Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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~ ~ BACKGROUND OF THE INVENTION
:.. :"
, 5 It will be appreciated that copolymeric compositions
are well known, and further, that literally thousands of
such polymers have been disclosed. Additionally, copolymeric
compositions are well known where a silicone constitutes a
major and essential constituent. Within the silicone copoly-
i~ 10 mer may be either carbonate identifiable groups or ester
, identifiable groups.
With regard to the presence of a carbonate group in
a polysiloxane copolymer, attention is directed to U.S. Patent
~'l No. 2,999,845 to Eugent P. Goldberg. Simply stated, the com-
positions of Goldberg comprise dihydric phenol derived groups
linked by both carbonate and siloxy groups. With regard to
the presence of an ester group in a polysiloxane copolymer,
~¦ attention is direc~ed to U.S. Patent No. 3,701,815 to Matzner,
et al. The patentees thereof disclose therein a thermoplas-
tic siloxane-polyester block copolymer having siloxane blocks
ll that are linear and contain dihydrocarbyl~iloxane groups and
; ' polyester blocks that are linear and contain groups derived
~rom aromatic dicarboxylic acids and aromatic diols.
None of the prior art workers have disclosed the
concep-t o~ providing a thermoplastic silicone copolymer wherein
.,: .
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,~, :,,.
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",. . .
r';~
. ............................................................ ..
~.:::-,, .
::::: . . ,
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:`: ::::.: . , , . . :;: ::~::.:.: ~ : :
.: ~` .. . . . .
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there is included aromatic carbonate and aromatic ester groups
all well defined and present in specific proportions to pro-
vide materials which are capable of withstanding heat
;' sterilizlng temperatures (at least 100 C.) to permit use in
,... .
A,,,',' 5 medical equipment, yet which can also be radio frequency
dielectrically-sealed, for e~ficient and convenient manu-
~; facturing of flexible films, bags, tubing components, and the
;," ,.
-~; like made of the material.
,..................................... .
The present invention relates to this concept, i.e.
a heat-sterilizable, R.F. dielectric-sealable thermoplastic
silicone copolymer, and a method for producing it.
The organic polymer component may be crystalline or
. amorphous at the temperature of use. Consequently, at the
,
temperature of use, the copolymers are strong plastics which
may be rigid or flexible whereas at higher temperatures the
copolymer is a viscous liquid which may be fabricated by con-
ventional thermoplastic methods. The constituents in the
. .,
~, polymer, as will be seen below, may be combined in different
ratios and with varying molecular sizes with respect to the
,. . ..
constituents, so as to produce copolymers which have a wide
' range of mechanical and thermal properties, both at the use
- temperatures and at the melt fabrication temperatures.
, ,; .~
, CHARACTER:tSTICS_AND _UTILITIES OF THE INVENTION
~;?
. The copolymers of this invention will in most cases
; :.:.,
~ 25 be transparent, strong, soluble in specific solvents, and
r, ~.'
1~,.1.,'. i
~ -3-
j ,;.,,
,.....
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~,
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~i;;.......... ., . , :~
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~., .
;..,..;
~' extremely stable towardsdegradation ky heat, light, water
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IA''.. ~."~ and other chemicals.
It has been discovered that permeability of the
copolymers of the present invention depend to a considerable
degree on the nature and properties of the constituenti. For
example, it is possible to adjust the moieties of the con-
stituents whereby a resultant film may be obtained having ex-
cellent oxygen permeabilities approaching that of
poly (dimethylsiloxane), which is probably the most permeable
-~ 10 of all known non-porous solids. On the other hand, the con-
.," .~
stituents may be adjusted to achieve a copolymer having a
~; low degree of permeability to oxygen, perhaps even lower than
plasticized polyvinylchloride of comparable flexibility. As
a result, this wide range of permeability to small molecules
such as 2~ N2, C02, or H2O, permits the copolymer of the
~`l present invention to be useful for a wide range o applications.
Some of the copolymers may be employed in the fabrication of
~,~ containers (i.e., barriers to permeation~ whereas others are
i-~ useful as separators ~i.e., selective permeation).
Usually, the copolymers may be subjected to steam
~'
sterilization at a desirable temperature of about 120~ C. with-
:. .:,,
out undue distortion or loss of clarity or leaching.
These copolymers generally are not affected by polar
and hydrogen-bonding solvents, such as ethyl alcohol, water,
glycerol, dimethylsulfoxide or dimethylformamide. On the
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other hand, these same copolymers may be dissolved and cemented
together or with other materials by solvents such as
chlorinated aliphatics (e.g. methylene chloride, chloroform,
l,l,l-trichloroethane), aromatic hydrocarbons and ~heir
chlorinated derivatives (e.g., toluene, benzene, xylene,
naphthalene, chlorobenzene, orthodichloro-benzene, 1,2,4-
trichlorobenzene) ketones (e.g., methyl ethyl ketone, acetone~
~yclohexanone), and ethers (e.g., tetrahydrofuran, 1,2-
dimethoxyenthane, diphenyl ether).
It will be readily apparent to those skilled in the
art that these copolymers are especially useful for medical
applications in which they contact biological fluids or tissues,
or drugs which are to be administered intravenously or other-
wise. The copolymers have been found to be stable, non-toxic,
non-leaching ~i.e., showing a lack of migration o chemicals
from the copolymer), and compatible with biological matter
(e.g., blood fractions, whole blood, tissues). Such applica-
tions include especial]y containers for blood and blood compo-
nent collection, transfer and storage ~at minus 196~ C. or
higher temperatures); tubing accessories (e.g., filters, con-
nectors) for transfer of intravenous solutions; manifolds and
other units of artificial organs ~e.g., blood oxy~enators,
blood heat exchangers, membrane kidney, blood pumps, heart
assist devices), bubble-type blood oxygenators and accessories
(tubings, connectors, spargers, defoamer sponge, urinary
.
. . . ~ _ _ .
..
l~SS6~L
drainage Foley catheters, contact eye lenses, organ support
devices (e.g.0 kidney and liver containment and fluid cir-
culation), various surgical de~îces (e.g., blood suction,
filtration and transfer), plastic syringes (e.g., pre-filled
syringe cylinders, plungers and seals), membranes for ex-
change of oxygen and carbon dioxide in artificial lungs, and
controlled diffusion of drugs from delivery systems to patients.
SCOPE OF THE INVENTION
The-present invention is concerned with thermoplas-
tic silicone copolymers having poly (diorganosiloxane) compo-
nents which are covalently bonded to condensation type organic
polymer components. This is accomplished so that these two
polymer components are connected in an end-to-end relationship
in an alternating manner.
Generally, the compounds of this application may be
prepared by: reacting one molar part of a diorganopQlysiloxane
having hydrolyzable endgroups with more than 2 and less than
10 molar parts of a dihydric phenol;
reacting the resulting product with a difunctional
organic acid halide, to produce polyester moieties at each
end of the polysiloxane by chain-forming reaction between the
remaining dihydric phenol and the difunctional organic acid
halide; the organic acid halide being present in less than a
stoichiometric quantity sufficient to react completely with
said dihydric phenol; and
1055G41
thereafter reacting the resulting product by gradual
addition of an organo carbonate precursor, the polysiloxane
being present in the final product in the amount of 45 to 60
percent by weight, and having a molecular weight of 300 to
3,000, preferably about 500 to 1200, and,when bisphenol A
and terephthalic acid halide is exclusi.vely used, in their
respective functions, from 700 to 1,000.
The mole ratio of the difunctional organic acid to
the organo carbonate precursor is generally from 1/2 to 9/1,
the numerator in each case reflecting the moles of difunctional
organic acid present and the denominator indicating the moles
.of organo carbonate precursor present.
It is generally preferred for the mole ratio of the
difunc-tional organ.ic acid and the organo carbonate precursor
to be from about 1 to 1 to about 5 to 1. It is generally
pxeferable to keep the ratio below 5/1 when the molecular
weight of the silicone component is at the high~r end of the
range, particularly greater than 1200, if both good sterilizing
temperature strength and R.F. sealability is desired in the
plastic product. When the silicone molecular weight is 2000
or greater, the above ratio is desirably about 1/1 to 3/1.
Similarly, it is pxeferable for the total amount of
polysiloxane present in the final product to be no more than
about 50 percent by weight when higher molecular weight
polysiloxane materials are used, i.e. having a molecular
/ ~ ~
1~556~L~
weight of over about 12~0,
The copoly~er of the present invention may be pro-
duced by several process variations. They may be produced
~y reaction in solution between the difunctionarly reactive
5 silicone, dihydric phenol and an oryano diacid halide, with
or without a catalyst r or an alkyl or aryl ester of organo-
diacid using a transesterification catalyst. When a con-
stituent is an organodiacid halide, the preferred catalyst
is pyridine or a trialkylamine, Useful transesterification
catal~sts for the purposes herein intended are tetrabutyl-
orthotitanate, magnesium or its oxide, antimony oxide, stannous
octate, or dialkyl tin alkylates.
Recovery and purification of the product copolyme~
is ef~ected by precipitation of the copolymer in a nonsolvent,
lS such as methanol, ethanol, isopropanol or acetone when an
organodiacid halide has been employed as one of the constit-
uents. When one of the constituents has been an alkyl or aryl
ester of an organodiacid, precipitation reco~ery is applicable
or the solvent may be evaporated while the catalyst is de-
activated by exposure to heat, water vapox, oxy~en or other
suitable reactant depending on the nature of the catalyst.
It is also within the purview of the invention to
obtain copolymerization wherein the reagents are in a molten
condition. In such a melt method the resultant copolymer is
obtained by cooling thç reaction mixtuxe and deactivating the
~\ .
1~5564~
c~talyst ~y conventional well known means such ~s by expo~
~ure to urther he~tr w~ter vapor~ oxy~en or the other
reactantsr depending on the nature of the catalyst,
~ny dihydric phenol compound capable of~a polycon-
5 densation type reaction is useful in the practice of this
invention~ such dihydric phenol being clefine~ as a monoaryl
ox polyaryl phenol type material in which the hydroxyl groups
are attached directly to aromatic rinq carbon atoms, The di-
hydric phenol compounds used in connection with the invention
can typicall~ be represented by the general formula,
~IO_ ~ ~ p } ~ ~m ~
where R is hydrogen or a monovalent hydrocarbon radical, for
example, alkyl radicals (e.g., methyl, ethyl, propyl, isopropyl,
butyl, decyl, etc.), aryl radicals (e.g., phenyl, naphthyl,
biphenyl, tolyl, xylyl, etc.), aralkyl radicals (e.g., benzyl,
ethylphenyl, etc.), cycloaliphatic radicals (e.g., cyclopentyl,
cyclohexyl, etc.~, as well as monovalent hydrocarbon radicals
containing inert substituents therein, such as halogen ~chlorine,
bromine, fluorine, etc.). It will be understood that where
more than one R is used, they may be alike or different. R2
is selected from the group consisting of an alkylene or alkylidene
residue such as methylene, ethylene, propylene, isopropylidene,
_g_
.. , ~
. , ~ .. .. . . . . .
~"` 105S641
butylene, butylidene, isobutylidene, amylene, isoamylene,
amylidene, isoamylidene, cyclohexylidene, etc. R2 can also
be a silane radical or can be polyalkoxy, such as polyethoxy,
polypropoxy, polythioethoxy, polybutoxy, polyphenylethoxy,
etc. R2 can also consist of two or more alkylene or alkylidens
groups such as above, separated by an aromatic group, a tertiary
amino group, an ether group, a carbonyl group, silane radical
or siloxy radical, or by a sulfur-containing radical such as
~ulfide, sulfoxide, sulfone, etc. R2 may also be a dibasic
acid ester residue derived from, for example, dibasic acids
such as adipic, azelaic, sebacic, isophthalic, terephthalic
and alkyl or aryl glycols and dihydric phenols. Other groupings
which can be represented by R2 will occur to those skilled
in the art. A is the residue of an aromatic nucleus, Y is a
substituent selected from the group consisting of (a) inorganic
atoms, (b) inorganic radicals, and (c) organic radicals, (al,
~b), and (c) being inert to and unaffected by the reactants
and by the reaction conditions, m is a whole number inc~uding
zero to a maximum equivalent to the number of replaceable
nuclear hydrogens substituted on the aromatic hydrocarbon
residue, p is a whole number including zero to a rnaximum de-
termined by the number of replaceable hydrogens on R2, s
ranges from 0 to 1, t and u are whole numbers including zero.
When s is zero, however, either t or u may be zero, and not
both.
In the dihydri~ phenol compound, the substituents Y
--10--
1~556~
may be the same or different as may be the R~ Among the sub-
stituents represented by Y are halogen ~e.g., chlorine, hro-
mine, fluorine, etc.) or oxy radicals of the formula OW,
~here ~ is a monovalent hydrocarbon radical simirar to R, or
monovalent hydrocarbon radicals of the type represented by R.
Other inert substituents such as a nitrol group can be repre-
sented by Y. Where s is zero in Formula I, the aromatic
nuclei are directly joined with no intervening alkylene or
alk~lidene or other bridge. The positions of the hydroxyl
groups and Y on the aromatic nuclear residues A can be varied
in the ortho, meta, or para positions and the groupings can
be in a vicinal, asymmetrical or symmetrical relationship,
where two or more of the nuclearly bonded hydrogens of the
aromatic hydrocarbon residue are substituted with Y and the
lS hydroxyl ~roup. Examples o~ dihydric phenol compounds that
may be employed in this invention include
2,2-bis~(4-hydroxyphe~yl)-propane (i.e., bisphenol-A); 2,2
bis~4-hydroxy-3,5-dichlorophenyl-propane (i.e.~
tetrachlorobisphenol-A); 2,4'-dihydroxydiphenyl-methane;
bis-~2-hydroxyphenyl)-methane; bis~(4-hydroxyphenyl)-methane;
bis-(4-hydroxy-5-nitrophenyl)-methanei bis-(4-hydroxy-2,6-
dimethyl-3-methoxyphenyl)-methane; 1,1-bis-(4-hydroxyphenyl)-
ethane; 1,2-bis-(4-hydroxyphenyl)~ethane; 1,1-bis-(4-hydroxy-
2-chlorophenyl)-ethane; 1,1-bis-2,5-dimethyl-4-hydroxy-phenyl)-
ethane; 1,3-bis-(3-methyl-4-hydroxynaphthyl)-propane; 2,2-bis-
. ~ , ",
: ' ~
1~55Çi4~
(3-phenyl-4-hydroxyphenyl)-propanei 2,2-bis-(3-isopropyl-4
hydroxyphenyl)-propane; 2,2-bis-(4-hydroxynaphthyl)-propane;
2,2-bis-(4-hydroxyphenyl)-pentane; 3,3-bis-(4~hydroxyphenyl)-
pentane; 2,2-bis-(4-hydroxyphenyl)-heptane; bis= (4-hydroxy-
phenyl)-phenyl methane; bis-(4-hydroxyphenyl)-cyclohexyl
methane; 1,2-bis-(4-hydroxyphenyl~ 1,2-bis-tphenyl)ethane;
2,2-bis-(4-hydroxyphenyl)-1,3-bis-(phenyl) propane; 2,2-bis-
(4-hydroxyphenyl)-1-phenyl propane; and the like. Also in-
cluded are dihydroxybenzenes typified by hydro-~uinone
and resorcinol, dihydroxydiphenyls such as 4,4'-dihydroxy-
diphenyl; 2,2'-dihydroxydiphenyl; 2,4'-dihydroxy-diphenyl;
dihydroxy-naphthalenes such as 2,6-dihydroxynapthalene, etc.
Dihydroxy aryl sulfones,such as those set forth in U,S. Patent
No. 3,269,986 are also useful, e.g., bis-(4-hydroxyphenyl)-
sulfone; 2,4'dihydroxy-diphenyl sulfone; S'-chloro-2,4'-
dihydroxydiphenyl sul~one; 5'-chloro-2', 4,4'-dihydroxydiphenyl
sulfone; 3'-chloro-4,4'-dihydroxy-diphenyl sulfone; bis-(4-
hydroxyphenyl) biphenyl disulfone, etc~ The preparation of
these and other useful sulfones is described in Patent 2,288,282 -
Huissmann. Polysulfones as well as substituted sulfones using
halogen, nitrogen, alkyl radicals, etc., are also useul.
Dihydroxy aromatic ethers are also useful~ Methods of pre-
paring such materials are found in Chemical Reviews, 38,
414-417 (1946), and Patent 2,739,171 - Linn. Exemplary of
such dihydroxy aromatic ethers are 4,4'-dihydroxdiphenyl
-12-
9556~
ether; 4,4'-dihydroxy-triphenyl ether; the 4,3'-4,2'-,2,2'-,
etc. dihydroxydiphenyl ethers; 4,4'-dihydroxy-2,5-
dimethyldiphenyl ether; 4,4'-dihydroxy-2,6-dimethyldiphenyl
ether; 4,4'-dihydroxy-3,3'-di-isobutylialiphenyl ~ther, 4,4'-
dihydroxy-3,3'~diisopropylidiphenyl ether; 4,4'-dihydroxy-
3,2'-dinitrodiphenyl ether; 4,4'-dihydroxy-3,3'-
dichlorodiphenyl ether; 4,4'-dihydroxy-3,3'-difluorodiphenyl
ether; 4,4'-dihydroxy-2,3l-dibromodiphenyl ether; 4,4'-
dihydroxydinaphthyl ether; 4,4'-dihydroxy-3,3'-dichlorodinaphthyl
ether, 2,4'-dihydroxytetraphenyl ether; 4,4'-dihydroxypentaphenyl
ether; 4,4'-dihydroxy-2,6-dimeth-oxydiphenyl ether; 4,9'-
dihydroxy-2,5-diethoxydiphenyl ether, etc. Mixtures of the
dihydric phenols can also be emplo,yed, and where dihydric
phenol is mentioned herein, mixtures of such materials are
considered,to be included. Also, the dihydric phenol materials
can be utilized herein in conjunction with aliphatic diols
such as ethylene glycol or propylene glycol.
The alkyl siloxanes useful in conjunction with this
invention are those in which the alkyl groups attached to the
'20 silicon atom are methyl, ethyl, halomethyl, haloethyl, or
mixtures thereof and in which the reactive groups are pre-
ferably halosilanes, the reactive groups numberiny two per
molecule. The aryl siloxanes preferred are those in which
the aryl group is phenyl or halophenyl with, again, the reac-
tive groups being preferably halogen and numbering two per
~L~55Çi9L~
molecule, Alkyl aryl siloxanes axe also useful. It is well
known that the lower alkyl groups ancl the phenyl groups im-
part greater heat stability to silicone materials; hence,
these materials and particularly dimethylpolysiloxane are
pre;Eerred. However, up to about twenty-five percent of ma-
terial containing other than methyl, ethyl or phenyl groups
or dexivatives thereof can be tolerated without serious loss
of heat resistance, including alkyl groups containing from
two to five or more carbon atoms. Also~ 3,3,3-
trifluoropropylmethylsiloxane groups improve the oil resis-
tance otE the polymer.
~hile Eor best results and low cost the hydroly~able,
reactive groups on the ends should be siiicon-bonded halogen,
other reactive groups such as alkoxy, amino, aryloxy, and
acyloxy can be used~ ~dditionally, other reactive end groups
on the silicones include alkyl hydroxyl, alkyl acid halides,
and aromatic acid halides. While the preferred silicon-
bonded (i.e., attached to Si by C--Si linkages) methyl and
phenyl groups can be present in any proportion , when phenyl
is used, it is preferred to have :Erom about 40 to 60 percent
methyl groups with the rest phenyl. The exact proportion to
be used will depend on the particular properties desired in
the final product. While both methyl and phenyl groups are
superior in heat resistance, an excessive amount of either
group tends toward a b~ittle product at very low temperatures
-14-
5s6~
~- while an excess of phe~yl groups causes high rigidity at alltemperatures. The above prescribed proportions result in an
end product which has the most desirable combination of
! physical properties.
Also, silicone-organic derivatives can be used as
the diorganopolysiloxane ingredient, as shown in Example 3
below.
While for best results and from the s-tandpoint of
availability and low cost, the halosilane groups are prefer-
ably chlorine, the other halides - bromine, iodine, fluorine -
may also be employed.
Suitable difunctional organic acid halides include,
for example, those derived from phthalic, isophthalic,
terephthalic, polynuclear aromatic such as diphenic and
naphthalic, sulfonyl dibenzoic and carbonyl dibenzoic acids.
Also useful are difunctional organic acid halides derived
from hydroxy acids and phosgene, such as derived from hydroxy
benzoic and hydroxy naphthalic acids. Carbonate precursors
which are suitable include phosgene and its bromine and iodine
Z0 analogs (i.e., the carbonyl dihalides) as well as the
bishaloformates of dihydric phenols (e.g., bischloro-formates
of ethylene glycol, neopentyl glycol, polyethylene glycol,
etc.). Other carbonate precursors will occur to those skilled
in the art.
While phosgene is the preferred reagent, suitable
~. . .: . ~ ..
~.
~SS64~L
phosgene-like dibasic acid halides may be employed, such as
dibromo and diiodocarbonyls.
The following examples are int~ended to be illustrative
of the present invention.
EXAMPLE 1
Preparation of a 50~ Silicone~600Mn)-Poly
Bisphenol-A TerePhthalate Carbonate) Seqmented
Copolymer Using a Bischlorosllane Silicone
Dry bisphenol-A (i.e., 4,4'isopropylidene diphenol)
in an amount of 570 grams (2.5 moles) immersed in
dichloromethane (7 liters) in a reaction vessel was spargea
air-free by dry oxygen-free nitrogen. Trimethylamine in an
amount o 300 grams ~5 moles) was metered into the mixture
as it was gently agitated.
The trimethylamine which functions catalyticallv was
added through the sparge tube which was immersed below the
liquid surface. The resultant was a clear liquid solution.
; ~ - dichloropoly(dimethyl-siloxane)-in an amount of 600
grams (1 mole) was added to the aforesaid solution while ac-
companied by rapid agitation. The resultant at this juncture
was a clear, non-viscous solution which was warmer due to the
exothermic reaction of the reagents.
Thereafter, terephthaloyl chloride in an amount of
228 grams (1.125 moles) dissolved in air-free dichloromethane
(0.5 liter~ was added over a period of about 10 minutes to
-16- -
,
~S564~L
the rapidly agitated reactor, resulting in a clear non-viscous
solution, warmed by the exothermic reaction of this added
reagent.
The resultant material was then subjected to slow
agitation for a period of one hour. The resultant material
in this period of time becomes slightly more viscous While
accompanied by an increase in agitation, phosgene gas in an
amount of 37.5 grams (.375 moles~ was metered into the reac-
tion mixture through the sparge tube over a period of one
hour. The final 1~ percent of the phosgene was added at only
10% of the initial rate in order to assure a slow approach to
the end point of the reaction. This diminution of the rate
of addition of the phosgene gas assures that the final product
will possess high molecular weight with good strength charac-
teristics.
During the phosgene addition, the reaction mixture
contained and further developed precipitated crystals of
trimethylamine hydrochloride salt, which does not interfere
with the reaction process and which occurrence results in
less contamination of copolymer by salt during isolation of
the copolymer from the final reaction mixture. Furthermore,
during the phosgene addition the reaction mixture became pro-
gressively more viscous and more rapidly so during the final
10% of the phosgene addition. When the viscosity of the
reaction mixture attained a predetermined high value, the
17
'
~55641
phosgene addition w~5 stopped and the reactions were ter-
minated by adding a small amount of isopropyl alcohol,
approximately 1 to 2 grams (.017 to .033 moles) over a
period of 5 to 10 minutes until no phosgene could be detected
in the nitrogen sparging through the reaction mixture and out
of the reactor. Tha final reaction mixture wa5 a viscous
solu~ion of copolymer containing dispersed crystals of
trimethylamine hydrochloride salt.
The resultant copolymer was precipitated, i.e.,
isolated from the reaction mixture by filtration then slow
addition to a 15-fold volume of methyl alcohol while the
alcohol was rapidly agitated. The copolymer precipitated as
relatively small, short fibers whereas the alcohol sol~biliYes
all unreacted reagents and by-products. The resultant copoly-
mer was easily filtered from the alcoholic solution. It was
washed with several volumes of fresh alcohol. The copolymer
was then dried in a vacuum oven at 100 - 130 C. for 1-3 hours.
The dried copolymer (over 90% of the theoretical yield) con-
sisted of colorless small particles which were compression
m~lded and extruded at 180 - 300~ C. to become relatively
coloxless transparent, flexible a~d strong fabricated articles.
The copolymer contained 50% by weight silicone ~soft component)
and 50% by weight polyester-polycarbonate block copolymer
~hard component) in which the mole ratio of ester ~and acid
halide) to carbonate ~as 3:1 ~i.e., the hard component consists
-18-
~, ~"~,
, ~ .
- 1~556~3~
of 75 mole percent bisphenol terephthalate and 25 mole percent
bisphenol carbonate, approximately) as determined by nuclear
ma~netic resonance spectroscopy,
EXAMPLE 2
.
Preparation o~ a 60~ Silicone(1462Mn) Pol
(Bisphenol-A Terephthe ~ te rSeqmented
Copolymer Using a Bischlorosilane S~licone
This example differs from Example 1 regarding the
silicone ~olecular weight and content in the copolymer, the
ratio of terephthalate to carbonate, the type of solvent, and
several procedural details.
. Dr~ bisphenol-A (150.1 grams) was wei~Jhecl and
; qu~ntitatively transferred in air to a 1 liter measuring fun-
nel attached to a 5 liter reaction flask. Dry technical
grcde tetrachloroethane (850 ml) was added to the bisphenol A
and this mixture was sparged by dry, air-free nitrogen ~or
about 3 minutes to remove aix. Dry analytical reagent grade
pyridine ~162 ml) was added to this mixture and sparging con-
tinued for about 5 minutes, producing a clear, nearly colorless
solution, which was added to the attached reaction flask.
Into the same funnel was measured tetrachloroethane
(500 ml) and about 325 gm. of a 4, ~ -bischloro
poly(dimethyl~iloxane), having a number average molecular
weight ~Mn) of 1462, (0,222 Mole) as determinea by titration
--19--
'' : : . ', ' '
55641
of t~e chlorine end groups. This clear colorless solution
was sparged b~ nitrogen for 5 minutes to remove dissolved air,
then added to the rapidly agitated reactor over a period of
36 minutes. Subsequentlyr after 24 minutes ~f slow agi~ation
of the reactor, 990 mls of a dry and air-free solution
consisting of terephthaloyl chloride (79~3 grams) in
tetrachloroethane was added to the reactor over a period of
31 minutes, while a~ain rapidly agitating the reactor. Then
after 29 mir.utes of slow agitation~ phosgene gas was spargèd
into the bottom of the reaction mixture over a period of
2 1/2 hours, while agitating rapidly, until unreacted phosgene
; ~as detected over the reaction mixture and the reaction mix-
ture became much more Viscous than it was before phosgene
addition. Unreacted phosgene was detected by suspending in
the reactor vapor exhaust port an indicator paper prepared by
soaking a filter paper strip in a carbon tetrachloride solu-
tion of equal weights of diphenylamine and p-dimethylamino-
benzaldehyde (according to the test described in the Merck
Index, eighth edition, page 823)r
The viscous clear reaction mixture was then poured
slowly into 7 gallons of methanol agitated rapidly, which pre-
cipitated the copolymer product in the form o~ small diameter
short fibers, but which dissolved and extracted from the co-
j polymer the pyridinium hydrochloxide byproduct and the
tetrachloroethane solvent. The copolymer precipitate was
-20-
:
.1 .
:
: .. . . . . . : ~ ,
... . . . .. . .
556~
.
- recovered b~ filtration r rinsed with several portions of
methanol~ and vacuum dried 2 hours at 120 C. ~opolymer
yield was 454 grams, containing 60 wt.~ silicone and a 9:1
mole ratio ~f terephthalate to carbonate~
The white fluffy copolymer was compression molded
at 285-295C. to very strong, flexible, clear, colorless
sheets.
~ separate portion of the flu~fy copolymer was ex-
truded at 280~-300C. to form smooth, very strong, flexible,
clear colorless sheeting and tubing.
Tensile tests (ASTM D882) of the compression molded
and the extruded sheetings (3 samples each provided the fol-
lowing data;
~ _ __
Molded Extruded
... ~ ~ ...... .... _ _
I Ultimate Tensile (psi) 1226-1493 1350-1650
Ultimate Elongation (%) 310-400 420-460
Modulus at 100~ Elongation (psi) 640-800 693-906
I ear ~ropagatlon Resistance (pli, Die B) 173-213 156-187 ¦
Sheets o~ this copolymer were heat sealed together to -
give strong bonds between the sheets.
Extraction of the extruded and molded copolymer by hot
petroleum ether (b p. 30-60C.) for 16 hours removed only
3-3.5~ of the sample weight, with no.discernible difference
~21-
-'' ' , :,
SS~l
between extruded and molded samples in spite of their severe
swelling during extraction. This severe treatment demonstrates
the high extent of conversion of the reagent silicone to high
molecular weight copolymer, which is not soluble in hot
petroleum ether, and it is evidence that the copolymer is
stable during extrusion at high temperatures.
This material can be fabricated into bags and other
articles which can be steam sterilized at 120 C. without sig-
nificantly losing tensile strength.
Tubing and sheets of this copolymer were cemented
together very strongly by solvents such as methylene chloride,
1,1,2,2-tetrachloroethane, methyl ether ketone, and toluene.
However, due to the high molecular weight of the silicone
portion of the polymer, and due to the very high ratio of
terephthalate to carbonate, the material does not seal well
by radio frequency, dielectric means~
A similar material can be prepared by the above
technique which has improved radio frequency dielectric sealing
characteristics, when the above bischlorodimethylpolysiloxane
is replaced with an equal weight of a similar material having
a molecular weight of 800.
EXAMPLE 3
ration of a 25~ Silicone, 25~ Poly(ethylene
Ether), (Bisphenol-A Terephthalate Carbonate)
Segmented Copolymer Using a Silicone Biscarbinol
Using essentially the same procedures as Example 1,
1~556~L1
bisphenol-A (15.52 grams) in a glass reaction vessel was dis-
solved by adding 18.1 ml. pyridine and 125 ml~ dichloromethane
to provide a clear colorless solution. To this solution was
added 250 ml. of a dichloromethane solution containing 25 ml.
(0.011 Mole) of a silicone bis-carbinol having a number aver-
age molecular weight o~ 2270. This sil:icone biscarbinol
has a molecular structure consisting of a central segment of
, ~ -bis(3-propoxy)-poly-(dimethylsiloxane) covalently
bonded to end segments of dihydroxy-poly-(ethylene ether)
wherein the poly(dimethylsiloxane) derivative constitutes
50 u~ of the molecule, as illustrated below:
~H3 ~H3
( 2C~12O)X(CH2)3( io)y~i(cH2)3(ocH2cH2)xoH
! ~H3 CH3
This structure was verified by prior analysis by nuclear
magnetic resonance spectroscopy. To this mixture at room
temperature was added about 200 ml. of a solution of
terephthaloyl (7.6 grams) chloride dissolved in
dichloromethane. After one hour of gentle agitation at room
temperature, 1150cc of phosgene gas was sparged into this
reaction mixture over a period of about 2 1/2 hours, resulting
in a slightly viscous clear colorless solution, having a re-
acted terephthalate/carbonate ratio of 1.25/1. This solution
was poured into 7 liters of methanol to obtain a white pre-
cipitate of the copolymer product, which was filtered and
-23-
.
- .: , , . . -.
:, ,
,. ~
'~ ~
1~556~
washed with fresh methanol, then dried 2 hours at 105C.
Copolymer yield was 36.2 grams (79.6% of th~oretical). This
material compression molded at 165C. into a .015 inch thick
sheet was clear and stxong, having tensile test results as
follows: 920 psi ultimate tensile stress, 250% ultimate
elongation, and 260 psi tear propagation strength. Its duro-
meter hardness was 91 shore A. This copolymer was stiffer,
harder and stronger than equivalent copolymers which did not
contain polyether segments. It is heat-sealable by radio
frequency dielectric techniques.
EXAMP~E 4
Preparation of a 50 wt.~ Silicone CoPolYmer
Derived from d~ ,~JLDichloropol~tdimethylsi~oxane)
of 516Mn, a 1:1 Mole Ratio of Resorcinol to Bisphenol-A
and a ~:1 Mole Ratio of Terephthaloyl Chloride to Phosgene
Resorcinol ~5.33 gxams), bisphenol-A (11.06 grams),
and dichloromethane ~600 ml.) in a one-liter reactor were
sparged air-free by nitrogen, then dissolved by adding
pyridine (30 ml.). A solution (250 ml.) containing about
25g. of ~ ,~3 -dichloro-poly(dimethylsiloxane), having an
average molecular weight of 516, in dichloromethane was added
to this reactor over a period of 15 minutes, while rapidly
agitating the reaction mixture at room temperature. After
12 more minutes, to the resultant clear solution was added
a solution (150 ml.) of terephthaloyl chloride (7.85 grams)
in dichloromethane over a period of 18 minutes. Thereafter
the reaction solution was heated at reflux for one hour, and
-2~-
. ' ' ' ~.
. ~' . " ' ' ,
~ ~L055641
then left to cool to xoom temperature for 54 minutes. Then
phosgene gas (650cc) was sparged into the bottom of the re-
actor over a period of about 2 hours, after which excess
phosgene was detected in the vapors exiting from the reactor
and the reaction mixture was a slightly viscous clear color-
less solution of approximately 900 ml. volume. The copolymer
was isolated and purified by pouring this reaction mixture
into 6 liters of methanol, filtering, and rinsing with methanol
and vacuum drying as described in the previous examples. The
copolymer yield was 33.8 grams of colorless small fibers.
Compression molding this copolymer at 400F. produced
a nearly clear very flexible soft (78 Shore A hardness),
odorless, strong, tear resistant sheet. Tensile test results
for triplicate samples of this molded copolymer sheet are
tabulated below:
Ultimate Tensile Stress ~psi) . . . . . . . . . . . 1152-1319
Ultimate Elongation (~) . . . . . . . . . . . . . . 638-670
Modulus at 100% Elongation (psi). . . . . . . . . . 304-359
Tear Propagation Resistance (pli, Die B). . . . ~ . 170-189
The apparent softening temperature of this copolymer
was about 130C. Sheets of this copolymer were heat sealed
very well, by radio frequency dielectric techniques.
EXAMPLE 5
Preparation and Properties of a 55 Wt.~ Silicone
Copolymer Derived fromJ~ Dichloropoly
(dimethYlsiloxane) of 2375 Molecular Weiqht,
4:1 Mole Ratio of 1,4~Butanediol to.Bisphenoi-A, and
a 10:1 Ratio of Terephthaloyl Chloride, and Phosgene
Into a one-liter reactor bisphenol-A (5.77 yrams),
. . i ,, . . , , :
1~556~
dichloromethane ~500 ml.), and pyridine (9.2 ml.) was added
to obtain a clear solution. To this was slowly added a solu-
tion (264 ml.~ of 25 g. of a dichlorodimethylpolysiloxane
(molecular weight 2375) and terephthaloyl chloride (13.93
grams) in dichloromethane, over a period o 16 minutes. Af-
ter 1 hour there was added a solution ~102 ml.) of 1,4-
butanediol (6 ml.) and pyridine (11 ml.) in dichloromethane,
over a period of Ç4 minutes. During these reactions, the
temperature in the reactor was maintained at 21.5-26.5C. At
the end of these reactions there was a 20% theoretical excess
of butanediol over the equivalence point of the reactants,
thereby presumably producing copolymers whose ends are ter-
minate~ by butanol groups.
Isolation of a portion o the copolymer from this
reaction mixture, using the methods described in previous
examplesl indicated the yield was 78.5% of the theoretical
amount of copolymer. The copolymer isolated at this stage
molded at 395F. was translucent, colorless and very w~ak,
with a softening temperature of 150C.
The reaction was continued by sparging phosgene
(150cc) into the rapidly agitated reaction solution over a
period of 68 minutes, after which the reaction solution was
much more viscous and there was indication of the presence
of excess phosgene in the reactor. Isolation of copolymer
at this stage, by the usual precipitation and drying methods,
-26-
,
'. . ~ , '
~' , . ' ' ' '~
.
^`` 1~SS64~L ,
indicated a copolymer yield of 88.5% of the theoretical. This
copolymer molded at 390-420F. as a sheet which was nearly
transparent, strong (ultimate tensile stress approximately
1000 psi), very flexible, sealable by dielectric heating, and
had a softening temperature of 175C. These much~improved
properties clearly demonstrate the necessity of the final phos-
gene addition and the consequent fo~mation of carbonate linkages
in the copolymers. The addition of from 10 to 90 mole percent
alkylene diol, as a partial substitute for the dihydric phenol,
can permit longer polymer blocks to improve tensile strength
without loss of the capability for R.F. dielectric sealing.
In the further practice o$ the present invention and
by way of illustrating additional examples, the bisphenol-A is
replaced by an equivalent molar amount of resorcinol. Such a
procedure will yield copolymers which have similar properties
and stabilities, but which may be based on even lower molecu-
lar weight reactive silicones. It has been discovered that the
resulting copolymers will respond in an excellent manner to
dielectric heating equipment. It is also appropriate to re-
place only a portion of the bisphenol-A with resorcinol.
In the examples, the bisphenol-A is replaced wholly
or in part by one or more of the following: phenolphthalein,
hydroquinone, 2-methylresorcinol, 2,5-dimethylhydroquinone, or
other dihydric phenols such as those well known in prior prac-
tice of polycondensation reactions.
At the same time and in other examples, or in the
first mentioned example, the terephthaloyl chloride is re-
placed by isophthaloyl chloriae. In yet another embodiment
-27-
l~S56i41
only a portion of the terephthaloyl chloride is replaced.
In still other examples, the terephthaloyl chloride is re-
placed in part or wholly by succinoyl chloride or adipoyl
chloride as well as other organic diacid halides,~i.e., those
that are well known in the prior art with regard to
polycondensation reactions of the type contemplated herein.
As will be appreciated, the catalyst trimethylamine
which enters into the reac-tion to some extent is replaced in
some of the examples by other trialkylamines, such as
triethyltripropyl tributyl-amines; or by pyridine derivatives,
such as 2,4,6-dimethyl-pyridine, 2,6-dimethylpyridine, 4-
methoxypyridine, 2,6-dimethyl-pyridine, 2,6-dimethyoxypyridine,
4-dimethylaminopyridine; or by other aromatic heterocyclic
amines, such as ~uinoline and its derivatives.
While a considerable number of applicable siloxanes
were set forth in the above, the reactive poly(dimethylsiloxanes)
found most useful in carrying out the concepts of the invention
have molecular weights ranging from approximately 300-3,000.
Partial replacement of methyl in these silicones by ethyl or
phenyl produces improved low temperature flexibility, oxida-
tive stability and strength of the resultant copolymers.
With regard to the solvents it is within the purview
of the present invention to replace the methylene chloride
by other solvents which are not reactive in the process and
which act as solvents to the reagents and may or not dissolve
-28-
.
:; . :. ., , .., . . ~
: . . . . ., :
:~556~
the resultant copolymers. Alternate solvents include halo-
genated aliphatics, such as chloroform, 1 r l-dichloroethane,
l,l,l-trichloro-ethane, 1,1,2,2-tetrachloroethane, halogenated
aromatics,such as chlorobenzene, 1,2-dichlorobenzene, 1,2,4-
trichlorobenzene, aromatic hydrocarbons, such as benzene,
toluene and xylene; ketones such as acetone/ methylethyl
ketone and cyclohexanone; and ethers, such as tetrahydrofuran
and 1,2-dimethyloxethane. The choice of solvent depends on
the composition and structures of copolymer and reagents em-
ployed, consequently, perhaps not all the solvents enumeratea
will be as efficacious with regard to all the alternative co-
polymers mentioned.
EXAMPLE 6
Preparation o~ a 50~ by Weight Silicone Copolymer
Derived FromdC,~J-Dichloropoly(dimethylsiloxane)
Having a Molecular Weight of 850 and 50~ by Wei~ht
of Bisphenol-A Terephthalate and Carbonate, With
a 1/1 Mole Ratio of Terephthalate to Carbonate
By procedures similar to those described in Example
1, 400 ml. of methylene chloride, 20 ml. of pyridine, and
18.8g. of bisphenol-A were placed in a reactor and mixed.
Twenty-five grams of the polydimethylsiloxane were added in
the form of 230 ml. of a methylene chloride solution, slowly
over a period of 25 minutes, to insure the presence of a large
excess of bisphenol-A through the reaction, to increase the
yield of copolymer comprising aimethylpolysiloxane units
~. - . , , . , '
"
-
~556~
terminated at each end with a separate bisphenol-A unit
having a free end reactive hydroxyl group.
Thereafter, phosgene was slowly bubbled through the
reaction mixture over a period of 45 minutes, with a total
of 750cc of phosgene being added. After the 45 minutes, ex-
cess phosgene was detected over the reaction mixture.
The resulting copolymer exhibitled a softening tempera-
ture range of 125-160C. as measured on a Fisher-Johns
melting hotplate. The polymer was molded at 175C. to make
a strong flexible generally transparent sheet. The sheet
material was found to be sterilizable in steam at 120~C.
without flowing or adhesion to itself or the container in
which it was held. Films of the copolymer were easily heat-
sealed using radio freauency dielectric techniques to give
strong bonds. The dielectric sealing apparatus used com-
prise a pair o~ brass electrodes measuring 1/4 inch by 4
inches of contact area with a three kilowatt generator set
at a 70 percent power output, the sealing impulse being less
than 7 seconds.
EXAMPLE 7
Preparation of a 50~ Silicone (Molecular
Weight 824) Poly(Bisphenol-S Terephthalate
Carbonate) Seamented CoPolymer in Which the
Mole Ratio of Terephthalate to Carbonate is 3/1
Into a reactor'-was placed 50.ml. of methylene chloride,
15 ml. of pyridine, and 14.7g. of a dihydric phenol known as
-30-
: , .' . ~ ' . . ' ' . .
,
1~55~4~
bis-phenol-S ~4,4'-bis(hydroxyphenol) sulfone~.
To this mixture was added as a 100 ml. solution in
methylene chloride, 20g. of ~ ,~J -dichloropolydimethysiloxane
having an average molecular weight of 824.
After reac~ion was complete, 100 ml. of methylene
chloride solution containing 5.25g. of terephthaloyl chloride
was added. Thereafter, phosgene was bubbled through the re-
actor until the reaction was complete and excess phosgene
was detected over the reaction mixture.
The resulting product was an extremely viscous co-
polymer which could be molded at 410F. as a hazy white sheet,
and which was strong and flexible. The sheet was readily
sealed by R.F. dielectric heat sealing, and was steam steri-
lizable at 120C. without becoming adhesive or distorting.
EXAMPLE 8
Preparation of 50 Wt.~ Silicone Copolymer Derived
Fro ~ ,~~Dichloropolydimethylsiloxane Having a
Molecular Weiqht of 896 and 50% by Weight of
Bishpenol A Terephthalate and Carbonate With a
4:1 Mole Ratio of Terephthalate to Carbonate
:
This experiment used procedures similar to those
described in Example 1. To a reaction vessel was added 570g.
o~ dichlorome~hane, 18.7 ml. of pyridine, and 17.65g. of
bisphenol A. Twenty-five grams of the polydimethylsiloxane
described above were the~ added slowly until the reaction was
complete, followed thereafter by the addition of 8.02g. of
-31-
, ' . .; , : . :, . ' .';, ,' . ~ . ' ' , '. ., ~:'
~5564~L
terephthaloyl chloride.
Phosgene was then bubbled through the reaction mix
ture until the reaction was complete.
After separation of the resulting copolymer from the
solvent, the copolymer was molded to form a transparent
flexible sheet which was capable of dielectric R.F. heat
sealing, and survived steam sterilization without undue soft-
ening for 40 minutes at 120C.
.. . . . . . .
"'; ' ' ' ~ ' ' ' ' ~ ! '
