Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2002-07-03
2004-02-10
Boykin, Terressa M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S196000, C528S271000, C528S272000
Reexamination Certificate
active
06689862
ABSTRACT:
BACKGROUND
The disclosure relates to polyestercarbonates and more particularly, to polyestercarbonates based on bisphenols derived from cyclic monoterpene precursors as one of the building blocks. The disclosure also relates to melt transesterification polymerization methods for making the polyestercarbonates and to methods for making such articles from the polyestercarbonates.
Polycarbonate homopolymers are widely used in a variety of applications by virtue of their excellent physical properties, such as impact resistance, mechanical characteristics, transparency, and the like. Bisphenol A (BPA) polycarbonate, the industry benchmark material, by virtue of its low cost, good transparency, and mechanical properties has served as the substrate of choice for optical data storage media such as compact disk and digital versatile disk (DVD). However, the need to store greater amounts of information on individual disks has resulted in newer techniques for high-density data storage, based on multiple information layers and shorter wavelength lasers, such as high density DVD (HDDVD), digital video recordable (DVR), DVD-recordable (DVD−R and DVD+R), and DVD-rewritable (DVD−RW and DVD+RW) formats. The transparent plastic layer that forms the non-interfering shielding on such optical media disks requires more demanding material specifications, such as high transparency, heat resistance, low water absorption, ductility and fewer particulates that standard BPA homopolycarbonate cannot meet. Therefore, polyestercarbonates have been studied for their utility as a more effective material for optical media applications, such as data storage and retrieval.
One of the critical properties that influence the efficacy of a given material for higher data storage density is the spacing between the pits and grooves on the substrate material. Since data is stored in these pits and grooves, the flatness of the disk is necessary to prevent loss of information. It is known that excessive moisture absorption by the disk results in skewing of the disk or the films that form the disk, which in turn leads to reduced reliability. This skewing, hereinafter referred to as dimensional stability, will result in data being stored or read inaccurately by the laser beam. Since the bulk of the disk is generally comprised of polymer material, the flatness of the disk depends on the low water absorption of the polymeric material. For example, a film produced from conventional BPA polycarbonate often exhibits warp due to absorption of ambient moisture. The dimensional stability is a function of, among other factors, the amount of ambient moisture present as well as the rate of moisture absorption. In addition to possessing optimum dimensional stability, a satisfactory material for such advanced format optical disks should also exhibit optimum replication and cycle time vis-à-vis the conditions for manufacturing conventional optical disks, such as compact disks. In order to produce high quality disks through injection molding, the polymer should also be easily processible, that is, exhibit good flow. Therefore there is a continued need for developing new materials as suitable substrates that would serve these advanced data storage formats. Suitable materials for high-density storage formats should satisfactorily address the critical requirement of dimensional stability, in addition to replication and cycle time, without compromising on any of the other desirable characteristics that BPA homopolycarbonate already possesses.
BRIEF SUMMARY
A polyestercarbonate comprising structural units derived from at least one bisphenol of the formulas:
wherein each A
1
is independently a divalent substituted or unsubstituted aromatic radical; at least one aromatic dihydroxy compound of the formula:
HO—A
2
—OH
wherein A
2
is selected from divalent substituted and unsubstituted aromatic radicals; at least one dicarboxylic acid diester of the formula:
wherein Y is a C
1
-C
40
linear or branched divalent hydrocarbyl radical, and R′ is a C
7
-C
12
aryl or alkaryl radical; and at least one carbonic acid diester of the formula (ZO)
2
C═O, wherein each Z is independently an unsubstituted or substituted alkyl radical, or an unsubstituted or substituted aryl radical.
In another embodiment, the polyestercarbonate comprises structural units derived from at least one bisphenol of the formulas:
at least one aromatic dihydroxy compound comonomer selected from the group consisting of resorcinol, bisphenol A, 4,4′-(1-decylidene)-bisphenol, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane and mixtures thereof; at least one dicarboxylic acid diester of the formula
wherein Y is a linear divalent hydrocarbyl group of the formula (CH
2
)
n
, wherein n has values in the range from about 4 to about 18, and R′ is phenyl; and diphenyl carbonate, wherein the polyestercarbonate has a glass transition temperature of at least about 100° C.; a weight average molecular weight of at least about 5,000; and a dimensional stability as measured by percentage elongation of less than about 0.05% relative to its initial length following exposure to air with a relative humidity of about 100%, at a temperature of about 23° C., and for a duration of about 3 hours.
A melt transesterification polymerization method for producing a polyestercarbonate is disclosed herein. The method comprises combining a catalyst and a reactant composition to form a reaction mixture; and mixing the reaction mixture under reactive conditions for a time period to produce a polyestercarbonate product, wherein the reactant composition comprises a carbonic acid diester of the formula (ZO)
2
C═O, where each Z is independently an unsubstituted or substituted alkyl radical, or an unsubstituted or substituted aryl radical; at least one bisphenol of the formula:
wherein each A
1
is independently a substituted or unsubstituted divalent aromatic radical; at least one aromatic dihydroxy compound comonomer selected from the group consisting of
HO—A
2
—OH
wherein A
2
is selected from divalent substituted or unsubstituted aromatic radicals; and at least one dicarboxylic acid diester selected from the group consisting of
wherein Y is a C
1
-C
40
linear or branched divalent hydrocarbyl radical, and R′ is a C
7
-C
12
aryl or alkaryl radical.
In another embodiment, the method for producing a polyestercarbonate by a melt transesterification polymerization method comprises combining a catalyst comprising at least one of sodium hydroxide or tetramethylammonium hydroxide, and a reactant composition to form a,reaction mixture; and mixing the reaction mixture under reactive conditions for a time period to produce a polyestercarbonate product, wherein the reactant composition comprises a diphenyl carbonate; at least one bisphenol of the formulas:
at least one aromatic dihydroxy compound comonomer selected from the group consisting of resorcinol, bisphenol A, 4,4′-(1-decylidene)-bisphenol, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane and mixtures thereof; and at least one dicarboxylic acid diester selected from the group consisting of
wherein Y is a linear divalent hydrocarbyl group of the formula (CH
2
)
n
, wherein n has values in the range from about 4 to about 18, and R′ is phenyl.
The embodiments of the present disclosure have many advantages, including the ability to manufacture the above mentioned polyestercarbonates in a cost effective, environmentally acceptable manner, and for fabricating articles and films suitable for high heat, and optical data storage/retrieval applications.
DETAILED DESCRIPTION
Disclosed herein are polyestercarbonates that are suitable for high density storage formats. The polyestercarbonates are preferably formed by melt transesterification (i.e., a melt method) of bisphenol compound, an aromatic dihydroxy compound comonomer, a dicarboxylic acid compound, and a carbonic acid diester compound.
Preferably, the bisphenol compounds are derived from cyclic monoterpene precursors, and more preferably comprise those having for
Faber Rein Mollerus
Lens Jan Pleun
Srinivasan Veeraraghavan
Boykin Terressa M.
General Electric Company
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