Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1997-06-23
1999-07-06
Michl, Paul R.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525269, C08F29700
Patent
active
059198672
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an A-B-A type of block copolymer consisting of polymer block A of a (meth)acrylate and polymer block B of an olefin, and a preparation process thereof.
BACKGROUND ART
Polyolefins have a drawback that they have a lower adhesive property, a lower printing property and a lower compatibility with other polymers due to having no polar groups. To overcome the drawback, copolymerization of an olefin with a polar monomer has been attempted. In addition, it is known that an olefin may be copolymerized with methyl methacrylate for the purpose of improvement in an impact resistance, improvement in a flexibility, reduction of a water absorption and imparting a surface hydrophobicity.
Processes for preparing these copolymers have been disclosed; for example, JP-A 59-43003 or JP-A 64-14217 which has disclosed a process for preparation of a copolymer using a titanium catalyst or a nickel catalyst, respectively. Both processes have a drawback that they require a large amount of a Lewis acid or alumioxane as a co-catalyst.
JP-A 1-201302, JP-A 1-201304 and JP-A 63-43914 have disclosed processes that a polyolefin is modified at its ends and is then block-copolymerized with a (meth)acrylate.
However these processes have a drawback that an introduction ratio of the modified ends is low, so that homopolymers of the (meth)acrylate may be produced as by-products.
Furthermore, JP-A 3-255116 and JP-A 4-53813 have disclosed processes that a block copolymer of ethylene-(meth)acrylate may be produced using a monofunctional, trivalent, rare earth compound. However, the former process does not provide a copolymer containing (meth)acrylate in a high proportion, while the latter process provide products with a wide distribution of molecular weight, i.e., Mw/Mn>2, due to a chain-transfer reaction during the polymerization of ethylene and gives homopolymers of ethylene as byproducts. In addition, since ethylene does not react with a propagating end of (meth)acrylate, these processes can provide only two-component block copolymers of ethylene-(meth)acrylate.
Recently, difunctional rare earth complexes as a polymerization initiator have been proposed for preparation of homopolymers of ethylene or copolymer of ethylene with other monomers. Specifically, William J. Evans et al. have polymerized ethylene using a difunctional rare earth complex as an initiator (J.Am.Chem.Soc., 1990, 112, pp.2314-2324). Bruce M. Novak and Lisa S. Boffa have obtained a three-component block copolymer of poly(methyl methacrylate) block-poly(ethyl acrylate) block-poly(methyl methacrylate) block, using a difunctional rare earth complex as an initiator (ACS Polymer Preprint., 35(2), 1994 and Boffa, MACRO AKRON '94, 117). Yasuda et al. have polymerized ethylene using a bivalent samarium complex as an initiator. (Polymer Preprints). Japan, Vol.43, No.6(1994)). These reports, however, do not imply an A-B-A type of block copolymer of this invention.
Generally, as described in "P. L. Watoson and T. Herskorvitz ACS symposium series No.212, p.459-479", it is known that a bivalent samarium complex makes ethylene polymerize according to the following formula (III).
Specifically, when both ends of a polymer produced are living ends, an A-B-A type of block copolymer may be produced by adding another monomer. ##STR1##
The present inventors have proposed the preparation of an A-B-A type of block copolymer consisting of ethylene and a (meth)acrylate in JP-A 6-306112 by applying the above concept, but the process has a drawback that a copolymer produced has a Mw/Mn of 4 to 6, indicating a wide distribution of molecular weight, and it produces a large amount of polymers as byproducts such as diblock copolymers and homopolymers of methyl methacrylate.
We have intensively attempted to solve the problems and finally discovered that a particular initiator may provide a three-component block copolymer of (meth)acrylate--olefin--(meth)acrylate having a narrow distribution of molecular weight, to achieve this invention.
DISCLOSURE OF INVENTI
REFERENCES:
patent: 4921901 (1990-05-01), Ueki
patent: 5132369 (1992-07-01), Yasuda
patent: 5489651 (1996-02-01), Novak
patent: 5527751 (1996-06-01), Inamatsu
patent: 5563219 (1996-10-01), Yasuda
patent: 5670580 (1997-09-01), Tazaki
H. Yasuda et al, "New Approach to Block Copolymerizations of Ethylene with Alkyl Methacrylates and Lactones by Unique Catalysis with Organolanthanide Complexex" Macromolecules, vol. 25, No. 19, 1992.
T. Kitayama et al, "PMMA-Block-Polyisobutylene-PMMA Prepared with Alpha, Omega-Dilithiated Polyisobutylene and its Characterization", Polymer Bulletin, No. 26, 1991.
Ige Hitoshi
Ihara Eiji
Tokimitsu Toru
Tone Seiji
Yanagase Akira
Michl Paul R.
Mitsubishi Rayon Co. Ltd.
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