It is an object of the present invention to provide a process for producing a syndiotactic propylene polymer with high polymerization activity and high efficiency by a solution polymerization method without deposition of polymers (excluding a white state), and a production process capable of conducting the above production continuously, provided that these processes could not be attained conventionally.
The present invention is:
a process for producing a syndiotactic propylene polymer having a syndiotactic pentad fraction (rrrr fraction), as measured by
13
C-NMR, of at least 85%, a melting point (Tm), as measured by DSC, of from 145° C. to 170° C., and an intrinsic viscosity [η] of 0.1 to 10 dl/g, which process comprises a step (P
1
) of solution polymerizing propylene singly or propylene and at least one monomer selected from ethylene and an α-olefin having 4 to 10 carbon atoms at a polymerization temperature (T
R
) of from 30° C. to 250° C. in an inert hydrocarbon solvent in the presence of an olefin polymerization catalyst which comprises;
(A) a bridged metallocene compound represented by the following formula (I), and
(B) at least one compound selected from
(b-1) an organoaluminum oxy compound,
(b-2) a compound capable of forming an ion pair by reacting with the metallocene compound (A), and
(b-3) an organoaluminum compound.
in which M is a titanium atom or the like, Q is a halogen atom or the like, j is an integer of 1 to 4, R
a
and R
b
may be identically or differently a single nuclear or polynuclear hydrocarbon residue capable of forming a sandwich structure together with M, Y is a carbon atom or a silicon atom, and R
c
and R
d
may be the same or different from each other, is selected from hydrogen, a hydrocarbon group and a silicon atom-containing group and further may be bonded each other to form a ring.
本发明的目的是提供一种通过溶液聚合方法生产高聚合活性和高效率的顺-
丁烯聚合物的工艺,而不产生聚合物沉淀(不包括白色状态),以及能够连续进行上述生产的生产工艺,前提是这些工艺以往无法实现。本发明是:一种生产顺-
丁烯聚合物的工艺,其具有在13C-NMR中测量的顺-
丁烯五聚分数(rrrr分数)至少为85%,熔点(Tm)在145℃至170℃之间,固有粘度[η]为0.1至10 dl/g,其中该工艺包括以下步骤(P1):在惰性烃溶剂中,存在以下烯烃聚合催化剂的情况下,将
丙烯单独或
丙烯和至少一种选择自
乙烯和具有4至10个碳原子的α-烯烃的单体在聚合温度(TR)为30℃至250℃的条件下进行溶液聚合的步骤:(A)桥联的
金属茂化合物,其表示为以下公式(I):(B)至少选择自(b-1)
有机铝氧化合物,(b-2)能够通过与
金属茂化合物(A)反应形成离子对的化合物和(b-3)
有机铝化合物的化合物。其中,M是
钛原子或类似物,Q是卤素原子或类似物,j是1至4的整数,Ra和Rb可以是相同或不同的单核或多核碳氢残基,能够与M一起形成三明治结构,Y是碳原子或
硅原子,Rc和Rd可以相同或不同,选择自氢、碳氢基和含
硅原子的基团,且还可以彼此结合形成环。