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Hollow porous membrane and process for producing the same

A technology for porous membranes and manufacturing methods, applied in chemical instruments and methods, membranes, membrane technologies, etc., can solve the problems of reduced separation characteristics, problems in production costs, and the inability of two layers to be fully integrated, so as to reduce costs, mechanical Excellent strength

Active Publication Date: 2011-04-27
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in order to form a dense layer at two parts of this porous membrane, a second film-forming process is required, so the two layers may not be completely integrated. In this case, gaps are generated between the layers, and the outer layer may be easily separated. Delamination, or the possibility that the damaged part and the defective part of each layer are connected through the gap, resulting in a decrease in separation characteristics
In addition, in order to maintain the water permeability, the two layers cannot be completely integrated, and there is a problem in terms of both water permeability and peel resistance.
In addition, as a method of improving the peeling resistance of the support body and the porous membrane layer, a method of impregnating the main part of the braid with a film-forming liquid with a low polymer concentration has been adopted, but this method is different from the porous film that bears the peeling resistance. The bonding part on the support side of the porous layer is only a fine porous part that enters between the fibers of the braid, and this porous part is formed by using a low concentration of polymer in order to maintain the permeability, although it was found that the peeling resistance was improved. improved, but its strength is still problematic
In addition, in addition to the production and coating process of the dilute film-forming stock solution, a secondary film-forming process is required, so the production process is long, and there is a problem in terms of production cost.

Method used

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  • Hollow porous membrane and process for producing the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0251] (manufacture of support)

[0252] use Figure 6 The shown support body manufacturing apparatus 20 manufactures the support body 10 which consists of the hollow knitted string 12. As shown in FIG.

[0253] As the yarn, polyester fiber (denier: 84 dtex, number of filaments: 36) was used. As the bobbin 22, five bobbins wound with 5 kg of the above-mentioned polyester fiber were prepared. As the circular knitting machine 24 , a desktop circular knitting machine (manufactured by Yuanjing Textile Machinery Co., Ltd., number of latch needles: 12, needle size: 16 gauge, and spindle diameter: 8 mm) was used. As the rope supply device 26 and the recovery device 30, Nelson rollers are used. As the heating die 28 , a stainless steel die (inner diameter D: 5 mm, inner diameter d: 2.2 mm, length: 300 mm) having a heating device was used.

[0254] The polyester fibers drawn from the five bobbins 22 are gathered into one as the yarn 16 (the total fineness is 420dtex), and then circ...

Embodiment 2

[0280] (Manufacture of hollow porous membrane)

[0281] The hollow porous membrane 1 was produced in the same manner as in Example 1 except that only the membrane-forming stock solution (1) was applied to the outer peripheral surface of the support 10 in the first annular nozzle 42 .

[0282] The obtained hollow porous membrane 1 has an outer diameter of about 2.78 mm, an inner diameter of about 1.2 mm, an average thickness of the porous membrane layer 11 of about 340 μm, a bubble point of 110 kPa, and a water permeability of 115 m 3 / m 2 / h / MPa.

[0283] The porous hollow fiber membrane was subjected to a peeling resistance test. As a result, the entire second layer of the porous hollow fiber membrane was peeled off from the first layer and remained on the kraft tape. Partially carried out the same test, the entire first layer part was not peeled off from the support, and only a part of the first layer part epidermis remained on the kraft tape.

[0284] The hollow porous m...

Embodiment 3

[0286] In addition to Yarn 16, use polyester fiber A (denier: 84dtex, number of filaments: 72) and polyester fiber B (high tenacity polyester fiber, fineness: 235dtex, number of filaments: 24), and prepare one bobbin 22 A bobbin A wound with 5 kg of polyester fiber A and two bobbins B wound with 5 kg of polyester fiber B (the total fineness is 554 dtex), as the circular knitting machine 24, a desktop circular knitting machine (Circular Well Manufactured by Textile Machinery Co., Ltd., number of latch needles: 10, needle size: 16 gauge, and spindle circumference diameter: 10 mm), the support body 10 was produced in the same manner as in Example 1, up to the polyester fiber A without the bobbin A.

[0287] The obtained support 10 had an outer diameter of about 2.1 mm and an inner diameter of about 1.2 mm. The number of loops 17 of the hollow knitted rope 12 constituting the support 10 is 10 per turn, and the maximum opening width of the mesh 18 is about 0.15 mm. The length of t...

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Abstract

A hollow porous membrane reduced in cost and excellent in separating properties, water permeability, and mechanical strength; and a process for producing, at low cost, the hollow porous membrane including a porous membrane layer having excellent adhesion to a support. The hollow porous membrane has a porous membrane layer having dense layers around the outer surface thereof and around the inner surface thereof, respectively. The process for producing the hollow porous membrane comprises continuously applying film-forming dopes, i.e., a first film-forming dope and a second film-forming dope, each comprising a material for the porous membrane layer and a solvent to the peripheral surface of a hollow support with annular nozzles to form superposed layers of the dopes and solidifying these film-forming dopes simultaneously. In the process for producing a hollow porous membrane by applying film-forming dopes comprising a material for the porous membrane layer and a solvent to the peripheral surface of a hollow support and solidifying the dopes to form a porous membrane layer, a hollow knitted cord formed from one multifilament yarn by circular knitting is used as the support.

Description

technical field [0001] The present invention relates to a hollow porous membrane suitable for water treatment as a precision filtration membrane or an ultrafiltration membrane and a method for producing the same. [0002] This application claims priority based on Japanese Patent Application No. 2008-133504 for which it applied to Japan on May 21, 2008, and uses the content here. Background technique [0003] In recent years, water treatment by a membrane method using a filtration membrane excellent in separation completeness and compactness has attracted attention due to increased emphasis on environmental pollution and strengthening of regulations. In such water treatment applications, filtration membranes are required to have excellent separation properties and water permeability, as well as high mechanical strength. [0004] Currently, filter membranes produced by wet or dry-wet spinning methods such as polysulfone, polyacrylonitrile, cellulose acetate, and polyvinyliden...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D69/08B01D69/10
CPCB01D2325/02B01D61/14B01D2325/40B01D69/08B01D69/087B01D69/02B01D2325/04B01D2323/60B01D2325/02833B01D69/1071B01D67/0088B01D2325/0283B01D2325/0232
Inventor 寺町正史村濑圭隅敏则广本泰夫藤木浩之仓科正树皆川正和
Owner MITSUBISHI CHEM CORP
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