33 g of DABA and the stirred DABA was heated to 
120.degree. C. with an oil bath. A 62 g charge of solid Compimide 353 
(shattered into small pieces) was added over several minutes and 
dissolved. During this 25 min. period the temperature of the mixture 
dropped to 115.degree. C. A 5 g charge of Udel P-1800 was then added. 
After stirring at 120.degree. C. for about 1 hour, the P-1800 was still 
not dissolved. The temperature was raised to 130.degree. C. After one 
hour, the P-1800 had still not dissolved but the resin had gelled and 
could not be removed from the flask. 
This Control Example demonstrates the difficulties in preparing a 62/33/5 
Compimide 353/DABA/P-1800 blend. By comparison Example 53, where a 60/32/8 
Compimide 353/ECO/P-1800 blend was readily prepared, demonstrates one of 
the advantages of the diluents of this invention. It will thus be apparent 
from a consideration of Examples 17-27 and 28-37 and the corresponding 
control examples, as well as from Example 53 and Control Example H that 
the composition of this invention exhibits good miscibility and 
compatability with modifiers such as cyanates, rubbers, thermoplastics and 
the like. 
EXAMPLE 54 
Preparation of Bismaleimide Formulation 
A 500 ml round bottom flask equipped with a thermometer, an overhead 
stirrer and a temperature controller was charged with 48 g of ECO. The ECO 
was stirred and heated to 70.degree. C. with an oil bath. 120 g of 
Compimide 353 (shattered into small pieces) was added over 6 min. and the 
mixture was then heated to 110.degree. C. The Comp. 353 had dissolved by 
the time the temperature reached 85.degree. C. A 6 g charge of powdered 
phenoxy resin (PKHH, from Union Carbide Corp.) and a 6 g charge of Udel 
P-1800 were then added and the temperature raised to 120.degree. C. After 
90 minutes all the added materials were dissolved, and the mixture was 
charged with 20 g of diallyl bisphenol S (DABS) powder (Nippon Kagaku 
Co.). After mixing one hour at 120.degree. C., the mixture was cooled to 
110.degree. C., stirred an additional hour, and then discharged. 
A small casting prepared from this resin and cured according to schedule F 
gave a Tg of about 350.degree. C. 
The resin had excellent film properties and was readily fabricated into 
prepreg tape with carbon fibers and used to prepare composite samples. 
EXAMPLE 55 
Preparation of Bismaleimide Formulation 
The procedure of Example 54 was substantially repeated except that the 
mixing time after addition of all the resin ingredients was reduced to 15 
min. at 120.degree. C. and the resin was then discharged. This resin had a 
lower viscosity and was well suited for the fabrication of prepreg tow as 
described in Example 52. 
EXAMPLE 56 
The procedure of Example 54 was substantially repeated using the following 
ingredients, in parts by weight: 
Compimide 353--60 parts 
ECO--21 parts 
DABS--10 parts 
Udel 3900--9 parts 
Udel 3900 is a lower molecular weight polysulfone resin available from 
Amoco Performance Products, Inc. 
EXAMPLE 57 
Preparation of Carbon Fiber Composite 
A mixture of 1120 g of Compimide 353 bismaleimide, 680 g ECO, 200 g VTBN 
1300X22, and 40 g Cab-o-Sil (N-70-TS, hydrophobic) was stirred at 
125.degree. C. until a film sample withdrawn showed good film properties 
and little or no reticulation. A total heating period of about 7 hours was 
used. 
The resin mixture was coated on a differential silicone-coated release 
paper and then fabricated via standard prepregging procedures into a 
carbon fiber prepreg product using T-40 fibers (12K), available from Amoco 
Performance Products, Inc. An edge delamination test composite, 
(.+-.25.sub.2 /90).sub.s, was fabricated from this prepreg and gave an 
average edge delamination strength of 21 ksi. The Tg of the resin cured 
under similar conditions was .about.350.degree. C. 
EXAMPLES 58-60 
The procedure of Example 57 was substantially repeated using the resin 
compositions and fibers listed in Table X. 
The composites were tested for edge delamination strength and gave the 
values shown. These results demonstrate the toughening effects of the 
polysulfone modifier in Example 60, the rubber modifier in Example 57, and 
the mixed phenoxy/polysulfone modifier in Example 59, compared with 
Example 58, containing no modifier. 
TABLE X 
______________________________________ 
Example Resin 
No. Compositions Fiber EDS (ksi) 
______________________________________ 
57 Ex. 57 T-40 21 
58 Ex. 47 T-40 16 
59 Ex. 54 T-650* 21 
60 Ex. 56 T-40 22 
______________________________________ 
*T-650 fiber has properties similar to T40 fiber. 
The invention will thus be seen to be directed to the use of 
ethylenically-unsaturated ethers of alkenyl phenols as reactive diluents 
for bismaleimides and to compositions comprising bismaleimides and 
ethylenically-unsaturated ethers of alkenyl phenols. The curable 
bismaleimide formulations of this invention may comprise from 10 to 200 
parts by weight of an ethylenically-unsaturated ether of an alkenyl phenol 
per 100 pbw of the bismaleimide. The formulations may further comprise 
from 10 to 90 wt. % structural fiber, preferably carbon fiber, from 0 to 
50 wt. % of one or more additional co-reactants selected from epoxy 
resins, cyanate resins, and ethylenically-unsaturated monomers, and from 0 
to 50 wt. % of one or more resin modifiers selected from thermoplastics, 
rubbery polymers and mixtures thereof. While the invention has been 
illustrated by various representative examples and embodiments, it will be 
apparent that further additions and modifications are possible without 
departing from the spirit and scope of the invention as set forth in the 
appended claims.