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
2003-04-22
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
C528S198000
Reexamination Certificate
active
06552158
ABSTRACT:
BACKGROUND
The disclosure relates to articles fabricated from polycarbonates and methods of making these articles using the polycarbonates.
Polycarbonates 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. Polycarbonates have been used extensively for optical media applications such as for data storage and retrieval. Bisphenol A (BPA) polycarbonate, 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 disks and digital versatile disks (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 or DVD+R), and DVD-rewritable (DVD−RW or 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.
One of the properties that influences 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 can result in skewing of the disk or the film, 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 comprised of a polymer material, the flatness of the disk depends on the low water absorption of the polymeric material. Similarly, a film produced from BPA polycarbonate can exhibit warpage 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 disks through, for example, 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 requirements of dimensional stability, in addition to replication and cycle time, without compromising on any of the other desirable characteristics that BPA homopolycarbonate already possesses.
Polycarbonates having high glass transition temperatures and enhanced resistance to thermal degradation are highly sought after materials by industries, particularly those serving the automotive, aircraft, and display devices markets. In the automotive industry, they may be used, for example, in the production of headlamp lenses, such as those for headlamps and fog lamps, which are becoming smaller in size and characterized by closer proximity of the lenses to the heat-generating source. Other automotive lighting applications of such polycarbonates include articles such as bezels used for headlamps and fog lamps. Another application of such polycarbonates is for producing transparent, high temperature-stable films that can, for example be utilized in display devices.
Polycarbonates can be manufactured by direct reaction of an aromatic dihydroxy compound, such as BPA with phosgene using the so-called interfacial method, or the transesterification method, also sometimes referred to as the melt method, which involves an ester exchange reaction between the aromatic dihydroxy compound and a carbonic acid diester, such as diphenyl carbonate. The melt process gives a polycarbonate which generally contains very low levels of inorganic impurities and particulates, and which exhibits outstanding stability under polymer processing conditions.
Japanese Kokai Patent Application 7-003002 discloses manufacture of polycarbonates from cyclic terpene containing polyhydric phenols of undisclosed structures. Japanese Kokai Patent Application 8-198791 discloses polycarbonates obtained by polymerization of 1,3- and 2,8-bis(hydroxyaryl)cyclohexane derivatives. However, the average weight molecular weights of the polycarbonates were below 10,000, and the glass transition temperatures reported were also relatively low making these polycarbonates inferior candidates for fabricating articles for applications, optical media applications and display devices.
BRIEF SUMMARY
Briefly, one embodiment of the disclosure is an optical disk comprising a polycarbonate layer, wherein the polycarbonate is produced using a bis(hydroxyaryl)cyclohexane selected from the group consisting of the formula:
wherein each A
1
is independently a divalent substituted or unsubstituted radical; and at least one aromatic dihydroxy compound comonomer of the formula:
HO—A
2
—OH,
wherein A
2
is selected from divalent substituted or unsubstituted aromatic radicals and, wherein the polycarbonate produced comprises a weight average molecular weight of at least about 10,000, a glass transition temperature of at least about 100° C., and a percentage elongation of less than about 0.025% relative to its initial length following exposure to nitrogen with a relative humidity of about 100%, at a temperature of about 23° C., and for a duration of about 3 hours.
Another embodiment is an article comprising a polycarbonate produced by using bisphenol composition comprising at least one bis(hydroxyaryl)cyclohexane selected from the group consisting of:
at least one aromatic dihydroxy compound comonomer having the formula:
HO—A
2
—OH,
wherein A
2
is selected from divalent substituted or unsubstituted aromatic radicals.
In another embodiment, an optical disk comprises a polycarbonate layer produced using a catalyst composition and a monomer composition, wherein the monomer composition comprises a diphenyl carbonate; a bisphenol composition, and an aromatic dihydroxy comonomer compound, wherein the aromatic dihydroxy compound comprises resorcinol, bisphenol A, 4,4′-(1-decylidene)-bisphenol, 2,2-bis (3-sec-butyl-4-hydroxyphenyl)propane, and combinations comprising at least of the foregoing aromatic dihydroxy comonomer compounds, and wherein the bisphenol composition comprises at least one bis(hydroxyaryl)cyclohexane selected from the group consisting of:
wherein each A
1
is independently a substituted or unsubstituted divalent aromatic radical.
A display device comprising a polycarbonate protective layer, wherein the polycarbonate is produced using a bis(hydroxyaryl)cyclohexane selected from the group consisting of the formula:
wherein each A
1
is independently a divalent substituted or unsubstituted radical; and at least one aromatic dihydroxy compound comonomer of the formula:
HO—A
2
—OH,
wherein A
2
is selected from divalent substituted or unsubstituted aromatic radicals and, wherein the polycarbonate produced comprises a weight average molecular weight of at least about 10,000, a glass transition temperature of at least about 100° C., and a percentage elongation of less than about 0.025% relative to its initial length following exposure to nitrogen with a relative humidity of about 100%, at a temperature of about 23° C., and for a duration of about 3 hours.
The disclosure further relates to methods for making such articles from the above polycarbonates. The embodiments of the present disclosure have many advantages, including the a
Chatterjee Gautam
Dhara Dibakar
Faber Rein Mollerus
Lens Jan Pleun
Srinivasan Veeraraghavan
Boykin Terressa M.
General Electric Company
LandOfFree
Dimensionally stable polycarbonate articles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dimensionally stable polycarbonate articles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dimensionally stable polycarbonate articles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3106357