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International Hydrolytics Ltd. |
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United States Patent |
4,263,048 |
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Hacker |
April 21, 1981 |
Self-hardening composition and composite therefrom
Abstract
A self-hardening composition
consists essentially of 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
fluorosilicate, 30-40% by weight of sodium silicate, 0.02-0.04% by weight of aluminum
silicate clay and water. Composites made therefrom can include expanded
aggregate material and/or reinforcing fibers, as extenders, or to impart
control over the open curing time to preset requirements.
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Inventors: |
Hacker; Dennis J. (Albuquerque, NM) |
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Assignee: |
High Efficiency Insulation Technologies, Inc. (Albuquerque, NM) |
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Appl. No.: |
115544 |
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Filed: |
January 25, 1980 |
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Current U.S. Class: |
106/601; 106/602; 106/632; 428/453 |
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Intern'l Class: |
C04B 019/04 |
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Field of Search: |
106/74,84,85 428/453 |
References Cited
U.S. Patent Documents
|
3138471 |
Jun., 1964 |
Wygant |
106/84. |
|
3203813 |
Aug., 1965 |
Gajardo et al. |
106/84. |
|
3450548 |
Jun., 1969 |
Petkus |
106/84. |
|
3483006 |
Dec., 1969 |
Vassilevsky et al. |
106/84. |
|
3508936 |
Apr., 1970 |
Lyass et al. |
106/84. |
|
3837872 |
Sep., 1974 |
Conner |
106/84. |
|
3874887 |
Apr., 1975 |
Dalmatov et al. |
106/84. |
|
3933514 |
Jan., 1976 |
Banks et al. |
106/84. |
|
4030939 |
Jun., 1977 |
Mallow |
106/84. |
|
4066463 |
Jan., 1978 |
Chollet |
106/74. |
|
4138268 |
Feb., 1979 |
Vogel et al. |
106/84. |
Primary Examiner: Poer; James
Attorney, Agent or Firm: Cyr; Frank
P.
Claims
What is claimed is:
1. A self-hardening composition consisting essentially of 3-5% by weight of an
alkaline earth metal chloride, 0.5-1.5% by weitht of calcium metasilicate,
0.5-1.5% by weight of sodium fluorosilicate, 30-40% by weight of sodium
silicate, 0.02-0.04% by weight of aluminum silicate clay and water.
2. The composition of claim 1, wherein the alkaline earth metal chloride is
CaCl2.MgCl.sub.2.
3. The composition of claim 1, wherein the aluminum silicate clay is kaolin.
4. The composition of claim 1, wherein the amount of sodium silicate is 35-39%
by weight.
5. The composition of claim 4, wherein the ratio Na.sub.2 O:SiO.sub.2 is
1:1.65-3.9.
6. The composition of claim 1, wherein the alkaline earth metal chloride is
CaCl2.MgCl.sub.2, the aluminum silicate clay is kaolin, the amount of sodium
silicate is 35-30% by weight, and the molar ratio Na.sub.2 O:SiO.sub.2 is
1:1.65-3.9.
7. A self-hardening composite material comprising 10-35% by weight of the
composition of claim 1, admixed with an expanded aggregate material or
reinforcing fibers.
8. A laminate comprising a composite of claim 7, firmly adhered to a facing
sheet.
9. The composite material of claim 7, wherein the expanded aggregate material
is cellular perlite, vermiculite, cellular glass, expanded slag, cellular
diatomite, or cellular pumice.
10. The composite of claim 7, wherein the reinforcing fiber is fiberglass or
mineral fibers.
11. The composite of claim 8, wherein the reinforcing fiber is fiberglass or
mineral fiber and the expanded cellular aggregate material is cellular perlite,
vermiculite, cellular glass, expanded slag, cellular diatomite, or cellular
pumice.
Description
BACKGROUND OF THE INVENTION
Many adhesives and bonding compounds in present use are derived from
petrochemical 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 compositions which will withstand extreme
temperatures are kiln dried, fired or otherwise subjected to external heating
to achieve satisfactory bonding, e.g., fired bricks, tiles, etc.
Vassilevsky et al, in U.S. Pat. No. 3,483,006, describe a cold-curable
cementitious composition composed of MgO or semi-calcined dolomite, magnesium
sulfate, an alkaline earth metal chloride (XCl.sub.2), an alkali metal silicate
(Y.sub.2 SiO.sub.3) and an alkali metal fluorosilicate (Y.sub.2 SiF.sub.6). The
cement comprises two complex substances: a Mg(Ca)-oxychloro-sulfate and the
combination of XCl.sub.2 -Y.sub.2 SiO.sub.3 -Y.sub.2 SiF.sub.6.
Gajardo et al (U.S. Pat. No. 3,203,813) disclose 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.degree.-400.degree. F. to set the silicate.
Lyass et al (U.S. Pat. No. 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.
Other references on siliceous cement or concrete products include:
U.S. Pat. Nos. 3,138,471, Wygant; 3,450,548, Petkus; 3,837,872, Conner;
3,874,887, Dalmatov et al; and 4,030,939, Mallow.
OBJECT OF THE INVENTION
It is an object of the invention to provide a composition for insulating
materials made by cold mixing various components to make a bonding compound
that can be intermixed with particulate fillers such as expanded perlite,
fiberglass, 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 a self-hardening
composition consisting of 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
fluororsilicate, 30-40% by weight of sodium silicate, 0.05-0.04% by weight of
aluminum silicate clay and water.
In a further compositional aspect of this invention, self-hardening composites
comprise 10-35% by weight of the foregoing composition, admixed with an
expanded aggregate material or reinforcing fiber.
DETAILED DESCRIPTION
"Alkaline earth metal chloride," as used in the specification and
claims, means MgCl.sub.2 or CaCl.sub.2 or a mixture thereof, preferably a 1:1
mixture thereof, represented by the formula CaCl2.MgCl.sub.2.
Calcium metasilicate is represented by the formula CaSiO.sub.3, whether in the
.alpha.-(pseudowallastonite) or .beta.-(wollastonite) form.
Sodium fluorosilicate, silicofluoride or hexafluorosilicate is represented by
the formula Na.sub.2 SiF.sub.6.
"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 Na.sub.2 SiO.sub.3 and is also known as
water glass or sodium metasilicate. Sodium silicate includes products having
various ratios of Na.sub.2 O:SiO.sub.2. Typically, in the practice of this
invention, sodium silicate is used in the form of a solution in which the
SiO.sub.2 :Na.sub.2 O molar ratio is 1.65:3.9. Preferred sodium silicate with a
specific gravity of 1.387 at 499.3 per liter. Solutions of sodium silicate used
in the practice of this invention will contain about 30-40% of solids, i.e.,
solutions of above approximately 34.degree. Baume will be used. Most
preferably, the bonding compositions of this invention will contain 35-39% by
weight of sodium silicates. Therefore, sodium silicate solutions above
approximately 39.degree. Baume 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 68.4.degree. F. 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. Rule of thumb is 30 minutes at 60.degree.
F. 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 mm at 18 lb/ft.sup.3 will come out at 0.04-0.06 W/m.degree. C., or
better. Low temperatures range down to minus 100.degree. C., 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/in.sup.2. At the
end of 1/3 hour, curing is complete as indicated by surface hardness.
Because the compositions of the invention are self-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 combined with sodium silicate solution.
In preferred embodiments, 10-35% by weight of the bonding composition is
extended with an expanded aggregate material and/or reinforcing fiber material
to provide fire-retardant lightweight air-curable composites.
"Expanded aggregate material," as used in the specification and
claims, includes, but is not limited to, cellular perlite, vermiculite,
cellular glass, expanded slag, cellular diatomite and cellular pumice. However,
the foregoing are preferred, most preferably expanded or cellular perlite and
cellular diatomite.
Reinforcing fibers include, but are not limited to, organic fibers and
fiberglass. Fiberglass is preferred owing to resistance to combustion. Organic
fibers include natural fibers such as cellulose and wood fibers and synthetic
fibers, e.g., from 1/2 to 11/2 inches in length.
In the practice of the invention, the filler being bonded is mixed with the
cold self-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.
Structured end products with densities of 10 to 39 lb/ft.sup.3 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 21/2-111/2 lb/ft.sup.3 (40-180 kg/m.sup.3), although
aggregates having densities of 51/2-111/2 lb/ft.sup.3 (90-180 kg/m.sup.3) 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 invention can, while the composites are in the form of a
paste of the required density, be formed, pressed or molded under varying
pressures between sheets to form double- or single-faced laminates. Either
facing sheet of the thus-formed laminate is of metal, cardboard, plastic,
fiberglass, paper or any other material which will adhere to the composite
material and which will dry and cure at ambient temperature. Preferred
laminates are those wherein the filler is fiberglass and the facing sheet is
metal or fiberglass.
DESCRIPTION OF PREFERRED EMBODIMENTS
With respect to the self-hardening composition of this invention, the most
preferred embodiment is that wherein the alkaline earth metal chloride is
CaCl2.MgCl.sub.2, the aluminum silicate clay is kaolin, the amount of sodium
silicate is 35-39% by weight and the molar ratio Na.sub.2 O:SiO.sub.2 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 skilled in the art can,
using the preceding description, utilize the present invention to its fullest
extent. The 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-HARDENING COMPOSITION
EXAMPLE 1
The following dry ingredients were mixed together by a rotary mixer:
______________________________________
Magnesium Calcium Chloride-CaCl.sub.2
:MgCl.sub.2
4
Calcium Metasilicate-CaSiO.sub.3
1
Sodium Fluorosilicate 1
Kaolin 1/32
______________________________________
To the resulting dry mix was added 93 31/32% by weight of commercial sodium
silicate solution (40.5.degree. Baume, Na.sub.2 O:SiO.sub.2 ratio 1:1.65-3.9.).
The mixture was stirred to a viscosity of 26 centipoise.
EXAMPLE 2
______________________________________
% 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.
EXAMPLE 3
______________________________________
% by weight
______________________________________
Fibers (Organic) 68-84
Diatomite 5-17
Bonding Compound of Example 1
23-35
______________________________________
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 product
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 the finger, gives a resonant solid sound.
EXAMPLE 4
______________________________________
% by weight
______________________________________
Expanded Perlite Particles
25-56
Organic Fibers 32-45
Bonding Compound of Example 1
18-29
______________________________________
A composite material was obtained as in Example 2.
EXAMPLE 5
______________________________________
% by weight
______________________________________
Expanded Perlite Particles
60-85
Fiberglass 5-12
Bonding Compound of Example 1
10-34
______________________________________
Composite material obtained as in Example 2 had the following characteristics:
a rigid lightweight (17-22 lb/ft.sup.3) dry-faced core material that had high
thermal insulation qualities. Non-hygroscopic with free moisture content
maximum 0.5%. Appearance: pearl white. Softening point: 900.degree.-1100.degree.
C., 1600.degree.-2000.degree. F. Fusion point: 1280.degree.-1350.degree. C.,
2300.degree.-2450.degree. F. Products structured from Examples 1, 2, 3, 5, 6, 7
were inert. Some unlaminated core material was made from Example 5, in
accordance with the present invention, in the form of dry panels with a
specific density of 27 lb/ft.sup.3) 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: 120 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 completely incombustible
and non-toxic when submitted to furnace temperatures of 2,000.degree. F. 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 foregoing examples relate to a rigid dry-formed panel, but, 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 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 known and natural insulation qualities and geodetic strengths that are
found in pre-expanded perlite particles of all grade sizes.
EXAMPLE 6
Composites containing up 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/ft.sup.3, and laminated on each face with aluminum foil, air-laid fiberglass
sheeting, etc.
EXAMPLE 8
Bonding material was made as in Example 1 from the following:
______________________________________
% by weight
______________________________________
Magnesium Chloride 4
Calcium Metasilicate 1
Sodium Fluorosilicate
1
Kaolin 1/32
______________________________________
To this dry mixture was added sodium silicate solution, 40.degree.-42.degree.
Be, the combination mixed to a viscosity of 26 centipoise.
Bonding material was formulated with expanded fillers and/or fibrous fillers as
in Examples 2-7. The behavior of 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, and, 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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