Process for preparing styrenic resin

Details Process for preparing styrenic resin Process for preparing styrenic resin

1997-01-27

1998-06-02

Teskin, Fred

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

Synthetic resins

Treating polymer containing material or treating a solid...

528487, 528491, 528495, 528499, 528501, 528502R, 524577, 264211, 26433115, C08J 318

Patent

active

057601720

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention relates to a process for preparing a styrenic resin, and more specifically, it relates to a method for effectively inhibiting the yellowing of pellets of a styrenic polymer powder having a syndiotactic configuration in the case that the styrenic polymer powder is volatilized and extruded by the use of an extruder to prepare the pellets, or a method for economically and efficiently decreasing a remaining volatile component such as an unreacted monomer in the pellets.


BACKGROUND ART

A styrenic polymer (hereinafter abbreviated to "SPS" sometimes) having a syndiotactic configuration obtained by improving a styrenic polymer having an atactic configuration is excellent in heat resistance and chemical resistance.
The group of the present inventors has already succeeded in the development of a styrenic polymer having a high syndiotacticity, and this group has further disclosed that the SPS can be obtained by the use of a catalyst comprising a titanium compound, a catalytic product (an alkylaluminoxane) of an organic aluminum compound and a condensing agent, or a coordinated complex compound comprising a cation and an anion in which a plurality of groups are bonded to a metal (Japanese Patent Application Laid-open Nos. 187708/1987 and 249503/1992).
The above-mentioned styrenic polymer is prepared by a non-solvent polymerization method or a slurry polymerization method, but in the case that the above-mentioned styrenic polymer is prepared by such a method, it is advantageous from the viewpoints of a catalytic activity and productivity that styrene is highly concentrated and then polymerized. However, this preparation is carried out by the use of a catalyst containing a metal such as Al, Ti or Fe, and therefore a large amount of a metallic component remains in the obtained polymer, depending upon the kind of selected catalyst. This remaining metallic component causes the deterioration of the molecular weight and color tone of the polymer. Accordingly, it has been desired to decrease the remaining catalytic component in the obtained polymer product by a deashing treatment (the removal of the remaining catalyst).
As this deashing treatment method, there are a method which comprises adding a deashing agent, a method which comprises swelling the polymer with a swelling agent, and a method which comprises raising a treatment temperature in each of these methods to improve a deashing efficiency.
However, these methods have some problems. For example, the deashing efficiency is poor, washing is required, and a stable operation is difficult to do.
That is to say, in the method which comprises adding the deashing agent for the treatment, a step for removing the deashing agent is essential, and for the sake of the removal, a large amount of a solvent must be used, which makes the preparation process intricate and increases the cost of facilities. In the method which comprises adding the swelling agent for the treatment, deactivation and deashing can be accomplished under relatively mild conditions, but the polymer might dissolve or cohere, depending upon the composition and conversion of the polymer, the composition of a treatment solution and a treatment temperature. Owing to this fact, a stable operation cannot be accomplished. In addition, since the polymer swells, a waste liquid containing a remaining catalyst solution gets into the polymer, and thus the amount of the metal cannot be decreased to a certain level or less.
Therefore, it has been desired to develop a method for stably and easily preparing the SPS which can effectively inhibit yellowing and which has good characteristics.
On the other hand, in the case that the abovementioned styrenic polymer can be prepared by a non-solvent polymerization method or a slurry polymerization method, about 0.1 to 50% by weight of a remaining volatile component such as an unreacted monomer is contained in the obtained polymer. Therefore, a drying volatilization treatment has been carried out as a post-treatment subsequent to the pol

REFERENCES:
patent: 3451462 (1969-06-01), Szabo et al.
patent: 3773740 (1973-11-01), Szabo
patent: 3799234 (1974-03-01), Skidmore
patent: 5166238 (1992-11-01), Nakano et al.
patent: 5292587 (1994-03-01), Funaki et al.
patent: 5321122 (1994-06-01), Kuramoto et al.
patent: 5380822 (1995-01-01), Skilbeck
Chemical Abstracts, vol. 123, No. 16, p. 100, AN-200776c, Oct. 16, 1995, JP-07 157 613, Jun. 20, 1995.
Database WPI, Derwent Publications, AN 91-114453, XP 002011175, & Chemical Abstract, vol. 115, No. 12, Sep. 23, 1991, JP-03 056 504, Mar. 12, 1991.

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