Polyetheylene moulding compound suitable as a pipe material with excellent processing properties

A molding compound and ethylene technology, applied in the direction of rigid pipe, pipe, thin material processing, etc., can solve problems such as low melt strength, inability to achieve thickness accuracy, and sagging

Inactive Publication Date: 2004-01-07
BASELL POLYOLEFINE GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, lower melt strength often makes the extrusion process persistently unstable
Moreover, when this molding compound is processed and extruded into thick-walled pipes, it will cause sag problems
The problem is that a certain thickness accuracy cannot be achieved in industrial production, because the solidification time from the thermoplastic state to the tube takes up to several hours, during which time the wall thickness of the tube around the tube is not uniform due to the own weight of the melt

Method used

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  • Polyetheylene moulding compound suitable as a pipe material with excellent processing properties

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-9

[0031] The first dual mode ethylene polymer (A) is prepared according to the specifications of WO91 / 18934, adopting the Ziegler catalyst whose composition is a made in the operation step 2.2 in Example 2, the preparation operating conditions of the polymer (A) are listed in Table 1 below.

[0032] Reactor I

[0033] The melt flow index MFI of the prepared ethylene polymer (A) 5 / 190℃ A 0.49 dg / min, density d A It was 0.948 g / cc and the comonomer content was 1.5% by weight (based on the total weight of higher molecular weight components).

[0034] Then according to EP-B-0003129 instructions, prepare the second double mode ethylene polymer (B), for this reason, under 85 ℃ of constant temperature conditions, in the presence of the Ziegler catalyst described in EP-B embodiment 1, by stirring, in 6.7 kg of ethylene / h and 0.24 kg of 1-butene / h were introduced into the diesel with a boiling range of 130-170° C. placed in the reaction tank within 6 hours. After the reac...

Embodiment 10-12

[0044] In order to determine the homogeneity of the mixture (no spots), the following three molding compounds were prepared:

Embodiment 1

[0045] Example 10 is the molding compound of Example 1, ie pure polymer (A).

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Abstract

The invention relates to a polymeric molding compound made from a first ethylene polymer (A) and from a second ethylene polymer (B) which is particularly suitable for producing thick-walled large-caliber pipes, wherein the molding compound comprises an amount in the range from 55 to 75% by weight of the first ethylene polymer (A) and an amount in the range from 25 to 45% by weight of the second ethylene polymer (B), based in each case on the total weight of the molding compound, where the first ethylene polymer (A) is a copolymer of ethylene with a 1-olefin having a total number of carbon atoms in the range from 4 to 10 as comonomer, and with a proportion of from 0.2 to 5% by weight of comonomer, based on the weight of the first ethylene polymer (A), and with a wide bimodal molar mass distribution, and where the second ethylene polymer (B) is a copolymer made from ethylene units and from a 1-olefin having a number of carbon atoms in the range from 4 to 10, which has a bimodal molar mass distribution differing from that of the first ethylene polymer (A). The invention further relates to a high-strength pipe made from this molding compound, and to its use for the transport of gas or water.

Description

technical field [0001] The present invention relates to polymer molding compounds produced from a first ethylene polymer (A) and a second ethylene polymer (B). The processing performance of the molding compound makes it especially suitable for the manufacture of thick-walled and large-diameter pipes. Background technique [0002] Polyethylene has been widely used in the manufacture of pipes, for example for gas conveying systems or water conveying systems, since such pipes require materials with high mechanical strength, high corrosion resistance and long-term durability. There is a great deal of literature describing such materials with a wide variety of properties and methods of making them. [0003] EP-A-603935 already describes molding compounds with a bimodal molar mass distribution based on polyethylene, which are especially suitable for the manufacture of pipes. However, pipes made of the molding compound proposed in this document are poor in internal pressure long-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/20C08L23/04C08L23/08
CPCC08L2205/025Y10S138/07C08L23/0815C08L2205/02Y10T428/139C08L2666/04C08L23/08F16L9/12
Inventor P·克鲁姆派尔J·-F·恩德鲁
Owner BASELL POLYOLEFINE GMBH
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