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Adjustment method for molecular weight distribution of rare-earth isoprene rubber

A technology of molecular mass distribution and adjustment method, which is applied in the field of molecular mass distribution adjustment of rare earth isoprene rubber, can solve the problems of unreported synthesis processing performance, pollution of recovered solvent, and increased burden of solvent recovery unit of production equipment, etc.

Inactive Publication Date: 2012-05-23
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with natural rubber, its disadvantages are: adhesion, vulcanization time, tensile strength and tear strength of vulcanized rubber (especially high temperature tear resistance), incision growth, wear resistance and fatigue life, etc. are not as good as natural rubber. rubber
Its catalytic system uses neodymium carboxylate, alkylaluminum and chloride to obtain isoprene rubber with narrow molecular weight distribution, but it is prepared in the laboratory, and there is no report on the synthesis and processability of isoprene rubber with wide molecular weight distribution. rubber
[0006] The above technologies still belong to the laboratory technology, and have not yet reflected the pilot test and industrial test technology, and all have the problem of low cis-1,4 structure content (infrared analysis is about 95-96%)
In addition, most of them use BHT as a terminator and antioxidant, and the relative molecular mass (220) of BHT is small, which is easy to sublimate and volatilize, pollute and recycle the solvent, which not only increases the burden on the solvent recovery unit of the production device, but also affects the polymerization reaction. In the post-treatment drying process, BHT volatilizes a lot and pollutes the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The polymerization device adopts a continuous polymerization device, and the volume of the polymerization tank is 20L. It is a continuous polymerization device with 3 polymerization tanks, and is equipped with a glue tank, a termination tank and a post-processing device (including coagulation, post-processing recovery, extrusion drying, etc.). The feed rate of isoprene was 3.0 L / h, and the feed rate of solvent hexane was 17 L / h. After mixing isoprene and hexane, the temperature reaches 20°C through the preheater, and enters the first polymerization tank at the same time as the rare earth catalyst. The feed amount of rare earth catalyst is:

[0024] Neodymium naphthenate hexane solution: 0.31mol / L, 1.92mmol / h, 6.20ml / h;

[0025] Hexane solution of triethylaluminum: 3.96mol / L, 48.0mmol / h, 12.12ml / h;

[0026] Hexane solution of diisobutyl aluminum chloride: 0.6mol / L, 11.16mmol / h, 18.6ml / h.

[0027] The catalyst neodymium naphthenate and triethylaluminum were mixed by a ...

Embodiment 2

[0029] With embodiment 1, in the catalytic system, neodecanoate replaces neodymium naphthenate, and the feeding amount of rare earth catalyst and operating condition are the same as embodiment 2, and anti-aging agent is changed into 2246, measures the ratio of rare earth isoprene rubber product every two hours. Mooney, molecular mass and its distribution, selected representative samples to measure the cis 1, 4 structure of the product. The cis 1,4 structure content measured by infrared spectrum is 97.0%, the molecular mass distribution curve measured by GPC is a single peak, the number average molecular mass is 610000-840000, and the molecular mass distribution Mw / Mn=1.9-2.8. Mooney viscosity is 82-85 (ML 1+4 100℃ ).

Embodiment 3

[0031] Same as Example 1, in the catalytic system, diethylaluminum hydride replaces triethylaluminum, the feed amount and operating conditions of the rare earth catalyst are the same as in Example 1, the anti-aging agent is changed to 4020, and the rare earth isoprene rubber product is measured every two hours Mooney, molecular mass and its distribution, select representative samples to measure the cis 1,4 structure of the product. The cis 1,4 structure content measured by infrared spectroscopy is 96.8%, and the molecular mass distribution curve measured by GPC is a double peak,

[0032] The number average molecular mass is 720000-812000, and the molecular mass distribution Mw / Mn=1.9-2.3. Mooney viscosity is 79-82 (ML 1+4 100℃ ).

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Abstract

The invention relates to an adjustment method for the molecular weight distribution of a rare-earth isoprene rubber; an isoprene monomer comprises 5-20g / 100mL of hexane in concentration; a ratio of the mole number of Nd of a rare-earth catalyst to the gram of the isoprene monomer is 1*10<-7>-1*10<-6>:1, wherein the rare-earth catalyst contains a component A, i.e. neodymium naphthenate or neodymium neodecanoic acid, a component B, i.e. one or a mixture of diethyl aluminium hydride and aluminium ethyl and a component C, i.e. one of aluminium diisobutyl monochloride or aluminium diethyl monochloride; the molar ratio of A to B to C is 1:5-20:1-5; different polymer molecular weight distribution indexes MW / MN in the range of 1.90-7.80 are obtained by respectively selecting feeding modes of (A+B)+C, (A+C)+B or (C+B)+A; and according to the adjustment method, the content of a cis-1,4 structure is larger than 96.5%, and the Moony viscosity is 80+ / -5 (ML+4100 DEG C).

Description

Technical field: [0001] The invention relates to a method for adjusting molecular mass distribution of rare earth isoprene rubber. Background technique: [0002] Isoprene rubber is also known as synthetic natural rubber, because its molecular structure and properties are the closest to natural rubber, it can replace natural rubber for tires and tire products, foam rubber, hoses, gaskets, medical gloves and other uses. Rare earth isoprene rubber has both the high molecular weight of lithium-based isoprene rubber, the high-cis structure of titanium-based isoprene rubber, and the same sequence configuration as natural rubber. It is structurally closest to natural rubber and is a rubber worthy of attention. Variety. However, compared with natural rubber, synthetic isoprene rubber is characterized by better extrusion and calendering properties, excellent in-mold fluidity, low hysteresis and controllable molecular weight. Compared with natural rubber, its disadvantages are: adhe...

Claims

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Application Information

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IPC IPC(8): C08F136/08C08F4/52C08F2/01
Inventor 白晨曦孙艳红叶青吴乃文赵彦强陈丽娟丛柏玉刘晓华王硕王勋章张学全王佛松
Owner PETROCHINA CO LTD
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