Preparation of high melt strength polypropylene

A high-melt-strength, polypropylene technology is applied in the field of high-melt-strength polypropylene preparation, which can solve the problems of large equipment investment, high technical requirements, and high odor, and achieves low equipment investment, simple process and low cost. Effect

Active Publication Date: 2009-03-04
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Improving the melt strength of polypropylene through polymerization is still only in the research and exploration stage
[0004] In the early 1990s, Himont Corporation (CN86100791A, CN1105033A, EP190889) used low-temperature vacuum or nitrogen to irradiate polypropylene to generate free radicals, then heat up grafting, and finally high-temperature inactivation, successfully obtained long-chain branched polypropylene, and It has been commercially applied, but the method requires high technical requirements and requires a large investment in equipment
However, thiuram additives have a strong smell, and the grafting efficiency of polypropylene needs to be further improved

Method used

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  • Preparation of high melt strength polypropylene
  • Preparation of high melt strength polypropylene
  • Preparation of high melt strength polypropylene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Example 1 50 g of polypropylene (homopolypropylene powder, melt index: 7.2 g / 10 min) and 0.1 g of antioxidant B215 were pre-mixed. 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane was dissolved in acetone according to the amount of 3.8mmol / kg polypropylene, and trimethylolpropane triacrylate was dissolved according to 44mmol / kg polypropylene The amount of propylene is dissolved in acetone, after the dissolution is complete, the acetone solution is evenly sprayed on the pre-mixed polypropylene powder, put in a vacuum oven at 40°C for 12 hours, and the vacuum degree is 10 -6 MPa, and then put it into the material chamber of the internal mixer, the temperature is set as: 175 °C in the first zone, 180 °C in the second zone, 180 °C in the third zone, the speed is 60 rpm, and the material is discharged after 7 minutes of reaction when the torque is stable. Some samples were taken for performance testing and melt strength determination. The results are shown in Table 1.

Embodiment 2

[0044] Example 2 50g polypropylene (homopolypropylene powder, melt index is 7.2g / 10min), 0.1g antioxidant B215 and copper dimethyl dithiocarbamate are premixed, dimethyl dithiocarbamate The amount of copper formate is 1.84mmol / kg polypropylene. 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane was dissolved in acetone according to the amount of 3.8mmol / kg polypropylene, and trimethylolpropane triacrylate was dissolved according to 44mmol / kg polypropylene The amount of propylene is dissolved in acetone, after the dissolution is complete, the acetone solution is evenly sprayed on the pre-mixed polypropylene powder, put in a vacuum oven at 40°C for 12 hours, and the vacuum degree is 10 -6 MPa, and then put it into the material chamber of the internal mixer, the temperature is set as: 175 °C in the first zone, 180 °C in the second zone, 180 °C in the third zone, the speed is 60 rpm, and the material is discharged after 7 minutes of reaction when the torque is stable. Some samples were...

Embodiment 3

[0045] Example 3 500 g of polypropylene (homopolypropylene powder, with a melt index of 7.2 g / 10 min) and 1 g of antioxidant B215 were premixed. 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane was dissolved in acetone according to the dosage of 3.4mmol / kg polypropylene, and trimethylolpropane triacrylate was dissolved according to 20mmol / kg polypropylene The amount of propylene is dissolved in acetone, after the dissolution is complete, the acetone solution is evenly sprayed on the pre-mixed polypropylene powder, put in a vacuum oven at 40°C for 12 hours, and the vacuum degree is 10 -6 MPa, and then put it into a twin-screw extruder with L / D=40 and Φ of 24mm. The speed of the extruder is set at 100 rpm. The extruder is divided into eight heating zones, respectively: 185°C , 210°C, 220°C, 220°C, 220°C, 220°C, 220°C, 230°C, extrusion granulation. Some samples were taken for performance testing and melt strength determination. The results are shown in Table 1.

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Abstract

The invention discloses a method for preparing polypropylene with high melt strength, which comprises melt-blending polypropylene, monomer containing double bond, peroxide, dithiocarbamate series substance and antioxidant. The dithiocarbamate is added as adjuvant to inhibit the propylene degradation of the peroxide, improve the graft ratio, reduce monomer amount containing double bond, and save the cost. The obtained polypropylene with high melt strength has melt strength more than 2-15 times of that of raw material, and gel content smaller than 10%.

Description

technical field [0001] The invention relates to a method for preparing high melt strength polypropylene. Background technique [0002] As a thermoplastic polymer material with excellent performance, polypropylene (PP) has the characteristics of low density, non-toxicity, easy processing and molding, and excellent product comprehensive performance. It is widely used in automobiles, household appliances, electronics, packaging and building materials. , has become the fastest growing variety of general resins. Although PP has many advantages, due to the inherent characteristics of propylene coordination polymerization, propylene polymerization with Ziegler-Natta catalyst and metallocene catalyst mostly obtains linear structure PP, and linear PP has low melt strength in molten state. When stretching, the melt cannot show the strain hardening effect, which directly causes some defects of PP during melt processing, including edge curling and shrinkage during high-speed extrusion ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F255/02C08F2/38
Inventor 唐涛张振江邱健姜治伟
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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