Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1999-06-01
2000-10-03
Hampton-Hightower, P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
528125, 528128, 528172, 528173, 528176, 528183, 528185, 528188, 528220, 528229, 528350, 528353, 525436, 525928, 4284111, 4284735, C08G 7310, C08G 6928, B32B 2700
Patent
active
061275093
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The current invention relates to polyimide polymers characterized by high glass transition temperatures, high thermal oxidative stabilities, and low moisture regain. The current invention also relates to the process of making these polyimides and their use in applications such as composites, films, laminates, and other products.
BACKGROUND OF THE INVENTION
Polymers comprised of polyimides have been found to have a variety of desirable qualities that are useful in high temperature applications. In general, and particularly for use as matrix materials in structural composites, the desirable qualities include a high glass transition temperature (Tg), high thermal oxidative stability (TOS), low moisture regain, and low conversion costs. While polyimide polymers exhibiting one or some of these qualities are known, there is a need for polyimide polymers that have all of these advantages.
Known composite systems having desirable characteristics include systems designated as Avimid.RTM. K and Avimid.RTM. N (E.I. du Pont de Nemours and Co.).
Avimid.RTM. K, described in A. R. Wedgewood, SAMPE Tech. Conf. 24, p. T385, 1992, employs a matrix based on pyromellitic dianhydride and extended ether diamines. These polymers are compatible with composite molding processes featuring melt consolidation of devolatilized prepreg plies. The glass transition temperature range of the polyimide component of Avimid.RTM. K is in the range of from 220 to 255.degree. C.
Avimid.RTM. N utilizes a polyimide polymer prepared from 2,2'-bis(3,4-dicarboxyphenyl)-hexafluoropropane tetracarboxylic acid (6FTA), the dianhydride form of which is referred to as 6FDA, along with a mix of p-phenylenediamine (PPD) and m-phenylenediamine (MPD). This polyimide polymer, designated and known in the art as NR-150, has a glass transition temperature range of about equal to or greater than 340.degree. C., with a reported moisture regain of about 3.7% by weight. See R. J. Boyce and T. P. Gannett, HIGH TEMPLE WORKSHOP XV, N, January 1995.
Another known polyimide polymer is comprised of biphenyl dianhydride and optionally pyromellitic dianhydride (PMDA) with 1,4-bis(4-aminophenoxy)-2-phenylbenzene (2PhAPB144) and MPD or PPD. See U.S. Pat. No. 5,478,913. This polymer exhibits a glass transition temperature range of about 220 to about 330.degree. C., with a moisture regain reported in R. J. Boyce and T. P. Gannett, HIGH TEMPLE WORKSHOP XV, N, January 1995, of about 2.8%.
The current invention provides novel polyimides which have relatively high Tg and with thermal oxidative stability and moisture regain characteristics significantly better than those exhibited by 6FTA or 6FDA based resins. The polyimide polymers of the current invention have good mechanical properties, making them useful in a wide variety of applications. Moreover, the invention has the potential of cost savings over the polyimides of the state of the art because the acid functional components of the current invention are relatively less expensive than the acid functional components of known polyimide polymers.
SUMMARY OF THE INVENTION
The current invention provides novel polyimide polymers having a high glass transition temperature (Tg), high thermal oxidative stability (TOS), and very low moisture regain, comprising the following recurring structural units: ##STR1## wherein the mole ratio of BTDA to BPDA in the polymer is from more than about 30 to less than about 70 (>30:<70) to about 80 to 20 (80:20), and Q is a suitable aromatic moiety. Also provided by the current invention are such polyimides formed from a precursor solution having a stoichiometric excess of either the diamine or dianhydride (or derivatives thereof) components as a means of controlling the molecular weight of the polyimide polymers formed. Moreover, the current invention also includes the use of end-capping agents. The end-capping agents may be non-reactive, reactive (if, for example, cross-linking is desired), or a mixture of both.
In addition to the resulting polyimides themselves, the
REFERENCES:
patent: 4512893 (1985-04-01), Makino et al.
patent: 4623563 (1986-11-01), Noda et al.
patent: 4720539 (1988-01-01), Rabilloud et al.
patent: 4731287 (1988-03-01), Noda et al.
patent: 4797307 (1989-01-01), Kunimoto et al.
patent: 4839217 (1989-06-01), Tabata et al.
patent: 5077382 (1991-12-01), Meterko et al.
patent: 5138028 (1992-08-01), Paul et al.
patent: 5177180 (1993-01-01), Griffin et al.
patent: 5243024 (1993-09-01), Bockrath et al.
patent: 5264545 (1993-11-01), Blum et al.
patent: 5300620 (1994-04-01), Okikawa et al.
patent: 5304626 (1994-04-01), Burgers et al.
patent: 5411765 (1995-05-01), Kanakarajan et al.
patent: 5412066 (1995-05-01), Hergenrother et al.
patent: 5464927 (1995-11-01), Angelopoulos et al.
patent: 5478913 (1995-12-01), Boyce et al.
patent: 5493002 (1996-02-01), McGrath et al.
patent: 5830564 (1998-11-01), Kohno et al.
PCT International Search Report, dated May 7, 1998.
R.J. Boyce & T.P. Gannett, "AVIMID.RTM.R A New High Temperature Polyimide Matrix Composite", High Temple Workshop XV, N, Jan. 1995.
Bessonov et al., "Polyimides: Thermally Stable Polymers", trans. ed. W.W. Wright, pp. 103-108 (Consultants Bureau), N.Y., N.Y. 1987.
Pratte James F.
Tanikella Murty S.
E. I. Du Pont de Nemours and Company
Fiberite Inc.
Hampton-Hightower P.
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