Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1993-07-19
2001-10-09
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C528S220000, C528S272000, C528S295000, C528S298000, C528S302000, C528S308000, C528S370000, C528S373000, C528S397000, C525S437000
Reexamination Certificate
active
06300424
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to the preparation of high molecular weight hyperbranched polyester and polyamide polymers. The polymers are produced by a one-step process which entails polymerizing specific monomers of the formula A—R—B
2
in such a manner that side-reactions, i.e. reverse reactions, isomerization, crosslinking, and the like are substantially avoided.
P. J. Flory,
J. Am. Chem. Soc.,
74, 2718 (1952) and
Principles of Polymer Chemistry,
Cornell University Press, 1953, pp. 361-70, discusses the theory of condensation polymerization of so-called AB
n
-type monomers wherein A and B functions condense together to form branched polymers. While theoretically such polymers should be of high molecular weight, such has not been the case in actual practice. The only specific disclosures of such polymers are obtained by (i) the Friedel-Crafts condensation of benzyl halides in the presence of a MX
3
catalyst wherein X is a halogen, (ii) the elimination metal halides from alkali metal salts of trihalophenols, and (iii) intermolecular etherification of D-glucose in the presence of dilute acids to form a soluble polyglucose. Hyperbranched polyester and polyamide polymers are not disclosed. Also, only low molecular weight polymers, i.e. less than about 1,000 daltons, were obtained.
A recent attempt at producing a poly(arylene)polymer by following Flory's theory has also resulted in a polymer having a number average molecular weight below 10,000. Kim et al.,
J. Am. Chem. Soc.,
1990, 112, 4592-3, and Kim U.S. Pat. No. 4,857,630 disclose wholly aromatic poly(arylene) polymers prepared by the homocoupling of (3,5-dibromophenyl) boronic acid in a mixture of an organic solvent and aqueous sodium carbonate along with a palladium-containing catalyst. The molecular weight of the polymer was found to depend on the organic solvent and temperature employed during polymerization and addition of additional monomer at the end of the polymerization neither increased the molecular weight nor gave a bimodal distribution. Kim et al. could not explain what causes the molecular growth of the system to stop. Only low molecular weight polymers, i.e. about 5,000 daltons, were produced. During the polymerization, only single bonds between arylene groups are formed and no polyester or polyamide polymers are disclosed or suggested.
Baker et al. U.S. Pat. No. 3,669,939 discloses condensation polymerizing other ARB
2
monomers, i.e. polyhydroxymonocarboxylic acid aliphatic compounds, but only succeeds in generating polymers with molecular weights below 4,000 daltons. While the molecular weights obtained in Baker et al. are not provided, the acid values which are provided permit the calculation thereof.
In view of the previous inability to directly prepare high molecular weight hyperbranched polymers in accordance with Flory's theory, the art is replete with multi-step procedures attempting to accomplish a similar result. For instance, Tomalia et al. U.S. Pat. Nos. 4,507,466, 4,558,120, 4,568,737, 4,587,329, and 4,737,558 disclose dense “starburst” polymers produced by allowing a polyfunctional amide core molecule to react with excess methyl acrylate in a Michel-type addition. Each arm of the resulting star-branched molecule is then reactivated to an amine-terminated moiety by exhaustive amidation using excess 1,2-diaminoethane to afford a chain extended product in which each primary amino group becomes a new branch point in the next series of Michael additions. The polymers are thus built up, layer after layer, from a core substance by selective condensation of functional groups with each successive layer becoming a core for the subsequent layer. Only aliphatic polyamides and polyethers are exemplified and the monomers used are of the A-B type.
Similarly, Denkewalter et al. U.S. Pat. Nos. 4,289,872, 4,360,646 and 4,410,688 disclose highly branched polyamide polymers produced from lysine—an A—R—B
2
monomer having one carboxy group, two amino groups, and an aliphatic body—but utilizes a multi-step process of blocking the functional groups and then unblocking them. only relatively low molecular weight polymers were produced due to the inherent difficulty in obtaining complete reaction for each of the multiple of blocking, unblocking, and reacting steps.
Copending application U.S. Ser. No. 07/369,270, filed Jun. 21, 1989, now U.S. Pat. No. 5,041,516, issued Aug. 20, 1991, of Frechet et al. discloses a convergent pathway for preparing dendritic molecules in which accurate placement of one or more functional groups on the outer surface of the macromolecules is accomplished. The convergent approach entails building the final molecule by beginning at its periphery, rather than at its core as in divergent procedures, but still requires a blocking-unblocking multi-step operation, albeit of only a single reactive group at a single focal point which avoids the prior art problem of dealing with a multiplicity of reactive groups as the molecule grows.
Extensive prior art exists on the preparation of linear aromatic polyesters derived from, for example, 4-hydroquinone and phthalic acid or derivatives thereof. Also, Kricheldorf et al.,
Polymer Bulletin
1, 383-388 (1979) discloses preparing linear aromatic polyesters by heating trimethylsilyloxybenzoyl chloride to greater than 150° C. Kricheldorf et al.,
Polymer,
23, 1821-29 (1982) discloses forming predominantly aromatic polyesters from 3-trimethylsilyloxybenzoyl chloride and incorporating small amounts, i.e. 0.6 to 16.6 mole %, of 3,5-bis(trimethylsilyloxy)benzoyl chloride to produce a few branch points. The polyesters so formed behave as predominantly linear polymers since they contain only a few potential branches while the present high molecular weight hyperbranched polyesters behave much more like individual particles.
Accordingly, the art has failed to teach a method which succeeds in producing high molecular weight hyperbranched aromatic polyester and polyamide polymers and it is an object of the present invention to produce such polymers to take advantage of their unique properties, i.e. of high polarity, low crystallinity, and lower than usual viscosity.
SUMMARY OF THE INVENTION
The present invention provides soluble hyperbranched aromatic polyester or aromatic polyamide polymers having at least 40% branching and a molecular weight of at least 10,000 and 1,00 daltons respectively, as determined by gel permeation chromatography with polystyrene calibration.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The soluble hyperbranched polymers of the present invention are derived from monomers of the formula A—R—B
2
in which R is or contains an aromatic moiety and A and B are reactive groups that (i) can take part in either an esterification reaction or an amidation reaction and (ii) yield a by-product which is gaseous at the conditions of the reaction.
Suitable aromatic moieties R for use herein include phenyl, napthyl, bi-phenyl, diphenyl ether, diphenyl sulfone, benzophenone, and the like.
Suitable A and B groups for use in preparing the hyperbranched polyesters include trialkylsilyloxy and acid halide wherein the alkyl groups contain about 1 to 4 carbon atoms and the halide is chloride, bromide, or fluoride. Specific such monomers include 3,5-bis(trimethylsilyloxy)benzoyl chloride, 5-trimethylsilyloxy-isophthaloyl dichloride, 3,5-bis(triethylsilyloxy)benzoyl chloride, 3,4-bis(trimethylsilyloxy)benzoyl fluoride, 2,4-bis(triethylsilyloxy)benzoyl bromide, and the like in which the benzoyl group is replaced with other aromatic moieties such as those above.
Suitable A and B groups for use in preparing the hyperbranched polyamides include trialkylsilylamino and acid halide wherein the alkyl groups contain about 1 to 4 carbon atoms and the halide is chloride, bromide, or fluoride. Specific such monomers include 3,5-bis(trimethylsilylamino)benzoyl chloride, 5-trimethylsilylamino-isophthalamino dichloride, 3,5-bis(triethylsilylamino)benzoyl chloride, 3,4-bis(trimethylsilylamino)benzoyl fluoride, 2,4-bis(triethylsilylamino)benzo
Frechet Jean M. J.
Hawker Craig J.
Uhrich Kathryn
Acquah Samuel A.
Cornell Research Foundation Inc.
Jacobs Bruce F.
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