Note: Descriptions are shown in the official language in which they were submitted.
q~
-- 1 --
IMPROVED ARO~ATIC POLYFORMALS
BRIEF SUMMARY OF THE INVENTION
Technical Field
The present invention is directed to novel
aromatic polyformals and to the preparation
thereof. The aromatic polyformals have utility as a
molded plastic material, adhesive, sealant and the
like.
Background of the Invention
Polyformals based on Bisphenol-A were first
reported by Barclay, U.S. Patent No. 3,069,386.
They were made by reaction of the anhydrous disodium
salt of Bisphenol-A with one equivalent of
bromochloromethane in dimethyl sulfoxide. More
recently, Hay, et al, in a recent presentation
entitled "Synthesis of New Aromatic Polyformals", at
the 1982 Fall ACS Meeting in Kan~as City, Missouri,
addressed their manufac~ure.
German Offen. 2,738,962, May 11, 1978,
describes the manufacture of aromatic polyformal
resins in which the units have structure
-- OROCH2 -- and wherein R is an arylene of 6 to
30 carbon atoms and the resin has an intrinsic
viscosity of about .3 dl/g, measured in chloroform
at 25C. They are prepared specifically from
Bisphenol-A, an excess of methylene halides~ and
an alkali metal hydroxide.
German Offen. 2,819,582, published
September 27, 1979, describes flexible, film-forming
polyformals having the repeating structure:
CH3 i.~ 7~l
~ CH3
which are manufactured by the reaction of one mole
of ~isphenol-A and at least a stoichiometrically
equivalent amount of methylene halide in the
presence of at least a stoichiometrically equivalent
amount of an alkali metal hydroxide and a phase
transition catalyst, with or without a dipolar
aprotic solvent. This patent publication appears to
correspond to the Hay et al ACS publication.
Disclosure of the Invention
The present invention is directed to novel
aromatic polyformals comprising from about 20 weight
percent to 100 weight percent of repeating units (I)
having the formula
CH3 CH3
- O ~ S ~ O - (I)
3 CH3
and from 0 weight percent to about 80 weight percent
of repeating units SII) having the formula
~Y) (Y)
~ Rl ~ O - (II)
in which the repeating units (I) and the repeating
units (II) are connected by interbonding units (III)
having the formula
-CH2- SIII)
wherein Y is selected from alkyl groups of 1 to 4
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- 3 - ~ 9~
carbon atoms, clllorine or bromine, each z,
independently, has a value of from 0 to 4 inclusive,
n has a value o:E 0 or 1, and Rl is a divalent
saturated or unsaturated aliphatic hydrocarbon
radical, particularly an alkylene or alkylidene
radical having from 1 to 6 carbon atoms, or a
cycloalkylidene or cycloalkylene radical having up
to and including 9 carbon atoms, O, CO, SO2, S or a
direct bond.
The novel aromatic polyformals of this
invention can be terminated by end capping units
(IV) having the formula
OR2 (IV)
bonded to the interbonding units ~III) and/or end
capping units (V) having the formula
-R3 (V)
bonded to the repeating units (I) and/or (II),
wherein R2 and R3 are monovalent organic alkyl
radicals having from 1 to about 8 carbon atoms,
cycloalkyl having from about 5 to about 10 carbon
atoms, aryl containing not more than about 3 aromatic
rings, and R3 can further be an alkyl acyl,
cycloalkyl acyl or aryl acyl radical.
The present invention is further directed
to a process for preparing aromatic polyformals
comprising from about 20 weight percent to 100
weight percent of repeating units (I) having the
formula
D-13 842
CH3 CH3 ~2~
-O ~ S ~ - O~
CH3 CH3
and from 0 weight percent to about 80 weight percent
of repeating units (II) having the formula
O ~ ~ Rl ~ O (II)
in which the repeating unit~ (I) and the repeating
units (II) are connected by interbonding units ~III)
having the formula
-CH2- (III)
wherein Y is selected from alkyl groups of 1 to 4
carbon atoms, chlorine or bromine, each z,
independently, has a value of from 0 to 4 inclusive,
n has a value of 0 or 1, and Rl is a divalent
satùrated or unsaturated aliphatic hydrocarbon
radical, particularly an alkylene or alkylidene
radical having from 1 to 6 carbon atoms, or a
cycloalkylidene or cycloalkylene radical having up
to and including 9 carbon atoms, O, CO, SO2, S or a
direct bond, with the proviso that when Rl is SO2
then repeating unit III) is not the same as
repeating unit (I), which process comprises reacting
the alkali or alkaline earth metal salts of
repeating unit tI) and, optionally, repeating unit
(II) with at least one dihalomethane compound in
amounts sufficient to form the aromatic polyformal.
Detailed Description
This invention involves the manufacture of
new aromatic polyformals by the interreaction of
; D-13,842
~ ..
l7~9~
bisphenol compounds which give repeating units ~I)
and repeating units ~II) having the formulas
described above. Such bisphenol compounds include
bi s- ~ 3,5-dimethyl-4 hydroxyphenyl) ~ulfone, and
optionally 2,2-bis-~4~hydroxyphenyl) propane
~"Bisphenol A") and/or bis-~4-hydroxyphenyl)
sulfone, which are reacted in the amounts defined
with a dihalomethane to produce the aforedescribed
aromatic polyformals of this invention. More
particularly the invention is achieved by the
reaction of the aforementioned bisphenol compounds
in the presence of an amount of an alkali metal base
sufficient to theoretically form at least the
dialkali metal salt of the aforementioned bisphenol
compounds. Preferentially, the polymers are
produced in the presence of a solvent for the
monomers and the resulting polymer.
Suitable bisphenol compounds which give
repeating units (II) having the formula described
above, in addition to 2,2-bis-(4-hydroxyphenyl)
propane (3isphenol A) and bis-(4-hydroxyphenyl)
sulfone, include bis-t4-hydroxyphenyl) methane,
2,2-bis~4-hydroxy-3-methylphenyl) propane,
4,4-bis-(4-hydroxyphenyl) heptane, 2,2-bis-(3,5-
dichloro-4-hydroxyphenyl) propane,
2,2-bis-(3,5-dibromo-4-hydroxyphenyl) propane, and
bis-(3-chloro-4-hydroxyphenyl) methane~ Other
bisphenol compounds are also available and are
disclosed in U.S. Patents 2,999,835, 3,028,365 and
3,334,154.
The polymers of this invention can be
formed in a number of ways. The methods which are
employable can generally be classified as either a
two-step process or a one-step process.
D-13,842
7.Cl~
The two-step process involves a first step
of reacting slightly less than a molar equivalent of
dihalomethane with the hydrated disodium or
dipotassium salt~s) of bis-~3,5-dimethyl-4-
hydroxyphenyl) sulfone alone or with bisphenol
compounds which give repeating units (II) having the
formula described above, for example, Bisphenol A
and/or bis(4-hydroxyphenyl) sulfone, in the
proportions desired, in a highly polar solvent such
as a dimethylsulfoxide, then adding an azeotropic
solvent, such as benzene or toluene, with a small
amount of a base and, finally, dehydrating by
azeotropic distillation. In the second step another
portion of dihalomethane is added to give a slight
excess, about 1 to 5~, over stoichiometry which on
reaction causes marked increase in the viscosity of
the polymer. It is believed that the excess amount
of dihalomethane is required to make up for
hydrolysis of the polymer or evaporation losses of
dihalomethane during the manufacture of the
polymer. In the first step a low molecular weight
polymer is formed, te-rmed herein an "oligomer", and
the second step advances the polymerization of the
oligomer by reaction of the oligomer with
dihalomethane.
The one-step approach involves mixing the
polar solvent and the salt of the bisphenols, as
aforedescribed, to form a solution and dehydrating
the solution before the addition of the
dihalomethane. This one-step process is
advantageous in that an excess of dihalomethane is
not essential for high molecular weight polymer
formation. The polymers made in this manner are
invariably thermally stable, where as polymers made
D-13,842
~ ;218'7.~
by the two-step process may, with the application of
heat, increase in molecular weight or even partially
gel, presumably as a result of side-reactions o~
by-product methylol groups.
Another method which can be ernployed in
preparing the aromatic polyformals of this invention
involves mixing and heating in the polar solvent the
bisphenols, essentially 2 equivalents of an alkali
and/or alkali earth metal hydroxide and a large
excess of the dihalomethane compound as
aforedescribed in the absence of an azeotropic
solvent.
The terminal units of the polymer, -O-R2
and -R3, are formed by the addition of chain
stoppers that are mono-hydroxy organic compounds
mono-halogenated organic compounds and or organic
acyl compounds, respectively, to the reaction
mixture. Examples of suitable mono-hydroxy
compounds are hydroxy-aromatics such as phenol,
cresol and the like. Examples of suitable
mono-halogenated organic compounds include
mono-halo-alkan`es such as methyl chloride,
chloroethane, isopropyl chloride, methyl bromide,
cyclohexyl chloride and the like, and
mono-halo-alkyl-aromatics such as benzyl chloride,
benzyl bromide, and the like, and alkyl or aromatic
aryl halides such as acetyl chloride, benzoyl
chloride and the like.
The polyfoxmals of this invention can have
high molecular weight, indeed, molecular weights
characterized by a reduced viscosity of at least
about 0.2 dl/g as determined in chloroform at 25C
.5 gram per 100 cc).
The process of this invention is carried
out in the presence of highly dipolar solvents, such
as dimethylsulfoxide (DMSO), dimethylformamide
(DMF), dimethylacetamide (DMAC), N-methylpyrrolidone
- D-13,842
12~a~
~NMP~, dimethylsulphone, diphenylsulfone, sulfolane
~tetramethylenesulfone), glycol ethers such as
diglyme, triglyme, tetraglyme, and the like, and
arylethers, such as diphenylether.
Dihalomethanes, such as methylene chloride,
reac~ rapidly in the aforementioned solvents, in
particular in dimethylsulfoxide, with the salts of
the bisphenols, bis-(3,5-dimethyl-4-hydroxy-
phenyl)sulfone, optionally with bisphenol compounds
which give repeating units (II) having the formula
described above, for example, 2,2-(4~hydroxyphenyl)
propane and/or bis-(4-hydro~yphenyl)sulfone, to
readily achieve high molecular weight polyformals.
The salt form of the bisphenols can be that of any
of the alkali metals or alkali earth metals, for
example, sodium, potassium, cesium/ and rubidium,
calcium, magnesium, and the like. The alkali metal
salts are the most preferredO
The temperature of the reaction is not
critical, although temperatures of at least about
25C are believed desirable to achieve any
appreciable reaction. To achieve a reaction within
a commercially reasonable period of time, a
temperature of at least 50C is desirable.
Generally, temperatures of at least 60~-70C are
employed for polymer formation. It is oftentimes
desirable to operate the polymerization reaction
over a temperature varient which is commensurate
with the degree of polymerization sought. Thus, as
higher molecular weight polymers are desired, the
temperature can be ever increased to achieve the
same.
One of the problems with increasing
temperature, of course, stems from the degradation
~g
D-13,842
~L2~L~37~.
of the solvent at those temperatures. In the
preferred embodiment, a solvent which is stable at
the reaction temperatures employed i8 used.
However, should the solvent not be as ~table as one
desires at the ternperatur~ required to achieve the
desired molecular weight, then a second and more
heat stable solvent or polymer solvating agent
should be added. For example, in this way, one can
start with a relatively active but thermally
unstable solvent for low molecular weight
polymerization, introduce a second solvent which is
less active at the initial temperature but has a
better stability at higher temperatures, to advance
the molecular weight to the desired levelO Indeed a
third solvent can be introduced which is even higher
boiling and more stable than the second solvent in
order to maximize the level of polymer molecular
weight formation. Illustrative is the solvent
sequence of dimethylsulfoxide, followed by
sulfolane, followed by diphenylsulfone or
diphenylether, and the like.
In some instances, the molecular weight may
not be obtainable by actually redissolving the
polymer. The same aforementioned solvents can be
used for the same purpose by solvating the polymer,
that is swelling it sufficiently without actually
dissolving it to allow the polymer to react further,
at higher temperatures, and thereby advance in
molecular weight.
The process pressures are not narrowly
critical. Pressures ranging from subatmospheric to
superatmospheric pressures are employable. For
example, subatmospheric pressures may be desirable
to enhance condensation conditions while
D-13,842
~ 7~
superatmospheric conditions may be desirable for
advancing the molecular weight of already
polymerized materials.
EXAMPLES
Example 1
Into a 250 ml flask equipped with a
mechanical stirrer, reflux condenser and nitrogen
inlet was charged 45.90 g (.15 moles) of
bis-(3,5-dimethyl-4-hydroxyphenyl) sulfone, 50 ml of
methylene chloride, and 70 ml of
N-methyl-2-pyrrolidone (NMP). The mixture was
stirred under nitrogen until a homogeneous solution
is obtained. At this point 12.3 g ~.31 moles) of 97
sodium hydroxide pellets were added. The resulting
mixture was stirred at room temperature for 1 hour
and then heated to 70DC. A heavy white precipitate
formed after 1 hour. ~he viscous mixture was diluted
with 50 ml of ~MP and heated to 100C. After 24
hours at 100C the reaction was diluted with 148 ml
of chlorobenzene, cooled to room temperature and then
filtered. The resulting polymer was isolated by
coagulation in methanol and then dried in a vacuum
oven overnight a~ 60C. ~ts reduced viscosity in
chloroform (.5g/lOOcc) was .30 dl/g.
Example 2
In a flask, equipped with stirrer, reflux
condenser, thermometer and dropping funnel is placed
76.50 g. Bis-(3,5-dimethyl-4-hydroxyphenyl)
sulfone (0.25 moles)
57.00 g. Bisphenol-A tO.25 mole)
300 cc dimethylsulfoxide (DMSO)
76.7 g. 52.16~ NaOH (1.0 mole)
~ ~()~
D-13,842
~12~
under nitrogen atmosphere. This mixture is heated
wlth ~tirrlng to 70 and a solution of 39.5 g.
CH2C12 ~0.465 mole) in 30 cc DMSO added over 1/2
hour. Thereafter, the temperature i~ maintained 1/2
hr. each at 70-75~, 75-80, 80-85, 90-95 and
115-120. A Dean-Stark trap filled with benzene is
then inserted below the condenser and there is added
to the reaction mixture 70 cc. benzene and 1.65 cc.
65% NaOH ~34.6 mmol) and the water in the mixture is
azeotroped off. The mixture is cooled to 90-95 and
a solution of 3.61 g. CH2C12 (.0425 mole) in 20 cc.
DMSO (Ratio CH2C12:Bisphenols is 1.015) added over
1/2 hr. The mixture is then kept at 95-110 for 1
1/4 hr. during which time the viscosity increases
appreciably. 5 mmole each of phenol and sodium
phenate are added and heating continued 1/2 hr. at
110~ to insure complete reaction~
The polymer solution is pouxed out into a
beaker and allowed to cool and filtered. The
polymer is isolated via coagulation in methanol.
The product is dried in a vacuum oven overnight at
50-60.
Example 3
30.60 g bis-(3,5-dimethyl-4-hydroxyphenyl)
sulfone (0.1 mole)
22.80 g. Bisphenol-A (0.1 mole)
15.~5 g. 52.3~ NaOH (.202 mole)
22.14 g. 51.2~ KOH t.202 mole)
100 cc of DMSO
30 cc Toluene
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are mixed under nitrogen and the water distilled off
by azeotropic reflux. The mixture is cooled to
85-90 and a solution of 17.0 g CH2C12 (0.2 mole)
in 20 cc DMSO added over 80 min. The temperature is
raised to 90-95C for 1/2 hr. and 100C for 1/4 hr.
The viscosity of the mixture is quite high. Five
mmol of potassium phenate is added and the mixture
heated 1/2 hr. at 110C then allowed to cool to room
temperature. The polymer is isolated by coagulation
in methanol. The polymer is filtered and dried in a
vacuum oven at 60C.
Example 4
Example 2 is repeated except that 91.20
grams of Bisphenol-A (.40 moles) and 30.60 grams of
bis-(3,5-dimethyl-4-hydroxyphenyl)sulfone (.10
moles) are employed instead, and the resulting
polyformal is a tough film forming material.
D-13,842
