Note: Descriptions are shown in the official language in which they were submitted.
-- 2 --
~7(~97
This invention is directed to reinorced
composites made from ~ thermosetting composition
containing hemiformals of phenol and a miscible
polymer. These composite have~excellent physical
properties and show excellent flame resistance.
Until recently, liquid hemiformal
compositions of phenol have been generally unknown
although there has been speculation in the
literature about hemiformals of phenol for some time.
Illustrative of such literature is WalXer,
FORMALDEHYDE, 3rd Edition, published by Reinhold,
Publishing Corporation, New York, (1964), pages 305,
306 wherein the following is stated:
"In the absence of added catalysts,
anhydrous formaldehyde and paraformaldehyde dissolve
in molten phenol without apparent reaction to give
clear, colorless solutions which smell strongly of
formaldehyde. In such solutions, it is probable
that some solvation takes place and hemiformals,
C6 50CH20H, C6H50CH20CH20H, etc., are
present. However, studies of formaldehyde polymers
have demonstrated that phenol is a solvent for these
compounds and the majority of the dissolved
formaldehyde in phenolic sol~tions may be in the
polymerized state. Studies by Fitgerald and
Martin involving the measurement of hydroxyl ion
concentrations in dilute, alkaline, aqueous
ormaldehyde in the presence and absence of the
sodium phenolate of mesitol indicate that hemiformal
44. Fi~zgerald, J.S., Martin, R.J.L., Australian J.
Chem. 8, 194-214 (1955)
D 12824-1
- 3 -
~2~7097
concentrations are too 6mall to be measured in this
way. However, in our opinion hemiformal formation
with a hindered phenol, such as mesitol, would be
similar to hemiformal formation with tertiary butyl
S alcohol which does not show any appreciable
solvation of formaldehyde. There is a definite
analogy of nonaqueous phenol formaldehyde ~olutions
to 601utions of formaldehyde in alcohols and other
polar solvents. According to Reychler , a small
percentage of sodium phenolate catalyzes the
solution of linear formaldehyde polymers in phenol,
just as sodium alcoh~lates catalyze solution in
methanol, ethanol, and other alcohols. That
hemiformals are produced is also indicated by the
isolation of methyl phenyl formal from an
acid-catalyzed reaction of phenol with formaldehyde
solution containing methanol
CH20(aq) CH30H
~ OH > ~ OC~20H >
~ OCH20 H3 H20
One of the difficulties with the conclusion
which is raised in the Walker article is that the
hemiformal is produced from an acid-catalyzed
reaction of phenol with formaldehyde solution
containing methanol. It is notoriously well known
that acids act to catalyze the reaction of phenol
102. Reychler, A., Bull. Sot. Chim. t40) 1,
1189-95 (1907), Chem Abs. 2 p 1266 (1908)
20. Breslauer, J., Pictet, A. Berichte, 40 3785
(1907)
D-12824 1
1~70gt~
with formaldehyde to effect normal alkylation of
phenol by formaldehyde to produce the phenolic
resins. ~hus what is 6een by Walker a~ a 6uggestion
of the existence of the hemiformal may be nothing
more than the known reaction between methanol and
formaldehyde in the presence of an acid catalyst to
form a product which is subsequently reacted with
phenol to yield the ether product which is
characterized as the final product of the reaction.
Actually a reaction between formaldehyde and phenol
to produce the hemiformal wouId have yielded an
equilibrium reaction and this is totally absent from
the reaction characterized by Walker; suggesting
again that in the theoretical reaction disclosed by
Walker the formaldehyde is first stabilized with
methanol and then the prod~ct is reacted with phenol.
Bakeland and Bender in an article in
"Industrial and Engineering Chemistry" Volume 17,
No. 3, pages 225 -237 (1925) make the following
statements concerning the formation o~ a theoretical
hemiformal of phenol:
"The phenol first unites directly with the
aldehyde to form a mixed ether-alcohol compound
(XXXIII), and the resulting ether gro~p very rapidly
rearranges to the phenol.
R R\ /OH Rearranges R jOH
~)~ = O t- HOC6H5 C > C
R' R' OC6H5 rapidly R C6H4H
(XXXIII) (XXXIV)
D-12824-1
~2~0~7
C6H50H ~ R CC6H5 Sometimes rearrange; R /C6H40~
R C6~40H ~lowly R C6H40H "
(XXXV) ~XXXVI)
Thus, Bakeland and Bender clearly indicate
that if the hemiformal exists it i~ at best a
transitory material which is unstable under the
conditions at which it was produced and is a
theoretical composition constitutinq an intermediary
in the generation cf phenolic resins.
Strupinskaya et al. in Plast. ~ssy 1968
~12), at pp 18-20 described the preparation of a
product by the absorbtion of formaldehyde into
molten phenol at a ~ormaldehyde to phenol ratio of
3:10. This corresponds to a ~ormaldehyde to phenol
mole ratio of 0.94:1. The source of formaldehyde
was a converter gas ~tream containing about 10~
methanol and analysis of the product showed it to
contain up to 8~ methanol. The presence of methanol
suggests that this reference refers to a ~ethanol
~tabilized product similar to that disclosed in
Walker, cited above, wherein formaldehyde reacts
with methanol and subsequently reacts with phenol to
form the ether product. The low formalde~yde to
phenol ratio also indicates that hemiformals havins
average formaldehyde to phenol ratios higher than
1:1 would likely not have been formed by their
method.
In Belgium Patent 667,360 issued on
November 16, 1965 to Chemische Werke Huels A. G. is
disclosed the treatment of various
- hydroxy-compounds, inclùding phenol, with monomeric
D-12B24-1
9~
formaldehyde at a formaldehyde to phenol ratio of
1:1. The low formaldehyde to phenol ratio would
indicate that any hemlformal formed would probably
have no more than an average of one formaldehyde
moiety in the hemiformal chain structure. As
disclosed in Bakeland and Bender, cited above,
hemiformals are known in the art as transitory or
unstable species and would be expected by one of
ordinary skill to be increasingly unstable as the
length of the hemiformal chaln increases. It would,
therefore, be expected that additional formaldehyde
added in the Huels process would react with the
pllenol at another site on the aromatic ring, such as
at the para or ortho-position, rather than Eorming
hemiformals with higher formaldehyde to phenol
ratios. A person normally skilled in the art would
normally expect that hemiformal compositions having
formaldehyde to phenol ratios greater than 1:1,
wherein hemiformal chains having more than one
formaldehyde moiety are formed, would be unstable,
forming other phenol-formaldehyde resinous products
or dlsassociating to form free formaldehyde.
D-12824-1
~2~ 7
~ h~ flr-t tl~ re ~ h~ n ~t~bll~lhod
~t b~f~ a o~ ~nol ~ ~ ylDl-tod
~h~nol ~l~V~ boen ~a~2 ~ich hJY~ r~co~,n~2~d ~t~bll~y
~r~ â~ol~bl~, an~ c~n ~e utlll~ ln the ~omlst~on o~
5 a ~ar~t~ ~f a~6duc~ a~t~cul~rlg
~h~nol-~nrm~1~2hyd~ r~n~ n r:~n~ n P~t~nt
~ppl~c~t~n, ~orlJl llo. 4~17t'~4~ y Cov~e2, ~rc~e an~
t:ho~ flld D~c~mber 15~ 1982 and U.S. I'atent No.
4,~ 3,129, ~h~roln llqul~ heml~orm~l c~po~l~lon~ of
10 ph~nol pr~fl~ y ~he roQctlon of i~orDI~ldehyde and
phQn~l ~r~ clo~o~. .
The ho~if~ there~n ~l~clo~d ~re
h~DIiformals o~ ~henol, nd hemlfo~ o~
methylol-t~d ~henol haYlng the fo~ul~s;
(I) ~(CH2) N
(II) ~pH
r ~ tcH 0(CH 0 ) H~
2 2 lb c
ltCH OH)
2 d
(ITI~ Q~CW 0
~ 2 n
-b~ ~CH 0~CH 0) Jl)
~CH ON)
2 d
~her~ln ~ o~lt~ nwl~ber o~ llt 1~15t 1,
~r~'Dly ~ ~alue o~ 1 to ~ut 5, olo~t ~r2fcr~bly
~ ~lu~ of ~bout a.2 to 2.5; ~ ~ 1 to ~bout 5,
D-ï2824-~
~Z~71)97
- 8
l to about ~, d is 0 to about 2, and the sum of c and
d is at least 1 and no greater than 3.
Al~o disclosed are mixtures of the above
hemiformals and also mixtures of any of the above
with hemiformals of substituted phenols or oil
modified phenols. As disclosed in the above cited
applications, these hemiformals are of low viscosity
and are stable at temperatures between about 35C and
55C.
These hemiformal compositions are very
reactive in the the presence oE an acid or base
catalyst typically use in aldehyde-phenol
polymerization reactions and are useEul in forming
phenolic-type resinous products.
In United States Patent No. 4,433,119 is
described the use of the above-described hemiformal
compositions to form solutions of thermoset
compositions with other polymeric materials, such as
phenol-formaldehyde resole and novolac resins,
~romatic polyester, polycarbonate, unsaturated
polyester, poly(aryl ether), urea-formaldehyde, and
melamine-formaldehyde polymers to form thermosetting
compos~tions. These solutions are stable, and are of
low viscosity. It has now been found that these
thermosetting compositions are par~icularly useful in
D-12824-1
~2~3~0~7
- 8A -
the formation of reinforced composites. They are
p~rticularly useEul in molding techniques such as
liquid injection molding (LIM), reaction injectlon
molding (RIM), hydraJecting, and resin transfer
molding (RTM) wherein liquid thermosetting
compositions are injected directly into a mold where
they are cured; resulting formation of a fabricated
part.
These thermosetting compositions are also
adaptable to the sheet molding compound method ~SCM),
wherein a resin, reinforcing fiber and other
additives are mixed under low shear conditions and
the resulting viscous mixture cured to non-tacky
sheets. Final cure to finished parts is then carried
out in a mold.
It has been found that these solutions can
be used to form composites having a relatively high
content of reinforcing material and having excellent
physlcal properties and flame resistance. In most
thermosetting compositions, particularly of the
phenolic type, there has been a limitation of the
amount of reinforcing fiber that can be added to
D-12824-1
~2~'~'0~
form composites. This is due in large part to the
high viscosity of the~e compositions, many of which
are nearly solid, which necessi~ates high s~ear
mixing with the reinforcing material and injection
under high shear conditions into the mold. This
results in significant attrition of the reinforcing
material, thus lowering the strength of the final
composite. The high viscosity also prevents
6ufficient wetting of the fiber and mixing with the
fiber. This results in composites of poor physical
properties and ~epara~ion of the composites at the
site of the fibers. For this reason fiber content
of such composites has generally been limited to
about 40 weight percent or below. Solvents have
been used to lower the viscosity, but these upon
cure of the resin volatilize which causes formation
of voids in the composite and leads to excessive
mold pressures.
Since it is desirable to have high
reinforcing fiber content in the composites, to
obtain the superior physical properties obtainable
thereby, a phenolic resin having a low viscosity
that can be used to ~orm 6uch high fiber content
composites without encountering the problems
discussed above, would be very desirable.
The liquid thermosetting compositions
disclosed above, containing hemiformals of phenol,
are of low viscosity, thus a high shear mixing step
is unnecessary to incorporate the reinforcing
material into the co~position. The reinforcing
material may optionally be placed directly in the
mold before injection of the thermosetting
composition. The composition is of low enough
viscosity such that the reinforcing material is
D-12824-1
- 10 -~26~'~097
quickly wetted and intimately incorporated in the
thermosetting composition. Upon cure, the resulting
composite, therefore, has superior physical
properties.
Generally, molding techniques such as liquid
in~ection molding and sheet molding compounds have
been restricted to polyesters due to the
difficulties, described above, that occur when using
most other thermosetting resins. Because of the
excellent physical properties and flame resistance of
phenolics, a phenolic-type resin useful in the above
molding processes to form composites would be
desira~le. The present invention includes the
composites made from the low-viscosity solutions as
described in the above citad United States Patent No.
4,433,11~.
The composites of the invention comprise
from about 20 to 70 weight percent preferably 45 to
70 weight percent based on the weight of the
composite, of a reinforcing material and from 30 to
80 percent, preferably 30 to 55 weight percent based
on the weight of the composite, of the reaction
product of a liquid thermosetting solution which
comprises; 40 to 80 weight p0rcent, preferably 50 to
70 weight percent, based on the liquid solution, of
D-12824-1
'70~'7
- lOA -
one or more of the hemiform~ls as described herein
and from 20 to 60 weight percent, preferably 30 to 50
wei~ht percent, based on the liquid solution, of one
or more of the polymers as described below.
The liquid thermosetting solutions useful
for use in the composites of the invention comprise a
hemiformal and a polymer.
The hemiformal compositions useful in the
composites of the invention can be represented by
the following formulas:
D-128~4-1
1~7097
(IV) O~CH2O)~H
~3 ~x
(V) OH
RX ~}(C~120(OE120bH)C
~CH20H)d
(VI) ~ C~2)nH
Rx~ ~ CH20 ( CH2bH ) c
(~H2OH~d
wherein n is a positive number of at least 1,
preferably about 1 to about 5, most preferably about
1.2 to about 2.5. b iB 1 to about 5, c iB 1 to
about 3, and d is O to about 2, x is O to 3, the sum
of c and d is at least 1 ~nd no greater than 3 and
the sum of c, d, and x is at lea~t 1 but no greater
than 5, where x=O for ~t least 50 mole percent of
the hemiformal, and with respect to the R
substituent, ~t least 2 of the or~ho- and para-
positions are free in relation to the -OH and
-O~CH2)nH groups. It is underseood that these
numbers for n, b, c, d and x represent average
values and an actual hemiformal composition will
comprise a equilibrium mixture of various
hemiformals of phenol as represented by the above
formulas. R is ~ny substituent typically employed
in conjunction with ~ phenolic ~tructure. With
respect to R~ it is preferably a monovalent radical
which includes alkyl of fxom about 1 to about 18
carbon atoms, cycloal~yl from 5 to 8 carbon ato~s,
D-12824 1
- 12 -
~2~7097
aryl containing ~rom 1 to about 3 aro~atic rings,
aralkyl, alkaryl, slkoxy containing fro~ 1 to about
18 carbon atoms, aroxy cont~ining 1 to 3 aromatic
nuclei, h~lide such as choride, bromide, fluoride,
and iodide: alkyl ~ulphides having from 1 to ~bout
18 carbon atoms, aryl sulphides having from 1 to
about 3 aromatic nuclei, and the like with the proviso
that at least 50 mole percent of a hem~formal mixture
be unsubstituted with respect to R, i.e. x ~ 0 for
50 mole percent of the ~emiformal composit$on.
The hemiformals shown above are formed by
the reaction o formaldehyde with the hydroxyl-group
of a pnenol t~ ror~ ~le~iror~16 of ~n~2..01~ and/or the
reaction with the methylol group of a methylolated
phenol to form hemiformals of methylolated phenol.
Thi.s i5 accompl~shed by reactin~ formaldheyde with
liquid phenol and/or with a solution containing
methylolated phenol.
The liquid phenols suitable for use in
forming hemiformals of phenol useful in the
invention are of the formula:
OH
~x
where R and x are def ined above and where at least
50 mole percent o~ the phenol is unsubstituted wiSh
respect to R. The substitution with respect to the
R substituent should be such that at least two
reactive sites on the aromatic ring of the para- and
D-12824-1
., ~ . .
- 13 ~ 1 ~ ~ 0 9'7
ortho positions in relation ~o the phenolic hydroxy
remain free. ~he liquid phenol may be in ~olution
wi~h a 601vent, that i8 unreactive to phenols and
aldehydes, or be essentially pure molten phenol.
S Preferably, the phenol i8 molten phenol. Another
source o~ suitable liquid phenols are those prepared
by reacting phenol and an oil such as linseed oil or
tung oil in the presence of an acid ion exchange
resin. It is well known that these so-called
oil-modified phenols comprise complex mixtures
containing phenol and vari OU6 subs t i tut ed phenols
derived from reaction of the phenol with the sites
of unsaturation in the carbon-chains of the oils.
The resulting substituted or modified phenol mixture
can then be treated with formaldehyde as is
described herein to produce a hemiformal mixture.
In using oil modified phenols to maXe hemiformals,
at least 50 mole percent of the phenol should be
unreacted with the oils.
The suitable methylolated phenols are of
the formula: OH
VIII ~ ~ (CH2H)a
where a is 1 to about 3, and R and x are defined
above, and the sum of x and a does not exceed 5.
Although the methylolated phenols can be isolated
and reacted as such with formaldehyde to form
hemiformals, they are preferably formed in situ by
reacting a liquid phenol, as defined above, and
formaldehyde in the presence of a divalent metal
catalyst defined below. Thus, hemiformals of
methylolated phenol can be formed directly from
liquid phenols without isolating the methylolated
D 12824-1
- . . .. .... .. .. . . . .
~ 14 -
~2~7~
phenol~ ~enerally, when phenol and formaldehyde are
reacted without ~ divalent metal ~atalyst
essentially no methyl~lated phenol is formed, the
~ncatalyzed reaction forming methylol phonols being
S very slow. Therefore, essentially all of the
hemiformals ~ormed in a ca~alyst-free reaction
mixture are formed by reaction of the phenolic
hydroxy ~roup and are represented by formula (IV).
If a divalent metal catalyst is present in a
reaction mixture o2 phenol and formaldehyde,
methylolated phenols are formed. Therefore, both the
phenol hydroxy and phenol methylol groups
participate in hemiformal production and equilibrium
mixtures of hemiformals of Formulas IV, V and VI are
formed. Thus the reaction may be carried out
catalyst-free to ~orm hemiformals essentially of
Formula IV, or be carried out with a divalent metal
catalyst to form hemiformals of Formulas IV, V and
VI.
The catalyst-free reaction to form
hemiformals of Formula IV is preferably carried out
by passing gaseous formaldehyde through molten
phenol. The molten phenol may be phenol ~r se or
phenol which is oil-modified or substituted with R
as characterized above. The gaseous formaldehyde
may be obtained from a number of sources. A
preferred method of producing gaseous formaldehyde
is by heating and decomposing paraformaldehyde into
formaldehyde and passing the formaldehyde, free of
water, into molten phenol. Another method for
producing gaseous formaldehyde is to take the
formaldehyde directly as produced by the oxidative
decomposition of methanol and introducing the
formaldehyde, free of water, to the molten phenol.
D-12824-1
- 15 -
The reaction between the ~onomeric or ga~eous
formaldehyde and the molten phenol take6 place at a
temperature ~t which the phenol i6 molten, such as
from melting point of un~ubstituted phenol, about
40C to about 75-C, preferably about 45C to about
60-C.
When using substituted phenols the ~elting
temperature may differ, therefore the reaction
temperature may need to be higher to achieve a
molten phenol. In any case the temperature ~hould
not exceed 75C,
As stated above it is desirable that the
gaseous formaldehyde should be free of water.
However, providing formaldehyde which is free of
water is quite difficult to do and in the normal
case water will be introduced with the formaldehyde
which is provided to the reaction. Usually the
amount of water which is tolerable in the practice
of this invention is that a~ount of water which will
provide in association with the hemiformal a water
concentration of up to about 15 weight percent,
basis the total weight of the hemiformal
composition. In the preferred embodiment it is
desirable that the a~ount of water which is present
in the resultant he~iformal not exceed about 5
weight percent, basis the total weight of the
composition.
As described above, the reaction to form
essentially only he~ifosmals of Formula IV does not
have to be carried out in the presence of ~ny
catalyst and preferably the reaction is carried out
in the absence 9 any catalyst. The typical acidic
or basic catalysts which are utilized in the
reaction of phenol with formaldehyde to produce
D-12824-1
- 16 -
97
resinous structures adversely affect the formation
of the hemiformal and their absence from the
reaction is highly preferred.
The reaction between the gaseoue
formaldehyde and the molten phenol is carried out
with stirring so as to effect intimate admixture of
the reactants and to a~sure uniform reaction. The
reaction may be carried out at subatmospheric or
superatmospheric pressures, however, in the usual
case one will practice the hemiformal reaction at
atmospheric pressure conditions. Since the uncatalyzed
reaction between forma~dehyde and phenol to make the phenol
hemiformal is only mildly exothermic, very little in
' the way of temperature control is necessary in order
to produce the desired hemiformal products.
The reaction carried out in the presence of
a divalent-metal catalsyt to form an equilibrium
mixture of hemiformal6 of formulas IV, V and VI is
preferably carried out by reacting essen~ially
water-free paraformaldehyde with molten phenol at a
temperature of about 60-C to 100C preferably about
80~C to about 90C.
The reaction takes place in the presence of
a divalent metal cation such as magnesiu~, calcium,
lead, manganese, strontium, barium, zinc, cadmium or
mercury, at a pH of about 3 to 8, preferably from
about 4 to 6. Typically, the metal cation is
supplied as a salt or as an alkoxide such as a
carboxylate salt, or a methoxide or ethoxide of the
metal in combination with a mild acid to achieve the
desired pH. Suita~le sal~s include the formates,
acetates, benzoates, and valerates. Examples of
these salts include zinc acetate dihydrate, calcium
formate, manganous acetate, lead acetate and zinc
D-12824-l
- 17 ~ ~ ~709
benzoate.
The divalent ~etal catalyst is typically
present at a concentration of about 0.2 to 1 weight
percent, preferably about 0.4 to about 0.7 weight
percent, based on the total weight.
The paraformaldehyde can be introduced
directly to the liquid phenol. Preferably the
paraformaldehyde is water-free.
As ~tated above it is desirable that t~e
0 paraformaldehyde be es~entially free of wa~er.
However, providing a ~ource of paraformaldehyde
which is free of water is quite difficult to do and
in the normal case water will be carried along with
the paraformal-dehyde which is provided to the
reaction. Usually the amount of water which is
tolerable in the practice of this invention is that
amount of water which will provide in association
with the hemiformal, a water concentration o~ up to
about 15 weight percent, ba~ed on the total weight
of the hemiformal composition. In the preferred
embodiment it is desir~ble that the amount of water
which is present in the resultan~ hemiformal not
exceed about 5 percent, based on the total weight of
the hemiformal composition.
The reaction between parafor~aldehyde and
the molten phenol is carried out with stirring so as
to effect intimate admixture of the reactants and
the metal catalyst and to assure uniform reaction.
~he reaction may be carried out at subatmospheric or
superatmospheric pressures, however, in the usual
case one will practice the hemiformal reaction at
atmospheric pressure conditions. Since the catalyzed
reactions between formaldehyde and phenol to ~ake
phenol hemiformals, methylolated phenols and
~-12824-1
- 18 -
7~
hemifor~als of methylolated phenol, are exothermic,
a cooling ~ater bath may be required to maintain
the reaction temperature.
The polymer~ suitable for use in the liquid
thermosetting solutions used in the invention are
of the phenol-for~aldehyde resole,
phenol-formaldehyde novolac, aromatic polyester,
polycarbonate, unsatureated polyester, poly(aryl-
ether), urea-~ormaldehyde and ~elamine-formaldehyde
type. They must be mi~ci~le with the hemifor~al and
be capable of forming a ~olution with the hemiformal
that has a viscosity low enough to be useful in
injection molding or sheet ~olding compound
methods. The viscosity of the hemifor~al-polymer
solution is preferably less than about 500,000 cps
for use in sheet molding compound methods and most
preferably le~s than about 10,000 Cp5 for use in
molding methods such as LIM, RIM or RTM. The
viscosity depends on the concentration and molecular
weight of the polymer or polymers u~ed.
The phenol-formaldehyde resole polymer6
that can be used in the composites of the invention
include phenolic resins produced by reacting ~n
aldehyde and phenol at an aldehyde to phenol molar
ratio equal to or greater than one, generally
~reater than one, and generally in the presence of
an alkaline cat~lyst. Resoles are generally
characterized as eo~positions that can be cured to a
ther~oset state by the application of heat without
additional aldehyde. The aldehyde component is
usually formaldehyde, although not restricted to
it. Other aldehydes ~uch ~s acetaldehyde,
furfuraldehyde and the like can replace part or all
D-12824-1
-- 19 --
~L2~ 97
of the formaldehyde employed in the preparation.
Those skilled in the ~rt are fully familiar with
resoles, their ~tructure, and methods of manufacture.
The phenol-formaldehyde novolac polymers
that can be used in the composites of the invention
are phenolic resins that require additional aldehyde
or its equivalent, such as hexamethylene~etramine,
to cure to a thermoset s~ate. They are produced by
reacting an aldehyde and a phenol at an aldehyde to
phenol ratio of less than one, usually in
conjunction with an acidic catalyst. Those skilled
in the art are fully fa~iliar with novolacs, their
structure, and methods of manufacture.
The aromatic polyesters useful in tne
composites of the invention can be obtained by the
condensation of a difunctional phenol or mixture of
difunctional alcohol and phenol with a dicarboxylic
acid. The polymerization is performed in 6uch a way
that the resulting polyester contains the phenolic
moiety as the terminal group. An~ong the
difunctional phenols useful for the preparation of
these polyesters one can name hydsoquinone,
2,2-bis-(4-hydroxyphenyl~propane (bis-phenol A),
bis(hydroxyphenyl)ether, bis(hydroxyphenyl)-thio-
ether, ~is(hydroxyphenyl)-methane, bis(hydroxy-
phenyl)sulfone, and the like. Suitable difunctional
alcohols include ethylene giyco_, butanediol,
hexanediol, cyclohexane dimethanol. Among the
suitable dicarboxylic acids are maleic acid, fumaric
acid, terephthalic acid, isophthalic acid,
naphthalene dicarboxylic acids as well as alXyl
substituted homologs of these acids, whesein the
alkyl groups contain fsom 1 to 4 carbon atoms.
Otner suitable dicarboxylic acids are ylutaric acid,
D-12824-1
.
~2¢7097
- 20 -
adipic ~cid, suberic ~cid, azelaic acid, seb~clc
acid, and dodecane dioc acid.
The arom~tic polyesters useful in the
compositions of the invention may cont~in any
substituent which will not adversely Qffect the
miscibility or solubllity of these polymers in the
hemiformal or the subsequent cure of the mixture to
a thermosee~ Among such substituents one csn name
halide, hydrocarbyl, alkoxy, ether and thioether.
Illustr~tive of suitable aromatic
polyesters for use in the compositions of this
invention one can n~me bisphenol-A terminated,
poly(bisphenol-A iso- or terephthalate), bisphenol-A
terminated polyethylene terephthslate, snd the
like. A preferred arom~tic polyester is the
poly(bisphenol-A iso- or terephthalate) of the
general formulQ
1~0~ O-CO--3--CO ~ 0_~
Preferably, the aromatic polyesters should have a
molecular weight less than ~bout lO,000.
The unsatur~ted polyesters useful in the
compositlons of this invention are well known; these
polyesters are ch~racterized by having at least one
internal or terminal unsaturat~on, i.e., -C=C-, which
is capable of reacting with a phenol or methylol
phenol compound by an alkylation reaction of the
double bond and an ortho- or para- position to the
hydroxyl of the benzene ring. Gener~lly, due to
availability or ease of preparation the uns~turated
polyester is structopendant, i.e., the re~ctive
unsaturation 1s present at ~n internal rather than
at a terminal position ~nd usually the internsl
D-12824-l
i~
- 21 -
~ 7()9~
unsaturation i~ alpha to a carbonyl group.
The ~uitable struct~pendant unsaturated
polyesters are rea~tion products of maleic
anhydride, maleic acid and/or fumaric acid with a
difunctional alcohol such as propylene glycol,
diethylene glycol, lt3-butanediol and the like or a
dihydroxy phenol such as ~ phenol A, and the like,
or hydroquinone and the like. Isophthalic ~cid
and/or terephthalic acid m~y also be included in the
mixture. A preferred unsaturated polyester is a
poly~er formed by reaction mixture of isophthalic
and/or terephthalic acid, maleic acid and/or fu~aric
acid and a difuncional alcohol of the formula
HO-R'-OH where R' is a substituted or unsubstituted
alkylene or arylene, ~aid polymer having the
repeating unit;
n
- C-CH=CH-CO-O-R'-O-CO ~ CO-O-R'~O-
The unsaturated polyesters useful in the
compositions of this invention may contain any
substituent which will not adversely affect the
miscibility of these polymers in the he~i~ormal or
the subsequent cure of the mix~ure to a thermoset.
Am~ng such substituents one can name halide,
hydrocarbyl, alkoxy ether ~nd thioether. Preferably
the molecular weight i~ less than lO,OOO.
The aromaeic polycarbonates useful in the
invention are polyesters of carbonic acid and a
dihydric phenol.
The polycarbonates are pepared by reacting
the dihydric phenol with a carbonate precur~or.
D-12824-l
~LZ~7~97
- 22 -
Typical of some of the dihydric phenols th~t may be
employed Are bisphenol-l, bis(4-hydroxyphenyl)-
methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane,
4,4-bis(4-hydroxyphenyl)-heptane, (3,3'-dichloro-
4,4'-dihydroxydiphenyl)meth~ne, and the like. The
terminal group of the dihydric phenol should be
phenol which has at least one para- or ortho-
position to the phenolic hydroxy ~ree for reaction
with the hemiformsl. Other dihydric phenols of the
bisphenol type Are described in, for example, U.S.
Patents 2,999,835, 3,02B,365 ~nd 3,334,154.
It is, of course, possible to employ two or
more different dihydric phenols, or a copolymer of a
dihydric phenol with a glycol or with hydroxy or
acid termin~ted polyesters or with u dlbasic ecid in
the event a carbonate copolymer or inter-polymer
rather than ~ homopolymer ls derived for use in the
preparstion of the aromatic carbonate polymer.
The carbon~te precursor may be either a
carbonyl h~lide, a carbonate ester, or a
haloform~te. The carbonyl halides which c~n be
employed herein are carbonyl bromides, carbonyl
chlorlde ~nd mixtures thereof. Typ1cal of the
c~rbonate esters which may be employed herein are
diphenyl carbonate, di(halophenyl)carbonates such as
dl-(chlorophenyl)carbonate or di-~bromophenyl)car-
bonate, etc., di-(~lkylphenyl)csrbon~tes such as
di(tolyl)cflrbonate, di(naphthyl)carbonate,
di(chloronaphthyl)carbonate, etc., or mixtures
thereof. The haloformates suitable for use herein
include bls-haloformate of dihydric phenols for
example, b~schloroformates of bisphenol-A, of
hydroqu~none, etc., or glycols, for example,
bishaloformates of ethylene glycol, neopentyl
D-12824-1
- 23 -
1;2~7097
glycol, polyethylene glycol, etc. ~le other
carbonate precursor~ will ~e apparent to those
skilled in the ar~, carbonyl chloride, al50 ~nown as
phosgene, is preferred.
The aromatic polycarbonate polymers may be
prepared by methods well Xnown in the art by using
phosgene or a halofor~ate and by employing a
molecular weight regulator, an acid acceptor and a
catalys~. The ~olecular weight regulators which can
be employed in carrying out the process include
monohydric phenols, such as phenol, para-tertiary-
butylphenol, para-bromophenol, primary and secondary
amines, etc. Preferably, a phenol is employed as
the molecuar weight regulator.
A suitable acid acceptor may be either an
organic or an inorganic acid acceptor. A suitable
organic acid acceptor is a tertiary amine and
includes materials, ~uch as pyridine, tsiethylamine,
dimethylaniline, tributylamine, etc. The inorganic
acid acceptor may be one which can be either a
hydroxide, a carbonate, a bicarbonate, or a
phosphate of an alkali or alkaline earth metal.
The catalysts for making an aromatic
polycarbonate can be any of the suitable catalyst~
that aid the polymerization of, for example,
bisphenol-~ with phosgene. Suitable catalysts
include tertiary amines, such as triethylamine,
tripropylamine, N,N-dimethyl-aniline, quaternary
ammonium compounds, 6uch as tetraethylammonium
bromide, cetyl triethyl ammonium bromide,
tetra-n-heptylammonium iodide, and quaternary
phosphonium compounds, such as n-butyltriphenyl-
phosphonium bromide and methyl triphenyl phosphonium
bromid2.
D-12824-1
~ 24 -
~Z~7097
The aromatic polycarbonates can be prepared
in a one-phase (homogeneous solution) or two-phase
~interfacial) sy6tems when phosgene or ~ halofor~ate
are used. Bulk reactions are possible when the
diarylcarbonate precursors are used.
The aromatic polycarbonates useful in the
compositions of this invention may contain any
substituent which will not adversely affect the
miscibility of these polymers in the hemiformal or
the subsequent cure of the mixture to a thermoset.
Among such substituents one can name halide
hydrocarbyl, alkoxy, ether, and thioether. The
aromatic polycarbonates 6uitable for use in the
invention preferably have a molecular weight less
than about lO,OOO.
The poly(aryl-ether) resin components
suitable for use in the invention are linear,
thermoplastic polyarylene polyether polysulfones,
characterized by arylene units interspersed with
ether and ~ulfone linkages, and by at least one
terminal or pendant phenol moiety which is capable
of reacting with an aldehyde or methylol phenol
compound. These resins may be obtained by reaction
of an alkali me~al double salt of a dihydric phenol
and a dihalobenzenoid compound, either or both of
which contain a sulfone or ketone lir.kage i.e.,
-SO2- or -CO- between arylene groupings, to
provide sulfone or ketone units in the polymer chain
in addition to arylene units and ether uni.s. The
polysulfone polymer has a basic structure comprising
recurring units of the ~ormula.
O E O E'
wherein E is the residuum of the dihydric phenol and
E' is the residuum of the benzenoid compound having
D-12824-l
, ~, .. ..
' - .~ ' :'
- 2~ -
~l2~7~)97
an inert electron withdrawing group in nt least one
of the positions ortho and para to the valence
bonds; both of said residua are valently bonded to
the ether oxygens through aromatic carbon atoms.
Such polysulfones are included within the class of
polyarylene polyether resins described in U.S.
patent 3,264,536 and 4,1~8,837, for example~ A
terminal phenol can be obtained by using a
stoichiometric excess of the dihydric phenol
component so that the terminating group is derived
from the dihydric phenol component.
The residuu~ of a dihydric phenol, E is
derived fro~ dinuclear phenols haYing the structure:
~A)r (Al )
r
OH(Ar Rl Ar)OH
Wherein Ar is an aromatic group and preferably i5 a
phenylene group, A and Al may be the same or
different inert substituent groups, such as alkyl
groups having from 1 to 4 carbon atoms, halogen
atoms, i.e., fluorine, chlorine, bromine or iodine,
or alkoxy radicals having from 1 to 4 carbon ato~s,
r and rl are integers having a value of from O to
4, inclusive, and Rl is representative of a bond
between aromatic carbon atoms as in dihydroxydi-
phenyl, or is a divalent radical, including, forexample, Co, O, S, S-S, SO2 or a divalent organic
hydrGcarbon radical, ~uch as alkylene, alkylidene,
cycloalkylene, or the halogen, alkyl, aryl or like
substituted alkylene, alkylidene and cycloalkylene
radicals as well as alkarylene and aromatic radicals
and a ring fused to both Ar groups.
Typical preferred poly(aryl-ether) poly~ers
D-12824-1
,
. ;
- 26 - ~ 2~7 0 g 7
have recurring units having the following ~tructure:
tA)r (~l)r
R2 e;3
as described in U.S. Patent 4,108,837, supra. In
the foregoing formula A and Al can be the same or
different inert substi~uent groups that will not
adversely affect the fiolubility or miscibility of
the polyme~ in the hemiformal or the subsequent cure
to a thermoset. These include alkyl groups having
from 1 to 4 carbon atoms, halogen atoms (e.g.,.
fluorine, chlorine, bromine or iodine) or alkoxy
radicals having from 1 to 4 carbon atoms, r and r
are integers having a value of fro~ 0 to 4,
inclusive. Typically, Rl is representative of a
bond between aromatic carbon atoms or a divalent
connecting radical and R2 represents sulfone,
carbonyl, or sulfoxide. Preferably, Rl represent~
a bond between aromatic carbon atoms. Even more
preferred are the thermoplastic polysulfones o~ the
above formula wherein r and rl are zero, Rl is a
divalent connection radical of the formula:
I
R" C - R"
wherein R" is selected from lower alkyl, aryl, and
the haloge~ substituted groups thereof, preferably
methyl and R2 i5 a sulfone group.
The most preferred poly(aryl-ether)
polymers are polysulfones are those having the
general formula:
H0 ~ ~ 0 ~ - S2 ~ - ~ ~ ~ n
D-12824-1
-- 27 --
~2~709~7
Where n is ~uch that the molecular weight
of the poly(aryl ethers) used in the invention i8
preferably less than lO,OOO, most preferably less
~han 5,000.
The urea-formaldehyde resins useful in the
ccmpositions of this invention are produced from the
reaction of for~aldehyde with the -NH2 groups of
the urea. The initial base catalyzed reaction
between formaldehyde and urea produces methylol-,
dimethylol- and ~ri~ethylolureas. This reaction is
followed by condensation reactions that eliminate
water to form polymers. This mixture of low
molecular weight polymers and methyiolureas is known
as urea-formaldehy~e resin ~hich on ~.eati~g yields
insoluble, infusible, crosslinked products. The
preparative reactions are illustrated by the
idealized s~ructures depicted in the equation below:
2 2 2 > HO-CH2NH-CO-NH2 +
HO-~H2NH-CONH-CH2t)H
HOCH ~
~ N-CO-NHCH2OH
HOCH2
NH ( CH2 - N~ )
CO CO
HOCH2-~H NH
where R is CH2OH or H.
Preferab~y the urea-fcr~alde~yde resin are
free of volatile sol~ents such as water, alcohol~,
and the like.
~-12824-1
- 2B - ~ Q97
The ~ela~ine-formaldehyde resins u~eful in
th~ ~ompo~itio~6 ~f this inventi~n are produced from
the conden~tion of for~aldehyde with the ~mino
group~ ~f ~el~mine (2,4,6 -tri~ino-1,3,5- triazine)
S gener~lly ~n~er ~a~ic pH conditions. One ~le of
the ~elamine can r~act with 1-6 ~ole~ ~f
formal~ehyde yielding ~ono, di-, tri, t~tra-,
pent~-, and hexa~ethylcl~elamines. These ~ethylol
~erivatives further poly~eri2e with the eli~ina~isn
w~ter for~ing ~el~ines linked by ~ethylene and
~ethyl~ne either bridges. The r~aetion i~
illustrated by the following equ~tion:
f ~ 2 HOCH3~ NHCH2OH
~/' ~1/
~H2 NH2
~CH2NH ~ ~ HCH2NH ~ _ NHCH2OH
~aH2 hH;~CH20H
HOCH2NH ~ ~I~ NHcH2ocH2NH ~ NHCH20H
NH2 NH2
~urther condensation of the ~elamine-
~or~ldehyde recin, ~celer~ted by he~t or ~cid
D-12B24-1
,~,~
, ~
'70g7
catalyst, nnd especially when tri- to
hexamethylol~elamine derivatives are involved yields
crosslinked structure~.
Preferably the ~ela~ine-~ormaldehyde resins
are free of volatile solvents such as water,
alcohols and the like.
The thermosetti~g composition~ useful in
this invention ~re prepared by admixing the
phenol-formaldehyde resole, phenol-~ormaldehyde
0 novolac, aromatic polyester, unsaturated polyester,
aromatic polycarbonate, poly(aryl ether),
urea-formaldehyde or melamine-~ormaldehyde polymer
with the phenol hemiformal and/or ~ethylolated
phenol hemiformal in the previously described
concentrations and in a manner such that a solution
is obtained with a viscosity less than about 50~,00
centipoise and preferably less than about 10,000
centipoise, depending on the molding method to be
used. The admixture ~ay be carried out at any
suitable pressure, at~ospheric pre~sure bein~
convenient, and at a temperature of ~rom about
a~bient temperature (about 20~C) to about lOO-C,
preferably from about 60-C to about 80~C. It is
generally advantageous to agitate the ~ixture
vigorously during the preparation to facilitate
dissolution. The resultin~ mixtures comprise liquid
thermosetting compositions which are curable to
thermosets.
The liquid co~positions can be cured by the .
addition of heat. Generally, a catalyst is also
added to the composition to enhance the cure rate.
Either acids, such as sulfuric and toluene
sulfonic acid, or bases, ~uch as organic amines,
&lkali or alkaline earth hydroxides, can be employed
D-12824-1
- 30 -
~l2U7~9~7
a6 the aforeme~tioned catalyst. In general,
substances which can catalyze phenol/aldehyde
condensation reactions can be employed as the
catalyst for the ~uring reaction. The selection of
tha type and concentration of the catlyst depends on
the molding process and the cure rate desired. For
exanple, when employed in a process such as that for
sheet molding compounds, wherein the cure of ~he
molding composition i5 interrupted at some
inter~ediate ~ttage for ~torage or additional
handling, less ~ctive ca~alysts and less vigorous
curing conditions would be required. For liquid
injection ~olding or reaction injection molding
~perations where short cycle time is desired, a more
active catalyst and at a hi~her concentration is of
greater utility.
A~ong the ~cidic catalysts which have been
successfully employed are included phenol sulfonic
acid, phosphoric acid, maleic acid, chlorosulfonic
acid, toluene sulfonic acid and many others. Phenol
sulfonic acid has been found to be quite convenient
and is readily obtained by dissolving sulfuric acid
in phenol. For processes such as liquid injection
molding or reaction injection molding the preferred
catalyst is an acidic catalyst at a concentration of
about 0.2 to 5 weight percent based on the weight of
the uncatalyzed liquid composition. For processes such
as sheet molding compounds, the catalyst is preferably
a less active catalyst such as basic catalysts like
amines at a concentration of up to 10 weight percent
based on the weight of the uncatalyzed liquid composition.
The actual concsntration will depend on the activity
of the catalyst used. These catalysts and their activi-
ties in phenol/aldehyde condensation reactions are well
known in the art.
D-12824-1
--- . . .... . . ~ .. . ..
-- 31 --
~2~7~97
The preferred curing procedure wherein the
catalyst is preferably introduced to the liquid
compositions of ~hi6 invention before the curing
step may be termed a one-component ~ystem. In such
a sy~tem the catalyst level is adjusted such that
c~re is substantially avoided during handling prior
to injection into a mold. The mold is at a higher
temperature, generally greater than 80C, 50 that
the curing reaction i8 activated thermally. Once
activated the curing reaction accelerates due to
heat evolved by the exothermic reaction.
Another procedure, which may be termed a
two-component i~ystem, may be employed when one does
not wish to keep the composition containing the
catalyst in such a ~tate for very long before
injection into the mold. In such a two-component
sy6tem an acidic catalyst is introduced into a
solution of phenol and the polymer. This mixture i5
then pumped and metered into a mixing device
concurrently with and separately from the hemiformal
such that the components are mixed in the mixing
device. After mixing, the liquid composition of
this invention which contains a catalyst is injected
immediately into a mold where the cure takes place.
The liquid composi'ion of this invention
which has had catalyst added thereto, which may be
termed a liquid prepolymer, and which may be
prepared by either the one or two-component ~ystem
described above, or any other convenient method,
should have a total aldehyde to total phenol molar
ratio of from 1:1 to 2:1, preferably from 1.1:1 to
1.8:1, most preferably from 1.2:1 to 1.5:1.
By total aldehyde and total phenol, it is
meant the total amount of ~uch moieties existing as
D-12824-1
- 32 -
~Z~709~
free aldehyde or phenol or the equivalent thereof
present in the hemifor~als or the polymere in the
solution. The ratio m~y be adjusted by addition of
~ phenol, an aldehyde or additional hemiformal to
the prepolymer.
The li~uid prepolymer composition~ are
cured by the application of heat. A temperature of
from 80CC to 200-C, preferably from 120C to 160C,
is employed ~or the cure. The curing ti~e will vary
and will depend on such factors as the particular
makeup of the ~hermosetting composition, the
temperature, the a~ount to be cured, the
configuration of the cured part, and other factors
known to those in the art. Generally curin~ times
are from 1 to 15 minutes.
Suitable reinforcing materials useful in
the composites of the invention include glass
fibers, carbon fibers, graphite fibers,
wollastonite, cellulousic fibers such as wood flour
and the like, organic fiber~ ush as aromatic
polyamide ibers, and mica.
The preferred reinforcing materials are
glass fibers, graphite fibers and aromatic polyamide
fibers. These fibers may be in any form common to
the art such AS chopped fiber, mat, and woven
cloth. In injection processes the fibers may be
introduced into the thermosetting composition by
mixing therewith before injection into the mold; or
preferably, the fiber is placed into the mold and
the thermosetting composition is injected
therea~ter. In sheet moldin~ compounds the fiber
may be mixed as chopped fiber prior to the initial
cure.
Other additives may be included in the
D-12824-1
- 33 -
~Z~7097
composites of the invention. These include those
com~only u~ed in the above molding method~, ~uch as
pigments and various processing aids.
The composites of the invention show
superior physical properties and have content of
reinforcing material unobt~inable in the prior art.
Because of the reactivity and low viscoity of the
liquid thermosetting ~olution used, the composites
are easily ~ade rom conventional molding processes.
T~e following examples serve to
further illustrate the invention. They are not
intended to limit the invention in any way.
In the examples the following evaluation
procedures were employed.
Flexural Modules - ASTM D790
Flexural Strength - ASTM D790
Notched Izod - ASTM D256
Heat Distortion Temperature (HDT) (264 psi)
AS~M D648
Tensile Modulus - ASTM D638
Tensile Strength - ASTM D637
Elongation - ASTM D638
Vertical Flame - UL-94
Example 1
Methylolated phenol hemiformal was prepared
as follows: to a 5 liter reaction flask equipped
with a thermometer, ~tirrer and addition-port there
were charged 1410 srams ( 15 g-moles ) of phenol, 74~
grams of 91 mole percent paraformaldehyde (parafor~)
(22.5 g-moles formaldehyde equivalent) and 10.8
grams of zinc ~cetate dihydrate as catalyst. The
mixture was stirred and heated to 85~C for about 20
minutes. A ~ild exotherm ensued. The re~ction
D-12824-1
709~
- 34 -
mixture was m~intained at from 80 to 90C by removsl
of the external heat source ~nd by occ~sional
cooling with a water bath. After the exotherm
subsided, heat was reapplied to maintain a reaction
mixture temperature of from 80 to 9~C until a cle~r
solution was obtained; this took from Qbout 1 to 2
hours. Nuclear magnetic reson~nce showed the
product to be ~ mlxture of hemiform~ls of phenol ~nd
hemiformals of methylolsted phenol.
Eight liquid resin compositions were
prepared by dissolving various phenol-formaldehyde
resole and novolac resins in a hemiformal of
methylolated phenol. For runs 1 to 5 the hemiformal
prep~red above WRS used. For runs 6 to 8 a
hemiformsl was used that was prepared in the ssme
manner ~s above except that 659 grsms of 91 weight
percent paraform~ldehyde (equivalent to 20 moles of
formaldehyde), 940 grams phenol (10 moles) ~nd 4.7
grams of zlnc acet~te dihydr~te were uæed. The
resoles h~d an Inclined Pl~te Flow of 40-90 mm at
125C. The novolacs h~d an Incllned Plate Flow of
60-80 mm when copulverized with 9~
hex~methylene-tetremine, b~sed on the total weight
of the mixture. The Inclined Plate Flow W2S
determined by compressing ~ one-grsm semple of a
pulverized product to ~ pellet 12-13 mm in
diameter. This pellet w~s pl2ced on 8 glQSS plate
~nd heated for three minutes in ~ 125C oven. The
plste w~s then tllted to ~ 60 ~ngle ~nd hesting
continued for an additionel 20 minutes. The
distance, measured in mm, the resin travelled is
known ~s the Inclined Pl~e Flow. The Inclined
Plate Flow reflects both the melt viscosity and cure
r~te of the resin.
D-12824-1
~-r
/ :3"
'~ TAEIT-F I
.,
Formaldehyde/Phenol V1scosity
Mole Ratio Poly~er Liquid Recin Compo~itlon ~rookfield
RunIn Hemiformal Type Hemiformal ~wt ~ Polymer ~wt ~) cp~, C
1 1.5 Resole, lumps 70 30 1,500, 40C
2 1.5 Resole, lumps 60 40 5,000, 40~C
.-; , 3 1.~ Resole, lump~ 50 50 20~000, ~0C
'" ! . ' S 1.5 Resole, powder 70 30 1,15G, 50-C
., 5 l.S Resole, powder 60 40
6 2.0 No~olnc, flake~ 70 30 540, 50-C
~' 7 2.0 Novolac, flakes 60 40 1,300, 50-C
8 2.0 Novolac, flakes 50 50 6,800, 50C ~n
s
''''~' ' ' C:~
.~'.
~!
., .
-''-;''
,, :;' ,~,
~LZ~7097
- 36 -
The hemiformal was heated t~ about 50C to
70C ~nd agit~ted ~s the polymer was ~dded. In
T~ble I are shown the formaldehyde to phenol ratio
of the hemi$ormal used, the polymer type ~nd its
S form, the compRrative perc~nt~ges of the hemiform~l
snd polymer in the liquid thermosetting composition,
~nd the Brookfield viscosity of the liquid thermo-
setting composition for e~ch run.
ExamPle 2
Liquid resins prepared in Example 1 were
cured ~nd used to form reinforced composites by the
following procedure. A reactive liquid prepolymer
was prepRred by Rddin8 ~ solution of phenol and
sulfuric acld to a liquid resin of Ex~mple 1 to form
~ liquid prepolymer containing phenol sulfonic
acid. The added phenol to sulfuric ~cid welght
ratio was 9. The welght percent, of the added
phenol-sulfuric acld cst~lyst, based on the total
liquid prepolymer, is shown in Table II, as ~re the
p~rticul~r liquid resins from Ex~mple I th~t were
used. The c~tslyzed mixture w~s then chRrged into
mold cont~ining 5 fiber-glass m~t. The fiber-gl~ss
m~t was type AKM avail~ble from PPG Industries,
Inc., Pittsburgh, Pennsylv~nia. The mold was pl~ced
in ~ press and hested to curing temperature. The
temperature r~nges of the cure and the curing times
ere shown in Table II. The content of fibergl~ss in
weight and volume percent ~nd the content of
thermosets composition in the cured composites Are
also shown. In Runs 9 to 11 equ~l amounts by weight
of the resins prep~red in Runs 4 and 6 of Example l
were used.
E~ch composite was evalu~ted ~nd the
results ~re reported in T~ble III. As the results
D-12824-1
TA~L.E II
i Liquid Resin
Co~po~te ~itior~ fro~Ca~lyst Mold Temp.Cure Ti~e Fibe~glass Fibergla~ ~hermo~et
~o. Run (Wt ~) ~C~ (min, ) ~Vol. ~ ~wt. 11) ~wt.
4 0.04120-150 15 46 65 35
2 4 0.0~14û-160 14 47 66 34
3 4 0.04150 1~ 33 52 48
, 4 5 0 . 03 147-150 10 24 40 60
5, ~ 0.04150 11 ~ 36.5 63.5
;- 6 1 0.1120-150 8 q5 63.6 36.
0.1 120-15010 - 31 49 51
6 1 0 . 1 120-150~ 20 35 65
9 9 ,6 O .0412G-155 13 49 67 33
- 10 4,6 ~.04110-150 14 43 62 38
11 ~,6 û.04140-153 1~ 21 37 63
.. 12 4,6 0.0~120-150 12 21 ~Ç.4 63.6
13 4,6 0.04liO-150 16 35 53.6 46.4
s
i
TABLE III
~lexural Flexural Tengile Tensile Elongation HDT Notched Izod
Compo~te Mbdulu8 Strength Mbdulus Strength ~ C (ft-lb/in Notch)
No. (lo-6 p~i) (10 4 psi (10-4 i 10-4 i (264 p~i)
1 2.02 3.45 1.91 2.55 1.55 260 25
- 2 1.94 3.3 1.73 2.58 1.8~ 260 27
' 3 1.5 3.5~ 1.5 2.09 1.6 260 21
4 1.27 2.85 1 1.~3 1.83 260 15
5 ' l.li 2.7 1.02 1.28 1.55 26~ 15
6 1.19 2.8 1.72 2.53 1.7 260 26
~ 7 1.4q 3.37 1.23 1.71 1.6 260 la
; a 1.08 2.13 1.05 1.29 1.3 260 13
9 ~.14 3.~7 1.~9 2.71- 1.65 2S0 25
1.75 3.46 1.76 2.58 1.65 260 23
- 11 1.19 2.71 1.05 1.36 1.57 260 16 w
12 1.05 2.7 1.12 1.54 1.78 260 15
- . 13 1.27 3.27 1.45 2.29 l.g3 260 20
:
,~ ;
.,
_'
... .
-. . Q
;7~r,.
".' '
., ~
7 ~ ~
"
' ' .1 ' '
` ~'
- 39 -
~2~7097
demonstrate, the fiber-glass reinforced composite
prepared with the liquid thermosetting compositions
of this Example display excellent mechanical
properties and ~llow higher than heretofore possible
glass content.
Composites 1 to 3, 6, 9, lO and 13 show
particularly high ~lass ~ontent (Table I~) ~nd
these composites demonstrate better properties than
some of those ~ontaining a lower glass content. This
demonstrates the high-fiber content composites
contemplated ~y the present invention and the
excellent mechanical properties thereof,
particularly with respect to impact resistance.
Typically, phenol-formaldehyde resins composites of
the prior art have a notched izod impact resistance
of the order of about 1 ft-lb/in, many having an
impact resistance as low as about 0.4 ft-lb1in.
This is at least an ordex of magnitude lower than
the notched izod impact resistance of the composites
of ~he invention, as i8 demonstrated in Table III
wherein composites having an impact resistance of
from 13 to 27 ft-lb/in are shown.
Example 3
Composites were ~ade as the composites
numbered 4, 9, and 11 (Table II) made in Examples
2. These were evaluated for fire resistance using
the vertical flame test UL-94, wherein the
composites are ignited with a flame. Table IV shows
the thickness the composite tested and sum~arizes
the results ~f the fla~e ~e3t. Shown are the
extinguishing times (E.T.) and the drip for a first
burn and a second succesive burn. The extin~uishing
time (E.T.) is the time it takes for the burning
compssite to extinguish itself after the flame is
D-12824-1
40 - ~ z~7097
withdrawn. As shown by Table IV the6e times, with
one exception, are all 0, which means that these
composites ceased to burn as soon as the flame was
withdrawn. "Drip" refers to the property of some
plastics to form burning liquid drops as th~y burn.
A drip of 0 indicates that no such drops were
formed. The data ~hown i~ Table IV demonstrate a
superior flame resistance of these composites. Also
shown is the rating for each composite as defined by
the test used. A V-0 ra~ing is the highest rating
for flame resistance for the flame test used.
Example 4
Eleven liquid thermosetting composition~
were prepared by dissolving various polymers in
he~iformal compositions.
The hemiformals were prepared as follows.
(a) Preparation of a Phenol
Hemiformal. Monomeric formaldehyde was generated by
the pyrolysi6 of paraform as follows. A slurry o~
200 gra~s of commercial 95~ paraformaldehyde in 500
ml of mineral oil was charged into a 2 liter flask
which was equipped with a stirrer, thermometer, gas
inlet and outlet tubes. The mixture was heated at
120C - 140C under a nitrogen atmosphere. The
gaseous formaldehyde formed was swept by a stream of
nitrogen via heated connecting glass t~bes through a
cold trap (-20C) and then fed to 400 grams of
molten phenol. Additional paraform in 100 gram
portions was added to the mineral oil as it was
being depleted by the pyrolysis. The formaldehyde
concentration in the hemiformal was deter~ined as
~ollows. About l-1.5 grams of hemiformal was
D-12824-1
- 41 - lZtI7Q97
~tirred in ~bout 75 ml of methanol and adjusted to a
pH of 4Ø One normal (1 N) ~ydroxylamine
hydrochloride solution (75 ml), also at pH 4.0 was
added tv the ~ethanol solution and allowed to react
for about 1 hour. ~he solution was then titrated
wi~h a standarized 0.5N 60dium hydroxide to a pH
4Ø The resulting hemiformal contained the
equivalent of 34.4% formaldehyde which corresponds
to a phenol/for~aldehyde ratio of 1.6. Five other
phenol hemiformals were prepared in the same manner
as above, were similarly analyzed and found to have
TABLE IV
Composite - First Burn Second Burn
No. from Thickness E.T. Drip E.T. Drip
15Table II Imils) (sec) (sec) Rating
9 133 0 0 0 0
9 123 0 0 0 0
9 123 0 0 0 0
9 138 0 0 0 0
9 122 0 0 0 0
9 132 0 0 0 0 V-O
11 lOB O O O O
11 113 0 0 1 0
11 11~ 0 0 0 0
25 11 111 0 0 0 0
11 112 0 0 0 0
11 114 0 0 0 0 V-O
4 122 0 0 0 0
4 119 0 0 0 0
4 116 0 0 0 .0
4 118 0 0 0 0
4 97 0 0 0 0
4 102 0 0 0 0 V-O
& formaldehyde to phenol ratio of 1.75, 1.87, 1.65,
1.48, and 1.73.
(b) Preparation of a Phenol/p-Cresol
Hemiformal - Gaseous formaldehyde was generated by
the method dessribed in (a) above and was fed into a
D-12824-1
- 42 -
28709~
mixture of 54 grams of p-cresol and 141 grams of
phenol at 40 - 60~C. The hemiformal was analyzed
for formaldehyde by the ~ethod in ~a) and was found
to contain and equivalent of 34.7% formaldehyde
corresponding to a ~ormaldehyde to phenol-p-cresol
molar ratio of 1.73:1.
(c) Preparation of a Hemiformal of
Linseed Oil o Modified Phenol. Linseed Oil-modified
phenol was prepared by ~ixing together in a
three-necked flask equipped with a stirrer 69.5
grams of Linseed oil, 188 grams of phenol and 2
grams of an ncidic ion exchange resin tAmberlyst
A-15) for 4 hours at 150-C. The ion exchange resin
was then removed from the linseed oil-modified
phenol by fil~ration.
Gaseous formaldehyde was prepared as in (a)
above and fed into the modified phenol at 45-6SC.
The resulting hemiformal was analy~ed as in (a)
above and found to contain the equivalent Qf 27
percent formaldehyde, corresponding to a
formaldehyde'to modified phenol molar ratio of 1.6:1.
(d) Preparation of a Hemiformal of
Tung Oil-Modified Phenol. Tung Oil-modified phenol
was prepared by mixing together in a three-necked
flask equipped with ~ stirrer 52 grams of tung oil;
188 grams of phenol and an acid ion exchange resin
(Amberlyst A-15) for 3 hours at 100C.
To prepare the hemiformal, gaseous
formaldehyde prepared as in (a) was fed into the
modified phenol at 45-65-C. The resulting
hemiformal of tung oil-modified phenol was analyzed
as in (a) and found to contain the equivalent of 40
percent formaldehyde which corresponds to a
for~aldehyde to ~odified phenol molar ratio of
D-12824-1
. ~ .
- 43 -
~2()7097
2.7:1.
The polymers used in the thermosetting
compositions of this example were prepared and
characterized as followæ:
(e) Preparation of Unsaturated
Polyester. A solution of 2,2-dimethyl-3-hydroxy-
propyl 2,2-dimethyl-3-hydroxy-propionate t224.7
grams, 1.1 moles), fumaryl chloride (76.69, 0.5
mole~ and 150 isophthaloyl chloride ~101.5 grams,
0.5 mole) in 1 liter of anhydrous trichlorobenzene
was heated at reflux while a stream of nitrogen was
sparged through to displace the hydrogen chloride
evolved. After about 18 hours, at reflux, the
evolution of hydrogen chloride ceased; the
un~aturated polyester was recovered by evaporating
the solvent under reduced pressure.
(f) Preparation of Aromatic
Polyester. A mixture of 31.25 grams (0.3) mole) of
neopentyl glycol, 152.3 grams (0.75 g-mole of
isophthaloyl chloride and 50.76 grams (0.25 g-mole)
terephthaloyl chloride in 3 liters of anhydrous
trichlorobenzene was stirred at reflux. The
hydrogen chloride liberated was sparged from the
reaction mixture with a stream of nitrogen. When
hydrogen chloride evolution ceased, which was about
2 3 hours, 171.3 grams ~0.75 mole) of bisphenol-~
was added. Heating and sparging with nitrogen was
continued until no more hydrogen chloride was
evolved. The solution was cooled and the polyester
recovered by coagulation in methanol had a reduced
viscosity (in p-chlorophenol at 50C) of 0.2 dl/g.
The aromatic polyester thus formed had the phenol
moiety in the terminal position.
(g) The Novolac Phenolic Resin. The
D-12824-1
~Z~709~
- 44 -
novol~c resin w~s ~ commercisl resin h~ving an
Inclined Plate Flow of 60-80 mm when contQinlng 9
weight percent, bssed on the total weight of the
composition, of hex~methy~eneltr~mine.
VRrious solutions of the ~bove described
hemiformals wlth the novol~c resin in (g) were
prepared by stirring ~he hemiformal at abou~ 60 to
85C while ~dding the pulverized novol~c resin in
sm~ll portions over 15 - 30 minutes. The stirring
w~s continued until ~ solution resulted; this took
an ~dditional 15 - 30 minutes. The composition was
then cooled to room temperature.
V~rious solutions of the Above described
hemiformals with the aromstic polyesters of (f) and
the uns~turated polyester of (e) were prep~red by
vigorously stirring 319 grAms of hemiform~l ~t 60 to
70C and sdding an ~mount of polyester over 1 hour
to give solutions of the compositions shown in Table
V. Solutions h~ving two different polymers were
made by dissolving ~ppropri~te Qmounts of esch
polymer individuslly 8S described above. The
solutions were then cooled to room ~emper~ture.
In Table V ~re summarized the eleven
thermosetting composltions th~t were prep~red.
Shown ere the weight percent, b~sed on the tot~l
weight of the composition, of the specific
hemiformsls and polymers ln e~ch thermosettlng
composition.
Ex~mple 4
The eleven thermosetting compositions
prep~red in Example 3 were formulated into cured
81~ss-fiber reinforced composites.
To Compositions 9, ~nd 11 to 19
D-12824-1
,~ r
~.,
~Le v
~nlLoro~l
Co~pooltion He8l1Or~al ll ~ /phenol ~oly er
~o Iyp~ ~t ~ ~ol~ hatlo Typ~ ~t ~
g phenol 70 6 1 75 ro~t~c polre~ter 29 4
phenol 7C 1 ~7 ~roc~tlc polye~t~ 30
11 phenol 50 1 65 novol-c 50
12 phcool 66 1 1 ~ un~t polyenter 16 9S
r~ novol-c 16 95
13 phenol 66 1 1 73 un~-t polyc8ter 16.95
nGvo~c 16 95
~ 19 phenol 66 1 1 73 ncvolrc 33.5
- 15 ph2nol ~72 3 ~t ~ un ~ poly~-t~ 16.~5
p-c;e~ol 127 7 ~t t3 U 7 1 7 novol~c lb 95
; 1~ pbenol 173 t 3 50 1 6 novol~c 50
17 pAenol ~7~ 3 ~t t3
~; tung oll ~1 7 ~t ~) 50 2 7 novol~c 50
- lB pbenol ~lJ 66 1 1 6 novol~c 16 95
unn~t polye8ter
- ?
; 19 phenol l23 ~6 1 1.6 IlOVGlrC 16.95
uns-t polye8ter 16 95
,'i
.~ :
(1) cont-lns 7 ~tt ethylene glycol D vl-co lty reducer
IZ3 cont~ln~ 7 ~t t of dlethylcn~ glycol 3~ viscG~ler reducer
1 '
~ O
~ r' ' ' Ci~
i~
:''
- 46 -
~2~0~7
hexamethylenetetramine (he~a) was mix~d with the
liquid thermosettin~ compo~ition to supply
additional ~ormaldehyde and to act as a catalyst by
the release of ammonia. To Compo~ition 10 no hexa
was added, and sodium hydroxide was added as a
catalyst. The mixtures were then poured into
reinforcing glass fiber. The glass fiber was
non-woven glass fiber mat, Type AKM, available from
PPG Industries, Inc., Pittsburgh, Penn. The
mixtures were heated at about 60 to 160-C for about
15 minutes to yield a partially cured tack-free
composition (B-staged). The B-staged compositions
were then charged into a mold and completely cured.
In Table VI are sho~n that weight percent hexa or
NaOH present in the mixture, the content of glass
fiber in weight percent, the conditions of the
second curing step, the cure time and the mold
temperature.
Each cured composi~ion was evaluated using
the above cited proceedures. The results shown in
Table VII show excellent physical properties ~or
these composites. Composites of high glass content
such as those from numbers 18 and 19 show results
superior to those of lower glass content. This
demonstrates the superiority of the high-fiber
composites of the invention.
Example 5
A composition having a pasty consistency
comprising 60 grams of a phenol hemiformal-resole
liquid reactive composition made as in Example 1, 3
grams of calcium oxide catalyst, 17 grams of calcium
carbonate filler and 20 grams of chopped glass fiber
was squeezed into a sheet about 1/8 inch thick
D-12824-1
-- 47 --
~2(~7~97
TABLE: VI
~lex~ oc Na0~1 Mold Temp Cure ~ime Fiberglass
Composition twt ~) tC) tMin) ~Wt ~)
9 1.8 140-150 45 30
0.3~ 200 20 20
11 1.0 140-155 15 39
12 1.0 140-155 15 40
1~ 1.0 160 25 50
14 1.0 150 20 38
1.5 150-155 Ç0 31
16 1.0 160 30 34
1~ 1.0 140 15 30
lB 1. 0 150 25 64
19 1.0 150-155 25 57
~ NaOH cataly~t.
D-1~824-1
t,`, ' TABLE VII
~ , .
C~po~ite
Fraa Flexural Flexu~alTensile Tensile HDT Notched ~zod
Canposltion ~dulus St~eng~h Modulus 5trength C (ft-lb/ln Notch)
: No. (lo-6 p9i~ ~10-4 i (10-4 P~) (10 4 psi)(264 p~)
9 1.14 2.0 ------ ------ 260 4.3
1.~1 1.46 ---- ---- 82 6,4
11 0.96 1.7 1.42 1.1 250 8.
,,~. 12 1.1 2.61 O.9g 1.37 250 17
. 13 1.15 2.74 1.. 2 1.51 250 15
'16 0.96 2.09 0.89 1.26 250 8
~,` 15 0.78 1.~1 0.64 0.77 250 10
- '' 16 0.97 1.58 0.74 0.82 250 8
17 1.0 1.,97 0.56 0.79 ~50 10
- 18 1.16 2.06 1.~8 1.~9 250 21
,. 19 1.39 2.58 ~.29 1.69 250 21
~'' 02
, '";'
-
v,' :-
,,, C;~
- 49 - ~ ~V 7
between layers of polyethylene film ~nd then heated
at 100C for ~0 minutes in a circulating air
oven. ~The glass fiber was 1/4" chopped glass,
Type 1156 avail~ble from PPG Industries, Inc.,
Pittsburgh, Penn.) A soft, malleable sheet was
obtained which remained malleable for over 3 ~onths
storage. The completely cured composite was
obtained by compression molding at 150 to 175C for
5 minutes.
D-12824-1
