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Preparation method of heat-resistant polyethylene, heat-resistant polyethylene prepared therefrom, and composition thereof

A technology of heat-resistant polyethylene and its composition, which is applied in the field of heat-resistant polyethylene and its composition, and can solve the problem of narrow molecular weight distribution of polyethylene, unsuitability for industrial applications, poor balance between production cost and high temperature creep resistance of products Performance and other issues

Active Publication Date: 2022-07-05
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] The main purpose of the present invention is to provide a preparation method of heat-resistant polyethylene, the heat-resistant polyethylene prepared therefrom and its composition, so as to solve the complex preparation process, cumbersome operation and unsuitability for industrial application in the prior art, Polyethylene has narrow molecular weight distribution, relatively poor processability and high cost of metallocene catalysts, and the problem of not being able to balance the relationship between production cost and product high temperature creep resistance

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  • Preparation method of heat-resistant polyethylene, heat-resistant polyethylene prepared therefrom, and composition thereof

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preparation example Construction

[0023] As described in the background art section, the existing methods for preparing heat-resistant polyethylene cannot effectively solve the problems of complex preparation process, complicated operation and unsuitable for industrial application. In order to solve the above problems, the present invention provides a method for preparing heat-resistant polyethylene, which includes the following steps: (a) conducting a first polymerization reaction of ethylene, hydrogen and a catalyst in the presence of a first solvent to form a first polymerization reaction. a polymerization solution; (b) adding ethylene, hydrogen, 1-butene and 1-hexene to the first polymerization solution to carry out a second polymerization reaction to form a second polymerization solution; and (c) in the second polymerization solution In the liquid, ethylene, hydrogen, 1-butene and 1-hexene are further added to carry out the third polymerization reaction to obtain this heat-resistant polyethylene, wherein t...

Embodiment 1

[0040] In the presence of n-hexane, a Ziegler-Natta catalyst (made of titanium tetrachloride-triethylaluminum [TiCl 4 -Al(C 2 H 5 ) 3 ] formed catalyst), ethylene and hydrogen were added to the first reactor, the ethylene addition accounted for 60% of the total addition (36t / h), the reactor temperature was 75°C, the reaction pressure was 0.8MPa, the hydrogen ethylene partial pressure The ratio was 4.0 and the reaction time was 2.5h. Subsequently, the slurry was discharged into the second reaction kettle. In the second reaction kettle, the added amount of ethylene accounted for 25% of the total added amount (36t / h). For 0.3, 1-butene and 1-hexene were added in an amount of 5% by weight of ethylene in three reactors, wherein the mass ratio of 1-butene and 1-hexene was 9:1, and the reaction time was 2h. Subsequently, the slurry was discharged into the third reaction kettle. In the third reaction kettle, the added amount of ethylene accounted for 15% of the total added amount ...

Embodiment 2

[0043] In the presence of n-hexane, a Ziegler-Natta catalyst (made of titanium tetrachloride-triethylaluminum [TiCl 4 -Al(C 2 H 5 ) 3 ] formed catalyst), ethylene and hydrogen were added to the first reactor, the ethylene addition accounted for 45% of the total addition (36t / h), the reactor temperature was 80°C, the reaction pressure was 0.9MPa, and the hydrogen ethylene partial pressure The ratio was 3.5, and the reaction time was 2h. Subsequently, the slurry was discharged into the second reaction kettle. In the second reaction kettle, the added amount of ethylene accounted for 30% of the total added amount (36t / h). For 0.4, 1-butene and 1-hexene were added in an amount of 8% by weight of ethylene in three reactors, wherein the mass ratio of 1-butene and 1-hexene was 8:2, and the reaction time was 2.4h. Subsequently, the slurry was discharged into the third reaction kettle. In the third reaction kettle, the added amount of ethylene accounted for 25% of the total added am...

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Abstract

The present invention provides a preparation method of heat-resistant polyethylene, heat-resistant polyethylene prepared therefrom and a composition thereof. The preparation method comprises: (a) carrying out a first polymerization reaction of ethylene, hydrogen and a catalyst in the presence of a first solvent to form a first polymerization solution; (b) adding ethylene, hydrogen, 1-butylene to the first polymerization solution (c) further adding ethylene, hydrogen, 1-butene and 1-hexene in the second polymerization solution to carry out the third polymerization reaction, Heat-resistant polyethylene is obtained, wherein the partial pressure ratio of hydrogen to ethylene in step (a) is 3 to 4:1; the partial pressure ratio of hydrogen to ethylene in step (b) is 0.2 to 0.5:1; step ( The partial pressure ratio of hydrogen to ethylene in c) is 0.02-0.1:1. The method is simple in process, easy to operate and suitable for industrial application, and the prepared heat-resistant polyethylene and its composition have improved processability.

Description

technical field [0001] The invention relates to the field of polymer materials, in particular, to a method for preparing heat-resistant polyethylene, a heat-resistant polyethylene prepared therefrom, and a composition thereof. Background technique [0002] Heat-resistant polyethylene (Polyethylene of raised temperature resistance, PE-RT for short) is a non-cross-linked polyethylene that can be used in hot and cold water pipes. Moderate control makes it have good flexibility and processing performance, and has good hydrostatic resistance under high temperature conditions. PE-RT pipes are mainly used for domestic hot and cold water delivery pipes, including floor heating, heating connections, heat exchangers, solar panels and thermal circulation systems. [0003] In the initial stage of PE-RT pipe development, there were only pipes copolymerized with ethylene and octene. With the continuous progress of catalyst technology and polymerization technology, PE-RT polymerization t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F210/16C08F210/08C08F210/14C08F2/34C08L23/08C08L27/12C08K5/00
CPCC08F210/16C08L23/0815C08F210/08C08F210/14C08F2/34C08L27/12C08K5/00
Inventor 李连鹏王硕陈光岩杨俊峰宋尚德张桂荣李晓东石宝珠
Owner PETROCHINA CO LTD