CA1079225A - Bonding of fibers for diaphragms in electrolytic cells - Google Patents
Bonding of fibers for diaphragms in electrolytic cellsInfo
- Publication number
- CA1079225A CA1079225A CA244,699A CA244699A CA1079225A CA 1079225 A CA1079225 A CA 1079225A CA 244699 A CA244699 A CA 244699A CA 1079225 A CA1079225 A CA 1079225A
- Authority
- CA
- Canada
- Prior art keywords
- diaphragm
- fibers
- agent
- cementing agent
- slurry
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B13/00—Diaphragms; Spacing elements
- C25B13/04—Diaphragms; Spacing elements characterised by the material
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
The invention is concerned with a diaphragm for an electrolytic celle, which comprises a body of fibers cemented one to another by a cementing agent consisting of a heat-fusible hydrophobic material and containing a wetting agent to counteract the hydrophobic character of the heat-fusible hydrophobic material, a wetting agent also being present in the fiber material when the latter, in the absence of a wetting agent, is hydrophobic in nature; the wetting agent consists of a perfluorinated organic material or an inorganic material other than asbestos. The diaphragm of the invention is particularly useful in a chlor-alkali cell for brine electro-lysis.
The invention is concerned with a diaphragm for an electrolytic celle, which comprises a body of fibers cemented one to another by a cementing agent consisting of a heat-fusible hydrophobic material and containing a wetting agent to counteract the hydrophobic character of the heat-fusible hydrophobic material, a wetting agent also being present in the fiber material when the latter, in the absence of a wetting agent, is hydrophobic in nature; the wetting agent consists of a perfluorinated organic material or an inorganic material other than asbestos. The diaphragm of the invention is particularly useful in a chlor-alkali cell for brine electro-lysis.
Description
--` 10792ZS
The invention relates to diaphragms for electrolytic cells.
In copending Canadian application No. 244,710, filed on January 29, 1976, there is disclosed an electrolytic cell assembly comprising an anode, a cathode and a diaphragm there-between, wherein the diaphragm comprises discrete fibers of a self-bGnding thermoplastic material, the fibers having a diameter of from 0.05 to 40 microns, preferably from 0.05 to 10 microns.
As is known to those skilled in the art, conventionally asbestos is employed as the diaphragm material. Asbestos has many advantages as a diaphragm material. These advantages have been reported and detailed a plurality of times. Yet, there exists a plurality of disadvantages attendant the use of asbestos diaphragms, such as swelling of the diaphragm.
Although the invention of the copending application provides more than adequate substitutive materials for asbestos, there still exists a need for improving asbestos diaphragms. ~ -Contemporaneously, it would be advantageous to improve the fiber diaphragms of the copending application. -According to the invention, there is provided a diaphragm for an electrolytic cell, which diaphragm comprises a body of fibers cemented one to another by a cementing agent consisting of a heat-fusible hydrophobic material and containing a hereinafter-defined wetting agent to counteract the hydro-phobic character of said heat-fusible hydrophobic material, a wetting agent also being present in the fiber material when the latter, in the absence of a wetting agent, is hydrophobic in nature.
The cementing agent preferably is a fluorohydrocarbon or contains a fluorohydrocarbon.
The fibers of the diaphragm may be made of thermo~-`
plastic or thermosetting resin or may be made of an inorganic fibrous material. Examples of fibrous materials are, inter alia, polyolefins, polycarbonates, polyesters and polyamides, specific examples being polyethylene, polypropylene, hexamethylene adip-amide and other nylons, polyethylene terephthalate, poly - 4 -methylpentene -1, polyltetramethylene) terephthalate, poly-styrene - polyvinylidene chloride copolymers, chlorinated polyvinyl chloride, polycarbonates of 2 - (4 - hydroxymethyl) propane (Bisphenol A) and polyphenylene oxide.
Preferably, the diaphragm material is asbestos, The fiber material may be a mixture of two or more different materials.
Because of the hydrophobic nature of the thermoplastic fibers, which is true also for at least part of the surfaces of the fiber body when made of other fibers, upon cementation, it is necessary to include within the internal structure or matrix of the fibers, per se, a hydrophilic material to ensure the wetting ability of the diaphragm. The term "wetting agent"
used herein means a perfluorinated organic material or an inorganic material other than asbestos e.g., are the inorganic materials specified below: -mica, titanates, such as barium titanate and potassiumtitanate, talc, vermiculite, titanium dioxide, boron nitride, kaolinite, diatomaceous earth and clays, as well as mixtures thereof.
Preferred wetting agents are the perfluorinated fatty acids, alcohols or sulfonate-based surfactants.
Although any heat-fusible cementing agent that is capable of resisting chemical attack in an electrolytic cell can be utilized, the fluorohydrocarbons have been found to be eminently useful. Usually, the cementing agents are utilized where the diaphragm material is non-fluorinated, or where the
The invention relates to diaphragms for electrolytic cells.
In copending Canadian application No. 244,710, filed on January 29, 1976, there is disclosed an electrolytic cell assembly comprising an anode, a cathode and a diaphragm there-between, wherein the diaphragm comprises discrete fibers of a self-bGnding thermoplastic material, the fibers having a diameter of from 0.05 to 40 microns, preferably from 0.05 to 10 microns.
As is known to those skilled in the art, conventionally asbestos is employed as the diaphragm material. Asbestos has many advantages as a diaphragm material. These advantages have been reported and detailed a plurality of times. Yet, there exists a plurality of disadvantages attendant the use of asbestos diaphragms, such as swelling of the diaphragm.
Although the invention of the copending application provides more than adequate substitutive materials for asbestos, there still exists a need for improving asbestos diaphragms. ~ -Contemporaneously, it would be advantageous to improve the fiber diaphragms of the copending application. -According to the invention, there is provided a diaphragm for an electrolytic cell, which diaphragm comprises a body of fibers cemented one to another by a cementing agent consisting of a heat-fusible hydrophobic material and containing a hereinafter-defined wetting agent to counteract the hydro-phobic character of said heat-fusible hydrophobic material, a wetting agent also being present in the fiber material when the latter, in the absence of a wetting agent, is hydrophobic in nature.
The cementing agent preferably is a fluorohydrocarbon or contains a fluorohydrocarbon.
The fibers of the diaphragm may be made of thermo~-`
plastic or thermosetting resin or may be made of an inorganic fibrous material. Examples of fibrous materials are, inter alia, polyolefins, polycarbonates, polyesters and polyamides, specific examples being polyethylene, polypropylene, hexamethylene adip-amide and other nylons, polyethylene terephthalate, poly - 4 -methylpentene -1, polyltetramethylene) terephthalate, poly-styrene - polyvinylidene chloride copolymers, chlorinated polyvinyl chloride, polycarbonates of 2 - (4 - hydroxymethyl) propane (Bisphenol A) and polyphenylene oxide.
Preferably, the diaphragm material is asbestos, The fiber material may be a mixture of two or more different materials.
Because of the hydrophobic nature of the thermoplastic fibers, which is true also for at least part of the surfaces of the fiber body when made of other fibers, upon cementation, it is necessary to include within the internal structure or matrix of the fibers, per se, a hydrophilic material to ensure the wetting ability of the diaphragm. The term "wetting agent"
used herein means a perfluorinated organic material or an inorganic material other than asbestos e.g., are the inorganic materials specified below: -mica, titanates, such as barium titanate and potassiumtitanate, talc, vermiculite, titanium dioxide, boron nitride, kaolinite, diatomaceous earth and clays, as well as mixtures thereof.
Preferred wetting agents are the perfluorinated fatty acids, alcohols or sulfonate-based surfactants.
Although any heat-fusible cementing agent that is capable of resisting chemical attack in an electrolytic cell can be utilized, the fluorohydrocarbons have been found to be eminently useful. Usually, the cementing agents are utilized where the diaphragm material is non-fluorinated, or where the
- 2 -,.~!~
-`` 1079ZZS
fibers,per se, are not self-bonding, but the use of these agents is applicable with all fibers. The cementing agent is in -general employed in an amount ranging from ten to thirty per-cent, by weight thereof, based on the weight of the fiber.
Preferably, the cementing is employed in an amount ranging from fifteen to twenty-five percent, by weight thereof, based ~-on the weight of the fiber.
The cementing agent may be employed as a dry powder or as a solution thereof in a non-reactive solvent. When`employed as a powder, the agent can conveniently be admixed with a fiber slurry from which to deposit, for example on a cathode screen, the fibers. Where deployed as a solution, one useful method ~;
, for applying the cementing agent is achieved by first depositing the fiber slurry on a cathode screen and thereafter, contacting the deposited fibrous diaphragm with the solution of the cement-ing agent.
Afrer the cementing agent has been applied, the diaphragm is then heat treated, conveniently at a temperature ranging from 100C to 400C for a period of from one-half to one hour, to fuse the cementing agent and so effect cementation of the fibers. The temperature and duration of treatment, of ( course, vary with the selected fiber used for the diaphragm ; and with the cementing agent.
Useful fluorohydrocarbon cementing agents contemplated for use in the present invention include, for example, fluori-nated ethylene propylene, polyethylene tetrafluoroethylene, polyethylene chlorotrifl~loLoethylerle, polychlorotrifluoro-ethylene and polyvinylidene fluoride, as well as mixtures ~; thereof.
Suitable solvents for deploying the fluorohydrocarbon as a solution include nitrobenzene and hexachlorobenzene.
Generally, a one to ten percent, by weight, solution is utilized.
~ 3 ~
~' .
.
'',"'"' , ' ' ' "' ' ' ---`` 1079ZZ5 In practising the present invention, it is preferred that where used, the thermoplastic fibers have a fiber diameter of from 0.05 to forty microns.
The following Examples are intended to illustrate the invention. In the Examples, all parts are by weight.
EXAMPLE I
To a conventional two percent asbestos slurry contain-ing 0.5% , (based on the weight of the asbestos) of Fluorad FC-126 fluorohydrocarbon surfactant ("Fluorad" is a Registered Trade Mark), was added twenty percent (based on the weight of the asbestos) of polyethylene chlorotrifluoroethylene powder.
The powder was mixed with the slurry to render the slurry uniform.
The slurry was then deposited onto a cathode screen by vacuum deposition substantially as described in Example I
of our copending Application No. 244,710.
The diaphragm was then dried in an oven at 100C
for eight hours. Thereafter, the diaphragm was heat treated to bond the asbestos fibers to each other as well as to the cathode, at 260C for one hour.
~ ~ .
The diaphragm was then mounted in a test chlor -alkali cell and brine electrolysis was carried out therewithin.
The cell having the diaphragm mounted therewithin produced 130 grams per liter of caustic at 95~ current efficiency.
EXAMPLE II
This Example illustrates the use of a cementing agent with a self-bonding fiber.
Following the procedure of Example I of Application No. 244,710, a polyethylene chlorotrifluoroethylene fiber slurry containing the same surfactant as defined therein was deposited on a cathode screen. After deposition, the fiber-screen assembly was dried in a vacuum oven at 100C. for a ,; ,,,r~ ., ' , .
`
10792,Z~
period of about eight hours. The dried fibers were then impregnated with a one percent solution of polyethylene chloro-trifluoroethylene in nitrobenzene at 70C as a cementing agent.
This was achieved by immersing the assembly within the solution. -Thereafter, the impregnated fiber-screen assembly was heated at 250C for about one-half hour to bond the fibers.
The cathode was then deployed in a brine electrolysis test cell. The cell produced a caustic concentration of 130 grams per liter with a 90% current efficiency.
' :i :
.
h~ .' 5 . ,'
-`` 1079ZZS
fibers,per se, are not self-bonding, but the use of these agents is applicable with all fibers. The cementing agent is in -general employed in an amount ranging from ten to thirty per-cent, by weight thereof, based on the weight of the fiber.
Preferably, the cementing is employed in an amount ranging from fifteen to twenty-five percent, by weight thereof, based ~-on the weight of the fiber.
The cementing agent may be employed as a dry powder or as a solution thereof in a non-reactive solvent. When`employed as a powder, the agent can conveniently be admixed with a fiber slurry from which to deposit, for example on a cathode screen, the fibers. Where deployed as a solution, one useful method ~;
, for applying the cementing agent is achieved by first depositing the fiber slurry on a cathode screen and thereafter, contacting the deposited fibrous diaphragm with the solution of the cement-ing agent.
Afrer the cementing agent has been applied, the diaphragm is then heat treated, conveniently at a temperature ranging from 100C to 400C for a period of from one-half to one hour, to fuse the cementing agent and so effect cementation of the fibers. The temperature and duration of treatment, of ( course, vary with the selected fiber used for the diaphragm ; and with the cementing agent.
Useful fluorohydrocarbon cementing agents contemplated for use in the present invention include, for example, fluori-nated ethylene propylene, polyethylene tetrafluoroethylene, polyethylene chlorotrifl~loLoethylerle, polychlorotrifluoro-ethylene and polyvinylidene fluoride, as well as mixtures ~; thereof.
Suitable solvents for deploying the fluorohydrocarbon as a solution include nitrobenzene and hexachlorobenzene.
Generally, a one to ten percent, by weight, solution is utilized.
~ 3 ~
~' .
.
'',"'"' , ' ' ' "' ' ' ---`` 1079ZZ5 In practising the present invention, it is preferred that where used, the thermoplastic fibers have a fiber diameter of from 0.05 to forty microns.
The following Examples are intended to illustrate the invention. In the Examples, all parts are by weight.
EXAMPLE I
To a conventional two percent asbestos slurry contain-ing 0.5% , (based on the weight of the asbestos) of Fluorad FC-126 fluorohydrocarbon surfactant ("Fluorad" is a Registered Trade Mark), was added twenty percent (based on the weight of the asbestos) of polyethylene chlorotrifluoroethylene powder.
The powder was mixed with the slurry to render the slurry uniform.
The slurry was then deposited onto a cathode screen by vacuum deposition substantially as described in Example I
of our copending Application No. 244,710.
The diaphragm was then dried in an oven at 100C
for eight hours. Thereafter, the diaphragm was heat treated to bond the asbestos fibers to each other as well as to the cathode, at 260C for one hour.
~ ~ .
The diaphragm was then mounted in a test chlor -alkali cell and brine electrolysis was carried out therewithin.
The cell having the diaphragm mounted therewithin produced 130 grams per liter of caustic at 95~ current efficiency.
EXAMPLE II
This Example illustrates the use of a cementing agent with a self-bonding fiber.
Following the procedure of Example I of Application No. 244,710, a polyethylene chlorotrifluoroethylene fiber slurry containing the same surfactant as defined therein was deposited on a cathode screen. After deposition, the fiber-screen assembly was dried in a vacuum oven at 100C. for a ,; ,,,r~ ., ' , .
`
10792,Z~
period of about eight hours. The dried fibers were then impregnated with a one percent solution of polyethylene chloro-trifluoroethylene in nitrobenzene at 70C as a cementing agent.
This was achieved by immersing the assembly within the solution. -Thereafter, the impregnated fiber-screen assembly was heated at 250C for about one-half hour to bond the fibers.
The cathode was then deployed in a brine electrolysis test cell. The cell produced a caustic concentration of 130 grams per liter with a 90% current efficiency.
' :i :
.
h~ .' 5 . ,'
Claims (11)
1. A diaphragm for an electrolytic cell, which comprises a body of fibers cemented one to another by a cement-ing agent consisting of a heat-fusible hydrophobic material and containing a wetting agent to counteract the hydrophobic character of said heat-fusible hydrophobic material, a wetting agent also being present in the fiber material when the latter, in the absence of a wetting agent, is hydrophobic in nature, said wetting agent consisting of a perfluorinated organic material or an inorganic material other than asbestos.
2. A diaphragm as claimed in claim 1, wherein the cementing agent is admixed with a slurry of said fibers prior to depositing the slurry on a cathode screen.
3. A diaphragm as claimed in claim 1, wherein the cementing agent is contacted with the fibers after deposition thereof from a slurry of said fibers on a cathode screen.
4. A diaphragm as claimed in claim 3, wherein the diaphragm is heat-treated after contacting the fibers with the cementing agent.
5. A diaphragm as claimed in claims 1, 2 or 3, wherein the cementing agent is present in an amount ranging from 10 to 30 percent by weight based on the weight of the fibers.
6. A diaphragm as claimed in claims 1, 2 or 3, wherein the cementing agent is present in an amount ranging from 15 to 25 percent by weight based on the weight of the fibers.
7. A diaphragm as claimed in claim 3, wherein the fibrous slurry is an asbestos slurry.
8. A diaphragm as claimed in claims 1 or 7, wherein the cementing agent is selected from the group consisting of fluorinated ethylene propylene, polyethylene tetrafluoro-ethylene,polyethylene chlorotrifluoroethylene, polychloro-trifluoroethylene, polyvinylidene fluoride and mixtures thereof.
9. A diaphragm as claimed in claims 1 or 7, wherein the cementing agent is polyethylene chlorotrifluoro-ethylene deployed as a solution in an organic solvent or as a dry powder material.
10. An electrolytic cell having a diaphragm as claimed in claim 1.
11. A cell as claimed in claim 10, which is a chlor -alkali cell for brine electrolysis.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US54868675A | 1975-02-10 | 1975-02-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1079225A true CA1079225A (en) | 1980-06-10 |
Family
ID=24189953
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA244,699A Expired CA1079225A (en) | 1975-02-10 | 1976-01-28 | Bonding of fibers for diaphragms in electrolytic cells |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS51104484A (en) |
| CA (1) | CA1079225A (en) |
| FR (1) | FR2300145A1 (en) |
| GB (1) | GB1533429A (en) |
| IT (1) | IT1053809B (en) |
| NL (1) | NL7601342A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1582593A (en) * | 1977-04-13 | 1981-01-14 | Ici Ltd | Diaphragm cells |
| US4447566A (en) * | 1983-01-27 | 1984-05-08 | Eltech Systems Corp. | Modified liquid permeable asbestos diaphragms with improved dimensional stability |
| US4665120A (en) * | 1983-01-27 | 1987-05-12 | Eltech Systems Corporation | Modified liquid permeable asbestos diaphragms with improved dimensional stability |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA74315B (en) * | 1973-01-17 | 1975-03-26 | Diamond Shamrock Corp | Dimensionally stable asbestos diaphragms |
-
1976
- 1976-01-28 CA CA244,699A patent/CA1079225A/en not_active Expired
- 1976-02-03 IT IT4793176A patent/IT1053809B/en active
- 1976-02-07 JP JP1186576A patent/JPS51104484A/en active Pending
- 1976-02-09 GB GB488876A patent/GB1533429A/en not_active Expired
- 1976-02-09 FR FR7603451A patent/FR2300145A1/en not_active Withdrawn
- 1976-02-10 NL NL7601342A patent/NL7601342A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| FR2300145A1 (en) | 1976-09-03 |
| NL7601342A (en) | 1976-08-12 |
| GB1533429A (en) | 1978-11-22 |
| JPS51104484A (en) | 1976-09-16 |
| IT1053809B (en) | 1981-10-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |