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A method for recycling polyvinylidene fluoride hollow fiber membrane waste silk

A polyvinylidene fluoride and fiber membrane technology, applied in the field of polymer material recycling, can solve the problem that the pretreatment process is not elaborated, and achieve the effects of avoiding adverse effects, reducing production costs, and reducing environmental pollution

Active Publication Date: 2017-07-07
ZHEJIANG DONGYANG ENVIRONMENTAL ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the patent does not elaborate on the most important pretreatment process in the recycling process of polyvinylidene fluoride waste

Method used

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  • A method for recycling polyvinylidene fluoride hollow fiber membrane waste silk

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] like figure 1 As shown, waste silk pretreatment: cleaning the waste silk produced in the manufacturing process;

[0037] Cleaning of silk waste generated during the manufacturing process includes first soaking with 1500ppm 35°C sodium hypochlorite for 12 hours, then washing with water at 30°C for 2 hours, and then drying at 60°C for 8 hours until the moisture content of waste silk is ≤1.5%;

[0038] Dissolving and gel curing: Mix the cleaned waste silk with dimethylformamide in a mass ratio of 1:0.8 and dissolve at 70°C, then centrifugally filter at 150 mesh and enter 50°C pure water for gel solidification;

[0039] Drying: Dry the obtained cured gel at 60°C for 12 hours to a moisture content of ≤0.5%;

[0040] crush;

[0041] Granulation: Extrude and granulate at 180°C to obtain recycled polyvinylidene fluoride pellets with a diameter of 0.5-2mm and a length of 0.5-2.5mm.

[0042] Then the polyvinylidene fluoride hollow fiber membrane is prepared by using the recycl...

Embodiment 2

[0052] like figure 1 As shown, waste silk pretreatment: cleaning the waste silk produced in the manufacturing process;

[0053] Cleaning of silk waste generated during the manufacturing process includes first soaking in 2500ppm 45°C sodium hypochlorite for 24 hours, then washing at 50°C for 4 hours, and then drying at 95°C for 4 hours until the moisture content of waste silk is ≤1.5%;

[0054] Dissolution and gel solidification: Mix the cleaned waste silk with dimethylformamide according to the mass ratio of 1: 1.2 and dissolve at 80°C, then centrifugally filter at 250 mesh and enter 70°C pure water for gel solidification;

[0055] Drying: Dry the obtained cured gel at 95°C for 6 hours to a moisture content of ≤0.5%;

[0056] crush;

[0057] Granulation: Extrude and granulate at 200°C to obtain recycled polyvinylidene fluoride granules with a diameter of 0.5-2mm and a length of 0.5-2.5mm.

[0058] Then the polyvinylidene fluoride hollow fiber membrane is prepared by using t...

Embodiment 3

[0068] The cleaning of the waste silk generated during the manufacturing process includes first soaking in 2000ppm 40°C sodium hypochlorite for 20 hours, then washing at 40°C for 3 hours, and then drying at 85°C for 6 hours until the moisture content of the waste silk is ≤1.5%. The waste silk and dimethylformamide are mixed according to the mass ratio of 1:1 and dissolved at 75°C, and then centrifuged and solidified in water after gelation.

[0069] Then the cleaned waste silk and dimethylformamide are mixed according to the mass ratio of 1:1.1 and dissolved at 75°C, then centrifugally filtered at 200 mesh, and then entered into pure water at 60°C for gel solidification;

[0070] Drying: Dry the obtained cured gel at 75°C for 8 hours to a moisture content of ≤0.5%;

[0071] crush;

[0072] Granulation: Extrude and granulate at 190°C to obtain recycled polyvinylidene fluoride pellets with a diameter of 0.5-2mm and a length of 0.5-2.5mm.

[0073] Then the polyvinylidene fluori...

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Abstract

The invention belongs to the field of recycling and reuse of high polymer materials, and in particular relates to a waste polyvinylidene fluoride hollow fiber membrane filament recycling method which comprises the following waste filament pretreatment steps in sequence: washing, namely, washing waste filaments generated in the manufacturing process, including soaking for 12-24 hours by using 1500-2500ppm sodium hypochlorite at 35-45 DEG C, washing for 2-4 hours by using water at 30-50 DEG C, and subsequently drying for 4-8 hours at 60-95 DEG C till the water content of the waste filaments is less than or equal to 1.5%; washing waste filaments replaced from sewage plants, namely, rinsing with clean water, and subsequently pickling for 12-24 hours, wherein 0.15-0.35wt% or 1-2wt% of citric acid is used as acid for pickling; soaking for 12-24 hours by using a mixed liquid of 1500-2500ppm sodium hypochlorite and 0.05-0.15wt% of sodium hydroxide at 35-45 DEG C, further washing for 2-4 hours at 30-50 DEG C, and drying for 4-8 hours at 60-95 DEG C till the water content of the waste filaments is less than or equal to 1.5%; dissolving and curing by using gel; drying, crushing and pelleting. By adopting the method, a polyvinylidene fluoride raw material can be effectively washed, recycled and reused, and the environment pollution caused by waste membranes is avoided.

Description

technical field [0001] The invention belongs to the field of recycling of polymer materials, and in particular relates to a method for recycling polyvinylidene fluoride hollow fiber membrane waste silk. Background technique [0002] With the development of membrane technology, hollow fiber separation membranes have been increasingly widely used in the fields of separation of gas and liquid mixtures. In order to improve the service life of hollow fiber membranes, the membrane materials are generally selected from polymer materials with good chemical stability and weather resistance, which are not corroded by acids, alkalis, strong oxidants or halogens at room temperature, and can be exposed outdoors for a long time without aging Phenomenon, so it also brings difficulties to the treatment of waste film silk produced by a large number of applications. [0003] Polyvinylidene fluoride (PVDF) is a semi-crystalline polymer. The crystalline region endows the film with good thermal...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J11/08C08L27/16B01D71/34B01D69/08
CPCY02W30/62
Inventor 周钱华沈海军叶婷婷
Owner ZHEJIANG DONGYANG ENVIRONMENTAL ENG