Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Treating polymer containing material or treating a solid...
Patent
1989-05-11
1991-12-10
Teskin, Fred
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Treating polymer containing material or treating a solid...
528481, 528487, 528491, 528494, 528496, 528497, 528503, 264216, 4273855, C08F 612
Patent
active
050719530
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Field of Technology
The present invention relates to a method for the preparation of an amorphous styrene-based polymer having a substantially syndiotactic structure and a method for shaping the polymer. The invention also relates to a method for the modification of a shaped article of the styrene-based polymer.
2. Background Technology
Known method in the prior art for the preparation of a styrene-based polymer includes the methods by the free-radical polymerization, cationic polymerization, anionic polymerization, polymerization by using a transition metal complex as the catalyst, radiation polymerization and the like. It is usual, however, that styrene-based polymers are prepared by the method of free-radical polymerization.
The styrene-based polymers prepared by the radical polymerization method have a stereospecificity of atactic structure in the molecular configuration and they are shaped by a variety of shaping methods such as injection molding, extrusion molding, blow molding, vacuum forming, casting and the like into shaped articles of different forms widely used in household electric appliances, office instruments, household commodities, containers for packaging, toys, furnitures, synthetic papers and other industrial materials.
The inventors have previously discovered that styrene-based monomers can be polymerized by using a catalyst composed of a special transition metal compound and an organic aluminum compound to give a styrene-based polymer having a stereospecificity of substantially syndiotactic structure in the crystallinity. Although these styrene-based polymers having a syndiotactic structure have physical and chemical properties quite different from those of the above mentioned polymers having an atactic structure and possess excellent characteristics in several respects, they have problems in the method for shaping into articles to which conventional methods of handling are hardly applicable because the extremely high melting point of the polymer as a consequence of the high crystallinity necessitates thermal molding undertaken at a higher temperature eventually to cause thermal degradation of the polymer and the behavior of the polymer in melting is quite different from that of the conventional polymers having an atactic structure necessitating a shaping method using a special solvent.
In view of the above described problems, an object of the present invention is to prepare a styrene-based polymer having a stereospecificity of substantially syndiotactic structure and having excellent moldability suitable for thermal molding at a relatively low temperature.
Another object of the present invention is to efficiently shape the thus prepared styrene-based polymer having good moldability and still another object thereof is to modify the thus shaped article of the styrene-based polymer.
DISCLOSURE OF THE INVENTION
Namely, the present invention provides:
a method for the preparation of an amorphous styrene-based polymer having a substantially syndiotactic structure which comprises dissolving a styrene-based polymer having a substantially syndiotactic structure (it may be referred to hereinbelow as the starting styrene-based polymer) in a solvent and then separating and recovering the polymer from the solution (preparation method I);
a method for the preparation of an amorphous styrene-based polymer having a substantially syndiotactic structure which comprises melting the above mentioned starting styrene-based polymer with heating or dissolving the same with heating in a solvent followed by quenching (preparation method II); a method for shaping the styrene-based polymer which comprises casting, spreading or applying the solution of the styrene-based polymer obtained in the course of the above described preparation method I followed by evaporation of the solvent (shaping method I);
a method for shaping the styrene-based polymer which comprises melting the above mentioned starting styrene-based polymer with heating or dissolving the same with heating in a solvent followed by
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Ishihara et al., Synthesis and Properties of Polystyrene with New Stereoregularity, Polymer Preprints, 35(2).
Ishihara et al., Macromolecules, 19, 2465-2466, 1986.
Billmeyer, Jr., Textbook of Polymer Science, 2nd ed., Wiley-Interscience, 1971, 23-24.
Introduction to Makromol. Chem., (Seizo Okamura et al.), May 1, 1970, Kagakudojin, pp. 40-48, (Translation of 2.2, Molecular Weight and Distribution of Molecular Weight of High Molecules).
Kuramoto Masahiko
Nakano Akikazu
Sawada Michihiro
Suzuki Masakazu
Idemitsu Kosan Company Limited
Teskin Fred
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