CN1063675C

CN1063675C - Composite porous filtering film material and its prodn

Info

Publication number: CN1063675C
Application number: CN95112042A
Authority: CN
Inventors: 康勇; 罗茜
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-10-09
Filing date: 1995-10-09
Publication date: 2001-03-28
Anticipated expiration: 2015-10-09
Also published as: CN1147417A

Abstract

The present invention discloses a composite porous filtering film material and a producing method thereof. The composite porous filtering film material uses plain weave plain-weave or cross-weave polypropylene filament yarn woven close as base cloth on which a coating agent is uniformly coated, the base cloth is then scratched by a film making cutter and is immersed in a solution proportionally compounded by dimethylformamide and water for pore formation, and then the base cloth is cleaned in distilled water after being soaked and is finally dried in an infrared drying oven. The composite porous filtering film material has the characteristics of small pore space, uniform hole distribution, low filtrate turbidity when filtering, long service life of filter cloth, high cake unloading rate, strong functionality, etc., and can be widely used for solid and liquid two-phase filtration and separation.

Description

Microporous membrane composite filter media material and manufacture method thereof

The invention belongs to the Separation of Solid and Liquid material, particularly a kind of microporous membrane composite filter media.

At present, the filter medium that China matches with filter plant mainly is divided into three major types: (1) woven cloth (2) is the fibrage of compacting at random, as nonwoven (3) hard material, and as micropore ceramics, sintered metal net etc.And that the third material is used is very limited, and what have is in conceptual phase.The scope that preceding two media is used is wider, and as vacuum filter, air pressure filtration machine, mechanism filter-pressing machine and filter centrifugal can be used, and in use, mainly have following problem.

1, the hole of filter cloth is too big, and is bigger at the initial stage flow velocity that filters, but after filtering a period of time, solid particle will enter in the hole of medium, and filter efficiency is greatly reduced, and need just can keep production through clear water flushing commonly used.

2, the filtrate turbidity is too big.If with filter is to reclaim solid particle, so the filtrate turbidity too conference cause solid particle to run off, cause unnecessary economic loss.If with filter plant is reclaiming clean waste water, the filtrate turbidity too greatly then can not get satisfactory water, influences industrial subsequent job and causes serious environmental to pollute.

3, the filter cloth life-span is short.Filter cloth is in use because of easily blocked, and in very short time, porosity greatly reduces, though can the water flushing regenerate, the ability of regeneration is very low.Just need in general 8-30 days to change once, cause very big economic loss.

4, discharge rate is low.No matter be woven cloth or nonwoven, the surface is all rough and uneven in surface, and tiny fiber is arranged, and causes filter cake fully not lay down, and influences the production efficiency of filter.

5, present woven cloth and nonwoven can't reclaim fine solid particle, we can say that also reclaiming this part material has very big difficulty, and fine at present so that ultra-fine material Separation of Solid and Liquid problem almost has in every field, this is that the conventional filtration medium cann't be solved.

In view of the deficiency that prior art exists, it is little and be evenly distributed to the purpose of this invention is to provide a kind of hole, and the filtrate turbidity is low, and the filter cloth life-span is long, discharge rate is high, functional strong microporous membrane composite filter media material and manufacture method thereof.

The present invention is achieved by the following technical solutions in order to achieve the above object.

This material selection plain weave or twill POLYPROPYLENE FILAMENT FILTRATION FABRIC are the microporous membrane that forms coated with coating agent on the base cloth surface.

Method of manufacturing technology step: at first select base cloth, adopt hydrophobicity plain weave or twill POLYPROPYLENE FILAMENT FILTRATION FABRIC preferably, be fixed on the glass plate, be distributed to the coating agent for preparing on the base cloth equably again, then with system hymenotome blade coating, the filter cloth after the coating is immersed dimethyl formamide and water in proportion, dimethyl formamide: water is 5: 3-1: in 4 the solution, soaked 12-15 minute, soaking temperature is 10 ℃-70 ℃.Form the composite of microporous membrane, the filter cloth after soaking is put into the distillation tank clean, the dimethyl formamide in the filter cloth thoroughly is dissolved in the water, scavenging period is 2-10 minute.Filter cloth after will cleaning at last is at the infrared drying oven inner drying, and temperature is 25 ℃-50 ℃, and be 5-40 minute drying time, promptly can be made into microporous membrane composite filter media material.

The polyurethane of coating agent prescription for being dissolved by dimethyl formamide, concentration 10%-30%, institute's doping has the dimethyl formamide solution of inclined to one side fluorine ethylene, concentration 20% and polytetrafluoroethylene superfine powder.Proportioning is a polyurethane: vinylidene is 1: 4-2: 3, and polyurethane: polytetrafluoroethylene (PTFE) is 2: 3-3: 2.

The present invention compared with prior art has following advantage:

1, hole is little and be evenly distributed.Owing to this medium be on the conventional woven cloth coating after pore-forming is handled obtains.When filtering with this medium, what mainly carry out is both surface filtration, and particle can't enter the inside of medium, thereby filter efficiency can not reduce because of the prolongation of filtration time.

2, the filtrate turbidity is low.Owing to the present invention has coated the microporous membrane filtration medium that one deck organic composite material forms on the filter medium of routine, solid particle nearly all during filtration all can't pass through, thereby the turbidity of filtrate is minimum.

3, the filter cloth life-span is long.Filter is under normal duty, and filter medium of the present invention is little because of hole, and is blocked hardly, thereby service life is longer, unless be subjected to the cutting of sharp implements, impact to wait and damages filter cloth.Coating and base cloth are bonding closely and have higher chemical inertness, can not peel off with base cloth or be corroded by other material.

4, discharge rate height.The one side of microporous membrane composite filter media coating is smooth smooth, and film contains the extremely strong fluorine material of lubricating ability, filter cake bonding lower on film, thereby discharge rate height, thus can greatly improve the disposal ability of filter.

5, functional strong.The hydrophily of filter medium film of the present invention can artificially be controlled, in the Separation of Solid and Liquid field, make it have certain hydrophily, base cloth then is the higher fibers material of hydrophobicity, film surface is coated with water membrane all the time in air pressure or vacuum filtration, has permeable and air-locked function, as the hydrophilic ceramic filter medium of the micropore of present exploitation, can reduce filter gas consumption amount greatly like this, reach purpose of energy saving.Base cloth is selected hydrophobic fibers material, the resistance in the time of can reducing moisture content and flow through base cloth, thus guarantee to obtain under the less pressure reduction the higher rate of filtration.

Table one, different filtering medium property contrasts

Below provide embodiments of the invention.

Embodiment 1:

At first select base cloth, select the plain weave POLYPROPYLENE FILAMENT FILTRATION FABRIC for use and be fixed on the glass plate, again the coating agent for preparing is evenly distributed on the base cloth, the coating agent prescription is the polyurethane of dimethyl formamide dissolving, concentration is 10%, add the vinylidene dimethyl formamide solution, concentration is 20%, polyurethane: vinylidene 1: 4, and polyurethane: polytetrafluoroethylene (PTFE) is 1: 1, then with system hymenotome blade coating, filter cloth after the coating is immersed in the solution that dimethyl formamide and water prepares in proportion at 5: 3, soaked 12 minutes, soaking temperature is 25 ℃, filter cloth after soaking is put into distilled water, and scavenging period is 2 minutes.Filter cloth after will cleaning at last is at the infrared drying oven inner drying, and temperature is 25 ℃, 5 minutes drying times.

Embodiment 2:

At first select the twill POLYPROPYLENE FILAMENT FILTRATION FABRIC to make base cloth, and be fixed on the glass plate, be distributed to the coating agent for preparing on the base cloth equably again, the coating agent prescription is the polyurethane of dimethylformamide dissolving, concentration is 30%, the dimethyl formamide solution that adds additive superfine powder of polytetrafluoroethylene and vinylidene, polyurethane: Kynoar is 1: 3, polyurethane: polytetrafluoroethylene (PTFE) is 3: 2, strike off with the system hymenotome then, filter cloth after the coating is immersed in the solution that dimethyl formamide and water prepares in proportion at 1: 4, soaked 15 minutes.Soaking temperature is 70 ℃, the filter cloth after soaking is put into distilled water clean, and scavenging period is 10 minutes, and the filter cloth after will cleaning at last is at the infrared drying oven inner drying, and temperature is 50 ℃, and be 40 minutes drying time.

Claims

1, a kind of microporous membrane composite filter media material, this material selection plain weave or the woven cloth of twill polypropylene filament yarn are base cloth, the microporous membrane that forms coated with coating agent on the surface, it is characterized in that the coating agent prescription can be the polyurethane of dimethyl formamide dissolving, concentration is 10%～30%, the adding additive has the dimethyl formamide solution concentration 20% of vinylidene, and superfine powder of polytetrafluoroethylene, polyurethane wherein: vinylidene is 1: 4～2: 3, polyurethane: polytetrafluoroethylene (PTFE) is 2: 3～3: 2.

2, the described a kind of microporous membrane composite filter media preparation methods of claim 1, it is characterized in that: at first select base cloth, adopt plain weave or twill POLYPROPYLENE FILAMENT FILTRATION FABRIC, and be fixed on the glass plate, be distributed to the coating agent for preparing on the base cloth equably again, use molding cutter blade coating then, filter cloth after the coating is immersed dimethyl formamide and water dimethyl formamide in proportion: water is in 5: 3～1: 4 the solution, soaked 12～15 minutes, soaking temperature is 10～70 ℃, form the composite of microporous membrane, the filter cloth after soaking is put into the distillation tank clean, make the dimethyl formamide in the filter cloth thoroughly be dissolved in the water, scavenging period is 2～10 minutes, filter cloth after will cleaning at last is at the infrared drying oven inner drying, and temperature is 25～50 ℃, and be 5～40 minutes drying time.