Method for preparing semihomogeneous cation exchange membrane

A cation-exchange membrane and cation-exchange technology, applied in semi-permeable membrane separation, chemical instruments and methods, membrane technology, etc., can solve the problems of difficult stability of ion-exchange membrane performance, hard texture of ion-exchange membrane products, poor thermal stability, etc. Achieve the effect of improving cost performance and technical competitiveness, better thermal stability, and reducing film surface resistance

Active Publication Date: 2017-03-22
HANGZHOU IONTECH ENVIRONMENTAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In fact, on the one hand, polyvinyl chloride is prone to degradation during thermal processing, and its thermal stability is far inferior to that of polyethylene and non-thermoplastic cross-linkable ion-exchange resin powder, and the performance of the obtained ion-exchange membrane is difficult to stabilize.
On the other hand, polyvinyl chloride-based ionic membrane products are hard and easily damaged during use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Raw material preparation:

[0026](1) Preparation of thermoplastic polyethylene-sulfonated polystyrene-based cation-exchange composite resin powder: Weigh 300 kg of low-density polyethylene powder (LDPE, Yanshan Petrochemical, brand: 1I20A, melt index: 20g / 10min, pulverize to 20-50 mesh), put it into a 2000-liter polymerization reactor, then add 1000 liters of tap water and 2.0 kg of polyvinyl alcohol, and stir to raise the temperature to 60-65°C. Add a polymerized oil phase consisting of 182 kg of styrene, 18 kg of divinylbenzene (mass purity 80%) and 2.0 kg of benzoyl peroxide, heat up and polymerize after absorbing for 1 hour, polymerize at 75°C for 2 hours, and polymerize at 90°C overnight , Washed with water, filtered and dried to obtain about 497 kg of white powder. Weigh 120 kg of the above-mentioned white powder, put it into a 1000 liter sulfonation reaction kettle, add 240 liters of dichloroethane, swell at room temperature for 2 hours and then drain to remove...

Embodiment 2

[0032] Raw material preparation: replace the LLDPE granules in Example 1 (Mitsui Chemicals, brand: 20100J, melt index: 8.0g / 10min) with LDPE granules (Yanshan Petrochemical, brand: 1I20A, melt index: 20g / 10min), and the rest Materials and preparations were carried out as described in Example 1.

[0033] Semi-homogeneous membrane manufacturing: Weigh 20 kg non-thermoplastic crosslinked sulfonated polystyrene cation exchange resin powder, 12 kg thermoplastic polyethylene-sulfonated polystyrene based cation exchange composite resin powder, 10 kg polyethylene Powder (LDPE, grade: 1I20A), 2.5 kg of polyisobutylene powder, directly put into the internal mixer, pre-mixed for 10 minutes. Afterwards, steps such as internal mixer mixing, two-roller mill discharge, four-roller calendering, cooling, automatic cut-off, and net-covering hot pressing are carried out according to the method described in Example 1, and the obtained semi-homogeneous membrane cation The size of the exchange mem...

Embodiment 3

[0035] Preparation of raw materials: prepare the LLDPE particles in Example 1 (Mitsui Chemicals, brand: 20100J, melt index: 8.0g / 10min) and the LDPE particles in Example 2 (Yanshan Petrochemical, brand: 1I20A, melt index: 20g / 10min) 10min), all the other raw materials and preparation process are carried out as described in Example 1.

[0036] Semi-homogeneous membrane manufacturing: Weigh 20 kg of non-thermoplastic cross-linked sulfonated polystyrene cation exchange resin powder, 9 kg of thermoplastic polyethylene-sulfonated polystyrene-based cation exchange composite resin powder, and 5 kg of LLDPE powder (brand: 20100J), 5 kg of LDPE powder (brand: 1I20A), and 1.4 kg of polyisobutylene powder are directly put into the internal mixer and pre-mixed for 6 minutes. Afterwards, steps such as internal mixer mixing, two-roller mill discharge, four-roller calendering, cooling, automatic cut-off, and net-covering hot pressing are carried out according to the method described in Examp...

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Abstract

The invention discloses a method for preparing a semihomogeneous cation exchange membrane, and the method comprises the following steps: step 1), thermoplastic polyethylene-sulfonated polystyrene based cation exchange composite resin powder, non-thermoplastic cross-linked sulfonated polystyrene cation exchange resin powder, polyethylene powder and polyisobutylene powder are mixed evenly; step 2), a prefabricated membrane is obtained by successively melting blending in an internal mixer, discharging slices with a two-roller open mill, continuously rolling with a four-roller machine, cooling with a cold roll machine and cutting with a cutting machine; and step 3), the upper surface and the lower surface of the prefabricated membrane are covered with reinforced mesh cloth, and the semihomogeneous cation exchange membrane is obtained by pressing with a hot press. Sulfonic acid groups with cation exchange effect in the semihomogeneous cation exchange membrane prepared by the method are connected mutually without interruption, so that membrane surface resistance is greatly reduced. All kinds of membrane-forming materials are well compatible and tightly bonded, selective transmission of the membrane is higher, and the comprehensive performance is better than that of a heterogeneous cation exchange membrane in the prior art.

Description

technical field [0001] The invention belongs to the technical field of functional polymer film production, and in particular relates to a production method of a semi-homogeneous cation exchange membrane with polyethylene and sulfonated cross-linked polystyrene as substrates. Background technique [0002] Electrodialysis technology with ion exchange membrane as the core component is more and more widely used. According to different membrane structures, ion exchange membranes can be divided into heterogeneous membranes, semi-homogeneous membranes and homogeneous membranes. Among them, the homogeneous ion-exchange membrane has excellent performance, but its manufacturing process is complex and technically difficult, so its production and promotion are limited. However, heterogeneous ion exchange membranes are easy to produce, and although their overall performance is not good, they are still more commonly produced and applied in my country. Heterogeneous ion exchange membrane...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/28B01D71/26B01D61/46B01D67/00C08L25/06C08L23/06C08L23/20
Inventor 卿波莫剑雄
Owner HANGZHOU IONTECH ENVIRONMENTAL TECH
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