Propylene elastomer and process for preparation thereof

Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...

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Details

526126, 526127, 526132, 526134, 526153, 526160, 526161, 526170, 526943, C08F21008, C08F 4642

Patent

active

056774087

DESCRIPTION:

BRIEF SUMMARY
This application is based on International Application PCT/JP94/01997, filed Nov. 29, 1994.


TECHNICAL FIELD

The present invention relates to a novel propylene elastomer excellent in rigidity, heat resistance, scratch resistance, transparency, heat sealing properties and blocking resistance.


BACKGROUND ART

Because of their excellent scratch resistance, transparency, heat resistance and heat sealing properties, propylene elastomers are used for films and sheets.
Of various propylene elastomers, propylene elastomers which are copolymers of propylene and 1-butene have been conventionally prepared using solid titanium catalysts or metallocene catalysts comprising metallocene compounds such as zirconium and hafnium and alkylaluminoxane.
However, the conventional propylene elastomers prepared as above are not always satisfactory in heat sealing properties, blocking resistance and heat resistance. Therefore, the advent of a propylene elastomer excellent in not only shock-absorbing properties, heat resistance, transparency and rigidity but also heat sealing properties and blocking resistance has been desired.
Under the circumstances, the present inventors have studied on the propylene elastomers which are copolymers of propylene and 1-butene. As a result, they have found that a propylene elastomer having a high triad tacticity of the head-to-tail enchained propylene unit sequences (the sequences are formed from head-to-tail enchained propylene units, and all the branch directions of the methyl groups are the same) and having high stereoregularity exhibits the above-mentioned excellent properties. They have also found that such propylene elastomer can be efficiently prepared by the use of a specific metallocene compound catalyst component, and accomplished the present invention.
The present applicant has already disclosed a propylene elastomer in which propylene and other .alpha.-olefin are head-to-tail enchained regularly in Japanese Patent Laid-Open Publication No. 119212/1987. This propylene elastomer is prepared by the use of a metallocene compound such as ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride, and it has a higher melting point as compared with the propylene elastomer of the present invention if they are the same in the monomer composition (comonomer ratio).


DISCLOSURE OF INVENTION

The propylene elastomer of the invention has the following properties: 95% by mol and units derived from 1-butene in amounts of 5 to 50% by mol; propylene unit-butene unit triad sequences consisting of head-to-tail enchained propylene units and butene units and containing propylene units as the second units are measured on the side chain methyl groups of the propylene units of the second units in the triad sequences using .sup.13 C-NMR spectrum (hexachlorobutadiene solution, based on tetramethylsilane), the area of peaks shown in the region of 21.0 to 21.9 ppm is not less than 90% based on the total area of all peaks shown in the region of 19.5 to 21.9 ppm being 100%; 135.degree. C., of 0.1 to 12 dl/g; by gel permeation chromatography (GPC), of not more than 3; and the copolymerized monomer sequence distribution, of 1.0 to 1.5.
In the propylene elastomer of the invention, the parameter B value, which indicates randomness of the copolymerized monomer sequence distribution, is preferably 1.0 to 1.3.
In addition to the properties (1) to (5), the propylene elastomer of the invention is desired to further have the following properties: scanning calorimeter, of 60.degree. to 140.degree. C., and the melting point Tm and a 1-butene constituent unit content M (% by mol) in the elastomer satisfy the following relation: diffractometry, and a 1-butene constituent unit content M (% by mol) in the elastomer satisfy the following relation:
Such a propylene elastomer of the invention as mentioned above is obtained by copolymerizing propylene and 1-butene in the presence of an olefin polymerization catalyst comprising: ##STR1## wherein M is a transition metal of Group IVa, Group Va or Group VIa of the periodic table, g

REFERENCES:
patent: 4168361 (1979-09-01), Oda et al.
patent: 5081322 (1992-01-01), Winter et al.
patent: 5336746 (1994-08-01), Tsutsui et al.
patent: 5455365 (1995-10-01), Winter et al.
patent: 5491207 (1996-02-01), Hoel
patent: 5504172 (1996-04-01), Imuta et al.

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