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Preparation method for high heat resistance polyvinylidene fluoride

A technology of polyvinylidene fluoride and vinylidene fluoride is applied in the field of preparation of high heat-resistant polyvinylidene fluoride, which can solve the problems of PVDF molecular weight distribution, high production cost, poor thermal stability, etc.

Active Publication Date: 2012-02-01
ZHEJIANG FLUORINE CHEM NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The advantage of this method is that the polymerization is carried out at a higher temperature (75-130°C), and the polymerization speed is faster; the disadvantage is that the emulsifier is expensive, and the emulsion needs post-treatment processes such as coagulation, washing, dehydration, and drying, and the production cost is high. , and the prepared PVDF has a wide molecular weight distribution and poor thermal stability

Method used

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  • Preparation method for high heat resistance polyvinylidene fluoride

Examples

Experimental program
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Effect test

Embodiment 1

[0039] In a closed polymerization reactor with a capacity of 20L, nitrogen is purged to remove oxygen, so that the oxygen content in the reactor is lower than 50ppm. Add 12Kg deionized water, 3.9g magnesium hydroxide, 1.8g diisopropyl peroxydicarbonate, 50g diethyl malonate, 2.5Kg vinylidene fluoride, raise the temperature to 47°C, turn on the stirring paddle at a speed of 700r / After keeping for 1 hour, slowly add 4.5Kg of vinylidene fluoride to keep the pressure at about 5.6MPa, and at the same time add 15g of diethyl malonate in 3 times at intervals of 40min. After the addition was completed, the insulation polymerization was continued for 2.5 hours, and then the reaction was terminated. Wash the polyvinylidene fluoride slurry with deionized water until the foam disappears, and the conductivity of the washing solution drops below 1 μs / cm, and then vacuum-dry it at 90° C. for 15 hours to obtain a finished product.

Embodiment 2

[0041] In a closed polymerization reactor with a capacity of 20L, nitrogen is purged to remove oxygen, so that the oxygen content in the reactor is lower than 50ppm. Add 12Kg of deionized water, 9.2g of magnesium hydroxide, 145g of diisopropyl peroxydicarbonate, 100g of diethyl malonate, 3.5Kg of vinylidene fluoride, heat up to 60°C, and turn on the stirring paddle at a speed of 500r / min After keeping for 1.5 hours, slowly add 3.8Kg of vinylidene fluoride to keep the pressure at about 6.6MPa, and at the same time add 15g of diethyl malonate in 3 times at intervals of 40min. After the addition was completed, the insulation polymerization was continued for 1.5 hours, and then the reaction was terminated. Wash the polyvinylidene fluoride slurry with deionized water until the foam disappears, and the conductivity of the washing solution drops below 1 μs / cm, and then vacuum-dry it at 96° C. for 18 hours to obtain a finished product.

Embodiment 3

[0043] In a closed polymerization reactor with a capacity of 20L, nitrogen is purged to remove oxygen, so that the oxygen content in the reactor is lower than 50ppm. Add 12Kg deionized water, 10.5g magnesium hydroxide, 60g diisopropyl peroxydicarbonate, 30g diethyl malonate, 3.2Kg vinylidene fluoride, heat up to 66°C, turn on the stirring paddle, and the speed is 620r / min After keeping for 1.1 hours, slowly add 4Kg of vinylidene fluoride to keep the pressure at about 5.6MPa, and at the same time add 10g of diethyl malonate in 3 times at intervals of 40min. After the addition was completed, the insulation polymerization was continued for 2 hours, and then the reaction was terminated. Wash the polyvinylidene fluoride slurry with deionized water until the foam disappears, and the conductivity of the washing solution drops below 1 μs / cm, and then vacuum-dry it at 100° C. for 20 hours to obtain a finished product.

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Abstract

Provided is a preparation method for high heat resistance polyvinylidene fluoride, which belongs to the technical field of fluorochemical industry. The method is characterized by comprising the following steps: 1) blowing nitrogen into an enclosed polymerization kettle to remove oxygen and adding deionized water, magnesium hydroxide, diisopropyl peroxydicarbonate, diethyl malonate and vinylidene fluoride; 2) under the conditions that reaction pressure is 3.0 to 7.0 MPa and reaction temperature is 45 to 120 DEG C, starting a stirring paddle, with a rotating speed being 350 to 750 r / min, and allowing an obtained mixture to react for 4 to 6 hours so as to prepare a polyvinylidene fluoride slurry; 3) rinsing the polyvinylidene fluoride slurry with deionized water until foams disappear, allowing the conductivity of rinsing liquid to decrease to less than 1 mu s / cm, and carrying out vacuum drying at a temperature of 90 to 100 DEG C for 15 to 20 hours so as to prepare a finished product. According to the invention, suspension polymerization is employed in the preparation method; a finally prepared polyvinylidene fluoride resin is loose and has greatly reduced possibility of adhering to the kettle and excellent high temperature resistance

Description

technical field [0001] The invention belongs to the technical field of fluorine chemical industry, in particular to a preparation method of high heat-resistant polyvinylidene fluoride. Background technique [0002] Polyvinylidene fluoride (PVDF) refers to a homopolymer of vinylidene fluoride (VDF) or a copolymer of vinylidene fluoride (VDF) and a small amount of other fluorine-containing vinyl monomers. It is a high molecular weight, semi-crystalline, High toughness thermoplastic engineering plastics. Usually, the relative molecular mass of PVDF is 400,000 to 600,000, the fluorine content is 59%, the crystallinity is 60% to 80%, and its repeating unit is (-CH 2 -CF 2 -) n Alternate arrangement of groups. Because the fluorine atom has the strongest electronegativity (-4.0), the C-F bond becomes the chemical bond with the largest bond energy in the covalent single bond (485KJ / mol). In addition, the fluorine atom has a lower polarizability and a smaller van der Gas radius ...

Claims

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Application Information

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IPC IPC(8): C08F114/22C08F2/18C08F2/38C08F4/34
Inventor 苗国祥王姓传李晓育陈炜
Owner ZHEJIANG FLUORINE CHEM NEW MATERIAL
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