Substantially single phase silicone copolycarbonates,...

Details Substantially single phase silicone copolycarbonates,... Substantially single phase silicone copolycarbonates,...

2000-07-10

2002-12-10

Buttner, David J. (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From silicon reactant having at least one...

C528S025000, C528S204000, C525S464000

Reexamination Certificate

active

06492481

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to substantially single phase silicone copolycarbonates suitable for use in optical articles, methods for making such silicone copolycarbonates and methods for controlling the physical properties of silicone copolycarbonates. Material properties of silicone copolycarbonates are found to be controlled both by composition and method of preparation. Control of product properties by method of preparation is provided by two methods which provide identically constituted materials having different physical properties. This invention further relates to optical articles, and methods for making optical articles from the silicone copolycarbonates.
BACKGROUND OF THE INVENTION
The past two decades have seen tremendous growth in the use of optical plastics in information storage and retrieval technology. Polycarbonates and other polymer materials are utilized widely in optical data storage media, such as compact disks. In optical data storage applications, it is desirable that the plastic material chosen have excellent performance characteristics such as high transparency, low water affinity, good molding characteristics, substantial heat resistance and low birefringence. Low water affinity is particularly desirable in optical data storage media applications in which disk flatness is affected by water absorption. In “read through” applications successful employment of a particular optical plastic requires that it be readily molded into disks embossed with a series of very fine grooves and pits which govern critical aspects of data storage and retrieval. Replication of these grooves and pits during molding must occur with high precision and a high level of disk to disk uniformity must be achieved. Moreover the material itself must not stick to or foul the mold surfaces. Water affinity, molding characteristics, thermal and optical properties are properties of the material itself and will ultimately depend upon the structure of the optical polymer. Efforts to maximize desirable properties and repress undesirable properties in optical polymers have been intense. The chief means of discovery in this area has been through chemical synthesis and testing of new materials. Many different polymer types and structures have been prepared and evaluated. However, because each new application may require a different balance of material characteristics not currently provided by known materials, efforts directed to the discovery of new polymers has continued.
Silicone copolycarbonates as a class exhibit poor miscibility of the silicone and polycarbonate repeat units and a marked tendency toward segregation into predominantly silicone-containing and polycarbonate containing phases. This behavior limits the utility of silicone copolycarbonates. There exists a need for silicone copolycarbonate compositions which are, as defined herein, substantially single phase, which have excellent processability and low water affinity, and are suitable for use in high density optical recording media.
SUMMARY OF THE INVENTION
The present invention provides substantially single phase silicone copolycarbonates suitable for use in optical data storage applications. These and further embodiments of the invention will be more readily appreciated when considering the following disclosure and appended claims.
In one aspect, the invention relates to a substantially single phase silicone copolycarbonate comprising:
a. a repeat unit having structure I
 wherein R
1
and R
2
are each independently at each occurrence halogen, C
1
-C
6
alkyl or aryl,
m and n are each independently integers from 0-4,
W is a linking moiety selected from the group consisting of: a bond, a C
2
-C
18
alkylidene group, a C
3
-C
12
cycloalkylidene group, a carbon atom optionally substituted by one or two hydrogen atoms or one or two C
6
-C
10
aryl groups or one or two C
1
-C
18
alkyl groups; an oxygen atom, a sulfur atom, a sulfonyl (SO
2
) group and a carbonyl (CO) group; and
b. repeat units having structure II
 wherein R
3
is a C
2
-C
10
alkylene group optionally substituted by one or more C
1
-C
10
alkyl or one or more aryl groups; an oxygen atom or an oxyalkyleneoxy moiety such as:
—O—(CH
2
)
t
—O—
 or an oxyalkylene moiety such as:
—)—(CH
2
)
t
—  
 where t is an integer from 2-20;
and where R
4
and R
5
are each independently at each occurrence C
1
-C
6
alkoxy, C
1
-C
6
alkyl or aryl;
z and q are independently integers from 0-4; and further
R
6
, R
7
, R
8
and R
9
are each independently at each occurrence C
1
-C
6
alkyl, aryl, C
2
-C
6
alkenyl, cyano, trifluoropropyl or styrenyl;
and p is an integer from 0-20.
This invention further relates to methods of making these silicone copolycarbonates and methods for controlling physical properties of identically constituted silicone copolycarbonates by choice of preparation method. Two methods of preparation are disclosed. In Method 1 interfacial polymerization of the starting monomers with phosgene affords a product having a blocky structure and higher glass transition temperature than an identically constituted product produced by Method 2. In Method 2, reaction of an oligomeric, non-silicone-containing bischloroformate with a silicone-containing bisphenol affords a product with a random structure and glass transition temperature lower than an identically constituted product produced by Method 1. Still further, this invention relates to optical articles made from the silicone copolycarbonates and methods of making said optical articles.
DETAILED DESCRIPTION OF THE INVENTION
The present invention may be understood more readily by reference to the following description of preferred embodiments of the invention and the Examples included herein.
It is to be understood that this invention is not limited to specific synthetic methods or to particular compositions falling within the class of substantially single phase silicone copolycarbonates. In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings.
The singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that description includes instances where the event or circumstance occurs and instances where it does not.
“BPA” is herein defined as bisphenol A or 2,2-bis(4-hydroxyphenyl)propane. “BCC” is herein defined as 1,1-bis(4-hydroxy-3-methylphenyl) cyclohexane.
“BPI” is herein defined as 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
“BPZ” is herein defined as 1,1-bis-(4-hydroxyphenyl)cyclohexane
“C
g
” is the stress optical coefficient of a polymeric material in the glassy state, measured in Brewsters (10
−13
cm
2
/dyne)
“C
p
” represents the heat capacity of a material.
“Degree of oligomerization” as used herein refers to the value of r in structural formula IV.
“Identically constituted” as used herein refers to silicone copolycarbonates which have roughly the same molecular weight and which contain the same relative number of moles of repeat units I and II, said relative number of moles of repeat units I and II being determined by nuclear magnetic resonance spectroscopy (NMR). Two silicone copolycarbonates are defined herein as having roughly the same molecular weight when each exhibits an M
w
value which is within 10% of the M
w
value measured for the other composition by gel permeation chromatography (gpc) using polystyrene standards.
“MTBAC” is herein defined as methyltributyl ammonium chloride.
“Optical data storage media” or an “optical data storage medium” refers to an article which may be encoded with data and which is read by optical means.
“Optical articles” as used herein include optical disks and optical data storage media, for example a rewritable or read only compact disk (CD), a digital versatile disk, also known as DVD, random access memory disks (RAM), magneto optical (MO) disks and the

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