U.S. patent number 3,895,143 [Application Number 05/342,159] was granted by the patent office on 1975-07-15 for metal-fiber-latex-containing sheet materials.
This patent grant is currently assigned to Nicolet Industries, Inc.. Invention is credited to Hilton J. Tarlow.
United States Patent |
3,895,143 |
Tarlow |
July 15, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Metal-fiber-latex-containing sheet materials
Abstract
Sheet material consisting essentially of inorganic fibers, such
as asbestos fibers, elastomer latex, such as neoprene latex, and
finely divided metallic material, such as lead, the inorganic
fibers being felted together and coated and adhered together by the
elastomer latex and formed into a sheet, with the finely divided
metallic material being maintained in the resulting formed sheet
and affixed to the inorganic fibers by the elastomer latex, the
sheet material preferably being coated on one surface with a
water-impermeable material, such as bitumen or tar, or a
water-resistant material, is useful as a pipe wrapping, such as
pipe wrapping for gas transmission lines, as vibration dampening
material or sound deadening material when affixed to a surface or
as a radiation shielding material. The above-described sheet
material is formed by preparing a watery admixture or furnish
containing the inorganic fibers, latex and lead dispersed therein,
effecting precipitation of the latex material onto the dispersed
inorganic fibers and/or metallic material, followed by subjecting
the resulting watery admixture to agitation and then forming a
sheet therefrom by discharging or flowing the aqueous admixture
onto a paper-making screen or sheet-forming roll or surface.
Inventors: |
Tarlow; Hilton J.
(Philadelphia, PA) |
Assignee: |
Nicolet Industries, Inc.
(Ambler, PA)
|
Family
ID: |
23340617 |
Appl.
No.: |
05/342,159 |
Filed: |
March 16, 1973 |
Current U.S.
Class: |
428/40.9;
162/153; 162/155; 181/294; 250/515.1; 376/286; 376/288; 428/220;
428/328; 428/354; 524/439; 976/DIG.334 |
Current CPC
Class: |
E04B
1/8409 (20130101); F16L 59/028 (20130101); G10K
11/165 (20130101); G21F 1/125 (20130101); C09J
7/22 (20180101); C09J 2421/006 (20130101); Y10T
428/256 (20150115); Y10T 428/2848 (20150115); E04B
2001/8461 (20130101); C09J 2400/163 (20130101); C09J
2400/263 (20130101); Y10T 428/1438 (20150115); C09J
2411/006 (20130101) |
Current International
Class: |
G21F
1/12 (20060101); G21F 1/00 (20060101); E04B
1/82 (20060101); E04B 1/84 (20060101); C09J
7/02 (20060101); F16L 59/02 (20060101); G10K
11/16 (20060101); G10K 11/00 (20060101); B32b
019/02 () |
Field of
Search: |
;161/167,406,158,165,205,217,218,182,DIG.4,204,159,160
;162/152,153,155 ;250/515,517 ;181/33G ;260/42.22,42.55 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lesmes; George F.
Assistant Examiner: McDonald; Alan T.
Attorney, Agent or Firm: Cooper, Dunham, Clark, Griffin
& Moran
Claims
I claim:
1. Sheet material consisting essentially of asbestos fibers, a
polymer latex selected from the group consisting of neoprene latex
and acrylonitrile-butadiene latex and finely divided lead, said
asbestos fibers being present in said sheet material in an amount
in the range about 5-30% by weight and being felted together and
coated and adhered together by said polymer latex and formed into a
sheet, said polymer latex being present in said sheet material in
an amount in the range abour 2-20% by weight and said finely
divided lead being maintained in the resulting formed sheet
material and affixed to said asbestos fibers by said polymer latex,
said finely divided lead comprising at least about 50% by weight of
said sheet material.
2. Sheet material in accordance with claim 1 wherein said finely
divided lead has a particle size smaller than 200 mesh.
3. Sheet material in accordance with claim 1 wherein said polymer
latex is neoprene latex.
4. Sheet material in accordance with claim 1 wherein said polymer
latex is a acrylonitrile-butadiene latex.
5. Sheet material in accordance with claim 1 wherein a coating of a
pressure-sensitive adhesive is applied to at least one surface or
side of said sheet material.
6. Sheet material in accordance with claim 1 wierein a coating of
pressure sensitive adhesive material is applied to both sides or
surfaces of said sheet material.
7. Sheet material in accordance with claim 1 wherein a coating of
pressure-sensitive adhesive material is applied to at least one
side or surface of said sheet material and a film or layer of
protective, strippable or peelable material is applied on top of
said coating of pressure-sensitive adhesive material.
8. Sheet material in accordance with claim 1 wherein said sheet
material has a thickness of about 0.01 to about 0.25 inch.
Description
This invention relates to sheet materials useful as vibration
dampening agents, sound deadening agents, gasketing material,
special wrapping material, such as pipe wrapping material, and
radiation shielding material. In one particular embodiment this
invention relates to flexible sheet material made up of high
density metallic material, such as lead, admixed with inorganic
fibers. In another embodiment this invention relates to stiff of
rigid sheet material made up of inorganic fibers, such as asbestos
fibers, metallic material, such as finely divided or powdered
metal, and a thermoset resin which serves to impart strength and
rigidity or stiffness to the sheet material. In another embodiment
this invention is directed to a method for the manufacture of high
density, inorganic fiber-containing sheet material. In still
another embodiment this invention is directed to a method for the
manufacature of limp and/or flexible sheet material characterized
by high density and useful as radiation shielding or vibration
dampening or sound deadending material.
Sheet materials useful as sound deadening or vibration dampening
materials have been prepared by incorporating or otherwise affixing
finely divided or powdered lead to a heavy cloth, such as canvas.
Such materials, howver, have not been completely satisfactory,
particularly when exposed for a long period of time to the weather
or when employed in a demanding environment, such as when employed
as a pipe coating, in underground gas transmission lines.
It has also been suggested to disperse or otherwise incorporate
finely divided metal, such as powdered lead, in a plastisol, such
as a polyvinyl chloride plastisol. The resulting materials while
satisfactory for many purposes are expensive and are not durable.
Also, with respect to lead-loaded canvas sheets or polyvinyl
plstisol lead-loaded sheets, it has been difficult and costly to
manufacture such materials since specialized equipment is
necessary.
Accordingly, it is an object of this invention to provide an
improved sheet material useful as a vibration dampening or sound
deadening material.
It is another object of this invention to provide a method, such as
a method employing paper-forming techniques and/or equipment or
machinery, for the manufacture of sheet material useful as a sound
deadening or vibration dampening or radiation shielding
material.
How these and other objects of this invention are achieved will
become apparent in the light of the foregoing disclosure and with
reference to the accompanying drawing which schematically
illustrates in an enlarged cross-section one embodiment of sheet
material prepared in accordance with the practices of this
invention.
It has been discovered that sheet material consisting essentially
of inorganic fibers, such as asbestos fibers, and a latex, e.g. an
elastomer latex, such as neoprene latex, and finely divided,
preferably high density material, such as metallic material, e.g.
powdered lead, the inorganic fibers being substantially felted
together and coated and adhered together by the elastomer latex and
formed into a sheet with the finely divided metallic material,
preferably high density inorganic or metallic material, being
maintained in the resulting formed sheet and affixed to the organic
fibers by the precipitated elastomer latex, is useful as a pipe
wrapping or vibration dampening or sound deadening material.
Preferably, the sheet material is coated on one surface with a
water-impermeable or water-resistant material, such as bitumen or
tar. If desired, one side of the resulting formed sheet material
may be coated with a pressure sensitive adhesive so that the
resulting coated sheet material can be readily affixed or attached
to a surface. If desired, there may also be incorporated in the
resulting formed sheet material a thermosetting agent which, upon
curing, converts the sheet material to a substantially rigid or
stiff sheet. It is preferred, however, that the sheet material be
flexible or limp and made up of high density material, succh as
finely divided or powdered lead, so that the resulting formed sheet
material is especially useful as vibration dampening or sound
deadening material, particularly with respect to low frequency
vibrations.
In the make-up of the sheet material in accordance with this
invention it is also preferred that the fiber content of the sheet
material be comprised of substantially 100% inorganic fibers, such
as at least about 60% by weight inorganic fibers. Particularly
useful as asbestos fibers. If desired, however, there may be
employed in place of or together with the asbestos fibers other
inorganic fibers, such as carbon fibers, boron fibers, rock wool
fibrous material, glass fibers, ceramic fibers, such as alumina
fibers, and the like.
Further, as indicated hereinabove, or major or minor portion of the
total fiber content of the sheet material may be comprised of
organic fibrous material, such as paper pulp, paper, cloth and
organic fibers, such as nylon, rayon, dacron, cotton, acetate, wool
and the like. It is preferred, as already mentioned, that when
organic fibers are present in the sheet material the organic fibers
comprise less than 50% by weight fiber content based on the weight
of the total fibers making up the sheet material, and desirably
less than about 25-30% by weight of the total weight of the
resulting formed sheet material.
In the sheet material in accordance with this invention there is
also incorporated therein a finely divided or powdered inorganic,
preferably metallic material. Particularly useful as the finely
divided or powdered metallic material useful in the preparaton of
the sheet material is finely divided or powdered metal.
Substantially may powdered metal is usefully incorporated in and
employed in the manufacture of sheet material in accordance with
this invention. Suitably finely divided or powdered metals include,
iron, brass, stainless steel, zinc, bronze, copper, beryllium,
aluminum, silver, chromium, titanium, cobalt, nickel, tantalum,
molybdenum and alloys or mixtures of one or more of the above.
Also useful as finely divided or powdered inorganic or metallic
material useful in the sheet materials in accordance with this
invention are such diverse materials as molybdenum disulfide,
graphite, barytes or barium sulfate, zinc oxide, zinc sulfide,
tungsten carbide, lead sulfide, lead oxide and the like. Desirably,
and preferably, when the sheet material is to be used as a
vibration dampening or sound deadening material the finely divided
or powdered inorganic material is a high density material, such as
a metal or inorganic material having a specific gravity greater
than 5, preferably greater than 8. Particularly useful as a high
density finely material making up the sheet material is finely
divided or powdered lead or similar high density metals and
compounds, i.e. specific gravity greater than about 10-12.
The elastomer latex employed as the binder for the associated
fibrous material and inorganic or metallic material making up the
sheet material of this invention may be substantially any
commercially available elastomer latex. Suitable elastomer latices
would be a butadiene-acrylonitrile latex, such as Buna-N, neoprene
latex, a styrene-butadiene latex, and
acrylonitrile-butadiene-styrene latex, a polybutadiene latex, a
polyisoprene latex, natural rubber latex, polyvinylchloride latex
and the like.
It is preferred in the practice of this invention to employ a
latex, such as acrylonitrile-butadiene latex or neoprene latex of
polyvinylchloride latex, which is weather and/or oil resistant and
which imparts suitable properties of flexibility and/or limpness
and toughness and stability to the sheet material as well as
non-flammability.
The amount of latex making up the sheet material is a minor amount,
such as less than 20% by weight of the sheet material, usually in
the range 2-10% by weight of the sheet material, as opposed to the
fiber content which would be in the range not more elastomer about
50-60% by weight of the sheet material, usually in the range 5-30%.
The finely divided or curing inorganic or powdered material making
up the sheet material of this invention usually comprises a
substantial amount of the 53 material, such as at least about
10-20% by weight. Desirably, and preferably, in accordance with
this invention, the finely divided powdered inorganic or metal
material makes up at least 50% by weight and most desirably at
least about 65-70% by weight on up to about 85-90% by weight of the
sheet material, especially when the sheet material is to be
employed as a vibration dampening or sound deadening or radiation
shielding material.
There may also be incorporated in the sheet material other
materials, such as an antioxidant or heat and light stabilizers for
the latex component thereof, to improve its weathering properties
and resistance to oxidation, filling agents or color agents, such
as inorganic materials, e.g. calcium carbonate, or dyes to impart a
desirable color to the sheet material. Also, as indicated,
particularly when a stiff or rigid sheet material is desired, there
may also be incorporated in the sheet material during its
manufacture a cross-linking agent effective upon curing to react or
cross-link with the elastomer component. If desired, there may also
be incorporated in the sheet material during manufacture a minor
amount of a thermosetting resin effective upon curing or
thermosetting to impart stiffness and/or rigidity to the resulting
formed sheet material.
Further, as indicated hereinabove, the sheet material may be coated
on one or both sides or surfaces with a pressure-sensitive adhesive
or other suitable adhesive material so that the thus
adhesive-coated sheet material may be readily and easily attached
to a surface, such as a supporting surface, by merely applying the
adhesive coated surface of the sheet material thereto. When the
sheet material is adhesive-coated on both sides and after
application or affixing one side of the sheet material to a
supporting surface there may be applied to the other or remaining
exposed adhesive-coated surface of the sheet material another
material or structure so that the adhesive-coated sheet material is
incorporated or installed between two structures or surfaces.
For handling purposes the pressure-sensitive or adhesive-coated
surface of the sheet material has attached thereto a peelable or
readily removable coating or layer of material, such as a plastic
film or waxed paper, which would be stripped from the
adhesive-coated surface just before the adhesive-coated surface of
the sheet material is applied to the structure or surface to which
the sheet material is to be attached or installed.
It has been mentioned hereinabove that the sheet material in
accordance with this invention in at least one embodiment is
capable of being manufactured on conventional web or paper forming
equipment. The fact that the sheet material of this invention which
includes a substantial amount of finely divided or powdered
inorganic material, such as finely divided lead, can be
satisfactorily manufactured on paper or other sheet-forming
equipment is surprising since it would appear that one would expect
that there would be a substantial loss or drainage away of the
finely divided powdered metal with the water flowing or draining
through the paper or sheet-forming screen.
In the accompanying drawing there is illustrated in enlarged
partial cross-section an example of one embodiment of the sheet
material in accordance with this invention. Specifically, there is
illustrated, generally indicated by reference numeral 10, sheet
material made up of a layer 15 composed of inorganic fibers 11,
such as asbestos fibers, upon which is precipitated an elastomer
latex 12, such as neoprene latex. Within layer 15 made up of
inorganic fibers 10 and precipitated latex 12 there is
substantially uniformly dispersed therein finely divided metallic
material 14, such as powdered lead, having a particle size smaller
than 200 mesh. This flexible coherent layer 15 has applied on one
surface thereof layer or coating 16 of pressure-sensitive adhesive
material. Desirably, for handling purposes, there is applied to
layer or coating 16 a protective or peelable top coating 17 of
paper, plastic film or other material which readily strippable,
such as by peeling, from pressure-sensitive adhesive layer 16. The
other side or surface of layer 15 has applied thereto coating or
layer 18 of weather resistant or water-proof material, such as
bitumen or tar. If desired, coating or layer 18 may be replaced or
have applied thereto a decorative type film, such as a decorative
plastic film, e.g. Mylar decorative film, or a polyvinyl chloride
or polyolefin decorative film, e.g. polyethylene or
polypropylene.
In the use of the illustrative sheet material 10 as a sound
deadening or vibration dampening material, with the lead content of
the layer 15 comprising about 70-80% thereof, strippable protective
coating 17 would be removed from a measured length of the sheet
material 10 and the resulting exposed pressure-sensitive layer 16
would be applied directly to the surface to be protected or
affected, such as to block radiation, to prevent or reduce sound
transmission or vibration therethrough. There would be exposed
surface 18 which could, as indicated hereinabove, be a
water-resistant or weather-resistant coating, such as bitumen or
tar or, for decorative or indoor purposes a decorative plastic
film.
In the manufacture of the sheet material of this invention
employing conventional paper or sheet-forming equipment, such as
equipment useful for the manufacture of sheet asbestos, there is
formed a watery admixture or furnish made up of the fibrous
materials, such as asbestos fibers, and the elastomer latex, such
as an acrylonitrile-butadiene latex, e.g. Buna-N latex, with the
wetting or wetting down of the fibrous material in the water,
preferably with the aid of a wetting or dispersing agent, such as
an anionic surfactant, such as Darvan, a sodium salt of polymerized
alkyl naphthalene sulfonic acids or sodium salts of polymerized
substituted benzoid alkyl sulfonic acids or aryl alkyl sulfonic
acids, e.g. Darvan No. 6 manufactured by R. T. Vanderbilt Co., New
York, N.Y. The finely divided metallic or inorganic material is
then added, such as finely divided powdered lead having a particle
size smaller thatn 200 mesh. After agitating the resulting liquid
admixture or furnish made up of asbestos fibers, elastomer latex,
lead and dispersing agent, precipitation of the latex onto the
fibrous material, such as the asbestos fibers, and to some extent
onto the finely divided powdered inorganic material takes place,
usually within about 5 minutes. Desirably, a trace amount of an
aqueous calcium chloride solution, 10% by weight CaCl.sub.2, is
added to effect complete precipitation and clarity in the watery
admixture.
The resulting watery admixture now containing the ellastomer latex
substantially and completely precipitated onto the fibrous material
is heated, such as to a temperature in the range
100.degree.-150.degree.F., e.g. about 130.degree.F., and pumped or
agitated for a short time, such as for not more than a few minutes,
e.g. about 10-60 seconds. The resulting watery admixture or furnish
is then flowed onto or discharged onto a paper-making screen or
surface.
Upon discharge of the watery admixture to the paper-making screen
or surface the asbestos fibers become at least partly felted and
adhered together by the elastomer coating. The elastomer latex
coating also serves to entrap or entrain the finely divided or
powdered inorganic or metallic material, such as finely divided
lead, together with the fibrous material with the result there is
formed a substantially uniform and homogeneous sheet material
consisting essentially of the fibrous material, elastomer latex and
the finely divided or powdered inorganic or metallic material is
substantially the same proportions or relative amounts as orginally
employed in the make-up of the above-described watery
admixture.
After the formation of the sheet material on the screen or
sheet-forming surface it is removed, desirably after water has been
expressed therefrom, such as by passing in contact with a pressure
roll, and the resulting sheet material now having a reduced water
content, below about 10-20% by weight, is dried by wrapping around
heated "can" or drums or by tunnel drying, such as by passing the
resulting sheet material through a tunnel in contact with heated
air at a temperature in the range 120.degree.-250.degree.F., more
or less. Upon drying the sheet is passed through a calendering
operation and there is produced a flexible, coherent substantially
limp material having a substantially reduced, less than about 1% by
weight, water content.
A number of sheet materials in accordance with this invention were
prepared generally in accordance with the above-described
procedure. The formulation, make-up, properties and procedure for
the manufacture of these sheet materials are set forth hereinbelow
in the accompanying tables.
TABLE NO. 1
__________________________________________________________________________
FORMULATION 1 2 3 4 5 6 7 8 Composition lbs. lbs. lbs. lbs. lbs.
lbs. lbs. lbs.
__________________________________________________________________________
Bleached sulfite 9 9 9 9 -- -- Asbestos fibers 21 21 21 21 30 30 30
30 Anionic surfactant (dispersant) No. 6 Darvan, a surfactant manu-
factured by R.T. Vanderbilet Co. Inc. 0.06 -- -- -- 0.06 0.06
Acrylonitrile- butadiene latex, BUNA-N, TN-4105A (dry) 10.2 10.2
10.2 10.2 -- -- 10.2 -- Neoprene latex Neoprene 450 (dry) -- -- --
-- 10.2 10.2 -- 10.2 10% by weight aqueous calcium chloride solu-
tion trace trace trace trace trace trace trace trace Lead, particle
size -200 mesh 5.1 51.0 102 204 102 204 102 102 Drainage-seconds
0.9 0.9 1.1 0.9 3.2 9.0 Pressure (tons) 13 20 10 10 10 10 Caliper
(thick- ness) inch 0.0385 0.0417 0.0529 0.061 0.054 0.068 Tensile
lbs. pull 59 53 41 33 -- -- Tensile psi 1475 1226 733 490 -- -- %
by weight rubber (total solids) 22.7 11 7.2 4.2 7.2 4.2 % by weight
lead (total solids) 11 55 72 85 72 85 72 72
__________________________________________________________________________
TABLE NO. 2
__________________________________________________________________________
9 10 11 12 Furnish Grams Grams Grams Grams
__________________________________________________________________________
Asbestos fibers 40 40 40 40 Polyvinylchloride latex (dry basis) 12
12 -- -- Neoprene latex (dry basis) -- -- 12 12 Powdered lead 120
120 120 120 Santo-white -- -- 1.2 1.2 Calcium chloride (10%
solution) 10 ml. 10 ml. 15 ml. 15 ml. Pulping time (seconds) 14 14
14 14 Consistency (%) 3 3 3 3 Precipitation Temp. .degree.F. 80 80
80 80 Drainage Temp. .degree.F. 100 100 100 100 Caliper (inches)
0.0560 0.0584 0.0553 0.0562 Weight 6".times.6" (grams) 90.88 97.4
103.6 102.3 Weight 500 ft..sup.2 (lbs.) 400.23 428.94 456.25 450.52
Density (lbs./cu.ft.) 171.52 176.27 198.01 192.39 Tensile (lbs.
pull) 32.5 44.5 57.25 61.75 Tensile (psi) 575 723 1133 1199
Drainage (seconds) 0.85 0.95 2.4 1.9 Wire Release Ex Ex Ex Ex
Precipitation time (minutes) 25 23 10 22 Lead settling 0 0 trace
trace
__________________________________________________________________________
In the preparation of the sheet material in accordance with this
invention employing the formulations indicated in Tables Nos. 1 and
2 and following the procedures described hereinabove, it was
observed that no lead or only trace amounts of lead were found in
the drainage. All formulations had excellent wire release from the
sheet-forming screen.
Sheet materials in accordance with the above-described technique
and made up of neoprene as the elastomer latex and Buna-N as the
elastomer latex and containing 72% by weight powdered lead were
very flexible and had a density about 155-159 lbs./cu.ft. and
weight 53 lbs./100 ft..sup.2 at 0.041 inch thickness.
The sheet materials prepared in accordance with the above
formulations and procedures or techniques have a wide utility and
permit a wide range of formulation. For example, and particularly
useful as vibration dampening or radiation shielding, sheet
materials consisting essentially of powdered lead, asbestos and
elastomer latex are readily prepared. Such materials would resist
acid and alkali attack, would tend not to become brittle on
weathering, would resist cold flow and flow at elevated
temperatures, would exhibit good flexibility for easy installation
and, as indicated hereinabove, could readily be prepared in various
thicknesses. Because of the above-indicated physical properties
sheet materials prepared in accordance with this invention would be
usefl as radiation shielding materials for use in connection with
radar cooking equipment, x-ray equipment, instrument shielding,
radioacative clean rooms, television sets and pipe wraps,
especially wraps for pipes containing radioactive materials. These
materials would also be useful as noise deadening material, useful
for sound insulation with respect to walls, roofs and doors, such
as by being laminated to or fixed to doors and walls or enclosures
of rooms containing compressors, pumps, generators, engines, as
well as for insulation in submarines to prevent noise leakage and
for use in vibration dampening, e.g. in connection with natural gas
transmission lines, particularly on lines in close proximity to
compressor stations. The materials of this invention would also be
useful as gasketing materials. The materials of this invention
would also be readily useful as specialized roofing material and
the like, for use in connection with outdoor installations and the
like.
As will be apparent to those skilled in the art in the light of the
foregoing disclosure, many modifications, alterations and
substitutions are possible in the practice of this invention
without departing from the spirit or scope thereof.
* * * * *