CN1049981A

CN1049981A - The manufacturing of porous filtering film of diacetate cellulose

Info

Publication number: CN1049981A
Application number: CN 89107252
Authority: CN
Inventors: 李业琛
Original assignee: Guangzhou Institute of Chemistry of CAS
Current assignee: Guangzhou Chemical Co Ltd of CAS; Guangzhou Institute of Chemistry of CAS
Priority date: 1989-09-09
Filing date: 1989-09-09
Publication date: 1991-03-20
Anticipated expiration: 2004-09-09
Also published as: CN1022981C

Abstract

The present invention relates to a kind of manufacture method of porous filtering film of diacetate cellulose.

The used solvent of the present invention is acetone and industrial alcohol, additive is a magnesium chloride, the weight of each component of system film sol consists of: cellulose diacetate raw material 2.5-3.5, acetone 14-20, ethanol 8-12, magnesium chloride 2-3.5, film forming procedure room temperature and relative humidity be 100% with the saturated solvent vapour pressure under, to make film sol drawout in the plane, immerse temperature then and be the film forming of condensing in 5-28 ℃ the water, this method compared with prior art, system film cost is low, technology is simple, pollution-free, film properties is superior.

Description

The manufacturing of porous filtering film of diacetate cellulose

The present invention relates to a kind of manufacture method of porous filtering film of diacetate cellulose, it comprises preparation and these two steps of film forming procedure of making film sol.

The manufacturing of existing cellulose esters microporous barrier is to use the phase transformation method, utilize again at Chinese desalinization in 1984 and water and disclose a kind of method of making raw material manufacturing miillpore filter of Triafol T and cellulose diacetate mixing in association's free paper session data, be as solvent and add additive and form preparation liquid with dichloroethanes and absolute ethyl alcohol, film forming procedure is film liquid to be spread over make the whole evaporations of solvent do the processing of heating at last on the flat board.Disclose a kind of manufacture method that is used for the cellulose diacetate microporous barrier of artificial kidney at United States Patent (USP) U.S.3.883.626, do raw material with cellulose diacetate, with acetone and methyl alcohol as solvent and add CaCl ₂Form preparation liquid, film forming procedure is that preparation liquid is spread on the flat board, heats then solvent evaporation 10 minutes, immerses film forming in the methyl alcohol again.The performance of the cellulose acetate microporous barrier that above method is made is more expensive than nitrocellulose, and the solvent that above method need have certain toxicity with dichloroethanes or this class of methyl alcohol, film forming procedure need be through carrying out evaporation stage with solvent in gas phase, because these solvents are volatile, it is very difficult reclaiming these solvent vapours from gas phase, so the said method cost of making the cellulose acetate microporous barrier is than higher and environment also produced certain pollution.

The object of the invention be to overcome the prior art weak point and provide that a kind of manufacturing cost expense is low, technology is simple, the manufacture method of the pollution-free and porous filtering film of diacetate cellulose that film properties is superior.

The present invention can reach by following measure: form in the component of film making solution, used cellulose diacetate raw material can also use the cellulose diacetate silk leftover bits of cigarette filter tip to do raw material except can adopting conventional cellulose diacetate product, used solvent is acetone and industrial alcohol (90-95%), and used additive is Mgcl ₂6H ₂O, the preparation of film making solution is rapid in two steps, with acetone the cellulose diacetate raw material is all dissolved earlier, and then the ethanolic solution that adds magnesium chloride is made the system film sol, film forming procedure is to keep solvent and water saturation vapour pressure in closed system, make the system film sol sprawl into dissolved glue film, then dissolved glue film is immersed and condense into solid film in the water.

According to above measure, the each component weight of forming film making solution is: cellulose diacetate raw material 2.5-3.5, acetone 14-20, ethanol 8-12, Mgcl ₂6H ₂O 2-3.5

Film forming procedure is to carry out in room temperature (8-30 ℃), with scraper with colloidal sol with the speed uniform spreading of 1 meter of per minute on surface plate, be 100% in relative humidity, operation is after 0.5-2 minute in the atmosphere of saturated acetone and ethanol vapour pressure, dissolved glue film promptly immerses in the water.

Dissolved glue film immerses water, and the temperature of water is 5-28 ℃, and content of acetone is 0-15% in the water, and the setting time of dissolved glue film in water is 2-4 minute.

The superior performance of the porous filtering film of diacetate cellulose that the present invention makes is illustrated by following several respects:

(1) the cellulose mixed esters microporous barrier of the porous filtering film of diacetate cellulose of this method manufacturing and U.S. Millipore company and West Germany Sartorious company production compares with SEM, and the structure that proves the porous filtering film of diacetate cellulose of this method manufacturing is uniform.

(2) the every test parameter such as the following table of the porous filtering film of diacetate cellulose of this method manufacturing:

(water flux is in 0.5 kilograms per centimeter ²Pressure is measured down)

(3) at room temperature be dipped in the water of 100 times of its weight relatively 30 days with the porous filtering film of diacetate cellulose of this method manufacturing, analysis water-like proves that this film is released in the water without any trace materials.Illustrate that this film is reliable and stable in water.

(4) it is 150 centimetres with the porous filtering film of diacetate cellulose area ², filter 200 liters in Guangzhou running water after, the filtered water turbidity reduces to zero, with the impurity atomic spectroscopic analysis of cross section at face, following various element is arranged:

Element

Si

Fe

Mg

Mn

Pb

Al

Ti

Ca

Cu

Zn

Cr

Ni

Sn

Content (%)

＞1

0.01

0.03

＞1

0.01

0.03

0.3

0.003

0.01

0.003

This film has filtration result to there being the heavy metal element that is harmful to health in the running water.

The present invention compared with prior art has the following advantages:

(1) use the cellulose diacetate silk leftover bits of cigarette filter tip as system pleurodiaphragmatic in terspace material, its price has only 1/10th of regular cellulose diacetate cost of material, can make China cigarette factory above cigarette filter tip cellulose diacetate silk leftover bits of annual tens of tons obtain more valuable utilization, turn waste into wealth.

(2) with acetone ethanol as solvent, this is the minimum kind solvent of organic solvent poisoning, allowing limit at air is 1000ppm, prior art as solvent, has certain toxicity with dichloroethanes or methyl alcohol, allowing limit at air is 200ppm.

(3) film forming procedure is fairly simple, and colloidal sol does not need to carry out the heating evaporation solvent stage and flood into mem stage at methyl alcohol in gas phase through dissolved glue film after spreading over the plane, and this method directly immerses the film forming of condensing in the water with colloidal sol.

(4) acetone, ethanol and the magnesium chloride in the film forming procedure colloidal sol is all water-soluble, can use distillating method to recycle, and water can recycle, and film-forming process does not produce environmental pollution.

Embodiment one

In a container with cover, add cellulose diacetate acid cellulose silk leftover bits 250 grams of cigarette filter tip, add acetone 1400 grams again, stir, with the lid sealing, at room temperature make all dissolvings of silk, obtain a kind of white thickness colloidal sol, be called first liquid, in another container, add Mgcl ₂6H ₂O 200 grams add ethanol 800 grams again, stir and all dissolve until magnesium chloride granules, obtain a kind of clear solution, are called second liquid.Add second liquid in the first liquid and stir, solution is filtered by the above metallic sieve of 300 orders, filtrate is collected in carries out vacuum deaerator again in the bottle, promptly obtain making film sol, film forming procedure is at room temperature (8 ℃) knifing in closed system, it is 100% that closed system keeps relative humidity, saturated acetone and ethanol vapour pressure, the speed of colloidal sol with 1 meter of per minute is spread on the glass plate, promptly immerse in the water through glass plate after 2 minutes, water temperature is 5 ℃, through 4 minutes dissolved glue films film forming of condensing in water, with clear water film is embathed twice again, wet film is clipped in the cardboard moisture content in the film is blotted, and its content of acetone of water that dissolved glue film is condensed is lower than 15%.

Embodiment two

Add cellulose diacetate (394-30) 350 grams that Eastman company produces in a container with cover, ketone 2000 grams stir in adding again, with the lid sealing, particle is all dissolved, obtain a kind of translucent thickness colloidal sol, be called first liquid, in another container, add Mgcl ₂6H ₂O 350 grams, add ethanol (90%) 1200 gram again, stirring is all dissolved magnesium chloride granules, obtain a kind of clear solution, be called second liquid, add second liquid in the first liquid and stir, the solution filtration becomes the system film sol after handling with deaeration, film forming procedure is at room temperature (30 ℃) knifing in closed system, colloidal sol spreads on the glass plate, promptly immerses in the water through glass plate after 0.5 minute, and water temperature is 28 ℃, through 2 minutes dissolved glue films film forming of condensing in water, washing and wipe dry promptly obtain the porous filtering film of diacetate cellulose finished product again.

Claims

1, a kind of is the miillpore filter manufacture method of raw material with the cellulose diacetate, this method comprises with solvent and additive and forms the system film sol jointly and will make film sol and sprawl in the plane by solvent change and the film forming procedure that condenses, it is characterized in that solvent for use is acetone and ethanol, additive is a magnesium chloride, the preparation of system film sol in two steps, with acetone the plain raw material of two vinegar fibers is dissolved earlier, the ethanolic solution that adds magnesium chloride is then made the system film sol, film forming procedure carries out in closed system, to make film sol and sprawl into dissolved glue film, again colloidal sol will be dipped in the film forming of condensing in the water.

2,, it is characterized by (by weight) composed as follows of colloidal sol each component according to the system film sol described in the claim 1:

Cellulose diacetate raw material 2.5～3.5

Acetone 14～20

Ethanol 8～12

Magnesium chloride (Mgcl ₂6H ₂O) 2～3.5

3, according to the film-forming process described in the claim 1, it is characterized by etoh solvent can be industrial alcohol, concentration 90-95%.

4, according to the film-forming process described in the claim 1, the temperature that it is characterized by film-forming process is 8～30 ℃.

5, according to the film forming procedure of claim 1, it is characterized by with 1 meter/minute speed and colloidal sol sprawled in the plane with scraper, relative humidity be 100% and saturated acetone and ethanol vapour pressure under immerse in the water after moving 0.5～2 minute.

6, according to the film forming procedure described in the claim 5, the water logging condition, the temperature that it is characterized by water is 5～28 ℃, in the water in the content of ketone be 0～15%, condense in water time of film forming of dissolved glue film is 2～4 minutes.

7, according to the film-forming process described in the claim 1, it is characterized by the used cellulose diacetate raw material of system film can be the cellulose diacetate silk leftover bits that cigarette filter tip is used.