Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1997-07-03
1999-08-03
Buttner, David
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525 91, 525242, 5253333, 525386, C08G 6308
Patent
active
059326638
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The present invention relates to a novel block copolymer composed of at least one block A, constructed from units of styrene or its technical equivalents (a), and at least one block C, constructed from units of a cyclic lactone (c), the block copolymer being obtainable by anionic polymerization, and to a process for its preparation. More particularly, the invention relates to block polymers based on .epsilon.-caprolactone as cyclic lactone (c).
The invention further relates to the use of the block copolymers of the invention for producing shaped articles, films or fibers and to the shaped articles, films or fibers obtained from the block copolymers of the invention. The invention further relates to the use of the block copolymers as compatibilizers.
Block copolymers containing units derived from styrene and diene monomers are customarily prepared by anionic polymerization. It is also known to react (cap) the living chain ends of polybutadiene remaining from the anionic polymerization with certain coupling reagents before further reaction with polymers such as poplystyrene. This has the advantage that the desired block copolymers are obtained more rapidly and that multifunctional coupling reagents can be used to construct branched block copolymers (see for example Morton, Anionic Polymerisation-Principles and Practice, Academic Press, New York, London, 1983, pages 226-230).
Hsieh, Journal of Applied Polymer Science, 22 (1978), 1119, describes block copolymers of styrene, butadiene and lactones. Initially, living polystyrene-block-polybutadiene (Li) is prepared. Before reaction with the lactone, the living chain ends are converted into an alkoxy group to prepare the chain end for the attachment of the lactone.
C. Auschra (thesis, Mainz 1992) disclosed block copolymers composed of styrene, butadiene and methyl methacrylate blocks. Following the preparation of polystyrene-b-polybutadiene (Li), the living chain ends of the butadiene block are capped with diphenylethylene and then reacted with methyl methacrylate. The diphenylethylene has the effect of reducing the reactivity of the living chain end and so of reducing secondary reactions. It is true that the block copolymers obtainable by this method have high molecular weights and a narrow molecular weight distribution, but the reaction of the chain ends with the diphenylethylene is problematic, since it is frequently too slow and not quantitative. Yet a substantially quantitative reaction is necessary, if secondary reactions are to be suppressed and high yields are to be obtained. This is especially necessary for processes which are to be practiced on an industrial scale.
It is an object of the present invention to provide a polymerization process of the type mentioned at the beginning whereby such block copolymers can be prepared rapidly, in high yields and purities and also with a narrow molecular weight distribution.
We have found that this object is achieved by reacting the living chain end remaining following the construction of block A with a diarylethylene of the general formula I ##STR1## where Ar.sup.1 and Ar.sup.2 are independently of each other aryl with or without C.sub.1-C.sub.8 -alkyl or C.sub.1 -C.sub.8 -alkoxy or halogen single or multiple substitution, under anionic polymerization conditions before reaction with the monomer (c).
In an advantageous embodiment of the invention, the reaction with the diarylethylene I or the block C is preceded by initially, in a conventional manner, attaching to the living end of block A a further block B, constructed from units (b) of a diene, to obtain copolymers of the type of the known rubber-elastic styrene-butadiene-block copolymers, which are then modified by means of block C. To be able to bind the diarylethylene I to the block B, however, it has been found to be desirable first to attach at least one further monomer unit (a) to block B. From experience it is sufficient for from 1 to 5 equivalents of monomer unit (a) to be attached.
The diarylethylene I used is conveniently the simplest compo
REFERENCES:
patent: 3890408 (1975-06-01), Schepers
patent: 4360643 (1982-11-01), Naylor
patent: 5100943 (1992-03-01), Katoh
Balsamo-Hernandez Vittoria
Brinkmann Susanne
Gottschalk Axel
Jung Karsten
Stadler Raimund
BASF - Aktiengesellschaft
Buttner David
LandOfFree
Block copolymer and preparation thereof by anionic polymerizatio does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Block copolymer and preparation thereof by anionic polymerizatio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Block copolymer and preparation thereof by anionic polymerizatio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-850159