Polypropylene with narrow distribution of molecular weight

A technology of molecular weight distribution and polypropylene, which is applied in the field of propylene polymers with narrow molecular weight distribution, can solve the problems of increasing product cost and so on

Active Publication Date: 2014-05-14
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The industrial method of preparing polypropylene with a narrow molecular weight distribution is usually obtained through peroxide degradation (so-called controlled rheology polypropylene), ...

Method used

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  • Polypropylene with narrow distribution of molecular weight
  • Polypropylene with narrow distribution of molecular weight
  • Polypropylene with narrow distribution of molecular weight

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0104] 1) Raw materials

[0105] Preparation of the main catalyst: After fully replacing the 16L pressure-resistant reactor with a stirrer with nitrogen, add 10L ethanol, 300mL 2-ethylhexanol, 11.2g iodine, 8g magnesium chloride and 640g magnesium powder into the reactor. While stirring, the temperature of the system was raised to 75° C. for reflux reaction until no more hydrogen gas was discharged. Stop the reaction, wash with 3L of ethanol, filter and dry to obtain dialkoxymagnesium carrier. The obtained dialkoxymagnesium carrier has a D50 of 30.2 μm, a span value of 0.81, and an m value of 0.015. Take 650 g of the above-mentioned dialkoxymagnesium carrier, 3250 mL of toluene and 65 mL of 2-isopropyl-2-isopentyl-1,3-dimethoxypropane to prepare a suspension. In a 16L pressure-resistant reaction kettle that has been repeatedly replaced by high-purity nitrogen, add 2600mL of toluene and 3900mL of titanium tetrachloride, raise the temperature to 80°C, then add the prepared sus...

Embodiment 2

[0115] 1) raw material (with embodiment 1)

[0116] 2) test device (with embodiment 1)

[0117] 3) Test conditions

[0118] Step (1) pre-polymerization: the reaction pressure is 2.5MPa, the reaction temperature is 10°C, and the reaction time is 12 minutes; the feed amount of the main catalyst and triethylaluminum are 0.4g / hour and 0.058mol / hour respectively; the feed amount of propylene 10 kg / hour.

[0119] (2) step gas phase polymerization: 91 DEG C of reaction temperature, reaction pressure is 2.3MPa, and reaction time is 60 minutes; The feed rate of propylene is 30 kilograms / hour; The feed rate of hydrogen is 0.4 gram / hour; The propylene molar ratio was 0.008.

[0120] 4) Test results

[0121] The continuous test was carried out for 48 hours according to the above conditions, and the operation of the device was stable. The polymer obtained by the reaction was analyzed and tested, and the results are listed in Table 1.

Embodiment 3

[0123] 1) raw material (with embodiment 1)

[0124] 2) test device (with embodiment 1)

[0125] 3) Test conditions

[0126] Step (1) pre-polymerization: reaction pressure is 2.5MPa, reaction temperature is 10°C, reaction time is 12 minutes; main catalyst, triethylaluminum, dicyclopentyldimethoxysilane DCPDMS (commonly known as D-Donor) feed Amounts are 1.1g / hour, 0.051mol / hour, 0.0082mol / hour respectively; Al / Si (mol / mol)=6.2; Propylene feed rate is 10 kg / hour

[0127] (2) Step gas phase polymerization: 98 DEG C of reaction temperature, reaction pressure is 2.3MPa, and reaction time is 60 minutes; The feed rate of propylene is 30 kilograms / hour; The feed rate of hydrogen is 0.6 gram / hour; The propylene molar ratio was 0.012.

[0128] 4) Test results

[0129] The continuous test was carried out for 48 hours according to the above conditions, and the operation of the device was stable. The polymer obtained by the reaction was analyzed and tested, and the results are listed i...

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Abstract

The invention relates to polypropylene with narrow distribution of molecular weight and a preparation method, and especially relates to a propylene polymer with narrow distribution of molecular weight by employing a Ziegler-Natta catalyst through direct reactor polymerization. The polymer has high and adjustable isotacticity, the molecular weight distribution is narrow, and the high-molecular trailing index is high. propylene is not contained in a locational isomeric structure, the melting point and crystallization temperature are high, compared with a traditional degradation method for producing the polypropylene with narrow distribution, the polypropylene with narrow distribution of molecular weight has the advantages of economy, energy saving and environmental protection. The product is especially suitable for the fields with high fluidity requirement such as spinning, injecting by a thin wall, casting the transparent material. In addition, due to characteristic of narrow distribution of molecular weight, the polymer has a certain advantage on transparency application aspect.

Description

technical field [0001] The invention relates to a polypropylene with a narrow molecular weight distribution and its preparation, in particular to a propylene polymer with a narrow molecular weight distribution directly prepared by polymerization in a reactor using a Ziegler-Natta catalyst. Background technique [0002] The molecular weight distribution width of polypropylene is an important structural parameter that directly affects the processing behavior of polypropylene and its physical and mechanical properties. Polypropylene with a narrow molecular weight distribution has a wider Newtonian plateau area during the flow process, and its viscosity changes less with shear rate fluctuations, and the extrusion volume is easier to control stably, especially suitable for molding that requires low viscosity and high fluidity method. For example, in spinning and other applications, it is necessary to control the molecular weight distribution of polypropylene to a narrow distribu...

Claims

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Application Information

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IPC IPC(8): C08F10/06C08F4/649C08F4/654
CPCC08L23/10C08F110/06C08F2410/06C08F2/34C08F4/6492C08F4/651C08F4/6548C08F2500/12C08F2500/15C08F2/001C08F4/16C08F4/46C08F10/06C08F210/16
Inventor 王良诗于鲁强张师军乔金樑郭梅芳杨芝超殷建军黄红红侯莉萍盛建昉
Owner CHINA PETROLEUM & CHEM CORP
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