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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to difunctional, low molecular weight polyisobutylene
polymers bearing terminal functional groups, their method of preparation
and use in the synthesis of block copolymers.
2. Brief Description of the Prior Art
Kennedy describes in U.S. Pat. No. 4,316,973 a class of telechelic polymers
of the general formula:
##STR3##
wherein PIB is a divalent polyisobutylene moiety and Y represents one of
the monovalent groups of the formulae:
##STR4##
These polymers have been found useful as soft segment components of
certain block copolymers. For example, the U.S. Pat. No. 4,276,394 issued
to Kennedy et al. describes the halogenated species as being usefully
incorporated into a polystyrene elastomer. Also, Wondraczek and Kennedy
described the synthesis of nylon-polyisobutylene-nylon triblock copolymers
employing the hydroxyl-terminated polyisobutylene species; see Polymer
Bulletin 2, 675-682 (1980) published by Springer-Verlag. The same
hydroxyl-terminated species was incorporated into a block copolymer of
polyisobutylene and polycarbonate; see Liao and Kennedy, Polymer Bulletin
7, pp. 233-240 (1982).
The polyisobutylene polymers of the present invention are distinguishable
from the prior art polymers described above and possess advantageous
physical properties, such as a higher degree of thermal stability, not
associated with the prior art materials.
Baldwin, in U.S. Pat. No. 3,392,154 described the desirability of obtaining
relatively low molecular weight, carboxy-terminated difunctional polymers
of polyisobutylene. However, the process described, ozonolysis of a butyl
rubber followed by oxidation or reduction of the product of ozonolysis,
apparently did not result in a difunctional, carboxy-terminated polymer as
would be evidenced by a curable mastic. As stated by Baldwin, "it is
difficult to approach the objective of two functional groups per polymer
molecule by the process of the invention when the unsaturation in the
chain is not of type II". A type II copolymer is not inclusive of
isobutylene-isoprene copolymer (butyl rubber).
By the method of the present invention, poly(isobutylene co-isoprene) or
poly(isobutylene-co-butadiene) is oxidized to obtain carboxy-terminated,
difunctional polymers, useful in a wide variety of applications.
SUMMARY OF THE INVENTION
The invention comprises a polymer of the formula:
##STR5##
wherein X is selected from the group consisting of halogen, hydroxyl and
alkoxy and n is an integer such that the polymer has a weight average
molecular weight (Mw) within the range of from 5,000 to 30,000.
The term "halogen" is used herein in its commonly accepted sense as being
embracive of chlorine, bromine and iodine.
The term "alkoxy" is used herein to mean the monovalent group of the
formula:
--O--Alkyl
Preferably alkyl is represented by lower alkyl of 1 to 4 carbon atoms such
as methyl, ethyl, propyl, butyl and isomeric forms thereof.
The polymers of the formula (I) given above are useful prepolymers in the
preparation of a wide variety of block co-polymer resins. The invention
also comprises the block co-polymers and their uses as will be detailed
more fully hereinafter. The polymers (I) are also useful as acid curing
agents for epoxy resins, employing known curing technique.
The invention also comprises a method of preparing the polymers of formula
(I), which comprises oxidizing poly(isobutylene-co-isoprene) or
poly(isobutylene-co-butadiene).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
The polymer compounds of the invention having the formula (I) given above
are telechelic, i.e., terminally functional polymers which may be
incorporated into block co-polymers through condensation co-polymerization
with reactable monomers or pre-polymers having active (labile) hydrogen
atoms. The product block co-polymers have a wide variety of uses, as will
be described more fully hereinafter.
The polymer compounds of the formula (I) given above wherein X represents a
hydroxyl group are dicarboxylic acids, useful as a diacid reactant in the
preparation of a wide variety of block copolymers which will be described
in greater detail below. The dicarboxylic acids of formula (I) may be
prepared by the method of the invention, which comprises oxidizing the
double bonds in poly(isobutylene-co-isoprene) or
poly(isobutylene-co-butadiene). The oxidation proceeds in accordance with
the schematic formulae:
##STR6##
wherein n is as defined previously, m represents an integer such that m
and n together provide the polymer of which the moiety of formula (II) is
a repeating unit, with a Mw value of from 50,000 to 500,000. Generally, m
is an integer of about one-tenth the value of n. The symbol R' in the
formula (II) represents one of hydrogen and methyl. The polymers having
repeating units of the formula (II) are well known compounds and are the
commercially available poly(isobutylene-co-butadiene) and poly
(isobutylene-co-isoprene) copolymers commonly referred to in the art as
"butyl rubber". They may be prepared by the method described in U.S. Pat.
No. 2,356,128.
The oxidation may be carried out by heating the
poly(isobutylene-co-butadiene), poly(isobutylene-co-isoprene) or mixtures
thereof in the presence of an oxidizing agent such as dichromate, alkaline
permanganate and preferably nitric acid. Advantageously the oxidation is
carried out in the presence of an inert organic solvent for the copolymer
starting material. The term "inert organic solvent" is used herein to mean
an organic solvent that does not enter into or otherwise adversely affect
the desired course of the reaction. Representative of inert organic
solvents which may be employed in the oxidation are hydrocarbon solvents
such as n-hexane, n-octane and the like. Any proportion of solvent may be
employed, preferably sufficient to dissolve the starting polymer.
In a preferred embodiment method of the invention, the starting rubber
polymer (II) is dissolved in the inert organic solvent and nitric acid is
added slowly, in a molar excess (preferably a 4 to 10 X molar excess),
with stirring of the reactants.
Although a wide range of temperature and pressure conditions may be
employed in the oxidation process of the invention, the temperature is
advantageously within the range of from about 50.degree. to 150.degree.
C.; preferably 60.degree. to 100.degree. C. The pressure employed may be
subatmospheric or super-atmospheric; preferably atmospheric.
Progress of the oxidation may be followed by employment of conventional
analytical technique. For example, disappearance of the unsaturated bonds
in the starting polymers may be followed by infra-red analytical
technique.
Upon completion of the oxidation, the reaction mixture may be allowed to
cool to room temperature, washed with water to remove residual oxidizing
agent and the desired polymers of formula (III) separated by precipitation
following conventional precipitation techniques and procedure. However, it
is not necessary that the polymeric dicarboxylic acids of the formula
(III) be isolated from the neutralized reaction mixture to be useful. The
crude product mixture may be employed, for example, to prepare the
polymeric diacyl halides and the polymeric dialkoxy compounds of formula
(I) hereinafter described more fully without first separating the
dicarboxylic acid polymer of the formula (III).
Polymer compounds of the invention having the formula (I) wherein X
represents halogen are diacyl halides, which may be prepared by reaction
of the polymeric dicarboxylic acids of formula (III) with a phosphorus
halide; see for example the general procedure described by Cloke et al.,
J.A.C.S., 53, 2794 (1931). In general, a phosphorus trihalide is employed
in molar excess over the dicarboxylic acid. In a preferred embodiment of
the invention, the halide is chloride and the diacyl chloride of formula
(I) is prepared by the action of a molar excess of thionyl chloride on the
polymeric dicarboxylic acid of formula (III), in the presence of a
catalytic proportion of pyridine and an inert organic solvent for the
compound of formula (III) as described above. The reaction is well known
and may be carried out by the method described by Ralls et al., J.A.C.S.,
77, 6073 (1955). Most preferably the catalyst is dimethylformamidinium
chloride which may be formed in situ in the reaction mixture by employing
dimethylformamide as a solvent for the thionyl chloride in an excess
proportion of about 10 percent of an equivalent of dimethylformamide to
thionyl chloride; see the method of Zollinger et al., Helv. Chim. Acta.
42, 1653 (1959).
The carboalkoxy terminated polymers of the formula (I) given above wherein
X represents alkoxy may be prepared by esterification, employing known
methods, of the polymeric dicarboxylic acids or the diacyl halides of the
formula (I) given above. For example, the esterification can be carried
out by esterifying the dicarboxylic acid or the diacyl halide of formula
(I) with an alcohol of the formula:
Alkyl--OH (IV)
wherein alkyl is as defined herein. The esterification conditions are
conventional and well known. In general, the polymeric dicarboxylic acid
(I) may be refluxed with a molar excess of the alcohol (IV) in the
presence of a mineral acid. A convenient synthesis of polymeric diester
from the polymeric diacyl halide may be carried out by the
Schotten-Baumann reaction [C. Schotten, Ber. 17, 2544 (1884)]. In a
preferred method, the polymeric diacyl halide is esterified with the
sodium alcoholate of the alcohol of formula (IV) in the presence of an
inert organic solvent as previously defined.
The polymer compounds of the formula (I) given above are telechelic and
difunctional, possessing terminal groups reactive in condensation
polymerizations (also termed "step-reaction polymerizations") to obtain a
wide variety of block copolymers. For example, as an acid reactant in
admixture with appropriate dicarboxylic acid monomers, the polymers of the
formula (I) may be co-condensed with polyols to obtain co-polyesters,
polyester carbonates and polyethers. Condensed with polymers having
condensable functional groups such as acid or hydroxyl groups, there may
be obtained block-copolymers such as block-copolymers of polycarbonates,
polyetherimides, polyarylates and the like.
POLYCARBONATE--POLYISOBUTYLENE BLOCK COPOLYMERS
Polycarbonate block copolymers of the prepolymer compounds of the invention
having the formula (I) given above may be obtained by the copolymerization
of the compounds (I) with conventionally employed polycarbonate resin
precursors. The polycarbonate--polyisobutylene copolymer product resins of
the invention so obtained comprise the polymerized reaction products of
(i) at least one dihydric phenol;
(ii) a carbonate precursor; and
(iii) a polymer compound of the formula (I).
The copolymer resin obtained may be represented by those having recurring
or repeating structural units of the formula:
##STR7##
wherein D is a divalent aromatic radical of the dihydric phenol employed
in the polymerization reaction.
The recurring or repeating units of the formula (V) are interrupted by at
least one divalent moiety of the formula:
##STR8##
wherein n is as defined previously.
The polycarbonate--polyisobutylene block copolymers of the invention may be
prepared by known, conventional methods such as is described in the U.S.
Pat. Nos. 3,028,365; 3,334,154; 3,275,601; 3,915,926; 3,030,331;
3,169,121; 3,027,814; and 4,188,314, all of which are incorporated herein
by reference thereto. In general, the preparation may be carried out by
interfacial polymerization or phase boundary separation,
transesterification, solution polymerization, melt polymerization,
interesterification, and like processes. Interfacial polymerization is
preferred.
Although the preparative processes may vary, several of the preferred
processes typically involve dissolving or dispersing the reactants in a
suitable water immiscible solvent medium and contacting the reactants with
a carbonate precursor, such as phosgene, in the presence of a suitable
catalyst and an aqueous caustic solution under controlled pH conditions.
The most commonly used water immiscible solvents include methylene
chloride, 1,2-dichloroethane, chlorobenzene, toluene, and the like. A
molecular weight regulator, i.e., a chain stopper, is generally added to
the reactants prior to or during the contacting of them with a carbonate
precursor. Useful molecular weight regulators include, but are not limited
to, monohydric phenols such as phenol, chroman-I,
para-tertiary-butylphenol, and the like. Techniques for the control of
molecular weight are well known in the art and may be used for controlling
the molecular weight of the copolycarbonate-resins of the invention.
The catalysts employed, if an interfacial polymerization technique is used,
accelerate the rate of polymerization of the dihydric phenol reactant with
the carbonate precursor such as phosgene. Suitable catalysts include but
are not limited to tertiary amines such as triethylamine, quaternary
phosphonium compounds, quaternary ammonium compounds, and the like.
The preferred process for preparing polycarbonate--polyisobutylene
copolymer resins of the invention comprises a phosgenation reaction. The
temperature at which the phosgenation reaction proceeds may vary from
below 0.degree. C., to above 100.degree. C. The phosgenation reaction
preferably proceeds at temperatures of from room temperatures (25.degree.
C.) to 50.degree. C. Since the reaction is exothermic, the rate of
phosgene addition may be used to control the reaction temperature. The
amount of the phosgene required will generally depend upon the amount of
the dihydric phenol and the amount of dicarboxylic polymer acid present,
and may be a stoichiometric proportion.
Representative of dihydric phenols which may be employed are those of the
formula:
##STR9##
wherein:
each R is independently selected from halogen, hydrocarbyl and monovalent
hydrocarbonoxy radicals;
W is selected from divalent hydrocarbon radicals, --O--, --S--, --S--S--,
##STR10##
each m is independently selected from whole numbers having a value of from
0 to 4 inclusive; and
b is either zero or one, preferably one.
Preferred halogen radicals represented by R are chlorine and bromine. The
preferred monovalent hydrocarbyl radicals represented by R include alkyl,
cycloalkyl, aryl, aralkyl, and alkaryl radicals.
The preferred alkyl radicals represented by R are those containing from 1
to about 10 carbon atoms. The preferred cycloalkyl radicals represented by
R are those containing from 6 to 12 ring carbon atoms, i.e., phenyl,
naphthyl, and biphenyl. The preferred aralkyl and alkaryl radicals
represented by R are those containing from 7 to 14 carbon atoms,
inclusive.
The monovalent hydrocarbonoxy radicals represented by R have the general
formula --OR", wherein R" has the same meaning as R (but not halogen).
Preferred hydrocarbonoxy radicals are the alkoxy and the aryloxy radicals.
The divalent hydrocarbon radicals represented by W include the alkylene
radicals, alkylidene radicals, cycloalkylene radicals, and cycloalkylidene
radicals. Preferred alkylene radicals are those containing from 2 to 20
carbon atoms. Preferred alkylidene radicals are those containing from 1 to
20 carbon atoms. Preferred cycloalkylene and cycloalkylidene radicals are
those containing from 6 to 16 ring carbon atoms.
Some illustrative, non-limiting examples of the dihydric phenols
represented by Formula VII include:
2,2-bis(4-hydroxyphenyl)propane; i.e., bisphenol-A;
2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane;
2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane;
1,1-bis(4-hydroxyphenyl)cyclohexane;
1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclohexane;
1,1-bis(4-hydroxyphenyl)pentane;
bis(4-hydroxyphenyl)methane;
bis(3,5-diethyl-4-hydroxyphenyl)methane;
1,3-bis(4-hydroxyphenyl)propane;
4,4'-thiodiphenol; and
4,4'-dihydroxy-2,6-dimethyldiphenyl ether.
The dihydric phenols which may be used in the preparation of the copolymer
resins of the invention are well known in the art and are described, inter
alia, in U.S. Pat. Nos. 3,018,365; 2,999,835; 3,148,172; 3,271,368;
2,991,273; 3,271,367; 3,280,078; 3,041,891 and 2,999,846, all of which are
incorporated herein by reference.
As a class, the most preferred dihydric phenols employed in the preparation
of the polycarbonate moiety in the polycarbonate--polyisobutylene block
copolymers of the invention are those that provide repeating or recurring
chain units of the formula (V) given above, having the more specific
formula:
##STR11##
wherein R.sub.1 and R.sub.4 are each selected from a divalent aromatic
hydrocarbon radical, a divalent, halogen-substituted aromatic hydrocarbon
radical and a divalent, alkyl-substituted aromatic hydrocarbon radical;
and R.sub.2 and R.sub.3 are each selected from the group consisting of
hydrogen and hydrocarbyl.
As used throughout this specification and claims, the term "hydrocarbyl" is
used to mean the monovalent moiety obtained upon removal of a hydrogen
atom from a parent hydrocarbon. Representative of hydrocarbyl are alkyl of
1 to 25 carbon atoms, inclusive, such as methyl, ethyl, propyl, butyl,
pentyl, hexyl, heptyl, octyl, nonyl, undecyl, decyl, dodecyl, octadecyl,
nonodecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl
and the isomeric forms thereof; aryl of 6 to 25 carbon atoms, inclusive,
such as phenyl, tolyl, xylyl, napthyl, biphenyl, tetraphenyl and the like;
aralkyl of 7 to 25 carbon atoms, inclusive, such as benzyl, phenethyl,
phenpropyl, phenbutyl, phenhexyl, napthoctyl and the like; cycloalkyl of 3
to 8 carbon atoms, inclusive, such as cyclopropyl, cyclobutyl,
cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and the like; alkenyl of
2 to 25 carbon atoms, inclusive, such as vinyl, allyl, butenyl, pentenyl,
hexenyl, octenyl, nonenyl, decenyl, undececyl, dodecenyl, tridecenyl,
pentadeceyl, octadecenyl, pentacosynyl and isomeric forms thereof.
The terms "substituted hydrocarbyl", "substituted alkyl", "substituted
aralkyl" and "substituted--hydrocarbon" radical as used herein mean the
hydrocarbyl moiety as previously defined wherein one or more hydrogen
atoms have been replaced with a specific chemical group as mentioned in
conjunction with the defined term.
The carbonate precursors useful in the preparation of the
polycarbonate--polyisobutylene copolymer resins of the instant invention
include the carbonyl halides, the bishaloformates, and diaryl carbonates.
The carbonyl halides include carbonyl chloride, carbonyl bromide, and
mixtures thereof. The bishaloformates include the bishaloformates of
dihydric phenols such as bisphenol-A, hydroquinone, and the like; and the
bishaloformates of glycols such as ethylene glycol and neopentyl glycol.
Typical of the diaryl carbonates are diphenyl carbonate and
di(alkylphenyl) carbonates such as di(tolyl) carbonate. Some other
illustrative examples of diarylcarbonates include di(naphthyl) carbonate,
phenyl tolyl carbonate, and the like.
The preferred carbonate precursor is carbonyl chloride, also known as
phosgene.
Also included herein are polycarbonate moieties which are randomly
branched. These randomly branched polycarbonate moieties are obtained by
adding a minor amount, typically between about 0.05 and 2.0 mole percent,
based on the amount of dihydric phenol used, of a polyfunctional aromatic
compound which functions as a branching agent. These polyfunctional
aromatic compounds contain at least three functional groups which may be
hydroxyl, carboxyl, carboxylic anhydride, haloformyl, and mixtures
thereof. Some illustrative non-limiting examples of these compounds
include trimellitic anhydride, trimellitic acid, trimellityl trichloride,
4-chloro formyl phthalic anhydride, pyromellitic dianhydride, mellitic
acid, mellitic anhydride, trimesic acid, and the like. The method of
incorporating branching in the polycarbonate units of the block copolymers
of the invention are known to those skilled in the art; see for example
the description in U.S. Pat. No. 4,001,184.
The relative proportion of chain units of the formula (V) and of the chain
units of formula (VI) found in the polycarbonate--polyisobutylene block
copolymer resins of the invention generally depend upon the amounts of
compounds of Formulae (I) and (VII) used in the preparation of the
copolymer. Thus, for example, if 10 weight percent of polymer (I) is used
the resin will contain about 10 weight percent of structural unit (VI) in
the polymer chain. Any relative proportion of the chain units of the
formulae (V) and (VI) may be found in the copolymer resins of the
invention. Preferably, from 0.5 to 50 weight percent of the polymer of
formula (I) is used. At the higher proportion, the copolymer of the
invention will exhibit increasing properties of elasticity as compared to
copolymers made with lower proportions of the polymer of formula (I).
The polycarbonate--polyisobutylene block copolymers of the instant
invention described above may have a weight average molecular weight of
from about 20,000 to about 200,000, preferably from about 30,000 to about
150,000 and an intrinsic viscosity, as measured in methylene chloride at
25.degree. C., of at least about 0.4 dl/gm, preferably from about 0.45 to
about 1.40 dl/gm.
The polycarbonate--polyisobutylene block copolymers of the invention are
useful as thermoplastic molding compositions. The moldable resins and
resin compositions are useful to mold a wide variety of useful articles
such as component parts of automobiles, tool housings and the like
articles by conventional molding techniques including injection molding,
solvent casting and the like procedures.
When employed as the active ingredient in a thermoplastic molding
composition, the polycarbonate--polyisobutylene block copolymers of the
instant invention may optionally have admixed therewith the commonly known
and used processing or product additives such as, for example,
antioxidants; antistatic agents; inert fillers such as glass, talc, mica,
and clay; ultraviolet radiation absorbers such as the benzophenones,
benzotriazoles, and cyanoacrylates; hydrolytic stabilizers such as the
epoxides; color stabilizers such as the organophosphites; and flame
retardents.
Some particularly useful flame retardants are the alkali and alkaline earth
metal salts of organic sulfonic acids. These types of flame retardants are
disclosed, inter alia, in U.S. Pat. Nos. 3,933,734; 3,948,851; 3,926,908;
3,919,167; 3,909,490; 3,953,396; 3,931,100; 3,978,024; 3,953,399;
3,917,559; 3,951,910 and 3,940,366, all of which are hereby incorporated
herein by reference thereto.
COPOLYESTER-CARBONATE/POLYISOBUTYLENE RESINS
Block copolymers within the scope of the invention also include the
polymerization reaction products of copolyester--carbonate monomer
precursors with the polymer compounds of the formula (I) given above.
Briefly stated the copolyester--carbonate chain units comprise recurring
carbonate groups, carboxylate groups, and aromatic carboxylic groups in
the linear polymer chain in which at least some of the carbonate groups
and at least some of the carboxylate groups are bonded directly to the
ring carbon atoms of the aromatic carbocyclic groups.
The copolyester--carbonate chain units contain ester bonds and carbonate
bonds in the polymer chain unit wherein the amount of ester bonds is from
about 25 to about 90 mole percent. For example, 5 moles of bisphenol-A
reacting completely with 4 moles of isophthaloyl dichloride and one mole
of phosgene would give a copolyester--carbonate chain unit of 80 mole
percent ester bonds.
The copolyester-carbonate-polyisobutylene block copolymer resins of the
instant invention may be derived from (i) at least one dihydric phenol of
Formula (VII) given above, (ii) a carbonate precursor as previously
described (iii) at least one ester precursor, and (iv) at least one
dicarboxylic terminated polymer of Formulae (III) as described above.
The ester precursor is a difunctional carboxylic acid or an ester forming
reactive derivative thereof. In general any difunctional carboxylic acid
or its ester forming reactive derivative conventionally used in the
preparation of linear polyesters may be used in the preparation of the
instant copolyester-carbonate-polyisobutylene resins. Generally the
difunctional carboxylic acids which may be used include the aliphatic
carboxylic acids, the aliphatic-aromatic carboxylic acids, and the
aromatic carboxylic acids. These acids are described in U.S. Pat. No.
3,169,121, which is hereby incorporated herein by reference. The preferred
difunctional carboxylic acids and their ester forming reactive derivatives
are the aromatic difunctional carboxylic acids and their ester forming
reactive derivatives. Aromatic difunctional carboxylic acids suitable for
producing poly(ester-carbonates) may be represented by the general
formula:
HOOC--R.sup.1 --COOH (IX)
wherein R.sup.1 represents a divalent aromatic radical such as phenylene,
naphthylene, biphenylene or substituted phenylene; two or more aromatic
groups connected through non-aromatic linkages such as a cycloaliphatic
group of five to seven carbon atoms, inclusive (e.g. cyclopentyl,
cyclohexyl), or a cycloalkylidene of five to twelve carbon atoms,
inclusive, such as cyclohexylidene; a sulfur-containing linkage, such as
sulfide, sulfoxide or sulfone; an ether linkage; a carbonyl group; a
tertiary nitrogen group; or a silicon-containing linkage such as silane or
silocy; or a divalent aliphatic-aromatic hydrocarbon radical such as an
aralkyl or alkaryl radical. For purposes of the present invention, the
aromatic dicarboxylic acids or their reactive derivatives such as, for
example, the acid halides or diphenyl esters, are preferred. Thus, in the
preferred aromatic difunctional carboxylic acids, as represented by
Formula (IX), R.sup.1 is an aromatic radical such as phenylene,
biphenylene, naphthylene or substituted phenylene. Some nonlimiting
examples of suitable aromatic dicarboxylic acids which may be used in
preparing the poly(ester-carbonate)polyisobutylenes of the instant
invention include phthalic acid, isophthalic acid, terephthalic acid,
homophthalic acid, o--, m--, and p-phenylenediacetic acid, and the
polynuclear aromatic acids such as diphenyl dicarboxylic acids, and
isomeric napthalene dicarboxylic acids. The aromatic dicarboxylic acid may
be substituted with an inorganic atom such as halogen; an organic group
such as the nitro group, an organic group such as R above; or an alkoxy
group; it being only necessary that the substituent group be inert to and
unaffected by the reactants and the reaction conditions. Of course, these
acids may be used individually or as mixtures of two or more different
acids.
Particularly useful difunctional carboxylic acids are isophthalic acid,
terephthalic acid, and mixtures thereof.
Instead of using the difunctional carboxylic acids as the ester precursor
it is at times preferred to utilize their ester forming reactive
derivatives. Thus, for example, instead of using isophthalic acid,
terephthalic acid, or mixtures thereof it may be preferred to use
isophthaloyl dichloride, terephthaloyl dichloride, or mixtures thereof.
The copolyester-carbonate/polyisobutylene resins of the instant invention
may be prepared by well known conventional methods. These methods include
transesterification, melt polymerization, interfacial polymerization, and
the pyridine process. Various of these methods are described in U.S. Pat.
Nos. 3,169,121, 3,030,331, 3,207,814 and 4,188,314, all of which are
incorporated herein by reference.
Particularly useful processes for the preparation of the
copolyester-carbonate-polyisobutylene resins, is the interfacial
polymerization process generally described above in relation to the
preparation of the polycarbonate--polyisobutylene block copolymers of the
invention.
It will be appreciated therefore by those skilled in the art that the
copolyester-carbonate-polyisobutylene copolymers of the instant invention
prepared by the interfacial polymerization process utilizing as the
reactants (i) at least one dihydric phenol of Formula VII, (ii) a
carbonate precursor, (iii) at least one ester precursor, and (iv) one
polymer of Formula I; contain recurring structural units of the formula
(VI) and of the formula:
##STR12##
wherein R, W, m, and b are as defined above; A and B each represent the
divalent organic moiety of the ester precursor between the two functional
groups of the ester precursor.
The relative proportions of structural units VI and X present in the
copolyester-carbonate-polyisobutylene resin will depend upon the amounts
of polymer of Formulae (I) used in the prepration of the
copolyester-carbonate-polyisobutylene resin, as described above in
relation to the polycarbonate-polyisobutylene copolymers of the invention
described above.
For example, if 10 weight percent of the polymer (I) is used in the
preparation of the copolyester-carbonate-polyisobutylene resin, and
assuming complete reaction, the product resin will contain 10 weight
percent (total) of units of formula (VI). Although any proportion of the
polymer (I) may be used to prepare the block copolymers of the invention,
it is preferred that the proportion be within the range of from 5 to 50
weight percent.
The copolyester-carbonate-polyisobutylene copolymers of this invention may
optionally have admixed therewith the aforedescribed additives to make
molding compositions.
The instant coployester-carbonate-polyisobutylenes generally have a weight
average molecular weight of from about 20,000 to about 200,000, preferably
from about 25,000 to about 150,000; and an intrinsic viscosity, as
measured in methylene chloride at 25.degree. C., of at least about 0.4
dl/gm, preferably from about 0.45 to about 1.40 dl/gm. They are useful to
mold a variety of thermoplastic articles such as automobile parts, valves
and the like.
POLYAMIDE-POLYISOBUTYLENE BLOCK COPOLYMERS
The carboxy-terminated, acyl halide terminated and ester terminated
polymers of the formula (I) given above may be polymerized with polyamines
under conventional amidization conditions to obtain block copolymers which
are useful as adhesives, binder resins for flexographic ink compositions
and as curing agents for epoxy resins. Preferred block copolymers are
obtained by the condensation of a diacid component with a substantially
equivalent proportion of an organic diamine. The diacid component may
comprise the dicarboxylic polymer acid of the formula (III) but preferably
includes as co-acids a dicarboxylic acid of the formula:
HOOC--R.sub.5 --COOH (XI)
wherein R.sub.5 represents alkylene of 1 to 20 carbon atoms, inclusive, and
optionally in addition a monocarboxylic acid of the formula:
R.sub.6 --COOH (XII)
wherein R.sub.6 is selected from the group consisting of alkyl having 1 to
20 carbon atoms, inclusive, phenyl and hydroxy-substituted phenyl. The
ratio of the moles of acid of formula (III) to the acid of formula (XI) in
the diacids mixture may be in the range of from 1-2 to 1 and the ratio of
the sum of the moles of acids of formulae (III) and (XI) to the moles of
acid of formula (XII) being from 1 to 0.0-0.08 as an example.
The term "alkylene of 1 to 20 carbon atoms" is used throughout the
specification and claims to mean the divalent moiety obtained upon removal
of two hydrogen atoms from a hydrocarbon having the stated carbon content.
Representative of alkylene of 1 to 20 carbon atoms are methylene,
ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene
and isomeric forms thereof.
The method of preparing the polyamide-polyisobutylene copolymers is a
conventional polyamide preparation, several of which are well known.
Polymerization reacts an amine group and a carboxylic acid group to form
an amide group with the concomitant elimination of water; see for example
U.S. Pat. No. 3,377,303. Other processes include solution or interfacial
polymerization. These processes are recommended to react an amine and an
acid chloride to form a polyamide with the loss of acid. A preferred
process is melt polymerization, by amine-ester interchange. A solvent may
be added, or the process may be performed without a solvent as described
in U.S. Pat. No. 4,567,249, hereby incorporated by reference.
The dicarboxylic acids of formula (XI) are well known and include
aliphatic, cycloaliphatic and aromatic dicarbocylic acids. Representative
of such acids, which may contain from 3 to 20 carbon atoms, are oxalic,
glutaric, malonic, adipic, succinic, suberic, azelaic, sebacic,
dodecanedioic and pimelic acids. Methods of preparing these acids are well
known and they are available commercially.
Preferred dicarboxylic acids of formula (XI) employed in the present
invention are straight chain aliphatic diacids having at least 6 carbon
atoms and more preferably 6 to 16 carbon atoms, such as azelaic and
sebacic acids, which are most preferred. It should be understood that use
of the corresponding acid anhydrides, esters and acid chlorides of these
acids is included in the term "dicarboxylic acid".
The monocarboxylic acids of the formula (XII) described above are also
generally well known as is their prepration. Representative of the acids
of formula (XII) are acetic, propionic, butyric, n-valeric, neopentanoic,
heptanoic, 3-ethylhexanoic, pelargonic, decanoic, undecanoic,
dineopentylacetic, tridecanoic, myristic, pentadecanoic, hexadecanoic,
heptadecanoic, palmitic, stearic, oleic, arachidic, behenic, benzoic,
salicylic and like acids. The softening points of the adhesive
polyamide-polyisobutylene copolymers of the invention are not greatly
affected by the selection of any particular monocarbocylic acid of the
formula (XII). However, use of the lower molecular weight aliphatic acids
such as acetic, neopentanoic and pelargonic acids generally results in
copolymers of the invention characterized by the highest melt viscosity
and higher tensile strengths than are obtainable when the monocarboxylic
acid (XII) is of a higher molecular weight.
The organic polyamines preferably employed in preparing the copolymers of
the present invention may be one or more of the known linear aliphatic,
cycloaliphatic or aromatic diamines having from about 2 to 20 carbon
atoms. Preferred especially are the alkylene diamines. Illustrative of the
preferred diamines are ethylene diamine (EDA), 1,3-diaminopropane,
1,4-diaminobutane, 1,6-hexamethylene diamine (HMDA),
4,4'-methylene-bis-(cyclohexylamine) (PACM), 1,20-diamino eicosane,
isophorone diamine, cyclohexanebis-(methylamines), bis 1,4-(2
aminoethyl)-benzene, piperazine (PIP) 1,3-di-(4-piperidyl-propane (DIPIP)
and 1-(2-aminoethyl) piperazine. Also preferred are the polyglycol
diamines such as Jeffamine.RTM. D-2000 available from Texaco and
polyglycol diamine H-221 available from Union Carbide Corporation. Most
preferred are the primary diamines EDA and PACM, alone or in combination
with the secondary diamines PIP and DIPIP. These diamine compounds are all
prepared by well known methods and many are commercially available.
Polyamide-polyisobutylene block copolymers useful as hot melt adhesives may
be prepared by mixing, heating and reacting the mixture of acids of
formulae (I), (XI) and (XII) with a substantially equivalent proportion of
polyamine, to produce a neutral or balanced polyamide, i.e., the acid and
amine numbers are substantially equal. By "substantially equivalent
proportion" it is meant that the total number of amine groups provided in
the reaction mixture should approximate the total number of acid groups
presented by the mixtures of acids. In practice this is accomplished by
providing a slight excess (circa 2 percent) of the polyamine in the
initial reaction mixture to compensate for the small proportion usually
lost through volatization under the conditions of the amidization
reaction. The temperature at which this condensation polymerization is
carried out is not critical, but is advantageously carried out at a
temperature of from about 100.degree. C. to about 300.degree. C.,
preferably within the range of from about 180.degree. C. to 300.degree. C.
To assist the polymerization, a polymerization catalyst may be added to
the reaction mixture in a catalytic proportion. Representative of such
catalysts is phosphoric acid.
The term "catalytic proportion" is used herein in the usual sense as
meaning that proportion which will catalyse the desired polymerization. In
general such a proportion is within the range of from about 0.001 to 3
weight percent, most preferably 0.01 to 1.0 percent by weight of the total
charge of reactants.
In addition, it is understood that small amounts of surface active
materials may be added to the poymerization to reduce foaming.
Representative of such materials are Dow Corning's DB-100, silicone
anti-foam.
It is advantageous to also include as a componenet of the polymerization
reaction mixture, an antioxidant. Any of the well known antioxidants may
be employed in conventional proportions, i.e., from 0.1 to about 2 percent
by weight of the reactants.
In order to avoid undue discoloration of the copolymer product, the method
of preparation is preferably carried out in an inert atmosphere such as is
provided by carbon dioxide, nitrogen or argon gases. During the course of
the reaction, amidization occurs with formation of water. The formed water
is advantageously allowed to distill out of the reaction mixture as the
condensation polymerization occurs. Distillation may be assisted by
allowing a slow stre | | |
