Process for the preparation of polymerisates of vinyl aromatic c

Details Process for the preparation of polymerisates of vinyl aromatic c Process for the preparation of polymerisates of vinyl aromatic c

1998-06-02

2000-09-19

Teskin, Fred

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

Synthetic resins

Polymerizing in two or more physically distinct zones

526 88, 526153, 526160, 526346, 26421124, 26433117, C08F 202, C08F 1208

Patent

active

061213918

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to processes for the preparation of polymers of vinylaromatic compounds at from -80 to 150.degree. C. in the presence of metallocene catalyst systems.
The present invention furthermore relates to the use of the resulting polymers for the production of fibers, films and moldings and to the fibers, films and moldings obtainable therefrom.
Owing to their property profile, polymers of vinylaromatic compounds, in particular polystyrenes, are used in many areas, for example as packaging materials or as insulating coatings for metals or plastics, especially for electrical applications.
EP-A 584 646 describes processes for evaporation of syndiotactic polystyrene in continuously operated, horizontal reactors, but catalyst mixtures and monomer have to be repeatedly metered in for efficient conversion of monomers. Furthermore, the activators have to be metered in separately from the monomers and from the transition metal catalysts.
EP-A 379 128 likewise discloses a process for the preparation of syndiotactic polystyrene in continuously operated, horizontal reactors. However, there is an acute danger of sticking during discharge from the reactor, with the result that continuous operation cannot be guaranteed. In addition, the degree of self-purging is very low in this process.
It is an object of the present invention to provide novel processes for the preparation of polymers of vinylaromatic compounds which processes do not have the stated disadvantages and in particular are not very complicated in terms of process engineering.
We have found that this object is achieved by processes for the preparation of polymers of vinylaromatic compounds at from -80 to 150.degree. C. in the presence of metallocene catalyst systems, wherein polymerization is carried out in one stage with the use of a closely intermeshing twin-screw extruder having corotating screws.
We have also found the use of the resulting polymers for the production of fibers, films and moldings, and the fibers, films and moldings obtainable therefrom.
Particularly suitable vinylaromatic compounds are compounds of the formula I ##STR1## wherein R.sup.1 is hydrogen or C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.12 -alkyl, C.sub.6 -C.sub.18 -aryl or halogen or two neighboring radicals together form a cyclic group of 4 to 15 carbon atoms.
Preferably used vinylaromatic compounds of the formula I are those in which phenyl or two neighboring radicals together form a cyclic group of 4 to 12 carbon atoms, so that examples of compounds of the formula I are naphthalene derivatives or anthracene derivatives.
Examples of such preferred compounds are: 4-vinylbiphenyl, 2-vinylnaphthalene and 9-vinylanthracene.
Mixtures of different vinylaromatic compounds may also be employed, but preferably only one vinylaromatic compound is used.
Particularly preferred vinylaromatic compounds are styrene and p-methylstyrene.
The preparation of vinylaromatic compounds of the formula I is known per se and is described, for example, in Beilstein 5, 367, 474 and 485.
In the novel processes, preferably used metallocene complexes A) are those of the formula II ##STR2## wherein R.sup.7 to R.sup.11 are each hydrogen, C.sub.1 -C.sub.10 -alkyl, 5- to 7-membered cycloalkyl, which in turn may carry C.sub.1 -C.sub.6 -alkyl groups as substituents, or C.sub.6 -C.sub.15 -aryl or arylalkyl, or two neighboring radicals together may furthermore form a cyclic group of 4 to 15 carbon atoms, or Si(R.sup.12).sub.3, -C.sub.10 -cycloalkyl, metal of the lanthanide series, C.sub.6 -C.sub.15 -aryl, C.sub.1 -C.sub.10 -alkoxy or C.sub.1 -C.sub.15 -aryloxy +z.sub.3 +z.sub.4 +z.sub.5 corresponding to the valency of M minus 1.
Particularly preferred metallocene complexes of the formula II are those in which titanium, zirconium or hafnium, in particular titanium, -alkoxy or halogen.
Examples of such preferred metallocene complexes are:
Metallocene complexes as described in EP-A 584 646 may also be used.
Mixtures of different metallocene complexes may also be employed.
The synthesis of such complex

REFERENCES:
patent: 4794096 (1988-12-01), Ewen
patent: 5164479 (1992-11-01), Funaki et al.
patent: 5254647 (1993-10-01), Yamamoto et al.
patent: 5597879 (1997-01-01), Ase et al.
Jrl. Org. Chem., 369, 1989, p. 359-370.
Beilstein, 5, 367, 474, 485.

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