China Petroleum & Chemical Corporation

Beijing Research Institute of Chemical Industry, China Petroleum & Chemical Corporation

China Petrochemical & Chemical Corporation

China Petroleum & Chemical Corporation and Beijing Research Institute of Chemical Industry

Luqiang Yu

Shijun Zhang

Meifang Guo

Jinliang Qiao

Zhichao Yang

Wenbo Song

Liangshi Wang

Honghong Huang

Jianjun Yin

Yang Liu

Wei Zhang

Kai Xu

Tao Liu

Qiang Li

Xi Wang

Hao Tang

Jiangbo Chen

Peng Guo

Meng Xu

Zhong Tan

Hua Yin

Jingbo Shao

Liying Zhang

Liqiu Chu

Huijie Hu

Hongwei Shi

Hui Quan

Mingfu Lyu

Yiqing Bai

Dali Gao

Yaohui Xu

Jianye Liu

Xiaomeng Zhang

Hao Zou

Mu Dong

Yihui Xu

Yun Lyu

Yujing Tang

Jianxin Zhang

Qingquan Yang

Liping Hou

Lusheng Wang

Huan Xu

Wenjun Wei

Jie Zou

Rongmei Liu

Qingshan Ma

Peiqian Yu

Zengyue Dai

Kang Sun

Qinyu Tong

Yafeng Du

Ruxian Li

Jianfang Sheng

The invention discloses a process for preparing high-performance propylene polymers, the process utilizing a high activity, highly stereoselective Ziegler-Natta catalyst and two or more stages of polymerization carried out under different hydrogen concentrations to prepare propylene polymers having broad molecular weight distribution, wherein non-uniformness of isotacticity of molecular chains of the final propylene polymers is improved by adjusting or controlling stereoselectivity of catalytic active sites under different hydrogen concentrations, namely, making the low molecular weight fraction of the polymers having a higher isotacticity and making the high molecular weight fraction of the polymers having a lower isotacticity, thereby overcoming the drawbacks of the propylene polymers having broad molecular weight distribution known in the art. The resulting final polymers have excellent combined properties, in particular, remarkably improved mechanical properties.

Process for preparing high-performance polypropylenes

Disclosed herein are a polypropylene with narrow molecular weight distribution and a process for preparing the same in a reactor using a Ziegler-Natta catalyst.

Polypropylene with narrow molecular weight distribution range and processes for preparation thereof

A polyethylene composition comprising an ethylene/&#x3b1;-olefin copolymerized linear low density polyethylene, wherein the polyethylene composition has a Mw of from 100,000 g/mol to 200,000 g/mol, a Mw/Mn of from 4.0 to 9.0, a Mz/Mw of from 4.0 to 7.0, and a Mz+1/Mw of from 4.5 to 13.5, is provided. A film formed of the polyethylene composition is also provided.

Polyethylene compositions and films formed therefrom

Disclosed herein is a polymerization method of propylene, which can prepare a propylene homopolymer with both high fluidity and high rigidity as well as a propylene/&#x3b1;-define copolymer having both high fluidity and a good rigidity-toughness balance by, for example, control of polymerization steps and elevation of polymerization temperature, while the catalyst still maintains a relatively high polymerization activity.

Methods for preparation of propylene polymers

The present invention provides a process for preparing high melt strength propylene polymer by direct polymerization, comprising that a propylene polymer with wide molecular weight distribution and containing 'very high molecular weight fraction' can be prepared by controlling the species and ratios of the external electron donors in the Ziegler-Natta catalyst system at different reaction stages according to the requirement for different molecular weight fractions in the different propylene polymerization stage of the series operation, and said polymer has excellent mechanical properties, especially with very high melt strength. The present invention also provides a propylene homopolymer with high melt strength, comprising the following features: (1) the MFR is 0.2-10 g/10 min at 230&#xb0; C. with a load of 2.16 kg; (2) the molecular weight distribution M/Mis 6-20; (3) the content of the fraction with a molecular weight higher than 5,000,000 is higher than or equal to 0.8 wt %; (4) M/Mis higher than or equal to 70. Said homopolymer can be used in the preparation of foam products, thermoforming products, biaxial stretching films, blown films and blow-molded products.

Propylene homopolymer having high melt strength and preparation method thereof

The present invention provides a propylene polymer composition for producing a biaxially oriented film, comprising propylene random copolymer and propylene homopolymer; wherein the propylene random copolymer is a copolymer of propylene and ethylene, optionally comprising one or more alpha-olefins of C-C; the propylene polymer composition has an overall isotacticity index, as determined by nuclear magnetic resonance method, of greater than or equal to 96.5%, and an ethylene content of greater than 0.3 wt %; and wherein, the melt flow rate of the propylene random copolymer is lower than that of the propylene homopolymer. The biaxially oriented polypropylene film produced by the propylene polymer composition of the present invention exhibits excellent physical properties, and has, in the absence of any stiffening agent, relatively higher modulus and stiffness. Moreover, the process for producing the biaxially oriented polypropylene film is featured with a good film-forming stability and a high film-forming stretching speed.

Propylene polymer composition and oriented film prepared thereby

Growing community of inventors

Beijing, China

Luqiang Yu