Nucleating agents for stereoregular elastomeric butene-1 polymer compositions

Claim 1

The method for promoting crystallization from the melt of a stereoregular elastomeric homopolymer of butene-1 having reduced crystallinity due to enchained syndiotactic and isotactic structures and having the following properties: ______________________________________ Solubility in refluxing diethyl ether, % wt <10 Crystallinity, by X-ray diffraction (Form I), % 25-40 M.sub.n 20,000-300,000 M.sub.w 150,000-2,200,000 M.sub.w /M.sub.n 4-8 Melting Point, Form I, °C. ˜100-118 Melting Point, Form II, °C. ˜98-110 Time for Crystallization ˜15-20 minutes Temperature of Crystallization ˜30-45° C. ______________________________________ characterized in that there is added to a composition comprising said stereoregular elastomeric polymer an amount in the range from about 0.01 to 1% by weight of a low molecular weight high density polyethylene nucleating agent having utility for both promoting rapid crystal nucleation in said stereoregular elastomeric polymer of butene-1 and forming a resultant composition with utility for forming a product with a uniform microstructure said high density polyethylene nucleating agent having a density of about 0.94 to 0.97 g/cc, a molecular weight in the range from 850 to 3000 and a melt index greater than 5000 dg/min.

Claim 2

The method for promoting crystallization from the melt of a stereoregular elastomeric homopolymer of butene-1 having reduced crystallinity due to enchained syndiotactic and isotactic structures and having the following properties: ______________________________________ Solubility in refluxing diethyl ether, % wt <10 Crystallinity, by X-ray diffraction (Form I), % 25-40 M.sub.n 20,000-300,000 M.sub.w 150,000-2,200,000 M.sub.w /M.sub.n 4-8 Melting Point, Form I, °C. ˜100-118 Melting Point, Form II, °C. ˜98-110 Time for Crystallization ˜15-20 minutes Temperature of Crystallization ˜30-45° C. ______________________________________ characterized in that there is added to a composition comprising said stereoregular elastomeric polymer an amount in the range from about 0.01 to 1% by weight of a low molecular weight high density polyethylene nucleating agent having utility for both promoting rapid crystal nucleation in said stereoregular elastomeric polymer of butene-1 and forming a resultant composition with utility for forming a product with a uniform microstructure said high density polyethylene nucleating agent having a density of about 0.94 to 0.97 g/cc, a molecular weight in the range from 850 to 3000 and a melt index greater than 5000 dg/min.