POLYETHERIMIDESILOXANE COPOLYMER COMPOSITIONS CONTAINING HIGH MELT FLOW POLYETHERIMIDE HOMOPOLYMER

Abstract: Polyetherimide siloxane copolymer compositions are provided which contain amounts of a high melt flow polyetherimide homopolymer. The compositions exhibit enhanced levels of impact strength and tensile elongation. The compositions are useful for making molded articles.

Description: POLYETHERIMIDESILOXANE C0P0LYMER COMPOSITIONS CONTAINING HIGH MELT FLOW POLYETHERIMIDE HOMOPOLYMER BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to polyetherimide homopolymer siloxane polyetherimide copolymer blends, and more particularly relates to siloxane polyetherimide compositions containing a small amount of high melt flow polyetherimide homopolymer. Description of Related Art Flame resistant polyetherimide homopolymer/- siloxane polyetherimide copolymer blends are set forth in EP 307670 corresponding to Male, et. al., U.S. patent application 092,940 filed September 4, 1987; and EP 266595 corresponding to U.S. patent application 925,916 filed November 3, 1986. Male, et. al., U.S. patent application 092,940, discloses blends comprising (i) a polyetherimide (ii) a siloxane polyetherimide copolymer and a perfluorocarbon, and discloses that the siloxane polyetherimide copolymer is employed in an impact strength enhancing concentration; for example, from about 2% to about 90% by weight of the blend, and that the perfluorocarbon polymer is employed in a flammability-retarding amount, typically from about 0.2% by weight to 20% by weight of the polymer blend. EP 266915 published May 11, 1988 and U.S. patent application 925,916 filed November 3, 1986, disclose blends comprising (i) a polyetherimide and (ϋ) a siloxane polyetherimide copolymer in an impact strength enhancing concentration, for example from about 2% to about 90% by weight of the blend. While the foregoing discloses improving the impact strength of polyetherimide compositions, there is a need to improve the impact strength and tensile elongation of siloxane-polyetherimide copolymer compositions. Accordingly, one object of the present invention is to provide siloxane-polyetherimide compositions exhibiting improved levels of impact strength and tensile elongation. SUMMARY OF THE INVENTION The present invention involves polyetherimide- siloxane copolymer compositions containing small amounts of high melt flow polyetherimide homopolymer to improve the impact strength and tensile elongation of the composition. The composition is useful as a molding resin for making molded articles, wire coatings and extruded parts. DETAILED DESCRIPTION OF THE INVENTION Preferably the polyetherimide resin has a relatively high melt flow which is preferably at least 15 g/10 min., more preferably between 15 and 80 g/10 min., and most preferably between 20 and 60 g/10 min. as measured by ASTM D1238 modified by using a weight of 6700 grams at a temperature of 650°F. The high melt flow polyetherimide resin appears to improve the notched Izod impact and tensile elongation values of the blends. The siloxane polyetherimide copolymers employed in the blends of this invention may be prepared in a manner similar to that used for polyetherimides, except that a portion or all of the organic diamine reactant is replaced by an amine-ter inated organosiloxane of the formula: (I) H 2 N - (CH 2 ) n _ Si _ (0-Si) g _ (CH 2 ) m _ NH 2 CH 3 CH 3 wherein n and m independently are integers from 1 to about 10, preferably from 1 to about 5, most preferably about 3, and g is an integer from 1 to about 40, preferably from about 5 to about 25, and most preferably from 8 to 12. The siloxane polyetherimide copolymers employed in the compositions of the present invention are referred to as late addition siloxane polyetherimide copolymers which are made by first reacting the organic diamine of formula XII with excess bis(ether anhydride) and to form anhydride terminated oligo ers and then reacting the amine-terminated organosiloxane of formula I. The diamine component of the siloxane polyetherimide copolymers generally contains from about 20 to 50 mole % of the amine-terminated organosiloxane of formula I and from about 50 to 80 mole % of the organic diamine of formula XII. In preferred copolymers, the diamine component contains from about 25 to about 40 mole %, most preferably about 35 to 40 mole % of the amine-terminated organosiloxane. The polyetherimides used for preparing the blends of this invention contain repeating groups of the formula: (II) wherein "a" is an integer greater than 1, e.g., from 10 to 10,000 or more; T is — 0 — or a group of the formula: (III) _ 0 — Z — 0 — wherein the divalent bonds of the — 0 — or the — 0 — Z — 0 — group are in the 3,3'; 3,4'; 4,3', or the 4,4' positions; Z is a member of the class consisting of (A): (IV) and (B) divalent organic radicals of the general formula: (V) where X is a member selected from the group consisting of divalent radicals of the formulas: (VI) 0 0 where y is an integer from 1 to about 5; and R is a divalent organic radical selected from the group consisting of (a) aromatic hydrocarbon radicals having from 6 to about 20 carbon atoms and halogenated derivatives thereof, (b) alkylene radicals having from 2 to about 20 carbon atoms, cycloalkylene radicals having from 3 to about 20 carbon atoms, and (c) divalent radicals of the general formula: (VII) ' - Q -^0> where is a member selected from the group consisting of: (VIII) 0 0 ιl li -S— . —0- -C— —S— and -Cx Y H π 2x ~ 0 and x is an integer from 1 to about 5. In one embodiment, the polyetherimide may be a copolymer which, in addition to the etheri ide units described above, further contains polyimide repeating units of the formula: (IX) wherein R is as previously defined and M is selected from the group consisting of: (X) where B is —S — or — — . These polyetherimide copolymers and their preparation are described by Williams, et. al . in U.S. Patent No. 3,983,093, incorporated herein by reference. The polyetherimides can be prepared by any of the methods well known to those skilled in the art, including the reaction of the aromatic bis(ether anhydride) of the formula: (XI) with an organic diamine of the formula: (XII) H 2 N — R — NH 2 wherein T and R are defined as described above. Bis(ether anhydride)s of formula XI include, for example, 1,3-bis(2,3-dicarboxyphenoxy)benzene dianhydride; 1,4-bis(2,3-dicarboxyphenoxy)benzene dianhydride; 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride; and 1,4-bis(3,4-d carboxyphenoxy)benzene dianhydride; 4,4'-bis(phthalic anhydride)ether. A preferred class of aromatic bis (ether anhydride)s included by formula XI includes compounds of formula XIII, XIV, and XV, which follow: (xiv) (XV) and mixtures thereof, where Y is selected from the group consisting of — 0 —, — S —, — C — and — S CH- Aromatic bis(ether anhydride)s of formula XIII include, for example: 2,2-bis(4-(3,4-dicarboxyphenoxy)phenyl)propane dianhydride (BPADA); 4,4'-bis(3,4-dicarboxyphenoxy)dipheny1 ether dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)dipheny1 sulfide dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride; and mixtures thereof. Aromatic bis(ether anhydride)s of formul a XIV i ncl ude, for example: 2,2-bis(4-(2,3-dicarboxyphenoxy)phenyl)propane di nhydride; 4,4'-bis(2,3-dicarboxyphenoxy)dipheny1 ether dianhydr de; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride; 4,4'-bis( ,3-dicarboxyphenoxy)dipheny1 sulfone d anhydride; and mixtures thereof. The aromatic bis(ether anhydride)s of formula XV may be, for example, 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxy¬ phenoxy) diphenyl-2,2-propane dianhydride; 4-(2,3-dicarboxyphenoxy-4'-(3,4-dicarboxy- phenoxy)diphenyl ether dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxy¬ phenoxy) diphenyl sulfide dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxy- phenoxy)benzophenone dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxy- phenoxy)diphenyl sulfone dianhydride, and mixtures thereof. When polyetherimide/polyimide copolymers are employed, a dianhydride, such as pyromellitic anhydride, is used in combination with the bis(ether anhydride). Some of the aromatic bis(ether anhydride)s of formula XI are shown in U.S. Patent No. 3,972,902 (Darrell Heath and Joseph Wirth). As described therein, the bis(ether anhydride)s can be prepared by the hydrolysis, followed by dehydration, of the reaction product of a nitrosubstituted pheny! dinitrile with a metal salt of dihydric phenol compound in the presence of a dipolar, aprotic solvent. Additional aromatic bis(ether anhydride)s also included by formula XI above are shown by Koton, M.M., Florinski, F.S., Bessonov, M.I. and Rudakov, A.P. (Institute of Heteroorganic Compounds, Academy of Sciences, U.S.S.R.), U.S.S.R. patent 257,010, November 11, 1969, Appl . May 3, 1967, and by M.M. Koton, F.S. Florinski, Zh. Orα. Khin. 4(5), 774 (1968). The organic diamines of formula XII include, for example: m-phenylenediamine (MPD), p-phenylenediamine, 4,4'-diaminodipheny1propane, 4,4'-diaminodiphenylmethane (commonly named 4,4'-methylenedianiline), 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether (commonly named ,4'-oxydianiline), 1,5-diaminonaphthalene, 3,3-diamethylbenzidine, 3,3-dimethoxybenzidine, 2,4-bis(beta-amino-t-butyl)toluene, bis(p-beta-amino-t-butylphenyl)ether, bis(p-beta-methyl-o-aminophenyl)benzene, 1,3-diamino-4-isopropylbenzene , 1,2-bis(3-aminopropoxy)ethane, benzidine, m-xylylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, bis(4-aminocyclohexyl)methane, 3-methylhepta ethylenediamine, 4,4-d methylheptamethylenediamine, 2,11-dodecanediamine, 2,2-dimethylpropylenediamine, octamethylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylhexa ethylenediamine, 2,5-di ethyl eptamethylenediamine, 3-methy1heptamethylenediamine, 5-methylnonamethylenediamine, 1,4-cyclohexanediamine, 1,12-octadecanediamine, bis(3-aminopropyl)sulfide, N-methyl-bis(3-aminopropyl )amine, hexamethylenediamine, heptamethylenediamine, nonamethylenediamine, decamethylenediamine, and mixtures of such diamines. Both the polyetherimides and the siloxane polyetherimide copolymers used in the blends of this invention may be prepared by any of the procedures conventionally used for preparing polyetherimides. A presently preferred method of preparation is described in U.S. Patent No. 4,417,044, which is incorporated herein by reference. Blending the polyetherimide resin with the polyetherimide-siloxane copolymer in the amounts of the present invention provides a blend which is primarily polyetherimide-siloxane copolymer but which exhibits certain improved properties over either the polyether-siloxane copolymer or polyetherimide resin alone. In addition to the polymeric ingredients, the blends may contain other materials, such as fillers. additives, reinforcing agents, pigments and the like. These blends exhibit very low flammabilities. The polyetherimide resin is employed in the present blends in small amounts which enhance the impact strength and tensile elongation of the composition. Such concentration of the polyetherimide homopolymer can range from 1% to 10% by weight based on the total weight of the composition, more preferably from 2.5% to 7.5% by weight thereof, and most preferably from 5% to 7.5% by weight thereof; preferably the polyetherimide-siloxane copolymer is present at a level of from 99.0% to 90% by weight of the composition, more preferably from 97.5% to 92.5% by weight thereof, and most preferably from 92.5% to 95% by weight of the composition. The following examples illustrate the present invention and are not meant to be limiting. EXAMPLES The following examples illustrate the present invention but are not meant to limit the scope thereof. Examples A, B, C, D and E are comparative examples. Example A is 100% by weight of a polyetherimidesiloxane copolymer, and Example B is 100% by weight of a polyetherimide. Examples 1, 2, 3, 4, 5 and 6 illustrate the enhanced properties obtained by blending a small amount of a relatively high melt flow polyetherimide with a relatively large amount of a late addition polyetherimide- siloxane. The following abbreviations were used in Table 1: LA PEI/Si is a late addition polyetherimide¬ siloxane copolymer made by reacting BPADA, MPD, and an amine terminated organosiloxane of formula (I) wherein g=9 r n=3 and m=3. The amine terminated organosiloxane (ATO) was present at a level of about 40 mole percent based on the total moles of amine terminated organosiloxane and organic diamine. The moles of BPADA employed was substantially equal to the combined moles of MPD and ATO. PEI for examples for 1 to 4 is a polyetherimide made by reacting BPADA, MPD and having a melt flow value of 20 g/10 min. TS = Tensile strength in pounds per square inch as determined according to ASTM D638. TE = Tensile elongation in % as determined according to ASTM D638. FM = Flexural modulus in Mpsi as determined according to ASTM D790. NI = Notched Izod in ft-lb/in as determined according to ASTM D256. MI = Melt index in g/10 min as determined according to ASTM D1238 modified by using a weight of 6700 grams at a temperature of 343.3°C (650°F). TABLE 1 LA PEI/Si PEI TS TE FM FS NI The above LA PEI/Si is a late addition polyetherimide siloxane made by first reacting excess BPA dianhydride with meta phenylene diamine to form anhydride terminated oligo ers and then reacting silicone diamine (wherein g is 9) therewith to form late addition polyetherimidesiloxanes. The PEI is the reaction product of BPA dianhydride and metaphenylene diamine having an MI of 20 g/10 min. Note example -3 provides the highest tensile elongation and notched Izod values. The values set forth for example B (Melt Flow between 16 to 20 g/10 min) are not the actual values but are the typical values for the type of PEI employed in examples 1 to 4. TABLE 2 LA PEI/Si (wt %) PEI (wt %) PEI MI (g/10 min) TS (psi) TE (%) FM (kpsi) FS (psi) HOT ( * C) NI (ft lb/in) The PEI/Si was the late addition polyetherimide siloxane of Table 1. The PEI's of examples C, 5 and 6 had different melt flow values. The PEI's of C, 5 and 6 are made by reacting MPD with BPADA. TABLE 3 D QBPEI/Si (wt %) PEI (wt %) PEI MI TS (psi) TE (%) FM (kpsi) FS (psi) HDT ( # C) NI (ft lb/in) The QB polyetherimide siloxane of Examples D and E is made by (i) reacting the siloxane diamine (g=9, n=3, m=3) with substantially equal moles of BPA dianhydride and (ii) reacting the metaphenylene diamine with substantially equal moles of BPA dianhydride and then reacting the products of (i) with the products of (ii) to form the QB PEI/Si. The PEI of E and B is the reaction product of BPADA and MPD.

Claims: What is claimed: 1. A thermoplastic composition comprising: (a) a polyetherimide-siloxane copolymer wherein said polyetherimide-siloxane copolymer is prepared by: (i) reacting an aromatic diamine with excess bis(etheranhydride) to form anhydride terminated oligomers; and (ii) reacting the anhydride terminated oligomers with a siloxane diamine; and (b) a tensile elongation improving amount of a high melt flow polyetherimide homopolymer present at a level of from 1% to 10% by weight based on the total weight of the composition. 2. The composition of claim 1 wherein said polyetherimide resin is present at a level of from 2.5% to 7.5% by weight based on the total weight of the composition. 3. The composition of claim 2 wherein said polyetherimide resin has a melt flow value of at least 15 g/10 min. as measured by ASTM D1238 modified by using a weight of 6700 grams at a temperature of 650 C F. 4. The composition of claim 3 wherein said polyetherimide-siloxane copolymer is present at a level of from 92.5% to 97.5% by weight based on the total weight of the composition. 5. The composition of claim 4 wherein said polyetherimide homopolymer consists of repeating units of the formula: where T is -0- or a group of the formula -O-Z-O- wherein the divalent bonds of the -0- or the -O-Z-O- group are in the 3,3', 3,4', 4,3' or 4,4' positions; Z is a member of the class consisting of (A) CH. , and and (B) divalent organic radicals of the general formula: where X is a member selected from the group consisting of divalent radicals of the formulas: - C y H 2y— __C- —S— , —0— and —S— where y is an integer from 1 to about 5; and R 10 is a divalent organic radical selected from the group consisting of (a) aromatic hydrocarbon radicals having from 6 to about 20 carbon atoms and halogenated derivatives thereof, (b) alkylene radicals having from 2 to about 20 15 carbon atoms, cycloalkylene radicals having from 3 to about 20 carbon atoms, and (c) divalent radicals of the general formula: ^δ^ Q -<δ - where Q is a member selected from the group consisting of: .0— , _C— , —S— and -C χ H 2χ _ and x is an integer from 1 to about 5. The composition of claim 5 wherein said polyetherimide-siloxane copolymer has repeating units of the formula: The composition of claim 6 wherein said polyetherimide resin has a melt flow of between 20 and 60 g/10 min. as measured by ASTM D1238 modified by using a weight of 6700 grams at a temperature of 650 β F.

Inventors: DURFEE NORMAN EUGENE JR, ROCK JOHN ANDREW, DURFEE, NORMAN, EUGENE, JR., ROCK, JOHN, ANDREW
Applicants: GEN ELECTRIC, GENERAL ELECTRIC COMPANY
Application year: 1991
Main classification: C08G73
IPC codes: C08G73, C08G77, C08L79, C08L83