Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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REUSABLE CONCRETE FORM PANEL SHEETING
FIELD OF THE INVENTION
This invention relates to a new structural
member that is a useful substitute for plywood and
other structural materials, e.g., for general
construction purposes. The new structural member
has particular utility as a component in concrete
forms that are erected for pouring a concrete
member, such as a wall, floor, ceiling, deck, or the
like, which forms are subsequently removed from the
concrete member after the concrete has cured.
BACKGROUND OF THE INVENTION
Removable, modular concrete forms
typically comprise a rectangular plywood panel
sheet, e.g., high-density overlay (HDO) Douglas Fir
plywood, supported by, e.g., a steel or wooden frame
on the backside face and, in some embodiments, on
the circumference of the panel sheet. To create a
concrete structure such as a wall, the concrete
forms are temporarily assembled in a spaced,
parallel relationship with inwardly-facing panel
sheets, and fresh (liquid) concrete is poured in the
cavity or hollow defined by the forms. The
thickness of the concrete wall is established by the
spacing between panel sheets, which spacing
typically is maintained by wall ties. The height
and length of the concrete wall is adjusted by
adjacently interconnecting a plurality of forms to
vary the height or length of the hollow. After the
concrete has "set" or "cured," the forms are
I I
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stripped away from the wall, and can be reused to create
additional concrete members.
In addition to prefabricated modular concrete
forms having a panel sheeting and attached frame, job-
built concrete form networks and frameworks are used in
the industry to construct concrete members, e.g.,
concrete bridges and dams. To construct a typical job-
built concrete form network or framework, plywood panel
sheeting, typically having no prefabricated frame, is
interconnected and supported with, e.g., a lumber frame
that is custom-built on-sight, to meet the particular
engineering specifications of the job.
Plywood possesses a useful combination of
physical properties (e.g., strength, durability,
flexibility, nail retention) that make it an industry
standard for use as concrete form panel sheeting.
Nonetheless, plywood concrete form panel sheeting has
many undesirable features and disadvantages. First,
plywood is an increasingly expensive construction
material made from trees, which constitute a natural
resource of increasing scarcity that has been the subject
of increased environmental protection in recent years. A
need exists for concrete form panel sheeting made of
alternative, and preferably less costly, construction
materials.
Second, the excessive weight of plywood
concrete form panel sheeting is burdensome. Standard
building foundation concrete forms may be 0.61 meters x
2.44 meters (0.61 m x 2.44 m) [2 feet x 8 feet (2' x 8')]
in size and have plywood panel sheeting that is 1.27 to
3.81 centimeters (cm) [1/2 to 1 1/2 inches (1/2" - 1
1/211)] thick. A complete 0.61 m x 2.44 m(2' x 8')
concrete form, with a steel frame attached to the plywood
panel sheeting, typically weighs from 34-38.6 kilograms
(kg) [75 to 85 pounds].
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The weight of such forms makes the forms awkward and
difficult for construction workers to maneuver and
increases the cost of shipping such forms to and from a
construction site. Therefore, a need exists for lighter
concrete form panel sheeting, to use in construction of
lighter concrete forms. At the same time, concrete forms
typically are roughly treated (e.g., during assembly for
pouring a concrete structure; stripping and disassembly;
and stacking for storage and transportation). A need
exists for lighter concrete forms that nonetheless are
physically durable and abrasion resistant.
Conventional plywood concrete form panel
sheeting requires the use of an external form release
agent (e.g., form oil) which results in a further set of
problems and disadvantages. More particularly, prior to
pouring a concrete wall or other member, the concrete-
form face (i.e., the concrete-facing face) of the plywood
panel sheeting of a concrete form is oiled to prevent the
plywood from adhering strongly to the concrete. Failure
to oil the plywood forms results in splintering of the
plywood when it is pulled from the concrete, drastically
shortening the life of the concrete form. The oiling
step consumes time and form oil. Thus, economic reasons
create a need for oil-free concrete forms.
The oiling of concrete forms has undesirable
environmental impacts, too. For example, a certain
amount of the form oil that is used, e.g., when pouring a
concrete building foundation, inevitably ends up on the
ground. More significantly, the plywood in a concrete
form panel absorbs oil during each use; a conventional
0.61 m x 2.44 m(2' x 8') panel can be expected to absorb
about three pounds
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of oil during its useful life of 5-200 concrete pours.
The absorbed oil softens the panel sheeting, which leads
to unacceptable flexing and cracking. The oil-soaked
plywood is worthless; safe disposal of this waste
material is an environmental and economic concern of
significant proportion, when one considers that at least
about 46.5 million square meters (500 million square
feet) of plywood concrete forms are produced annually. A
long-felt need exists for reusable concrete forms which
absorb less form oil, and for forms and methods for
creating concrete members which permit reduced use of
external form release agents, or which permit elimination
of external form release agents entirely.
A long-felt need also exists for concrete form
par--l sheeting that will last longer than existing
plywood sheeting and that can be recycled after its
useful life. After about 5-200 concrete pours, plywood
sheeting softens due to absorption of form oil, water,
and chemicals from the liquid concrete. This absorption
problem is acute at holes in the plywood, such as nail or
rivet holes where the plywood sheeting has been attached
to, e.g., a concrete form frame, block-outs, windows, or
the like. The absorption problem often will result in
the separation of laminates within the plywood or
attached to the concrete-form face of the plywood. A
need exists for concrete form panel sheeting that is
resistant to such absorption and degradation.
Plastic-coated plywood has been used
successfully as concrete form panel sheeting, and some
such materials will release more easily from cured
concrete than HDO plywood. However, these materials
typically are heavier than HDO plywood panel sheeting,
and their useful life is limited due
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to the inability to create a durable bond between
the plastic and plywood laminates. Concrete lime
destroys this bond and results in delamination,
particularly at nail holes and impact holes in a
5 panel. A need exists for concrete form panel
sheeting that is resistant to such delamination.
U.S. Patent No. 4,463,926, issued August
7, 1984, describes a form of assembled elements
which include a molding face of polyurethane
elastomer; a plastic rear face having grooves, in
which is incorporated a glass cloth; an envelope
filler of rigid polyurethane foam; edges having a
reinforced lip and attachment points for assembly
means; a reinforcing framework of metallic profile
members located at the junctions between pairs of
panels; and a support scaffold of triangular trellis
construction conforming at the rear of the form to
the profiles of the reinforcing framework. See also
European Patent Publication No. 0 077 579 Al,
published 27 April 1983.
German Utility Model Registration No. G 94
15 570.4 U1, published 9 March 1995, describes a
three-layer formwork made of plastic, comprising a
core of foamed polystyrene with amounts of aluminum
foil regenerated from packaging waste; and two
covering layers consisting of phenol-formaldehyde-
resin-impregnated mats made of alkali-free glass
fibers.
Canadian patent application 2,055,371,
published May 15, 1992, describes a construction
element having a foamed plastic inner region; two
outer shell regions; mats of metal filaments, metal
bars derived from metal sheet, or ribbed expanded
metal embedded within the outer shell regions. See
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also European Patent Publication 0 487 952 Al,
published 3 June 1992.
European Patent Publication No. 0 353 637,
published 7 February 1990, describes a formwork
board for pouring concrete consisting of PVC
granulate and foamable plastic binder, i.e.,
polyurethane. The formwork board preferably has a
protective coating of polyurethane, wood veneer, or
a glass or plastic mat. Reinforcements for the
formwork board are described consisting of glass,
plastic, or metal fabric on the front and back sides
of the formwork board; hollow metal profiles
insertable into cavities in the formwork board;
metal grids mounted on the backside of the formwork
board; or flat iron strips parallel to edges of the
formwork board.
United States Patent No. 3,592,435, issued
July 13, 1971, describes a form structure having a
vinyl foam core; fiberglass matts external to the
foam core; polyester resin material to bind the
fiberglass matts to adjacent layers and to provide a
smooth, hard outer surface; spaced upright end joint
members secured to opposite upright ends of the main
body core material, and upper and lower edge members
secured to upper and lower edges of the main body
core.
SUMMARY OF THE INVENTION
Broadly, the present invention is directed
to a structural member that is a useful substitute
for plywood and other structural materials wherever
such materials are employed, e.g., for constructing
walls, floors, roofs, ceilings, and the like. In
preferred embodiments, the structural member is
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recyclable without time-consuming and expensive
separation of incompatible materials.
More particularly, the invention is
directed to concrete form panel sheeting formed from
a polymer resin. For example, the invention is
directed to a concrete form panel sheeting
comprising a resinous polymer core defining a
concrete-form face and an opposite (backside) face,
and a concrete-facing surface layer (or "face
sheet") attached to the concrete-form face of the
core. The concrete-facing surface layer is adapted
to be contacted by fresh concrete and to release
from the concrete after curing thereof, to
facilitate reuse of the concrete form panel
sheeting. Similarly, the invention is directed to a
concrete form panel sheeting comprising a resinous
polymer foam core defining a concrete-form face and
an opposite face, and a concrete-facing surface
layer attached to the concrete-form face of the
core, the concrete-facing surface layer comprising a
thermoplastic resin. In preferred embodiments, the
concrete form panel sheeting further comprises a
backside surface layer attached to the opposite face
of the core, the backside surface layer imparting
resistance to deflection to the concrete form panel
sheeting. Also in preferred embodiments, the
concrete form panel sheeting further comprises a
stiffening means for imparting resistance to
deflection to the concrete form panel sheeting, the
stiffening means being integral with the resinous
polymer core. To impart more resistance to
deflection, the concrete form panel sheeting
includes both a stiffening means and a backside
surface layer.
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Thus, in one embodiment, the invention provides a
concrete form panel sheeting comprising: a resinous polymer
core defining a concrete-form face and an opposite face, the
concrete-form face and the opposite face defining edges of
the concrete form panel sheeting; and a concrete-facing
surface layer attached to the concrete-form face of the
core; the concrete form panel sheeting characterized by: a
stiffener integral with the resinous polymer core, the
stiffener being oriented substantially parallel to the
concrete form face and the opposite face, and substantially
transverse to said edges. In a preferred embodiment, the
concrete form panel sheeting additionally comprises a
backside surface layer attached to the opposite face of the
core.
The concrete form panel sheeting of the present
invention preferably answers one or more of the art-
recognized needs discussed above. For example, the panel
sheeting is less expensive to construct and/or less
expensive over the useable life of the sheeting; is lighter;
is more durable; is releasable from concrete with limited
application or without application of an external form
release agent; is longer-lasting; and/or is recyclable.
In a related aspect, the invention is directed to
a removable concrete form comprising (1) a concrete form
panel sheeting of the present invention, and (2) a concrete
form frame attached to the concrete form panel sheeting.
Such concrete forms preferably answer one or more of the
art-recognized needs discussed above.
In another aspect, the invention relates to a
concrete form network comprising a plurality of connected
concrete form panel sheetings, wherein at least one of said
concrete form panel sheetings is a concrete form panel
sheeting of the present invention; and further comprising a
support structure fcr maintaining the panel sheetings in a
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substantially fixed position when said panel
sheetings are contacted by fresh concrete.
In another aspect, the invention is
directed to methods for creating a concrete member.
For example, the invention includes a method of
creating a concrete member comprising the steps of:
(a) defining a cavity for pouring fresh concrete,
the cavity defined by at least one concrete form
panel sheeting of the invention, the concrete form
panel sheeting comprising, e.g., a resinous polymer
core defining a concrete-form face and an opposite
face, and a concrete-facing surface layer attached
to the concrete-form face of the core, the concrete-
facing surface layer being adapted to be contacted
by fresh concrete and to release from the concrete
after curing thereof, to facilitate reuse of the
concrete form panel sheeting; (b) pouring concrete
into the cavity; (c) curing the concrete to form a
concrete member; and (d) separating the concrete
member and the concrete form panel sheeting.
Similarly, the invention includes a method
for creating a concrete member comprising: (a)
interconnecting a plurality of concrete form panel
sheetings to define a hollow, wherein at least one
of the concrete form panel sheetings comprises a
resinous polymer core defining a concrete-form face
and an opposite face, and a concrete-facing surface
layer attached to the concrete-form face of the
core, the concrete-facing surface layer comprising a
thermoplastic resin; (b) pouring concrete into the
hollow; (c) curing the concrete to form a concrete
member; and (d) separating the concrete member and
the concrete form panel sheetings.
A related aspect of the invention is a
method of creating a concrete member (e.g., a wall,
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a deck, or other structure) using the removable
concrete forms of the present invention. More
particularly, the invention is directed to a method
of creating a concrete member using the novel
removable concrete forms described herein,
comprising the steps of: (a) interconnecting a
plurality of the concrete forms, the concrete-facing
surface layers of the concrete forms defining a
cavity; (b) pouring concrete into the cavity; (c)
curing the concrete to form a concrete member; and
(d) removing the concrete forms from the concrete
member.
Similarly, the invention is directed to a
method of creating a horizontally disposed concrete
member using the novel concrete form panel sheeting
described herein, comprising the steps of: (a)
interconnecting a plurality of the concrete form
panel sheetings, the concrete-facing surface layers
thereof defining a shoring surface; (b) pouring
concrete onto the shoring surface; (c) curing the
concrete to form a horizontally disposed concrete
member; and (d) removing the concrete forms from the
concrete member.
These and other aspects of the invention
will be apparent from the following detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective, partially
elevated, partially cut away view of concrete form
panel sheeting having a core and a concrete-facing
surface layer adhered to the core with an adhesive.
Fig. 2A is a partially-elevated
perspective view, partially cut away, of concrete
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form panel sheeting having a core, a concrete-facing
surface layer, and a backside surface layer.
Figs. 2B and 2C are partially-elevated
perspective views, partially cut away, of two
embodiments of concrete form panel sheeting having a
core, a stiffener integral with the core, a
concrete-facing surface layer, and a backside
surface layer.
Figs. 2D-2G are partially-elevated
perspective views of corrugated stiffener members
having wavy, rectangular, triangular, and
trapezoidal cross-sectional geometries,
respectively.
Fig. 3 is a partially-elevated, partially
cut away perspective view of a rectangular concrete
form having concrete form panel sheeting and a
f rame .
Fig. 4 is a cross-sectional view of a
portion of a concrete form, depicting.the attachment
of a frame to concrete form panel sheeting.
Fig. 5 is a view of a the corner of a
concrete form.
Fig. 6 is a cross-sectional view of a
portion of a concrete form, depicting an alternative
attachment of a frame to concrete form panel
sheeting.
Fig. 7 is a partially-elevated perspective
view, partially cut away, of a concrete form
network.
Fig. 8 is a perspective view of a portion
of a concrete form network, depicting the connection
of two adjacent concrete forms and a spacer.
Figs. 9 and 10 are partially-elevated
perspective views of rectangular concrete forms each
having concrete form panel sheeting and a frame.
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Fig. 11 is a perspective view of a portion
of a concrete form network, partially cut away,
depicting the connection of two adjacent concrete
forms and a spacer.
Figs. 12 and 13 are partially-elevated
perspective views, partially cut away, of concrete
form networks.
Fig. 14 is a perspective view, partially
cut away, of a shoring concrete form network.
Fig. 15A depicts tensile strength (ASTM-
D1623) in pounds per square inch (psi) for varying
densities, in pounds per cubic foot (pcf), of GECET
F100 resins.
Fig. 15B depicts flexural strength (ASTM-
C203) for varying densities of GECETO F100 resins.
Fig. 15C depicts flexural modulus for
varying densities of GECET* F100 resins.
Fig. 15D depicts compressive strength
(ASTM-D1621) for varying densities of GECETO F100
resins at varying strains.
Fig. 15E depicts energy impact (in foot-
pounds) at room temperature using 0.375 inch samples
made from GECET F100 resins of varying densities.
Fig. 15F depicts energy impact (in foot-
pounds) after 96 hours at 248'F using 0.375 inch
samples made from GECET" F100 resins of varying
densities.
Figs. 15G - 15I depict the fastener
retention properties of GECETO F100 resins. Force
(in pounds) required to remove dry wall screws (Fig
15G), finishing nails (Fig. 15H), and galvanized
roof nails (151) from GECETO F100 resin at different
densities is depicted.
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Fig. 16A depicts tensile strength (ASTM-
D1623) for varying densities of GECET' F200 resins.
Fig. 16B depicts flexural strength (ASTM-
C203) for varying densities of GECET" F200 resins.
Fig. 16C depicts flexural modulus for
varying densities of GECETO F200 resins.
Fig. 16D depicts compressive strength
(ASTM-D1621) for varying densities of GECET F200
resins at varying strains.
Fig. 16E depicts energy impact (in foot-
pounds) at room temperature using 0.375 inch samples
made from GECETO F200 resins of varying densities.
Fig. 16F depicts energy impact (in foot-
pounds) after 96 hours at 248F using 0.375 inch
samples made from GECETO F200 resins of varying
densities.
Figs. 16G - 161 depict the fastener
retention properties of GECET' F200 resins. Force
(in pounds) required to remove dry wall screws (Fig
16G), finishing nails (Fig. 16H), and galvanized
roof nails (161) from GECETO F200 resin at different
densities is depicted.
Fig. 17A depicts tensile strength (ASTM-
D1623) for varying densities of GECETO F300 resins.
Fig. 17B depicts tensile strength at break
in psi for varying densities of GECET' F300 resins.
Fig. 17C depicts flexural strength (ASTM-
C203) for varying densities of GECETO F300 resins.
Fig. 17D depicts flexural modulus for
varying densities of GECET F300 resins.
Fig. 17E depicts compressive strength
(ASTM-D1621) for varying densities of GECETO F300
resins at varying strains.
RECTIFIED SHEET (RULE 91)
ISA/EP
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Fig. 17F depicts energy impact (in foot-
pounds) at room temperature using 0.375 inch samples
made from GECETO F300 resins of varying densities.
Fig. 17G depicts energy impact (in foot-
pounds) after 96 hours at 248F using 0.375 inch
samples made from GECETO F300 resins of varying
densities.
Figs. 17H - 17J depict the fastener
retention properties of GECET* F300 resins. Force
(in pounds) required to remove dry wall screws (Fig
17H), finishing nails (Fig. 171), and galvanized
roof nails (17J) from GECETO F300 resin at different
densities is depicted.
DETAILED DESCRIPTION OF THE INVENTION
In a basic embodiment depicted in Fig. 1,
the concrete form panel sheeting of the present
invention comprises (A) a resinous polymer core 2
defining a concrete-form face 4 and an opposite face
6, the core member being attached to (B) a concrete-
facing surface layer (or "face sheet") 8 adapted to
be contacted by uncured concrete and to release from
the concrete after curing thereof. As explained
more fully below, the core member may be attached to
the concrete-facing surface layer by means of an
adhesive layer 10, or by other suitable connection
means. The core member itself may be constructed
from multiple, attached layers of material.
In another embodiment, depicted in Fig.
2A, the opposite face of the resinous polymer core 2
is adhered to (C) a backside surface layer (or "back
sheet") 12, which may be of the same or different
material as the concrete-facing surface layer 8, and
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which also is attached to the core by an adhesive or
other attachment means.
In embodiments depicted in Figs. 2B and
2C, the concrete form panel sheeting has a resinous
polymer core 2 attached to a concrete-facing surface
layer 8 and a backside surface layer 12, which may
be of the same or different material as the
concrete-facing surface layer 8. The (A) core
further comprises an integral stiffener 14, the
stiffener imparting resistance to deflection to the
concrete form panel sheeting. In a preferred
embodiment, the stiffener has substantially
identical length and width dimensions as the core,
the concrete-facing surface layer, and the backside
surface layer. As depicted in Figs. 2B and 2C, the
stiffener preferably has a cross-sectional geometry
that extends from the concrete-form face to the
opposite face of the core, i.e., extends
substantially entirely through the core. Exemplary
wavy, rectangular, triangular, and trapezoidal
stiffener geometries are depicted in Figs. 2D, 2E,
2F, and 2G, respectively. Stiffeners having
corrugated geometries, such as those depicted in
Figs. 2D-2G, provide increased resistance to
deflection compared to a substantially planar
stiffener. Corrugations in multiple directions
(e.g., a waffle-shaped geometry) also are
contemplated for stiffener members. To facilitate
manufacture of a resinous polymer core comprising an
integral stiffener, the stiffener is manufactured
having holes 16 as depicted in Fig. 2F. In an
injection molding manufacturing process, for
example, injected polymer is capable of passing
through the holes to allow for the formation of a
core member having an integral stiffener.
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The panel sheeting of the present
invention is a useful substitute for plywood and
other structural materials wherever such materials
are employed, e.g., for wall, floors, roofs,
ceilings, and the like. In particular, the concrete
form panel sheeting of the present invention is
useful for constructing prefabricated, modular
concrete forms; for constructing custom "job-built"
concrete form networks and frameworks; for shoring
applications; and for other concrete forming
applications in which reusable concrete form panel
sheeting may be employed. A number of exemplary
embodiments for employing the inventive panel
sheeting are depicted in Figs. 3-14, as described
below.
The invention is also embodied in a
removable concrete form comprising (D) a concrete
form support frame structure attached to the basic
embodiment [(A) + (B)] and/or the embodiment [(A) +
(B) + (C)] of the novel concrete form panel
sheeting. The support frame imparts rigidity to the
panel sheeting, protects edges and corners of the
panel sheeting from damage, provides support and
strength to the panel sheeting such that it can
withstand increased pressure from fresh (liquid)
concrete, and/or provides attachment structure for
interconnecting the concrete form to additional
concrete forms.
In the concrete form depicted in Fig. 3,
the concrete form frame includes edge members 32,
34, 36, and 38 that surround the circumference of
the panel sheeting 40 to protect the edges and
corners of the panel sheeting from damage and to
provide structure for attachment to additional
concrete forms. As shown in Figs. 3-6, such edge
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members are attached to the panel sheeting 40 by
means of a screw 42, rivet 44, nail 46, or like
member. Referring to Figs. 3 and 6, the rivet 44
extends through the concrete-facing surface layer 8,
the core 2, the backside surface layer 12, and
through an attachment flange 48 that is attached to
or integral with the frame edge member 38 and that
is adjacent to the backside of the panel sheeting
40. Adjacent edge members themselves are attached
to or integral with each other, e.g., by screws,
solder, or weld. To provide additional support for
the concrete form panel sheeting, adjacent edge
members may be joined by corner supports 50, and
opposite edge members may be joined by one or more
cross-supports 52. For ease in handling, such
frames may be provided with one or more handles 54.
Such a frame may be manufactured from a metal such
as steel or aluminum; alternative materials will be
apparent to those in the art.
Referring to Figs. 3, 7, and 8, a concrete
form network for pouring a wall or other concrete
member of a desired height and width is constructed
by interconnecting a plurality of concrete forms,
end to end. Thus, edge members 32, 34, 36, and 38
are formed having one or more apertures 80. Two
forms are connected by inserting connecting hardware
82 through the aligned apertures 80 of the forms and
securing the connecting hardware 82 with additional
connecting hardware 82A. Connecting hardware as
depicted herein permits construction workers to
quickly join adjacent forms for pouring concrete,
and subsequently disassemble such forms quickly
after the concrete has cured.
The thickness of a concrete member is
determined by the distance between the oppositely-
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oriented concrete-facing surfaces 8A and 8B of
concrete form networks 100A and 100B that have been
assembled as described above. This distance is
maintained, and the oppositely-oriented form
networks are attached, using spacers (or "ties") 110
oriented perpendicular to the panel sheetings of the
networks and attached to the edge members 32, 34,
36, and/or 38 of forms that comprise each network.
More particularly, the edge members have one or more
recesses 112, and the recesses of the abutting edge
members of two adjacent concrete forms in a network
define a channel through which a spacer 110 is
placed. To secure a spacer to a form network (Fig.
8), connecting hardware 82 is passed first through
an aperture in the recessed portion 112C of the edge
member 36C of a first concrete form in the network,
then through an aperture in the spacer 110, then
through an aperture in the recessed portion 112D of
the edge member 32D of an abutting concrete form in
the network. The connecting hardware is in turn
secured with additional connecting hardware 82A. By
securing each spacer to two oppositely-oriented form
networks 100A and 100B in the manner described, a
secure concrete form framework is provided, defining
a hollow or cavity or void for pouring concrete, to
form a concrete member.
Numerous variations of the modular
concrete form depicted in Fig. 3 are known in the
art, and can be fitted with concrete form panel
sheeting of the present invention. For example, in
an embodiment depicted in Fig. 9, frame edge members
32, 34, 36, and 38 are attached to the backside face
6 (or the backside surface layer, if employed) of
the panel sheeting 40, and the edges 132 of the
panel sheeting are exposed. When such forms are
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interconnected to form a concrete form network, the
panel sheeting edges 132 of adjacent forms fit flush
against each other, with no interruption by frame
edge members. The concrete form depicted in Fig. 9
has, in addition to cross-supports 52, perpendicular
cross-supports 152. Apertures 154 in the edge
members 32, 34, 36 and 38 facilitate connection of
adjacent forms in a network (e.g., using a nut and
bolt).
Fig. 10 depicts a concrete form having a
frame with no edge members. Cross-supports 52 are
attached to the backside of the panel sheeting 40 by
means of rivets 44. The construction of a concrete
form network with a plurality of the forms is
facilitated by recesses 180 in the concrete form
panel sheeting, corresponding recesses 112 in the
cross-support frame members, pivoting attachment
hardware 182, and flanges 184. As depicted in Figs.
10 and 11, adjacent concrete forms are connected by
pivoting the attachment hardware 182 around the
rivet 44 such that the attachment hardware recess
186 interlocks with the flange 184 on an adjacent
concrete form. Two oppositely-oriented concrete
form networks are attached with spacers 188 passed
through the recesses 180 and 112 in the concrete
form panel sheeting and cross-supports. The spacers
are secured to the form network by passing
attachment hardware flange 190 through a recess 192
in the spacer.
One may also construct concrete form
networks and frameworks without modular concrete
forms, using the concrete form panel sheeting of the
present invention. For example, Fig. 12 depicts a
concrete form framework, comprising two concrete
form networks, erected atop a cement footing 196.
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Adjacent concrete form panel sheets 40A, 40B, and
40C are interconnected with rods 204 and further
secured with waler beams 208 constructed of, e.g.,
aluminum or lumber. Spacers 210 pass through
apertures 212 in the panel sheeting. The rods 204,
in turn, pass through apertures defined by the
spacers. Thus, the rods and spacers cooperate to
prevent opposite form networks 200A and 200B from
separating when liquid concrete is poured into the
hollow defined by the concrete form framework, but
the rods themselves are not physically attached to
the panel sheeting with, e.g., a nail, screw, rivet,
or the like. Additional top spacers 216 cooperate
with the rods, walers, and spacers 210 to maintain
the fixed positions of the opposite form networks
that comprise the concrete form framework.
Additionally, the concrete form panel
sheeting of the present invention has excellent
utility as a plywood substitute in the construction
of custom "job-built" concrete form networks and
frameworks. As depicted in Fig. 13, the panel
sheeting 40A and 40B in job-built networks and
frameworks is interconnected using metal bars (e.g.,
steel or aluminum bars), wooden beam supports, or
the like. The supports 250 are attached to the
panel sheeting to maintain the sheeting in a fixed
position and to provide load-bearing support, and
connected to each other with additional supports 252
to erect concrete,form networks and frameworks of
any desired size or shape. Job-built concrete form
networks and frameworks are well-known in the art,
e.g., for the construction of bridges and dams, and
may be connected to prefabricated concrete forms if
desired. The lighter concrete form panel sheeting
preferred for the present invention is particularly
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advantageous, compared to plywood, in many job-built
applications because relatively thick (e.g., 2.86 cm
(1.125 inches) or more) sheeting is often employed
in such applications, and because such panel
sheeting is manipulated without attached frame
structures during assembly and disassembly of the
concrete form networks and frameworks.
Typically, plywood concrete form panel
sheeting is planar and rectangular in shape, e.g.,
0.61 m x 2.44 m(2' x 8') in dimension. This size
and shape has proven useful for pouring, e.g.,
concrete walls having essentially planar surfaces,
and this is a preferred shape and dimension for the
concrete form panel sheeting and concrete forms of
the present invention. Nonetheless, from the
description herein it will be apparent that the
concrete form panel sheeting of the present
invention can be made to have essentially any
desired shape and dimension, and a steel or other
frame can readily be constructed to match any shape
of panel sheeting that is constructed. Frame
adapters can be constructed to attach adjacent
frames at preselected angles.
Shoring concrete form networks for pouring
horizontal concrete members (e.g., bridges,
ceilings, decks, and the like), constitute another
significant application for the concrete form panel
sheeting of the present invention. As depicted in
Fig. 14, a typical shoring structure includes a
tower comprising two support frameworks 300A and
300B strengthened with cross braces 302 and topped
with joists 304 for supporting the shoring surface
or "deck" 306 comprised of concrete form panel
sheeting. Adjustable jacks 310 on the vertical
support framework members 312 permit precise
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leveling of the horizontal support framework members
314 and joists. Concrete form panel sheeting is
laid across the horizontal joists which, in
cooperation with attached side panels 316, define a
cavity or hollow or void for pouring the horizontal
concrete member. It will be understood that the
concrete form panel sheeting of the present
invention is useful for other shoring applications,
e.g., adjustable horizontal shoring used to
construct concrete bridges between two points, post
shoring, and the like.
Referring again to the inventive concrete
form panel sheeting of Figs. 2 and 3, the core (A)
of the panel sheeting comprises a resinous polymer.
By "resinous polymer" is meant any suitable polymer
resin. Preferred resinous polymers are
thermoplastic resins.
The term "thermoplastic resin" is intended
to include any suitable thermoplastic resin,
particularly engineering thermoplastic resins
possessing superior mechanical properties. Such
resins include, but are not limited to, homopolymers
or copolymers of polyphenylene ethers, aromatic
polycarbonates, polyesters, polyamides,
polyarylates, polyetherimides, polysulfones,
polyolefins, combinations of more than one of the
foregoing, and combinations of one or more of the
foregoing with an alkenyl aromatic polymer.
The polyphenylene ether (PPE) (commonly
referred to as polyphenylene oxide) resin is
normally a homopolymer or copolymer having units of
the formula
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Qõ, a
0
Q
wherein Q, Q',
Q", and are independently selected from the
group consisting of hydrogen, halogens,
hydrocarbons, halohydrocarbons, hydrocarbonoxys, and
halohydrocarbonoxys; and n represents the total
number of monomer units and is an integer of at
least about 20, and more usually at least 50.
The polyphenylene ether resin can be
prepared in accordance with known procedures, such
as those described in U.S. Pat. Nos. 3,306,874 and
3,306,875, from the reaction of phenols, including
but not limited to: 2,6-dimethylphenol; 2,6-
diethylphenol; 2,6-dibutylphenol; 2,6-
dilaurylphenol; 2,6-dipropylphenol; 2,6-
diphenylphenol; 2-methyl-6-tolylphenol; 2-
methoxyphenol; 2,3,6-trimethylphenol; 2,3,5,6-
tetramethylphenol, 2,3,5,6-tetraethylphenol and 2,6-
diethoxyphenol.
Each of these may be reacted alone to
produce the corresponding homopolymer, or in pairs
or with another phenol to produce the corresponding
copolymer.
Examples of the homopolymers include:
poly(2,6-dimethyl-l,4-phenylene ether),
poly(2,6-diethyl-l,4-phenylene ether),
poly(2,6-dibutyl-1,4-phenylene ether),
poly(2,6-dilauryl-1,4-phenylene ether),
poly(2,6-dipropyl-1,4-phenylene ether),
poly(2,6-diphenyl-1,4-phenylene ether),
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poly(2-methyl-6-tolyl-l,4-phenylene
ether),
poly(2-methyl-6-methoxy-1,4-phenylene
ether),
poly(2-methyl-6-butyl-1,4-phenylene
ether),
poly(2,6-dimethoxy-1,4-phenylene ether),
poly(2,3,6-trimethyl-l,4-phenylene ether),
poly(2,3,5,6-tetramethyl-l,4-phenylene
ether),
poly(2,3,5,6-tetraethyl-1,4-phenylene
ether), and
poly(2,6-diethoxy-1,4-phenylene ether).
Examples of the copolymers include
especially those of 2,6-dimethylphenol with other
phenols, such as poly(2,6-dimethyl-co-2,3,6-
trimethyl-1,4-phenylene ether) and poly(2,6-
dimethyl-co-2-methyl-6-butyl-1,4-phenylene ether).
For purposes of the invention, an
especially preferred family of polyphenylene ethers
includes those having alkyl substitution in the two
positions ortho to the oxygen ether atom, i.e.,
those of the above formula where Q and Q' are alkyl,
most preferably having from 1 to 4 carbon atoms.
Illustrative members of this class are:
poly(2,6-dimethyl-1,4-phenylene)ether;
poly(2,6-diethyl-1,4-phenylene)ether;
poly(2-methyl-6-ethy1,1,4-phenylene)ether;
poly(2-methyl-6-propyl-1,4-
phenylene)ether;
poly(2,6-dipropyl-1,4-phenylene)ether;
poly(2-ethyl-6-propyl-1,4-phenylene)ether;
and the like.
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A highly preferred polyphenylene ether
resin for purposes of the present invention is
poly(2,6-dimethyl-1,4-phenylene)ether.
Low density foams comprising polyphenylene
ether or its copolymers as the primary high polymer
component blended with low molecular weight
additives, such as triaryl phosphates, fatty amides,
plasticizers, brominated BPA derivatives, brominated
diphenyl ethers, oligomeric styrenics and
hydrogenated derivatives thereof, or esters are also
included within the scope of polymers for
constructing the core of the invention.
The thermoplastic polyphenylene ether
resin can be used alone or modified (e.g., in
combination with) at least one other substance,
preferably with a polymer, more preferably with an
alkenyl aromatic polymer. The term "alkenyl
aromatic polymer" is intended to encompass
homopolymers as well as copolymers and terpolymers
of alkenyl aromatic compounds with one or more other
materials. Preferably, the alkenyl aromatic polymer
is based at least in part on units of the formula
R5 CR1 = CHR2
R6
R R3
wherein R1 and R2 are selected from the group
consisting of lower alkyl or alkenyl groups of from
1 to 6 carbon atoms and hydrogen; R3 and R4 are
selected from the group consisting of chloro, bromo,
hydrogen, and lower alkyl of from 1 to 6 carbon
atoms; R5 and R6 are selected from the group
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consisting of hydrogen and lower alkyl and alkenyl
aromatic groups of from 1 to 6 carbon atoms; or R5
and R6 may be concatenated together with hydrocarbyl
groups to form a naphthyl group.
The above will encompass styrene, as well
as homologs and analogs of styrene. Specific
examples include, in addition to styrene,
chlorostyrene, bromostyrene, alpha-methyl styrene,
para-methyl styrene, vinyl styrene, divinyl-benzene
and vinyl naphthalene. Substantially atactic
styrene is especially preferred.
The term "alkenyl aromatic" is intended to
include modified alkenyl aromatic compounds, such as
rubber modified, high impact alkenyl aromatic resins
known in the art. Suitable rubber modifiers, which
can be in admixture or interpolymerized with the
alkenyl aromatic resin, include natural rubber, as
well as synthetic rubbers, such as polyisoprene,
polybutadiene, polychloroprene, ethylene-propylene-
diene terpolymers (EPDM rubber), styrene-butadiene
copolymers (SBR rubber), styrene-acrylonitrile
copolymers (SAN), ethylene-propylene copolymers (EPR
rubber), acrylonitrile rubbers, polyurethane rubbers
and polyorganosiloxane (silicone) rubbers.
Polyphenylene ether (PPE) resins and
polystyrene (PS) resins are combinable in wide
proportions, e.g., from about 1 to 99 to about 99 to
about 1 parts by weight. It is contemplated,
however, that low density compositions of the
present invention comprise at least two weight
percent PPE (based upon the weight of PPE and PS
taken together). Compositions containing less than
two weight percent PPE are considered to be
primarily polystyrene compositions and do not
generally exhibit the preferred property
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improvements associated with PPE/PS blends. It is
well-known in the art and well-described in the
literature that the addition of PPE to polystyrene
blends offers improvements in impact strength,
flammability ratings, tensile strength and other
mechanical properties. Conversely, polystyrene is
typically blended with polyphenylene ether resins to
offer better processability for many thermoplastic
processes.
Typical PPE/PS blends useful in the
practice of the present invention comprise between
10 to 90 percent, and preferably 15 to 80 percent by
weight PPE and 90 to 10 percent, preferably 80 to 15
percent by weight PS based upon the weight of the
two resins taken together. More preferably, blends
of 15 to 50 percent PPE and 85 to 50 percent PS are
employed. Such PPE/PS blends are well described in
the literature, including U.S. Patent No. 3,383,435
to Cizek.
The polyphenylene ether resin, with or
without the alkenyl aromatic resin, may further
comprise a flame retarding agent. Such flame
retarding agents are well-known in the art and, in
general, may be selected from the group consisting
of halogen-containing (e.g., chlorine-and/or
bromine-containing) compounds, phosphorous-
containing compounds (e.g., organophosphate
compounds), nitrogen-containing compounds (e.g.,
melamine), and fluoropolymers (e.g., PTFE). The
flame retardant agent may be used alone or in
combination with a flame retardant synergist such as
an antimony compound (e.g., antimony trioxide), a
molybdenum compound, hydrated alumina, and the like.
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As stated above, the term "thermoplastic
resin" includes aromatic polycarbonates. The
aromatic polycarbonates can be polymers of dihydric
phenols and carbonate precursors. The dihydric
phenols that can be employed are bisphenols such as
bis(4-hydroxyphenol) methane, 2,2-bis(4-
hydroxyphenyl) propane (hereinafter referred to as
bisphenol-A), 2,2-bis(4-hydroxy-3-methylphenyl)
propane, 4,4-bis(4-hydroxyphenyl) heptane, 2,2-
bis(4-hydroxy-3,5-dichlorophenyl) propane and 2,2-
bis(4-hydroxy-3,5-dibromophenyl) propane; dihydric
phenol ethers such as bis(4-hydroxyphenyl) ether,
bis(3,5-dichloro-4-hydroxyphenyl) ether, etc.;
dihydroxydiphenols such as p,p'-dihydroxydiphenyl,
3,3'-dichloro-4,41-dihydroxydiphenyl; dihydroxyaryl
sulfones such as bis(4-hydroxyphenyl) sulfone,
bis(3,5-dimethyl-4-hydroxyphenyl) sulfone; dihydroxy
benzenes such as resorcinol and hydroquinone; halo-
and alkyl-substituted dihydroxy benzenes such as
1,4-dihydroxy-2,5-dichlorobenzene, 1,4-dihydroxy-3-
methylbenzene, etc.; and dihydroxy diphenyl
sulfoxides such as bis(4-hydroxyphenyl) sulfoxide
and bis(4-hydroxyphenol) sulfoxide and bis(3,5-
dibromo-4-hydroxyphenol) sulfoxide. A variety of
additional dihydric phenols are also available to
provide carbonate polymers and are disclosed in U.S.
Pat. Nos. 2,999,835; 3,028,365 and 3,153,008.
Also suitable for preparing the aromatic
carbonate polymers are copolymers prepared from any
of the above which have been copolymerized with
halogen-containing dihydric phenols such as 2,2-
bis(3,5-dichloro-4-hydroxyphenyl) propane, 2,2-
bis(3,5-dibromo-4-hydroxyphenol) propane. Also
employed in the practice of the invention may be
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blends of any of the above materials to provide the
aromatic carbonate polymer.
The carbonate precursor may be either a
carbonyl halide, a carbonate ester, or a
haloformate. The carbonyl halides which can be
employed herein are carbonyl bromide, carbonyl
chloride, and mixtures thereof. Typical of the
carbonate esters which may be employed herein are
diphenyl carbonate; di-(halophenyl) carbonates such
as di-(chlorophenyl) carbonate, di-(bromophenyl)
carbonate, di-(trichlorophenyl) carbonate, di-
(chloronaphthyl) carbonate, and di-(tribromophenyl)
carbonate; di-(alkylphenyl) carbonates such as di-
(tolyl) carbonate, di-(naphthyl) carbonate, phenyl
tolyl carbonate and chlorophenylchloronaphthyl
carbonate, or mixtures thereof. The haloformates
suitable for use herein include bis-haloformates of
dihydric phenols (bischloroformates of hydroquinone)
or glycols (bis-haloformates of ethylene glycol,
neopentyl glycol, or polyethylene glycol). While
other carbonate precursors will occur to those
skilled in the art, carbonyl chloride, also known as
phosgene, is preferred. The polycarbonates are
prepared by methods well-known to those skilled in
the art.
The polyesters include linear saturated
condensation products of diols and dicarboxylic
acids, or reactive derivatives thereof. Preferably
they will comprise condensation products of aromatic
dicarboxylic acids or esters and aliphatic diols.
It is also possible to use polyesters such as
poly(1,4-dimethylolcyclohexane dicarboxylates, e.g.,
terephthalates). In addition to phthalates, small
amounts, e.g., from 0.5 to 15% by weight, of other
aromatic dicarboxylic acids, such as naphthalene
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dicarboxylic acid, or aliphatic dicarboxylic acids,
such as adipic acid, can also be present in the
compositions. The diol constituent can likewise be
varied in the preferred embodiments, by adding small
amounts of cycloaliphatic diols. In any event, the
preferred polyesters are well-known as film and
fiber formers, and they are provided by methods
outlined in U.S. Pat. No. 2,465,319 and U.S. Pat.
No. 3,047,539 and elsewhere. The preferred
polyesters will comprise a poly(alkylene
terephthalate, isophthalate or mixed isophthalate-
terephthalate, e.g., up to 30 mole t isophthalate),
the alkylene groups containing from 2 to 10 carbon
atoms, e.g, poly(ethylene terephthalate) or
poly(1,4-butylene terephthalate).
Also included are poly(butylene
terephthalate) copolyester resins. Among the units
which can be present in the poly(butylene
terephthalate) copolyester resins are: aliphatic
dicarboxylic acids, e.g., of up to 50 carbon atoms,
including cycloaliphatic, straight and branched
chain, acids, such as adipic acid,
cyclohexanediacetic acid, dimerized C16-C18
unsaturated acids (which have 32 to 36 carbon
atoms), trimerized such acids, and the like. Among
the units in the copolyesters can also be minor
amounts derived from aromatic dicarboxylic acids,
e.g., of up to 36 carbon atoms, such as isophthalic
acid. In addition to the 1,4-butylene glycol units,
there can also be minor amounts of units derived
from other aliphatic glycols and polyols, e.g., of
up to 50 carbon atoms, including ethylene glycol,
propylene glycol, glycerol and cyclohexanediol.
Such copolyesters can be made by techniques well-
known to those skilled in the art.
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The polyamide resins useful in the
practice of the present invention are a generic
family of resins known as nylons, characterized by
the presence of an amide group (-CONH-) Nylon-6 and
nylon-6,6 are the generally preferred polyamides and
are available from a variety of commercial sources.
Other polyamides, however, such as nylon-4, nylon-
12, nylon-6,10, nylon-6,9, or others such as the
amorphous nylons may be useful for particular
applications.
The polyolefin resin useful in the
practice of the present invention includes
polyethylenes, polypropylenes, polyisobutylenes,
copolymers of olefins, such as of ethylene and
propylene, as well as copolymers of olefins (e.g.,
ethylene) and organic esters such as ethylene vinyl
acetate, ethylene ethyl acetate, ethylene
methylacrylate, and the like. These are
commercially available or are otherwise prepared
from known teachings.
It will also be understood that additives
may be incorporated into the resins used to
construct the panel sheeting of the present
invention. Such additives include rubbery impact
modifiers, flame retarding agents, blowing agents
(e.g., pentane, propane), stabilizers for thermal,
color, and radiation (e.g., UV radiation) stability,
anti-oxidants, processing aids, plasticizers, anti-
static agents, reinforcing and extending fillers,
pigments, surfactants, nucleants, lubricants, and
others that will be apparent to those of ordinary
skill.
A useful resinous polymeric material for
formation of the concrete form panel sheeting core
is selected by consideration of a material's
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physical properties, which can be measured with standard
mechanical tests and compared, for reference, against the
physical properties of conventional IDO plywood concrete
form panel sheeting. More particularly, concrete form
panel sheeting desirably is relatively rigid, so as to
withstand the lateral force exerted on a concrete form by
fresh (liquid) concrete. In particular, to comply with
American Concrete Institute (ACI) standards, a concrete
form (comprising concrete form panel sheeting) cannot
flex more than 0.16 cm (1/16 of an inch) or more than
1/360 the length of the form's longest dimension. A
typical 0.61 m x 2.44 m x 1.27 cm (2' x 8' x 1/211)
concrete form desirably is capable of withstanding, e.g.,
47,880 Pascals (Pa) [1000 lbs./ft2] of pressure, and
greater strength is desirable because it permits the
concrete to be poured more quickly. While an integral
stiffener and one or more surface layers of the panel
sheeting of the invention contribute(s) significantly to
the strength of the panel sheeting, a core material
should be selected that contributes to this property of
the panel sheeting. At the same time, selection of a
material that is less dense (and hence lighter in weight)
than HIDO plywood is highly preferred.
Concrete form panel sheeting preferably is
attached to a concrete form frame or support structure by
means of screws, nails, rivets, or the like.
Consequently, preferred core materials are sufficiently
ductile such that a nail hole can be drilled, or
preferably formed by hammering a nail, into the core
without cracking the core. Moreover, the core should
possess good nail/screw retention characteristics. The
core also must withstand the physical abuse likely to be
encountered in the field, particularly in an embodiment
wherein the
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panel sheeting consists of a core and a concrete-
facing surface layer, but no backside surface layer.
The core material also should be resistant
to the environment encountered when pouring
concrete. Thus, the material should be capable of
withstanding temperatures of, e.g., -7 C to 82 C
(20 F to 180 F) without cracking, warping,
appreciable shrinkage, or appreciable expansion.
Preferably, the core material also is capable of
withstanding temperatures below -29 C (-20 F), to
permit year-round outdoor storage of the panel
sheeting and concrete forms made therefrom.
Additionally, the behavior of the core material at
different temperatures (e.g., expansion or
contraction) should be compatible with the behavior
of the other materials with which the core
cooperates during a pour, such as the concrete-
facing surface layer, a backside surface layer, an
integral stiffener, and/or a wooden or metal frame.
The core is largely protected from
concrete by the concrete-facing surface layer, but
not completely protected. For example, nail holes
in the concrete-facing surface layer and edges of
the panel sheeting are locations where the core
material is likely to contact liquid concrete. In
panel sheeting that is constructed without a
backside surface layer, the opposite (backside) face
of the core is likely to be inadvertently contacted
by concrete as well, e_g., by splashing. Thus, the
3C core should be non-absorbent and non-reactive with
water, with fresh concrete (notably lime), and with
any external form release agents (e.g., diesel fuel,
Magic Kote form release) that may be employed at
the site. Preferably, the core material is
recyclable with only minimal cleaning.
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Additionally, the core material preferably
is selected to be compatible with the material
selected to form a concrete-facing surface layer
(B); the material selected to form an optional
backside surface layer (C); and the material
selected to form an optional integral stiffener.
For example, the core and concrete-facing surface
layer most preferably are formed from materials that
will form a strong, chemically-resistant bond.
Also, the materials are selected to have similar
coefficients of thermal expansion and contraction.
Because a highly preferred aspect of the
inventive panel sheeting is that it possess reduced
weight, relative to conventional HDO plywood panel
sheeting, a highly preferred resinous polymer core
is a foam (e.g., closed or open cell) polymer core.
A closed cell polymer is preferred. Processes for
foaming (expanding) resinous polymers (particularly
polystyrene-type polymers and PPE/PS blends) are
well-known in the art and described in the
literature. For example, methods are known for
imbibing polymer resin beads with a blowing agent,
which beads may be expanded (e.g., in a heating
operation) at a later time for formation into a
foamed article. (See, e.g., Bopp et al., U.S. Patent
No. 5,095,041, incorporated herein by reference).
The foam core itself may be formed from the
expandable or expanded resinous polymers by well-
known means, e.g., by extrusion (see, e.g., Allen et
al. U.S. Patent No. 4,857,390, which may be referred to
for further details, or as a molded article (e.g., by
expandable bead molding or steam chest molding).
For the foregoing reasons, exemplary
compositions for forming the thermoplastic polymer
core of the inventive structural member comprise
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foamed or foamable modified polyphenylene ether
resins, expanded or expandable polyolefins, (e.g.,
expanded polypropylene, expanded polyethylene),
expanded or expandable polyolefin copolymers or
blends (e.g. polystyrene/polyethylene blends such as
ARCELTM), or foamed or foamable polyurethanes.
Preferred compositions for forming the thermoplastic
polymer core of the inventive structural member
comprise foamed or foamable modified polyphenylene
ether resins having compositions described above.
More preferably, the core is formed from PPE/PS
blends. Such low density foamable compositions (and
the processing thereof) are described in the
literature, see, e.g., U.S. Patent Nos. 4,727,093
(Allen et al.); 4,874,796 (Allen et al.); 4,920,153
(Allen et al.); 4,927,858 (Joyce & Kelley),
4,968,466 (Allen et al.); 4,992,482 (Joyce &
Kelley); 5,064,869 (Bopp et al.); 5,130,340 (Allen);
and 5,190,986 (Allen), which may be referred to for
further details. Most preferably, the core is
formed from high performance expandable PS/PPE
particles, developed by General Electric Company
(GE) and Huntsman Corporation (HC) and commercially
available from HC (Peru, Illinois) as GECETO
expandable engineering resins.
To produce GECET* resins, GE Plastics
produces a base resin, to which HC imbibes a blowing
agent and various additives to produce a class of
resin beads having the following general
composition:
poly(phenylene oxide) (PPO resin),
1-99 wt.%;
polystyrene (PS), 1-99 wt.%;
pentanes, 6.5 wtA max.;
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halogenated organic flame retardants, 0.9 wt.%
max.;
plasticizers, 0.4 wt.% max.;
external and internal lubricants, 0.3 wt.%
max.; and
Color index Pigment Black #7, 0 - 5 wt.%.
GECET* resin beads of 0.0254 - 0.254 cm (0.01 - 0.1
inches) in diameter, having a specific gravity of 1.14-
1.18 and a softening point of 102 - 232 C (215 - 250 F),
are commercially available in three grades: GECET* F100
RESINS, GECET* F200 RESINS, and GECET* F300 RESINS.
Typical properties of these three materials, as provided
by the manufacturer, are shown in Figs. 15A-15I, Figs.
16A-16I, and Figs. 17A-17J, respectively. All three
GECET' grades possess excellent resistance to acids (e.g.,
concentrated HC1, concentrated HZS04, acetic acid, and
oleic acid), bases (e.g., 30a KOH), petroleum products
(e.g., diesel fuel, kerosene, motor oil, and Murphy's Oil
Soap), and lubricating oils (e.g., mineral oil and,
cotton seed oil). Grade F100 resin, having a density
range of 40-641 kg/m3 (2.5-40 lbs./ft3), offers the widest
range of mechanical properties and moderate heat
resistance. Grade F200, having a density range of 56-641
kg/m3 (3.5-40 lbs./ft3), offers medium heat resistance
(usable with temperatures up to 110 C (230 F)). Grade
F300 has a density range of 72-641 kg/m3 (4.5-40 lbs/ft3)
and is usable at temperatures up to 121 C (250 F). For
reasons of cost, GECET' F100 and GECET' F200 resins are
preferred for the present invention. For more rapid
processing, GECET' F300 is preferred.
GECET' resin beads may be processed into a foam
core of pre-selected dimensions by adapting techniques
well-known in the art for processing other foam bead
resins, e.g., expandable polystyrene
CA 02254984 1998-11-10
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(EPS) resins. One preferred technique involves
processing the GECET' resin beads into a core member using
the manufacturer's (Huntsman's) recommended pre-expansion
and steam chest molding process.
First, impregnated GECET' resin beads at a bulk
density of about 641 kg/m' (40 lbs./ft3) are heated with
steam or hot air in a steam-jacketed pre-expander or
similar apparatus to expand the beads to a desired
density. Final densities of 32-481 kg/rn3 (2-30 lbs/ft3)
preferably 80.1 - 240.3 kg/m3 (5-15 lbs./ft3), and more
preferably 96.1-160.2 kg/m3 (6 - 10 lbs./ft.3) , are
preferred, because cores of lower densities may exhibit
nail retention problems, and cores of greater densities
are undesirably heavy and more expensive to process into
finished panel sheeting. Exemplary processing conditions
using a high temperature steam jacketed expander are
provided in Table I:
TABLE I
Pre-expansion of GECET' resins
GECET' Desired Density Pressure Exposure
Resin Time
(sec.)
F100 96.1-160.2 kg/m3 69-127 kPa 70-80
(6-10 lbs. per ft.') (10-25 PSI)
F200 96.1-160.2 kg/m3 207-241 kPa 50
(6-10 lbs. per ft.3) (30-35 PSI)
F300 96.1-160.2 kg/m3 276-310 kPa 55-70
(6-10 lbs. per ft.3) (40-45 PSI)
To form a molded core, the expanded GECET'
resin beads are injected into a steam chest mold
(which may be coated with Teflori resins or the like
to facilitate removal of molded articles) via vacuum
transfer and fused under pressure to form a core of
CA 02254984 1998-11-10
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desired density. Exemplary molding conditions are
provided in Table II:
TABLE II
Molding pre-expanded GECETO resin into a panel
Cooling Pressure
GECET* kPascal Fusing Cooling
Resin Desired Temp. (Pressure Time Cycle
(sec) Density lbs/ft2) (sec.) Time
F100 64.1-160.2 (232 F) 1.15-1.34 18-22 260-380
kg/m3 111 C (24-28)
(4-10 lbs.
per ft')
F200 64.1-160.2 (240 F) 1.53-1.82 25-30 260-320
kg/m3 116 C (32-38)
(4-10 lbs.
per ft3)
F300 64.1-160.2 (258 F) 2.7 -2.87 30-35 210-230
kg/m3 126 C (56-60)
(4-10 lbs.
per ft3)
It will be understood by those skilled in the art
that the processing conditions given above are
exemplary only, and will vary with equipment, with
the density and dimensions of the formed article,
and the like.
Alternatively, the expanded GECET' resin
beads are formed into a core by extruding the beads
with an extruder to form a sheet of desired
thickness (e.g., 0.635-3.81 cm (0.25" to 1.5")), and
cutting the sheet into core members of desired
dimensions. To form concrete form panel sheeting of
desired sizes (e.g., sheets of 0.61 m x 2.44 m x
1.27-3.81 cm (2' x 8' x 0.5" to 1.5")), extrusion
may be a preferred method for reasons of cost.
Other methods for constructing a GECET core,
including pultrusion methods, will be apparent to
those in the art. A preferred supplier of a GECET
foam core suitable for the present invention is
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Huntsman Corp. in conjunction with Diversified
Plastics Corp. (Nixa MO).
CARILTM expandable engineering beads,
manufactured and sold by Shell Nederland Chemie B.V.
(The Netherlands) and marketed by GE Plastics Europe
(The Netherlands), comprise an alternative
polystyrene/polyphenylene ether material suitable
for forming the core of the concrete form panel
sheeting. Such beads, supplied in multiple grades
(e.g., CARILTM EX402, CARILTM EX403, CARILTM EX404),
provide heat resistance up to about 120 C (glass
transition temperature of 110 - 130 C for the
aforementioned grades). The raw spherical beads
(which contain about 6% of pentane expansion agent)
are pre-expanded with steam, dried, and molded
(preferably in a Teflon-coated mold) to form a core
of desired density, using conventional pre-expansion
and molding techniques for such materials.
Commercially available, extruded Noryl
foam boards (GE Plastics) also are contemplated as
materials for construction of the core member.
Polystyrene copolymer systems, such as
poly(styrene-co-maleic anhydride) copolymers
(SMA's), comprise a less-preferred family of
materials for construction of the core member.
Structural members formed from such materials may
absorb undesirably large volumes of water and may
change shape in response to changes in water
content.
In a preferred embodiment the core (A) of
the concrete form panel sheeting includes an
integral stiffener, which stiffener imparts
resistance to deflection to the panel sheeting.
Such stiffeners may be composed of, e.g.,
commercially-available sheet metal (aluminum or
CA 02254984 1998-11-10
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steel, for example) or polymer resin materials (including
fiber-reinforced polymer materials) such as the polymer
materials described herein for face sheets and back
sheets.
In a preferred embodiment, commercially-
available aluminum or steel sheet metal is stamped to
form a stiffener member having (i) a length and width
corresponding to the length and width dimensions of the
concrete form panel sheeting (e.g., 0.61 m x 2.44 m (2' x
8')); (ii) a desired corrugation geometry (e.g.,
trapezoidal); (iii) a corrugation depth less than or
equal to the thickness of the core member of the concrete
fonn panel sheeting; and (iv) holes to facilitate
manufacture of the core via injection molding procedures.
For example, a concrete form panel sheetinq having the
dimensions of 0.61 m x 2.44 m x 1.27 cm (2' x 8' x 1/2")
may be constructed having a face sheet of 0.61 m x
2.44 m x 0.16 cm (2' x 8' x 1/16"), a back sheet of
0.61 m x 2.44 m x 0.16 cm (2' x 8' x 1/16"), a core of
0.61 m x 2.44 m x 0.95 cm (2' x 8' x 3/8"), and a 0.61 m
x 2.44 m(2' x 8') stiffener integral with the core and
having corrugation to provide the stiffener with .95 cm
(3/8") depth. An exemplary aluminum stiffener for a 0.61
m x 2.44 m x 1.27 cm (2' x 8' x 1/2") panel is stamped
from 14 gauge aluminum and has a trapezoidal corrugation
geometry that repeats about every 5-7;4 cm (2 - 3 inches).
To manufacture a core member having an integral
stiffener, the stamped stiffener member is placed into a
steam chest mold. Expanded GECET' resin beads are
injected into the steam chest mold as described above,
the filling of the mold being facilitated by the
perforations (e.g., 0.635 - 5.1 cm (0.25 - 2 inches) 4-n
diameter) in the stiffener. Referring again to Fig. 2F,
in a preferred embodiment, the stiffener has one to f-Lve
large holes 18 (e.g., 20 - 40 mm in diameter), spaced ~_-o
correspond with the location of one to five polymer bead
injectors of
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the steam chest mold, and a plurality of smaller
holes 16 (e.g., 10 - 20 mm in diameter) to
facilitate flow-through during the molding process
(to form an integral core structure) while
maintaining the strength of the stiffener. Fusion
of the beads under pressure forms a core having an
integral stiffener.
To form the basic embodiment of concrete
form panel sheeting depicted in Fig. 1, the core (A)
is bonded to a concrete-facing surface layer (B).
The concrete-facing surface layer preferably
comprises a resinous polymer, and more preferably a
thermoplastic resin, as defined previously for the
core. More specifically, the concrete-facing
surface layer preferably comprises a modified
polyphenylene ether resin. However, numerous other
materials, including engineered thermoplastic resins
and thermosets may be suitable. Fiber-reinforced
thermoplastics and thermosets are suitable as well.
The necessary physical properties of this layer
provide additional guidelines for selecting the most
useful polymers.
For example, the concrete form panel
sheeting of the present invention is intended to be
reusable, and consequently an essential property of
the concrete-facing surface layer is that the layer
be adapted to be contacted by fresh (liquid)
concrete and to release from the concrete after the
concrete has cured. By "concrete" is meant those
concretes used in the construction industry, which
typically contain hydraulic cements (e.g., Portland
cement) having some or all of the following common
constituents, which chemically react during the
curing process of the concrete: calcium oxide
(CaO); silicon dioxide (Si02); aluminum oxide
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(A1203); ferric oxide (Fe203); magnesium oxide (MgO);
sulfur trioxide (SO3): sodium oxide (Na20); potassium
oxide (K20), carbon dioxide (C02); and water.
Nonetheless, it is contemplated that the panel
sheeting of the invention may be employed in
conjunction with masonry cements, oil well cements,
refractory cements, and other specialty cements
known in the art, without departing from the
teachings herein.
For a surface layer to be "adapted to be
contacted by fresh (liquid) concrete," the surface
layer must, at a minimum, be resistant to chemical
or thermal degradation by the concrete, before and
during curing thereof. The concrete-facing surface
layer should neither react with nor absorb water,
fresh concrete, or components thereof.
A surface layer is "adapted to release
from concrete after the concrete has cured" if
concrete form panel sheeting comprising the surface
layer can be separated from the cured concrete (1)
without damaging the concrete member, while (2)
maintaining the integrity of the panel sheeting,
such that the panel sheeting subsequently can be
reused. More preferred embodiments of panel
sheeting comprise a surface layer requiring less
force to release from cured concrete. Preferably,
the surface layer is adapted to release from cured
concrete with minimal application of an external
form release agent or without application of an
external form release agent.
The concrete facing surface layer must
also be capable of withstanding other conditions
encountered by concrete forms in the field. For
example, the concrete-facing surface layer desirably
is impact resistant, scratch resistant, and
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sufficiently ductile such that it can be neatly
penetrated with a drill or nail, all over the broad
temperature ranges likely to be encountered at a job
site.
Additionally, to ensure that the panel
sheeting has a long useful life, the core and
concrete-facing surface layers should be made from
compatible materials to ensure that a strong,
chemically resistant bond may be formed
therebetween. Lighter concrete-facing surface
layers are preferred, though this feature is more
important for the core, which generally occupies the
major volume of the panel sheeting.
A series of mechanical tests, designed to
simulate environmental conditions encountered during
the useful life of a concrete form, were performed
to select the preferred concrete form panel sheeting
surface materials of the invention. These tests may
be repeated readily to screen alternative materials,
and standard laboratory mechanical tests may be used
to pre-screen such alternative materials. The tests
used to arrive at preferred materials of the
invention included a concrete adhesion test to
measure the ease with which a material releases from
cured concrete; a penetration test to measure the
ease with which a nail may be driven through and
removed from a material and the cleanness of
penetration; scratch-resistance tests; impact
resistance tests; and cleanup tests to measure the
ease with which a material can be cleaned for reuse
in a subsequent concrete pour.
More particularly, to perform the concrete
pouring and adhesion test, a concrete form framework
was assembled using industry-standard, steel-framed
and plywood-faced concrete forms, resting on a
CA 02254984 1998-11-10
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plywood base. A 0.32 - 1.9 cm (1/8 to 3/4) inch thick
test sheet of a candidate surface material (13.3 -
24.8 cm [5.25 to 9.75"] long x 17.8 - 29.8 cm [7 to
11.75" inches] high) was labelled and attached to the
concrete-form face of one of the concrete forms, using
double-sided tape. As a control, similar adhesion tests
were performed with 1.27 cm (1/2") thick samples of high
density overlay Douglas Fir plywood, cut to the same
dimensions and treated with Symons Magic Kote form oil.
Concrete (5 bag #57 AE 3000PSI mix) was
shoveled into the hollow defined by the concrete forms to
cover all but the top 1.27 cm (1/2 inch) of the test
sheet samples. Care was taken not to dislodge the
samples, but the conditions were otherwise similar to
those encountered in the field. The concrete was cured
in place in a warehouse where temperatures varied from
approximately 10-21 C (50 to 70 F). After curing the
concrete for varying lengths of time ranging from two to
ten days, the concrete form framework was disassembled.
Since concrete typically is cured only for, e.g., 24
hours prior to removing forms, the longer curing periods
simulate adverse pouring conditions.
To varying degrees, the test samples adhered to
the concrete after the concrete form framework was
disassembled. To measure the relative adhesion of
various materials, a clip was attached to the center of
the top edge of the sample and also connected to a 222
Newtons (N) (50 pound) capacity hanging straight scale,
calibrated in 2.22 N (8 ounce) increments. Force was
applied to the scale assembly, in a direction
perpendicular to the plane of the test sample until the
sample sheet released from the concrete. A separate
observer recorded the maximum force applied before
release. This adhesion test was re:Deated as
CA 02254984 1998-11-10
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many as 29 times for a given sample, and was performed on
samples that had been test scratched as described below
and samples that had been frozen to 30 F to simulate
varying environmental conditions that are encountered in
the field. Noteworthy changes to samples in the course
of testing, such as warping and the formation of surface
condensation, were recorded. Of course, a 0.61 m x
2.44 m(2' x 8') concrete form has about 55 times the
surface area of, e.g., a 15.24 cm x 17.78 cm (6" x 7")
sample of a surface material, and full-size forms are
expected to demonstrate a comparable increase in adhesion
as compared to such test sample, under comparable
conditions.
An evaluation of the surface of the poured and
cured concrete was conducted following some of the
adhesion tests, and samples were given a rating between 1
and 10. A sample was rated a"1" if the concrete surface
was dirty with a dull finish, and a"10" if the concrete
surface was very clean with a high-gloss finish. Most
samples left a gloss finish on the concrete immediately
after removal, which changed to a dull finish after 1-2
days, as is observed with standard plywood concrete form
panel sheeting.
The general appearance of test samples was
recorded following the above-described adhesion tests,
and a clean-up test was conducted on the samples by
wiping the samples with a clean dry cotton shop rag and
evaluating the relative force required to dislodge any
adhering concrete. Where concrete adhered after
significant force was applied, the sample was cleaned
using water and the ease of clean-up was re-evaluated.
In either case, observations were recorded as to whether
the cleaning left a film, residue, or powder.
CA 02254984 1998-11-10
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As to general appearance, samples were given a
rating of "1" if a heavy concrete build-up was observed
following the adhesion test, and a rating of "10" if the
samples were relatively clean, with little build-up (or a
rating between 1 and 10). Samples were given a relative
clean-up rating inversely proportional to the force
needed to clean the sample. Samples that were difficult
to clean or very scratched were rated "1"; samples that
were easily cleaned with few visible scratches were rated
"10."
Penetration tests were conducted at 30 F and
70 F by placing test samples of the dimensions described
above against a wood backing and driving a 16-penny steel
nail through the sample using a standard carpenter's
hammer. The nail was then removed by hand. The test
samples were examined for undesirable fracturing, and
were subjectively evaluated for ease of nail-removal.
The cleanliness of nail penetration also was evaluated.
A sample was given a penetration rating of "1" if
penetration was rough and multiple fractures were
observed. A rating of "10" was given to samples that
were penetrated smoothly with no observable fractures.
Two scratch-resistance tests were performed
using a 17.78 cm x 6.35 cm x 20.32 cm (7" x 2.5" x 8")
steel block weighing 18 kg (40 pounds) and attached to
(a) a nail, and (b) sandpaper. A 16-penny nail was
welded in a hole through the block so that the nail's
point protruded approximately 0.64 cm (0.25 inches) from
the largest surface. An 0.32 cm (1/8 inch) thick test
sample of material was attached with double-sided tape to
a 0.61 m x 3.7 m x 3.8 cm (2' x 12' x 1.5") pine board,
and the steel block was dragged across the surface of the
sample. Using a microscope, the width of the scratch
imparted by the nail was
CA 02254984 1998-11-10
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recorded, and the scratch was subjectively rated from 1
to 10, where a"1" (poor) rating was defined as a deep,
wide, crooked scratch with debris visible on its edges,
and a"10" (excellent) rating was defined as a shallow,
narrow, straight, and clean scratch.
For the sandpaper scratch-resistance test, a
30.5 cm x 45.7 cm (12" x 18") sheet of 60 SIC Resin E-CL
sandpaper was attached to a different surface of the
steel block, and the block was dragged across separate
test samples eight times. The resulting scratches were
rated on the same relative scale, with a"1" being given
for samples that had multiple, deep scratches and a"10
for samples with few, shallow scratches.
Blunt-end and sharp-point impact-resistance
tests were conducted on samples placed flat against a
GECET' backing (96 kg/m3 [6 lb. /ft3 density] ) using a
1.28 kg (2 lb., 13 oz.,) steel stake, one end having a
flat surface 1.9 cm (0.75") in diameter and the other end
tapered to a point 0.2 cm (0.08") in diameter. The stake
was dropped vertically from a height of 1.2 m (four feet)
above the sample (measured from the lower end of the
stake), providing an impact energy of 15.25 Joules (J)
(11.25 foot pounds), and the sample was evaluated for
fracturing and depth of penetration. A sample was given
an impact rating of "1" if it was completely fractured or
punctured, and a rating of "10" if it was unfractured or
received an insignificant puncture. The impact
resistance tests were conducted at -1 C (30 F) and 21 C
(70 F) on samples, after concrete had been poured and
cured against the samples twice.
The foregoing durability tests (penetration,
scratch-resistance and impact-resistance tests) were
designed to mimic field conditions that might be
encountered by the panel
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sheeting of a concrete form. One can pre-screen
potential concrete-facing surface layer materials
for penetration properties, scratch-resistance, and
impact-resistance using standard laboratory
mechanical tests, in addition to the tests outlined
above.
The foregoing battery of tests was
conducted on samples of numerous materials to
determine optimum concrete-facing surface layer
materials. Such tested materials included
polyethylenes (PE), polypropylenes (PP), glass-
reinforced polypropylenes (e.g., AZDEL0 materials
(Azdel Inc., Shelby, N.C., U.S.A.)), polyvinyl
chloride (PVC), polyamides, polytetrafluoro-
ethylenes (PTFE), acrylonitrile-butadiene-styrene
(ABS) polymers, high impact polystyrenes (HIPS),
modified polyphenylene ethers (including Noryl
resins from General Electric Co., Plastics Division)
and GECET resins), Delrin acetal resins (Du Pont,
Wilmington DE), spray coatings over GECET resins,
painted coatings, and urethane-coated aluminum. Of
the materials tested, the non-expanded, modified PPE
resins were preferred, as explained below.
Polypropylene materials released well from
concrete and were easy to clean, but demonstrated a
tendency to shatter at low temperatures in impact
tests. Such materials also may undergo undesirable
post-crystallization and warp in the sunlight or
when exposed to excessive heat. Polyethylene
materials provided acceptable results in the above-
battery of tests, but performed poorly on release
from concrete after several pours. Polyolefin
surface materials in general (e.g., PE and PP
materials) have excellent concrete-releasing
characteristics and hydrophobicity, but are less
CA 02254984 1998-11-10
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preferred because they do not strongly bond with the
preferred GECETO resin core members of the invention and
because of a tendency to warp if post-crystallization
occurs. The Azdel- materials bonded GECETO resin cores
more favorably, but also shattered at low temperatures.
Azdel- thermoplastic composite materials (and
other continuous and/or chopped filament glass fiber-
reinforced polypropylene homopolymer materials or the
like) are preferred face sheet materials by virtue of
their superior strength properties. Azdelo thermoplastic
composites comprise 80 - 20o polypropylene, 20 - 80%
fibrous glass (consisting principally of oxides of
silicon, aluminum, calcium, boron, and magnesium fused in
an amor-phous vitreous state), and 0 - 5 o antioxidants,
pig-ments, and processing aids; have a melting point of
164 C (327 F); and a specific gravity of 1.08-1.30.
Typical physical properties of exemplary, commercially-
available Azdelo products are depicted in Tables IIA -
IIC:
TABLE IIA
AZDEL D-R401-BO1
PROPERTY TYPICAL UNIT METHO
DATA D
MECHANICAL
Tensile Strength 1.29x10g Pa ASTM
(18.7) (ksi) D-638
Tensile Elongation 2.5 o ASTM
at break D-638
Tensile Modulus 6.38x109 Pa ASTM
(925) (ksi) D-638
Poisson's Ratio .361 ASTM
D-638
Flexural Strength 1.91x10g Pa ASTM
(27.7) (ksi) D-790
Flexural Modulus 6.56x109 Pa ASTM
(951) (ksi) D-790
Compresive 1.19x10fi Pa AS'I'M
Strength (17.2) (ksi) D-695
CA 02254984 1998-11-10
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AZDEL D-R401-B01
PROPERTY TYPICAL UNIT METHO
DATA D
IMPACT
Izod Impact, 811 N-m/m ASTM
notched, 23 C (15.2) (ft-lb/in) D-256
(73 F), 0.317cm
(0.125")
Multiaxial Impact ASTM
(0.125" thickness) D-
3763
Max. Load 3759 N
(845) (lbs.)
Energy Max. Ld 15.3 J
(11.3) (ft-lbs)
Energy @ Failure 28.6 J
(21.1) (ft-lbs)
THERMAL
HDT, 1820 kPa 153 C ASTM
(264 psi) (309) ( F) D-648
PHYSICAL
Glass Content by 40.0 % Ashin
Weight g
Specific Gravity, 1.19 - ASTM
solid D-792
Mold Shrinkage 0.1-0.3 ASTM
D-955
Basis Weight 4.4 kg/mZ
(0.90) (lbs/ftZ)
FDT = heat deflection temperature
i i
CA 02254984 1998-11-10
- 46A -
TABLE IIB
AZDEL D-II421-BO1 (directionalized fibers)
PROPERTY (Measured TYPICAL UNIT METHOD
in longitudial DATA
direction)
MECHANICAL
Tensile Strength 2.25x105 kPa ASTM D-638
(32.6) (ksi)
Tensile Elongation 2.5 s ASTM D-638
at break
Tensile Modulus 1.01x10, kPa ASTM D-638
(1457.7) (ksi)
Poisson's Ratio 0.377 ASTM D-638
CA 02254984 1998-11-10
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TABLE IIB
AZDEL D-II421-BOl (directionalized fibers)
PROPERTY (Measured TYPICAL UNIT METHOD
in longitudial DATA
direction)
Flexural Strength 2.32x105 kPa ASTM D-790
(33.7) (ksi)
Flexural Modulus 7.45x106 kPa ASTM D-790
(1080.3) (ksi)
Compressive 1.36x105 kPa ASTM D-695
Strength (19.7) (ksi)
IMPACT
Izod Impact, (30.8) (ft- ASTM D-256
notched, 23 C lbs/in)
(73 F), .317cm 1644 N-m/m
(0.125")
Multiaxial Impact ASTM D-3763
(0.317 cm (0.125")
thickness)
Max. Load 6913 N
(1554) (lbs.)
Energy Max. Ld 38.1 J
(28.1) (ft-lbs)
Energy @ Failure 58.2 J
(42.9) (ft-lbs)
THERMAL
HDT, 1820kPa 158 C ASTM D-648
(264 psi) (316) ( F)
PHYSICAL
Glass Content by 42.0 Ashing
Weight
Specific Gravity 1.21 - ASTM D-792
Mold Shrinkage 1-3 ASTM D-955
Basis Weight 4.64 Kg/m2
(0.95) (lbs/ft2)
HDT = heat deflection temperature
CA 02254984 1998-11-10
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TABLE IIC
AZDEL D-U421-BO1 (directionalized fibers)
PROPERTY (Measured TYPICAL UNIT METHOD
in transverse DATA
direction)
MECHANICAI.,
Tensile Strength 9.03x104 kPa ASTM D-638
(13.1) (ksi)
Tensile Elongation 2.3 % ASTM D-638
at break
Tensile Modulus 5.30x106 kPa ASTM D-638
(768.8) (ksi)
Poisson's Ratio 0.361 ASTM D-638
Flexural Strength 1.57x105 kPa ASTM D-790
(22.7) (ksi)
Flexural Modulus '.46x106 kPa ASTM D-790
(792.0) (ksi)
Compressive 9.38x104 kPa ASTM D-695
Strength (13.6) (ksi)
IMPACT
Izod Impact, (13.5) (ft-lb/in) ASTM D-256
notched, 23 C 721 N-m/m
(73 F), 0.317cm
(0.125")
Multiaxial Impact ASTM D-3763
0.317cm ((0.125")
thickness)
Max. Load 6913 N
(1554) (lbs.)
Energy Max. Ld 38.1 J
(28.1) (ft-lbs)
Energy @ Failure 58.2 J
(42.9) (ft-lbs)
THERMAL
HDT, 1820kPa 143 C ASTM D-648
(264 psi) (289) ( F)
PHYSICAL
Glass Content by 42.0 % Ashing
Weight
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- 48A-
TABLE IIC
AZDEL D-II421-BO1 (directionalized fibers)
PROPERTY (Measured TYPICAL UNIT METHOD
in transverse DATA
direction)
Specific Gravity, 1.21 - ASTM D-792
solid
Mold Shrinkage .1-.3 ASTM D-955
Basis Weight 4.64 Kg/m2
(0.95) (lbs/ftZ)
HDT = heat deflection temperature
CA 02254984 1998-11-10
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Compression molding, stamping, thermoforming, and other
techniques known in the art and/or provided by the
manufacturer may be used to fabricate Azdel* materials
into a face sheet for use in the panel sheeting of the
invention.
PTFE materials are less preferred because of
sub-optimal performance in the battery of durability
tests.
ABS materials performed well in concrete
adhesion tests, but are less preferred for reasons of
cost and because of sub-optimal performance in the
durability tests. Also, ABS materials have an
undesirable tendency to become embrittled from UV
radiation exposure.
DELRIN acetal resins released well from concrete
in concrete adhesion tests, but performed below average
in the battery of durability tests.
Polystyrene materials performed suboptimally in
durability tests and were difficult to clean, and hence,
are less preferred.
HIPS materials are less preferred due to their
softness. These materials performed average or below
average in impact-resistance tests and scratch-resistance
tests, and large holes and a minor fracture were formed
in the penetration test. Most importantly, HIPS
materials performed poorly relative to preferred
materials in concrete adhesion tests, particularly after
6 or more pours against a sample, and also became more
difficult to clean.
Urethane coatings in general (sprayed and
painted onto GECET', and urethane-coated aluminum) bonded
strongly to concrete in the adhesion test, and therefore
are less preferred. For example, 66.7-116 N (15-26
pounds) of force were required to remove urethane
coated aluminum samples from cured concrete in the
CA 02254984 1998-11-10
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above-described adhesion test, using samples that
had concrete poured and cured against them 0-4
times. These results were considerably inferior to
the 8.9-22 N (2-5 pounds) of force usually required
to remove samples of preferred materials that had
concrete poured and cured against them a comparable
number of times. Moreover, urethane coatings do not
add nearly as much strength to the the panel
sheeting as more preferred rigid surface materials.
Coated aluminum materials in general are
less preferred as concrete-facing surface layers,
due to their excessive weight, relative to preferred
Noryl resin materials.
Uncoated GECET* F300 samples were
unsatisfactory, as they strongly adhered to concrete
and performed poorly in clean-up and durability
tests.
Polyamide materials (nylons) performed
above average in some durability tests and in
concrete adhesion tests, but scratched easily and
display a tendency to absorb water, making such
materials less preferred.
Samples of Noryl" resins from GE Plastics
demonstrated the best overall performance of surface
materials tested. Moreover, such materials bond
extremely well to GECET' resins because such
materials are themselves modified PPE resins.
Preferred Noryle resins include PPE/HIPS blends
(e.g., Noryl* PX0844 resins, Noryl* PX1718 resins,
Noryl* PX4685 resins, and Noryl* MX5314 resins) ;
filled PPE blends (e.g., mineral-filled PPE blends,
such as Noryl0 HS1000X resins, (clay-filled, impact
modified, flame-retardant PPE resins)); and
PPE/polyamide blends (e.g., Noryl GTX*909 resins
(PPE/nylon blends)).
CA 02254984 1998-11-10
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More particularly, Noryl* PX0844 resins,
commercially available from GE Plastics, are non-
flame retardant PPE/HIPS blends that typically
possess the properties depicted in Table IIIA,
according to the manufacturer:
TABLEIIIA
NORYL* RESIN: PX0844
PROPERTY TYPICAL UNIT METHOD
DATA
MECHANICAL
Tensile Strength, 49642 kPa ASTM D 638
yield, Type I, 0.317cm (7200) (psi)
(0.125")
Te nsile Elongation, 42.0 ASTM D 638
break, Type I, 0.317cm
(0.125")
Flexural Strength, 75842 kPa ASTM D 790
yield, (0.250") 0.635cm (11000) (psi)
Flexural Modulus, 2240796 kPa ASTM D 790
0.635cm (0.250") (325000 (psi)
Hardness, Rockwell R 114 - ASTM D 785
IMPACT
Izod Impact, notched, 235 N-m/m ASTM D 256
23 C (73 F) (4.4) (ft-
lb/in)
Izod Impact, notched, 133 N-m/m ASTM D 256
(-40 F) -40 C (2.5) (ft-
lb/in)
THERMAL
HDT, 455 kPa (66 psi) , 121 C ASTM D 648
0.635cm (0.250") (250) ( F)
unannealed
HIDT, 1820kPa (264 psi) 113 C ASTM D 648
0.635cm (0.250") , (235) ( F)
unannealed
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- _7
TABLE III A
NORYL* RESIN: PX0844
PROPERTY TYPICAL UNIT METHOD
DATA
CTE, flow, 0-100 C 4.1 E-5 in/in-F ASTM E 831
(32 F to 212 F)
PHYSICAL
Specific Gravity, solid 1.06 - ASTM D 792
Water Absorption, 24 0.100 % ASTM D 570
hours @ 23 C (73 F)
Mold Shrinkage, flow, 5-7 in/in E- ASTM D 955
0.317cm (0.125") 3
HDT = heat deflection temperature
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The manufacturer's suggested injection
molding guidelines are summarized in Table III B:
TABLE III B
NORYL* RESIN: PX0844
INJECTION MOLDING GUIDELINES
MELT TEMPERATURE 1288-304 C (550-580 F)
BARREL TEMPERATURE
Nozzle 288-304 C (550-580 F)
Front 293-304 C (560-580 F)
Middle 282-299 C (540-570 F)
Rear 277-288 C (530-550 F)
MOLD TEMPERATURE 49-82 C (120-180 F)
DRYING BASICS, min 2-4 hrs 99-107 C (210-225 F)
INJECTION PRESSURE kPa (psi) 68948-110316 (10000-
16000)
HOLDING PRESSURE kPa (psi) 62053-89632 L9000-
13000)
BACK PRESSURE kPa (psig) 345-689 (50-100)
SCREW SPEED (rpm) 25-75
% SHOT SIZE TO BARREL CAPACITY 40-75
CLAMP TONNAGE (tons per sq. in) 4.2-7 Mkg/m2 (3-5)
INJECTION SPEED MED-FAST
MOLD SHRINKAGE (in/in) 0.005-0.007
CUSHION (in) (0.125) 0.317cm
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Noryl- PX1718 resins, commercially
available from GE Plastics, comprise PPE/HIPS blends
to which triarylphosphate ester flame retardants
have been added. The manufacturer reports that
these resins typically possesses the properties
depicted in Table IV A:
TABLE IV A
NORYL* RESIN: PX1718
PROPERTY TYPICAL UNIT METHOD
DATA
MECHANICAL
Tensile Strength, 58605 kPa ASTM D
yield, Type I, 0.317cm (8500) (psi) 638
(0.125")
Tensile Elongation, 25.0 % ASTM D
break, Type I 0.317cm 638
(0.125")
Flexural Strength, 93079 kPa ASTM D
yield, 0.317cm (13500) (psi) 790
(0.125")
Flexural Modulus, 2516586 kPa ASTM D
0.317cm (0.125") (365000) (psi) 790
Hardness, Rockwell R 116 - ASTM D
785
IMPACT
Izod Impact, notched, 240 N-m/m ASTM D
23 C (73 F) (4.5) (ft- 256
lb/in)
Izod Impact, notched, 133 N-m/m ASTM D
-40 C (-40 F) (2.5) (ft- 256
lb/in)
Gardner Impact, 23 C 17.6 J ASTM D
(73 F) (13) (ft-lbs) 3029
Gardner Impact, -40 C 8.1 J ASTM D
(-40 F) (6) (ft-lbs) 3029
THERMAL
CA 02254984 1998-11-10
- 53A-
TABLE IV A _7
NORYL* RESIN: PX1718
PROPERTY TYPICAL UNIT METHOD
DATA
HIDT, 455 kPa (66 psi), 118 C ASTM D
0.635cm (0.25011), (245) ( F) 648
unannealed
HI~T, 1820kPa (264 102 C ASTM D
psi), 0.635cm (215) ( F) 648
(0.250"), unannealed
CA 02254984 1998-11-10
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TABLE IV A
NORYL' RESIN: PX1718
PROPERTY TYPICAL UNIT METHOD
DATA
CTE, flow, -40 to 93 C 3.8 E-5 in/in-F ASTM E
(-40 F to 200 F) 831
PHYSICAL
Specific Gravity, 1.09 - ASTM D
solid 792
Water Absorption, 24 0.070 % ASTM D
hours @ 23 C (73 F) 570
Mold Shrinkage, flow, 5-7 in/in E-3 ASTM D
(0.125") 0.317cm 955
ELECTRICAL
Dielectric Strength, 630 V/mil ASTM D
in oil, (125 mils) 149
3.17 mm
Dielectric Constant, 2.79 -- ASTM D
60 Hz 150
Dissipation Factor, 60 0.0031 - ASTM D
Hz 150
The manufacturer's suggested injection
molding guidelines are summarized in Table IVB:
TABLE IV B
NORYL* RESIN: PX1718
PRELIMINARY DATA: DTUL 220F
INJECTION MOLDING GUIDELINES
SPECIFIC GRAVITY 1.09
MOLD SHRINKAGE 0.005-0.007 in/in
MELT TEMPERATURE 260-288 C (500 F-550 F)
CYLINDER TEMPERATURES
Rear I 254-266 C (490 F-510 F)
Middle 260-271 C (500 F-520 F)
Front 266-277 C (510 F-530 F)
Nozzle 260-282 C (500 F-540 F)
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ir- TABLE IV B
NORYIL* RESIN: PX1718
MOLD TEMPERATURE 171-93 C (160 F-200 F)
DRYING BASICS'
Temperatures 104-110 C (220 F-230 F)
Times 2-4 hours
INJECTION PRESSURE 82737-103421 kPa (12000-15000 psi)
HOLDING PRESSURE 62052-82737 kPa (9000-12000 psi)
BACK PRESSURE 345-689 kPa (50-100 psi)
INJECTION SPEED MED-FAST
SCREW SPEED 40-80 rpm
SHOT SIZE TO 40-80 s
BARREL CAPACITY
CLAMP TONNAGE 4.2-7 Mkg/m2 (3-5 tons psi)
MOLD SHRINKAGE 5-7 in/in E-3
CUSHION 0.317 cm (0.125 in)
RECOMNENDED MIN 0.15 cm (0.060 in)
PART THICKNESS
Noryl' MX5314 resins, commercially
available from GE Plastics, are flame-retardant
PPE/HIPS blends fire retarded with triarylphosphate
esters and having a composition and properties
similar to PX1718 resins, except that MX5314 resins
contain post-consumer recycled materials. Table V A
contains typical properties reported by the
manufacturer for MX5314 resins:
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TABLE V A
NORYL* RESIN: MX5314
PROPERTY TYPICAL UNIT METHO
DATA D
MECHANICAL
Tensile Strength, 62053 kPa ASTM
yield, Type I, (9000) (psi) D 638
0.317cm (0.125")
Tensile Elongation, 26.0 % ASTM
break, Type I 0.317cm D 638
(0.125")
Flexural Strength, 98595 kPa ASTM
yield, .635cm (14300) (psi) D 790
(0.250")
Flexural Modulus, 2620008 kPa ASTM
0.635cm (0.250") (380000) (psi) D 790
IMPACT
Izod Impact, notched, 149 N-m/m ASTM
(73 F) 23 C (2.8) (ft-lb/in) D 256
THERMAL
HDT, 1820kPa (264 100 C ASTM
psi), 0.635cm (212) ( F) D 648
(0.250"), unannealed
PHYSICAL
Specific Gravity, 1.12 - ASTM
solid D 792
Mold Shrinkage, flow, 5-7 in/in E-3 ASTM 7
0.317cm (0.125") D 955
Mold Shrinkage, xflow 5-7 in/in E-3 ASTM
D 955
FL,AME CHARACTERISTICS
UBC Standard 52-4 CC1 - ASTM
D 635
OTHER
L Pre/post Consumer 25 Minimum o FTC
Recycle Content Regs
The manufacturer's injection molding
guidelines are summarized in Table V B.
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TABLE V B
NORYL* RES IN : biX5 314
INJECTION MOLDING GUIDELINES
DRYING 2-4 hrs at 104-110 C (220-230 F),
6 hrs max
TEMPERATURES
Melt 260-288 C (500 F-550 F)
Rear 254-266 C (490 F-510 F)
Middle 260-271 C (500 F-520 F)
Front 266-277 C (510 F-530 F)
Nozzle 260-288 C (500 F-550 F)
Mold 71-93 C (160 F-200 F)
BACK PRESSURE kPa 345-689 (50-100)
(psig)
SCREW SPEED (rpm) 40-80
SUGGESTED SHOT SIZE 40-800 of machine capacity
PURGE: HDPE/PS
Noryle PX4685 resins, commercially
available from GE Plastics, also comprise PPE/HIPS
blends. This low-cost product is made with scrap
materials and will contain variable levels of flame
retardants. Table VI A contains typical properties
reported by the manufacturer for PX4685 resins:
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TABLE VI A
NORYL* RESIN: PX4685
PROPERTY TYPICAL UNIT METHOD
DATA
MECHANICAL
Tensile Strength, 50332 kPa ASTM D
yield, Type I, 0.317cm (7300) (psi) 638
(0.125")
Tensile Strength, 48953 kPa ASTM D
break, Type I, 0.317cm (7100) (psi) 638
(0.125")
Tensile Elongation, 6.0 ASTM D
yield, Type I 0.317cm 638
(0.125")
Tensile Elongation, 24.0 o ASTM D
break, Type I 0.317 638
(0.125")
Flexural Strength, 79979 kPa ASTM D
yield, 0.635cm (0.250") (11600) (psi) 790
Flexural Modulus, 0.635 2289059 kPa ASTM D
cm (0.250") (332000) (psi) 790
IMPACT
Izod Impact, notched, 133 N-m/m ASTM D
(73 F) 23 C (2.5) (ft- 256
lb/in)
THERMAL
HDT, 455kPa (66 psi), 110 C ASTM D
0.635cm (0.250") (230) ( F) 648
unannealed
IDT, 1820kPa (264 psi), 100 C ASTM D
0.635cm (0.250"), (212) ( F) 648
unannealed
Thermal Index, Elec 50 C UL 746B
Prop
Thermal Index, Mech 50 C UL 746B
Prop with impact
Thermal Index, Mech 50 C UL 746B
prop without impact
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TABLE VI A
NORYL* RESIN: PX4685
PROPERTY TYPICAL UNIT METHOD
DATA
PHYSICAL
Specific Gravity, solid 1.10 - ASTM D
792
Mold Shrinkage, flow, 5-7 in/in E-3 ASTM D
0.317cm (0.125") 955
FLAME CHARACTERISTICS
UL File Number, USA E121562 - -
94HB Rated (tested 0.16 cm UL 94
thickness) (0.063) (inch)
The manufacturer's injection molding
guidelines are summarized in Table VI B:
TABLE VI B
NORYL* RESIN: PX4685
INJECTION MOLDING GUIDELINES
MOLD SHRINKAGE (in/in E-3) 5-7
DRYING 2-4 hrs at 88-96 C (190-
205 F)
TEMPERATURE
MELT 277-293 C (530-560 F)
Rear 266-277 C (510-530 F)
Middle 271-282 C (520-540 F)
Front 282-293 C (540-560 F)
Nozzle 277-293 C (530-560 F)
Mold 49-82 C (120-180 F)
INJECTION SPEED MED-FAST
INJECTION PRESSURE kPa 55158-110316
(psi) (8000-16000)
HOLDING PRESSURE kPa (psi) 48263-68948
(7000-10000)
BACK PRESSURE kPa (psig) 345-689 (50-100)
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TABLE VI B
NORYL" RESIN: PX4685
SCREW SPEED (rpm) 25-75
SUGGESTED SHOT SIZE 40-75%- to machine capacity
CLAMP TONNAGE Mkg/mg2 4.2-7 (3-5)
(tons psi)
Noryl* HS1000X resins, commercially
available from GE Plastics, are flame-retardant,
mineral-filled PPE resins, and typically possess
properties as reported in Table VII A, according to
the manufacturer:
TABLE VII A
NORYL' RESIN: HS1000X
PROPERTY TYPICAL UNIT METHOD
DATA
MECHANICAL
Tensile Strength, 65500 kPa ASTM D
yield, Type I, (9500) (psi) 638
0.317cm (0.125")
Tensile Strength, 51021 kPa ASTM D
break, Type I, (7400) (psi) 638
0.317cm (0.125")
Tensile Elongation, 7.6 ASTM D
yield, Type I 0.317cm 638
(0.125")
Tensile Elongation, 30.0 s ASTM D
break, Type I 0.317cm 638
(0.125")
Flexural Strength, 103421 kPa ASTM D
yield, 0.635cm (15000) (psi) 790
(0.250")
Flexural Modulus, 2895798 kPa ASTM D
11 0.635 cm (0.250") (420000) (psi) 790
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TABLE VII A
NORYLO RESIN: HS1000X
PROPERTY TYPICAL UNIT METHOD
DATA
Hardness, Rockwell R 121 - ASTM D
785
IMPACT
Izod Impact, 1511 N-m/m ASTM D
unnotched, 23 C (28.3) (ft-lb/in) 256
(73 F)
Izod Impact, notched, 133 N-m/m ASTM D
23 C (73F ) (2.5) (ft-lb/in) 256
Instrumented Impact 24.9 J ASTM D
Energy & Peak, 23 C (18.4) (ft-lbs) 3763
(73F )
THERMAL
Vicat Softening Temp, 126 C ASTM D
Rate B (258) ( F) 1525
HIDT, 66 psi, 0.635cm 98 C ASTM D
(0.250") unannealed (209) ( F) 648
HDT, 264 psi, 0.635cm 93 C ASTM D
(0.250"), unannealed (200) ( F) 648
Thermal Index, Elec 100 C UL 746
Prop B
Thermal Index, Mech 85 C UL 746
Prop with impact B
Thermal Index, Mech 100 C UL 746
prop without impact B
PHYSICAL
Specific Gravity, 1.23 - ASTM D
solid 792
Water Absorption, 24 0.070 s ASTM D
hours @ 23 C (73 F) 570
Mold Shrinkage, flow, 5-7 in/in E-3 ASTM D
0.317cm (0.125") 955
ELECTRICAL
Volume Resistivity 1.6 E16 ohm-cm ASTM D
257
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TABLE VII A
NORYIL* RESIN: HS1000X
PROPERTY TYPICAL UNIT METHOD
DATA
Surface Resistivity >1.0 E16 ohm/sq ASTM D
257
Dielectric Strength, 17823 V/mm ASTM D
in oil, 3.17 mm (125 (452) (V/mil) 149
mils)
Dielectric Constant, 3.03 - ASTM D
50 Hz 150
Dielectric Constant, 2.83 - ASTM D
1 MHz 150
Dissipation Factor, 0.0270 - ASTM D
50 Hz 150
Dissipation Factor, 1 0.0070 - ASTM D
kHz 150
The manufacturer's injection molding
guidelines are summarized in Table VII B:
TABLE VII B
NORYL' RESIN: HS1000X
High strength resin. UL94 V-0/5VA rated.
INJECTION MOLDING GUIDELINES
MELT TEMPERATURES 249-282 C (480 F-540 F)
CYLINDER TEMPERATURES
Rear 232-249 C (450 F-480 F)
Middle 243-260 C (470 F-500 F)
Front 254-271 C (490 F-520 F)
Nozzle 260-277 C (500 F-530 F)
MOLD TEMPERATURES 66-82 C (150 F-180 F0
DRYING BASICS
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TABLE VII B
NORYL* RESIN: HS1000X
High strength resin. UL94 V-0/5VA rated.
Temperatures 99 C-104 C (210 F-220 F)
Times 2-4 hours
INJECTION PRESSURE 83-124 MPa 12000-18000 psi
HOLDING PRESSURE 55-83 MPa 8000-12000 psi
BACK PRESSURE 0.35-0.69 MPa 50-100 psi
INJECTION SPEED SLOW-MED SLOW-MED
SCREW SPEED 40-80 rpm 40-80 rpm
SHOT SIZE TO BARREL 40-80 % 40-80%
CAPACITY
CLAMP TONNAGE 4.2-7 Mkg/mZ 3-5 tons psi
(3-5 tons psi)
MOLD SHRINKAGE 0.5-0.7% 5-7 in/in E-3
CUSHION 3 mm 0.125 in
RECOMMENDED MIN 1.70 mm 0.060 in
PART THICKNESS
Noryl" GTX' 909 resins, commercially
available from GE Plastics, are PPE/nylon-6,6 blends
that, according to the manufacturer, typically
possess the properties depicted in Table VIII A:
TABLE VIII A
NORYL GTX' RESIN: GTX909
PROPERTY TYPICAL UNIT METHOD
DATA
MECHANICAL
Tensile Strength, 66879 kPa ASTM D 638
yield, Type I, (9700) (psi)
0.317cm (0.125")
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TABLE VIII A
NORYL* GTX* RES IN : GTX9 0 9
PROPERTY TYPICAL UNIT METHOD
DATA
Tensile Strength, 59984 kPa ASTM D 638
break, Type I, (8700) (psi)
0.317cm (0.125")
Tensile Elongation, 9.0 ASTM D 638
yield, Type I
0.317cm (0.125")
Tensile Elongation, 50.0 ASTM D 638
break, Type I
0.317cm (0.125")
Flexural Strength, 99285 kPa ASTM D 790
yield, 0.635cm (14400) (psi)
(0.250")
Flexural Modulus, 2378691 kPa ASTM D 790
0.635cm (0.250") (345000) (psi)
IMPACT
Izod Impact, 176 N-m/m ASTM D 256
notched, 23 C (3.3) (ft-
(73 F) lb/in)
Izod Impact, 107 N-m/m ASTM D 256
notched, -29 C (2.0) (ft-
(-20 F) lb/in)
Instrumented Impact 40.7 J ASTM D 3763
Energy @ Peak, 23 C (30.0) (ft-lbs)
(73 F)
Instrumented Impact 24.4 J ASTM D 3763
Energy @ Peak, - (18.0) (ft-lbs)
29 C (-20 F)
THERMAL
Vicat Softening 246 C ASTM D 1525
Temp, Rate B (474) ( F)
HDT, 455kPa (66 204 C ASTM D 648
psi), 0.635cm (400) ( F)
(0.250") unannealed
HDT, 1820kPa (264 125 C ASTM D 648
psi), 0 . 635cm (257) ( F)
(0.250") ,
unannealed
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TABLE VIII A
NORYL* GTX RESIN: GTX909
PROPERTY TYPICAL UNIT METHOD
DATA
CTE, flow, -18 to 5.3 E-5 in/in-F ASTM E 831
149 C (0 F to
300 F)
CTE, xflow, (0 F to 4.5 E-5 in/in-F ASTM E 831
300 F) -18 to 149 C
PHYSICAL
Specific Gravity, 1.13 - ASTM D 792
solid
Water Absorption, 0.540 ASTM D 570
24 hours @ 23 C
(73 F)
Water Absorption, 4.40 % ASTM D 570
equilibrium, 23 C
(73 F)
Mold Shrinkage, 13-17 in/in E-3 ASTM D 955
flow, 0.317cm
(0.125")
ELECTRICAL
Volume Resistivity 4.40 E16 ohm-cm ASTM D 257
Surface Resistivity 1.70 E16 ohm/sq ASTM D 257
Dielectric 25631 V/mm ASTM D 149
Strength, in oil, (650) (V/mil)
(125 mils) 3.17 mm
Dielectric 3.27 - ASTM D 150
Constant, 50 Hz
Dielectric 2.76 - ASTM D 150
Constant, 1 MHz
Dissipation Factor, 0.0390 - ASTM D 150
50 Hz
Dissipation Factor, 0.0190 - ASTM D 150
1 MHz
The manufacture injection molding
guidelines are summarized in Table VIII B.
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TABLE VIII B
NORYL* GTX* RES IN : GTX9 0 9
INJECTION MOLDING GUIDELINES
NORYL GTX resin should not be mixed with other grades
of NORYL resins.
BASIC DRYING: (1) - 2-4 hrs at 93 C (200 F), 6 hrs max
TEMPERATURES
Melt (2) 271-293 C (520-560 F)
Rear 260-282 C (500-540 F)
Middle 266-288 C (510-550 F)
Front 271-293 C (520-560 F)
Nozzle (3) 271-293 C (520-560 F)
Mold 66-93 C (150-200 F)
INJECTION lst 68948-137895 kPa (10000-
PRESSURE stage 20000 psi)
2nd 48263-89632 (7000-13000
stage psi)
BACK PRESSURE 345-689 kPa (50-100 psi)
RAM SPEED MED-FAST
SCREW SPEED 40-80 rpm
SHOT SIZE TO 30-60%
BARREL CAPACITY
(4)
NOZZLE SIZE 0.4762cm (0.1875") min
(SHORT OPEN BORE) orifice
REGRIND (must be 25 s
dried also)
PURGE: Polystryene and acrylic regrind are effective
purging materials. Use temperature range
appropriate for particular puring resin.
Notes:
(1) Dry at recommended temperatures and times for
optimum performance.
CA 02254984 1998-11-10
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- Overdrying can cause loss of physical
properties and/or create appearance
defects. Do not exceed recommended basic
drying time and temperature above or:
- 6-12 hrs at 79 C (175 F), 16 hrs. max.
- 8-16 hrs at 66 C (150 F), 24 hrs. max.
- AVOID air circulating tray ovens.
Moisture levels in heated ambient air can
exceed moisture level in the resin itself,
causing moisture ABSORPTION not drying.
(2) Avoid melt temperature in excess of 293 C
(560 F) and residence times over 6-8 minutes
(may affect properties and/or appearance).
(3) Nozzle temperature controls assist in
elimination of drool and premature freeze-off.
(4) Shot sizes in excess of 50% barrel capacity can
lead to difficulties in providing a consistent,
homogenous plastic melt.
The foregoing descriptions of materials,
including preferred materials, will suggest numerous
alternative materials to those skilled in the art.
The battery of mechanical tests described above
enable one skilled in the art to routinely screen
such alternative materials. The representative
adhesion test results provided for a variety of
materials in Table IX further facilitate selection
of alternative samples of materials.
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TABLE IX
Concrete Adhesion Test Results
Sample Force required to release sample from
condition: concrete
Concrete
previously
poured and Preferred Less preferred
cured n times (typical force (typical force
against sample required) required)
n = 0 - 5 0-22.2 N (0-5 lbs) 35.6-111N
e.g., Noryl PX0844 (8-25 lbs)
Noryl* HS1000X e.g.
Noryl* GTX 909 urethane-coated
polypropylene aluminum,
Emeralon RC-370
coated aluminum
n 6 - 10 0-26.7 N (0-6 ibs) ---
e.g., Noryls PX1718
Noryl* MX5314
Noryl* HS1000X
Noryl* GTX 909
n = 11 - 25 0-44.5 N (0-10 lbs) --
e.g., Noryl~ PX0844
Noryl* PX1718
Noryl* GTX*909
Optionally, internal release agents may be
added to resins to improve the ease with which a
surface layer comprising the resin will release from
cured concrete.
A concrete-facing surface layer is formed
from any of the foregoing materials using techniques
known in the art. Such techniques include various
molding techniques, such as compression molding and
injection molding, and more preferably extrusion
techniaues. A preferred concrete-facing surface
layer (face sheet) is constructed from a modified
PPE resin and has a thickness up to about 0.64 cm
(1/4 inch), and preferably a thickness of about 0.16
cm (1/16 inch). A
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preferred supplier of Noryl* face sheet materials of
the present invention is General Electric Plastics.
To form the concrete form panel sheeting
of the present invention, the core and concrete-
facing surface layers are attached together using
any procedure known in the art, including adhesives,
solvent bonding techniques, ultrasonic welding,
radio frequency welding, and the like. Less
preferred methods include staples, fasteners, and
the like. Where attachment is by means of an
adhesive, the composition of the core and surface
layers will dictate appropriate adhesives such as
rubber-based or polystyrene- based adhesives.
Similar considerations apply with respect to
appropriate solvents for solvent bonding techniques.
In an embodiment wherein Azdel (or other
glass fiber-reinforced thermoplastic face sheets)
are employed and are attached to the core by means
of an adhesive, lofting of the Azdel face sheet
(heating of one side to allow the glass fibers to
raise) according to the manufacturer's instructions
may improve adhesion between the Azdel and the
adhesive.
In a preferred embodiment wherein both the
core and concrete-facing surface layer are composed
of modified PPE resins, techniques which form a
unified, integral structure from the laminates are
preferred. Such techniques include, for example,
solvent bonding techniques and ultrasonic welding.
For solvent bonding of such resins, a manufacturer's
recommended solvent combination is 1:1 TCE
(trichloroethylene, 1:1:2 trichloroethylene):MCB
(monochlorobenzene, chlorobenzene). An alternative
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recommendation is 4:1 TCE:MBE mixed with 5-25%
weight/vol. of NORYL* resin.
In a highly preferred method, an adhesive
is applied to the core and/or the concrete-facing
surface layer, which are then stacked upon each
other. The stacked substrates are fed through
rollers under high pressure, or pressed in a press,
to create an integral unit from the parts.
Preferably, the adhesive is a rubber-based adhesive
(e.g., H.B. Fuller Product No. H.L. 2081) or a
polystyrene-based or polystyrene-compatible hot melt
adhesive which is sprayed upon the core and/or
concrete facing surface layer with automatic
spraying equipment. Pressure of 1197-1436 kPa
(25,000 - 30,000 lbs./ftZ) is applied using rollers
or a hydraulic press to create a mechanical and
chemical bond. The bonded product is cured one to
two hours at about 52 C (125 F), while maintaining a
relative humidity at or below 50%. A preferred
finisher for adhering a GECET* foam core to a face
sheet is Diversified Plastics Corporation (Nixa MO).
It will be appreciated that, in an embodiment
wherein the core and concrete-facing surface layer
each comprise a polyphenylene ether/polystyrene
blended resin, the use of a polystyrene-based
adhesive results in an integral panel sheeting
product that will not delaminate from exposure to
water, form oil, concrete lime, and the like.
An adhesive should be selected which has a
cure temperature that does not exceed the heat
deflection temperature of the core or surface layer
resin. Adhesives generally recommended by GE
Plastics for Noryl* resins include methyl
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cyanoacrylate and ethyl cyanoacrylate adhesives
(Permabond Intl. Co., Loctite Corp.); epoxy
adhesives (Bacon Industries, 3M); silicone adhesives
(GE); and acrylic adhesives (Lord Corp.; Loctite).
A backside surface layer (C) optionally
may be attached to the inventive concrete form panel
sheeting, primarily for the purpose of imparting
lateral strength to the panel sheeting to withstand
the lateral force exerted on a concrete form by
fresh (liquid) concrete (i.e., to impart increased
resistance to deflection to the concrete form panel
sheeting). Other means for imparting increased
lateral strength to panel sheeting (e.g., increasing
the thickness or density of the core; increasing the
thickness of the concrete-facing surface layer) will
be apparent. However, attaching a backside surface
layer (backing sheet) is a preferred method for
increasing the flexural strength of the panel
sheeting, while minimizing the increase in mass of
the sheeting.
The optional backside surface layer
contacts wet concrete only incidentally (i.e., from
splashing), and consequently releasability from
cured concrete is of less importance for the
backside surface layer than for the concrete-facing
surface layer (B). Nonetheless, the backside
surface layer preferably possesses the other
desirable physical properties of the concrete-facing
surface layer, including ease of penetration,
scratch-resistance, impact resistance, chemical
resistance, and ease of cleaning. Preferably, the
backside surface layer comprises a material that is
selected to maximize these properties while
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minimizing the weight and cost of the backside
surface layer.
From the foregoing, it will be apparent
that materials that make a useful concrete-facing
surface layer also will make a useful backside
surface layer. Thus, the backside surface layer may
comprise a resinous polymer, particularly a
thermoplastic resin as defined previously for the
core (A) and concrete-facing surface layer (B). The
backside surface layer also may comprise many
additional strength-imparting materials known to
those of ordinary skill, including a thin sheet of
aluminum or other metal, or a fiber-reinforced
resinous material. Preferred backside surface
layers comprise a layer of material identical to the
material used to form the concrete-facing surface
layer, up to about 6.3 mm (1,(") thick, and a sheet of
aluminum up to about 1.6 mm (1/16") thick. The
backside surface layer may be attached to the core
by any known means, including means described above
for attachment of the concrete-facing surface layer
to the core. An aluminum backside surface layer
preferably is attached to the core with an adhesive.
The potential recyclability of the
concrete form panel sheeting of the present
invention (e.g., after wear and tear make further
use of such sheeting impractical) is an advantage
over plywood panel sheeting of the prior art.
Unlike plywood panel sheeting, the polymeric panel
sheeting of the invention will absorb little or no
external form release agent (e.g., form oil), if
such release agents are used at all. Thus, after
cleaning extraneous concrete and removing metal
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fasteners from the "spent" panel sheeting, a
recyclable material exists.
EXAMPLE
Recycling panel sheeting made from
compatible thermoplastic components
A batch of "spent" concrete forms
comprising (A) a GECET core and (B) + (C) one or
more surface layers of a Noryl that is a
PPE/polystyrene blend, adhered to the core by means
of a polystyrene adhesive, are cleaned of extraneous
concrete and metal fasteners. The "spent" panel
sheeting comprises essentially PPE, polystyrene, and
minor additives, and may be recycled without
separation of components. The cleaned panel
sheeting is densified by means well known in the art
(i.e., in a heating step). The densified material
is ground up in a grinder and homogenized by passing
it through an extruder. The extruded material is
cut or ground into pellets and reformed into useful
articles.
EXAMPLE
Recycling panel sheeting made from
incompatible thermoplastic components
The "spent" concrete form panel sheeting
comprises at least two materials that are chemically
incompatible and cannot be recycled together. For
example, the adhesive used to attach a GECET core
to a Noryl surface layer comprises a chemical that
cannot be recycled with modified PPE resins, or the
backside surface layer comprises an aluminum
sheeting that cannot be recycled with a
thermoplastic core. The incompatible adhesive,
metal, or other material is removed by means known
in the art (e.g., with mechanical means, heat,
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solvents, floatation devices or the like).
Recycling then proceeds as in the previous example.
STRENGTH TEST FOR CONCRETE FORM PANEL SHEETING
The following procedure is useful for
measuring the resistance to deflection of concrete
form panel sheeting under conditions designed to
simulate the pressures to which such sheeting is
subjected in concrete forming applications.
Concrete form panel sheeting manufactured according
to the teachings herein (e.g., a 0.61 m x. 2.44 m x
1.27 cm (2' x 8' x 1/2") panel) is inserted into a
standard concrete form frame, such as a frame
depicted in Fig. 3 or Fig. 9. The frame of the form
is then securely locked down (immobilized).
An inflatable air bag having a surface
0.61 m x 2.44 m (2' x 8') in dimension is placed in
contact with the concrete-facing surface of the
concrete form. The air bag is inflated to impart a
controlled pressure (e.g., 10.3 - 72.4 kPa (1.5 -
10.5 pounds per square inch) or more) to the
concrete facing surface, simulating the pressure of
liquid concrete (10.5 PSI corresponds to about 1500
pounds/ft'' of pressure).
Gauges attached to the back of the
concrete form at selected locations (e.g., along the
concrete form frame, and at the center of the panel,
equally spaced between cross-supports and edge
members of the concrete form frame) are used to
measure deflection of the concrete form in response
to the pressure. The air pressure is then released
and the gauges are read to determine whether the
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deflection of the panel is permanent, or whether the
panel regains its original shape.
To provide a baseline for evaluation of
the panel, deflection measurements taken along the
concrete form frame may be subtracted from
measurements taken at the center of the panel. As a
control, measurements are taken under identical
conditions using an identical concrete form wherein
HDO plywood is substituted for concrete form panel
sheeting of the invention.
Modifications and variations may be
apparent to one of ordinary skill from the foregoing
description, which modifications are intended to
come within the scope of the invention as defined in
the appended claims.
