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
2002-01-07
2004-05-11
Hightower, P. Hampton (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...
C525S420000, C525S422000, C525S432000, C525S434000, C525S436000, C252S500000, C252S502000, C252S510000, C252S511000, C524S439000, C524S440000, C524S495000, C264S614000, C264S641000, C106S472000
Reexamination Certificate
active
06734262
ABSTRACT:
BACKGROUND OF INVENTION
This Invention relates to methods for forming conductive thermoplastic polyetherimide polyester compositions and the articles formed thereby. Thermoplastic compositions comprising blends of polyetherimide resins and polyester resins are materials possessing thermal and dimensional stability particularly because the high flow temperatures of both materials permit them to be used in high temperature environments. The high flow temperatures however, cause manufacturing or assembly of articles made from these compositions to be cumbersome, expensive and time consuming because of the necessity of heating these materials to high temperatures and subsequently cooling them back to room temperature. It is therefore desirable to create thermoplastic compositions that in addition to being thermally and dimensionally stable are electrically conductive and can be rapidly heated to temperatures above the softening point of the compositions so that they can easily be assembled.
SUMMARY OF INVENTION
An electrically conductive thermoplastic composition with a superior ability to be heated rapidly in an electromagnetic field comprises a polyetherimide resin, a polyester resin, and electrically conductive filler. Such compositions display good dimensional stability at elevated temperatures, especially when heated rapidly using electromagnetic radiation, which renders them useful in articles and operations where rapid assembly is important.
DETAILED DESCRIPTION
It has been discovered that by blending thermoplastic resins such as polyetherimides, with polyester resins and an electrically conductive filler, it is possible to obtain moldable thermoplastic articles which possess unique properties such as low shrinkage, low coefficient of thermal expansion, electrical conductivity, increased elastic modulus and high impact-strength. In addition such compositions have good thermal and dimensional stability and can be heated efficiently and uniformly using electromagnetic energy such as microwave or radio frequency radiation. Uniform heating in the presence of an electromagnetic field is very useful in applications that require fast assembly, for example in inkjet pen cartridges and other items where different plastic parts are quickly heated in order to fuse them together during assembly.
Preferred polyetherimide resins comprise more than 1, typically about 10 to about 1000 or more, and more preferably about 10 to about 500 structural units, of the formula (I)
wherein T is —O— or a group of the formula —O—Z—O— wherein the divalent bonds of the —O— or the —O—Z—O— group are in the 3,3′, 3,4′, 4,3′, or the 4,4′ positions, and wherein T includes, but is not limited, to divalent radicals of formula (II) as defined below
where Q in the above formula (II) may be divalent moiety selected from the group consisting of —O—, —S—, —C(O)—, —SO2—, —SO—, —CyH2y— (y being an integer from 1 to 5), and halogenated derivatives thereof, including perfluoroalkylene groups, or a group of the formula —O—Z—O— wherein the divalent bonds of the —O— or the —O—Z—O— group are in the 3,3′, 3,4′, 4,3′, or the 4,4, positions, and wherein Z Includes, but is not limited, to divalent radicals of formula (II) above. R in formula (I) includes but is not limited to substituted or unsubstituted divalent organic radicals such as: (a) aromatic hydrocarbon radicals having about 6 to about 20 carbon atoms and halogenated derivatives thereof; (b) straight or branched chain alkylene radicals having about 2 to about 20 carbon atoms; (c) cycloalkylene radicals having about 3 to about 20 carbon atoms, or (d) divalent radicals of the general formula (III)
wherein Q is defined in formula (II) above.
In one embodiment, the polyetherimide may be a copolymer, which, in addition to the etherimide units described above, further contains polyimide structural units of the formula (IV)
wherein R is similar to that in formula (I) and includes but is not limited to substituted or unsubstituted divalent organic radicals such as, (a) aromatic hydrocarbon radicals having about 6 to about 20 carbon atoms and halogenated derivatives thereof; (b) straight or branched chain alkylene radicals having about 2 to about 20 carbon atoms; (c) cycloalkylene radicals having about 3 to about 20 carbon atoms, or (d) divalent radicals of the general formula (V)
wherein Q includes but is not limited to a divalent moiety selected from the group consisting of —O—, —S—, —C(O)—, —SO
2
—, —SO—, —C
y
H
2y
—(y being an integer from 1 to 5), and halogenated derivatives thereof, including perflfluoroalkylene groups. M includes, but is not limited to, radicals of formula (VI)
wherein W is a divalent moiety selected from the group consisting of —O—, —S—, —C(O)—, —SO
2
—, —SO—, —C
y
H
2y
— (y being an integer from 1 to 5), and halogenated derivatives thereof, including perflfluoroalkylene groups, or a group of the formula —O—Z—O— wherein the divalent bonds of the —O— or the —O—Z—O— group are in the 3,3′, 3,4′, 4,3′, or the 4,4′ positions, and wherein Z includes, but is not limited, to divalent radicals of formula (II). Suitable substituents may be alkyl ethers, esters or amides, or aryl ethers, esters or amides, epoxides, alkyl groups or aryl groups, and the like.
The polyetherimide can be prepared by any of the methods well known to those skilled in the art, including the reaction of an aromatic bis(ether anhydride) of the formula (VII)
with an organic diamine of the formula (VIII)
H2N—R—NH2 (VIII)
wherein T and R are defined as described above in formula (I).
Examples of specific aromatic bis(ether anhydride)s and organic diamines are disclosed, for example, in U.S. Pat. Nos. 3,972,902 and 4,455,410, which are incorporated herein by reference. Illustrative examples of aromatic bis(ether anhydride)s of formula (VII) include: 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4′-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride; 4,4′-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride; 4,4′-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride; 4,4′-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride; 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4′-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride; 4,4′-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride; 4,4′-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride; 4,4′-bis(2,3-dicarboxyphenoxy)diphenyl sulfone dianhydride; 4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenyl-2,2-propane dianhydride; 4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenyl ether dianhydride; 4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride: 4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)benzophenone dianhydride and 4-(2,3-dicarboxyphenoxy)-4′-(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride, as well as various mixtures thereof.
The bis(ether anhydride)s can be prepared by the hydrolysis, followed by dehydration, of the reaction product of a nitro substituted phenyl dinitrile with a metal salt of dihydric phenol compound in the presence of a dipolar, aprotic solvent. A preferred class of aromatic bis(ether anhydride)s included by formula (VII) above includes, but is not limited to, compounds wherein T is of the formula (IX)
and the ether linkages, for example, are preferably in the 3,3′, 3,4′, 4,3′, or 4,4′ positions, and mixtures thereof, and where Q is as defined above.
Any diamino compound may be employed as long as it does not interfere with the synthesis or use of the product. Examples of suitable compounds are ethylenediamine, propylenediamine, trimethylenediamine, diethylenetriamine, triethylenetertramine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, 1,12-dodecanediamine, 1,18-octadecanediamine, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 4-methylnonamethylenediamine, 5
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