A kind of manufacturing method of injection molding grade high-density polyethylene

A high-density polyethylene and manufacturing method technology, applied in the production of bulk chemicals, etc., can solve the problems of low melt flow rate and inability to meet the injection fluidity requirements of long runners for large injection molded parts, and achieve high rigidity melt flow properties, good formability and processability, and the effect of high melt fluidity

Active Publication Date: 2016-06-29
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, there are many domestic manufacturers of injection-grade high-density polyethylene special materials, but the melt flow rate is mostly below 10g / 10min, such as HDPE5306J of Yangzi, HDPE2100J of Yanshan and Daqing, and HDPE1300J has been produced on Mitsui process equipment. The melt flow rate is only 14g / 10min. Due to the low melt flow rate of the material, the above products cannot meet the injection fluidity requirements of large injection molded parts with long runners and thin-walled injection molded parts.

Method used

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  • A kind of manufacturing method of injection molding grade high-density polyethylene
  • A kind of manufacturing method of injection molding grade high-density polyethylene
  • A kind of manufacturing method of injection molding grade high-density polyethylene

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Experimental program
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Embodiment 1

[0031] According to the high-flow injection-grade high-density polyethylene special material involved in the present invention and its manufacturing method, on the high-density polyethylene process device of Mitsui Chemicals, the parallel A polymerization process of double slurry polymerization tanks is adopted, and the high-efficiency Ziegler-Natta catalyst (three Titanium chloride and alkylaluminum), under the conditions of operating temperature 78-86°C and pressure 0.20-0.80MPa, ethylene, hydrogen, propylene and solvent hexane are simultaneously added to the first and second reactors for copolymerization reaction, reaction 4 Hours, the resulting polymer is a high density low molecular weight polyethylene copolymer. After the polyethylene slurry produced by polymerization is separated and dried, it is granulated by adding a special additive formula for high-flow injection-grade high-density polyethylene special materials. The specific production process control parameters of...

Embodiment 2

[0039] According to the present invention, the addition of ethylene, hydrogen and propylene is specially designed to achieve the required properties of the product. The amount of hydrogen added is well controlled, so that the molecular weight of the polymer produced by the reaction of the two polymerization tanks is small, so that the melt flow rate of the final product is within a relatively high required range, and the polymer has good processing and molding properties. The added amount of comonomer propylene is well controlled, so that the density of the polymer produced by the two polymerization tanks is relatively high, so that the density of the final product is within a relatively high required range, and the purpose of high rigidity of the polymer is achieved.

Embodiment 2

[0040] In Example 2, by changing the process control parameters in Example 1, especially increasing the hydrogen / ethylene ratio (mol%), a high-density polyethylene special material with a higher melt flow rate can be obtained. The specific production process control parameters of the two reactors are shown in Table 5.

[0041] The production process parameter of table 5 embodiment two

[0042]

[0043] Compared with the high-density polyethylene obtained in Example 1, due to the control of the hydrogen / ethylene ratio (mol%), the hydrogen / ethylene ratio (mol%) of the two kettles was increased in Example 2, as 3.0, and the hydrogen / ethylene ratio (mol%) of two kettles in embodiment one is 1.0, so the melt flow rate of the product obtained in this embodiment is higher, and the melt flow rate of the product obtained in embodiment one is lower.

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Abstract

The invention discloses a preparation method for an injection molding grade high density polyethylene, and belongs to the field of special material preparation method of high density polyethylene. Reaction conditions are as following: using a Mitsui Chemicals high density polyethylene process unit, taking titanium trichloride and aluminum alkyl as catalysts, ethylene as a raw material, propylene as a comonomer, and hexane as a diluent; performing polymerization reaction in a polymerizing pot, at a temperature of 78 to 86 DEG C and under a pressure of 0.20 to 0.80 MPa; and ethylene flow quantity is 2 to 5 t / h, mole ratio of hydrogen / ethylene is 1.0 to 3.0m, and propylene flow quantity is 20 to 120 kg / h. The injection molding grade high density polyethylene of the invention possesses higher flow rate, small injection pressure, high rigidity, high surface glossiness, and long oxidation induction time. Processing and modeling are easy, distortion is difficult to happen, injection modeling is complete, weld-line strength is high, and defective index is low.

Description

Technical field: [0001] The invention relates to a method for manufacturing a high-density polyethylene special material, in particular to a method for manufacturing a high-flow injection-grade high-density polyethylene special material. Background technique: [0002] Injection molded products have the most complex shape and the largest variety among all plastic molded products. Bulk injection molding products include turnover boxes, plastic pallets, industrial barrels, trash cans, toys, etc. Generally, resins are required to have good fluidity, good resistance to environmental stress cracking and low temperature resistance. The consumption of HDPE injection molding products is strong in the market, but the competition is also fierce. Low cost is always the goal pursued by manufacturers, and the cost of plastic raw materials usually accounts for a large proportion of product cost, accounting for about 50-80%. Thin walls can help reduce this proportion, so The design require...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F210/16C08F4/64
CPCY02P20/52
Inventor 陆小义阚林钱建忠徐振明游忠林傅勇陈明华柏基业朱宇飞鲍光复季宝云姜志荣
Owner CHINA PETROLEUM & CHEM CORP
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