Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF T~lE INVENTION
Many adhesives and bonding compounds in pre.sen~ use
are derived from pe-trocnemical or organic sources. These
materials can emit toxic products or ignite in a fire, often
resulting in ignition or degradation of particles bonded
therewith to form further toxic products, exposure to which
can be fatal in confined spaces.
Other bonding compounds adapted for composltions which
will withstand extreme temperatures are kiln dried, fired or
otherwise subjected to external heating to achieve satisfac-
tory bonding, e.g., fired bricks, tiles, etc.
Vassilevsky et al, in U.S. Patent 3,483,006, describe a
cold-curable cementitious composition composed of MgO or
semi-calcined dolomite, magnesium sulfate, an alkaline earth
metal chloride (XC12), an alkali metal silicate (Y2SiO3) and
an alkali metal fluorosilicate (Y2SiF6). The cement comprises
two complex substances: a Mg(Ca)-oxychloro-sulfate and the
combination of XC12-Y2SiO3-Y2SiF6.
Gajardo et al tU.S. Patent 3,203,813) discloses an
insulating material containing an aluminosilicate clay, a
water-soluble alkali metal silicate, a foaming agent and an
expanded siliceous inorganic aggregate, heated at 300-400F
to set the silicate.
Lyass et al (U.S. Patent 3,508,936) obtain a self-
hardening mixture for foundry molds containing filler,
sodium silicate as binder, dicalcium silicate as hardener,
a foaming agent and an abietic resin to increase the
strength of the mold.
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Other references on siliceous cement or concrete products
include:
3,138,471 Wygan-t
3,450,584 Petkus
: 3,837,872 Conner
3,874,887 Dalmatov et al
4,030,939 Mallow
OBJECT OF THE INVENTION
It is an object of the invention to provide a composi-
tion for unsulating materials made by cold mixing variouscomponents to make a bonding compound that can be intermixed
with particulate fillers such as expanded perlite, fiber
gl~ss, mineral fibers or wools or diatomite to form a paste.
The paste can be molded, pressed or formed into structured
products using conventional machines. The bonded products
formed therefrom insulate against extremes of temperature but
lose no bond strength and emit no toxic fumes when subjected
to extreme heat or fires.
SUMMARY OF THE INVENTION
In a compositional aspect, this invention relates to
~ss~ ~;~/ly
a self-hardening composition consistinglof 3-5% by weight
of an alkaline earth metal chloride, 0.5-1.5% by weight of
calcium metasilicate, 0.5-1.5% by weight of sodium fluoro-
O ~
silicate, 30-40% by weight of sodium silicate, ~-4~r~ O- by
weight of aluminum silicate clay and water.
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In a further compositional aspect o -this invention,
self-hardening composites comprise 10-35% by weight o~ the
foregoing composition, admixed with an expanded aggregate
material or reinforcing fiber.
DETAIL~D DESCP~IPTION
"Alkaline earth metal chloride," as used in the speci-
fication and claims, means MgCl2 or CaCl2 or a mixture
thereof, preferably a 1:1 mixture thereof, represented by
the formula CaC12.MgC12.
Calcium metasilicate is represented by the formula
CaSiO3, whether in the d- (pseudowallastonite) or ~-(wollas-
tonite) ~orm.
Sodium fluorosilicate, silicofluoride or hexafluorosili-
cate is represented by the formula Na2SiF6.
"Aluminum silicate clay," as used in the specification
and claims, includes non-expanding clays, of which kaolinite,
halloysite, illite and attapulgite are exemplary. However,
kaolin is preferred.
"Sodium silicate," as used in the specification and
claims is generally represented by the formula Na2SiO3 and
is also known as water glass or sodium metasilicate. Sodium
silicate includes products having various ratios of Na2O:SiO2.
Typically, in the practice of this invention, sodium sili-
cate is used in the form of a solution in which the
SiO2:Na2O molar ratio is 1.65:3.9. Preferred sodium
silicate with a specific gravity of 1.387 at ~99.3 per litre.
Solutions of sodium silicate used in the practice of this
invention will contain about 30-40% of solids, i.e.,
solutions of above approximately 3~ Ba~ma will be ~sed.
Most preferably, the bonding compositions o this invention
will contain 35-39% by weight of sodium silicate8. There-
fore, sodium silicate solutions above approximately 39
Baumé will be used.
The self-hardening compositions of this invention are
made by combining the solid ingredients, for example, with
paddles or mechanically opposed rotating arms. To this is
added sodium silicate solution. Mixing is continued until
the product has an acceptable viscosity, preferably of the
order of 26 centipoise at 68.4F. If the bonding composition
is being used without fillers, the material is fabricated
into the desired shape and permitted to set under ambient
conditions. The time required for setting is dependent
upon ambient temperature and open time required. Kule of
thumb is 30 minutes at 60F ambient at which point the
product has the following characteristics:
Conductivity is subject to fillers used and end product
needs. As a rough guide, 25 m~ at 18 lb/ft3 will come out
at 0.04-0.06 W/mC, or better. Low temperatures range
down to minus 100C, or better, dependent upon known prior
specifics. The bonded product has a hard rigid set and
face. Natural color is pearl white. Crushing strength,
'~ without any other additions apart from perlite and bonding
compound, is 40 kg/in2. At the end of 1/3 hour, curing is
complete as indicated by surface hardness.
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Because the compositlons of the inven~ion are sel-
hardening, it will be understood that -the ingredients are
mixed just prior to use. If desired, -the solid ingredients
can be premixed and shipped dry. At the point of use, the
solid ingredients can then be com~ined with sodium silicate
solution.
In preferred embodiments, 10-35% by weight of the bond-
ing composition is extended with an expanded aggregate
material and10r reinforcing fiber material to provide fire-
retardant lightweight air-curable composites.
"Expanded aggregate material," as used in the specifi-
cation and claims, includes, but is not limited to, cellular
perlite, vermiculite, cellular glass, expanded slag, -;
cellular diatomite and cellular pumice. ~owever, the fore-
going are preferred, most preferably expanded or cellular
perlite and cellular diatomite.
ReinfGrcing fibers include, but are not limited to,
organic fibers and fiberglass. Fiberglass is preferred
owi~g to resistance to combustion. Organic fibers include
natural fibers such as cellulose and wood fibers and syn-
; thetic fibers, e.g.~ from ~ to l~ inches in length.
In the practice of the invention, the filler being
; bonded is mixed with the cold sel~-hardening bonding
composition to form a paste which is shaped by extrusion or
pressing at 7-40 psi or higher pressures to the required
shape, and predetermined product strength required.
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Structured end products with densities of 10 to
39 lb/ft may be obtained in this fashion.
The expanded aggregate material used in the practice
of this invention can have a particle size of from 150
microns to 4750 microns depending upon the specifications
of structured end product requirement. However, material
mesh of 2400-4750 microns is generally preferred. The
density of the expanded aggregate materials can be from
2~ lb/ft3 (40-180 kg/m3), although aggregates having
densities of 5~ lb/ft3 (90-180 kg/m3) are preferred.
Preferred sieve size of expanded perlite particles is
3000-6000 microns, with particle size (expanded) running
from 3 mm to 7 mm.
Addition of inorganic viscosity increasing agents,
- e.g., sodium silicate in solution at 1.387-4.864 pounds per
U.S. gallon to the basic bonding compound up to a level
of 10% by weight will extend curing time. The curing time
can be decreased by the addition of up to 8% by weight
of inorganic filler, e.g., kaolin, diatomatious earth,
fine mica, vermiculite, talc, etc. to the self-hardening
composition or composites made therefrom.
~` The process of mixing of the basic self-hardening
bonding compound and curing the products through stacking
~ and shipping of structured end products is therefore
-~; carried out without application of external heat for
drying or curing.
It will be understood that the composite materials
containing the self-hardening composition of this inven-
tion can, while the composites are in the form of a paste of
~2~25~
the required density, be formed, pressed or molded undex
varying pressures between sheets to for~ double- or single-
faced lamînates. Either facing sheet o~ the thus-formed
laminate is of metal, cardboard, plastic, iberglass,
paper or any other material which will adhere to the com-
posite material and which will dry and cure at ambiant
temperature. Preferred laminates are those wherein the
filler is fiberglass and the facing sheet is metal or
fiberglass.
DESCRIPTION OF PREFERRED EMBODI~IENTS
With respect to the self-hardening composi-tion of this
invention, the most preferred embodiment is that wherein the
alkaline earth metal chloride is CaC12.MgC12, the aluminum
silicate clay is kaolin, the amount of sodium silicate is
35-39% by weight and the molar ratio Na20:SiO2 is 1:1.65-3.9.
Of the composites prepared in accordance with the
invention, one which is particularly preferred is that
wherein the expanded aggregate material is cellular perlite,
vermiculite, cellular glass, expanded slag, cellular
diatomite or cellular pumice. Another particularly preferred
composite contains both one of the foregoing types of
aggregate and a reinforcing filler selected from fiberglass
or mineral fiber.
Without further elaboration, it is believed that one
s~illed in the art can, using the preceding description,
utilize the present invention to its fullest exten-t. The
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following preferred specific embodiments are, therefore,
to be construed as merely illustrative and not limitative
of the remainder of the disclosure in any way whatsoever.
In the following examples, the temperatures are set forth
uncorrected in degrees celsius; unless otherwise indicated,
all parts and percentages are by weight.
PREPARATION OF SELF-HARDE~ING COMPOSITION
EXAMPLE 1
The following dry ingredients were mixed together by a
rotary mixer:
~/O by weight
Magnesium Calcium Chloride-CaC12:MgC12 4
; Calcium Metasilicate-CaSiO3
Sodium Fluorosilicate
Kaolin 1/32
To the resulting dry mix was added 93 31/32% by weight
of commercial sodium silicate solution (40.5 Baume,
Na2O:SiO2 ratio 1:1.65-3.9.). The mixture was stirred to a
viscosity of 26 centipoise.
;.
EXAMPLE 2
/o by weight
Expanded Perlite Particles 63-90
Bonding Compound of Example 1 10-37
The particles to be bonded were first dry mixed
together by mechanically opposed rotating arms and then mixed
with the bonding compound in the cold state. The resulting
mass was stirred to a paste, which was shaped by application
of pressure from 15-38 psi into structural products.
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EXAMPLE 3
V!o by welght
Fibers (Organic) 68-84
Diatomite 5-~7
Bonding Compound of Example 123-35
The composite was mixed as in Example 2 and pressed
at 17 psi to obtain structural products, which cured at
ambient conditions within 1-3 hours to a produc~ having
the following characteristics: pearl white colored rigid
board with perlite particles shape clearly visible.
Capable to be handled and used, and, when tapped with finger~
gives a resonant solid sound.
EXAMPLE 4
/o by weight
Expanded Perlite Particles 25-56
Organic Fibers 32-45
Bonding Compound of Example l18-29
A composite material was obtained as in Example 2.
EXAMPLE 5
/O by weight
Expanded Perlite Particles 60-85
Fiberglass 5-12
Bonding Compound of Example 110-34
Composite material obtained as in Example 2 had the
following characteristics: a rigid lightweight (17-22 lb/ft3)
dry-faced core material that had high thermal insulation
qualities. Non-hygroscopic with free moisture content
maximum 0.5%. Appearance: pearl white. Softening point:
-10-
900-1100C, 1600-2000F. Fusion point: 1280-1350 C,
2300-2450F. Products structured from Examples L, 2, 3,
5, 6, 7 were inert. Some unlaminated core material was
made from Example 5, in accordance with the present inven-
tion, in the form o dry panels with a specific densi~y o:E
27 lb/ft3 (432 kg/m3) in 1.0 meter lengths as cold mixed
formed and cured panels. These panels were used to form a
dry board encasement fire protection cover for a structural
steel column and was submitted to a time and temperature
test curve of: British Standard 476, part 8 (1972~ in the
following categories:
Dry panels encasement at 50 mm (2 inches) thick with
no laminates either side:
Stability: 12~ min
Re-load: Satisfied
Fire resistance: 120 min
Dry panels encasement at 25 mm (1 inch) thick with no
` laminates either side:
- Stability: 60 min ;~
Re-load: Satisfied
~` Fire resistance: 60 min
Further tests showed that the foregoing panels were com-
pletely incombustible and non-toxic when submitted to furnace
temperatures of 2,000F for extended periods and not subject
to loss of bond when direct flame in the same temperature
range was applied to any face of the material for extended
periods.
The roregoing examples relate to a rigid dry-formed
panel, bu~, by the very nature of complete compounds and
aggregates and by the very low psi pressures required to
form a desired end product, it is possible to press and mold
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to any shape that is capable to be so produced from existing
plant and equipment with a modification being made to the
feed and pressure applied in order to retain the ~nown a~d
natural insulation qualities and geodetic streng~hs tha~
are found in pre-expanded perlite particles of all grade sizes.
EXAMPLE 6
Composites containing up to 55% of fiberglass (see
Example 4) had better load-bearing characteristics and
higher shear strength than those of Example 2.
EXAMPLE 7
Composites of the following compositions are prepared
as in Example 2:
/~ by weight
Expanded Perlite Particles: Large grade 63-74
Kaolin 4-7
Glass Fibers: one-inch long 1-5
Bonding Compound of Example 1 10-28
The products were structured as core materials having
a nominal density of 15-28 lb/ft3, and laminated on each
face with aluminum foil, air-laid fiberglass sheeting, etc.
EXAMPLE 8
Bonding material was made as in Example l from the
following:
/O by wei~ht
Magnesium Chloride 4
Calciu~ Metasilicate].
Sodium Fluorosilicate
Kaolin 1/32
- To this dry mixture was added sodium silicate solu~ion,
-12-
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40-42Be, the combination mixed to a viscosity of 26
centipoise .
Bonding material was formulated with expanded illers
and/or fibrous fillers as in Examples 2-7. The behavior o
products was similar.
The preceding examples can be repeated with similar
success by substituting the generically or specifically
described reactants and/or operating conditions of this
invention for those used in the preceding examples.
From the foregoing description, one skilled in the art
can easily ascertain the essential characteristics of this
invention, andt without departing from the spirit and scope
thereof, can make various changes and modifications of the
invention to adapt it to various usages and conditions.
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