Note: Descriptions are shown in the official language in which they were submitted.
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6 BACKGROUND
8 This invention relates to a composite building module
9 which is similar to monolithic cast concrete modules in
outward appearance and use, yet has significant improvements in
11 insulating properties and weight reduction. More particularly,
this invention relates to a composite building module having
12 a rigid foam core, such as a rigid urethane polymer foam,
13 encased or encapsulated in a shell made of a hardened mixture
14 of cement and fibers, such as glass fibers.
- Because of increased costs in material and labor,
16 the construction industry has come to use prefabricated
17 building modules, for example wall panels, roof decks and the
like. A popular form of construction is known as "curtain-wall"
18 construction and involves the use of a struc-tural steel
19 skeleton which is faced with stacked-up, prefabricated or
precast panels. Such curtain-wall panels are commonly cast
21 from reinforced concrete and are provided with a surface finish~
22 such as a smooth concrete finish or aggregate imbedded into
23 the face of the panels. These panels are extremely heavy, for
24 example a 4 x 8 curtaln-wall panel cast from reinforced
concrete weights from 1400-1600 lbs., and require heavy con-
struction equipment ~o install. In addition, these panels ~;-
26 provide very poor insulating properties and by themselves are
a poor vapor barrier. This necessitates further construction ~ ~ -
2~ to insulate and seal the stacked-up curtain-wall of precast
~69Z6~
1 concrete modules.
2 The construction industry has long sought improved
3 building elements that will offer advantages in material and
4 construction costs. A laminated slructural element is described
Muhim paten~, U.S. 3>295,278, issued January 3, 1967, as
consisting of (i) a preformed plastic foam layer, (ii) one or
more covering layers of aqueous binding material hardened to
7 impart the strength required for a structure where the structural
element is to be used, and (iii) mechanical means in~erlocking
9 the foam covering layers into a unitary element. Heat
insulation is imparted by the plastic foam layer while the
11 required structural strengths are provided by the covering
layer or layers.
12 In one embodiment a preformed plastic foam layer
13 is sandwiched between two concrete layers which are connected
14 through openings in the foam layer by a multiplicity of
concrete dowels thereby interlocking the layers mechanically. In
16 another embodiment, a covering layer of a hardened cement
17 having a reinforcement of "wood fibers" therein is mechanically
18 interlocked by a multiplicity of "micro-dowels" formed by
the binder in surface crevices of the preformed plastic foam
19 layer. The so-called "wood-fibers" providing the micro-dowels
have a length of 35-50 cm (approximately 14-20 inches).
21 Another proposal for a laminated insulating panel
22 is. set forth in British patent 1,030,333 and involves a preformed
23 insuiating layer which is surfaced on one or both sides with
24 at least two layers of cement between which is embedded a
glass fiber fabric web. The insulating or core layer, which
can carry a statLc load, is made from a mixture of Portland
26 Cement, an aqueotls plastic dispersion, sand and a lesser
27 amount of waste :Eoam formed when foamed plastic parts are sawed.
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1~69263
1 The covering layers are made of similar mixture without sand
using greater amounts o~ waste foam.
3 A real L~roblem encountered in making laminated panels
4 using preformed plastic foam cores (e.g., polystyrene foam)
is the lack of adhesive bond between the core and the covering
layer. Muhim attempts to cope with this by providing a
mechanical interlock using dowels or micro-dowels to ~orm a
7 unitary element. He also contemplates an extra bonding film
8 to improve adhesion. In the British patent, the covering .
9 layers contain a binder which will provide a bond with the
insulating core. The use of like materials in both the core
11 and the covering layers makes this possible.
12 The present invention provides a monolithic-like
13 building module which is extremely light in weight as compared
to precast concrete panels for example, and which has greatly
14 improved insulating and vapor barrier properties per se.
15 Because the present invention utilizes an in situ foamed core, .
16 an adhesive interlock`between core and shell is formed which
17 is stronger than either material by itsel~. The chemical
18 foaming reaction that takes place, plus the fact that foaming
lg takes place in an enclosed shell under retention, results in
an overall intimate adhesive interlock and a prestressed
structure w~erein the shell is under tension and the core is
21 under compression. This means that the shell and core are
22 now united together into a monolithic-like structure that
23 ha-s far greater strengths (because of the overall adhesive
24 interlock) than prior laminated panels using preformed foam .
plastic cores, and, at the same time, is light in weight
and has e~cellent insulating and vapor barrier properties.
26
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SUMMARY
~ he monolithic-like composite building module of the
invention comprises a core of rigid foam, preferably a rigid
urethane polymer foam core completely encased in an enclosed
shell made o~ a fiber reinforced cement, said shell containing
from about 1 to 40% by volume of fibers, preferably 2 to 15% by
volume glass fibers, having a llength of from about 1/8 to about 1
inch, preferably from about 3/8 to about 1 inch, and being sub-
stantially uniformly distributed in a random fashion throughout
substantially the entire volume of said shell, said core being
formed within the enclosed shell by the chemical reaction of
components of a foamable polymer composition which is foamed
in situ under pressure to form an encased rigid foam core in-
timately adhesively interlocked, via the in situ foaming re-
action, over its entire surface area with the shell over its
entire interior area. The in situ foaming reaction under pre-
ssure results in a module with a rigid core under compression
and an encasing shell under tension.
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The e~terior of the shell can be provided with any
desired surface finish including aggregates such as stone or
marble chips embedded in one or more surfaces thereof and the
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module can be used in the same manner as precast concrete
modules, without, however the need for heavy construction eq-
uipment and further steps to impart insulating and vapor barrier
properties thereto. -
The composite building modules of the invention can be
made in one em~bodiment by forming an open supported shell made
of a hardened mixture of cement and fibers, preferably glass
fibers, introducing a foamable polymer, preferably a foamable
rigid urethane ploymer, into the open shell, closing the shell
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- 1 with a cover member (made of a hardened mixture of cement and
2 fibers) before the polymer begins to foam, or before the
3 foaming polymer fills the open shell, and thereafter supporting
~ and holding the shell and cover member in place while polymer
foam fills the interior of the enclosed shell.
Because the shell is enclosed, foaming within the
6 interior takes place under pressure and this, plus the chemical
7 foaming reaction, contribute to the formation of the adhesive
8 interlock between the core and the shell and the creation of
9 a prestressed structure. In situ foaming within the enclosed
shell involves restraint during the act of foaming which is a
11 dynamic, expansive operation. The force of expansion causes
12 the foam to penetrate the pores of the reinforced cement shell.
The phrase "adhesive interlock" is used herein to describe this
13 and will be understood as the interfacial penetration of the
14 rigid foam core into the shell interior to unite the two into
a monolithic-like unit through a combination of mechanical,
16 chemical and adhesive forces.
17 In another embodiment, a rigid foam core, preferably
18 a rigid urethane polymer foam core, is encased in a shell
19 made from a hardened mixture of cement, preferably also con-
taining particulate inert fillers such as sand, and fibers,
, 20 preferably glass fibers, and the shell is formed in situ
21 around the core such that the mixture of cement and fibers
22 penetrates and bonds with the surface of the core providing a
23 positi~e interloc~ between the core and shell. The shell
24 contains from about 5 to about 50/o by vol~lme of reinforcing
fibers, having the- same length as described above, which are
substantially uniformly distributed in random fashion throughou~
26 substantially the entire volume of the shell.
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In accordance with one aspect of the present invention,
there is provided a process for making a monolithic-like, in-
sulated composite building module having a fiber-reinfo`rced, con-
tinuous and integral cement shell encasing a rigid foam core
which comprises, a) providing a mold having a bottom and side
walls, b) successively applying individual lengths of fibers ~-.. -.
and wet cement to the bottom of the mold, said fibers being
applied by chopping rolls of continuous fiber and spraying the
chopped fibers into the mold, c) substantially uniformly dis-
tributing the chopped fibers in a random fashion throughout the
entire volume of the wet cement applied in step (b) to form
a layer of wet cement and fibers in the bottom of the mold; d)
placing a rigid foam core member on said layer of wet cement and ~
fibers, said core member having a peripheral shape smaller than ::;
; the mold interior leaving a free space between the core member
and the mold side walls, said core member having a thickness
less than the height of the mold side walls; e) successively
applying individual lengths of fibers and wet cement to the top . :
of the core member and the free space between the member and the
mold side walls, said fibers being applied by chopping rolls
of continuous fiber and spraying the chopped fibers into the
mold, f) substantially uniformly distributing the chopped
fibers in a random fashion throughout the entire volume of the :.
cement applied in step (e) thereby encasing said core with a
wet ce~ent shell that is continuous, integral around the core
and fiber reinforced; and g) curing said wet cement shell and
removing the thus formed module from the mold.
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- 1 DESCRIPTION OF THE DRAWING
3 The present invention will be more fully understood
4 from the following description taken in conjunction witl~ the
accompanying drawing wherein;
6 Fig. 1 is a cross-sectional view of a typical
7 composite building module of the present invention;
Fig. 2 is a cross-sectional view partly in perspective
8 and partly broken away of a composite building module of the .
9 invention shown in the form of a highway barrier with a
weighted base;
11 Fig~ 3 is a perspective view partly broken away of
12 a partly assembled building illustrating various ways in which
the composite module of the invention can be utilized in the
14 construction of a building; and
Fig. 4 is a flow diagram for the process o the
invention.
16
17 DESCRIPTION
18
19 Pref~rred hardenable mixtures for the invention are
mixtures of cement, inert particulate filler and glass fibers
containing 5-50% or more by volume glass fibers. Mixtures of
21 cement and ibers with lengths o from about 1/8 to about
22 ~l~inch, or longer~ can be used in the invention. Suitable
23 ibers, in addition to glass ibers, include organic and
2~ inorganic synthetic fibers such as Dacron, l~ylon, graphite and
the like. Suitable inert particulate fillers include sand,
26 pumice, stone dusl:, and the like. They can be used in amounts
o rom about 10 t:o about 30% by volume.
27 The cement/fiber mixtures can contain conventional
28 additives such as lime and strates for water resistance and
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latex for added strength~
Suitable rigid foams include inorganic and organic
foams. Preferred are foams that can be formed in situ such as
rigid polymer foams. Rigid urethane foams are preferred and are
well-known and widely used principally for insulation purposes.
Such ~oams are commonly created on site by combining the reactants
(a polyol and an isocyanate) using a~ir-less spraying or liquid
application techniques. Foaming commences almost instantaneously
and is completed within a very short period of time, depending on
the type of urethane composition employed. The density of rigid
urethane foams also depends on the nature of the
urethane composition employed but generally ranges i ,
between 1.5 lbs. per cu. ft. to 10 lbs. per cu. ft., more ,'
commonly from 2 to 5 lbs. per cu. ft. Because of the lightweight - ' '
closed cell structure of rigid urethane foams, they also have
structural strength. Other suitable rigid foams include polyester
foams, phenol~c resin foams, isocyanurate foams, and the like.
The present invention combines a hardenable mixture ~'
of cement and fibers with rigid foams and provides a surprisingly
strong and self-supporting building module which is light in ~'
weight and has outstanding insulating and vapor barrier properties,~
The invention will now be described with reference to ','''
the drawing and the preferred embodiment of a rigid urethane foam
polymer core and a cement/glass fiber shell.
Fig. 1 of the drawing shows a typical building module
in cross-section and the component parts are shown in exaggerated
proportion~ for ease in understanding. Thus, the building module
of the invention has a rigid urethane polymer foam
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1 ~core 14 encased or encapsulated in a shell 12 made of a
2 ¦hardened mixture of cement and glass fibers. The finished,
¦monolithic-like module is indicated generally by the reference
4 ¦numeral 10. Fig. 2 shows a particular application wherein
¦the building module is in the form of a highway barrier
¦preferably having a weighted concrete base 16.
6 ¦ An important feature of the present invention is the
7 ¦ encapsulation of the rigid foam core 14 by the outer shell 12
8 ¦ and the formation of an intimate adhesive bond 11 between the
9 core 14 and the shell 12 preferably over the entire surface
area of the core 14 but depending on how the module is made,
11 the intimate adhesive bond can be formed over a major portion
12 of the interface between the core 14 and the shell 12. Because
the rigid foam core 14 is formed in situ, the foaming rigid
13 urethane polymer enters and fills surface-irregularities such
14 as pores and surface outlined glass fibers and provides an
intimate, preferably overall, rigid interfacial adhesive
16 interlock between the rigid foam core and the shell 12.
17 Dependlng on the intended use for the building module
18 of the invention, the shell 14 can have a thickness ranging ~ ;~
from about 1/8th in. to 1 in. or more. The thickness can be ~ :
greater or less than this range again, depending upon the -
ultimate use intended for the building module. For curtain-wall
21 panels, the shell 14 preferably has a thickness of from 1/4 in.
22 to 3/8 in.
23 Likewise, the rigid foam core 14 can range in
24 thickness from about 1 in. to 10 in. or more and this can be great~
25 or less depending on the structure involved and the intended -
.use. The buildin~ modules themselves can be made in almost
26 any size ranging :Erom small modular units up to relatively
27 large curtain wall units or roof deck members.
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l Fig. 3 shows just a few of the many ways in which
2 the building module of the invention can be employed. Because
3 building modules of the invention are like monolithic
4 modules in outward appearance and use, yet self-insulating, the
5 modules of the invention can be used in the same fashion using
6 the same construction and installation techniques as monolithic
concrete modules. Thus, the composite module of the invention
10 can be used as a wall panel or roof deck member as shown
in Fig. 3. The wall panels can be provided with window openings
9 as in panels 18 and 22 or door openings as per panel 20. The
modules of the invention can also be used as interior
ll partition wall panels 24 as well as other numerous uses.
Because of the light weight of the module of the invention,
12
great savings can be realized in the load bearing structure of :
13 buildings. Thus, for example, in a multi-story, curtain-wall
14 building, considerably less structural steel will be needed to
support the exterior panels as compared to the structural steel
16 required to support precast concrete panels. -
17 The facing surfaces of the composite panel 10 can -
18 be provided with any finish, texture or design which can
l9 be imparted via the finish or design of the mold surfaces or by
imbedding or adhering aggregate such as gravel, broken stone,
marble chips and the like to one or more surfaces of the
21 shell 12. It is also possible to incorporate aggregate such
22 as sand, gravel, broken stone and marble chips into the mixture
23 of cement and gl.ass fibers before forming the shell 12 for
~24 increased strength and also to attain desired surface textures
or finishes.
26 The composite building module as shown for example
in Fig. 1 can be made by forming an open supported shell 12
27 having a bottom and side walls and open at the top. A wooden
28 form can be built up to define one face and the side and end
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1 walls of a 4' x 8' panel and a trowelable mixture of cement and
2 35-45% by volume glass fibers can be applied by hand to
3 the interior surfaces of the wooden form thereby building up
4 the shell 12 to the desired thickness, for example, from
1/8th in. up to 1/2 in. thick or greater. The core 14 can
then be formed in situ using an air-less spraying technique
until the foam is built up to the top of the open shell. The
7 foam can then be trimmed and the remaining face of the panel 12'
8 applied by hand using the same trowelable cement/glass fiber
9 composition. Forming the building module in this ~ashion ensures
an intimate adhesive bond as described previously with the end
11 and side walls and one face of the shell. Because the core
is already formed when the completing face of the shell 12 is
12 applied, the adhesive bond is not as strong as the intimate
13 interfacial adhesive bond formed by in situ foaming of the
14 rigid foam.
It is preferred to introduce a flowable foamable rigid
16 urethane polymer composition into the open shell 12 and then
17 close or complete the shell with a cover member or panel 12' also
18 made of a hardened mixture of cement and glass fibers of the
19 desired thickness. The cover member 12' is applied before the
polymer begins to foam, or foaming fills the shell, and is
supported in back and held in place while the polymer composition
21 foams in the completely encased interior of the shell 12 thereby
22 -filling same and providing an overall rigid interfacial adhesive ~ -
23 interlocked between the rigid foam core 14 and the interior of
24 the shell 12 and cover 12'. As is known, a liquid or flowable
urethane polymer compositon exerts an outward pressure when
26 caused to foam ~within a confined space such as the shell and
this can be used to advantage in the present invention to ensure
27 and promote an intimate overall rigid interfacial interlock
28 between the entire exterior surface area of the rigid foam core
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~ 1 14 and the entire interior surface area of the shell made of a
hardened mixture of cement and glass fibers and create a stable
3 struc~ural stress throughout the module.
4 A preferred method for rnaking the composite building
modules of the invention will now be described with reference
to Fig. 4 of the drawing. At a f:irst station, metal or glass
~- fiber/polyester molds, preferably with fold down ends to
7 facilitate product removal, in the form of tops and bottoms,
8 have applied thereto a mixture of cement and glass fiber
9 perferably containing 35-40% by volume glass fiber. The mixture
of cement and glass fiber can be premixed dry and water subse-
quently added to provide a viscous mixture. This mixture can
11 then be sprayed into the mold interiors or applied by hand.
12 In a preferred embodiment, hot wet cement (made with
13 water at about 120-200F, e.g., 180F) without glass fi~er is
14 applied to or sprayed into the interior of the molds which
already has a lining of glass fiber chopped from continuous
16 rolls and sprayed or applied to the interior of the molds. The
17 molds can the be vibràted to disperse the lighter glass fibers
through the wet cement to obtain uniform distribution throughout
18 the entire volume of the cement layer in the molds. Because the
19 glass fiber is lighter, it rises in the wet cement; vibration
is stopped when distribution is complete. Following this, or
` 21 at the same time, the mixture of glass fiber and cement in the
22 molds can be pressed with a forming member to distribute the
23 cement/glass fiber mixture within the interior of the molds.
Z 24 Also, if desired, suction can be applied to the mold walls to
remove water.
At the same time the glass is chopped and sprayed, a
26 coating can be applied thereto by spraying, for example, with
27 a polyester in a water miscible solvent such as alcohol, to :
28 impart alkali resistance to the fibers.
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1 The molds are then fed to a curing line. If hot
cement is used, oven curing can be eliminated. Oven curing
3 genera]ly requires about 6 hours to produce a hardened shell
4 for the glass iber reinforced cement tops and bottoms; curing
S time for hot cement is generally 50% less.
Next, with the hardened bottom portion of the shell
still supported by its mold, a flowable, foamable rigid urethane
7 polymer composition is poured into the open shell and the top
8 is then set in place before substantial foaming begins. The
9 top can be removed from its mold at this point or it can
continue to be supported by the mold. With the top in place, the
11 moid supported assembly is then held under pressure while the
urethane polymer foams and sets. This can be accomplished using
12 a hydraulic plated press or other restraint device.
13 After the urethane polymer foam sets, filling the
14 shell and providing an overall rigid interfacial adhesive -;
lS interlock betwe`en the rigid foam core and the interior of
16 the shell, the panel is renoved from the bottom mold and the
17 top mold (if not previously removed).
18 After removing the mold or molds, the composite panel
19 is ready for use or can have a surface finish applied. Pre- ~ ~
ferably, the surfaces of the panel have applied thereto, using ~ `
electrostatic coating techniques for example, a sealer, such
21 as a polyester type of sealer. I~hile the panel itself is
22 -s~bstantially water proof, the application of a sealer insures~
23 that the panel will maintain its water proofness. If desired,
24 in addition to or in place of a sealer, the panel can be
painted, stained or other types of coatings can be applied,~for ; -
26 example, to provide for easy removal of graffiti. It has
also been found that a sealer, when applied in a thick coating,
27 can also be used to adhere aggregate to a surface of the panel ~ ~ -
28 to provide a surface finish. ` ;
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Modules with pre-formed cores can be made by placing
an insert or blank member which approximates the top area of a
panel into the bottom of a mold of desired configuration, such
blank being smaller in peripheral shape than the mold. A core
member of polyurethane foam is then placed on top of the blank,
such a core having approximately the same shape as the blank,
that is, smaller than the mold interior. A wet mixture of cement
and 1% to 4~O by volume glass fibers is then applied (preferably
hot, e.g., 120-200F) to the top and four sides of the core. After
curing the mold is removed, the semi-finished panel is inverted
and the blank is removed. The top of the panel is then formed
by filling in the blank space with the same wet mixture followed ~-
~by curing. In forming the top of the shell (where the blank was)
it is important that the wet cement/glass mixture extend from the
top down over the already formed sides. This insures that a good
bond will be ~ormed between the earlier formed shell and the
top thereof which is due to the fact that the reinforcing function
of the glass fibers is brought into play in this fashion. The
` extension down over the sides can be done by troweling; the ex-
tensions over the sides is generally one, two or more inches and
tapers down to a feather edge from a thickness of about 1/~ to
1/2 the shell thickness~
A preferred alternate to the foregoing is to apply a
layer of wet mixture of cement and 1% to ~0% by volume glass
fibers to the bottom of the mold, layin~ in a foam core which is -
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smaller than thle mold interior, applying the same wet mixture
down into the side spaces and the top and then vibrating the
::
entire assembly. Glass fibers can be put into the mold first
~u9ing only wet cement) before applying the bottom layer, then
down the sides and on~o the top of the core before applying theremaining cement. Vibration causes the lighter fibers to rise
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1 in the wet cement and thereby become evenly distributed
2 throughout the shell.
3 In the embodiment of Fig. 1, the juncture between
4 the open shell 12 and the cover or top 12' can be formed at
roughly 45 angles as shown, or any combination of right-angles
can be employed, including a set-in or overlapping configuration.
6 Where the two members 12 and 12' come together as shown in
Fig. l, the mating edges can be formed to leave a slight gap
8 so that foaming polymer can enter therein during the foaming
9 operation.
Many modifications can be made in the composite
11 building modules of the invention without departing from the
12 spirit and scope hereof. For example, the rigid foam core 1
13 can be reinforced utilizing woven or non-woven screen and
mesh layers made of synthetic fibers or metals and prestressing
14 techniques can be employed if desired. As mentioned previously,
15 one or more exterior surfaces of the shell 12 can be provided ~:
16 with any desired finish, texture or design or can be embedded
17 with inorganic aggregates such as gravel, broken stone, marble
18 chips and the like. As for surface design and texture, the -
19 exterior of the shell 12 will conform to the finish of the
mold surface to achieve desired effects, for example, a wood ~;
grain appearance and the like. The shell 12 can also be formed
21 with molded-in mounting or building clips and/or grooves. ~ .;
22 - As ment.ioned previously, the composite building ..
23 module of the invention can be used and installed in the same
24 manner as conventional building modules such as curtain-wall
panels but with a great reduction in weight (and simplified
26 installation procedures). Because of the greatly improved ;
insulating and water vapor barrier properties of the modules
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- 1 of the invention, no further steps have to be taken to
ensure these properties as is the case with conventional
3 building modules.
4 In roof deck installations or curtain-wall installations
a room temperature curing elastomer such as a silicone
6 elastomer can be used for edge to edge bonding between
adjacent modules and the entire installation can be provided
with an overcoating of a suitable elastomer. This provides
8 for a shock resistant installation which can also compensate
9 for later movement of a structure, for example, as a building
10 settles after construction. -
11 Because the composite building modules of the
12 invention are extremely light as compared to conventional
13 monolithic cast concrete modules, fewer structural members are
14 necessary for supporting, for example, a curtain-wall made of
panels of the present invention and a roof deck made of panels
of the presènt invention. For example, a 4' x ~' precast
16 concrete module weighs from about 1400-1600 lbs., whereas a
17 comparable composite module made according to the invention
18 weighs only about 100-150 lbs. depending on the thickness of
19 the shell 12. Thus, great savings can be realized in not
only installation procedures but also in the streng~h require-
21 ments for the supporting superstructure.
In addition to the uses illustrated in Figs. 2
22 an-d 3 of the drawing, the composite module in the invention can
23 be formed into insulated pipes and conduits, railroad ties,
2~ modular walls and even load bearing modular panels which can
incorporate conduits for utilities, window frames, door ~rames
and the like. It should also be noted that the composite
26
building panel of the invention is buoyant because of the
rigid foam core 14 which property can be utilized to advantage
28 in the construction of floating docks and wharfs as well as
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- 1 offshore drilling platforms.
2 It is known that a 1/8th in. or 1/4 in. coating of a
3 hardened mixture of cement and glass fibers gives acceptable
4 fire ratings to the underlying coated base. Thus, in a
preferred embodiment of the invention, rigid urethane polymer
foams are provided with acceptable fire ratings by forming a
6 laminate of a layer of rigid urethane polymer foam with an
outer covering layer made of a hardened mixture of cement
8 and glass fibers.
9 Foamable urethane compositions forming rigid urethane :
polymer foams are commercially available in a wide range o~
11 chemical and physical properties. Such compositions generally
12 contain an isocyanate component containing reactive isocyanate
groups, a polyol component containing one or more polyols,
13 catalytic agents and preferably a flame or fire resistant agent
14 such as trichloromomo1uoro methane. Typical properties of
rigid urethane polymer foams available commercially are set
16 forth in the following table:
17 TYPICAL RIGID URETHANE FOA~I PROPERTIES
.
18 Compressive Compressive
IDensity Strength Modulus Shear Shear
19 llb./cu.ft. psi psi Strength Modulus
¦Astm D 1622 Astm D 1621 Astm D 1621 psi psi
20 11.5-2.0 - 20-60 400-2000 20-50 250-550
21 12.1-30 35-95 800-3500 30-70 350-800
22 3.1-45 50-185 1500-6000 45-125 500-1300
23 4.6-70 100-350 3800-12,000 75-180 850-2000
~ 24 7.1-10.0 200-600 5000-20,000 125-275 1300-3000
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25 Suitable foamable urethane ~ompositions are sold by ~ :
26 Witco Chemical Co~rporation, New Castle, Delaware, and by Owens-
27 Corning Fiberglas Corp~, Toledo, Ohio
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