This invention relates generally to low ethylene insertions into I-olefin polymers and processes for production of such polymers using unbridged fluxional metallocenes, primarily substituted aryl indenyl metallocenes, and more particularly to use of unbridged, fluxional, cyclopentadienyl or indenyl metallocene catalyst systems in methods of production of high melting point I-olefin homo- and co-polymers, particularly elastomeric crystalline and amorphous block homo- and co-polymers of I-olefins. The activity of fluxional unbridged metallocene polymerization catalysts containing at least one 2-arylindene ligand is increased 10× or more by the addition of small (typically 0.1-10 wt. %) amounts of ethylene to the polymerization system, which increase is termed the Polymerization Rate-Enhancement effect (PRE), which is measured in terms of an Ethylene Enhancement Factor (EEF) as a dimensionless ratio in the range of from about 1.1 to about 10 or above. The amount of ethylene included in the reaction system can be selected and controlled to be so small as to result in essentially minimal (<2 mole %) incorporation of ethylene units into the resulting elastomeric polymer and the molecular weight may be increased. Amounts of ethylene to generate the PRE effect may be greater than 0.1 wt. % and preferably range up to about 2 wt. %. However, if a polymer with more ethylene is desired, additional ethylene may be incorporated into the polymerization feed, including up to 10 to about 50 mole % based on olefin units. A second important aspect of this invention is the ability to use a PRE activity-enhancing amount of ethylene in an olefin polymerization without substantially affecting the physical properties of the elastomer. In a third important aspect of this invention, I-olefin elastomers are produced through incorporation of ethylene using unbridged fluxional catalyst systems which may not otherwise produce acceptable elastomeric homopolymers. This effect is termed the EPE effect, for Elastomeric Property-Enhancing effect. The EPE amount of ethylene required to produce such elastomers typically overlaps the PRE activity-enhancing amount. Incorporation of up to about 5 mole % or more of ethylene typically will produce an elastomeric polymer using such catalyst systems. Typical useful amounts of incorporated ethylene include about 1 to 3 mole %. Preferred polymers of this invention retain sufficient crystallinity to provide a high melting point (by DSC) of about 80° C., preferably above 100° C., including in the range of from about 120° C. to about 140° C. and above. Novel flexible &agr;-olefin homo and copolymers having elongation in excess of 600% and substantially no retained force are disclosed.
本发明涉及低
乙烯插入到I-烯烃聚合物中的方法以及使用非桥联流动
金属芳基
茚基
金属烯催化剂,主要是取代芳基
茚基
金属烯,特别是使用非桥联流动
环戊二烯基或
茚基
金属烯催化剂系统制备高熔点I-烯烃同聚物和共聚物,特别是I-烯烃的弹性结晶和非晶块同聚物和共聚物的制备方法。至少含有一个2-芳基
茚烯
配体的流动非桥联
金属烯聚合催化剂的活性通过向聚合体系中添加少量(通常为0.1-10重量%)的
乙烯而增加10倍或更多,该增加被称为聚合物化速率增强效应(PRE),其以
乙烯增强因子(EEF)的无量纲比率为衡量,范围从约1.1到约10或以上。可以选择和控制反应系统中包含的
乙烯量非常少,以至于在所得弹性聚合物中基本上不含有
乙烯单元(<2摩尔%),并且分子量可以增加。用于产生PRE效应的乙烯量可能大于0.1重量%,且最好在约2重量%范围内。但是,如果需要含有更多乙烯的聚合物,则可以在聚合反应中加入额外的乙烯,包括基于烯烃单位的10到约50摩尔%。本发明的第二个重要方面是,在烯烃聚合中使用PRE活性增强的乙烯量而不会显着影响弹性体的物理性质。在本发明的第三个重要方面中,通过使用非桥联流动催化剂系统,通过乙烯的插入来生产I-烯烃弹性体,否则这些催化剂系统可能不会产生可接受的弹性同聚物。该效应被称为EPE效应,用于弹性体性能增强效应。通常需要插入约5摩尔%或更多的乙烯来使用这种催化剂系统制备弹性聚合物。通常有用的插入乙烯量包括约1到3摩尔%。本发明的优选聚合物保持足够的晶体性,以提供约80℃的高熔点(通过
DSC),最好高于100℃,包括在约120℃至约140℃及以上的范围内。还公开了具有超过600%伸长率和基本无保留力的新型柔性α-烯烃同聚物和共聚物。