CA1124659A - Porous media to separate gases or vapors and coalesce entrained droplets - Google Patents
Porous media to separate gases or vapors and coalesce entrained dropletsInfo
- Publication number
- CA1124659A CA1124659A CA321,284A CA321284A CA1124659A CA 1124659 A CA1124659 A CA 1124659A CA 321284 A CA321284 A CA 321284A CA 1124659 A CA1124659 A CA 1124659A
- Authority
- CA
- Canada
- Prior art keywords
- bits
- micro
- mat
- gas
- vapor treating
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2055—Carbonaceous material
- B01D39/2058—Carbonaceous material the material being particulate
- B01D39/2062—Bonded, e.g. activated carbon blocks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
- B01D39/1638—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being particulate
- B01D39/1653—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being particulate of synthetic origin
- B01D39/1661—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being particulate of synthetic origin sintered or bonded
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2003—Glass or glassy material
- B01D39/2017—Glass or glassy material the material being filamentary or fibrous
- B01D39/2024—Glass or glassy material the material being filamentary or fibrous otherwise bonded, e.g. by resins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2055—Carbonaceous material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
- B01D2239/0291—Types of fibres, filaments or particles, self-supporting or supported materials comprising swelling polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/08—Special characteristics of binders
- B01D2239/086—Binders between particles or fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/1208—Porosity
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/1225—Fibre length
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/1233—Fibre diameter
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Nonwoven Fabrics (AREA)
- Filtering Materials (AREA)
- Paper (AREA)
- Laminated Bodies (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Orthopedics, Nursing, And Contraception (AREA)
- External Artificial Organs (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
A B S T R A C T
Disclosed are gas vapor treating mats consisting basi-cally of (a) very small (e.g. average 6.3 microns) diameter glass fibers composed of a plurality of filaments and of short length about 6.35 mm long, and intermixed therewith (b) so-called micro--bits of (i) an expanded thermoplastic styrene polymer and/or lower polyolefin and/or (ii) a flexible,foamed polyurethane, each of the members (i) and (ii) being non-brittle in ex-panded form, and (c) a minor amount of (i) an organic binding agent insoluble in cold water, but soluble in hot water and inert to the glass fiber and the polymer micro-bits and any other constituent of the mat as well as to the contents of the gaseous and/or vapor stream to which the mat is to be exposed, or (ii) a cobeat of wet lap cotton fibers and micro-bits. A gas separation embodiment of these mats also includes polyester fibers and activated carbon.
The mats have good tensile strength and porosity to provide maintained good flow-through rates but yet being sufficiently dense to enable filtering finely divided solid particles and/or entrained liquid droplets from aerosols or gases and/or vapor streams, as well as coalescing liquid droplets entrained in them, and also capable of separating some gases from such streams.
Disclosed are gas vapor treating mats consisting basi-cally of (a) very small (e.g. average 6.3 microns) diameter glass fibers composed of a plurality of filaments and of short length about 6.35 mm long, and intermixed therewith (b) so-called micro--bits of (i) an expanded thermoplastic styrene polymer and/or lower polyolefin and/or (ii) a flexible,foamed polyurethane, each of the members (i) and (ii) being non-brittle in ex-panded form, and (c) a minor amount of (i) an organic binding agent insoluble in cold water, but soluble in hot water and inert to the glass fiber and the polymer micro-bits and any other constituent of the mat as well as to the contents of the gaseous and/or vapor stream to which the mat is to be exposed, or (ii) a cobeat of wet lap cotton fibers and micro-bits. A gas separation embodiment of these mats also includes polyester fibers and activated carbon.
The mats have good tensile strength and porosity to provide maintained good flow-through rates but yet being sufficiently dense to enable filtering finely divided solid particles and/or entrained liquid droplets from aerosols or gases and/or vapor streams, as well as coalescing liquid droplets entrained in them, and also capable of separating some gases from such streams.
Description
POROUS ME~IA TO SEPARATE GASES~ LIQUID DROPLETS A~/OR
SOLID PARTI~L~S FRO~ C-~SES OR ~APO~S AND COALESCE
3rief Description Of The Invention This invention is that of (a) porous media, briefly called gas-~apor mats or gas-vapor ~iltering or treating mats, having good tensile strength and porosity to provide maintained good flow -through ra~es but ye~ being suff ciently dense to enable filter-ing finely divided solid particles and/or entrained liquid drop-lets from aerosols or gases an*/or vapor s~reams, as well as coalescing liquid droplets entrained in them, and also capable of separating some gases from such streams, and ~b) the preparation 0 of these mats.
m e gas-vapor trea~ing mats of the invention consist basi-cally of (a) very small (e.g. average 6.3 microns) diameter gl~ss ~ibers composed of a plurality of fila-ments and of short length about 6 . 35 mm long, and intermixed therewith (b) so-called micro-bits of (i) an expanded thermoplastic styrene-polymer and/or lower polyolefin and/or (ii) a ~lexible foamed polyurethane, each of the members (i) and (ii) being non-brittle in expanded form, and (c) a minor amount of (i~ an organic binding agent insoluble in cold water, but soluble in hot water and inert to the glass fiber and the polymer micro-bits and any other constituent o~ the mat as well as to the contents of the gaseous and/or ~apor stream to ~ich the mat is to be exposed, or ~ii) a cobeat (as described further below) of wet lap cotton fibers and micro-bits. A gas
SOLID PARTI~L~S FRO~ C-~SES OR ~APO~S AND COALESCE
3rief Description Of The Invention This invention is that of (a) porous media, briefly called gas-~apor mats or gas-vapor ~iltering or treating mats, having good tensile strength and porosity to provide maintained good flow -through ra~es but ye~ being suff ciently dense to enable filter-ing finely divided solid particles and/or entrained liquid drop-lets from aerosols or gases an*/or vapor s~reams, as well as coalescing liquid droplets entrained in them, and also capable of separating some gases from such streams, and ~b) the preparation 0 of these mats.
m e gas-vapor trea~ing mats of the invention consist basi-cally of (a) very small (e.g. average 6.3 microns) diameter gl~ss ~ibers composed of a plurality of fila-ments and of short length about 6 . 35 mm long, and intermixed therewith (b) so-called micro-bits of (i) an expanded thermoplastic styrene-polymer and/or lower polyolefin and/or (ii) a ~lexible foamed polyurethane, each of the members (i) and (ii) being non-brittle in expanded form, and (c) a minor amount of (i~ an organic binding agent insoluble in cold water, but soluble in hot water and inert to the glass fiber and the polymer micro-bits and any other constituent o~ the mat as well as to the contents of the gaseous and/or ~apor stream to ~ich the mat is to be exposed, or ~ii) a cobeat (as described further below) of wet lap cotton fibers and micro-bits. A gas
2~ separation embodiment o~ these mats also includes polyester fibers and activated carbon.
A web OL merel~ glass fibers such as the Owens-Corning DE 636 (described in EXample 1 ~elow) bound with polyvinyl alcohol (98y3 hydrolyzed) was made but its use has been rather rostricted~ For ,' ,; : , -exa~ple, it has been used as a battery plate separator and as the base for roof covering to be coated o~er with tar. Howe~er, no such web of glass fiber and polyvinyl alcohol (i.e called PVA) has been known ~or use in any such treatment of fluids as described above.
For many years various industries have been concerned with troublesome solid particles or ~ine droplets of liquids, or harm-ful gases released into working areas and often passing through vents or smoke stacks into the outside atm~sphere, thus provoking bothersome environmental problems. In some cases, it has been merely dust particles from working with inorganio materials such as recovering minerals from ores or ~rinding and polishing opera-tions.
In other cases also involved are liquid droplets entrained from chemical operations such as electropla~ing, spray coatln~ of one kind or another or produc~ion of certain synthetic resins. In still other situations it may be harm~ul gases, for exarnple, sul-fur dioxide carried into the atmosphere as lrom burning of high sul~ur con~ent fuel oils or bituminous coals. Produc-tion of a polyphenylene oxide-polystyrene alloy poly~er involves release in part of resin fines or pellets, dust particles and of oily plasti-cizer droplets entrained apparently as an aerosol into the air.
Some attempts to overcome some of these problems have been made by using (i) a filter medium such as a mat of glass fl~er.s 2~ held together Dy a phenol lormaldehyde resin binder~ or ~ii) glass wool air filters in window openings or other outlets. Howe~er, generally these filter media are bulky and yet not dense enough to restrain the finer particles or gases, thus still allowing undesirable fluid passage through them and thereby still to pass out to the atmosphere. m en also some of these mats, among other ~ ,L rZ ~ 3 9 shortcomings, have an undesirably limited tensile strength resulting in too frequen~ breaks requiring interrupting their use in undue time-consuming repair.
Other attempts include use of electric charging precipitators, such as the long known "Cottrell" ~ electric precipitators, but these are costly to install, operate and maintain, and do not restrain merely gases, for example, sulfur dioxide.
These disadvantages are o~ercome by the gas ~apor filter or treating mats o~ the invention~ Then too, these mats o~ the in~en-~ion show enhanced porosity and tensile s~rength o~er the above described glass ~ibers and PVA webs used as battery separators and in roof co~ering sheet~.
General Description_Of The In~ention Considered broadly, the gas-vapor treating mats of the in~en-tion comprise glass fibers (usually composed of a plurality of fila-ments) more o~ten selected as about 6.35 mm (millimeters) long and varying in diameter from about 3 to about 12 microns, and general-ly more readily applicable as of about 6.3 microns, intermixed with micro-bits of any o~ an expanded~ thermoplastic styrene polymer and c~n expanded lower polyole~m whIch is the pol~er of an ethylenically unsaturated hydrocarbon monomer having from 2 to 6 carbon atoms and a flexible foamed polyurethane (each said polymer being non-br~ttle in expanded form), and with the fiber glass and polymer micro-bits being (a) bonded (primarily at their intersections) by a compatible organic binder insoluble in cold water and soluble in hot water (e.g at about 80C. as for PV~) and inert to the micro-bits, the glass ~ib~rand any other mat constituent as well as the gases (in-cluding any entrained liquid droplets or aerosols and fine particles) that are to contact or be treated with the mat, or (b) held together by a cobeat of wet lap cotton fibers and polymer micro-bits ~as described below in Exarnple 5).
i~ . . . . .
, ~ lne mlcro- DitS can amoun-~ to from about 2 to about 50S~ of the mat, and beneLicially ~rom a~out 10 to about 35%, and ad~antageously from about 15 to abou~ 25~; and the compatible organic chemical binder present at from about 2~ to about 10~ and beneficially at from 5 to about 8%, or the cobeat of cotton fibers and micro-bits being from 5.8 to about 11%; and with the glass ~ibers present in an amount suLficient to make up the total of 100% content. m e tensile stren~th of the mats varies from about 0~9 to about 5.34 kg.
per cm. and the porosity varies from ab~ut 152 to 914 liters per lQ sq. dcm. (i.e. square ~ecimeter) a~ 0,43 kg.
~ ne micro-bi~s component o~ the gas-vapor treating mats of the inven~ion are micro-bits of any of an expanded, thermoplastic styrene-polymer or lower polyolefin9 non-brittle in expanded form, or of a flexîble foa.ned polyurethane likewise non-brittle in expanded form. These micro-bits of an expanded, ther~oplastic s~yrene-polymer or lower polyolefin are more lully described (as in my Canadian patent application ~erial ~lo. 295,012 file~ Janw~ 16, 1978, now Canadian Pate~t No. 1,093,749, issued Jan~ 13, 1981), as an ~$~nde~ form polymeriselected from a styrene polymer and a lower polyole~in from polye~hylene to poly-methylpentene9 and characterized by being in the form of micro-bits and (a) from about 40 to about 325 microns long and ~rom about 20 to about ~25 micrvns wide, (b) from substantially completely to entirely completely free o~ intact cells of the expanded polymer bit-pieces from which they ~ere pro-duced, tc) substantially wi'hout any uniformity in outline of the indïvidual micro-bits par~icles, and (d) in density from about 85 percent of, to about substantially the same as, *he specific unex-panded poly~er from which there was pro~ided the aforesaid expanded polymerO
~ese micro-bits of an expanded, thermoplastic styrene polymer . ;
or a lower polyolefin are produced from so-called bit pieces of any of the expanded the~mo?lastic, non-bri~tle in expanded form styrene -polymers or lower polyole~ins as starting materialO By "bi~-pieces"
is meant any of the discirete free-flowing forms of any of these s~yrene-polymers and lower polyolefins, such as (i) the various sizes of granules made by cutting the respective extruded polymer into fairly small lengths usually called pellets or crystal (as with a styrene-polymer) or pellets or cubes of a polyethylene-polys~yrene blend~ (ii) ~he various sizes OL styrenepolymer beads o~tained from suspension poly~erization or othe~ise as by molding the particles obtained by disintegrating any of these different polymer forms, (iii) the so-called l'grind" including the coarsely ground molded polymer or waste or o~her scrap such poly~er of various sizes9 e~
A web OL merel~ glass fibers such as the Owens-Corning DE 636 (described in EXample 1 ~elow) bound with polyvinyl alcohol (98y3 hydrolyzed) was made but its use has been rather rostricted~ For ,' ,; : , -exa~ple, it has been used as a battery plate separator and as the base for roof covering to be coated o~er with tar. Howe~er, no such web of glass fiber and polyvinyl alcohol (i.e called PVA) has been known ~or use in any such treatment of fluids as described above.
For many years various industries have been concerned with troublesome solid particles or ~ine droplets of liquids, or harm-ful gases released into working areas and often passing through vents or smoke stacks into the outside atm~sphere, thus provoking bothersome environmental problems. In some cases, it has been merely dust particles from working with inorganio materials such as recovering minerals from ores or ~rinding and polishing opera-tions.
In other cases also involved are liquid droplets entrained from chemical operations such as electropla~ing, spray coatln~ of one kind or another or produc~ion of certain synthetic resins. In still other situations it may be harm~ul gases, for exarnple, sul-fur dioxide carried into the atmosphere as lrom burning of high sul~ur con~ent fuel oils or bituminous coals. Produc-tion of a polyphenylene oxide-polystyrene alloy poly~er involves release in part of resin fines or pellets, dust particles and of oily plasti-cizer droplets entrained apparently as an aerosol into the air.
Some attempts to overcome some of these problems have been made by using (i) a filter medium such as a mat of glass fl~er.s 2~ held together Dy a phenol lormaldehyde resin binder~ or ~ii) glass wool air filters in window openings or other outlets. Howe~er, generally these filter media are bulky and yet not dense enough to restrain the finer particles or gases, thus still allowing undesirable fluid passage through them and thereby still to pass out to the atmosphere. m en also some of these mats, among other ~ ,L rZ ~ 3 9 shortcomings, have an undesirably limited tensile strength resulting in too frequen~ breaks requiring interrupting their use in undue time-consuming repair.
Other attempts include use of electric charging precipitators, such as the long known "Cottrell" ~ electric precipitators, but these are costly to install, operate and maintain, and do not restrain merely gases, for example, sulfur dioxide.
These disadvantages are o~ercome by the gas ~apor filter or treating mats o~ the invention~ Then too, these mats o~ the in~en-~ion show enhanced porosity and tensile s~rength o~er the above described glass ~ibers and PVA webs used as battery separators and in roof co~ering sheet~.
General Description_Of The In~ention Considered broadly, the gas-vapor treating mats of the in~en-tion comprise glass fibers (usually composed of a plurality of fila-ments) more o~ten selected as about 6.35 mm (millimeters) long and varying in diameter from about 3 to about 12 microns, and general-ly more readily applicable as of about 6.3 microns, intermixed with micro-bits of any o~ an expanded~ thermoplastic styrene polymer and c~n expanded lower polyole~m whIch is the pol~er of an ethylenically unsaturated hydrocarbon monomer having from 2 to 6 carbon atoms and a flexible foamed polyurethane (each said polymer being non-br~ttle in expanded form), and with the fiber glass and polymer micro-bits being (a) bonded (primarily at their intersections) by a compatible organic binder insoluble in cold water and soluble in hot water (e.g at about 80C. as for PV~) and inert to the micro-bits, the glass ~ib~rand any other mat constituent as well as the gases (in-cluding any entrained liquid droplets or aerosols and fine particles) that are to contact or be treated with the mat, or (b) held together by a cobeat of wet lap cotton fibers and polymer micro-bits ~as described below in Exarnple 5).
i~ . . . . .
, ~ lne mlcro- DitS can amoun-~ to from about 2 to about 50S~ of the mat, and beneLicially ~rom a~out 10 to about 35%, and ad~antageously from about 15 to abou~ 25~; and the compatible organic chemical binder present at from about 2~ to about 10~ and beneficially at from 5 to about 8%, or the cobeat of cotton fibers and micro-bits being from 5.8 to about 11%; and with the glass ~ibers present in an amount suLficient to make up the total of 100% content. m e tensile stren~th of the mats varies from about 0~9 to about 5.34 kg.
per cm. and the porosity varies from ab~ut 152 to 914 liters per lQ sq. dcm. (i.e. square ~ecimeter) a~ 0,43 kg.
~ ne micro-bi~s component o~ the gas-vapor treating mats of the inven~ion are micro-bits of any of an expanded, thermoplastic styrene-polymer or lower polyolefin9 non-brittle in expanded form, or of a flexîble foa.ned polyurethane likewise non-brittle in expanded form. These micro-bits of an expanded, ther~oplastic s~yrene-polymer or lower polyolefin are more lully described (as in my Canadian patent application ~erial ~lo. 295,012 file~ Janw~ 16, 1978, now Canadian Pate~t No. 1,093,749, issued Jan~ 13, 1981), as an ~$~nde~ form polymeriselected from a styrene polymer and a lower polyole~in from polye~hylene to poly-methylpentene9 and characterized by being in the form of micro-bits and (a) from about 40 to about 325 microns long and ~rom about 20 to about ~25 micrvns wide, (b) from substantially completely to entirely completely free o~ intact cells of the expanded polymer bit-pieces from which they ~ere pro-duced, tc) substantially wi'hout any uniformity in outline of the indïvidual micro-bits par~icles, and (d) in density from about 85 percent of, to about substantially the same as, *he specific unex-panded poly~er from which there was pro~ided the aforesaid expanded polymerO
~ese micro-bits of an expanded, thermoplastic styrene polymer . ;
or a lower polyolefin are produced from so-called bit pieces of any of the expanded the~mo?lastic, non-bri~tle in expanded form styrene -polymers or lower polyole~ins as starting materialO By "bi~-pieces"
is meant any of the discirete free-flowing forms of any of these s~yrene-polymers and lower polyolefins, such as (i) the various sizes of granules made by cutting the respective extruded polymer into fairly small lengths usually called pellets or crystal (as with a styrene-polymer) or pellets or cubes of a polyethylene-polys~yrene blend~ (ii) ~he various sizes OL styrenepolymer beads o~tained from suspension poly~erization or othe~ise as by molding the particles obtained by disintegrating any of these different polymer forms, (iii) the so-called l'grind" including the coarsely ground molded polymer or waste or o~her scrap such poly~er of various sizes9 e~
3.175 millimeter (i.e. ml.) thick, 6.35 ml. wide, and 9.5~5 ml. long,
5 and (iv) any other small sized shapes of any o~ them.
m e preparation and properties of flexible polyurethane foams are described, for ex~mple, in the "Handbook of Foamed Plastics", Bender, Rene ~., Section X9 pp. 173-236, Lake Publishing Corporation, Libertyville, Illinois, ~S.A. (1955), 'IPolyurethanes: Chemistry and Technology, Saunders & Frisch,Chapter V,I, Part II, m ~erscience Publishers, New York, N.Y., U.S.A. (1964)1 and "The Development and Use of Polyure~hane Foams'l, Doyle, E.N., pp. 233-256, McGraw Hill ~ook Company, ~ew York, N.Y " U.S.A. (1971).
m e flexible polyurethane foams useflll to proYide foamed poly-ure~hane micro-bits preferably should be no greater than 72.14 gm-per liter in density, beneficially ranging from about 360 to about 120 gm. per liter, and show excellent recovery af~er 75% de~lection with approximately less than 15~ loss in height (as determined by American Society of Testing ~aterials D-1564-64T).
The flexible foam polyurethanes are no~ ob~ained in the fore-, ~
~,. J :
going same bi~-pieces ~orr.s as are the styrene-polymers and lower polyolefins, bu~ r~her in continuous ~oamed blocks as a resul~ of the reaction that pro~ides the polyurethane. Accordingly, the foamed polyurethane blocks first are shredded into bit-pieces (for 5 example, similar to how they may be prepared for use in stuffing into various articles).
The.foamed polyurethane micro-bits are more fully described as comprising broken and interconnected strand portions from adjacent cells of the flexible foa~. which strand portions show substanttally total absence of intact cells and cell windows and are tripodal particles with generally uneven length legs, the strand portions having ~ook-like projections, indentations and flutes resulting from ~y destruction of the cells and cell windows of the starting ~lexible foam.
~ ~ . . . . . . . . .
The micro bits OL any expanded tnerr~oplastic~ non-brittle in expanded form s~yrene-polymer or lower polyolefin or flexi~le ~oamed polyure~hane are prepared by disi~tegrating the respective s~arting expanded polymer bi~-pieces in a com~inuti~g machine such as that produced by Fi~zpatric~ Company (of 832 Industrial Drive9 Elmhurst, Illinois 60120, U.S.A.) according to their Bulletin No. 152 copyright 1968 using the broached fixed blades (identified therein by ",Co~e DS225") to replace the blades or other com~inuting elements, mounted ~or ro~ation in ~he c~mminu~ing chamber model DASo6t both shown on that bulletin's page 5. That chamber is liquid-tightly capped, Lor example, by a cover such as shown in their Code M4436 or Code 1~A44D6 (upper half of page 3 of ~heir Bulletin 152).
m at model DAS06 comminuting chamber is recta~gular in hori-zon~al cross-sec~ion and has a pair o~ opposed parallel entirely ~ertical walls integrally joined at each o~ their opposite end~ by a separ~te one of a pair of opposed vertically arcuate walls each with its convex face exposed to the exteriorO
Sixteen identical, slat-shaped comminuting arms are separately removably but fixedly carried with their snugly adjacent to one another bases encircled about, and keyed to, the operating sha~t and in~ermediate its free ou~er mounting ends. m ese arms extend radially out Lrom the sha~t (P,g. 127 mm. from its axis to the outer , end of each arm) with the ~irst of each consecuti~e ~our o~ them / extending horizontally toward one arcuate wall, the secon~ of each four extending vertically, the third four of them extending toward the other arcuate wall 9 and the ~ourth four o~ them extending verti-cally downward.
Each ar~ is rectangular in cross-section in a plane running through the en~ire length of the shaft's axis and o~ that arm, and OL each arm 180 removed from it. The outer end of each arm meets a~ right angles with its two wider sides (5.4 mm. width) and its nar-row or impaGt side (9.5~5 mm. wide) facing ~he direction o~ rota~ionO
m at narro~l side also meets at right angles with the two wider sides which are parallel to one another for most o~ their width and with the trailing thiTd of their sur~aces tapering to one another and terminating in the kni~e edge of their trailing end.
~ ach free expo~ed end of the shaft extends through its respec-tive stuffing box in its neighboring one o~ the two parallel vertical walls on through a bearing carried on a respective trunnion af~ixed to the machine's foundation and spaced outwardly awa~J from the respec tive wall. A driYing pulley is mounted on each end of the shalt ex-tending outwardly ,rom its respective mounting trunnionO
The bottom o~ the commi~uting chamber i5 an exchangeable dish -shaped, arcuate screen cur~ed convexly downward with an inside radius ~0 (from the axis of the operating sha~t~ equal to the length of a ~ $ ~ ~
comminuting arr.l plus ~ mm. clearanCe . The screen's overall rec~angular peripheral o~ening has such dimensions and shape as to enable ~t to be removably ~itted in a li~uid-tight engagement ~Jith the bottom of the four walls of the comminuting chamber.
m e screen has s~aggered ro~s of~ for example, circular holes varying in diameter as from 0.102 to abou~ 3~175 mm. and closely spaced to one another with sufficien~ space between them for the screen ~o h~ld up under working conditions. 3 EXce~t ,or its starting material feed hopper inlet at one side o~ it, the rest of the chamber's cover is arcuate and convex upwardly with a radius (from the axis of the operating shaf~) suffi~
cien~ for -~he rotating arms to have a 0.762 mm. clearance from the in~arlly facing surfaces of a plurality (e.g. thr~e) pre-breaker bars (about 20.32 cm. long and 6.35 mmO wide) protruding for ~.175 ~. along their entire length into the interior of the comminuting chamber, and ex~ending spaced apart from one another and parallel to the axis of the operating shaft.
Thè selected driving pulley on the operating shaft is connected by driving belts extending from a motor shaft drive pulley and can be operated at speeds embracing the range of from about 4700 to about 8000 r.p.m., and more effectively ~rom about 5000 to about 7500 r.p~m m e in~en~ion includes also a form of these mats, whic`n can be called the gas-vapor adsorption filtering or treating mats. ~nese include the basic or primary constituents ta) the glass fibers, (b) ~5 the micro-bits, and (c) the organic bin~ ~ agent, each being generally within its earlier above recited respective range relative tv the others o~
them, together with an amount of finely diYided activated carbon (as primary gas-adsorbing agent) below ~hat at which undesirable dustin~
of~ of carbon particles can occur, a suf~icient amount o~ the cobeat to serve to restrain the carbon particles against dusting off, and . ~
, .
2~
~n amount of a ~iber-forming terephthalate polyester su~licient to hold the mat ' s tensile strength within its earlier above recited range without undesirable lowering o~ the mat's p~rosity~
Thus, ~or example, in addition to its three primary cons~ituents (a), (b) and (c), these adsorp~ion filtering and treating mats can contain, of their overall content, the activated carbon to a maximum of about 255$, the polyester fibers in ~he range ~rom about 2% to about 7.5~' and from about 2% to about 30~0 o~ cobeat.
`Any o~ the gas-adsorbing activated carbons from their various sources, for exampl~, charcoal~ coal, petroleum distillation residue ~r pecan nut shells, can be used.
The invention also involves the method of preparing these mats provided by the inventicn. Broadly the prepara~ion o~ the gas-vapor treating mats comprises dispersing in water in a pulper (as used in paper makin~) an amount o~ (a) micro-bits of any of an expanded, therrr~plastic styren ~polylrer and an expanded lower p~lyolefin from p~lyethyle~e to poly-methylpentene and a flexible polyurethane, each said polymer being non-brittle in its expanded ~orm, and (b) glass fibers composed o~ ~he glass filaments, as described above~ and agitating the mixture of ~a) and (b) for the brie~ time at least su~icient ~or each of them to be substantially ~ree of clumps and clusters and substantially uni-formly intermixed, and in the propor~ion of from about 5 to about 50 parts o~ the micro~bits to from about 4 to about 45 pa~s of the glass ~ibers, admixing an organic binding agent (as described ea~lier aboYe) or a cobeat (as described ~urther below) in an amount sufficien~ for the finished mat to ha~e tensile stren~th an~ rosity, with each of them bein~ within its respecti~e earlier above recited range;
then transferring the resulting mixture to a supply chest in a concentration of ~rom about 0~l % to 0.5~ o~ the admixed micro-bits and the glass fibers and therein agitating their mixture .~ 7~
.
merely suf~iciently to maintain a uniform aispersion.
The dispersion then is fed from the supply chest to the furnish box (of the Fourdr mier machine) at the ~ate, ~or example, from about 3.3 to 5.5 kg. (iOe. kilogram) per minute and at the same time is diluted uniformly with water fed into the fu~nish ~ox at the rate o~ from 3,800 to about 9,000 liters per minute.
m e resulting diluted ~urnish slurry then is fed onto the Fburdr~er screen moving at a rate to pro~ide a wet mat which after drying has a basis weight of ~rom about 2.25 to abou~ 22.5 kg., and continuously removing the wet mat from the screen and running it through a suitable drying operation.
The gas-vapor treating mat can b~ prepared by including adding to the mix~ure in the pulper, beneficially be~ore admixing any bind-ing agent a separate amount o~ each of sodium hexametaphosphate and concentrated sulfuric acid and in such proportion $o one another sufficient to lower the pH of the mixture to 205.
m e gasvapor adsorption treating mats are prepared by a com-bination o~ steps comprising preparing a cobeat suspension of wet la?
cotton fibers and micro-bits in water (as described further below) and separately a suspension of micro-bits in water in the proportion recited further below.
m en a furnish supply suspension is prepared by ad~ixing in water an amou~t of the cobeat suspension wit'nin a given range and addin~ a quan~ity o~ a ~iber~forming polyethylene terephthalate 2~ polyester in a quantity to partake in providing the ~inished mat with tensile strength within an effective range without adversely affecting its porosity. m en ~inely divided actiYated carDon admixed within the range up to a maximum of about 25% Of the planned total solids of ~he finished mat, and an aqueous suspensio~ of the micro-bits is added in an amount to provide in the finished mat from about lOy ~o about 30~0 of micro-bits.
_~ --10 3~
The remaining addition admixed is a suspension of glass fiDer.
micro-bits and binding a~ent, each within its respective range as earlier recited for the gas-vapor treating mat and so proportioned to the o~her solids ~or the finished mat to ha~e the planned tensile 5 stren~th and porosity. The ~inally resulting suspension ~rom all of these included constituents is fe~ to the furnish box within the rate of feed recited for the mats lacking the carbon and polyester, and there similarly diluted with water and then fed onto the Fourdrinier screen and dried as with the other mats.
lQ In each o~ the procedures preparing a mat wherein an organic binding agent is used, it is beneficial to add that agent to the sus-pension (being prepared) within the las~ minute or so o~ the agi~ation be~ore the suspension is to be fed to the (machine) supply chest and also tha~ the web lea~ing the Fourdrinier screen initially is subjected to radiant heat from a relatively close source at a temperature in the range of from about 600C.to about 700C.. m at rapidly causes solu-tion of the organic bin~ ~ agent in the water carried by the mat an~ e~ es the drying of theorsanic b ~ ~ agent at the intersections of the water~ luble constituents.
The preparation o~ any of the desired styrene-polymer, lower polyolefin or polyurethane micro-bits from starting bit-pieces of any of the respective expanded polymers (styrene-polymer, lower polyolefin or polyurethane) is illustrated in, but not restricted to, the follow-ing preparation of polystyrene micro~bits:
2~ EXample A -425 liters of expanding-agent-impregnated, extruded polystyrene pellets (crystal) expanded to from &~out 6.~ to about 12~7 mm. substantially round pellets having a bulk density o~ 12 grams per liter were commi-nuted in a comminuting machine (as described earlier above) equipped with an input ~eeder 10.16 cm. in diameter by 7.62 cm. long and a bottom arcuate screen with holes of 0.1016 mm. diameter.
-11;
~, , .
, ; : . ~ . -The rotor was set to run at 6,ooo r.p.m. and the feeder set to charge the expanded polystyrene bit-pieces at the rate o~ 35.4 liters every 5 minutes (i.e. 425 liters per hour) The starting expanded polystyrens bit-pieces to be introduced into the feeder were wetted with sufficient water substantially completely to cover their outer surfaces. The ~hus wetted expanded polystyrene bit-pieces were charged in~o the feeder continuously at a ra~e o~ ~5.4 liters every 5 minutes, while at the same time water was injected into ~he commi~
nuting chamber through the two 1.6 mm. diameter jet orifices at a rate of 7.57 liters per minute.
m e mixture of the expanded polystyrene micro-bits l~aving the screen bottom of the comminuting chamber was collected in an open tank with a bottom drain plug, wherein the free water settled to the bottom and the polystyrene micro-bits with the bound water held by them (in the proportion of 2 parts of micro-bits to 98 parts of water) due to the entrapped air, rose on top of the free water. The free water was drained off leaving behind a plastic mass of the resulting expanded polysbyrene micro-bits in the water physically bound to them. m e plastic mass weighed 255.15 kilos and contained 5.1 kilos of micro-bits with 250.05 kilos of water bound by them.
27.24 kilos of this plastic mass, placed in a close weave double cotton bag, then were subjected to pressure until 22071 liters o~
water were expressed. The ~emaining 4.08 kilos containing 544 grams of ~ expanded polystyrene micro-bits then were dried in an open dish in an oven maintained at 43.33C.
Micro~bits of any other thermoplastic expanded styrene-polymer or lower polyolefin, each non-brittle in expanded form, or of any flexible foamed (i.e. expanded) polyurethane non-brittle in its foam or expanded fo~m can be prepared by repeating Example A and replacing its starting polystyrene bit-pieces by bit-pieces of any of these other applicable expanded polymers. Thus, each such repeat of Ex~mple A
starting with the micro-bits of each such other applicable expanded polymer is ~o be considered as i~ incorporated herein in full as a separate example, thereby avoiding unnecessarily extending ~his ~ 5 speci~ication.
m e preparation of the gas-vapor treating mats of the in~ention is illustrated by, but not limited to, the following examples:
EXam~le 1 asic Gas-vapor Treatment Mat: Into 15 ,1~9 liters of water charged into a tpaper ma~ing) pulper (of ve~y little greater capacity), there was ~ed by an endless belt conveyor 23.27 kilos (dry basis) o~ polystyrene micro-bi~s (in ~he form of water-bound product containing 8% micro-bits solids). m e pulper contents mixture then was agitated for 3 minutes by its rotor turning at 506 revolutions per minute (r.p.m.) thereby dispersing the micro-bits in the water.
~7hile agitating the mixture, 22.73 kilos o~ sodium hexametaphos-phate were admixed and followed by admixing 3.785 liters of concentrate~
sulfuric acid (98.6,b H2S04). That brought the pH of the batch to 2.5.
m e agitation was stopped while there were added (~rom a number o~ cartons) a total of 113.64 kilos o~ 6.35 millimeters (length) glass fibers (diameter 6.3 microns) Owens-Corning electrical grade DE 636 as thè number o~ ~ilaments per bundle (and bound by a starch, oil and cationic surfactant binder).
m e rotor agitation was resumed and continued for 10 minutes, during the las~ 30 seconds of which 10.25 kilos of (cold) water-swell-able polyvinyl alcohol (98% hydrolyzed) (hereina~ter called PVA) ~ibers were added as binding agent. m e thus completed initial pulper mix was pumped to the beater chest (serving only as holding ~acility to receive amounts o~ pulper mix) and agitated ~here merely ~ufficiently to maintain the insolubles in suspension.
7570 liters of ~rinse) water then were added to the pulper and ;~ ```
~ ;~
agitated to suspend any glass ~ibers and/or micro-bits which settled out and remained behind while the ini~ial pulper mix was being pumped t~ the beater chest. The resulting so-called pulper rinse mix then was pumped to the beater chest and ~here admixed into the initial pulper mix to provide the starting mat~m~king mix containing o.64 solids.
m is starting mat-making mix then was pumped to the machine ohes~
(also a supply holding chest) with its contents maintained under agita-tion also as in the beat~r chest. From this supply chest ~he mat-making mix was fed to ~he furnish box for the Fourdrinier at a ra~te of 4.32 kg.
solids per minute and there combined with clear dilution water at a rate of 6056 LPM tliters per minute).
The resulting uniform web-furnish slurry (as diluted in the furnish bo~ was fed onto the traveling Fourdrinier screen (86 strands 1~, in the machine direction by 60 strands across) moving at a rate of 15.24 meters per minute (i.e. MPM) to enable providing an initial web mat whic after 1ater ~inished drying showed a basis weigh~ o~ 19.1 kg.
The 9.525 m~n. thicls wet mat (on the Fourdrinier) a~ter passing the suction boxes under the leaving end of the Fourdrinier scre~n con-tinued onto an endless belt conveyor (a 112 by 84 mesh screen) also at 15.24 I~PM. Then after about 1.5 meters beyond that end of the Fourdrinier~ the we~ mat (on that conveyor) passed about 10 cm. below a battery (about 60.5 cm. long~ of infrared lamps (52.4 kilowat~s, at ~.8 amperes, 480 volts, single phase 60 cycle) pro~iding at the mat surface a rheostat set temperature o~ possibly 649C. m e exposure o. the wet m~t to that temperature thus for about 2.4 seconds quickly caused solution of the PVA, Ihe partially dry web continued through a tunnel dryer (about 3.67 meters long 'Dy 1 . 83 meters wide) proYiding a temperature of about 121C. and then alternated in sequence o~er one and then under the ~i next of each of a series of six dryer drums (the first drum providing a temperature of 113C. with the temperature increased at each of them that followed with the last drum maintained at 127~). me finally dry mat then passed throu~h a pair of ~ension rollers and onto a wind up drum. m e dry mat web with a smooth surface on each side wound up easily around that drum without a~y tears or wrinklesO
At its basis of 19.1 kilos, the ~inished gas-vapor treating web showed a porosity value (by Gurley porosity meter) of about 602.8 liters per minute (i.e. LPM) per square decimeter (i.e. sq. dcm.) of sur~ace at a tes~ dif~erential air pressure of 2.54 centime~ers of water (gage).
Based on the starting amoun~s of the essential materials, the finished dry gas-vapor treating mat contains about 15.8% of the ex-panded polystyrene micro-bits~ about 77.2~ of glass fibers and about 6.97~' of polyvinyl alcohol binder. The content of thsse essential constituents may be varied in accordance with desired variations in porosity~ gas or vapor ~luid flow rate and density by suitable varia-tions in the constituents content. For example7 the porosity can be decreased by lowering the micro bits content to any le~el do~m to a mini~um of about 2% without corresponding decrease in tensile strength.
Alternatively, the porosity and flow rate can be increased by increasing ~he micro--bits content, as in some formulationst to any level even up to about 50%
Example 1 can be repeated by reducing the ~uantity o~ sulfuric acid in part or as a whole and also by reducing the amount of sodium hexametaphosphate (ordinarily used to e~lance glass fibers dispersion~
in whole or in part in preparing the initial pulper suspension, in ~iew of the indication that the micro-bits appear to enhance dis persion of the solid constituen~s during agitation in the water.
~0 Depending on the anticipated ultimate use o~ the ~as-vapor treating mat its basis weight can be reduced or enlarged by either decreasing or increasing the solids content in the aqueous ~urnisn in the furnish box or increasing or reducing the speed of the Fourdrlnier screen~ m e replacement may be in part or as a whole.
Example 2 - ~
Micro~Bits: Into a 3.5 liter stainless steel beaker containing 3 liters of water, there was dispersed 21.5 grams of (~urniture grade) flexible polyurethane m,icro-bits containing 20% solids (thus 4.3 grams of dry micro-bits and 17.5 cc. of water) by an air driven stirrer.
m en 15 grams OL the same 0.635 cm. length DE 636 glass fib~r las of Example 1) were added and a~itation continued. In the last 10 minutes of an hour of stirring there was admixed 1.375 grams of the PVA tsame as in Example 1).
Six-tenths o~ the resul~ing dispersed slurry then was poured over the hand sheet screen of an ordinary laboratory paper hand sheet former (having a 30.48 cm. high brass tank with a 20.32 cm. square base) and mixed from the top. The water discharge valve was opened with the solids o~ the slurry developing in sheet ~orm on the screen and the water dripping through the scree~ by gra~ity from the increas-ing density slurry. After no further water drained off by gravity, the wet sheet was dried in a drying oven by a hot air stream at 121C.
~lowing through it for 5 minutes. The resulting 12.57 grams dry hand sheet mat showed a tensile strength of 1.41 kilos per cm. and porosity of 579 liters per square decimenter per minute.
Example 2 includes no sodium hexametaphosphate and sulfuric acid because the micro-bits tend to enhance dispersion of the glass fibers which as introduced into the water appear to a large extent in a multitude of bundles of the fibers. Other mats of this invention can be made similarly without these two inorganic substances,from micro-bits o~ the other effective polymers.
....
. . , . . ~
Example 2 was repeated except that during the agitation a~ter admixin~
~he glass fibers, i~stead of PVA there was admixed 60 grams of the cobea~ suspension o~ Example 5 amounting to 1.2 grams of the cobeat solids (composed of beater beaten, interlocked wet lap cotton ~ibers and polystyrene micro-bits). m e preparation o~ the mat then was completed as in EXample 2. m e resulting dry mat showed porosity of 335 1iters per sq~ dcm. per minute, at 0.45 kg. dif~erential pressure (gage), and tensile strength of 0.61 kg. per cm.
EXam le 4 - ample 3 With Pol~y_ ne ~Replacin~ P~o~y~rethane:
EXample 3 was repeated by using polystyrene micro-bits instead-of the polyurethane mlcro-bI~s, and also cobeat as the binder instëad of PVA. The resulting dry web showed tensile streng~ of 0.22 kg.
per cm. and porosity of 5,377 LPM at 0.45 kg. per cm. differential pressure (gage).
m e adsorbent (oonstituent) containing gas-vapor ~iltering or treating mats of this in~ention are illustrated by, but not restricted to, the following:
Example 5 - ctivated Carbon-containing Adsorption Mat: ~a?
Cobeat Suspension PreE~ n: A cobeat suspension (so-called because wet lap cotton ~ibers and micro-bits are beaten together in a beater) was prepared by charging 363.6 kilos (dry basis) of wet lap cotton fibers (as used in paper making, containi~g 1454.4 liters o~ water in ~ the ~ibers) and 181.8 kilos (dry basis) o~ polystyrene micro-bits t6Yo solids with 2848.5 liters of bound water) into 13,354 liters of water in a pulper and agitated ~or 3 minutes (as in Example 1) thereby dis persing the cotton fibers and micro-bits free of clumps and clusters in the water.
That cotton fibers and micro-bits dispersion was pumped to a (paper making) beater having its pressure roll set at 65% o~ maximum and run at 110 r.p.m. for 6 hours (when the freeness starting at 760 .
.
was ~ound to have dropped to 600). The roll setting then was changed to provide more fibrillation and less cutting action, by using only the brush roll pressure with the roll barely contacting the bed. m e desired end occurred in two hou~s whe~ the ~reeness was ~ound reduced to 450. The beater content (now the cobeat suspension) ~as retained in the beater under merely sufficient agitation ~or the dispersion to remain in~c~uspension for later use.
The term ~'freeness~' used hereinabove is a term commonly used concerning the pulp in paper making, and is defined in U.S.
Patent 3,293,114 of December 20, 1966 (Column 3, lines 27-50 as:
"Freeness of pulp is a measure of the rate ~ flow of water through the pulp and is measured in accordance with the - Tappi Standard T 227 m-~8, also referred to as the Canadian Standard Freeness".
The wet làp cotton fibers are those commonly used in writing paper making to provide its cotton rag content. They are prepared for the most part from cotton fabric cuttings and cotton linters which are washed (bleached if necessary) and separated into fibers (as in a hollander) of from about 4.73 mm. to about 1.27 cm. in length, fed to a wet lap machine and from it as a web between pressure rolls and lea~ing as a web about 2.1 mm. thick (containing about 80% moisture) and then lapped up and back over and o~er on a pallet usually to a pile of about 363.8 kilos gross weight.
~ : Into 7570 liters of water in the pulper, there was admixed 136.4 kilos (dry basis) of the polystyrene micro-bits (as the water-bound product containi~g 16% micro bits solids and 715.9 liters of water) and agitated to a uniform dispersion and maintained under merely suf~icient agitation for that until shortly needed.
~ : A ~urnish supply suspension was prepared in a beater chest (i) by feeding into it 30,280 liters of water, (ii) admixing into the water 189.3 liters of the foregoing cobeat sus pension, thus proYiding a diluteA cobeat suspension, (iii) followed by admixing 91 kilos o~ readily wa~er dispersible, se~i -dull, opticzlly whitened polyethylene t~rephthala~e ~ D~e~
: ficially in 1.27 ~m. long ~iber~ o~ 1~5 denier gpu~ by con~entlonal melt process9 ha~ing a special finish compatible with most anionic, cationic or nonionic binders (and providing rapid and excellent dis-persion with a wide ~ariety of rurnish ~ystems ~nd additi~es~, and solution viscosity of 770 ~ 20 of 1/2 gram dissolved in 50 ml. of solvent (by w~ight~ 40 parts to tetrachloroethane and 60 parts phenol) at 25C. (solution ~isoosity is the ~iscosity of the polymer solution divided by the vi cosity of the solYenty with the result minus one multiplied by 1000); mel~ing point 48.67C., non-shrinka31e in boiling water, and elongation at break 45~ (available as TREVIRA 101, product of American Hoechst Corporation, Fibers Di~ision, Spartenburg, South Carolina 29301~the incorporatiQn of polyethylene terephthalate f~s in the suspension requires a relatively low solids content;
(iv) admixing 172~7 ~ilos of finely divided activated carbon (Nuchar S-N
product of ~restvaco Corporation, Covington, Va. 24426); and also (v) admixing the ~oregoing micro-bits suspension containing the 136 4 kilos (dry basis) of polystyrene micro-bits as the water-bound product ~avin~ abou~ 1656 micro-bits solids) thereby adding 716 liters of water to the 7570 liters initially included; and finally (vi) adding 4163.5 liters o~ the cobeat suspension (containing 193.4 kilos of solids) and 15,140 liters of the JUSt below identified glass fibers, micro-bits and binder suspension containing 187.7 kilos o~
suspended solids.
mis ~us-pension was prepared by the proGedure used in (the first 4 paragraphs of) EXample 1 by charging into a pulper 11,354 liters of water, admix-- ing 22.73 kilos (dry basis) of polystyrene micro~bits as the water -bound product (containing 65~ solids and 356 liters of water), dis solving 22.73 ~ilos of sodium hexametaphosphate and 3.8 liters of sul~uric acid (98.6%)9 and admixing 113.64 kilos of the same 6.35 mm.
length glass fibers and 10.23 kilos o~ the same PVA ~ibers. This suspension then was pumped to a beat~r chest.
*Trademark - 19 _ m e pulper then was rinsed by adding 3785 liters of water and agitating the content as in Example 1. The resulting rinse suspen-sion then was admixed with the pulper suspension in the beater chest9 thus providing the glass fibers, micro;;bits and binder suspension, as ~he second member o~ the constituent (vi) of the ~urnish supply suspension.
While maintained under agitation in the beater supply chest, this uniformly admixed furnish supply suspension was fed to the Fourdrinier machine head box at the same rate and admixture with dilution water as in Example 1~ and onto ~he moving FOurd~inier screen. A~ter passing the suction boxes, the resulting wet web continued onto the endless belt conveyor and then was dried by passing in sequence under the battery of infrared lamps through the tunnel dryer and under and oYer the series o~ six dryer d~ums.
The final activated carbon-containing adsorbing mat was uni-form in appearance with a basis weight o~ 15 to 15.45 kg. porosity o~ 353.7 liters per minute per square decimeter, and tensile strength of 1.074 kilos per cm. in the machine direction and 0.895 kilos per cm. in the cro3s direction.
m e polystyrene micro-bits of Examples 1, 4 and 5 can be re-placed in par~ or as ~ ~hole by those of any other of the applicable expanded ~hermoplastic styrene-polymers or lower polyole~ins or of flexible polyurethanes each non-~rittle in expanded form. Thus, each , .
such repeat of Examples 1, 4 and 5 by the just indicated replacement 2~ o~ expanded polystyrene micro-bits is ~o be considered as if occurring herein in full as a complete example, thereby a~oiding making ~his specification prolix. m e lower polyolefins from polyethy~ene to poly-methylpentene include also polypropylene and polybutene.
In any of Examples 1 to 5, and any of t~e ~ust above indicated modifications of any of them, the micro-bits can be provided with any .
--2~
, - :
amount of water held by ~hem ~s well as in the dry state. The micro -bits were provided in these examples as used along with di~ferent amounts ~f water held by them, because o~ their ready availability in that form and their ~hus lower eost.
Similarly, the cotton fibers used in preparing the cobeat were provided in their fo~ as wet lap cottoa~ fibers~ ordinarily contain ing about 80% of water, because of the economy in doing sO. Howe~er, that does not preclude using ~hese cot~on fibers in t~e dry state ~hen thus aYailable or desired ~or any particula~ reason.
The West~aco's NUCHAR~ -N acti~ated carbon in EXample 5 can be replaced by any other Westvaco actiYated carbon. For exa~ple, if the mat is to be used ~or adsorbing pnenol, WestYacO~s NUCHAR N A ~yield-ing an acid wash water when washed in wa~er) would be beneficial be-cause that acid grade mani~ests higher adsorption o~ phenol~
Either of these two grades of activat~d carbon ~an be replaced by any of the others available, for examp~e, DARCO now available from I.C.I. (U.S.A~) Ltd., and the NORIT product of American Norit Co. ~ne Bar~eby-Cheney activated carbon from pecan nut shells is highly ef~ec-ti~e, ~or.example, in the adsorption o~ sulfur dioxide from a gas stream, for which it showed a very much greater adsorption capacity tha an activated carbon from another source. Thus, Example 5 is to be considered as if present~d written out in full with its activated carbon replaced by the ~a~neby-Cheney product.
The polyester of Example 5 can be replaced by any oth~r fiber -forming terephthalate polyester, f ~ example, the FORTREL poly-ethylene terephthalate and th~ KOD~ ~imethyl 1.4-cYclo~exane di~
methanol. Example 5 and the thus resulting examples derived from it are to be considered as if presented as written out in full with the polyester separately respectively replaced by each one of these other polyesters. ~ny of them can be used in any of the available 1.5 and 3 denier diameters.
~21~
The mats of this in~ention are ef~ec~ive for removal and/or recovery o~ various gases or ~apors, either inorganic or organic, for example, sulf~r dioxide, chlorinated alkanes such as carbon tetrachloride and other chlorinated alkanes~ and benzene and phenol~
While the in~ention has been e~plained by detailed description of certain specific embodiments of it, it is understood t~at various substitutions or modifica~ions ca~ be made in any o~ them within the scope o~ the appended claims which are i~tended to co~er also equi-~alents of these embodiments.
m e preparation and properties of flexible polyurethane foams are described, for ex~mple, in the "Handbook of Foamed Plastics", Bender, Rene ~., Section X9 pp. 173-236, Lake Publishing Corporation, Libertyville, Illinois, ~S.A. (1955), 'IPolyurethanes: Chemistry and Technology, Saunders & Frisch,Chapter V,I, Part II, m ~erscience Publishers, New York, N.Y., U.S.A. (1964)1 and "The Development and Use of Polyure~hane Foams'l, Doyle, E.N., pp. 233-256, McGraw Hill ~ook Company, ~ew York, N.Y " U.S.A. (1971).
m e flexible polyurethane foams useflll to proYide foamed poly-ure~hane micro-bits preferably should be no greater than 72.14 gm-per liter in density, beneficially ranging from about 360 to about 120 gm. per liter, and show excellent recovery af~er 75% de~lection with approximately less than 15~ loss in height (as determined by American Society of Testing ~aterials D-1564-64T).
The flexible foam polyurethanes are no~ ob~ained in the fore-, ~
~,. J :
going same bi~-pieces ~orr.s as are the styrene-polymers and lower polyolefins, bu~ r~her in continuous ~oamed blocks as a resul~ of the reaction that pro~ides the polyurethane. Accordingly, the foamed polyurethane blocks first are shredded into bit-pieces (for 5 example, similar to how they may be prepared for use in stuffing into various articles).
The.foamed polyurethane micro-bits are more fully described as comprising broken and interconnected strand portions from adjacent cells of the flexible foa~. which strand portions show substanttally total absence of intact cells and cell windows and are tripodal particles with generally uneven length legs, the strand portions having ~ook-like projections, indentations and flutes resulting from ~y destruction of the cells and cell windows of the starting ~lexible foam.
~ ~ . . . . . . . . .
The micro bits OL any expanded tnerr~oplastic~ non-brittle in expanded form s~yrene-polymer or lower polyolefin or flexi~le ~oamed polyure~hane are prepared by disi~tegrating the respective s~arting expanded polymer bi~-pieces in a com~inuti~g machine such as that produced by Fi~zpatric~ Company (of 832 Industrial Drive9 Elmhurst, Illinois 60120, U.S.A.) according to their Bulletin No. 152 copyright 1968 using the broached fixed blades (identified therein by ",Co~e DS225") to replace the blades or other com~inuting elements, mounted ~or ro~ation in ~he c~mminu~ing chamber model DASo6t both shown on that bulletin's page 5. That chamber is liquid-tightly capped, Lor example, by a cover such as shown in their Code M4436 or Code 1~A44D6 (upper half of page 3 of ~heir Bulletin 152).
m at model DAS06 comminuting chamber is recta~gular in hori-zon~al cross-sec~ion and has a pair o~ opposed parallel entirely ~ertical walls integrally joined at each o~ their opposite end~ by a separ~te one of a pair of opposed vertically arcuate walls each with its convex face exposed to the exteriorO
Sixteen identical, slat-shaped comminuting arms are separately removably but fixedly carried with their snugly adjacent to one another bases encircled about, and keyed to, the operating sha~t and in~ermediate its free ou~er mounting ends. m ese arms extend radially out Lrom the sha~t (P,g. 127 mm. from its axis to the outer , end of each arm) with the ~irst of each consecuti~e ~our o~ them / extending horizontally toward one arcuate wall, the secon~ of each four extending vertically, the third four of them extending toward the other arcuate wall 9 and the ~ourth four o~ them extending verti-cally downward.
Each ar~ is rectangular in cross-section in a plane running through the en~ire length of the shaft's axis and o~ that arm, and OL each arm 180 removed from it. The outer end of each arm meets a~ right angles with its two wider sides (5.4 mm. width) and its nar-row or impaGt side (9.5~5 mm. wide) facing ~he direction o~ rota~ionO
m at narro~l side also meets at right angles with the two wider sides which are parallel to one another for most o~ their width and with the trailing thiTd of their sur~aces tapering to one another and terminating in the kni~e edge of their trailing end.
~ ach free expo~ed end of the shaft extends through its respec-tive stuffing box in its neighboring one o~ the two parallel vertical walls on through a bearing carried on a respective trunnion af~ixed to the machine's foundation and spaced outwardly awa~J from the respec tive wall. A driYing pulley is mounted on each end of the shalt ex-tending outwardly ,rom its respective mounting trunnionO
The bottom o~ the commi~uting chamber i5 an exchangeable dish -shaped, arcuate screen cur~ed convexly downward with an inside radius ~0 (from the axis of the operating sha~t~ equal to the length of a ~ $ ~ ~
comminuting arr.l plus ~ mm. clearanCe . The screen's overall rec~angular peripheral o~ening has such dimensions and shape as to enable ~t to be removably ~itted in a li~uid-tight engagement ~Jith the bottom of the four walls of the comminuting chamber.
m e screen has s~aggered ro~s of~ for example, circular holes varying in diameter as from 0.102 to abou~ 3~175 mm. and closely spaced to one another with sufficien~ space between them for the screen ~o h~ld up under working conditions. 3 EXce~t ,or its starting material feed hopper inlet at one side o~ it, the rest of the chamber's cover is arcuate and convex upwardly with a radius (from the axis of the operating shaf~) suffi~
cien~ for -~he rotating arms to have a 0.762 mm. clearance from the in~arlly facing surfaces of a plurality (e.g. thr~e) pre-breaker bars (about 20.32 cm. long and 6.35 mmO wide) protruding for ~.175 ~. along their entire length into the interior of the comminuting chamber, and ex~ending spaced apart from one another and parallel to the axis of the operating shaft.
Thè selected driving pulley on the operating shaft is connected by driving belts extending from a motor shaft drive pulley and can be operated at speeds embracing the range of from about 4700 to about 8000 r.p.m., and more effectively ~rom about 5000 to about 7500 r.p~m m e in~en~ion includes also a form of these mats, whic`n can be called the gas-vapor adsorption filtering or treating mats. ~nese include the basic or primary constituents ta) the glass fibers, (b) ~5 the micro-bits, and (c) the organic bin~ ~ agent, each being generally within its earlier above recited respective range relative tv the others o~
them, together with an amount of finely diYided activated carbon (as primary gas-adsorbing agent) below ~hat at which undesirable dustin~
of~ of carbon particles can occur, a suf~icient amount o~ the cobeat to serve to restrain the carbon particles against dusting off, and . ~
, .
2~
~n amount of a ~iber-forming terephthalate polyester su~licient to hold the mat ' s tensile strength within its earlier above recited range without undesirable lowering o~ the mat's p~rosity~
Thus, ~or example, in addition to its three primary cons~ituents (a), (b) and (c), these adsorp~ion filtering and treating mats can contain, of their overall content, the activated carbon to a maximum of about 255$, the polyester fibers in ~he range ~rom about 2% to about 7.5~' and from about 2% to about 30~0 o~ cobeat.
`Any o~ the gas-adsorbing activated carbons from their various sources, for exampl~, charcoal~ coal, petroleum distillation residue ~r pecan nut shells, can be used.
The invention also involves the method of preparing these mats provided by the inventicn. Broadly the prepara~ion o~ the gas-vapor treating mats comprises dispersing in water in a pulper (as used in paper makin~) an amount o~ (a) micro-bits of any of an expanded, therrr~plastic styren ~polylrer and an expanded lower p~lyolefin from p~lyethyle~e to poly-methylpentene and a flexible polyurethane, each said polymer being non-brittle in its expanded ~orm, and (b) glass fibers composed o~ ~he glass filaments, as described above~ and agitating the mixture of ~a) and (b) for the brie~ time at least su~icient ~or each of them to be substantially ~ree of clumps and clusters and substantially uni-formly intermixed, and in the propor~ion of from about 5 to about 50 parts o~ the micro~bits to from about 4 to about 45 pa~s of the glass ~ibers, admixing an organic binding agent (as described ea~lier aboYe) or a cobeat (as described ~urther below) in an amount sufficien~ for the finished mat to ha~e tensile stren~th an~ rosity, with each of them bein~ within its respecti~e earlier above recited range;
then transferring the resulting mixture to a supply chest in a concentration of ~rom about 0~l % to 0.5~ o~ the admixed micro-bits and the glass fibers and therein agitating their mixture .~ 7~
.
merely suf~iciently to maintain a uniform aispersion.
The dispersion then is fed from the supply chest to the furnish box (of the Fourdr mier machine) at the ~ate, ~or example, from about 3.3 to 5.5 kg. (iOe. kilogram) per minute and at the same time is diluted uniformly with water fed into the fu~nish ~ox at the rate o~ from 3,800 to about 9,000 liters per minute.
m e resulting diluted ~urnish slurry then is fed onto the Fburdr~er screen moving at a rate to pro~ide a wet mat which after drying has a basis weight of ~rom about 2.25 to abou~ 22.5 kg., and continuously removing the wet mat from the screen and running it through a suitable drying operation.
The gas-vapor treating mat can b~ prepared by including adding to the mix~ure in the pulper, beneficially be~ore admixing any bind-ing agent a separate amount o~ each of sodium hexametaphosphate and concentrated sulfuric acid and in such proportion $o one another sufficient to lower the pH of the mixture to 205.
m e gasvapor adsorption treating mats are prepared by a com-bination o~ steps comprising preparing a cobeat suspension of wet la?
cotton fibers and micro-bits in water (as described further below) and separately a suspension of micro-bits in water in the proportion recited further below.
m en a furnish supply suspension is prepared by ad~ixing in water an amou~t of the cobeat suspension wit'nin a given range and addin~ a quan~ity o~ a ~iber~forming polyethylene terephthalate 2~ polyester in a quantity to partake in providing the ~inished mat with tensile strength within an effective range without adversely affecting its porosity. m en ~inely divided actiYated carDon admixed within the range up to a maximum of about 25% Of the planned total solids of ~he finished mat, and an aqueous suspensio~ of the micro-bits is added in an amount to provide in the finished mat from about lOy ~o about 30~0 of micro-bits.
_~ --10 3~
The remaining addition admixed is a suspension of glass fiDer.
micro-bits and binding a~ent, each within its respective range as earlier recited for the gas-vapor treating mat and so proportioned to the o~her solids ~or the finished mat to ha~e the planned tensile 5 stren~th and porosity. The ~inally resulting suspension ~rom all of these included constituents is fe~ to the furnish box within the rate of feed recited for the mats lacking the carbon and polyester, and there similarly diluted with water and then fed onto the Fourdrinier screen and dried as with the other mats.
lQ In each o~ the procedures preparing a mat wherein an organic binding agent is used, it is beneficial to add that agent to the sus-pension (being prepared) within the las~ minute or so o~ the agi~ation be~ore the suspension is to be fed to the (machine) supply chest and also tha~ the web lea~ing the Fourdrinier screen initially is subjected to radiant heat from a relatively close source at a temperature in the range of from about 600C.to about 700C.. m at rapidly causes solu-tion of the organic bin~ ~ agent in the water carried by the mat an~ e~ es the drying of theorsanic b ~ ~ agent at the intersections of the water~ luble constituents.
The preparation o~ any of the desired styrene-polymer, lower polyolefin or polyurethane micro-bits from starting bit-pieces of any of the respective expanded polymers (styrene-polymer, lower polyolefin or polyurethane) is illustrated in, but not restricted to, the follow-ing preparation of polystyrene micro~bits:
2~ EXample A -425 liters of expanding-agent-impregnated, extruded polystyrene pellets (crystal) expanded to from &~out 6.~ to about 12~7 mm. substantially round pellets having a bulk density o~ 12 grams per liter were commi-nuted in a comminuting machine (as described earlier above) equipped with an input ~eeder 10.16 cm. in diameter by 7.62 cm. long and a bottom arcuate screen with holes of 0.1016 mm. diameter.
-11;
~, , .
, ; : . ~ . -The rotor was set to run at 6,ooo r.p.m. and the feeder set to charge the expanded polystyrene bit-pieces at the rate o~ 35.4 liters every 5 minutes (i.e. 425 liters per hour) The starting expanded polystyrens bit-pieces to be introduced into the feeder were wetted with sufficient water substantially completely to cover their outer surfaces. The ~hus wetted expanded polystyrene bit-pieces were charged in~o the feeder continuously at a ra~e o~ ~5.4 liters every 5 minutes, while at the same time water was injected into ~he commi~
nuting chamber through the two 1.6 mm. diameter jet orifices at a rate of 7.57 liters per minute.
m e mixture of the expanded polystyrene micro-bits l~aving the screen bottom of the comminuting chamber was collected in an open tank with a bottom drain plug, wherein the free water settled to the bottom and the polystyrene micro-bits with the bound water held by them (in the proportion of 2 parts of micro-bits to 98 parts of water) due to the entrapped air, rose on top of the free water. The free water was drained off leaving behind a plastic mass of the resulting expanded polysbyrene micro-bits in the water physically bound to them. m e plastic mass weighed 255.15 kilos and contained 5.1 kilos of micro-bits with 250.05 kilos of water bound by them.
27.24 kilos of this plastic mass, placed in a close weave double cotton bag, then were subjected to pressure until 22071 liters o~
water were expressed. The ~emaining 4.08 kilos containing 544 grams of ~ expanded polystyrene micro-bits then were dried in an open dish in an oven maintained at 43.33C.
Micro~bits of any other thermoplastic expanded styrene-polymer or lower polyolefin, each non-brittle in expanded form, or of any flexible foamed (i.e. expanded) polyurethane non-brittle in its foam or expanded fo~m can be prepared by repeating Example A and replacing its starting polystyrene bit-pieces by bit-pieces of any of these other applicable expanded polymers. Thus, each such repeat of Ex~mple A
starting with the micro-bits of each such other applicable expanded polymer is ~o be considered as i~ incorporated herein in full as a separate example, thereby avoiding unnecessarily extending ~his ~ 5 speci~ication.
m e preparation of the gas-vapor treating mats of the in~ention is illustrated by, but not limited to, the following examples:
EXam~le 1 asic Gas-vapor Treatment Mat: Into 15 ,1~9 liters of water charged into a tpaper ma~ing) pulper (of ve~y little greater capacity), there was ~ed by an endless belt conveyor 23.27 kilos (dry basis) o~ polystyrene micro-bi~s (in ~he form of water-bound product containing 8% micro-bits solids). m e pulper contents mixture then was agitated for 3 minutes by its rotor turning at 506 revolutions per minute (r.p.m.) thereby dispersing the micro-bits in the water.
~7hile agitating the mixture, 22.73 kilos o~ sodium hexametaphos-phate were admixed and followed by admixing 3.785 liters of concentrate~
sulfuric acid (98.6,b H2S04). That brought the pH of the batch to 2.5.
m e agitation was stopped while there were added (~rom a number o~ cartons) a total of 113.64 kilos o~ 6.35 millimeters (length) glass fibers (diameter 6.3 microns) Owens-Corning electrical grade DE 636 as thè number o~ ~ilaments per bundle (and bound by a starch, oil and cationic surfactant binder).
m e rotor agitation was resumed and continued for 10 minutes, during the las~ 30 seconds of which 10.25 kilos of (cold) water-swell-able polyvinyl alcohol (98% hydrolyzed) (hereina~ter called PVA) ~ibers were added as binding agent. m e thus completed initial pulper mix was pumped to the beater chest (serving only as holding ~acility to receive amounts o~ pulper mix) and agitated ~here merely ~ufficiently to maintain the insolubles in suspension.
7570 liters of ~rinse) water then were added to the pulper and ;~ ```
~ ;~
agitated to suspend any glass ~ibers and/or micro-bits which settled out and remained behind while the ini~ial pulper mix was being pumped t~ the beater chest. The resulting so-called pulper rinse mix then was pumped to the beater chest and ~here admixed into the initial pulper mix to provide the starting mat~m~king mix containing o.64 solids.
m is starting mat-making mix then was pumped to the machine ohes~
(also a supply holding chest) with its contents maintained under agita-tion also as in the beat~r chest. From this supply chest ~he mat-making mix was fed to ~he furnish box for the Fourdrinier at a ra~te of 4.32 kg.
solids per minute and there combined with clear dilution water at a rate of 6056 LPM tliters per minute).
The resulting uniform web-furnish slurry (as diluted in the furnish bo~ was fed onto the traveling Fourdrinier screen (86 strands 1~, in the machine direction by 60 strands across) moving at a rate of 15.24 meters per minute (i.e. MPM) to enable providing an initial web mat whic after 1ater ~inished drying showed a basis weigh~ o~ 19.1 kg.
The 9.525 m~n. thicls wet mat (on the Fourdrinier) a~ter passing the suction boxes under the leaving end of the Fourdrinier scre~n con-tinued onto an endless belt conveyor (a 112 by 84 mesh screen) also at 15.24 I~PM. Then after about 1.5 meters beyond that end of the Fourdrinier~ the we~ mat (on that conveyor) passed about 10 cm. below a battery (about 60.5 cm. long~ of infrared lamps (52.4 kilowat~s, at ~.8 amperes, 480 volts, single phase 60 cycle) pro~iding at the mat surface a rheostat set temperature o~ possibly 649C. m e exposure o. the wet m~t to that temperature thus for about 2.4 seconds quickly caused solution of the PVA, Ihe partially dry web continued through a tunnel dryer (about 3.67 meters long 'Dy 1 . 83 meters wide) proYiding a temperature of about 121C. and then alternated in sequence o~er one and then under the ~i next of each of a series of six dryer drums (the first drum providing a temperature of 113C. with the temperature increased at each of them that followed with the last drum maintained at 127~). me finally dry mat then passed throu~h a pair of ~ension rollers and onto a wind up drum. m e dry mat web with a smooth surface on each side wound up easily around that drum without a~y tears or wrinklesO
At its basis of 19.1 kilos, the ~inished gas-vapor treating web showed a porosity value (by Gurley porosity meter) of about 602.8 liters per minute (i.e. LPM) per square decimeter (i.e. sq. dcm.) of sur~ace at a tes~ dif~erential air pressure of 2.54 centime~ers of water (gage).
Based on the starting amoun~s of the essential materials, the finished dry gas-vapor treating mat contains about 15.8% of the ex-panded polystyrene micro-bits~ about 77.2~ of glass fibers and about 6.97~' of polyvinyl alcohol binder. The content of thsse essential constituents may be varied in accordance with desired variations in porosity~ gas or vapor ~luid flow rate and density by suitable varia-tions in the constituents content. For example7 the porosity can be decreased by lowering the micro bits content to any le~el do~m to a mini~um of about 2% without corresponding decrease in tensile strength.
Alternatively, the porosity and flow rate can be increased by increasing ~he micro--bits content, as in some formulationst to any level even up to about 50%
Example 1 can be repeated by reducing the ~uantity o~ sulfuric acid in part or as a whole and also by reducing the amount of sodium hexametaphosphate (ordinarily used to e~lance glass fibers dispersion~
in whole or in part in preparing the initial pulper suspension, in ~iew of the indication that the micro-bits appear to enhance dis persion of the solid constituen~s during agitation in the water.
~0 Depending on the anticipated ultimate use o~ the ~as-vapor treating mat its basis weight can be reduced or enlarged by either decreasing or increasing the solids content in the aqueous ~urnisn in the furnish box or increasing or reducing the speed of the Fourdrlnier screen~ m e replacement may be in part or as a whole.
Example 2 - ~
Micro~Bits: Into a 3.5 liter stainless steel beaker containing 3 liters of water, there was dispersed 21.5 grams of (~urniture grade) flexible polyurethane m,icro-bits containing 20% solids (thus 4.3 grams of dry micro-bits and 17.5 cc. of water) by an air driven stirrer.
m en 15 grams OL the same 0.635 cm. length DE 636 glass fib~r las of Example 1) were added and a~itation continued. In the last 10 minutes of an hour of stirring there was admixed 1.375 grams of the PVA tsame as in Example 1).
Six-tenths o~ the resul~ing dispersed slurry then was poured over the hand sheet screen of an ordinary laboratory paper hand sheet former (having a 30.48 cm. high brass tank with a 20.32 cm. square base) and mixed from the top. The water discharge valve was opened with the solids o~ the slurry developing in sheet ~orm on the screen and the water dripping through the scree~ by gra~ity from the increas-ing density slurry. After no further water drained off by gravity, the wet sheet was dried in a drying oven by a hot air stream at 121C.
~lowing through it for 5 minutes. The resulting 12.57 grams dry hand sheet mat showed a tensile strength of 1.41 kilos per cm. and porosity of 579 liters per square decimenter per minute.
Example 2 includes no sodium hexametaphosphate and sulfuric acid because the micro-bits tend to enhance dispersion of the glass fibers which as introduced into the water appear to a large extent in a multitude of bundles of the fibers. Other mats of this invention can be made similarly without these two inorganic substances,from micro-bits o~ the other effective polymers.
....
. . , . . ~
Example 2 was repeated except that during the agitation a~ter admixin~
~he glass fibers, i~stead of PVA there was admixed 60 grams of the cobea~ suspension o~ Example 5 amounting to 1.2 grams of the cobeat solids (composed of beater beaten, interlocked wet lap cotton ~ibers and polystyrene micro-bits). m e preparation o~ the mat then was completed as in EXample 2. m e resulting dry mat showed porosity of 335 1iters per sq~ dcm. per minute, at 0.45 kg. dif~erential pressure (gage), and tensile strength of 0.61 kg. per cm.
EXam le 4 - ample 3 With Pol~y_ ne ~Replacin~ P~o~y~rethane:
EXample 3 was repeated by using polystyrene micro-bits instead-of the polyurethane mlcro-bI~s, and also cobeat as the binder instëad of PVA. The resulting dry web showed tensile streng~ of 0.22 kg.
per cm. and porosity of 5,377 LPM at 0.45 kg. per cm. differential pressure (gage).
m e adsorbent (oonstituent) containing gas-vapor ~iltering or treating mats of this in~ention are illustrated by, but not restricted to, the following:
Example 5 - ctivated Carbon-containing Adsorption Mat: ~a?
Cobeat Suspension PreE~ n: A cobeat suspension (so-called because wet lap cotton ~ibers and micro-bits are beaten together in a beater) was prepared by charging 363.6 kilos (dry basis) of wet lap cotton fibers (as used in paper making, containi~g 1454.4 liters o~ water in ~ the ~ibers) and 181.8 kilos (dry basis) o~ polystyrene micro-bits t6Yo solids with 2848.5 liters of bound water) into 13,354 liters of water in a pulper and agitated ~or 3 minutes (as in Example 1) thereby dis persing the cotton fibers and micro-bits free of clumps and clusters in the water.
That cotton fibers and micro-bits dispersion was pumped to a (paper making) beater having its pressure roll set at 65% o~ maximum and run at 110 r.p.m. for 6 hours (when the freeness starting at 760 .
.
was ~ound to have dropped to 600). The roll setting then was changed to provide more fibrillation and less cutting action, by using only the brush roll pressure with the roll barely contacting the bed. m e desired end occurred in two hou~s whe~ the ~reeness was ~ound reduced to 450. The beater content (now the cobeat suspension) ~as retained in the beater under merely sufficient agitation ~or the dispersion to remain in~c~uspension for later use.
The term ~'freeness~' used hereinabove is a term commonly used concerning the pulp in paper making, and is defined in U.S.
Patent 3,293,114 of December 20, 1966 (Column 3, lines 27-50 as:
"Freeness of pulp is a measure of the rate ~ flow of water through the pulp and is measured in accordance with the - Tappi Standard T 227 m-~8, also referred to as the Canadian Standard Freeness".
The wet làp cotton fibers are those commonly used in writing paper making to provide its cotton rag content. They are prepared for the most part from cotton fabric cuttings and cotton linters which are washed (bleached if necessary) and separated into fibers (as in a hollander) of from about 4.73 mm. to about 1.27 cm. in length, fed to a wet lap machine and from it as a web between pressure rolls and lea~ing as a web about 2.1 mm. thick (containing about 80% moisture) and then lapped up and back over and o~er on a pallet usually to a pile of about 363.8 kilos gross weight.
~ : Into 7570 liters of water in the pulper, there was admixed 136.4 kilos (dry basis) of the polystyrene micro-bits (as the water-bound product containi~g 16% micro bits solids and 715.9 liters of water) and agitated to a uniform dispersion and maintained under merely suf~icient agitation for that until shortly needed.
~ : A ~urnish supply suspension was prepared in a beater chest (i) by feeding into it 30,280 liters of water, (ii) admixing into the water 189.3 liters of the foregoing cobeat sus pension, thus proYiding a diluteA cobeat suspension, (iii) followed by admixing 91 kilos o~ readily wa~er dispersible, se~i -dull, opticzlly whitened polyethylene t~rephthala~e ~ D~e~
: ficially in 1.27 ~m. long ~iber~ o~ 1~5 denier gpu~ by con~entlonal melt process9 ha~ing a special finish compatible with most anionic, cationic or nonionic binders (and providing rapid and excellent dis-persion with a wide ~ariety of rurnish ~ystems ~nd additi~es~, and solution viscosity of 770 ~ 20 of 1/2 gram dissolved in 50 ml. of solvent (by w~ight~ 40 parts to tetrachloroethane and 60 parts phenol) at 25C. (solution ~isoosity is the ~iscosity of the polymer solution divided by the vi cosity of the solYenty with the result minus one multiplied by 1000); mel~ing point 48.67C., non-shrinka31e in boiling water, and elongation at break 45~ (available as TREVIRA 101, product of American Hoechst Corporation, Fibers Di~ision, Spartenburg, South Carolina 29301~the incorporatiQn of polyethylene terephthalate f~s in the suspension requires a relatively low solids content;
(iv) admixing 172~7 ~ilos of finely divided activated carbon (Nuchar S-N
product of ~restvaco Corporation, Covington, Va. 24426); and also (v) admixing the ~oregoing micro-bits suspension containing the 136 4 kilos (dry basis) of polystyrene micro-bits as the water-bound product ~avin~ abou~ 1656 micro-bits solids) thereby adding 716 liters of water to the 7570 liters initially included; and finally (vi) adding 4163.5 liters o~ the cobeat suspension (containing 193.4 kilos of solids) and 15,140 liters of the JUSt below identified glass fibers, micro-bits and binder suspension containing 187.7 kilos o~
suspended solids.
mis ~us-pension was prepared by the proGedure used in (the first 4 paragraphs of) EXample 1 by charging into a pulper 11,354 liters of water, admix-- ing 22.73 kilos (dry basis) of polystyrene micro~bits as the water -bound product (containing 65~ solids and 356 liters of water), dis solving 22.73 ~ilos of sodium hexametaphosphate and 3.8 liters of sul~uric acid (98.6%)9 and admixing 113.64 kilos of the same 6.35 mm.
length glass fibers and 10.23 kilos o~ the same PVA ~ibers. This suspension then was pumped to a beat~r chest.
*Trademark - 19 _ m e pulper then was rinsed by adding 3785 liters of water and agitating the content as in Example 1. The resulting rinse suspen-sion then was admixed with the pulper suspension in the beater chest9 thus providing the glass fibers, micro;;bits and binder suspension, as ~he second member o~ the constituent (vi) of the ~urnish supply suspension.
While maintained under agitation in the beater supply chest, this uniformly admixed furnish supply suspension was fed to the Fourdrinier machine head box at the same rate and admixture with dilution water as in Example 1~ and onto ~he moving FOurd~inier screen. A~ter passing the suction boxes, the resulting wet web continued onto the endless belt conveyor and then was dried by passing in sequence under the battery of infrared lamps through the tunnel dryer and under and oYer the series o~ six dryer d~ums.
The final activated carbon-containing adsorbing mat was uni-form in appearance with a basis weight o~ 15 to 15.45 kg. porosity o~ 353.7 liters per minute per square decimeter, and tensile strength of 1.074 kilos per cm. in the machine direction and 0.895 kilos per cm. in the cro3s direction.
m e polystyrene micro-bits of Examples 1, 4 and 5 can be re-placed in par~ or as ~ ~hole by those of any other of the applicable expanded ~hermoplastic styrene-polymers or lower polyole~ins or of flexible polyurethanes each non-~rittle in expanded form. Thus, each , .
such repeat of Examples 1, 4 and 5 by the just indicated replacement 2~ o~ expanded polystyrene micro-bits is ~o be considered as if occurring herein in full as a complete example, thereby a~oiding making ~his specification prolix. m e lower polyolefins from polyethy~ene to poly-methylpentene include also polypropylene and polybutene.
In any of Examples 1 to 5, and any of t~e ~ust above indicated modifications of any of them, the micro-bits can be provided with any .
--2~
, - :
amount of water held by ~hem ~s well as in the dry state. The micro -bits were provided in these examples as used along with di~ferent amounts ~f water held by them, because o~ their ready availability in that form and their ~hus lower eost.
Similarly, the cotton fibers used in preparing the cobeat were provided in their fo~ as wet lap cottoa~ fibers~ ordinarily contain ing about 80% of water, because of the economy in doing sO. Howe~er, that does not preclude using ~hese cot~on fibers in t~e dry state ~hen thus aYailable or desired ~or any particula~ reason.
The West~aco's NUCHAR~ -N acti~ated carbon in EXample 5 can be replaced by any other Westvaco actiYated carbon. For exa~ple, if the mat is to be used ~or adsorbing pnenol, WestYacO~s NUCHAR N A ~yield-ing an acid wash water when washed in wa~er) would be beneficial be-cause that acid grade mani~ests higher adsorption o~ phenol~
Either of these two grades of activat~d carbon ~an be replaced by any of the others available, for examp~e, DARCO now available from I.C.I. (U.S.A~) Ltd., and the NORIT product of American Norit Co. ~ne Bar~eby-Cheney activated carbon from pecan nut shells is highly ef~ec-ti~e, ~or.example, in the adsorption o~ sulfur dioxide from a gas stream, for which it showed a very much greater adsorption capacity tha an activated carbon from another source. Thus, Example 5 is to be considered as if present~d written out in full with its activated carbon replaced by the ~a~neby-Cheney product.
The polyester of Example 5 can be replaced by any oth~r fiber -forming terephthalate polyester, f ~ example, the FORTREL poly-ethylene terephthalate and th~ KOD~ ~imethyl 1.4-cYclo~exane di~
methanol. Example 5 and the thus resulting examples derived from it are to be considered as if presented as written out in full with the polyester separately respectively replaced by each one of these other polyesters. ~ny of them can be used in any of the available 1.5 and 3 denier diameters.
~21~
The mats of this in~ention are ef~ec~ive for removal and/or recovery o~ various gases or ~apors, either inorganic or organic, for example, sulf~r dioxide, chlorinated alkanes such as carbon tetrachloride and other chlorinated alkanes~ and benzene and phenol~
While the in~ention has been e~plained by detailed description of certain specific embodiments of it, it is understood t~at various substitutions or modifica~ions ca~ be made in any o~ them within the scope o~ the appended claims which are i~tended to co~er also equi-~alents of these embodiments.
Claims (22)
CLAIMED ARE DEFINED AS FOLLOWS:
1. A gas-vapor treating mat which comprises glass fibers from about 6.35 millimeters long to below a length at which said fibers are prone to roping, and from about 3 to 12 microns in diameter, intermixed with micro-bits of any of an expanded, thermoplastic styrene polymer, a lower polyolefin, which is the polymer of an ethylenically unsaturated hydrocarbon monomer having from 2 to 6 carbon atoms, and a flexible foamed polyurethane, each said polymer being non-brittle in its initial expanded form, said intermixed glass fibers and polymer micro-bits being permeable to a gaseous and/or vaporous fluid stream and held together in sheet or elongated web form by a binding agent selected from (a) a compatible organic binder insoluble in cold water and soluble in hot water and inert to the glass fibers, the micro-bits and any other mat constituent as well as any gas or vapor or entrained droplets or aerosols and fine particles that are to contact the mat, or (b) a cobeat of cotton fibers and any of said micro-bits, or a mixture of binding agents (a) and (b), said binding agent being distributed throughout the micro-bits and glass fibers so as to hold said micro-bits and glass fibers together in said sheet or elongated web form without destroying the permeability thereof; the components of said mat being in the following proportions:
(i) said micro-bits comprising from about 2 to about 50% by weight of the finished mat;
(ii) said binding agent comprising from about 2%
to about 10% by weight of the finished mat when the organic binder is used, and from about 5.8% to about 11% by weight of the finished mat when the cobeat binder is used, and (iii) said glass fibers making up the balance of the finished mat;
said finished mat having a tensile strength from about 0.9 to about 5.3 kilograms per centimeter.
(i) said micro-bits comprising from about 2 to about 50% by weight of the finished mat;
(ii) said binding agent comprising from about 2%
to about 10% by weight of the finished mat when the organic binder is used, and from about 5.8% to about 11% by weight of the finished mat when the cobeat binder is used, and (iii) said glass fibers making up the balance of the finished mat;
said finished mat having a tensile strength from about 0.9 to about 5.3 kilograms per centimeter.
2. A gas-vapor treating mat as claimed in claim 1, wherein the micro-bits are those of a styrene polymer.
3. A gas-vapor treating mat as claim in claim 1 or 2, wherein the micro-bits are of polystyrene.
4. A gas-vapor treating mat as claimed in claim 1, wherein the micro-bits are those of a polyurethane.
5. A gas-vapor treating mat as claimed in claim 1, wherein the micro-bits are those of a lower polyolefin.
6. A gas-vapor treating mat as claimed in claim 5, wherein the polyolefin is polyethylene.
7. A gas-vapor treating mat as claimed in claim 1, wherein the binding agent is polyvinyl alcohol which is at least 98% hydrolyzed.
8. A gas-vapor treating mat as claimed in claim 7, wherein the micro-bits are those of a styrene polymer.
9. A gas-vapor treating mat as claimed in claim 8, wherein the micro-bits are of polystyrene.
10. A gas vapor treating mat as claimed in claim 7, wherein the micro-bits are of a polyurethane.
11. A gas-vapor treating mat as claimed in claim 7, wherein the micro-bits are those of a lower polyolefin.
12. A gas-vapor treating mat as claimed in claim 11, wherein the micro-bits are of polyethylene.
13. A gas-vapor treating mat as claimed in claim 1, wherein the binding agent is a cobeat of the cotton fibers and any of the mioro-bits.
14. A gas-vapor treating mat as claimed in claim 13, wherein the micro-bits are those of a styrene polymer.
15. A gas-vapor treating mat as claimed in claim 14, wherein the micro-bits are of polystyrene.
16. A gas-vapor treating mat as olaimed in claim 13, wherein the micro-bits are of a polyurethane.
17. A gas-vapor treating mat as claimed in claim 13, wherein the micro-bits are those of a lower polyolefin.
18. A fas-vapor treating mat as claimed in claim 17, wherein the micro-bits are of polyethylene.
19. A gas-vapor treating mat as claimed in claim 7, which contains 77.2% of glass fibers, 15.8% of polystyrene mioro-bits and about 6.97% of the polyvinyl alcohol, and wherein the glass fibers are about 6.35 millimeters long and 6.3 microns in diameter.
20. A gas-vapor treating mat as claimed in claim 1, which in addition to its content of glass fibers, the micro-bits and the binding agent, contains, of the overall content of the mat, intermixed (i) activated carbon in an amount from about 2% to that amount beyond which more than insignificant dusting of carbon from the mat would occur, (ii) a fiber-forming terephthalate polyester in an amount from about 5 to about 10%, and (iii) the cobeat in an amount of from about 2 to about 30% as the binding agent.
21. A gas-vapor treating mat as claimed in claim 20, wherein the micro-bits are those of any of a styrene polymer, a polyurethane and a lower polyolefin.
22. A gas-vapor treating mat as claimed in claim 21, wherein the polyester is any of (a') polyethylene terephthalate and (b') the dimethyl terephthalate of 1,4-cyclohexane dimethanol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US87719078A | 1978-02-13 | 1978-02-13 | |
| US877,190 | 1978-02-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1124659A true CA1124659A (en) | 1982-06-01 |
Family
ID=25369443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA321,284A Expired CA1124659A (en) | 1978-02-13 | 1979-02-12 | Porous media to separate gases or vapors and coalesce entrained droplets |
Country Status (19)
| Country | Link |
|---|---|
| JP (1) | JPS54119177A (en) |
| AT (1) | AT372875B (en) |
| AU (1) | AU530309B2 (en) |
| BE (1) | BE874060A (en) |
| BR (1) | BR7900874A (en) |
| CA (1) | CA1124659A (en) |
| CH (1) | CH650699A5 (en) |
| DE (1) | DE2905212A1 (en) |
| DK (1) | DK55179A (en) |
| FI (1) | FI69762C (en) |
| FR (1) | FR2422429A1 (en) |
| GB (2) | GB2015056B (en) |
| IL (1) | IL56637A (en) |
| IT (1) | IT1116824B (en) |
| MX (1) | MX151433A (en) |
| NL (1) | NL7901096A (en) |
| NO (1) | NO152238C (en) |
| SE (1) | SE434015B (en) |
| ZA (1) | ZA79647B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0060677A1 (en) * | 1981-03-13 | 1982-09-22 | AMSTED Industries Incorporated | Composite filter media |
| DE3126645A1 (en) * | 1981-07-07 | 1983-01-20 | Collo Gmbh, 5303 Bornheim | FILTER MAT, ESPECIALLY FOR KITCHEN HOODS AND THE LIKE AND METHOD FOR THEIR PRODUCTION |
| CN105363278A (en) * | 2015-12-15 | 2016-03-02 | 常熟市一心无纺制品有限公司 | Glue-sprayed type non-woven fabric |
| BR112020025740B1 (en) | 2020-01-15 | 2022-06-14 | Ihi Transport Machinery Co., Ltd. | RAIN PROTECTION DEVICE FOR A NOZZLE |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1211702A (en) * | 1957-10-07 | 1960-03-17 | American Air Filter Co | Improvements to filter media |
| US3228825A (en) * | 1961-08-15 | 1966-01-11 | Owens Corning Fiberglass Corp | Method of forming fibrous structures from a combination of glass fibers and cellulosic fibers |
| US3353682A (en) * | 1966-02-28 | 1967-11-21 | Pall Corp | Fluid-permeable fibrous multilayer materials and process of making the same |
| DE1957763C3 (en) * | 1969-11-17 | 1979-03-15 | H.F. & Ph.F. Reemtsma, 2000 Hamburg | Tobacco smoke filter H.F. & Ph.F. Reemtsma, 2000 Ham¬ |
| US3749638A (en) * | 1971-01-11 | 1973-07-31 | Owens Corning Fiberglass Corp | Formation of non-woven structures from fibrous glass dispersion |
| CS159406B1 (en) * | 1971-09-03 | 1975-01-31 | ||
| US4084949A (en) * | 1975-11-06 | 1978-04-18 | The Dexter Corporation | Surgical face mask filtering medium |
-
1979
- 1979-02-07 IT IT47922/79A patent/IT1116824B/en active
- 1979-02-09 GB GB7904618A patent/GB2015056B/en not_active Expired
- 1979-02-09 DK DK55179A patent/DK55179A/en not_active Application Discontinuation
- 1979-02-09 BE BE0/193370A patent/BE874060A/en not_active IP Right Cessation
- 1979-02-09 IL IL56637A patent/IL56637A/en unknown
- 1979-02-12 FR FR7903535A patent/FR2422429A1/en not_active Withdrawn
- 1979-02-12 MX MX176571A patent/MX151433A/en unknown
- 1979-02-12 NL NL7901096A patent/NL7901096A/en not_active Application Discontinuation
- 1979-02-12 NO NO790447A patent/NO152238C/en unknown
- 1979-02-12 CH CH1359/79A patent/CH650699A5/en not_active IP Right Cessation
- 1979-02-12 CA CA321,284A patent/CA1124659A/en not_active Expired
- 1979-02-12 SE SE7901213A patent/SE434015B/en unknown
- 1979-02-12 AT AT0105079A patent/AT372875B/en not_active IP Right Cessation
- 1979-02-12 DE DE19792905212 patent/DE2905212A1/en not_active Withdrawn
- 1979-02-13 ZA ZA79647A patent/ZA79647B/en unknown
- 1979-02-13 BR BR7900874A patent/BR7900874A/en unknown
- 1979-02-13 AU AU44179/79A patent/AU530309B2/en not_active Ceased
- 1979-02-13 JP JP1439979A patent/JPS54119177A/en active Pending
- 1979-02-13 FI FI790475A patent/FI69762C/en not_active IP Right Cessation
-
1982
- 1982-08-09 GB GB08222912A patent/GB2105759B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| IL56637A0 (en) | 1979-05-31 |
| GB2105759B (en) | 1983-08-03 |
| FR2422429A1 (en) | 1979-11-09 |
| DE2905212A1 (en) | 1979-08-16 |
| ATA105079A (en) | 1983-04-15 |
| IL56637A (en) | 1982-02-28 |
| AU530309B2 (en) | 1983-07-14 |
| GB2015056B (en) | 1983-03-30 |
| FI69762B (en) | 1985-12-31 |
| NO152238C (en) | 1985-08-28 |
| NL7901096A (en) | 1979-08-15 |
| GB2105759A (en) | 1983-03-30 |
| BR7900874A (en) | 1979-09-11 |
| SE434015B (en) | 1984-07-02 |
| ZA79647B (en) | 1980-02-27 |
| IT1116824B (en) | 1986-02-10 |
| IT7947922A0 (en) | 1979-02-07 |
| GB2015056A (en) | 1979-09-05 |
| BE874060A (en) | 1979-08-09 |
| NO790447L (en) | 1979-08-14 |
| JPS54119177A (en) | 1979-09-14 |
| FI69762C (en) | 1986-05-26 |
| FI790475A (en) | 1979-08-14 |
| DK55179A (en) | 1979-08-14 |
| AU4417979A (en) | 1979-10-18 |
| SE7901213L (en) | 1979-08-14 |
| AT372875B (en) | 1983-11-25 |
| CH650699A5 (en) | 1985-08-15 |
| MX151433A (en) | 1984-11-21 |
| NO152238B (en) | 1985-05-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4239516A (en) | Porous media to separate gases liquid droplets and/or solid particles from gases or vapors and coalesce entrained droplets | |
| US4344775A (en) | Method for separating gases liquid droplets and/or solid particles from gases or vapors | |
| USRE31849E (en) | Porous media to separate gases liquid droplets and/or solid particles from gases or vapors and coalesce entrained droplets | |
| CA1134755A (en) | Adsorption and filtration mat for liquids | |
| Feng et al. | Preparation of a rice straw-based green separation layer for efficient and persistent oil-in-water emulsion separation | |
| US4293378A (en) | Enhanced wet strength filter mats to separate particulates from fluids and/or coalesce entrained droplets from gases | |
| US3573158A (en) | Microporous fibrous sheets useful for filters and apparatus and method of forming the same | |
| US2626213A (en) | Asbestos dispersions and method of forming same | |
| US3353682A (en) | Fluid-permeable fibrous multilayer materials and process of making the same | |
| US4286977A (en) | High efficiency particulate air filter | |
| Yu et al. | Highly compressible and durable superhydrophobic cellulose aerogels for oil/water emulsion separation with high flux | |
| US20110009259A1 (en) | Cellulose powder and processes for its production | |
| US4569756A (en) | Water treatment system | |
| US2797163A (en) | Method of making filter media | |
| US4454044A (en) | Water treatment process | |
| CA1124659A (en) | Porous media to separate gases or vapors and coalesce entrained droplets | |
| CN101479427A (en) | Process for loading a fibrous suspension with filler | |
| JPH02298394A (en) | Method for removing petroleum contaminated substances and articles therefor | |
| CN104470615B (en) | Filtering material and manufacture method thereof for filter | |
| DE2543007A1 (en) | SEWAGE TREATMENT MATERIAL | |
| Bin Mukhlish et al. | Flexible alumina-silica nanofibrous membrane and its high adaptability in reactive red-120 dye removal from water | |
| US11807554B2 (en) | Method for removing organic pollutants from contaminated water using polystyrene-carbon nanofiber composition made from post-consumer waste | |
| US4251320A (en) | Method of producing a mineral fiber product | |
| US2614655A (en) | Filter material | |
| US5141643A (en) | Filter material formed by fibride particles |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |