U.S. patent number RE31,849 [Application Number 06/447,784] was granted by the patent office on 1985-03-19 for porous media to separate gases liquid droplets and/or solid particles from gases or vapors and coalesce entrained droplets.
Invention is credited to Max Klein.
United States Patent |
RE31,849 |
Klein |
March 19, 1985 |
**Please see images for:
( Certificate of Correction ) ** |
Porous media to separate gases liquid droplets and/or solid
particles from gases or vapors and coalesce entrained droplets
Abstract
Gas-vapor treating and filter mats composed of glass fibers
intermixed with micro-bits of any of an expanded thermoplastic
styrene-polymer or expanded thermoplastic lower polyolefin or
flexible foam polyurethane and a suitable organic bonding agent,
which mat may contain any of fibers of a fiber-forming
terephthalate polyester, activated carbon, and gas-vapor adsorbent
crystalline zeolite molecular sieve particles.
Inventors: |
Klein; Max (Shrewsbury,
NJ) |
Family
ID: |
26691164 |
Appl.
No.: |
06/447,784 |
Filed: |
December 8, 1982 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
018472 |
Mar 8, 1979 |
04239516 |
Dec 16, 1980 |
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Current U.S.
Class: |
502/62; 55/524;
55/527; 55/528 |
Current CPC
Class: |
B01D
39/14 (20130101); B01D 39/16 (20130101); B01D
39/2017 (20130101); B01J 20/28033 (20130101); B01J
20/28028 (20130101); B01J 20/2803 (20130101); B01J
20/28004 (20130101) |
Current International
Class: |
B01D
39/16 (20060101); B01D 39/20 (20060101); B01D
39/14 (20060101); B01J 20/28 (20060101); B01D
039/16 () |
Field of
Search: |
;55/522,524,528,389
;210/502-510 ;162/145,146 ;131/202,341,332,342 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1957763 |
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May 1971 |
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DE |
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6801723 |
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Aug 1968 |
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NL |
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868651 |
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May 1961 |
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GB |
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1070737 |
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Jun 1967 |
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GB |
|
1118221 |
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Jun 1968 |
|
GB |
|
1364762 |
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Aug 1974 |
|
GB |
|
Primary Examiner: Nozick; Bernard
Attorney, Agent or Firm: Dann, Dorfman, Herrell and
Skillman
Parent Case Text
BRIEF DESCRIPTION OF THE INVENTION
This application is a continuation-in-part of copending application
Ser. No. 877,190 filed Feb. 13, 1978, now abandoned.
Claims
What is claimed is:
1. A gas-vapor treating mat which comprises (a) glass fibers, of
about 6.3 millimeters long and below a length at which they are
prone to roping and from about 3 to about 12 microns in diameter,
intermixed .[.in the range of from about 4 to about 45 parts.].
with (b) from about 5 to about 50.Iadd.% .Iaddend..[.parts.]. of
the micro-bits of .[.any of an expanded, thermoplastic
styrene-polymer, an expanded lower polyolefin selected from
polyethylene to poly-methylpentene, and.]. and a flexible foamed
polyurethane .Iadd.which are in the form of tripodal particles
having generally uneven length legs, said particles comprising
broken and inter-connected strand portions from adjacent cells of
said flexible foamed polyurethane, said strand portions being
substantially free of intact cell windows and having hook-like
projections, indentations and flutes extending therefrom, said
hook-like projections, indentations and flutes having been formed
by the destruction of the cell windows of said flexible
foam.Iaddend., .[.each said polymer being non-brittle in its
initial expanded form;.]. said intermixed glass fibers and polymer
micro-bits being held together in sheet or elongated web form and
permeable to any of a gaseous and vaporous fluid stream by (c) a
binding agent distributed throughout the intermixture of the glass
fibers and micro-bits in an amount and manner sufficient to hold
them together in the herein noted form and without destroying their
permeability, which agent is selected from (i) 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 to any gas or vapor or entrained droplets or aerosols
and fine particles that are to contact the mat and (ii) a cobeat of
cotton fibers and any of the micro-bits; whereby the mat has
tensile strength from about 0.2 to about 5.3 kilograms per
centimeter.
2. A gas-vapor treating mat as claimed in claim .[.1,.]. .Iadd.35
.Iaddend.wherein the micro-bits are those of a styrene-polymer.
3. A gas-vapor treating mat as claimed in claim 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,.]. .Iadd.35
.Iaddend.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 .[.any of claims 1 to 5 or
6.]. .Iadd.claim 1 or 34.Iaddend., wherein the binding agent is
polyvinyl alcohol at least
98% hydrolyzed. 8. A gas-vapor treating mat as claimed in .[.any of
claims 1 to 5 or 6.]. .Iadd.claim 1 or 34 .Iaddend.wherein the
binding agent is a
cobeat of the cotton fibers and .[.any of.]. the micro-bits. 9. A
gas-vapor treating mat as claimed in claim .[.7,.]. .Iadd.35,
.Iaddend.which contains by weight 77.2% of glass fibers, 15.8% of
polystyrene micro-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. 10. 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 by weight of the overall content of
the mat, intermixed therein (i) a particulate additive selected
from any of activated carbon and gas-vapor adsorbent crystalline
zeolite molecular sieve particles, and in an amount from about 2%
to that amount beyond which more than insignificant dusting of
carbon or molecular sieve particles from the mat would occur, (ii)
a fiber-forming terephthalate polyester in a 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. 11. A gas-vapor treating mat as
claimed in
claim 10, wherein the particulate additive is activated carbon. 12.
A gas-vapor treating mat as claimed in claim 10, wherein the
particulate additive is the crystalline zeolite molecular sieve
particles. .[.13. A gas-vapor treating mat as claimed in claim 11
or 12, wherein the micro-bits are those of any of an expanded
styrene-polymer, a flexible
polyurethane, and an expanded lower polyolefin..]. 14. A gas-vapor
treating mat as claimed in claim .[.13,.]. .Iadd.10,
.Iaddend.wherein the polyester is any of (a') polyethylene
terephthalate and (b') the dimethyl
terephthalate of 1,4-cyclohexane dimethanol. 15. A gas-vapor
treating mat as claimed in claim 10, wherein the fiber-forming
polyester is the polyethylene terephthalate polyester which is
readily water dispersible, semi-dull, optically whitened, in 1.27
cm. long fibers of 1.5 denier, having a finish compatible with most
anionic, cationic or nonionic binders and providing rapid and
excellent dispersion with a wide variety of furnish systems and
additives, and a solution viscosity at 25.degree. C. of 770.+-.20
of 1/2 gram when dissolved in 50 ml. of a solvent consisting by
weight of 40 parts of tetrachloroethane and 60 parts of phenol; a
melting point of 48.67.degree. C., being non-shrinkable in boiling
water,
and having elongation of 45% at break. .Iadd.16. A fluid-permeable
gas-vapor treating mat which comprises a sheet or elongated web
formed from a mixture of:
(a) glass fibers from 6.35 millimeters long to below a length at
which said fibers are prone to roping, and from 3 to 12 microns in
diameter;
(b) micro-bits of an expanded, thermoplastic polymer which is
non-brittle in its initial expanded form, and is selected from a
styrene polymer, and a polyolefin, selected from polyethylene,
polypropylene, polybutene and polymethylpentene, said polymer
micro-bits being from about 40 to about 325 microns long and from
about 20 to about 325 microns wide, from substantially completely
to entirely completely free of intact cells of the expanded polymer
from which said micro-bits were produced, substantially without any
uniformity in outline of the individual micro-bits particles, and
having density from about 85 percent of, to about substantially the
same as, the specific unexpanded polymer from which there was
provided said expanded polymer from which said micro-bits are
produced, and said micro-bits comprising from about 2 to about 50%
by weight of the finished mat; and
(c) 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, or (b)
a cobeat of cotton fibers, and any of said micro-bits, said binding
agent being distributed throughout said mat, and comprising from
about 2% to about 10% by weight of the finished mat when the
organic binder (a) is used, or from about 5.8% to about 11% by
weight of the finished mat when the cobeat (b) is
used. .Iaddend. .Iadd.17. A gas-vapor treating mat as claimed in
claim 16, wherein the micro-bits are those of a styrene-polymer.
.Iaddend. .Iadd.18. A gas-vapor treating mat as claimed in claim
17, wherein the styrene-polymer is polystyrene. .Iaddend. .Iadd.19.
A gas-vapor treating mat as claimed in claim 16, wherein the
micro-bits are those of a lower polyolefin. .Iaddend. .Iadd.20. A
gas-vapor treating mat as claimed in claim 19, wherein the
polyolefin is polyethylene. .Iaddend. .Iadd.21. A fluid-permeable
gas-vapor treating mat which comprises a sheet or elongated web
formed from a mixture of:
(a) glass fibers from 6.35 millimeters long to below a length at
which said fibers are prone to roping, and from 3 to 12 microns in
diameter;
(b) micro-bits of a flexible foamed polyurethane which are in the
form of tripodal particles having generally uneven length legs,
said particles comprising broken and inter-connected strand
portions from adjacent cells of said flexible foamed polyurethane,
said strand portions being substantially free of intact cell
windows and having hook-like projections, indentations and flutes
extending therefrom, said hook-like projections, indentations and
flutes having been formed by the destruction of the cell windows of
said flexible foam, said micro-bits comprising from about 2 to
about 50% by weight of the finished mat; and
(c) 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, or (b)
a cobeat of cotton fibers, and any of said micro-bits, said binding
agent being distributed throughout said mat, and comprising from
about 2% to about 10% by weight of the finished mat when the
organic binder (a) is used, or from about 5.8% to about 11% by
weight of the finished mat when the cobeat (b) is used. .Iaddend.
.Iadd.22. A gas-vapor treating mat as claimed in claim 21
or 16, wherein the organic binder (a) is employed. .Iaddend.
.Iadd.23. A gas-vapor treating mat as claimed in claim 22, wherein
the organic binder is polyvinyl alcohol at least 98% hydrolyzed.
.Iaddend. .Iadd.24. The gas-vapor treating mat as claimed in claim
23 wherein the micro-bits are polystyrene. .Iaddend. .Iadd.25. The
gas-vapor treating mat as claimed in claim 23 wherein the
micro-bits are polyethylene. .Iadd.26. A gas-vapor treating mat as
claimed in claim 24, which contains 77.2% of glass fibers, 15.8% of
polystyrene micro-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. .Iaddend. .Iadd.27. A gas-vapor treating
mat as claimed in claim 22 which also includes:
(i) a particulate additive selected from finely divided activated
carbon or gas-vapor adsorbent crystalline zeolite molecular sieve
particles, in an amount from about 2% by weight to below that at
which more than insignificant dusting of the particulate additive
from the finished mat would occur,
(ii) a fiber-forming terephthalate polyester in an amount of from
about 2% to about 12.2% by weight of the finished mat, and
(iii) cobeat in an amount from about 2 to about 30% by weight of
the
finished mat. .Iaddend. .Iadd.28. The gas-vapor treating mat, as
claimed in claim 27, wherein said particulate additive is activated
carbon and comprises no more than 50% by weight of said finished
mat. .Iaddend. .Iadd.29. The gas-vapor treating mat, as claimed in
claim 27, wherein said particulate additive is gas-vapor adsorbent
crystalline zeolite molecular sieve particles, and comprises no
more than 75% by weight of said finished mat. .Iaddend. .Iadd.30. A
gas-vapor treating mat as claimed in claim 27, wherein the
polyester is polyethylene terephthalate. .Iaddend. .Iadd.31. A
gas-vapor treating mat as claimed in claim 30, wherein the
polyethylene terephthalate polyester is in the form of readily
water dispersible, semi-dull, optically whitened, fibers having a
finish compatible with most anionic, cationic or nonionic binders
and providing rapid and excellent dispersions with a wide variety
of furnish systems and additives, and a solution viscosity at
25.degree. C. of 770+ 20 of 1/2 gram when dissolved in 50 ml. of a
solvent consisting by weight of 40 parts of tetrachloroethane and
60 parts of phenol; a melting point of 48.67.degree. C., being
non-shrinkable in boiling water, and having elongation of 45%
at
break. .Iaddend. .Iadd.32. A gas-vapor treating mat as claimed in
claim 21 or 16, wherein the cobeat binder (b) is employed.
.Iaddend. .Iadd.33. The gas-vapor treating mat as claimed in claim
24, wherein the cobeat binder comprises cotton fibers, prepared by
wet lapping, and polystyrene
micro-bits. .Iaddend. .Iadd.34. A gas-vapor treating mat which
comprises (a) glass fibers, of about 6.3 millimeters long and below
a length at which they are prone to roping and from about 3 to
about 12 microns in diameter, intermixed with (b) from about 5 to
about 50% of micro-bits of thermoplastic styrene-polymer, or an
expanded lower polyolefin selected from polyethylene to
poly-methylpentene, each said polymer being non-brittle in its
initial expanded form; said polymer micro-bits being from about 40
to about 325 microns long and from about 20 to about 325 microns
wide, from substantially completely to entirely completely free of
intact cells of the expanded polymer from which said micro-bits are
produced, substantially without any uniformity in outline of the
individual micro-bits particles, and having density from about 85
percent of, to about substantially the same as, the specific
unexpanded polymer from which there was provided said expanded
polymer from which said micro-bits are produced, said intermixed
glass fibers and polymer micro-bits being held together in sheet or
elongated web form and permeable to any of a gaseous and vaporous
fluid stream by (c) a binding agent distributed throughout the
intermixture of the glass fibers and micro-bits in an amount and
manner sufficient to hold them together in the herein noted form
and without destroying their permeability, which agent is selected
from (1) 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 to any gas or vapor or
entrained droplets or aerosols and fine particles that are to
contact the mat and (ii) a cobeat of cotton fibers and any of the
micro-bits; whereby the mat has tensile strength from about 0.2 to
about 5.3 kilograms per centimeter. .Iaddend.
Description
This invention is that of (a) porous media, briefly called
gas-vapor mats or gas-vapor filtering or treating mats, having 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, and (b) the preparation of
these mats.
The gas-vapor treating mats of the invention consist basically of
(a) .[.a major portion of.]. .Iadd.an intimate mixture of
.Iaddend.very small (e.g. average 6.3 microns) diameter glass
fibers .[.composed of a plurality of filaments and of short length
about 0.635 cm. long, and intermixed therewith.]. .Iadd.the length
of which are at least about 6.3 millimeters and below the length at
which the fibers are prone to roping, .Iaddend.(b) .[.a minor
amount of so-called.]. micro-bits of (i) an expanded thermoplastic
styrene-polymer and/or expanded lower polyolefin and/or (ii) a
flexible foamed polyurethane, each of the members (i) and (ii)
being non-brittle in expanded form, and (c) a .[.still more.].
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 (as described further
below) of wet lap cotton fibers and micro-bits. A gas separation
embodiment of these mats also includes polyester fibers and
activated carbon. The activated carbon can be replaced as a whole
or, under some circumstances, in part by gas-vapor adsorbent,
zeolite molecular sieve particles.
BACKGROUND OF THE INVENTION
A web of merely glass fibers such as the Owens-Corning DE 636
(described in Example 1 below) bound with polyvinyl alcohol (98%
hydrolyzed) was made but its use had been rather restricted. For
example, it has been used as a battery plate separator and as the
base for roof covering to be coated over with tar. However, no such
web of glass fiber and polyvinyl alcohol (i.e. called PVA) has been
known for use in any such treatment of fluids as described
above.
For many years various industries have been concerned with
troublesome solid particles of fine droplets of liquids or harmful
gases released into working areas and often passing through vents
or smoke stacks into the outside atmosphere, thus provoking
bothersome evnironmental problems. In some cases, it has been
merely dust particles from working with inorganic materials such as
recovering minerals from ores or grinding and polishing
operations.
In other cases also involved are liquid droplets entrained from
chemical operations such as electroplating, spray coating of one
kind or another or production of certain synthetic resins. In still
other situations it may be harmful gases, for example, sulfur
dioxide carried into the atmosphere as from burning of high sulfur
content fuel oils or bituminous coals. Production of a
polyphenylene oxide-polystyrene alloy polymer involves release in
part of resin fines or pellets, dust particles and of oily
plasticizer 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 fibers held
together by a phenol formaldehyde resin binder, or (ii) glass wool
air filters in window openings or other outlets. However, 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. Then also some of these mats, among other shortcomings,
have an undesirably limited tensile strength resulting in too
frequent 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 overcome by the gas-vapor filter of
treating mats of the invention. Then too, these mats of the
invention show enhanced porosity and tensile strength over the
above described glass fibers and PVA webs used as battery
separators and in roof covering sheets.
GENERAL DESCRIPTION OF THE INVENTION
Considered broadly, the gas-vapor treating mats of the invention
comprise glass fibers (usually composed of a plurality of
filaments) varying in diameter from about 3 to about 12 microns,
generally more readily applicable as of about 6.3 microns, and more
often selected as about .[.0.635 cm. (i.e. centimeter).].
.Iadd.6.35 mm. .Iaddend.long, and intermixed with micro-bits of any
of an expanded, thermoplastic styrene-polymer, as expanded lower
polyolefin .[.from polyethylene to poly-methylpentene.].
.Iadd.which is the polymer of an ethylenically unsaturated
hydrocarbon monomer having from 2 to 6 carbon atoms.Iaddend., and a
flexible foamed polyurethane, each said polymer being non-brittle
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 80.degree. C. as for PVA) and inert to the
micro-bits, the glass fiber and any other mat constituent as well
as the gases (including 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 Example 5).
The micro-bits can amount to from about 5 to about 50% of the mat,
and beneficially from about 10 to about 35%, and advantageously
from about 15 to about 25%; .[.and.]. the compatible organic
chemical binder .Iadd.may be .Iaddend.present at from about 2% to
about 10% and beneficially at from about 5 to about 8%, or the
cobeat of cotton fibers and micro-bits .[.being.]. .Iadd.may
constitute .Iaddend.from 5.8 to about 11% .Iadd.of the
mat.Iaddend.; and .[.with.]. the glass fibers .[.present in an
amount sufficient to.]. to make up the .[.total of the 100%
content.]..Iadd.remainder of the mat.Iaddend.. The tensile strength
of the mats varies from about .[.0.9.]. .Iadd.0.2 .Iaddend.to about
5.34 kg. per cm. and the porosity varies from about 152 to 914
liters per sq. dcm. (i.e. square decimeter) per minute at 2.54 cm.
(H.sub.2 O).
The micro-bits component of the gas-vapor treating mats of the
invention are micro-bits of any of an expanded, thermoplastic
styrene-polymer or lower polyolefin, non-brittle in expanded form,
or of a flexible foamed polyurethane likewise non-brittle in
expanded form. These micro-bits of an expanded, thermoplastic
styrene-polymer or lower polyolefin are more fully described (as in
my copending United States of America patent application Ser. No.
833,644 filed Sept. 15, 1977.Iadd., now U.S. Pat. No.
4,207,378.Iaddend.) as an expanded, thermoplastic, non-brittle in
expanded form polymer selected from a styrene-polymer and a lower
polyolefin from polyethylene to poly-methylpentene, and
characterized .[.by being in the form of micro-bits and.]. .Iadd.as
being, .Iaddend.(a) from about 40 to about 325 microns long and
from about 20 to about 325 microns wide, (b) from substantially
completely to entirely completely free of intact cells of the
expanded polymer bit-pieces from which they were produced, (c)
substantially without any uniformity in outline of the individual
micro-bits particles, and (d) in density from about 85 percent of,
to about substantially the same as, the specific unexpanded polymer
from which there was provided the aforesaid expanded polymer.
These micro-bits of an expanded, thermoplastic styrene-polymer or a
lower polyolefin are produced from so-called bit-pieces of any of
the expanded thermoplastic, non-brittle in expanded form
styrene-polymers or lower polyolefins as starting material. By
"bit-pieces" is meant any of the discrete free-flowing forms of any
of these styrene-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-polystrene.]. .Iadd.polyethylene-polystyrene
.Iaddend.alloy, (ii) the various sizes of styrene-polymer beads
obtained from suspension polymerization or otherwise as by molding
the particles obtained by disintegrating any of these different
polymer forms, (iii) the so-called "grind" including the coarsely
ground molded polymer or waste or other scrap such polymer of
various sizes e.g. 3.175 millimeter (i.e. .[.ml..].
.Iadd.mm..Iaddend.) thick, 6.35 .[.ml..]. .Iadd.mm. .Iaddend.wide,
and 9.535 .[.ml..]. .Iadd.mm. .Iaddend.long, and (iv) any other
small sized shapes of any of them.
The preparation and properties of flexible polyurethane foams are
described, for example, in the "Handbook of Foamed Plastics",
Bender, Rene J., Section X, pp. 173-236, Lake Publishing
Corporation, Libertyville, Ill., U.S.A. (1955), "Polyurethanes:
Chemistry and Technology", Saunders & Frisch, Chapter VII, Part
II, Interscience Publishers, New York, N.Y. U.S.A. (1964), and "The
Development and Use of Polyurethane Foams", Doyle, E. N., pp.
233-256, McGraw Hill Book Company, New York, N.Y., U.S.A.
(1971).
The flexible polyurethane foams useful to provide foamed
polyurethane micro-bits preferably should be no greater than 95.3
gm. (i.e. grams) per liter in density, beneficially ranging from
about 47.7 to about 15.9 gm. per liter, and show excellent recovery
after 75% deflection with approximately less than 1% loss in height
(as determined by American Society of Testing Materials
D-1564-64T).
The flexible foam polyurethanes are not obtained in the foregoing
same bit-pieces forms as are the styrene-polymers and lower
polyolefins, but rather in continuous foamed blocks as a result of
the reaction that provides the polyurethane. Accordingly, the
foamed polyurethane blocks first are shredded into bit-pieces (for
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 in
my copending United States of America patent application Ser. No.
833,643 filed Sept. 15, 1977 .Iadd.now U.S. Pat. No.
4,200,679.Iaddend.) as comprising broken and interconnected strand
portions from adjacent cells of the flexible foam, which strand
portions show substantially total absence of intact cells and cell
windows and are tripodal particles with generally uneven length
legs, the strand portions having hook-like projections,
indentations and flutes resulting from destruction of the cells and
cell windows of the starting flexible foam.
The micro-bits of any expanded thermoplastic, non-brittle in
expanded form styrene-polymer or expanded lower polyolefin or
flexible foamed polyurethane are prepared by disintegrating the
respective starting expanded polymer bit-pieces in a comminuting
machine such as that produced by Fitzpatrick Company (of 832
Industrial Drive, Elmhurst, Illinois 60120, U.S.A.) according to
their Bulletin No. 152 copyright 1968 using the broached fixed
blades (identified therein by "Code DS225") to replace the blades
or other comminuting elements, mounted for rotation in the
comminuting chamber model DAS06, both shown on that bulletin's page
5. That chamber is liquid-tightly capped, for example, by a cover
such as shown in their Code M44D6 or Code MA44D6 (upper half of
page 3 of their Bulletin 152).
That model DAS06 comminuting chamber is rectangular in horizontal
cross-section and has a pair of opposed parallel entirely vertical
walls integrally joined at each of their opposite ends by a
separate one of a pair of opposed vertically arcuate walls each
with its convex face exposed to the exterior.
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 shaft
and intermediate its free outer mounting ends. These arms extend
radially out from the shaft (e.g. 127 mm. from its axis to the
outer end of each arm) with the first of each consecutive four of
them extending horizontally toward one arcuate wall, the second of
each four extending vertically, the third four of them extending
toward the other arcuate wall, and the fourth four of them
extending vertically downward.
Each arm is rectangular in cross-section in a plane running through
the entire length of the shaft's axis and of that arm, and of each
arm 180.degree. removed from it. The outer end of each arm meets at
right angles with its two wider sides (5.4 mm. width) and its
narrow or impact side (9.525 mm. wide) facing the direction of
rotation. That narrow side also meets at right angles with the two
wider sides which are parallel to one another for most of their
width and with the trailing third of their surfaces tapering to one
another and terminating in the knife edge of their trailing
end.
Each free exposed end of the shaft extends through its respective
stuffing box in its neighboring one of the two parallel vertical
walls on through a bearing carried on a respective trunnion affixed
to the machine's foundation and spaced outwardly away from the
respective wall. A driving pulley is mounted on each end of the
shaft extending outwardly from its respective mounting
trunnion.
The bottom of the comminuting chamber is an exchangeable
dish-shaped, arcuate screen curved convexly downward with an inside
radius (from the axis of the operating shaft) equal to the length
of a comminuting arm plus 0.762 mm. clearance. The screen's overall
rectangular peripheral opening has such dimensions and shape as to
enable it to be removably fitted in a liquid-tight engagement with
the bottom of the four walls of the comminuting chamber.
The screen has staggered rows of, for example, circular holes
varying in diameter as from 0.102 to about 3.175 mm. and closely
spaced to one another with sufficient space between them for the
screen to hold up under working conditions.
Except for its starting material feed hopper inlet at one side of
it, the rest of the chamber's cover is arcuate and convex upwardly
with a radius (from the axis of the operating shaft) sufficient for
the rotating arms to have a 0.762 mm. clearance from the inwardly
facing surfaces of a plurality (e.g. three) pre-breaker bars (about
20.32 cm. long and 6.35 mm. wide) protruding for 3.175 mm. along
their entire length of the interior of the comminuting chamber, and
extending spaced apart from one another and parallel to the axis of
the operating shaft.
The 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 from about 5000 to about 7500
r.p.m.
The invention includes also a form of these mats, which can be
called the gas-vapor adsorption filtering or treating mats. These
include the basic or primary constituents (a) the glass fibers, (b)
the micro-bits, and (c) the organic binding agent, each being
within its earlier above recited respective range relative to the
others of them, and together with an amount of any of (i) finely
divided activated carbon (as primary gas-adsorbing agent) and (ii)
finely divided molecular sieve particles (such as described further
below) and under that at which undesirable dusting off of carbon or
molecular sieve particles can occur, also a sufficient amount of
the cobeat to serve to restrain the carbon or molecular sieve
particles against dusting off, and an amount of a fiber-forming
terephthalate polyester sufficient to hold the mat's tensile
strength within its earlier above recited range without undesirable
lowering of the mat's porosity.
Thus, for example, in addition to its three primary constituents
(a), (b) and (c), these adsorption filtering and treating mats can
contain, of their overall content, the activated carbon to a
maximum of about 50%, the molecular sieve particles to the extent
of about 75%, the polyester fibers in the range from about 2% to
about .[.7.5.]. .Iadd.12.2.Iaddend.%, and from about 2% to about
30% of cobeat.
Any of the gas-adsorbing activated carbons from their various
sources, for example, charcoal, coal, petroleum distillation
residue or pecan nut shells, can be used.
The herein applicable molecular sieve particles are referred to as
the gas-vapor adsorbent zeolite molecular sieve particles. They are
any of the crystalline, natural or synthetic zeolites of the type
more specifically described further below.
The invention also involves the method of preparing these mats of
this invention. Broadly the preparation of the gas-vapor treating
mats comprises dispersing in water in a pulper (as used in paper
making) an amount of (a) micro-bits of any of an expanded,
thermoplastic styrene-polymer, and expanded lower polyolefin from
polyethylene to poly-methylpentene and a flexible polyurethane,
each said polymer being non-brittle in its expanded form, and (b)
glass fibers composed of the glass filaments, as described above,
and agitating the mixture of (a) and (b) for the brief time at
least sufficient for each of them to be substantially free of
clumps and clusters and substantially uniformly intermixed, .[.and
in the proportion of from about 5 to about 50 parts of the
micro-bits to from about 4 to 45 parts of glass fibers,.]. admixing
an organic binding agent (as described earlier above) or a cobeat
(as described further below) in an amount sufficient for the
finished mat to have surface tension and porosity with each of them
being within its respective earlier above recited range; then
transferring the resulting mixture in a concentration of from about
0.1% to 0.5% of the admixed micro-bits and glass fibers to a supply
chest and therein agitating their mixture merely sufficiently to
maintain a uniform dispersion.
The dispersion then is fed from the supply chest to the furnish box
(of the Fourdrenier machine) at the rate, for example, from about
3.3 to 5.5 kg. (i.e. kilogram) per minute and at the same time is
diluted uniformly with water fed into the furnish box at the rate
of from 3,800 to about 9,000 liters per minute.
The resulting diluted furnish slurry then is fed onto the
Fourdrenier screen moving at a rate to provide a wet mat which
after drying has a basis weight of from about 2.25 to about 22.5
kg; and continuously removing the web mat from the screen and
running it through a suitable drying operation.
The gas-vapor treating mat can be prepared by including adding to
the mixture in the pulper, beneficially before admixing any binding
agent a separate amount of each of sodium hexametaphosphate and
concentrated sulfuric acid and in such proportion to one another
sufficient to lower the pH of the mixture to 2.5.
The gas-vapor adsorption treating mats are prepared by a
combination of steps comprising preparing a cobeat suspension of
wet lap cotton fibers and micro-bits in water (as described further
below) and separately producing a suspension of micro-bits in water
in the proportion recited further below.
Then a furnish supply suspension is prepared by admixing in water
an amount of the cobeat suspension within a given range and adding
a quantity of a fiber-forming polyethylene terephthalate polyester
in a quantity to partake in providing the finished mat with tensile
strength within an effective range without adversely affecting its
porosity. Then any of the finely divided activated carbon and/or
molecular sieve particles are admixed within the range up to a
maximum of about 50% (for the carbon alone), and 75% (for the
molecular sieve particles alone) of the planned total solids of the
finished mat, and an aqueous suspension of the microbits is added
in an amount to provide in the finished mat from about 5% to about
30% of micro-bits.
The .[.remaining addition admixed.]. .Iadd.resulting admixture
.Iaddend.is a suspension of glass fibers, micro-bits and binding
agent, each within its respective range as earlier recited for the
gas-vapor treating mat and so proportioned to the other solids for
the finished mat to have the planned tensile strength and porosity.
The finally resulting suspension from all of these included
constituents is fed 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 Fourdrenier
screen and dried as with the other mats.
In each of the procedures preparing a mat wherein an organic
binding agent is used, it is beneficial to add that agent to the
suspension (being prepared) within the last minute or so of the
agitation before the suspension is to be fed to the (machine)
supply chest and also that the web leaving the Fourdrenier screen
initially is subjected to radiant heat from a relatively close
source at a temperature in the range of from about 600.degree. C.
to about 700.degree. C. That rapidly causes the solution of the
.[.polyester.]. .Iadd.binding agent .Iaddend.in the water carried
by the mat and enhances the drying of the .[.polyester.].
.Iadd.binding agent .Iaddend.at the intersections of the
water-insoluble constituents.
The preparation of 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 following preparation of polystyrene micro-bits:
EXAMPLE A--Micro-Bits From Expanded Extruded Polystyrene
Pellets
425 liters of expanding-agent-impregnated, extruded polystryene
pellets (crystal) expanded to from about 6.35 to about 12.7 mm.
substantially round pellets having a bulk density of 12 grams per
liter were comminuted in a comminuting machine (as described
earlier above) equipped with an input feeder 10.16 cm. in diameter
by 7.62 cm. long and a bottom arcuate screen with holes of 0.1016
mm. diameter.
The rotor was set to run at 6,000 r.p.m. and the feeder set to
charge the expanded polystyrene bit-pieces at the rate of 35.4
liters every 5 minutes (i.e. 425 liters per hour). The starting
expanded polystyrene bit-pieces to be introduced into the feeder
were wetted with sufficient water substantially completely to cover
their outer surfaces. The thus wetted expanded polystyrene
bit-pieces were charged into the feeder continuously at a rate of
35.4 liters every 5 minutes, while at the same time water was
injected into the comminuting chamber through the two 1.6 mm.
diameter jet orifices at a rate of 7.57 liters per minutes.
The mixture of the expanded polystyrene micro-bits in water leaving
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 polystyrene micro-bits in the water
physically bound to them. The 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 22.71 liters of
water were expressed. The remaining 4.08 kilos containing 544 grams
of expanded polystyrene micro-bits then were dried in an open dish
in an oven maintained at 43.33.degree. C.
Micro-bits of any other thermoplastic expanded styrene-polymer of
lower polyolefin, each non-brittle in expanded form, or of any
flexible foamed (i.e. expanded) polyurethane non-brittle in its
foam or expanded form 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 Example A starting with the micro-bits of each such other
applicable expanded polymer is to be considered as if incorporated
herein in full as a separate example, thereby avoiding
unnecessarily extending this specification.
The preparation of the gas-vapor treating mats of the invention is
illustrated by, but not limited to, the following examples:
EXAMPLE 1
Basic Gas-vapor Treatment Mat
Into 15,139 liters of water charged into a (paper making) pulper
(of very little greater capacity), there was fed by an endless belt
conveyor 23.27 kilos (dry basis) of polystyrene micro-bits (in the
form of water-bound product containing 8% micro-bits solids). The
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.
While agitating the mixture, 22.73 kilos of sodium hexametaphosphat
were admixed and followed by admixing 3.785 liters of concentrated
sulfuric acid (98.6% H.sub.2 SO.sub.4). That brought the pH of the
batch to 2.5.
The agitation was stopped while there was added (from a number of
cartons) a total of 113.64 kilos of 6.35 millimeters (length) glass
fibers (diameter 6.3 microns) Owens-Corning electrical grade DE 636
as the number of filaments per bundle (and bound by a starch, oil
and cationic surfactant binder).
The rotor agitation was resumed and continued for 10 minutes,
during the last 30 seconds of which 10.25 kilos of (cold)
water-swellable polyvinyl alcohol (98% hydrolyzed) (herinafter
called PVA) fibers were added as binding agent. The thus completed
initial pulper mix was pumped to the beater chest (serving only as
holding facility to receive amounts of pulper mix) and agitated
there merely sufficiently to maintain the insolubles in
suspension.
7570 liters of (rinse) water then were added to the pulper and
agitated to suspend any glass fibers and/or micro-bits which
settled out and remained behind while the initial pulper mix was
being pumped to the beater chest. The resulting so-called pulper
rinse mix then was pumped to the beater chest and there admixed
into the initial pulper mix to provide the starting mat-making mix
containing 0.64% solids.
This starting mat-making mix then was pumped to the machine chest
(also a supply holding chest) with its contents maintained under
agitation also as in the beater chest. From this supply chest the
mat-making mix was fed to the furnish box for the Fourdrenier at a
rate of 4.32 kg. solids per minute and there combined with clear
dilution water at a rate of 6056 LPM.
The resulting uniform web-furnish slurry (as diluted in the furnish
box) was fed onto the traveling Fourdrenier screen (86 strands in
the machine direction and 60 strands across) moving at a rate of
15.24 meters per minute (i.e. MPM) to enable providing an initial
web mat which after later finished drying showed a basis weight of
19.1 kg.
The 9.525 mm. thick wet mat (on the Fourdrenier) after passing the
suction boxes under the leaving end of the Fourdrenier screen
continued onto an endless belt conveyor (a 112 by 84 mesh screen)
also at 15.24 MPM. Then after about 1.5 meters beyond that end of
the Fourdrenier, the wet mat (on that conveyor) passed about 10 cm.
below a battery (about 60.5 cm. long) of infrared lamps (52.4
kilowatts, at 3.8 amperes, 480 volts, single phase 60 cycle)
providing at the mat surface a rheostat set temperature of possibly
649.degree. C. The exposure of the wet mat to that temperature thus
for about 2.4 seconds quickly caused solution of the PVA.
The partially dry web continued through a tunnel dryer (about 3.67
meters long by 1.83 meters wide) providing a temperature of about
121.degree. C. and then alternated in sequence over one and then
under the next of each of a series of six dryer drums (the first
drum providing a temperature of 113.degree. C. with the temperature
increased at each of them that followed with the last drum
maintained at 127.degree. C. The finally dry mat then passed
through a pair of tension rollers and onto a wind up drum. That dry
mat web with a smooth surface on each side wound up easily around
that drum without any tears or wrinkles.
At its basis of 19.1 kilos, the finished gas-vapor treating web
showed a porosity value (by Gurley porosity meter) of about 602.8
liters per minute (i.e. LMP) per square decimeter (i.e. sq. dcm.)
of surface at a test differential air pressure of 2.54 centimeters
of water (gage).
Based on the starting amounts of the essential materials, the
finished dry gas-vapor treating mat contains about 15.8% of the
expanded polystyrene micro-bits, about 77.2% of glass fibers and
about 6.97% of polyvinyl alcohol binder. The content of these
essential constituents may be varied in accordance with desired
variations in porosity, gas or vapor fluid flow rate and density by
suitable variations in the constituents content. For example, the
porosity can be decreased by lowering the micro-bits content to any
level down to a minimum of about 2% without corresponding decrease
in tensile strength.
Alternatively, the porosity and flow rate can be increased by
increasing the micro-bits content, as in some formulations, to any
level even up to 50%, of the total solids.
Example 1 can be repeated by reducing the quantity of sulfuric acid
in part or as a whole and also by reducing the amount of sodium
hexametaphosphate (ordinarily used to enhance glass fibers
dispersion) in whole or in part in preparing the initial pulper
suspension, in view of the indication that the micro-bits appear to
enhance dispersion of the solid constituents during agitation in
the water.
Depending on the anticipated ultimate use of the gas-vapor treating
mat its basis weight can be reduced or enlarged by either
decreasing or increasing the solids content in the aqueous furnish
in the furnish box or increasing or reducing the speed of the
Fourdrenier screen.
EXAMPLE 2
Basic Gas-vapor Treating Mat With Polyurethane Micro-Bits
Into a 3.5 liter stainless steel beaker containing 3 liters of
water, there was dispersed 21.5 grams of (furniture grade) flexible
polyurethane micro-bits containing 20% solids (thus 4.3 grams of
micro-bits dry basis and 17.5 cc. of water) by an air driven
stirrer. Then 15 grams of the same 0.635 cm. length DE 636 glass
fiber (as of Example 1) were added and agitation continued. In the
last 10 minutes of an hour of stirring there were admixed 1.375
grams of the PVA (same as in Example 1).
Six-tenths of the resulting 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 of the slurry developing in sheet form on the
screen and the water dripping through the screen by gravity from
the increasing density slurry. After no further water drained off
by gravity, the wet sheet was dried in a drying oven by a hot air
stream of 121.degree. C. flowing 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 minute per
square decimeter at a pressure differential of 2.54 cm. (H.sub.2
O).
Example 2 includes no sodium hexametalphosphate 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 of the other effective polymers.
EXAMPLE 3
Example 2 Mat With Cobeat Binder Instead Of PVA
Example 2 was repeated except that during the agitation after
admixing the glass fibers, instead of PVA there was admixed 60
grams of the cobeat suspension of Example 5 amounting to 1.2 grams
of the cobeat solids (composed of beater beaten, interlocked wet
lap cotton fibers and polystyrene micro-bits). The preparation of
the mat then was completed as in Example 2. The resulting dry mat
showed porosity of 335 liters per minute per sq. dcm., at 2.54 cm.
(H.sub.2 O) differential pressure (gage), and tensile strength of
0.61 kg. per cm.
EXAMPLE 4
Example 3 With Polystyrene Replacing Polyurethane
Example 3 was repeated by using polystyrene micro-bits instead of
the polyurethane micro-bits, and also cobeat as the binder instead
of PVA. The resulting dry web showed tensile strength of 0.22 kg.
per cm. and porosity of 305 LPM per square decimeter at
differential pressure of 2.54 cm. (H.sub.2 O).
The adsorbent (constituent) containing gas-vapor filtering or
treating mats of this invention are illustrated by, but not
restricted to, the following:
EXAMPLE 5
Activated Carbon-containing Adsorption Mat
(a) Cobeat Suspension Preparation
A cobeat suspension (so-called because wet lap cotton fibers 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, containing 1454.4 liters of water in the fibers)
and 181.8 kilos (dry basis) of polystyrene micro-bits (6% solids
with 2848.5 liters of bound water) into 13,354 liters of water in a
pulper and agitated for 3 minutes (as in Example 1) thereby
dispersing 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% of maximum and
run at 110 r.p.m. for 6 hours (when the freeness starting at 760
was found 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. The desired end occurred in two hours when the freeness
was found reduced to 450. The beater content (now the cobeat
suspension) was retained in the beater under merely sufficient
agitation for the dispersion to remain in suspension for later
use.
The wet lap 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 4.23 mm. to about 1.27 cm. in length, fed
to a wet lap machine and from it as a web between pressure rolls
and leaving as a web about 2.1 mm. thick (containing about 80%
moisture) and then lapped up and back over and over on a pallet
usually to a pile of about 363.8 kilos gross weight.
(b) Micro-bits Suspension
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 containing 16% micro-bits solids and 715.9 liters of water)
and agitated to a uniform dispersion and maintained under merely
sufficient agitation for that until shortly needed.
(c) Furnish Supply Suspension
A furnish 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
suspension, thus providing a diluted cobeat suspension.
(iii) followed by admixing 91 kilos of readily water dispersible,
semi-dull, optically whitened polyethylene terephthalate polyester
(beneficially in 1.27 cm. long fibers of 1.5 denier spun by
conventional melt .[.process,.]. .Iadd.process) having a special
finish compatible with most anionic, cationic or nonionic binders
(and providing rapid and excellent dispersion with a wide variety
of furnish systems and additives), and solution viscosity of
770.+-.20 of 1/2 gram dissolved in 50 ml. of solvent (by weight, 40
parts .[.and.]. tetrachloroethane and 60 parts phenol) at
25.degree. C. (solution viscosity is the viscosity of the polymer
solution divided by the viscosity of the solvent, with the result
minus one multiplied by 1000); melting point 48.67.degree. C.,
non-shrinkable in boiling water, and elongation at break 45%
(available as TREVIRA 101, product of American Hoechst Corporation,
Fibers Division, Spartenburg, South Carolina 29301),
(iv) admixing 172.7 kilos of finely divided activated carbon
(Nuchar S-N, product of Westvaco Corporation, Covington, Va.
24426); and also
(v) admixing the foregoing micro-bits suspension containing the
136.4 kilos (dry basis) of polystyrene micro-bits as the
water-bound product (having about 16% micro-bits solids) thereby
adding 716 liters of water to the 7570 liters initially included;
and finally
(vi) adding 4163.5 liters of 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 of suspended solids.
(d) Glass Fibers, Micro-Bits And Binder Suspension
This suspension was prepared by the procedure used in (the first 4
paragraphs of) Example 1 by charging into a pulper 11,354 liters of
water, admixing 22.73 kilos (dry basis) of polystyrene micro-bits
as the water-bound product (containing 6% solids and 356 liters of
water), dissolving 22.73 kilos of sodium hexametaphosphate and 3.8
liters of sulfuric acid (98.6%), and admixing 113.64 kilos of the
same 6.35 mm. length glass fibers and 10.23 kilos of the same PVA
fibers. This suspension then was pumped to a beater chest.
The pulper then was rinsed by adding 3785 liters of water and
agitating the content as in Example 1. The resulting rinse
suspension then was admixed with the pulper suspension in the
beater chest, thus providing the glass fibers, micro-bits and
binder suspension, as the second member of the constituent (vi) of
the furnish supply suspension.
While maintained under agitation in the beater supply chest, this
uniformly admixed furnish supply suspension was fed to the
Fourdrenier machine head box at the same rate and admixture with
dilution water as in Example 1, and onto the moving Fourdrenier
screen. After 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 over the series of six dryer drums.
The final activated carbon-containing adsorbing mat was uniform in
appearance with a basis weight of 15 to 15.45 kg., porosity of
353.7 liters per minute per square decimeter at a pressure
differential of 2.54 cm. (H.sub.2 O), and tensile strength of 1.074
kilos per cm. in the machine direction and 0.895 kilos per cm. in
the cross direction.
EXAMPLE 6
Molecular Sieve-Containing Adsorption Mat
Example 5 was repeated but with its 172.7 kilos of activated carbon
replaced by the same amount of the gas-vapor adsorbent, zeolite
molecular sieve powder particles having nominal pore diameter of 5
Angstroms and the chemical formula Ca.sub.4.5 Na.sub.3
[(AlO.sub.2).sub.12 (SiO.sub.2).sub.12 ]. The resulting mat showed
tensile strength much like that of the mat of Example 5 and
porosity of about 410 liters per minute per square decimeter at
2.54 cm. (H.sub.2 O).
The polystyrene micro-bits of Examples 1, 4, 5 and 6 can be
replaced in part or as a whole by micro-bits of any other of the
applicable expanded thermoplastic styrene-polymers or of expanded
lower polyolefins or of flexible polyurethanes, each of them
non-brittle in expanded form. Thus, each such repeat of Examples 1,
4, 5 and 6 by the just indicated replacement of expanded
polystyrene micro-bits is to be considered as if occurring herein
in full as a complete example, thereby avoiding making this
specification prolix. The lower polyolefins from polyethylene to
poly-methylpentene include also polypropylene and polybutene.
In any of Examples 1 to 5, and any of the just above indicated
modifications of any of them, the micro-bits can be provided with
any amount of water held by them as well as in the dry state. The
micro-bits were provided in these examples as used along with
different amounts of water held by them, because of their ready
availability in that form and their thus lower cost.
Similarly, the cotton fibers used in preparing the cobeat were
provided in their form as wet lap cotton fibers, ordinarily
containing about 80% of water, because of the economy in doing so.
However, that does not preclude using these cotton fibers in the
dry state when thus available or desired for any particular
reason.
The Westvaco's NUCHAR S-N activated carbon in Example 5 can be
replaced by any other Westvaco activated carbon. For example, if
the mat is to be used for adsorbing phenol, Westvaco's NUCHAR N-A
(yielding an acid wash water when washed in water) would be
beneficial because that acid grade manifests higher adsorption of
phenol.
Either of these two grades of activated carbon can be replaced by
any of the others available, for example, DARCO now available from
I.C.I. (U.S.A.) Ltd., and the NORIT product of American Norit Co.
The Barneby-Cheney activated carbon from pecan nut shells is highly
effective, for example, in the adsorption of sulfur dioxide from a
gas stream, for which it showed a very much greater adsorption
capacity than an activated carbon from another source. Thus,
Example 5 is to be considered as if presented written out in full
with its activated carbon replaced by the Barneby-Cheney product,
or any other available suitable finely divided activated
carbon.
The polyester of Examples 5 and 6 can be replaced by any other
fiber-forming terephthalate polyester, for example, the FORTREL
polyethylene terephthalate or by the KODEL dimethyl 1,4-cyclohexane
dimethanol terephthalate. The molecular sieve particles of Example
6 (The Linde 5A product Union Carbide Corporation of 270 Park
Avenue, New York, N.Y.) may be replaced as a whole, or in part, by
any other such molecular sieve particles, e.g. having nominal pore
diameter of from 4 to about 10 Angstroms. Examples 5 and 6 and the
thus resulting examples derived from them are to be considered as
if presented as written out in full with the polyester or molecular
sieve particles separately respectively replaced by each one of
these other polyesters or molecular sieve particles. Any of the
polyesters can be used in any of the available 1.5 and 3 denier
diameters.
The mats of this invention are effective for removal and/or
recovery of various gases or vapors, either inorganic or organic,
for example, sulfur dioxide, chlorinated alkanes sucgh as carbon
tetrachloride and other chlorinated alkanes, and benzene and
phenol.
While the invention has been explained by detailed description of
certain specific embodiments of it, it is understood that various
substitutions or modifications can be made in any of them within
the scope of the appended claims which are intended to cover also
equivalents of these embodiments.
* * * * *