Note: Descriptions are shown in the official language in which they were submitted.
1054869
The present inventi.on xelates to a method of and an appa-
ratus for foxming multiple~co~ponent composite str.uctures, :Such
stxuctures may include lam~nates having a plurality of distinct
layers~ each layer beàng composed to have different physical
properties, In addition~ such structures may be made having no
distinct interface, but having gradually changing material con-
stituents, or gradually changing material prOpQrtions. Particulate
and fibrous materials are mixed into catalyzed resin and the use
of particulate and fibrous material provides special physical and
chemical properties and sa~es expensive resins while imparting
such properties. This invention includes a method of and an appa-
ratus for providing a spray, including a plural component material
with a multiplicity of entrained filler and reinforcing materials,
and more particularly, includes an apparatus for and a method of
providing a commingled spray, including a plural component material
with granular material and with chopped fiber glass wetted by the
li~uid component prior to deposition.
Multiple~component composite structures which may be
formed with this invention include, for example, rigid laminates
including outer layers of one composite material and a central
layer or layers of other composite materials. The outer layer
can be composed to have one set of physical characteristics, such
as resistance to oxidation and ultraviolet light, high gloss and
color retention, hardness and other characteristics associated
~ith exterior surfaces. The central layer or layers can be com-
posed to have an entirely different set of physic~l characteristics,
such as lo~ dens~ity~ low. thermal conductivity, rigidity, low ther-
mal expansion, and good adhesion with the outer layers. With this
lOS486~
method and apparatus~ a rig~d structure can be economically and
quickly made haYin~ speci~ic physical properties not othexwise
available.
It is also feasible to use this method and apparatus
to pro~ide coatings upon a myriad of surfaces such as wood,
paperboard, plasterboard, polyester~based materials~ cement-based
or cement~impregnated paper materials and masonry exterior sur-
faces, including but not limited to brick, cement and stone. This
method and apparatus can reduce the cost of the coating, reduce the
weight of the coating, provide a surface with a coating having a
variable surface contour and various colors, and provide an ad-
herent coating with which mechanical fasteners may be easily used.
Plural component li~uid materials which may be sprayed
concurrently with granular and fibrous materials include polyester
resins, epoxy resins, urethane resins, silicone rubber and the like.
Generally, the plural component liquid material is converted, at
ambient atmospheric temperature, from a liquid to a solid by the
addition of an appropriate curing agent, which includes catalyst
materials. Polyester resins may be cured by the addition of an or-
ganic peroxide catalyst and a naphthenate or aniline promoter.Epoxies may be cured by the addition of a suitable amine or anhy-
dride curing agent. Urethanes may be obtained by the addition of a
suitable isocyanate ester to a polyol resin. Silicone rubber may be
obtained by the addition of a suitable tin soap to a silicone
elastomer.
The addition of the curing agent to the other plural com-
ponent liquid material is usually made just prior to use to thereby
initiate curing Gf the plural component material. Generally, the
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curing cycle of the plural component material is of short duration.
For example, upon the addition of bot~ a catalyst and a promoter,
pol~ester resin may solidify ~n a matte~ of 45 minutes or less.
The plural component materiaI can be mixed with granular
materials such as perlite, clay~ sand~ talc~ mica, aluminum hy~
drate, calcium carbonate, calcium silicate~ glass beads~ plastic
spheres, fire retardants and the like~ and with reinforcing fiber
glass or other fibrous materials. Such particulate and fibrous
fillers may provide any one or more of the following properties:
reinforcement of the resin rigidity, reduced shrinkage, economy in
the use of resin, low density and special properties such as fire
retardancy.
With the method and apparatus of this invention, higher
concentrations, as well as different combinations, of such materials
can be obtained in such structures than with other methods and
apparatus. The difficulty of wetting a high concentration of
fillers in attempting to pre-mix it with the resin, as well as the
difficulty in pumping and atomizing the viscous mixture, has limited
concentration of filler material to typically about 17% by volume.
This invention permits significantly higher mixed concentrations
because of the increased wetting of particulate and fibrous mater-
ials that is achieved by this new method and apparatus.
Among older methods U.S. Patent 3,399,834 shows an appa-
ratus for and a method of depositing commingled sprays of promoted
polyester and catal~st wherein a spray of the catalyst is mixed
with sprays of promoted polyester externally of the spray apparatus
usin~ a plurality -of converging sprays. Prior to deposition upon a
surface to be coated, t~e mixed spray has chopped lengths of glass
3G - 3 -
~054869
fibers mixed therewith. The chopped length of glass fibers
are used to enhance the physical properties of the polyester
resin. In addition, U.S. Patent 3,676,197 shows an apparatus
or and a method of mixing granular material entrained in a
fluid medium with sprays of a plural component material and a
curing agent and depositing the resultant mixture upon a surface
of an article.
The method and apparatus of this invention is
capable of forming multiple-component composite structures that
were not possible with prior existing methods and apparatus.
The present invention provides an apparatus for and a method
of wetting and,substantially uniformly mixing granular and fiber
material in large concentrations with a plural component
material exteriorly of a spray apparatus and prior to engagement
of such materials with and deposition,on a mold surface.
The invention in one aspect provides a method of
forming a multi,-component composite structure. This method
includeq atomizing a liquid resin material and directing same
from a plurality of spaced apart sites in such a way that the
sprays converge. The method also includes atomizing a liquid
resin curing agent and projecting the resulting spray into the
converging resin sprays from a site intermediate the sites of
atomization of the resin. Gas entrained granular material is
also projected from a site located closely adjacent one of
the sites of atomization of the resin material while a second
gas entrained granular material is directed from a site closely
adjacent the other site of atomization of the resin material
so that the two sprays of liquid and granular materials
intersect.
In a further feature of the invention, fiber
material is cut to form a plurality of cut fibers having a
1~
_ 4
f~
` 1054869
predetermined length and the cut fibers are directed into the
liquid and granular sprays from a location above the latter
thereby to prov~de a mixed spray of resin and curing agent
with entrained granular and fiber material mixed with and
wetted by the liquid resin and curing agent. This mixed spray
of resin, curing agent and granular and fiber materials is
deposited on a suitable surface.
In accordance with a further aspect of the
invention there is provided apparatus for forming multiple-
component composite structures. One form of the apparatusincludes a plurality of spray-forming means carried by a housing
at spaced apart locations. Each of the spray forming means
may be connected with a source of plural component material
including separate sources of resin and curing agent. A
granular emitting means is carried by the housing and preferably
each such means being closely adjacent a respective one of
the plurality of spray forming means. Means are provided to
entrain the granular material in a flow of gas and deliver it
to the granular emitting means. The apparatus is also provided
with a cutter to form fibrous material into fibers of pre-
determined length and means are carried by the housing to
effect operation of the plurality of spray forming means, the
granular emitting means and the cutter.
In a preferred form of the invention there is
provided a fluidized bed source of the granular material,
a hose being connected with the fluidized bed source and
terminating adjacent to the granular emitting means. The means
for entraining the granular material serve to entrain such
material in a flow of gas in the hose thereby to deliver such
granular material to the granular emitting means.
The invention, in a further aspect, provides a
~,k
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1054869
novel method of providing a mixture of liquid and solid
particulate materials. This aspect of the invention involves
atomizing the liquid material airlessly by delivering it at
high hydraulic pressure to a site of atomization and projecting
it at high velocity as a thin expanding film to-form the liquid
material into spray particles. A solid particulate material
is fluidized to form a fluidized bed and the fluidized solid
particles are entrained in a flow of compressed air. A uniform
flow of entrained solid particulate material and air is
delivered to a site of emission located closely adjacent the
site of atomization of the liquid particles. The uniform flow
of solid particles is emitted closely adjacent the high velocity
projecting liquid film so that the solid particulate material
is captured in the induced flow of air adjacent the sited
atomization of the liquid component and thoroughly mixed and
wetted therewith.
Further features and advantages of the present in-
vention will become apparent from the following description of
preferred embodiments of same taken in conjunction with the
appended claims.
FIGURE 1 is a perspective view of one embodiment of
the present invention;
FIGURE 2 is a diagrammatic view showing spray
patterns of the embodiment of FIGURE l; and
FIGURE 3 is a partial cross-sectional view of the
embodiment of FIGURE 1 through the particulate passageways in its
housing.
Referring now to FIGURE L of the drawing, a spray
apparatus of the present invention is indicated by the reference
numeral 10. The spray apparatus 10 includes housing or support
means 11, outboard plural component spray means 12 and 13 and
centrally located curing agent spray means 14 positioned between
the outboard spray means 12 and 13. The housing 11 serves as the
A t~ _
1054869
m~in suppoxt member for the outboaxd spray means 12 and 13 and for
the curing agent spray means 14. The curing agent spray means 14
may provide a spray o~ organic peroxide catalyst whexe the outboard
spray means 12 and 13 may be spraying a promoted polyester resin
or a spray of suitable amine or anhydride where the outboard spray
means are spraying an epoxy resin. Urethanes may be obtained by
the addition of a su~table isoc~anate ester to a polyester resin.
Silicone rubber may be obtained by the addition of a suitable tin
soap to a silicone elastomer.
Each of the outboard spray means 12 and 13 are suitably
connected through plural component material manifold 15 and con-
duit 16 to a source (not shown) of a plural component material.
The plural component material may be supplied under pressures of
about 300 to 3000 p.s.i. to the outboard spray means 12 and 13 by
an air-operated hydraulic pump (not shown). Using the apparatus
10 shown in FIGURE 1, the plural component material is atomized by
interaction with the surrounding air upon emerging from the ori-
fices of the outboard spray means 12 and 13. The plural component
material, of course, may be atomized by any other suitable means
such as by compressed air. The outboard spray means 12 and 13 are
illustrated as including nozzles which hydraulically atomize the
plural component material, and the curing agent spray means 14 is
illustrated as being a compressed air spray means. The outboard
spra~ means 12 and 13 are angled or inclined toward each other as
shown in FIGURE 2 in such a manner that the spray patterns 19 and
20 pro~ided by each of the outboard spray means converge and
intersect at a Iocus spaced a~out five inches from the front of
the spray apparatus 10,
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~054869
The centrally Iocated curing agent spra~ means 14 is
flanked by and on substant~all~ the same horizontal plane with
the outboard spra~ means 12 and 13~ The curing agent spra~ means
14 is connected to a source ~n~t shown~ of curing agent through
curing agent man~fold 17 and conduit 18. The curing agent spray
means 14 is positioned to provide a spray 21 of curing agent that
intersects the con~erging sprays o~ the outboard means at the locus
of their intersection. The vertical width o~ the spray pattern of
the curing agent as it intersects the sprays of the outboard spray
means 12 and 13 is preferably substantially the same as the ver-
tical width of the sprays of the plural component material to
assure substantially uniform mixing of the curing agent with the
plural component material.
In order to provide a spray of substantially uniformly
mixed plural component material and curing agent, the curing agent
spray means 14 is desirably centrally located between the outboard
spray means 12 and 13. The outboard spray means 12 and 13, when
dispensing a polyester resin, dispense up to about 99 weight per-
cent of the total weight of the fluid component of the spray
issuing from apparatus 10. The outboard spray means 12 and 13 dis-
pense approximately 50 weight percent of the total weight of the
fluid component when dispensing a urethane. The remainder of the
liquid component of the spray issuing from the spray means 10 is
dispensed by the curing agent spray means 14. The relative ratios
of other resins and cur~ng agents, of course, may vary, depending
upon the plural component material used, Locations of the curing
agent spray means 14 at a posit~on other than centrally between the
outboard spray means 12 and 13 may not yield as thorough a mixing
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lOS4869
of the. cuxing agent wi.th the othex p.lural component.and may result
in an undesixable'defl:ect~on in the resulting spra~
Spaced fxom but positioned closel~ ad~'acent each of the
outboard spxay means are gxanula~ material emitting means 22 and
23. The'granular emittin~ means ma~ include spray-forming no:zzles
pivotally mounted upon housing 11 to direct the granular material
emitted toward the sprays from the outboard spray means 12 and 13
as desired.
The'granular material may be any suitable material which,
by using a suitable fluidized bed and immexsed venturi pump, may
be entrained in a flowing stream of compressed air, or may be con-
veyed using any other suitable granular material conveying means.
Such granular material may include perlite, clay, sand, talc, mica,
aluminum hydrate, calcium carbonate, calcium silicate, glass beads,
plastic spheres, fire retardants and the like.
A suitable source of granular material is shown in
FIGURE 1. The source includes an open container 24 with a
porous plate 25 ad;acent its bottom to form an air chamber
26 at its bottom. The granular material is supported by the
porous plate 25, which is made from a material like sintered
polyethylene. Compressed air from an air source is supplied .
through hose 27 to an immersed venturi pump 28 and through a
sealed tube 29 to the air chamber 26. The slow and uniform
flow of air through porous plate 25 fluidizes the granular
material in the container 24, and the flow of compressed air
thxough the. venturi pump 2~ dxaws. the fluidized ~ranular material
into an openin~ (not shown] in the. ven.turi pump, entrains it in
the mo~ing air stream and deIi~ers it through hose 30 to a smooth
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1054869
passageway or passageways in housing 11 (sho~n more'particularly
in FIGURE 3~ that dixect the'air-entrained granular material to
granular spray-,forming nozzles 22 and 23 that are mounted on and
carried by housing 11.
FIGURE 3 shows in gXeater detail the portion of appa~
ratus 10 that is associated with'the emission o~ granular filler
materials, The'passageways lla ~only one of which is shown in
FIGURE 3) in housing 11 through which granular and particulate
material are directed are straight throughout the housing. The
granular spray~forming nozzles 22 and 23 are mounted at the
forward end of passageways lla. The hose 30 conveying the granular
material from the fluidized bed is inserted into and held within
the passageways lla by a hose retainer 30a. Hose 30 extends thus
from the source of powder 24 up to the granular nozzle means 22
and 23 and provides an uninterrupted and smooth-walled passageway
for the air-entrained granular material to provide an even delivery
of granular particles to the spray-forming means.
The granular nozzles may be designed to form the air-
entrained granular material into any pattern desired for association
with the liquid plural component material sprays from nozzles 12,
13 and 14. The outputs of the granular nozzles 22 and 23 are
located closely adjacent to the outboard spray means 12 and 13.
The creation of spray by these liquid spray means forms an area of
lo~ pressure closel~ adjacent the means 12 and 13. Locating the
granular~emitting nozzles closely ad;acent this area of low pres-
sure, as for example~ within an inch or so, results in entrapment
of the 'granular material in the liquid spray with the assistance
of the 'air ~low adj'acent the front of the apparatus 10. The
~ 8 ~
1054~369
nozzles 22 and 23 shown in FIGURE 1 and FIGURE 2, for example,
include orifices that are generally elliptical with'a ma~or dia
meter o~ about 0.5 inches and a m~nor diameter of about 0.25
inches. The nozzles include inner surfaces adjacent to orifices
that are 'cun7ed to direct the air~entrained granular material into
the area adjacent thé means forming the liquid spra~s.
The granular material from nozzles 22 and 23 should in~
tersect the sprays of the pluraI component material so that the
granular material is adequately wetted by and substantially uni-
10 formly mixed with the plural component material prior to depositionupon surface 31. ~ocating the granular~-emitting means 22 and 23
about one inch above the 'orifices of the outboard spray means 12
and 13 and curing agent spray means 14 so the granular material is
brought into the spray of plural component material within several
inches of the front of the spray apparatus 10 appears to result in
good wetting and substantially uniform mixing of the granular
material with the sprays of the liquid plural component material.
A cutter means 32 is used to spray and deposit cut fibers
with the plural component material and granular material. The cut-
20 ter means 32 cuts fibers into various lengths by changing the spacingbetween blades in a cutting wheel within the cutter. Such a cutter
means 32, described in U.S. Patent 3,399,834, preferably includes a
housing 33, an adjustable attaching means 34, and a directional
opening 35.
In this type of cutter means, the attaching means 34
provides for m~3vable mounting of the housiny 33 upon the housing 11,
pre~erablx~ ahove 'the granular emitting means and so that the open-
ing 35 through which the 'cut roving is ej'ected may be angularly
_ 9 _
1054869
Yaried with xespect to the spray~ issuing from spray means 12, 13,
14, 22 and 23. Th~s pro~des for directlng the cut roving in the
spray streams so that the roving ~ill be "pre~et" and will not
ride on top of ox fall through the spray stream.
Cutter means 32 is positioned to receive roving strand
36 and to cut the continuous strands into short filaments, which
are then e;ected through opening 35 into the spray streams of
spray means 12, 13, 14, 22 and 23, as shown in FIGURE 2. Fiber
material most frequently used is a roving of glass fibers. The
¢ut lengths of fiber glass can be~ used to provide reinforcement
throughout the body of the composite material.
Operation of the apparatus can be effected by actuation
of trigger means 38 carried by housing 11. Actuation of trigger
means 38 can provide in the proper sequence, operation of valve
m~ans controlling the flow of liquid to spray means 12, 13 and
14, the flow of atomizing air to spray means 14, and the flow
of compressed air to air motor 37. The flow of compressed air
to the apparatus 10 through hose 39 can be detected by an air
flow switch (not shown) whose output can be used to effect a flow
of air to the granular material source through hose 27 and de-
liYery of granular material to apparatus 10 through hose 30.
Release of the trigger 38 will substantially simultane-
ously terminate the flow of plural component material from spray
means 12 and 13, the flow o~ curing agent and atomizing air from
spray means 14 of apparatus 10 and the flow of granular material
and fibers from granular emitting means 22 and 23 and cutter
means 32.
As shown in FIGURE 2a, the con~erging spray streams 19
~ 10 ``
1054869
and 20 issuing from outboaxd spxa~ means 12 and l3 may have a sub-
stantially oval ox ~elliptical~shaped trans~erse cross s~ection.
The liquid spra~s are formed bel~w the means to emit granular
material and films and form a base for ~such materials. As shown
in FIGURE 2b, emission of the particulate material closely adja-
cent thé sites of formation of the liquid sprays results in the
granular material being quic~ly urged into the liquid sprays. The
intersection of the converging liquid and granular sprays issuing
from the outboard liquid and granular spray means and the fibers
from cutter means 32, as shown in FIGURE 2c, causes a resultant
mixed homogeneous spray with the granular and fiber material
substantially uniformly wetted by the liquid and distributed in
the spray.
As illustrated in FIGURE 2a, the array of liquid and
solid sprays form a pyramid-like arrangement before intersecting.
The outboard liquid sprays 19 and 20 carry almost all the liquid
material sprayed and form a spray pattern base with the curing
agent spray 21. They capture the granular materials emitted from
nozzles 22 and 23 and the fibers ejected from orifice 35 and inter-
secting, uniformly mix and wet the granular materials and fibers.Where cut fibers are used, they form a significant percentage of
the weight of the composite spray material, typically 25 to 35 per-
cent in glass~reinforced polyester structures; however, lower
percentages may be used, if desirable.
Where two different granular materials are used, such
as ~lass beads and aluminum hydrate~ the apparatus lO can be ar-
ranged to intermingle the two paxticulate materials prior to, or
at about the locus of intersection with the liquid sprays.
~ 11 -
1054869
The apparatus of this invention thus ~orms a superior
means to mix a plurality of materials. The liquid components are
at~mized by the use of a high h~dxaulic pressure'of from 300 to
300~ p s.i. and with specially shaped nozzles', for example~
adapted to form the li~uid into a thin, expanding fan~shaped form.
The liquid is e~'ected at a very high'velocit~ from the nozzles
and atomized by interaction with'the atmosphere. An area of low
pressure is created ad~acent the nozzles b~ operation of the noz~
zles in forming the spray. Particulate, or granular, material to
be mixed with the liquid component is uni~ormly delivered to and
released closely adjacent the liquid nozzles in the low pressure
area where it is captured by the air flow at the front of the appa-
ratus. With two liquid nozzles in use, two particulate components
may be used, one located closely adjacent each liquid nozzle so
that each particulate material is captured by a spray of liquid
material. By directing the two liquid nozzles so that they inter-
sect, the liquid and granular spra~s are uniformly mixed and the
particulate material is wetted. Plural component material may be
formed with an unusually high percentage of particulate material
using this method and apparatus. In addition, fibers can be added
to this material by cutting and ejecting the fibers into the air ``
flow forwardly of the apparatus. Where a catalyzed resin liquid
~ jnt1~oJ.u c ed
~ I material is used, curing agent is desirably lntroducted- into the
L J~i
spray from between the two liquid nozzles.
Suitable additives may be introduced into the plural
component material for color, ultraviolet absorption, flame-
proofing and the like.' Pi~ments ma~ be used to achieve'the desired
color of the plural component material. Antimony oxide, aluminum
~ 12 -
1054869
trih~.drate.~. chlorinated ~axes. and the like may. be. us.ed to assist in
flame~proofing the:plural component material.
The. ~olume of granular material to plural component
material may. vary considerabl~, Using perlite, the volume of
perlite ma~ be'about 30 to 65 percent b~. volume of perlite with the
remaining percentage of polyester resin. Using glass beads, the
percentage of total volume'that may be glass beads is most gener-
ally 20 to 40 percent; howe~er, smaller percentages may be used,
if desirable.
The thickness of a coating of plural component material
and granular material. using this method and apparatus may be as
desired. The lower limit on thickness of the coating is about 15
to 20 mils with the upper limit only limited by the economics of
the situation. Generally, for coatings having good weathering char-
acteristics and strength, the thickness of a coating including a
binder of polyester and perlite granular material should approach
about 0.125 to about 0.25 of an inch or more.
Cut fiber glass provides reinforcement and may be used
in percentages of 10 to 30 percent, to be determined by the diffi-
culty of roll-out. Thick coatings of material, including cut fiber
glass and particulate, must be "rolled out"; that is, the deposited
coating must be worked with a roller to eliminate air trapped in
the interstices of the fibers. Where these composite coatings are
too thick, it is not possible to roll out such entrapped air. The
coating is instead pushed about by the roller and entrapped air is
not xemoved. Thus such mixed coatings on the order of one inch
thick are'not practical ~ith :cut glass fibers.
The spxay apparatus 10 may be hand held or carried by any
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1054869
suitable b~om (not sho~n~ and mo~ahle base (not shown) to facili-
ta1:e thé movement of the spra~ appara*us.
The following examples axe intended to illustrate the
formation of multiple component composite structures using the
apparatus and method of this invention~
EXAMPLE I
A laminated multicomponent structure can be manufactured
using the method and apparatus of this invention by the follow~
ing prGceaures. A mold surface is spaced about l8~36 inches in
front of the spray apparatus lO. Polyester resin is supplied to
the outboard spray means at a pressure of about 2000 p.s.i. at a
rate of about l900 cubic centimeters per minute through the airless
spray nozzles forming the polyester resin into an elongated, fan-
shaped spray pattern having an acute angle of 25 degrees. The
sprays from the outboard spray means converge about 5 inches in
front of the spray apparatus. Undiluted methyl ethyl ketone per-
oxide catalyst is atomized from the central nozzle at a rate of
about 30 cubic centimeters per minute, using atomizing air pressure
of 20 p.s.i. from a compressed air spray nozzle of more or less
standard confi~uration, such as the Spraying Systems' No. El8B. A
spray of catalyst intersects the outboard spray means about 5 inches
in front of the spray apparatus at the locus of their intersection.
Aluminum trihydrate, the granular material, is supplied to the gran-
ular emitting nozzles associated with the outboard spray means at a
rate of about 2050 grams per minute. The granular emitting spray
means are Iocated closel~ adjacent the sites of atomization of the
polyester resin to direct the aluminum trihydrate into the liquid
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1054869
spray. The aluminum trihydrate is manufactured by Aluminum Company
~A of America and sold under the trade ~m ~ALCOA C3II'. Chopped
fiber glass is directed into the spray of liquid and granular
mat:erial at a rate of about 1.5 pounds per minute. The cut fibers
have an average length o~ about one inch. This composite laminate
is deposited on the mold surface to a thickness of about .1 of an
inch. Entrapped air is rolled out of this coating. This layer is
allowed to cure at room temperature of 70 degrees Fahrenheit for
one hour.
A central core is then deposited upon the resulting
laminate structure. As before, the apparatus is spaced 18~36
inches away from the laminate. Polyester resin is supplied to the
outboard spray means under a pressure of 2000 p.s.i. at the pump at
a rate of about 1900 cubic centimeters per minute. The outboard
spray means are nozzles which form the polyester resin material into
aan elongated spray pattern having an acute angle of about 25 degrees.
As before, the outboard sprays converge about five inches in front
of the spray apparatus. Undiluted methyl ethyl ketone peroxide
catalyst is delivered to a compressed air atomizing nozzle at a
rate of about 40 cubic centimeters per minute and atomized by com-
pressed air supplied to the atomizing nozzle at 20 p.s.i. A spray
of peroxide catalyst intersects the resin sprays about 5 inches in
front of the spray apparatus. From the central core, the aluminum
trihydrate is supplied to only one of the granular emitting means
- at a rate of about 400 grams per minute. The other spray emitting
means is connected wit~ the source of Minnesota Mining and Manufac-
turing Company glass beads. These glass beads have an average dia-
meter of about three mils. Thé Minnesota Mining and Manufacturing
~ 15 -
105~869
Compan~ glass beads are su~plied to the other ~ranular emitting
means at a rate of abDut 8QQ ~rams per minute. Thè two granular
emitting means are 'Ioc~ted closel~ adjacent the 'resin atomiz-ers and
direct the''glass bubbles and alumin'um, trihydrate 'into the liquid
sprays in front of the appa~atus. The commingled~ catalyzed poly-
ester resin, the 'glass beads and aluminum trihydrate are carried
and deposited on the first layer to a thickness of about .1 of an
inch. The central core is then allowed to cure at ambient tempera-
ture of 70 degrees Fahrenheit for about 60 minutes.
After the central core has had an opportunity to cure,
a top layer like the bottom layer is added to the central core.
The apparatus and method of operation are exactly like those used
in making the first layer and the materials in this top layer are
deposited to a thickness of .1 of an inch and rolled out as before.
The top layer is then allowed to cure for about 60 minutes at 70
degrees Fahrenheit.
The resulting three-layered laminate is a rigid, composite
structure of .3 of an inch thick, having glass reinforced outer
layers and a low density central layer to increase its rigidity.
Because of the use of the aluminum trihydrate and the glass beads,
approximately 25 percent less resin is used to form this structure
than would otherwise have been required with a resulting saving in
weight and cost.
EXAMPLE II
A composite structure is manufactured using the apparatus
and method of this invention with the benefits of a substantial
sa~ing in res'in and weight and ~ith little, if any loss of rigidity
- 16 -
1054869
and strength. The surface of a mQld is spaced a~Qut 18 to 36 inches
in front of the'spra~ apparatus 10. Pol~ester resin is supplied to
the outboard spra~ means under a pressure of 2000 p.s.i. at the pump
at the rate of about 1900 cubic centimeters per minute through air-
less nozzles' forming the pol~es'tex res'in into an elongated fan-like
spray pattern having an acute angle o~ about 25 degrees. Undiluted
methyl ethyl ket'one'peroxide'is supplled to the atomizing nozzle
at a rate'of 40 cubic centimeters per minute and atomized by com~
pressed air supplied to the Spraying System No. E18B atomizing
nozzle at 20 p.s.i. The liquid sprays of resin and catalyst inter-
sect about 5 inches forwardly of the apparatus. Particulate
aluminum trihydrate, sold by Aluminum Company of America under the
trade name i'ALC~A C31", is supplied to the two granular emitting
means at a combined rate o~ 2000 grams per minute. The granular
emitting means are arranged to direct the aluminum trihydrate into
the liquid sprays forwardly of the site of formation of the liquid
sprays. Fiber glass roving is cut and expelled into the liquid and
granular sprays at a rate of 400 grams per minute. Standard fiber
glass gun roving is cut into fibers having an average length of
about 3/4 of an inch. The composite material is sprayed onto the
mold form to a thickness of about .1 of an inch and is allowed to
cure at room temperature of 70 degrees Fahxenheit. The resulting
composite material structure was a rigid, translucent, glass-
reinforced polyester sheet having low density and good strength.
~;,,, ~rk
~A "Suzorite", a particulate mica sold under this ~ by Marietta
Resources International Ltd., can be substituted for the aluminum
trihydrate.'
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1~5~869
`EXAMPL'~'I`II
A composite material structure was prepared that is
suitable'for thé hull of a boat. Pure pigmented catalyst poly-
ester resin is spxa~ed onto a polished mold surface to a thickness
of about .005 inches. The' piymented polyes'ter resin is a high
quality type of the'type normally used as gel coat in the manufac-
ture of polyes'ter resin particles and in spra~ing, the apparatus
is operated in a manner known to those 'skilled in the art. Then
glass beads are added to the gel coat and anothe'r .010 inches of
coating is applied. The geI coat resin is allowed to cure for 60
minutes at 70 degrees Fahrenheit. When the gel coat has cured,
the procedure as set forth in Example I above was repeated, but
with glass bubbles substituted for ALCOA C31 in the central core.
The resulting composite material structure was ideally suited for
the hull of a boat.
The method and apparatus of this invention can thus be
used to manufacture many different composite material structures.
Such a device is particularly applicablé in the manufacture of
boats, bathroom fixtures, counter tops, and many other such
20'' 'items.
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