Amorphous vinyl cyclohexane polymers

Details Amorphous vinyl cyclohexane polymers Amorphous vinyl cyclohexane polymers

2000-08-08

2002-04-02

Zitomer, Fred (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S283000, C526S308000, C526S319000, C526S328000, C526S335000, C526S339000, C526S340200, C526S340300

Reexamination Certificate

active

06365694

ABSTRACT:

The present invention relates to polymers and co-polymers based on vinyl cyclohexane (VCH) with predominantly syndiotactic configuration and a process for their manufacture and their use as optical material. The materials may be processed into moulded bodies by extrusion or injection moulding and are particularly suitable as substrate for optical data storage media such as compact discs, video discs, re-writable optical discs.
Transparent plastics such as aromatic polycarbonate, polymethyl methacrylate or polystyrene may be used as substrate for optical data storage media. Addition co-polymers comprising ethylene and a norbornene derivative or a tetracyclododecene derivative and hydrogenated products of ring-opened metathesis polymers comprising norbornene or tetracyclododecene are also considered.
None of the current substrate materials may, however, be used without restriction for very high data storage densities (>5, particularly >10 Gbytes related to a disc of 120 mm diameter). Very low birefringence and water absorption, high heat deflection temperature, accompanied by adequate mechanical properties and low melting viscosity, are simultaneously required for this purpose.
Although aromatic polycarbonates have very good mechanical properties and heat deflection temperature, their birefringence and water absorption are too high.
The birefringence of polystyrene is too high and its heat deflection temperature too low.
The water absorption of polymethyl methacrylate is too high and its dimensional stability too low. The birefringence of addition co-polymers comprising ethylene and a non-polar norbornene or tetracyclododecene is low and they have virtually no water absorption.
These materials are very expensive to produce, however. The materials may only be produced in optically pure quality with great difficulty. The presence of gel contents also reduces their applications as optical materials. Considerable technical outlay is involved in separating the catalysts and co-catalysts.
Optical materials comprising a hydrogenation product of a polymer comprising an alkenyl-aromatic hydrocarbon compound or a co-polymer thereof are described in GB 933,596 (=DE-AS 1 131 885), EP-A 317 263, U.S. Pat. Nos. 4,911,966 and 5,178,926. There is no reference to the configuration.
Hermann Staudinger was the first to describe the hydrogenation of polystyrene in 1929. More recent patent literature concerns the basic micro-structure of polyvinyl cyclohexane and/or hydrogenated polystyrene. The prior art is that amorphous vinyl cyclohexane polymers have an atactic configuration and crystalline VCH (vinyl cyclohexane) polymers either isotactic or syndiotactic configuration (EP-A 0 322 731, EP-A 0 423 100, U.S. Pat. Nos. 5,654,253; 5,612,422; WO 96/34896). Isotactic PVCH (polyvinyl cyclohexane) is produced in the presence of Ziegler catalysts and has a high melting point (J. Polym. Sci., A2, 5029 (1964). EP-A 0 322 731 describes that vinyl cyclohexane polymers with syndiotactic configuration by hydrogenation of syndiotactic polystyrene are crystalline, wherein the quantity of the diads is at least 75% and the quantity of the pentads at least 30%. WO 94/21694 describes a process for producing hydrogenated poly(alkenyl-aromatic) polymers and poly(alkenyl-aromatic)/polydiene block co-polymers. Syndiotactic polystyrene is mentioned in general terms.
Processes which lead to isotactic, syndiotactic and atactic hydrogenated polystyrene which have the material properties known hitherto are described in WO 94/21694, U.S. Pat. No. 5,352,744, wherein specific catalysts are used. Processes for the hydrogenation of atactic polystyrene to produce atactic hydrogenated polystyrene by the use of specific catalysts are described in U.S. Pat. Nos. 5,654,253; 5,612,422; WO 96/34896.
Atactic polymers are regular polymers. By definition they have the possible configurative base units in equal quantities, with ideal-random distribution from molecule to molecule (TUPAC). They are distinguished by the same number of iso-and syndiotactic diads. An amorphous material with only one glass stage with no crystalline content is described.
The present invention provides a polymer or co-polymer based on vinyl cyclohexane, wherein olefins, acrylic acid derivatives, maleic acid derivatives, vinyl ethers or vinyl esters may be used in production as co-monomers, with syndiotactic configuration, characterized in that the quantity of diads is greater than 50.1% and less than 74%. The polymers based on vinyl cyclohexane are amorphous polymers.
The polymers according to the invention are distinguished by, high transparency, low birefringence and high heat deflection temperature and may therefore be used as substrate material for optical data storage media. Because of its crystallinity the known, isotactic PVCH is unsuitable for optical applications.
The invention provides hydrogenated products of polystyrene which lead to an amorphous hydrogenated polystyrene with an excess of the racemic (syndiotactic) diads.
The vinyl cyclohexane polymer of this invention is a new amorphous polymer with a defined stereostructure which is distinguished by the predominant occurrence of the racemic diads configuration and may be efficiently produced by the process described.
A polymer based on vinyl cyclohexane is preferred with the repeating structural unit of formula (I)
in which
R
1
and R
2
independently of each other stand for hydrogen or C
1
-C
6
alkyl, preferably C
1
-C
4
alkyl, and
R
3
and R
4
independently of each other stand for hydrogen or for C
1
-C
6
alkyl, preferably C
1
-C
4
alkyl, particularly methyl and/or ethyl, or R
3
and R
4
jointly stand for alkylene, preferably C
3
or C
4
alkylene (fused 5 or 6-membered cycloaliphatic ring),
R
5
stands for hydrogen or C
1
-C
6
alkyl, preferably C
1
-C
4
alkyl,
R
1
, R
2
and R
5
independently of each other stand in particular for hydrogen or methyl.
Apart from the stereoregular head-to-tail linkage, the linkage may have a small content of head-to-head linkage. The amorphous, predominantly syndiotactic polymer based on vinyl cyclohexane may be branched via centres and may have a stellar structure for example.
The following may preferably be used in the polymerization of the starting polymer (optionally substituted polystyrene) and be co-incorporated into the polymer as co-monomers: olefins with in general 2 to 10 C atoms, such as for example ethylene, propylene, isoprene, isobutylene, butadiene, C
1
-C
8
, preferably C
1
-C
4
alkyl esters of acrylic and/or methacrylic acid, unsaturated cycloaliphatic hydrocarbons, e.g. cyclopentadiene, cyclohexene, cyclohexadiene, optionally substituted norbornene, dicyclopentadiene, dihydrocyclopentadiene, optionally substituted tetracyclododecenes, nucleus-alkylated styrenes, &agr;-methylstyrene, divinyl benzene, vinyl esters, vinyl acids, vinyl ethers, vinyl acetate, vinyl cyanides such as for example acrylonitrile, methacrylonitrile, maleic anhydride and mixtures of these monomers.
The amorphous vinyl cyclohexane polymer according to the invention has a syndiotactic diad content, determined by two-dimensional NMR spectroscopy, of 50.1 to 74%, preferably of 52-70%. Methods for microstructure elucidation using
13
C-
1
H correlation spectroscopy of the methylene carbon atoms of a polymer backbone are generally known and are described by A. M. P. Ros and O. Sudmeijer for example (A. M. P. Ros, O. Sudmeijer, Int. J. Polym. Anal. Charakt. (1997) 4, 39).
The signals of crystalline isotactic and syndiotactic polyvinyl cyclohexane are determined by means of two-dimensional NMR spectroscopy. The methylene-carbon atom (in the polymer backbone) of the isotactic polyvinyl cyclohexane splits into two separated proton signals in the 2-D CH correlation spectrum and exhibits the pure isotactic diad configuration. In contrast, for the carbon atom C 1, syndiotactic polyvinyl cyclohexane exhibits only one signal in the 2-D CH correlation spectrum. The amorphous syndiotactically rich polyvinyl cyclohexane according to the invention has an integral intensity

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