Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2001-07-31
2003-04-01
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S271000, C528S272000, C528S288000, C528S313000, C528S315000, C528S332000, C528S335000, C528S336000, C528S363000, C528S422000
Reexamination Certificate
active
06541599
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the manufacture of hyperbranched polymers, and polymers made by such process. Specifically, the present invention relates to a practical polymerization process for the manufacture of hyperbranched polyamides in water, and hyperbranched polyamides made from such process employing aliphatic multifunctional monomers and specific ratios of amine to carboxylic acid groups.
BACKGROUND OF THE INVENTION
Polyamides represent one of the most important groups of polymers with excellent heat and flame resistance and high tensile strength and modulus. Branched polymers and copolymers have attracted considerable attention over the past decades, since many advanced materials with new or improved properties can be obtained therefrom. The terms “hyperbranched” and “highly branched” used herein with respect to branched polymers are intended to designate polymers having a relatively high percentage of propagated branching sites per number of polymerized monomer units, e.g. at least one branching site per every ten monomer units, preferably at least one branching site per every five monomer units and more preferably at least one branching site per every three monomer units. Highly branched polymers can be made by multi-step or one step processes. Multi-step generation processes were exemplified by Frechet in U.S. Pat. No. 5,041,516 and by Hult in U.S. Pat. No. 5,418,301. Both patents described that the highly branched polymers known as dendrimer or “starburst polymer” were made through a series of growth steps consisting of repeatedly reacting, isolating, and purifying.
One-step process was first conceptualized by Flory (J. Am. Chem. Soc., 74, p2718 (1952)) who demonstrated by theoretical analysis that a highly branched and soluble polymers could be formed from monomers comprising the structure AB
2
, where A and B are reactive groups, by one-step condensation polymerization. In contrast to the dendrimers, the polymer formed by AB
2
polymerization is randomly branched. Most AB
2
type monomers, however, are not commercially available, and access to such monomers accordingly involves synthetic efforts, which is potentially problematic, especially on a large scale. To cope with such problem, one-step process for formation of a highly branched polymer may also use an A
2
+B
3
approach. In A
2
+B
3
polymerization, di- and tri-functional monomers are reacted together. For ideal A
2
+B
3
polymerization, intramolecular cyclization must be minimized as a competing and chain terminating process during polymer propagation, all A groups and all B groups should have near equal reactivity in both the monomers as well as the growing polymers, and the A and B groups should have exclusive reactivity with each other. In view of such requirements, relatively few specific combinations of A
2
+B
3
polymerization schemes have been proposed.
With regard to the synthesis of hyperbranched polyamides from AB
2
-type monomers, Kim reported the synthesis of hyperbranched aromatic polyamides from sulfinyl amino acid chloride derivatives in organic solvents (J. Am. Chem. Soc., 114, 4947 (1992)). U.S. Pat. No. 5,514,764 disclosed preparation of hyperbranched aromatic polyesters and polyamides by a one-step process of polymerizing a monomer of the formula A—R—B
2
where R represents an aromatic moiety. U.S. Pat. No. 5,567,795 disclosed synthesis of highly branched polymers in a single processing step by using branching aromatic monomers and an end-capping monomer. With regard to A
2
+B
3
polymerization, Jikei et al (Macromolecules, 32, 2061 (1999)), e.g., has reported synthesis of hyperbranched aromatic polyamides from aromatic diamines and trimesic acid. Copending, concurrently filed, commonly assigned U.S. Ser. No. 09/919,390 is directed towards the synthesis of novel highly branched water soluble or dispersible polyamides using, e.g., an A
2
+B
3
or AB
2
approach by condensation polymerization of multifunctional monomer reactants comprising amine and carboxylic acid functional groups, where in order to obtain a water soluble or dispersible hyperbranched polyamide, at least one of the multifunctional monomer unit reactants contains an amine, phosphine, arsenine or sulfide group, such that the highly branched polyamide contains in the backbone thereof an N, P, As or S atom capable of forming an onium ion.
There are, however, disadvantages associated with the polymerization processes described in the prior art for the manufacture of hyperbrancbed polyamides. First, the use of organic solvent is not environmentally friendly and practical. Second, as shown previously by Jikei and others (Macromolecules, 32, 2061 (1999)), the A
2
+B
3
polymerization of aromatic di-amine (A
2
) and aromatic tri-carboxylic acid (B
3
) can result in gelation within 10-20 min when the feed ratio of amino and carboxyl groups was equal to 1. Moreover, even with the feed ratio of 2:3 of amine to acid group in A
2
+B
3
approach of Jikei, the polymerization reaction employing solely aromatic monomers may only lead to soluble materials under certain conditions such as at very low concentration of monomer (<5g/L).
The conventional process for manufacturing commercial linear aliphatic polyamides is known as the “salt-strike” process. In this process, aliphatic dicarboxylic acid monomer is admixed with aliphatic diamine monomer in aqueous solution to form a salt. The salt is fed into a reactor in which both temperature and pressure are elevated. With the emission of water and volatile matter, molten polymer is formed and discharged. The following limitations may be associated with the described manufacture of linear polyamides: (a) the molar ratio of diamine and diacid must be equal to 1, or only low molecular weight material is obtained, (b) even with the ratio of diamine and diacid being 1, post-polymerization of pre-polymer at even higher temperature is often required in order to get high molecular weight material, (c) the resultant polymer chain usually only possesses limited NH
2
and/or COOH functionality (mostly not more than 2), and (d) high molecular weight linear polyamides are generally characterized by poor processability and solubility.
It would be desirable to provide a simple, practical, and environmentally friendly process for the manufacture of soluble hyperbranched polyamides with multifunctional groups. There is also another need to develop a manufacturing process which will work well with broader ranges of the ratio of amine groups to acidic groups. It would be further desirable to provide soluble highly branched polyamides obtained by condensation of multifunctional amine and multifunctional acid monomers where at least one of the multifunctional monomers is aliphatic, and where the ratio of total amine functional groups to total acid functional groups of the monomers is close to one.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the invention, a process for the manufacture of soluble hyperbranched polyamides is disclosed comprising
(a) combining in a reactor water and (a
1
) multi-functional di- or higher amine functional group containing monomers represented by the following formula (I) and multi-functional di- or higher carboxylic acid functional group containing monomers represented by the following formula (II), or a preformed salt of such di- or higher functional monomers, or (a
2
) multi-functional branching monomers of the formula (III):
R
1
(NH
2
)
x
(I)
R
2
(COOH)
y
(II)
A
n
—L—B
m
(III)
where in formulas (I) and (II), R
1
and R
2
are each independently a monomeric, oligomeric, or polymeric compound nucleus, x and y are integers of at least 2, preferably from 2 and 4, without x and y being 2 at the same time, and in formula (III), one of A and B represents an amine functional group, the other of A and B represents a carboxylic acid functional group, L represents a monomeric, oligomeric, or polymeric compound nucleus linking group between A and B, n is at
Anderson Andrew J.
Eastman Kodak Company
Hampton-Hightower P.
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